[CodeView] only output S_UDT for symbols that have strong variable references.

[zturner]

Summary

There's something still wrong with this patch because MSVC's linker says "warning LNK4209: debugging information corrupt; recompile module; linking object as if no debug info" when I try to build clang-cl. Is there anything obviously wrong here, or am I misunderstanding something fundamental?

[zturner]

This version of the patch seems to improve things. Previously it would fail even with simple tools like llvm-readobj etc Now I can get almost everything to link correctly, but clang still fails.

[rnk]

llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

2268

I'd try reverting this change and see if that fixes the linker warnings.

[zturner]

I'm still seeing it with this updated version of the patch. Also worth pointing out that it starts with warnings, but at the end it errors out with LNK1103

[zturner]

I can confirm that the patch I have at home to solve this does not exhibit the problem. I'm using 15.2 instead of 15.3, so that's one possibility. Another possibility is a functional difference. I'll test the uploaded version of the patch on my home machine as well and see if it succeeds.

llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.h

class LLVM_LIBRARY_VISIBILITY CodeViewDebug : public DebugHandlerBase {
   unsigned TypeEmissionLevel = 0;
 
   codeview::TypeIndex VBPType;
 
   const DISubprogram *CurrentSubprogram = nullptr;
 
   // The UDTs we have seen while processing types; each entry is a pair of type
   // index and type name.
-  std::vector<std::pair<std::string, codeview::TypeIndex>> LocalUDTs,
-      GlobalUDTs;
+  struct UDTRef {
+    explicit UDTRef(std::string Name, codeview::TypeIndex UnderlyingTI)
+        : Name(std::move(Name)), UnderlyingTI(UnderlyingTI) {}
+
+    std::string Name;
+    codeview::TypeIndex UnderlyingTI;
+    bool HasStrongRef = false;
+  };
+  std::vector<UDTRef *> LocalUDTs;
+  std::vector<UDTRef *> GlobalUDTs;
+  DenseMap<const DIType *, std::unique_ptr<UDTRef>> UDTLookup;
+  codeview::TypeIndex strongRef(const DIVariable *Var);
+  void strongTypeRef(DITypeRef Type);
 
   using FileToFilepathMapTy = std::map<const DIFile *, std::string>;
   FileToFilepathMapTy FileToFilepathMap;
 
   StringRef getFullFilepath(const DIFile *S);
 
   unsigned maybeRecordFile(const DIFile *F);
 
class LLVM_LIBRARY_VISIBILITY CodeViewDebug : public DebugHandlerBase {
   void emitInlineeLinesSubsection();
 
   void emitDebugInfoForFunction(const Function *GV, FunctionInfo &FI);
 
   void emitDebugInfoForGlobals();
 
   void emitDebugInfoForRetainedTypes();
 
-  void emitDebugInfoForUDTs(
-      ArrayRef<std::pair<std::string, codeview::TypeIndex>> UDTs);
+  void emitDebugInfoForUDTs(ArrayRef<UDTRef *> UDTs);
 
   void emitDebugInfoForGlobal(const DIGlobalVariable *DIGV,
                               const GlobalVariable *GV, MCSymbol *GVSym);
 
   /// Opens a subsection of the given kind in a .debug$S codeview section.
   /// Returns an end label for use with endCVSubsection when the subsection is
   /// finished.
   MCSymbol *beginCVSubsection(codeview::DebugSubsectionKind Kind);

llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

void CodeViewDebug::beginFunctionImpl(const MachineFunction *MF) {
 
   // Record beginning of function if we have a non-empty prologue.
   if (PrologEndLoc && !EmptyPrologue) {
     DebugLoc FnStartDL = PrologEndLoc.getFnDebugLoc();
     maybeRecordLocation(FnStartDL, MF);
   }
 }
 
-void CodeViewDebug::addToUDTs(const DIType *Ty, TypeIndex TI) {
+void CodeViewDebug::addToUDTs(const DIType *Ty, TypeIndex UnderlyingTI) {
   // Don't record empty UDTs.
   if (Ty->getName().empty())
     return;
 
