Add an "addUsedAAAnalyses" helper function

Summary:
Passes that call `getAnalysisIfAvailable<T>` also need to call
`addUsedIfAvailable<T>` in `getAnalysisUsage` to indicate to the
legacy pass manager that it uses `T`.  This contract was being
violated by passes that used `createLegacyPMAAResults`.  This change
fixes this by exposing a helper in AliasAnalysis.h,
`addUsedAAAnalyses`, that is complementary to createLegacyPMAAResults
and does the right thing when called from `getAnalysisUsage`.

Reviewers: chandlerc

Subscribers: mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D17010

llvm-svn: 260183
diff --git a/llvm/lib/Analysis/AliasAnalysis.cpp b/llvm/lib/Analysis/AliasAnalysis.cpp
index 8c06031..a30aedc 100644
--- a/llvm/lib/Analysis/AliasAnalysis.cpp
+++ b/llvm/lib/Analysis/AliasAnalysis.cpp
@@ -563,3 +563,14 @@
 bool llvm::isIdentifiedFunctionLocal(const Value *V) {
   return isa<AllocaInst>(V) || isNoAliasCall(V) || isNoAliasArgument(V);
 }
+
+void llvm::addUsedAAAnalyses(AnalysisUsage &AU) {
+  // This function needs to be in sync with llvm::createLegacyPMAAResults -- if
+  // more alias analyses are added to llvm::createLegacyPMAAResults, they need
+  // to be added here also.
+  AU.addUsedIfAvailable<ScopedNoAliasAAWrapperPass>();
+  AU.addUsedIfAvailable<TypeBasedAAWrapperPass>();
+  AU.addUsedIfAvailable<objcarc::ObjCARCAAWrapperPass>();
+  AU.addUsedIfAvailable<GlobalsAAWrapperPass>();
+  AU.addUsedIfAvailable<CFLAAWrapperPass>();
+}