[PATCH] Fix two potential memory leak

[luoxhu]

Hi,

On 2019/11/26 16:04, Jan Hubicka wrote:
>> Summary variables should be deleted at the end of write_summary.
>> It's first newed in generate_summary, and second newed in read_summary.
>> Therefore, delete the first in write_summary, delete the second in
>> execute.
>>
>> gcc/ChangeLog:
>>
>> 	2019-11-26  Luo Xiong Hu  <luoxhu@linux.ibm.com>
>>
>> 	* ipa-pure-const.c (pure_const_write_summary): Fix memory leak.
>> 	* ipa-sra.c (ipa_sra_write_summary): Likewise.
> 
> This is not going to work with -ffat-lto-objects because in this case
> IPA pass is executed later.  So you will need
> if (!flag_fat_lto_objects).
> 
> I think most IPA passes just waits for compiler to exit with LTO rather
> than free the summary.  ipa-fnsummary and ipa-prop allocate optimization
> summaries, too. Are those freed?

ipa-prop is a bit different, the ipcp_transformation_sum is only created in
read_summary, so need only delete once after execute.

ipa-fnsummary also forgot to free the ipa summaries at the end of 
write_summary.  The pass pass_ipa_free_fn_summary will delete all summaries 
in execute.

For -ffat-lto-objects, I suppose there would be no write_summary and 
read_summary?  so summaries are also newed once and delete once?  Thanks.

Anyway, lto1 will run after cc1, which means cc1 is finished, the memory is 
freed theoretically.

Xiong Hu


> 
> Honza
>> ---
>>   gcc/ipa-pure-const.c | 3 +++
>>   gcc/ipa-sra.c        | 5 +++++
>>   2 files changed, 8 insertions(+)
>>
>> diff --git a/gcc/ipa-pure-const.c b/gcc/ipa-pure-const.c
>> index a142e0cc8f6..89f334cedac 100644
>> --- a/gcc/ipa-pure-const.c
>> +++ b/gcc/ipa-pure-const.c
>> @@ -1260,6 +1260,9 @@ pure_const_write_summary (void)
>>       }
>>   
>>     lto_destroy_simple_output_block (ob);
>> +
>> +  delete funct_state_summaries;
>> +  funct_state_summaries = NULL;
>>   }
>>   
>>   
>> diff --git a/gcc/ipa-sra.c b/gcc/ipa-sra.c
>> index c6ed0f44b87..bbc5e84edfb 100644
>> --- a/gcc/ipa-sra.c
>> +++ b/gcc/ipa-sra.c
>> @@ -2671,6 +2671,11 @@ ipa_sra_write_summary (void)
>>     streamer_write_char_stream (ob->main_stream, 0);
>>     produce_asm (ob, NULL);
>>     destroy_output_block (ob);
>> +
>> +  ggc_delete (func_sums);
>> +  func_sums = NULL;
>> +  delete call_sums;
>> +  call_sums = NULL;
>>   }
>>   
>>   /* Read intraprocedural analysis information about E and all of its outgoing
>> -- 
>> 2.21.0.777.g83232e3864
>>