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

3 files changed, 58 insertions, 183 deletions

diff --git a/lib/Analysis/AliasAnalysis.cpp b/lib/Analysis/AliasAnalysis.cpp
index d9fe2f7407..503fbbdab8 100644
--- a/lib/Analysis/AliasAnalysis.cpp
+++ b/lib/Analysis/AliasAnalysis.cpp
@@ -229,20 +229,18 @@ bool llvm::isNoAliasCall(const Value *V) {
 /// identifiable object.  This returns true for:
 ///    Global Variables and Functions (but not Global Aliases)
 ///    Allocas and Mallocs
-///    ByVal and NoAlias Arguments, if Interprocedural is false
-///    NoAlias returns, if Interprocedural is false
+///    ByVal and NoAlias Arguments
+///    NoAlias returns
 ///
-bool llvm::isIdentifiedObject(const Value *V, bool Interprocedural) {
+bool llvm::isIdentifiedObject(const Value *V) {
   if (isa<AllocaInst>(V))
     return true;
   if (isa<GlobalValue>(V) && !isa<GlobalAlias>(V))
     return true;
-  if (!Interprocedural) {
-    if (isNoAliasCall(V))
-      return true;
-    if (const Argument *A = dyn_cast<Argument>(V))
-      return A->hasNoAliasAttr() || A->hasByValAttr();
-  }
+  if (isNoAliasCall(V))
+    return true;
+  if (const Argument *A = dyn_cast<Argument>(V))
+    return A->hasNoAliasAttr() || A->hasByValAttr();
   return false;
 }
 
diff --git a/lib/Analysis/AliasAnalysisEvaluator.cpp b/lib/Analysis/AliasAnalysisEvaluator.cpp
index d4ebdf3465..37ee9fc22c 100644
--- a/lib/Analysis/AliasAnalysisEvaluator.cpp
+++ b/lib/Analysis/AliasAnalysisEvaluator.cpp
@@ -21,7 +21,6 @@
 #include "llvm/DerivedTypes.h"
 #include "llvm/Function.h"
 #include "llvm/Instructions.h"
-#include "llvm/Module.h"
 #include "llvm/Pass.h"
 #include "llvm/Analysis/Passes.h"
 #include "llvm/Analysis/AliasAnalysis.h"
@@ -45,21 +44,20 @@ static cl::opt<bool> PrintRef("print-ref", cl::ReallyHidden);
 static cl::opt<bool> PrintModRef("print-modref", cl::ReallyHidden);
 
 namespace {
-  /// AAEval - Base class for exhaustive alias analysis evaluators.
-  class AAEval {
-  protected:
+  class AAEval : public FunctionPass {
     unsigned NoAlias, MayAlias, MustAlias;
     unsigned NoModRef, Mod, Ref, ModRef;
 
-    SetVector<Value *> Pointers;
-    SetVector<CallSite> CallSites;
+  public:
+    static char ID; // Pass identification, replacement for typeid
+    AAEval() : FunctionPass(&ID) {}
 
-    void getAnalysisUsage(AnalysisUsage &AU) const {
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
       AU.addRequired<AliasAnalysis>();
       AU.setPreservesAll();
     }
 
-    void doInitialization(Module &M) {
+    bool doInitialization(Module &M) {
       NoAlias = MayAlias = MustAlias = 0;
       NoModRef = Mod = Ref = ModRef = 0;
 
@@ -67,85 +65,19 @@ namespace {
         PrintNoAlias = PrintMayAlias = PrintMustAlias = true;
         PrintNoModRef = PrintMod = PrintRef = PrintModRef = true;
       }
-    }
-
-    void runOnFunction(Function &F);
-    void evaluate(AliasAnalysis *AA, Module *M);
-    void doFinalization(Module &M);
-  };
-
-  class FunctionAAEval : public FunctionPass, AAEval {
-  public:
-    static char ID; // Pass identification, replacement for typeid
-    FunctionAAEval() : FunctionPass(&ID) {}
-
-    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
-      return AAEval::getAnalysisUsage(AU);
-    }
-
-    virtual bool doInitialization(Module &M) {
-      AAEval::doInitialization(M);
-      return false;
-    }
-
-    virtual bool runOnFunction(Function &F) {
-      AAEval::runOnFunction(F);
-
-      if (PrintNoAlias || PrintMayAlias || PrintMustAlias ||
-          PrintNoModRef || PrintMod || PrintRef || PrintModRef)
-        errs() << "Function: " << F.getName() << ": " << Pointers.size()
-               << " pointers, " << CallSites.size() << " call sites\n";
-
-      AAEval::evaluate(&getAnalysis<AliasAnalysis>(), F.getParent());
       return false;
     }
 
