[project @ 1997-03-24 06:53:05 by sof]

[ghc-hetmet.git] / docs / installing.lit

%       Building and installing the Glasgow Functional Programming Tools Suite
%
%                               Version 2.02
%                               Feb 1997
                        

\begin{onlystandalone}
\documentstyle[11pt,literate]{article}
\begin{document}
\title{Building and installing the Glasgow Functional Programming Tools Suite\\
Version~2.02}
\author{The GHC Team\\
Department of Computing Science\\
University of Glasgow\\
Glasgow, Scotland\\
G12 8QQ\\
\\
Email: glasgow-haskell-\{users,bugs\}\@dcs.gla.ac.uk}
\maketitle
\begin{rawlatex}
\tableofcontents
\end{rawlatex}
\clearpage
\end{onlystandalone}

This guide is intended for people who want to install or modify
programs from the Glasgow @fptools@ suite (as distinct from those
who merely want to {\em run} them).

The whole install-and-make system has been completely re-done
between GHC 2.01 and 2.02, so it will be worth your while to re-read this guide
even if you have done so before.

\section{Getting the Glasgow @fptools@ suite}

Building the Glasgow tools {\em can} be complicated, mostly because
there are so many permutations of what/why/how, e.g., ``Build Happy
with HBC, everything else with GHC, leave out profiling, and test it
all on the `real' NoFib programs.''  Yeeps!

Happily, such complications don't apply to most people.  A few common
``strategies'' serve most purposes.  Pick one and proceed
as suggested:

\begin{description}
\item[Binary distribution.]  If your only purpose is to install
some of the @fptools@ suite then the easiest thing to do is to
get a binary distribution.  In the binary distribution everything is
pre-compiled for your particular machine architecture and operating
system, so all you should have to do is install the binaries and libraries
in suitable places.  {\em Need pointer to info about doing binary installation.}

A binary distribution may not work for you for two reasons.  
First, we may not have built the suite for the particular
architecture/OS platform you want.  That may be due to lack of time and
energy (in which case you can get a source distribution and build from it;
see below).  Alternatively, it may be because we havn't yet ported the
suite to your architecture, in which case you are considerably worse off.

The second reason a binary distribution may not be what you want is
if you want to read or modify the souce code.

\item[Source distribution.]
You have a supported
platform, but (a)~you like the warm fuzzy feeling of compiling things
yourself; (b)~you want to build something ``extra''---e.g., a set of
libraries with strictness-analysis turned off; or (c)~you want to hack
on GHC yourself.

A source distribution contains complete sources for the @fptools@ suite.
Not only that, but the more awkward machine-independent steps are done
for you.  For example, if you don't have @flex@ you'll it convenient that
the source distribution contains the result of running @flex@ on the
lexical analyser specification.  If you don't want to alter the lexical
analyser then this saves you having to find and install @flex@.
You will still need a working version of GHC on your machine in order to 
compile (most of) the sources, however.


\item[Build GHC from intermediate C \tr{.hc} files:] 
You need a working GHC to use a source distribution. What if you don't have a working GHC?
Then you have no choice but to ``bootstrap'' up from the
intermediate C (\tr{.hc}) files that we provide.
Building GHC on an unsupported platform falls into this category.
Please see \sectionref{booting-from-C}.

NB: For GHC~2.01, bootstrapping from \tr{.hc} files means you will get
an all-2.01 system---possibly unduly slow.  Building with GHC~0.29
will get you a faster compiler...

Once you have built GHC, you can build the other Glasgow tools with
it.

In theory, you can build GHC with another Haskell compiler (e.g.,
HBC).  We havn't tried to do this for ages and it almost certainly
doesn't work any more.

\item[The CVS repository.]
We make source distributions at the same time as binary distributions;
i.e. infrequently.  They should, however, be pretty throughly tested.
If you want more up-to-the minute (but less tested) source code then you 
need to get access to our CVS repository.

All the @fptools@ source code is held in a CVS repository.
CVS is a pretty good source-code control system, and best of all it works over the network.

The repository holds source code only.  It holds no mechanically generated
files at all.  So if you check out a source tree from CVS you will need
to install every utility so that you can build all the derived files
from scratch.

Giving you access to the repository entails some systems administration
at our end; and we are a bit nervous about being submerged in bug reports
about our current working copy (which is, by definition, in flux).  So
we are a bit cautious about offering CVS access.  Feel free to ask though!
\end{description} 

If you are going to do any building from sources (either from a source
distribution or the CVS repository) then you need to read all of this manual in detail.


%************************************************************************
%*                                                                      *
\section{Things to check before you start typing}
%*                                                                      *
%************************************************************************

Here's a list of things to check before you get started.
\begin{enumerate}
\item
\index{disk space needed}
Disk space needed: About 30MB (five hamburgers' worth) of disk space
for the most basic binary distribution of GHC; more for some
platforms, e.g., Alphas.  An extra ``bundle'' (e.g., concurrent
Haskell libraries) might take you to 8--10 hamburgers.

You'll need over 100MB (say, 20 hamburgers' worth) if you need to
build the basic stuff from scratch.

I don't yet know the disk requirements for the non-GHC tools.

All of the above are {\em estimates} of disk-space needs.

\item
Use an appropriate machine, compilers, and things.

SPARC boxes and DEC Alphas running OSF/1 are fully supported.
Linux, MIPS, and HP boxes are in pretty good shape.
\Sectionref{port-info} gives the full run-down on ports or lack
thereof.

\item
Be sure that the ``pre-supposed'' utilities are installed.
Section~\ref{sect_std-utils} elaborates.

\item
If you have any problem when building or installing the Glasgow tools,
please check the ``known pitfalls'' (\sectionref{build-pitfalls}).  If
you feel there is still some shortcoming in our procedure or
instructions, please report it.

For GHC, please see the bug-reporting section of the User's guide
(separate document), to maximise the usefulness of your report.

If in doubt, please send a message to
\tr{glasgow-haskell-bugs@dcs.gla.ac.uk}.
\end{enumerate}


%************************************************************************
%*                                                                      *
\section[port-info]{What machines the Glasgow tools, version~2.01, run on}
\index{ports, GHC}
\index{GHC ports}
\index{supported platforms}
\index{platforms, supported}
%*                                                                      *
%************************************************************************

The main question is whether or not the Haskell compiler (GHC) runs on
your platform.

A ``platform'' is a
architecture/manufacturer/operating-system combination,
such as @sparc-sun-solaris2.5.1@.  Other common ones are
@alpha-dec-osf2@, @hppa1.1-hp-hpux9@, @i386-unknown-linux@,
@i386-unknown-solaris2@, @i386-unknown-freebsd@,
@m68k-sun-sunos4@, @mips-sgi-irix5@,
@sparc-sun-sunos4@, @sparc-sun-solaris2@.

Bear in mind that certain ``bundles'', e.g. parallel Haskell, may not
work on all machines for which basic Haskell compiling is supported.

Some libraries may only work on a limited number of platforms; for
example, a sockets library is of no use unless the operating system
supports the underlying BSDisms.

%************************************************************************
%*                                                                      *
\subsection{What platforms the Haskell compiler (GHC) runs on}
%*                                                                      *
%************************************************************************
\index{fully-supported platforms}
\index{native-code generator}
\index{registerised ports}
\index{unregisterised ports}

The GHC hierarchy of Porting Goodness: (a)~Best is a native-code
generator; (b)~next best is a ``registerised''
port; (c)~the bare minimum is an ``unregisterised'' port.
``Unregisterised'' is so terrible that we won't say more about it.

We use Sun4s running SunOS~4.1.3 and Solaris 2.5, and DEC~Alphas
running OSF/1~V2.0, so those are the ``fully-supported'' platforms,
unsurprisingly.  Both have native-code generators, for quicker
compilations.  The native-code generator for iX86 platforms (e.g.,
Linux ELF) is {\em nearly} working; but is not turned on by default.

Here's everything that's known about GHC ports, as of 2.01. We
identify platforms by their ``canonical GNU-style'' names.

Note that some ports are fussy about which GCC version you use; or
require GAS; or ...

\begin{description}
%-------------------------------------------------------------------
\item[\tr{alpha-dec-osf1}:]
\index{alpha-dec-osf1: fully supported}
(We have OSF/1 V2.0.) Fully supported, including native-code generator.
We recommend GCC 2.6.x or later.

%-------------------------------------------------------------------
\item[\tr{sparc-sun-sunos4}:]
\index{sparc-sun-sunos4: fully supported}
Fully supported, including native-code generator.

%-------------------------------------------------------------------
\item[\tr{sparc-sun-solaris2}:]
\index{sparc-sun-solaris2: fully supported}
Fully supported, including native-code generator.  A couple of quirks,
though: (a)~the profiling libraries are bizarrely huge; (b)~the
default \tr{xargs} program is atrociously bad for building GHC
libraries (see \sectionref{Pre-supposed} for details).

