Extend the AliasAnalysis::pointsToConstantMemory interface to allow it
to optionally look for constant or local (alloca) memory.
Teach BasicAliasAnalysis::pointsToConstantMemory to look through Select
and Phi nodes, and to support looking for local memory.
Remove FunctionAttrs' PointsToLocalOrConstantMemory function, now that
AliasAnalysis knows all the tricks that it knew.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118412 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/AliasAnalysis.cpp b/lib/Analysis/AliasAnalysis.cpp
index 472d57a..d513ebb 100644
--- a/lib/Analysis/AliasAnalysis.cpp
+++ b/lib/Analysis/AliasAnalysis.cpp
@@ -49,9 +49,10 @@
return AA->alias(LocA, LocB);
}
-bool AliasAnalysis::pointsToConstantMemory(const Location &Loc) {
+bool AliasAnalysis::pointsToConstantMemory(const Location &Loc,
+ bool OrLocal) {
assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
- return AA->pointsToConstantMemory(Loc);
+ return AA->pointsToConstantMemory(Loc, OrLocal);
}
void AliasAnalysis::deleteValue(Value *V) {
diff --git a/lib/Analysis/AliasAnalysisCounter.cpp b/lib/Analysis/AliasAnalysisCounter.cpp
index a82d959..23be94f 100644
--- a/lib/Analysis/AliasAnalysisCounter.cpp
+++ b/lib/Analysis/AliasAnalysisCounter.cpp
@@ -95,8 +95,8 @@
}
// FIXME: We could count these too...
- bool pointsToConstantMemory(const Location &Loc) {
- return getAnalysis<AliasAnalysis>().pointsToConstantMemory(Loc);
+ bool pointsToConstantMemory(const Location &Loc, bool OrLocal) {
+ return getAnalysis<AliasAnalysis>().pointsToConstantMemory(Loc, OrLocal);
}
// Forwarding functions: just delegate to a real AA implementation, counting
diff --git a/lib/Analysis/AliasDebugger.cpp b/lib/Analysis/AliasDebugger.cpp
index 4b9aefc..f15c051 100644
--- a/lib/Analysis/AliasDebugger.cpp
+++ b/lib/Analysis/AliasDebugger.cpp
@@ -113,9 +113,9 @@
return AliasAnalysis::getModRefInfo(CS1,CS2);
}
- bool pointsToConstantMemory(const Location &Loc) {
+ bool pointsToConstantMemory(const Location &Loc, bool OrLocal) {
assert(Vals.find(Loc.Ptr) != Vals.end() && "Never seen value in AA before");
- return AliasAnalysis::pointsToConstantMemory(Loc);
+ return AliasAnalysis::pointsToConstantMemory(Loc, OrLocal);
}
virtual void deleteValue(Value *V) {
diff --git a/lib/Analysis/BasicAliasAnalysis.cpp b/lib/Analysis/BasicAliasAnalysis.cpp
index 221c863..db493ee 100644
--- a/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/lib/Analysis/BasicAliasAnalysis.cpp
@@ -456,7 +456,7 @@
/// pointsToConstantMemory - Chase pointers until we find a (constant
/// global) or not.
- virtual bool pointsToConstantMemory(const Location &Loc);
+ virtual bool pointsToConstantMemory(const Location &Loc, bool OrLocal);
/// getModRefBehavior - Return the behavior when calling the given
/// call site.
@@ -517,18 +517,61 @@
return new BasicAliasAnalysis();
}
+/// pointsToConstantMemory - Returns whether the given pointer value
+/// points to memory that is local to the function, with global constants being
+/// considered local to all functions.
+bool
+BasicAliasAnalysis::pointsToConstantMemory(const Location &Loc, bool OrLocal) {
+ assert(Visited.empty() && "Visited must be cleared after use!");
-/// pointsToConstantMemory - Chase pointers until we find a (constant
-/// global) or not.
-bool BasicAliasAnalysis::pointsToConstantMemory(const Location &Loc) {
- if (const GlobalVariable *GV =
- dyn_cast<GlobalVariable>(Loc.Ptr->getUnderlyingObject()))
- // Note: this doesn't require GV to be "ODR" because it isn't legal for a
- // global to be marked constant in some modules and non-constant in others.
- // GV may even be a declaration, not a definition.
