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i8 vectors do not have their sizes changed as I noticed regressions in some
tests when that was done.

Created using spr 1.3.5
dc03-work pushed a commit that referenced this pull request Feb 23, 2024
…lvm#80904)"

This reverts commit b1ac052.

This commit breaks coroutine splitting for non-swift calling convention
functions. In this example:

```ll
; ModuleID = 'repro.ll'
source_filename = "stdlib/test/runtime/test_llcl.mojo"
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

@0 = internal constant { i32, i32 } { i32 trunc (i64 sub (i64 ptrtoint (ptr @craSH to i64), i64 ptrtoint (ptr getelementptr inbounds ({ i32, i32 }, ptr @0, i32 0, i32 1) to i64)) to i32), i32 64 }

define dso_local void @af_suspend_fn(ptr %0, i64 %1, ptr %2) #0 {
  ret void
}

define dso_local void @craSH(ptr %0) #0 {
  %2 = call token @llvm.coro.id.async(i32 64, i32 8, i32 0, ptr @0)
  %3 = call ptr @llvm.coro.begin(token %2, ptr null)
  %4 = getelementptr inbounds { ptr, { ptr, ptr }, i64, { ptr, i1 }, i64, i64 }, ptr poison, i32 0, i32 0
  %5 = call ptr @llvm.coro.async.resume()
  store ptr %5, ptr %4, align 8
  %6 = call { ptr, ptr, ptr } (i32, ptr, ptr, ...) @llvm.coro.suspend.async.sl_p0p0p0s(i32 0, ptr %5, ptr @ctxt_proj_fn, ptr @af_suspend_fn, ptr poison, i64 -1, ptr poison)
  ret void
}

define dso_local ptr @ctxt_proj_fn(ptr %0) #0 {
  ret ptr %0
}

; Function Attrs: nomerge nounwind
declare { ptr, ptr, ptr } @llvm.coro.suspend.async.sl_p0p0p0s(i32, ptr, ptr, ...) #1

; Function Attrs: nounwind
declare token @llvm.coro.id.async(i32, i32, i32, ptr) #2

; Function Attrs: nounwind
declare ptr @llvm.coro.begin(token, ptr writeonly) #2

; Function Attrs: nomerge nounwind
declare ptr @llvm.coro.async.resume() #1

attributes #0 = { "target-features"="+adx,+aes,+avx,+avx2,+bmi,+bmi2,+clflushopt,+clwb,+clzero,+crc32,+cx16,+cx8,+f16c,+fma,+fsgsbase,+fxsr,+invpcid,+lzcnt,+mmx,+movbe,+mwaitx,+pclmul,+pku,+popcnt,+prfchw,+rdpid,+rdpru,+rdrnd,+rdseed,+sahf,+sha,+sse,+sse2,+sse3,+sse4.1,+sse4.2,+sse4a,+ssse3,+vaes,+vpclmulqdq,+wbnoinvd,+x87,+xsave,+xsavec,+xsaveopt,+xsaves" }
attributes #1 = { nomerge nounwind }
attributes #2 = { nounwind }
```