-    virtual bool doFinalization(Module &M) {
-      AAEval::doFinalization(M);
-      return false;
-    }
-  };
-
-  class InterproceduralAAEval : public ModulePass, AAEval {
-  public:
-    static char ID; // Pass identification, replacement for typeid
-    InterproceduralAAEval() : ModulePass(&ID) {}
-
-    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
-      return AAEval::getAnalysisUsage(AU);
-    }
-
-    virtual bool runOnModule(Module &M) {
-      AAEval::doInitialization(M);
-      for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
-        AAEval::runOnFunction(*I);
-
-      if (PrintNoAlias || PrintMayAlias || PrintMustAlias ||
-          PrintNoModRef || PrintMod || PrintRef || PrintModRef)
-        errs() << "Module: " << Pointers.size()
-               << " pointers, " << CallSites.size() << " call sites\n";
-
-      AAEval::evaluate(&getAnalysis<AliasAnalysis>(), &M);
-      AAEval::doFinalization(M);
-      return false;
-    }
+    bool runOnFunction(Function &F);
+    bool doFinalization(Module &M);
   };
 }
 
-char FunctionAAEval::ID = 0;
-static RegisterPass<FunctionAAEval>
+char AAEval::ID = 0;
+static RegisterPass<AAEval>
 X("aa-eval", "Exhaustive Alias Analysis Precision Evaluator", false, true);
 
-FunctionPass *llvm::createAAEvalPass() { return new FunctionAAEval(); }
-
-char InterproceduralAAEval::ID = 0;
-static RegisterPass<InterproceduralAAEval>
-Y("interprocedural-aa-eval",
-  "Exhaustive Interprocedural Alias Analysis Precision Evaluator", false, true);
-
-Pass *llvm::createInterproceduralAAEvalPass() {
-  return new InterproceduralAAEval();
-}
+FunctionPass *llvm::createAAEvalPass() { return new AAEval(); }
 
 static void PrintResults(const char *Msg, bool P, const Value *V1,
                          const Value *V2, const Module *M) {
@@ -180,7 +112,12 @@ static inline bool isInterestingPointer(Value *V) {
       && !isa<ConstantPointerNull>(V);
 }
 
-void AAEval::runOnFunction(Function &F) {
+bool AAEval::runOnFunction(Function &F) {
+  AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
+
+  SetVector<Value *> Pointers;
+  SetVector<CallSite> CallSites;
+
   for (Function::arg_iterator I = F.arg_begin(), E = F.arg_end(); I != E; ++I)
     if (I->getType()->isPointerTy())    // Add all pointer arguments.
       Pointers.insert(I);
@@ -210,31 +147,33 @@ void AAEval::runOnFunction(Function &F) {
 
     if (CS.getInstruction()) CallSites.insert(CS);
   }
-}
 
-void AAEval::evaluate(AliasAnalysis *AA, Module *M) {
+  if (PrintNoAlias || PrintMayAlias || PrintMustAlias ||
+      PrintNoModRef || PrintMod || PrintRef || PrintModRef)
+    errs() << "Function: " << F.getName() << ": " << Pointers.size()
+           << " pointers, " << CallSites.size() << " call sites\n";
 
   // iterate over the worklist, and run the full (n^2)/2 disambiguations
   for (SetVector<Value *>::iterator I1 = Pointers.begin(), E = Pointers.end();
        I1 != E; ++I1) {
     unsigned I1Size = ~0u;
     const Type *I1ElTy = cast<PointerType>((*I1)->getType())->getElementType();
-    if (I1ElTy->isSized()) I1Size = AA->getTypeStoreSize(I1ElTy);
+    if (I1ElTy->isSized()) I1Size = AA.getTypeStoreSize(I1ElTy);
 
     for (SetVector<Value *>::iterator I2 = Pointers.begin(); I2 != I1; ++I2) {
       unsigned I2Size = ~0u;
       const Type *I2ElTy =cast<PointerType>((*I2)->getType())->getElementType();
-      if (I2ElTy->isSized()) I2Size = AA->getTypeStoreSize(I2ElTy);
+      if (I2ElTy->isSized()) I2Size = AA.getTypeStoreSize(I2ElTy);
 
