1 <!DOCTYPE Article PUBLIC "-//OASIS//DTD DocBook V3.1//EN">
3 <Article id="building-guide">
7 <Title>Building the Glasgow Functional Programming Tools Suite</Title>
8 <Author><OtherName>The GHC Team</OtherName></Author>
9 <Address><Email>glasgow-haskell-{users,bugs}@haskell.org</Email></Address>
10 <PubDate>November 2001</PubDate>
13 <para>The Glasgow fptools suite is a collection of Functional
14 Programming related tools, including the Glasgow Haskell
15 Compiler (GHC). The source code for the whole suite is kept in
16 a single CVS repository and shares a common build and
17 installation system.</para>
19 <para>This guide is intended for people who want to build or
20 modify programs from the Glasgow <Literal>fptools</Literal>
21 suite (as distinct from those who merely want to
22 <Emphasis>run</Emphasis> them). Installation instructions are
23 now provided in the user guide.</para>
25 <para>The bulk of this guide applies to building on Unix
26 systems; see <XRef LinkEnd="winbuild"> for Windows notes.</para>
32 <sect1 id="sec-getting">
33 <title>Getting the sources</title>
35 <para>You can get your hands on the <literal>fptools</literal>
41 <term><indexterm><primary>Source
42 distributions</primary></indexterm>Source distributions</term>
44 <para>You have a supported platform, but (a) you like
45 the warm fuzzy feeling of compiling things yourself;
46 (b) you want to build something ``extra”—e.g., a
47 set of libraries with strictness-analysis turned off; or
48 (c) you want to hack on GHC yourself.</para>
50 <para>A source distribution contains complete sources for
51 one or more projects in the <literal>fptools</literal>
52 suite. Not only that, but the more awkward
53 machine-independent steps are done for you. For example, if
55 <command>happy</command><indexterm><primary>happy</primary></indexterm>
56 you'll find it convenient that the source distribution
57 contains the result of running <command>happy</command> on
58 the parser specifications. If you don't want to alter the
59 parser then this saves you having to find and install
60 <command>happy</command>. You will still need a working
61 version of GHC (preferably version 4.08+) on your machine in
62 order to compile (most of) the sources, however.</para>
67 <term>The CVS repository.</term>
68 <indexterm><primary>CVS repository</primary>
71 <para>We make releases infrequently. If you want more
72 up-to-the minute (but less tested) source code then you need
73 to get access to our CVS repository.</para>
75 <para>All the <literal>fptools</literal> source code is held
76 in a CVS repository. CVS is a pretty good source-code
77 control system, and best of all it works over the
80 <para>The repository holds source code only. It holds no
81 mechanically generated files at all. So if you check out a
82 source tree from CVS you will need to install every utility
83 so that you can build all the derived files from
86 <para>More information about our CVS repository can be found
87 in <xref linkend="sec-cvs">.</para>
92 <para>If you are going to do any building from sources (either
93 from a source distribution or the CVS repository) then you need to
94 read all of this manual in detail.</para>
98 <title>Using the CVS repository</title>
100 <para>We use <ulink url="http://www.cvshome.org/">CVS</ulink> (Concurrent Version System) to keep track of our
101 sources for various software projects. CVS lets several people
102 work on the same software at the same time, allowing changes to be
103 checked in incrementally. </para>
105 <para>This section is a set of guidelines for how to use our CVS
106 repository, and will probably evolve in time. The main thing to
107 remember is that most mistakes can be undone, but if there's
108 anything you're not sure about feel free to bug the local CVS
109 meister (namely Jeff Lewis
110 <email>jlewis@galconn.com</email>). </para>
112 <sect2 id="cvs-access">
113 <title>Getting access to the CVS Repository</title>
115 <para>You can access the repository in one of two ways:
116 read-only (<xref linkend="cvs-read-only">), or read-write (<xref
117 linkend="cvs-read-write">).</para>
119 <sect3 id="cvs-read-only">
120 <title>Remote Read-only CVS Access</title>
122 <para>Read-only access is available to anyone - there's no
123 need to ask us first. With read-only CVS access you can do
124 anything except commit changes to the repository. You can
125 make changes to your local tree, and still use CVS's merge
126 facility to keep your tree up to date, and you can generate
127 patches using 'cvs diff' in order to send to us for
130 <para>To get read-only access to the repository:</para>
134 <para>Make sure that <application>cvs</application> is
135 installed on your machine.</para>
138 <para>Set your <literal>$CVSROOT</literal> environment variable to
139 <literal>:pserver:anoncvs@glass.cse.ogi.edu:/cvs</literal></para>
142 <para>Run the command</para>
146 <para>The password is simply <literal>cvs</literal>. This
147 sets up a file in your home directory called
148 <literal>.cvspass</literal>, which squirrels away the
149 dummy password, so you only need to do this step once.</para>
153 <para>Now go to <xref linkend="cvs-first">.</para>
158 <sect3 id="cvs-read-write">
159 <title>Remote Read-Write CVS Access</title>
161 <para>We generally supply read-write access to folk doing
162 serious development on some part of the source tree, when
163 going through us would be a pain. If you're developing some
164 feature, or think you have the time and inclination to fix
165 bugs in our sources, feel free to ask for read-write
166 access. There is a certain amount of responsibility that goes
167 with commit privileges; we are more likely to grant you access
168 if you've demonstrated your competence by sending us patches
169 via mail in the past.</para>
171 <para>To get remote read-write CVS access, you need to do the
172 following steps.</para>
176 <para>Make sure that <literal>cvs</literal> and
177 <literal>ssh</literal> are both installed on your
182 <para>Generate a DSA private-key/public-key pair, thus:</para>
186 <para>(<literal>ssh-keygen</literal> comes with
187 <literal>ssh</literal>.) Running <literal>ssh-keygen
188 -d</literal> creates the private and public keys in
189 <literal>$HOME/.ssh/id_dsa</literal> and
190 <literal>$HOME/.ssh/id_dsa.pub</literal> respectively
191 (assuming you accept the standard defaults).</para>
193 <para><literal>ssh-keygen -d</literal> will only work if
194 you have Version 2 <literal>ssh</literal> installed; it
195 will fail harmlessly otherwise. If you only have Version
196 1 you can instead generate an RSA key pair using plain</para>
201 <para>Doing so creates the private and public RSA keys in
202 <literal>$HOME/.ssh/identity</literal> and
203 <literal>$HOME/.ssh/identity.pub</literal>
206 <para>[Deprecated.] Incidentally, you can force a Version
207 2 <literal>ssh</literal> to use the Version 1 protocol by
208 creating <literal>$HOME/config</literal> with the
209 following in it:</para>
217 <para>In both cases, <literal>ssh-keygen</literal> will
218 ask for a <firstterm>passphrase</firstterm>. The
219 passphrase is a password that protects your private key.
220 In response to the 'Enter passphrase' question, you can
224 <para>[Recommended.] Enter a passphrase, which you
225 will quote each time you use CVS.
226 <literal>ssh-agent</literal> makes this entirely
230 <para>[Deprecated.] Just hit return (i.e. use an empty
231 passphrase); then you won't need to quote the
232 passphrase when using CVS. The downside is that
233 anyone who can see into your <literal>.ssh</literal>
234 directory, and thereby get your private key, can mess
235 up the repository. So you must keep the
236 <literal>.ssh</literal> directory with draconian
237 no-access permissions.</para>
243 [Windows users.] The programs <command>ssh-keygen1</command>, <command>ssh1</command>, and <command>cvs</command>,
244 seem to lock up <command>bash</command> entirely if they try to get user input (e.g. if
245 they ask for a password). To solve this, start up <filename>cmd.exe</filename>
246 and run it as follows:
248 c:\tmp> set CYGWIN32=tty
249 c:\tmp> c:/user/local/bin/ssh-keygen1
252 <para>[Windows users.] To protect your
253 <literal>.ssh</literal> from access by anyone else,
254 right-click your <literal>.ssh</literal> directory, and
255 select <literal>Properties</literal>. If you are not on
256 the access control list, add yourself, and give yourself
257 full permissions (the second panel). Remove everyone else
258 from the access control list. Don't leave them there but
259 deny them access, because 'they' may be a list that
261 <para>[March 2003] In fact <command>ssh</command> 3.6.1 now seems to <emphasis>require</emphasis>
262 you to have Unix permissions 600 (read/write for owner only)
263 on the <literal>.ssh/identity</literal> file, else it
264 bombs out. For your local C drive, it seems that <literal>chmod 600 identity</literal> works,
265 but on Windows NT/XP, it doesn't work on a network drive (exact dteails obscure).
266 The solution seems to be to set the CYGWIN environment
267 variable to "<literal>ntsec neta</literal>". The CYGWIN environment variable is discussed
268 in <ulink url="http://cygwin.com/cygwin-ug-net/using-cygwinenv.html">the Cygwin User's Guide</ulink>,
269 and there are more details in <ulink url="http://cygwin.com/faq/faq_4.html#SEC44">the Cygwin FAQ</ulink>.
274 <para>Send a message to to the CVS repository
275 administrator (currently Jeff Lewis
276 <email>jeff@galconn.com</email>), containing:</para>
279 <para>Your desired user-name.</para>
282 <para>Your <literal>.ssh/id_dsa.pub</literal> (or
283 <literal>.ssh/identity.pub</literal>).</para>
286 <para>He will set up your account.</para>
290 <para>Set the following environment variables:</para>
294 <constant>$HOME</constant>: points to your home directory. This is where CVS
295 will look for its <filename>.cvsrc</filename> file.
301 <constant>$CVS_RSH</constant> to <filename>ssh</filename>
303 <para>[Windows users.] Setting your <literal>CVS_RSH</literal> to
304 <literal>ssh</literal> assumes that your CVS client
305 understands how to execute shell script
306 ("#!"s,really), which is what
307 <literal>ssh</literal> is. This may not be the case on
308 Win32 platforms, so in that case set <literal>CVS_RSH</literal> to
309 <literal>ssh1</literal>.</para>
313 <para><literal>$CVSROOT</literal> to
314 <literal>:ext:</literal><replaceable>your-username</replaceable>
315 <literal>@cvs.haskell.org:/home/cvs/root</literal>
316 where <replaceable>your-username</replaceable> is your user name on
317 <literal>cvs.haskell.org</literal>.
319 <para>The <literal>CVSROOT</literal> environment variable will
320 be recorded in the checked-out tree, so you don't need to set
321 this every time. </para>
327 <constant>$CVSEDITOR</constant>: <filename>bin/gnuclient.exe</filename>
328 if you want to use an Emacs buffer for typing in those long commit messages.
334 <constant>$SHELL</constant>: To use bash as the shell in Emacs, you need to
335 set this to point to <filename>bash.exe</filename>.
346 Put the following in <filename>$HOME/.cvsrc</filename>:
357 These are the default options for the specified CVS commands,
358 and represent better defaults than the usual ones. (Feel
359 free to change them.)
363 [Windows users.] Filenames starting with <filename>.</filename> were illegal in
364 the 8.3 DOS filesystem, but that restriction should have
365 been lifted by now (i.e., you're using VFAT or later filesystems.) If
366 you're still having problems creating it, don't worry; <filename>.cvsrc</filename> is entirely
374 <para>[Experts.] Once your account is set up, you can get
375 access from other machines without bothering Jeff, thus:</para>
378 <para>Generate a public/private key pair on the new
382 <para>Use ssh to log in to
383 <literal>cvs.haskell.org</literal>, from your old
387 <para>Add the public key for the new machine to the file
388 <literal>$HOME/ssh/authorized_keys</literal> on
389 <literal>cvs.haskell.org</literal>.
390 (<literal>authorized_keys2</literal>, I think, for Version
394 <para>Make sure that the new version of
395 <literal>authorized_keys</literal> still has 600 file
404 <sect2 id="cvs-first">
405 <title>Checking Out a Source Tree</title>
409 <para>Make sure you set your <literal>CVSROOT</literal>
410 environment variable according to either of the remote
411 methods above. The Approved Way to check out a source tree
412 is as follows:</para>
415 $ cvs checkout fpconfig
418 <para>At this point you have a new directory called
419 <literal>fptools</literal> which contains the basic stuff
420 for the fptools suite, including the configuration files and
421 some other junk. </para>
423 <para>[Windows users.] The following messages appear to be harmless:
425 setsockopt IPTOS_LOWDELAY: Invalid argument
426 setsockopt IPTOS_THROUGHPUT: Invalid argument
431 <para>You can call the fptools directory whatever you like,
432 CVS won't mind: </para>
435 $ mv fptools <replaceable>directory</replaceable>
438 <para> NB: after you've read the CVS manual you might be
439 tempted to try</para>
441 $ cvs checkout -d <replaceable>directory</replaceable> fpconfig
444 <para>instead of checking out <literal>fpconfig</literal>
445 and then renaming it. But this doesn't work, and will
446 result in checking out the entire repository instead of just
447 the <literal>fpconfig</literal> bit.</para>
449 $ cd <replaceable>directory</replaceable>
450 $ cvs checkout ghc hslibs libraries
453 <para>The second command here checks out the relevant
454 modules you want to work on. For a GHC build, for instance,
455 you need at least the <literal>ghc</literal>,
456 <literal>hslibs</literal> and <literal>libraries</literal>
457 modules (for a full list of the projects available, see
458 <xref linkend="projects">).</para>
463 <sect2 id="cvs-committing">
464 <title>Committing Changes</title>
466 <para>This is only if you have read-write access to the
467 repository. For anoncvs users, CVS will issue a "read-only
468 repository" error if you try to commit changes.</para>
472 <para>Build the software, if necessary. Unless you're just
473 working on documentation, you'll probably want to build the
474 software in order to test any changes you make.</para>
478 <para>Make changes. Preferably small ones first.</para>
482 <para>Test them. You can see exactly what changes you've
483 made by using the <literal>cvs diff</literal> command:</para>
487 <para>lists all the changes (using the
488 <literal>diff</literal> command) in and below the current
489 directory. In emacs, <literal>C-c C-v =</literal> runs
490 <literal>cvs diff</literal> on the current buffer and shows
491 you the results.</para>
495 <para>Before checking in a change, you need to update your
502 <para>This pulls in any changes that other people have made,
503 and merges them with yours. If there are any conflicts, CVS
504 will tell you, and you'll have to resolve them before you
505 can check your changes in. The documentation describes what
506 to do in the event of a conflict.</para>
508 <para>It's not always necessary to do a full cvs update
509 before checking in a change, since CVS will always tell you
510 if you try to check in a file that someone else has changed.
511 However, you should still update at regular intervals to
512 avoid making changes that don't work in conjuction with
513 changes that someone else made. Keeping an eye on what goes
514 by on the mailing list can help here.</para>
518 <para>When you're happy that your change isn't going to
519 break anything, check it in. For a one-file change:</para>
522 $ cvs commit <replaceable>filename</replaceable>
525 <para>CVS will then pop up an editor for you to enter a
526 "commit message", this is just a short description
527 of what your change does, and will be kept in the history of
530 <para>If you're using emacs, simply load up the file into a
531 buffer and type <literal>C-x C-q</literal>, and emacs will
532 prompt for a commit message and then check in the file for
535 <para>For a multiple-file change, things are a bit
536 trickier. There are several ways to do this, but this is the
537 way I find easiest. First type the commit message into a
538 temporary file. Then either</para>
541 $ cvs commit -F <replaceable>commit-message</replaceable> <replaceable>file_1</replaceable> .... <replaceable>file_n</replaceable>
544 <para>or, if nothing else has changed in this part of the
548 $ cvs commit -F <replaceable>commit-message</replaceable> <replaceable>directory</replaceable>
551 <para>where <replaceable>directory</replaceable> is a common
552 parent directory for all your changes, and
553 <replaceable>commit-message</replaceable> is the name of the
554 file containing the commit message.</para>
556 <para>Shortly afterwards, you'll get some mail from the
557 relevant mailing list saying which files changed, and giving
558 the commit message. For a multiple-file change, you should
559 still get only <emphasis>one</emphasis> message.</para>
564 <sect2 id="cvs-update">
565 <title>Updating Your Source Tree</title>
567 <para>It can be tempting to cvs update just part of a source
568 tree to bring in some changes that someone else has made, or
569 before committing your own changes. This is NOT RECOMMENDED!
