Implement DW_TAG_subrange_type with DW_AT_count rather than DW_AT_upper_bound
This allows proper disambiguation of unbounded arrays and arrays of zero
bound ("struct foo { int x[]; };" and "struct foo { int x[0]; }"). GCC
instead produces an upper bound of -1 in the latter situation, but count
seems tidier. This way lower_bound is provided if it's not the language
default and count is provided if the count is known, otherwise it's
omitted. Simple.
If someone wants to look at rdar://problem/12566646 and see if this
change is acceptable to that bug/fix, that might be helpful (see the
empty-and-one-elem-array.ll test case which cites that radar).
llvm-svn: 218726
diff --git a/llvm/test/DebugInfo/X86/empty-and-one-elem-array.ll b/llvm/test/DebugInfo/X86/empty-and-one-elem-array.ll
index ba438e8..48379ab 100644
--- a/llvm/test/DebugInfo/X86/empty-and-one-elem-array.ll
+++ b/llvm/test/DebugInfo/X86/empty-and-one-elem-array.ll
@@ -25,9 +25,6 @@
declare void @llvm.dbg.declare(metadata, metadata) nounwind readnone
-; An empty array should not have an AT_upper_bound attribute. But an array of 1
-; should.
-
; CHECK: DW_TAG_base_type
; CHECK-NEXT: DW_AT_name [DW_FORM_strp] ( .debug_str[{{.*}}] = "int")
; CHECK-NEXT: DW_AT_encoding [DW_FORM_data1] (DW_ATE_signed)
@@ -46,7 +43,7 @@
; CHECK-NEXT: DW_AT_type [DW_FORM_ref4]
; CHECK: DW_TAG_subrange_type [{{.*}}]
; CHECK-NEXT: DW_AT_type [DW_FORM_ref4]
-; CHECK-NEXT: DW_AT_upper_bound [DW_FORM_data1] (0x00)
+; CHECK-NEXT: DW_AT_count [DW_FORM_data1] (0x01)
; int bar::b[0]:
; CHECK: DW_TAG_structure_type
@@ -59,9 +56,9 @@
; int[0]:
; CHECK: DW_TAG_array_type [{{.*}}] *
; CHECK-NEXT: DW_AT_type [DW_FORM_ref4]
-; CHECK: DW_TAG_subrange_type [11]
+; CHECK: DW_TAG_subrange_type
; CHECK-NEXT: DW_AT_type [DW_FORM_ref4]
-; CHECK-NOT: DW_AT_upper_bound
+; CHECK: DW_AT_count [DW_FORM_data1] (0x00)
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!33}