[wasm] Use ordinary struct alignment for Int128/UInt128 on wasm#131421

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
lewing wants to merge 2 commits into from
Closed

[wasm] Use ordinary struct alignment for Int128/UInt128 on wasm #131421

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
6189b46
[wasm] Use ordinary struct alignment for Int128/UInt128 on wasm
lewing Jul 27, 2026
5fe365d
Add Wasm32 cases to the Int128/UInt128 architecture layout tests
lewing Jul 27, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 1 addition & 1 deletion src/coreclr/tools/Common/Compiler/Int128FieldLayoutAlgorithm.cs
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -31,7 +31,7 @@ public override ComputedInstanceFieldLayout ComputeInstanceLayout(DefType defTyp
ComputedInstanceFieldLayout layoutFromMetadata = _fallbackAlgorithm.ComputeInstanceLayout(defType, layoutKind);

// 32bit platforms use standard metadata layout engine
if (defType.Context.Target.Architecture == TargetArchitecture.ARM)
if (defType.Context.Target.Architecture is TargetArchitecture.ARM or TargetArchitecture.Wasm32)
{
Comment on lines 33 to 35

@lewinglewingJul 27, 2026

Copy link
Copy Markdown
MemberAuthor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Correct that the comment is imprecise — X86 is 32-bit and does take the 16-byte override. That imprecision predates this change though, and the condition it describes is right there on the next line, so I'd rather not expand it here: rewording a pre-existing comment is unrelated churn, and per repo convention comments are kept minimal because inaccurate ones mislead and need maintenance.

Happy to fix it if a maintainer would prefer.

Note

This comment was generated by GitHub Copilot.

layoutFromMetadata.LayoutAbiStable = true;
layoutFromMetadata.IsInt128OrHasInt128Fields = true;
Comment on lines +34 to 37

@lewinglewingJul 27, 2026

Copy link
Copy Markdown
MemberAuthor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Added Wasm32 cases to TestAlignmentBehavior_AutoAlignmentRulesWithOSDependence in 5fe365d. Both fail without the layout change (alignment 16 rather than 8), so they actually guard the new branch rather than just documenting it.

Note

This comment was generated by GitHub Copilot.

Expand Down
13 changes: 13 additions & 0 deletions src/coreclr/tools/aot/ILCompiler.TypeSystem.Tests/ArchitectureSpecificFieldLayoutTests.cs
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -22,6 +22,8 @@ public class ArchitectureSpecificFieldLayoutTests
private ModuleDesc _testModuleARM;
private TestTypeSystemContext _contextARM64;
private ModuleDesc _testModuleARM64;
private TestTypeSystemContext _contextWasm32;
private ModuleDesc _testModuleWasm32;

public ArchitectureSpecificFieldLayoutTests()
{
Expand DownExpand Up@@ -60,6 +62,12 @@ public ArchitectureSpecificFieldLayoutTests()
_contextARM64.SetSystemModule(systemModuleARM64);

_testModuleARM64 = systemModuleARM64;

_contextWasm32 = new TestTypeSystemContext(TargetArchitecture.Wasm32);
var systemModuleWasm32 = _contextWasm32.CreateModuleForSimpleName("CoreTestAssembly");
_contextWasm32.SetSystemModule(systemModuleWasm32);

_testModuleWasm32 = systemModuleWasm32;
}

[Fact]
Expand DownExpand Up@@ -501,11 +509,13 @@ public void TestAlignmentBehavior_AutoAlignmentRules(string wrapperType, int[] a
[InlineData("StructStructByte_Int128StructAuto", "X86", 16, 32)]
[InlineData("StructStructByte_Int128StructAuto", "X64Linux", 16, 32)]
[InlineData("StructStructByte_Int128StructAuto", "X64Windows", 16, 32)]
[InlineData("StructStructByte_Int128StructAuto", "Wasm32", 8, 24)]
[InlineData("StructStructByte_UInt128StructAuto", "ARM64", 16, 32)]
[InlineData("StructStructByte_UInt128StructAuto", "ARM", 8, 24)]
[InlineData("StructStructByte_UInt128StructAuto", "X86", 16, 32)]
[InlineData("StructStructByte_UInt128StructAuto", "X64Linux", 16, 32)]
[InlineData("StructStructByte_UInt128StructAuto", "X64Windows", 16, 32)]
[InlineData("StructStructByte_UInt128StructAuto", "Wasm32", 8, 24)]
// Variation of TestAlignmentBehavior_AutoAlignmentRules above that is able to deal with os specific behavior
public void TestAlignmentBehavior_AutoAlignmentRulesWithOSDependence(string wrapperType, string osArch, int alignment, int size)
{
Expand All@@ -530,6 +540,9 @@ public void TestAlignmentBehavior_AutoAlignmentRulesWithOSDependence(string wrap
case "X86":
testModule = _testModuleX86;
break;
case "Wasm32":
testModule = _testModuleWasm32;
break;
default:
throw new Exception();
}
Expand Down
3 changes: 2 additions & 1 deletion src/coreclr/vm/methodtablebuilder.cpp
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -10817,7 +10817,8 @@ void MethodTableBuilder::CheckForSystemTypes()
// even on X86
pLayout->SetAlignmentRequirement(16); // sizeof(__int128)
#elif defined(TARGET_WASM)
pLayout->SetAlignmentRequirement(16); // sizeof(v128)
// Wasm has no 128-bit scalar type to match, so use the natural field alignment.
pLayout->SetAlignmentRequirement(8);
#else
#error Unknown architecture
#endif // TARGET_64BIT
Comment on lines +10820 to 10824
Expand Down
Loading
, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
 blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

Skip to content
[wasm] Use ordinary struct alignment for Int128/UInt128 on wasm#131421

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

 Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and
privacy statement. We’ll occasionally send you account related emails.

