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[PowerPC][AIX] Support #pragma comment copyright for AIX#1

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[PowerPC][AIX] Support #pragma comment copyright for AIX#1
tonykuttai wants to merge 18 commits into
mandlebug:XCOFFAssociatedMetadatafrom
tonykuttai:tvarghese/pragma-comment-copyright

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@tonykuttai tonykuttai commented Oct 18, 2025

Add support for the #pragma comment (copyright, "Copyright info") directive for AIX.

This builds on top of PR #159096

Refernce: XL documentation for #pragma comment

Comment thread llvm/test/Transforms/CopyrightMetadata/copyright-metadata.ll Outdated
Comment thread llvm/test/Transforms/CopyrightMetadata/copyright-metadata.ll Outdated
Comment thread clang/lib/Parse/ParsePragma.cpp Outdated
Comment thread clang/lib/CodeGen/CodeGenModule.cpp Outdated
Comment thread clang/lib/CodeGen/CodeGenModule.cpp Outdated
Comment thread llvm/lib/Transforms/Utils/CopyrightMetadataPass.cpp Outdated
Comment thread llvm/lib/Transforms/Utils/CopyrightMetadataPass.cpp Outdated
Comment thread llvm/lib/Transforms/Utils/CopyrightMetadataPass.cpp Outdated
Comment thread llvm/lib/Transforms/Utils/CopyrightMetadataPass.cpp Outdated
@@ -0,0 +1,110 @@
// REQUIRES: powerpc-registered-target, system-aix, clang
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I don't think this test fits with the LLVM unit testing philosophy.

My understanding is that we have tests

  • for the front-end generation of the aix.copyright.comment metadata, and
  • for the transformation of the aix.copyright.comment metadata to implicit.ref, etc.

What we do not have are targeted tests that specifically verify that the transformation is run at the right point in the various possible pipelines.

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you are right. Removed this test.

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@tonykuttai tonykuttai Oct 21, 2025

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What we do not have are targeted tests that specifically verify that the transformation is run at the right point in the various possible pipelines.

Added the opt levels testing to llvm/test/Transforms/CopyrightMetadata/copyright-metadata.ll. Do we need an end-to-end test ?

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Do we need a end-to-end test ?

I can't say that we shouldn't have one. It is just that I am not aware of there being any in upstream LLVM that involve the linker (except when it's an lld test).

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I couldn't find anything similar as well.

@tonykuttai tonykuttai force-pushed the tvarghese/pragma-comment-copyright branch from 438f04c to cfa6019 Compare October 21, 2025 14:22
Comment thread llvm/test/Transforms/CopyrightMetadata/copyright-metadata.ll Outdated
Comment thread clang/lib/CodeGen/CodeGenModule.h Outdated
@tonykuttai tonykuttai force-pushed the tvarghese/pragma-comment-copyright branch from 252f063 to 82254ee Compare October 22, 2025 11:58
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Added the test clang/test/CodeGen/PowerPC/pragma-comment-copyright-aix-modules.cpp to test the C++ 20 Modules getting ignored in the importing TU.

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Some partial review comments...

Comment on lines +4 to +7
; RUN: opt --O0 -S %s -o - | FileCheck %s --check-prefixes=CHECK,CHECK-O0
; RUN: opt --O1 -S %s -o - | FileCheck %s --check-prefixes=CHECK,CHECK-ON
; RUN: opt --O2 -S %s -o - | FileCheck %s --check-prefixes=CHECK,CHECK-ON
; RUN: opt --O3 -S %s -o - | FileCheck %s --check-prefixes=CHECK,CHECK-ON
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I'm not familiar enough with how the pipelines are built between different tools (clang, opt, etc.) to know if this is the right way to check that the pass is in the pipeline at the right place (especially for LTO).

@w2yehia @mandlebug, your input would be appreciated.

; - Emits the string in a dedicated read-only csect
;
; CHECK-ASM: .ref __aix_copyright_str
; CHECK-ASM: .csect __aix_copyright[RO],2
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Sorry for the churn. The check in llvm/test/Transforms/CopyrightMetadata/copyright-metadata.ll for constant in the IR is sufficient for establishing that we are generating as read-only, so the testing request from #1 (comment) was already satisfied (and we don't need this test just to cover that).

It is still a question whether we want to group the strings into one csect (which probably has no effect except under "full" LTO where it will increase the chance of the string being kept).

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ok, sure. Removing the llvm/test/CodeGen/PowerPC/pragma-comment-copyright-aix.ll.

It is still a question whether we want to group the strings into one csect (which probably has no effect except under "full" LTO where it will increase the chance of the string being kept).

Are there any downsides to the current approach ? I think it is cleaner to group them seperately in a csect.

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Are there any downsides to the current approach ?

It generates "false positives" to the question of whether the content associated with the copyright string was actually retained/relevant to the result.

