lib/Analysis/MemoryBuiltins.cpp - fp2-dev/platform/external/llvm - Gitiles

 //===------ MemoryBuiltins.cpp - Identify calls to memory builtins --------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This family of functions identifies calls to builtin functions that allocate
 // or free memory.
 //
 //===----------------------------------------------------------------------===//

 #include "llvm/Analysis/MemoryBuiltins.h"
 #include "llvm/Constants.h"
 #include "llvm/Instructions.h"
 #include "llvm/Module.h"
 #include "llvm/Analysis/ConstantFolding.h"
 using namespace llvm;

 //===----------------------------------------------------------------------===//
 //  malloc Call Utility Functions.
 //

 /// isMalloc - Returns true if the the value is either a malloc call or a
 /// bitcast of the result of a malloc call.
 bool llvm::isMalloc(const Value* I) {
   return extractMallocCall(I) || extractMallocCallFromBitCast(I);
 }

 static bool isMallocCall(const CallInst *CI) {
   if (!CI)
     return false;

   const Module* M = CI->getParent()->getParent()->getParent();
   Function *MallocFunc = M->getFunction("malloc");

   if (CI->getOperand(0) != MallocFunc)
     return false;

   // Check malloc prototype.
   // FIXME: workaround for PR5130, this will be obsolete when a nobuiltin
   // attribute will exist.
   const FunctionType *FTy = MallocFunc->getFunctionType();
   if (FTy->getNumParams() != 1)
     return false;
   if (IntegerType *ITy = dyn_cast<IntegerType>(FTy->param_begin()->get())) {
     if (ITy->getBitWidth() != 32 && ITy->getBitWidth() != 64)
       return false;
     return true;
   }

   return false;
 }

 /// extractMallocCall - Returns the corresponding CallInst if the instruction
 /// is a malloc call.  Since CallInst::CreateMalloc() only creates calls, we
 /// ignore InvokeInst here.
 const CallInst* llvm::extractMallocCall(const Value* I) {
   const CallInst *CI = dyn_cast<CallInst>(I);
   return (isMallocCall(CI)) ? CI : NULL;
 }

 CallInst* llvm::extractMallocCall(Value* I) {
   CallInst *CI = dyn_cast<CallInst>(I);
   return (isMallocCall(CI)) ? CI : NULL;
 }

 static bool isBitCastOfMallocCall(const BitCastInst* BCI) {
   if (!BCI)
     return false;

   return isMallocCall(dyn_cast<CallInst>(BCI->getOperand(0)));
 }

 /// extractMallocCallFromBitCast - Returns the corresponding CallInst if the
 /// instruction is a bitcast of the result of a malloc call.
 CallInst* llvm::extractMallocCallFromBitCast(Value* I) {
   BitCastInst *BCI = dyn_cast<BitCastInst>(I);
   return (isBitCastOfMallocCall(BCI)) ? cast<CallInst>(BCI->getOperand(0))
                                       : NULL;
 }

 const CallInst* llvm::extractMallocCallFromBitCast(const Value* I) {
   const BitCastInst *BCI = dyn_cast<BitCastInst>(I);
   return (isBitCastOfMallocCall(BCI)) ? cast<CallInst>(BCI->getOperand(0))
                                       : NULL;
 }

 /// isConstantOne - Return true only if val is constant int 1.
 static bool isConstantOne(Value *val) {
   return isa<ConstantInt>(val) && cast<ConstantInt>(val)->isOne();
 }

 static Value* isArrayMallocHelper(const CallInst *CI, LLVMContext &Context,
                                   const TargetData* TD) {
   if (!CI)
     return NULL;

   // Type must be known to determine array size.
   const Type* T = getMallocAllocatedType(CI);
   if (!T)
     return NULL;

   Value* MallocArg = CI->getOperand(1);
   ConstantExpr* CO = dyn_cast<ConstantExpr>(MallocArg);
   BinaryOperator* BO = dyn_cast<BinaryOperator>(MallocArg);

   Constant* ElementSize = ConstantExpr::getSizeOf(T);
   ElementSize = ConstantExpr::getTruncOrBitCast(ElementSize,
                                                 MallocArg->getType());
   Constant *FoldedElementSize =
    ConstantFoldConstantExpression(cast<ConstantExpr>(ElementSize), Context, TD);