+  // Don't record UDTs that have already been recorded.
+  if (UDTLookup.find(Ty) != UDTLookup.end())
+    return;
+
   SmallVector<StringRef, 5> QualifiedNameComponents;
   const DISubprogram *ClosestSubprogram = getQualifiedNameComponents(
       Ty->getScope().resolve(), QualifiedNameComponents);
 
   std::string FullyQualifiedName =
       getQualifiedName(QualifiedNameComponents, getPrettyScopeName(Ty));
 
+  auto UDT =
+      llvm::make_unique<UDTRef>(std::move(FullyQualifiedName), UnderlyingTI);
+  UDTRef *PtrUdt = UDT.get();
+  UDTLookup[Ty] = std::move(UDT);
   if (ClosestSubprogram == nullptr)
-    GlobalUDTs.emplace_back(std::move(FullyQualifiedName), TI);
+    GlobalUDTs.push_back(PtrUdt);
   else if (ClosestSubprogram == CurrentSubprogram)
-    LocalUDTs.emplace_back(std::move(FullyQualifiedName), TI);
+    LocalUDTs.push_back(PtrUdt);
 
   // TODO: What if the ClosestSubprogram is neither null or the current
   // subprogram?  Currently, the UDT just gets dropped on the floor.
   //
   // The current behavior is not desirable.  To get maximal fidelity, we would
   // need to perform all type translation before beginning emission of .debug$S
   // and then make LocalUDTs a member of FunctionInfo
 }
 
+codeview::TypeIndex CodeViewDebug::strongRef(const DIVariable *Var) {
+  // Make sure to call getCompleteTypeIndex first so that the entire type
+  // hierarchy is lowered.
+  TypeIndex Result = getCompleteTypeIndex(Var->getType());
+  strongTypeRef(Var->getType());
+  return Result;
+}
+
+void CodeViewDebug::strongTypeRef(DITypeRef Type) {
+  DIType *Ty = Type.resolve();
+  if (!Ty)
+    return;
+
+  switch (Ty->getTag()) {
+  case dwarf::DW_TAG_class_type:
+  case dwarf::DW_TAG_structure_type:
+  case dwarf::DW_TAG_union_type:
+  case dwarf::DW_TAG_typedef: {
+    auto Iter = UDTLookup.find(Ty);
+    if (Iter != UDTLookup.end())
+      Iter->second->HasStrongRef = true;
+    return;
+  }
+  case dwarf::DW_TAG_array_type:
+    strongTypeRef(cast<DICompositeType>(Ty)->getBaseType());
+    return;
+  case dwarf::DW_TAG_pointer_type:
+    if (cast<DIDerivedType>(Ty)->getName() == "__vtbl_ptr_type")
+      return;
+    LLVM_FALLTHROUGH;
+  case dwarf::DW_TAG_reference_type:
+  case dwarf::DW_TAG_rvalue_reference_type:
+  case dwarf::DW_TAG_const_type:
+  case dwarf::DW_TAG_volatile_type:
+    strongTypeRef(cast<DIDerivedType>(Ty)->getBaseType());
+    return;
+  default:
+    return;
+  }
+}
+
 TypeIndex CodeViewDebug::lowerType(const DIType *Ty, const DIType *ClassTy) {
   // Generic dispatch for lowering an unknown type.
   switch (Ty->getTag()) {
   case dwarf::DW_TAG_array_type:
     return lowerTypeArray(cast<DICompositeType>(Ty));
   case dwarf::DW_TAG_typedef:
     return lowerTypeAlias(cast<DIDerivedType>(Ty));
   case dwarf::DW_TAG_base_type:
void CodeViewDebug::emitLocalVariable(const LocalVariable &Var) {
 
   LocalSymFlags Flags = LocalSymFlags::None;
   if (Var.DIVar->isParameter())
     Flags |= LocalSymFlags::IsParameter;
   if (Var.DefRanges.empty())
     Flags |= LocalSymFlags::IsOptimizedOut;
 
