1 This file documents the installation of the GNU compiler. Copyright
2 (C) 1988, 1989, 1992, 1994, 1995 Free Software Foundation, Inc. You
3 may copy, distribute, and modify it freely as long as you preserve this
4 copyright notice and permission notice.
9 Here is the procedure for installing GNU CC on a Unix system. See
10 *Note VMS Install::, for VMS systems. In this section we assume you
11 compile in the same directory that contains the source files; see *Note
12 Other Dir::, to find out how to compile in a separate directory on Unix
15 You cannot install GNU C by itself on MSDOS; it will not compile
16 under any MSDOS compiler except itself. You need to get the complete
17 compilation package DJGPP, which includes binaries as well as sources,
18 and includes all the necessary compilation tools and libraries.
20 1. If you have built GNU CC previously in the same directory for a
21 different target machine, do `make distclean' to delete all files
22 that might be invalid. One of the files this deletes is
23 `Makefile'; if `make distclean' complains that `Makefile' does not
24 exist, it probably means that the directory is already suitably
27 2. On a System V release 4 system, make sure `/usr/bin' precedes
28 `/usr/ucb' in `PATH'. The `cc' command in `/usr/ucb' uses
29 libraries which have bugs.
31 3. Specify the host, build and target machine configurations. You do
32 this by running the file `configure'.
34 The "build" machine is the system which you are using, the "host"
35 machine is the system where you want to run the resulting compiler
36 (normally the build machine), and the "target" machine is the
37 system for which you want the compiler to generate code.
39 If you are building a compiler to produce code for the machine it
40 runs on (a native compiler), you normally do not need to specify
41 any operands to `configure'; it will try to guess the type of
42 machine you are on and use that as the build, host and target
43 machines. So you don't need to specify a configuration when
44 building a native compiler unless `configure' cannot figure out
45 what your configuration is or guesses wrong.
47 In those cases, specify the build machine's "configuration name"
48 with the `--build' option; the host and target will default to be
49 the same as the build machine. (If you are building a
50 cross-compiler, see *Note Cross-Compiler::.)
54 ./configure --build=sparc-sun-sunos4.1
56 A configuration name may be canonical or it may be more or less
59 A canonical configuration name has three parts, separated by
60 dashes. It looks like this: `CPU-COMPANY-SYSTEM'. (The three
61 parts may themselves contain dashes; `configure' can figure out
62 which dashes serve which purpose.) For example,
63 `m68k-sun-sunos4.1' specifies a Sun 3.
65 You can also replace parts of the configuration by nicknames or
66 aliases. For example, `sun3' stands for `m68k-sun', so
67 `sun3-sunos4.1' is another way to specify a Sun 3. You can also
68 use simply `sun3-sunos', since the version of SunOS is assumed by
69 default to be version 4.
71 You can specify a version number after any of the system types,
72 and some of the CPU types. In most cases, the version is
73 irrelevant, and will be ignored. So you might as well specify the
74 version if you know it.
76 See *Note Configurations::, for a list of supported configuration
77 names and notes on many of the configurations. You should check
78 the notes in that section before proceeding any further with the
79 installation of GNU CC.
81 There are four additional options you can specify independently to
82 describe variant hardware and software configurations. These are
83 `--with-gnu-as', `--with-gnu-ld', `--with-stabs' and `--nfp'.
86 If you will use GNU CC with the GNU assembler (GAS), you
87 should declare this by using the `--with-gnu-as' option when
90 Using this option does not install GAS. It only modifies the
91 output of GNU CC to work with GAS. Building and installing
94 Conversely, if you *do not* wish to use GAS and do not specify
95 `--with-gnu-as' when building GNU CC, it is up to you to make
96 sure that GAS is not installed. GNU CC searches for a
97 program named `as' in various directories; if the program it
98 finds is GAS, then it runs GAS. If you are not sure where
99 GNU CC finds the assembler it is using, try specifying `-v'
102 The systems where it makes a difference whether you use GAS
104 `hppa1.0-ANY-ANY', `hppa1.1-ANY-ANY', `i386-ANY-sysv',
106 `i860-ANY-bsd', `m68k-bull-sysv',
107 `m68k-hp-hpux', `m68k-sony-bsd',
108 `m68k-altos-sysv', `m68000-hp-hpux',
109 `m68000-att-sysv', `ANY-lynx-lynxos', and `mips-ANY'). On
110 any other system, `--with-gnu-as' has no effect.
112 On the systems listed above (except for the HP-PA, for ISC on
113 the 386, and for `mips-sgi-irix5.*'), if you use GAS, you
114 should also use the GNU linker (and specify `--with-gnu-ld').
117 Specify the option `--with-gnu-ld' if you plan to use the GNU
120 This option does not cause the GNU linker to be installed; it
121 just modifies the behavior of GNU CC to work with the GNU
122 linker. Specifically, it inhibits the installation of
123 `collect2', a program which otherwise serves as a front-end
124 for the system's linker on most configurations.
127 On MIPS based systems and on Alphas, you must specify whether
128 you want GNU CC to create the normal ECOFF debugging format,
129 or to use BSD-style stabs passed through the ECOFF symbol
130 table. The normal ECOFF debug format cannot fully handle
131 languages other than C. BSD stabs format can handle other
132 languages, but it only works with the GNU debugger GDB.
134 Normally, GNU CC uses the ECOFF debugging format by default;
135 if you prefer BSD stabs, specify `--with-stabs' when you
138 No matter which default you choose when you configure GNU CC,
139 the user can use the `-gcoff' and `-gstabs+' options to
140 specify explicitly the debug format for a particular
143 `--with-stabs' is meaningful on the ISC system on the 386,
144 also, if `--with-gas' is used. It selects use of stabs
145 debugging information embedded in COFF output. This kind of
146 debugging information supports C++ well; ordinary COFF
147 debugging information does not.
149 `--with-stabs' is also meaningful on 386 systems running
150 SVR4. It selects use of stabs debugging information embedded
151 in ELF output. The C++ compiler currently (2.6.0) does not
152 support the DWARF debugging information normally used on 386
153 SVR4 platforms; stabs provide a workable alternative. This
154 requires gas and gdb, as the normal SVR4 tools can not
155 generate or interpret stabs.
158 On certain systems, you must specify whether the machine has
159 a floating point unit. These systems include
160 `m68k-sun-sunosN' and `m68k-isi-bsd'. On any other system,
161 `--nfp' currently has no effect, though perhaps there are
162 other systems where it could usefully make a difference.
164 `--enable-objcthreads=TYPE'
165 Certain systems, notably Linux-based GNU systems, can't be
166 relied on to supply a threads facility for the Objective C
167 runtime and so will default to single-threaded runtime. They
168 may, however, have a library threads implementation
169 available, in which case threads can be enabled with this
170 option by supplying a suitable TYPE, probably `posix'. The
171 possibilities for TYPE are `single', `posix', `win32',
172 `solaris', `irix' and `mach'.
174 The `configure' script searches subdirectories of the source
175 directory for other compilers that are to be integrated into GNU
176 CC. The GNU compiler for C++, called G++ is in a subdirectory
177 named `cp'. `configure' inserts rules into `Makefile' to build
178 all of those compilers.
180 Here we spell out what files will be set up by `configure'.
181 Normally you need not be concerned with these files.
183 * A file named `config.h' is created that contains a `#include'
184 of the top-level config file for the machine you will run the
185 compiler on (*note The Configuration File:
186 (gcc.info)Config.). This file is responsible for defining
187 information about the host machine. It includes `tm.h'.
189 The top-level config file is located in the subdirectory
190 `config'. Its name is always `xm-SOMETHING.h'; usually
191 `xm-MACHINE.h', but there are some exceptions.
193 If your system does not support symbolic links, you might
194 want to set up `config.h' to contain a `#include' command
195 which refers to the appropriate file.
197 * A file named `tconfig.h' is created which includes the
198 top-level config file for your target machine. This is used
199 for compiling certain programs to run on that machine.
201 * A file named `tm.h' is created which includes the
202 machine-description macro file for your target machine. It
203 should be in the subdirectory `config' and its name is often
206 * The command file `configure' also constructs the file
207 `Makefile' by adding some text to the template file
208 `Makefile.in'. The additional text comes from files in the
209 `config' directory, named `t-TARGET' and `x-HOST'. If these
210 files do not exist, it means nothing needs to be added for a
211 given target or host.
213 4. The standard directory for installing GNU CC is `/usr/local/lib'.
214 If you want to install its files somewhere else, specify
215 `--prefix=DIR' when you run `configure'. Here DIR is a directory
216 name to use instead of `/usr/local' for all purposes with one
217 exception: the directory `/usr/local/include' is searched for
218 header files no matter where you install the compiler. To override
219 this name, use the `--local-prefix' option below.
221 5. Specify `--local-prefix=DIR' if you want the compiler to search
222 directory `DIR/include' for locally installed header files
223 *instead* of `/usr/local/include'.
225 You should specify `--local-prefix' *only* if your site has a
226 different convention (not `/usr/local') for where to put
229 The default value for `--local-prefix' is `/usr/local' regardless
230 of the value of `--prefix'. Specifying `--prefix' has no effect
231 on which directory GNU CC searches for local header files. This
232 may seem counterintuitive, but actually it is logical.
234 The purpose of `--prefix' is to specify where to *install GNU CC*.
235 The local header files in `/usr/local/include'--if you put any in
236 that directory--are not part of GNU CC. They are part of other
237 programs--perhaps many others. (GNU CC installs its own header
238 files in another directory which is based on the `--prefix' value.)
240 *Do not* specify `/usr' as the `--local-prefix'! The directory
241 you use for `--local-prefix' *must not* contain any of the
242 system's standard header files. If it did contain them, certain
243 programs would be miscompiled (including GNU Emacs, on certain
244 targets), because this would override and nullify the header file
245 corrections made by the `fixincludes' script.
247 Indications are that people who use this option use it based on
248 mistaken ideas of what it is for. People use it as if it specified
249 where to install part of GNU CC. Perhaps they make this assumption
250 because installing GNU CC creates the directory.
