Add support for DW_TAG_thrown_type.

For Swift we would like to be able to encode the error types that a
function may throw, so the debugger can display them alongside the
function's return value when finish-ing a function.

DWARF defines DW_TAG_thrown_type (intended to be used for C++ throw()
declarations) that is a perfect fit for this purpose. This patch wires
up support for DW_TAG_thrown_type in LLVM by adding a list of thrown
types to DISubprogram.

To offset the cost of the extra pointer, there is a follow-up patch
that turns DISubprogram into a variable-length node.

rdar://problem/29481673

Differential Revision: https://reviews.llvm.org/D32559

llvm-svn: 301489

3 files changed, 72 insertions, 4 deletions

diff --git a/llvm/test/Assembler/disubprogram.ll b/llvm/test/Assembler/disubprogram.ll
index f6352a5e82c..8a3a60aa079 100644
--- a/llvm/test/Assembler/disubprogram.ll
+++ b/llvm/test/Assembler/disubprogram.ll
@@ -6,8 +6,8 @@ define void @_Z3foov() !dbg !9 {
   ret void
 }
 
-; CHECK: !named = !{!0, !1, !2, !3, !4, !5, !6, !7, !8, !9, !10, !11, !12}
-!named = !{!0, !1, !2, !3, !4, !5, !6, !7, !8, !9, !10, !11, !12}
+; CHECK: !named = !{!0, !1, !2, !3, !4, !5, !6, !7, !8, !9, !10, !11, !12, !13, !14}
+!named = !{!0, !1, !2, !3, !4, !5, !6, !7, !8, !9, !10, !11, !12, !13, !14}
 
 !0 = !{null}
 !1 = distinct !DICompositeType(tag: DW_TAG_structure_type)
@@ -61,6 +61,14 @@ define void @_Z3foov() !dbg !9 {
                             unit: !8,
                             templateParams: !5, declaration: !9, variables: !6)
 
-!13 = !{i32 1, !"Debug Info Version", i32 3}
-!llvm.module.flags = !{!13}
+!13 = !{!4}
+; CHECK: !13 = !{!4}
+; CHECK: !14 = distinct !DISubprogram(name: "foo", scope: !1, file: !2, line: 1, type: !3, isLocal: true, isDefinition: true, scopeLine: 2, isOptimized: false, unit: !8, thrownTypes: !13)
+!14 = distinct !DISubprogram(name: "foo", scope: !1,
+                            file: !2, line: 1, type: !3, isLocal: true,
+                            isDefinition: true, scopeLine: 2, isOptimized: false,
+                            unit: !8, thrownTypes: !13)
+
+!15 = !{i32 1, !"Debug Info Version", i32 3}
+!llvm.module.flags = !{!15}
 !llvm.dbg.cu = !{!8}
diff --git a/llvm/test/DebugInfo/Generic/thrownTypes.ll b/llvm/test/DebugInfo/Generic/thrownTypes.ll
new file mode 100644
index 00000000000..8e84e7bf2bf
--- /dev/null
+++ b/llvm/test/DebugInfo/Generic/thrownTypes.ll
@@ -0,0 +1,38 @@
+; REQUIRES: object-emission
+
+; RUN: %llc_dwarf -O0 -filetype=obj < %s | llvm-dwarfdump -debug-dump=info - | FileCheck %s
+
+; CHECK: DW_TAG_subprogram
+; CHECK:   DW_AT_name {{.*}} "f"
+; CHECK-NOT: DW_TAG
+; CHECK:   DW_TAG_thrown_type
+; CHECK-NEXT:   DW_AT_type {{.*}} {[[ERROR:.*]]}
+; CHECK-NOT: DW_TAG
+; CHECK:   DW_TAG_thrown_type
+; CHECK-NEXT:   DW_AT_type {{.*}} {[[ERROR2:.*]]}
+; CHECK: [[ERROR]]: DW_TAG_structure_type
+; CHECK-NEXT:   DW_AT_name {{.*}} "Error"
+; CHECK: [[ERROR2]]: DW_TAG_structure_type
+; CHECK-NEXT:   DW_AT_name {{.*}} "DifferentError"
+
+; Function Attrs: nounwind uwtable
+define void @f() #0 !dbg !5 {
+entry:
+  ret void, !dbg !11
+}
+
+attributes #0 = { nounwind uwtable }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!8, !9}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_Swift, producer: "swiftc", isOptimized: false, emissionKind: FullDebug, file: !1)
+!1 = !DIFile(filename: "f.swift", directory: "/")
+!3 = !DICompositeType(tag: DW_TAG_structure_type, name: "Error")
+!4 = !DICompositeType(tag: DW_TAG_structure_type, name: "DifferentError")
+!5 = distinct !DISubprogram(name: "f", line: 2, isLocal: false, isDefinition: true, unit: !0, scopeLine: 2, file: !1, scope: !1, type: !6, thrownTypes: !{!3, !4})
+!6 = !DISubroutineType(types: !7)
+!7 = !{null}
+!8 = !{i32 2, !"Dwarf Version", i32 4}
+!9 = !{i32 1, !"Debug Info Version", i32 3}
+!11 = !DILocation(line: 3, scope: !5)
diff --git a/llvm/test/Verifier/DISubprogram.ll b/llvm/test/Verifier/DISubprogram.ll
new file mode 100644
index 00000000000..e78220c8bd7
--- /dev/null
+++ b/llvm/test/Verifier/DISubprogram.ll
@@ -0,0 +1,22 @@
+; RUN: not opt -S <%s 2>&1| FileCheck %s
+
+define void @f() !dbg !14 {
+  ret void
+}
+
+!0 = !{null}
+!1 = distinct !DICompositeType(tag: DW_TAG_structure_type)
+!2 = !DIFile(filename: "path/to/file", directory: "/path/to/dir")
+!3 = !DISubroutineType(types: !0)
+!4 = distinct !DICompositeType(tag: DW_TAG_structure_type)
+!8 = distinct !DICompileUnit(language: DW_LANG_Swift, producer: "clang",
+                             file: !2, emissionKind: 2)
+; CHECK: invalid thrown type
+!13 = !{!14}
+!14 = distinct !DISubprogram(name: "f", scope: !1,
+                            file: !2, line: 1, type: !3, isLocal: true,
+                            isDefinition: true, scopeLine: 2,
+                            unit: !8, thrownTypes: !13)
+!15 = !{i32 1, !"Debug Info Version", i32 3}
+!llvm.module.flags = !{!15}
+!llvm.dbg.cu = !{!8}