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[DTLTO] Normalize Windows 8.3 short paths to long form #4

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bd1976bris wants to merge 20 commits into
dtlto_elf_lldfrom
dtlto_normalize_paths
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[DTLTO] Normalize Windows 8.3 short paths to long form #4
bd1976bris wants to merge 20 commits into
dtlto_elf_lldfrom
dtlto_normalize_paths

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@bd1976bris bd1976bris commented Jun 17, 2025

8.3-style short-form paths (e.g., C:\PROGRA~1) can cause inconsistencies or
failures on remote machines during distributed linking. Such paths may not
resolve correctly or may differ between systems. Short-form paths are
relatively common - for example, clang often writes temporary object files
to %TEMP%, which is frequently a short-form path.

We are aware of at least one distribution system (SN-DBS) affected by this,
and we expect that many (perhaps all) distribution systems may encounter
similar issues.

This patch ensures that all Windows paths used for DTLTO in ELF LLD are
normalized to their long form using GetLongPathNameW. This avoids ambiguity
and improves portability across distribution environments.

For testing, AreShortNamesEnabled is used to detect whether 8.3 path support
is enabled on the current volume. However, this API is only available on
Windows 11. As a result, the related tests are skipped on earlier versions
of Windows due to the lack of a reliable alternative for feature detection.

This patch introduces support for Integrated Distributed ThinLTO
(DTLTO) in ELF LLD.

DTLTO enables the distribution of ThinLTO backend compilations via
external distribution systems, such as Incredibuild, during the
traditional link step: https://llvm.org/docs/DTLTO.html.

It is expected that users will invoke DTLTO through the compiler
driver (e.g., Clang) rather than calling LLD directly. A Clang-side
interface for DTLTO will be added in a follow-up patch.

Note: Bitcode members of non-thin archives are not currently
supported. This will be addressed in a future change.

Testing:
- ELF LLD `lit` test coverage has been added, using a mock distributor
  to avoid requiring Clang.
- Cross-project `lit` tests cover integration with Clang.

For the design discussion of the DTLTO feature, see:
llvm#126654
8.3-style short paths (e.g., C:\PROGRA~1) can cause inconsistencies or
failures on remote machines during distributed linking. Such paths may
not resolve correctly or may differ between systems. We anticipate
that many/all distribution systems will have difficulties with such
paths.

This patch ensures that all Windows paths used for DTLTO in ELF LLD are
converted to their long form using GetLongPathNameW. This avoids
ambiguity and improves portability across most distribution systems.
@bd1976bris bd1976bris force-pushed the dtlto_normalize_paths branch from 2011c8c to d24e531 Compare June 17, 2025 11:58
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I have left some comments/questions.

In the commit comment, it says "We anticipate that many/all distribution systems will have difficulties with such paths". That's true, but we can additionally concretely say we know of at least one such system.

I think it's also worth saying that the occurrence of short form paths is quite common. One notable example is clang writing (temporary) objects to %TEMP%, which can be in short form.

Comment thread lld/ELF/InputFiles.cpp Outdated
Comment thread llvm/include/llvm/Support/Windows/WindowsSupport.h Outdated
Comment thread llvm/lib/Support/Windows/Path.inc
Comment thread llvm/unittests/Support/Path.cpp Outdated
Comment thread llvm/unittests/Support/Path.cpp Outdated
Comment on lines +2495 to +2496
if (!getFullPath(Path16, FullPath16))
return false;
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Can we instead use make_absolute while the path is still narrow? Then getFullPath() can be removed.

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Yes. Nice comment thanks very much. Inspired by this I tried using root_path and was able to get that to work. So we can drop the Win32 API wrappers for getting the full path and for getting the volume. We don't even need make_absoute because as this is test code we can simply guarantee that the incoming path is absolute.

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The python in the LIT config has been simplified in the same manner.

Comment thread cross-project-tests/dtlto/path.test Outdated
Comment thread cross-project-tests/dtlto/path.test Outdated
Comment thread cross-project-tests/dtlto/path.test Outdated
Comment on lines +48 to +49
# Copy the CWD to a unique directory inside TEMP and determine its 8.3 form.
# TEMP is likely to be on a drive that supports long+short paths.
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This isn't guaranteed. So we ought to handle the case where short paths are not enabled.

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Yes. In fact I feel like this was addressed already and I have just dropped a commit somewhere along the line..

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Done now. I have used ctypes and python to query Win32s AreShortPathsEnabled function if it is available in the lit config for the cross-project tests.

Comment thread cross-project-tests/dtlto/path.test Outdated
Comment thread cross-project-tests/dtlto/path.test Outdated
bd1976bris and others added 9 commits June 17, 2025 14:42
Co-authored-by: Edd Dawson <edd.dawson@sony.com>
Co-authored-by: Edd Dawson <edd.dawson@sony.com>
Co-authored-by: Edd Dawson <edd.dawson@sony.com>
Co-authored-by: Edd Dawson <edd.dawson@sony.com>
Co-authored-by: Edd Dawson <edd.dawson@sony.com>
Co-authored-by: Edd Dawson <edd.dawson@sony.com>
The cross-project `path.test` assumes that the Windows volume for the
%TEMP% directories has short paths enabled, this is not guaranteed.
This change allows tests cross-project-tests to `REQUIRE: shortpaths`
and `path.test` test uses this feature.
@bd1976bris
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I have left some comments/questions.

In the commit comment, it says "We anticipate that many/all distribution systems will have difficulties with such paths". That's true, but we can additionally concretely say we know of at least one such system.

I think it's also worth saying that the occurrence of short form paths is quite common. One notable example is clang writing (temporary) objects to %TEMP%, which can be in short form.

Great points. I have updated the description of this PR to include those points and will use that description when I squash the commits here to create a single commit for LLVM side review.

…W rather than guessing the 8.3 short-form name
…ed. I wasn't able to figure out how to test this without admin permissions for the tests. Therefore, I'm not going to try to add automated tests for this.
…s expected. I wasn't able to figure out how to test this without admin permissions for the tests. Therefore, I'm not going to try to add automated tests for this."

This reverts commit 7227c20.
Also:
- Formatted all python with "black"
- Minor test comment, naming and structure improvements.
bd1976bris pushed a commit that referenced this pull request Jul 2, 2025
The function already exposes a work list to avoid deep recursion, this
commit starts utilizing it in a helper that could also lead to a deep
recursion.

We have observed this crash on `clang/test/C/C99/n590.c` with our
internal builds that enable aggressive optimizations and hit the limit
earlier than default release builds of Clang.

