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* [Bug c/28194] New: R_ARM_GOTOFF32 breaks execute-in-place
@ 2006-06-28 17:30 sjackman at gmail dot com
2009-04-29 17:12 ` [Bug target/28194] " rearnsha at gcc dot gnu dot org
2009-05-09 6:05 ` jsun at junsun dot net
0 siblings, 2 replies; 3+ messages in thread
From: sjackman at gmail dot com @ 2006-06-28 17:30 UTC (permalink / raw)
To: gcc-bugs
Execute-in-place (XIP) code, commonly used with uClinux, places the .text
section in flash and the .data section in RAM. GCC 4.1 emits R_ARM_GOTOFF32
relocations for symbols in the .text segment relative to the GOT, which is in
the .data segment. This new behaviours breaks XIP. See the following diff,
which illustrates this new behaviour.
Cheers,
Shaun
$ cat f.c
void g(void (*h)(void)) {}
static void f(void) { g(f); }
$ diff -u f.s-4.0.3 f.s-4.1.1
--- f.s-4.0.3 2006-06-28 09:32:54.044964568 -0600
+++ f.s-4.1.1 2006-06-28 08:55:49.880089024 -0600
@@ -8,11 +8,12 @@
.type g, %function
g:
push {r7, lr}
- mov r7, sp
sub sp, sp, #4
- sub r3, r7, #4
+ add r7, sp, #0
+ mov r3, r7
str r0, [r3]
mov sp, r7
+ add sp, sp, #4
@ sp needed for prologue
pop {r7, pc}
.size g, .-g
@@ -22,10 +23,9 @@
.type f, %function
f:
push {r7, lr}
- mov r7, sp
+ add r7, sp, #0
ldr r3, .L5
add r3, r3, sl
- ldr r3, [r3]
mov r0, r3
bl g
mov sp, r7
@@ -34,6 +34,6 @@
.L6:
.align 2
.L5:
- .word f(GOT)
+ .word f(GOTOFF)
.size f, .-f
- .ident "GCC: (GNU) 4.0.3"
+ .ident "GCC: (GNU) 4.1.1"
--
Summary: R_ARM_GOTOFF32 breaks execute-in-place
Product: gcc
Version: 4.1.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: sjackman at gmail dot com
GCC build triplet: i686-pc-linux-gnu
GCC host triplet: i686-pc-linux-gnu
GCC target triplet: arm-unknown-elf
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28194
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug target/28194] R_ARM_GOTOFF32 breaks execute-in-place
2006-06-28 17:30 [Bug c/28194] New: R_ARM_GOTOFF32 breaks execute-in-place sjackman at gmail dot com
@ 2009-04-29 17:12 ` rearnsha at gcc dot gnu dot org
2009-05-09 6:05 ` jsun at junsun dot net
1 sibling, 0 replies; 3+ messages in thread
From: rearnsha at gcc dot gnu dot org @ 2009-04-29 17:12 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from rearnsha at gcc dot gnu dot org 2009-04-29 17:12 -------
The ARM port does not currently support XIP (if it worked previously, it was by
chance, not design). The generated code is exactly what is wanted in a normal
shared library environment, so I'm not about to start changing the default
behaviour.
If you want to have XIP, then implement an option that does this and submit the
patches for review.
--
rearnsha at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |WONTFIX
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28194
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug target/28194] R_ARM_GOTOFF32 breaks execute-in-place
2006-06-28 17:30 [Bug c/28194] New: R_ARM_GOTOFF32 breaks execute-in-place sjackman at gmail dot com
2009-04-29 17:12 ` [Bug target/28194] " rearnsha at gcc dot gnu dot org
@ 2009-05-09 6:05 ` jsun at junsun dot net
1 sibling, 0 replies; 3+ messages in thread
From: jsun at junsun dot net @ 2009-05-09 6:05 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from jsun at junsun dot net 2009-05-09 06:04 -------
We have confirmed that this problem still exists in gcc 4.3.3.
It appears other than this problem, XIP on ARM actually works. XIP on ARM also
worked fine with gcc 3.x, with "-fpic -msingle-pic-base" compile option.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28194
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2009-05-09 6:05 UTC | newest]
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2006-06-28 17:30 [Bug c/28194] New: R_ARM_GOTOFF32 breaks execute-in-place sjackman at gmail dot com
2009-04-29 17:12 ` [Bug target/28194] " rearnsha at gcc dot gnu dot org
2009-05-09 6:05 ` jsun at junsun dot net
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