* [PATCH 10/20] MIPS/GAS: Fail on 64-bit addresses used with LI
@ 2010-12-02 19:20 Maciej W. Rozycki
2010-12-07 10:25 ` Richard Sandiford
0 siblings, 1 reply; 4+ messages in thread
From: Maciej W. Rozycki @ 2010-12-02 19:20 UTC (permalink / raw)
To: Richard Sandiford; +Cc: Catherine Moore, binutils
Hi,
This change adds a suitable assertion to the LI macro where 64-bit
addresses are not expected and not handled correctly.
2010-12-02 Maciej W. Rozycki <macro@codesourcery.com>
gas/
* config/tc-mips.c (macro)[M_LI_DD]: Fail if a 64-bit address is
truncated to 32 bits.
OK to apply?
Maciej
binutils-gas-mips-lidd-assert.diff
Index: binutils-fsf-trunk-quilt/gas/config/tc-mips.c
===================================================================
--- binutils-fsf-trunk-quilt.orig/gas/config/tc-mips.c 2010-12-01 21:05:50.000000000 +0000
+++ binutils-fsf-trunk-quilt/gas/config/tc-mips.c 2010-12-01 21:05:51.000000000 +0000
@@ -7039,6 +7039,7 @@ macro (struct mips_cl_insn *ip)
else
{
/* FIXME: This won't work for a 64 bit address. */
+ gas_assert (HAVE_32BIT_ADDRESSES);
macro_build_lui (&offset_expr, AT);
}
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH 10/20] MIPS/GAS: Fail on 64-bit addresses used with LI
2010-12-02 19:20 [PATCH 10/20] MIPS/GAS: Fail on 64-bit addresses used with LI Maciej W. Rozycki
@ 2010-12-07 10:25 ` Richard Sandiford
2010-12-09 16:09 ` Maciej W. Rozycki
0 siblings, 1 reply; 4+ messages in thread
From: Richard Sandiford @ 2010-12-07 10:25 UTC (permalink / raw)
To: Maciej W. Rozycki; +Cc: Catherine Moore, binutils
Patch 9 is OK.
"Maciej W. Rozycki" <macro@codesourcery.com> writes:
> binutils-gas-mips-lidd-assert.diff
> Index: binutils-fsf-trunk-quilt/gas/config/tc-mips.c
> ===================================================================
> --- binutils-fsf-trunk-quilt.orig/gas/config/tc-mips.c 2010-12-01 21:05:50.000000000 +0000
> +++ binutils-fsf-trunk-quilt/gas/config/tc-mips.c 2010-12-01 21:05:51.000000000 +0000
> @@ -7039,6 +7039,7 @@ macro (struct mips_cl_insn *ip)
> else
> {
> /* FIXME: This won't work for a 64 bit address. */
> + gas_assert (HAVE_32BIT_ADDRESSES);
> macro_build_lui (&offset_expr, AT);
> }
>
Not OK. This trivially triggers for:
li.d $f2,1.1
assembled with -mabi=64 -G0.
Richard
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH 10/20] MIPS/GAS: Fail on 64-bit addresses used with LI
2010-12-07 10:25 ` Richard Sandiford
@ 2010-12-09 16:09 ` Maciej W. Rozycki
2010-12-09 17:41 ` Richard Sandiford
0 siblings, 1 reply; 4+ messages in thread
From: Maciej W. Rozycki @ 2010-12-09 16:09 UTC (permalink / raw)
To: Richard Sandiford; +Cc: Catherine Moore, binutils
On Tue, 7 Dec 2010, Richard Sandiford wrote:
> > binutils-gas-mips-lidd-assert.diff
> > Index: binutils-fsf-trunk-quilt/gas/config/tc-mips.c
> > ===================================================================
> > --- binutils-fsf-trunk-quilt.orig/gas/config/tc-mips.c 2010-12-01 21:05:50.000000000 +0000
> > +++ binutils-fsf-trunk-quilt/gas/config/tc-mips.c 2010-12-01 21:05:51.000000000 +0000
> > @@ -7039,6 +7039,7 @@ macro (struct mips_cl_insn *ip)
> > else
> > {
> > /* FIXME: This won't work for a 64 bit address. */
> > + gas_assert (HAVE_32BIT_ADDRESSES);
> > macro_build_lui (&offset_expr, AT);
> > }
> >
>
> Not OK. This trivially triggers for:
>
> li.d $f2,1.1
>
> assembled with -mabi=64 -G0.
