From 5f85a9dedae7fd0aba1292c5e6b3882ca3ee1412 Mon Sep 17 00:00:00 2001
From: Peter Collingbourne <peter@pcc.me.uk>
Date: Thu, 4 May 2017 03:36:16 +0000
Subject: 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
---
 llvm/lib/Bitcode/Writer/BitcodeWriter.cpp | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

(limited to 'llvm/lib/Bitcode/Writer/BitcodeWriter.cpp')

diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index 485d9b6..1b8d81a 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -156,14 +156,14 @@ public:
       return;
     for (const auto &GUIDSummaryLists : *Index)
       // Examine all summaries for this GUID.
-      for (auto &Summary : GUIDSummaryLists.second)
+      for (auto &Summary : GUIDSummaryLists.second.SummaryList)
         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
           // For each call in the function summary, see if the call
           // is to a GUID (which means it is for an indirect call,
           // otherwise we would have a Value for it). If so, synthesize
           // a value id.
           for (auto &CallEdge : FS->calls())
-            if (CallEdge.first.isGUID())
+            if (!CallEdge.first.getValue())
               assignValueId(CallEdge.first.getGUID());
   }
 
@@ -304,7 +304,7 @@ private:
   }
   // Helper to get the valueId for the type of value recorded in VI.
   unsigned getValueId(ValueInfo VI) {
-    if (VI.isGUID())
+    if (!VI.getValue())
       return getValueId(VI.getGUID());
     return VE.getValueID(VI.getValue());
   }
@@ -358,7 +358,7 @@ public:
           Callback(Summary);
     } else {
       for (auto &Summaries : Index)
-        for (auto &Summary : Summaries.second)
+        for (auto &Summary : Summaries.second.SummaryList)
           Callback({Summaries.first, Summary.get()});
     }
   }
@@ -3270,15 +3270,14 @@ void ModuleBitcodeWriter::writePerModuleFunctionSummaryRecord(
 void ModuleBitcodeWriter::writeModuleLevelReferences(
     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
     unsigned FSModRefsAbbrev) {
-  auto Summaries =
-      Index->findGlobalValueSummaryList(GlobalValue::getGUID(V.getName()));
-  if (Summaries == Index->end()) {
+  auto VI = Index->getValueInfo(GlobalValue::getGUID(V.getName()));
+  if (!VI || VI.getSummaryList().empty()) {
     // Only declarations should not have a summary (a declaration might however
     // have a summary if the def was in module level asm).
     assert(V.isDeclaration());
     return;
   }
-  auto *Summary = Summaries->second.front().get();
+  auto *Summary = VI.getSummaryList()[0].get();
   NameVals.push_back(VE.getValueID(&V));
   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
@@ -3367,15 +3366,14 @@ void ModuleBitcodeWriter::writePerModuleGlobalValueSummary() {
     if (!F.hasName())
       report_fatal_error("Unexpected anonymous function when writing summary");
 
-    auto Summaries =
-        Index->findGlobalValueSummaryList(GlobalValue::getGUID(F.getName()));
-    if (Summaries == Index->end()) {
+    ValueInfo VI = Index->getValueInfo(GlobalValue::getGUID(F.getName()));
+    if (!VI || VI.getSummaryList().empty()) {
       // Only declarations should not have a summary (a declaration might
       // however have a summary if the def was in module level asm).
       assert(F.isDeclaration());
       continue;
     }
-    auto *Summary = Summaries->second.front().get();
+    auto *Summary = VI.getSummaryList()[0].get();
     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
   }
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