Enhance analysis passes so that they apply the same analysis to malloc calls as to MallocInst.

Reviewed by Eli Friedman.

llvm-svn: 82281

lib/Analysis/BasicAliasAnalysis.cpp

@@ -15,6 +15,7 @@
 
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Analysis/CaptureTracking.h"
+#include "llvm/Analysis/MallocHelper.h"
 #include "llvm/Analysis/Passes.h"
 #include "llvm/Constants.h"
 #include "llvm/DerivedTypes.h"
@@ -102,7 +103,7 @@ static bool isNonEscapingLocalObject(const Value *V) {
 /// isObjectSmallerThan - Return true if we can prove that the object specified
 /// by V is smaller than Size.
 static bool isObjectSmallerThan(const Value *V, unsigned Size,
-                                const TargetData &TD) {
+                                LLVMContext &Context, const TargetData &TD) {
   const Type *AccessTy;
   if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(V)) {
     AccessTy = GV->getType()->getElementType();
@@ -111,6 +112,12 @@ static bool isObjectSmallerThan(const Value *V, unsigned Size,
       AccessTy = AI->getType()->getElementType();
     else
       return false;
+  } else if (const CallInst* CI = extractMallocCall(V)) {
+    if (!isArrayMalloc(V, Context, &TD))
+      // The size is the argument to the malloc call.
+      if (const ConstantInt* C = dyn_cast<ConstantInt>(CI->getOperand(1)))
+        return (C->getZExtValue() < Size);
+    return false;
   } else if (const Argument *A = dyn_cast<Argument>(V)) {
     if (A->hasByValAttr())
       AccessTy = cast<PointerType>(A->getType())->getElementType();
@@ -340,9 +347,10 @@ BasicAliasAnalysis::alias(const Value *V1, unsigned V1Size,
   
   // If the size of one access is larger than the entire object on the other
   // side, then we know such behavior is undefined and can assume no alias.
+  LLVMContext &Context = V1->getContext();
   if (TD)
-    if ((V1Size != ~0U && isObjectSmallerThan(O2, V1Size, *TD)) ||
-        (V2Size != ~0U && isObjectSmallerThan(O1, V2Size, *TD)))
+    if ((V1Size != ~0U && isObjectSmallerThan(O2, V1Size, Context, *TD)) ||
+        (V2Size != ~0U && isObjectSmallerThan(O1, V2Size, Context, *TD)))
       return NoAlias;
   
   // If one pointer is the result of a call/invoke and the other is a

lib/Analysis/IPA/Andersens.cpp

@@ -64,6 +64,7 @@
 #include "llvm/Support/InstIterator.h"
 #include "llvm/Support/InstVisitor.h"
 #include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/MallocHelper.h"
 #include "llvm/Analysis/Passes.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/System/Atomic.h"
@@ -592,9 +593,12 @@ namespace {
     friend class InstVisitor<Andersens>;
     void visitReturnInst(ReturnInst &RI);
     void visitInvokeInst(InvokeInst &II) { visitCallSite(CallSite(&II)); }
-    void visitCallInst(CallInst &CI) { visitCallSite(CallSite(&CI)); }
+    void visitCallInst(CallInst &CI) { 
+      if (isMalloc(&CI)) visitAllocationInst(CI);
+      else visitCallSite(CallSite(&CI)); 
+    }
     void visitCallSite(CallSite CS);
-    void visitAllocationInst(AllocationInst &AI);
+    void visitAllocationInst(Instruction &I);
     void visitLoadInst(LoadInst &LI);
     void visitStoreInst(StoreInst &SI);
     void visitGetElementPtrInst(GetElementPtrInst &GEP);
@@ -790,6 +794,8 @@ void Andersens::IdentifyObjects(Module &M) {
         ValueNodes[&*II] = NumObjects++;
         if (AllocationInst *AI = dyn_cast<AllocationInst>(&*II))
           ObjectNodes[AI] = NumObjects++;
+        else if (isMalloc(&*II))
+          ObjectNodes[&*II] = NumObjects++;
       }
 
       // Calls to inline asm need to be added as well because the callee isn't
@@ -1161,10 +1167,10 @@ void Andersens::visitInstruction(Instruction &I) {
   }
 }
 
-void Andersens::visitAllocationInst(AllocationInst &AI) {
-  unsigned ObjectIndex = getObject(&AI);
-  GraphNodes[ObjectIndex].setValue(&AI);
-  Constraints.push_back(Constraint(Constraint::AddressOf, getNodeValue(AI),
+void Andersens::visitAllocationInst(Instruction &I) {
+  unsigned ObjectIndex = getObject(&I);
+  GraphNodes[ObjectIndex].setValue(&I);
+  Constraints.push_back(Constraint(Constraint::AddressOf, getNodeValue(I),
                                    ObjectIndex));
 }
 
