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GNU Info File | 1993-10-22 | 48.3 KB | 1,100 lines

This is Info file gcc.info, produced by Makeinfo-1.54 from the input file gcc.texi. This file documents the use and the internals of the GNU compiler. Published by the Free Software Foundation 675 Massachusetts Avenue Cambridge, MA 02139 USA Copyright (C) 1988, 1989, 1992, 1993 Free Software Foundation, Inc. Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided also that the sections entitled "GNU General Public License" and "Protect Your Freedom--Fight `Look And Feel'" are included exactly as in the original, and provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that the sections entitled "GNU General Public License" and "Protect Your Freedom--Fight `Look And Feel'", and this permission notice, may be included in translations approved by the Free Software Foundation instead of in the original English. File: gcc.info, Node: Installation, Next: C Extensions, Prev: Invoking GCC, Up: Top Installing GNU CC ***************** Here is the procedure for installing GNU CC on a Unix system. * Menu: * Other Dir:: Compiling in a separate directory (not where the source is). * Cross-Compiler:: Building and installing a cross-compiler. * PA Install:: See below for installation on the HP Precision Architecture. * Sun Install:: See below for installation on the Sun. * 3b1 Install:: See below for installation on the 3b1. * Unos Install:: See below for installation on Unos (from CRDS). * VMS Install:: See below for installation on VMS. * WE32K Install:: See below for installation on the 3b* aside from the 3b1. * MIPS Install:: See below for installation on the MIPS Architecture. * Collect2:: How `collect2' works; how it finds `ld'. * Header Dirs:: Understanding the standard header file directories. 1. If you have built GNU CC previously in the same directory for a different target machine, do `make distclean' to delete all files that might be invalid. One of the files this deletes is `Makefile'; if `make distclean' complains that `Makefile' does not exist, it probably means that the directory is already suitably clean. 2. On a System V release 4 system, make sure `/usr/bin' precedes `/usr/ucb' in `PATH'. The `cc' command in `/usr/ucb' uses libraries which have bugs. 3. Specify the host and target machine configurations. You do this by running the file `configure' with appropriate arguments. If you are building a compiler to produce code for the machine it runs on, specify just one machine type, with the `--target' option; the host type will default to be the same as the target. (For information on building a cross-compiler, see *Note Cross-Compiler::.) Here is an example: configure --target=sparc-sun-sunos4.1 If you run `configure' without specifying configuration arguments, `configure' tries to guess the type of host you are on, and uses that configuration type for both host and target. So you don't need to specify a configuration, for building a native compiler, unless `configure' cannot figure out what your configuration is. A configuration name may be canonical or it may be more or less abbreviated. A canonical configuration name has three parts, separated by dashes. It looks like this: `CPU-COMPANY-SYSTEM'. (The three parts may themselves contain dashes; `configure' can figure out which dashes serve which purpose.) For example, `m68k-sun-sunos4.1' specifies a Sun 3. You can also replace parts of the configuration by nicknames or aliases. For example, `sun3' stands for `m68k-sun', so `sun3-sunos4.1' is another way to specify a Sun 3. You can also use simply `sun3-sunos', since the version of SunOS is assumed by default to be version 4. `sun3-bsd' also works, since `configure' knows that the only BSD variant on a Sun 3 is SunOS. You can specify a version number after any of the system types, and some of the CPU types. In most cases, the version is irrelevant, and will be ignored. So you might as well specify the version if you know it. Here are the possible CPU types: a29k, alpha, arm, cN, clipper, elxsi, h8300, hppa1.0, hppa1.1, i370, i386, i486, i860, i960, m68000, m68k, m88k, mips, ns32k, pyramid, romp, rs6000, sh, sparc, sparclite, vax, we32k. Here are the recognized company names. As you can see, customary abbreviations are used rather than the longer official names. alliant, altos, apollo, att, bull, cbm, convergent, convex, crds, dec, dg, dolphin, elxsi, encore, harris, hitachi, hp, ibm, intergraph, isi, mips, motorola, ncr, next, ns, omron, plexus, sequent, sgi, sony, sun, tti, unicom. The company name is meaningful only to disambiguate when the rest of the information supplied is insufficient. You can omit it, writing just `CPU-SYSTEM', if it is not needed. For example, `vax-ultrix4.2' is equivalent to `vax-dec-ultrix4.2'. Here is a list of system types: aix, acis, aos, bsd, clix, ctix, dgux, dynix, genix, hpux, isc, linux, luna, lynxos, mach, minix, newsos, osf, osfrose, riscos, sco, solaris, sunos, sysv, ultrix, unos, vms. You can omit the system type; then `configure' guesses the operating system from the CPU and company. You can add a version number to the system type; this may or may not make a difference. For example, you can write `bsd4.3' or `bsd4.4' to distinguish versions of BSD. In practice, the version number is most needed for `sysv3' and `sysv4', which are often treated differently. If you specify an impossible combination such as `i860-dg-vms', then you may get an error