[clang] Crash from constexpr-evaluation of structured-binding variable #67690
Labels
clang:frontend
Language frontend issues, e.g. anything involving "Sema"
confirmed
Verified by a second party
crash
Prefer [crash-on-valid] or [crash-on-invalid]
Comments
hazohelet
added
clang:frontend
|
@llvm/issue-subscribers-clang-frontend
The use of `&c` at the end of the following code causes clang ICE.
using size_t = decltype(sizeof(0));
namespace std {
template <typename T> struct tuple_size;
template <size_t, typename> struct tuple_element;
} // namespace std
template <typename T> struct std::tuple_size<const T> : std::tuple_size<T> {};
template <size_t N, typename T> struct std::tuple_element<N, const T> {
typedef const typename std::tuple_element<N, T>::type type;
};
struct C {
template <int> int get() const;
};
template <> struct std::tuple_size<C> {
static const int value = 1;
};
template <> struct std::tuple_element<0, C> {
typedef int type;
};
template <const C *p> void f() {
const auto &[c] = *p;
&c;
}Live demo: https://godbolt.org/z/918oE41Ke clang++: /root/llvm-project/clang/lib/AST/ExprConstant.cpp:3381: bool evaluateVarDeclInit({anonymous}::EvalInfo&, const clang::Expr*, const clang::VarDecl*, {anonymous}::CallStackFrame*, unsigned int, clang::APValue*&):
Assertion `!VD->mightBeUsableInConstantExpressions(Info.Ctx)' 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: /opt/compiler-explorer/clang-assertions-trunk/bin/clang++ -gdwarf-4 -g -o /app/output.s -mllvm --x86-asm-syntax=intel -S --gcc-toolchain=/opt/compiler-explorer/gcc-snapshot -fcolor-diagnostics -fno-crash-diagnostics -std=c++2b <source>
1. <source>:25:5: current parser token ';'
2. <source>:23:32: parsing function body 'f'
3. <source>:23:32: in compound statement ('{}')
#<!-- -->0 0x0000000003708fb8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3708fb8)
#<!-- -->1 0x0000000003706c7c llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3706c7c)
#<!-- -->2 0x000000000364f8d8 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
#<!-- -->3 0x00007f76867d4420 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14420)
#<!-- -->4 0x00007f768629700b raise (/lib/x86_64-linux-gnu/libc.so.6+0x4300b)
#<!-- -->5 0x00007f7686276859 abort (/lib/x86_64-linux-gnu/libc.so.6+0x22859)
#<!-- -->6 0x00007f7686276729 (/lib/x86_64-linux-gnu/libc.so.6+0x22729)
#<!-- -->7 0x00007f7686287fd6 (/lib/x86_64-linux-gnu/libc.so.6+0x33fd6)
#<!-- -->8 0x0000000006f80225 (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6f80225)
#<!-- -->9 0x0000000006fa9b66 (anonymous namespace)::LValueExprEvaluator::VisitVarDecl(clang::Expr const*, clang::VarDecl const*) ExprConstant.cpp:0:0
#<!-- -->10 0x0000000006fe7e9b (anonymous namespace)::LValueExprEvaluator::VisitDeclRefExpr(clang::DeclRefExpr const*) ExprConstant.cpp:0:0
#<!-- -->11 0x0000000006fc4837 clang::StmtVisitorBase<llvm::make_const_ptr, (anonymous namespace)::LValueExprEvaluator, bool>::Visit(clang::Stmt const*) ExprConstant.cpp:0:0
#<!-- -->12 0x0000000006fe7eb6 (anonymous namespace)::LValueExprEvaluator::VisitDeclRefExpr(clang::DeclRefExpr const*) ExprConstant.cpp:0:0
#<!-- -->13 0x0000000006fc4837 clang::StmtVisitorBase<llvm::make_const_ptr, (anonymous namespace)::LValueExprEvaluator, bool>::Visit(clang::Stmt const*) ExprConstant.cpp:0:0
#<!-- -->14 0x0000000006fc5d8d EvaluateLValue(clang::Expr const*, (anonymous namespace)::LValue&, (anonymous namespace)::EvalInfo&, bool) ExprConstant.cpp:0:0
#<!-- -->15 0x0000000006f9a14e Evaluate(clang::APValue&, (anonymous namespace)::EvalInfo&, clang::Expr const*) ExprConstant.cpp:0:0
#<!-- -->16 0x0000000006fb8e42 EvaluateInPlace(clang::APValue&, (anonymous namespace)::EvalInfo&, (anonymous namespace)::LValue const&, clang::Expr const*, bool) ExprConstant.cpp:0:0
#<!-- -->17 0x0000000006ff4208 clang::Expr::EvaluateAsConstantExpr(clang::Expr::EvalResult&, clang::ASTContext const&, clang::Expr::ConstantExprKind) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6ff4208)
#<!-- -->18 0x0000000006eaf122 clang::computeDependence(clang::UnaryOperator*, clang::ASTContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6eaf122)
#<!-- -->19 0x0000000006f623f3 clang::UnaryOperator::Create(clang::ASTContext const&, clang::Expr*, clang::UnaryOperatorKind, clang::QualType, clang::ExprValueKind, clang::ExprObjectKind, clang::SourceLocation, bool, clang::FPOptionsOverride) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6f623f3)
#<!-- -->20 0x00000000063ffa0f clang::Sema::CreateBuiltinUnaryOp(clang::SourceLocation, clang::UnaryOperatorKind, clang::Expr*, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63ffa0f)
#<!-- -->21 0x00000000064004ed clang::Sema::BuildUnaryOp(clang::Scope*, clang::SourceLocation, clang::UnaryOperatorKind, clang::Expr*, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x64004ed)
#<!-- -->22 0x0000000005ed5bf9 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x5ed5bf9)
#<!-- -->23 0x0000000005ed7d8a clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x5ed7d8a)
#<!-- -->24 0x0000000005ed7f29 clang::Parser::ParseAssignmentExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x5ed7f29)
#<!-- -->25 0x0000000005edcc29 clang::Parser::ParseExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x5edcc29)
#<!-- -->26 0x0000000005f57dc7 clang::Parser::ParseExprStatement(clang::Parser::ParsedStmtContext) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x5f57dc7)