Already on GitHub?
Sign in
to your account

 Closed

lewing
wants to merge
2
commits into

from

 Closed


[wasm] Use ordinary struct alignment for Int128/UInt128 on wasm
#131421
Show file tree
Hide file tree
 Changes from all commits
Commits

Show all changes


2 commits


Select commit
Hold shift + click to select a range
6189b46

[wasm] Use ordinary struct alignment for Int128/UInt128 on wasm


lewing Jul 27, 2026
5fe365d

Add Wasm32 cases to the Int128/UInt128 architecture layout tests


lewing Jul 27, 2026

File filter

Filter by extension
Filter by extension
Conversations

Failed to load comments. 
Loading
Jump to

Jump to file


Failed to load files. 
Loading
 Diff view

 Diff view


2 changes: 1 addition & 1 deletion
src/coreclr/tools/Common/Compiler/Int128FieldLayoutAlgorithm.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -31,7 +31,7 @@ public override ComputedInstanceFieldLayout ComputeInstanceLayout(DefType defTyp
 ComputedInstanceFieldLayout layoutFromMetadata = _fallbackAlgorithm.ComputeInstanceLayout(defType, layoutKind);

 // 32bit platforms use standard metadata layout engine
 if (defType.Context.Target.Architecture == TargetArchitecture.ARM)
 if (defType.Context.Target.Architecture is TargetArchitecture.ARM or TargetArchitecture.Wasm32)
 {

Comment on lines

33
 to 
35

@lewinglewingJul 27, 2026

Copy link


Copy Markdown

MemberAuthor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Correct that the comment is imprecise — X86 is 32-bit and does take the 16-byte override. That imprecision predates this change though, and the condition it describes is right there on the next line, so I'd rather not expand it here: rewording a pre-existing comment is unrelated churn, and per repo convention comments are kept minimal because inaccurate ones mislead and need maintenance.
Happy to fix it if a maintainer would prefer.
Note
This comment was generated by GitHub Copilot.
 layoutFromMetadata.LayoutAbiStable = true;
 layoutFromMetadata.IsInt128OrHasInt128Fields = true;

Comment on lines

+34
 to 
37

@lewinglewingJul 27, 2026

Copy link


Copy Markdown

MemberAuthor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Added Wasm32 cases to TestAlignmentBehavior_AutoAlignmentRulesWithOSDependence in 5fe365d. Both fail without the layout change (alignment 16 rather than 8), so they actually guard the new branch rather than just documenting it.
Note
This comment was generated by GitHub Copilot.
Expand Down

13 changes: 13 additions & 0 deletions
src/coreclr/tools/aot/ILCompiler.TypeSystem.Tests/ArchitectureSpecificFieldLayoutTests.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -22,6 +22,8 @@ public class ArchitectureSpecificFieldLayoutTests
 private ModuleDesc _testModuleARM;
 private TestTypeSystemContext _contextARM64;
 private ModuleDesc _testModuleARM64;
 private TestTypeSystemContext _contextWasm32;
 private ModuleDesc _testModuleWasm32;

 public ArchitectureSpecificFieldLayoutTests()
 {
Expand DownExpand Up@@ -60,6 +62,12 @@ public ArchitectureSpecificFieldLayoutTests()
 _contextARM64.SetSystemModule(systemModuleARM64);

 _testModuleARM64 = systemModuleARM64;

 _contextWasm32 = new TestTypeSystemContext(TargetArchitecture.Wasm32);
 var systemModuleWasm32 = _contextWasm32.CreateModuleForSimpleName("CoreTestAssembly");
 _contextWasm32.SetSystemModule(systemModuleWasm32);

 _testModuleWasm32 = systemModuleWasm32;
 }

 [Fact]
Expand DownExpand Up@@ -501,11 +509,13 @@ public void TestAlignmentBehavior_AutoAlignmentRules(string wrapperType, int[] a
 [InlineData("StructStructByte_Int128StructAuto", "X86", 16, 32)]
 [InlineData("StructStructByte_Int128StructAuto", "X64Linux", 16, 32)]
 [InlineData("StructStructByte_Int128StructAuto", "X64Windows", 16, 32)]
 [InlineData("StructStructByte_Int128StructAuto", "Wasm32", 8, 24)]
 [InlineData("StructStructByte_UInt128StructAuto", "ARM64", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "ARM", 8, 24)]
 [InlineData("StructStructByte_UInt128StructAuto", "X86", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "X64Linux", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "X64Windows", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "Wasm32", 8, 24)]
 // Variation of TestAlignmentBehavior_AutoAlignmentRules above that is able to deal with os specific behavior
 public void TestAlignmentBehavior_AutoAlignmentRulesWithOSDependence(string wrapperType, string osArch, int alignment, int size)
 {
Expand All@@ -530,6 +540,9 @@ public void TestAlignmentBehavior_AutoAlignmentRulesWithOSDependence(string wrap
 case "X86":
 testModule = _testModuleX86;
 break;
 case "Wasm32":
 testModule = _testModuleWasm32;
 break;
 default:
 throw new Exception();
 }
Expand Down

3 changes: 2 additions & 1 deletion
src/coreclr/vm/methodtablebuilder.cpp

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -10817,7 +10817,8 @@ void MethodTableBuilder::CheckForSystemTypes()
 // even on X86
 pLayout->SetAlignmentRequirement(16); // sizeof(__int128)
#elif defined(TARGET_WASM)
 pLayout->SetAlignmentRequirement(16); // sizeof(v128)
 // Wasm has no 128-bit scalar type to match, so use the natural field alignment.
 pLayout->SetAlignmentRequirement(8);
#else
#error Unknown architecture
#endif // TARGET_64BIT

Comment on lines

+10820
 to 
10824

Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
[wasm] Use ordinary struct alignment for Int128/UInt128 on wasm#131421

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

 Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and
privacy statement. We’ll occasionally send you account related emails.

