This is Info file gcc.info, produced by Makeinfo-1.47 from the input file gcc.texi. This file documents the use and the internals of the GNU compiler. Copyright (C) 1988, 1989, 1992 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 "Boycott" 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 "Boycott", 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: M88K Options, Next: RS/6000 Options, Prev: AMD29K Options, Up: Submodel Options M88K Options ------------ These `-m' options are defined for Motorola 88K architectures: `-m88000' Generate code that works well on both the m88100 and the m88110. `-m88100' Generate code tha Generate code that works best for the m88100, but that also runs on the m88110. `-m88110' Generate code that works best for the m88110, and may not run on the m88100. `-midentify-revision' Include an `ident' directive in the assembler output recording the source file name, compiler name and version, timestamp, and compilation flags used. `-mno-underscores' In assembler output, emit symbol names without adding an underscore character at the beginning of each name. The default is to use an underscore as prefix on each name. `-mocs-debug-info' `-mno-ocs-debug-info' Include (or omit) additional debugging information (about registers used in each stack frame) as specified in the 88open Object Compatibility Standard, "OCS". This extra information allows debugging of code that has had the frame pointer eliminated. The default for DG/UX, SVr4, and Delta 88 SVr3.2 is to include this information; other 88k configurations omit this information by default. `-mocs-frame-position' When emitting COFF debugging information for automatic variables and parameters stored on the stack, use the offset from the canonical frame address, which is the stack pointer (register 31) on entry to the function. The DG/UX, SVr4, Delta88 SVr3.2, and BCS configurations use `-mocs-frame-position'; other 88k configurations have the default `-mno-ocs-frame-position'. `-mno-ocs-frame-position' When emitting COFF debugging information for automatic variables and parameters stored on the stack, use the offset from the frame pointer register (register 30). When this option is in effect, the frame pointer is not eliminated when debugging information is selected by the -g switch. `-moptimize-arg-area' `-mno-optimize-arg-area' Control how to store function arguments in stack frames. `-moptimize-arg-area' saves space, but was ruled illegal by 88open. `-mno-optimize-arg-area' conforms to the 88open standards. By default GNU CC does not optimize the argument area. `-mshort-data-NUM' Generate smaller data references by making them relative to `r0', which allows loading a value using a single instruction (rather than the usual two). You control which data references are affected by specifying NUM with this option. For example, if you specify `-mshort-data-512', then the data references affected are those involving displacements of less than 512 bytes. `-mshort-data-NUM' is not effective for NUM greater than 64K. `-msvr4' `-msvr3' Turn on (`-msvr4') or off (`-msvr3') compiler extensions related to System V release 4 (SVr4). This controls the following: 1. Which variant of the assembler syntax to emit (which you can select independently using `-mversion-03.00'). 2. `-msvr4' makes the C preprocessor recognize `#pragma weak' that is used on System V release 4. 3. `-msvr4' makes GNU CC issue additional declaration directives used in SVr4. `-msvr3' is the default for all m88K configurations except the SVr4 configuration. `-mversion-03.00' In the DG/UX configuration, there are two flavors of SVr4. This option modifies `-msvr4' to select whether the hybrid-COFF or real-ELF flavor is used. All other configurations ignore this option. `-mno-check-zero-division' `-mcheck-zero-division' Early models of the 88K architecture had problems with division by zero; in particular, many of them didn't trap. Use these options to avoid including (or to include explicitly) additional code to detect division by zero and signal an exception. All GNU CC configurations for the 88K use `-mcheck-zero-division' by default. `-muse-div-instruction' Do not emit code to check both the divisor and dividend when doing signed integer division to see if either is negative, and adjust the signs so the divide is done using non-negative numbers. Instead, rely on the operating system to calculate the correct value when the `div' instruction traps. This results in different behavior when the most negative number is divided by -1, but is useful when most or all signed integer divisions are done with positive numbers. `-mtrap-large-shift' `-mhandle-large-shift' Include code to detect bit-shifts of more than 31 bits; respectively, trap such shifts or emit code to handle them properly. By default GNU CC makes no special provision for large bit shifts. `-mwarn-passed-structs' Warn when a function passes a struct as an argument or result. Structure-passing conventions have changed during the evolution