Add malloc call utility functions. Patch by Victor Hernandez.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@81426 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 417 insertions, 52 deletions

diff --git a/include/llvm/Analysis/MallocHelper.h b/include/llvm/Analysis/MallocHelper.h
new file mode 100644
index 0000000000..06959ab6b3
--- /dev/null
+++ b/include/llvm/Analysis/MallocHelper.h
@@ -0,0 +1,86 @@
+//===- llvm/Analysis/MallocHelper.h ---- Identify malloc calls --*- C++ -*-===//
+//
+//                     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 malloc, bitcasts of malloc
+// calls, and the types and array sizes associated with them.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_MALLOCHELPER_H
+#define LLVM_ANALYSIS_MALLOCHELPER_H
+
+namespace llvm {
+class BitCastInst;
+class CallInst;
+class Instruction;
+class PointerType;
+class Twine;
+class Type;
+class Value;
+
+//===----------------------------------------------------------------------===//
+//  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 isMalloc(const Value* I);
+bool isMalloc(Value* I);
+
+/// extractMallocCall - Returns the corresponding CallInst if the instruction
+/// is a malloc call.  Since CallInst::CreateMalloc() only creates calls, we
+/// ignore InvokeInst here.
+const CallInst* extractMallocCall(const Value* I);
+CallInst* extractMallocCall(Value* I);
+
+/// extractMallocCallFromBitCast - Returns the corresponding CallInst if the
+/// instruction is a bitcast of the result of a malloc call.
+const CallInst* extractMallocCallFromBitCast(const Value* I);
+CallInst* extractMallocCallFromBitCast(Value* I);
+
+/// 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 malloc's allocated type
+/// or
+///  2. the result of a multiplication by the malloc's allocated type
+/// Otherwise it returns NULL.
+/// The unique bitcast is needed to determine the type/size of the array
+/// allocation.
+CallInst* isArrayMalloc(Value* I);
+const CallInst* isArrayMalloc(const Value* I);
+
+/// 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* getMallocType(const CallInst* CI);
+
+/// 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* getMallocAllocatedType(const CallInst* CI);
+
+/// getMallocArraySize - Returns the array size of a malloc call.  The array
+/// size is computated in 1 of 3 ways:
+///  1. If the element type if 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.
+/// This function returns constant 1 if:
+///  1. The malloc call's allocated type cannot be determined.
+///  2. IR wasn't created by a call to CallInst::CreateMalloc() with a non-NULL
+///     ArraySize.
+Value* getMallocArraySize(CallInst* CI);
+
+} // End llvm namespace
+
+#endif
diff --git a/include/llvm/Instructions.h b/include/llvm/Instructions.h
index e208f37868..637e3555fb 100644
--- a/include/llvm/Instructions.h
+++ b/include/llvm/Instructions.h
@@ -1033,6 +1033,18 @@ public:
                           BasicBlock *InsertAtEnd) {
     return new(1) CallInst(F, NameStr, InsertAtEnd);
   }
+  /// CreateMalloc - Generate the IR for a call to malloc:
+  /// 1. Compute the malloc call's argument as the specified type's size,
+  ///    possibly multiplied by the array size if the array size is not
+  ///    constant 1.
+  /// 2. Call malloc with that argument.
+  /// 3. Bitcast the result of the malloc call to the specified type.
+  static Value *CreateMalloc(Instruction *I,
+                             const Type *AllocTy, const Type *IntPtrTy,
+                             Value *ArraySize = 0, const Twine &NameStr = "");
+  static Value *CreateMalloc(BasicBlock *InsertAtEnd,
+                             const Type *AllocTy, const Type *IntPtrTy,
+                             Value *ArraySize = 0, const Twine &NameStr = "");
 
   ~CallInst();
 
