# Makefile.pdlibbuilder version 0.0.0, dated 2015-06-25
#
# Helper makefile for Pure Data external libraries.
# Written by Katja Vetter March-June 2015 for the public domain. No warranties.
# Inspired by Hans Christoph Steiner's Makefile Template and Stephan Beal's
# ShakeNMake.
#
# GNU make version >= 3.81 required.
#
#
#=== characteristics ===========================================================
#
#
# - defines build settings based on autodetected OS and architecture
# - defines rules to build Pd class- or lib executables from C or C++ sources
# - defines rules for libdir installation
# - defines convenience targets for developer and user
# - evaluates implicit dependencies for non-clean builds
#
#
#=== basic usage ===============================================================
#
#
# In your Makefile, define your Pd lib name and class files, and include
# Makefile.pdlibbuilder at the end of the Makefile. Like so:
#
#    ________________________________________________________________________
#
#     # Makefile for mylib
#
#     lib.name = mylib
#
#     class.sources = myclass1.c myclass2.c
#
#     datafiles = myclass1-help.pd myclass2-help.pd README.txt LICENSE.txt
#
#     include Makefile.pdlibbuilder
#    ________________________________________________________________________
#
#
# For files in class.sources it is assumed that class basename == source file
# basename. The default target builds all classes as individual executables
# with Pd's default extension for the platform. For anything more than the
# most basic usage, continue reading.
#
#
#=== list of Makefile.pdlibbuilder API variables ===============================
#
#
# Variables available for definition in your library Makefile:
#
# - lib.name
# - lib.setup.sources
# - class.sources
# - common.sources
# - shared.sources
# - <classname>.class.sources
# - <classname>.class.ldflags
# - <classname>.class.ldlibs
# - cflags
# - ldflags
# - ldlibs
# - datafiles
# - datadirs
# - makefiles
# - makefiledirs
# - externalsdir
#
# Variables avaialable for (re)definition via command arguments:
#
# - pdbinpath (Windows only)
# - pdincludepath
# - DESTDIR
# - prefix
# - libdir
# - pkglibdir
# - CFLAGS
# - CC
# - CXX
# - INSTALL
# - INSTALL_PROGRAM
# - INSTALL_DATA
# - INSTALL_DIR
#
# Variables available for your makefile or as command argument:
#
# - objectsdir
# - make-lib-executable
# - suppress-wunused
#
#
#=== descriptions of Makefile.pdlibbuilder API variables =======================
#
#
# lib.name: 
# Name of the library directory as it will be installed / distributed. Also the
# name of the lib executable in the case where all classes are linked into
# a single binary.
#
# lib.setup.sources:
# Source file(s) (C or C++) which must be compiled only when linking all classes
# into a single lib binary.
#
# class.sources:
# All sources files (C or C++) for which the condition holds that 
# class name == source file basename.
#
# <classname>.class.sources:
# Source file(s) (C or C++) specific to class <classname>. Use this for
# multiple-source classes or when class name != source file basename.
#
# common.sources:
# Source file(s) which must be statically linked to each class in the library.
#
# shared.sources:
# Source file(s) (C or C++) to build a shared dynamic link lib, to be linked
# with all class executables.
#
# cflags, ldflags, ldlibs:
# Define cflags (preprocessor&compiler), ldflags (linker) and ldlibs (dynamic
# link libs) for the whole library. These flags are added to platform-specific
# flags defined by Makefile.pdlibbuilder.
#
# <classname>.class.ldflags and <classname>.class.ldlibs: 
# Define ldflags resp. ldlibs specific to class <classname>. These flags are
# added to platform-specific flags defined by Makefile.pdlibbuilder, and flags
# defined in your Makefile for the whole library. Note: cflags can not be
# defined per class in the current implementation.
#
# datafiles and datadirs: 
# All extra files you want to include in binary distributions of the
# library: abstractions and help patches, example patches, meta patch, readme
# and license texts, manuals, sound files, etcetera. Use 'datafiles' for all
# files that should go into your lib rootdir and 'datadirs' for complete
# directories you want to copy from source to distribution.
#
# externalsdir: 
# Relative path to directory 'externals' in the context of pd-extended SVN, or
# any other centralized build layout for multiple libraries. Default value
# is '..', meaning the direct parent. The value is used in search paths for 
# pd core components (header files, and executable in the case of Windows).
#
# makefiles and makefiledirs: 
# Extra makefiles or directories with makefiles that should be made in sub-make
# processes.
#
# pdbinpath:
# For Windows only. Directory where pd.dll can be found for linking.
#
# pdincludepath:
# Directory where Pd API m_pd.h can be found, and other Pd header files.
#
# DESTDIR, prefix, libdir:
# Components of the path for installation as conventionally used on Linux.
#
# pkglibdir:
# Base path for installation of Pd library directories. Default is specified
# per OS, see section about paths below.
#
# objectsdir:
# Alias of pkglibdir. Can be defined in your makefile to enable project-
# dependent relative install locations.
