makepp - Online in the Cloud

PROGRAM:

NAME

makepp -- Compatible but improved replacement for make

SYNOPSIS

makepp [ -e ] [ -C dir ] [ -f makefile] [ -F makefile_or_dir ]
[ -j n] [ -k ] [ -m method ] [ --noremake-makefiles ]
[ --nowarn ] [ -q ] [ -R dir] [ --traditional-recursive-make ]
[ -v ] [ --version ] [ VAR=value ... ] [ target ... ]

mpp [-options] [ VAR=value ... ] [ target ... ]

DESCRIPTION

Makepp, a build program which has a number of features that allow for reliable builds and
simpler build files, is a drop-in replacement for GNU make. It supports almost all of the
syntax that GNU make supports, and can be used with makefiles produced by utilities such
as automake. It is called makepp (or make++) because it was designed with special support
for C++, which has since been extended to other languages like Swig or embedded SQL. Also
its relationship to make is analogous to C++'s relationship to C: it is almost 100%
backward compatible but adds a number of new features and much better ways to write
makefiles.

Makepp passes an extensive test-suite, and is used in several big projects. If you have
any issues with the latest CVS version, holler, and we'll try to fix it quickly. Makepp
runs with any version of Perl since 5.8.

The following manual pages contain further information on how to use makepp:

Tutorial
How to write a makefile. This is mostly intended for someone with little or no
experience using any implementation of make.

Compilation Tutorial
What the Unix compilation commands do.

Release Notes
What changed with each release.

Incompatibilities
What works differently between GNU make and makepp.

Speedup
Various tips for making makepp go much faster.

Perl Performance
Various tips for making Perl programming (within your makefiles and elsewhere) go
faster.

Cookbook
Quick answers to "How do I ...?" or "What's the best way to ...?"

FAQ Quick answers to questions people have stumbled upon.

Build Algorithm
How makepp's build algorithm differs in fundamental ways from traditional make.

Build Cache
A build cache is a directory that stores the results of prior builds in case they are
needed again in the same directory, or in a separate build in a different directory.

Build Check Methods
How makepp decides when to build.

Builtin Commands
Powerful, efficient commands available everwhere makepp 2.0 or newer is.

Builtin Rules
For very simple programs, you may not need a makefile at all! These are the builtin
rules that makepp knows about.

Compatibility
Where and and with what version of Perl makepp works.

Extending
How you can add functions to makepp by writing your own Perl code.

Functions
Functions for text manipulation and various other purposes.

Repositories
Repositories are a technique that simplifies both variant builds and keeping a central
set of sources.

Rules
Specifying rules to build files.

Sandboxes
Using sandboxes to partition the build.

Scanning
How makepp scans for dependencies like include files.

Signatures
How makepp decides when files have changed.

Statements
Additional directives to control makepp.

Variables
Using variables to simplify rules.

makepp, mpp
Command line syntax of the main utility.

makeppclean, mppc
An efficient stand-alone cleanup script to remove files generated by makepp.

makeppgraph, mppg
A stand-alone utility to graphically analyze dependencies and the reasons for a
rebuild.

makeppinfo, mppi
A stand-alone utility to readably dump the build info makepp remembers about each
file.

makepplog, mppl
A stand-alone utility to analyze dependencies and the reasons for a rebuild.

makeppreplay, mppr
A stand-alone utility to repeat things makepp has done, but much faster.

Index
All keywords, functions and operators in makepp.

Features
Automatic scanning for include files
Makepp scans automatically for include files. This obviates the need for tools like
makedepend. Makepp's scanner works even if the included files don't exist yet but
have to be built. (This is true no matter where on the include path they come from,
unlike programs that depend on gcc's "-MM -MG" option.) Makepp has a flexible system
for doing this which is based on scanning the build command; you can adapt it for
other languages or build commands by writing a Perl subroutine.

