Rename MallocFreeHelper as MemoryBuiltins
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85286 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/MemoryBuiltins.cpp b/lib/Analysis/MemoryBuiltins.cpp
new file mode 100644
index 0000000..cf2ad62
--- /dev/null
+++ b/lib/Analysis/MemoryBuiltins.cpp
@@ -0,0 +1,295 @@
+//===------ 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;
+}
+
+static bool isArrayMallocHelper(const CallInst *CI, LLVMContext &Context,
+ const TargetData* TD) {
+ if (!CI)
+ return false;
+
+ const Type* T = getMallocAllocatedType(CI);
+
+ // We can only indentify an array malloc if we know the type of the malloc
+ // call.
+ if (!T) return false;
+
+ Value* MallocArg = CI->getOperand(1);
+ Constant *ElementSize = ConstantExpr::getSizeOf(T);
+ ElementSize = ConstantExpr::getTruncOrBitCast(ElementSize,
+ MallocArg->getType());
+ Constant *FoldedElementSize = ConstantFoldConstantExpression(
+ cast<ConstantExpr>(ElementSize),
+ Context, TD);
+
+
+ if (isa<ConstantExpr>(MallocArg))
+ return (MallocArg != ElementSize);
+
+ BinaryOperator *BI = dyn_cast<BinaryOperator>(MallocArg);
+ if (!BI)
+ return false;
+
+ if (BI->getOpcode() == Instruction::Mul)
+ // ArraySize * ElementSize
+ if (BI->getOperand(1) == ElementSize ||
+ (FoldedElementSize && BI->getOperand(1) == FoldedElementSize))
+ return true;
+
+ // TODO: Detect case where MallocArg mul has been transformed to shl.
+
+ return false;
+}
+
+/// isArrayMalloc - Returns the corresponding CallInst if the instruction
+/// matches the malloc call IR generated by CallInst::CreateMalloc(). This
+/// means that it is a malloc call with one bitcast use AND the malloc call's
+/// size argument is:
+/// 1. a constant not equal to the size of the malloced type
+/// or
+/// 2. the result of a multiplication by the size of the malloced type
+/// Otherwise it returns NULL.
+/// The unique bitcast is needed to determine the type/size of the array
+/// allocation.
+CallInst* llvm::isArrayMalloc(Value* I, LLVMContext &Context,
+ const TargetData* TD) {
+ CallInst *CI = extractMallocCall(I);
+ return (isArrayMallocHelper(CI, Context, TD)) ? CI : NULL;
+}
+
+const CallInst* llvm::isArrayMalloc(const Value* I, LLVMContext &Context,
+ const TargetData* TD) {
+ const CallInst *CI = extractMallocCall(I);
+ return (isArrayMallocHelper(CI, Context, TD)) ? CI : 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;
+}
+
+/// isSafeToGetMallocArraySize - Returns true if the array size of a malloc can
+/// be determined. It can be determined in these 3 cases of malloc codegen:
+/// 1. non-array malloc: The malloc's size argument is a constant and equals the /// size of the type being malloced.
+/// 2. array malloc: This is a malloc call with one bitcast use AND the malloc
+/// call's size argument is a constant multiple of the size of the malloced
+/// type.
+/// 3. array malloc: This is a malloc call with one bitcast use AND the malloc
+/// call's size argument is the result of a multiplication by the size of the
+/// malloced type.
+/// Otherwise returns false.
+static bool isSafeToGetMallocArraySize(const CallInst *CI,
+ LLVMContext &Context,
+ const TargetData* TD) {
+ if (!CI)
+ return false;
+
+ // Type must be known to determine array size.
+ const Type* T = getMallocAllocatedType(CI);
+ if (!T) return false;
+
+ Value* MallocArg = CI->getOperand(1);
+ Constant *ElementSize = ConstantExpr::getSizeOf(T);
+ ElementSize = ConstantExpr::getTruncOrBitCast(ElementSize,
+ MallocArg->getType());
+
+ // First, check if it is a non-array malloc.
+ if (isa<ConstantExpr>(MallocArg) && (MallocArg == ElementSize))
+ return true;
+
+ // Second, check if it can be determined that this is an array malloc.
+ return isArrayMallocHelper(CI, Context, TD);
+}
+
+/// isConstantOne - Return true only if val is constant int 1.
+static bool isConstantOne(Value *val) {
+ return isa<ConstantInt>(val) && cast<ConstantInt>(val)->isOne();
+}
+
+/// getMallocArraySize - Returns the array size of a malloc call. For array
+/// mallocs, the size is computated in 1 of 3 ways:
+/// 1. If the element type is of size 1, then array size is the argument to
+/// malloc.
+/// 2. Else if the malloc's argument is a constant, the array size is that
+/// argument divided by the element type's size.
+/// 3. Else the malloc argument must be a multiplication and the array size is
+/// the first operand of the multiplication.
+/// For non-array mallocs, the computed size is constant 1.
+/// This function returns NULL for all mallocs whose array size cannot be
+/// determined.
+Value* llvm::getMallocArraySize(CallInst* CI, LLVMContext &Context,
+ const TargetData* TD) {
+ if (!isSafeToGetMallocArraySize(CI, Context, TD))
+ return NULL;
+
+ // Match CreateMalloc's use of constant 1 array-size for non-array mallocs.
+ if (!isArrayMalloc(CI, Context, TD))
+ return ConstantInt::get(CI->getOperand(1)->getType(), 1);
+
+ Value* MallocArg = CI->getOperand(1);
+ assert(getMallocAllocatedType(CI) && "getMallocArraySize and no type");
+ Constant *ElementSize = ConstantExpr::getSizeOf(getMallocAllocatedType(CI));
+ ElementSize = ConstantExpr::getTruncOrBitCast(ElementSize,
+ MallocArg->getType());
+
+ Constant* CO = dyn_cast<Constant>(MallocArg);
+ BinaryOperator* BO = dyn_cast<BinaryOperator>(MallocArg);
+ assert((isConstantOne(ElementSize) || CO || BO) &&
+ "getMallocArraySize and malformed malloc IR");
+
+ if (isConstantOne(ElementSize))
+ return MallocArg;
+
+ if (CO)
+ return CO->getOperand(0);
+
+ // TODO: Detect case where MallocArg mul has been transformed to shl.
+
+ assert(BO && "getMallocArraySize not constant but not multiplication either");
+ return BO->getOperand(0);
+}
+
+//===----------------------------------------------------------------------===//
+// 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;
+}