252 6. Make sure the Bison parser generator is installed. (This is
253 unnecessary if the Bison output files `c-parse.c' and `cexp.c' are
254 more recent than `c-parse.y' and `cexp.y' and you do not plan to
255 change the `.y' files.)
257 Bison versions older than Sept 8, 1988 will produce incorrect
258 output for `c-parse.c'.
260 7. If you have chosen a configuration for GNU CC which requires other
261 GNU tools (such as GAS or the GNU linker) instead of the standard
262 system tools, install the required tools in the build directory
263 under the names `as', `ld' or whatever is appropriate. This will
264 enable the compiler to find the proper tools for compilation of
265 the program `enquire'.
267 Alternatively, you can do subsequent compilation using a value of
268 the `PATH' environment variable such that the necessary GNU tools
269 come before the standard system tools.
271 8. Build the compiler. Just type `make LANGUAGES=c' in the compiler
274 `LANGUAGES=c' specifies that only the C compiler should be
275 compiled. The makefile normally builds compilers for all the
276 supported languages; currently, C, C++ and Objective C. However,
277 C is the only language that is sure to work when you build with
278 other non-GNU C compilers. In addition, building anything but C
279 at this stage is a waste of time.
281 In general, you can specify the languages to build by typing the
282 argument `LANGUAGES="LIST"', where LIST is one or more words from
283 the list `c', `c++', and `objective-c'. If you have any
284 additional GNU compilers as subdirectories of the GNU CC source
285 directory, you may also specify their names in this list.
287 Ignore any warnings you may see about "statement not reached" in
288 `insn-emit.c'; they are normal. Also, warnings about "unknown
289 escape sequence" are normal in `genopinit.c' and perhaps some
290 other files. Likewise, you should ignore warnings about "constant
291 is so large that it is unsigned" in `insn-emit.c' and
292 `insn-recog.c' and a warning about a comparison always being zero
293 in `enquire.o'. Any other compilation errors may represent bugs in
294 the port to your machine or operating system, and should be
295 investigated and reported.
297 Some commercial compilers fail to compile GNU CC because they have
298 bugs or limitations. For example, the Microsoft compiler is said
299 to run out of macro space. Some Ultrix compilers run out of
300 expression space; then you need to break up the statement where
303 9. If you are building a cross-compiler, stop here. *Note
306 10. Move the first-stage object files and executables into a
307 subdirectory with this command:
311 The files are moved into a subdirectory named `stage1'. Once
312 installation is complete, you may wish to delete these files with
315 11. If you have chosen a configuration for GNU CC which requires other
316 GNU tools (such as GAS or the GNU linker) instead of the standard
317 system tools, install the required tools in the `stage1'
318 subdirectory under the names `as', `ld' or whatever is
319 appropriate. This will enable the stage 1 compiler to find the
320 proper tools in the following stage.
322 Alternatively, you can do subsequent compilation using a value of
323 the `PATH' environment variable such that the necessary GNU tools
324 come before the standard system tools.
326 12. Recompile the compiler with itself, with this command:
328 make CC="stage1/xgcc -Bstage1/" CFLAGS="-g -O2"
330 This is called making the stage 2 compiler.
332 The command shown above builds compilers for all the supported
333 languages. If you don't want them all, you can specify the
334 languages to build by typing the argument `LANGUAGES="LIST"'. LIST
335 should contain one or more words from the list `c', `c++',
336 `objective-c', and `proto'. Separate the words with spaces.
337 `proto' stands for the programs `protoize' and `unprotoize'; they
338 are not a separate language, but you use `LANGUAGES' to enable or
339 disable their installation.
341 If you are going to build the stage 3 compiler, then you might
342 want to build only the C language in stage 2.
344 Once you have built the stage 2 compiler, if you are short of disk
345 space, you can delete the subdirectory `stage1'.
347 On a 68000 or 68020 system lacking floating point hardware, unless
348 you have selected a `tm.h' file that expects by default that there
349 is no such hardware, do this instead:
351 make CC="stage1/xgcc -Bstage1/" CFLAGS="-g -O2 -msoft-float"
353 13. If you wish to test the compiler by compiling it with itself one
354 more time, install any other necessary GNU tools (such as GAS or
355 the GNU linker) in the `stage2' subdirectory as you did in the
356 `stage1' subdirectory, then do this:
359 make CC="stage2/xgcc -Bstage2/" CFLAGS="-g -O2"
361 This is called making the stage 3 compiler. Aside from the `-B'
362 option, the compiler options should be the same as when you made
363 the stage 2 compiler. But the `LANGUAGES' option need not be the
364 same. The command shown above builds compilers for all the
365 supported languages; if you don't want them all, you can specify
366 the languages to build by typing the argument `LANGUAGES="LIST"',
369 If you do not have to install any additional GNU tools, you may
372 make bootstrap LANGUAGES=LANGUAGE-LIST BOOT_CFLAGS=OPTION-LIST
374 instead of making `stage1', `stage2', and performing the two
377 14. Then compare the latest object files with the stage 2 object
378 files--they ought to be identical, aside from time stamps (if any).
380 On some systems, meaningful comparison of object files is
381 impossible; they always appear "different." This is currently
382 true on Solaris and some systems that use ELF object file format.
383 On some versions of Irix on SGI machines and DEC Unix (OSF/1) on
384 Alpha systems, you will not be able to compare the files without
385 specifying `-save-temps'; see the description of individual
386 systems above to see if you get comparison failures. You may have
387 similar problems on other systems.
389 Use this command to compare the files:
393 This will mention any object files that differ between stage 2 and
394 stage 3. Any difference, no matter how innocuous, indicates that
395 the stage 2 compiler has compiled GNU CC incorrectly, and is
396 therefore a potentially serious bug which you should investigate
399 If your system does not put time stamps in the object files, then
400 this is a faster way to compare them (using the Bourne shell):
403 cmp $file stage2/$file
406 If you have built the compiler with the `-mno-mips-tfile' option on
407 MIPS machines, you will not be able to compare the files.
409 15. Install the compiler driver, the compiler's passes and run-time
410 support with `make install'. Use the same value for `CC',
411 `CFLAGS' and `LANGUAGES' that you used when compiling the files
412 that are being installed. One reason this is necessary is that
413 some versions of Make have bugs and recompile files gratuitously
414 when you do this step. If you use the same variable values, those
415 files will be recompiled properly.
417 For example, if you have built the stage 2 compiler, you can use
418 the following command:
420 make install CC="stage2/xgcc -Bstage2/" CFLAGS="-g -O" LANGUAGES="LIST"
422 This copies the files `cc1', `cpp' and `libgcc.a' to files `cc1',
423 `cpp' and `libgcc.a' in the directory
424 `/usr/local/lib/gcc-lib/TARGET/VERSION', which is where the
425 compiler driver program looks for them. Here TARGET is the target
426 machine type specified when you ran `configure', and VERSION is
427 the version number of GNU CC. This naming scheme permits various
428 versions and/or cross-compilers to coexist. It also copies the
429 executables for compilers for other languages (e.g., `cc1plus' for
430 C++) to the same directory.
432 This also copies the driver program `xgcc' into
433 `/usr/local/bin/gcc', so that it appears in typical execution
434 search paths. It also copies `gcc.1' into `/usr/local/man/man1'
435 and info pages into `/usr/local/info'.
437 On some systems, this command causes recompilation of some files.
438 This is usually due to bugs in `make'. You should either ignore
439 this problem, or use GNU Make.
441 *Warning: there is a bug in `alloca' in the Sun library. To avoid
442 this bug, be sure to install the executables of GNU CC that were
443 compiled by GNU CC. (That is, the executables from stage 2 or 3,
444 not stage 1.) They use `alloca' as a built-in function and never
445 the one in the library.*
447 (It is usually better to install GNU CC executables from stage 2
448 or 3, since they usually run faster than the ones compiled with
449 some other compiler.)
451 16. If you're going to use C++, it's likely that you need to also
452 install the libg++ distribution. It should be available from the
453 same place where you got the GNU C distribution. Just as GNU C
454 does not distribute a C runtime library, it also does not include
455 a C++ run-time library. All I/O functionality, special class
456 libraries, etc., are available in the libg++ distribution.
458 17. GNU CC includes a runtime library for Objective-C because it is an
459 integral part of the language. You can find the files associated
460 with the library in the subdirectory `objc'. The GNU Objective-C
461 Runtime Library requires header files for the target's C library in
462 order to be compiled,and also requires the header files for the
463 target's thread library if you want thread support. *Note
464 Cross-Compilers and Header Files: Cross Headers, for discussion
465 about header files issues for cross-compilation.
467 When you run `configure', it picks the appropriate Objective-C
468 thread implementation file for the target platform. In some
469 situations, you may wish to choose a different back-end as some
470 platforms support multiple thread implementations or you may wish
471 to disable thread support completely. You do this by specifying a
472 value for the OBJC_THREAD_FILE makefile variable on the command
473 line when you run make, for example:
475 make CC="stage2/xgcc -Bstage2/" CFLAGS="-g -O2" OBJC_THREAD_FILE=thr-single
477 Below is a list of the currently available back-ends.
479 * thr-single Disable thread support, should work for all
482 * thr-decosf1 DEC OSF/1 thread support.
484 * thr-irix SGI IRIX thread support.
486 * thr-mach Generic MACH thread support, known to work on
489 * thr-os2 IBM OS/2 thread support.
491 * thr-posix Generix POSIX thread support.
493 * thr-pthreads PCThreads on Linux-based GNU systems.
495 * thr-solaris SUN Solaris thread support.
497 * thr-win32 Microsoft Win32 API thread support.
499 Configurations Supported by GNU CC
500 ==================================
502 Here are the possible CPU types:
504 1750a, a29k, alpha, arm, cN, clipper, dsp16xx, elxsi, h8300,
505 hppa1.0, hppa1.1, i370, i386, i486, i586, i860, i960, m32r,
506 m68000, m68k, m88k, mips, mipsel, mips64, mips64el, ns32k,
507 powerpc, powerpcle, pyramid, romp, rs6000, sh, sparc, sparclite,
510 Here are the recognized company names. As you can see, customary
511 abbreviations are used rather than the longer official names.
