62 lines
3.1 KiB
Plaintext
62 lines
3.1 KiB
Plaintext
@c Copyright (C) 2001, 2002, 2004 Free Software Foundation, Inc.
|
|
@c This is part of the GCC manual.
|
|
@c For copying conditions, see the file gcc.texi.
|
|
|
|
@node Configure Terms
|
|
@section Configure Terms and History
|
|
@cindex configure terms
|
|
@cindex canadian
|
|
|
|
The configure and build process has a long and colorful history, and can
|
|
be confusing to anyone who doesn't know why things are the way they are.
|
|
While there are other documents which describe the configuration process
|
|
in detail, here are a few things that everyone working on GCC should
|
|
know.
|
|
|
|
There are three system names that the build knows about: the machine you
|
|
are building on (@dfn{build}), the machine that you are building for
|
|
(@dfn{host}), and the machine that GCC will produce code for
|
|
(@dfn{target}). When you configure GCC, you specify these with
|
|
@option{--build=}, @option{--host=}, and @option{--target=}.
|
|
|
|
Specifying the host without specifying the build should be avoided, as
|
|
@command{configure} may (and once did) assume that the host you specify
|
|
is also the build, which may not be true.
|
|
|
|
If build, host, and target are all the same, this is called a
|
|
@dfn{native}. If build and host are the same but target is different,
|
|
this is called a @dfn{cross}. If build, host, and target are all
|
|
different this is called a @dfn{canadian} (for obscure reasons dealing
|
|
with Canada's political party and the background of the person working
|
|
on the build at that time). If host and target are the same, but build
|
|
is different, you are using a cross-compiler to build a native for a
|
|
different system. Some people call this a @dfn{host-x-host},
|
|
@dfn{crossed native}, or @dfn{cross-built native}. If build and target
|
|
are the same, but host is different, you are using a cross compiler to
|
|
build a cross compiler that produces code for the machine you're
|
|
building on. This is rare, so there is no common way of describing it.
|
|
There is a proposal to call this a @dfn{crossback}.
|
|
|
|
If build and host are the same, the GCC you are building will also be
|
|
used to build the target libraries (like @code{libstdc++}). If build and host
|
|
are different, you must have already build and installed a cross
|
|
compiler that will be used to build the target libraries (if you
|
|
configured with @option{--target=foo-bar}, this compiler will be called
|
|
@command{foo-bar-gcc}).
|
|
|
|
In the case of target libraries, the machine you're building for is the
|
|
machine you specified with @option{--target}. So, build is the machine
|
|
you're building on (no change there), host is the machine you're
|
|
building for (the target libraries are built for the target, so host is
|
|
the target you specified), and target doesn't apply (because you're not
|
|
building a compiler, you're building libraries). The configure/make
|
|
process will adjust these variables as needed. It also sets
|
|
@code{$with_cross_host} to the original @option{--host} value in case you
|
|
need it.
|
|
|
|
The @code{libiberty} support library is built up to three times: once
|
|
for the host, once for the target (even if they are the same), and once
|
|
for the build if build and host are different. This allows it to be
|
|
used by all programs which are generated in the course of the build
|
|
process.
|