   // First, check if CI is a non-array malloc.
   if (CO && ((CO == ElementSize) ||
              (FoldedElementSize && (CO == FoldedElementSize))))
     // Match CreateMalloc's use of constant 1 array-size for non-array mallocs.
     return ConstantInt::get(MallocArg->getType(), 1);

   // Second, check if CI is an array malloc whose array size can be determined.
   if (isConstantOne(ElementSize) ||
       (FoldedElementSize && isConstantOne(FoldedElementSize)))
     return MallocArg;

   if (!CO && !BO)
     return NULL;

   Value* Op0 = NULL;
   Value* Op1 = NULL;
   unsigned Opcode = 0;
   if (CO && ((CO->getOpcode() == Instruction::Mul) ||
              (CO->getOpcode() == Instruction::Shl))) {
     Op0 = CO->getOperand(0);
     Op1 = CO->getOperand(1);
     Opcode = CO->getOpcode();
   }
   if (BO && ((BO->getOpcode() == Instruction::Mul) ||
              (BO->getOpcode() == Instruction::Shl))) {
     Op0 = BO->getOperand(0);
     Op1 = BO->getOperand(1);
     Opcode = BO->getOpcode();
   }

   // Determine array size if malloc's argument is the product of a mul or shl.
   if (Op0) {
     if (Opcode == Instruction::Mul) {
       if ((Op1 == ElementSize) ||
           (FoldedElementSize && (Op1 == FoldedElementSize)))
         // ArraySize * ElementSize
         return Op0;
       if ((Op0 == ElementSize) ||
           (FoldedElementSize && (Op0 == FoldedElementSize)))
         // ElementSize * ArraySize
         return Op1;
     }
     if (Opcode == Instruction::Shl) {
       ConstantInt* Op1Int = dyn_cast<ConstantInt>(Op1);
       if (!Op1Int) return NULL;
       Value* Op1Pow = ConstantInt::get(Op1->getType(), (uint64_t)
                                     pow(2.0, (double) Op1Int->getZExtValue()));
       if (Op0 == ElementSize || (FoldedElementSize && Op0 == FoldedElementSize))
         // ArraySize << log2(ElementSize)
         return Op1Pow;
       if (Op1Pow == ElementSize ||
         (FoldedElementSize && Op1Pow == FoldedElementSize))
         // ElementSize << log2(ArraySize)
         return Op0;
     }
   }

   // We could not determine the malloc array size from MallocArg.
   return NULL;
 }

 /// isArrayMalloc - Returns the corresponding CallInst if the instruction
 /// is a call to malloc whose array size can be determined and the array size
 /// is not constant 1.  Otherwise, return NULL.
 CallInst* llvm::isArrayMalloc(Value* I, LLVMContext &Context,
                               const TargetData* TD) {
   CallInst *CI = extractMallocCall(I);
   Value* ArraySize = isArrayMallocHelper(CI, Context, TD);

   if (ArraySize &&
       ArraySize != ConstantInt::get(CI->getOperand(1)->getType(), 1))
     return CI;

   // CI is a non-array malloc or we can't figure out that it is an array malloc.
   return NULL;
 }

 const CallInst* llvm::isArrayMalloc(const Value* I, LLVMContext &Context,
                                     const TargetData* TD) {
   const CallInst *CI = extractMallocCall(I);
   Value* ArraySize = isArrayMallocHelper(CI, Context, TD);

   if (ArraySize &&
       ArraySize != ConstantInt::get(CI->getOperand(1)->getType(), 1))
     return CI;

   // CI is a non-array malloc or we can't figure out that it is an array malloc.
   return NULL;
 }

 /// getMallocType - Returns the PointerType resulting from the malloc call.
 /// This PointerType is the result type of the call's only bitcast use.
 /// If there is no unique bitcast use, then return NULL.
 const PointerType* llvm::getMallocType(const CallInst* CI) {
   assert(isMalloc(CI) && "GetMallocType and not malloc call");

   const BitCastInst* BCI = NULL;

   // Determine if CallInst has a bitcast use.
   for (Value::use_const_iterator UI = CI->use_begin(), E = CI->use_end();
        UI != E; )
     if ((BCI = dyn_cast<BitCastInst>(cast<Instruction>(*UI++))))
       break;

