Switch NameMangler to UTF-8 - #122128

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MichalStrehovsky merged 2 commits into
dotnet:mainfrom
MichalStrehovsky:uf8mangler
Dec 3, 2025
Merged

Switch NameMangler to UTF-8#122128
MichalStrehovsky merged 2 commits into
dotnet:mainfrom
MichalStrehovsky:uf8mangler

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@MichalStrehovskyMichalStrehovsky commented Dec 2, 2025

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Removes some unnecessary UTF-8 -> UTF-16 -> UTF-8 conversions.

Before this change, when compiling hello world: 529000 byte[] allocations, 403000 string allocations.
After this change: 552000 byte[] allocations, 302000 string allocations.

Cc @dotnet/ilc-contrib

CopilotAI review requested due to automatic review settings December 2, 2025 23:05
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Pull request overview

This PR optimizes the ILCompiler by switching the NameMangler from UTF-16 strings to UTF-8, eliminating unnecessary encoding conversions during compilation. The change reduces string allocations by approximately 101,000 instances when compiling a hello world application (from 403,000 to 302,000), though it increases byte array allocations slightly (from 529,000 to 552,000).

Key Changes:

  • Modified NameMangler.GetMangledTypeName() and related methods to return Utf8String instead of string
  • Implemented UTF-8 versions of name sanitization and disambiguation logic
  • Added UTF-8 string writing overloads in debug info builders and section writers

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 6 comments.

Show a summary per file
FileDescription
src/coreclr/tools/Common/Compiler/NameMangler.csChanged abstract method signatures from string to Utf8String for type and name mangling
src/coreclr/tools/Common/Compiler/NativeAotNameMangler.csImplemented UTF-8 versions of name mangling, sanitization, and disambiguation logic; added CountDigits helper for efficient numeric formatting
src/coreclr/tools/Common/Internal/Text/Utf8String.csAdded Concat method to combine multiple UTF-8 strings without conversion
src/coreclr/tools/Common/Internal/Text/Utf8StringBuilder.csAdded constructor accepting initial capacity parameter
src/coreclr/tools/Common/Compiler/ObjectWriter/SectionWriter.csAdded WriteUtf8String(Utf8String) overload to write UTF-8 strings directly
src/coreclr/tools/Common/TypeSystem/TypesDebugInfoWriter/TypesDebugInfoWriter.csChanged interface methods and type descriptors to use Utf8String
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/Dwarf/DwarfInfoWriter.csAdded WriteStringReference(Utf8String) overload for UTF-8 string references
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/Dwarf/DwarfBuilder.csChanged GetMangledName to return Utf8String
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewTypesBuilder.csUpdated user-defined types to use Utf8String; added Write(Utf8String) overload
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewSymbolsBuilder.csUpdated WriteUserDefinedTypes signature and added Write(Utf8String) overload
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/WindowsNodeMangler.csAdded ToString() call to convert UTF-8 result to string for method table names
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/UnixNodeMangler.csAdded ToString() call to convert UTF-8 result to string for method table names

Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment thread...coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewTypesBuilder.cs
Comment thread...reclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewSymbolsBuilder.cs
am11
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Comment threadsrc/coreclr/tools/Common/Internal/Text/Utf8String.cs
This was referenced Dec 3, 2025
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Nice! Do we have any unit tests for the name mangler? If not I could have copilot give it a shot

Comment threadsrc/coreclr/tools/aot/ILCompiler.Compiler/Compiler/UnixNodeMangler.cs Outdated
Comment threadsrc/coreclr/tools/aot/ILCompiler.Compiler/Compiler/WindowsNodeMangler.cs Outdated
@MichalStrehovsky

MichalStrehovsky commented Dec 3, 2025•
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Nice! Do we have any unit tests for the name mangler? If not I could have copilot give it a shot

I validated this by comparing the output object file (it was byte identical). We don't have unit tests; we can try giving it a shot if copilot comes up with something useful. But name mangling is typically not touched so I can only see the unit test getting in the way if we ever change how we want to mangle things (it is an implementation detail and not a contract). A unit test would definitely make this PR more annoying to do.

@build-analysisbuild-analysisBot mentioned this pull request Dec 3, 2025
Closed
@MichalStrehovsky
MichalStrehovsky merged commit f7a3ad3 into dotnet:mainDec 3, 2025
92 of 96 checks passed
@MichalStrehovsky
MichalStrehovsky deleted the uf8mangler branch December 3, 2025 13:16
@dotnet-maestrodotnet-maestroBot mentioned this pull request Dec 4, 2025
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, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all \u003cpre\u003e\u003ccode\u003e 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" + '
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Switch NameMangler to UTF-8 - #122128

Merged
MichalStrehovsky merged 2 commits into
dotnet:mainfrom
MichalStrehovsky:uf8mangler
Dec 3, 2025
Merged

Switch NameMangler to UTF-8#122128
MichalStrehovsky merged 2 commits into
dotnet:mainfrom
MichalStrehovsky:uf8mangler

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@MichalStrehovsky

@MichalStrehovskyMichalStrehovsky commented Dec 2, 2025

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Removes some unnecessary UTF-8 -> UTF-16 -> UTF-8 conversions.

