[PATCH] D154503: [Sema] Fix handling of functions that hide classes

Aaron Ballman via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Thu Aug 10 04:55:59 PDT 2023 

aaron.ballman added a comment.

In D154503#4576393 <https://reviews.llvm.org/D154503#4576393>, @kadircet wrote:

> Hi!
>
> After this patch clang seems to be crashing on:
>
>   class a {
>     static c a;
>     void b(){a};
>   };
>
> with stack trace and assertion error:
>
>   $ ~/repos/llvm/build/bin/clang -xc++ repro.cc
>   repro.cc:2:10: error: unknown type name 'c'
>       2 |   static c a;
>         |          ^
>   repro.cc:2:12: error: member 'a' has the same name as its class
>       2 |   static c a;
>         |            ^
>   clang-17: /usr/local/google/home/kadircet/repos/llvm/clang/lib/Sema/SemaLookup.cpp:333: bool clang::LookupResult::checkDebugAssumptions() const: Assertion `ResultKind != Found || Decls.size() == 1' 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: /usr/local/google/home/kadircet/repos/llvm/build/bin/clang-17 -cc1 -triple x86_64-unknown-linux-gnu -emit-obj -mrelax-all -dumpdir a- -disable-free -clear-ast-before-backend -main-file-name repro.cc -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 -fcoverage-compilation-dir=/usr/local/google/home/kadircet/repos/tmp/new_crasher -resource-dir /usr/local/google/home/kadircet/repos/llvm/build/lib/clang/18 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/12/../../../../include/c++/12 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/12/../../../../include/x86_64-linux-gnu/c++/12 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/12/../../../../include/c++/12/backward -internal-isystem /usr/local/google/home/kadircet/repos/llvm/build/lib/clang/18/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/12/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -fdeprecated-macro -fdebug-compilation-dir=/usr/local/google/home/kadircet/repos/tmp/new_crasher -ferror-limit 19 -fgnuc-version=4.2.1 -fcxx-exceptions -fexceptions -fcolor-diagnostics -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/repro-aa9901.o -x c++ repro.cc
>   1.      repro.cc:3:12: current parser token 'a'
>   2.      repro.cc:1:1: parsing struct/union/class body 'a'
>   3.      repro.cc:3:11: parsing function body 'a::b'
>   4.      repro.cc:3:11: in compound statement ('{}')
>    #0 0x000000000746e327 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /usr/local/google/home/kadircet/repos/llvm/llvm/lib/Support/Unix/Signals.inc:602:13
>    #1 0x000000000746c0ae llvm::sys::RunSignalHandlers() /usr/local/google/home/kadircet/repos/llvm/llvm/lib/Support/Signals.cpp:105:18
>    #2 0x000000000746e9ba SignalHandler(int) /usr/local/google/home/kadircet/repos/llvm/llvm/lib/Support/Unix/Signals.inc:413:1
>    #3 0x00007efd7465a540 (/lib/x86_64-linux-gnu/libc.so.6+0x3c540)
>    #4 0x00007efd746a812c __pthread_kill_implementation ./nptl/pthread_kill.c:44:76
>    #5 0x00007efd7465a4a2 raise ./signal/../sysdeps/posix/raise.c:27:6
>    #6 0x00007efd746444b2 abort ./stdlib/abort.c:81:7
>    #7 0x00007efd746443d5 _nl_load_domain ./intl/loadmsgcat.c:1177:9
>    #8 0x00007efd746533a2 (/lib/x86_64-linux-gnu/libc.so.6+0x353a2)
>    #9 0x000000000a014bf8 clang::LookupResult::checkDebugAssumptions() const /usr/local/google/home/kadircet/repos/llvm/clang/lib/Sema/SemaLookup.cpp:334:3
>   #10 0x0000000009b95356 getResultKind /usr/local/google/home/kadircet/repos/llvm/clang/include/clang/Sema/Lookup.h:342:5
>   #11 0x0000000009b95356 clang::Sema::ClassifyName(clang::Scope*, clang::CXXScopeSpec&, clang::IdentifierInfo*&, clang::SourceLocation, clang::Token const&, clang::CorrectionCandidateCallback*) /usr/local/google/home/kadircet/repos/llvm/clang/lib/Sema/SemaDecl.cpp:953:18
>   #12 0x00000000098a793e clang::Parser::TryAnnotateName(clang::CorrectionCandidateCallback*, clang::ImplicitTypenameContext) /usr/local/google/home/kadircet/repos/llvm/clang/lib/Parse/Parser.cpp:1770:53
>   #13 0x00000000099570dd clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::ParsedAttributes&, clang::ParsedAttributes&) /usr/local/google/home/kadircet/repos/llvm/clang/lib/Parse/ParseStmt.cpp:214:33
>   #14 0x0000000009956c55 clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*) /usr/local/google/home/kadircet/repos/llvm/clang/lib/Parse/ParseStmt.cpp:117:20
>   #15 0x0000000009960ab1 clang::Parser::ParseCompoundStatementBody(bool) /usr/local/google/home/kadircet/repos/llvm/clang/lib/Parse/ParseStmt.cpp:1205:11
>   #16 0x0000000009961a9d clang::Parser::ParseFunctionStatementBody(clang::Decl*, clang::Parser::ParseScope&) /usr/local/google/home/kadircet/repos/llvm/clang/lib/Parse/ParseStmt.cpp:2468:21
>   #17 0x0000000009954a3f isNot /usr/local/google/home/kadircet/repos/llvm/clang/include/clang/Lex/Token.h:99:52
>   #18 0x0000000009954a3f clang::Parser::ParseLexedMethodDef(clang::Parser::LexedMethod&) /usr/local/google/home/kadircet/repos/llvm/clang/lib/Parse/ParseCXXInlineMethods.cpp:600:14
