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1 | This directory contains the libffi package, which is not part of GCC but |
2 | shipped with GCC as convenience. | |
3 | ||
4 | Status | |
5 | ====== | |
63e5e3e0 | 6 | |
491e6ad1 AH |
7 | libffi-3.0.8 was released on December 19, 2008. Check the libffi web |
8 | page for updates: <URL:http://sourceware.org/libffi/>. | |
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9 | |
10 | ||
11 | What is libffi? | |
12 | =============== | |
13 | ||
14 | Compilers for high level languages generate code that follow certain | |
15 | conventions. These conventions are necessary, in part, for separate | |
16 | compilation to work. One such convention is the "calling | |
17 | convention". The "calling convention" is essentially a set of | |
18 | assumptions made by the compiler about where function arguments will | |
19 | be found on entry to a function. A "calling convention" also specifies | |
20 | where the return value for a function is found. | |
21 | ||
22 | Some programs may not know at the time of compilation what arguments | |
23 | are to be passed to a function. For instance, an interpreter may be | |
24 | told at run-time about the number and types of arguments used to call | |
25 | a given function. Libffi can be used in such programs to provide a | |
26 | bridge from the interpreter program to compiled code. | |
27 | ||
28 | The libffi library provides a portable, high level programming | |
29 | interface to various calling conventions. This allows a programmer to | |
30 | call any function specified by a call interface description at run | |
31 | time. | |
32 | ||
491e6ad1 | 33 | FFI stands for Foreign Function Interface. A foreign function |
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34 | interface is the popular name for the interface that allows code |
35 | written in one language to call code written in another language. The | |
36 | libffi library really only provides the lowest, machine dependent | |
37 | layer of a fully featured foreign function interface. A layer must | |
38 | exist above libffi that handles type conversions for values passed | |
39 | between the two languages. | |
40 | ||
41 | ||
491e6ad1 AH |
42 | Supported Platforms |
43 | =================== | |
44 | ||
45 | Libffi has been ported to many different platforms, although this | |
46 | release was only tested on: | |
47 | ||
48 | arm oabi linux | |
49 | arm eabi linux | |
50 | hppa linux | |
51 | mips o32 linux (little endian) | |
52 | powerpc darwin | |
53 | powerpc freebsd | |
54 | powerpc64 linux | |
55 | sparc solaris | |
56 | sparc64 freebsd | |
57 | sparc64 solaris | |
58 | x86 cygwin | |
59 | x86 darwin | |
60 | x86 freebsd | |
61 | x86 linux | |
62 | x86 openbsd | |
63 | x86 solaris | |
64 | x86-64 darwin | |
65 | x86-64 linux | |
66 | x86-64 OS X | |
67 | x86-64 freebsd | |
68 | x86-64 solaris | |
69 | ||
70 | Please send additional platform test results to | |
71 | libffi-discuss@sourceware.org. | |
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72 | |
73 | Installing libffi | |
74 | ================= | |
75 | ||
76 | [Note: before actually performing any of these installation steps, | |
77 | you may wish to read the "Platform Specific Notes" below.] | |
78 | ||
79 | First you must configure the distribution for your particular | |
80 | system. Go to the directory you wish to build libffi in and run the | |
81 | "configure" program found in the root directory of the libffi source | |
82 | distribution. | |
83 | ||
84 | You may want to tell configure where to install the libffi library and | |
85 | header files. To do that, use the --prefix configure switch. Libffi | |
86 | will install under /usr/local by default. | |
87 | ||
88 | If you want to enable extra run-time debugging checks use the the | |
89 | --enable-debug configure switch. This is useful when your program dies | |
90 | mysteriously while using libffi. | |
91 | ||
92 | Another useful configure switch is --enable-purify-safety. Using this | |
93 | will add some extra code which will suppress certain warnings when you | |
94 | are using Purify with libffi. Only use this switch when using | |
95 | Purify, as it will slow down the library. | |
96 | ||
97 | Configure has many other options. Use "configure --help" to see them all. | |
98 | ||
99 | Once configure has finished, type "make". Note that you must be using | |
491e6ad1 | 100 | GNU make. You can ftp GNU make from prep.ai.mit.edu:/pub/gnu. |
63e5e3e0 | 101 | |
491e6ad1 AH |
102 | To ensure that libffi is working as advertised, type "make check". |
103 | This will require that you have DejaGNU installed. | |
