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| author | alk3pInjection <webmaster@raspii.tech> | 2024-02-04 16:16:35 +0800 |
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| committer | alk3pInjection <webmaster@raspii.tech> | 2024-02-04 16:16:35 +0800 |
| commit | abdaadbcae30fe0c9a66c7516798279fdfd97750 (patch) | |
| tree | 00a54a6e25601e43876d03c1a4a12a749d4a914c /share/doc/gccinstall/configure.html | |
https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads
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diff --git a/share/doc/gccinstall/configure.html b/share/doc/gccinstall/configure.html new file mode 100644 index 0000000..c31ced3 --- /dev/null +++ b/share/doc/gccinstall/configure.html @@ -0,0 +1,2330 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> +<html> +<!-- Copyright (C) 1988-2023 Free Software Foundation, Inc. + +Permission is granted to copy, distribute and/or modify this document +under the terms of the GNU Free Documentation License, Version 1.3 or +any later version published by the Free Software Foundation; with no +Invariant Sections, the Front-Cover texts being (a) (see below), and +with the Back-Cover Texts being (b) (see below). A copy of the +license is included in the section entitled "GNU +Free Documentation License". + +(a) The FSF's Front-Cover Text is: + +A GNU Manual + +(b) The FSF's Back-Cover Text is: + +You have freedom to copy and modify this GNU Manual, like GNU + software. Copies published by the Free Software Foundation raise + funds for GNU development. --> +<!-- Created by GNU Texinfo 5.1, http://www.gnu.org/software/texinfo/ --> +<head> +<title>Installing GCC: Configuration</title> + +<meta name="description" content="Installing GCC: Configuration"> +<meta name="keywords" content="Installing GCC: Configuration"> +<meta name="resource-type" content="document"> +<meta name="distribution" content="global"> +<meta name="Generator" content="makeinfo"> +<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> +<style type="text/css"> +<!-- +a.summary-letter {text-decoration: none} +blockquote.smallquotation {font-size: smaller} +div.display {margin-left: 3.2em} +div.example {margin-left: 3.2em} +div.indentedblock {margin-left: 3.2em} +div.lisp {margin-left: 3.2em} +div.smalldisplay {margin-left: 3.2em} +div.smallexample {margin-left: 3.2em} +div.smallindentedblock {margin-left: 3.2em; font-size: smaller} +div.smalllisp {margin-left: 3.2em} +kbd {font-style:oblique} +pre.display {font-family: inherit} +pre.format {font-family: inherit} +pre.menu-comment {font-family: serif} +pre.menu-preformatted {font-family: serif} +pre.smalldisplay {font-family: inherit; font-size: smaller} +pre.smallexample {font-size: smaller} +pre.smallformat {font-family: inherit; font-size: smaller} +pre.smalllisp {font-size: smaller} +span.nocodebreak {white-space:nowrap} +span.nolinebreak {white-space:nowrap} +span.roman {font-family:serif; font-weight:normal} +span.sansserif {font-family:sans-serif; font-weight:normal} +ul.no-bullet {list-style: none} +--> +</style> + + +</head> + +<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000"> +<h1 class="settitle" align="center">Installing GCC: Configuration</h1> + + + + + + + + + + + + + + + + + + + + + + +<a name="index-Configuration"></a> +<a name="index-Installing-GCC_003a-Configuration"></a> + +<p>Like most GNU software, GCC must be configured before it can be built. +This document describes the recommended configuration procedure +for both native and cross targets. +</p> +<p>We use <var>srcdir</var> to refer to the toplevel source directory for +GCC; we use <var>objdir</var> to refer to the toplevel build/object directory. +</p> +<p>If you obtained the sources by cloning the repository, <var>srcdir</var> +must refer to the top <samp>gcc</samp> directory, the one where the +<samp>MAINTAINERS</samp> file can be found, and not its <samp>gcc</samp> +subdirectory, otherwise the build will fail. +</p> +<p>If either <var>srcdir</var> or <var>objdir</var> is located on an automounted NFS +file system, the shell’s built-in <code>pwd</code> command will return +temporary pathnames. Using these can lead to various sorts of build +problems. To avoid this issue, set the <code>PWDCMD</code> environment +variable to an automounter-aware <code>pwd</code> command, e.g., +<code>pawd</code> or ‘<samp>amq -w</samp>’, during the configuration and build +phases. +</p> +<p>First, we <strong>highly</strong> recommend that GCC be built into a +separate directory from the sources which does <strong>not</strong> reside +within the source tree. This is how we generally build GCC; building +where <var>srcdir</var> == <var>objdir</var> should still work, but doesn’t +get extensive testing; building where <var>objdir</var> is a subdirectory +of <var>srcdir</var> is unsupported. +</p> +<p>If you have previously built GCC in the same directory for a +different target machine, do ‘<samp>make distclean</samp>’ to delete all files +that might be invalid. One of the files this deletes is <samp>Makefile</samp>; +if ‘<samp>make distclean</samp>’ complains that <samp>Makefile</samp> does not exist +or issues a message like “don’t know how to make distclean” it probably +means that the directory is already suitably clean. However, with the +recommended method of building in a separate <var>objdir</var>, you should +simply use a different <var>objdir</var> for each target. +</p> +<p>Second, when configuring a native system, either <code>cc</code> or +<code>gcc</code> must be in your path or you must set <code>CC</code> in +your environment before running configure. Otherwise the configuration +scripts may fail. +</p> + +<p>To configure GCC: +</p> +<div class="smallexample"> +<pre class="smallexample">% mkdir <var>objdir</var> +% cd <var>objdir</var> +% <var>srcdir</var>/configure [<var>options</var>] [<var>target</var>] +</pre></div> + +<a name="Distributor-options"></a> +<h3 class="heading">Distributor options</h3> + +<p>If you will be distributing binary versions of GCC, with modifications +to the source code, you should use the options described in this +section to make clear that your version contains modifications. +</p> +<dl compact="compact"> +<dt><code>--with-pkgversion=<var>version</var></code></dt> +<dd><p>Specify a string that identifies your package. You may wish +to include a build number or build date. This version string will be +included in the output of <code>gcc --version</code>. This suffix does +not replace the default version string, only the ‘<samp>GCC</samp>’ part. +</p> +<p>The default value is ‘<samp>GCC</samp>’. +</p> +</dd> +<dt><code>--with-bugurl=<var>url</var></code></dt> +<dd><p>Specify the URL that users should visit if they wish to report a bug. +You are of course welcome to forward bugs reported to you to the FSF, +if you determine that they are not bugs in your modifications. +</p> +<p>The default value refers to the FSF’s GCC bug tracker. +</p> +</dd> +<dt><code>--with-documentation-root-url=<var>url</var></code></dt> +<dd><p>Specify the URL root that contains GCC option documentation. The <var>url</var> +should end with a <code>/</code> character. +</p> +<p>The default value is <a href="https://gcc.gnu.org/onlinedocs/">https://gcc.gnu.org/onlinedocs/</a>. +</p> +</dd> +<dt><code>--with-changes-root-url=<var>url</var></code></dt> +<dd><p>Specify the URL root that contains information about changes in GCC +releases like <code>gcc-<var>version</var>/changes.html</code>. +The <var>url</var> should end with a <code>/</code> character. +</p> +<p>The default value is <a href="https://gcc.gnu.org/">https://gcc.gnu.org/</a>. +</p> +</dd> +</dl> + +<a name="Host_002c-Build-and-Target-specification"></a> +<h3 class="heading">Host, Build and Target specification</h3> + +<p>Specify the host, build and target machine configurations. You do this +when you run the <samp>configure</samp> script. +</p> +<p>The <em>build</em> machine is the system which you are using, the +<em>host</em> machine is the system where you want to run the resulting +compiler (normally the build machine), and the <em>target</em> machine is +the system for which you want the compiler to generate code. +</p> +<p>If you are building a compiler to produce code for the machine it runs +on (a native compiler), you normally do not need to specify any operands +to <samp>configure</samp>; it will try to guess the type of machine you are on +and use that as the build, host and target machines. So you don’t need +to specify a configuration when building a native compiler unless +<samp>configure</samp> cannot figure out what your configuration is or guesses +wrong. +</p> +<p>In those cases, specify the build machine’s <em>configuration name</em> +with the <samp>--host</samp> option; the host and target will default to be +the same as the host machine. +</p> +<p>Here is an example: +</p> +<div class="smallexample"> +<pre class="smallexample">./configure --host=x86_64-pc-linux-gnu +</pre></div> + +<p>A configuration name may be canonical or it may be more or less +abbreviated (<samp>config.sub</samp> script produces canonical versions). +</p> +<p>A canonical configuration name has three parts, separated by dashes. +It looks like this: ‘<samp><var>cpu</var>-<var>company</var>-<var>system</var></samp>’. +</p> +<p>Here are the possible CPU types: +</p> +<blockquote> +<p>aarch64, aarch64_be, alpha, alpha64, amdgcn, arc, arceb, arm, armeb, avr, bfin, +bpf, cris, csky, epiphany, fido, fr30, frv, ft32, h8300, hppa, hppa2.0, +hppa64, i486, i686, ia64, iq2000, lm32, loongarch64, m32c, m32r, m32rle, m68k, +mcore, microblaze, microblazeel, mips, mips64, mips64el, mips64octeon, +mips64orion, mips64vr, mipsel, mipsisa32, mipsisa32r2, mipsisa64, mipsisa64r2, +mipsisa64r2el, mipsisa64sb1, mipsisa64sr71k, mipstx39, mmix, mn10300, moxie, +msp430, nds32be, nds32le, nios2, nvptx, or1k, pdp11, powerpc, powerpc64, +powerpc64le, powerpcle, pru, riscv32, riscv32be, riscv64, riscv64be, rl78, rx, +s390, s390x, sh, shle, sparc, sparc64, tic6x, v850, +v850e, v850e1, vax, visium, x86_64, xstormy16, xtensa +</p></blockquote> + +<p>Here is a list of system types: +</p> +<blockquote> +<p>aix<var>version</var>, amdhsa, aout, cygwin, darwin<var>version</var>, +eabi, eabialtivec, eabisim, eabisimaltivec, elf, elf32, +elfbare, elfoabi, freebsd<var>version</var>, gnu, hpux, hpux<var>version</var>, +kfreebsd-gnu, kopensolaris-gnu, linux-androideabi, linux-gnu, +linux-gnu_altivec, linux-musl, linux-uclibc, lynxos, mingw32, mingw32crt, +mmixware, msdosdjgpp, netbsd, netbsdelf<var>version</var>, nto-qnx, openbsd, +rtems, solaris<var>version</var>, symbianelf, tpf, uclinux, uclinux_eabi, vms, +vxworks, vxworksae, vxworksmils +</p></blockquote> + +<a name="Options-specification"></a> +<h3 class="heading">Options specification</h3> + +<p>Use <var>options</var> to override several configure time options for +GCC. A list of supported <var>options</var> follows; ‘<samp>configure +--help</samp>’ may list other options, but those not listed below may not +work and should not normally be used. +</p> +<p>Note that each <samp>--enable</samp> option has a corresponding +<samp>--disable</samp> option and that each <samp>--with</samp> option has a +corresponding <samp>--without</samp> option. +</p> +<dl compact="compact"> +<dt><code>--prefix=<var>dirname</var></code></dt> +<dd><p>Specify the toplevel installation +directory. This is the recommended way to install the tools into a directory +other than the default. The toplevel installation directory defaults to +<samp>/usr/local</samp>. +</p> +<p>We <strong>highly</strong> recommend against <var>dirname</var> being the same or a +subdirectory of <var>objdir</var> or vice versa. If specifying a directory +beneath a user’s home directory tree, some shells will not expand +<var>dirname</var> correctly if it contains the ‘<samp>~</samp>’ metacharacter; use +<code>$HOME</code> instead. +</p> +<p>The following standard <code>autoconf</code> options are supported. Normally you +should not need to use these options. +</p><dl compact="compact"> +<dt><code>--exec-prefix=<var>dirname</var></code></dt> +<dd><p>Specify the toplevel installation directory for architecture-dependent +files. The default is <samp><var>prefix</var></samp>. +</p> +</dd> +<dt><code>--bindir=<var>dirname</var></code></dt> +<dd><p>Specify the installation directory for the executables called by users +(such as <code>gcc</code> and <code>g++</code>). The default is +<samp><var>exec-prefix</var>/bin</samp>. +</p> +</dd> +<dt><code>--libdir=<var>dirname</var></code></dt> +<dd><p>Specify the installation directory for object code libraries and +internal data files of GCC. The default is <samp><var>exec-prefix</var>/lib</samp>. +</p> +</dd> +<dt><code>--libexecdir=<var>dirname</var></code></dt> +<dd><p>Specify the installation directory for internal executables of GCC. +The default is <samp><var>exec-prefix</var>/libexec</samp>. +</p> +</dd> +<dt><code>--with-slibdir=<var>dirname</var></code></dt> +<dd><p>Specify the installation directory for the shared libgcc library. The +default is <samp><var>libdir</var></samp>. +</p> +</dd> +<dt><code>--datarootdir=<var>dirname</var></code></dt> +<dd><p>Specify the root of the directory tree for read-only architecture-independent +data files referenced by GCC. The default is <samp><var>prefix</var>/share</samp>. +</p> +</dd> +<dt><code>--infodir=<var>dirname</var></code></dt> +<dd><p>Specify the installation directory for documentation in info format. +The default is <samp><var>datarootdir</var>/info</samp>. +</p> +</dd> +<dt><code>--datadir=<var>dirname</var></code></dt> +<dd><p>Specify the installation directory for some architecture-independent +data files referenced by GCC. The default is <samp><var>datarootdir</var></samp>. +</p> +</dd> +<dt><code>--docdir=<var>dirname</var></code></dt> +<dd><p>Specify