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Building CMU CL

This document is intended to give you a general overview of the build process (i.e. what needs to be done, in what order, and what is it generally called). It will also tell you how to set up a suitable build environment, how the individual scripts fit into the general scheme of things, and give you a couple of examples.

General Requirements

In order to build CMU CL, you will need:

  1. A working CMU CL binary.

    There is no way around this requirement! This binary can either be for the platform you want to target, in that case you can either recompile or cross-compile, or for another supported platform, in that case you must cross-compile, obviously.

  2. A supported C compiler for the C runtime code.

    Most of the time, this means GNU gcc, though for some ports it means the vendor-supplied C compiler. The compiler must be available under the name specified by your ports Config file.

  3. GNU make.

    This has to be available either as gmake or make in your PATH, or the MAKE environment variable has to be set to point to the correct binary.

  4. The CMU CL source code.

    Here you can either use one of the release source tarballs, or check out the source code directly from the public CMUCL git repository.

If you want to build CMU CL's Motif interface/toolkit, you'll need a working version of the Motif libraries, either true-blue OSF/Motif, or OpenMotif, or LessTif. The code was developed against 1.2 Motif, though recompilation against 2.x Motif probably works as well.

Setting up a build environment

  1. Create a base directory and change to it
        mkdir cmucl ; cd cmucl
  2. Fetch the sources and put them into the base directory
        tar xzf /tmp/cmucl-source.tar.gz

    or, if you want to use the git sources directly:

        git clone git://

    Whatever you do, the sources must be in a directory named src inside the base directory. Since the build tools keep all generated files in separate target directories, the src directory can be read-only (e.g. mounted read-only via NFS, etc.)

    The build tools are all in the bin directory.

That's it, you are now ready to build CMU CL.

A quick guide for simple builds

We recommend that you read all of this document, but in case you don't want to do that and in case you know, somehow, that the version of CMUCL you are building from will build the sources you have, here is a quick guide.

  1. Simple builds

    Use this to build from a version of CMUCL that is very close to the sources you are trying to build now:

       bin/ -C "" -o "<path-to-old-lisp> <options-to-lisp>"

    For example, let's say you want to use the 2012-05 snapshot that you stored in the $HOME/2012-05 directory. Then <path-to-old-lisp> would be $HOME/2012-05/bin/lisp. Usually, no options are needed so <options-to-lisp> is not needed.

    This will build CMUCL 3 times, each time with the result of the previous build. The last time, the additional libraries like CLX, CLM, and Hemlock are built. The final result will be in the directory build-4.

    This script basically runs,, three times. See below for descriptions of these scripts.

  2. Slightly more complicated builds

    For slightly more complicated builds, you may need to use some bootstrap files. See below for more information about these bootstrap files.

    For these, you can use this:

       bin/ -C "" -o "<old-lisp>" -B boot1.lisp -B boot2.lisp

    The bootstrap files listed with the -B option (as many as needed) are loaded in order, so be sure to get them right.

    As in a) above, three builds are done, and the result is in the directory build-4.

  3. More complicated builds

    If you have more complicated builds, this script probably will not work, and definitely does not handle cross-compiles. In this case, you will have to invoke the individual scripts by hand, as described below.

How do you know which of the three options above apply? The easiest way is to look in src/bootfiles/<version>/* for boot files. If the file date of a boot file is later than the version of CMUCL you are building from, then you need to use b) or c) above. You may need to read the bootfiles for additional instructions, if any.

If there are no bootfiles, then you can use a) above.

The script supports other options, and bin/ -? will give a quick summary. Read bin/ for more information.

A general outline of the build process

Building CMU CL can happen in one of two ways: Normal recompilation, and cross-compilation. We'll first look at normal recompilation:

The recompilation process basically consists of 4 phases/parts:

  1. Compiling the lisp files that make up the standard kernel.

    This happens in your current CMU CL process, using your current CMU CL's normal file compiler. This phase currently consists of 3 sub-phases, namely those controlled by src/tools/worldcom.lisp, which compiles all the runtime files, src/tools/comcom.lisp, which compiles the compiler (including your chosen backend), and finally src/tools/pclcom.lisp, which compiles PCL, CMU CL's CLOS implementation. The whole phase is often called "world-compile", or "compiling up a world", based on the name of the first sub-phase.

