Re: 'guix build --target=' handling questions

[Ludovic Courtès]

Sergei Trofimovich  skribis:

> About the 'guix environment --target=' / 'guix build --target=' part or 
> question:
>
> Would it make sense to have '--target=' support in 'guix environment' tool or 
> is it
> too tricky?

I think it would make sense (at least without --ad-hoc) and shouldn’t be
too tricky.  You can file it on bug-guix so we remember!

Ludo’.

Re: 'guix build --target=' handling questions

[Sergei Trofimovich]

On Mon, 06 Mar 2017 17:04:18 +0100
l...@gnu.org (Ludovic Courtès) wrote:

> Sergei Trofimovich  skribis:
> 
> >> Question time:
> >> 
> >> - Is there a way to run 'guix environment --target=' in the same way as 
> >> 'guix build --target='
> >>   sets it up? I'd like to see how both compilers are supposed to be 
> >> present in there.
> >>
> >> - Why default g++ in PATH is the host g++ and not target g++?
> >>   Target seems to make most sense if no explicit compiler is specified.
> >> 
> >> - How to actually set CXX to point to target g++?
> >>   It looks like implicitly there already both host (through native-inputs)
> >>   and target (through build-inputs) compilers available.
> >>   I would expect something like
> >>   #:make-flags (list (string-append "CXX=" <.?.>)) 
> >>   What should be in place of that "<.?.>" to refer to target g++?  
> >
> > I think I've found a workaround at least for my third question.
> >
> > Both host and target compilers are available as g++ and ${target}-g++.
> >
> > Thus the following workaround seems to work:
> >
> > diff --git a/gnu/packages/regex.scm b/gnu/packages/regex.scm
> > index f04cba706..a8fa689ab 100644
> > --- a/gnu/packages/regex.scm
> > +++ b/gnu/packages/regex.scm
> > @@ -20,11 +20,13 @@
> >
> >  (define-module (gnu packages regex)
> >#:use-module ((guix licenses) #:prefix license:)
> >#:use-module (guix packages)
> >#:use-module (guix download)
> > -  #:use-module (guix build-system gnu))
> > +  #:use-module (guix build-system gnu)
> > +  #:use-module (guix utils) ; for %current-target-system
> > +  )
> >
> >  (define-public re2
> > (package
> >   (name "re2")
> >   (version "2017-01-01")
> > @@ -40,11 +42,15 @@
> >   "0yij1ajh66h3pj3kfz7y0ldrsww8rlpjzaavyr5lchl98as1jq74"
> >   (build-system gnu-build-system)
> >   (arguments
> >`(#:test-target "test"
> >  ;; There is no configure step, but the Makefile respects a prefix.
> > -#:make-flags (list (string-append "prefix=" %output))
> > +#:make-flags (list (string-append "prefix=" %output)
> > +   (string-append "CXX=" ,(string-append (if 
> > (%current-target-system)
> > + 
> > (string-append (%current-target-system) "-")
> > + "")
> > + "g++")))  
> 
> As John wrote, this is the right fix for this package.

Aha!

> If you can send it with ‘git send-email’ (see
> ),

Sent as:
http://debbugs.gnu.org/cgi/bugreport.cgi?bug=26004

About the 'guix environment --target=' / 'guix build --target=' part or 
question:

Would it make sense to have '--target=' support in 'guix environment' tool or 
is it
too tricky?

Thanks!

-- 

  Sergei


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Description: Цифровая подпись OpenPGP

Re: 'guix build --target=' handling questions

[Ludovic Courtès]

Sergei Trofimovich  skribis:

