Integrate the readonly/readnone logic more deeply

into alias analysis.  This meant updating the API
which now has versions of the getModRefBehavior,
doesNotAccessMemory and onlyReadsMemory methods
which take a callsite parameter.  These should be
used unless the callsite is not known, since in
general they can do a better job than the versions
that take a function.  Also, users should no longer
call the version of getModRefBehavior that takes
both a function and a callsite.  To reduce the
chance of misuse it is now protected.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44487 91177308-0d34-0410-b5e6-96231b3b80d8

7 files changed, 58 insertions, 43 deletions

diff --git a/lib/Analysis/AliasAnalysis.cpp b/lib/Analysis/AliasAnalysis.cpp
index 2a3ac5a..9e1ae2a 100644
--- a/lib/Analysis/AliasAnalysis.cpp
+++ b/lib/Analysis/AliasAnalysis.cpp
@@ -27,6 +27,7 @@
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Pass.h"
 #include "llvm/BasicBlock.h"
+#include "llvm/Function.h"
 #include "llvm/Instructions.h"
 #include "llvm/Type.h"
 #include "llvm/Target/TargetData.h"
@@ -112,16 +113,40 @@ 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.paramHasAttr(0, ParamAttr::ReadNone))
+    // Can't do better than this.
+    return DoesNotAccessMemory;
+  ModRefBehavior MRB = UnknownModRefBehavior;
+  if (Function *F = CS.getCalledFunction())
+    MRB = getModRefBehavior(F, CS, Info);
+  if (MRB != DoesNotAccessMemory && CS.paramHasAttr(0, ParamAttr::ReadOnly))
+    return OnlyReadsMemory;
+  return MRB;
+}
+
+AliasAnalysis::ModRefBehavior
+AliasAnalysis::getModRefBehavior(Function *F,
+                                 std::vector<PointerAccessInfo> *Info) {
+  if (F->paramHasAttr(0, ParamAttr::ReadNone))
+    // Can't do better than this.
+    return DoesNotAccessMemory;
+  ModRefBehavior MRB = getModRefBehavior(F, CallSite(), Info);
+  if (MRB != DoesNotAccessMemory && F->paramHasAttr(0, ParamAttr::ReadOnly))
+    return OnlyReadsMemory;
+  return MRB;
+}
+
 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)
-      return NoModRef;
-  }
+  ModRefBehavior MRB = getModRefBehavior(CS);
+  if (MRB == OnlyReadsMemory)
+    Mask = Ref;
+  else if (MRB == DoesNotAccessMemory)
+    return NoModRef;
 
   if (!AA) return Mask;
 
diff --git a/lib/Analysis/AliasAnalysisCounter.cpp b/lib/Analysis/AliasAnalysisCounter.cpp
index eea2c99..2fccff1 100644
--- a/lib/Analysis/AliasAnalysisCounter.cpp
+++ b/lib/Analysis/AliasAnalysisCounter.cpp
@@ -89,9 +89,15 @@ namespace {
     bool pointsToConstantMemory(const Value *P) {
       return getAnalysis<AliasAnalysis>().pointsToConstantMemory(P);
     }
+    bool doesNotAccessMemory(CallSite CS) {
+      return getAnalysis<AliasAnalysis>().doesNotAccessMemory(CS);
+    }
     bool doesNotAccessMemory(Function *F) {
       return getAnalysis<AliasAnalysis>().doesNotAccessMemory(F);
     }
+    bool onlyReadsMemory(CallSite CS) {
+      return getAnalysis<AliasAnalysis>().onlyReadsMemory(CS);
+    }
     bool onlyReadsMemory(Function *F) {
       return getAnalysis<AliasAnalysis>().onlyReadsMemory(F);
     }
diff --git a/lib/Analysis/AliasSetTracker.cpp b/lib/Analysis/AliasSetTracker.cpp
index fcdd1b3..1b20c7a 100644
--- a/lib/Analysis/AliasSetTracker.cpp
+++ b/lib/Analysis/AliasSetTracker.cpp
@@ -114,15 +114,13 @@ void AliasSet::addPointer(AliasSetTracker &AST, HashNodePair &Entry,
 void AliasSet::addCallSite(CallSite CS, AliasAnalysis &AA) {
   CallSites.push_back(CS);
 
-  if (Function *F = CS.getCalledFunction()) {
-    AliasAnalysis::ModRefBehavior Behavior = AA.getModRefBehavior(F, CS);
-    if (Behavior == AliasAnalysis::DoesNotAccessMemory)
-      return;
-    else if (Behavior == AliasAnalysis::OnlyReadsMemory) {
-      AliasTy = MayAlias;
-      AccessTy |= Refs;
-      return;
-    }
+  AliasAnalysis::ModRefBehavior Behavior = AA.getModRefBehavior(CS);
+  if (Behavior == AliasAnalysis::DoesNotAccessMemory)
+    return;
+  else if (Behavior == AliasAnalysis::OnlyReadsMemory) {
+    AliasTy = MayAlias;
+    AccessTy |= Refs;
+    return;
   }
 
   // FIXME: This should use mod/ref information to make this not suck so bad
@@ -166,9 +164,8 @@ bool AliasSet::aliasesPointer(const Value *Ptr, unsigned Size,
 }
 
 bool AliasSet::aliasesCallSite(CallSite CS, AliasAnalysis &AA) const {
-  if (Function *F = CS.getCalledFunction())
-    if (AA.doesNotAccessMemory(F))
-      return false;
+  if (AA.doesNotAccessMemory(CS))
+    return false;
 
   if (AA.hasNoModRefInfoForCalls())
     return true;
@@ -297,9 +294,8 @@ bool AliasSetTracker::add(FreeInst *FI) {
 
 
 bool AliasSetTracker::add(CallSite CS) {
-  if (Function *F = CS.getCalledFunction())
-    if (AA.doesNotAccessMemory(F))
-      return true; // doesn't alias anything
+  if (AA.doesNotAccessMemory(CS))
+    return true; // doesn't alias anything
 