Already on GitHub?
Sign in
to your account

 Closed

lewing
wants to merge
2
commits into

from

 Closed


[wasm] Use ordinary struct alignment for Int128/UInt128 on wasm
#131421
Show file tree
Hide file tree
 Changes from all commits
Commits

Show all changes


2 commits


Select commit
Hold shift + click to select a range
6189b46

[wasm] Use ordinary struct alignment for Int128/UInt128 on wasm


lewing Jul 27, 2026
5fe365d

Add Wasm32 cases to the Int128/UInt128 architecture layout tests


lewing Jul 27, 2026

File filter

Filter by extension
Filter by extension
Conversations

Failed to load comments. 
Loading
Jump to

Jump to file


Failed to load files. 
Loading
 Diff view

 Diff view


2 changes: 1 addition & 1 deletion
src/coreclr/tools/Common/Compiler/Int128FieldLayoutAlgorithm.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -31,7 +31,7 @@ public override ComputedInstanceFieldLayout ComputeInstanceLayout(DefType defTyp
 ComputedInstanceFieldLayout layoutFromMetadata = _fallbackAlgorithm.ComputeInstanceLayout(defType, layoutKind);

 // 32bit platforms use standard metadata layout engine
 if (defType.Context.Target.Architecture == TargetArchitecture.ARM)
 if (defType.Context.Target.Architecture is TargetArchitecture.ARM or TargetArchitecture.Wasm32)
 {

Comment on lines

33
 to 
35

@lewinglewingJul 27, 2026

Copy link


Copy Markdown

MemberAuthor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Correct that the comment is imprecise — X86 is 32-bit and does take the 16-byte override. That imprecision predates this change though, and the condition it describes is right there on the next line, so I'd rather not expand it here: rewording a pre-existing comment is unrelated churn, and per repo convention comments are kept minimal because inaccurate ones mislead and need maintenance.
Happy to fix it if a maintainer would prefer.
Note
This comment was generated by GitHub Copilot.
 layoutFromMetadata.LayoutAbiStable = true;
 layoutFromMetadata.IsInt128OrHasInt128Fields = true;

Comment on lines

+34
 to 
37

@lewinglewingJul 27, 2026

Copy link


Copy Markdown

MemberAuthor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Added Wasm32 cases to TestAlignmentBehavior_AutoAlignmentRulesWithOSDependence in 5fe365d. Both fail without the layout change (alignment 16 rather than 8), so they actually guard the new branch rather than just documenting it.
Note
This comment was generated by GitHub Copilot.
Expand Down

13 changes: 13 additions & 0 deletions
src/coreclr/tools/aot/ILCompiler.TypeSystem.Tests/ArchitectureSpecificFieldLayoutTests.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -22,6 +22,8 @@ public class ArchitectureSpecificFieldLayoutTests
 private ModuleDesc _testModuleARM;
 private TestTypeSystemContext _contextARM64;
 private ModuleDesc _testModuleARM64;
 private TestTypeSystemContext _contextWasm32;
 private ModuleDesc _testModuleWasm32;

 public ArchitectureSpecificFieldLayoutTests()
 {
Expand DownExpand Up@@ -60,6 +62,12 @@ public ArchitectureSpecificFieldLayoutTests()
 _contextARM64.SetSystemModule(systemModuleARM64);

 _testModuleARM64 = systemModuleARM64;

 _contextWasm32 = new TestTypeSystemContext(TargetArchitecture.Wasm32);
 var systemModuleWasm32 = _contextWasm32.CreateModuleForSimpleName("CoreTestAssembly");
 _contextWasm32.SetSystemModule(systemModuleWasm32);

 _testModuleWasm32 = systemModuleWasm32;
 }

 [Fact]
Expand DownExpand Up@@ -501,11 +509,13 @@ public void TestAlignmentBehavior_AutoAlignmentRules(string wrapperType, int[] a
 [InlineData("StructStructByte_Int128StructAuto", "X86", 16, 32)]
 [InlineData("StructStructByte_Int128StructAuto", "X64Linux", 16, 32)]
 [InlineData("StructStructByte_Int128StructAuto", "X64Windows", 16, 32)]
 [InlineData("StructStructByte_Int128StructAuto", "Wasm32", 8, 24)]
 [InlineData("StructStructByte_UInt128StructAuto", "ARM64", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "ARM", 8, 24)]
 [InlineData("StructStructByte_UInt128StructAuto", "X86", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "X64Linux", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "X64Windows", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "Wasm32", 8, 24)]
 // Variation of TestAlignmentBehavior_AutoAlignmentRules above that is able to deal with os specific behavior
 public void TestAlignmentBehavior_AutoAlignmentRulesWithOSDependence(string wrapperType, string osArch, int alignment, int size)
 {
Expand All@@ -530,6 +540,9 @@ public void TestAlignmentBehavior_AutoAlignmentRulesWithOSDependence(string wrap
 case "X86":
 testModule = _testModuleX86;
 break;
 case "Wasm32":
 testModule = _testModuleWasm32;
 break;
 default:
 throw new Exception();
 }
Expand Down

3 changes: 2 additions & 1 deletion
src/coreclr/vm/methodtablebuilder.cpp

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -10817,7 +10817,8 @@ void MethodTableBuilder::CheckForSystemTypes()
 // even on X86
 pLayout->SetAlignmentRequirement(16); // sizeof(__int128)
#elif defined(TARGET_WASM)
 pLayout->SetAlignmentRequirement(16); // sizeof(v128)
 // Wasm has no 128-bit scalar type to match, so use the natural field alignment.
 pLayout->SetAlignmentRequirement(8);
#else
#error Unknown architecture
#endif // TARGET_64BIT

Comment on lines

+10820
 to 
10824

Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
[wasm] Use ordinary struct alignment for Int128/UInt128 on wasm#131421

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

 Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and
privacy statement. We’ll occasionally send you account related emails.

