* WebAssembly internal linker: refactored the writing of the memory section and

  the memory import section: introduced a TWasmMemoryType record, and structures
  for holding the memory entries in the import and memory sections, instead of
  writing them in an ad hoc manner. The memory information in the linker map
  file is now also a little more detailed.

compiler/ogwasm.pas

@@ -284,6 +284,13 @@ interface
           FuncIdx: Integer;
         end;
 
+        FImportedMemories: array of record
+          ModName: ansistring;
+          Name: ansistring;
+          MemType: TWasmMemoryType;
+        end;
+        FMemories: array of TWasmMemoryType;
+
         FRelocationPass: Integer;
         FWasmSections: array [TWasmSectionID] of tdynamicarray;
         FWasmCustomSections: array [TWasmCustomSectionType] of tdynamicarray;
@@ -320,6 +327,8 @@ interface
         procedure GenerateCode_InitSharedMemory;
         procedure GenerateCode_InvokeHelper;
         procedure WriteExeSectionToDynArray(exesec: TExeSection; dynarr: tdynamicarray);
+        procedure WriteMemoryTo(dest: tdynamicarray;const MemType:TWasmMemoryType);
+        function Memory2String(const MemType:TWasmMemoryType):string;
         procedure WriteMap_TypeSection;
         procedure WriteMap_IndirectFunctionTable;
       protected
@@ -4847,28 +4856,22 @@ implementation
       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;
+          imports_count:=Length(FImportedMemories)+Length(FFunctionImports);
           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(FImportedMemories)-1 do
+            with FImportedMemories[i] do
+              begin
+                WriteName(FWasmSections[wsiImport],ModName);
+                WriteName(FWasmSections[wsiImport],Name);
+                WriteByte(FWasmSections[wsiImport],$02);  { mem }
+                WriteMemoryTo(FWasmSections[wsiImport],MemType);
+                if assigned(exemap) then
+                  exemap.Add('  Memory['+tostr(i)+'] '+Memory2String(MemType)+' <- '+ModName+'.'+Name);
+              end;
           for i:=0 to Length(FFunctionImports)-1 do
             with FFunctionImports[i] do
               begin
@@ -5214,6 +5217,21 @@ implementation
             end;
         end;
 
+      procedure WriteMemorySection;
+        var
+          i: Integer;
+        begin
+          if assigned(exemap) then
+            exemap.AddHeader('Memory section');
+          WriteUleb(FWasmSections[wsiMemory],Length(FMemories));
+          for i:=low(FMemories) to high(FMemories) do
+            begin
+              WriteMemoryTo(FWasmSections[wsiMemory],FMemories[i]);
+              if assigned(exemap) then
+                exemap.Add('  Memory['+tostr(i+Length(FImportedMemories))+'] '+Memory2String(FMemories[i]));
+            end;
+        end;
+
       var
         cust_sec: TWasmCustomSectionType;
       begin
@@ -5230,6 +5248,36 @@ implementation
         GenerateCode_InitTls;
         GenerateCode_InitSharedMemory;
 
+        if ts_wasm_threads in current_settings.targetswitches then
+          begin
+            SetLength(FImportedMemories,1);
+            with FImportedMemories[0] do
+              begin
+                ModName:='env';
+                Name:='memory';
+                with MemType do
+                  begin
+                    Flags:=[wmfShared,wmfHasMaximumBound];
+                    MinPages:=FMinMemoryPages;
+                    MaxPages:=Max(FMinMemoryPages,FMaxMemoryPages);
+                  end;
+              end;
+          end
+        else
+          begin
+            SetLength(FMemories,1);
+            with FMemories[0] do
+              begin
+                Flags:=[];
+                MinPages:=FMinMemoryPages;
+                if FMaxMemoryPages>=FMinMemoryPages then
+                  begin
+                    Include(Flags,wmfHasMaximumBound);
+                    MaxPages:=FMaxMemoryPages;
+                  end;
+              end;
+          end;
+
         FFuncTypes.WriteTo(FWasmSections[wsiType]);
         WriteImportSection;
         WriteCodeSegments;
@@ -5238,27 +5286,8 @@ implementation
         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;
+        if Length(FMemories)>0 then
+          WriteMemorySection;
 
         WriteExportSection;
 
@@ -6402,6 +6431,32 @@ implementation
           internalerror(2024010107);
       end;
 
+    procedure TWasmExeOutput.WriteMemoryTo(dest: tdynamicarray; const MemType: TWasmMemoryType);
+      begin
+        WriteByte(dest,Byte(MemType.Flags));
+        WriteUleb(dest,MemType.MinPages);
+        if wmfHasMaximumBound in MemType.Flags then
+          WriteUleb(dest,MemType.MaxPages);
+        { todo: wmfCustomPageSize }
+      end;
+
+    function TWasmExeOutput.Memory2String(const MemType: TWasmMemoryType): string;
+      begin
+        Result:='index type: ';
+        if wmfMemory64 in MemType.Flags then
+          Result:=Result+'i64'
+        else
+          Result:=Result+'i32';
+        Result:=Result+', pages: initial='+tostr(MemType.MinPages);
+        if wmfHasMaximumBound in MemType.Flags then
+          Result:=Result+' max='+tostr(MemType.MaxPages);
+        if wmfShared in MemType.Flags then
+          Result:=Result+', shared'
+        else
+          Result:=Result+', unshared';
+        { todo: wmfCustomPageSize }
+      end;
+
     procedure TWasmExeOutput.WriteMap_TypeSection;
       var
         i: Integer;

compiler/wasm32/cpubase.pas

@@ -142,6 +142,19 @@ uses
       TWasmResultType = array of TWasmBasicType;
       TWasmLocalsDynArray = array of TWasmBasicType;
 
+      TWasmMemoryFlag = (
+        wmfHasMaximumBound,
+        wmfShared,
+        wmfMemory64,
+        wmfCustomPageSize
+      );
+      TWasmMemoryFlags = set of TWasmMemoryFlag;
+      TWasmMemoryType = record
+        Flags: TWasmMemoryFlags;
+        MinPages, MaxPages: UInt64;
+        PageSize: UInt32;
+      end;
+
       { TWasmFuncType }
 
       PWasmFuncType = ^TWasmFuncType;