the installation directory for documentation files (other +than Info) for GCC. The default is <samp><var>datarootdir</var>/doc</samp>. +</p> +</dd> +<dt><code>--htmldir=<var>dirname</var></code></dt> +<dd><p>Specify the installation directory for HTML documentation files. +The default is <samp><var>docdir</var></samp>. +</p> +</dd> +<dt><code>--pdfdir=<var>dirname</var></code></dt> +<dd><p>Specify the installation directory for PDF documentation files. +The default is <samp><var>docdir</var></samp>. +</p> +</dd> +<dt><code>--mandir=<var>dirname</var></code></dt> +<dd><p>Specify the installation directory for manual pages. The default is +<samp><var>datarootdir</var>/man</samp>. (Note that the manual pages are only extracts +from the full GCC manuals, which are provided in Texinfo format. The manpages +are derived by an automatic conversion process from parts of the full +manual.) +</p> +</dd> +<dt><code>--with-gxx-include-dir=<var>dirname</var></code></dt> +<dd><p>Specify +the installation directory for G++ header files. The default depends +on other configuration options, and differs between cross and native +configurations. +</p> +</dd> +<dt><code>--with-specs=<var>specs</var></code></dt> +<dd><p>Specify additional command line driver SPECS. +This can be useful if you need to turn on a non-standard feature by +default without modifying the compiler’s source code, for instance +<samp>--with-specs=%{!fcommon:%{!fno-common:-fno-common}}</samp>. +See “Spec Files” in the main manual +</p> +</dd> +</dl> + +</dd> +<dt><code>--program-prefix=<var>prefix</var></code></dt> +<dd><p>GCC supports some transformations of the names of its programs when +installing them. This option prepends <var>prefix</var> to the names of +programs to install in <var>bindir</var> (see above). For example, specifying +<samp>--program-prefix=foo-</samp> would result in ‘<samp>gcc</samp>’ +being installed as <samp>/usr/local/bin/foo-gcc</samp>. +</p> +</dd> +<dt><code>--program-suffix=<var>suffix</var></code></dt> +<dd><p>Appends <var>suffix</var> to the names of programs to install in <var>bindir</var> +(see above). For example, specifying <samp>--program-suffix=-3.1</samp> +would result in ‘<samp>gcc</samp>’ being installed as +<samp>/usr/local/bin/gcc-3.1</samp>. +</p> +</dd> +<dt><code>--program-transform-name=<var>pattern</var></code></dt> +<dd><p>Applies the ‘<samp>sed</samp>’ script <var>pattern</var> to be applied to the names +of programs to install in <var>bindir</var> (see above). <var>pattern</var> has to +consist of one or more basic ‘<samp>sed</samp>’ editing commands, separated by +semicolons. For example, if you want the ‘<samp>gcc</samp>’ program name to be +transformed to the installed program <samp>/usr/local/bin/myowngcc</samp> and +the ‘<samp>g++</samp>’ program name to be transformed to +<samp>/usr/local/bin/gspecial++</samp> without changing other program names, +you could use the pattern +<samp>--program-transform-name='s/^gcc$/myowngcc/; s/^g++$/gspecial++/'</samp> +to achieve this effect. +</p> +<p>All three options can be combined and used together, resulting in more +complex conversion patterns. As a basic rule, <var>prefix</var> (and +<var>suffix</var>) are prepended (appended) before further transformations +can happen with a special transformation script <var>pattern</var>. +</p> +<p>As currently implemented, this option only takes effect for native +builds; cross compiler binaries’ names are not transformed even when a +transformation is explicitly asked for by one of these options. +</p> +<p>For native builds, some of the installed programs are also installed +with the target alias in front of their name, as in +‘<samp>i686-pc-linux-gnu-gcc</samp>’. All of the above transformations happen +before the target alias is prepended to the name—so, specifying +<samp>--program-prefix=foo-</samp> and <samp>program-suffix=-3.1</samp>, the +resulting binary would be installed as +<samp>/usr/local/bin/i686-pc-linux-gnu-foo-gcc-3.1</samp>. +</p> +<p>As a last shortcoming, none of the installed Ada programs are +transformed yet, which will be fixed in some time. +</p> +</dd> +<dt><code>--with-local-prefix=<var>dirname</var></code></dt> +<dd><p>Specify the +installation directory for local include files. The default is +<samp>/usr/local</samp>. Specify this option if you want the compiler to +search directory <samp><var>dirname</var>/include</samp> for locally installed +header files <em>instead</em> of <samp>/usr/local/include</samp>. +</p> +<p>You should specify <samp>--with-local-prefix</samp> <strong>only</strong> if your +site has a different convention (not <samp>/usr/local</samp>) for where to put +site-specific files. +</p> +<p>The default value for <samp>--with-local-prefix</samp> is <samp>/usr/local</samp> +regardless of the value of <samp>--prefix</samp>. Specifying +<samp>--prefix</samp> has no effect on which directory GCC searches for +local header files. This may seem counterintuitive, but actually it is +logical. +</p> +<p>The purpose of <samp>--prefix</samp> is to specify where to <em>install +GCC</em>. The local header files in <samp>/usr/local/include</samp>—if you put +any in that directory—are not part of GCC. They are part of other +programs—perhaps many others. (GCC installs its own header files in +another directory which is based on the <samp>--prefix</samp> value.) +</p> +<p>Both the local-prefix include directory and the GCC-prefix include +directory are part of GCC’s “system include” directories. Although these +two directories are not fixed, they need to be searched in the proper +order for the correct processing of the include_next directive. The +local-prefix include directory is searched before the GCC-prefix +include directory. Another characteristic of system include directories +is that pedantic warnings are turned off for headers in these directories. +</p> +<p>Some autoconf macros add <samp>-I <var>directory</var></samp> options to the +compiler command line, to ensure that directories containing installed +packages’ headers are searched. When <var>directory</var> is one of GCC’s +system include directories, GCC will ignore the option so that system +directories continue to be processed in the correct order. This +may result in a search order different from what was specified but the +directory will still be searched. +</p> +<p>GCC automatically searches for ordinary libraries using +<code>GCC_EXEC_PREFIX</code>. Thus, when the same installation prefix is +used for both GCC and packages, GCC will automatically search for +both headers and libraries. This provides a configuration that is +easy to use. GCC behaves in a manner similar to that when it is +installed as a system compiler in <samp>/usr</samp>. +</p> +<p>Sites that need to install multiple versions of GCC may not want to +use the above simple configuration. It is possible to use the +<samp>--program-prefix</samp>, <samp>--program-suffix</samp> and +<samp>--program-transform-name</samp> options to install multiple versions +into a single directory, but it may be simpler to use different prefixes +and the <samp>--with-local-prefix</samp> option to specify the location of the +site-specific files for each version. It will then be necessary for +users to specify explicitly the location of local site libraries +(e.g., with <code>LIBRARY_PATH</code>). +</p> +<p>The same value can be used for both <samp>--with-local-prefix</samp> and +<samp>--prefix</samp> provided it is not <samp>/usr</samp>. This can be used +to avoid the default search of <samp>/usr/local/include</samp>. +</p> +<p><strong>Do not</strong> specify <samp>/usr</samp> as the <samp>--with-local-prefix</samp>! +The directory you use for <samp>--with-local-prefix</samp> <strong>must not</strong> +contain any of the system’s standard header files. If it did contain +them, certain programs would be miscompiled (including GNU Emacs, on +certain targets), because this would override and nullify the header +file corrections made by the <code>fixincludes</code> script. +</p> +<p>Indications are that people who use this option use it based on mistaken +ideas of what it is for. People use it as if it specified where to +install part of GCC. Perhaps they make this assumption because +installing GCC creates the directory. +</p> +</dd> +<dt><code>--with-gcc-major-version-only</code></dt> +<dd><p>Specifies that GCC should use only the major number rather than +<var>major</var>.<var>minor</var>.<var>patchlevel</var> in filesystem paths. +</p> +</dd> +<dt><code>--with-native-system-header-dir=<var>dirname</var></code></dt> +<dd><p>Specifies that <var>dirname</var> is the directory that contains native system +header files, rather than <samp>/usr/include</samp>. This option is most useful +if you are creating a compiler that should be isolated from the system +as much as possible. It is most commonly used with the +<samp>--with-sysroot</samp> option and will cause GCC to search +<var>dirname</var> inside the system root specified by that option. +</p> +</dd> +<dt><code>--enable-shared[=<var>package</var>[,…]]</code></dt> +<dd><p>Build shared versions of libraries, if shared libraries are supported on +the target platform. Unlike GCC 2.95.x and earlier, shared libraries +are enabled by default on all platforms that support shared libraries. +</p> +<p>If a list of packages is given as an argument, build shared libraries +only for the listed packages. For other packages, only static libraries +will be built. Package names currently recognized in the GCC tree are +‘<samp>libgcc</samp>’ (also known as ‘<samp>gcc</samp>’), ‘<samp>libstdc++</samp>’ (not +‘<samp>libstdc++-v3</samp>’), ‘<samp>libffi</samp>’, ‘<samp>zlib</samp>’, ‘<samp>boehm-gc</samp>’, +‘<samp>ada</samp>’, ‘<samp>libada</samp>’, ‘<samp>libgo</samp>’, ‘<samp>libobjc</samp>’, and ‘<samp>libphobos</samp>’. +Note ‘<samp>libiberty</samp>’ does not support shared libraries at all. +</p> +<p>Use <samp>--disable-shared</samp> to build only static libraries. Note that +<samp>--disable-shared</samp> does not accept a list of package names as +argument, only <samp>--enable-shared</samp> does. +</p> +<p>Contrast with <samp>--enable-host-shared</samp>, which affects <em>host</em> +code. +</p> +</dd> +<dt><code>--enable-host-shared</code></dt> +<dd><p>Specify that the <em>host</em> code should be built into position-independent +machine code (with -fPIC), allowing it to be used within shared libraries, +but yielding a slightly slower compiler. +</p> +<p>This option is required when building the libgccjit.so library. +</p> +<p>Contrast with <samp>--enable-shared</samp>, which affects <em>target</em> +libraries. +</p> +</dd> +<dt><code><a name="with-gnu-as"></a>--with-gnu-as</code></dt> +<dd><p>Specify that the compiler should assume that the +assembler it finds is the GNU assembler. However, this does not modify +the rules to find an assembler and will result in confusion if the +assembler found is not actually the GNU assembler. (Confusion may also +result if the compiler finds the GNU assembler but has not been +configured with <samp>--with-gnu-as</samp>.) If you have more than one +assembler installed on your system, you may want to use this option in +connection with <samp>--with-as=<var>pathname</var></samp> or +<samp>--with-build-time-tools=<var>pathname</var></samp>. +</p> +<p>The following systems are the only ones where it makes a difference +whether you use the GNU assembler. On any other system, +<samp>--with-gnu-as</samp> has no effect. +</p> +<ul> +<li> ‘<samp>hppa1.0-<var>any</var>-<var>any</var></samp>’ +</li><li> ‘<samp>hppa1.1-<var>any</var>-<var>any</var></samp>’ +</li><li> ‘<samp>*-*-solaris2.11</samp>’ +</li></ul> + +</dd> +<dt><code><a name="with-as"></a>--with-as=<var>pathname</var></code></dt> +<dd><p>Specify that the compiler should use the assembler pointed to by +<var>pathname</var>, rather than the one found by the standard rules to find +an assembler, which are: +</p><ul> +<li> Unless GCC is being built with a cross compiler, check the +<samp><var>libexec</var>/gcc/<var>target</var>/<var>version</var></samp> directory. +<var>libexec</var> defaults to <samp><var>exec-prefix</var>/libexec</samp>; +<var>exec-prefix</var> defaults to <var>prefix</var>, which +defaults to <samp>/usr/local</samp> unless overridden by the +<samp>--prefix=<var>pathname</var></samp> switch described above. <var>target</var> +is the target system triple, such as ‘<samp>sparc-sun-solaris2.11</samp>’, and +<var>version</var> denotes the GCC version, such as 3.0. + +</li><li> If the target system is the same that you are building on, check +operating system specific directories. + +</li><li> Check in the <code>PATH</code> for a tool whose name is prefixed by the +target system triple. + +</li><li> Check in the <code>PATH</code> for a tool whose name is not prefixed by the +target system triple, if the host and target system triple are +the same (in other words, we use a host tool if it can be used for +the target as well). +</li></ul> + +<p>You may want to use <samp>--with-as</samp> if no assembler +is installed in the directories listed above, or if you have multiple +assemblers installed and want to choose one that is not found by the +above rules. +</p> +</dd> +<dt><code><a name="with-gnu-ld"></a>--with-gnu-ld</code></dt> +<dd><p>Same as <a href="#with-gnu-as"><samp>--with-gnu-as</samp></a> +but for the linker. +</p> +</dd> +<dt><code>--with-ld=<var>pathname</var></code></dt> +<dd><p>Same as <a href="#with-as"><samp>--with-as</samp></a> +but for the linker. +</p> +</dd> +<dt><code>--with-dsymutil=<var>pathname</var></code></dt> +<dd><p>Same as <a href="#with-as"><samp>--with-as</samp></a> +but for the debug linker (only used on Darwin platforms so far). +</p> +</dd> +<dt><code>--with-tls=<var>dialect</var></code></dt> +<dd><p>Specify the default TLS