BitcodeReader: Fix some holes in upgrade from r267296

Add tests for some missing cases to bitcode upgrade in r267296.

  - DICompositeType with an 'elements:' field, which will cause it to be
    involved in a cycle after the upgrade.

  - A DIDerivedType that references a class in 'extraData:'.

I updated test/Bitcode/dityperefs-3.8.ll with the missing cases and
regenerated test/Bitcode/dityperefs-3.8.ll.bc.

llvm-svn: 267332

lib/Bitcode/Reader/BitcodeReader.cpp

@@ -1158,6 +1158,8 @@ void BitcodeReaderMetadataList::tryToResolveCycles() {
     // Still forward references... can't resolve cycles.
     return;
 
+  bool DidReplaceTypeRefs = false;
+
   // Give up on finding a full definition for any forward decls that remain.
   for (const auto &Ref : OldTypeRefs.FwdDecls)
     OldTypeRefs.Final.insert(Ref);
@@ -1165,19 +1167,31 @@ void BitcodeReaderMetadataList::tryToResolveCycles() {
 
   // Upgrade from old type ref arrays.  In strange cases, this could add to
   // OldTypeRefs.Unknown.
-  for (const auto &Array : OldTypeRefs.Arrays)
+  for (const auto &Array : OldTypeRefs.Arrays) {
+    DidReplaceTypeRefs = true;
     Array.second->replaceAllUsesWith(resolveTypeRefArray(Array.first.get()));
+  }
+  OldTypeRefs.Arrays.clear();
 
   // Replace old string-based type refs with the resolved node, if possible.
   // If we haven't seen the node, leave it to the verifier to complain about
   // the invalid string reference.
-  for (const auto &Ref : OldTypeRefs.Unknown)
+  for (const auto &Ref : OldTypeRefs.Unknown) {
+    DidReplaceTypeRefs = true;
     if (DICompositeType *CT = OldTypeRefs.Final.lookup(Ref.first))
       Ref.second->replaceAllUsesWith(CT);
     else
       Ref.second->replaceAllUsesWith(Ref.first);
+  }
   OldTypeRefs.Unknown.clear();
 
+  // Make sure all the upgraded types are resolved.
+  if (DidReplaceTypeRefs) {
+    AnyFwdRefs = true;
+    MinFwdRef = 0;
+    MaxFwdRef = MetadataPtrs.size() - 1;
+  }
+
   if (!AnyFwdRefs)
     // Nothing to do.
     return;
@@ -2346,12 +2360,12 @@ std::error_code BitcodeReader::parseMetadata(bool ModuleLevel) {
 
       IsDistinct = Record[0];
       MetadataList.assignValue(
-          GET_OR_DISTINCT(DIDerivedType,
-                          (Context, Record[1], getMDString(Record[2]),
-                           getMDOrNull(Record[3]), Record[4],
-                           getDITypeRefOrNull(Record[5]),
-                           getDITypeRefOrNull(Record[6]), Record[7], Record[8],
-                           Record[9], Record[10], getMDOrNull(Record[11]))),
+          GET_OR_DISTINCT(
+              DIDerivedType,
+              (Context, Record[1], getMDString(Record[2]),
+               getMDOrNull(Record[3]), Record[4], getDITypeRefOrNull(Record[5]),
+               getDITypeRefOrNull(Record[6]), Record[7], Record[8], Record[9],
+               Record[10], getDITypeRefOrNull(Record[11]))),
           NextMetadataNo++);
       break;
     }

test/Bitcode/dityperefs-3.8.ll

@@ -2,7 +2,7 @@
 ; RUN: verify-uselistorder %s.bc
 
 ; Establish a stable order.
-!named = !{!0, !1, !2, !3, !4, !6, !7, !8, !9, !10, !11, !12}
+!named = !{!0, !1, !2, !3, !4, !6, !7, !8, !9, !10, !11, !12, !13, !14, !15, !16}
 
 ; CHECK:      !0 = !DIFile(filename: "path/to/file", directory: "/path/to/dir")
 ; CHECK-NEXT: !1 = !DICompositeType(tag: DW_TAG_structure_type, name: "T1"{{.*}}, identifier: "T1")
@@ -17,6 +17,10 @@
 ; CHECK-NEXT: !10 = !DIGlobalVariable(name: "G",{{.*}} type: !1,{{.*}} variable: i32* @G1)
 ; CHECK-NEXT: !11 = !DITemplateValueParameter(type: !1, value: i32* @G1)
 ; CHECK-NEXT: !12 = !DIImportedEntity(tag: DW_TAG_imported_module, name: "T2", scope: !0, entity: !1)
+; CHECK-NEXT: !13 = !DICompositeType(tag: DW_TAG_structure_type, name: "T3", file: !0, elements: !14, identifier: "T3")
+; CHECK-NEXT: !14 = !{!15}
+; CHECK-NEXT: !15 = !DISubprogram(scope: !13,
+; CHECK-NEXT: !16 = !DIDerivedType(tag: DW_TAG_ptr_to_member_type,{{.*}} extraData: !13)
 
 !0 = !DIFile(filename: "path/to/file", directory: "/path/to/dir")
 !1 = !DICompositeType(tag: DW_TAG_structure_type, name: "T1", file: !0, identifier: "T1")
@@ -31,5 +35,9 @@
 !10 = !DIGlobalVariable(name: "G", type: !"T1", isDefinition: false, variable: i32* @G1)
 !11 = !DITemplateValueParameter(type: !"T1", value: i32* @G1)
 !12 = !DIImportedEntity(tag: DW_TAG_imported_module, name: "T2", scope: !0, entity: !"T1")
+!13 = !DICompositeType(tag: DW_TAG_structure_type, name: "T3", file: !0, elements: !14, identifier: "T3")
+!14 = !{!15}
+!15 = !DISubprogram(scope: !"T3", isDefinition: false)
+!16 = !DIDerivedType(tag: DW_TAG_ptr_to_member_type, baseType: !4, extraData: !"T3")
 
 @G1 = global i32 0