From f8ecdf528459b309ea55c593ed2748443d14878e Mon Sep 17 00:00:00 2001
From: "Duncan P. N. Exon Smith" <dexonsmith@apple.com>
Date: Thu, 24 Mar 2016 16:16:08 +0000
Subject: [PATCH] BitcodeWriter: Split out named metadata; almost NFC

Split writeNamedMetadata out of WriteModuleMetadata to write named
metadata, and createNamedMetadataAbbrev for the abbreviation.

There should be no effective functionality change, although the layout
of the bitcode will change.  Previously, the abbreviation was emitted at
the top of the block, but now it is delayed until immediately before the
named metadata records are emitted.

llvm-svn: 264301
---
 llvm/lib/Bitcode/Writer/BitcodeWriter.cpp | 56 +++++++++++++++++--------------
 1 file changed, 31 insertions(+), 25 deletions(-)

diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index 83dd547..fa63867 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -1301,6 +1301,36 @@ static void WriteDIImportedEntity(const DIImportedEntity *N,
   Record.clear();
 }
 
+static unsigned createNamedMetadataAbbrev(BitstreamWriter &Stream) {
+  BitCodeAbbrev *Abbv = new BitCodeAbbrev();
+  Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
+  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
+  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
+  return Stream.EmitAbbrev(Abbv);
+}
+
+static void writeNamedMetadata(const Module &M, const ValueEnumerator &VE,
+                               BitstreamWriter &Stream,
+                               SmallVectorImpl<uint64_t> &Record) {
+  if (M.named_metadata_empty())
+    return;
+
+  unsigned Abbrev = createNamedMetadataAbbrev(Stream);
+  for (const NamedMDNode &NMD : M.named_metadata()) {
+    // Write name.
+    StringRef Str = NMD.getName();
+    Record.append(Str.bytes_begin(), Str.bytes_end());
+    Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
+    Record.clear();
+
+    // Write named metadata operands.
+    for (const MDNode *N : NMD.operands())
+      Record.push_back(VE.getMetadataID(N));
+    Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
+    Record.clear();
+  }
+}
+
 static void WriteModuleMetadata(const Module &M,
                                 const ValueEnumerator &VE,
                                 BitstreamWriter &Stream) {
@@ -1355,16 +1385,6 @@ static void WriteModuleMetadata(const Module &M,
     GenericDINodeAbbrev = Stream.EmitAbbrev(Abbv);
   }
 
-  unsigned NameAbbrev = 0;
-  if (!M.named_metadata_empty()) {
-    // Abbrev for METADATA_NAME.
-    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
-    Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
-    NameAbbrev = Stream.EmitAbbrev(Abbv);
-  }
-
   SmallVector<uint64_t, 64> Record;
   for (const Metadata *MD : MDs) {
     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
@@ -1393,21 +1413,7 @@ static void WriteModuleMetadata(const Module &M,
     Record.clear();
   }
 
-  // Write named metadata.
-  for (const NamedMDNode &NMD : M.named_metadata()) {
-    // Write name.
-    StringRef Str = NMD.getName();
-    Record.append(Str.bytes_begin(), Str.bytes_end());
-    Stream.EmitRecord(bitc::METADATA_NAME, Record, NameAbbrev);
-    Record.clear();
-
-    // Write named metadata operands.
-    for (const MDNode *N : NMD.operands())
-      Record.push_back(VE.getMetadataID(N));
-    Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
-    Record.clear();
-  }
-
+  writeNamedMetadata(M, VE, Stream, Record);
   Stream.ExitBlock();
 }
 
-- 
2.7.4