>> Question time:
>> 
>> - Is there a way to run 'guix environment --target=' in the same way as 
>> 'guix build --target='
>>   sets it up? I'd like to see how both compilers are supposed to be present 
>> in there.
>>
>> - Why default g++ in PATH is the host g++ and not target g++?
>>   Target seems to make most sense if no explicit compiler is specified.
>> 
>> - How to actually set CXX to point to target g++?
>>   It looks like implicitly there already both host (through native-inputs)
>>   and target (through build-inputs) compilers available.
>>   I would expect something like
>>   #:make-flags (list (string-append "CXX=" <.?.>)) 
>>   What should be in place of that "<.?.>" to refer to target g++?
>
> I think I've found a workaround at least for my third question.
>
> Both host and target compilers are available as g++ and ${target}-g++.
>
> Thus the following workaround seems to work:
>
> diff --git a/gnu/packages/regex.scm b/gnu/packages/regex.scm
> index f04cba706..a8fa689ab 100644
> --- a/gnu/packages/regex.scm
> +++ b/gnu/packages/regex.scm
> @@ -20,11 +20,13 @@
>
>  (define-module (gnu packages regex)
>#:use-module ((guix licenses) #:prefix license:)
>#:use-module (guix packages)
>#:use-module (guix download)
> -  #:use-module (guix build-system gnu))
> +  #:use-module (guix build-system gnu)
> +  #:use-module (guix utils) ; for %current-target-system
> +  )
>
>  (define-public re2
> (package
>   (name "re2")
>   (version "2017-01-01")
> @@ -40,11 +42,15 @@
>   "0yij1ajh66h3pj3kfz7y0ldrsww8rlpjzaavyr5lchl98as1jq74"
>   (build-system gnu-build-system)
>   (arguments
>`(#:test-target "test"
>  ;; There is no configure step, but the Makefile respects a prefix.
> -#:make-flags (list (string-append "prefix=" %output))
> +#:make-flags (list (string-append "prefix=" %output)
> +   (string-append "CXX=" ,(string-append (if 
> (%current-target-system)
> + 
> (string-append (%current-target-system) "-")
> + "")
> + "g++")))

As John wrote, this is the right fix for this package.

If you can send it with ‘git send-email’ (see
),
I’ll apply it right away.  Otherwise I can do it on your behalf.

Thanks!

Ludo’.

Re: 'guix build --target=' handling questions

[John Darrington]

On Wed, Feb 22, 2017 at 10:54:22PM +, Sergei Trofimovich wrote:
 
  (define-module (gnu packages regex)
#:use-module ((guix licenses) #:prefix license:)
#:use-module (guix packages)
#:use-module (guix download)
 -  #:use-module (guix build-system gnu))
 +  #:use-module (guix build-system gnu)
 +  #:use-module (guix utils) ; for %current-target-system
 +  )
 
  (define-public re2
 (package
   (name "re2")
   (version "2017-01-01")
 @@ -40,11 +42,15 @@
   
"0yij1ajh66h3pj3kfz7y0ldrsww8rlpjzaavyr5lchl98as1jq74"
   (build-system gnu-build-system)
   (arguments
`(#:test-target "test"
  ;; There is no configure step, but the Makefile respects a prefix.
 -#:make-flags (list (string-append "prefix=" %output))
 +#:make-flags (list (string-append "prefix=" %output)
 +   (string-append "CXX=" ,(string-append (if 
(%current-target-system)
 + 
(string-append (%current-target-system) "-")
 + "")
 + "g++")))
  #:phases
  (modify-phases %standard-phases
(delete 'configure)
(add-after 'install 'delete-static-library
  (lambda* (#:key outputs #:allow-other-keys)
 
 It looks clumsy and potentially requires more tools to be wrapped like 
that.
 
 At least 'ar' for this package. Perhaps there is a function that already
 adds a "${target}-" and I've missed it?
 

So far as I'm aware there is no better solution than what you have proposed.  
It is a common
problem for packages which don't provide a proper autoconf ./configure script.

J'



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Re: 'guix build --target=' handling questions

[Sergei Trofimovich]

> Question time:
> 
> - Is there a way to run 'guix environment --target=' in the same way as 'guix 
> build --target='
>   sets it up? I'd like to see how both compilers are supposed to be present 
> in there.
>
> - Why default g++ in PATH is the host g++ and not target g++?
>   Target seems to make most sense if no explicit compiler is specified.
> 
> - How to actually set CXX to point to target g++?
>   It looks like implicitly there already both host (through native-inputs)
>   and target (through build-inputs) compilers available.
>   I would expect something like
>   #:make-flags (list (string-append "CXX=" <.?.>)) 
>   What should be in place of that "<.?.>" to refer to target g++?

I think I've found a workaround at least for my third question.

Both host and target compilers are available as g++ and ${target}-g++.