#
# CFLAGS:
# Compiler (notably optimization) flags which are defined by 
# Makefile.pdlibbuilder, but may be overriden via command argument.
#
# CC and CXX:
# C and C++ compiler programs as defined in your build environment.
#
# INSTALL, INSTALL_PROGRAM, INSTALL_DATA, INSTALL_DIR:
# Definitions of install program, may be overriden via command argument.
#
# make-lib-executable:
# When this variable is defined 'yes' in your makefile or as command argument,
# Makefile.pdlibbuilder will try to build all classes into a single library
# executable (but it will force exit if lib.setup.sources is undefined).
# If your makefile defines 'make-lib-executable=yes' as the library default,
# this can still be overriden with 'make-lib-executable=no' as command argument 
# to build individual class executables (the Makefile.pdlibbuilder default.)
#
# suppress-wunused:
# When this variable is defined ('yes' or any other value), -Wunused-variable,
# -Wunused-parameter, -Wunused-value and -Wunused-function are suppressed,
# but the other warnings from -Wall are retained.
#
#
#=== paths =====================================================================
#
#
# Source files in directories other than current working directory must be
# prefixed with their relative path. Do not rely on VPATH or vpath.
# Object (.o) files are built in the directory of their source files.
# Executables are built in current working directory. 
#
# Variable 'pdincludepath' stores the location where m_pd.h was found.
# Locations where Makefile.pdlibbuilder tries to find it, in order of priority:
#
# any OS:   $(externalsdir)../pd/src/
#
# Linux:    /usr/include/pdextended/
#           /usr/include/pd/
#
# OSX:      /Applications/Pd-extended.app/Contents/Resources/include/pdextended/
#           /Applications/Pd.app/Contents/Resources/src/
#
# Windows:  %PROGRAMFILES%/pd/include/pdextended/
#           %PROGRAMFILES%/pd/src/
#
# The path for installation of all library components is constructed as:
#
# installpath := $(DESTDIR)$(objectsdir)/$(lib.name)
#
# Default for 'objectsdir' is defined per platform and follows this convention:
# https://puredata.info/docs/faq/how-do-i-install-externals-and-help-files
#
# Linux:    /usr/local/lib/pd-externals
# OSX:      ~/Library/Pd
# Windows:  %APPDATA%/Pd
#
# The rationale for not installing to ~/pd-externals by default on Linux
# is that some people share the home dir between 32 and 64 bit installations.
#
#
#=== targets ===================================================================
#
#
# all: build classes (default) or library blob (if make-lib-executable=true)
# alldebug: build all with -g option turned on for debug symbols
# <classname>: force clean build of an individual class
# <sourcefile>.pre: make preprocessor output file in current working directory
# <sourcefile>.lst: make asm/source output file in current working directory
#
# install: install executables and data files
# clean: remove build products from source tree
#
# help: print help text
# vars: print makefile variables
# allvars: print all variables
# depend: print generated prerequisites
# coffee: dummy target
#
#
#=== Pd-extended libdir concept ================================================
#
#
# For libdir layout as conceived by Hans-Christoph Steiner, see:
#
# https://puredata.info/docs/developer/Libdir
#
# Files README.txt, LICENSE.txt and <lib.name>-meta.pd are part of the libdir
# convention. Help patches for each class and abstraction are supposed to be
# available. Makefile.pdlibbuilder does not force the presence of these files
# however. It does not automatically include such files in libdir installations.
# Data files you want to include in distributions must be defined explicitly in
# your Makefile.
#
#
#=== Makefile.pdlibbuilder syntax conventions ==================================
#
#
# Makefile.pdlibbuilder variable names are lower case. Default make variables,
# environment variables, and standard user variables (CC, CXX, CFLAGS, DESTDIR)
# are upper case. Use target 'allvars' to print all variables and their values.
#
# 'Fields' in data variables are separated by dots, like in 'foo.class.sources'.
# Words in variables expressing a function or command are separated by dashes, 
# like in 'make-lib-executable'.
#
#
#=== useful make options =======================================================
#
#
# Use 'make -d <target>' to print debug details of the make process.
# Use 'make -p <target>' to print make's database.
#
#
#=== TODO ======================================================================
#
#
# - decide whether to use -static-libgcc or shared dll in MinGW
# - cygwin support
# - android support
# - Windows 64 bit support
# - figure out how to handle '$' in filenames
# - add makefile template targets dpkg-source dist libdir distclean tags?
#
#
#=== end of documentation sections =============================================
#
# 
################################################################################
################################################################################
################################################################################


