Remove interprocedural-basic-aa and associated code. The AliasAnalysis

interface needs implementations to be consistent, so any code which
wants to support different semantics must use a different interface.
It's not currently worthwhile to add a new interface for this new
concept.

Document that AliasAnalysis doesn't support cross-function queries.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107776 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 14 insertions, 77 deletions

diff --git a/lib/Analysis/BasicAliasAnalysis.cpp b/lib/Analysis/BasicAliasAnalysis.cpp
index 2f99c2e6b6..d3a67a8eba 100644
--- a/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/lib/Analysis/BasicAliasAnalysis.cpp
@@ -194,6 +194,7 @@ ImmutablePass *llvm::createNoAAPass() { return new NoAA(); }
 // BasicAliasAnalysis Pass
 //===----------------------------------------------------------------------===//
 
+#ifndef NDEBUG
 static const Function *getParent(const Value *V) {
   if (const Instruction *inst = dyn_cast<Instruction>(V))
     return inst->getParent()->getParent();
@@ -204,15 +205,6 @@ static const Function *getParent(const Value *V) {
   return NULL;
 }
 
-static bool sameParent(const Value *O1, const Value *O2) {
-
-  const Function *F1 = getParent(O1);
-  const Function *F2 = getParent(O2);
-
-  return F1 && F1 == F2;
-}
-
-#ifdef XDEBUG
 static bool notDifferentParent(const Value *O1, const Value *O2) {
 
   const Function *F1 = getParent(O1);
@@ -227,25 +219,14 @@ namespace {
   /// Because it doesn't chain to a previous alias analysis (like -no-aa), it
   /// derives from the NoAA class.
   struct BasicAliasAnalysis : public NoAA {
-    /// Interprocedural - Flag for "interprocedural" mode, where we must
-    /// support queries of values which live in different functions.
-    bool Interprocedural;
-
     static char ID; // Class identification, replacement for typeinfo
-    BasicAliasAnalysis()
-      : NoAA(&ID), Interprocedural(false) {}
-    BasicAliasAnalysis(void *PID, bool interprocedural)
-      : NoAA(PID), Interprocedural(interprocedural) {}
+    BasicAliasAnalysis() : NoAA(&ID) {}
 
     AliasResult alias(const Value *V1, unsigned V1Size,
                       const Value *V2, unsigned V2Size) {
       assert(Visited.empty() && "Visited must be cleared after use!");
-#ifdef XDEBUG
-      assert((Interprocedural || notDifferentParent(V1, V2)) &&
-             "BasicAliasAnalysis (-basicaa) doesn't support interprocedural "
-             "queries; use InterproceduralAliasAnalysis "
-             "(-interprocedural-basic-aa) instead.");
-#endif
+      assert(notDifferentParent(V1, V2) &&
+             "BasicAliasAnalysis doesn't support interprocedural queries.");
       AliasResult Alias = aliasCheck(V1, V1Size, V2, V2Size);
       Visited.clear();
       return Alias;
@@ -324,6 +305,9 @@ bool BasicAliasAnalysis::pointsToConstantMemory(const Value *P) {
 /// simple "address taken" analysis on local objects.
 AliasAnalysis::ModRefResult
 BasicAliasAnalysis::getModRefInfo(CallSite CS, Value *P, unsigned Size) {
+  assert(notDifferentParent(CS.getInstruction(), P) &&
+         "AliasAnalysis query involving multiple functions!");
+
   const Value *Object = P->getUnderlyingObject();
   
   // If this is a tail call and P points to a stack location, we know that
@@ -336,16 +320,10 @@ BasicAliasAnalysis::getModRefInfo(CallSite CS, Value *P, unsigned Size) {
       if (CI->isTailCall())
         return NoModRef;
   
-  // If we can identify an object and it's known to be within the
-  // same function as the call, we can ignore interprocedural concerns.
-  bool EffectivelyInterprocedural =
-    Interprocedural && !sameParent(Object, CS.getInstruction());
-  
   // If the pointer is to a locally allocated object that does not escape,
   // then the call can not mod/ref the pointer unless the call takes the pointer
   // as an argument, and itself doesn't capture it.
   if (!isa<Constant>(Object) && CS.getInstruction() != Object &&
-      !EffectivelyInterprocedural &&
       isNonEscapingLocalObject(Object)) {
     bool PassedAsArg = false;
     unsigned ArgNo = 0;
@@ -765,36 +743,25 @@ BasicAliasAnalysis::aliasCheck(const Value *V1, unsigned V1Size,
     if (CPN->getType()->getAddressSpace() == 0)
       return NoAlias;
 
