From 27bcd4da305ed928ac58b4f2349986242846634a Mon Sep 17 00:00:00 2001
From: "Duncan P. N. Exon Smith" <dexonsmith@apple.com>
Date: Thu, 24 Mar 2016 16:30:18 +0000
Subject: [PATCH] BitcodeWriter: Move abbreviation for GenericDINode; almost
 NFC

Simplify ValueEnumerator and WriteModuleMetadata by shifting the logic
for the METADATA_GENERIC_DEBUG abbreviation into WriteGenericDINode.
(This is just like r264302, but for GenericDINode.)

The only change is that the abbreviation is emitted later in the
bitcode, just before the first `GenericDINode` record.  This shouldn't
be observable though.

llvm-svn: 264303
---
 lib/Bitcode/Writer/BitcodeWriter.cpp   | 35 +++++++++++++-------------
 lib/Bitcode/Writer/ValueEnumerator.cpp |  3 +--
 lib/Bitcode/Writer/ValueEnumerator.h   |  2 --
 3 files changed, 19 insertions(+), 21 deletions(-)

diff --git a/lib/Bitcode/Writer/BitcodeWriter.cpp b/lib/Bitcode/Writer/BitcodeWriter.cpp
index e92b5a98d28..9977be517e7 100644
--- a/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -936,11 +936,28 @@ static void WriteDILocation(const DILocation *N, const ValueEnumerator &VE,
   Record.clear();
 }
 
+static unsigned createGenericDINodeAbbrev(BitstreamWriter &Stream) {
+  // Assume the column is usually under 128, and always output the inlined-at
+  // location (it's never more expensive than building an array size 1).
+  BitCodeAbbrev *Abbv = new BitCodeAbbrev();
+  Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
+  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
+  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
+  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
+  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
+  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
+  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
+  return Stream.EmitAbbrev(Abbv);
+}
+
 static void WriteGenericDINode(const GenericDINode *N,
                                const ValueEnumerator &VE,
                                BitstreamWriter &Stream,
                                SmallVectorImpl<uint64_t> &Record,
-                               unsigned Abbrev) {
+                               unsigned &Abbrev) {
+  if (!Abbrev)
+    Abbrev = createGenericDINodeAbbrev(Stream);
+
   Record.push_back(N->isDistinct());
   Record.push_back(N->getTag());
   Record.push_back(0); // Per-tag version field; unused for now.
@@ -1370,22 +1387,6 @@ static void WriteModuleMetadata(const Module &M,
 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
 #include "llvm/IR/Metadata.def"
 
-  if (VE.hasGenericDINode()) {
-    // Abbrev for METADATA_GENERIC_DEBUG.
-    //
-    // Assume the column is usually under 128, and always output the inlined-at
-    // location (it's never more expensive than building an array size 1).
-    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
-    Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
-    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
-    GenericDINodeAbbrev = Stream.EmitAbbrev(Abbv);
-  }
-
   SmallVector<uint64_t, 64> Record;
   for (const Metadata *MD : MDs) {
     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
diff --git a/lib/Bitcode/Writer/ValueEnumerator.cpp b/lib/Bitcode/Writer/ValueEnumerator.cpp
index 3490896a798..b6e8e57577c 100644
--- a/lib/Bitcode/Writer/ValueEnumerator.cpp
+++ b/lib/Bitcode/Writer/ValueEnumerator.cpp
@@ -280,7 +280,7 @@ static bool isIntOrIntVectorValue(const std::pair<const Value*, unsigned> &V) {
 
 ValueEnumerator::ValueEnumerator(const Module &M,
                                  bool ShouldPreserveUseListOrder)
-    : HasMDString(false), HasGenericDINode(false),
+    : HasMDString(false),
       ShouldPreserveUseListOrder(ShouldPreserveUseListOrder) {
   if (ShouldPreserveUseListOrder)
     UseListOrders = predictUseListOrder(M);
@@ -532,7 +532,6 @@ void ValueEnumerator::EnumerateMetadata(const Metadata *MD) {
     EnumerateValue(C->getValue());
 
   HasMDString |= isa<MDString>(MD);
-  HasGenericDINode |= isa<GenericDINode>(MD);
 
   // Replace the dummy ID inserted above with the correct one.  MetadataMap may
   // have changed by inserting operands, so we need a fresh lookup here.
diff --git a/lib/Bitcode/Writer/ValueEnumerator.h b/lib/Bitcode/Writer/ValueEnumerator.h
index 1b870454ad7..7665210d014 100644
--- a/lib/Bitcode/Writer/ValueEnumerator.h
+++ b/lib/Bitcode/Writer/ValueEnumerator.h
@@ -67,7 +67,6 @@ private:
   typedef DenseMap<const Metadata *, unsigned> MetadataMapType;
   MetadataMapType MetadataMap;
   bool HasMDString;
-  bool HasGenericDINode;
   bool ShouldPreserveUseListOrder;
 
   typedef DenseMap<AttributeSet, unsigned> AttributeGroupMapType;
@@ -123,7 +122,6 @@ public:
   unsigned numMDs() const { return MDs.size(); }
 
   bool hasMDString() const { return HasMDString; }
-  bool hasGenericDINode() const { return HasGenericDINode; }
 
   bool shouldPreserveUseListOrder() const { return ShouldPreserveUseListOrder; }