[cfe-dev] Threading and Clang

Tue Sep 14 04:22:52 PDT 2010

Hi Chris,

I checked out the lastest LLVM and Clang from trunk last night.  It
still crashes, here's the backtrace.  Any other ideas?  Is the way we're
using it supposed to work?  If it is, we can dig in and see what's going
wrong.

Bes,

Martin

*** glibc detected *** ./boom: double free or corruption (fasttop):
0x0000000004136370 ***

======= Backtrace: =========

/lib/libc.so.6[0x7fc2fe7a92f6]

/lib/libc.so.6(cfree+0x6c)[0x7fc2fe7adc6c]

./boom(__gnu_cxx::new_allocator<llvm::PassRegistrationListener*>::deallo
cate(llvm::PassRegistrationListener**, unsigned long)+0x1d)[0x1c24c85]

./boom(std::_Vector_base<llvm::PassRegistrationListener*,
std::allocator<llvm::PassRegistrationListener*>
>::_M_deallocate(llvm::PassRegistrationListener**, unsigned
long)+0x2f)[0x1c24cb7]

./boom(std::vector<llvm::PassRegistrationListener*,
std::allocator<llvm::PassRegistrationListener*>
>::_M_insert_aux(__gnu_cxx::__normal_iterator<llvm::PassRegistrationList
ener**, std::vector<llvm::PassRegistrationListener*,
std::allocator<llvm::PassRegistrationListener*> > >,
llvm::PassRegistrationListener* const&)+0x310)[0x1c24fca]

./boom(std::vector<llvm::PassRegistrationListener*,
std::allocator<llvm::PassRegistrationListener*>
>::push_back(llvm::PassRegistrationListener* const&)+0x6c)[0x1c25098]

./boom(llvm::PassRegistry::addRegistrationListener(llvm::PassRegistratio
nListener*)+0x2e)[0x1c22f90]

./boom(llvm::PassRegistrationListener::PassRegistrationListener()+0x2f)[
0x1c12163]

./boom((anonymous
namespace)::GetCFGOnlyPasses::GetCFGOnlyPasses(llvm::SmallVector<void
const*, 32u>&)+0x19)[0x1c132b5]

./boom(llvm::AnalysisUsage::setPreservesCFG()+0x20)[0x1c12186]

./boom((anonymous
namespace)::SROA::getAnalysisUsage(llvm::AnalysisUsage&)
const+0x2b)[0x1a0b78d]

./boom(llvm::PMTopLevelManager::findAnalysisUsage(llvm::Pass*)+0xa7)[0x1
c14917]

./boom(llvm::PMTopLevelManager::schedulePass(llvm::Pass*)+0xd7)[0x1c15e3
b]

./boom(llvm::FunctionPassManagerImpl::add(llvm::Pass*)+0x24)[0x1c22398]

./boom(llvm::FunctionPassManager::addImpl(llvm::Pass*)+0x21)[0x1c1638d]

./boom(llvm::FunctionPassManager::add(llvm::Pass*)+0x12c)[0x1c164bc]

./boom[0x107e70b]

./boom((anonymous
namespace)::EmitAssemblyHelper::CreatePasses()+0xaf)[0x107ed0f]

./boom((anonymous
namespace)::EmitAssemblyHelper::EmitAssembly(clang::BackendAction,
llvm::raw_ostream*)+0x77)[0x107ee83]

./boom(clang::EmitBackendOutput(clang::Diagnostic&,
clang::CodeGenOptions const&, clang::TargetOptions const&,
llvm::Module*, clang::BackendAction,
llvm::raw_ostream*)+0x73)[0x107f255]

./boom((anonymous
namespace)::BackendConsumer::HandleTranslationUnit(clang::ASTContext&)+0
x189)[0x107ce91]

./boom(clang::ParseAST(clang::Sema&, bool)+0x216)[0x11bc388]

./boom(clang::ASTFrontendAction::ExecuteAction()+0xea)[0xf4e370]

./boom(clang::CodeGenAction::ExecuteAction()+0x352)[0x107b87c]

./boom(clang::FrontendAction::Execute()+0x100)[0xf4e478]

./boom(clang::CompilerInstance::ExecuteAction(clang::FrontendAction&)+0x
294)[0xf35414]