See the added test for an example with a deeper recursion that used to
crash in upstream Clang before this change with the following stack
trace:

```
  #0 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /usr/local/google/home/ibiryukov/code/llvm-project/llvm/lib/Support/Unix/Signals.inc:804:13
  #1 llvm::sys::RunSignalHandlers() /usr/local/google/home/ibiryukov/code/llvm-project/llvm/lib/Support/Signals.cpp:106:18
  #2 SignalHandler(int, siginfo_t*, void*) /usr/local/google/home/ibiryukov/code/llvm-project/llvm/lib/Support/Unix/Signals.inc:0:3
  #3 (/lib/x86_64-linux-gnu/libc.so.6+0x3fdf0)
  #4 AnalyzeImplicitConversions(clang::Sema&, clang::Expr*, clang::SourceLocation, bool) /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:12772:0
  llvm#5 CheckCommaOperand /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:0:3
  llvm#6 AnalyzeImplicitConversions /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:12644:7
  llvm#7 AnalyzeImplicitConversions(clang::Sema&, clang::Expr*, clang::SourceLocation, bool) /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:12776:5
  llvm#8 CheckCommaOperand /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:0:3
  llvm#9 AnalyzeImplicitConversions /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:12644:7
 llvm#10 AnalyzeImplicitConversions(clang::Sema&, clang::Expr*, clang::SourceLocation, bool) /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:12776:5
 llvm#11 CheckCommaOperand /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:0:3
 llvm#12 AnalyzeImplicitConversions /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:12644:7
 llvm#13 AnalyzeImplicitConversions(clang::Sema&, clang::Expr*, clang::SourceLocation, bool) /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:12776:5
 llvm#14 CheckCommaOperand /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:0:3
 llvm#15 AnalyzeImplicitConversions /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:12644:7
 llvm#16 AnalyzeImplicitConversions(clang::Sema&, clang::Expr*, clang::SourceLocation, bool) /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:12776:5
 llvm#17 CheckCommaOperand /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:0:3
 llvm#18 AnalyzeImplicitConversions /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:12644:7
 llvm#19 AnalyzeImplicitConversions(clang::Sema&, clang::Expr*, clang::SourceLocation, bool) /usr/local/google/home/ibiryukov/code/llvm-project/clang/lib/Sema/SemaChecking.cpp:12776:5
... 700+ more stack frames.
```
bd1976bris pushed a commit that referenced this pull request Nov 27, 2025
…am (llvm#167724)

This got exposed by `09262656f32ab3f2e1d82e5342ba37eecac52522`.

The underlying stream of `m_os` is referenced by the `TextDiagnostic`
member of `TextDiagnosticPrinter`. It got turned into a
`llvm::formatted_raw_ostream` in the commit above. When
`~TextDiagnosticPrinter` (and thus `~TextDiagnostic`) is invoked, we now
call `~formatted_raw_ostream`, which tries to access the underlying
stream. But `m_os` was already deleted because it is earlier in the
order of destruction in `TextDiagnosticPrinter`. Move the `m_os` member
before the `TextDiagnosticPrinter` to avoid a use-after-free.

Drive-by:
* Also move the `m_output` member which the `m_os` holds a reference to.
The fact it's a reference indicates the expectation is most likely that
the string outlives the stream.

The ASAN macOS bot is currently failing with this:
```
08:15:39  =================================================================
08:15:39  ==61103==ERROR: AddressSanitizer: heap-use-after-free on address 0x60600012cf40 at pc 0x00012140d304 bp 0x00016eecc850 sp 0x00016eecc848
08:15:39  READ of size 8 at 0x60600012cf40 thread T0
08:15:39      #0 0x00012140d300 in llvm::formatted_raw_ostream::releaseStream() FormattedStream.h:205
08:15:39      #1 0x00012140d3a4 in llvm::formatted_raw_ostream::~formatted_raw_ostream() FormattedStream.h:145
08:15:39      #2 0x00012604abf8 in clang::TextDiagnostic::~TextDiagnostic() TextDiagnostic.cpp:721
08:15:39      #3 0x00012605dc80 in clang::TextDiagnosticPrinter::~TextDiagnosticPrinter() TextDiagnosticPrinter.cpp:30
08:15:39      #4 0x00012605dd5c in clang::TextDiagnosticPrinter::~TextDiagnosticPrinter() TextDiagnosticPrinter.cpp:27
08:15:39      llvm#5 0x0001231fb210 in (anonymous namespace)::StoringDiagnosticConsumer::~StoringDiagnosticConsumer() ClangModulesDeclVendor.cpp:47
08:15:39      llvm#6 0x0001231fb3bc in (anonymous namespace)::StoringDiagnosticConsumer::~StoringDiagnosticConsumer() ClangModulesDeclVendor.cpp:47
08:15:39      llvm#7 0x000129aa9d70 in clang::DiagnosticsEngine::~DiagnosticsEngine() Diagnostic.cpp:91
08:15:39      llvm#8 0x0001230436b8 in llvm::RefCountedBase<clang::DiagnosticsEngine>::Release() const IntrusiveRefCntPtr.h:103
08:15:39      llvm#9 0x0001231fe6c8 in (anonymous namespace)::ClangModulesDeclVendorImpl::~ClangModulesDeclVendorImpl() ClangModulesDeclVendor.cpp:93
08:15:39      llvm#10 0x0001231fe858 in (anonymous namespace)::ClangModulesDeclVendorImpl::~ClangModulesDeclVendorImpl() ClangModulesDeclVendor.cpp:93
...
08:15:39
08:15:39  0x60600012cf40 is located 32 bytes inside of 56-byte region [0x60600012cf20,0x60600012cf58)
08:15:39  freed by thread T0 here:
08:15:39      #0 0x0001018abb88 in _ZdlPv+0x74 (libclang_rt.asan_osx_dynamic.dylib:arm64e+0x4bb88)
08:15:39      #1 0x0001231fb1c0 in (anonymous namespace)::StoringDiagnosticConsumer::~StoringDiagnosticConsumer() ClangModulesDeclVendor.cpp:47
08:15:39      #2 0x0001231fb3bc in (anonymous namespace)::StoringDiagnosticConsumer::~StoringDiagnosticConsumer() ClangModulesDeclVendor.cpp:47
08:15:39      #3 0x000129aa9d70 in clang::DiagnosticsEngine::~DiagnosticsEngine() Diagnostic.cpp:91
08:15:39      #4 0x0001230436b8 in llvm::RefCountedBase<clang::DiagnosticsEngine>::Release() const IntrusiveRefCntPtr.h:103
08:15:39      llvm#5 0x0001231fe6c8 in (anonymous namespace)::ClangModulesDeclVendorImpl::~ClangModulesDeclVendorImpl() ClangModulesDeclVendor.cpp:93
08:15:39      llvm#6 0x0001231fe858 in (anonymous namespace)::ClangModulesDeclVendorImpl::~ClangModulesDeclVendorImpl() ClangModulesDeclVendor.cpp:93
...
08:15:39
08:15:39  previously allocated by thread T0 here:
08:15:39      #0 0x0001018ab760 in _Znwm+0x74 (libclang_rt.asan_osx_dynamic.dylib:arm64e+0x4b760)
08:15:39      #1 0x0001231f8dec in lldb_private::ClangModulesDeclVendor::Create(lldb_private::Target&) ClangModulesDeclVendor.cpp:732
08:15:39      #2 0x00012320af58 in lldb_private::ClangPersistentVariables::GetClangModulesDeclVendor() ClangPersistentVariables.cpp:124
08:15:39      #3 0x0001232111f0 in lldb_private::ClangUserExpression::PrepareForParsing(lldb_private::DiagnosticManager&, lldb_private::ExecutionContext&, bool) ClangUserExpression.cpp:536
08:15:39      #4 0x000123213790 in lldb_private::ClangUserExpression::Parse(lldb_private::DiagnosticManager&, lldb_private::ExecutionContext&, lldb_private::ExecutionPolicy, bool, bool) ClangUserExpression.cpp:647
08:15:39      llvm#5 0x00012032b258 in lldb_private::UserExpression::Evaluate(lldb_private::ExecutionContext&, lldb_private::EvaluateExpressionOptions const&, llvm::StringRef, llvm::StringRef, std::__1::shared_ptr<lldb_private::ValueObject>&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>>*, lldb_private::ValueObject*) UserExpression.cpp:280
08:15:39      llvm#6 0x000120724010 in lldb_private::Target::EvaluateExpression(llvm::StringRef, lldb_private::ExecutionContextScope*, std::__1::shared_ptr<lldb_private::ValueObject>&, lldb_private::EvaluateExpressionOptions const&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>>*, lldb_private::ValueObject*) Target.cpp:2905
08:15:39      llvm#7 0x00011fc7bde0 in lldb::SBTarget::EvaluateExpression(char const*, lldb::SBExpressionOptions const&) SBTarget.cpp:2305
08:15:39  ==61103==ABORTING
...
```
bd1976bris pushed a commit that referenced this pull request Jan 6, 2026
…lvm#159480)

When building rustc std for arm64e, core fails to compile successfully
with the error:
```
Constant ValueID not recognized.
UNREACHABLE executed at rust/src/llvm-project/llvm/lib/Transforms/Utils/FunctionComparator.cpp:523!
```

This is a result of function merging so I modified
FunctionComparator.cpp as the ConstantPtrAuth value would go unchecked
in the switch statement.