# GNU make version 3.81 (2006) or higher is required because of the following:
# - function 'info'
# - variable '.DEFAULT_GOAL'

# force exit when make version is < 3.81
ifneq ($(firstword $(sort 3.81 $(MAKE_VERSION))), 3.81)
  $(error GNU make version 3.81 or higher is required)
endif

# Relative path to externals root dir in multi-lib source tree like 
# pd-extended SVN. Default is parent of current working directory. May be
# defined differently in including makefile. This variable is used to probe for
# paths.
externalsdir ?= ..

# variable you can use to check if Makefile.pdlibbuilder is already included
Makefile.pdlibbuilder = true


################################################################################
### variables: files ###########################################################
################################################################################


# strip possibles spaces from lib.name, they mess up calculated file names
lib.name := $(strip $(lib.name))


#=== sources ===================================================================


# (re)define <classname>.class.sources using file names in class.sources

define add-class-source
$(notdir $(basename $v)).class.sources += $v
endef

$(foreach v, $(class.sources), $(eval $(add-class-source)))

# derive class names from <classname>.class.sources variables
sourcevariables := $(filter %.class.sources, $(.VARIABLES))
classes := $(basename $(basename $(sourcevariables)))

# accumulate all source files specified in makefile
classes.sources := $(sort $(foreach v, $(sourcevariables), $($v)))
all.sources := $(classes.sources) $(lib.setup.sources) \
  $(shared.sources) $(common.sources)


#=== object files ==============================================================


# construct object filenames from all C and C++ source file names
classes.objects := $(addsuffix .o, $(basename $(classes.sources)))
common.objects := $(addsuffix .o, $(basename $(common.sources)))
shared.objects := $(addsuffix .o, $(basename $(shared.sources)))
lib.setup.objects := $(addsuffix .o, $(basename $(lib.setup.sources)))
all.objects = $(classes.objects) $(common.objects) $(shared.objects) \
  $(lib.setup.objects)


#=== executables ===============================================================


# use recursive variables here because executable extension is not yet known

# construct class executable names from class names
classes.executables = $(addsuffix .$(extension), $(classes))

# construct shared lib executable name if shared sources are defined
ifdef shared.sources
  shared.lib = lib$(lib.name).$(shared.extension)
else
  shared.lib =
endif


################################################################################
### variables per platform #####################################################
################################################################################


#=== flags per architecture ====================================================


# Set architecture-dependent flags, mainly for Linux. For Mac and Windows, 
# arch.flags are overriden below.

machine := $(shell uname -m)

# Raspberry Pi 1st generation
ifeq ($(machine), armv6l)
  arch.flags = -march=armv6 -mfpu=vfp -mfloat-abi=hard
endif

# Beagle, Udoo, RPi2 etc.
ifeq ($(machine), armv7l)
  arch.flags = -march=armv7-a -mfpu=vfpv3 -mfloat-abi=hard
endif

# Intel 32 bit, build with SSE and SSE2 instructions
ifeq ($(findstring $(machine), i386 i686), $(machine))
  arch.flags = -march=pentium4 -mfpmath=sse -msse -msse2
endif

# Intel/AMD 64 bit, build with SSE, SSE2 and SSE3 instructions
ifeq ($(findstring $(machine), ia64 x86_64), $(machine))
  arch.flags = -march=core2 -mfpmath=sse -msse -msse2 -msse3 
endif


#=== operating system ==========================================================


# The following systems are defined: Linux, Darwin, Windows. GNU and
# GNU/kFreeBSD are treated as Linux to get the same options. 