%-------------------------------------------------------------------
\item[HP-PA box running HP/UX 9.x:]
\index{hppa1.1-hp-hpux: registerised port}
Works registerised.  No native-code generator.
For GCC, you're best off with one of the Utah releases of
GCC~2.6.3 (`u3' or later), from \tr{jaguar.cs.utah.edu}.
We think a straight GCC 2.7.x works, too.

Concurrent/Parallel Haskell probably don't work (yet).
\index{hppa1.1-hp-hpux: concurrent---no}
\index{hppa1.1-hp-hpux: parallel---no}

%-------------------------------------------------------------------
\item[\tr{i386-*-linux} (PCs running Linux---ELF format):]
\index{i386-*-linux: registerised port}
GHC~2.01 works registerised.
You {\em must} have GCC 2.7.x or later.
The iX86 native-code generator is {\em nearly} there, but it
isn't turned on by default.

Profiling works, and Concurrent Haskell works.
\index{i386-*-linux: profiling---yes}
\index{i386-*-linux: concurrent---yes}
Parallel Haskell probably works.
\index{i386-*-linux: parallel---maybe}

On old Linux a.out systems: should be the same.
\index{i386-*-linuxaout: registerised port}

%-------------------------------------------------------------------
\item[\tr{i386-*-*bsd} (PCs running FreeBSD (and NetBSD?):]
\index{i386-*-freebsd: registerised port}
GHC~2.01 works registerised. Supports same set of bundles
as the above.

\index{i386-*-freebsd: profiling---yes}
\index{i386-*-freebsd: concurrent---yes}
\index{i386-*-freebsd: parallel---maybe}

%-------------------------------------------------------------------
\item[\tr{i386-unknown-cygwin32}:]
\index{i386-unknown-cygwin32: fully supported}
Fully supported under Win95/NT, including a native
code generator. Requires the @cygwin32@ compatibility library and
a healthy collection of GNU tools (i.e., gcc, GNU ld, bash etc.)
Profiling works, so does Concurrent Haskell. 
\index{i386-*-cygwin32: profiling---yes}
\index{i386-*-cygwin32: concurrent---yes}

% ToDo: more documentation on this is reqd here.

%-------------------------------------------------------------------
\item[\tr{mips-sgi-irix5}:]
\index{mips-sgi-irix5: registerised port}
GHC~2.01 works registerised (no native-code generator).
I suspect any GCC~2.6.x (or later) is OK.  The GCC that I used
was built with \tr{--with-gnu-as}; turns out that is important!

Concurrent/Parallel Haskell probably don't work (yet).
Profiling might work, but it is untested.
\index{mips-sgi-irix5: concurrent---no}
\index{mips-sgi-irix5: parallel---no}
\index{mips-sgi-irix5: profiling---maybe}

%-------------------------------------------------------------------
\item[\tr{m68k-apple-macos7} (Mac, using MPW):]
\index{m68k-apple-macos7: historically ported}
Once upon a time, David Wright in Tasmania has actually
gotten GHC to run on a Macintosh.  Ditto James Thomson here at Glasgow.
You may be able to get Thomson's from here.  (Not sure that it will
excite you to death, but...)

No particularly recent GHC is known to work on a Mac.

%-------------------------------------------------------------------
\item[\tr{m68k-next-nextstep3}:]
\index{m68k-next-nextstep3: historically ported}
Carsten Schultz succeeded with a ``registerised'' port of GHC~0.19.
There's probably a little bit-rot since then, but otherwise it should
still be fine.  Had a report that things were basically OK at 0.22.

Concurrent/Parallel Haskell probably won't work (yet).
\index{m68k-next-nextstep3: concurrent---no}
\index{m68k-next-nextstep3: parallel---no}

%-------------------------------------------------------------------
\item[\tr{m68k-sun-sunos4} (Sun3):]
\index{m68k-sun-sunos4: registerised port}
GHC~2.01 hasn't been tried on a Sun3.  GHC~0.26 worked registerised.
No native-code generator.

Concurrent/Parallel Haskell probably don't work (yet).
\index{m68k-sun-sunos4: concurrent---no}
\index{m68k-sun-sunos4: parallel---no}
\end{description}

%************************************************************************
%*                                                                      *
\subsection{What machines the other tools run on}
%*                                                                      *
%************************************************************************

Unless you hear otherwise, the other tools work if GHC works.

Haggis requires Concurrent Haskell to work.
\index{Haggis, Concurrent Haskell}


%************************************************************************
%*                                                                      *
\section[installing-bin-distrib]{Installing from binary distributions}
\index{binary installations}
\index{installation, of binaries}
%*                                                                      *
%************************************************************************

Installing from binary distributions is easiest, and recommended!
(Why binaries?  Because GHC is a Haskell compiler written in Haskell,
so you've got to ``bootstrap'' it, somehow.  We provide
machine-generated C-files-from-Haskell for this purpose, but it's
really quite a pain to use them.  If you must build GHC from its
sources, using a binary-distributed GHC to do so is a sensible way to
proceed. For the other @fptools@ programs, many are written in Haskell,
so binary distributions allow you to install them without having a Haskell compiler.)


\subsection{Bundle structure}

Binary distributions come in ``bundles,''\index{bundles of binary stuff}
one bundle per file called \tr{<bundle>-<platform>.tar.gz}.
(See Section~\ref{port-info} for what a platform is.)
Suppose that you untar a binary-distribution bundle, thus:
\begin{verbatim}
  % cd /your/scratch/space
  % gunzip < ghc-2.02-sun-sparc-solaris2.tar.gz | tar xvf -
\end{verbatim}
Then you should find a single directory, @fptools@, with the following
structure:
\begin{description}
\item[@Makefile.in@] the raw material from which the @Makefile@ will be made (\sectionref{sect_install}).
\item[@configure@] the configuration script (\sectionref{sect_install}).
\item[@README@] Contains this file summary.
\item[@INSTALL@] Contains this description of how to install the bundle.
\item[@ANNOUNCE-<bundle>@] The announcement message for the bundle.
\item[@NEWS-<bundle>@] release notes for the bundle -- a longer version of @ANNOUNCE@.
\item[@bin/<platform>/@] contains platform-specific executable files to be invoked
directly by the user.  These are the files that must end up in your path.
\item[@lib/<platform>@] contains platform-specific support files for the installation.
Typically there is a subdirectory for each @fptools@ project, whose name is
the name of the project with its version number.
For example, for GHC 2.02 there would be a sub-directory @ghc-2.02/@.

These sub-directories have the following general structure:
\begin{description}
\item[@libHS.a@ etc:] supporting library archives.
\item[@ghc-iface.prl@ etc:] support scripts.
\item[@import/@] Interface files (@.hi@) for the prelude.
\item[@include/@] A few C @#include@ files.
\end{description}

\item[@share/@] contains platform-independent support files for the installation.
Again, there is a sub-directory for each @fptools@ project.

\item[@info/@] contains Emacs info documentation files (one sub-directory per project).
\item[@html/@] contains HTML documentation files (one sub-directory per project).
\item[@man/@] contains Unix manual pages.
\end{description}
This structure is designed so that you can unpack multiple bundles (including
ones from different releases or platforms) into a single @fptools@ directory:
\begin{verbatim}
  % cd /your/scratch/space
  % gunzip < ghc-2.02-sun-sparc-solaris2.tar.gz | tar xvf -
  % gunzip < happy-1.09-sun-sparc-sunos4.tar.gz | tar xvf -
\end{verbatim}
When you do multiple unpacks like this, the top level @Makefile@, @README@,
and @INSTALL@ get overwritten each time.  That's fine -- they should be the same.
Likewise, the @ANNOUNCE-<bundle>@ and @NEWS-<bundle>@ files will be duplicated
across multiple platforms, so they will be harmlessly overwritten when you do 
multiple unpacks.
Finally, the @share/@ stuff will get harmlessly overwritten when you do multiple
unpacks for one bundle on different platforms.

\subsection[sect_install]{Installing}

OK, so let's assume that you have unpacked your chosen bundles into
a scratch directory @fptools@. What next? Well, you will at least need
to run the @configure@ script by changing your directory to @fptools@.
That should convert @Makefile.in@ to @Makefile@.

You can now either start using the tools {\em in-situ} without going
through any installation process, just type @make config@ to set the
tools up for this (you have to be in the @fptools@ directory). You'll
also want to add the path which @make@ echoes to your @PATH@
environment variable. This option is useful if you simply want to try
out the package or you don't have the necessary priviledges (or
inclination) to properly install the tools locally. Note that if you
do decide to install the package `properly' at a later date, you have
to go through the installation steps that 
follows.

