dwarf2 error(microblaze)

[Michael Eager]

On 06/03/2011 12:18 AM, naga raj wrote:

> Mike,

Please keep discussion which start on gcc-help on the mailing list.
This allows other people to take a look and offer suggestions.

>>>> How are you compiling it?

>> I have copied the steps from my console which are used in executing  memory_test project.
> Invoking: MicroBlaze gcc compiler
> mb-gcc -Wall -O0 -g3 -gdwarf-3 -c -fmessage-length=0
> -I../../memory_tests_bsp_0/microblaze_0/include -mxl-barrel-shift
> -mxl-pattern-compare -mcpu=v8.20.a -mno-xl-soft-mul -MMD -MP
> -MF"src/memorytest.d" -MT"src/memorytest.d" -o"src/memorytest.o"
> "../src/memorytest.c"

What is the command line when you have errors?   This is a compile
which generates Dwarf3, which you say works OK.

>>> The same application is working fine with Dwarf3. I have used
>>> -gdwarf-3 in compilation and now GDN is displaying local variables
>>> correctly.
>>
>> What are the differences in the Dwarf output between compiling with
>> -g and -gdwarf-3?
>
> dwarf2 debugging information:
>      <1><47a>: Abbrev Number: 13 (DW_TAG_subprogram)
>      <47b>    DW_AT_external    : 1
>      <47c>    DW_AT_name        : (indirect string, offset: 0xf4): main
>      <480>    DW_AT_decl_file   : 1
>      <481>    DW_AT_decl_line   : 59
>      <482>    DW_AT_type        :<0x390>
>      <486>    DW_AT_low_pc      : 0x3dc
>      <48a>    DW_AT_high_pc     : 0x490
>      <48e>    DW_AT_frame_base  : 0x2c    (location list)
>      <492>    DW_AT_sibling     :<0x4a3>
>   <2><496>: Abbrev Number: 14 (DW_TAG_variable)
>      <497>    DW_AT_name        : i
>      <499>    DW_AT_decl_file   : 1
>      <49a>    DW_AT_decl_line   : 61
>      <49b>    DW_AT_type        :<0x390>
>      <49f>    DW_AT_location    : 2 byte block: 91 78     (DW_OP_fbreg: -8)

This appears to be different from the Dwarf dump from your email of
06/02/2011.

What is the location list at offset 0x2c in the .debug_loc section:

> dwarf3 debugging information:
>   <1><468>: Abbrev Number: 13 (DW_TAG_subprogram)
>      <469>    DW_AT_external    : 1
>      <46a>    DW_AT_name        : (indirect string, offset: 0xf4): main
>      <46e>    DW_AT_decl_file   : 1
>      <46f>    DW_AT_decl_line   : 59
>      <470>    DW_AT_type        :<0x388>
>      <474>    DW_AT_low_pc      : 0x3dc
>      <478>    DW_AT_high_pc     : 0x490
>      <47c>    DW_AT_frame_base  : 1 byte block: 9c        (DW_OP_call_frame_cfa)
>      <47e>    DW_AT_sibling     :<0x48f>
>   <2><482>: Abbrev Number: 14 (DW_TAG_variable)
>      <483>    DW_AT_name        : i
>      <485>    DW_AT_decl_file   : 1
>      <486>    DW_AT_decl_line   : 61
>      <487>    DW_AT_type        :<0x388>
>      <48b>    DW_AT_location    : 2 byte block: 91 78     (DW_OP_fbreg: -8)


> Please go through the gdb dump:

Like long ELF or DWARF dumps, please don't send long debug logs
where you single step through dozens of statements displaying a
variety of variables.

>    Breakpoint 1, main () at ../src/memorytest.c:62
> 62          i =20;
> (gdb) n
> 63          init_platform();
> (gdb) p i
>
> Breakpoint 1, find_location_expression (baton=0x8c5f1ec,
> locexpr_length=0xbff405ac, pc=1012)
>      at /build/lin/bld_gdb/gdb/gdb/dwarf2loc.c:62

What is the location expression that gdb is trying to parse?

-- 
Michael Eager	 eager@eagercon.com
1960 Park Blvd., Palo Alto, CA 94306  650-325-8077