IR: Use pointers instead of GUIDs to represent edges in the module summary. NFCI.

When profiling a no-op incremental link of Chromium I found that the functions
computeImportForFunction and computeDeadSymbols were consuming roughly 10% of
the profile. The goal of this change is to improve the performance of those
functions by changing the map lookups that they were previously doing into
pointer dereferences.

This is achieved by changing the ValueInfo data structure to be a pointer to
an element of the global value map owned by ModuleSummaryIndex, and changing
reference lists in the GlobalValueSummary to hold ValueInfos instead of GUIDs.
This means that a ValueInfo will take a client directly to the summary list
for a given GUID.

Differential Revision: https://reviews.llvm.org/D32471

llvm-svn: 302108

1 files changed, 23 insertions, 20 deletions

diff --git a/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp b/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
index a8341250..99f900a 100644
--- a/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
+++ b/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
@@ -37,7 +37,8 @@ using namespace llvm;
 // Walk through the operands of a given User via worklist iteration and populate
 // the set of GlobalValue references encountered. Invoked either on an
 // Instruction or a GlobalVariable (which walks its initializer).
-static void findRefEdges(const User *CurUser, SetVector<ValueInfo> &RefEdges,
+static void findRefEdges(ModuleSummaryIndex &Index, const User *CurUser,
+                         SetVector<ValueInfo> &RefEdges,
                          SmallPtrSet<const User *, 8> &Visited) {
   SmallVector<const User *, 32> Worklist;
   Worklist.push_back(CurUser);
@@ -61,7 +62,7 @@ static void findRefEdges(const User *CurUser, SetVector<ValueInfo> &RefEdges,
         // the reference set unless it is a callee. Callees are handled
         // specially by WriteFunction and are added to a separate list.
         if (!(CS && CS.isCallee(&OI)))
-          RefEdges.insert(GV);
+          RefEdges.insert(Index.getOrInsertValueInfo(GV));
         continue;
       }
       Worklist.push_back(Operand);
@@ -198,7 +199,7 @@ computeFunctionSummary(ModuleSummaryIndex &Index, const Module &M,
       if (isa<DbgInfoIntrinsic>(I))
         continue;
       ++NumInsts;
-      findRefEdges(&I, RefEdges, Visited);
+      findRefEdges(Index, &I, RefEdges, Visited);
       auto CS = ImmutableCallSite(&I);
       if (!CS)
         continue;
@@ -239,7 +240,9 @@ computeFunctionSummary(ModuleSummaryIndex &Index, const Module &M,
         // to record the call edge to the alias in that case. Eventually
         // an alias summary will be created to associate the alias and
         // aliasee.
-        CallGraphEdges[cast<GlobalValue>(CalledValue)].updateHotness(Hotness);
+        CallGraphEdges[Index.getOrInsertValueInfo(
+                           cast<GlobalValue>(CalledValue))]
+            .updateHotness(Hotness);
       } else {
         // Skip inline assembly calls.
         if (CI && CI->isInlineAsm())
@@ -254,15 +257,16 @@ computeFunctionSummary(ModuleSummaryIndex &Index, const Module &M,
             ICallAnalysis.getPromotionCandidatesForInstruction(
                 &I, NumVals, TotalCount, NumCandidates);
         for (auto &Candidate : CandidateProfileData)
-          CallGraphEdges[Candidate.Value].updateHotness(
-              getHotness(Candidate.Count, PSI));
+          CallGraphEdges[Index.getOrInsertValueInfo(Candidate.Value)]
+              .updateHotness(getHotness(Candidate.Count, PSI));
       }
     }
 
   // Explicit add hot edges to enforce importing for designated GUIDs for
   // sample PGO, to enable the same inlines as the profiled optimized binary.
   for (auto &I : F.getImportGUIDs())
-    CallGraphEdges[I].updateHotness(CalleeInfo::HotnessType::Hot);
+    CallGraphEdges[Index.getOrInsertValueInfo(I)].updateHotness(
+        CalleeInfo::HotnessType::Hot);
 
   bool NonRenamableLocal = isNonRenamableLocal(F);
   bool NotEligibleForImport =
@@ -288,7 +292,7 @@ computeVariableSummary(ModuleSummaryIndex &Index, const GlobalVariable &V,
                        DenseSet<GlobalValue::GUID> &CantBePromoted) {
   SetVector<ValueInfo> RefEdges;
   SmallPtrSet<const User *, 8> Visited;
-  findRefEdges(&V, RefEdges, Visited);
+  findRefEdges(Index, &V, RefEdges, Visited);
   bool NonRenamableLocal = isNonRenamableLocal(V);
   GlobalValueSummary::GVFlags Flags(V.getLinkage(), NonRenamableLocal,
                                     /* LiveRoot = */ false);
@@ -317,12 +321,9 @@ computeAliasSummary(ModuleSummaryIndex &Index, const GlobalAlias &A,
 
 // Set LiveRoot flag on entries matching the given value name.
 static void setLiveRoot(ModuleSummaryIndex &Index, StringRef Name) {
-  auto SummaryList =
-      Index.findGlobalValueSummaryList(GlobalValue::getGUID(Name));
-  if (SummaryList == Index.end())
-    return;
-  for (auto &Summary : SummaryList->second)
-    Summary->setLiveRoot();
+  if (ValueInfo VI = Index.getValueInfo(GlobalValue::getGUID(Name)))
+    for (auto &Summary : VI.getSummaryList())
+      Summary->setLiveRoot();
 }
 
 ModuleSummaryIndex llvm::buildModuleSummaryIndex(
@@ -446,12 +447,16 @@ ModuleSummaryIndex llvm::buildModuleSummaryIndex(
   }
 
   for (auto &GlobalList : Index) {
-    assert(GlobalList.second.size() == 1 &&
+    // Ignore entries for references that are undefined in the current module.
+    if (GlobalList.second.SummaryList.empty())
+      continue;
+
+    assert(GlobalList.second.SummaryList.size() == 1 &&
            "Expected module's index to have one summary per GUID");
-    auto &Summary = GlobalList.second[0];
+    auto &Summary = GlobalList.second.SummaryList[0];
     bool AllRefsCanBeExternallyReferenced =
         llvm::all_of(Summary->refs(), [&](const ValueInfo &VI) {
-          return !CantBePromoted.count(VI.getValue()->getGUID());
+          return !CantBePromoted.count(VI.getGUID());
         });
     if (!AllRefsCanBeExternallyReferenced) {
       Summary->setNotEligibleToImport();
@@ -461,9 +466,7 @@ ModuleSummaryIndex llvm::buildModuleSummaryIndex(
     if (auto *FuncSummary = dyn_cast<FunctionSummary>(Summary.get())) {
       bool AllCallsCanBeExternallyReferenced = llvm::all_of(
           FuncSummary->calls(), [&](const FunctionSummary::EdgeTy &Edge) {
-            auto GUID = Edge.first.isGUID() ? Edge.first.getGUID()
-                                            : Edge.first.getValue()->getGUID();
-            return !CantBePromoted.count(GUID);
+            return !CantBePromoted.count(Edge.first.getGUID());
           });
       if (!AllCallsCanBeExternallyReferenced)
         Summary->setNotEligibleToImport();