CMake Build System Overview

[TOC]

This document provides a general layout of the Draco CMake build system.

Core Build System Files

These files are listed in order of interest to maintainers of the build system.

• CMakeLists.txt is the main driver of the build system. It's responsible for defining targets and source lists, surfacing build system options, and tying the components of the build system together.

• cmake/draco_build_definitions.cmake defines the macro draco_set_build_definitions(), which is called from CMakeLists.txt to configure include paths, compiler and linker flags, library settings, platform speficic configuration, and other build system settings that depend on optional build configurations.

• cmake/draco_targets.cmake defines the macros draco_add_library() and draco_add_executable() which are used to create all targets in the CMake build. These macros attempt to behave in a manner that loosely mirrors the blaze cc_library() and cc_binary() commands. Note that draco_add_executable() is also used for tests.

• cmake/draco_emscripten.cmake handles Emscripten SDK integration. It defines several Emscripten specific macros that are required to build the Emscripten specific targets defined in CMakeLists.txt.

• cmake/draco_flags.cmake defines macros related to compiler and linker flags. Testing macros, macros for isolating flags to specific source files, and the main flag configuration function for the library are defined here.

• cmake/draco_options.cmake defines macros that control optional features of draco, and help track draco library and build system options.

• cmake/draco_install.cmake defines the draco install target.

• cmake/draco_cpu_detection.cmake determines the optimization types to enable based on target system processor as reported by CMake.

• cmake/draco_intrinsics.cmake manages flags for source files that use intrinsics. It handles detection of whether flags are necessary, and the application of the flags to the sources that need them when they are required.

Helper and Utility Files

• .cmake-format.py Defines coding style for cmake-format.

• cmake/draco_helpers.cmake defines utility macros.

• cmake/draco_sanitizer.cmake defines the draco_configure_sanitizer() macro, which implements support for DRACO_SANITIZE. It handles the compiler and linker flags necessary for using sanitizers like asan and msan.

• cmake/draco_variables.cmake defines macros for tracking and control of draco build system variables.

Toolchain Files

These files help facilitate cross compiling of draco for various targets.

• cmake/toolchains/aarch64-linux-gnu.cmake provides cross compilation support for arm64 targets.

• cmake/toolchains/android.cmake provides cross compilation support for Android targets.

• cmake/toolchains/arm-linux-gnueabihf.cmake provides cross compilation support for armv7 targets.

• cmake/toolchains/arm64-ios.cmake, cmake/toolchains/armv7-ios.cmake, and cmake/toolchains/armv7s-ios.cmake provide support for iOS.

• cmake/toolchains/arm64-linux-gcc.cmake and cmake/toolchains/armv7-linux-gcc.cmake are deprecated, but remain for compatibility. cmake/toolchains/android.cmake should be used instead.

• cmake/toolchains/arm64-android-ndk-libcpp.cmake, cmake/toolchains/armv7-android-ndk-libcpp.cmake, cmake/toolchains/x86-android-ndk-libcpp.cmake, and cmake/toolchains/x86_64-android-ndk-libcpp.cmake are deprecated, but remain for compatibility. cmake/toolchains/android.cmake should be used instead.

• cmake/toolchains/i386-ios.cmake and cmake/toolchains/x86_64-ios.cmake provide support for the iOS simulator.

• cmake/toolchains/android-ndk-common.cmake and cmake/toolchains/arm-ios-common.cmake are support files used by other toolchain files.

Template Files

These files are inputs to the CMake build and are used to generate inputs to the build system output by CMake.

• cmake/draco-config.cmake.template is used to produce draco-config.cmake. draco-config.cmake can be used by CMake to find draco when another CMake project depends on draco.

• cmake/draco.pc.template is used to produce draco's pkg-config file. Some build systems use pkg-config to configure include and library paths when they depend upon third party libraries like draco.