genesis.html 4.2 KB
Newer Older
chak's avatar
chak committed
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN">
<html>
  <head>
    <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1">
    <title>The GHC Commentary - Outline of the Genesis</title>
  </head>

  <body BGCOLOR="FFFFFF">
    <h1>The GHC Commentary - Outline of the Genesis</h1>
    <p>
      Building GHC happens in two stages: First you have to prepare the tree
      with <code>make boot</code>; and second, you build the compiler and
      associated libraries with <code>make all</code>.  The <code>boot</code>
      stage builds some tools used during the main build process, generates
      parsers and other pre-computed source, and finally computes dependency
      information.  There is considerable detail on the build process in GHC's
      <a
	href="http://haskell.cs.yale.edu/ghc/docs/latest/building/building-guide.html">Building Guide.</a>

    <h4>Debugging the Beast</h4>
    <p>
      If you are hacking the compiler or like to play with unstable
      development versions, chances are that the compiler someday just crashes
      on you.  Then, it is a good idea to load the <code>core</code> into
      <code>gdb</code> as usual, but unfortunately there is usually not too
      much useful information.
    <p>
      The next step, then, is somewhat tedious.  You should build a compiler
      producing programs with a runtime system that has debugging turned on
      and use that to build the crashing compiler.  There are many sanity
      checks in the RTS, which may detect inconsistency before they lead to a
      crash and you may include more debugging information, which helps
      <code>gdb.</code>  For a RTS with debugging turned on, add the following
      to <code>build.mk</code> (see also the comment in
      <a
      href="http://cvs.haskell.org/cgi-bin/cvsweb.cgi/fptools/mk/config.mk.in"><code>config.mk.in</code></a> that you find when searching for
      <code>GhcRtsHcOpts</code>):
<blockquote><pre>
GhcRtsHcOpts+=-optc-DDEBUG
40
GhcRtsCcOpts+=-g
chak's avatar
chak committed
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
EXTRA_LD_OPTS=-lbfd -liberty</pre></blockquote>
    <p>
      Then go into <code>fptools/ghc/rts</code> and <code>make clean boot &&
      make all</code>.  With the resulting runtime system, you have to re-link
      the compiler.  Go into <code>fptools/ghc/compiler</code>, delete the
      file <code>hsc</code> (up to version 4.08) or
      <code>ghc-&lt;version&gt;</code>, and execute <code>make all</code>.
    <p>
      The <code>EXTRA_LD_OPTS</code> are necessary as some of the debugging
      code uses the BFD library, which in turn requires <code>liberty</code>.
      I would also recommend (in 4.11 and from 5.0 upwards) adding these linker
      options to the files <code>package.conf</code> and
      <code>package.conf.inplace</code> in the directory
      <code>fptools/ghc/driver/</code> to the <code>extra_ld_opts</code> entry
      of the package <code>RTS</code>.  Otherwise, you have to supply them
      whenever you compile and link a program with a compiler that uses the
      debugging RTS for the programs it produces.
    <p>
      To run GHC up to version 4.08 in <code>gdb</code>, first invoke the
      compiler as usual, but pass it the option <code>-v</code>.  This will
      show you the exact invocation of the compiler proper <code>hsc</code>.
      Run <code>hsc</code> with these options in <code>gdb</code>.  The
      development version 4.11 and stable releases from 5.0 on do no longer
      use the Perl driver; so, you can run them directly with gdb.
    <p>
      <strong>Debugging a compiler during building from HC files.</strong> 
      If you are boot strapping the compiler on new platform from HC files and
      it crashes somewhere during the build (e.g., when compiling the
      libraries), do as explained above, but you may have to re-configure the
      build system with <code>--enable-hc-boot</code> before re-making the
      code in <code>fptools/ghc/driver/</code>.
      If you do this with a compiler up to version 4.08, run the build process
      with <code>make EXTRA_HC_OPTS=-v</code> to get the exact arguments with
      which you have to invoke <code>hsc</code> in <code>gdb</code>.

    <p><small>
<!-- hhmts start -->
78
Last modified: Sun Apr 24 22:16:30 CEST 2005
chak's avatar
chak committed
79
80
81
82
<!-- hhmts end -->
    </small>
  </body>
</html>