-      switch (AA->alias(*I1, I1Size, *I2, I2Size)) {
+      switch (AA.alias(*I1, I1Size, *I2, I2Size)) {
       case AliasAnalysis::NoAlias:
-        PrintResults("NoAlias", PrintNoAlias, *I1, *I2, M);
+        PrintResults("NoAlias", PrintNoAlias, *I1, *I2, F.getParent());
         ++NoAlias; break;
       case AliasAnalysis::MayAlias:
-        PrintResults("MayAlias", PrintMayAlias, *I1, *I2, M);
+        PrintResults("MayAlias", PrintMayAlias, *I1, *I2, F.getParent());
         ++MayAlias; break;
       case AliasAnalysis::MustAlias:
-        PrintResults("MustAlias", PrintMustAlias, *I1, *I2, M);
+        PrintResults("MustAlias", PrintMustAlias, *I1, *I2, F.getParent());
         ++MustAlias; break;
       default:
         errs() << "Unknown alias query result!\n";
@@ -251,20 +190,20 @@ void AAEval::evaluate(AliasAnalysis *AA, Module *M) {
          V != Ve; ++V) {
       unsigned Size = ~0u;
       const Type *ElTy = cast<PointerType>((*V)->getType())->getElementType();
-      if (ElTy->isSized()) Size = AA->getTypeStoreSize(ElTy);
+      if (ElTy->isSized()) Size = AA.getTypeStoreSize(ElTy);
 
-      switch (AA->getModRefInfo(*C, *V, Size)) {
+      switch (AA.getModRefInfo(*C, *V, Size)) {
       case AliasAnalysis::NoModRef:
-        PrintModRefResults("NoModRef", PrintNoModRef, I, *V, M);
+        PrintModRefResults("NoModRef", PrintNoModRef, I, *V, F.getParent());
         ++NoModRef; break;
       case AliasAnalysis::Mod:
-        PrintModRefResults("     Mod", PrintMod, I, *V, M);
+        PrintModRefResults("     Mod", PrintMod, I, *V, F.getParent());
         ++Mod; break;
       case AliasAnalysis::Ref:
-        PrintModRefResults("     Ref", PrintRef, I, *V, M);
+        PrintModRefResults("     Ref", PrintRef, I, *V, F.getParent());
         ++Ref; break;
       case AliasAnalysis::ModRef:
-        PrintModRefResults("  ModRef", PrintModRef, I, *V, M);
+        PrintModRefResults("  ModRef", PrintModRef, I, *V, F.getParent());
         ++ModRef; break;
       default:
         errs() << "Unknown alias query result!\n";
@@ -272,8 +211,7 @@ void AAEval::evaluate(AliasAnalysis *AA, Module *M) {
     }
   }
 
-  Pointers.clear();
-  CallSites.clear();
+  return false;
 }
 
 static void PrintPercent(unsigned Num, unsigned Sum) {
@@ -281,7 +219,7 @@ static void PrintPercent(unsigned Num, unsigned Sum) {
          << ((Num*1000ULL/Sum) % 10) << "%)\n";
 }
 
-void AAEval::doFinalization(Module &M) {
+bool AAEval::doFinalization(Module &M) {
   unsigned AliasSum = NoAlias + MayAlias + MustAlias;
   errs() << "===== Alias Analysis Evaluator Report =====\n";
   if (AliasSum == 0) {
@@ -317,4 +255,6 @@ void AAEval::doFinalization(Module &M) {
            << NoModRef*100/ModRefSum  << "%/" << Mod*100/ModRefSum << "%/"
            << Ref*100/ModRefSum << "%/" << ModRef*100/ModRefSum << "%\n";
   }
+
+  return false;
 }
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();
-}