   OS.AddComment("TypeIndex");
-  TypeIndex TI = getCompleteTypeIndex(Var.DIVar->getType());
-  OS.EmitIntValue(TI.getIndex(), 4);
+  OS.EmitIntValue(strongRef(Var.DIVar).getIndex(), 4);
   OS.AddComment("Flags");
   OS.EmitIntValue(static_cast<uint16_t>(Flags), 2);
   // Truncate the name so we won't overflow the record length field.
   emitNullTerminatedSymbolName(OS, Var.DIVar->getName());
   OS.EmitLabel(LocalEnd);
 
   // Calculate the on disk prefix of the appropriate def range record. The
   // records and on disk formats are described in SymbolRecords.h. BytePrefix

 }
 
 void CodeViewDebug::endCVSubsection(MCSymbol *EndLabel) {
   OS.EmitLabel(EndLabel);
   // Every subsection must be aligned to a 4-byte boundary.
   OS.EmitValueToAlignment(4);
 }
 
-void CodeViewDebug::emitDebugInfoForUDTs(
-    ArrayRef<std::pair<std::string, TypeIndex>> UDTs) {
-  for (const std::pair<std::string, codeview::TypeIndex> &UDT : UDTs) {
+void CodeViewDebug::emitDebugInfoForUDTs(ArrayRef<UDTRef *> UDTs) {
+  for (const UDTRef *UDT : UDTs) {
+    if (!UDT->HasStrongRef)
+      continue;
+
     MCSymbol *UDTRecordBegin = MMI->getContext().createTempSymbol(),
              *UDTRecordEnd = MMI->getContext().createTempSymbol();
     OS.AddComment("Record length");
     OS.emitAbsoluteSymbolDiff(UDTRecordEnd, UDTRecordBegin, 2);
     OS.EmitLabel(UDTRecordBegin);
 
     OS.AddComment("Record kind: S_UDT");
     OS.EmitIntValue(unsigned(SymbolKind::S_UDT), 2);
 
     OS.AddComment("Type");
-    OS.EmitIntValue(UDT.second.getIndex(), 4);
+    OS.EmitIntValue(UDT->UnderlyingTI.getIndex(), 4);
 
-    emitNullTerminatedSymbolName(OS, UDT.first);
+    emitNullTerminatedSymbolName(OS, UDT->Name);
     OS.EmitLabel(UDTRecordEnd);
   }
 }
 
 void CodeViewDebug::emitDebugInfoForGlobals() {
   DenseMap<const DIGlobalVariableExpression *, const GlobalVariable *>
       GlobalMap;
   for (const GlobalVariable &GV : MMI->getModule()->globals()) {
if (GV->isThreadLocal()) {
       OS.AddComment("Record kind: S_GTHREAD32");
       OS.EmitIntValue(unsigned(SymbolKind::S_GTHREAD32), 2);
     } else {
       OS.AddComment("Record kind: S_GDATA32");
       OS.EmitIntValue(unsigned(SymbolKind::S_GDATA32), 2);
     }
   }
   OS.AddComment("Type");
-  OS.EmitIntValue(getCompleteTypeIndex(DIGV->getType()).getIndex(), 4);
+  OS.EmitIntValue(strongRef(DIGV).getIndex(), 4);
   OS.AddComment("DataOffset");
   OS.EmitCOFFSecRel32(GVSym, /*Offset=*/0);
   OS.AddComment("Segment");
   OS.EmitCOFFSectionIndex(GVSym);
   OS.AddComment("Name");
   emitNullTerminatedSymbolName(OS, DIGV->getName());
   OS.EmitLabel(DataEnd);
 }

