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Re: [PATCH] Omit frame pointer and fix %ebp by default on x86 (take3)
- From: Roger Sayle <roger at eyesopen dot com>
- To: Jakub Jelinek <jakub at redhat dot com>
- Cc: Andrew Haley <aph at redhat dot com>, <gcc-patches at gcc dot gnu dot org>, Richard Henderson <rth at redhat dot com>
- Date: Mon, 16 Aug 2004 13:26:17 -0600 (MDT)
- Subject: Re: [PATCH] Omit frame pointer and fix %ebp by default on x86 (take3)
On Mon, 16 Aug 2004, Jakub Jelinek wrote:
> How is that better from making -fomit-frame-pointer
> -fasynchronous-unwind-tables the default.
Because -fasynchronous-unwind-tables results in a dramatic increase
in object file size. It also only works on targets with suitable
debugging file formats.
GCC competes with the Microsoft and Intel compilers on Microsoft
Windows, and the arguments for asynchronous-unwind-tables and the
need to preserve glibc's backtrace functionality don't really hold
much water there.
It's my understanding that none of the GCC compilers themselves
require the functionality of backtrace, the GDB executable doesn't
require it, the Linux kernel doesn't require it, none of the
applications in the SPEC benchmark suite require it, none of
OpenEye's applications require it. It's easy to list the people
who suffer from preserving the frame-pointer, is it only Java
folks that are causing this performance hold-up?
Roger
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