of the C language, and are often the source of portability problems. By default, GNU CC issues no such warning. File: gcc.info, Node: RS/6000 Options, Next: RT Options, Prev: M88K Options, Up: Submodel Options IBM RS/6000 Options ------------------- Only one pair of `-m' options is defined for the IBM RS/6000: `-mfp-in-toc' `-mno-fp-in-toc' Control whether or not floating-point constants go in the Table of Contents (TOC), a table of all global variable and function addresses. By default GNU CC puts floating-point constants there; if the TOC overflows, `-mno-fp-in-toc' will reduce the size of the TOC, which may avoid the overflow. File: gcc.info, Node: RT Options, Next: MIPS Options, Prev: RS/6000 Options, Up: Submodel Options IBM RT Options -------------- These `-m' options are defined for the IBM RT PC: `-min-line-mul' Use an in-line code sequence for integer multiplies. This is the default. `-mcall-lib-mul' Call `lmul$$' for integer multiples. `-mfull-fp-blocks' Generate full-size floating point data blocks, including the minimum amount of scratch space recommended by IBM. This is the default. `-mminimum-fp-blocks' Do not include extra scratch space in floating point data blocks. This results in smaller code, but slower execution, since scratch space must be allocated dynamically. `-mfp-arg-in-fpregs' Use a calling sequence incompatible with the IBM calling convention in which floating point arguments are passed in floating point registers. Note that `varargs.h' and `stdargs.h' will not work with floating point operands if this option is specified. `-mfp-arg-in-gregs' Use the normal calling convention for floating point arguments. This is the default. `-mhc-struct-return' Return structures of more than one word in memory, rather than in a register. This provides compatibility with the MetaWare HighC (hc) compiler. Use `-fpcc-struct-return' for compatibility with the Portable C Compiler (pcc). `-mnohc-struct-return' Return some structures of more than one word in registers, when convenient. This is the default. For compatibility with the IBM-supplied compilers, use either `-fpcc-struct-return' or `-mhc-struct-return'. File: gcc.info, Node: MIPS Options, Next: i386 Options, Prev: RT Options, Up: Submodel Options MIPS Options ------------ These `-m' options are defined for the MIPS family of computers: `-mcpu=CPU TYPE' Assume the defaults for the machine type CPU TYPE when scheduling instructions. The default CPU TYPE is `default', which picks the longest cycles times for any of the machines, in order that the code run at reasonable rates on all MIPS cpu's. Other choices for CPU TYPE are `r2000', `r3000', `r4000', and `r6000'. While picking a specific CPU TYPE will schedule things appropriately for that particular chip, the compiler will not generate any code that does not meet level 1 of the MIPS ISA (instruction set architecture) without the `-mips2' or `-mips3' switches being used. `-mips2' Issue instructions from level 2 of the MIPS ISA (branch likely, square root instructions). The `-mcpu=r4000' or `-mcpu=r6000' switch must be used in conjunction with `-mips2'. `-mips3' Issue instructions from level 3 of the MIPS ISA (64 bit instructions). You must use the `-mcpu=r4000' switch along with `-mips3'. `-mint64' `-mlong64' `-mlonglong128' These options don't work at present. `-mmips-as' Generate code for the MIPS assembler, and invoke `mips-tfile' to add normal debug information. This is the default for all platforms except for the OSF/1 reference platform, using the OSF/rose object format. If the either of the `-gstabs' or `-gstabs+' switches are used, the `mips-tfile' program will encapsulate the stabs within MIPS ECOFF. `-mgas' Generate code for the GNU assembler. This is the default on the OSF/1 reference platform, using the OSF/rose object format. `-mrnames' `-mno-rnames' The `-mrnames' switch says to output code using the MIPS software names for the registers, instead of the hardware names (ie, A0 instead of $4). The GNU assembler does not support the `-mrnames' switch, and the MIPS assembler will be instructed to run the MIPS C preprocessor over the source file. The `-mno-rnames' switch is default. `-mgpopt' `-mno-gpopt' The `-mgpopt' switch says to write all of the data declarations before the instructions in the text section, this allows the MIPS assembler to generate one word memory references instead of using two words for short global or static data items. This is on by default if optimization is selected. `-mstats' `-mno-stats' For each non-inline function processed, the `-mstats' switch causes the compiler to emit one line to the standard error file to print statistics about the program (number of registers saved, stack size, etc.). `-mmemcpy' `-mno-memcpy' The `-mmemcpy' switch makes all block moves call the appropriate string function (`memcpy' or `bcopy') instead of possibly generating inline code. `-mmips-tfile' `-mno-mips-tfile' The `-mno-mips-tfile' switch causes the compiler not postprocess the object file