* Disassemble the .lib file compiled with gcc-arm-8.3-2019.03-x86_64-arm-eabi compilation tool chain, and found that malloc is optimized to calloc.
@ 2020-10-30 8:53 YaRu Wei(魏亚茹)
2020-11-04 15:45 ` Richard Earnshaw
0 siblings, 1 reply; 3+ messages in thread
From: YaRu Wei(魏亚茹) @ 2020-10-30 8:53 UTC (permalink / raw)
To: gcc
Dear gcc:
I find that disassemble the .lib file compiled with gcc-arm-8.3-2019.03-x86_64-arm-eabi compilation tool chain, and found that malloc is optimized to calloc. I want to know under what circumstances malloc will be optimized to calloc?
Thanks
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Disassemble the .lib file compiled with gcc-arm-8.3-2019.03-x86_64-arm-eabi compilation tool chain, and found that malloc is optimized to calloc.
2020-10-30 8:53 Disassemble the .lib file compiled with gcc-arm-8.3-2019.03-x86_64-arm-eabi compilation tool chain, and found that malloc is optimized to calloc YaRu Wei(魏亚茹)
@ 2020-11-04 15:45 ` Richard Earnshaw
2020-11-05 1:06 ` 答复: " YaRu Wei(魏亚茹)
0 siblings, 1 reply; 3+ messages in thread
From: Richard Earnshaw @ 2020-11-04 15:45 UTC (permalink / raw)
To: YaRu Wei(魏亚茹), gcc
On 30/10/2020 08:53, YaRu Wei(魏亚茹) wrote:
> Dear gcc:
> I find that disassemble the .lib file compiled with gcc-arm-8.3-2019.03-x86_64-arm-eabi compilation tool chain, and found that malloc is optimized to calloc. I want to know under what circumstances malloc will be optimized to calloc?
> Thanks
>
I would presume this would happen if the call to malloc were immediately
followed by a call to memset to clear the memory (or an equivalent
software coded implementation of memset were detected). Generally,
calloc has a better idea of the memory being allocated and can optimize
the clearing step if it knows the memory is already zeroed.
R.
^ permalink raw reply [flat|nested] 3+ messages in thread
* 答复: Disassemble the .lib file compiled with gcc-arm-8.3-2019.03-x86_64-arm-eabi compilation tool chain, and found that malloc is optimized to calloc.
2020-11-04 15:45 ` Richard Earnshaw
@ 2020-11-05 1:06 ` YaRu Wei(魏亚茹)
0 siblings, 0 replies; 3+ messages in thread
From: YaRu Wei(魏亚茹) @ 2020-11-05 1:06 UTC (permalink / raw)
To: Richard Earnshaw, gcc
Thanks.
________________________________
发件人: Richard Earnshaw <Richard.Earnshaw@foss.arm.com>
发送时间: 2020年11月4日 23:45:39
收件人: YaRu Wei(魏亚茹); gcc@gcc.gnu.org
主题: Re: Disassemble the .lib file compiled with gcc-arm-8.3-2019.03-x86_64-arm-eabi compilation tool chain, and found that malloc is optimized to calloc.
On 30/10/2020 08:53, YaRu Wei(魏亚茹) wrote:
> Dear gcc:
> I find that disassemble the .lib file compiled with gcc-arm-8.3-2019.03-x86_64-arm-eabi compilation tool chain, and found that malloc is optimized to calloc. I want to know under what circumstances malloc will be optimized to calloc?
> Thanks
>
I would presume this would happen if the call to malloc were immediately
followed by a call to memset to clear the memory (or an equivalent
software coded implementation of memset were detected). Generally,
calloc has a better idea of the memory being allocated and can optimize
the clearing step if it knows the memory is already zeroed.
R.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2020-10-30 8:53 Disassemble the .lib file compiled with gcc-arm-8.3-2019.03-x86_64-arm-eabi compilation tool chain, and found that malloc is optimized to calloc YaRu Wei(魏亚茹)
2020-11-04 15:45 ` Richard Earnshaw
2020-11-05 1:06 ` 答复: " YaRu Wei(魏亚茹)
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