gcc/boehm-gc/doc/README.Mac

Patrick Beard's Notes for building GC v4.12 with CodeWarrior Pro 2:
----------------------------------------------------------------------------
The current build environment for the collector is CodeWarrior Pro 2.
Projects for CodeWarrior Pro 2 (and for quite a few older versions)
are distributed in the file Mac_projects.sit.hqx. The project file
:Mac_projects:gc.prj builds static library versions of the collector.
:Mac_projects:gctest.prj builds the GC test suite.

Configuring the collector is still done by editing the files
:Mac_files:MacOS_config.h and :Mac_files:MacOS_Test_config.h.

Lars Farm's suggestions on building the collector:
----------------------------------------------------------------------------
Garbage Collection on MacOS - a manual 'MakeFile'
-------------------------------------------------

Project files and IDE's are great on the Macintosh, but they do have
problems when used as distribution media. This note tries to provide
porting instructions in pure TEXT form to avoid those problems. A manual
'makefile' if you like.

    GC version:     4.12a2
    Codewarrior:    CWPro1
    date:           18 July 1997

The notes may or may not apply to earlier or later versions of the
GC/CWPro. Actually, they do apply to earlier versions of both except that
until recently a project could only build one target so each target was a
separate project. The notes will most likely apply to future versions too.
Possibly with minor tweaks.

This is just to record my experiences. These notes do not mean I now
provide a supported port of the GC to MacOS. It works for me. If it works
for you, great. If it doesn't, sorry, try again...;-) Still, if you find
errors, please let me know.

    mailto:         lars.farm@ite.mh.se

    address:        Lars Farm
                    Krönvägen 33b
                    856 44 Sundsvall
                    Sweden

Porting to MacOS is a bit more complex than it first seems. Which MacOS?
68K/PowerPC? Which compiler? Each supports both 68K and PowerPC and offer a
large number of (unique to each environment) compiler settings. Each
combination of compiler/68K/PPC/settings require a unique combination of
standard libraries. And the IDE's does not select them for you. They don't
even check that the library is built with compatible setting and this is
the major source of problems when porting the GC (and otherwise too).

You will have to make choices when you configure the GC. I've made some
choices here, but there are other combinations of settings and #defines
that work too.

As for target settings the major obstacles may be:
- 68K Processor: check "4-byte Ints".
- PPC Processor: uncheck "Store Static Data in TOC".

What you need to do:
===================

1) Build the GC as a library
2) Test that the library works with 'test.c'.
3) Test that the C++ interface 'gc_cpp.cc/h' works with 'test_cpp.cc'.

1) The Libraries:
=================
I made one project with four targets (68K/PPC tempmem or appheap). One target
will suffice if you're able to decide which one you want. I wasn't...

Codewarrior allows a large number of compiler/linker settings. I used these:

Settings shared by all targets:
------------------------------
o Access Paths:
  - User Paths:   the GC folder
  - System Paths: {Compiler}:Metrowerks Standard Library:
                  {Compiler}:MacOS Support:Headers:
                  {Compiler}:MacOS Support:MacHeaders:
o C/C++ language:
  - inlining: normal
  - direct to SOM: off
  - enable/check: exceptions, RTTI, bool (and if you like pool strings)

PowerPC target settings
-----------------------
o Target Settings:
  - name of target
  - MacOS PPC Linker
o PPC Target
  - name of library
o C/C++ language
  - prefix file as described below
o PPC Processor
  - Struct Alignment: PowerPC
  - uncheck "Store Static Data in TOC" -- important!
    I don't think the others matter, I use full optimization and its ok
o PPC Linker
  - Factory Settings (SYM file with full paths, faster linking, dead-strip
    static init, Main: __start)


68K target settings
-------------------
o Target Settings:
  - name of target
  - MacOS 68K Linker
o 68K Target
  - name of library
  - A5 relative data
o C/C++ language
  - prefix file as described below
o 68K Processor
  - Code model: smart
  - Struct alignment: 68K
  - FP: SANE
  - enable 4-Byte Ints -- important!
    I don't think the others matter. I selected...
  - enable: 68020
  - enable: global register allocation
o IR Optimizer
  - enable: Optimize Space, Optimize Speed
    I suppose the others would work too, but haven't tried...
o 68K Linker
  - Factory Settings (New Style MacsBug,SYM file with full paths,
    A6 Frames, fast link, Merge compiler glue into segment 1,
    dead-strip static init)