message from `configure', or it may ignore part of the information and do the best it can with the rest. `configure' always prints the canonical name for the alternative that it used. Often a particular model of machine has a name. Many machine names are recognized as aliases for CPU/company combinations. Thus, the machine name `sun3', mentioned above, is an alias for `m68k-sun'. Sometimes we accept a company name as a machine name, when the name is popularly used for a particular machine. Here is a table of the known machine names: 3300, 3b1, 3bN, 7300, altos3068, altos, apollo68, att-7300, balance, convex-cN, crds, decstation-3100, decstation, delta, encore, fx2800, gmicro, hp7NN, hp8NN, hp9k2NN, hp9k3NN, hp9k7NN, hp9k8NN, iris4d, iris, isi68, m3230, magnum, merlin, miniframe, mmax, news-3600, news800, news, next, pbd, pc532, pmax, ps2, risc-news, rtpc, sun2, sun386i, sun386, sun3, sun4, symmetry, tower-32, tower. Remember that a machine name specifies both the cpu type and the company name. There are four additional options you can specify independently to describe variant hardware and software configurations. These are `--with-gnu-as', `--with-gnu-ld', `--with-stabs' and `--nfp'. `--with-gnu-as' If you will use GNU CC with the GNU assembler (GAS), you should declare this by using the `--with-gnu-as' option when you run `configure'. Using this option does not install GAS. It only modifies the output of GNU CC to work with GAS. Building and installing GAS is up to you. The systems where it makes a difference whether you use GAS are `hppa1.0-ANYTHING-ANYTHING', `hppa1.1-ANYTHING-ANYTHING', `i386-ANYTHING-sysv', `i860-ANYTHING-bsd', `m68k-bull-sysv', `m68k-hp-hpux', `m68k-sony-bsd', `m68k-altos-sysv', `m68000-hp-hpux', `m68000-att-sysv', and `mips-ANY'). On any other system, `--with-gnu-as' has no effect. On the systems listed above (except for the HP-PA), if you use GAS, you should also use the GNU linker (and specify `--with-gnu-ld'). `--with-gnu-ld' Specify the option `--with-gnu-ld' if you plan to use the GNU linker with GNU CC. This option does not cause the GNU linker to be installed; it just modifies the behavior of GNU CC to work with the GNU linker. Specifically, it inhibits the installation of `collect2', a program which otherwise serves as a front-end for the system's linker on most configurations. `--with-stabs' On MIPS based systems and on Alphas, you must specify whether you want GNU CC to create the normal ECOFF debugging format, or to use BSD-style stabs passed through the ECOFF symbol table. The normal ECOFF debug format cannot fully handle languages other than C. BSD stabs format can handle other languages, but it only works with the GNU debugger GDB. Normally, GNU CC uses the ECOFF debugging format by default; if you prefer BSD stabs, specify `--with-stabs' when you configure GNU CC. No matter which default you choose when you configure GNU CC, the user can use the `-gcoff' and `-gstabs+' options to specify explicitly the debug format for a particular compilation. `--nfp' On certain systems, you must specify whether the machine has a floating point unit. These systems include `m68k-sun-sunosN' and `m68k-isi-bsd'. On any other system, `--nfp' currently has no effect, though perhaps there are other systems where it could usefully make a difference. If you want to install your own homemade configuration files, you can use `local' as the company name to access them. If you use configuration `CPU-local', the configuration name without the cpu prefix is used to form the configuration file names. Thus, if you specify `m68k-local', configuration uses files `local.md', `local.h', `local.c', `xm-local.h', `t-local', and `x-local', all in the directory `config/m68k'. Here is a list of configurations that have special treatment or special things you must know: `alpha-*-osf1' Systems using processors that implement the DEC Alpha architecture and are running the OSF/1 operating system, for example the DEC Alpha AXP systems. (VMS on the Alpha is not currently supported by GNU CC.) GNU CC writes a `.verstamp' directive to the assembler output file unless it is built as a cross-compiler. It gets the version to use from the system header file `/usr/include/stamp.h'. If you install a new version of OSF/1, you should rebuild GCC to pick up the new version stamp. Note that since the Alpha is a 64-bit architecture, cross-compilers from 32-bit machines will not generate as efficient code as that generated when the compiler is running on a 64-bit machine because many optimizations that depend on being able to represent a word on the target in an integral value on the host cannot be performed. Building cross-compilers on the Alpha for 32-bit machines has only been tested in a few cases and may not work properly. `make compare' may fail on some versions of OSF/1 unless you add `-save-temps' to `BOOT_CFLAGS'. This forces a fixed name to be used for the assembler input file instead of a random name in `/tmp'. The name of the assembler input file is stored in the object file and will cause miscompared if it differs between the `stage1' and `stage2' compilations. GNU CC now supports both the native (ECOFF) debugging format used by DBX and GDB and an encapsulated STABS format for use only with GDB. See the discussion of the `--with-stabs' option of `configure' above for more information on these formats and how to select them. There is a bug in DEC's assembler that produces incorrect line numbers for ECOFF