Re: [PATCH 1/2] Memory statistics enhancement.

[Martin Liška <mliska at suse dot cz>]

On 06/03/2015 03:18 PM, Jeff Law wrote:
> On 06/03/2015 03:14 AM, Martin Liška wrote:
>> On 06/02/2015 07:17 PM, Jeff Law wrote:
>>> On 06/02/2015 09:05 AM, Martin Liška wrote:
>>>> On 06/02/2015 03:58 PM, Jeff Law wrote:
>>>>> On 06/01/2015 10:16 AM, mliska wrote:
>>>>>> Hi.
>>>>>>
>>>>>> Following 2 patches improve memory statistics infrastructure. First one
>>>>>> ports pool allocator to the new infrastructure. And the second one makes
>>>>>> column alignment properly.
>>>>>>
>>>>>> Both can bootstrap on x86_64-linux-pc and survive regression tests.
>>>>>>
>>>>>> Ready for trunk?
>>>>>> Thank you,
>>>>>> Martin
>>>>>>
>>>>>> Port pool-allocator memory stats to a new infrastructure.
>>>>>>
>>>>>> gcc/ChangeLog:
>>>>>>
>>>>>> 2015-06-02  Martin Liska  <mliska@suse.cz>
>>>>>>
>>>>>>       * alloc-pool.c (allocate_pool_descriptor): Remove.
>>>>>>       (struct pool_output_info): Likewise.
>>>>>>       (print_alloc_pool_statistics): Likewise.
>>>>>>       (dump_alloc_pool_statistics): Likewise.
>>>>>>       * alloc-pool.h (struct pool_usage): New struct.
>>>>>>       (pool_allocator::initialize): Change usage of memory statistics
>>>>>>       to a new interface.
>>>>>>       (pool_allocator::release): Likewise.
>>>>>>       (pool_allocator::allocate): Likewise.
>>>>>>       (pool_allocator::remove): Likewise.
>>>>>>       * mem-stats-traits.h (enum mem_alloc_origin): Add new enum value
>>>>>>       for a pool allocator.
>>>>>>       * mem-stats.h (struct mem_location): Add new ctor.
>>>>>>       (struct mem_usage): Add counter for number of
>>>>>>       instances.
>>>>>>       (mem_alloc_description::register_descriptor): New overload of
>>>>>>       the function.
>>>>>    -
>>>>>
>>>>>> diff --git a/gcc/alloc-pool.h b/gcc/alloc-pool.h
>>>>>> index 96a1342..a1727ce 100644
>>>>>> --- a/gcc/alloc-pool.h
>>>>>> +++ b/gcc/alloc-pool.h
>>>>>
>>>>>> +  /* Dump usage coupled to LOC location, where TOTAL is sum of all rows.  */
>>>>>> +  inline void dump (mem_location *loc, mem_usage &total) const
>>>>>> +  {
>>>>>> +    char s[4096];
>>>>>> +    sprintf (s, "%s:%i (%s)", loc->get_trimmed_filename (),
>>>>>> +         loc->m_line, loc->m_function);
>>>>> Static sized buffer used in a sprintf where the strings are potentially user controlled.   Not good, even in dumping code, still not good.
>>>>>
>>>>>> +
>>>>>> +    s[48] = '\0';
>>>>> ?!?  Presumably you're just truncating the output line here for the subsequent fprintf call.  Consider using a const with a symbolic name rather than the magic "48".  I say "consider" because there's magic constants all over the place in the dumping code. So it may not be worth the effort.  Your call.
>>>>>
>>>>>    +
>>>>>> +  /* Dump header with NAME.  */
>>>>>> +  static inline void dump_header (const char *name)
>>>>>> +  {
>>>>>> +    fprintf (stderr, "%-32s%-48s %6s%11s%16s%17s%12s\n", "Pool name", name,
>>>>>> +         "Pools", "Leak", "Peak", "Times", "Elt size");
>>>>>> +    print_dash_line ();
>>>>>> +  }
>>>>>> +
>>>>>> +  /* Dump footer.  */
>>>>>> +  inline void dump_footer ()
>>>>>> +  {
>>>>>> +    print_dash_line ();
>>>>>> +    fprintf (stderr, "%s%75li%10li\n", "Total", (long)m_instances,
>>>>>> +         (long)m_allocated);
>>>>>> +    print_dash_line ();
>>>>>> +  }
>>>>> Note the header is static inline, footer is just inline.  Please try to make them consistent.
>>> It doesn't look like you did anything with this.  Is there a reason that the dump_header and dump_footer have different linkage?  Also the linkage/return type for dump_header should be on its own line.
>>>
>>> With that fixed, this is OK for the trunk.
>>>
>>> jeff
>>
>> Hi Jeff.
>>
>> Different linkage is because of dump_header is just a generic header unrelated to any real numbers.
>> On the other hand, dump_footer is called on a total instance.
> Right, but why does that affect linkage?   Sorry to keep harping on this minor issue, but something just doesn't make any sense to me.

Hi.

That's fine, I would like to explain that difference. Each of these two functions are called in a bit different way:
T::dump_header (mem_location::get_origin_name (origin)); // that's why the function is static
total.dump_footer (); // that's why the function is method

Martin

> 
>>
>> I've just identified that the whole memory statistics infrastructure lacks correct GNU formatting
>> in case of C++ member functions. I'm going to fix it in a different patch.
> Excellent.  Thanks,
> 
> jeff