155 lines
8.2 KiB
Plaintext
155 lines
8.2 KiB
Plaintext
Subject: AIX-NOTES FOR 1.4
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From: Manus Hand <Manus.Hand@evolving.com>
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To: guido@CNRI.Reston.VA.US
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cc: Vladimir.Marangozov@imag.fr
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Date: Fri, 25 Oct 1996 15:19:23 -0600 (MDT)
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==============================================================================
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COMPILER INFORMATION
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------------------------------------------------------------------------------
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(1) A problem has been reported with "make test" failing because of "weird
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indentation." Searching the comp.lang.python newsgroup reveals several
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threads on this subject, and it seems to be a compiler bug in an old
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version of the AIX CC compiler. However, the compiler/OS combination
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which has this problem is not identified. In preparation for the 1.4
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release, Vladimir Marangozov (Vladimir.Marangozov@imag.fr) and Manus Hand
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(mhand@csn.net) reported no such troubles for the following compilers and
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operating system versions:
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AIX C compiler version 3.1.2 on AIX 4.1.3 and AIX 4.1.4
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AIX C compiler version 1.3.0 on AIX 3.2.5
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If you have this problem, please report the compiler/OS version.
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[Postscript: it has also been spotted on AIX 4.2.1 --Guido]
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(2) Stefan Esser (se@MI.Uni-Koeln.DE), in work done to compile Python
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1.0.0 on AIX 3.2.4, reports that AIX compilers don't like the LANG
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environment varaiable set to European locales. This makes the compiler
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generate floating point constants using "," as the decimal seperator,
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which the assembler doesn't understand (or perhaps it is the other way
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around, with the assembler expecting, but not getting "," in float
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numbers). "LANG=C; export LANG" solves the problem, as does
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"LANG=C $(MAKE) ..." in the master Makefile.
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(3) The cc (or xlc) compiler considers "Python/ceval.c" too complex to
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optimize, except when invoked with "-qmaxmem=4000"
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(4) Some problems (due to _AIX not being #defined) when python 1.0.0 was
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compiled using 'gcc -ansi' were reported by Stefan Esser, but were not
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investigated.
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(5) The cc compiler has internal variables named "__abs" and "__div". These
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names are reserved and may not be used as program variables in compiled
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source. (As an anecdote in support of this, the implementation of
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Python/operator.c had this problem in the 1.4 beta releases, and the
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solution was to re#define some core-source variables having these names,
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to give these python variables different names if the build is being done
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on AIX.)
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(6) As mentioned in the README, builds done immediately after previous builds
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(without "make clean" or "make clobber") sometimes fail for mysterious
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reasons. There are some unpredictable results when the configuration
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is changed (that is, if you "configure" with different parameters) or if
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intermediate changes are made to some files. Performing "make clean" or
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"make clobber" resolves the problems.
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==============================================================================
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THREAD SUPPORT
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------------------------------------------------------------------------------
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AIX uses pthreads. However, as of AIX version 4, there are two (incompatible)
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types of pthreads on AIX:
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a) AIX DCE pthreads (on AIX 3.2.5)
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b) AIX 4 pthreads (on AIX 4.1 and up)
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Support has been added to Python to handle the distinction.
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The cc and gcc compilers do not initialize pthreads properly. The only
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compilers that can initialize pthreads properly are IBM *_r* compilers,
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which use the crt0_r.o module, and which invoke ld with the reentrant
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version of libc (libc_r).
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In order to enable thread support, follow these steps:
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1. Uncomment the thread module in Modules/Setup
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2. configure --without-gcc --with-thread ...
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3. make CC="cc_r" OPT="-O -qmaxmem=4000"
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For example, to make with both threads and readline, use:
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./configure --without-gcc --with-thread --with-readline=/usr/local/lib
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make CC=cc_r OPT="-O2 -qmaxmem=4000"
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If the "make" which is used ignores the "CC=cc_r" directive, one could alias
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the cc command to cc_r (for example, in C-shell, perform an "alias cc cc_r").
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Vladimir Marangozov (Vladimir.Marangozov@imag.fr) provided this information,
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and he reports that a cc_r build initializes threads properly and that all
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demos on threads run okay with cc_r.
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==============================================================================
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SHARED LIBRARY SUPPORT
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------------------------------------------------------------------------------
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AIX shared library support was added to Python in the 1.4 release by Manus
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Hand (mhand@csn.net) and Vladimir Marangozov (Vladimir.Marangozov@imag.fr).
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Python modules may now be built as shared libraries on AIX using the normal
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process of uncommenting the "*shared*" line in Modules/Setup.in before the
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build. There is one additional step required, and that is to also uncomment
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the line in Modules/Setup.in which reads
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LINKCC= makexp_aix python.exp "" $(MYLIBS) $(ADDOBJS) ; $(CC)
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AIX shared libraries require that an "export" and "import" file be provided
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at compile time to list all extern symbols which may be shared between
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modules. The effect of uncommenting the LINKCC line in Modules/Setup.in is
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to create the "export" file for the modules and the libraries that belong to
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the Python core. This is done by the "makexp_aix" script, which creates a
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file named python.exp before performing the link of the python binary.
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When shared library modules (.so files) are made, a second shell script
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is invoked. This script is named "ld_so_aix" and is also provided with
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the distribution in the Modules subdirectory. This script acts as an "ld"
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wrapper which hides the explicit management of "export" and "import" files;
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it adds the appropriate arguments (in the appropriate order) to the link
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command that creates the shared module. Among other things, it specifies
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that the "python.exp" file is an "import" file for the shared module.
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A default python.exp file is provided with the distribution. It will be
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overwritten (by the action of the makexp_aix script) if you build with shared
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libraries. The python.exp file which comes with the distribution contains
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all extern symbols of a completely statically built python executable.
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Any python.exp file which is created from a build of python with some of the
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modules linked as shared modules will obviously not list symbols from the now
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dynamic modules. The distributed python.exp is provided so that, with
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assistance from the ld_so_aix and makexp_aix scripts, shared extension
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modules may be added to an otherwise completely static python build.
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At the time of this writing, neither the python.exp file nor the makexp_aix
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or ld_so_aix scripts are installed by the make procedure, so you should
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remember to keep these and/or copy them to a different location for
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safekeeping if you wish to use them to add shared extension modules to
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python. However, if the make process has been updated since this writing,
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these files MAY have been installed for you during the make by the
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LIBAINSTALL rule, in which case the need to make safe copies is obviated.
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If you wish to add a shared extension module to the language, you would follow
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the steps given in the example below (the example adds the shared extension
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module "spam" to python):
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1. Make sure that "ld_so_aix" and "makexp_aix" are in your path.
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2. The "python.exp" file should be in the current directory.
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3. Issue the following commands or include them in your Makefile:
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cc -c spammodule.c
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ld_so_aix cc spammodule.o -o spammodule.so
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For more detailed information on the shared library support, examine the
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contents of the "ld_so_aix" and "makexp_aix" scripts or refer to the AIX
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documentation.
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NOTE: If the extension module is written in C++ and contains templates,
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an alternative to "ld_so_aix" is the /usr/lpp/xlC/bin/makeC++SharedLib
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script. Chris Myers (myers@TC.Cornell.EDU) reports that ld_so_aix
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works well for some C++ (including the C++ that is generated
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automatically by the Python SWIG package [SWIG can be found at
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http://www.cs.utah.edu/~beazley/SWIG/swig.html]). However, it is not
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known whether makeC++SharedLib can be used as a complete substitute
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for ld_so_aix.
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==============================================================================
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