Installing GNU Pascal
*********************

   The preferred way to distribute GNU software is distribution of the
source code. However, it can be a non-trivial exercise to build GNU
Pascal on some non-UNIX systems, so we also provide ready-to-run
binaries for a number of platforms. *Note binary distributions:: how to
install a binary distribution.

   GPC is based on GNU CC; you will need the GCC sources to build it.
It must be the same version as the one GPC is implemented with.
Although you need GCC to build the GNU Pascal compiler, you don't need
GCC to compile Pascal programs once GNU Pascal is installed. Because
GNU Pascal shares its backend with GNU CC, it should run on any system
supported by GNU CC. A full list of platforms supported by GNU CC can
be found in chapter 4 of the GCC manual, "Using and Porting GNU CC"

   Here is the generic procedure for installing GNU Pascal on a Unix
system.  *Note compilation notes:: for extra information needed to
install GPC on certain platforms.

  1. Unpack the source distributions.

     From a directory of your choice, unpack the GNU CC and GNU Pascal
     source distributions. This will create seperate subdirectories for
     GCC and GPC.

     `cd' to the GPC directory and move the contents (a directory "p" ,
     `COPYING.gpc' and `README.gpc') to the GCC directory.

     Next, go to the GCC source directory and apply the GCC patch
     required by GNU Pascal:

          % patch -s -p1 < p/patches/gcc-2.7.2.1.patch

     Note 1: In the example above, GCC version 2.7.2.1 is assumed. If
     your version of GCC is other than 2.7.2.1, you have to apply the
     appropriate patch.

     Note 2: All changes to GCC are surrounded by `#ifdef GPC ..
     #endif', so they should not interfere when you build a C compiler
     from this source tree.

     It is possible, though not required, to build the compiler in a
     directory other than the one containing the sources. In that case,
     you need a `make' that understands the VPATH variable. GNU make
     does, although at least GNU make version 3.71 has a bug in the way
     it treats VPATH.  GNU make version 3.75 is known to work.

     If you have built GNU Pascal previously in the same directory for a
     different target machine, do `make distclean' to delete all files
     that might be invalid.  One of the files this deletes is
     `Makefile'; if `make distclean' complains that `Makefile' does not
     exist, it probably means that the directory is already suitably
     clean.

  2. Configuring and building GNU CC GNU Pascal is automatically
     configured with GNU CC.  Configuration of GNU CC is treated in
     depth in Chapter 4 of "Using and Porting GNU CC"

     Chdir to the GCC object directory. Usually,

          % ../gcc-2.7.2.1/configure --prefix=/usr

     will do the job. This creates all the necessary config files,
     links and Makefile in the GCC object directory.

  3. The standard directory for installing GNU CC and GNU Pascal is
     `/usr/local/lib'. If you want to install its files somewhere else,
     specify `--prefix=DIR' when you run `configure'.  Here DIR is a
     directory name to use instead of `/usr/local' for all purposes
     with one exception: the directory `/usr/local/include' is searched
     for header files no matter where you install the compiler.  To
     override this name, use the `--local-prefix' option below.

  4. Specify `--local-prefix=DIR' if you want the compiler to search
     directory `DIR/include' for locally installed header files
     *instead* of `/usr/local/include'.

     You should specify `--local-prefix' *only* if your site has a
     different convention (not `/usr/local') for where to put
     site-specific files.

     *Do not* specify `/usr' as the `--local-prefix'!  The directory
     you use for `--local-prefix' *must not* contain any of the
     system's standard header files.  If it did contain them, certain
     programs would be miscompiled (including GNU Emacs, on certain
     targets), because this would override and nullify the header file
     corrections made by the `fixincludes' script.

  5. 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'.

  6. If you have chosen a configuration for GNU Pascal which requires
     other GNU tools (such as GAS or the GNU linker) instead of the
     standard system tools, install the required tools in the build
     directory under the names `as', `ld' or whatever is appropriate.
     This will enable the compiler to find the proper tools for
     compilation of the program `enquire'.