513 acorn, alliant, altos, apollo, apple, att, bull, cbm, convergent,
514 convex, crds, dec, dg, dolphin, elxsi, encore, harris, hitachi,
515 hp, ibm, intergraph, isi, mips, motorola, ncr, next, ns, omron,
516 plexus, sequent, sgi, sony, sun, tti, unicom, wrs.
518 The company name is meaningful only to disambiguate when the rest of
519 the information supplied is insufficient. You can omit it, writing
520 just `CPU-SYSTEM', if it is not needed. For example, `vax-ultrix4.2'
521 is equivalent to `vax-dec-ultrix4.2'.
523 Here is a list of system types:
525 386bsd, aix, acis, amigaos, aos, aout, aux, bosx, bsd, clix, coff,
526 ctix, cxux, dgux, dynix, ebmon, ecoff, elf, esix, freebsd, hms,
527 genix, gnu, linux-gnu, hiux, hpux, iris, irix, isc, luna, lynxos,
528 mach, minix, msdos, mvs, netbsd, newsos, nindy, ns, osf, osfrose,
529 ptx, riscix, riscos, rtu, sco, sim, solaris, sunos, sym, sysv,
530 udi, ultrix, unicos, uniplus, unos, vms, vsta, vxworks, winnt,
533 You can omit the system type; then `configure' guesses the operating
534 system from the CPU and company.
536 You can add a version number to the system type; this may or may not
537 make a difference. For example, you can write `bsd4.3' or `bsd4.4' to
538 distinguish versions of BSD. In practice, the version number is most
539 needed for `sysv3' and `sysv4', which are often treated differently.
541 If you specify an impossible combination such as `i860-dg-vms', then
542 you may get an error message from `configure', or it may ignore part of
543 the information and do the best it can with the rest. `configure'
544 always prints the canonical name for the alternative that it used. GNU
545 CC does not support all possible alternatives.
547 Often a particular model of machine has a name. Many machine names
548 are recognized as aliases for CPU/company combinations. Thus, the
549 machine name `sun3', mentioned above, is an alias for `m68k-sun'.
550 Sometimes we accept a company name as a machine name, when the name is
551 popularly used for a particular machine. Here is a table of the known
554 3300, 3b1, 3bN, 7300, altos3068, altos, apollo68, att-7300,
555 balance, convex-cN, crds, decstation-3100, decstation, delta,
556 encore, fx2800, gmicro, hp7NN, hp8NN, hp9k2NN, hp9k3NN, hp9k7NN,
557 hp9k8NN, iris4d, iris, isi68, m3230, magnum, merlin, miniframe,
558 mmax, news-3600, news800, news, next, pbd, pc532, pmax, powerpc,
559 powerpcle, ps2, risc-news, rtpc, sun2, sun386i, sun386, sun3,
560 sun4, symmetry, tower-32, tower.
562 Remember that a machine name specifies both the cpu type and the company
563 name. If you want to install your own homemade configuration files,
564 you can use `local' as the company name to access them. If you use
565 configuration `CPU-local', the configuration name without the cpu prefix
566 is used to form the configuration file names.
568 Thus, if you specify `m68k-local', configuration uses files
569 `m68k.md', `local.h', `m68k.c', `xm-local.h', `t-local', and `x-local',
570 all in the directory `config/m68k'.
572 Here is a list of configurations that have special treatment or
573 special things you must know:
576 MIL-STD-1750A processors.
578 The MIL-STD-1750A cross configuration produces output for
579 `as1750', an assembler/linker available under the GNU Public
580 License for the 1750A. `as1750' can be obtained at
581 *ftp://ftp.fta-berlin.de/pub/crossgcc/1750gals/*. A similarly
582 licensed simulator for the 1750A is available from same address.
584 You should ignore a fatal error during the building of libgcc
585 (libgcc is not yet implemented for the 1750A.)
587 The `as1750' assembler requires the file `ms1750.inc', which is
588 found in the directory `config/1750a'.
590 GNU CC produced the same sections as the Fairchild F9450 C
594 The program code section.
597 The read/write (RAM) data section.
600 The read-only (ROM) constants section.
603 Initialization section (code to copy KREL to SREL).
605 The smallest addressable unit is 16 bits (BITS_PER_UNIT is 16).
606 This means that type `char' is represented with a 16-bit word per
607 character. The 1750A's "Load/Store Upper/Lower Byte" instructions
608 are not used by GNU CC.
611 Systems using processors that implement the DEC Alpha architecture
612 and are running the DEC Unix (OSF/1) operating system, for example
613 the DEC Alpha AXP systems.CC.)
615 GNU CC writes a `.verstamp' directive to the assembler output file
616 unless it is built as a cross-compiler. It gets the version to
617 use from the system header file `/usr/include/stamp.h'. If you
618 install a new version of DEC Unix, you should rebuild GCC to pick
619 up the new version stamp.
621 Note that since the Alpha is a 64-bit architecture,
622 cross-compilers from 32-bit machines will not generate code as
623 efficient as that generated when the compiler is running on a
624 64-bit machine because many optimizations that depend on being
625 able to represent a word on the target in an integral value on the
626 host cannot be performed. Building cross-compilers on the Alpha
627 for 32-bit machines has only been tested in a few cases and may
630 `make compare' may fail on old versions of DEC Unix unless you add
631 `-save-temps' to `CFLAGS'. On these systems, the name of the
632 assembler input file is stored in the object file, and that makes
633 comparison fail if it differs between the `stage1' and `stage2'
634 compilations. The option `-save-temps' forces a fixed name to be
635 used for the assembler input file, instead of a randomly chosen
636 name in `/tmp'. Do not add `-save-temps' unless the comparisons
637 fail without that option. If you add `-save-temps', you will have
638 to manually delete the `.i' and `.s' files after each series of
641 GNU CC now supports both the native (ECOFF) debugging format used
642 by DBX and GDB and an encapsulated STABS format for use only with
643 GDB. See the discussion of the `--with-stabs' option of
644 `configure' above for more information on these formats and how to
647 There is a bug in DEC's assembler that produces incorrect line
648 numbers for ECOFF format when the `.align' directive is used. To
649 work around this problem, GNU CC will not emit such alignment
650 directives while writing ECOFF format debugging information even
651 if optimization is being performed. Unfortunately, this has the
652 very undesirable side-effect that code addresses when `-O' is
653 specified are different depending on whether or not `-g' is also
656 To avoid this behavior, specify `-gstabs+' and use GDB instead of
657 DBX. DEC is now aware of this problem with the assembler and
658 hopes to provide a fix shortly.
661 Argonaut ARC processor. This configuration is intended for
665 Advanced RISC Machines ARM-family processors. These are often
666 used in embedded applications. There are no standard Unix
667 configurations. This configuration corresponds to the basic
668 instruction sequences and will produce `a.out' format object
671 You may need to make a variant of the file `arm.h' for your
672 particular configuration.
675 Any of the ARM family processors running the Linux-based GNU
676 system with the `a.out' binary format (ELF is not yet supported).
677 You must use version 2.8.1.0.7 or later of the GNU/Linux binutils,
678 which you can download from `sunsite.unc.edu:/pub/Linux/GCC' and
679 other mirror sites for Linux-based GNU systems.
682 The ARM2 or ARM3 processor running RISC iX, Acorn's port of BSD
683 Unix. If you are running a version of RISC iX prior to 1.2 then
684 you must specify the version number during configuration. Note
685 that the assembler shipped with RISC iX does not support stabs
686 debugging information; a new version of the assembler, with stabs
687 support included, is now available from Acorn.
690 AMD Am29k-family processors. These are normally used in embedded
691 applications. There are no standard Unix configurations. This
692 configuration corresponds to AMD's standard calling sequence and
693 binary interface and is compatible with other 29k tools.
695 You may need to make a variant of the file `a29k.h' for your
696 particular configuration.
699 AMD Am29050 used in a system running a variant of BSD Unix.
702 DECstations can support three different personalities: Ultrix, DEC
703 OSF/1, and OSF/rose. To configure GCC for these platforms use the
704 following configurations:
707 Ultrix configuration.
710 Dec's version of OSF/1.
713 Open Software Foundation reference port of OSF/1 which uses
714 the OSF/rose object file format instead of ECOFF. Normally,
715 you would not select this configuration.
717 The MIPS C compiler needs to be told to increase its table size
718 for switch statements with the `-Wf,-XNg1500' option in order to
719 compile `cp/parse.c'. If you use the `-O2' optimization option,
720 you also need to use `-Olimit 3000'. Both of these options are
721 automatically generated in the `Makefile' that the shell script
722 `configure' builds. If you override the `CC' make variable and
723 use the MIPS compilers, you may need to add `-Wf,-XNg1500 -Olimit
727 The Elxsi's C compiler has known limitations that prevent it from
728 compiling GNU C. Please contact `mrs@cygnus.com' for more details.
731 A port to the AT&T DSP1610 family of processors.
734 Hitachi H8/300 series of processors.
736 The calling convention and structure layout has changed in release
737 2.6. All code must be recompiled. The calling convention now
738 passes the first three arguments in function calls in registers.
739 Structures are no longer a multiple of 2 bytes.
742 There are several variants of the HP-PA processor which run a
743 variety of operating systems. GNU CC must be configured to use
744 the correct processor type and operating system, or GNU CC will
745 not function correctly. The easiest way to handle this problem is
746 to *not* specify a target when configuring GNU CC, the `configure'
747 script will try to automatically determine the right processor
748 type and operating system.
750 `-g' does not work on HP-UX, since that system uses a peculiar
751 debugging format which GNU CC does not know about. However, `-g'
752 will work if you also use GAS and GDB in conjunction with GCC. We
753 highly recommend using GAS for all HP-PA configurations.
755 You should be using GAS-2.6 (or later) along with GDB-4.16 (or
756 later). These can be retrieved from all the traditional GNU ftp
759 GAS will need to be installed into a directory before `/bin',
760 `/usr/bin', and `/usr/ccs/bin' in your search path. You should
761 install GAS before you build GNU CC.
