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-threads=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 a C++ runtime library. Just as GNU C does not distribute
453 a C runtime library, it also does not include a C++ runtime
454 library. All I/O functionality, special class libraries, etc., are
455 provided by the C++ runtime library.
457 Here's one way to build and install a C++ runtime library for GNU
460 * Build and install GNU CC, so that invoking `gcc' obtains the
461 GNU CC that was just built.
463 * Obtain a copy of a compatible `libstdc++' distribution. For
464 example, the `libstdc++-2.8.0.tar.gz' distribution should be
465 compatible with GCC 2.8.0. GCC distributors normally
466 distribute `libstdc++' as well.
468 * Set the `CXX' environment variable to `gcc' while running the
469 `libstdc++' distribution's `configure' command. Use the same
470 `configure' options that you used when you invoked GCC's
473 * Invoke `make' to build the C++ runtime.
475 * Invoke `make install' to install the C++ runtime.
477 To summarize, after building and installing GNU CC, invoke the
478 following shell commands in the topmost directory of the C++
479 library distribution. For CONFIGURE-OPTIONS, use the same options
480 that you used to configure GNU CC.
482 $ CXX=gcc ./configure CONFIGURE-OPTIONS
486 17. GNU CC includes a runtime library for Objective-C because it is an
487 integral part of the language. You can find the files associated
488 with the library in the subdirectory `objc'. The GNU Objective-C
489 Runtime Library requires header files for the target's C library in
490 order to be compiled,and also requires the header files for the
491 target's thread library if you want thread support. *Note
492 Cross-Compilers and Header Files: Cross Headers, for discussion
493 about header files issues for cross-compilation.
495 When you run `configure', it picks the appropriate Objective-C
496 thread implementation file for the target platform. In some
497 situations, you may wish to choose a different back-end as some
498 platforms support multiple thread implementations or you may wish
499 to disable thread support completely. You do this by specifying a
500 value for the OBJC_THREAD_FILE makefile variable on the command
501 line when you run make, for example:
503 make CC="stage2/xgcc -Bstage2/" CFLAGS="-g -O2" OBJC_THREAD_FILE=thr-single
505 Below is a list of the currently available back-ends.
507 * thr-single Disable thread support, should work for all
510 * thr-decosf1 DEC OSF/1 thread support.
512 * thr-irix SGI IRIX thread support.
514 * thr-mach Generic MACH thread support, known to work on
517 * thr-os2 IBM OS/2 thread support.
519 * thr-posix Generix POSIX thread support.
521 * thr-pthreads PCThreads on Linux-based GNU systems.
523 * thr-solaris SUN Solaris thread support.
525 * thr-win32 Microsoft Win32 API thread support.
527 Configurations Supported by GNU CC
528 ==================================
530 Here are the possible CPU types:
532 1750a, a29k, alpha, arm, cN, clipper, dsp16xx, elxsi, h8300,
533 hppa1.0, hppa1.1, i370, i386, i486, i586, i860, i960, m32r,
534 m68000, m68k, m88k, mips, mipsel, mips64, mips64el, ns32k,
535 powerpc, powerpcle, pyramid, romp, rs6000, sh, sparc, sparclite,
538 Here are the recognized company names. As you can see, customary
539 abbreviations are used rather than the longer official names.
541 acorn, alliant, altos, apollo, apple, att, bull, cbm, convergent,
542 convex, crds, dec, dg, dolphin, elxsi, encore, harris, hitachi,
543 hp, ibm, intergraph, isi, mips, motorola, ncr, next, ns, omron,
544 plexus, sequent, sgi, sony, sun, tti, unicom, wrs.
546 The company name is meaningful only to disambiguate when the rest of
547 the information supplied is insufficient. You can omit it, writing
548 just `CPU-SYSTEM', if it is not needed. For example, `vax-ultrix4.2'
549 is equivalent to `vax-dec-ultrix4.2'.
551 Here is a list of system types:
553 386bsd, aix, acis, amigaos, aos, aout, aux, bosx, bsd, clix, coff,
554 ctix, cxux, dgux, dynix, ebmon, ecoff, elf, esix, freebsd, hms,
555 genix, gnu, linux-gnu, hiux, hpux, iris, irix, isc, luna, lynxos,
556 mach, minix, msdos, mvs, netbsd, newsos, nindy, ns, osf, osfrose,
557 ptx, riscix, riscos, rtu, sco, sim, solaris, sunos, sym, sysv,
558 udi, ultrix, unicos, uniplus, unos, vms, vsta, vxworks, winnt,
561 You can omit the system type; then `configure' guesses the operating
562 system from the CPU and company.
564 You can add a version number to the system type; this may or may not
565 make a difference. For example, you can write `bsd4.3' or `bsd4.4' to
566 distinguish versions of BSD. In practice, the version number is most
567 needed for `sysv3' and `sysv4', which are often treated differently.
569 If you specify an impossible combination such as `i860-dg-vms', then
570 you may get an error message from `configure', or it may ignore part of
571 the information and do the best it can with the rest. `configure'
572 always prints the canonical name for the alternative that it used. GNU
573 CC does not support all possible alternatives.
575 Often a particular model of machine has a name. Many machine names
576 are recognized as aliases for CPU/company combinations. Thus, the
577 machine name `sun3', mentioned above, is an alias for `m68k-sun'.
578 Sometimes we accept a company name as a machine name, when the name is
579 popularly used for a particular machine. Here is a table of the known
582 3300, 3b1, 3bN, 7300, altos3068, altos, apollo68, att-7300,
583 balance, convex-cN, crds, decstation-3100, decstation, delta,
584 encore, fx2800, gmicro, hp7NN, hp8NN, hp9k2NN, hp9k3NN, hp9k7NN,
585 hp9k8NN, iris4d, iris, isi68, m3230, magnum, merlin, miniframe,
586 mmax, news-3600, news800, news, next, pbd, pc532, pmax, powerpc,
587 powerpcle, ps2, risc-news, rtpc, sun2, sun386i, sun386, sun3,
588 sun4, symmetry, tower-32, tower.
590 Remember that a machine name specifies both the cpu type and the company
591 name. If you want to install your own homemade configuration files,
592 you can use `local' as the company name to access them. If you use
593 configuration `CPU-local', the configuration name without the cpu prefix
594 is used to form the configuration file names.
596 Thus, if you specify `m68k-local', configuration uses files
597 `m68k.md', `local.h', `m68k.c', `xm-local.h', `t-local', and `x-local',
598 all in the directory `config/m68k'.
600 Here is a list of configurations that have special treatment or
601 special things you must know:
604 MIL-STD-1750A processors.
606 The MIL-STD-1750A cross configuration produces output for
607 `as1750', an assembler/linker available under the GNU Public
608 License for the 1750A. `as1750' can be obtained at
609 *ftp://ftp.fta-berlin.de/pub/crossgcc/1750gals/*. A similarly
610 licensed simulator for the 1750A is available from same address.
612 You should ignore a fatal error during the building of libgcc
613 (libgcc is not yet implemented for the 1750A.)
615 The `as1750' assembler requires the file `ms1750.inc', which is
616 found in the directory `config/1750a'.
618 GNU CC produced the same sections as the Fairchild F9450 C
622 The program code section.
625 The read/write (RAM) data section.
628 The read-only (ROM) constants section.
631 Initialization section (code to copy KREL to SREL).
633 The smallest addressable unit is 16 bits (BITS_PER_UNIT is 16).
634 This means that type `char' is represented with a 16-bit word per
635 character. The 1750A's "Load/Store Upper/Lower Byte" instructions
636 are not used by GNU CC.
639 Systems using processors that implement the DEC Alpha architecture
640 and are running the DEC Unix (OSF/1) operating system, for example
641 the DEC Alpha AXP systems.CC.)
643 GNU CC writes a `.verstamp' directive to the assembler output file
644 unless it is built as a cross-compiler. It gets the version to
645 use from the system header file `/usr/include/stamp.h'. If you
646 install a new version of DEC Unix, you should rebuild GCC to pick
647 up the new version stamp.