Before this change, when compiling hello world: 529000 byte[] allocations, 403000 string allocations.
After this change: 552000 byte[] allocations, 302000 string allocations.

Cc @dotnet/ilc-contrib

CopilotAI review requested due to automatic review settings December 2, 2025 23:05
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Pull request overview

This PR optimizes the ILCompiler by switching the NameMangler from UTF-16 strings to UTF-8, eliminating unnecessary encoding conversions during compilation. The change reduces string allocations by approximately 101,000 instances when compiling a hello world application (from 403,000 to 302,000), though it increases byte array allocations slightly (from 529,000 to 552,000).

Key Changes:

  • Modified NameMangler.GetMangledTypeName() and related methods to return Utf8String instead of string
  • Implemented UTF-8 versions of name sanitization and disambiguation logic
  • Added UTF-8 string writing overloads in debug info builders and section writers

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 6 comments.

Show a summary per file
FileDescription
src/coreclr/tools/Common/Compiler/NameMangler.csChanged abstract method signatures from string to Utf8String for type and name mangling
src/coreclr/tools/Common/Compiler/NativeAotNameMangler.csImplemented UTF-8 versions of name mangling, sanitization, and disambiguation logic; added CountDigits helper for efficient numeric formatting
src/coreclr/tools/Common/Internal/Text/Utf8String.csAdded Concat method to combine multiple UTF-8 strings without conversion
src/coreclr/tools/Common/Internal/Text/Utf8StringBuilder.csAdded constructor accepting initial capacity parameter
src/coreclr/tools/Common/Compiler/ObjectWriter/SectionWriter.csAdded WriteUtf8String(Utf8String) overload to write UTF-8 strings directly
src/coreclr/tools/Common/TypeSystem/TypesDebugInfoWriter/TypesDebugInfoWriter.csChanged interface methods and type descriptors to use Utf8String
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/Dwarf/DwarfInfoWriter.csAdded WriteStringReference(Utf8String) overload for UTF-8 string references
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/Dwarf/DwarfBuilder.csChanged GetMangledName to return Utf8String
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewTypesBuilder.csUpdated user-defined types to use Utf8String; added Write(Utf8String) overload
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewSymbolsBuilder.csUpdated WriteUserDefinedTypes signature and added Write(Utf8String) overload
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/WindowsNodeMangler.csAdded ToString() call to convert UTF-8 result to string for method table names
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/UnixNodeMangler.csAdded ToString() call to convert UTF-8 result to string for method table names

Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment thread...coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewTypesBuilder.cs
Comment thread...reclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewSymbolsBuilder.cs
am11
am11 reviewed Dec 3, 2025
View reviewed changes
Comment threadsrc/coreclr/tools/Common/Internal/Text/Utf8String.cs
This was referenced Dec 3, 2025
Open
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agocke
agocke approved these changes Dec 3, 2025
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Nice! Do we have any unit tests for the name mangler? If not I could have copilot give it a shot

Comment threadsrc/coreclr/tools/aot/ILCompiler.Compiler/Compiler/UnixNodeMangler.cs Outdated
Comment threadsrc/coreclr/tools/aot/ILCompiler.Compiler/Compiler/WindowsNodeMangler.cs Outdated
@MichalStrehovsky

MichalStrehovsky commented Dec 3, 2025•
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Nice! Do we have any unit tests for the name mangler? If not I could have copilot give it a shot

I validated this by comparing the output object file (it was byte identical). We don't have unit tests; we can try giving it a shot if copilot comes up with something useful. But name mangling is typically not touched so I can only see the unit test getting in the way if we ever change how we want to mangle things (it is an implementation detail and not a contract). A unit test would definitely make this PR more annoying to do.

