toolchain/gcc/INSTALL/configure.html

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  42 <h1 class="settitle">Installing GCC: Configuration</h1>
  43 <a name="index-Configuration-1"></a><a name="index-Installing-GCC_003a-Configuration-2"></a>
  44 Like most GNU software, GCC must be configured before it can be built.
  45 This document describes the recommended configuration procedure
  46 for both native and cross targets.
  47
  48    <p>We use <var>srcdir</var> to refer to the toplevel source directory for
  49 GCC; we use <var>objdir</var> to refer to the toplevel build/object directory.
  50
  51    <p>If you obtained the sources via CVS, <var>srcdir</var> must refer to the top
  52 <span class="file">gcc</span> directory, the one where the <span class="file">MAINTAINERS</span> can be found,
  53 and not its <span class="file">gcc</span> subdirectory, otherwise the build will fail.
  54
  55    <p>If either <var>srcdir</var> or <var>objdir</var> is located on an automounted NFS
  56 file system, the shell's built-in <span class="command">pwd</span> command will return
  57 temporary pathnames.  Using these can lead to various sorts of build
  58 problems.  To avoid this issue, set the <span class="env">PWDCMD</span> environment
  59 variable to an automounter-aware <span class="command">pwd</span> command, e.g.,
  60 <span class="command">pawd</span> or <span class="samp">amq -w</span>, during the configuration and build
  61 phases.
  62
  63    <p>First, we <strong>highly</strong> recommend that GCC be built into a
  64 separate directory than the sources which does <strong>not</strong> reside
  65 within the source tree.  This is how we generally build GCC; building
  66 where <var>srcdir</var> == <var>objdir</var> should still work, but doesn't
  67 get extensive testing; building where <var>objdir</var> is a subdirectory
  68 of <var>srcdir</var> is unsupported.
  69
  70    <p>If you have previously built GCC in the same directory for a
  71 different target machine, do <span class="samp">make distclean</span> to delete all files
  72 that might be invalid.  One of the files this deletes is <span class="file">Makefile</span>;
  73 if <span class="samp">make distclean</span> complains that <span class="file">Makefile</span> does not exist
  74 or issues a message like &ldquo;don't know how to make distclean&rdquo; it probably
  75 means that the directory is already suitably clean.  However, with the
  76 recommended method of building in a separate <var>objdir</var>, you should
  77 simply use a different <var>objdir</var> for each target.
  78
  79    <p>Second, when configuring a native system, either <span class="command">cc</span> or
  80 <span class="command">gcc</span> must be in your path or you must set <span class="env">CC</span> in
  81 your environment before running configure.  Otherwise the configuration
  82 scripts may fail.
  83
  84    <p>Note that the bootstrap compiler and the resulting GCC must be link
  85 compatible, else the bootstrap will fail with linker errors about
  86 incompatible object file formats.  Several multilibed targets are
  87 affected by this requirement, see
  88 <a href="specific.html">host/target specific installation notes</a>.
  89
  90    <p>To configure GCC:
  91
  92 <pre class="smallexample">        % mkdir <var>objdir</var>
  93         % cd <var>objdir</var>
  94         % <var>srcdir</var>/configure [<var>options</var>] [<var>target</var>]
  95 </pre>
  96    <h3 class="heading"><a name="TOC0"></a>Target specification</h3>
  97
  98      <ul>
  99 <li>GCC has code to correctly determine the correct value for <var>target</var>
 100 for nearly all native systems.  Therefore, we highly recommend you not
 101 provide a configure target when configuring a native compiler.
 102
 103      <li><var>target</var> must be specified as <span class="option">--target=</span><var>target</var>
 104 when configuring a cross compiler; examples of valid targets would be
 105 i960-rtems, m68k-coff, sh-elf, etc.
 106
 107      <li>Specifying just <var>target</var> instead of <span class="option">--target=</span><var>target</var>
 108 implies that the host defaults to <var>target</var>.
 109 </ul>
 110
 111 <h3 class="heading"><a name="TOC1"></a>Options specification</h3>
 112
 113 <p>Use <var>options</var> to override several configure time options for
 114 GCC.  A list of supported <var>options</var> follows; <span class="samp">configure
 115 --help</span> may list other options, but those not listed below may not
 116 work and should not normally be used.
 117
 118    <p>Note that each <span class="option">--enable</span> option has a corresponding
 119 <span class="option">--disable</span> option and that each <span class="option">--with</span> option has a
 120 corresponding <span class="option">--without</span> option.
 121
 122      <dl>
 123 <dt><code>--prefix=</code><var>dirname</var><dd>Specify the toplevel installation
 124 directory.  This is the recommended way to install the tools into a directory
 125 other than the default.  The toplevel installation directory defaults to
 126 <span class="file">/usr/local</span>.
 127
 128      <p>We <strong>highly</strong> recommend against <var>dirname</var> being the same or a
 129 subdirectory of <var>objdir</var> or vice versa.  If specifying a directory
 130 beneath a user's home directory tree, some shells will not expand
 131 <var>dirname</var> correctly if it contains the <span class="samp">~</span> metacharacter; use
 132 <span class="env">$HOME</span> instead.
 133
 134      <p>The following standard <span class="command">autoconf</span> options are supported.  Normally you
 135 should not need to use these options.
 136           <dl>
 137 <dt><code>--exec-prefix=</code><var>dirname</var><dd>Specify the toplevel installation directory for architecture-dependent
 138 files.  The default is <var>prefix</var>.
 139
 140           <br><dt><code>--bindir=</code><var>dirname</var><dd>Specify the installation directory for the executables called by users
 141 (such as <span class="command">gcc</span> and <span class="command">g++</span>).  The default is
 142 <var>exec-prefix</var><span class="file">/bin</span>.
 143
 144           <br><dt><code>--libdir=</code><var>dirname</var><dd>Specify the installation directory for object code libraries and
 145 internal data files of GCC.  The default is <var>exec-prefix</var><span class="file">/lib</span>.