649 Note that since the Alpha is a 64-bit architecture,
650 cross-compilers from 32-bit machines will not generate code as
651 efficient as that generated when the compiler is running on a
652 64-bit machine because many optimizations that depend on being
653 able to represent a word on the target in an integral value on the
654 host cannot be performed. Building cross-compilers on the Alpha
655 for 32-bit machines has only been tested in a few cases and may
658 `make compare' may fail on old versions of DEC Unix unless you add
659 `-save-temps' to `CFLAGS'. On these systems, the name of the
660 assembler input file is stored in the object file, and that makes
661 comparison fail if it differs between the `stage1' and `stage2'
662 compilations. The option `-save-temps' forces a fixed name to be
663 used for the assembler input file, instead of a randomly chosen
664 name in `/tmp'. Do not add `-save-temps' unless the comparisons
665 fail without that option. If you add `-save-temps', you will have
666 to manually delete the `.i' and `.s' files after each series of
669 GNU CC now supports both the native (ECOFF) debugging format used
670 by DBX and GDB and an encapsulated STABS format for use only with
671 GDB. See the discussion of the `--with-stabs' option of
672 `configure' above for more information on these formats and how to
675 There is a bug in DEC's assembler that produces incorrect line
676 numbers for ECOFF format when the `.align' directive is used. To
677 work around this problem, GNU CC will not emit such alignment
678 directives while writing ECOFF format debugging information even
679 if optimization is being performed. Unfortunately, this has the
680 very undesirable side-effect that code addresses when `-O' is
681 specified are different depending on whether or not `-g' is also
684 To avoid this behavior, specify `-gstabs+' and use GDB instead of
685 DBX. DEC is now aware of this problem with the assembler and
686 hopes to provide a fix shortly.
689 Argonaut ARC processor. This configuration is intended for
693 Advanced RISC Machines ARM-family processors. These are often
694 used in embedded applications. There are no standard Unix
695 configurations. This configuration corresponds to the basic
696 instruction sequences and will produce `a.out' format object
699 You may need to make a variant of the file `arm.h' for your
700 particular configuration.
703 Any of the ARM family processors running the Linux-based GNU
704 system with the `a.out' binary format (ELF is not yet supported).
705 You must use version 2.8.1.0.7 or later of the GNU/Linux binutils,
706 which you can download from `sunsite.unc.edu:/pub/Linux/GCC' and
707 other mirror sites for Linux-based GNU systems.
710 The ARM2 or ARM3 processor running RISC iX, Acorn's port of BSD
711 Unix. If you are running a version of RISC iX prior to 1.2 then
712 you must specify the version number during configuration. Note
713 that the assembler shipped with RISC iX does not support stabs
714 debugging information; a new version of the assembler, with stabs
715 support included, is now available from Acorn and via ftp
716 `ftp.acorn.com:/pub/riscix/as+xterm.tar.Z'. To enable stabs
717 debugging, pass `--with-gnu-as' to configure.
719 You will need to install GNU `sed' before you can run configure.
722 AMD Am29k-family processors. These are normally used in embedded
723 applications. There are no standard Unix configurations. This
724 configuration corresponds to AMD's standard calling sequence and
725 binary interface and is compatible with other 29k tools.
727 You may need to make a variant of the file `a29k.h' for your
728 particular configuration.
731 AMD Am29050 used in a system running a variant of BSD Unix.
734 DECstations can support three different personalities: Ultrix, DEC
735 OSF/1, and OSF/rose. To configure GCC for these platforms use the
736 following configurations:
739 Ultrix configuration.
742 Dec's version of OSF/1.
745 Open Software Foundation reference port of OSF/1 which uses
746 the OSF/rose object file format instead of ECOFF. Normally,
747 you would not select this configuration.
749 The MIPS C compiler needs to be told to increase its table size
750 for switch statements with the `-Wf,-XNg1500' option in order to
751 compile `cp/parse.c'. If you use the `-O2' optimization option,
752 you also need to use `-Olimit 3000'. Both of these options are
753 automatically generated in the `Makefile' that the shell script
754 `configure' builds. If you override the `CC' make variable and
755 use the MIPS compilers, you may need to add `-Wf,-XNg1500 -Olimit
759 The Elxsi's C compiler has known limitations that prevent it from
760 compiling GNU C. Please contact `mrs@cygnus.com' for more details.
763 A port to the AT&T DSP1610 family of processors.
766 Hitachi H8/300 series of processors.
768 The calling convention and structure layout has changed in release
769 2.6. All code must be recompiled. The calling convention now
770 passes the first three arguments in function calls in registers.
771 Structures are no longer a multiple of 2 bytes.
774 There are several variants of the HP-PA processor which run a
775 variety of operating systems. GNU CC must be configured to use
776 the correct processor type and operating system, or GNU CC will
777 not function correctly. The easiest way to handle this problem is
778 to *not* specify a target when configuring GNU CC, the `configure'
779 script will try to automatically determine the right processor
780 type and operating system.
782 `-g' does not work on HP-UX, since that system uses a peculiar
783 debugging format which GNU CC does not know about. However, `-g'
784 will work if you also use GAS and GDB in conjunction with GCC. We
785 highly recommend using GAS for all HP-PA configurations.
787 You should be using GAS-2.6 (or later) along with GDB-4.16 (or
788 later). These can be retrieved from all the traditional GNU ftp
791 GAS will need to be installed into a directory before `/bin',
792 `/usr/bin', and `/usr/ccs/bin' in your search path. You should
793 install GAS before you build GNU CC.
795 To enable debugging, you must configure GNU CC with the
796 `--with-gnu-as' option before building.
799 This port is very preliminary and has many known bugs. We hope to
800 have a higher-quality port for this machine soon.
802 `i386-*-linux-gnuoldld'
803 Use this configuration to generate `a.out' binaries on Linux-based
804 GNU systems if you do not have gas/binutils version 2.5.2 or later
805 installed. This is an obsolete configuration.
807 `i386-*-linux-gnuaout'
808 Use this configuration to generate `a.out' binaries on Linux-based
809 GNU systems. This configuration is being superseded. You must use
810 gas/binutils version 2.5.2 or later.
813 Use this configuration to generate ELF binaries on Linux-based GNU
814 systems. You must use gas/binutils version 2.5.2 or later.
817 Compilation with RCC is recommended. Also, it may be a good idea
818 to link with GNU malloc instead of the malloc that comes with the
822 Use this configuration for SCO release 3.2 version 4.
825 Use this for the SCO OpenServer Release family including 5.0.0,
826 5.0.2, 5.0.4, Internet FastStart 1.0, and Internet FastStart 1.1.
828 GNU CC can generate ELF binaries (if you specify `-melf') or COFF
829 binaries (the default). If you are going to build your compiler
830 in ELF mode (once you have bootstrapped the first stage compiler)
831 you *must* specify `-melf' as part of `CC', *not* `CFLAGS', for
832 example as `CC="stage1/xgcc -melf -Bstage1/" '. If you do not do
833 this, the bootstrap will generate incorrect versions of `libgcc.a'.
835 You must have TLS597 (from ftp.sco.com/TLS) installed for ELF
836 binaries to work correctly. Note that Open Server 5.0.2 *does*
837 need TLS597 installed.
839 *NOTE:* You must follow the instructions about invoking `make
840 bootstrap' because the native OpenServer compiler builds a
841 `cc1plus' that will not correctly parse many valid C++ programs.
842 You must do a `make bootstrap' if you are building with the native
846 It may be a good idea to link with GNU malloc instead of the
847 malloc that comes with the system.
849 In ISC version 4.1, `sed' core dumps when building `deduced.h'.
850 Use the version of `sed' from version 4.0.
853 It may be good idea to link with GNU malloc instead of the malloc
854 that comes with the system.
857 You need to use GAS version 2.1 or later, and LD from GNU binutils
858 version 2.2 or later.
