This section describes what files get installed where. You don't need to know it if you are simply installing GHC, but it is vital information if you are changing the implementation.
GHC is installed in two directory trees:
known as $(libdir), holds all the
support files needed to run GHC. On Unix, this
directory is usually something like /usr/lib/ghc/ghc-5.02.
known as $(bindir), holds executables that
the user is expected to invoke.
Notably, it contains
ghc and ghci. On Unix, this directory
can be anywhere, but is typically something like /usr/local/bin. On Windows,
however, this directory must be $(libdir)/bin.
When GHC runs, it must know where its library directory is. It finds this out in one of two ways:
$(libdir) is passed to GHC using the -B flag.
On Unix (but not Windows), the installed ghc is just a one-line
shell script that invokes the real GHC, passing a suitable -B flag.
[All the user-supplied flags
follow, and a later -B flag overrides an earlier one, so a user-supplied
one wins.]
On Windows (but not Unix), if no -B flag is given, GHC uses a system
call to find the directory in which the running GHC executable lives, and derives
$(libdir) from that. [Unix lacks such a system call.]
That is why $(bindir) must be $(libdir)/bin.
The binary directory, $(bindir), contains user-visible
executables, notably ghc and ghci.
You should add it to your $PATH.
On Unix, the user-invokable ghc invokes $(libdir)/ghc-,
passing a suitable version-B flag to tell ghc- where
version$(libdir) is.
Similarly ghci, except the extra flag --interactive is passed.
On Win32, the user-invokable ghc binary
is the Real Thing (no intervening
shell scripts or .bat files).
Reason: we sometimes invoke GHC with very long command lines,
and cmd.exe (which executes .bat files)
truncates them. Similarly ghci is a C wrapper program that invokes ghc --interactive
(passing on all other arguments), not a .bat file.
The layout of the library directory, $(libdir),
is almost identical on
Windows and Unix, as follows. Differences between Windows and Unix
are annotated [Win32 only] and are commented below.
$(libdir)/
package.conf GHC package configuration
ghc-usage.txt Message displayed by ghc ––help
ghci-usage.txt Message displayed by ghci ––help
bin/ [Win32 only] User-visible binaries
ghc.exe
ghci.exe
unlit Remove literate markup
touchy.exe [Win32 only]
perl.exe [Win32 only]
gcc.exe [Win32 only]
ghc-x.xx GHC executable [Unix only]
ghc-split Asm code splitter
ghc-asm Asm code mangler
gcc-lib/ [Win32 only] Support files for gcc
specs gcc configuration
cpp0.exe gcc support binaries
as.exe
ld.exe
crt0.o Standard
..etc.. binaries
libmingw32.a Standard
..etc.. libraries
*.h Include files
hslibs-imports/ GHC interface files for the...
ghc/*.hi ...'ghc' library
include/ C header files
StgMacros.h GHC-specific
..etc.. header files
mingw/*.h [Win32 only] Mingwin header files
lib/ GHC's library
base-2.1
..etc..
libHSrts*.a GHC RTS archive
libHSghc.a GHC package archive
HSrts.o GHC RTS linkable, used by ghci
HSghc.o GHC package linkable, used by ghci
Note that:
$(libdir) also contains support
binaries. These are not expected to be
on the user's PATH, but are invoked
directly by GHC. In the Makefile system, this directory is
also called $(libexecdir), but
you are not free to change it. It must
be the same as $(libdir).
We distribute gcc with the Win32 distribution of GHC, so that users
don't need to install gcc, nor need to care about which version it is.
All gcc's support files are kept in $(libdir)/gcc-lib/.
Similarly, we distribute perl and a touch
replacement (touchy.exe)
with the Win32 distribution of GHC.
The support programs ghc-split
and ghc-asm are Perl scripts. The
first line says #!/usr/bin/perl; on Unix, the
script is indeed invoked as a shell script, which invokes
Perl; on Windows, GHC invokes
$(libdir)/perl.exe directly, which
treats the #!/usr/bin/perl as a comment.
Reason: on Windows we want to invoke the Perl distributed
with GHC, rather than assume some installed one.