clang segfaults when file changes #12110
Description
| Bugzilla Link | 11738 |
| Version | trunk |
| OS | All |
| Reporter | LLVM Bugzilla Contributor |
| CC | @DougGregor |
Extended Description
The following bug is probably very stupid, and I don't mind if it gets closed, but I thought I would report it anyway.
Take any reasonable sized C++ file, call it X.cc (I preprocessed a boost file to get a ~2M file)
Execute the following command:
for i in `seq 10000`; do cat X.cc > t.cc; done &
While that is spinning in the background, type:
clang++ t.cc -c
A few times, and you are likely to see a crash like the one before. I am fairly sure this is not from clang++ just seeing a truncated file, as I have tried to truncate the file I was using in many places, and have not seen clang crash (I actually found this bug when my fuzzer started misbehaving and changing the file while clang was compiling. I get a segfault like the one below.
Note the files mentioned at the bottom, writen to /tmp, compile fine (well, often with errors, but no segfaults).
0 clang 0x0000000001b5f98f
1 clang 0x0000000001b5fe19
2 libpthread.so.0 0x00007f93be567060
3 clang 0x0000000000fbd1ac
4 clang 0x0000000000fc1af2 clang::SourceManager::getLineNumber(clang::FileID, unsigned int, bool*) const + 482
5 clang 0x0000000000fc2862 clang::SourceManager::getPresumedLoc(clang::SourceLocation) const + 450
6 clang 0x0000000000f78283 clang::Preprocessor::HandleDigitDirective(clang::Token&) + 2739
7 clang 0x0000000000f7dd33 clang::Preprocessor::HandleDirective(clang::Token&) + 1411
8 clang 0x0000000000f60128 clang::Lexer::LexTokenInternal(clang::Token&) + 2104
9 clang 0x0000000000f6181f clang::Lexer::LexTokenInternal(clang::Token&) + 7983
10 clang 0x0000000000882a38
11 clang 0x000000000087c73a clang::Parser::ExpectAndConsume(clang::tok::TokenKind, unsigned int, char const*, clang::tok::TokenKind) + 762
12 clang 0x00000000008905ee clang::Parser::ParseDeclGroup(clang::Parser::ParsingDeclSpec&, unsigned int, bool, clang::SourceLocation*, clang::Parser::ForRangeInit*) + 1886
13 clang 0x000000000089695c clang::Parser::ParseSimpleDeclaration(clang::ASTOwningVector<clang::Stmt*, 32u>&, unsigned int, clang::SourceLocation&, clang::ParsedAttributes&, bool, clang::Parser::ForRangeInit*) + 652
14 clang 0x0000000000896b02 clang::Parser::ParseDeclaration(clang::ASTOwningVector<clang::Stmt*, 32u>&, unsigned int, clang::SourceLocation&, clang::Parser::ParsedAttributesWithRange&) + 178
15 clang 0x000000000087eb4d clang::Parser::ParseExternalDeclaration(clang::Parser::ParsedAttributesWithRange&, clang::Parser::ParsingDeclSpec*) + 893
16 clang 0x000000000087f628 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&) + 168
17 clang 0x00000000008543cd clang::ParseAST(clang::Sema&, bool) + 269
18 clang 0x000000000060101d clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) + 317
19 clang 0x00000000005e7a1a clang::ExecuteCompilerInvocation(clang::CompilerInstance*) + 1114
20 clang 0x00000000005dc4b2 cc1_main(char const**, char const**, char const*, void*) + 866
21 clang 0x00000000005e62be main + 702
22 libc.so.6 0x00007f93bd83430d __libc_start_main + 237
23 clang 0x00000000005dbff9
Stack dump:
0. Program arguments: /scratch/dist/clang/bin/clang -cc1 -triple x86_64-unknown-linux-gnu -emit-obj -mrelax-all -disable-free -disable-llvm-verifier -main-file-name t.cc -mrelocation-model static -mdisable-fp-elim -masm-verbose -mconstructor-aliases -munwind-tables -target-cpu x86-64 -target-linker-version 2.21.53.20110810 -momit-leaf-frame-pointer -coverage-file t.o -resource-dir /scratch/dist/clang/bin/../lib/clang/3.1 -fmodule-cache-path /var/tmp/clang-module-cache -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/4.6/../../../../include/c++/4.6 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/4.6/../../../../include/c++/4.6/x86_64-linux-gnu -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/4.6/../../../../include/c++/4.6/backward -internal-isystem /usr/local/include -internal-isystem /scratch/dist/clang/bin/../lib/clang/3.1/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -fdeprecated-macro -fdebug-compilation-dir /home/caj/temp -ferror-limit 19 -fmessage-length 136 -mstackrealign -fgnu-runtime -fobjc-runtime-has-arc -fobjc-runtime-has-weak -fobjc-fragile-abi -fcxx-exceptions -fexceptions -fdiagnostics-show-option -fcolor-diagnostics -o t.o -x c++ t.cc
1. clang: error: unable to execute command: Bus error
clang: error: clang frontend command failed due to signal (use -v to see invocation)
clang: note: diagnostic msg: Please submit a bug report to http://llvm.org/bugs/ and include command line arguments and all diagnostic information.
clang: note: diagnostic msg: Preprocessed source(s) and associated run script(s) are located at:
clang: note: diagnostic msg: /tmp/t-VkNgCT.ii
clang: note: diagnostic msg: /tmp/t-VkNgCT.sh