 146
 147           <br><dt><code>--libexecdir=</code><var>dirname</var><dd>Specify the installation directory for internal executables of GCC.
 148   The default is <var>exec-prefix</var><span class="file">/libexec</span>.
 149
 150           <br><dt><code>--with-slibdir=</code><var>dirname</var><dd>Specify the installation directory for the shared libgcc library.  The
 151 default is <var>libdir</var>.
 152
 153           <br><dt><code>--infodir=</code><var>dirname</var><dd>Specify the installation directory for documentation in info format.
 154 The default is <var>prefix</var><span class="file">/info</span>.
 155
 156           <br><dt><code>--datadir=</code><var>dirname</var><dd>Specify the installation directory for some architecture-independent
 157 data files referenced by GCC.  The default is <var>prefix</var><span class="file">/share</span>.
 158
 159           <br><dt><code>--mandir=</code><var>dirname</var><dd>Specify the installation directory for manual pages.  The default is
 160 <var>prefix</var><span class="file">/man</span>.  (Note that the manual pages are only extracts from
 161 the full GCC manuals, which are provided in Texinfo format.  The manpages
 162 are derived by an automatic conversion process from parts of the full
 163 manual.)
 164
 165           <br><dt><code>--with-gxx-include-dir=</code><var>dirname</var><dd>Specify
 166 the installation directory for G++ header files.  The default is
 167 <var>prefix</var><span class="file">/include/c++/</span><var>version</var>.
 168
 169      </dl>
 170
 171      <br><dt><code>--program-prefix=</code><var>prefix</var><dd>GCC supports some transformations of the names of its programs when
 172 installing them. This option prepends <var>prefix</var> to the names of
 173 programs to install in <var>bindir</var> (see above). For example, specifying
 174 <span class="option">--program-prefix=foo-</span> would result in <span class="samp">gcc</span>
 175 being installed as <span class="file">/usr/local/bin/foo-gcc</span>.
 176
 177      <br><dt><code>--program-suffix=</code><var>suffix</var><dd>Appends <var>suffix</var> to the names of programs to install in <var>bindir</var>
 178 (see above). For example, specifying <span class="option">--program-suffix=-3.1</span>
 179 would result in <span class="samp">gcc</span> being installed as
 180 <span class="file">/usr/local/bin/gcc-3.1</span>.
 181
 182      <br><dt><code>--program-transform-name=</code><var>pattern</var><dd>Applies the <span class="samp">sed</span> script <var>pattern</var> to be applied to the names
 183 of programs to install in <var>bindir</var> (see above). <var>pattern</var> has to
 184 consist of one or more basic <span class="samp">sed</span> editing commands, separated by
 185 semicolons. For example, if you want the <span class="samp">gcc</span> program name to be
 186 transformed to the installed program <span class="file">/usr/local/bin/myowngcc</span> and
 187 the <span class="samp">g++</span> program name to be transformed to
 188 <span class="file">/usr/local/bin/gspecial++</span> without changing other program names,
 189 you could use the pattern
 190 <span class="option">--program-transform-name='s/^gcc$/myowngcc/; s/^g++$/gspecial++/'</span>
 191 to achieve this effect.
 192
 193      <p>All three options can be combined and used together, resulting in more
 194 complex conversion patterns. As a basic rule, <var>prefix</var> (and
 195 <var>suffix</var>) are prepended (appended) before further transformations
 196 can happen with a special transformation script <var>pattern</var>.
 197
 198      <p>As currently implemented, this option only takes effect for native
 199 builds; cross compiler binaries' names are not transformed even when a
 200 transformation is explicitly asked for by one of these options.
 201
 202      <p>For native builds, some of the installed programs are also installed
 203 with the target alias in front of their name, as in
 204 <span class="samp">i686-pc-linux-gnu-gcc</span>. All of the above transformations happen
 205 before the target alias is prepended to the name - so, specifying
 206 <span class="option">--program-prefix=foo-</span> and <span class="option">program-suffix=-3.1</span>, the
 207 resulting binary would be installed as
 208 <span class="file">/usr/local/bin/i686-pc-linux-gnu-foo-gcc-3.1</span>.
 209
 210      <p>As a last shortcoming, none of the installed Ada programs are
 211 transformed yet, which will be fixed in some time.
 212
 213      <br><dt><code>--with-local-prefix=</code><var>dirname</var><dd>Specify the
 214 installation directory for local include files.  The default is
 215 <span class="file">/usr/local</span>.  Specify this option if you want the compiler to
 216 search directory <var>dirname</var><span class="file">/include</span> for locally installed
 217 header files <em>instead</em> of <span class="file">/usr/local/include</span>.
 218
 219      <p>You should specify <span class="option">--with-local-prefix</span> <strong>only</strong> if your
 220 site has a different convention (not <span class="file">/usr/local</span>) for where to put
 221 site-specific files.
 222
 223      <p>The default value for <span class="option">--with-local-prefix</span> is <span class="file">/usr/local</span>
 224 regardless of the value of <span class="option">--prefix</span>.  Specifying
 225 <span class="option">--prefix</span> has no effect on which directory GCC searches for
 226 local header files.  This may seem counterintuitive, but actually it is
 227 logical.
 228
 229      <p>The purpose of <span class="option">--prefix</span> is to specify where to <em>install
 230 GCC</em>.  The local header files in <span class="file">/usr/local/include</span>&mdash;if you put
 231 any in that directory&mdash;are not part of GCC.  They are part of other
 232 programs&mdash;perhaps many others.  (GCC installs its own header files in
 233 another directory which is based on the <span class="option">--prefix</span> value.)
