DebugInfo: Remove MDString-based type references

Eliminate DITypeIdentifierMap and make DITypeRef a thin wrapper around
DIType*.  It is no longer legal to refer to a DICompositeType by its
'identifier:', and DIBuilder no longer retains all types with an
'identifier:' automatically.

Aside from the bitcode upgrade, this is mainly removing logic to resolve
an MDString-based reference to an actualy DIType.  The commits leading
up to this have made the implicit type map in DICompileUnit's
'retainedTypes:' field superfluous.

This does not remove DITypeRef, DIScopeRef, DINodeRef, and
DITypeRefArray, or stop using them in DI-related metadata.  Although as
of this commit they aren't serving a useful purpose, there are patchces
under review to reuse them for CodeView support.

The tests in LLVM were updated with deref-typerefs.sh, which is attached
to the thread "[RFC] Lazy-loading of debug info metadata":

  http://lists.llvm.org/pipermail/llvm-dev/2016-April/098318.html

llvm-svn: 267296

1 files changed, 4 insertions, 4 deletions

diff --git a/llvm/test/Transforms/GCOVProfiling/linezero.ll b/llvm/test/Transforms/GCOVProfiling/linezero.ll
index f8903bc067c..2298f125440 100644
--- a/llvm/test/Transforms/GCOVProfiling/linezero.ll
+++ b/llvm/test/Transforms/GCOVProfiling/linezero.ll
@@ -100,13 +100,13 @@ attributes #3 = { noreturn nounwind }
 !4 = !DICompositeType(tag: DW_TAG_structure_type, name: "vector", line: 21, size: 8, align: 8, file: !5, elements: !6, identifier: "_ZTS6vector")
 !5 = !DIFile(filename: "linezero.cc", directory: "PATTERN")
 !6 = !{!7, !13}
-!7 = !DISubprogram(name: "begin", linkageName: "_ZN6vector5beginEv", line: 25, isLocal: false, isDefinition: false, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, scopeLine: 25, file: !5, scope: !"_ZTS6vector", type: !8)
+!7 = !DISubprogram(name: "begin", linkageName: "_ZN6vector5beginEv", line: 25, isLocal: false, isDefinition: false, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, scopeLine: 25, file: !5, scope: !4, type: !8)
 !8 = !DISubroutineType(types: !9)
 !9 = !{!10, !12}
 !10 = !DIDerivedType(tag: DW_TAG_pointer_type, size: 64, align: 64, baseType: !11)
 !11 = !DIBasicType(tag: DW_TAG_base_type, name: "char", size: 8, align: 8, encoding: DW_ATE_signed_char)
-!12 = !DIDerivedType(tag: DW_TAG_pointer_type, size: 64, align: 64, flags: DIFlagArtificial | DIFlagObjectPointer, baseType: !"_ZTS6vector")
-!13 = !DISubprogram(name: "end", linkageName: "_ZN6vector3endEv", line: 26, isLocal: false, isDefinition: false, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, scopeLine: 26, file: !5, scope: !"_ZTS6vector", type: !8)
+!12 = !DIDerivedType(tag: DW_TAG_pointer_type, size: 64, align: 64, flags: DIFlagArtificial | DIFlagObjectPointer, baseType: !4)
+!13 = !DISubprogram(name: "end", linkageName: "_ZN6vector3endEv", line: 26, isLocal: false, isDefinition: false, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, scopeLine: 26, file: !5, scope: !4, type: !8)
 !15 = distinct !DISubprogram(name: "test", linkageName: "_Z4testv", line: 50, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, unit: !0, scopeLine: 50, file: !5, scope: !16, type: !17, variables: !2)
 !16 = !DIFile(filename: "linezero.cc", directory: "PATTERN")
 !17 = !DISubroutineType(types: !18)
@@ -121,7 +121,7 @@ attributes #3 = { noreturn nounwind }
 !26 = !{!"clang version 3.5.0 (trunk 209871)"}
 !27 = !DILocalVariable(name: "__range", flags: DIFlagArtificial, scope: !28, type: !29)
 !28 = distinct !DILexicalBlock(line: 51, column: 0, file: !5, scope: !15)
-!29 = !DIDerivedType(tag: DW_TAG_rvalue_reference_type, baseType: !"_ZTS6vector")
+!29 = !DIDerivedType(tag: DW_TAG_rvalue_reference_type, baseType: !4)
 !30 = !DILocation(line: 0, scope: !28)
 !31 = !DILocation(line: 51, scope: !28)
 !32 = !DILocalVariable(name: "__begin", flags: DIFlagArtificial, scope: !28, type: !10)