configure.html revision 1.1.1.20
1 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2 <html> 3 <!-- Created by GNU Texinfo 6.8, https://www.gnu.org/software/texinfo/ --> 4 <head> 5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> 6 <!-- Copyright (C) 1988-2022 Free Software Foundation, Inc. 7 8 Permission is granted to copy, distribute and/or modify this document 9 under the terms of the GNU Free Documentation License, Version 1.3 or 10 any later version published by the Free Software Foundation; with no 11 Invariant Sections, the Front-Cover texts being (a) (see below), and 12 with the Back-Cover Texts being (b) (see below). A copy of the 13 license is included in the section entitled "GNU 14 Free Documentation License". 15 16 (a) The FSF's Front-Cover Text is: 17 18 A GNU Manual 19 20 (b) The FSF's Back-Cover Text is: 21 22 You have freedom to copy and modify this GNU Manual, like GNU 23 software. Copies published by the Free Software Foundation raise 24 funds for GNU development. --> 25 <title>Installing GCC: Configuration</title> 26 27 <meta name="description" content="Installing GCC: Configuration"> 28 <meta name="keywords" content="Installing GCC: Configuration"> 29 <meta name="resource-type" content="document"> 30 <meta name="distribution" content="global"> 31 <meta name="Generator" content="makeinfo"> 32 <meta name="viewport" content="width=device-width,initial-scale=1"> 33 34 <style type="text/css"> 35 <!-- 36 a.copiable-anchor {visibility: hidden; text-decoration: none; line-height: 0em} 37 a.summary-letter {text-decoration: none} 38 blockquote.indentedblock {margin-right: 0em} 39 div.display {margin-left: 3.2em} 40 div.example {margin-left: 3.2em} 41 kbd {font-style: oblique} 42 pre.display {font-family: inherit} 43 pre.format {font-family: inherit} 44 pre.menu-comment {font-family: serif} 45 pre.menu-preformatted {font-family: serif} 46 span.nolinebreak {white-space: nowrap} 47 span.roman {font-family: initial; font-weight: normal} 48 span.sansserif {font-family: sans-serif; font-weight: normal} 49 span:hover a.copiable-anchor {visibility: visible} 50 ul.no-bullet {list-style: none} 51 --> 52 </style> 53 54 55 </head> 56 57 <body lang="en"> 58 <h1 class="settitle" align="center">Installing GCC: Configuration</h1> 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 <span id="index-Configuration"></span> 79 <span id="index-Installing-GCC_003a-Configuration"></span> 80 81 <p>Like most GNU software, GCC must be configured before it can be built. 82 This document describes the recommended configuration procedure 83 for both native and cross targets. 84 </p> 85 <p>We use <var>srcdir</var> to refer to the toplevel source directory for 86 GCC; we use <var>objdir</var> to refer to the toplevel build/object directory. 87 </p> 88 <p>If you obtained the sources by cloning the repository, <var>srcdir</var> 89 must refer to the top <samp>gcc</samp> directory, the one where the 90 <samp>MAINTAINERS</samp> file can be found, and not its <samp>gcc</samp> 91 subdirectory, otherwise the build will fail. 92 </p> 93 <p>If either <var>srcdir</var> or <var>objdir</var> is located on an automounted NFS 94 file system, the shell’s built-in <code>pwd</code> command will return 95 temporary pathnames. Using these can lead to various sorts of build 96 problems. To avoid this issue, set the <code>PWDCMD</code> environment 97 variable to an automounter-aware <code>pwd</code> command, e.g., 98 <code>pawd</code> or ‘<samp>amq -w</samp>’, during the configuration and build 99 phases. 100 </p> 101 <p>First, we <strong>highly</strong> recommend that GCC be built into a 102 separate directory from the sources which does <strong>not</strong> reside 103 within the source tree. This is how we generally build GCC; building 104 where <var>srcdir</var> == <var>objdir</var> should still work, but doesn’t 105 get extensive testing; building where <var>objdir</var> is a subdirectory 106 of <var>srcdir</var> is unsupported. 107 </p> 108 <p>If you have previously built GCC in the same directory for a 109 different target machine, do ‘<samp>make distclean</samp>’ to delete all files 110 that might be invalid. One of the files this deletes is <samp>Makefile</samp>; 111 if ‘<samp>make distclean</samp>’ complains that <samp>Makefile</samp> does not exist 112 or issues a message like “don’t know how to make distclean” it probably 113 means that the directory is already suitably clean. However, with the 114 recommended method of building in a separate <var>objdir</var>, you should 115 simply use a different <var>objdir</var> for each target. 116 </p> 117 <p>Second, when configuring a native system, either <code>cc</code> or 118 <code>gcc</code> must be in your path or you must set <code>CC</code> in 119 your environment before running configure. Otherwise the configuration 120 scripts may fail. 121 </p> 122 123 <p>To configure GCC: 124 </p> 125 <div class="example"> 126 <pre class="example">% mkdir <var>objdir</var> 127 % cd <var>objdir</var> 128 % <var>srcdir</var>/configure [<var>options</var>] [<var>target</var>] 129 </pre></div> 130 131 <span id="Distributor-options"></span><h3 class="heading">Distributor options</h3> 132 133 <p>If you will be distributing binary versions of GCC, with modifications 134 to the source code, you should use the options described in this 135 section to make clear that your version contains modifications. 136 </p> 137 <dl compact="compact"> 138 <dt><span><code>--with-pkgversion=<var>version</var></code></span></dt> 139 <dd><p>Specify a string that identifies your package. You may wish 140 to include a build number or build date. This version string will be 141 included in the output of <code>gcc --version</code>. This suffix does 142 not replace the default version string, only the ‘<samp>GCC</samp>’ part. 143 </p> 144 <p>The default value is ‘<samp>GCC</samp>’. 145 </p> 146 </dd> 147 <dt><span><code>--with-bugurl=<var>url</var></code></span></dt> 148 <dd><p>Specify the URL that users should visit if they wish to report a bug. 149 You are of course welcome to forward bugs reported to you to the FSF, 150 if you determine that they are not bugs in your modifications. 151 </p> 152 <p>The default value refers to the FSF’s GCC bug tracker. 153 </p> 154 </dd> 155 <dt><span><code>--with-documentation-root-url=<var>url</var></code></span></dt> 156 <dd><p>Specify the URL root that contains GCC option documentation. The <var>url</var> 157 should end with a <code>/</code> character. 158 </p> 159 <p>The default value is <a href="https://gcc.gnu.org/onlinedocs/">https://gcc.gnu.org/onlinedocs/</a>. 160 </p> 161 </dd> 162 <dt><span><code>--with-changes-root-url=<var>url</var></code></span></dt> 163 <dd><p>Specify the URL root that contains information about changes in GCC 164 releases like <code>gcc-<var>version</var>/changes.html</code>. 165 The <var>url</var> should end with a <code>/</code> character. 166 </p> 167 <p>The default value is <a href="https://gcc.gnu.org/">https://gcc.gnu.org/</a>. 168 </p> 169 </dd> 170 </dl> 171 172 <span id="Host_002c-Build-and-Target-specification"></span><h3 class="heading">Host, Build and Target specification</h3> 173 174 <p>Specify the host, build and target machine configurations. You do this 175 when you run the <samp>configure</samp> script. 176 </p> 177 <p>The <em>build</em> machine is the system which you are using, the 178 <em>host</em> machine is the system where you want to run the resulting 179 compiler (normally the build machine), and the <em>target</em> machine is 180 the system for which you want the compiler to generate code. 181 </p> 182 <p>If you are building a compiler to produce code for the machine it runs 183 on (a native compiler), you normally do not need to specify any operands 184 to <samp>configure</samp>; it will try to guess the type of machine you are on 185 and use that as the build, host and target machines. So you don’t need 186 to specify a configuration when building a native compiler unless 187 <samp>configure</samp> cannot figure out what your configuration is or guesses 188 wrong. 189 </p> 190 <p>In those cases, specify the build machine’s <em>configuration name</em> 191 with the <samp>--host</samp> option; the host and target will default to be 192 the same as the host machine. 193 </p> 194 <p>Here is an example: 195 </p> 196 <div class="example"> 197 <pre class="example">./configure --host=x86_64-pc-linux-gnu 198 </pre></div> 199 200 <p>A configuration name may be canonical or it may be more or less 201 abbreviated (<samp>config.sub</samp> script produces canonical versions). 202 </p> 203 <p>A canonical configuration name has three parts, separated by dashes. 204 It looks like this: ‘<samp><var>cpu</var>-<var>company</var>-<var>system</var></samp>’. 205 </p> 206 <p>Here are the possible CPU types: 207 </p> 208 <blockquote> 209 <p>aarch64, aarch64_be, alpha, alpha64, amdgcn, arc, arceb, arm, armeb, avr, bfin, 210 bpf, cr16, cris, csky, epiphany, fido, fr30, frv, ft32, h8300, hppa, hppa2.0, 211 hppa64, i486, i686, ia64, iq2000, lm32, loongarch64, m32c, m32r, m32rle, m68k, 212 mcore, microblaze, microblazeel, mips, mips64, mips64el, mips64octeon, 213 mips64orion, mips64vr, mipsel, mipsisa32, mipsisa32r2, mipsisa64, mipsisa64r2, 214 mipsisa64r2el, mipsisa64sb1, mipsisa64sr71k, mipstx39, mmix, mn10300, moxie, 215 msp430, nds32be, nds32le, nios2, nvptx, or1k, pdp11, powerpc, powerpc64, 216 powerpc64le, powerpcle, pru, riscv32, riscv32be, riscv64, riscv64be, rl78, rx, 217 s390, s390x, sh, shle, sparc, sparc64, tic6x, tilegx, tilegxbe, tilepro, v850, 218 v850e, v850e1, vax, visium, x86_64, xstormy16, xtensa 219 </p></blockquote> 220 221 <p>Here is a list of system types: 222 </p> 223 <blockquote> 224 <p>aix<var>version</var>, amdhsa, aout, cygwin, darwin<var>version</var>, 225 eabi, eabialtivec, eabisim, eabisimaltivec, elf, elf32, 226 elfbare, elfoabi, freebsd<var>version</var>, gnu, hpux, hpux<var>version</var>, 227 kfreebsd-gnu, kopensolaris-gnu, linux-androideabi, linux-gnu, 228 linux-gnu_altivec, linux-musl, linux-uclibc, lynxos, mingw32, mingw32crt, 229 mmixware, msdosdjgpp, netbsd, netbsdelf<var>version</var>, nto-qnx, openbsd, 230 rtems, solaris<var>version</var>, symbianelf, tpf, uclinux, uclinux_eabi, vms, 231 vxworks, vxworksae, vxworksmils 232 </p></blockquote> 233 234 <span id="Options-specification"></span><h3 class="heading">Options specification</h3> 235 236 <p>Use <var>options</var> to override several configure time options for 237 GCC. A list of supported <var>options</var> follows; ‘<samp>configure 238 --help</samp>’ may list other options, but those not listed below may not 239 work and should not normally be used. 240 </p> 241 <p>Note that each <samp>--enable</samp> option has a corresponding 242 <samp>--disable</samp> option and that each <samp>--with</samp> option has a 243 corresponding <samp>--without</samp> option. 244 </p> 245 <dl compact="compact"> 246 <dt><span><code>--prefix=<var>dirname</var></code></span></dt> 247 <dd><p>Specify the toplevel installation 248 directory. This is the recommended way to install the tools into a directory 249 other than the default. The toplevel installation directory defaults to 250 <samp>/usr/local</samp>. 251 </p> 252 <p>We <strong>highly</strong> recommend against <var>dirname</var> being the same or a 253 subdirectory of <var>objdir</var> or vice versa. If specifying a directory 254 beneath a user’s home directory tree, some shells will not expand 255 <var>dirname</var> correctly if it contains the ‘<samp>~</samp>’ metacharacter; use 256 <code>$HOME</code> instead. 257 </p> 258 <p>The following standard <code>autoconf</code> options are supported. Normally you 259 should not need to use these options. 260 </p><dl compact="compact"> 261 <dt><span><code>--exec-prefix=<var>dirname</var></code></span></dt> 262 <dd><p>Specify the toplevel installation directory for architecture-dependent 263 files. The default is <samp><var>prefix</var></samp>. 264 </p> 265 </dd> 266 <dt><span><code>--bindir=<var>dirname</var></code></span></dt> 267 <dd><p>Specify the installation directory for the executables called by users 268 (such as <code>gcc</code> and <code>g++</code>). The default is 269 <samp><var>exec-prefix</var>/bin</samp>. 270 </p> 271 </dd> 272 <dt><span><code>--libdir=<var>dirname</var></code></span></dt> 273 <dd><p>Specify the installation directory for object code libraries and 274 internal data files of GCC. The default is <samp><var>exec-prefix</var>/lib</samp>. 275 </p> 276 </dd> 277 <dt><span><code>--libexecdir=<var>dirname</var></code></span></dt> 278 <dd><p>Specify the installation directory for internal executables of GCC. 279 The default is <samp><var>exec-prefix</var>/libexec</samp>. 280 </p> 281 </dd> 282 <dt><span><code>--with-slibdir=<var>dirname</var></code></span></dt> 283 <dd><p>Specify the installation directory for the shared libgcc library. The 284 default is <samp><var>libdir</var></samp>. 285 </p> 286 </dd> 287 <dt><span><code>--datarootdir=<var>dirname</var></code></span></dt> 288 <dd><p>Specify the root of the directory tree for read-only architecture-independent 289 data files referenced by GCC. The default is <samp><var>prefix</var>/share</samp>. 290 </p> 291 </dd> 292 <dt><span><code>--infodir=<var>dirname</var></code></span></dt> 293 <dd><p>Specify the installation directory for documentation in info format. 294 The default is <samp><var>datarootdir</var>/info</samp>. 295 </p> 296 </dd> 297 <dt><span><code>--datadir=<var>dirname</var></code></span></dt> 298 <dd><p>Specify the installation directory for some architecture-independent 299 data files referenced by GCC. The default is <samp><var>datarootdir</var></samp>. 300 </p> 301 </dd> 302 <dt><span><code>--docdir=<var>dirname</var></code></span></dt> 303 <dd><p>Specify the installation directory for documentation files (other 304 than Info) for GCC. The default is <samp><var>datarootdir</var>/doc</samp>. 305 </p> 306 </dd> 307 <dt><span><code>--htmldir=<var>dirname</var></code></span></dt> 308 <dd><p>Specify the installation directory for HTML documentation files. 309 The default is <samp><var>docdir</var></samp>. 310 </p> 311 </dd> 312 <dt><span><code>--pdfdir=<var>dirname</var></code></span></dt> 313 <dd><p>Specify the installation directory for PDF documentation files. 314 The default is <samp><var>docdir</var></samp>. 315 </p> 316 </dd> 317 <dt><span><code>--mandir=<var>dirname</var></code></span></dt> 318 <dd><p>Specify the installation directory for manual pages. The default is 319 <samp><var>datarootdir</var>/man</samp>. (Note that the manual pages are only extracts 320 from the full GCC manuals, which are provided in Texinfo format. The manpages 321 are derived by an automatic conversion process from parts of the full 322 manual.) 323 </p> 324 </dd> 325 <dt><span><code>--with-gxx-include-dir=<var>dirname</var></code></span></dt> 326 <dd><p>Specify 327 the installation directory for G++ header files. The default depends 328 on other configuration options, and differs between cross and native 329 configurations. 