The test case is a reduction from the failure in core and fails on main
with:
```
********************
FAIL: LLVM :: Transforms/MergeFunc/ptrauth-const-compare.ll (59809 of 59995)
******************** TEST 'LLVM :: Transforms/MergeFunc/ptrauth-const-compare.ll' FAILED ********************
Exit Code: 2

Command Output (stdout):
--
# RUN: at line 3
/Users/oskarwirga/llvm-project/build/bin/opt -S -passes=mergefunc < /Users/oskarwirga/llvm-project/llvm/test/Transforms/MergeFunc/ptrauth-const-compare.ll | /Users/oskarwirga/llvm-project/build/bin/FileCheck /Users/oskarwirga/llvm-project/llvm/test/Transforms/MergeFunc/ptrauth-const-compare.ll
# executed command: /Users/oskarwirga/llvm-project/build/bin/opt -S -passes=mergefunc
# .---command stderr------------
# | Constant ValueID not recognized.
# | UNREACHABLE executed at /Users/oskarwirga/llvm-project/llvm/lib/Transforms/Utils/FunctionComparator.cpp:523!
# | PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace and instructions to reproduce the bug.
# | Stack dump:
# | 0.	Program arguments: /Users/oskarwirga/llvm-project/build/bin/opt -S -passes=mergefunc
# | 1.	Running pass "mergefunc" on module "<stdin>"
# |  #0 0x0000000103335770 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/Users/oskarwirga/llvm-project/build/bin/opt+0x102651770)
# |  #1 0x00000001033336bc llvm::sys::RunSignalHandlers() (/Users/oskarwirga/llvm-project/build/bin/opt+0x10264f6bc)
# |  #2 0x0000000103336218 SignalHandler(int, __siginfo*, void*) (/Users/oskarwirga/llvm-project/build/bin/opt+0x102652218)
# |  #3 0x000000018e6c16a4 (/usr/lib/system/libsystem_platform.dylib+0x1804ad6a4)
# |  #4 0x000000018e68788c (/usr/lib/system/libsystem_pthread.dylib+0x18047388c)
# |  llvm#5 0x000000018e590a3c (/usr/lib/system/libsystem_c.dylib+0x18037ca3c)
# |  llvm#6 0x00000001032a84bc llvm::install_out_of_memory_new_handler() (/Users/oskarwirga/llvm-project/build/bin/opt+0x1025c44bc)
# |  llvm#7 0x00000001033b37c0 llvm::FunctionComparator::cmpMDNode(llvm::MDNode const*, llvm::MDNode const*) const (/Users/oskarwirga/llvm-project/build/bin/opt+0x1026cf7c0)
# |  llvm#8 0x00000001033b4d90 llvm::FunctionComparator::cmpBasicBlocks(llvm::BasicBlock const*, llvm::BasicBlock const*) const (/Users/oskarwirga/llvm-project/build/bin/opt+0x1026d0d90)
# |  llvm#9 0x00000001033b5234 llvm::FunctionComparator::compare() (/Users/oskarwirga/llvm-project/build/bin/opt+0x1026d1234)
# | llvm#10 0x0000000102d6d868 (anonymous namespace)::MergeFunctions::insert(llvm::Function*) (/Users/oskarwirga/llvm-project/build/bin/opt+0x102089868)
# | llvm#11 0x0000000102d6bc0c llvm::MergeFunctionsPass::runOnModule(llvm::Module&) (/Users/oskarwirga/llvm-project/build/bin/opt+0x102087c0c)
# | llvm#12 0x0000000102d6b430 llvm::MergeFunctionsPass::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/Users/oskarwirga/llvm-project/build/bin/opt+0x102087430)
# | llvm#13 0x0000000102b90558 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/Users/oskarwirga/llvm-project/build/bin/opt+0x101eac558)
# | llvm#14 0x0000000103734bc4 llvm::runPassPipeline(llvm::StringRef, llvm::Module&, llvm::TargetMachine*, llvm::TargetLibraryInfoImpl*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::StringRef, llvm::ArrayRef<llvm::PassPlugin>, llvm::ArrayRef<std::__1::function<void (llvm::PassBuilder&)>>, llvm::opt_tool::OutputKind, llvm::opt_tool::VerifierKind, bool, bool, bool, bool, bool, bool, bool, bool) (/Users/oskarwirga/llvm-project/build/bin/opt+0x102a50bc4)
# | llvm#15 0x000000010373cc28 optMain (/Users/oskarwirga/llvm-project/build/bin/opt+0x102a58c28)
# | llvm#16 0x000000018e2e6b98
# `-----------------------------
# error: command failed with exit status: -6
# executed command: /Users/oskarwirga/llvm-project/build/bin/FileCheck /Users/oskarwirga/llvm-project/llvm/test/Transforms/MergeFunc/ptrauth-const-compare.ll
# .---command stderr------------
# | FileCheck error: '<stdin>' is empty.
# | FileCheck command line:  /Users/oskarwirga/llvm-project/build/bin/FileCheck /Users/oskarwirga/llvm-project/llvm/test/Transforms/MergeFunc/ptrauth-const-compare.ll
# `-----------------------------
# error: command failed with exit status: 2
```
bd1976bris pushed a commit that referenced this pull request Jan 6, 2026
CHR builds the merged hot-path predicate with
IRBuilder::CreateLogicalAnd. That helper is implemented as a select and
can constant-fold to a non- Instruction (e.g. i1 true). The pass then
attempted to mark the merged condition as having explicitly unknown
branch weights when profile data is present, but it unconditionally did
cast<Instruction>(MergedCondition), which can crash in release builds.

Guard the metadata update with dyn_cast<Instruction> and pass the
containing Function explicitly to avoid calling Instruction::getFunction
when the value is not attached yet.

Add a regression test that exercises the constant-folding case.

Crashing stack:

```
  2.      Running pass "chr" on function "repro_crash"
  #0 0x0000000003be00a4 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (bin/opt+0x3be00a4)
  #1 0x0000000003bdd9e8 llvm::sys::RunSignalHandlers() (bin/opt+0x3bdd9e8)
  #2 0x0000000003be1300 SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
  #3 0x0000ffffa8e1d840 (linux-vdso.so.1+0x840)
  #4 0x0000000003c815e0 llvm::Instruction::getFunction() const (bin/opt+0x3c815e0)
  llvm#5 0x0000000003dcd35c llvm::setExplicitlyUnknownBranchWeightsIfProfiled(llvm::Instruction&, llvm::StringRef, llvm::Function const*) (bin/opt+0x3dcd35c)
  llvm#6 0x0000000004fb3670 (anonymous namespace)::CHR::addToMergedCondition(bool, llvm::Value*, llvm::Instruction*, (anonymous namespace)::CHRScope*, llvm::IRBuilder<llvm::ConstantFolder, llvm::IRBuilderDefaultInserter>&, llvm::Value*&) ControlHeightReduction.cpp:0:0
  llvm#7 0x0000000004fa7d88 (anonymous namespace)::CHR::run() ControlHeightReduction.cpp:0:0
  llvm#8 0x0000000004fa3618 llvm::ControlHeightReductionPass::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (bin/opt+0x4fa3618)
```

Tests: opt <
llvm/test/Transforms/PGOProfile/chr-unknown-profdata-crash.ll
-passes='require<profile-summary>,function(chr)' -force-chr
-chr-merge-threshold=1 -disable-output
bd1976bris pushed a commit that referenced this pull request Jan 6, 2026
…ng destructor (llvm#174082)"

This reverts commit 7976ac9.

