2013-04-10 Richard Biener <rguenther@suse.de>

[official-gcc.git] / libffi / README

Status
======

libffi-3.0.12 was released on XXXXXXX.  Check the libffi web page for
updates: <URL:http://sourceware.org/libffi/>.


What is libffi?
===============

Compilers for high level languages generate code that follow certain
conventions. These conventions are necessary, in part, for separate
compilation to work. One such convention is the "calling
convention". The "calling convention" is essentially a set of
assumptions made by the compiler about where function arguments will
be found on entry to a function. A "calling convention" also specifies
where the return value for a function is found.

Some programs may not know at the time of compilation what arguments
are to be passed to a function. For instance, an interpreter may be
told at run-time about the number and types of arguments used to call
a given function. Libffi can be used in such programs to provide a
bridge from the interpreter program to compiled code.

The libffi library provides a portable, high level programming
interface to various calling conventions. This allows a programmer to
call any function specified by a call interface description at run
time.  

FFI stands for Foreign Function Interface.  A foreign function
interface is the popular name for the interface that allows code
written in one language to call code written in another language. The
libffi library really only provides the lowest, machine dependent
layer of a fully featured foreign function interface. A layer must
exist above libffi that handles type conversions for values passed
between the two languages.


Supported Platforms
===================

Libffi has been ported to many different platforms.
For specific configuration details and testing status, please
refer to the wiki page here:

 http://www.moxielogic.org/wiki/index.php?title=Libffi_3.0.11

At the time of release, the following basic configurations have been
tested:

|-----------------+------------------|
| Architecture    | Operating System |
|-----------------+------------------|
| AArch64         | Linux            |
| Alpha           | Linux            |
| Alpha           | Tru64            |
| ARM             | Linux            |
| ARM             | iOS              |
| AVR32           | Linux            |
| Blackfin        | uClinux          |
| HPPA            | HPUX             |
| IA-64           | Linux            |
| M68K            | FreeMiNT         |
| M68K            | RTEMS            |
| MIPS            | IRIX             |
| MIPS            | Linux            |
| MIPS            | RTEMS            |
| MIPS64          | Linux            |
| PowerPC         | AMIGA            |
| PowerPC         | Linux            |
| PowerPC         | Mac OSX          |
| PowerPC         | FreeBSD          |
| PowerPC64       | Linux            |
| S390            | Linux            |
| S390X           | Linux            |
| SPARC           | Linux            |
| SPARC           | Solaris          |
| SPARC64         | Linux            |
| SPARC64         | FreeBSD          |
| TILE-Gx/TILEPro | Linux            |
| X86             | FreeBSD          |
| X86             | Interix          |
| X86             | kFreeBSD         |
| X86             | Linux            |
| X86             | Mac OSX          |
| X86             | OpenBSD          |
| X86             | OS/2             |
| X86             | Solaris          |
| X86             | Windows/Cygwin   |
| X86             | Windows/MingW    |
| X86-64          | FreeBSD          |
| X86-64          | Linux            |
| X86-64          | Linux/x32        |
| X86-64          | OpenBSD          |
| X86-64          | Windows/MingW    |
|-----------------+------------------|

Please send additional platform test results to
libffi-discuss@sourceware.org and feel free to update the wiki page
above.

Installing libffi
=================

First you must configure the distribution for your particular
system. Go to the directory you wish to build libffi in and run the
"configure" program found in the root directory of the libffi source
distribution.

You may want to tell configure where to install the libffi library and
header files. To do that, use the --prefix configure switch.  Libffi
will install under /usr/local by default. 

If you want to enable extra run-time debugging checks use the the
--enable-debug configure switch. This is useful when your program dies
mysteriously while using libffi. 

Another useful configure switch is --enable-purify-safety. Using this
will add some extra code which will suppress certain warnings when you
are using Purify with libffi. Only use this switch when using 
Purify, as it will slow down the library.