To install an @fptools@ package, you'll have to do the following:

\begin{enumerate}
\item Edit the @Makefile@ and check the settings of the following variables:
\begin{description}
\item[@platform@] the platform you are going to install for.
\item[@bindir@] the directory in which to install user-invokable binaries.
\item[@libdir@] the directory in which to install platform-dependent support files.
\item[@datadir@] the directory in which to install platform-independent support files. 
\item[@infodir@] the directory in which to install Emacs info files.
\item[@htmldir@] the directory in which to install HTML documentation.
\item[@dvidir@] the directory in which to install DVI documentation.
\end{description}
The values for these variables can be set through invocation of the
@configure@ script that comes with the distribution, but doing an optical
diff to see if the values match your expectations is always a Good Idea. 

{\em Instead of running @configure@, it is perfectly OK to copy
@Makefile.in@ to @Makefile@ and set all these variables directly
yourself.  But do it right!}

\item Run @make install@.  This {\em  should} works with ordinary Unix
@make@ -- no need for fancy stuff like GNU @make@. 

\item \tr{rehash} (t?csh users), so your shell will see the new stuff
in your bin directory.

\item
Once done, test your ``installation'' as suggested in
\sectionref{GHC_test}.  Be sure to use a \tr{-v} option, so you
can see exactly what pathnames it's using.

If things don't work as expected, check the list of know pitfalls
\sectionref{build-pitfalls}. 
\end{enumerate}

When installing the user-invokable binaries, this installation
procedure will install, say, @GHC@ version 2.02 as @ghc-2.02@.  It
will also make a link (in the binary installation directory) from
@ghc@ to @ghc-2.02@.  If you install multiple versions of GHC then the
last one ``wins'', and ``@ghc@'' will invoke the last one installed.
You can change this manually if you want.  But regardless, @ghc-2.02@
should always invoke @GHC@ version 2.02.

\subsection{What bundles there are}

There are plenty of ``non-basic'' GHC bundles.  The files for them are
called \tr{ghc-2.01-<bundle>-<platform>.tar.gz}, where the
\tr{<platform>} is as above, and \tr{<bundle>} is one of these:
\begin{description}
\item[\tr{prof}:]  Profiling with cost-centres.  You probably want this.

\item[\tr{conc}:] Concurrent Haskell features.  You may want this.

\item[\tr{par}:] Parallel Haskell features (sits on top of PVM).
You'll want this if you're into that kind of thing.

\item[\tr{gran}:] The ``GranSim'' parallel-Haskell simulator
(hmm... mainly for implementors).

\item[\tr{ticky}:] ``Ticky-ticky'' profiling; very detailed
information about ``what happened when I ran this program''---really
for implementors.

\item[\tr{prof-conc}:] Cost-centre profiling for Concurrent Haskell.

\item[\tr{prof-ticky}:]  Ticky-ticky profiling for Concurrent Haskell.
\end{description}

One likely scenario is that you will grab {\em three} binary
bundles---basic, profiling, and concurrent. 



%************************************************************************
%*                                                                      *
\subsection[GHC_test]{Test that GHC seems to be working}
\index{testing a new GHC}
%*                                                                      *
%************************************************************************

The way to do this is, of course, to compile and run {\em this} program
(in a file \tr{Main.hs}):
\begin{verbatim}
main = putStr "Hello, world!\n"
\end{verbatim}

First, give yourself a convenient way to execute the driver script
\tr{ghc/driver/ghc}, perhaps something like...
\begin{verbatim}
% ln -s /local/src/ghc-2.01/ghc/driver/ghc ~/bin/alpha/ghc
% rehash
\end{verbatim}

Compile the program, using the \tr{-v} (verbose) flag to verify that
libraries, etc., are being found properly:
\begin{verbatim}
% ghc -v -o hello Main.hs
\end{verbatim}

Now run it:
\begin{verbatim}
% ./hello
Hello, world!
\end{verbatim}

Some simple-but-profitable tests are to compile and run the
notorious \tr{nfib} program, using different numeric types.  Start
with \tr{nfib :: Int -> Int}, and then try \tr{Integer}, \tr{Float},
\tr{Double}, \tr{Rational} and maybe \tr{Complex Float}.  Code
for this is distributed in \tr{ghc/misc/examples/nfib/}.

For more information on how to ``drive'' GHC,
either do \tr{ghc -help} or consult the User's Guide (distributed in
\tr{ghc/docs/users_guide}).


%************************************************************************
%*                                                                      *
\section[Pre-supposed]{Installing pre-supposed utilities}
\index{pre-supposed utilities}
\index{utilities, pre-supposed}
%*                                                                      *
%************************************************************************

\label{sect_std-utils}

Here are the gory details about some utility programs you may need;
\tr{perl} and \tr{gcc} are the only important ones. (PVM is important
if you're going for Parallel Haskell.) The \tr{configure} script will
tell you if you are missing something.

\begin{description}
\item[Perl:]
\index{pre-supposed: Perl}
\index{Perl, pre-supposed}
{\em You have to have Perl to proceed!} Perl is a language quite good
for doing shell-scripty tasks that involve lots of text processing.
It is pretty easy to install.

Perl~5 is the current version; GHC should be Perl~4 friendly though.
For Win32 platforms, Perl~5 is recommended, we even strongly suggest
you pick up a port of Perl~5 for \tr{cygwin32}, as the common
Hip/ActiveWare port of Perl is not Cool Enough for our purposes.

Perl should be put somewhere so that it can be invoked by the \tr{#!}
script-invoking mechanism. (I believe \tr{/usr/bin/perl} is preferred;
we use \tr{/usr/local/bin/perl} at Glasgow.)  The full pathname should
be less than 32 characters long.

\item[GNU C (\tr{gcc}):]
\index{pre-supposed: GCC (GNU C compiler)}
\index{GCC (GNU C compiler), pre-supposed}
The current version is 2.7.2.  It has a bug that it ticked if you
compile the @gmp@ library without the @-O@ flag.  So the Makefile in
there has the @-O@ flag switched on!  Otherwise, 2.7.2 has no problems that we know of.

If your GCC dies with ``internal error'' on some GHC source file,
please let us know, so we can report it and get things improved.
(Exception: on \tr{iX86} boxes---you may need to fiddle with GHC's
\tr{-monly-N-regs} option; ask if confused...)

\item[PVM version 3:]
\index{pre-supposed: PVM3 (Parallel Virtual Machine)}
\index{PVM3 (Parallel Virtual Machine), pre-supposed}
PVM is the Parallel Virtual Machine on which Parallel Haskell programs
run.  (You only need this if you plan to run Parallel Haskell.  
Concurent Haskell, which runs concurrent threads on a uniprocessor)
doesn't need it.)
Underneath PVM, you can have (for example) a network of
workstations (slow) or a multiprocessor box (faster).

The current version of PVM is 3.3.11; we use 3.3.7.  It is readily available on
the net; I think I got it from \tr{research.att.com}, in \tr{netlib}.

A PVM installation is slightly quirky, but easy to do.  Just follow
the \tr{Readme} instructions.

\item[\tr{xargs} on Solaris2:]
\index{xargs, presupposed (Solaris only)}
\index{Solaris: alternative xargs}
The GHC libraries are put together with something like:
\begin{verbatim}
find bunch-of-dirs -name '*.o' -print | xargs ar q ...
\end{verbatim}
Unfortunately the Solaris \tr{xargs} (the shell-script equivalent
of \tr{map}) only ``bites off'' the \tr{.o} files a few at a
time---with near-infinite rebuilding of the symbol table in
the \tr{.a} file.

The best solution is to install a sane \tr{xargs} from the GNU
findutils distribution.  You can unpack, build, and install the GNU
version in the time the Solaris \tr{xargs} mangles just one GHC
library.

\item[\tr{bash} (Parallel Haskell only):]
\index{bash, presupposed (Parallel Haskell only)}
Sadly, the \tr{gr2ps} script, used to convert ``parallelism profiles''
to PostScript, is written in Bash (GNU's Bourne Again shell).
This bug will be fixed (someday).

\item[Makeindex:]
\index{pre-supposed: makeindex}
\index{makeindex, pre-supposed}
You won't need this unless you are re-making our documents.  Makeindex
normally comes with a \TeX{} distribution, but if not, we can provide
the latest and greatest.

\item[Tgrind:]
\index{pre-supposed: tgrind}
\index{tgrind, pre-supposed}
This is required only if you remake lots of our documents {\em and}
you use the \tr{-t tgrind} option with \tr{lit2latex} (also literate
programming), to do ``fancy'' typesetting of your code.  {\em
Unlikely.}

\item[Flex:]
\index{pre-supposed: flex}
\index{flex, pre-supposed}
This is a quite-a-bit-better-than-Lex lexer.  Used in the
literate-programming stuff.  You won't need it unless you're hacking
on some of our more obscure stuff.

