Re: GDB internal error in pc_in_thread_step_range

[Simon Marchi <simon.marchi@polymtl.ca>]

On 2018-12-23 10:23 a.m., Eli Zaretskii wrote:
>> Date: Sun, 23 Dec 2018 09:35:02 +0400
>> From: Joel Brobecker <brobecker@adacore.com>
>> Cc: Eli Zaretskii <eliz@gnu.org>, gdb-patches@sourceware.org
>>
>>>>> Side-question, are there some debug symbols in the binary that could
>>>>> describe this location?
>>>>
>>>> How do I know that?
>>>
>>> I would normally use "readelf --debug-dump" to look at the DWARF info, but
>>> since this is not an ELF, I don't know.
>>
>> Objdump has the same kind of functionality for both DWARF and
>> the symbol table (--dwarf, -t, -T, etc).
> 
> Yes.  But in what part of its output would you expect to see debug
> symbols that describe this location?
> 

If you use "objdump --dwarf=info <binary>", then you can see some nodes representing
subprograms (functions), like this:

 <1><51>: Abbrev Number: 5 (DW_TAG_subprogram)
    <52>   DW_AT_external    : 1
    <52>   DW_AT_name        : (indirect string, offset: 0x257b): main
    <56>   DW_AT_decl_file   : 1
    <57>   DW_AT_decl_line   : 6
    <58>   DW_AT_decl_column : 5
    <59>   DW_AT_type        : <0x4a>
    <5d>   DW_AT_low_pc      : 0x1119
    <65>   DW_AT_high_pc     : 0xb
    <6d>   DW_AT_frame_base  : 1 byte block: 9c 	(DW_OP_call_frame_cfa)
    <6f>   DW_AT_GNU_all_call_sites: 1


Here, DW_AT_high_pc is actually an offset relative to DW_AT_low_pc. This means
my function main's range is [0x1119,0x1119+0xb[.  So you could search in that
output for "__mingw_CRTStartup", to see if there's a node describing that function.

Honestly, I would be quite surprised if you had DWARF info for it but not a basic
COFF symbol, but it costs nothing to check.

Simon