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Using these can lead to various sorts of build 105 problems. To avoid this issue, set the <code>PWDCMD</code> environment 106 variable to an automounter-aware <code>pwd</code> command, e.g., 107 <code>pawd</code> or ‘<samp>amq -w</samp>’, during the configuration and build 108 phases. 109 </p> 110 <p>First, we <strong>highly</strong> recommend that GCC be built into a 111 separate directory from the sources which does <strong>not</strong> reside 112 within the source tree. This is how we generally build GCC; building 113 where <var>objdir</var> is a subdirectory of <var>srcdir</var> should work as well; 114 building where <var>objdir</var> == <var>srcdir</var> is unsupported. 115 </p> 116 <p>If you have previously built GCC in the same directory for a 117 different target machine, do ‘<samp>make distclean</samp>’ to delete all files 118 that might be invalid. One of the files this deletes is <samp>Makefile</samp>; 119 if ‘<samp>make distclean</samp>’ complains that <samp>Makefile</samp> does not exist 120 or issues a message like “don’t know how to make distclean” it probably 121 means that the directory is already suitably clean. However, with the 122 recommended method of building in a separate <var>objdir</var>, you should 123 simply use a different <var>objdir</var> for each target. 124 </p> 125 <p>Second, when configuring a native system, either <code>cc</code> or 126 <code>gcc</code> must be in your path or you must set <code>CC</code> in 127 your environment before running configure. Otherwise the configuration 128 scripts may fail. 129 </p> 130 131 <p>To configure GCC: 132 </p> 133 <div class="smallexample"> 134 <pre class="smallexample">% mkdir <var>objdir</var> 135 % cd <var>objdir</var> 136 % <var>srcdir</var>/configure [<var>options</var>] [<var>target</var>] 137 </pre></div> 138 139 <a name="Distributor-options"></a> 140 <h3 class="heading">Distributor options</h3> 141 142 <p>If you will be distributing binary versions of GCC, with modifications 143 to the source code, you should use the options described in this 144 section to make clear that your version contains modifications. 145 </p> 146 <dl compact="compact"> 147 <dt><code>--with-pkgversion=<var>version</var></code></dt> 148 <dd><p>Specify a string that identifies your package. You may wish 149 to include a build number or build date. This version string will be 150 included in the output of <code>gcc --version</code>. This suffix does 151 not replace the default version string, only the ‘<samp>GCC</samp>’ part. 152 </p> 153 <p>The default value is ‘<samp>GCC</samp>’. 154 </p> 155 </dd> 156 <dt><code>--with-bugurl=<var>url</var></code></dt> 157 <dd><p>Specify the URL that users should visit if they wish to report a bug. 158 You are of course welcome to forward bugs reported to you to the FSF, 159 if you determine that they are not bugs in your modifications. 160 </p> 161 <p>The default value refers to the FSF’s GCC bug tracker. 162 </p> 163 </dd> 164 <dt><code>--with-documentation-root-url=<var>url</var></code></dt> 165 <dd><p>Specify the URL root that contains GCC option documentation. The <var>url</var> 166 should end with a <code>/</code> character. 167 </p> 168 <p>The default value is <a href="https://gcc.gnu.org/onlinedocs/">https://gcc.gnu.org/onlinedocs/</a> 169 on the GCC main development trunk. On release branches, the default 170 is <code>https://gcc.gnu.org/onlinedocs/gcc-<var>major</var>.<var>minor</var>.0/</code>. 171 </p> 172 </dd> 173 <dt><code>--with-changes-root-url=<var>url</var></code></dt> 174 <dd><p>Specify the URL root that contains information about changes in GCC 175 releases like <code>gcc-<var>version</var>/changes.html</code>. 176 The <var>url</var> should end with a <code>/</code> character. 177 </p> 178 <p>The default value is <a href="https://gcc.gnu.org/">https://gcc.gnu.org/</a>. 179 </p> 180 </dd> 181 </dl> 182 183 <a name="Host_002c-Build-and-Target-specification"></a> 184 <h3 class="heading">Host, Build and Target specification</h3> 185 186 <p>Specify the host, build and target machine configurations. You do this 187 when you run the <samp>configure</samp> script. 188 </p> 189 <p>The <em>build</em> machine is the system which you are using, the 190 <em>host</em> machine is the system where you want to run the resulting 191 compiler (normally the build machine), and the <em>target</em> machine is 192 the system for which you want the compiler to generate code. 193 </p> 194 <p>If you are building a compiler to produce code for the machine it runs 195 on (a native compiler), you normally do not need to specify any operands 196 to <samp>configure</samp>; it will try to guess the type of machine you are on 197 and use that as the build, host and target machines. So you don’t need 198 to specify a configuration when building a native compiler unless 199 <samp>configure</samp> cannot figure out what your configuration is or guesses 200 wrong. 201 </p> 202 <p>In those cases, specify the build machine’s <em>configuration name</em> 203 with the <samp>--host</samp> option; the host and target will default to be 204 the same as the host machine. 205 </p> 206 <p>Here is an example: 207 </p> 208 <div class="smallexample"> 209 <pre class="smallexample">./configure --host=x86_64-pc-linux-gnu 210 </pre></div> 211 212 <p>A configuration name may be canonical or it may be more or less 213 abbreviated (<samp>config.sub</samp> script produces canonical versions). 214 </p> 215 <p>A canonical configuration name has three parts, separated by dashes. 216 It looks like this: ‘<samp><var>cpu</var>-<var>company</var>-<var>system</var></samp>’. 217 </p> 218 <p>Here are the possible CPU types: 219 </p> 220 <blockquote> 221 <p>aarch64, aarch64_be, alpha, alpha64, amdgcn, arc, arceb, arm, armeb, avr, bfin, 222 bpf, cris, csky, epiphany, fido, fr30, frv, ft32, h8300, hppa, hppa2.0, 223 hppa64, i486, i686, ia64, iq2000, lm32, loongarch64, m32c, m32r, m32rle, m68k, 224 mcore, microblaze, microblazeel, mips, mips64, mips64el, mips64octeon, 225 mips64orion, mips64vr, mipsel, mipsisa32, mipsisa32r2, mipsisa64, mipsisa64r2, 226 mipsisa64r2el, mipsisa64sb1, mipsisa64sr71k, mipstx39, mmix, mn10300, moxie, 227 msp430, nds32be, nds32le, nios2, nvptx, or1k, pdp11, powerpc, powerpc64, 228 powerpc64le, powerpcle, pru, riscv32, riscv32be, riscv64, riscv64be, rl78, rx, 229 s390, s390x, sh, shle, sparc, sparc64, tic6x, v850, 230 v850e, v850e1, vax, visium, x86_64, xstormy16, xtensa 231 </p></blockquote> 232 233 <p>Here is a list of system types: 234 </p> 235 <blockquote> 236 <p>aix<var>version</var>, amdhsa, aout, cygwin, darwin<var>version</var>, 237 eabi, eabialtivec, eabisim, eabisimaltivec, elf, elf32, 238 elfbare, elfoabi, freebsd<var>version</var>, gnu, hpux, hpux<var>version</var>, 239 kfreebsd-gnu, kopensolaris-gnu, linux-androideabi, linux-gnu, 240 linux-gnu_altivec, linux-musl, linux-uclibc, lynxos, mingw32, mingw32crt, 241 mmixware, msdosdjgpp, netbsd, netbsdelf<var>version</var>, nto-qnx, openbsd, 242 rtems, solaris<var>version</var>, symbianelf, tpf, uclinux, uclinux_eabi, vms, 243 vxworks, vxworksae, vxworksmils 244 </p></blockquote> 245 246 <a name="Options-specification"></a> 247 <h3 class="heading">Options specification</h3> 248 249 <p>Use <var>options</var> to override several configure time options for 250 GCC. A list of supported <var>options</var> follows; ‘<samp>configure 251 --help</samp>’ may list other options, but those not listed below may not 252 work and should not normally be used. 253 </p> 254 <p>Note that each <samp>--enable</samp> option has a corresponding 255 <samp>--disable</samp> option and that each <samp>--with</samp> option has a 256 corresponding <samp>--without</samp> option. 257 </p> 258 <dl compact="compact"> 259 <dt><code>--prefix=<var>dirname</var></code></dt> 260 <dd><p>Specify the toplevel installation 261 directory. This is the recommended way to install the tools into a directory 262 other than the default. The toplevel installation directory defaults to 263 <samp>/usr/local</samp>. 264 </p> 265 <p>We <strong>highly</strong> recommend against <var>dirname</var> being the same or a 266 subdirectory of <var>objdir</var> or vice versa. If specifying a directory 267 beneath a user’s home directory tree, some shells will not expand 268 <var>dirname</var> correctly if it contains the ‘<samp>~</samp>’ metacharacter; use 269 <code>$HOME</code> instead. 270 </p> 271 <p>The following standard <code>autoconf</code> options are supported. Normally you 272 should not need to use these options. 273 </p><dl compact="compact"> 274 <dt><code>--exec-prefix=<var>dirname</var></code></dt> 275 <dd><p>Specify the toplevel installation directory for architecture-dependent 276 files. The default is <samp><var>prefix</var></samp>. 277 </p> 278 </dd> 279 <dt><code>--bindir=<var>dirname</var></code></dt> 280 <dd><p>Specify the installation directory for the executables called by users 281 (such as <code>gcc</code> and <code>g++</code>). The default is 282 <samp><var>exec-prefix</var>/bin</samp>. 283 </p> 284 </dd> 285 <dt><code>--libdir=<var>dirname</var></code></dt> 286 <dd><p>Specify the installation directory for object code libraries and 287 internal data files of GCC. The default is <samp><var>exec-prefix</var>/lib</samp>. 288 </p> 289 </dd> 290 <dt><code>--libexecdir=<var>dirname</var></code></dt> 291 <dd><p>Specify the installation directory for internal executables of GCC. 292 The default is <samp><var>exec-prefix</var>/libexec</samp>. 293 </p> 294 </dd> 295 <dt><code>--with-slibdir=<var>dirname</var></code></dt> 296 <dd><p>Specify the installation directory for the shared libgcc library. The 297 default is <samp><var>libdir</var></samp>. 298 </p> 299 </dd> 300 <dt><code>--datarootdir=<var>dirname</var></code></dt> 301 <dd><p>Specify the root of the directory tree for read-only architecture-independent 302 data files referenced by GCC. The default is <samp><var>prefix</var>/share</samp>. 303 </p> 304 </dd> 305 <dt><code>--infodir=<var>dirname</var></code></dt> 306 <dd><p>Specify the installation directory for documentation in info format. 307 The default is <samp><var>datarootdir</var>/info</samp>. 308 </p> 309 </dd> 310 <dt><code>--datadir=<var>dirname</var></code></dt> 311 <dd><p>Specify the installation directory for some architecture-independent 312 data files referenced by GCC. The default is <samp><var>datarootdir</var></samp>. 313 </p> 314 </dd> 315 <dt><code>--docdir=<var>dirname</var></code></dt> 316 <dd><p>Specify the installation directory for documentation files (other 317 than Info) for GCC. The default is <samp><var>datarootdir</var>/doc</samp>. 318 </p> 319 </dd> 320 <dt><code>--htmldir=<var>dirname</var></code></dt> 321 <dd><p>Specify the installation directory for HTML documentation files. 322 The default is <samp><var>docdir</var></samp>. 323 </p> 324 </dd> 325 <dt><code>--pdfdir=<var>dirname</var></code></dt> 326 <dd><p>Specify the installation directory for PDF documentation files. 327 The default is <samp><var>docdir</var></samp>. 328 </p> 329 </dd> 330 <dt><code>--mandir=<var>dirname</var></code></dt> 331 <dd><p>Specify the installation directory for manual pages. The default is 332 <samp><var>datarootdir</var>/man</samp>. (Note that the manual pages are only extracts 333 from the full GCC manuals, which are provided in Texinfo format. The manpages 334 are derived by an automatic conversion process from parts of the full 335 manual.) 336 </p> 337 </dd> 338 <dt><code>--with-gxx-include-dir=<var>dirname</var></code></dt> 339 <dd><p>Specify 340 the installation directory for G++ header files. The default depends 341 on other configuration options, and differs between cross and native 342 configurations. 343 </p> 344 </dd> 345 <dt><code>--with-specs=<var>specs</var></code></dt> 346 <dd><p>Specify additional command line driver SPECS. 347 This can be useful if you need to turn on a non-standard feature by 348 default without modifying the compiler’s source code, for instance 349 <samp>--with-specs=%{!fcommon:%{!fno-common:-fno-common}}</samp>. 350 See “Spec Files” in the main manual 351 </p> 352 </dd> 353 </dl> 354 355 </dd> 356 <dt><code>--program-prefix=<var>prefix</var></code></dt> 357 <dd><p>GCC supports some transformations of the names of its programs when 358 installing them. This option prepends <var>prefix</var> to the names of 359 programs to install in <var>bindir</var> (see above). For example, specifying 360 <samp>--program-prefix=foo-</samp> would result in ‘<samp>gcc</samp>’ 361 being installed as <samp>/usr/local/bin/foo-gcc</samp>. 362 </p> 363 </dd> 364 <dt><code>--program-suffix=<var>suffix</var></code></dt> 365 <dd><p>Appends <var>suffix</var> to the names of programs to install in <var>bindir</var> 366 (see above). For example, specifying <samp>--program-suffix=-3.1</samp> 367 would result in ‘<samp>gcc</samp>’ being installed as 368 <samp>/usr/local/bin/gcc-3.1</samp>. 369 </p> 370 </dd> 371 <dt><code>--program-transform-name=<var>pattern</var></code></dt> 372 <dd><p>Applies the ‘<samp>sed</samp>’ script <var>pattern</var> to be applied to the names 373 of programs to install in <var>bindir</var> (see above). <var>pattern</var> has to 374 consist of one or more basic ‘<samp>sed</samp>’ editing commands, separated by 375 semicolons. For example, if you want the ‘<samp>gcc</samp>’ program name to be 376 transformed to the installed program <samp>/usr/local/bin/myowngcc</samp> and 377 the ‘<samp>g++</samp>’ program name to be transformed to 378 <samp>/usr/local/bin/gspecial++</samp> without changing other program names, 379 you could use the pattern 380 <samp>--program-transform-name='s/^gcc$/myowngcc/; s/^g++$/gspecial++/'</samp> 381 to achieve this effect. 382 </p> 383 <p>All three options can be combined and used together, resulting in more 384 complex conversion patterns. As a basic rule, <var>prefix</var> (and 385 <var>suffix</var>) are prepended (appended) before further transformations 386 can happen with a special transformation script <var>pattern</var>. 387 </p> 388 <p>As currently implemented, this option only takes effect for native 389 builds; cross compiler binaries’ names are not transformed even when a 390 transformation is explicitly asked for by one of these options. 391 </p> 392 <p>For native builds, some of the installed programs are also installed 393 with the target alias in front of their name, as in 394 ‘<samp>i686-pc-linux-gnu-gcc</samp>’. All of the above transformations happen 395 before the target alias is prepended to the name—so, specifying 396 <samp>--program-prefix=foo-</samp> and <samp>program-suffix=-3.1</samp>, the 397 resulting binary would be installed as 398 <samp>/usr/local/bin/i686-pc-linux-gnu-foo-gcc-3.1</samp>. 399 </p> 400 <p>As a last shortcoming, none of the installed Ada programs are 401 transformed yet, which will be fixed in some time. 402 </p> 403 </dd> 404 <dt><code>--with-local-prefix=<var>dirname</var></code></dt> 405 <dd><p>Specify the 406 installation directory for local include files. The default is 407 <samp>/usr/local</samp>. Specify this option if you want the compiler to 408 search directory <samp><var>dirname</var>/include</samp> for locally installed 409 header files <em>instead</em> of <samp>/usr/local/include</samp>. 