diff --git a/lib/Analysis/MallocHelper.cpp b/lib/Analysis/MallocHelper.cpp
new file mode 100644
index 0000000000..5001110c6a
--- /dev/null
+++ b/lib/Analysis/MallocHelper.cpp
@@ -0,0 +1,202 @@
+//===-- MallocHelper.cpp - Functions to identify malloc calls -------------===//
+//
+//                     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 malloc, bitcasts of malloc
+// calls, and the types and array sizes associated with them.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/MallocHelper.h"
+#include "llvm/Constants.h"
+#include "llvm/Instructions.h"
+#include "llvm/Module.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(Value* I) {
+  return extractMallocCall(I) || extractMallocCallFromBitCast(I);
+}
+
+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();
+  Constant *MallocFunc = M->getFunction("malloc");
+
+  if (CI->getOperand(0) != MallocFunc)
+    return false;
+
+  return true;
+}
+
+/// 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) {
+  if (!CI)
+    return false;
+
+  // Only identify array mallocs for mallocs with 1 bitcast use.  The unique 
+  // bitcast is needed to determine the type/size of the array allocation.
+  if (!CI->hasOneUse()) return false;
+
+  for (Value::use_const_iterator UI = CI->use_begin(), E = CI->use_end();
+       UI != E; )
+    if (!isa<BitCastInst>(cast<Instruction>(*UI++)))
+      return false;
+
+  // malloc arg
+  Value* MallocArg = CI->getOperand(1);
+  // element size
+  const Type* T = getMallocAllocatedType(CI);
+  if (!T) return false;
+  Constant *ElementSize = ConstantExpr::getSizeOf(T);
+  
+  if (isa<ConstantExpr>(MallocArg))
+    return (MallocArg == ElementSize) ? false : true;
+
+  BinaryOperator *BI = dyn_cast<BinaryOperator>(MallocArg);
+  if (!BI)
+    return false;
+
+  if (BI->getOpcode() != Instruction::Mul)
+    return false;
+      
+  if (BI->getOperand(1) != ElementSize)
+    return false;
+        
+  return true;
+}
+
+/// 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 malloc's allocated type
+/// or
+///  2. the result of a multiplication by the malloc's allocated type
+/// Otherwise it returns NULL.
+/// The unique bitcast is needed to determine the type/size of the array
+/// allocation.
+CallInst* llvm::isArrayMalloc(Value* I) {
+  CallInst *CI = extractMallocCall(I);
+  return (isArrayMallocHelper(CI)) ? CI : NULL;
+}
+
+const CallInst* llvm::isArrayMalloc(const Value* I) {
+  const CallInst *CI = extractMallocCall(I);
+  return (isArrayMallocHelper(CI)) ? 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 type only if there is only 1 bitcast use of CI.
+  if (CI->hasOneUse())
+    for (Value::use_const_iterator UI = CI->use_begin(), E = CI->use_end();
+         UI != E; )
+      BCI = dyn_cast<BitCastInst>(cast<Instruction>(*UI++));
+
+  return BCI ? reinterpret_cast<const PointerType*>(BCI->getDestTy()) : 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;
+}
+
+/// 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.  The array
+/// size is computated in 1 of 3 ways:
+///  1. If the element type if 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.
+/// This function returns constant 1 if:
+///  1. The malloc call's allocated type cannot be determined.
+///  2. IR wasn't created by a call to CallInst::CreateMalloc() with a non-NULL
+///     ArraySize.
+Value* llvm::getMallocArraySize(CallInst* CI) {
+  // Match CreateMalloc's use of constant 1 array-size for non-array mallocs.
+  if (!isArrayMalloc(CI))
+    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(cast<Constant>(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 ConstantExpr::getUDiv(CO, ElementSize);
+  
+  assert(BO && "getMallocArraySize not constant but not multiplication either");
+  return BO->getOperand(0);
+}
diff --git a/lib/Transforms/Utils/LowerAllocations.cpp b/lib/Transforms/Utils/LowerAllocations.cpp
index 7276d55fc4..cc1f6ea5e5 100644
--- a/lib/Transforms/Utils/LowerAllocations.cpp
+++ b/lib/Transforms/Utils/LowerAllocations.cpp
@@ -33,13 +33,13 @@ namespace {
   /// @free calls.
   ///
   class VISIBILITY_HIDDEN LowerAllocations : public BasicBlockPass {
-    Constant *MallocFunc;   // Functions in the module we are processing
-    Constant *FreeFunc;     // Initialized by doInitialization
+    Constant *FreeFunc;   // Functions in the module we are processing
+                          // Initialized by doInitialization
     bool LowerMallocArgToInteger;
   public:
     static char ID; // Pass ID, replacement for typeid
     explicit LowerAllocations(bool LowerToInt = false)
-      : BasicBlockPass(&ID), MallocFunc(0), FreeFunc(0), 
+      : BasicBlockPass(&ID), FreeFunc(0), 
         LowerMallocArgToInteger(LowerToInt) {}
 
     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
@@ -88,10 +88,6 @@ Pass *llvm::createLowerAllocationsPass(bool LowerMallocArgToInteger) {
 //
 bool LowerAllocations::doInitialization(Module &M) {
   const Type *BPTy = PointerType::getUnqual(Type::getInt8Ty(M.getContext()));
-  // Prototype malloc as "char* malloc(...)", because we don't know in
-  // doInitialization whether size_t is int or long.
-  FunctionType *FT = FunctionType::get(BPTy, true);
-  MallocFunc = M.getOrInsertFunction("malloc", FT);
   FreeFunc = M.getOrInsertFunction("free"  , Type::getVoidTy(M.getContext()),
                                    BPTy, (Type *)0);
   return true;
@@ -102,7 +98,7 @@ bool LowerAllocations::doInitialization(Module &M) {
 //
 bool LowerAllocations::runOnBasicBlock(BasicBlock &BB) {
   bool Changed = false;
-  assert(MallocFunc && FreeFunc && "Pass not initialized!");
+  assert(FreeFunc && "Pass not initialized!");
 
