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mpolacek opened this issue Sep 6, 2023 · 3 comments · Fixed by #66222
Closed

c++20: ICE trying to emit a call to an immediate function #65520

mpolacek opened this issue Sep 6, 2023 · 3 comments · Fixed by #66222
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clang:codegen IR generation bugs: mangling, exceptions, etc. confirmed Verified by a second party consteval C++20 consteval crash Prefer [crash-on-valid] or [crash-on-invalid]

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@mpolacek
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mpolacek commented Sep 6, 2023 •
edited by tbaederr
Loading 

consteval int bar (int i) { if (i != 1) throw 1; return 0; }

void
g ()
{
  int a1[bar(3)];
}

Using

$ xclang++ -v
clang version 18.0.0 (https://github.com/llvm/llvm-project.git 6258912880876edd44944e130aef01b33480168b)

results in:

$ xclang++ -c -std=c++20 ice1.C
xclang++: /home/mpolacek/src/llvm-project/clang/lib/CodeGen/CGExpr.cpp:5305: clang::CodeGen::RValue clang::CodeGen::CodeGenFunction::EmitCall(clang::QualType, const clang::CodeGen::CGCallee&, const clang::CallExpr*, clang::CodeGen::ReturnValueSlot, llvm::Value*): Assertion `(!isa_and_present<FunctionDecl>(TargetDecl) || !cast<FunctionDecl>(TargetDecl)->isImmediateFunction()) && "trying to emit a call to an immediate function"' failed.
PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.	Program arguments: xclang++ -c -std=c++20 ice1.C
1.	<eof> parser at end of file
2.	ice1.C:4:1: LLVM IR generation of declaration 'g'
3.	ice1.C:4:1: Generating code for declaration 'g'
 #0 0x0000000004529287 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /home/mpolacek/src/llvm-project/llvm/lib/Support/Unix/Signals.inc:723:22
 #1 0x0000000004529381 PrintStackTraceSignalHandler(void*) /home/mpolacek/src/llvm-project/llvm/lib/Support/Unix/Signals.inc:798:1
 #2 0x0000000004526e46 llvm::sys::RunSignalHandlers() /home/mpolacek/src/llvm-project/llvm/lib/Support/Signals.cpp:105:20
 #3 0x0000000004528b73 llvm::sys::CleanupOnSignal(unsigned long) /home/mpolacek/src/llvm-project/llvm/lib/Support/Unix/Signals.inc:367:31
 #4 0x0000000004460bf8 (anonymous namespace)::CrashRecoveryContextImpl::HandleCrash(int, unsigned long) /home/mpolacek/src/llvm-project/llvm/lib/Support/CrashRecoveryContext.cpp:73:5
 #5 0x0000000004461087 CrashRecoverySignalHandler(int) /home/mpolacek/src/llvm-project/llvm/lib/Support/CrashRecoveryContext.cpp:391:1
 #6 0x00007ff6ba85fb20 __restore_rt (/lib64/libc.so.6+0x3cb20)
 #7 0x00007ff6ba8afe8c __pthread_kill_implementation /usr/src/debug/glibc-2.36-11.fc37.x86_64/nptl/pthread_kill.c:44:76
 #8 0x00007ff6ba85fa76 gsignal /usr/src/debug/glibc-2.36-11.fc37.x86_64/signal/../sysdeps/posix/raise.c:27:6
 #9 0x00007ff6ba8497fc abort /usr/src/debug/glibc-2.36-11.fc37.x86_64/stdlib/abort.c:81:7
#10 0x00007ff6ba84971b _nl_load_domain.cold /usr/src/debug/glibc-2.36-11.fc37.x86_64/intl/loadmsgcat.c:1177:9
#11 0x00007ff6ba858656 (/lib64/libc.so.6+0x35656)
#12 0x0000000004fd2591 clang::CodeGen::CodeGenFunction::EmitCall(clang::QualType, clang::CodeGen::CGCallee const&, clang::CallExpr const*, clang::CodeGen::ReturnValueSlot, llvm::Value*) /home/mpolacek/src/llvm-project/clang/lib/CodeGen/CGExpr.cpp:5309:26
#13 0x0000000004fd0624 clang::CodeGen::CodeGenFunction::EmitCallExpr(clang::CallExpr const*, clang::CodeGen::ReturnValueSlot) /home/mpolacek/src/llvm-project/clang/lib/CodeGen/CGExpr.cpp:4993:18
#14 0x000000000500ece0 (anonymous namespace)::ScalarExprEmitter::VisitCallExpr(clang::CallExpr const*) /home/mpolacek/src/llvm-project/clang/lib/CodeGen/CGExprScalar.cpp:580:32
#15 0x000000000502a452 clang::StmtVisitorBase<std::add_pointer, (anonymous namespace)::ScalarExprEmitter, llvm::Value*>::Visit(clang::Stmt*) /home/mpolacek/src/llvm-project/build/tools/clang/include/clang/AST/StmtNodes.inc:949:1