- return GV->isConstant();
+ SmallVector<const Value *, 16> Worklist;
+ Worklist.push_back(Loc.Ptr);
+ do {
+ const Value *V = Worklist.pop_back_val()->getUnderlyingObject();
+ if (!Visited.insert(V)) {
+ Visited.clear();
+ return AliasAnalysis::pointsToConstantMemory(Loc, OrLocal);
+ }
- return AliasAnalysis::pointsToConstantMemory(Loc);
+ // An alloca instruction defines local memory.
+ if (OrLocal && isa<AllocaInst>(V))
+ continue;
+
+ // A global constant counts as local memory for our purposes.
+ if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(V)) {
+ // Note: this doesn't require GV to be "ODR" because it isn't legal for a
+ // global to be marked constant in some modules and non-constant in
+ // others. GV may even be a declaration, not a definition.
+ if (!GV->isConstant()) {
+ Visited.clear();
+ return AliasAnalysis::pointsToConstantMemory(Loc, OrLocal);
+ }
+ continue;
+ }
+
+ // If both select values point to local memory, then so does the select.
+ if (const SelectInst *SI = dyn_cast<SelectInst>(V)) {
+ Worklist.push_back(SI->getTrueValue());
+ Worklist.push_back(SI->getFalseValue());
+ continue;
+ }
+
+ // If all values incoming to a phi node point to local memory, then so does
+ // the phi.
+ if (const PHINode *PN = dyn_cast<PHINode>(V)) {
+ for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
+ Worklist.push_back(PN->getIncomingValue(i));
+ continue;
+ }
+
+ // Otherwise be conservative.
+ Visited.clear();
+ return AliasAnalysis::pointsToConstantMemory(Loc, OrLocal);
+
+ } while (!Worklist.empty());
+
+ Visited.clear();
+ return true;
}
/// getModRefBehavior - Return the behavior when calling the given call site.
diff --git a/lib/Analysis/NoAliasAnalysis.cpp b/lib/Analysis/NoAliasAnalysis.cpp
index 7602149..ab7a692 100644
--- a/lib/Analysis/NoAliasAnalysis.cpp
+++ b/lib/Analysis/NoAliasAnalysis.cpp
@@ -50,7 +50,10 @@
return UnknownModRefBehavior;
}
- virtual bool pointsToConstantMemory(const Location &Loc) { return false; }
+ virtual bool pointsToConstantMemory(const Location &Loc,
+ bool OrLocal) {
+ return false;
+ }
virtual ModRefResult getModRefInfo(ImmutableCallSite CS,
const Location &Loc) {
return ModRef;
diff --git a/lib/Analysis/TypeBasedAliasAnalysis.cpp b/lib/Analysis/TypeBasedAliasAnalysis.cpp
index 0516d64..044a93f 100644
--- a/lib/Analysis/TypeBasedAliasAnalysis.cpp
+++ b/lib/Analysis/TypeBasedAliasAnalysis.cpp
@@ -138,7 +138,7 @@
private:
virtual void getAnalysisUsage(AnalysisUsage &AU) const;
virtual AliasResult alias(const Location &LocA, const Location &LocB);
- virtual bool pointsToConstantMemory(const Location &Loc);
+ virtual bool pointsToConstantMemory(const Location &Loc, bool OrLocal);
virtual ModRefResult getModRefInfo(ImmutableCallSite CS,
const Location &Loc);
virtual ModRefResult getModRefInfo(ImmutableCallSite CS1,
@@ -225,19 +225,20 @@
return NoAlias;
}
-bool TypeBasedAliasAnalysis::pointsToConstantMemory(const Location &Loc) {
+bool TypeBasedAliasAnalysis::pointsToConstantMemory(const Location &Loc,
+ bool OrLocal) {
if (!EnableTBAA)
- return AliasAnalysis::pointsToConstantMemory(Loc);
+ return AliasAnalysis::pointsToConstantMemory(Loc, OrLocal);
const MDNode *M = Loc.TBAATag;
- if (!M) return AliasAnalysis::pointsToConstantMemory(Loc);
+ if (!M) return AliasAnalysis::pointsToConstantMemory(Loc, OrLocal);
// If this is an "immutable" type, we can assume the pointer is pointing
// to constant memory.
if (TBAANode(M).TypeIsImmutable())
return true;
- return AliasAnalysis::pointsToConstantMemory(Loc);
+ return AliasAnalysis::pointsToConstantMemory(Loc, OrLocal);
}
AliasAnalysis::ModRefResult