uname := $(shell uname)

ifeq ($(findstring $(uname), Linux GNU GNU/kFreeBSD), $(uname))
  system = Linux
endif

ifeq ($(uname), Darwin)
  system = Darwin
endif

ifeq ($(findstring MINGW, $(uname)), MINGW)
  system = Windows
endif

# TODO: Cygwin, Android


#=== flags and paths for Linux =================================================


ifeq ($(system), Linux)
  prefix = /usr/local
  libdir := $(prefix)/lib
  pkglibdir = $(libdir)/pd-externals
  pdincludepath := $(firstword $(dir $(wildcard \
    $(externalsdir)/../pd/src/m_pd.h \
    /usr/include/pdextended/m_pd.h \
    /usr/include/pd/m_pd.h)))
  extension = pd_linux
  cpp.flags := -DUNIX
  c.flags := -fpic
  c.ldflags := -rdynamic -shared -fpic -Wl,-rpath,"\$$ORIGIN",--enable-new-dtags
  c.ldlibs := -lc -lm
  cxx.flags := -fpic -fcheck-new
  cxx.ldflags := -rdynamic -shared -fpic -Wl,-rpath,"\$$ORIGIN",--enable-new-dtags
  cxx.ldlibs := -lc -lm -lstdc++
  shared.extension = so
  shared.ldflags := -rdynamic -fpic -shared -Wl,-soname,$(shared.lib)
  stripflags = --strip-unneeded -R .note -R .comment
endif


#=== flags and paths for Darwin ================================================


# On OSX we try to build fat binaries by default. It is assumed that OSX i386
# can build for ppc and OSX x86_64 can't. TODO: try to refine this condition.
# LLVM-clang doesn't support -fcheck-new, therefore this flag is omitted for
# OSX x86_64.

ifeq ($(system), Darwin)
  pkglibdir = $(HOME)/Library/Pd
  pdincludepath := $(firstword $(dir $(wildcard \
    $(externalsdir)/../pd/src/m_pd.h \
    /Applications/Pd-extended.app/Contents/Resources/include/pdextended/m_pd.h \
    /Applications/Pd.app/Contents/Resources/src/m_pd.h)))
  extension = pd_darwin
  arch.flags =
  cpp.flags := -DUNIX -DMACOSX -I /sw/include
  c.flags := 
  c.ldflags := -undefined suppress -flat_namespace -bundle
  c.ldlibs := -lc
  cxx.ldflags := -undefined suppress -flat_namespace -bundle
  cxx.ldlibs := -lc
  shared.extension = dylib
  shared.ldflags = -dynamiclib -undefined dynamic_lookup \
    -install_name @loader_path/$(shared.lib) \
    -compatibility_version 1 -current_version 1.0
  stripflags = -x
  ifeq ($(machine), i386)
    cxx.flags := -fcheck-new
    arch.flags := -arch ppc -arch i386 -arch x86_64 -mmacosx-version-min=10.4
  endif
  ifeq ($(machine), x86_64)
    arch.flags := -arch i386 -arch x86_64 -mmacosx-version-min=10.5
  endif
endif


#=== flags and paths for Windows ===============================================


# Standard paths on Windows contain spaces, and GNU make functions treat such
# paths as lists, with unintended effects. Therefore we must use shell function
# ls instead of make's wildcard, and probe for each standard path individually.
# Using double quotes around paths with spaces is obligatory. Since some path
# variables are assembled or re-expanded later, great care must be taken to put
# quotes at appropriate points throughout the makefile. Thanks, Bill.

# paths for 32-bit executables on 64-bit Windows aren't yet defined here (TODO)
ifeq ($(system), Windows)
  pkglibdir := $(APPDATA)/Pd
  pdbinpath := $(wildcard $(externalsdir)/../pd/bin/)
  pdincludepath := $(wildcard $(externalsdir)/../pd/src/)
  ifndef pdbinpath
    pdbinpath := $(shell ls -d "$(PROGRAMFILES)/pd/bin/")
  endif
  ifndef pdincludepath
    pdincludepath := $(shell ls -d "$(PROGRAMFILES)/pd/include/pdextended/")
  endif
  ifndef pdincludepath
    pdincludepath := $(shell ls -d "$(PROGRAMFILES)/pd/src/")
  endif
endif

# On Windows we build 32 bit by default to match Pd(-extended) binary 
# distributions. This may change in the future.
# TODO: decide whether -mms-bitfields should be specified.
ifeq ($(system), Windows)
  extension = dll
  CC = gcc
  CXX = g++
  arch.flags := -march=pentium4 -msse -msse2 -mfpmath=sse
  cpp.flags := -DMSW -DNT
  c.flags :=
  c.ldflags := -static-libgcc -shared \
    -Wl,--enable-auto-import "$(pdbinpath)pd.dll"
  c.ldlibs :=
  cxx.flags := -fcheck-new
  cxx.ldflags := -static-libstdc++ -shared \
    -Wl,--enable-auto-import "$(pdbinpath)pd.dll"
  cxx.ldlibs :=
  shared.extension = dll
  shared.ldflags := -static-libgcc -shared "$(pdbinpath)pd.dll"
  stripflags = --strip-unneeded -R .note -R .comment
endif