format when the `.align' directive is used. To work around this problem, GNU CC will not emit such alignment directives even if optimization is being performed if it is writing ECOFF format debugging information. Unfortunately, this has the very undesirable side-effect that code addresses when `-O' is specified are different depending on whether or not `-g' is also specified. To avoid this behavior, specify `-gstabs+' and use GDB instead of DBX. DEC is now aware of this problem with the assembler and hopes to provide a fix shortly. `a29k' AMD Am29k-family processors. These are normally used in embedded applications. There are no standard Unix configurations. This configuration corresponds to AMD's standard calling sequence and binary interface and is compatible with other 29k tools. You may need to make a variant of the file `a29k.h' for your particular configuration. `a29k-*-bsd' AMD Am29050 used in a system running a variant of BSD Unix. `elxsi-elxsi-bsd' The Elxsi's C compiler has known limitations that prevent it from compiling GNU C. Please contact `mrs@cygnus.com' for more details. `hppa*-*-*' Using GAS is highly recommended for all HP-PA configurations. See *Note PA Install:: for the special procedures needed to compile GNU CC for the HP-PA. `i386-*-sco' Compilation with RCC is recommended. Also, it may be a good idea to link with GNU malloc instead of the malloc that comes with the system. `i386-*-sco3.2.4' Use this configuration for SCO release 3.2 version 4. `i386-*-isc' It may be good idea to link with GNU malloc instead of the malloc that comes with the system. `i386-*-esix' It may be good idea to link with GNU malloc instead of the malloc that comes with the system. `i386-ibm-aix' You need to use GAS version 2.1 or later, and and LD from GNU binutils version 2.2 or later. `i386-sequent' Go to the Berkeley universe before compiling. In addition, you probably need to create a file named `string.h' containing just one line: `#include <strings.h>'. `i386-sun-sunos4' You may find that you need another version of GNU CC to begin bootstrapping with, since the current version when built with the system's own compiler seems to get an infinite loop compiling part of `libgcc2.c'. GNU CC version 2 compiled with GNU CC (any version) seems not to have this problem. `m68000-att' AT&T 3b1, a.k.a. 7300 PC. Special procedures are needed to compile GNU CC with this machine's standard C compiler, due to bugs in that compiler. *Note 3b1 Install::. You can bootstrap it more easily with previous versions of GNU CC if you have them. `m68000-hp-bsd' HP 9000 series 200 running BSD. Note that the C compiler that comes with this system cannot compile GNU CC; contact `law@cs.utah.edu' to get binaries of GNU CC for bootstrapping. `m68k-altos' Altos 3068. You must use the GNU assembler, linker and debugger. Also, you must fix a kernel bug. Details in the file `README.ALTOS'. `m68k-bull-sysv' Bull DPX/2 series 200 and 300 with BOS-2.00.45 up to BOS-2.01. GNU CC works either with native assembler or GNU assembler. You can use GNU assembler with native coff generation by providing `--gas' to the configure script or use GNU assembler with dbx-in-coff encapsulation by providing `--gas --stabs'. For any problem with native assembler or for availability of the DPX/2 port of GAS, contact `F.Pierresteguy@frcl.bull.fr'. `m68k-hp-hpux' HP 9000 series 300 or 400 running HP-UX. HP-UX version 8.0 has a bug in the assembler that prevents compilation of GNU CC. To fix it, get patch PHCO_0800 from HP. In addition, `--gas' does not currently work with this configuration. Changes in HP-UX have broken the library conversion tool and the linker. `m68k-sun' Sun 3. We do not provide a configuration file to use the Sun FPA by default, because programs that establish signal handlers for floating point traps inherently cannot work with the FPA. `m88k-*-svr3' Motorola m88k running the AT&T/Unisoft/Motorola V.3 reference port. These systems tend to use the Green Hills C, revision 1.8.5, as the standard C compiler. There are apparently bugs in this compiler that result in object files differences between stage 2 and stage 3. If this happens, make the stage 4 compiler and compare it to the stage 3 compiler. If the stage 3 and stage 4 object files are identical, this suggests you encountered a problem with the standard C compiler; the stage 3 and 4 compilers may be usable. It is best, however, to use an older version of GNU CC for bootstrapping if you have one. `m88k-*-dgux' Motorola m88k running DG/UX. To build native or cross compilers on DG/UX, you must first change to the 88open BCS software development environment. This is done by issuing this command: eval `sde-target m88kbcs` `m88k-tektronix-sysv3' Tektronix XD88 running UTekV 3.2e. Do not turn on optimization while building stage1 if you bootstrap with the buggy Green Hills compiler. Also, The bundled LAI System V NFS is buggy so if you build in an NFS mounted directory, start from a fresh reboot, or avoid NFS all together. Otherwise you may have trouble getting clean comparisons between stages. `mips-mips-bsd' MIPS machines running the MIPS operating system in BSD mode. It's possible that some old versions of the system lack the functions `memcpy', `memcmp', and `memset'. If your system lacks these, you must remove or undo the definition of `TARGET_MEM_FUNCTIONS' in `mips-bsd.h'. `mips-sgi-*' Silicon Graphics MIPS machines running IRIX. In order to compile GCC on an SGI the "c.hdr.lib" option