De-duplicate some code for creating an AARGetter suitable for the legacy PM.

[pcc]

Summary

I'm about to use this in a couple more places.

[chandlerc]

Looks good!

llvm/include/llvm/Analysis/BasicAliasAnalysis.h

 };
 
 FunctionPass *createBasicAAWrapperPass();
 
 /// A helper for the legacy pass manager to create a \c BasicAAResult object
 /// populated to the best of our ability for a particular function when inside
 /// of a \c ModulePass or a \c CallGraphSCCPass.
 BasicAAResult createLegacyPMBasicAAResult(Pass &P, Function &F);
+
+/// This class is a functor to be used in legacy module or SCC passes for
+/// computing AA results for a function. We store the results in fields so that
+/// they live long enough to be queried, but we re-use them each time.
+class LegacyAARGetter {
+  Pass &P;
+  Optional<BasicAAResult> BAR;
+  Optional<AAResults> AAR;
+
+public:
+  LegacyAARGetter(Pass &P) : P(P) {}
+  AAResults &operator()(Function &F) {
+    BAR.emplace(createLegacyPMBasicAAResult(P, F));
+    AAR.emplace(createLegacyPMAAResults(P, F, *BAR));
+    return *AAR;
+  }
+};
+
 }
 
 #endif

llvm/lib/Transforms/IPO/ArgumentPromotion.cpp

 bool ArgPromotion::runOnSCC(CallGraphSCC &SCC) {
   if (skipSCC(SCC))
     return false;
 
   // Get the callgraph information that we need to update to reflect our
   // changes.
   CallGraph &CG = getAnalysis<CallGraphWrapperPass>().getCallGraph();
 
-  // We compute dedicated AA results for each function in the SCC as needed. We
-  // use a lambda referencing external objects so that they live long enough to
-  // be queried, but we re-use them each time.
-  Optional<BasicAAResult> BAR;
-  Optional<AAResults> AAR;
-  auto AARGetter = [&](Function &F) -> AAResults & {
-    BAR.emplace(createLegacyPMBasicAAResult(*this, F));
-    AAR.emplace(createLegacyPMAAResults(*this, F, *BAR));
-    return *AAR;
-  };
+  LegacyAARGetter AARGetter(*this);
 
   bool Changed = false, LocalChange;
 
   // Iterate until we stop promoting from this SCC.
   do {
     LocalChange = false;
     // Attempt to promote arguments from all functions in this SCC.
     for (CallGraphNode *OldNode : SCC) {

llvm/lib/Transforms/IPO/FunctionAttrs.cpp

for (inst_iterator II = inst_begin(F), E = inst_end(F); II != E; ++II) {
     ReadsMemory |= I->mayReadFromMemory();
   }
 
   return ReadsMemory ? MAK_ReadOnly : MAK_ReadNone;
 }
 
 /// Deduce readonly/readnone attributes for the SCC.
 template <typename AARGetterT>
-static bool addReadAttrs(const SCCNodeSet &SCCNodes, AARGetterT AARGetter) {
+static bool addReadAttrs(const SCCNodeSet &SCCNodes, AARGetterT &&AARGetter) {
   // Check if any of the functions in the SCC read or write memory.  If they
   // write memory then they can't be marked readnone or readonly.
   bool ReadsMemory = false;
   for (Function *F : SCCNodes) {
     // Call the callable parameter to look up AA results for this function.
     AAResults &AAR = AARGetter(*F);
 
     switch (checkFunctionMemoryAccess(*F, AAR, SCCNodes)) {
static bool runImpl(CallGraphSCC &SCC, AARGetterT AARGetter) {
   }
 
   return Changed;
 }
 
 bool PostOrderFunctionAttrsLegacyPass::runOnSCC(CallGraphSCC &SCC) {
   if (skipSCC(SCC))
     return false;
-
-  // We compute dedicated AA results for each function in the SCC as needed. We
-  // use a lambda referencing external objects so that they live long enough to
-  // be queried, but we re-use them each time.
-  Optional<BasicAAResult> BAR;
-  Optional<AAResults> AAR;
-  auto AARGetter = [&](Function &F) -> AAResults & {
-    BAR.emplace(createLegacyPMBasicAAResult(*this, F));
-    AAR.emplace(createLegacyPMAAResults(*this, F, *BAR));
-    return *AAR;
-  };
-
-  return runImpl(SCC, AARGetter);
+  return runImpl(SCC, LegacyAARGetter(*this));
 }
 
 namespace {
 struct ReversePostOrderFunctionAttrsLegacyPass : public ModulePass {
   static char ID; // Pass identification, replacement for typeid
   ReversePostOrderFunctionAttrsLegacyPass() : ModulePass(ID) {
     initializeReversePostOrderFunctionAttrsLegacyPassPass(
         *PassRegistry::getPassRegistry());

llvm/lib/Transforms/IPO/Inliner.cpp

inlineCallsImpl(CallGraphSCC &SCC, CallGraph &CG,
   return Changed;
 }
 
 bool LegacyInlinerBase::inlineCalls(CallGraphSCC &SCC) {
   CallGraph &CG = getAnalysis<CallGraphWrapperPass>().getCallGraph();
   ACT = &getAnalysis<AssumptionCacheTracker>();
   PSI = getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI();
   auto &TLI = getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
-  // We compute dedicated AA results for each function in the SCC as needed. We
-  // use a lambda referencing external objects so that they live long enough to
-  // be queried, but we re-use them each time.
-  Optional<BasicAAResult> BAR;
-  Optional<AAResults> AAR;
-  auto AARGetter = [&](Function &F) -> AAResults & {
-    BAR.emplace(createLegacyPMBasicAAResult(*this, F));
-    AAR.emplace(createLegacyPMAAResults(*this, F, *BAR));
-    return *AAR;
-  };
   auto GetAssumptionCache = [&](Function &F) -> AssumptionCache & {
     return ACT->getAssumptionCache(F);
   };
   return inlineCallsImpl(SCC, CG, GetAssumptionCache, PSI, TLI, InsertLifetime,
                          [this](CallSite CS) { return getInlineCost(CS); },
-                         AARGetter, ImportedFunctionsStats);
+                         LegacyAARGetter(*this), ImportedFunctionsStats);
 }
 
 /// Remove now-dead linkonce functions at the end of
 /// processing to avoid breaking the SCC traversal.
 bool LegacyInlinerBase::doFinalization(CallGraph &CG) {
   if (InlinerFunctionImportStats != InlinerFunctionImportStatsOpts::No)
     ImportedFunctionsStats.dump(InlinerFunctionImportStats ==
                                 InlinerFunctionImportStatsOpts::Verbose);