861 Go to the Berkeley universe before compiling.
864 Sequent DYNIX/ptx 1.x.
867 Sequent DYNIX/ptx 2.x.
870 You may find that you need another version of GNU CC to begin
871 bootstrapping with, since the current version when built with the
872 system's own compiler seems to get an infinite loop compiling part
873 of `libgcc2.c'. GNU CC version 2 compiled with GNU CC (any
874 version) seems not to have this problem.
876 See *Note Sun Install::, for information on installing GNU CC on
879 `i[345]86-*-winnt3.5'
880 This version requires a GAS that has not yet been released. Until
881 it is, you can get a prebuilt binary version via anonymous ftp from
882 `cs.washington.edu:pub/gnat' or `cs.nyu.edu:pub/gnat'. You must
883 also use the Microsoft header files from the Windows NT 3.5 SDK.
884 Find these on the CDROM in the `/mstools/h' directory dated
885 9/4/94. You must use a fixed version of Microsoft linker made
886 especially for NT 3.5, which is also is available on the NT 3.5
887 SDK CDROM. If you do not have this linker, can you also use the
888 linker from Visual C/C++ 1.0 or 2.0.
890 Installing GNU CC for NT builds a wrapper linker, called `ld.exe',
891 which mimics the behaviour of Unix `ld' in the specification of
892 libraries (`-L' and `-l'). `ld.exe' looks for both Unix and
893 Microsoft named libraries. For example, if you specify `-lfoo',
894 `ld.exe' will look first for `libfoo.a' and then for `foo.lib'.
896 You may install GNU CC for Windows NT in one of two ways,
897 depending on whether or not you have a Unix-like shell and various
900 1. If you do not have a Unix-like shell and few Unix-like
901 utilities, you will use a DOS style batch script called
902 `configure.bat'. Invoke it as `configure winnt' from an
903 MSDOS console window or from the program manager dialog box.
904 `configure.bat' assumes you have already installed and have
905 in your path a Unix-like `sed' program which is used to
906 create a working `Makefile' from `Makefile.in'.
908 `Makefile' uses the Microsoft Nmake program maintenance
909 utility and the Visual C/C++ V8.00 compiler to build GNU CC.
910 You need only have the utilities `sed' and `touch' to use
911 this installation method, which only automatically builds the
912 compiler itself. You must then examine what `fixinc.winnt'
913 does, edit the header files by hand and build `libgcc.a'
916 2. The second type of installation assumes you are running a
917 Unix-like shell, have a complete suite of Unix-like utilities
918 in your path, and have a previous version of GNU CC already
919 installed, either through building it via the above
920 installation method or acquiring a pre-built binary. In this
921 case, use the `configure' script in the normal fashion.
924 This is the Paragon. If you have version 1.0 of the operating
925 system, you need to take special steps to build GNU CC due to
926 peculiarities of the system. Newer system versions have no
927 problem. See the section `Installation Problems' in the GNU CC
931 LynxOS 2.2 and earlier comes with GNU CC 1.x already installed as
932 `/bin/gcc'. You should compile with this instead of `/bin/cc'.
933 You can tell GNU CC to use the GNU assembler and linker, by
934 specifying `--with-gnu-as --with-gnu-ld' when configuring. These
935 will produce COFF format object files and executables; otherwise
936 GNU CC will use the installed tools, which produce `a.out' format
940 Mitsubishi M32R processor. This configuration is intended for
944 HP 9000 series 200 running BSD. Note that the C compiler that
945 comes with this system cannot compile GNU CC; contact
946 `law@cs.utah.edu' to get binaries of GNU CC for bootstrapping.
949 Altos 3068. You must use the GNU assembler, linker and debugger.
950 Also, you must fix a kernel bug. Details in the file
954 Apple Macintosh running A/UX. You may configure GCC to use
955 either the system assembler and linker or the GNU assembler and
956 linker. You should use the GNU configuration if you can,
957 especially if you also want to use GNU C++. You enabled that
958 configuration with + the `--with-gnu-as' and `--with-gnu-ld'
959 options to `configure'.
961 Note the C compiler that comes with this system cannot compile GNU
962 CC. You can fine binaries of GNU CC for bootstrapping on
963 `jagubox.gsfc.nasa.gov'. You will also a patched version of
964 `/bin/ld' there that raises some of the arbitrary limits found in
968 AT&T 3b1, a.k.a. 7300 PC. Special procedures are needed to
969 compile GNU CC with this machine's standard C compiler, due to
970 bugs in that compiler. You can bootstrap it more easily with
971 previous versions of GNU CC if you have them.
973 Installing GNU CC on the 3b1 is difficult if you do not already
974 have GNU CC running, due to bugs in the installed C compiler.
975 However, the following procedure might work. We are unable to
978 1. Comment out the `#include "config.h"' line near the start of
979 `cccp.c' and do `make cpp'. This makes a preliminary version
982 2. Save the old `/lib/cpp' and copy the preliminary GNU cpp to
985 3. Undo your change in `cccp.c', or reinstall the original
986 version, and do `make cpp' again.
988 4. Copy this final version of GNU cpp into `/lib/cpp'.
990 5. Replace every occurrence of `obstack_free' in the file
991 `tree.c' with `_obstack_free'.
993 6. Run `make' to get the first-stage GNU CC.
995 7. Reinstall the original version of `/lib/cpp'.
997 8. Now you can compile GNU CC with itself and install it in the
1001 Bull DPX/2 series 200 and 300 with BOS-2.00.45 up to BOS-2.01. GNU
1002 CC works either with native assembler or GNU assembler. You can use
1003 GNU assembler with native coff generation by providing
1004 `--with-gnu-as' to the configure script or use GNU assembler with
1005 dbx-in-coff encapsulation by providing `--with-gnu-as --stabs'.
1006 For any problem with native assembler or for availability of the
1007 DPX/2 port of GAS, contact `F.Pierresteguy@frcl.bull.fr'.
1010 Use `configure unos' for building on Unos.
1012 The Unos assembler is named `casm' instead of `as'. For some
1013 strange reason linking `/bin/as' to `/bin/casm' changes the
1014 behavior, and does not work. So, when installing GNU CC, you
1015 should install the following script as `as' in the subdirectory
1016 where the passes of GCC are installed:
1021 The default Unos library is named `libunos.a' instead of `libc.a'.
1022 To allow GNU CC to function, either change all references to
1023 `-lc' in `gcc.c' to `-lunos' or link `/lib/libc.a' to
1026 When compiling GNU CC with the standard compiler, to overcome bugs
1027 in the support of `alloca', do not use `-O' when making stage 2.
1028 Then use the stage 2 compiler with `-O' to make the stage 3
1029 compiler. This compiler will have the same characteristics as the
1030 usual stage 2 compiler on other systems. Use it to make a stage 4
1031 compiler and compare that with stage 3 to verify proper
1034 (Perhaps simply defining `ALLOCA' in `x-crds' as described in the
1035 comments there will make the above paragraph superfluous. Please
1036 inform us of whether this works.)
1038 Unos uses memory segmentation instead of demand paging, so you
1039 will need a lot of memory. 5 Mb is barely enough if no other
1040 tasks are running. If linking `cc1' fails, try putting the object
1041 files into a library and linking from that library.
1044 HP 9000 series 300 or 400 running HP-UX. HP-UX version 8.0 has a
1045 bug in the assembler that prevents compilation of GNU CC. To fix
1046 it, get patch PHCO_4484 from HP.
1048 In addition, if you wish to use gas `--with-gnu-as' you must use
1049 gas version 2.1 or later, and you must use the GNU linker version
1050 2.1 or later. Earlier versions of gas relied upon a program which
1051 converted the gas output into the native HP/UX format, but that
1052 program has not been kept up to date. gdb does not understand
1053 that native HP/UX format, so you must use gas if you wish to use
1057 Sun 3. We do not provide a configuration file to use the Sun FPA
1058 by default, because programs that establish signal handlers for
1059 floating point traps inherently cannot work with the FPA.
