[IR] Add a boolean field in DILocation to know if a line must covered or not

Summary:
Some lines have a hit counter where they should not have one.
For example, in C++, some cleanup is adding at the end of a scope represented by a '}'.
So such a line has a hit counter where a user expects to not have one.
The goal of the patch is to add this information in DILocation which is used to get the covered lines in GCOVProfiling.cpp.
A following patch in clang will add this information when generating IR (https://reviews.llvm.org/D49916).

Reviewers: marco-c, davidxl, vsk, javed.absar, rnk

Reviewed By: rnk

Subscribers: eraman, xur, danielcdh, aprantl, rnk, dblaikie, #debug-info, vsk, llvm-commits, sylvestre.ledru

Tags: #debug-info

Differential Revision: https://reviews.llvm.org/D49915

llvm-svn: 342631
diff --git a/llvm/lib/Bitcode/Reader/MetadataLoader.cpp b/llvm/lib/Bitcode/Reader/MetadataLoader.cpp
index a48bbcc..1af17f4 100644
--- a/llvm/lib/Bitcode/Reader/MetadataLoader.cpp
+++ b/llvm/lib/Bitcode/Reader/MetadataLoader.cpp
@@ -1139,7 +1139,7 @@
     break;
   }
   case bitc::METADATA_LOCATION: {
-    if (Record.size() != 5)
+    if (Record.size() != 6)
       return error("Invalid record");
 
     IsDistinct = Record[0];
@@ -1147,8 +1147,10 @@
     unsigned Column = Record[2];
     Metadata *Scope = getMD(Record[3]);
     Metadata *InlinedAt = getMDOrNull(Record[4]);
+    bool ImplicitCode = Record[5];
     MetadataList.assignValue(
-        GET_OR_DISTINCT(DILocation, (Context, Line, Column, Scope, InlinedAt)),
+        GET_OR_DISTINCT(DILocation, (Context, Line, Column, Scope, InlinedAt,
+                                     ImplicitCode)),
         NextMetadataNo);
     NextMetadataNo++;
     break;