410 </p> 411 <p>You should specify <samp>--with-local-prefix</samp> <strong>only</strong> if your 412 site has a different convention (not <samp>/usr/local</samp>) for where to put 413 site-specific files. 414 </p> 415 <p>The default value for <samp>--with-local-prefix</samp> is <samp>/usr/local</samp> 416 regardless of the value of <samp>--prefix</samp>. Specifying 417 <samp>--prefix</samp> has no effect on which directory GCC searches for 418 local header files. This may seem counterintuitive, but actually it is 419 logical. 420 </p> 421 <p>The purpose of <samp>--prefix</samp> is to specify where to <em>install 422 GCC</em>. The local header files in <samp>/usr/local/include</samp>—if you put 423 any in that directory—are not part of GCC. They are part of other 424 programs—perhaps many others. (GCC installs its own header files in 425 another directory which is based on the <samp>--prefix</samp> value.) 426 </p> 427 <p>Both the local-prefix include directory and the GCC-prefix include 428 directory are part of GCC’s “system include” directories. Although these 429 two directories are not fixed, they need to be searched in the proper 430 order for the correct processing of the include_next directive. The 431 local-prefix include directory is searched before the GCC-prefix 432 include directory. Another characteristic of system include directories 433 is that pedantic warnings are turned off for headers in these directories. 434 </p> 435 <p>Some autoconf macros add <samp>-I <var>directory</var></samp> options to the 436 compiler command line, to ensure that directories containing installed 437 packages’ headers are searched. When <var>directory</var> is one of GCC’s 438 system include directories, GCC will ignore the option so that system 439 directories continue to be processed in the correct order. This 440 may result in a search order different from what was specified but the 441 directory will still be searched. 442 </p> 443 <p>GCC automatically searches for ordinary libraries using 444 <code>GCC_EXEC_PREFIX</code>. Thus, when the same installation prefix is 445 used for both GCC and packages, GCC will automatically search for 446 both headers and libraries. This provides a configuration that is 447 easy to use. GCC behaves in a manner similar to that when it is 448 installed as a system compiler in <samp>/usr</samp>. 449 </p> 450 <p>Sites that need to install multiple versions of GCC may not want to 451 use the above simple configuration. It is possible to use the 452 <samp>--program-prefix</samp>, <samp>--program-suffix</samp> and 453 <samp>--program-transform-name</samp> options to install multiple versions 454 into a single directory, but it may be simpler to use different prefixes 455 and the <samp>--with-local-prefix</samp> option to specify the location of the 456 site-specific files for each version. It will then be necessary for 457 users to specify explicitly the location of local site libraries 458 (e.g., with <code>LIBRARY_PATH</code>). 459 </p> 460 <p>The same value can be used for both <samp>--with-local-prefix</samp> and 461 <samp>--prefix</samp> provided it is not <samp>/usr</samp>. This can be used 462 to avoid the default search of <samp>/usr/local/include</samp>. 463 </p> 464 <p><strong>Do not</strong> specify <samp>/usr</samp> as the <samp>--with-local-prefix</samp>! 465 The directory you use for <samp>--with-local-prefix</samp> <strong>must not</strong> 466 contain any of the system’s standard header files. If it did contain 467 them, certain programs would be miscompiled (including GNU Emacs, on 468 certain targets), because this would override and nullify the header 469 file corrections made by the <code>fixincludes</code> script. 470 </p> 471 <p>Indications are that people who use this option use it based on mistaken 472 ideas of what it is for. People use it as if it specified where to 473 install part of GCC. Perhaps they make this assumption because 474 installing GCC creates the directory. 475 </p> 476 </dd> 477 <dt><code>--with-gcc-major-version-only</code></dt> 478 <dd><p>Specifies that GCC should use only the major number rather than 479 <var>major</var>.<var>minor</var>.<var>patchlevel</var> in filesystem paths. 480 </p> 481 </dd> 482 <dt><code>--with-native-system-header-dir=<var>dirname</var></code></dt> 483 <dd><p>Specifies that <var>dirname</var> is the directory that contains native system 484 header files, rather than <samp>/usr/include</samp>. This option is most useful 485 if you are creating a compiler that should be isolated from the system 486 as much as possible. It is most commonly used with the 487 <samp>--with-sysroot</samp> option and will cause GCC to search 488 <var>dirname</var> inside the system root specified by that option. 489 </p> 490 </dd> 491 <dt><code>--enable-shared[=<var>package</var>[,…]]</code></dt> 492 <dd><p>Build shared versions of libraries, if shared libraries are supported on 493 the target platform. Unlike GCC 2.95.x and earlier, shared libraries 494 are enabled by default on all platforms that support shared libraries. 495 </p> 496 <p>If a list of packages is given as an argument, build shared libraries 497 only for the listed packages. For other packages, only static libraries 498 will be built. Package names currently recognized in the GCC tree are 499 ‘<samp>libgcc</samp>’ (also known as ‘<samp>gcc</samp>’), ‘<samp>libstdc++</samp>’ (not 500 ‘<samp>libstdc++-v3</samp>’), ‘<samp>libffi</samp>’, ‘<samp>zlib</samp>’, ‘<samp>boehm-gc</samp>’, 501 ‘<samp>ada</samp>’, ‘<samp>libada</samp>’, ‘<samp>libgo</samp>’, ‘<samp>libobjc</samp>’, and ‘<samp>libphobos</samp>’. 502 Note ‘<samp>libiberty</samp>’ does not support shared libraries at all. 503 </p> 504 <p>Use <samp>--disable-shared</samp> to build only static libraries. Note that 505 <samp>--disable-shared</samp> does not accept a list of package names as 506 argument, only <samp>--enable-shared</samp> does. 507 </p> 508 <p>Contrast with <samp>--enable-host-shared</samp>, which affects <em>host</em> 509 code. 510 </p> 511 </dd> 512 <dt><code>--enable-host-shared</code></dt> 513 <dd><p>Specify that the <em>host</em> code should be built into position-independent 514 machine code (with <samp>-fPIC</samp>), allowing it to be used within shared 515 libraries, but yielding a slightly slower compiler. 516 </p> 517 <p>This option is required when building the libgccjit.so library. 518 </p> 519 <p>Contrast with <samp>--enable-shared</samp>, which affects <em>target</em> 520 libraries. 521 </p> 522 </dd> 523 <dt><code>--enable-host-pie</code></dt> 524 <dd><p>Specify that the <em>host</em> executables should be built into 525 position-independent executables (with <samp>-fPIE</samp> and <samp>-pie</samp>), 526 yielding a slightly slower compiler (but faster than 527 <samp>--enable-host-shared</samp>). Position-independent executables are loaded 528 at random addresses each time they are executed, therefore provide additional 529 protection against Return Oriented Programming (ROP) attacks. 530 </p> 531 <p><samp>--enable-host-pie</samp> may be used with <samp>--enable-host-shared</samp>, 532 in which case <samp>-fPIC</samp> is used when compiling, and <samp>-pie</samp> when 533 linking. 534 </p> 535 </dd> 536 <dt><code>--enable-host-bind-now</code></dt> 537 <dd><p>Specify that the <em>host</em> executables should be linked with the option 538 <samp>-Wl,-z,now</samp>, which means that the dynamic linker will resolve all 539 symbols when the executables are started, and that in turn allows RELRO to 540 mark the GOT read-only, resulting in better security. 541 </p> 542 </dd> 543 <dt><code><a name="with-gnu-as"></a>--with-gnu-as</code></dt> 544 <dd><p>Specify that the compiler should assume that the 545 assembler it finds is the GNU assembler. However, this does not modify 546 the rules to find an assembler and will result in confusion if the 547 assembler found is not actually the GNU assembler. (Confusion may also 548 result if the compiler finds the GNU assembler but has not been 549 configured with <samp>--with-gnu-as</samp>.) If you have more than one 550 assembler installed on your system, you may want to use this option in 551 connection with <samp>--with-as=<var>pathname</var></samp> or 552 <samp>--with-build-time-tools=<var>pathname</var></samp>. 553 </p> 554 <p>The following systems are the only ones where it makes a difference 555 whether you use the GNU assembler. On any other system, 556 <samp>--with-gnu-as</samp> has no effect. 557 </p> 558 <ul> 559 <li> ‘<samp>hppa1.0-<var>any</var>-<var>any</var></samp>’ 560 </li><li> ‘<samp>hppa1.1-<var>any</var>-<var>any</var></samp>’ 561 </li><li> ‘<samp>*-*-solaris2.11</samp>’ 562 </li></ul> 563 564 </dd> 565 <dt><code><a name="with-as"></a>--with-as=<var>pathname</var></code></dt> 566 <dd><p>Specify that the compiler should use the assembler pointed to by 567 <var>pathname</var>, rather than the one found by the standard rules to find 568 an assembler, which are: 569 </p><ul> 570 <li> Unless GCC is being built with a cross compiler, check the 571 <samp><var>libexec</var>/gcc/<var>target</var>/<var>version</var></samp> directory. 572 <var>libexec</var> defaults to <samp><var>exec-prefix</var>/libexec</samp>; 573 <var>exec-prefix</var> defaults to <var>prefix</var>, which 574 defaults to <samp>/usr/local</samp> unless overridden by the 575 <samp>--prefix=<var>pathname</var></samp> switch described above. <var>target</var> 576 is the target system triple, such as ‘<samp>sparc-sun-solaris2.11</samp>’, and 577 <var>version</var> denotes the GCC version, such as 3.0. 578 579 </li><li> If the target system is the same that you are building on, check 580 operating system specific directories. 581 582 </li><li> Check in the <code>PATH</code> for a tool whose name is prefixed by the 583 target system triple. 584 585 </li><li> Check in the <code>PATH</code> for a tool whose name is not prefixed by the 586 target system triple, if the host and target system triple are 587 the same (in other words, we use a host tool if it can be used for 588 the target as well). 589 </li></ul> 590 591 <p>You may want to use <samp>--with-as</samp> if no assembler 592 is installed in the directories listed above, or if you have multiple 593 assemblers installed and want to choose one that is not found by the 594 above rules. 595 </p> 596 </dd> 597 <dt><code><a name="with-gnu-ld"></a>--with-gnu-ld</code></dt> 598 <dd><p>Same as <a href="#with-gnu-as"><samp>--with-gnu-as</samp></a> 599 but for the linker. 600 </p> 601 </dd> 602 <dt><code>--with-ld=<var>pathname</var></code></dt> 603 <dd><p>Same as <a href="#with-as"><samp>--with-as</samp></a> 604 but for the linker. 605 </p> 606 </dd> 607 <dt><code>--with-dsymutil=<var>pathname</var></code></dt> 608 <dd><p>Same as <a href="#with-as"><samp>--with-as</samp></a> 609 but for the debug linker (only used on Darwin platforms so far). 610 </p> 611 </dd> 612 <dt><code>--with-tls=<var>dialect</var></code></dt> 613 <dd><p>Specify the default TLS dialect, for systems were there is a choice. 614 For ARM targets, possible values for <var>dialect</var> are <code>gnu</code> or 615 <code>gnu2</code>, which select between the original GNU dialect and the GNU TLS 616 descriptor-based dialect. 617 For RISC-V targets, possible values for <var>dialect</var> are <code>trad</code> or 618 <code>desc</code>, which select between the traditional GNU dialect and the GNU TLS 619 descriptor-based dialect. 620 </p> 621 </dd> 622 <dt><code>--enable-multiarch</code></dt> 623 <dd><p>Specify whether to enable or disable multiarch support. The default is 624 to check for glibc start files in a multiarch location, and enable it 625 if the files are found. The auto detection is enabled for native builds, 626 and for cross builds configured with <samp>--with-sysroot</samp>, and without 627 <samp>--with-native-system-header-dir</samp>. 628 More documentation about multiarch can be found at 629 <a href="https://wiki.debian.org/Multiarch">https://wiki.debian.org/Multiarch</a>. 630 </p> 631 </dd> 632 <dt><code>--enable-sjlj-exceptions</code></dt> 633 <dd><p>Force use of the <code>setjmp</code>/<code>longjmp</code>-based scheme for exceptions. 634 ‘<samp>configure</samp>’ ordinarily picks the correct value based on the platform. 635 Only use this option if you are sure you need a different setting. 636 </p> 637 </dd> 638 <dt><code>--enable-vtable-verify</code></dt> 639 <dd><p>Specify whether to enable or disable the vtable verification feature. 640 Enabling this feature causes libstdc++ to be built with its virtual calls 641 in verifiable mode. This means that, when linked with libvtv, every 642 virtual call in libstdc++ will verify the vtable pointer through which the 643 call will be made before actually making the call. If not linked with libvtv, 644 the verifier will call stub functions (in libstdc++ itself) and do nothing. 645 If vtable verification is disabled, then libstdc++ is not built with its 646 virtual calls in verifiable mode at all. However the libvtv library will 647 still be built (see <samp>--disable-libvtv</samp> to turn off building libvtv). 648 <samp>--disable-vtable-verify</samp> is the default. 649 </p> 650 </dd> 651 <dt><code>--disable-gcov</code></dt> 652 <dd><p>Specify that the run-time library used for coverage analysis 653 and associated host tools should not be built. 654 </p> 655 </dd> 656 <dt><code>--disable-multilib</code></dt> 657 <dd><p>Specify that multiple target 658 libraries to support different target variants, calling 659 conventions, etc. should not be built. The default is to build a 660 predefined set of them. 661 </p> 662 <p>Some targets provide finer-grained control over which multilibs are built 663 (e.g., <samp>--disable-softfloat</samp>): 664 </p><dl compact="compact"> 665 <dt><code>arm-*-*</code></dt> 666 <dd><p>fpu, 26bit, underscore, interwork, biendian, nofmult. 667 </p> 668 </dd> 669 <dt><code>m68*-*-*</code></dt> 670 <dd><p>softfloat, m68881, m68000, m68020. 671 </p> 672 </dd> 673 <dt><code>mips*-*-*</code></dt> 674 <dd><p>single-float, biendian, softfloat. 675 </p> 676 </dd> 677 <dt><code>msp430-*-*</code></dt> 678 <dd><p>no-exceptions 679 </p> 680 </dd> 681 <dt><code>powerpc*-*-*, rs6000*-*-*</code></dt> 682 <dd><p>aix64, pthread, softfloat, powercpu, powerpccpu, powerpcos, biendian, 683 sysv, aix. 684 </p> 685 </dd> 686 </dl> 687 688 </dd> 689 <dt><code>--with-multilib-list=<var>list</var></code></dt> 690 <dt><code>--without-multilib-list</code></dt> 691 <dd><p>Specify what multilibs to build. <var>list</var> is a comma separated list of 692 values, possibly consisting of a single value. Currently only implemented 693 for aarch64*-*-*, amdgcn*-*-*, arm*-*-*, loongarch*-*-*, riscv*-*-*, sh*-*-* 694 and x86-64-*-linux*. The accepted values and meaning for each target is given 695 below. 696 </p> 697 <dl compact="compact"> 698 <dt><code>aarch64*-*-*</code></dt> 699 <dd><p><var>list</var> is a comma separated list of <code>ilp32</code>, and <code>lp64</code> 700 to enable ILP32 and LP64 run-time libraries, respectively. If 701 <var>list</var> is empty, then there will be no multilibs and only the 702 default run-time library will be built. If <var>list</var> is 703 <code>default</code> or –with-multilib-list= is not specified, then the 704 default set of libraries is selected based on the value of 705 <samp>--target</samp>. 