#<!-- -->27 0x0000000005f4e43d clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::ParsedAttributes&, clang::ParsedAttributes&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x5f4e43d)
#<!-- -->28 0x0000000005f4f278 clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x5f4f278)
#<!-- -->29 0x0000000005f501b9 clang::Parser::ParseCompoundStatementBody(bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x5f501b9)
#<!-- -->30 0x0000000005f51ada clang::Parser::ParseFunctionStatementBody(clang::Decl*, clang::Parser::ParseScope&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x5f51ada)
#<!-- -->31 0x0000000005e7f1c1 clang::Parser::ParseFunctionDefinition(clang::ParsingDeclarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::LateParsedAttrList*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x5e7f1c1)
#<!-- -->32 0x0000000005f6b520 clang::Parser::ParseSingleDeclarationAfterTemplate(clang::DeclaratorContext, clang::Parser::ParsedTemplateInfo const&, clang::ParsingDeclRAIIObject&, clang::SourceLocation&, clang::ParsedAttributes&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x5f6b520)
#<!-- -->33 0x0000000005f70a18 clang::Parser::ParseTemplateDeclarationOrSpecialization(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::AccessSpecifier) (.part.0) ParseTemplate.cpp:0:0
#<!-- -->34 0x0000000005f70cd3 clang::Parser::ParseDeclarationStartingWithTemplate(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x5f70cd3)
#<!-- -->35 0x0000000005eaea0b clang::Parser::ParseDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::ParsedAttributes&, clang::SourceLocation*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x5eaea0b)
#<!-- -->36 0x0000000005e79814 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x5e79814)
#<!-- -->37 0x0000000005e7a71d clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x5e7a71d)
#<!-- -->38 0x0000000005e6ea5a clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x5e6ea5a)
#<!-- -->39 0x00000000049724d8 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x49724d8)
#<!-- -->40 0x00000000041d6509 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x41d6509)
#<!-- -->41 0x00000000041571ee clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x41571ee)
#<!-- -->42 0x00000000042b584e clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x42b584e)
#<!-- -->43 0x0000000000bdcb46 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xbdcb46)
#<!-- -->44 0x0000000000bd440a ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#<!-- -->45 0x0000000003fb4a69 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) Job.cpp:0:0
#<!-- -->46 0x000000000364fd84 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x364fd84)
#<!-- -->47 0x0000000003fb505f clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const (.part.0) Job.cpp:0:0
#<!-- -->48 0x0000000003f7d3a5 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3f7d3a5)
#<!-- -->49 0x0000000003f7de0d clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3f7de0d)
#<!-- -->50 0x0000000003f85d35 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3f85d35)
#<!-- -->51 0x0000000000bd9fec clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xbd9fec)
#<!-- -->52 0x0000000000ad4d61 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xad4d61)
#<!-- -->53 0x00007f7686278083 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x24083)
#<!-- -->54 0x0000000000bd3eee _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xbd3eee) |
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Looks like it started in clang12: https://godbolt.org/z/n9z9P1fca Looks related to but not identical to: #53598 |
|
I reduced it to this: https://godbolt.org/z/3c5rzxorT struct C {
int x;
};
template <const C *p> void f() {
const auto &[c] = *p;
&c;
}and then the backtrace looks like: #53598 so I think these are probably the same problem but different ways of hitting it but not 💯 |
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llvm-project/clang/lib/AST/ExprConstant.cpp Lines 3375 to 3390 in 4b4d383 The comment here says "The DeclRefExpr is not value-dependent" - but it is: |
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So, this fixes the reproducer: diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 04a751f1b4d0..a3a9ccdab523 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -3306,6 +3306,8 @@ static bool HandleLValueComplexElement(EvalInfo &Info, const Expr *E,
static bool evaluateVarDeclInit(EvalInfo &Info, const Expr *E,
const VarDecl *VD, CallStackFrame *Frame,
unsigned Version, APValue *&Result) {
+ if (E->isValueDependent())
+ return false;
APValue::LValueBase Base(VD, Frame ? Frame->Index : 0, Version);
// If this is a local variable, dig out its value.
|
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How do we end up in |
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we aren't, this is in |
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@tbaederr are you going to submit a patch? |
tbaederr
added a commit
to tbaederr/llvm-project
that referenced
this issue
Oct 5, 2023
The Expression here migth be value dependent, which makes us run into an assertion later on. Just bail out early. Fixes llvm#67690
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The use of
&cat the end of the following code causes clang ICE.Live demo: https://godbolt.org/z/918oE41Ke
Backtrace:
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