570 Quite often changes in one part of the tree are dependent on
571 changes in another part of the tree (the
572 <literal>mk/*.mk</literal> files are a good example where
573 problems crop up quite often). Having an inconsistent tree is a
574 major cause of headaches. </para>
576 <para>So, to avoid a lot of hassle, follow this recipe for
577 updating your tree: </para>
581 $ cvs update -Pd 2>&1 | tee log</screen>
583 <para>Look at the log file, and fix any conflicts (denoted by a
584 <quote>C</quote> in the first column). If you're using multiple
585 build trees, then for every build tree you have pointing at this
586 source tree, you need to update the links in case any new files
587 have appeared: </para>
590 $ cd <replaceable>build-tree</replaceable>
591 $ lndir <replaceable>source-tree</replaceable>
594 <para>Some files might have been removed, so you need to remove
595 the links pointing to these non-existent files:</para>
598 $ find . -xtype l -exec rm '{}' \;
601 <para>To be <emphasis>really</emphasis> safe, you should do
604 <screen>$ gmake all</screen>
606 <para>from the top-level, to update the dependencies and build
607 any changed files. </para>
610 <sect2 id="cvs-tags">
611 <title>GHC Tag Policy</title>
613 <para>If you want to check out a particular version of GHC,
614 you'll need to know how we tag versions in the repository. The
615 policy (as of 4.04) is:</para>
619 <para>The tree is branched before every major release. The
620 branch tag is <literal>ghc-x-xx-branch</literal>, where
621 <literal>x-xx</literal> is the version number of the release
622 with the <literal>'.'</literal> replaced by a
623 <literal>'-'</literal>. For example, the 4.04 release lives
624 on <literal>ghc-4-04-branch</literal>.</para>
628 <para>The release itself is tagged with
629 <literal>ghc-x-xx</literal> (on the branch). eg. 4.06 is
630 called <literal>ghc-4-06</literal>.</para>
634 <para>We didn't always follow these guidelines, so to see
635 what tags there are for previous versions, do <literal>cvs
636 log</literal> on a file that's been around for a while (like
637 <literal>fptools/ghc/README</literal>).</para>
641 <para>So, to check out a fresh GHC 4.06 tree you would
645 $ cvs co -r ghc-4-06 fpconfig
647 $ cvs co -r ghc-4-06 ghc hslibs
651 <sect2 id="cvs-hints">
652 <title>General Hints</title>
656 <para>As a general rule: commit changes in small units,
657 preferably addressing one issue or implementing a single
658 feature. Provide a descriptive log message so that the
659 repository records exactly which changes were required to
660 implement a given feature/fix a bug. I've found this
661 <emphasis>very</emphasis> useful in the past for finding out
662 when a particular bug was introduced: you can just wind back
663 the CVS tree until the bug disappears.</para>
667 <para>Keep the sources at least *buildable* at any given
668 time. No doubt bugs will creep in, but it's quite easy to
669 ensure that any change made at least leaves the tree in a
670 buildable state. We do nightly builds of GHC to keep an eye
671 on what things work/don't work each day and how we're doing
672 in relation to previous verions. This idea is truely wrecked
673 if the compiler won't build in the first place!</para>
677 <para>To check out extra bits into an already-checked-out
678 tree, use the following procedure. Suppose you have a
679 checked-out fptools tree containing just ghc, and you want
680 to add nofib to it:</para>
691 $ cvs update -d nofib
694 <para>(the -d flag tells update to create a new
695 directory). If you just want part of the nofib suite, you
700 $ cvs checkout nofib/spectral
703 <para>This works because <literal>nofib</literal> is a
704 module in its own right, and spectral is a subdirectory of
705 the nofib module. The path argument to checkout must always
706 start with a module name. There's no equivalent form of this
707 command using <literal>update</literal>.</para>
713 <sect1 id="projects">
714 <title>What projects are there?</title>
716 <para>The <literal>fptools</literal> suite consists of several
717 <firstterm>projects</firstterm>, most of which can be downloaded,
718 built and installed individually. Each project corresponds to a
719 subdirectory in the source tree, and if checking out from CVS then
720 each project can be checked out individually by sitting in the top
721 level of your source tree and typing <command>cvs checkout
722 <replaceable>project</replaceable></command>.</para>
724 <para>Here is a list of the projects currently available:</para>
728 <term><literal>ghc</literal></term>
729 <indexterm><primary><literal>ghc</literal></primary>
730 <secondary>project</secondary></indexterm>
732 <para>The <ulink url="http://www.haskell.org/ghc/">Glasgow
733 Haskell Compiler</ulink> (minus libraries). Absolutely
734 required for building GHC.</para>
739 <term><literal>glafp-utils</literal></term>
740 <indexterm><primary><literal>glafp-utils</literal></primary><secondary>project</secondary></indexterm>
742 <para>Utility programs, some of which are used by the
743 build/installation system. Required for pretty much
749 <term><literal>green-card</literal></term>
750 <indexterm><primary><literal>green-card</literal></primary><secondary>project</secondary></indexterm>
753 url="http://www.haskell.org/greencard/">Green Card</ulink>
754 system for generating Haskell foreign function
760 <term><literal>haggis</literal></term>
761 <indexterm><primary><literal>haggis</literal></primary><secondary>project</secondary></indexterm>
764 url="http://www.dcs.gla.ac.uk/fp/software/haggis/">Haggis</ulink>
765 Haskell GUI framework.</para>
770 <term><literal>haddock</literal></term>
771 <indexterm><primary><literal>haddock</literal></primary><secondary>project</secondary></indexterm>
774 url="http://www.haskell.org/haddock/">Haddock</ulink>
775 documentation tool.</para>
780 <term><literal>happy</literal></term>
781 <indexterm><primary><literal>happy</literal></primary><secondary>project</secondary></indexterm>
784 url="http://www.haskell.org/happy/">Happy</ulink> Parser
790 <term><literal>hdirect</literal></term>
791 <indexterm><primary><literal>hdirect</literal></primary><secondary>project</secondary></indexterm>
794 url="http://www.haskell.org/hdirect/">H/Direct</ulink>
795 Haskell interoperability tool.</para>
800 <term><literal>hood</literal></term>
801 <indexterm><primary><literal>hood</literal></primary><secondary>project</secondary></indexterm>
803 <para>The <ulink url="http://www.haskell.org/hood/">Haskell
804 Object Observation Debugger</ulink>.</para>
809 <term><literal>hslibs</literal></term>
810 <indexterm><primary><literal>hslibs</literal></primary><secondary>project</secondary></indexterm>
812 <para>Supplemental libraries for GHC
813 (<emphasis>required</emphasis> for building GHC).</para>
818 <term><literal>libraries</literal></term>
819 <indexterm><primary><literal></literal></primary><secondary>project</secondary></indexterm>
821 <para>Hierarchical Haskell library suite
822 (<emphasis>required</emphasis> for building GHC).</para>
827 <term><literal>mhms</literal></term>
828 <indexterm><primary><literal></literal></primary><secondary>project</secondary></indexterm>
830 <para>The Modular Haskell Metric System.</para>
835 <term><literal>nofib</literal></term>
836 <indexterm><primary><literal>nofib</literal></primary><secondary>project</secondary></indexterm>
838 <para>The NoFib suite: A collection of Haskell programs used
839 primarily for benchmarking.</para>
844 <term><literal>testsuite</literal></term>
845 <indexterm><primary><literal>testsuite</literal></primary><secondary>project</secondary></indexterm>
847 <para>A testing framework, including GHC's regression test
853 <para>So, to build GHC you need at least the
854 <literal>ghc</literal>, <literal>libraries</literal> and
855 <literal>hslibs</literal> projects (a GHC source distribution will
856 already include the bits you need).</para>
859 <sect1 id="sec-build-checks">
860 <title>Things to check before you start</title>
862 <para>Here's a list of things to check before you get
868 <indexterm><primary>Disk space needed</primary></indexterm>
869 <para>Disk space needed: from about 100Mb for a basic GHC
870 build, up to probably 500Mb for a GHC build with everything
871 included (libraries built several different ways,
876 <para>Use an appropriate machine / operating system. <xref
877 linkend="sec-port-info"> lists the supported platforms; if
878 yours isn't amongst these then you can try porting GHC (see
879 <xref linkend="sec-porting-ghc">).</para>
883 <para>Be sure that the “pre-supposed” utilities are
884 installed. <Xref LinkEnd="sec-pre-supposed">
889 <para>If you have any problem when building or installing the
890 Glasgow tools, please check the “known pitfalls” (<Xref
891 LinkEnd="sec-build-pitfalls">). Also check the FAQ for the
892 version you're building, which is part of the User's Guide and
893 available on the <ulink URL="http://www.haskell.org/ghc/" >GHC web
896 <indexterm><primary>bugs</primary><secondary>known</secondary></indexterm>
898 <para>If you feel there is still some shortcoming in our
899 procedure or instructions, please report it.</para>
901 <para>For GHC, please see the <ulink
902 url="http://www.haskell.org/ghc/docs/latest/set/bug-reporting.html">bug-reporting
903 section of the GHC Users' Guide</ulink>, to maximise the
904 usefulness of your report.</para>
906 <indexterm><primary>bugs</primary><secondary>seporting</secondary></indexterm>
907 <para>If in doubt, please send a message to
908 <email>glasgow-haskell-bugs@haskell.org</email>.
909 <indexterm><primary>bugs</primary><secondary>mailing
910 list</secondary></indexterm></para>
915 <sect1 id="sec-port-info">
916 <title>What machines the Glasgow tools run on</title>
918 <indexterm><primary>ports</primary><secondary>GHC</secondary></indexterm>
919 <indexterm><primary>GHC</primary><secondary>ports</secondary></indexterm>
920 <indexterm><primary>platforms</primary><secondary>supported</secondary></indexterm>
922 <para>The main question is whether or not the Haskell compiler
923 (GHC) runs on your platform.</para>
925 <para>A “platform” is a
926 architecture/manufacturer/operating-system combination, such as
927 <literal>sparc-sun-solaris2</literal>. Other common ones are
928 <literal>alpha-dec-osf2</literal>,
929 <literal>hppa1.1-hp-hpux9</literal>,
930 <literal>i386-unknown-linux</literal>,
931 <literal>i386-unknown-solaris2</literal>,
932 <literal>i386-unknown-freebsd</literal>,
933 <literal>i386-unknown-cygwin32</literal>,
934 <literal>m68k-sun-sunos4</literal>,
935 <literal>mips-sgi-irix5</literal>,
936 <literal>sparc-sun-sunos4</literal>,
937 <literal>sparc-sun-solaris2</literal>,
938 <literal>powerpc-ibm-aix</literal>.</para>
940 <para>Some libraries may only work on a limited number of
941 platforms; for example, a sockets library is of no use unless the
942 operating system supports the underlying BSDisms.</para>
945 <title>What platforms the Haskell compiler (GHC) runs on</title>
947 <indexterm><primary>fully-supported platforms</primary></indexterm>
948 <indexterm><primary>native-code generator</primary></indexterm>
949 <indexterm><primary>registerised ports</primary></indexterm>
950 <indexterm><primary>unregisterised ports</primary></indexterm>
952 <para>The GHC hierarchy of Porting Goodness: (a) Best is a
953 native-code generator; (b) next best is a
954 “registerised” port; (c) the bare minimum is an
955 “unregisterised” port.
956 (“Unregisterised” is so terrible that we won't say
957 more about it).</para>
959 <para>We use Sparcs running Solaris 2.7 and x86 boxes running
960 FreeBSD and Linux, so those are the best supported platforms,
961 unsurprisingly.</para>
963 <para>Here's everything that's known about GHC ports. We
964 identify platforms by their “canonical”
965 CPU/Manufacturer/OS triple.</para>
969 <term>alpha-dec-{osf,linux,freebsd,openbsd,netbsd}:</term>
970 <indexterm><primary>alpha-dec-osf</primary></indexterm>
971 <indexterm><primary>alpha-dec-linux</primary></indexterm>
972 <indexterm><primary>alpha-dec-freebsd</primary></indexterm>
973 <indexterm><primary>alpha-dec-openbsd</primary></indexterm>
974 <indexterm><primary>alpha-dec-netbsd</primary></indexterm>
977 <para>The OSF port is currently working (as of GHC version
978 5.02.1) and well supported. The native code generator is
979 currently non-working. Other operating systems will
980 require some minor porting.</para>
985 <term>sparc-sun-sunos4</term>
986 <indexterm><primary>sparc-sun-sunos4</primary></indexterm>
988 <para>Probably works with minor tweaks, hasn't been tested
994 <term>sparc-sun-solaris2</term>
995 <indexterm><primary>sparc-sun-solaris2</primary></indexterm>
997 <para>Fully supported (at least for Solaris 2.7),
998 including native-code generator.</para>
1003 <term>hppa1.1-hp-hpux (HP-PA boxes running HPUX 9.x)</term>
1004 <indexterm><primary>hppa1.1-hp-hpux</primary></indexterm>
1006 <para>A registerised port is available for version 4.08,
1007 but GHC hasn't been built on that platform since (as far
1008 as we know). No native-code generator.</para>
1013 <term>i386-unknown-linux (PCs running Linux, ELF binary format)</term>
1014 <indexterm><primary>i386-*-linux</primary></indexterm>
1016 <para>GHC works registerised and has a native code
1017 generator. You <Emphasis>must</Emphasis> have GCC 2.7.x
1018 or later. NOTE about <literal>glibc</literal> versions:
1019 GHC binaries built on a system running <literal>glibc
1020 2.0</literal> won't work on a system running
1021 <literal>glibc 2.1</literal>, and vice versa. In general,
1022 don't expect compatibility between
1023 <literal>glibc</literal> versions, even if the shared
1024 library version hasn't changed.</para>
1029 <term>i386-unknown-freebsd (PCs running FreeBSD 2.2 or
1031 <indexterm><primary>i386-unknown-freebsd</primary></indexterm>
1033 <para>GHC works registerised. Pre-built packages are
1034 available in the native package format, so if you just
1035 need binaries you're better off just installing the
1036 package (it might even be on your installation
1042 <term>i386-unknown-openbsd (PCs running OpenBSD)</term>
1043 <indexterm><primary>i386-unknown-openbsd</primary></indexterm>
1045 <para>Supported, with native code generator. Packages are
1046 available through the ports system in the native package
1052 <term>i386-unknown-netbsd (PCs running NetBSD and
1054 <indexterm><primary>i386-unknown-netbsd</primary></indexterm>
1056 <para>Will require some minor porting effort, but should
1057 work registerised.</para>
1062 <term>i386-unknown-mingw32 (PCs running Windows)</term>
1063 <indexterm><primary>i386-unknown-mingw32</primary></indexterm>
1065 <para>Fully supported under Win9x, WinNT, Win2k, and
1066 WinXP. Includes a native code generator. Building from
1067 source requires a recent <ulink
1068 url="http://www.cygwin.com/">Cygwin</ulink> distribution
1069 to be installed.</para>
1074 <term>ia64-unknown-linux</term>
1075 <indexterm><primary>ia64-unknown-linux</primary></indexterm>
1077 <para>GHC currently works unregisterised. A registerised
1078 port is in progress.</para>
1083 <term>mips-sgi-irix5</term>
1084 <indexterm><primary>mips-sgi-irix[5-6]</primary></indexterm>
1086 <para>Port has worked in the past, but hasn't been tested
1087 for some time (and will certainly have rotted in various
1088 ways). As usual, we don't have access to machines and
1089 there hasn't been an overwhelming demand for this port,
1090 but feel free to get in touch.</para>
1095 <term>powerpc-ibm-aix</term>
1096 <indexterm><primary>powerpc-ibm-aix</primary></indexterm>
1098 <para>Port currently doesn't work, needs some minimal
1099 porting effort. As usual, we don't have access to
1100 machines and there hasn't been an overwhelming demand for
1101 this port, but feel free to get in touch.</para>
1106 <term>powerpc-apple-darwin</term>
1107 <indexterm><primary>powerpc-apple-darwin</primary></indexterm>
1109 <para>Supported registerised. No native code
1115 <term>powerpc-apple-linux</term>
1116 <indexterm><primary>powerpc-apple-linux</primary></indexterm>
1118 <para>Not supported (yet).</para>
1123 <para>Various other systems have had GHC ported to them in the
1124 distant past, including various Motorola 68k boxes. The 68k
1125 support still remains, but porting to one of these systems will
1126 certainly be a non-trivial task.</para>
1130 <title>What machines the other tools run on</title>
1132 <para>Unless you hear otherwise, the other tools work if GHC
1138 <sect1 id="sec-pre-supposed">
1139 <title>Installing pre-supposed utilities</title>
1141 <indexterm><primary>pre-supposed utilities</primary></indexterm>
1142 <indexterm><primary>utilities, pre-supposed</primary></indexterm>
1144 <para>Here are the gory details about some utility programs you
1145 may need; <command>perl</command>, <command>gcc</command> and
1146 <command>happy</command> are the only important
1147 ones. (PVM<indexterm><primary>PVM</primary></indexterm> is
1148 important if you're going for Parallel Haskell.) The
1149 <command>configure</command><indexterm><primary>configure</primary></indexterm>
1150 script will tell you if you are missing something.</para>
1156 <indexterm><primary>pre-supposed: GHC</primary></indexterm>
1157 <indexterm><primary>GHC, pre-supposed</primary></indexterm>
1159 <para>GHC is required to build many of the tools, including
1160 GHC itself. If you need to port GHC to your platform
1161 because there isn't a binary distribution of GHC available,
1162 then see <xref linkend="sec-porting-ghc">.</para>
1164 <para>Which version of GHC you need will depend on the
1165 packages you intend to build. GHC itself will normally
1166 build using one of several older versions of itself - check
1167 the announcement or release notes for details.</para>
1173 <indexterm><primary>pre-supposed: Perl</primary></indexterm>
1174 <indexterm><primary>Perl, pre-supposed</primary></indexterm>
1176 <para><emphasis>You have to have Perl to proceed!</emphasis>
1177 Perl version 5 at least is required. GHC has been known to
1178 tickle bugs in Perl, so if you find that Perl crashes when
1179 running GHC try updating (or downgrading) your Perl
1180 installation. Versions of Perl that we use and are known to
1181 be fairly stable are 5.005 and 5.6.1.</para>
1183 <para>For Win32 platforms, you should use the binary
1184 supplied in the InstallShield (copy it to
1185 <filename>/bin</filename>). The Cygwin-supplied Perl seems
1188 <para>Perl should be put somewhere so that it can be invoked
1189 by the <literal>#!</literal> script-invoking
1190 mechanism. The full pathname may need to be less than 32
1191 characters long on some systems.</para>
1196 <term>GNU C (<command>gcc</command>)</term>
1197 <indexterm><primary>pre-supposed: GCC (GNU C
1198 compiler)</primary></indexterm> <indexterm><primary>GCC (GNU C
1199 compiler), pre-supposed</primary></indexterm>
1201 <para>We recommend using GCC version 2.95.2 on all
1202 platforms. Failing that, version 2.7.2 is stable on most
1203 platforms. Earlier versions of GCC can be assumed not to
1204 work, and versions in between 2.7.2 and 2.95.2 (including
1205 <command>egcs</command>) have varying degrees of stability
1206 depending on the platform.</para>
1208 <para>If your GCC dies with “internal error” on
1209 some GHC source file, please let us know, so we can report
1210 it and get things improved. (Exception: on iX86
1211 boxes—you may need to fiddle with GHC's
1212 <option>-monly-N-regs</option> option; see the User's
1218 <term>GNU Make</term>
1219 <indexterm><primary>make</primary><secondary>GNU</secondary>
1222 <para>The fptools build system makes heavy use of features
1223 specific to GNU <command>make</command>, so you must have
1224 this installed in order to build any of the fptools
1231 <indexterm><primary>Happy</primary></indexterm>
1233 <para>Happy is a parser generator tool for Haskell, and is
1234 used to generate GHC's parsers. Happy is written in
1235 Haskell, and is a project in the CVS repository
1236 (<literal>fptools/happy</literal>). It can be built from
1237 source, but bear in mind that you'll need GHC installed in
1238 order to build it. To avoid the chicken/egg problem,
1239 install a binary distribtion of either Happy or GHC to get
1240 started. Happy distributions are available from <ulink
1241 url="http://www.haskell.org/happy/">Happy's Web
1242 Page</ulink>.</para>
1247 <term>Autoconf</term>
1248 <indexterm><primary>pre-supposed: Autoconf</primary></indexterm>
1249 <indexterm><primary>Autoconf, pre-supposed</primary></indexterm>
1251 <para>GNU Autoconf is needed if you intend to build from the
1252 CVS sources, it is <emphasis>not</emphasis> needed if you
1253 just intend to build a standard source distribution.</para>
1255 <para>Autoconf builds the <command>configure</command>
1256 script from <filename>configure.in</filename> and
1257 <filename>aclocal.m4</filename>. If you modify either of
1258 these files, you'll need <command>autoconf</command> to
1259 rebuild <filename>configure</filename>.</para>
1264 <term><command>sed</command></term>
1265 <indexterm><primary>pre-supposed: sed</primary></indexterm>
1266 <indexterm><primary>sed, pre-supposed</primary></indexterm>
1268 <para>You need a working <command>sed</command> if you are
1269 going to build from sources. The build-configuration stuff
1270 needs it. GNU sed version 2.0.4 is no good! It has a bug
1271 in it that is tickled by the build-configuration. 2.0.5 is
1272 OK. Others are probably OK too (assuming we don't create too
1273 elaborate configure scripts.)</para>
1278 <para>One <literal>fptools</literal> project is worth a quick note
1279 at this point, because it is useful for all the others:
1280 <literal>glafp-utils</literal> contains several utilities which
1281 aren't particularly Glasgow-ish, but Occasionally Indispensable.