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104 | |
105 | To install the library and header files, type "make install". | |
106 | ||
107 | ||
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108 | Platform Specific Notes |
109 | ======================= | |
110 | ||
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111 | MIPS - Irix 5.3 & 6.x |
112 | --------------------- | |
113 | ||
114 | Irix 6.2 and better supports three different calling conventions: o32, | |
115 | n32 and n64. Currently, libffi only supports both o32 and n32 under | |
116 | Irix 6.x, but only o32 under Irix 5.3. Libffi will automatically be | |
117 | configured for whichever calling convention it was built for. | |
118 | ||
119 | By default, the configure script will try to build libffi with the GNU | |
120 | development tools. To build libffi with the SGI development tools, set | |
121 | the environment variable CC to either "cc -32" or "cc -n32" before | |
122 | running configure under Irix 6.x (depending on whether you want an o32 | |
123 | or n32 library), or just "cc" for Irix 5.3. | |
124 | ||
125 | With the n32 calling convention, when returning structures smaller | |
126 | than 16 bytes, be sure to provide an RVALUE that is 8 byte aligned. | |
127 | Here's one way of forcing this: | |
128 | ||
129 | double struct_storage[2]; | |
130 | my_small_struct *s = (my_small_struct *) struct_storage; | |
131 | /* Use s for RVALUE */ | |
132 | ||
133 | If you don't do this you are liable to get spurious bus errors. | |
134 | ||
135 | "long long" values are not supported yet. | |
136 | ||
137 | You must use GNU Make to build libffi on SGI platforms. | |
138 | ||
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139 | |
140 | PowerPC System V ABI | |
141 | -------------------- | |
142 | ||
143 | There are two `System V ABI's which libffi implements for PowerPC. | |
144 | They differ only in how small structures are returned from functions. | |
145 | ||
146 | In the FFI_SYSV version, structures that are 8 bytes or smaller are | |
147 | returned in registers. This is what GCC does when it is configured | |
148 | for solaris, and is what the System V ABI I have (dated September | |
149 | 1995) says. | |
150 | ||
151 | In the FFI_GCC_SYSV version, all structures are returned the same way: | |
152 | by passing a pointer as the first argument to the function. This is | |
153 | what GCC does when it is configured for linux or a generic sysv | |
154 | target. | |
155 | ||
156 | EGCS 1.0.1 (and probably other versions of EGCS/GCC) also has a | |
157 | inconsistency with the SysV ABI: When a procedure is called with many | |
158 | floating-point arguments, some of them get put on the stack. They are | |
159 | all supposed to be stored in double-precision format, even if they are | |
160 | only single-precision, but EGCS stores single-precision arguments as | |
161 | single-precision anyway. This causes one test to fail (the `many | |
162 | arguments' test). | |
163 | ||
164 | ||
63e5e3e0 AG |
165 | History |
166 | ======= | |
167 | ||
491e6ad1 AH |
168 | 3.0.7 Nov-11-08 |
169 | Fix for ppc FreeBSD. | |
170 | (thanks to Andreas Tobler) | |
171 | ||
172 | 3.0.6 Jul-17-08 | |
173 | Fix for closures on sh. | |
174 | Mark the sh/sh64 stack as non-executable. | |
175 | (both thanks to Kaz Kojima) | |
176 | ||
177 | 3.0.5 Apr-3-08 | |
178 | Fix libffi.pc file. | |
179 | Fix #define ARM for IcedTea users. | |
180 | Fix x86 closure bug. | |
181 | ||
182 | 3.0.4 Feb-24-08 | |
183 | Fix x86 OpenBSD configury. | |
184 | ||
185 | 3.0.3 Feb-22-08 | |
186 | Enable x86 OpenBSD thanks to Thomas Heller, and | |
187 | x86-64 FreeBSD thanks to Björn König and Andreas Tobler. | |
188 | Clean up test instruction in README. | |
189 | ||
190 | 3.0.2 Feb-21-08 | |
191 | Improved x86 FreeBSD support. | |
192 | Thanks to Björn König. | |
193 | ||
194 | 3.0.1 Feb-15-08 | |
195 | Fix instruction cache flushing bug on MIPS. | |
196 | Thanks to David Daney. | |
197 | ||
198 | 3.0.0 Feb-15-08 | |
199 | Many changes, mostly thanks to the GCC project. | |
200 | Cygnus Solutions is now Red Hat. | |
201 | ||
202 | [10 years go by...] | |
203 | ||
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204 | 1.20 Oct-5-98 |
205 | Raffaele Sena produces ARM port. | |
206 | ||
207 | 1.19 Oct-5-98 | |
208 | Fixed x86 long double and long long return support. | |
209 | m68k bug fixes from Andreas Schwab. | |
210 | Patch for DU assembler compatibility for the Alpha from Richard | |
211 | Henderson. | |
212 | ||
213 | 1.18 Apr-17-98 | |
214 | Bug fixes and MIPS configuration changes. | |
215 | ||
216 | 1.17 Feb-24-98 | |
217 | Bug fixes and m68k port from Andreas Schwab. PowerPC port from | |