   // Malloc call has 1 bitcast use and no other uses, so type is the bitcast's
   // destination type.
   if (BCI && CI->hasOneUse())
     return cast<PointerType>(BCI->getDestTy());

   // Malloc call was not bitcast, so type is the malloc function's return type.
   if (!BCI)
     return cast<PointerType>(CI->getType());

   // Type could not be determined.
   return NULL;
 }

 /// getMallocAllocatedType - Returns the Type allocated by malloc call. This
 /// Type is the result type of the call's only bitcast use. If there is no
 /// unique bitcast use, then return NULL.
 const Type* llvm::getMallocAllocatedType(const CallInst* CI) {
   const PointerType* PT = getMallocType(CI);
   return PT ? PT->getElementType() : NULL;
 }

 /// getMallocArraySize - Returns the array size of a malloc call.  If the
 /// argument passed to malloc is a multiple of the size of the malloced type,
 /// then return that multiple.  For non-array mallocs, the multiple is
 /// constant 1.  Otherwise, return NULL for mallocs whose array size cannot be
 /// determined.
 Value* llvm::getMallocArraySize(CallInst* CI, LLVMContext &Context,
                                 const TargetData* TD) {
   return isArrayMallocHelper(CI, Context, TD);
 }

 //===----------------------------------------------------------------------===//
 //  free Call Utility Functions.
 //

 /// isFreeCall - Returns true if the the value is a call to the builtin free()
 bool llvm::isFreeCall(const Value* I) {
   const CallInst *CI = dyn_cast<CallInst>(I);
   if (!CI)
     return false;

   const Module* M = CI->getParent()->getParent()->getParent();
   Function *FreeFunc = M->getFunction("free");

   if (CI->getOperand(0) != FreeFunc)
     return false;

   // Check free prototype.
   // FIXME: workaround for PR5130, this will be obsolete when a nobuiltin
   // attribute will exist.
   const FunctionType *FTy = FreeFunc->getFunctionType();
   if (FTy->getReturnType() != Type::getVoidTy(M->getContext()))
     return false;
   if (FTy->getNumParams() != 1)
     return false;
   if (FTy->param_begin()->get() != Type::getInt8PtrTy(M->getContext()))
     return false;

   return true;
 }
	//===------ MemoryBuiltins.cpp - Identify calls to memory builtins --------===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//
	//
	// This family of functions identifies calls to builtin functions that allocate
	// or free memory.
	//
	//===----------------------------------------------------------------------===//

	#include "llvm/Analysis/MemoryBuiltins.h"
	#include "llvm/Constants.h"
	#include "llvm/Instructions.h"
	#include "llvm/Module.h"
	#include "llvm/Analysis/ConstantFolding.h"
	using namespace llvm;

	//===----------------------------------------------------------------------===//
	// malloc Call Utility Functions.
	//

	/// isMalloc - Returns true if the the value is either a malloc call or a
	/// bitcast of the result of a malloc call.
	bool llvm::isMalloc(const Value* I) {
	return extractMallocCall(I) \|\| extractMallocCallFromBitCast(I);
	}

	static bool isMallocCall(const CallInst *CI) {
	if (!CI)
	return false;

	const Module* M = CI->getParent()->getParent()->getParent();
	Function *MallocFunc = M->getFunction("malloc");

	if (CI->getOperand(0) != MallocFunc)
	return false;

	// Check malloc prototype.
	// FIXME: workaround for PR5130, this will be obsolete when a nobuiltin
	// attribute will exist.
	const FunctionType *FTy = MallocFunc->getFunctionType();
	if (FTy->getNumParams() != 1)
	return false;
	if (IntegerType *ITy = dyn_cast<IntegerType>(FTy->param_begin()->get())) {
	if (ITy->getBitWidth() != 32 && ITy->getBitWidth() != 64)
	return false;
	return true;
	}

	return false;
	}

	/// extractMallocCall - Returns the corresponding CallInst if the instruction
	/// is a malloc call. Since CallInst::CreateMalloc() only creates calls, we
	/// ignore InvokeInst here.
	const CallInst* llvm::extractMallocCall(const Value* I) {
	const CallInst *CI = dyn_cast<CallInst>(I);
	return (isMallocCall(CI)) ? CI : NULL;
	}