llvm/test/DebugInfo/COFF/udts.ll

 ; RUN: llc < %s -filetype=obj | llvm-readobj - -codeview | FileCheck %s
 source_filename = "test/DebugInfo/COFF/udts.ll"
 target datalayout = "e-m:x-p:32:32-i64:64-f80:32-n8:16:32-a:0:32-S32"
 target triple = "i686-pc-windows-msvc18.0.0"
 ; C++ source to regenerate:
 ; $ cat t.cpp
 ; void f() {
-;   typedef int FOO;
+;   typedef int FOO;  // Referenced by local -> S_UDT
+;   typedef int BAR;  // Unreferenced -> no S_UDT
 ;   FOO f;
 ; }
 ;
-; struct S { int x; };
-; float g(S *s) {
+; struct S {
+;   typedef int SREF;   // Referenced by a member variable -> S_UDT
+;   typedef int UREF;   // Unreferenced -> no S_UDT
+;   typedef float RREF; // Referenced by function return value -> no S_UDT
+;   RREF foo() { return 7.0f; }
+;   SREF x;
+; };
+; float g(S *s) {     // Referenced by pointer -> S_UDT
 ;   union pun { int x; float f; } p;
 ;   p.x = s->x;
-;   return p.f;
+;   return p.f + s->foo();
 ; }
+;
+; // Referenced by global variable -> S_UDT
 ; typedef struct { int x; } U;
 ; U u;
+;
+; // Unreferenced -> no S_UDT
+; struct V {
+;   int x;
+; };
+;
+; struct W {
+;   int x;
+; };
+; 
+; typedef W* PTR;
+; void h(PTR p) {}
+;
 
-; CHECK:      {{.*}}Proc{{.*}}Sym {
+; CHECK:      GlobalProcIdSym {
 ; CHECK:        DisplayName: f
 ; CHECK:        LinkageName: ?f@@YAXXZ
 ; CHECK:      }
 ; CHECK:      UDTSym {
+; CHECK-NOT:    UDTName: f::BAR
 ; CHECK-NEXT:   Kind: S_UDT (0x1108)
 ; CHECK-NEXT:   Type: int (0x74)
 ; CHECK-NEXT:   UDTName: f::FOO
 ; CHECK-NEXT: }
 ; CHECK-NEXT: ProcEnd {
 
-; CHECK:      {{.*}}Proc{{.*}}Sym {
+; CHECK:      GlobalProcIdSym {
 ; CHECK:        DisplayName: g
-; CHECK:        LinkageName: ?g@@YAMPEAUS@@@Z
+; CHECK:        LinkageName: ?g@@YAMPAUS@@@Z
 ; CHECK:      }
 ; CHECK:      UDTSym {
 ; CHECK-NEXT:   Kind: S_UDT (0x1108)
 ; CHECK-NEXT:   Type: g::pun (0x{{[0-9A-F]+}})
 ; CHECK-NEXT:   UDTName: g::pun
 ; CHECK-NEXT: }
 ; CHECK-NEXT: ProcEnd {
 
 ; CHECK:      Subsection
+; CHECK:      SubSectionType: Symbols
+; CHECK:      GlobalProcIdSym
+; CHECK:      LinkageName: ?h@@YAXPAUW@@@Z
+
 ; CHECK-NOT:  {{.*}}Proc{{.*}}Sym
+
+; CHECK:      Subsection
+; CHECK:      SubSectionType: Symbols
+; CHECK:      GlobalData
+; CHECK:      LinkageName: ?u@@3UU@@A
+
+; CHECK:      Subsection
 ; CHECK:      UDTSym {
 ; CHECK-NEXT:   Kind: S_UDT (0x1108)
-; CHECK-NEXT: Type: S (0x{{[0-9A-F]+}})
-; CHECK-NEXT: UDTName: S
-; CHECK:      UDTSym {
+; CHECK-NEXT:   Type: S (0x1009)
+; CHECK-NEXT:   UDTName: S
+; CHECK-NEXT: }
+; CHECK-NEXT: UDTSym {
 ; CHECK-NEXT:   Kind: S_UDT (0x1108)
-; CHECK-NEXT: Type: <unnamed-tag> (0x{{[0-9A-F]+}})
-; CHECK-NEXT: UDTName: U
-; CHECK-NOT: UDTSym {
+; CHECK-NEXT:   Type: W* (0x1013)
+; CHECK-NEXT:   UDTName: PTR
+; CHECK-NEXT: }
+; CHECK-NEXT: UDTSym {
+; CHECK-NEXT:   Kind: S_UDT (0x1108)
+; CHECK-NEXT:   Type: U (0x1017)
+; CHECK-NEXT:   UDTName: U
+; CHECK-NEXT: }
+; CHECK-NOT:  UDTSym
+
+; ModuleID = 't.cpp'
+source_filename = "t.cpp"
+target datalayout = "e-m:x-p:32:32-i64:64-f80:32-n8:16:32-a:0:32-S32"
+target triple = "i686-pc-windows-msvc19.11.25506"
 