763 To enable debugging, you must configure GNU CC with the
764 `--with-gnu-as' option before building.
767 This port is very preliminary and has many known bugs. We hope to
768 have a higher-quality port for this machine soon.
770 `i386-*-linux-gnuoldld'
771 Use this configuration to generate `a.out' binaries on Linux-based
772 GNU systems if you do not have gas/binutils version 2.5.2 or later
773 installed. This is an obsolete configuration.
775 `i386-*-linux-gnuaout'
776 Use this configuration to generate `a.out' binaries on Linux-based
777 GNU systems. This configuration is being superseded. You must use
778 gas/binutils version 2.5.2 or later.
781 Use this configuration to generate ELF binaries on Linux-based GNU
782 systems. You must use gas/binutils version 2.5.2 or later.
785 Compilation with RCC is recommended. Also, it may be a good idea
786 to link with GNU malloc instead of the malloc that comes with the
790 Use this configuration for SCO release 3.2 version 4.
793 Use this for the SCO OpenServer Release family including 5.0.0,
794 5.0.2, 5.0.4, Internet FastStart 1.0, and Internet FastStart 1.1.
796 GNU CC can generate ELF binaries (if you specify `-melf') or COFF
797 binaries (the default). If you are going to build your compiler
798 in ELF mode (once you have bootstrapped the first stage compiler)
799 you *must* specify `-melf' as part of `CC', *not* `CFLAGS', for
800 example as `CC="stage1/xgcc -melf -Bstage1/" '. If you do not do
801 this, the bootstrap will generate incorrect versions of `libgcc.a'.
803 You must have TLS597 (from ftp.sco.com/TLS) installed for ELF
804 binaries to work correctly. Note that Open Server 5.0.2 *does*
805 need TLS597 installed.
807 *NOTE:* You must follow the instructions about invoking `make
808 bootstrap' because the native OpenServer compiler builds a
809 `cc1plus' that will not correctly parse many valid C++ programs.
810 You must do a `make bootstrap' if you are building with the native
814 It may be a good idea to link with GNU malloc instead of the
815 malloc that comes with the system.
817 In ISC version 4.1, `sed' core dumps when building `deduced.h'.
818 Use the version of `sed' from version 4.0.
821 It may be good idea to link with GNU malloc instead of the malloc
822 that comes with the system.
825 You need to use GAS version 2.1 or later, and LD from GNU binutils
826 version 2.2 or later.
829 Go to the Berkeley universe before compiling.
832 Sequent DYNIX/ptx 1.x.
835 Sequent DYNIX/ptx 2.x.
838 You may find that you need another version of GNU CC to begin
839 bootstrapping with, since the current version when built with the
840 system's own compiler seems to get an infinite loop compiling part
841 of `libgcc2.c'. GNU CC version 2 compiled with GNU CC (any
842 version) seems not to have this problem.
844 See *Note Sun Install::, for information on installing GNU CC on
847 `i[345]86-*-winnt3.5'
848 This version requires a GAS that has not yet been released. Until
849 it is, you can get a prebuilt binary version via anonymous ftp from
850 `cs.washington.edu:pub/gnat' or `cs.nyu.edu:pub/gnat'. You must
851 also use the Microsoft header files from the Windows NT 3.5 SDK.
852 Find these on the CDROM in the `/mstools/h' directory dated
853 9/4/94. You must use a fixed version of Microsoft linker made
854 especially for NT 3.5, which is also is available on the NT 3.5
855 SDK CDROM. If you do not have this linker, can you also use the
856 linker from Visual C/C++ 1.0 or 2.0.
858 Installing GNU CC for NT builds a wrapper linker, called `ld.exe',
859 which mimics the behaviour of Unix `ld' in the specification of
860 libraries (`-L' and `-l'). `ld.exe' looks for both Unix and
861 Microsoft named libraries. For example, if you specify `-lfoo',
862 `ld.exe' will look first for `libfoo.a' and then for `foo.lib'.
864 You may install GNU CC for Windows NT in one of two ways,
865 depending on whether or not you have a Unix-like shell and various
868 1. If you do not have a Unix-like shell and few Unix-like
869 utilities, you will use a DOS style batch script called
870 `configure.bat'. Invoke it as `configure winnt' from an
871 MSDOS console window or from the program manager dialog box.
872 `configure.bat' assumes you have already installed and have
873 in your path a Unix-like `sed' program which is used to
874 create a working `Makefile' from `Makefile.in'.
876 `Makefile' uses the Microsoft Nmake program maintenance
877 utility and the Visual C/C++ V8.00 compiler to build GNU CC.
878 You need only have the utilities `sed' and `touch' to use
879 this installation method, which only automatically builds the
880 compiler itself. You must then examine what `fixinc.winnt'
881 does, edit the header files by hand and build `libgcc.a'
884 2. The second type of installation assumes you are running a
885 Unix-like shell, have a complete suite of Unix-like utilities
886 in your path, and have a previous version of GNU CC already
887 installed, either through building it via the above
888 installation method or acquiring a pre-built binary. In this
889 case, use the `configure' script in the normal fashion.
892 This is the Paragon. If you have version 1.0 of the operating
893 system, you need to take special steps to build GNU CC due to
894 peculiarities of the system. Newer system versions have no
895 problem. See the section `Installation Problems' in the GNU CC
899 LynxOS 2.2 and earlier comes with GNU CC 1.x already installed as
900 `/bin/gcc'. You should compile with this instead of `/bin/cc'.
901 You can tell GNU CC to use the GNU assembler and linker, by
902 specifying `--with-gnu-as --with-gnu-ld' when configuring. These
903 will produce COFF format object files and executables; otherwise
904 GNU CC will use the installed tools, which produce `a.out' format
908 Mitsubishi M32R processor. This configuration is intended for
912 HP 9000 series 200 running BSD. Note that the C compiler that
913 comes with this system cannot compile GNU CC; contact
914 `law@cs.utah.edu' to get binaries of GNU CC for bootstrapping.
917 Altos 3068. You must use the GNU assembler, linker and debugger.
918 Also, you must fix a kernel bug. Details in the file
922 Apple Macintosh running A/UX. You may configure GCC to use
923 either the system assembler and linker or the GNU assembler and
924 linker. You should use the GNU configuration if you can,
925 especially if you also want to use GNU C++. You enabled that
926 configuration with + the `--with-gnu-as' and `--with-gnu-ld'
927 options to `configure'.
929 Note the C compiler that comes with this system cannot compile GNU
930 CC. You can fine binaries of GNU CC for bootstrapping on
931 `jagubox.gsfc.nasa.gov'. You will also a patched version of
932 `/bin/ld' there that raises some of the arbitrary limits found in
936 AT&T 3b1, a.k.a. 7300 PC. Special procedures are needed to
937 compile GNU CC with this machine's standard C compiler, due to
938 bugs in that compiler. You can bootstrap it more easily with
939 previous versions of GNU CC if you have them.
941 Installing GNU CC on the 3b1 is difficult if you do not already
942 have GNU CC running, due to bugs in the installed C compiler.
943 However, the following procedure might work. We are unable to
946 1. Comment out the `#include "config.h"' line near the start of
947 `cccp.c' and do `make cpp'. This makes a preliminary version
950 2. Save the old `/lib/cpp' and copy the preliminary GNU cpp to
953 3. Undo your change in `cccp.c', or reinstall the original
954 version, and do `make cpp' again.
956 4. Copy this final version of GNU cpp into `/lib/cpp'.
958 5. Replace every occurrence of `obstack_free' in the file
959 `tree.c' with `_obstack_free'.
961 6. Run `make' to get the first-stage GNU CC.
963 7. Reinstall the original version of `/lib/cpp'.
965 8. Now you can compile GNU CC with itself and install it in the
969 Bull DPX/2 series 200 and 300 with BOS-2.00.45 up to BOS-2.01. GNU
970 CC works either with native assembler or GNU assembler. You can use
971 GNU assembler with native coff generation by providing
972 `--with-gnu-as' to the configure script or use GNU assembler with
973 dbx-in-coff encapsulation by providing `--with-gnu-as --stabs'.
974 For any problem with native assembler or for availability of the
975 DPX/2 port of GAS, contact `F.Pierresteguy@frcl.bull.fr'.
978 Use `configure unos' for building on Unos.
980 The Unos assembler is named `casm' instead of `as'. For some
981 strange reason linking `/bin/as' to `/bin/casm' changes the
982 behavior, and does not work. So, when installing GNU CC, you
983 should install the following script as `as' in the subdirectory
984 where the passes of GCC are installed:
989 The default Unos library is named `libunos.a' instead of `libc.a'.
990 To allow GNU CC to function, either change all references to
991 `-lc' in `gcc.c' to `-lunos' or link `/lib/libc.a' to
994 When compiling GNU CC with the standard compiler, to overcome bugs
995 in the support of `alloca', do not use `-O' when making stage 2.
996 Then use the stage 2 compiler with `-O' to make the stage 3
997 compiler. This compiler will have the same characteristics as the
998 usual stage 2 compiler on other systems. Use it to make a stage 4
999 compiler and compare that with stage 3 to verify proper
1002 (Perhaps simply defining `ALLOCA' in `x-crds' as described in the
1003 comments there will make the above paragraph superfluous. Please
1004 inform us of whether this works.)
1006 Unos uses memory segmentation instead of demand paging, so you
1007 will need a lot of memory. 5 Mb is barely enough if no other
1008 tasks are running. If linking `cc1' fails, try putting the object
1009 files into a library and linking from that library.
1012 HP 9000 series 300 or 400 running HP-UX. HP-UX version 8.0 has a
1013 bug in the assembler that prevents compilation of GNU CC. To fix
1014 it, get patch PHCO_4484 from HP.