dialect, for systems were there is a choice. +For ARM targets, possible values for <var>dialect</var> are <code>gnu</code> or +<code>gnu2</code>, which select between the original GNU dialect and the GNU TLS +descriptor-based dialect. +</p> +</dd> +<dt><code>--enable-multiarch</code></dt> +<dd><p>Specify whether to enable or disable multiarch support. The default is +to check for glibc start files in a multiarch location, and enable it +if the files are found. The auto detection is enabled for native builds, +and for cross builds configured with <samp>--with-sysroot</samp>, and without +<samp>--with-native-system-header-dir</samp>. +More documentation about multiarch can be found at +<a href="https://wiki.debian.org/Multiarch">https://wiki.debian.org/Multiarch</a>. +</p> +</dd> +<dt><code>--enable-sjlj-exceptions</code></dt> +<dd><p>Force use of the <code>setjmp</code>/<code>longjmp</code>-based scheme for exceptions. +‘<samp>configure</samp>’ ordinarily picks the correct value based on the platform. +Only use this option if you are sure you need a different setting. +</p> +</dd> +<dt><code>--enable-vtable-verify</code></dt> +<dd><p>Specify whether to enable or disable the vtable verification feature. +Enabling this feature causes libstdc++ to be built with its virtual calls +in verifiable mode. This means that, when linked with libvtv, every +virtual call in libstdc++ will verify the vtable pointer through which the +call will be made before actually making the call. If not linked with libvtv, +the verifier will call stub functions (in libstdc++ itself) and do nothing. +If vtable verification is disabled, then libstdc++ is not built with its +virtual calls in verifiable mode at all. However the libvtv library will +still be built (see <samp>--disable-libvtv</samp> to turn off building libvtv). +<samp>--disable-vtable-verify</samp> is the default. +</p> +</dd> +<dt><code>--disable-gcov</code></dt> +<dd><p>Specify that the run-time library used for coverage analysis +and associated host tools should not be built. +</p> +</dd> +<dt><code>--disable-multilib</code></dt> +<dd><p>Specify that multiple target +libraries to support different target variants, calling +conventions, etc. should not be built. The default is to build a +predefined set of them. +</p> +<p>Some targets provide finer-grained control over which multilibs are built +(e.g., <samp>--disable-softfloat</samp>): +</p><dl compact="compact"> +<dt><code>arm-*-*</code></dt> +<dd><p>fpu, 26bit, underscore, interwork, biendian, nofmult. +</p> +</dd> +<dt><code>m68*-*-*</code></dt> +<dd><p>softfloat, m68881, m68000, m68020. +</p> +</dd> +<dt><code>mips*-*-*</code></dt> +<dd><p>single-float, biendian, softfloat. +</p> +</dd> +<dt><code>msp430-*-*</code></dt> +<dd><p>no-exceptions +</p> +</dd> +<dt><code>powerpc*-*-*, rs6000*-*-*</code></dt> +<dd><p>aix64, pthread, softfloat, powercpu, powerpccpu, powerpcos, biendian, +sysv, aix. +</p> +</dd> +</dl> + +</dd> +<dt><code>--with-multilib-list=<var>list</var></code></dt> +<dt><code>--without-multilib-list</code></dt> +<dd><p>Specify what multilibs to build. <var>list</var> is a comma separated list of +values, possibly consisting of a single value. Currently only implemented +for aarch64*-*-*, arm*-*-*, loongarch64-*-*, riscv*-*-*, sh*-*-* and +x86-64-*-linux*. The accepted values and meaning for each target is given +below. +</p> +<dl compact="compact"> +<dt><code>aarch64*-*-*</code></dt> +<dd><p><var>list</var> is a comma separated list of <code>ilp32</code>, and <code>lp64</code> +to enable ILP32 and LP64 run-time libraries, respectively. If +<var>list</var> is empty, then there will be no multilibs and only the +default run-time library will be built. If <var>list</var> is +<code>default</code> or –with-multilib-list= is not specified, then the +default set of libraries is selected based on the value of +<samp>--target</samp>. +</p> +</dd> +<dt><code>arm*-*-*</code></dt> +<dd><p><var>list</var> is a comma separated list of <code>aprofile</code> and +<code>rmprofile</code> to build multilibs for A or R and M architecture +profiles respectively. Note that, due to some limitation of the current +multilib framework, using the combined <code>aprofile,rmprofile</code> +multilibs selects in some cases a less optimal multilib than when using +the multilib profile for the architecture targetted. The special value +<code>default</code> is also accepted and is equivalent to omitting the +option, i.e., only the default run-time library will be enabled. +</p> +<p><var>list</var> may instead contain <code>@name</code>, to use the multilib +configuration Makefile fragment <samp>name</samp> in <samp>gcc/config/arm</samp> in +the source tree (it is part of the corresponding sources, after all). +It is recommended, but not required, that files used for this purpose to +be named starting with <samp>t-ml-</samp>, to make their intended purpose +self-evident, in line with GCC conventions. Such files enable custom, +user-chosen multilib lists to be configured. Whether multiple such +files can be used together depends on the contents of the supplied +files. See <samp>gcc/config/arm/t-multilib</samp> and its supplementary +<samp>gcc/config/arm/t-*profile</samp> files for an example of what such +Makefile fragments might look like for this version of GCC. The macros +expected to be defined in these fragments are not stable across GCC +releases, so make sure they define the <code>MULTILIB</code>-related macros +expected by the version of GCC you are building. +See “Target Makefile Fragments” in the internals manual. +</p> +<p>The table below gives the combination of ISAs, architectures, FPUs and +floating-point ABIs for which multilibs are built for each predefined +profile. The union of these options is considered when specifying both +<code>aprofile</code> and <code>rmprofile</code>. +</p> +<table> +<tr><td width="15%">Option</td><td width="28%">aprofile</td><td width="30%">rmprofile</td></tr> +<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> +<tr><td width="15%">Architectures<br><br><br><br><br><br></td><td width="28%">default architecture<br> +<code>-march=armv7-a</code><br> +<code>-march=armv7ve</code><br> +<code>-march=armv8-a</code><br><br><br></td><td width="30%">default architecture<br> +<code>-march=armv6s-m</code><br> +<code>-march=armv7-m</code><br> +<code>-march=armv7e-m</code><br> +<code>-march=armv8-m.base</code><br> +<code>-march=armv8-m.main</code><br> +<code>-march=armv7</code></td></tr> +<tr><td width="15%">FPUs<br><br><br><br><br></td><td width="28%">none<br> +<code>-mfpu=vfpv3-d16</code><br> +<code>-mfpu=neon</code><br> +<code>-mfpu=vfpv4-d16</code><br> +<code>-mfpu=neon-vfpv4</code><br> +<code>-mfpu=neon-fp-armv8</code></td><td width="30%">none<br> +<code>-mfpu=vfpv3-d16</code><br> +<code>-mfpu=fpv4-sp-d16</code><br> +<code>-mfpu=fpv5-sp-d16</code><br> +<code>-mfpu=fpv5-d16</code><br></td></tr> +<tr><td width="15%">floating-point ABIs<br><br></td><td width="28%"><code>-mfloat-abi=soft</code><br> +<code>-mfloat-abi=softfp</code><br> +<code>-mfloat-abi=hard</code></td><td width="30%"><code>-mfloat-abi=soft</code><br> +<code>-mfloat-abi=softfp</code><br> +<code>-mfloat-abi=hard</code></td></tr> +</table> + +</dd> +<dt><code>loongarch*-*-*</code></dt> +<dd><p><var>list</var> is a comma-separated list of the following ABI identifiers: +<code>lp64d[/base]</code> <code>lp64f[/base]</code> <code>lp64d[/base]</code>, where the +<code>/base</code> suffix may be omitted, to enable their respective run-time +libraries. If <var>list</var> is empty or <code>default</code>, +or if <samp>--with-multilib-list</samp> is not specified, then the default ABI +as specified by <samp>--with-abi</samp> or implied by <samp>--target</samp> is selected. +</p> +</dd> +<dt><code>riscv*-*-*</code></dt> +<dd><p><var>list</var> is a single ABI name. The target architecture must be either +<code>rv32gc</code> or <code>rv64gc</code>. This will build a single multilib for the +specified architecture and ABI pair. If <code>--with-multilib-list</code> is not +given, then a default set of multilibs is selected based on the value of +<samp>--target</samp>. This is usually a large set of multilibs. +</p> +</dd> +<dt><code>sh*-*-*</code></dt> +<dd><p><var>list</var> is a comma separated list of CPU names. These must be of the +form <code>sh*</code> or <code>m*</code> (in which case they match the compiler option +for that processor). The list should not contain any endian options - +these are handled by <samp>--with-endian</samp>. +</p> +<p>If <var>list</var> is empty, then there will be no multilibs for extra +processors. The multilib for the secondary endian remains enabled. +</p> +<p>As a special case, if an entry in the list starts with a <code>!</code> +(exclamation point), then it is added to the list of excluded multilibs. +Entries of this sort should be compatible with ‘<samp>MULTILIB_EXCLUDES</samp>’ +(once the leading <code>!</code> has been stripped). +</p> +<p>If <samp>--with-multilib-list</samp> is not given, then a default set of +multilibs is selected based on the value of <samp>--target</samp>. This is +usually the complete set of libraries, but some targets imply a more +specialized subset. +</p> +<p>Example 1: to configure a compiler for SH4A only, but supporting both +endians, with little endian being the default: +</p><div class="smallexample"> +<pre class="smallexample">--with-cpu=sh4a --with-endian=little,big --with-multilib-list= +</pre></div> + +<p>Example 2: to configure a compiler for both SH4A and SH4AL-DSP, but with +only little endian SH4AL: +</p><div class="smallexample"> +<pre class="smallexample">--with-cpu=sh4a --with-endian=little,big \ +--with-multilib-list=sh4al,!mb/m4al +</pre></div> + +</dd> +<dt><code>x86-64-*-linux*</code></dt> +<dd><p><var>list</var> is a comma separated list of <code>m32</code>, <code>m64</code> and +<code>mx32</code> to enable 32-bit, 64-bit and x32 run-time libraries, +respectively. If <var>list</var> is empty, then there will be no multilibs +and only the default run-time library will be enabled. +</p> +<p>If <samp>--with-multilib-list</samp> is not given, then only 32-bit and +64-bit run-time libraries will be enabled. +</p></dd> +</dl> + +</dd> +<dt><code>--with-multilib-generator=<var>config</var></code></dt> +<dd><p>Specify what multilibs to build. <var>config</var> is a semicolon separated list of +values, possibly consisting of a single value. Currently only implemented +for riscv*-*-elf*. The accepted values and meanings are given below. +</p> + +<p>Every config is constructed with four components: architecture string, ABI, +reuse rule with architecture string and reuse rule with sub-extension. +</p> +<p>Example 1: Add multi-lib suppport for rv32i with ilp32. +</p><div class="smallexample"> +<pre class="smallexample">rv32i-ilp32-- +</pre></div> + +<p>Example 2: Add multi-lib suppport for rv32i with ilp32 and rv32imafd with ilp32. +</p><div class="smallexample"> +<pre class="smallexample">rv32i-ilp32--;rv32imafd-ilp32-- +</pre></div> + +<p>Example 3: Add multi-lib suppport for rv32i with ilp32; rv32im with ilp32 and +rv32ic with ilp32 will reuse this multi-lib set. +</p><div class="smallexample"> +<pre class="smallexample">rv32i-ilp32-rv32im-c +</pre></div> + +<p>Example 4: Add multi-lib suppport for rv64ima with lp64; rv64imaf with lp64, +rv64imac with lp64 and rv64imafc with lp64 will reuse this multi-lib set. +</p><div class="smallexample"> +<pre class="smallexample">rv64ima-lp64--f,c,fc +</pre></div> + +<p><samp>--with-multilib-generator</samp> have an optional configuration argument +<samp>--cmodel=val</samp> for code model, this option will expand with other +config options, <var>val</var> is a comma separated list of possible code model, +currently we support medlow and medany. +</p> +<p>Example 5: Add multi-lib suppport for rv64ima with lp64; rv64ima with lp64 and +medlow code model +</p><div class="smallexample"> +<pre class="smallexample">rv64ima-lp64--;--cmodel=medlow +</pre></div> + +<p>Example 6: Add multi-lib suppport for rv64ima with lp64; rv64ima with lp64 and +medlow code model; rv64ima with lp64 and medany code model +</p><div class="smallexample"> +<pre class="smallexample">rv64ima-lp64--;--cmodel=medlow,medany +</pre></div> + +</dd> +<dt><code>--with-endian=<var>endians</var></code></dt> +<dd><p>Specify what endians to use. +Currently only implemented for sh*-*-*. +</p> +<p><var>endians</var> may be one of the following: +</p><dl compact="compact"> +<dt><code>big</code></dt> +<dd><p>Use big endian exclusively. +</p></dd> +<dt><code>little</code></dt> +<dd><p>Use little endian exclusively. +</p></dd> +<dt><code>big,little</code></dt> +<dd><p>Use big endian by default. Provide a multilib for little endian. +</p></dd> +<dt><code>little,big</code></dt> +<dd><p>Use little endian by default. Provide a multilib for big endian. +</p></dd> +</dl> + +</dd> +<dt><code>--enable-threads</code></dt> +<dd><p>Specify that the target +supports threads. This affects the Objective-C compiler and runtime +library, and exception handling for other languages like C++. +On some systems, this is the default. +</p> +<p>In general, the best (and, in many cases, the only known) threading +model available will be configured for use. Beware that on some +systems, GCC has not been taught what threading models are generally +available for the system. In this case, <samp>--enable-threads</samp> is an +alias for <samp>--enable-threads=single</samp>. +</p> +</dd> +<dt><code>--disable-threads</code></dt> +<dd><p>Specify that threading support should be disabled for the system. +This is an alias for <samp>--enable-threads=single</samp>. +</p> +</dd> +<dt><code>--enable-threads=<var>lib</var></code></dt> +<dd><p>Specify that +<var>lib</var> is the thread support library. This affects the Objective-C +compiler and