Prefix Files to configure the GC sources
----------------------------------------
The Codewarrior equivalent of commandline compilers -DNAME=X is to use
prefix-files. A TEXT file that is automatically #included before the first byte
of every source file. I used these:

---- ( cut here ) ----  gc_prefix_tempmem.h     -- 68K and PPC -----
    #include "gc_prefix_common.h"
    #undef USE_TEMPORARY_MEMORY
    #define USE_TEMPORARY_MEMORY
---- ( cut here ) ----  gc_prefix_appmem.h      -- 68K and PPC -----
    #include "gc_prefix_common.h"
    #undef USE_TEMPORARY_MEMORY
//  #define USE_TEMPORARY_MEMORY

---- ( cut here ) ----  gc_prefix_common.h      --------------------
// gc_prefix_common.h
// ------------------
// Codewarrior prefix file to configure the GC libraries
//
//   prefix files are the Codewarrior equivalent of the
//   command line option -Dname=x frequently seen in makefiles

#if !__MWERKS__
  #error only tried this with Codewarrior
#endif

#if macintosh
  #define MSL_USE_PRECOMPILED_HEADERS 0
  #include <ansi_prefix.mac.h>
  #ifndef __STDC__
    #define __STDC__ 0
  #endif

  //  See list of #defines to configure the library in: 'MakeFile'
  //  see also README

  #define SILENT                // no collection messages. In case
                                // of trouble you might want this off
  #define ALL_INTERIOR_POINTERS // follows interior pointers.
//#define DONT_ADD_BYTE_AT_END  // disables the padding if defined.
//#define SMALL_CONFIG          // whether to use a smaller heap.
  #define NO_SIGNALS            // signals aren't real on the Macintosh.
  #define ATOMIC_UNCOLLECTABLE  // GC_malloc_atomic_uncollectable()

  // define either or none as per personal preference
  //   used in malloc.c
  #define REDIRECT_MALLOC GC_malloc
//#define REDIRECT_MALLOC GC_malloc_uncollectable
  // if REDIRECT_MALLOC is #defined make sure that the GC library
  // is listed before the ANSI/ISO libs in the Codewarrior
  // 'Link order' panel
//#define IGNORE_FREE

  // mac specific configs
//#define USE_TEMPORARY_MEMORY    // use Macintosh temporary memory.
//#define SHARED_LIBRARY_BUILD    // build for use in a shared library.

#else
  // could build Win32 here too, or in the future
  // Rhapsody PPC-mach, Rhapsody PPC-MacOS,
  // Rhapsody Intel-mach, Rhapsody Intel-Win32,...
  // ... ugh this will get messy ...
#endif

// make sure ints are at least 32-bit
// ( could be set to 16-bit by compiler settings (68K) )

struct gc_private_assert_intsize_{ char x[ sizeof(int)>=4 ? 1 : 0 ]; };

#if __powerc
  #if __option(toc_data)
    #error turn off "store static data in TOC" when using GC
    //     ... or find a way to add TOC to the root set...(?)
  #endif
#endif
---- ( cut here ) ----  end of gc_prefix_common.h  -----------------

Files to  build the GC libraries:
--------------------------------
    allchblk.c
    alloc.c
    blacklst.c
    checksums.c
    dbg_mlc.c
    finalize.c
    headers.c
    mach_dep.c
    MacOS.c    -- contains MacOS code
    malloc.c
    mallocx.c
    mark.c
    mark_rts.c
    misc.c
    new_hblk.c
    obj_map.c
    os_dep.c   -- contains MacOS code
    ptr_chck.c
    reclaim.c
    stubborn.c
    typd_mlc.c
    gc++.cc    -- this is 'gc_cpp.cc' with less 'inline' and
               -- throw std::bad_alloc when out of memory
               -- gc_cpp.cc works just fine too

2) Test that the library works with 'test.c'.
=============================================

The test app is just an ordinary ANSI-C console app. Make sure settings
match the library you're testing.

Files
-----
    test.c
    the GC library to test        -- link order before ANSI libs
    suitable Mac+ANSI libraries

prefix:
------
---- ( cut here ) ----  gc_prefix_testlib.h     -- all libs -----
#define MSL_USE_PRECOMPILED_HEADERS 0
#include <ansi_prefix.mac.h>
#undef NDEBUG

#define ALL_INTERIOR_POINTERS	/* for GC_priv.h */
---- ( cut here ) ----

3) Test that the C++ interface 'gc_cpp.cc/h' works with 'test_cpp.cc'.