Already on GitHub?
Sign in
to your account

 Closed

lewing
wants to merge
2
commits into

from

 Closed


[wasm] Use ordinary struct alignment for Int128/UInt128 on wasm
#131421
Show file tree
Hide file tree
 Changes from all commits
Commits

Show all changes


2 commits


Select commit
Hold shift + click to select a range
6189b46

[wasm] Use ordinary struct alignment for Int128/UInt128 on wasm


lewing Jul 27, 2026
5fe365d

Add Wasm32 cases to the Int128/UInt128 architecture layout tests


lewing Jul 27, 2026

File filter

Filter by extension
Filter by extension
Conversations

Failed to load comments. 
Loading
Jump to

Jump to file


Failed to load files. 
Loading
 Diff view

 Diff view


2 changes: 1 addition & 1 deletion
src/coreclr/tools/Common/Compiler/Int128FieldLayoutAlgorithm.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -31,7 +31,7 @@ public override ComputedInstanceFieldLayout ComputeInstanceLayout(DefType defTyp
 ComputedInstanceFieldLayout layoutFromMetadata = _fallbackAlgorithm.ComputeInstanceLayout(defType, layoutKind);

 // 32bit platforms use standard metadata layout engine
 if (defType.Context.Target.Architecture == TargetArchitecture.ARM)
 if (defType.Context.Target.Architecture is TargetArchitecture.ARM or TargetArchitecture.Wasm32)
 {

Comment on lines

33
 to 
35

@lewinglewingJul 27, 2026

Copy link


Copy Markdown

MemberAuthor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Correct that the comment is imprecise — X86 is 32-bit and does take the 16-byte override. That imprecision predates this change though, and the condition it describes is right there on the next line, so I'd rather not expand it here: rewording a pre-existing comment is unrelated churn, and per repo convention comments are kept minimal because inaccurate ones mislead and need maintenance.
Happy to fix it if a maintainer would prefer.
Note
This comment was generated by GitHub Copilot.
 layoutFromMetadata.LayoutAbiStable = true;
 layoutFromMetadata.IsInt128OrHasInt128Fields = true;

Comment on lines

+34
 to 
37

@lewinglewingJul 27, 2026

Copy link


Copy Markdown

MemberAuthor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Added Wasm32 cases to TestAlignmentBehavior_AutoAlignmentRulesWithOSDependence in 5fe365d. Both fail without the layout change (alignment 16 rather than 8), so they actually guard the new branch rather than just documenting it.
Note
This comment was generated by GitHub Copilot.
Expand Down

13 changes: 13 additions & 0 deletions
src/coreclr/tools/aot/ILCompiler.TypeSystem.Tests/ArchitectureSpecificFieldLayoutTests.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -22,6 +22,8 @@ public class ArchitectureSpecificFieldLayoutTests
 private ModuleDesc _testModuleARM;
 private TestTypeSystemContext _contextARM64;
 private ModuleDesc _testModuleARM64;
 private TestTypeSystemContext _contextWasm32;
 private ModuleDesc _testModuleWasm32;

 public ArchitectureSpecificFieldLayoutTests()
 {
Expand DownExpand Up@@ -60,6 +62,12 @@ public ArchitectureSpecificFieldLayoutTests()
 _contextARM64.SetSystemModule(systemModuleARM64);

 _testModuleARM64 = systemModuleARM64;

 _contextWasm32 = new TestTypeSystemContext(TargetArchitecture.Wasm32);
 var systemModuleWasm32 = _contextWasm32.CreateModuleForSimpleName("CoreTestAssembly");
 _contextWasm32.SetSystemModule(systemModuleWasm32);

 _testModuleWasm32 = systemModuleWasm32;
 }

 [Fact]
Expand DownExpand Up@@ -501,11 +509,13 @@ public void TestAlignmentBehavior_AutoAlignmentRules(string wrapperType, int[] a
 [InlineData("StructStructByte_Int128StructAuto", "X86", 16, 32)]
 [InlineData("StructStructByte_Int128StructAuto", "X64Linux", 16, 32)]
 [InlineData("StructStructByte_Int128StructAuto", "X64Windows", 16, 32)]
 [InlineData("StructStructByte_Int128StructAuto", "Wasm32", 8, 24)]
 [InlineData("StructStructByte_UInt128StructAuto", "ARM64", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "ARM", 8, 24)]
 [InlineData("StructStructByte_UInt128StructAuto", "X86", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "X64Linux", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "X64Windows", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "Wasm32", 8, 24)]
 // Variation of TestAlignmentBehavior_AutoAlignmentRules above that is able to deal with os specific behavior
 public void TestAlignmentBehavior_AutoAlignmentRulesWithOSDependence(string wrapperType, string osArch, int alignment, int size)
 {
Expand All@@ -530,6 +540,9 @@ public void TestAlignmentBehavior_AutoAlignmentRulesWithOSDependence(string wrap
 case "X86":
 testModule = _testModuleX86;
 break;
 case "Wasm32":
 testModule = _testModuleWasm32;
 break;
 default:
 throw new Exception();
 }
Expand Down

3 changes: 2 additions & 1 deletion
src/coreclr/vm/methodtablebuilder.cpp

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -10817,7 +10817,8 @@ void MethodTableBuilder::CheckForSystemTypes()
 // even on X86
 pLayout->SetAlignmentRequirement(16); // sizeof(__int128)
#elif defined(TARGET_WASM)
 pLayout->SetAlignmentRequirement(16); // sizeof(v128)
 // Wasm has no 128-bit scalar type to match, so use the natural field alignment.
 pLayout->SetAlignmentRequirement(8);
#else
#error Unknown architecture
#endif // TARGET_64BIT

Comment on lines

+10820
 to 
10824

Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

Skip to content
[wasm] Use ordinary struct alignment for Int128/UInt128 on wasm#131421

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

 Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and
privacy statement. We’ll occasionally send you account related emails.

