[LLVMdev] Passing an array to an external function

[SArora]

Hi all,

I am new to LLVM, and I am learning how to use LLVM for profiling. I need to
pass an array to an external method, and insert a call instruction to the
method in the code.

After reading a few source files, I've tried using GetElementPtrInst to pass
an array, but it fails at llvm::GetElementPtrInst::hasAllZeroIndices() const
+ 0

			std::vector<Value*> Args(1);
                          	
                        //Vector with array values
                        SmallVector<Constant*, 2> counts;
                       
counts.push_back(ConstantInt::get(Type::getInt32Ty(BB->getContext()),32,
false));
                       
counts.push_back(ConstantInt::get(Type::getInt32Ty(BB->getContext()),12,
false));

			//Array with 2 integers
			ArrayType* ar_type =
llvm::ArrayType::get(llvm::Type::getInt32Ty(BI->getContext()),2);
                        Value* array = ConstantArray::get(&(*ar_type),
counts);
                            
                        //Indicies
  			std::vector<Value*> ids(1);
                       
ids.push_back(ConstantInt::get(Type::getInt32Ty(BB->getContext()),1));
                       
ids.push_back(ConstantInt::get(Type::getInt32Ty(BB->getContext()),2));
                            
                        Args[1] = GetElementPtrInst::Create(array, ids, "
");

                        //Instrument the branch target instructions
                        CallInst::Create(hook, Args,  "",CI);


Also, I 'hook' is defined as M.getOrInsertFunction("hook",
Type::getVoidTy(M.getContext()), 
                                                   
PointerType::get(Type::getInt32PtrTy(M.getContext()),0),  //??
                                                    (Type*)0); 

Could someone kindly keep me a few pointers on passing arrays to an external
function (say with the signature void hook(int abc[]) ). I am probably wrong
all the way through, and would really appreciate some help.


Thanks!




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