Bitcode: Stop using MODULE_CODE_METADATA_VALUES

The motivation for MODULE_CODE_METADATA_VALUES was to enable an
-flto=thin scheme where:

 1. First, one function is cherry-picked from a bitcode file.
 2. Later, another function is cherry-picked.
 3. Later, ...
 4. Finally, the metadata needed by all the previous functions is
    loaded.

This was abandoned in favour of:

 1. Calculate the superset of functions needed from a Module.
 2. Link all functions at once.

Delayed metadata reading no longer serves a purpose.  It also adds
a few complication, since we can't count on metadata being properly
parsed when exiting the BitcodeReader.  After discussing with Teresa, we
agreed to remove it.

The code that depended on this was removed/updated in r264326.

llvm-svn: 264378

1 files changed, 0 insertions, 17 deletions

diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index 9977be517e7..5d051649699 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -803,23 +803,6 @@ static uint64_t WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
     Vals.clear();
   }
 
-  // Write a record indicating the number of module-level metadata IDs
-  // This is needed because the ids of metadata are assigned implicitly
-  // based on their ordering in the bitcode, with the function-level
-  // metadata ids starting after the module-level metadata ids. For
-  // function importing where we lazy load the metadata as a postpass,
-  // we want to avoid parsing the module-level metadata before parsing
-  // the imported functions.
-  {
-    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
-    Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_METADATA_VALUES));
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
-    unsigned MDValsAbbrev = Stream.EmitAbbrev(Abbv);
-    Vals.push_back(VE.numMDs());
-    Stream.EmitRecord(bitc::MODULE_CODE_METADATA_VALUES, Vals, MDValsAbbrev);
-    Vals.clear();
-  }
-
   // Emit the module's source file name.
   {
     StringEncoding Bits = getStringEncoding(M->getSourceFileName().data(),