It's also possible to build libffi on Windows platforms with
Microsoft's Visual C++ compiler.  In this case, use the msvcc.sh
wrapper script during configuration like so:

path/to/configure CC=path/to/msvcc.sh LD=link CPP=\"cl -nologo -EP\"

For 64-bit Windows builds, use CC="path/to/msvcc.sh -m64".
You may also need to specify --build appropriately. When building with MSVC
under a MingW environment, you may need to remove the line in configure
that sets 'fix_srcfile_path' to a 'cygpath' command. ('cygpath' is not
present in MingW, and is not required when using MingW-style paths.)

For iOS builds, the 'libffi.xcodeproj' Xcode project is available.

Configure has many other options. Use "configure --help" to see them all.

Once configure has finished, type "make". Note that you must be using
GNU make.  You can ftp GNU make from prep.ai.mit.edu:/pub/gnu.

To ensure that libffi is working as advertised, type "make check".
This will require that you have DejaGNU installed.

To install the library and header files, type "make install".


History
=======

See the ChangeLog files for details.

3.0.12 XXX-XX-XX
        Add Blackfin support.
        Add TILE-Gx/TILEPro support.
        Add AArch64 support.
        Add support for PaX enabled kernels with MPROTECT.

3.0.11 Apr-11-12
        Lots of build fixes.
        Add Amiga newer MacOS support.
        Add support for variadic functions (ffi_prep_cif_var).
        Add Linux/x32 support.
        Add thiscall, fastcall and MSVC cdecl support on Windows.
        Add Amiga and newer MacOS support.
        Add m68k FreeMiNT support.
        Integration with iOS' xcode build tools.
        Fix Octeon and MC68881 support.
        Fix code pessimizations.
        Lots of build fixes.

3.0.10 Aug-23-11
        Add support for Apple's iOS.
        Add support for ARM VFP ABI.
        Add RTEMS support for MIPS and M68K.
        Fix instruction cache clearing problems on
          ARM and SPARC.
        Fix the N64 build on mips-sgi-irix6.5.
        Enable builds with Microsoft's compiler.
        Enable x86 builds with Oracle's Solaris compiler.
        Fix support for calling code compiled with Oracle's Sparc
          Solaris compiler.
        Testsuite fixes for Tru64 Unix.
        Additional platform support.

3.0.9 Dec-31-09
        Add AVR32 and win64 ports.  Add ARM softfp support.
        Many fixes for AIX, Solaris, HP-UX, *BSD.
        Several PowerPC and x86-64 bug fixes.
        Build DLL for windows.

3.0.8 Dec-19-08
        Add *BSD, BeOS, and PA-Linux support.

3.0.7 Nov-11-08
        Fix for ppc FreeBSD.
        (thanks to Andreas Tobler)

3.0.6 Jul-17-08
        Fix for closures on sh.
        Mark the sh/sh64 stack as non-executable.
        (both thanks to Kaz Kojima)

3.0.5 Apr-3-08
        Fix libffi.pc file.
        Fix #define ARM for IcedTea users.
        Fix x86 closure bug.

3.0.4 Feb-24-08
        Fix x86 OpenBSD configury.

3.0.3 Feb-22-08
        Enable x86 OpenBSD thanks to Thomas Heller, and
        x86-64 FreeBSD thanks to Björn König and Andreas Tobler.
        Clean up test instruction in README.

3.0.2 Feb-21-08
        Improved x86 FreeBSD support.
        Thanks to Björn König.

3.0.1 Feb-15-08
        Fix instruction cache flushing bug on MIPS.
        Thanks to David Daney.

3.0.0 Feb-15-08
        Many changes, mostly thanks to the GCC project.
        Cygnus Solutions is now Red Hat.

  [10 years go by...]

1.20 Oct-5-98
        Raffaele Sena produces ARM port.

1.19 Oct-5-98
        Fixed x86 long double and long long return support.
        m68k bug fixes from Andreas Schwab.
        Patch for DU assembler compatibility for the Alpha from Richard
        Henderson.

1.18 Apr-17-98
        Bug fixes and MIPS configuration changes.

1.17 Feb-24-98
        Bug fixes and m68k port from Andreas Schwab. PowerPC port from
        Geoffrey Keating. Various bug x86, Sparc and MIPS bug fixes.