with the `mips-tfile' program, after the MIPS assembler has generated it to add debug support. If `mips-tfile' is not run, then no local variables will be available to the debugger. In addition, `stage2' and `stage3' objects will have the temporary file names passed to the assembler embedded in the object file, which means the objects will not compare the same. The `-mno-mips-tfile' switch should only be used when there are bugs in the `mips-tfile' program that prevents compilation. `-msoft-float' Generate output containing library calls for floating point. *Warning:* the requisite libraries are not part of GNU CC. Normally the facilities of the machine's usual C compiler are used, but this can't be done directly in cross-compilation. You must make your own arrangements to provide suitable library functions for cross-compilation. `-mhard-float' Generate output containing floating point instructions. This is the default if you use the unmodified sources. `-mfp64' Assume that the FR bit in the status word is on, and that there are 32 64-bit floating point registers, instead of 32 32-bit floating point registers. You must also specify the `-mcpu=r4000' and `-mips3' switches. `-mfp32' Assume that there are 32 32-bit floating point registers. This is the default. `-mabicalls' `-mno-abicalls' Emit the `.abicalls', `.cpload', and `.cprestore' pseudo operations that some System V.4 ports use for position independent code. `-mhalf-pic' `-mno-half-pic' Put pointers to extern references into the data section and load them up, rather than put the references in the text section. These options do not work at present. `-G NUM' Put global and static items less than or equal to NUM bytes into the small data or bss sections instead of the normal data or bss section. This allows the assembler to emit one word memory reference instructions based on the global pointer (GP or $28), instead of the normal two words used. By default, NUM is 8 when the MIPS assembler is used, and 0 when the GNU assembler is used. The `-G NUM' switch is also passed to the assembler and linker. All modules should be compiled with the same `-G NUM' value. `-nocpp' Tell the MIPS assembler to not run it's preprocessor over user assembler files (with a `.s' suffix) when assembling them. These options are defined by the macro `TARGET_SWITCHES' in the machine description. The default for the options is also defined by that macro, which enables you to change the defaults. File: gcc.info, Node: i386 Options, Prev: MIPS Options, Up: Submodel Options Intel 386 Options ----------------- These `-m' options are defined for the i386 family of computers: `-m486' `-mno486' Control whether or not code is optimized for a 486 instead of an 386. Code generated for an 486 will run on a 386 and vice versa. `-msoft-float' Generate output containing library calls for floating point. *Warning:* the requisite libraries are not part of GNU CC. Normally the facilities of the machine's usual C compiler are used, but this can't be done directly in cross-compilation. You must make your own arrangements to provide suitable library functions for cross-compilation. On machines where a function returnings float point results in the 80387 register stack, some floating point opcodes may be emitted even if `-msoft-float' is used. File: gcc.info, Node: Code Gen Options, Next: Environment Variables, Prev: Submodel Options, Up: Invoking GCC Options for Code Generation Conventions ======================================= These machine-independent options control the interface conventions used in code generation. Most of them have both positive and negative forms; the negative form of `-ffoo' would be `-fno-foo'. In the table below, only one of the forms is listed--the one which is not the default. You can figure out the other form by either removing `no-' or adding it. `-fpcc-struct-return' Use the same convention for returning `struct' and `union' values that is used by the usual C compiler on your system. This convention is less efficient for small structures, and on many machines it fails to be reentrant; but it has the advantage of allowing intercallability between GNU CC-compiled code and PCC-compiled code. `-fshort-enums' Allocate to an `enum' type only as many bytes as it needs for the declared range of possible values. Specifically, the `enum' type will be equivalent to the smallest integer type which has enough room. `-fshort-double' Use the same size for `double' as for `float'. `-fshared-data' Requests that the data and non-`const' variables of this compilation be shared data rather than private data. The distinction makes sense only on certain operating systems, where shared data is shared between processes running the same program, while private data exists in one copy per process. `-fno-common' Allocate even uninitialized global variables in the bss section of the object file, rather than generating them as common blocks. This has the effect that if the same variable is declared (without `extern') in two