runtime library, and exception handling for other languages +like C++. The possibilities for <var>lib</var> are: +</p> +<dl compact="compact"> +<dt><code>aix</code></dt> +<dd><p>AIX thread support. +</p></dd> +<dt><code>dce</code></dt> +<dd><p>DCE thread support. +</p></dd> +<dt><code>lynx</code></dt> +<dd><p>LynxOS thread support. +</p></dd> +<dt><code>mipssde</code></dt> +<dd><p>MIPS SDE thread support. +</p></dd> +<dt><code>no</code></dt> +<dd><p>This is an alias for ‘<samp>single</samp>’. +</p></dd> +<dt><code>posix</code></dt> +<dd><p>Generic POSIX/Unix98 thread support. +</p></dd> +<dt><code>rtems</code></dt> +<dd><p>RTEMS thread support. +</p></dd> +<dt><code>single</code></dt> +<dd><p>Disable thread support, should work for all platforms. +</p></dd> +<dt><code>tpf</code></dt> +<dd><p>TPF thread support. +</p></dd> +<dt><code>vxworks</code></dt> +<dd><p>VxWorks thread support. +</p></dd> +<dt><code>win32</code></dt> +<dd><p>Microsoft Win32 API thread support. +</p></dd> +</dl> + +</dd> +<dt><code>--enable-tls</code></dt> +<dd><p>Specify that the target supports TLS (Thread Local Storage). Usually +configure can correctly determine if TLS is supported. In cases where +it guesses incorrectly, TLS can be explicitly enabled or disabled with +<samp>--enable-tls</samp> or <samp>--disable-tls</samp>. This can happen if +the assembler supports TLS but the C library does not, or if the +assumptions made by the configure test are incorrect. +</p> +</dd> +<dt><code>--disable-tls</code></dt> +<dd><p>Specify that the target does not support TLS. +This is an alias for <samp>--enable-tls=no</samp>. +</p> +</dd> +<dt><code>--disable-tm-clone-registry</code></dt> +<dd><p>Disable TM clone registry in libgcc. It is enabled in libgcc by default. +This option helps to reduce code size for embedded targets which do +not use transactional memory. +</p> +</dd> +<dt><code>--with-cpu=<var>cpu</var></code></dt> +<dt><code>--with-cpu-32=<var>cpu</var></code></dt> +<dt><code>--with-cpu-64=<var>cpu</var></code></dt> +<dd><p>Specify which cpu variant the compiler should generate code for by default. +<var>cpu</var> will be used as the default value of the <samp>-mcpu=</samp> switch. +This option is only supported on some targets, including ARC, ARM, i386, M68k, +PowerPC, and SPARC. It is mandatory for ARC. The <samp>--with-cpu-32</samp> and +<samp>--with-cpu-64</samp> options specify separate default CPUs for +32-bit and 64-bit modes; these options are only supported for aarch64, i386, +x86-64, PowerPC, and SPARC. +</p> +</dd> +<dt><code>--with-schedule=<var>cpu</var></code></dt> +<dt><code>--with-arch=<var>cpu</var></code></dt> +<dt><code>--with-arch-32=<var>cpu</var></code></dt> +<dt><code>--with-arch-64=<var>cpu</var></code></dt> +<dt><code>--with-tune=<var>cpu</var></code></dt> +<dt><code>--with-tune-32=<var>cpu</var></code></dt> +<dt><code>--with-tune-64=<var>cpu</var></code></dt> +<dt><code>--with-abi=<var>abi</var></code></dt> +<dt><code>--with-fpu=<var>type</var></code></dt> +<dt><code>--with-float=<var>type</var></code></dt> +<dd><p>These configure options provide default values for the <samp>-mschedule=</samp>, +<samp>-march=</samp>, <samp>-mtune=</samp>, <samp>-mabi=</samp>, and <samp>-mfpu=</samp> +options and for <samp>-mhard-float</samp> or <samp>-msoft-float</samp>. As with +<samp>--with-cpu</samp>, which switches will be accepted and acceptable values +of the arguments depend on the target. +</p> +</dd> +<dt><code>--with-mode=<var>mode</var></code></dt> +<dd><p>Specify if the compiler should default to <samp>-marm</samp> or <samp>-mthumb</samp>. +This option is only supported on ARM targets. +</p> +</dd> +<dt><code>--with-stack-offset=<var>num</var></code></dt> +<dd><p>This option sets the default for the -mstack-offset=<var>num</var> option, +and will thus generally also control the setting of this option for +libraries. This option is only supported on Epiphany targets. +</p> +</dd> +<dt><code>--with-fpmath=<var>isa</var></code></dt> +<dd><p>This options sets <samp>-mfpmath=sse</samp> by default and specifies the default +ISA for floating-point arithmetics. You can select either ‘<samp>sse</samp>’ which +enables <samp>-msse2</samp> or ‘<samp>avx</samp>’ which enables <samp>-mavx</samp> by default. +This option is only supported on i386 and x86-64 targets. +</p> +</dd> +<dt><code>--with-fp-32=<var>mode</var></code></dt> +<dd><p>On MIPS targets, set the default value for the <samp>-mfp</samp> option when using +the o32 ABI. The possibilities for <var>mode</var> are: +</p><dl compact="compact"> +<dt><code>32</code></dt> +<dd><p>Use the o32 FP32 ABI extension, as with the <samp>-mfp32</samp> command-line +option. +</p></dd> +<dt><code>xx</code></dt> +<dd><p>Use the o32 FPXX ABI extension, as with the <samp>-mfpxx</samp> command-line +option. +</p></dd> +<dt><code>64</code></dt> +<dd><p>Use the o32 FP64 ABI extension, as with the <samp>-mfp64</samp> command-line +option. +</p></dd> +</dl> +<p>In the absence of this configuration option the default is to use the o32 +FP32 ABI extension. +</p> +</dd> +<dt><code>--with-odd-spreg-32</code></dt> +<dd><p>On MIPS targets, set the <samp>-modd-spreg</samp> option by default when using +the o32 ABI. +</p> +</dd> +<dt><code>--without-odd-spreg-32</code></dt> +<dd><p>On MIPS targets, set the <samp>-mno-odd-spreg</samp> option by default when using +the o32 ABI. This is normally used in conjunction with +<samp>--with-fp-32=64</samp> in order to target the o32 FP64A ABI extension. +</p> +</dd> +<dt><code>--with-nan=<var>encoding</var></code></dt> +<dd><p>On MIPS targets, set the default encoding convention to use for the +special not-a-number (NaN) IEEE 754 floating-point data. The +possibilities for <var>encoding</var> are: +</p><dl compact="compact"> +<dt><code>legacy</code></dt> +<dd><p>Use the legacy encoding, as with the <samp>-mnan=legacy</samp> command-line +option. +</p></dd> +<dt><code>2008</code></dt> +<dd><p>Use the 754-2008 encoding, as with the <samp>-mnan=2008</samp> command-line +option. +</p></dd> +</dl> +<p>To use this configuration option you must have an assembler version +installed that supports the <samp>-mnan=</samp> command-line option too. +In the absence of this configuration option the default convention is +the legacy encoding, as when neither of the <samp>-mnan=2008</samp> and +<samp>-mnan=legacy</samp> command-line options has been used. +</p> +</dd> +<dt><code>--with-divide=<var>type</var></code></dt> +<dd><p>Specify how the compiler should generate code for checking for +division by zero. This option is only supported on the MIPS target. +The possibilities for <var>type</var> are: +</p><dl compact="compact"> +<dt><code>traps</code></dt> +<dd><p>Division by zero checks use conditional traps (this is the default on +systems that support conditional traps). +</p></dd> +<dt><code>breaks</code></dt> +<dd><p>Division by zero checks use the break instruction. +</p></dd> +</dl> + +</dd> +<dt><code>--with-compact-branches=<var>policy</var></code></dt> +<dd><p>Specify how the compiler should generate branch instructions. +This option is only supported on the MIPS target. +The possibilities for <var>type</var> are: +</p><dl compact="compact"> +<dt><code>optimal</code></dt> +<dd><p>Cause a delay slot branch to be used if one is available in the +current ISA and the delay slot is successfully filled. If the delay slot +is not filled, a compact branch will be chosen if one is available. +</p></dd> +<dt><code>never</code></dt> +<dd><p>Ensures that compact branch instructions will never be generated. +</p></dd> +<dt><code>always</code></dt> +<dd><p>Ensures that a compact branch instruction will be generated if available. +If a compact branch instruction is not available, +a delay slot form of the branch will be used instead. +This option is supported from MIPS Release 6 onwards. +For pre-R6/microMIPS/MIPS16, this option is just same as never/optimal. +</p></dd> +</dl> + + +</dd> +<dt><code>--with-llsc</code></dt> +<dd><p>On MIPS targets, make <samp>-mllsc</samp> the default when no +<samp>-mno-llsc</samp> option is passed. This is the default for +Linux-based targets, as the kernel will emulate them if the ISA does +not provide them. +</p> +</dd> +<dt><code>--without-llsc</code></dt> +<dd><p>On MIPS targets, make <samp>-mno-llsc</samp> the default when no +<samp>-mllsc</samp> option is passed. +</p> +</dd> +<dt><code>--with-synci</code></dt> +<dd><p>On MIPS targets, make <samp>-msynci</samp> the default when no +<samp>-mno-synci</samp> option is passed. +</p> +</dd> +<dt><code>--without-synci</code></dt> +<dd><p>On MIPS targets, make <samp>-mno-synci</samp> the default when no +<samp>-msynci</samp> option is passed. This is the default. +</p> +</dd> +<dt><code>--with-lxc1-sxc1</code></dt> +<dd><p>On MIPS targets, make <samp>-mlxc1-sxc1</samp> the default when no +<samp>-mno-lxc1-sxc1</samp> option is passed. This is the default. +</p> +</dd> +<dt><code>--without-lxc1-sxc1</code></dt> +<dd><p>On MIPS targets, make <samp>-mno-lxc1-sxc1</samp> the default when no +<samp>-mlxc1-sxc1</samp> option is passed. The indexed load/store +instructions are not directly a problem but can lead to unexpected +behaviour when deployed in an application intended for a 32-bit address +space but run on a 64-bit processor. The issue is seen because all +known MIPS 64-bit Linux kernels execute o32 and n32 applications +with 64-bit addressing enabled which affects the overflow behaviour +of the indexed addressing mode. GCC will assume that ordinary +32-bit arithmetic overflow behaviour is the same whether performed +as an <code>addu</code> instruction or as part of the address calculation +in <code>lwxc1</code> type instructions. This assumption holds true in a +pure 32-bit environment and can hold true in a 64-bit environment if +the address space is accurately set to be 32-bit for o32 and n32. +</p> +</dd> +<dt><code>--with-madd4</code></dt> +<dd><p>On MIPS targets, make <samp>-mmadd4</samp> the default when no +<samp>-mno-madd4</samp> option is passed. This is the default. +</p> +</dd> +<dt><code>--without-madd4</code></dt> +<dd><p>On MIPS targets, make <samp>-mno-madd4</samp> the default when no +<samp>-mmadd4</samp> option is passed. The <code>madd4</code> instruction +family can be problematic when targeting a combination of cores that +implement these instructions differently. There are two known cores +that implement these as fused operations instead of unfused (where +unfused is normally expected). Disabling these instructions is the +only way to ensure compatible code is generated; this will incur +a performance penalty. +</p> +</dd> +<dt><code>--with-msa</code></dt> +<dd><p>On MIPS targets, make <samp>-mmsa</samp> the default when no +<samp>-mno-msa</samp> option is passed. +</p> +</dd> +<dt><code>--without-msa</code></dt> +<dd><p>On MIPS targets, make <samp>-mno-msa</samp> the default when no +<samp>-mmsa</samp> option is passed. This is the default. +</p> +</dd> +<dt><code>--with-mips-plt</code></dt> +<dd><p>On MIPS targets, make use of copy relocations and PLTs. +These features are extensions to the traditional +SVR4-based MIPS ABIs and require support from GNU binutils +and the runtime C library. +</p> +</dd> +<dt><code>--with-stack-clash-protection-guard-size=<var>size</var></code></dt> +<dd><p>On certain targets this option sets the default stack clash protection guard +size as a power of two in bytes. On AArch64 <var>size</var> is required to be either +12 (4KB) or 16 (64KB). +</p> +</dd> +<dt><code>--with-isa-spec=<var>ISA-spec-string</var></code></dt> +<dd><p>On RISC-V targets specify the default version of the RISC-V Unprivileged +(formerly User-Level) ISA specification to produce code conforming to. +The possibilities for <var>ISA-spec-string</var> are: +</p><dl compact="compact"> +<dt><code>2.2</code></dt> +<dd><p>Produce code conforming to version 2.2. +</p></dd> +<dt><code>20190608</code></dt> +<dd><p>Produce code conforming to version 20190608. +</p></dd> +<dt><code>20191213</code></dt> +<dd><p>Produce code conforming to version 20191213. +</p></dd> +</dl> +<p>In the absence of this configuration option the default version is 20191213. +</p> +</dd> +<dt><code>--enable-__cxa_atexit</code></dt> +<dd><p>Define if you want to use __cxa_atexit, rather than atexit, to +register C++ destructors for local statics and global objects. +This is essential for fully standards-compliant handling of +destructors, but requires __cxa_atexit in libc. This option is currently +only available on systems with GNU libc. When enabled, this will cause +<samp>-fuse-cxa-atexit</samp> to be passed by default. +</p> +</dd> +<dt><code>--enable-gnu-indirect-function</code></dt> +<dd><p>Define if you want to enable the <code>ifunc</code> attribute. This option is +currently only available on systems with GNU libc on certain targets. +</p> +</dd> +<dt><code>--enable-target-optspace</code></dt> +<dd><p>Specify that target +libraries should be optimized for code space instead of code speed. +This is the default for the m32r platform. +</p> +</dd> +<dt><code>--with-cpp-install-dir=<var>dirname</var></code></dt> +<dd><p>Specify that the user visible <code>cpp</code> program should be installed +in <samp><var>prefix</var>/<var>dirname</var>/cpp</samp>, in addition to <var>bindir</var>. +</p> +</dd> +<dt><code>--enable-comdat</code></dt> +<dd><p>Enable COMDAT group support. This is primarily used to override the +automatically detected value. +</p> +</dd> +<dt><code>--enable-initfini-array</code></dt> +<dd><p>Force the use of sections <code>.init_array</code> and <code>.fini_array</code> +(instead of <code>.init</code> and <code>.fini</code>) for constructors and +destructors. Option <samp>--disable-initfini-array</samp> has the +opposite effect. If neither option is specified, the configure script +will try to guess