| Issue |
170451
|
| Summary |
Clang ICE when dereferencing volatile void pointer in statement _expression_
|
| Labels |
clang
|
| Assignees |
|
| Reporter |
AbyssStaror
|
### Link for quick verification: https://godbolt.org/z/7bf48cnbv
```c
int main() {
__int128 z = __extension__ ({
union {
unsigned long u[2];
__int128 i;
} tmp;
*(volatile void*)(&tmp.i); // Problematic line
});
return 0;
}
```
Clang triggers an internal compiler error (ICE) with `UNREACHABLE executed` when attempting to compile code that dereferences a `volatile void*pointer` within a statement _expression_. The crash occurs during the implicit cast from glvalue to prvalue.
## Stack dump:
```
/workspace/exps/featurefuzz/generate_feature_fine_tuning_qwen_4b_1_exp/cases/7467.fuzz:13:7: warning: ISO C does not
allow indirection on operand of type 'volatile void *' [-Wvoid-ptr-dereference]
13 | *(volatile void *)&tmp; });
| ^~~~~~~~~~~~~~~~~~~~~~
can't implicitly cast glvalue to prvalue with this cast kind: NoOp
UNREACHABLE executed at /workspace/install/llvm/src/llvm-project/clang/lib/Sema/Sema.cpp:765!
Stack dump:
0. Program arguments: /workspace/install/llvm/build_21.1.4/bin/clang-21 -cc1 -triple x86_64-unknown-linux-gnu -emit-obj -dumpdir a- -disable-free -clear-ast-before-backend -main-file-name 7467.fuzz -mrelocation-model pic -pic-level 2 -pic-is-pie -mframe-pointer=all -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fdebug-compilation-dir=/workspace/exps -fcoverage-compilation-dir=/workspace/exps -resource-dir /workspace/install/llvm/build_21.1.4/lib/clang/21 -internal-isystem /workspace/install/llvm/build_21.1.4/lib/clang/21/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/13/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -ferror-limit 19 -fmessage-length=137 -fgnuc-version=4.2.1 -fskip-odr-check-in-gmf -fcolor-diagnostics -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/7467-c69d83.o -x c /workspace/exps/featurefuzz/generate_feature_fine_tuning_qwen_4b_1_exp/cases/7467.fuzz
1. /workspace/exps/featurefuzz/generate_feature_fine_tuning_qwen_4b_1_exp/cases/7467.fuzz:13:31: current parser token '}'
2. /workspace/exps/featurefuzz/generate_feature_fine_tuning_qwen_4b_1_exp/cases/7467.fuzz:7:12: parsing function body 'main'
3. /workspace/exps/featurefuzz/generate_feature_fine_tuning_qwen_4b_1_exp/cases/7467.fuzz:7:12: in compound statement ('{}')
4. /workspace/exps/featurefuzz/generate_feature_fine_tuning_qwen_4b_1_exp/cases/7467.fuzz:9:33: in compound statement ('{}')
#0 0x0000653223aaac2a llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0x9691c2a)
#1 0x0000653223aab457 PrintStackTraceSignalHandler(void*) Signals.cpp:0:0
#2 0x0000653223aa4f57 llvm::sys::RunSignalHandlers() (/workspace/install/llvm/build_21.1.4/bin/clang-21+0x968bf57)
#3 0x0000653223aa51c7 SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
#4 0x00007bb4b8da0330 (/lib/x86_64-linux-gnu/libc.so.6+0x45330)
#5 0x00007bb4b8df9b2c __pthread_kill_implementation ./nptl/pthread_kill.c:44:76
#6 0x00007bb4b8df9b2c __pthread_kill_internal ./nptl/pthread_kill.c:78:10
#7 0x00007bb4b8df9b2c pthread_kill ./nptl/pthread_kill.c:89:10
#8 0x00007bb4b8da027e raise ./signal/../sysdeps/posix/raise.c:27:6
#9 0x00007bb4b8d838ff abort ./stdlib/abort.c:81:7
#10 0x00006532239a26de llvm::llvm_unreachable_internal(char const*, char const*, unsigned int) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0x95896de)
#11 0x00006532271df5f4 clang::Sema::ImpCastExprToType(clang::Expr*, clang::QualType, clang::CastKind, clang::ExprValueKind, llvm::SmallVector<clang::CXXBaseSpecifier*, 4u> const*, clang::CheckedConversionKind) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xcdc65f4)
#12 0x0000653227768ac8 clang::Sema::CheckSingleAssignmentConstraints(clang::QualType, clang::ActionResult<clang::Expr*, true>&, bool, bool, bool) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xd34fac8)
#13 0x000065322794e51b clang::InitializationSequence::Perform(clang::Sema&, clang::InitializedEntity const&, clang::InitializationKind const&, llvm::MutableArrayRef<clang::Expr*>, clang::QualType*) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xd53551b)
#14 0x0000653227951b54 clang::Sema::PerformCopyInitialization(clang::InitializedEntity const&, clang::SourceLocation, clang::ActionResult<clang::Expr*, true>, bool, bool) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xd538b54)
#15 0x00006532277492ba clang::Sema::ActOnStmtExprResult(clang::ActionResult<clang::Expr*, true>) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xd3302ba)
#16 0x00006532270f104f clang::Parser::handleExprStmt(clang::ActionResult<clang::Expr*, true>, clang::Parser::ParsedStmtContext) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xccd804f)
#17 0x00006532270f7353 clang::Parser::ParseExprStatement(clang::Parser::ParsedStmtContext) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xccde353)
#18 0x00006532270f9487 clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector<clang::Stmt*, 24u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::ParsedAttributes&, clang::ParsedAttributes&) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xcce0487)
#19 0x00006532270fa099 clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector<clang::Stmt*, 24u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xcce1099)
#20 0x00006532270fbe9e clang::Parser::ParseCompoundStatementBody(bool) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xcce2e9e)
#21 0x00006532270fc7d0 void llvm::function_ref<void ()>::callback_fn<clang::Parser::ParseCompoundStatement(bool, unsigned int)::'lambda'()>(long) ParseStmt.cpp:0:0
#22 0x00006532294be42b clang::StackExhaustionHandler::runWithSufficientStackSpace(clang::SourceLocation, llvm::function_ref<void ()>) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xf0a542b)