1016 In addition, if you wish to use gas `--with-gnu-as' you must use
1017 gas version 2.1 or later, and you must use the GNU linker version
1018 2.1 or later. Earlier versions of gas relied upon a program which
1019 converted the gas output into the native HP/UX format, but that
1020 program has not been kept up to date. gdb does not understand
1021 that native HP/UX format, so you must use gas if you wish to use
1025 Sun 3. We do not provide a configuration file to use the Sun FPA
1026 by default, because programs that establish signal handlers for
1027 floating point traps inherently cannot work with the FPA.
1029 See *Note Sun Install::, for information on installing GNU CC on
1033 Motorola m88k running the AT&T/Unisoft/Motorola V.3 reference port.
1034 These systems tend to use the Green Hills C, revision 1.8.5, as the
1035 standard C compiler. There are apparently bugs in this compiler
1036 that result in object files differences between stage 2 and stage
1037 3. If this happens, make the stage 4 compiler and compare it to
1038 the stage 3 compiler. If the stage 3 and stage 4 object files are
1039 identical, this suggests you encountered a problem with the
1040 standard C compiler; the stage 3 and 4 compilers may be usable.
1042 It is best, however, to use an older version of GNU CC for
1043 bootstrapping if you have one.
1046 Motorola m88k running DG/UX. To build 88open BCS native or cross
1047 compilers on DG/UX, specify the configuration name as
1048 `m88k-*-dguxbcs' and build in the 88open BCS software development
1049 environment. To build ELF native or cross compilers on DG/UX,
1050 specify `m88k-*-dgux' and build in the DG/UX ELF development
1051 environment. You set the software development environment by
1052 issuing `sde-target' command and specifying either `m88kbcs' or
1053 `m88kdguxelf' as the operand.
1055 If you do not specify a configuration name, `configure' guesses the
1056 configuration based on the current software development
1059 `m88k-tektronix-sysv3'
1060 Tektronix XD88 running UTekV 3.2e. Do not turn on optimization
1061 while building stage1 if you bootstrap with the buggy Green Hills
1062 compiler. Also, The bundled LAI System V NFS is buggy so if you
1063 build in an NFS mounted directory, start from a fresh reboot, or
1064 avoid NFS all together. Otherwise you may have trouble getting
1065 clean comparisons between stages.
1068 MIPS machines running the MIPS operating system in BSD mode. It's
1069 possible that some old versions of the system lack the functions
1070 `memcpy', `memcmp', and `memset'. If your system lacks these, you
1071 must remove or undo the definition of `TARGET_MEM_FUNCTIONS' in
1074 The MIPS C compiler needs to be told to increase its table size
1075 for switch statements with the `-Wf,-XNg1500' option in order to
1076 compile `cp/parse.c'. If you use the `-O2' optimization option,
1077 you also need to use `-Olimit 3000'. Both of these options are
1078 automatically generated in the `Makefile' that the shell script
1079 `configure' builds. If you override the `CC' make variable and
1080 use the MIPS compilers, you may need to add `-Wf,-XNg1500 -Olimit
1084 The MIPS C compiler needs to be told to increase its table size
1085 for switch statements with the `-Wf,-XNg1500' option in order to
1086 compile `cp/parse.c'. If you use the `-O2' optimization option,
1087 you also need to use `-Olimit 3000'. Both of these options are
1088 automatically generated in the `Makefile' that the shell script
1089 `configure' builds. If you override the `CC' make variable and
1090 use the MIPS compilers, you may need to add `-Wf,-XNg1500 -Olimit
1093 MIPS computers running RISC-OS can support four different
1094 personalities: default, BSD 4.3, System V.3, and System V.4 (older
1095 versions of RISC-OS don't support V.4). To configure GCC for
1096 these platforms use the following configurations:
1098 `mips-mips-riscos`rev''
1099 Default configuration for RISC-OS, revision `rev'.
1101 `mips-mips-riscos`rev'bsd'
1102 BSD 4.3 configuration for RISC-OS, revision `rev'.
1104 `mips-mips-riscos`rev'sysv4'
1105 System V.4 configuration for RISC-OS, revision `rev'.
1107 `mips-mips-riscos`rev'sysv'
1108 System V.3 configuration for RISC-OS, revision `rev'.
1110 The revision `rev' mentioned above is the revision of RISC-OS to
1111 use. You must reconfigure GCC when going from a RISC-OS revision
1112 4 to RISC-OS revision 5. This has the effect of avoiding a linker
1116 In order to compile GCC on an SGI running IRIX 4, the "c.hdr.lib"
1117 option must be installed from the CD-ROM supplied from Silicon
1118 Graphics. This is found on the 2nd CD in release 4.0.1.
1120 In order to compile GCC on an SGI running IRIX 5, the
1121 "compiler_dev.hdr" subsystem must be installed from the IDO CD-ROM
1122 supplied by Silicon Graphics.
1124 `make compare' may fail on version 5 of IRIX unless you add
1125 `-save-temps' to `CFLAGS'. On these systems, the name of the
1126 assembler input file is stored in the object file, and that makes
1127 comparison fail if it differs between the `stage1' and `stage2'
1128 compilations. The option `-save-temps' forces a fixed name to be
1129 used for the assembler input file, instead of a randomly chosen
1130 name in `/tmp'. Do not add `-save-temps' unless the comparisons
1131 fail without that option. If you do you `-save-temps', you will
1132 have to manually delete the `.i' and `.s' files after each series
1135 The MIPS C compiler needs to be told to increase its table size
1136 for switch statements with the `-Wf,-XNg1500' option in order to
1137 compile `cp/parse.c'. If you use the `-O2' optimization option,
1138 you also need to use `-Olimit 3000'. Both of these options are
1139 automatically generated in the `Makefile' that the shell script
1140 `configure' builds. If you override the `CC' make variable and
1141 use the MIPS compilers, you may need to add `-Wf,-XNg1500 -Olimit
1144 On Irix version 4.0.5F, and perhaps on some other versions as well,
1145 there is an assembler bug that reorders instructions incorrectly.
1146 To work around it, specify the target configuration
1147 `mips-sgi-irix4loser'. This configuration inhibits assembler
1150 In a compiler configured with target `mips-sgi-irix4', you can turn
1151 off assembler optimization by using the `-noasmopt' option. This
1152 compiler option passes the option `-O0' to the assembler, to
1155 The `-noasmopt' option can be useful for testing whether a problem
1156 is due to erroneous assembler reordering. Even if a problem does
1157 not go away with `-noasmopt', it may still be due to assembler
1158 reordering--perhaps GNU CC itself was miscompiled as a result.
1160 To enable debugging under Irix 5, you must use GNU as 2.5 or later,
1161 and use the `--with-gnu-as' configure option when configuring gcc.
1162 GNU as is distributed as part of the binutils package.
1165 Sony MIPS NEWS. This works in NEWSOS 5.0.1, but not in 5.0.2
1166 (which uses ELF instead of COFF). Support for 5.0.2 will probably
1167 be provided soon by volunteers. In particular, the linker does
1168 not like the code generated by GCC when shared libraries are
1172 Encore ns32000 system. Encore systems are supported only under
1176 National Semiconductor ns32000 system. Genix has bugs in `alloca'
1177 and `malloc'; you must get the compiled versions of these from GNU
1181 Go to the Berkeley universe before compiling.
1184 UTEK ns32000 system ("merlin"). The C compiler that comes with
1185 this system cannot compile GNU CC; contact `tektronix!reed!mason'
1186 to get binaries of GNU CC for bootstrapping.
1190 The only operating systems supported for the IBM RT PC are AOS and
1191 MACH. GNU CC does not support AIX running on the RT. We
1192 recommend you compile GNU CC with an earlier version of itself; if
1193 you compile GNU CC with `hc', the Metaware compiler, it will work,
1194 but you will get mismatches between the stage 2 and stage 3
1195 compilers in various files. These errors are minor differences in
1196 some floating-point constants and can be safely ignored; the stage
1197 3 compiler is correct.
1201 Various early versions of each release of the IBM XLC compiler
1202 will not bootstrap GNU CC. Symptoms include differences between
1203 the stage2 and stage3 object files, and errors when compiling
1204 `libgcc.a' or `enquire'. Known problematic releases include:
1205 xlc-1.2.1.8, xlc-1.3.0.0 (distributed with AIX 3.2.5), and
1206 xlc-1.3.0.19. Both xlc-1.2.1.28 and xlc-1.3.0.24 (PTF 432238) are
1207 known to produce working versions of GNU CC, but most other recent
1208 releases correctly bootstrap GNU CC. Also, releases of AIX prior
1209 to AIX 3.2.4 include a version of the IBM assembler which does not
1210 accept debugging directives: assembler updates are available as
1211 PTFs. Also, if you are using AIX 3.2.5 or greater and the GNU
1212 assembler, you must have a version modified after October 16th,
1213 1995 in order for the GNU C compiler to build. See the file
1214 `README.RS6000' for more details on of these problems.
1216 GNU CC does not yet support the 64-bit PowerPC instructions.
1218 Objective C does not work on this architecture because it makes
1219 assumptions that are incompatible with the calling conventions.
1221 AIX on the RS/6000 provides support (NLS) for environments outside
1222 of the United States. Compilers and assemblers use NLS to support
1223 locale-specific representations of various objects including
1224 floating-point numbers ("." vs "," for separating decimal
1225 fractions). There have been problems reported where the library
1226 linked with GNU CC does not produce the same floating-point
1227 formats that the assembler accepts. If you have this problem, set
1228 the LANG environment variable to "C" or "En_US".
1230 Due to changes in the way that GNU CC invokes the binder (linker)
1231 for AIX 4.1, you may now receive warnings of duplicate symbols
1232 from the link step that were not reported before. The assembly
1233 files generated by GNU CC for AIX have always included multiple
1234 symbol definitions for certain global variable and function
1235 declarations in the original program. The warnings should not
1236 prevent the linker from producing a correct library or runnable
1239 By default, AIX 4.1 produces code that can be used on either Power
1240 or PowerPC processors.
1242 You can specify a default version for the `-mcpu='CPU_TYPE switch
1243 by using the configure option `--with-cpu-'CPU_TYPE.
1247 PowerPC system in big endian mode, running System V.4.
1249 You can specify a default version for the `-mcpu='CPU_TYPE switch
1250 by using the configure option `--with-cpu-'CPU_TYPE.
