freepascal.compiler/compiler/ogwasm.pas

{
    Copyright (c) 2021 by Nikolay Nikolov

    Contains the WebAssembly binary module format reader and writer

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

 ****************************************************************************
}
unit ogwasm;

{$i fpcdefs.inc}

interface

    uses
      { common }
      cclasses,globtype,
      { target }
      systems,cpubase,
      { assembler }
      aasmbase,assemble,aasmcpu,
      { WebAssembly module format definitions }
      wasmbase,
      { output }
      ogbase,
      owbase;

    type
      TWasmObjSymbolExtraData = class;

      TGlobalInitializer = record
        case typ:TWasmBasicType of
          wbt_i32: (init_i32: Int32);
          wbt_i64: (init_i64: Int64);
          wbt_f32: (init_f32: Single);
          wbt_f64: (init_f64: Double);
      end;

      { TWasmObjSymbolLinkingData }

      TWasmObjSymbolLinkingData = class
      public
        ImportModule: string;
        ImportName: string;

        FuncType: TWasmFuncType;
        ExeFunctionIndex: Integer;
        ExeIndirectFunctionTableIndex: Integer;
        ExeTypeIndex: Integer;

        ExeTagIndex: Integer;

        GlobalType: TWasmBasicType;
        GlobalIsMutable: Boolean;
        GlobalInitializer: TGlobalInitializer;

        IsExported: Boolean;
        ExportName: ansistring;

        constructor Create;
        destructor Destroy;override;
      end;

      { TWasmObjSymbol }

      TWasmObjSymbol = class(TObjSymbol)
        FuncIndex: Integer;
        SymbolIndex: Integer;
        GlobalIndex: Integer;
        TagIndex: Integer;
        AliasOf: string;
        ExtraData: TWasmObjSymbolExtraData;
        LinkingData: TWasmObjSymbolLinkingData;
        TlsGlobalSym: TWasmObjSymbol;
        TlsDataSym: TWasmObjSymbol;
        constructor create(AList:TFPHashObjectList;const AName:string);override;
        destructor Destroy;override;
        function IsAlias: Boolean;
      end;

      { TWasmObjRelocation }

      TWasmObjRelocation = class(TObjRelocation)
      public
        TypeIndex: Integer;
        Addend: LongInt;

        { used during linking }
        FuncType: TWasmFuncType;
        ExeTypeIndex: Integer;
        IsFunctionOffsetI32: Boolean;

        constructor CreateTypeIndex(ADataOffset:TObjSectionOfs; ATypeIndex: Integer);
        constructor CreateFuncType(ADataOffset:TObjSectionOfs; AFuncType: TWasmFuncType);
        destructor Destroy;override;
      end;

      { TWasmObjSymbolExtraData }

      TWasmObjSymbolExtraData = class(TFPHashObject)
        TypeIdx: Integer;
        ExceptionTagTypeIdx: Integer;
        ImportModule: string;
        ImportName: string;
        ExportName: string;
        GlobalType: TWasmBasicType;
        GlobalIsImmutable: Boolean;
        Locals: array of TWasmBasicType;
        EncodedLocals: tdynamicarray;
        constructor Create(HashObjectList: TFPHashObjectList; const s: TSymStr);
        destructor Destroy; override;
        procedure AddLocals(alocals: TWasmLocalsDynArray);
      end;

      { TWasmObjSection }

      TWasmObjSection = class(TObjSection)
      public
        SegIdx: Integer;
        SegSymIdx: Integer;
        SegOfs: qword;
        FileSectionOfs: qword;
        MainFuncSymbol: TWasmObjSymbol;
        CustomSectionIdx: Integer;
        constructor create(AList:TFPHashObjectList;const Aname:string;Aalign:longint;Aoptions:TObjSectionOptions);override;
        function IsCode: Boolean;
        function IsData: Boolean;
        function IsDebug: Boolean;
      end;

      { TWasmFuncTypeTable }

      TWasmFuncTypeTable = class
      private
        FFuncTypes: array of TWasmFuncType;
        function GetCount: Integer;
        function GetItem(Index: Integer): TWasmFuncType;
      public
        destructor Destroy; override;

        function AddOrGetFuncType(wft: TWasmFuncType): integer;
        procedure WriteTo(d: tdynamicarray);
        property Count: Integer read GetCount;
        property Items[Index: Integer]: TWasmFuncType read GetItem; default;
      end;

      { TWasmObjData }

      TWasmObjData = class(TObjData)
      private
        FFuncTypes: TWasmFuncTypeTable;
        FObjSymbolsExtraDataList: TFPHashObjectList;
        FLastFuncName: string;

        function is_smart_section(atype:TAsmSectiontype):boolean;
        function sectionname_gas(atype:TAsmSectiontype;const aname:string;aorder:TAsmSectionOrder):string;
      public
        constructor create(const n:string);override;
        destructor destroy; override;
        function sectionname(atype:TAsmSectiontype;const aname:string;aorder:TAsmSectionOrder):string;override;
        procedure writeReloc(Data:TRelocDataInt;len:aword;p:TObjSymbol;Reloctype:TObjRelocationType);override;
        function AddOrCreateObjSymbolExtraData(const symname:TSymStr): TWasmObjSymbolExtraData;
        function globalref(asmsym:TAsmSymbol):TObjSymbol;
        function ExceptionTagRef(asmsym:TAsmSymbol):TObjSymbol;
        procedure DeclareGlobalType(gt: tai_globaltype);
        procedure DeclareFuncType_Pass0(ft: tai_functype);
        procedure DeclareFuncType_Pass1(ft: tai_functype);
        procedure DeclareFuncType_Pass2(ft: tai_functype);
        procedure DeclareTagType(tt: tai_tagtype);
        procedure DeclareExportName(en: tai_export_name);
        procedure DeclareImportModule(aim: tai_import_module);
        procedure DeclareImportName(ain: tai_import_name);
        procedure DeclareLocals_Pass0(al: tai_local);
        procedure DeclareLocals_Pass1(al: tai_local);
        procedure WriteLocals_Pass2(al: tai_local);
        procedure symbolpairdefine(akind: TSymbolPairKind;const asym, avalue: string);override;
        property FuncTypes: TWasmFuncTypeTable read FFuncTypes;
      end;

      { TWasmObjOutput }

      TWasmObjOutput = class(tObjOutput)
      private
        FData: TWasmObjData;
        FWasmRelocationCodeTable: tdynamicarray;
        FWasmRelocationCodeTableEntriesCount: Integer;
        FWasmRelocationDataTable: tdynamicarray;
        FWasmRelocationDataTableEntriesCount: Integer;
        FWasmRelocationDebugFrameTable: tdynamicarray;
        FWasmRelocationDebugFrameTableEntriesCount: Integer;
        FWasmRelocationDebugInfoTable: tdynamicarray;
        FWasmRelocationDebugInfoTableEntriesCount: Integer;
        FWasmRelocationDebugLineTable: tdynamicarray;
        FWasmRelocationDebugLineTableEntriesCount: Integer;
        FWasmRelocationDebugAbbrevTable: tdynamicarray;
        FWasmRelocationDebugAbbrevTableEntriesCount: Integer;
        FWasmRelocationDebugArangesTable: tdynamicarray;
        FWasmRelocationDebugArangesTableEntriesCount: Integer;
        FWasmRelocationDebugRangesTable: tdynamicarray;
        FWasmRelocationDebugRangesTableEntriesCount: Integer;
        FWasmRelocationDebugStrTable: tdynamicarray;
        FWasmRelocationDebugStrTableEntriesCount: Integer;
        FWasmSymbolTable: tdynamicarray;
        FWasmSymbolTableEntriesCount: Integer;
        FWasmSections: array [TWasmSectionID] of tdynamicarray;
        FWasmCustomSections: array [TWasmCustomSectionType] of tdynamicarray;
        FWasmLinkingSubsections: array [low(TWasmLinkingSubsectionType)..high(TWasmLinkingSubsectionType)] of tdynamicarray;
        procedure WriteWasmSection(wsid: TWasmSectionID);
        procedure WriteWasmCustomSection(wcst: TWasmCustomSectionType);
        function IsExternalFunction(sym: TObjSymbol): Boolean;
        function IsExportedFunction(sym: TWasmObjSymbol): Boolean;
        procedure WriteFunctionCode(dest: tdynamicarray; objsym: TObjSymbol);
        procedure WriteSymbolTable;
        procedure WriteRelocationCodeTable(CodeSectionIndex: Integer);
        procedure WriteRelocationDataTable(DataSectionIndex: Integer);
        procedure MaybeWriteRelocationDebugTable(cst: TWasmCustomSectionType; SectionIndex: Integer; EntriesCount: Integer; Table: tdynamicarray);
        procedure WriteLinkingSubsection(wlst: TWasmLinkingSubsectionType);
        procedure DoRelocations;
        procedure WriteRelocations;
        function FindFunctionSymbol(Symbol: TWasmObjSymbol): TWasmObjSymbol;
      protected
        function writeData(Data:TObjData):boolean;override;
      public
        constructor create(AWriter:TObjectWriter);override;
        destructor destroy;override;
      end;

      { TWasmObjInput }

      TWasmObjInput = class(TObjInput)
      private
        FFuncTypes: array of TWasmFuncType;
      public
        constructor create;override;
        destructor Destroy;override;
        class function CanReadObjData(AReader:TObjectreader):boolean;override;
        function ReadObjData(AReader:TObjectreader;out ObjData:TObjData):boolean;override;
      end;

      { TWasmExeOutput }

      TWasmExeOutput = class(TExeOutput)
      private
        const
          DataSections: array [1..3] of string = (
            '.rodata',
            '.data',
            'fpc.resources');
        WasmPageSize = 65536;

        type
          TCustomSectionNameMapEntry = record
            idx: UInt32;
            name: string;
          end;
          TCustomSectionNameMap = array of TCustomSectionNameMapEntry;
      private
        FImports: TFPHashObjectList;
        FFuncTypes: TWasmFuncTypeTable;

        FFunctionImports: array of record
          ModName: ansistring;
          Name: ansistring;
          TypeIdx: uint32;
        end;

        FTagImports: array of record
        end;

        FIndirectFunctionTable: array of record
          FuncIdx: Integer;
        end;

        FRelocationPass: Integer;
        FWasmSections: array [TWasmSectionID] of tdynamicarray;
        FWasmCustomSections: array [TWasmCustomSectionType] of tdynamicarray;
        FWasmNameSubsections: array [TWasmNameSubsectionType] of tdynamicarray;
        FStackPointerSym: TWasmObjSymbol;
        FTlsBaseSym: TWasmObjSymbol;
        FTlsSizeSym: TWasmObjSymbol;
        FTlsAlignSym: TWasmObjSymbol;
        FInitTlsFunctionSym: TWasmObjSymbol;
        FInitSharedMemoryFunctionSym: TWasmObjSymbol;
        FMinMemoryPages,
        FMaxMemoryPages: Integer;
        { use for the Name section }
        FFunctionNameMap: TCustomSectionNameMap;
        FGlobalNameMap: TCustomSectionNameMap;
        FDataNameMap: TCustomSectionNameMap;
        FTagNameMap: TCustomSectionNameMap;
        procedure AddToNameMap(var nm: TCustomSectionNameMap; aidx: UInt32; const aname: string);
        procedure AddToFunctionNameMap(aidx: UInt32; const aname: string);
        procedure AddToGlobalNameMap(aidx: UInt32; const aname: string);
        procedure AddToDataNameMap(aidx: UInt32; const aname: string);
        procedure AddToTagNameMap(aidx: UInt32; const aname: string);
        procedure WriteWasmSection(wsid: TWasmSectionID);
        procedure WriteWasmSectionIfNotEmpty(wsid: TWasmSectionID);
        procedure WriteWasmCustomSection(wcst: TWasmCustomSectionType);
        procedure PrepareImports;
        procedure PrepareFunctions;
        procedure PrepareTags;
        function AddOrGetIndirectFunctionTableIndex(FuncIdx: Integer): integer;
        procedure SetStackPointer;
        procedure SetTlsSizeAlignAndBase;
        procedure SetThreadVarGlobalsInitValues;
        procedure GenerateCode_InitTls;
        procedure GenerateCode_InitSharedMemory;
        procedure GenerateCode_InvokeHelper;
        procedure WriteExeSectionToDynArray(exesec: TExeSection; dynarr: tdynamicarray);
        procedure WriteMap_TypeSection;
        procedure WriteMap_IndirectFunctionTable;
      protected
        function writeData:boolean;override;
        procedure DoRelocationFixup(objsec:TObjSection);override;
      public
        constructor create;override;
        destructor destroy;override;
        procedure GenerateLibraryImports(ImportLibraryList:TFPHashObjectList);override;
        procedure AfterUnusedSectionRemoval;override;
        procedure MemPos_ExeSection(const aname:string);override;
        procedure Load_Symbol(const aname: string);override;
      end;

      { TWasmAssembler }

      TWasmAssembler = class(tinternalassembler)
        constructor create(info: pasminfo; smart:boolean);override;
      end;

implementation

    uses
      cutils,verbose,version,globals,fmodule,ogmap;

    const
      StackPointerSymStr='__stack_pointer';

    procedure WriteUleb5(d: tdynamicarray; v: uint64);
      var
        b: byte;
        i: Integer;
      begin
        for i:=1 to 5 do
          begin
            b:=byte(v) and 127;
            v:=v shr 7;
            if i<>5 then
              b:=b or 128;
            d.write(b,1);
          end;
      end;

    procedure WriteUleb5(d: tobjsection; v: uint64);
      var
        b: byte;
        i: Integer;
      begin
        for i:=1 to 5 do
          begin
            b:=byte(v) and 127;
            v:=v shr 7;
            if i<>5 then
              b:=b or 128;
            d.write(b,1);
          end;
      end;

    procedure WriteSleb5(d: tdynamicarray; v: int64);
      var
        b: byte;
        i: Integer;
      begin
        for i:=1 to 5 do
          begin
            b:=byte(v) and 127;
            v:=SarInt64(v,7);
            if i<>5 then
              b:=b or 128;
            d.write(b,1);
          end;
      end;

    procedure WriteSleb5(d: tobjsection; v: int64);
      var
        b: byte;
        i: Integer;
      begin
        for i:=1 to 5 do
          begin
            b:=byte(v) and 127;
            v:=SarInt64(v,7);
            if i<>5 then
              b:=b or 128;
            d.write(b,1);
          end;
      end;
    procedure WriteUleb(d: tdynamicarray; v: uint64);
      var
        b: byte;
      begin
        repeat
          b:=byte(v) and 127;
          v:=v shr 7;
          if v<>0 then
            b:=b or 128;
          d.write(b,1);
        until v=0;
      end;

    procedure WriteUleb(d: tobjsection; v: uint64);
      var
        b: byte;
      begin
        repeat
          b:=byte(v) and 127;
          v:=v shr 7;
          if v<>0 then
            b:=b or 128;
          d.write(b,1);
        until v=0;
      end;

    procedure WriteUleb(w: TObjectWriter; v: uint64);
      var
        b: byte;
      begin
        repeat
          b:=byte(v) and 127;
          v:=v shr 7;
          if v<>0 then
            b:=b or 128;
          w.write(b,1);
        until v=0;
      end;

    procedure WriteSleb(d: tdynamicarray; v: int64);
      var
        b: byte;
        Done: Boolean=false;
      begin
        repeat
          b:=byte(v) and 127;
          v:=SarInt64(v,7);
          if ((v=0) and ((b and 64)=0)) or ((v=-1) and ((b and 64)<>0)) then
            Done:=true
          else
            b:=b or 128;
          d.write(b,1);
        until Done;
      end;

    procedure WriteSleb(d: tobjsection; v: int64);
      var
        b: byte;
        Done: Boolean=false;
      begin
        repeat
          b:=byte(v) and 127;
          v:=SarInt64(v,7);
          if ((v=0) and ((b and 64)=0)) or ((v=-1) and ((b and 64)<>0)) then
            Done:=true
          else
            b:=b or 128;
          d.write(b,1);
        until Done;
      end;

    function UlebEncodingSize(v: uint64): Integer;
      var
        b: byte;
      begin
        Result:=0;
        repeat
          b:=byte(v) and 127;
          v:=v shr 7;
          if v<>0 then
            b:=b or 128;
          Inc(Result);
        until v=0;
      end;

{$ifdef FPC_LITTLE_ENDIAN}
    procedure WriteF32LE(d: tdynamicarray; v: Single);
      begin
        d.write(v,4);
      end;

    procedure WriteF64LE(d: tdynamicarray; v: Double);
      begin
        d.write(v,8);
      end;
{$else FPC_LITTLE_ENDIAN}
    procedure WriteF32LE(d: tdynamicarray; v: Single);
      var
        tmpI: UInt32;
      begin
        Move(v,tmpI,4);
        tmpI:=SwapEndian(tmpI);
        d.write(tmpI,4);
      end;

    procedure WriteF64LE(d: tdynamicarray; v: Double);
      var
        tmpI: UInt64;
      begin
        Move(v,tmpI,8);
        tmpI:=SwapEndian(tmpI);
        d.write(tmpI,8);
      end;
{$endif FPC_LITTLE_ENDIAN}

    procedure WriteByte(d: tdynamicarray; b: byte);
      begin
        d.write(b,1);
      end;

    procedure WriteName(d: tdynamicarray; const s: string);
      begin
        WriteUleb(d,Length(s));
        d.writestr(s);
      end;

    procedure WriteWasmBasicType(dest: tdynamicarray; wbt: TWasmBasicType);
      begin
        WriteByte(dest,encode_wasm_basic_type(wbt));
      end;

    procedure WriteWasmResultType(dest: tdynamicarray; wrt: TWasmResultType);
      var
        i: Integer;
      begin
        WriteUleb(dest,Length(wrt));
        for i:=low(wrt) to high(wrt) do
          WriteWasmBasicType(dest,wrt[i]);
      end;

    function ReadUleb(d: tdynamicarray): uint64;
      var
        b: byte;
        shift:integer;
      begin
        b:=0;
        result:=0;
        shift:=0;
        repeat
          d.read(b,1);
          result:=result or (uint64(b and 127) shl shift);
          inc(shift,7);
        until (b and 128)=0;
      end;

    function ReadSleb(d: tdynamicarray): int64;
      var
        b: byte;
        shift:integer;
      begin
        b:=0;
        result:=0;
        shift:=0;
        repeat
          d.read(b,1);
          result:=result or (uint64(b and 127) shl shift);
          inc(shift,7);
        until (b and 128)=0;
{$ifopt Q+}
{$define overflowon}
{$Q-}
{$endif}
{$ifopt R+}
{$define rangeon}
{$R-}
{$endif}
        if (b and 64)<>0 then
          result:=result or (high(uint64) shl shift);
      end;
{$ifdef overflowon}
{$Q+}
{$undef overflowon}
{$endif}
{$ifdef rangeon}
{$R+}
{$undef rangeon}
{$endif}

    procedure AddSleb5(d: tdynamicarray; v: int64);
      var
        q: Int64;
        p: LongWord;
      begin
        p:=d.Pos;
        q:=ReadSleb(d);
        q:=q+v;
        d.seek(p);
        WriteSleb5(d,q);
      end;

    procedure AddUleb5(d: tdynamicarray; v: int64);
      var
        q: UInt64;
        p: LongWord;
      begin
        p:=d.Pos;
        q:=ReadUleb(d);
        q:=q+v;
        d.seek(p);
        WriteUleb5(d,q);
      end;

    procedure AddInt32(d: tdynamicarray; v: int32);
      var
        q: int32;
        p: LongWord;
      begin
        p:=d.Pos;

        d.read(q,4);
{$ifdef FPC_BIG_ENDIAN}
        q:=SwapEndian(q);
{$endif FPC_BIG_ENDIAN}
        q:=q+v;
{$ifdef FPC_BIG_ENDIAN}
        q:=SwapEndian(q);
{$endif FPC_BIG_ENDIAN}

        d.seek(p);
        d.write(q,4);
      end;

    procedure CopyDynamicArray(src, dest: tdynamicarray; size: QWord);
      var
        buf: array [0..4095] of byte;
        bs: Integer;
      begin
        while size>0 do
          begin
            if size<SizeOf(buf) then
              bs:=Integer(size)
            else
              bs:=SizeOf(buf);
            src.read(buf,bs);
            dest.write(buf,bs);
            dec(size,bs);
          end;
      end;

    procedure WriteZeros(dest: tdynamicarray; size: QWord);
      var
        buf : array[0..1023] of byte;
        bs: Integer;
      begin
        fillchar(buf,sizeof(buf),0);
        while size>0 do
          begin
            if size<SizeOf(buf) then
              bs:=Integer(size)
            else
              bs:=SizeOf(buf);
            dest.write(buf,bs);
            dec(size,bs);
          end;
      end;


{****************************************************************************
                         TWasmObjSymbolLinkingData
****************************************************************************}

    constructor TWasmObjSymbolLinkingData.Create;
      begin
        ExeFunctionIndex:=-1;
        ExeIndirectFunctionTableIndex:=-1;
        ExeTypeIndex:=-1;
        ExeTagIndex:=-1;
      end;

    destructor TWasmObjSymbolLinkingData.Destroy;
      begin
        FuncType.Free;
        inherited Destroy;
      end;

{****************************************************************************
                             TWasmObjRelocation
****************************************************************************}

    constructor TWasmObjRelocation.CreateTypeIndex(ADataOffset: TObjSectionOfs; ATypeIndex: Integer);
      begin
        DataOffset:=ADataOffset;
        Symbol:=nil;
        OrgSize:=0;
        Group:=nil;
        ObjSection:=nil;
        ftype:=ord(RELOC_TYPE_INDEX_LEB);
        TypeIndex:=ATypeIndex;
        FuncType:=nil;
        ExeTypeIndex:=-1;
      end;

    constructor TWasmObjRelocation.CreateFuncType(ADataOffset: TObjSectionOfs; AFuncType: TWasmFuncType);
      begin
        DataOffset:=ADataOffset;
        Symbol:=nil;
        OrgSize:=0;
        Group:=nil;
        ObjSection:=nil;
        ftype:=ord(RELOC_TYPE_INDEX_LEB);
        TypeIndex:=-1;
        ExeTypeIndex:=-1;
        FuncType:=TWasmFuncType.Create(AFuncType);
      end;

    destructor TWasmObjRelocation.Destroy;
      begin
        FuncType.Free;
        inherited Destroy;
      end;

{****************************************************************************
                               TWasmObjSymbol
****************************************************************************}

    constructor TWasmObjSymbol.create(AList: TFPHashObjectList; const AName: string);
      begin
        inherited create(AList,AName);
        FuncIndex:=-1;
        SymbolIndex:=-1;
        GlobalIndex:=-1;
        TagIndex:=-1;
        AliasOf:='';
        ExtraData:=nil;
        LinkingData:=TWasmObjSymbolLinkingData.Create;
      end;

    destructor TWasmObjSymbol.Destroy;
      begin
        LinkingData.Free;
        inherited Destroy;
      end;

    function TWasmObjSymbol.IsAlias: Boolean;
      begin
        result:=AliasOf<>'';
      end;

{****************************************************************************
                              TWasmObjSymbolExtraData
****************************************************************************}

    constructor TWasmObjSymbolExtraData.Create(HashObjectList: TFPHashObjectList; const s: TSymStr);
      begin
        EncodedLocals:=nil;
        inherited Create(HashObjectList,s);
        TypeIdx:=-1;
        ExceptionTagTypeIdx:=-1;
      end;

    destructor TWasmObjSymbolExtraData.Destroy;
      begin
        EncodedLocals.Free;
        inherited Destroy;
      end;

    procedure TWasmObjSymbolExtraData.AddLocals(alocals: TWasmLocalsDynArray);
      var
        i,
        rle_entries,
        cnt: Integer;
        lasttype: TWasmBasicType;
      begin
        Locals:=alocals;
        if Assigned(EncodedLocals) then
          internalerror(2024081502);
        EncodedLocals:=tdynamicarray.Create(64);
        if Length(Locals)=0 then
          begin
            WriteUleb(EncodedLocals,0);
            exit;
          end;

        rle_entries:=1;
        for i:=low(Locals)+1 to high(Locals) do
          if Locals[i]<>Locals[i-1] then
            inc(rle_entries);

        WriteUleb(EncodedLocals,rle_entries);
        lasttype:=Locals[Low(Locals)];
        cnt:=1;
        for i:=low(Locals)+1 to high(Locals) do
          if Locals[i]=Locals[i-1] then
            inc(cnt)
          else
            begin
              WriteUleb(EncodedLocals,cnt);
              WriteWasmBasicType(EncodedLocals,lasttype);
              lasttype:=Locals[i];
              cnt:=1;
            end;
        WriteUleb(EncodedLocals,cnt);
        WriteWasmBasicType(EncodedLocals,lasttype);
      end;

{****************************************************************************
                              TWasmObjSection
****************************************************************************}

    constructor TWasmObjSection.create(AList: TFPHashObjectList; const Aname: string; Aalign: longint; Aoptions: TObjSectionOptions);
      begin
        inherited create(AList, Aname, Aalign, Aoptions);
        SegIdx:=-1;
        SegSymIdx:=-1;
        CustomSectionIdx:=-1;
        MainFuncSymbol:=nil;
      end;

    function TWasmObjSection.IsCode: Boolean;
      const
        CodePrefix = '.text';
      begin
        result:=(Length(Name)>=Length(CodePrefix)) and
          (Copy(Name,1,Length(CodePrefix))=CodePrefix);
      end;

    function TWasmObjSection.IsData: Boolean;
      begin
        result:=not (IsCode or IsDebug);
      end;

    function TWasmObjSection.IsDebug: Boolean;
      const
        DebugPrefix = '.debug';
      begin
        result:=(Length(Name)>=Length(DebugPrefix)) and
          (Copy(Name,1,Length(DebugPrefix))=DebugPrefix);
      end;

{****************************************************************************
                             TWasmFuncTypeTable
****************************************************************************}

    function TWasmFuncTypeTable.GetCount: Integer;
      begin
        Result:=Length(FFuncTypes);
      end;

    function TWasmFuncTypeTable.GetItem(Index: Integer): TWasmFuncType;
      begin
        if (Index<Low(FFuncTypes)) or (Index>High(FFuncTypes)) then
          internalerror(2023123101);
        Result:=FFuncTypes[Index];
      end;

    destructor TWasmFuncTypeTable.Destroy;
      var
        i: Integer;
      begin
        for i:=low(FFuncTypes) to high(FFuncTypes) do
          begin
            FFuncTypes[i].free;
            FFuncTypes[i]:=nil;
          end;
      end;

    function TWasmFuncTypeTable.AddOrGetFuncType(wft: TWasmFuncType): integer;
      var
        i: Integer;
      begin
        for i:=low(FFuncTypes) to high(FFuncTypes) do
          if wft.Equals(FFuncTypes[i]) then
            exit(i);

        result:=Length(FFuncTypes);
        SetLength(FFuncTypes,result+1);
        FFuncTypes[result]:=TWasmFuncType.Create(wft);
      end;

    procedure TWasmFuncTypeTable.WriteTo(d: tdynamicarray);
      var
        types_count, i: Integer;
      begin
        types_count:=Count;
        WriteUleb(d,types_count);
        for i:=0 to types_count-1 do
          with Items[i] do
            begin
              WriteByte(d,$60);
              WriteWasmResultType(d,params);
              WriteWasmResultType(d,results);
            end;
      end;

{****************************************************************************
                                TWasmObjData
****************************************************************************}

    function TWasmObjData.is_smart_section(atype: TAsmSectiontype): boolean;
      begin
        { For bss we need to set some flags that are target dependent,
          it is easier to disable it for smartlinking. It doesn't take up
          filespace }
        result:=not(target_info.system in systems_darwin) and
           create_smartlink_sections and
           (atype<>sec_toc) and
           (atype<>sec_user) and
           { on embedded systems every byte counts, so smartlink bss too }
           ((atype<>sec_bss) or (target_info.system in (systems_embedded+systems_freertos)));
      end;

    function TWasmObjData.sectionname_gas(atype: TAsmSectiontype;
        const aname: string; aorder: TAsmSectionOrder): string;
      const
        secnames : array[TAsmSectiontype] of string[length('__DATA, __datacoal_nt,coalesced')] = ('','',
          '.text',
          '.data',
{ why doesn't .rodata work? (FK) }
{ sometimes we have to create a data.rel.ro instead of .rodata, e.g. for  }
{ vtables (and anything else containing relocations), otherwise those are }
{ not relocated properly on e.g. linux/ppc64. g++ generates there for a   }
{ vtable for a class called Window:                                       }
{ .section .data.rel.ro._ZTV6Window,"awG",@progbits,_ZTV6Window,comdat    }
{ TODO: .data.ro not yet working}
{$if defined(arm) or defined(riscv64) or defined(powerpc)}
          '.rodata',
{$else defined(arm) or defined(riscv64) or defined(powerpc)}
          '.data',
{$endif defined(arm) or defined(riscv64) or defined(powerpc)}
          '.rodata',
          '.bss',
          '.tbss',
          '.pdata',
          '', { stubs }
          '__DATA,__nl_symbol_ptr',
          '__DATA,__la_symbol_ptr',
          '__DATA,__mod_init_func',
          '__DATA,__mod_term_func',
          '.stab',
          '.stabstr',
          '.idata$2','.idata$4','.idata$5','.idata$6','.idata$7','.edata',
          '.eh_frame',
          '.debug_frame','.debug_info','.debug_line','.debug_abbrev','.debug_aranges','.debug_ranges','.debug_loc','.debug_loclists',
          '.fpc',
          '.toc',
          '.init',
          '.fini',
          '.objc_class',
          '.objc_meta_class',
          '.objc_cat_cls_meth',
          '.objc_cat_inst_meth',
          '.objc_protocol',
          '.objc_string_object',
          '.objc_cls_meth',
          '.objc_inst_meth',
          '.objc_cls_refs',
          '.objc_message_refs',
          '.objc_symbols',
          '.objc_category',
          '.objc_class_vars',
          '.objc_instance_vars',
          '.objc_module_info',
          '.objc_class_names',
          '.objc_meth_var_types',
          '.objc_meth_var_names',
          '.objc_selector_strs',
          '.objc_protocol_ext',
          '.objc_class_ext',
          '.objc_property',
          '.objc_image_info',
          '.objc_cstring_object',
          '.objc_sel_fixup',
          '__DATA,__objc_data',
          '__DATA,__objc_const',
          '.objc_superrefs',
          '__DATA, __datacoal_nt,coalesced',
          '.objc_classlist',
          '.objc_nlclasslist',
          '.objc_catlist',
          '.obcj_nlcatlist',
          '.objc_protolist',
          '.stack',
          '.heap',
          '.gcc_except_table',
          '.ARM.attributes'
        );
      var
        sep     : string[3];
        secname : string;
      begin
        secname:=secnames[atype];

        if (atype=sec_fpc) and (Copy(aname,1,3)='res') then
          begin
            result:=secname+'.'+aname;
            exit;
          end;

