Re: REVISED PROPOSAL 000519.1 re Factored Offsets [joint with Keith]

[brender at gemgrp dot zko dot dec dot com (Ron 603-884-2088)]

Dave,

I am really confused.

First you say that SGI compilers do *not* use factored offsets for
DW_CFA_def_cfa_offset and DW_CFA_def_cfa:

>>   - Some implementions treat all four instructions as using factored
>>     offsets. Known examples are ARM's compiler for ARM, TI's compiler
>>     for ARM, SGI's compiler(s) for MIPS, Aonix's ObjectAda compiler.
>
>	SGI's compilers for MIPS do *not* fit in the above category.
>
>>   - Some implementation treat only DW_CFA_offset and DW_CFA_offset_extended
>>     as using factored offsets, which unfactored offsets are used for
>>     DW_CFA_def_cfa and DW_CFA_def_cfa_offset. Know examples are gcc
>>     and Compaq's compilers for Alpha.
>>
	SGI's compilers for MIPS fit in this second category with gcc.

Then you say they do (indeed, could not work without doing so):

>SGI/gcc are *using* the fact that the DW_CFA_def_cfa_offset and
>DW_CFA_def_cfa is positive and the factor is negative.  Without
>this the existing offsets and cfa setups on MIPS don't work
>because sgi uses a positive DW_CFA_def_cfa_offset (from the sp
>register value) and a negative (before factoring out a -4)
>DW_CFA_offset (from the CFA value).

    In particular, if SGI's implementation of DW_CFA_def_cfa_offset and
    DW_CFA_def_cfa do not use the factor, then the value of that factor
    is irrelevant cannot affect whether they work correctly or not...

Which ever category SGI fits in does not affect the main issue, of course
-- the fact remains that implementations do differ and we need to eliminate
that difference.

But, I would certainly like to have my facts right too...

???
Ron