  2. Building a new kernel.core file out of the so created files

    This process, which is generally called genesis, and which is controlled by src/tools/worldbuild.lisp, uses the newly compiled files in order to build a new, basic core file, which is then used by the last phase to create a fully functional normal core file. It does this by "loading" the compiled files into an in-core representation of a new core file, which is then dumped out to disk, together with lots of fixups that need to happen once the new core is started.

    As part of this process, it also creates the file internals.h, which contains information about the general memory layout of the new core and its basic types, their type tags, and the location of several important constants and other variables, that are needed by the C runtime code to work with the given core.

    So going through genesis is needed to create internals.h, which is needed to compile the C runtime code (i.e. the "lisp" binary). However there is a slight circularity here, since genesis needs as one of its inputs the file target:lisp/lisp.nm, which contains the (slightly pre-treated) output of running nm on the new lisp binary. Genesis uses this information to fixup the addresses of C runtime support functions for calls from Lisp code.

    However the circularity isn't complete, since genesis can work with an empty/bogus lisp.nm file. While the kernel.core it then produces is unusable, it will create a usable internals.h file, which can be used to recompile the C runtime code, producing a usable lisp.nm file, which in turn can be used to restart genesis, producing a working kernel.core file.

    Genesis also checks whether the newly produced internals.h file differs from a pre-existing internals.h file (this might be caused by an empty internals.h file if you are rebuilding for the first time, or by changes in the lisp sources that cause differences in the memory layout of the kernel.core), and informs you of this, so that you can recompile the C runtime code, and restart genesis.

    If it doesn't inform you of this, you can skip directly to the last phase d).

  3. Recompiling the C runtime code, producing the "lisp" binary file

    This step is only needed if you haven't yet got a suitable lisp binary, or if the internals.h file has changed during genesis (of which genesis informs you), or when you made changes to the C sources that you want to take effect.

    Recompiling the C runtime code is controlled by a GNU Makefile, and your target's Config file. It depends on a correct internals.h file as produced by genesis.

    Note that whenever you recompile the runtime code, for whatever reason, you must redo phase b). Note that if you make changes to the C sources and recompile because of this, you can do that before Phase b), so that you don't have to perform that phase twice.

  4. Populating the kernel.core, and dumping a new lisp.core file.

    In this phase, which is controlled by src/tools/worldload.lisp, and hence often called world-load, the kernel.core file is started up using the (possibly new) lisp binary, the remaining files which were compiled in phase a) are loaded into it, and a new lisp.core file is dumped out.

We're not quite done yet. This produces just a basic lisp.core. To complete the build so that you something similar to what the releases of CMUCL do, there are a few more steps:

  1. Build the utilities like Gray streams, simple streams, CLX, CLM, and Hemlock. Use the bin/ script for this, as described below
  2. Create tarfiles using the bin/ script, as explained below.

With these tarfiles, you can install them anywhere. The contents of the tarfiles will be the same as the snapshots and releases of CMUCL.

When cross-compiling, there is additional phase at the beginning, and some of the phases happen with different hosts/platforms. The initial phase is setting up and compiling the cross-compilation backend, using your current compiler. The new backend is then loaded, and all compilation in phase a) happens using this compiler backend. The creation of the kernel.core file in phase b) happens as usual, while phase c) of course happens on the target platform (if that differs from the host platform), as does the final phase d). Another major difference is that you can't compile PCL using the cross-compiler, so one usually does a normal rebuild using the cross-compiled core on the target platform to get a full CMU CL core.

So, now you know all about CMU CL compilation, how does that map onto the scripts included with this little text?

Overview of the included build scripts

bin/ [-123obvuBCU?]
This is the main build script. It essentially calls the other build scripts described below in the proper sequence to build cmucl from an existing binary of cmucl.
bin/ target-directory [lisp-variant [motif-variant]]
This script creates a new target directory, which is a shadow of the source directory, that will contain all the files that are created by the build process. Thus, each target's files are completely separate from the src directory, which could, in fact, be read-only. Hence you can simultaneously build CMUCL for different targets from the same source directory.

The first argument is the name of the target directory to create. The remaining arguments are optional. If they are not given, the script tries to determine the lisp variant and motif variant from the system the script is running on.

The lisp-variant (i.e. the suffix of the src/lisp/Config.* to use as the target's Config file), and optionally the motif-variant (again the suffix of the src/motif/server/Config.* file to use as the Config file for the target's CMUCL/Motif server code). If the lisp-variant is given but the motif-variant is not, the motif-variant is determined from the lisp-variant.