        { go32v2 stub only loads .text and .data sections, and allocates space for .bss.
          Thus, data which normally goes into .rodata and .rodata_norel sections must
          end up in .data section }
        if (atype in [sec_rodata,sec_rodata_norel]) and
          (target_info.system in [system_i386_go32v2,system_m68k_palmos]) then
          secname:='.data';

        { Windows correctly handles reallocations in readonly sections }
        if (atype=sec_rodata) and
          (target_info.system in systems_all_windows+systems_nativent-[system_i8086_win16]) then
          secname:='.rodata';

        { section type user gives the user full controll on the section name }
        if atype=sec_user then
          secname:=aname;

        if is_smart_section(atype) and (aname<>'') then
          begin
            case aorder of
              secorder_begin :
                sep:='.b_';
              secorder_end :
                sep:='.z_';
              else
                sep:='.n_';
            end;
            result:=secname+sep+aname
          end
        else
          result:=secname;
      end;

    constructor TWasmObjData.create(const n: string);
      begin
        inherited;
        CObjSection:=TWasmObjSection;
        CObjSymbol:=TWasmObjSymbol;
        FObjSymbolsExtraDataList:=TFPHashObjectList.Create;
        FFuncTypes:=TWasmFuncTypeTable.Create;
      end;

    destructor TWasmObjData.destroy;
      var
        i: Integer;
      begin
        FObjSymbolsExtraDataList.Free;
        FFuncTypes.Free;
        inherited destroy;
      end;

    function TWasmObjData.sectionname(atype: TAsmSectiontype;
        const aname: string; aorder: TAsmSectionOrder): string;
      begin
        if (atype=sec_fpc) or
           ((atype=sec_threadvar) and not (ts_wasm_threads in current_settings.targetswitches)) then
          atype:=sec_data;
        Result:=sectionname_gas(atype, aname, aorder);
      end;

    procedure TWasmObjData.writeReloc(Data: TRelocDataInt; len: aword;
        p: TObjSymbol; Reloctype: TObjRelocationType);
      const
        leb_zero: array[0..4] of byte=($80,$80,$80,$80,$00);
      var
        objreloc: TWasmObjRelocation;
      begin
        if CurrObjSec=nil then
          internalerror(200403072);
        { workaround crash, when generating debug info for threadvars, when multithreading is turned off.
          todo: ensure the debug info for threadvars is actually correct, once we've got WebAssembly debug info working in general }
        if (Reloctype=RELOC_DTPOFF) and not (ts_wasm_threads in current_settings.targetswitches) then
          Reloctype:=RELOC_ABSOLUTE;
        objreloc:=nil;
        case Reloctype of
          RELOC_FUNCTION_INDEX_LEB:
            begin
              if Data<>0 then
                internalerror(2021092502);
              if len<>5 then
                internalerror(2021092503);
              if not assigned(p) then
                internalerror(2021092504);
              objreloc:=TWasmObjRelocation.CreateSymbol(CurrObjSec.Size,p,Reloctype);
              CurrObjSec.ObjRelocations.Add(objreloc);
              writebytes(leb_zero,5);
            end;
          RELOC_MEMORY_ADDR_LEB,
          RELOC_MEMORY_ADDR_OR_TABLE_INDEX_SLEB:
            begin
              if (Reloctype=RELOC_MEMORY_ADDR_LEB) and (Data<0) then
                internalerror(2021092602);
              if len<>5 then
                internalerror(2021092503);
              if not assigned(p) then
                internalerror(2021092504);
              objreloc:=TWasmObjRelocation.CreateSymbol(CurrObjSec.Size,p,Reloctype);
              objreloc.Addend:=Data;
              CurrObjSec.ObjRelocations.Add(objreloc);
              if RelocType=RELOC_MEMORY_ADDR_LEB then
                WriteUleb5(CurrObjSec,Data)
              else
                WriteSleb5(CurrObjSec,Data);
            end;
          RELOC_ABSOLUTE:
            begin
              if len<>4 then
                internalerror(2021092607);
              if not assigned(p) then
                internalerror(2021092608);
              if (p.objsection<>nil) and TWasmObjSection(p.objsection).IsDebug and
                 (p.bind<>AB_COMMON) and (p.bind<>AB_EXTERNAL) then
                begin
                  objreloc:=TWasmObjRelocation.CreateSection(CurrObjSec.Size,p.objsection,RELOC_ABSOLUTE);
                  objreloc.Addend:=Data+p.Address;
                  CurrObjSec.ObjRelocations.Add(objreloc);
                  {inc(data,p.address);}
                  data:=0;
                  Data:=NtoLE(Data);
                  writebytes(Data,4);
                end
              else
                begin
                  objreloc:=TWasmObjRelocation.CreateSymbol(CurrObjSec.Size,p,Reloctype);
                  objreloc.Addend:=Data;
                  CurrObjSec.ObjRelocations.Add(objreloc);
                  Data:=NtoLE(Data);
                  writebytes(Data,4);
                end;
            end;
          RELOC_TYPE_INDEX_LEB:
            begin
              if len<>5 then
                internalerror(2021092612);
              if assigned(p) then
                internalerror(2021092613);
              objreloc:=TWasmObjRelocation.CreateTypeIndex(CurrObjSec.Size,Data);
              CurrObjSec.ObjRelocations.Add(objreloc);
              WriteUleb5(CurrObjSec,Data);
            end;
          RELOC_GLOBAL_INDEX_LEB:
            begin
              if len<>5 then
                internalerror(2021092701);
              if Data<>0 then
                internalerror(2021092702);
              if not assigned(p) then
                internalerror(2021092703);
              objreloc:=TWasmObjRelocation.CreateSymbol(CurrObjSec.Size,p,Reloctype);
              CurrObjSec.ObjRelocations.Add(objreloc);
              WriteUleb5(CurrObjSec,0);
            end;
          RELOC_TAG_INDEX_LEB:
            begin
              if len<>5 then
                internalerror(2021092712);
              if Data<>0 then
                internalerror(2021092713);
              if not assigned(p) then
                internalerror(2021092714);
              objreloc:=TWasmObjRelocation.CreateSymbol(CurrObjSec.Size,p,Reloctype);
              CurrObjSec.ObjRelocations.Add(objreloc);
              WriteSleb5(CurrObjSec,0);
            end;
          else
            internalerror(2021092501);
        end;
      end;

    function TWasmObjData.AddOrCreateObjSymbolExtraData(const symname: TSymStr): TWasmObjSymbolExtraData;
      begin
        result:=TWasmObjSymbolExtraData(FObjSymbolsExtraDataList.Find(symname));
        if not assigned(result) then
          result:=TWasmObjSymbolExtraData.Create(FObjSymbolsExtraDataList,symname);
      end;

    function TWasmObjData.globalref(asmsym: TAsmSymbol): TObjSymbol;
      begin
        if assigned(asmsym) then
          begin
            if (asmsym.typ<>AT_WASM_GLOBAL) and (asmsym.typ<>AT_TLS) then
              internalerror(2021092706);
            result:=symbolref(asmsym);
            result.typ:=asmsym.typ;
          end
        else
          result:=nil;
      end;

    function TWasmObjData.ExceptionTagRef(asmsym: TAsmSymbol): TObjSymbol;
      begin
        if assigned(asmsym) then
          begin
            if asmsym.typ<>AT_WASM_EXCEPTION_TAG then
              internalerror(2021092707);
            result:=symbolref(asmsym);
            result.typ:=AT_WASM_EXCEPTION_TAG;
          end
        else
          result:=nil;
      end;

    procedure TWasmObjData.DeclareGlobalType(gt: tai_globaltype);
      var
        ObjSymExtraData: TWasmObjSymbolExtraData;
        ObjSym: TObjSymbol;
      begin
        if not gt.is_external then
          begin
            ObjSym:=symboldefine(gt.sym);
            ObjSym.typ:=AT_WASM_GLOBAL;
          end;
        ObjSymExtraData:=AddOrCreateObjSymbolExtraData(gt.globalname);
        ObjSymExtraData.GlobalType:=gt.gtype;
        ObjSymExtraData.GlobalIsImmutable:=gt.immutable;
      end;

    procedure TWasmObjData.DeclareFuncType_Pass0(ft: tai_functype);
      var
        i: Integer;
        ObjSymExtraData: TWasmObjSymbolExtraData;
      begin
        FLastFuncName:=ft.funcname;
        i:=FFuncTypes.AddOrGetFuncType(ft.functype);
        ObjSymExtraData:=AddOrCreateObjSymbolExtraData(ft.funcname);
        ObjSymExtraData.TypeIdx:=i;
      end;

    procedure TWasmObjData.DeclareFuncType_Pass1(ft: tai_functype);
      begin
        FLastFuncName:=ft.funcname;
      end;

    procedure TWasmObjData.DeclareFuncType_Pass2(ft: tai_functype);
      begin
        FLastFuncName:=ft.funcname;
      end;

    procedure TWasmObjData.DeclareTagType(tt: tai_tagtype);
      var
        ObjSymExtraData: TWasmObjSymbolExtraData;
        ft: TWasmFuncType;
        i: Integer;
      begin
        ObjSymExtraData:=AddOrCreateObjSymbolExtraData(tt.tagname);
        ft:=TWasmFuncType.Create([],tt.params);
        i:=FFuncTypes.AddOrGetFuncType(ft);
        ft.free;
        ObjSymExtraData.ExceptionTagTypeIdx:=i;
      end;

    procedure TWasmObjData.DeclareExportName(en: tai_export_name);
      var
        ObjSymExtraData: TWasmObjSymbolExtraData;
      begin
        ObjSymExtraData:=AddOrCreateObjSymbolExtraData(en.intname);
        ObjSymExtraData.ExportName:=en.extname;
      end;

    procedure TWasmObjData.DeclareImportModule(aim: tai_import_module);
      var
        ObjSymExtraData: TWasmObjSymbolExtraData;
      begin
        ObjSymExtraData:=AddOrCreateObjSymbolExtraData(aim.symname);
        ObjSymExtraData.ImportModule:=aim.importmodule;
      end;

    procedure TWasmObjData.DeclareImportName(ain: tai_import_name);
      var
        ObjSymExtraData: TWasmObjSymbolExtraData;
      begin
        ObjSymExtraData:=AddOrCreateObjSymbolExtraData(ain.symname);
        ObjSymExtraData.ImportName:=ain.importname;
      end;

    procedure TWasmObjData.DeclareLocals_Pass0(al: tai_local);
      var
        ObjSymExtraData: TWasmObjSymbolExtraData;
      begin
        ObjSymExtraData:=TWasmObjSymbolExtraData(FObjSymbolsExtraDataList.Find(FLastFuncName));
        ObjSymExtraData.AddLocals(al.locals);
        alloc(ObjSymExtraData.EncodedLocals.size);
      end;

    procedure TWasmObjData.DeclareLocals_Pass1(al: tai_local);
      var
        ObjSymExtraData: TWasmObjSymbolExtraData;
      begin
        ObjSymExtraData:=TWasmObjSymbolExtraData(FObjSymbolsExtraDataList.Find(FLastFuncName));
        alloc(ObjSymExtraData.EncodedLocals.size);
      end;

    procedure TWasmObjData.WriteLocals_Pass2(al: tai_local);
      var
        ObjSymExtraData: TWasmObjSymbolExtraData;
        d: tdynamicarray;
        buf: array [0..4095] of byte;
        bs,size: Integer;
      begin
        ObjSymExtraData:=TWasmObjSymbolExtraData(FObjSymbolsExtraDataList.Find(FLastFuncName));
        d:=ObjSymExtraData.EncodedLocals;
        d.seek(0);
        size:=d.size;
        while size>0 do
          begin
            if size<SizeOf(buf) then
              bs:=Integer(size)
            else
              bs:=SizeOf(buf);
            d.read(buf,bs);
            writebytes(buf,bs);
            dec(size,bs);
          end;
      end;

    procedure TWasmObjData.symbolpairdefine(akind: TSymbolPairKind; const asym, avalue: string);
      var
        valsym: TObjSymbol;
        aliassym: TWasmObjSymbol;
      begin
        valsym:=CreateSymbol(avalue);
        aliassym:=TWasmObjSymbol(symboldefine(asym,valsym.bind,valsym.typ));
        aliassym.AliasOf:=valsym.Name;
      end;

{****************************************************************************
                               TWasmObjOutput
****************************************************************************}

    procedure TWasmObjOutput.WriteWasmSection(wsid: TWasmSectionID);
      var
        b: byte;
      begin
        b:=ord(wsid);
        Writer.write(b,1);
        WriteUleb(Writer,FWasmSections[wsid].size);
        Writer.writearray(FWasmSections[wsid]);
      end;

    procedure TWasmObjOutput.WriteWasmCustomSection(wcst: TWasmCustomSectionType);
      var
        b: byte;
      begin
        b:=0;
        Writer.write(b,1);
        WriteUleb(Writer,FWasmCustomSections[wcst].size);
        Writer.writearray(FWasmCustomSections[wcst]);
      end;

    function TWasmObjOutput.IsExternalFunction(sym: TObjSymbol): Boolean;
      var
        ExtraData: TWasmObjSymbolExtraData;
      begin
        if sym.bind=AB_EXTERNAL then
          begin
            ExtraData:=TWasmObjSymbolExtraData(TWasmObjData(sym.ObjData).FObjSymbolsExtraDataList.Find(sym.Name));
            result:=(ExtraData<>nil) and (ExtraData.TypeIdx<>-1);
          end
        else
          result:=false;

      end;

    function TWasmObjOutput.IsExportedFunction(sym: TWasmObjSymbol): Boolean;
      var
        ExtraData: TWasmObjSymbolExtraData;
      begin
        if (sym.typ=AT_FUNCTION) and not sym.IsAlias then
          begin
            ExtraData:=TWasmObjSymbolExtraData(TWasmObjData(sym.ObjData).FObjSymbolsExtraDataList.Find(sym.Name));
            result:=(ExtraData<>nil) and (ExtraData.ExportName<>'');
          end
        else
          result:=false;
      end;

    procedure TWasmObjOutput.WriteFunctionCode(dest: tdynamicarray; objsym: TObjSymbol);
      var
        ObjSymExtraData: TWasmObjSymbolExtraData;
        ObjSection: TWasmObjSection;
        codelen: QWord;
      begin
        ObjSymExtraData:=TWasmObjSymbolExtraData(FData.FObjSymbolsExtraDataList.Find(objsym.Name));
        ObjSection:=TWasmObjSection(objsym.objsection);
        ObjSection.Data.seek(objsym.address);
        codelen:=objsym.size;

        WriteUleb(dest,codelen);
        ObjSection.FileSectionOfs:=dest.size-objsym.offset;
        CopyDynamicArray(ObjSection.Data,dest,codelen);
      end;

    procedure TWasmObjOutput.WriteSymbolTable;
      begin
        WriteUleb(FWasmLinkingSubsections[WASM_SYMBOL_TABLE],FWasmSymbolTableEntriesCount);
        FWasmSymbolTable.seek(0);
        CopyDynamicArray(FWasmSymbolTable,FWasmLinkingSubsections[WASM_SYMBOL_TABLE],FWasmSymbolTable.size);
      end;

    procedure TWasmObjOutput.WriteRelocationCodeTable(CodeSectionIndex: Integer);
      begin
        WriteUleb(FWasmCustomSections[wcstRelocCode],CodeSectionIndex);
        WriteUleb(FWasmCustomSections[wcstRelocCode],FWasmRelocationCodeTableEntriesCount);
        FWasmRelocationCodeTable.seek(0);
        CopyDynamicArray(FWasmRelocationCodeTable,FWasmCustomSections[wcstRelocCode],FWasmRelocationCodeTable.size);
      end;

    procedure TWasmObjOutput.WriteRelocationDataTable(DataSectionIndex: Integer);
      begin
        WriteUleb(FWasmCustomSections[wcstRelocData],DataSectionIndex);
        WriteUleb(FWasmCustomSections[wcstRelocData],FWasmRelocationDataTableEntriesCount);
        FWasmRelocationDataTable.seek(0);
        CopyDynamicArray(FWasmRelocationDataTable,FWasmCustomSections[wcstRelocData],FWasmRelocationDataTable.size);
      end;

    procedure TWasmObjOutput.MaybeWriteRelocationDebugTable(cst: TWasmCustomSectionType; SectionIndex: Integer; EntriesCount: Integer; Table: tdynamicarray);
      begin
        if EntriesCount>0 then
          begin
            WriteUleb(FWasmCustomSections[cst],SectionIndex);
            WriteUleb(FWasmCustomSections[cst],EntriesCount);
            Table.seek(0);
            CopyDynamicArray(Table,FWasmCustomSections[cst],Table.size);
            WriteWasmCustomSection(cst);
          end;
      end;

    procedure TWasmObjOutput.WriteLinkingSubsection(wlst: TWasmLinkingSubsectionType);
      begin
        if FWasmLinkingSubsections[wlst].size>0 then
          begin
            WriteByte(FWasmCustomSections[wcstLinking],Ord(wlst));
            WriteUleb(FWasmCustomSections[wcstLinking],FWasmLinkingSubsections[wlst].size);
            FWasmLinkingSubsections[wlst].seek(0);
            CopyDynamicArray(FWasmLinkingSubsections[wlst],FWasmCustomSections[wcstLinking],FWasmLinkingSubsections[wlst].size);
          end;
      end;

    procedure TWasmObjOutput.DoRelocations;
      var
        si, ri: Integer;
        objsec: TWasmObjSection;
        objrel: TWasmObjRelocation;
      begin
        for si:=0 to FData.ObjSectionList.Count-1 do
          begin
            objsec:=TWasmObjSection(FData.ObjSectionList[si]);
            for ri:=0 to objsec.ObjRelocations.Count-1 do
              begin
                objrel:=TWasmObjRelocation(objsec.ObjRelocations[ri]);
                case objrel.typ of
                  RELOC_FUNCTION_INDEX_LEB:
                    begin
                      if not assigned(objrel.symbol) then
                        internalerror(2021092509);
                      objsec.Data.seek(objrel.DataOffset);
                      if TWasmObjSymbol(objrel.symbol).FuncIndex<0 then
                        message1(asmw_e_illegal_unset_index,objrel.symbol.name)
                      else
                        WriteUleb5(objsec.Data,TWasmObjSymbol(objrel.symbol).FuncIndex);
                    end;
                  RELOC_MEMORY_ADDR_OR_TABLE_INDEX_SLEB:
                    begin
                      if not assigned(objrel.symbol) then
                        internalerror(2021092605);
                      if not (IsExternalFunction(objrel.symbol) or (objrel.symbol.typ=AT_FUNCTION) or (objrel.symbol.bind=AB_EXTERNAL)) then
                        begin
                          objsec.Data.seek(objrel.DataOffset);
                          AddSleb5(objsec.Data,objrel.symbol.offset+TWasmObjSection(objrel.symbol.objsection).SegOfs);
                        end;
                    end;
                  RELOC_MEMORY_ADDR_LEB:
                    begin
                      if not assigned(objrel.symbol) then
                        internalerror(2021092606);
                      if IsExternalFunction(objrel.symbol) or (objrel.symbol.typ=AT_FUNCTION) then
                        internalerror(2021092628);
                      if objrel.symbol.bind<>AB_EXTERNAL then
                        begin
                          objsec.Data.seek(objrel.DataOffset);
                          AddUleb5(objsec.Data,objrel.symbol.offset+TWasmObjSection(objrel.symbol.objsection).SegOfs);
                        end;
                    end;
                  RELOC_ABSOLUTE:
                    begin
                      if assigned(objrel.ObjSection) then
                        begin
                          { todo: should we do something here? }
                          //Writeln('todo: section relocation');
                        end
                      else if not (IsExternalFunction(objrel.symbol) or (objrel.symbol.typ=AT_FUNCTION) or (objrel.symbol.bind=AB_EXTERNAL)) then
                        begin
                          objsec.Data.seek(objrel.DataOffset);
                          AddInt32(objsec.Data,objrel.symbol.offset+TWasmObjSection(objrel.symbol.objsection).SegOfs);
                        end;
                    end;
                  RELOC_TYPE_INDEX_LEB:
                    ;
                  RELOC_GLOBAL_INDEX_LEB:
                    begin
                      if not assigned(objrel.symbol) then
                        internalerror(2021092509);
                      objsec.Data.seek(objrel.DataOffset);
                      if TWasmObjSymbol(objrel.symbol).GlobalIndex<0 then
                        message1(asmw_e_illegal_unset_index,objrel.symbol.name)
                      else
                        WriteUleb5(objsec.Data,TWasmObjSymbol(objrel.symbol).GlobalIndex);
                    end;
                  RELOC_TAG_INDEX_LEB:
                    begin
                      if not assigned(objrel.symbol) then
                        internalerror(2021092716);
                      objsec.Data.seek(objrel.DataOffset);
                      if TWasmObjSymbol(objrel.symbol).TagIndex<0 then
                        message1(asmw_e_illegal_unset_index,objrel.symbol.name)
                      else
                        WriteSleb5(objsec.Data,TWasmObjSymbol(objrel.symbol).TagIndex);
                    end;
                  else
                    internalerror(2021092510);
                end;
              end;
          end;
      end;

    procedure TWasmObjOutput.WriteRelocations;
      var
        si, ri: Integer;
        objsec: TWasmObjSection;
        objrel: TWasmObjRelocation;
        relout: tdynamicarray;
        relcount: PInteger;
        FuncSym: TWasmObjSymbol;
      begin
        for si:=0 to FData.ObjSectionList.Count-1 do
          begin
            objsec:=TWasmObjSection(FData.ObjSectionList[si]);
            if objsec.IsCode then
              begin
                relout:=FWasmRelocationCodeTable;
                relcount:=@FWasmRelocationCodeTableEntriesCount;
              end
            else if objsec.IsData then
              begin
                relout:=FWasmRelocationDataTable;
                relcount:=@FWasmRelocationDataTableEntriesCount;
              end
            else if objsec.IsDebug then
              begin
                case objsec.Name of
                  '.debug_frame':
                    begin
                      relout:=FWasmRelocationDebugFrameTable;
                      relcount:=@FWasmRelocationDebugFrameTableEntriesCount;
                    end;
                  '.debug_info':
                    begin
                      relout:=FWasmRelocationDebugInfoTable;
                      relcount:=@FWasmRelocationDebugInfoTableEntriesCount;
                    end;
                  '.debug_line':
                    begin
                      relout:=FWasmRelocationDebugLineTable;
                      relcount:=@FWasmRelocationDebugLineTableEntriesCount;
                    end;
                  '.debug_abbrev':
                    begin
                      relout:=FWasmRelocationDebugAbbrevTable;
                      relcount:=@FWasmRelocationDebugAbbrevTableEntriesCount;
                    end;
                  '.debug_aranges':
                    begin
                      relout:=FWasmRelocationDebugArangesTable;
                      relcount:=@FWasmRelocationDebugArangesTableEntriesCount;
                    end;
                  '.debug_ranges':
                    begin
                      relout:=FWasmRelocationDebugRangesTable;
                      relcount:=@FWasmRelocationDebugRangesTableEntriesCount;
                    end;
                  '.debug_str':
                    begin
                      relout:=FWasmRelocationDebugStrTable;
                      relcount:=@FWasmRelocationDebugStrTableEntriesCount;
                    end;
                  else
                    internalerror(2022071601);
                end;
              end
            else
              continue;
            for ri:=0 to objsec.ObjRelocations.Count-1 do
              begin
                objrel:=TWasmObjRelocation(objsec.ObjRelocations[ri]);
                case objrel.typ of
                  RELOC_FUNCTION_INDEX_LEB:
                    begin
                      if not assigned(objrel.symbol) then
                        internalerror(2021092508);
                      Inc(relcount^);
                      WriteByte(relout,Ord(R_WASM_FUNCTION_INDEX_LEB));
                      WriteUleb(relout,objrel.DataOffset+objsec.FileSectionOfs);
                      WriteUleb(relout,TWasmObjSymbol(objrel.symbol).SymbolIndex);
                    end;
                  RELOC_MEMORY_ADDR_LEB:
                    begin
                      if not assigned(objrel.symbol) then
                        internalerror(2021092603);
                      Inc(relcount^);
                      if IsExternalFunction(objrel.symbol) or (objrel.symbol.typ=AT_FUNCTION) then
                        internalerror(2021092628);
                      WriteByte(relout,Ord(R_WASM_MEMORY_ADDR_LEB));
                      WriteUleb(relout,objrel.DataOffset+objsec.FileSectionOfs);
                      WriteUleb(relout,TWasmObjSymbol(objrel.symbol).SymbolIndex);
                      WriteSleb(relout,objrel.Addend);  { addend to add to the address }
                    end;
                  RELOC_MEMORY_ADDR_OR_TABLE_INDEX_SLEB:
                    begin
                      if not assigned(objrel.symbol) then
                        internalerror(2021092604);
                      Inc(relcount^);
                      if IsExternalFunction(objrel.symbol) or (objrel.symbol.typ=AT_FUNCTION) then
                        begin
                          WriteByte(relout,Ord(R_WASM_TABLE_INDEX_SLEB));
                          WriteUleb(relout,objrel.DataOffset+objsec.FileSectionOfs);
                          WriteUleb(relout,TWasmObjSymbol(objrel.symbol).SymbolIndex);
                        end
                      else
                        begin
                          WriteByte(relout,Ord(R_WASM_MEMORY_ADDR_SLEB));
                          WriteUleb(relout,objrel.DataOffset+objsec.FileSectionOfs);
                          WriteUleb(relout,TWasmObjSymbol(objrel.symbol).SymbolIndex);
                          WriteSleb(relout,objrel.Addend);  { addend to add to the address }
                        end;
                    end;
                  RELOC_ABSOLUTE:
                    begin
                      // todo: figure this out, why do these exist?
                      //if assigned(objrel.symbol) and not assigned(objrel.symbol.objsection) then
                      //  Writeln('!!! ', objrel.symbol.name);
                      if assigned(objrel.objsection) then
                        begin
                          Inc(relcount^);
                          WriteByte(relout,Ord(R_WASM_SECTION_OFFSET_I32));
                          WriteUleb(relout,objrel.DataOffset+objsec.FileSectionOfs);
			  if (TWasmObjSection(objrel.objsection).SegSymIdx<0) then
                            message1(asmw_e_illegal_unset_index,objrel.objsection.name)
                          else
                            WriteUleb(relout,TWasmObjSection(objrel.objsection).SegSymIdx);
                          WriteSleb(relout,objrel.Addend);  { addend to add to the address }
                        end
                      else if (IsExternalFunction(objrel.symbol) or (objrel.symbol.typ=AT_FUNCTION)) and not objsec.IsDebug then
                        begin
                          Inc(relcount^);
                          WriteByte(relout,Ord(R_WASM_TABLE_INDEX_I32));
                          WriteUleb(relout,objrel.DataOffset+objsec.FileSectionOfs);
                          WriteUleb(relout,TWasmObjSymbol(objrel.symbol).SymbolIndex);
                        end
                      else if assigned(objrel.symbol) and assigned(objrel.symbol.objsection) and TWasmObjSection(objrel.symbol.objsection).IsCode then
                        begin
                          Inc(relcount^);
                          WriteByte(relout,Ord(R_WASM_FUNCTION_OFFSET_I32));
                          WriteUleb(relout,objrel.DataOffset+objsec.FileSectionOfs);
                          FuncSym:=FindFunctionSymbol(TWasmObjSymbol(objrel.Symbol));
			  if FuncSym.SymbolIndex<0 then
                            message1(asmw_e_illegal_unset_index,FuncSym.Name)
                          else
                            WriteUleb(relout,FuncSym.SymbolIndex);
                          WriteSleb(relout,objrel.Addend+objrel.symbol.address)  { addend to add to the address }
                        end
                      else if assigned(objrel.symbol) and (objrel.symbol.typ=AT_WASM_GLOBAL) then
                        begin
                          Inc(relcount^);
                          WriteByte(relout,Ord(R_WASM_GLOBAL_INDEX_I32));
                          WriteUleb(relout,objrel.DataOffset+objsec.FileSectionOfs);
			  if (TWasmObjSymbol(objrel.symbol).SymbolIndex<0) then
                            message1(asmw_e_illegal_unset_index,objrel.symbol.name)
                          else
                            WriteUleb(relout,TWasmObjSymbol(objrel.symbol).SymbolIndex);
                        end
                      else
                        begin
                          Inc(relcount^);
                          WriteByte(relout,Ord(R_WASM_MEMORY_ADDR_I32));
                          WriteUleb(relout,objrel.DataOffset+objsec.FileSectionOfs);
			  if (TWasmObjSymbol(objrel.symbol).SymbolIndex<0) then
                            begin
                              Writeln(objrel.symbol.objsection.Name, ' ', objrel.symbol.name, ' ', objsec.Name);
                              message1(asmw_e_illegal_unset_index,objrel.symbol.name);
                            end
                          else
                            WriteUleb(relout,TWasmObjSymbol(objrel.symbol).SymbolIndex);
                          WriteSleb(relout,objrel.Addend);  { addend to add to the address }
                        end;
                    end;
                  RELOC_TYPE_INDEX_LEB:
                    begin
                      Inc(relcount^);
                      WriteByte(relout,Ord(R_WASM_TYPE_INDEX_LEB));
                      WriteUleb(relout,objrel.DataOffset+objsec.FileSectionOfs);
                      WriteUleb(relout,objrel.TypeIndex);
                    end;
                  RELOC_GLOBAL_INDEX_LEB:
                    begin
                      if not assigned(objrel.symbol) then
                        internalerror(2021092704);
                      Inc(relcount^);
                      WriteByte(relout,Ord(R_WASM_GLOBAL_INDEX_LEB));
                      WriteUleb(relout,objrel.DataOffset+objsec.FileSectionOfs);
                      if (TWasmObjSymbol(objrel.symbol).SymbolIndex<0) then
                        message1(asmw_e_illegal_unset_index,objrel.symbol.name)
                      else
                        WriteUleb(relout,TWasmObjSymbol(objrel.symbol).SymbolIndex);
                    end;
                  RELOC_TAG_INDEX_LEB:
                    begin
                      if not assigned(objrel.symbol) then
                        internalerror(2021092717);
                      Inc(relcount^);
                      WriteByte(relout,Ord(R_WASM_TAG_INDEX_LEB));
                      WriteUleb(relout,objrel.DataOffset+objsec.FileSectionOfs);
                      if (TWasmObjSymbol(objrel.symbol).SymbolIndex<0) then
                        message1(asmw_e_illegal_unset_index,objrel.symbol.name)
                      else
                        WriteUleb(relout,TWasmObjSymbol(objrel.symbol).SymbolIndex);
                    end;
                  else
                    internalerror(2021092507);
                end;
              end;
          end;
      end;

