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