must be installed from the CD-ROM supplied from Silicon Graphics. This is found on the 2nd CD in release 4.0.1. `mips-sony-sysv' Sony MIPS NEWS. This works in NEWSOS 5.0.1, but not in 5.0.2 (which uses ELF instead of COFF). Support for 5.0.2 will probably be provided soon by volunteers. In particular, the linker does not like the code generated by GCC when shared libraries are linked in. `ns32k-encore' Encore ns32000 system. Encore systems are supported only under BSD. `ns32k-*-genix' National Semiconductor ns32000 system. Genix has bugs in `alloca' and `malloc'; you must get the compiled versions of these from GNU Emacs. `ns32k-sequent' Go to the Berkeley universe before compiling. In addition, you probably need to create a file named `string.h' containing just one line: `#include <strings.h>'. `ns32k-utek' UTEK ns32000 system ("merlin"). The C compiler that comes with this system cannot compile GNU CC; contact `tektronix!reed!mason' to get binaries of GNU CC for bootstrapping. `romp-*-aos' `romp-*-mach' The only operating systems supported for the IBM RT PC are AOS and MACH. GNU CC does not support AIX running on the RT. We recommend you compile GNU CC with an earlier version of itself; if you compile GNU CC with `hc', the Metaware compiler, it will work, but you will get mismatches between the stage 2 and stage 3 compilers in various files. These errors are minor differences in some floating-point constants and can be safely ignored; the stage 3 compiler is correct. `rs6000-*-aix' *Read the file `README.RS6000' for information on how to get a fix for problems in the IBM assembler that interfere with GNU CC.* You must either obtain the new assembler or avoid using the `-g' switch. Note that `Makefile.in' uses `-g' by default when compiling `libgcc2.c'. The PowerPC and POWER2 architectures are now supported, but have not been extensively tested due to lack of appropriate systems. Only AIX is supported on the PowerPC. XLC version 1.3.0.0 will miscompile `jump.c'. XLC version 1.3.0.1 or later fixes this problem. We do not yet have a PTF number for this fix. `vax-dec-ultrix' Don't try compiling with Vax C (`vcc'). It produces incorrect code in some cases (for example, when `alloca' is used). Meanwhile, compiling `cp-parse.c' with pcc does not work because of an internal table size limitation in that compiler. To avoid this problem, compile just the GNU C compiler first, and use it to recompile building all the languages that you want to run. Here we spell out what files will be set up by `configure'. Normally you need not be concerned with these files. * A symbolic link named `config.h' is made to the top-level config file for the machine you will run the compiler on (*note Config::.). This file is responsible for defining information about the host machine. It includes `tm.h'. The top-level config file is located in the subdirectory `config'. Its name is always `xm-SOMETHING.h'; usually `xm-MACHINE.h', but there are some exceptions. If your system does not support symbolic links, you might want to set up `config.h' to contain a `#include' command which refers to the appropriate file. * A symbolic link named `tconfig.h' is made to the top-level config file for your target machine. This is used for compiling certain programs to run on that machine. * A symbolic link named `tm.h' is made to the machine-description macro file for your target machine. It should be in the subdirectory `config' and its name is often `MACHINE.h'. * A symbolic link named `md' will be made to the machine description pattern file. It should be in the `config' subdirectory and its name should be `MACHINE.md'; but MACHINE is often not the same as the name used in the `tm.h' file because the `md' files are more general. * A symbolic link named `aux-output.c' will be made to the output subroutine file for your machine. It should be in the `config' subdirectory and its name should be `MACHINE.c'. * The command file `configure' also constructs the file `Makefile' by adding some text to the template file `Makefile.in'. The additional text comes from files in the `config' directory, named `t-TARGET' and `x-HOST'. If these files do not exist, it means nothing needs to be added for a given target or host. 4. The standard directory for installing GNU CC is `/usr/local/lib'. If you want to install its files somewhere else, specify `--prefix=DIR' when you run `configure'. Here DIR is a directory name to use instead of `/usr/local' for all purposes with one exception: the directory `/usr/local/include' is searched for header files no matter where you install the compiler. 5. Specify `--local-prefix=DIR' if you want the compiler to search directory `DIR/include' for header files *instead* of `/usr/local/include'. (This is for systems that have different conventions for where to put site-specific things.) 6. Make sure the Bison parser generator is installed. (This is unnecessary if the Bison output files `c-parse.c' and `cexp.c' are more recent than `c-parse.y' and `cexp.y' and you do not plan to change the `.y' files.) Bison versions older than Sept 8, 1988 will produce incorrect output for `c-parse.c'. 