Closed
Description
Since Clang 16, attached (reduced) code fails and causes an ICE in the front-end of LLVM-based compilers on Arm platforms.
This was tested with Clang 16, 17 (latest from apt.llvm.com) and ArmClang 23.04 (based on 16). This was working with Clang<=15 and ArmClang<=22.1
crash.c:
#include <arm_sve.h>
#include <omp.h>
void crash() {
#pragma omp parallel
{
// svfloat64_t db_vec0 = svld1(pg, b + i + fn);
svbool_t pg = svwhilelt_b64(0, 1);
}
}failing command:
clang-17 crash.c -fopenmp -o crash
crash still happens with:
clang-17 -emit-llvm -Xclang -disable-llvm-passes crash.c -fopenmp -cuncommenting any of the two SVE lines will trigger the crash (so the SVE command used is not the problem), but removing the pragma or -fopenmp correctly works (with expected errors).
Output:
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: clang-17 -emit-llvm -Xclang -disable-llvm-passes crash.c -fopenmp -c
1. crash.c:7:17: current parser token '='
2. crash.c:3:14: parsing function body 'crash'
3. crash.c:3:14: in compound statement ('{}')
4. crash.c:5:3: in compound statement ('{}')
Stack dump without symbol names (ensure you have llvm-symbolizer in your PATH or set the environment var `LLVM_SYMBOLIZER_PATH` to point to it):
0 libLLVM-17.so.1 0x0000ffff9615cc24 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) + 80
1 libLLVM-17.so.1 0x0000ffff9615aeec llvm::sys::RunSignalHandlers() + 112
2 libLLVM-17.so.1 0x0000ffff960b920c
3 linux-vdso.so.1 0x0000ffff9fc635d0 __kernel_rt_sigreturn + 0
4 libclang-cpp.so.17 0x0000ffff9cdf0bd8 clang::ASTContext::getFunctionFeatureMap(llvm::StringMap<bool, llvm::MallocAllocator>&, clang::GlobalDecl) const + 84
5 libclang-cpp.so.17 0x0000ffff9d5f5c20 clang::Sema::CheckVariableDeclarationType(clang::VarDecl*) + 2312
6 libclang-cpp.so.17 0x0000ffff9d5f3b34 clang::Sema::CheckVariableDeclaration(clang::VarDecl*, clang::LookupResult&) + 36
7 libclang-cpp.so.17 0x0000ffff9d5f138c clang::Sema::ActOnVariableDeclarator(clang::Scope*, clang::Declarator&, clang::DeclContext*, clang::TypeSourceInfo*, clang::LookupResult&, llvm::MutableArrayRef<clang::TemplateParameterList*>, bool&, llvm::ArrayRef<clang::BindingDecl*>) + 7340
8 libclang-cpp.so.17 0x0000ffff9d5e9b10 clang::Sema::HandleDeclarator(clang::Scope*, clang::Declarator&, llvm::MutableArrayRef<clang::TemplateParameterList*>) + 2344
9 libclang-cpp.so.17 0x0000ffff9d5e9134 clang::Sema::ActOnDeclarator(clang::Scope*, clang::Declarator&) + 320
10 libclang-cpp.so.17 0x0000ffff9cd101a4 clang::Parser::ParseDeclarationAfterDeclaratorAndAttributes(clang::Declarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::ForRangeInit*) + 276
11 libclang-cpp.so.17 0x0000ffff9cd0e800 clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::SourceLocation*, clang::Parser::ForRangeInit*) + 916
12 libclang-cpp.so.17 0x0000ffff9cd0de64 clang::Parser::ParseSimpleDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::ParsedAttributes&, bool, clang::Parser::ForRangeInit*, clang::SourceLocation*) + 692
13 libclang-cpp.so.17 0x0000ffff9cd0dab8 clang::Parser::ParseDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::ParsedAttributes&, clang::SourceLocation*) + 1048
14 libclang-cpp.so.17 0x0000ffff9cd8b858 clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::ParsedAttributes&, clang::ParsedAttributes&) + 5716
15 libclang-cpp.so.17 0x0000ffff9cd8a008 clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*) + 288
16 libclang-cpp.so.17 0x0000ffff9cd916e0 clang::Parser::ParseCompoundStatementBody(bool) + 1608
17 libclang-cpp.so.17 0x0000ffff9cd8a964 clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::ParsedAttributes&, clang::ParsedAttributes&) + 1888
18 libclang-cpp.so.17 0x0000ffff9cd8a008 clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*) + 288
