|
1 Subject: AIX - Misc/AIX-NOTES |
|
2 From: Vladimir Marangozov <Vladimir.Marangozov@imag.fr> |
|
3 To: guido@CNRI.Reston.Va.US (Guido van Rossum) |
|
4 Date: Wed, 6 Aug 1997 11:41:00 +0200 (EET) |
|
5 |
|
6 ============================================================================== |
|
7 COMPILER INFORMATION |
|
8 ------------------------------------------------------------------------------ |
|
9 |
|
10 (1) A problem has been reported with "make test" failing because of "weird |
|
11 indentation." Searching the comp.lang.python newsgroup reveals several |
|
12 threads on this subject, and it seems to be a compiler bug in an old |
|
13 version of the AIX CC compiler. However, the compiler/OS combination |
|
14 which has this problem is not identified. In preparation for the 1.4 |
|
15 release, Vladimir Marangozov (Vladimir.Marangozov@imag.fr) and Manus Hand |
|
16 (mhand@csn.net) reported no such troubles for the following compilers and |
|
17 operating system versions: |
|
18 AIX C compiler version 3.1.2 on AIX 4.1.3 and AIX 4.1.4 |
|
19 AIX C compiler version 1.3.0 on AIX 3.2.5 |
|
20 If you have this problem, please report the compiler/OS version. |
|
21 |
|
22 (2) Stefan Esser (se@MI.Uni-Koeln.DE), in work done to compile Python |
|
23 1.0.0 on AIX 3.2.4, reports that AIX compilers don't like the LANG |
|
24 environment varaiable set to European locales. This makes the compiler |
|
25 generate floating point constants using "," as the decimal seperator, |
|
26 which the assembler doesn't understand (or perhaps it is the other way |
|
27 around, with the assembler expecting, but not getting "," in float |
|
28 numbers). "LANG=C; export LANG" solves the problem, as does |
|
29 "LANG=C $(MAKE) ..." in the master Makefile. |
|
30 |
|
31 (3) The cc (or xlc) compiler considers "Python/ceval.c" too complex to |
|
32 optimize, except when invoked with "-qmaxmem=4000" |
|
33 |
|
34 (4) Some problems (due to _AIX not being #defined) when python 1.0.0 was |
|
35 compiled using 'gcc -ansi' were reported by Stefan Esser, but were not |
|
36 investigated. |
|
37 |
|
38 (5) The cc compiler has internal variables named "__abs" and "__div". These |
|
39 names are reserved and may not be used as program variables in compiled |
|
40 source. (As an anecdote in support of this, the implementation of |
|
41 Python/operator.c had this problem in the 1.4 beta releases, and the |
|
42 solution was to re#define some core-source variables having these names, |
|
43 to give these python variables different names if the build is being done |
|
44 on AIX.) |
|
45 |
|
46 (6) As mentioned in the README, builds done immediately after previous builds |
|
47 (without "make clean" or "make clobber") sometimes fail for mysterious |
|
48 reasons. There are some unpredictable results when the configuration |
|
49 is changed (that is, if you "configure" with different parameters) or if |
|
50 intermediate changes are made to some files. Performing "make clean" or |
|
51 "make clobber" resolves the problems. |
|
52 |
|
53 ============================================================================== |
|
54 THREAD SUPPORT |
|
55 ------------------------------------------------------------------------------ |
|
56 |
|
57 As of AIX version 4, there are two (incompatible) types of pthreads on AIX: |
|
58 a) AIX DCE pthreads (on AIX 3.2.5) |
|
59 b) AIX 4 pthreads (on AIX 4.1 and up) |
|
60 Support has been added to Python to handle the distinction. |
|
61 |
|
62 The cc and gcc compilers do not initialize pthreads properly. The only |
|
63 compilers that can initialize pthreads properly are IBM *_r* compilers, |
|
64 which use the crt0_r.o module, and which invoke ld with the reentrant |
|
65 version of libc (libc_r). |
|
66 |
|
67 In order to enable thread support, follow these steps: |
|
68 1. Uncomment the thread module in Modules/Setup |
|
69 2. configure --without-gcc --with-thread ... |
|
70 3. make CC="cc_r" OPT="-O -qmaxmem=4000" |
|
71 |
|
72 For example, to make with both threads and readline, use: |
|
73 ./configure --without-gcc --with-thread --with-readline=/usr/local/lib |
|
74 make CC=cc_r OPT="-O2 -qmaxmem=4000" |
|
75 |
|
76 If the "make" which is used ignores the "CC=cc_r" directive, one could alias |
|
77 the cc command to cc_r (for example, in C-shell, perform an "alias cc cc_r"). |
|
78 |
|
79 Vladimir Marangozov (Vladimir.Marangozov@imag.fr) provided this information, |
|