706 </p> 707 </dd> 708 <dt><code>amdgcn*-*-*</code></dt> 709 <dd><p><var>list</var> is a comma separated list of ISA names (allowed values: <code>fiji</code>, 710 <code>gfx900</code>, <code>gfx906</code>, <code>gfx908</code>, <code>gfx90a</code>, <code>gfx90c</code>, 711 <code>gfx1030</code>, <code>gfx1036</code>, <code>gfx1100</code>, <code>gfx1103</code>). 712 It ought not include the name of the default 713 ISA, specified via <samp>--with-arch</samp>. If <var>list</var> is empty, then there 714 will be no multilibs and only the default run-time library will be built. If 715 <var>list</var> is <code>default</code> or <samp>--with-multilib-list=</samp> is not 716 specified, then the default set of libraries is selected. 717 </p> 718 </dd> 719 <dt><code>arm*-*-*</code></dt> 720 <dd><p><var>list</var> is a comma separated list of <code>aprofile</code> and 721 <code>rmprofile</code> to build multilibs for A or R and M architecture 722 profiles respectively. Note that, due to some limitation of the current 723 multilib framework, using the combined <code>aprofile,rmprofile</code> 724 multilibs selects in some cases a less optimal multilib than when using 725 the multilib profile for the architecture targetted. The special value 726 <code>default</code> is also accepted and is equivalent to omitting the 727 option, i.e., only the default run-time library will be enabled. 728 </p> 729 <p><var>list</var> may instead contain <code>@name</code>, to use the multilib 730 configuration Makefile fragment <samp>name</samp> in <samp>gcc/config/arm</samp> in 731 the source tree (it is part of the corresponding sources, after all). 732 It is recommended, but not required, that files used for this purpose to 733 be named starting with <samp>t-ml-</samp>, to make their intended purpose 734 self-evident, in line with GCC conventions. Such files enable custom, 735 user-chosen multilib lists to be configured. Whether multiple such 736 files can be used together depends on the contents of the supplied 737 files. See <samp>gcc/config/arm/t-multilib</samp> and its supplementary 738 <samp>gcc/config/arm/t-*profile</samp> files for an example of what such 739 Makefile fragments might look like for this version of GCC. The macros 740 expected to be defined in these fragments are not stable across GCC 741 releases, so make sure they define the <code>MULTILIB</code>-related macros 742 expected by the version of GCC you are building. 743 See “Target Makefile Fragments” in the internals manual. 744 </p> 745 <p>The table below gives the combination of ISAs, architectures, FPUs and 746 floating-point ABIs for which multilibs are built for each predefined 747 profile. The union of these options is considered when specifying both 748 <code>aprofile</code> and <code>rmprofile</code>. 749 </p> 750 <table> 751 <tr><td width="15%">Option</td><td width="28%">aprofile</td><td width="30%">rmprofile</td></tr> 752 <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> 753 <tr><td width="15%">Architectures<br><br><br><br><br><br></td><td width="28%">default architecture<br> 754 <code>-march=armv7-a</code><br> 755 <code>-march=armv7ve</code><br> 756 <code>-march=armv8-a</code><br><br><br></td><td width="30%">default architecture<br> 757 <code>-march=armv6s-m</code><br> 758 <code>-march=armv7-m</code><br> 759 <code>-march=armv7e-m</code><br> 760 <code>-march=armv8-m.base</code><br> 761 <code>-march=armv8-m.main</code><br> 762 <code>-march=armv7</code></td></tr> 763 <tr><td width="15%">FPUs<br><br><br><br><br></td><td width="28%">none<br> 764 <code>-mfpu=vfpv3-d16</code><br> 765 <code>-mfpu=neon</code><br> 766 <code>-mfpu=vfpv4-d16</code><br> 767 <code>-mfpu=neon-vfpv4</code><br> 768 <code>-mfpu=neon-fp-armv8</code></td><td width="30%">none<br> 769 <code>-mfpu=vfpv3-d16</code><br> 770 <code>-mfpu=fpv4-sp-d16</code><br> 771 <code>-mfpu=fpv5-sp-d16</code><br> 772 <code>-mfpu=fpv5-d16</code><br></td></tr> 773 <tr><td width="15%">floating-point ABIs<br><br></td><td width="28%"><code>-mfloat-abi=soft</code><br> 774 <code>-mfloat-abi=softfp</code><br> 775 <code>-mfloat-abi=hard</code></td><td width="30%"><code>-mfloat-abi=soft</code><br> 776 <code>-mfloat-abi=softfp</code><br> 777 <code>-mfloat-abi=hard</code></td></tr> 778 </table> 779 780 </dd> 781 <dt><code>loongarch*-*-*</code></dt> 782 <dd><p><var>list</var> is a comma-separated list, with each of the element starting with 783 the following ABI identifiers: <code>lp64d[/base]</code> <code>lp64f[/base]</code> 784 <code>lp64d[/base]</code> (the <code>/base</code> suffix may be omitted) 785 to enable their respective run-time libraries. 786 </p> 787 <p>A suffix <code>[/<var>arch</var>][/<var>option</var>/…]</code> may follow immediately 788 after the ABI identifier to customize the compiler options for building the 789 given set of libraries. <var>arch</var> denotes the architecture name recognized 790 by the <samp>-march=<var>arch</var></samp> compiler option, which acts as a basic target 791 ISA configuration that can be adjusted using the subsequent <var>option</var> 792 suffixes, where each <var>option</var> is a compiler option without a leading dash 793 (’-’). 794 </p> 795 <p>If no such suffix is present for a given multilib variant, the 796 configured value of <samp>--with-multilib-default</samp> is appended as a default 797 suffix. If <samp>--with-multilib-default</samp> is not given, the default build 798 option <samp>-march=abi-default</samp> is applied when building the variants 799 without a suffix. 800 </p> 801 <p>As a special case, <code>fixed</code> may be used in the position of <var>arch</var>, 802 which means using the architecture configured with 803 <samp>--with-arch=<var>arch</var></samp>, or its default value (e.g. <code>loongarch64</code> 804 for <code>loongarch64-*</code> targets). 805 </p> 806 <p>If <var>list</var> is empty or <code>default</code>, or if <samp>--with-multilib-list</samp> 807 is not specified, then only the default variant of the libraries are built, 808 where the default ABI is implied by the configured target triplet. 809 </p> 810 </dd> 811 <dt><code>riscv*-*-*</code></dt> 812 <dd><p><var>list</var> is a single ABI name. The target architecture must be either 813 <code>rv32gc</code> or <code>rv64gc</code>. This will build a single multilib for the 814 specified architecture and ABI pair. If <code>--with-multilib-list</code> is not 815 given, then a default set of multilibs is selected based on the value of 816 <samp>--target</samp>. This is usually a large set of multilibs. 817 </p> 818 </dd> 819 <dt><code>sh*-*-*</code></dt> 820 <dd><p><var>list</var> is a comma separated list of CPU names. These must be of the 821 form <code>sh*</code> or <code>m*</code> (in which case they match the compiler option 822 for that processor). The list should not contain any endian options - 823 these are handled by <samp>--with-endian</samp>. 824 </p> 825 <p>If <var>list</var> is empty, then there will be no multilibs for extra 826 processors. The multilib for the secondary endian remains enabled. 827 </p> 828 <p>As a special case, if an entry in the list starts with a <code>!</code> 829 (exclamation point), then it is added to the list of excluded multilibs. 830 Entries of this sort should be compatible with ‘<samp>MULTILIB_EXCLUDES</samp>’ 831 (once the leading <code>!</code> has been stripped). 832 </p> 833 <p>If <samp>--with-multilib-list</samp> is not given, then a default set of 834 multilibs is selected based on the value of <samp>--target</samp>. This is 835 usually the complete set of libraries, but some targets imply a more 836 specialized subset. 837 </p> 838 <p>Example 1: to configure a compiler for SH4A only, but supporting both 839 endians, with little endian being the default: 840 </p><div class="smallexample"> 841 <pre class="smallexample">--with-cpu=sh4a --with-endian=little,big --with-multilib-list= 842 </pre></div> 843 844 <p>Example 2: to configure a compiler for both SH4A and SH4AL-DSP, but with 845 only little endian SH4AL: 846 </p><div class="smallexample"> 847 <pre class="smallexample">--with-cpu=sh4a --with-endian=little,big \ 848 --with-multilib-list=sh4al,!mb/m4al 849 </pre></div> 850 851 </dd> 852 <dt><code>x86-64-*-linux*</code></dt> 853 <dd><p><var>list</var> is a comma separated list of <code>m32</code>, <code>m64</code> and 854 <code>mx32</code> to enable 32-bit, 64-bit and x32 run-time libraries, 855 respectively. If <var>list</var> is empty, then there will be no multilibs 856 and only the default run-time library will be enabled. 857 </p> 858 <p>If <samp>--with-multilib-list</samp> is not given, then only 32-bit and 859 64-bit run-time libraries will be enabled. 860 </p></dd> 861 </dl> 862 863 </dd> 864 <dt><code>--with-multilib-default</code></dt> 865 <dd><p>On LoongArch targets, set the default build options for enabled multilibs 866 without build options appended to their corresponding 867 <samp>--with-multilib-list</samp> items. The format of this value is 868 <code>[/<var>arch</var>][/<var>option</var>/…]</code>, where <var>arch</var> is an 869 architecture name recognized by <samp>-march=<var>arch</var></samp> compiler option, 870 and subsequent <var>option</var> suffixes are compiler options minus a leading 871 dash (’-’). 872 </p> 873 <p>Multiple <var>option</var>s may appear consecutively while <var>arch</var> may only 874 appear in the beginning or be omitted (which means <samp>-march=abi-default</samp> 875 is applied when building the libraries). 876 </p> 877 </dd> 878 <dt><code>--with-strict-align-lib</code></dt> 879 <dd><p>On LoongArch targets, build all enabled multilibs with <samp>-mstrict-align</samp> 880 (Not enabled by default). 881 </p> 882 </dd> 883 <dt><code>--with-multilib-generator=<var>config</var></code></dt> 884 <dd><p>Specify what multilibs to build. <var>config</var> is a semicolon separated list of 885 values, possibly consisting of a single value. Currently only implemented 886 for riscv*-*-elf*. The accepted values and meanings are given below. 887 </p> 888 889 <p>Every config is constructed with four components: architecture string, ABI, 890 reuse rule with architecture string and reuse rule with sub-extension. 891 </p> 892 <p>Example 1: Add multi-lib suppport for rv32i with ilp32. 893 </p><div class="smallexample"> 894 <pre class="smallexample">rv32i-ilp32-- 895 </pre></div> 896 897 <p>Example 2: Add multi-lib suppport for rv32i with ilp32 and rv32imafd with ilp32. 898 </p><div class="smallexample"> 899 <pre class="smallexample">rv32i-ilp32--;rv32imafd-ilp32-- 900 </pre></div> 901 902 <p>Example 3: Add multi-lib suppport for rv32i with ilp32; rv32im with ilp32 and 903 rv32ic with ilp32 will reuse this multi-lib set. 904 </p><div class="smallexample"> 905 <pre class="smallexample">rv32i-ilp32-rv32im-c 906 </pre></div> 907 908 <p>Example 4: Add multi-lib suppport for rv64ima with lp64; rv64imaf with lp64, 909 rv64imac with lp64 and rv64imafc with lp64 will reuse this multi-lib set. 910 </p><div class="smallexample"> 911 <pre class="smallexample">rv64ima-lp64--f,c,fc 912 </pre></div> 913 914 <p><samp>--with-multilib-generator</samp> have an optional configuration argument 915 <samp>--cmodel=val</samp> for code model, this option will expand with other 916 config options, <var>val</var> is a comma separated list of possible code model, 917 currently we support medlow and medany. 918 </p> 919 <p>Example 5: Add multi-lib suppport for rv64ima with lp64; rv64ima with lp64 and 920 medlow code model 921 </p><div class="smallexample"> 922 <pre class="smallexample">rv64ima-lp64--;--cmodel=medlow 923 </pre></div> 924 925 <p>Example 6: Add multi-lib suppport for rv64ima with lp64; rv64ima with lp64 and 926 medlow code model; rv64ima with lp64 and medany code model 927 </p><div class="smallexample"> 928 <pre class="smallexample">rv64ima-lp64--;--cmodel=medlow,medany 929 </pre></div> 930 931 </dd> 932 <dt><code>--with-endian=<var>endians</var></code></dt> 933 <dd><p>Specify what endians to use. 934 Currently only implemented for sh*-*-*. 935 </p> 936 <p><var>endians</var> may be one of the following: 937 </p><dl compact="compact"> 938 <dt><code>big</code></dt> 939 <dd><p>Use big endian exclusively. 940 </p></dd> 941 <dt><code>little</code></dt> 942 <dd><p>Use little endian exclusively. 943 </p></dd> 944 <dt><code>big,little</code></dt> 945 <dd><p>Use big endian by default. Provide a multilib for little endian. 946 </p></dd> 947 <dt><code>little,big</code></dt> 948 <dd><p>Use little endian by default. Provide a multilib for big endian. 949 </p></dd> 950 </dl> 951 952 </dd> 953 <dt><code>--enable-threads</code></dt> 954 <dd><p>Specify that the target 955 supports threads. This affects the Objective-C compiler and runtime 956 library, and exception handling for other languages like C++. 957 On some systems, this is the default. 958 </p> 959 <p>In general, the best (and, in many cases, the only known) threading 960 model available will be configured for use. Beware that on some 961 systems, GCC has not been taught what threading models are generally 962 available for the system. In this case, <samp>--enable-threads</samp> is an 963 alias for <samp>--enable-threads=single</samp>. 964 </p> 965 </dd> 966 <dt><code>--disable-threads</code></dt> 967 <dd><p>Specify that threading support should be disabled for the system. 968 This is an alias for <samp>--enable-threads=single</samp>. 969 </p> 970 </dd> 971 <dt><code>--enable-threads=<var>lib</var></code></dt> 972 <dd><p>Specify that 973 <var>lib</var> is the thread support library. This affects the Objective-C 974 compiler and runtime library, and exception handling for other languages 975 like C++. The possibilities for <var>lib</var> are: 976 </p> 977 <dl compact="compact"> 978 <dt><code>aix</code></dt> 979 <dd><p>AIX thread support. 980 </p></dd> 981 <dt><code>dce</code></dt> 982 <dd><p>DCE thread support. 983 </p></dd> 984 <dt><code>lynx</code></dt> 985 <dd><p>LynxOS thread support. 986 </p></dd> 987 <dt><code>mipssde</code></dt> 988 <dd><p>MIPS SDE thread support. 989 </p></dd> 990 <dt><code>no</code></dt> 991 <dd><p>This is an alias for ‘<samp>single</samp>’. 992 </p></dd> 993 <dt><code>posix</code></dt> 994 <dd><p>Generic POSIX/Unix98 thread support. 995 </p></dd> 996 <dt><code>rtems</code></dt> 997 <dd><p>RTEMS thread support. 998 </p></dd> 999 <dt><code>single</code></dt> 1000 <dd><p>Disable thread support, should work for all platforms. 1001 </p></dd> 1002 <dt><code>tpf</code></dt> 1003 <dd><p>TPF thread support. 1004 </p></dd> 1005 <dt><code>vxworks</code></dt> 1006 <dd><p>VxWorks thread support. 1007 </p></dd> 1008 <dt><code>win32</code></dt> 1009 <dd><p>Microsoft Win32 API thread support. 1010 </p></dd> 1011 </dl> 1012 1013 </dd> 1014 <dt><code>--enable-tls</code></dt> 1015 <dd><p>Specify that the target supports TLS (Thread Local Storage). Usually 1016 configure can correctly determine if TLS is supported. In cases where 1017 it guesses incorrectly, TLS can be explicitly enabled or disabled with 1018 <samp>--enable-tls</samp> or <samp>--disable-tls</samp>. This can happen if 1019 the assembler supports TLS but the C library does not, or if the 1020 assumptions made by the configure test are incorrect. 1021 </p> 1022 </dd> 1023 <dt><code>--disable-tls</code></dt> 1024 <dd><p>Specify that the target does not support TLS. 1025 This is an alias for <samp>--enable-tls=no</samp>. 1026 </p> 1027 </dd> 1028 <dt><code>--disable-tm-clone-registry</code></dt> 1029 <dd><p>Disable TM clone registry in libgcc. It is enabled in libgcc by default. 