    function TWasmObjOutput.FindFunctionSymbol(Symbol: TWasmObjSymbol): TWasmObjSymbol;
      begin
        Result:=TWasmObjSection(Symbol.objsection).MainFuncSymbol;
      end;

    function TWasmObjOutput.writeData(Data:TObjData):boolean;
      var
        section_nr: Integer;

        procedure MaybeAddDebugSectionToSymbolTable(st: TWasmCustomDebugSectionType; var debug_section_nr: Integer);
          var
            objsec: TWasmObjSection;
          begin
            objsec:=TWasmObjSection(Data.ObjSectionList.Find(WasmCustomSectionName[st]));
            if Assigned(objsec) then
              begin
                debug_section_nr:=section_nr;
                Inc(section_nr);
                objsec.SegSymIdx:=FWasmSymbolTableEntriesCount;
                objsec.CustomSectionIdx:=debug_section_nr;
                Inc(FWasmSymbolTableEntriesCount);
                WriteByte(FWasmSymbolTable,Ord(SYMTAB_SECTION));
                WriteUleb(FWasmSymbolTable,WASM_SYM_BINDING_LOCAL);
                WriteUleb(FWasmSymbolTable,debug_section_nr);
              end;
          end;

        procedure MaybeWriteDebugSection(st: TWasmCustomDebugSectionType);
          var
            objsec: TWasmObjSection;
          begin
            objsec:=TWasmObjSection(Data.ObjSectionList.Find(WasmCustomSectionName[st]));
            if Assigned(objsec) then
              begin
                if oso_Data in objsec.SecOptions then
                  begin
                    objsec.Data.seek(0);
                    CopyDynamicArray(objsec.Data,FWasmCustomSections[st],objsec.Size);
                  end
                else
                  WriteZeros(FWasmCustomSections[st],objsec.Size);
                WriteWasmCustomSection(st);
              end;
          end;

      var
        i: Integer;
        objsec: TWasmObjSection;
        segment_count: Integer = 0;
        cur_seg_ofs: qword = 0;
        imports_count, NextImportFunctionIndex, NextFunctionIndex,
        code_section_nr, data_section_nr,
        debug_abbrev_section_nr,debug_info_section_nr,debug_str_section_nr,
        debug_line_section_nr,debug_frame_section_nr,debug_aranges_section_nr,
        debug_ranges_section_nr,
        NextGlobalIndex, NextTagIndex: Integer;
        import_globals_count: Integer = 0;
        globals_count: Integer = 0;
        import_functions_count: Integer = 0;
        export_functions_count: Integer = 0;
        functions_count: Integer = 0;
        import_exception_tags_count: Integer = 0;
        exception_tags_count: Integer = 0;
        objsym, ObjSymAlias: TWasmObjSymbol;
        cust_sec: TWasmCustomSectionType;
        SegmentFlags, SymbolFlags: UInt64;
      begin
        FData:=TWasmObjData(Data);

        { each custom sections starts with its name }
        for cust_sec in TWasmCustomSectionType do
          WriteName(FWasmCustomSections[cust_sec],WasmCustomSectionName[cust_sec]);

        WriteUleb(FWasmCustomSections[wcstLinking],2);  { linking metadata version }

        for i:=0 to Data.ObjSymbolList.Count-1 do
          begin
            objsym:=TWasmObjSymbol(Data.ObjSymbolList[i]);
            if objsym.typ=AT_WASM_EXCEPTION_TAG then
              if objsym.bind=AB_EXTERNAL then
                Inc(import_exception_tags_count)
              else
                Inc(exception_tags_count);
            if objsym.typ=AT_WASM_GLOBAL then
              if objsym.bind=AB_EXTERNAL then
                Inc(import_globals_count)
              else
                Inc(globals_count);
            if (objsym.typ=AT_TLS) and (ts_wasm_threads in current_settings.targetswitches) then
              Inc(import_globals_count);
            if IsExternalFunction(objsym) then
              Inc(import_functions_count);
            if (objsym.typ=AT_FUNCTION) and not objsym.IsAlias then
              begin
                TWasmObjSection(objsym.objsection).MainFuncSymbol:=objsym;
                Inc(functions_count);
              end;
            if IsExportedFunction(objsym) then
              Inc(export_functions_count);
          end;

        FData.FFuncTypes.WriteTo(FWasmSections[wsiType]);

        for i:=0 to Data.ObjSectionList.Count-1 do
          begin
            objsec:=TWasmObjSection(Data.ObjSectionList[i]);
            if objsec.IsCode then
              objsec.SegIdx:=-1
            else if objsec.IsData then
              begin
                objsec.SegIdx:=segment_count;
                objsec.SegOfs:=cur_seg_ofs;
                Inc(segment_count);
                Inc(cur_seg_ofs,objsec.Size);
              end;
          end;

        imports_count:=2+import_globals_count+import_functions_count+import_exception_tags_count;
        WriteUleb(FWasmSections[wsiImport],imports_count);
        { import memories }
        WriteName(FWasmSections[wsiImport],'env');
        WriteName(FWasmSections[wsiImport],'__linear_memory');
        WriteByte(FWasmSections[wsiImport],$02);  { mem }
        WriteByte(FWasmSections[wsiImport],$00);  { min }
        WriteUleb(FWasmSections[wsiImport],1);    { 1 page }
        { import globals }
        NextGlobalIndex:=0;
        for i:=0 to Data.ObjSymbolList.Count-1 do
          begin
            objsym:=TWasmObjSymbol(Data.ObjSymbolList[i]);
            if (objsym.bind=AB_EXTERNAL) and (objsym.typ=AT_WASM_GLOBAL) then
              begin
                objsym.GlobalIndex:=NextGlobalIndex;
                Inc(NextGlobalIndex);
                objsym.ExtraData:=TWasmObjSymbolExtraData(FData.FObjSymbolsExtraDataList.Find(objsym.Name));
                if objsym.ExtraData.ImportModule<>'' then
                  WriteName(FWasmSections[wsiImport],objsym.ExtraData.ImportModule)
                else
                  WriteName(FWasmSections[wsiImport],'env');
                WriteName(FWasmSections[wsiImport],objsym.Name);
                WriteByte(FWasmSections[wsiImport],$03);  { global }
                WriteWasmBasicType(FWasmSections[wsiImport],objsym.ExtraData.GlobalType);
                if objsym.ExtraData.GlobalIsImmutable then
                  WriteByte(FWasmSections[wsiImport],$00)   { const }
                else
                  WriteByte(FWasmSections[wsiImport],$01);  { var }
              end
            else if (objsym.typ=AT_TLS) and (ts_wasm_threads in current_settings.targetswitches) then
              begin
                objsym.GlobalIndex:=NextGlobalIndex;
                Inc(NextGlobalIndex);
                objsym.ExtraData:=nil;
                WriteName(FWasmSections[wsiImport],'GOT.mem');
                WriteName(FWasmSections[wsiImport],objsym.Name);
                WriteByte(FWasmSections[wsiImport],$03);  { global }
                WriteWasmBasicType(FWasmSections[wsiImport],wbt_i32);  { i32 }
                WriteByte(FWasmSections[wsiImport],$01);  { var }
              end;
          end;
        { import functions }
        NextImportFunctionIndex:=0;
        for i:=0 to Data.ObjSymbolList.Count-1 do
          begin
            objsym:=TWasmObjSymbol(Data.ObjSymbolList[i]);
            if IsExternalFunction(objsym) then
              begin
                objsym.FuncIndex:=NextImportFunctionIndex;
                Inc(NextImportFunctionIndex);
                objsym.ExtraData:=TWasmObjSymbolExtraData(FData.FObjSymbolsExtraDataList.Find(objsym.Name));
                if objsym.ExtraData.ImportModule<>'' then
                  WriteName(FWasmSections[wsiImport],objsym.ExtraData.ImportModule)
                else
                  WriteName(FWasmSections[wsiImport],'env');
                WriteName(FWasmSections[wsiImport],objsym.Name);
                WriteByte(FWasmSections[wsiImport],$00);  { func }
                WriteUleb(FWasmSections[wsiImport],TWasmObjSymbolExtraData(FData.FObjSymbolsExtraDataList.Find(objsym.Name)).TypeIdx);
              end;
          end;
        { import tables }
        WriteName(FWasmSections[wsiImport],'env');
        WriteName(FWasmSections[wsiImport],'__indirect_function_table');
        WriteByte(FWasmSections[wsiImport],$01);  { table }
        WriteByte(FWasmSections[wsiImport],$70);  { funcref }
        WriteByte(FWasmSections[wsiImport],$00);  { min }
        WriteUleb(FWasmSections[wsiImport],1);    { 1 }
        { import tags }
        NextTagIndex:=0;
        for i:=0 to Data.ObjSymbolList.Count-1 do
          begin
            objsym:=TWasmObjSymbol(Data.ObjSymbolList[i]);
            if (objsym.typ=AT_WASM_EXCEPTION_TAG) and (objsym.bind=AB_EXTERNAL) then
              begin
                objsym.TagIndex:=NextTagIndex;
                Inc(NextTagIndex);
                objsym.ExtraData:=TWasmObjSymbolExtraData(FData.FObjSymbolsExtraDataList.Find(objsym.Name));
                if objsym.ExtraData.ImportModule<>'' then
                  WriteName(FWasmSections[wsiImport],objsym.ExtraData.ImportModule)
                else
                  WriteName(FWasmSections[wsiImport],'env');
                WriteName(FWasmSections[wsiImport],objsym.Name);
                WriteByte(FWasmSections[wsiImport],$04);  { tag }
                WriteByte(FWasmSections[wsiImport],$00);  { exception }
                WriteUleb(FWasmSections[wsiImport],objsym.ExtraData.ExceptionTagTypeIdx);
              end;
          end;

        WriteUleb(FWasmSections[wsiFunction],functions_count);
        NextFunctionIndex:=NextImportFunctionIndex;
        for i:=0 to Data.ObjSymbolList.Count-1 do
          begin
            objsym:=TWasmObjSymbol(Data.ObjSymbolList[i]);
            if (objsym.typ=AT_FUNCTION) and not objsym.IsAlias then
              begin
                objsym.FuncIndex:=NextFunctionIndex;
                Inc(NextFunctionIndex);
                WriteUleb(FWasmSections[wsiFunction],TWasmObjSymbolExtraData(FData.FObjSymbolsExtraDataList.Find(objsym.Name)).TypeIdx);
              end;
          end;

        if exception_tags_count>0 then
          begin
            WriteUleb(FWasmSections[wsiTag],exception_tags_count);
            for i:=0 to Data.ObjSymbolList.Count-1 do
              begin
                objsym:=TWasmObjSymbol(Data.ObjSymbolList[i]);
                if (objsym.typ=AT_WASM_EXCEPTION_TAG) and (objsym.bind<>AB_EXTERNAL) then
                  begin
                    objsym.TagIndex:=NextTagIndex;
                    Inc(NextTagIndex);
                    objsym.ExtraData:=TWasmObjSymbolExtraData(FData.FObjSymbolsExtraDataList.Find(objsym.Name));
                    WriteByte(FWasmSections[wsiTag],$00);  { exception }
                    WriteUleb(FWasmSections[wsiTag],objsym.ExtraData.ExceptionTagTypeIdx);
                  end;
              end;
          end;

        if globals_count>0 then
          begin
            WriteUleb(FWasmSections[wsiGlobal],globals_count);
            for i:=0 to Data.ObjSymbolList.Count-1 do
              begin
                objsym:=TWasmObjSymbol(Data.ObjSymbolList[i]);
                if (objsym.typ=AT_WASM_GLOBAL) and (objsym.bind<>AB_EXTERNAL) then
                  begin
                    objsym.GlobalIndex:=NextGlobalIndex;
                    Inc(NextGlobalIndex);
                    objsym.ExtraData:=TWasmObjSymbolExtraData(FData.FObjSymbolsExtraDataList.Find(objsym.Name));
                    WriteWasmBasicType(FWasmSections[wsiGlobal],objsym.ExtraData.GlobalType);
                    if objsym.ExtraData.GlobalIsImmutable then
                      WriteByte(FWasmSections[wsiGlobal],$00)   { const }
                    else
                      WriteByte(FWasmSections[wsiGlobal],$01);  { var }
                    { init expr }
                    case objsym.ExtraData.GlobalType of
                      wbt_i32:
                        begin
                          WriteByte(FWasmSections[wsiGlobal],$41);  { i32.const }
                          WriteByte(FWasmSections[wsiGlobal],0);    { 0 (in signed LEB128 format) }
                          WriteByte(FWasmSections[wsiGlobal],$0B);  { end }
                        end;
                      wbt_i64:
                        begin
                          WriteByte(FWasmSections[wsiGlobal],$42);  { i64.const }
                          WriteByte(FWasmSections[wsiGlobal],0);    { 0 (in signed LEB128 format) }
                          WriteByte(FWasmSections[wsiGlobal],$0B);  { end }
                        end;
                      wbt_f32:
                        begin
                          WriteByte(FWasmSections[wsiGlobal],$43);  { f32.const }
                          WriteByte(FWasmSections[wsiGlobal],$00);  { 0 (in little endian IEEE single precision floating point format) }
                          WriteByte(FWasmSections[wsiGlobal],$00);
                          WriteByte(FWasmSections[wsiGlobal],$00);
                          WriteByte(FWasmSections[wsiGlobal],$00);
                          WriteByte(FWasmSections[wsiGlobal],$0B);  { end }
                        end;
                      wbt_f64:
                        begin
                          WriteByte(FWasmSections[wsiGlobal],$44);  { f64.const }
                          WriteByte(FWasmSections[wsiGlobal],$00);  { 0 (in little endian IEEE double precision floating point format) }
                          WriteByte(FWasmSections[wsiGlobal],$00);
                          WriteByte(FWasmSections[wsiGlobal],$00);
                          WriteByte(FWasmSections[wsiGlobal],$00);
                          WriteByte(FWasmSections[wsiGlobal],$00);
                          WriteByte(FWasmSections[wsiGlobal],$00);
                          WriteByte(FWasmSections[wsiGlobal],$00);
                          WriteByte(FWasmSections[wsiGlobal],$00);
                          WriteByte(FWasmSections[wsiGlobal],$0B);  { end }
                        end;
                      wbt_externref:
                        begin
                          WriteByte(FWasmSections[wsiGlobal],$D0); { ref.null extern }
                          WriteByte(FWasmSections[wsiGlobal],$6F);
                          WriteByte(FWasmSections[wsiGlobal],$0B);  { end }
                        end;
                      wbt_funcref:
                        begin
                          WriteByte(FWasmSections[wsiGlobal],$D0); { ref.null func }
                          WriteByte(FWasmSections[wsiGlobal],$70);
                          WriteByte(FWasmSections[wsiGlobal],$0B);  { end }
                        end;
                      else
                        internalerror(2022052801);
                    end;
                  end;
              end;
          end;

        if export_functions_count>0 then
          begin
            WriteUleb(FWasmSections[wsiExport],export_functions_count);
            for i:=0 to Data.ObjSymbolList.Count-1 do
              begin
                objsym:=TWasmObjSymbol(Data.ObjSymbolList[i]);
                if IsExportedFunction(objsym) then
                  begin
                    WriteName(FWasmSections[wsiExport],TWasmObjSymbolExtraData(FData.FObjSymbolsExtraDataList.Find(objsym.Name)).ExportName);
                    WriteByte(FWasmSections[wsiExport],0);  { func }
                    if (objsym.FuncIndex<0) then
                      message1(asmw_e_illegal_unset_index,objsym.name)
                    else
                      WriteUleb(FWasmSections[wsiExport],objsym.FuncIndex);
                  end;
              end;
          end;

        Writer.write(WasmModuleMagic,SizeOf(WasmModuleMagic));
        Writer.write(WasmVersion,SizeOf(WasmVersion));

        if ts_wasm_threads in current_settings.targetswitches then
          begin
            WriteUleb(FWasmCustomSections[wcstTargetFeatures],4);
            WriteUleb(FWasmCustomSections[wcstTargetFeatures],$2B);
            WriteName(FWasmCustomSections[wcstTargetFeatures],'atomics');
            WriteUleb(FWasmCustomSections[wcstTargetFeatures],$2B);
            WriteName(FWasmCustomSections[wcstTargetFeatures],'bulk-memory');
            WriteUleb(FWasmCustomSections[wcstTargetFeatures],$2B);
            WriteName(FWasmCustomSections[wcstTargetFeatures],'mutable-globals');
            WriteUleb(FWasmCustomSections[wcstTargetFeatures],$2B);
            WriteName(FWasmCustomSections[wcstTargetFeatures],'sign-ext');
          end
        else
          begin
            WriteUleb(FWasmCustomSections[wcstTargetFeatures],3);
            WriteUleb(FWasmCustomSections[wcstTargetFeatures],$2B);
            WriteName(FWasmCustomSections[wcstTargetFeatures],'bulk-memory');
            WriteUleb(FWasmCustomSections[wcstTargetFeatures],$2B);
            WriteName(FWasmCustomSections[wcstTargetFeatures],'mutable-globals');
            WriteUleb(FWasmCustomSections[wcstTargetFeatures],$2B);
            WriteName(FWasmCustomSections[wcstTargetFeatures],'sign-ext');
          end;

        { Write the producers section:
          https://github.com/WebAssembly/tool-conventions/blob/main/ProducersSection.md }
        WriteUleb(FWasmCustomSections[wcstProducers],2);
        WriteName(FWasmCustomSections[wcstProducers],'language');
        WriteUleb(FWasmCustomSections[wcstProducers],1);
        WriteName(FWasmCustomSections[wcstProducers],'Pascal');
        WriteName(FWasmCustomSections[wcstProducers],'');
        WriteName(FWasmCustomSections[wcstProducers],'processed-by');
        WriteUleb(FWasmCustomSections[wcstProducers],1);
        WriteName(FWasmCustomSections[wcstProducers],'Free Pascal Compiler (FPC)');
        WriteName(FWasmCustomSections[wcstProducers],full_version_string+' ['+date_string+'] for '+target_cpu_string+' - '+target_info.shortname);

        code_section_nr:=-1;
        data_section_nr:=-1;
        debug_abbrev_section_nr:=-1;
        debug_info_section_nr:=-1;
        debug_str_section_nr:=-1;
        debug_line_section_nr:=-1;
        debug_frame_section_nr:=-1;
        debug_aranges_section_nr:=-1;
        debug_ranges_section_nr:=-1;
        section_nr:=0;

        WriteWasmSection(wsiType);
        Inc(section_nr);
        WriteWasmSection(wsiImport);
        Inc(section_nr);
        WriteWasmSection(wsiFunction);
        Inc(section_nr);
        if exception_tags_count>0 then
          begin
            WriteWasmSection(wsiTag);
            Inc(section_nr);
          end;
        if globals_count>0 then
          begin
            WriteWasmSection(wsiGlobal);
            Inc(section_nr);
          end;
        if export_functions_count>0 then
          begin
            WriteWasmSection(wsiExport);
            Inc(section_nr);
          end;

        { determine the section numbers for the datacount, code, data and debug sections ahead of time }
        if segment_count>0 then
          Inc(section_nr);  { the DataCount section }
        code_section_nr:=section_nr;  { the Code section }
        Inc(section_nr);
        if segment_count>0 then
          begin
            data_section_nr:=section_nr; { the Data section }
            Inc(section_nr);
          end;
        { the debug sections }
        MaybeAddDebugSectionToSymbolTable(wcstDebugAbbrev,debug_abbrev_section_nr);
        MaybeAddDebugSectionToSymbolTable(wcstDebugInfo,debug_info_section_nr);
        MaybeAddDebugSectionToSymbolTable(wcstDebugStr,debug_str_section_nr);
        MaybeAddDebugSectionToSymbolTable(wcstDebugLine,debug_line_section_nr);
        MaybeAddDebugSectionToSymbolTable(wcstDebugFrame,debug_frame_section_nr);
        MaybeAddDebugSectionToSymbolTable(wcstDebugAranges,debug_aranges_section_nr);
        MaybeAddDebugSectionToSymbolTable(wcstDebugRanges,debug_ranges_section_nr);

        for i:=0 to Data.ObjSymbolList.Count-1 do
          begin
            objsym:=TWasmObjSymbol(Data.ObjSymbolList[i]);
            if objsym.typ=AT_WASM_EXCEPTION_TAG then
              begin
                objsym.SymbolIndex:=FWasmSymbolTableEntriesCount;
                Inc(FWasmSymbolTableEntriesCount);
                WriteByte(FWasmSymbolTable,Ord(SYMTAB_EVENT));
                if objsym.bind=AB_GLOBAL then
                  WriteUleb(FWasmSymbolTable,0)
                else if objsym.bind=AB_LOCAL then
                  WriteUleb(FWasmSymbolTable,WASM_SYM_BINDING_LOCAL)
                else if objsym.bind=AB_EXTERNAL then
                  WriteUleb(FWasmSymbolTable,WASM_SYM_UNDEFINED)
                else if objsym.bind=AB_WEAK then
                  WriteUleb(FWasmSymbolTable,WASM_SYM_BINDING_WEAK)
                else
                  internalerror(2021092715);
                if (objsym.TagIndex<0) then
                  message1(asmw_e_illegal_unset_index,objsym.name)
                else
                  WriteUleb(FWasmSymbolTable,objsym.TagIndex);
                if objsym.bind<>AB_EXTERNAL then
                  WriteName(FWasmSymbolTable,objsym.Name);
              end
            else if objsym.typ=AT_WASM_GLOBAL then
              begin
                objsym.SymbolIndex:=FWasmSymbolTableEntriesCount;
                Inc(FWasmSymbolTableEntriesCount);
                WriteByte(FWasmSymbolTable,Ord(SYMTAB_GLOBAL));
                if objsym.bind=AB_EXTERNAL then
                  begin
                    WriteUleb(FWasmSymbolTable,WASM_SYM_UNDEFINED);
                    if (objsym.GlobalIndex<0) then
                      message1(asmw_e_illegal_unset_index,objsym.name)
                    else
                      WriteUleb(FWasmSymbolTable,objsym.GlobalIndex);
                  end
                else
                  begin
                    WriteUleb(FWasmSymbolTable,0);
                    if (objsym.GlobalIndex<0) then
                      message1(asmw_e_illegal_unset_index,objsym.name)
                    else
                      WriteUleb(FWasmSymbolTable,objsym.GlobalIndex);
                    WriteName(FWasmSymbolTable,objsym.Name);
                  end;
              end
            else if IsExternalFunction(objsym) then
              begin
                objsym.SymbolIndex:=FWasmSymbolTableEntriesCount;
                Inc(FWasmSymbolTableEntriesCount);
                WriteByte(FWasmSymbolTable,Ord(SYMTAB_FUNCTION));
                if objsym.ExtraData.ImportModule<>'' then
                  begin
                    WriteUleb(FWasmSymbolTable,WASM_SYM_UNDEFINED or WASM_SYM_EXPLICIT_NAME);
                    if (objsym.FuncIndex<0) then
                      message1(asmw_e_illegal_unset_index,objsym.name)
                    else
                      WriteUleb(FWasmSymbolTable,objsym.FuncIndex);
                    WriteName(FWasmSymbolTable,objsym.Name);
                  end
                else
                  begin
                    WriteUleb(FWasmSymbolTable,WASM_SYM_UNDEFINED);
                    if (objsym.FuncIndex<0) then
                      message1(asmw_e_illegal_unset_index,objsym.name)
                    else
                      WriteUleb(FWasmSymbolTable,objsym.FuncIndex);
                  end;
              end
            else if objsym.typ=AT_FUNCTION then
              begin
                objsym.SymbolIndex:=FWasmSymbolTableEntriesCount;
                Inc(FWasmSymbolTableEntriesCount);
                WriteByte(FWasmSymbolTable,Ord(SYMTAB_FUNCTION));
                if objsym.IsAlias then
                  begin
                    ObjSymAlias:=TWasmObjSymbol(Data.ObjSymbolList.Find(objsym.AliasOf));
                    ObjSym.FuncIndex:=ObjSymAlias.FuncIndex;
                    WriteUleb(FWasmSymbolTable,WASM_SYM_EXPLICIT_NAME or WASM_SYM_NO_STRIP);
                    WriteUleb(FWasmSymbolTable,ObjSymAlias.FuncIndex);
                  end
                else
                  begin
                    if IsExportedFunction(objsym) then
                      WriteUleb(FWasmSymbolTable,WASM_SYM_EXPORTED)
                    else
                      WriteUleb(FWasmSymbolTable,0);
                    if (objsym.FuncIndex<0) then
                      message1(asmw_e_illegal_unset_index,objsym.name)
                    else
                      WriteUleb(FWasmSymbolTable,objsym.FuncIndex);
                  end;
                WriteName(FWasmSymbolTable,objsym.Name);
              end
            else if (objsym.typ in [AT_DATA,AT_TLS,AT_METADATA]) or ((objsym.typ=AT_NONE) and (objsym.bind=AB_EXTERNAL)) then
              begin
                if (objsym.bind<>AB_EXTERNAL) and TWasmObjSection(objsym.objsection).IsDebug then
                  begin
                    objsym.SymbolIndex:=FWasmSymbolTableEntriesCount;
                    Inc(FWasmSymbolTableEntriesCount);
                    WriteByte(FWasmSymbolTable,Ord(SYMTAB_FPC_CUSTOM));
                    if objsym.bind=AB_GLOBAL then
                      SymbolFlags:=0
                    else if objsym.bind=AB_LOCAL then
                      SymbolFlags:=WASM_SYM_BINDING_LOCAL
                    else if objsym.bind=AB_EXTERNAL then
                      SymbolFlags:=WASM_SYM_UNDEFINED
                    else
                      internalerror(2024090701);
                    WriteUleb(FWasmSymbolTable,SymbolFlags);
                    WriteName(FWasmSymbolTable,objsym.Name);
                    WriteUleb(FWasmSymbolTable,TWasmObjSection(objsym.objsection).CustomSectionIdx);
                    WriteUleb(FWasmSymbolTable,objsym.offset);
                    WriteUleb(FWasmSymbolTable,objsym.size);
                  end
                else
                  begin
                    objsym.SymbolIndex:=FWasmSymbolTableEntriesCount;
                    Inc(FWasmSymbolTableEntriesCount);
                    WriteByte(FWasmSymbolTable,Ord(SYMTAB_DATA));
                    if objsym.bind=AB_GLOBAL then
                      SymbolFlags:=0
                    else if objsym.bind=AB_LOCAL then
                      SymbolFlags:=WASM_SYM_BINDING_LOCAL
                    else if objsym.bind=AB_EXTERNAL then
                      SymbolFlags:=WASM_SYM_UNDEFINED
                    else
                      internalerror(2021092506);
                    if (objsym.typ=AT_TLS) and (ts_wasm_threads in current_settings.targetswitches) then
                      SymbolFlags:=(SymbolFlags and not WASM_SYM_BINDING_LOCAL) or WASM_SYM_TLS;
                    WriteUleb(FWasmSymbolTable,SymbolFlags);
                    WriteName(FWasmSymbolTable,objsym.Name);
                    if objsym.bind<>AB_EXTERNAL then
                      begin
                        WriteUleb(FWasmSymbolTable,TWasmObjSection(objsym.objsection).SegIdx);
                        WriteUleb(FWasmSymbolTable,objsym.offset);
                        WriteUleb(FWasmSymbolTable,objsym.size);
                      end;
                  end;
              end;
          end;