@build-analysisbuild-analysisBot mentioned this pull request Dec 3, 2025
Closed
@MichalStrehovsky
MichalStrehovsky merged commit f7a3ad3 into dotnet:mainDec 3, 2025
92 of 96 checks passed
@MichalStrehovsky
MichalStrehovsky deleted the uf8mangler branch December 3, 2025 13:16
@dotnet-maestrodotnet-maestroBot mentioned this pull request Dec 4, 2025
Merged
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@agockeagockeagocke approved these changes
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, '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('^' + ".*" + '
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Switch NameMangler to UTF-8 - #122128

Merged
MichalStrehovsky merged 2 commits into
dotnet:mainfrom
MichalStrehovsky:uf8mangler
Dec 3, 2025
Merged

Switch NameMangler to UTF-8#122128
MichalStrehovsky merged 2 commits into
dotnet:mainfrom
MichalStrehovsky:uf8mangler

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@MichalStrehovsky

@MichalStrehovskyMichalStrehovsky commented Dec 2, 2025

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Removes some unnecessary UTF-8 -> UTF-16 -> UTF-8 conversions.

Before this change, when compiling hello world: 529000 byte[] allocations, 403000 string allocations.
After this change: 552000 byte[] allocations, 302000 string allocations.

Cc @dotnet/ilc-contrib

CopilotAI review requested due to automatic review settings December 2, 2025 23:05
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Tagging subscribers to this area: @agocke, @MichalStrehovsky, @jkotas
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Pull request overview

This PR optimizes the ILCompiler by switching the NameMangler from UTF-16 strings to UTF-8, eliminating unnecessary encoding conversions during compilation. The change reduces string allocations by approximately 101,000 instances when compiling a hello world application (from 403,000 to 302,000), though it increases byte array allocations slightly (from 529,000 to 552,000).

Key Changes:

  • Modified NameMangler.GetMangledTypeName() and related methods to return Utf8String instead of string
  • Implemented UTF-8 versions of name sanitization and disambiguation logic
  • Added UTF-8 string writing overloads in debug info builders and section writers

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 6 comments.

Show a summary per file
FileDescription
src/coreclr/tools/Common/Compiler/NameMangler.csChanged abstract method signatures from string to Utf8String for type and name mangling
src/coreclr/tools/Common/Compiler/NativeAotNameMangler.csImplemented UTF-8 versions of name mangling, sanitization, and disambiguation logic; added CountDigits helper for efficient numeric formatting
src/coreclr/tools/Common/Internal/Text/Utf8String.csAdded Concat method to combine multiple UTF-8 strings without conversion
src/coreclr/tools/Common/Internal/Text/Utf8StringBuilder.csAdded constructor accepting initial capacity parameter
src/coreclr/tools/Common/Compiler/ObjectWriter/SectionWriter.csAdded WriteUtf8String(Utf8String) overload to write UTF-8 strings directly
src/coreclr/tools/Common/TypeSystem/TypesDebugInfoWriter/TypesDebugInfoWriter.csChanged interface methods and type descriptors to use Utf8String
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/Dwarf/DwarfInfoWriter.csAdded WriteStringReference(Utf8String) overload for UTF-8 string references
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/Dwarf/DwarfBuilder.csChanged GetMangledName to return Utf8String
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewTypesBuilder.csUpdated user-defined types to use Utf8String; added Write(Utf8String) overload
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewSymbolsBuilder.csUpdated WriteUserDefinedTypes signature and added Write(Utf8String) overload
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/WindowsNodeMangler.csAdded ToString() call to convert UTF-8 result to string for method table names
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/UnixNodeMangler.csAdded ToString() call to convert UTF-8 result to string for method table names

Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment thread...coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewTypesBuilder.cs
Comment thread...reclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewSymbolsBuilder.cs
am11
am11 reviewed Dec 3, 2025
View reviewed changes
Comment threadsrc/coreclr/tools/Common/Internal/Text/Utf8String.cs
This was referenced Dec 3, 2025
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agocke
agocke approved these changes Dec 3, 2025
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Nice! Do we have any unit tests for the name mangler? If not I could have copilot give it a shot

Comment threadsrc/coreclr/tools/aot/ILCompiler.Compiler/Compiler/UnixNodeMangler.cs Outdated
Comment threadsrc/coreclr/tools/aot/ILCompiler.Compiler/Compiler/WindowsNodeMangler.cs Outdated
@MichalStrehovsky

MichalStrehovsky commented Dec 3, 2025•
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Nice! Do we have any unit tests for the name mangler? If not I could have copilot give it a shot

I validated this by comparing the output object file (it was byte identical). We don't have unit tests; we can try giving it a shot if copilot comes up with something useful. But name mangling is typically not touched so I can only see the unit test getting in the way if we ever change how we want to mangle things (it is an implementation detail and not a contract). A unit test would definitely make this PR more annoying to do.