This verifier crashes after the `coro-split` pass with

```
cannot guarantee tail call due to mismatched parameter counts
  musttail call void @af_suspend_fn(ptr poison, i64 -1, ptr poison)
LLVM ERROR: Broken function
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.      Program arguments: opt ../../../reduced.ll -O0
 #0 0x00007f1d89645c0e __interceptor_backtrace.part.0 /build/gcc-11-XeT9lY/gcc-11-11.4.0/build/x86_64-linux-gnu/libsanitizer/asan/../../../../src/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:4193:28
 #1 0x0000556d94d254f7 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /home/ubuntu/modular/third-party/llvm-project/llvm/lib/Support/Unix/Signals.inc:723:22
 #2 0x0000556d94d19a2f llvm::sys::RunSignalHandlers() /home/ubuntu/modular/third-party/llvm-project/llvm/lib/Support/Signals.cpp:105:20
 llvm#3 0x0000556d94d1aa42 SignalHandler(int) /home/ubuntu/modular/third-party/llvm-project/llvm/lib/Support/Unix/Signals.inc:371:36
 llvm#4 0x00007f1d88e42520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 llvm#5 0x00007f1d88e969fc __pthread_kill_implementation ./nptl/pthread_kill.c:44:76
 llvm#6 0x00007f1d88e969fc __pthread_kill_internal ./nptl/pthread_kill.c:78:10
 llvm#7 0x00007f1d88e969fc pthread_kill ./nptl/pthread_kill.c:89:10
 llvm#8 0x00007f1d88e42476 gsignal ./signal/../sysdeps/posix/raise.c:27:6
 llvm#9 0x00007f1d88e287f3 abort ./stdlib/abort.c:81:7
 llvm#10 0x0000556d8944be01 std::vector<llvm::json::Value, std::allocator<llvm::json::Value>>::size() const /usr/include/c++/11/bits/stl_vector.h:919:40
 llvm#11 0x0000556d8944be01 bool std::operator==<llvm::json::Value, std::allocator<llvm::json::Value>>(std::vector<llvm::json::Value, std::allocator<llvm::json::Value>> const&, std::vector<llvm::json::Value, std::allocator<llvm::json::Value>> const&) /usr/include/c++/11/bits/stl_vector.h:1893:23
 llvm#12 0x0000556d8944be01 llvm::json::operator==(llvm::json::Array const&, llvm::json::Array const&) /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/Support/JSON.h:572:69
 llvm#13 0x0000556d8944be01 llvm::json::operator==(llvm::json::Value const&, llvm::json::Value const&) (.cold) /home/ubuntu/modular/third-party/llvm-project/llvm/lib/Support/JSON.cpp:204:28
 llvm#14 0x0000556d949ed2bd llvm::report_fatal_error(char const*, bool) /home/ubuntu/modular/third-party/llvm-project/llvm/lib/Support/ErrorHandling.cpp:82:70
 llvm#15 0x0000556d8e37e876 llvm::SmallVectorBase<unsigned int>::size() const /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/ADT/SmallVector.h:91:32
 llvm#16 0x0000556d8e37e876 llvm::SmallVectorTemplateCommon<llvm::DiagnosticInfoOptimizationBase::Argument, void>::end() /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/ADT/SmallVector.h:282:41
 llvm#17 0x0000556d8e37e876 llvm::SmallVector<llvm::DiagnosticInfoOptimizationBase::Argument, 4u>::~SmallVector() /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/ADT/SmallVector.h:1215:24
 llvm#18 0x0000556d8e37e876 llvm::DiagnosticInfoOptimizationBase::~DiagnosticInfoOptimizationBase() /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/IR/DiagnosticInfo.h:413:7
 llvm#19 0x0000556d8e37e876 llvm::DiagnosticInfoIROptimization::~DiagnosticInfoIROptimization() /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/IR/DiagnosticInfo.h:622:7
 llvm#20 0x0000556d8e37e876 llvm::OptimizationRemark::~OptimizationRemark() /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/IR/DiagnosticInfo.h:689:7
 llvm#21 0x0000556d8e37e876 operator() /home/ubuntu/modular/third-party/llvm-project/llvm/lib/Transforms/Coroutines/CoroSplit.cpp:2213:14
 llvm#22 0x0000556d8e37e876 emit<llvm::CoroSplitPass::run(llvm::LazyCallGraph::SCC&, llvm::CGSCCAnalysisManager&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&)::<lambda()> > /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/Analysis/OptimizationRemarkEmitter.h:83:12