330 </p> 331 </dd> 332 <dt><span><code>--with-specs=<var>specs</var></code></span></dt> 333 <dd><p>Specify additional command line driver SPECS. 334 This can be useful if you need to turn on a non-standard feature by 335 default without modifying the compiler’s source code, for instance 336 <samp>--with-specs=%{!fcommon:%{!fno-common:-fno-common}}</samp>. 337 See “Spec Files” in the main manual 338 </p> 339 </dd> 340 </dl> 341 342 </dd> 343 <dt><span><code>--program-prefix=<var>prefix</var></code></span></dt> 344 <dd><p>GCC supports some transformations of the names of its programs when 345 installing them. This option prepends <var>prefix</var> to the names of 346 programs to install in <var>bindir</var> (see above). For example, specifying 347 <samp>--program-prefix=foo-</samp> would result in ‘<samp>gcc</samp>’ 348 being installed as <samp>/usr/local/bin/foo-gcc</samp>. 349 </p> 350 </dd> 351 <dt><span><code>--program-suffix=<var>suffix</var></code></span></dt> 352 <dd><p>Appends <var>suffix</var> to the names of programs to install in <var>bindir</var> 353 (see above). For example, specifying <samp>--program-suffix=-3.1</samp> 354 would result in ‘<samp>gcc</samp>’ being installed as 355 <samp>/usr/local/bin/gcc-3.1</samp>. 356 </p> 357 </dd> 358 <dt><span><code>--program-transform-name=<var>pattern</var></code></span></dt> 359 <dd><p>Applies the ‘<samp>sed</samp>’ script <var>pattern</var> to be applied to the names 360 of programs to install in <var>bindir</var> (see above). <var>pattern</var> has to 361 consist of one or more basic ‘<samp>sed</samp>’ editing commands, separated by 362 semicolons. For example, if you want the ‘<samp>gcc</samp>’ program name to be 363 transformed to the installed program <samp>/usr/local/bin/myowngcc</samp> and 364 the ‘<samp>g++</samp>’ program name to be transformed to 365 <samp>/usr/local/bin/gspecial++</samp> without changing other program names, 366 you could use the pattern 367 <samp>--program-transform-name='s/^gcc$/myowngcc/; s/^g++$/gspecial++/'</samp> 368 to achieve this effect. 369 </p> 370 <p>All three options can be combined and used together, resulting in more 371 complex conversion patterns. As a basic rule, <var>prefix</var> (and 372 <var>suffix</var>) are prepended (appended) before further transformations 373 can happen with a special transformation script <var>pattern</var>. 374 </p> 375 <p>As currently implemented, this option only takes effect for native 376 builds; cross compiler binaries’ names are not transformed even when a 377 transformation is explicitly asked for by one of these options. 378 </p> 379 <p>For native builds, some of the installed programs are also installed 380 with the target alias in front of their name, as in 381 ‘<samp>i686-pc-linux-gnu-gcc</samp>’. All of the above transformations happen 382 before the target alias is prepended to the name—so, specifying 383 <samp>--program-prefix=foo-</samp> and <samp>program-suffix=-3.1</samp>, the 384 resulting binary would be installed as 385 <samp>/usr/local/bin/i686-pc-linux-gnu-foo-gcc-3.1</samp>. 386 </p> 387 <p>As a last shortcoming, none of the installed Ada programs are 388 transformed yet, which will be fixed in some time. 389 </p> 390 </dd> 391 <dt><span><code>--with-local-prefix=<var>dirname</var></code></span></dt> 392 <dd><p>Specify the 393 installation directory for local include files. The default is 394 <samp>/usr/local</samp>. Specify this option if you want the compiler to 395 search directory <samp><var>dirname</var>/include</samp> for locally installed 396 header files <em>instead</em> of <samp>/usr/local/include</samp>. 397 </p> 398 <p>You should specify <samp>--with-local-prefix</samp> <strong>only</strong> if your 399 site has a different convention (not <samp>/usr/local</samp>) for where to put 400 site-specific files. 401 </p> 402 <p>The default value for <samp>--with-local-prefix</samp> is <samp>/usr/local</samp> 403 regardless of the value of <samp>--prefix</samp>. Specifying 404 <samp>--prefix</samp> has no effect on which directory GCC searches for 405 local header files. This may seem counterintuitive, but actually it is 406 logical. 407 </p> 408 <p>The purpose of <samp>--prefix</samp> is to specify where to <em>install 409 GCC</em>. The local header files in <samp>/usr/local/include</samp>—if you put 410 any in that directory—are not part of GCC. They are part of other 411 programs—perhaps many others. (GCC installs its own header files in 412 another directory which is based on the <samp>--prefix</samp> value.) 413 </p> 414 <p>Both the local-prefix include directory and the GCC-prefix include 415 directory are part of GCC’s “system include” directories. Although these 416 two directories are not fixed, they need to be searched in the proper 417 order for the correct processing of the include_next directive. The 418 local-prefix include directory is searched before the GCC-prefix 419 include directory. Another characteristic of system include directories 420 is that pedantic warnings are turned off for headers in these directories. 421 </p> 422 <p>Some autoconf macros add <samp>-I <var>directory</var></samp> options to the 423 compiler command line, to ensure that directories containing installed 424 packages’ headers are searched. When <var>directory</var> is one of GCC’s 425 system include directories, GCC will ignore the option so that system 426 directories continue to be processed in the correct order. This 427 may result in a search order different from what was specified but the 428 directory will still be searched. 429 </p> 430 <p>GCC automatically searches for ordinary libraries using 431 <code>GCC_EXEC_PREFIX</code>. Thus, when the same installation prefix is 432 used for both GCC and packages, GCC will automatically search for 433 both headers and libraries. This provides a configuration that is 434 easy to use. GCC behaves in a manner similar to that when it is 435 installed as a system compiler in <samp>/usr</samp>. 436 </p> 437 <p>Sites that need to install multiple versions of GCC may not want to 438 use the above simple configuration. It is possible to use the 439 <samp>--program-prefix</samp>, <samp>--program-suffix</samp> and 440 <samp>--program-transform-name</samp> options to install multiple versions 441 into a single directory, but it may be simpler to use different prefixes 442 and the <samp>--with-local-prefix</samp> option to specify the location of the 443 site-specific files for each version. It will then be necessary for 444 users to specify explicitly the location of local site libraries 445 (e.g., with <code>LIBRARY_PATH</code>). 446 </p> 447 <p>The same value can be used for both <samp>--with-local-prefix</samp> and 448 <samp>--prefix</samp> provided it is not <samp>/usr</samp>. This can be used 449 to avoid the default search of <samp>/usr/local/include</samp>. 450 </p> 451 <p><strong>Do not</strong> specify <samp>/usr</samp> as the <samp>--with-local-prefix</samp>! 452 The directory you use for <samp>--with-local-prefix</samp> <strong>must not</strong> 453 contain any of the system’s standard header files. If it did contain 454 them, certain programs would be miscompiled (including GNU Emacs, on 455 certain targets), because this would override and nullify the header 456 file corrections made by the <code>fixincludes</code> script. 457 </p> 458 <p>Indications are that people who use this option use it based on mistaken 459 ideas of what it is for. People use it as if it specified where to 460 install part of GCC. Perhaps they make this assumption because 461 installing GCC creates the directory. 462 </p> 463 </dd> 464 <dt><span><code>--with-gcc-major-version-only</code></span></dt> 465 <dd><p>Specifies that GCC should use only the major number rather than 466 <var>major</var>.<var>minor</var>.<var>patchlevel</var> in filesystem paths. 467 </p> 468 </dd> 469 <dt><span><code>--with-native-system-header-dir=<var>dirname</var></code></span></dt> 470 <dd><p>Specifies that <var>dirname</var> is the directory that contains native system 471 header files, rather than <samp>/usr/include</samp>. This option is most useful 472 if you are creating a compiler that should be isolated from the system 473 as much as possible. It is most commonly used with the 474 <samp>--with-sysroot</samp> option and will cause GCC to search 475 <var>dirname</var> inside the system root specified by that option. 476 </p> 477 </dd> 478 <dt><span><code>--enable-shared[=<var>package</var>[,…]]</code></span></dt> 479 <dd><p>Build shared versions of libraries, if shared libraries are supported on 480 the target platform. Unlike GCC 2.95.x and earlier, shared libraries 481 are enabled by default on all platforms that support shared libraries. 482 </p> 483 <p>If a list of packages is given as an argument, build shared libraries 484 only for the listed packages. For other packages, only static libraries 485 will be built. Package names currently recognized in the GCC tree are 486 ‘<samp>libgcc</samp>’ (also known as ‘<samp>gcc</samp>’), ‘<samp>libstdc++</samp>’ (not 487 ‘<samp>libstdc++-v3</samp>’), ‘<samp>libffi</samp>’, ‘<samp>zlib</samp>’, ‘<samp>boehm-gc</samp>’, 488 ‘<samp>ada</samp>’, ‘<samp>libada</samp>’, ‘<samp>libgo</samp>’, ‘<samp>libobjc</samp>’, and ‘<samp>libphobos</samp>’. 489 Note ‘<samp>libiberty</samp>’ does not support shared libraries at all. 490 </p> 491 <p>Use <samp>--disable-shared</samp> to build only static libraries. Note that 492 <samp>--disable-shared</samp> does not accept a list of package names as 493 argument, only <samp>--enable-shared</samp> does. 494 </p> 495 <p>Contrast with <samp>--enable-host-shared</samp>, which affects <em>host</em> 496 code. 497 </p> 498 </dd> 499 <dt><span><code>--enable-host-shared</code></span></dt> 500 <dd><p>Specify that the <em>host</em> code should be built into position-independent 501 machine code (with -fPIC), allowing it to be used within shared libraries, 502 but yielding a slightly slower compiler. 503 </p> 504 <p>This option is required when building the libgccjit.so library. 505 </p> 506 <p>Contrast with <samp>--enable-shared</samp>, which affects <em>target</em> 507 libraries. 508 </p> 509 </dd> 510 <dt><span><code><span id="with-gnu-as"></span>--with-gnu-as</code></span></dt> 511 <dd><p>Specify that the compiler should assume that the 512 assembler it finds is the GNU assembler. However, this does not modify 513 the rules to find an assembler and will result in confusion if the 514 assembler found is not actually the GNU assembler. (Confusion may also 515 result if the compiler finds the GNU assembler but has not been 516 configured with <samp>--with-gnu-as</samp>.) If you have more than one 517 assembler installed on your system, you may want to use this option in 518 connection with <samp>--with-as=<var>pathname</var></samp> or 519 <samp>--with-build-time-tools=<var>pathname</var></samp>. 520 </p> 521 <p>The following systems are the only ones where it makes a difference 522 whether you use the GNU assembler. On any other system, 523 <samp>--with-gnu-as</samp> has no effect. 524 </p> 525 <ul> 526 <li> ‘<samp>hppa1.0-<var>any</var>-<var>any</var></samp>’ 527 </li><li> ‘<samp>hppa1.1-<var>any</var>-<var>any</var></samp>’ 528 </li><li> ‘<samp>sparc-sun-solaris2.<var>any</var></samp>’ 529 </li><li> ‘<samp>sparc64-<var>any</var>-solaris2.<var>any</var></samp>’ 530 </li></ul> 531 532 </dd> 533 <dt><span><code><span id="with-as"></span>--with-as=<var>pathname</var></code></span></dt> 534 <dd><p>Specify that the compiler should use the assembler pointed to by 535 <var>pathname</var>, rather than the one found by the standard rules to find 536 an assembler, which are: 537 </p><ul> 538 <li> Unless GCC is being built with a cross compiler, check the 539 <samp><var>libexec</var>/gcc/<var>target</var>/<var>version</var></samp> directory. 540 <var>libexec</var> defaults to <samp><var>exec-prefix</var>/libexec</samp>; 541 <var>exec-prefix</var> defaults to <var>prefix</var>, which 542 defaults to <samp>/usr/local</samp> unless overridden by the 543 <samp>--prefix=<var>pathname</var></samp> switch described above. <var>target</var> 544 is the target system triple, such as ‘<samp>sparc-sun-solaris2.7</samp>’, and 545 <var>version</var> denotes the GCC version, such as 3.0. 546 547 </li><li> If the target system is the same that you are building on, check 548 operating system specific directories (e.g. <samp>/usr/ccs/bin</samp> on 549 Solaris 2). 550 551 </li><li> Check in the <code>PATH</code> for a tool whose name is prefixed by the 552 target system triple. 553 554 </li><li> Check in the <code>PATH</code> for a tool whose name is not prefixed by the 555 target system triple, if the host and target system triple are 556 the same (in other words, we use a host tool if it can be used for 557 the target as well). 558 </li></ul> 559 560 <p>You may want to use <samp>--with-as</samp> if no assembler 561 is installed in the directories listed above, or if you have multiple 562 assemblers installed and want to choose one that is not found by the 563 above rules. 564 </p> 565 </dd> 566 <dt><span><code><span id="with-gnu-ld"></span>--with-gnu-ld</code></span></dt> 567 <dd><p>Same as <a href="#with-gnu-as"><samp>--with-gnu-as</samp></a> 568 but for the linker. 569 </p> 570 </dd> 571 <dt><span><code>--with-ld=<var>pathname</var></code></span></dt> 572 <dd><p>Same as <a href="#with-as"><samp>--with-as</samp></a> 573 but for the linker. 574 </p> 575 </dd> 576 <dt><span><code>--with-dsymutil=<var>pathname</var></code></span></dt> 577 <dd><p>Same as <a href="#with-as"><samp>--with-as</samp></a> 578 but for the debug linker (only used on Darwin platforms so far). 579 </p> 580 </dd> 581 <dt><span><code>--with-tls=<var>dialect</var></code></span></dt> 582 <dd><p>Specify the default TLS dialect, for systems were there is a choice. 583 For ARM targets, possible values for <var>dialect</var> are <code>gnu</code> or 584 <code>gnu2</code>, which select between the original GNU dialect and the GNU TLS 585 descriptor-based dialect. 586 </p> 587 </dd> 588 <dt><span><code>--enable-multiarch</code></span></dt> 589 <dd><p>Specify whether to enable or disable multiarch support. The default is 590 to check for glibc start files in a multiarch location, and enable it 591 if the files are found. The auto detection is enabled for native builds, 592 and for cross builds configured with <samp>--with-sysroot</samp>, and without 593 <samp>--with-native-system-header-dir</samp>. 594 More documentation about multiarch can be found at 595 <a href="https://wiki.debian.org/Multiarch">https://wiki.debian.org/Multiarch</a>. 596 </p> 597 </dd> 598 <dt><span><code>--enable-sjlj-exceptions</code></span></dt> 599 <dd><p>Force use of the <code>setjmp</code>/<code>longjmp</code>-based scheme for exceptions. 600 ‘<samp>configure</samp>’ ordinarily picks the correct value based on the platform. 601 Only use this option if you are sure you need a different setting. 602 </p> 603 </dd> 604 <dt><span><code>--enable-vtable-verify</code></span></dt> 605 <dd><p>Specify whether to enable or disable the vtable verification feature. 