1282 Like <command>lndir</command> for creating symbolic link
1285 <sect2 id="pre-supposed-gph-tools">
1286 <title>Tools for building parallel GHC (GPH)</title>
1290 <term>PVM version 3:</term>
1291 <indexterm><primary>pre-supposed: PVM3 (Parallel Virtual Machine)</primary></indexterm>
1292 <indexterm><primary>PVM3 (Parallel Virtual Machine), pre-supposed</primary></indexterm>
1294 <para>PVM is the Parallel Virtual Machine on which
1295 Parallel Haskell programs run. (You only need this if you
1296 plan to run Parallel Haskell. Concurent Haskell, which
1297 runs concurrent threads on a uniprocessor doesn't need
1298 it.) Underneath PVM, you can have (for example) a network
1299 of workstations (slow) or a multiprocessor box
1302 <para>The current version of PVM is 3.3.11; we use 3.3.7.
1303 It is readily available on the net; I think I got it from
1304 <literal>research.att.com</literal>, in
1305 <filename>netlib</filename>.</para>
1307 <para>A PVM installation is slightly quirky, but easy to
1308 do. Just follow the <filename>Readme</filename>
1309 instructions.</para>
1314 <term><command>bash</command>:</term>
1315 <indexterm><primary>bash, presupposed (Parallel Haskell only)</primary></indexterm>
1317 <para>Sadly, the <command>gr2ps</command> script, used to
1318 convert “parallelism profiles” to PostScript,
1319 is written in Bash (GNU's Bourne Again shell). This bug
1320 will be fixed (someday).</para>
1326 <sect2 id="pre-supposed-other-tools">
1327 <title>Other useful tools</title>
1332 <indexterm><primary>pre-supposed: flex</primary></indexterm>
1333 <indexterm><primary>flex, pre-supposed</primary></indexterm>
1335 <para>This is a quite-a-bit-better-than-Lex lexer. Used
1336 to build a couple of utilities in
1337 <literal>glafp-utils</literal>. Depending on your
1338 operating system, the supplied <command>lex</command> may
1339 or may not work; you should get the GNU version.</para>
1344 <para>More tools are required if you want to format the documentation
1345 that comes with GHC and other fptools projects. See <xref
1346 linkend="building-docs">.</para>
1350 <sect1 id="sec-building-from-source">
1351 <title>Building from source</title>
1353 <indexterm><primary>Building from source</primary></indexterm>
1354 <indexterm><primary>Source, building from</primary></indexterm>
1356 <para>You've been rash enough to want to build some of the Glasgow
1357 Functional Programming tools (GHC, Happy, nofib, etc.) from
1358 source. You've slurped the source, from the CVS repository or
1359 from a source distribution, and now you're sitting looking at a
1360 huge mound of bits, wondering what to do next.</para>
1362 <para>Gingerly, you type <command>make</command>. Wrong
1365 <para>This rest of this guide is intended for duffers like me, who
1366 aren't really interested in Makefiles and systems configurations,
1367 but who need a mental model of the interlocking pieces so that
1368 they can make them work, extend them consistently when adding new
1369 software, and lay hands on them gently when they don't
1372 <sect2 id="quick-start">
1373 <title>Quick Start</title>
1375 <para>If you are starting from a source distribution, and just
1376 want a completely standard build, then the following should
1379 <screen>$ ./configure
1384 <para>For GHC, this will do a 2-stage bootstrap build of the
1385 compiler, with profiling libraries, and install the
1388 <para>If you want to do anything at all non-standard, or you
1389 want to do some development, read on...</para>
1392 <sect2 id="sec-source-tree">
1393 <title>Your source tree</title>
1395 <para>The source code is held in your <emphasis>source
1396 tree</emphasis>. The root directory of your source tree
1397 <emphasis>must</emphasis> contain the following directories and
1402 <para><filename>Makefile</filename>: the root
1407 <para><filename>mk/</filename>: the directory that contains
1408 the main Makefile code, shared by all the
1409 <literal>fptools</literal> software.</para>
1413 <para><filename>configure.in</filename>,
1414 <filename>config.sub</filename>,
1415 <filename>config.guess</filename>: these files support the
1416 configuration process.</para>
1420 <para><filename>install-sh</filename>.</para>
1424 <para>All the other directories are individual
1425 <emphasis>projects</emphasis> of the <literal>fptools</literal>
1426 system—for example, the Glasgow Haskell Compiler
1427 (<literal>ghc</literal>), the Happy parser generator
1428 (<literal>happy</literal>), the <literal>nofib</literal>
1429 benchmark suite, and so on. You can have zero or more of these.
1430 Needless to say, some of them are needed to build others.</para>
1432 <para>The important thing to remember is that even if you want
1433 only one project (<literal>happy</literal>, say), you must have
1434 a source tree whose root directory contains
1435 <filename>Makefile</filename>, <filename>mk/</filename>,
1436 <filename>configure.in</filename>, and the project(s) you want
1437 (<filename>happy/</filename> in this case). You cannot get by
1438 with just the <filename>happy/</filename> directory.</para>
1442 <title>Build trees</title>
1443 <indexterm><primary>build trees</primary></indexterm>
1444 <indexterm><primary>link trees, for building</primary></indexterm>
1446 <para>If you just want to build the software once on a single
1447 platform, then your source tree can also be your build tree, and
1448 you can skip the rest of this section.</para>
1450 <para>We often want to build multiple versions of our software
1451 for different architectures, or with different options
1452 (e.g. profiling). It's very desirable to share a single copy of
1453 the source code among all these builds.</para>
1455 <para>So for every source tree we have zero or more
1456 <emphasis>build trees</emphasis>. Each build tree is initially
1457 an exact copy of the source tree, except that each file is a
1458 symbolic link to the source file, rather than being a copy of
1459 the source file. There are “standard” Unix
1460 utilities that make such copies, so standard that they go by
1462 <command>lndir</command><indexterm><primary>lndir</primary></indexterm>,
1463 <command>mkshadowdir</command><indexterm><primary>mkshadowdir</primary></indexterm>
1464 are two (If you don't have either, the source distribution
1465 includes sources for the X11
1466 <command>lndir</command>—check out
1467 <filename>fptools/glafp-utils/lndir</filename>). See <Xref
1468 LinkEnd="sec-storysofar"> for a typical invocation.</para>
1470 <para>The build tree does not need to be anywhere near the
1471 source tree in the file system. Indeed, one advantage of
1472 separating the build tree from the source is that the build tree
1473 can be placed in a non-backed-up partition, saving your systems
1474 support people from backing up untold megabytes of
1475 easily-regenerated, and rapidly-changing, gubbins. The golden
1476 rule is that (with a single exception—<XRef
1477 LinkEnd="sec-build-config">) <emphasis>absolutely everything in
1478 the build tree is either a symbolic link to the source tree, or
1479 else is mechanically generated</emphasis>. It should be
1480 perfectly OK for your build tree to vanish overnight; an hour or
1481 two compiling and you're on the road again.</para>
1483 <para>You need to be a bit careful, though, that any new files
1484 you create (if you do any development work) are in the source
1485 tree, not a build tree!</para>
1487 <para>Remember, that the source files in the build tree are
1488 <emphasis>symbolic links</emphasis> to the files in the source
1489 tree. (The build tree soon accumulates lots of built files like
1490 <filename>Foo.o</filename>, as well.) You can
1491 <emphasis>delete</emphasis> a source file from the build tree
1492 without affecting the source tree (though it's an odd thing to
1493 do). On the other hand, if you <emphasis>edit</emphasis> a
1494 source file from the build tree, you'll edit the source-tree
1495 file directly. (You can set up Emacs so that if you edit a
1496 source file from the build tree, Emacs will silently create an
1497 edited copy of the source file in the build tree, leaving the
1498 source file unchanged; but the danger is that you think you've
1499 edited the source file whereas actually all you've done is edit
1500 the build-tree copy. More commonly you do want to edit the
1501 source file.)</para>
1503 <para>Like the source tree, the top level of your build tree
1504 must be (a linked copy of) the root directory of the
1505 <literal>fptools</literal> suite. Inside Makefiles, the root of
1506 your build tree is called
1507 <constant>$(FPTOOLS_TOP)</constant><indexterm><primary>FPTOOLS_TOP</primary></indexterm>.
1508 In the rest of this document path names are relative to
1509 <constant>$(FPTOOLS_TOP)</constant> unless
1510 otherwise stated. For example, the file
1511 <filename>ghc/mk/target.mk</filename> is actually
1512 <filename><constant>$(FPTOOLS_TOP)</constant>/ghc/mk/target.mk</filename>.</para>
1515 <sect2 id="sec-build-config">
1516 <title>Getting the build you want</title>
1518 <para>When you build <literal>fptools</literal> you will be
1519 compiling code on a particular <emphasis>host
1520 platform</emphasis>, to run on a particular <emphasis>target
1521 platform</emphasis> (usually the same as the host
1522 platform)<indexterm><primary>platform</primary></indexterm>.
1523 The difficulty is that there are minor differences between
1524 different platforms; minor, but enough that the code needs to be
1525 a bit different for each. There are some big differences too:
1526 for a different architecture we need to build GHC with a
1527 different native-code generator.</para>
1529 <para>There are also knobs you can turn to control how the
1530 <literal>fptools</literal> software is built. For example, you
1531 might want to build GHC optimised (so that it runs fast) or
1532 unoptimised (so that you can compile it fast after you've
1533 modified it. Or, you might want to compile it with debugging on
1534 (so that extra consistency-checking code gets included) or off.
1537 <para>All of this stuff is called the
1538 <emphasis>configuration</emphasis> of your build. You set the
1539 configuration using a three-step process.</para>
1543 <term>Step 1: get ready for configuration.</term>
1545 <para>NOTE: if you're starting from a source distribution,
1546 rather than CVS sources, you can skip this step.</para>
1548 <para>Change directory to
1549 <constant>$(FPTOOLS_TOP)</constant> and
1551 <command>autoconf</command><indexterm><primary>autoconf</primary></indexterm>
1552 (with no arguments). This GNU program converts
1553 <filename><constant>$(FPTOOLS_TOP)</constant>/configure.in</filename>
1554 to a shell script called
1555 <filename><constant>$(FPTOOLS_TOP)</constant>/configure</filename>.
1558 <para>Some projects, including GHC, have their own
1559 configure script. If there's an
1560 <constant>$(FPTOOLS_TOP)/<project>/configure.in</constant>,
1561 then you need to run <command>autoconf</command> in that
1562 directory too.</para>
1564 <para>Both these steps are completely
1565 platform-independent; they just mean that the
1566 human-written file (<filename>configure.in</filename>) can
1567 be short, although the resulting shell script,
1568 <command>configure</command>, and
1569 <filename>mk/config.h.in</filename>, are long.</para>
1574 <term>Step 2: system configuration.</term>
1576 <para>Runs the newly-created <command>configure</command>
1577 script, thus:</para>
1580 ./configure <optional><parameter>args</parameter></optional>
1583 <para><command>configure</command>'s mission is to scurry
1584 round your computer working out what architecture it has,
1585 what operating system, whether it has the
1586 <Function>vfork</Function> system call, where
1587 <command>yacc</command> is kept, whether
1588 <command>gcc</command> is available, where various obscure
1589 <literal>#include</literal> files are, whether it's a
1590 leap year, and what the systems manager had for lunch. It
1591 communicates these snippets of information in two
1598 <filename>mk/config.mk.in</filename><indexterm><primary>config.mk.in</primary></indexterm>
1600 <filename>mk/config.mk</filename><indexterm><primary>config.mk</primary></indexterm>,
1601 substituting for things between
1602 “<literal>@</literal>” brackets. So,
1603 “<literal>@HaveGcc@</literal>” will be
1604 replaced by “<literal>YES</literal>” or
1605 “<literal>NO</literal>” depending on what
1606 <command>configure</command> finds.
1607 <filename>mk/config.mk</filename> is included by every
1608 Makefile (directly or indirectly), so the
1609 configuration information is thereby communicated to
1610 all Makefiles.</para>
1614 <para> It translates
1615 <filename>mk/config.h.in</filename><indexterm><primary>config.h.in</primary></indexterm>
1617 <filename>mk/config.h</filename><indexterm><primary>config.h</primary></indexterm>.
1618 The latter is <literal>#include</literal>d by
1619 various C programs, which can thereby make use of
1620 configuration information.</para>
1624 <para><command>configure</command> takes some optional
1625 arguments. Use <literal>./configure --help</literal> to
1626 get a list of the available arguments. Here are some of
1627 the ones you might need:</para>
1631 <term><literal>--with-ghc=<parameter>path</parameter></literal></term>
1632 <indexterm><primary><literal>--with-ghc</literal></primary>
1635 <para>Specifies the path to an installed GHC which
1636 you would like to use. This compiler will be used
1637 for compiling GHC-specific code (eg. GHC itself).
1638 This option <emphasis>cannot</emphasis> be specified
1639 using <filename>build.mk</filename> (see later),
1640 because <command>configure</command> needs to
1641 auto-detect the version of GHC you're using. The
1642 default is to look for a compiler named
1643 <literal>ghc</literal> in your path.</para>
1648 <term><literal>--with-hc=<parameter>path</parameter></literal></term>
1649 <indexterm><primary><literal>--with-hc</literal></primary>
1652 <para>Specifies the path to any installed Haskell
1653 compiler. This compiler will be used for compiling
1654 generic Haskell code. The default is to use
1655 <literal>ghc</literal>.</para>
1660 <term><literal>--with-gcc=<parameter>path</parameter></literal></term>
1661 <indexterm><primary><literal>--with-gcc</literal></primary>
1664 <para>Specifies the path to the installed GCC. This
1665 compiler will be used to compile all C files,
1666 <emphasis>except</emphasis> any generated by the
1667 installed Haskell compiler, which will have its own
1668 idea of which C compiler (if any) to use. The
1669 default is to use <literal>gcc</literal>.</para>
1674 <para><command>configure</command> caches the results of
1675 its run in <filename>config.cache</filename>. Quite often
1676 you don't want that; you're running
1677 <command>configure</command> a second time because
1678 something has changed. In that case, simply delete
1679 <filename>config.cache</filename>.</para>
1684 <term>Step 3: build configuration.</term>
1686 <para>Next, you say how this build of
1687 <literal>fptools</literal> is to differ from the standard
1688 defaults by creating a new file
1689 <filename>mk/build.mk</filename><indexterm><primary>build.mk</primary></indexterm>
1690 <emphasis>in the build tree</emphasis>. This file is the
1691 one and only file you edit in the build tree, precisely
1692 because it says how this build differs from the source.