#=== paths =====================================================================


# Default pkglibdir is specified above per operating system. It is aliased as 
# 'objectsdir' to retain compatibility with pd-extended template. Assignment
# operator '?=' is used to enable a project-relative path definition in the
# including makefile.
objectsdir ?= $(pkglibdir)

# base path where all components of the lib will be installed by default
installpath := $(DESTDIR)$(objectsdir)/$(lib.name)

# check if pdincludepath contains spaces (as is often the case on Windows)
# if so, store the path so we can later do checks with it
pdincludepathwithspaces := $(if $(word 2, $(pdincludepath)), $(pdincludepath))


#=== accumulated build flags ===================================================


# From GNU make docs: 'Users expect to be able to specify CFLAGS freely
# themselves.' So we use CFLAGS to define platform-independent options which 
# are not strictly required for compilation: optimizations and warnings. CFLAGS
# can be safely overriden using a make command argument.
# Variables cflags, ldflags and ldlibs may be defined in including makefile.

optimization.flags = -O3 -ffast-math -funroll-loops -fomit-frame-pointer
warn.flags = -Wall -Wextra -Wshadow -Winline -Wstrict-aliasing

# suppress -Wunused-variable & Co if you don't want to clutter a build log
ifdef suppress-wunused
  warn.flags += $(addprefix -Wno-unused-, function parameter value variable)
endif

CFLAGS = $(warn.flags) $(optimization.flags)

# preprocessor flags
cpp.flags += -DPD -I "$(pdincludepath)"

# flags for C compiler / linker
c.flags := $(cpp.flags) $(c.flags) $(cflags) $(CFLAGS)
c.ldflags := $(c.ldflags) $(ldflags)
c.ldlibs := $(c.ldlibs) $(ldlibs)

# flags for C++ compiler / linker
cxx.flags := $(cpp.flags) $(cxx.flags) $(cflags) $(CFLAGS)
cxx.ldflags := $(cxx.ldflags) $(ldflags)
cxx.ldlibs := $(cxx.ldlibs) $(ldlibs)


################################################################################
### variables: tools ###########################################################
################################################################################


# aliases so we can later define 'compile-$1' and set 'c' or 'cxx' as argument
compile-c := $(CC)
compile-cxx := $(CXX)


################################################################################
### checks #####################################################################
################################################################################


# At this point most variables are defined. Now do some checks and info's
# before rules begin.

# 'forward declaration' of default target, needed to do checks
all:

# To avoid unpredictable results, make sure the default target is not redefined
# by including makefile. 
ifneq ($(.DEFAULT_GOAL), all)
  $(error Default target must be 'all'.)
endif

# find out which target(s) will be made
ifdef MAKECMDGOALS
  goals := $(MAKECMDGOALS)
else
  goals := all
endif

# check if m_pd.h is found and print info about it
$(if $(shell ls "$(pdincludepath)m_pd.h"), \
  $(info ++++ info: using Pd API $(pdincludepath)m_pd.h), \
  $(warning Where is your m_pd.h? Do 'make help' for info.))

# print target info
$(info ++++ info: making target $(goals) $(if $(lib.name),in lib $(lib.name)))

# when installing, print installpath info
$(if $(filter install install-lib, $(goals)), $(info ++++ info: \
  installpath is '$(installpath)'))


#=== define executables ========================================================


# By default we build class executables, and optionally a shared dynamic link
# lib. When make-lib-executable=yes we build all classes into a single lib
# executable, on the condition that variable lib.setup.sources is defined.

ifeq ($(make-lib-executable),yes)
  $(if $(lib.setup.sources), ,\
    $(error Can not build library blob because lib.setup.sources is undefined))
  executables := $(lib.name).$(extension)
else
  executables := $(classes.executables) $(shared.lib)
endif


#=== library version ===========================================================


# if meta file exists, check library version 

metafile := $(wildcard $(lib.name)-meta.pd)

ifdef metafile
  lib.version := $(shell sed -n \
    's|^\#X text [0-9][0-9]* [0-9][0-9]* VERSION \(.*\);|\1|p' \
    $(metafile))
endif


################################################################################
### rules: special targets #####################################################
################################################################################


# Disable built-in rules. If some target can't be built with the specified
# rules, it should not be built at all.
MAKEFLAGS += --no-builtin-rules

.PRECIOUS:
.SUFFIXES:
.PHONY: all build-classes build-lib $(classes) $(makefiledirs) $(makefiles)\
        install install-executables install-datafiles install-datadirs \
        force clean vars allvars depend help \
	pre post


