-This directory contains the libffi package, which is not part of GCC but
-shipped with GCC as convenience.
-
Status
======
-libffi-2.00 has not been released yet! This is a development snapshot!
-
-libffi-1.20 was released on October 5, 1998. Check the libffi web
-page for updates: <URL:http://sources.redhat.com/libffi/>.
+libffi-3.0.6 was released on July 17, 2008. 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.
+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
+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
+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
+interface to various calling conventions. This allows a programmer to
call any function specified by a call interface description at run
-time.
+time.
-Ffi stands for Foreign Function Interface. A foreign function
+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
+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 and Prerequisites
-=====================================
-
-Libffi has been ported to:
-
- SunOS 4.1.3 & Solaris 2.x (SPARC-V8, SPARC-V9)
-
- Irix 5.3 & 6.2 (System V/o32 & n32)
-
- Intel x86 - Linux (System V ABI)
-
- Alpha - Linux and OSF/1
-
- m68k - Linux (System V ABI)
-
- PowerPC - Linux (System V ABI, Darwin, AIX)
-
- ARM - Linux (System V ABI)
-
-Libffi has been tested with the egcs 1.0.2 gcc compiler. Chances are
-that other versions will work. Libffi has also been built and tested
-with the SGI compiler tools.
-
-On PowerPC, the tests failed (see the note below).
-
-You must use GNU make to build libffi. SGI's make will not work.
-Sun's probably won't either.
-
-If you port libffi to another platform, please let me know! I assume
-that some will be easy (x86 NetBSD), and others will be more difficult
-(HP).
-
+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
=================
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. SGI's make will not work. Sun's probably won't either.
-You can ftp GNU make from prep.ai.mit.edu:/pub/gnu.
+GNU make. You can ftp GNU make from prep.ai.mit.edu:/pub/gnu.
-To ensure that libffi is working as advertised, type "make test".
+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".
-Using libffi
-============
-
- The Basics
- ----------
-
-Libffi assumes that you have a pointer to the function you wish to
-call and that you know the number and types of arguments to pass it,
-as well as the return type of the function.
-
-The first thing you must do is create an ffi_cif object that matches
-the signature of the function you wish to call. The cif in ffi_cif
-stands for Call InterFace. To prepare a call interface object, use the
-following function:
-
-ffi_status ffi_prep_cif(ffi_cif *cif, ffi_abi abi,
- unsigned int nargs,
- ffi_type *rtype, ffi_type **atypes);
-
- CIF is a pointer to the call interface object you wish
- to initialize.
-
- ABI is an enum that specifies the calling convention
- to use for the call. FFI_DEFAULT_ABI defaults
- to the system's native calling convention. Other
- ABI's may be used with care. They are system
- specific.
-
- NARGS is the number of arguments this function accepts.
- libffi does not yet support vararg functions.
-
- RTYPE is a pointer to an ffi_type structure that represents
- the return type of the function. Ffi_type objects
- describe the types of values. libffi provides
- ffi_type objects for many of the native C types:
- signed int, unsigned int, signed char, unsigned char,
- etc. There is also a pointer ffi_type object and
- a void ffi_type. Use &ffi_type_void for functions that
- don't return values.
-
- ATYPES is a vector of ffi_type pointers. ARGS must be NARGS long.
- If NARGS is 0, this is ignored.
-
-
-ffi_prep_cif will return a status code that you are responsible
-for checking. It will be one of the following:
-
- FFI_OK - All is good.
-
- FFI_BAD_TYPEDEF - One of the ffi_type objects that ffi_prep_cif
- came across is bad.
-
-
-Before making the call, the VALUES vector should be initialized
-with pointers to the appropriate argument values.
-
-To call the the function using the initialized ffi_cif, use the
-ffi_call function:
-
-void ffi_call(ffi_cif *cif, void *fn, void *rvalue, void **avalues);
-
- CIF is a pointer to the ffi_cif initialized specifically
- for this function.
-
- FN is a pointer to the function you want to call.
-
- RVALUE is a pointer to a chunk of memory that is to hold the
- result of the function call. Currently, it must be
- at least one word in size (except for the n32 version
- under Irix 6.x, which must be a pointer to an 8 byte
- aligned value (a long long). It must also be at least
- word aligned (depending on the return type, and the
- system's alignment requirements). If RTYPE is
- &ffi_type_void, this is ignored. If RVALUE is NULL,
- the return value is discarded.