1693 (Just in case your build tree does die, you might want to
1694 keep a private directory of <filename>build.mk</filename>
1695 files, and use a symbolic link in each build tree to point
1696 to the appropriate one.) So
1697 <filename>mk/build.mk</filename> never exists in the
1698 source tree—you create one in each build tree from
1699 the template. We'll discuss what to put in it
1705 <para>And that's it for configuration. Simple, eh?</para>
1707 <para>What do you put in your build-specific configuration file
1708 <filename>mk/build.mk</filename>? <emphasis>For almost all
1709 purposes all you will do is put make variable definitions that
1710 override those in</emphasis>
1711 <filename>mk/config.mk.in</filename>. The whole point of
1712 <filename>mk/config.mk.in</filename>—and its derived
1713 counterpart <filename>mk/config.mk</filename>—is to define
1714 the build configuration. It is heavily commented, as you will
1715 see if you look at it. So generally, what you do is look at
1716 <filename>mk/config.mk.in</filename>, and add definitions in
1717 <filename>mk/build.mk</filename> that override any of the
1718 <filename>config.mk</filename> definitions that you want to
1719 change. (The override occurs because the main boilerplate file,
1720 <filename>mk/boilerplate.mk</filename><indexterm><primary>boilerplate.mk</primary></indexterm>,
1721 includes <filename>build.mk</filename> after
1722 <filename>config.mk</filename>.)</para>
1724 <para>For example, <filename>config.mk.in</filename> contains
1725 the definition:</para>
1728 GhcHcOpts=-O -Rghc-timing
1731 <para>The accompanying comment explains that this is the list of
1732 flags passed to GHC when building GHC itself. For doing
1733 development, it is wise to add <literal>-DDEBUG</literal>, to
1734 enable debugging code. So you would add the following to
1735 <filename>build.mk</filename>:</para>
1737 <para>or, if you prefer,</para>
1740 GhcHcOpts += -DDEBUG
1743 <para>GNU <command>make</command> allows existing definitions to
1744 have new text appended using the “<literal>+=</literal>”
1745 operator, which is quite a convenient feature.)</para>
1747 <para>If you want to remove the <literal>-O</literal> as well (a
1748 good idea when developing, because the turn-around cycle gets a
1749 lot quicker), you can just override
1750 <literal>GhcLibHcOpts</literal> altogether:</para>
1753 GhcHcOpts=-DDEBUG -Rghc-timing
1756 <para>When reading <filename>config.mk.in</filename>, remember
1757 that anything between “@...@” signs is going to be substituted
1758 by <command>configure</command> later. You
1759 <emphasis>can</emphasis> override the resulting definition if
1760 you want, but you need to be a bit surer what you are doing.
1761 For example, there's a line that says:</para>
1767 <para>This defines the Make variables <constant>YACC</constant>
1768 to the pathname for a <command>yacc</command> that
1769 <command>configure</command> finds somewhere. If you have your
1770 own pet <command>yacc</command> you want to use instead, that's
1771 fine. Just add this line to <filename>mk/build.mk</filename>:</para>
1777 <para>You do not <emphasis>have</emphasis> to have a
1778 <filename>mk/build.mk</filename> file at all; if you don't,
1779 you'll get all the default settings from
1780 <filename>mk/config.mk.in</filename>.</para>
1782 <para>You can also use <filename>build.mk</filename> to override
1783 anything that <command>configure</command> got wrong. One place
1784 where this happens often is with the definition of
1785 <constant>FPTOOLS_TOP_ABS</constant>: this
1786 variable is supposed to be the canonical path to the top of your
1787 source tree, but if your system uses an automounter then the
1788 correct directory is hard to find automatically. If you find
1789 that <command>configure</command> has got it wrong, just put the
1790 correct definition in <filename>build.mk</filename>.</para>
1794 <sect2 id="sec-storysofar">
1795 <title>The story so far</title>
1797 <para>Let's summarise the steps you need to carry to get
1798 yourself a fully-configured build tree from scratch.</para>
1802 <para> Get your source tree from somewhere (CVS repository
1803 or source distribution). Say you call the root directory
1804 <filename>myfptools</filename> (it does not have to be
1805 called <filename>fptools</filename>). Make sure that you
1806 have the essential files (see <XRef
1807 LinkEnd="sec-source-tree">).</para>
1812 <para>(Optional) Use <command>lndir</command> or
1813 <command>mkshadowdir</command> to create a build tree.</para>
1817 $ mkshadowdir . /scratch/joe-bloggs/myfptools-sun4
1820 <para>(N.B. <command>mkshadowdir</command>'s first argument
1821 is taken relative to its second.) You probably want to give
1822 the build tree a name that suggests its main defining
1823 characteristic (in your mind at least), in case you later
1828 <para>Change directory to the build tree. Everything is
1829 going to happen there now.</para>
1832 $ cd /scratch/joe-bloggs/myfptools-sun4
1838 <para>Prepare for system configuration:</para>
1844 <para>(You can skip this step if you are starting from a
1845 source distribution, and you already have
1846 <filename>configure</filename> and
1847 <filename>mk/config.h.in</filename>.)</para>
1849 <para>Some projects, including GHC itself, have their own
1850 configure scripts, so it is necessary to run autoconf again
1851 in the appropriate subdirectories. eg:</para>
1854 $ (cd ghc; autoconf)
1859 <para>Do system configuration:</para>
1865 <para>Don't forget to check whether you need to add any
1866 arguments to <literal>configure</literal>; for example, a
1867 common requirement is to specify which GHC to use with
1868 <option>--with-ghc=<replaceable>ghc</replaceable></option>.</para>
1872 <para>Create the file <filename>mk/build.mk</filename>,
1873 adding definitions for your desired configuration
1882 <para>You can make subsequent changes to
1883 <filename>mk/build.mk</filename> as often as you like. You do
1884 not have to run any further configuration programs to make these
1885 changes take effect. In theory you should, however, say
1886 <command>gmake clean</command>, <command>gmake all</command>,
1887 because configuration option changes could affect
1888 anything—but in practice you are likely to know what's
1893 <title>Making things</title>
1895 <para>At this point you have made yourself a fully-configured
1896 build tree, so you are ready to start building real
1899 <para>The first thing you need to know is that <emphasis>you
1900 must use GNU <command>make</command>, usually called
1901 <command>gmake</command>, not standard Unix
1902 <command>make</command></emphasis>. If you use standard Unix
1903 <command>make</command> you will get all sorts of error messages
1904 (but no damage) because the <literal>fptools</literal>
1905 <command>Makefiles</command> use GNU <command>make</command>'s
1906 facilities extensively.</para>
1908 <para>To just build the whole thing, <command>cd</command> to
1909 the top of your <literal>fptools</literal> tree and type
1910 <command>gmake</command>. This will prepare the tree and build
1911 the various projects in the correct order.</para>
1914 <sect2 id="sec-bootstrapping">
1915 <title>Bootstrapping GHC</title>
1917 <para>GHC requires a 2-stage bootstrap in order to provide
1918 full functionality, including GHCi. By a 2-stage bootstrap, we
1919 mean that the compiler is built once using the installed GHC,
1920 and then again using the compiler built in the first stage. You
1921 can also build a stage 3 compiler, but this normally isn't
1922 necessary except to verify that the stage 2 compiler is working
1925 <para>Note that when doing a bootstrap, the stage 1 compiler
1926 must be built, followed by the runtime system and libraries, and
1927 then the stage 2 compiler. The correct ordering is implemented
1928 by the top-level fptools <filename>Makefile</filename>, so if
1929 you want everything to work automatically it's best to start
1930 <command>make</command> from the top of the tree. When building
1931 GHC, the top-level fptools <filename>Makefile</filename> is set
1932 up to do a 2-stage bootstrap by default (when you say
1933 <command>make</command>). Some other targets it supports
1940 <para>Build everything as normal, including the stage 1
1948 <para>Build the stage 2 compiler only.</para>
1955 <para>Build the stage 3 compiler only.</para>
1960 <term>bootstrap</term> <term>bootstrap2</term>
1962 <para>Build stage 1 followed by stage 2.</para>
1967 <term>bootstrap3</term>
1969 <para>Build stages 1, 2 and 3.</para>
1974 <term>install</term>
1976 <para>Install everything, including the compiler built in
1977 stage 2. To override the stage, say <literal>make install
1978 stage=<replaceable>n</replaceable></literal> where
1979 <replaceable>n</replaceable> is the stage to install.</para>
1984 <para>The top-level <filename>Makefile</filename> also arranges
1985 to do the appropriate <literal>make boot</literal> steps (see
1986 below) before actually building anything.</para>
1988 <para>The <literal>stage1</literal>, <literal>stage2</literal>
1989 and <literal>stage3</literal> targets also work in the
1990 <literal>ghc/compiler</literal> directory, but don't forget that
1991 each stage requires its own <literal>make boot</literal> step:
1992 for example, you must do</para>
1994 <screen>$ make boot stage=2</screen>
1996 <para>before <literal>make stage2</literal> in
1997 <literal>ghc/compiler</literal>.</para>
2000 <sect2 id="sec-standard-targets">
2001 <title>Standard Targets</title>
2002 <indexterm><primary>targets, standard makefile</primary></indexterm>
2003 <indexterm><primary>makefile targets</primary></indexterm>
2005 <para>In any directory you should be able to make the following:</para>
2009 <term><literal>boot</literal></term>
2011 <para>does the one-off preparation required to get ready
2012 for the real work. Notably, it does <command>gmake
2013 depend</command> in all directories that contain programs.
2014 It also builds the necessary tools for compilation to
2017 <para>Invoking the <literal>boot</literal> target
2018 explicitly is not normally necessary. From the top-level
2019 <literal>fptools</literal> directory, invoking
2020 <literal>gmake</literal> causes <literal>gmake boot
2021 all</literal> to be invoked in each of the project
2022 subdirectories, in the order specified by
2023 <literal>$(AllTargets)</literal> in
2024 <literal>config.mk</literal>.</para>
2026 <para>If you're working in a subdirectory somewhere and
2027 need to update the dependencies, <literal>gmake
2028 boot</literal> is a good way to do it.</para>
2033 <term><literal>all</literal></term>
2035 <para>makes all the final target(s) for this Makefile.
2036 Depending on which directory you are in a “final
2037 target” may be an executable program, a library
2038 archive, a shell script, or a Postscript file. Typing
2039 <command>gmake</command> alone is generally the same as
2040 typing <command>gmake all</command>.</para>
2045 <term><literal>install</literal></term>
2047 <para>installs the things built by <literal>all</literal>
2048 (except for the documentation). Where does it install
2049 them? That is specified by
2050 <filename>mk/config.mk.in</filename>; you can override it
2051 in <filename>mk/build.mk</filename>, or by running
2052 <command>configure</command> with command-line arguments
2053 like <literal>--bindir=/home/simonpj/bin</literal>; see
2054 <literal>./configure --help</literal> for the full
2060 <term><literal>install-docs</literal></term>
2062 <para>installs the documentation. Otherwise behaves just
2063 like <literal>install</literal>.</para>
2068 <term><literal>uninstall</literal></term>
2070 <para>reverses the effect of
2071 <literal>install</literal>.</para>
2076 <term><literal>clean</literal></term>
2078 <para>Delete all files from the current directory that are
2079 normally created by building the program. Don't delete
2080 the files that record the configuration, or files
2081 generated by <command>gmake boot</command>. Also preserve
2082 files that could be made by building, but normally aren't
2083 because the distribution comes with them.</para>
2088 <term><literal>distclean</literal></term>
2090 <para>Delete all files from the current directory that are
2091 created by configuring or building the program. If you
2092 have unpacked the source and built the program without
2093 creating any other files, <literal>make
2094 distclean</literal> should leave only the files that were
2095 in the distribution.</para>
2100 <term><literal>mostlyclean</literal></term>
2102 <para>Like <literal>clean</literal>, but may refrain from
2103 deleting a few files that people normally don't want to
2109 <term><literal>maintainer-clean</literal></term>
2111 <para>Delete everything from the current directory that
2112 can be reconstructed with this Makefile. This typically
2113 includes everything deleted by
2114 <literal>distclean</literal>, plus more: C source files
2115 produced by Bison, tags tables, Info files, and so
2118 <para>One exception, however: <literal>make
2119 maintainer-clean</literal> should not delete
2120 <filename>configure</filename> even if
2121 <filename>configure</filename> can be remade using a rule
2122 in the <filename>Makefile</filename>. More generally,
2123 <literal>make maintainer-clean</literal> should not delete
2124 anything that needs to exist in order to run
2125 <filename>configure</filename> and then begin to build the
2131 <term><literal>check</literal></term>
2133 <para>run the test suite.</para>
2138 <para>All of these standard targets automatically recurse into
2139 sub-directories. Certain other standard targets do not:</para>
2143 <term><literal>configure</literal></term>
2145 <para>is only available in the root directory
2146 <constant>$(FPTOOLS_TOP)</constant>; it has
2147 been discussed in <XRef
2148 LinkEnd="sec-build-config">.</para>
2153 <term><literal>depend</literal></term>
2155 <para>make a <filename>.depend</filename> file in each
2156 directory that needs it. This <filename>.depend</filename>
2157 file contains mechanically-generated dependency
2158 information; for example, suppose a directory contains a
2159 Haskell source module <filename>Foo.lhs</filename> which
2160 imports another module <literal>Baz</literal>. Then the
2161 generated <filename>.depend</filename> file will contain
2162 the dependency:</para>
2168 <para>which says that the object file
2169 <filename>Foo.o</filename> depends on the interface file
2170 <filename>Baz.hi</filename> generated by compiling module
2171 <literal>Baz</literal>. The <filename>.depend</filename>
2172 file is automatically included by every Makefile.</para>
2177 <term><literal>binary-dist</literal></term>
2179 <para>make a binary distribution. This is the target we
2180 use to build the binary distributions of GHC and
2186 <term><literal>dist</literal></term>
2188 <para>make a source distribution. Note that this target
2189 does “make distclean” as part of its work;
2190 don't use it if you want to keep what you've built.</para>
2195 <para>Most <filename>Makefile</filename>s have targets other
2196 than these. You can discover them by looking in the
2197 <filename>Makefile</filename> itself.</para>
2201 <title>Using a project from the build tree</title>
2203 <para>If you want to build GHC (say) and just use it direct from
2204 the build tree without doing <literal>make install</literal>
2205 first, you can run the in-place driver script:
2206 <filename>ghc/compiler/ghc-inplace</filename>.</para>
2208 <para> Do <emphasis>NOT</emphasis> use
2209 <filename>ghc/compiler/ghc</filename>, or
2210 <filename>ghc/compiler/ghc-5.xx</filename>, as these are the
2211 scripts intended for installation, and contain hard-wired paths
2212 to the installed libraries, rather than the libraries in the
2215 <para>Happy can similarly be run from the build tree, using
2216 <filename>happy/src/happy-inplace</filename>.</para>
2220 <title>Fast Making</title>
2222 <indexterm><primary>fastmake</primary></indexterm>
2223 <indexterm><primary>dependencies, omitting</primary></indexterm>
2224 <indexterm><primary>FAST, makefile variable</primary></indexterm>
2226 <para>Sometimes the dependencies get in the way: if you've made
2227 a small change to one file, and you're absolutely sure that it
2228 won't affect anything else, but you know that
2229 <command>make</command> is going to rebuild everything anyway,
2230 the following hack may be useful:</para>
2236 <para>This tells the make system to ignore dependencies and just
2237 build what you tell it to. In other words, it's equivalent to
2238 temporarily removing the <filename>.depend</filename> file in
2239 the current directory (where <command>mkdependHS</command> and
2240 friends store their dependency information).</para>
2242 <para>A bit of history: GHC used to come with a
2243 <command>fastmake</command> script that did the above job, but
2244 GNU make provides the features we need to do it without
2245 resorting to a script. Also, we've found that fastmaking is
2246 less useful since the advent of GHC's recompilation checker (see
2247 the User's Guide section on "Separate Compilation").</para>
2251 <sect1 id="sec-makefile-arch">
2252 <title>The <filename>Makefile</filename> architecture</title>
2253 <indexterm><primary>makefile architecture</primary></indexterm>
2255 <para><command>make</command> is great if everything
2256 works—you type <command>gmake install</command> and lo! the
2257 right things get compiled and installed in the right places. Our
2258 goal is to make this happen often, but somehow it often doesn't;
2259 instead some weird error message eventually emerges from the
2260 bowels of a directory you didn't know existed.</para>
2262 <para>The purpose of this section is to give you a road-map to
2263 help you figure out what is going right and what is going
2267 <title>Debugging</title>
2269 <para>Debugging <filename>Makefile</filename>s is something of a
2270 black art, but here's a couple of tricks that we find
2271 particularly useful. The following command allows you to see
2272 the contents of any make variable in the context of the current
2273 <filename>Makefile</filename>:</para>
2275 <screen>$ make show VALUE=HS_SRCS</screen>
2277 <para>where you can replace <literal>HS_SRCS</literal> with the
2278 name of any variable you wish to see the value of.</para>
2280 <para>GNU make has a <option>-d</option> option which generates
2281 a dump of the decision procedure used to arrive at a conclusion
2282 about which files should be recompiled. Sometimes useful for
2283 tracking down problems with superfluous or missing
2284 recompilations.</para>
2288 <title>A small project</title>
2290 <para>To get started, let us look at the
2291 <filename>Makefile</filename> for an imaginary small
2292 <literal>fptools</literal> project, <literal>small</literal>.
2293 Each project in <literal>fptools</literal> has its own directory
2294 in <constant>FPTOOLS_TOP</constant>, so the
2295 <literal>small</literal> project will have its own directory
2296 <constant>FPOOLS_TOP/small/</constant>. Inside the
2297 <filename>small/</filename> directory there will be a
2298 <filename>Makefile</filename>, looking something like
2301 <indexterm><primary>Makefile, minimal</primary></indexterm>
2304 # Makefile for fptools project "small"
2307 include $(TOP)/mk/boilerplate.mk
2309 SRCS = $(wildcard *.lhs) $(wildcard *.c)
2312 include $(TOP)/target.mk
2315 <para>this <filename>Makefile</filename> has three
2320 <para>The first section includes
2323 One of the most important
2324 features of GNU <command>make</command> that we use is the ability for a <filename>Makefile</filename> to
2325 include another named file, very like <command>cpp</command>'s <literal>#include</literal>
2330 a file of “boilerplate” code from the level
2331 above (which in this case will be
2332 <filename><constant>FPTOOLS_TOP</constant>/mk/boilerplate.mk</filename><indexterm><primary>boilerplate.mk</primary></indexterm>).
2333 As its name suggests, <filename>boilerplate.mk</filename>
2334 consists of a large quantity of standard
2335 <filename>Makefile</filename> code. We discuss this
2336 boilerplate in more detail in <XRef LinkEnd="sec-boiler">.
