C++ support in DSLINUX

[Amadeus]

Hmmmm....

On Monday 16 October 2006 22:58, Amadeus wrote:

in rtest.o, I see:

000003d4 <puts>:
     3d4:       e92d4030        stmdb   sp!, {r4, r5, lr}
     3d8:       e59f3038        ldr     r3, [pc, #56]   ; 418 
<puts+0x44>
     3dc:       e79a2003        ldr     r2, [sl, r3]
     3e0:       e5924000        ldr     r4, [r2]
     3e4:       e1a01004        mov     r1, r4
     3e8:       eb000089        bl      614 <__fputs_unlocked>
     3ec:       e1a05000        mov     r5, r0
     3f0:       e3750001        cmn     r5, #1  ; 0x1
     3f4:       e1a01004        mov     r1, r4
     3f8:       e3a0000a        mov     r0, #10 ; 0xa
     3fc:       0a000003        beq     410 <puts+0x3c>
     400:       eb00003c        bl      4f8 <__fputc_unlocked>
     404:       e2855001        add     r5, r5, #1      ; 0x1
     408:       e3700001        cmn     r0, #1  ; 0x1
     40c:       01a05000        moveq   r5, r0
     410:       e1a00005        mov     r0, r5
     414:       e8bd8030        ldmia   sp!, {r4, r5, pc}
     418:       0000003c        andeq   r0, r0, ip, lsr r0

obviously, the value 3c at 418 is an offset into a table. Base address 
of this table is in register sl. Value is read from the table and 
dereferenced.

My problem is that the value in r1/r4 is pointing to page 0.

So I have a relocation error!

The value read in r1/r4 is supposed to be a stream * named "stdout".
This stream pointer is defined in /uClibc/libc/stdio/_stdio.c:

static FILE _stdio_streams[] = {
	__STDIO_INIT_FILE_STRUCT(_stdio_streams[0], \
							 __FLAG_LBF|__FLAG_READONLY, \
							 0, \
							 _stdio_streams + 1, \
							 _fixed_buffers, \
							 BUFSIZ ),
	__STDIO_INIT_FILE_STRUCT(_stdio_streams[1], \
							 __FLAG_LBF|__FLAG_WRITEONLY, \
							 1, \
							 _stdio_streams + 2, \
							 _fixed_buffers + BUFSIZ, \
							 BUFSIZ ),
	__STDIO_INIT_FILE_STRUCT(_stdio_streams[2], \
							 __FLAG_NBF|__FLAG_WRITEONLY, \
							 2, \
							 NULL, \
							 NULL, \
							 0 )
};

FILE *stdin  = _stdio_streams;
FILE *stdout = _stdio_streams + 1;
FILE *stderr = _stdio_streams + 2;


The problem is here that without valid stdout/stderr streams, debugging 
is very difficult....

This error is ONLY there if there are c++ items (classes, objects, etc) 
in the file.

A simple rtest.xxx with a printf() and no classes is fine.

Any idea of how to debug? There must be something wrong with the binfmt 
relocations...

regards
Amadeus


-- 
We're back to the times when men were men 
and wrote their own device drivers.

(Linus Torvalds)