Anthony Green | c6dddbd | 2009-10-04 08:11:33 -0400 | [diff] [blame^] | 1 | This directory contains the libffi package, which is not part of GCC but |
| 2 | shipped with GCC as convenience. |
| 3 | |
| 4 | Status |
| 5 | ====== |
| 6 | |
| 7 | libffi-3.0.8 was released on December 19, 2008. Check the libffi web |
| 8 | page for updates: <URL:http://sourceware.org/libffi/>. |
| 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 | |
| 33 | FFI stands for Foreign Function Interface. A foreign function |
| 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 | |
| 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 mingw |
| 65 | x86-64 darwin |
| 66 | x86-64 linux |
| 67 | x86-64 OS X |
| 68 | x86-64 freebsd |
| 69 | x86-64 solaris |
| 70 | |
| 71 | Please send additional platform test results to |
| 72 | libffi-discuss@sourceware.org. |
| 73 | |
| 74 | Installing libffi |
| 75 | ================= |
| 76 | |
| 77 | [Note: before actually performing any of these installation steps, |
| 78 | you may wish to read the "Platform Specific Notes" below.] |
| 79 | |
| 80 | First you must configure the distribution for your particular |
| 81 | system. Go to the directory you wish to build libffi in and run the |
| 82 | "configure" program found in the root directory of the libffi source |
| 83 | distribution. |
| 84 | |
| 85 | You may want to tell configure where to install the libffi library and |
| 86 | header files. To do that, use the --prefix configure switch. Libffi |
| 87 | will install under /usr/local by default. |
| 88 | |
| 89 | If you want to enable extra run-time debugging checks use the the |
| 90 | --enable-debug configure switch. This is useful when your program dies |
| 91 | mysteriously while using libffi. |
| 92 | |
| 93 | Another useful configure switch is --enable-purify-safety. Using this |
| 94 | will add some extra code which will suppress certain warnings when you |
| 95 | are using Purify with libffi. Only use this switch when using |
| 96 | Purify, as it will slow down the library. |
| 97 | |
| 98 | Configure has many other options. Use "configure --help" to see them all. |
| 99 | |
| 100 | Once configure has finished, type "make". Note that you must be using |
| 101 | GNU make. You can ftp GNU make from prep.ai.mit.edu:/pub/gnu. |
| 102 | |
| 103 | To ensure that libffi is working as advertised, type "make check". |
| 104 | This will require that you have DejaGNU installed. |
| 105 | |
| 106 | To install the library and header files, type "make install". |
| 107 | |
| 108 | |
| 109 | Platform Specific Notes |
| 110 | ======================= |
| 111 | |
| 112 | MIPS - Irix 5.3 & 6.x |
| 113 | --------------------- |
| 114 | |
| 115 | Irix 6.2 and better supports three different calling conventions: o32, |
| 116 | n32 and n64. Currently, libffi only supports both o32 and n32 under |
| 117 | Irix 6.x, but only o32 under Irix 5.3. Libffi will automatically be |
| 118 | configured for whichever calling convention it was built for. |
| 119 | |
| 120 | By default, the configure script will try to build libffi with the GNU |
| 121 | development tools. To build libffi with the SGI development tools, set |
| 122 | the environment variable CC to either "cc -32" or "cc -n32" before |
| 123 | running configure under Irix 6.x (depending on whether you want an o32 |
| 124 | or n32 library), or just "cc" for Irix 5.3. |
| 125 | |
| 126 | With the n32 calling convention, when returning structures smaller |
| 127 | than 16 bytes, be sure to provide an RVALUE that is 8 byte aligned. |
| 128 | Here's one way of forcing this: |
| 129 | |
| 130 | double struct_storage[2]; |
| 131 | my_small_struct *s = (my_small_struct *) struct_storage; |
| 132 | /* Use s for RVALUE */ |
| 133 | |
| 134 | If you don't do this you are liable to get spurious bus errors. |
| 135 | |
| 136 | "long long" values are not supported yet. |
| 137 | |
| 138 | You must use GNU Make to build libffi on SGI platforms. |
| 139 | |
| 140 | |
| 141 | PowerPC System V ABI |
| 142 | -------------------- |
| 143 | |
| 144 | There are two `System V ABI's which libffi implements for PowerPC. |
| 145 | They differ only in how small structures are returned from functions. |
| 146 | |
| 147 | In the FFI_SYSV version, structures that are 8 bytes or smaller are |
| 148 | returned in registers. This is what GCC does when it is configured |
| 149 | for solaris, and is what the System V ABI I have (dated September |
| 150 | 1995) says. |
| 151 | |
| 152 | In the FFI_GCC_SYSV version, all structures are returned the same way: |
| 153 | by passing a pointer as the first argument to the function. This is |
| 154 | what GCC does when it is configured for linux or a generic sysv |
| 155 | target. |
| 156 | |
| 157 | EGCS 1.0.1 (and probably other versions of EGCS/GCC) also has a |
| 158 | inconsistency with the SysV ABI: When a procedure is called with many |
| 159 | floating-point arguments, some of them get put on the stack. They are |
| 160 | all supposed to be stored in double-precision format, even if they are |
| 161 | only single-precision, but EGCS stores single-precision arguments as |
| 162 | single-precision anyway. This causes one test to fail (the `many |
| 163 | arguments' test). |
| 164 | |
| 165 | |
| 166 | History |
| 167 | ======= |
| 168 | |
| 169 | 3.0.7 Nov-11-08 |
| 170 | Fix for ppc FreeBSD. |
| 171 | (thanks to Andreas Tobler) |
| 172 | |
| 173 | 3.0.6 Jul-17-08 |
| 174 | Fix for closures on sh. |
| 175 | Mark the sh/sh64 stack as non-executable. |
| 176 | (both thanks to Kaz Kojima) |
| 177 | |
| 178 | 3.0.5 Apr-3-08 |
| 179 | Fix libffi.pc file. |
| 180 | Fix #define ARM for IcedTea users. |
| 181 | Fix x86 closure bug. |
| 182 | |
| 183 | 3.0.4 Feb-24-08 |
| 184 | Fix x86 OpenBSD configury. |
| 185 | |
| 186 | 3.0.3 Feb-22-08 |
| 187 | Enable x86 OpenBSD thanks to Thomas Heller, and |
| 188 | x86-64 FreeBSD thanks to Björn König and Andreas Tobler. |
| 189 | Clean up test instruction in README. |
| 190 | |
| 191 | 3.0.2 Feb-21-08 |
| 192 | Improved x86 FreeBSD support. |
| 193 | Thanks to Björn König. |
| 194 | |
| 195 | 3.0.1 Feb-15-08 |
| 196 | Fix instruction cache flushing bug on MIPS. |
| 197 | Thanks to David Daney. |
| 198 | |
| 199 | 3.0.0 Feb-15-08 |
| 200 | Many changes, mostly thanks to the GCC project. |
| 201 | Cygnus Solutions is now Red Hat. |
| 202 | |
| 203 | [10 years go by...] |
| 204 | |
| 205 | 1.20 Oct-5-98 |
| 206 | Raffaele Sena produces ARM port. |
| 207 | |
| 208 | 1.19 Oct-5-98 |
| 209 | Fixed x86 long double and long long return support. |
| 210 | m68k bug fixes from Andreas Schwab. |
| 211 | Patch for DU assembler compatibility for the Alpha from Richard |
| 212 | Henderson. |
| 213 | |
| 214 | 1.18 Apr-17-98 |
| 215 | Bug fixes and MIPS configuration changes. |
| 216 | |
| 217 | 1.17 Feb-24-98 |
| 218 | Bug fixes and m68k port from Andreas Schwab. PowerPC port from |
| 219 | Geoffrey Keating. Various bug x86, Sparc and MIPS bug fixes. |
| 220 | |
| 221 | 1.16 Feb-11-98 |
| 222 | Richard Henderson produces Alpha port. |
| 223 | |
| 224 | 1.15 Dec-4-97 |
| 225 | Fixed an n32 ABI bug. New libtool, auto* support. |
| 226 | |
| 227 | 1.14 May-13-97 |
| 228 | libtool is now used to generate shared and static libraries. |
| 229 | Fixed a minor portability problem reported by Russ McManus |
| 230 | <mcmanr@eq.gs.com>. |
| 231 | |
| 232 | 1.13 Dec-2-96 |
| 233 | Added --enable-purify-safety to keep Purify from complaining |
| 234 | about certain low level code. |
| 235 | Sparc fix for calling functions with < 6 args. |
| 236 | Linux x86 a.out fix. |
