Simple Make

This is a demonstration of how to use llbuild to construct a simple build system that compiles all of the source files in a directory into one executable.

All of the examples use a simple framework simplebuild on top of llbuild that uses JSON-encoded representations for all of the keys and values, supports asynchronous execution, and that automatically dispatches to an appropriate Rule based on information encoded in the key. It also collapses the distinction between Rules and Tasks for simplicity. llbuild is currently designed with the expectation that most clients will have some similar kind of framework.

Installing

To run these examples, you will need:

1. A built copy of llbuild.dylib in ${LLBUILD}/build/lib/libllbuild.dylib (the default location if you use a CMake/Ninja build in a build subdirectory of the project).

2. The cffi Python module available.

3. The llbuild Python module available.

The easiest way to accomplish this is with::

# Configure and build llbuild in the expected location.
cd path/to/llbuild
mkdir -p build
cd build
cmake -G Ninja ..
ninja

# Install virtualenv, if not present.
sudo easy_install virtualenv

# Create a virtualenv and install ``cffi`` into it.
#
# We set CFLAGS to work around CFFI not properly getting the right include
# paths if there is no root SDK.
cd path/to/llbuild/examples/simple-make
virtualenv venv
env CFLAGS="-I$(xcrun --show-sdk-path)/usr/include/ffi" venv/bin/pip install cffi
source venv/bin/activate

# Ensure Python can find the ``llbuild`` module.
export PYTHONPATH=path/to/llbuild/bindings/python

Examples

The specific examples are:

1. count-lines-1 <FILE_PATH>

   This is a minimal demonstration of the simplebuild framework that counts the number of lines of an input file path.

2. count-lines-2 <FILE_PATH>

   This is an extension of count-lines-1 that adds external-synchronization on the file system state of the input, so that we can persist the count in a database.

3. count-lines-3 <DIR_PATH>

   This is an extension of count-lines-2 that shows how to count the lines for all files in a directory with appropriate dependencies so that the count is recomputed when the directory or the files change.

4. count-lines-4 <DIR_PATH>

   This is an extension of count-lines-3 that shows how we would deal with counting the lines using an external tool.

5. simple-make <DIR_PATH>

   This is an extension of the above examples to build all of the source files in a directory into an executable. It handles automatically rebuilding when the source files or the directory change. It does not currently attempt to handle other details (like header dependencies of the source files, or making sure that the output files are synchronized correctly).