@build-analysisbuild-analysisBot mentioned this pull request Dec 3, 2025
Closed
@MichalStrehovsky
MichalStrehovsky merged commit f7a3ad3 into dotnet:mainDec 3, 2025
92 of 96 checks passed
@MichalStrehovsky
MichalStrehovsky deleted the uf8mangler branch December 3, 2025 13:16
@dotnet-maestrodotnet-maestroBot mentioned this pull request Dec 4, 2025
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, '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 \u003e 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('^' + ".*" + '
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Switch NameMangler to UTF-8 - #122128

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MichalStrehovsky merged 2 commits into
dotnet:mainfrom
MichalStrehovsky:uf8mangler
Dec 3, 2025
Merged

Switch NameMangler to UTF-8#122128
MichalStrehovsky merged 2 commits into
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MichalStrehovsky:uf8mangler

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@MichalStrehovskyMichalStrehovsky commented Dec 2, 2025

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Removes some unnecessary UTF-8 -> UTF-16 -> UTF-8 conversions.

Before this change, when compiling hello world: 529000 byte[] allocations, 403000 string allocations.
After this change: 552000 byte[] allocations, 302000 string allocations.

Cc @dotnet/ilc-contrib

CopilotAI review requested due to automatic review settings December 2, 2025 23:05
@dotnet-policy-service

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Tagging subscribers to this area: @agocke, @MichalStrehovsky, @jkotas
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Pull request overview

This PR optimizes the ILCompiler by switching the NameMangler from UTF-16 strings to UTF-8, eliminating unnecessary encoding conversions during compilation. The change reduces string allocations by approximately 101,000 instances when compiling a hello world application (from 403,000 to 302,000), though it increases byte array allocations slightly (from 529,000 to 552,000).

Key Changes:

  • Modified NameMangler.GetMangledTypeName() and related methods to return Utf8String instead of string
  • Implemented UTF-8 versions of name sanitization and disambiguation logic
  • Added UTF-8 string writing overloads in debug info builders and section writers

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 6 comments.

Show a summary per file
FileDescription
src/coreclr/tools/Common/Compiler/NameMangler.csChanged abstract method signatures from string to Utf8String for type and name mangling
src/coreclr/tools/Common/Compiler/NativeAotNameMangler.csImplemented UTF-8 versions of name mangling, sanitization, and disambiguation logic; added CountDigits helper for efficient numeric formatting
src/coreclr/tools/Common/Internal/Text/Utf8String.csAdded Concat method to combine multiple UTF-8 strings without conversion
src/coreclr/tools/Common/Internal/Text/Utf8StringBuilder.csAdded constructor accepting initial capacity parameter
src/coreclr/tools/Common/Compiler/ObjectWriter/SectionWriter.csAdded WriteUtf8String(Utf8String) overload to write UTF-8 strings directly
src/coreclr/tools/Common/TypeSystem/TypesDebugInfoWriter/TypesDebugInfoWriter.csChanged interface methods and type descriptors to use Utf8String
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/Dwarf/DwarfInfoWriter.csAdded WriteStringReference(Utf8String) overload for UTF-8 string references
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/Dwarf/DwarfBuilder.csChanged GetMangledName to return Utf8String
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewTypesBuilder.csUpdated user-defined types to use Utf8String; added Write(Utf8String) overload
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewSymbolsBuilder.csUpdated WriteUserDefinedTypes signature and added Write(Utf8String) overload
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/WindowsNodeMangler.csAdded ToString() call to convert UTF-8 result to string for method table names
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/UnixNodeMangler.csAdded ToString() call to convert UTF-8 result to string for method table names

Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment thread...coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewTypesBuilder.cs
Comment thread...reclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewSymbolsBuilder.cs
am11
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Comment threadsrc/coreclr/tools/Common/Internal/Text/Utf8String.cs
This was referenced Dec 3, 2025
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Nice! Do we have any unit tests for the name mangler? If not I could have copilot give it a shot

Comment threadsrc/coreclr/tools/aot/ILCompiler.Compiler/Compiler/UnixNodeMangler.cs Outdated
Comment threadsrc/coreclr/tools/aot/ILCompiler.Compiler/Compiler/WindowsNodeMangler.cs Outdated
@MichalStrehovsky

MichalStrehovsky commented Dec 3, 2025•
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Nice! Do we have any unit tests for the name mangler? If not I could have copilot give it a shot

I validated this by comparing the output object file (it was byte identical). We don't have unit tests; we can try giving it a shot if copilot comes up with something useful. But name mangling is typically not touched so I can only see the unit test getting in the way if we ever change how we want to mangle things (it is an implementation detail and not a contract). A unit test would definitely make this PR more annoying to do.

