basicAA crash on functions with empty names

[efriedma-quic]

Bugzilla Link	1801
Resolution	FIXED
Resolved on	Mar 06, 2010 14:00
Version	unspecified
OS	Windows XP
CC	@asl,@tlattner

Extended Description

declare void @""(i32, i32)
declare void @""(i32, i32)
define void @​EWEWEW(i32) {
call void @​0(i32 1, i32 2)
call void @​1(i32 1, i32 2)
ret void
}

Crashes when run through opt -std-compile-opts.

[asl]

Confirmed. valgrind is not clean:

==6461== Invalid read of size 4
==6461== at 0x85967E2: llvm::StringMapEntryBase::getKeyLength() const (StringMap.h:33)
==6461== by 0x8596324: (anonymous namespace)::BasicAliasAnalysis::getModRefBehavior(llvm::Function*, llvm::CallSite, std::vector<llvm::AliasAnalysis::PointerAccessInfo, std::allocatorllvm::AliasAnalysis::PointerAccessInfo >) (BasicAliasAnalysis.cpp:932)
==6461== by 0x846A746: llvm::AliasAnalysis::doesNotAccessMemory(llvm::Function) (AliasAnalysis.h:207)
==6461== by 0x846E2B1: (anonymous namespace)::ValueTable::lookup_or_add(llvm::Value*) (GVN.cpp:478)
==6461== by 0x8470285: (anonymous namespace)::GVN::processInstruction(llvm::Instruction*, (anonymous namespace)::ValueNumberedSet&, llvm::DenseMap<llvm::Value*, llvm::LoadInst*, llvm::DenseMapInfollvm::Value*, llvm::DenseMapInfollvm::LoadInst* >&, llvm::SmallVector<llvm::Instruction*, 4>&) (GVN.cpp:1022)
==6461== by 0x847069A: (anonymous namespace)::GVN::iterateOnFunction(llvm::Function&) (GVN.cpp:1100)
==6461== by 0x8470476: (anonymous namespace)::GVN::runOnFunction(llvm::Function&) (GVN.cpp:1063)
==6461== by 0x865F5D2: llvm::FPPassManager::runOnFunction(llvm::Function&) (PassManager.cpp:1171)
==6461== by 0x857F0A8: CGPassManager::runOnModule(llvm::Module&) (CallGraphSCCPass.cpp:111)
==6461== by 0x865F8C4: llvm::MPPassManager::runOnModule(llvm::Module&) (PassManager.cpp:1240)
==6461== by 0x865FC7D: llvm::PassManagerImpl::run(llvm::Module&) (PassManager.cpp:1313)
==6461== by 0x865FDE9: llvm::PassManager::run(llvm::Module&) (PassManager.cpp:1345)

[tlattner]

Would it be ok to just return UnknownModRefBehavior if it has no name?

ie..

if (!Name)
return UnknownModRefBehavior;

I can add that fix..

[lattner]

Yes, that is exactly the right fix, please commit.

[tlattner]

Fixed:
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20071112/055675.html