2337 <indexterm><primary>include, directive in
2338 Makefiles</primary></indexterm> <indexterm><primary>Makefile
2339 inclusion</primary></indexterm></para>
2341 <para>Before the <literal>include</literal> statement, you
2342 must define the <command>make</command> variable
2343 <constant>TOP</constant><indexterm><primary>TOP</primary></indexterm>
2344 to be the directory containing the <filename>mk</filename>
2345 directory in which the <filename>boilerplate.mk</filename>
2346 file is. It is <emphasis>not</emphasis> OK to simply say</para>
2349 include ../mk/boilerplate.mk # NO NO NO
2353 <para>Why? Because the <filename>boilerplate.mk</filename>
2354 file needs to know where it is, so that it can, in turn,
2355 <literal>include</literal> other files. (Unfortunately,
2356 when an <literal>include</literal>d file does an
2357 <literal>include</literal>, the filename is treated relative
2358 to the directory in which <command>gmake</command> is being
2359 run, not the directory in which the
2360 <literal>include</literal>d sits.) In general,
2361 <emphasis>every file <filename>foo.mk</filename> assumes
2363 <filename><constant>$(TOP)</constant>/mk/foo.mk</filename>
2364 refers to itself.</emphasis> It is up to the
2365 <filename>Makefile</filename> doing the
2366 <literal>include</literal> to ensure this is the case.</para>
2368 <para>Files intended for inclusion in other
2369 <filename>Makefile</filename>s are written to have the
2370 following property: <emphasis>after
2371 <filename>foo.mk</filename> is <literal>include</literal>d,
2372 it leaves <constant>TOP</constant> containing the same value
2373 as it had just before the <literal>include</literal>
2374 statement</emphasis>. In our example, this invariant
2375 guarantees that the <literal>include</literal> for
2376 <filename>target.mk</filename> will look in the same
2377 directory as that for <filename>boilerplate.mk</filename>.</para>
2381 <para> The second section defines the following standard
2382 <command>make</command> variables:
2383 <constant>SRCS</constant><indexterm><primary>SRCS</primary></indexterm>
2384 (the source files from which is to be built), and
2385 <constant>HS_PROG</constant><indexterm><primary>HS_PROG</primary></indexterm>
2386 (the executable binary to be built). We will discuss in
2387 more detail what the “standard variables” are,
2388 and how they affect what happens, in <XRef
2389 LinkEnd="sec-targets">.</para>
2391 <para>The definition for <constant>SRCS</constant> uses the
2392 useful GNU <command>make</command> construct
2393 <literal>$(wildcard $pat$)</literal><indexterm><primary>wildcard</primary></indexterm>,
2394 which expands to a list of all the files matching the
2395 pattern <literal>pat</literal> in the current directory. In
2396 this example, <constant>SRCS</constant> is set to the list
2397 of all the <filename>.lhs</filename> and
2398 <filename>.c</filename> files in the directory. (Let's
2399 suppose there is one of each, <filename>Foo.lhs</filename>
2400 and <filename>Baz.c</filename>.)</para>
2404 <para>The last section includes a second file of standard
2406 <filename>target.mk</filename><indexterm><primary>target.mk</primary></indexterm>.
2407 It contains the rules that tell <command>gmake</command> how
2408 to make the standard targets (<Xref
2409 LinkEnd="sec-standard-targets">). Why, you ask, can't this
2410 standard code be part of
2411 <filename>boilerplate.mk</filename>? Good question. We
2412 discuss the reason later, in <Xref
2413 LinkEnd="sec-boiler-arch">.</para>
2415 <para>You do not <emphasis>have</emphasis> to
2416 <literal>include</literal> the
2417 <filename>target.mk</filename> file. Instead, you can write
2418 rules of your own for all the standard targets. Usually,
2419 though, you will find quite a big payoff from using the
2420 canned rules in <filename>target.mk</filename>; the price
2421 tag is that you have to understand what canned rules get
2422 enabled, and what they do (<Xref
2423 LinkEnd="sec-targets">).</para>
2427 <para>In our example <filename>Makefile</filename>, most of the
2428 work is done by the two <literal>include</literal>d files. When
2429 you say <command>gmake all</command>, the following things
2434 <para><command>gmake</command> figures out that the object
2435 files are <filename>Foo.o</filename> and
2436 <filename>Baz.o</filename>.</para>
2440 <para>It uses a boilerplate pattern rule to compile
2441 <filename>Foo.lhs</filename> to <filename>Foo.o</filename>
2442 using a Haskell compiler. (Which one? That is set in the
2443 build configuration.)</para>
2447 <para>It uses another standard pattern rule to compile
2448 <filename>Baz.c</filename> to <filename>Baz.o</filename>,
2449 using a C compiler. (Ditto.)</para>
2453 <para>It links the resulting <filename>.o</filename> files
2454 together to make <literal>small</literal>, using the Haskell
2455 compiler to do the link step. (Why not use
2456 <command>ld</command>? Because the Haskell compiler knows
2457 what standard libraries to link in. How did
2458 <command>gmake</command> know to use the Haskell compiler to
2459 do the link, rather than the C compiler? Because we set the
2460 variable <constant>HS_PROG</constant> rather than
2461 <constant>C_PROG</constant>.)</para>
2465 <para>All <filename>Makefile</filename>s should follow the above
2466 three-section format.</para>
2470 <title>A larger project</title>
2472 <para>Larger projects are usually structured into a number of
2473 sub-directories, each of which has its own
2474 <filename>Makefile</filename>. (In very large projects, this
2475 sub-structure might be iterated recursively, though that is
2476 rare.) To give you the idea, here's part of the directory
2477 structure for the (rather large) GHC project:</para>
2487 ...source files for documentation...
2490 ...source files for driver...
2493 parser/...source files for parser...
2494 renamer/...source files for renamer...
2498 <para>The sub-directories <filename>docs</filename>,
2499 <filename>driver</filename>, <filename>compiler</filename>, and
2500 so on, each contains a sub-component of GHC, and each has its
2501 own <filename>Makefile</filename>. There must also be a
2502 <filename>Makefile</filename> in
2503 <filename><constant>$(FPTOOLS_TOP)</constant>/ghc</filename>.
2504 It does most of its work by recursively invoking
2505 <command>gmake</command> on the <filename>Makefile</filename>s
2506 in the sub-directories. We say that
2507 <filename>ghc/Makefile</filename> is a <emphasis>non-leaf
2508 <filename>Makefile</filename></emphasis>, because it does little
2509 except organise its children, while the
2510 <filename>Makefile</filename>s in the sub-directories are all
2511 <emphasis>leaf <filename>Makefile</filename>s</emphasis>. (In
2512 principle the sub-directories might themselves contain a
2513 non-leaf <filename>Makefile</filename> and several
2514 sub-sub-directories, but that does not happen in GHC.)</para>
2516 <para>The <filename>Makefile</filename> in
2517 <filename>ghc/compiler</filename> is considered a leaf
2518 <filename>Makefile</filename> even though the
2519 <filename>ghc/compiler</filename> has sub-directories, because
2520 these sub-directories do not themselves have
2521 <filename>Makefile</filename>s in them. They are just used to
2522 structure the collection of modules that make up GHC, but all
2523 are managed by the single <filename>Makefile</filename> in
2524 <filename>ghc/compiler</filename>.</para>
2526 <para>You will notice that <filename>ghc/</filename> also
2527 contains a directory <filename>ghc/mk/</filename>. It contains
2528 GHC-specific <filename>Makefile</filename> boilerplate code.
2529 More precisely:</para>
2533 <para><filename>ghc/mk/boilerplate.mk</filename> is included
2534 at the top of <filename>ghc/Makefile</filename>, and of all
2535 the leaf <filename>Makefile</filename>s in the
2536 sub-directories. It in turn <literal>include</literal>s the
2537 main boilerplate file
2538 <filename>mk/boilerplate.mk</filename>.</para>
2542 <para><filename>ghc/mk/target.mk</filename> is
2543 <literal>include</literal>d at the bottom of
2544 <filename>ghc/Makefile</filename>, and of all the leaf
2545 <filename>Makefile</filename>s in the sub-directories. It
2546 in turn <literal>include</literal>s the file
2547 <filename>mk/target.mk</filename>.</para>
2551 <para>So these two files are the place to look for GHC-wide
2552 customisation of the standard boilerplate.</para>
2555 <sect2 id="sec-boiler-arch">
2556 <title>Boilerplate architecture</title>
2557 <indexterm><primary>boilerplate architecture</primary></indexterm>
2559 <para>Every <filename>Makefile</filename> includes a
2560 <filename>boilerplate.mk</filename><indexterm><primary>boilerplate.mk</primary></indexterm>
2561 file at the top, and
2562 <filename>target.mk</filename><indexterm><primary>target.mk</primary></indexterm>
2563 file at the bottom. In this section we discuss what is in these
2564 files, and why there have to be two of them. In general:</para>
2568 <para><filename>boilerplate.mk</filename> consists of:</para>
2572 <para><emphasis>Definitions of millions of
2573 <command>make</command> variables</emphasis> that
2574 collectively specify the build configuration. Examples:
2575 <constant>HC_OPTS</constant><indexterm><primary>HC_OPTS</primary></indexterm>,
2576 the options to feed to the Haskell compiler;
2577 <constant>NoFibSubDirs</constant><indexterm><primary>NoFibSubDirs</primary></indexterm>,
2578 the sub-directories to enable within the
2579 <literal>nofib</literal> project;
2580 <constant>GhcWithHc</constant><indexterm><primary>GhcWithHc</primary></indexterm>,
2581 the name of the Haskell compiler to use when compiling
2582 GHC in the <literal>ghc</literal> project.</para>
2586 <para><emphasis>Standard pattern rules</emphasis> that
2587 tell <command>gmake</command> how to construct one file
2588 from another.</para>
2592 <para><filename>boilerplate.mk</filename> needs to be
2593 <literal>include</literal>d at the <emphasis>top</emphasis>
2594 of each <filename>Makefile</filename>, so that the user can
2595 replace the boilerplate definitions or pattern rules by
2596 simply giving a new definition or pattern rule in the
2597 <filename>Makefile</filename>. <command>gmake</command>
2598 simply takes the last definition as the definitive one.</para>
2600 <para>Instead of <emphasis>replacing</emphasis> boilerplate
2601 definitions, it is also quite common to
2602 <emphasis>augment</emphasis> them. For example, a
2603 <filename>Makefile</filename> might say:</para>
2609 <para>thereby adding “<option>-O</option>” to
2611 <constant>SRC_HC_OPTS</constant><indexterm><primary>SRC_HC_OPTS</primary></indexterm>.</para>
2615 <para><filename>target.mk</filename> contains
2616 <command>make</command> rules for the standard targets
2617 described in <Xref LinkEnd="sec-standard-targets">. These
2618 rules are selectively included, depending on the setting of
2619 certain <command>make</command> variables. These variables
2620 are usually set in the middle section of the
2621 <filename>Makefile</filename> between the two
2622 <literal>include</literal>s.</para>
2624 <para><filename>target.mk</filename> must be included at the
2625 end (rather than being part of
2626 <filename>boilerplate.mk</filename>) for several tiresome
2632 <para><command>gmake</command> commits target and
2633 dependency lists earlier than it should. For example,
2634 <FIlename>target.mk</FIlename> has a rule that looks
2638 $(HS_PROG) : $(OBJS)
2639 $(HC) $(LD_OPTS) $< -o $@
2642 <para>If this rule was in
2643 <filename>boilerplate.mk</filename> then
2644 <constant>$(HS_PROG)</constant><indexterm><primary>HS_PROG</primary></indexterm>
2646 <constant>$(OBJS)</constant><indexterm><primary>OBJS</primary></indexterm>
2647 would not have their final values at the moment
2648 <command>gmake</command> encountered the rule. Alas,
2649 <command>gmake</command> takes a snapshot of their
2650 current values, and wires that snapshot into the rule.
2651 (In contrast, the commands executed when the rule
2652 “fires” are only substituted at the moment
2653 of firing.) So, the rule must follow the definitions
2654 given in the <filename>Makefile</filename> itself.</para>
2658 <para>Unlike pattern rules, ordinary rules cannot be
2659 overriden or replaced by subsequent rules for the same
2660 target (at least, not without an error message).
2661 Including ordinary rules in
2662 <filename>boilerplate.mk</filename> would prevent the
2663 user from writing rules for specific targets in specific
2668 <para>There are a couple of other reasons I've
2669 forgotten, but it doesn't matter too much.</para>
2676 <sect2 id="sec-boiler">
2677 <title>The main <filename>mk/boilerplate.mk</filename> file</title>
2678 <indexterm><primary>boilerplate.mk</primary></indexterm>
2680 <para>If you look at
2681 <filename><constant>$(FPTOOLS_TOP)</constant>/mk/boilerplate.mk</filename>
2682 you will find that it consists of the following sections, each
2683 held in a separate file:</para>
2687 <term><filename>config.mk</filename></term>
2688 <indexterm><primary>config.mk</primary></indexterm>
2690 <para>is the build configuration file we discussed at
2691 length in <Xref LinkEnd="sec-build-config">.</para>
2696 <term><filename>paths.mk</filename></term>
2697 <indexterm><primary>paths.mk</primary></indexterm>
2699 <para>defines <command>make</command> variables for
2700 pathnames and file lists. This file contains code for
2701 automatically compiling lists of source files and deriving
2702 lists of object files from those. The results can be
2703 overriden in the <filename>Makefile</filename>, but in
2704 most cases the automatic setup should do the right
2707 <para>The following variables may be set in the
2708 <filename>Makefile</filename> to affect how the automatic
2709 source file search is done:</para>
2713 <term><literal>ALL_DIRS</literal></term>
2714 <indexterm><primary><literal>ALL_DIRS</literal></primary>
2717 <para>Set to a list of directories to search in
2718 addition to the current directory for source
2724 <term><literal>EXCLUDE_SRCS</literal></term>
2725 <indexterm><primary><literal>EXCLUDE_SRCS</literal></primary>
2728 <para>Set to a list of source files (relative to the
2729 current directory) to omit from the automatic
2730 search. The source searching machinery is clever
2731 enough to know that if you exclude a source file
2732 from which other sources are derived, then the
2733 derived sources should also be excluded. For
2734 example, if you set <literal>EXCLUDED_SRCS</literal>
2735 to include <filename>Foo.y</filename>, then
2736 <filename>Foo.hs</filename> will also be
2742 <term><literal>EXTRA_SRCS</literal></term>
2743 <indexterm><primary><literal>EXCLUDE_SRCS</literal></primary>
2746 <para>Set to a list of extra source files (perhaps
2747 in directories not listed in
2748 <literal>ALL_DIRS</literal>) that should be
2754 <para>The results of the automatic source file search are
2755 placed in the following make variables:</para>
2759 <term><literal>SRCS</literal></term>
2760 <indexterm><primary><literal>SRCS</literal></primary></indexterm>
2762 <para>All source files found, sorted and without
2763 duplicates, including those which might not exist
2764 yet but will be derived from other existing sources.
