From f7e52fbdb5a7af8ea0808e98458b497125a5eca1 Mon Sep 17 00:00:00 2001
From: Reid Kleckner <rnk@google.com>
Date: Thu, 4 Jul 2019 00:03:30 +0000
Subject: Revert [ThinLTO] Optimize writeonly globals out

This reverts r365040 (git commit 5cacb914758c7f436b47c8362100f10cef14bbc4)

Speculatively reverting, since this appears to have broken check-lld on
Linux. Partial analysis in https://crbug.com/981168.

llvm-svn: 365097
---
 llvm/lib/Bitcode/Writer/BitcodeWriter.cpp | 32 +++++++++++--------------------
 1 file changed, 11 insertions(+), 21 deletions(-)

(limited to 'llvm/lib/Bitcode/Writer')

diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index 90de4688c8c..6d51d9b9d77 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -1017,7 +1017,7 @@ static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
 }
 
 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
-  uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1);
+  uint64_t RawFlags = Flags.ReadOnly;
   return RawFlags;
 }
 
@@ -3629,13 +3629,11 @@ void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
   FunctionSummary *FS = cast<FunctionSummary>(Summary);
   writeFunctionTypeMetadataRecords(Stream, FS);
 
-  auto SpecialRefCnts = FS->specialRefCounts();
   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
   NameVals.push_back(FS->instCount());
   NameVals.push_back(getEncodedFFlags(FS->fflags()));
   NameVals.push_back(FS->refs().size());
-  NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
-  NameVals.push_back(SpecialRefCnts.second); // worefcnt
+  NameVals.push_back(FS->immutableRefCount());
 
   for (auto &RI : FS->refs())
     NameVals.push_back(VE.getValueID(RI.getValue()));
@@ -3709,7 +3707,7 @@ void ModuleBitcodeWriterBase::writeModuleLevelReferences(
 // Current version for the summary.
 // This is bumped whenever we introduce changes in the way some record are
 // interpreted, like flags for instance.
-static const uint64_t INDEX_VERSION = 7;
+static const uint64_t INDEX_VERSION = 6;
 
 /// Emit the per-module summary section alongside the rest of
 /// the module's bitcode.
@@ -3751,8 +3749,7 @@ void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
-  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
-  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
+  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // immutablerefcnt
   // numrefs x valueid, n x (valueid, hotness)
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
@@ -3769,8 +3766,7 @@ void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
-  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
-  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
+  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // immutablerefcnt
   // numrefs x valueid, n x (valueid [, rel_block_freq])
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
@@ -3902,8 +3898,7 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
-  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
-  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
+  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // immutablerefcnt
   // numrefs x valueid, n x (valueid)
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
@@ -3919,8 +3914,7 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
-  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
-  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
+  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // immutablerefcnt
   // numrefs x valueid, n x (valueid, hotness)
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
@@ -4022,24 +4016,20 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
 
     // Fill in below
     NameVals.push_back(0); // numrefs
-    NameVals.push_back(0); // rorefcnt
-    NameVals.push_back(0); // worefcnt
+    NameVals.push_back(0); // immutablerefcnt
 
-    unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
+    unsigned Count = 0, ImmutableRefCnt = 0;
     for (auto &RI : FS->refs()) {
       auto RefValueId = getValueId(RI.getGUID());
       if (!RefValueId)
         continue;
       NameVals.push_back(*RefValueId);
       if (RI.isReadOnly())
-        RORefCnt++;
-      else if (RI.isWriteOnly())
-        WORefCnt++;
+        ImmutableRefCnt++;
       Count++;
     }
     NameVals[6] = Count;
-    NameVals[7] = RORefCnt;
-    NameVals[8] = WORefCnt;
+    NameVals[7] = ImmutableRefCnt;
 
     bool HasProfileData = false;
     for (auto &EI : FS->calls()) {
-- 
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