        DoRelocations;

        if segment_count>0 then
          begin
            WriteUleb(FWasmSections[wsiData],segment_count);
            WriteUleb(FWasmSections[wsiDataCount],segment_count);
            WriteUleb(FWasmLinkingSubsections[WASM_SEGMENT_INFO],segment_count);
            for i:=0 to Data.ObjSectionList.Count-1 do
              begin
                objsec:=TWasmObjSection(Data.ObjSectionList[i]);
                if objsec.IsData then
                  begin
                    WriteName(FWasmLinkingSubsections[WASM_SEGMENT_INFO],objsec.Name);
                    WriteUleb(FWasmLinkingSubsections[WASM_SEGMENT_INFO],BsrQWord(objsec.SecAlign));
                    SegmentFlags:=0;
                    if (ts_wasm_threads in current_settings.targetswitches) and
                       (oso_threadvar in objsec.SecOptions) then
                      SegmentFlags:=SegmentFlags or WASM_SEG_FLAG_TLS;
                    WriteUleb(FWasmLinkingSubsections[WASM_SEGMENT_INFO],SegmentFlags);  { flags }

                    WriteByte(FWasmSections[wsiData],0);
                    WriteByte(FWasmSections[wsiData],$41);
                    WriteSleb(FWasmSections[wsiData],objsec.SegOfs);
                    WriteByte(FWasmSections[wsiData],$0b);
                    WriteUleb(FWasmSections[wsiData],objsec.Size);
                    objsec.FileSectionOfs:=FWasmSections[wsiData].size;
                    if oso_Data in objsec.SecOptions then
                      begin
                        objsec.Data.seek(0);
                        CopyDynamicArray(objsec.Data,FWasmSections[wsiData],objsec.Size);
                      end
                    else
                      begin
                        WriteZeros(FWasmSections[wsiData],objsec.Size);
                      end;
                  end;
              end;
          end;

        WriteUleb(FWasmSections[wsiCode],functions_count);
        for i:=0 to Data.ObjSymbolList.Count-1 do
          begin
            objsym:=TWasmObjSymbol(Data.ObjSymbolList[i]);
            if (objsym.typ=AT_FUNCTION) and not objsym.IsAlias then
              WriteFunctionCode(FWasmSections[wsiCode],objsym);
          end;

        if segment_count>0 then
          WriteWasmSection(wsiDataCount);
        WriteWasmSection(wsiCode);
        if segment_count>0 then
          WriteWasmSection(wsiData);

        MaybeWriteDebugSection(wcstDebugAbbrev);
        MaybeWriteDebugSection(wcstDebugInfo);
        MaybeWriteDebugSection(wcstDebugStr);
        MaybeWriteDebugSection(wcstDebugLine);
        MaybeWriteDebugSection(wcstDebugFrame);
        MaybeWriteDebugSection(wcstDebugAranges);
        MaybeWriteDebugSection(wcstDebugRanges);

        WriteRelocations;

        WriteSymbolTable;
        WriteLinkingSubsection(WASM_SYMBOL_TABLE);
        if segment_count>0 then
          WriteLinkingSubsection(WASM_SEGMENT_INFO);

        WriteRelocationCodeTable(code_section_nr);
        if segment_count>0 then
          WriteRelocationDataTable(data_section_nr);

        WriteWasmCustomSection(wcstLinking);
        Inc(section_nr);
        WriteWasmCustomSection(wcstRelocCode);
        Inc(section_nr);
        if segment_count>0 then
          begin
            WriteWasmCustomSection(wcstRelocData);
            Inc(section_nr);
          end;
        MaybeWriteRelocationDebugTable(wcstRelocDebugAbbrev,debug_abbrev_section_nr,FWasmRelocationDebugAbbrevTableEntriesCount,FWasmRelocationDebugAbbrevTable);
        MaybeWriteRelocationDebugTable(wcstRelocDebugInfo,debug_info_section_nr,FWasmRelocationDebugInfoTableEntriesCount,FWasmRelocationDebugInfoTable);
        MaybeWriteRelocationDebugTable(wcstRelocDebugStr,debug_str_section_nr,FWasmRelocationDebugStrTableEntriesCount,FWasmRelocationDebugStrTable);
        MaybeWriteRelocationDebugTable(wcstRelocDebugLine,debug_line_section_nr,FWasmRelocationDebugLineTableEntriesCount,FWasmRelocationDebugLineTable);
        MaybeWriteRelocationDebugTable(wcstRelocDebugFrame,debug_frame_section_nr,FWasmRelocationDebugFrameTableEntriesCount,FWasmRelocationDebugFrameTable);
        MaybeWriteRelocationDebugTable(wcstRelocDebugAranges,debug_aranges_section_nr,FWasmRelocationDebugArangesTableEntriesCount,FWasmRelocationDebugArangesTable);
        MaybeWriteRelocationDebugTable(wcstRelocDebugRanges,debug_ranges_section_nr,FWasmRelocationDebugRangesTableEntriesCount,FWasmRelocationDebugRangesTable);
        WriteWasmCustomSection(wcstProducers);
        Inc(section_nr);
        WriteWasmCustomSection(wcstTargetFeatures);
        Inc(section_nr);

        result:=true;
      end;

    constructor TWasmObjOutput.create(AWriter: TObjectWriter);
      var
        i: TWasmSectionID;
        j: TWasmCustomSectionType;
        k: TWasmLinkingSubsectionType;
      begin
        inherited;
        cobjdata:=TWasmObjData;
        for i in TWasmSectionID do
          FWasmSections[i] := tdynamicarray.create(SectionDataMaxGrow);
        for j in TWasmCustomSectionType do
          FWasmCustomSections[j] := tdynamicarray.create(SectionDataMaxGrow);
        for k:=low(TWasmLinkingSubsectionType) to high(TWasmLinkingSubsectionType) do
          FWasmLinkingSubsections[k] := tdynamicarray.create(SectionDataMaxGrow);
        FWasmSymbolTable:=tdynamicarray.create(SectionDataMaxGrow);
        FWasmSymbolTableEntriesCount:=0;
        FWasmRelocationCodeTable:=tdynamicarray.create(SectionDataMaxGrow);
        FWasmRelocationCodeTableEntriesCount:=0;
        FWasmRelocationDataTable:=tdynamicarray.create(SectionDataMaxGrow);
        FWasmRelocationDataTableEntriesCount:=0;
        FWasmRelocationDebugFrameTable:=tdynamicarray.create(SectionDataMaxGrow);
        FWasmRelocationDebugFrameTableEntriesCount:=0;
        FWasmRelocationDebugInfoTable:=tdynamicarray.create(SectionDataMaxGrow);
        FWasmRelocationDebugInfoTableEntriesCount:=0;
        FWasmRelocationDebugLineTable:=tdynamicarray.create(SectionDataMaxGrow);
        FWasmRelocationDebugLineTableEntriesCount:=0;
        FWasmRelocationDebugAbbrevTable:=tdynamicarray.create(SectionDataMaxGrow);
        FWasmRelocationDebugAbbrevTableEntriesCount:=0;
        FWasmRelocationDebugArangesTable:=tdynamicarray.create(SectionDataMaxGrow);
        FWasmRelocationDebugArangesTableEntriesCount:=0;
        FWasmRelocationDebugRangesTable:=tdynamicarray.create(SectionDataMaxGrow);
        FWasmRelocationDebugRangesTableEntriesCount:=0;
        FWasmRelocationDebugStrTable:=tdynamicarray.create(SectionDataMaxGrow);
        FWasmRelocationDebugStrTableEntriesCount:=0;
      end;

    destructor TWasmObjOutput.destroy;
      var
        i: TWasmSectionID;
        j: TWasmCustomSectionType;
        k: TWasmLinkingSubsectionType;
      begin
        for i in TWasmSectionID do
          FWasmSections[i].Free;
        for j in TWasmCustomSectionType do
          FWasmCustomSections[j].Free;
        for k:=low(TWasmLinkingSubsectionType) to high(TWasmLinkingSubsectionType) do
          FWasmLinkingSubsections[k].Free;
        FWasmSymbolTable.Free;
        FWasmRelocationCodeTable.Free;
        FWasmRelocationDataTable.Free;
        FWasmRelocationDebugFrameTable.Free;
        FWasmRelocationDebugInfoTable.Free;
        FWasmRelocationDebugLineTable.Free;
        FWasmRelocationDebugAbbrevTable.Free;
        FWasmRelocationDebugArangesTable.Free;
        FWasmRelocationDebugRangesTable.Free;
        FWasmRelocationDebugStrTable.Free;
        inherited destroy;
      end;

{****************************************************************************
                               TWasmObjInput
****************************************************************************}

    constructor TWasmObjInput.create;
      begin
        inherited create;
        cobjdata:=TWasmObjData;
      end;

    destructor TWasmObjInput.Destroy;
      var
        i: Integer;
      begin
        for i:=low(FFuncTypes) to high(FFuncTypes) do
          begin
            FFuncTypes[i].free;
            FFuncTypes[i]:=nil;
          end;
        inherited Destroy;
      end;

    class function TWasmObjInput.CanReadObjData(AReader: TObjectreader): boolean;
      var
        ModuleMagic: array [0..3] of Byte;
        ModuleVersion: array [0..3] of Byte;
        i: Integer;
      begin
        result:=false;
        if not AReader.read(ModuleMagic,4) then
          exit;
        for i:=0 to 3 do
          if ModuleMagic[i]<>WasmModuleMagic[i] then
            exit;
        if not AReader.read(ModuleVersion,4) then
          exit;
        for i:=0 to 3 do
          if ModuleVersion[i]<>WasmVersion[i] then
            exit;
        result:=true;
      end;

    function TWasmObjInput.ReadObjData(AReader: TObjectreader; out ObjData: TObjData): boolean;

      type
        TLimits = record
          Min, Max: uint32;
          HasMax: Boolean;
        end;

      var
        SectionIndex: Integer = -1;
        SectionId: Byte;
        SectionSize: uint32;
        SectionStart: LongInt;
        CheckSectionBounds: Boolean;

        TypeSectionRead: Boolean = false;
        ImportSectionRead: Boolean = false;
        FunctionSectionRead: Boolean = false;
        GlobalSectionRead: Boolean = false;
        ExportSectionRead: Boolean = false;
        ElementSectionRead: Boolean = false;
        TagSectionRead: Boolean = false;
        CodeSectionRead: Boolean = false;
        DataSectionRead: Boolean = false;
        DataCountSectionRead: Boolean = false;

        SegmentInfoSectionRead: Boolean = false;
        SymbolTableSectionRead: Boolean = false;

        CodeSectionIndex: Integer = -1;
        DataSectionIndex: Integer = -1;
        DebugSectionIndex: array [TWasmCustomDebugSectionType] of Integer = (-1,-1,-1,-1,-1,-1,-1);

        FuncTypes: array of record
          IsImport: Boolean;
          ImportName: ansistring;
          ImportModName: ansistring;
          typidx: uint32;
          IsExported: Boolean;
          ExportName: ansistring;
        end;
        FuncTypeImportsCount: uint32;

        TableTypes: array of record
          IsImport: Boolean;
          ImportName: ansistring;
          ImportModName: ansistring;
          reftype: TWasmBAsicType;
          limits: TLimits;
          IsExported: Boolean;
          ExportName: ansistring;
        end;
        TableTypeImportsCount: uint32;

        MemTypes: array of record
          IsImport: Boolean;
          ImportName: ansistring;
          ImportModName: ansistring;
          limits: TLimits;
          IsExported: Boolean;
          ExportName: ansistring;
        end;
        MemTypeImportsCount: uint32;

        GlobalTypes: array of record
          IsImport: Boolean;
          ImportName: ansistring;
          ImportModName: ansistring;
          valtype: TWasmBasicType;
          IsMutable: Boolean;
          IsExported: Boolean;
          ExportName: ansistring;
          GlobalInit: TGlobalInitializer;
        end;
        GlobalTypeImportsCount: uint32;

        TagTypes: array of record
          IsImport: Boolean;
          ImportName: ansistring;
          ImportModName: ansistring;
          TagAttr: Byte;
          TagTypeIdx: uint32;
          IsExported: Boolean;
          ExportName: ansistring;
        end;
        TagTypeImportsCount: uint32;

        CodeSegments: array of record
          CodeSectionOffset: uint32;
          CodeSize: uint32;
          DataPos: LongInt;
          SegName: ansistring;
          SegIsExported: Boolean;
        end;

        DataSegments: array of record
          DataSectionOffset: uint32;
          Active: Boolean;
          MemIdx: uint32;
          Len: uint32;
          Offset: int32;
          DataPos: LongInt;
          SegName: ansistring;
          SegAlignment: uint32;
          SegFlags: uint32;
        end;

        SymbolTable: array of record
          SymFlags: uint32;
          TargetSection: uint32;
          SymIndex: uint32;
          SymOffset: uint32;
          SymSize: uint32;
          SymCustomSectionIndex: uint32;
          SymCustomSectionType: TWasmCustomDebugSectionType;
          SymKind: TWasmSymbolType;
          SymName: ansistring;
          ObjSym: TWasmObjSymbol;
          ObjSec: TWasmObjSection;
        end;

        { meaning of first index: }
        {   table 0 is code relocs }
        {   table 1 is data relocs }
        {   tables 2.. are custom section relocs for debug sections }
        RelocationTable: array of array of record
          RelocType: TWasmRelocationType;
          RelocOffset: uint32;
          RelocIndex: uint32;
          RelocAddend: int32;
        end;

      function FindDebugSectionByIndex(SectionIndex: Integer; out res: TWasmCustomDebugSectionType): Boolean;
        var
          ds: TWasmCustomDebugSectionType;
        begin
          for ds in TWasmCustomDebugSectionType do
            if DebugSectionIndex[ds]=SectionIndex then
              begin
                Res:=ds;
                Result:=True;
                exit;
              end;
          Res:=low(TWasmCustomDebugSectionType);
          Result:=False;
        end;

      function ReadSection: Boolean;

        function read(out b;len:longint):boolean;
          begin
            result:=false;
            if not CheckSectionBounds or ((AReader.Pos+len)<=(SectionStart+SectionSize)) then
              result:=AReader.read(b,len)
            else
              begin
                { trying to read beyond the end of the section }
                AReader.read(b,SectionStart+SectionSize-AReader.Pos);
                result:=false;
              end;
          end;

        function ReadUleb(out v: uint64): boolean;
          var
            b: byte;
            shift:integer;
          begin
            result:=false;
            b:=0;
            v:=0;
            shift:=0;
            repeat
              if not read(b,1) then
                exit;
              v:=v or (uint64(b and 127) shl shift);
              inc(shift,7);
            until (b and 128)=0;
            result:=true;
          end;

        function ReadUleb32(out v: uint32): boolean;
          var
            vv: uint64;
          begin
            result:=false;
            v:=default(uint32);
            if not ReadUleb(vv) then
              exit;
            if vv>high(uint32) then
              exit;
            v:=vv;
            result:=true;
          end;

        function ReadSleb(out v: int64): boolean;
          var
            b: byte;
            shift:integer;
          begin
            result:=false;
            b:=0;
            v:=0;
            shift:=0;
            repeat
              if not read(b,1) then
                exit;
              v:=v or (uint64(b and 127) shl shift);
              inc(shift,7);
            until (b and 128)=0;
{$ifopt Q+}
{$define overflowon}
{$Q-}
{$endif}
{$ifopt R+}
{$define rangeon}
{$R-}
{$endif}
            if (b and 64)<>0 then
              v:=v or (high(uint64) shl shift);
            result:=true;
          end;
{$ifdef overflowon}
{$Q+}
{$undef overflowon}
{$endif}
{$ifdef rangeon}
{$R+}
{$undef rangeon}
{$endif}

        function ReadSleb32(out v: int32): boolean;
          var
            vv: int64;
          begin
            result:=false;
            v:=default(int32);
            if not ReadSleb(vv) then
              exit;
            if (vv>high(int32)) or (vv<low(int32)) then
              exit;
            v:=vv;
            result:=true;
          end;

        function ReadName(out v: ansistring): boolean;
          var
            len: uint32;
          begin
            result:=false;
            if not ReadUleb32(len) then
              exit;
            SetLength(v,len);
            if len>0 then
              result:=read(v[1],len)
            else
              result:=true;
          end;

        function ReadCustomSection: Boolean;

          function ReadRelocationSection: Boolean;
            var
              TargetSection, RelocCount: uint32;
              i: Integer;
              RelocTableIndex: Integer;
              ds: TWasmCustomDebugSectionType;
            begin
              Result:=False;
              if not ReadUleb32(TargetSection) then
                begin
                  InputError('Error reading the index of the target section of a relocation section');
                  exit;
                end;
              if TargetSection=CodeSectionIndex then
                RelocTableIndex:=0
              else if TargetSection=DataSectionIndex then
                RelocTableIndex:=1
              else
                begin
                  RelocTableIndex:=-1;
                  for ds:=Low(DebugSectionIndex) to High(DebugSectionIndex) do
                    if DebugSectionIndex[ds]=TargetSection then
                      begin
                        RelocTableIndex:=2+(Ord(ds)-Ord(Low(TWasmCustomDebugSectionType)));
                        break;
                      end;
                  if RelocTableIndex=-1 then
                    begin
                      InputError('Relocation found for a custom section, that is not supported');
                      exit;
                    end;
                end;
              if not ReadUleb32(RelocCount) then
                begin
                  InputError('Error reading the relocation entries count from a relocation section');
                  exit;
                end;
              SetLength(RelocationTable[RelocTableIndex],RelocCount);
              for i:=0 to RelocCount-1 do
                with RelocationTable[RelocTableIndex,i] do
                  begin
                    if not Read(RelocType,1) then
                      begin
                        InputError('Error reading the relocation type of a relocation entry');
                        exit;
                      end;
                    if not (RelocType in [R_WASM_FUNCTION_INDEX_LEB,
                                          R_WASM_MEMORY_ADDR_LEB,
                                          R_WASM_TABLE_INDEX_SLEB,
                                          R_WASM_MEMORY_ADDR_SLEB,
                                          R_WASM_SECTION_OFFSET_I32,
                                          R_WASM_TABLE_INDEX_I32,
                                          R_WASM_FUNCTION_OFFSET_I32,
                                          R_WASM_MEMORY_ADDR_I32,
                                          R_WASM_TYPE_INDEX_LEB,
                                          R_WASM_GLOBAL_INDEX_LEB,
                                          R_WASM_TAG_INDEX_LEB,
                                          R_WASM_GLOBAL_INDEX_I32]) then
                      begin
                        InputError('Unsupported relocation type: ' + tostr(Ord(RelocType)));
                        exit;
                      end;
                    if not ReadUleb32(RelocOffset) then
                      begin
                        InputError('Error reading the relocation offset of a relocation entry');
                        exit;
                      end;
                    if not ReadUleb32(RelocIndex) then
                      begin
                        InputError('Error reading the relocation index of a relocation entry');
                        exit;
                      end;
                    if RelocType in [R_WASM_FUNCTION_OFFSET_I32,R_WASM_SECTION_OFFSET_I32,R_WASM_MEMORY_ADDR_LEB,R_WASM_MEMORY_ADDR_SLEB,R_WASM_MEMORY_ADDR_I32] then
                      begin
                        if not ReadSleb32(RelocAddend) then
                          begin
                            InputError('Error reading the relocation addend of a relocation entry');
                            exit;
                          end;
                      end;
                    if (RelocType in [
                          R_WASM_SECTION_OFFSET_I32,
                          R_WASM_FUNCTION_INDEX_LEB,
                          R_WASM_TABLE_INDEX_SLEB,
                          R_WASM_TABLE_INDEX_I32,
                          R_WASM_MEMORY_ADDR_LEB,
                          R_WASM_MEMORY_ADDR_SLEB,
                          R_WASM_MEMORY_ADDR_I32,
                          R_WASM_FUNCTION_OFFSET_I32,
                          R_WASM_GLOBAL_INDEX_LEB,
                          R_WASM_GLOBAL_INDEX_I32]) and (RelocIndex>High(SymbolTable)) then
                      begin
                        InputError('Relocation index outside the bounds of the symbol table');
                        exit;
                      end;
                    if (RelocType=R_WASM_TYPE_INDEX_LEB) and (RelocIndex>High(FFuncTypes)) then
                      begin
                        InputError('Relocation index of R_WASM_TYPE_INDEX_LEB outside the bounds of the func types, defined in the func section of the module');
                        exit;
                      end;
                    if (RelocType=R_WASM_SECTION_OFFSET_I32) and (SymbolTable[RelocIndex].SymKind<>SYMTAB_SECTION) then
                      begin
                        InputError('R_WASM_SECTION_OFFSET_I32 must point to a SYMTAB_SECTION symbol');
                        exit;
                      end;
                    if (RelocType in [R_WASM_GLOBAL_INDEX_LEB,R_WASM_GLOBAL_INDEX_I32]) and
                       not ((SymbolTable[RelocIndex].SymKind=SYMTAB_GLOBAL) or
                            ((ts_wasm_threads in current_settings.targetswitches) and
                             (SymbolTable[RelocIndex].SymKind=SYMTAB_DATA) and
                             ((SymbolTable[RelocIndex].SymFlags and WASM_SYM_TLS)<>0))) then
                      begin
                        if ts_wasm_threads in current_settings.targetswitches then
                          InputError('Relocation must point to a SYMTAB_GLOBAL symbol or a SYMTAB_DATA symbol with the WASM_SYM_TLS flag set')
                        else
                          InputError('Relocation must point to a SYMTAB_GLOBAL symbol');
                        exit;
                      end;
                    if (RelocType=R_WASM_TAG_INDEX_LEB) and (SymbolTable[RelocIndex].SymKind<>SYMTAB_EVENT) then
                      begin
                        InputError('Relocation must point to a SYMTAB_EVENT symbol');
                        exit;
                      end;
                    if (RelocType in [
                          R_WASM_FUNCTION_INDEX_LEB,
                          R_WASM_TABLE_INDEX_SLEB,
                          R_WASM_TABLE_INDEX_I32,
                          R_WASM_FUNCTION_OFFSET_I32]) and (SymbolTable[RelocIndex].SymKind<>SYMTAB_FUNCTION) then
                      begin
                        InputError('Relocation must point to a SYMTAB_FUNCTION symbol');
                        exit;
                      end;
                    if (RelocType in [
                          R_WASM_MEMORY_ADDR_LEB,
                          R_WASM_MEMORY_ADDR_SLEB,
                          R_WASM_MEMORY_ADDR_I32]) and (SymbolTable[RelocIndex].SymKind<>SYMTAB_DATA) then
                      begin
                        InputError('Relocation must point to a SYMTAB_DATA symbol');
                        exit;
                      end;
                  end;
              if AReader.Pos<>(SectionStart+SectionSize) then
                begin
                  InputError('Unexpected relocation section size');
                  exit;
                end;
              Result:=True;
            end;

          function ReadLinkingSection: Boolean;

            function ReadSegmentInfo: Boolean;
              var
                SegmentCount: uint32;
                i: Integer;
              begin
                Result:=False;
                if SegmentInfoSectionRead then
                  begin
                    InputError('The WASM_SEGMENT_INFO subsection is duplicated');
                    exit;
                  end;
                SegmentInfoSectionRead:=True;
                if not ReadUleb32(SegmentCount) then
                  begin
                    InputError('Error reading the segment count from the WASM_SEGMENT_INFO subsection of the ''linking'' section');
                    exit;
                  end;
                if SegmentCount<>Length(DataSegments) then
                  begin
                    InputError('Segment count in the WASM_SEGMENT_INFO subsection does not match the data count in the data section');
                    exit;
                  end;
                for i:=0 to SegmentCount-1 do
                  with DataSegments[i] do
                    begin
                      if not ReadName(SegName) then
                        begin
                          InputError('Error reading segment name from the WASM_SEGMENT_INFO subsection of the ''linking'' section');
                          exit;
                        end;
                      if not ReadUleb32(SegAlignment) then
                        begin
                          InputError('Error reading segment alignment from the WASM_SEGMENT_INFO subsection of the ''linking'' section');
                          exit;
                        end;
                      if not ReadUleb32(SegFlags) then
                        begin
                          InputError('Error reading segment flags from the WASM_SEGMENT_INFO subsection of the ''linking'' section');
                          exit;
                        end;
                    end;
                if AReader.Pos<>(SectionStart+SectionSize) then
                  begin
                    InputError('Unexpected WASM_SEGMENT_INFO section size');
                    exit;
                  end;
                Result:=True;
              end;

            function ReadSymbolTable: Boolean;
              var
                SymCount: uint32;
                i: Integer;
                SymKindName: string;
                SymKindB: Byte;
              begin
                Result:=False;
                if SymbolTableSectionRead then
                  begin
                    InputError('The WASM_SYMBOL_TABLE subsection is duplicated');
                    exit;
                  end;
                SymbolTableSectionRead:=True;
                if not ReadUleb32(SymCount) then
                  begin
                    InputError('Error reading the symbol count from the WASM_SYMBOL_TABLE subsection of the ''linking'' section');
                    exit;
                  end;
                SetLength(SymbolTable,SymCount);
                for i:=0 to SymCount-1 do
                  with SymbolTable[i] do
                    begin
                      if not Read(SymKindB,1) then
                        begin
                          InputError('Error reading symbol type from the WASM_SYMBOL_TABLE subsection of the ''linking'' section');
                          exit;
                        end;
                      if SymKindB>Ord(High(TWasmSymbolType)) then
                        begin
                          InputError('Unsupported symbol type from the WASM_SYMBOL_TABLE subsection of the ''linking'' section');
                          exit;
                        end;
                      SymKind:=TWasmSymbolType(SymKindB);
                      if not ReadUleb32(SymFlags) then
                        begin
                          InputError('Error reading symbol flags from the WASM_SYMBOL_TABLE subsection of the ''linking'' section');
                          exit;
                        end;
                      case SymKind of
                        SYMTAB_FUNCTION,
                        SYMTAB_GLOBAL,
                        SYMTAB_EVENT,
                        SYMTAB_TABLE:
                          begin
                            WriteStr(SymKindName, SymKind);
                            if not ReadUleb32(SymIndex) then
                              begin
                                InputError('Error reading the index of a ' + SymKindName + ' symbol');
                                exit;
                              end;
                            if ((SymKind=SYMTAB_FUNCTION) and (SymIndex>high(FuncTypes))) or
                               ((SymKind=SYMTAB_EVENT) and (SymIndex>high(TagTypes))) then
                              begin
                                InputError('Symbol index too high');
                                exit;
                              end;
                            if ((SymFlags and WASM_SYM_EXPLICIT_NAME)<>0) or
                               ((SymFlags and WASM_SYM_UNDEFINED)=0) then
                              begin
                                if not ReadName(SymName) then
                                  begin
                                    InputError('Error reading symbol name of a ' + SymKindName + ' symbol');
                                    exit;
                                  end;
                              end;
                          end;
                        SYMTAB_DATA:
                          begin
                            if not ReadName(SymName) then
                              begin
                                InputError('Error reading symbol name of a SYMTAB_DATA symbol');
                                exit;
                              end;
                            if (SymFlags and WASM_SYM_UNDEFINED)=0 then
                              begin
                                if not ReadUleb32(SymIndex) then
                                  begin
                                    InputError('Error reading the data segment index of a SYMTAB_DATA symbol');
                                    exit;
                                  end;
                                if SymIndex>high(DataSegments) then
                                  begin
                                    InputError('Data segment index of SYMTAB_DATA symbol out of bounds');
                                    exit;
                                  end;
                                if not ReadUleb32(SymOffset) then
                                  begin
                                    InputError('Error reading the offset of a SYMTAB_DATA symbol');
                                    exit;
                                  end;
                                if not ReadUleb32(SymSize) then
                                  begin
                                    InputError('Error reading the size of a SYMTAB_DATA symbol');
                                    exit;
                                  end;
                              end;
                          end;
                        SYMTAB_FPC_CUSTOM:
                          begin
                            if not ReadName(SymName) then
                              begin
                                InputError('Error reading symbol name of a SYMTAB_FPC_CUSTOM symbol');
                                exit;
                              end;
                            if (SymFlags and WASM_SYM_UNDEFINED)=0 then
                              begin
                                if not ReadUleb32(SymCustomSectionIndex) then
                                  begin
                                    InputError('Error reading the custom section index of a SYMTAB_FPC_CUSTOM symbol');
                                    exit;
                                  end;
                                if not FindDebugSectionByIndex(SymCustomSectionIndex,SymCustomSectionType) then
                                  begin
                                    InputError('Custom section index of SYMTAB_FPC_CUSTOM symbol not pointing to a debug section');
                                    exit;
                                  end;
                                if not ReadUleb32(SymOffset) then
                                  begin
                                    InputError('Error reading the offset of a SYMTAB_FPC_CUSTOM symbol');
                                    exit;
                                  end;
                                if not ReadUleb32(SymSize) then
                                  begin
                                    InputError('Error reading the size of a SYMTAB_FPC_CUSTOM symbol');
                                    exit;
                                  end;
                              end;
                          end;
                        SYMTAB_SECTION:
                          begin
                            if not ReadUleb32(TargetSection) then
                              begin
                                InputError('Error reading the target section of a SYMTAB_SECTION symbol');
                                exit;
                              end;
                          end;
                      end;
                    end;
                if AReader.Pos<>(SectionStart+SectionSize) then
                  begin
                    InputError('Unexpected WASM_SYMBOL_TABLE section size');
                    exit;
                  end;
                Result:=True;
              end;