./boom(go(void*)+0x25f)[0xf2ff93]

/lib/libpthread.so.0[0x7fc2ff458a04]

/lib/libc.so.6(clone+0x6d)[0x7fc2fe812d4d]

From: Chris Lattner [mailto:clattner at apple.com] 
Sent: Monday, September 13, 2010 6:43 PM
To: Martin C. Martin
Cc: Clang Dev; Owen Anderson
Subject: Re: [cfe-dev] Threading and Clang

On Sep 13, 2010, at 2:20 PM, Martin C. Martin wrote:

Hi,

We're considering using Clang as a just in time compiler.  It works
great in a single thread, but we can't get it working from multiple
threads.

Here's one attempt, where we create a single execution engine used by
all threads, and one compiler instance per thread.  The result is
corruption and a core dump.  We've also tried giving each thread its own
execution engine, still no dice.  This is with Clang/LLVM 2.7 on Ubuntu
9.10.

I'm not sure, but I'd strongly recommend upgrading to llvm 2.8
prerelease.

-Chris

I've also attached a self contained zip file with the exact compile line
and code that reproduces the problem.

Any idea what we're doing wrong?

Thanks,

Martin

Here's an example stack trace:

*** glibc detected *** ./boom: double free or corruption (fasttop):
0x00007fb9b421c9b0 ***

======= Backtrace: =========

/lib/libc.so.6[0x7fbabcf352f6]

/lib/libc.so.6(cfree+0x6c)[0x7fbabcf39c6c]

./boom(llvm::AttributeListImpl::DropRef()+0x3e)[0x18b4a4c]

./boom(llvm::AttrListPtr::operator=(llvm::AttrListPtr
const&)+0x45)[0x18b3953]

./boom(llvm::Function::setAttributes(llvm::AttrListPtr
const&)+0x24)[0xec2e1c]

./boom(llvm::Function::addAttribute(unsigned int, unsigned
int)+0x5d)[0x19101e5]

./boom(llvm::Argument::addAttr(unsigned int)+0x32)[0x191094a]

./boom((anonymous
namespace)::FunctionAttrs::AddNoCaptureAttrs(std::vector<llvm::CallGraph
Node*, std::allocator<llvm::CallGraphNode*> > const&)+0x131)[0x12e3f05]

./boom((anonymous
namespace)::FunctionAttrs::runOnSCC(std::vector<llvm::CallGraphNode*,
std::allocator<llvm::CallGraphNode*> >&)+0x32)[0x12e464e]

./boom((anonymous namespace)::CGPassManager::RunPassOnSCC(llvm::Pass*,
std::vector<llvm::CallGraphNode*, std::allocator<llvm::CallGraphNode*>
>&, llvm::CallGraph&, bool&)+0xa8)[0x17fafb4]

./boom((anonymous
namespace)::CGPassManager::runOnModule(llvm::Module&)+0x24e)[0x17fb418]

./boom(llvm::MPPassManager::runOnModule(llvm::Module&)+0x17e)[0x194930c]

./boom(llvm::PassManagerImpl::run(llvm::Module&)+0x6f)[0x194b0b1]

./boom(llvm::PassManager::run(llvm::Module&)+0x21)[0x194b113]

./boom((anonymous
namespace)::BackendConsumer::EmitAssembly()+0x241)[0xdfc3f9]

./boom((anonymous
namespace)::BackendConsumer::HandleTranslationUnit(clang::ASTContext&)+0
x91)[0xdffcef]

./boom(clang::ParseAST(clang::Preprocessor&, clang::ASTConsumer*,
clang::ASTContext&, bool, bool,
clang::CodeCompleteConsumer*)+0x2a4)[0xfc7164]

./boom(clang::ASTFrontendAction::ExecuteAction()+0x100)[0xe177a2]

./boom(clang::FrontendAction::Execute()+0xe2)[0xe17892]

./boom(clang::CompilerInstance::ExecuteAction(clang::FrontendAction&)+0x
2a3)[0xe01427]

./boom(go(void*)+0x25f)[0xdf64f3]

/lib/libpthread.so.0[0x7fbabd9e0a04]

/lib/libc.so.6(clone+0x6d)[0x7fbabcf9ed4d]

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