 234
 235      <p>Both the local-prefix include directory and the GCC-prefix include
 236 directory are part of GCC's "system include" directories.  Although these
 237 two directories are not fixed, they need to be searched in the proper
 238 order for the correct processing of the include_next directive.  The
 239 local-prefix include directory is searched before the GCC-prefix
 240 include directory.  Another characteristic of system include directories
 241 is that pedantic warnings are turned off for headers in these directories.
 242
 243      <p>Some autoconf macros add <span class="option">-I </span><var>directory</var> options to the
 244 compiler command line, to ensure that directories containing installed
 245 packages' headers are searched.  When <var>directory</var> is one of GCC's
 246 system include directories, GCC will ignore the option so that system
 247 directories continue to be processed in the correct order.  This
 248 may result in a search order different from what was specified but the
 249 directory will still be searched.
 250
 251      <p>GCC automatically searches for ordinary libraries using
 252 <span class="env">GCC_EXEC_PREFIX</span>.  Thus, when the same installation prefix is
 253 used for both GCC and packages, GCC will automatically search for
 254 both headers and libraries.  This provides a configuration that is
 255 easy to use.  GCC behaves in a manner similar to that when it is
 256 installed as a system compiler in <span class="file">/usr</span>.
 257
 258      <p>Sites that need to install multiple versions of GCC may not want to
 259 use the above simple configuration.  It is possible to use the
 260 <span class="option">--program-prefix</span>, <span class="option">--program-suffix</span> and
 261 <span class="option">--program-transform-name</span> options to install multiple versions
 262 into a single directory, but it may be simpler to use different prefixes
 263 and the <span class="option">--with-local-prefix</span> option to specify the location of the
 264 site-specific files for each version.  It will then be necessary for
 265 users to specify explicitly the location of local site libraries
 266 (e.g., with <span class="env">LIBRARY_PATH</span>).
 267
 268      <p>The same value can be used for both <span class="option">--with-local-prefix</span> and
 269 <span class="option">--prefix</span> provided it is not <span class="file">/usr</span>.  This can be used
 270 to avoid the default search of <span class="file">/usr/local/include</span>.
 271
 272      <p><strong>Do not</strong> specify <span class="file">/usr</span> as the <span class="option">--with-local-prefix</span>!
 273 The directory you use for <span class="option">--with-local-prefix</span> <strong>must not</strong>
 274 contain any of the system's standard header files.  If it did contain
 275 them, certain programs would be miscompiled (including GNU Emacs, on
 276 certain targets), because this would override and nullify the header
 277 file corrections made by the <span class="command">fixincludes</span> script.
 278
 279      <p>Indications are that people who use this option use it based on mistaken
 280 ideas of what it is for.  People use it as if it specified where to
 281 install part of GCC.  Perhaps they make this assumption because
 282 installing GCC creates the directory.
 283
 284      <br><dt><code>--enable-shared[=</code><var>package</var><code>[,...]]</code><dd>Build shared versions of libraries, if shared libraries are supported on
 285 the target platform.  Unlike GCC 2.95.x and earlier, shared libraries
 286 are enabled by default on all platforms that support shared libraries,
 287 except for <span class="samp">libobjc</span> which is built as a static library only by
 288 default.
 289
 290      <p>If a list of packages is given as an argument, build shared libraries
 291 only for the listed packages.  For other packages, only static libraries
 292 will be built.  Package names currently recognized in the GCC tree are
 293 <span class="samp">libgcc</span> (also known as <span class="samp">gcc</span>), <span class="samp">libstdc++</span> (not
 294 <span class="samp">libstdc++-v3</span>), <span class="samp">libffi</span>, <span class="samp">zlib</span>, <span class="samp">boehm-gc</span> and
 295 <span class="samp">libjava</span>.  Note that <span class="samp">libobjc</span> does not recognize itself by
 296 any name, so, if you list package names in <span class="option">--enable-shared</span>,
 297 you will only get static Objective-C libraries.  <span class="samp">libf2c</span> and
 298 <span class="samp">libiberty</span> do not support shared libraries at all.
 299
 300      <p>Use <span class="option">--disable-shared</span> to build only static libraries.  Note that
 301 <span class="option">--disable-shared</span> does not accept a list of package names as
 302 argument, only <span class="option">--enable-shared</span> does.
 303
 304      <br><dt><code><a name="with_002dgnu_002das"></a>--with-gnu-as</code><dd>Specify that the compiler should assume that the
 305 assembler it finds is the GNU assembler.  However, this does not modify
 306 the rules to find an assembler and will result in confusion if the
 307 assembler found is not actually the GNU assembler.  (Confusion may also
 308 result if the compiler finds the GNU assembler but has not been
 309 configured with <span class="option">--with-gnu-as</span>.)  If you have more than one
 310 assembler installed on your system, you may want to use this option in
 311 connection with <span class="option">--with-as=</span><var>pathname</var>.
 312
 313      <p>The following systems are the only ones where it makes a difference
 314 whether you use the GNU assembler.  On any other system,
 315 <span class="option">--with-gnu-as</span> has no effect.
 316
 317           <ul>
 318 <li><span class="samp">hppa1.0-</span><var>any</var><span class="samp">-</span><var>any</var>
 319 <li><span class="samp">hppa1.1-</span><var>any</var><span class="samp">-</span><var>any</var>
 320 <li><span class="samp">i386-</span><var>any</var><span class="samp">-sysv</span>
 321 <li><span class="samp">m68k-bull-sysv</span>
 322 <li><span class="samp">m68k-hp-hpux</span>
 323 <li><span class="samp">m68000-hp-hpux</span>
 324 <li><span class="samp">m68000-att-sysv</span>
 325 <li><var>any</var><span class="samp">-lynx-lynxos</span>
 326 <li><span class="samp">mips-</span><var>any</var>
 327 <li><span class="samp">sparc-sun-solaris2.</span><var>any</var>
 328 <li><span class="samp">sparc64-</span><var>any</var><span class="samp">-solaris2.</span><var>any</var>
 329 </ul>
 330
 331      <p>On the systems listed above (except for the HP-PA, the SPARC, for ISC on
 332 the 386, and for <span class="samp">mips-sgi-irix5.*</span>), if you use the GNU assembler,
 333 you should also use the GNU linker (and specify <span class="option">--with-gnu-ld</span>).
