[LLVM] Create lf_alias nodes for typedef and using

llvm/include/llvm/DebugInfo/CodeView/CodeViewTypes.def

@@ -53,6 +53,7 @@ TYPE_RECORD(LF_ENUM, 0x1507, Enum)
 TYPE_RECORD(LF_TYPESERVER2, 0x1515, TypeServer2)
 TYPE_RECORD(LF_VFTABLE, 0x151d, VFTable)
 TYPE_RECORD(LF_VTSHAPE, 0x000a, VFTableShape)
+TYPE_RECORD(LF_ALIAS, 0x150a, Alias)
 
 TYPE_RECORD(LF_BITFIELD, 0x1205, BitField)
 
@@ -181,7 +182,6 @@ CV_TYPE(LF_MANAGED_ST, 0x140f)
 CV_TYPE(LF_ST_MAX, 0x1500)
 CV_TYPE(LF_TYPESERVER, 0x1501)
 CV_TYPE(LF_DIMARRAY, 0x1508)
-CV_TYPE(LF_ALIAS, 0x150a)
 CV_TYPE(LF_DEFARG, 0x150b)
 CV_TYPE(LF_FRIENDFCN, 0x150c)
 CV_TYPE(LF_NESTTYPEEX, 0x1512)

llvm/include/llvm/DebugInfo/CodeView/TypeRecord.h

@@ -952,6 +952,18 @@ class EndPrecompRecord : public TypeRecord {
   uint32_t Signature = 0;
 };
 
+// LF_ALIAS
+class AliasRecord : public TypeRecord {
+public:
+  AliasRecord() = default;
+  explicit AliasRecord(TypeRecordKind Kind) : TypeRecord(Kind) {}
+  AliasRecord(TypeIndex UnderlyingType, StringRef Name)
+      : TypeRecord(TypeRecordKind::Alias), UnderlyingType(UnderlyingType), Name(Name) {}
+
+  TypeIndex UnderlyingType;
+  StringRef Name;
+};
+
 } // end namespace codeview
 } // end namespace llvm
 

llvm/include/llvm/DebugInfo/LogicalView/Readers/LVCodeViewVisitor.h

@@ -418,6 +418,8 @@ class LVLogicalVisitor final {
                          LVElement *Element);
   Error visitKnownRecord(CVType &Record, EndPrecompRecord &EndPrecomp,
                          TypeIndex TI, LVElement *Element);
+  Error visitKnownRecord(CVType &Record, AliasRecord &Alias,
+                         TypeIndex TI, LVElement *Element);
 
   Error visitUnknownMember(CVMemberRecord &Record, TypeIndex TI);
   Error visitKnownMember(CVMemberRecord &Record, BaseClassRecord &Base,

llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

@@ -1728,14 +1728,17 @@ TypeIndex CodeViewDebug::lowerTypeAlias(const DIDerivedType *Ty) {
 
   addToUDTs(Ty);
 
+  AliasRecord AR(UnderlyingTypeIndex, TypeName);
+  auto AliasIndex = TypeTable.writeLeafType(AR);
+
   if (UnderlyingTypeIndex == TypeIndex(SimpleTypeKind::Int32Long) &&
       TypeName == "HRESULT")
     return TypeIndex(SimpleTypeKind::HResult);
   if (UnderlyingTypeIndex == TypeIndex(SimpleTypeKind::UInt16Short) &&
       TypeName == "wchar_t")
     return TypeIndex(SimpleTypeKind::WideCharacter);
 
-  return UnderlyingTypeIndex;
+  return AliasIndex;
 }
 
 TypeIndex CodeViewDebug::lowerTypeArray(const DICompositeType *Ty) {
@@ -2750,14 +2753,6 @@ TypeIndex CodeViewDebug::getCompleteTypeIndex(const DIType *Ty) {
   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();
-
   // 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()) {

llvm/lib/DebugInfo/CodeView/RecordName.cpp

@@ -251,6 +251,11 @@ Error TypeNameComputer::visitKnownRecord(CVType &CVR,
   return Error::success();
 }
 
+Error TypeNameComputer::visitKnownRecord(CVType &CVR, AliasRecord &Alias) {
+  Name = Alias.Name;
+  return Error::success();
+}
+
 std::string llvm::codeview::computeTypeName(TypeCollection &Types,
                                             TypeIndex Index) {
   TypeNameComputer Computer(Types);

llvm/lib/DebugInfo/CodeView/TypeDumpVisitor.cpp

@@ -568,3 +568,9 @@ Error TypeDumpVisitor::visitKnownRecord(CVType &CVR,
   W->printHex("Signature", EndPrecomp.getSignature());
   return Error::success();
 }
+
+Error TypeDumpVisitor::visitKnownRecord(CVType &CVR, AliasRecord &Alias) {
+  printTypeIndex("UnderlyingType", Alias.UnderlyingType);
+  W->printString("Name", Alias.Name);
+  return Error::success();
+}