2765 <literal>SRCS</literal> <emphasis>can</emphasis> be
2766 overriden if necessary, in which case the variables
2767 below will follow suit.</para>
2772 <term><literal>HS_SRCS</literal></term>
2773 <indexterm><primary><literal>HS_SRCS</literal></primary></indexterm>
2775 <para>all Haskell source files in the current
2776 directory, including those derived from other source
2777 files (eg. Happy sources also give rise to Haskell
2783 <term><literal>HS_OBJS</literal></term>
2784 <indexterm><primary><literal>HS_OBJS</literal></primary></indexterm>
2786 <para>Object files derived from
2787 <literal>HS_SRCS</literal>.</para>
2792 <term><literal>HS_IFACES</literal></term>
2793 <indexterm><primary><literal>HS_IFACES</literal></primary></indexterm>
2795 <para>Interface files (<literal>.hi</literal> files)
2796 derived from <literal>HS_SRCS</literal>.</para>
2801 <term><literal>C_SRCS</literal></term>
2802 <indexterm><primary><literal>C_SRCS</literal></primary></indexterm>
2804 <para>All C source files found.</para>
2809 <term><literal>C_OBJS</literal></term>
2810 <indexterm><primary><literal>C_OBJS</literal></primary></indexterm>
2812 <para>Object files derived from
2813 <literal>C_SRCS</literal>.</para>
2818 <term><literal>SCRIPT_SRCS</literal></term>
2819 <indexterm><primary><literal>SCRIPT_SRCS</literal></primary></indexterm>
2821 <para>All script source files found
2822 (<literal>.lprl</literal> files).</para>
2827 <term><literal>SCRIPT_OBJS</literal></term>
2828 <indexterm><primary><literal>SCRIPT_OBJS</literal></primary></indexterm>
2830 <para><quote>object</quote> files derived from
2831 <literal>SCRIPT_SRCS</literal>
2832 (<literal>.prl</literal> files).</para>
2837 <term><literal>HSC_SRCS</literal></term>
2838 <indexterm><primary><literal>HSC_SRCS</literal></primary></indexterm>
2840 <para>All <literal>hsc2hs</literal> source files
2841 (<literal>.hsc</literal> files).</para>
2846 <term><literal>HAPPY_SRCS</literal></term>
2847 <indexterm><primary><literal>HAPPY_SRCS</literal></primary></indexterm>
2849 <para>All <literal>happy</literal> source files
2850 (<literal>.y</literal> or <literal>.hy</literal> files).</para>
2855 <term><literal>OBJS</literal></term>
2856 <indexterm><primary>OBJS</primary></indexterm>
2858 <para>the concatenation of
2859 <literal>$(HS_OBJS)</literal>,
2860 <literal>$(C_OBJS)</literal>, and
2861 <literal>$(SCRIPT_OBJS)</literal>.</para>
2866 <para>Any or all of these definitions can easily be
2867 overriden by giving new definitions in your
2868 <filename>Makefile</filename>.</para>
2870 <para>What, exactly, does <filename>paths.mk</filename>
2871 consider a <quote>source file</quote> to be? It's based
2872 on the file's suffix (e.g. <filename>.hs</filename>,
2873 <filename>.lhs</filename>, <filename>.c</filename>,
2874 <filename>.hy</filename>, etc), but this is the kind of
2875 detail that changes, so rather than enumerate the source
2876 suffices here the best thing to do is to look in
2877 <filename>paths.mk</filename>.</para>
2882 <term><filename>opts.mk</filename></term>
2883 <indexterm><primary>opts.mk</primary></indexterm>
2885 <para>defines <command>make</command> variables for option
2886 strings to pass to each program. For example, it defines
2887 <constant>HC_OPTS</constant><indexterm><primary>HC_OPTS</primary></indexterm>,
2888 the option strings to pass to the Haskell compiler. See
2889 <Xref LinkEnd="sec-suffix">.</para>
2894 <term><filename>suffix.mk</filename></term>
2895 <indexterm><primary>suffix.mk</primary></indexterm>
2897 <para>defines standard pattern rules—see <Xref
2898 LinkEnd="sec-suffix">.</para>
2903 <para>Any of the variables and pattern rules defined by the
2904 boilerplate file can easily be overridden in any particular
2905 <filename>Makefile</filename>, because the boilerplate
2906 <literal>include</literal> comes first. Definitions after this
2907 <literal>include</literal> directive simply override the default
2908 ones in <filename>boilerplate.mk</filename>.</para>
2911 <sect2 id="sec-suffix">
2912 <title>Pattern rules and options</title>
2913 <indexterm><primary>Pattern rules</primary></indexterm>
2916 <filename>suffix.mk</filename><indexterm><primary>suffix.mk</primary></indexterm>
2917 defines standard <emphasis>pattern rules</emphasis> that say how
2918 to build one kind of file from another, for example, how to
2919 build a <filename>.o</filename> file from a
2920 <filename>.c</filename> file. (GNU <command>make</command>'s
2921 <emphasis>pattern rules</emphasis> are more powerful and easier
2922 to use than Unix <command>make</command>'s <emphasis>suffix
2923 rules</emphasis>.)</para>
2925 <para>Almost all the rules look something like this:</para>
2930 $(CC) $(CC_OPTS) -c $< -o $@
2933 <para>Here's how to understand the rule. It says that
2934 <emphasis>something</emphasis><filename>.o</filename> (say
2935 <filename>Foo.o</filename>) can be built from
2936 <emphasis>something</emphasis><filename>.c</filename>
2937 (<filename>Foo.c</filename>), by invoking the C compiler (path
2938 name held in <constant>$(CC)</constant>), passing to it
2939 the options <constant>$(CC_OPTS)</constant> and
2940 the rule's dependent file of the rule
2941 <literal>$<</literal> (<filename>Foo.c</filename> in
2942 this case), and putting the result in the rule's target
2943 <literal>$@</literal> (<filename>Foo.o</filename> in this
2946 <para>Every program is held in a <command>make</command>
2947 variable defined in <filename>mk/config.mk</filename>—look
2948 in <filename>mk/config.mk</filename> for the complete list. One
2949 important one is the Haskell compiler, which is called
2950 <constant>$(HC)</constant>.</para>
2952 <para>Every program's options are are held in a
2953 <command>make</command> variables called
2954 <constant><prog>_OPTS</constant>. the
2955 <constant><prog>_OPTS</constant> variables are
2956 defined in <filename>mk/opts.mk</filename>. Almost all of them
2957 are defined like this:</para>
2960 CC_OPTS = $(SRC_CC_OPTS) $(WAY$(_way)_CC_OPTS) $($*_CC_OPTS) $(EXTRA_CC_OPTS)
2963 <para>The four variables from which
2964 <constant>CC_OPTS</constant> is built have the following
2969 <term><constant>SRC_CC_OPTS</constant><indexterm><primary>SRC_CC_OPTS</primary></indexterm>:</term>
2971 <para>options passed to all C compilations.</para>
2976 <term><constant>WAY_<way>_CC_OPTS</constant>:</term>
2978 <para>options passed to C compilations for way
2979 <literal><way></literal>. For example,
2980 <constant>WAY_mp_CC_OPTS</constant>
2981 gives options to pass to the C compiler when compiling way
2982 <literal>mp</literal>. The variable
2983 <constant>WAY_CC_OPTS</constant> holds
2984 options to pass to the C compiler when compiling the
2985 standard way. (<Xref LinkEnd="sec-ways"> dicusses
2986 multi-way compilation.)</para>
2991 <term><constant><module>_CC_OPTS</constant>:</term>
2993 <para>options to pass to the C compiler that are specific
2994 to module <literal><module></literal>. For example,
2995 <constant>SMap_CC_OPTS</constant> gives the
2996 specific options to pass to the C compiler when compiling
2997 <filename>SMap.c</filename>.</para>
3002 <term><constant>EXTRA_CC_OPTS</constant><indexterm><primary>EXTRA_CC_OPTS</primary></indexterm>:</term>
3004 <para>extra options to pass to all C compilations. This
3005 is intended for command line use, thus:</para>
3008 gmake libHS.a EXTRA_CC_OPTS="-v"
3015 <sect2 id="sec-targets">
3016 <title>The main <filename>mk/target.mk</filename> file</title>
3017 <indexterm><primary>target.mk</primary></indexterm>
3019 <para><filename>target.mk</filename> contains canned rules for
3020 all the standard targets described in <Xref
3021 LinkEnd="sec-standard-targets">. It is complicated by the fact
3022 that you don't want all of these rules to be active in every
3023 <filename>Makefile</filename>. Rather than have a plethora of
3024 tiny files which you can include selectively, there is a single
3025 file, <filename>target.mk</filename>, which selectively includes
3026 rules based on whether you have defined certain variables in
3027 your <filename>Makefile</filename>. This section explains what
3028 rules you get, what variables control them, and what the rules
3029 do. Hopefully, you will also get enough of an idea of what is
3030 supposed to happen that you can read and understand any weird
3031 special cases yourself.</para>
3035 <term><constant>HS_PROG</constant><indexterm><primary>HS_PROG</primary></indexterm>.</term>
3037 <para>If <constant>HS_PROG</constant> is defined,
3038 you get rules with the following targets:</para>
3042 <term><filename>HS_PROG</filename><indexterm><primary>HS_PROG</primary></indexterm></term>
3044 <para>itself. This rule links
3045 <constant>$(OBJS)</constant> with the Haskell
3046 runtime system to get an executable called
3047 <constant>$(HS_PROG)</constant>.</para>
3052 <term><literal>install</literal><indexterm><primary>install</primary></indexterm></term>
3055 <constant>$(HS_PROG)</constant> in
3056 <constant>$(bindir)</constant>.</para>
3065 <term><constant>C_PROG</constant><indexterm><primary>C_PROG</primary></indexterm></term>
3067 <para>is similar to <constant>HS_PROG</constant>,
3068 except that the link step links
3069 <constant>$(C_OBJS)</constant> with the C
3070 runtime system.</para>
3075 <term><constant>LIBRARY</constant><indexterm><primary>LIBRARY</primary></indexterm></term>
3077 <para>is similar to <constant>HS_PROG</constant>,
3078 except that it links
3079 <constant>$(LIB_OBJS)</constant> to make the
3080 library archive <constant>$(LIBRARY)</constant>,
3081 and <literal>install</literal> installs it in
3082 <constant>$(libdir)</constant>.</para>
3087 <term><constant>LIB_DATA</constant><indexterm><primary>LIB_DATA</primary></indexterm></term>
3089 <para>…</para>
3094 <term><constant>LIB_EXEC</constant><indexterm><primary>LIB_EXEC</primary></indexterm></term>
3096 <para>…</para>
3101 <term><constant>HS_SRCS</constant><indexterm><primary>HS_SRCS</primary></indexterm>, <constant>C_SRCS</constant><indexterm><primary>C_SRCS</primary></indexterm>.</term>
3103 <para>If <constant>HS_SRCS</constant> is defined
3104 and non-empty, a rule for the target
3105 <literal>depend</literal> is included, which generates
3106 dependency information for Haskell programs. Similarly
3107 for <constant>C_SRCS</constant>.</para>
3112 <para>All of these rules are “double-colon” rules,
3116 install :: $(HS_PROG)
3117 ...how to install it...
3120 <para>GNU <command>make</command> treats double-colon rules as
3121 separate entities. If there are several double-colon rules for
3122 the same target it takes each in turn and fires it if its
3123 dependencies say to do so. This means that you can, for
3124 example, define both <constant>HS_PROG</constant> and
3125 <constant>LIBRARY</constant>, which will generate two rules for
3126 <literal>install</literal>. When you type <command>gmake
3127 install</command> both rules will be fired, and both the program
3128 and the library will be installed, just as you wanted.</para>
3131 <sect2 id="sec-subdirs">
3132 <title>Recursion</title>
3133 <indexterm><primary>recursion, in makefiles</primary></indexterm>
3134 <indexterm><primary>Makefile, recursing into subdirectories</primary></indexterm>
3136 <para>In leaf <filename>Makefile</filename>s the variable
3137 <constant>SUBDIRS</constant><indexterm><primary>SUBDIRS</primary></indexterm>
3138 is undefined. In non-leaf <filename>Makefile</filename>s,
3139 <constant>SUBDIRS</constant> is set to the list of
3140 sub-directories that contain subordinate
3141 <filename>Makefile</filename>s. <emphasis>It is up to you to
3142 set <constant>SUBDIRS</constant> in the
3143 <filename>Makefile</filename>.</emphasis> There is no automation
3144 here—<constant>SUBDIRS</constant> is too important to
3147 <para>When <constant>SUBDIRS</constant> is defined,
3148 <filename>target.mk</filename> includes a rather neat rule for
3149 the standard targets (<Xref LinkEnd="sec-standard-targets"> that
3150 simply invokes <command>make</command> recursively in each of
3151 the sub-directories.</para>
3153 <para><emphasis>These recursive invocations are guaranteed to
3154 occur in the order in which the list of directories is specified
3155 in <constant>SUBDIRS</constant>. </emphasis>This guarantee can
3156 be important. For example, when you say <command>gmake
3157 boot</command> it can be important that the recursive invocation
3158 of <command>make boot</command> is done in one sub-directory
3159 (the include files, say) before another (the source files).
3160 Generally, put the most independent sub-directory first, and the
3161 most dependent last.</para>
3164 <sect2 id="sec-ways">
3165 <title>Way management</title>
3166 <indexterm><primary>way management</primary></indexterm>
3168 <para>We sometimes want to build essentially the same system in
3169 several different “ways”. For example, we want to build GHC's
3170 <literal>Prelude</literal> libraries with and without profiling,
3171 so that there is an appropriately-built library archive to link
3172 with when the user compiles his program. It would be possible
3173 to have a completely separate build tree for each such “way”,
3174 but it would be horribly bureaucratic, especially since often
3175 only parts of the build tree need to be constructed in multiple
3179 <filename>target.mk</filename><indexterm><primary>target.mk</primary></indexterm>
3180 contains some clever magic to allow you to build several
3181 versions of a system; and to control locally how many versions
3182 are built and how they differ. This section explains the
3185 <para>The files for a particular way are distinguished by
3186 munging the suffix. The <quote>normal way</quote> is always
3187 built, and its files have the standard suffices
3188 <filename>.o</filename>, <filename>.hi</filename>, and so on.
3189 In addition, you can build one or more extra ways, each
3190 distinguished by a <emphasis>way tag</emphasis>. The object
3191 files and interface files for one of these extra ways are
3192 distinguished by their suffix. For example, way
3193 <literal>mp</literal> has files
3194 <filename>.mp_o</filename> and
3195 <filename>.mp_hi</filename>. Library archives have their
3196 way tag the other side of the dot, for boring reasons; thus,
3197 <filename>libHS_mp.a</filename>.</para>
3199 <para>A <command>make</command> variable called
3200 <constant>way</constant> holds the current way tag.
3201 <emphasis><constant>way</constant> is only ever set on the
3202 command line of <command>gmake</command></emphasis> (usually in
3203 a recursive invocation of <command>gmake</command> by the
3204 system). It is never set inside a
3205 <filename>Makefile</filename>. So it is a global constant for
3206 any one invocation of <command>gmake</command>. Two other
3207 <command>make</command> variables,
3208 <constant>way_</constant> and
3209 <constant>_way</constant> are immediately derived from
3210 <constant>$(way)</constant> and never altered. If
3211 <constant>way</constant> is not set, then neither are
3212 <constant>way_</constant> and
3213 <constant>_way</constant>, and the invocation of
3214 <command>make</command> will build the <quote>normal
3215 way</quote>. If <constant>way</constant> is set, then the other
3216 two variables are set in sympathy. For example, if
3217 <constant>$(way)</constant> is “<literal>mp</literal>”,
3218 then <constant>way_</constant> is set to
3219 “<literal>mp_</literal>” and
3220 <constant>_way</constant> is set to
3221 “<literal>_mp</literal>”. These three variables are
3222 then used when constructing file names.</para>
3224 <para>So how does <command>make</command> ever get recursively
3225 invoked with <constant>way</constant> set? There are two ways
3226 in which this happens:</para>
3230 <para>For some (but not all) of the standard targets, when
3231 in a leaf sub-directory, <command>make</command> is
3232 recursively invoked for each way tag in
3233 <constant>$(WAYS)</constant>. You set
3234 <constant>WAYS</constant> in the
3235 <filename>Makefile</filename> to the list of way tags you
3236 want these targets built for. The mechanism here is very
3237 much like the recursive invocation of
3238 <command>make</command> in sub-directories (<Xref
3239 LinkEnd="sec-subdirs">). It is up to you to set
3240 <constant>WAYS</constant> in your
3241 <filename>Makefile</filename>; this is how you control what
3242 ways will get built.</para>
3246 <para>For a useful collection of targets (such as
3247 <filename>libHS_mp.a</filename>,
3248 <filename>Foo.mp_o</filename>) there is a rule which
3249 recursively invokes <command>make</command> to make the
3250 specified target, setting the <constant>way</constant>
3251 variable. So if you say <command>gmake
3252 Foo.mp_o</command> you should see a recursive
3253 invocation <command>gmake Foo.mp_o way=mp</command>,
3254 and <emphasis>in this recursive invocation the pattern rule
3255 for compiling a Haskell file into a <filename>.o</filename>
3256 file will match</emphasis>. The key pattern rules (in
3257 <filename>suffix.mk</filename>) look like this:
3261 $(HC) $(HC_OPTS) $< -o $@
3268 <para>You can invoke <command>make</command> with a
3269 particular <literal>way</literal> setting yourself, in order
3270 to build files related to a particular
3271 <literal>way</literal> in the current directory. eg.
3277 will build files for the profiling way only in the current
3284 <title>When the canned rule isn't right</title>
3286 <para>Sometimes the canned rule just doesn't do the right thing.
3287 For example, in the <literal>nofib</literal> suite we want the
3288 link step to print out timing information. The thing to do here
3289 is <emphasis>not</emphasis> to define
3290 <constant>HS_PROG</constant> or
3291 <constant>C_PROG</constant>, and instead define a special
3292 purpose rule in your own <filename>Makefile</filename>. By
3293 using different variable names you will avoid the canned rules
3294 being included, and conflicting with yours.</para>
3298 <sect1 id="building-docs">
3299 <title>Building the documentation</title>
3301 <sect2 id="pre-supposed-doc-tools">
3302 <title>Tools for building the Documentation</title>
3304 <para>The following additional tools are required if you want to
3305 format the documentation that comes with the
3306 <literal>fptools</literal> projects:</para>
3310 <term>DocBook</term>
3311 <indexterm><primary>pre-supposed: DocBook</primary></indexterm>
3312 <indexterm><primary>DocBook, pre-supposed</primary></indexterm>
3314 <para>Much of our documentation is written in SGML, using
3315 the DocBook DTD. Instructions on installing and
3316 configuring the DocBook tools are below.</para>
3322 <indexterm><primary>pre-supposed: TeX</primary></indexterm>
3323 <indexterm><primary>TeX, pre-supposed</primary></indexterm>
3325 <para>A decent TeX distribution is required if you want to
3326 produce printable documentation. We recomment teTeX,
3327 which includes just about everything you need.</para>
3332 <term>Haddock</term>
3333 <indexterm><primary>Haddock</primary>
3336 <para>Haddock is a Haskell documentation tool that we use
3337 for automatically generating documentation from the
3338 library source code. It is an <literal>fptools</literal>
3339 project in itself. To build documentation for the
3340 libraries (<literal>fptools/libraries</literal>) you
3341 should check out and build Haddock in
3342 <literal>fptools/haddock</literal>. Haddock requires GHC
3350 <title>Installing the DocBook tools</title>
3353 <title>Installing the DocBook tools on Linux</title>
3355 <para>If you're on a recent RedHat system (7.0+), you probably
3356 have working DocBook tools already installed. The configure
3357 script should detect your setup and you're away.</para>
3359 <para>If you don't have DocBook tools installed, and you are
3360 using a system that can handle RedHat RPM packages, you can
3361 probably use the <ULink
3362 URL="http://sourceware.cygnus.com/docbook-tools/">Cygnus
3363 DocBook tools</ULink>, which is the most shrink-wrapped SGML
3364 suite that we could find. You need all the RPMs except for
3365 psgml (i.e. <Filename>docbook</Filename>,
3366 <Filename>jade</Filename>, <Filename>jadetex</Filename>,
3367 <Filename>sgmlcommon</Filename> and
3368 <Filename>stylesheets</Filename>). Note that most of these
3369 RPMs are architecture neutral, so are likely to be found in a
3370 <Filename>noarch</Filename> directory. The SuSE RPMs also
3371 work; the RedHat ones <Emphasis>don't</Emphasis> in RedHat 6.2
3372 (7.0 and later should be OK), but they are easy to fix: just
3374 <Filename>/usr/lib/sgml/stylesheets/nwalsh-modular/lib/dblib.dsl</Filename>
3375 to <Filename>/usr/lib/sgml/lib/dblib.dsl</Filename>. </para>
3379 <title>Installing DocBook on FreeBSD</title>
3381 <para>On FreeBSD systems, the easiest way to get DocBook up
3382 and running is to install it from the ports tree or a
3383 pre-compiled package (packages are available from your local
3384 FreeBSD mirror site).</para>
3386 <para>To use the ports tree, do this:
3388 $ cd /usr/ports/textproc/docproj
3391 This installs the FreeBSD documentation project tools, which
3392 includes everything needed to format the GHC
3393 documentation.</para>
3397 <title>Installing from binaries on Windows</title>
3399 <Para>It's a good idea to use Norman Walsh's <ULink
3400 URL="http://nwalsh.com/docbook/dsssl/doc/install.html">installation
3401 notes</ULink> as a guide. You should get version 3.1 of
3402 DocBook, and note that his file <Filename>test.sgm</Filename>
3403 won't work, as it needs version 3.0. You should unpack Jade
3404 into <Filename>\Jade</Filename>, along with the entities,
3405 DocBook into <Filename>\docbook</Filename>, and the DocBook
3406 stylesheets into <Filename>\docbook\stylesheets</Filename> (so
3407 they actually end up in
3408 <Filename>\docbook\stylesheets\docbook</Filename>).</para>
3413 <title>Installing the DocBook tools from source</title>
3418 <para>Install <ULink
3419 URL="http://openjade.sourceforge.net/">OpenJade</ULink>
3420 (Windows binaries are available as well as sources). If you
3421 want DVI, PS, or PDF then install JadeTeX from the
3422 <Filename>dsssl</Filename> subdirectory. (If you get the
3426 ! LaTeX Error: Unknown option implicit=false' for package hyperref'.
