c++/5705: code generated for ARM interrupt("IRQ") attribute

[hans.buchmann@fhso.ch]

>Number:         5705
>Category:       c++
>Synopsis:       code generated for ARM interrupt("IRQ") attribute
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Feb 15 15:36:00 PST 2002
>Closed-Date:
>Last-Modified:
>Originator:     Hans Buchmann, Institute of Applied Sciences Northwestern Switzerland
>Release:        gcc version 3.0.2
>Organization:
>Environment:
Linux i686 kernel 2.4.3
>Description:
void irq() __attribute__ ((interrupt("IRQ")));

volatile unsigned* reg=(unsigned*)0x1234;

void irq()
{
 unsigned v=*reg;
 *reg=v;
}

compiling this code with the -S option gives the following assembler listing:
@ Generated by gcc 3.0.2 for ARM/elf
	.file	"error.cc"
	.global	reg
	.data
	.align	2
	.type	reg,object
	.size	reg,4
reg:
	.word	4660
	.text
	.align	2
	.global	_Z3irqv
	.type	_Z3irqv,function
_Z3irqv:
	@ Interrupt Service Routine.
	@ args = 0, pretend = 0, frame = 0
	@ frame_needed = 0, current_function_anonymous_args = 0
	@ link register save eliminated.
	stmfd	sp!, {r1, r2, r3}
	ldr	r2, .L3
	ldr	r0, [r2, #0]
	ldr	r1, [r0, #0]
	str	r1, [r0, #0]
	ldmfd	sp!, {r0, r1, r2, r3}
	subs	pc, lr, #4
.L4:
	.align	2
.L3:
	.word	reg
.Lfe1:
	.size	_Z3irqv,.Lfe1-_Z3irqv

comparing the lines 
 stmfd	sp!, {r1, r2, r3} 
and 
 ldmfd	sp!, {r0, r1, r2, r3}
it seems that stack will be corrupted 
>How-To-Repeat:
arm-elf-g++ -O3 -fomit-frame-pointer -S error.cc
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: