Revert "[ThinLTO][Bitcode] Generate import type in bitcode (#87600)" (#94502)

This reverts commit 6262763341fcd71a2b0708cf7485f9abd1d26ba8, to prepare
for the revert of https://github.com/llvm/llvm-project/pull/92718.


https://github.com/llvm/llvm-project/pull/92718 causes LTO indexing OOM
in some applications.

1 files changed, 8 insertions, 30 deletions

diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index 3c99bde..35ea3c1 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -424,11 +424,6 @@ class IndexBitcodeWriter : public BitcodeWriterBase {
   /// The combined index to write to bitcode.
   const ModuleSummaryIndex &Index;
 
-  /// When writing combined summaries, provides the set of global value
-  /// summaries for which the value (function, function alias, etc) should be
-  /// imported as a declaration.
-  const GVSummaryPtrSet *DecSummaries = nullptr;
-
   /// When writing a subset of the index for distributed backends, client
   /// provides a map of modules to the corresponding GUIDs/summaries to write.
   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
@@ -457,16 +452,11 @@ public:
   /// Constructs a IndexBitcodeWriter object for the given combined index,
   /// writing to the provided \p Buffer. When writing a subset of the index
   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
-  /// If provided, \p ModuleToDecSummaries specifies the set of summaries for
-  /// which the corresponding functions or aliased functions should be imported
-  /// as a declaration (but not definition) for each module.
   IndexBitcodeWriter(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
                      const ModuleSummaryIndex &Index,
-                     const GVSummaryPtrSet *DecSummaries = nullptr,
                      const std::map<std::string, GVSummaryMapTy>
                          *ModuleToSummariesForIndex = nullptr)
       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
-        DecSummaries(DecSummaries),
         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
 
     // See if the StackIdIndex was already added to the StackId map and
@@ -1221,8 +1211,7 @@ static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
 
 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
 // in BitcodeReader.cpp.
-static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags,
-                                         bool ImportAsDecl = false) {
+static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
   uint64_t RawFlags = 0;
 
   RawFlags |= Flags.NotEligibleToImport; // bool
@@ -1237,8 +1226,7 @@ static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags,
 
   RawFlags |= (Flags.Visibility << 8); // 2 bits
 
-  unsigned ImportType = Flags.ImportType | ImportAsDecl;
-  RawFlags |= (ImportType << 10); // 1 bit
+  RawFlags |= (Flags.ImportType << 10); // 1 bit
 
   return RawFlags;
 }
@@ -4565,12 +4553,6 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
   unsigned AllocAbbrev = Stream.EmitAbbrev(std::move(Abbv));
 
-  auto shouldImportValueAsDecl = [&](GlobalValueSummary *GVS) -> bool {
-    if (DecSummaries == nullptr)
-      return false;
-    return DecSummaries->contains(GVS);
-  };
-
   // The aliases are emitted as a post-pass, and will point to the value
   // id of the aliasee. Save them in a vector for post-processing.
   SmallVector<AliasSummary *, 64> Aliases;
@@ -4681,8 +4663,7 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
     NameVals.push_back(*ValueId);
     assert(ModuleIdMap.count(FS->modulePath()));
     NameVals.push_back(ModuleIdMap[FS->modulePath()]);
-    NameVals.push_back(
-        getEncodedGVSummaryFlags(FS->flags(), shouldImportValueAsDecl(FS)));
+    NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
     NameVals.push_back(FS->instCount());
     NameVals.push_back(getEncodedFFlags(FS->fflags()));
     NameVals.push_back(FS->entryCount());
@@ -4731,8 +4712,7 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
     NameVals.push_back(AliasValueId);
     assert(ModuleIdMap.count(AS->modulePath()));
     NameVals.push_back(ModuleIdMap[AS->modulePath()]);
-    NameVals.push_back(
-        getEncodedGVSummaryFlags(AS->flags(), shouldImportValueAsDecl(AS)));
+    NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
     assert(AliaseeValueId);
     NameVals.push_back(AliaseeValueId);
@@ -5073,9 +5053,8 @@ void BitcodeWriter::writeModule(const Module &M,
 
 void BitcodeWriter::writeIndex(
     const ModuleSummaryIndex *Index,
-    const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex,
-    const GVSummaryPtrSet *DecSummaries) {
-  IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index, DecSummaries,
+    const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
+  IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
                                  ModuleToSummariesForIndex);
   IndexWriter.write();
 }
@@ -5130,13 +5109,12 @@ void IndexBitcodeWriter::write() {
 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
 void llvm::writeIndexToFile(
     const ModuleSummaryIndex &Index, raw_ostream &Out,
-    const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex,
-    const GVSummaryPtrSet *DecSummaries) {
+    const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
   SmallVector<char, 0> Buffer;
   Buffer.reserve(256 * 1024);
 
   BitcodeWriter Writer(Buffer);
-  Writer.writeIndex(&Index, ModuleToSummariesForIndex, DecSummaries);
+  Writer.writeIndex(&Index, ModuleToSummariesForIndex);
   Writer.writeStrtab();
 
   Out.write((char *)&Buffer.front(), Buffer.size());