 334
 335      <br><dt><code><a name="with_002das"></a>--with-as=</code><var>pathname</var><dd>Specify that the
 336 compiler should use the assembler pointed to by <var>pathname</var>, rather
 337 than the one found by the standard rules to find an assembler, which
 338 are:
 339           <ul>
 340 <li>Check the <var>libexec</var><span class="file">/gcc/</span><var>target</var><span class="file">/</span><var>version</var>
 341 directory, where <var>libexec</var> defaults to
 342 <var>exec-prefix</var><span class="file">/libexec</span> and <var>exec-prefix</var> defaults to
 343 <var>prefix</var> which defaults to <span class="file">/usr/local</span> unless overridden by
 344 the <span class="option">--prefix=</span><var>pathname</var> switch described
 345 above. <var>target</var> is the target system triple, such as
 346 <span class="samp">sparc-sun-solaris2.7</span>, and <var>version</var> denotes the GCC
 347 version, such as 3.0.
 348 <li>Check operating system specific directories (e.g. <span class="file">/usr/ccs/bin</span> on
 349 Sun Solaris 2).
 350 </ul>
 351      Note that these rules do not check for the value of <span class="env">PATH</span>.  You may
 352 want to use <span class="option">--with-as</span> if no assembler is installed in the
 353 directories listed above, or if you have multiple assemblers installed
 354 and want to choose one that is not found by the above rules.
 355
 356      <br><dt><code><a name="with_002dgnu_002dld"></a>--with-gnu-ld</code><dd>Same as <a href="#with-gnu-as"><span class="option">--with-gnu-as</span></a>
 357 but for the linker.
 358
 359      <br><dt><code>--with-ld=</code><var>pathname</var><dd>Same as <a href="#with-as"><span class="option">--with-as</span></a>
 360 but for the linker.
 361
 362      <br><dt><code>--with-stabs</code><dd>Specify that stabs debugging
 363 information should be used instead of whatever format the host normally
 364 uses.  Normally GCC uses the same debug format as the host system.
 365
 366      <p>On MIPS based systems and on Alphas, you must specify whether you want
 367 GCC to create the normal ECOFF debugging format, or to use BSD-style
 368 stabs passed through the ECOFF symbol table.  The normal ECOFF debug
 369 format cannot fully handle languages other than C.  BSD stabs format can
 370 handle other languages, but it only works with the GNU debugger GDB.
 371
 372      <p>Normally, GCC uses the ECOFF debugging format by default; if you
 373 prefer BSD stabs, specify <span class="option">--with-stabs</span> when you configure GCC.
 374
 375      <p>No matter which default you choose when you configure GCC, the user
 376 can use the <span class="option">-gcoff</span> and <span class="option">-gstabs+</span> options to specify explicitly
 377 the debug format for a particular compilation.
 378
 379      <p><span class="option">--with-stabs</span> is meaningful on the ISC system on the 386, also, if
 380 <span class="option">--with-gas</span> is used.  It selects use of stabs debugging
 381 information embedded in COFF output.  This kind of debugging information
 382 supports C++ well; ordinary COFF debugging information does not.
 383
 384      <p><span class="option">--with-stabs</span> is also meaningful on 386 systems running SVR4.  It
 385 selects use of stabs debugging information embedded in ELF output.  The
 386 C++ compiler currently (2.6.0) does not support the DWARF debugging
 387 information normally used on 386 SVR4 platforms; stabs provide a
 388 workable alternative.  This requires gas and gdb, as the normal SVR4
 389 tools can not generate or interpret stabs.
 390
 391      <br><dt><code>--disable-multilib</code><dd>Specify that multiple target
 392 libraries to support different target variants, calling
 393 conventions, etc should not be built.  The default is to build a
 394 predefined set of them.
 395
 396      <p>Some targets provide finer-grained control over which multilibs are built
 397 (e.g., <span class="option">--disable-softfloat</span>):
 398           <dl>
 399 <dt><code>arc-*-elf*</code><dd>biendian.
 400
 401           <br><dt><code>arm-*-*</code><dd>fpu, 26bit, underscore, interwork, biendian, nofmult.
 402
 403           <br><dt><code>m68*-*-*</code><dd>softfloat, m68881, m68000, m68020.
 404
 405           <br><dt><code>mips*-*-*</code><dd>single-float, biendian, softfloat.
 406
 407           <br><dt><code>powerpc*-*-*, rs6000*-*-*</code><dd>aix64, pthread, softfloat, powercpu, powerpccpu, powerpcos, biendian,
 408 sysv, aix.
 409
 410      </dl>
 411
 412      <br><dt><code>--enable-threads</code><dd>Specify that the target
 413 supports threads.  This affects the Objective-C compiler and runtime
 414 library, and exception handling for other languages like C++ and Java.
 415 On some systems, this is the default.
 416
 417      <p>In general, the best (and, in many cases, the only known) threading
 418 model available will be configured for use.  Beware that on some
 419 systems, GCC has not been taught what threading models are generally
 420 available for the system.  In this case, <span class="option">--enable-threads</span> is an
 421 alias for <span class="option">--enable-threads=single</span>.
 422
 423      <br><dt><code>--disable-threads</code><dd>Specify that threading support should be disabled for the system.
 424 This is an alias for <span class="option">--enable-threads=single</span>.
 425
 426      <br><dt><code>--enable-threads=</code><var>lib</var><dd>Specify that
 427 <var>lib</var> is the thread support library.  This affects the Objective-C
 428 compiler and runtime library, and exception handling for other languages
 429 like C++ and Java.  The possibilities for <var>lib</var> are:
 430
 431           <dl>
 432 <dt><code>aix</code><dd>AIX thread support.