 %struct.U = type { i32 }
 %struct.S = type { i32 }
 %union.pun = type { i32 }
+%struct.W = type { i32 }
+
+$"\01?foo@S@@QAEMXZ" = comdat any
 
 @"\01?u@@3UU@@A" = global %struct.U zeroinitializer, align 4, !dbg !0
 
-; Function Attrs: nounwind uwtable
-define void @"\01?f@@YAXXZ"() #0 !dbg !15 {
+; Function Attrs: noinline nounwind optnone
+define void @"\01?f@@YAXXZ"() #0 !dbg !16 {
 entry:
   %f = alloca i32, align 4
-  call void @llvm.dbg.declare(metadata i32* %f, metadata !18, metadata !20), !dbg !21
-  ret void, !dbg !22
+  call void @llvm.dbg.declare(metadata i32* %f, metadata !19, metadata !21), !dbg !22
+  ret void, !dbg !23
 }
 
-; Function Attrs: nounwind readnone
+; Function Attrs: nounwind readnone speculatable
 declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
 
-; Function Attrs: nounwind uwtable
-define float @"\01?g@@YAMPEAUS@@@Z"(%struct.S* %s) #0 !dbg !23 {
+; Function Attrs: noinline optnone
+define float @"\01?g@@YAMPAUS@@@Z"(%struct.S* %s) #2 !dbg !24 {
 entry:
-  %s.addr = alloca %struct.S*, align 8
+  %s.addr = alloca %struct.S*, align 4
   %p = alloca %union.pun, align 4
-  store %struct.S* %s, %struct.S** %s.addr, align 8
-  call void @llvm.dbg.declare(metadata %struct.S** %s.addr, metadata !31, metadata !20), !dbg !32
-  call void @llvm.dbg.declare(metadata %union.pun* %p, metadata !33, metadata !20), !dbg !38
-  %0 = load %struct.S*, %struct.S** %s.addr, align 8, !dbg !39
-  %x = getelementptr inbounds %struct.S, %struct.S* %0, i32 0, i32 0, !dbg !40
-  %1 = load i32, i32* %x, align 4, !dbg !40
-  %x1 = bitcast %union.pun* %p to i32*, !dbg !41
-  store i32 %1, i32* %x1, align 4, !dbg !42
-  %f = bitcast %union.pun* %p to float*, !dbg !43
-  %2 = load float, float* %f, align 4, !dbg !43
-  ret float %2, !dbg !44
+  store %struct.S* %s, %struct.S** %s.addr, align 4
+  call void @llvm.dbg.declare(metadata %struct.S** %s.addr, metadata !39, metadata !21), !dbg !40
+  call void @llvm.dbg.declare(metadata %union.pun* %p, metadata !41, metadata !21), !dbg !46
+  %0 = load %struct.S*, %struct.S** %s.addr, align 4, !dbg !47
+  %x = getelementptr inbounds %struct.S, %struct.S* %0, i32 0, i32 0, !dbg !48
+  %1 = load i32, i32* %x, align 4, !dbg !48
+  %x1 = bitcast %union.pun* %p to i32*, !dbg !49
+  store i32 %1, i32* %x1, align 4, !dbg !50
+  %f = bitcast %union.pun* %p to float*, !dbg !51
+  %2 = load float, float* %f, align 4, !dbg !51
+  %3 = load %struct.S*, %struct.S** %s.addr, align 4, !dbg !52
+  %call = call x86_thiscallcc float @"\01?foo@S@@QAEMXZ"(%struct.S* %3), !dbg !53
+  %add = fadd float %2, %call, !dbg !54
+  ret float %add, !dbg !55
+}
+
+; Function Attrs: noinline nounwind optnone
+define linkonce_odr x86_thiscallcc float @"\01?foo@S@@QAEMXZ"(%struct.S* %this) #0 comdat align 2 !dbg !56 {
+entry:
+  %this.addr = alloca %struct.S*, align 4
+  store %struct.S* %this, %struct.S** %this.addr, align 4
+  call void @llvm.dbg.declare(metadata %struct.S** %this.addr, metadata !57, metadata !21), !dbg !58
+  %this1 = load %struct.S*, %struct.S** %this.addr, align 4
+  ret float 7.000000e+00, !dbg !59
+}
+
+; Function Attrs: noinline nounwind optnone
+define void @"\01?h@@YAXPAUW@@@Z"(%struct.W* %p) #0 !dbg !60 {
+entry:
+  %p.addr = alloca %struct.W*, align 4
+  store %struct.W* %p, %struct.W** %p.addr, align 4
+  call void @llvm.dbg.declare(metadata %struct.W** %p.addr, metadata !66, metadata !21), !dbg !67
+  ret void, !dbg !68
 }
 