            const
              ExpectedVersion = 2;
            var
              Version, SubsectionSize, SaveSectionSize: uint32;
              SubsectionType: Byte;
              SaveSectionStart: LongInt;
            begin
              Result:=False;
              if not ReadUleb32(Version) then
                begin
                  InputError('Error reading the version of the ''linking'' section');
                  exit;
                end;
              if Version<>ExpectedVersion then
                begin
                  InputError('The ''linking'' section has an unsupported version (expected version ' + tostr(ExpectedVersion) + ', got version ' + tostr(Version) + ')');
                  exit;
                end;
              while AReader.Pos<(SectionStart+SectionSize) do
                begin
                  if not read(SubsectionType, 1) then
                    begin
                      InputError('Error reading subsection type in the ''linking'' section');
                      exit;
                    end;
                  if not ReadUleb32(SubsectionSize) then
                    begin
                      InputError('Error reading subsection size in the ''linking'' section');
                      exit;
                    end;
                  if (AReader.Pos+SubsectionSize)>(SectionStart+SectionSize) then
                    begin
                      InputError('Subsection size exceeds bounds of its parent ''linking'' section');
                      exit;
                    end;
                  SaveSectionStart:=SectionStart;
                  SaveSectionSize:=SectionSize;
                  SectionStart:=AReader.Pos;
                  SectionSize:=SubsectionSize;
                  case SubsectionType of
                    Byte(WASM_SEGMENT_INFO):
                      if not ReadSegmentInfo then
                        begin
                          InputError('Error reading the WASM_SEGMENT_INFO subsection of the ''linking'' section');
                          exit;
                        end;
                    Byte(WASM_SYMBOL_TABLE):
                      if not ReadSymbolTable then
                        begin
                          InputError('Error reading the WASM_SYMBOL_TABLE subsection of the ''linking'' section');
                          exit;
                        end;
                    else
                      begin
                        InputError('Unsupported ''linking'' section subsection type ' + tostr(SubsectionType));
                        exit;
                      end;
                  end;
                  AReader.Seek(SectionStart+SectionSize);
                  SectionStart:=SaveSectionStart;
                  SectionSize:=SaveSectionSize;
                end;
              result:=True;
            end;

          function ReadProducersSection: Boolean;
            begin
              Result:=False;
            end;

          function ReadTargetFeaturesSection: Boolean;
            begin
              Result:=False;
            end;

          function ReadDebugSection(const SectionName: string; SectionType: TWasmCustomDebugSectionType): Boolean;
            var
              ObjSec: TObjSection;
            begin
              Result:=False;
              if DebugSectionIndex[SectionType]<>-1 then
                begin
                  InputError('Duplicated debug section: ' + SectionName);
                  exit;
                end;
              DebugSectionIndex[SectionType]:=SectionIndex;
              ObjSec:=ObjData.createsection(SectionName,1,[oso_Data,oso_debug],false);
              ObjSec.DataPos:=AReader.Pos;
              ObjSec.Size:=SectionStart+SectionSize-AReader.Pos;
              Result:=True;
            end;

          const
            RelocationSectionPrefix = 'reloc.';
          var
            SectionName: ansistring;
          begin
            Result:=False;
            ReadName(SectionName);
            if Copy(SectionName,1,Length(RelocationSectionPrefix)) = RelocationSectionPrefix then
              begin
                if not ReadRelocationSection then
                  begin
                    InputError('Error reading the relocation section ''' + SectionName + '''');
                    exit;
                  end;
              end
            else
              case SectionName of
                'linking':
                  if not ReadLinkingSection then
                    begin
                      InputError('Error reading the ''linking'' section');
                      exit;
                    end;
                'producers':
                  Result:=ReadProducersSection;
                'target_features':
                  Result:=ReadTargetFeaturesSection;
                '.debug_frame':
                  if not ReadDebugSection(SectionName, wcstDebugFrame) then
                    begin
                      InputError('Error reading section ' + SectionName);
                      exit;
                    end;
                '.debug_info':
                  if not ReadDebugSection(SectionName, wcstDebugInfo) then
                    begin
                      InputError('Error reading section ' + SectionName);
                      exit;
                    end;
                '.debug_line':
                  if not ReadDebugSection(SectionName, wcstDebugLine) then
                    begin
                      InputError('Error reading section ' + SectionName);
                      exit;
                    end;
                '.debug_abbrev':
                  if not ReadDebugSection(SectionName, wcstDebugAbbrev) then
                    begin
                      InputError('Error reading section ' + SectionName);
                      exit;
                    end;
                '.debug_aranges':
                  if not ReadDebugSection(SectionName, wcstDebugAranges) then
                    begin
                      InputError('Error reading section ' + SectionName);
                      exit;
                    end;
                '.debug_ranges':
                  if not ReadDebugSection(SectionName, wcstDebugRanges) then
                    begin
                      InputError('Error reading section ' + SectionName);
                      exit;
                    end;
                '.debug_str':
                  if not ReadDebugSection(SectionName, wcstDebugStr) then
                    begin
                      InputError('Error reading section ' + SectionName);
                      exit;
                    end;
                else
                  InputError('Unsupported custom section: ''' + SectionName + '''');
              end;
            Result:=True;
          end;

        function ReadTypeSection: Boolean;
          var
            FuncTypesCount, ParamsCount, ResultsCount: uint32;
            FuncTypeId, WasmTypeId: Byte;
            i, j: Integer;
            wbt: TWasmBasicType;
          begin
            Result:=False;
            if TypeSectionRead then
              begin
                InputError('Type section is duplicated');
                exit;
              end;
            TypeSectionRead:=True;
            if not ReadUleb32(FuncTypesCount) then
              begin
                InputError('Error reading the func types count');
                exit;
              end;
            SetLength(FFuncTypes,FuncTypesCount);
            for i:=0 to FuncTypesCount - 1 do
              begin
                FFuncTypes[i]:=TWasmFuncType.Create([],[]);
                if not AReader.read(FuncTypeId,1) then
                  begin
                    InputError('Error reading the function type identifier');
                    exit;
                  end;
                if FuncTypeId<>$60 then
                  begin
                    InputError('Incorrect function type identifier (expected $60, got $' + HexStr(FuncTypeId,2) + ')');
                    exit;
                  end;
                if not ReadUleb32(ParamsCount) then
                  begin
                    InputError('Error reading the function parameters count');
                    exit;
                  end;
                for j:=0 to ParamsCount-1 do
                  begin
                    if not AReader.read(WasmTypeId,1) then
                      begin
                        InputError('Error reading a function parameter basic type');
                        exit;
                      end;
                    if not decode_wasm_basic_type(WasmTypeId,wbt) then
                      begin
                        InputError('Unknown function parameter basic type: $' + HexStr(WasmTypeId,2));
                        exit;
                      end;
                    FFuncTypes[i].add_param(wbt);
                  end;
                if not ReadUleb32(ResultsCount) then
                  begin
                    InputError('Error reading the function results count');
                    exit;
                  end;
                for j:=0 to ResultsCount-1 do
                  begin
                    if not AReader.read(WasmTypeId,1) then
                      begin
                        InputError('Error reading a function result basic type');
                        exit;
                      end;
                    if not decode_wasm_basic_type(WasmTypeId,wbt) then
                      begin
                        InputError('Unknown function result basic type: $' + HexStr(WasmTypeId,2));
                        exit;
                      end;
                    FFuncTypes[i].add_result(wbt);
                  end;
              end;
            if AReader.Pos<>(SectionStart+SectionSize) then
              begin
                InputError('Unexpected type section size');
                exit;
              end;
            Result:=true;
          end;

        function ReadImportSection: Boolean;
          var
            ImportsCount: uint32;
            i: Integer;
            ModName, Name: ansistring;
            ImportType, TableElemTyp, TableLimitsKind, MemoryLimitsKind,
            GlobalType, GlobalMutabilityType: Byte;
          begin
            Result:=False;
            if ImportSectionRead then
              begin
                InputError('Import section is duplicated');
                exit;
              end;
            ImportSectionRead:=True;
            if not ReadUleb32(ImportsCount) then
              begin
                InputError('Error reading the imports count');
                exit;
              end;
            for i:=0 to ImportsCount-1 do
              begin
                if not ReadName(ModName) then
                  begin
                    InputError('Error reading import module name');
                    exit;
                  end;
                if not ReadName(Name) then
                  begin
                    InputError('Error import name');
                    exit;
                  end;
                if not AReader.Read(ImportType,1) then
                  begin
                    InputError('Error reading import type');
                    exit;
                  end;
                case ImportType of
                  $00:  { func }
                    begin
                      Inc(FuncTypeImportsCount);
                      SetLength(FuncTypes,FuncTypeImportsCount);
                      with FuncTypes[FuncTypeImportsCount-1] do
                        begin
                          IsImport:=True;
                          ImportName:=Name;
                          ImportModName:=ModName;
                          if not ReadUleb32(typidx) then
                            begin
                              InputError('Error reading type index for func import');
                              exit;
                            end;
                          if typidx>high(FFuncTypes) then
                            begin
                              InputError('Type index in func import exceeds bounds of the types table');
                              exit;
                            end;
                        end;
                    end;
                  $01:  { table }
                    begin
                      Inc(TableTypeImportsCount);
                      SetLength(TableTypes,TableTypeImportsCount);
                      with TableTypes[TableTypeImportsCount-1] do
                        begin
                          IsImport:=True;
                          ImportName:=Name;
                          ImportModName:=ModName;
                          if not AReader.read(TableElemTyp,1) then
                            begin
                              InputError('Error reading table element type for table import');
                              exit;
                            end;
                          if not decode_wasm_basic_type(TableElemTyp,reftype) then
                            begin
                              InputError('Invalid table element type for table import: $' + HexStr(TableElemTyp,2));
                              exit;
                            end;
                          if not (reftype in WasmReferenceTypes) then
                            begin
                              InputError('Table element type for table import must be a reference type');
                              exit;
                            end;
                          if not AReader.read(TableLimitsKind,1) then
                            begin
                              InputError('Error reading table limits kind for table import');
                              exit;
                            end;
                          case TableLimitsKind of
                            $00:
                              begin
                                limits.HasMax:=False;
                                limits.Max:=high(limits.Max);
                                if not ReadUleb32(limits.min) then
                                  begin
                                    InputError('Error reading table limits min for table import');
                                    exit;
                                  end;
                              end;
                            $01:
                              begin
                                limits.HasMax:=True;
                                if not ReadUleb32(limits.min) then
                                  begin
                                    InputError('Error reading table limits min for table import');
                                    exit;
                                  end;
                                if not ReadUleb32(limits.max) then
                                  begin
                                    InputError('Error reading table limits max for table import');
                                    exit;
                                  end;
                                if limits.min>limits.max then
                                  begin
                                    InputError('Table limits min exceed table limits max in table import');
                                    exit;
                                  end;
                              end;
                            else
                              begin
                                InputError('Unsupported table limits kind for table import: $' + HexStr(TableLimitsKind,2));
                                exit;
                              end;
                          end;
                        end;
                    end;
                  $02:  { mem }
                    begin
                      Inc(MemTypeImportsCount);
                      SetLength(MemTypes,MemTypeImportsCount);
                      with MemTypes[MemTypeImportsCount-1] do
                        begin
                          IsImport:=True;
                          ImportName:=Name;
                          ImportModName:=ModName;
                          if not AReader.read(MemoryLimitsKind,1) then
                            begin
                              InputError('Error reading memory limits kind for memory import');
                              exit;
                            end;
                          case MemoryLimitsKind of
                            $00:
                              begin
                                limits.HasMax:=False;
                                limits.Max:=high(limits.Max);
                                if not ReadUleb32(limits.min) then
                                  begin
                                    InputError('Error reading memory limits min for memory import');
                                    exit;
                                  end;
                              end;
                            $01:
                              begin
                                limits.HasMax:=True;
                                if not ReadUleb32(limits.min) then
                                  begin
                                    InputError('Error reading memory limits min for memory import');
                                    exit;
                                  end;
                                if not ReadUleb32(limits.max) then
                                  begin
                                    InputError('Error reading memory limits max for memory import');
                                    exit;
                                  end;
                                if limits.Min>limits.Max then
                                  begin
                                    InputError('Memory limits min exceed memory limits max in memory import');
                                    exit;
                                  end;
                              end;
                            else
                              begin
                                InputError('Unsupported memory limits kind for memory import: $' + HexStr(MemoryLimitsKind,2));
                                exit;
                              end;
                          end;
                        end;
                    end;
                  $03:  { global }
                    begin
                      Inc(GlobalTypeImportsCount);
                      SetLength(GlobalTypes,GlobalTypeImportsCount);
                      with GlobalTypes[GlobalTypeImportsCount-1] do
                        begin
                          IsImport:=True;
                          ImportName:=Name;
                          ImportModName:=ModName;
                          if not AReader.read(GlobalType,1) then
                            begin
                              InputError('Error reading global type for global import');
                              exit;
                            end;
                          if not decode_wasm_basic_type(GlobalType,valtype) then
                            begin
                              InputError('Unsupported global type for global import: ' + HexStr(GlobalType,2));
                              exit;
                            end;
                          if not AReader.read(GlobalMutabilityType,1) then
                            begin
                              InputError('Error reading global mutability flag for global import');
                              exit;
                            end;
                          case GlobalMutabilityType of
                            $00:
                              IsMutable:=False;
                            $01:
                              IsMutable:=True;
                            else
                              begin
                                InputError('Unknown global mutability flag for global import: $' + HexStr(GlobalMutabilityType,2));
                                exit;
                              end;
                          end;
                        end;
                    end;
                  $04: { tag }
                    begin
                      Inc(TagTypeImportsCount);
                      SetLength(TagTypes,TagTypeImportsCount);
                      with TagTypes[TagTypeImportsCount-1] do
                        begin
                          IsImport:=True;
                          ImportName:=Name;
                          ImportModName:=ModName;
                          if not Read(TagAttr,1) then
                            begin
                              InputError('Error reading import tag attribute');
                              exit;
                            end;
                          if not ReadUleb32(TagTypeIdx) then
                            begin
                              InputError('Error reading import tag type index');
                              exit;
                            end;
                          if TagTypeIdx>high(FFuncTypes) then
                            begin
                              InputError('Type index in tag import exceeds bounds of the types table');
                              exit;
                            end;
                        end;
                    end;
                  else
                    begin
                      InputError('Unknown import type: $' + HexStr(ImportType,2));
                      exit;
                    end;
                end;
              end;
            if AReader.Pos<>(SectionStart+SectionSize) then
              begin
                InputError('Unexpected import section size');
                exit;
              end;
            Result:=true;
          end;

        function ReadFunctionSection: Boolean;
          var
            FunctionsCount: uint32;
            i: Integer;
          begin
            Result:=False;
            if FunctionSectionRead then
              begin
                InputError('Function section is duplicated');
                exit;
              end;
            FunctionSectionRead:=True;
            if not ReadUleb32(FunctionsCount) then
              begin
                InputError('Error reading the functions count');
                exit;
              end;
            SetLength(FuncTypes, FuncTypeImportsCount + FunctionsCount);
            for i:=0 to FunctionsCount-1 do
              with FuncTypes[i + FuncTypeImportsCount] do
                begin
                  IsImport:=False;
                  if not ReadUleb32(typidx) then
                    begin
                      InputError('Error reading type index for function');
                      exit;
                    end;
                  if typidx>high(FFuncTypes) then
                    begin
                      InputError('Type index in the function section exceeds bounds of the types table');
                      exit;
                    end;
                end;
            if AReader.Pos<>(SectionStart+SectionSize) then
              begin
                InputError('Unexpected function section size');
                exit;
              end;
            Result:=true;
          end;

        function ReadGlobalSection: Boolean;

          function ParseExpr(out Init: TGlobalInitializer): Boolean;
            var
              B, B2: Byte;
              tmpU32: UInt32;
              tmpU64: UInt64;
            begin
              Result:=False;
              repeat
                if not Read(B, 1) then
                  exit;
                case B of
                  $0B:  { end }
                    ;
                  $41:  { i32.const }
                    begin
                      Init.typ:=wbt_i32;
                      if not ReadSleb32(Init.init_i32) then
                        exit;
                    end;
                  $42:  { i64.const }
                    begin
                      Init.typ:=wbt_i64;
                      if not ReadSleb(Init.init_i64) then
                        exit;
                    end;
                  $43:  { f32.const }
                    begin
                      Init.typ:=wbt_f32;
                      if not Read(tmpU32, 4) then
                        exit;
{$ifdef FPC_BIG_ENDIAN}
                      tmpU32:=SwapEndian(tmpU32);
{$endif FPC_BIG_ENDIAN}
                      Move(tmpU32,Init.init_f32,4);
                    end;
                  $44:  { f64.const }
                    begin
                      Init.typ:=wbt_f64;
                      if not Read(tmpU64, 8) then
                        exit;
{$ifdef FPC_BIG_ENDIAN}
                      tmpU64:=SwapEndian(tmpU64);
{$endif FPC_BIG_ENDIAN}
                      Move(tmpU64,Init.init_f64,8);
                    end;
                  $D0:  { ref.null }
                    begin
                      if not Read(B2, 1) then
                        exit;
                      if not decode_wasm_basic_type(B2, Init.typ) then
                        exit;
                      if not (Init.typ in WasmReferenceTypes) then
                        exit;
                    end;
                  else
                    begin
                      InputError('Unsupported opcode in global initializer');
                      exit;
                    end;
                end;
              until b = $0B;
              Result:=True;
            end;

          var
            GlobalsCount: uint32;
            i: Integer;
            vt: Byte;
            mut: Byte;
          begin
            Result:=False;
            if GlobalSectionRead then
              begin
                InputError('Global section is duplicated');
                exit;
              end;
            GlobalSectionRead:=True;
            if not ReadUleb32(GlobalsCount) then
              begin
                InputError('Error reading the globals count from the global section');
                exit;
              end;
            SetLength(GlobalTypes,Length(GlobalTypes)+GlobalsCount);
            for i:=0 to GlobalsCount-1 do
              with GlobalTypes[i + GlobalTypeImportsCount] do
                begin
                  if not read(vt,1) then
                    begin
                      InputError('Error reading the type of a global from the global section');
                      exit;
                    end;
                  if not decode_wasm_basic_type(vt,valtype) then
                    begin
                      InputError('Unsupported type of global in the global section');
                      exit;
                    end;
                  if not read(mut,1) then
                    begin
                      InputError('Error reading the mutability flag of a global in the global section');
                      exit;
                    end;
                  case mut of
                    $00:
                      IsMutable:=False;
                    $01:
                      IsMutable:=True;
                    else
                      begin
                        InputError('Unsupported value (' + tostr(mut) + ') for the mutability flag of a global in the global section');
                        exit;
                      end;
                  end;
                  if not ParseExpr(GlobalInit) then
                    begin
                      InputError('Error parsing the global initializer expression in the global section');
                      exit;
                    end;
                  if GlobalInit.typ<>valtype then
                    begin
                      InputError('Initializer expression for global produces a type, which does not match the type of the global');
                      exit;
                    end;
                end;
            if AReader.Pos<>(SectionStart+SectionSize) then
              begin
                InputError('Unexpected global section size');
                exit;
              end;
            Result:=True;
          end;

        function ReadExportSection: Boolean;
          var
            ExportsCount, FuncIdx, TableIdx, MemIdx, GlobalIdx, TagIdx: uint32;
            i: Integer;
            Name: ansistring;
            ExportType: Byte;
          begin
            Result:=False;
            if ExportSectionRead then
              begin
                InputError('Export section is duplicated');
                exit;
              end;
            ExportSectionRead:=True;
            if not ReadUleb32(ExportsCount) then
              begin
                InputError('Error reading the exports count from the export section');
                exit;
              end;
            for i:=0 to ExportsCount-1 do
              begin
                if not ReadName(Name) then
                  begin
                    InputError('Error reading an export name from the export section');
                    exit;
                  end;
                if not Read(ExportType,1) then
                  begin
                    InputError('Error reading an export type from the export section');
                    exit;
                  end;
                case ExportType of
                  $00:  { func }
                    begin
                      if not ReadUleb32(FuncIdx) then
                        begin
                          InputError('Error reading a func index from the export section');
                          exit;
                        end;
                      if FuncIdx>high(FuncTypes) then
                        begin
                          InputError('Func index too high in the export section');
                          exit;
                        end;
                      with FuncTypes[FuncIdx] do
                        begin
                          IsExported:=True;
                          ExportName:=Name;
                        end;
                    end;
                  $01:  { table }
                    begin
                      if not ReadUleb32(TableIdx) then
                        begin
                          InputError('Error reading a table index from the export section');
                          exit;
                        end;
                      if TableIdx>high(TableTypes) then
                        begin
                          InputError('Table index too high in the export section');
                          exit;
                        end;
                      with TableTypes[TableIdx] do
                        begin
                          IsExported:=True;
                          ExportName:=Name;
                        end;
                    end;
                  $02:  { mem }
                    begin
                      if not ReadUleb32(MemIdx) then
                        begin
                          InputError('Error reading a mem index from the export section');
                          exit;
                        end;
                      if MemIdx>high(MemTypes) then
                        begin
                          InputError('Mem index too high in the export section');
                          exit;
                        end;
                      with MemTypes[MemIdx] do
                        begin
                          IsExported:=True;
                          ExportName:=Name;
                        end;
                    end;
                  $03:  { global }
                    begin
                      if not ReadUleb32(GlobalIdx) then
                        begin
                          InputError('Error reading a global index from the export section');
                          exit;
                        end;
                      if GlobalIdx>high(GlobalTypes) then
                        begin
                          InputError('Global index too high in the export section');
                          exit;
                        end;
                      with GlobalTypes[GlobalIdx] do
                        begin
                          IsExported:=True;
                          ExportName:=Name;
                        end;
                    end;
                  $04:  { tag }
                    begin
                      if not ReadUleb32(TagIdx) then
                        begin
                          InputError('Error reading a tag index from the export section');
                          exit;
                        end;
                      if TagIdx>high(TagTypes) then
                        begin
                          InputError('Tag index too high in the export section');
                          exit;
                        end;
                      with TagTypes[TagIdx] do
                        begin
                          IsExported:=True;
                          ExportName:=Name;
                        end;
                    end;
                  else
                    begin
                      InputError('Unsupported export type in the export section: ' + tostr(ExportType));
                      exit;
                    end;
                end;
              end;
            if AReader.Pos<>(SectionStart+SectionSize) then
              begin
                InputError('Unexpected export section size');
                exit;
              end;
            Result:=True;
          end;

        function ReadElementSection: Boolean;
          begin
            Result:=False;
            if ElementSectionRead then
              begin
                InputError('Element section is duplicated');
                exit;
              end;
            ElementSectionRead:=True;
            { We skip the element section for now }
            { TODO: implement reading it (and linking of tables) }
            Result:=True;
          end;

        function ReadTagSection: Boolean;
          var
            TagCount: uint32;
            i: Integer;
          begin
            Result:=False;
            if TagSectionRead then
              begin
                InputError('Tag section is duplicated');
                exit;
              end;
            TagSectionRead:=True;
            if not ReadUleb32(TagCount) then
              begin
                InputError('Error reading the tag count from the tag section');
                exit;
              end;
            SetLength(TagTypes,Length(TagTypes)+TagCount);
            for i:=0 to TagCount-1 do
              with TagTypes[i + TagTypeImportsCount] do
                begin
                  if not Read(TagAttr,1) then
                    begin
                      InputError('Error reading tag attribute');
                      exit;
                    end;
                  if not ReadUleb32(TagTypeIdx) then
                    begin
                      InputError('Error reading tag type index');
                      exit;
                    end;
                  if TagTypeIdx>high(FFuncTypes) then
                    begin
                      InputError('Type index in tag import exceeds bounds of the types table');
                      exit;
                    end;
                end;
            if AReader.Pos<>(SectionStart+SectionSize) then
              begin
                InputError('Unexpected tag section size');
                exit;
              end;
            Result:=True;
          end;

        function ReadCodeSection: Boolean;
          var
            CodeEntriesCount: uint32;
            i: Integer;
          begin
            Result:=False;
            if CodeSectionRead then
              begin
                InputError('Code section is duplicated');
                exit;
              end;
            CodeSectionRead:=True;
            CodeSectionIndex:=SectionIndex;
            if not ReadUleb32(CodeEntriesCount) then
              begin
                InputError('Error reading the code entries cound from the code section');
                exit;
              end;
            if CodeEntriesCount <> (Length(FuncTypes) - FuncTypeImportsCount) then
              begin
                InputError('Code segment count in the code section does not match the function definition count in the function section');
                exit;
              end;
            SetLength(CodeSegments,CodeEntriesCount);
            for i:=0 to CodeEntriesCount-1 do
              with CodeSegments[i] do
                begin
                  if not ReadUleb32(CodeSize) then
                    begin
                      InputError('Error reading the code size of an entry in the code section');
                      exit;
                    end;
                  if (AReader.Pos+CodeSize)>(SectionStart+SectionSize) then
                    begin
                      InputError('Code segment exceeds the bounds of the code section');
                      exit;
                    end;
                  DataPos:=AReader.Pos;
                  CodeSectionOffset:=AReader.Pos-SectionStart;
                  AReader.Seek(AReader.Pos+CodeSize);
                end;
            if AReader.Pos<>(SectionStart+SectionSize) then
              begin
                InputError('Unexpected code section size');
                exit;
              end;
            Result:=true;
          end;

        function ReadDataSection: Boolean;

          function ReadExpr(out ExprV: int32): Boolean;
            var
              b: Byte;
            begin
              Result:=False;
              if not Read(b,1) then
                exit;
              if b<>$41 then
                begin
                  InputError('Only i32.const expressions supported');
                  exit;
                end;
              if not ReadSleb32(ExprV) then
                exit;
              if not Read(b,1) then
                exit;
              if b<>$0B then
                begin
                  InputError('Only single const expressions supported');
                  exit;
                end;
              Result:=True;
            end;

          var
            DataCount: uint32;
            DataType: Byte;
            i: Integer;
          begin
            Result:=False;
            if DataSectionRead then
              begin
                InputError('Data section is duplicated');
                exit;
              end;
            DataSectionRead:=True;
            DataSectionIndex:=SectionIndex;
            if not ReadUleb32(DataCount) then
              begin
                InputError('Error reading the data entries count from the data section');
                exit;
              end;
            if DataCountSectionRead then
              begin
                if Length(DataSegments)<>DataCount then
                  begin
                    InputError('Data entries count in the data section do not match the number, specified in the data count section');
                    exit;
                  end;
              end
            else
              SetLength(DataSegments,DataCount);
            for i:=0 to DataCount-1 do
              with DataSegments[i] do
                begin
                  if not read(DataType, 1) then
                    begin
                      InputError('Error reading data type of segment from the data section');
                      exit;
                    end;
                  case DataType of
                    0:
                      begin
                        Active:=True;
                        MemIdx:=0;
                        if not ReadExpr(Offset) then
                          begin
                            InputError('Error reading memory offset of segment from the data section');
                            exit;
                          end;
                      end;
                    1:
                      Active:=False;
                    2:
                      begin
                        Active:=True;
                        if not ReadUleb32(MemIdx) then
                          begin
                            InputError('Error reading MemIdx of segment from the data section');
                            exit;
                          end;
                        if not ReadExpr(Offset) then
                          begin
                            InputError('Error reading memory offset of segment from the data section');
                            exit;
                          end;
                      end;
                    else
                      begin
                        InputError('Unsupported data type of segment in the data section: ' + tostr(DataType));
                        exit;
                      end;
                  end;
                  if MemIdx<>0 then
                    begin
                      InputError('Memory index other than 0 not supported (got ' + tostr(MemIdx) + ')');
                      exit;
                    end;
                  if not Active then
                    begin
                      InputError('Passive memory segments not supported');
                      exit;
                    end;
                  if not ReadUleb32(Len) then
                    begin
                      InputError('Error reading data segment length');
                      exit;
                    end;
                  if (AReader.Pos+Len)>(SectionStart+SectionSize) then
                    begin
                      InputError('Data segment exceeds the bounds of the data section');
                      exit;
                    end;
                  DataPos:=AReader.Pos;
                  DataSectionOffset:=AReader.Pos-SectionStart;
                  AReader.Seek(AReader.Pos+Len);
                end;
            if AReader.Pos<>(SectionStart+SectionSize) then
              begin
                InputError('Unexpected data section size');
                exit;
              end;
            Result:=true;
          end;

        function ReadDataCountSection: Boolean;
          var
            DataCount: uint32;
          begin
            Result:=False;
            if DataCountSectionRead then
              begin
                InputError('Data count section is duplicated');
                exit;
              end;
            DataCountSectionRead:=True;
            if DataSectionRead then
              begin
                InputError('The data count section must occur before the data section');
                exit;
              end;
            if not ReadUleb32(DataCount) then
              begin
                InputError('Error reading the data count from the data count section');
                exit;
              end;
            if AReader.Pos<>(SectionStart+SectionSize) then
              begin
                InputError('Unexpected data count section size');
                exit;
              end;
            SetLength(DataSegments, DataCount);
            Result:=true;
          end;

        begin
          Result:=False;
          Inc(SectionIndex);
          if not AReader.read(SectionId,1) then
            begin
              InputError('Error reading section ID');
              exit;
            end;
          CheckSectionBounds:=false;
          if not ReadUleb32(SectionSize) then
            begin
              InputError('Error reading section size');
              exit;
            end;
          if (AReader.Pos+SectionSize)>AReader.size then
            begin
              InputError('Section exceeds beyond the end of file');
              exit;
            end;
          SectionStart:=AReader.Pos;
          CheckSectionBounds:=true;
          case SectionId of
            Byte(wsiCustom):
              if not ReadCustomSection then
                begin
                  InputError('Error encountered, while reading a custom section');
                  exit;
                end;
            Byte(wsiType):
              if not ReadTypeSection then
                begin
                  InputError('Error reading the type section');
                  exit;
                end;
            Byte(wsiImport):
              if not ReadImportSection then
                begin
                  InputError('Error reading the import section');
                  exit;
                end;
            Byte(wsiFunction):
              if not ReadFunctionSection then
                begin
                  InputError('Error reading the function section');
                  exit;
                end;
            Byte(wsiGlobal):
              if not ReadGlobalSection then
                begin
                  InputError('Error reading the global section');
                  exit;
                end;
            Byte(wsiExport):
              if not ReadExportSection then
                begin
                  InputError('Error reading the export section');
                  exit;
                end;
            Byte(wsiElement):
              if not ReadElementSection then
                begin
                  InputError('Error reading the element section');
                  exit;
                end;
            Byte(wsiTag):
              if not ReadTagSection then
                begin
                  InputError('Error reading the tag section');
                  exit;
                end;
            Byte(wsiCode):
              if not ReadCodeSection then
                begin
                  InputError('Error reading the code section');
                  exit;
                end;
            Byte(wsiData):
              if not ReadDataSection then
                begin
                  InputError('Error reading the data section');
                  exit;
                end;
            Byte(wsiDataCount):
              begin
                if not ReadDataCountSection then
                  begin
                    InputError('Error reading the data count section');
                    exit;
                  end;
              end
            else
              begin
                InputError('Unknown section: ' + ToStr(SectionId));
                exit;
              end;
          end;
          if SectionSize>0 then
            AReader.seek(SectionStart+SectionSize);
          Result:=True;
        end;

        function FindCodeSegment(Ofs: uint32): Integer;
          var
            L, R, M: Integer;
          begin
            L:=Low(CodeSegments);
            R:=High(CodeSegments);
            while L<=R do
              begin
                M:=(L+R) div 2;
                if (CodeSegments[M].CodeSectionOffset+CodeSegments[M].CodeSize-1) < Ofs then
                  L:=M+1
                else if CodeSegments[M].CodeSectionOffset > Ofs then
                  R:=M-1
                else
                  begin
                    Result:=M;
                    exit;
                  end;
              end;
            Result:=-1;
          end;

        function FindDataSegment(Ofs: uint32): Integer;
          var
            L, R, M: Integer;
          begin
            L:=Low(DataSegments);
            R:=High(DataSegments);
            while L<=R do
              begin
                M:=(L+R) div 2;
                if (DataSegments[M].DataSectionOffset+DataSegments[M].Len-1) < Ofs then
                  L:=M+1
                else if DataSegments[M].DataSectionOffset > Ofs then
                  R:=M-1
                else
                  begin
                    Result:=M;
                    exit;
                  end;
              end;
            Result:=-1;
          end;

      var
        ModuleMagic: array [0..3] of Byte;
        ModuleVersion: array [0..3] of Byte;
        i, j, FirstCodeSegmentIdx, FirstDataSegmentIdx, SegI: Integer;
        CurrSec, ObjSec: TObjSection;
        BaseSectionOffset: UInt32;
        ObjReloc: TWasmObjRelocation;
        ds: TWasmCustomDebugSectionType;
      begin
        FReader:=AReader;
        InputFileName:=AReader.FileName;
        objdata:=CObjData.Create(InputFileName);
        result:=false;
        CodeSegments:=nil;
        DataSegments:=nil;
        SymbolTable:=nil;
        RelocationTable:=nil;
        SetLength(RelocationTable,2+(Ord(High(TWasmCustomDebugSectionType))-Ord(Low(TWasmCustomDebugSectionType))+1));
        FuncTypes:=nil;
        FuncTypeImportsCount:=0;
        TableTypes:=nil;
        TableTypeImportsCount:=0;
        MemTypes:=nil;
        MemTypeImportsCount:=0;
        GlobalTypes:=nil;
        GlobalTypeImportsCount:=0;
        TagTypes:=nil;
        TagTypeImportsCount:=0;

        if not AReader.read(ModuleMagic,4) then
          exit;
        for i:=0 to 3 do
          if ModuleMagic[i]<>WasmModuleMagic[i] then
            exit;
        if not AReader.read(ModuleVersion,4) then
          exit;
        for i:=0 to 3 do
          if ModuleVersion[i]<>WasmVersion[i] then
            exit;
        while AReader.Pos<AReader.size do
          if not ReadSection then
            exit;