606 Enabling this feature causes libstdc++ to be built with its virtual calls 607 in verifiable mode. This means that, when linked with libvtv, every 608 virtual call in libstdc++ will verify the vtable pointer through which the 609 call will be made before actually making the call. If not linked with libvtv, 610 the verifier will call stub functions (in libstdc++ itself) and do nothing. 611 If vtable verification is disabled, then libstdc++ is not built with its 612 virtual calls in verifiable mode at all. However the libvtv library will 613 still be built (see <samp>--disable-libvtv</samp> to turn off building libvtv). 614 <samp>--disable-vtable-verify</samp> is the default. 615 </p> 616 </dd> 617 <dt><span><code>--disable-gcov</code></span></dt> 618 <dd><p>Specify that the run-time library used for coverage analysis 619 and associated host tools should not be built. 620 </p> 621 </dd> 622 <dt><span><code>--disable-multilib</code></span></dt> 623 <dd><p>Specify that multiple target 624 libraries to support different target variants, calling 625 conventions, etc. should not be built. The default is to build a 626 predefined set of them. 627 </p> 628 <p>Some targets provide finer-grained control over which multilibs are built 629 (e.g., <samp>--disable-softfloat</samp>): 630 </p><dl compact="compact"> 631 <dt><span><code>arm-*-*</code></span></dt> 632 <dd><p>fpu, 26bit, underscore, interwork, biendian, nofmult. 633 </p> 634 </dd> 635 <dt><span><code>m68*-*-*</code></span></dt> 636 <dd><p>softfloat, m68881, m68000, m68020. 637 </p> 638 </dd> 639 <dt><span><code>mips*-*-*</code></span></dt> 640 <dd><p>single-float, biendian, softfloat. 641 </p> 642 </dd> 643 <dt><span><code>msp430-*-*</code></span></dt> 644 <dd><p>no-exceptions 645 </p> 646 </dd> 647 <dt><span><code>powerpc*-*-*, rs6000*-*-*</code></span></dt> 648 <dd><p>aix64, pthread, softfloat, powercpu, powerpccpu, powerpcos, biendian, 649 sysv, aix. 650 </p> 651 </dd> 652 </dl> 653 654 </dd> 655 <dt><span><code>--with-multilib-list=<var>list</var></code></span></dt> 656 <dt><span><code>--without-multilib-list</code></span></dt> 657 <dd><p>Specify what multilibs to build. <var>list</var> is a comma separated list of 658 values, possibly consisting of a single value. Currently only implemented 659 for aarch64*-*-*, arm*-*-*, loongarch64-*-*, riscv*-*-*, sh*-*-* and 660 x86-64-*-linux*. The accepted values and meaning for each target is given 661 below. 662 </p> 663 <dl compact="compact"> 664 <dt><span><code>aarch64*-*-*</code></span></dt> 665 <dd><p><var>list</var> is a comma separated list of <code>ilp32</code>, and <code>lp64</code> 666 to enable ILP32 and LP64 run-time libraries, respectively. If 667 <var>list</var> is empty, then there will be no multilibs and only the 668 default run-time library will be built. If <var>list</var> is 669 <code>default</code> or –with-multilib-list= is not specified, then the 670 default set of libraries is selected based on the value of 671 <samp>--target</samp>. 672 </p> 673 </dd> 674 <dt><span><code>arm*-*-*</code></span></dt> 675 <dd><p><var>list</var> is a comma separated list of <code>aprofile</code> and 676 <code>rmprofile</code> to build multilibs for A or R and M architecture 677 profiles respectively. Note that, due to some limitation of the current 678 multilib framework, using the combined <code>aprofile,rmprofile</code> 679 multilibs selects in some cases a less optimal multilib than when using 680 the multilib profile for the architecture targetted. The special value 681 <code>default</code> is also accepted and is equivalent to omitting the 682 option, i.e., only the default run-time library will be enabled. 683 </p> 684 <p><var>list</var> may instead contain <code>@name</code>, to use the multilib 685 configuration Makefile fragment <samp>name</samp> in <samp>gcc/config/arm</samp> in 686 the source tree (it is part of the corresponding sources, after all). 687 It is recommended, but not required, that files used for this purpose to 688 be named starting with <samp>t-ml-</samp>, to make their intended purpose 689 self-evident, in line with GCC conventions. Such files enable custom, 690 user-chosen multilib lists to be configured. Whether multiple such 691 files can be used together depends on the contents of the supplied 692 files. See <samp>gcc/config/arm/t-multilib</samp> and its supplementary 693 <samp>gcc/config/arm/t-*profile</samp> files for an example of what such 694 Makefile fragments might look like for this version of GCC. The macros 695 expected to be defined in these fragments are not stable across GCC 696 releases, so make sure they define the <code>MULTILIB</code>-related macros 697 expected by the version of GCC you are building. 698 See “Target Makefile Fragments” in the internals manual. 699 </p> 700 <p>The table below gives the combination of ISAs, architectures, FPUs and 701 floating-point ABIs for which multilibs are built for each predefined 702 profile. The union of these options is considered when specifying both 703 <code>aprofile</code> and <code>rmprofile</code>. 704 </p> 705 <table> 706 <tr><td width="15%">Option</td><td width="28%">aprofile</td><td width="30%">rmprofile</td></tr> 707 <tr><td width="15%">ISAs</td><td width="28%"><code>-marm</code> and <code>-mthumb</code></td><td width="30%"><code>-mthumb</code></td></tr> 708 <tr><td width="15%">Architectures<br><br><br><br><br><br></td><td width="28%">default architecture<br> 709 <code>-march=armv7-a</code><br> 710 <code>-march=armv7ve</code><br> 711 <code>-march=armv8-a</code><br><br><br></td><td width="30%">default architecture<br> 712 <code>-march=armv6s-m</code><br> 713 <code>-march=armv7-m</code><br> 714 <code>-march=armv7e-m</code><br> 715 <code>-march=armv8-m.base</code><br> 716 <code>-march=armv8-m.main</code><br> 717 <code>-march=armv7</code></td></tr> 718 <tr><td width="15%">FPUs<br><br><br><br><br></td><td width="28%">none<br> 719 <code>-mfpu=vfpv3-d16</code><br> 720 <code>-mfpu=neon</code><br> 721 <code>-mfpu=vfpv4-d16</code><br> 722 <code>-mfpu=neon-vfpv4</code><br> 723 <code>-mfpu=neon-fp-armv8</code></td><td width="30%">none<br> 724 <code>-mfpu=vfpv3-d16</code><br> 725 <code>-mfpu=fpv4-sp-d16</code><br> 726 <code>-mfpu=fpv5-sp-d16</code><br> 727 <code>-mfpu=fpv5-d16</code><br></td></tr> 728 <tr><td width="15%">floating-point ABIs<br><br></td><td width="28%"><code>-mfloat-abi=soft</code><br> 729 <code>-mfloat-abi=softfp</code><br> 730 <code>-mfloat-abi=hard</code></td><td width="30%"><code>-mfloat-abi=soft</code><br> 731 <code>-mfloat-abi=softfp</code><br> 732 <code>-mfloat-abi=hard</code></td></tr> 733 </table> 734 735 </dd> 736 <dt><span><code>loongarch*-*-*</code></span></dt> 737 <dd><p><var>list</var> is a comma-separated list of the following ABI identifiers: 738 <code>lp64d[/base]</code> <code>lp64f[/base]</code> <code>lp64d[/base]</code>, where the 739 <code>/base</code> suffix may be omitted, to enable their respective run-time 740 libraries. If <var>list</var> is empty or <code>default</code>, 741 or if <samp>--with-multilib-list</samp> is not specified, then the default ABI 742 as specified by <samp>--with-abi</samp> or implied by <samp>--target</samp> is selected. 743 </p> 744 </dd> 745 <dt><span><code>riscv*-*-*</code></span></dt> 746 <dd><p><var>list</var> is a single ABI name. The target architecture must be either 747 <code>rv32gc</code> or <code>rv64gc</code>. This will build a single multilib for the 748 specified architecture and ABI pair. If <code>--with-multilib-list</code> is not 749 given, then a default set of multilibs is selected based on the value of 750 <samp>--target</samp>. This is usually a large set of multilibs. 751 </p> 752 </dd> 753 <dt><span><code>sh*-*-*</code></span></dt> 754 <dd><p><var>list</var> is a comma separated list of CPU names. These must be of the 755 form <code>sh*</code> or <code>m*</code> (in which case they match the compiler option 756 for that processor). The list should not contain any endian options - 757 these are handled by <samp>--with-endian</samp>. 758 </p> 759 <p>If <var>list</var> is empty, then there will be no multilibs for extra 760 processors. The multilib for the secondary endian remains enabled. 761 </p> 762 <p>As a special case, if an entry in the list starts with a <code>!</code> 763 (exclamation point), then it is added to the list of excluded multilibs. 764 Entries of this sort should be compatible with ‘<samp>MULTILIB_EXCLUDES</samp>’ 765 (once the leading <code>!</code> has been stripped). 766 </p> 767 <p>If <samp>--with-multilib-list</samp> is not given, then a default set of 768 multilibs is selected based on the value of <samp>--target</samp>. This is 769 usually the complete set of libraries, but some targets imply a more 770 specialized subset. 771 </p> 772 <p>Example 1: to configure a compiler for SH4A only, but supporting both 773 endians, with little endian being the default: 774 </p><div class="example"> 775 <pre class="example">--with-cpu=sh4a --with-endian=little,big --with-multilib-list= 776 </pre></div> 777 778 <p>Example 2: to configure a compiler for both SH4A and SH4AL-DSP, but with 779 only little endian SH4AL: 780 </p><div class="example"> 781 <pre class="example">--with-cpu=sh4a --with-endian=little,big \ 782 --with-multilib-list=sh4al,!mb/m4al 783 </pre></div> 784 785 </dd> 786 <dt><span><code>x86-64-*-linux*</code></span></dt> 787 <dd><p><var>list</var> is a comma separated list of <code>m32</code>, <code>m64</code> and 788 <code>mx32</code> to enable 32-bit, 64-bit and x32 run-time libraries, 789 respectively. If <var>list</var> is empty, then there will be no multilibs 790 and only the default run-time library will be enabled. 791 </p> 792 <p>If <samp>--with-multilib-list</samp> is not given, then only 32-bit and 793 64-bit run-time libraries will be enabled. 794 </p></dd> 795 </dl> 796 797 </dd> 798 <dt><span><code>--with-multilib-generator=<var>config</var></code></span></dt> 799 <dd><p>Specify what multilibs to build. <var>config</var> is a semicolon separated list of 800 values, possibly consisting of a single value. Currently only implemented 801 for riscv*-*-elf*. The accepted values and meanings are given below. 802 </p> 803 804 <p>Every config is constructed with four components: architecture string, ABI, 805 reuse rule with architecture string and reuse rule with sub-extension. 806 </p> 807 <p>Example 1: Add multi-lib suppport for rv32i with ilp32. 808 </p><div class="example"> 809 <pre class="example">rv32i-ilp32-- 810 </pre></div> 811 812 <p>Example 2: Add multi-lib suppport for rv32i with ilp32 and rv32imafd with ilp32. 813 </p><div class="example"> 814 <pre class="example">rv32i-ilp32--;rv32imafd-ilp32-- 815 </pre></div> 816 817 <p>Example 3: Add multi-lib suppport for rv32i with ilp32; rv32im with ilp32 and 818 rv32ic with ilp32 will reuse this multi-lib set. 819 </p><div class="example"> 820 <pre class="example">rv32i-ilp32-rv32im-c 821 </pre></div> 822 823 <p>Example 4: Add multi-lib suppport for rv64ima with lp64; rv64imaf with lp64, 824 rv64imac with lp64 and rv64imafc with lp64 will reuse this multi-lib set. 825 </p><div class="example"> 826 <pre class="example">rv64ima-lp64--f,c,fc 827 </pre></div> 828 829 <p><samp>--with-multilib-generator</samp> have an optional configuration argument 830 <samp>--cmodel=val</samp> for code model, this option will expand with other 831 config options, <var>val</var> is a comma separated list of possible code model, 832 currently we support medlow and medany. 833 </p> 834 <p>Example 5: Add multi-lib suppport for rv64ima with lp64; rv64ima with lp64 and 835 medlow code model 836 </p><div class="example"> 837 <pre class="example">rv64ima-lp64--;--cmodel=medlow 838 </pre></div> 839 840 <p>Example 6: Add multi-lib suppport for rv64ima with lp64; rv64ima with lp64 and 841 medlow code model; rv64ima with lp64 and medany code model 842 </p><div class="example"> 843 <pre class="example">rv64ima-lp64--;--cmodel=medlow,medany 844 </pre></div> 845 846 </dd> 847 <dt><span><code>--with-endian=<var>endians</var></code></span></dt> 848 <dd><p>Specify what endians to use. 849 Currently only implemented for sh*-*-*. 850 </p> 851 <p><var>endians</var> may be one of the following: 852 </p><dl compact="compact"> 853 <dt><span><code>big</code></span></dt> 854 <dd><p>Use big endian exclusively. 855 </p></dd> 856 <dt><span><code>little</code></span></dt> 857 <dd><p>Use little endian exclusively. 858 </p></dd> 859 <dt><span><code>big,little</code></span></dt> 860 <dd><p>Use big endian by default. Provide a multilib for little endian. 861 </p></dd> 862 <dt><span><code>little,big</code></span></dt> 863 <dd><p>Use little endian by default. Provide a multilib for big endian. 864 </p></dd> 865 </dl> 866 867 </dd> 868 <dt><span><code>--enable-threads</code></span></dt> 869 <dd><p>Specify that the target 870 supports threads. This affects the Objective-C compiler and runtime 871 library, and exception handling for other languages like C++. 872 On some systems, this is the default. 873 </p> 874 <p>In general, the best (and, in many cases, the only known) threading 875 model available will be configured for use. Beware that on some 876 systems, GCC has not been taught what threading models are generally 877 available for the system. In this case, <samp>--enable-threads</samp> is an 878 alias for <samp>--enable-threads=single</samp>. 879 </p> 880 </dd> 881 <dt><span><code>--disable-threads</code></span></dt> 882 <dd><p>Specify that threading support should be disabled for the system. 883 This is an alias for <samp>--enable-threads=single</samp>. 884 </p> 885 </dd> 886 <dt><span><code>--enable-threads=<var>lib</var></code></span></dt> 887 <dd><p>Specify that 888 <var>lib</var> is the thread support library. This affects the Objective-C 889 compiler and runtime library, and exception handling for other languages 890 like C++. The possibilities for <var>lib</var> are: 891 </p> 892 <dl compact="compact"> 893 <dt><span><code>aix</code></span></dt> 894 <dd><p>AIX thread support. 895 </p></dd> 896 <dt><span><code>dce</code></span></dt> 897 <dd><p>DCE thread support. 898 </p></dd> 899 <dt><span><code>lynx</code></span></dt> 900 <dd><p>LynxOS thread support. 901 </p></dd> 902 <dt><span><code>mipssde</code></span></dt> 903 <dd><p>MIPS SDE thread support. 904 </p></dd> 905 <dt><span><code>no</code></span></dt> 906 <dd><p>This is an alias for ‘<samp>single</samp>’. 907 </p></dd> 908 <dt><span><code>posix</code></span></dt> 909 <dd><p>Generic POSIX/Unix98 thread support. 910 </p></dd> 911 <dt><span><code>rtems</code></span></dt> 912 <dd><p>RTEMS thread support. 913 </p></dd> 914 <dt><span><code>single</code></span></dt> 915 <dd><p>Disable thread support, should work for all platforms. 916 </p></dd> 917 <dt><span><code>tpf</code></span></dt> 918 <dd><p>TPF thread support. 919 </p></dd> 920 <dt><span><code>vxworks</code></span></dt> 921 <dd><p>VxWorks thread support. 922 </p></dd> 923 <dt><span><code>win32</code></span></dt> 924 <dd><p>Microsoft Win32 API thread support. 