	CallInst* llvm::extractMallocCall(Value* I) {
	CallInst *CI = dyn_cast<CallInst>(I);
	return (isMallocCall(CI)) ? CI : NULL;
	}

	static bool isBitCastOfMallocCall(const BitCastInst* BCI) {
	if (!BCI)
	return false;

	return isMallocCall(dyn_cast<CallInst>(BCI->getOperand(0)));
	}

	/// extractMallocCallFromBitCast - Returns the corresponding CallInst if the
	/// instruction is a bitcast of the result of a malloc call.
	CallInst* llvm::extractMallocCallFromBitCast(Value* I) {
	BitCastInst *BCI = dyn_cast<BitCastInst>(I);
	return (isBitCastOfMallocCall(BCI)) ? cast<CallInst>(BCI->getOperand(0))
	: NULL;
	}

	const CallInst* llvm::extractMallocCallFromBitCast(const Value* I) {
	const BitCastInst *BCI = dyn_cast<BitCastInst>(I);
	return (isBitCastOfMallocCall(BCI)) ? cast<CallInst>(BCI->getOperand(0))
	: NULL;
	}

	/// isConstantOne - Return true only if val is constant int 1.
	static bool isConstantOne(Value *val) {
	return isa<ConstantInt>(val) && cast<ConstantInt>(val)->isOne();
	}

	static Value* isArrayMallocHelper(const CallInst *CI, LLVMContext &Context,
	const TargetData* TD) {
	if (!CI)
	return NULL;

	// Type must be known to determine array size.
	const Type* T = getMallocAllocatedType(CI);
	if (!T)
	return NULL;

	Value* MallocArg = CI->getOperand(1);
	ConstantExpr* CO = dyn_cast<ConstantExpr>(MallocArg);
	BinaryOperator* BO = dyn_cast<BinaryOperator>(MallocArg);

	Constant* ElementSize = ConstantExpr::getSizeOf(T);
	ElementSize = ConstantExpr::getTruncOrBitCast(ElementSize,
	MallocArg->getType());
	Constant *FoldedElementSize =
	ConstantFoldConstantExpression(cast<ConstantExpr>(ElementSize), Context, TD);

	// First, check if CI is a non-array malloc.
	if (CO && ((CO == ElementSize) \|\|
	(FoldedElementSize && (CO == FoldedElementSize))))
	// Match CreateMalloc's use of constant 1 array-size for non-array mallocs.
	return ConstantInt::get(MallocArg->getType(), 1);

	// Second, check if CI is an array malloc whose array size can be determined.
	if (isConstantOne(ElementSize) \|\|
	(FoldedElementSize && isConstantOne(FoldedElementSize)))
	return MallocArg;

	if (!CO && !BO)
	return NULL;

	Value* Op0 = NULL;
	Value* Op1 = NULL;
	unsigned Opcode = 0;
	if (CO && ((CO->getOpcode() == Instruction::Mul) \|\|
	(CO->getOpcode() == Instruction::Shl))) {
	Op0 = CO->getOperand(0);
	Op1 = CO->getOperand(1);
	Opcode = CO->getOpcode();
	}
	if (BO && ((BO->getOpcode() == Instruction::Mul) \|\|
	(BO->getOpcode() == Instruction::Shl))) {
	Op0 = BO->getOperand(0);
	Op1 = BO->getOperand(1);
	Opcode = BO->getOpcode();
	}

	// Determine array size if malloc's argument is the product of a mul or shl.
	if (Op0) {
	if (Opcode == Instruction::Mul) {
	if ((Op1 == ElementSize) \|\|
	(FoldedElementSize && (Op1 == FoldedElementSize)))
	// ArraySize * ElementSize
	return Op0;
	if ((Op0 == ElementSize) \|\|
	(FoldedElementSize && (Op0 == FoldedElementSize)))
	// ElementSize * ArraySize
	return Op1;
	}
	if (Opcode == Instruction::Shl) {
	ConstantInt* Op1Int = dyn_cast<ConstantInt>(Op1);
	if (!Op1Int) return NULL;
	Value* Op1Pow = ConstantInt::get(Op1->getType(), (uint64_t)
	pow(2.0, (double) Op1Int->getZExtValue()));
	if (Op0 == ElementSize \|\| (FoldedElementSize && Op0 == FoldedElementSize))
	// ArraySize << log2(ElementSize)
	return Op1Pow;
	if (Op1Pow == ElementSize \|\|
	(FoldedElementSize && Op1Pow == FoldedElementSize))
	// ElementSize << log2(ArraySize)
	return Op0;
	}
	}