Comment thread clang/lib/Parse/ParsePragma.cpp
Comment thread clang/lib/Parse/ParsePragma.cpp Outdated
Comment thread clang/lib/Parse/ParsePragma.cpp Outdated
Comment thread clang/lib/CodeGen/CodeGenModule.cpp Outdated
Comment thread clang/lib/CodeGen/CodeGenModule.cpp Outdated
Comment thread clang/lib/CodeGen/CodeGenModule.h Outdated
Comment thread clang/lib/CodeGen/CodeGenModule.cpp Outdated
Comment thread clang/lib/CodeGen/CodeGenModule.h Outdated
Comment thread clang/test/CodeGen/PowerPC/pragma-comment-copyright-aix-modules.cpp Outdated
Comment thread clang/lib/CodeGen/CodeGenModule.cpp Outdated
Comment thread clang/lib/CodeGen/CodeGenModule.cpp Outdated
Comment thread clang/lib/CodeGen/CodeGenModule.h Outdated
Comment thread clang/lib/Parse/ParsePragma.cpp Outdated
Comment thread llvm/lib/Transforms/Utils/CopyrightMetadataPass.cpp Outdated
Comment thread llvm/lib/Transforms/Utils/CopyrightMetadataPass.cpp
Comment thread llvm/lib/Transforms/Utils/CopyrightMetadataPass.cpp Outdated
Comment thread llvm/lib/Transforms/Utils/CopyrightMetadataPass.cpp Outdated
Comment thread llvm/lib/Transforms/Utils/CopyrightMetadataPass.cpp Outdated
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Please add updates to existing tests so that they continue to pass. For example, llvm/test/Other/new-pm-defaults.ll fails with:

# .---command stderr------------
# | /llvm/test/Other/new-pm-defaults.ll:241:23: error: CHECK-DEFAULT-NEXT: is not on the line after the previous match
# | ; CHECK-DEFAULT-NEXT: Running pass: EliminateAvailableExternallyPass
# |                       ^
# | <stdin>:100:1: note: 'next' match was here
# | Running pass: EliminateAvailableExternallyPass on [module]
# | ^
# | <stdin>:98:28: note: previous match ended here
# | Running pass: GlobalDCEPass on [module]
# |                            ^
# | <stdin>:99:1: note: non-matching line after previous match is here
# | Running pass: CopyrightMetadataPass on [module]
# | ^

Comment thread clang/test/CodeGen/PowerPC/pragma-comment-copyright-aix.c Outdated
Comment thread llvm/include/llvm/Transforms/Utils/CopyrightMetadataPass.h Outdated
Comment thread llvm/test/Transforms/CopyrightMetadata/copyright-metadata.ll Outdated
Add support for the associated metadata node for AIX.. Map it to
the .ref assembly directive. Placing the node on a symbol will cause
the back end to emit a .ref directive in the section of the global the
metadata is placed on. the .ref will refrence the associated symbol
which will keep it alive if the section is not garbage collected.
* Added support for emitting ref metadata on functions.
* Added testing for ref metadata on functions.
* Fixed up lang ref description.
* Renamed tests to match metadatas nameing.
Propagate the metadata from callee to caller on inlining. Also adds a
test verifying that the metadata is maintained when cloning a function.
@mandlebug mandlebug force-pushed the XCOFFAssociatedMetadata branch from 325741a to 4d6f365 Compare December 3, 2025 20:37
@tonykuttai tonykuttai force-pushed the tvarghese/pragma-comment-copyright branch from 19a0c93 to a2904ba Compare December 5, 2025 05:55
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Rebased the branch with latest updates from mandlebug:XCOFFAssociatedMetadata

Comment thread llvm/lib/Passes/PassRegistry.def Outdated
MODULE_PASS("constmerge", ConstantMergePass())
MODULE_PASS("coro-cleanup", CoroCleanupPass())
MODULE_PASS("coro-early", CoroEarlyPass())
MODULE_PASS("copyright-metadata", CopyrightMetadataPass())
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The name of this pass should be updated too so it is independent of the word "copyright". Nothing in the IR refers to copyright. To make it easier for people to understand, the pass name should reflect the IR meta data it is processing.

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How about LowerCommentStringPass or LowerLoadTimeCommentPass?

// Input IR:
// !comment_string.loadtime = !{!"Copyright"}
// Output IR:
// @__loadtime_copyright_str = internal constant [N x i8] c"Copyright\00",
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Rename this to __loadtime_comment_str.

