gdb: use std::vector instead of alloca in core_target::get_core_register_section

  On 2020-01-13 2:40 p.m., Pedro Alves wrote:
> On 1/12/20 8:17 PM, Simon Marchi wrote:
>> -  contents = (char *) alloca (size);
>> -  if (! bfd_get_section_contents (core_bfd, section, contents,
>> +  std::vector<char> contents (size);
>> +  if (! bfd_get_section_contents (core_bfd, section, contents.data (),
>>  				  (file_ptr) 0, size))
>>      {
> 
> gdb::byte_vector

I used std::vector<char> because the original code also used char, and
m_core_vec->core_read_registers also accepts a char * (although I
could/should have used gdb::char_vector anyway).  However, gdb_byte
probably makes more sense here.  I would push the patch below as a fixup
if it looks good to you.

Simon


From 6758886d9f1f0ddce518ffec5269cc440d2fe4f5 Mon Sep 17 00:00:00 2001
From: Simon Marchi <simon.marchi@efficios.com>
Date: Mon, 13 Jan 2020 14:57:38 -0500
Subject: [PATCH] gdb: use gdb::byte_vector instead of std::vector<char> in
 core_target::get_core_register_section

Since the data held by the `contents` variable is arbitrary binary data,
it should have gdb_byte elements, not char elements.  Also, using
gdb::byte_vector is preferable, since it doesn't unnecessarily
zero-initialize the values.

Instead of adding a cast in the call to m_core_vec->core_read_registers,
I have changed core_read_registers' argument to be a gdb_byte* instead
of a char*.

gdb/ChangeLog:

	* gdbcore.h (struct core_fns) <core_read_registers>: Change
	core_reg_sect type to gdb_byte *.
	* arm-nbsd-nat.c (fetch_elfcore_registers): Likewise.
	* cris-tdep.c (fetch_core_registers): Likewise.
	* corelow.c (core_target::get_core_register_section): Change
	type of `contents` to gdb::byte_vector.
---
 gdb/arm-nbsd-nat.c | 2 +-
 gdb/corelow.c      | 2 +-
 gdb/cris-tdep.c    | 2 +-
 gdb/gdbcore.h      | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)
  

On 1/13/20 8:02 PM, Simon Marchi wrote:
> On 2020-01-13 2:40 p.m., Pedro Alves wrote:
>> On 1/12/20 8:17 PM, Simon Marchi wrote:
>>> -  contents = (char *) alloca (size);
>>> -  if (! bfd_get_section_contents (core_bfd, section, contents,
>>> +  std::vector<char> contents (size);
>>> +  if (! bfd_get_section_contents (core_bfd, section, contents.data (),
>>>  				  (file_ptr) 0, size))
>>>      {
>>
>> gdb::byte_vector
> 
> I used std::vector<char> because the original code also used char, and
> m_core_vec->core_read_registers also accepts a char * (although I
> could/should have used gdb::char_vector anyway).  However, gdb_byte
> probably makes more sense here.  I would push the patch below as a fixup
> if it looks good to you.

It does LGTM, thanks!

Pedro Alves
  

On 2020-01-13 5:04 p.m., Pedro Alves wrote:
> On 1/13/20 8:02 PM, Simon Marchi wrote:
>> On 2020-01-13 2:40 p.m., Pedro Alves wrote:
>>> On 1/12/20 8:17 PM, Simon Marchi wrote:
>>>> -  contents = (char *) alloca (size);
>>>> -  if (! bfd_get_section_contents (core_bfd, section, contents,
>>>> +  std::vector<char> contents (size);
>>>> +  if (! bfd_get_section_contents (core_bfd, section, contents.data (),
>>>>  				  (file_ptr) 0, size))
>>>>      {
>>>
>>> gdb::byte_vector
>>
>> I used std::vector<char> because the original code also used char, and
>> m_core_vec->core_read_registers also accepts a char * (although I
>> could/should have used gdb::char_vector anyway).  However, gdb_byte
>> probably makes more sense here.  I would push the patch below as a fixup
>> if it looks good to you.
> 
> It does LGTM, thanks!
> 
> Pedro Alves
> 


Thanks, it is now pushed.

Simon