<title>Porting GHC</title>
<para>This section describes how to port GHC to a currenly
- unsupported platform. There are two distinct
- possibilities:</para>
+ unsupported platform. To avoid confusion, when we say
+ “architecture” we are referring to the processor, and
+ we use the term “platform” to refer to the combination
+ of architecture and operating system.</para>
+
+ <para>There are two distinct porting scenarios:</para>
<itemizedlist>
<listitem>
- <para>The hardware architecture for your system is already
- supported by GHC, but you're running an OS that isn't
- supported (or perhaps has been supported in the past, but
- currently isn't). This is the easiest type of porting job,
- but it still requires some careful bootstrapping. Proceed to
- <xref linkend="sec-booting-from-hc"/>.</para>
+ <para>Your platform is already supported, but you want to
+ compile up GHC using just a C compiler. This is a
+ straightforward bootstrap from HC files, and is described in
+ <xref linkend="sec-booting-from-hc" />.</para>
</listitem>
<listitem>
- <para>Your system's hardware architecture isn't supported by
- GHC. This will be a more difficult port (though by comparison
- perhaps not as difficult as porting gcc). Proceed to <xref
- linkend="unregisterised-porting"/>.</para>
+ <para>Your platform isn't supported by GHC. You will need to
+ do an <emphasis>unregisterised bootstrap</emphasis>, proceed
+ to <xref linkend="unregisterised-porting"/>.</para>
</listitem>
</itemizedlist>
later.</emphasis></para>
<para>HC files are platform-dependent, so you have to get a set
- that were generated on <emphasis>the same platform</emphasis>. There
- may be some supplied on the GHC download page, otherwise you'll have to
- compile some up yourself, or start from
- <emphasis>unregisterised</emphasis> HC files - see <xref
- linkend="unregisterised-porting"/>.</para>
+ that were generated on <emphasis>the same platform</emphasis>.
+ There may be some supplied on the GHC download page, otherwise
+ you'll have to compile some up yourself.</para>
<para>The following steps should result in a working GHC build
with full libraries:</para>
<itemizedlist>
<listitem>
- <para>Unpack the HC files on top of a fresh source tree
- (make sure the source tree version matches the version of
- the HC files <emphasis>exactly</emphasis>!). This will
- place matching <filename>.hc</filename> files next to the
- corresponding Haskell source (<filename>.hs</filename> or
- <filename>.lhs</filename>) in the compiler subdirectory
- <filename>ghc/compiler</filename> and in the libraries
- (subdirectories of
+ <para>Make a set of HC files. On an identical system with
+ GHC already installed, get a GHC source tree and put the
+ following in <literal>mk/build.mk</literal>:</para>
+
+<programlisting>
+SRC_HC_OPTS = -H32m -O -fasm -Rghc-timing -keep-hc-files
+GhcLibHcOpts = -O
+GhcLibWays =
+SplitObjs = NO
+</programlisting>
+
+ <para>Build GHC as normal, and then <literal>make
+ hc-file-bundle Project=ghc</literal> to creates the tar file
+ containing the hc files.</para>
+ </listitem>
+
+ <listitem>
+ <para>On the target system, unpack the HC files on top of a
+ fresh source tree (make sure the source tree version matches
+ the version of the HC files <emphasis>exactly</emphasis>!).
+ This will place matching <filename>.hc</filename> files next
+ to the corresponding Haskell source
+ (<filename>.hs</filename> or <filename>.lhs</filename>) in
+ the compiler subdirectory <filename>ghc/compiler</filename>
+ and in the libraries (subdirectories of
<literal>libraries</literal>).</para>
</listitem>
</sect2>
<sect2 id="unregisterised-porting">
- <title>Porting GHC to a new architecture</title>
+ <title>Porting GHC to a new platform</title>
- <para>The first step in porting to a new architecture is to get
- an <firstterm>unregisterised</firstterm> build working. An
+ <para>The first step in porting to a new platform is to get an
+ <firstterm>unregisterised</firstterm> build working. An
unregisterised build is one that compiles via vanilla C only.
By contrast, a registerised build uses the following
architecture-specific hacks for speed:</para>
since unregisterised compilation is usually just a step on the
way to a full registerised port, we don't mind too much.</para>
+ <para>You should go through this process even if your
+ architecture is already has registerised support in GHC, but
+ your OS currently isn't supported. In this case you probably
+ won't need to port any of the architecture-specific parts of the
+ code, and you can proceed straight from the unregisterised build
+ to build a registerised compiler.</para>
+
<para>Notes on GHC portability in general: we've tried to stick
to writing portable code in most parts of the system, so it
should compile on any POSIXish system with gcc, but in our
<para>You might need to update
<filename>configure.in</filename> to recognise the new
- architecture, and re-generate
+ platform, and re-generate
<filename>configure</filename> with
<literal>autoreconf</literal>.</para>
</listitem>
<title>GHCi</title>
<para>To support GHCi, you need to port the dynamic linker
- (<filename>$(GHC_TOP)/rts/Linker.c</filename>). The linker
- currently supports the ELF and PEi386 object file formats - if
- your platform uses one of these then things will be
- significantly easier. The majority of Unix platforms use the
- ELF format these days. Even so, there are some
+ (<filename>$(GHC_TOP)/rts/Linker.c</filename>). The
+ linker currently supports the ELF and PEi386 object file
+ formats - if your platform uses one of these then things will
+ be significantly easier. The majority of Unix platforms use
+ the ELF format these days. Even so, there are some
machine-specific parts of the ELF linker: for example, the
code for resolving particular relocation types is
machine-specific, so some porting of this code to your
- architecture will probaly be necessary.</para>
+ architecture and/or OS will probaly be necessary.</para>
<para>If your system uses a different object file format, then
you have to write a linker — good luck!</para>
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