@build-analysisbuild-analysisBot mentioned this pull request Dec 3, 2025
Closed
@MichalStrehovsky
MichalStrehovsky merged commit f7a3ad3 into dotnet:mainDec 3, 2025
92 of 96 checks passed
@MichalStrehovsky
MichalStrehovsky deleted the uf8mangler branch December 3, 2025 13:16
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, '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" + '
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Switch NameMangler to UTF-8 - #122128

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MichalStrehovsky merged 2 commits into
dotnet:mainfrom
MichalStrehovsky:uf8mangler
Dec 3, 2025
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Switch NameMangler to UTF-8#122128
MichalStrehovsky merged 2 commits into
dotnet:mainfrom
MichalStrehovsky:uf8mangler

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@MichalStrehovskyMichalStrehovsky commented Dec 2, 2025

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Removes some unnecessary UTF-8 -> UTF-16 -> UTF-8 conversions.

Before this change, when compiling hello world: 529000 byte[] allocations, 403000 string allocations.
After this change: 552000 byte[] allocations, 302000 string allocations.

Cc @dotnet/ilc-contrib

CopilotAI review requested due to automatic review settings December 2, 2025 23:05
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Pull request overview

This PR optimizes the ILCompiler by switching the NameMangler from UTF-16 strings to UTF-8, eliminating unnecessary encoding conversions during compilation. The change reduces string allocations by approximately 101,000 instances when compiling a hello world application (from 403,000 to 302,000), though it increases byte array allocations slightly (from 529,000 to 552,000).

Key Changes:

  • Modified NameMangler.GetMangledTypeName() and related methods to return Utf8String instead of string
  • Implemented UTF-8 versions of name sanitization and disambiguation logic
  • Added UTF-8 string writing overloads in debug info builders and section writers

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 6 comments.

Show a summary per file
FileDescription
src/coreclr/tools/Common/Compiler/NameMangler.csChanged abstract method signatures from string to Utf8String for type and name mangling
src/coreclr/tools/Common/Compiler/NativeAotNameMangler.csImplemented UTF-8 versions of name mangling, sanitization, and disambiguation logic; added CountDigits helper for efficient numeric formatting
src/coreclr/tools/Common/Internal/Text/Utf8String.csAdded Concat method to combine multiple UTF-8 strings without conversion
src/coreclr/tools/Common/Internal/Text/Utf8StringBuilder.csAdded constructor accepting initial capacity parameter
src/coreclr/tools/Common/Compiler/ObjectWriter/SectionWriter.csAdded WriteUtf8String(Utf8String) overload to write UTF-8 strings directly
src/coreclr/tools/Common/TypeSystem/TypesDebugInfoWriter/TypesDebugInfoWriter.csChanged interface methods and type descriptors to use Utf8String
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/Dwarf/DwarfInfoWriter.csAdded WriteStringReference(Utf8String) overload for UTF-8 string references
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/Dwarf/DwarfBuilder.csChanged GetMangledName to return Utf8String
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewTypesBuilder.csUpdated user-defined types to use Utf8String; added Write(Utf8String) overload
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewSymbolsBuilder.csUpdated WriteUserDefinedTypes signature and added Write(Utf8String) overload
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/WindowsNodeMangler.csAdded ToString() call to convert UTF-8 result to string for method table names
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/UnixNodeMangler.csAdded ToString() call to convert UTF-8 result to string for method table names

Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment thread...coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewTypesBuilder.cs
Comment thread...reclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewSymbolsBuilder.cs
am11
am11 reviewed Dec 3, 2025
View reviewed changes
Comment threadsrc/coreclr/tools/Common/Internal/Text/Utf8String.cs
This was referenced Dec 3, 2025
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agocke
agocke approved these changes Dec 3, 2025
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Nice! Do we have any unit tests for the name mangler? If not I could have copilot give it a shot

Comment threadsrc/coreclr/tools/aot/ILCompiler.Compiler/Compiler/UnixNodeMangler.cs Outdated
Comment threadsrc/coreclr/tools/aot/ILCompiler.Compiler/Compiler/WindowsNodeMangler.cs Outdated
@MichalStrehovsky

MichalStrehovsky commented Dec 3, 2025•
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Nice! Do we have any unit tests for the name mangler? If not I could have copilot give it a shot

I validated this by comparing the output object file (it was byte identical). We don't have unit tests; we can try giving it a shot if copilot comes up with something useful. But name mangling is typically not touched so I can only see the unit test getting in the way if we ever change how we want to mangle things (it is an implementation detail and not a contract). A unit test would definitely make this PR more annoying to do.