1030 This option helps to reduce code size for embedded targets which do 1031 not use transactional memory. 1032 </p> 1033 </dd> 1034 <dt><code>--with-cpu=<var>cpu</var></code></dt> 1035 <dt><code>--with-cpu-32=<var>cpu</var></code></dt> 1036 <dt><code>--with-cpu-64=<var>cpu</var></code></dt> 1037 <dd><p>Specify which cpu variant the compiler should generate code for by default. 1038 <var>cpu</var> will be used as the default value of the <samp>-mcpu=</samp> switch. 1039 This option is only supported on some targets, including ARC, ARM, i386, M68k, 1040 PowerPC, and SPARC. It is mandatory for ARC. The <samp>--with-cpu-32</samp> and 1041 <samp>--with-cpu-64</samp> options specify separate default CPUs for 1042 32-bit and 64-bit modes; these options are only supported for aarch64, i386, 1043 x86-64, PowerPC, and SPARC. 1044 </p> 1045 </dd> 1046 <dt><code>--with-schedule=<var>cpu</var></code></dt> 1047 <dt><code>--with-arch=<var>cpu</var></code></dt> 1048 <dt><code>--with-arch-32=<var>cpu</var></code></dt> 1049 <dt><code>--with-arch-64=<var>cpu</var></code></dt> 1050 <dt><code>--with-tune=<var>cpu</var></code></dt> 1051 <dt><code>--with-tune-32=<var>cpu</var></code></dt> 1052 <dt><code>--with-tune-64=<var>cpu</var></code></dt> 1053 <dt><code>--with-abi=<var>abi</var></code></dt> 1054 <dt><code>--with-fpu=<var>type</var></code></dt> 1055 <dt><code>--with-float=<var>type</var></code></dt> 1056 <dt><code>--with-simd=<var>type</var></code></dt> 1057 <dd><p>These configure options provide default values for the <samp>-mschedule=</samp>, 1058 <samp>-march=</samp>, <samp>-mtune=</samp>, <samp>-mabi=</samp>, and <samp>-mfpu=</samp> 1059 options and for <samp>-mhard-float</samp> or <samp>-msoft-float</samp>. As with 1060 <samp>--with-cpu</samp>, which switches will be accepted and acceptable values 1061 of the arguments depend on the target. 1062 </p> 1063 </dd> 1064 <dt><code>--with-mode=<var>mode</var></code></dt> 1065 <dd><p>Specify if the compiler should default to <samp>-marm</samp> or <samp>-mthumb</samp>. 1066 This option is only supported on ARM targets. 1067 </p> 1068 </dd> 1069 <dt><code>--with-stack-offset=<var>num</var></code></dt> 1070 <dd><p>This option sets the default for the -mstack-offset=<var>num</var> option, 1071 and will thus generally also control the setting of this option for 1072 libraries. This option is only supported on Epiphany targets. 1073 </p> 1074 </dd> 1075 <dt><code>--with-fpmath=<var>isa</var></code></dt> 1076 <dd><p>This options sets <samp>-mfpmath=sse</samp> by default and specifies the default 1077 ISA for floating-point arithmetics. You can select either ‘<samp>sse</samp>’ which 1078 enables <samp>-msse2</samp> or ‘<samp>avx</samp>’ which enables <samp>-mavx</samp> by default. 1079 This option is only supported on i386 and x86-64 targets. 1080 </p> 1081 </dd> 1082 <dt><code>--with-fp-32=<var>mode</var></code></dt> 1083 <dd><p>On MIPS targets, set the default value for the <samp>-mfp</samp> option when using 1084 the o32 ABI. The possibilities for <var>mode</var> are: 1085 </p><dl compact="compact"> 1086 <dt><code>32</code></dt> 1087 <dd><p>Use the o32 FP32 ABI extension, as with the <samp>-mfp32</samp> command-line 1088 option. 1089 </p></dd> 1090 <dt><code>xx</code></dt> 1091 <dd><p>Use the o32 FPXX ABI extension, as with the <samp>-mfpxx</samp> command-line 1092 option. 1093 </p></dd> 1094 <dt><code>64</code></dt> 1095 <dd><p>Use the o32 FP64 ABI extension, as with the <samp>-mfp64</samp> command-line 1096 option. 1097 </p></dd> 1098 </dl> 1099 <p>In the absence of this configuration option the default is to use the o32 1100 FP32 ABI extension. 1101 </p> 1102 </dd> 1103 <dt><code>--with-odd-spreg-32</code></dt> 1104 <dd><p>On MIPS targets, set the <samp>-modd-spreg</samp> option by default when using 1105 the o32 ABI. 1106 </p> 1107 </dd> 1108 <dt><code>--without-odd-spreg-32</code></dt> 1109 <dd><p>On MIPS targets, set the <samp>-mno-odd-spreg</samp> option by default when using 1110 the o32 ABI. This is normally used in conjunction with 1111 <samp>--with-fp-32=64</samp> in order to target the o32 FP64A ABI extension. 1112 </p> 1113 </dd> 1114 <dt><code>--with-nan=<var>encoding</var></code></dt> 1115 <dd><p>On MIPS targets, set the default encoding convention to use for the 1116 special not-a-number (NaN) IEEE 754 floating-point data. The 1117 possibilities for <var>encoding</var> are: 1118 </p><dl compact="compact"> 1119 <dt><code>legacy</code></dt> 1120 <dd><p>Use the legacy encoding, as with the <samp>-mnan=legacy</samp> command-line 1121 option. 1122 </p></dd> 1123 <dt><code>2008</code></dt> 1124 <dd><p>Use the 754-2008 encoding, as with the <samp>-mnan=2008</samp> command-line 1125 option. 1126 </p></dd> 1127 </dl> 1128 <p>To use this configuration option you must have an assembler version 1129 installed that supports the <samp>-mnan=</samp> command-line option too. 1130 In the absence of this configuration option the default convention is 1131 the legacy encoding, as when neither of the <samp>-mnan=2008</samp> and 1132 <samp>-mnan=legacy</samp> command-line options has been used. 1133 </p> 1134 </dd> 1135 <dt><code>--with-divide=<var>type</var></code></dt> 1136 <dd><p>Specify how the compiler should generate code for checking for 1137 division by zero. This option is only supported on the MIPS target. 1138 The possibilities for <var>type</var> are: 1139 </p><dl compact="compact"> 1140 <dt><code>traps</code></dt> 1141 <dd><p>Division by zero checks use conditional traps (this is the default on 1142 systems that support conditional traps). 1143 </p></dd> 1144 <dt><code>breaks</code></dt> 1145 <dd><p>Division by zero checks use the break instruction. 1146 </p></dd> 1147 </dl> 1148 1149 </dd> 1150 <dt><code>--with-compact-branches=<var>policy</var></code></dt> 1151 <dd><p>Specify how the compiler should generate branch instructions. 1152 This option is only supported on the MIPS target. 1153 The possibilities for <var>type</var> are: 1154 </p><dl compact="compact"> 1155 <dt><code>optimal</code></dt> 1156 <dd><p>Cause a delay slot branch to be used if one is available in the 1157 current ISA and the delay slot is successfully filled. If the delay slot 1158 is not filled, a compact branch will be chosen if one is available. 1159 </p></dd> 1160 <dt><code>never</code></dt> 1161 <dd><p>Ensures that compact branch instructions will never be generated. 1162 </p></dd> 1163 <dt><code>always</code></dt> 1164 <dd><p>Ensures that a compact branch instruction will be generated if available. 1165 If a compact branch instruction is not available, 1166 a delay slot form of the branch will be used instead. 1167 This option is supported from MIPS Release 6 onwards. 1168 For pre-R6/microMIPS/MIPS16, this option is just same as never/optimal. 1169 </p></dd> 1170 </dl> 1171 1172 1173 </dd> 1174 <dt><code>--with-llsc</code></dt> 1175 <dd><p>On MIPS targets, make <samp>-mllsc</samp> the default when no 1176 <samp>-mno-llsc</samp> option is passed. This is the default for 1177 Linux-based targets, as the kernel will emulate them if the ISA does 1178 not provide them. 1179 </p> 1180 </dd> 1181 <dt><code>--without-llsc</code></dt> 1182 <dd><p>On MIPS targets, make <samp>-mno-llsc</samp> the default when no 1183 <samp>-mllsc</samp> option is passed. 1184 </p> 1185 </dd> 1186 <dt><code>--with-synci</code></dt> 1187 <dd><p>On MIPS targets, make <samp>-msynci</samp> the default when no 1188 <samp>-mno-synci</samp> option is passed. 1189 </p> 1190 </dd> 1191 <dt><code>--without-synci</code></dt> 1192 <dd><p>On MIPS targets, make <samp>-mno-synci</samp> the default when no 1193 <samp>-msynci</samp> option is passed. This is the default. 1194 </p> 1195 </dd> 1196 <dt><code>--with-lxc1-sxc1</code></dt> 1197 <dd><p>On MIPS targets, make <samp>-mlxc1-sxc1</samp> the default when no 1198 <samp>-mno-lxc1-sxc1</samp> option is passed. This is the default. 1199 </p> 1200 </dd> 1201 <dt><code>--without-lxc1-sxc1</code></dt> 1202 <dd><p>On MIPS targets, make <samp>-mno-lxc1-sxc1</samp> the default when no 1203 <samp>-mlxc1-sxc1</samp> option is passed. The indexed load/store 1204 instructions are not directly a problem but can lead to unexpected 1205 behaviour when deployed in an application intended for a 32-bit address 1206 space but run on a 64-bit processor. The issue is seen because all 1207 known MIPS 64-bit Linux kernels execute o32 and n32 applications 1208 with 64-bit addressing enabled which affects the overflow behaviour 1209 of the indexed addressing mode. GCC will assume that ordinary 1210 32-bit arithmetic overflow behaviour is the same whether performed 1211 as an <code>addu</code> instruction or as part of the address calculation 1212 in <code>lwxc1</code> type instructions. This assumption holds true in a 1213 pure 32-bit environment and can hold true in a 64-bit environment if 1214 the address space is accurately set to be 32-bit for o32 and n32. 1215 </p> 1216 </dd> 1217 <dt><code>--with-madd4</code></dt> 1218 <dd><p>On MIPS targets, make <samp>-mmadd4</samp> the default when no 1219 <samp>-mno-madd4</samp> option is passed. This is the default. 1220 </p> 1221 </dd> 1222 <dt><code>--without-madd4</code></dt> 1223 <dd><p>On MIPS targets, make <samp>-mno-madd4</samp> the default when no 1224 <samp>-mmadd4</samp> option is passed. The <code>madd4</code> instruction 1225 family can be problematic when targeting a combination of cores that 1226 implement these instructions differently. There are two known cores 1227 that implement these as fused operations instead of unfused (where 1228 unfused is normally expected). Disabling these instructions is the 1229 only way to ensure compatible code is generated; this will incur 1230 a performance penalty. 1231 </p> 1232 </dd> 1233 <dt><code>--with-msa</code></dt> 1234 <dd><p>On MIPS targets, make <samp>-mmsa</samp> the default when no 1235 <samp>-mno-msa</samp> option is passed. 1236 </p> 1237 </dd> 1238 <dt><code>--without-msa</code></dt> 1239 <dd><p>On MIPS targets, make <samp>-mno-msa</samp> the default when no 1240 <samp>-mmsa</samp> option is passed. This is the default. 1241 </p> 1242 </dd> 1243 <dt><code>--with-mips-plt</code></dt> 1244 <dd><p>On MIPS targets, make use of copy relocations and PLTs. 1245 These features are extensions to the traditional 1246 SVR4-based MIPS ABIs and require support from GNU binutils 1247 and the runtime C library. 1248 </p> 1249 </dd> 1250 <dt><code>--with-stack-clash-protection-guard-size=<var>size</var></code></dt> 1251 <dd><p>On certain targets this option sets the default stack clash protection guard 1252 size as a power of two in bytes. On AArch64 <var>size</var> is required to be either 1253 12 (4KB) or 16 (64KB). 1254 </p> 1255 </dd> 1256 <dt><code>--with-isa-spec=<var>ISA-spec-string</var></code></dt> 1257 <dd><p>On RISC-V targets specify the default version of the RISC-V Unprivileged 1258 (formerly User-Level) ISA specification to produce code conforming to. 1259 The possibilities for <var>ISA-spec-string</var> are: 1260 </p><dl compact="compact"> 1261 <dt><code>2.2</code></dt> 1262 <dd><p>Produce code conforming to version 2.2. 1263 </p></dd> 1264 <dt><code>20190608</code></dt> 1265 <dd><p>Produce code conforming to version 20190608. 1266 </p></dd> 1267 <dt><code>20191213</code></dt> 1268 <dd><p>Produce code conforming to version 20191213. 1269 </p></dd> 1270 </dl> 1271 <p>In the absence of this configuration option the default version is 20191213. 1272 </p> 1273 </dd> 1274 <dt><code>--enable-__cxa_atexit</code></dt> 1275 <dd><p>Define if you want to use __cxa_atexit, rather than atexit, to 1276 register C++ destructors for local statics and global objects. 1277 This is essential for fully standards-compliant handling of 1278 destructors, but requires __cxa_atexit in libc. This option is currently 1279 only available on systems with GNU libc. When enabled, this will cause 1280 <samp>-fuse-cxa-atexit</samp> to be passed by default. 1281 </p> 1282 </dd> 1283 <dt><code>--enable-gnu-indirect-function</code></dt> 1284 <dd><p>Define if you want to enable the <code>ifunc</code> attribute. This option is 1285 currently only available on systems with GNU libc on certain targets. 1286 </p> 1287 </dd> 1288 <dt><code>--enable-target-optspace</code></dt> 1289 <dd><p>Specify that target 1290 libraries should be optimized for code space instead of code speed. 1291 This is the default for the m32r platform. 1292 </p> 1293 </dd> 1294 <dt><code>--with-cpp-install-dir=<var>dirname</var></code></dt> 1295 <dd><p>Specify that the user visible <code>cpp</code> program should be installed 1296 in <samp><var>prefix</var>/<var>dirname</var>/cpp</samp>, in addition to <var>bindir</var>. 1297 </p> 1298 </dd> 1299 <dt><code>--enable-comdat</code></dt> 1300 <dd><p>Enable COMDAT group support. This is primarily used to override the 1301 automatically detected value. 1302 </p> 1303 </dd> 1304 <dt><code>--enable-initfini-array</code></dt> 1305 <dd><p>Force the use of sections <code>.init_array</code> and <code>.fini_array</code> 1306 (instead of <code>.init</code> and <code>.fini</code>) for constructors and 1307 destructors. Option <samp>--disable-initfini-array</samp> has the 1308 opposite effect. If neither option is specified, the configure script 1309 will try to guess whether the <code>.init_array</code> and 1310 <code>.fini_array</code> sections are supported and, if they are, use them. 1311 </p> 1312 </dd> 1313 <dt><code>--enable-link-mutex</code></dt> 1314 <dd><p>When building GCC, use a mutex to avoid linking the compilers for 1315 multiple languages at the same time, to avoid thrashing on build 1316 systems with limited free memory. The default is not to use such a mutex. 1317 </p> 1318 </dd> 1319 <dt><code>--enable-link-serialization</code></dt> 1320 <dd><p>When building GCC, use make dependencies to serialize linking the compilers for 1321 multiple languages, to avoid thrashing on build 1322 systems with limited free memory. The default is not to add such 1323 dependencies and thus with parallel make potentially link different 1324 compilers concurrently. If the argument is a positive integer, allow 1325 that number of concurrent link processes for the large binaries. 1326 </p> 1327 </dd> 1328 <dt><code>--enable-maintainer-mode</code></dt> 1329 <dd><p>The build rules that regenerate the Autoconf and Automake output files as 1330 well as the GCC master message catalog <samp>gcc.pot</samp> are normally 1331 disabled. This is because it can only be rebuilt if the complete source 1332 tree is present. If you have changed the sources and want to rebuild the 1333 catalog, configuring with <samp>--enable-maintainer-mode</samp> will enable 1334 this. Note that you need a recent version of the <code>gettext</code> tools 1335 to do so. 1336 </p> 1337 </dd> 1338 <dt><code>--disable-bootstrap</code></dt> 1339 <dd><p>For a native build, the default configuration is to perform 1340 a 3-stage bootstrap of the compiler when ‘<samp>make</samp>’ is invoked, 1341 testing that GCC can compile itself correctly. If you want to disable 1342 this process, you can configure with <samp>--disable-bootstrap</samp>. 1343 </p> 1344 </dd> 1345 <dt><code>--enable-bootstrap</code></dt> 1346 <dd><p>In special cases, you may want to perform a 3-stage build 1347 even if the target and host triplets are different. 