// !comment_string.loadtime = !{!"Copyright"}
// Output IR:
// @__loadtime_copyright_str = internal constant [N x i8] c"Copyright\00",
// section "__copyright_comment"
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I assume this can be renamed too. Something like __loadtime_comment

@mandlebug mandlebug force-pushed the XCOFFAssociatedMetadata branch from e5449d5 to 46023a3 Compare January 8, 2026 18:14
mandlebug pushed a commit that referenced this pull request Jan 22, 2026
**This patch adds a marker to make hidden frames more explicit.**

---

Hidden frames can be confusing for some users, who see that the indexes
of the frames in a backtrace are not contiguous. This patch aims to
lessen the confusion by adding a delimiter for the first and last non
hidden frame, i.e the boundaries.

IDE's like Xcode and VSCode represent those in the UI by having the
hidden frames either greyed out or collapsed.

It's not possible to do this in the CLI, therefore, this patch makes use
of 2 unicode characters to mark the beginning and end of the hidden
frames range.

This patch depends on:
- llvm#168603

# Examples

In the example below, frame `llvm#2` to `llvm#7` are is hidden, and therefore,
frame `#1` is the first non hidden frame of the range while frame `llvm#8`
is the last non hidden frame:
<img width="488" height="112" alt="Screenshot 2025-11-18 at 18 41 11"
src="https://github.com/user-attachments/assets/a21431da-9729-4cf0-a6bc-024aa306fc45"
/>

If the selected frame is one of the 2 boundary frames, we replace the
delimiter character with the select character (`*`).

<img width="487" height="111" alt="Screenshot 2025-11-18 at 18 41 03"
src="https://github.com/user-attachments/assets/5616fa81-6db6-457d-9d1e-bbe46e710c26"
/>
<img width="488" height="111" alt="Screenshot 2025-11-18 at 18 40 55"
src="https://github.com/user-attachments/assets/93dfa6cf-0956-4718-b31c-f965ec72b56d"
/>
mandlebug pushed a commit that referenced this pull request Jan 22, 2026
… all redeclarations (llvm#176188)

Fix handling of `lifetimebound` attributes on implicit `this` parameters across function redeclarations.

Previously, the lifetime analysis would miss `lifetimebound` attributes on implicit `this` parameters if they were only present on certain redeclarations of a method. This could lead to false negatives in the lifetime safety analysis. This change ensures that if any redeclaration of a method has the attribute, it will be properly detected and used in the analysis.

I can't seem to work around the crash in the earlier attempt llvm#172146.

Reproducer of the original crash:

```cpp
struct a {
  a &b() [[_Clang::__lifetimebound__]];
};
a &a::b() {}
```
This only crashes with `-target i686-w64-mingw32`. `bin/clang++ -c a.cpp` works fine.
Problematic merging logic:
```cpp
 // If Old has lifetimebound but New doesn't, add it to New.
  if (OldLBAttr && !NewLBAttr) {
    QualType NewMethodType = New->getType();
    QualType AttributedType =
        S.Context.getAttributedType(OldLBAttr, NewMethodType, NewMethodType);
    TypeLocBuilder TLB;
    TLB.pushFullCopy(NewTSI->getTypeLoc());
    AttributedTypeLoc TyLoc = TLB.push<AttributedTypeLoc>(AttributedType); // Crashes.
    TyLoc.setAttr(OldLBAttr);
    New->setType(AttributedType);
    New->setTypeSourceInfo(TLB.getTypeSourceInfo(S.Context, AttributedType));
  }
```

