[llvm] r302085 - DebugInfo: elide type index entries for synthetic types

[Saleem Abdulrasool via llvm-commits]

Author: compnerd
Date: Wed May  3 16:39:01 2017
New Revision: 302085

URL: http://llvm.org/viewvc/llvm-project?rev=302085&view=rev
Log:
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!

Added:
    llvm/trunk/test/DebugInfo/COFF/synthetic.ll
Modified:
    llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp?rev=302085&r1=302084&r2=302085&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp Wed May  3 16:39:01 2017
@@ -1705,10 +1705,12 @@ TypeIndex CodeViewDebug::lowerCompleteTy
                  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);
 

Added: llvm/trunk/test/DebugInfo/COFF/synthetic.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/COFF/synthetic.ll?rev=302085&view=auto
==============================================================================
--- llvm/trunk/test/DebugInfo/COFF/synthetic.ll (added)
+++ llvm/trunk/test/DebugInfo/COFF/synthetic.ll Wed May  3 16:39:01 2017
@@ -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: # }
+