\item[Yacc:]
\index{pre-supposed: non-worthless Yacc}
\index{Yacc, pre-supposed}
If you mess with the Haskell parser, you'll need a Yacc that can cope.
The unbundled \tr{/usr/lang/yacc} is OK; the GNU \tr{bison} is OK;
Berkeley yacc, \tr{byacc}, is not OK.

\item[@sed@]
\index{pre-supposed: sed}
\index{sed, pre-supposed}
You need a working @sed@ if you are going to build from sources.
The build-configuration stuff needs it.
GNU sed version 2.0.4 is no good! It has a bug in it that is tickled by the
build-configuration.  2.0.5 is ok. Others are probably ok too
(assuming we don't create too elaborate configure scripts..)
\end{description}

Two @fptools@ projects are worth a quick note at this point, because
they are useful for all the others:
\begin{itemize}
\item @glafp-utils@ contains several utilities which aren't
particularly Glasgow-ish, but Occasionally Indispensable.


\item @literate@ contains the Glasgow-built tools for generating
documentation.  (The unoriginal idea is to be able to generate @latex@, @info@,
and program code from a single source file.) To get anywhere you'll
need at least @lit2pgm@, either from the @literate@ project, or
because it's already installed on your system. 
\end{itemize}




%************************************************************************
%*                                                                      *
\section{Building from source}
%*                                                                      *
%************************************************************************

You've been rash enough to want to build some of
the Glasgow Functional Programming tools (GHC, Happy,
nofib, etc) from source.  You've slurped the source,
from the CVS repository or from a source distribution, and
now you're sitting looking at a huge mound of bits, wondering
what to do next.

Gingerly, you type @make all@.  Wrong already!

This rest of this guide is intended for duffers like me, who aren't really
interested in Makefiles and systems configurations, but who need
a mental model of the interlocking pieces so that they can 
make them work, extend them consistently when adding new
software, and lay hands on them gently when they don't work.

\subsection{Your source tree}

The source code is held in your {\em source tree}.
The root directory of your source tree {\em must}
contain the following directories and files:
\begin{itemize}
\item @Makefile@: the root Makefile.
\item @mk/@: the directory that contains the
main Makefile code, shared by all the
@fptools@ software.
\item @configure.in@: a file that tells the GNU configuration 
tools what @fptools@ needs to know about the host platform and
operating system. 
\end{itemize}
All the other directories are individual {\em projects} of the
@fptools@ system --- for example, the Glasgow Haskell Compiler (@ghc@),
the Happy parser generator (@happy@), the @nofib@ benchmark suite, 
and so on.
You can have zero or more of these.  Needless to say, some of them
are needed to build others.  For example, you need @happy@ to build
@ghc@.  You can either grab @happy@ too, or else you can use
a version of @happy@ that's already installed on your system, or 
grab a binary distribution of @happy@ and install it.

The important thing to remember is that even if you want only
one project (@happy@, say), you must have a source tree
whose root directory contains @Makefile@, 
@mk/@, @configure.in@, and the project(s) you 
want (@happy/@ in this case).  You cannot get by with 
just the @happy/@ directory.

\subsection{Build trees}

While you can build a system in the source tree, we don't recommend it.
We often want to build multiple versions of our software
for different architectures, or with different options (e.g. profiling).
It's very desirable to share a single copy of the source code among
all these builds.

So for every source tree we have zero or more {\em build trees}.
Each build tree is initially an exact copy of the source tree,
except that each file is a symbolic link to the source file, 
rather than being a copy of the source file.  There are ``standard''
Unix utilities that make such copies, so standard that they go by
different names: @lndir@, @mkshadowdir@ are two.  

The build
tree does not need to be anywhere near the source tree in the
file system.
Indeed, one advantage of separating the build tree from the source
is that the build tree can be placed in a non-backed-up partition,
saving your systems support people from backing up untold megabytes 
of easily-regenerated, and rapidly-changing, gubbins.  The golden rule is 
that (with a single exception -- Section~\ref{sect_build-config})
{\em absolutely
everything in the build tree is either a symbolic link to the source
tree, or else is mechanically generated}.  It should be perfectly 
OK for your build tree to vanish overnight; an hour or two compiling 
and you're on the road again.

You need to be a bit careful, though, that any new files you create
(if you do any development work) are in the source tree, not a build tree!

Remember, that the source files in the build tree are {\em symbolic
links} to the files in the source tree.  (The build tree soon
accumulates lots of built files like @Foo.o@, as well.)  You can {\em
delete} a source file from the build tree without affecting the source
tree (though it's an odd thing to do).  On the other hand, if you {\em
edit} a source file from the build tree, you'll edit the source-tree
file directly.  (You can set up Emacs so that if you edit a source
file from the build tree, Emacs will silently create an edited copy of
the source file in the build tree, leaving the source file unchanged;
but the danger is that you think you've edited the source file whereas
actually all you've done is edit the build-tree copy.  More commonly
you do want to edit the source file.)

Like the source tree, the top level of your build tree must (a linked copy of)
the root directory of the @fptools@ suite.
Inside Makefiles, the root of your build tree is called @$(FPTOOLS_TOP)@.
In the rest of this document path names are relative to @$(FPTOOLS_TOP)@ 
unless otherwise stated.  For example, the file @ghc/mk/target.mk@ is
actually @$(FPTOOLS_TOP)/ghc/mk/target.mk@.


\subsection{Getting the build you want}
\label{sect_build-config}

When you build @fptools@ you will be compiling code 
on a particular {\em host platform},
to run on a particular {\em target platform} (usually the same
as the host platform)\index{platform}.   The difficulty is 
that there are minor differences between different platforms;
minor, but enough that the code needs to be a bit different
for each.  There are some big differences too: for
a different architecture we need to build GHC with a different
native-code generator.

There are also knobs you can turn to control how the @fptools@
software is built.  For example, you might want to build GHC
optimised (so that it runs fast) or unoptimised (so that you can
compile it fast after you've modified it.
Or, you might want to compile it with debugging on (so that
extra consistency-checking code gets included) or off.  And so on.

All of this stuff is called the {\em configuration} of your build.
You set the configuration using an exciting three-step process.
\begin{description}
\item[Step 1: get ready for configuration.]
Change directory to @$(FPTOOLS)@ and issue the following two commands (with no arguments):
\begin{enumerate}
\item @autoconf@. This GNU program
converts @$(FPTOOLS)/configure.in@ to a shell script 
called @$(FPTOOLS)/configure@.

\item @autoheader@.  This second GNU program converts
@$(FPTOOLS)/configure.in@ to @$(FPTOOLS)/mk/config.h.in@.
\end{enumerate}
Both these steps are completely platform-independent; they just mean
that the human-written file (@configure.in@) can be short, although
the resulting shell script, @configure@, and @mk/config.h.in@, are long.

In case you don't have @autoconf@ and @autoheader@ we distribute
the results, @configure@, and @mk/config.h.in@, with the source distribution.
They aren't kept in the repository, though.

\item[Step 2: system configuration.]
Runs the newly-created @configure@ script, thus:
\begin{verbatim}
  ./configure
\end{verbatim}
@configure@'s mission
is to scurry round your computer working out what architecture it has,
what operating system, whether it has the @vfork@ system call,
where @yacc@ is kept, whether @gcc@ is available, where various
obscure @#include@ files are, whether it's a leap year, and
what the systems manager had for lunch.
It communicates these snippets of information in two ways:
\begin{itemize}
\item It translates @mk/config.mk.in@ to @mk/config.mk@,
substituting for things between ``{\tt @@@@}'' brackets.  So,
``{\tt @@HaveGcc@@}'' will be replaced by ``@YES@'' or ``@NO@''
depending on what @configure@ finds.
@mk/config.mk@ is included by every Makefile (directly or indirectly),
so the configuration information is thereby communicated to
all Makefiles.

\item It translates @mk/config.h.in@ to @mk/config.h@.
The latter is @#include@d by various C programs, which
can thereby make use of configuration information.
\end{itemize}


\item[Step 3: build configuration.] Next, you say how this build
of @fptools@ is to differ from the standard defaults by creating a new 
file @mk/build.mk@
{\em in the build tree}.  This file is the one and only
file you edit in the build tree, precisely because it says how
this build differs from the source.  (Just in case your build tree
does die, you might want to keep a private directory of @build.mk@ files,
and use a symbolic link in each build tree to point to the appropriate one.)
So @mk/build.mk@ never
exists in the source tree --- you create one in each build tree
from the template.  We'll discuss what to put in it shortly.
\end{description}
And that's it for configuration. Simple, eh?