925 </p></dd> 926 </dl> 927 928 </dd> 929 <dt><span><code>--enable-tls</code></span></dt> 930 <dd><p>Specify that the target supports TLS (Thread Local Storage). Usually 931 configure can correctly determine if TLS is supported. In cases where 932 it guesses incorrectly, TLS can be explicitly enabled or disabled with 933 <samp>--enable-tls</samp> or <samp>--disable-tls</samp>. This can happen if 934 the assembler supports TLS but the C library does not, or if the 935 assumptions made by the configure test are incorrect. 936 </p> 937 </dd> 938 <dt><span><code>--disable-tls</code></span></dt> 939 <dd><p>Specify that the target does not support TLS. 940 This is an alias for <samp>--enable-tls=no</samp>. 941 </p> 942 </dd> 943 <dt><span><code>--disable-tm-clone-registry</code></span></dt> 944 <dd><p>Disable TM clone registry in libgcc. It is enabled in libgcc by default. 945 This option helps to reduce code size for embedded targets which do 946 not use transactional memory. 947 </p> 948 </dd> 949 <dt><span><code>--with-cpu=<var>cpu</var></code></span></dt> 950 <dt><span><code>--with-cpu-32=<var>cpu</var></code></span></dt> 951 <dt><span><code>--with-cpu-64=<var>cpu</var></code></span></dt> 952 <dd><p>Specify which cpu variant the compiler should generate code for by default. 953 <var>cpu</var> will be used as the default value of the <samp>-mcpu=</samp> switch. 954 This option is only supported on some targets, including ARC, ARM, i386, M68k, 955 PowerPC, and SPARC. It is mandatory for ARC. The <samp>--with-cpu-32</samp> and 956 <samp>--with-cpu-64</samp> options specify separate default CPUs for 957 32-bit and 64-bit modes; these options are only supported for aarch64, i386, 958 x86-64, PowerPC, and SPARC. 959 </p> 960 </dd> 961 <dt><span><code>--with-schedule=<var>cpu</var></code></span></dt> 962 <dt><span><code>--with-arch=<var>cpu</var></code></span></dt> 963 <dt><span><code>--with-arch-32=<var>cpu</var></code></span></dt> 964 <dt><span><code>--with-arch-64=<var>cpu</var></code></span></dt> 965 <dt><span><code>--with-tune=<var>cpu</var></code></span></dt> 966 <dt><span><code>--with-tune-32=<var>cpu</var></code></span></dt> 967 <dt><span><code>--with-tune-64=<var>cpu</var></code></span></dt> 968 <dt><span><code>--with-abi=<var>abi</var></code></span></dt> 969 <dt><span><code>--with-fpu=<var>type</var></code></span></dt> 970 <dt><span><code>--with-float=<var>type</var></code></span></dt> 971 <dd><p>These configure options provide default values for the <samp>-mschedule=</samp>, 972 <samp>-march=</samp>, <samp>-mtune=</samp>, <samp>-mabi=</samp>, and <samp>-mfpu=</samp> 973 options and for <samp>-mhard-float</samp> or <samp>-msoft-float</samp>. As with 974 <samp>--with-cpu</samp>, which switches will be accepted and acceptable values 975 of the arguments depend on the target. 976 </p> 977 </dd> 978 <dt><span><code>--with-mode=<var>mode</var></code></span></dt> 979 <dd><p>Specify if the compiler should default to <samp>-marm</samp> or <samp>-mthumb</samp>. 980 This option is only supported on ARM targets. 981 </p> 982 </dd> 983 <dt><span><code>--with-stack-offset=<var>num</var></code></span></dt> 984 <dd><p>This option sets the default for the -mstack-offset=<var>num</var> option, 985 and will thus generally also control the setting of this option for 986 libraries. This option is only supported on Epiphany targets. 987 </p> 988 </dd> 989 <dt><span><code>--with-fpmath=<var>isa</var></code></span></dt> 990 <dd><p>This options sets <samp>-mfpmath=sse</samp> by default and specifies the default 991 ISA for floating-point arithmetics. You can select either ‘<samp>sse</samp>’ which 992 enables <samp>-msse2</samp> or ‘<samp>avx</samp>’ which enables <samp>-mavx</samp> by default. 993 This option is only supported on i386 and x86-64 targets. 994 </p> 995 </dd> 996 <dt><span><code>--with-fp-32=<var>mode</var></code></span></dt> 997 <dd><p>On MIPS targets, set the default value for the <samp>-mfp</samp> option when using 998 the o32 ABI. The possibilities for <var>mode</var> are: 999 </p><dl compact="compact"> 1000 <dt><span><code>32</code></span></dt> 1001 <dd><p>Use the o32 FP32 ABI extension, as with the <samp>-mfp32</samp> command-line 1002 option. 1003 </p></dd> 1004 <dt><span><code>xx</code></span></dt> 1005 <dd><p>Use the o32 FPXX ABI extension, as with the <samp>-mfpxx</samp> command-line 1006 option. 1007 </p></dd> 1008 <dt><span><code>64</code></span></dt> 1009 <dd><p>Use the o32 FP64 ABI extension, as with the <samp>-mfp64</samp> command-line 1010 option. 1011 </p></dd> 1012 </dl> 1013 <p>In the absence of this configuration option the default is to use the o32 1014 FP32 ABI extension. 1015 </p> 1016 </dd> 1017 <dt><span><code>--with-odd-spreg-32</code></span></dt> 1018 <dd><p>On MIPS targets, set the <samp>-modd-spreg</samp> option by default when using 1019 the o32 ABI. 1020 </p> 1021 </dd> 1022 <dt><span><code>--without-odd-spreg-32</code></span></dt> 1023 <dd><p>On MIPS targets, set the <samp>-mno-odd-spreg</samp> option by default when using 1024 the o32 ABI. This is normally used in conjunction with 1025 <samp>--with-fp-32=64</samp> in order to target the o32 FP64A ABI extension. 1026 </p> 1027 </dd> 1028 <dt><span><code>--with-nan=<var>encoding</var></code></span></dt> 1029 <dd><p>On MIPS targets, set the default encoding convention to use for the 1030 special not-a-number (NaN) IEEE 754 floating-point data. The 1031 possibilities for <var>encoding</var> are: 1032 </p><dl compact="compact"> 1033 <dt><span><code>legacy</code></span></dt> 1034 <dd><p>Use the legacy encoding, as with the <samp>-mnan=legacy</samp> command-line 1035 option. 1036 </p></dd> 1037 <dt><span><code>2008</code></span></dt> 1038 <dd><p>Use the 754-2008 encoding, as with the <samp>-mnan=2008</samp> command-line 1039 option. 1040 </p></dd> 1041 </dl> 1042 <p>To use this configuration option you must have an assembler version 1043 installed that supports the <samp>-mnan=</samp> command-line option too. 1044 In the absence of this configuration option the default convention is 1045 the legacy encoding, as when neither of the <samp>-mnan=2008</samp> and 1046 <samp>-mnan=legacy</samp> command-line options has been used. 1047 </p> 1048 </dd> 1049 <dt><span><code>--with-divide=<var>type</var></code></span></dt> 1050 <dd><p>Specify how the compiler should generate code for checking for 1051 division by zero. This option is only supported on the MIPS target. 1052 The possibilities for <var>type</var> are: 1053 </p><dl compact="compact"> 1054 <dt><span><code>traps</code></span></dt> 1055 <dd><p>Division by zero checks use conditional traps (this is the default on 1056 systems that support conditional traps). 1057 </p></dd> 1058 <dt><span><code>breaks</code></span></dt> 1059 <dd><p>Division by zero checks use the break instruction. 1060 </p></dd> 1061 </dl> 1062 1063 1064 </dd> 1065 <dt><span><code>--with-llsc</code></span></dt> 1066 <dd><p>On MIPS targets, make <samp>-mllsc</samp> the default when no 1067 <samp>-mno-llsc</samp> option is passed. This is the default for 1068 Linux-based targets, as the kernel will emulate them if the ISA does 1069 not provide them. 1070 </p> 1071 </dd> 1072 <dt><span><code>--without-llsc</code></span></dt> 1073 <dd><p>On MIPS targets, make <samp>-mno-llsc</samp> the default when no 1074 <samp>-mllsc</samp> option is passed. 1075 </p> 1076 </dd> 1077 <dt><span><code>--with-synci</code></span></dt> 1078 <dd><p>On MIPS targets, make <samp>-msynci</samp> the default when no 1079 <samp>-mno-synci</samp> option is passed. 1080 </p> 1081 </dd> 1082 <dt><span><code>--without-synci</code></span></dt> 1083 <dd><p>On MIPS targets, make <samp>-mno-synci</samp> the default when no 1084 <samp>-msynci</samp> option is passed. This is the default. 1085 </p> 1086 </dd> 1087 <dt><span><code>--with-lxc1-sxc1</code></span></dt> 1088 <dd><p>On MIPS targets, make <samp>-mlxc1-sxc1</samp> the default when no 1089 <samp>-mno-lxc1-sxc1</samp> option is passed. This is the default. 1090 </p> 1091 </dd> 1092 <dt><span><code>--without-lxc1-sxc1</code></span></dt> 1093 <dd><p>On MIPS targets, make <samp>-mno-lxc1-sxc1</samp> the default when no 1094 <samp>-mlxc1-sxc1</samp> option is passed. The indexed load/store 1095 instructions are not directly a problem but can lead to unexpected 1096 behaviour when deployed in an application intended for a 32-bit address 1097 space but run on a 64-bit processor. The issue is seen because all 1098 known MIPS 64-bit Linux kernels execute o32 and n32 applications 1099 with 64-bit addressing enabled which affects the overflow behaviour 1100 of the indexed addressing mode. GCC will assume that ordinary 1101 32-bit arithmetic overflow behaviour is the same whether performed 1102 as an <code>addu</code> instruction or as part of the address calculation 1103 in <code>lwxc1</code> type instructions. This assumption holds true in a 1104 pure 32-bit environment and can hold true in a 64-bit environment if 1105 the address space is accurately set to be 32-bit for o32 and n32. 1106 </p> 1107 </dd> 1108 <dt><span><code>--with-madd4</code></span></dt> 1109 <dd><p>On MIPS targets, make <samp>-mmadd4</samp> the default when no 1110 <samp>-mno-madd4</samp> option is passed. This is the default. 1111 </p> 1112 </dd> 1113 <dt><span><code>--without-madd4</code></span></dt> 1114 <dd><p>On MIPS targets, make <samp>-mno-madd4</samp> the default when no 1115 <samp>-mmadd4</samp> option is passed. The <code>madd4</code> instruction 1116 family can be problematic when targeting a combination of cores that 1117 implement these instructions differently. There are two known cores 1118 that implement these as fused operations instead of unfused (where 1119 unfused is normally expected). Disabling these instructions is the 1120 only way to ensure compatible code is generated; this will incur 1121 a performance penalty. 1122 </p> 1123 </dd> 1124 <dt><span><code>--with-mips-plt</code></span></dt> 1125 <dd><p>On MIPS targets, make use of copy relocations and PLTs. 1126 These features are extensions to the traditional 1127 SVR4-based MIPS ABIs and require support from GNU binutils 1128 and the runtime C library. 1129 </p> 1130 </dd> 1131 <dt><span><code>--with-stack-clash-protection-guard-size=<var>size</var></code></span></dt> 1132 <dd><p>On certain targets this option sets the default stack clash protection guard 1133 size as a power of two in bytes. On AArch64 <var>size</var> is required to be either 1134 12 (4KB) or 16 (64KB). 1135 </p> 1136 </dd> 1137 <dt><span><code>--with-isa-spec=<var>ISA-spec-string</var></code></span></dt> 1138 <dd><p>On RISC-V targets specify the default version of the RISC-V Unprivileged 1139 (formerly User-Level) ISA specification to produce code conforming to. 1140 The possibilities for <var>ISA-spec-string</var> are: 1141 </p><dl compact="compact"> 1142 <dt><span><code>2.2</code></span></dt> 1143 <dd><p>Produce code conforming to version 2.2. 1144 </p></dd> 1145 <dt><span><code>20190608</code></span></dt> 1146 <dd><p>Produce code conforming to version 20190608. 1147 </p></dd> 1148 <dt><span><code>20191213</code></span></dt> 1149 <dd><p>Produce code conforming to version 20191213. 1150 </p></dd> 1151 </dl> 1152 <p>In the absence of this configuration option the default version is 20191213. 1153 </p> 1154 </dd> 1155 <dt><span><code>--enable-__cxa_atexit</code></span></dt> 1156 <dd><p>Define if you want to use __cxa_atexit, rather than atexit, to 1157 register C++ destructors for local statics and global objects. 1158 This is essential for fully standards-compliant handling of 1159 destructors, but requires __cxa_atexit in libc. This option is currently 1160 only available on systems with GNU libc. When enabled, this will cause 1161 <samp>-fuse-cxa-atexit</samp> to be passed by default. 1162 </p> 1163 </dd> 1164 <dt><span><code>--enable-gnu-indirect-function</code></span></dt> 1165 <dd><p>Define if you want to enable the <code>ifunc</code> attribute. This option is 1166 currently only available on systems with GNU libc on certain targets. 1167 </p> 1168 </dd> 1169 <dt><span><code>--enable-target-optspace</code></span></dt> 1170 <dd><p>Specify that target 1171 libraries should be optimized for code space instead of code speed. 1172 This is the default for the m32r platform. 1173 </p> 1174 </dd> 1175 <dt><span><code>--with-cpp-install-dir=<var>dirname</var></code></span></dt> 1176 <dd><p>Specify that the user visible <code>cpp</code> program should be installed 1177 in <samp><var>prefix</var>/<var>dirname</var>/cpp</samp>, in addition to <var>bindir</var>. 1178 </p> 1179 </dd> 1180 <dt><span><code>--enable-comdat</code></span></dt> 1181 <dd><p>Enable COMDAT group support. This is primarily used to override the 1182 automatically detected value. 1183 </p> 1184 </dd> 1185 <dt><span><code>--enable-initfini-array</code></span></dt> 1186 <dd><p>Force the use of sections <code>.init_array</code> and <code>.fini_array</code> 1187 (instead of <code>.init</code> and <code>.fini</code>) for constructors and 1188 destructors. Option <samp>--disable-initfini-array</samp> has the 1189 opposite effect. If neither option is specified, the configure script 1190 will try to guess whether the <code>.init_array</code> and 1191 <code>.fini_array</code> sections are supported and, if they are, use them. 1192 </p> 1193 </dd> 1194 <dt><span><code>--enable-link-mutex</code></span></dt> 1195 <dd><p>When building GCC, use a mutex to avoid linking the compilers for 1196 multiple languages at the same time, to avoid thrashing on build 1197 systems with limited free memory. The default is not to use such a mutex. 1198 </p> 1199 </dd> 1200 <dt><span><code>--enable-link-serialization</code></span></dt> 1201 <dd><p>When building GCC, use make dependencies to serialize linking the compilers for 1202 multiple languages, to avoid thrashing on build 1203 systems with limited free memory. The default is not to add such 1204 dependencies and thus with parallel make potentially link different 1205 compilers concurrently. If the argument is a positive integer, allow 1206 that number of concurrent link processes for the large binaries. 1207 </p> 1208 </dd> 1209 <dt><span><code>--enable-maintainer-mode</code></span></dt> 1210 <dd><p>The build rules that regenerate the Autoconf and Automake output files as 1211 well as the GCC master message catalog <samp>gcc.pot</samp> are normally 1212 disabled. This is because it can only be rebuilt if the complete source 1213 tree is present. If you have changed the sources and want to rebuild the 1214 catalog, configuring with <samp>--enable-maintainer-mode</samp> will enable 1215 this. Note that you need a recent version of the <code>gettext</code> tools 1216 to do so. 1217 </p> 1218 </dd> 1219 <dt><span><code>--disable-bootstrap</code></span></dt> 1220 <dd><p>For a native build, the default configuration is to perform 1221 a 3-stage bootstrap of the compiler when ‘<samp>make</samp>’ is invoked, 1222 testing that GCC can compile itself correctly. If you want to disable 1223 this process, you can configure with <samp>--disable-bootstrap</samp>. 