does -xtarget or -xchip predefine any macros that define the chip?
Hi,
I am working on a project where I need to compile different versions of the code for the different UltraSPARC chips. I can easily tell the compiler to compile for an US-IV on my US-IIIi development machine, e.g. with the -xtarget=ultra4 flag.Does the compiler define some internal macros, that make it possible to find out which chip it compiles for? E.g. something like
[code]
#ifdef __US-IV
<statements>
#endif
#ifdef __US-IIICu
<statements>
#endif
[/code]
Regards,
Bernd
[562 byte] By [
dtugrid] at [2007-11-26 9:12:03]
# 1
You can see all macros that compiler defines when using [b]-v[/b] compiler option. Among other information, it shows compiler front-end invocation options that include all -D's:
[code]
$ CC -g -v -xarch=amd64 a.cc
###command line files and options (expanded):
### -g -v -xarch=amd64 a.cc
### CC: Note: NLSPATH = /opt/SUNWspro/prod/bin/../lib/locale/%L/LC_MESSAGES/%N.cat:/opt/SUNWspro/prod/b in/../../lib/locale/%L/LC_MESSAGES/%N.cat
/opt/SUNWspro/prod/bin/ccfe -y-o -ya.o -y-fbe -y/opt/SUNWspro/prod/bin/fbe
-y-xarch=amd64 -xarch=amd64
<skip>
-D__SunOS_5_10 -D__SUNPRO_CC=0x580 -Dunix -Dsun -D__x86_64 -D__x86_64__
-D__amd64 -D__amd64__ -D__unix -D__sun
-D__BUILTIN_VA_STRUCT -D__SVR4 -D__SUNPRO_CC_COMPAT=5 -g
<skip>
/tmp/ccfe.21295.0.s >&/tmp/ccfe.21295.1.err
[/code]
# 2
The workaround for this is to configure your makefile, so that when itpasses -xtarget=ultra4 it also passes -DTARGET_ARCH=ultra4.Then your source code can test for TARGET_ARCH=ultra4--chris
# 3
Adding yet another define to the Makefile is only a workaround and not really 'user friendly'. In fact this method is quite error prone, and I'd rather see the compiler defining a macro I could use. Bernd
# 4
I understand what you're saying, and I'm not trying to argue with you.
I agree it would be more convenient if the compiler defined those symbols
for you. However, I think it is not error prone to update the Makefile.
Your makefile must already have something like this:
XX_FLAGS_ULTRA3 = -xchip=ultra3
XX_FLAGS_ULTRA4 = -xchip=ultra4
I am only suggesting to update these settings like this:
XX_FLAGS_ULTRA3 = -xchip=ultra3 -DCHIP=ultra3
XX_FLAGS_ULTRA4 = -xchip=ultra4 -DCHIP=ultra4
If your Makefile was able to ignore the chip values, then I agree
it would be a big increase in complexity to add new -D options.
But because it must already be controlling -xchip, it doesn't seem
like a difficult workaround to add control for new -D options to
the same part of the Makefile.
# 5
> If your Makefile was able to ignore the chip values,
> then I agree
> it would be a big increase in complexity to add new
> -D options.
> But because it must already be controlling -xchip, it
> doesn't seem
> like a difficult workaround to add control for new -D
> options to
> the same part of the Makefile.
There are two scenarios:
a) compiling for the native platform: here I am usually using something like
CHIP = -`fpversion -foption`
in the Makefile - so here a compiler defined macro would really be helpful, because
I don't know beforehand the result of fpversion.
b) cross-compiling: There I can't use fpversion, so your apprcach could be applied.
However, the compiler defined macro would also be useful here.
Furthermore, a compiler defined macro would set a kind of a "standard", all developers
could rely on, unlike user defined macros that are not consistent. Already in this thread
we have used at least 3 different macro names to do the same thing. ;-)
# 6
To get this functionality, you can submit an RFE (request for enhancement) at http://bugs.sun.com/services/bugreport/index.jsp