<details>
<summary>Crash</summary>

```
clang++: /REDACTED//llvm-project/clang/lib/Sema/TypeLocBuilder.cpp:89: TypeLoc clang::TypeLocBuilder::pushImpl(QualType, size_t, unsigned int): Assertion `TLast == LastTy && "mismatch between last type and new type's inner type"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.      Program arguments: bin/clang++ -target i686-w64-mingw32 -c /REDACTED//a.cpp
1.      /REDACTED//a.cpp:4:11: current parser token '{'
 #0 0x000055971cfcb838 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /REDACTED//llvm-project/llvm/lib/Support/Unix/Signals.inc:842:13
 #1 0x000055971cfc9374 llvm::sys::RunSignalHandlers() /REDACTED//llvm-project/llvm/lib/Support/Signals.cpp:109:18
 llvm#2 0x000055971cfcaf0c llvm::sys::CleanupOnSignal(unsigned long) /REDACTED//llvm-project/llvm/lib/Support/Unix/Signals.inc:0:3
 llvm#3 0x000055971cf38116 (anonymous namespace)::CrashRecoveryContextImpl::HandleCrash(int, unsigned long) /REDACTED//llvm-project/llvm/lib/Support/CrashRecoveryContext.cpp:73:5
 llvm#4 0x000055971cf38116 CrashRecoverySignalHandler(int) /REDACTED//llvm-project/llvm/lib/Support/CrashRecoveryContext.cpp:390:51
 llvm#5 0x00007fe9ebe49df0 (/lib/x86_64-linux-gnu/libc.so.6+0x3fdf0)
 llvm#6 0x00007fe9ebe9e95c __pthread_kill_implementation ./nptl/pthread_kill.c:44:76
 llvm#7 0x00007fe9ebe49cc2 raise ./signal/../sysdeps/posix/raise.c:27:6
 llvm#8 0x00007fe9ebe324ac abort ./stdlib/abort.c:81:3
 llvm#9 0x00007fe9ebe32420 __assert_perror_fail ./assert/assert-perr.c:31:1
llvm#10 0x000055971f969ade clang::TypeLocBuilder::pushImpl(clang::QualType, unsigned long, unsigned int) /REDACTED//llvm-project/clang/lib/Sema/TypeLocBuilder.cpp:93:3
llvm#11 0x000055971f237255 clang::QualType::hasLocalQualifiers() const /REDACTED//llvm-project/clang/include/clang/AST/TypeBase.h:1065:37
llvm#12 0x000055971f237255 clang::ConcreteTypeLoc<clang::UnqualTypeLoc, clang::AttributedTypeLoc, clang::AttributedType, clang::AttributedLocInfo>::isKind(clang::TypeLoc const&) /REDACTED//llvm-project/clang/include/clang/AST/TypeLoc.h:392:26
llvm#13 0x000055971f237255 clang::AttributedTypeLoc clang::TypeLoc::castAs<clang::AttributedTypeLoc>() const /REDACTED//llvm-project/clang/include/clang/AST/TypeLoc.h:79:5
llvm#14 0x000055971f237255 clang::AttributedTypeLoc clang::TypeLocBuilder::push<clang::AttributedTypeLoc>(clang::QualType) /REDACTED//llvm-project/clang/lib/Sema/TypeLocBuilder.h:106:47
llvm#15 0x000055971f280cc8 clang::AttributedTypeLoc::setAttr(clang::Attr const*) /REDACTED//llvm-project/clang/include/clang/AST/TypeLoc.h:1035:30
llvm#16 0x000055971f280cc8 mergeLifetimeBoundAttrOnMethod(clang::Sema&, clang::CXXMethodDecl*, clang::CXXMethodDecl const*) /REDACTED//llvm-project/clang/lib/Sema/SemaDecl.cpp:4497:11
llvm#17 0x000055971f280cc8 clang::Sema::MergeCompatibleFunctionDecls(clang::FunctionDecl*, clang::FunctionDecl*, clang::Scope*, bool) /REDACTED//llvm-project/clang/lib/Sema/SemaDecl.cpp:4528:5
llvm#18 0x000055971f27eb1f clang::Sema::MergeFunctionDecl(clang::FunctionDecl*, clang::NamedDecl*&, clang::Scope*, bool, bool) /REDACTED//llvm-project/clang/lib/Sema/SemaDecl.cpp:0:0
llvm#19 0x000055971f29c256 clang::Sema::CheckFunctionDeclaration(clang::Scope*, clang::FunctionDecl*, clang::LookupResult&, bool, bool) /REDACTED//llvm-project/clang/lib/Sema/SemaDecl.cpp:12371:9
llvm#20 0x000055971f28dab0 clang::Declarator::setRedeclaration(bool) /REDACTED//llvm-project/clang/include/clang/Sema/DeclSpec.h:2738:51
llvm#21 0x000055971f28dab0 clang::Sema::ActOnFunctionDeclarator(clang::Scope*, clang::Declarator&, clang::DeclContext*, clang::TypeSourceInfo*, clang::LookupResult&, llvm::MutableArrayRef<clang::TemplateParameterList*>, bool&) /REDACTED//llvm-project/clang/lib/Sema/SemaDecl.cpp:10877:9
llvm#22 0x000055971f2890fc clang::Sema::HandleDeclarator(clang::Scope*, clang::Declarator&, llvm::MutableArrayRef<clang::TemplateParameterList*>) /REDACTED//llvm-project/clang/lib/Sema/SemaDecl.cpp:0:11
llvm#23 0x000055971f2aab99 clang::Sema::ActOnStartOfFunctionDef(clang::Scope*, clang::Declarator&, llvm::MutableArrayRef<clang::TemplateParameterList*>, clang::SkipBodyInfo*, clang::Sema::FnBodyKind) /REDACTED//llvm-project/clang/lib/Sema/SemaDecl.cpp:15904:15
llvm#24 0x000055971efab286 clang::Parser::ParseFunctionDefinition(clang::ParsingDeclarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::LateParsedAttrList*) /REDACTED//llvm-project/clang/lib/Parse/Parser.cpp:1364:23
llvm#25 0x000055971f013b40 clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::Parser::ParsedTemplateInfo&, clang::SourceLocation*, clang::Parser::ForRangeInit*) /REDACTED//llvm-project/clang/lib/Parse/ParseDecl.cpp:2268:18
