Re: [Xen-devel] [PATCH v2 3/4] python: set absolute path to libxl.h on _pyxl_types.c

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

Ian Campbell wrote:
> On Thu, 2012-05-17 at 15:02 +0100, Roger Pau Monne wrote:
> > Ian Campbell wrote:
> > > On Thu, 2012-05-17 at 13:16 +0100, Roger Pau Monne wrote:
> > > > genwrap.py generates _pyxl_types.c, which includes libxl.h, but if
> > > > libxl.h is already present in the include search path, the old one was
> > > > included instead of the new one, giving compilation errors. Since
> > > > _pyxl_types.c is generated at compilation time, we can safely set
> > > > the path to libxl.h include.
> > > >
> > > > I've only experienced this problem when compiling Xen on NetBSD with
> > > > old header files in the include path, Linux seems to not have this
> > > > problem.
> > > Should this be include<>   and not "", since libxl.h isn't in the current
> > > dir in this case?
> > >
> > > Is the right fix to make sure that the in-tree -I lines come first?
> > > Ian.
> > Actually I'm not sure if it's possible to make sure the in-tree -I lines
> > come first, because the gcc options are automatically generated by
> > python build tools (distutils&  friends...), so we cannot touch much of
> > this (I've looked at distutils.core options, and it seems to be no way
> > of setting an order on compiler options, but I'm no expert on python C
> > extensions building), so unless we craft our own makefile to build this
> > python stuff I think we are stuck with something like this.
> Surely distutils puts user supplied options first before system options?
> My /usr/lib/python2.5/distutils/command/build_ext.py says:
>
>         # Put the Python "system" include dir at the end, so that
>          # any local include dirs take precedence.
>          self.include_dirs.append(py_include)
>          if plat_py_include != py_include:
>              self.include_dirs.append(plat_py_include)
>
> So it seems like this is the intention.
>
> Are you sure this isn't just a bug in your version of distutils or
> something like that?
>
> My python xl builds end up as:
>          building 'xl' extension
>          gcc -fno-strict-aliasing -DNDEBUG -g -fwrapv -O2 -Wall
>          -Wstrict-prototypes -O1 -fno-omit-frame-pointer -m32 -march=i686
>          -g -fno-strict-aliasing -std=gnu99 -Wall -Wstrict-prototypes
>          -Wdeclaration-after-statement -D__XEN_TOOLS__ -MMD -MF .build.d
>          -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE
>          -D_LARGEFILE64_SOURCE -fno-optimize-sibling-calls
>          -mno-tls-direct-seg-refs -fPIC -I../../tools/include
>          -I../../tools/libxl -I../../tools/libxc -Ixen/lowlevel/xl
>          -I/usr/include/python2.6 -c xen/lowlevel/xl/xl.c -o
>          build/temp.linux-i686-2.6/xen/lowlevel/xl/xl.o
>          -fno-strict-aliasing -Werror
>
> Which has our local -I options before all the others -- which is
> sensible. What do you see with your system?
This is what I see:

CC="gcc" CFLAGS="-O1 -fno-omit-frame-pointer -m64 -g 
-fno-strict-aliasing -std=gnu99 -Wall -Wstrict-prototypes 
-Wdeclaration-after-statement   -D__XEN_TOOLS__ -MMD -MF .build.d 
-fno-optimize-sibling-calls" python2.7 setup.py build
running build
running build_py
running build_ext
building 'xl' extension

gcc -DNDEBUG -O2 -DHAVE_DB_185_H -I/usr/include -I/usr/pkg/include -O1 
-fno-omit-frame-pointer -m64 -g -fno-strict-aliasing -std=gnu99 -Wall 
-Wstrict-prototypes -Wdeclaration-after-statement -D__XEN_TOOLS__ -MMD 
-MF .build.d -fno-optimize-sibling-calls -fPIC -I../../tools/include 
-I../../tools/libxl -I../../tools/libxc -Ixen/lowlevel/xl 
-I/usr/pkg/include/python2.7 -c xen/lowlevel/xl/_pyxl_types.c -o 
build/temp.netbsd-6.0_BETA-amd64-2.7/xen/lowlevel/xl/_pyxl_types.o 
-fno-strict-aliasing -Werror
xen/lowlevel/xl/_pyxl_types.c: In function 'genwrap__init':
xen/lowlevel/xl/_pyxl_types.c:4346:78: error: 
'LIBXL_EVENT_TYPE_DOMAIN_CREATE_CONSOLE_AVAILABLE' undeclared (first use 
in this function)
xen/lowlevel/xl/_pyxl_types.c:4346:78: note: each undeclared identifier 
is reported only once for each function it appears in
error: command 'gcc' failed with exit status 1
gmake: *** [build] Error 1
gmake: Leaving directory `/root/xen/xen-netbsd/tools/python'

So this part "-DNDEBUG -O2 -DHAVE_DB_185_H -I/usr/include 
-I/usr/pkg/include" comes even before our passed CFLAGS.
My /usr/pkg/lib/python2.7/distutils/command/build_ext.py:

        # Put the Python "system" include dir at the end, so that
        # any local include dirs take precedence.
        self.include_dirs.append(py_include)
        if plat_py_include != py_include:
            self.include_dirs.append(plat_py_include)

        [...]


        # Finally add the user include and library directories if requested
        if self.user:
            user_include = os.path.join(USER_BASE, "include")
            user_lib = os.path.join(USER_BASE, "lib")
            if os.path.isdir(user_include):
                self.include_dirs.append(user_include)
            if os.path.isdir(user_lib):
                self.library_dirs.append(user_lib)
                self.rpath.append(user_lib)

So it says it puts them at the end, but it doesn't do so. I've looked at 
Python 2.7 original source, and this is not a NetBSD port specific bug.
> Ian.

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