3429 your version of <Command>hyperref</Command> is out of date;
3430 download it from CTAN
3431 (<Filename>macros/latex/contrib/supported/hyperref</Filename>),
3432 and make it, ensuring that you have first removed or renamed
3433 your old copy. If you start getting file not found errors
3434 when making the test for <Command>hyperref</Command>, you
3435 can abort at that point and proceed straight to
3436 <Command>make install</Command>, or enter them as
3437 <Filename>../</Filename><Emphasis>filename</Emphasis>.)</para>
3439 <para>Make links from <Filename>virtex</Filename> to
3440 <Filename>jadetex</Filename> and
3441 <Filename>pdfvirtex</Filename> to
3442 <Filename>pdfjadetex</Filename> (otherwise DVI, PostScript
3443 and PDF output will not work). Copy
3444 <Filename>dsssl/*.{dtd,dsl}</Filename> and
3445 <Filename>catalog</Filename> to
3446 <Filename>/usr/[local/]lib/sgml</Filename>.</para>
3450 <title>DocBook and the DocBook stylesheets</title>
3452 <para>Get a Zip of <ULink
3453 URL="http://www.oasis-open.org/docbook/sgml/3.1/index.html">DocBook</ULink>
3454 and install the contents in
3455 <Filename>/usr/[local/]/lib/sgml</Filename>.</para>
3457 <para>Get the <ULink
3458 URL="http://nwalsh.com/docbook/dsssl/">DocBook
3459 stylesheets</ULink> and install in
3460 <Filename>/usr/[local/]lib/sgml/stylesheets</Filename>
3461 (thereby creating a subdirectory docbook). For indexing,
3462 copy or link <Filename>collateindex.pl</Filename> from the
3463 DocBook stylesheets archive in <Filename>bin</Filename> into
3464 a directory on your <Constant>PATH</Constant>.</para>
3466 <para>Download the <ULink
3467 URL="http://www.oasis-open.org/cover/ISOEnts.zip">ISO
3468 entities</ULink> into
3469 <Filename>/usr/[local/]lib/sgml</Filename>.</para>
3475 <title>Configuring the DocBook tools</title>
3477 <Para>Once the DocBook tools are installed, the configure script
3478 will detect them and set up the build system accordingly. If you
3479 have a system that isn't supported, let us know, and we'll try
3484 <title>Remaining problems</title>
3486 <para>If you install from source, you'll get a pile of warnings
3489 <Screen>DTDDECL catalog entries are not supported</Screen>
3491 every time you build anything. These can safely be ignored, but
3492 if you find them tedious you can get rid of them by removing all
3493 the <Constant>DTDDECL</Constant> entries from
3494 <Filename>docbook.cat</Filename>.</para>
3498 <title>Building the documentation</title>
3500 <para>To build documentation in a certain format, you can
3501 say, for example,</para>
3507 <para>to build HTML documentation below the current directory.
3508 The available formats are: <literal>dvi</literal>,
3509 <literal>ps</literal>, <literal>pdf</literal>,
3510 <literal>html</literal>, and <literal>rtf</literal>. Note that
3511 not all documentation can be built in all of these formats: HTML
3512 documentation is generally supported everywhere, and DocBook
3513 documentation might support the other formats (depending on what
3514 other tools you have installed).</para>
3516 <para>All of these targets are recursive; that is, saying
3517 <literal>make html</literal> will make HTML docs for all the
3518 documents recursively below the current directory.</para>
3520 <para>Because there are many different formats that the DocBook
3521 documentation can be generated in, you have to select which ones
3522 you want by setting the <literal>SGMLDocWays</literal> variable
3523 to a list of them. For example, in
3524 <filename>build.mk</filename> you might have a line:</para>
3527 SGMLDocWays = html ps
3530 <para>This will cause the documentation to be built in the requested
3531 formats as part of the main build (the default is not to build
3532 any documentation at all).</para>
3536 <title>Installing the documentation</title>
3538 <para>To install the documentation, use:</para>
3544 <para>This will install the documentation into
3545 <literal>$(datadir)</literal> (which defaults to
3546 <literal>$(prefix)/share</literal>). The exception is HTML
3547 documentation, which goes into
3548 <literal>$(datadir)/html</literal>, to keep things tidy.</para>
3550 <para>Note that unless you set <literal>$(SGMLDocWays)</literal>
3551 to a list of formats, the <literal>install-docs</literal> target
3552 won't do anything for SGML documentation.</para>
3558 <sect1 id="sec-porting-ghc">
3559 <title>Porting GHC</title>
3561 <para>This section describes how to port GHC to a currenly
3562 unsupported platform. There are two distinct
3563 possibilities:</para>
3567 <para>The hardware architecture for your system is already
3568 supported by GHC, but you're running an OS that isn't
3569 supported (or perhaps has been supported in the past, but
3570 currently isn't). This is the easiest type of porting job,
3571 but it still requires some careful bootstrapping. Proceed to
3572 <xref linkend="sec-booting-from-hc">.</para>
3576 <para>Your system's hardware architecture isn't supported by
3577 GHC. This will be a more difficult port (though by comparison
3578 perhaps not as difficult as porting gcc). Proceed to <xref
3579 linkend="unregisterised-porting">.</para>
3583 <sect2 id="sec-booting-from-hc">
3584 <title>Booting/porting from C (<filename>.hc</filename>) files</title>
3586 <indexterm><primary>building GHC from .hc files</primary></indexterm>
3587 <indexterm><primary>booting GHC from .hc files</primary></indexterm>
3588 <indexterm><primary>porting GHC</primary></indexterm>
3590 <para>Bootstrapping GHC on a system without GHC already
3591 installed is achieved by taking the intermediate C files (known
3592 as HC files) from a GHC compilation on a supported system to the
3593 target machine, and compiling them using gcc to get a working
3596 <para><emphasis>NOTE: GHC version 5.xx is significantly harder
3597 to bootstrap from C than previous versions. We recommend
3598 starting from version 4.08.2 if you need to bootstrap in this
3599 way.</emphasis></para>
3601 <para>HC files are architecture-dependent (but not
3602 OS-dependent), so you have to get a set that were generated on
3603 similar hardware. There may be some supplied on the GHC
3604 download page, otherwise you'll have to compile some up
3605 yourself, or start from <emphasis>unregisterised</emphasis> HC
3606 files - see <xref linkend="unregisterised-porting">.</para>
3608 <para>The following steps should result in a working GHC build
3609 with full libraries:</para>
3613 <para>Unpack the HC files on top of a fresh source tree
3614 (make sure the source tree version matches the version of
3615 the HC files <emphasis>exactly</emphasis>!). This will
3616 place matching <filename>.hc</filename> files next to the
3617 corresponding Haskell source (<filename>.hs</filename> or
3618 <filename>.lhs</filename>) in the compiler subdirectory
3619 <filename>ghc/compiler</filename> and in the libraries
3620 (subdirectories of <filename>hslibs</filename> and
3621 <literal>libraries</literal>).</para>
3625 <para>The actual build process is fully automated by the
3626 <filename>hc-build</filename> script located in the
3627 <filename>distrib</filename> directory. If you eventually
3628 want to install GHC into the directory
3629 <replaceable>dir</replaceable>, the following
3630 command will execute the whole build process (it won't
3631 install yet):</para>
3634 foo% distrib/hc-build --prefix=<replaceable>dir</replaceable>
3636 <indexterm><primary>--hc-build</primary></indexterm>
3638 <para>By default, the installation directory is
3639 <filename>/usr/local</filename>. If that is what you want,
3640 you may omit the argument to <filename>hc-build</filename>.
3641 Generally, any option given to <filename>hc-build</filename>
3642 is passed through to the configuration script
3643 <filename>configure</filename>. If
3644 <filename>hc-build</filename> successfully completes the
3645 build process, you can install the resulting system, as
3655 <sect2 id="unregisterised-porting">
3656 <title>Porting GHC to a new architecture</title>
3658 <para>The first step in porting to a new architecture is to get
3659 an <firstterm>unregisterised</firstterm> build working. An
3660 unregisterised build is one that compiles via vanilla C only.
3661 By contrast, a registerised build uses the following
3662 architecture-specific hacks for speed:</para>
3666 <para>Global register variables: certain abstract machine
3667 <quote>registers</quote> are mapped to real machine
3668 registers, depending on how many machine registers are
3670 <filename>ghc/includes/MachRegs.h</filename>).</para>
3674 <para>Assembly-mangling: when compiling via C, we feed the
3675 assembly generated by gcc though a Perl script known as the
3676 <firstterm>mangler</firstterm> (see
3677 <filename>ghc/driver/mangler/ghc-asm.lprl</filename>). The
3678 mangler rearranges the assembly to support tail-calls and
3679 various other optimisations.</para>
3683 <para>In an unregisterised build, neither of these hacks are
3684 used — the idea is that the C code generated by the
3685 compiler should compile using gcc only. The lack of these
3686 optimisations costs about a factor of two in performance, but
3687 since unregisterised compilation is usually just a step on the
3688 way to a full registerised port, we don't mind too much.</para>
3691 <title>Building an unregisterised port</title>
3693 <para>The first step is to get some unregisterised HC files.
3694 Either (a) download them from the GHC site (if there are
3695 some available for the right version of GHC), or
3696 (b) build them yourself on any machine with a working
3697 GHC. If at all possible this should be a machine with the
3698 same word size as the target.</para>
3700 <para>There is a script available which should automate the
3701 process of doing the 2-stage bootstrap necessary to get the
3702 unregisterised HC files - it's available in <ulink
3703 url="http://cvs.haskell.org/cgi-bin/cvsweb.cgi/fptools/distrib/cross-port"><filename>fptools/distrib/cross-port</filename></ulink>
3706 <para>Now take these unregisterised HC files to the target
3707 platform and bootstrap a compiler from them as per the
3708 instructions in <xref linkend="sec-booting-from-hc">. In
3709 <filename>build.mk</filename>, you need to tell the build
3710 system that the compiler you're building is
3711 (a) unregisterised itself, and (b) builds
3712 unregisterised binaries. This varies depending on the GHC
3713 version you're bootstraping:</para>
3716 # build.mk for GHC 4.08.x
3717 GhcWithRegisterised=NO
3721 # build.mk for GHC 5.xx
3722 GhcUnregisterised=YES
3725 <para>Version 5.xx only: use the option
3726 <option>--enable-hc-boot-unregisterised</option> instead of
3727 <option>--enable-hc-boot</option> when running
3728 <filename>./configure</filename>.</para>
3730 <para>The build may not go through cleanly. We've tried to
3731 stick to writing portable code in most parts of the compiler,
3732 so it should compile on any POSIXish system with gcc, but in
3733 our experience most systems differ from the standards in one
3734 way or another. Deal with any problems as they arise - if you
3735 get stuck, ask the experts on
3736 <email>glasgow-haskell-users@haskell.org</email>.</para>
3738 <para>Once you have the unregisterised compiler up and
3739 running, you can use it to start a registerised port. The
3740 following sections describe the various parts of the system
3741 that will need architecture-specific tweaks in order to get a
3742 registerised build going.</para>
3744 <para>Lots of useful information about the innards of GHC is
3745 available in the <ulink
3746 url="http://www.cse.unsw.edu.au/~chak/haskell/ghc/comm/">GHC
3747 Commentary</ulink>, which might be helpful if you run into
3748 some code which needs tweaking for your system.</para>
3752 <title>Porting the RTS</title>
3754 <para>The following files need architecture-specific code for a
3755 registerised build:</para>
3759 <term><filename>ghc/includes/MachRegs.h</filename></term>
3760 <indexterm><primary><filename>MachRegs.h</filename></primary>
3763 <para>Defines the STG-register to machine-register
3764 mapping. You need to know your platform's C calling
3765 convention, and which registers are generally available
3766 for mapping to global register variables. There are
3767 plenty of useful comments in this file.</para>
3771 <term><filename>ghc/includes/TailCalls.h</filename></term>
3772 <indexterm><primary><filename>TailCalls.h</filename></primary>
3775 <para>Macros that cooperate with the mangler (see <xref
3776 linkend="sec-mangler">) to make proper tail-calls
3781 <term><filename>ghc/rts/Adjustor.c</filename></term>
3782 <indexterm><primary><filename>Adjustor.c</filename></primary>
3786 <literal>foreign import "wrapper"</literal>
3788 <literal>foreign export dynamic</literal>).
3789 Not essential for getting GHC bootstrapped, so this file
3790 can be deferred until later if necessary.</para>
3794 <term><filename>ghc/rts/StgCRun.c</filename></term>
3795 <indexterm><primary><filename>StgCRun.c</filename></primary>
3798 <para>The little assembly layer between the C world and
3799 the Haskell world. See the comments and code for the
3800 other architectures in this file for pointers.</para>
3804 <term><filename>ghc/rts/MBlock.h</filename></term>
3805 <term><filename>ghc/rts/MBlock.c</filename></term>
3806 <indexterm><primary><filename>MBlock.h</filename></primary>
3808 <indexterm><primary><filename>MBlock.c</filename></primary>
3811 <para>These files are really OS-specific rather than
3812 architecture-specific. In <filename>MBlock.h</filename>
3813 is specified the absolute location at which the RTS
3814 should try to allocate memory on your platform (try to
3815 find an area which doesn't conflict with code or dynamic
3816 libraries). In <filename>Mblock.c</filename> you might
3817 need to tweak the call to <literal>mmap()</literal> for
3824 <sect3 id="sec-mangler">
3825 <title>The mangler</title>
3827 <para>The mangler is an evil Perl-script that rearranges the
3828 assembly code output from gcc to do two main things:</para>
3832 <para>Remove function prologues and epilogues, and all
3833 movement of the C stack pointer. This is to support
3834 tail-calls: every code block in Haskell code ends in an
3835 explicit jump, so we don't want the C-stack overflowing
3836 while we're jumping around between code blocks.</para>
3839 <para>Move the <firstterm>info table</firstterm> for a
3840 closure next to the entry code for that closure. In
3841 unregisterised code, info tables contain a pointer to the
3842 entry code, but in registerised compilation we arrange
3843 that the info table is shoved right up against the entry
3844 code, and addressed backwards from the entry code pointer
3845 (this saves a word in the info table and an extra
3846 indirection when jumping to the closure entry
3851 <para>The mangler is abstracted to a certain extent over some
3852 architecture-specific things such as the particular assembler
3853 directives used to herald symbols. Take a look at the
3854 definitions for other architectures and use these as a
3855 starting point.</para>
3859 <title>The native code generator</title>
3861 <para>The native code generator isn't essential to getting a
3862 registerised build going, but it's a desirable thing to have
3863 because it can cut compilation times in half. The native code
3864 generator is described in some detail in the <ulink
3865 url="http://www.cse.unsw.edu.au/~chak/haskell/ghc/comm/">GHC
3866 commentary</ulink>.</para>
3872 <para>To support GHCi, you need to port the dynamic linker
3873 (<filename>fptools/ghc/rts/Linker.c</filename>). The linker
3874 currently supports the ELF and PEi386 object file formats - if
3875 your platform uses one of these then you probably don't have
3876 to do anything except fiddle with the
3877 <literal>#ifdef</literal>s at the top of
3878 <filename>Linker.c</filename> to tell it about your OS.</para>
3880 <para>If your system uses a different object file format, then
3881 you have to write a linker — good luck!</para>
3887 <sect1 id="sec-build-pitfalls">
3888 <title>Known pitfalls in building Glasgow Haskell
3890 <indexterm><primary>problems, building</primary></indexterm>
3891 <indexterm><primary>pitfalls, in building</primary></indexterm>
3892 <indexterm><primary>building pitfalls</primary></indexterm></title>
3895 WARNINGS about pitfalls and known “problems”:
3904 One difficulty that comes up from time to time is running out of space
3905 in <literal>TMPDIR</literal>. (It is impossible for the configuration stuff to
3906 compensate for the vagaries of different sysadmin approaches to temp
3908 <indexterm><primary>tmp, running out of space in</primary></indexterm>
3910 The quickest way around it is <command>setenv TMPDIR /usr/tmp</command><indexterm><primary>TMPDIR</primary></indexterm> or
3911 even <command>setenv TMPDIR .</command> (or the equivalent incantation with your shell
3914 The best way around it is to say
3917 export TMPDIR=<dir>
3920 in your <filename>build.mk</filename> file.