whether the <code>.init_array</code> and +<code>.fini_array</code> sections are supported and, if they are, use them. +</p> +</dd> +<dt><code>--enable-link-mutex</code></dt> +<dd><p>When building GCC, use a mutex to avoid linking the compilers for +multiple languages at the same time, to avoid thrashing on build +systems with limited free memory. The default is not to use such a mutex. +</p> +</dd> +<dt><code>--enable-link-serialization</code></dt> +<dd><p>When building GCC, use make dependencies to serialize linking the compilers for +multiple languages, to avoid thrashing on build +systems with limited free memory. The default is not to add such +dependencies and thus with parallel make potentially link different +compilers concurrently. If the argument is a positive integer, allow +that number of concurrent link processes for the large binaries. +</p> +</dd> +<dt><code>--enable-maintainer-mode</code></dt> +<dd><p>The build rules that regenerate the Autoconf and Automake output files as +well as the GCC master message catalog <samp>gcc.pot</samp> are normally +disabled. This is because it can only be rebuilt if the complete source +tree is present. If you have changed the sources and want to rebuild the +catalog, configuring with <samp>--enable-maintainer-mode</samp> will enable +this. Note that you need a recent version of the <code>gettext</code> tools +to do so. +</p> +</dd> +<dt><code>--disable-bootstrap</code></dt> +<dd><p>For a native build, the default configuration is to perform +a 3-stage bootstrap of the compiler when ‘<samp>make</samp>’ is invoked, +testing that GCC can compile itself correctly. If you want to disable +this process, you can configure with <samp>--disable-bootstrap</samp>. +</p> +</dd> +<dt><code>--enable-bootstrap</code></dt> +<dd><p>In special cases, you may want to perform a 3-stage build +even if the target and host triplets are different. +This is possible when the host can run code compiled for +the target (e.g. host is i686-linux, target is i486-linux). +Starting from GCC 4.2, to do this you have to configure explicitly +with <samp>--enable-bootstrap</samp>. +</p> +</dd> +<dt><code>--enable-generated-files-in-srcdir</code></dt> +<dd><p>Neither the .c and .h files that are generated from Bison and flex nor the +info manuals and man pages that are built from the .texi files are present +in the repository development tree. When building GCC from that development tree, +or from one of our snapshots, those generated files are placed in your +build directory, which allows for the source to be in a readonly +directory. +</p> +<p>If you configure with <samp>--enable-generated-files-in-srcdir</samp> then those +generated files will go into the source directory. This is mainly intended +for generating release or prerelease tarballs of the GCC sources, since it +is not a requirement that the users of source releases to have flex, Bison, +or makeinfo. +</p> +</dd> +<dt><code>--enable-version-specific-runtime-libs</code></dt> +<dd><p>Specify +that runtime libraries should be installed in the compiler specific +subdirectory (<samp><var>libdir</var>/gcc</samp>) rather than the usual places. In +addition, ‘<samp>libstdc++</samp>’’s include files will be installed into +<samp><var>libdir</var></samp> unless you overruled it by using +<samp>--with-gxx-include-dir=<var>dirname</var></samp>. Using this option is +particularly useful if you intend to use several versions of GCC in +parallel. The default is ‘<samp>yes</samp>’ for ‘<samp>libada</samp>’, and ‘<samp>no</samp>’ for +the remaining libraries. +</p> +</dd> +<dt><code><a name="WithAixSoname"></a>--with-aix-soname=‘<samp>aix</samp>’, ‘<samp>svr4</samp>’ or ‘<samp>both</samp>’</code></dt> +<dd><p>Traditional AIX shared library versioning (versioned <code>Shared Object</code> +files as members of unversioned <code>Archive Library</code> files named +‘<samp>lib.a</samp>’) causes numerous headaches for package managers. However, +<code>Import Files</code> as members of <code>Archive Library</code> files allow for +<strong>filename-based versioning</strong> of shared libraries as seen on Linux/SVR4, +where this is called the "SONAME". But as they prevent static linking, +<code>Import Files</code> may be used with <code>Runtime Linking</code> only, where the +linker does search for ‘<samp>libNAME.so</samp>’ before ‘<samp>libNAME.a</samp>’ library +filenames with the ‘<samp>-lNAME</samp>’ linker flag. +</p> +<a name="AixLdCommand"></a><p>For detailed information please refer to the AIX +<a href="https://www.ibm.com/support/knowledgecenter/search/%22the%20ld%20command%2C%20also%20called%20the%20linkage%20editor%20or%20binder%22">ld +Command</a> reference. +</p> +<p>As long as shared library creation is enabled, upon: +</p><dl compact="compact"> +<dt><code>--with-aix-soname=aix</code></dt> +<dt><code>--with-aix-soname=both</code></dt> +<dd><p>A (traditional AIX) <code>Shared Archive Library</code> file is created: + </p><ul> +<li> using the ‘<samp>libNAME.a</samp>’ filename scheme + </li><li> with the <code>Shared Object</code> file as archive member named + ‘<samp>libNAME.so.V</samp>’ (except for ‘<samp>libgcc_s</samp>’, where the <code>Shared + Object</code> file is named ‘<samp>shr.o</samp>’ for backwards compatibility), which + <ul class="no-bullet"> +<li>- is used for runtime loading from inside the ‘<samp>libNAME.a</samp>’ file + </li><li>- is used for dynamic loading via + <code>dlopen("libNAME.a(libNAME.so.V)", RTLD_MEMBER)</code> + </li><li>- is used for shared linking + </li><li>- is used for static linking, so no separate <code>Static Archive + Library</code> file is needed + </li></ul> +</li></ul> +</dd> +<dt><code>--with-aix-soname=both</code></dt> +<dt><code>--with-aix-soname=svr4</code></dt> +<dd><p>A (second) <code>Shared Archive Library</code> file is created: + </p><ul> +<li> using the ‘<samp>libNAME.so.V</samp>’ filename scheme + </li><li> with the <code>Shared Object</code> file as archive member named + ‘<samp>shr.o</samp>’, which + <ul class="no-bullet"> +<li>- is created with the <code>-G linker flag</code> + </li><li>- has the <code>F_LOADONLY</code> flag set + </li><li>- is used for runtime loading from inside the ‘<samp>libNAME.so.V</samp>’ file + </li><li>- is used for dynamic loading via <code>dlopen("libNAME.so.V(shr.o)", + RTLD_MEMBER)</code> + </li></ul> +</li><li> with the <code>Import File</code> as archive member named ‘<samp>shr.imp</samp>’, + which + <ul class="no-bullet"> +<li>- refers to ‘<samp>libNAME.so.V(shr.o)</samp>’ as the "SONAME", to be recorded + in the <code>Loader Section</code> of subsequent binaries + </li><li>- indicates whether ‘<samp>libNAME.so.V(shr.o)</samp>’ is 32 or 64 bit + </li><li>- lists all the public symbols exported by ‘<samp>lib.so.V(shr.o)</samp>’, + eventually decorated with the <code>‘<samp>weak</samp>’ Keyword</code> + </li><li>- is necessary for shared linking against ‘<samp>lib.so.V(shr.o)</samp>’ + </li></ul> +</li></ul> +<p>A symbolic link using the ‘<samp>libNAME.so</samp>’ filename scheme is created: + </p><ul> +<li> pointing to the ‘<samp>libNAME.so.V</samp>’ <code>Shared Archive Library</code> file + </li><li> to permit the <code>ld Command</code> to find ‘<samp>lib.so.V(shr.imp)</samp>’ via + the ‘<samp>-lNAME</samp>’ argument (requires <code>Runtime Linking</code> to be enabled) + </li><li> to permit dynamic loading of ‘<samp>lib.so.V(shr.o)</samp>’ without the need + to specify the version number via <code>dlopen("libNAME.so(shr.o)", + RTLD_MEMBER)</code> + </li></ul> +</dd> +</dl> + +<p>As long as static library creation is enabled, upon: +</p><dl compact="compact"> +<dt><code>--with-aix-soname=svr4</code></dt> +<dd><p>A <code>Static Archive Library</code> is created: + </p><ul> +<li> using the ‘<samp>libNAME.a</samp>’ filename scheme + </li><li> with all the <code>Static Object</code> files as archive members, which + <ul class="no-bullet"> +<li>- are used for static linking + </li></ul> +</li></ul> +</dd> +</dl> + +<p>While the aix-soname=‘<samp>svr4</samp>’ option does not create <code>Shared Object</code> +files as members of unversioned <code>Archive Library</code> files any more, package +managers still are responsible to +<a href="./specific.html#TransferAixShobj">transfer</a> <code>Shared Object</code> files +found as member of a previously installed unversioned <code>Archive Library</code> +file into the newly installed <code>Archive Library</code> file with the same +filename. +</p> +<p><em>WARNING:</em> Creating <code>Shared Object</code> files with <code>Runtime Linking</code> +enabled may bloat the TOC, eventually leading to <code>TOC overflow</code> errors, +requiring the use of either the <samp>-Wl,-bbigtoc</samp> linker flag (seen to +break with the <code>GDB</code> debugger) or some of the TOC-related compiler flags, +see “RS/6000 and PowerPC Options” in the main manual. +</p> +<p><samp>--with-aix-soname</samp> is currently supported by ‘<samp>libgcc_s</samp>’ only, so +this option is still experimental and not for normal use yet. +</p> +<p>Default is the traditional behavior <samp>--with-aix-soname=‘<samp>aix</samp>’</samp>. +</p> +</dd> +<dt><code>--enable-languages=<var>lang1</var>,<var>lang2</var>,…</code></dt> +<dd><p>Specify that only a particular subset of compilers and +their runtime libraries should be built. For a list of valid values for +<var>langN</var> you can issue the following command in the +<samp>gcc</samp> directory of your GCC source tree:<br> +</p><div class="smallexample"> +<pre class="smallexample">grep ^language= */config-lang.in +</pre></div> +<p>Currently, you can use any of the following: +<code>all</code>, <code>default</code>, <code>ada</code>, <code>c</code>, <code>c++</code>, <code>d</code>, +<code>fortran</code>, <code>go</code>, <code>jit</code>, <code>lto</code>, <code>m2</code>, +<code>objc</code>, <code>obj-c++</code>. +Building the Ada compiler has special requirements, see below. +If you do not pass this flag, or specify the option <code>default</code>, then the +default languages available in the <samp>gcc</samp> sub-tree will be configured. +Ada, D, Go, Jit, Objective-C++ and Modula-2 are not default languages. +LTO is not a +default language, but is built by default because <samp>--enable-lto</samp> is +enabled by default. The other languages are default languages. If +<code>all</code> is specified, then all available languages are built. An +exception is <code>jit</code> language, which requires +<samp>--enable-host-shared</samp> to be included with <code>all</code>. +</p> +</dd> +<dt><code>--enable-stage1-languages=<var>lang1</var>,<var>lang2</var>,…</code></dt> +<dd><p>Specify that a particular subset of compilers and their runtime +libraries should be built with the system C compiler during stage 1 of +the bootstrap process, rather than only in later stages with the +bootstrapped C compiler. The list of valid values is the same as for +<samp>--enable-languages</samp>, and the option <code>all</code> will select all +of the languages enabled by <samp>--enable-languages</samp>. This option is +primarily useful for GCC development; for instance, when a development +version of the compiler cannot bootstrap due to compiler bugs, or when +one is debugging front ends other than the C front end. When this +option is used, one can then build the target libraries for the +specified languages with the stage-1 compiler by using <code>make +stage1-bubble all-target</code>, or run the testsuite on the stage-1 compiler +for the specified languages using <code>make stage1-start check-gcc</code>. +</p> +</dd> +<dt><code>--disable-libada</code></dt> +<dd><p>Specify that the run-time libraries and tools used by GNAT should not +be built. This can be useful for debugging, or for compatibility with +previous Ada build procedures, when it was required to explicitly +do a ‘<samp>make -C gcc gnatlib_and_tools</samp>’. +</p> +</dd> +<dt><code>--disable-libgm2</code></dt> +<dd><p>Specify that the run-time libraries and tools used by Modula-2 should not +be built. This can be useful for debugging. +</p> +</dd> +<dt><code>--disable-libsanitizer</code></dt> +<dd><p>Specify that the run-time libraries for the various sanitizers should +not be built. +</p> +</dd> +<dt><code>--disable-libssp</code></dt> +<dd><p>Specify that the run-time libraries for stack smashing protection +should not be built or linked against. On many targets library support +is provided by the C library instead. +</p> +</dd> +<dt><code>--disable-libquadmath</code></dt> +<dd><p>Specify that the GCC quad-precision math library should not be built. +On some systems, the library is required to be linkable when building +the Fortran front end, unless <samp>--disable-libquadmath-support</samp> +is used. +</p> +</dd> +<dt><code>--disable-libquadmath-support</code></dt> +<dd><p>Specify that the Fortran front end and <code>libgfortran</code> do not add +support for <code>libquadmath</code> on systems supporting it. +</p> +</dd> +<dt><code>--disable-libgomp</code></dt> +<dd><p>Specify that the GNU Offloading and Multi Processing Runtime Library +should not be built. +</p> +</dd> +<dt><code>--disable-libvtv</code></dt> +<dd><p>Specify that the run-time libraries used by vtable verification +should not be built. +</p> +</dd> +<dt><code>--with-dwarf2</code></dt> +<dd><p>Specify that the compiler should +use DWARF debugging information as the default; the exact +DWARF version that is the default is target-specific. +</p> +</dd> +<dt><code>--with-advance-toolchain=<var>at</var></code></dt> +<dd><p>On 64-bit PowerPC Linux systems, configure the compiler to use the +header files, library files, and the dynamic linker from the Advance +Toolchain release <var>at</var> instead of the default versions that are +provided by the Linux distribution. In general, this option is +intended for the developers