The script will generate the target directory tree, link the relevant Config files, and generate place-holder files for various files, in order to ensure proper operation of the other build-scripts. It also creates a sample setenv.lisp file in the target directory, which is used by the build and load processes to set up the correct list of *features* for your target lisp core.

IMPORTANT: You will normally NOT have to modify the sample setenv.lisp file, if you are building from a binary that has the desired features. In fact, the sample has all code commented out, If you want to add or remove features, you need to include code that puts at least a minimal set of features onto the list (use PUSHNEW and/or REMOVE). You can use the current set of *features* of your lisp as a first guide. The sample setenv.lisp includes a set of features that should work for the intended configuration. Note also that some adding or removing some features may require a cross-compile instead of a normal compile.

bin/ [-l] target-directory [more dirs]
Cleans the given target directory, so that all created files will be removed. This is useful to force recompilation. If the -l flag is given, then the C runtime is also removed, including all the lisp executable, any lisp cores, all object files, lisp.nm, internals.h, and the config file.
bin/ target-directory [build-binary] [build-flags...]
Starts a complete world build for the given target, using the lisp binary/core specified as a build host. The recompilation step will only recompile changed files, or files for which the fasl files are missing. It will also not recompile the C runtime code (the lisp binary). If a (re)compilation of that code is needed, the genesis step of the world build will inform you of that fact. In that case, you'll have to use the script, and then restart the world build process with
bin/ target-directory
This script will force a complete recompilation of the C runtime code of CMU CL (aka the lisp executable). Doing this will necessitate building a new kernel.core file, using
bin/ target-directory version
This will finish the CMU CL rebuilding process, by loading the remaining compiled files generated in the world build process into the kernel.core file, that also resulted from that process, creating the final lisp.core file.

You have to pass the version string as a second argument. The dumped core will anounce itself using that string. Please don't use a string consisting of an official release name only, (e.g. "18d"), since those are reserved for official release builds. Including the build-date in ISO8601 format is often a good idea, e.g. "18d+ 2002-05-06" for a binary that is based on sources current on the 6th May, 2002, which is post the 18d release.

bin/ target-directory
This script will build auxiliary libraries packaged with CMU CL, including CLX, CMUCL/Motif, the Motif debugger, inspector, and control panel, and the Hemlock editor. It will use the lisp executable and core of the given target.
bin/ [-bg] [-G group] [-O owner] target-directory version arch os
This script creates both main and extra distribution tarballs from the given target directory, using the and scripts. The result will be two tar files. One contains the main distribution including the runtime and lisp.core with PCL (CLOS); the second contains the extra libraries such as Gray-streams, simple-streams, CLX, CLM, and Hemlock.

Some options that are available:

-b Use bzip2 compression -g Use gzip compression -G group Group to use -O owner Owner to use

If you specify both -b and -g, you will get two sets of tarfiles. The -G and -O options will attempt to set the owner and group of the files when building the tarfiles. This way, when you extract the tarfiles, the owner and group will be set as specified. You may need to be root to do this because many Unix systems don't normally let you change the owner and group of a file.

The remaining arguments used to create the name of the tarfiles. The names will have the form:


Of course, the "bz2" will be "gz" if you specified gzip compression instead of bzip.

/bin/ target-directory version arch os
This is script is not normally invoked by the user; make-dist will do it appropriately.

This script creates a main distribution tarball (both in gzipped and bzipped variants) from the given target directory. This will include all the stuff that is normally included in official release tarballs such as lisp.core and the PCL libraries, including Gray streams and simple streams.

This is intended to be run from

bin/ target-directory version arch os
This is script is not normally invoked by the user; make-dist will do it appropriately.

This script creates an extra distribution tarball (both in gzipped and bzipped variants) from the given target directory. This will include all the stuff that is normally included in official extra release tarballs, i.e. the auxiliary libraries such as CLX, CLM, and Hemlock. target-directory cross-directory cross-script [build-binary] [build-flags...]
This is a script that can be used instead of for cross-compiling CMUCL. In addition to the arguments of it takes two further required arguments: The name of a directory that will contain the cross-compiler backend (the directory is created if it doesn't exist, and must not be the same as the target-directory), and the name of a Lisp cross-compilation script, which is responsible for setting up, compiling, and loading the cross-compiler backend. The latter argument is needed because each host/target combination of platform's needs slightly different code to produce a working cross-compiler.