1348 This is possible when the host can run code compiled for 1349 the target (e.g. host is i686-linux, target is i486-linux). 1350 Starting from GCC 4.2, to do this you have to configure explicitly 1351 with <samp>--enable-bootstrap</samp>. 1352 </p> 1353 </dd> 1354 <dt><code>--enable-generated-files-in-srcdir</code></dt> 1355 <dd><p>Neither the .c and .h files that are generated from Bison and flex nor the 1356 info manuals and man pages that are built from the .texi files are present 1357 in the repository development tree. When building GCC from that development tree, 1358 or from one of our snapshots, those generated files are placed in your 1359 build directory, which allows for the source to be in a readonly 1360 directory. 1361 </p> 1362 <p>If you configure with <samp>--enable-generated-files-in-srcdir</samp> then those 1363 generated files will go into the source directory. This is mainly intended 1364 for generating release or prerelease tarballs of the GCC sources, since it 1365 is not a requirement that the users of source releases to have flex, Bison, 1366 or makeinfo. 1367 </p> 1368 </dd> 1369 <dt><code>--enable-version-specific-runtime-libs</code></dt> 1370 <dd><p>Specify 1371 that runtime libraries should be installed in the compiler specific 1372 subdirectory (<samp><var>libdir</var>/gcc</samp>) rather than the usual places. In 1373 addition, ‘<samp>libstdc++</samp>’’s include files will be installed into 1374 <samp><var>libdir</var></samp> unless you overruled it by using 1375 <samp>--with-gxx-include-dir=<var>dirname</var></samp>. Using this option is 1376 particularly useful if you intend to use several versions of GCC in 1377 parallel. The default is ‘<samp>yes</samp>’ for ‘<samp>libada</samp>’, and ‘<samp>no</samp>’ for 1378 the remaining libraries. 1379 </p> 1380 </dd> 1381 <dt><code>--with-darwin-extra-rpath</code></dt> 1382 <dd><p>This is provided to allow distributions to add a single additional 1383 runpath on Darwin / macOS systems. This allows for cases where the 1384 installed GCC library directories are then symlinked to a common 1385 directory outside of the GCC installation. 1386 </p> 1387 </dd> 1388 <dt><code><a name="WithAixSoname"></a>--with-aix-soname=‘<samp>aix</samp>’, ‘<samp>svr4</samp>’ or ‘<samp>both</samp>’</code></dt> 1389 <dd><p>Traditional AIX shared library versioning (versioned <code>Shared Object</code> 1390 files as members of unversioned <code>Archive Library</code> files named 1391 ‘<samp>lib.a</samp>’) causes numerous headaches for package managers. However, 1392 <code>Import Files</code> as members of <code>Archive Library</code> files allow for 1393 <strong>filename-based versioning</strong> of shared libraries as seen on Linux/SVR4, 1394 where this is called the "SONAME". But as they prevent static linking, 1395 <code>Import Files</code> may be used with <code>Runtime Linking</code> only, where the 1396 linker does search for ‘<samp>libNAME.so</samp>’ before ‘<samp>libNAME.a</samp>’ library 1397 filenames with the ‘<samp>-lNAME</samp>’ linker flag. 1398 </p> 1399 <a name="AixLdCommand"></a><p>For detailed information please refer to the AIX 1400 <a href="https://www.ibm.com/support/knowledgecenter/search/%22the%20ld%20command%2C%20also%20called%20the%20linkage%20editor%20or%20binder%22">ld 1401 Command</a> reference. 1402 </p> 1403 <p>As long as shared library creation is enabled, upon: 1404 </p><dl compact="compact"> 1405 <dt><code>--with-aix-soname=aix</code></dt> 1406 <dt><code>--with-aix-soname=both</code></dt> 1407 <dd><p>A (traditional AIX) <code>Shared Archive Library</code> file is created: 1408 </p><ul> 1409 <li> using the ‘<samp>libNAME.a</samp>’ filename scheme 1410 </li><li> with the <code>Shared Object</code> file as archive member named 1411 ‘<samp>libNAME.so.V</samp>’ (except for ‘<samp>libgcc_s</samp>’, where the <code>Shared 1412 Object</code> file is named ‘<samp>shr.o</samp>’ for backwards compatibility), which 1413 <ul class="no-bullet"> 1414 <li>- is used for runtime loading from inside the ‘<samp>libNAME.a</samp>’ file 1415 </li><li>- is used for dynamic loading via 1416 <code>dlopen("libNAME.a(libNAME.so.V)", RTLD_MEMBER)</code> 1417 </li><li>- is used for shared linking 1418 </li><li>- is used for static linking, so no separate <code>Static Archive 1419 Library</code> file is needed 1420 </li></ul> 1421 </li></ul> 1422 </dd> 1423 <dt><code>--with-aix-soname=both</code></dt> 1424 <dt><code>--with-aix-soname=svr4</code></dt> 1425 <dd><p>A (second) <code>Shared Archive Library</code> file is created: 1426 </p><ul> 1427 <li> using the ‘<samp>libNAME.so.V</samp>’ filename scheme 1428 </li><li> with the <code>Shared Object</code> file as archive member named 1429 ‘<samp>shr.o</samp>’, which 1430 <ul class="no-bullet"> 1431 <li>- is created with the <code>-G linker flag</code> 1432 </li><li>- has the <code>F_LOADONLY</code> flag set 1433 </li><li>- is used for runtime loading from inside the ‘<samp>libNAME.so.V</samp>’ file 1434 </li><li>- is used for dynamic loading via <code>dlopen("libNAME.so.V(shr.o)", 1435 RTLD_MEMBER)</code> 1436 </li></ul> 1437 </li><li> with the <code>Import File</code> as archive member named ‘<samp>shr.imp</samp>’, 1438 which 1439 <ul class="no-bullet"> 1440 <li>- refers to ‘<samp>libNAME.so.V(shr.o)</samp>’ as the "SONAME", to be recorded 1441 in the <code>Loader Section</code> of subsequent binaries 1442 </li><li>- indicates whether ‘<samp>libNAME.so.V(shr.o)</samp>’ is 32 or 64 bit 1443 </li><li>- lists all the public symbols exported by ‘<samp>lib.so.V(shr.o)</samp>’, 1444 eventually decorated with the <code>‘<samp>weak</samp>’ Keyword</code> 1445 </li><li>- is necessary for shared linking against ‘<samp>lib.so.V(shr.o)</samp>’ 1446 </li></ul> 1447 </li></ul> 1448 <p>A symbolic link using the ‘<samp>libNAME.so</samp>’ filename scheme is created: 1449 </p><ul> 1450 <li> pointing to the ‘<samp>libNAME.so.V</samp>’ <code>Shared Archive Library</code> file 1451 </li><li> to permit the <code>ld Command</code> to find ‘<samp>lib.so.V(shr.imp)</samp>’ via 1452 the ‘<samp>-lNAME</samp>’ argument (requires <code>Runtime Linking</code> to be enabled) 1453 </li><li> to permit dynamic loading of ‘<samp>lib.so.V(shr.o)</samp>’ without the need 1454 to specify the version number via <code>dlopen("libNAME.so(shr.o)", 1455 RTLD_MEMBER)</code> 1456 </li></ul> 1457 </dd> 1458 </dl> 1459 1460 <p>As long as static library creation is enabled, upon: 1461 </p><dl compact="compact"> 1462 <dt><code>--with-aix-soname=svr4</code></dt> 1463 <dd><p>A <code>Static Archive Library</code> is created: 1464 </p><ul> 1465 <li> using the ‘<samp>libNAME.a</samp>’ filename scheme 1466 </li><li> with all the <code>Static Object</code> files as archive members, which 1467 <ul class="no-bullet"> 1468 <li>- are used for static linking 1469 </li></ul> 1470 </li></ul> 1471 </dd> 1472 </dl> 1473 1474 <p>While the aix-soname=‘<samp>svr4</samp>’ option does not create <code>Shared Object</code> 1475 files as members of unversioned <code>Archive Library</code> files any more, package 1476 managers still are responsible to 1477 <a href="./specific.html#TransferAixShobj">transfer</a> <code>Shared Object</code> files 1478 found as member of a previously installed unversioned <code>Archive Library</code> 1479 file into the newly installed <code>Archive Library</code> file with the same 1480 filename. 1481 </p> 1482 <p><em>WARNING:</em> Creating <code>Shared Object</code> files with <code>Runtime Linking</code> 1483 enabled may bloat the TOC, eventually leading to <code>TOC overflow</code> errors, 1484 requiring the use of either the <samp>-Wl,-bbigtoc</samp> linker flag (seen to 1485 break with the <code>GDB</code> debugger) or some of the TOC-related compiler flags, 1486 see “RS/6000 and PowerPC Options” in the main manual. 1487 </p> 1488 <p><samp>--with-aix-soname</samp> is currently supported by ‘<samp>libgcc_s</samp>’ only, so 1489 this option is still experimental and not for normal use yet. 1490 </p> 1491 <p>Default is the traditional behavior <samp>--with-aix-soname=‘<samp>aix</samp>’</samp>. 1492 </p> 1493 </dd> 1494 <dt><code>--enable-languages=<var>lang1</var>,<var>lang2</var>,…</code></dt> 1495 <dd><p>Specify that only a particular subset of compilers and 1496 their runtime libraries should be built. For a list of valid values for 1497 <var>langN</var> you can issue the following command in the 1498 <samp>gcc</samp> directory of your GCC source tree:<br> 1499 </p><div class="smallexample"> 1500 <pre class="smallexample">grep ^language= */config-lang.in 1501 </pre></div> 1502 <p>Currently, you can use any of the following: 1503 <code>all</code>, <code>default</code>, <code>ada</code>, <code>c</code>, <code>c++</code>, <code>d</code>, 1504 <code>fortran</code>, <code>go</code>, <code>jit</code>, <code>lto</code>, <code>m2</code>, 1505 <code>objc</code>, <code>obj-c++</code>. 1506 Building the Ada compiler has special requirements, see below. 1507 If you do not pass this flag, or specify the option <code>default</code>, then the 1508 default languages available in the <samp>gcc</samp> sub-tree will be configured. 1509 Ada, D, Go, Jit, Objective-C++ and Modula-2 are not default languages. 1510 LTO is not a 1511 default language, but is built by default because <samp>--enable-lto</samp> is 1512 enabled by default. The other languages are default languages. If 1513 <code>all</code> is specified, then all available languages are built. An 1514 exception is <code>jit</code> language, which requires 1515 <samp>--enable-host-shared</samp> to be included with <code>all</code>. 1516 </p> 1517 </dd> 1518 <dt><code>--enable-stage1-languages=<var>lang1</var>,<var>lang2</var>,…</code></dt> 1519 <dd><p>Specify that a particular subset of compilers and their runtime 1520 libraries should be built with the system C compiler during stage 1 of 1521 the bootstrap process, rather than only in later stages with the 1522 bootstrapped C compiler. The list of valid values is the same as for 1523 <samp>--enable-languages</samp>, and the option <code>all</code> will select all 1524 of the languages enabled by <samp>--enable-languages</samp>. This option is 1525 primarily useful for GCC development; for instance, when a development 1526 version of the compiler cannot bootstrap due to compiler bugs, or when 1527 one is debugging front ends other than the C front end. When this 1528 option is used, one can then build the target libraries for the 1529 specified languages with the stage-1 compiler by using <code>make 1530 stage1-bubble all-target</code>, or run the testsuite on the stage-1 compiler 1531 for the specified languages using <code>make stage1-start check-gcc</code>. 1532 </p> 1533 </dd> 1534 <dt><code>--disable-libada</code></dt> 1535 <dd><p>Specify that the run-time libraries and tools used by GNAT should not 1536 be built. This can be useful for debugging, or for compatibility with 1537 previous Ada build procedures, when it was required to explicitly 1538 do a ‘<samp>make -C gcc gnatlib_and_tools</samp>’. 1539 </p> 1540 </dd> 1541 <dt><code>--disable-libgm2</code></dt> 1542 <dd><p>Specify that the run-time libraries and tools used by Modula-2 should not 1543 be built. This can be useful for debugging. 1544 </p> 1545 </dd> 1546 <dt><code>--disable-libsanitizer</code></dt> 1547 <dd><p>Specify that the run-time libraries for the various sanitizers should 1548 not be built. 1549 </p> 1550 </dd> 1551 <dt><code>--disable-libssp</code></dt> 1552 <dd><p>Specify that the run-time libraries for stack smashing protection 1553 should not be built or linked against. On many targets library support 1554 is provided by the C library instead. 1555 </p> 1556 </dd> 1557 <dt><code>--disable-libquadmath</code></dt> 1558 <dd><p>Specify that the GCC quad-precision math library should not be built. 1559 On some systems, the library is required to be linkable when building 1560 the Fortran front end, unless <samp>--disable-libquadmath-support</samp> 1561 is used. 1562 </p> 1563 </dd> 1564 <dt><code>--disable-libquadmath-support</code></dt> 1565 <dd><p>Specify that the Fortran front end and <code>libgfortran</code> do not add 1566 support for <code>libquadmath</code> on systems supporting it. 1567 </p> 1568 </dd> 1569 <dt><code>--disable-libgomp</code></dt> 1570 <dd><p>Specify that the GNU Offloading and Multi Processing Runtime Library 1571 should not be built. 1572 </p> 1573 </dd> 1574 <dt><code>--disable-libvtv</code></dt> 1575 <dd><p>Specify that the run-time libraries used by vtable verification 1576 should not be built. 1577 </p> 1578 </dd> 1579 <dt><code>--with-dwarf2</code></dt> 1580 <dd><p>Specify that the compiler should 1581 use DWARF debugging information as the default; the exact 1582 DWARF version that is the default is target-specific. 1583 </p> 1584 </dd> 1585 <dt><code>--with-advance-toolchain=<var>at</var></code></dt> 1586 <dd><p>On 64-bit PowerPC Linux systems, configure the compiler to use the 1587 header files, library files, and the dynamic linker from the Advance 1588 Toolchain release <var>at</var> instead of the default versions that are 1589 provided by the Linux distribution. In general, this option is 1590 intended for the developers of GCC, and it is not intended for general 1591 use. 1592 </p> 1593 </dd> 1594 <dt><code>--enable-targets=all</code></dt> 1595 <dt><code>--enable-targets=<var>target_list</var></code></dt> 1596 <dd><p>Some GCC targets, e.g. powerpc64-linux, build bi-arch compilers. 1597 These are compilers that are able to generate either 64-bit or 32-bit 1598 code. Typically, the corresponding 32-bit target, e.g. 1599 powerpc-linux for powerpc64-linux, only generates 32-bit code. This 1600 option enables the 32-bit target to be a bi-arch compiler, which is 1601 useful when you want a bi-arch compiler that defaults to 32-bit, and 1602 you are building a bi-arch or multi-arch binutils in a combined tree. 1603 On mips-linux, this will build a tri-arch compiler (ABI o32/n32/64), 1604 defaulted to o32. 1605 Currently, this option only affects sparc-linux, powerpc-linux, x86-linux, 1606 mips-linux and s390-linux. 1607 </p> 1608 </dd> 1609 <dt><code>--enable-default-pie</code></dt> 1610 <dd><p>Turn on <samp>-fPIE</samp> and <samp>-pie</samp> by default. 1611 </p> 1612 </dd> 1613 <dt><code>--enable-secureplt</code></dt> 1614 <dd><p>This option enables <samp>-msecure-plt</samp> by default for powerpc-linux. 1615 See “RS/6000 and PowerPC Options” in the main manual 1616 </p> 1617 </dd> 1618 <dt><code>--enable-default-ssp</code></dt> 1619 <dd><p>Turn on <samp>-fstack-protector-strong</samp> by default. 1620 </p> 1621 </dd> 1622 <dt><code>--enable-cld</code></dt> 1623 <dd><p>This option enables <samp>-mcld</samp> by default for 32-bit x86 targets. 1624 See “i386 and x86-64 Options” in the main manual 1625 </p> 1626 </dd> 1627 <dt><code>--enable-large-address-aware</code></dt> 1628 <dd><p>The <samp>--enable-large-address-aware</samp> option arranges for MinGW 1629 executables to be linked using the <samp>--large-address-aware</samp> 1630 option, that enables the use of more than 2GB of memory. If GCC is 1631 configured with this option, its effects can be reversed by passing the 1632 <samp>-Wl,--disable-large-address-aware</samp> option to the so-configured 1633 compiler driver. 