Revert "[IR] Remove the DIExpression field from DIGlobalVariable."

This reverts commit 289920 (again).
I forgot to implement a Bitcode upgrade for the case where a DIGlobalVariable
has not DIExpression. Unfortunately it is not possible to safely upgrade
these variables without adding a flag to the bitcode record indicating which
version they are.
My plan of record is to roll the planned follow-up patch that adds a
unit: field to DIGlobalVariable into this patch before recomitting.
This way we only need one Bitcode upgrade for both changes (with a
version flag in the bitcode record to safely distinguish the record
formats).

Sorry for the churn!

llvm-svn: 289982

2 files changed, 5 insertions, 34 deletions

diff --git a/llvm/lib/Bitcode/Reader/MetadataLoader.cpp b/llvm/lib/Bitcode/Reader/MetadataLoader.cpp
index 96601100e34..1e28411d01e 100644
--- a/llvm/lib/Bitcode/Reader/MetadataLoader.cpp
+++ b/llvm/lib/Bitcode/Reader/MetadataLoader.cpp
@@ -982,16 +982,12 @@ Error MetadataLoader::MetadataLoaderImpl::parseMetadata(bool ModuleLevel) {
           DIGlobalVariable,
           (Context, getMDOrNull(Record[1]), getMDString(Record[2]),
            getMDString(Record[3]), getMDOrNull(Record[4]), Record[5],
-           getDITypeRefOrNull(Record[6]), Record[7], Record[8],
+           getDITypeRefOrNull(Record[6]), Record[7], Record[8], Expr,
            getMDOrNull(Record[10]), AlignInBits));
+      MetadataList.assignValue(DGV, NextMetadataNo++);
 
-      if (Expr || Attach) {
-        auto *DGVE = DIGlobalVariableExpression::getDistinct(Context, DGV, Expr);
-        MetadataList.assignValue(DGVE, NextMetadataNo++);
-        if (Attach)
-          Attach->addDebugInfo(DGVE);
-      } else
-        MetadataList.assignValue(DGV, NextMetadataNo++);
+      if (Attach)
+        Attach->addDebugInfo(DGV);
 
       break;
     }
@@ -1041,17 +1037,6 @@ Error MetadataLoader::MetadataLoaderImpl::parseMetadata(bool ModuleLevel) {
           NextMetadataNo++);
       break;
     }
-    case bitc::METADATA_GLOBAL_VAR_EXPR: {
-      if (Record.size() != 3)
-        return error("Invalid record");
-
-      IsDistinct = Record[0];
-      MetadataList.assignValue(GET_OR_DISTINCT(DIGlobalVariableExpression,
-                                               (Context, getMDOrNull(Record[1]),
-                                                getMDOrNull(Record[2]))),
-                               NextMetadataNo++);
-      break;
-    }
     case bitc::METADATA_OBJC_PROPERTY: {
       if (Record.size() != 8)
         return error("Invalid record");
diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index 2905a98f619..cff2fd0c99c 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -210,9 +210,6 @@ private:
                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
   void writeDIExpression(const DIExpression *N,
                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
-  void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
-                                       SmallVectorImpl<uint64_t> &Record,
-                                       unsigned Abbrev);
   void writeDIObjCProperty(const DIObjCProperty *N,
                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
   void writeDIImportedEntity(const DIImportedEntity *N,
@@ -1686,7 +1683,7 @@ void ModuleBitcodeWriter::writeDIGlobalVariable(
   Record.push_back(VE.getMetadataOrNullID(N->getType()));
   Record.push_back(N->isLocalToUnit());
   Record.push_back(N->isDefinition());
-  Record.push_back(/* expr */ 0);
+  Record.push_back(VE.getMetadataOrNullID(N->getRawExpr()));
   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
   Record.push_back(N->getAlignInBits());
 
@@ -1738,17 +1735,6 @@ void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
   Record.clear();
 }
 
-void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
-    const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
-    unsigned Abbrev) {
-  Record.push_back(N->isDistinct());
-  Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
-  Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
-  
-  Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
-  Record.clear();
-}
-
 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
                                               SmallVectorImpl<uint64_t> &Record,
                                               unsigned Abbrev) {