What do you put in your build-specific configuration
file @mk/build.mk@?  {\em For almost all purposes all you will do is
put make variable definitions that override those in @mk/config.mk.in@}.
The whole point of @mk/config.mk.in@ --- and its derived 
counterpart @mk/config.mk@ --- is to define the build configuration. It is heavily
commented, as you will see if you look at it.
So generally, what you do is edit @mk/config.mk.in@ (read-only), and add definitions
in @mk/build.mk@ that override any of the @config.mk@ definitions that you
want to change.  (The override occurs because the main boilerplate file,
@mk/boilerplate.mk@, includes @build.mk@ after @config.mk@.)

For example, @config.mk.in@ contains the definition:
\begin{verbatim}
  ProjectsToBuild = glafp-utils literate ghc hslibs
\end{verbatim}
The accompanying comment explains that this is the list of enabled
projects; that is, if (after configuring) you type @gmake all@
in @FPTOOLS_TOP@ three specified projects will be made.
If you want to add @happy@, you can add this line to @build.mk@:
\begin{verbatim}
  ProjectsToBuild += happy
\end{verbatim}
or, if you prefer,
\begin{verbatim}
  ProjectsToBuild = glafp-utils literate ghc hslibs happy
\end{verbatim}
(GNU @make@ allows existing definitions to have new text appended using
the ``@+=@'' operator, which is quite a convenient feature.)

When reading @config.mk.in@, remember that anything between ``{\tt @@...@@}'' signs
is going to be substituted by @configure@ later.  You {\em can} override
the resulting definition if you want, 
but you need to be a bit surer what you are doing.
For example, there's a line that says:
\begin{verbatim}
  YACC = @Yacc@
\end{verbatim}
This defines the Make variables @YACC@ to the pathname for a Yacc that
@configure@ finds somewhere.  If you have your own pet Yacc you want
to use instead, that's fine. Just add this line to @mk/build.mk@:
\begin{verbatim}
  YACC = myyacc
\end{verbatim}
You do not {\em have} to have a @mk/build.mk@ file at all; if you don't,
you'll get all the default settings from @mk/config.mk.in@.


\subsection{The story so far}

Let's summarise the steps you need to carry to get yourself
a fully-configured build tree from scratch.

\begin{enumerate}
\item Get your source tree from somewhere (CVS repository or
source distribution).  Say you call the root directory
@myfptools@ (it does not have to be called @fptools@).

\item Use @lndir@ or @mkshadowdir@ to create a build tree.
\begin{verbatim}
    cd myfptools
    mkshadowdir . /scratch/joe-bloggs/myfptools-sun4
\end{verbatim}
You probably want to give the build tree a name that
suggests its main defining characteristic (in your mind at least),
in case you later add others.

\item Change directory to the build tree.  Everything is going
to happen there now.
\begin{verbatim}
    cd /scratch/joe-bloggs/myfptools-sun4
\end{verbatim}
\item Prepare for system configuration:
\begin{verbatim}
    autoconf
    autoheader
\end{verbatim}
(You can skip this step if you are starting from a source distribution,
and you already have @configure@ and @mk/config.h.in@.)

\item Do system configuration:
\begin{verbatim}
    ./configure
\end{verbatim}

\item Create the file @mk/build.mk@, 
adding definitions for your desired configuration options.
\begin{verbatim}
    emacs mk/build.mk
\end{verbatim}
\end{enumerate}
You can make subsequent changes to @mk/build.mk@ as often 
as you like.  You do not have to run any further configuration 
programs to make these changes take effect.
In theory you should, however, say @gmake clean@, @gmake all@,
because configuration option changes could affect anything --- but in practice you are likely to know what's affected.

\subsection{Making things}

At this point you have made yourself a fully-configured build tree,
so you are ready to start building real things.

The first thing you need to know is that 
{\em you must use GNU @make@, usually called @gmake@, not standard Unix @make@}.
If you use standard Unix @make@ you will get all sorts of error messages
(but no damage) because the @fptools@ @Makefiles@ use GNU @make@'s facilities
extensively.

\subsection[sect_standard-targets]{Standard targets}

In any directory you should be able to make the following:
\begin{description}
\item[@boot@:] does the one-off preparation required to get ready
for the real work.  Notably, it does @gmake depend@ in all directories
that contain programs.  But @boot@ does more.  For example, you can't
do @gmake depend@ in a directory of C program until you have converted
the literate @.lh@ header files into standard @.h@ header files.  Similarly, you convert a literate file to illiterate
form until you have built the @literate@ tools.  @boot@ takes care of these
inter-directory dependencies.

You should say @gmake boot@ right after configuring your build tree.

\item[@all@:] makes all the final target(s) for this Makefile.
Depending on which directory you are in a ``final target''
may be an executable program, a library archive, a shell script,
or a Postscript file.
Typing @gmake@ alone is generally the same as typing @gmake all@.

\item[@install@:] installs the things built by @all@.  Where does it
install them?  That is specified by @mk/config.mk.in@; you can 
override it in @mk/build.mk@.

\item[@uninstall@:] reverses the effect of @install@.

\item[@clean@:] remove all easily-rebuilt files.

\item[@veryclean@:] remove all files that can be rebuilt at all.
There's a danger here that you may remove a file that needs a more
obscure 
utility to rebuild it (especially if you started from a source
distribution).

\item[@check@:] run the test suite.
\end{description}
All of these standard targets
automatically recurse into sub-directories.
Certain other standard targets do not:
\begin{description}
\item[@configure@:] is only available in the root directory @$(FPTOOLS)@;
it has been discussed in Section~\ref{sect_build-config}.

\item[@depend@:] make a @.depend@ file in each directory that needs
it. This @.depend@ file contains mechanically-generated dependency
information; for example, suppose a directory contains a Haskell 
source module @Foo.lhs@ which imports another module @Baz@.
Then the generated @.depend@ file will contain the dependency:
\begin{verbatim}
  Foo.o : Baz.hi
\end{verbatim}
which says that the object file @Foo.o@ depends on the interface
file @Baz.hi@ generated by compiling module @Baz@.
The @.depend@ file is automatically included by every Makefile.

\item[@binary-dist@:] make a binary distribution.

\item[@dist@:] make a source distribution.
\end{description}

\subsection{Other targets}

Most @Makefiles@ have targets other than these.  You can find
this out by looking in the @Makefile@ itself.




%************************************************************************
%*                                                                      *
\section{The @Makefile@ architecture}
%*                                                                      *
%************************************************************************


@make@ is great if everything works --- you type @gmake install@ and, lo,
the right things get compiled and installed in the right places.
Our goal is to make this happen often, but somehow it often doesn't;
instead
some wierd error message eventually emerges from the bowels of a directory
you didn't know existed.

The purpose of this section is to give you a road-map to help you figure
out what is going right and what is going wrong.

\subsection{A small project}

To get started, let us look at the @Makefile@ for an imaginary small
@fptools@ project, @small@.  Each project in @fptools@ has its own
directory in @FPTOOLS_TOP@, so the @small@ project will have its own
directory @FPOOLS_TOP/small/@.  Inside the @small/@ directory there
will be a @Makefile@, looking something like this:
\begin{verbatim}
  #     Makefile for fptools project "small"

  TOP = ..
  include $(TOP)/mk/boilerplate.mk

  SRCS = $(wildcard *.lhs) $(wildcard *.c)
  HS_PROG = small

  include $(TOP)/target.mk
\end{verbatim}
This @Makefile@ has three sections:
\begin{enumerate}
\item The first section includes\footnote{One of the
most important features of GNU @make@ that we use is the ability
for a @Makefile@ to include another named file, very like @cpp@'s @#include@ directive.}
a file of ``boilerplate'' code from the
level above (which in this case will be @FPTOOLS_TOP/mk/boilerplate.mk@).
As its name suggests, @boilerplate.mk@ consists of a large quantity of standard
@Makefile@ code.  We discuss this boilerplate in more detail in Section~\ref{sect_boiler}.

Before the @include@ statement, you must define the @make@ variable
@TOP@ to be the directory containing the @mk@ directory in which
the @boilerplate.mk@ file is.
It is {\em not} OK to simply say
\begin{verbatim}
  include ../mk/boilerplate.mk  # NO NO NO
\end{verbatim}
Why?  Because the @boilerplate.mk@ file needs to know where it is,
so that it can, in turn, @include@ other files.
(Unfortunately, when an @include@d file does an
@include@, the filename is treated
relative to the directory in which @gmake@ is being run, not
the directory in which the @included@ sits.) 
In general,
{\em every file @foo.mk@ 
assumes that @$(TOP)/mk/foo.mk@ refers to itself.}  
It is up to the @Makefile@ doing the @include@ to ensure this
is the case.

