| Issue |
137870
|
| Summary |
Clang 21 crash when using __attribute__((alloc_size(2,1))) on variadic function declaration
|
| Labels |
clang
|
| Assignees |
|
| Reporter |
mariete1223
|
## Summary
Clang 21 crashes with a segmentation fault when compiling a variadic function declaration annotated with __attribute__((alloc_size(2,1))).
The compiler fails to check whether the arguments to the attribute are valid for a variadic function before trying to process them.
## Stack Dump
```
Stack dump:
0. Program arguments: /usr/local/bin/clang-21 -cc1 -triple x86_64-unknown-linux-gnu -emit-obj -dumpdir a- -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name prueba.cpp -mrelocation-model pic -pic-level 2 -pic-is-pie -mframe-pointer=none -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=/root -fcoverage-compilation-dir=/root -resource-dir /usr/local/lib/clang/21 -internal-isystem /usr/local/lib/clang/21/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/9/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O3 -std=c2x -ferror-limit 19 -fgnuc-version=4.2.1 -fskip-odr-check-in-gmf -fcolor-diagnostics -vectorize-loops -vectorize-slp -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/prueba-ee2b13.o -x c prueba.cpp
1. prueba.cpp:7:64: current parser token '{'
#0 0x0000564cefc1e18f llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/usr/local/bin/clang-21+0x3c4a18f)
#1 0x0000564cefc1bbd4 SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
#2 0x00007fd7c765f420 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14420)
#3 0x0000564cf223ca85 bool checkParamIsIntegerType<clang::ParsedAttr>(clang::Sema&, clang::Decl const*, clang::ParsedAttr const&, unsigned int) SemaDeclAttr.cpp:0:0
#4 0x0000564cf2243e56 handleAllocSizeAttr(clang::Sema&, clang::Decl*, clang::ParsedAttr const&) SemaDeclAttr.cpp:0:0
#5 0x0000564cf224edb6 ProcessDeclAttribute(clang::Sema&, clang::Scope*, clang::Decl*, clang::ParsedAttr const&, clang::Sema::ProcessDeclAttributeOptions const&) (.isra.0) SemaDeclAttr.cpp:0:0
#6 0x0000564cf22520f5 clang::Sema::ProcessDeclAttributes(clang::Scope*, clang::Decl*, clang::Declarator const&) (/usr/local/bin/clang-21+0x627e0f5)
#7 0x0000564cf220787c clang::Sema::ActOnFunctionDeclarator(clang::Scope*, clang::Declarator&, clang::DeclContext*, clang::TypeSourceInfo*, clang::LookupResult&, llvm::MutableArrayRef<clang::TemplateParameterList*>, bool&) (/usr/local/bin/clang-21+0x623387c)
#8 0x0000564cf220d114 clang::Sema::HandleDeclarator(clang::Scope*, clang::Declarator&, llvm::MutableArrayRef<clang::TemplateParameterList*>) (/usr/local/bin/clang-21+0x6239114)
#9 0x0000564cf220d93c clang::Sema::ActOnStartOfFunctionDef(clang::Scope*, clang::Declarator&, llvm::MutableArrayRef<clang::TemplateParameterList*>, clang::SkipBodyInfo*, clang::Sema::FnBodyKind) (/usr/local/bin/clang-21+0x623993c)
#10 0x0000564cf1e41db1 clang::Parser::ParseFunctionDefinition(clang::ParsingDeclarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::LateParsedAttrList*) (/usr/local/bin/clang-21+0x5e6ddb1)
#11 0x0000564cf1e8bf05 clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::Parser::ParsedTemplateInfo&, clang::SourceLocation*, clang::Parser::ForRangeInit*) (/usr/local/bin/clang-21+0x5eb7f05)
#12 0x0000564cf1e3a62d clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/usr/local/bin/clang-21+0x5e6662d)
#13 0x0000564cf1e3b16e clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/usr/local/bin/clang-21+0x5e6716e)
#14 0x0000564cf1e44d73 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/usr/local/bin/clang-21+0x5e70d73)
#15 0x0000564cf1e466a8 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/usr/local/bin/clang-21+0x5e726a8)
#16 0x0000564cf1e3462a clang::ParseAST(clang::Sema&, bool, bool) (/usr/local/bin/clang-21+0x5e6062a)
#17 0x0000564cf05a2e45 clang::CodeGenAction::ExecuteAction() (/usr/local/bin/clang-21+0x45cee45)
#18 0x0000564cf08879b8 clang::FrontendAction::Execute() (/usr/local/bin/clang-21+0x48b39b8)
#19 0x0000564cf0805d3b clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/usr/local/bin/clang-21+0x4831d3b)
#20 0x0000564cf0979c7b clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/usr/local/bin/clang-21+0x49a5c7b)
#21 0x0000564cece76f51 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/usr/local/bin/clang-21+0xea2f51)
#22 0x0000564cece6f5fd ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#23 0x0000564cece7299f clang_main(int, char**, llvm::ToolContext const&) (/usr/local/bin/clang-21+0xe9e99f)
#24 0x0000564cecd4530b main (/usr/local/bin/clang-21+0xd7130b)
#25 0x00007fd7c710d083 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x24083)
#26 0x0000564cece6f07e _start (/usr/local/bin/clang-21+0xe9b07e)
```
## Program
```
#include <stdlib.h>
#include <stdint.h>
typedef struct {
void *p;
size_t n;
} ptn_p;
void *__attribute__((alloc_size(2, 1))) malloc_x(size_t n,...) {
}
```
## To quickly reproduce
https://gcc.godbolt.org/z/WEqaqcGMb
![]()
_______________________________________________
llvm-bugs mailing list
llvm-bugs@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-bugs