This is causing msan failures. msan-track-origins stack trace:

==9441==WARNING: MemorySanitizer: use-of-uninitialized-value
    #0 0x55c20df74ad3 in clang::interp::Pointer::operator=(clang::interp::Pointer&&) llvm-project/clang/lib/AST/ByteCode/Pointer.cpp:137:7
    #1 0x55c20db81010 in bool clang::interp::InitGlobal<(clang::interp::PrimType)13, clang::interp::Pointer>(clang::interp::InterpState&, clang::interp::CodePtr, unsigned int) llvm-project/clang/lib/AST/ByteCode/Interp.h:1478:16
    #2 0x55c20db7ec56 in emitInitGlobalPtr blaze-out/k8-fastbuild-msan/bin/llvm-project/clang/_virtual_includes/ast_bytecode_opcodes_gen/Opcodes.inc:26162:10
    #3 0x55c20db7ec56 in clang::interp::EvalEmitter::emitInitGlobal(clang::interp::PrimType, unsigned int, clang::interp::SourceInfo) blaze-out/k8-fastbuild-msan/bin/llvm-project/clang/_virtual_includes/ast_bytecode_opcodes_gen/Opcodes.inc:26042:12
    #4 0x55c20da58b87 in clang::interp::Compiler<clang::interp::EvalEmitter>::visitVarDecl(clang::VarDecl const*, clang::Expr const*, bool, bool) llvm-project/clang/lib/AST/ByteCode/Compiler.cpp:4924:20
    llvm#5 0x55c20da64a61 in clang::interp::Compiler<clang::interp::EvalEmitter>::visitDeclAndReturn(clang::VarDecl const*, clang::Expr const*, bool) llvm-project/clang/lib/AST/ByteCode/Compiler.cpp:4831:14
    llvm#6 0x55c20da7f290 in clang::interp::EvalEmitter::interpretDecl(clang::VarDecl const*, clang::Expr const*, bool) llvm-project/clang/lib/AST/ByteCode/EvalEmitter.cpp:66:14
    llvm#7 0x55c20d970d23 in clang::interp::Context::evaluateAsInitializer(clang::interp::State&, clang::VarDecl const*, clang::Expr const*, clang::APValue&) llvm-project/clang/lib/AST/ByteCode/Context.cpp:141:16
    llvm#8 0x55c20e25b8de in clang::Expr::EvaluateAsInitializer(clang::APValue&, clang::ASTContext const&, clang::VarDecl const*, llvm::SmallVectorImpl<std::__msan::pair<clang::SourceLocation, clang::PartialDiagnostic>>&, bool) const llvm-project/clang/lib/AST/ExprConstant.cpp:20754:20
    llvm#9 0x55c20da368d5 in clang::interp::Compiler<clang::interp::EvalEmitter>::visitDeclRef(clang::ValueDecl const*, clang::Expr const*) llvm-project/clang/lib/AST/ByteCode/Compiler.cpp:7162:19
    llvm#10 0x55c20da34986 in clang::interp::Compiler<clang::interp::EvalEmitter>::VisitDeclRefExpr(clang::DeclRefExpr const*) llvm-project/clang/lib/AST/ByteCode/Compiler.cpp:7192:16
    llvm#11 0x55c20da66666 in clang::StmtVisitorBase<llvm::make_const_ptr, clang::interp::Compiler<clang::interp::EvalEmitter>, bool>::Visit(clang::Stmt const*) blaze-out/k8-fastbuild-msan/bin/llvm-project/clang/include/clang/AST/StmtNodes.inc:474:1
    llvm#12 0x55c20da65d3f in clang::interp::Compiler<clang::interp::EvalEmitter>::visit(clang::Expr const*) llvm-project/clang/lib/AST/ByteCode/Compiler.cpp:4293:16
    llvm#13 0x55c20da57348 in clang::interp::Compiler<clang::interp::EvalEmitter>::VisitCXXTypeidExpr(clang::CXXTypeidExpr const*) llvm-project/clang/lib/AST/ByteCode/Compiler.cpp:3893:14
    llvm#14 0x55c20da66760 in clang::StmtVisitorBase<llvm::make_const_ptr, clang::interp::Compiler<clang::interp::EvalEmitter>, bool>::Visit(clang::Stmt const*) blaze-out/k8-fastbuild-msan/bin/llvm-project/clang/include/clang/AST/StmtNodes.inc:658:1
    llvm#15 0x55c20da65d3f in clang::interp::Compiler<clang::interp::EvalEmitter>::visit(clang::Expr const*) llvm-project/clang/lib/AST/ByteCode/Compiler.cpp:4293:16
    llvm#16 0x55c20da58afc in clang::interp::Compiler<clang::interp::EvalEmitter>::visitVarDecl(clang::VarDecl const*, clang::Expr const*, bool, bool) llvm-project/clang/lib/AST/ByteCode/Compiler.cpp:4921:18
    llvm#17 0x55c20da64a61 in clang::interp::Compiler<clang::interp::EvalEmitter>::visitDeclAndReturn(clang::VarDecl const*, clang::Expr const*, bool) llvm-project/clang/lib/AST/ByteCode/Compiler.cpp:4831:14
    llvm#18 0x55c20da7f290 in clang::interp::EvalEmitter::interpretDecl(clang::VarDecl const*, clang::Expr const*, bool) llvm-project/clang/lib/AST/ByteCode/EvalEmitter.cpp:66:14
    llvm#19 0x55c20d970d23 in clang::interp::Context::evaluateAsInitializer(clang::interp::State&, clang::VarDecl const*, clang::Expr const*, clang::APValue&) llvm-project/clang/lib/AST/ByteCode/Context.cpp:141:16
    llvm#20 0x55c20e25b8de in clang::Expr::EvaluateAsInitializer(clang::APValue&, clang::ASTContext const&, clang::VarDecl const*, llvm::SmallVectorImpl<std::__msan::pair<clang::SourceLocation, clang::PartialDiagnostic>>&, bool) const llvm-project/clang/lib/AST/ExprConstant.cpp:20754:20
    llvm#21 0x55c20dfdcc38 in clang::VarDecl::evaluateValueImpl(llvm::SmallVectorImpl<std::__msan::pair<clang::SourceLocation, clang::PartialDiagnostic>>&, bool) const llvm-project/clang/lib/AST/Decl.cpp:2608:23
    llvm#22 0x55c20dfdd1a2 in clang::VarDecl::checkForConstantInitialization(llvm::SmallVectorImpl<std::__msan::pair<clang::SourceLocation, clang::PartialDiagnostic>>&) const llvm-project/clang/lib/AST/Decl.cpp:2687:7
    llvm#23 0x55c20b9154da in clang::Sema::CheckCompleteVariableDeclaration(clang::VarDecl*) llvm-project/clang/lib/Sema/SemaDecl.cpp:14941:27
    llvm#24 0x55c20b910f36 in clang::Sema::AddInitializerToDecl(clang::Decl*, clang::Expr*, bool) llvm-project/clang/lib/Sema/SemaDecl.cpp:14280:3
    llvm#25 0x55c20ad044ee in clang::Parser::ParseDeclarationAfterDeclaratorAndAttributes(clang::Declarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::ForRangeInit*) llvm-project/clang/lib/Parse/ParseDecl.cpp:2639:17
    llvm#26 0x55c20acfe9f8 in clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::Parser::ParsedTemplateInfo&, clang::SourceLocation*, clang::Parser::ForRangeInit*) llvm-project/clang/lib/Parse/ParseDecl.cpp:2356:7
    llvm#27 0x55c20abd8a43 in clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) llvm-project/clang/lib/Parse/Parser.cpp:1181:10
    llvm#28 0x55c20abd7654 in clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) llvm-project/clang/lib/Parse/Parser.cpp:1203:12
    llvm#29 0x55c20abd4d9c in clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) llvm-project/clang/lib/Parse/Parser.cpp:1031:14
    llvm#30 0x55c20ac96f31 in clang::Parser::ParseInnerNamespace(llvm::SmallVector<clang::Parser::InnerNamespaceInfo, 4u> const&, unsigned int, clang::SourceLocation&, clang::ParsedAttributes&, clang::BalancedDelimiterTracker&) llvm-project/clang/lib/Parse/ParseDeclCXX.cpp:240:7
    llvm#31 0x55c20ac950c7 in clang::Parser::ParseNamespace(clang::DeclaratorContext, clang::SourceLocation&, clang::SourceLocation) llvm-project/clang/lib/Parse/ParseDeclCXX.cpp:218:3
    llvm#32 0x55c20acfb09b in clang::Parser::ParseDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::ParsedAttributes&, clang::SourceLocation*) llvm-project/clang/lib/Parse/ParseDecl.cpp:1909:12
    llvm#33 0x55c20abd3f88 in clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) llvm-project/clang/lib/Parse/Parser.cpp
    llvm#34 0x55c20abcfe33 in clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) llvm-project/clang/lib/Parse/Parser.cpp:744:12
    llvm#35 0x55c20abb214e in clang::ParseAST(clang::Sema&, bool, bool) llvm-project/clang/lib/Parse/ParseAST.cpp:170:20
    llvm#36 0x55c20a90adaa in clang::ASTFrontendAction::ExecuteAction() llvm-project/clang/lib/Frontend/FrontendAction.cpp:1432:3
    llvm#37 0x55c20a9095bf in clang::FrontendAction::Execute() llvm-project/clang/lib/Frontend/FrontendAction.cpp:1312:3
    llvm#38 0x55c20a76cdc7 in clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) llvm-project/clang/lib/Frontend/CompilerInstance.cpp:1004:33
    llvm#39 0x55c20805aab0 in clang::ExecuteCompilerInvocation(clang::CompilerInstance*) llvm-project/clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp:310:25
    llvm#40 0x55c20802e823 in cc1_main(llvm::ArrayRef<char const*>, char const*, void*) llvm-project/clang/tools/driver/cc1_main.cpp:304:15
    llvm#41 0x55c2080218ec in ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>) llvm-project/clang/tools/driver/driver.cpp:225:12
    llvm#42 0x55c20801ea91 in clang_main(int, char**, llvm::ToolContext const&) llvm-project/clang/tools/driver/driver.cpp:268:12
    llvm#43 0x55c20801a6af in main blaze-out/k8-fastbuild-msan/bin/llvm-project/clang/clang-driver.cpp:17:10
    llvm#44 0x7f79c4214351 in __libc_start_main (/usr/libc/lib64/libc.so.6+0x61351) (BuildId: ca23ec6d935352118622ce674a8bb52d)
    llvm#45 0x55c207f8c2e9 in _start /usr/libc/debug-src/src/csu/../sysdeps/x86_64/start.S:120

