[ThinLTO] Optimize writeonly globals out

Differential revision: https://reviews.llvm.org/D63444

llvm-svn: 365040

1 files changed, 33 insertions, 14 deletions

diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index 60cc2eea8c3..fa4fbdcea5b 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -984,7 +984,8 @@ static GlobalValueSummary::GVFlags getDecodedGVSummaryFlags(uint64_t RawFlags,
 
 // Decode the flags for GlobalVariable in the summary
 static GlobalVarSummary::GVarFlags getDecodedGVarFlags(uint64_t RawFlags) {
-  return GlobalVarSummary::GVarFlags((RawFlags & 0x1) ? true : false);
+  return GlobalVarSummary::GVarFlags((RawFlags & 0x1) ? true : false,
+                                     (RawFlags & 0x2) ? true : false);
 }
 
 static GlobalValue::VisibilityTypes getDecodedVisibility(unsigned Val) {
@@ -5681,10 +5682,16 @@ void ModuleSummaryIndexBitcodeReader::parseTypeIdCompatibleVtableSummaryRecord(
     parseTypeIdCompatibleVtableInfo(Record, Slot, TypeId);
 }
 
-static void setImmutableRefs(std::vector<ValueInfo> &Refs, unsigned Count) {
-  // Read-only refs are in the end of the refs list.
-  for (unsigned RefNo = Refs.size() - Count; RefNo < Refs.size(); ++RefNo)
+static void setSpecialRefs(std::vector<ValueInfo> &Refs, unsigned ROCnt,
+                           unsigned WOCnt) {
+  // Readonly and writeonly refs are in the end of the refs list.
+  assert(ROCnt + WOCnt <= Refs.size());
+  unsigned FirstWORef = Refs.size() - WOCnt;
+  unsigned RefNo = FirstWORef - ROCnt;
+  for (; RefNo < FirstWORef; ++RefNo)
     Refs[RefNo].setReadOnly();
+  for (; RefNo < Refs.size(); ++RefNo)
+    Refs[RefNo].setWriteOnly();
 }
 
 // Eagerly parse the entire summary block. This populates the GlobalValueSummary
@@ -5711,9 +5718,9 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(unsigned ID) {
   }
   const uint64_t Version = Record[0];
   const bool IsOldProfileFormat = Version == 1;
-  if (Version < 1 || Version > 6)
+  if (Version < 1 || Version > 7)
     return error("Invalid summary version " + Twine(Version) +
-                 ". Version should be in the range [1-6].");
+                 ". Version should be in the range [1-7].");
   Record.clear();
 
   // Keep around the last seen summary to be used when we see an optional
@@ -5812,15 +5819,19 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(unsigned ID) {
       unsigned InstCount = Record[2];
       uint64_t RawFunFlags = 0;
       unsigned NumRefs = Record[3];
-      unsigned NumImmutableRefs = 0;
+      unsigned NumRORefs = 0, NumWORefs = 0;
       int RefListStartIndex = 4;
       if (Version >= 4) {
         RawFunFlags = Record[3];
         NumRefs = Record[4];
         RefListStartIndex = 5;
         if (Version >= 5) {
-          NumImmutableRefs = Record[5];
+          NumRORefs = Record[5];
           RefListStartIndex = 6;
+          if (Version >= 7) {
+            NumWORefs = Record[6];
+            RefListStartIndex = 7;
+          }
         }
       }
 
@@ -5840,7 +5851,7 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(unsigned ID) {
       std::vector<FunctionSummary::EdgeTy> Calls = makeCallList(
           ArrayRef<uint64_t>(Record).slice(CallGraphEdgeStartIndex),
           IsOldProfileFormat, HasProfile, HasRelBF);
-      setImmutableRefs(Refs, NumImmutableRefs);
+      setSpecialRefs(Refs, NumRORefs, NumWORefs);
       auto FS = llvm::make_unique<FunctionSummary>(
           Flags, InstCount, getDecodedFFlags(RawFunFlags), /*EntryCount=*/0,
           std::move(Refs), std::move(Calls), std::move(PendingTypeTests),
@@ -5891,7 +5902,8 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(unsigned ID) {
       unsigned ValueID = Record[0];
       uint64_t RawFlags = Record[1];
       unsigned RefArrayStart = 2;
-      GlobalVarSummary::GVarFlags GVF;
+      GlobalVarSummary::GVarFlags GVF(/* ReadOnly */ false,
+                                      /* WriteOnly */ false);
       auto Flags = getDecodedGVSummaryFlags(RawFlags, Version);
       if (Version >= 5) {
         GVF = getDecodedGVarFlags(Record[2]);
@@ -5948,7 +5960,7 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(unsigned ID) {
       uint64_t RawFunFlags = 0;
       uint64_t EntryCount = 0;
       unsigned NumRefs = Record[4];
-      unsigned NumImmutableRefs = 0;
+      unsigned NumRORefs = 0, NumWORefs = 0;
       int RefListStartIndex = 5;
 
       if (Version >= 4) {
@@ -5956,13 +5968,19 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(unsigned ID) {
         RefListStartIndex = 6;
         size_t NumRefsIndex = 5;
         if (Version >= 5) {
+          unsigned NumRORefsOffset = 1;
           RefListStartIndex = 7;
           if (Version >= 6) {
             NumRefsIndex = 6;
             EntryCount = Record[5];
             RefListStartIndex = 8;
+            if (Version >= 7) {
+              RefListStartIndex = 9;
+              NumWORefs = Record[8];
+              NumRORefsOffset = 2;
+            }
           }
-          NumImmutableRefs = Record[RefListStartIndex - 1];
+          NumRORefs = Record[RefListStartIndex - NumRORefsOffset];
         }
         NumRefs = Record[NumRefsIndex];
       }
@@ -5978,7 +5996,7 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(unsigned ID) {
           ArrayRef<uint64_t>(Record).slice(CallGraphEdgeStartIndex),
           IsOldProfileFormat, HasProfile, false);
       ValueInfo VI = getValueInfoFromValueId(ValueID).first;
-      setImmutableRefs(Refs, NumImmutableRefs);
+      setSpecialRefs(Refs, NumRORefs, NumWORefs);
       auto FS = llvm::make_unique<FunctionSummary>(
           Flags, InstCount, getDecodedFFlags(RawFunFlags), EntryCount,
           std::move(Refs), std::move(Edges), std::move(PendingTypeTests),
@@ -6025,7 +6043,8 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(unsigned ID) {
       uint64_t ModuleId = Record[1];
       uint64_t RawFlags = Record[2];
       unsigned RefArrayStart = 3;
-      GlobalVarSummary::GVarFlags GVF;
+      GlobalVarSummary::GVarFlags GVF(/* ReadOnly */ false,
+                                      /* WriteOnly */ false);
       auto Flags = getDecodedGVSummaryFlags(RawFlags, Version);
       if (Version >= 5) {
         GVF = getDecodedGVarFlags(Record[3]);