#23 0x00006532270efe0e clang::Parser::ParseCompoundStatement(bool, unsigned int) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xccd6e0e)
#24 0x00006532270efe9e clang::Parser::ParseCompoundStatement(bool) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xccd6e9e)
#25 0x0000653227045e31 clang::Parser::ParseParenExpression(clang::ParenParseOption&, bool, clang::ParenExprKind, clang::TypoCorrectionTypeBehavior, clang::OpaquePtr<clang::QualType>&, clang::SourceLocation&) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xcc2ce31)
#26 0x000065322703a2da clang::Parser::ParseCastExpression(clang::CastParseKind, bool, bool&, clang::TypoCorrectionTypeBehavior, bool, bool*) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xcc212da)
#27 0x000065322703d0d1 clang::Parser::ParseCastExpression(clang::CastParseKind, bool, clang::TypoCorrectionTypeBehavior, bool, bool*) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xcc240d1)
#28 0x000065322703aa77 clang::Parser::ParseCastExpression(clang::CastParseKind, bool, bool&, clang::TypoCorrectionTypeBehavior, bool, bool*) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xcc21a77)
#29 0x000065322703d0d1 clang::Parser::ParseCastExpression(clang::CastParseKind, bool, clang::TypoCorrectionTypeBehavior, bool, bool*) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xcc240d1)
#30 0x000065322703d194 clang::Parser::ParseAssignmentExpression(clang::TypoCorrectionTypeBehavior) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xcc24194)
#31 0x0000653226fd79f6 clang::Parser::ParseDeclarationAfterDeclaratorAndAttributes(clang::Declarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::ForRangeInit*) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xcbbe9f6)
#32 0x0000653226ff8d1b clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::Parser::ParsedTemplateInfo&, clang::SourceLocation*, clang::Parser::ForRangeInit*) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xcbdfd1b)
#33 0x0000653226ffaa1f clang::Parser::ParseSimpleDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::ParsedAttributes&, bool, clang::Parser::ForRangeInit*, clang::SourceLocation*) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xcbe1a1f)
#34 0x0000653226ffb069 clang::Parser::ParseDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::ParsedAttributes&, clang::SourceLocation*) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xcbe2069)
#35 0x00006532270f946c clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector<clang::Stmt*, 24u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::ParsedAttributes&, clang::ParsedAttributes&) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xcce046c)
#36 0x00006532270fa099 clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector<clang::Stmt*, 24u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xcce1099)
#37 0x00006532270fbe9e clang::Parser::ParseCompoundStatementBody(bool) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xcce2e9e)
#38 0x00006532270fc8c2 clang::Parser::ParseFunctionStatementBody(clang::Decl*, clang::Parser::ParseScope&) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xcce38c2)
#39 0x0000653226fa0337 clang::Parser::ParseFunctionDefinition(clang::ParsingDeclarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::LateParsedAttrList*) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xcb87337)
#40 0x0000653226ff9d18 clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::Parser::ParsedTemplateInfo&, clang::SourceLocation*, clang::Parser::ForRangeInit*) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xcbe0d18)
#41 0x0000653226f96307 clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xcb7d307)
#42 0x0000653226f96e9e clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xcb7de9e)
#43 0x0000653226fa2f98 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xcb89f98)
#44 0x0000653226fa459d clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xcb8b59d)
#45 0x0000653226f8a9d0 clang::ParseAST(clang::Sema&, bool, bool) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xcb719d0)
#46 0x0000653224cd292b clang::ASTFrontendAction::ExecuteAction() (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xa8b992b)
#47 0x00006532248c0360 clang::CodeGenAction::ExecuteAction() (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xa4a7360)
#48 0x0000653224cda9cf clang::FrontendAction::Execute() (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xa8c19cf)
#49 0x0000653224c20f46 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xa807f46)
#50 0x0000653224e62f7b clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0xaa49f7b)
#51 0x000065321ebd1523 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0x47b8523)
#52 0x000065321ebc1c58 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#53 0x000065321ebc7b28 clang_main(int, char**, llvm::ToolContext const&) (/workspace/install/llvm/build_21.1.4/bin/clang-21+0x47aeb28)
#54 0x000065321ea22b4a main (/workspace/install/llvm/build_21.1.4/bin/clang-21+0x4609b4a)
#55 0x00007bb4b8d851ca __libc_start_call_main ./csu/../sysdeps/nptl/libc_start_call_main.h:74:3
#56 0x00007bb4b8d8528b call_init ./csu/../csu/libc-start.c:128:20
#57 0x00007bb4b8d8528b __libc_start_main ./csu/../csu/libc-start.c:347:5
#58 0x000065321ebbff55 _start (/workspace/install/llvm/build_21.1.4/bin/clang-21+0x47a6f55)
clang: error: unable to execute command: Aborted (core dumped)
```
## Clang version:
```
clang version 21.1.4 (https://github.com/llvm/llvm-project.git 222fc11f2b8f25f6a0f4976272ef1bb7bf49521d)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /workspace/install/llvm/build_21.1.4/bin
Build config: +assertions
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/13
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/13
Candidate multilib: .;@m64
Selected multilib: .;@m64
```
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