[ksh93-integration-discuss] ksh93 and default "-xarch"/"-xtarget" compiler flags in OS/Net...

[Roland Mainz]

Hi!

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While looking at "isaexec" machinery which selects the ksh93 binary to
be used I realised that it uses /usr/bin/i86/ksh93 on a Solaris version
which supports as minimum version the Intel Pentium-1 (or higher) ...

... my proposal would be to bump the default optimisation settings up to
match the minimum supported hardware for better performace - the
question is: Which flags should we use ?

- For SPARC we have the choice between the currenty used "sparcv8" or
"sparcv8plus" - "sparcv8plus" has the advantage of native 64bit
registers but there is a warning in
http://cvs.opensolaris.org/source/xref/on/usr/src/lib/libc/sparc/threads/sparc.il#58
which makes me worry about binary compatiblity:
-- snip --
We can't compile the 32-bit libc with -xarch=v8plus because
then %g5 would become a scratch register and we would break
32-bit applications that use %g5 as an invariant register.
-- snip --
... which simply raises the question whether we can mix "sparcv8" and
"sparcv8plus" code in one application. I guess the answer is "no"... but
I am not sure and I can't remember anymore since I am now more than 96h
awake... ;-(

Does anyone know whether a "sparcv8" application can link to a library
which was compiled with "sparcv8plus" ?

- For x86 I think we can use "-xarch=pentium_pro" (or
-xtarget=pentium_pro ?) and move the binary to
/usr/bin/pentium_pro/ksh93 ... are there any objections against that ?

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Bye,
Roland

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