[Assignment Tracking][3/*] Add DIAssignID metadata boilerplate

The Assignment Tracking debug-info feature is outlined in this RFC:

https://discourse.llvm.org/t/
rfc-assignment-tracking-a-better-way-of-specifying-variable-locations-in-ir

Add the DIAssignID metadata attachment boilerplate. Includes a textual-bitcode
roundtrip test and tests that the verifier and parser catch badly formed IR.

This piece of metadata links together stores (used as an attachment) and the
yet-to-be-added llvm.dbg.assign debug intrinsic (used as an operand).

Reviewed By: jmorse

Differential Revision: https://reviews.llvm.org/D132222

1 files changed, 11 insertions, 0 deletions

diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index 85ada2c..4bf881a 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -340,6 +340,8 @@ private:
                       unsigned Abbrev);
   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
                      unsigned Abbrev);
+  void writeDIAssignID(const DIAssignID *N, SmallVectorImpl<uint64_t> &Record,
+                       unsigned Abbrev);
   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
                                     SmallVectorImpl<uint64_t> &Record,
                                     unsigned Abbrev);
@@ -1949,6 +1951,15 @@ void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
   Record.clear();
 }
 
+void ModuleBitcodeWriter::writeDIAssignID(const DIAssignID *N,
+                                          SmallVectorImpl<uint64_t> &Record,
+                                          unsigned Abbrev) {
+  // There are no arguments for this metadata type.
+  Record.push_back(N->isDistinct());
+  Stream.EmitRecord(bitc::METADATA_ASSIGN_ID, Record, Abbrev);
+  Record.clear();
+}
+
 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
     unsigned Abbrev) {