 433 <br><dt><code>dce</code><dd>DCE thread support.
 434 <br><dt><code>gnat</code><dd>Ada tasking support.  For non-Ada programs, this setting is equivalent
 435 to <span class="samp">single</span>. When used in conjunction with the Ada run time, it
 436 causes GCC to use the same thread primitives as Ada uses.  This option
 437 is necessary when using both Ada and the back end exception handling,
 438 which is the default for most Ada targets.
 439 <br><dt><code>mach</code><dd>Generic MACH thread support, known to work on NeXTSTEP.  (Please note
 440 that the file needed to support this configuration, <span class="file">gthr-mach.h</span>, is
 441 missing and thus this setting will cause a known bootstrap failure.)
 442 <br><dt><code>no</code><dd>This is an alias for <span class="samp">single</span>.
 443 <br><dt><code>posix</code><dd>Generic POSIX thread support.
 444 <br><dt><code>rtems</code><dd>RTEMS thread support.
 445 <br><dt><code>single</code><dd>Disable thread support, should work for all platforms.
 446 <br><dt><code>solaris</code><dd>Sun Solaris 2 thread support.
 447 <br><dt><code>vxworks</code><dd>VxWorks thread support.
 448 <br><dt><code>win32</code><dd>Microsoft Win32 API thread support.
 449 </dl>
 450
 451      <br><dt><code>--with-cpu=</code><var>cpu</var><dd>Specify which cpu variant the compiler should generate code for by default.
 452 <var>cpu</var> will be used as the default value of the <span class="option">-mcpu=</span> switch.
 453 This option is only supported on some targets, including ARM, i386, PowerPC,
 454 and SPARC.
 455
 456      <br><dt><code>--with-schedule=</code><var>cpu</var><dt><code>--with-arch=</code><var>cpu</var><dt><code>--with-tune=</code><var>cpu</var><dt><code>--with-abi=</code><var>abi</var><dt><code>--with-float=</code><var>type</var><dd>These configure options provide default values for the <span class="option">-mschedule=</span>,
 457 <span class="option">-march=</span>, <span class="option">-mtune=</span>, and <span class="option">-mabi=</span> options and for
 458 <span class="option">-mhard-float</span> or <span class="option">-msoft-float</span>.  As with <span class="option">--with-cpu</span>,
 459 which switches will be accepted and acceptable values of the arguments depend
 460 on the target.
 461
 462      <br><dt><code>--enable-altivec</code><dd>Specify that the target supports AltiVec vector enhancements.  This
 463 option will adjust the ABI for AltiVec enhancements, as well as generate
 464 AltiVec code when appropriate.  This option is only available for
 465 PowerPC systems.
 466
 467      <br><dt><code>--enable-__cxa_atexit</code><dd>Define if you want to use __cxa_atexit, rather than atexit, to
 468 register C++ destructors for local statics and global objects.
 469 This is essential for fully standards-compliant handling of
 470 destructors, but requires __cxa_atexit in libc. This option is currently
 471 only available on systems with GNU libc. When enabled, this will cause
 472 <span class="option">-fuse-cxa-exit</span> to be passed by default.
 473
 474      <br><dt><code>--enable-target-optspace</code><dd>Specify that target
 475 libraries should be optimized for code space instead of code speed.
 476 This is the default for the m32r platform.
 477
 478      <br><dt><code>--disable-cpp</code><dd>Specify that a user visible <span class="command">cpp</span> program should not be installed.
 479
 480      <br><dt><code>--with-cpp-install-dir=</code><var>dirname</var><dd>Specify that the user visible <span class="command">cpp</span> program should be installed
 481 in <var>prefix</var><span class="file">/</span><var>dirname</var><span class="file">/cpp</span>, in addition to <var>bindir</var>.
 482
 483      <br><dt><code>--enable-initfini-array</code><dd>Force the use of sections <code>.init_array</code> and <code>.fini_array</code>
 484 (instead of <code>.init</code> and <code>.fini</code>) for constructors and
 485 destructors.  Option <span class="option">--disable-initfini-array</span> has the
 486 opposite effect.  If neither option is specified, the configure script
 487 will try to guess whether the <code>.init_array</code> and
 488 <code>.fini_array</code> sections are supported and, if they are, use them.
 489
 490      <br><dt><code>--enable-maintainer-mode</code><dd>The build rules that
 491 regenerate the GCC master message catalog <span class="file">gcc.pot</span> are normally
 492 disabled.  This is because it can only be rebuilt if the complete source
 493 tree is present.  If you have changed the sources and want to rebuild the
 494 catalog, configuring with <span class="option">--enable-maintainer-mode</span> will enable
 495 this.  Note that you need a recent version of the <code>gettext</code> tools
 496 to do so.
 497
 498      <br><dt><code>--enable-generated-files-in-srcdir</code><dd>Neither the .c and .h files that are generated from bison and flex nor the
 499 info manuals and man pages that are built from the .texi files are present
 500 in the CVS development tree.  When building GCC from that development tree,
 501 or from a snapshot which are created from CVS, then those generated files
 502 are placed in your build directory, which allows for the source to be in a
 503 readonly directory.
 504
 505      <p>If you configure with <span class="option">--enable-generated-files-in-srcdir</span> then those
 506 generated files will go into the source directory.  This is mainly intended
 507 for generating release or prerelease tarballs of the GCC sources, since it
 508 is not a requirement that the users of source releases to have flex, bison, or
 509 makeinfo.
 510
 511      <br><dt><code>--enable-version-specific-runtime-libs</code><dd>Specify
 512 that runtime libraries should be installed in the compiler specific
 513 subdirectory (<var>libdir</var><span class="file">/gcc</span>) rather than the usual places.  In
 514 addition, <span class="samp">libstdc++</span>'s include files will be installed into
 515 <var>libdir</var> unless you overruled it by using
 516 <span class="option">--with-gxx-include-dir=</span><var>dirname</var>.  Using this option is
 517 particularly useful if you intend to use several versions of GCC in
 518 parallel. This is currently supported by <span class="samp">libf2c</span> and
 519 <span class="samp">libstdc++</span>, and is the default for <span class="samp">libobjc</span> which cannot be
 520 changed in this case.
