X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FAliasAnalysis.cpp;h=c5523ec4634d8e4a83aa33d4afcbb1cf91acf18a;hb=6b38e29f13cb8700146e4b170567e2828553db9a;hp=32d2bb6b363255ec656062f1b54f9becdff18df9;hpb=3e15bf33e024b9df9e89351a165acfdb1dde51ed;p=oota-llvm.git

diff --git a/lib/Analysis/AliasAnalysis.cpp b/lib/Analysis/AliasAnalysis.cpp
index 32d2bb6b363..c5523ec4634 100644
--- a/lib/Analysis/AliasAnalysis.cpp
+++ b/lib/Analysis/AliasAnalysis.cpp
@@ -2,8 +2,8 @@
 //
 //                     The LLVM Compiler Infrastructure
 //
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
@@ -27,16 +27,16 @@
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Pass.h"
 #include "llvm/BasicBlock.h"
+#include "llvm/Function.h"
+#include "llvm/IntrinsicInst.h"
 #include "llvm/Instructions.h"
 #include "llvm/Type.h"
 #include "llvm/Target/TargetData.h"
 using namespace llvm;
 
 // Register the AliasAnalysis interface, providing a nice name to refer to.
-namespace {
-  RegisterAnalysisGroup<AliasAnalysis> Z("Alias Analysis");
-}
-const char AliasAnalysis::ID = 0;
+static RegisterAnalysisGroup<AliasAnalysis> Z("Alias Analysis");
+char AliasAnalysis::ID = 0;
 
 //===----------------------------------------------------------------------===//
 // Default chaining methods
@@ -59,13 +59,6 @@ bool AliasAnalysis::pointsToConstantMemory(const Value *P) {
   return AA->pointsToConstantMemory(P);
 }
 
-AliasAnalysis::ModRefBehavior
-AliasAnalysis::getModRefBehavior(Function *F, CallSite CS,
-                                 std::vector<PointerAccessInfo> *Info) {
-  assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
-  return AA->getModRefBehavior(F, CS, Info);
-}
-
 bool AliasAnalysis::hasNoModRefInfoForCalls() const {
   assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
   return AA->hasNoModRefInfoForCalls();
@@ -95,7 +88,7 @@ AliasAnalysis::getModRefInfo(CallSite CS1, CallSite CS2) {
 
 AliasAnalysis::ModRefResult
 AliasAnalysis::getModRefInfo(LoadInst *L, Value *P, unsigned Size) {
-  return alias(L->getOperand(0), TD->getTypeSize(L->getType()),
+  return alias(L->getOperand(0), TD->getTypeStoreSize(L->getType()),
                P, Size) ? Ref : NoModRef;
 }
 
@@ -103,8 +96,8 @@ AliasAnalysis::ModRefResult
 AliasAnalysis::getModRefInfo(StoreInst *S, Value *P, unsigned Size) {
   // If the stored address cannot alias the pointer in question, then the
   // pointer cannot be modified by the store.
-  if (!alias(S->getOperand(1), TD->getTypeSize(S->getOperand(0)->getType()),
-             P, Size))
+  if (!alias(S->getOperand(1),
+             TD->getTypeStoreSize(S->getOperand(0)->getType()), P, Size))
     return NoModRef;
 
   // If the pointer is a pointer to constant memory, then it could not have been
@@ -112,14 +105,54 @@ AliasAnalysis::getModRefInfo(StoreInst *S, Value *P, unsigned Size) {
   return pointsToConstantMemory(P) ? NoModRef : Mod;
 }
 
+AliasAnalysis::ModRefBehavior
+AliasAnalysis::getModRefBehavior(CallSite CS,
+                                 std::vector<PointerAccessInfo> *Info) {
+  if (CS.doesNotAccessMemory())
+    // Can't do better than this.
+    return DoesNotAccessMemory;
+  ModRefBehavior MRB = getModRefBehavior(CS.getCalledFunction(), Info);
+  if (MRB != DoesNotAccessMemory && CS.onlyReadsMemory())
+    return OnlyReadsMemory;
+  return MRB;
+}
+
+AliasAnalysis::ModRefBehavior
+AliasAnalysis::getModRefBehavior(Function *F,
+                                 std::vector<PointerAccessInfo> *Info) {
+  if (F) {
+    if (F->doesNotAccessMemory())
+      // Can't do better than this.
+      return DoesNotAccessMemory;
+    if (F->onlyReadsMemory())
+      return OnlyReadsMemory;
+    if (unsigned id = F->getIntrinsicID()) {
+#define GET_INTRINSIC_MODREF_BEHAVIOR
+#include "llvm/Intrinsics.gen"
+#undef GET_INTRINSIC_MODREF_BEHAVIOR
+    }
+  }
+  return UnknownModRefBehavior;
+}
+
 AliasAnalysis::ModRefResult
 AliasAnalysis::getModRefInfo(CallSite CS, Value *P, unsigned Size) {
   ModRefResult Mask = ModRef;
-  if (Function *F = CS.getCalledFunction()) {
-    ModRefBehavior MRB = getModRefBehavior(F, CallSite());
-    if (MRB == OnlyReadsMemory)
-      Mask = Ref;
-    else if (MRB == DoesNotAccessMemory)
+  ModRefBehavior MRB = getModRefBehavior(CS);
+  if (MRB == DoesNotAccessMemory)
+    return NoModRef;
+  else if (MRB == OnlyReadsMemory)
+    Mask = Ref;
+  else if (MRB == AliasAnalysis::AccessesArguments) {
+    bool doesAlias = false;
+    for (CallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
+         AI != AE; ++AI)
+      if (alias(*AI, ~0U, P, Size) != NoAlias) {
+        doesAlias = true;
+        break;
+      }
+
+    if (!doesAlias)
       return NoModRef;
   }
 
@@ -140,7 +173,7 @@ AliasAnalysis::getModRefInfo(CallSite CS, Value *P, unsigned Size) {
 //
 AliasAnalysis::~AliasAnalysis() {}
 
-/// setTargetData - Subclasses must call this method to initialize the
+/// InitializeAliasAnalysis - Subclasses must call this method to initialize the
 /// AliasAnalysis interface before any other methods are called.
 ///
 void AliasAnalysis::InitializeAliasAnalysis(Pass *P) {
@@ -184,6 +217,30 @@ bool AliasAnalysis::canInstructionRangeModify(const Instruction &I1,
   return false;
 }
 
+/// isNoAliasCall - Return true if this pointer is returned by a noalias
+/// function.
+bool llvm::isNoAliasCall(const Value *V) {
+  if (isa<CallInst>(V) || isa<InvokeInst>(V))
+    return CallSite(const_cast<Instruction*>(cast<Instruction>(V)))
+      .paramHasAttr(0, Attribute::NoAlias);
+  return false;
+}
+
+/// isIdentifiedObject - Return true if this pointer refers to a distinct and
+/// identifiable object.  This returns true for:
+///    Global Variables and Functions
+///    Allocas and Mallocs
+///    ByVal and NoAlias Arguments
+///    NoAlias returns
+///
+bool llvm::isIdentifiedObject(const Value *V) {
+  if (isa<GlobalValue>(V) || isa<AllocationInst>(V) || isNoAliasCall(V))
+    return true;
+  if (const Argument *A = dyn_cast<Argument>(V))
+    return A->hasNoAliasAttr() || A->hasByValAttr();
+  return false;
+}
+
 // Because of the way .a files work, we must force the BasicAA implementation to
 // be pulled in if the AliasAnalysis classes are pulled in.  Otherwise we run
 // the risk of AliasAnalysis being used, but the default implementation not