     Alternatively, you can do subsequent compilation using a value of
     the `PATH' environment variable such that the necessary GNU tools
     come before the standard system tools.

  7. Once you are satisfied with the configuration as determined by
     `configure', you can build the Pascal compiler:

          % make LANGUAGES=pascal

     (Just `make' would also build the C++ and Objective C compilers).
     Notice that this procedure will build the C compiler too, because
     that is used to compile the GPC runtime library.

     Optionally, you may supply CFLAGS, LDFLAGS or RTSFLAGS. CFLAGS is
     used for compiler and RTS, RTSFLAGS are for RTS only, i.e.: `make
     CFLAGS="-O2" RTSFLAGS=-Wall'

  8. When everything compiles, you can verify what the `make -n
     pascal.install' command does, and if you are satisfied run it
     without the `-n' option to install the compiler `gpc1', front end
     `gpc', run time system `libgpc.a' to the same place where gcc was
     installed. This installation process does NOT overwrite existing
     copies of `libgcc.a' or `specs', should they exist.

     You can also install GPC as part of the complete GNU compiler
     suite using "make install" as described in the GCC installation
     docs.


Configuration dependent compilation notes
=========================================

Alpha OSF/1
-----------

   For alpha OSF/1 v3.2 (GCC 2.6.3): If your linker starts to output
error messages like:

     Warning: Linking some objects which contain exception information sections
         and some which do not. This may cause fatal runtime exception handling
         problems (last obj encountered without exceptions was <OBJ/LIB>)

   I do not know why these started to appear, but you can get rid of
these if you do as follows in the GPC object directory.

   You need to trigger the Makefile dependencies, e.g. by doing the
touch command below. What happens is that it re-generates the version.c
and rts/version.c files, which need to be recompiled with `ALPHA_BUG'
defined.

   Example:
     % touch Makefile
     % make MY_CFLAGS=-DALPHA_BUG other-make-flags-you-want-to-use

MS-DOS with DJGPP
-----------------

   You cannot build GNU CC (or GNU Pascal) by itself on MS-DOS; it will
not compile under any MS-DOS compiler except itself. The official
MS-DOS port of GCC is called djgpp, and it is available from
`simtel.coast.net' and it has mirrors all over the world. The
`configure' script is replaced by an MS-DOS batch file called
`configure.bat' wich does essentially the same. Detailed instructions
are in the file `config/msdos/README.dj' of the GNU Pascal source
distribution.

MS-DOS or OS/2 with EMX
-----------------------

   EMX is a free 32-bit DOS extender which adds some properties of UNIX
to the DOS and OS/2 operating systems written by Eberhard Mattes.  You
can find it, for example, via anonymous `ftp' on the server
`ftp.uni-stuttgart.de' in the directory `pub/systems/os2/emx*'.

   Due to the limitation of the command ine to 128 characters we don't
know a way to compile GPC for EMX under DOS; you need OS/2 instead.  If
you succeed to compile GPC for EMX on a DOS system, please let us know.
(However you can compile GPC for DJGPP on a DOS system.)

  1. Unzip the source for GCC from the root directory, and rename the
     resulting directory `gcc-2.7' to `gpc'.
            cd \
            pkunzip -d c:\gccsrc1
            pkunzip -d c:\gccsrc2
            pkunzip -d c:\gccsrc3
            ren \emx\gnu\gcc-2.7 gpc

  2. Unzip the source for GPC from the `emx\gnu' directory, so it will
     go into the gpc subdirectory.  Unlike other EMX sources, the GPC
     source must *not* be extracted from the root directory.
            cd \emx\gnu
            pkunzip -d c:\gpc20bs

  3. Compile GPC using the `compile.cmd' script.
            cd \emx\gnu\gpc\p
            compile

  4. To install, move the GPC files in place.
            cd \emx\gnu\gpc
            copy gpc*.exe \emx\bin
            copy libgpc.a \emx\lib


Windows NT and Windows 95 with cygwin32
---------------------------------------

   cygwin32 is a project to make it easy to port Unix applications to
machines which run an OS which supports the Win32 API - i.e. Microsoft
Windows 95 and Windows NT. Currently, cygwin32 is in beta stage; it is
available from `ftp://ftp.cygnus.com/pub/gnu-win32/' Don't use gcc
sources from the cygwin32 distribution. These are not just modified from
FSF gcc-2.7.2 to support the Windows 95/NT target, they are the "current
development release", and too different from FSF gcc to be compatible
with GNU Pascal, which is based on FSF sources.