@build-analysisbuild-analysisBot mentioned this pull request Dec 3, 2025
Closed
@MichalStrehovsky
MichalStrehovsky merged commit f7a3ad3 into dotnet:mainDec 3, 2025
92 of 96 checks passed
@MichalStrehovsky
MichalStrehovsky deleted the uf8mangler branch December 3, 2025 13:16
@dotnet-maestrodotnet-maestroBot mentioned this pull request Dec 4, 2025
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, '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

Switch NameMangler to UTF-8 - #122128

Merged
MichalStrehovsky merged 2 commits into
dotnet:mainfrom
MichalStrehovsky:uf8mangler
Dec 3, 2025
Merged

Switch NameMangler to UTF-8#122128
MichalStrehovsky merged 2 commits into
dotnet:mainfrom
MichalStrehovsky:uf8mangler

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@MichalStrehovsky

@MichalStrehovskyMichalStrehovsky commented Dec 2, 2025

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Removes some unnecessary UTF-8 -> UTF-16 -> UTF-8 conversions.

Before this change, when compiling hello world: 529000 byte[] allocations, 403000 string allocations.
After this change: 552000 byte[] allocations, 302000 string allocations.

Cc @dotnet/ilc-contrib

CopilotAI review requested due to automatic review settings December 2, 2025 23:05
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Tagging subscribers to this area: @agocke, @MichalStrehovsky, @jkotas
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Pull request overview

This PR optimizes the ILCompiler by switching the NameMangler from UTF-16 strings to UTF-8, eliminating unnecessary encoding conversions during compilation. The change reduces string allocations by approximately 101,000 instances when compiling a hello world application (from 403,000 to 302,000), though it increases byte array allocations slightly (from 529,000 to 552,000).

Key Changes:

  • Modified NameMangler.GetMangledTypeName() and related methods to return Utf8String instead of string
  • Implemented UTF-8 versions of name sanitization and disambiguation logic
  • Added UTF-8 string writing overloads in debug info builders and section writers

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 6 comments.

Show a summary per file
FileDescription
src/coreclr/tools/Common/Compiler/NameMangler.csChanged abstract method signatures from string to Utf8String for type and name mangling
src/coreclr/tools/Common/Compiler/NativeAotNameMangler.csImplemented UTF-8 versions of name mangling, sanitization, and disambiguation logic; added CountDigits helper for efficient numeric formatting
src/coreclr/tools/Common/Internal/Text/Utf8String.csAdded Concat method to combine multiple UTF-8 strings without conversion
src/coreclr/tools/Common/Internal/Text/Utf8StringBuilder.csAdded constructor accepting initial capacity parameter
src/coreclr/tools/Common/Compiler/ObjectWriter/SectionWriter.csAdded WriteUtf8String(Utf8String) overload to write UTF-8 strings directly
src/coreclr/tools/Common/TypeSystem/TypesDebugInfoWriter/TypesDebugInfoWriter.csChanged interface methods and type descriptors to use Utf8String
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/Dwarf/DwarfInfoWriter.csAdded WriteStringReference(Utf8String) overload for UTF-8 string references
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/Dwarf/DwarfBuilder.csChanged GetMangledName to return Utf8String
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewTypesBuilder.csUpdated user-defined types to use Utf8String; added Write(Utf8String) overload
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewSymbolsBuilder.csUpdated WriteUserDefinedTypes signature and added Write(Utf8String) overload
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/WindowsNodeMangler.csAdded ToString() call to convert UTF-8 result to string for method table names
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/UnixNodeMangler.csAdded ToString() call to convert UTF-8 result to string for method table names

Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment thread...coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewTypesBuilder.cs
Comment thread...reclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewSymbolsBuilder.cs
am11
am11 reviewed Dec 3, 2025
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Comment threadsrc/coreclr/tools/Common/Internal/Text/Utf8String.cs
This was referenced Dec 3, 2025
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agocke approved these changes Dec 3, 2025
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Nice! Do we have any unit tests for the name mangler? If not I could have copilot give it a shot

Comment threadsrc/coreclr/tools/aot/ILCompiler.Compiler/Compiler/UnixNodeMangler.cs Outdated
Comment threadsrc/coreclr/tools/aot/ILCompiler.Compiler/Compiler/WindowsNodeMangler.cs Outdated
@MichalStrehovsky

MichalStrehovsky commented Dec 3, 2025•
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Nice! Do we have any unit tests for the name mangler? If not I could have copilot give it a shot

I validated this by comparing the output object file (it was byte identical). We don't have unit tests; we can try giving it a shot if copilot comes up with something useful. But name mangling is typically not touched so I can only see the unit test getting in the way if we ever change how we want to mangle things (it is an implementation detail and not a contract). A unit test would definitely make this PR more annoying to do.