1224 </p> 1225 </dd> 1226 <dt><span><code>--enable-bootstrap</code></span></dt> 1227 <dd><p>In special cases, you may want to perform a 3-stage build 1228 even if the target and host triplets are different. 1229 This is possible when the host can run code compiled for 1230 the target (e.g. host is i686-linux, target is i486-linux). 1231 Starting from GCC 4.2, to do this you have to configure explicitly 1232 with <samp>--enable-bootstrap</samp>. 1233 </p> 1234 </dd> 1235 <dt><span><code>--enable-generated-files-in-srcdir</code></span></dt> 1236 <dd><p>Neither the .c and .h files that are generated from Bison and flex nor the 1237 info manuals and man pages that are built from the .texi files are present 1238 in the repository development tree. When building GCC from that development tree, 1239 or from one of our snapshots, those generated files are placed in your 1240 build directory, which allows for the source to be in a readonly 1241 directory. 1242 </p> 1243 <p>If you configure with <samp>--enable-generated-files-in-srcdir</samp> then those 1244 generated files will go into the source directory. This is mainly intended 1245 for generating release or prerelease tarballs of the GCC sources, since it 1246 is not a requirement that the users of source releases to have flex, Bison, 1247 or makeinfo. 1248 </p> 1249 </dd> 1250 <dt><span><code>--enable-version-specific-runtime-libs</code></span></dt> 1251 <dd><p>Specify 1252 that runtime libraries should be installed in the compiler specific 1253 subdirectory (<samp><var>libdir</var>/gcc</samp>) rather than the usual places. In 1254 addition, ‘<samp>libstdc++</samp>’’s include files will be installed into 1255 <samp><var>libdir</var></samp> unless you overruled it by using 1256 <samp>--with-gxx-include-dir=<var>dirname</var></samp>. Using this option is 1257 particularly useful if you intend to use several versions of GCC in 1258 parallel. The default is ‘<samp>yes</samp>’ for ‘<samp>libada</samp>’, and ‘<samp>no</samp>’ for 1259 the remaining libraries. 1260 </p> 1261 </dd> 1262 <dt><span><code><span id="WithAixSoname"></span>--with-aix-soname=‘<samp>aix</samp>’, ‘<samp>svr4</samp>’ or ‘<samp>both</samp>’</code></span></dt> 1263 <dd><p>Traditional AIX shared library versioning (versioned <code>Shared Object</code> 1264 files as members of unversioned <code>Archive Library</code> files named 1265 ‘<samp>lib.a</samp>’) causes numerous headaches for package managers. However, 1266 <code>Import Files</code> as members of <code>Archive Library</code> files allow for 1267 <strong>filename-based versioning</strong> of shared libraries as seen on Linux/SVR4, 1268 where this is called the "SONAME". But as they prevent static linking, 1269 <code>Import Files</code> may be used with <code>Runtime Linking</code> only, where the 1270 linker does search for ‘<samp>libNAME.so</samp>’ before ‘<samp>libNAME.a</samp>’ library 1271 filenames with the ‘<samp>-lNAME</samp>’ linker flag. 1272 </p> 1273 <span id="AixLdCommand"></span><p>For detailed information please refer to the AIX 1274 <a href="https://www.ibm.com/support/knowledgecenter/search/%22the%20ld%20command%2C%20also%20called%20the%20linkage%20editor%20or%20binder%22">ld 1275 Command</a> reference. 1276 </p> 1277 <p>As long as shared library creation is enabled, upon: 1278 </p><dl compact="compact"> 1279 <dt><span><code>--with-aix-soname=aix</code></span></dt> 1280 <dt><span><code>--with-aix-soname=both</code></span></dt> 1281 <dd><p>A (traditional AIX) <code>Shared Archive Library</code> file is created: 1282 </p><ul> 1283 <li> using the ‘<samp>libNAME.a</samp>’ filename scheme 1284 </li><li> with the <code>Shared Object</code> file as archive member named 1285 ‘<samp>libNAME.so.V</samp>’ (except for ‘<samp>libgcc_s</samp>’, where the <code>Shared 1286 Object</code> file is named ‘<samp>shr.o</samp>’ for backwards compatibility), which 1287 <ul class="no-bullet"> 1288 <li>- is used for runtime loading from inside the ‘<samp>libNAME.a</samp>’ file 1289 </li><li>- is used for dynamic loading via 1290 <code>dlopen("libNAME.a(libNAME.so.V)", RTLD_MEMBER)</code> 1291 </li><li>- is used for shared linking 1292 </li><li>- is used for static linking, so no separate <code>Static Archive 1293 Library</code> file is needed 1294 </li></ul> 1295 </li></ul> 1296 </dd> 1297 <dt><span><code>--with-aix-soname=both</code></span></dt> 1298 <dt><span><code>--with-aix-soname=svr4</code></span></dt> 1299 <dd><p>A (second) <code>Shared Archive Library</code> file is created: 1300 </p><ul> 1301 <li> using the ‘<samp>libNAME.so.V</samp>’ filename scheme 1302 </li><li> with the <code>Shared Object</code> file as archive member named 1303 ‘<samp>shr.o</samp>’, which 1304 <ul class="no-bullet"> 1305 <li>- is created with the <code>-G linker flag</code> 1306 </li><li>- has the <code>F_LOADONLY</code> flag set 1307 </li><li>- is used for runtime loading from inside the ‘<samp>libNAME.so.V</samp>’ file 1308 </li><li>- is used for dynamic loading via <code>dlopen("libNAME.so.V(shr.o)", 1309 RTLD_MEMBER)</code> 1310 </li></ul> 1311 </li><li> with the <code>Import File</code> as archive member named ‘<samp>shr.imp</samp>’, 1312 which 1313 <ul class="no-bullet"> 1314 <li>- refers to ‘<samp>libNAME.so.V(shr.o)</samp>’ as the "SONAME", to be recorded 1315 in the <code>Loader Section</code> of subsequent binaries 1316 </li><li>- indicates whether ‘<samp>libNAME.so.V(shr.o)</samp>’ is 32 or 64 bit 1317 </li><li>- lists all the public symbols exported by ‘<samp>lib.so.V(shr.o)</samp>’, 1318 eventually decorated with the <code>‘<samp>weak</samp>’ Keyword</code> 1319 </li><li>- is necessary for shared linking against ‘<samp>lib.so.V(shr.o)</samp>’ 1320 </li></ul> 1321 </li></ul> 1322 <p>A symbolic link using the ‘<samp>libNAME.so</samp>’ filename scheme is created: 1323 </p><ul> 1324 <li> pointing to the ‘<samp>libNAME.so.V</samp>’ <code>Shared Archive Library</code> file 1325 </li><li> to permit the <code>ld Command</code> to find ‘<samp>lib.so.V(shr.imp)</samp>’ via 1326 the ‘<samp>-lNAME</samp>’ argument (requires <code>Runtime Linking</code> to be enabled) 1327 </li><li> to permit dynamic loading of ‘<samp>lib.so.V(shr.o)</samp>’ without the need 1328 to specify the version number via <code>dlopen("libNAME.so(shr.o)", 1329 RTLD_MEMBER)</code> 1330 </li></ul> 1331 </dd> 1332 </dl> 1333 1334 <p>As long as static library creation is enabled, upon: 1335 </p><dl compact="compact"> 1336 <dt><span><code>--with-aix-soname=svr4</code></span></dt> 1337 <dd><p>A <code>Static Archive Library</code> is created: 1338 </p><ul> 1339 <li> using the ‘<samp>libNAME.a</samp>’ filename scheme 1340 </li><li> with all the <code>Static Object</code> files as archive members, which 1341 <ul class="no-bullet"> 1342 <li>- are used for static linking 1343 </li></ul> 1344 </li></ul> 1345 </dd> 1346 </dl> 1347 1348 <p>While the aix-soname=‘<samp>svr4</samp>’ option does not create <code>Shared Object</code> 1349 files as members of unversioned <code>Archive Library</code> files any more, package 1350 managers still are responsible to 1351 <a href="./specific.html#TransferAixShobj">transfer</a> <code>Shared Object</code> files 1352 found as member of a previously installed unversioned <code>Archive Library</code> 1353 file into the newly installed <code>Archive Library</code> file with the same 1354 filename. 1355 </p> 1356 <p><em>WARNING:</em> Creating <code>Shared Object</code> files with <code>Runtime Linking</code> 1357 enabled may bloat the TOC, eventually leading to <code>TOC overflow</code> errors, 1358 requiring the use of either the <samp>-Wl,-bbigtoc</samp> linker flag (seen to 1359 break with the <code>GDB</code> debugger) or some of the TOC-related compiler flags, 1360 see “RS/6000 and PowerPC Options” in the main manual. 1361 </p> 1362 <p><samp>--with-aix-soname</samp> is currently supported by ‘<samp>libgcc_s</samp>’ only, so 1363 this option is still experimental and not for normal use yet. 1364 </p> 1365 <p>Default is the traditional behavior <samp>--with-aix-soname=‘<samp>aix</samp>’</samp>. 1366 </p> 1367 </dd> 1368 <dt><span><code>--enable-languages=<var>lang1</var>,<var>lang2</var>,…</code></span></dt> 1369 <dd><p>Specify that only a particular subset of compilers and 1370 their runtime libraries should be built. For a list of valid values for 1371 <var>langN</var> you can issue the following command in the 1372 <samp>gcc</samp> directory of your GCC source tree:<br> 1373 </p><div class="example"> 1374 <pre class="example">grep ^language= */config-lang.in 1375 </pre></div> 1376 <p>Currently, you can use any of the following: 1377 <code>all</code>, <code>default</code>, <code>ada</code>, <code>c</code>, <code>c++</code>, <code>d</code>, 1378 <code>fortran</code>, <code>go</code>, <code>jit</code>, <code>lto</code>, <code>objc</code>, <code>obj-c++</code>. 1379 Building the Ada compiler has special requirements, see below. 1380 If you do not pass this flag, or specify the option <code>default</code>, then the 1381 default languages available in the <samp>gcc</samp> sub-tree will be configured. 1382 Ada, D, Go, Jit, and Objective-C++ are not default languages. LTO is not a 1383 default language, but is built by default because <samp>--enable-lto</samp> is 1384 enabled by default. The other languages are default languages. If 1385 <code>all</code> is specified, then all available languages are built. An 1386 exception is <code>jit</code> language, which requires 1387 <samp>--enable-host-shared</samp> to be included with <code>all</code>. 1388 </p> 1389 </dd> 1390 <dt><span><code>--enable-stage1-languages=<var>lang1</var>,<var>lang2</var>,…</code></span></dt> 1391 <dd><p>Specify that a particular subset of compilers and their runtime 1392 libraries should be built with the system C compiler during stage 1 of 1393 the bootstrap process, rather than only in later stages with the 1394 bootstrapped C compiler. The list of valid values is the same as for 1395 <samp>--enable-languages</samp>, and the option <code>all</code> will select all 1396 of the languages enabled by <samp>--enable-languages</samp>. This option is 1397 primarily useful for GCC development; for instance, when a development 1398 version of the compiler cannot bootstrap due to compiler bugs, or when 1399 one is debugging front ends other than the C front end. When this 1400 option is used, one can then build the target libraries for the 1401 specified languages with the stage-1 compiler by using <code>make 1402 stage1-bubble all-target</code>, or run the testsuite on the stage-1 compiler 1403 for the specified languages using <code>make stage1-start check-gcc</code>. 1404 </p> 1405 </dd> 1406 <dt><span><code>--disable-libada</code></span></dt> 1407 <dd><p>Specify that the run-time libraries and tools used by GNAT should not 1408 be built. This can be useful for debugging, or for compatibility with 1409 previous Ada build procedures, when it was required to explicitly 1410 do a ‘<samp>make -C gcc gnatlib_and_tools</samp>’. 1411 </p> 1412 </dd> 1413 <dt><span><code>--disable-libsanitizer</code></span></dt> 1414 <dd><p>Specify that the run-time libraries for the various sanitizers should 1415 not be built. 1416 </p> 1417 </dd> 1418 <dt><span><code>--disable-libssp</code></span></dt> 1419 <dd><p>Specify that the run-time libraries for stack smashing protection 1420 should not be built or linked against. On many targets library support 1421 is provided by the C library instead. 1422 </p> 1423 </dd> 1424 <dt><span><code>--disable-libquadmath</code></span></dt> 1425 <dd><p>Specify that the GCC quad-precision math library should not be built. 1426 On some systems, the library is required to be linkable when building 1427 the Fortran front end, unless <samp>--disable-libquadmath-support</samp> 1428 is used. 1429 </p> 1430 </dd> 1431 <dt><span><code>--disable-libquadmath-support</code></span></dt> 1432 <dd><p>Specify that the Fortran front end and <code>libgfortran</code> do not add 1433 support for <code>libquadmath</code> on systems supporting it. 1434 </p> 1435 </dd> 1436 <dt><span><code>--disable-libgomp</code></span></dt> 1437 <dd><p>Specify that the GNU Offloading and Multi Processing Runtime Library 1438 should not be built. 1439 </p> 1440 </dd> 1441 <dt><span><code>--disable-libvtv</code></span></dt> 1442 <dd><p>Specify that the run-time libraries used by vtable verification 1443 should not be built. 1444 </p> 1445 </dd> 1446 <dt><span><code>--with-dwarf2</code></span></dt> 1447 <dd><p>Specify that the compiler should 1448 use DWARF 2 debugging information as the default. 1449 </p> 1450 </dd> 1451 <dt><span><code>--with-advance-toolchain=<var>at</var></code></span></dt> 1452 <dd><p>On 64-bit PowerPC Linux systems, configure the compiler to use the 1453 header files, library files, and the dynamic linker from the Advance 1454 Toolchain release <var>at</var> instead of the default versions that are 1455 provided by the Linux distribution. In general, this option is 1456 intended for the developers of GCC, and it is not intended for general 1457 use. 1458 </p> 1459 </dd> 1460 <dt><span><code>--enable-targets=all</code></span></dt> 1461 <dt><span><code>--enable-targets=<var>target_list</var></code></span></dt> 1462 <dd><p>Some GCC targets, e.g. powerpc64-linux, build bi-arch compilers. 1463 These are compilers that are able to generate either 64-bit or 32-bit 1464 code. Typically, the corresponding 32-bit target, e.g. 1465 powerpc-linux for powerpc64-linux, only generates 32-bit code. This 1466 option enables the 32-bit target to be a bi-arch compiler, which is 1467 useful when you want a bi-arch compiler that defaults to 32-bit, and 1468 you are building a bi-arch or multi-arch binutils in a combined tree. 1469 On mips-linux, this will build a tri-arch compiler (ABI o32/n32/64), 1470 defaulted to o32. 1471 Currently, this option only affects sparc-linux, powerpc-linux, x86-linux, 1472 mips-linux and s390-linux. 1473 </p> 1474 </dd> 1475 <dt><span><code>--enable-default-pie</code></span></dt> 1476 <dd><p>Turn on <samp>-fPIE</samp> and <samp>-pie</samp> by default. 1477 </p> 1478 </dd> 1479 <dt><span><code>--enable-secureplt</code></span></dt> 1480 <dd><p>This option enables <samp>-msecure-plt</samp> by default for powerpc-linux. 1481 See “RS/6000 and PowerPC Options” in the main manual 1482 </p> 1483 </dd> 1484 <dt><span><code>--enable-default-ssp</code></span></dt> 1485 <dd><p>Turn on <samp>-fstack-protector-strong</samp> by default. 1486 </p> 1487 </dd> 1488 <dt><span><code>--enable-cld</code></span></dt> 1489 <dd><p>This option enables <samp>-mcld</samp> by default for 32-bit x86 targets. 1490 See “i386 and x86-64 Options” in the main manual 1491 </p> 1492 </dd> 1493 <dt><span><code>--enable-large-address-aware</code></span></dt> 1494 <dd><p>The <samp>--enable-large-address-aware</samp> option arranges for MinGW 1495 executables to be linked using the <samp>--large-address-aware</samp> 1496 option, that enables the use of more than 2GB of memory. If GCC is 1497 configured with this option, its effects can be reversed by passing the 1498 <samp>-Wl,--disable-large-address-aware</samp> option to the so-configured 1499 compiler driver. 