1634 </p> 1635 </dd> 1636 <dt><code>--enable-win32-registry</code></dt> 1637 <dt><code>--enable-win32-registry=<var>key</var></code></dt> 1638 <dt><code>--disable-win32-registry</code></dt> 1639 <dd><p>The <samp>--enable-win32-registry</samp> option enables Microsoft Windows-hosted GCC 1640 to look up installations paths in the registry using the following key: 1641 </p> 1642 <div class="smallexample"> 1643 <pre class="smallexample"><code>HKEY_LOCAL_MACHINE\SOFTWARE\Free Software Foundation\<var>key</var></code> 1644 </pre></div> 1645 1646 <p><var>key</var> defaults to GCC version number, and can be overridden by the 1647 <samp>--enable-win32-registry=<var>key</var></samp> option. Vendors and distributors 1648 who use custom installers are encouraged to provide a different key, 1649 perhaps one comprised of vendor name and GCC version number, to 1650 avoid conflict with existing installations. This feature is enabled 1651 by default, and can be disabled by <samp>--disable-win32-registry</samp> 1652 option. This option has no effect on the other hosts. 1653 </p> 1654 </dd> 1655 <dt><code>--nfp</code></dt> 1656 <dd><p>Specify that the machine does not have a floating point unit. This 1657 option only applies to ‘<samp>m68k-sun-sunos<var>n</var></samp>’. On any other 1658 system, <samp>--nfp</samp> has no effect. 1659 </p> 1660 </dd> 1661 <dt><code>--enable-werror</code></dt> 1662 <dt><code>--disable-werror</code></dt> 1663 <dt><code>--enable-werror=yes</code></dt> 1664 <dt><code>--enable-werror=no</code></dt> 1665 <dd><p>When you specify this option, it controls whether certain files in the 1666 compiler are built with <samp>-Werror</samp> in bootstrap stage2 and later. 1667 If you don’t specify it, <samp>-Werror</samp> is turned on for the main 1668 development trunk. However it defaults to off for release branches and 1669 final releases. The specific files which get <samp>-Werror</samp> are 1670 controlled by the Makefiles. 1671 </p> 1672 </dd> 1673 <dt><code>--enable-checking</code></dt> 1674 <dt><code>--disable-checking</code></dt> 1675 <dt><code>--enable-checking=<var>list</var></code></dt> 1676 <dd><p>This option controls performing internal consistency checks in the compiler. 1677 It does not change the generated code, but adds error checking of the 1678 requested complexity. This slows down the compiler and may only work 1679 properly if you are building the compiler with GCC. 1680 </p> 1681 <p>When the option is not specified, the active set of checks depends on context. 1682 Namely, bootstrap stage 1 defaults to ‘<samp>--enable-checking=yes</samp>’, builds 1683 from release branches or release archives default to 1684 ‘<samp>--enable-checking=release</samp>’, and otherwise 1685 ‘<samp>--enable-checking=yes,extra</samp>’ is used. When the option is 1686 specified without a <var>list</var>, the result is the same as 1687 ‘<samp>--enable-checking=yes</samp>’. Likewise, ‘<samp>--disable-checking</samp>’ is 1688 equivalent to ‘<samp>--enable-checking=no</samp>’. 1689 </p> 1690 <p>The categories of checks available in <var>list</var> are ‘<samp>yes</samp>’ (most common 1691 checks ‘<samp>assert,misc,gc,gimple,rtlflag,runtime,tree,types</samp>’), ‘<samp>no</samp>’ 1692 (no checks at all), ‘<samp>all</samp>’ (all but ‘<samp>valgrind</samp>’), ‘<samp>release</samp>’ 1693 (cheapest checks ‘<samp>assert,runtime</samp>’) or ‘<samp>none</samp>’ (same as ‘<samp>no</samp>’). 1694 ‘<samp>release</samp>’ checks are always on and to disable them 1695 ‘<samp>--disable-checking</samp>’ or ‘<samp>--enable-checking=no[,<other checks>]</samp>’ 1696 must be explicitly requested. Disabling assertions makes the compiler and 1697 runtime slightly faster but increases the risk of undetected internal errors 1698 causing wrong code to be generated. 1699 </p> 1700 <p>Individual checks can be enabled with these flags: ‘<samp>assert</samp>’, ‘<samp>df</samp>’, 1701 ‘<samp>extra</samp>’, ‘<samp>fold</samp>’, ‘<samp>gc</samp>’, ‘<samp>gcac</samp>’, ‘<samp>gimple</samp>’, 1702 ‘<samp>misc</samp>’, ‘<samp>rtl</samp>’, ‘<samp>rtlflag</samp>’, ‘<samp>runtime</samp>’, ‘<samp>tree</samp>’, 1703 ‘<samp>types</samp>’ and ‘<samp>valgrind</samp>’. ‘<samp>extra</samp>’ extends ‘<samp>misc</samp>’ 1704 checking with extra checks that might affect code generation and should 1705 therefore not differ between stage1 and later stages in bootstrap. 1706 </p> 1707 <p>The ‘<samp>valgrind</samp>’ check requires the external <code>valgrind</code> simulator, 1708 available from <a href="https://valgrind.org">https://valgrind.org</a>. The ‘<samp>rtl</samp>’ checks are 1709 expensive and the ‘<samp>df</samp>’, ‘<samp>gcac</samp>’ and ‘<samp>valgrind</samp>’ checks are very 1710 expensive. 1711 </p> 1712 </dd> 1713 <dt><code>--disable-stage1-checking</code></dt> 1714 <dt><code>--enable-stage1-checking</code></dt> 1715 <dt><code>--enable-stage1-checking=<var>list</var></code></dt> 1716 <dd><p>This option affects only bootstrap build. If no <samp>--enable-checking</samp> 1717 option is specified the stage1 compiler is built with ‘<samp>yes</samp>’ checking 1718 enabled, otherwise the stage1 checking flags are the same as specified by 1719 <samp>--enable-checking</samp>. To build the stage1 compiler with 1720 different checking options use <samp>--enable-stage1-checking</samp>. 1721 The list of checking options is the same as for <samp>--enable-checking</samp>. 1722 If your system is too slow or too small to bootstrap a released compiler 1723 with checking for stage1 enabled, you can use ‘<samp>--disable-stage1-checking</samp>’ 1724 to disable checking for the stage1 compiler. 1725 </p> 1726 </dd> 1727 <dt><code>--enable-coverage</code></dt> 1728 <dt><code>--enable-coverage=<var>level</var></code></dt> 1729 <dd><p>With this option, the compiler is built to collect self coverage 1730 information, every time it is run. This is for internal development 1731 purposes, and only works when the compiler is being built with gcc. The 1732 <var>level</var> argument controls whether the compiler is built optimized or 1733 not, values are ‘<samp>opt</samp>’ and ‘<samp>noopt</samp>’. For coverage analysis you 1734 want to disable optimization, for performance analysis you want to 1735 enable optimization. When coverage is enabled, the default level is 1736 without optimization. 1737 </p> 1738 </dd> 1739 <dt><code>--enable-gather-detailed-mem-stats</code></dt> 1740 <dd><p>When this option is specified more detailed information on memory 1741 allocation is gathered. This information is printed when using 1742 <samp>-fmem-report</samp>. 1743 </p> 1744 </dd> 1745 <dt><code>--enable-valgrind-annotations</code></dt> 1746 <dd><p>Mark selected memory related operations in the compiler when run under 1747 valgrind to suppress false positives. 1748 </p> 1749 </dd> 1750 <dt><code>--enable-nls</code></dt> 1751 <dt><code>--disable-nls</code></dt> 1752 <dd><p>The <samp>--enable-nls</samp> option enables Native Language Support (NLS), 1753 which lets GCC output diagnostics in languages other than American 1754 English. Native Language Support is enabled by default if not doing a 1755 canadian cross build. The <samp>--disable-nls</samp> option disables NLS. 1756 </p> 1757 <p>Note that this functionality requires either libintl (provided by GNU 1758 gettext) or C standard library that contains support for gettext (such 1759 as the GNU C Library). 1760 See <a href="#with-included-gettext">–with-included-gettext</a> for more 1761 information on the conditions required to get gettext support. 1762 </p> 1763 </dd> 1764 <dt><code>--with-libintl-prefix=<var>dir</var></code></dt> 1765 <dt><code>--without-libintl-prefix</code></dt> 1766 <dd><p>Searches for libintl in <samp><var>dir</var>/include</samp> and 1767 <samp><var>dir</var>/lib</samp>, or disables manual searching for it, letting the 1768 linker handle it. 1769 </p> 1770 </dd> 1771 <dt><code>--with-libintl-type=<var>type</var></code></dt> 1772 <dd><p>Specifies the type of library to search for when looking for libintl. 1773 <var>type</var> can be one of <code>auto</code>, <code>static</code> or <code>shared</code>. 1774 </p> 1775 <a name="with-included-gettext"></a></dd> 1776 <dt><code>--with-included-gettext</code></dt> 1777 <dd><p>Only available if <samp>gettext</samp> is present in the source tree. 1778 </p> 1779 <p>Forces the gettext tree to be configured to build and use a new static 1780 libintl, overriding the system libintl. Results in GCC being built 1781 against the newly built libintl rather than the system libintl. 1782 </p> 1783 <p>The build system makes a somewhat complicated choice when picking where 1784 to get gettext routines from. The following table is a summary of the 1785 possible options: 1786 </p> 1787 <table> 1788 <thead><tr><th width="12%">GNU gettext present in sources</th><th width="12%">libintl installed on the system</th><th width="12%"><code>gettext</code> present in libc</th><th width="20%"><code>--with-included-gettext</code></th><th width="44%">Effects on localization</th></tr></thead> 1789 <tr><td width="12%">No</td><td width="12%">No</td><td width="12%">No</td><td width="20%">(ignored)</td><td width="44%">No localization</td></tr> 1790 <tr><td width="12%">No</td><td width="12%">No</td><td width="12%">Yes</td><td width="20%">(ignored)</td><td width="44%">Localized, libc gettext</td></tr> 1791 <tr><td width="12%">No</td><td width="12%">Yes</td><td width="12%">No</td><td width="20%">(ignored)</td><td width="44%">Localized, libintl</td></tr> 1792 <tr><td width="12%">No</td><td width="12%">Yes</td><td width="12%">Yes</td><td width="20%">(ignored)</td><td width="44%">Localized, libintl</td></tr> 1793 <tr><td width="12%">Yes</td><td width="12%">No</td><td width="12%">No</td><td width="20%">No</td><td width="44%">Localized, new, static libintl</td></tr> 1794 <tr><td width="12%">Yes</td><td width="12%">No</td><td width="12%">No</td><td width="20%">Yes</td><td width="44%">Localized, new, static libintl</td></tr> 1795 <tr><td width="12%">Yes</td><td width="12%">No</td><td width="12%">Yes</td><td width="20%">No</td><td width="44%">Localized, libc gettext</td></tr> 1796 <tr><td width="12%">Yes</td><td width="12%">No</td><td width="12%">Yes</td><td width="20%">Yes</td><td width="44%">Localized, new, static libintl</td></tr> 1797 <tr><td width="12%">Yes</td><td width="12%">Yes</td><td width="12%">No</td><td width="20%">No</td><td width="44%">Localized, libintl</td></tr> 1798 <tr><td width="12%">Yes</td><td width="12%">Yes</td><td width="12%">No</td><td width="20%">Yes</td><td width="44%">Localized, new, static libintl</td></tr> 1799 <tr><td width="12%">Yes</td><td width="12%">Yes</td><td width="12%">Yes</td><td width="20%">No</td><td width="44%">Localized, libintl</td></tr> 1800 <tr><td width="12%">Yes</td><td width="12%">Yes</td><td width="12%">Yes</td><td width="20%">Yes</td><td width="44%">Localized, new, static libintl</td></tr> 1801 </table> 1802 1803 </dd> 1804 <dt><code>--with-catgets</code></dt> 1805 <dd><p>If NLS is enabled, and if the host lacks <code>gettext</code> but has the 1806 inferior <code>catgets</code> interface, the GCC build procedure normally 1807 ignores <code>catgets</code> and instead uses GCC’s copy of the GNU 1808 <code>gettext</code> library. The <samp>--with-catgets</samp> option causes the 1809 build procedure to use the host’s <code>catgets</code> in this situation. 1810 </p> 1811 </dd> 1812 <dt><code>--with-libiconv-prefix=<var>dir</var></code></dt> 1813 <dd><p>Search for libiconv header files in <samp><var>dir</var>/include</samp> and 1814 libiconv library files in <samp><var>dir</var>/lib</samp>. 1815 </p> 1816 </dd> 1817 <dt><code>--enable-obsolete</code></dt> 1818 <dd><p>Enable configuration for an obsoleted system. If you attempt to 1819 configure GCC for a system (build, host, or target) which has been 1820 obsoleted, and you do not specify this flag, configure will halt with an 1821 error message. 1822 </p> 1823 <p>All support for systems which have been obsoleted in one release of GCC 1824 is removed entirely in the next major release, unless someone steps 1825 forward to maintain the port. 1826 </p> 1827 </dd> 1828 <dt><code>--enable-decimal-float</code></dt> 1829 <dt><code>--enable-decimal-float=yes</code></dt> 1830 <dt><code>--enable-decimal-float=no</code></dt> 1831 <dt><code>--enable-decimal-float=bid</code></dt> 1832 <dt><code>--enable-decimal-float=dpd</code></dt> 1833 <dt><code>--disable-decimal-float</code></dt> 1834 <dd><p>Enable (or disable) support for the C decimal floating point extension 1835 that is in the IEEE 754-2008 standard. This is enabled by default 1836 only on AArch64, PowerPC, i386, and x86_64 GNU/Linux systems. Other 1837 systems may also support it, but require the user to specifically 1838 enable it. You can optionally control which decimal floating point 1839 format is used (either ‘<samp>bid</samp>’ or ‘<samp>dpd</samp>’). The ‘<samp>bid</samp>’ 1840 (binary integer decimal) format is default on AArch64, i386 and x86_64 1841 systems, and the ‘<samp>dpd</samp>’ (densely packed decimal) format is default 1842 on PowerPC systems. 1843 </p> 1844 </dd> 1845 <dt><code>--enable-fixed-point</code></dt> 1846 <dt><code>--disable-fixed-point</code></dt> 1847 <dd><p>Enable (or disable) support for C fixed-point arithmetic. 1848 This option is enabled by default for some targets (such as MIPS) which 1849 have hardware-support for fixed-point operations. On other targets, you 1850 may enable this option manually. 1851 </p> 1852 </dd> 1853 <dt><code>--with-long-double-128</code></dt> 1854 <dd><p>Specify if <code>long double</code> type should be 128-bit by default on selected 1855 GNU/Linux architectures. If using <code>--without-long-double-128</code>, 1856 <code>long double</code> will be by default 64-bit, the same as <code>double</code> type. 1857 When neither of these configure options are used, the default will be 1858 128-bit <code>long double</code> when built against GNU C Library 2.4 and later, 1859 64-bit <code>long double</code> otherwise. 1860 </p> 1861 </dd> 1862 <dt><code>--with-long-double-format=ibm</code></dt> 1863 <dt><code>--with-long-double-format=ieee</code></dt> 1864 <dd><p>Specify whether <code>long double</code> uses the IBM extended double format 1865 or the IEEE 128-bit floating point format on PowerPC Linux systems. 1866 This configuration switch will only work on little endian PowerPC 1867 Linux systems and on big endian 64-bit systems where the default cpu 1868 is at least power7 (i.e. <samp>--with-cpu=power7</samp>, 1869 <samp>--with-cpu=power8</samp>, or <samp>--with-cpu=power9</samp> is used). 1870 </p> 1871 <p>If you use the <samp>--with-long-double-64</samp> configuration option, 1872 the <samp>--with-long-double-format=ibm</samp> and 1873 <samp>--with-long-double-format=ieee</samp> options are ignored. 1874 </p> 1875 <p>The default <code>long double</code> format is to use IBM extended double. 1876 Until all of the libraries are converted to use IEEE 128-bit floating 1877 point, it is not recommended to use 1878 <samp>--with-long-double-format=ieee</samp>. 