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                                                        
|                                                               
|-----  Makefile.system 
|       |
|       |=====  Makefile.prebuild # This is triggered (not included) by Makefile.system 
|       |       |                 # and runs before any of the code is built.
|       |       |
|       |       -----  (Makefile.conf) [ either this or Makefile_kernel.conf is generated ] 
|       |       |                            { Makefile.system#L243 }
|       |       -----  (Makefile_kernel.conf) [ either this or Makefile.conf is generated ]
|       |
|       |-----  Makefile.rule
|       |
|       |-----  Makefile.$(ARCH)
|
|~~~~~ exports/
|
|~~~~~ test/
|
|~~~~~ utest/
|
|~~~~~ ctest/
|
|~~~~~ cpp_thread_test/
|
|~~~~~ kernel/
|
|~~~~~ ${SUBDIRS}
|
|~~~~~ ${BLASDIRS}
|
|~~~~~ ${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, for use in DYNAMIC_ARCH=1 (to get better tuning, eg. haswell)
TARGET_CORE  - TARGET_CORE will override TARGET
DYNAMIC_ARCH - For building library for multiple ARCHs (does not lose any optimizations, but increases library size)

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 and largely unimplemented, don't use in production ]
EXPRECISION     - 
INTERFACE64     - Build with 64bit integer representations [ incompatible with standard API ]

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