Otherware/Otherware_1_SB_Development.iso/amiga/programm/language/gcc222.lha/info/gcc.info-3

GNU Info File | 1992-07-19 | 49.3 KB | 1,169 lines

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 <strings.h>'.

    `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
          `[e-mail]' 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 <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.

    `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.