[Dwarf-Discuss] armcc DWARF

[David Anderson]

On 05/22/2018 04:18 PM, Michael Eager wrote:
> On 05/22/2018 02:33 PM, David Anderson via Dwarf-Discuss wrote:
>>
>> I have been given a tiny object file? created by armcc
>> using DWARF and things make no sense to me so far.
>>
>> dwarfdump (and libdwarf) use the SHT_GROUP section data to associate
>> sections to their group.? This is a .o, not a fully linked executable or
>> shared-library.
>>
>> (libdwarf assigns group numbers itself. group 1 is? non-dwo .debug
>> sections)
>> (any .dwo sections present would be shown as group 2
>> if not listed in a section-group header, but no such are present here)
>>
>>
> Can you post the output of readelf?
>
Section Headers:
? [Nr] Name????????????? Type??????????? Addr???? Off??? Size?? ES Flg
Lk Inf Al
? [ 0]?????????????????? NULL??????????? 00000000 000000 000000 00?????
0?? 0? 0
? [ 1] .text???????????? PROGBITS??????? 00000000 000034 000008 00? AX?
0?? 0? 4
? [ 2] .arm_vfe_header?? PROGBITS??????? 00000000 00003c 000004 00?????
0?? 0? 4
? [ 3] .comment????????? PROGBITS??????? 00000000 000040 00007a 00?????
0?? 0? 1
? [ 4] .debug_frame????? PROGBITS??????? 00000000 0000ba 000044 00?????
0?? 0? 1
? [ 5] .debug_info?????? PROGBITS??????? 00000000 0000fe 000098 00?????
0?? 0? 1
? [ 6] .debug_info?????? PROGBITS??????? 00000000 000196 0000e0 00???????
? [ 7] .debug_line?????? PROGBITS??????? 00000000 000276 00002c 00?????
0?? 0? 1
? [ 8] .debug_line?????? PROGBITS??????? 00000000 0002a2 000038 00?????
0?? 0? 1
? [ 9] .debug_loc??????? PROGBITS??????? 00000000 0002da 000050 00?????
0?? 0? 1
? [10] .debug_macinfo??? PROGBITS??????? 00000000 00032a 0002cc 00?????
0?? 0? 1
? [11] .debug_pubnames?? PROGBITS??????? 00000000 0005f6 000020 00?????
0?? 0? 1
? [12] __ARM_grp.a.h.2_sq0000_$0QbXG$5KW3_200000 GROUP??????????
00000000 000618 00000c 04???? 23? 17? 4
? [13] .debug_info?????? PROGBITS??????? 00000000 000624 0000a8 00?? G?
0?? 0? 1
? [14] .debug_line?????? PROGBITS??????? 00000000 0006cc 000028 00?? G?
0?? 0? 1
? [15] __ARM_grp.b.h.2_ws0000_eYI6SD7WPJ9_500000 GROUP??????????
00000000 0006f4 000008 04???? 23? 18? 4
? [16] .debug_info?????? PROGBITS??????? 00000000 0006fc 0000ac 00?? G?
0?? 0? 1
? [17] __ARM_grp.test.c.2_cx0000_sjeCPPJ9rd8_900000 GROUP??????????
00000000 0007a8 000010 04???? 23? 19? 4
? [18] .debug_info?????? PROGBITS??????? 00000000 0007b8 00009c 00?? G?
0?? 0? 1
? [19] .debug_line?????? PROGBITS??????? 00000000 000854 000038 00?? G?
0?? 0? 1
? [20] .debug_macinfo??? PROGBITS??????? 00000000 00088c 000010 00?? G?
0?? 0? 1
? [21] __ARM_grp..debug_abbrev.group.2_Am0000_lbphKItke$2_000000
GROUP?????????? 00000000 00089c 000008 04???? 23? 13? 4
? [22] .debug_abbrev???? PROGBITS??????? 00000000 0008a4 0005a4 00?? G?
0?? 0? 1
? [23] .symtab?????????? SYMTAB????????? 00000000 000e48 000190 10????
33? 13? 4
? [24] .rel.debug_frame? REL???????????? 00000000 000fd8 000010 08????
23?? 4? 4
? [25] .rel.debug_info?? REL???????????? 00000000 000fe8 000018 08????
23?? 5? 4
? [26] .rel.debug_info?? REL???????????? 00000000 001000 000068 08????
23?? 6? 4
? [27] .rel.debug_line?? REL???????????? 00000000 001068 000008 08????
23?? 8? 4
? [28] .rel.debug_pubnames REL???????????? 00000000 001070 000008 08????
23? 11? 4
? [29] .rel.debug_info?? REL???????????? 00000000 001078 000010 08????
23? 13? 4
? [30] .rel.debug_info?? REL???????????? 00000000 001088 000018 08????
23? 16? 4
? [31] .rel.debug_info?? REL???????????? 00000000 0010a0 000020 08????
23? 18? 4
? [32] .shstrtab???????? STRTAB????????? 00000000 0010c0 000172 00?????
0?? 0? 1
? [33] .strtab?????????? STRTAB????????? 00000000 001232 00037e 00?????
0?? 0? 1
? [34] .ARM.attributes?? ARM_ATTRIBUTES? 00000000 0015b0 000045 00?????
0?? 0? 1


I'll email you? the test case object file, Mike, so you can see the
group records etc.

Here is the test source:
#include "a.h"
#include "b.h"

void set_point(struct POINT *point, NUMBER x, NUMBER y)
{
??? point->x = x;
??? point->y = y;
}


q3 1708: cat a.h
typedef float NUMBER;
q3 1709: cat b.h
struct POINT {
??? NUMBER x;
??? NUMBER y;
};


DavidA.

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