Saturday, March 25, 2017

Today, I released build, a simple makefile-based build system derived from the makefiles for XL or ELFE.

Features

Build is a simple build system destined to make it easy to build C or

C++ programs without having to write lengthy makefiles or going through the complexity of tools such as automake or cmake. It is well suited for relatively small programs, although it has been used for at least one much larger program.

• Compact size (about 500 lines of active makefile code for a typical build)
• Fast, since short makefiles with few rules are quickly parsed
• Automatic generation of header-file dependencies
• Automatic logging of detailed build commands in log files
• Compact, colorized progress report
• Summary of errors and warnings at end of build
• Colorization of error and warning messages
• Rules to build various targets (optimized, debug, release, profile)
• Rule modifiers for common build options, e.g. v-debug for verbose debug
• Personal preferences easily defined with environment variables
• Built-in help (make help)
• Pure make, allowing you to use standard Makefile syntax and features
• Supports parallel builds
• Supports separate libraries with accelerated build

Using build

To use build, you create a Makefile. A minimal makefile only needs

to specify the name of the SOURCES, the name of the build PRODUCTS, and include the rules.mk file, which contains the makefile rules:

BUILD=build/
SOURCES=my-super-tool.cpp helper.c
PRODUCTS=my-super-tool.exe
include $(BUILD)rules.mk

That's all you need to get started. There is a small sample Makefile

in this distribution.

Note that the BUILD variable requires a trailing /. This is a

general convention in build for variables that denote directories (Rationale: You can leave these variables empty for the current directory).

For consistency across projects, it is recommended to leave build

in the build subdirectory. You can typically add build as a submodule in your project using:

git submodule add https://github.com/c3d/build.git

In order to get a summary of the available build targets, use make help.

Building the products

If you simply type make, a default build is launched. This is what

you should see if you do that in the build directory itself:

build> make
[BEGIN]              opt macosx-clang in [top]/build
[DEPEND]             hello.cpp
[BEGIN]              opt macosx-clang in [top]/build
[COMPILE  1/1]       hello.cpp
[BUILD]              hello
0 Errors, 0 Warnings in ./logs/build-macosx-clang-opt-20170325-144013.log

real    0m3.263s
user    0m0.456s
sys     0m0.133s

The output of the build will be located by default in build/objects.

There are subdirectories corresponding to the build environment and the build target, so the final product could be for instance under build/objects/macosx-clang/opt/hello. This is explained below.

The log files will be located by default in build/logs, the latest

one being called make.log.

You can clean the build products with make clean and force a clean

build with make rebuild.

Testing the products

Use make test to test the product. The simplest possible test is to

simply run the generated program. You can do this by adding a TESTS variable to your Makefile:

BUILD=build/
SOURCES=hello.cpp
PRODUCTS=hello.exe
TESTS=product
include $(BUILD)rules.mk

If you run make test (or make check) on the sample makefile found in the

distribution directory, you will run the hello program, after building it if necessary:

 build> make test
 [BEGIN]              opt macosx-clang in [top]/build
 [COMPILE  1/1]       hello.cpp
 [BUILD]              hello
 [TEST]               product
 You successfully built using build
 Output has 35 characters, should be 35

As you can see in the sample Makefile, it is easy to add tests,

simply by adding a rule that ends in .runtest. In the sample file, it is called count-characters.runtest.

Building for debugging, release or profiling

The default build is an optimized build similar to what you would

achieve by running make opt. It is well optimized, but still retains some debugging capabilities.

If you need more debugging capabilities, you can create a debug build

by using make debug. This disables most optimizations, making it easier for the debugger to relate machine code to source code.

If you want to remove all debugging symbols, you can generate a

release build by using make release.

Finally, you can build for profiling using make profile and

benchmark the result using make benchmark. This is still only partially tested and supported.

This list is likely to evolve over time, most notably with support for

Valgrind and other debug / analysis tools.

Installing the product

To install the product, use make install. This often requires

super-user privileges.

build> make install
[INSTALL]            opt macosx-clang in [top]/build
[INSTALL]            hello in /usr/local/bin

Build modifiers

Several built target modifiers can be used to modify the meaning of a

following target. For example, the v- prefix disables output filtering, so that you can see the complete build commands:

 build> make v-debug
 [...]
 [BEGIN]              debug macosx-clang in [top]/build
 g++ -std=gnu++0x                             -DCONFIG_MACOSX -DDEBUG   -g -Wall -fno-inline           -c hello.cpp -o objects/macosx-clang/debug/build/hello.cpp.o
 g++ -o objects/macosx-clang/debug/hello ./objects/macosx-clang/debug/build/hello.cpp.o   -framework CoreFoundation -framework CoreServices  -g
 [END]                debug macosx-clang in [top]/build

Note that this is not normally necessary, since the build commands are

preserved automatically in the build log every time you use make.

The build targets can be used also as build modifiers. For example, if

you do make clean, you only clean opt objects since this is the default target. If you want to clean debug objects, use make debug-clean. Similarly, you can do a release install with make release-install.

(Note that you can make debug your default target, see below).

Environment variables

Several environment variables control the behavior of build. The

variables that can be configured are found at the beginning of config.mk. Some of the most useful include:

• BUILDENV specifies the build environment, for example macosx-clang when building on MacOSX with Clang. Parameters for

  this build environment are defined in config.$(BUILDENV).mk, for example config.macosx-clang.mk. If not set, heuristics defined in config.auto.mk are used to try and determine the correct BUILDENV.

• TARGET specifies the default build target, which can be opt, debug, release or profile at the moment. If you often build debug targets, you only need to export BUILDENV=debug, and the default make will become equivalent to make debug.

• PREFIX specifies the installation location. You can also specify the installation location for executables (PREFIX_BIN), libraries (PREFIX_LIB) or shared libraries (PREFIX_DLL).

Hierarchical projects

Often, a project is made of several directories or libraries. In build, this is supported with two makefile variables:

• SUBDIRS lists subdirectories of the top-level directory that

  must be built every time.

• LIBRARIES lists libraries, which can be subdirectories or not, which the products depends on.

Subdirectories are re-built everytime a top-level build is started,

whereas libraries are re-built only if they are missing. It is possible to force a re-build of libraries using the d- or deep- prefix for builds, for example make deep-debug.