WIP Build system overview (community made)

This page is made by someone who is not the developer and should not be considered as an official documentation of the build system. For getting the full picture, it is best to read the Makefiles and understand them yourself.

Makefile dep graph

Makefile                                                        --  include makefile 
|                                                               ~~  call make on subfolder
|-----  Makefile.system 
|       |
|       |=====  Makefile.prebuild # This is triggered (not included) by Makefile.system 
|       |                         # and runs before any of the code is built.
|       |
|       |-----  Makefile.rule
|       |
|       |-----  (Makefile.conf) [ generated - Makefile.system#L243 ]
|       |
|       |-----  (Makefile_kernel.conf) [ generated ]
|       |
|       |-----  Makefile.$(ARCH)
|
|~~~~~ exports/
|
|~~~~~ test/
|
|~~~~~ utest/
|
|~~~~~ ctest/
|
|~~~~~ cpp_thread_test/
|
|~~~~~ kernel/
|
|~~~~~ ${SUBDIRS}
|
|~~~~~ ${BLASDORS}
|
|~~~~~ ${NETLIB_LAPACK_DIR}{,/timing,/testing/{EIG,LIN}}
|
|~~~~~ relapack/

Important Variables

Most of the tunable variables are found in Makefile.rule, along with their detailed descriptions.
Most of the variables are detected automatically in Makefile.prebuild, if they are not set in the environment.

CPU related

ARCH -         Target architecture (eg. x86_64)
TARGET -       Target CPU architecture (to get better tuning, eg. haswell)
TARGET_CORE -  override TARGET (¿¿why do we need this??)
DYNAMIC_ARCH - For building library for multiple ARCHs (may lose some optimizations)

Toolchain related

CC -                 TARGET C compiler used for compilation (can be cross-toolchains)
FC -                 TARGET Fortran compiler used for compilation (can be cross-toolchains)
AR, AS, LD, RANLIB - TARGET toolchain helpers used for compilation (can be cross-toolchains)

HOSTCC -             compiler of build machine, needed to create proper config files for target architecture
HOST_CFLAGS -        flags for build machine compiler

Library related

BINARY          - 32/64 bit library

BUILD_SHARED    - Create shared library
BUILD_STATIC    - Create static library

QUAD_PRECISION  - Support for IEEE quad precision [ Experimental, don't use in production ]
EXPRECISION     - 
INT

BUILD_SINGLE    - ??
BUILD_DOUBLE    - ??
BUILD_COMPLEX   - ??
BUILD_COMPLEX16 - ??
USE_THREAD      - Use a threading backend (default to pthread)
USE_OPENMP      - Use OpenMP threading backend