-  // If we can identify two objects and they're known to be within the
-  // same function, we can ignore interprocedural concerns.
-  bool EffectivelyInterprocedural =
-    Interprocedural && !sameParent(O1, O2);
-
   if (O1 != O2) {
     // If V1/V2 point to two different objects we know that we have no alias.
-    if (isIdentifiedObject(O1, EffectivelyInterprocedural) &&
-        isIdentifiedObject(O2, EffectivelyInterprocedural))
+    if (isIdentifiedObject(O1) && isIdentifiedObject(O2))
       return NoAlias;
 
     // Constant pointers can't alias with non-const isIdentifiedObject objects.
-    if ((isa<Constant>(O1) &&
-         isIdentifiedObject(O2, EffectivelyInterprocedural) &&
-         !isa<Constant>(O2)) ||
-        (isa<Constant>(O2) &&
-         isIdentifiedObject(O1, EffectivelyInterprocedural) &&
-         !isa<Constant>(O1)))
+    if ((isa<Constant>(O1) && isIdentifiedObject(O2) && !isa<Constant>(O2)) ||
+        (isa<Constant>(O2) && isIdentifiedObject(O1) && !isa<Constant>(O1)))
       return NoAlias;
 
     // Arguments can't alias with local allocations or noalias calls
     // in the same function.
-    if (!EffectivelyInterprocedural &&
-        ((isa<Argument>(O1) && (isa<AllocaInst>(O2) || isNoAliasCall(O2))) ||
+    if (((isa<Argument>(O1) && (isa<AllocaInst>(O2) || isNoAliasCall(O2))) ||
          (isa<Argument>(O2) && (isa<AllocaInst>(O1) || isNoAliasCall(O1)))))
       return NoAlias;
 
     // Most objects can't alias null.
-    if ((isa<ConstantPointerNull>(V2) && isKnownNonNull(O1)) ||
-        (isa<ConstantPointerNull>(V1) && isKnownNonNull(O2)))
+    if ((isa<ConstantPointerNull>(O2) && isKnownNonNull(O1)) ||
+        (isa<ConstantPointerNull>(O1) && isKnownNonNull(O2)))
       return NoAlias;
   }
   
@@ -814,7 +781,7 @@ BasicAliasAnalysis::aliasCheck(const Value *V1, unsigned V1Size,
   // temporary store the nocapture argument's value in a temporary memory
   // location if that memory location doesn't escape. Or it may pass a
   // nocapture value to other functions as long as they don't capture it.
-  if (O1 != O2 && !EffectivelyInterprocedural) {
+  if (O1 != O2) {
     if (isEscapeSource(O1) && isNonEscapingLocalObject(O2))
       return NoAlias;
     if (isEscapeSource(O2) && isNonEscapingLocalObject(O1))
@@ -850,33 +817,3 @@ BasicAliasAnalysis::aliasCheck(const Value *V1, unsigned V1Size,
 
 // Make sure that anything that uses AliasAnalysis pulls in this file.
 DEFINING_FILE_FOR(BasicAliasAnalysis)
-
-//===----------------------------------------------------------------------===//
-// InterproceduralBasicAliasAnalysis Pass
-//===----------------------------------------------------------------------===//
-
-namespace {
-  /// InterproceduralBasicAliasAnalysis - This is similar to basicaa, except
-  /// that it properly supports queries to values which live in different
-  /// functions.
-  ///
-  /// Note that we don't currently take this to the extreme, analyzing all
-  /// call sites of a function to answer a query about an Argument.
-  ///
-  struct InterproceduralBasicAliasAnalysis : public BasicAliasAnalysis {
-    static char ID; // Class identification, replacement for typeinfo
-    InterproceduralBasicAliasAnalysis() : BasicAliasAnalysis(&ID, true) {}
-  };
-}
-
-// Register this pass...
-char InterproceduralBasicAliasAnalysis::ID = 0;
-static RegisterPass<InterproceduralBasicAliasAnalysis>
-W("interprocedural-basic-aa", "Interprocedural Basic Alias Analysis", false, true);
-
-// Declare that we implement the AliasAnalysis interface
-static RegisterAnalysisGroup<AliasAnalysis> Z(W);
-
-ImmutablePass *llvm::createInterproceduralBasicAliasAnalysisPass() {
-  return new InterproceduralBasicAliasAnalysis();
-}