7. Build the compiler. Just type `make LANGUAGES=c' in the compiler directory. `LANGUAGES=c' specifies that only the C compiler should be compiled. The makefile normally builds compilers for all the supported languages; currently, C, C++ and Objective C. However, C is the only language that is sure to work when you build with other non-GNU C compilers. In addition, building anything but C at this stage is a waste of time. In general, you can specify the languages to build by typing the argument `LANGUAGES="LIST"', where LIST is one or more words from the list `c', `c++', and `objective-c'. Ignore any warnings you may see about "statement not reached" in `insn-emit.c'; they are normal. Also, warnings about "unknown escape sequence" are normal in `genopinit.c' and perhaps some other files. Any other compilation errors may represent bugs in the port to your machine or operating system, and should be investigated and reported (*note Bugs::.). Some commercial compilers fail to compile GNU CC because they have bugs or limitations. For example, the Microsoft compiler is said to run out of macro space. Some Ultrix compilers run out of expression space; then you need to break up the statement where the problem happens. If you are building with a previous GNU C compiler, do not use `CC=gcc' on the make command or by editing the Makefile. Instead, use a full pathname to specify the compiler, such as `CC=/usr/local/bin/gcc'. This is because make might execute the `gcc' in the current directory before all of the compiler components have been built. 8. If you are building a cross-compiler, stop here. *Note Cross-Compiler::. 9. Move the first-stage object files and executables into a subdirectory with this command: make stage1 The files are moved into a subdirectory named `stage1'. Once installation is complete, you may wish to delete these files with `rm -r stage1'. 10. If you have chosen a configuration for GNU CC which requires other GNU tools (such as GAS or the GNU linker) instead of the standard system tools, install the required tools in the `stage1' subdirectory under the names `as', `ld' or whatever is appropriate. This will enable the stage 1 compiler to find the proper tools in the following stage. Alternatively, you can do subsequent compilation using a value of the `PATH' environment variable such that the necessary GNU tools come before the standard system tools. 11. Recompile the compiler with itself, with this command: make CC="stage1/xgcc -Bstage1/" CFLAGS="-g -O" This is called making the stage 2 compiler. The command shown above builds compilers for all the supported languages. If you don't want them all, you can specify the languages to build by typing the argument `LANGUAGES="LIST"'. LIST should contain one or more words from the list `c', `c++', `objective-c', and `proto'. Separate the words with spaces. `proto' stands for the programs `protoize' and `unprotoize'; they are not a separate language, but you use `LANGUAGES' to enable or disable their installation. If you are going to build the stage 3 compiler, then you might want to build only the C language in stage 2. Once you have built the stage 2 compiler, if you are short of disk space, you can delete the subdirectory `stage1'. On a 68000 or 68020 system lacking floating point hardware, unless you have selected a `tm.h' file that expects by default that there is no such hardware, do this instead: make CC="stage1/xgcc -Bstage1/" CFLAGS="-g -O -msoft-float" 12. If you wish to test the compiler by compiling it with itself one more time, install any other necessary GNU tools (such as GAS or the GNU linker) in the `stage2' subdirectory as you did in the `stage1' subdirectory, then do this: make stage2 make CC="stage2/xgcc -Bstage2/" CFLAGS="-g -O" This is called making the stage 3 compiler. Aside from the `-B' option, the compiler options should be the same as when you made the stage 2 compiler. But the `LANGUAGES' option need not be the same. The command shown above builds compilers for all the supported languages; if you don't want them all, you can specify the languages to build by typing the argument `LANGUAGES="LIST"', as described above. Then compare the latest object files with the stage 2 object files--they ought to be identical, unless they contain time stamps. You can compare the files, disregarding the time stamps if any, like this: make compare This will mention any object files that differ between stage 2 and stage 3. Any difference, no matter how innocuous, indicates that the stage 2 compiler has compiled GNU CC incorrectly, and is therefore a potentially serious bug which you should investigate and report (*note Bugs::.). If your system does not put time stamps in the object files, then this is a faster way to compare them (using the Bourne shell): for file in *.o; do cmp $file stage2/$file done If you have built the compiler with the `-mno-mips-tfile' option on MIPS machines, you will not be able to compare the files. The Alpha stores file names in the object files and `make compare' does not know how to ignore them, so normally you cannot compare on the Alpha. However, if you use the `-save-temps' option when compiling *both* stage 2 and stage 3, this causes the same file names to be used in both stages; then you can do the comparison. 