1 files changed, 277 insertions, 0 deletions
diff --git a/lib/Analysis/MemoryBuiltins.cpp b/lib/Analysis/MemoryBuiltins.cpp
new file mode 100644
index 0000000..e710350
--- /dev/null
+++ b/lib/Analysis/MemoryBuiltins.cpp
@@ -0,0 +1,277 @@
+//===------ 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;
+
+  Function *Callee = CI->getCalledFunction();
+  if (Callee == 0 || !Callee->isDeclaration() || Callee->getName() != "malloc")
+    return false;
+
+  // Check malloc prototype.
+  // FIXME: workaround for PR5130, this will be obsolete when a nobuiltin 
+  // attribute will exist.
+  const FunctionType *FTy = Callee->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 *Op1CI = dyn_cast<ConstantInt>(Op1);
+      if (!Op1CI) return NULL;
+      
+      APInt Op1Int = Op1CI->getValue();
+      uint64_t BitToSet = Op1Int.getLimitedValue(Op1Int.getBitWidth() - 1);
+      Value *Op1Pow = ConstantInt::get(Context, 
+                                  APInt(Op1Int.getBitWidth(), 0).set(BitToSet));
+      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;
+  Function *Callee = CI->getCalledFunction();
+  if (Callee == 0 || !Callee->isDeclaration() || Callee->getName() != "free")
+    return false;
+
+  // Check free prototype.
+  // FIXME: workaround for PR5130, this will be obsolete when a nobuiltin 
+  // attribute will exist.
+  const FunctionType *FTy = Callee->getFunctionType();
+  if (!FTy->getReturnType()->isVoidTy())
+    return false;
+  if (FTy->getNumParams() != 1)
+    return false;
+  if (FTy->param_begin()->get() != Type::getInt8PtrTy(Callee->getContext()))
+    return false;
+
+  return true;
+}