1061 See *Note Sun Install::, for information on installing GNU CC on
1065 Motorola m88k running the AT&T/Unisoft/Motorola V.3 reference port.
1066 These systems tend to use the Green Hills C, revision 1.8.5, as the
1067 standard C compiler. There are apparently bugs in this compiler
1068 that result in object files differences between stage 2 and stage
1069 3. If this happens, make the stage 4 compiler and compare it to
1070 the stage 3 compiler. If the stage 3 and stage 4 object files are
1071 identical, this suggests you encountered a problem with the
1072 standard C compiler; the stage 3 and 4 compilers may be usable.
1074 It is best, however, to use an older version of GNU CC for
1075 bootstrapping if you have one.
1078 Motorola m88k running DG/UX. To build 88open BCS native or cross
1079 compilers on DG/UX, specify the configuration name as
1080 `m88k-*-dguxbcs' and build in the 88open BCS software development
1081 environment. To build ELF native or cross compilers on DG/UX,
1082 specify `m88k-*-dgux' and build in the DG/UX ELF development
1083 environment. You set the software development environment by
1084 issuing `sde-target' command and specifying either `m88kbcs' or
1085 `m88kdguxelf' as the operand.
1087 If you do not specify a configuration name, `configure' guesses the
1088 configuration based on the current software development
1091 `m88k-tektronix-sysv3'
1092 Tektronix XD88 running UTekV 3.2e. Do not turn on optimization
1093 while building stage1 if you bootstrap with the buggy Green Hills
1094 compiler. Also, The bundled LAI System V NFS is buggy so if you
1095 build in an NFS mounted directory, start from a fresh reboot, or
1096 avoid NFS all together. Otherwise you may have trouble getting
1097 clean comparisons between stages.
1100 MIPS machines running the MIPS operating system in BSD mode. It's
1101 possible that some old versions of the system lack the functions
1102 `memcpy', `memcmp', and `memset'. If your system lacks these, you
1103 must remove or undo the definition of `TARGET_MEM_FUNCTIONS' in
1106 The MIPS C compiler needs to be told to increase its table size
1107 for switch statements with the `-Wf,-XNg1500' option in order to
1108 compile `cp/parse.c'. If you use the `-O2' optimization option,
1109 you also need to use `-Olimit 3000'. Both of these options are
1110 automatically generated in the `Makefile' that the shell script
1111 `configure' builds. If you override the `CC' make variable and
1112 use the MIPS compilers, you may need to add `-Wf,-XNg1500 -Olimit
1116 The MIPS C compiler needs to be told to increase its table size
1117 for switch statements with the `-Wf,-XNg1500' option in order to
1118 compile `cp/parse.c'. If you use the `-O2' optimization option,
1119 you also need to use `-Olimit 3000'. Both of these options are
1120 automatically generated in the `Makefile' that the shell script
1121 `configure' builds. If you override the `CC' make variable and
1122 use the MIPS compilers, you may need to add `-Wf,-XNg1500 -Olimit
1125 MIPS computers running RISC-OS can support four different
1126 personalities: default, BSD 4.3, System V.3, and System V.4 (older
1127 versions of RISC-OS don't support V.4). To configure GCC for
1128 these platforms use the following configurations:
1130 `mips-mips-riscos`rev''
1131 Default configuration for RISC-OS, revision `rev'.
1133 `mips-mips-riscos`rev'bsd'
1134 BSD 4.3 configuration for RISC-OS, revision `rev'.
1136 `mips-mips-riscos`rev'sysv4'
1137 System V.4 configuration for RISC-OS, revision `rev'.
1139 `mips-mips-riscos`rev'sysv'
1140 System V.3 configuration for RISC-OS, revision `rev'.
1142 The revision `rev' mentioned above is the revision of RISC-OS to
1143 use. You must reconfigure GCC when going from a RISC-OS revision
1144 4 to RISC-OS revision 5. This has the effect of avoiding a linker
1148 In order to compile GCC on an SGI running IRIX 4, the "c.hdr.lib"
1149 option must be installed from the CD-ROM supplied from Silicon
1150 Graphics. This is found on the 2nd CD in release 4.0.1.
1152 In order to compile GCC on an SGI running IRIX 5, the
1153 "compiler_dev.hdr" subsystem must be installed from the IDO CD-ROM
1154 supplied by Silicon Graphics.
1156 `make compare' may fail on version 5 of IRIX unless you add
1157 `-save-temps' to `CFLAGS'. On these systems, the name of the
1158 assembler input file is stored in the object file, and that makes
1159 comparison fail if it differs between the `stage1' and `stage2'
1160 compilations. The option `-save-temps' forces a fixed name to be
1161 used for the assembler input file, instead of a randomly chosen
1162 name in `/tmp'. Do not add `-save-temps' unless the comparisons
1163 fail without that option. If you do you `-save-temps', you will
1164 have to manually delete the `.i' and `.s' files after each series
1167 The MIPS C compiler needs to be told to increase its table size
1168 for switch statements with the `-Wf,-XNg1500' option in order to
1169 compile `cp/parse.c'. If you use the `-O2' optimization option,
1170 you also need to use `-Olimit 3000'. Both of these options are
1171 automatically generated in the `Makefile' that the shell script
1172 `configure' builds. If you override the `CC' make variable and
1173 use the MIPS compilers, you may need to add `-Wf,-XNg1500 -Olimit
1176 On Irix version 4.0.5F, and perhaps on some other versions as well,
1177 there is an assembler bug that reorders instructions incorrectly.
1178 To work around it, specify the target configuration
1179 `mips-sgi-irix4loser'. This configuration inhibits assembler
1182 In a compiler configured with target `mips-sgi-irix4', you can turn
1183 off assembler optimization by using the `-noasmopt' option. This
1184 compiler option passes the option `-O0' to the assembler, to
1187 The `-noasmopt' option can be useful for testing whether a problem
1188 is due to erroneous assembler reordering. Even if a problem does
1189 not go away with `-noasmopt', it may still be due to assembler
1190 reordering--perhaps GNU CC itself was miscompiled as a result.
1192 To enable debugging under Irix 5, you must use GNU as 2.5 or later,
1193 and use the `--with-gnu-as' configure option when configuring gcc.
1194 GNU as is distributed as part of the binutils package.
1197 Sony MIPS NEWS. This works in NEWSOS 5.0.1, but not in 5.0.2
1198 (which uses ELF instead of COFF). Support for 5.0.2 will probably
1199 be provided soon by volunteers. In particular, the linker does
1200 not like the code generated by GCC when shared libraries are
1204 Encore ns32000 system. Encore systems are supported only under
1208 National Semiconductor ns32000 system. Genix has bugs in `alloca'
1209 and `malloc'; you must get the compiled versions of these from GNU
1213 Go to the Berkeley universe before compiling.
1216 UTEK ns32000 system ("merlin"). The C compiler that comes with
1217 this system cannot compile GNU CC; contact `tektronix!reed!mason'
1218 to get binaries of GNU CC for bootstrapping.
1222 The only operating systems supported for the IBM RT PC are AOS and
1223 MACH. GNU CC does not support AIX running on the RT. We
1224 recommend you compile GNU CC with an earlier version of itself; if
1225 you compile GNU CC with `hc', the Metaware compiler, it will work,
1226 but you will get mismatches between the stage 2 and stage 3
1227 compilers in various files. These errors are minor differences in
1228 some floating-point constants and can be safely ignored; the stage
1229 3 compiler is correct.
1233 Various early versions of each release of the IBM XLC compiler
1234 will not bootstrap GNU CC. Symptoms include differences between
1235 the stage2 and stage3 object files, and errors when compiling
1236 `libgcc.a' or `enquire'. Known problematic releases include:
1237 xlc-1.2.1.8, xlc-1.3.0.0 (distributed with AIX 3.2.5), and
1238 xlc-1.3.0.19. Both xlc-1.2.1.28 and xlc-1.3.0.24 (PTF 432238) are
1239 known to produce working versions of GNU CC, but most other recent
1240 releases correctly bootstrap GNU CC. Also, releases of AIX prior
1241 to AIX 3.2.4 include a version of the IBM assembler which does not
1242 accept debugging directives: assembler updates are available as
1243 PTFs. Also, if you are using AIX 3.2.5 or greater and the GNU
1244 assembler, you must have a version modified after October 16th,
1245 1995 in order for the GNU C compiler to build. See the file
1246 `README.RS6000' for more details on of these problems.
