add AOT data segment size using llvm-size tool

src/mono/wasm/build/WasmApp.Native.targets

@@ -149,10 +149,6 @@
     <Error Condition="'$(_IsEMSDKMissing)' == 'true'"
            Text="$(_EMSDKMissingErrorMessage) Emscripten SDK is required for building native files." />
 
-    <WasmCalculateInitialHeapSize Assemblies="@(WasmAssembliesToBundle)">
-      <Output TaskParameter="TotalSize" PropertyName="_WasmCalculatedInitialHeapSize" />
-    </WasmCalculateInitialHeapSize>
-
     <PropertyGroup>
       <_MonoAotCrossCompilerPath>@(MonoAotCrossCompiler->WithMetadataValue('RuntimeIdentifier','browser-wasm'))</_MonoAotCrossCompilerPath>
       <_EmccDefaultFlagsRsp>$([MSBuild]::NormalizePath($(_WasmRuntimePackSrcDir), 'emcc-default.rsp'))</_EmccDefaultFlagsRsp>
@@ -191,9 +187,6 @@
       <_EmccCompileBitcodeRsp>$(_WasmIntermediateOutputPath)emcc-compile-bc.rsp</_EmccCompileBitcodeRsp>
       <_EmccLinkRsp>$(_WasmIntermediateOutputPath)emcc-link.rsp</_EmccLinkRsp>
 
-      <EmccInitialHeapSize Condition="'$(EmccInitialHeapSize)' == ''">$(EmccTotalMemory)</EmccInitialHeapSize>
-      <EmccInitialHeapSize Condition="'$(EmccInitialHeapSize)' == '' and '$(_WasmCalculatedInitialHeapSize)' != '' and $(_WasmCalculatedInitialHeapSize) > 16777216">$(_WasmCalculatedInitialHeapSize)</EmccInitialHeapSize>
-      <EmccInitialHeapSize Condition="'$(EmccInitialHeapSize)' == ''">16777216</EmccInitialHeapSize>
     </PropertyGroup>
 
     <ItemGroup>
@@ -236,7 +229,6 @@
       <_EmccLDFlags Include="-s ASSERTIONS=$(_EmccAssertionLevelDefault)" Condition="'$(_WasmDevel)' == 'true'" />
       <_EmccLDFlags Include="@(_EmccCommonFlags)" />
       <_EmccLDSFlags Include="-Wl,--allow-undefined" />
-      <_EmccLDSFlags Include="-s INITIAL_MEMORY=$(EmccInitialHeapSize)" />
 
       <!-- ILLinker should have removed unused imports, so error for Publish -->
       <_EmccLDSFlags Include="-s ERROR_ON_UNDEFINED_SYMBOLS=0" Condition="'$(WasmBuildingForNestedPublish)' != 'true'" />
@@ -377,7 +369,41 @@
     </ItemGroup>
   </Target>
 