80 and he reports that a cc_r build initializes threads properly and that all |
|
81 demos on threads run okay with cc_r. |
|
82 |
|
83 ============================================================================== |
|
84 SHARED LIBRARY SUPPORT |
|
85 ------------------------------------------------------------------------------ |
|
86 |
|
87 AIX shared library support was added to Python in the 1.4 release by Manus |
|
88 Hand (mhand@csn.net) and Vladimir Marangozov (Vladimir.Marangozov@imag.fr). |
|
89 |
|
90 Python modules may now be built as shared libraries on AIX using the normal |
|
91 process of uncommenting the "*shared*" line in Modules/Setup before the |
|
92 build. |
|
93 |
|
94 AIX shared libraries require that an "export" and "import" file be provided |
|
95 at compile time to list all extern symbols which may be shared between |
|
96 modules. The "export" file (named python.exp) for the modules and the |
|
97 libraries that belong to the Python core is created by the "makexp_aix" |
|
98 script before performing the link of the python binary. It lists all global |
|
99 symbols (exported during the link) of the modules and the libraries that |
|
100 make up the python executable. |
|
101 |
|
102 When shared library modules (.so files) are made, a second shell script |
|
103 is invoked. This script is named "ld_so_aix" and is also provided with |
|
104 the distribution in the Modules subdirectory. This script acts as an "ld" |
|
105 wrapper which hides the explicit management of "export" and "import" files; |
|
106 it adds the appropriate arguments (in the appropriate order) to the link |
|
107 command that creates the shared module. Among other things, it specifies |
|
108 that the "python.exp" file is an "import" file for the shared module. |
|
109 |
|
110 At the time of this writing, neither the python.exp file nor the makexp_aix |
|
111 or ld_so_aix scripts are installed by the make procedure, so you should |
|
112 remember to keep these and/or copy them to a different location for |
|
113 safekeeping if you wish to use them to add shared extension modules to |
|
114 python. However, if the make process has been updated since this writing, |
|
115 these files MAY have been installed for you during the make by the |
|
116 LIBAINSTALL rule, in which case the need to make safe copies is obviated. |
|
117 |
|
118 If you wish to add a shared extension module to the language, you would follow |
|
119 the steps given in the example below (the example adds the shared extension |
|
120 module "spam" to python): |
|
121 1. Make sure that "ld_so_aix" and "makexp_aix" are in your path. |
|
122 2. The "python.exp" file should be in the current directory. |
|
123 3. Issue the following commands or include them in your Makefile: |
|
124 cc -c spammodule.c |
|
125 ld_so_aix cc spammodule.o -o spammodule.so |
|
126 |
|
127 For more detailed information on the shared library support, examine the |
|
128 contents of the "ld_so_aix" and "makexp_aix" scripts or refer to the AIX |
|
129 documentation. |
|
130 |
|
131 NOTE: If the extension module is written in C++ and contains templates, |
|
132 an alternative to "ld_so_aix" is the /usr/lpp/xlC/bin/makeC++SharedLib |
|
133 script. Chris Myers (myers@TC.Cornell.EDU) reports that ld_so_aix |
|
134 works well for some C++ (including the C++ that is generated |
|
135 automatically by the Python SWIG package [SWIG can be found at |
|
136 http://www.cs.utah.edu/~beazley/SWIG/swig.html]). However, it is not |
|
137 known whether makeC++SharedLib can be used as a complete substitute |
|
138 for ld_so_aix. |
|
139 |
|
140 According to Gary Hook from IBM, the format of the export file changed |
|
141 in AIX 4.2. For AIX 4.2 and later, a period "." is required on the |
|
142 first line after "#!". If python crashes while importing a shared |
|
143 library, you can try modifying the LINKCC variable in the Makefile. |
|
144 It probably looks like this: |
|
145 |
|
146 LINKCC= $(srcdir)/Modules/makexp_aix Modules/python.exp \"\" $(LIBRARY); $(PURIFY) $(CXX) |
|
147 |
|
148 You should modify the \"\" to be a period: |
|
149 |
|
150 LINKCC= $(srcdir)/Modules/makexp_aix Modules/python.exp . $(LIBRARY); $(PURIFY) $(CXX) |
|
151 |
|
152 Using a period fixed the problem in the snake farm. YMMV. |
|
153 This fix has been incorporated into Python 2.3. |
|
154 |
|
155 ============================================================================== |