 521
 522      <br><dt><code>--enable-languages=</code><var>lang1</var><code>,</code><var>lang2</var><code>,...</code><dd>Specify that only a particular subset of compilers and
 523 their runtime libraries should be built.  For a list of valid values for
 524 <var>langN</var> you can issue the following command in the
 525 <span class="file">gcc</span> directory of your GCC source tree:<br>
 526      <pre class="smallexample">          grep language= */config-lang.in
 527      </pre>
 528      <p>Currently, you can use any of the following:
 529 <code>ada</code>, <code>c</code>, <code>c++</code>, <code>f77</code>, <code>java</code>, <code>objc</code>.
 530 Building the Ada compiler has special requirements, see below.<br>
 531 If you do not pass this flag, all languages available in the <span class="file">gcc</span>
 532 sub-tree will be configured.  Re-defining <code>LANGUAGES</code> when calling
 533 <span class="samp">make bootstrap</span> <strong>does not</strong> work anymore, as those
 534 language sub-directories might not have been configured!
 535
 536      <br><dt><code>--with-dwarf2</code><dd>Specify that the compiler should
 537 use DWARF 2 debugging information as the default.
 538
 539      <br><dt><code>--enable-win32-registry</code><dt><code>--enable-win32-registry=</code><var>key</var><dt><code>--disable-win32-registry</code><dd>The <span class="option">--enable-win32-registry</span> option enables Microsoft Windows-hosted GCC
 540 to look up installations paths in the registry using the following key:
 541
 542      <pre class="smallexample">          <code>HKEY_LOCAL_MACHINE\SOFTWARE\Free Software Foundation\</code><var>key</var>
 543      </pre>
 544      <p><var>key</var> defaults to GCC version number, and can be overridden by the
 545 <span class="option">--enable-win32-registry=</span><var>key</var> option. Vendors and distributors
 546 who use custom installers are encouraged to provide a different key,
 547 perhaps one comprised of vendor name and GCC version number, to
 548 avoid conflict with existing installations.  This feature is enabled
 549 by default, and can be disabled by <span class="option">--disable-win32-registry</span>
 550 option.  This option has no effect on the other hosts.
 551
 552      <br><dt><code>--nfp</code><dd>Specify that the machine does not have a floating point unit.  This
 553 option only applies to <span class="samp">m68k-sun-sunos</span><var>n</var>.  On any other
 554 system, <span class="option">--nfp</span> has no effect.
 555
 556      <br><dt><code>--enable-werror</code><dt><code>--disable-werror</code><dt><code>--enable-werror=yes</code><dt><code>--enable-werror=no</code><dd>When you specify this option, it controls whether certain files in the
 557 compiler are built with <span class="option">-Werror</span> in bootstrap stage2 and later.
 558 If you don't specify it, <span class="option">-Werror</span> is turned on for the main
 559 development trunk.  However it defaults to off for release branches and
 560 final releases.  The specific files which get <span class="option">-Werror</span> are
 561 controlled by the Makefiles.
 562
 563      <br><dt><code>--enable-checking</code><dt><code>--enable-checking=</code><var>list</var><dd>When you specify this option, the compiler is built to perform checking
 564 of tree node types when referencing fields of that node, and some other
 565 internal consistency checks.  This does not change the generated code,
 566 but adds error checking within the compiler.  This will slow down the
 567 compiler and may only work properly if you are building the compiler
 568 with GCC.  This is on by default when building from CVS or snapshots,
 569 but off for releases.  More control over the checks may be had by
 570 specifying <var>list</var>; the categories of checks available are
 571 <span class="samp">misc</span>, <span class="samp">tree</span>, <span class="samp">gc</span>, <span class="samp">rtl</span>, <span class="samp">rtlflag</span>,
 572 <span class="samp">fold</span>, <span class="samp">gcac</span> and <span class="samp">valgrind</span>.  The check <span class="samp">valgrind</span>
 573 requires the external <span class="command">valgrind</span> simulator, available from
 574 <a href="http://valgrind.kde.org/">http://valgrind.kde.org/</a>.  The default when <var>list</var> is
 575 not specified is <span class="samp">misc,tree,gc,rtlflag</span>; the checks <span class="samp">rtl</span>,
 576 <span class="samp">gcac</span> and <span class="samp">valgrind</span> are very expensive.
 577
 578      <br><dt><code>--enable-coverage</code><dt><code>--enable-coverage=</code><var>level</var><dd>With this option, the compiler is built to collect self coverage
 579 information, every time it is run. This is for internal development
 580 purposes, and only works when the compiler is being built with gcc. The
 581 <var>level</var> argument controls whether the compiler is built optimized or
 582 not, values are <span class="samp">opt</span> and <span class="samp">noopt</span>. For coverage analysis you
 583 want to disable optimization, for performance analysis you want to
 584 enable optimization. When coverage is enabled, the default level is
 585 without optimization.
 586
 587      <br><dt><code>--enable-gather-detailed-mem-stats</code><dd>When this option is specified more detailed information on memory
 588 allocation is gathered.  This information is printed when using
 589 <span class="option">-fmem-report</span>.
 590
 591      <br><dt><code>--enable-nls</code><dt><code>--disable-nls</code><dd>The <span class="option">--enable-nls</span> option enables Native Language Support (NLS),
 592 which lets GCC output diagnostics in languages other than American
 593 English.  Native Language Support is enabled by default if not doing a
 594 canadian cross build.  The <span class="option">--disable-nls</span> option disables NLS.