And rightfully so, broken code is produced:
$ cat li_d.s
li.d $f2, 1.1
$ mips-sde-elf-as -mabi=64 -G0 -o li_d.o li_d.s
$ mips-sde-elf-ld -m elf64btsmip -e0 -o li_d li_d.o
$ mips-sde-elf-objdump -dt li_d
li_d: file format elf64-tradbigmips
SYMBOL TABLE:
0000000120000078 l d .MIPS.options 0000000000000000 .MIPS.options
0000000120000078 l d .text 0000000000000000 .text
0000000120000080 l d .rodata 0000000000000000 .rodata
0000000120010088 g .rodata 0000000000000000 _fdata
0000000120018080 g *ABS* 0000000000000000 _gp
0000000120000078 g .text 0000000000000000 _ftext
0000000120010088 g *ABS* 0000000000000000 __bss_start
0000000120010088 g *ABS* 0000000000000000 _edata
0000000120010088 g *ABS* 0000000000000000 _end
0000000120010088 g *ABS* 0000000000000000 _fbss
Disassembly of section .text:
0000000120000078 <_ftext>:
120000078: 3c012000 lui at,0x2000
12000007c: d4220080 ldc1 $f2,128(at)
$
I don't think the code above gets at .rodata, do you?
With some tweaking we should be able to reuse code from M_L_DAB to handle
this case (i.e. jump to there with some prearrangements), but I may not
have the time to implement this stuff properly now. Why do you think
silently making broken code is better than signalling an internal error
(which it is) here?
Maciej
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH 10/20] MIPS/GAS: Fail on 64-bit addresses used with LI
2010-12-09 16:09 ` Maciej W. Rozycki
@ 2010-12-09 17:41 ` Richard Sandiford
0 siblings, 0 replies; 4+ messages in thread
From: Richard Sandiford @ 2010-12-09 17:41 UTC (permalink / raw)
To: Maciej W. Rozycki; +Cc: Catherine Moore, binutils
"Maciej W. Rozycki" <macro@codesourcery.com> writes:
> On Tue, 7 Dec 2010, Richard Sandiford wrote:
>> Not OK. This trivially triggers for:
>>
>> li.d $f2,1.1
>>
>> assembled with -mabi=64 -G0.
>
> And rightfully so, broken code is produced:
>
> $ cat li_d.s
> li.d $f2, 1.1
> $ mips-sde-elf-as -mabi=64 -G0 -o li_d.o li_d.s
> $ mips-sde-elf-ld -m elf64btsmip -e0 -o li_d li_d.o
> $ mips-sde-elf-objdump -dt li_d
>
> li_d: file format elf64-tradbigmips
>
> SYMBOL TABLE:
> 0000000120000078 l d .MIPS.options 0000000000000000 .MIPS.options
> 0000000120000078 l d .text 0000000000000000 .text
> 0000000120000080 l d .rodata 0000000000000000 .rodata
> 0000000120010088 g .rodata 0000000000000000 _fdata
> 0000000120018080 g *ABS* 0000000000000000 _gp
> 0000000120000078 g .text 0000000000000000 _ftext
> 0000000120010088 g *ABS* 0000000000000000 __bss_start
> 0000000120010088 g *ABS* 0000000000000000 _edata
> 0000000120010088 g *ABS* 0000000000000000 _end
> 0000000120010088 g *ABS* 0000000000000000 _fbss
>
>
>
> Disassembly of section .text:
>
> 0000000120000078 <_ftext>:
> 120000078: 3c012000 lui at,0x2000
> 12000007c: d4220080 ldc1 $f2,128(at)
> $
>
> I don't think the code above gets at .rodata, do you?
You're just repeating what the FIXME already says: that the code doesn't
work correctly with addresses whose values exceed the 32-bit range.
I wasn't disputing that.
> With some tweaking we should be able to reuse code from M_L_DAB to handle
> this case (i.e. jump to there with some prearrangements), but I may not
> have the time to implement this stuff properly now. Why do you think
> silently making broken code is better than signalling an internal error
> (which it is) here?
An assertion failure is also a bug. Assertion failures are for
conditions that we think should never occur, so we shouldn't add
an assertion failure for a condition that is known to trigger.
We should either fix the FIXME or issue a proper diagnostic.
Richard
^ permalink raw reply [flat|nested] 4+ messages in thread
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2010-12-02 19:20 [PATCH 10/20] MIPS/GAS: Fail on 64-bit addresses used with LI Maciej W. Rozycki
2010-12-07 10:25 ` Richard Sandiford
2010-12-09 16:09 ` Maciej W. Rozycki
2010-12-09 17:41 ` Richard Sandiford
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