The test app is just an ordinary ANSI-C console app. Make sure settings match
the library you're testing.

Files
-----
    test_cpp.cc
    the GC library to test        -- link order before ANSI libs
    suitable Mac+ANSI libraries

prefix:
------
same as for test.c

For convenience I used one test-project with several targets so that all
test apps are build at once. Two for each library to test: test.c and
gc_app.cc. When I was satisfied that the libraries were ok. I put the
libraries + gc.h + the c++ interface-file in a folder that I then put into
the MSL hierarchy so that I don't have to alter access-paths in projects
that use the GC.

After that, just add the proper GC library to your project and the GC is in
action! malloc will call GC_malloc and free GC_free, new/delete too. You
don't have to call free or delete. You may have to be a bit cautious about
delete if you're freeing other resources than RAM. See gc_cpp.h. You can
also keep coding as always with delete/free. That works too. If you want,
"include <gc.h> and tweak it's use a bit.

Symantec SPM
============
It has been a while since I tried the GC in SPM, but I think that the above
instructions should be sufficient to guide you through in SPM too. SPM
needs to know where the global data is. Use the files 'datastart.c' and
'dataend.c'. Put 'datastart.c' at the top of your project and 'dataend.c'
at the bottom  of your project so that all data is surrounded. This is not
needed in Codewarrior because it provides intrinsic variables
__datastart__, __data_end__ that wraps all globals.

Source Changes (GC 4.12a2)
==========================
Very few. Just one tiny in the GC, not strictly needed.
- MacOS.c line 131 in routine GC_MacFreeTemporaryMemory()
  change #       if !defined(SHARED_LIBRARY_BUILD)
  to     #       if !defined(SILENT) && !defined(SHARED_LIBRARY_BUILD)
  To turn off a message when the application quits (actually, I faked
  this change by #defining SHARED_LIBRARY_BUILD in a statically linked
  library for more than a year without ill effects but perhaps this is
  better).

- test_cpp.cc
  made the first lines of main() look like this:
  ------------
  int main( int argc, char* argv[] ) {
  #endif
  #if macintosh                             // MacOS
    char* argv_[] = {"test_cpp","10"};      //   doesn't
    argv=argv_;                             //     have a
    argc = sizeof(argv_)/sizeof(argv_[0]);  //       commandline
  #endif                                    //

  int i, iters, n;
  # ifndef __GNUC__
   alloc dummy_to_fool_the_compiler_into_doing_things_it_currently_cant_handle;
  ------------

- config.h [now gcconfig.h]
  __MWERKS__ does not have to mean MACOS. You can use Codewarrior to
  build a Win32 or BeOS library and soon a Rhapsody library. You may
  have to change that #if...



   It worked for me, hope it works for you.

   Lars Farm
   18 July 1997
----------------------------------------------------------------------------


Patrick Beard's instructions (may be dated):

v4.3 of the collector now runs under Symantec C++/THINK C v7.0.4, and
Metrowerks C/C++ v4.5 both 68K and PowerPC. Project files are provided
to build and test the collector under both development systems.

Configuration
-------------

To configure the collector, under both development systems, a prefix file
is used to set preprocessor directives. This file is called "MacOS_config.h".
Also to test the collector, "MacOS_Test_config.h" is provided.

Testing
-------

To test the collector (always a good idea), build one of the gctest projects,
gctest.¹ (Symantec C++/THINK C), mw/gctest.68K.¹, or mw/gctest.PPC.¹. The
test will ask you how many times to run; 1 should be sufficient.

Building 
--------

For your convenience project files for the major Macintosh development
systems are provided.

For Symantec C++/THINK C, you must build the two projects gclib-1.¹ and
gclib-2.¹. It has to be split up because the collector has more than 32k
of static data and no library can have more than this in the Symantec
environment. (Future versions will probably fix this.)

For Metrowerks C/C++ 4.5 you build gc.68K.¹/gc.PPC.¹ and the result will
be a library called gc.68K.lib/gc.PPC.lib.

Using
-----

Under Symantec C++/THINK C, you can just add the gclib-1.¹ and gclib-2.¹
projects to your own project. Under Metrowerks, you add gc.68K.lib or
gc.PPC.lib and two additional files. You add the files called datastart.c
and dataend.c to your project, bracketing all files that use the collector.
See mw/gctest.¹ for an example.

Include the projects/libraries you built above into your own project,
#include "gc.h", and call GC_malloc. You don't have to call GC_free.


Patrick C. Beard
January 4, 1995