@build-analysisbuild-analysisBot mentioned this pull request Dec 3, 2025
Closed
@MichalStrehovsky
MichalStrehovsky merged commit f7a3ad3 into dotnet:mainDec 3, 2025
92 of 96 checks passed
@MichalStrehovsky
MichalStrehovsky deleted the uf8mangler branch December 3, 2025 13:16
@dotnet-maestrodotnet-maestroBot mentioned this pull request Dec 4, 2025
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, '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

Switch NameMangler to UTF-8 - #122128

Merged
MichalStrehovsky merged 2 commits into
dotnet:mainfrom
MichalStrehovsky:uf8mangler
Dec 3, 2025
Merged

Switch NameMangler to UTF-8#122128
MichalStrehovsky merged 2 commits into
dotnet:mainfrom
MichalStrehovsky:uf8mangler

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@MichalStrehovskyMichalStrehovsky commented Dec 2, 2025

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Removes some unnecessary UTF-8 -> UTF-16 -> UTF-8 conversions.

Before this change, when compiling hello world: 529000 byte[] allocations, 403000 string allocations.
After this change: 552000 byte[] allocations, 302000 string allocations.

Cc @dotnet/ilc-contrib

CopilotAI review requested due to automatic review settings December 2, 2025 23:05
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Tagging subscribers to this area: @agocke, @MichalStrehovsky, @jkotas
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Pull request overview

This PR optimizes the ILCompiler by switching the NameMangler from UTF-16 strings to UTF-8, eliminating unnecessary encoding conversions during compilation. The change reduces string allocations by approximately 101,000 instances when compiling a hello world application (from 403,000 to 302,000), though it increases byte array allocations slightly (from 529,000 to 552,000).

Key Changes:

  • Modified NameMangler.GetMangledTypeName() and related methods to return Utf8String instead of string
  • Implemented UTF-8 versions of name sanitization and disambiguation logic
  • Added UTF-8 string writing overloads in debug info builders and section writers

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 6 comments.

Show a summary per file
FileDescription
src/coreclr/tools/Common/Compiler/NameMangler.csChanged abstract method signatures from string to Utf8String for type and name mangling
src/coreclr/tools/Common/Compiler/NativeAotNameMangler.csImplemented UTF-8 versions of name mangling, sanitization, and disambiguation logic; added CountDigits helper for efficient numeric formatting
src/coreclr/tools/Common/Internal/Text/Utf8String.csAdded Concat method to combine multiple UTF-8 strings without conversion
src/coreclr/tools/Common/Internal/Text/Utf8StringBuilder.csAdded constructor accepting initial capacity parameter
src/coreclr/tools/Common/Compiler/ObjectWriter/SectionWriter.csAdded WriteUtf8String(Utf8String) overload to write UTF-8 strings directly
src/coreclr/tools/Common/TypeSystem/TypesDebugInfoWriter/TypesDebugInfoWriter.csChanged interface methods and type descriptors to use Utf8String
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/Dwarf/DwarfInfoWriter.csAdded WriteStringReference(Utf8String) overload for UTF-8 string references
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/Dwarf/DwarfBuilder.csChanged GetMangledName to return Utf8String
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewTypesBuilder.csUpdated user-defined types to use Utf8String; added Write(Utf8String) overload
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewSymbolsBuilder.csUpdated WriteUserDefinedTypes signature and added Write(Utf8String) overload
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/WindowsNodeMangler.csAdded ToString() call to convert UTF-8 result to string for method table names
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/UnixNodeMangler.csAdded ToString() call to convert UTF-8 result to string for method table names

Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment thread...coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewTypesBuilder.cs
Comment thread...reclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewSymbolsBuilder.cs
am11
am11 reviewed Dec 3, 2025
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Comment threadsrc/coreclr/tools/Common/Internal/Text/Utf8String.cs
This was referenced Dec 3, 2025
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agocke
agocke approved these changes Dec 3, 2025
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Nice! Do we have any unit tests for the name mangler? If not I could have copilot give it a shot

Comment threadsrc/coreclr/tools/aot/ILCompiler.Compiler/Compiler/UnixNodeMangler.cs Outdated
Comment threadsrc/coreclr/tools/aot/ILCompiler.Compiler/Compiler/WindowsNodeMangler.cs Outdated
@MichalStrehovsky

MichalStrehovsky commented Dec 3, 2025•
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Nice! Do we have any unit tests for the name mangler? If not I could have copilot give it a shot

I validated this by comparing the output object file (it was byte identical). We don't have unit tests; we can try giving it a shot if copilot comes up with something useful. But name mangling is typically not touched so I can only see the unit test getting in the way if we ever change how we want to mangle things (it is an implementation detail and not a contract). A unit test would definitely make this PR more annoying to do.