  Member fields were destroyed
    #0 0x55c207f9f5fd in __sanitizer_dtor_callback_fields llvm-project/compiler-rt/lib/msan/msan_interceptors.cpp:1074:5
    #1 0x55c20df74380 in ~Pointer llvm-project/clang/lib/AST/ByteCode/Pointer.h:826:12
    #2 0x55c20df74380 in clang::interp::Pointer::~Pointer() llvm-project/clang/lib/AST/ByteCode/Pointer.cpp:93:1
    #3 0x55c20da7c5ab in void dtorTy<clang::interp::Pointer>(clang::interp::Block*, std::byte*, clang::interp::Descriptor const*) llvm-project/clang/lib/AST/ByteCode/Descriptor.cpp:49:32
    #4 0x55c20d976b91 in clang::interp::Block::invokeDtor() llvm-project/clang/lib/AST/ByteCode/InterpBlock.h:149:7
    llvm#5 0x55c20da651a1 in clang::interp::Compiler<clang::interp::EvalEmitter>::visitDeclAndReturn(clang::VarDecl const*, clang::Expr const*, bool) llvm-project/clang/lib/AST/ByteCode/Compiler.cpp:4869:22
    llvm#6 0x55c20da7f290 in clang::interp::EvalEmitter::interpretDecl(clang::VarDecl const*, clang::Expr const*, bool) llvm-project/clang/lib/AST/ByteCode/EvalEmitter.cpp:66:14
    llvm#7 0x55c20d970d23 in clang::interp::Context::evaluateAsInitializer(clang::interp::State&, clang::VarDecl const*, clang::Expr const*, clang::APValue&) llvm-project/clang/lib/AST/ByteCode/Context.cpp:141:16
    llvm#8 0x55c20e25b8de in clang::Expr::EvaluateAsInitializer(clang::APValue&, clang::ASTContext const&, clang::VarDecl const*, llvm::SmallVectorImpl<std::__msan::pair<clang::SourceLocation, clang::PartialDiagnostic>>&, bool) const llvm-project/clang/lib/AST/ExprConstant.cpp:20754:20
    llvm#9 0x55c20dfdcc38 in clang::VarDecl::evaluateValueImpl(llvm::SmallVectorImpl<std::__msan::pair<clang::SourceLocation, clang::PartialDiagnostic>>&, bool) const llvm-project/clang/lib/AST/Decl.cpp:2608:23
    llvm#10 0x55c20dfdd1a2 in clang::VarDecl::checkForConstantInitialization(llvm::SmallVectorImpl<std::__msan::pair<clang::SourceLocation, clang::PartialDiagnostic>>&) const llvm-project/clang/lib/AST/Decl.cpp:2687:7
    llvm#11 0x55c20b9154da in clang::Sema::CheckCompleteVariableDeclaration(clang::VarDecl*) llvm-project/clang/lib/Sema/SemaDecl.cpp:14941:27
    llvm#12 0x55c20b910f36 in clang::Sema::AddInitializerToDecl(clang::Decl*, clang::Expr*, bool) llvm-project/clang/lib/Sema/SemaDecl.cpp:14280:3
    llvm#13 0x55c20ad044ee in clang::Parser::ParseDeclarationAfterDeclaratorAndAttributes(clang::Declarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::ForRangeInit*) llvm-project/clang/lib/Parse/ParseDecl.cpp:2639:17
    llvm#14 0x55c20acfe9f8 in clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::Parser::ParsedTemplateInfo&, clang::SourceLocation*, clang::Parser::ForRangeInit*) llvm-project/clang/lib/Parse/ParseDecl.cpp:2356:7
    llvm#15 0x55c20abd8a43 in clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) llvm-project/clang/lib/Parse/Parser.cpp:1181:10
    llvm#16 0x55c20abd7654 in clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) llvm-project/clang/lib/Parse/Parser.cpp:1203:12
    llvm#17 0x55c20abd4d9c in clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) llvm-project/clang/lib/Parse/Parser.cpp:1031:14
    llvm#18 0x55c20ac96f31 in clang::Parser::ParseInnerNamespace(llvm::SmallVector<clang::Parser::InnerNamespaceInfo, 4u> const&, unsigned int, clang::SourceLocation&, clang::ParsedAttributes&, clang::BalancedDelimiterTracker&) llvm-project/clang/lib/Parse/ParseDeclCXX.cpp:240:7
    llvm#19 0x55c20ac950c7 in clang::Parser::ParseNamespace(clang::DeclaratorContext, clang::SourceLocation&, clang::SourceLocation) llvm-project/clang/lib/Parse/ParseDeclCXX.cpp:218:3
    llvm#20 0x55c20acfb09b in clang::Parser::ParseDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::ParsedAttributes&, clang::SourceLocation*) llvm-project/clang/lib/Parse/ParseDecl.cpp:1909:12
bd1976bris pushed a commit that referenced this pull request Jan 19, 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
 #2 0x000055971cfcaf0c llvm::sys::CleanupOnSignal(unsigned long) /REDACTED//llvm-project/llvm/lib/Support/Unix/Signals.inc:0:3
 #3 0x000055971cf38116 (anonymous namespace)::CrashRecoveryContextImpl::HandleCrash(int, unsigned long) /REDACTED//llvm-project/llvm/lib/Support/CrashRecoveryContext.cpp:73:5
 #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>
bd1976bris pushed a commit that referenced this pull request Jan 27, 2026
This reverts commit 99fab01.

