gcc currently generates duplicate debug information for enums declared in
namespaces.
Compile this C++ code with -g:
namespace { enum x { i = 1 }; }
x y;
In the .s file, I see this:
.uleb128 0x3
.string "x"
.byte 0x4
.byte 0x1
.byte 0x1
.byte 0x4
.byte 0x1
.byte 0x1
.uleb128 0x4
.string "i"
.sleb128 1
.uleb128 0x4
.string "i"
.sleb128 1
Note the duplicate size/file/line info, and the duplication of information
about "i".
readelf --debug-dump shows this:
<2><57>: Abbrev Number: 3 (DW_TAG_enumeration_type)
DW_AT_name : x
DW_AT_byte_size : 4
DW_AT_decl_file : 1
DW_AT_decl_line : 1
DW_AT_byte_size : 4
DW_AT_decl_file : 1
DW_AT_decl_line : 1
<3><60>: Abbrev Number: 4 (DW_TAG_enumerator)
DW_AT_name : i
DW_AT_const_value : 1
<3><64>: Abbrev Number: 4 (DW_TAG_enumerator)
DW_AT_name : i
DW_AT_const_value : 1
where we see the same duplication.
This is not a visible problem when using the debugger, because the duplicate
information just tells it the same information it already has. But it probably
makes the debugger a bit slower. And it definitely makes object files larger
than they need to be, which wastes time creating them and space storing them.
I believe the problem arises like this:
gen_type_die calls
declare_in_namespace calls
gen_type_die
emits die via gen_enumeration_type_die
returns
returns
emits die via gen_enumeration_type_die
I don't have a patch for this. I want to record it before I forget about it.
--
Summary: Duplicate debug info for enums in namespaces
Product: gcc
Version: 4.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: debug
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: ian at airs dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26964
