[ThinLTO] Subsume all importing checks into a single flag

Summary:
This adds a new summary flag NotEligibleToImport that subsumes
several existing flags (NoRename, HasInlineAsmMaybeReferencingInternal
and IsNotViableToInline). It also subsumes the checking of references
on the summary that was being done during the thin link by
eligibleForImport() for each candidate. It is much more efficient to
do that checking once during the per-module summary build and record
it in the summary.

Reviewers: mehdi_amini

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D28169

llvm-svn: 291108

2 files changed, 6 insertions, 12 deletions

diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index 03aefcf5711..1a2b72e520c 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -801,12 +801,8 @@ static GlobalValueSummary::GVFlags getDecodedGVSummaryFlags(uint64_t RawFlags,
   // to getDecodedLinkage() will need to be taken into account here as above.
   auto Linkage = GlobalValue::LinkageTypes(RawFlags & 0xF); // 4 bits
   RawFlags = RawFlags >> 4;
-  bool NoRename = RawFlags & 0x1;
-  bool IsNotViableToInline = RawFlags & 0x2;
-  bool HasInlineAsmMaybeReferencingInternal = RawFlags & 0x4;
-  return GlobalValueSummary::GVFlags(Linkage, NoRename,
-                                     HasInlineAsmMaybeReferencingInternal,
-                                     IsNotViableToInline);
+  bool NotEligibleToImport = (RawFlags & 0x1) || Version < 3;
+  return GlobalValueSummary::GVFlags(Linkage, NotEligibleToImport);
 }
 
 static GlobalValue::VisibilityTypes getDecodedVisibility(unsigned Val) {
@@ -4838,9 +4834,9 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(
   }
   const uint64_t Version = Record[0];
   const bool IsOldProfileFormat = Version == 1;
-  if (!IsOldProfileFormat && Version != 2)
+  if (Version < 1 || Version > 3)
     return error("Invalid summary version " + Twine(Version) +
-                 ", 1 or 2 expected");
+                 ", 1, 2 or 3 expected");
   Record.clear();
 
   // Keep around the last seen summary to be used when we see an optional
diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index 3fed1d5aa44..19a8e24f87e 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -971,9 +971,7 @@ static unsigned getEncodedLinkage(const GlobalValue &GV) {
 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
   uint64_t RawFlags = 0;
 
-  RawFlags |= Flags.NoRename; // bool
-  RawFlags |= (Flags.IsNotViableToInline << 1);
-  RawFlags |= (Flags.HasInlineAsmMaybeReferencingInternal << 2);
+  RawFlags |= Flags.NotEligibleToImport; // bool
   // Linkage don't need to be remapped at that time for the summary. Any future
   // change to the getEncodedLinkage() function will need to be taken into
   // account here as well.
@@ -3435,7 +3433,7 @@ void ModuleBitcodeWriter::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 = 2;
+static const uint64_t INDEX_VERSION = 3;
 
 /// Emit the per-module summary section alongside the rest of
 /// the module's bitcode.