1500 </p> 1501 </dd> 1502 <dt><span><code>--enable-win32-registry</code></span></dt> 1503 <dt><span><code>--enable-win32-registry=<var>key</var></code></span></dt> 1504 <dt><span><code>--disable-win32-registry</code></span></dt> 1505 <dd><p>The <samp>--enable-win32-registry</samp> option enables Microsoft Windows-hosted GCC 1506 to look up installations paths in the registry using the following key: 1507 </p> 1508 <div class="example"> 1509 <pre class="example"><code>HKEY_LOCAL_MACHINE\SOFTWARE\Free Software Foundation\<var>key</var></code> 1510 </pre></div> 1511 1512 <p><var>key</var> defaults to GCC version number, and can be overridden by the 1513 <samp>--enable-win32-registry=<var>key</var></samp> option. Vendors and distributors 1514 who use custom installers are encouraged to provide a different key, 1515 perhaps one comprised of vendor name and GCC version number, to 1516 avoid conflict with existing installations. This feature is enabled 1517 by default, and can be disabled by <samp>--disable-win32-registry</samp> 1518 option. This option has no effect on the other hosts. 1519 </p> 1520 </dd> 1521 <dt><span><code>--nfp</code></span></dt> 1522 <dd><p>Specify that the machine does not have a floating point unit. This 1523 option only applies to ‘<samp>m68k-sun-sunos<var>n</var></samp>’. On any other 1524 system, <samp>--nfp</samp> has no effect. 1525 </p> 1526 </dd> 1527 <dt><span><code>--enable-werror</code></span></dt> 1528 <dt><span><code>--disable-werror</code></span></dt> 1529 <dt><span><code>--enable-werror=yes</code></span></dt> 1530 <dt><span><code>--enable-werror=no</code></span></dt> 1531 <dd><p>When you specify this option, it controls whether certain files in the 1532 compiler are built with <samp>-Werror</samp> in bootstrap stage2 and later. 1533 If you don’t specify it, <samp>-Werror</samp> is turned on for the main 1534 development trunk. However it defaults to off for release branches and 1535 final releases. The specific files which get <samp>-Werror</samp> are 1536 controlled by the Makefiles. 1537 </p> 1538 </dd> 1539 <dt><span><code>--enable-checking</code></span></dt> 1540 <dt><span><code>--disable-checking</code></span></dt> 1541 <dt><span><code>--enable-checking=<var>list</var></code></span></dt> 1542 <dd><p>This option controls performing internal consistency checks in the compiler. 1543 It does not change the generated code, but adds error checking of the 1544 requested complexity. This slows down the compiler and may only work 1545 properly if you are building the compiler with GCC. 1546 </p> 1547 <p>When the option is not specified, the active set of checks depends on context. 1548 Namely, bootstrap stage 1 defaults to ‘<samp>--enable-checking=yes</samp>’, builds 1549 from release branches or release archives default to 1550 ‘<samp>--enable-checking=release</samp>’, and otherwise 1551 ‘<samp>--enable-checking=yes,extra</samp>’ is used. When the option is 1552 specified without a <var>list</var>, the result is the same as 1553 ‘<samp>--enable-checking=yes</samp>’. Likewise, ‘<samp>--disable-checking</samp>’ is 1554 equivalent to ‘<samp>--enable-checking=no</samp>’. 1555 </p> 1556 <p>The categories of checks available in <var>list</var> are ‘<samp>yes</samp>’ (most common 1557 checks ‘<samp>assert,misc,gc,gimple,rtlflag,runtime,tree,types</samp>’), ‘<samp>no</samp>’ 1558 (no checks at all), ‘<samp>all</samp>’ (all but ‘<samp>valgrind</samp>’), ‘<samp>release</samp>’ 1559 (cheapest checks ‘<samp>assert,runtime</samp>’) or ‘<samp>none</samp>’ (same as ‘<samp>no</samp>’). 1560 ‘<samp>release</samp>’ checks are always on and to disable them 1561 ‘<samp>--disable-checking</samp>’ or ‘<samp>--enable-checking=no[,<other checks>]</samp>’ 1562 must be explicitly requested. Disabling assertions makes the compiler and 1563 runtime slightly faster but increases the risk of undetected internal errors 1564 causing wrong code to be generated. 1565 </p> 1566 <p>Individual checks can be enabled with these flags: ‘<samp>assert</samp>’, ‘<samp>df</samp>’, 1567 ‘<samp>extra</samp>’, ‘<samp>fold</samp>’, ‘<samp>gc</samp>’, ‘<samp>gcac</samp>’, ‘<samp>gimple</samp>’, 1568 ‘<samp>misc</samp>’, ‘<samp>rtl</samp>’, ‘<samp>rtlflag</samp>’, ‘<samp>runtime</samp>’, ‘<samp>tree</samp>’, 1569 ‘<samp>types</samp>’ and ‘<samp>valgrind</samp>’. ‘<samp>extra</samp>’ extends ‘<samp>misc</samp>’ 1570 checking with extra checks that might affect code generation and should 1571 therefore not differ between stage1 and later stages in bootstrap. 1572 </p> 1573 <p>The ‘<samp>valgrind</samp>’ check requires the external <code>valgrind</code> simulator, 1574 available from <a href="https://valgrind.org">https://valgrind.org</a>. The ‘<samp>rtl</samp>’ checks are 1575 expensive and the ‘<samp>df</samp>’, ‘<samp>gcac</samp>’ and ‘<samp>valgrind</samp>’ checks are very 1576 expensive. 1577 </p> 1578 </dd> 1579 <dt><span><code>--disable-stage1-checking</code></span></dt> 1580 <dt><span><code>--enable-stage1-checking</code></span></dt> 1581 <dt><span><code>--enable-stage1-checking=<var>list</var></code></span></dt> 1582 <dd><p>This option affects only bootstrap build. If no <samp>--enable-checking</samp> 1583 option is specified the stage1 compiler is built with ‘<samp>yes</samp>’ checking 1584 enabled, otherwise the stage1 checking flags are the same as specified by 1585 <samp>--enable-checking</samp>. To build the stage1 compiler with 1586 different checking options use <samp>--enable-stage1-checking</samp>. 1587 The list of checking options is the same as for <samp>--enable-checking</samp>. 1588 If your system is too slow or too small to bootstrap a released compiler 1589 with checking for stage1 enabled, you can use ‘<samp>--disable-stage1-checking</samp>’ 1590 to disable checking for the stage1 compiler. 1591 </p> 1592 </dd> 1593 <dt><span><code>--enable-coverage</code></span></dt> 1594 <dt><span><code>--enable-coverage=<var>level</var></code></span></dt> 1595 <dd><p>With this option, the compiler is built to collect self coverage 1596 information, every time it is run. This is for internal development 1597 purposes, and only works when the compiler is being built with gcc. The 1598 <var>level</var> argument controls whether the compiler is built optimized or 1599 not, values are ‘<samp>opt</samp>’ and ‘<samp>noopt</samp>’. For coverage analysis you 1600 want to disable optimization, for performance analysis you want to 1601 enable optimization. When coverage is enabled, the default level is 1602 without optimization. 1603 </p> 1604 </dd> 1605 <dt><span><code>--enable-gather-detailed-mem-stats</code></span></dt> 1606 <dd><p>When this option is specified more detailed information on memory 1607 allocation is gathered. This information is printed when using 1608 <samp>-fmem-report</samp>. 1609 </p> 1610 </dd> 1611 <dt><span><code>--enable-valgrind-annotations</code></span></dt> 1612 <dd><p>Mark selected memory related operations in the compiler when run under 1613 valgrind to suppress false positives. 1614 </p> 1615 </dd> 1616 <dt><span><code>--enable-nls</code></span></dt> 1617 <dt><span><code>--disable-nls</code></span></dt> 1618 <dd><p>The <samp>--enable-nls</samp> option enables Native Language Support (NLS), 1619 which lets GCC output diagnostics in languages other than American 1620 English. Native Language Support is enabled by default if not doing a 1621 canadian cross build. The <samp>--disable-nls</samp> option disables NLS. 1622 </p> 1623 </dd> 1624 <dt><span><code>--with-included-gettext</code></span></dt> 1625 <dd><p>If NLS is enabled, the <samp>--with-included-gettext</samp> option causes the build 1626 procedure to prefer its copy of GNU <code>gettext</code>. 1627 </p> 1628 </dd> 1629 <dt><span><code>--with-catgets</code></span></dt> 1630 <dd><p>If NLS is enabled, and if the host lacks <code>gettext</code> but has the 1631 inferior <code>catgets</code> interface, the GCC build procedure normally 1632 ignores <code>catgets</code> and instead uses GCC’s copy of the GNU 1633 <code>gettext</code> library. The <samp>--with-catgets</samp> option causes the 1634 build procedure to use the host’s <code>catgets</code> in this situation. 1635 </p> 1636 </dd> 1637 <dt><span><code>--with-libiconv-prefix=<var>dir</var></code></span></dt> 1638 <dd><p>Search for libiconv header files in <samp><var>dir</var>/include</samp> and 1639 libiconv library files in <samp><var>dir</var>/lib</samp>. 1640 </p> 1641 </dd> 1642 <dt><span><code>--enable-obsolete</code></span></dt> 1643 <dd><p>Enable configuration for an obsoleted system. If you attempt to 1644 configure GCC for a system (build, host, or target) which has been 1645 obsoleted, and you do not specify this flag, configure will halt with an 1646 error message. 1647 </p> 1648 <p>All support for systems which have been obsoleted in one release of GCC 1649 is removed entirely in the next major release, unless someone steps 1650 forward to maintain the port. 1651 </p> 1652 </dd> 1653 <dt><span><code>--enable-decimal-float</code></span></dt> 1654 <dt><span><code>--enable-decimal-float=yes</code></span></dt> 1655 <dt><span><code>--enable-decimal-float=no</code></span></dt> 1656 <dt><span><code>--enable-decimal-float=bid</code></span></dt> 1657 <dt><span><code>--enable-decimal-float=dpd</code></span></dt> 1658 <dt><span><code>--disable-decimal-float</code></span></dt> 1659 <dd><p>Enable (or disable) support for the C decimal floating point extension 1660 that is in the IEEE 754-2008 standard. This is enabled by default only 1661 on PowerPC, i386, and x86_64 GNU/Linux systems. Other systems may also 1662 support it, but require the user to specifically enable it. You can 1663 optionally control which decimal floating point format is used (either 1664 ‘<samp>bid</samp>’ or ‘<samp>dpd</samp>’). The ‘<samp>bid</samp>’ (binary integer decimal) 1665 format is default on i386 and x86_64 systems, and the ‘<samp>dpd</samp>’ 1666 (densely packed decimal) format is default on PowerPC systems. 1667 </p> 1668 </dd> 1669 <dt><span><code>--enable-fixed-point</code></span></dt> 1670 <dt><span><code>--disable-fixed-point</code></span></dt> 1671 <dd><p>Enable (or disable) support for C fixed-point arithmetic. 1672 This option is enabled by default for some targets (such as MIPS) which 1673 have hardware-support for fixed-point operations. On other targets, you 1674 may enable this option manually. 1675 </p> 1676 </dd> 1677 <dt><span><code>--with-long-double-128</code></span></dt> 1678 <dd><p>Specify if <code>long double</code> type should be 128-bit by default on selected 1679 GNU/Linux architectures. If using <code>--without-long-double-128</code>, 1680 <code>long double</code> will be by default 64-bit, the same as <code>double</code> type. 1681 When neither of these configure options are used, the default will be 1682 128-bit <code>long double</code> when built against GNU C Library 2.4 and later, 1683 64-bit <code>long double</code> otherwise. 1684 </p> 1685 </dd> 1686 <dt><span><code>--with-long-double-format=ibm</code></span></dt> 1687 <dt><span><code>--with-long-double-format=ieee</code></span></dt> 1688 <dd><p>Specify whether <code>long double</code> uses the IBM extended double format 1689 or the IEEE 128-bit floating point format on PowerPC Linux systems. 1690 This configuration switch will only work on little endian PowerPC 1691 Linux systems and on big endian 64-bit systems where the default cpu 1692 is at least power7 (i.e. <samp>--with-cpu=power7</samp>, 1693 <samp>--with-cpu=power8</samp>, or <samp>--with-cpu=power9</samp> is used). 1694 </p> 1695 <p>If you use the <samp>--with-long-double-64</samp> configuration option, 1696 the <samp>--with-long-double-format=ibm</samp> and 1697 <samp>--with-long-double-format=ieee</samp> options are ignored. 1698 </p> 1699 <p>The default <code>long double</code> format is to use IBM extended double. 1700 Until all of the libraries are converted to use IEEE 128-bit floating 1701 point, it is not recommended to use 1702 <samp>--with-long-double-format=ieee</samp>. 1703 </p> 1704 </dd> 1705 <dt><span><code>--enable-fdpic</code></span></dt> 1706 <dd><p>On SH Linux systems, generate ELF FDPIC code. 1707 </p> 1708 </dd> 1709 <dt><span><code>--with-gmp=<var>pathname</var></code></span></dt> 1710 <dt><span><code>--with-gmp-include=<var>pathname</var></code></span></dt> 1711 <dt><span><code>--with-gmp-lib=<var>pathname</var></code></span></dt> 1712 <dt><span><code>--with-mpfr=<var>pathname</var></code></span></dt> 1713 <dt><span><code>--with-mpfr-include=<var>pathname</var></code></span></dt> 1714 <dt><span><code>--with-mpfr-lib=<var>pathname</var></code></span></dt> 1715 <dt><span><code>--with-mpc=<var>pathname</var></code></span></dt> 1716 <dt><span><code>--with-mpc-include=<var>pathname</var></code></span></dt> 1717 <dt><span><code>--with-mpc-lib=<var>pathname</var></code></span></dt> 1718 <dd><p>If you want to build GCC but do not have the GMP library, the MPFR 1719 library and/or the MPC library installed in a standard location and 1720 do not have their sources present in the GCC source tree then you 1721 can explicitly specify the directory where they are installed 1722 (‘<samp>--with-gmp=<var>gmpinstalldir</var></samp>’, 1723 ‘<samp>--with-mpfr=<var>mpfrinstalldir</var></samp>’, 1724 ‘<samp>--with-mpc=<var>mpcinstalldir</var></samp>’). The 1725 <samp>--with-gmp=<var>gmpinstalldir</var></samp> option is shorthand for 1726 <samp>--with-gmp-lib=<var>gmpinstalldir</var>/lib</samp> and 1727 <samp>--with-gmp-include=<var>gmpinstalldir</var>/include</samp>. Likewise the 1728 <samp>--with-mpfr=<var>mpfrinstalldir</var></samp> option is shorthand for 1729 <samp>--with-mpfr-lib=<var>mpfrinstalldir</var>/lib</samp> and 1730 <samp>--with-mpfr-include=<var>mpfrinstalldir</var>/include</samp>, also the 1731 <samp>--with-mpc=<var>mpcinstalldir</var></samp> option is shorthand for 1732 <samp>--with-mpc-lib=<var>mpcinstalldir</var>/lib</samp> and 1733 <samp>--with-mpc-include=<var>mpcinstalldir</var>/include</samp>. If these 1734 shorthand assumptions are not correct, you can use the explicit 1735 include and lib options directly. You might also need to ensure the 1736 shared libraries can be found by the dynamic linker when building and 1737 using GCC, for example by setting the runtime shared library path 1738 variable (<code>LD_LIBRARY_PATH</code> on GNU/Linux and Solaris systems). 1739 </p> 1740 <p>These flags are applicable to the host platform only. When building 1741 a cross compiler, they will not be used to configure target libraries. 1742 </p> 1743 </dd> 1744 <dt><span><code>--with-isl=<var>pathname</var></code></span></dt> 1745 <dt><span><code>--with-isl-include=<var>pathname</var></code></span></dt> 1746 <dt><span><code>--with-isl-lib=<var>pathname</var></code></span></dt> 1747 <dd><p>If you do not have the isl library installed in a standard location and you 1748 want to build GCC, you can explicitly specify the directory where it is 1749 installed (‘<samp>--with-isl=<var>islinstalldir</var></samp>’). The 1750 <samp>--with-isl=<var>islinstalldir</var></samp> option is shorthand for 1751 <samp>--with-isl-lib=<var>islinstalldir</var>/lib</samp> and 1752 <samp>--with-isl-include=<var>islinstalldir</var>/include</samp>. If this 1753 shorthand assumption is not correct, you can use the explicit 1754 include and lib options directly. 