1.16 Feb-11-98
        Richard Henderson produces Alpha port.

1.15 Dec-4-97
        Fixed an n32 ABI bug. New libtool, auto* support.

1.14 May-13-97
        libtool is now used to generate shared and static libraries.
        Fixed a minor portability problem reported by Russ McManus
        <mcmanr@eq.gs.com>.

1.13 Dec-2-96
        Added --enable-purify-safety to keep Purify from complaining
        about certain low level code.
        Sparc fix for calling functions with < 6 args.
        Linux x86 a.out fix.

1.12 Nov-22-96
        Added missing ffi_type_void, needed for supporting void return 
        types. Fixed test case for non MIPS machines. Cygnus Support 
        is now Cygnus Solutions. 

1.11 Oct-30-96
        Added notes about GNU make.

1.10 Oct-29-96
        Added configuration fix for non GNU compilers.

1.09 Oct-29-96
        Added --enable-debug configure switch. Clean-ups based on LCLint 
        feedback. ffi_mips.h is always installed. Many configuration 
        fixes. Fixed ffitest.c for sparc builds.

1.08 Oct-15-96
        Fixed n32 problem. Many clean-ups.

1.07 Oct-14-96
        Gordon Irlam rewrites v8.S again. Bug fixes.

1.06 Oct-14-96
        Gordon Irlam improved the sparc port. 

1.05 Oct-14-96
        Interface changes based on feedback.

1.04 Oct-11-96
        Sparc port complete (modulo struct passing bug).

1.03 Oct-10-96
        Passing struct args, and returning struct values works for
        all architectures/calling conventions. Expanded tests.

1.02 Oct-9-96
        Added SGI n32 support. Fixed bugs in both o32 and Linux support.
        Added "make test".

1.01 Oct-8-96
        Fixed float passing bug in mips version. Restructured some
        of the code. Builds cleanly with SGI tools.

1.00 Oct-7-96
        First release. No public announcement.


Authors & Credits
=================

libffi was originally written by Anthony Green <green@redhat.com>.

The developers of the GNU Compiler Collection project have made
innumerable valuable contributions.  See the ChangeLog file for
details.

Some of the ideas behind libffi were inspired by Gianni Mariani's free
gencall library for Silicon Graphics machines.

The closure mechanism was designed and implemented by Kresten Krab
Thorup.

Major processor architecture ports were contributed by the following
developers:

aarch64         Marcus Shawcroft, James Greenhalgh
alpha           Richard Henderson
arm             Raffaele Sena
blackfin        Alexandre Keunecke I. de Mendonca
cris            Simon Posnjak, Hans-Peter Nilsson
frv             Anthony Green
ia64            Hans Boehm
m32r            Kazuhiro Inaoka
m68k            Andreas Schwab
mips            Anthony Green, Casey Marshall
mips64          David Daney
pa              Randolph Chung, Dave Anglin, Andreas Tobler
powerpc         Geoffrey Keating, Andreas Tobler, 
                         David Edelsohn, John Hornkvist
powerpc64       Jakub Jelinek
s390            Gerhard Tonn, Ulrich Weigand
sh              Kaz Kojima
sh64            Kaz Kojima
sparc           Anthony Green, Gordon Irlam
tile-gx/tilepro Walter Lee
x86             Anthony Green, Jon Beniston
x86-64          Bo Thorsen

Jesper Skov and Andrew Haley both did more than their fair share of
stepping through the code and tracking down bugs.

Thanks also to Tom Tromey for bug fixes, documentation and
configuration help.

Thanks to Jim Blandy, who provided some useful feedback on the libffi
interface.

Andreas Tobler has done a tremendous amount of work on the testsuite.

Alex Oliva solved the executable page problem for SElinux.

The list above is almost certainly incomplete and inaccurate.  I'm
happy to make corrections or additions upon request.

If you have a problem, or have found a bug, please send a note to the
author at green@moxielogic.com, or the project mailing list at
libffi-discuss@sourceware.org.