From: Danny Backx <danny.backx@scarlet.be>
To: Nick Clifton <nickc@redhat.com>
Cc: binutils <binutils@sourceware.org>
Subject: Re: puzzled - old release works, newer doesn't
Date: Thu, 27 Apr 2006 01:32:00 -0000 [thread overview]
Message-ID: <1146082022.4109.25.camel@dannypc> (raw)
In-Reply-To: <444E5ABD.8070209@redhat.com>
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Nick & others,
Thanks for the input, but the --support-old-code flag doesn't appear to
be the answer. And yes I am trying to replace GCC, GAS, and LD at the
same time, I'm currently playing with binutils from CVS. No improvement
from that either.
I did some more digging since my last message, below I'll indicate what
I see. The hello.s I use is still the same. As you said, the output
pasted in below is from the fully linked exe file, not the .obj file.
The executables I create from hello.s lack at least in two areas :
- branches are off
- references to literal strings are off
In the piece below, you'll see that the statement at 11044 branches to
an address 8 bytes too far to reach _fopen, also at 1106c and further
you'll see three pointers all pointing to the same address. This is
wrong too.
The piece produced by the new compiler+binutils :
0001101c <_WinMain>:
1101c: e1a0c00d mov ip, sp
11020: e92dd800 stmdb sp!, {fp, ip, lr, pc}
11024: e24cb004 sub fp, ip, #4 ; 0x4
11028: e24dd014 sub sp, sp, #20 ; 0x14
1102c: e50b0010 str r0, [fp, #-16]
11030: e50b1014 str r1, [fp, #-20]
11034: e50b2018 str r2, [fp, #-24]
11038: e50b301c str r3, [fp, #-28]
1103c: e59f0028 ldr r0, [pc, #40] ; 1106c
<_WinMain+0x50>
11040: e59f1028 ldr r1, [pc, #40] ; 11070
<_WinMain+0x54>
11044: eb0005da bl 127b4 <_fopen+0x8>
11048: e1a03000 mov r3, r0
1104c: e50b3020 str r3, [fp, #-32]
11050: e51b0020 ldr r0, [fp, #-32]
11054: e59f1018 ldr r1, [pc, #24] ; 11074
<_WinMain+0x58>
11058: eb0005de bl 127d8 <_fprintf+0x8>
1105c: e51b0020 ldr r0, [fp, #-32]
11060: eb0005e4 bl 127f8 <_fclose+0x8>
11064: e3a00000 mov r0, #0 ; 0x0
11068: eb00061b bl 128dc <_exit+0x8>
1106c: 00023000 andeq r3, r2, r0
11070: 00023000 andeq r3, r2, r0
11074: 00023000 andeq r3, r2, r0
For reference, here is a similar piece produced with old compiler
+binutils :
0001101c <_WinMain>:
1101c: e1a0c00d mov ip, sp
11020: e92dd800 stmdb sp!, {fp, ip, lr, pc}
11024: e24cb004 sub fp, ip, #4 ; 0x4
11028: e24dd014 sub sp, sp, #20 ; 0x14
1102c: e50b0010 str r0, [fp, #-16]
11030: e50b1014 str r1, [fp, #-20]
11034: e50b2018 str r2, [fp, #-24]
11038: e50b301c str r3, [fp, #-28]
1103c: e59f0028 ldr r0, [pc, #40] ; 1106c
<_WinMain+0x50>
11040: e59f1028 ldr r1, [pc, #40] ; 11070
<_WinMain+0x54>
11044: eb0005d8 bl 127ac <_fopen>
11048: e1a03000 mov r3, r0
1104c: e50b3020 str r3, [fp, #-32]
11050: e51b0020 ldr r0, [fp, #-32]
11054: e59f1018 ldr r1, [pc, #24] ; 11074
<_WinMain+0x58>
11058: eb0005dc bl 127d0 <_fprintf>
1105c: e51b0020 ldr r0, [fp, #-32]
11060: eb0005e2 bl 127f0 <_fclose>
11064: e3a00000 mov r0, #0 ; 0x0
11068: eb000619 bl 128d4 <_exit>
1106c: 00023000 andeq r3, r2, r0
11070: 0002301c andeq r3, r2, ip, lsl r0
11074: 00023020 andeq r3, r2, r0, lsr #32
In both cases, the pointers should refer to this :
Contents of section .rdata:
23000 2f73746f 72616765 20636172 642f6465 /storage card/de
23010 76656c2f 6c6f672e 74787400 77000000 vel/log.txt.w...
23020 48656c6c 6f0d0a00 57434554 52414345 Hello...WCETRACE
There might be other problems with the file produced, these are the ones
I discovered. Unfortunately they appear more than enough reason for the
executable not to do anything sensible :-(
Quite frankly I have just started looking into binutils so its source is
still a mystery so all clues are appreciated.
I haven't bothered testing the recent pre-release.
Danny
On Tue, 2006-04-25 at 18:22 +0100, Nick Clifton wrote:
> Hi Danny,
>
> > The old environment is based on gcc 3.4.2, gas 2.13.2, binutils 2.15.
> > (Yes there's a mixup there.) The new environment is using gcc 4.1 and
> > binutils 2.16. In all versions, the target platform is "arm-wince-pe".
> >
> > The person who created this distribution explains the mixup by saying
> > that the GAS from 2.13 works, whereas the one in newer binutils doesn't.
> >
> > My personal experience with the 2.16 release appears to confirm that.
>
> Are you upgrading to the new GCC new GAS and new LD all at the same time
> ? If not then that might be the cause.
>
> Are you aware of the --support-old-code linker switch which is specific
> to the arm-wince-pe target ? Using this might help you.
>
> Using the latest binutils sources from CVS repository might also help.
> If not then I would recommend comparing a disassembly of a working
> binary and broken binary to see where there are changes. (Do not
> compare the object files, but linked binaries. This should allow you to
> find out how relocs may have been processed differently).
>
> Cheers
> Nick
>
--
Danny Backx ; danny.backx - at - scarlet.be ; http://danny.backx.info
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prev parent reply other threads:[~2006-04-26 20:07 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-04-11 23:06 Danny Backx
2006-04-25 17:39 ` Nick Clifton
2006-04-25 21:15 ` Pedro Alves
2006-04-27 2:23 ` Pedro Alves
2006-04-27 1:32 ` Danny Backx [this message]
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