of GCC, and it is not intended for general +use. +</p> +</dd> +<dt><code>--enable-targets=all</code></dt> +<dt><code>--enable-targets=<var>target_list</var></code></dt> +<dd><p>Some GCC targets, e.g. powerpc64-linux, build bi-arch compilers. +These are compilers that are able to generate either 64-bit or 32-bit +code. Typically, the corresponding 32-bit target, e.g. +powerpc-linux for powerpc64-linux, only generates 32-bit code. This +option enables the 32-bit target to be a bi-arch compiler, which is +useful when you want a bi-arch compiler that defaults to 32-bit, and +you are building a bi-arch or multi-arch binutils in a combined tree. +On mips-linux, this will build a tri-arch compiler (ABI o32/n32/64), +defaulted to o32. +Currently, this option only affects sparc-linux, powerpc-linux, x86-linux, +mips-linux and s390-linux. +</p> +</dd> +<dt><code>--enable-default-pie</code></dt> +<dd><p>Turn on <samp>-fPIE</samp> and <samp>-pie</samp> by default. +</p> +</dd> +<dt><code>--enable-secureplt</code></dt> +<dd><p>This option enables <samp>-msecure-plt</samp> by default for powerpc-linux. +See “RS/6000 and PowerPC Options” in the main manual +</p> +</dd> +<dt><code>--enable-default-ssp</code></dt> +<dd><p>Turn on <samp>-fstack-protector-strong</samp> by default. +</p> +</dd> +<dt><code>--enable-cld</code></dt> +<dd><p>This option enables <samp>-mcld</samp> by default for 32-bit x86 targets. +See “i386 and x86-64 Options” in the main manual +</p> +</dd> +<dt><code>--enable-large-address-aware</code></dt> +<dd><p>The <samp>--enable-large-address-aware</samp> option arranges for MinGW +executables to be linked using the <samp>--large-address-aware</samp> +option, that enables the use of more than 2GB of memory. If GCC is +configured with this option, its effects can be reversed by passing the +<samp>-Wl,--disable-large-address-aware</samp> option to the so-configured +compiler driver. +</p> +</dd> +<dt><code>--enable-win32-registry</code></dt> +<dt><code>--enable-win32-registry=<var>key</var></code></dt> +<dt><code>--disable-win32-registry</code></dt> +<dd><p>The <samp>--enable-win32-registry</samp> option enables Microsoft Windows-hosted GCC +to look up installations paths in the registry using the following key: +</p> +<div class="smallexample"> +<pre class="smallexample"><code>HKEY_LOCAL_MACHINE\SOFTWARE\Free Software Foundation\<var>key</var></code> +</pre></div> + +<p><var>key</var> defaults to GCC version number, and can be overridden by the +<samp>--enable-win32-registry=<var>key</var></samp> option. Vendors and distributors +who use custom installers are encouraged to provide a different key, +perhaps one comprised of vendor name and GCC version number, to +avoid conflict with existing installations. This feature is enabled +by default, and can be disabled by <samp>--disable-win32-registry</samp> +option. This option has no effect on the other hosts. +</p> +</dd> +<dt><code>--nfp</code></dt> +<dd><p>Specify that the machine does not have a floating point unit. This +option only applies to ‘<samp>m68k-sun-sunos<var>n</var></samp>’. On any other +system, <samp>--nfp</samp> has no effect. +</p> +</dd> +<dt><code>--enable-werror</code></dt> +<dt><code>--disable-werror</code></dt> +<dt><code>--enable-werror=yes</code></dt> +<dt><code>--enable-werror=no</code></dt> +<dd><p>When you specify this option, it controls whether certain files in the +compiler are built with <samp>-Werror</samp> in bootstrap stage2 and later. +If you don’t specify it, <samp>-Werror</samp> is turned on for the main +development trunk. However it defaults to off for release branches and +final releases. The specific files which get <samp>-Werror</samp> are +controlled by the Makefiles. +</p> +</dd> +<dt><code>--enable-checking</code></dt> +<dt><code>--disable-checking</code></dt> +<dt><code>--enable-checking=<var>list</var></code></dt> +<dd><p>This option controls performing internal consistency checks in the compiler. +It does not change the generated code, but adds error checking of the +requested complexity. This slows down the compiler and may only work +properly if you are building the compiler with GCC. +</p> +<p>When the option is not specified, the active set of checks depends on context. +Namely, bootstrap stage 1 defaults to ‘<samp>--enable-checking=yes</samp>’, builds +from release branches or release archives default to +‘<samp>--enable-checking=release</samp>’, and otherwise +‘<samp>--enable-checking=yes,extra</samp>’ is used. When the option is +specified without a <var>list</var>, the result is the same as +‘<samp>--enable-checking=yes</samp>’. Likewise, ‘<samp>--disable-checking</samp>’ is +equivalent to ‘<samp>--enable-checking=no</samp>’. +</p> +<p>The categories of checks available in <var>list</var> are ‘<samp>yes</samp>’ (most common +checks ‘<samp>assert,misc,gc,gimple,rtlflag,runtime,tree,types</samp>’), ‘<samp>no</samp>’ +(no checks at all), ‘<samp>all</samp>’ (all but ‘<samp>valgrind</samp>’), ‘<samp>release</samp>’ +(cheapest checks ‘<samp>assert,runtime</samp>’) or ‘<samp>none</samp>’ (same as ‘<samp>no</samp>’). +‘<samp>release</samp>’ checks are always on and to disable them +‘<samp>--disable-checking</samp>’ or ‘<samp>--enable-checking=no[,<other checks>]</samp>’ +must be explicitly requested. Disabling assertions makes the compiler and +runtime slightly faster but increases the risk of undetected internal errors +causing wrong code to be generated. +</p> +<p>Individual checks can be enabled with these flags: ‘<samp>assert</samp>’, ‘<samp>df</samp>’, +‘<samp>extra</samp>’, ‘<samp>fold</samp>’, ‘<samp>gc</samp>’, ‘<samp>gcac</samp>’, ‘<samp>gimple</samp>’, +‘<samp>misc</samp>’, ‘<samp>rtl</samp>’, ‘<samp>rtlflag</samp>’, ‘<samp>runtime</samp>’, ‘<samp>tree</samp>’, +‘<samp>types</samp>’ and ‘<samp>valgrind</samp>’. ‘<samp>extra</samp>’ extends ‘<samp>misc</samp>’ +checking with extra checks that might affect code generation and should +therefore not differ between stage1 and later stages in bootstrap. +</p> +<p>The ‘<samp>valgrind</samp>’ check requires the external <code>valgrind</code> simulator, +available from <a href="https://valgrind.org">https://valgrind.org</a>. The ‘<samp>rtl</samp>’ checks are +expensive and the ‘<samp>df</samp>’, ‘<samp>gcac</samp>’ and ‘<samp>valgrind</samp>’ checks are very +expensive. +</p> +</dd> +<dt><code>--disable-stage1-checking</code></dt> +<dt><code>--enable-stage1-checking</code></dt> +<dt><code>--enable-stage1-checking=<var>list</var></code></dt> +<dd><p>This option affects only bootstrap build. If no <samp>--enable-checking</samp> +option is specified the stage1 compiler is built with ‘<samp>yes</samp>’ checking +enabled, otherwise the stage1 checking flags are the same as specified by +<samp>--enable-checking</samp>. To build the stage1 compiler with +different checking options use <samp>--enable-stage1-checking</samp>. +The list of checking options is the same as for <samp>--enable-checking</samp>. +If your system is too slow or too small to bootstrap a released compiler +with checking for stage1 enabled, you can use ‘<samp>--disable-stage1-checking</samp>’ +to disable checking for the stage1 compiler. +</p> +</dd> +<dt><code>--enable-coverage</code></dt> +<dt><code>--enable-coverage=<var>level</var></code></dt> +<dd><p>With this option, the compiler is built to collect self coverage +information, every time it is run. This is for internal development +purposes, and only works when the compiler is being built with gcc. The +<var>level</var> argument controls whether the compiler is built optimized or +not, values are ‘<samp>opt</samp>’ and ‘<samp>noopt</samp>’. For coverage analysis you +want to disable optimization, for performance analysis you want to +enable optimization. When coverage is enabled, the default level is +without optimization. +</p> +</dd> +<dt><code>--enable-gather-detailed-mem-stats</code></dt> +<dd><p>When this option is specified more detailed information on memory +allocation is gathered. This information is printed when using +<samp>-fmem-report</samp>. +</p> +</dd> +<dt><code>--enable-valgrind-annotations</code></dt> +<dd><p>Mark selected memory related operations in the compiler when run under +valgrind to suppress false positives. +</p> +</dd> +<dt><code>--enable-nls</code></dt> +<dt><code>--disable-nls</code></dt> +<dd><p>The <samp>--enable-nls</samp> option enables Native Language Support (NLS), +which lets GCC output diagnostics in languages other than American +English. Native Language Support is enabled by default if not doing a +canadian cross build. The <samp>--disable-nls</samp> option disables NLS. +</p> +</dd> +<dt><code>--with-included-gettext</code></dt> +<dd><p>If NLS is enabled, the <samp>--with-included-gettext</samp> option causes the build +procedure to prefer its copy of GNU <code>gettext</code>. +</p> +</dd> +<dt><code>--with-catgets</code></dt> +<dd><p>If NLS is enabled, and if the host lacks <code>gettext</code> but has the +inferior <code>catgets</code> interface, the GCC build procedure normally +ignores <code>catgets</code> and instead uses GCC’s copy of the GNU +<code>gettext</code> library. The <samp>--with-catgets</samp> option causes the +build procedure to use the host’s <code>catgets</code> in this situation. +</p> +</dd> +<dt><code>--with-libiconv-prefix=<var>dir</var></code></dt> +<dd><p>Search for libiconv header files in <samp><var>dir</var>/include</samp> and +libiconv library files in <samp><var>dir</var>/lib</samp>. +</p> +</dd> +<dt><code>--enable-obsolete</code></dt> +<dd><p>Enable configuration for an obsoleted system. If you attempt to +configure GCC for a system (build, host, or target) which has been +obsoleted, and you do not specify this flag, configure will halt with an +error message. +</p> +<p>All support for systems which have been obsoleted in one release of GCC +is removed entirely in the next major release, unless someone steps +forward to maintain the port. +</p> +</dd> +<dt><code>--enable-decimal-float</code></dt> +<dt><code>--enable-decimal-float=yes</code></dt> +<dt><code>--enable-decimal-float=no</code></dt> +<dt><code>--enable-decimal-float=bid</code></dt> +<dt><code>--enable-decimal-float=dpd</code></dt> +<dt><code>--disable-decimal-float</code></dt> +<dd><p>Enable (or disable) support for the C decimal floating point extension +that is in the IEEE 754-2008 standard. This is enabled by default +only on AArch64, PowerPC, i386, and x86_64 GNU/Linux systems. Other +systems may also support it, but require the user to specifically +enable it. You can optionally control which decimal floating point +format is used (either ‘<samp>bid</samp>’ or ‘<samp>dpd</samp>’). The ‘<samp>bid</samp>’ +(binary integer decimal) format is default on AArch64, i386 and x86_64 +systems, and the ‘<samp>dpd</samp>’ (densely packed decimal) format is default +on PowerPC systems. +</p> +</dd> +<dt><code>--enable-fixed-point</code></dt> +<dt><code>--disable-fixed-point</code></dt> +<dd><p>Enable (or disable) support for C fixed-point arithmetic. +This option is enabled by default for some targets (such as MIPS) which +have hardware-support for fixed-point operations. On other targets, you +may enable this option manually. +</p> +</dd> +<dt><code>--with-long-double-128</code></dt> +<dd><p>Specify if <code>long double</code> type should be 128-bit by default on selected +GNU/Linux architectures. If using <code>--without-long-double-128</code>, +<code>long double</code> will be by default 64-bit, the same as <code>double</code> type. +When neither of these configure options are used, the default will be +128-bit <code>long double</code> when built against GNU C Library 2.4 and later, +64-bit <code>long double</code> otherwise. +</p> +</dd> +<dt><code>--with-long-double-format=ibm</code></dt> +<dt><code>--with-long-double-format=ieee</code></dt> +<dd><p>Specify whether <code>long double</code> uses the IBM extended double format +or the IEEE 128-bit floating point format on PowerPC Linux systems. +This configuration switch will only work on little endian PowerPC +Linux systems and on big endian 64-bit systems where the default cpu +is at least power7 (i.e. <samp>--with-cpu=power7</samp>, +<samp>--with-cpu=power8</samp>, or <samp>--with-cpu=power9</samp> is used). +</p> +<p>If you use the <samp>--with-long-double-64</samp> configuration option, +the <samp>--with-long-double-format=ibm</samp> and +<samp>--with-long-double-format=ieee</samp> options are ignored. +</p> +<p>The default <code>long double</code> format is to use IBM extended double. +Until all of the libraries are converted to use IEEE 128-bit floating +point, it is not recommended to use +<samp>--with-long-double-format=ieee</samp>. +</p> +</dd> +<dt><code>--enable-fdpic</code></dt> +<dd><p>On SH Linux systems, generate ELF FDPIC code. +</p> +</dd> +<dt><code>--with-gmp=<var>pathname</var></code></dt> +<dt><code>--with-gmp-include=<var>pathname</var></code></dt> +<dt><code>--with-gmp-lib=<var>pathname</var></code></dt> +<dt><code>--with-mpfr=<var>pathname</var></code></dt> +<dt><code>--with-mpfr-include=<var>pathname</var></code></dt> +<dt><code>--with-mpfr-lib=<var>pathname</var></code></dt> +<dt><code>--with-mpc=<var>pathname</var></code></dt> +<dt><code>--with-mpc-include=<var>pathname</var></code></dt> +<dt><code>--with-mpc-lib=<var>pathname</var></code></dt> +<dd><p>If you want to build GCC but do not have the GMP library, the MPFR +library and/or the MPC library installed in a standard location and +do not have their sources present in the GCC source tree then you +can explicitly specify the directory where they are installed +(‘<samp>--with-gmp=<var>gmpinstalldir</var></samp>’, +‘<samp>--with-mpfr=<var>mpfrinstalldir</var></samp>’, +‘<samp>--with-mpc=<var>mpcinstalldir</var></samp>’). The +<samp>--with-gmp=<var>gmpinstalldir</var></samp> option is shorthand for +<samp>--with-gmp-lib=<var>gmpinstalldir</var>/lib</samp> and +<samp>--with-gmp-include=<var>gmpinstalldir</var>/include</samp>. Likewise the +<samp>--with-mpfr=<var>mpfrinstalldir</var></samp> option is shorthand for +<samp>--with-mpfr-lib=<var>mpfrinstalldir</var>/lib</samp> and +<samp>--with-mpfr-include=<var>mpfrinstalldir</var>/include</samp>, also the +<samp>--with-mpc=<var>mpcinstalldir</var></samp> option is shorthand for +<samp>--with-mpc-lib=<var>mpcinstalldir</var>/lib</samp> and +<samp>--with-mpc-include=<var>mpcinstalldir</var>/include</samp>. If these +shorthand assumptions are not correct, you can use the explicit +include and lib options directly. You might also need to ensure the +shared libraries can be found by the dynamic linker when building and +using GCC, for example by setting the runtime shared library path +variable (<code>LD_LIBRARY_PATH</code> on GNU/Linux and Solaris systems). +</p> +<p>These flags are applicable to the host platform only. When building +a cross compiler, they will not be used to configure target libraries. +</p> +</dd> +<dt><code>--with-isl=<var>pathname</var></code></dt> +<dt><code>--with-isl-include=<var>pathname</var></code></dt> +<dt><code>--with-isl-lib=<var>pathname</var></code></dt> +<dd><p>If you do not have the isl library installed in a standard location and you +want to build GCC, you can explicitly specify the directory where it is +installed (‘<samp>--with-isl=<var>islinstalldir</var></samp>’). The +<samp>--with-isl=<var>islinstalldir</var></samp> option is shorthand for +<samp>--with-isl-lib=<var>islinstalldir</var>/lib</samp> and +<samp>--with-isl-include=<var>islinstalldir</var>/include</samp>. If this +shorthand assumption is not correct, you can use the explicit +include and lib options directly. +</p> +<p>These flags are applicable to the host platform only. When building +a cross compiler, they will not be used to configure target libraries. +</p> +</dd> +<dt><code>--with-stage1-ldflags=<var>flags</var></code></dt> +<dd><p>This option may be used to set linker flags to be used when linking +stage 1 of GCC. These are also used when linking GCC if configured with +<samp>--disable-bootstrap</samp>. If <samp>--with-stage1-libs</samp> is not set to a +value, then the default is ‘<samp>-static-libstdc++ -static-libgcc</samp>’, if +supported. +</p> +</dd> +<dt><code>--with-stage1-libs=<var>libs</var></code></dt> +<dd><p>This option may be used to set libraries to be used when linking stage 1 +of GCC. These are also used when linking GCC if configured with +<samp>--disable-bootstrap</samp>. +</p> +</dd> +<dt><code>--with-boot-ldflags=<var>flags</var></code></dt> +<dd><p>This option may be used to set linker flags to be used when linking +stage 2 and later when bootstrapping GCC. If –with-boot-libs +is not is set to a value, then the default is +‘<samp>-static-libstdc++ -static-libgcc</samp>’. +</p> +</dd> +<dt><code>--with-boot-libs=<var>libs</var></code></dt> +<dd><p>This option may be used to set libraries to be used when linking stage 2 +and later when bootstrapping GCC. +</p> +</dd> +<dt><code>--with-debug-prefix-map=<var>map</var></code></dt> +<dd><p>Convert source directory names using <samp>-fdebug-prefix-map</samp> when +building runtime libraries. ‘<samp><var>map</var></samp>’ is a space-separated +list of maps of the form ‘<samp><var>old</var>=<var>new</var></samp>’. +</p> +</dd> +<dt><code>--enable-linker-build-id</code></dt> +<dd><p>Tells GCC to pass <samp>--build-id</samp> option to the linker for all final +links (links performed without the <samp>-r</samp> or <samp>--relocatable</samp> +option), if the linker supports it. If you specify +<samp>--enable-linker-build-id</samp>, but your linker does not +support <samp>--build-id</samp> option, a warning is issued and the +<samp>--enable-linker-build-id</samp> option is ignored. The default is off. +</p> +</dd> +<dt><code>--with-linker-hash-style=<var>choice</var></code></dt> +<dd><p>Tells GCC to pass <samp>--hash-style=<var>choice</var></samp> option to the +linker for all final links. <var>choice</var> can be one of +‘<samp>sysv</samp>’, ‘<samp>gnu</samp>’, and ‘<samp>both</samp>’ where ‘<samp>sysv</samp>’ is the default. +</p> +</dd> +<dt><code>--enable-gnu-unique-object</code></dt> +<dt><code>--disable-gnu-unique-object</code></dt> +<dd><p>Tells GCC to use the gnu_unique_object relocation for C++ template +static data members and inline function local statics. Enabled by +default for a toolchain with an assembler that accepts it and +GLIBC 2.11 or above, otherwise disabled. +</p> +</dd> +<dt><code>--with-diagnostics-color=<var>choice</var></code></dt> +<dd><p>Tells GCC to use <var>choice</var> as the default for <samp>-fdiagnostics-color=</samp> +option (if not used explicitly on the command line). <var>choice</var> +can be one of ‘<samp>never</samp>’, ‘<samp>auto</samp>’, ‘<samp>always</samp>’, and ‘<samp>auto-if-env</samp>’ +where ‘<samp>auto</samp>’ is the default. ‘<samp>auto-if-env</samp>’ makes +<samp>-fdiagnostics-color=auto</samp> the default if <code>GCC_COLORS</code> +is present and non-empty in the environment of the compiler, and +<samp>-fdiagnostics-color=never</samp> otherwise. +</p> +</dd> +<dt><code>--with-diagnostics-urls=<var>choice</var></code></dt> +<dd><p>Tells GCC to use <var>choice</var> as the default for <samp>-fdiagnostics-urls=</samp> +option (if not used explicitly on the command line). <var>choice</var> +can be one of ‘<samp>never</samp>’, ‘<samp>auto</samp>’, ‘<samp>always</samp>’, and ‘<samp>auto-if-env</samp>’ +where ‘<samp>auto</samp>’ is the default. ‘<samp>auto-if-env</samp>’ makes +<samp>-fdiagnostics-urls=auto</samp> the default if <code>GCC_URLS</code> +or <code>TERM_URLS</code> is present and non-empty in the environment of the +compiler, and <samp>-fdiagnostics-urls=never</samp> otherwise. +</p> +</dd> +<dt><code>--enable-lto</code></dt> +<dt><code>--disable-lto</code></dt> +<dd><p>Enable support for link-time optimization (LTO). This is enabled by +default, and may be disabled using <samp>--disable-lto</samp>. +</p> +</dd> +<dt><code>--enable-linker-plugin-configure-flags=FLAGS</code></dt> +<dt><code>--enable-linker-plugin-flags=FLAGS</code></dt> +<dd><p>By default, linker plugins (such as the LTO plugin) are built for the +host system architecture. For the case that the linker has a +different (but run-time compatible) architecture, these flags can be +specified to build plugins that are compatible to the linker. For +example, if you are building GCC for a 64-bit x86_64 +(‘<samp>x86_64-pc-linux-gnu</samp>’) host system, but have a 32-bit x86 +GNU/Linux (‘<samp>i686-pc-linux-gnu</samp>’) linker executable (which is +executable on the former system), you can configure GCC as follows for +getting compatible linker plugins: +</p> +<div class="smallexample"> +<pre class="smallexample">% <var>srcdir</var>/configure \ + --host=x86_64-pc-linux-gnu \ + --enable-linker-plugin-configure-flags=--host=i686-pc-linux-gnu \ + --enable-linker-plugin-flags='CC=gcc\ -m32\ -Wl,-rpath,[...]/i686-pc-linux-gnu/lib' +</pre></div> + +</dd> +<dt><code>--with-plugin-ld=<var>pathname</var></code></dt> +<dd><p>Enable an alternate linker to be used at link-time optimization (LTO) +link time when <samp>-fuse-linker-plugin</samp> is enabled. +This linker should have plugin support such as gold starting with +version 2.20 or GNU ld starting with version 2.21. +See <samp>-fuse-linker-plugin</samp> for details. +</p> +</dd> +<dt><code>--enable-canonical-system-headers</code></dt> +<dt><code>--disable-canonical-system-headers</code></dt> +<dd><p>Enable system header path canonicalization for <samp>libcpp</samp>. This can +produce shorter header file paths in diagnostics and dependency output +files, but these changed header paths may conflict with some compilation +environments. Enabled by default, and may be disabled using +<samp>--disable-canonical-system-headers</samp>. +</p> +</dd> +<dt><code>--with-glibc-version=<var>major</var>.<var>minor</var></code></dt> +<dd><p>Tell GCC that when the GNU C Library (glibc) is used on the target it +will be version <var>major</var>.<var>minor</var> or later. Normally this can +be detected from the C library’s header files, but this option may be +needed when bootstrapping a cross toolchain without the header files +available for building the initial bootstrap compiler. +</p> +<p>If GCC is configured with some multilibs that use glibc and some that +do not, this option applies only to the multilibs that use glibc. +However, such configurations may not work well as not all the relevant +configuration in GCC is on a per-multilib basis. +</p> +</dd> +<dt><code>--enable-as-accelerator-for=<var>target</var></code></dt> +<dd><p>Build as offload target compiler. Specify offload host triple by <var>target</var>. +</p> +</dd> +<dt><code>--enable-offload-targets=<var>target1</var>[=<var>path1</var>],…,<var>targetN</var>[=<var>pathN</var>]</code></dt> +<dd><p>Enable offloading to targets <var>target1</var>, …, <var>targetN</var>. +Offload compilers are expected to be already installed. Default search +path for them is <samp><var>exec-prefix</var></samp>, but it can be changed by +specifying paths <var>path1</var>, …, <var>pathN</var>. +</p> +<div class="smallexample"> +<pre class="smallexample">% <var>srcdir</var>/configure \ + --enable-offload-targets=amdgcn-amdhsa,nvptx-none +</pre></div> + +</dd> +<dt><code>--enable-offload-defaulted</code></dt> +<dd> +<p>Tell GCC that configured but not installed offload compilers and libgomp +plugins are silently ignored. Useful for distribution compilers where +those are in separate optional packages and where the presence or absence +of those optional packages should determine the actual supported offloading +target set rather than the GCC configure-time selection. +</p> +</dd> +<dt><code>--enable-cet</code></dt> +<dt><code>--disable-cet</code></dt> +<dd><p>Enable building target run-time libraries with control-flow +instrumentation, see <samp>-fcf-protection</samp> option. When +<code>--enable-cet</code> is specified target libraries are configured +to add <samp>-fcf-protection</samp> and, if needed, other target +specific options to a set of building options. +</p> +<p><code>--enable-cet=auto</code> is default. CET is enabled on Linux/x86 if +target binutils supports <code>Intel CET</code> instructions and disabled +otherwise. In this case, the target libraries are configured to get +additional <samp>-fcf-protection</samp> option. +</p> +</dd> +<dt><code>--with-riscv-attribute=‘<samp>yes</samp>’, ‘<samp>no</samp>’ or ‘<samp>default</samp>’</code></dt> +<dd><p>Generate RISC-V attribute by default, in order to record extra build +information in object. +</p> +<p>The option is disabled by default. It is enabled on RISC-V/ELF (bare-metal) +target if target binutils supported. +</p> +</dd> +<dt><code>--enable-s390-excess-float-precision</code></dt> +<dt><code>--disable-s390-excess-float-precision</code></dt> +<dd><p>On s390(x) targets, enable treatment of float expressions with double precision +when in standards-compliant mode (e.g., when <code>--std=c99</code> or +<code>-fexcess-precision=standard</code> are given). +</p> +<p>For a native build and cross compiles that have target headers, the option’s +default is derived from glibc’s behavior. When glibc clamps float_t to double, +GCC follows and enables the option. For other cross compiles, the default is +disabled. +</p> +</dd> +<dt><code>--with-zstd=<var>pathname</var></code></dt> +<dt><code>--with-zstd-include=<var>pathname</var></code></dt> +<dt><code>--with-zstd-lib=<var>pathname</var></code></dt> +<dd><p>If you do not have the <code>zstd</code> library installed in a standard +location and you want to build GCC, you can explicitly specify the +directory where it is installed (‘<samp>--with-zstd=<var>zstdinstalldir</var></samp>’). +The <samp>--with-zstd=<var>zstdinstalldir</var></samp> option is shorthand for +<samp>--with-zstd-lib=<var>zstdinstalldir</var>/lib</samp> and +<samp>--with-zstd-include=<var>zstdinstalldir</var>/include</samp>. If this +shorthand assumption is not correct, you can use the explicit +include and lib options directly. +</p> +<p>These flags are applicable to the host platform only. When building +a cross compiler, they will not be used to configure target libraries. +</p></dd> +</dl> + +<a name="Cross-Compiler-Specific-Options"></a> +<h4 class="subheading">Cross-Compiler-Specific Options</h4> +<p>The following options only apply to building cross compilers. +</p> +<dl compact="compact"> +<dt><code>--with-toolexeclibdir=<var>dir</var></code></dt> +<dd><p>Specify the installation directory for libraries built with a cross compiler. +The default is <samp>${gcc_tooldir}/lib</samp>. +</p> +</dd> +<dt><code>--with-sysroot</code></dt> +<dt><code>--with-sysroot=<var>dir</var></code></dt> +<dd><p>Tells GCC to consider <var>dir</var> as the root of a tree that contains +(a subset of) the root filesystem of the target operating system. +Target system headers, libraries and run-time object files will be +searched for in there. More specifically, this acts as if +<samp>--sysroot=<var>dir</var></samp> was added to the default options of the built +compiler. The specified directory is not copied into the +install tree, unlike the options <samp>--with-headers</samp> and +<samp>--with-libs</samp> that this option obsoletes. The default value, +in case <samp>--with-sysroot</samp> is not given an argument, is +<samp>${gcc_tooldir}/sys-root</samp>. If the specified directory is a +subdirectory of <samp>${exec_prefix}</samp>, then it will be found relative to +the GCC binaries if the installation tree is moved. +</p> +<p>This option affects the system root for the compiler used to build +target libraries (which runs on the build system) and the compiler newly +installed