Add support for metadata attachments for global variables.

This patch adds an IR, assembly and bitcode representation for metadata
attachments for globals. Future patches will port existing features to use
these new attachments.

Differential Revision: http://reviews.llvm.org/D20074

llvm-svn: 271348

1 files changed, 30 insertions, 12 deletions

diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index ec3ecb2..d65e924 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -223,7 +223,10 @@ private:
                             SmallVectorImpl<uint64_t> &Record);
   void writeModuleMetadata();
   void writeFunctionMetadata(const Function &F);
-  void writeMetadataAttachment(const Function &F);
+  void writeFunctionMetadataAttachment(const Function &F);
+  void writeGlobalVariableMetadataAttachment(const GlobalVariable &GV);
+  void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
+                                    const GlobalObject &GO);
   void writeModuleMetadataStore();
   void writeOperandBundleTags();
   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
@@ -1831,24 +1834,31 @@ void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
   Stream.ExitBlock();
 }
 
-void ModuleBitcodeWriter::writeMetadataAttachment(const Function &F) {
+void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
+    SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
+  // [n x [id, mdnode]]
+  SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
+  GO.getAllMetadata(MDs);
+  for (const auto &I : MDs) {
+    Record.push_back(I.first);
+    Record.push_back(VE.getMetadataID(I.second));
+  }
+}
+
+void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
 
   SmallVector<uint64_t, 64> Record;
 
-  // Write metadata attachments
-  // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
-  SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
-  F.getAllMetadata(MDs);
-  if (!MDs.empty()) {
-    for (const auto &I : MDs) {
-      Record.push_back(I.first);
-      Record.push_back(VE.getMetadataID(I.second));
-    }
+  if (F.hasMetadata()) {
+    pushGlobalMetadataAttachment(Record, F);
     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
     Record.clear();
   }
 
+  // Write metadata attachments
+  // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
+  SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
   for (const BasicBlock &BB : F)
     for (const Instruction &I : BB) {
       MDs.clear();
@@ -2894,7 +2904,7 @@ void ModuleBitcodeWriter::writeFunction(
   writeValueSymbolTable(F.getValueSymbolTable());
 
   if (NeedsMetadataAttachment)
-    writeMetadataAttachment(F);
+    writeFunctionMetadataAttachment(F);
   if (VE.shouldPreserveUseListOrder())
     writeUseListBlock(&F);
   VE.purgeFunction();
@@ -3597,6 +3607,14 @@ void ModuleBitcodeWriter::writeModule() {
   writeValueSymbolTable(M.getValueSymbolTable(),
                         /* IsModuleLevel */ true, &FunctionToBitcodeIndex);
 
+  for (const GlobalVariable &GV : M.globals())
+    if (GV.hasMetadata()) {
+      SmallVector<uint64_t, 4> Record;
+      Record.push_back(VE.getValueID(&GV));
+      pushGlobalMetadataAttachment(Record, GV);
+      Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR_ATTACHMENT, Record);
+    }
+
   if (GenerateHash) {
     writeModuleHash(BlockStartPos);
   }