Better system for hierarchical builds
Makepp has a better system for handling builds involving multiple directories and
multiple makefiles. The traditional technique is to have make invoke itself
recursively in each directory. Depending on how complicated the interdependencies
are, several recursive passes are sometimes needed. This makes the makefiles very
complicated if they guarantee a correct build. The real problem is that unless
dependencies are trivial (e.g., just one library file), it is almost impossible to
express accurately dependencies of targets in one makefile in terms of targets from
the other makefile. Unix make isn't smart enough to realize that a target in one
makefile depends on a file that is a target in a lower-level makefile; it can't take
build commands from the lower-level makefile while it is trying to build the target in
the upper-level makefile. So the usual solution is to build everything that can be
built with the lower-level makefiles, hoping that that's adequate to build everything
that's needed for the upper-level makefile.

Makepp loads all the needed makefiles in at once, so it has no problem dealing with
situations where a file from one makefile depends on a file produced by a different
makefile. Makepp cd's automatically to the directory containing the makefile before
executing a command from a makefile, so each makefile may be written independently
without knowledge of the top-level build directory. But if access to the root of your
build tree is important (e.g. because that's where your include directory resides),
you can name the makefile in that directory specially. Then makepp gives you the path
to that directory in a variable.

Makepp also can figure out where all the makefiles for the entire project are without
being told, if each makefile is in the same directory as the files it is supposed to
produce. This can also simplify makefiles a great deal.

For more details on building with multiple directories, see "Tips for multiple
directories" in makepp_cookbook.

Reliable wildcards
Makefiles can use wildcards reliably, because wild cards match either files that
exist, or files that do not yet exist but makepp knows how to build. So even for a
program with dozens of modules, your entire makefile could simply read something like
this:

CXX = g++
CXXFLAGS = -g

%.o : %.c
$(CXX) $(CXXFLAGS) -c $(input) -o $(output)

my_program: *.o
$(CXX) $(inputs) -o $(output)

and this will work even if none of the ".o" files have been built yet.

Reliable builds: remembers build command
Makepp keeps track of the build commands, so that if compilation options change, files
are automatically rebuilt. This is important to guarantee correct builds. (This idea
was taken from Bob Sidebothem's "cons" utility, which was described in the Perl
Journal in 1998 and is available from CPAN.)

To illustrate why this is important, consider the following structure definition:

class ABC {
int x;
#ifndef SPECIAL_OPTION
int y;
#endif
int z;
};

Now suppose you decide to turn on the "SPECIAL_OPTION" option by adding
"-DSPECIAL_OPTION" to the command line. A recompilation of everything is needed, but
a traditional Unix make will not detect this, and will only recompile source files
which have actually changed. As a result, some of your modules will be compiled with
-DSPECIAL_OPTION, and others won't. After a very frustrating debugging session, you
will discover that all that needs to be done is to rebuild everything. Then you will
curse make and hopefully switch to an improved implementation of it, like makepp. At
least, that's what I did.

As another example, suppose that you are working on a project which is pretty well
debugged, so it's usually compiled with "-O2". Now you run into a bug which you need
to look at in the debugger. Code compiled with optimization is difficult to examine
in the debugger, so you want to recompile your code so that you can look at it. If
your makefile is set up to store the compiler options in the usual variables, you can
just do this:

makepp CFLAGS=-g CXXFLAGS=-g

and makepp will know that the command line has changed for all the modules. Then when
you've found your bug, just type

makepp

and it will be recompiled with optimization. You don't need to type "make clean" when
you change build options.

Some makefiles (e.g., those for the Linux kernel) go to incredible lengths to force
recompilation when the compile command changes. With makepp, it's taken care of
automatically--you don't have to do anything.

Reliable builds: exact matching of signature
By default, makepp doesn't merely ensure that all targets are newer than all
dependencies; if you replace a dependency with an older file, makepp knows that it has
to rebuild the target, simply because the input file has changed. This is another
important feature to guarantee correct builds which was taken from the "cons" utility.

Smart signature calculations
Some modifications to source files do not actually require a rebuild. For example, if
you just change a comment line, or if you reindent some code, there is no particular
reason to force a compilation. For C/C++ compilation, makepp determines whether a
file needs recompilation by computing a cryptographic checksum of the file's contents,
ignoring comments and whitespace, instead of looking at the file time.

This is particularly useful if you have include files that are generated by files that
change, and yet the generated include files themselves seldom change. Suppose you
have a complicated yacc grammar in your program, with a build rule like this:

y.tab.c y.tab.h: parser.y
yacc -d parser.y

Ordinarily, every time you make even a tiny change to "parser.y", every file that
depends on "y.tab.h" must be rebuilt since the file time of "y.tab.h" has changed.
However, most changes to "parser.y" won't actually change the contents of "y.tab.h"
(except possibly a comment), so all that recompilation is unnecessary.