1879 </p> 1880 </dd> 1881 <dt><code>--enable-fdpic</code></dt> 1882 <dd><p>On SH Linux systems, generate ELF FDPIC code. 1883 </p> 1884 </dd> 1885 <dt><code>--with-gmp=<var>pathname</var></code></dt> 1886 <dt><code>--with-gmp-include=<var>pathname</var></code></dt> 1887 <dt><code>--with-gmp-lib=<var>pathname</var></code></dt> 1888 <dt><code>--with-mpfr=<var>pathname</var></code></dt> 1889 <dt><code>--with-mpfr-include=<var>pathname</var></code></dt> 1890 <dt><code>--with-mpfr-lib=<var>pathname</var></code></dt> 1891 <dt><code>--with-mpc=<var>pathname</var></code></dt> 1892 <dt><code>--with-mpc-include=<var>pathname</var></code></dt> 1893 <dt><code>--with-mpc-lib=<var>pathname</var></code></dt> 1894 <dd><p>If you want to build GCC but do not have the GMP library, the MPFR 1895 library and/or the MPC library installed in a standard location and 1896 do not have their sources present in the GCC source tree then you 1897 can explicitly specify the directory where they are installed 1898 (‘<samp>--with-gmp=<var>gmpinstalldir</var></samp>’, 1899 ‘<samp>--with-mpfr=<var>mpfrinstalldir</var></samp>’, 1900 ‘<samp>--with-mpc=<var>mpcinstalldir</var></samp>’). The 1901 <samp>--with-gmp=<var>gmpinstalldir</var></samp> option is shorthand for 1902 <samp>--with-gmp-lib=<var>gmpinstalldir</var>/lib</samp> and 1903 <samp>--with-gmp-include=<var>gmpinstalldir</var>/include</samp>. Likewise the 1904 <samp>--with-mpfr=<var>mpfrinstalldir</var></samp> option is shorthand for 1905 <samp>--with-mpfr-lib=<var>mpfrinstalldir</var>/lib</samp> and 1906 <samp>--with-mpfr-include=<var>mpfrinstalldir</var>/include</samp>, also the 1907 <samp>--with-mpc=<var>mpcinstalldir</var></samp> option is shorthand for 1908 <samp>--with-mpc-lib=<var>mpcinstalldir</var>/lib</samp> and 1909 <samp>--with-mpc-include=<var>mpcinstalldir</var>/include</samp>. If these 1910 shorthand assumptions are not correct, you can use the explicit 1911 include and lib options directly. You might also need to ensure the 1912 shared libraries can be found by the dynamic linker when building and 1913 using GCC, for example by setting the runtime shared library path 1914 variable (<code>LD_LIBRARY_PATH</code> on GNU/Linux and Solaris systems). 1915 </p> 1916 <p>These flags are applicable to the host platform only. When building 1917 a cross compiler, they will not be used to configure target libraries. 1918 </p> 1919 </dd> 1920 <dt><code>--with-isl=<var>pathname</var></code></dt> 1921 <dt><code>--with-isl-include=<var>pathname</var></code></dt> 1922 <dt><code>--with-isl-lib=<var>pathname</var></code></dt> 1923 <dd><p>If you do not have the isl library installed in a standard location and you 1924 want to build GCC, you can explicitly specify the directory where it is 1925 installed (‘<samp>--with-isl=<var>islinstalldir</var></samp>’). The 1926 <samp>--with-isl=<var>islinstalldir</var></samp> option is shorthand for 1927 <samp>--with-isl-lib=<var>islinstalldir</var>/lib</samp> and 1928 <samp>--with-isl-include=<var>islinstalldir</var>/include</samp>. If this 1929 shorthand assumption is not correct, you can use the explicit 1930 include and lib options directly. 1931 </p> 1932 <p>These flags are applicable to the host platform only. When building 1933 a cross compiler, they will not be used to configure target libraries. 1934 </p> 1935 </dd> 1936 <dt><code>--with-stage1-ldflags=<var>flags</var></code></dt> 1937 <dd><p>This option may be used to set linker flags to be used when linking 1938 stage 1 of GCC. These are also used when linking GCC if configured with 1939 <samp>--disable-bootstrap</samp>. If <samp>--with-stage1-libs</samp> is not set to a 1940 value, then the default is ‘<samp>-static-libstdc++ -static-libgcc</samp>’, if 1941 supported. 1942 </p> 1943 </dd> 1944 <dt><code>--with-stage1-libs=<var>libs</var></code></dt> 1945 <dd><p>This option may be used to set libraries to be used when linking stage 1 1946 of GCC. These are also used when linking GCC if configured with 1947 <samp>--disable-bootstrap</samp>. 1948 </p> 1949 </dd> 1950 <dt><code>--with-boot-ldflags=<var>flags</var></code></dt> 1951 <dd><p>This option may be used to set linker flags to be used when linking 1952 stage 2 and later when bootstrapping GCC. If –with-boot-libs 1953 is not is set to a value, then the default is 1954 ‘<samp>-static-libstdc++ -static-libgcc</samp>’. 1955 </p> 1956 </dd> 1957 <dt><code>--with-boot-libs=<var>libs</var></code></dt> 1958 <dd><p>This option may be used to set libraries to be used when linking stage 2 1959 and later when bootstrapping GCC. 1960 </p> 1961 </dd> 1962 <dt><code>--with-debug-prefix-map=<var>map</var></code></dt> 1963 <dd><p>Convert source directory names using <samp>-fdebug-prefix-map</samp> when 1964 building runtime libraries. ‘<samp><var>map</var></samp>’ is a space-separated 1965 list of maps of the form ‘<samp><var>old</var>=<var>new</var></samp>’. 1966 </p> 1967 </dd> 1968 <dt><code>--enable-linker-build-id</code></dt> 1969 <dd><p>Tells GCC to pass <samp>--build-id</samp> option to the linker for all final 1970 links (links performed without the <samp>-r</samp> or <samp>--relocatable</samp> 1971 option), if the linker supports it. If you specify 1972 <samp>--enable-linker-build-id</samp>, but your linker does not 1973 support <samp>--build-id</samp> option, a warning is issued and the 1974 <samp>--enable-linker-build-id</samp> option is ignored. The default is off. 1975 </p> 1976 </dd> 1977 <dt><code>--with-linker-hash-style=<var>choice</var></code></dt> 1978 <dd><p>Tells GCC to pass <samp>--hash-style=<var>choice</var></samp> option to the 1979 linker for all final links. <var>choice</var> can be one of 1980 ‘<samp>sysv</samp>’, ‘<samp>gnu</samp>’, and ‘<samp>both</samp>’ where ‘<samp>sysv</samp>’ is the default. 1981 </p> 1982 </dd> 1983 <dt><code>--enable-gnu-unique-object</code></dt> 1984 <dt><code>--disable-gnu-unique-object</code></dt> 1985 <dd><p>Tells GCC to use the gnu_unique_object relocation for C++ template 1986 static data members and inline function local statics. Enabled by 1987 default for a toolchain with an assembler that accepts it and 1988 GLIBC 2.11 or above, otherwise disabled. 1989 </p> 1990 </dd> 1991 <dt><code>--with-diagnostics-color=<var>choice</var></code></dt> 1992 <dd><p>Tells GCC to use <var>choice</var> as the default for <samp>-fdiagnostics-color=</samp> 1993 option (if not used explicitly on the command line). <var>choice</var> 1994 can be one of ‘<samp>never</samp>’, ‘<samp>auto</samp>’, ‘<samp>always</samp>’, and ‘<samp>auto-if-env</samp>’ 1995 where ‘<samp>auto</samp>’ is the default. ‘<samp>auto-if-env</samp>’ makes 1996 <samp>-fdiagnostics-color=auto</samp> the default if <code>GCC_COLORS</code> 1997 is present and non-empty in the environment of the compiler, and 1998 <samp>-fdiagnostics-color=never</samp> otherwise. 1999 </p> 2000 </dd> 2001 <dt><code>--with-diagnostics-urls=<var>choice</var></code></dt> 2002 <dd><p>Tells GCC to use <var>choice</var> as the default for <samp>-fdiagnostics-urls=</samp> 2003 option (if not used explicitly on the command line). <var>choice</var> 2004 can be one of ‘<samp>never</samp>’, ‘<samp>auto</samp>’, ‘<samp>always</samp>’, and ‘<samp>auto-if-env</samp>’ 2005 where ‘<samp>auto</samp>’ is the default. ‘<samp>auto-if-env</samp>’ makes 2006 <samp>-fdiagnostics-urls=auto</samp> the default if <code>GCC_URLS</code> 2007 or <code>TERM_URLS</code> is present and non-empty in the environment of the 2008 compiler, and <samp>-fdiagnostics-urls=never</samp> otherwise. 2009 </p> 2010 </dd> 2011 <dt><code>--enable-lto</code></dt> 2012 <dt><code>--disable-lto</code></dt> 2013 <dd><p>Enable support for link-time optimization (LTO). This is enabled by 2014 default, and may be disabled using <samp>--disable-lto</samp>. 2015 </p> 2016 </dd> 2017 <dt><code>--enable-linker-plugin-configure-flags=FLAGS</code></dt> 2018 <dt><code>--enable-linker-plugin-flags=FLAGS</code></dt> 2019 <dd><p>By default, linker plugins (such as the LTO plugin) are built for the 2020 host system architecture. For the case that the linker has a 2021 different (but run-time compatible) architecture, these flags can be 2022 specified to build plugins that are compatible to the linker. For 2023 example, if you are building GCC for a 64-bit x86_64 2024 (‘<samp>x86_64-pc-linux-gnu</samp>’) host system, but have a 32-bit x86 2025 GNU/Linux (‘<samp>i686-pc-linux-gnu</samp>’) linker executable (which is 2026 executable on the former system), you can configure GCC as follows for 2027 getting compatible linker plugins: 2028 </p> 2029 <div class="smallexample"> 2030 <pre class="smallexample">% <var>srcdir</var>/configure \ 2031 --host=x86_64-pc-linux-gnu \ 2032 --enable-linker-plugin-configure-flags=--host=i686-pc-linux-gnu \ 2033 --enable-linker-plugin-flags='CC=gcc\ -m32\ -Wl,-rpath,[...]/i686-pc-linux-gnu/lib' 2034 </pre></div> 2035 2036 </dd> 2037 <dt><code>--with-plugin-ld=<var>pathname</var></code></dt> 2038 <dd><p>Enable an alternate linker to be used at link-time optimization (LTO) 2039 link time when <samp>-fuse-linker-plugin</samp> is enabled. 2040 This linker should have plugin support such as gold starting with 2041 version 2.20 or GNU ld starting with version 2.21. 2042 See <samp>-fuse-linker-plugin</samp> for details. 2043 </p> 2044 </dd> 2045 <dt><code>--enable-canonical-system-headers</code></dt> 2046 <dt><code>--disable-canonical-system-headers</code></dt> 2047 <dd><p>Enable system header path canonicalization for <samp>libcpp</samp>. This can 2048 produce shorter header file paths in diagnostics and dependency output 2049 files, but these changed header paths may conflict with some compilation 2050 environments. Enabled by default, and may be disabled using 2051 <samp>--disable-canonical-system-headers</samp>. 2052 </p> 2053 </dd> 2054 <dt><code>--with-glibc-version=<var>major</var>.<var>minor</var></code></dt> 2055 <dd><p>Tell GCC that when the GNU C Library (glibc) is used on the target it 2056 will be version <var>major</var>.<var>minor</var> or later. Normally this can 2057 be detected from the C library’s header files, but this option may be 2058 needed when bootstrapping a cross toolchain without the header files 2059 available for building the initial bootstrap compiler. 2060 </p> 2061 <p>If GCC is configured with some multilibs that use glibc and some that 2062 do not, this option applies only to the multilibs that use glibc. 2063 However, such configurations may not work well as not all the relevant 2064 configuration in GCC is on a per-multilib basis. 2065 </p> 2066 </dd> 2067 <dt><code>--enable-as-accelerator-for=<var>target</var></code></dt> 2068 <dd><p>Build as offload target compiler. Specify offload host triple by <var>target</var>. 2069 </p> 2070 </dd> 2071 <dt><code>--enable-offload-targets=<var>target1</var>[=<var>path1</var>],…,<var>targetN</var>[=<var>pathN</var>]</code></dt> 2072 <dd><p>Enable offloading to targets <var>target1</var>, …, <var>targetN</var>. 2073 Offload compilers are expected to be already installed. Default search 2074 path for them is <samp><var>exec-prefix</var></samp>, but it can be changed by 2075 specifying paths <var>path1</var>, …, <var>pathN</var>. 2076 </p> 2077 <div class="smallexample"> 2078 <pre class="smallexample">% <var>srcdir</var>/configure \ 2079 --enable-offload-targets=amdgcn-amdhsa,nvptx-none 2080 </pre></div> 2081 2082 </dd> 2083 <dt><code>--enable-offload-defaulted</code></dt> 2084 <dd> 2085 <p>Tell GCC that configured but not installed offload compilers and libgomp 2086 plugins are silently ignored. Useful for distribution compilers where 2087 those are in separate optional packages and where the presence or absence 2088 of those optional packages should determine the actual supported offloading 2089 target set rather than the GCC configure-time selection. 2090 </p> 2091 </dd> 2092 <dt><code>--enable-cet</code></dt> 2093 <dt><code>--disable-cet</code></dt> 2094 <dd><p>Enable building target run-time libraries with control-flow 2095 instrumentation, see <samp>-fcf-protection</samp> option. When 2096 <code>--enable-cet</code> is specified target libraries are configured 2097 to add <samp>-fcf-protection</samp> and, if needed, other target 2098 specific options to a set of building options. 2099 </p> 2100 <p><code>--enable-cet=auto</code> is default. CET is enabled on Linux/x86 if 2101 target binutils supports <code>Intel CET</code> instructions and disabled 2102 otherwise. In this case, the target libraries are configured to get 2103 additional <samp>-fcf-protection</samp> option. 2104 </p> 2105 </dd> 2106 <dt><code>--with-riscv-attribute=‘<samp>yes</samp>’, ‘<samp>no</samp>’ or ‘<samp>default</samp>’</code></dt> 2107 <dd><p>Generate RISC-V attribute by default, in order to record extra build 2108 information in object. 2109 </p> 2110 <p>The option is disabled by default. It is enabled on RISC-V/ELF (bare-metal) 2111 target if target binutils supported. 2112 </p> 2113 </dd> 2114 <dt><code>--enable-s390-excess-float-precision</code></dt> 2115 <dt><code>--disable-s390-excess-float-precision</code></dt> 2116 <dd><p>On s390(x) targets, enable treatment of float expressions with double precision 2117 when in standards-compliant mode (e.g., when <code>--std=c99</code> or 2118 <code>-fexcess-precision=standard</code> are given). 2119 </p> 2120 <p>For a native build and cross compiles that have target headers, the option’s 2121 default is derived from glibc’s behavior. When glibc clamps float_t to double, 2122 GCC follows and enables the option. For other cross compiles, the default is 2123 disabled. 2124 </p> 2125 </dd> 2126 <dt><code>--with-zstd=<var>pathname</var></code></dt> 2127 <dt><code>--with-zstd-include=<var>pathname</var></code></dt> 2128 <dt><code>--with-zstd-lib=<var>pathname</var></code></dt> 2129 <dd><p>If you do not have the <code>zstd</code> library installed in a standard 2130 location and you want to build GCC, you can explicitly specify the 2131 directory where it is installed (‘<samp>--with-zstd=<var>zstdinstalldir</var></samp>’). 2132 The <samp>--with-zstd=<var>zstdinstalldir</var></samp> option is shorthand for 2133 <samp>--with-zstd-lib=<var>zstdinstalldir</var>/lib</samp> and 2134 <samp>--with-zstd-include=<var>zstdinstalldir</var>/include</samp>. If this 2135 shorthand assumption is not correct, you can use the explicit 2136 include and lib options directly. 2137 </p> 2138 <p>These flags are applicable to the host platform only. When building 2139 a cross compiler, they will not be used to configure target libraries. 2140 </p></dd> 2141 </dl> 2142 2143 <a name="Cross-Compiler-Specific-Options"></a> 2144 <h4 class="subheading">Cross-Compiler-Specific Options</h4> 2145 <p>The following options only apply to building cross compilers. 2146 </p> 2147 <dl compact="compact"> 2148 <dt><code>--with-toolexeclibdir=<var>dir</var></code></dt> 2149 <dd><p>Specify the installation directory for libraries built with a cross compiler. 2150 The default is <samp>${gcc_tooldir}/lib</samp>. 2151 </p> 2152 </dd> 2153 <dt><code>--with-sysroot</code></dt> 2154 <dt><code>--with-sysroot=<var>dir</var></code></dt> 2155 <dd><p>Tells GCC to consider <var>dir</var> as the root of a tree that contains 2156 (a subset of) the root filesystem of the target operating system. 2157 Target system headers, libraries and run-time object files will be 2158 searched for in there. More specifically, this acts as if 2159 <samp>--sysroot=<var>dir</var></samp> was added to the default options of the built 2160 compiler. The specified directory is not copied into the 2161 install tree, unlike the options <samp>--with-headers</samp> and 2162 <samp>--with-libs</samp> that this option obsoletes. The default value, 2163 in case <samp>--with-sysroot</samp> is not given an argument, is 2164 <samp>${gcc_tooldir}/sys-root</samp>. If the specified directory is a 2165 subdirectory of <samp>${exec_prefix}</samp>, then it will be found relative to 2166 the GCC binaries if the installation tree is moved. 