################################################################################
### rules: build targets #######################################################
################################################################################


# target all builds class executables plus optional shared lib
# or alternatively a single lib executable when make-lib-executable=true
all: pre $(executables) post
	$(info ++++ info: $(if $(executables),executables in $(lib.name) completed))

pre post:

# build all with -g option turned on for debug symbols
alldebug: c.flags += -g
alldebug: cxx.flags += -g
alldebug: all


#=== class executable ==========================================================


# recipe for linking objects in class executable
# argument $1 = compiler type (c or cxx)
# argument $2 = class basename
define link-class
  $(compile-$1) \
  $(arch.flags) \
  $($1.ldflags) $($2.class.ldflags) \
  -o $2.$(extension) \
  $(addsuffix .o, $(basename $($2.class.sources))) \
  $(addsuffix .o, $(basename $(common.sources))) \
  $($1.ldlibs) $($2.class.ldlibs) $(shared.lib)
endef

# general rule for linking object files in class executable
%.$(extension): $(shared.lib)
	$(info ++++ info: linking objects in $@ for lib $(lib.name))
	$(if $(filter %.cc %.cpp, $($*.class.sources)), \
        $(call link-class,cxx,$*), \
        $(call link-class,c,$*))


#=== library blob ==============================================================


# build all classes into single executable
build-lib: $(lib.name).$(extension)
	$(info ++++ info: library blob $(lib.name).$(extension) completed)

# recipe for linking objects in lib executable
# argument $1 = compiler type (c or cxx)
define link-lib
  $(compile-$1) \
  $(arch.flags) \
  $($1.ldflags) $(lib.ldflags) \
  -o $(lib.name).$(extension) $(all.objects) \
  $($1.ldlibs) $(lib.ldlibs)
endef

# rule for linking objects in lib executable
# declared conditionally to avoid name clashes
ifeq ($(make-lib-executable),yes)
$(lib.name).$(extension): $(all.objects)
	$(if $(filter %.cc %.cpp, $(all.sources)), \
        $(call link-lib,cxx), \
        $(call link-lib,c))
endif


#=== shared dynamic lib ========================================================


# recipe for linking objects in shared executable
# argument $1 = compiler type (c or cxx)
define link-shared
  $(compile-$1) \
  $(arch.flags) \
  $(shared.ldflags) \
  -o lib$(lib.name).$(shared.extension) $(shared.objects) \
  $($1.ldlibs) $(shared.ldlibs)
endef

# rule for linking objects in shared executable
# build recipe is in macro 'link-shared'
lib$(lib.name).$(shared.extension): $(shared.objects)
	$(info ++++ info: linking objects in shared lib $@)
	$(if $(filter %.cc %.cpp, $(shared.sources)), \
        $(call link-shared,cxx), \
        $(call link-shared,c))


#=== object files ==============================================================


# recipe to make .o file from source
# argument $1 is compiler type (c or cxx)
define make-object-file
  $(info ++++ info: making $@ in lib $(lib.name))
  $(compile-$1) \
  $($1.flags) \
  $(arch.flags) -o $@ -c $<
endef

# Three rules to create .o files. These are double colon 'terminal' rules,
# meaning they are the last in a rules chain.

%.o:: %.c
	$(call make-object-file,c)

%.o:: %.cc
	$(call make-object-file,cxx)

%.o:: %.cpp
	$(call make-object-file,cxx)


#=== explicit prerequisites for class executables ==============================


# For class executables, prerequisite rules are declared in run time. Target
# 'depend' prints these rules for debugging purposes.

# declare explicit prerequisites rule like 'class: class.extension'
# argument $v is class basename
define declare-class-target
$v: $v.$(extension)
endef

# declare explicit prerequisites rule like 'class.extension: object1.o object2.o'
# argument $v is class basename
define declare-class-executable-target
$v.$(extension): $(addsuffix .o, $(basename $($v.class.sources))) \
  $(addsuffix .o, $(basename $(common.sources)))
endef

# evaluate explicit prerequisite rules for all classes
$(foreach v, $(classes), $(eval $(declare-class-target)))
$(foreach v, $(classes), $(eval $(declare-class-executable-target)))


#=== implicit prerequisites for class executables ==============================


# Evaluating implicit prerequisites (header files) with help from the
# preprocessor is 'expensive' so this is done conditionally and selectively.
# Note that it is also possible to trigger a build via install targets, in
# which case implicit prerequisites are not checked.