   BasicBlock::InstListType &BBIL = BB.getInstList();
 
@@ -112,50 +108,8 @@ bool LowerAllocations::runOnBasicBlock(BasicBlock &BB) {
   // Loop over all of the instructions, looking for malloc or free instructions
   for (BasicBlock::iterator I = BB.begin(), E = BB.end(); I != E; ++I) {
     if (MallocInst *MI = dyn_cast<MallocInst>(I)) {
-      const Type *AllocTy = MI->getType()->getElementType();
-
-      // malloc(type) becomes i8 *malloc(size)
-      Value *MallocArg;
-      if (LowerMallocArgToInteger)
-        MallocArg = ConstantInt::get(Type::getInt64Ty(BB.getContext()),
-                                     TD.getTypeAllocSize(AllocTy));
-      else
-        MallocArg = ConstantExpr::getSizeOf(AllocTy);
-      MallocArg =
-           ConstantExpr::getTruncOrBitCast(cast<Constant>(MallocArg), 
-                                                  IntPtrTy);
-
-      if (MI->isArrayAllocation()) {
-        if (isa<ConstantInt>(MallocArg) &&
-            cast<ConstantInt>(MallocArg)->isOne()) {
-          MallocArg = MI->getOperand(0);         // Operand * 1 = Operand
-        } else if (Constant *CO = dyn_cast<Constant>(MI->getOperand(0))) {
-          CO =
-              ConstantExpr::getIntegerCast(CO, IntPtrTy, false /*ZExt*/);
-          MallocArg = ConstantExpr::getMul(CO, 
-                                                  cast<Constant>(MallocArg));
-        } else {
-          Value *Scale = MI->getOperand(0);
-          if (Scale->getType() != IntPtrTy)
-            Scale = CastInst::CreateIntegerCast(Scale, IntPtrTy, false /*ZExt*/,
-                                                "", I);
-
-          // Multiply it by the array size if necessary...
-          MallocArg = BinaryOperator::Create(Instruction::Mul, Scale,
-                                             MallocArg, "", I);
-        }
-      }
-
-      // Create the call to Malloc.
-      CallInst *MCall = CallInst::Create(MallocFunc, MallocArg, "", I);
-      MCall->setTailCall();
-
-      // Create a cast instruction to convert to the right type...
-      Value *MCast;
-      if (MCall->getType() != Type::getVoidTy(BB.getContext()))
-        MCast = new BitCastInst(MCall, MI->getType(), "", I);
-      else
-        MCast = Constant::getNullValue(MI->getType());
+      Value *MCast = CallInst::CreateMalloc(I, MI->getType(), IntPtrTy,
+                                            MI->getOperand(0));
 
       // Replace all uses of the old malloc inst with the cast inst
       MI->replaceAllUsesWith(MCast);
diff --git a/lib/VMCore/Instructions.cpp b/lib/VMCore/Instructions.cpp
index 9d8e0477ee..a03587107c 100644
--- a/lib/VMCore/Instructions.cpp
+++ b/lib/VMCore/Instructions.cpp
@@ -16,6 +16,7 @@
 #include "llvm/DerivedTypes.h"
 #include "llvm/Function.h"
 #include "llvm/Instructions.h"
+#include "llvm/Module.h"
 #include "llvm/Operator.h"
 #include "llvm/Analysis/Dominators.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -440,6 +441,116 @@ bool CallInst::paramHasAttr(unsigned i, Attributes attr) const {
   return false;
 }
 