 llvm#23 0x0000556d8e37e876 llvm::CoroSplitPass::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) /home/ubuntu/modular/third-party/llvm-project/llvm/lib/Transforms/Coroutines/CoroSplit.cpp:2212:13
 llvm#24 0x0000556d8c36ecb1 llvm::detail::PassModel<llvm::LazyCallGraph::SCC, llvm::CoroSplitPass, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/IR/PassManagerInternal.h:91:3
 llvm#25 0x0000556d91c1a84f llvm::PassManager<llvm::LazyCallGraph::SCC, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) /home/ubuntu/modular/third-party/llvm-project/llvm/lib/Analysis/CGSCCPassManager.cpp:90:12
 llvm#26 0x0000556d8c3690d1 llvm::detail::PassModel<llvm::LazyCallGraph::SCC, llvm::PassManager<llvm::LazyCallGraph::SCC, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/IR/PassManagerInternal.h:91:3
 llvm#27 0x0000556d91c2162d llvm::ModuleToPostOrderCGSCCPassAdaptor::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /home/ubuntu/modular/third-party/llvm-project/llvm/lib/Analysis/CGSCCPassManager.cpp:278:18
 llvm#28 0x0000556d8c369035 llvm::detail::PassModel<llvm::Module, llvm::ModuleToPostOrderCGSCCPassAdaptor, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/IR/PassManagerInternal.h:91:3
 llvm#29 0x0000556d9457abc5 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/IR/PassManager.h:247:20
 llvm#30 0x0000556d8e30979e llvm::CoroConditionalWrapper::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /home/ubuntu/modular/third-party/llvm-project/llvm/lib/Transforms/Coroutines/CoroConditionalWrapper.cpp:19:74
 llvm#31 0x0000556d8c365755 llvm::detail::PassModel<llvm::Module, llvm::CoroConditionalWrapper, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/IR/PassManagerInternal.h:91:3
 llvm#32 0x0000556d9457abc5 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/IR/PassManager.h:247:20
 llvm#33 0x0000556d89818556 llvm::SmallPtrSetImplBase::isSmall() const /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/ADT/SmallPtrSet.h:196:33
 llvm#34 0x0000556d89818556 llvm::SmallPtrSetImplBase::~SmallPtrSetImplBase() /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/ADT/SmallPtrSet.h:84:17
 llvm#35 0x0000556d89818556 llvm::SmallPtrSetImpl<llvm::AnalysisKey*>::~SmallPtrSetImpl() /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/ADT/SmallPtrSet.h:321:7
 llvm#36 0x0000556d89818556 llvm::SmallPtrSet<llvm::AnalysisKey*, 2u>::~SmallPtrSet() /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/ADT/SmallPtrSet.h:427:7
 llvm#37 0x0000556d89818556 llvm::PreservedAnalyses::~PreservedAnalyses() /home/ubuntu/modular/third-party/llvm-project/llvm/include/llvm/IR/Analysis.h:109:7
 llvm#38 0x0000556d89818556 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::function<void (llvm::PassBuilder&)>>, llvm::opt_tool::OutputKind, llvm::opt_tool::VerifierKind, bool, bool, bool, bool, bool, bool, bool) /home/ubuntu/modular/third-party/llvm-project/llvm/tools/opt/NewPMDriver.cpp:532:10
 llvm#39 0x0000556d897e3939 optMain /home/ubuntu/modular/third-party/llvm-project/llvm/tools/opt/optdriver.cpp:737:27
 llvm#40 0x0000556d89455461 main /home/ubuntu/modular/third-party/llvm-project/llvm/tools/opt/opt.cpp:25:33
 llvm#41 0x00007f1d88e29d90 __libc_start_call_main ./csu/../sysdeps/nptl/libc_start_call_main.h:58:16
 llvm#42 0x00007f1d88e29e40 call_init ./csu/../csu/libc-start.c:128:20
 llvm#43 0x00007f1d88e29e40 __libc_start_main ./csu/../csu/libc-start.c:379:5
 llvm#44 0x0000556d897b6335 _start (/home/ubuntu/modular/.derived/third-party/llvm-project/build-relwithdebinfo-asan/bin/opt+0x150c335)
Aborted (core dumped)
dc03-work pushed a commit that referenced this pull request Mar 8, 2024
…ter partial ordering when determining primary template (llvm#82417)

Consider the following:
```
struct A {
  static constexpr bool x = true;
};