        { fill the code segment names }
        for i:=low(SymbolTable) to high(SymbolTable) do
          with SymbolTable[i] do
            if (SymKind=SYMTAB_FUNCTION) and ((SymFlags and WASM_SYM_UNDEFINED)=0) then
              begin
                if FuncTypes[SymIndex].IsImport then
                  begin
                    InputError('WASM_SYM_UNDEFINED not set on a SYMTAB_FUNCTION symbol, that is an import');
                    exit;
                  end;
                if (SymFlags and WASM_SYM_EXPLICIT_NAME)=0 then
                  begin
                    with CodeSegments[SymIndex-FuncTypeImportsCount] do
                      begin
                        SegName:='.text.n_'+SymName;
                        SegIsExported:=FuncTypes[SymIndex].IsExported;
                      end;
                  end;
              end;

        { create segments }
        FirstCodeSegmentIdx:=ObjData.ObjSectionList.Count;
        for i:=low(CodeSegments) to high(CodeSegments) do
          with CodeSegments[i] do
            begin
              if SegName='' then
                begin
                  InputError('Code section ' + tostr(i) + ' does not have a main symbol defined in the symbol table');
                  exit;
                end;
              if SegIsExported or not (cs_link_smart in current_settings.globalswitches) then
                CurrSec:=ObjData.createsection(SegName,1,[oso_executable,oso_Data,oso_load,oso_keep],false)
              else
                CurrSec:=ObjData.createsection(SegName,1,[oso_executable,oso_Data,oso_load],false);
              CurrSec.DataPos:=DataPos;
              CurrSec.Size:=CodeSize;
            end;
        FirstDataSegmentIdx:=ObjData.ObjSectionList.Count;
        for i:=low(DataSegments) to high(DataSegments) do
          with DataSegments[i] do
            if Active then
              begin
                if not (cs_link_smart in current_settings.globalswitches) then
                  CurrSec:=ObjData.createsection(SegName,1 shl SegAlignment,[oso_Data,oso_load,oso_write,oso_keep],false)
                else
                  CurrSec:=ObjData.createsection(SegName,1 shl SegAlignment,[oso_Data,oso_load,oso_write],false);
                CurrSec.DataPos:=DataPos;
                CurrSec.MemPos:=Offset;
                CurrSec.Size:=Len;
              end;
        ReadSectionContent(ObjData);

        for i:=low(SymbolTable) to high(SymbolTable) do
          with SymbolTable[i] do
            case SymKind of
              SYMTAB_DATA:
                if (SymFlags and WASM_SYM_UNDEFINED)<>0 then
                  begin
                    objsym:=TWasmObjSymbol(ObjData.CreateSymbol(SymName));
                    objsym.bind:=AB_EXTERNAL;
                    if (SymFlags and WASM_SYM_TLS)<>0 then
                      begin
                        objsym.typ:=AT_TLS;
                        objsym.TlsGlobalSym:=TWasmObjSymbol(ObjData.CreateSymbol('GOT.mem.'+SymName));
                        objsym.TlsGlobalSym.TlsDataSym:=objsym;
                        objsym.TlsGlobalSym.bind:=AB_EXTERNAL;
                        objsym.TlsGlobalSym.typ:=AT_WASM_GLOBAL;
                        objsym.TlsGlobalSym.objsection:=nil;
                        objsym.TlsGlobalSym.offset:=0;
                        objsym.TlsGlobalSym.size:=1;
                        objsym.TlsGlobalSym.LinkingData.GlobalType:=wbt_i32;
                        objsym.TlsGlobalSym.LinkingData.GlobalIsMutable:=true;
                      end
                    else
                      objsym.typ:=AT_DATA;
                    objsym.objsection:=nil;
                    objsym.offset:=0;
                    objsym.size:=0;
                  end
                else
                  begin
                    objsym:=TWasmObjSymbol(ObjData.CreateSymbol(SymName));
                    if (SymFlags and WASM_SYM_BINDING_LOCAL)<> 0 then
                      objsym.bind:=AB_LOCAL
                    else
                      objsym.bind:=AB_GLOBAL;
                    if (SymFlags and WASM_SYM_TLS)<>0 then
                      begin
                        objsym.typ:=AT_TLS;
                        objsym.TlsGlobalSym:=TWasmObjSymbol(ObjData.CreateSymbol('GOT.mem.'+SymName));
                        objsym.TlsGlobalSym.TlsDataSym:=objsym;
                        objsym.TlsGlobalSym.bind:=objsym.bind;
                        objsym.TlsGlobalSym.typ:=AT_WASM_GLOBAL;
                        objsym.TlsGlobalSym.objsection:=ObjData.createsection('.wasm_globals.n_'+objsym.TlsGlobalSym.Name,1,[oso_Data,oso_load],true);
                        if objsym.TlsGlobalSym.objsection.Size=0 then
                          objsym.TlsGlobalSym.objsection.WriteZeros(1);
                        TWasmObjSection(objsym.TlsGlobalSym.objsection).MainFuncSymbol:=objsym.TlsGlobalSym;
                        objsym.TlsGlobalSym.offset:=0;
                        objsym.TlsGlobalSym.size:=1;
                        objsym.TlsGlobalSym.LinkingData.GlobalType:=wbt_i32;
                        objsym.TlsGlobalSym.LinkingData.GlobalIsMutable:=true;
                      end
                    else
                      objsym.typ:=AT_DATA;
                    objsym.objsection:=TObjSection(ObjData.ObjSectionList[FirstDataSegmentIdx+SymIndex]);
                    objsym.offset:=SymOffset;
                    objsym.size:=SymSize;
                  end;
              SYMTAB_FPC_CUSTOM:
                if (SymFlags and WASM_SYM_UNDEFINED)<>0 then
                  begin
                    objsym:=TWasmObjSymbol(ObjData.CreateSymbol(SymName));
                    objsym.bind:=AB_EXTERNAL;
                    if (SymFlags and WASM_SYM_TLS)<>0 then
                      internalerror(2024080702);
                    objsym.typ:=AT_DATA;
                    objsym.objsection:=nil;
                    objsym.offset:=0;
                    objsym.size:=0;
                  end
                else
                  begin
                    objsym:=TWasmObjSymbol(ObjData.CreateSymbol(SymName));
                    if (SymFlags and WASM_SYM_BINDING_LOCAL)<> 0 then
                      objsym.bind:=AB_LOCAL
                    else
                      objsym.bind:=AB_GLOBAL;
                    if (SymFlags and WASM_SYM_TLS)<>0 then
                      internalerror(2024080703);
                    objsym.typ:=AT_DATA;
                    objsym.objsection:=TObjSection(ObjData.ObjSectionList.Find(WasmCustomSectionName[SymCustomSectionType]));
                    objsym.offset:=SymOffset;
                    objsym.size:=SymSize;
                  end;
              SYMTAB_FUNCTION:
                begin
                  if (SymFlags and WASM_SYM_UNDEFINED)<>0 then
                    begin
                      if not FuncTypes[SymIndex].IsImport then
                        begin
                          InputError('WASM_SYM_UNDEFINED set on a SYMTAB_FUNCTION symbol, that is not an import');
                          exit;
                        end;
                      if (SymFlags and WASM_SYM_EXPLICIT_NAME)<>0 then
                        begin
                          objsym:=TWasmObjSymbol(ObjData.CreateSymbol(SymName));
                          objsym.bind:=AB_EXTERNAL;
                          objsym.typ:=AT_FUNCTION;
                          objsym.objsection:=nil;
                          objsym.offset:=0;
                          objsym.size:=0;
                          objsym.LinkingData.ImportModule:=FuncTypes[SymIndex].ImportModName;
                          objsym.LinkingData.ImportName:=FuncTypes[SymIndex].ImportName;
                        end
                      else
                        begin
                          if FuncTypes[SymIndex].ImportModName = 'env' then
                            objsym:=TWasmObjSymbol(ObjData.CreateSymbol(FuncTypes[SymIndex].ImportName))
                          else
                            objsym:=TWasmObjSymbol(ObjData.CreateSymbol(FuncTypes[SymIndex].ImportModName + '.' + FuncTypes[SymIndex].ImportName));
                          objsym.bind:=AB_EXTERNAL;
                          objsym.typ:=AT_FUNCTION;
                          objsym.objsection:=nil;
                          objsym.offset:=0;
                          objsym.size:=0;
                        end;
                    end
                  else
                    begin
                      objsym:=TWasmObjSymbol(ObjData.CreateSymbol(SymName));
                      objsym.bind:=AB_GLOBAL;
                      objsym.typ:=AT_FUNCTION;
                      objsym.objsection:=TObjSection(ObjData.ObjSectionList[FirstCodeSegmentIdx+SymIndex-FuncTypeImportsCount]);
                      if (SymFlags and WASM_SYM_EXPLICIT_NAME)=0 then
                        TWasmObjSection(ObjData.ObjSectionList[FirstCodeSegmentIdx+SymIndex-FuncTypeImportsCount]).MainFuncSymbol:=objsym;
                      objsym.offset:=0;
                      objsym.size:=objsym.objsection.Size;
                    end;
                  objsym.LinkingData.FuncType:=TWasmFuncType.Create(FFuncTypes[FuncTypes[SymIndex].typidx]);
                  objsym.LinkingData.IsExported:=FuncTypes[SymIndex].IsExported;
                  objsym.LinkingData.ExportName:=FuncTypes[SymIndex].ExportName;
                end;
              SYMTAB_GLOBAL:
                begin
                  if (SymFlags and WASM_SYM_UNDEFINED)<>0 then
                    begin
                      if not GlobalTypes[SymIndex].IsImport then
                        begin
                          InputError('WASM_SYM_UNDEFINED set on a SYMTAB_GLOBAL symbol, that is not an import');
                          exit;
                        end;
                      if (SymFlags and WASM_SYM_EXPLICIT_NAME)<>0 then
                        begin
                          objsym:=TWasmObjSymbol(ObjData.CreateSymbol(SymName));
                          objsym.bind:=AB_EXTERNAL;
                          objsym.typ:=AT_WASM_GLOBAL;
                          objsym.objsection:=nil;
                          objsym.offset:=0;
                          objsym.size:=1;
                          objsym.LinkingData.ImportModule:=GlobalTypes[SymIndex].ImportModName;
                          objsym.LinkingData.ImportName:=GlobalTypes[SymIndex].ImportName;
                        end
                      else
                        begin
                          if GlobalTypes[SymIndex].ImportModName = 'env' then
                            objsym:=TWasmObjSymbol(ObjData.CreateSymbol(GlobalTypes[SymIndex].ImportName))
                          else
                            objsym:=TWasmObjSymbol(ObjData.CreateSymbol(GlobalTypes[SymIndex].ImportModName + '.' + GlobalTypes[SymIndex].ImportName));
                          objsym.bind:=AB_EXTERNAL;
                          objsym.typ:=AT_WASM_GLOBAL;
                          objsym.objsection:=nil;
                          objsym.offset:=0;
                          objsym.size:=1;
                        end;
                    end
                  else
                    begin
                      if GlobalTypes[SymIndex].IsImport then
                        begin
                          InputError('WASM_SYM_UNDEFINED not set on a SYMTAB_GLOBAL symbol, that is an import');
                          exit;
                        end;
                      objsym:=TWasmObjSymbol(ObjData.CreateSymbol(SymName));
                      objsym.bind:=AB_GLOBAL;
                      objsym.typ:=AT_WASM_GLOBAL;
                      objsym.objsection:=ObjData.createsection('.wasm_globals.n_'+SymName,1,[oso_Data,oso_load],true);
                      if objsym.objsection.Size=0 then
                        objsym.objsection.WriteZeros(1);
                      if (SymFlags and WASM_SYM_EXPLICIT_NAME)=0 then
                        TWasmObjSection(objsym.objsection).MainFuncSymbol:=objsym;
                      objsym.offset:=0;
                      objsym.size:=1;
                      objsym.LinkingData.GlobalInitializer:=GlobalTypes[SymIndex].GlobalInit;
                    end;
                  objsym.LinkingData.GlobalType:=GlobalTypes[SymIndex].valtype;
                  objsym.LinkingData.GlobalIsMutable:=GlobalTypes[SymIndex].IsMutable;
                  objsym.LinkingData.IsExported:=GlobalTypes[SymIndex].IsExported;
                  objsym.LinkingData.ExportName:=GlobalTypes[SymIndex].ExportName;
                end;
              SYMTAB_SECTION:
                begin
                  for ds:=Low(DebugSectionIndex) to High(DebugSectionIndex) do
                    if DebugSectionIndex[ds]=TargetSection then
                      begin
                        ObjSec:=TWasmObjSection(ObjData.findsection(WasmCustomSectionName[ds]));
                        break;
                      end;
                  if ObjSec=nil then
                    begin
                      InputError('SYMTAB_SECTION entry points to an unsupported section');
                      exit;
                    end;
                end;
              SYMTAB_EVENT:
                begin
                  if (SymFlags and WASM_SYM_UNDEFINED)<>0 then
                    begin
                      if not TagTypes[SymIndex].IsImport then
                        begin
                          InputError('WASM_SYM_UNDEFINED set on a SYMTAB_EVENT symbol, that is not an import');
                          exit;
                        end;
                      if (SymFlags and WASM_SYM_EXPLICIT_NAME)<>0 then
                        begin
                          objsym:=TWasmObjSymbol(ObjData.CreateSymbol(SymName));
                          objsym.bind:=AB_EXTERNAL;
                          objsym.typ:=AT_WASM_EXCEPTION_TAG;
                          objsym.objsection:=nil;
                          objsym.offset:=0;
                          objsym.size:=1;
                          objsym.LinkingData.ImportModule:=TagTypes[SymIndex].ImportModName;
                          objsym.LinkingData.ImportName:=TagTypes[SymIndex].ImportName;
                        end
                      else
                        begin
                          if GlobalTypes[SymIndex].ImportModName = 'env' then
                            objsym:=TWasmObjSymbol(ObjData.CreateSymbol(GlobalTypes[SymIndex].ImportName))
                          else
                            objsym:=TWasmObjSymbol(ObjData.CreateSymbol(GlobalTypes[SymIndex].ImportModName + '.' + GlobalTypes[SymIndex].ImportName));
                          objsym.bind:=AB_EXTERNAL;
                          objsym.typ:=AT_WASM_EXCEPTION_TAG;
                          objsym.objsection:=nil;
                          objsym.offset:=0;
                          objsym.size:=1;
                        end;
                    end
                  else
                    begin
                      if TagTypes[SymIndex].IsImport then
                        begin
                          InputError('WASM_SYM_UNDEFINED not set on a SYMTAB_EVENT symbol, that is an import');
                          exit;
                        end;
                      objsym:=TWasmObjSymbol(ObjData.CreateSymbol(SymName));
                      if (symflags and WASM_SYM_BINDING_WEAK) <> 0 then
                        objsym.bind:=AB_WEAK_EXTERNAL
                      else if (symflags and WASM_SYM_BINDING_LOCAL) <> 0 then
                        objsym.bind:=AB_LOCAL
                      else
                        objsym.bind:=AB_GLOBAL;
                      objsym.typ:=AT_WASM_EXCEPTION_TAG;
                      objsym.objsection:=ObjData.createsection('.wasm_tags.n_'+SymName,1,[oso_Data,oso_load],true);
                      if objsym.objsection.Size=0 then
                        objsym.objsection.WriteZeros(1);
                      if (SymFlags and WASM_SYM_EXPLICIT_NAME)=0 then
                        TWasmObjSection(objsym.objsection).MainFuncSymbol:=objsym;
                      objsym.offset:=0;
                      objsym.size:=1;
                    end;
                  objsym.LinkingData.FuncType:=TWasmFuncType.Create(FFuncTypes[TagTypes[SymIndex].TagTypeIdx]);
                  objsym.LinkingData.IsExported:=TagTypes[SymIndex].IsExported;
                  objsym.LinkingData.ExportName:=TagTypes[SymIndex].ExportName;
                end;
              SYMTAB_TABLE:
                {TODO};
            end;

        for j:=0 to high(RelocationTable) do
          for i:=0 to high(RelocationTable[j]) do
            with RelocationTable[j,i] do
              begin
                case j of
                  0:
                    begin
                      SegI:=FindCodeSegment(RelocOffset);
                      if SegI=-1 then
                        begin
                          InputError('Relocation offset not found in code segment');
                          Exit;
                        end;
                      BaseSectionOffset:=CodeSegments[SegI].CodeSectionOffset;
                      ObjSec:=TObjSection(ObjData.ObjSectionList[FirstCodeSegmentIdx+SegI]);
                    end;
                  1:
                    begin
                      SegI:=FindDataSegment(RelocOffset);
                      if SegI=-1 then
                        begin
                          InputError('Relocation offset not found in data segment');
                          Exit;
                        end;
                      BaseSectionOffset:=DataSegments[SegI].DataSectionOffset;
                      ObjSec:=TObjSection(ObjData.ObjSectionList[FirstDataSegmentIdx+SegI]);
                    end;
                  2..2+(Ord(High(TWasmCustomDebugSectionType))-Ord(Low(TWasmCustomDebugSectionType))):
                    begin
                      BaseSectionOffset:=0;
                      ObjSec:=ObjData.findsection(WasmCustomSectionName[TWasmCustomSectionType((j-2)+Ord(Low(TWasmCustomDebugSectionType)))]);
                    end;
                  else
                    internalerror(2023122801);
                end;
                case RelocType of
                  R_WASM_FUNCTION_INDEX_LEB:
                    ObjSec.ObjRelocations.Add(TWasmObjRelocation.CreateSymbol(RelocOffset-BaseSectionOffset,SymbolTable[RelocIndex].ObjSym,RELOC_FUNCTION_INDEX_LEB));
                  R_WASM_TABLE_INDEX_SLEB:
                    ObjSec.ObjRelocations.Add(TWasmObjRelocation.CreateSymbol(RelocOffset-BaseSectionOffset,SymbolTable[RelocIndex].ObjSym,RELOC_MEMORY_ADDR_OR_TABLE_INDEX_SLEB));
                  R_WASM_TABLE_INDEX_I32:
                    ObjSec.ObjRelocations.Add(TWasmObjRelocation.CreateSymbol(RelocOffset-BaseSectionOffset,SymbolTable[RelocIndex].ObjSym,RELOC_ABSOLUTE));
                  R_WASM_MEMORY_ADDR_LEB:
                    begin
                      ObjReloc:=TWasmObjRelocation.CreateSymbol(RelocOffset-BaseSectionOffset,SymbolTable[RelocIndex].ObjSym,RELOC_MEMORY_ADDR_LEB);
                      ObjReloc.Addend:=RelocAddend;
                      ObjSec.ObjRelocations.Add(ObjReloc);
                    end;
                  R_WASM_MEMORY_ADDR_SLEB:
                    begin
                      ObjReloc:=TWasmObjRelocation.CreateSymbol(RelocOffset-BaseSectionOffset,SymbolTable[RelocIndex].ObjSym,RELOC_MEMORY_ADDR_OR_TABLE_INDEX_SLEB);
                      ObjReloc.Addend:=RelocAddend;
                      ObjSec.ObjRelocations.Add(ObjReloc);
                    end;
                  R_WASM_MEMORY_ADDR_I32:
                    begin
                      ObjReloc:=TWasmObjRelocation.CreateSymbol(RelocOffset-BaseSectionOffset,SymbolTable[RelocIndex].ObjSym,RELOC_ABSOLUTE);
                      ObjReloc.Addend:=RelocAddend;
                      ObjSec.ObjRelocations.Add(ObjReloc);
                    end;
                  R_WASM_TYPE_INDEX_LEB:
                    ObjSec.ObjRelocations.Add(TWasmObjRelocation.CreateFuncType(RelocOffset-BaseSectionOffset,FFuncTypes[RelocIndex]));
                  R_WASM_FUNCTION_OFFSET_I32:
                    begin
                      ObjReloc:=TWasmObjRelocation.CreateSymbol(RelocOffset-BaseSectionOffset,SymbolTable[RelocIndex].ObjSym,RELOC_ABSOLUTE);
                      ObjReloc.Addend:=RelocAddend;
                      ObjReloc.IsFunctionOffsetI32:=True;
                      ObjSec.ObjRelocations.Add(ObjReloc);
                    end;
                  R_WASM_SECTION_OFFSET_I32:
                    begin
                      ObjReloc:=TWasmObjRelocation.CreateSection(RelocOffset-BaseSectionOffset,SymbolTable[RelocIndex].ObjSec,RELOC_ABSOLUTE);
                      ObjReloc.Addend:=RelocAddend;
                      ObjSec.ObjRelocations.Add(ObjReloc);
                    end;
                  R_WASM_GLOBAL_INDEX_LEB:
                    begin
                      ObjSec.ObjRelocations.Add(TWasmObjRelocation.CreateSymbol(RelocOffset-BaseSectionOffset,SymbolTable[RelocIndex].ObjSym,RELOC_GLOBAL_INDEX_LEB));
                      if Assigned(SymbolTable[RelocIndex].ObjSym.TlsGlobalSym) then
                        ObjSec.ObjRelocations.Add(TWasmObjRelocation.CreateSymbol(RelocOffset-BaseSectionOffset,SymbolTable[RelocIndex].ObjSym.TlsGlobalSym,RELOC_GLOBAL_INDEX_LEB));
                    end;
                  R_WASM_GLOBAL_INDEX_I32:
                    begin
                      ObjSec.ObjRelocations.Add(TWasmObjRelocation.CreateSymbol(RelocOffset-BaseSectionOffset,SymbolTable[RelocIndex].ObjSym,RELOC_ABSOLUTE));
                      if Assigned(SymbolTable[RelocIndex].ObjSym.TlsGlobalSym) then
                        ObjSec.ObjRelocations.Add(TWasmObjRelocation.CreateSymbol(RelocOffset-BaseSectionOffset,SymbolTable[RelocIndex].ObjSym.TlsGlobalSym,RELOC_ABSOLUTE));
                    end;
                  R_WASM_TAG_INDEX_LEB:
                    ObjSec.ObjRelocations.Add(TWasmObjRelocation.CreateSymbol(RelocOffset-BaseSectionOffset,SymbolTable[RelocIndex].ObjSym,RELOC_TAG_INDEX_LEB));
                  else
                    internalerror(2023122802);
                end;
              end;

        Result:=True;
      end;

{****************************************************************************
                               TWasmExeOutput
****************************************************************************}

    procedure TWasmExeOutput.AddToNameMap(var nm: TCustomSectionNameMap; aidx: UInt32; const aname: string);
      begin
        SetLength(nm,Length(nm)+1);
        with nm[High(nm)] do
          begin
            idx:=aidx;
            name:=aname;
          end;
      end;

    procedure TWasmExeOutput.AddToFunctionNameMap(aidx: UInt32; const aname: string);
      begin
        AddToNameMap(FFunctionNameMap,aidx,aname);
      end;

    procedure TWasmExeOutput.AddToGlobalNameMap(aidx: UInt32; const aname: string);
      begin
        AddToNameMap(FGlobalNameMap,aidx,aname);
      end;

    procedure TWasmExeOutput.AddToDataNameMap(aidx: UInt32; const aname: string);
      begin
        AddToNameMap(FDataNameMap,aidx,aname);
      end;

    procedure TWasmExeOutput.AddToTagNameMap(aidx: UInt32; const aname: string);
      begin
        AddToNameMap(FTagNameMap,aidx,aname);
      end;

    procedure TWasmExeOutput.WriteWasmSection(wsid: TWasmSectionID);
      var
        b: byte;
      begin
        b:=ord(wsid);
        Writer.write(b,1);
        WriteUleb(Writer,FWasmSections[wsid].size);
        Writer.writearray(FWasmSections[wsid]);
      end;

    procedure TWasmExeOutput.WriteWasmSectionIfNotEmpty(wsid: TWasmSectionID);
      begin
        if FWasmSections[wsid].size>0 then
          WriteWasmSection(wsid);
      end;

    procedure TWasmExeOutput.WriteWasmCustomSection(wcst: TWasmCustomSectionType);
      var
        b: byte;
      begin
        b:=0;
        Writer.write(b,1);
        WriteUleb(Writer,FWasmCustomSections[wcst].size);
        Writer.writearray(FWasmCustomSections[wcst]);
      end;

    function TWasmExeOutput.writeData: boolean;

      procedure WriteImportSection;
        var
          imports_count,
          memory_imports: SizeInt;
          i: Integer;
        begin
          if assigned(exemap) then
            exemap.AddHeader('Import section');
          if ts_wasm_threads in current_settings.targetswitches then
            memory_imports:=1
          else
            memory_imports:=0;
          imports_count:=Length(FFunctionImports)+memory_imports;
          WriteUleb(FWasmSections[wsiImport],imports_count);
          if ts_wasm_threads in current_settings.targetswitches then
            begin
              WriteName(FWasmSections[wsiImport],'env');
              WriteName(FWasmSections[wsiImport],'memory');
              WriteByte(FWasmSections[wsiImport],$02);  { mem }
              WriteByte(FWasmSections[wsiImport],$03);  { shared }
              WriteUleb(FWasmSections[wsiImport],FMinMemoryPages);
              WriteUleb(FWasmSections[wsiImport],Max(FMinMemoryPages,FMaxMemoryPages));  { max pages }
              if assigned(exemap) then
                exemap.Add('  Memory[0] pages: initial='+tostr(FMinMemoryPages)+' max='+tostr(Max(FMinMemoryPages,FMaxMemoryPages))+' shared <- env.memory');
            end;
          for i:=0 to Length(FFunctionImports)-1 do
            with FFunctionImports[i] do
              begin
                WriteName(FWasmSections[wsiImport],ModName);
                WriteName(FWasmSections[wsiImport],Name);
                WriteByte(FWasmSections[wsiImport],$00);  { func }
                WriteUleb(FWasmSections[wsiImport],TypeIdx);
                if assigned(exemap) then
                  exemap.Add('  Function['+tostr(i)+'] sig='+tostr(TypeIdx)+' <- '+ModName+'.'+Name);
              end;
        end;

      procedure WriteCodeSegments;
        var
          i: Integer;
          exesec: TExeSection;
          objsec: TWasmObjSection;
        begin
          exesec:=FindExeSection('.text');
          if not assigned(exesec) then
            internalerror(2023123102);
          if not (oso_Data in exesec.SecOptions) then
            internalerror(2023123103);
          WriteUleb(FWasmSections[wsiFunction],exesec.ObjSectionList.Count);
          WriteUleb(FWasmSections[wsiCode],exesec.ObjSectionList.Count);
          for i:=0 to exesec.ObjSectionList.Count-1 do
            begin
              objsec:=TWasmObjSection(exesec.ObjSectionList[i]);
              if not (oso_data in objsec.secoptions) then
                internalerror(2023123104);
              if not assigned(objsec.data) then
                internalerror(2023123105);
              if objsec.MainFuncSymbol.LinkingData.ExeFunctionIndex<>(i+Length(FFunctionImports)) then
                internalerror(2024010101);
              WriteUleb(FWasmSections[wsiFunction],objsec.MainFuncSymbol.LinkingData.ExeTypeIndex);
              WriteUleb(FWasmSections[wsiCode],objsec.Data.size);
              objsec.Data.seek(0);
              CopyDynamicArray(objsec.Data,FWasmSections[wsiCode],objsec.Data.size);
            end;
        end;

      procedure WriteDataSegments;

        procedure WriteExeSection(exesec: TExeSection);
          var
            i: Integer;
            objsec: TObjSection;
            exesecdatapos: LongWord;
            dpos, pad: QWord;
          begin
            AddToDataNameMap(Length(FDataNameMap),exesec.Name);
            if ts_wasm_threads in current_settings.targetswitches then
              WriteByte(FWasmSections[wsiData],1)  { mode passive }
            else
              begin
                WriteByte(FWasmSections[wsiData],0);  { mode active, memory 0, offset e }

