From: Chandler Carruth <chandlerc@gmail.com>
Date: Thu, 23 Jul 2015 00:12:32 +0000 (+0000)
Subject: [GMR] Further improve the FunctionInfo API inside of GlobalsModRef, NFC.
X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=commitdiff_plain;h=603a9adf398cd62a40df1bf4fb61a5460706b988

[GMR] Further improve the FunctionInfo API inside of GlobalsModRef, NFC.

This takes the operation of merging a callee's information into the
current information and embeds it into the FunctionInfo type itself.
This is much cleaner as now we don't need to expose iteration of the
globals, etc.

Also, switched all the uses of a raw integer two maintain the mod/ref
info during the SCC walk into just directly manipulating it in the
FunctionInfo object.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242976 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Analysis/IPA/GlobalsModRef.cpp b/lib/Analysis/IPA/GlobalsModRef.cpp
index 8ffeecf155c..4ff140a6e84 100644
--- a/lib/Analysis/IPA/GlobalsModRef.cpp
+++ b/lib/Analysis/IPA/GlobalsModRef.cpp
@@ -90,9 +90,16 @@ public:
     return GlobalMRI;
   }
 
-  /// Access the entire map of mod/ref info for specific globals.
-  const std::map<const GlobalValue *, ModRefInfo> &getGlobalModRefInfo() const {
-    return GlobalInfo;
+  /// Add mod/ref info from another function into ours, saturating towards
+  /// MRI_ModRef.
+  void addFunctionInfo(const FunctionInfo &FI) {
+    addModRefInfo(FI.getModRefInfo());
+
+    if (FI.mayReadAnyGlobal())
+      setMayReadAnyGlobal();
+
+    for (const auto &G : FI.GlobalInfo)
+      addModRefInfoForGlobal(*G.first, G.second);
   }
 
   void addModRefInfoForGlobal(const GlobalValue &GV, ModRefInfo NewMRI) {
@@ -464,9 +471,7 @@ void GlobalsModRef::AnalyzeCallGraph(CallGraph &CG, Module &M) {
     }
 
     FunctionInfo &FI = FunctionInfos[SCC[0]->getFunction()];
-
     bool KnowNothing = false;
-    unsigned FunctionMRI = 0;
 
     // Collect the mod/ref properties due to called functions.  We only compute
     // one mod-ref set.
@@ -482,13 +487,13 @@ void GlobalsModRef::AnalyzeCallGraph(CallGraph &CG, Module &M) {
         if (F->doesNotAccessMemory()) {
           // Can't do better than that!
         } else if (F->onlyReadsMemory()) {
-          FunctionMRI |= MRI_Ref;
+          FI.addModRefInfo(MRI_Ref);
           if (!F->isIntrinsic())
             // This function might call back into the module and read a global -
             // consider every global as possibly being read by this function.
             FI.setMayReadAnyGlobal();
         } else {
-          FunctionMRI |= MRI_ModRef;
+          FI.addModRefInfo(MRI_ModRef);
           // Can't say anything useful unless it's an intrinsic - they don't
           // read or write global variables of the kind considered here.
           KnowNothing = !F->isIntrinsic();
@@ -501,14 +506,7 @@ void GlobalsModRef::AnalyzeCallGraph(CallGraph &CG, Module &M) {
         if (Function *Callee = CI->second->getFunction()) {
           if (FunctionInfo *CalleeFI = getFunctionInfo(Callee)) {
             // Propagate function effect up.
-            FunctionMRI |= CalleeFI->getModRefInfo();
-
-            // Incorporate callee's effects on globals into our info.
-            for (const auto &G : CalleeFI->getGlobalModRefInfo())
-              FI.addModRefInfoForGlobal(*G.first, G.second);
-
-            if (CalleeFI->mayReadAnyGlobal())
-              FI.setMayReadAnyGlobal();
+            FI.addFunctionInfo(*CalleeFI);
           } else {
             // Can't say anything about it.  However, if it is inside our SCC,
             // then nothing needs to be done.
@@ -531,10 +529,10 @@ void GlobalsModRef::AnalyzeCallGraph(CallGraph &CG, Module &M) {
 
     // Scan the function bodies for explicit loads or stores.
     for (auto *Node : SCC) {
-      if (FunctionMRI == MRI_ModRef)
+      if (FI.getModRefInfo() == MRI_ModRef)
         break; // The mod/ref lattice saturates here.
       for (Instruction &I : inst_range(Node->getFunction())) {
-        if (FunctionMRI == MRI_ModRef)
+        if (FI.getModRefInfo() == MRI_ModRef)
           break; // The mod/ref lattice saturates here.
 
         // We handle calls specially because the graph-relevant aspects are
@@ -543,13 +541,13 @@ void GlobalsModRef::AnalyzeCallGraph(CallGraph &CG, Module &M) {
           if (isAllocationFn(&I, TLI) || isFreeCall(&I, TLI)) {
             // FIXME: It is completely unclear why this is necessary and not
             // handled by the above graph code.
-            FunctionMRI |= MRI_ModRef;
+            FI.addModRefInfo(MRI_ModRef);
           } else if (Function *Callee = CS.getCalledFunction()) {
             // The callgraph doesn't include intrinsic calls.
             if (Callee->isIntrinsic()) {
               FunctionModRefBehavior Behaviour =
                   AliasAnalysis::getModRefBehavior(Callee);
-              FunctionMRI |= (Behaviour & MRI_ModRef);
+              FI.addModRefInfo(ModRefInfo(Behaviour & MRI_ModRef));
             }
           }
           continue;
@@ -558,17 +556,16 @@ void GlobalsModRef::AnalyzeCallGraph(CallGraph &CG, Module &M) {
         // All non-call instructions we use the primary predicates for whether
         // thay read or write memory.
         if (I.mayReadFromMemory())
-          FunctionMRI |= MRI_Ref;
+          FI.addModRefInfo(MRI_Ref);
         if (I.mayWriteToMemory())
-          FunctionMRI |= MRI_Mod;
+          FI.addModRefInfo(MRI_Mod);
       }
     }
 
-    if ((FunctionMRI & MRI_Mod) == 0)
+    if ((FI.getModRefInfo() & MRI_Mod) == 0)
       ++NumReadMemFunctions;
-    if (FunctionMRI == MRI_NoModRef)
+    if (FI.getModRefInfo() == MRI_NoModRef)
       ++NumNoMemFunctions;
-    FI.addModRefInfo(ModRefInfo(FunctionMRI));
 
     // Finally, now that we know the full effect on this SCC, clone the
     // information to each function in the SCC.