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author | Joseph Myers <jsm28@cam.ac.uk> | 2001-11-12 15:46:48 +0000 |
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committer | Joseph Myers <jsm28@gcc.gnu.org> | 2001-11-12 15:46:48 +0000 |
commit | 73a8ed7ed443bcdcc57cd2d29fe15a44c0cf56cd (patch) | |
tree | 7ce809932fcd2257692c59cd13c2e788c4e9896a /gcc/doc/configterms.texi | |
parent | 285a5742c0cc7d86f78dca98ee0287ae6511d16d (diff) | |
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gcc.texi: Move several chapters out to ...
* doc/gcc.texi: Move several chapters out to ...
* doc/configterms.texi, doc/fragments.texi, doc/hostconfig.texi,
doc/include/linux-and-gnu.texi, doc/interface.texi,
doc/makefile.texi, doc/passes.texi, doc/portability.texi:
... here. New files.
* doc/gcc.texi, doc/contrib.texi: Move section headings into
contrib.texi.
* Makefile.in ($(docdir)/gcc.info, gcc.dvi): Update dependencies.
From-SVN: r46951
Diffstat (limited to 'gcc/doc/configterms.texi')
-rw-r--r-- | gcc/doc/configterms.texi | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/gcc/doc/configterms.texi b/gcc/doc/configterms.texi new file mode 100644 index 0000000..a40fbe0 --- /dev/null +++ b/gcc/doc/configterms.texi @@ -0,0 +1,65 @@ +@c Copyright (C) 2001 Free Software Foundation, Inc. +@c This is part of the GCC manual. +@c For copying conditions, see the file gcc.texi. + +@section Configure Terms and History +@cindex configure terms +@cindex canadian + +This section is not instructions for building GCC. If you are trying to +do a build, you should first read @uref{http://gcc.gnu.org/install/} or +whatever installation instructions came with your source package. + +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 say of describing it +(although I propose calling it 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. + +Libiberty, for example, is built twice. The first time, host comes from +@option{--host} and the second time host comes from @option{--target}. +Historically, libiberty has not been built for the build machine, +though, which causes some interesting issues with programs used to +generate sources for the build. Fixing this, so that libiberty is built +three times, has long been on the to-do list. |