                WriteByte(FWasmSections[wsiData],$41);  { i32.const }
                WriteSleb(FWasmSections[wsiData],longint(exesec.MemPos));
                WriteByte(FWasmSections[wsiData],$0B);  { end }
              end;

            WriteUleb(FWasmSections[wsiData],exesec.Size);
            exesecdatapos:=FWasmSections[wsiData].size;
            for i:=0 to exesec.ObjSectionList.Count-1 do
              begin
                objsec:=TObjSection(exesec.ObjSectionList[i]);
                if not (oso_data in objsec.secoptions) then
                  internalerror(2024010104);
                if not assigned(objsec.data) then
                  internalerror(2024010105);

                dpos:=objsec.MemPos-exesec.MemPos+exesecdatapos;
                pad:=dpos-FWasmSections[wsiData].size;
                { objsection must be within SecAlign bytes from the previous one }
                if (dpos<FWasmSections[wsiData].Size) or
                  (pad>=max(objsec.SecAlign,1)) then
                  internalerror(2024010106);
                writeZeros(FWasmSections[wsiData],pad);

                objsec.data.seek(0);
                CopyDynamicArray(objsec.data,FWasmSections[wsiData],objsec.data.size);
              end;
            if (FWasmSections[wsiData].size-exesecdatapos)<>exesec.Size then
              internalerror(2024010107);
          end;

        var
          DataCount: Integer;
          DataSecName: string;
          ExeSec: TExeSection;
        begin
          DataCount:=0;
          for DataSecName in DataSections do
            begin
              ExeSec:=FindExeSection(DataSecName);
              if Assigned(ExeSec) and (ExeSec.Size>0) then
                Inc(DataCount);
            end;
          WriteUleb(FWasmSections[wsiDataCount],DataCount);
          WriteUleb(FWasmSections[wsiData],DataCount);
          for DataSecName in DataSections do
            begin
              ExeSec:=FindExeSection(DataSecName);
              if Assigned(ExeSec) and (ExeSec.Size>0) then
                WriteExeSection(ExeSec);
            end;
        end;

      procedure WriteTableAndElemSections;
        const
          TableCount=1;
        var
          i: Integer;
        begin
          { Table section }

          WriteUleb(FWasmSections[wsiTable],TableCount);
          { table 0 }
          {   table type }
          WriteByte(FWasmSections[wsiTable],encode_wasm_basic_type(wbt_funcref));
          {   table limits }
          WriteByte(FWasmSections[wsiTable],$01);  { has min & max }
          WriteUleb(FWasmSections[wsiTable],Length(FIndirectFunctionTable));  { min }
          WriteUleb(FWasmSections[wsiTable],Length(FIndirectFunctionTable));  { max }

          { Elem section }

          WriteUleb(FWasmSections[wsiElement],1);  { 1 element segment }
          { element segment 0 }
          WriteByte(FWasmSections[wsiElement],0);  { type funcref, init((ref.func y) end)*, mode active <table 0, offset e> }
          { e:expr }
          WriteByte(FWasmSections[wsiElement],$41);  { i32.const }
          WriteSleb(FWasmSections[wsiElement],1);    { starting from 1 (table entry 0 is ref.null) }
          WriteByte(FWasmSections[wsiElement],$0B);  { end }
          { y*:vec(funcidx) }
          WriteUleb(FWasmSections[wsiElement],Length(FIndirectFunctionTable)-1);
          for i:=1 to Length(FIndirectFunctionTable)-1 do
            WriteUleb(FWasmSections[wsiElement],FIndirectFunctionTable[i].FuncIdx);
        end;

      procedure WriteGlobalSection;
        var
          exesec: TExeSection;
          globals_count, i: Integer;
          objsec: TWasmObjSection;
        begin
          exesec:=FindExeSection('.wasm_globals');
          if not assigned(exesec) then
            internalerror(2024010112);
          globals_count:=exesec.ObjSectionList.Count;
          if globals_count<>exesec.Size then
            internalerror(2024010113);
          WriteUleb(FWasmSections[wsiGlobal],globals_count);
          for i:=0 to exesec.ObjSectionList.Count-1 do
            begin
              objsec:=TWasmObjSection(exesec.ObjSectionList[i]);
              WriteByte(FWasmSections[wsiGlobal],encode_wasm_basic_type(objsec.MainFuncSymbol.LinkingData.GlobalType));
              if objsec.MainFuncSymbol.LinkingData.GlobalIsMutable then
                WriteByte(FWasmSections[wsiGlobal],1)
              else
                WriteByte(FWasmSections[wsiGlobal],0);
              { initializer expr }
              with objsec.MainFuncSymbol.LinkingData.GlobalInitializer do
                case typ of
                  wbt_i32:
                    begin
                      WriteByte(FWasmSections[wsiGlobal],$41);  { i32.const }
                      WriteSleb(FWasmSections[wsiGlobal],init_i32);
                    end;
                  wbt_i64:
                    begin
                      WriteByte(FWasmSections[wsiGlobal],$42);  { i64.const }
                      WriteSleb(FWasmSections[wsiGlobal],init_i64);
                    end;
                  wbt_f32:
                    begin
                      WriteByte(FWasmSections[wsiGlobal],$43);  { f32.const }
                      WriteF32LE(FWasmSections[wsiGlobal],init_f32);
                    end;
                  wbt_f64:
                    begin
                      WriteByte(FWasmSections[wsiGlobal],$44);  { f64.const }
                      WriteF64LE(FWasmSections[wsiGlobal],init_f64);
                    end;
                  wbt_funcref,
                  wbt_externref:
                    begin
                      WriteByte(FWasmSections[wsiGlobal],$D0);  { ref.null }
                      WriteByte(FWasmSections[wsiGlobal],encode_wasm_basic_type(typ));
                    end;
                  else
                    internalerror(2024010114);
                end;
              WriteByte(FWasmSections[wsiGlobal],$0B);  { end }
              { add entry for the name section }
              AddToGlobalNameMap(i,objsec.MainFuncSymbol.Name);
            end;
        end;

      procedure WriteTagSection;
        var
          exesec: TExeSection;
          tags_count, i: Integer;
          objsec: TWasmObjSection;
        begin
          exesec:=FindExeSection('.wasm_tags');
          if not assigned(exesec) then
            exit;
          tags_count:=exesec.ObjSectionList.Count;
          if tags_count<>exesec.Size then
            internalerror(2024010702);
          if tags_count=0 then
            exit;
          WriteUleb(FWasmSections[wsiTag],tags_count);
          for i:=0 to exesec.ObjSectionList.Count-1 do
            begin
              objsec:=TWasmObjSection(exesec.ObjSectionList[i]);
              WriteByte(FWasmSections[wsiTag],0);
              WriteUleb(FWasmSections[wsiTag],objsec.MainFuncSymbol.LinkingData.ExeTypeIndex);
              AddToTagNameMap(i,objsec.MainFuncSymbol.Name);
            end;
        end;

      procedure WriteExportSection;
        const
          MemoryExportsCount=1;
        var
          FunctionExportsCount: Integer;
          ExportsCount: Integer;
          textsec: TExeSection;
          i: Integer;
          objsec: TWasmObjSection;
        begin
          if assigned(exemap) then
            exemap.AddHeader('Export section');
          FunctionExportsCount:=0;
          textsec:=FindExeSection('.text');
          if not assigned(textsec) then
            internalerror(2024010115);
          for i:=0 to textsec.ObjSectionList.Count-1 do
            begin
              objsec:=TWasmObjSection(textsec.ObjSectionList[i]);
              if objsec.MainFuncSymbol.LinkingData.IsExported then
                Inc(FunctionExportsCount)
            end;

          ExportsCount:=MemoryExportsCount+FunctionExportsCount;

          WriteUleb(FWasmSections[wsiExport],ExportsCount);
          { export 0 }
          WriteName(FWasmSections[wsiExport],'memory');
          WriteByte(FWasmSections[wsiExport],$02);  { mem }
          WriteUleb(FWasmSections[wsiExport],0);    { memidx = 0 }
          if assigned(exemap) then
            exemap.Add('  Memory[0] -> "memory"');

          for i:=0 to textsec.ObjSectionList.Count-1 do
            begin
              objsec:=TWasmObjSection(textsec.ObjSectionList[i]);
              if objsec.MainFuncSymbol.LinkingData.IsExported then
                begin
                  WriteName(FWasmSections[wsiExport],objsec.MainFuncSymbol.LinkingData.ExportName);
                  WriteByte(FWasmSections[wsiExport],$00);  { func }
                  WriteUleb(FWasmSections[wsiExport],objsec.MainFuncSymbol.LinkingData.ExeFunctionIndex);    { funcidx }
                  if assigned(exemap) then
                    exemap.Add('  Function['+tostr(objsec.MainFuncSymbol.LinkingData.ExeFunctionIndex)+'] -> "'+objsec.MainFuncSymbol.LinkingData.ExportName+'"');
                end;
            end;
        end;

      procedure MaybeWriteDebugSection(st: TWasmCustomDebugSectionType);
        var
          exesec: TExeSection;
        begin
          exesec:=FindExeSection(WasmCustomSectionName[st]);
          if assigned(exesec) then
            begin
              WriteExeSectionToDynArray(exesec,FWasmCustomSections[st]);
              WriteWasmCustomSection(st);
            end;
        end;

      procedure WriteNameMap(const nm: TCustomSectionNameMap; dest: tdynamicarray);
        var
          i: Integer;
        begin
          WriteUleb(dest,Length(nm));
          for i:=low(nm) to high(nm) do
            with nm[i] do
              begin
                WriteUleb(dest,idx);
                WriteName(dest,name);
              end;
        end;

      procedure WriteNameSubsection(wnst: TWasmNameSubsectionType);
        begin
          if FWasmNameSubsections[wnst].size>0 then
            begin
              WriteByte(FWasmCustomSections[wcstName],Ord(wnst));
              WriteUleb(FWasmCustomSections[wcstName],FWasmNameSubsections[wnst].size);
              FWasmNameSubsections[wnst].seek(0);
              CopyDynamicArray(FWasmNameSubsections[wnst],FWasmCustomSections[wcstName],FWasmNameSubsections[wnst].size);
            end;
        end;

      procedure WriteNameSection;
        begin
          WriteName(FWasmNameSubsections[wnstModuleName],current_module.exefilename);
          WriteNameSubsection(wnstModuleName);

          WriteNameMap(FFunctionNameMap,FWasmNameSubsections[wnstFunctionNames]);
          WriteNameSubsection(wnstFunctionNames);

          WriteNameMap(FGlobalNameMap,FWasmNameSubsections[wnstGlobalNames]);
          WriteNameSubsection(wnstGlobalNames);

          WriteNameMap(FDataNameMap,FWasmNameSubsections[wnstDataNames]);
          WriteNameSubsection(wnstDataNames);

          if Length(FTagNameMap)>0 then
            begin
              WriteNameMap(FTagNameMap,FWasmNameSubsections[wnstTagNames]);
              WriteNameSubsection(wnstTagNames);
            end;
        end;

      var
        cust_sec: TWasmCustomSectionType;
      begin
        result:=false;
        FMaxMemoryPages:=align(maxheapsize,WasmPageSize) div WasmPageSize;

        { each custom sections starts with its name }
        for cust_sec in TWasmCustomSectionType do
          WriteName(FWasmCustomSections[cust_sec],WasmCustomSectionName[cust_sec]);

        SetStackPointer;
        SetTlsSizeAlignAndBase;
        SetThreadVarGlobalsInitValues;
        GenerateCode_InitTls;
        GenerateCode_InitSharedMemory;

        FFuncTypes.WriteTo(FWasmSections[wsiType]);
        WriteImportSection;
        WriteCodeSegments;
        WriteDataSegments;
        WriteTableAndElemSections;
        WriteGlobalSection;
        WriteTagSection;

        if not (ts_wasm_threads in current_settings.targetswitches) then
          begin
            if assigned(exemap) then
              exemap.AddHeader('Memory section');
            WriteUleb(FWasmSections[wsiMemory],1);
            if FMaxMemoryPages>=FMinMemoryPages then
              begin
                WriteByte(FWasmSections[wsiMemory],1);
                WriteUleb(FWasmSections[wsiMemory],FMinMemoryPages);
                WriteUleb(FWasmSections[wsiMemory],FMaxMemoryPages);
                if assigned(exemap) then
                  exemap.Add('  Memory[0] pages: initial='+tostr(FMinMemoryPages)+' max='+tostr(FMaxMemoryPages));
              end
            else
              begin
                WriteByte(FWasmSections[wsiMemory],0);
                WriteUleb(FWasmSections[wsiMemory],FMinMemoryPages);
                if assigned(exemap) then
                  exemap.Add('  Memory[0] pages: initial='+tostr(FMinMemoryPages));
              end;
          end;

        WriteExportSection;

        if ts_wasm_threads in current_settings.targetswitches then
          WriteUleb(FWasmSections[wsiStart],FInitSharedMemoryFunctionSym.LinkingData.ExeFunctionIndex);

        WriteNameSection;

        Writer.write(WasmModuleMagic,SizeOf(WasmModuleMagic));
        Writer.write(WasmVersion,SizeOf(WasmVersion));
        WriteWasmSection(wsiType);
        WriteWasmSection(wsiImport);
        WriteWasmSection(wsiFunction);
        WriteWasmSection(wsiTable);
        if not (ts_wasm_threads in current_settings.targetswitches) then
          WriteWasmSection(wsiMemory);
        WriteWasmSectionIfNotEmpty(wsiTag);
        WriteWasmSection(wsiGlobal);
        WriteWasmSection(wsiExport);
        if ts_wasm_threads in current_settings.targetswitches then
          WriteWasmSection(wsiStart);
        WriteWasmSection(wsiElement);
        WriteWasmSection(wsiDataCount);
        WriteWasmSection(wsiCode);
        WriteWasmSection(wsiData);

        MaybeWriteDebugSection(wcstDebugAbbrev);
        MaybeWriteDebugSection(wcstDebugInfo);
        MaybeWriteDebugSection(wcstDebugStr);
        MaybeWriteDebugSection(wcstDebugLine);
        MaybeWriteDebugSection(wcstDebugFrame);
        MaybeWriteDebugSection(wcstDebugAranges);
        MaybeWriteDebugSection(wcstDebugRanges);

        WriteWasmCustomSection(wcstName);

        result := true;
      end;

    procedure TWasmExeOutput.DoRelocationFixup(objsec: TObjSection);

      procedure writeUInt32LE(v: uint32);
        begin
{$ifdef FPC_BIG_ENDIAN}
          v:=SwapEndian(v);
{$endif FPC_BIG_ENDIAN}
          objsec.data.write(v,4);
        end;

      var
        i: Integer;
        objreloc: TWasmObjRelocation;
        objsym: TWasmObjSymbol;
      begin
        for i:=0 to objsec.ObjRelocations.Count-1 do
          begin
            objreloc:=TWasmObjRelocation(objsec.ObjRelocations[i]);
            if assigned(objreloc.symbol) then
              begin
                objsym:=TWasmObjSymbol(objreloc.symbol);
                case objreloc.typ of
                  RELOC_FUNCTION_INDEX_LEB:
                    begin
                      if objsym.LinkingData.ExeFunctionIndex=-1 then
                        internalerror(2024010103);
                      if FRelocationPass=2 then
                        begin
                          objsec.Data.seek(objreloc.DataOffset);
                          WriteUleb5(objsec.Data,objsym.LinkingData.ExeFunctionIndex);
                        end;
                    end;
                  RELOC_ABSOLUTE:
                    begin
                      case objsym.typ of
                        AT_FUNCTION:
                          begin
                            if objreloc.IsFunctionOffsetI32 then
                              begin
                                { R_WASM_FUNCTION_OFFSET_I32 }
                                if FRelocationPass=2 then
                                  begin
                                    objsec.Data.seek(objreloc.DataOffset);
                                    writeUInt32LE(UInt32(objsym.objsection.MemPos+objreloc.Addend));
                                  end;
                              end
                            else
                              begin
                                { R_WASM_TABLE_INDEX_I32 }
                                if objsym.LinkingData.ExeFunctionIndex=-1 then
                                  internalerror(2024010103);
                                case FRelocationPass of
                                  1:
                                    if objsym.LinkingData.ExeIndirectFunctionTableIndex=-1 then
                                      objsym.LinkingData.ExeIndirectFunctionTableIndex:=AddOrGetIndirectFunctionTableIndex(objsym.LinkingData.ExeFunctionIndex);
                                  2:
                                    begin
                                      objsec.Data.seek(objreloc.DataOffset);
                                      writeUInt32LE(UInt32(objsym.LinkingData.ExeIndirectFunctionTableIndex));
                                    end;
                                end;
                              end;
                          end;
                        AT_DATA:
                          begin
                            if objreloc.IsFunctionOffsetI32 then
                              internalerror(2024010602);
                            if FRelocationPass=2 then
                              begin
                                objsec.Data.seek(objreloc.DataOffset);
                                writeUInt32LE(UInt32((objsym.offset+objsym.objsection.MemPos)+objreloc.Addend));
                              end;
                          end;
                        AT_TLS:
                          begin
                            if objreloc.IsFunctionOffsetI32 then
                              internalerror(2024010602);
                            if FRelocationPass=2 then
                              begin
                                objsec.Data.seek(objreloc.DataOffset);
                                writeUInt32LE(UInt32((objsym.offset+objsym.objsection.MemPos-objsym.objsection.ExeSection.MemPos)+objreloc.Addend));
                              end;
                          end;
                        AT_WASM_GLOBAL:
                          begin
                            if objreloc.IsFunctionOffsetI32 then
                              internalerror(2024010602);
                            if FRelocationPass=2 then
                              begin
                                objsec.Data.seek(objreloc.DataOffset);
                                writeUInt32LE(UInt32(objsym.offset+objsym.objsection.MemPos));
                              end;
                          end;
                        else
                          internalerror(2024010108);
                      end;
                    end;
                  RELOC_MEMORY_ADDR_LEB:
                    begin
                      if objsym.typ<>AT_DATA then
                        internalerror(2024010109);
                      if FRelocationPass=2 then
                        begin
                          objsec.Data.seek(objreloc.DataOffset);
                          WriteUleb5(objsec.Data,UInt32((objsym.offset+objsym.objsection.MemPos)+objreloc.Addend));
                        end;
                    end;
                  RELOC_MEMORY_ADDR_OR_TABLE_INDEX_SLEB:
                    begin
                      case objsym.typ of
                        AT_FUNCTION:
                          begin
                            if objsym.LinkingData.ExeFunctionIndex=-1 then
                              internalerror(2024010103);
                            case FRelocationPass of
                              1:
                                if objsym.LinkingData.ExeIndirectFunctionTableIndex=-1 then
                                  objsym.LinkingData.ExeIndirectFunctionTableIndex:=AddOrGetIndirectFunctionTableIndex(objsym.LinkingData.ExeFunctionIndex);
                              2:
                                begin
                                  objsec.Data.seek(objreloc.DataOffset);
                                  WriteSleb5(objsec.Data,Int32(objsym.LinkingData.ExeIndirectFunctionTableIndex));
                                end;
                            end;
                          end;
                        AT_DATA:
                          begin
                            if FRelocationPass=2 then
                              begin
                                objsec.Data.seek(objreloc.DataOffset);
                                WriteSleb5(objsec.Data,Int32((objsym.offset+objsym.objsection.MemPos)+objreloc.Addend));
                              end;
                          end;
                        else
                          internalerror(2024010110);
                      end;
                    end;
                  RELOC_GLOBAL_INDEX_LEB:
                    if objsym.typ=AT_WASM_GLOBAL then
                      begin
                        if FRelocationPass=2 then
                          begin
                            objsec.Data.seek(objreloc.DataOffset);
                            WriteUleb5(objsec.Data,UInt32(objsym.offset+objsym.objsection.MemPos));
                          end;
                      end
                    else if (ts_wasm_threads in current_settings.targetswitches) and
                            (objsym.typ=AT_TLS) then
                      begin
                        { Nothing to do here. A second RELOC_GLOBAL_INDEX_LEB
                          relocation, overlaid on top of this one, pointing to
                          an AT_WASM_GLOBAL should have already done the job. }
                      end
                    else
                      internalerror(2024010111);
                  RELOC_TAG_INDEX_LEB:
                    begin
                      if objsym.typ<>AT_WASM_EXCEPTION_TAG then
                        internalerror(2024010708);
                      if FRelocationPass=2 then
                        begin
                          objsec.Data.seek(objreloc.DataOffset);
                          WriteUleb5(objsec.Data,UInt32(objsym.offset+objsym.objsection.MemPos));
                        end;
                    end;
                  else
                    internalerror(2024010109);
                end;
              end
            else if assigned(objreloc.objsection) then
              begin
                if objreloc.typ<>RELOC_ABSOLUTE then
                  internalerror(2024010601);
                if FRelocationPass=2 then
                  begin
                    objsec.Data.seek(objreloc.DataOffset);
                    writeUInt32LE(UInt32((objreloc.objsection.MemPos)+objreloc.Addend));
                  end;
              end
            else if objreloc.typ=RELOC_TYPE_INDEX_LEB then
              begin
                case FRelocationPass of
                  1:
                    objreloc.ExeTypeIndex:=FFuncTypes.AddOrGetFuncType(objreloc.FuncType);
                  2:
                    begin
                      objsec.Data.seek(objreloc.DataOffset);
                      WriteUleb5(objsec.Data,objreloc.ExeTypeIndex);
                    end;
                end;
              end
            else
              internalerror(2024010110);
          end;
      end;

    constructor TWasmExeOutput.create;
      var
        i: TWasmSectionID;
        j: TWasmCustomSectionType;
        k: TWasmNameSubsectionType;
      begin
        inherited create;
        CObjData:=TWasmObjData;
        SectionMemAlign:=16;
        MaxMemPos:=$FFFFFFFF;
        FFuncTypes:=TWasmFuncTypeTable.Create;
        for i in TWasmSectionID do
          FWasmSections[i] := tdynamicarray.create(SectionDataMaxGrow);
        for j in TWasmCustomSectionType do
          FWasmCustomSections[j] := tdynamicarray.create(SectionDataMaxGrow);
        for k:=low(FWasmNameSubsections) to high(FWasmNameSubsections) do
          FWasmNameSubsections[k] := tdynamicarray.create(SectionDataMaxGrow);
        SetLength(FIndirectFunctionTable,1);
        FIndirectFunctionTable[0].FuncIdx:=-1;
      end;

    destructor TWasmExeOutput.destroy;
      var
        i: TWasmSectionID;
        j: TWasmCustomSectionType;
        k: TWasmNameSubsectionType;
      begin
        for i in TWasmSectionID do
          FWasmSections[i].Free;
        for j in TWasmCustomSectionType do
          FWasmCustomSections[j].Free;
        for k:=low(FWasmNameSubsections) to high(FWasmNameSubsections) do
          FWasmNameSubsections[k].Free;
        FFuncTypes.Free;
        inherited destroy;
      end;

    procedure TWasmExeOutput.GenerateLibraryImports(ImportLibraryList: TFPHashObjectList);
      var
        i, j: Integer;
        ImportLibrary: TImportLibrary;
        ImportSymbol: TImportSymbol;
        exesym: TExeSymbol;
      begin
        { Here map import symbols to exe symbols and create necessary sections.
          Actual import generation is done after unused sections (and symbols) are removed. }
        FImports:=ImportLibraryList;
        for i:=0 to ImportLibraryList.Count-1 do
          begin
            ImportLibrary:=TImportLibrary(ImportLibraryList[i]);
            for j:=0 to ImportLibrary.ImportSymbolList.Count-1 do
              begin
                ImportSymbol:=TImportSymbol(ImportLibrary.ImportSymbolList[j]);
                exesym:=TExeSymbol(ExeSymbolList.Find(ImportSymbol.MangledName));
                if assigned(exesym) and
                   (exesym.State<>symstate_defined) then
                  begin
                    ImportSymbol.CachedExeSymbol:=exesym;
                    exesym.State:=symstate_defined;
                  end;
              end;
          end;
        PackUnresolvedExeSymbols('after module imports');
      end;

    procedure TWasmExeOutput.AfterUnusedSectionRemoval;
      begin
        PrepareImports;
        PrepareFunctions;
        PrepareTags;

        if Assigned(exemap) then
          WriteMap_TypeSection;

        { we do an extra preliminary relocation pass, in order to prepare the
          indices for the Type section and the Table section. This is required
          by GenerateCode_InvokeHelper. }
        FRelocationPass:=1;
        FixupRelocations;

        { in pass 2, we do the actual relocation fixups. No need to call
          FixupRelocations here, since it'll be called in
          TInternalLinker.RunLinkScript, after this method finishes. We only
          set the FRelocationPass variable here, so DoRelocationFixup knows
          which pass it is. }
        FRelocationPass:=2;

        { This needs to be done before pass 2 of the relocation fixups, because
          it'll generate code, thus it'll move the offsets of the functions that
          follow it in the Code section, and we want our DWARF debug info to
          contain correct code offsets. }
        GenerateCode_InvokeHelper;

        if Assigned(exemap) then
          WriteMap_IndirectFunctionTable;
      end;

    procedure TWasmExeOutput.MemPos_ExeSection(const aname: string);
      const
        DebugPrefix = '.debug_';
      var
        ExeSec: TExeSection;
        i: Integer;
        objsec: TObjSection;
        firstdatasec: string;
      begin
        { WebAssembly is a Harvard architecture.
          Data lives in a separate address space, so start addressing back from 0
          (the LLVM leaves the first 1024 bytes in the data segment empty, so we
          start at 1024). }
        if ts_wasm_threads in current_settings.targetswitches then
          firstdatasec:='.tbss'
        else
          firstdatasec:='.rodata';
        if aname=firstdatasec then
          begin
            CurrMemPos:=1024;
            inherited;
          end
        else if aname='.text' then
          begin
            CurrMemPos:=0;
            ExeSec:=FindExeSection(aname);
            if not assigned(ExeSec) then
              exit;
            exesec.MemPos:=CurrMemPos;

            CurrMemPos:=CurrMemPos+UlebEncodingSize(exesec.ObjSectionList.Count);

            { set position of object ObjSections }
            for i:=0 to exesec.ObjSectionList.Count-1 do
              begin
                objsec:=TObjSection(exesec.ObjSectionList[i]);
                CurrMemPos:=CurrMemPos+UlebEncodingSize(objsec.Size);
                CurrMemPos:=objsec.setmempos(CurrMemPos);
              end;