template<typename T, typename U>
void f(T, U) noexcept(T::y); // #1, error: no member named 'y' in 'A'

template<typename T, typename U>
void f(T, U*) noexcept(T::x); // #2

template<>
void f(A, int*) noexcept; // explicit specialization of #2
```

We currently instantiate the exception specification of all candidate
function template specializations when deducting template arguments for
an explicit specialization, which results in a error despite `#1` not
being selected by partial ordering as the most specialized template.
According to [except.spec] p13:
> An exception specification is considered to be needed when: 
> - [...]
> - the exception specification is compared to that of another
declaration (e.g., an explicit specialization or an overriding virtual
function);

Assuming that "comparing declarations" means "determining whether the
declarations correspond and declare the same entity" (per [basic.scope.scope] p4 and
[basic.link] p11.1, respectively), the exception specification does _not_ need to be
instantiated until _after_ partial ordering, at which point we determine
whether the implicitly instantiated specialization and the explicit
specialization declare the same entity (the determination of whether two
functions/function templates correspond does not consider the exception
specifications).

This patch defers the instantiation of the exception specification until
a single function template specialization is selected via partial
ordering, matching the behavior of GCC, EDG, and
MSVC: see https://godbolt.org/z/Ebb6GTcWE.
dc03-work pushed a commit that referenced this pull request Mar 11, 2024
TestCases/Misc/Linux/sigaction.cpp fails because dlsym() may call malloc
on failure. And then the wrapped malloc appears to access thread local
storage using global dynamic accesses, thus calling
___interceptor___tls_get_addr, before REAL(__tls_get_addr) has
been set, so we get a crash inside ___interceptor___tls_get_addr. For
example, this can happen when looking up __isoc23_scanf which might not
exist in some libcs.

Fix this by marking the thread local variable accessed inside the
debug checks as "initial-exec", which does not require __tls_get_addr.

This is probably a better alternative to llvm#83886.

This fixes a different crash but is related to llvm#46204.

Backtrace:
```
#0 0x0000000000000000 in ?? ()
#1 0x00007ffff6a9d89e in ___interceptor___tls_get_addr (arg=0x7ffff6b27be8) at /path/to/llvm/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp:2759
#2 0x00007ffff6a46bc6 in __sanitizer::CheckedMutex::LockImpl (this=0x7ffff6b27be8, pc=140737331846066) at /path/to/llvm/compiler-rt/lib/sanitizer_common/sanitizer_mutex.cpp:218
llvm#3 0x00007ffff6a448b2 in __sanitizer::CheckedMutex::Lock (this=0x7ffff6b27be8, this@entry=0x730000000580) at /path/to/llvm/compiler-rt/lib/tsan/rtl/../../sanitizer_common/sanitizer_mutex.h:129
llvm#4 __sanitizer::Mutex::Lock (this=0x7ffff6b27be8, this@entry=0x730000000580) at /path/to/llvm/compiler-rt/lib/tsan/rtl/../../sanitizer_common/sanitizer_mutex.h:167
llvm#5 0x00007ffff6abdbb2 in __sanitizer::GenericScopedLock<__sanitizer::Mutex>::GenericScopedLock (mu=0x730000000580, this=<optimized out>) at /path/to/llvm/compiler-rt/lib/tsan/rtl/../../sanitizer_common/sanitizer_mutex.h:383
llvm#6 __sanitizer::SizeClassAllocator64<__tsan::AP64>::GetFromAllocator (this=0x7ffff7487dc0 <__tsan::allocator_placeholder>, stat=stat@entry=0x7ffff570db68, class_id=11, chunks=chunks@entry=0x7ffff5702cc8, n_chunks=n_chunks@entry=128) at /path/to/llvm/compiler-rt/lib/tsan/rtl/../../sanitizer_common/sanitizer_allocator_primary64.h:207
llvm#7 0x00007ffff6abdaa0 in __sanitizer::SizeClassAllocator64LocalCache<__sanitizer::SizeClassAllocator64<__tsan::AP64> >::Refill (this=<optimized out>, c=c@entry=0x7ffff5702cb8, allocator=<optimized out>, class_id=<optimized out>)
 at /path/to/llvm/compiler-rt/lib/tsan/rtl/../../sanitizer_common/sanitizer_allocator_local_cache.h:103
llvm#8 0x00007ffff6abd731 in __sanitizer::SizeClassAllocator64LocalCache<__sanitizer::SizeClassAllocator64<__tsan::AP64> >::Allocate (this=0x7ffff6b27be8, allocator=0x7ffff5702cc8, class_id=140737311157448)
 at /path/to/llvm/compiler-rt/lib/tsan/rtl/../../sanitizer_common/sanitizer_allocator_local_cache.h:39
llvm#9 0x00007ffff6abc397 in __sanitizer::CombinedAllocator<__sanitizer::SizeClassAllocator64<__tsan::AP64>, __sanitizer::LargeMmapAllocatorPtrArrayDynamic>::Allocate (this=0x7ffff5702cc8, cache=0x7ffff6b27be8, size=<optimized out>, size@entry=175, alignment=alignment@entry=16)
