1 //===- ProfilingUtils.cpp - Helper functions shared by profilers ----------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This files implements a few helper functions which are used by profile
11 // instrumentation code to instrument the code. This allows the profiler pass
12 // to worry about *what* to insert, and these functions take care of *how* to do
15 //===----------------------------------------------------------------------===//
17 #include "ProfilingUtils.h"
18 #include "llvm/Constants.h"
19 #include "llvm/DerivedTypes.h"
20 #include "llvm/Instructions.h"
21 #include "llvm/Module.h"
23 void llvm::InsertProfilingInitCall(Function *MainFn, const char *FnName,
25 const Type *ArgVTy = PointerType::get(PointerType::get(Type::SByteTy));
26 const PointerType *UIntPtr = PointerType::get(Type::UIntTy);
27 Module &M = *MainFn->getParent();
28 Function *InitFn = M.getOrInsertFunction(FnName, Type::IntTy, Type::IntTy,
29 ArgVTy, UIntPtr, Type::UIntTy, 0);
31 // This could force argc and argv into programs that wouldn't otherwise have
32 // them, but instead we just pass null values in.
33 std::vector<Value*> Args(4);
34 Args[0] = Constant::getNullValue(Type::IntTy);
35 Args[1] = Constant::getNullValue(ArgVTy);
37 // Skip over any allocas in the entry block.
38 BasicBlock *Entry = MainFn->begin();
39 BasicBlock::iterator InsertPos = Entry->begin();
40 while (isa<AllocaInst>(InsertPos)) ++InsertPos;
42 std::vector<Constant*> GEPIndices(2, Constant::getNullValue(Type::IntTy));
43 unsigned NumElements = 0;
45 Args[2] = ConstantExpr::getGetElementPtr(Array, GEPIndices);
47 cast<ArrayType>(Array->getType()->getElementType())->getNumElements();
49 // If this profiling instrumentation doesn't have a constant array, just
51 Args[2] = ConstantPointerNull::get(UIntPtr);
53 Args[3] = ConstantUInt::get(Type::UIntTy, NumElements);
55 Instruction *InitCall = new CallInst(InitFn, Args, "newargc", InsertPos);
57 // If argc or argv are not available in main, just pass null values in.
58 Function::arg_iterator AI;
59 switch (MainFn->arg_size()) {
62 AI = MainFn->arg_begin(); ++AI;
63 if (AI->getType() != ArgVTy) {
64 InitCall->setOperand(2, new CastInst(AI, ArgVTy, "argv.cast", InitCall));
66 InitCall->setOperand(2, AI);
70 AI = MainFn->arg_begin();
71 // If the program looked at argc, have it look at the return value of the
73 if (AI->getType() != Type::IntTy) {
75 AI->replaceAllUsesWith(new CastInst(InitCall, AI->getType(), "",
77 InitCall->setOperand(1, new CastInst(AI, Type::IntTy, "argc.cast",
80 AI->replaceAllUsesWith(InitCall);
81 InitCall->setOperand(1, AI);
88 void llvm::IncrementCounterInBlock(BasicBlock *BB, unsigned CounterNum,
89 GlobalValue *CounterArray) {
90 // Insert the increment after any alloca or PHI instructions...
91 BasicBlock::iterator InsertPos = BB->begin();
92 while (isa<AllocaInst>(InsertPos) || isa<PHINode>(InsertPos))
95 // Create the getelementptr constant expression
96 std::vector<Constant*> Indices(2);
97 Indices[0] = Constant::getNullValue(Type::IntTy);
98 Indices[1] = ConstantSInt::get(Type::IntTy, CounterNum);
99 Constant *ElementPtr = ConstantExpr::getGetElementPtr(CounterArray, Indices);
101 // Load, increment and store the value back.
102 Value *OldVal = new LoadInst(ElementPtr, "OldFuncCounter", InsertPos);
103 Value *NewVal = BinaryOperator::create(Instruction::Add, OldVal,
104 ConstantInt::get(Type::UIntTy, 1),
105 "NewFuncCounter", InsertPos);
106 new StoreInst(NewVal, ElementPtr, InsertPos);