We include a number of working examples of cross-compiler scripts in the cross-scripts directory. You'll have to edit the features section of the given scripts, to specify the features that should be removed from the current set of features in the host lisp, and those that should be added, so that the backend features are correct for the intended target.

You can look at Eric Marsden's collection of build scripts for the basis of more cross-compiler scripts.

Step-by-Step Example of recompiling CMUCL for OpenBSD

Set up everything as described in the setup section above. Then execute:

# Create a new target directory structure/config for OpenBSD:
bin/ openbsd OpenBSD_gencgc OpenBSD

# edit openbsd/setenv.lisp to contain what we want:
cat <<EOF > openbsd/setenv.lisp
;;; Put code to massage *features* list here...

(in-package :user)

(pushnew :openbsd *features*)
(pushnew :bsd *features*)
(pushnew :i486 *features*)
(pushnew :mp *features*)
(pushnew :hash-new *features*)
(pushnew :random-mt19937 *features*)
(pushnew :conservative-float-type *features*)
(pushnew :gencgc *features*)

;;; Version tags

(pushnew :cmu18d *features*)
(pushnew :cmu18 *features*)
(setf *features* (remove :cmu17 *features*))
(setf *features* (remove :cmu18c *features*))

# Recompile the lisp world, and dump a new kernel.core:
bin/ openbsd lisp # Or whatever you need to invoke your 
                              # current lisp binary+core

# If build-world tells you (as it will the first time) that:
# "The C header file has changed. Be sure to re-compile the startup
# code."
# You 'll need to start to do that, and then reinvoke

# Recompile lisp binary itself:
bin/ openbsd

# Restart now:
bin/ openbsd lisp

# Now we populate the kernel.core with further compiled files,
# and dump the final lisp.core file:

bin/ openbsd "18d+ 2002-05-06"

# The second argument above is the version number that the built
# core will announce.  Please always put the build-date and some
# other information in there, to make it possible to differentiate
# those builds from official builds, which only contain the release.

Now you should have a new lisp.core, which you can start with

./openbsd/lisp/lisp -core ./openbsd/lisp/lisp.core -noinit -nositeinit

Compiling sources that contain disruptive changes

The above instructions should always work as-is for recompiling CMU CL using matching binaries and source files. They also work quite often when recompiling newer sources. However, every so often, some change to the CMU CL sources necessitates some form of bootstrapping, so that binaries built from earlier sources can compile the sources containing that change. There are two forms of boostrapping that can be required:

  1. Bootfiles

    The maintainers try to make bootfiles available, that allow going from an old release to the next release. These are located in the src/bootfiles/

    I.e. if you have binaries that match release 18d, then you'll need to use all the bootfiles in src/bootfiles/18d/ in order to go to the next release (or current sources, if no release has been made yet). If you already used some of the bootstrap files to compile your current lisp, you obviously don't need to use those to get to later versions.

    You can use the bootfiles by concatenating them into a file called bootstrap.lisp in the target directory (i.e. target:bootstrap.lisp) in the order they are numbered. Be sure to remove the bootstrap file once it is no longer needed.

    Alternatively, the bootstrap file can just "load" the individual bootfiles as needed.

  2. Cross-compiling

    Under some circumstances, bootstrap code will not be sufficient, and a cross-compilation is needed. In that case you will have to use, instead of Please read the instructions of that script for details of the more complex procedure.

    << This isn't really true anymore, and we should place a more elaborate description of the cross-compiling process here >>

    When cross-compiling, there are two sorts of bootscripts that can be used: Those that want to be executed prior to compiling and loading the cross-compiler, which should be placed in the file called target:cross-bootstrap.lisp, and those that should happen after the cross-compiler has been compiled and loaded, just prior to compiling the target, which should be placed in target:bootstrap.lisp, just like when doing a normal recompile.

    Additionally, sometimes customized cross-compiler setup scripts (to be used in place of e.g. cross-x86-x86.lisp) are required, which are also placed in one of the bootfiles/*/* files. In those cases follow the instructions provided in that file, possibly merging the changed contents thereof with your normal cross-script.

Step-by-Step Example of Cross-Compiling

This gives a step-by-step example of cross-compiling a sparc-v8 build using a sparc-v9 build. (For some unknown reason, you can't just remove the :sparc-v9 feature and add :sparc-v8.)

