[codeview] Look through typedefs in getCompleteTypeIndex

Summary:
Any time a symbol record, whether it's S_UDT, S_LOCAL, or S_[GL]DATA32,
references a record type, it should use the complete type index, even if
there's a typedef in the way.

Fixes the compiler part of PR39853.

Reviewers: zturner, aganea

Subscribers: hiraditya, arphaman, llvm-commits

Differential Revision: https://reviews.llvm.org/D55236

llvm-svn: 348902

2 files changed, 80 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
index 0ef90bc52e5..03d8777217a 100644
--- a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
@@ -2486,6 +2486,14 @@ TypeIndex CodeViewDebug::getCompleteTypeIndex(DITypeRef TypeRef) {
   if (!Ty)
     return TypeIndex::Void();
 
+  // Look through typedefs when getting the complete type index. Call
+  // getTypeIndex on the typdef to ensure that any UDTs are accumulated and are
+  // emitted only once.
+  if (Ty->getTag() == dwarf::DW_TAG_typedef)
+    (void)getTypeIndex(Ty);
+  while (Ty->getTag() == dwarf::DW_TAG_typedef)
+    Ty = cast<DIDerivedType>(Ty)->getBaseType().resolve();
+
   // If this is a non-record type, the complete type index is the same as the
   // normal type index. Just call getTypeIndex.
   switch (Ty->getTag()) {
diff --git a/llvm/test/DebugInfo/COFF/udts-complete.ll b/llvm/test/DebugInfo/COFF/udts-complete.ll
new file mode 100644
index 00000000000..1683ceabd50
--- /dev/null
+++ b/llvm/test/DebugInfo/COFF/udts-complete.ll
@@ -0,0 +1,72 @@
+; RUN: llc -filetype=obj %s -o %t.obj
+; RUN: llvm-pdbutil dump -symbols -types %t.obj | FileCheck %s
+
+; Make sure that `gv`, `Bar`, and `Baz` all point to the complete type index of
+; Foo (0x1002), and not the forward declaration index (0x1000).
+
+; C++ source:
+; struct Foo {
+;   int x;
+; };
+; typedef Foo Bar;
+; typedef Bar Baz;
+; static_assert(sizeof(Foo) == 4, "");
+; Baz gv;
+
+; CHECK:                       Types (.debug$T)
+; CHECK-NEXT: ============================================================
+; CHECK: 0x1000 | LF_STRUCTURE [size = 36] `Foo`
+; CHECK:          unique name: `.?AUFoo@@`
+; CHECK:          vtable: <no type>, base list: <no type>, field list: <no type>
+; CHECK:          options: forward ref | has unique name, sizeof 0
+; CHECK: 0x1001 | LF_FIELDLIST [size = 16]
+; CHECK:          - LF_MEMBER [name = `x`, Type = 0x0074 (int), offset = 0, attrs = public]
+; CHECK: 0x1002 | LF_STRUCTURE [size = 36] `Foo`
+; CHECK:          unique name: `.?AUFoo@@`
+; CHECK:          vtable: <no type>, base list: <no type>, field list: 0x1001
+; CHECK:          options: has unique name, sizeof 4
+; CHECK: 0x1004 | LF_UDT_SRC_LINE [size = 16]
+; CHECK:          udt = 0x1002, file = 4099, line = 1
+
+; CHECK:                           Symbols
+; CHECK: ============================================================
+; CHECK:   Mod 0000 | `.debug$S`:
+; CHECK:        0 | S_GDATA32 [size = 17] `gv`
+; CHECK:            type = 0x1002 (Foo), addr = 0000:0000
+; CHECK:        0 | S_UDT [size = 12] `Bar`
+; CHECK:            original type = 0x1002
+; CHECK:        0 | S_UDT [size = 12] `Baz`
+; CHECK:            original type = 0x1002
+; CHECK:        0 | S_UDT [size = 12] `Foo`
+; CHECK:            original type = 0x1002
+
+; ModuleID = 't.cpp'
+source_filename = "t.cpp"
+target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-windows-msvc19.14.26433"
+
+%struct.Foo = type { i32 }
+
+@"?gv@@3UFoo@@A" = dso_local global %struct.Foo zeroinitializer, align 4, !dbg !0
+
+!llvm.dbg.cu = !{!2}
+!llvm.module.flags = !{!12, !13, !14, !15}
+!llvm.ident = !{!16}
+
+!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
+!1 = distinct !DIGlobalVariable(name: "gv", linkageName: "?gv@@3UFoo@@A", scope: !2, file: !3, line: 7, type: !6, isLocal: false, isDefinition: true)
+!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "clang version 8.0.0 ", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5, nameTableKind: None)
+!3 = !DIFile(filename: "t.cpp", directory: "C:\5Csrc\5Cllvm-project\5Cbuild", checksumkind: CSK_MD5, checksum: "e21cd263d43db2ff55050be3e41e789f")
+!4 = !{}
+!5 = !{!0}
+!6 = !DIDerivedType(tag: DW_TAG_typedef, name: "Baz", file: !3, line: 5, baseType: !7)
+!7 = !DIDerivedType(tag: DW_TAG_typedef, name: "Bar", file: !3, line: 4, baseType: !8)
+!8 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "Foo", file: !3, line: 1, size: 32, flags: DIFlagTypePassByValue | DIFlagTrivial, elements: !9, identifier: ".?AUFoo@@")
+!9 = !{!10}
+!10 = !DIDerivedType(tag: DW_TAG_member, name: "x", scope: !8, file: !3, line: 2, baseType: !11, size: 32)
+!11 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!12 = !{i32 2, !"CodeView", i32 1}
+!13 = !{i32 2, !"Debug Info Version", i32 3}
+!14 = !{i32 1, !"wchar_size", i32 2}
+!15 = !{i32 7, !"PIC Level", i32 2}
+!16 = !{!"clang version 8.0.0 "}