Files intended for inclusion in other @Makefile@s are written to have
the following property:
{\em after @foo.mk@ is @include@d, it leaves @TOP@ containing the same
value as it had just before the @include@ statement}.
In our example, this invariant guarantees that the @include@
for @target.mk@ will look in the same directory as that for
@boilerplate.mk@.

\item The second section 
defines the following standard @make@ variables: @SRCS@ (the source files from
which is to be built), and @HS_PROG@ (the
executable binary to be built).  
We will discuss in more detail what the ``standard variables'' are,
and how they affect what happens, in Section~\ref{sect_targets}.

The definition for @SRCS@ uses the useful GNU @make@
construct @$(wildcard@~$pat$@)@, which expands to a list of all the
files matching the pattern $pat$ in the current directory.
In this example, @SRCS@ is set to the list of all the @.lhs@ and @.c@ files
in the directory.  (Let's suppose there is one of each, @Foo.lhs@
and @Baz.c@.)

\item The last section includes a second file of standard code,
called @target.mk@.  It contains the rules that tell @gmake@
how to make the standard targets
(Section~\ref{sect_standard-targets}).
Why, you ask, can't this standard code
be part of @boilerplate.mk@?  Good question.
We discuss the reason later, in Section~\ref{sect_boiler-arch}.

You do not {\em have} to @include@ the @target.mk@ file.  Instead,
you can write rules of your own for all the standard targets.
Usually, though, you will find quite a big payoff from using
the canned rules in
@target.mk@; the price tag is that you have to understand
what canned rules get enabled, and what they do (Section~\ref{sect_targets}).
\end{enumerate}

In our example @Makefile@, most of the work is done 
by the two @include@d files.  When you say @gmake all@,
the following things happen:
\begin{itemize}
\item @gmake@ figures out that the object files are @Foo.o@ and @Baz.o@.
\item It uses a boilerplate pattern rule to compile 
@Foo.lhs@ to @Foo.o@ using
a Haskell compiler.  (Which one?  That is set in the build configuration.)
\item It uses another standard pattern rule to compile @Baz.c@ to @Baz.o@,
using a C compiler.  (Ditto.)
\item It links the resulting @.o@ files together to make @small@,
using the Haskell compiler to do the link step.  (Why not use @ld@?  Because
the Haskell compiler knows what standard librarise to link in.  How did @gmake@
know to use the Haskell compiler to do the link, rather than the C compiler?
Because we set the variable @HS_PROG@ rather than @C_PROG@.)
\end{itemize}
All @Makefile@s should follow the above three-section format.

\subsection{A larger project}

Larger projects are usually structured into a nummber of sub-directories,
each of which has its own @Makefile@.  (In very large projects, this
sub-structure might be iterated recursively, though that is rare.)
To give you the idea, here's part of the directory structure for
the (rather large) @ghc@ project:
\begin{verbatim}
  $(FPTOOLS_TOP)/ghc/
    Makefile

    mk/
      boilerplate.mk
      rules.mk

    docs/
      Makefile
      ...source files for documentation...

    driver/
      Makefile
      ...source files for driver...

    compiler/
      Makefile
      parser/...source files for parser...
      renamer/...source files for renamer...
      ...etc...
\end{verbatim}
The sub-directories @docs@, @driver@, @compiler@, and so on, each contains
a sub-component of @ghc@, and each has its own @Makefile@.
There must also be a @Makefile@ in @$(FPTOOLS_TOP)/ghc@.
It does most of its work by recursively invoking @gmake@
on the @Makefile@s in the sub-directories.
We say that @ghc/Makefile@ is a {\em non-leaf @Makefile@},
because it does little except organise its children, while the @Makefile@s
in the sub-directories are all {\em leaf @Makefile@s}.  (In principle
the sub-directories might themselves contain a non-leaf @Makefile@ and
several sub-sub-directories, but that does not happen in @ghc@.)

The @Makefile@ in @ghc/compiler@ is considered a leaf @Makefile@ even
though the @ghc/compiler@ has sub-directories, because these sub-directories
do not themselves have @Makefile@ in them.  They are just used to structure
the collection of modules that make up @ghc@, but all are managed by the
single @Makefile@ in @ghc/compiler@.

You will notice that @ghc/@ also contains a directory @ghc/mk/@.
It contains @ghc@-specific @Makefile@ boilerplate code.
More precisely:
\begin{itemize}
\item @ghc/mk/boilerplate.mk@ is included at the top of @ghc/Makefile@,
and of all the leaf @Makefile@s in the sub-directories.
It in turn @include@s the main boilerplate file @mk/boilerplate.mk@.

\item @ghc/mk/target.mk@ is @include@d at the bottom of @ghc/Makefile@,
and of all the leaf @Makefiles@ in the sub-directories.
It in turn @include@s the file @mk/target.mk@.
\end{itemize}
So these two files are the place to look for @ghc@-wide customisation
of the standard boilerplate.



\subsection{Boilerplate architecture}
\label{sect_boiler-arch}

Every @Makefile@ includes a @boilerplate.mk@ file at the top,
and @target.mk@ file at the bottom.  In this section we discuss
what is in these files, and why there have to be two of them.
In general:
\begin{itemize}
\item @boilerplate.mk@ consists of:
\begin{itemize}
\item {\em Definitions of millions of @make@ variables} that collectively
specify the build configuration.  Examples: @HC_OPTS@, the options to
feed to the Haskell compiler; @NoFibSubDirs@, the sub-directories to
enable within the @nofib@ project; @GhcWithHc@, the name of the
Haskell compiler to use when compiling @GHC@ in the @ghc@ project.
\item {\em Standard pattern rules} that tell @gmake@ how to construct
one file from another.  
\end{itemize}
@boilerplate.mk@ needs to be @include@d at the {\em top} of each 
@Makefile@, so that the 
user can replace the boilerplate definitions or pattern rules by simply 
giving a new definition or pattern rule in the @Makefile@.  @gmake@ simply
takes the last definition as the definitive one.

Instead of {\em replacing} boilerplate definitions, it is also quite
common to {\em augment} them. For example, a @Makefile@ might say:
\begin{verbatim}
  SRC_HC_OPTS += -O
\end{verbatim}
thereby adding ``@-O@'' to the end of @SRC_HC_OPTS@. 

\item @target.mk@ contains @make@ rules for the standard targets described
in Section~\ref{sect_standard-targets}.
These rules are selectively included, depending on the setting of
certain @make@ variables.  These variables are usually set in the middle
section of the @Makefile@ between the two @include@s.

@target.mk@ must be included at the end (rather than being part of @boilerplate.mk@)
for several tiresome reasons:
\begin{itemize}
\item @gmake@ commits target and dependency lists earlier than it should.
For example, @target.mk@ has a rule that looks like this:
\begin{verbatim}
  $(HS_PROG) : $(OBJS)
        $(HC) $(LD_OPTS) $< -o $@
\end{verbatim}
If this rule was in @boilerplate.mk@ then @$(HS_PROG)@ and @$(OBJS)@
would not have their final values at the moment @gmake@ encountered the
rule.  Alas, @gmake@ takes a snapshot of their current values, and 
wires that snapshot into the rule.
(In contrast, the commands executed when the rule ``fires'' are
only substituted at the moment of firing.)
So, the rule must follow the definitions given in the @Makefile@ itself.

\item Unlike pattern rules, ordinary rules cannot be overriden or
replaced by subsequent rules for the same target (at least not without an
error message).  Including ordinary rules in @boilerplate.mk@ would
prevent the user from writing rules for specific targets in specific cases.

\item There are a couple of other reasons I've forgotten, but it doesn't
matter too much.
\end{itemize}
\end{itemize}

\subsection{The main @mk/boilerplate.mk@ file}
\label{sect_boiler}

If you look at @$(FPTOOLS_TOP)/mk/boilerplate.mk@ you will find that
it consists of the following sections, each held in a separate file:
\begin{description}
\item[@config.mk@] is the build configuration file we discussed at length
in Section~\ref{sect_build-config}.

\item[@paths.mk@] defines @make@ variables for pathnames and file
lists.  In particular, it gives definitions for:
\begin{description}
\item[@SRCS@:] all source files in the current directory.
\item[@HS_SRCS@:] all Haskell source files in the current directory.
It is derived from @$(SRCS)@, so if you override @SRCS@ with a new value
@HS_SRCS@ will follow suit.
\item[@C_SRCS@:] similarly for C source files.
\item[@HS_OBJS@:] the @.o@ files derived from @$(HS_SRCS)@.
\item[@C_OBJS@:] similarly for @$(C_SRCS)@.
\item[@OBJS@:] the concatenation of @$(HS_OBJS)@ and @$(C_OBJS)@.
\end{description}
Any or all of these definitions can easily be overriden by giving new
definitions in your @Makefile@.  For example, 
if there are things in the current directory that look like source files
but aren't, then you'll need to set @SRCS@ manually in your @Makefile@.
The other definitions will then work from this new definition.

