Re: [Minios-devel] [UNIKRAFT PATCHv4 05/43] build: Add a makefile function to check GCC version

[Wei Chen <Wei.Chen@xxxxxxx>]

Hi Simon,

> -----Original Message-----
> From: Simon Kuenzer <simon.kuenzer@xxxxxxxxx>
> Sent: 2018年7月10日 21:52
> To: Wei Chen <Wei.Chen@xxxxxxx>; minios-devel@xxxxxxxxxxxxxxxxxxxx
> Cc: Kaly Xin <Kaly.Xin@xxxxxxx>; nd <nd@xxxxxxx>
> Subject: Re: [Minios-devel] [UNIKRAFT PATCHv4 05/43] build: Add a makefile
> function to check GCC version
> 
> I just noticed that this check is not working if you compare 4.9 (older)
> with 4.10 (newer) because 4.10 is considered as the floating point
> number 4.1 by `bc`. As fix we probably should do two individual checks:
> (1) major and then (2) minor.
> Btw, do you think you could provide a version that does not need `bc`? I
> rather prefer something that requires the least possible tools installed
> on the system. My concern is that we can't assume `bc` is installed as a
> standard tool. But maybe I am wrong with this concern. What do you think?
> 

Yes, it's possible. I have done a new method to use BASH only,
No bc, expr, let or ETC required. I will send it with next version.

> On 06.07.2018 11:03, Wei Chen wrote:
> > In this patch, we add a test_gcc_version function to test GCC
> > version and return a result. In this case, this function can
> > be used not only for processor flags check, but also can be
> > used in other places of Unikraft.
> >
> > Signed-off-by: Wei Chen <Wei.Chen@xxxxxxx>
> > ---
> >   Makefile                     | 4 ++++
> >   support/build/Makefile.rules | 5 +++++
> >   2 files changed, 9 insertions(+)
> >
> > diff --git a/Makefile b/Makefile
> > index d10f53b..e133039 100644
> > --- a/Makefile
> > +++ b/Makefile
> > @@ -428,6 +428,10 @@ LIFTOFF                := liftoff -e -s
> >   override ARFLAGS:= rcs
> >   CC_VERSION        := $(shell $(CC) --version | \
> >                sed -n -r 's/^.* ([0-9]*)\.([0-9]*)\.([0-9]*)[ ]*.*/\1.\2/p')
> > +# Retrieve GCC major and minor number from CC_VERSION. They would be used
> > +# to select correct optimization parameters for target CPUs.
> > +CC_VER_MAJOR   := $(word 1,$(subst ., ,$(CC_VERSION)))
> > +CC_VER_MINOR   := $(word 2,$(subst ., ,$(CC_VERSION)))
> >
> >   ASFLAGS           += -DCC_VERSION=$(CC_VERSION)
> >   CFLAGS            += -DCC_VERSION=$(CC_VERSION)
> > diff --git a/support/build/Makefile.rules b/support/build/Makefile.rules
> > index e317e3d..d5372cd 100644
> > --- a/support/build/Makefile.rules
> > +++ b/support/build/Makefile.rules
> > @@ -29,6 +29,11 @@ lc = $(subst A,a,$(subst B,b,$(subst C,c,$(subst
> D,d,$(subst E,e,$(subst F,f,$(s
> >   # upper case
> >   uc = $(subst a,A,$(subst b,B,$(subst c,C,$(subst d,D,$(subst e,E,$(subst
> f,F,$(subst g,G,$(subst h,H,$(subst i,I,$(subst j,J,$(subst k,K,$(subst
> l,L,$(subst m,M,$(subst n,N,$(subst o,O,$(subst p,P,$(subst q,Q,$(subst
> r,R,$(subst s,S,$(subst t,T,$(subst u,U,$(subst v,V,$(subst w,W,$(subst
> x,X,$(subst y,Y,$(subst z,Z,$(1)))))))))))))))))))))))))))
> >
> > +# test whether GCC version meets the minimum requirement
> > +# test_gcc_version $gcc_major,$gcc_minor
> > +define test_gcc_version =
> > +$(shell echo 'if($(CC_VER_MAJOR).$(CC_VER_MINOR)>=$(1).$(2)) print "y"'| 
> > bc)
> > +endef
> >
> >
> ##############################################################################
> ##
> >   #
> >
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