different compilations, you will get an error when you link them. The only reason this might be useful is if you wish to verify that the program will work on other systems which always work this way. `-fno-ident' Ignore the `#ident' directive. `-fno-gnu-linker' Don't output global initializations such as C++ constructors and destructors in the form used by the GNU linker (on systems where the GNU linker is the standard method of handling them). Use this option when you want to use a "collect" program and a non-GNU linker. `-finhibit-size-directive' Don't output a `.size' assembler directive, or anything else that would cause trouble if the function is split in the middle, and the two halves are placed at locations far apart in memory. This option is used when compiling `crtstuff.c'; you should not need to use it for anything else. `-fverbose-asm' Put extra commentary information in the generated assembly code to make it more readable. This option is generally only of use to those who actually need to read the generated assembly code (perhaps while debugging the compiler itself). `-fvolatile' Consider all memory references through pointers to be volatile. `-fpic' If supported for the target machines, generate position-independent code, suitable for use in a shared library. All addresses will be accessed through a global offset table (GOT). If the GOT size for the linked executable exceeds a machine-specific maximum size, you will get an error message from the linker indicating that `-fpic' does not work; recompile with `-fPIC' instead. (These maximums are 16k on the m88k, 8k on the Sparc, and 32k on the m68k and RS/6000. The 386 has no such limit.) Position-independent code requires special support, and therefore works only on certain machines. Code generated for the IBM RS/6000 is always position-independent. The GNU assembler does not fully support PIC. Currently, you must use some other assembler in order for PIC to work. We would welcome volunteers to upgrade GAS to handle this; the first part of the job is to figure out what the assembler must do differently. `-fPIC' If supported for the target machine, emit position-independent code, suitable for dynamic linking and avoiding any limit on the size of the global offset table. This option makes a difference on the m68k, m88k and the Sparc. Position-independent code requires special support, and therefore works only on certain machines. `-ffixed-REG' Treat the register named REG as a fixed register; generated code should never refer to it (except perhaps as a stack pointer, frame pointer or in some other fixed role). REG must be the name of a register. The register names accepted are machine-specific and are defined in the `REGISTER_NAMES' macro in the machine description macro file. This flag does not have a negative form, because it specifies a three-way choice. `-fcall-used-REG' Treat the register named REG as an allocatable register that is clobbered by function calls. It may be allocated for temporaries or variables that do not live across a call. Functions compiled this way will not save and restore the register REG. Use of this flag for a register that has a fixed pervasive role in the machine's execution model, such as the stack pointer or frame pointer, will produce disastrous results. This flag does not have a negative form, because it specifies a three-way choice. `-fcall-saved-REG' Treat the register named REG as an allocatable register saved by functions. It may be allocated even for temporaries or variables that live across a call. Functions compiled this way will save and restore the register REG if they use it. Use of this flag for a register that has a fixed pervasive role in the machine's execution model, such as the stack pointer or frame pointer, will produce disastrous results. A different sort of disaster will result from the use of this flag for a register in which function values may be returned. This flag does not have a negative form, because it specifies a three-way choice. File: gcc.info, Node: Environment Variables, Prev: Code Gen Options, Up: Invoking GCC Environment Variables Affecting GNU CC ====================================== This section describes several environment variables that affect how GNU CC operates. They work by specifying directories or prefixes to use when searching for various kinds of files. Note that you can also specify places to search using options such as `-B', `-I' and `-L' (*note Directory Options::.). These take precedence over places specified using environment variables, which in turn take precedence over those specified by the configuration of GNU CC. *Note Driver::. `TMPDIR' If `TMPDIR' is set, it specifies the directory to use for temporary files. GNU CC uses temporary files to hold the output of one stage of compilation which is to be used as input to the next stage: for example, the output of the preprocessor, which is the input to the compiler proper. `GCC_EXEC_PREFIX' If `GCC_EXEC_PREFIX' is set, it specifies