llc was crashing in kernel-args.ll after this patch:
```
.---command stderr------------
| LLVM ERROR: Cannot select: t3: f32,ch = load<(non-temporal dereferenceable invariant load (s16), align 4, addrspace 7), sext from f16> t0, Constant:i32<36>, undef:i32
| In function: f16_arg
| PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace and instructions to reproduce the bug.
| Stack dump:
| 0.	Program arguments: /b/ml-opt-devrel-x86-64-b1/build/bin/llc -mtriple=r600 -mcpu=redwood
| 1.	Running pass 'Function Pass Manager' on module '<stdin>'.
| 2.	Running pass 'Unnamed pass: implement Pass::getPassName()' on function '@f16_arg'
|  #0 0x0000561402607438 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/b/ml-opt-devrel-x86-64-b1/build/bin/llc+0x81a7438)
|  #1 0x0000561402604b75 llvm::sys::RunSignalHandlers() (/b/ml-opt-devrel-x86-64-b1/build/bin/llc+0x81a4b75)
|  #2 0x00005614026081b1 SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
|  #3 0x00007f55eb45a050 (/lib/x86_64-linux-gnu/libc.so.6+0x3c050)
|  #4 0x00007f55eb4a8eec (/lib/x86_64-linux-gnu/libc.so.6+0x8aeec)
|  llvm#5 0x00007f55eb459fb2 raise (/lib/x86_64-linux-gnu/libc.so.6+0x3bfb2)
|  llvm#6 0x00007f55eb444472 abort (/lib/x86_64-linux-gnu/libc.so.6+0x26472)
|  llvm#7 0x0000561402567005 llvm::report_fatal_error(llvm::Twine const&, bool) (/b/ml-opt-devrel-x86-64-b1/build/bin/llc+0x8107005)
|  llvm#8 0x00005614023e7ba7 llvm::SelectionDAGISel::CannotYetSelect(llvm::SDNode*) (/b/ml-opt-devrel-x86-64-b1/build/bin/llc+0x7f87ba7)
|  llvm#9 0x00005614023e6a7d llvm::SelectionDAGISel::SelectCodeCommon(llvm::SDNode*, unsigned char const*, unsigned int) (/b/ml-opt-devrel-x86-64-b1/build/bin/llc+0x7f86a7d)
| llvm#10 0x00005614023dae94 llvm::SelectionDAGISel::DoInstructionSelection() (/b/ml-opt-devrel-x86-64-b1/build/bin/llc+0x7f7ae94)
| llvm#11 0x00005614023d9e6a llvm::SelectionDAGISel::CodeGenAndEmitDAG() (/b/ml-opt-devrel-x86-64-b1/build/bin/llc+0x7f79e6a)
| llvm#12 0x00005614023d7b5e llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) (/b/ml-opt-devrel-x86-64-b1/build/bin/llc+0x7f77b5e)
| llvm#13 0x00005614023d4c30 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) (/b/ml-opt-devrel-x86-64-b1/build/bin/llc+0x7f74c30)
| llvm#14 0x00005614023d22e0 llvm::SelectionDAGISelLegacy::runOnMachineFunction(llvm::MachineFunction&) (/b/ml-opt-devrel-x86-64-b1/build/bin/llc+0x7f722e0)
| llvm#15 0x0000561401611793 llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (/b/ml-opt-devrel-x86-64-b1/build/bin/llc+0x71b1793)
| llvm#16 0x0000561401b790e5 llvm::FPPassManager::runOnFunction(llvm::Function&) (/b/ml-opt-devrel-x86-64-b1/build/bin/llc+0x77190e5)
| llvm#17 0x0000561401b80f72 llvm::FPPassManager::runOnModule(llvm::Module&) (/b/ml-opt-devrel-x86-64-b1/build/bin/llc+0x7720f72)
| llvm#18 0x0000561401b79b56 llvm::legacy::PassManagerImpl::run(llvm::Module&) (/b/ml-opt-devrel-x86-64-b1/build/bin/llc+0x7719b56)
| llvm#19 0x00005613ff4858f4 compileModule(char**, llvm::SmallVectorImpl<llvm::PassPlugin>&, llvm::LLVMContext&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>&) llc.cpp:0:0
| llvm#20 0x00005613ff482ed3 main (/b/ml-opt-devrel-x86-64-b1/build/bin/llc+0x5022ed3)
| llvm#21 0x00007f55eb44524a (/lib/x86_64-linux-gnu/libc.so.6+0x2724a)
| llvm#22 0x00007f55eb445305 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x27305)
| llvm#23 0x00005613ff47ea21 _start (/b/ml-opt-devrel-x86-64-b1/build/bin/llc+0x501ea21)
`-----------------------------
```
bd1976bris pushed a commit that referenced this pull request Feb 10, 2026
…lvm#178069)

Kernel panic is a special case, and there is no signal or exception for
that so we need to rely on special workaround called `dumptid`.
FreeBSDKernel plugin is supposed to find this thread and set it manually
through `SetStopInfo()` in `CalculateStopInfo()` like Mach core plugin
does.

