* emit a weak symbol for the exception tag, since that's what the LLVM linker

  wants to treat them as shared between .o files

compiler/aasmbase.pas

@@ -47,7 +47,8 @@ interface
          AB_TEMP,
          { a global symbol that points to another global symbol and is only used
            to allow indirect loading in case of packages and indirect imports }
-         AB_INDIRECT,AB_EXTERNAL_INDIRECT);
+         AB_INDIRECT,AB_EXTERNAL_INDIRECT,
+         AB_WEAK);
 
        TAsmsymtype=(
          AT_NONE,AT_FUNCTION,AT_DATA,AT_SECTION,AT_LABEL,
@@ -89,7 +90,7 @@ interface
        asmlabeltypeprefix : array[TAsmLabeltype] of string[2] = ('j','a','d','l','f','t','c','eb','ee');
        asmsymbindname : array[TAsmsymbind] of string[23] = ('none', 'external','common',
        'local','global','weak external','private external','lazy','import','internal temp',
-       'indirect','external indirect');
+       'indirect','external indirect','weak');
        asmsymbindindirect = [AB_INDIRECT,AB_EXTERNAL_INDIRECT];
 
     type

compiler/aasmtai.pas

@@ -607,6 +607,7 @@ interface
           has_value : boolean;
           constructor Create(_sym:tasmsymbol;siz:longint);
           constructor Create_Global(_sym:tasmsymbol;siz:longint);
+          constructor Create_Weak(_sym:tasmsymbol;siz:longint);
           constructor Createname(const _name : string;_symtyp:Tasmsymtype;siz:longint;def:tdef);
           constructor Createname_global(const _name : string;_symtyp:Tasmsymtype;siz:longint;def:tdef);
           constructor Createname_hidden(const _name : string;_symtyp:Tasmsymtype;siz:longint;def:tdef);
@@ -1449,6 +1450,19 @@ implementation
       end;
 
 
+    constructor tai_symbol.Create_Weak(_sym:tasmsymbol;siz:longint);
+      begin
+        inherited Create;
+        typ:=ait_symbol;
+        sym:=_sym;
+        size:=siz;
+        if not(sym.bind in [AB_NONE,AB_WEAK_EXTERNAL]) then
+          internalerror(2021092801);
+        sym.bind:=AB_WEAK;
+        is_global:=false;
+      end;
+
+
     constructor tai_symbol.Createname(const _name : string;_symtyp:Tasmsymtype;siz:longint;def:tdef);
       begin
          inherited Create;

compiler/ogbase.pas

@@ -842,7 +842,7 @@ implementation
 
     procedure TObjSymbol.SetAddress(apass:byte;aobjsec:TObjSection;abind:TAsmsymbind;atyp:Tasmsymtype);
       begin
-        if not(abind in [AB_GLOBAL,AB_PRIVATE_EXTERN,AB_LOCAL,AB_COMMON,AB_IMPORT]) then
+        if not(abind in [AB_GLOBAL,AB_PRIVATE_EXTERN,AB_LOCAL,AB_COMMON,AB_IMPORT,AB_WEAK]) then
           internalerror(200603016);
         if not assigned(aobjsec) then
           internalerror(200603017);

compiler/ogwasm.pas

@@ -1497,6 +1497,8 @@ implementation
                   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);
                 WriteUleb(FWasmSymbolTable,objsym.TagIndex);

compiler/wasm32/nwasmflw.pas

@@ -691,7 +691,7 @@ implementation
         hlcg.g_exception_reason_save_const(current_asmdata.CurrAsmList,exceptionreasontype,0,excepttemps.reasonbuf);
         current_asmdata.CurrAsmList.concat(taicpu.op_const(a_br,4)); // jump to the 'finally' section
 
-        current_asmdata.CurrAsmList.concat(taicpu.op_sym(a_catch,current_asmdata.RefAsmSymbol(FPC_EXCEPTION_TAG_SYM,AT_WASM_EXCEPTION_TAG)));
+        current_asmdata.CurrAsmList.concat(taicpu.op_sym(a_catch,current_asmdata.WeakRefAsmSymbol(FPC_EXCEPTION_TAG_SYM,AT_WASM_EXCEPTION_TAG)));
         thlcgwasm(hlcg).decblock;
         { exceptionreason:=1 (exception) }
         hlcg.g_exception_reason_save_const(current_asmdata.CurrAsmList,exceptionreasontype,1,excepttemps.reasonbuf);

compiler/wasm32/nwasminl.pas

@@ -159,7 +159,7 @@ implementation
     procedure twasminlinenode.second_throw_fpcexception;
       begin
         location_reset(location,LOC_VOID,OS_NO);
-        current_asmdata.CurrAsmList.Concat(taicpu.op_sym(a_throw,current_asmdata.RefAsmSymbol(FPC_EXCEPTION_TAG_SYM,AT_WASM_EXCEPTION_TAG)));
+        current_asmdata.CurrAsmList.Concat(taicpu.op_sym(a_throw,current_asmdata.WeakRefAsmSymbol(FPC_EXCEPTION_TAG_SYM,AT_WASM_EXCEPTION_TAG)));
       end;
 
 

compiler/wasm32/nwasmutil.pas

@@ -74,7 +74,7 @@ implementation
       if ts_wasm_native_exceptions in current_settings.targetswitches then
         begin
           list.Concat(tai_tagtype.create(FPC_EXCEPTION_TAG_SYM, []));
-          list.Concat(tai_symbol.Create(current_asmdata.DefineAsmSymbol(FPC_EXCEPTION_TAG_SYM,AB_LOCAL,AT_WASM_EXCEPTION_TAG,nil),0));
+          list.Concat(tai_symbol.Create_Weak(current_asmdata.WeakRefAsmSymbol(FPC_EXCEPTION_TAG_SYM,AT_WASM_EXCEPTION_TAG),0));
         end;
 
       for i:=0 to current_module.deflist.Count-1 do