 at /path/to/llvm/compiler-rt/lib/tsan/rtl/../../sanitizer_common/sanitizer_allocator_combined.h:69
llvm#10 0x00007ffff6abaa6a in __tsan::user_alloc_internal (thr=0x7ffff7ebd980, pc=140737331499943, sz=sz@entry=175, align=align@entry=16, signal=true) at /path/to/llvm/compiler-rt/lib/tsan/rtl/tsan_mman.cpp:198
llvm#11 0x00007ffff6abb0d1 in __tsan::user_alloc (thr=0x7ffff6b27be8, pc=140737331846066, sz=11, sz@entry=175) at /path/to/llvm/compiler-rt/lib/tsan/rtl/tsan_mman.cpp:223
llvm#12 0x00007ffff6a693b5 in ___interceptor_malloc (size=175) at /path/to/llvm/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp:666
llvm#13 0x00007ffff7fce7f2 in malloc (size=175) at ../include/rtld-malloc.h:56
llvm#14 __GI__dl_exception_create_format (exception=exception@entry=0x7fffffffd0d0, objname=0x7ffff7fc3550 "/path/to/llvm/compiler-rt/cmake-build-all-sanitizers/lib/linux/libclang_rt.tsan-x86_64.so",
 fmt=fmt@entry=0x7ffff7ff2db9 "undefined symbol: %s%s%s") at ./elf/dl-exception.c:157
llvm#15 0x00007ffff7fd50e8 in _dl_lookup_symbol_x (undef_name=0x7ffff6af868b "__isoc23_scanf", undef_map=<optimized out>, ref=0x7fffffffd148, symbol_scope=<optimized out>, version=<optimized out>, type_class=0, flags=2, skip_map=0x7ffff7fc35e0) at ./elf/dl-lookup.c:793
--Type <RET> for more, q to quit, c to continue without paging--
llvm#16 0x00007ffff656d6ed in do_sym (handle=<optimized out>, name=0x7ffff6af868b "__isoc23_scanf", who=0x7ffff6a3bb84 <__interception::InterceptFunction(char const*, unsigned long*, unsigned long, unsigned long)+36>, vers=vers@entry=0x0, flags=flags@entry=2) at ./elf/dl-sym.c:146
llvm#17 0x00007ffff656d9dd in _dl_sym (handle=<optimized out>, name=<optimized out>, who=<optimized out>) at ./elf/dl-sym.c:195
llvm#18 0x00007ffff64a2854 in dlsym_doit (a=a@entry=0x7fffffffd3b0) at ./dlfcn/dlsym.c:40
llvm#19 0x00007ffff7fcc489 in __GI__dl_catch_exception (exception=exception@entry=0x7fffffffd310, operate=0x7ffff64a2840 <dlsym_doit>, args=0x7fffffffd3b0) at ./elf/dl-catch.c:237
llvm#20 0x00007ffff7fcc5af in _dl_catch_error (objname=0x7fffffffd368, errstring=0x7fffffffd370, mallocedp=0x7fffffffd367, operate=<optimized out>, args=<optimized out>) at ./elf/dl-catch.c:256
llvm#21 0x00007ffff64a2257 in _dlerror_run (operate=operate@entry=0x7ffff64a2840 <dlsym_doit>, args=args@entry=0x7fffffffd3b0) at ./dlfcn/dlerror.c:138
llvm#22 0x00007ffff64a28e5 in dlsym_implementation (dl_caller=<optimized out>, name=<optimized out>, handle=<optimized out>) at ./dlfcn/dlsym.c:54
llvm#23 ___dlsym (handle=<optimized out>, name=<optimized out>) at ./dlfcn/dlsym.c:68
llvm#24 0x00007ffff6a3bb84 in __interception::GetFuncAddr (name=0x7ffff6af868b "__isoc23_scanf", trampoline=140737311157448) at /path/to/llvm/compiler-rt/lib/interception/interception_linux.cpp:42
llvm#25 __interception::InterceptFunction (name=0x7ffff6af868b "__isoc23_scanf", ptr_to_real=0x7ffff74850e8 <__interception::real___isoc23_scanf>, func=11, trampoline=140737311157448)
 at /path/to/llvm/compiler-rt/lib/interception/interception_linux.cpp:61
llvm#26 0x00007ffff6a9f2d9 in InitializeCommonInterceptors () at /path/to/llvm/compiler-rt/lib/tsan/rtl/../../sanitizer_common/sanitizer_common_interceptors.inc:10315
```

Reviewed By: vitalybuka, MaskRay

Pull Request: llvm#83890
dc03-work pushed a commit that referenced this pull request May 14, 2024
…e exception specification of a function (llvm#90760)

[temp.deduct.general] p6 states:
> At certain points in the template argument deduction process it is
necessary to take a function type that makes use of template parameters
and replace those template parameters with the corresponding template
arguments.
This is done at the beginning of template argument deduction when any
explicitly specified template arguments are substituted into the
function type, and again at the end of template argument deduction when
any template arguments that were deduced or obtained from default
arguments are substituted.

[temp.deduct.general] p7 goes on to say:
> The _deduction substitution loci_ are
> - the function type outside of the _noexcept-specifier_,
> - the explicit-specifier,
> - the template parameter declarations, and
> - the template argument list of a partial specialization
>
> The substitution occurs in all types and expressions that are used in
the deduction substitution loci. [...]

Consider the following:
```cpp
struct A
{
    static constexpr bool x = true;
};