	// We could not determine the malloc array size from MallocArg.
	return NULL;
	}

	/// isArrayMalloc - Returns the corresponding CallInst if the instruction
	/// is a call to malloc whose array size can be determined and the array size
	/// is not constant 1. Otherwise, return NULL.
	CallInst* llvm::isArrayMalloc(Value* I, LLVMContext &Context,
	const TargetData* TD) {
	CallInst *CI = extractMallocCall(I);
	Value* ArraySize = isArrayMallocHelper(CI, Context, TD);

	if (ArraySize &&
	ArraySize != ConstantInt::get(CI->getOperand(1)->getType(), 1))
	return CI;

	// CI is a non-array malloc or we can't figure out that it is an array malloc.
	return NULL;
	}

	const CallInst* llvm::isArrayMalloc(const Value* I, LLVMContext &Context,
	const TargetData* TD) {
	const CallInst *CI = extractMallocCall(I);
	Value* ArraySize = isArrayMallocHelper(CI, Context, TD);

	if (ArraySize &&
	ArraySize != ConstantInt::get(CI->getOperand(1)->getType(), 1))
	return CI;

	// CI is a non-array malloc or we can't figure out that it is an array malloc.
	return NULL;
	}

	/// getMallocType - Returns the PointerType resulting from the malloc call.
	/// This PointerType is the result type of the call's only bitcast use.
	/// If there is no unique bitcast use, then return NULL.
	const PointerType* llvm::getMallocType(const CallInst* CI) {
	assert(isMalloc(CI) && "GetMallocType and not malloc call");

	const BitCastInst* BCI = NULL;

	// Determine if CallInst has a bitcast use.
	for (Value::use_const_iterator UI = CI->use_begin(), E = CI->use_end();
	UI != E; )
	if ((BCI = dyn_cast<BitCastInst>(cast<Instruction>(*UI++))))
	break;

	// Malloc call has 1 bitcast use and no other uses, so type is the bitcast's
	// destination type.
	if (BCI && CI->hasOneUse())
	return cast<PointerType>(BCI->getDestTy());

	// Malloc call was not bitcast, so type is the malloc function's return type.
	if (!BCI)
	return cast<PointerType>(CI->getType());

	// Type could not be determined.
	return NULL;
	}

	/// getMallocAllocatedType - Returns the Type allocated by malloc call. This
	/// Type is the result type of the call's only bitcast use. If there is no
	/// unique bitcast use, then return NULL.
	const Type* llvm::getMallocAllocatedType(const CallInst* CI) {
	const PointerType* PT = getMallocType(CI);
	return PT ? PT->getElementType() : NULL;
	}

	/// getMallocArraySize - Returns the array size of a malloc call. If the
	/// argument passed to malloc is a multiple of the size of the malloced type,
	/// then return that multiple. For non-array mallocs, the multiple is
	/// constant 1. Otherwise, return NULL for mallocs whose array size cannot be
	/// determined.
	Value* llvm::getMallocArraySize(CallInst* CI, LLVMContext &Context,
	const TargetData* TD) {
	return isArrayMallocHelper(CI, Context, TD);
	}

	//===----------------------------------------------------------------------===//
	// free Call Utility Functions.
	//

	/// isFreeCall - Returns true if the the value is a call to the builtin free()
	bool llvm::isFreeCall(const Value* I) {
	const CallInst *CI = dyn_cast<CallInst>(I);
	if (!CI)
	return false;

	const Module* M = CI->getParent()->getParent()->getParent();
	Function *FreeFunc = M->getFunction("free");

	if (CI->getOperand(0) != FreeFunc)
	return false;

	// Check free prototype.
	// FIXME: workaround for PR5130, this will be obsolete when a nobuiltin
	// attribute will exist.
	const FunctionType *FTy = FreeFunc->getFunctionType();
	if (FTy->getReturnType() != Type::getVoidTy(M->getContext()))
	return false;
	if (FTy->getNumParams() != 1)
	return false;
	if (FTy->param_begin()->get() != Type::getInt8PtrTy(M->getContext()))
	return false;

	return true;
	}