X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FAliasAnalysis.cpp;h=c5523ec4634d8e4a83aa33d4afcbb1cf91acf18a;hb=6b38e29f13cb8700146e4b170567e2828553db9a;hp=c8c43a69ef743bb841505fa9e825da66c490498d;hpb=5a56bf631eef695b04bbd306b53d6094f7616b5e;p=oota-llvm.git

diff --git a/lib/Analysis/AliasAnalysis.cpp b/lib/Analysis/AliasAnalysis.cpp
index c8c43a69ef7..c5523ec4634 100644
--- a/lib/Analysis/AliasAnalysis.cpp
+++ b/lib/Analysis/AliasAnalysis.cpp
@@ -28,6 +28,7 @@
 #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"
@@ -58,13 +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();
@@ -117,9 +111,7 @@ AliasAnalysis::getModRefBehavior(CallSite CS,
   if (CS.doesNotAccessMemory())
     // Can't do better than this.
     return DoesNotAccessMemory;
-  ModRefBehavior MRB = UnknownModRefBehavior;
-  if (Function *F = CS.getCalledFunction())
-    MRB = getModRefBehavior(F, CS, Info);
+  ModRefBehavior MRB = getModRefBehavior(CS.getCalledFunction(), Info);
   if (MRB != DoesNotAccessMemory && CS.onlyReadsMemory())
     return OnlyReadsMemory;
   return MRB;
@@ -128,23 +120,41 @@ AliasAnalysis::getModRefBehavior(CallSite CS,
 AliasAnalysis::ModRefBehavior
 AliasAnalysis::getModRefBehavior(Function *F,
                                  std::vector<PointerAccessInfo> *Info) {
-  if (F->doesNotAccessMemory())
-    // Can't do better than this.
-    return DoesNotAccessMemory;
-  ModRefBehavior MRB = getModRefBehavior(F, CallSite(), Info);
-  if (MRB != DoesNotAccessMemory && F->onlyReadsMemory())
-    return OnlyReadsMemory;
-  return MRB;
+  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;
   ModRefBehavior MRB = getModRefBehavior(CS);
-  if (MRB == OnlyReadsMemory)
-    Mask = Ref;
-  else if (MRB == DoesNotAccessMemory)
+  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;
+  }
 
   if (!AA) return Mask;
 
@@ -207,6 +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