with <code>make install</code>; it does not affect the compiler which is +used to build GCC itself. +</p> +<p>If you specify the <samp>--with-native-system-header-dir=<var>dirname</var></samp> +option then the compiler will search that directory within <var>dirname</var> for +native system headers rather than the default <samp>/usr/include</samp>. +</p> +</dd> +<dt><code>--with-build-sysroot</code></dt> +<dt><code>--with-build-sysroot=<var>dir</var></code></dt> +<dd><p>Tells GCC to consider <var>dir</var> as the system root (see +<samp>--with-sysroot</samp>) while building target libraries, instead of +the directory specified with <samp>--with-sysroot</samp>. This option is +only useful when you are already using <samp>--with-sysroot</samp>. You +can use <samp>--with-build-sysroot</samp> when you are configuring with +<samp>--prefix</samp> set to a directory that is different from the one in +which you are installing GCC and your target libraries. +</p> +<p>This option affects the system root for the compiler used to build +target libraries (which runs on the build system); it does not affect +the compiler which is used to build GCC itself. +</p> +<p>If you specify the <samp>--with-native-system-header-dir=<var>dirname</var></samp> +option then the compiler will search that directory within <var>dirname</var> for +native system headers rather than the default <samp>/usr/include</samp>. +</p> +</dd> +<dt><code>--with-headers</code></dt> +<dt><code>--with-headers=<var>dir</var></code></dt> +<dd><p>Deprecated in favor of <samp>--with-sysroot</samp>. +Specifies that target headers are available when building a cross compiler. +The <var>dir</var> argument specifies a directory which has the target include +files. These include files will be copied into the <samp>gcc</samp> install +directory. <em>This option with the <var>dir</var> argument is required</em> when +building a cross compiler, if <samp><var>prefix</var>/<var>target</var>/sys-include</samp> +doesn’t pre-exist. If <samp><var>prefix</var>/<var>target</var>/sys-include</samp> does +pre-exist, the <var>dir</var> argument may be omitted. <code>fixincludes</code> +will be run on these files to make them compatible with GCC. +</p> +</dd> +<dt><code>--without-headers</code></dt> +<dd><p>Tells GCC not use any target headers from a libc when building a cross +compiler. When crossing to GNU/Linux, you need the headers so GCC +can build the exception handling for libgcc. +</p> +</dd> +<dt><code>--with-libs</code></dt> +<dt><code>--with-libs="<var>dir1</var> <var>dir2</var> … <var>dirN</var>"</code></dt> +<dd><p>Deprecated in favor of <samp>--with-sysroot</samp>. +Specifies a list of directories which contain the target runtime +libraries. These libraries will be copied into the <samp>gcc</samp> install +directory. If the directory list is omitted, this option has no +effect. +</p> +</dd> +<dt><code>--with-newlib</code></dt> +<dd><p>Specifies that ‘<samp>newlib</samp>’ is +being used as the target C library. This causes <code>__eprintf</code> to be +omitted from <samp>libgcc.a</samp> on the assumption that it will be provided by +‘<samp>newlib</samp>’. +</p> +<a name="avr"></a></dd> +<dt><code>--with-avrlibc</code></dt> +<dd><p>Only supported for the AVR target. Specifies that ‘<samp>AVR-Libc</samp>’ is +being used as the target C library. This causes float support +functions like <code>__addsf3</code> to be omitted from <samp>libgcc.a</samp> on +the assumption that it will be provided by <samp>libm.a</samp>. For more +technical details, cf. <a href="https://gcc.gnu.org/PR54461">PR54461</a>. +It is not supported for +RTEMS configurations, which currently use newlib. The option is +supported since version 4.7.2 and is the default in 4.8.0 and newer. +</p> +</dd> +<dt><code>--with-double={32|64|32,64|64,32}</code></dt> +<dt><code>--with-long-double={32|64|32,64|64,32|double}</code></dt> +<dd><p>Only supported for the AVR target since version 10. +Specify the default layout available for the C/C++ ‘<samp>double</samp>’ +and ‘<samp>long double</samp>’ type, respectively. The following rules apply: +</p><ul> +<li> The first value after the ‘<samp>=</samp>’ specifies the default layout (in bits) +of the type and also the default for the <samp>-mdouble=</samp> resp. +<samp>-mlong-double=</samp> compiler option. +</li><li> If more than one value is specified, respective multilib variants are +available, and <samp>-mdouble=</samp> resp. <samp>-mlong-double=</samp> acts +as a multilib option. +</li><li> If <samp>--with-long-double=double</samp> is specified, ‘<samp>double</samp>’ and +‘<samp>long double</samp>’ will have the same layout. +</li><li> The defaults are <samp>--with-long-double=64,32</samp> and +<samp>--with-double=32,64</samp>. The default ‘<samp>double</samp>’ layout imposed by +the latter is compatible with older versions of the compiler that implement +‘<samp>double</samp>’ as a 32-bit type, which does not comply to the language standard. +</li></ul> +<p>Not all combinations of <samp>--with-double=</samp> and +<samp>--with-long-double=</samp> are valid. For example, the combination +<samp>--with-double=32,64</samp> <samp>--with-long-double=32</samp> will be +rejected because the first option specifies the availability of +multilibs for ‘<samp>double</samp>’, whereas the second option implies +that ‘<samp>long double</samp>’ — and hence also ‘<samp>double</samp>’ — is always +32 bits wide. +</p> +</dd> +<dt><code>--with-double-comparison={tristate|bool|libf7}</code></dt> +<dd><p>Only supported for the AVR target since version 10. +Specify what result format is returned by library functions that +compare 64-bit floating point values (<code>DFmode</code>). +The GCC default is ‘<samp>tristate</samp>’. If the floating point +implementation returns a boolean instead, set it to ‘<samp>bool</samp>’. +</p> +</dd> +<dt><code>--with-libf7={libgcc|math|math-symbols|no}</code></dt> +<dd><p>Only supported for the AVR target since version 10. +Specify to which degree code from LibF7 is included in libgcc. +LibF7 is an ad-hoc, AVR-specific, 64-bit floating point emulation +written in C and (inline) assembly. ‘<samp>libgcc</samp>’ adds support +for functions that one would usually expect in libgcc like double addition, +double comparisons and double conversions. ‘<samp>math</samp>’ also adds routines +that one would expect in <samp>libm.a</samp>, but with <code>__</code> (two underscores) +prepended to the symbol names as specified by <samp>math.h</samp>. +‘<samp>math-symbols</samp>’ also defines weak aliases for the functions +declared in <samp>math.h</samp>. However, <code>--with-libf7</code> won’t +install no <samp>math.h</samp> header file whatsoever, this file must come +from elsewhere. This option sets <samp>--with-double-comparison</samp> +to ‘<samp>bool</samp>’. +</p> +</dd> +<dt><code>--with-nds32-lib=<var>library</var></code></dt> +<dd><p>Specifies that <var>library</var> setting is used for building <samp>libgcc.a</samp>. +Currently, the valid <var>library</var> is ‘<samp>newlib</samp>’ or ‘<samp>mculib</samp>’. +This option is only supported for the NDS32 target. +</p> +</dd> +<dt><code>--with-build-time-tools=<var>dir</var></code></dt> +<dd><p>Specifies where to find the set of target tools (assembler, linker, etc.) +that will be used while building GCC itself. This option can be useful +if the directory layouts are different between the system you are building +GCC on, and the system where you will deploy it. +</p> +<p>For example, on an ‘<samp>ia64-hp-hpux</samp>’ system, you may have the GNU +assembler and linker in <samp>/usr/bin</samp>, and the native tools in a +different path, and build a toolchain that expects to find the +native tools in <samp>/usr/bin</samp>. +</p> +<p>When you use this option, you should ensure that <var>dir</var> includes +<code>ar</code>, <code>as</code>, <code>ld</code>, <code>nm</code>, +<code>ranlib</code> and <code>strip</code> if necessary, and possibly +<code>objdump</code>. Otherwise, GCC may use an inconsistent set of +tools. +</p></dd> +</dl> + +<a name="Overriding-configure-test-results"></a> +<h4 class="subsubheading">Overriding <code>configure</code> test results</h4> + +<p>Sometimes, it might be necessary to override the result of some +<code>configure</code> test, for example in order to ease porting to a new +system or work around a bug in a test. The toplevel <code>configure</code> +script provides three variables for this: +</p> +<dl compact="compact"> +<dd> +<a name="index-build_005fconfigargs"></a> +</dd> +<dt><code>build_configargs</code></dt> +<dd><p>The contents of this variable is passed to all build <code>configure</code> +scripts. +</p> +<a name="index-host_005fconfigargs"></a> +</dd> +<dt><code>host_configargs</code></dt> +<dd><p>The contents of this variable is passed to all host <code>configure</code> +scripts. +</p> +<a name="index-target_005fconfigargs"></a> +</dd> +<dt><code>target_configargs</code></dt> +<dd><p>The contents of this variable is passed to all target <code>configure</code> +scripts. +</p> +</dd> +</dl> + +<p>In order to avoid shell and <code>make</code> quoting issues for complex +overrides, you can pass a setting for <code>CONFIG_SITE</code> and set +variables in the site file. +</p> +<a name="Objective-C-Specific-Options"></a> +<h4 class="subheading">Objective-C-Specific Options</h4> + +<p>The following options apply to the build of the Objective-C runtime library. +</p> +<dl compact="compact"> +<dt><code>--enable-objc-gc</code></dt> +<dd><p>Specify that an additional variant of the GNU Objective-C runtime library +is built, using an external build of the Boehm-Demers-Weiser garbage +collector (<a href="https://www.hboehm.info/gc/">https://www.hboehm.info/gc/</a>). This library needs to be +available for each multilib variant, unless configured with +<samp>--enable-objc-gc=‘<samp>auto</samp>’</samp> in which case the build of the +additional runtime library is skipped when not available and the build +continues. +</p> +</dd> +<dt><code>--with-target-bdw-gc=<var>list</var></code></dt> +<dt><code>--with-target-bdw-gc-include=<var>list</var></code></dt> +<dt><code>--with-target-bdw-gc-lib=<var>list</var></code></dt> +<dd><p>Specify search directories for the garbage collector header files and +libraries. <var>list</var> is a comma separated list of key value pairs of the +form ‘<samp><var>multilibdir</var>=<var>path</var></samp>’, where the default multilib key +is named as ‘<samp>.</samp>’ (dot), or is omitted (e.g. +‘<samp>--with-target-bdw-gc=/opt/bdw-gc,32=/opt-bdw-gc32</samp>’). +</p> +<p>The options <samp>--with-target-bdw-gc-include</samp> and +<samp>--with-target-bdw-gc-lib</samp> must always be specified together +for each multilib variant and they take precedence over +<samp>--with-target-bdw-gc</samp>. If <samp>--with-target-bdw-gc-include</samp> +is missing values for a multilib, then the value for the default +multilib is used (e.g. ‘<samp>--with-target-bdw-gc-include=/opt/bdw-gc/include</samp>’ +‘<samp>--with-target-bdw-gc-lib=/opt/bdw-gc/lib64,32=/opt-bdw-gc/lib32</samp>’). +If none of these options are specified, the library is assumed in +default locations. +</p></dd> +</dl> + +<a name="D-Specific-Options"></a> +<h4 class="subheading">D-Specific Options</h4> + +<p>The following options apply to the build of the D runtime library. +</p> +<dl compact="compact"> +<dt><code>--enable-libphobos-checking</code></dt> +<dt><code>--disable-libphobos-checking</code></dt> +<dt><code>--enable-libphobos-checking=<var>list</var></code></dt> +<dd><p>This option controls whether run-time checks and contracts are compiled into +the D runtime library. When the option is not specified, the library is built +with ‘<samp>release</samp>’ checking. When the option is specified without a +<var>list</var>, the result is the same as ‘<samp>--enable-libphobos-checking=yes</samp>’. +Likewise, ‘<samp>--disable-libphobos-checking</samp>’ is equivalent to +‘<samp>--enable-libphobos-checking=no</samp>’. +</p> +<p>The categories of checks available in <var>list</var> are ‘<samp>yes</samp>’ (compiles +libphobos with <samp>-fno-release</samp>), ‘<samp>no</samp>’ (compiles libphobos with +<samp>-frelease</samp>), ‘<samp>all</samp>’ (same as ‘<samp>yes</samp>’), ‘<samp>none</samp>’ or +‘<samp>release</samp>’ (same as ‘<samp>no</samp>’). +</p> +<p>Individual checks available in <var>list</var> are ‘<samp>assert</samp>’ (compiles libphobos +with an extra option <samp>-fassert</samp>). +</p> +</dd> +<dt><code>--with-libphobos-druntime-only</code></dt> +<dt><code>--with-libphobos-druntime-only=<var>choice</var></code></dt> +<dd><p>Specify whether to build only the core D runtime library (druntime), or both +the core and standard library (phobos) into libphobos. This is useful for +targets that have full support in druntime, but no or incomplete support +in phobos. <var>choice</var> can be one of ‘<samp>auto</samp>’, ‘<samp>yes</samp>’, and ‘<samp>no</samp>’ +where ‘<samp>auto</samp>’ is the default. +</p> +<p>When the option is not specified, the default choice ‘<samp>auto</samp>’ means that it +is inferred whether the target has support for the phobos standard library. +When the option is specified without a <var>choice</var>, the result is the same as +‘<samp>--with-libphobos-druntime-only=yes</samp>’. +</p> +</dd> +<dt><code>--with-target-system-zlib</code></dt> +<dd><p>Use installed ‘<samp>zlib</samp>’ rather than that included with GCC. This needs +to be available for each multilib variant, unless configured with +<samp>--with-target-system-zlib=‘<samp>auto</samp>’</samp> in which case the GCC included +‘<samp>zlib</samp>’ is only used when the system installed library is not available. +</p></dd> +</dl> + +<hr /> +<p><p><a href="./index.html">Return to the GCC Installation page</a> +</p> + + + + + + + + + + +</body> +</html> |