What, exactly, does @paths.mk@ consider a ``source file'' to be.
It's based the file's suffix (e.g. @.hs@, @.lhs@, @.c@, @.lc@, etc), 
but this is the kind of detail that changes
more rapidly, so rather than enumerate the source suffices here the best thing
to do is to look in @paths.mk@.

\item[@opts.mk@] defines @make@ variables for option strings to
pass to each program. For example, it defines @HC_OPTS@, the
option strings to pass to the Haskell compiler.  See  \sectionref{sect_suffix}.

\item[@suffix.mk@] defines standard pattern rules -- see \sectionref{sect_suffix}
\end{description}
Any of the variables and pattern rules defined by the boilerplate file
can easily be overridden in any particular @Makefile@, because
the boilerplace @include@ comes first.  Definitions after this
@include@ directive simply override the default ones in @boilerplate.mk@.

\subsection[sect_suffix]{Pattern rules and options}

The file @suffix.mk@ defines standard {\em pattern rules} that say how to build one kind
of file from another, for example, how to build a @.o@ file from a @.c@ file.
(GNU @make@'s {\em pattern rules} are more powerful and easier to use than
Unix @make@'s {\em suffix rules}.)

Almost all the rules look something like this:
\begin{verbatim}
%.o : %.c
        @$(RM) $@
        $(CC) $(CC_OPTS) -c $< -o $@
\end{verbatim}
Here's how to understand the rule.  It says that $something@.o@$ (say @Foo.o@)
can be built from $something@.c@$ (@Foo.c@), by invoking the C compiler
(path name held in @$(CC)@), passing to it the options @$(CC_OPTS)@ and the rule's 
dependent
file of the rule @$<@ (@Foo.c@ in this case), and putting the result in
the rule's target @$@@@ (@Foo.o@ in this case).

Every program is held in a @make@ variable defined in @mk/config.mk@ --- look in @mk/config.mk@ for
the complete list.  One important one is the Haskell compiler, which is called @$(HC)@.

Every programs options are are held in a @make@ variables called @<prog>_OPTS@.
the @<prog>_OPTS@ variables are defined in @mk/opts.mk@.  Almost all of them are defined
like this:
\begin{verbatim}
  CC_OPTS = $(SRC_CC_OPTS) $(WAY$(_way)_CC_OPTS) $($*_CC_OPTS) $(EXTRA_CC_OPTS)
\end{verbatim}
The four variables from which @CC_OPTS@ is built have the following meaning:
\begin{description}
\item[@SRC_CC_OPTS@:] options passed to all C compilations.
\item[@WAY_<way>_CC_OPTS@:] options passed to C compilations for way @<way>@. For example,
@WAY_mp_CC_OPTS@ gives options to pass to the C compiler when compiling way @mp@.
The variable @WAY_CC_OPTS@ holds options to pass to the C compiler when compiling the standard way.
(Section~\ref{sect_ways} dicusses multi-way compilation.)
\item[@<module>_CC_OPTS@:] options to pass to the C compiler that are specific to module @<module>@.
For example, @SMap_CC_OPTS@ gives the specific options to pass to the C compiler when compiling
@SMap.c@.
\item[@EXTRA_CC_OPTS@:] extra options to pass to all C compilations.  This is intended for command
line use, thus;
\begin{verbatim}
  gmake libHS.a EXTRA_CC_OPTS="-v"
\end{verbatim}
\end{description}


\subsection{The main @mk/target.mk@ file}
\label{sect_targets}

@target.mk@ contains canned rules for all the standard targets described in
Section~\ref{sect_standard-targets}.  It is complicated by the fact
that you don't want all of these rules to be active in every @Makefile@.
Rather than have a plethora of tiny files which you can include selectively,
there is a single file, @target.mk@, which selectively includes rules 
based on whether you have defined certain variables in your @Makefile@.
This section explains what rules you get, what variables control them, and 
what the rules do.  Hopefully, you will also get enough of an idea of what is supposed
to happen that you can read and understand any wierd special cases yourself.

\begin{description}
\item{@HS_PROG@.}  If @HS_PROG@ is defined, you get rules with the
following targets:
\begin{description}
\item[@HS_PROG@] itself.  This rule links @$(OBJS)@ with the Haskell
runtime system to get an executable called @$(HS_PROG)@.
\item[@install@] installs @$(HS_PROG)@ in @$(bindir)@ with the execute bit set.
\end{description}

\item[@C_PROG@] is similar to @HS_PROG@, except that the link step
links @$(C_OBJS)@ with the C runtime system.

\item[@LIBRARY@] is similar to @HS_PROG@, except
that it links @$(LIB_OBJS)@ to make the library archive @$(LIBRARY)@,
and @install@ installs it in @$(libdir)@, with the execute bit not set.

\item[@LIB_DATA@] ...
\item[@LIB_EXEC@] ...

\item[@HS_SRCS@, @C_SRCS@.] If @HS_SRCS@ is defined and non-empty, a rule for
the target @depend@ is included, which generates dependency information for
Haskell programs.  Similarly for @C_SRCS@.
\end{description}

All of these rules are ``double-colon'' rules, thus
\begin{verbatim}
  install :: $(HS_PROG)
        ...how to install it...
\end{verbatim}
GNU @make@ treats double-colon rules as separate entities.  If there
are several double-colon rules for the same target it takes each in turn
and fires it if its dependencies say to do so.  This means that you can,
for example, define both @HS_PROG@ and @LIBRARY@, which will generate two
rules for @install@.  When you type @gmake install@ both rules will be fired,
and both the program and the library will be installed, just as you wanted.

\subsection{Recursion}
\label{sect_subdirs}

In leaf @Makefiles@ the variable @SUBDIRS@ is undefined.  In non-leaf
@Makefiles@, @SUBDIRS@ is set to the list of sub-directories that contain subordinate
@Makefile@s.  {\em It is up to you to set @SUBDIRS@ in the @Makefile@.}
There is no automation here --- @SUBDIRS@ is too important automate.

When @SUBDIRS@ is defined, @target.mk@ includes a rather neat rule for
the standard targets (Section~\ref{sect_standard-targets}) that 
simply invokes @make@ recursively in each of the sub-directories.

{\em These recursive invocations are guaranteed to occur in the order in 
which the list of directories is specified in @SUBDIRS@.}  This guarantee can
be important.  For example, when you say @gmake boot@ it can be important
that the recursive invocation of @make boot@ is done in one sub-directory (the include
files, say) before another (the source files).
Generally, put the most independent sub-directory first, and the most dependent
last.

\subsection{Way management}
\label{sect_ways}

We sometimes want to build essentially the same system in several different
``ways''.  For example, we want to build @ghc@'s @Prelude@ libraries with
and without profiling, with and without concurrency, and so on, so that
there is an appropriately-built library archive to link with when the user compiles
his program.
It would be possible to have a completely separate build tree for each such ``way'',
but it would be horribly bureaucratic, especially since often only parts of the
build tree need to be constructed in multiple ways.

Instead, the @template.mk@ contains some clever magic to allow you to build
several versions of a system; and to control locally how many versions are built
and how they differ.  This section explains the magic.

The files for a particular way are distinguished by munging the suffix.
The ``normal way'' is always built, and its files have the standard suffices
@.o@, @.hi@, and so on.  In addition, you can build one or more extra ways,
each distinguished by a {\em way tag}.  The object files and interface files
for one of these extra ways are distinguished by their suffix.  For example,
way @mp@ has files @.mp_o@ and @.mp_hi@.  Library archives have their way
tag the other side of the dot, for boring reasons; thus, @libHS_mp.a@.

A @make@ variable called @way@ holds the current way tag.  {\em @way@ is only ever
set on the command line of a recursive invocation of @gmake@.}  It is
never set inside a @Makefile@.  So it is a global constant for any one invocation
of @gmake@.  Two other @make@ variables, @way_@ and @_way@ are immediately derived
from @$(way)@ and never altered.  If @way@ is not set, then neither are @way_@
and @_way@, and the invocation of @make@ will build the ``normal way''.
If @way@ is set, then the other two variables are set in sympathy. 
For example, if @$(way)@ is ``@mp@'', then @way_@ is set to ``@mp_@''
and @_way@ is set to ``@_mp@''.   These three variables are then used
when constructing file names.