1248 GNU CC does not yet support the 64-bit PowerPC instructions.
1250 Objective C does not work on this architecture because it makes
1251 assumptions that are incompatible with the calling conventions.
1253 AIX on the RS/6000 provides support (NLS) for environments outside
1254 of the United States. Compilers and assemblers use NLS to support
1255 locale-specific representations of various objects including
1256 floating-point numbers ("." vs "," for separating decimal
1257 fractions). There have been problems reported where the library
1258 linked with GNU CC does not produce the same floating-point
1259 formats that the assembler accepts. If you have this problem, set
1260 the LANG environment variable to "C" or "En_US".
1262 Due to changes in the way that GNU CC invokes the binder (linker)
1263 for AIX 4.1, you may now receive warnings of duplicate symbols
1264 from the link step that were not reported before. The assembly
1265 files generated by GNU CC for AIX have always included multiple
1266 symbol definitions for certain global variable and function
1267 declarations in the original program. The warnings should not
1268 prevent the linker from producing a correct library or runnable
1271 By default, AIX 4.1 produces code that can be used on either Power
1272 or PowerPC processors.
1274 You can specify a default version for the `-mcpu='CPU_TYPE switch
1275 by using the configure option `--with-cpu-'CPU_TYPE.
1279 PowerPC system in big endian mode, running System V.4.
1281 You can specify a default version for the `-mcpu='CPU_TYPE switch
1282 by using the configure option `--with-cpu-'CPU_TYPE.
1284 `powerpc-*-linux-gnu'
1285 PowerPC system in big endian mode, running the Linux-based GNU
1288 You can specify a default version for the `-mcpu='CPU_TYPE switch
1289 by using the configure option `--with-cpu-'CPU_TYPE.
1292 Embedded PowerPC system in big endian mode with -mcall-aix
1293 selected as the default.
1295 You can specify a default version for the `-mcpu='CPU_TYPE switch
1296 by using the configure option `--with-cpu-'CPU_TYPE.
1299 Embedded PowerPC system in big endian mode for use in running
1300 under the PSIM simulator.
1302 You can specify a default version for the `-mcpu='CPU_TYPE switch
1303 by using the configure option `--with-cpu-'CPU_TYPE.
1306 Embedded PowerPC system in big endian mode.
1308 You can specify a default version for the `-mcpu='CPU_TYPE switch
1309 by using the configure option `--with-cpu-'CPU_TYPE.
1313 PowerPC system in little endian mode, running System V.4.
1315 You can specify a default version for the `-mcpu='CPU_TYPE switch
1316 by using the configure option `--with-cpu-'CPU_TYPE.
1318 `powerpcle-*-solaris2*'
1319 PowerPC system in little endian mode, running Solaris 2.5.1 or
1322 You can specify a default version for the `-mcpu='CPU_TYPE switch
1323 by using the configure option `--with-cpu-'CPU_TYPE. Beta
1324 versions of the Sun 4.0 compiler do not seem to be able to build
1325 GNU CC correctly. There are also problems with the host assembler
1326 and linker that are fixed by using the GNU versions of these tools.
1328 `powerpcle-*-eabisim'
1329 Embedded PowerPC system in little endian mode for use in running
1330 under the PSIM simulator.
1333 Embedded PowerPC system in little endian mode.
1335 You can specify a default version for the `-mcpu='CPU_TYPE switch
1336 by using the configure option `--with-cpu-'CPU_TYPE.
1340 PowerPC system in little endian mode running Windows NT.
1342 You can specify a default version for the `-mcpu='CPU_TYPE switch
1343 by using the configure option `--with-cpu-'CPU_TYPE.
1346 Don't try compiling with Vax C (`vcc'). It produces incorrect code
1347 in some cases (for example, when `alloca' is used).
1349 Meanwhile, compiling `cp/parse.c' with pcc does not work because of
1350 an internal table size limitation in that compiler. To avoid this
1351 problem, compile just the GNU C compiler first, and use it to
1352 recompile building all the languages that you want to run.
1355 See *Note Sun Install::, for information on installing GNU CC on
1359 See *Note VMS Install::, for details on how to install GNU CC on
1363 These computers are also known as the 3b2, 3b5, 3b20 and other
1364 similar names. (However, the 3b1 is actually a 68000; see *Note
1367 Don't use `-g' when compiling with the system's compiler. The
1368 system's linker seems to be unable to handle such a large program
1369 with debugging information.
1371 The system's compiler runs out of capacity when compiling `stmt.c'
1372 in GNU CC. You can work around this by building `cpp' in GNU CC
1373 first, then use that instead of the system's preprocessor with the
1374 system's C compiler to compile `stmt.c'. Here is how:
1376 mv /lib/cpp /lib/cpp.att
1378 echo '/lib/cpp.gnu -traditional ${1+"$@"}' > /lib/cpp
1381 The system's compiler produces bad code for some of the GNU CC
1382 optimization files. So you must build the stage 2 compiler without
1383 optimization. Then build a stage 3 compiler with optimization.
1384 That executable should work. Here are the necessary commands:
1386 make LANGUAGES=c CC=stage1/xgcc CFLAGS="-Bstage1/ -g"
1388 make CC=stage2/xgcc CFLAGS="-Bstage2/ -g -O"
1390 You may need to raise the ULIMIT setting to build a C++ compiler,
1391 as the file `cc1plus' is larger than one megabyte.
1393 Compilation in a Separate Directory
1394 ===================================
1396 If you wish to build the object files and executables in a directory
1397 other than the one containing the source files, here is what you must
1400 1. Make sure you have a version of Make that supports the `VPATH'
1401 feature. (GNU Make supports it, as do Make versions on most BSD
1404 2. If you have ever run `configure' in the source directory, you must
1405 undo the configuration. Do this by running:
1409 3. Go to the directory in which you want to build the compiler before
1410 running `configure':
1415 On systems that do not support symbolic links, this directory must
1416 be on the same file system as the source code directory.
1418 4. Specify where to find `configure' when you run it:
1420 ../gcc/configure ...
1422 This also tells `configure' where to find the compiler sources;
1423 `configure' takes the directory from the file name that was used to
1424 invoke it. But if you want to be sure, you can specify the source
1425 directory with the `--srcdir' option, like this:
1427 ../gcc/configure --srcdir=../gcc OTHER OPTIONS
1429 The directory you specify with `--srcdir' need not be the same as
1430 the one that `configure' is found in.
1432 Now, you can run `make' in that directory. You need not repeat the
1433 configuration steps shown above, when ordinary source files change. You
1434 must, however, run `configure' again when the configuration files
1435 change, if your system does not support symbolic links.
1437 Building and Installing a Cross-Compiler
1438 ========================================
1440 GNU CC can function as a cross-compiler for many machines, but not
1443 * Cross-compilers for the Mips as target using the Mips assembler
1444 currently do not work, because the auxiliary programs
1445 `mips-tdump.c' and `mips-tfile.c' can't be compiled on anything
1446 but a Mips. It does work to cross compile for a Mips if you use
1447 the GNU assembler and linker.
1449 * Cross-compilers between machines with different floating point
1450 formats have not all been made to work. GNU CC now has a floating
1451 point emulator with which these can work, but each target machine
1452 description needs to be updated to take advantage of it.
1454 * Cross-compilation between machines of different word sizes is
1455 somewhat problematic and sometimes does not work.
1457 Since GNU CC generates assembler code, you probably need a
1458 cross-assembler that GNU CC can run, in order to produce object files.
1459 If you want to link on other than the target machine, you need a
1460 cross-linker as well. You also need header files and libraries suitable
1461 for the target machine that you can install on the host machine.