            { calculate size of the section }
            exesec.Size:=CurrMemPos-exesec.MemPos;
          end
        else if (aname='.wasm_globals') or (aname='.wasm_tags') or
                (Copy(aname,1,Length(DebugPrefix))=DebugPrefix) then
          begin
            CurrMemPos:=0;
            inherited;
          end
        else
          inherited;
      end;

    procedure TWasmExeOutput.Load_Symbol(const aname: string);
      begin
        if aname=StackPointerSymStr then
          begin
            internalObjData.createsection('*'+aname,1,[oso_Data,oso_load]);
            FStackPointerSym:=TWasmObjSymbol(internalObjData.SymbolDefine(aname,AB_GLOBAL,AT_WASM_GLOBAL));
            FStackPointerSym.size:=1;
            FStackPointerSym.ObjSection.WriteZeros(1);
            TWasmObjSection(FStackPointerSym.ObjSection).MainFuncSymbol:=FStackPointerSym;
            FStackPointerSym.LinkingData.GlobalType:=wbt_i32;
            FStackPointerSym.LinkingData.GlobalIsMutable:=True;
            FStackPointerSym.LinkingData.GlobalInitializer.typ:=wbt_i32;
            FStackPointerSym.LinkingData.GlobalInitializer.init_i32:=0;
          end
        else if (ts_wasm_threads in current_settings.targetswitches) and (aname='__tls_base') then
          begin
            internalObjData.createsection('*'+aname,1,[oso_Data,oso_load]);
            FTlsBaseSym:=TWasmObjSymbol(internalObjData.SymbolDefine(aname,AB_GLOBAL,AT_WASM_GLOBAL));
            FTlsBaseSym.size:=1;
            FTlsBaseSym.ObjSection.WriteZeros(1);
            TWasmObjSection(FTlsBaseSym.ObjSection).MainFuncSymbol:=FTlsBaseSym;
            FTlsBaseSym.LinkingData.GlobalType:=wbt_i32;
            FTlsBaseSym.LinkingData.GlobalIsMutable:=True;
            FTlsBaseSym.LinkingData.GlobalInitializer.typ:=wbt_i32;
            FTlsBaseSym.LinkingData.GlobalInitializer.init_i32:=0;
          end
        else if (ts_wasm_threads in current_settings.targetswitches) and (aname='__tls_size') then
          begin
            internalObjData.createsection('*'+aname,1,[oso_Data,oso_load]);
            FTlsSizeSym:=TWasmObjSymbol(internalObjData.SymbolDefine(aname,AB_GLOBAL,AT_WASM_GLOBAL));
            FTlsSizeSym.size:=1;
            FTlsSizeSym.ObjSection.WriteZeros(1);
            TWasmObjSection(FTlsSizeSym.ObjSection).MainFuncSymbol:=FTlsSizeSym;
            FTlsSizeSym.LinkingData.GlobalType:=wbt_i32;
            FTlsSizeSym.LinkingData.GlobalIsMutable:=False;
            FTlsSizeSym.LinkingData.GlobalInitializer.typ:=wbt_i32;
            FTlsSizeSym.LinkingData.GlobalInitializer.init_i32:=0;
          end
        else if (ts_wasm_threads in current_settings.targetswitches) and (aname='__tls_align') then
          begin
            internalObjData.createsection('*'+aname,1,[oso_Data,oso_load]);
            FTlsAlignSym:=TWasmObjSymbol(internalObjData.SymbolDefine(aname,AB_GLOBAL,AT_WASM_GLOBAL));
            FTlsAlignSym.size:=1;
            FTlsAlignSym.ObjSection.WriteZeros(1);
            TWasmObjSection(FTlsAlignSym.ObjSection).MainFuncSymbol:=FTlsAlignSym;
            FTlsAlignSym.LinkingData.GlobalType:=wbt_i32;
            FTlsAlignSym.LinkingData.GlobalIsMutable:=False;
            FTlsAlignSym.LinkingData.GlobalInitializer.typ:=wbt_i32;
            FTlsAlignSym.LinkingData.GlobalInitializer.init_i32:=0;
          end
        else if (ts_wasm_threads in current_settings.targetswitches) and (aname='__wasm_init_tls') then
          begin
            internalObjData.createsection('*'+aname,0,[]);
            FInitTlsFunctionSym:=TWasmObjSymbol(internalObjData.SymbolDefine(aname,AB_GLOBAL,AT_FUNCTION));
            TWasmObjSection(FInitTlsFunctionSym.ObjSection).MainFuncSymbol:=FInitTlsFunctionSym;
            FInitTlsFunctionSym.LinkingData.FuncType:=TWasmFuncType.Create([wbt_i32],[]);
          end
        else if (ts_wasm_threads in current_settings.targetswitches) and (aname='__fpc_wasm_init_shared_memory') then
          begin
            internalObjData.createsection('*'+aname,0,[]);
            FInitSharedMemoryFunctionSym:=TWasmObjSymbol(internalObjData.SymbolDefine(aname,AB_GLOBAL,AT_FUNCTION));
            TWasmObjSection(FInitSharedMemoryFunctionSym.ObjSection).MainFuncSymbol:=FInitSharedMemoryFunctionSym;
            FInitSharedMemoryFunctionSym.ObjSection.SecOptions:=FInitSharedMemoryFunctionSym.ObjSection.SecOptions+[oso_keep];
            FInitSharedMemoryFunctionSym.LinkingData.FuncType:=TWasmFuncType.Create([],[]);
          end
        else
          inherited;
      end;

    procedure TWasmExeOutput.PrepareImports;

      function AddFunctionImport(const libname,symname:TCmdStr; functype: TWasmFuncType): Integer;
        begin
          SetLength(FFunctionImports,Length(FFunctionImports)+1);
          Result:=High(FFunctionImports);
          if assigned(exemap) then
            exemap.Add('  Importing Function[' + tostr(Result) + '] ' + symname + functype.ToString);
          with FFunctionImports[Result] do
            begin
              ModName:=libname;
              Name:=symname;
              TypeIdx:=FFuncTypes.AddOrGetFuncType(functype);
            end;
        end;

      var
        i, j: Integer;
        ImportLibrary: TImportLibrary;
        ImportSymbol: TImportSymbol;
        exesym: TExeSymbol;
        newdll: Boolean;
        fsym: TWasmObjSymbol;
        objdata: TObjData;
      begin
        for i:=0 to FImports.Count-1 do
          begin
            ImportLibrary:=TImportLibrary(FImports[i]);
            newdll:=False;
            for j:=0 to ImportLibrary.ImportSymbolList.Count-1 do
              begin
                ImportSymbol:=TImportSymbol(ImportLibrary.ImportSymbolList[j]);
                exesym:=ImportSymbol.CachedExeSymbol;
                if assigned(exesym) and
                   exesym.Used then
                  begin
                    if (not newdll) and assigned(exemap) then
                      begin
                        exemap.Add('');
                        exemap.Add('Importing from module '+ImportLibrary.Name);
                      end;
                    newdll:=True;
                    TWasmObjSymbol(exesym.ObjSymbol).LinkingData.ExeFunctionIndex:=
                      AddFunctionImport(ImportLibrary.Name,ImportSymbol.Name,TWasmObjSymbol(exesym.ObjSymbol).LinkingData.FuncType);
                    AddToFunctionNameMap(TWasmObjSymbol(exesym.ObjSymbol).LinkingData.ExeFunctionIndex,ImportSymbol.MangledName);
                  end;
              end;
          end;

        { set ExeFunctionIndex to the alias symbols as well }
        for i:=0 to ObjDataList.Count-1 do
          begin
            objdata:=TObjData(ObjDataList[i]);
            for j:=0 to objdata.ObjSymbolList.Count-1 do
              begin
                fsym:=TWasmObjSymbol(objdata.ObjSymbolList[j]);
                if (fsym.LinkingData.ExeFunctionIndex=-1) and assigned(fsym.exesymbol) and (TWasmObjSymbol(fsym.exesymbol.ObjSymbol).LinkingData.ExeFunctionIndex<>-1) then
                  fsym.LinkingData.ExeFunctionIndex:=TWasmObjSymbol(fsym.exesymbol.ObjSymbol).LinkingData.ExeFunctionIndex;
              end;
          end;
      end;

    procedure TWasmExeOutput.PrepareFunctions;
      var
        i, j: Integer;
        exesec: TExeSection;
        objsec: TWasmObjSection;
        fsym: TWasmObjSymbol;
        objdata: TObjData;
      begin
        if assigned(exemap) then
          begin
            exemap.Add('');
            exemap.Add('Functions, defined in this module:');
          end;
        exesec:=FindExeSection('.text');
        if not assigned(exesec) then
          internalerror(2023123106);
        for i:=0 to exesec.ObjSectionList.Count-1 do
          begin
            objsec:=TWasmObjSection(exesec.ObjSectionList[i]);
            fsym:=objsec.MainFuncSymbol;
            if not assigned(fsym) then
              internalerror(2023123107);
            if not assigned(fsym.LinkingData.FuncType) then
              internalerror(2023123108);
            if fsym.LinkingData.ExeFunctionIndex<>-1 then
              internalerror(2023123109);
            if fsym.LinkingData.ExeTypeIndex<>-1 then
              internalerror(2023123109);
            fsym.LinkingData.ExeTypeIndex:=FFuncTypes.AddOrGetFuncType(fsym.LinkingData.FuncType);
            fsym.LinkingData.ExeFunctionIndex:=i+Length(FFunctionImports);
            if assigned(exemap) then
              begin
                exemap.Add('  Function[' + tostr(fsym.LinkingData.ExeFunctionIndex) + '] ' + fsym.Name + fsym.LinkingData.FuncType.ToString);
              end;
            AddToFunctionNameMap(fsym.LinkingData.ExeFunctionIndex,fsym.Name);
          end;
        { set ExeFunctionIndex to the alias symbols as well }
        for i:=0 to ObjDataList.Count-1 do
          begin
            objdata:=TObjData(ObjDataList[i]);
            for j:=0 to objdata.ObjSymbolList.Count-1 do
              begin
                fsym:=TWasmObjSymbol(objdata.ObjSymbolList[j]);
                if assigned(fsym.objsection) and fsym.objsection.USed and (fsym.typ=AT_FUNCTION) and (fsym.LinkingData.ExeFunctionIndex=-1) then
                  begin
                    fsym.LinkingData.ExeFunctionIndex:=TWasmObjSection(fsym.objsection).MainFuncSymbol.LinkingData.ExeFunctionIndex;
                    if fsym.LinkingData.ExeFunctionIndex=-1 then
                      internalerror(2024010102);
                  end;
              end;
          end;
      end;

    procedure TWasmExeOutput.PrepareTags;
      var
        exesec: TExeSection;
        i, j: Integer;
        objsec: TWasmObjSection;
        fsym: TWasmObjSymbol;
        objdata: TObjData;
      begin
        exesec:=FindExeSection('.wasm_tags');
        if not assigned(exesec) then
          exit;
        if assigned(exemap) then
          begin
            exemap.Add('');
            exemap.Add('Tags, defined in this module:');
          end;
        for i:=0 to exesec.ObjSectionList.Count-1 do
          begin
            objsec:=TWasmObjSection(exesec.ObjSectionList[i]);
            fsym:=objsec.MainFuncSymbol;
            if not assigned(fsym) then
              internalerror(2024010703);
            if not assigned(fsym.LinkingData.FuncType) then
              internalerror(2024010704);
            if fsym.LinkingData.ExeTagIndex<>-1 then
              internalerror(2024010705);
            if fsym.LinkingData.ExeTypeIndex<>-1 then
              internalerror(2024010706);
            fsym.LinkingData.ExeTypeIndex:=FFuncTypes.AddOrGetFuncType(fsym.LinkingData.FuncType);
            fsym.LinkingData.ExeTagIndex:=i+Length(FTagImports);
            if assigned(exemap) then
              begin
                exemap.Add('  Tag[' + tostr(fsym.LinkingData.ExeTagIndex) + '] ' + fsym.Name + fsym.LinkingData.FuncType.ToString);
              end;
          end;
        { set ExeTagIndex to the alias symbols as well }
        for i:=0 to ObjDataList.Count-1 do
          begin
            objdata:=TObjData(ObjDataList[i]);
            for j:=0 to objdata.ObjSymbolList.Count-1 do
              begin
                fsym:=TWasmObjSymbol(objdata.ObjSymbolList[j]);
                if assigned(fsym.objsection) and fsym.objsection.USed and (fsym.typ=AT_WASM_EXCEPTION_TAG) and (fsym.LinkingData.ExeTagIndex=-1) then
                  begin
                    fsym.LinkingData.ExeTagIndex:=TWasmObjSection(fsym.objsection).MainFuncSymbol.LinkingData.ExeTagIndex;
                    if fsym.LinkingData.ExeTagIndex=-1 then
                      internalerror(2024010707);
                  end;
              end;
          end;
      end;

    function TWasmExeOutput.AddOrGetIndirectFunctionTableIndex(FuncIdx: Integer): integer;
      var
        i: Integer;
      begin
        for i:=1 to length(FIndirectFunctionTable)-1 do
          if FIndirectFunctionTable[i].FuncIdx=FuncIdx then
            begin
              Result:=i;
              exit;
            end;
        SetLength(FIndirectFunctionTable,Length(FIndirectFunctionTable)+1);
        Result:=High(FIndirectFunctionTable);
        FIndirectFunctionTable[Result].FuncIdx:=FuncIdx;
      end;

    procedure TWasmExeOutput.SetStackPointer;
      var
        BssSec: TExeSection;
        StackStart, InitialStackPtrAddr: QWord;
      begin
        BssSec:=FindExeSection('.bss');
        InitialStackPtrAddr := (BssSec.MemPos+BssSec.Size+stacksize+15) and (not 15);
        FMinMemoryPages := Max(
          QWord(Align(QWord(InitialStackPtrAddr),QWord(WasmPageSize)) div WasmPageSize),
          QWord(Align(QWord(heapsize),QWord(WasmPageSize)) div WasmPageSize));
        FStackPointerSym.LinkingData.GlobalInitializer.init_i32:=Int32(InitialStackPtrAddr);
      end;

    procedure TWasmExeOutput.SetTlsSizeAlignAndBase;
      var
        TBssSec: TExeSection;
      begin
        if not (ts_wasm_threads in current_settings.targetswitches) then
          exit;
        TBssSec:=FindExeSection('.tbss');
        FTlsSizeSym.LinkingData.GlobalInitializer.init_i32:=Int32(TBssSec.Size);
        FTlsAlignSym.LinkingData.GlobalInitializer.init_i32:=Int32(TBssSec.SecAlign);
        FTlsBaseSym.LinkingData.GlobalInitializer.init_i32:=Int32(TBssSec.MemPos);
      end;

    procedure TWasmExeOutput.SetThreadVarGlobalsInitValues;
      var
        exesec: TExeSection;
        i: Integer;
        objsec: TWasmObjSection;
        objsym: TWasmObjSymbol;
      begin
        if not (ts_wasm_threads in current_settings.targetswitches) then
          exit;
        exesec:=FindExeSection('.wasm_globals');
        if not assigned(exesec) then
          internalerror(2024010112);
        for i:=0 to exesec.ObjSectionList.Count-1 do
          begin
            objsec:=TWasmObjSection(exesec.ObjSectionList[i]);
            objsym:=objsec.MainFuncSymbol;
            if Assigned(objsym.TlsDataSym) then
              begin
                objsym.LinkingData.GlobalInitializer.typ:=wbt_i32;
                objsym.LinkingData.GlobalInitializer.init_i32:=objsym.TlsDataSym.offset+objsym.TlsDataSym.objsection.MemPos;
              end;
          end;
      end;

    procedure TWasmExeOutput.GenerateCode_InitTls;
      var
        Sec: TObjSection;
        globalexesec: TExeSection;
        i: Integer;
        globalobjsec: TWasmObjSection;
        globalobjsym: TWasmObjSymbol;
        OffsetInTls: QWord;
      begin
        if not (ts_wasm_threads in current_settings.targetswitches) then
          exit;

        globalexesec:=FindExeSection('.wasm_globals');
        if not assigned(globalexesec) then
          internalerror(2024010112);

        Sec:=FInitTlsFunctionSym.objsection;
        Sec.SecOptions:=Sec.SecOptions+[oso_Data];

        { locals }
        Sec.writeUInt8($00);

        { local.get 0 }
        Sec.writeUInt16BE($2000);
        { global.set $__tls_base }
        Sec.writeUInt8($24);
        WriteUleb(sec,FTlsBaseSym.offset+FTlsBaseSym.objsection.MemPos);

        for i:=0 to globalexesec.ObjSectionList.Count-1 do
          begin
            globalobjsec:=TWasmObjSection(globalexesec.ObjSectionList[i]);
            globalobjsym:=globalobjsec.MainFuncSymbol;
            if Assigned(globalobjsym.TlsDataSym) then
              begin
                OffsetInTls:=globalobjsym.TlsDataSym.offset+globalobjsym.TlsDataSym.objsection.MemPos-globalobjsym.TlsDataSym.objsection.ExeSection.MemPos;
                { local.get 0 }
                Sec.writeUInt16BE($2000);
                if OffsetInTls<>0 then
                  begin
                    { i32.const $OffsetInTls }
                    Sec.writeUInt8($41);
                    WriteSleb(Sec,Int32(OffsetInTls));
                    { i32.add }
                    Sec.writeUInt8($6A);
                  end;
                { global.set y }
                Sec.writeUInt8($24);
                WriteUleb(sec,globalobjsym.offset+globalobjsym.objsection.MemPos);
              end;
          end;

        Sec.writeUInt8($0B);  { end }
      end;

    procedure TWasmExeOutput.GenerateCode_InitSharedMemory;
      const
        InitFlagOfs=256;
      var
        Sec: TObjSection;
        DataSecName: string;
        DataSecIdx: Integer;
        ExeSec: TExeSection;
      begin
        if not (ts_wasm_threads in current_settings.targetswitches) then
          exit;
        Sec:=FInitSharedMemoryFunctionSym.objsection;
        Sec.SecOptions:=Sec.SecOptions+[oso_Data];

        { locals }
        Sec.writeUInt8($00);

        { block }
        Sec.writeUInt16BE($0240);
        { block }
        Sec.writeUInt16BE($0240);
        { block }
        Sec.writeUInt16BE($0240);

        { i32.const $InitFlag }
        Sec.writeUInt8($41);
        WriteSleb(sec,InitFlagOfs);
        { i32.const 0 }
        Sec.writeUInt16BE($4100);
        { i32.const 1 }
        Sec.writeUInt16BE($4101);
        { i32.atomic.rmw.cmpxchg 2 0 }
        Sec.writeUInt32BE($fe480200);
        { br_table 0 1 2 }
        Sec.writebytes(#$0e#$02#$00#$01#$02);
        { end }
        Sec.writeUInt8($0B);

        DataSecIdx:=-1;
        for DataSecName in DataSections do
          begin
            ExeSec:=FindExeSection(DataSecName);
            if Assigned(ExeSec) and (ExeSec.Size>0) then
              begin
                Inc(DataSecIdx);
                { i32.const $memPos }
                Sec.writeUInt8($41);
                WriteSleb(sec,Int32(ExeSec.MemPos));
                { i32.const 0 }
                Sec.writeUInt16BE($4100);
                { i32.const size }
                Sec.writeUInt8($41);
                WriteSleb(sec,Int32(ExeSec.Size));
                { memory.init $DataSecIdx 0 }
                Sec.writeUInt16BE($fc08);
                WriteUleb(sec,DataSecIdx);
                Sec.writeUInt8(0);
              end;
          end;

        { i32.const $InitFlag }
        Sec.writeUInt8($41);
        WriteSleb(sec,InitFlagOfs);
        { i32.const 2 }
        Sec.writeUInt16BE($4102);
        { i32.atomic.store 2 0 }
        Sec.writeUInt32BE($fe170200);
        { i32.const $InitFlag }
        Sec.writeUInt8($41);
        WriteSleb(sec,InitFlagOfs);
        { i32.const 4294967295 }
        Sec.writeUInt16BE($417f);
        { memory.atomic.notify 2 0 }
        Sec.writeUInt32BE($fe000200);
        { drop }
        Sec.writeUInt8($1A);
        { br 1 }
        Sec.writeUInt16BE($0C01);
        { end }
        Sec.writeUInt8($0B);
        { i32.const $InitFlag }
        Sec.writeUInt8($41);
        WriteSleb(sec,InitFlagOfs);
        { i32.const 1 }
        Sec.writeUInt16BE($4101);
        { i64.const -1 }
        Sec.writeUInt16BE($427f);
        { memory.atomic.wait32 2 0 }
        Sec.writeUInt32BE($fe010200);
        { drop }
        Sec.writeUInt8($1A);
        { end }
        Sec.writeUInt8($0B);
        DataSecIdx:=-1;
        for DataSecName in DataSections do
          begin
            ExeSec:=FindExeSection(DataSecName);
            if Assigned(ExeSec) and (ExeSec.Size>0) then
              begin
                Inc(DataSecIdx);
                { data.drop $DataSecIdx }
                Sec.writeUInt16BE($fc09);
                WriteUleb(sec,DataSecIdx);
              end;
          end;
        { end }
        Sec.writeUInt8($0B);
      end;

    procedure TWasmExeOutput.GenerateCode_InvokeHelper;
      var
        Sec: TObjSection;
        IndirectFunctionTableMap: array of Integer;

      procedure InvokeFuncType(typidx: Integer; islast: Boolean);
        var
          ft: TWasmFuncType;
          i, nextofs: Integer;
        begin
          ft:=FFuncTypes[typidx];
          for i:=0 to Length(ft.results)-1 do
            { local.get 2 }
            Sec.writeUInt16BE($2002);
          nextofs:=0;
          for i:=0 to Length(ft.params)-1 do
            begin
              { local.get 1 }
              Sec.writeUInt16BE($2001);
              case ft.params[i] of
                wbt_i32:
                  begin
                    { i32.load nextofs }
                    Sec.writeUInt16BE($2802);
                    WriteUleb(Sec, nextofs);
                    Inc(nextofs,4);
                  end;
                wbt_i64:
                  begin
                    { i64.load nextofs }
                    Sec.writeUInt16BE($2902);
                    WriteUleb(Sec, nextofs);
                    Inc(nextofs,8);
                  end;
                wbt_f32:
                  begin
                    { f32.load nextofs }
                    Sec.writeUInt16BE($2A02);
                    WriteUleb(Sec, nextofs);
                    Inc(nextofs,4);
                  end;
                wbt_f64:
                  begin
                    { f64.load nextofs }
                    Sec.writeUInt16BE($2B02);
                    WriteUleb(Sec, nextofs);
                    Inc(nextofs,8);
                  end;
                wbt_v128:
                  begin
                    { v128.load nextofs }
                    Sec.writeUInt16BE($FD00);
                    Sec.writeUInt8($02);  { align: 4 bytes }
                    WriteUleb(Sec, nextofs);
                    Inc(nextofs,16);
                  end;
                wbt_externref,
                wbt_funcref:
                  begin
                    { unreachable }
                    Sec.writeUInt8($00);
                  end;
                else
                  internalerror(2025012501);
              end;
            end;
          { local.get 0 }
          Sec.writeUInt16BE($2000);
          { call_indirect }
          Sec.writeUInt8($11);
          WriteUleb(Sec,typidx);
          Sec.writeUInt8($0);  { table index 0 }
          nextofs:=0;
          for i:=0 to Length(ft.results)-1 do
            begin
              case ft.results[i] of
                wbt_i32:
                  begin
                    { i32.store nextofs }
                    Sec.writeUInt16BE($3602);
                    WriteUleb(Sec, nextofs);
                    Inc(nextofs,4);
                  end;
                wbt_i64:
                  begin
                    { i64.store nextofs }
                    Sec.writeUInt16BE($3702);
                    WriteUleb(Sec, nextofs);
                    Inc(nextofs,8);
                  end;
                wbt_f32:
                  begin
                    { f32.store nextofs }
                    Sec.writeUInt16BE($3802);
                    WriteUleb(Sec, nextofs);
                    Inc(nextofs,4);
                  end;
                wbt_f64:
                  begin
                    { f64.store nextofs }
                    Sec.writeUInt16BE($3902);
                    WriteUleb(Sec, nextofs);
                    Inc(nextofs,8);
                  end;
                wbt_v128:
                  begin
                    { v128.store nextofs }
                    Sec.writeUInt16BE($FD0B);
                    Sec.writeUInt8($02);  { align: 4 bytes }
                    WriteUleb(Sec, nextofs);
                    Inc(nextofs,16);
                  end;
                wbt_externref,
                wbt_funcref:
                  begin
                    { unreachable }
                    Sec.writeUInt8($00);
                  end;
                else
                  internalerror(2025012501);
              end;
            end;
          if not islast then
            { return }
            Sec.writeUInt8($0F);
        end;

      function FuncIdx2TypeIdx(fi: Integer): Integer;
        var
          exesec: TExeSection;
          objsec: TWasmObjSection;
          fsym: TWasmObjSymbol;
        begin
          if fi<Length(FFunctionImports) then
            Result:=FFunctionImports[fi].TypeIdx
          else
            begin
              exesec:=FindExeSection('.text');
              if not assigned(exesec) then
                internalerror(2023123106);
              objsec:=TWasmObjSection(exesec.ObjSectionList[fi-Length(FFunctionImports)]);
              fsym:=objsec.MainFuncSymbol;
              Result:=fsym.LinkingData.ExeTypeIndex;
            end;
        end;

      procedure WriteBrTable(l,h: Integer; addend: Integer=0);
        const
          { max len of br_table instruction }
          MaxLen=1000;
        var
          i, len, m: Integer;
        begin
          { local.get 0 }
          Sec.writeUInt16BE($2000);
          len:=h-l+1;
          if len<=MaxLen then
            begin
              if l>0 then
                begin
                  { i32.const l }
                  Sec.writeUInt8($41);
                  WriteSleb(sec,l);
                  { i32.sub }
                  Sec.writeUInt8($6B);
                end;
              { br_table }
              Sec.writeUInt8($0E);
              if h=high(IndirectFunctionTableMap) then
                begin
                  WriteUleb(Sec,len);
                  for i:=l to h do
                    WriteUleb(Sec,IndirectFunctionTableMap[i]+addend);
                  WriteUleb(Sec,addend);
                end
              else
                begin
                  WriteUleb(Sec,len-1);
                  for i:=l to h do
                    WriteUleb(Sec,IndirectFunctionTableMap[i]+addend);
                end;
            end
          else
            begin
              m:=(l+h) div 2;
              { i32.const m }
              Sec.writeUInt8($41);
              WriteSleb(sec,m);
              { i32.lt_u }
              Sec.writeUInt8($49);
              { if }
              Sec.writeUInt16BE($0440);
              WriteBrTable(l,m-1,addend+1);
              { else }
              Sec.writeUInt8($05);
              WriteBrTable(m,h,addend+1);
              { end }
              Sec.writeUInt8($0B);
            end;
        end;

      var
        exesym: TExeSymbol;
        objsym: TObjSymbol;
        i, j, TypIdx: Integer;
        InvokableTypeIndices: array of Integer;
      begin
        exesym:=TExeSymbol(ExeSymbolList.Find('fpc_wasm_invoke_helper'));
        if not Assigned(exesym) then
          exit;

        SetLength(IndirectFunctionTableMap, Length(FIndirectFunctionTable));
        SetLength(InvokableTypeIndices, 1);
        InvokableTypeIndices[0] := -1;
        for i:=1 to Length(FIndirectFunctionTable)-1 do
          begin
            IndirectFunctionTableMap[i]:=0;
            TypIdx := FuncIdx2TypeIdx(FIndirectFunctionTable[i].FuncIdx);
            for j := 1 to Length(InvokableTypeIndices)-1 do
              if InvokableTypeIndices[j]=TypIdx then
                begin
                  IndirectFunctionTableMap[i]:=j;
                  break;
                end;
            if IndirectFunctionTableMap[i]=0 then
              begin
                SetLength(InvokableTypeIndices,Length(InvokableTypeIndices)+1);
                InvokableTypeIndices[High(InvokableTypeIndices)]:=TypIdx;
                IndirectFunctionTableMap[i]:=High(InvokableTypeIndices);
              end;
          end;

        objsym:=exesym.ObjSymbol;
        Sec:=objsym.objsection;
        Sec.Size:=0;
        Sec.Data.reset;

        { locals }
        Sec.writeUInt8($00);

        for i:=1 to Length(InvokableTypeIndices)-1 do
          { block }
          Sec.writeUInt16BE($0240);

        { block }
        Sec.writeUInt16BE($0240);
        { local.get 0 + br_table }
        WriteBrTable(low(IndirectFunctionTableMap),high(IndirectFunctionTableMap));
        { end }
        Sec.writeUInt8($0B);
        { unreachable }
        Sec.writeUInt8($00);

        for i:=1 to Length(InvokableTypeIndices)-1 do
          begin
            { end }
            Sec.writeUInt8($0B);
            InvokeFuncType(InvokableTypeIndices[i],i=(Length(InvokableTypeIndices)-1));
          end;

        { end }
        Sec.writeUInt8($0B);
      end;

    procedure TWasmExeOutput.WriteExeSectionToDynArray(exesec: TExeSection; dynarr: tdynamicarray);
      var
        exesecdatapos: LongWord;
        i: Integer;
        objsec: TObjSection;
        dpos, pad: QWord;
      begin
        exesecdatapos:=dynarr.size;
        for i:=0 to exesec.ObjSectionList.Count-1 do
          begin
            objsec:=TObjSection(exesec.ObjSectionList[i]);
            if not (oso_data in objsec.secoptions) then
              internalerror(2024010104);
            if not assigned(objsec.data) then
              internalerror(2024010105);

            dpos:=objsec.MemPos-exesec.MemPos+exesecdatapos;
            pad:=dpos-dynarr.size;
            { objsection must be within SecAlign bytes from the previous one }
            if (dpos<dynarr.Size) or
              (pad>=max(objsec.SecAlign,1)) then
              internalerror(2024010106);
            writeZeros(dynarr,pad);

            objsec.data.seek(0);
            CopyDynamicArray(objsec.data,dynarr,objsec.data.size);
          end;
        if (dynarr.size-exesecdatapos)<>exesec.Size then
          internalerror(2024010107);
      end;

    procedure TWasmExeOutput.WriteMap_TypeSection;
      var
        i: Integer;
      begin
        exemap.AddHeader('Type section');
        for i:=0 to FFuncTypes.Count-1 do
          exemap.Add('  Type[' + tostr(i) + '] ' + FFuncTypes.Items[i].ToString);
      end;

    procedure TWasmExeOutput.WriteMap_IndirectFunctionTable;
      var
        i: Integer;
      begin
        exemap.AddHeader('Indirect function table');
        for i:=1 to High(FIndirectFunctionTable) do
          exemap.Add('  Elem[' + tostr(i) + '] = Function[' + tostr(FIndirectFunctionTable[i].FuncIdx) + ']');
      end;


{****************************************************************************
                               TWasmAssembler
****************************************************************************}

    constructor TWasmAssembler.Create(info: pasminfo; smart:boolean);
      begin
        inherited;
        CObjOutput:=TWasmObjOutput;
      end;

{*****************************************************************************
                                  Initialize
*****************************************************************************}
{$ifdef wasm32}
    const
       as_wasm32_wasm_info : tasminfo =
          (
            id     : as_wasm32_wasm;
            idtxt  : 'WASM';
            asmbin : '';
            asmcmd : '';
            supported_targets : [system_wasm32_embedded,system_wasm32_wasi];
            flags : [af_outputbinary,af_smartlink_sections];
            labelprefix : '..@';
            labelmaxlen : -1;
            comment : '; ';
            dollarsign: '$';
          );
{$endif wasm32}

initialization
{$ifdef wasm32}
  RegisterAssembler(as_wasm32_wasm_info,TWasmAssembler);
{$endif wasm32}
end.