Repositories
Makepp can automatically incorporate files from a different directory tree (the
"repository") into the current build tree as needed. (This idea was also taken from
the "cons" program.) This has several interesting uses:

Variant builds
Suppose you have been compiling your program with optimization on and debugging
off. Now a bug crops up and you have to recompile everything with debugging
enabled. Once you find the bug, however, you're going to turn debugging off and
optimization back on, and with most make programs you would have to recompile all
the sources again, even the ones that did not change. The procedure would look
like this:

% makepp CFLAGS=-O2 # Compile everything.
# oops, bug discovered here
% makepp CFLAGS=-g # Recompiles everything again.
gdb my_program
# ... find the bug
% makepp CFLAGS=-O2 # Recompiles everything a third time.

With makepp, you can simply cd to an empty directory, and specify your original
directory as a repository. This will create new object files in the empty
directory, while leaving your old object files intact. Now you can find the bug
in the directory compiled with debug, fix it in your original sources, and then go
back to your original directory. Now only the few files that you changed actually
need to be recompiled.

The entire procedure would look like this:

% makepp CFLAGS=-O2 # Compile everything.
# oops, bug discovered here
% mkdir debugging
% cd debugging
% makepp -R .. CFLAGS=-g # Compile with debugging enabled, but
# put objects in debugging subdir.
% gdb my_program
# ... find the bug
% cd .. # Back to original directory.
% makepp CFLAGS=-O2 # Recompiles only those files
# that you changed.

This can be a tremendous savings in time if there are many modules.

Development team with common sources
Suppose you have a team of developers working on a standard set of sources. Each
developer is making independent changes, but doesn't need to have a copy of the
whole source tree. Using makepp's repositories, you can have each developer have
copies only of the files he has changed. Makepp will automatically and
temporarily create symbolic links for the other files that have not been changed
to the corresponding files in the repository. It can even do this for object
files which exist in the repository and do not need to be recompiled in the
developer's individual directory.

Guarantee correct rules
If your rules do somthing which you didn't tell makepp about, the repository
mechanism will not know to fetch those things. So something that builds normally
but fails from a repository tells you to fix your rules.

Automatic inference of needed ".o" files
Makepp can often infer exactly which objects are actually necessary without being
explicitly told. If you use this feature, then if one of your source file includes
"xx.h", and there is a file called "xx.o" that makepp knows how to make, then makepp
adds "xx.o" to the link command line. I don't use non-shared libraries now in many
places where I used to, because makepp can automatically pick out the modules I need.

Correct handling of aliases for directories
Makepp won't be confused by soft links to a directory or by different relative
filenames that refer to the same file. All directory paths to a file are recognized,
including foo, ./foo, ../src/foo, /auto_mnt/somedisk/bob/src/foo, and
/users/bob/src/foo.

Filenames with special characters
Makepp can support filenames with colons or spaces or other special characters that
cause trouble for the traditional make. Just surround the filename with quotes. (See
"Special characters" in makepp_rules for details.)

Extensible textual substutition functions
Makepp can use arbitrary Perl subroutines for textual substitution in the makefile.
If you know Perl, you are not constrained at all by the set of makepp's builtin
textual manipulation functions.

You can also simply write Perl code in your makefile. You can manipulate Make
variables with the full power of the entire Perl language. See makepp_variables for
details.

Logging of build decisions
By default, makepp makes a log-file viewable with makepplog, mppl that contains a
description of every file that it tried to build, what rule was used to build it, what
it depended on, and (if the file was rebuilt) why. This can be extremely useful for
debugging a makefile--if you're wondering why makepp decided to rebuild a file, or why
it didn't, you can just look in the log file where it explains the decisions.

Improved support for parallel builds
Makepp supports parallel compilations, but (unlike other make implementations) it
won't mix output from separate processes which are running simultaneously.

Synonyms for cryptic variables
Makepp supports easier-to-remember synonyms for the cryptic make variables $@, $^, and
$<. See makepp_variables for details.

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