1463 Steps of Cross-Compilation
1464 --------------------------
1466 To compile and run a program using a cross-compiler involves several
1469 * Run the cross-compiler on the host machine to produce assembler
1470 files for the target machine. This requires header files for the
1473 * Assemble the files produced by the cross-compiler. You can do this
1474 either with an assembler on the target machine, or with a
1475 cross-assembler on the host machine.
1477 * Link those files to make an executable. You can do this either
1478 with a linker on the target machine, or with a cross-linker on the
1479 host machine. Whichever machine you use, you need libraries and
1480 certain startup files (typically `crt....o') for the target
1483 It is most convenient to do all of these steps on the same host
1484 machine, since then you can do it all with a single invocation of GNU
1485 CC. This requires a suitable cross-assembler and cross-linker. For
1486 some targets, the GNU assembler and linker are available.
1488 Configuring a Cross-Compiler
1489 ----------------------------
1491 To build GNU CC as a cross-compiler, you start out by running
1492 `configure'. Use the `--target=TARGET' to specify the target type. If
1493 `configure' was unable to correctly identify the system you are running
1494 on, also specify the `--build=BUILD' option. For example, here is how
1495 to configure for a cross-compiler that produces code for an HP 68030
1496 system running BSD on a system that `configure' can correctly identify:
1498 ./configure --target=m68k-hp-bsd4.3
1500 Tools and Libraries for a Cross-Compiler
1501 ----------------------------------------
1503 If you have a cross-assembler and cross-linker available, you should
1504 install them now. Put them in the directory `/usr/local/TARGET/bin'.
1505 Here is a table of the tools you should put in this directory:
1508 This should be the cross-assembler.
1511 This should be the cross-linker.
1514 This should be the cross-archiver: a program which can manipulate
1515 archive files (linker libraries) in the target machine's format.
1518 This should be a program to construct a symbol table in an archive
1521 The installation of GNU CC will find these programs in that
1522 directory, and copy or link them to the proper place to for the
1523 cross-compiler to find them when run later.
1525 The easiest way to provide these files is to build the Binutils
1526 package and GAS. Configure them with the same `--host' and `--target'
1527 options that you use for configuring GNU CC, then build and install
1528 them. They install their executables automatically into the proper
1529 directory. Alas, they do not support all the targets that GNU CC
1532 If you want to install libraries to use with the cross-compiler,
1533 such as a standard C library, put them in the directory
1534 `/usr/local/TARGET/lib'; installation of GNU CC copies all the files in
1535 that subdirectory into the proper place for GNU CC to find them and
1536 link with them. Here's an example of copying some libraries from a
1540 lcd /usr/local/TARGET/lib
1548 The precise set of libraries you'll need, and their locations on the
1549 target machine, vary depending on its operating system.
1551 Many targets require "start files" such as `crt0.o' and `crtn.o'
1552 which are linked into each executable; these too should be placed in
1553 `/usr/local/TARGET/lib'. There may be several alternatives for
1554 `crt0.o', for use with profiling or other compilation options. Check
1555 your target's definition of `STARTFILE_SPEC' to find out what start
1556 files it uses. Here's an example of copying these files from a target
1560 lcd /usr/local/TARGET/lib
1568 `libgcc.a' and Cross-Compilers
1569 ------------------------------
1571 Code compiled by GNU CC uses certain runtime support functions
1572 implicitly. Some of these functions can be compiled successfully with
1573 GNU CC itself, but a few cannot be. These problem functions are in the
1574 source file `libgcc1.c'; the library made from them is called
1577 When you build a native compiler, these functions are compiled with
1578 some other compiler-the one that you use for bootstrapping GNU CC.
1579 Presumably it knows how to open code these operations, or else knows how
1580 to call the run-time emulation facilities that the machine comes with.
1581 But this approach doesn't work for building a cross-compiler. The
1582 compiler that you use for building knows about the host system, not the
1585 So, when you build a cross-compiler you have to supply a suitable
1586 library `libgcc1.a' that does the job it is expected to do.
1588 To compile `libgcc1.c' with the cross-compiler itself does not work.
1589 The functions in this file are supposed to implement arithmetic
1590 operations that GNU CC does not know how to open code for your target
1591 machine. If these functions are compiled with GNU CC itself, they will
1592 compile into infinite recursion.
1594 On any given target, most of these functions are not needed. If GNU
1595 CC can open code an arithmetic operation, it will not call these
1596 functions to perform the operation. It is possible that on your target
1597 machine, none of these functions is needed. If so, you can supply an
1598 empty library as `libgcc1.a'.
1600 Many targets need library support only for multiplication and
1601 division. If you are linking with a library that contains functions for
1602 multiplication and division, you can tell GNU CC to call them directly
1603 by defining the macros `MULSI3_LIBCALL', and the like. These macros
1604 need to be defined in the target description macro file. For some
1605 targets, they are defined already. This may be sufficient to avoid the
1606 need for libgcc1.a; if so, you can supply an empty library.
1608 Some targets do not have floating point instructions; they need other
1609 functions in `libgcc1.a', which do floating arithmetic. Recent
1610 versions of GNU CC have a file which emulates floating point. With a
1611 certain amount of work, you should be able to construct a floating
1612 point emulator that can be used as `libgcc1.a'. Perhaps future
1613 versions will contain code to do this automatically and conveniently.
1614 That depends on whether someone wants to implement it.
1616 Some embedded targets come with all the necessary `libgcc1.a'
1617 routines written in C or assembler. These targets build `libgcc1.a'
1618 automatically and you do not need to do anything special for them.
1619 Other embedded targets do not need any `libgcc1.a' routines since all
1620 the necessary operations are supported by the hardware.
1622 If your target system has another C compiler, you can configure GNU
1623 CC as a native compiler on that machine, build just `libgcc1.a' with
1624 `make libgcc1.a' on that machine, and use the resulting file with the
1625 cross-compiler. To do this, execute the following on the target
1629 ./configure --host=sparc --target=sun3
1632 And then this on the host machine:
1640 Another way to provide the functions you need in `libgcc1.a' is to
1641 define the appropriate `perform_...' macros for those functions. If
1642 these definitions do not use the C arithmetic operators that they are
1643 meant to implement, you should be able to compile them with the
1644 cross-compiler you are building. (If these definitions already exist
1645 for your target file, then you are all set.)
1647 To build `libgcc1.a' using the perform macros, use
1648 `LIBGCC1=libgcc1.a OLDCC=./xgcc' when building the compiler.
1649 Otherwise, you should place your replacement library under the name
1650 `libgcc1.a' in the directory in which you will build the
1651 cross-compiler, before you run `make'.
1653 Cross-Compilers and Header Files
1654 --------------------------------
1656 If you are cross-compiling a standalone program or a program for an
1657 embedded system, then you may not need any header files except the few
1658 that are part of GNU CC (and those of your program). However, if you
1659 intend to link your program with a standard C library such as `libc.a',
1660 then you probably need to compile with the header files that go with
1661 the library you use.
1663 The GNU C compiler does not come with these files, because (1) they
1664 are system-specific, and (2) they belong in a C library, not in a
1667 If the GNU C library supports your target machine, then you can get
1668 the header files from there (assuming you actually use the GNU library
1669 when you link your program).
1671 If your target machine comes with a C compiler, it probably comes
1672 with suitable header files also. If you make these files accessible
1673 from the host machine, the cross-compiler can use them also.
1675 Otherwise, you're on your own in finding header files to use when
1678 When you have found suitable header files, put them in the directory
1679 `/usr/local/TARGET/include', before building the cross compiler. Then
1680 installation will run fixincludes properly and install the corrected
1681 versions of the header files where the compiler will use them.
1683 Provide the header files before you build the cross-compiler, because
1684 the build stage actually runs the cross-compiler to produce parts of
1685 `libgcc.a'. (These are the parts that *can* be compiled with GNU CC.)