Already on GitHub?
Sign in
to your account

 Closed

lewing
wants to merge
2
commits into

from

 Closed


[wasm] Use ordinary struct alignment for Int128/UInt128 on wasm
#131421
Show file tree
Hide file tree
 Changes from all commits
Commits

Show all changes


2 commits


Select commit
Hold shift + click to select a range
6189b46

[wasm] Use ordinary struct alignment for Int128/UInt128 on wasm


lewing Jul 27, 2026
5fe365d

Add Wasm32 cases to the Int128/UInt128 architecture layout tests


lewing Jul 27, 2026

File filter

Filter by extension
Filter by extension
Conversations

Failed to load comments. 
Loading
Jump to

Jump to file


Failed to load files. 
Loading
 Diff view

 Diff view


2 changes: 1 addition & 1 deletion
src/coreclr/tools/Common/Compiler/Int128FieldLayoutAlgorithm.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -31,7 +31,7 @@ public override ComputedInstanceFieldLayout ComputeInstanceLayout(DefType defTyp
 ComputedInstanceFieldLayout layoutFromMetadata = _fallbackAlgorithm.ComputeInstanceLayout(defType, layoutKind);

 // 32bit platforms use standard metadata layout engine
 if (defType.Context.Target.Architecture == TargetArchitecture.ARM)
 if (defType.Context.Target.Architecture is TargetArchitecture.ARM or TargetArchitecture.Wasm32)
 {

Comment on lines

33
 to 
35

@lewinglewingJul 27, 2026

Copy link


Copy Markdown

MemberAuthor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Correct that the comment is imprecise — X86 is 32-bit and does take the 16-byte override. That imprecision predates this change though, and the condition it describes is right there on the next line, so I'd rather not expand it here: rewording a pre-existing comment is unrelated churn, and per repo convention comments are kept minimal because inaccurate ones mislead and need maintenance.
Happy to fix it if a maintainer would prefer.
Note
This comment was generated by GitHub Copilot.
 layoutFromMetadata.LayoutAbiStable = true;
 layoutFromMetadata.IsInt128OrHasInt128Fields = true;

Comment on lines

+34
 to 
37

@lewinglewingJul 27, 2026

Copy link


Copy Markdown

MemberAuthor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Added Wasm32 cases to TestAlignmentBehavior_AutoAlignmentRulesWithOSDependence in 5fe365d. Both fail without the layout change (alignment 16 rather than 8), so they actually guard the new branch rather than just documenting it.
Note
This comment was generated by GitHub Copilot.
Expand Down

13 changes: 13 additions & 0 deletions
src/coreclr/tools/aot/ILCompiler.TypeSystem.Tests/ArchitectureSpecificFieldLayoutTests.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -22,6 +22,8 @@ public class ArchitectureSpecificFieldLayoutTests
 private ModuleDesc _testModuleARM;
 private TestTypeSystemContext _contextARM64;
 private ModuleDesc _testModuleARM64;
 private TestTypeSystemContext _contextWasm32;
 private ModuleDesc _testModuleWasm32;

 public ArchitectureSpecificFieldLayoutTests()
 {
Expand DownExpand Up@@ -60,6 +62,12 @@ public ArchitectureSpecificFieldLayoutTests()
 _contextARM64.SetSystemModule(systemModuleARM64);

 _testModuleARM64 = systemModuleARM64;

 _contextWasm32 = new TestTypeSystemContext(TargetArchitecture.Wasm32);
 var systemModuleWasm32 = _contextWasm32.CreateModuleForSimpleName("CoreTestAssembly");
 _contextWasm32.SetSystemModule(systemModuleWasm32);

 _testModuleWasm32 = systemModuleWasm32;
 }

 [Fact]
Expand DownExpand Up@@ -501,11 +509,13 @@ public void TestAlignmentBehavior_AutoAlignmentRules(string wrapperType, int[] a
 [InlineData("StructStructByte_Int128StructAuto", "X86", 16, 32)]
 [InlineData("StructStructByte_Int128StructAuto", "X64Linux", 16, 32)]
 [InlineData("StructStructByte_Int128StructAuto", "X64Windows", 16, 32)]
 [InlineData("StructStructByte_Int128StructAuto", "Wasm32", 8, 24)]
 [InlineData("StructStructByte_UInt128StructAuto", "ARM64", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "ARM", 8, 24)]
 [InlineData("StructStructByte_UInt128StructAuto", "X86", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "X64Linux", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "X64Windows", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "Wasm32", 8, 24)]
 // Variation of TestAlignmentBehavior_AutoAlignmentRules above that is able to deal with os specific behavior
 public void TestAlignmentBehavior_AutoAlignmentRulesWithOSDependence(string wrapperType, string osArch, int alignment, int size)
 {
Expand All@@ -530,6 +540,9 @@ public void TestAlignmentBehavior_AutoAlignmentRulesWithOSDependence(string wrap
 case "X86":
 testModule = _testModuleX86;
 break;
 case "Wasm32":
 testModule = _testModuleWasm32;
 break;
 default:
 throw new Exception();
 }
Expand Down

3 changes: 2 additions & 1 deletion
src/coreclr/vm/methodtablebuilder.cpp

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -10817,7 +10817,8 @@ void MethodTableBuilder::CheckForSystemTypes()
 // even on X86
 pLayout->SetAlignmentRequirement(16); // sizeof(__int128)
#elif defined(TARGET_WASM)
 pLayout->SetAlignmentRequirement(16); // sizeof(v128)
 // Wasm has no 128-bit scalar type to match, so use the natural field alignment.
 pLayout->SetAlignmentRequirement(8);
#else
#error Unknown architecture
#endif // TARGET_64BIT

Comment on lines

+10820
 to 
10824

Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
[wasm] Use ordinary struct alignment for Int128/UInt128 on wasm#131421

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

 Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and
privacy statement. We’ll occasionally send you account related emails.