template<typename T, typename U>
void f(T, U) noexcept(T::x); // #1

template<typename T, typename U>
void f(T, U*) noexcept(T::y); // #2

template<>
void f<A>(A, int*) noexcept; // clang currently accepts, GCC and EDG reject
```

Currently, `Sema::SubstituteExplicitTemplateArguments` will substitute
into the _noexcept-specifier_ when deducing template arguments from a
function declaration or when deducing template arguments for taking the
address of a function template (and the substitution is treated as a
SFINAE context). In the above example, `#1` is selected as the primary
template because substitution of the explicit template arguments into
the _noexcept-specifier_ of `#2` failed, which resulted in the candidate
being ignored.

This behavior is incorrect ([temp.deduct.general] note 4 says as much), and
this patch corrects it by deferring all substitution into the
_noexcept-specifier_ until it is instantiated.

As part of the necessary changes to make this patch work, the
instantiation of the exception specification of a function template
specialization when taking the address of a function template is changed
to only occur for the function selected by overload resolution per
[except.spec] p13.1 (as opposed to being instantiated for every candidate).
dc03-work pushed a commit that referenced this pull request May 14, 2024
…ined member functions & member function templates (llvm#88963)

Consider the following snippet from the discussion of CWG2847 on the core reflector:
```
template<typename T>
concept C = sizeof(T) <= sizeof(long);

template<typename T>
struct A 
{
    template<typename U>
    void f(U) requires C<U>; // #1, declares a function template 

    void g() requires C<T>; // #2, declares a function

    template<>
    void f(char);  // llvm#3, an explicit specialization of a function template that declares a function
};

template<>
template<typename U>
void A<short>::f(U) requires C<U>; // llvm#4, an explicit specialization of a function template that declares a function template

template<>
template<>
void A<int>::f(int); // llvm#5, an explicit specialization of a function template that declares a function

template<>
void A<long>::g(); // llvm#6, an explicit specialization of a function that declares a function
```

A number of problems exist:
- Clang rejects `llvm#4` because the trailing _requires-clause_ has `U`
substituted with the wrong template parameter depth when
`Sema::AreConstraintExpressionsEqual` is called to determine whether it
matches the trailing _requires-clause_ of the implicitly instantiated
function template.
- Clang rejects `llvm#5` because the function template specialization
instantiated from `A<int>::f` has a trailing _requires-clause_, but `llvm#5`
does not (nor can it have one as it isn't a templated function).
- Clang rejects `llvm#6` for the same reasons it rejects `llvm#5`.

This patch resolves these issues by making the following changes:
- To fix `llvm#4`, `Sema::AreConstraintExpressionsEqual` is passed
`FunctionTemplateDecl`s when comparing the trailing _requires-clauses_
of `llvm#4` and the function template instantiated from `#1`.
- To fix `llvm#5` and `llvm#6`, the trailing _requires-clauses_ are not compared
for explicit specializations that declare functions.

In addition to these changes, `CheckMemberSpecialization` now considers
constraint satisfaction/constraint partial ordering when determining
which member function is specialized by an explicit specialization of a
member function for an implicit instantiation of a class template (we
previously would select the first function that has the same type as the
explicit specialization). With constraints taken under consideration, we
match EDG's behavior for these declarations.
dc03-work pushed a commit that referenced this pull request May 20, 2024
...which caused issues like

> ==42==ERROR: AddressSanitizer failed to deallocate 0x32 (50) bytes at
address 0x117e0000 (error code: 28)
> ==42==Cannot dump memory map on emscriptenAddressSanitizer: CHECK
failed: sanitizer_common.cpp:81 "((0 && "unable to unmmap")) != (0)"
(0x0, 0x0) (tid=288045824)
> #0 0x14f73b0c in __asan::CheckUnwind()+0x14f73b0c
(this.program+0x14f73b0c)
> #1 0x14f8a3c2 in __sanitizer::CheckFailed(char const*, int, char
const*, unsigned long long, unsigned long long)+0x14f8a3c2
(this.program+0x14f8a3c2)
> #2 0x14f7d6e1 in __sanitizer::ReportMunmapFailureAndDie(void*,
unsigned long, int, bool)+0x14f7d6e1 (this.program+0x14f7d6e1)
> llvm#3 0x14f81fbd in __sanitizer::UnmapOrDie(void*, unsigned
long)+0x14f81fbd (this.program+0x14f81fbd)
> llvm#4 0x14f875df in __sanitizer::SuppressionContext::ParseFromFile(char
const*)+0x14f875df (this.program+0x14f875df)
> llvm#5 0x14f74eab in __asan::InitializeSuppressions()+0x14f74eab
(this.program+0x14f74eab)
> llvm#6 0x14f73a1a in __asan::AsanInitInternal()+0x14f73a1a
(this.program+0x14f73a1a)

when trying to use an ASan suppressions file under Emscripten: Even
though it would be considered OK by SUSv4, the Emscripten runtime states
"We don't support partial munmapping" (see

<emscripten-core/emscripten@f4115eb>
"Implement MAP_ANONYMOUS on top of malloc in STANDALONE_WASM mode
(llvm#16289)").

Co-authored-by: Stephan Bergmann <stephan.bergmann@allotropia.de>
dc03-work pushed a commit that referenced this pull request May 20, 2024
…ication as used during partial ordering (llvm#91534)

We do not deduce template arguments from the exception specification
when determining the primary template of a function template
specialization or when taking the address of a function template.
Therefore, this patch changes `isAtLeastAsSpecializedAs` such that we do
not mark template parameters in the exception specification as 'used'
during partial ordering (per [temp.deduct.partial]
p12) to prevent the following from being ambiguous:

```
template<typename T, typename U>
void f(U) noexcept(noexcept(T())); // #1

template<typename T>
void f(T*) noexcept; // #2

template<>
void f<int>(int*) noexcept; // currently ambiguous, selects #2 with this patch applied 
```

Although there is no corresponding wording in the standard (see core issue filed here
cplusplus/CWG#537), this seems
to be the intended behavior given the definition of _deduction
substitution loci_ in [temp.deduct.general] p7 (and EDG does the same thing).
dc03-work pushed a commit that referenced this pull request May 20, 2024
…erSize (llvm#67657)"

This reverts commit f0b3654.

This commit triggers UB by reading an uninitialized variable.

`UP.PartialThreshold` is used uninitialized in `getUnrollingPreferences()` when
it is called from `LoopVectorizationPlanner::executePlan()`. In this case the
`UP` variable is created on the stack and its fields are not initialized.

```
==8802==WARNING: MemorySanitizer: use-of-uninitialized-value
    #0 0x557c0b081b99 in llvm::BasicTTIImplBase<llvm::X86TTIImpl>::getUnrollingPreferences(llvm::Loop*, llvm::ScalarEvolution&, llvm::TargetTransformInfo::UnrollingPreferences&, llvm::OptimizationRemarkEmitter*) llvm-project/llvm/include/llvm/CodeGen/BasicTTIImpl.h
    #1 0x557c0b07a40c in llvm::TargetTransformInfo::Model<llvm::X86TTIImpl>::getUnrollingPreferences(llvm::Loop*, llvm::ScalarEvolution&, llvm::TargetTransformInfo::UnrollingPreferences&, llvm::OptimizationRemarkEmitter*) llvm-project/llvm/include/llvm/Analysis/TargetTransformInfo.h:2277:17
    #2 0x557c0f5d69ee in llvm::TargetTransformInfo::getUnrollingPreferences(llvm::Loop*, llvm::ScalarEvolution&, llvm::TargetTransformInfo::UnrollingPreferences&, llvm::OptimizationRemarkEmitter*) const llvm-project/llvm/lib/Analysis/TargetTransformInfo.cpp:387:19
    llvm#3 0x557c0e6b96a0 in llvm::LoopVectorizationPlanner::executePlan(llvm::ElementCount, unsigned int, llvm::VPlan&, llvm::InnerLoopVectorizer&, llvm::DominatorTree*, bool, llvm::DenseMap<llvm::SCEV const*, llvm::Value*, llvm::DenseMapInfo<llvm::SCEV const*, void>, llvm::detail::DenseMapPair<llvm::SCEV const*, llvm::Value*>> const*) llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:7624:7
    llvm#4 0x557c0e6e4b63 in llvm::LoopVectorizePass::processLoop(llvm::Loop*) llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:10253:13
    llvm#5 0x557c0e6f2429 in llvm::LoopVectorizePass::runImpl(llvm::Function&, llvm::ScalarEvolution&, llvm::LoopInfo&, llvm::TargetTransformInfo&, llvm::DominatorTree&, llvm::BlockFrequencyInfo*, llvm::TargetLibraryInfo*, llvm::DemandedBits&, llvm::AssumptionCache&, llvm::LoopAccessInfoManager&, llvm::OptimizationRemarkEmitter&, llvm::ProfileSummaryInfo*) llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:10344:30
    llvm#6 0x557c0e6f2f97 in llvm::LoopVectorizePass::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:10383:9

[...]