Thus the following workaround seems to work:

diff --git a/gnu/packages/regex.scm b/gnu/packages/regex.scm
index f04cba706..a8fa689ab 100644
--- a/gnu/packages/regex.scm
+++ b/gnu/packages/regex.scm
@@ -20,11 +20,13 @@

 (define-module (gnu packages regex)
   #:use-module ((guix licenses) #:prefix license:)
   #:use-module (guix packages)
   #:use-module (guix download)
-  #:use-module (guix build-system gnu))
+  #:use-module (guix build-system gnu)
+  #:use-module (guix utils) ; for %current-target-system
+  )

 (define-public re2
(package
  (name "re2")
  (version "2017-01-01")
@@ -40,11 +42,15 @@
  "0yij1ajh66h3pj3kfz7y0ldrsww8rlpjzaavyr5lchl98as1jq74"
  (build-system gnu-build-system)
  (arguments
   `(#:test-target "test"
 ;; There is no configure step, but the Makefile respects a prefix.
-#:make-flags (list (string-append "prefix=" %output))
+#:make-flags (list (string-append "prefix=" %output)
+   (string-append "CXX=" ,(string-append (if 
(%current-target-system)
+ 
(string-append (%current-target-system) "-")
+ "")
+ "g++")))
 #:phases
 (modify-phases %standard-phases
   (delete 'configure)
   (add-after 'install 'delete-static-library
 (lambda* (#:key outputs #:allow-other-keys)

It looks clumsy and potentially requires more tools to be wrapped like that.

At least 'ar' for this package. Perhaps there is a function that already
adds a "${target}-" and I've missed it?

-- 

  Sergei


pgpaAoEdth0Gv.pgp
Description: Цифровая подпись OpenPGP

'guix build --target=' handling questions

[Sergei Trofimovich]

Hia!

Before asking my questions I'll setup the scene first.

The scene:

I'm playing with cross-compiler support in guix.

[ x86_64 -> alpha target as an example with
  this tiny patch: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=25799 ]

I've stumbled upon the two cases: working[1] and non-working[2].

[1] working:
  $ ./pre-inst-env guix build --check re2c --target=alpha-unknown-linux-gnu 
--no-grafts
  ...
  /gnu/store/15ibxf5xzcqzfx0xgb5s6qa5z2ah3avg-re2c-0.16
  $ file /gnu/store/15ibxf5xzcqzfx0xgb5s6qa5z2ah3avg-re2c-0.16/bin/re2c 
  /gnu/store/15ibxf5xzcqzfx0xgb5s6qa5z2ah3avg-re2c-0.16/bin/re2c: ELF 64-bit 
LSB executable,
Works as expected.

[2] non-working:
  $ ./pre-inst-env guix build --check re2 --target=alpha-unknown-linux-gnu 
--no-grafts
  ...
  /gnu/store/mg474j0gx56fdl6wrpaxxxwsdknl7k2i-re2-2017-01-01
  $ file 
/gnu/store/mg474j0gx56fdl6wrpaxxxwsdknl7k2i-re2-2017-01-01/lib/libre2.so.0.0.0 
  
/gnu/store/mg474j0gx56fdl6wrpaxxxwsdknl7k2i-re2-2017-01-01/lib/libre2.so.0.0.0: 
ELF 64-bit LSB shared object, x86-64

It seems that re2 derivation ignores --target
and builds it's library with host compiler, not target compiler.

Relevant re2 package snippet from
http://git.savannah.gnu.org/cgit/guix.git/tree/gnu/packages/regex.scm#n27

 (build-system gnu-build-system)
 (arguments
  `(#:test-target "test"
;; There is no configure step, but the Makefile respects a prefix.
#:make-flags (list (string-append "prefix=" %output))
#:phases
(modify-phases %standard-phases
  (delete 'configure)

As we see here definition skips ./configure step (that's ok)
and does not pass CXX=${target}-g++ to make flag.

I wonder what are the possible options to override CXX here?

Makefile for re2 is very straightforward:
CXX?=g++
...
obj/%.o: %.cc $(HFILES)
@mkdir -p $$(dirname $@)
$(CXX) -c -o $@ $(CPPFLAGS) $(RE2_CXXFLAGS) $(CXXFLAGS) -DNDEBUG $*.cc
...
obj/so/libre2.$(SOEXT): $(SOFILES)
@mkdir -p obj/so
$(MAKE_SHARED_LIBRARY) -o obj/so/libre2.$(SOEXTVER) $(SOFILES)
ln -sf libre2.$(SOEXTVER) $@

Question time:

- Is there a way to run 'guix environment --target=' in the same way as 'guix 
build --target='
  sets it up? I'd like to see how both compilers are supposed to be present in 
there.

- Why default g++ in PATH is the host g++ and not target g++?
  Target seems to make most sense if no explicit compiler is specified.

- How to actually set CXX to point to target g++?
  It looks like implicitly there already both host (through native-inputs)
  and target (through build-inputs) compilers available.
  I would expect something like
  #:make-flags (list (string-append "CXX=" <.?.>)) 
  What should be in place of that "<.?.>" to refer to target g++?

Thank you!

-- 

  Sergei


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