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https://github.com/c64scene-ar/llvm-6502.git
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85480 91177308-0d34-0410-b5e6-96231b3b80d8
280 lines
9.5 KiB
C++
280 lines
9.5 KiB
C++
//===------ MemoryBuiltins.cpp - Identify calls to memory builtins --------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This family of functions identifies calls to builtin functions that allocate
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// or free memory.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/MemoryBuiltins.h"
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#include "llvm/Constants.h"
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#include "llvm/Instructions.h"
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#include "llvm/Module.h"
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#include "llvm/Analysis/ConstantFolding.h"
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using namespace llvm;
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//===----------------------------------------------------------------------===//
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// malloc Call Utility Functions.
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//
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/// isMalloc - Returns true if the the value is either a malloc call or a
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/// bitcast of the result of a malloc call.
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bool llvm::isMalloc(const Value* I) {
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return extractMallocCall(I) || extractMallocCallFromBitCast(I);
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}
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static bool isMallocCall(const CallInst *CI) {
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if (!CI)
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return false;
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const Module* M = CI->getParent()->getParent()->getParent();
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Function *MallocFunc = M->getFunction("malloc");
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if (CI->getOperand(0) != MallocFunc)
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return false;
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// Check malloc prototype.
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// FIXME: workaround for PR5130, this will be obsolete when a nobuiltin
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// attribute will exist.
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const FunctionType *FTy = MallocFunc->getFunctionType();
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if (FTy->getNumParams() != 1)
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return false;
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if (IntegerType *ITy = dyn_cast<IntegerType>(FTy->param_begin()->get())) {
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if (ITy->getBitWidth() != 32 && ITy->getBitWidth() != 64)
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return false;
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return true;
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}
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return false;
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}
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/// extractMallocCall - Returns the corresponding CallInst if the instruction
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/// is a malloc call. Since CallInst::CreateMalloc() only creates calls, we
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/// ignore InvokeInst here.
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const CallInst* llvm::extractMallocCall(const Value* I) {
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const CallInst *CI = dyn_cast<CallInst>(I);
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return (isMallocCall(CI)) ? CI : NULL;
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}
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CallInst* llvm::extractMallocCall(Value* I) {
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CallInst *CI = dyn_cast<CallInst>(I);
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return (isMallocCall(CI)) ? CI : NULL;
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}
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static bool isBitCastOfMallocCall(const BitCastInst* BCI) {
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if (!BCI)
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return false;
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return isMallocCall(dyn_cast<CallInst>(BCI->getOperand(0)));
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}
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/// extractMallocCallFromBitCast - Returns the corresponding CallInst if the
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/// instruction is a bitcast of the result of a malloc call.
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CallInst* llvm::extractMallocCallFromBitCast(Value* I) {
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BitCastInst *BCI = dyn_cast<BitCastInst>(I);
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return (isBitCastOfMallocCall(BCI)) ? cast<CallInst>(BCI->getOperand(0))
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: NULL;
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}
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const CallInst* llvm::extractMallocCallFromBitCast(const Value* I) {
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const BitCastInst *BCI = dyn_cast<BitCastInst>(I);
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return (isBitCastOfMallocCall(BCI)) ? cast<CallInst>(BCI->getOperand(0))
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: NULL;
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}
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/// isConstantOne - Return true only if val is constant int 1.
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static bool isConstantOne(Value *val) {
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return isa<ConstantInt>(val) && cast<ConstantInt>(val)->isOne();
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}
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static Value* isArrayMallocHelper(const CallInst *CI, LLVMContext &Context,
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const TargetData* TD) {
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if (!CI)
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return NULL;
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// Type must be known to determine array size.
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const Type* T = getMallocAllocatedType(CI);
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if (!T)
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return NULL;
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Value* MallocArg = CI->getOperand(1);
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ConstantExpr* CO = dyn_cast<ConstantExpr>(MallocArg);
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BinaryOperator* BO = dyn_cast<BinaryOperator>(MallocArg);
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Constant* ElementSize = ConstantExpr::getSizeOf(T);
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ElementSize = ConstantExpr::getTruncOrBitCast(ElementSize,
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MallocArg->getType());
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Constant *FoldedElementSize =
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ConstantFoldConstantExpression(cast<ConstantExpr>(ElementSize), Context, TD);
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// First, check if CI is a non-array malloc.
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if (CO && ((CO == ElementSize) ||
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(FoldedElementSize && (CO == FoldedElementSize))))
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// Match CreateMalloc's use of constant 1 array-size for non-array mallocs.
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return ConstantInt::get(MallocArg->getType(), 1);
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// Second, check if CI is an array malloc whose array size can be determined.
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if (isConstantOne(ElementSize) ||
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(FoldedElementSize && isConstantOne(FoldedElementSize)))
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return MallocArg;
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if (!CO && !BO)
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return NULL;
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Value* Op0 = NULL;
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Value* Op1 = NULL;
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unsigned Opcode = 0;
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if (CO && ((CO->getOpcode() == Instruction::Mul) ||
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(CO->getOpcode() == Instruction::Shl))) {
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Op0 = CO->getOperand(0);
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Op1 = CO->getOperand(1);
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Opcode = CO->getOpcode();
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}
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if (BO && ((BO->getOpcode() == Instruction::Mul) ||
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(BO->getOpcode() == Instruction::Shl))) {
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Op0 = BO->getOperand(0);
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Op1 = BO->getOperand(1);
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Opcode = BO->getOpcode();
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}
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// Determine array size if malloc's argument is the product of a mul or shl.