1686 Some of them need suitable header files.
1688 Here's an example showing how to copy the header files from a target
1689 machine. On the target machine, do this:
1691 (cd /usr/include; tar cf - .) > tarfile
1693 Then, on the host machine, do this:
1696 lcd /usr/local/TARGET/include
1701 Actually Building the Cross-Compiler
1702 ------------------------------------
1704 Now you can proceed just as for compiling a single-machine compiler
1705 through the step of building stage 1. If you have not provided some
1706 sort of `libgcc1.a', then compilation will give up at the point where
1707 it needs that file, printing a suitable error message. If you do
1708 provide `libgcc1.a', then building the compiler will automatically
1709 compile and link a test program called `libgcc1-test'; if you get
1710 errors in the linking, it means that not all of the necessary routines
1711 in `libgcc1.a' are available.
1713 You must provide the header file `float.h'. One way to do this is
1714 to compile `enquire' and run it on your target machine. The job of
1715 `enquire' is to run on the target machine and figure out by experiment
1716 the nature of its floating point representation. `enquire' records its
1717 findings in the header file `float.h'. If you can't produce this file
1718 by running `enquire' on the target machine, then you will need to come
1719 up with a suitable `float.h' in some other way (or else, avoid using it
1722 Do not try to build stage 2 for a cross-compiler. It doesn't work to
1723 rebuild GNU CC as a cross-compiler using the cross-compiler, because
1724 that would produce a program that runs on the target machine, not on the
1725 host. For example, if you compile a 386-to-68030 cross-compiler with
1726 itself, the result will not be right either for the 386 (because it was
1727 compiled into 68030 code) or for the 68030 (because it was configured
1728 for a 386 as the host). If you want to compile GNU CC into 68030 code,
1729 whether you compile it on a 68030 or with a cross-compiler on a 386, you
1730 must specify a 68030 as the host when you configure it.
1732 To install the cross-compiler, use `make install', as usual.
1734 Installing GNU CC on the Sun
1735 ============================
1737 On Solaris (version 2.1), do not use the linker or other tools in
1738 `/usr/ucb' to build GNU CC. Use `/usr/ccs/bin'.
1740 Make sure the environment variable `FLOAT_OPTION' is not set when
1741 you compile `libgcc.a'. If this option were set to `f68881' when
1742 `libgcc.a' is compiled, the resulting code would demand to be linked
1743 with a special startup file and would not link properly without special
1746 There is a bug in `alloca' in certain versions of the Sun library.
1747 To avoid this bug, install the binaries of GNU CC that were compiled by
1748 GNU CC. They use `alloca' as a built-in function and never the one in
1751 Some versions of the Sun compiler crash when compiling GNU CC. The
1752 problem is a segmentation fault in cpp. This problem seems to be due to
1753 the bulk of data in the environment variables. You may be able to avoid
1754 it by using the following command to compile GNU CC with Sun CC:
1756 make CC="TERMCAP=x OBJS=x LIBFUNCS=x STAGESTUFF=x cc"
1758 SunOS 4.1.3 and 4.1.3_U1 have bugs that can cause intermittent core
1759 dumps when compiling GNU CC. A common symptom is an internal compiler
1760 error which does not recur if you run it again. To fix the problem,
1761 install Sun recommended patch 100726 (for SunOS 4.1.3) or 101508 (for
1762 SunOS 4.1.3_U1), or upgrade to a later SunOS release.
1764 Installing GNU CC on VMS
1765 ========================
1767 The VMS version of GNU CC is distributed in a backup saveset
1768 containing both source code and precompiled binaries.
1770 To install the `gcc' command so you can use the compiler easily, in
1771 the same manner as you use the VMS C compiler, you must install the VMS
1772 CLD file for GNU CC as follows:
1774 1. Define the VMS logical names `GNU_CC' and `GNU_CC_INCLUDE' to
1775 point to the directories where the GNU CC executables
1776 (`gcc-cpp.exe', `gcc-cc1.exe', etc.) and the C include files are
1777 kept respectively. This should be done with the commands:
1779 $ assign /system /translation=concealed -
1781 $ assign /system /translation=concealed -
1782 disk:[gcc.include.] gnu_cc_include
1784 with the appropriate disk and directory names. These commands can
1785 be placed in your system startup file so they will be executed
1786 whenever the machine is rebooted. You may, if you choose, do this
1787 via the `GCC_INSTALL.COM' script in the `[GCC]' directory.
1789 2. Install the `GCC' command with the command line:
1791 $ set command /table=sys$common:[syslib]dcltables -
1792 /output=sys$common:[syslib]dcltables gnu_cc:[000000]gcc
1793 $ install replace sys$common:[syslib]dcltables
1795 3. To install the help file, do the following:
1797 $ library/help sys$library:helplib.hlb gcc.hlp
1799 Now you can invoke the compiler with a command like `gcc /verbose
1800 file.c', which is equivalent to the command `gcc -v -c file.c' in
1803 If you wish to use GNU C++ you must first install GNU CC, and then
1804 perform the following steps:
1806 1. Define the VMS logical name `GNU_GXX_INCLUDE' to point to the
1807 directory where the preprocessor will search for the C++ header
1808 files. This can be done with the command:
1810 $ assign /system /translation=concealed -
1811 disk:[gcc.gxx_include.] gnu_gxx_include
1813 with the appropriate disk and directory name. If you are going to
1814 be using a C++ runtime library, this is where its install
1815 procedure will install its header files.
1817 2. Obtain the file `gcc-cc1plus.exe', and place this in the same
1818 directory that `gcc-cc1.exe' is kept.
1820 The GNU C++ compiler can be invoked with a command like `gcc /plus
1821 /verbose file.cc', which is equivalent to the command `g++ -v -c
1824 We try to put corresponding binaries and sources on the VMS
1825 distribution tape. But sometimes the binaries will be from an older
1826 version than the sources, because we don't always have time to update
1827 them. (Use the `/version' option to determine the version number of
1828 the binaries and compare it with the source file `version.c' to tell
1829 whether this is so.) In this case, you should use the binaries you get
1830 to recompile the sources. If you must recompile, here is how:
1832 1. Execute the command procedure `vmsconfig.com' to set up the files
1833 `tm.h', `config.h', `aux-output.c', and `md.', and to create files
1834 `tconfig.h' and `hconfig.h'. This procedure also creates several
1835 linker option files used by `make-cc1.com' and a data file used by
1840 2. Setup the logical names and command tables as defined above. In
1841 addition, define the VMS logical name `GNU_BISON' to point at the
1842 to the directories where the Bison executable is kept. This
1843 should be done with the command:
1845 $ assign /system /translation=concealed -
1846 disk:[bison.] gnu_bison
1848 You may, if you choose, use the `INSTALL_BISON.COM' script in the
1849 `[BISON]' directory.
1851 3. Install the `BISON' command with the command line:
1853 $ set command /table=sys$common:[syslib]dcltables -
1854 /output=sys$common:[syslib]dcltables -
1855 gnu_bison:[000000]bison
1856 $ install replace sys$common:[syslib]dcltables
1858 4. Type `@make-gcc' to recompile everything (alternatively, submit
1859 the file `make-gcc.com' to a batch queue). If you wish to build
1860 the GNU C++ compiler as well as the GNU CC compiler, you must
1861 first edit `make-gcc.com' and follow the instructions that appear
1864 5. In order to use GCC, you need a library of functions which GCC
1865 compiled code will call to perform certain tasks, and these
1866 functions are defined in the file `libgcc2.c'. To compile this
1867 you should use the command procedure `make-l2.com', which will
1868 generate the library `libgcc2.olb'. `libgcc2.olb' should be built
1869 using the compiler built from the same distribution that
1870 `libgcc2.c' came from, and `make-gcc.com' will automatically do
1871 all of this for you.
1873 To install the library, use the following commands:
1875 $ library gnu_cc:[000000]gcclib/delete=(new,eprintf)
1876 $ library gnu_cc:[000000]gcclib/delete=L_*
1877 $ library libgcc2/extract=*/output=libgcc2.obj
1878 $ library gnu_cc:[000000]gcclib libgcc2.obj
1880 The first command simply removes old modules that will be replaced
1881 with modules from `libgcc2' under different module names. The
1882 modules `new' and `eprintf' may not actually be present in your
1883 `gcclib.olb'--if the VMS librarian complains about those modules
1884 not being present, simply ignore the message and continue on with
1885 the next command. The second command removes the modules that
1886 came from the previous version of the library `libgcc2.c'.
