BitcodeWriter: Further unify function metadata, NFC

Further unify the handling of function-local metadata with global
metadata, by exposing the same interface in ValueEnumerator.  Both
contexts use the same accessors:

  - getMDStrings(): get the strings for this block.
  - getNonMDStrings(): get the non-strings for this block.

A future commit will start adding strings to the function-block.

llvm-svn: 265224

3 files changed, 17 insertions, 12 deletions

diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index 4ee53b51f70..26f0ac65884 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -1429,7 +1429,7 @@ static void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
 static void writeModuleMetadata(const Module &M,
                                 const ValueEnumerator &VE,
                                 BitstreamWriter &Stream) {
-  if (VE.getMDs().empty() && M.named_metadata_empty())
+  if (!VE.hasMDs() && M.named_metadata_empty())
     return;
 
   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
@@ -1442,13 +1442,14 @@ static void writeModuleMetadata(const Module &M,
 
 static void writeFunctionMetadata(const Function &F, const ValueEnumerator &VE,
                                   BitstreamWriter &Stream) {
-  ArrayRef<const Metadata *> MDs = VE.getFunctionMDs();
-  if (MDs.empty())
+  if (!VE.hasMDs())
     return;
 
   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
   SmallVector<uint64_t, 64> Record;
-  writeMetadataRecords(MDs, VE, Stream, Record);
+  assert(VE.getMDStrings().empty() &&
+         "Unexpected strings at the function-level");
+  writeMetadataRecords(VE.getNonMDStrings(), VE, Stream, Record);
   Stream.ExitBlock();
 }
 
diff --git a/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp b/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp
index 4e0a9dad2f8..5c5f05ca8f9 100644
--- a/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp
+++ b/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp
@@ -709,6 +709,7 @@ void ValueEnumerator::incorporateFunction(const Function &F) {
   InstructionCount = 0;
   NumModuleValues = Values.size();
   NumModuleMDs = MDs.size();
+  NumMDStrings = 0;
 
   // Adding function arguments to the value table.
   for (const auto &I : F.args())
diff --git a/llvm/lib/Bitcode/Writer/ValueEnumerator.h b/llvm/lib/Bitcode/Writer/ValueEnumerator.h
index 7bfe9d98655..0592382913a 100644
--- a/llvm/lib/Bitcode/Writer/ValueEnumerator.h
+++ b/llvm/lib/Bitcode/Writer/ValueEnumerator.h
@@ -65,7 +65,6 @@ private:
   std::vector<const Metadata *> MDs;
   typedef DenseMap<const Metadata *, unsigned> MetadataMapType;
   MetadataMapType MetadataMap;
-  unsigned NumMDStrings = 0;
   bool ShouldPreserveUseListOrder;
 
   typedef DenseMap<AttributeSet, unsigned> AttributeGroupMapType;
@@ -94,7 +93,8 @@ private:
 
   /// When a function is incorporated, this is the size of the Metadatas list
   /// before incorporation.
-  unsigned NumModuleMDs;
+  unsigned NumModuleMDs = 0;
+  unsigned NumMDStrings = 0;
 
   unsigned FirstFuncConstantID;
   unsigned FirstInstID;
@@ -153,15 +153,18 @@ public:
   }
 
   const ValueList &getValues() const { return Values; }
-  const std::vector<const Metadata *> &getMDs() const { return MDs; }
+
+  /// Check whether the current block has any metadata to emit.
+  bool hasMDs() const { return NumModuleMDs < MDs.size(); }
+
+  // Get the MDString metadata for this block.
   ArrayRef<const Metadata *> getMDStrings() const {
-    return makeArrayRef(MDs).slice(0, NumMDStrings);
+    return makeArrayRef(MDs).slice(NumModuleMDs, NumMDStrings);
   }
+
+  // Get the non-MDString metadata for this block.
   ArrayRef<const Metadata *> getNonMDStrings() const {
-    return makeArrayRef(MDs).slice(NumMDStrings);
-  }
-  ArrayRef<const Metadata *> getFunctionMDs() const {
-    return makeArrayRef(MDs).slice(NumModuleMDs);
+    return makeArrayRef(MDs).slice(NumModuleMDs).slice(NumMDStrings);
   }
 
   const TypeList &getTypes() const { return Types; }