So, first get a recent sparc-v9 build. It's best to get a version that is up-to-date with the sources. Otherwise, you may also need to add a bootstrap file to get any bootfiles to make your lisp up-to-date with the current sources.

  1. Select a directory for the cross-compiler and compiled target:

    Create a cross-compiler directory to hold the cross-compiler and a target directory to hold the result:

    	       bin/ xcross
    	       bin/ xtarget
  2. Adjust cross-compilation script

    Copy the src/tools/cross-scripts/cross-sparc-sparc.lisp to xtarget/cross.lisp. Edit it appropriately. In this case, it should look something like:

    	    (c::new-backend "SPARC"
    	       ;; Features to add here
    	       '(:sparc :sparc-v8
    		 :hash-new :random-mt19937
    		 :cmu :cmu19 :cmu19a
    	       ;; Features to remove from current *features* here
    	       '(:sparc-v9 :sparc-v7 :x86 :x86-bootstrap :alpha :osf1 :mips
    		 :propagate-fun-type :propagate-float-type :constrain-float-type
    		 :openbsd :freebsd :glibc2 :linux :pentium
    		 :long-float :new-random :small))
    	    (setf *features* (remove :sparc-v9 *features*))
    	    (pushnew :sparc-v8 *features*)
    It's important to add frob *features* here as well as in the new-backend. If you don't adjust *features*, they won't be set appropriately in the result.
  3. Build the cross compiler and target

    Now compile the result:

    	    bin/ xtarget xcross xtarget/cross.lisp [v9 binary]
  4. Rebuild the lisp files:

    When this finishes, you need to compile the C code:

    		bin/ xtarget

    At this point, you may want to run again to generate a new kernel.core. It shouldn't build anything; just loads everything and creates a kernel.core.

  5. Build the world:

    With the new kernel.core, we need to create a lisp.core:

    		bin/ xtarget "new lisp"

    Test the result with

    		xtarget/lisp/lisp -noinit

However, this lisp will be missing some functionality like PCL. You probably now want to use the compiler to rebuild everything once again. Just follow the directions for a normal build, and use xtarget/lisp/lisp as your compiler. Be sure to use to create a new directory where the result can go.

Cross-Platform Cross-Compile

A cross-platform cross-compile is very similar to a normal cross-compile, and the basic steps are the same. For the sake of concreteness, assume we are on ppc/darwin and want to cross-compile to x86/linux.

To simplify things, we assume that both platforms have access to the same file system, via NFS or something else.

  1. As above, we need to create directories for the cross-compiler and compiled target. We assume we are on ppc/darwin. So, when running we need to specify the target:
            bin/ x86-cross x86
            bin/ x86-target x86
  2. Adjust the cross-compilation script. An example for ppc/darwin to x86/linux is in src/tools/cross-scripts/cross-ppc-x86.lisp.
  3. Build the cross compiler and target, as above, using the specified cross-compile script:
            bin/ x86-target x86-cross cross.lisp [ppc binary]
    where cross.lisp is the cross-compile script from 2) above.
  4. Everything has now been compiled for the x86/linux target. We need to compile the C code for x86 and create a lisp.core from the kernel.core. This is where it's useful to have both platforms be able to access the same file system. If not, you will need to copy all of the generated files from ppc/darwin to x86/linux. Basically everything in xtarget needs to be copied.

    Note carefully that you may have to edit lisp/internals.h and/or lisp/ to have the correct features. This is a known bug in the generation of these files during cross-compilation.

    Compile the lisp code:
            bin/ x86-target   
  5. Now run to create the desired lisp.core from lisp and kernel.core. As above, PCL has not been compiled, so select restart 3 (return nil from pclload) to create lisp.core
            bin/ x86-target "new x86"

At this point, you will have a shiny new lisp on the new platform. Since it's missing PCL, you will need to do at least one normal build to get PCL included. This is also a good check to see if everything was compiled properly. A full set of builds via might be good at this point too.

Some of the details for each command may have changed; You can get help for each command by using the -h argument.

In particular steps 3, 4, and 5 can be combined into one by using the -c, -r, and -l options for The -c option cleans out the targe and cross directories; -r does step 4; and -l does step 5.

Last modified 2 years ago Last modified on 10/12/14 16:28:48