 595
 596      <br><dt><code>--with-included-gettext</code><dd>If NLS is enabled, the <span class="option">--with-included-gettext</span> option causes the build
 597 procedure to prefer its copy of GNU <span class="command">gettext</span>.
 598
 599      <br><dt><code>--with-catgets</code><dd>If NLS is enabled, and if the host lacks <code>gettext</code> but has the
 600 inferior <code>catgets</code> interface, the GCC build procedure normally
 601 ignores <code>catgets</code> and instead uses GCC's copy of the GNU
 602 <code>gettext</code> library.  The <span class="option">--with-catgets</span> option causes the
 603 build procedure to use the host's <code>catgets</code> in this situation.
 604
 605      <br><dt><code>--with-libiconv-prefix=</code><var>dir</var><dd>Search for libiconv header files in <var>dir</var><span class="file">/include</span> and
 606 libiconv library files in <var>dir</var><span class="file">/lib</span>.
 607
 608      <br><dt><code>--enable-obsolete</code><dd>Enable configuration for an obsoleted system.  If you attempt to
 609 configure GCC for a system (build, host, or target) which has been
 610 obsoleted, and you do not specify this flag, configure will halt with an
 611 error message.
 612
 613      <p>All support for systems which have been obsoleted in one release of GCC
 614 is removed entirely in the next major release, unless someone steps
 615 forward to maintain the port.
 616 </dl>
 617
 618 <h4 class="subheading"><a name="TOC2"></a>Cross-Compiler-Specific Options</h4>
 619
 620 <p>The following options only apply to building cross compilers.
 621      <dl>
 622 <dt><code>--with-sysroot</code><dt><code>--with-sysroot=</code><var>dir</var><dd>Tells GCC to consider <var>dir</var> as the root of a tree that contains a
 623 (subset of) the root filesystem of the target operating system.
 624 Target system headers, libraries and run-time object files will be
 625 searched in there.  The specified directory is not copied into the
 626 install tree, unlike the options <span class="option">--with-headers</span> and
 627 <span class="option">--with-libs</span> that this option obsoletes.  The default value,
 628 in case <span class="option">--with-sysroot</span> is not given an argument, is
 629 <span class="option">${gcc_tooldir}/sys-root</span>.  If the specified directory is a
 630 subdirectory of <span class="option">${exec_prefix}</span>, then it will be found relative to
 631 the GCC binaries if the installation tree is moved.
 632
 633      <br><dt><code>--with-headers</code><dt><code>--with-headers=</code><var>dir</var><dd>Deprecated in favor of <span class="option">--with-sysroot</span>.
 634 Specifies that target headers are available when building a cross compiler.
 635 The <var>dir</var> argument specifies a directory which has the target include
 636 files.  These include files will be copied into the <span class="file">gcc</span> install
 637 directory.  <em>This option with the </em><var>dir</var><em> argument is required</em> when
 638 building a cross compiler, if <var>prefix</var><span class="file">/</span><var>target</var><span class="file">/sys-include</span>
 639 doesn't pre-exist.  If <var>prefix</var><span class="file">/</span><var>target</var><span class="file">/sys-include</span> does
 640 pre-exist, the <var>dir</var> argument may be omitted.  <span class="command">fixincludes</span>
 641 will be run on these files to make them compatible with GCC.
 642
 643      <br><dt><code>--without-headers</code><dd>Tells GCC not use any target headers from a libc when building a cross
 644 compiler.  When crossing to GNU/Linux, you need the headers so GCC
 645 can build the exception handling for libgcc.
 646 See <a href="http://www.objsw.com/CrossGCC/">CrossGCC</a> for more information
 647 on this option.
 648
 649      <br><dt><code>--with-libs</code><dt><code>--with-libs=``</code><var>dir1</var> <var>dir2</var><code> ... </code><var>dirN</var><code>''</code><dd>Deprecated in favor of <span class="option">--with-sysroot</span>.
 650 Specifies a list of directories which contain the target runtime
 651 libraries.  These libraries will be copied into the <span class="file">gcc</span> install
 652 directory.  If the directory list is omitted, this option has no
 653 effect.
 654 <br><dt><code>--with-newlib</code><dd>Specifies that <span class="samp">newlib</span> is
 655 being used as the target C library.  This causes <code>__eprintf</code> to be
 656 omitted from <span class="file">libgcc.a</span> on the assumption that it will be provided by
 657 <span class="samp">newlib</span>.
 658 </dl>
 659
 660 <h4 class="subheading"><a name="TOC3"></a>Java-Specific Options</h4>
 661
 662 <p>The following option applies to the build of the Java front end.
 663
 664      <dl>
 665 <dt><code>--disable-libgcj</code><dd>Specify that the run-time libraries
 666 used by GCJ should not be built.  This is useful in case you intend
 667 to use GCJ with some other run-time, or you're going to install it
 668 separately, or it just happens not to build on your particular
 669 machine.  In general, if the Java front end is enabled, the GCJ
 670 libraries will be enabled too, unless they're known to not work on
 671 the target platform.  If GCJ is enabled but <span class="samp">libgcj</span> isn't built, you
 672 may need to port it; in this case, before modifying the top-level
 673 <span class="file">configure.in</span> so that <span class="samp">libgcj</span> is enabled by default on this platform,
 674 you may use <span class="option">--enable-libgcj</span> to override the default.
 675
 676    </dl>
 677
 678    <p>The following options apply to building <span class="samp">libgcj</span>.
 679
 680 <h5 class="subsubheading"><a name="TOC4"></a>General Options</h5>
 681
 682      <dl>
 683 <dt><code>--disable-getenv-properties</code><dd>Don't set system properties from <span class="env">GCJ_PROPERTIES</span>.
 684
 685      <br><dt><code>--enable-hash-synchronization</code><dd>Use a global hash table for monitor locks. Ordinarily,
 686 <span class="samp">libgcj</span>'s <span class="samp">configure</span> script automatically makes
 687 the correct choice for this option for your platform. Only use
 688 this if you know you need the library to be configured differently.