Already on GitHub?
Sign in
to your account

 Closed

lewing
wants to merge
2
commits into

from

 Closed


[wasm] Use ordinary struct alignment for Int128/UInt128 on wasm
#131421
Show file tree
Hide file tree
 Changes from all commits
Commits

Show all changes


2 commits


Select commit
Hold shift + click to select a range
6189b46

[wasm] Use ordinary struct alignment for Int128/UInt128 on wasm


lewing Jul 27, 2026
5fe365d

Add Wasm32 cases to the Int128/UInt128 architecture layout tests


lewing Jul 27, 2026

File filter

Filter by extension
Filter by extension
Conversations

Failed to load comments. 
Loading
Jump to

Jump to file


Failed to load files. 
Loading
 Diff view

 Diff view


2 changes: 1 addition & 1 deletion
src/coreclr/tools/Common/Compiler/Int128FieldLayoutAlgorithm.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -31,7 +31,7 @@ public override ComputedInstanceFieldLayout ComputeInstanceLayout(DefType defTyp
 ComputedInstanceFieldLayout layoutFromMetadata = _fallbackAlgorithm.ComputeInstanceLayout(defType, layoutKind);

 // 32bit platforms use standard metadata layout engine
 if (defType.Context.Target.Architecture == TargetArchitecture.ARM)
 if (defType.Context.Target.Architecture is TargetArchitecture.ARM or TargetArchitecture.Wasm32)
 {

Comment on lines

33
 to 
35

@lewinglewingJul 27, 2026

Copy link


Copy Markdown

MemberAuthor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Correct that the comment is imprecise — X86 is 32-bit and does take the 16-byte override. That imprecision predates this change though, and the condition it describes is right there on the next line, so I'd rather not expand it here: rewording a pre-existing comment is unrelated churn, and per repo convention comments are kept minimal because inaccurate ones mislead and need maintenance.
Happy to fix it if a maintainer would prefer.
Note
This comment was generated by GitHub Copilot.
 layoutFromMetadata.LayoutAbiStable = true;
 layoutFromMetadata.IsInt128OrHasInt128Fields = true;

Comment on lines

+34
 to 
37

@lewinglewingJul 27, 2026

Copy link


Copy Markdown

MemberAuthor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Added Wasm32 cases to TestAlignmentBehavior_AutoAlignmentRulesWithOSDependence in 5fe365d. Both fail without the layout change (alignment 16 rather than 8), so they actually guard the new branch rather than just documenting it.
Note
This comment was generated by GitHub Copilot.
Expand Down

13 changes: 13 additions & 0 deletions
src/coreclr/tools/aot/ILCompiler.TypeSystem.Tests/ArchitectureSpecificFieldLayoutTests.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -22,6 +22,8 @@ public class ArchitectureSpecificFieldLayoutTests
 private ModuleDesc _testModuleARM;
 private TestTypeSystemContext _contextARM64;
 private ModuleDesc _testModuleARM64;
 private TestTypeSystemContext _contextWasm32;
 private ModuleDesc _testModuleWasm32;

 public ArchitectureSpecificFieldLayoutTests()
 {
Expand DownExpand Up@@ -60,6 +62,12 @@ public ArchitectureSpecificFieldLayoutTests()
 _contextARM64.SetSystemModule(systemModuleARM64);

 _testModuleARM64 = systemModuleARM64;

 _contextWasm32 = new TestTypeSystemContext(TargetArchitecture.Wasm32);
 var systemModuleWasm32 = _contextWasm32.CreateModuleForSimpleName("CoreTestAssembly");
 _contextWasm32.SetSystemModule(systemModuleWasm32);

 _testModuleWasm32 = systemModuleWasm32;
 }

 [Fact]
Expand DownExpand Up@@ -501,11 +509,13 @@ public void TestAlignmentBehavior_AutoAlignmentRules(string wrapperType, int[] a
 [InlineData("StructStructByte_Int128StructAuto", "X86", 16, 32)]
 [InlineData("StructStructByte_Int128StructAuto", "X64Linux", 16, 32)]
 [InlineData("StructStructByte_Int128StructAuto", "X64Windows", 16, 32)]
 [InlineData("StructStructByte_Int128StructAuto", "Wasm32", 8, 24)]
 [InlineData("StructStructByte_UInt128StructAuto", "ARM64", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "ARM", 8, 24)]
 [InlineData("StructStructByte_UInt128StructAuto", "X86", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "X64Linux", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "X64Windows", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "Wasm32", 8, 24)]
 // Variation of TestAlignmentBehavior_AutoAlignmentRules above that is able to deal with os specific behavior
 public void TestAlignmentBehavior_AutoAlignmentRulesWithOSDependence(string wrapperType, string osArch, int alignment, int size)
 {
Expand All@@ -530,6 +540,9 @@ public void TestAlignmentBehavior_AutoAlignmentRulesWithOSDependence(string wrap
 case "X86":
 testModule = _testModuleX86;
 break;
 case "Wasm32":
 testModule = _testModuleWasm32;
 break;
 default:
 throw new Exception();
 }
Expand Down

3 changes: 2 additions & 1 deletion
src/coreclr/vm/methodtablebuilder.cpp

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -10817,7 +10817,8 @@ void MethodTableBuilder::CheckForSystemTypes()
 // even on X86
 pLayout->SetAlignmentRequirement(16); // sizeof(__int128)
#elif defined(TARGET_WASM)
 pLayout->SetAlignmentRequirement(16); // sizeof(v128)
 // Wasm has no 128-bit scalar type to match, so use the natural field alignment.
 pLayout->SetAlignmentRequirement(8);
#else
#error Unknown architecture
#endif // TARGET_64BIT

Comment on lines

+10820
 to 
10824

Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
[wasm] Use ordinary struct alignment for Int128/UInt128 on wasm#131421

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

 Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and
privacy statement. We’ll occasionally send you account related emails.