13. Build the Objective C library (if you have built the Objective C compiler). Here is the command to do this: make objc-runtime CC="stage2/xgcc -Bstage2/" CFLAGS="-g -O" 14. Install the compiler driver, the compiler's passes and run-time support with `make install'. Use the same value for `CC', `CFLAGS' and `LANGUAGES' that you used when compiling the files that are being installed. One reason this is necessary is that some versions of Make have bugs and recompile files gratuitously when you do this step. If you use the same variable values, those files will be recompiled properly. For example, if you have built the stage 2 compiler, you can use the following command: make install CC="stage2/xgcc -Bstage2/" CFLAGS="-g -O" LANGUAGES="LIST" This copies the files `cc1', `cpp' and `libgcc.a' to files `cc1', `cpp' and `libgcc.a' in the directory `/usr/local/lib/gcc-lib/TARGET/VERSION', which is where the compiler driver program looks for them. Here TARGET is the target machine type specified when you ran `configure', and VERSION is the version number of GNU CC. This naming scheme permits various versions and/or cross-compilers to coexist. This also copies the driver program `xgcc' into `/usr/local/bin/gcc', so that it appears in typical execution search paths. On some systems, this command causes recompilation of some files. This is usually due to bugs in `make'. You should either ignore this problem, or use GNU Make. *Warning: there is a bug in `alloca' in the Sun library. To avoid this bug, be sure to install the executables of GNU CC that were compiled by GNU CC. (That is, the executables from stage 2 or 3, not stage 1.) They use `alloca' as a built-in function and never the one in the library.* (It is usually better to install GNU CC executables from stage 2 or 3, since they usually run faster than the ones compiled with some other compiler.) 15. Install the Objective C library (if you are installing the Objective C compiler). Here is the command to do this: make install-libobjc CC="stage2/xgcc -Bstage2/" CFLAGS="-g -O" 16. If you're going to use C++, it's likely that you need to also install the libg++ distribution. It should be available from the same place where you got the GNU C distribution. Just as GNU C does not distribute a C runtime library, it also does not include a C++ run-time library. All I/O functionality, special class libraries, etc., are available in the libg++ distribution. File: gcc.info, Node: Other Dir, Next: Cross-Compiler, Up: Installation Compilation in a Separate Directory =================================== If you wish to build the object files and executables in a directory other than the one containing the source files, here is what you must do differently: 1. Make sure you have a version of Make that supports the `VPATH' feature. (GNU Make supports it, as do Make versions on most BSD systems.) 2. If you have ever run `configure' in the source directory, you must undo the configuration. Do this by running: make distclean 3. Go to the directory in which you want to build the compiler before running `configure': mkdir gcc-sun3 cd gcc-sun3 On systems that do not support symbolic links, this directory must be on the same file system as the source code directory. 4. Specify where to find `configure' when you run it: ../gcc/configure ... This also tells `configure' where to find the compiler sources; `configure' takes the directory from the file name that was used to invoke it. But if you want to be sure, you can specify the source directory with the `--srcdir' option, like this: ../gcc/configure --srcdir=../gcc sun3 The directory you specify with `--srcdir' need not be the same as the one that `configure' is found in. Now, you can run `make' in that directory. You need not repeat the configuration steps shown above, when ordinary source files change. You must, however, run `configure' again when the configuration files change, if your system does not support symbolic links. File: gcc.info, Node: Cross-Compiler, Next: PA Install, Prev: Other Dir, Up: Installation Building and Installing a Cross-Compiler ======================================== GNU CC can function as a cross-compiler for many machines, but not all. * Cross-compilers for the Mips as target using the Mips assembler currently do not work, because the auxiliary programs `mips-tdump.c' and `mips-tfile.c' can't be compiled on anything but a Mips. It does work to cross compile for a Mips if you use the GNU assembler and linker. * Cross-compilers between machines with different floating point formats have not all been made to work. GNU CC now has a floating point emulator with which these can work, but each target machine description needs to be updated to take advantage of it. * Cross-compilation between machines of different word sizes has not really been addressed yet. Since GNU CC generates assembler code, you probably need a cross-assembler that GNU CC can run, in order to produce object files. If you want to link on other than the target machine, you need a cross-linker as well. You also need header files and libraries suitable for the target machine that you can install on the host machine. * Menu: * Steps of Cross:: Using a cross-compiler involves several steps that may be carried out on different machines. * Configure Cross:: Configuring a cross-compiler. * Tools and Libraries:: Where to put the linker and assembler, and the C library. * Cross Headers:: Finding and installing header files for a cross-compiler. * Cross Runtime:: Supplying arithmetic runtime routines (`libgcc1.a'). * Build Cross:: Actually compiling the cross-compiler. File: gcc.info, Node: Steps of Cross, Next: Configure Cross, Up: Cross-Compiler Steps of Cross-Compilation -------------------------- To compile and run a program using a cross-compiler involves several steps: * Run the cross-compiler on the host machine to produce assembler files for the target machine. This requires header files for the target machine. * Assemble the files produced by