#16 0x000000000500de9c (anonymous namespace)::ScalarExprEmitter::Visit(clang::Expr*) /home/mpolacek/src/llvm-project/clang/lib/CodeGen/CGExprScalar.cpp:407:57
#17 0x000000000502765e clang::CodeGen::CodeGenFunction::EmitScalarExpr(clang::Expr const*, bool) /home/mpolacek/src/llvm-project/clang/lib/CodeGen/CGExprScalar.cpp:5098:1
#18 0x0000000004abb2e6 clang::CodeGen::CodeGenFunction::EmitVariablyModifiedType(clang::QualType) /home/mpolacek/src/llvm-project/clang/lib/CodeGen/CodeGenFunction.cpp:2317:54
#19 0x0000000004f8a2e7 clang::CodeGen::CodeGenFunction::EmitAutoVarAlloca(clang::VarDecl const&) /home/mpolacek/src/llvm-project/clang/lib/CodeGen/CGDecl.cpp:1458:26
#20 0x0000000004f8984b clang::CodeGen::CodeGenFunction::EmitAutoVarDecl(clang::VarDecl const&) /home/mpolacek/src/llvm-project/clang/lib/CodeGen/CGDecl.cpp:1345:18
#21 0x0000000004f83ebb clang::CodeGen::CodeGenFunction::EmitVarDecl(clang::VarDecl const&) /home/mpolacek/src/llvm-project/clang/lib/CodeGen/CGDecl.cpp:218:27
#22 0x0000000004f83bb0 clang::CodeGen::CodeGenFunction::EmitDecl(clang::Decl const&) /home/mpolacek/src/llvm-project/clang/lib/CodeGen/CGDecl.cpp:164:47
#23 0x00000000049f93a9 clang::CodeGen::CodeGenFunction::EmitDeclStmt(clang::DeclStmt const&) /home/mpolacek/src/llvm-project/clang/lib/CodeGen/CGStmt.cpp:1394:3
#24 0x00000000049f498e clang::CodeGen::CodeGenFunction::EmitSimpleStmt(clang::Stmt const*, llvm::ArrayRef<clang::Attr const*>) /home/mpolacek/src/llvm-project/clang/lib/CodeGen/CGStmt.cpp:453:5
#25 0x00000000049f3922 clang::CodeGen::CodeGenFunction::EmitStmt(clang::Stmt const*, llvm::ArrayRef<clang::Attr const*>) /home/mpolacek/src/llvm-project/clang/lib/CodeGen/CGStmt.cpp:61:3
#26 0x00000000049f4f12 clang::CodeGen::CodeGenFunction::EmitCompoundStmtWithoutScope(clang::CompoundStmt const&, bool, clang::CodeGen::AggValueSlot) /home/mpolacek/src/llvm-project/clang/lib/CodeGen/CGStmt.cpp:507:3
#27 0x0000000004ab732c clang::CodeGen::CodeGenFunction::EmitFunctionBody(clang::Stmt const*) /home/mpolacek/src/llvm-project/clang/lib/CodeGen/CodeGenFunction.cpp:1262:33
#28 0x0000000004ab82ab clang::CodeGen::CodeGenFunction::GenerateCode(clang::GlobalDecl, llvm::Function*, clang::CodeGen::CGFunctionInfo const&) /home/mpolacek/src/llvm-project/clang/lib/CodeGen/CodeGenFunction.cpp:1481:21
#29 0x0000000004ae98d3 clang::CodeGen::CodeGenModule::EmitGlobalFunctionDefinition(clang::GlobalDecl, llvm::GlobalValue*) /home/mpolacek/src/llvm-project/clang/lib/CodeGen/CodeGenModule.cpp:5657:3
#30 0x0000000004ae228c clang::CodeGen::CodeGenModule::EmitGlobalDefinition(clang::GlobalDecl, llvm::GlobalValue*) /home/mpolacek/src/llvm-project/clang/lib/CodeGen/CodeGenModule.cpp:3922:47
#31 0x0000000004ae1232 clang::CodeGen::CodeGenModule::EmitGlobal(clang::GlobalDecl) /home/mpolacek/src/llvm-project/clang/lib/CodeGen/CodeGenModule.cpp:3663:27
#32 0x0000000004aedd0a clang::CodeGen::CodeGenModule::EmitTopLevelDecl(clang::Decl*) /home/mpolacek/src/llvm-project/clang/lib/CodeGen/CodeGenModule.cpp:6561:37
#33 0x0000000005e67523 (anonymous namespace)::CodeGeneratorImpl::HandleTopLevelDecl(clang::DeclGroupRef) /home/mpolacek/src/llvm-project/clang/lib/CodeGen/ModuleBuilder.cpp:189:7
#34 0x0000000005e5e580 clang::BackendConsumer::HandleTopLevelDecl(clang::DeclGroupRef) /home/mpolacek/src/llvm-project/clang/lib/CodeGen/CodeGenAction.cpp:237:11
#35 0x0000000007ec7cc4 clang::ParseAST(clang::Sema&, bool, bool) /home/mpolacek/src/llvm-project/clang/lib/Parse/ParseAST.cpp:167:20
#36 0x000000000543bda6 clang::ASTFrontendAction::ExecuteAction() /home/mpolacek/src/llvm-project/clang/lib/Frontend/FrontendAction.cpp:1178:11
#37 0x0000000005e5bb09 clang::CodeGenAction::ExecuteAction() /home/mpolacek/src/llvm-project/clang/lib/CodeGen/CodeGenAction.cpp:1208:5
#38 0x000000000543b6f7 clang::FrontendAction::Execute() /home/mpolacek/src/llvm-project/clang/lib/Frontend/FrontendAction.cpp:1068:38