# When the Pd include path contains spaces it will mess up the implicit
# prerequisites rules so we do not evaluate them in that case.

ifndef pdincludepathwithspaces
  must-build-everything := $(filter all default lib, $(goals))
  must-build-class := $(filter $(classes), $(goals))
  must-build-sources := $(foreach v, $(must-build-class), $($v.class.sources))
endif

# declare implicit prerequisites rule like 'object.o: header1.h header2.h ...'
# argument $1 is input source file(s)
define declare-object-target
$(filter %.o: %.h, $(shell $(CPP) $(c.flags) -MM $1)) $(MAKEFILE_LIST)
endef

# evaluate implicit prerequisite rules when rebuilding everything
ifdef must-build-everything
  $(if $(wildcard $(all.objects)), \
  $(info ++++ info: evaluating implicit prerequisites in lib $(lib.name).....) \
  $(foreach v, $(all.sources), $(eval $(call declare-object-target, $v))))
endif

# evaluate implicit prerequisite rules when selectively building classes
ifdef must-build-class
  $(foreach v, $(must-build-sources), \
  $(eval $(call declare-object-target, $v)))
  $(foreach v, $(shared.sources), \
  $(eval $(call declare-object-target, $v)))
endif


################################################################################
### rules: preprocessor and assembly files #####################################
################################################################################


# Preprocessor and assembly output files for bug tracing etc. They are not part
# of the build processes for executables. By default these files are created in
# the current working directory. Dependency tracking is not performed, the build
# is forced instead to make sure it's up to date.

force:


#=== preprocessor file =========================================================


# make preprocessor output file with extension .pre
# argument $1 = compiler type (c or cxx)
define make-preprocessor-file
  $(info ++++ info: making preprocessor output file $(notdir $*.pre) \
  in current working directory)
  $(compile-$1) -E $< $(c.flags) $($1.flags) -o $(notdir $*.pre)
endef

%.pre:: %.c force
	$(call make-preprocessor-file,c)

%.pre:: %.cc force
	$(call make-preprocessor-file,cxx)

%.pre:: %.cpp force 
	$(call make-preprocessor-file,cxx)


#=== assembly file =============================================================


# make C / assembly interleaved output file with extension .lst
# argument $1 = compiler type (c or cxx)
define make-assembly-file
  $(info ++++ info: making assembly output file $(notdir $*.lst) \
  in current working directory)
  $(compile-$1) \
  -c -Wa,-a,-ad -fverbose-asm \
  $($1.flags) \
  $(arch.flags) \
  $< > $(notdir $*.lst)
endef

%.lst:: %.c force
	$(call make-assembly-file,c)

%.lst:: %.cc force
	$(call make-assembly-file,cxx)

%.lst:: %.cpp force
	$(call make-assembly-file,cxx)


################################################################################
### rules: installation targets ################################################
################################################################################


# Install targets depend on successful exit status of target all because nothing
# must be installed in case of a build error.


# -p = preserve time stamps
# -m = set permission mode (as in chmod)
# -d = create all components of specified directories
INSTALL = install
INSTALL_PROGRAM := $(INSTALL) -p -m 644
INSTALL_DATA := $(INSTALL) -p -m 644
INSTALL_DIR := $(INSTALL) -m 755 -d

# strip spaces from file names
executables := $(strip $(executables))
datafiles := $(strip $(datafiles))
datadirs := $(strip $(datadirs))

# Do not make any install sub-target with empty variable definition because the
# install program would exit with an error.
install: $(if $(executables), install-executables)
install: $(if $(datafiles), install-datafiles)
install: $(if $(datadirs), install-datadirs)

install-executables: all
	$(INSTALL_DIR) -v "$(installpath)"
	$(INSTALL_PROGRAM) $(executables) "$(installpath)"
	$(info ++++ info: executables of lib $(lib.name) installed \
        from $(CURDIR) to $(installpath))

install-datafiles: all
	$(INSTALL_DIR) -v "$(installpath)"
	$(INSTALL_DATA) $(datafiles) "$(installpath)"
	$(info ++++ info: data files of lib $(lib.name) installed \
        from $(CURDIR) to $(installpath))

install-datadirs: all
	$(foreach v, $(datadirs), $(INSTALL_DIR) "$(installpath)/$v";)
	$(foreach v, $(datadirs), \
        $(INSTALL_DATA) $(wildcard $v/*) "$(installpath)/$v";)
	$(info ++++ info: data directories of lib $(lib.name) installed \
        from $(CURDIR) to $(installpath))


################################################################################
### rules: distribution targets ################################################
################################################################################


# TODO
# These targets are implemented in Makefile Template, but I have to figure out
# how to do it under the not-so-strict conditions of Makefile.pdlibbuilder.