Already on GitHub?
Sign in
to your account

 Closed

lewing
wants to merge
2
commits into

from

 Closed


[wasm] Use ordinary struct alignment for Int128/UInt128 on wasm
#131421
Show file tree
Hide file tree
 Changes from all commits
Commits

Show all changes


2 commits


Select commit
Hold shift + click to select a range
6189b46

[wasm] Use ordinary struct alignment for Int128/UInt128 on wasm


lewing Jul 27, 2026
5fe365d

Add Wasm32 cases to the Int128/UInt128 architecture layout tests


lewing Jul 27, 2026

File filter

Filter by extension
Filter by extension
Conversations

Failed to load comments. 
Loading
Jump to

Jump to file


Failed to load files. 
Loading
 Diff view

 Diff view


2 changes: 1 addition & 1 deletion
src/coreclr/tools/Common/Compiler/Int128FieldLayoutAlgorithm.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -31,7 +31,7 @@ public override ComputedInstanceFieldLayout ComputeInstanceLayout(DefType defTyp
 ComputedInstanceFieldLayout layoutFromMetadata = _fallbackAlgorithm.ComputeInstanceLayout(defType, layoutKind);

 // 32bit platforms use standard metadata layout engine
 if (defType.Context.Target.Architecture == TargetArchitecture.ARM)
 if (defType.Context.Target.Architecture is TargetArchitecture.ARM or TargetArchitecture.Wasm32)
 {

Comment on lines

33
 to 
35

@lewinglewingJul 27, 2026

Copy link


Copy Markdown

MemberAuthor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Correct that the comment is imprecise — X86 is 32-bit and does take the 16-byte override. That imprecision predates this change though, and the condition it describes is right there on the next line, so I'd rather not expand it here: rewording a pre-existing comment is unrelated churn, and per repo convention comments are kept minimal because inaccurate ones mislead and need maintenance.
Happy to fix it if a maintainer would prefer.
Note
This comment was generated by GitHub Copilot.
 layoutFromMetadata.LayoutAbiStable = true;
 layoutFromMetadata.IsInt128OrHasInt128Fields = true;

Comment on lines

+34
 to 
37

@lewinglewingJul 27, 2026

Copy link


Copy Markdown

MemberAuthor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Added Wasm32 cases to TestAlignmentBehavior_AutoAlignmentRulesWithOSDependence in 5fe365d. Both fail without the layout change (alignment 16 rather than 8), so they actually guard the new branch rather than just documenting it.
Note
This comment was generated by GitHub Copilot.
Expand Down

13 changes: 13 additions & 0 deletions
src/coreclr/tools/aot/ILCompiler.TypeSystem.Tests/ArchitectureSpecificFieldLayoutTests.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -22,6 +22,8 @@ public class ArchitectureSpecificFieldLayoutTests
 private ModuleDesc _testModuleARM;
 private TestTypeSystemContext _contextARM64;
 private ModuleDesc _testModuleARM64;
 private TestTypeSystemContext _contextWasm32;
 private ModuleDesc _testModuleWasm32;

 public ArchitectureSpecificFieldLayoutTests()
 {
Expand DownExpand Up@@ -60,6 +62,12 @@ public ArchitectureSpecificFieldLayoutTests()
 _contextARM64.SetSystemModule(systemModuleARM64);

 _testModuleARM64 = systemModuleARM64;

 _contextWasm32 = new TestTypeSystemContext(TargetArchitecture.Wasm32);
 var systemModuleWasm32 = _contextWasm32.CreateModuleForSimpleName("CoreTestAssembly");
 _contextWasm32.SetSystemModule(systemModuleWasm32);

 _testModuleWasm32 = systemModuleWasm32;
 }

 [Fact]
Expand DownExpand Up@@ -501,11 +509,13 @@ public void TestAlignmentBehavior_AutoAlignmentRules(string wrapperType, int[] a
 [InlineData("StructStructByte_Int128StructAuto", "X86", 16, 32)]
 [InlineData("StructStructByte_Int128StructAuto", "X64Linux", 16, 32)]
 [InlineData("StructStructByte_Int128StructAuto", "X64Windows", 16, 32)]
 [InlineData("StructStructByte_Int128StructAuto", "Wasm32", 8, 24)]
 [InlineData("StructStructByte_UInt128StructAuto", "ARM64", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "ARM", 8, 24)]
 [InlineData("StructStructByte_UInt128StructAuto", "X86", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "X64Linux", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "X64Windows", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "Wasm32", 8, 24)]
 // Variation of TestAlignmentBehavior_AutoAlignmentRules above that is able to deal with os specific behavior
 public void TestAlignmentBehavior_AutoAlignmentRulesWithOSDependence(string wrapperType, string osArch, int alignment, int size)
 {
Expand All@@ -530,6 +540,9 @@ public void TestAlignmentBehavior_AutoAlignmentRulesWithOSDependence(string wrap
 case "X86":
 testModule = _testModuleX86;
 break;
 case "Wasm32":
 testModule = _testModuleWasm32;
 break;
 default:
 throw new Exception();
 }
Expand Down

3 changes: 2 additions & 1 deletion
src/coreclr/vm/methodtablebuilder.cpp

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -10817,7 +10817,8 @@ void MethodTableBuilder::CheckForSystemTypes()
 // even on X86
 pLayout->SetAlignmentRequirement(16); // sizeof(__int128)
#elif defined(TARGET_WASM)
 pLayout->SetAlignmentRequirement(16); // sizeof(v128)
 // Wasm has no 128-bit scalar type to match, so use the natural field alignment.
 pLayout->SetAlignmentRequirement(8);
#else
#error Unknown architecture
#endif // TARGET_64BIT

Comment on lines

+10820
 to 
10824

Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

Skip to content
[wasm] Use ordinary struct alignment for Int128/UInt128 on wasm#131421

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

 Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and
privacy statement. We’ll occasionally send you account related emails.