-attributes #0 = { nounwind uwtable "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
-attributes #1 = { nounwind readnone }
+attributes #0 = { noinline nounwind optnone "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="pentium4" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { nounwind readnone speculatable }
+attributes #2 = { noinline optnone "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="pentium4" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
 
 !llvm.dbg.cu = !{!2}
-!llvm.module.flags = !{!11, !12, !13}
-!llvm.ident = !{!14}
+!llvm.module.flags = !{!11, !12, !13, !14}
+!llvm.ident = !{!15}
 
-!0 = distinct !DIGlobalVariableExpression(var: !1)
-!1 = !DIGlobalVariable(name: "u", linkageName: "\01?u@@3UU@@A", scope: !2, file: !3, line: 13, type: !6, isLocal: false, isDefinition: true)
-!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "clang version 3.9.0 ", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5)
-!3 = !DIFile(filename: "t.cpp", directory: "D:\5Csrc\5Cllvm\5Cbuild")
+!0 = !DIGlobalVariableExpression(var: !1)
+!1 = distinct !DIGlobalVariable(name: "u", linkageName: "\01?u@@3UU@@A", scope: !2, file: !3, line: 22, type: !6, isLocal: false, isDefinition: true)
+!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "clang version 6.0.0 ", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5)
+!3 = !DIFile(filename: "t.cpp", directory: "D:\5Csrc\5Cllvmbuild\5Cninja", checksumkind: CSK_MD5, checksum: "09e294c28bef47c70c41b94dcac823a3")
 !4 = !{}
 !5 = !{!0}
-!6 = !DIDerivedType(tag: DW_TAG_typedef, name: "U", file: !3, line: 12, baseType: !7)
-!7 = distinct !DICompositeType(tag: DW_TAG_structure_type, file: !3, line: 12, size: 32, align: 32, elements: !8, identifier: ".?AUU@@")
+!6 = !DIDerivedType(tag: DW_TAG_typedef, name: "U", file: !3, line: 21, baseType: !7)
+!7 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "U", file: !3, line: 21, size: 32, elements: !8, identifier: ".?AUU@@")
 !8 = !{!9}
-!9 = !DIDerivedType(tag: DW_TAG_member, name: "x", scope: !7, file: !3, line: 12, baseType: !10, size: 32, align: 32)
-!10 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
-!11 = !{i32 2, !"CodeView", i32 1}
-!12 = !{i32 2, !"Debug Info Version", i32 3}
-!13 = !{i32 1, !"PIC Level", i32 2}
-!14 = !{!"clang version 3.9.0 "}
-!15 = distinct !DISubprogram(name: "f", linkageName: "\01?f@@YAXXZ", scope: !3, file: !3, line: 1, type: !16, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: false, unit: !2, variables: !4)
-!16 = !DISubroutineType(types: !17)
-!17 = !{null}
-!18 = !DILocalVariable(name: "f", scope: !15, file: !3, line: 3, type: !19)
-!19 = !DIDerivedType(tag: DW_TAG_typedef, name: "FOO", scope: !15, file: !3, line: 2, baseType: !10)
-!20 = !DIExpression()
-!21 = !DILocation(line: 3, column: 7, scope: !15)
-!22 = !DILocation(line: 4, column: 1, scope: !15)
-!23 = distinct !DISubprogram(name: "g", linkageName: "\01?g@@YAMPEAUS@@@Z", scope: !3, file: !3, line: 7, type: !24, isLocal: false, isDefinition: true, scopeLine: 7, flags: DIFlagPrototyped, isOptimized: false, unit: !2, variables: !4)