1252 `powerpc-*-linux-gnu'
1253 PowerPC system in big endian mode, running the Linux-based GNU
1256 You can specify a default version for the `-mcpu='CPU_TYPE switch
1257 by using the configure option `--with-cpu-'CPU_TYPE.
1260 Embedded PowerPC system in big endian mode with -mcall-aix
1261 selected as the default.
1263 You can specify a default version for the `-mcpu='CPU_TYPE switch
1264 by using the configure option `--with-cpu-'CPU_TYPE.
1267 Embedded PowerPC system in big endian mode for use in running
1268 under the PSIM simulator.
1270 You can specify a default version for the `-mcpu='CPU_TYPE switch
1271 by using the configure option `--with-cpu-'CPU_TYPE.
1274 Embedded PowerPC system in big endian mode.
1276 You can specify a default version for the `-mcpu='CPU_TYPE switch
1277 by using the configure option `--with-cpu-'CPU_TYPE.
1281 PowerPC system in little endian mode, running System V.4.
1283 You can specify a default version for the `-mcpu='CPU_TYPE switch
1284 by using the configure option `--with-cpu-'CPU_TYPE.
1286 `powerpcle-*-solaris2*'
1287 PowerPC system in little endian mode, running Solaris 2.5.1 or
1290 You can specify a default version for the `-mcpu='CPU_TYPE switch
1291 by using the configure option `--with-cpu-'CPU_TYPE. Beta
1292 versions of the Sun 4.0 compiler do not seem to be able to build
1293 GNU CC correctly. There are also problems with the host assembler
1294 and linker that are fixed by using the GNU versions of these tools.
1296 `powerpcle-*-eabisim'
1297 Embedded PowerPC system in little endian mode for use in running
1298 under the PSIM simulator.
1301 Embedded PowerPC system in little endian mode.
1303 You can specify a default version for the `-mcpu='CPU_TYPE switch
1304 by using the configure option `--with-cpu-'CPU_TYPE.
1308 PowerPC system in little endian mode running Windows NT.
1310 You can specify a default version for the `-mcpu='CPU_TYPE switch
1311 by using the configure option `--with-cpu-'CPU_TYPE.
1314 Don't try compiling with Vax C (`vcc'). It produces incorrect code
1315 in some cases (for example, when `alloca' is used).
1317 Meanwhile, compiling `cp/parse.c' with pcc does not work because of
1318 an internal table size limitation in that compiler. To avoid this
1319 problem, compile just the GNU C compiler first, and use it to
1320 recompile building all the languages that you want to run.
1323 See *Note Sun Install::, for information on installing GNU CC on
1327 See *Note VMS Install::, for details on how to install GNU CC on
1331 These computers are also known as the 3b2, 3b5, 3b20 and other
1332 similar names. (However, the 3b1 is actually a 68000; see *Note
1335 Don't use `-g' when compiling with the system's compiler. The
1336 system's linker seems to be unable to handle such a large program
1337 with debugging information.
1339 The system's compiler runs out of capacity when compiling `stmt.c'
1340 in GNU CC. You can work around this by building `cpp' in GNU CC
1341 first, then use that instead of the system's preprocessor with the
1342 system's C compiler to compile `stmt.c'. Here is how:
1344 mv /lib/cpp /lib/cpp.att
1346 echo '/lib/cpp.gnu -traditional ${1+"$@"}' > /lib/cpp
1349 The system's compiler produces bad code for some of the GNU CC
1350 optimization files. So you must build the stage 2 compiler without
1351 optimization. Then build a stage 3 compiler with optimization.
1352 That executable should work. Here are the necessary commands:
1354 make LANGUAGES=c CC=stage1/xgcc CFLAGS="-Bstage1/ -g"
1356 make CC=stage2/xgcc CFLAGS="-Bstage2/ -g -O"
1358 You may need to raise the ULIMIT setting to build a C++ compiler,
1359 as the file `cc1plus' is larger than one megabyte.
1361 Compilation in a Separate Directory
1362 ===================================
1364 If you wish to build the object files and executables in a directory
1365 other than the one containing the source files, here is what you must
1368 1. Make sure you have a version of Make that supports the `VPATH'
1369 feature. (GNU Make supports it, as do Make versions on most BSD
1372 2. If you have ever run `configure' in the source directory, you must
1373 undo the configuration. Do this by running:
1377 3. Go to the directory in which you want to build the compiler before
1378 running `configure':
1383 On systems that do not support symbolic links, this directory must
1384 be on the same file system as the source code directory.
1386 4. Specify where to find `configure' when you run it:
1388 ../gcc/configure ...
1390 This also tells `configure' where to find the compiler sources;
1391 `configure' takes the directory from the file name that was used to
1392 invoke it. But if you want to be sure, you can specify the source
1393 directory with the `--srcdir' option, like this:
1395 ../gcc/configure --srcdir=../gcc OTHER OPTIONS
1397 The directory you specify with `--srcdir' need not be the same as
1398 the one that `configure' is found in.
1400 Now, you can run `make' in that directory. You need not repeat the
1401 configuration steps shown above, when ordinary source files change. You
1402 must, however, run `configure' again when the configuration files
1403 change, if your system does not support symbolic links.
1405 Building and Installing a Cross-Compiler
1406 ========================================
1408 GNU CC can function as a cross-compiler for many machines, but not
1411 * Cross-compilers for the Mips as target using the Mips assembler
1412 currently do not work, because the auxiliary programs
1413 `mips-tdump.c' and `mips-tfile.c' can't be compiled on anything
1414 but a Mips. It does work to cross compile for a Mips if you use
1415 the GNU assembler and linker.
1417 * Cross-compilers between machines with different floating point
1418 formats have not all been made to work. GNU CC now has a floating
1419 point emulator with which these can work, but each target machine
1420 description needs to be updated to take advantage of it.
1422 * Cross-compilation between machines of different word sizes is
1423 somewhat problematic and sometimes does not work.
1425 Since GNU CC generates assembler code, you probably need a
1426 cross-assembler that GNU CC can run, in order to produce object files.
1427 If you want to link on other than the target machine, you need a
1428 cross-linker as well. You also need header files and libraries suitable
1429 for the target machine that you can install on the host machine.
1431 Steps of Cross-Compilation
1432 --------------------------
1434 To compile and run a program using a cross-compiler involves several
1437 * Run the cross-compiler on the host machine to produce assembler
1438 files for the target machine. This requires header files for the
1441 * Assemble the files produced by the cross-compiler. You can do this
1442 either with an assembler on the target machine, or with a
1443 cross-assembler on the host machine.
1445 * Link those files to make an executable. You can do this either
1446 with a linker on the target machine, or with a cross-linker on the
1447 host machine. Whichever machine you use, you need libraries and
1448 certain startup files (typically `crt....o') for the target
1451 It is most convenient to do all of these steps on the same host
1452 machine, since then you can do it all with a single invocation of GNU
1453 CC. This requires a suitable cross-assembler and cross-linker. For
1454 some targets, the GNU assembler and linker are available.
1456 Configuring a Cross-Compiler
1457 ----------------------------
1459 To build GNU CC as a cross-compiler, you start out by running
1460 `configure'. Use the `--target=TARGET' to specify the target type. If
1461 `configure' was unable to correctly identify the system you are running
1462 on, also specify the `--build=BUILD' option. For example, here is how
1463 to configure for a cross-compiler that produces code for an HP 68030
1464 system running BSD on a system that `configure' can correctly identify:
1466 ./configure --target=m68k-hp-bsd4.3
1468 Tools and Libraries for a Cross-Compiler
1469 ----------------------------------------
1471 If you have a cross-assembler and cross-linker available, you should
1472 install them now. Put them in the directory `/usr/local/TARGET/bin'.
1473 Here is a table of the tools you should put in this directory:
1476 This should be the cross-assembler.
1479 This should be the cross-linker.
1482 This should be the cross-archiver: a program which can manipulate
1483 archive files (linker libraries) in the target machine's format.
1486 This should be a program to construct a symbol table in an archive
1489 The installation of GNU CC will find these programs in that
1490 directory, and copy or link them to the proper place to for the
1491 cross-compiler to find them when run later.
1493 The easiest way to provide these files is to build the Binutils
1494 package and GAS. Configure them with the same `--host' and `--target'
1495 options that you use for configuring GNU CC, then build and install
1496 them. They install their executables automatically into the proper
1497 directory. Alas, they do not support all the targets that GNU CC
1500 If you want to install libraries to use with the cross-compiler,
1501 such as a standard C library, put them in the directory
1502 `/usr/local/TARGET/lib'; installation of GNU CC copies all the files in
1503 that subdirectory into the proper place for GNU CC to find them and
1504 link with them. Here's an example of copying some libraries from a
1508 lcd /usr/local/TARGET/lib
1516 The precise set of libraries you'll need, and their locations on the
1517 target machine, vary depending on its operating system.
1519 Many targets require "start files" such as `crt0.o' and `crtn.o'
1520 which are linked into each executable; these too should be placed in
1521 `/usr/local/TARGET/lib'. There may be several alternatives for
1522 `crt0.o', for use with profiling or other compilation options. Check
1523 your target's definition of `STARTFILE_SPEC' to find out what start
1524 files it uses. Here's an example of copying these files from a target
1528 lcd /usr/local/TARGET/lib
1536 `libgcc.a' and Cross-Compilers
1537 ------------------------------
1539 Code compiled by GNU CC uses certain runtime support functions
1540 implicitly. Some of these functions can be compiled successfully with
1541 GNU CC itself, but a few cannot be. These problem functions are in the
1542 source file `libgcc1.c'; the library made from them is called
1545 When you build a native compiler, these functions are compiled with
1546 some other compiler-the one that you use for bootstrapping GNU CC.
1547 Presumably it knows how to open code these operations, or else knows how
1548 to call the run-time emulation facilities that the machine comes with.
1549 But this approach doesn't work for building a cross-compiler. The
1550 compiler that you use for building knows about the host system, not the
1553 So, when you build a cross-compiler you have to supply a suitable
1554 library `libgcc1.a' that does the job it is expected to do.
