[DebugInfo] Support Fortran 'use <external module>' statement.

The main change is to add a 'IsDecl' field to DIModule so
that when IsDecl is set to true, the debug info entry generated
for the module would be marked as a declaration. That way, the debugger
would look up the definition of the module in the gloabl scope.

Please see the comments in llvm/test/DebugInfo/X86/dimodule.ll
for what the debug info entries would look like.

Differential Revision: https://reviews.llvm.org/D93462

1 files changed, 5 insertions, 4 deletions

diff --git a/llvm/lib/Bitcode/Reader/MetadataLoader.cpp b/llvm/lib/Bitcode/Reader/MetadataLoader.cpp
index 3fc85b1..8cdda62 100644
--- a/llvm/lib/Bitcode/Reader/MetadataLoader.cpp
+++ b/llvm/lib/Bitcode/Reader/MetadataLoader.cpp
@@ -1565,19 +1565,20 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
   }
 
   case bitc::METADATA_MODULE: {
-    if (Record.size() < 5 || Record.size() > 8)
+    if (Record.size() < 5 || Record.size() > 9)
       return error("Invalid record");
 
-    unsigned Offset = Record.size() >= 7 ? 2 : 1;
+    unsigned Offset = Record.size() >= 8 ? 2 : 1;
     IsDistinct = Record[0];
     MetadataList.assignValue(
         GET_OR_DISTINCT(
             DIModule,
-            (Context, Record.size() >= 7 ? getMDOrNull(Record[1]) : nullptr,
+            (Context, Record.size() >= 8 ? getMDOrNull(Record[1]) : nullptr,
              getMDOrNull(Record[0 + Offset]), getMDString(Record[1 + Offset]),
              getMDString(Record[2 + Offset]), getMDString(Record[3 + Offset]),
              getMDString(Record[4 + Offset]),
-             Record.size() <= 7 ? 0 : Record[7])),
+             Record.size() <= 7 ? 0 : Record[7],
+             Record.size() <= 8 ? false : Record[8])),
         NextMetadataNo);
     NextMetadataNo++;
     break;