[LLVMdev] Module crash when adding CallInst

[Pankaj Kohli]

Thanks David. I will try using an asserts build.
I injected the call instruction before an instruction which has metadata.
This fixes the issue.

- Pankaj



On Wed, May 20, 2015 at 2:43 AM David Blaikie <dblaikie at gmail.com> wrote:

> Have you tried an asserts build of clang/llvm? If you're doing LLVM
> development you should probably be using an asserts build.
>
> I would guess you're hitting the issue where, if you have debug info for a
> function, any call instructions inside that function must themselves have a
> debug location (that !dbg thing). Otherwise bad debug info (and assertions
> to ensure that badness doesn't happen) happens.
>
> - David
>
> On Tue, May 19, 2015 at 1:15 AM, Pankaj Kohli <pankaj208 at gmail.com> wrote:
>
>> Hi,
>>
>> I am learning to write LLVM modules. I am using IRBuilder to insert calls
>> to an existing function. The call is to be inserted at a random location in
>> every function in the code. The call does get inserted, however, the module
>> crashes later (after doFinalization()). The crash happens only sometimes,
>> not always.
>>
>> These are the kind of instructions that I see in the generated code.
>>   %callins = call void @myfunc(), !dbg !285
>>   %callins = call void @myfunc()
>>
>> The stack trace shows the crash has something to do with debug
>> information. Do I need to add metadata or debug info to the newly added
>> call instruction? Any pointers on how I can do that?
>>
>> Here is the code snippet and the stack trace:
>>
>> IRBuilder<> Builder(ins); // to be inserted before ins
>> CallInst *call = Builder.CreateCall(func, "callins"); // call to func
>>
>>
>> 0  clang           0x0000000001492ec2
>> llvm::sys::PrintStackTrace(_IO_FILE*) + 34
>> 1  clang           0x0000000001490f61
>> 2  libpthread.so.0 0x00002b33bd0ee340
>> 3  clang           0x00000000016a43a6
>> llvm::DwarfUnit::addString(llvm::DIE&, llvm::dwarf::Attribute,
>> llvm::StringRef) + 22
>> 4  clang           0x00000000016c2003
>> llvm::DwarfCompileUnit::applyVariableAttributes(llvm::DbgVariable const&,
>> llvm::DIE&) + 915
>> 5  clang           0x000000000168bdfe
>> llvm::DwarfDebug::finishVariableDefinitions() + 270
>> 6  clang           0x0000000001690424
>> llvm::DwarfDebug::finalizeModuleInfo() + 52
>> 7  clang           0x000000000169c4a8 llvm::DwarfDebug::endModule() + 40
>> 8  clang           0x00000000016850f7
>> llvm::AsmPrinter::doFinalization(llvm::Module&) + 551
>> 9  clang           0x00000000011befe5
>> llvm::FPPassManager::doFinalization(llvm::Module&) + 69
>> 10 clang           0x00000000011ca40d
>> llvm::legacy::PassManagerImpl::run(llvm::Module&) + 813
>> 11 clang           0x0000000001837fad
>> clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::CodeGenOptions
>> const&, clang::TargetOptions const&, clang::LangOptions const&,
>> llvm::StringRef, llvm::Module*, clang::BackendAction, llvm::raw_ostream*) +
>> 1629
>> 12 clang           0x000000000182a47f
>> 13 clang           0x0000000001bdf043 clang::ParseAST(clang::Sema&, bool,
>> bool) + 483
>> 14 clang           0x0000000001603ba6 clang::FrontendAction::Execute() +
>> 118
>> 15 clang           0x00000000015e47b8
>> clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) + 280
>> 16 clang           0x0000000001673b41
>> clang::ExecuteCompilerInvocation(clang::CompilerInstance*) + 1921
>> 17 clang           0x0000000000820358 cc1_main(llvm::ArrayRef<char
>> const*>, char const*, void*) + 1320
>> 18 clang           0x00000000007fceaa main + 8298
>> 19 libc.so.6       0x00002b33bdd56ec5 __libc_start_main + 245
>> 20 clang           0x000000000081e5d9
>>
>> Any help is appreciated.
>>
>> Thanks,
>> Pankaj
>>
>>
>>
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>>
>
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