[PING^3][PATCH][gdb/symtab] Handle gas-generated stabs with -fPIE/-pie

[Tom de Vries]

On 06-09-19 17:31, Tom de Vries wrote:
> On 29-08-19 17:04, Tom de Vries wrote:
>> On 16-08-19 17:57, Tom de Vries wrote:
>>> Hi,
>>>
>>> With gdb.dwarf2/dw2-ranges.exp and target board unix/-fPIE/-pie, we run into:
>>> ...
>>> info line main3^M
>>> No line number information available for address 0x55555555464c <main3>^M
>>> (gdb) FAIL: gdb.dwarf2/dw2-ranges.exp: info line main3
>>> ...
>>>
>>> The main3 function in the executable comes from dw2-ranges3.o, which is
>>> generated like this (leaving out -fPIE -pie for clarity):
>>> ...
>>> $ gcc -S dw2-ranges3.c
>>> $ gcc dw2-ranges3.s -o dw2-ranges3.o -gstabs
>>> ...
>>> So, main3 is described in stabs format, generated by gas.
>>>
>>> The difference between gcc-generated and gas-generated SLINE stabs is that gcc
>>> generates a sequence SO (source), FUN (function), SLINE (source line) whereas
>>> gas generates SO, SLINE.
>>>
>>> The problem is that the line address relocation handling in process_one_symbol
>>> assumes an order of SO, FUN, SLINE.
>>>
>>> Fix this by also handling SO, SLINE.
>>>
>>> This also fixes FAILs in gdb.btrace/instruction_history.exp with
>>> target board stabs/-fPIE/-pie.
>>>
>>> Tested on x86_64-linux with target boards unix, unix/-fPIE/-pie, stabs, and
>>> stabs/-fPIE/-pie.
>>>
>>> OK for trunk?
>>>

Ping^3.

Thanks,
- Tom

>>> [gdb/symtab] Handle gas-generated stabs with -fPIE/-pie
>>>
>>> gdb/ChangeLog:
>>>
>>> 2019-08-16  Tom de Vries  <tdevries@suse.de>
>>>
>>> 	PR symtab/12497
>>> 	* dbxread.c (process_one_symbol): Handle relocation of SLINE address
>>> 	without preceding FUN/FNAME.
>>>
>>> ---
>>>  gdb/dbxread.c | 3 +++
>>>  1 file changed, 3 insertions(+)
>>>
>>> diff --git a/gdb/dbxread.c b/gdb/dbxread.c
>>> index e339d1f7ec..e0ab4ec19c 100644
>>> --- a/gdb/dbxread.c
>>> +++ b/gdb/dbxread.c
>>> @@ -2626,6 +2626,9 @@ process_one_symbol (int type, int desc, CORE_ADDR valu, const char *name,
>>>  
>>>        /* Relocate for dynamic loading and for ELF acc
>>>           function-relative symbols.  */
>>> +      if (function_start_offset == 0)
>>> +	function_start_offset
>>> +	  = ANOFFSET (section_offsets, SECT_OFF_TEXT (objfile));
>>>        valu += function_start_offset;
>>>  
>>>        /* GCC 2.95.3 emits the first N_SLINE stab somwehere in the
>>>