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if (Op0) {
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if (Opcode == Instruction::Mul) {
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if ((Op1 == ElementSize) ||
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(FoldedElementSize && (Op1 == FoldedElementSize)))
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// ArraySize * ElementSize
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return Op0;
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if ((Op0 == ElementSize) ||
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(FoldedElementSize && (Op0 == FoldedElementSize)))
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// ElementSize * ArraySize
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return Op1;
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}
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if (Opcode == Instruction::Shl) {
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ConstantInt* Op1Int = dyn_cast<ConstantInt>(Op1);
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if (!Op1Int) return NULL;
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Value* Op1Pow = ConstantInt::get(Op1->getType(),
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pow(2.0, (double) Op1Int->getZExtValue()));
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if (Op0 == ElementSize || (FoldedElementSize && Op0 == FoldedElementSize))
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// ArraySize << log2(ElementSize)
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return Op1Pow;
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if (Op1Pow == ElementSize ||
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(FoldedElementSize && Op1Pow == FoldedElementSize))
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// ElementSize << log2(ArraySize)
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return Op0;
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}
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}
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// We could not determine the malloc array size from MallocArg.
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return NULL;
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}
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/// isArrayMalloc - Returns the corresponding CallInst if the instruction
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/// is a call to malloc whose array size can be determined and the array size
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/// is not constant 1. Otherwise, return NULL.
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CallInst* llvm::isArrayMalloc(Value* I, LLVMContext &Context,
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const TargetData* TD) {
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CallInst *CI = extractMallocCall(I);
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Value* ArraySize = isArrayMallocHelper(CI, Context, TD);
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if (ArraySize &&
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ArraySize != ConstantInt::get(CI->getOperand(1)->getType(), 1))
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return CI;
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// CI is a non-array malloc or we can't figure out that it is an array malloc.
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return NULL;
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}
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const CallInst* llvm::isArrayMalloc(const Value* I, LLVMContext &Context,
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const TargetData* TD) {
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const CallInst *CI = extractMallocCall(I);
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Value* ArraySize = isArrayMallocHelper(CI, Context, TD);
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if (ArraySize &&
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ArraySize != ConstantInt::get(CI->getOperand(1)->getType(), 1))
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return CI;
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// CI is a non-array malloc or we can't figure out that it is an array malloc.
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return NULL;
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}
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/// getMallocType - Returns the PointerType resulting from the malloc call.
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/// This PointerType is the result type of the call's only bitcast use.
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/// If there is no unique bitcast use, then return NULL.
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const PointerType* llvm::getMallocType(const CallInst* CI) {
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assert(isMalloc(CI) && "GetMallocType and not malloc call");
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const BitCastInst* BCI = NULL;
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// Determine if CallInst has a bitcast use.
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for (Value::use_const_iterator UI = CI->use_begin(), E = CI->use_end();
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UI != E; )
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if ((BCI = dyn_cast<BitCastInst>(cast<Instruction>(*UI++))))
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break;
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// Malloc call has 1 bitcast use and no other uses, so type is the bitcast's
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// destination type.
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if (BCI && CI->hasOneUse())
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return cast<PointerType>(BCI->getDestTy());
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// Malloc call was not bitcast, so type is the malloc function's return type.
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if (!BCI)
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return cast<PointerType>(CI->getType());
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// Type could not be determined.
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return NULL;
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}
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/// getMallocAllocatedType - Returns the Type allocated by malloc call. This
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/// Type is the result type of the call's only bitcast use. If there is no
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/// unique bitcast use, then return NULL.
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const Type* llvm::getMallocAllocatedType(const CallInst* CI) {
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const PointerType* PT = getMallocType(CI);
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return PT ? PT->getElementType() : NULL;
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}
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/// getMallocArraySize - Returns the array size of a malloc call. If the
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/// argument passed to malloc is a multiple of the size of the malloced type,
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/// then return that multiple. For non-array mallocs, the multiple is
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/// constant 1. Otherwise, return NULL for mallocs whose array size cannot be
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/// determined.
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Value* llvm::getMallocArraySize(CallInst* CI, LLVMContext &Context,
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const TargetData* TD) {
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return isArrayMallocHelper(CI, Context, TD);
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}
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//===----------------------------------------------------------------------===//
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// free Call Utility Functions.
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//
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/// isFreeCall - Returns true if the the value is a call to the builtin free()
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bool llvm::isFreeCall(const Value* I) {
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const CallInst *CI = dyn_cast<CallInst>(I);
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if (!CI)
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return false;
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const Module* M = CI->getParent()->getParent()->getParent();
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Function *FreeFunc = M->getFunction("free");
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if (CI->getOperand(0) != FreeFunc)
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return false;
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// Check free prototype.
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// FIXME: workaround for PR5130, this will be obsolete when a nobuiltin
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// attribute will exist.
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const FunctionType *FTy = FreeFunc->getFunctionType();
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if (FTy->getReturnType() != Type::getVoidTy(M->getContext()))
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return false;
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if (FTy->getNumParams() != 1)
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return false;
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if (FTy->param_begin()->get() != Type::getInt8PtrTy(M->getContext()))
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return false;
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return true;
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}
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