1556 To compile `libgcc1.c' with the cross-compiler itself does not work.
1557 The functions in this file are supposed to implement arithmetic
1558 operations that GNU CC does not know how to open code for your target
1559 machine. If these functions are compiled with GNU CC itself, they will
1560 compile into infinite recursion.
1562 On any given target, most of these functions are not needed. If GNU
1563 CC can open code an arithmetic operation, it will not call these
1564 functions to perform the operation. It is possible that on your target
1565 machine, none of these functions is needed. If so, you can supply an
1566 empty library as `libgcc1.a'.
1568 Many targets need library support only for multiplication and
1569 division. If you are linking with a library that contains functions for
1570 multiplication and division, you can tell GNU CC to call them directly
1571 by defining the macros `MULSI3_LIBCALL', and the like. These macros
1572 need to be defined in the target description macro file. For some
1573 targets, they are defined already. This may be sufficient to avoid the
1574 need for libgcc1.a; if so, you can supply an empty library.
1576 Some targets do not have floating point instructions; they need other
1577 functions in `libgcc1.a', which do floating arithmetic. Recent
1578 versions of GNU CC have a file which emulates floating point. With a
1579 certain amount of work, you should be able to construct a floating
1580 point emulator that can be used as `libgcc1.a'. Perhaps future
1581 versions will contain code to do this automatically and conveniently.
1582 That depends on whether someone wants to implement it.
1584 Some embedded targets come with all the necessary `libgcc1.a'
1585 routines written in C or assembler. These targets build `libgcc1.a'
1586 automatically and you do not need to do anything special for them.
1587 Other embedded targets do not need any `libgcc1.a' routines since all
1588 the necessary operations are supported by the hardware.
1590 If your target system has another C compiler, you can configure GNU
1591 CC as a native compiler on that machine, build just `libgcc1.a' with
1592 `make libgcc1.a' on that machine, and use the resulting file with the
1593 cross-compiler. To do this, execute the following on the target
1597 ./configure --host=sparc --target=sun3
1600 And then this on the host machine:
1608 Another way to provide the functions you need in `libgcc1.a' is to
1609 define the appropriate `perform_...' macros for those functions. If
1610 these definitions do not use the C arithmetic operators that they are
1611 meant to implement, you should be able to compile them with the
1612 cross-compiler you are building. (If these definitions already exist
1613 for your target file, then you are all set.)
1615 To build `libgcc1.a' using the perform macros, use
1616 `LIBGCC1=libgcc1.a OLDCC=./xgcc' when building the compiler.
1617 Otherwise, you should place your replacement library under the name
1618 `libgcc1.a' in the directory in which you will build the
1619 cross-compiler, before you run `make'.
1621 Cross-Compilers and Header Files
1622 --------------------------------
1624 If you are cross-compiling a standalone program or a program for an
1625 embedded system, then you may not need any header files except the few
1626 that are part of GNU CC (and those of your program). However, if you
1627 intend to link your program with a standard C library such as `libc.a',
1628 then you probably need to compile with the header files that go with
1629 the library you use.
1631 The GNU C compiler does not come with these files, because (1) they
1632 are system-specific, and (2) they belong in a C library, not in a
1635 If the GNU C library supports your target machine, then you can get
1636 the header files from there (assuming you actually use the GNU library
1637 when you link your program).
1639 If your target machine comes with a C compiler, it probably comes
1640 with suitable header files also. If you make these files accessible
1641 from the host machine, the cross-compiler can use them also.
1643 Otherwise, you're on your own in finding header files to use when
1646 When you have found suitable header files, put them in the directory
1647 `/usr/local/TARGET/include', before building the cross compiler. Then
1648 installation will run fixincludes properly and install the corrected
1649 versions of the header files where the compiler will use them.
1651 Provide the header files before you build the cross-compiler, because
1652 the build stage actually runs the cross-compiler to produce parts of
1653 `libgcc.a'. (These are the parts that *can* be compiled with GNU CC.)
1654 Some of them need suitable header files.
1656 Here's an example showing how to copy the header files from a target
1657 machine. On the target machine, do this:
1659 (cd /usr/include; tar cf - .) > tarfile
1661 Then, on the host machine, do this:
1664 lcd /usr/local/TARGET/include
1669 Actually Building the Cross-Compiler
1670 ------------------------------------
1672 Now you can proceed just as for compiling a single-machine compiler
1673 through the step of building stage 1. If you have not provided some
1674 sort of `libgcc1.a', then compilation will give up at the point where
1675 it needs that file, printing a suitable error message. If you do
1676 provide `libgcc1.a', then building the compiler will automatically
1677 compile and link a test program called `libgcc1-test'; if you get
1678 errors in the linking, it means that not all of the necessary routines
1679 in `libgcc1.a' are available.
1681 You must provide the header file `float.h'. One way to do this is
1682 to compile `enquire' and run it on your target machine. The job of
1683 `enquire' is to run on the target machine and figure out by experiment
1684 the nature of its floating point representation. `enquire' records its
1685 findings in the header file `float.h'. If you can't produce this file
1686 by running `enquire' on the target machine, then you will need to come
1687 up with a suitable `float.h' in some other way (or else, avoid using it
1690 Do not try to build stage 2 for a cross-compiler. It doesn't work to
1691 rebuild GNU CC as a cross-compiler using the cross-compiler, because
1692 that would produce a program that runs on the target machine, not on the
1693 host. For example, if you compile a 386-to-68030 cross-compiler with
1694 itself, the result will not be right either for the 386 (because it was
1695 compiled into 68030 code) or for the 68030 (because it was configured
1696 for a 386 as the host). If you want to compile GNU CC into 68030 code,
1697 whether you compile it on a 68030 or with a cross-compiler on a 386, you
1698 must specify a 68030 as the host when you configure it.
1700 To install the cross-compiler, use `make install', as usual.
1702 Installing GNU CC on the Sun
1703 ============================
1705 On Solaris (version 2.1), do not use the linker or other tools in
1706 `/usr/ucb' to build GNU CC. Use `/usr/ccs/bin'.
1708 Make sure the environment variable `FLOAT_OPTION' is not set when
1709 you compile `libgcc.a'. If this option were set to `f68881' when
1710 `libgcc.a' is compiled, the resulting code would demand to be linked
1711 with a special startup file and would not link properly without special
1714 There is a bug in `alloca' in certain versions of the Sun library.
1715 To avoid this bug, install the binaries of GNU CC that were compiled by
1716 GNU CC. They use `alloca' as a built-in function and never the one in
1719 Some versions of the Sun compiler crash when compiling GNU CC. The
1720 problem is a segmentation fault in cpp. This problem seems to be due to
1721 the bulk of data in the environment variables. You may be able to avoid
1722 it by using the following command to compile GNU CC with Sun CC:
1724 make CC="TERMCAP=x OBJS=x LIBFUNCS=x STAGESTUFF=x cc"
1726 SunOS 4.1.3 and 4.1.3_U1 have bugs that can cause intermittent core
1727 dumps when compiling GNU CC. A common symptom is an internal compiler
1728 error which does not recur if you run it again. To fix the problem,
1729 install Sun recommended patch 100726 (for SunOS 4.1.3) or 101508 (for
1730 SunOS 4.1.3_U1), or upgrade to a later SunOS release.
1732 Installing GNU CC on VMS
1733 ========================
1735 The VMS version of GNU CC is distributed in a backup saveset
1736 containing both source code and precompiled binaries.
1738 To install the `gcc' command so you can use the compiler easily, in
1739 the same manner as you use the VMS C compiler, you must install the VMS
1740 CLD file for GNU CC as follows:
1742 1. Define the VMS logical names `GNU_CC' and `GNU_CC_INCLUDE' to
1743 point to the directories where the GNU CC executables
1744 (`gcc-cpp.exe', `gcc-cc1.exe', etc.) and the C include files are
1745 kept respectively. This should be done with the commands:
1747 $ assign /system /translation=concealed -
1749 $ assign /system /translation=concealed -
1750 disk:[gcc.include.] gnu_cc_include
1752 with the appropriate disk and directory names. These commands can
1753 be placed in your system startup file so they will be executed
1754 whenever the machine is rebooted. You may, if you choose, do this
1755 via the `GCC_INSTALL.COM' script in the `[GCC]' directory.
1757 2. Install the `GCC' command with the command line:
1759 $ set command /table=sys$common:[syslib]dcltables -
1760 /output=sys$common:[syslib]dcltables gnu_cc:[000000]gcc
1761 $ install replace sys$common:[syslib]dcltables
1763 3. To install the help file, do the following:
1765 $ library/help sys$library:helplib.hlb gcc.hlp
1767 Now you can invoke the compiler with a command like `gcc /verbose
1768 file.c', which is equivalent to the command `gcc -v -c file.c' in
1771 If you wish to use GNU C++ you must first install GNU CC, and then
1772 perform the following steps:
1774 1. Define the VMS logical name `GNU_GXX_INCLUDE' to point to the
1775 directory where the preprocessor will search for the C++ header
1776 files. This can be done with the command:
1778 $ assign /system /translation=concealed -
1779 disk:[gcc.gxx_include.] gnu_gxx_include
1781 with the appropriate disk and directory name. If you are going to
1782 be using libg++, this is where the libg++ install procedure will
1783 install the libg++ header files.
1785 2. Obtain the file `gcc-cc1plus.exe', and place this in the same
1786 directory that `gcc-cc1.exe' is kept.