  Uninitialized value was created by an allocation of 'UP' in the stack frame
    #0 0x557c0e6b961e in llvm::LoopVectorizationPlanner::executePlan(llvm::ElementCount, unsigned int, llvm::VPlan&, llvm::InnerLoopVectorizer&, llvm::DominatorTree*, bool, llvm::DenseMap<llvm::SCEV const*, llvm::Value*, llvm::DenseMapInfo<llvm::SCEV const*, void>, llvm::detail::DenseMapPair<llvm::SCEV const*, llvm::Value*>> const*) llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:7623:3
```
dc03-work pushed a commit that referenced this pull request May 20, 2024
…vm#90820)

This solves some ambuguity introduced in P0522 regarding how
template template parameters are partially ordered, and should reduce
the negative impact of enabling `-frelaxed-template-template-args`
by default.

When performing template argument deduction, a template template
parameter
containing no packs should be more specialized than one that does.

Given the following example:
```C++
template<class T2> struct A;
template<template<class ...T3s> class TT1, class T4> struct A<TT1<T4>>; // #1
template<template<class    T5 > class TT2, class T6> struct A<TT2<T6>>; // #2

template<class T1> struct B;
template struct A<B<char>>;
```

Prior to P0522, candidate `#2` would be more specialized.
After P0522, neither is more specialized, so this becomes ambiguous.
With this change, `#2` becomes more specialized again,
maintaining compatibility with pre-P0522 implementations.

The problem is that in P0522, candidates are at least as specialized
when matching packs to fixed-size lists both ways, whereas before,
a fixed-size list is more specialized.

This patch keeps the original behavior when checking template arguments
outside deduction, but restores this aspect of pre-P0522 matching
during deduction.

---

Since this changes provisional implementation of CWG2398 which has
not been released yet, and already contains a changelog entry,
we don't provide a changelog entry here.
dc03-work pushed a commit that referenced this pull request May 23, 2024
'reduction' has a few restrictions over normal 'var-list' clauses:

1- On parallel, a num_gangs can only have 1 argument when combined with
reduction. These two aren't able to be combined on any other of the
compute constructs however.

2- The vars all must be 'numerical data types' types of some sort, or a
'composite of numerical data types'. A list of types is given in the
standard as a minimum, so we choose 'isScalar', which covers all of
these types and keeps types that are actually numeric. Other compilers
don't seem to implement the 'composite of numerical data types', though
we do.

3- Because of the above restrictions, member-of-composite is not
allowed, so any access via a memberexpr is disallowed. Array-element and
sub-arrays (aka array sections) are both permitted, so long as they meet
the requirements of #2.

This patch implements all of these for compute constructs.
dc03-work pushed a commit that referenced this pull request May 23, 2024
…llvm#92855)

This solves some ambuguity introduced in P0522 regarding how template
template parameters are partially ordered, and should reduce the
negative impact of enabling `-frelaxed-template-template-args` by
default.

When performing template argument deduction, we extend the provisional
wording introduced in llvm#89807 so
it also covers deduction of class templates.

Given the following example:
```C++
template <class T1, class T2 = float> struct A;
template <class T3> struct B;

template <template <class T4> class TT1, class T5> struct B<TT1<T5>>;   // #1
template <class T6, class T7>                      struct B<A<T6, T7>>; // #2

template struct B<A<int>>;
```
Prior to P0522, `#2` was picked. Afterwards, this became ambiguous. This
patch restores the pre-P0522 behavior, `#2` is picked again.

This has the beneficial side effect of making the following code valid:
```C++
template<class T, class U> struct A {};
A<int, float> v;
template<template<class> class TT> void f(TT<int>);

// OK: TT picks 'float' as the default argument for the second parameter.
void g() { f(v); }
```

---

Since this changes provisional implementation of CWG2398 which has not
been released yet, and already contains a changelog entry, we don't
provide a changelog entry here.
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