llvm dev - Feb 2012 - [LLVMdev] Function Insertion Error

Hi,
I am trying to insert a function into the LLVM IR. But i get a stack dump
exception. My code is as follows.

 

#include "llvm/Pass.h" 
#include "llvm/Function.h" 
#include "llvm/Module.h" 
#include "llvm/Support/raw_ostream.h" 
#include "llvm/ADT/Statistic.h" 
#include "llvm/Support/IRBuilder.h" 
using namespace llvm; 
 

namespace { 
  struct FunctionInsert : public ModulePass { 
    static char ID;
    FunctionInsert() : ModulePass(ID) {} 

  }; 
    virtual bool runOnModule(Module &M) { 
     

     FunctionType* ty=FunctionType::get(Type::getInt32Ty(M.getContext()),false);

       Function *func = 
cast<Function>(M.getOrInsertFunction("func",
ty,Type::getInt32Ty(M.getContext()),  (Type *)0)); 
      BasicBlock *BB = BasicBlock::Create(M.getContext(), "bb1",
func);
      IRBuilder<> builder(BB); 
       Value *One = builder.getInt32(1); 
      Argument *ArgX = func->arg_begin();    
      ArgX->setName("firstarg");             
     Value *Add = builder.CreateAdd(One, ArgX); 
     builder.CreateRet(Add); 
    return true; 
    } 
  }; 
} 
 
char FunctionInsert::ID = 0; 
static RegisterPass<FunctionInsert> X("FunctionInsert",
"Function Insertion Pass");

Most of the above code is from the file examples/HowToUseJIT/HowToUseJIT.cpp.
Thanks
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Hi Rohit,
> I am trying to insert a function into the LLVM IR. But i get a stack dump
> exception.
you should include the message since it can help us understand what you did
wrong.  You built LLVM with assertions enabled, right?

  My code is as follows.
>
>
>
> #include "llvm/Pass.h"
> #include "llvm/Function.h"
> #include "llvm/Module.h"
> #include "llvm/Support/raw_ostream.h"
> #include "llvm/ADT/Statistic.h"
> #include "llvm/Support/IRBuilder.h"
> using namespace llvm;
>
>
> namespace {
> struct FunctionInsert : public ModulePass {
> static char ID;
> FunctionInsert() : ModulePass(ID) {}
>
> };
> virtual bool runOnModule(Module &M) {
>
>
> FunctionType* ty=FunctionType::get(Type::getInt32Ty(M.getContext()),false);
A function with no parameters that returns an int: int func(void)
However I think you wanted a function that also has an int argument, thus
this should have been

   FunctionType* ty=FunctionType::get(Type::getInt32Ty(M.getContext()),
     Type::getInt32Ty(M.getContext()), false);

which corresponds to: int func(int)
> Function *func =
cast<Function>(M.getOrInsertFunction("func",
> ty,Type::getInt32Ty(M.getContext()), (Type *)0));
Inserting a function that returns type ty and has one argument of type int.
Clearly you don't mean to have your function return a value of function type
(which is what ty is).  Probably you meant:

   Function *func = cast<Function>(M.getOrInsertFunction("func",
ty));

This will insert a function with type ty, i.e. int func(int)

I didn't look at the rest since this first part needs to be sorted out
before worrying about anything else.

Ciao, Duncan.
> BasicBlock *BB = BasicBlock::Create(M.getContext(), "bb1", func);
> IRBuilder<> builder(BB);
> Value *One = builder.getInt32(1);
> Argument *ArgX = func->arg_begin();
> ArgX->setName("firstarg");
> Value *Add = builder.CreateAdd(One, ArgX);
> builder.CreateRet(Add);
> return true;
> }
> };
> }
>
> char FunctionInsert::ID = 0;
> static RegisterPass<FunctionInsert> X("FunctionInsert",
"Function Insertion Pass");
>
> Most of the above code is from the file
examples/HowToUseJIT/HowToUseJIT.cpp.
> Thanks:) happy
>
>
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