 689
 690      <br><dt><code>--enable-interpreter</code><dd>Enable the Java interpreter. The interpreter is automatically
 691 enabled by default on all platforms that support it. This option
 692 is really only useful if you want to disable the interpreter
 693 (using <span class="option">--disable-interpreter</span>).
 694
 695      <br><dt><code>--disable-java-net</code><dd>Disable java.net. This disables the native part of java.net only,
 696 using non-functional stubs for native method implementations.
 697
 698      <br><dt><code>--disable-jvmpi</code><dd>Disable JVMPI support.
 699
 700      <br><dt><code>--with-ecos</code><dd>Enable runtime eCos target support.
 701
 702      <br><dt><code>--without-libffi</code><dd>Don't use <span class="samp">libffi</span>. This will disable the interpreter and JNI
 703 support as well, as these require <span class="samp">libffi</span> to work.
 704
 705      <br><dt><code>--enable-libgcj-debug</code><dd>Enable runtime debugging code.
 706
 707      <br><dt><code>--enable-libgcj-multifile</code><dd>If specified, causes all <span class="file">.java</span> source files to be
 708 compiled into <span class="file">.class</span> files in one invocation of
 709 <span class="samp">gcj</span>. This can speed up build time, but is more
 710 resource-intensive. If this option is unspecified or
 711 disabled, <span class="samp">gcj</span> is invoked once for each <span class="file">.java</span>
 712 file to compile into a <span class="file">.class</span> file.
 713
 714      <br><dt><code>--with-libiconv-prefix=DIR</code><dd>Search for libiconv in <span class="file">DIR/include</span> and <span class="file">DIR/lib</span>.
 715
 716      <br><dt><code>--enable-sjlj-exceptions</code><dd>Force use of <code>builtin_setjmp</code> for exceptions. <span class="samp">configure</span>
 717 ordinarily picks the correct value based on the platform. Only use
 718 this option if you are sure you need a different setting.
 719
 720      <br><dt><code>--with-system-zlib</code><dd>Use installed <span class="samp">zlib</span> rather than that included with GCC.
 721
 722      <br><dt><code>--with-win32-nlsapi=ansi, unicows or unicode</code><dd>Indicates how MinGW <span class="samp">libgcj</span> translates between UNICODE
 723 characters and the Win32 API.
 724           <dl>
 725 <dt><code>ansi</code><dd>Use the single-byte <code>char</code> and the Win32 A functions natively,
 726 translating to and from UNICODE when using these functions. If
 727 unspecified, this is the default.
 728
 729           <br><dt><code>unicows</code><dd>Use the <code>WCHAR</code> and Win32 W functions natively. Adds
 730 <code>-lunicows</code> to <span class="file">libgcj.spec</span> to link with <span class="samp">libunicows</span>.
 731 <span class="file">unicows.dll</span> needs to be deployed on Microsoft Windows 9X machines
 732 running built executables. <span class="file">libunicows.a</span>, an open-source
 733 import library around Microsoft's <code>unicows.dll</code>, is obtained from
 734 <a href="http://libunicows.sourceforge.net/">http://libunicows.sourceforge.net/</a>, which also gives details
 735 on getting <span class="file">unicows.dll</span> from Microsoft.
 736
 737           <br><dt><code>unicode</code><dd>Use the <code>WCHAR</code> and Win32 W functions natively. Does <em>not</em>
 738 add <code>-lunicows</code> to <span class="file">libgcj.spec</span>. The built executables will
 739 only run on Microsoft Windows NT and above.
 740 </dl>
 741      </dl>
 742
 743 <h5 class="subsubheading"><a name="TOC5"></a>AWT-Specific Options</h5>
 744
 745      <dl>
 746 <dt><code>--with-x</code><dd>Use the X Window System.
 747
 748      <br><dt><code>--enable-java-awt=PEER(S)</code><dd>Specifies the AWT peer library or libraries to build alongside
 749 <span class="samp">libgcj</span>. If this option is unspecified or disabled, AWT
 750 will be non-functional. Current valid values are <span class="option">gtk</span> and
 751 <span class="option">xlib</span>. Multiple libraries should be separated by a
 752 comma (i.e. <span class="option">--enable-java-awt=gtk,xlib</span>).
 753
 754      <br><dt><code>--enable-gtk-cairo</code><dd>Build the cairo Graphics2D implementation on GTK.
 755
 756      <br><dt><code>--enable-java-gc=TYPE</code><dd>Choose garbage collector. Defaults to <span class="option">boehm</span> if unspecified.
 757
 758      <br><dt><code>--disable-gtktest</code><dd>Do not try to compile and run a test GTK+ program.
 759
 760      <br><dt><code>--disable-glibtest</code><dd>Do not try to compile and run a test GLIB program.
 761
 762      <br><dt><code>--with-libart-prefix=PFX</code><dd>Prefix where libart is installed (optional).
 763
 764      <br><dt><code>--with-libart-exec-prefix=PFX</code><dd>Exec prefix where libart is installed (optional).
 765
 766      <br><dt><code>--disable-libarttest</code><dd>Do not try to compile and run a test libart program.
 767
 768 </dl>
 769
 770    <p><hr />
 771 <p><a href="./index.html">Return to the GCC Installation page</a>
 772
 773 <!-- ***Building**************************************************************** -->
 774 <!-- ***Testing***************************************************************** -->
 775 <!-- ***Final install*********************************************************** -->
 776 <!-- ***Binaries**************************************************************** -->
 777 <!-- ***Specific**************************************************************** -->
 778 <!-- ***Old documentation****************************************************** -->
 779 <!-- ***GFDL******************************************************************** -->
 780 <!-- *************************************************************************** -->
 781 <!-- Part 6 The End of the Document -->
 782 </body></html>
 783