3921 Then GHC and the other <literal>fptools</literal> programs will use the appropriate directory
3930 In compiling some support-code bits, e.g., in <filename>ghc/rts/gmp</filename> and even
3931 in <filename>ghc/lib</filename>, you may get a few C-compiler warnings. We think these
3939 When compiling via C, you'll sometimes get “warning: assignment from
3940 incompatible pointer type” out of GCC. Harmless.
3947 Similarly, <command>ar</command>chiving warning messages like the following are not
3951 ar: filename GlaIOMonad__1_2s.o truncated to GlaIOMonad_
3952 ar: filename GlaIOMonad__2_2s.o truncated to GlaIOMonad_
3962 In compiling the compiler proper (in <filename>compiler/</filename>), you <emphasis>may</emphasis>
3963 get an “Out of heap space” error message. These can vary with the
3964 vagaries of different systems, it seems. The solution is simple:
3971 If you're compiling with GHC 4.00 or later, then the
3972 <emphasis>maximum</emphasis> heap size must have been reached. This
3973 is somewhat unlikely, since the maximum is set to 64M by default.
3974 Anyway, you can raise it with the
3975 <option>-optCrts-M<size></option> flag (add this flag to
3976 <constant><module>_HC_OPTS</constant>
3977 <command>make</command> variable in the appropriate
3978 <filename>Makefile</filename>).
3985 For GHC < 4.00, add a suitable <option>-H</option> flag to the <filename>Makefile</filename>, as
3994 and try again: <command>gmake</command>. (see <Xref LinkEnd="sec-suffix"> for information about
3995 <constant><module>_HC_OPTS</constant>.)
3997 Alternatively, just cut to the chase:
4001 % make EXTRA_HC_OPTS=-optCrts-M128M
4010 If you try to compile some Haskell, and you get errors from GCC about
4011 lots of things from <filename>/usr/include/math.h</filename>, then your GCC was
4012 mis-installed. <command>fixincludes</command> wasn't run when it should've been.
4014 As <command>fixincludes</command> is now automagically run as part of GCC installation,
4015 this bug also suggests that you have an old GCC.
4023 You <emphasis>may</emphasis> need to re-<command>ranlib</command><indexterm><primary>ranlib</primary></indexterm> your libraries (on Sun4s).
4027 % cd $(libdir)/ghc-x.xx/sparc-sun-sunos4
4028 % foreach i ( `find . -name '*.a' -print` ) # or other-shell equiv...
4030 ? # or, on some machines: ar s $i
4035 We'd be interested to know if this is still necessary.
4043 GHC's sources go through <command>cpp</command> before being compiled, and <command>cpp</command> varies
4044 a bit from one Unix to another. One particular gotcha is macro calls
4049 SLIT("Hello, world")
4053 Some <command>cpp</command>s treat the comma inside the string as separating two macro
4054 arguments, so you get
4058 :731: macro `SLIT' used with too many (2) args
4062 Alas, <command>cpp</command> doesn't tell you the offending file!
4064 Workaround: don't put weird things in string args to <command>cpp</command> macros.
4075 <Sect1 id="winbuild"><Title>Notes for building under Windows</Title>
4078 This section summarises how to get the utilities you need on your
4079 Win95/98/NT/2000 machine to use CVS and build GHC. Similar notes for
4080 installing and running GHC may be found in the user guide. In general,
4081 Win95/Win98 behave the same, and WinNT/Win2k behave the same.
4082 You should read the GHC installation guide sections on Windows (in the user
4083 guide) before continuing to read these notes.
4087 <sect2 id="cygwin-and-mingw"><Title>Cygwin and MinGW</Title>
4089 <para> The Windows situation for building GHC is rather confusing. This section
4090 tries to clarify, and to establish terminology.</para>
4092 <sect3 id="ghc-mingw"><title>GHC-mingw</title>
4094 <para> <ulink url="http://www.mingw.org">MinGW (Minimalist GNU for Windows)</ulink>
4095 is a collection of header
4096 files and import libraries that allow one to use <command>gcc</command> and produce
4097 native Win32 programs that do not rely on any third-party DLLs. The
4098 current set of tools include GNU Compiler Collection (<command>gcc</command>), GNU Binary
4099 Utilities (Binutils), GNU debugger (Gdb), GNU make, and a assorted
4102 <para>The GHC that we distribute includes, inside the distribution itself, the MinGW <command>gcc</command>,
4103 <command>as</command>, <command>ld</command>, and a bunch of input/output libraries.
4104 GHC compiles Haskell to C (or to
4105 assembly code), and then invokes these MinGW tools to generate an executable binary.
4106 The resulting binaries can run on any Win32 system.
4108 <para> We will call a GHC that targets MinGW in this way <emphasis>GHC-mingw</emphasis>.</para>
4110 <para> The down-side of GHC-mingw is that the MinGW libraries do not support anything like the full
4111 Posix interface. So programs compiled with GHC-mingw cannot import the (Haskell) Posix
4112 library; they have to do
4113 their input output using standard Haskell I/O libraries, or native Win32 bindings.
4117 <sect3 id="ghc-cygwin"><title>GHC-cygwin</title>
4119 <para>There <emphasis>is</emphasis> a way to get the full Posix interface, which is to use Cygwin.
4120 <ulink url="http://www.cygwin.com">Cygwin</ulink> is a complete Unix simulation that runs on Win32.
4121 Cygwin comes with a shell, and all the usual Unix commands: <command>mv</command>, <command>rm</command>,
4122 <command>ls</command>, plus of course <command>gcc</command>, <command>ld</command> and so on.
4123 A C program compiled with the Cygwin <command>gcc</command> certainly can use all of Posix.
4125 <para>So why doesn't GHC use the Cygwin <command>gcc</command> and libraries? Because
4126 Cygwin comes with a DLL <emphasis>that must be linked with every runnable Cygwin-compiled program</emphasis>.
4127 A program compiled by the Cygwin tools cannot run at all unless Cygwin is installed.
4128 If GHC targeted Cygwin, users would have to install Cygwin just to run the Haskell programs
4129 that GHC compiled; and the Cygwin DLL would have to be in the DLL load path.
4130 Worse, Cygwin is a moving target. The name of the main DLL, <literal>cygwin1.dll</literal>
4131 does not change, but the implementation certainly does. Even the interfaces to functions
4132 it exports seem to change occasionally. So programs compiled by GHC might only run with
4133 particular versions of Cygwin. All of this seems very undesirable.
4136 Nevertheless, it is certainly possible to build a version of GHC that targets Cygwin;
4137 we will call that <emphasis>GHC-cygwin</emphasis>. The up-side of GHC-cygwin is
4138 that Haskell programs compiled by GHC-cygwin can import the (Haskell) Posix library.
4142 <sect3><title>HOST_OS vs TARGET_OS</title>
4145 In the source code you'll find various ifdefs looking like:
4147 #ifdef mingw32_HOST_OS
4153 #ifdef mingw32_TARGET_OS
4157 These macros are set by the configure script (via the file config.h).
4158 Which is which? The criterion is this. In the ifdefs in GHC's source code:
4161 The "host" system is the one on which GHC itself will be run.
4164 The "target" system is the one for which the program compiled by GHC will be run.
4167 For a stage-2 compiler, in which GHCi is available, the "host" and "target" systems must be the same.
4168 So then it doesn't really matter whether you use the HOST_OS or TARGET_OS cpp macros.
4173 <sect3><title>Summary</title>
4175 <para>Notice that "GHC-mingw" means "GHC that <emphasis>targets</emphasis> MinGW". It says nothing about
4176 how that GHC was <emphasis>built</emphasis>. It is entirely possible to have a GHC-mingw that was built
4177 by compiling GHC's Haskell sources with a GHC-cygwin, or vice versa.</para>
4179 <para>We distribute only a GHC-mingw built by a GHC-mingw; supporting
4180 GHC-cygwin too is beyond our resources. The GHC we distribute
4181 therefore does not require Cygwin to run, nor do the programs it
4182 compiles require Cygwin.</para>
4184 <para>The instructions that follow describe how to build GHC-mingw. It is
4185 possible to build GHC-cygwin, but it's not a supported route, and the build system might
4188 <para>In your build tree, you build a compiler called <Command>ghc-inplace</Command>. It
4189 uses the <Command>gcc</Command> that you specify using the
4190 <option>--with-gcc</option> flag when you run
4191 <Command>configure</Command> (see below).
4192 The makefiles are careful to use <Command>ghc-inplace</Command> (not <Command>gcc</Command>)
4193 to compile any C files, so that it will in turn invoke the right <Command>gcc</Command> rather that
4194 whatever one happens to be in your path. However, the makefiles do use whatever <Command>ld</Command>
4195 and <Command>ar</Command> happen to be in your path. This is a bit naughty, but (a) they are only
4196 used to glom together .o files into a bigger .o file, or a .a file,
4197 so they don't ever get libraries (which would be bogus; they might be the wrong libraries), and (b)
4198 Cygwin and Mingw use the same .o file format. So its ok.
4203 <Sect2><Title>Installing and configuring Cygwin</Title>
4205 <para>You don't need Cygwin to <emphasis>use</emphasis> GHC,
4206 but you do need it to <emphasis>build</emphasis> GHC.</para>
4208 <para> Install Cygwin from <ulink url="http://www.cygwin.com/">http://www.cygwin.com/</ulink>.
4209 The installation process is straightforward; we install it in <Filename>c:/cygwin</Filename>.
4210 During the installation dialogue, make sure that you select:
4211 <command>cvs</command>, <command>openssh</command>,
4212 <command>autoconf</command>,
4213 <command>binutils</command> (includes ld and (I think) ar),
4214 <command>gcc</command>,
4215 <command>flex</command>,
4216 <command>make</command>.
4219 <para> Now set the following user environment variables:
4222 <listitem><para> Add <filename>c:/cygwin/bin</filename> and <filename>c:/cygwin/usr/bin</filename> to your
4223 <constant>PATH</constant></para></listitem>
4227 Set <constant>MAKE_MODE</constant> to <Literal>UNIX</Literal>. If you
4228 don't do this you get very weird messages when you type
4229 <Command>make</Command>, such as:
4231 /c: /c: No such file or directory
4236 <listitem><para> Set <constant>SHELL</constant> to
4237 <Filename>c:/cygwin/bin/sh</Filename>. When you invoke a shell in Emacs, this
4238 <constant>SHELL</constant> is what you get.
4241 <listitem><para> Set <constant>HOME</constant> to point to your
4242 home directory. This is where, for example,
4243 <command>bash</command> will look for your <filename>.bashrc</filename>
4244 file. Ditto <command>emacs</command> looking for <filename>.emacsrc</filename>
4250 There are a few other things to do:
4254 Some script files used in the make system start with "<Command>#!/bin/perl</Command>",
4255 (and similarly for <Command>bash</Command>). Notice the hardwired path!
4256 So you need to ensure that your <Filename>/bin</Filename> directory has the following
4259 <listitem> <para><Command>sh</Command></para></listitem>
4260 <listitem> <para><Command>perl</Command></para></listitem>
4261 <listitem> <para><Command>cat</Command></para></listitem>
4263 All these come in Cygwin's <Filename>bin</Filename> directory, which you probably have
4264 installed as <Filename>c:/cygwin/bin</Filename>. By default Cygwin mounts "<Filename>/</Filename>" as
4265 <Filename>c:/cygwin</Filename>, so if you just take the defaults it'll all work ok.
4266 (You can discover where your Cygwin
4267 root directory <Filename>/</Filename> is by typing <Command>mount</Command>).
4268 Provided <Filename>/bin</Filename> points to the Cygwin <Filename>bin</Filename>
4269 directory, there's no need to copy anything.
4275 By default, cygwin provides the command shell <filename>ash</filename>
4276 as <filename>sh.exe</filename>. It has a couple of 'issues' (to do with quoting
4277 and length of command lines), so
4278 in your <filename>/bin</filename> directory, make sure that <filename>
4279 bash.exe</filename> is also provided as <filename>sh.exe</filename>
4280 (i.e. overwrite the old <filename>sh.exe</filename> with a copy of
4281 <filename>bash.exe</filename>).
4287 <para>Finally, here are some things to be aware of when using Cygwin:
4289 <listitem> <para>Cygwin doesn't deal well with filenames that include
4290 spaces. "<filename>Program Files</filename>" and "<filename>Local files</filename>" are
4294 <listitem> <para> Cygwin implements a symbolic link as a text file with some
4295 magical text in it. So other programs that don't use Cygwin's
4296 I/O libraries won't recognise such files as symlinks.
4297 In particular, programs compiled by GHC are meant to be runnable
4298 without having Cygwin, so they don't use the Cygwin library, so
4299 they don't recognise symlinks.
4303 Win32 has a <command>find</command> command which is not the same as Cygwin's find.
4304 You will probably discover that the Win32 <command>find</command> appears in your <constant>PATH</constant>
4305 before the Cygwin one, because it's in the <emphasis>system</emphasis> <constant>PATH</constant>
4306 environment variable, whereas you have probably modified the <emphasis>user</emphasis> <constant>PATH</constant>
4307 variable. You can always invoke <command>find</command> with an absolute path, or rename it.
4314 <Sect2><Title>Other things you need to install</Title>
4316 <para>You have to install the following other things to build GHC:
4320 Install an executable GHC, from <ulink url="http://www.haskell.org/ghc">http://www.haskell.org/ghc</ulink>.
4321 This is what you will use to compile GHC. Add it in your
4322 <constant>PATH</constant>: the installer tells you the path element
4323 you need to add upon completion.
4329 Install an executable Happy, from <ulink url="http://www.haskell.org/happy">http://www.haskell.org/happy</ulink>.
4330 Happy is a parser generator used to compile the Haskell grammar. Add it in your
4331 <constant>PATH</constant>.
4337 <para>GHC uses the <emphasis>mingw</emphasis> C compiler to
4338 generate code, so you have to install that (see <xref linkend="cygwin-and-mingw">).
4339 Just pick up a mingw bundle at
4340 <ulink url="http://www.mingw.org/">http://www.mingw.org/</ulink>.
4341 We install it in <filename>c:/mingw</filename>.
4343 <para>Do <emphasis>not</emphasis> add any of the <emphasis>mingw</emphasis> binaries to your path.
4344 They are only going to get used by explicit access (via the --with-gcc flag you
4345 give to <Command>configure</Command> later). If you do add them to your path
4346 you are likely to get into a mess because their names overlap with Cygwin binaries.
4352 <para>We use <command>emacs</command> a lot, so we install that too.
4353 When you are in <filename>fptools/ghc/compiler</filename>, you can use
4354 "<literal>make tags</literal>" to make a TAGS file for emacs. That uses the utility
4355 <filename>fptools/ghc/utils/hasktags/hasktags</filename>, so you need to make that first.
4356 The most convenient way to do this is by going <literal>make boot</literal> in <filename>fptools/ghc</filename>.
4357 The <literal>make tags</literal> command also uses <command>etags</command>, which comes with <command>emacs</command>,
4358 so you will need to add <filename>emacs/bin</filename> to your <literal>PATH</literal>.
4364 <para> Finally, check out a copy of GHC sources from
4365 the CVS repository, following the instructions above (<xref linkend="cvs-access">).
4372 <Sect2><Title>Building GHC</Title>
4375 Now go read the documentation above on building from source (<xref linkend="sec-building-from-source">);
4376 the bullets below only tell
4377 you about Windows-specific wrinkles.</para>
4381 Run <Command>autoconf</Command> both in <filename>fptools</filename>
4382 and in <filename>fptools/ghc</filename>. If you omit the latter step you'll
4383 get an error when you run <filename>./configure</filename>:
4386 creating mk/config.h
4387 mk/config.h is unchanged
4389 running /bin/sh ./configure --cache-file=.././config.cache --srcdir=.
4390 ./configure: ./configure: No such file or directory
4391 configure: error: ./configure failed for ghc
4396 <listitem> <para><command>autoconf</command> seems to create the file <filename>configure</filename>
4397 read-only. So if you need to run autoconf again (which I sometimes do for safety's sake),
4400 /usr/bin/autoconf: cannot create configure: permission denied
4402 Solution: delete <filename>configure</filename> first.
4407 You either need to add <filename>ghc</filename> to your
4408 <constant>PATH</constant> before you invoke
4409 <Command>configure</Command>, or use the <Command>configure</Command>
4410 option <option>--with-ghc=c:/ghc/ghc-some-version/bin/ghc</option>.
4415 If you are paranoid, delete <filename>config.cache</filename> if it exists.
4416 This file occasionally remembers out-of-date configuration information, which
4417 can be really confusing.
4423 After <command>autoconf</command> run <command>./configure</command> in
4424 <filename>fptools/</filename> thus:
4427 ./configure --host=i386-unknown-mingw32 --with-gcc=c:/mingw/bin/gcc
4429 This is the point at which you specify that you are building GHC-mingw
4430 (see <xref linkend="ghc-mingw">). </para>
4432 <para> Both these options are important! It's possible to get into
4433 trouble using the wrong C compiler!
4434 Furthermore, it's very important that you specify a
4435 full mingw path for <command>gcc</command>, not a cygwin path, because GHC (which
4436 uses this path to invoke <command>gcc</command>) is a Mingw program and won't
4437 understand a cygwin path.. For example, if you
4438 say <literal>--with-gcc=/mingw/bin/gcc</literal>, it'll be interpreted as
4439 <filename>/cygdrive/c/mingw/bin/gcc</filename>, and GHC will fail the first
4440 time it tries to invoke it. (Worse, the failure does not come with
4441 a helpful error message, unfortunately.)
4445 If you want to build GHC-cygwin (<xref linkend="ghc-cygwin">)
4446 you'll have to do something more like:
4448 ./configure --with-gcc=...the Cygwin gcc...
4453 <listitem><para> Do not attempt to build the documentation.
4454 It needs all kinds of wierd Jade stuff that we haven't worked out for
4455 Win32.</para></listitem>