1755 </p> 1756 <p>These flags are applicable to the host platform only. When building 1757 a cross compiler, they will not be used to configure target libraries. 1758 </p> 1759 </dd> 1760 <dt><span><code>--with-stage1-ldflags=<var>flags</var></code></span></dt> 1761 <dd><p>This option may be used to set linker flags to be used when linking 1762 stage 1 of GCC. These are also used when linking GCC if configured with 1763 <samp>--disable-bootstrap</samp>. If <samp>--with-stage1-libs</samp> is not set to a 1764 value, then the default is ‘<samp>-static-libstdc++ -static-libgcc</samp>’, if 1765 supported. 1766 </p> 1767 </dd> 1768 <dt><span><code>--with-stage1-libs=<var>libs</var></code></span></dt> 1769 <dd><p>This option may be used to set libraries to be used when linking stage 1 1770 of GCC. These are also used when linking GCC if configured with 1771 <samp>--disable-bootstrap</samp>. 1772 </p> 1773 </dd> 1774 <dt><span><code>--with-boot-ldflags=<var>flags</var></code></span></dt> 1775 <dd><p>This option may be used to set linker flags to be used when linking 1776 stage 2 and later when bootstrapping GCC. If –with-boot-libs 1777 is not is set to a value, then the default is 1778 ‘<samp>-static-libstdc++ -static-libgcc</samp>’. 1779 </p> 1780 </dd> 1781 <dt><span><code>--with-boot-libs=<var>libs</var></code></span></dt> 1782 <dd><p>This option may be used to set libraries to be used when linking stage 2 1783 and later when bootstrapping GCC. 1784 </p> 1785 </dd> 1786 <dt><span><code>--with-debug-prefix-map=<var>map</var></code></span></dt> 1787 <dd><p>Convert source directory names using <samp>-fdebug-prefix-map</samp> when 1788 building runtime libraries. ‘<samp><var>map</var></samp>’ is a space-separated 1789 list of maps of the form ‘<samp><var>old</var>=<var>new</var></samp>’. 1790 </p> 1791 </dd> 1792 <dt><span><code>--enable-linker-build-id</code></span></dt> 1793 <dd><p>Tells GCC to pass <samp>--build-id</samp> option to the linker for all final 1794 links (links performed without the <samp>-r</samp> or <samp>--relocatable</samp> 1795 option), if the linker supports it. If you specify 1796 <samp>--enable-linker-build-id</samp>, but your linker does not 1797 support <samp>--build-id</samp> option, a warning is issued and the 1798 <samp>--enable-linker-build-id</samp> option is ignored. The default is off. 1799 </p> 1800 </dd> 1801 <dt><span><code>--with-linker-hash-style=<var>choice</var></code></span></dt> 1802 <dd><p>Tells GCC to pass <samp>--hash-style=<var>choice</var></samp> option to the 1803 linker for all final links. <var>choice</var> can be one of 1804 ‘<samp>sysv</samp>’, ‘<samp>gnu</samp>’, and ‘<samp>both</samp>’ where ‘<samp>sysv</samp>’ is the default. 1805 </p> 1806 </dd> 1807 <dt><span><code>--enable-gnu-unique-object</code></span></dt> 1808 <dt><span><code>--disable-gnu-unique-object</code></span></dt> 1809 <dd><p>Tells GCC to use the gnu_unique_object relocation for C++ template 1810 static data members and inline function local statics. Enabled by 1811 default for a toolchain with an assembler that accepts it and 1812 GLIBC 2.11 or above, otherwise disabled. 1813 </p> 1814 </dd> 1815 <dt><span><code>--with-diagnostics-color=<var>choice</var></code></span></dt> 1816 <dd><p>Tells GCC to use <var>choice</var> as the default for <samp>-fdiagnostics-color=</samp> 1817 option (if not used explicitly on the command line). <var>choice</var> 1818 can be one of ‘<samp>never</samp>’, ‘<samp>auto</samp>’, ‘<samp>always</samp>’, and ‘<samp>auto-if-env</samp>’ 1819 where ‘<samp>auto</samp>’ is the default. ‘<samp>auto-if-env</samp>’ makes 1820 <samp>-fdiagnostics-color=auto</samp> the default if <code>GCC_COLORS</code> 1821 is present and non-empty in the environment of the compiler, and 1822 <samp>-fdiagnostics-color=never</samp> otherwise. 1823 </p> 1824 </dd> 1825 <dt><span><code>--with-diagnostics-urls=<var>choice</var></code></span></dt> 1826 <dd><p>Tells GCC to use <var>choice</var> as the default for <samp>-fdiagnostics-urls=</samp> 1827 option (if not used explicitly on the command line). <var>choice</var> 1828 can be one of ‘<samp>never</samp>’, ‘<samp>auto</samp>’, ‘<samp>always</samp>’, and ‘<samp>auto-if-env</samp>’ 1829 where ‘<samp>auto</samp>’ is the default. ‘<samp>auto-if-env</samp>’ makes 1830 <samp>-fdiagnostics-urls=auto</samp> the default if <code>GCC_URLS</code> 1831 or <code>TERM_URLS</code> is present and non-empty in the environment of the 1832 compiler, and <samp>-fdiagnostics-urls=never</samp> otherwise. 1833 </p> 1834 </dd> 1835 <dt><span><code>--enable-lto</code></span></dt> 1836 <dt><span><code>--disable-lto</code></span></dt> 1837 <dd><p>Enable support for link-time optimization (LTO). This is enabled by 1838 default, and may be disabled using <samp>--disable-lto</samp>. 1839 </p> 1840 </dd> 1841 <dt><span><code>--enable-linker-plugin-configure-flags=FLAGS</code></span></dt> 1842 <dt><span><code>--enable-linker-plugin-flags=FLAGS</code></span></dt> 1843 <dd><p>By default, linker plugins (such as the LTO plugin) are built for the 1844 host system architecture. For the case that the linker has a 1845 different (but run-time compatible) architecture, these flags can be 1846 specified to build plugins that are compatible to the linker. For 1847 example, if you are building GCC for a 64-bit x86_64 1848 (‘<samp>x86_64-pc-linux-gnu</samp>’) host system, but have a 32-bit x86 1849 GNU/Linux (‘<samp>i686-pc-linux-gnu</samp>’) linker executable (which is 1850 executable on the former system), you can configure GCC as follows for 1851 getting compatible linker plugins: 1852 </p> 1853 <div class="example"> 1854 <pre class="example">% <var>srcdir</var>/configure \ 1855 --host=x86_64-pc-linux-gnu \ 1856 --enable-linker-plugin-configure-flags=--host=i686-pc-linux-gnu \ 1857 --enable-linker-plugin-flags='CC=gcc\ -m32\ -Wl,-rpath,[...]/i686-pc-linux-gnu/lib' 1858 </pre></div> 1859 1860 </dd> 1861 <dt><span><code>--with-plugin-ld=<var>pathname</var></code></span></dt> 1862 <dd><p>Enable an alternate linker to be used at link-time optimization (LTO) 1863 link time when <samp>-fuse-linker-plugin</samp> is enabled. 1864 This linker should have plugin support such as gold starting with 1865 version 2.20 or GNU ld starting with version 2.21. 1866 See <samp>-fuse-linker-plugin</samp> for details. 1867 </p> 1868 </dd> 1869 <dt><span><code>--enable-canonical-system-headers</code></span></dt> 1870 <dt><span><code>--disable-canonical-system-headers</code></span></dt> 1871 <dd><p>Enable system header path canonicalization for <samp>libcpp</samp>. This can 1872 produce shorter header file paths in diagnostics and dependency output 1873 files, but these changed header paths may conflict with some compilation 1874 environments. Enabled by default, and may be disabled using 1875 <samp>--disable-canonical-system-headers</samp>. 1876 </p> 1877 </dd> 1878 <dt><span><code>--with-glibc-version=<var>major</var>.<var>minor</var></code></span></dt> 1879 <dd><p>Tell GCC that when the GNU C Library (glibc) is used on the target it 1880 will be version <var>major</var>.<var>minor</var> or later. Normally this can 1881 be detected from the C library’s header files, but this option may be 1882 needed when bootstrapping a cross toolchain without the header files 1883 available for building the initial bootstrap compiler. 1884 </p> 1885 <p>If GCC is configured with some multilibs that use glibc and some that 1886 do not, this option applies only to the multilibs that use glibc. 1887 However, such configurations may not work well as not all the relevant 1888 configuration in GCC is on a per-multilib basis. 1889 </p> 1890 </dd> 1891 <dt><span><code>--enable-as-accelerator-for=<var>target</var></code></span></dt> 1892 <dd><p>Build as offload target compiler. Specify offload host triple by <var>target</var>. 1893 </p> 1894 </dd> 1895 <dt><span><code>--enable-offload-targets=<var>target1</var>[=<var>path1</var>],…,<var>targetN</var>[=<var>pathN</var>]</code></span></dt> 1896 <dd><p>Enable offloading to targets <var>target1</var>, …, <var>targetN</var>. 1897 Offload compilers are expected to be already installed. Default search 1898 path for them is <samp><var>exec-prefix</var></samp>, but it can be changed by 1899 specifying paths <var>path1</var>, …, <var>pathN</var>. 1900 </p> 1901 <div class="example"> 1902 <pre class="example">% <var>srcdir</var>/configure \ 1903 --enable-offload-targets=x86_64-intelmicemul-linux-gnu=/path/to/x86_64/compiler,nvptx-none 1904 </pre></div> 1905 1906 </dd> 1907 <dt><span><code>--enable-offload-defaulted</code></span></dt> 1908 <dd> 1909 <p>Tell GCC that configured but not installed offload compilers and libgomp 1910 plugins are silently ignored. Useful for distribution compilers where 1911 those are in separate optional packages and where the presence or absence 1912 of those optional packages should determine the actual supported offloading 1913 target set rather than the GCC configure-time selection. 1914 </p> 1915 </dd> 1916 <dt><span><code>--with-hsa-runtime=<var>pathname</var></code></span></dt> 1917 <dt><span><code>--with-hsa-runtime-include=<var>pathname</var></code></span></dt> 1918 <dt><span><code>--with-hsa-runtime-lib=<var>pathname</var></code></span></dt> 1919 <dd> 1920 <p>If you configure GCC with offloading which uses an HSA run-time such as 1921 AMDGCN but do not have the HSA run-time library installed in a standard 1922 location then you can explicitly specify the directory where they are 1923 installed. The <samp>--with-hsa-runtime=<var>hsainstalldir</var></samp> option 1924 is a shorthand for 1925 <samp>--with-hsa-runtime-lib=<var>hsainstalldir</var>/lib</samp> and 1926 <samp>--with-hsa-runtime-include=<var>hsainstalldir</var>/include</samp>. 1927 </p> 1928 </dd> 1929 <dt><span><code>--enable-cet</code></span></dt> 1930 <dt><span><code>--disable-cet</code></span></dt> 1931 <dd><p>Enable building target run-time libraries with control-flow 1932 instrumentation, see <samp>-fcf-protection</samp> option. When 1933 <code>--enable-cet</code> is specified target libraries are configured 1934 to add <samp>-fcf-protection</samp> and, if needed, other target 1935 specific options to a set of building options. 1936 </p> 1937 <p><code>--enable-cet=auto</code> is default. CET is enabled on Linux/x86 if 1938 target binutils supports <code>Intel CET</code> instructions and disabled 1939 otherwise. In this case, the target libraries are configured to get 1940 additional <samp>-fcf-protection</samp> option. 1941 </p> 1942 </dd> 1943 <dt><span><code>--with-riscv-attribute=‘<samp>yes</samp>’, ‘<samp>no</samp>’ or ‘<samp>default</samp>’</code></span></dt> 1944 <dd><p>Generate RISC-V attribute by default, in order to record extra build 1945 information in object. 1946 </p> 1947 <p>The option is disabled by default. It is enabled on RISC-V/ELF (bare-metal) 1948 target if target binutils supported. 1949 </p> 1950 </dd> 1951 <dt><span><code>--enable-s390-excess-float-precision</code></span></dt> 1952 <dt><span><code>--disable-s390-excess-float-precision</code></span></dt> 1953 <dd><p>On s390(x) targets, enable treatment of float expressions with double precision 1954 when in standards-compliant mode (e.g., when <code>--std=c99</code> or 1955 <code>-fexcess-precision=standard</code> are given). 1956 </p> 1957 <p>For a native build and cross compiles that have target headers, the option’s 1958 default is derived from glibc’s behavior. When glibc clamps float_t to double, 1959 GCC follows and enables the option. For other cross compiles, the default is 1960 disabled. 1961 </p> 1962 </dd> 1963 <dt><span><code>--with-zstd=<var>pathname</var></code></span></dt> 1964 <dt><span><code>--with-zstd-include=<var>pathname</var></code></span></dt> 1965 <dt><span><code>--with-zstd-lib=<var>pathname</var></code></span></dt> 1966 <dd><p>If you do not have the <code>zstd</code> library installed in a standard 1967 location and you want to build GCC, you can explicitly specify the 1968 directory where it is installed (‘<samp>--with-zstd=<var>zstdinstalldir</var></samp>’). 1969 The <samp>--with-zstd=<var>zstdinstalldir</var></samp> option is shorthand for 1970 <samp>--with-zstd-lib=<var>zstdinstalldir</var>/lib</samp> and 1971 <samp>--with-zstd-include=<var>zstdinstalldir</var>/include</samp>. If this 1972 shorthand assumption is not correct, you can use the explicit 1973 include and lib options directly. 1974 </p> 1975 <p>These flags are applicable to the host platform only. When building 1976 a cross compiler, they will not be used to configure target libraries. 1977 </p></dd> 1978 </dl> 1979 1980 <span id="Cross-Compiler-Specific-Options"></span><h4 class="subheading">Cross-Compiler-Specific Options</h4> 1981 <p>The following options only apply to building cross compilers. 1982 </p> 1983 <dl compact="compact"> 1984 <dt><span><code>--with-toolexeclibdir=<var>dir</var></code></span></dt> 1985 <dd><p>Specify the installation directory for libraries built with a cross compiler. 1986 The default is <samp>${gcc_tooldir}/lib</samp>. 1987 </p> 1988 </dd> 1989 <dt><span><code>--with-sysroot</code></span></dt> 1990 <dt><span><code>--with-sysroot=<var>dir</var></code></span></dt> 1991 <dd><p>Tells GCC to consider <var>dir</var> as the root of a tree that contains 1992 (a subset of) the root filesystem of the target operating system. 1993 Target system headers, libraries and run-time object files will be 1994 searched for in there. More specifically, this acts as if 1995 <samp>--sysroot=<var>dir</var></samp> was added to the default options of the built 1996 compiler. The specified directory is not copied into the 1997 install tree, unlike the options <samp>--with-headers</samp> and 1998 <samp>--with-libs</samp> that this option obsoletes. The default value, 1999 in case <samp>--with-sysroot</samp> is not given an argument, is 2000 <samp>${gcc_tooldir}/sys-root</samp>. If the specified directory is a 2001 subdirectory of <samp>${exec_prefix}</samp>, then it will be found relative to 2002 the GCC binaries if the installation tree is moved. 2003 </p> 2004 <p>This option affects the system root for the compiler used to build 2005 target libraries (which runs on the build system) and the compiler newly 2006 installed with <code>make install</code>; it does not affect the compiler which is 2007 used to build GCC itself. 2008 </p> 2009 <p>If you specify the <samp>--with-native-system-header-dir=<var>dirname</var></samp> 2010 option then the compiler will search that directory within <var>dirname</var> for 2011 native system headers rather than the default <samp>/usr/include</samp>. 