   Instead, apply `config/cygwin32/gcc-2.7.2.cygwin32-beta16.diff' to
FSF gcc-2.7.2 to add cygwin32 platform support to gcc.  The GNU pascal
sources already have the cygwin32 support, so no further patching of
gpc is needed

   Currently, cygwin32 is not self-hosting: the preferred way to build
the cygwin32-gpc binary is to use a unix system with a cygwin32
targeting crosscompiler. *Note Crossbuilding::

   GNU Pascal does not yet fully support the stack calling convention
of the Win32 API, thus making it impossible to access system DLL's.

Building and Installing a crosscompiler
=======================================

   GNU Pascal can function as a cross-compiler for many machines, but
not all.  Also, only a few combinations have been tested. If you need
information about GNU tools in a cross-configuration,
`ftp://ftp.cygnus.com/pub/embedded/crossgcc/' is the place to be.

   * Cross-compilers for the Mips as target using the Mips assembler
     currently do not work, because the auxiliary programs
     `mips-tdump.c' and `mips-tfile.c' can't be compiled on anything
     but a Mips.  It does work to cross compile for a Mips if you use
     the GNU assembler and linker.

   * Cross-compilers between machines with different floating point
     formats have not all been made to work.  GNU C now has a floating
     point emulator with which these can work, but each target machine
     description needs to be updated to take advantage of it.

   * Cross-compilation between machines of different word sizes is
     somewhat problematic and sometimes does not work.

   Since GNU Pascal generates assembler code, you probably need a
cross-assembler that GNU Pascal can run, in order to produce object
files.  If you want to link on other than the target machine, you need a
cross-linker as well.  You also need header files and libraries suitable
for the target machine that you can install on the host machine.

Steps of Cross-Compilation
--------------------------

   To compile and run a program using a cross-compiler involves several
steps:

   * Run the cross-compiler on the host machine to produce assembler
     files for the target machine.  This requires header files for the
     target machine.

   * Assemble the files produced by the cross-compiler.  You can do this
     either with an assembler on the target machine, or with a
     cross-assembler on the host machine.

   * Link those files to make an executable.  You can do this either
     with a linker on the target machine, or with a cross-linker on the
     host machine.  Whichever machine you use, you need libraries and
     certain startup files (typically `crt....o') for the target
     machine.

   It is most convenient to do all of these steps on the same host
machine, since then you can do it all with a single invocation of GNU
Pascal.  This requires a suitable cross-assembler and cross-linker.
For some targets, the GNU assembler and linker are available.

Configuring GNU CC as a crosscompiler
-------------------------------------

   No special actions have to be taken to configure GNU Pascal as a
crosscompiler. Cross-compiler specific configuration is done only for
GCC.  Section 4.2 of "Using and Porting GNU CC" deals with
cross-configurations in great detail. Once cross-binutils and a C
library for the target machine are in place, GCC can be configured
(from the GCC object directory).  Suppose we are on a FreeBSD system
and want a cross-compiler that produces code that runs on MS-DOS:

     % ../gcc-2.7.2.1/configure --prefix=/usr --target=i386-go32

   This creates all the necessary config files, links and Makefile in
the GCC object directory. Now, proceed with the compilation and
installation process like in the case of the native configuration
described before. Do not remove files from the GCC object directory;
the cross-compiler is used to compile the GNU Pascal runtime system
(RTS) for the target system.

Building the Pascal crosscompiler
---------------------------------

   Once you have verified the C crosscompiler, the Pascal
cross-compiler can be configured and built. Note that the `configure'
script does not require any cross-compiler related switches because GPC
inherits all of this from GNU CC.