llvm#26 0x000055971efaa54f clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) /REDACTED//llvm-project/clang/lib/Parse/Parser.cpp:0:10
llvm#27 0x000055971efa9e36 clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) /REDACTED//llvm-project/clang/lib/Parse/Parser.cpp:1202:12
llvm#28 0x000055971efa8df8 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) /REDACTED//llvm-project/clang/lib/Parse/Parser.cpp:0:14
llvm#29 0x000055971efa7574 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) /REDACTED//llvm-project/clang/lib/Parse/Parser.cpp:743:10
llvm#30 0x000055971ef9c0ee clang::ParseAST(clang::Sema&, bool, bool) /REDACTED//llvm-project/clang/lib/Parse/ParseAST.cpp:169:5
llvm#31 0x000055971dbcdad6 clang::FrontendAction::Execute() /REDACTED//llvm-project/clang/lib/Frontend/FrontendAction.cpp:1317:10
llvm#32 0x000055971db3c5fd llvm::Error::getPtr() const /REDACTED//llvm-project/llvm/include/llvm/Support/Error.h:278:42
llvm#33 0x000055971db3c5fd llvm::Error::operator bool() /REDACTED//llvm-project/llvm/include/llvm/Support/Error.h:241:16
llvm#34 0x000055971db3c5fd clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) /REDACTED//llvm-project/clang/lib/Frontend/CompilerInstance.cpp:1006:23
llvm#35 0x000055971dcb4f9c clang::ExecuteCompilerInvocation(clang::CompilerInstance*) /REDACTED//llvm-project/clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp:310:25
llvm#36 0x000055971a5e655e cc1_main(llvm::ArrayRef<char const*>, char const*, void*) /REDACTED//llvm-project/clang/tools/driver/cc1_main.cpp:304:15
llvm#37 0x000055971a5e29cb ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>) /REDACTED//llvm-project/clang/tools/driver/driver.cpp:226:12
llvm#38 0x000055971a5e4c1d clang_main(int, char**, llvm::ToolContext const&)::$_0::operator()(llvm::SmallVectorImpl<char const*>&) const /REDACTED//llvm-project/clang/tools/driver/driver.cpp:0:12
llvm#39 0x000055971a5e4c1d int llvm::function_ref<int (llvm::SmallVectorImpl<char const*>&)>::callback_fn<clang_main(int, char**, llvm::ToolContext const&)::$_0>(long, llvm::SmallVectorImpl<char const*>&) /REDACTED//llvm-project/llvm/include/llvm/ADT/STLFunctionalExtras.h:46:12
llvm#40 0x000055971d9bfe79 clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const::$_0::operator()() const /REDACTED//llvm-project/clang/lib/Driver/Job.cpp:442:30
llvm#41 0x000055971d9bfe79 void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const::$_0>(long) /REDACTED//llvm-project/llvm/include/llvm/ADT/STLFunctionalExtras.h:46:12
llvm#42 0x000055971cf37dbe llvm::function_ref<void ()>::operator()() const /REDACTED//llvm-project/llvm/include/llvm/ADT/STLFunctionalExtras.h:0:12
llvm#43 0x000055971cf37dbe llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) /REDACTED//llvm-project/llvm/lib/Support/CrashRecoveryContext.cpp:426:3
llvm#44 0x000055971d9bf5ac clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const /REDACTED//llvm-project/clang/lib/Driver/Job.cpp:442:7
llvm#45 0x000055971d98422c clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const /REDACTED//llvm-project/clang/lib/Driver/Compilation.cpp:196:15
llvm#46 0x000055971d984447 clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const /REDACTED//llvm-project/clang/lib/Driver/Compilation.cpp:246:13
llvm#47 0x000055971d99ee08 llvm::SmallVectorBase<unsigned int>::empty() const /REDACTED//llvm-project/llvm/include/llvm/ADT/SmallVector.h:83:46
llvm#48 0x000055971d99ee08 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) /REDACTED//llvm-project/clang/lib/Driver/Driver.cpp:2265:23
llvm#49 0x000055971a5e2303 clang_main(int, char**, llvm::ToolContext const&) /REDACTED//llvm-project/clang/tools/driver/driver.cpp:414:21
llvm#50 0x000055971a5f2527 main /usr/local/google/home/usx/build/tools/clang/tools/driver/clang-driver.cpp:17:10
llvm#51 0x00007fe9ebe33ca8 __libc_start_call_main ./csu/../sysdeps/nptl/libc_start_call_main.h:74:3
llvm#52 0x00007fe9ebe33d65 call_init ./csu/../csu/libc-start.c:128:20
llvm#53 0x00007fe9ebe33d65 __libc_start_main ./csu/../csu/libc-start.c:347:5
llvm#54 0x000055971a5e0361 _start (bin/clang+++0x6636361)
clang++: error: clang frontend command failed with exit code 134 (use -v to see invocation)
clang version 23.0.0git (https://github.com/llvm/llvm-project.git 282a065)
Target: i686-w64-windows-gnu
Thread model: posix
InstalledDir: /usr/local/google/home/usx/build/bin
Build config: +assertions
clang++: note: diagnostic msg: 
********************
```