the cross-compiler. You can do this either with an assembler on the target machine, or with a cross-assembler on the host machine. * Link those files to make an executable. You can do this either with a linker on the target machine, or with a cross-linker on the host machine. Whichever machine you use, you need libraries and certain startup files (typically `crt....o') for the target machine. It is most convenient to do all of these steps on the same host machine, since then you can do it all with a single invocation of GNU CC. This requires a suitable cross-assembler and cross-linker. For some targets, the GNU assembler and linker are available. File: gcc.info, Node: Configure Cross, Next: Tools and Libraries, Prev: Steps of Cross, Up: Cross-Compiler Configuring a Cross-Compiler ---------------------------- To build GNU CC as a cross-compiler, you start out by running `configure'. You must specify two different configurations, the host and the target. Use the `--host=HOST' option for the host and `--target=TARGET' to specify the target type. For example, here is how to configure for a cross-compiler that runs on a hypothetical Intel 386 system and produces code for an HP 68030 system running BSD: configure --target=m68k-hp-bsd4.3 --host=i386-bozotheclone-bsd4.3 File: gcc.info, Node: Tools and Libraries, Next: Cross Headers, Prev: Configure Cross, Up: Cross-Compiler Tools and Libraries for a Cross-Compiler ---------------------------------------- If you have a cross-assembler and cross-linker available, you should install them now. Put them in the directory `/usr/local/TARGET/bin'. Here is a table of the tools you should put in this directory: `as' This should be the cross-assembler. `ld' This should be the cross-linker. `ar' This should be the cross-archiver: a program which can manipulate archive files (linker libraries) in the target machine's format. `ranlib' This should be a program to construct a symbol table in an archive file. The installation of GNU CC will find these programs in that directory, and copy or link them to the proper place to for the cross-compiler to find them when run later. The easiest way to provide these files is to build the Binutils package and GAS. Configure them with the same `--host' and `--target' options that you use for configuring GNU CC, then build and install them. They install their executables automatically into the proper directory. Alas, they do not support all the targets that GNU CC supports. If you want to install libraries to use with the cross-compiler, such as a standard C library, put them in the directory `/usr/local/TARGET/lib'; installation of GNU CC copies all all the files in that subdirectory into the proper place for GNU CC to find them and link with them. Here's an example of copying some libraries from a target machine: ftp TARGET-MACHINE lcd /usr/local/TARGET/lib cd /lib get libc.a cd /usr/lib get libg.a get libm.a quit The precise set of libraries you'll need, and their locations on the target machine, vary depending on its operating system. Many targets require "start files" such as `crt0.o' and `crtn.o' which are linked into each executable; these too should be placed in `/usr/local/TARGET/lib'. There may be several alternatives for `crt0.o', for use with profiling or other compilation options. Check your target's definition of `STARTFILE_SPEC' to find out what start files it uses. Here's an example of copying these files from a target machine: ftp TARGET-MACHINE lcd /usr/local/TARGET/lib prompt cd /lib mget *crt*.o cd /usr/lib mget *crt*.o quit File: gcc.info, Node: Cross Runtime, Next: Build Cross, Prev: Cross Headers, Up: Cross-Compiler `libgcc.a' and Cross-Compilers ------------------------------ Code compiled by GNU CC uses certain runtime support functions implicitly. Some of these functions can be compiled successfully with GNU CC itself, but a few cannot be. These problem functions are in the source file `libgcc1.c'; the library made from them is called `libgcc1.a'. When you build a native compiler, these functions are compiled with some other compiler-the one that you use for bootstrapping GNU CC. Presumably it knows how to open code these operations, or else knows how to call the run-time emulation facilities that the machine comes with. But this approach doesn't work for building a cross-compiler. The compiler that you use for building knows about the host system, not the target system. So, when you build a cross-compiler you have to supply a suitable library `libgcc1.a' that does the job it is expected to do. To compile `libgcc1.c' with the cross-compiler itself does not work. The functions in this file are supposed to implement arithmetic operations that GNU CC does not know how to open code, for your target machine. If these functions are compiled with GNU CC itself, they will compile into infinite recursion. On any given target, most of these functions are not needed. If GNU CC can open code an arithmetic operation, it will not call these functions to perform the operation. It is possible that on your target machine, none of these functions is needed. If so, you can supply an empty library as `libgcc1.a'. Many targets need library support only for multiplication and division. If you are linking with a library that contains functions for multiplication and division, you can tell GNU CC to call them directly by defining the macros `MULSI3_LIBCALL', and the like. These macros need to be defined in the target description