From c33c447af94922d68fd25fe666a077c3a56b2102 Mon Sep 17 00:00:00 2001
From: Peter Collingbourne <peter@pcc.me.uk>
Date: Wed, 25 Mar 2015 17:44:49 +0000
Subject: [PATCH] DebugInfo: Permit DW_TAG_structure_type, DW_TAG_member,
 DW_TAG_typedef tags with empty file names.

Some languages, such as Go, have pre-defined structure types (e.g. "string"
is essentially a pointer/length pair) or pre-defined "typedef" types
(e.g. "error" is essentially a typedef for a specific interface type).
Such types do not have associated source location, so a Go frontend would
be correct not to associate a file name with such types.

This change relaxes the DIType verifier to permit unlocated types with
these tags.

Differential Revision: http://reviews.llvm.org/D8588

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233200 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/IR/DebugInfo.cpp                    |  4 +-
 test/DebugInfo/X86/missing-file-line.ll | 61 +++++++++++++++++++++++++
 2 files changed, 64 insertions(+), 1 deletion(-)
 create mode 100644 test/DebugInfo/X86/missing-file-line.ll

diff --git a/lib/IR/DebugInfo.cpp b/lib/IR/DebugInfo.cpp
index ad0b98e90c0..9a6b9536bc1 100644
--- a/lib/IR/DebugInfo.cpp
+++ b/lib/IR/DebugInfo.cpp
@@ -283,7 +283,9 @@ bool DIType::Verify() const {
         Tag != dwarf::DW_TAG_restrict_type && Tag != dwarf::DW_TAG_array_type &&
         Tag != dwarf::DW_TAG_enumeration_type &&
         Tag != dwarf::DW_TAG_subroutine_type &&
-        Tag != dwarf::DW_TAG_inheritance && Tag != dwarf::DW_TAG_friend)
+        Tag != dwarf::DW_TAG_inheritance && Tag != dwarf::DW_TAG_friend &&
+        Tag != dwarf::DW_TAG_structure_type && Tag != dwarf::DW_TAG_member &&
+        Tag != dwarf::DW_TAG_typedef)
       return false;
   }
 
diff --git a/test/DebugInfo/X86/missing-file-line.ll b/test/DebugInfo/X86/missing-file-line.ll
new file mode 100644
index 00000000000..2e84b8affeb
--- /dev/null
+++ b/test/DebugInfo/X86/missing-file-line.ll
@@ -0,0 +1,61 @@
+; REQUIRES: object-emission
+
+; RUN: llc -mtriple=x86_64-linux-gnu -filetype=obj %s -o - | llvm-dwarfdump -debug-dump=all - > %t
+; RUN: FileCheck --check-prefix=CHECK1 %s < %t
+; RUN: FileCheck --check-prefix=CHECK2 %s < %t
+; RUN: FileCheck --check-prefix=CHECK3 %s < %t
+
+; Test that we accept and generate DWARF entities for DW_TAG_structure_type,
+; DW_TAG_member and DW_TAG_typedef with no source location. These can come up
+; in some languages with predefined types.
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+%struct.S = type { %struct.S* }
+
+define void @f() {
+  %x = alloca %struct.S, align 8
+  ; CHECK1: DW_TAG_structure_type
+  ; CHECK1-NOT: DW_AT_decl_file
+  ; CHECK1-NOT: DW_AT_decl_line
+  ; CHECK1: {{DW_TAG|NULL}}
+
+  ; CHECK2: DW_TAG_member
+  ; CHECK2-NOT: DW_AT_decl_file
+  ; CHECK2-NOT: DW_AT_decl_line
+  ; CHECK2: {{DW_TAG|NULL}}
+
+  ; CHECK3: DW_TAG_typedef
+  ; CHECK3-NOT: DW_AT_decl_file
+  ; CHECK3-NOT: DW_AT_decl_line
+  ; CHECK3: {{DW_TAG|NULL}}
+  call void @llvm.dbg.declare(metadata %struct.S* %x, metadata !10, metadata !16), !dbg !17
+  ret void, !dbg !18
+}
+
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!7, !8}
+!llvm.ident = !{!9}
+
+!0 = !MDCompileUnit(language: DW_LANG_C99, file: !1, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: 1, enums: !2, retainedTypes: !2, subprograms: !3, globals: !2, imports: !2)
+!1 = !MDFile(filename: "file.c", directory: "/dir")
+!2 = !{}
+!3 = !{!4}
+!4 = !MDSubprogram(name: "f", scope: !1, file: !1, line: 7, type: !5, isLocal: false, isDefinition: true, scopeLine: 7, isOptimized: false, function: void ()* @f, variables: !2)
+!5 = !MDSubroutineType(types: !6)
+!6 = !{null}
+!7 = !{i32 2, !"Dwarf Version", i32 4}
+!8 = !{i32 2, !"Debug Info Version", i32 3}
+!9 = !{!"clang"}
+!10 = !MDLocalVariable(tag: DW_TAG_auto_variable, name: "x", scope: !4, file: !1, line: 8, type: !11)
+!11 = !MDDerivedType(tag: DW_TAG_typedef, name: "SS", baseType: !12)
+!12 = !MDCompositeType(tag: DW_TAG_structure_type, name: "S", size: 64, align: 64, elements: !13)
+!13 = !{!14}
+!14 = !MDDerivedType(tag: DW_TAG_member, name: "s", scope: !12, baseType: !15, size: 64, align: 64)
+!15 = !MDDerivedType(tag: DW_TAG_pointer_type, baseType: !12, size: 64, align: 64)
+!16 = !MDExpression()
+!17 = !MDLocation(line: 8, column: 6, scope: !4)
+!18 = !MDLocation(line: 9, column: 1, scope: !4)
-- 
2.34.1