Move NoAA out of BasicAliasAnalysis.cpp into its own file, now that
it doesn't have a special relationship with BasicAliasAnalysis
anymore.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116876 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/NoAliasAnalysis.cpp b/lib/Analysis/NoAliasAnalysis.cpp
new file mode 100644
index 0000000..7602149
--- /dev/null
+++ b/lib/Analysis/NoAliasAnalysis.cpp
@@ -0,0 +1,84 @@
+//===- NoAliasAnalysis.cpp - Minimal Alias Analysis Impl ------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the default implementation of the Alias Analysis interface
+// that simply returns "I don't know" for all queries.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/Passes.h"
+#include "llvm/Pass.h"
+#include "llvm/Target/TargetData.h"
+using namespace llvm;
+
+namespace {
+ /// NoAA - This class implements the -no-aa pass, which always returns "I
+ /// don't know" for alias queries. NoAA is unlike other alias analysis
+ /// implementations, in that it does not chain to a previous analysis. As
+ /// such it doesn't follow many of the rules that other alias analyses must.
+ ///
+ struct NoAA : public ImmutablePass, public AliasAnalysis {
+ static char ID; // Class identification, replacement for typeinfo
+ NoAA() : ImmutablePass(ID) {
+ initializeNoAAPass(*PassRegistry::getPassRegistry());
+ }
+
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ }
+
+ virtual void initializePass() {
+ // Note: NoAA does not call InitializeAliasAnalysis because it's
+ // special and does not support chaining.
+ TD = getAnalysisIfAvailable<TargetData>();
+ }
+
+ virtual AliasResult alias(const Location &LocA, const Location &LocB) {
+ return MayAlias;
+ }
+
+ virtual ModRefBehavior getModRefBehavior(ImmutableCallSite CS) {
+ return UnknownModRefBehavior;
+ }
+ virtual ModRefBehavior getModRefBehavior(const Function *F) {
+ return UnknownModRefBehavior;
+ }
+
+ virtual bool pointsToConstantMemory(const Location &Loc) { return false; }
+ virtual ModRefResult getModRefInfo(ImmutableCallSite CS,
+ const Location &Loc) {
+ return ModRef;
+ }
+ virtual ModRefResult getModRefInfo(ImmutableCallSite CS1,
+ ImmutableCallSite CS2) {
+ return ModRef;
+ }
+
+ virtual void deleteValue(Value *V) {}
+ virtual void copyValue(Value *From, Value *To) {}
+
+ /// getAdjustedAnalysisPointer - This method is used when a pass implements
+ /// an analysis interface through multiple inheritance. If needed, it
+ /// should override this to adjust the this pointer as needed for the
+ /// specified pass info.
+ virtual void *getAdjustedAnalysisPointer(const void *ID) {
+ if (ID == &AliasAnalysis::ID)
+ return (AliasAnalysis*)this;
+ return this;
+ }
+ };
+} // End of anonymous namespace
+
+// Register this pass...
+char NoAA::ID = 0;
+INITIALIZE_AG_PASS(NoAA, AliasAnalysis, "no-aa",
+ "No Alias Analysis (always returns 'may' alias)",
+ true, true, true)
+
+ImmutablePass *llvm::createNoAAPass() { return new NoAA(); }