This is the mail archive of the
binutils@sourceware.org
mailing list for the binutils project.
Re: [PATCH] MIPS/GAS: Fix DWARF-2 with branch swapping for MIPS16 code
"Maciej W. Rozycki" <macro@codesourcery.com> writes:
> BTW, I've been wondering about this construct:
>
> return mask & ~0;
>
> you've introduced in a couple of places.
Oops. Fixed below.
> Also why "can not" instead of "cannot"? My understanding of the
> subtleties of English is this essentially means we "are allowed not to
> swap" rather than we "are not allowed to swap". The usual disclaimer
> applies of course. ;)
Those comments were already there. I just moved them around.
> Finally I think the change below is needed as well. We shouldn't be
> relying on the meaning of FP_D for MIPS16 code as opcode flags are assumed
> to have a different meaning in the MIPS16 table. Granted, the location of
> the FP_D bit hasn't been assigned to anything (yet), so it's guaranteed to
> be zero and the check is harmless,
Yes. I checked that before writing it this way. It's guaranteed to be
harmless anyway, because "until" MIPS16 gets hardware FP support, we'd
never have any set bits.
I structured the code to be consistent with the GPR case. If you feel
strongly about it though, feel free to move the conditions inside the
existing "!mips_opts.mips16" check.
Richard
gas/
* config/tc-mips.c (gpr_read_mask, gpr_write_mask): Fix handling
of register 0.
Index: gas/config/tc-mips.c
===================================================================
--- gas/config/tc-mips.c 2011-07-04 21:00:54.000000000 +0100
+++ gas/config/tc-mips.c 2011-07-04 21:01:13.000000000 +0100
@@ -2450,7 +2450,8 @@ gpr_read_mask (const struct mips_cl_insn
if (pinfo2 & INSN2_READ_GPR_Z)
mask |= 1 << EXTRACT_OPERAND (RZ, *ip);
}
- return mask & ~0;
+ /* Don't include register 0. */
+ return mask & ~1;
}
/* Return the mask of core registers that IP writes. */
@@ -2492,7 +2493,8 @@ gpr_write_mask (const struct mips_cl_ins
if (pinfo2 & INSN2_WRITE_GPR_Z)
mask |= 1 << EXTRACT_OPERAND (RZ, *ip);
}
- return mask & ~0;
+ /* Don't include register 0. */
+ return mask & ~1;
}
/* Return the mask of floating-point registers that IP reads. */