Before (We had to find and select crashed thread list otherwise thread 1
was selected by default):
```
➜ sudo lldb /boot/panic/kernel -c /var/crash/vmcore.last
(lldb) target create "/boot/panic/kernel" --core "/var/crash/vmcore.last"
Core file '/var/crash/vmcore.last' (x86_64) was loaded.
(lldb) bt
* thread #1, name = '(pid 12991) dtrace'
  * frame #0: 0xffffffff80bf9322 kernel`sched_switch(td=0xfffff8015882f780, flags=259) at sched_ule.c:2448:26
    frame #1: 0xffffffff80bd38d2 kernel`mi_switch(flags=259) at kern_synch.c:530:2
    frame #2: 0xffffffff80c29799 kernel`sleepq_switch(wchan=0xfffff8014edff300, pri=0) at subr_sleepqueue.c:608:2
    frame #3: 0xffffffff80c29b76 kernel`sleepq_catch_signals(wchan=0xfffff8014edff300, pri=0) at subr_sleepqueue.c:523:3
    frame #4: 0xffffffff80c29d32 kernel`sleepq_timedwait_sig(wchan=<unavailable>, pri=<unavailable>) at subr_sleepqueue.c:704:11
    frame llvm#5: 0xffffffff80bd2e2d kernel`_sleep(ident=0xfffff8014edff300, lock=0xffffffff81df2880, priority=768, wmesg="uwait", sbt=2573804118162, pr=0, flags=512) at kern_synch.c:215:10
    frame llvm#6: 0xffffffff80be8622 kernel`umtxq_sleep(uq=0xfffff8014edff300, wmesg="uwait", timo=0xfffffe0279cb3d20) at kern_umtx.c:843:11
    frame llvm#7: 0xffffffff80bef87a kernel`do_wait(td=0xfffff8015882f780, addr=<unavailable>, id=0, timeout=0xfffffe0279cb3d90, compat32=1, is_private=1) at kern_umtx.c:1316:12
    frame llvm#8: 0xffffffff80bed264 kernel`__umtx_op_wait_uint_private(td=0xfffff8015882f780, uap=0xfffffe0279cb3dd8, ops=<unavailable>) at kern_umtx.c:3990:10
    frame llvm#9: 0xffffffff80beaabe kernel`sys__umtx_op [inlined] kern__umtx_op(td=<unavailable>, obj=<unavailable>, op=<unavailable>, val=<unavailable>, uaddr1=<unavailable>, uaddr2=<unavailable>, ops=<unavailable>) at kern_umtx.c:4999:10
    frame llvm#10: 0xffffffff80beaa89 kernel`sys__umtx_op(td=<unavailable>, uap=<unavailable>) at kern_umtx.c:5024:10
    frame llvm#11: 0xffffffff81122cd1 kernel`amd64_syscall [inlined] syscallenter(td=0xfffff8015882f780) at subr_syscall.c:165:11
    frame llvm#12: 0xffffffff81122c19 kernel`amd64_syscall(td=0xfffff8015882f780, traced=0) at trap.c:1208:2
    frame llvm#13: 0xffffffff810f1dbb kernel`fast_syscall_common at exception.S:570
```

After:
```
➜ sudo ./build/bin/lldb /boot/panic/kernel -c /var/crash/vmcore.last
(lldb) target create "/boot/panic/kernel" --core "/var/crash/vmcore.last"
Core file '/var/crash/vmcore.last' (x86_64) was loaded.
(lldb) bt
* thread llvm#18, name = '(pid 5409) powerd (crashed)', stop reason = kernel panic
  * frame #0: 0xffffffff80bc6c91 kernel`__curthread at pcpu_aux.h:57:2 [inlined]
    frame #1: 0xffffffff80bc6c91 kernel`doadump(textdump=0) at kern_shutdown.c:399:2
    frame #2: 0xffffffff804b3b7a kernel`db_dump(dummy=<unavailable>, dummy2=<unavailable>, dummy3=<unavailable>, dummy4=<unavailable>) at db_command.c:596:10
    frame #3: 0xffffffff804b396d kernel`db_command(last_cmdp=<unavailable>, cmd_table=<unavailable>, dopager=true) at db_command.c:508:3
    frame #4: 0xffffffff804b362d kernel`db_command_loop at db_command.c:555:3
    frame llvm#5: 0xffffffff804b7026 kernel`db_trap(type=<unavailable>, code=<unavailable>) at db_main.c:267:3
    frame llvm#6: 0xffffffff80c16aaf kernel`kdb_trap(type=3, code=0, tf=0xfffffe01b605b930) at subr_kdb.c:790:13
    frame llvm#7: 0xffffffff8112154e kernel`trap(frame=<unavailable>) at trap.c:614:8
    frame llvm#8: 0xffffffff810f14c8 kernel`calltrap at exception.S:285
    frame llvm#9: 0xffffffff81da2290 kernel`cn_devtab + 64
    frame llvm#10: 0xfffffe01b605b8b0
    frame llvm#11: 0xffffffff84001c43 dtrace.ko`dtrace_panic(format=<unavailable>) at dtrace.c:652:2
    frame llvm#12: 0xffffffff84005524 dtrace.ko`dtrace_action_panic(ecb=0xfffff80539cad580) at dtrace.c:7022:2 [inlined]
    frame llvm#13: 0xffffffff840054de dtrace.ko`dtrace_probe(id=88998, arg0=14343377283488, arg1=<unavailable>, arg2=<unavailable>, arg3=<unavailable>, arg4=<unavailable>) at dtrace.c:7665:6
    frame llvm#14: 0xffffffff83e5213d systrace.ko`systrace_probe(sa=<unavailable>, type=<unavailable>, retval=<unavailable>) at systrace.c:226:2
    frame llvm#15: 0xffffffff8112318d kernel`syscallenter(td=0xfffff801318d5780) at subr_syscall.c:160:4 [inlined]
    frame llvm#16: 0xffffffff81123112 kernel`amd64_syscall(td=0xfffff801318d5780, traced=0) at trap.c:1208:2
    frame llvm#17: 0xffffffff810f1dbb kernel`fast_syscall_common at exception.S:570
```
bd1976bris pushed a commit that referenced this pull request Feb 10, 2026
…8306)

In FreeBSD, allproc is a prepend list and new processes are appended at
head. This results in reverse pid order, so we first need to order pid
incrementally then print threads according to the correct order.

Before:
```
Process 0 stopped
* thread #1: tid = 101866, 0xffffffff80bf9322 kernel`sched_switch(td=0xfffff8015882f780, flags=259) at sched_ule.c:2448:26, name = '(pid 12991) dtrace'
  thread #2: tid = 101915, 0xffffffff80bf9322 kernel`sched_switch(td=0xfffff80158825780, flags=259) at sched_ule.c:2448:26, name = '(pid 11509) zsh'
  thread #3: tid = 101942, 0xffffffff80bf9322 kernel`sched_switch(td=0xfffff80142599000, flags=259) at sched_ule.c:2448:26, name = '(pid 11504) ftcleanup'
  thread #4: tid = 101545, 0xffffffff80bf9322 kernel`sched_switch(td=0xfffff80131898000, flags=259) at sched_ule.c:2448:26, name = '(pid 5599) zsh'
  thread llvm#5: tid = 100905, 0xffffffff80bf9322 kernel`sched_switch(td=0xfffff80131899000, flags=259) at sched_ule.c:2448:26, name = '(pid 5598) sshd-session'
  thread llvm#6: tid = 101693, 0xffffffff80bf9322 kernel`sched_switch(td=0xfffff8015886e780, flags=259) at sched_ule.c:2448:26, name = '(pid 5595) sshd-session'
  thread llvm#7: tid = 101626, 0xffffffff80bf9322 kernel`sched_switch(td=0xfffff801588be000, flags=259) at sched_ule.c:2448:26, name = '(pid 5592) sh'
...
```

