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//===- ProfilingUtils.cpp - Helper functions shared by profilers ----------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements a few helper functions which are used by profile
// instrumentation code to instrument the code. This allows the profiler pass
// to worry about *what* to insert, and these functions take care of *how* to do
// it.
//
//===----------------------------------------------------------------------===//
#include "ProfilingUtils.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Instructions.h"
#include "llvm/LLVMContext.h"
#include "llvm/Module.h"
void llvm::InsertProfilingInitCall(Function *MainFn, const char *FnName,
GlobalValue *Array,
PointerType *arrayType) {
LLVMContext &Context = MainFn->getContext();
Type *ArgVTy =
PointerType::getUnqual(Type::getInt8PtrTy(Context));
PointerType *UIntPtr = arrayType ? arrayType :
Type::getInt32PtrTy(Context);
Module &M = *MainFn->getParent();
Constant *InitFn = M.getOrInsertFunction(FnName, Type::getInt32Ty(Context),
Type::getInt32Ty(Context),
ArgVTy, UIntPtr,
Type::getInt32Ty(Context),
(Type *)0);
// This could force argc and argv into programs that wouldn't otherwise have
// them, but instead we just pass null values in.
std::vector<Value*> Args(4);
Args[0] = Constant::getNullValue(Type::getInt32Ty(Context));
Args[1] = Constant::getNullValue(ArgVTy);
// Skip over any allocas in the entry block.
BasicBlock *Entry = MainFn->begin();
BasicBlock::iterator InsertPos = Entry->begin();
while (isa<AllocaInst>(InsertPos)) ++InsertPos;
std::vector<Constant*> GEPIndices(2,
Constant::getNullValue(Type::getInt32Ty(Context)));
unsigned NumElements = 0;
if (Array) {
Args[2] = ConstantExpr::getGetElementPtr(Array, GEPIndices);
NumElements =
cast<ArrayType>(Array->getType()->getElementType())->getNumElements();
} else {
// If this profiling instrumentation doesn't have a constant array, just
// pass null.
Args[2] = ConstantPointerNull::get(UIntPtr);
}
Args[3] = ConstantInt::get(Type::getInt32Ty(Context), NumElements);
CallInst *InitCall = CallInst::Create(InitFn, Args, "newargc", InsertPos);
// If argc or argv are not available in main, just pass null values in.
Function::arg_iterator AI;
switch (MainFn->arg_size()) {
default:
case 2:
AI = MainFn->arg_begin(); ++AI;
if (AI->getType() != ArgVTy) {
Instruction::CastOps opcode = CastInst::getCastOpcode(AI, false, ArgVTy,
false);
InitCall->setArgOperand(1,
CastInst::Create(opcode, AI, ArgVTy, "argv.cast", InitCall));
} else {
InitCall->setArgOperand(1, AI);
}
/* FALL THROUGH */
case 1:
AI = MainFn->arg_begin();
// If the program looked at argc, have it look at the return value of the
// init call instead.
if (!AI->getType()->isIntegerTy(32)) {
Instruction::CastOps opcode;
if (!AI->use_empty()) {
opcode = CastInst::getCastOpcode(InitCall, true, AI->getType(), true);
AI->replaceAllUsesWith(
CastInst::Create(opcode, InitCall, AI->getType(), "", InsertPos));
}
opcode = CastInst::getCastOpcode(AI, true,
Type::getInt32Ty(Context), true);
InitCall->setArgOperand(0,
CastInst::Create(opcode, AI, Type::getInt32Ty(Context),
"argc.cast", InitCall));
} else {
AI->replaceAllUsesWith(InitCall);
InitCall->setArgOperand(0, AI);
}
case 0: break;
}
}
void llvm::IncrementCounterInBlock(BasicBlock *BB, unsigned CounterNum,
GlobalValue *CounterArray, bool beginning) {
// Insert the increment after any alloca or PHI instructions...
BasicBlock::iterator InsertPos = beginning ? BB->getFirstInsertionPt() :
BB->getTerminator();
while (isa<AllocaInst>(InsertPos))
++InsertPos;
LLVMContext &Context = BB->getContext();
// Create the getelementptr constant expression
std::vector<Constant*> Indices(2);
Indices[0] = Constant::getNullValue(Type::getInt32Ty(Context));
Indices[1] = ConstantInt::get(Type::getInt32Ty(Context), CounterNum);
Constant *ElementPtr =
ConstantExpr::getGetElementPtr(CounterArray, Indices);
// Load, increment and store the value back.
Value *OldVal = new LoadInst(ElementPtr, "OldFuncCounter", InsertPos);
Value *NewVal = BinaryOperator::Create(Instruction::Add, OldVal,
ConstantInt::get(Type::getInt32Ty(Context), 1),
"NewFuncCounter", InsertPos);
new StoreInst(NewVal, ElementPtr, InsertPos);
}
void llvm::InsertProfilingShutdownCall(Function *Callee, Module *Mod) {
// llvm.global_dtors is an array of type { i32, void ()* }. Prepare those
// types.
Type *GlobalDtorElems[2] = {
Type::getInt32Ty(Mod->getContext()),
FunctionType::get(Type::getVoidTy(Mod->getContext()), false)->getPointerTo()
};
StructType *GlobalDtorElemTy =
StructType::get(Mod->getContext(), GlobalDtorElems, false);
// Construct the new element we'll be adding.
Constant *Elem[2] = {
ConstantInt::get(Type::getInt32Ty(Mod->getContext()), 65535),
ConstantExpr::getBitCast(Callee, GlobalDtorElems[1])
};
// If llvm.global_dtors exists, make a copy of the things in its list and
// delete it, to replace it with one that has a larger array type.
std::vector<Constant *> dtors;
if (GlobalVariable *GlobalDtors = Mod->getNamedGlobal("llvm.global_dtors")) {
if (ConstantArray *InitList =
dyn_cast<ConstantArray>(GlobalDtors->getInitializer())) {
for (unsigned i = 0, e = InitList->getType()->getNumElements();
i != e; ++i)
dtors.push_back(cast<Constant>(InitList->getOperand(i)));
}
GlobalDtors->eraseFromParent();
}
// Build up llvm.global_dtors with our new item in it.
GlobalVariable *GlobalDtors = new GlobalVariable(
*Mod, ArrayType::get(GlobalDtorElemTy, 1), false,
GlobalValue::AppendingLinkage, NULL, "llvm.global_dtors");
dtors.push_back(ConstantStruct::get(GlobalDtorElemTy, Elem));
GlobalDtors->setInitializer(ConstantArray::get(
cast<ArrayType>(GlobalDtors->getType()->getElementType()), dtors));
}
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