1 File.........: 3 - Configuring a toolchain.txt
2 Copyrigth....: (C) 2010 Yann E. MORIN <yann.morin.1998@anciens.enib.fr>
3 License......: Creative Commons Attribution Share Alike (CC-by-sa), v2.5
7 Configuring crosstool-NG /
8 _________________________/
11 crosstool-NG is configured with a configurator presenting a menu-stuctured set
12 of options. These options let you specify the way you want your toolchain
13 built, where you want it installed, what architecture and specific processor it
14 will support, the version of the components you want to use, etc... The
15 value for those options are then stored in a configuration file.
17 The configurator works the same way you configure your Linux kernel. It is
18 assumed you now how to handle this.
20 To enter the menu, type:
23 Almost every config item has a help entry. Read them carefully.
25 String and number options can refer to environment variables. In such a case,
26 you must use the shell syntax: ${VAR}. You shall neither single- nor double-
27 quote the string/number options.
29 There are three environment variables that are computed by crosstool-NG, and
33 It represents the target tuple you are building for. You can use it for
34 example in the installation/prefix directory, such as:
35 /opt/x-tools/${CT_TARGET}
38 The top directory where crosstool-NG is running. You shouldn't need it in
39 most cases. There is one case where you may need it: if you have local
40 patches and you store them in your running directory, you can refer to them
41 by using CT_TOP_DIR, such as:
42 ${CT_TOP_DIR}/patches.myproject
45 The version of crosstool-NG you are using. Not much use for you, but it's
49 Interesting config options |
50 ---------------------------+
52 CT_LOCAL_TARBALLS_DIR:
53 If you already have some tarballs in a direcotry, enter it here. That will
54 speed up the retrieving phase, where crosstool-NG would otherwise download
58 This is where the toolchain will be installed in (and for now, where it
59 will run from). Common use is to add the target tuple in the directory
60 path, such as (see above):
61 /opt/x-tools/${CT_TARGET}
64 An identifier for your toolchain, will take place in the vendor part of the
65 target tuple. It shall *not* contain spaces or dashes. Usually, keep it
66 to a one-word string, or use underscores to separate words if you need.
67 Avoid dots, commas, and special characters.
70 An alias for the toolchian. It will be used as a prefix to the toolchain
71 tools. For example, you will have ${CT_TARGET_ALIAS}-gcc
73 Also, if you think you don't see enough versions, you can try to enable one of
77 Show obsolete versions or tools. Most of the time, you don't want to base
78 your toolchain on too old a version (of gcc, for example). But at times, it
79 can come handy to use such an old version for regression tests. Those old
80 versions are hidden behind CT_OBSOLETE. Those versions (or features) are so
81 marked because maintaining support for those in crosstool-NG would be too
82 costly, time-wise, and time is dear.
85 Show experimental versions or tools. Again, you might not want to base your
86 toolchain on too recent tools (eg. gcc) for production. But if you need a
87 feature present only in a recent version, or a new tool, you can find them
88 hidden behind CT_EXPERIMENTAL. Those versions (or features) did not (yet)
89 receive thorough testing in crosstool-NG, and/or are not mature enough to
93 Re-building an existing toolchain |
94 ----------------------------------+
96 If you have an existing toolchain, you can re-use the options used to build it
97 to create a new toolchain. That needs a very little bit of effort on your side
98 but is quite easy. The options to build a toolchain are saved with the
99 toolchain, and you can retrieve this configuration by running:
100 ${CT_TARGET}-ct-ng.config
102 An alternate method is to extract the configuration from a build.log file.
103 This will be necessary if your toolchain was build with crosstool-NG prior
104 to 1.4.0, but can be used with build.log files from any version:
105 ct-ng extractconfig <build.log >.config
107 Or, if your build.log file is compressed (most probably!):
108 bzcat build.log.bz2 |ct-ng extractconfig >.config
110 The above commands will dump the configuration to stdout, so to rebuild a
111 toolchain with this configuration, just redirect the output to the
113 ${CT_TARGET}-ct-ng.config >.config
116 Then, you can review and change the configuration by running:
120 Using as a backend for a build-system |
121 --------------------------------------+
123 Crosstool-NG can be used as a backend for an automated build-system. In this
124 case, some components that are expected to run on the target (eg. the native
125 gdb, ltrace, DUMA...) are not available in the menuconfig, and they are not
126 build either, as it is considered the responsibility of the build-system to
127 build its own versions of those tools.
129 If you want to use crosstool-NG as a backend to generate your toolchains for
130 your build-system, you have to set and export this environment variable:
133 (case is not sensitive, you can say Y).