   Sample output for a FreeBSD->msdos cross configuration:

     --------------------------------------------------------------------------
     Configuration summary:
       Building a i386-go32 crosscompiler hosted by i386-unknown-freebsd2.1.0
     
       GPC sources in:         ../gpc-2.0
       GCC sources in:         ../gcc-2.7.2.1
       GCC object code in:     ../gcc
       GCC version:            2.7.2.1
     
       Compiler for GPC:       gcc
       Compiler for libgpc.a:  i386-go32-gcc
       Compiler flags:         -g -O
     
       Cross-ar utility:       i386-go32-ar
       Cross-ranlib utility:   i386-go32-ranlib
     
       Installation path:      /usr/bin, /usr/lib/gcc-lib/i386-go32/2.7.2.1
     --------------------------------------------------------------------------
     
     Now, type `make' to build the compiler and runtime system.

   Building a cross-compiler requires cross-binutils for your target,
i386-go32 in this examples. If `configure' is not able to find
`i386-go32-ar' and/or `i386-go32-ranlib', you may have to run it again
with again with `--with-ar=YOUR-CROSS-AR' or
`--with-ranlib=YOUR-CROSS-RANLIB' switches.

   Then, `make' and `make install' the cross-compiler like you would
for a native configuration.

Crossbuilding a compiler.
-------------------------

   Yet another possibility is CROSSBUILDING : Using a crosscompiler to
build GNU Pascal results in a compiler binary that runs on the
cross-target platform. A possible reason why anybody would want to do
this, is when the platform on which you want to run the GNU Pascal
compiler, is not self-hosting. An example is cygwin32.

   To crossbuild GNU Pascal, you have to install a crosscompiler for
your target first. This is covered in chapter 4 of "Using and Porting
GNU CC".  Assuming you want to build a native cygwin32 Pascal compiler
on a FreeBSD system, configure GCC:

     % ../gcc-2.7.2.1/configure --prefix=/usr --build=i386-freebsd \
     	--host=i386-cygwin32 --target=i386-cygwin32

   Build it:

     % make CFLAGS=-O2 LANGUAGES=c

   Now, configure and build GPC. The output of `configure' should look
like:

     --------------------------------------------------------------------------
     Configuration summary:
       Building a i386-cygwin32 crosscompiler hosted by i386-cygwin32
     
       GPC sources in:         ../gpc-2.0
       GCC sources in:         ../gcc-2.7.2.1
       GCC object code in:     ../gcc
       GCC version:            2.7.2.1
     
       Compiler for GPC:       i386-cygwin32-gcc
       Compiler for libgpc.a:  i386-cygwin32-gcc
       Compiler flags:         -g -O
     
       Cross-ar utility:       i386-cygwin32-ar
       Cross-ranlib utility:   i386-cygwin32-ranlib
     
       Installation path:      /usr/bin, /usr/lib/gcc-lib/i386-cygwin32/2.7.2.1
     --------------------------------------------------------------------------
     
     Now, type `make' to build the compiler and runtime system.

   Again, `configure' should be able to detect and configure this setup
without additional flags. If not, specify `--with-ar', `--with-ranlib',
`--with-gcc' and/or `--with-rtsgcc' as appropriate.

   A cross-built compiler must be installed by hand.

Installation instructions for a GPC binary distribution
=======================================================

   To install a binary distribution, cd to the main directory and
unpack the archive while preserving the stored directory structure.  In
concrete, to install a ZIP archive under DOS with PKunzip, type

       C:\> pkunzip -d ARCHIVE

   where ARCHIVE is the name of the distribution file.  To install a
TGZ archive under a UNIX compatible system, become root, then extract
the archive from the root of the filesystem:

       # tar xzf ARCHIVE.tar.gz

   If you are using a `tar' utility other than GNU tar, it might be
necessary to do the above in two steps:

       # gzip -d ARCHIVE.tar.gz
       # tar xf ARCHIVE.tar

   Binary distributions include `libgcc.' and `specs', files that are
normally part of gcc. If you have gcc installed, they will be replaced
unless you manually install the archive.