#39 0x00000000053705ae clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) /home/mpolacek/src/llvm-project/clang/lib/Frontend/CompilerInstance.cpp:1054:42
#40 0x00000000055ce71a clang::ExecuteCompilerInvocation(clang::CompilerInstance*) /home/mpolacek/src/llvm-project/clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp:272:38
#41 0x0000000000d41ca2 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) /home/mpolacek/src/llvm-project/clang/tools/driver/cc1_main.cpp:254:40
#42 0x0000000000d32de7 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) /home/mpolacek/src/llvm-project/clang/tools/driver/driver.cpp:366:20
#43 0x0000000000d32fd1 clang_main(int, char**, llvm::ToolContext const&)::'lambda'(llvm::SmallVectorImpl<char const*>&)::operator()(llvm::SmallVectorImpl<char const*>&) const /home/mpolacek/src/llvm-project/clang/tools/driver/driver.cpp:507:5
#44 0x0000000000d345bb int llvm::function_ref<int (llvm::SmallVectorImpl<char const*>&)>::callback_fn<clang_main(int, char**, llvm::ToolContext const&)::'lambda'(llvm::SmallVectorImpl<char const*>&)>(long, llvm::SmallVectorImpl<char const*>&) /home/mpolacek/src/llvm-project/llvm/include/llvm/ADT/STLFunctionalExtras.h:47:3
#45 0x00000000051f475d llvm::function_ref<int (llvm::SmallVectorImpl<char const*>&)>::operator()(llvm::SmallVectorImpl<char const*>&) const /home/mpolacek/src/llvm-project/llvm/include/llvm/ADT/STLFunctionalExtras.h:69:3
#46 0x00000000051f35e8 clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const::'lambda'()::operator()() const /home/mpolacek/src/llvm-project/clang/lib/Driver/Job.cpp:440:32
#47 0x00000000051f3a0a 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::'lambda'()>(long) /home/mpolacek/src/llvm-project/llvm/include/llvm/ADT/STLFunctionalExtras.h:46:40
#48 0x000000000331120e llvm::function_ref<void ()>::operator()() const /home/mpolacek/src/llvm-project/llvm/include/llvm/ADT/STLFunctionalExtras.h:68:62
#49 0x000000000446124f llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) /home/mpolacek/src/llvm-project/llvm/lib/Support/CrashRecoveryContext.cpp:427:10
#50 0x00000000051f37d4 clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const /home/mpolacek/src/llvm-project/clang/lib/Driver/Job.cpp:440:7
#51 0x0000000005196feb clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const /home/mpolacek/src/llvm-project/clang/lib/Driver/Compilation.cpp:199:22
#52 0x0000000005197317 clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const /home/mpolacek/src/llvm-project/clang/lib/Driver/Compilation.cpp:253:62
#53 0x00000000051a95dc clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) /home/mpolacek/src/llvm-project/clang/lib/Driver/Driver.cpp:1883:28
#54 0x0000000000d34167 clang_main(int, char**, llvm::ToolContext const&) /home/mpolacek/src/llvm-project/clang/tools/driver/driver.cpp:542:39
#55 0x0000000000d653ee main /home/mpolacek/src/llvm-project/build/tools/clang/tools/driver/clang-driver.cpp:15:58
#56 0x00007ff6ba84a510 __libc_start_call_main /usr/src/debug/glibc-2.36-11.fc37.x86_64/csu/../sysdeps/nptl/libc_start_call_main.h:74:3
#57 0x00007ff6ba84a5c9 call_init /usr/src/debug/glibc-2.36-11.fc37.x86_64/csu/../csu/libc-start.c:128:20
#58 0x00007ff6ba84a5c9 __libc_start_main@GLIBC_2.2.5 /usr/src/debug/glibc-2.36-11.fc37.x86_64/csu/../csu/libc-start.c:347:5
#59 0x0000000000d313a5 _start (/home/mpolacek/src/llvm-project/build/bin/clang-12+0xd313a5)
xclang++: error: clang frontend command failed with exit code 134 (use -v to see invocation)
clang version 18.0.0 (https://github.com/llvm/llvm-project.git 6258912880876edd44944e130aef01b33480168b)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/mpolacek/bin
xclang++: note: diagnostic msg:
@EugeneZelenko EugeneZelenko added clang:codegen IR generation bugs: mangling, exceptions, etc. crash Prefer [crash-on-valid] or [crash-on-invalid] and removed new issue labels Sep 6, 2023
@llvmbot
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llvmbot commented Sep 6, 2023