>   #19 0x0000000009952e0a clang::Parser::ParseLexedMethodDefs(clang::Parser::ParsingClass&) /usr/local/google/home/kadircet/repos/llvm/clang/lib/Parse/ParseCXXInlineMethods.cpp:529:33
>   #20 0x00000000098f78e8 clang::Parser::ParseCXXMemberSpecification(clang::SourceLocation, clang::SourceLocation, clang::ParsedAttributes&, unsigned int, clang::Decl*) /usr/local/google/home/kadircet/repos/llvm/clang/lib/Parse/ParseDeclCXX.cpp:3674:21
>   #21 0x00000000098f4e9c clang::Parser::ParseClassSpecifier(clang::tok::TokenKind, clang::SourceLocation, clang::DeclSpec&, clang::Parser::ParsedTemplateInfo const&, clang::AccessSpecifier, bool, clang::Parser::DeclSpecContext, clang::ParsedAttributes&) /usr/local/google/home/kadircet/repos/llvm/clang/lib/Parse/ParseDeclCXX.cpp:0:7
>   #22 0x0000000009918955 empty /usr/local/google/home/kadircet/repos/llvm/llvm/include/llvm/ADT/SmallVector.h:94:46
>   #23 0x0000000009918955 empty /usr/local/google/home/kadircet/repos/llvm/clang/include/clang/Sema/ParsedAttr.h:819:40
>   #24 0x0000000009918955 clang::Parser::ParseDeclarationSpecifiers(clang::DeclSpec&, clang::Parser::ParsedTemplateInfo const&, clang::AccessSpecifier, clang::Parser::DeclSpecContext, clang::Parser::LateParsedAttrList*, clang::ImplicitTypenameContext) /usr/local/google/home/kadircet/repos/llvm/clang/lib/Parse/ParseDecl.cpp:4327:23
>   #25 0x00000000098a3234 clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) /usr/local/google/home/kadircet/repos/llvm/clang/lib/Parse/Parser.cpp:1123:10
>   #26 0x00000000098a2ed0 clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) /usr/local/google/home/kadircet/repos/llvm/clang/lib/Parse/Parser.cpp:1229:12
>   #27 0x00000000098a1e8e clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) /usr/local/google/home/kadircet/repos/llvm/clang/lib/Parse/Parser.cpp:0:14
>   #28 0x000000000989fad7 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) /usr/local/google/home/kadircet/repos/llvm/clang/lib/Parse/Parser.cpp:0:12
>   #29 0x000000000989f27f clang::Parser::ParseFirstTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) /usr/local/google/home/kadircet/repos/llvm/clang/lib/Parse/Parser.cpp:594:26
>   #30 0x0000000009899f6b clang::ParseAST(clang::Sema&, bool, bool) /usr/local/google/home/kadircet/repos/llvm/clang/lib/Parse/ParseAST.cpp:162:5
>   #31 0x0000000008037930 clang::FrontendAction::Execute() /usr/local/google/home/kadircet/repos/llvm/clang/lib/Frontend/FrontendAction.cpp:1067:10
>   #32 0x0000000007fab25f getPtr /usr/local/google/home/kadircet/repos/llvm/llvm/include/llvm/Support/Error.h:270:42
>   #33 0x0000000007fab25f operator bool /usr/local/google/home/kadircet/repos/llvm/llvm/include/llvm/Support/Error.h:233:16
>   #34 0x0000000007fab25f clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) /usr/local/google/home/kadircet/repos/llvm/clang/lib/Frontend/CompilerInstance.cpp:1054:23
>   #35 0x000000000811efff clang::ExecuteCompilerInvocation(clang::CompilerInstance*) /usr/local/google/home/kadircet/repos/llvm/clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp:272:25
>   #36 0x0000000004ee5ea8 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) /usr/local/google/home/kadircet/repos/llvm/clang/tools/driver/cc1_main.cpp:249:15
>   #37 0x0000000004ee2a41 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) /usr/local/google/home/kadircet/repos/llvm/clang/tools/driver/driver.cpp:0:12
>   #38 0x0000000004ee1c39 clang_main(int, char**, llvm::ToolContext const&) /usr/local/google/home/kadircet/repos/llvm/clang/tools/driver/driver.cpp:407:12
>   #39 0x0000000004ef2431 main /usr/local/google/home/kadircet/repos/llvm/build/tools/clang/tools/driver/clang-driver.cpp:15:3
>   #40 0x00007efd746456ca __libc_start_call_main ./csu/../sysdeps/nptl/libc_start_call_main.h:74:3
>   #41 0x00007efd74645785 call_init ./csu/../csu/libc-start.c:128:20
>   #42 0x00007efd74645785 __libc_start_main ./csu/../csu/libc-start.c:347:5
>   #43 0x0000000004ededa1 _start (/usr/local/google/home/kadircet/repos/llvm/build/bin/clang-17+0x4ededa1)
>
> (note that this assertion failure is leading into crashes in NDEBUG builds).
>
> Without this patch clang's output was:
>
>   $ ~/repos/llvm/build/bin/clang -xc++ repro.cc
>   repro.cc:2:10: error: unknown type name 'c'
>       2 |   static c a;
>         |          ^
>   repro.cc:2:12: error: member 'a' has the same name as its class
>       2 |   static c a;
>         |            ^
>   repro.cc:3:13: error: expected unqualified-id
>       3 |   void b(){a};
>         |             ^
>   3 errors generated
>
> Reverting for now as this is triggering lots of crashes in our production systems.

I'm not opposed to a revert if this is causing problems for your downstream, but be sure to also remove the changes from the 17.x branch if you go this route rather than fixing forward.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D154503/new/

https://reviews.llvm.org/D154503

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