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@MichalStrehovsky
MichalStrehovsky merged commit f7a3ad3 into dotnet:mainDec 3, 2025
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MichalStrehovsky deleted the uf8mangler branch December 3, 2025 13:16
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, '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); } })(); })();
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Switch NameMangler to UTF-8 - #122128

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MichalStrehovsky merged 2 commits into
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MichalStrehovsky:uf8mangler
Dec 3, 2025
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Switch NameMangler to UTF-8#122128
MichalStrehovsky merged 2 commits into
dotnet:mainfrom
MichalStrehovsky:uf8mangler

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@MichalStrehovsky

@MichalStrehovskyMichalStrehovsky commented Dec 2, 2025

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Removes some unnecessary UTF-8 -> UTF-16 -> UTF-8 conversions.

Before this change, when compiling hello world: 529000 byte[] allocations, 403000 string allocations.
After this change: 552000 byte[] allocations, 302000 string allocations.

Cc @dotnet/ilc-contrib

CopilotAI review requested due to automatic review settings December 2, 2025 23:05
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Pull request overview

This PR optimizes the ILCompiler by switching the NameMangler from UTF-16 strings to UTF-8, eliminating unnecessary encoding conversions during compilation. The change reduces string allocations by approximately 101,000 instances when compiling a hello world application (from 403,000 to 302,000), though it increases byte array allocations slightly (from 529,000 to 552,000).

Key Changes:

  • Modified NameMangler.GetMangledTypeName() and related methods to return Utf8String instead of string
  • Implemented UTF-8 versions of name sanitization and disambiguation logic
  • Added UTF-8 string writing overloads in debug info builders and section writers

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 6 comments.

Show a summary per file
FileDescription
src/coreclr/tools/Common/Compiler/NameMangler.csChanged abstract method signatures from string to Utf8String for type and name mangling
src/coreclr/tools/Common/Compiler/NativeAotNameMangler.csImplemented UTF-8 versions of name mangling, sanitization, and disambiguation logic; added CountDigits helper for efficient numeric formatting
src/coreclr/tools/Common/Internal/Text/Utf8String.csAdded Concat method to combine multiple UTF-8 strings without conversion
src/coreclr/tools/Common/Internal/Text/Utf8StringBuilder.csAdded constructor accepting initial capacity parameter
src/coreclr/tools/Common/Compiler/ObjectWriter/SectionWriter.csAdded WriteUtf8String(Utf8String) overload to write UTF-8 strings directly
src/coreclr/tools/Common/TypeSystem/TypesDebugInfoWriter/TypesDebugInfoWriter.csChanged interface methods and type descriptors to use Utf8String
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/Dwarf/DwarfInfoWriter.csAdded WriteStringReference(Utf8String) overload for UTF-8 string references
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/Dwarf/DwarfBuilder.csChanged GetMangledName to return Utf8String
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewTypesBuilder.csUpdated user-defined types to use Utf8String; added Write(Utf8String) overload
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewSymbolsBuilder.csUpdated WriteUserDefinedTypes signature and added Write(Utf8String) overload
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/WindowsNodeMangler.csAdded ToString() call to convert UTF-8 result to string for method table names
src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/UnixNodeMangler.csAdded ToString() call to convert UTF-8 result to string for method table names

Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment threadsrc/coreclr/tools/Common/Compiler/NativeAotNameMangler.cs
Comment thread...coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewTypesBuilder.cs
Comment thread...reclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/CodeView/CodeViewSymbolsBuilder.cs
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Comment threadsrc/coreclr/tools/Common/Internal/Text/Utf8String.cs
This was referenced Dec 3, 2025
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Nice! Do we have any unit tests for the name mangler? If not I could have copilot give it a shot

Comment threadsrc/coreclr/tools/aot/ILCompiler.Compiler/Compiler/UnixNodeMangler.cs Outdated
Comment threadsrc/coreclr/tools/aot/ILCompiler.Compiler/Compiler/WindowsNodeMangler.cs Outdated
@MichalStrehovsky

MichalStrehovsky commented Dec 3, 2025•
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Nice! Do we have any unit tests for the name mangler? If not I could have copilot give it a shot

I validated this by comparing the output object file (it was byte identical). We don't have unit tests; we can try giving it a shot if copilot comes up with something useful. But name mangling is typically not touched so I can only see the unit test getting in the way if we ever change how we want to mangle things (it is an implementation detail and not a contract). A unit test would definitely make this PR more annoying to do.

@build-analysisbuild-analysisBot mentioned this pull request Dec 3, 2025
Closed
@MichalStrehovsky
MichalStrehovsky merged commit f7a3ad3 into dotnet:mainDec 3, 2025
92 of 96 checks passed
@MichalStrehovsky
MichalStrehovsky deleted the uf8mangler branch December 3, 2025 13:16
@dotnet-maestrodotnet-maestroBot mentioned this pull request Dec 4, 2025
Merged
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@agockeagockeagocke approved these changes
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@am11am11am11 left review comments
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