@llvm/issue-subscribers-clang-codegen

@cor3ntin cor3ntin added the consteval C++20 consteval label Sep 6, 2023
@cor3ntin
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cor3ntin commented Sep 6, 2023

confirmed
https://compiler-explorer.com/z/5hq4n5KGM

@cor3ntin cor3ntin added the confirmed Verified by a second party label Sep 6, 2023
@tbaederr
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tbaederr commented Sep 7, 2023 •
edited
Loading

We try to emit this as VLA (because the consteval function isn't valid).

Not sure if there's an existing mechanism for a "fatal" error in this context.

@cor3ntin cor3ntin mentioned this issue Sep 13, 2023
Merged
cor3ntin added a commit to cor3ntin/llvm-project that referenced this issue Oct 5, 2023
@cor3ntin
[Clang] Handle consteval expression in array bounds expressions
dc95c83 
The bounds of a c++ array is a _constant-expression_.
And in C++ it is also a constant expression.

But we also support VLAs, ie arrays with non-constant bounds.

We need to take care to handle the case of a consteval function
(which are specified to be only immediately called in
non-constant contexts) that appear in arrays bounds.

This introduces `Sema::isAlwayConstantEvaluatedContext`,
and a flag in ExpressionEvaluationContextRecord, such that
immediate functions in array bounds are always immediately invoked.

Sema had both `isConstantEvaluatedContext` and
`isConstantEvaluated`, so I took the opportunity to cleanup that.

The change in `TimeProfilerTest.cpp` is an unfortunate
manifestation of the problem that llvm#66203 seeks to address.

Fixes llvm#65520
cor3ntin added a commit that referenced this issue Oct 5, 2023
@cor3ntin
[Clang] Handle consteval expression in array bounds expressions (#66222)
c72d3a0 
The bounds of a c++ array is a _constant-expression_. And in C++ it is
also a constant expression.

But we also support VLAs, ie arrays with non-constant bounds.

We need to take care to handle the case of a consteval function (which
are specified to be only immediately called in non-constant contexts)
that appear in arrays bounds.

This introduces `Sema::isAlwayConstantEvaluatedContext`, and a flag in
ExpressionEvaluationContextRecord, such that immediate functions in
array bounds are always immediately invoked.

Sema had both `isConstantEvaluatedContext` and
`isConstantEvaluated`, so I took the opportunity to cleanup that.

The change in `TimeProfilerTest.cpp` is an unfortunate manifestation of
the problem that #66203 seeks to address.

Fixes #65520
@AZero13 AZero13 mentioned this issue May 26, 2025
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[Clang] Handle consteval expression in array bounds expressions cor3ntin/llvm-project
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@cor3ntin @EugeneZelenko @mpolacek @tbaederr @llvmbot