Status ====== libffi-3.0.4 was released on February 24, 2008. Check the libffi web page for updates: . 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 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, although this release was only tested on: arm oabi linux arm eabi linux hppa linux mips o32 linux (little endian) powerpc darwin powerpc64 linux sparc solaris sparc64 solaris x86 cygwin x86 darwin x86 freebsd x86 linux x86 openbsd x86-64 darwin x86-64 linux x86-64 OS X x86-64 freebsd Please send additional platform test results to libffi-discuss@sourceware.org. Installing libffi ================= [Note: before actually performing any of these installation steps, you may wish to read the "Platform Specific Notes" below.] 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. 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". Platform Specific Notes ======================= MIPS - Irix 5.3 & 6.x --------------------- Irix 6.2 and better supports three different calling conventions: o32, n32 and n64. Currently, libffi only supports both o32 and n32 under Irix 6.x, but only o32 under Irix 5.3. Libffi will automatically be configured for whichever calling convention it was built for. By default, the configure script will try to build libffi with the GNU development tools. To build libffi with the SGI development tools, set the environment variable CC to either "cc -32" or "cc -n32" before running configure under Irix 6.x (depending on whether you want an o32 or n32 library), or just "cc" for Irix 5.3. With the n32 calling convention, when returning structures smaller than 16 bytes, be sure to provide an RVALUE that is 8 byte aligned. Here's one way of forcing this: double struct_storage[2]; my_small_struct *s = (my_small_struct *) struct_storage; /* Use s for RVALUE */ If you don't do this you are liable to get spurious bus errors. "long long" values are not supported yet. You must use GNU Make to build libffi on SGI platforms. PowerPC System V ABI -------------------- There are two `System V ABI's which libffi implements for PowerPC. They differ only in how small structures are returned from functions. In the FFI_SYSV version, structures that are 8 bytes or smaller are returned in registers. This is what GCC does when it is configured for solaris, and is what the System V ABI I have (dated September 1995) says. In the FFI_GCC_SYSV version, all structures are returned the same way: by passing a pointer as the first argument to the function. This is what GCC does when it is configured for linux or a generic sysv target. EGCS 1.0.1 (and probably other versions of EGCS/GCC) also has a inconsistency with the SysV ABI: When a procedure is called with many floating-point arguments, some of them get put on the stack. They are all supposed to be stored in double-precision format, even if they are only single-precision, but EGCS stores single-precision arguments as single-precision anyway. This causes one test to fail (the `many arguments' test). History ======= 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 . 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 . 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: alpha Richard Henderson arm Raffaele Sena 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 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 green@redhat.com.