@@ -2813,7 +2819,7 @@ void Andersens::PrintNode(const Node *N) const {
   else
     errs() << "(unnamed)";
 
-  if (isa<GlobalValue>(V) || isa<AllocationInst>(V))
+  if (isa<GlobalValue>(V) || isa<AllocationInst>(V) || isMalloc(V))
     if (N == &GraphNodes[getObject(V)])
       errs() << "<mem>";
 }

lib/Analysis/IPA/GlobalsModRef.cpp

@@ -23,6 +23,7 @@
 #include "llvm/DerivedTypes.h"
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Analysis/CallGraph.h"
+#include "llvm/Analysis/MallocHelper.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/InstIterator.h"
@@ -236,6 +237,9 @@ bool GlobalsModRef::AnalyzeUsesOfPointer(Value *V,
       }
     } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(*UI)) {
       if (AnalyzeUsesOfPointer(GEP, Readers, Writers)) return true;
+    } else if (BitCastInst *BCI = dyn_cast<BitCastInst>(*UI)) {
+      if (AnalyzeUsesOfPointer(BCI, Readers, Writers, OkayStoreDest))
+        return true;
     } else if (CallInst *CI = dyn_cast<CallInst>(*UI)) {
       // Make sure that this is just the function being called, not that it is
       // passing into the function.
@@ -299,7 +303,7 @@ bool GlobalsModRef::AnalyzeIndirectGlobalMemory(GlobalValue *GV) {
       // Check the value being stored.
       Value *Ptr = SI->getOperand(0)->getUnderlyingObject();
 
-      if (isa<MallocInst>(Ptr)) {
+      if (isa<MallocInst>(Ptr) || isMalloc(Ptr)) {
         // Okay, easy case.
       } else if (CallInst *CI = dyn_cast<CallInst>(Ptr)) {
         Function *F = CI->getCalledFunction();
@@ -435,7 +439,8 @@ void GlobalsModRef::AnalyzeCallGraph(CallGraph &CG, Module &M) {
           if (cast<StoreInst>(*II).isVolatile())
             // Treat volatile stores as reading memory somewhere.
             FunctionEffect |= Ref;
-        } else if (isa<MallocInst>(*II) || isa<FreeInst>(*II)) {
+        } else if (isa<MallocInst>(*II) || isa<FreeInst>(*II) ||
+                   isMalloc(&cast<Instruction>(*II))) {
           FunctionEffect |= ModRef;
         }
 

lib/Analysis/MemoryDependenceAnalysis.cpp

@@ -20,6 +20,7 @@
 #include "llvm/IntrinsicInst.h"
 #include "llvm/Function.h"
 #include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/MallocHelper.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/PredIteratorCache.h"
@@ -233,6 +234,15 @@ getPointerDependencyFrom(Value *MemPtr, uint64_t MemSize, bool isLoad,
       continue;
     }
     
+    if (isMalloc(Inst)) {
+      Value *AccessPtr = MemPtr->getUnderlyingObject();
+      
+      if (AccessPtr == Inst ||
+          AA->alias(Inst, 1, AccessPtr, 1) == AliasAnalysis::MustAlias)
+        return MemDepResult::getDef(Inst);
+      continue;
+    }
+
     // See if this instruction (e.g. a call or vaarg) mod/ref's the pointer.
     switch (AA->getModRefInfo(Inst, MemPtr, MemSize)) {
     case AliasAnalysis::NoModRef:

lib/Analysis/PointerTracking.cpp

@@ -13,6 +13,7 @@
 #include "llvm/Analysis/ConstantFolding.h"
 #include "llvm/Analysis/Dominators.h"
 #include "llvm/Analysis/LoopInfo.h"
+#include "llvm/Analysis/MallocHelper.h"
 #include "llvm/Analysis/PointerTracking.h"
 #include "llvm/Analysis/ScalarEvolution.h"
 #include "llvm/Analysis/ScalarEvolutionExpressions.h"
@@ -99,6 +100,14 @@ const SCEV *PointerTracking::computeAllocationCount(Value *P,
     return SE->getSCEV(arraySize);
   }
 
+  if (CallInst *CI = extractMallocCall(V)) {
+    Value *arraySize = getMallocArraySize(CI, P->getContext(), TD);
+    Ty = getMallocAllocatedType(CI);
+    if (!Ty || !arraySize) return SE->getCouldNotCompute();
+    // arraySize elements of type Ty.
+    return SE->getSCEV(arraySize);
+  }
+
   if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V)) {
     if (GV->hasDefinitiveInitializer()) {
       Constant *C = GV->getInitializer();