llvm/lib/DebugInfo/CodeView/TypeRecordMapping.cpp

@@ -752,3 +752,10 @@ Error TypeRecordMapping::visitKnownRecord(CVType &CVR,
   error(IO.mapInteger(EndPrecomp.Signature, "Signature"));
   return Error::success();
 }
+
+Error TypeRecordMapping::visitKnownRecord(CVType &CVR, AliasRecord &Alias) {
+  error(IO.mapInteger(Alias.UnderlyingType, "UnderlyingType"));
+  error(IO.mapStringZ(Alias.Name, "Name"));
+
+  return Error::success();
+}

llvm/lib/DebugInfo/LogicalView/Readers/LVCodeViewVisitor.cpp

@@ -2623,6 +2623,18 @@ Error LVLogicalVisitor::visitKnownRecord(CVType &Record,
   return Error::success();
 }
 
+// LF_ALIAS (TPI)
+Error LVLogicalVisitor::visitKnownRecord(CVType &Record, AliasRecord &Alias,
+                                         TypeIndex TI, LVElement *Element) {
+  LLVM_DEBUG({
+    printTypeBegin(Record, TI, Element, StreamTPI);
+    printTypeIndex("UnderlyingType", Alias.UnderlyingType, StreamTPI);
+    W.printString("Name", Alias.Name);
+    printTypeEnd(Record);
+  });
+  return Error::success();
+}
+
 Error LVLogicalVisitor::visitUnknownMember(CVMemberRecord &Record,
                                            TypeIndex TI) {
   LLVM_DEBUG({ W.printHex("UnknownMember", unsigned(Record.Kind)); });

llvm/lib/ObjectYAML/CodeViewYAMLTypes.cpp

@@ -614,6 +614,11 @@ template <> void LeafRecordImpl<EndPrecompRecord>::map(IO &IO) {
   IO.mapRequired("Signature", Record.Signature);
 }
 
+template <> void LeafRecordImpl<AliasRecord>::map(IO &IO) {
+  IO.mapRequired("UnderlyingType", Record.UnderlyingType);
+  IO.mapRequired("Name", Record.Name);
+}
+
 template <> void MemberRecordImpl<OneMethodRecord>::map(IO &IO) {
   MappingTraits<OneMethodRecord>::mapping(IO, Record);
 }

llvm/test/DebugInfo/PDB/Inputs/typedef.ll

@@ -0,0 +1,43 @@
+; ModuleID = 'typedef.cpp'
+source_filename = "typedef.cpp"
+target datalayout = "e-m:w-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-windows-msvc19.44.35214"
+
+; Function Attrs: mustprogress noinline norecurse nounwind optnone uwtable
+define dso_local noundef i32 @main() #0 !dbg !14 {
+entry:
+  %retval = alloca i32, align 4
+  %val = alloca i8, align 1
+  %val2 = alloca i64, align 8
+  store i32 0, ptr %retval, align 4
+    #dbg_declare(ptr %val, !19, !DIExpression(), !22)
+  store i8 15, ptr %val, align 1, !dbg !22
+    #dbg_declare(ptr %val2, !23, !DIExpression(), !26)
+  store i64 -1, ptr %val2, align 8, !dbg !26
+  ret i32 0, !dbg !27
+}
+
+attributes #0 = { mustprogress noinline norecurse nounwind optnone uwtable }
+
+!llvm.dbg.cu = !{!2}
+!llvm.module.flags = !{!7, !8}
+!llvm.ident = !{!13}
+
+!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !5, producer: "clang version 22.0.0git (https://github.com/Walnut356/llvm-project.git 0e257f7d7edfcda5655eeaac55d0ffc398e773a2)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None)
+!5 = !DIFile(filename: "typedef.cpp", directory: "llvm-project")
+!7 = !{i32 2, !"CodeView", i32 1}
+!8 = !{i32 2, !"Debug Info Version", i32 3}
+!13 = !{!"clang version 22.0.0git (https://github.com/Walnut356/llvm-project.git 0e257f7d7edfcda5655eeaac55d0ffc398e773a2)"}
+!14 = distinct !DISubprogram(name: "main", scope: !5, file: !5, line: 6, type: !15, scopeLine: 6, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !2)
+!15 = !DISubroutineType(types: !16)
+!16 = !{!17}
+!17 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!19 = !DILocalVariable(name: "val", scope: !14, file: !5, line: 7, type: !20)
+!20 = !DIDerivedType(tag: DW_TAG_typedef, name: "u8", file: !5, line: 3, baseType: !21)
+!21 = !DIBasicType(name: "unsigned char", size: 8, encoding: DW_ATE_unsigned_char)
+!22 = !DILocation(line: 7, scope: !14)
+!23 = !DILocalVariable(name: "val2", scope: !14, file: !5, line: 8, type: !24)
+!24 = !DIDerivedType(tag: DW_TAG_typedef, name: "i64", file: !5, line: 4, baseType: !25)
+!25 = !DIBasicType(name: "long long", size: 64, encoding: DW_ATE_signed)
+!26 = !DILocation(line: 8, scope: !14)
+!27 = !DILocation(line: 10, scope: !14)