-
- AVALUES is a vector of void* that point to the memory locations
- holding the argument values for a call.
- If NARGS is 0, this is ignored.
-
-
-If you are expecting a return value from FN it will have been stored
-at RVALUE.
-
-
-
- An Example
- ----------
-
-Here is a trivial example that calls puts() a few times.
-
- #include <stdio.h>
- #include <ffi.h>
-
- int main()
- {
- ffi_cif cif;
- ffi_type *args[1];
- void *values[1];
- char *s;
- int rc;
-
- /* Initialize the argument info vectors */
- args[0] = &ffi_type_uint;
- values[0] = &s;
-
- /* Initialize the cif */
- if (ffi_prep_cif(&cif, FFI_DEFAULT_ABI, 1,
- &ffi_type_uint, args) == FFI_OK)
- {
- s = "Hello World!";
- ffi_call(&cif, puts, &rc, values);
- /* rc now holds the result of the call to puts */
-
- /* values holds a pointer to the function's arg, so to
- call puts() again all we need to do is change the
- value of s */
- s = "This is cool!";
- ffi_call(&cif, puts, &rc, values);
- }
-
- return 0;
- }
-
-
-
- Aggregate Types
- ---------------
-
-Although libffi has no special support for unions or bit-fields, it is
-perfectly happy passing structures back and forth. You must first
-describe the structure to libffi by creating a new ffi_type object
-for it. Here is the definition of ffi_type:
-
- typedef struct _ffi_type
- {
- unsigned size;
- short alignment;
- short type;
- struct _ffi_type **elements;
- } ffi_type;
-
-All structures must have type set to FFI_TYPE_STRUCT. You may set
-size and alignment to 0. These will be calculated and reset to the
-appropriate values by ffi_prep_cif().
-
-elements is a NULL terminated array of pointers to ffi_type objects
-that describe the type of the structure elements. These may, in turn,
-be structure elements.
-
-The following example initializes a ffi_type object representing the
-tm struct from Linux's time.h:
-
- struct tm {
- int tm_sec;
- int tm_min;
- int tm_hour;
- int tm_mday;
- int tm_mon;
- int tm_year;
- int tm_wday;
- int tm_yday;
- int tm_isdst;
- /* Those are for future use. */
- long int __tm_gmtoff__;
- __const char *__tm_zone__;
- };
-
- {
- ffi_type tm_type;
- ffi_type *tm_type_elements[12];
- int i;
-
- tm_type.size = tm_type.alignment = 0;
- tm_type.elements = &tm_type_elements;
-
- for (i = 0; i < 9; i++)
- tm_type_elements[i] = &ffi_type_sint;
-
- tm_type_elements[9] = &ffi_type_slong;
- tm_type_elements[10] = &ffi_type_pointer;
- tm_type_elements[11] = NULL;
-
- /* tm_type can now be used to represent tm argument types and
- return types for ffi_prep_cif() */
- }
-
-
-
Platform Specific Notes
=======================
- Intel x86
- ---------
-
-There are no known problems with the x86 port.
-
- Sun SPARC - SunOS 4.1.3 & Solaris 2.x
- -------------------------------------
-
-You must use GNU Make to build libffi on Sun platforms.
-
MIPS - Irix 5.3 & 6.x
---------------------
You must use GNU Make to build libffi on SGI platforms.
- ARM - System V ABI
- ------------------
-
-The ARM port was performed on a NetWinder running ARM Linux ELF
-(2.0.31) and gcc 2.8.1.
-
-
PowerPC System V ABI
--------------------
History
=======
+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.
Authors & Credits
=================
-libffi was written by Anthony Green <green@cygnus.com>.
+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.
-Portions of libffi were derived from Gianni Mariani's free gencall
-library for Silicon Graphics machines.
+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.
-The Sparc port was derived from code contributed by the fine folks at
-Visible Decisions Inc <http://www.vdi.com>. Further enhancements were
-made by Gordon Irlam at Cygnus Solutions <http://www.cygnus.com>.
-
-The Alpha port was written by Richard Henderson at Cygnus Solutions.
-
-Andreas Schwab ported libffi to m68k Linux and provided a number of
-bug fixes.
-
-Geoffrey Keating ported libffi to the PowerPC.
-
-Raffaele Sena ported libffi to the ARM.
+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 and configuration help.
+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@cygnus.com.
+green@redhat.com.
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