2167 </p> 2168 <p>This option affects the system root for the compiler used to build 2169 target libraries (which runs on the build system) and the compiler newly 2170 installed with <code>make install</code>; it does not affect the compiler which is 2171 used to build GCC itself. 2172 </p> 2173 <p>If you specify the <samp>--with-native-system-header-dir=<var>dirname</var></samp> 2174 option then the compiler will search that directory within <var>dirname</var> for 2175 native system headers rather than the default <samp>/usr/include</samp>. 2176 </p> 2177 </dd> 2178 <dt><code>--with-build-sysroot</code></dt> 2179 <dt><code>--with-build-sysroot=<var>dir</var></code></dt> 2180 <dd><p>Tells GCC to consider <var>dir</var> as the system root (see 2181 <samp>--with-sysroot</samp>) while building target libraries, instead of 2182 the directory specified with <samp>--with-sysroot</samp>. This option is 2183 only useful when you are already using <samp>--with-sysroot</samp>. You 2184 can use <samp>--with-build-sysroot</samp> when you are configuring with 2185 <samp>--prefix</samp> set to a directory that is different from the one in 2186 which you are installing GCC and your target libraries. 2187 </p> 2188 <p>This option affects the system root for the compiler used to build 2189 target libraries (which runs on the build system); it does not affect 2190 the compiler which is used to build GCC itself. 2191 </p> 2192 <p>If you specify the <samp>--with-native-system-header-dir=<var>dirname</var></samp> 2193 option then the compiler will search that directory within <var>dirname</var> for 2194 native system headers rather than the default <samp>/usr/include</samp>. 2195 </p> 2196 </dd> 2197 <dt><code>--with-headers</code></dt> 2198 <dt><code>--with-headers=<var>dir</var></code></dt> 2199 <dd><p>Deprecated in favor of <samp>--with-sysroot</samp>. 2200 Specifies that target headers are available when building a cross compiler. 2201 The <var>dir</var> argument specifies a directory which has the target include 2202 files. These include files will be copied into the <samp>gcc</samp> install 2203 directory. <em>This option with the <var>dir</var> argument is required</em> when 2204 building a cross compiler, if <samp><var>prefix</var>/<var>target</var>/sys-include</samp> 2205 doesn’t pre-exist. If <samp><var>prefix</var>/<var>target</var>/sys-include</samp> does 2206 pre-exist, the <var>dir</var> argument may be omitted. <code>fixincludes</code> 2207 will be run on these files to make them compatible with GCC. 2208 </p> 2209 </dd> 2210 <dt><code>--without-headers</code></dt> 2211 <dd><p>Tells GCC not use any target headers from a libc when building a cross 2212 compiler. When crossing to GNU/Linux, you need the headers so GCC 2213 can build the exception handling for libgcc. 2214 </p> 2215 </dd> 2216 <dt><code>--with-libs</code></dt> 2217 <dt><code>--with-libs="<var>dir1</var> <var>dir2</var> … <var>dirN</var>"</code></dt> 2218 <dd><p>Deprecated in favor of <samp>--with-sysroot</samp>. 2219 Specifies a list of directories which contain the target runtime 2220 libraries. These libraries will be copied into the <samp>gcc</samp> install 2221 directory. If the directory list is omitted, this option has no 2222 effect. 2223 </p> 2224 </dd> 2225 <dt><code>--with-newlib</code></dt> 2226 <dd><p>Specifies that ‘<samp>newlib</samp>’ is 2227 being used as the target C library. This causes <code>__eprintf</code> to be 2228 omitted from <samp>libgcc.a</samp> on the assumption that it will be provided by 2229 ‘<samp>newlib</samp>’. 2230 </p> 2231 <a name="avr"></a> 2232 </dd> 2233 <dt><code>--with-avrlibc</code></dt> 2234 <dd><p>Only supported for the AVR target. Specifies that ‘<samp>AVR-Libc</samp>’ is 2235 being used as the target C library. This causes float support 2236 functions like <code>__addsf3</code> to be omitted from <samp>libgcc.a</samp> on 2237 the assumption that it will be provided by <samp>libm.a</samp>. For more 2238 technical details, cf. <a href="https://gcc.gnu.org/PR54461">PR54461</a>. 2239 It is not supported for 2240 RTEMS configurations, which currently use newlib. The option is 2241 supported since version 4.7.2 and is the default in 4.8.0 and newer. 2242 </p> 2243 </dd> 2244 <dt><code>--with-double={32|64|32,64|64,32}</code></dt> 2245 <dt><code>--with-long-double={32|64|32,64|64,32|double}</code></dt> 2246 <dd><p>Only supported for the AVR target since version 10. 2247 Specify the default layout available for the C/C++ ‘<samp>double</samp>’ 2248 and ‘<samp>long double</samp>’ type, respectively. The following rules apply: 2249 </p><ul> 2250 <li> The first value after the ‘<samp>=</samp>’ specifies the default layout (in bits) 2251 of the type and also the default for the <samp>-mdouble=</samp> resp. 2252 <samp>-mlong-double=</samp> compiler option. 2253 </li><li> If more than one value is specified, respective multilib variants are 2254 available, and <samp>-mdouble=</samp> resp. <samp>-mlong-double=</samp> acts 2255 as a multilib option. 2256 </li><li> If <samp>--with-long-double=double</samp> is specified, ‘<samp>double</samp>’ and 2257 ‘<samp>long double</samp>’ will have the same layout. 2258 </li><li> The defaults are <samp>--with-long-double=64,32</samp> and 2259 <samp>--with-double=32,64</samp>. The default ‘<samp>double</samp>’ layout imposed by 2260 the latter is compatible with older versions of the compiler that implement 2261 ‘<samp>double</samp>’ as a 32-bit type, which does not comply to the language standard. 2262 </li></ul> 2263 <p>Not all combinations of <samp>--with-double=</samp> and 2264 <samp>--with-long-double=</samp> are valid. For example, the combination 2265 <samp>--with-double=32,64</samp> <samp>--with-long-double=32</samp> will be 2266 rejected because the first option specifies the availability of 2267 multilibs for ‘<samp>double</samp>’, whereas the second option implies 2268 that ‘<samp>long double</samp>’ — and hence also ‘<samp>double</samp>’ — is always 2269 32 bits wide. 2270 </p> 2271 </dd> 2272 <dt><code>--with-double-comparison={tristate|bool|libf7}</code></dt> 2273 <dd><p>Only supported for the AVR target since version 10. 2274 Specify what result format is returned by library functions that 2275 compare 64-bit floating point values (<code>DFmode</code>). 2276 The GCC default is ‘<samp>tristate</samp>’. If the floating point 2277 implementation returns a boolean instead, set it to ‘<samp>bool</samp>’. 2278 </p> 2279 </dd> 2280 <dt><code>--with-libf7={libgcc|math|math-symbols|no}</code></dt> 2281 <dd><p>Only supported for the AVR target since version 10. 2282 Specify to which degree code from LibF7 is included in libgcc. 2283 LibF7 is an ad-hoc, AVR-specific, 64-bit floating point emulation 2284 written in C and (inline) assembly. ‘<samp>libgcc</samp>’ adds support 2285 for functions that one would usually expect in libgcc like double addition, 2286 double comparisons and double conversions. ‘<samp>math</samp>’ also adds routines 2287 that one would expect in <samp>libm.a</samp>, but with <code>__</code> (two underscores) 2288 prepended to the symbol names as specified by <samp>math.h</samp>. 2289 ‘<samp>math-symbols</samp>’ also defines weak aliases for the functions 2290 declared in <samp>math.h</samp>. However, <code>--with-libf7</code> won’t 2291 install no <samp>math.h</samp> header file whatsoever, this file must come 2292 from elsewhere. This option sets <samp>--with-double-comparison</samp> 2293 to ‘<samp>bool</samp>’. 2294 </p> 2295 </dd> 2296 <dt><code>--with-nds32-lib=<var>library</var></code></dt> 2297 <dd><p>Specifies that <var>library</var> setting is used for building <samp>libgcc.a</samp>. 2298 Currently, the valid <var>library</var> is ‘<samp>newlib</samp>’ or ‘<samp>mculib</samp>’. 2299 This option is only supported for the NDS32 target. 2300 </p> 2301 </dd> 2302 <dt><code>--with-build-time-tools=<var>dir</var></code></dt> 2303 <dd><p>Specifies where to find the set of target tools (assembler, linker, etc.) 2304 that will be used while building GCC itself. This option can be useful 2305 if the directory layouts are different between the system you are building 2306 GCC on, and the system where you will deploy it. 2307 </p> 2308 <p>For example, on an ‘<samp>ia64-hp-hpux</samp>’ system, you may have the GNU 2309 assembler and linker in <samp>/usr/bin</samp>, and the native tools in a 2310 different path, and build a toolchain that expects to find the 2311 native tools in <samp>/usr/bin</samp>. 2312 </p> 2313 <p>When you use this option, you should ensure that <var>dir</var> includes 2314 <code>ar</code>, <code>as</code>, <code>ld</code>, <code>nm</code>, 2315 <code>ranlib</code> and <code>strip</code> if necessary, and possibly 2316 <code>objdump</code>. Otherwise, GCC may use an inconsistent set of 2317 tools. 2318 </p></dd> 2319 </dl> 2320 2321 <a name="Overriding-configure-test-results"></a> 2322 <h4 class="subsubheading">Overriding <code>configure</code> test results</h4> 2323 2324 <p>Sometimes, it might be necessary to override the result of some 2325 <code>configure</code> test, for example in order to ease porting to a new 2326 system or work around a bug in a test. The toplevel <code>configure</code> 2327 script provides three variables for this: 2328 </p> 2329 <dl compact="compact"> 2330 <dd> 2331 <a name="index-build_005fconfigargs"></a> 2332 </dd> 2333 <dt><code>build_configargs</code></dt> 2334 <dd><p>The contents of this variable is passed to all build <code>configure</code> 2335 scripts. 2336 </p> 2337 <a name="index-host_005fconfigargs"></a> 2338 </dd> 2339 <dt><code>host_configargs</code></dt> 2340 <dd><p>The contents of this variable is passed to all host <code>configure</code> 2341 scripts. 2342 </p> 2343 <a name="index-target_005fconfigargs"></a> 2344 </dd> 2345 <dt><code>target_configargs</code></dt> 2346 <dd><p>The contents of this variable is passed to all target <code>configure</code> 2347 scripts. 2348 </p> 2349 </dd> 2350 </dl> 2351 2352 <p>In order to avoid shell and <code>make</code> quoting issues for complex 2353 overrides, you can pass a setting for <code>CONFIG_SITE</code> and set 2354 variables in the site file. 2355 </p> 2356 <a name="Objective-C-Specific-Options"></a> 2357 <h4 class="subheading">Objective-C-Specific Options</h4> 2358 2359 <p>The following options apply to the build of the Objective-C runtime library. 2360 </p> 2361 <dl compact="compact"> 2362 <dt><code>--enable-objc-gc</code></dt> 2363 <dd><p>Specify that an additional variant of the GNU Objective-C runtime library 2364 is built, using an external build of the Boehm-Demers-Weiser garbage 2365 collector (<a href="https://www.hboehm.info/gc/">https://www.hboehm.info/gc/</a>). This library needs to be 2366 available for each multilib variant, unless configured with 2367 <samp>--enable-objc-gc=‘<samp>auto</samp>’</samp> in which case the build of the 2368 additional runtime library is skipped when not available and the build 2369 continues. 2370 </p> 2371 </dd> 2372 <dt><code>--with-target-bdw-gc=<var>list</var></code></dt> 2373 <dt><code>--with-target-bdw-gc-include=<var>list</var></code></dt> 2374 <dt><code>--with-target-bdw-gc-lib=<var>list</var></code></dt> 2375 <dd><p>Specify search directories for the garbage collector header files and 2376 libraries. <var>list</var> is a comma separated list of key value pairs of the 2377 form ‘<samp><var>multilibdir</var>=<var>path</var></samp>’, where the default multilib key 2378 is named as ‘<samp>.</samp>’ (dot), or is omitted (e.g. 2379 ‘<samp>--with-target-bdw-gc=/opt/bdw-gc,32=/opt-bdw-gc32</samp>’). 2380 </p> 2381 <p>The options <samp>--with-target-bdw-gc-include</samp> and 2382 <samp>--with-target-bdw-gc-lib</samp> must always be specified together 2383 for each multilib variant and they take precedence over 2384 <samp>--with-target-bdw-gc</samp>. If <samp>--with-target-bdw-gc-include</samp> 2385 is missing values for a multilib, then the value for the default 2386 multilib is used (e.g. ‘<samp>--with-target-bdw-gc-include=/opt/bdw-gc/include</samp>’ 2387 ‘<samp>--with-target-bdw-gc-lib=/opt/bdw-gc/lib64,32=/opt-bdw-gc/lib32</samp>’). 2388 If none of these options are specified, the library is assumed in 2389 default locations. 2390 </p></dd> 2391 </dl> 2392 2393 <a name="D-Specific-Options"></a> 2394 <h4 class="subheading">D-Specific Options</h4> 2395 2396 <p>The following options apply to the build of the D runtime library. 2397 </p> 2398 <dl compact="compact"> 2399 <dt><code>--enable-libphobos-checking</code></dt> 2400 <dt><code>--disable-libphobos-checking</code></dt> 2401 <dt><code>--enable-libphobos-checking=<var>list</var></code></dt> 2402 <dd><p>This option controls whether run-time checks and contracts are compiled into 2403 the D runtime library. When the option is not specified, the library is built 2404 with ‘<samp>release</samp>’ checking. When the option is specified without a 2405 <var>list</var>, the result is the same as ‘<samp>--enable-libphobos-checking=yes</samp>’. 2406 Likewise, ‘<samp>--disable-libphobos-checking</samp>’ is equivalent to 2407 ‘<samp>--enable-libphobos-checking=no</samp>’. 2408 </p> 2409 <p>The categories of checks available in <var>list</var> are ‘<samp>yes</samp>’ (compiles 2410 libphobos with <samp>-fno-release</samp>), ‘<samp>no</samp>’ (compiles libphobos with 2411 <samp>-frelease</samp>), ‘<samp>all</samp>’ (same as ‘<samp>yes</samp>’), ‘<samp>none</samp>’ or 2412 ‘<samp>release</samp>’ (same as ‘<samp>no</samp>’). 2413 </p> 2414 <p>Individual checks available in <var>list</var> are ‘<samp>assert</samp>’ (compiles libphobos 2415 with an extra option <samp>-fassert</samp>). 2416 </p> 2417 </dd> 2418 <dt><code>--with-libphobos-druntime-only</code></dt> 2419 <dt><code>--with-libphobos-druntime-only=<var>choice</var></code></dt> 2420 <dd><p>Specify whether to build only the core D runtime library (druntime), or both 2421 the core and standard library (phobos) into libphobos. This is useful for 2422 targets that have full support in druntime, but no or incomplete support 2423 in phobos. <var>choice</var> can be one of ‘<samp>auto</samp>’, ‘<samp>yes</samp>’, and ‘<samp>no</samp>’ 2424 where ‘<samp>auto</samp>’ is the default. 2425 </p> 2426 <p>When the option is not specified, the default choice ‘<samp>auto</samp>’ means that it 2427 is inferred whether the target has support for the phobos standard library. 2428 When the option is specified without a <var>choice</var>, the result is the same as 2429 ‘<samp>--with-libphobos-druntime-only=yes</samp>’. 2430 </p> 2431 </dd> 2432 <dt><code>--with-target-system-zlib</code></dt> 2433 <dd><p>Use installed ‘<samp>zlib</samp>’ rather than that included with GCC. This needs 2434 to be available for each multilib variant, unless configured with 2435 <samp>--with-target-system-zlib=‘<samp>auto</samp>’</samp> in which case the GCC included 2436 ‘<samp>zlib</samp>’ is only used when the system installed library is not available. 2437 </p></dd> 2438 </dl> 2439 2440 <hr /> 2441 <p> 2442 <p><a href="./index.html">Return to the GCC Installation page</a> 2443 </p> 2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 </body> 2455 </html> 2456
Indexes created Wed Jul 15 00:26:21 UTC 2026