1888 Whenever you update the compiler on your system, you should also
1889 update the library with the above procedure.
1891 6. You may wish to build GCC in such a way that no files are written
1892 to the directory where the source files reside. An example would
1893 be the when the source files are on a read-only disk. In these
1894 cases, execute the following DCL commands (substituting your
1897 $ assign dua0:[gcc.build_dir.]/translation=concealed, -
1898 dua1:[gcc.source_dir.]/translation=concealed gcc_build
1899 $ set default gcc_build:[000000]
1901 where the directory `dua1:[gcc.source_dir]' contains the source
1902 code, and the directory `dua0:[gcc.build_dir]' is meant to contain
1903 all of the generated object files and executables. Once you have
1904 done this, you can proceed building GCC as described above. (Keep
1905 in mind that `gcc_build' is a rooted logical name, and thus the
1906 device names in each element of the search list must be an actual
1907 physical device name rather than another rooted logical name).
1909 7. *If you are building GNU CC with a previous version of GNU CC, you
1910 also should check to see that you have the newest version of the
1911 assembler*. In particular, GNU CC version 2 treats global constant
1912 variables slightly differently from GNU CC version 1, and GAS
1913 version 1.38.1 does not have the patches required to work with GCC
1914 version 2. If you use GAS 1.38.1, then `extern const' variables
1915 will not have the read-only bit set, and the linker will generate
1916 warning messages about mismatched psect attributes for these
1917 variables. These warning messages are merely a nuisance, and can
1920 If you are compiling with a version of GNU CC older than 1.33,
1921 specify `/DEFINE=("inline=")' as an option in all the
1922 compilations. This requires editing all the `gcc' commands in
1923 `make-cc1.com'. (The older versions had problems supporting
1924 `inline'.) Once you have a working 1.33 or newer GNU CC, you can
1925 change this file back.
1927 8. If you want to build GNU CC with the VAX C compiler, you will need
1928 to make minor changes in `make-cccp.com' and `make-cc1.com' to
1929 choose alternate definitions of `CC', `CFLAGS', and `LIBS'. See
1930 comments in those files. However, you must also have a working
1931 version of the GNU assembler (GNU as, aka GAS) as it is used as
1932 the back-end for GNU CC to produce binary object modules and is
1933 not included in the GNU CC sources. GAS is also needed to compile
1934 `libgcc2' in order to build `gcclib' (see above); `make-l2.com'
1935 expects to be able to find it operational in
1936 `gnu_cc:[000000]gnu-as.exe'.
1938 To use GNU CC on VMS, you need the VMS driver programs `gcc.exe',
1939 `gcc.com', and `gcc.cld'. They are distributed with the VMS
1940 binaries (`gcc-vms') rather than the GNU CC sources. GAS is also
1941 included in `gcc-vms', as is Bison.
1943 Once you have successfully built GNU CC with VAX C, you should use
1944 the resulting compiler to rebuild itself. Before doing this, be
1945 sure to restore the `CC', `CFLAGS', and `LIBS' definitions in
1946 `make-cccp.com' and `make-cc1.com'. The second generation
1947 compiler will be able to take advantage of many optimizations that
1948 must be suppressed when building with other compilers.
1950 Under previous versions of GNU CC, the generated code would
1951 occasionally give strange results when linked with the sharable
1952 `VAXCRTL' library. Now this should work.
1954 Even with this version, however, GNU CC itself should not be linked
1955 with the sharable `VAXCRTL'. The version of `qsort' in `VAXCRTL' has a
1956 bug (known to be present in VMS versions V4.6 through V5.5) which
1957 causes the compiler to fail.
1959 The executables are generated by `make-cc1.com' and `make-cccp.com'
1960 use the object library version of `VAXCRTL' in order to make use of the
1961 `qsort' routine in `gcclib.olb'. If you wish to link the compiler
1962 executables with the shareable image version of `VAXCRTL', you should
1963 edit the file `tm.h' (created by `vmsconfig.com') to define the macro
1966 `QSORT_WORKAROUND' is always defined when GNU CC is compiled with
1967 VAX C, to avoid a problem in case `gcclib.olb' is not yet available.
1972 Many target systems do not have support in the assembler and linker
1973 for "constructors"--initialization functions to be called before the
1974 official "start" of `main'. On such systems, GNU CC uses a utility
1975 called `collect2' to arrange to call these functions at start time.
1977 The program `collect2' works by linking the program once and looking
1978 through the linker output file for symbols with particular names
1979 indicating they are constructor functions. If it finds any, it creates
1980 a new temporary `.c' file containing a table of them, compiles it, and
1981 links the program a second time including that file.
1983 The actual calls to the constructors are carried out by a subroutine
1984 called `__main', which is called (automatically) at the beginning of
1985 the body of `main' (provided `main' was compiled with GNU CC). Calling
1986 `__main' is necessary, even when compiling C code, to allow linking C
1987 and C++ object code together. (If you use `-nostdlib', you get an
1988 unresolved reference to `__main', since it's defined in the standard
1989 GCC library. Include `-lgcc' at the end of your compiler command line
1990 to resolve this reference.)
1992 The program `collect2' is installed as `ld' in the directory where
1993 the passes of the compiler are installed. When `collect2' needs to
1994 find the *real* `ld', it tries the following file names:
1996 * `real-ld' in the directories listed in the compiler's search
1999 * `real-ld' in the directories listed in the environment variable
2002 * The file specified in the `REAL_LD_FILE_NAME' configuration macro,
2005 * `ld' in the compiler's search directories, except that `collect2'
2006 will not execute itself recursively.
2010 "The compiler's search directories" means all the directories where
2011 `gcc' searches for passes of the compiler. This includes directories
2012 that you specify with `-B'.
2014 Cross-compilers search a little differently:
2016 * `real-ld' in the compiler's search directories.
2018 * `TARGET-real-ld' in `PATH'.
2020 * The file specified in the `REAL_LD_FILE_NAME' configuration macro,
2023 * `ld' in the compiler's search directories.
2025 * `TARGET-ld' in `PATH'.
2027 `collect2' explicitly avoids running `ld' using the file name under
2028 which `collect2' itself was invoked. In fact, it remembers up a list
2029 of such names--in case one copy of `collect2' finds another copy (or
2030 version) of `collect2' installed as `ld' in a second place in the
2033 `collect2' searches for the utilities `nm' and `strip' using the
2034 same algorithm as above for `ld'.
2036 Standard Header File Directories
2037 ================================
2039 `GCC_INCLUDE_DIR' means the same thing for native and cross. It is
2040 where GNU CC stores its private include files, and also where GNU CC
2041 stores the fixed include files. A cross compiled GNU CC runs
2042 `fixincludes' on the header files in `$(tooldir)/include'. (If the
2043 cross compilation header files need to be fixed, they must be installed
2044 before GNU CC is built. If the cross compilation header files are
2045 already suitable for ANSI C and GNU CC, nothing special need be done).
2047 `GPLUS_INCLUDE_DIR' means the same thing for native and cross. It
2048 is where `g++' looks first for header files. The C++ library installs
2049 only target independent header files in that directory.
2051 `LOCAL_INCLUDE_DIR' is used only for a native compiler. It is
2052 normally `/usr/local/include'. GNU CC searches this directory so that
2053 users can install header files in `/usr/local/include'.
2055 `CROSS_INCLUDE_DIR' is used only for a cross compiler. GNU CC
2056 doesn't install anything there.
2058 `TOOL_INCLUDE_DIR' is used for both native and cross compilers. It
2059 is the place for other packages to install header files that GNU CC will
2060 use. For a cross-compiler, this is the equivalent of `/usr/include'.
2061 When you build a cross-compiler, `fixincludes' processes any header
2062 files in this directory.