macro file. For some targets, they are defined already. This may be sufficient to avoid the need for libgcc1.a; if so, you can supply an empty library. Some targets do not have floating point instructions; they need other functions in `libgcc1.a', which do floating arithmetic. Recent versions of GNU CC have a file which emulates floating point. With a certain amount of work, you should be able to construct a floating point emulator that can be used as `libgcc1.a'. Perhaps future versions will contain code to do this automatically and conveniently. That depends on whether someone wants to implement it. If your target system has another C compiler, you can configure GNU CC as a native compiler on that machine, build just `libgcc1.a' with `make libgcc1.a' on that machine, and use the resulting file with the cross-compiler. To do this, execute the following on the target machine: cd TARGET-BUILD-DIR configure --host=sparc --target=sun3 make libgcc1.a And then this on the host machine: ftp TARGET-MACHINE binary cd TARGET-BUILD-DIR get libgcc1.a quit Another way to provide the functions you need in `libgcc1.a' is to define the appropriate `perform_...' macros for those functions. If these definitions do not use the C arithmetic operators that they are meant to implement, you should be able to compile them with the cross-compiler you are building. (If these definitions already exist for your target file, then you are all set.) To build `libgcc1.a' using the perform macros, use `LIBGCC1=libgcc1.a OLDCC=./xgcc' when building the compiler. Otherwise, you should place your replacement library under the name `libgcc1.a' in the directory in which you will build the cross-compiler, before you run `make'. File: gcc.info, Node: Cross Headers, Next: Cross Runtime, Prev: Tools and Libraries, Up: Cross-Compiler Cross-Compilers and Header Files -------------------------------- If you are cross-compiling a standalone program or a program for an embedded system, then you may not need any header files except the few that are part of GNU CC (and those of your program). However, if you intend to link your program with a standard C library such as `libc.a', then you probably need to compile with the header files that go with the library you use. The GNU C compiler does not come with these files, because (1) they are system-specific, and (2) they belong in a C library, not in a compiler. If the GNU C library supports your target machine, then you can get the header files from there (assuming you actually use the GNU library when you link your program). If your target machine comes with a C compiler, it probably comes with suitable header files also. If you make these files accessible from the host machine, the cross-compiler can use them also. Otherwise, you're on your own in finding header files to use when cross-compiling. When you have found suitable header files, put them in `/usr/local/TARGET/include', before building the cross compiler. Then installation will run fixincludes properly and install the corrected versions of the header files where the compiler will use them. Provide the header files before you build the cross-compiler, because the build stage actually runs the cross-compiler to produce parts of `libgcc.a'. (These are the parts that *can* be compiled with GNU CC.) Some of them need suitable header files. Here's an example showing how to copy the header files from a target machine. On the target machine, do this: (cd /usr/include; tar cf - .) > tarfile Then, on the host machine, do this: ftp TARGET-MACHINE lcd /usr/local/TARGET/include get tarfile quit tar xf tarfile File: gcc.info, Node: Build Cross, Prev: Cross Runtime, Up: Cross-Compiler Actually Building the Cross-Compiler ------------------------------------ Now you can proceed just as for compiling a single-machine compiler through the step of building stage 1. If you have not provided some sort of `libgcc1.a', then compilation will give up at the point where it needs that file, printing a suitable error message. If you do provide `libgcc1.a', then building the compiler will automatically compile and link a test program called `cross-test'; if you get errors in the linking, it means that not all of the necessary routines in `libgcc1.a' are available. If you are making a cross-compiler for an embedded system, and there is no `stdio.h' header for it, then the compilation of `enquire' will probably fail. The job of `enquire' is to run on the target machine and figure out by experiment the nature of its floating point representation. `enquire' records its findings in the header file `float.h'. If you can't produce this file by running `enquire' on the target machine, then you will need to come up with a suitable `float.h' in some other way (or else, avoid using it in your programs). Do not try to build stage 2 for a cross-compiler. It doesn't work to rebuild GNU CC as a cross-compiler using the cross-compiler, because that would produce a program that runs on the target machine, not on the host. For example, if you compile a 386-to-68030 cross-compiler with itself, the result will not be right either for the 386 (because it was compiled into 68030 code) or for the 68030 (because it was configured for a 386 as the host). If you want to compile GNU CC into 68030 code, whether you compile it on a 68030 or with a cross-compiler on a 386, you must specify a 68030 as the host when you configure it. To install the cross-compiler, use `make install', as usual.