From: "Sam Lauber" <sam124@operamail.com>
To: gcc@gcc.gnu.org
Subject: Unomitted frame pointers
Date: Fri, 10 Dec 2004 05:26:00 -0000 [thread overview]
Message-ID: <20041210052626.95AF72B2B86@ws5-7.us4.outblaze.com> (raw)
[-- Attachment #1: Type: text/plain, Size: 2006 bytes --]
Going back to useless assembly, a low-level Hello World with -fno-omit-frame-pointer:
.file "hello.c"
.section .rodata
.LC0:
.string "Hello World!\n"
.string ""
.text
.globl main
.type main, @function
main:
pushl %ebp
movl %esp, %ebp
subl $24, %esp
andl $-16, %esp
movl $0, %eax
addl $15, %eax
addl $15, %eax
shrl $4, %eax
sall $4, %eax
subl %eax, %esp
movl $16, 8(%esp)
movl $.LC0, 4(%esp)
movl $2, (%esp)
call write
movl $0, %eax
leave
ret
.size main, .-main
.section .note.GNU-stack,"",@progbits
.ident "GCC: (GNU) 3.4.3"
And the same C code with -fomit-frame-pointer:
.file "hello.c"
.section .rodata
.LC0:
.string "Hello World!\n"
.string ""
.text
.globl main
.type main, @function
main:
pushl %ebp
movl %esp, %ebp
subl $24, %esp
andl $-16, %esp
movl $0, %eax
addl $15, %eax
addl $15, %eax
shrl $4, %eax
sall $4, %eax
subl %eax, %esp
movl $16, 8(%esp)
movl $.LC0, 4(%esp)
movl $2, (%esp)
call write
movl $0, %eax
leave
ret
.size main, .-main
.section .note.GNU-stack,"",@progbits
.ident "GCC: (GNU) 3.4.3"
Clearly some one (or some code) isn't doing its job! The original C code is attached. I thought -fomit-frame-pointer is supposed to OMIT the frame pointer!
Samuel Lauber
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[-- Attachment #2: hello.c --]
[-- Type: application/octet-stream, Size: 65 bytes --]
int main(void)
{
write(2, "Hello World!\n\0", 16);
return 0;
}
next reply other threads:[~2004-12-10 5:26 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-12-10 5:26 Sam Lauber [this message]
2004-12-10 7:22 ` Eric Botcazou
2004-12-10 9:08 ` Richard Guenther
2004-12-10 15:44 Thomas R. Truscott
2004-12-10 16:05 ` jlh
2004-12-10 16:25 ` Dave Korn
2004-12-10 16:30 ` Nathan Sidwell
2004-12-10 16:41 ` Dave Korn
2004-12-10 17:54 ` Nathan Sidwell
2004-12-10 16:33 ` Andreas Schwab
2004-12-10 16:40 ` Dave Korn
2004-12-10 16:55 ` Thomas R. Truscott
2004-12-10 17:26 ` Paul Brook
2004-12-11 11:53 ` Kai Henningsen
2004-12-11 2:37 Sam Lauber
2004-12-11 2:44 Sam Lauber
2004-12-11 15:40 ` Nathan Sidwell
2004-12-11 15:45 ` Andreas Schwab
2004-12-11 16:15 Sam Lauber
2004-12-11 17:00 ` Eric Botcazou
2004-12-11 18:10 ` Robert Dewar
2004-12-13 6:16 ` Ranjit Mathew
2004-12-13 14:22 ` Robert Dewar
2004-12-13 23:36 ` Ben Elliston
2004-12-11 16:26 Sam Lauber
2004-12-11 16:42 ` Nathan Sidwell
2004-12-12 0:09 ` Peter Barada
2004-12-11 16:29 Sam Lauber
2004-12-12 1:33 ` Ian Lance Taylor
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