</details>
mandlebug pushed a commit that referenced this pull request Feb 23, 2026
…er. (llvm#181941)

The progress event reporter has a thread that reports events every 250
millisecond. and is destroyed in its destructor.

When in event reporter desctructor, the event reporter may have pending
event but the call mutex is destroyed leading to the crash.

Relevant stack trace from CI.
```
[2026-02-13T17:46:13.577Z] libc++abi: terminating due to uncaught exception of type std::__1::system_error: mutex lock failed: Invalid argument 
[2026-02-13T17:46:13.577Z] PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash report from ~/Library/Logs/DiagnosticReports/. 

[2026-02-13T17:46:13.577Z]  #0 0x0000000102b6943c llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake-os-verficiation/lldb-build/bin/lldb-dap+0x10008943c) 
[2026-02-13T17:46:13.577Z]  #1 0x0000000102b67368 llvm::sys::RunSignalHandlers() (/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake-os-verficiation/lldb-build/bin/lldb-dap+0x100087368) 
[2026-02-13T17:46:13.577Z]  llvm#2 0x0000000102b69f20 SignalHandler(int, __siginfo*, void*) (/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake-os-verficiation/lldb-build/bin/lldb-dap+0x100089f20)
[2026-02-13T17:46:13.577Z]  llvm#3 0x000000018bbdb744 (/usr/lib/system/libsystem_platform.dylib+0x1804e3744) 
[2026-02-13T17:46:13.577Z]  llvm#4 0x000000018bbd1888 (/usr/lib/system/libsystem_pthread.dylib+0x1804d9888) 
[2026-02-13T17:46:13.577Z]  llvm#5 0x000000018bad6850 (/usr/lib/system/libsystem_c.dylib+0x1803de850) 
[2026-02-13T17:46:13.577Z]  llvm#6 0x000000018bb85858 (/usr/lib/libc++abi.dylib+0x18048d858) 
[2026-02-13T17:46:13.577Z]  llvm#7 0x000000018bb744bc (/usr/lib/libc++abi.dylib+0x18047c4bc) 
[2026-02-13T17:46:13.577Z]  llvm#8 0x000000018b7a0424 (/usr/lib/libobjc.A.dylib+0x1800a8424) 
[2026-02-13T17:46:13.577Z]  llvm#9 0x000000018bb84c2c (/usr/lib/libc++abi.dylib+0x18048cc2c) 
[2026-02-13T17:46:13.577Z] llvm#10 0x000000018bb88394 (/usr/lib/libc++abi.dylib+0x180490394) 
[2026-02-13T17:46:13.577Z] llvm#11 0x000000018bb8833c (/usr/lib/libc++abi.dylib+0x18049033c) 
[2026-02-13T17:46:13.577Z] llvm#12 0x000000018bb01b90 (/usr/lib/libc++.1.dylib+0x180409b90) 
[2026-02-13T17:46:13.577Z] llvm#13 0x000000018bb01b34 (/usr/lib/libc++.1.dylib+0x180409b34) 
[2026-02-13T17:46:13.577Z] llvm#14 0x000000018bb038a0 (/usr/lib/libc++.1.dylib+0x18040b8a0) 
[2026-02-13T17:46:13.577Z] llvm#15 0x0000000102b6fbac lldb_dap::DAP::Send(std::__1::variant<lldb_dap::protocol::Request, lldb_dap::protocol::Response, lldb_dap::protocol::Event> const&) (/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake-os-verficiation/lldb-build/bin/lldb-dap+0x10008fbac) 
[2026-02-13T17:46:13.577Z] llvm#16 0x0000000102b6f890 lldb_dap::DAP::SendJSON(llvm::json::Value const&) (/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake-os-verficiation/lldb-build/bin/lldb-dap+0x10008f890) 
[2026-02-13T17:46:13.577Z] llvm#17 0x0000000102b78788 std::__1::__function::__func<lldb_dap::DAP::DAP(lldb_dap::Log&, lldb_dap::ReplMode, std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>>, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>>>>, bool, llvm::StringRef, lldb_private::transport::JSONTransport<lldb_dap::ProtocolDescriptor>&, lldb_private::MainLoopPosix&)::$_0, std::__1::allocator<lldb_dap::DAP::DAP(lldb_dap::Log&, lldb_dap::ReplMode, std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>>, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>>>>, bool, llvm::StringRef, lldb_private::transport::JSONTransport<lldb_dap::ProtocolDescriptor>&, lldb_private::MainLoopPosix&)::$_0>, void (lldb_dap::ProgressEvent&)>::operator()(lldb_dap::ProgressEvent&) (/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake-os-verficiation/lldb-build/bin/lldb-dap+0x100098788) 
[2026-02-13T17:46:13.577Z] llvm#18 0x0000000102b8939c lldb_dap::ProgressEventManager::ReportIfNeeded() (/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake-os-verficiation/lldb-build/bin/lldb-dap+0x1000a939c) 
[2026-02-13T17:46:13.577Z] llvm#19 0x0000000102b8982c lldb_dap::ProgressEventReporter::ReportStartEvents() (/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake-os-verficiation/lldb-build/bin/lldb-dap+0x1000a982c) 
[2026-02-13T17:46:13.577Z] llvm#20 0x0000000102b8a038 void* std::__1::__thread_proxy[abi:nn200100]<std::__1::tuple<std::__1::unique_ptr<std::__1::__thread_struct, std::__1::default_delete<std::__1::__thread_struct>>, lldb_dap::ProgressEventReporter::ProgressEventReporter(std::__1::function<void (lldb_dap::ProgressEvent&)>)::$_0>>(void*) (/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake-os-verficiation/lldb-build/bin/lldb-dap+0x1000aa038) 
[2026-02-13T17:46:13.577Z] llvm#21 0x000000018bbd1c08 (/usr/lib/system/libsystem_pthread.dylib+0x1804d9c08) [2026-02-13T17:46:13.577Z] llvm#22 0x000000018bbccba8 (/usr/lib/system/libsystem_pthread.dylib+0x1804d4ba8)
```
rdar://170331108
mandlebug pushed a commit that referenced this pull request Feb 23, 2026
I created an issue about this in llvm#179976.