a prefix to use in the names of the subprograms executed by the compiler. No slash is added when this prefix is combined with the name of a subprogram, but you can specify a prefix that ends with a slash if you wish. If GNU CC cannot find the subprogram using the specified prefix, it tries looking in the usual places for the subprogram. Other prefixes specified with `-B' take precedence over this prefix. This prefix is also used for finding files such as `crt0.o' that are used for linking. In addition, the prefix is used in an unusual way in finding the directories to search for header files. For each of the standard directories whose name normally begins with `/usr/local/lib/gcc-lib' (more precisely, with the value of `GCC_INCLUDE_DIR'), GNU CC tries replacing that beginning with the specified prefix to produce an alternate directory name. Thus, with `-Bfoo/', GNU CC will search `foo/bar' where it would normally search `/usr/local/lib/bar'. These alternate directories are searched first; the standard directories come next. `COMPILER_PATH' The value of `COMPILER_PATH' is a colon-separated list of directories, much like `PATH'. GNU CC tries the directories thus specified when searching for subprograms, if it can't find the subprograms using `GCC_EXEC_PREFIX'. `LIBRARY_PATH' The value of `LIBRARY_PATH' is a colon-separated list of directories, much like `PATH'. GNU CC tries the directories thus specified when searching for special linker files, if it can't find them using `GCC_EXEC_PREFIX'. Linking using GNU CC also uses these directories when searching for ordinary libraries for the `-l' option (but directories specified with `-L' come first). `C_INCLUDE_PATH' `CPLUS_INCLUDE_PATH' `OBJC_INCLUDE_PATH' These environment variables pertain to particular languages. Each variable's value is a colon-separated list of directories, much like `PATH'. When GNU CC searches for header files, it tries the directories listed in the variable for the language you are using, after the directories specified with `-I' but before the standard header file directories. `DEPENDENCIES_OUTPUT' If this variable is set, its value specifies how to output dependencies for Make based on the header files processed by the compiler. This output looks much like the output from the `-M' option (*note Preprocessor Options::.), but it goes to a separate file, and is in addition to the usual results of compilation. The value of `DEPENDENCIES_OUTPUT' can be just a file name, in which case the Make rules are written to that file, guessing the target name from the source file name. Or the value can have the form `FILE TARGET', in which case the rules are written to file FILE using TARGET as the target name. File: gcc.info, Node: Installation, Next: 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. 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. 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. Use 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::.) The command looks like this: configure --target=sparc-sun-sunos4.1 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, arm, cN, hppa1.0, hppa1.1, i386, i860, i960, m68000, m68k, m88k, mips, ns32k, romp, rs6000, sparc, 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, convergent, convex, crds, dec, dg, encore, harris, hp, ibm, mips, motorola, ncr, next, ns, omron, 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: bsd, sysv, mach, minix, genix, ultrix, vms, sco, isc, aix, sunos, hpux, unos, luna, dgux, newsos, osfrose, osf, dynix, aos, ctix. 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 three additional options you can specify independently to describe variant hardware and software configurations. These are `--with-gnu-as', `--with-gnu-ld', and `--nfp'. `--with-gnu-as' On certain systems, you must specify whether you want GNU CC to work with the usual compilation tools or with the GNU compilation tools (including GAS). Use the `--with-gnu-as' argument when you run `configure', if you want to use the GNU tools. (Specify `--with-gnu-ld' as well, since on these systems GAS works only with the GNU linker.) The systems were this makes a difference are `i386-ANYTHING-sysv', `i860-ANYTHING-bsd', `m68k-hp-hpux', `m68k-sony-bsd', `m68k-altos-sysv', `m68000-hp-hpux', and `m68000-att-sysv'. On any other system, `--with-gnu-as' has no effect. `--with-gnu-ld' Specify the option `--with-gnu-ld' if you plan to use the GNU linker. This inhibits the installation of `collect2', a program which otherwise serves as a front-end for the system's linker on most configurations. `--nfp' On certain systems, you must specify whether the machine has a floating point unit. These systems are `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 entire configuration name is used to form the configuration file names. Thus, if you specify `m68k-local', then the files used are `m68k-local.md', `m68k-local.h', `m68k-local.c', `xm-m68k-local.h', `t-m68k-local', and `x-m68k-local'. Here is a list of configurations that