1788 The GNU C++ compiler can be invoked with a command like `gcc /plus
1789 /verbose file.cc', which is equivalent to the command `g++ -v -c
1792 We try to put corresponding binaries and sources on the VMS
1793 distribution tape. But sometimes the binaries will be from an older
1794 version than the sources, because we don't always have time to update
1795 them. (Use the `/version' option to determine the version number of
1796 the binaries and compare it with the source file `version.c' to tell
1797 whether this is so.) In this case, you should use the binaries you get
1798 to recompile the sources. If you must recompile, here is how:
1800 1. Execute the command procedure `vmsconfig.com' to set up the files
1801 `tm.h', `config.h', `aux-output.c', and `md.', and to create files
1802 `tconfig.h' and `hconfig.h'. This procedure also creates several
1803 linker option files used by `make-cc1.com' and a data file used by
1808 2. Setup the logical names and command tables as defined above. In
1809 addition, define the VMS logical name `GNU_BISON' to point at the
1810 to the directories where the Bison executable is kept. This
1811 should be done with the command:
1813 $ assign /system /translation=concealed -
1814 disk:[bison.] gnu_bison
1816 You may, if you choose, use the `INSTALL_BISON.COM' script in the
1817 `[BISON]' directory.
1819 3. Install the `BISON' command with the command line:
1821 $ set command /table=sys$common:[syslib]dcltables -
1822 /output=sys$common:[syslib]dcltables -
1823 gnu_bison:[000000]bison
1824 $ install replace sys$common:[syslib]dcltables
1826 4. Type `@make-gcc' to recompile everything (alternatively, submit
1827 the file `make-gcc.com' to a batch queue). If you wish to build
1828 the GNU C++ compiler as well as the GNU CC compiler, you must
1829 first edit `make-gcc.com' and follow the instructions that appear
1832 5. In order to use GCC, you need a library of functions which GCC
1833 compiled code will call to perform certain tasks, and these
1834 functions are defined in the file `libgcc2.c'. To compile this
1835 you should use the command procedure `make-l2.com', which will
1836 generate the library `libgcc2.olb'. `libgcc2.olb' should be built
1837 using the compiler built from the same distribution that
1838 `libgcc2.c' came from, and `make-gcc.com' will automatically do
1839 all of this for you.
1841 To install the library, use the following commands:
1843 $ library gnu_cc:[000000]gcclib/delete=(new,eprintf)
1844 $ library gnu_cc:[000000]gcclib/delete=L_*
1845 $ library libgcc2/extract=*/output=libgcc2.obj
1846 $ library gnu_cc:[000000]gcclib libgcc2.obj
1848 The first command simply removes old modules that will be replaced
1849 with modules from `libgcc2' under different module names. The
1850 modules `new' and `eprintf' may not actually be present in your
1851 `gcclib.olb'--if the VMS librarian complains about those modules
1852 not being present, simply ignore the message and continue on with
1853 the next command. The second command removes the modules that
1854 came from the previous version of the library `libgcc2.c'.
1856 Whenever you update the compiler on your system, you should also
1857 update the library with the above procedure.
1859 6. You may wish to build GCC in such a way that no files are written
1860 to the directory where the source files reside. An example would
1861 be the when the source files are on a read-only disk. In these
1862 cases, execute the following DCL commands (substituting your
1865 $ assign dua0:[gcc.build_dir.]/translation=concealed, -
1866 dua1:[gcc.source_dir.]/translation=concealed gcc_build
1867 $ set default gcc_build:[000000]
1869 where the directory `dua1:[gcc.source_dir]' contains the source
1870 code, and the directory `dua0:[gcc.build_dir]' is meant to contain
1871 all of the generated object files and executables. Once you have
1872 done this, you can proceed building GCC as described above. (Keep
1873 in mind that `gcc_build' is a rooted logical name, and thus the
1874 device names in each element of the search list must be an actual
1875 physical device name rather than another rooted logical name).
1877 7. *If you are building GNU CC with a previous version of GNU CC, you
1878 also should check to see that you have the newest version of the
1879 assembler*. In particular, GNU CC version 2 treats global constant
1880 variables slightly differently from GNU CC version 1, and GAS
1881 version 1.38.1 does not have the patches required to work with GCC
1882 version 2. If you use GAS 1.38.1, then `extern const' variables
1883 will not have the read-only bit set, and the linker will generate
1884 warning messages about mismatched psect attributes for these
1885 variables. These warning messages are merely a nuisance, and can
1888 If you are compiling with a version of GNU CC older than 1.33,
1889 specify `/DEFINE=("inline=")' as an option in all the
1890 compilations. This requires editing all the `gcc' commands in
1891 `make-cc1.com'. (The older versions had problems supporting
1892 `inline'.) Once you have a working 1.33 or newer GNU CC, you can
1893 change this file back.
1895 8. If you want to build GNU CC with the VAX C compiler, you will need
1896 to make minor changes in `make-cccp.com' and `make-cc1.com' to
1897 choose alternate definitions of `CC', `CFLAGS', and `LIBS'. See
1898 comments in those files. However, you must also have a working
1899 version of the GNU assembler (GNU as, aka GAS) as it is used as
1900 the back-end for GNU CC to produce binary object modules and is
1901 not included in the GNU CC sources. GAS is also needed to compile
1902 `libgcc2' in order to build `gcclib' (see above); `make-l2.com'
1903 expects to be able to find it operational in
1904 `gnu_cc:[000000]gnu-as.exe'.
1906 To use GNU CC on VMS, you need the VMS driver programs `gcc.exe',
1907 `gcc.com', and `gcc.cld'. They are distributed with the VMS
1908 binaries (`gcc-vms') rather than the GNU CC sources. GAS is also
1909 included in `gcc-vms', as is Bison.
1911 Once you have successfully built GNU CC with VAX C, you should use
1912 the resulting compiler to rebuild itself. Before doing this, be
1913 sure to restore the `CC', `CFLAGS', and `LIBS' definitions in
1914 `make-cccp.com' and `make-cc1.com'. The second generation
1915 compiler will be able to take advantage of many optimizations that
1916 must be suppressed when building with other compilers.
1918 Under previous versions of GNU CC, the generated code would
1919 occasionally give strange results when linked with the sharable
1920 `VAXCRTL' library. Now this should work.
1922 Even with this version, however, GNU CC itself should not be linked
1923 with the sharable `VAXCRTL'. The version of `qsort' in `VAXCRTL' has a
1924 bug (known to be present in VMS versions V4.6 through V5.5) which
1925 causes the compiler to fail.
1927 The executables are generated by `make-cc1.com' and `make-cccp.com'
1928 use the object library version of `VAXCRTL' in order to make use of the
1929 `qsort' routine in `gcclib.olb'. If you wish to link the compiler
1930 executables with the shareable image version of `VAXCRTL', you should
1931 edit the file `tm.h' (created by `vmsconfig.com') to define the macro
1934 `QSORT_WORKAROUND' is always defined when GNU CC is compiled with
1935 VAX C, to avoid a problem in case `gcclib.olb' is not yet available.
1940 Many target systems do not have support in the assembler and linker
1941 for "constructors"--initialization functions to be called before the
1942 official "start" of `main'. On such systems, GNU CC uses a utility
1943 called `collect2' to arrange to call these functions at start time.
1945 The program `collect2' works by linking the program once and looking
1946 through the linker output file for symbols with particular names
1947 indicating they are constructor functions. If it finds any, it creates
1948 a new temporary `.c' file containing a table of them, compiles it, and
1949 links the program a second time including that file.
1951 The actual calls to the constructors are carried out by a subroutine
1952 called `__main', which is called (automatically) at the beginning of
1953 the body of `main' (provided `main' was compiled with GNU CC). Calling
1954 `__main' is necessary, even when compiling C code, to allow linking C
1955 and C++ object code together. (If you use `-nostdlib', you get an
1956 unresolved reference to `__main', since it's defined in the standard
1957 GCC library. Include `-lgcc' at the end of your compiler command line
1958 to resolve this reference.)
1960 The program `collect2' is installed as `ld' in the directory where
1961 the passes of the compiler are installed. When `collect2' needs to
1962 find the *real* `ld', it tries the following file names:
1964 * `real-ld' in the directories listed in the compiler's search
1967 * `real-ld' in the directories listed in the environment variable
1970 * The file specified in the `REAL_LD_FILE_NAME' configuration macro,
1973 * `ld' in the compiler's search directories, except that `collect2'
1974 will not execute itself recursively.
1978 "The compiler's search directories" means all the directories where
1979 `gcc' searches for passes of the compiler. This includes directories
1980 that you specify with `-B'.
1982 Cross-compilers search a little differently:
1984 * `real-ld' in the compiler's search directories.
1986 * `TARGET-real-ld' in `PATH'.
1988 * The file specified in the `REAL_LD_FILE_NAME' configuration macro,
1991 * `ld' in the compiler's search directories.
1993 * `TARGET-ld' in `PATH'.
1995 `collect2' explicitly avoids running `ld' using the file name under
1996 which `collect2' itself was invoked. In fact, it remembers up a list
1997 of such names--in case one copy of `collect2' finds another copy (or
1998 version) of `collect2' installed as `ld' in a second place in the
2001 `collect2' searches for the utilities `nm' and `strip' using the
2002 same algorithm as above for `ld'.
2004 Standard Header File Directories
2005 ================================
2007 `GCC_INCLUDE_DIR' means the same thing for native and cross. It is
2008 where GNU CC stores its private include files, and also where GNU CC
2009 stores the fixed include files. A cross compiled GNU CC runs
2010 `fixincludes' on the header files in `$(tooldir)/include'. (If the
2011 cross compilation header files need to be fixed, they must be installed
2012 before GNU CC is built. If the cross compilation header files are
2013 already suitable for ANSI C and GNU CC, nothing special need be done).
2015 `GPLUS_INCLUDE_DIR' means the same thing for native and cross. It
2016 is where `g++' looks first for header files. `libg++' installs only
2017 target independent header files in that directory.
2019 `LOCAL_INCLUDE_DIR' is used only for a native compiler. It is
2020 normally `/usr/local/include'. GNU CC searches this directory so that
2021 users can install header files in `/usr/local/include'.
2023 `CROSS_INCLUDE_DIR' is used only for a cross compiler. GNU CC
2024 doesn't install anything there.
2026 `TOOL_INCLUDE_DIR' is used for both native and cross compilers. It
2027 is the place for other packages to install header files that GNU CC will
2028 use. For a cross-compiler, this is the equivalent of `/usr/include'.
2029 When you build a cross-compiler, `fixincludes' processes any header
2030 files in this directory.