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Re: [PATCH] microMIPS/GAS: Avoid relocation overflow with forced 16-bit branches

"Maciej W. Rozycki" <> writes:
> On Thu, 25 Oct 2012, Richard Sandiford wrote:
>> > Overall it looks to me the whole idea of using fixp->fx_size to check for 
>> > relocatable field overflows is missing the point, at least for the MIPS 
>> > target and relocations in text, where the size of the fixup reflects the 
>> > width of the instruction a relocation is applied to and has little to do 
>> > with the range supported.
>> >
>> >  Anyway, to fix this immediate problem I have gladly accepted Chao-ying's 
>> > proposal.
>> >
>> >  No regressions in testing across the usual MIPS targets.  OK to apply?
>> >
>> > 2012-10-24  Chao-ying Fu  <>
>> >
>> > 	gas/
>> > 	* config/tc-mips.c (append_insn): Set fx_no_overflow for 16-bit
>> > 	microMIPS branch relocations.
>> >
>> > 	gas/testsuite/
>> > 	* gas/mips/micromips-b16.d: New test.
>> > 	* gas/mips/micromips-b16.s: New test source.
>> > 	* gas/mips/mips.exp: Run the new test.
>> I take your point about the write.c check (been hit by that before too),
>> but I suppose the obvious question is: do we still report branches that
>> genuinely overflow?
>  Of course we do, for symbols resolved at the assembly time GAS does that 
> and for all the others the linker does:

OK, OK, it was a genuine question :-)  Thanks for the example though.

>> Would be nice to have a test for that too, if we don't already.
>  We do have some tests, but only for BPOSGE32. ;)  And for the linker we 
> check some other relocations, but we don't check the branch ones.  I'll 
> see what I can do, but I hope that is not a prerequisite for this bug fix, 
> I'd like to tick it off.

Nope, not a prerequisite.  Patch is OK, thanks.


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