LLVM插入内部函数Cos [英] LLVM insert intrinsic function Cos

问题描述

我试图将内部的cos（）函数调用插入LLVM传递。我在FunctionPass中的代码：

  std :: vector< Type *> ARG_TYPE; 
 arg_type.push_back（Type :: getFloatTy（getGlobalContext（）））; 
函数* fun = Intrinsic :: getDeclaration（F.getParent（），Intrinsic :: cos，arg_type）; 
 CallInst * callInst = CallInst :: Create（fun，args，Twine（cos），（Instruction *）& I）; 
  

当我遗漏了最后一行产生的IR时：

  define i32 @main（）nounwind uwtable {
 entry：
 ... 
} 
 
 declare float @ llvm.cos.f32（float）nounwind readonly 
  

，但是包含CallInst我得到的是：

  0 opt 0x000000000094f4bf 
 1 opt 0x000000000094f9c9 
 2 libpthread.so.0 0x00007fb92b652cb0 
 3 opt 0x00000000008be244 llvm ::指令::指令（llvm :: Type *，unsigned int，llvm :: Use *，unsigned int，llvm :: Instruction *）+ 148 
 4 LLVMObfuscation.so 0x00007fb92a66c52f 
 5 LLVMObfuscation.so 0x00007fb92a66c9a5 
 6 LLVMObfuscation.so 0x00007fb92a66df21 
 7 opt 0x00000000008e921f llvm :: FPPassManager :: runOnFunction（llvm :: Function&）+ 591 
 8 opt 0x00000000008e9293 llvm :: FPPassManager :: runOnModule （llvm :: Module&）+ 51 
 9 opt 0x00000000008e8f34 llvm :: MPPassManager :: runOnModule（llvm :: Module& amp;）+ 532 
 10 opt 0x00000000008ea4fb llvm :: PassManagerImpl :: run（llvm :: Module& amp;）+ 171 
 11 opt 0x0000000000496208 main + 4104 
 12 libc.so.6 0x00007fb92a89376d __libc_start_main + 237 
 13 opt 0x000000000049cfe5 
  

我还需要做什么？我想我不需要在模块中定义这个功能。

发送给函数的参数是这样定义的：

  std： ：vector< Value *> ARGS; 
 args.push_back（fp）; 
  

先前插入了fp指令：

指令* fp = BinaryOperator :: Create（Instruction :: FSub，... 
  

变量I是inst_iterator，但我正在外部循环。

谢谢。

解决方案

我建议你使用 IRBuilder ，它简化了LLVM内部的IR生成过程。 ：

  std :: vector< Type *> arg_type; 
 arg_type.push_back（Type :: getFloatTy（getGlobalContext （））; 
函数* fun = Intrinsic :: getDeclaration（F.getParent（），Intrinsic :: cos，arg_type）; 
 IRBuilder> Builder（& I）; 
 Builder.CreateCall（fun，args）; 
  

I am trying to insert intrinsic cos() function call to LLVM pass. My code in a FunctionPass:

std::vector<Type *> arg_type;
arg_type.push_back(Type::getFloatTy(getGlobalContext()));
Function *fun = Intrinsic::getDeclaration(F.getParent(), Intrinsic::cos, arg_type);
CallInst* callInst = CallInst::Create(fun, args, Twine("cos"), (Instruction *)&I);

When I leave out last line generated IR is:

define i32 @main() nounwind uwtable {
entry:
...
}

declare float @llvm.cos.f32(float) nounwind readonly

, but with CallInst included all i get is:

0  opt                0x000000000094f4bf
1  opt                0x000000000094f9c9
2  libpthread.so.0    0x00007fb92b652cb0
3  opt                0x00000000008be244 llvm::Instruction::Instruction(llvm::Type*, unsigned int, llvm::Use*, unsigned int, llvm::Instruction*) + 148
4  LLVMObfuscation.so 0x00007fb92a66c52f
5  LLVMObfuscation.so 0x00007fb92a66c9a5
6  LLVMObfuscation.so 0x00007fb92a66df21
7  opt                0x00000000008e921f llvm::FPPassManager::runOnFunction(llvm::Function&) + 591
8  opt                0x00000000008e9293 llvm::FPPassManager::runOnModule(llvm::Module&) + 51
9  opt                0x00000000008e8f34 llvm::MPPassManager::runOnModule(llvm::Module&) + 532
10 opt                0x00000000008ea4fb llvm::PassManagerImpl::run(llvm::Module&) + 171
11 opt                0x0000000000496208 main + 4104
12 libc.so.6          0x00007fb92a89376d __libc_start_main + 237
13 opt                0x000000000049cfe5

What else do I need to do ? I think i do not need to define this function in module.

args sent to function is defined this way:

std::vector<Value *> args;
args.push_back(fp);

where fp is previously inserted Instruction:

Instruction *fp = BinaryOperator::Create(Instruction::FSub, ...

Variable I is inst_iterator, but i am doing this outside for cycle.

Thank you.

解决方案

I advice you to use IRBuilder. It simplifies IR generation inside LLVM pass. In your case you can use it like that:

std::vector<Type *> arg_type;
arg_type.push_back(Type::getFloatTy(getGlobalContext()));
Function *fun = Intrinsic::getDeclaration(F.getParent(), Intrinsic::cos, arg_type);
IRBuilder<> Builder(&I);
Builder.CreateCall(fun, args);

这篇关于LLVM插入内部函数Cos的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！