Build System for Native Client SDK examples

The examples and libraries that ship with the Native Client SDK use a build system based on GNU Make.

Each example or library is contained in its own directory along with a Makefile. The Makefiles are capable of building Native Client applications and libraries using any of the available toolchains as well as building host applications with the host's toolchain. In order to keep the top-level Makefiles simple, most of actual build rules are specified in as set of shared rules files in the $NACL_SDK_ROOT/tools directory.

This document describes some of the variables and macros used by in the build system. For more details please see the .mk files in the tools folder.

Using the build system for new projects

It is perfectly possible to use the included build system for projects outside of the Native Client SDK. A good starting point for doing this would be to copy the Makefile from the hello_world example. In most simple cases the only changes needed are to update the SOURCES and TARGET variables.

User Variables

TARGET

This variable holds the name of your project. Normally this is the basename of the library or executable which is the final target.

SOURCES

The list of sources to be built. In most cases this list is passed to the compile and link macros.

VALID_TOOLCHAINS

This variable can be used to control which toolchains are supported by the project. Valid entries for this list are: newlib, glibc, pnacl, linux, mac, win. The default value is: "newlib glibc pnacl".

NACL_SDK_ROOT

Optionally force the build system to use a certain location for the Native Client SDK. If not set within the Makefile the $NACL_SDK_ROOT environment variable will by used. It is an error if this variable is neither set within the Makefile nor in the environment.

Macros / Rules

The following macros can be used in the Makefiles to generate the rules for building the various kinds types of target. These are designed to be used via the 'call' macro. e.g. $(call COMPILE_RULE,$(SOURCES))

COMPILE_RULE

This rule is used to build object files from a list of sources.

SO_RULE

Used to build shared objects from a list of sources.

LIB_RULE

Used to build static libraries from a list of sources.

NMF_RULE

Used to build nmf metadata file from a native client executable (or set of executables). This is needed in order to run the executable in chrome.

HTML_RULE

Used to build both html and nmf files from a native client executable (or set of executables) which will allow the executable to be run in chrome.

For more information on how to use these rules in your Makefile see the shared Makefiles in the tools folders:

common.mk

Top level shared rules file that include the toolchain specific rules.

nacl_gcc.mk

Rules for building using the gcc-based NaCl toolchains.

nacl_llvm.mk

Rules for building using the llvm-based PNaCl toolchains.

host_gcc.mk

Rules for building using the linux/mac host gcc toolchain.

host_vc.mk

Rules for building using the windows Visual Studio toolchain.