| 237 | |
| 238 | 1.12 Nov-22-96 |
| 239 | Added missing ffi_type_void, needed for supporting void return |
| 240 | types. Fixed test case for non MIPS machines. Cygnus Support |
| 241 | is now Cygnus Solutions. |
| 242 | |
| 243 | 1.11 Oct-30-96 |
| 244 | Added notes about GNU make. |
| 245 | |
| 246 | 1.10 Oct-29-96 |
| 247 | Added configuration fix for non GNU compilers. |
| 248 | |
| 249 | 1.09 Oct-29-96 |
| 250 | Added --enable-debug configure switch. Clean-ups based on LCLint |
| 251 | feedback. ffi_mips.h is always installed. Many configuration |
| 252 | fixes. Fixed ffitest.c for sparc builds. |
| 253 | |
| 254 | 1.08 Oct-15-96 |
| 255 | Fixed n32 problem. Many clean-ups. |
| 256 | |
| 257 | 1.07 Oct-14-96 |
| 258 | Gordon Irlam rewrites v8.S again. Bug fixes. |
| 259 | |
| 260 | 1.06 Oct-14-96 |
| 261 | Gordon Irlam improved the sparc port. |
| 262 | |
| 263 | 1.05 Oct-14-96 |
| 264 | Interface changes based on feedback. |
| 265 | |
| 266 | 1.04 Oct-11-96 |
| 267 | Sparc port complete (modulo struct passing bug). |
| 268 | |
| 269 | 1.03 Oct-10-96 |
| 270 | Passing struct args, and returning struct values works for |
| 271 | all architectures/calling conventions. Expanded tests. |
| 272 | |
| 273 | 1.02 Oct-9-96 |
| 274 | Added SGI n32 support. Fixed bugs in both o32 and Linux support. |
| 275 | Added "make test". |
| 276 | |
| 277 | 1.01 Oct-8-96 |
| 278 | Fixed float passing bug in mips version. Restructured some |
| 279 | of the code. Builds cleanly with SGI tools. |
| 280 | |
| 281 | 1.00 Oct-7-96 |
| 282 | First release. No public announcement. |
| 283 | |
| 284 | |
| 285 | Authors & Credits |
| 286 | ================= |
| 287 | |
| 288 | libffi was originally written by Anthony Green <green@redhat.com>. |
| 289 | |
| 290 | The developers of the GNU Compiler Collection project have made |
| 291 | innumerable valuable contributions. See the ChangeLog file for |
| 292 | details. |
| 293 | |
| 294 | Some of the ideas behind libffi were inspired by Gianni Mariani's free |
| 295 | gencall library for Silicon Graphics machines. |
| 296 | |
| 297 | The closure mechanism was designed and implemented by Kresten Krab |
| 298 | Thorup. |
| 299 | |
| 300 | Major processor architecture ports were contributed by the following |
| 301 | developers: |
| 302 | |
| 303 | alpha Richard Henderson |
| 304 | arm Raffaele Sena |
| 305 | cris Simon Posnjak, Hans-Peter Nilsson |
| 306 | frv Anthony Green |
| 307 | ia64 Hans Boehm |
| 308 | m32r Kazuhiro Inaoka |
| 309 | m68k Andreas Schwab |
| 310 | mips Anthony Green, Casey Marshall |
| 311 | mips64 David Daney |
| 312 | pa Randolph Chung, Dave Anglin, Andreas Tobler |
| 313 | powerpc Geoffrey Keating, Andreas Tobler, |
| 314 | David Edelsohn, John Hornkvist |
| 315 | powerpc64 Jakub Jelinek |
| 316 | s390 Gerhard Tonn, Ulrich Weigand |
| 317 | sh Kaz Kojima |
| 318 | sh64 Kaz Kojima |
| 319 | sparc Anthony Green, Gordon Irlam |
| 320 | x86 Anthony Green, Jon Beniston |
| 321 | x86-64 Bo Thorsen |
| 322 | |
| 323 | Jesper Skov and Andrew Haley both did more than their fair share of |
| 324 | stepping through the code and tracking down bugs. |
| 325 | |
| 326 | Thanks also to Tom Tromey for bug fixes, documentation and |
| 327 | configuration help. |
| 328 | |
| 329 | Thanks to Jim Blandy, who provided some useful feedback on the libffi |
| 330 | interface. |
| 331 | |
| 332 | Andreas Tobler has done a tremendous amount of work on the testsuite. |
| 333 | |
| 334 | Alex Oliva solved the executable page problem for SElinux. |
| 335 | |
| 336 | The list above is almost certainly incomplete and inaccurate. I'm |
| 337 | happy to make corrections or additions upon request. |
| 338 | |
| 339 | If you have a problem, or have found a bug, please send a note to |
| 340 | green@redhat.com. |