Clang's Address Sanitizer installs its own SEH filter which handles some
types of uncaught exceptions. Along with register values and some other
information, it also generates a stack trace. However, current logic is
incomplete. It relies on DbgHelp's SymFunctionTableAccess64 and
SymGetModuleBase64 which won't work with machine code that has its
RUNTIME_FUNCTION entry registered with Rtl* (e.g. RtlAddFunctionTable)
system calls. Most likely, this is because DbgHelp either relies on
information in PDB files or considers PDATA and XDATA only from loaded
EXE and DLL modules. Either way, consider the following example:

```
#include <windows.h>
#include <iostream>
#include <vector>

typedef union _UNWIND_CODE {
    struct {
        BYTE CodeOffset;
        BYTE UnwindOp : 4;
        BYTE OpInfo : 4;
    };
    USHORT FrameOffset;
} UNWIND_CODE, * PUNWIND_CODE;

typedef struct _UNWIND_INFO {
    BYTE Version : 3;
    BYTE Flags : 5;
    BYTE SizeOfProlog;
    BYTE CountOfCodes;
    BYTE FrameRegister : 4;
    BYTE FrameOffset : 4;
    UNWIND_CODE UnwindCode[1]; // Variable size
} UNWIND_INFO, * PUNWIND_INFO;

#define UWOP_PUSH_NONVOL      0
#define UWOP_ALLOC_LARGE      1
#define UWOP_ALLOC_SMALL      2
#define UWOP_SET_FPREG        3
#define UWOP_SAVE_NONVOL      4
#define UWOP_SAVE_NONVOL_FAR  5
#define UWOP_SAVE_XMM128      8
#define UWOP_SAVE_XMM128_FAR  9
#define UWOP_PUSH_MACHFRAME   10

int main() {
    // PUSH RBX         (0x53)                - Save non-volatile register
    // SUB RSP, 0x20    (0x48 0x83 0xEC 0x20) - Allocate 32 bytes (shadow space)
    // XOR RAX, RAX     (0x48 0x31 0xC0)      - Zero out RAX
    // MOV RAX, [RAX]   (0x48 0x8B 0x00)      - Dereference NULL
    
    std::vector<unsigned char> code = {
        0x53,
        0x48, 0x83, 0xEC, 0x20,
        0x48, 0x31, 0xC0,
        0x48, 0x8B, 0x00
    };

    size_t codeSize = code.size();
    size_t totalSize = 100;

    LPVOID pMemory = VirtualAlloc(NULL, totalSize, MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE);
    
    BYTE* pCodeBase = (BYTE*)pMemory;
    PUNWIND_INFO pUnwindInfo = (PUNWIND_INFO)(pCodeBase + codeSize);    

    size_t alignmentPadding = 0;
    if ((size_t)pUnwindInfo % 4 != 0) {
        alignmentPadding = 4 - ((size_t)pUnwindInfo % 4);
        pUnwindInfo = (PUNWIND_INFO)((BYTE*)pUnwindInfo + alignmentPadding);
    }

    memcpy(pCodeBase, code.data(), codeSize);

    pUnwindInfo->Version = 1;
    pUnwindInfo->Flags = UNW_FLAG_NHANDLER;
    pUnwindInfo->Flags = 0; 
    pUnwindInfo->SizeOfProlog = 5; 
    pUnwindInfo->CountOfCodes = 2; 
    pUnwindInfo->FrameRegister = 0;
    pUnwindInfo->FrameOffset = 0;

    pUnwindInfo->UnwindCode[0].CodeOffset = 5;
    pUnwindInfo->UnwindCode[0].UnwindOp = UWOP_ALLOC_SMALL;
    pUnwindInfo->UnwindCode[0].OpInfo = 3; 

    pUnwindInfo->UnwindCode[1].CodeOffset = 1;
    pUnwindInfo->UnwindCode[1].UnwindOp = UWOP_PUSH_NONVOL;
    pUnwindInfo->UnwindCode[1].OpInfo = 3; // RBX

    RUNTIME_FUNCTION tableEntry = {};
    tableEntry.BeginAddress = 0;
    tableEntry.EndAddress = (DWORD)codeSize;
    tableEntry.UnwindData = (DWORD)((BYTE*)pUnwindInfo - (BYTE*)pMemory);

    DWORD64 baseAddress = (DWORD64)pMemory;
    RtlAddFunctionTable(&tableEntry, 1, baseAddress);

    typedef void(*FuncType)();
    FuncType myFunc = (FuncType)pMemory;
    myFunc();

    return 0;
}
```

