[DebugInfo] Add calling convention support for DWARF and CodeView

Summary:
Now DISubroutineType has a 'cc' field which should be a DW_CC_ enum.  If
it is present and non-zero, the backend will emit it as a
DW_AT_calling_convention attribute. On the CodeView side, we translate
it to the appropriate enum for the LF_PROCEDURE record.

I added a new LLVM vendor specific enum to the list of DWARF calling
conventions. DWARF does not appear to attempt to standardize these, so I
assume it's OK to do this until we coordinate with GCC on how to emit
vectorcall convention functions.

Reviewers: dexonsmith, majnemer, aaboud, amccarth

Subscribers: mehdi_amini, llvm-commits

Differential Revision: http://reviews.llvm.org/D21114

llvm-svn: 272197

1 files changed, 4 insertions, 3 deletions

diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index 79d358a3281..0c2895007b9 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -2409,17 +2409,18 @@ std::error_code BitcodeReader::parseMetadata(bool ModuleLevel) {
       break;
     }
     case bitc::METADATA_SUBROUTINE_TYPE: {
-      if (Record.size() != 3)
+      if (Record.size() < 3 || Record.size() > 4)
         return error("Invalid record");
+      bool IsOldTypeRefArray = Record[0] < 2;
+      unsigned CC = (Record.size() > 3) ? Record[3] : 0;
 
       IsDistinct = Record[0] & 0x1;
-      bool IsOldTypeRefArray = Record[0] < 2;
       Metadata *Types = getMDOrNull(Record[2]);
       if (LLVM_UNLIKELY(IsOldTypeRefArray))
         Types = MetadataList.upgradeTypeRefArray(Types);
 
       MetadataList.assignValue(
-          GET_OR_DISTINCT(DISubroutineType, (Context, Record[1], Types)),
+          GET_OR_DISTINCT(DISubroutineType, (Context, Record[1], CC, Types)),
           NextMetadataNo++);
       break;
     }