   AliasSet *AS = findAliasSetForCallSite(CS);
   if (!AS) {
@@ -419,9 +415,8 @@ bool AliasSetTracker::remove(FreeInst *FI) {
 }
 
 bool AliasSetTracker::remove(CallSite CS) {
-  if (Function *F = CS.getCalledFunction())
-    if (AA.doesNotAccessMemory(F))
-      return false; // doesn't alias anything
+  if (AA.doesNotAccessMemory(CS))
+    return false; // doesn't alias anything
 
   AliasSet *AS = findAliasSetForCallSite(CS);
   if (!AS) return false;
@@ -455,13 +450,10 @@ void AliasSetTracker::deleteValue(Value *PtrVal) {
   // If this is a call instruction, remove the callsite from the appropriate
   // AliasSet.
   CallSite CS = CallSite::get(PtrVal);
-  if (CS.getInstruction()) {
-    Function *F = CS.getCalledFunction();
-    if (!F || !AA.doesNotAccessMemory(F)) {
+  if (CS.getInstruction())
+    if (!AA.doesNotAccessMemory(CS))
       if (AliasSet *AS = findAliasSetForCallSite(CS))
         AS->removeCallSite(CS);
-    }
-  }
 
   // First, look up the PointerRec for this pointer.
   hash_map<Value*, AliasSet::PointerRec>::iterator I = PointerMap.find(PtrVal);
diff --git a/lib/Analysis/BasicAliasAnalysis.cpp b/lib/Analysis/BasicAliasAnalysis.cpp
index 575e921..5ec9afa 100644
--- a/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/lib/Analysis/BasicAliasAnalysis.cpp
@@ -839,11 +839,6 @@ BasicAliasAnalysis::getModRefBehavior(Function *F, CallSite CS,
     return UnknownModRefBehavior;
   }
 
-  if (F->paramHasAttr(0, ParamAttr::ReadNone))
-    return DoesNotAccessMemory;
-  if (F->paramHasAttr(0, ParamAttr::ReadOnly))
-    return OnlyReadsMemory;
-
   return UnknownModRefBehavior;
 }
 
diff --git a/lib/Analysis/IPA/GlobalsModRef.cpp b/lib/Analysis/IPA/GlobalsModRef.cpp
index dce4a1e..9e943dd 100644
--- a/lib/Analysis/IPA/GlobalsModRef.cpp
+++ b/lib/Analysis/IPA/GlobalsModRef.cpp
@@ -394,7 +394,7 @@ void GlobalsModRef::AnalyzeSCC(std::vector<CallGraphNode *> &SCC) {
           // Okay, if we can't say anything about it, maybe some other alias
           // analysis can.
           ModRefBehavior MRB =
-            AliasAnalysis::getModRefBehavior(Callee, CallSite());
+            AliasAnalysis::getModRefBehavior(Callee);
           if (MRB != DoesNotAccessMemory) {
             // FIXME: could make this more aggressive for functions that just
             // read memory.  We should just say they read all globals.
diff --git a/lib/Analysis/LoadValueNumbering.cpp b/lib/Analysis/LoadValueNumbering.cpp
index 3af92bc..67d4dd22 100644
--- a/lib/Analysis/LoadValueNumbering.cpp
+++ b/lib/Analysis/LoadValueNumbering.cpp
@@ -148,7 +148,7 @@ void LoadVN::getCallEqualNumberNodes(CallInst *CI,
   Function *CF = CI->getCalledFunction();
   if (CF == 0) return;  // Indirect call.
   AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
-  AliasAnalysis::ModRefBehavior MRB = AA.getModRefBehavior(CF, CI);
+  AliasAnalysis::ModRefBehavior MRB = AA.getModRefBehavior(CI);
   if (MRB != AliasAnalysis::DoesNotAccessMemory &&
       MRB != AliasAnalysis::OnlyReadsMemory)
     return;  // Nothing we can do for now.
@@ -227,8 +227,7 @@ void LoadVN::getCallEqualNumberNodes(CallInst *CI,
               CantEqual = true;
               break;
             } else if (CallInst *CI = dyn_cast<CallInst>(I)) {
-              if (CI->getCalledFunction() == 0 ||
-                  !AA.onlyReadsMemory(CI->getCalledFunction())) {
+              if (!AA.onlyReadsMemory(CI)) {
                 CantEqual = true;
                 break;
               }
diff --git a/lib/Analysis/MemoryDependenceAnalysis.cpp b/lib/Analysis/MemoryDependenceAnalysis.cpp
index dd567aa..8c5f216 100644
--- a/lib/Analysis/MemoryDependenceAnalysis.cpp
+++ b/lib/Analysis/MemoryDependenceAnalysis.cpp
@@ -94,11 +94,9 @@ Instruction* MemoryDependenceAnalysis::getCallSiteDependency(CallSite C,
       
       // FreeInsts erase the entire structure
       pointerSize = ~0UL;
-    } else if (CallSite::get(QI).getInstruction() != 0 &&
-               cast<CallInst>(QI)->getCalledFunction()) {
+    } else if (isa<CallInst>(QI)) {
       AliasAnalysis::ModRefBehavior result =
-                   AA.getModRefBehavior(cast<CallInst>(QI)->getCalledFunction(),
-                                        CallSite::get(QI));
+                   AA.getModRefBehavior(CallSite::get(QI));
       if (result != AliasAnalysis::DoesNotAccessMemory &&
           result != AliasAnalysis::OnlyReadsMemory) {
         if (!start && !block) {