[llvm-dev] How to use llvm.addressofreturnaddress() function？

[Eli Friedman via llvm-dev]

Two issues:


  1.  You usually want to use Module:: getOrInsertFunction to construct a function declaration, so you get the existing declaration if it already exists. This should avoid the “.1” suffix.
  2.  If you’re using Intrinsic::getDeclaration to get an intrinsic declaration, you have to pass the overloaded type (an i8*) as the third argument to the function.

-Eli

From: llvm-dev <llvm-dev-bounces at lists.llvm.org> On Behalf Of y liu via llvm-dev
Sent: Monday, April 6, 2020 12:08 AM
To: llvm-dev at lists.llvm.org
Subject: [EXT] [llvm-dev] How to use llvm.addressofreturnaddress() function？

Hi, I want to check the return address of function.
I use the following code to build pass.
"
    FunctionType *func_type = FunctionType::get(ty_ptr, false);
    Function *func = Function::Create(func_type, GlobalValue::ExternalLinkage, "llvm.addressofreturnaddress", F->getParent());
    IRBuilder<> Builder(inst);
    Builder.CreateCall(func);
"
When I compiled it, the following error message appeared:
"
   Intrinsic name not mangled correctly for type arguments! Should be: llvm.addressofreturnaddress.p0i8
   i8* ()* @llvm.addressofreturnaddress
"
So I made the following modification:
"
    FunctionType *func_type = FunctionType::get(ty_ptr, false);
    Function *func = Function::Create(func_type, GlobalValue::ExternalLinkage, "llvm.addressofreturnaddress.p0i8", F->getParent());
    IRBuilder<> Builder(inst);
    Builder.CreateCall(func);
"
Compile through, I get the compiled so file.
However, the following error occurred when I used it to optimize my code:
"
    Intrinsic name not mangled correctly for type arguments! Should be: llvm.addressofreturnaddress.p0i8
    i8* ()* @llvm.addressofreturnaddress.p0i8.1 in function main
"
I can't fix it. What should I do?

Then, I tried another way.
"
 CallInst *IRBuilderBase::CreateIntrinsic(Intrinsic::ID ID,
751  ArrayRef<Type *> Types,
752  ArrayRef<Value *> Args,
753  Instruction *FMFSource,
754  const Twine &Name) {
755  Module *M = BB->getModule();
756  Function *Fn = Intrinsic::getDeclaration(M, ID, Types);
757  return createCallHelper(Fn, Args, this, Name, FMFSource);
758 }
"
I use the following code.
"
    Function *Fn = Intrinsic::getDeclaration(F->getParent(), Intrinsic::addressofreturnaddress);
"
But,
"
Stack dump:
0. Program arguments: opt -load ../build/lib/LLVMMyPass.so -hello
1. Running pass 'Function Pass Manager' on module '<stdin>'.
2. Running pass 'Hello World Pass' on function '@_Z4vulnv'
 #0 0x0000563d2d976bba llvm::sys::PrintStackTrace(llvm::raw_ostream&) (/opt/llvm/bin/opt+0x2458bba)
 #1 0x0000563d2d974954 llvm::sys::RunSignalHandlers() (/opt/llvm/bin/opt+0x2456954)
 #2 0x0000563d2d974a92 SignalHandler(int) (/opt/llvm/bin/opt+0x2456a92)
 #3 0x00007fce4a662890 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x12890)
 #4 0x0000563d2d238bd4 DecodeFixedType(llvm::ArrayRef<llvm::Intrinsic::IITDescriptor>&, llvm::ArrayRef<llvm::Type*>, llvm::LLVMContext&) (/opt/llvm/bin/opt+0x1d1abd4)
 #5 0x0000563d2d23b576 llvm::Intrinsic::getType(llvm::LLVMContext&, llvm::Intrinsic::ID, llvm::ArrayRef<llvm::Type*>) (/opt/llvm/bin/opt+0x1d1d576)
 #6 0x0000563d2d240ab5 llvm::Intrinsic::getDeclaration(llvm::Module*, llvm::Intrinsic::ID, llvm::ArrayRef<llvm::Type*>) (/opt/llvm/bin/opt+0x1d22ab5)
 #7 0x00007fce492f095a (anonymous namespace)::Hello::runOnFunction(llvm::Function&) (../build/lib/LLVMMyPass.so+0x195a)
 #8 0x0000563d2d27db08 llvm::FPPassManager::runOnFunction(llvm::Function&) (/opt/llvm/bin/opt+0x1d5fb08)
 #9 0x0000563d2d27e1f1 llvm::FPPassManager::runOnModule(llvm::Module&) (/opt/llvm/bin/opt+0x1d601f1)
#10 0x0000563d2d27ce61 llvm::legacy::PassManagerImpl::run(llvm::Module&) (/opt/llvm/bin/opt+0x1d5ee61)
#11 0x0000563d2bc5c193 main (/opt/llvm/bin/opt+0x73e193)
#12 0x00007fce49513b97 __libc_start_main /build/glibc-OTsEL5/glibc-2.27/csu/../csu/libc-start.c:344:0
#13 0x0000563d2bce06ba _start (/opt/llvm/bin/opt+0x7c26ba)
Segmentation fault (core dumped)
"
I can't understand it.
I tried to use "returnaddress" to replace "addressofreturnaddress". It's OK!
They are all Intrinsic function. Why?

Plese help me out.
Thanks.
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