-  <Target Name="_WasmWriteRspFilesForLinking" DependsOnTargets="_CheckEmccIsExpectedVersion">
+  <Target Name="_WasmCalculateMemorySize" DependsOnTargets="_CheckEmccIsExpectedVersion">
+    <ItemGroup>
+      <_AOTObjectFile Include="%(_BitcodeFile.ObjectFile)" />
+    </ItemGroup>
+
+    <!-- for AOT builds we use llvm-size tool to collect size of the DATA segment in each object file -->
+    <Exec Command="llvm-size$(_ExeExt) -d --format=sysv @(_AOTObjectFile, ' ')"
+          Condition="'$(_WasmShouldAOT)' == 'true'"
+          IgnoreStandardErrorWarningFormat="true"
+          ConsoleToMsBuild="true"
+          StandardOutputImportance="low" StandardErrorImportance="low"
+          EnvironmentVariables="@(EmscriptenEnvVars)" >
+      <Output TaskParameter="ConsoleOutput" ItemName="LlvmAotSizeOutput" />
+    </Exec>
+    <ItemGroup Condition="'$(_WasmShouldAOT)' == 'true'">
+      <AOTDataSegments Condition="$([System.String]::Copy('%(LlvmAotSizeOutput.Identity)').StartsWith('DATA '))"
+        Include="$([System.String]::Copy('%(LlvmAotSizeOutput.Identity)').Replace(&quot;DATA &quot;, &quot;&quot;).Replace(&quot; 0&quot;, &quot;&quot;).Trim())" />
+    </ItemGroup>
+
+    <WasmCalculateInitialHeapSize
+        Assemblies="@(WasmAssembliesToBundle)"
+        AOTDataSegments="@(AOTDataSegments)">
+      <Output TaskParameter="InitialHeapSize" PropertyName="_WasmCalculatedInitialHeapSize" />
+    </WasmCalculateInitialHeapSize>
+    <PropertyGroup>
+      <EmccInitialHeapSize Condition="'$(EmccInitialHeapSize)' == ''">$(EmccTotalMemory)</EmccInitialHeapSize>
+      <EmccInitialHeapSize Condition="'$(EmccInitialHeapSize)' == '' and '$(_WasmCalculatedInitialHeapSize)' != '' and $(_WasmCalculatedInitialHeapSize) > 16777216">$(_WasmCalculatedInitialHeapSize)</EmccInitialHeapSize>
+      <EmccInitialHeapSize Condition="'$(EmccInitialHeapSize)' == ''">16777216</EmccInitialHeapSize>
+    </PropertyGroup>
+    <ItemGroup>
+      <_EmccLDSFlags Include="-s INITIAL_MEMORY=$(EmccInitialHeapSize)" />
+    </ItemGroup>
+  </Target>
+
+  <Target Name="_WasmWriteRspFilesForLinking" DependsOnTargets="_CheckEmccIsExpectedVersion;_WasmCalculateMemorySize">
     <PropertyGroup>
       <_WasmEHLib Condition="'$(WasmEnableExceptionHandling)' == 'true'">libmono-wasm-eh-wasm.a</_WasmEHLib>
       <_WasmEHLib Condition="'$(WasmEnableExceptionHandling)' != 'true'">libmono-wasm-eh-js.a</_WasmEHLib>

src/tasks/WasmAppBuilder/WasmCalculateInitialHeapSize.cs

@@ -10,19 +10,24 @@
 using Microsoft.Build.Framework;
 using Microsoft.Build.Utilities;
 
-/// <summary>estimate the total memory needed for the assemblies.</summary>
+/// <summary>estimate the total memory needed for the assemblies and AOT data segments.</summary>
 public class WasmCalculateInitialHeapSize : Task
 {
     [Required]
     [NotNull]
     public string[]? Assemblies { get; set; }
 
+    [Required]
+    public string[]? AOTDataSegments { get; set; }
+
     [Output]
-    public long? TotalSize { get; private set; }
+    public long? InitialHeapSize { get; private set; }
 
     public override bool Execute ()
     {
         long totalDllSize=0;
+        long totalDataSize=0;
+
         foreach (var asm in Assemblies)
         {
             var info = new FileInfo(asm);
@@ -34,12 +39,22 @@ public override bool Execute ()
             totalDllSize += info.Length;
         }
 
+        // during non-AOT builds, AOTDataSegments is null
+        if (AOTDataSegments != null) 
+        {
+            foreach (var segment in AOTDataSegments)
+            {
+                totalDataSize += long.Parse(segment);
+            }
+        }
+
         // this is arbitrary guess about memory overhead of the runtime, after the assemblies are loaded
         const double extraMemoryRatio = 1.2;
-        long memorySize = (long) (totalDllSize * extraMemoryRatio);
+        // plus size of data segments generated by AOT
+        long memorySize = totalDataSize + (long) (totalDllSize * extraMemoryRatio);
 
         // round it up to 64KB page size for wasm
-        TotalSize = (memorySize + 0x10000) & 0xFFFF0000;
+        InitialHeapSize = (memorySize + 0x10000) & 0xFFFF0000;
 
         return true;
     }