Already on GitHub?
Sign in
to your account

 Closed

lewing
wants to merge
2
commits into

from

 Closed


[wasm] Use ordinary struct alignment for Int128/UInt128 on wasm
#131421
Show file tree
Hide file tree
 Changes from all commits
Commits

Show all changes


2 commits


Select commit
Hold shift + click to select a range
6189b46

[wasm] Use ordinary struct alignment for Int128/UInt128 on wasm


lewing Jul 27, 2026
5fe365d

Add Wasm32 cases to the Int128/UInt128 architecture layout tests


lewing Jul 27, 2026

File filter

Filter by extension
Filter by extension
Conversations

Failed to load comments. 
Loading
Jump to

Jump to file


Failed to load files. 
Loading
 Diff view

 Diff view


2 changes: 1 addition & 1 deletion
src/coreclr/tools/Common/Compiler/Int128FieldLayoutAlgorithm.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -31,7 +31,7 @@ public override ComputedInstanceFieldLayout ComputeInstanceLayout(DefType defTyp
 ComputedInstanceFieldLayout layoutFromMetadata = _fallbackAlgorithm.ComputeInstanceLayout(defType, layoutKind);

 // 32bit platforms use standard metadata layout engine
 if (defType.Context.Target.Architecture == TargetArchitecture.ARM)
 if (defType.Context.Target.Architecture is TargetArchitecture.ARM or TargetArchitecture.Wasm32)
 {

Comment on lines

33
 to 
35

@lewinglewingJul 27, 2026

Copy link


Copy Markdown

MemberAuthor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Correct that the comment is imprecise — X86 is 32-bit and does take the 16-byte override. That imprecision predates this change though, and the condition it describes is right there on the next line, so I'd rather not expand it here: rewording a pre-existing comment is unrelated churn, and per repo convention comments are kept minimal because inaccurate ones mislead and need maintenance.
Happy to fix it if a maintainer would prefer.
Note
This comment was generated by GitHub Copilot.
 layoutFromMetadata.LayoutAbiStable = true;
 layoutFromMetadata.IsInt128OrHasInt128Fields = true;

Comment on lines

+34
 to 
37

@lewinglewingJul 27, 2026

Copy link


Copy Markdown

MemberAuthor
Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Added Wasm32 cases to TestAlignmentBehavior_AutoAlignmentRulesWithOSDependence in 5fe365d. Both fail without the layout change (alignment 16 rather than 8), so they actually guard the new branch rather than just documenting it.
Note
This comment was generated by GitHub Copilot.
Expand Down

13 changes: 13 additions & 0 deletions
src/coreclr/tools/aot/ILCompiler.TypeSystem.Tests/ArchitectureSpecificFieldLayoutTests.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -22,6 +22,8 @@ public class ArchitectureSpecificFieldLayoutTests
 private ModuleDesc _testModuleARM;
 private TestTypeSystemContext _contextARM64;
 private ModuleDesc _testModuleARM64;
 private TestTypeSystemContext _contextWasm32;
 private ModuleDesc _testModuleWasm32;

 public ArchitectureSpecificFieldLayoutTests()
 {
Expand DownExpand Up@@ -60,6 +62,12 @@ public ArchitectureSpecificFieldLayoutTests()
 _contextARM64.SetSystemModule(systemModuleARM64);

 _testModuleARM64 = systemModuleARM64;

 _contextWasm32 = new TestTypeSystemContext(TargetArchitecture.Wasm32);
 var systemModuleWasm32 = _contextWasm32.CreateModuleForSimpleName("CoreTestAssembly");
 _contextWasm32.SetSystemModule(systemModuleWasm32);

 _testModuleWasm32 = systemModuleWasm32;
 }

 [Fact]
Expand DownExpand Up@@ -501,11 +509,13 @@ public void TestAlignmentBehavior_AutoAlignmentRules(string wrapperType, int[] a
 [InlineData("StructStructByte_Int128StructAuto", "X86", 16, 32)]
 [InlineData("StructStructByte_Int128StructAuto", "X64Linux", 16, 32)]
 [InlineData("StructStructByte_Int128StructAuto", "X64Windows", 16, 32)]
 [InlineData("StructStructByte_Int128StructAuto", "Wasm32", 8, 24)]
 [InlineData("StructStructByte_UInt128StructAuto", "ARM64", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "ARM", 8, 24)]
 [InlineData("StructStructByte_UInt128StructAuto", "X86", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "X64Linux", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "X64Windows", 16, 32)]
 [InlineData("StructStructByte_UInt128StructAuto", "Wasm32", 8, 24)]
 // Variation of TestAlignmentBehavior_AutoAlignmentRules above that is able to deal with os specific behavior
 public void TestAlignmentBehavior_AutoAlignmentRulesWithOSDependence(string wrapperType, string osArch, int alignment, int size)
 {
Expand All@@ -530,6 +540,9 @@ public void TestAlignmentBehavior_AutoAlignmentRulesWithOSDependence(string wrap
 case "X86":
 testModule = _testModuleX86;
 break;
 case "Wasm32":
 testModule = _testModuleWasm32;
 break;
 default:
 throw new Exception();
 }
Expand Down

3 changes: 2 additions & 1 deletion
src/coreclr/vm/methodtablebuilder.cpp

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -10817,7 +10817,8 @@ void MethodTableBuilder::CheckForSystemTypes()
 // even on X86
 pLayout->SetAlignmentRequirement(16); // sizeof(__int128)
#elif defined(TARGET_WASM)
 pLayout->SetAlignmentRequirement(16); // sizeof(v128)
 // Wasm has no 128-bit scalar type to match, so use the natural field alignment.
 pLayout->SetAlignmentRequirement(8);
#else
#error Unknown architecture
#endif // TARGET_64BIT

Comment on lines

+10820
 to 
10824

Expand Down
Loading