218 | Geoffrey Keating. Various bug x86, Sparc and MIPS bug fixes. | |
219 | ||
220 | 1.16 Feb-11-98 | |
221 | Richard Henderson produces Alpha port. | |
222 | ||
223 | 1.15 Dec-4-97 | |
224 | Fixed an n32 ABI bug. New libtool, auto* support. | |
225 | ||
226 | 1.14 May-13-97 | |
227 | libtool is now used to generate shared and static libraries. | |
228 | Fixed a minor portability problem reported by Russ McManus | |
229 | <mcmanr@eq.gs.com>. | |
230 | ||
231 | 1.13 Dec-2-96 | |
232 | Added --enable-purify-safety to keep Purify from complaining | |
233 | about certain low level code. | |
234 | Sparc fix for calling functions with < 6 args. | |
235 | Linux x86 a.out fix. | |
236 | ||
237 | 1.12 Nov-22-96 | |
238 | Added missing ffi_type_void, needed for supporting void return | |
239 | types. Fixed test case for non MIPS machines. Cygnus Support | |
240 | is now Cygnus Solutions. | |
241 | ||
242 | 1.11 Oct-30-96 | |
243 | Added notes about GNU make. | |
244 | ||
245 | 1.10 Oct-29-96 | |
246 | Added configuration fix for non GNU compilers. | |
247 | ||
248 | 1.09 Oct-29-96 | |
249 | Added --enable-debug configure switch. Clean-ups based on LCLint | |
250 | feedback. ffi_mips.h is always installed. Many configuration | |
251 | fixes. Fixed ffitest.c for sparc builds. | |
252 | ||
253 | 1.08 Oct-15-96 | |
254 | Fixed n32 problem. Many clean-ups. | |
255 | ||
256 | 1.07 Oct-14-96 | |
257 | Gordon Irlam rewrites v8.S again. Bug fixes. | |
258 | ||
259 | 1.06 Oct-14-96 | |
260 | Gordon Irlam improved the sparc port. | |
261 | ||
262 | 1.05 Oct-14-96 | |
263 | Interface changes based on feedback. | |
264 | ||
265 | 1.04 Oct-11-96 | |
266 | Sparc port complete (modulo struct passing bug). | |
267 | ||
268 | 1.03 Oct-10-96 | |
269 | Passing struct args, and returning struct values works for | |
270 | all architectures/calling conventions. Expanded tests. | |
271 | ||
272 | 1.02 Oct-9-96 | |
273 | Added SGI n32 support. Fixed bugs in both o32 and Linux support. | |
274 | Added "make test". | |
275 | ||
276 | 1.01 Oct-8-96 | |
277 | Fixed float passing bug in mips version. Restructured some | |
278 | of the code. Builds cleanly with SGI tools. | |
279 | ||
280 | 1.00 Oct-7-96 | |
281 | First release. No public announcement. | |
282 | ||
283 | ||
284 | Authors & Credits | |
285 | ================= | |
286 | ||
491e6ad1 AH |
287 | libffi was originally written by Anthony Green <green@redhat.com>. |
288 | ||
289 | The developers of the GNU Compiler Collection project have made | |
290 | innumerable valuable contributions. See the ChangeLog file for | |
291 | details. | |
63e5e3e0 | 292 | |
491e6ad1 AH |
293 | Some of the ideas behind libffi were inspired by Gianni Mariani's free |
294 | gencall library for Silicon Graphics machines. | |
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295 | |
296 | The closure mechanism was designed and implemented by Kresten Krab | |
297 | Thorup. | |
298 | ||
491e6ad1 AH |
299 | Major processor architecture ports were contributed by the following |
300 | developers: | |
301 | ||
302 | alpha Richard Henderson | |
303 | arm Raffaele Sena | |
304 | cris Simon Posnjak, Hans-Peter Nilsson | |
305 | frv Anthony Green | |
306 | ia64 Hans Boehm | |
307 | m32r Kazuhiro Inaoka | |
308 | m68k Andreas Schwab | |
309 | mips Anthony Green, Casey Marshall | |
310 | mips64 David Daney | |
311 | pa Randolph Chung, Dave Anglin, Andreas Tobler | |
312 | powerpc Geoffrey Keating, Andreas Tobler, | |
313 | David Edelsohn, John Hornkvist | |
314 | powerpc64 Jakub Jelinek | |
315 | s390 Gerhard Tonn, Ulrich Weigand | |
316 | sh Kaz Kojima | |
317 | sh64 Kaz Kojima | |
318 | sparc Anthony Green, Gordon Irlam | |
319 | x86 Anthony Green, Jon Beniston | |
320 | x86-64 Bo Thorsen | |
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321 | |
322 | Jesper Skov and Andrew Haley both did more than their fair share of | |
323 | stepping through the code and tracking down bugs. | |
324 | ||
491e6ad1 AH |
325 | Thanks also to Tom Tromey for bug fixes, documentation and |
326 | configuration help. | |
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327 | |
328 | Thanks to Jim Blandy, who provided some useful feedback on the libffi | |
329 | interface. | |
330 | ||
491e6ad1 AH |
331 | Andreas Tobler has done a tremendous amount of work on the testsuite. |
332 | ||
333 | Alex Oliva solved the executable page problem for SElinux. | |
334 | ||
335 | The list above is almost certainly incomplete and inaccurate. I'm | |
336 | happy to make corrections or additions upon request. | |
337 | ||
63e5e3e0 | 338 | If you have a problem, or have found a bug, please send a note to |
491e6ad1 | 339 | green@redhat.com. |