Disable stack coloring with register for now. It's not able to set kill markers.
[llvm/avr.git] / lib / Transforms / Utils / LowerAllocations.cpp
blobce7b04a4978e630ff37ad03b9f2317397b89cd97
1 //===- LowerAllocations.cpp - Reduce malloc & free insts to calls ---------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // The LowerAllocations transformation is a target-dependent tranformation
11 // because it depends on the size of data types and alignment constraints.
13 //===----------------------------------------------------------------------===//
15 #define DEBUG_TYPE "lowerallocs"
16 #include "llvm/Transforms/Scalar.h"
17 #include "llvm/Transforms/Utils/UnifyFunctionExitNodes.h"
18 #include "llvm/Module.h"
19 #include "llvm/DerivedTypes.h"
20 #include "llvm/Instructions.h"
21 #include "llvm/Constants.h"
22 #include "llvm/LLVMContext.h"
23 #include "llvm/Pass.h"
24 #include "llvm/ADT/Statistic.h"
25 #include "llvm/Target/TargetData.h"
26 #include "llvm/Support/Compiler.h"
27 using namespace llvm;
29 STATISTIC(NumLowered, "Number of allocations lowered");
31 namespace {
32 /// LowerAllocations - Turn malloc and free instructions into %malloc and
33 /// %free calls.
34 ///
35 class VISIBILITY_HIDDEN LowerAllocations : public BasicBlockPass {
36 Constant *MallocFunc; // Functions in the module we are processing
37 Constant *FreeFunc; // Initialized by doInitialization
38 bool LowerMallocArgToInteger;
39 public:
40 static char ID; // Pass ID, replacement for typeid
41 explicit LowerAllocations(bool LowerToInt = false)
42 : BasicBlockPass(&ID), MallocFunc(0), FreeFunc(0),
43 LowerMallocArgToInteger(LowerToInt) {}
45 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
46 AU.addRequired<TargetData>();
47 AU.setPreservesCFG();
49 // This is a cluster of orthogonal Transforms:
50 AU.addPreserved<UnifyFunctionExitNodes>();
51 AU.addPreservedID(PromoteMemoryToRegisterID);
52 AU.addPreservedID(LowerSwitchID);
53 AU.addPreservedID(LowerInvokePassID);
56 /// doPassInitialization - For the lower allocations pass, this ensures that
57 /// a module contains a declaration for a malloc and a free function.
58 ///
59 bool doInitialization(Module &M);
61 virtual bool doInitialization(Function &F) {
62 return doInitialization(*F.getParent());
65 /// runOnBasicBlock - This method does the actual work of converting
66 /// instructions over, assuming that the pass has already been initialized.
67 ///
68 bool runOnBasicBlock(BasicBlock &BB);
72 char LowerAllocations::ID = 0;
73 static RegisterPass<LowerAllocations>
74 X("lowerallocs", "Lower allocations from instructions to calls");
76 // Publically exposed interface to pass...
77 const PassInfo *const llvm::LowerAllocationsID = &X;
78 // createLowerAllocationsPass - Interface to this file...
79 Pass *llvm::createLowerAllocationsPass(bool LowerMallocArgToInteger) {
80 return new LowerAllocations(LowerMallocArgToInteger);
84 // doInitialization - For the lower allocations pass, this ensures that a
85 // module contains a declaration for a malloc and a free function.
87 // This function is always successful.
89 bool LowerAllocations::doInitialization(Module &M) {
90 const Type *BPTy = PointerType::getUnqual(Type::Int8Ty);
91 // Prototype malloc as "char* malloc(...)", because we don't know in
92 // doInitialization whether size_t is int or long.
93 FunctionType *FT = FunctionType::get(BPTy, true);
94 MallocFunc = M.getOrInsertFunction("malloc", FT);
95 FreeFunc = M.getOrInsertFunction("free" , Type::VoidTy, BPTy, (Type *)0);
96 return true;
99 // runOnBasicBlock - This method does the actual work of converting
100 // instructions over, assuming that the pass has already been initialized.
102 bool LowerAllocations::runOnBasicBlock(BasicBlock &BB) {
103 bool Changed = false;
104 assert(MallocFunc && FreeFunc && "Pass not initialized!");
106 BasicBlock::InstListType &BBIL = BB.getInstList();
108 const TargetData &TD = getAnalysis<TargetData>();
109 const Type *IntPtrTy = TD.getIntPtrType();
111 // Loop over all of the instructions, looking for malloc or free instructions
112 for (BasicBlock::iterator I = BB.begin(), E = BB.end(); I != E; ++I) {
113 if (MallocInst *MI = dyn_cast<MallocInst>(I)) {
114 const Type *AllocTy = MI->getType()->getElementType();
116 // malloc(type) becomes i8 *malloc(size)
117 Value *MallocArg;
118 if (LowerMallocArgToInteger)
119 MallocArg = ConstantInt::get(Type::Int64Ty,
120 TD.getTypeAllocSize(AllocTy));
121 else
122 MallocArg = ConstantExpr::getSizeOf(AllocTy);
123 MallocArg =
124 ConstantExpr::getTruncOrBitCast(cast<Constant>(MallocArg),
125 IntPtrTy);
127 if (MI->isArrayAllocation()) {
128 if (isa<ConstantInt>(MallocArg) &&
129 cast<ConstantInt>(MallocArg)->isOne()) {
130 MallocArg = MI->getOperand(0); // Operand * 1 = Operand
131 } else if (Constant *CO = dyn_cast<Constant>(MI->getOperand(0))) {
132 CO =
133 ConstantExpr::getIntegerCast(CO, IntPtrTy, false /*ZExt*/);
134 MallocArg = ConstantExpr::getMul(CO,
135 cast<Constant>(MallocArg));
136 } else {
137 Value *Scale = MI->getOperand(0);
138 if (Scale->getType() != IntPtrTy)
139 Scale = CastInst::CreateIntegerCast(Scale, IntPtrTy, false /*ZExt*/,
140 "", I);
142 // Multiply it by the array size if necessary...
143 MallocArg = BinaryOperator::Create(Instruction::Mul, Scale,
144 MallocArg, "", I);
148 // Create the call to Malloc.
149 CallInst *MCall = CallInst::Create(MallocFunc, MallocArg, "", I);
150 MCall->setTailCall();
152 // Create a cast instruction to convert to the right type...
153 Value *MCast;
154 if (MCall->getType() != Type::VoidTy)
155 MCast = new BitCastInst(MCall, MI->getType(), "", I);
156 else
157 MCast = Constant::getNullValue(MI->getType());
159 // Replace all uses of the old malloc inst with the cast inst
160 MI->replaceAllUsesWith(MCast);
161 I = --BBIL.erase(I); // remove and delete the malloc instr...
162 Changed = true;
163 ++NumLowered;
164 } else if (FreeInst *FI = dyn_cast<FreeInst>(I)) {
165 Value *PtrCast =
166 new BitCastInst(FI->getOperand(0),
167 PointerType::getUnqual(Type::Int8Ty), "", I);
169 // Insert a call to the free function...
170 CallInst::Create(FreeFunc, PtrCast, "", I)->setTailCall();
172 // Delete the old free instruction
173 I = --BBIL.erase(I);
174 Changed = true;
175 ++NumLowered;
179 return Changed;