-!24 = !DISubroutineType(types: !25)
-!25 = !{!26, !27}
-!26 = !DIBasicType(name: "float", size: 32, align: 32, encoding: DW_ATE_float)
-!27 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !28, size: 64, align: 64)
-!28 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "S", file: !3, line: 6, size: 32, align: 32, elements: !29, identifier: ".?AUS@@")
-!29 = !{!30}
-!30 = !DIDerivedType(tag: DW_TAG_member, name: "x", scope: !28, file: !3, line: 6, baseType: !10, size: 32, align: 32)
-!31 = !DILocalVariable(name: "s", arg: 1, scope: !23, file: !3, line: 7, type: !27)
-!32 = !DILocation(line: 7, column: 12, scope: !23)
-!33 = !DILocalVariable(name: "p", scope: !23, file: !3, line: 8, type: !34)
-!34 = distinct !DICompositeType(tag: DW_TAG_union_type, name: "pun", scope: !23, file: !3, line: 8, size: 32, align: 32, elements: !35)
-!35 = !{!36, !37}
-!36 = !DIDerivedType(tag: DW_TAG_member, name: "x", scope: !34, file: !3, line: 8, baseType: !10, size: 32, align: 32)
-!37 = !DIDerivedType(tag: DW_TAG_member, name: "f", scope: !34, file: !3, line: 8, baseType: !26, size: 32, align: 32)
-!38 = !DILocation(line: 8, column: 33, scope: !23)
-!39 = !DILocation(line: 9, column: 9, scope: !23)
-!40 = !DILocation(line: 9, column: 12, scope: !23)
-!41 = !DILocation(line: 9, column: 5, scope: !23)
-!42 = !DILocation(line: 9, column: 7, scope: !23)
-!43 = !DILocation(line: 10, column: 12, scope: !23)
-!44 = !DILocation(line: 10, column: 3, scope: !23)
-
+!9 = !DIDerivedType(tag: DW_TAG_member, name: "x", scope: !7, file: !3, line: 21, baseType: !10, size: 32)
+!10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!11 = !{i32 1, !"NumRegisterParameters", i32 0}
+!12 = !{i32 2, !"CodeView", i32 1}
+!13 = !{i32 2, !"Debug Info Version", i32 3}
+!14 = !{i32 1, !"wchar_size", i32 2}
+!15 = !{!"clang version 6.0.0 "}
+!16 = distinct !DISubprogram(name: "f", linkageName: "\01?f@@YAXXZ", scope: !3, file: !3, line: 1, type: !17, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: false, unit: !2, variables: !4)
+!17 = !DISubroutineType(types: !18)
+!18 = !{null}
+!19 = !DILocalVariable(name: "f", scope: !16, file: !3, line: 4, type: !20)
+!20 = !DIDerivedType(tag: DW_TAG_typedef, name: "FOO", scope: !16, file: !3, line: 2, baseType: !10)
+!21 = !DIExpression()
+!22 = !DILocation(line: 4, column: 7, scope: !16)
+!23 = !DILocation(line: 5, column: 1, scope: !16)
+!24 = distinct !DISubprogram(name: "g", linkageName: "\01?g@@YAMPAUS@@@Z", scope: !3, file: !3, line: 14, type: !25, isLocal: false, isDefinition: true, scopeLine: 14, flags: DIFlagPrototyped, isOptimized: false, unit: !2, variables: !4)
+!25 = !DISubroutineType(types: !26)
+!26 = !{!27, !28}
+!27 = !DIBasicType(name: "float", size: 32, encoding: DW_ATE_float)
+!28 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !29, size: 32)
+!29 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "S", file: !3, line: 7, size: 32, elements: !30, identifier: ".?AUS@@")
+!30 = !{!31, !32, !33, !34, !35}
+!31 = !DIDerivedType(tag: DW_TAG_typedef, name: "SREF", scope: !29, file: !3, line: 8, baseType: !10)