+/// IsConstantOne - Return true only if val is constant int 1
+static bool IsConstantOne(Value *val) {
+  assert(val && "IsConstantOne does not work with NULL val");
+  return isa<ConstantInt>(val) && cast<ConstantInt>(val)->isOne();
+}
+
+static Value *checkArraySize(Value *Amt, const Type *IntPtrTy) {
+  if (!Amt)
+    Amt = ConstantInt::get(IntPtrTy, 1);
+  else {
+    assert(!isa<BasicBlock>(Amt) &&
+           "Passed basic block into malloc size parameter! Use other ctor");
+    assert(Amt->getType() == IntPtrTy &&
+           "Malloc array size is not an intptr!");
+  }
+  return Amt;
+}
+
+static Value *createMalloc(Instruction *InsertBefore, BasicBlock *InsertAtEnd,
+                           const Type *AllocTy, const Type *IntPtrTy,
+                           Value *ArraySize, const Twine &NameStr) {
+  assert((!InsertBefore && InsertAtEnd || InsertBefore && !InsertAtEnd) &&
+         "createMalloc needs only InsertBefore or InsertAtEnd");
+  const PointerType *AllocPtrType = dyn_cast<PointerType>(AllocTy);
+  assert(AllocPtrType && "CreateMalloc passed a non-pointer allocation type");
+  
+  ArraySize = checkArraySize(ArraySize, IntPtrTy);
+
+  // malloc(type) becomes i8 *malloc(size)
+  Value *AllocSize = ConstantExpr::getSizeOf(AllocPtrType->getElementType());
+  AllocSize = ConstantExpr::getTruncOrBitCast(cast<Constant>(AllocSize), 
+                                              IntPtrTy);
+  if (!IsConstantOne(ArraySize))
+    if (IsConstantOne(AllocSize)) {
+      AllocSize = ArraySize;         // Operand * 1 = Operand
+    } else if (Constant *CO = dyn_cast<Constant>(ArraySize)) {
+      Constant *Scale = ConstantExpr::getIntegerCast(CO, IntPtrTy,
+                                                     false /*ZExt*/);
+      // Malloc arg is constant product of type size and array size
+      AllocSize = ConstantExpr::getMul(Scale, cast<Constant>(AllocSize));
+    } else {
+      Value *Scale = ArraySize;
+      if (Scale->getType() != IntPtrTy)
+        if (InsertBefore)
+          Scale = CastInst::CreateIntegerCast(Scale, IntPtrTy, false /*ZExt*/,
+                                              "", InsertBefore);
+        else
+          Scale = CastInst::CreateIntegerCast(Scale, IntPtrTy, false /*ZExt*/,
+                                              "", InsertAtEnd);
+      // Multiply type size by the array size...
+      if (InsertBefore)
+        AllocSize = BinaryOperator::CreateMul(Scale, AllocSize,
+                                              "", InsertBefore);
+      else
+        AllocSize = BinaryOperator::CreateMul(Scale, AllocSize,
+                                              "", InsertAtEnd);
+    }
+
+  // Create the call to Malloc.
+  BasicBlock* BB = InsertBefore ? InsertBefore->getParent() : InsertAtEnd;
+  Module* M = BB->getParent()->getParent();
+  const Type *BPTy = PointerType::getUnqual(Type::getInt8Ty(BB->getContext()));
+  // prototype malloc as "void *malloc(size_t)"
+  Constant *MallocFunc = M->getOrInsertFunction("malloc", BPTy, 
+                                                IntPtrTy, NULL);
+  CallInst *MCall = NULL;
+  if (InsertBefore) 
+    MCall = CallInst::Create(MallocFunc, AllocSize, NameStr, InsertBefore);
+  else
+    MCall = CallInst::Create(MallocFunc, AllocSize, NameStr, InsertAtEnd);
+  MCall->setTailCall();
+
+  // Create a cast instruction to convert to the right type...
+  const Type* VoidT = Type::getVoidTy(BB->getContext());
+  assert(MCall->getType() != VoidT && "Malloc has void return type");
+  Value *MCast;
+  if (InsertBefore)
+    MCast = new BitCastInst(MCall, AllocPtrType, NameStr, InsertBefore);
+  else
+    MCast = new BitCastInst(MCall, AllocPtrType, NameStr);
+  return MCast;
+}
+
+/// CreateMalloc - Generate the IR for a call to malloc:
+/// 1. Compute the malloc call's argument as the specified type's size,
+///    possibly multiplied by the array size if the array size is not
+///    constant 1.
+/// 2. Call malloc with that argument.
+/// 3. Bitcast the result of the malloc call to the specified type.
+Value *CallInst::CreateMalloc(Instruction *InsertBefore,
+                              const Type *AllocTy, const Type *IntPtrTy,
+                              Value *ArraySize, const Twine &NameStr) {
+  return createMalloc(InsertBefore, NULL, AllocTy,
+                      IntPtrTy, ArraySize, NameStr);
+}
+
+/// CreateMalloc - Generate the IR for a call to malloc:
+/// 1. Compute the malloc call's argument as the specified type's size,
+///    possibly multiplied by the array size if the array size is not
+///    constant 1.
+/// 2. Call malloc with that argument.
+/// 3. Bitcast the result of the malloc call to the specified type.
+/// Note: This function does not add the bitcast to the basic block, that is the
+/// responsibility of the caller.
+Value *CallInst::CreateMalloc(BasicBlock *InsertAtEnd,
+                              const Type *AllocTy, const Type *IntPtrTy,
+                              Value *ArraySize, const Twine &NameStr) {
+  return createMalloc(NULL, InsertAtEnd, AllocTy, 
+                      IntPtrTy, ArraySize, NameStr);
+}
 
 //===----------------------------------------------------------------------===//
 //                        InvokeInst Implementation