2012 </p> 2013 </dd> 2014 <dt><span><code>--with-build-sysroot</code></span></dt> 2015 <dt><span><code>--with-build-sysroot=<var>dir</var></code></span></dt> 2016 <dd><p>Tells GCC to consider <var>dir</var> as the system root (see 2017 <samp>--with-sysroot</samp>) while building target libraries, instead of 2018 the directory specified with <samp>--with-sysroot</samp>. This option is 2019 only useful when you are already using <samp>--with-sysroot</samp>. You 2020 can use <samp>--with-build-sysroot</samp> when you are configuring with 2021 <samp>--prefix</samp> set to a directory that is different from the one in 2022 which you are installing GCC and your target libraries. 2023 </p> 2024 <p>This option affects the system root for the compiler used to build 2025 target libraries (which runs on the build system); it does not affect 2026 the compiler which is used to build GCC itself. 2027 </p> 2028 <p>If you specify the <samp>--with-native-system-header-dir=<var>dirname</var></samp> 2029 option then the compiler will search that directory within <var>dirname</var> for 2030 native system headers rather than the default <samp>/usr/include</samp>. 2031 </p> 2032 </dd> 2033 <dt><span><code>--with-headers</code></span></dt> 2034 <dt><span><code>--with-headers=<var>dir</var></code></span></dt> 2035 <dd><p>Deprecated in favor of <samp>--with-sysroot</samp>. 2036 Specifies that target headers are available when building a cross compiler. 2037 The <var>dir</var> argument specifies a directory which has the target include 2038 files. These include files will be copied into the <samp>gcc</samp> install 2039 directory. <em>This option with the <var>dir</var> argument is required</em> when 2040 building a cross compiler, if <samp><var>prefix</var>/<var>target</var>/sys-include</samp> 2041 doesn’t pre-exist. If <samp><var>prefix</var>/<var>target</var>/sys-include</samp> does 2042 pre-exist, the <var>dir</var> argument may be omitted. <code>fixincludes</code> 2043 will be run on these files to make them compatible with GCC. 2044 </p> 2045 </dd> 2046 <dt><span><code>--without-headers</code></span></dt> 2047 <dd><p>Tells GCC not use any target headers from a libc when building a cross 2048 compiler. When crossing to GNU/Linux, you need the headers so GCC 2049 can build the exception handling for libgcc. 2050 </p> 2051 </dd> 2052 <dt><span><code>--with-libs</code></span></dt> 2053 <dt><span><code>--with-libs="<var>dir1</var> <var>dir2</var> … <var>dirN</var>"</code></span></dt> 2054 <dd><p>Deprecated in favor of <samp>--with-sysroot</samp>. 2055 Specifies a list of directories which contain the target runtime 2056 libraries. These libraries will be copied into the <samp>gcc</samp> install 2057 directory. If the directory list is omitted, this option has no 2058 effect. 2059 </p> 2060 </dd> 2061 <dt><span><code>--with-newlib</code></span></dt> 2062 <dd><p>Specifies that ‘<samp>newlib</samp>’ is 2063 being used as the target C library. This causes <code>__eprintf</code> to be 2064 omitted from <samp>libgcc.a</samp> on the assumption that it will be provided by 2065 ‘<samp>newlib</samp>’. 2066 </p> 2067 <a name="avr"></a> 2068 </dd> 2069 <dt><span><code>--with-avrlibc</code></span></dt> 2070 <dd><p>Only supported for the AVR target. Specifies that ‘<samp>AVR-Libc</samp>’ is 2071 being used as the target C library. This causes float support 2072 functions like <code>__addsf3</code> to be omitted from <samp>libgcc.a</samp> on 2073 the assumption that it will be provided by <samp>libm.a</samp>. For more 2074 technical details, cf. <a href="https://gcc.gnu.org/PR54461">PR54461</a>. 2075 It is not supported for 2076 RTEMS configurations, which currently use newlib. The option is 2077 supported since version 4.7.2 and is the default in 4.8.0 and newer. 2078 </p> 2079 </dd> 2080 <dt><span><code>--with-double={32|64|32,64|64,32}</code></span></dt> 2081 <dt><span><code>--with-long-double={32|64|32,64|64,32|double}</code></span></dt> 2082 <dd><p>Only supported for the AVR target since version 10. 2083 Specify the default layout available for the C/C++ ‘<samp>double</samp>’ 2084 and ‘<samp>long double</samp>’ type, respectively. The following rules apply: 2085 </p><ul> 2086 <li> The first value after the ‘<samp>=</samp>’ specifies the default layout (in bits) 2087 of the type and also the default for the <samp>-mdouble=</samp> resp. 2088 <samp>-mlong-double=</samp> compiler option. 2089 </li><li> If more than one value is specified, respective multilib variants are 2090 available, and <samp>-mdouble=</samp> resp. <samp>-mlong-double=</samp> acts 2091 as a multilib option. 2092 </li><li> If <samp>--with-long-double=double</samp> is specified, ‘<samp>double</samp>’ and 2093 ‘<samp>long double</samp>’ will have the same layout. 2094 </li><li> The defaults are <samp>--with-long-double=64,32</samp> and 2095 <samp>--with-double=32,64</samp>. The default ‘<samp>double</samp>’ layout imposed by 2096 the latter is compatible with older versions of the compiler that implement 2097 ‘<samp>double</samp>’ as a 32-bit type, which does not comply to the language standard. 2098 </li></ul> 2099 <p>Not all combinations of <samp>--with-double=</samp> and 2100 <samp>--with-long-double=</samp> are valid. For example, the combination 2101 <samp>--with-double=32,64</samp> <samp>--with-long-double=32</samp> will be 2102 rejected because the first option specifies the availability of 2103 multilibs for ‘<samp>double</samp>’, whereas the second option implies 2104 that ‘<samp>long double</samp>’ — and hence also ‘<samp>double</samp>’ — is always 2105 32 bits wide. 2106 </p> 2107 </dd> 2108 <dt><span><code>--with-double-comparison={tristate|bool|libf7}</code></span></dt> 2109 <dd><p>Only supported for the AVR target since version 10. 2110 Specify what result format is returned by library functions that 2111 compare 64-bit floating point values (<code>DFmode</code>). 2112 The GCC default is ‘<samp>tristate</samp>’. If the floating point 2113 implementation returns a boolean instead, set it to ‘<samp>bool</samp>’. 2114 </p> 2115 </dd> 2116 <dt><span><code>--with-libf7={libgcc|math|math-symbols|no}</code></span></dt> 2117 <dd><p>Only supported for the AVR target since version 10. 2118 Specify to which degree code from LibF7 is included in libgcc. 2119 LibF7 is an ad-hoc, AVR-specific, 64-bit floating point emulation 2120 written in C and (inline) assembly. ‘<samp>libgcc</samp>’ adds support 2121 for functions that one would usually expect in libgcc like double addition, 2122 double comparisons and double conversions. ‘<samp>math</samp>’ also adds routines 2123 that one would expect in <samp>libm.a</samp>, but with <code>__</code> (two underscores) 2124 prepended to the symbol names as specified by <samp>math.h</samp>. 2125 ‘<samp>math-symbols</samp>’ also defines weak aliases for the functions 2126 declared in <samp>math.h</samp>. However, <code>--with-libf7</code> won’t 2127 install no <samp>math.h</samp> header file whatsoever, this file must come 2128 from elsewhere. This option sets <samp>--with-double-comparison</samp> 2129 to ‘<samp>bool</samp>’. 2130 </p> 2131 </dd> 2132 <dt><span><code>--with-nds32-lib=<var>library</var></code></span></dt> 2133 <dd><p>Specifies that <var>library</var> setting is used for building <samp>libgcc.a</samp>. 2134 Currently, the valid <var>library</var> is ‘<samp>newlib</samp>’ or ‘<samp>mculib</samp>’. 2135 This option is only supported for the NDS32 target. 2136 </p> 2137 </dd> 2138 <dt><span><code>--with-build-time-tools=<var>dir</var></code></span></dt> 2139 <dd><p>Specifies where to find the set of target tools (assembler, linker, etc.) 2140 that will be used while building GCC itself. This option can be useful 2141 if the directory layouts are different between the system you are building 2142 GCC on, and the system where you will deploy it. 2143 </p> 2144 <p>For example, on an ‘<samp>ia64-hp-hpux</samp>’ system, you may have the GNU 2145 assembler and linker in <samp>/usr/bin</samp>, and the native tools in a 2146 different path, and build a toolchain that expects to find the 2147 native tools in <samp>/usr/bin</samp>. 2148 </p> 2149 <p>When you use this option, you should ensure that <var>dir</var> includes 2150 <code>ar</code>, <code>as</code>, <code>ld</code>, <code>nm</code>, 2151 <code>ranlib</code> and <code>strip</code> if necessary, and possibly 2152 <code>objdump</code>. Otherwise, GCC may use an inconsistent set of 2153 tools. 2154 </p></dd> 2155 </dl> 2156 2157 <span id="Overriding-configure-test-results"></span><h4 class="subsubheading">Overriding <code>configure</code> test results</h4> 2158 2159 <p>Sometimes, it might be necessary to override the result of some 2160 <code>configure</code> test, for example in order to ease porting to a new 2161 system or work around a bug in a test. The toplevel <code>configure</code> 2162 script provides three variables for this: 2163 </p> 2164 <dl compact="compact"> 2165 <dt id='index-build_005fconfigargs'><span><code>build_configargs</code><a href='#index-build_005fconfigargs' class='copiable-anchor'> ¶</a></span></dt> 2166 <dd><p>The contents of this variable is passed to all build <code>configure</code> 2167 scripts. 2168 </p> 2169 </dd> 2170 <dt id='index-host_005fconfigargs'><span><code>host_configargs</code><a href='#index-host_005fconfigargs' class='copiable-anchor'> ¶</a></span></dt> 2171 <dd><p>The contents of this variable is passed to all host <code>configure</code> 2172 scripts. 2173 </p> 2174 </dd> 2175 <dt id='index-target_005fconfigargs'><span><code>target_configargs</code><a href='#index-target_005fconfigargs' class='copiable-anchor'> ¶</a></span></dt> 2176 <dd><p>The contents of this variable is passed to all target <code>configure</code> 2177 scripts. 2178 </p> 2179 </dd> 2180 </dl> 2181 2182 <p>In order to avoid shell and <code>make</code> quoting issues for complex 2183 overrides, you can pass a setting for <code>CONFIG_SITE</code> and set 2184 variables in the site file. 2185 </p> 2186 <span id="Objective-C-Specific-Options"></span><h4 class="subheading">Objective-C-Specific Options</h4> 2187 2188 <p>The following options apply to the build of the Objective-C runtime library. 2189 </p> 2190 <dl compact="compact"> 2191 <dt><span><code>--enable-objc-gc</code></span></dt> 2192 <dd><p>Specify that an additional variant of the GNU Objective-C runtime library 2193 is built, using an external build of the Boehm-Demers-Weiser garbage 2194 collector (<a href="https://www.hboehm.info/gc/">https://www.hboehm.info/gc/</a>). This library needs to be 2195 available for each multilib variant, unless configured with 2196 <samp>--enable-objc-gc=‘<samp>auto</samp>’</samp> in which case the build of the 2197 additional runtime library is skipped when not available and the build 2198 continues. 2199 </p> 2200 </dd> 2201 <dt><span><code>--with-target-bdw-gc=<var>list</var></code></span></dt> 2202 <dt><span><code>--with-target-bdw-gc-include=<var>list</var></code></span></dt> 2203 <dt><span><code>--with-target-bdw-gc-lib=<var>list</var></code></span></dt> 2204 <dd><p>Specify search directories for the garbage collector header files and 2205 libraries. <var>list</var> is a comma separated list of key value pairs of the 2206 form ‘<samp><var>multilibdir</var>=<var>path</var></samp>’, where the default multilib key 2207 is named as ‘<samp>.</samp>’ (dot), or is omitted (e.g. 2208 ‘<samp>--with-target-bdw-gc=/opt/bdw-gc,32=/opt-bdw-gc32</samp>’). 2209 </p> 2210 <p>The options <samp>--with-target-bdw-gc-include</samp> and 2211 <samp>--with-target-bdw-gc-lib</samp> must always be specified together 2212 for each multilib variant and they take precedence over 2213 <samp>--with-target-bdw-gc</samp>. If <samp>--with-target-bdw-gc-include</samp> 2214 is missing values for a multilib, then the value for the default 2215 multilib is used (e.g. ‘<samp>--with-target-bdw-gc-include=/opt/bdw-gc/include</samp>’ 2216 ‘<samp>--with-target-bdw-gc-lib=/opt/bdw-gc/lib64,32=/opt-bdw-gc/lib32</samp>’). 2217 If none of these options are specified, the library is assumed in 2218 default locations. 2219 </p></dd> 2220 </dl> 2221 2222 <span id="D-Specific-Options"></span><h4 class="subheading">D-Specific Options</h4> 2223 2224 <p>The following options apply to the build of the D runtime library. 2225 </p> 2226 <dl compact="compact"> 2227 <dt><span><code>--enable-libphobos-checking</code></span></dt> 2228 <dt><span><code>--disable-libphobos-checking</code></span></dt> 2229 <dt><span><code>--enable-libphobos-checking=<var>list</var></code></span></dt> 2230 <dd><p>This option controls whether run-time checks and contracts are compiled into 2231 the D runtime library. When the option is not specified, the library is built 2232 with ‘<samp>release</samp>’ checking. When the option is specified without a 2233 <var>list</var>, the result is the same as ‘<samp>--enable-libphobos-checking=yes</samp>’. 2234 Likewise, ‘<samp>--disable-libphobos-checking</samp>’ is equivalent to 2235 ‘<samp>--enable-libphobos-checking=no</samp>’. 2236 </p> 2237 <p>The categories of checks available in <var>list</var> are ‘<samp>yes</samp>’ (compiles 2238 libphobos with <samp>-fno-release</samp>), ‘<samp>no</samp>’ (compiles libphobos with 2239 <samp>-frelease</samp>), ‘<samp>all</samp>’ (same as ‘<samp>yes</samp>’), ‘<samp>none</samp>’ or 2240 ‘<samp>release</samp>’ (same as ‘<samp>no</samp>’). 2241 </p> 2242 <p>Individual checks available in <var>list</var> are ‘<samp>assert</samp>’ (compiles libphobos 2243 with an extra option <samp>-fassert</samp>). 2244 </p> 2245 </dd> 2246 <dt><span><code>--with-libphobos-druntime-only</code></span></dt> 2247 <dt><span><code>--with-libphobos-druntime-only=<var>choice</var></code></span></dt> 2248 <dd><p>Specify whether to build only the core D runtime library (druntime), or both 2249 the core and standard library (phobos) into libphobos. This is useful for 2250 targets that have full support in druntime, but no or incomplete support 2251 in phobos. <var>choice</var> can be one of ‘<samp>auto</samp>’, ‘<samp>yes</samp>’, and ‘<samp>no</samp>’ 2252 where ‘<samp>auto</samp>’ is the default. 2253 </p> 2254 <p>When the option is not specified, the default choice ‘<samp>auto</samp>’ means that it 2255 is inferred whether the target has support for the phobos standard library. 2256 When the option is specified without a <var>choice</var>, the result is the same as 2257 ‘<samp>--with-libphobos-druntime-only=yes</samp>’. 2258 </p> 2259 </dd> 2260 <dt><span><code>--with-target-system-zlib</code></span></dt> 2261 <dd><p>Use installed ‘<samp>zlib</samp>’ rather than that included with GCC. This needs 2262 to be available for each multilib variant, unless configured with 2263 <samp>--with-target-system-zlib=‘<samp>auto</samp>’</samp> in which case the GCC included 2264 ‘<samp>zlib</samp>’ is only used when the system installed library is not available. 2265 </p></dd> 2266 </dl> 2267 2268 <hr /> 2269 <p> 2270 <p><a href="./index.html">Return to the GCC Installation page</a> 2271 </p> 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 </body> 2283 </html> 2284
Indexes created Thu Jul 16 00:26:27 UTC 2026