llvm/test/DebugInfo/PDB/Inputs/typedef.yaml

@@ -0,0 +1,12 @@
+---
+TpiStream:
+  Records:
+    - Kind:            LF_ALIAS
+      Alias:
+        UnderlyingType:  32
+        Name:            u8
+    - Kind:            LF_ALIAS
+      Alias:
+        UnderlyingType:  19
+        Name:            i64
+...

llvm/test/DebugInfo/PDB/typedef.test

@@ -0,0 +1,62 @@
+Built with clang (22+) because MSVC does not output lf_alias for typedefs
+
+Build typedef.ll with clang -S -emit-llvm -g:
+
+```
+void *__purecall = 0;
+
+typedef unsigned char u8;
+using i64 = long long;
+
+int main() {
+    u8 val = 15;
+    i64 val2 = -1;
+
+    return 0;
+}
+```
+
+RUN: llc -O0 %p/Inputs/typedef.ll --filetype=obj -o %t.obj
+RUN: llvm-pdbutil dump --types %t.obj | FileCheck --check-prefix=OBJTYPE %s
+
+OBJTYPE: 0x1003 | LF_ALIAS [size = 12] alias = u8, underlying type = 0x0020 (unsigned char)
+OBJTYPE-NEXT: 0x1004 | LF_ALIAS [size = 12] alias = i64, underlying type = 0x0013 (__int64)
+
+RUN: llvm-pdbutil dump --symbols %t.obj | FileCheck --check-prefix=OBJSYM %s
+
+OBJSYM: 0 | S_LOCAL [size = 16] `val`
+OBJSYM-NEXT:     type=0x1003 (u8), flags = none
+OBJSYM: 0 | S_LOCAL [size = 16] `val2`
+OBJSYM:     type=0x1004 (i64), flags = none
+OBJSYM: 0 | S_UDT [size = 12] `u8`
+OBJSYM-NEXT:     original type = 0x1003
+OBJSYM-NEXT: 0 | S_UDT [size = 12] `i64`
+OBJSYM-NEXT:     original type = 0x1004
+
+
+typedef.yaml file generated via `clang -fno-rtti -g -O0 typedef.cpp` and `llvm-pdbutil pdb2yaml -tpi-stream`, and then manually
+reduced to only the typedef nodes
+
+RUN: llvm-pdbutil yaml2pdb -pdb=%t.yaml.pdb %p/Inputs/typedef.yaml
+RUN: llvm-pdbutil dump --types %t.yaml.pdb \
+RUN: | FileCheck --check-prefix=TYPES %s
+
+Also check that the YAML output hasn't drifted
+RUN: llvm-pdbutil pdb2yaml -tpi-stream %t.yaml.pdb \
+RUN: | FileCheck --check-prefixes=YAML %s
+
+TYPES:                           Types (TPI Stream)
+TYPES-NEXT:============================================================
+TYPES-NEXT:  Showing 2 records
+TYPES-NEXT:   0x1000 | LF_ALIAS [size = 12] alias = u8, underlying type = 0x0020 (unsigned char)
+TYPES-NEXT:   0x1001 | LF_ALIAS [size = 12] alias = i64, underlying type = 0x0013 (__int64)
+
+
+YAML:         - Kind:            LF_ALIAS
+YAML-NEXT:      Alias:
+YAML-NEXT:        UnderlyingType:  32
+YAML-NEXT:        Name:            u8
+YAML-NEXT:    - Kind:            LF_ALIAS
+YAML-NEXT:      Alias:
+YAML-NEXT:        UnderlyingType:  19
+YAML-NEXT:        Name:            i64

llvm/tools/llvm-pdbutil/MinimalTypeDumper.cpp

@@ -523,6 +523,13 @@ Error MinimalTypeDumpVisitor::visitKnownRecord(CVType &CVR,
   return Error::success();
 }
 
+Error MinimalTypeDumpVisitor::visitKnownRecord(CVType &CVT,
+                                               AliasRecord &Alias) {
+  P.format(" alias = {0}, underlying type = {1}", Alias.Name,
+           Alias.UnderlyingType);
+  return Error::success();
+}
+
 Error MinimalTypeDumpVisitor::visitKnownMember(CVMemberRecord &CVR,
                                                NestedTypeRecord &Nested) {
   P.format(" [name = `{0}`, parent = {1}]", Nested.Name, Nested.Type);