# make source package
dist:
	@echo "target dist not yet implemented"

# make Debian source package
dpkg-source:
	@echo "target dpkg-source not yet implemented"

$(ORIGDIR):

$(DISTDIR):


################################################################################
### rules: clean targets #######################################################
################################################################################


# delete build products from build tree
clean:
	rm -f $(all.objects)
	rm -f $(classes.executables) $(lib.name).$(extension) $(shared.lib)
	rm -f *.pre *.lst

# remove distribution directories and tarballs from build tree
distclean: clean
	@echo "target distclean not yet implemented"


################################################################################
### rules: submake targets #####################################################
################################################################################


# Iterate over sub-makefiles or makefiles in other directories.

# When 'continue-make=yes' is set, sub-makes will report 'true' to the parent
# process regardless of their real exit status. This prevents the parent make
# from being aborted by a sub-make error. Useful when you want to quickly find
# out which sub-makes from a large set will succeed.
ifeq ($(continue-make),yes)
  continue = || true
endif

# These targets will trigger sub-make processes for entries in 'makefiledirs'
# and 'makefiles'.
all alldebug install clean distclean dist dkpg-source: \
        $(makefiledirs) $(makefiles)

# this expands to identical rules for each entry in 'makefiledirs'
$(makefiledirs):
	$(MAKE) --directory=$@ $(MAKECMDGOALS) $(continue)

# this expands to identical rules for each entry in 'makefiles'
$(makefiles):
	$(MAKE) --directory=$(dir $@) --makefile=$(notdir $@) $(MAKECMDGOALS) $(continue)


################################################################################
### rules: convenience targets #################################################
################################################################################


#=== show variables ============================================================


# Several 'function' macro's cause errors when expanded within a rule or without
# proper arguments. Variables which are set with the define directive are only
# shown by name for that reason.
functions = \
add-class-source \
declare-class-target \
declare-class-executable-target \
declare-object-target \
link-class \
link-lib \
link-shared \
make-object-file \
make-preprocessor-file \
make-assembly-file


# show variables from makefiles
vars:
	$(info ++++ info: showing makefile variables:)
	$(foreach v,\
        $(sort $(filter-out $(functions) functions, $(.VARIABLES))),\
        $(if $(filter file, $(origin $v)),\
        $(info variable $v = $($v))))
	$(foreach v, $(functions), $(info 'function' name: $v))
	@echo

# show all variables
allvars:
	$(info ++++ info: showing default, automatic and makefile variables:)
	$(foreach v, \
        $(sort $(filter-out $(functions) functions, $(.VARIABLES))), \
        $(info variable ($(origin $v)) $v = $($v)))
	$(foreach v, $(functions), $(info 'function' name: $v))
	@echo


#=== show dependencies =========================================================


# show generated prerequisites rules
depend:
	$(info ++++ info: generated prerequisite rules)
	$(foreach v, $(classes), $(info $(declare-class-target)))
	$(foreach v, $(classes), $(info $(declare-class-executable-target)))
	$(foreach v, $(all.sources), $(info $(call declare-object-target, $v)))
	@echo


#=== show help text ============================================================


# brief info about targets and paths

mpdh := $(shell ls "$(pdincludepath)m_pd.h")
mpdh := $(if $(mpdh), $(mpdh),  m_pd.h not found. Is Pd(-extended) installed?)


help:
	@echo
	@echo "  Main targets:"
	@echo "    all:     build executables (default target)"
	@echo "    install: install all components of the library"
	@echo "    vars:    print makefile variables for troubleshooting"
	@echo "    allvars: print all variables for troubleshooting"
	@echo "    help:    print this help text"
	@echo
	@echo "  Pd API m_pd.h:"
	@echo "    $(shell ls "$(pdincludepath)m_pd.h")"
	@echo "  You may specify your preferred include path as argument to"
	@echo "  the make command, like 'pdincludepath=path/to/pd/src'."
	@echo
	@echo "  Path for installation of your libdir(s):"
	@echo "    $(objectsdir)"
	@echo "  Alternatively you may specify your path for installation as argument"
	@echo "  to the make command, like 'objectsdir=path/to/pd-externals'."
	@echo "  For detailed info read the doc sections in Makefile.pdlibbuilder."
	@echo


#=== dummy target ==============================================================


coffee:
	@echo "Makefile.pdlibbuilder: Can not make coffee. Sorry."


################################################################################
### end of rules sections ######################################################
################################################################################


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