Windows' kernel can propagate hardware exception through that function,
so clearly these entries are at least partially correct. Right now,
ASan's stack walking produces this (compiled with latest release,
clang++):

```
PS D:\Local Projects\cpp-playground> ./a.exe
=================================================================
==14216==ERROR: AddressSanitizer: access-violation on unknown address 0x000000000000 (pc 0x0199561c0008 bp 0x004cf0cffb30 sp 0x004cf0cff970 T0)
==14216==The signal is caused by a READ memory access.
==14216==Hint: address points to the zero page.
    #0 0x0199561c0007  (<unknown module>)
    #1 0x000000000000  (<unknown module>)
    llvm#2 0x000000000000  (<unknown module>)

==14216==Register values:
rax = 0  rbx = 4cf0cffaa0  rcx = 7ffcb97b4e28  rdx = 19955dc0000
rdi = 11bf564a0040  rsi = 0  rbp = 4cf0cffb30  rsp = 4cf0cff970
r8  = 7ffffffffffffffc  r9  = 1  r10 = 0  r11 = 246
r12 = 0  r13 = 0  r14 = 0  r15 = 0
AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: access-violation (<unknown module>)
==14216==ABORTING
```

Frames one and two is just some stack space allocated by that dynamic
function. While patched version produces this:

```
PS D:\Local Projects\cpp-playground> ./a.exe
=================================================================
==13660==ERROR: AddressSanitizer: access-violation on unknown address 0x000000000000 (pc 0x01ed5ad70008 bp 0x00d76492f650 sp 0x00d76492f490 T0)
==13660==The signal is caused by a READ memory access.
==13660==Hint: address points to the zero page.
    #0 0x01ed5ad70007  (<unknown module>)
    #1 0x7ff732e518a1 in main (D:\Local Projects\cpp-playground\a.exe+0x1400018a1)
    llvm#2 0x7ff732e56a9b in invoke_main D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:78
    llvm#3 0x7ff732e56a9b in __scrt_common_main_seh D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288
    llvm#4 0x7ffcb878e8d6  (C:\WINDOWS\System32\KERNEL32.DLL+0x18002e8d6)
    llvm#5 0x7ffcb966c53b  (C:\WINDOWS\SYSTEM32\ntdll.dll+0x18008c53b)

==13660==Register values:
rax = 0  rbx = d76492f5c0  rcx = 7ffcb97b4e28  rdx = 1ed5a870000
rdi = 12135afa0040  rsi = 0  rbp = d76492f650  rsp = d76492f490
r8  = 7ffffffffffffffc  r9  = 1  r10 = 0  r11 = 246
r12 = 0  r13 = 0  r14 = 0  r15 = 0
AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: access-violation (<unknown module>)
==13660==ABORTING
```

Now we see that stack walking handled our dynamic function properly.
Interestingly enough, it appears that other overloaded version of
UnwindSlow procedure that works without CONTEXT structure already has
some logic to handle this. Theoretically, symbolizer should also be able
to provide some information about these functions, but I don't think
that this is necessary.

I added SANITIZER_WINDOWS64 check because I am pretty sure Microsoft
only mentions these functions for 64 bit version of their OS. I also
can't check how this works on ARM.
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