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README: Import from libffi 3.0.8.

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2009-06-08  Andrew Haley  <aph@redhat.com>

	* README: Import from libffi 3.0.8.

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libffi/ChangeLog
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@ -1,3 +1,7 @@
2009-06-08 Andrew Haley <aph@redhat.com>
* README: Import from libffi 3.0.8.
2009-06-08 Andrew Haley <aph@redhat.com>
* testsuite/libffi.call/err_bad_abi.c: Add xfails.

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libffi/README
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@ -4,10 +4,8 @@ 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-3.0.8 was released on December 19, 2008. Check the libffi web
page for updates: <URL:http://sourceware.org/libffi/>.
What is libffi?
@ -32,7 +30,7 @@ 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
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
@ -41,38 +39,36 @@ exist above libffi that handles type conversions for values passed
between the two languages.
Supported Platforms and Prerequisites
=====================================
Supported Platforms
===================
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).
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
powerpc freebsd
powerpc64 linux
sparc solaris
sparc64 freebsd
sparc64 solaris
x86 cygwin
x86 darwin
x86 freebsd
x86 linux
x86 openbsd
x86 solaris
x86-64 darwin
x86-64 linux
x86-64 OS X
x86-64 freebsd
x86-64 solaris
Please send additional platform test results to
libffi-discuss@sourceware.org.
Installing libffi
=================
@ -101,216 +97,17 @@ 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. 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_pointer;
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
---------------------
@ -339,13 +136,6 @@ If you don't do this you are liable to get spurious bus errors.
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
--------------------
@ -375,6 +165,42 @@ arguments' test).
History
=======
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.
@ -458,34 +284,56 @@ History
Authors & Credits
=================
libffi was written by Anthony Green <green@cygnus.com>.
libffi was originally written by Anthony Green <green@redhat.com>.
Portions of libffi were derived from Gianni Mariani's free gencall
library for Silicon Graphics machines.
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.
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>.
Major processor architecture ports were contributed by the following
developers:
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.
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.