have special treatment or special things you must know: `i386-*-sco' Compilation with RCC is recommended, but it produces lots of spurious warnings. They do not necessarily indicate that anything is wrong. `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 '. `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, with COFF-encapsulation. Also, you must fix a kernel bug. Details in the file `README.ALTOS'. `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/Motorla 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 a problem with the standard C compiler. It is best, however, to use an older version of GNU CC for bootstrapping. `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` `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-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. `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 '. `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. `rs6000-*-aix' Read the file `README.RS6000' for information on how to get a fix for a problem in the IBM assembler that prevents use of GNU CC. `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. `we32k-att-sysv' Don't use `-g' when compiling GNU CC. The system's linker seems to be unable to handle such a large program with debugging information. 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 `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 `h-HOST'. If these files do not exist, it means nothing needs to be added for a given target or host. 4. 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'. 5. 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. 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. 6. If you are using COFF-encapsulation, you must convert `libgcc.a' to a GNU-format library at this point. See the file `README.ENCAP' in the directory containing the GNU binary file utilities, for directions. 7. If you are building a cross-compiler, stop here. *Note Cross-Compiler::. 8. 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'. 9. Recompile the compiler with itself, with this command: make CC="stage1/gcc -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/gcc -Bstage1/" CFLAGS="-g -O -msoft-float" 10. If you wish to test the compiler by compiling it with itself one more time, do this: make stage2 make CC="stage2/gcc -Bstage2/" CFLAGS="-g -O" This is called making the stage 3 compiler. Aside from the `-B' option, the options should be the same as when you made 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"', 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. 11. Install the compiler driver, the compiler's passes and run-time support. You can use the following command: make CC="stage2/gcc -Bstage2/" CFLAGS="-g -O" install LANGUAGES="LIST" (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. This copies the files `cc1', `cpp' and `libgcc.a' to files `cc1', `cpp' and `libgcc.a' in 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. It also copies the driver program `gcc' into the directory `/usr/local/bin', so that it appears in typical execution search paths. On some systems, this command will cause 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.) 12. Correct errors in the header files on your machine. Various system header files often contain constructs which are incompatible with ANSI C, and they will not work when you compile programs with GNU CC. This behavior consists of substituting for macro argument names when they appear inside of character constants. The most common offender is `ioctl.h'. You can overcome this problem when you compile by specifying the `-traditional' option. Alternatively, on Sun systems and 4.3BSD at least, you can correct the include files by running the shell script `fixincludes'. This installs modified, corrected copies of the files `ioctl.h', `ttychars.h' and many others, in a special directory where only GNU CC will normally look for them. This script will work on various systems because it chooses the files by searching all the system headers for the problem cases that we know about. Use the following command to do this: make install-fixincludes If you selected a different directory for GNU CC installation when you installed it, by specifying the Make variable `prefix' or `libdir', specify it the same way in this command. Note that some systems are starting to come with ANSI C system header files. On these systems, don't run `fixincludes'; it may not work, and is certainly not necessary. If you cannot install the compiler's passes and run-time support in `/usr/local/lib', you can alternatively use the `-B' option to specify a prefix by which they may be found. The compiler concatenates the prefix with the names `cpp', `cc1' and `libgcc.a'. Thus, you can put the files in a directory `/usr/foo/gcc' and specify `-B/usr/foo/gcc/' when you run GNU CC. Also, you can specify an alternative default directory for these files by setting the Make variable `libdir' when you make GNU CC. 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.