DebugInfo: elide type index entries for synthetic types

Compiler emitted synthetic types may not have an associated DIFile
(translation unit).  In such a case, when generating CodeView debug type
information, we would attempt to compute an absolute filepath which
would result in a segfault due to a NULL DIFile*.  If there is no source
file associated with the type, elide the type index entry for the type
and record the type information.  This actually results in higher
fidelity debug information than clang/C2 as of this writing.

Resolves PR32668!

llvm-svn: 302085

diff --git a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
index 786b116..28fa782 100644 (file)
--- a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
@@ -1705,10 +1705,12 @@ TypeIndex CodeViewDebug::lowerCompleteTypeClass(const DICompositeType *Ty) {
                  SizeInBytes, FullName, Ty->getIdentifier());
   TypeIndex ClassTI = TypeTable.writeKnownType(CR);
 
-  StringIdRecord SIDR(TypeIndex(0x0), getFullFilepath(Ty->getFile()));
-  TypeIndex SIDI = TypeTable.writeKnownType(SIDR);
-  UdtSourceLineRecord USLR(ClassTI, SIDI, Ty->getLine());
-  TypeTable.writeKnownType(USLR);
+  if (const auto *File = Ty->getFile()) {
+    StringIdRecord SIDR(TypeIndex(0x0), getFullFilepath(File));
+    TypeIndex SIDI = TypeTable.writeKnownType(SIDR);
+    UdtSourceLineRecord USLR(ClassTI, SIDI, Ty->getLine());
+    TypeTable.writeKnownType(USLR);
+  }
 
   addToUDTs(Ty, ClassTI);
 

diff --git a/llvm/test/DebugInfo/COFF/synthetic.ll b/llvm/test/DebugInfo/COFF/synthetic.ll
new file mode 100644 (file)
index 0000000..7a2f3b8
--- /dev/null
+++ b/llvm/test/DebugInfo/COFF/synthetic.ll
@@ -0,0 +1,55 @@
+; RUN: llc -mtriple x86_64-unknown-windows-msvc -filetype asm -o - %s | FileCheck %s
+
+target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-windows-msvc"
+
+define dllexport void ()* @f() !dbg !6 {
+entry:
+  ret void ()* null, !dbg !28
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
+!1 = !DIFile(filename: "<stdin>", directory: "/Users/compnerd/Source/llvm", checksumkind: CSK_MD5, checksum: "2851eea4f12e754f1a68c47a7045406a")
+!2 = !{}
+!3 = !{i32 2, !"CodeView", i32 1}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!6 = distinct !DISubprogram(name: "f", scope: !1, file: !1, line: 1, type: !7, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: false, unit: !0, variables: !2)
+!7 = !DISubroutineType(types: !8)
+!8 = !{!9}
+!9 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !10, size: 64)
+!10 = !DICompositeType(tag: DW_TAG_structure_type, scope: !1, size: 256, flags: DIFlagAppleBlock, elements: !11)
+!11 = !{!12, !14, !16, !17, !21}
+!12 = !DIDerivedType(tag: DW_TAG_member, name: "__isa", scope: !1, file: !1, baseType: !13, size: 64)
+!13 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 64)
+!14 = !DIDerivedType(tag: DW_TAG_member, name: "__flags", scope: !1, file: !1, baseType: !15, size: 32, offset: 64)
+!15 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!16 = !DIDerivedType(tag: DW_TAG_member, name: "__reserved", scope: !1, file: !1, baseType: !15, size: 32, offset: 96)
+!17 = !DIDerivedType(tag: DW_TAG_member, name: "__FuncPtr", scope: !1, file: !1, baseType: !18, size: 64, offset: 128)
+!18 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !19, size: 64)
+!19 = !DISubroutineType(types: !20)
+!20 = !{null}
+!21 = !DIDerivedType(tag: DW_TAG_member, name: "__descriptor", scope: !1, baseType: !22, size: 64, align: 64, offset: 192)
+!22 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !23, size: 64)
+!23 = !DICompositeType(tag: DW_TAG_structure_type, name: "__block_descriptor", scope: !1, size: 64, flags: DIFlagAppleBlock, elements: !24)
+!24 = !{!25, !27}
+!25 = !DIDerivedType(tag: DW_TAG_member, name: "reserved", scope: !1, file: !1, baseType: !26, size: 32)
+!26 = !DIBasicType(name: "long unsigned int", size: 32, encoding: DW_ATE_unsigned)
+!27 = !DIDerivedType(tag: DW_TAG_member, name: "Size", scope: !1, file: !1, baseType: !26, size: 32, offset: 32)
+!28 = !DILocation(line: 1, scope: !6)
+
+; CHECK: # Struct
+; CHECK: #   TypeLeafKind: LF_STRUCTURE
+; CHECK: #   MemberCount: 0
+; CHECK: #   Properties [
+; CHECK: #     ForwardReference
+; CHECK: #   ]
+; CHECK: #   FieldList: 0x0
+; CHECK: #   DerivedFrom: 0x0
+; CHECK: #   VShape: 0x0
+; CHECK: #   SizeOf: 0
+; CHECK: #   Name: __block_descriptor
+; CHECK: # }
+