+!32 = !DIDerivedType(tag: DW_TAG_typedef, name: "UREF", scope: !29, file: !3, line: 9, baseType: !10)
+!33 = !DIDerivedType(tag: DW_TAG_typedef, name: "RREF", scope: !29, file: !3, line: 10, baseType: !27)
+!34 = !DIDerivedType(tag: DW_TAG_member, name: "x", scope: !29, file: !3, line: 12, baseType: !31, size: 32)
+!35 = !DISubprogram(name: "foo", linkageName: "\01?foo@S@@QAEMXZ", scope: !29, file: !3, line: 11, type: !36, isLocal: false, isDefinition: false, scopeLine: 11, flags: DIFlagPrototyped, isOptimized: false)
+!36 = !DISubroutineType(cc: DW_CC_BORLAND_thiscall, types: !37)
+!37 = !{!33, !38}
+!38 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !29, size: 32, flags: DIFlagArtificial | DIFlagObjectPointer)
+!39 = !DILocalVariable(name: "s", arg: 1, scope: !24, file: !3, line: 14, type: !28)
+!40 = !DILocation(line: 14, column: 12, scope: !24)
+!41 = !DILocalVariable(name: "p", scope: !24, file: !3, line: 15, type: !42)
+!42 = distinct !DICompositeType(tag: DW_TAG_union_type, name: "pun", scope: !24, file: !3, line: 15, size: 32, elements: !43)
+!43 = !{!44, !45}
+!44 = !DIDerivedType(tag: DW_TAG_member, name: "x", scope: !42, file: !3, line: 15, baseType: !10, size: 32)
+!45 = !DIDerivedType(tag: DW_TAG_member, name: "f", scope: !42, file: !3, line: 15, baseType: !27, size: 32)
+!46 = !DILocation(line: 15, column: 33, scope: !24)
+!47 = !DILocation(line: 16, column: 9, scope: !24)
+!48 = !DILocation(line: 16, column: 12, scope: !24)
+!49 = !DILocation(line: 16, column: 5, scope: !24)
+!50 = !DILocation(line: 16, column: 7, scope: !24)
+!51 = !DILocation(line: 17, column: 12, scope: !24)
+!52 = !DILocation(line: 17, column: 16, scope: !24)
+!53 = !DILocation(line: 17, column: 19, scope: !24)
+!54 = !DILocation(line: 17, column: 14, scope: !24)
+!55 = !DILocation(line: 17, column: 3, scope: !24)
+!56 = distinct !DISubprogram(name: "foo", linkageName: "\01?foo@S@@QAEMXZ", scope: !29, file: !3, line: 11, type: !36, isLocal: false, isDefinition: true, scopeLine: 11, flags: DIFlagPrototyped, isOptimized: false, unit: !2, declaration: !35, variables: !4)
+!57 = !DILocalVariable(name: "this", arg: 1, scope: !56, type: !28, flags: DIFlagArtificial | DIFlagObjectPointer)
+!58 = !DILocation(line: 0, scope: !56)
+!59 = !DILocation(line: 11, column: 16, scope: !56)
+!60 = distinct !DISubprogram(name: "h", linkageName: "\01?h@@YAXPAUW@@@Z", scope: !3, file: !3, line: 35, type: !61, isLocal: false, isDefinition: true, scopeLine: 35, flags: DIFlagPrototyped, isOptimized: false, unit: !2, variables: !4)
+!61 = !DISubroutineType(types: !62)
+!62 = !{null, !63}
+!63 = !DIDerivedType(tag: DW_TAG_typedef, name: "PTR", file: !3, line: 34, baseType: !64)
+!64 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !65, size: 32)
+!65 = !DICompositeType(tag: DW_TAG_structure_type, name: "W", file: !3, line: 30, flags: DIFlagFwdDecl, identifier: ".?AUW@@")
+!66 = !DILocalVariable(name: "p", arg: 1, scope: !60, file: !3, line: 35, type: !63)
+!67 = !DILocation(line: 35, column: 12, scope: !60)
+!68 = !DILocation(line: 35, column: 16, scope: !60)