README.md

Status

libffi-3.3-rc0 was released on April 2, 2018. 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.

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

Architecture Operating System Compiler AArch64 (ARM64) iOS Clang AArch64 Linux GCC Alpha Linux GCC Alpha Tru64 GCC ARC Linux GCC ARM Linux GCC ARM iOS GCC AVR32 Linux GCC Blackfin uClinux GCC HPPA HPUX GCC IA-64 Linux GCC M68K FreeMiNT GCC M68K Linux GCC M68K RTEMS GCC M88K OpenBSD/mvme88k GCC Meta Linux GCC MicroBlaze Linux GCC MIPS IRIX GCC MIPS Linux GCC MIPS RTEMS GCC MIPS64 Linux GCC Moxie Bare metal GCC Nios II Linux GCC OpenRISC Linux GCC PowerPC 32-bit AIX IBM XL C PowerPC 64-bit AIX IBM XL C PowerPC AMIGA GCC PowerPC Linux GCC PowerPC Mac OSX GCC PowerPC FreeBSD GCC PowerPC 64-bit FreeBSD GCC PowerPC 64-bit Linux ELFv1 GCC PowerPC 64-bit Linux ELFv2 GCC RISC-V 32-bit Linux GCC RISC-V 64-bit Linux GCC S390 Linux GCC S390X Linux GCC SPARC Linux GCC SPARC Solaris GCC SPARC Solaris Oracle Solaris Studio C SPARC64 Linux GCC SPARC64 FreeBSD GCC SPARC64 Solaris Oracle Solaris Studio C TILE-Gx/TILEPro Linux GCC VAX OpenBSD/vax GCC X86 FreeBSD GCC X86 GNU HURD GCC X86 Interix GCC X86 kFreeBSD GCC X86 Linux GCC X86 Mac OSX GCC X86 OpenBSD GCC X86 OS/2 GCC X86 Solaris GCC X86 Solaris Oracle Solaris Studio C X86 Windows/Cygwin GCC X86 Windows/MingW GCC X86-64 FreeBSD GCC X86-64 Linux GCC X86-64 Linux/x32 GCC X86-64 OpenBSD GCC X86-64 Solaris Oracle Solaris Studio C X86-64 Windows/Cygwin GCC X86-64 Windows/MingW GCC X86-64 Mac OSX GCC Xtensa Linux GCC

Please send additional platform test results to [email protected].

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. Note that building libffi requires a C99 compatible compiler.

If you're building libffi directly from git hosted sources, configure won't exist yet; run ./autogen.sh first. This will require that you install autoconf, automake and libtool.

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.

If you don't want to build documentation, use the --disable-docs configure switch.

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 CXX=path/to/msvcc.sh LD=link CPP="cl -nologo -EP"

For 64-bit Windows builds, use CC="path/to/msvcc.sh -m64" and CXX="path/to/msvcc.sh -m64". You may also need to specify --build appropriately.

It is also possible to build libffi on Windows platforms with the LLVM project's clang-cl compiler, like below:

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

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.)

SPARC Solaris builds require the use of the GNU assembler and linker. Point AS and LD environment variables at those tool prior to configuration.

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 ftp.gnu.org:/pub/gnu/make .

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 git log for details at http://github.com/libffi/libffi.

3.3 TBD
    Add RISC-V support.
    New API in support of GO closures.
    Default to Microsoft's 64 bit long double ABI with Visual C++.
      GNU compiler uses 80 bits (128 in memory) FFI_GNUW64 ABI.
Many new tests cases and bug fixes.

3.2.1 Nov-12-14
    Build fix for non-iOS AArch64 targets.

3.2 Nov-11-14
    Add C99 Complex Type support (currently only supported on
      s390).
    Add support for PASCAL and REGISTER calling conventions on x86
      Windows/Linux.
    Add OpenRISC and Cygwin-64 support.
    Bug fixes.

3.1 May-19-14
    Add AArch64 (ARM64) iOS support.
    Add Nios II support.
    Add m88k and DEC VAX support.
    Add support for stdcall, thiscall, and fastcall on non-Windows
      32-bit x86 targets such as Linux.
    Various Android, MIPS N32, x86, FreeBSD and UltraSPARC IIi
      fixes.
    Make the testsuite more robust: eliminate several spurious
      failures, and respect the $CC and $CXX environment variables.
    Archive off the manually maintained ChangeLog in favor of git
      log.

3.0.13 Mar-17-13
    Add Meta support.
    Add missing Moxie bits.
    Fix stack alignment bug on 32-bit x86.
    Build fix for m68000 targets.
    Build fix for soft-float Power targets.
    Fix the install dir location for some platforms when building
      with GCC (OS X, Solaris).
    Fix Cygwin regression.

3.0.12 Feb-11-13
    Add Moxie support.
    Add AArch64 support.
    Add Blackfin support.
    Add TILE-Gx/TILEPro support.
    Add MicroBlaze support.
    Add Xtensa support.
    Add support for PaX enabled kernels with MPROTECT.
    Add support for native vendor compilers on
      Solaris and AIX.
    Work around LLVM/GCC interoperability issue on x86_64.

3.0.11 Apr-11-12
    Lots of build fixes.
    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.

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
    <[email protected]>.

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 [email protected].

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
m88k                Miod Vallat
microblaze          Nathan Rossi
mips                Anthony Green, Casey Marshall
mips64              David Daney
moxie               Anthony Green
nios ii             Sandra Loosemore
openrisc            Sebastian Macke
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
vax                 Miod Vallat
x86                 Anthony Green, Jon Beniston
x86-64              Bo Thorsen
xtensa              Chris Zankel

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 [email protected], or the project mailing list at [email protected].