Clang frontend C++ crash when __builtin_dump_struct is used on pointer to undefined type

[mentlerd]

https://godbolt.org/z/fYs6ffrPT

#include <stdio.h>

struct Undefined;

struct Defined {
    Undefined* undef;
};

int main() {
    Undefined* value = nullptr;

    __builtin_dump_struct(value, printf);
    return 0;
}

Compiling this program crashes the clang frontend. Replacing the type of value with Defined emits correct code.

[mentlerd]

Assertion:

clang++: /root/llvm-project/clang/include/clang/AST/DeclCXX.h:452: clang::CXXRecordDecl::DefinitionData& clang::CXXRecordDecl::data() const: Assertion `DD && "queried property of class with no definition"' failed.

Backtrace:

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 -emit-llvm -Xclang -disable-llvm-passes <source>
1.	<source>:13:40: current parser token ')'
2.	<source>:10:12: parsing function body 'main'
3.	<source>:10:12: in compound statement ('{}')
 #0 0x000055b00cd5191f llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3c5291f)
 #1 0x000055b00cd4f68c llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3c5068c)
 #2 0x000055b00cc99d78 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x00007f88ad6a0420 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14420)
 #4 0x00007f88ad16d00b raise (/lib/x86_64-linux-gnu/libc.so.6+0x4300b)
 #5 0x00007f88ad14c859 abort (/lib/x86_64-linux-gnu/libc.so.6+0x22859)
 #6 0x00007f88ad14c729 (/lib/x86_64-linux-gnu/libc.so.6+0x22729)
 #7 0x00007f88ad15dfd6 (/lib/x86_64-linux-gnu/libc.so.6+0x33fd6)
 #8 0x000055b00cf9079a clang::CXXRecordDecl::data() const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3e9179a)
 #9 0x000055b00f69d63e (anonymous namespace)::BuiltinDumpStructGenerator::dumpRecordValue(clang::RecordDecl const*, clang::Expr*, clang::Expr*, unsigned int) SemaChecking.cpp:0:0
#10 0x000055b00f69ee44 (anonymous namespace)::BuiltinDumpStructGenerator::dumpUnnamedRecord(clang::RecordDecl const*, clang::Expr*, unsigned int) SemaChecking.cpp:0:0
#11 0x000055b00f6dbcb2 SemaBuiltinDumpStruct(clang::Sema&, clang::CallExpr*) SemaChecking.cpp:0:0
#12 0x000055b00f6e8423 clang::Sema::CheckBuiltinFunctionCall(clang::FunctionDecl*, unsigned int, clang::CallExpr*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x65e9423)
#13 0x000055b00fa8534f clang::Sema::BuildResolvedCallExpr(clang::Expr*, clang::NamedDecl*, clang::SourceLocation, llvm::ArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, bool, clang::CallExpr::ADLCallKind) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x698634f)
#14 0x000055b00fa80806 clang::Sema::BuildCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6981806)
#15 0x000055b00fa865cb clang::Sema::ActOnCallExpr(clang::Scope*, clang::Expr*, clang::SourceLocation, llvm::MutableArrayRef<clang::Expr*>, clang::SourceLocation, clang::Expr*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x69875cb)
#16 0x000055b00f531eea clang::Parser::ParsePostfixExpressionSuffix(clang::ActionResult<clang::Expr*, true>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x6432eea)
#17 0x000055b00f529fd7 clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x642afd7)
#18 0x000055b00f52d0eb clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, clang::Parser::TypeCastState, bool, bool*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x642e0eb)
#19 0x000055b00f52d19d clang::Parser::ParseAssignmentExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x642e19d)
#20 0x000055b00f5314dd clang::Parser::ParseExpression(clang::Parser::TypeCastState) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x64324dd)
#21 0x000055b00f5af690 clang::Parser::ParseExprStatement(clang::Parser::ParsedStmtContext) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x64b0690)
#22 0x000055b00f5a59b3 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+++0x64a69b3)
#23 0x000055b00f5a68b1 clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x64a78b1)
#24 0x000055b00f5a78a9 clang::Parser::ParseCompoundStatementBody(bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x64a88a9)
#25 0x000055b00f5a925a clang::Parser::ParseFunctionStatementBody(clang::Decl*, clang::Parser::ParseScope&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x64aa25a)
#26 0x000055b00f4d4151 clang::Parser::ParseFunctionDefinition(clang::ParsingDeclarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::LateParsedAttrList*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63d5151)
#27 0x000055b00f4fb060 clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::SourceLocation*, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63fc060)
#28 0x000055b00f4c79f1 clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63c89f1)
#29 0x000055b00f4c82af clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (.part.0) Parser.cpp:0:0
#30 0x000055b00f4cec51 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63cfc51)
#31 0x000055b00f4cf5c6 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63d05c6)
#32 0x000055b00f4c336a clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x63c436a)
#33 0x000055b00dfc7d68 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4ec8d68)
#34 0x000055b00d812779 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4713779)
#35 0x000055b00d7980c6 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x46990c6)
#36 0x000055b00d8f6e96 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x47f7e96)
#37 0x000055b00a1f502d cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x10f602d)
#38 0x000055b00a1f0d2a ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#39 0x000055b00d5f87cd 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
#40 0x000055b00cc9a280 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3b9b280)
#41 0x000055b00d5f8def 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
#42 0x000055b00d5bff5c clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x44c0f5c)
#43 0x000055b00d5c09ed 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+++0x44c19ed)
#44 0x000055b00d5c8acd clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x44c9acd)
#45 0x000055b00a1f328a clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x10f428a)
#46 0x000055b00a0f95a5 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xffa5a5)
#47 0x00007f88ad14e083 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x24083)
#48 0x000055b00a1ebb0e _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x10ecb0e)

[llvmbot]

@llvm/issue-subscribers-clang-frontend

[zyn0217]

Note Clang 14 gives error:

<source>:13:34: error: passing 'int (const char *__restrict, ...)' to parameter of incompatible type 'int (*)(const char *, ...)': type mismatch at 2nd parameter ('int (const char *__restrict, ...)' vs 'int (*)(const char *, ...)')
    __builtin_dump_struct(value, printf);
                                 ^

[zyn0217]

We're missing a checking CXXRD->hasDefinition() here.

llvm-project/clang/lib/Sema/SemaChecking.cpp

Lines 574 to 576 in 86f564e

	// Dump each base class, regardless of whether they're aggregates.
	if (const auto *CXXRD = dyn_cast<CXXRecordDecl>(RD)) {
	for (const auto &Base : CXXRD->bases()) {

But I'm not sure if dumping an incomplete type is as expected. CC @zygoloid

[zyn0217]

Link to the PR. This is a bonus fix while I'm altering other stuff inside the __builtin_dump_struct.