After:
```
(lldb) thread list
Process 0 stopped
* thread #1: tid = 100000, 0xffffffff80bf9322 kernel`sched_switch(td=0xffffffff81abe840, flags=259) at sched_ule.c:2448:26, name = '(pid 0) kernel'
  thread #2: tid = 100035, 0xffffffff80bf9322 kernel`sched_switch(td=0xfffff801052d9780, flags=259) at sched_ule.c:2448:26, name = '(pid 0) kernel/softirq_0'
  thread #3: tid = 100036, 0xffffffff80bf9322 kernel`sched_switch(td=0xfffff801052d9000, flags=259) at sched_ule.c:2448:26, name = '(pid 0) kernel/softirq_1'
  thread #4: tid = 100037, 0xffffffff80bf9322 kernel`sched_switch(td=0xfffff801052d8780, flags=259) at sched_ule.c:2448:26, name = '(pid 0) kernel/softirq_2'
  thread llvm#5: tid = 100038, 0xffffffff80bf9322 kernel`sched_switch(td=0xfffff801052d8000, flags=259) at sched_ule.c:2448:26, name = '(pid 0) kernel/softirq_3'
  thread llvm#6: tid = 100039, 0xffffffff80bf9322 kernel`sched_switch(td=0xfffff801052d7780, flags=259) at sched_ule.c:2448:26, name = '(pid 0) kernel/softirq_4'
  thread llvm#7: tid = 100040, 0xffffffff80bf9322 kernel`sched_switch(td=0xfffff801052d7000, flags=259) at sched_ule.c:2448:26, name = '(pid 0) kernel/softirq_5'
...
```

Signed-off-by: Minsoo Choo <minsoochoo0122@proton.me>
bd1976bris pushed a commit that referenced this pull request Mar 27, 2026
…88255)

Expanded entrypoints.rst with details about definitions, registration
rules, and the lifecycle of an entrypoint.

Updated multiple documents to remove redundant technical details and
link to the centralized entrypoints reference:

- libc/docs/dev/cmake_build_rules.rst
- libc/docs/dev/implementation_standard.rst
- libc/docs/porting.rst
- libc/docs/dev/source_tree_layout.rst
bd1976bris pushed a commit that referenced this pull request Mar 27, 2026
…e edge case (llvm#188590)

llvm#186966 was reverted because
the test case triggered a use-of-uninitialized-memory
(https://lab.llvm.org/buildbot/#/builders/94/builds/16379), due to the
include directive omitting a trailing newline. This patch adds a minor
fix to avoid the use-of-uninitialized-memory, and deliberately re-adds
the test case sans trailing newline for regression testing.

MSan report prior to this fix:
```
@@@BUILD_STEP sanitizer logs: stage2/msan_track_origins check@@@
==clang-scan-deps==616960==WARNING: MemorySanitizer: use-of-uninitialized-value
    #0 0x5555599c3300 in isAnnotation /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/include/clang/Lex/Token.h:131:38
    #1 0x5555599c3300 in setLength /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/include/clang/Lex/Token.h:152:13
    #2 0x5555599c3300 in clang::Lexer::FormTokenWithChars(clang::Token&, char const*, clang::tok::TokenKind) /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/include/clang/Lex/Lexer.h:644:12
    #3 0x5555599cf895 in clang::Lexer::LexEndOfFile(clang::Token&, char const*) /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/lib/Lex/Lexer.cpp:3166:5
    #4 0x555559bb229b in clang::Preprocessor::Lex(clang::Token&) /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/lib/Lex/Preprocessor.cpp:916:11
    llvm#5 0x555559aa5365 in __invoke<void (clang::Preprocessor::*&)(clang::Token &), clang::Preprocessor *, clang::Token &> /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/libcxx_install_msan_track_origins/include/c++/v1/__type_traits/invoke.h:90:27
    llvm#6 0x555559aa5365 in invoke<void (clang::Preprocessor::*&)(clang::Token &), clang::Preprocessor *, clang::Token &> /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/libcxx_install_msan_track_origins/include/c++/v1/__functional/invoke.h:29:10
    llvm#7 0x555559aa5365 in operator()<void (clang::Preprocessor::*)(clang::Token &)> /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/lib/Lex/PPDirectives.cpp:470:5
    llvm#8 0x555559aa5365 in clang::Preprocessor::CheckEndOfDirective(llvm::StringRef, bool, llvm::SmallVectorImpl<clang::Token>*) /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/lib/Lex/PPDirectives.cpp:478:5
    llvm#9 0x555559ab96b5 in clang::Preprocessor::HandleIncludeDirective(clang::SourceLocation, clang::Token&, clang::detail::SearchDirIteratorImpl<true>, clang::FileEntry const*) /home/b/sanitizer-x86_64-linux-bootstrap-msan/build/llvm-project/clang/lib/Lex/PPDirectives.cpp:2205:7
    ...
```
bd1976bris pushed a commit that referenced this pull request Apr 9, 2026
Running gcc test c-c++-common/tsan/tls_race.c on s390 we get:

ThreadSanitizer: CHECK failed: tsan_platform_linux.cpp:618 "((thr_beg))
>= ((tls_addr))" (0x3ffaa35e140, 0x3ffaa35e250) (tid=2419930)
#0 __tsan::CheckUnwind() /devel/src/libsanitizer/tsan/tsan_rtl.cpp:696
(libtsan.so.2+0x91b57)
#1 __sanitizer::CheckFailed(char const*, int, char const*, unsigned long
long, unsigned long long)
/devel/src/libsanitizer/sanitizer_common/sanitizer_termination.cpp:86
(libtsan.so.2+0xd211b)
#2 __tsan::ImitateTlsWrite(__tsan::ThreadState*, unsigned long, unsigned
long) /devel/src/libsanitizer/tsan/tsan_platform_linux.cpp:618
(libtsan.so.2+0x8faa3)
#3 __tsan::ThreadStart(__tsan::ThreadState*, unsigned int, unsigned long
long, __sanitizer::ThreadType)
/devel/src/libsanitizer/tsan/tsan_rtl_thread.cpp:225
(libtsan.so.2+0xaadb5)
#4 __tsan_thread_start_func
/devel/src/libsanitizer/tsan/tsan_interceptors_posix.cpp:1065
(libtsan.so.2+0x3d34d)
llvm#5 start_thread <null> (libc.so.6+0xae70d) (BuildId:
d3b08de1b543c2d15d419bf861b3c2e4c01ac75b)
llvm#6 thread_start <null> (libc.so.6+0x12d2ff) (BuildId:
d3b08de1b543c2d15d419bf861b3c2e4c01ac75b)

In order to determine the static TLS blocks in GetStaticTlsBoundary we
iterate over the modules and try to find the largest range without a
gap. Here we might have that modules are spaced exactly by the
alignment. For example, for the failing test we have:

(gdb) p/x ranges.data_[0]
$1 = {begin = 0x3fff7f9e6b8, end = 0x3fff7f9e740, align = 0x8, tls_modid
= 0x3} (gdb) p/x ranges.data_[1]
$2 = {begin = 0x3fff7f9e740, end = 0x3fff7f9eed0, align = 0x40,
tls_modid = 0x2} (gdb) p/x ranges.data_[2]
$3 = {begin = 0x3fff7f9eed8, end = 0x3fff7f9eef8, align = 0x8, tls_modid
= 0x4} (gdb) p/x ranges.data_[3]
$4 = {begin = 0x3fff7f9eefc, end = 0x3fff7f9ef00, align = 0x4, tls_modid
= 0x1}

where ranges[3].begin == ranges[2].end + ranges[3].align holds. Since in
the loop a strict inequality test is used we compute the wrong address

(gdb) p/x *addr
$5 = 0x3fff7f9eefc

whereas 0x3fff7f9e6b8 is expected which is why we bail out in the
subsequent.
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