19 libclang-cpp.so.17 0x0000ffff9cd89e98 clang::Parser::ParseStatement(clang::SourceLocation*, clang::Parser::ParsedStmtContext) + 96
20 libclang-cpp.so.17 0x0000ffff9cd7106c clang::Parser::ParseOpenMPDeclarativeOrExecutableDirective(clang::Parser::ParsedStmtContext, bool) + 2880
21 libclang-cpp.so.17 0x0000ffff9cd8b54c clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::ParsedAttributes&, clang::ParsedAttributes&) + 4936
22 libclang-cpp.so.17 0x0000ffff9cd8a008 clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*) + 288
23 libclang-cpp.so.17 0x0000ffff9cd916e0 clang::Parser::ParseCompoundStatementBody(bool) + 1608
24 libclang-cpp.so.17 0x0000ffff9cd925f0 clang::Parser::ParseFunctionStatementBody(clang::Decl*, clang::Parser::ParseScope&) + 188
25 libclang-cpp.so.17 0x0000ffff9cda9b44 clang::Parser::ParseFunctionDefinition(clang::ParsingDeclarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::LateParsedAttrList*) + 3068
26 libclang-cpp.so.17 0x0000ffff9cd0f2cc clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::SourceLocation*, clang::Parser::ForRangeInit*) + 3680
27 libclang-cpp.so.17 0x0000ffff9cda8dac clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) + 936
28 libclang-cpp.so.17 0x0000ffff9cda87e8 clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) + 368
29 libclang-cpp.so.17 0x0000ffff9cda7d70 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) + 2164
30 libclang-cpp.so.17 0x0000ffff9cda6474 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) + 1228
31 libclang-cpp.so.17 0x0000ffff9ccfba1c clang::ParseAST(clang::Sema&, bool, bool) + 636
32 libclang-cpp.so.17 0x0000ffff9e7b46f4 clang::FrontendAction::Execute() + 112
33 libclang-cpp.so.17 0x0000ffff9e745f34 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) + 776
34 libclang-cpp.so.17 0x0000ffff9e8294cc clang::ExecuteCompilerInvocation(clang::CompilerInstance*) + 520
35 clang-17 0x0000aaaab759c240 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) + 1904
36 clang-17 0x0000aaaab75998c4
37 libclang-cpp.so.17 0x0000ffff9e470ec8
38 libLLVM-17.so.1 0x0000ffff960b8f80 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) + 160
39 libclang-cpp.so.17 0x0000ffff9e470500 clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const + 332
40 libclang-cpp.so.17 0x0000ffff9e441488 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const + 744
41 libclang-cpp.so.17 0x0000ffff9e441690 clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const + 136
42 libclang-cpp.so.17 0x0000ffff9e45868c clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) + 332
43 clang-17 0x0000aaaab7598fc4 clang_main(int, char**, llvm::ToolContext const&) + 9964
44 clang-17 0x0000aaaab75a48b0 main + 48
45 libc.so.6 0x0000ffff95066dc0
46 libc.so.6 0x0000ffff95066e98 __libc_start_main + 152
47 clang-17 0x0000aaaab7596570 _start + 48
clang-17: error: clang frontend command failed with exit code 139 (use -v to see invocation)
Ubuntu clang version 17.0.0 (++20230328090103+fa3cb517e4a5-1~exp1~20230328090118.37)
Target: aarch64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
clang-17: note: diagnostic msg:
********************
PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang-17: note: diagnostic msg: /tmp/crash-4c89d6.c
clang-17: note: diagnostic msg: /tmp/crash-4c89d6.sh
clang-17: note: diagnostic msg:
********************Reproducer is in crash.zip
Another failing project which shows the same issue is https://github.com/ARM-software/HPCG_for_Arm when compiling for neoverse-v1. Offending code is different but same symptoms, the first SVE command in a #pragma omp (parallel for) fails.
examples:
https://github.com/ARM-software/HPCG_for_Arm/blob/master/src/ComputeSYMGS.cpp#L84
https://github.com/ARM-software/HPCG_for_Arm/blob/master/src/ComputeDotProduct.cpp#L91