So how does @make@ ever get recursively invoked with @way@ set?  There
are two ways in which this happens:
\begin{itemize}
\item For some (but not all) of the standard targets, when in a leaf sub-directory,
@make@ is recursively invoked for each way tag in @$(WAYS)@.  You set @WAYS@ to
the list of way tags you want these targets built for.  The mechanism here is
very much like the recursive invocation of @make@ in sub-directories
(Section~\ref{sect_subdirs}).

It is up to you to set @WAYS@ in your @Makefile@; this is how you control
what ways will get built.
\item For a useful collection of targets (such as @libHS_mp.a@, @Foo.mp_o@)
there is a rule which recursively invokes @make@ to make the specified
target, setting the @way@ variable.  So if you say @gmake Foo.mp_o@
you should see a recursive invocation @gmake Foo.mp_o way=mp@,
and {\em in this recursive invocation the pattern rule for compiling a Haskell
file into a @.o@ file will match}.  The key pattern rules (in @suffix.mk@)
look like this:
\begin{verbatim}
  %.$(way_)o : %.lhs
        $(HC) $(HC_OPTS) $< -o $@
\end{verbatim}
Neat, eh?
\end{itemize}


\subsection{When the canned rule isn't right}

Sometimes the canned rule just doesn't do the right thing.  For example, in 
the @nofib@ suite we want the link step to print out timing information.
The thing to do here is {\em not} to define @HS_PROG@ or @C_PROG@, and instead
define a special purpose rule in your own @Makefile@.
By using different variable names you will avoid the canned rules being included,
and conflicting with yours.


%************************************************************************
%*                                                                      *
\section[booting-from-C]{Booting/porting from C (\tr{.hc}) files}
\index{building GHC from .hc files}
\index{booting GHC from .hc files}
%*                                                                      *
%************************************************************************

This section is for people trying to get GHC going by using the
supplied intermediate C (\tr{.hc}) files.  This would probably be
because no binaries have been provided, or because the machine
is not ``fully supported.''

THIS SECTION HASN'T BEEN UPDATED YET.  Please let us know if you want to use this
route. Unless someone does, this section may never get written, and the
.hc files distribution may not get built!


%************************************************************************
%*                                                                      *
\section[build-pitfalls]{Known pitfalls in building Glasgow Haskell}
\index{problems, building}
\index{pitfalls, in building}
\index{building pitfalls}
%*                                                                      *
%************************************************************************

WARNINGS about pitfalls and known ``problems'':

\begin{enumerate}
%------------------------------------------------------------------------
\item
One difficulty that comes up from time to time is running out of space
in \tr{/tmp}.  (It is impossible for the configuration stuff to
compensate for the vagaries of different sysadmin approaches re temp
space.)

The quickest way around it is \tr{setenv TMPDIR /usr/tmp} or
even \tr{setenv TMPDIR .} (or the equivalent incantation with the
shell of your choice).

The best way around it is to say
\begin{verbatim}
  TMPDIR=<dir>
\end{verbatim}
in your @build.mk@ file.
Then GHC and the other @fptools@ programs will use the appropriate directory
in all cases.

%------------------------------------------------------------------------
\item
In compiling some support-code bits, e.g., in \tr{ghc/runtime/gmp} and
even in \tr{ghc/lib}, you may get a few C-compiler warnings.  We think
these are OK.

%------------------------------------------------------------------------
\item
When compiling via C, you'll sometimes get ``warning:
assignment from incompatible pointer type'' out of GCC.  Harmless.

%------------------------------------------------------------------------
\item
Similarly, \tr{ar}chiving warning messages like the following are not
a problem:
\begin{verbatim}
ar: filename GlaIOMonad__1_2s.o truncated to GlaIOMonad_
ar: filename GlaIOMonad__2_2s.o truncated to GlaIOMonad_
...
\end{verbatim}

%------------------------------------------------------------------------
\item
Also harmless are some specialisation messages that you may see when
compiling GHC; e.g.:
\begin{verbatim}
SPECIALISATION MESSAGES (Desirable):
*** INSTANCES
{-# SPECIALIZE instance Eq [Class] #-}
{-# SPECIALIZE instance Eq (Class, [Class]) #-}
{-# SPECIALIZE instance Outputable [ClassOp] #-}
{-# SPECIALIZE instance Outputable [Id] #-}
\end{verbatim}

%------------------------------------------------------------------------
\item
In compiling the compiler proper (in \tr{compiler/}), you {\em may} get an
``Out of heap space'' error message.  These
can vary with the vagaries of different systems, it seems.  The
solution is simple: (1)~add a suitable \tr{-H} flag to the @<module>_HC_OPTS@
@make@ variable in the appropriate @Makefile@;
(2)~try again: \tr{gmake}.
(Section~\ref{sect_suffix}.)

Alternatively, just cut to the chase scene:
\begin{verbatim}
% cd ghc/compiler
% make EXTRA_HC_OPTS=-H32m  # or some nice big number
\end{verbatim}

%------------------------------------------------------------------------
\item
Not too long into the build process, you may get a huge complaint
of the form:
\begin{verbatim}
Giant error 'do'ing getopts.pl:  at ./lit2pgm.BOOT line 27.
\end{verbatim}
This indicates that your \tr{perl} was mis-installed; the binary is
unable to find the files for its ``built-in'' library.  Speak to your
perl installer, then re-try.

%------------------------------------------------------------------------
\item
If you try to compile some Haskell, and you get errors from GCC
about lots of things from \tr{/usr/include/math.h}, then your GCC
was mis-installed.  \tr{fixincludes} wasn't run when it should've
been.

As \tr{fixincludes} is now automagically run as part of GCC
installation, this bug also suggests that you have an old GCC.


%------------------------------------------------------------------------
\item
You {\em may} need to re-\tr{ranlib} your libraries (on Sun4s).
\begin{verbatim}
% cd $(libdir)/ghc-2.01/sparc-sun-sunos4
% foreach i ( `find . -name '*.a' -print` ) # or other-shell equiv...
?    ranlib $i
?    # or, on some machines: ar s $i
? end
\end{verbatim}
We'd be interested to know if this is still necessary.

%------------------------------------------------------------------------
\item
If you end up making documents that involve (La)TeX and/or \tr{tib}
(Simon's favourite), the odds are that something about your/our setup
will reach out and bite you.  Yes, please complain; meanwhile,
you can do \tr{make -n whatever.dvi} to see the intended commands,
then try to muddle through, doing them by hand.

\end{enumerate}



% ====================================================================
Here follow pitfalls that apply to pre-2.02 releases.  They should not
happen any more If they do crop up with 2.02 or later, please let us
know.

\begin{enumerate}
%------------------------------------------------------------------------
\item
When configuring the support code (mkworld, glafp-utils, etc.), you
will see mention of \tr{NO_SPECIFIC_PROJECT} and
\tr{NO_SPECIFIC_VERSION}.  This is cool.


%------------------------------------------------------------------------
\item
Sooner or later in your ``make-worlding'' life you will do and see
something like:
\begin{verbatim}
% make Makefile
        rm -f Makefile.bak; mv Makefile Makefile.bak
../.././mkworld/jmake -P ghc -S std -I../.././mkworld -DTopDir=../../. -DTopDir=...
../.././mkworld/jrestoredeps
==== The new Makefile is for: ====
make: Fatal error in reader: Makefile, line 850: Unexpected end of line seen
Current working directory /export/users/fp/grasp/ghc-0.26/ghc/runtimes/standard
*** Error code 1
make: Fatal error: Command failed for target `Makefile'
\end{verbatim}

Don't panic!  It should restore your previous \tr{Makefile}, and
leave the junk one in \tr{Makefile.bad}.  Snoop around at your leisure.

% ------------------------------------------------------------------------
\item
If you do corrupt a \tr{Makefile} totally, or you need to glue a new
directory into the directory structure (in \tr{newdir}---which must
have a \tr{Jmakefile}, even if empty), here's a neat trick:
\begin{verbatim}
#
# move to the directory just above the one where you want a Makefile...
cd ..
#
# make Makefiles, but lie about the directories below...
make Makefiles SUBDIRS=newdir
\end{verbatim}

This will create a \tr{Makefile} {\em ex nihilo} in \tr{newdir}, and
it will be properly wired into the general make-world structure.

% ------------------------------------------------------------------------
\item
Don't configure/build/install using a variety of machines.  A
mistake we've made is to do \tr{make Makefiles} on a Sun4, then try to
build GHC (\tr{make all}) on a Sun3.

%------------------------------------------------------------------------
%\item
%If you build an ``unregisterised'' build, you will get bazillions of
%warnings about `ANSI C forbids braced-groups within expressions'.
%Especially in \tr{ghc/lib}.  These are OK.

\end{enumerate}


\begin{onlystandalone}
\printindex
\end{document}
\end{onlystandalone}