Makefile.common.header

# -*- Makefile -*-

# This is a part of the mrbuild project: https://github.com/dkogan/mrbuild
#
# Released under an MIT-style license. Modify and distribute as you like:
#
# Copyright 2016-2019 California Institute of Technology
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

# osx
COND_DARWIN := $(filter Darwin,$(shell uname -s))
SO          := $(if $(COND_DARWIN),dylib,so)



# Hacks to get spaces and newlines in places where Make would normally parse
# them out
SPACE :=
SPACE := $(SPACE) $(SPACE)
define NEWLINE


endef

dirs_to_dotdot = $(subst $(SPACE),/,$(patsubst %,..,$(subst /, ,$1)))
get_parentdir_relative_to_childdir = /$(call dirs_to_dotdot,$(patsubst $1%,%,$2))

RPATH_SUFFIX = $(call get_parentdir_relative_to_childdir,$(abspath .),$(dir $(abspath $1)))
ifeq ($(COND_DARWIN),)
  RPATH = '$$ORIGIN'$(RPATH_SUFFIX)
else
  RPATH = @executable_path$(RPATH_SUFFIX)
endif

RPATH_OPTION = -Wl,-rpath,$(call RPATH,$@)





# This stuff defines variables (PY_EXT_SUFFIX) that could be used by the user
# Makefile at parsing time. So this must be included BEFORE the rest of the user
# Makefile

PYTHON_VERSION_FOR_EXTENSIONS ?= 3 # 2 or 3
# Flags for python extension modules. See
# http://notes.secretsauce.net/notes/2017/11/14_python-extension-modules-without-setuptools-or-distutils.html
#
# I build the python extension module without any setuptools or anything.
# Instead I ask python about the build flags it likes, and build the DSO
# normally using those flags.
#
# There's some sillyness in Make I need to work around. First, I produce a
# python script to query the various build flags, but replacing all whitespace
# with __whitespace__. The string I get when running this script will then have
# a number of whitespace-separated tokens, each setting ONE variable
#
# I set up a number of variables:
#
#   These come from Python queries. I ask Python about XXX and store the result
#   into PY_XXX
#
#     PY_CC
#     PY_CFLAGS
#     PY_CCSHARED
#     PY_INCLUDEPY
#     PY_BLDSHARED
#     PY_LDFLAGS
#     PY_EXT_SUFFIX
#     PY_MULTIARCH
#
#  These process the above into a single set of CFLAGS:
#
#    PY_MRBUILD_CFLAGS
#
#  These process the above into a single set of LDFLAGS:
#
#    PY_MRBUILD_LDFLAGS
#
#  These process the above into a DSO-building linker command
#
#    PY_MRBUILD_LINKER
#
# When the user Makefile evaluates ANY of these variables I query python, and
# memoize the results. So the python is invoked at MOST one time. Any Makefiles
# that don't touch the PY_... variables will not end up invoking the python
# thing at all
#
# Variables to ask Python about
_PYVARS_LIST := CC CFLAGS CCSHARED INCLUDEPY BLDSHARED BLDLIBRARY LDFLAGS EXT_SUFFIX MULTIARCH

ifneq ($(DEB_HOST_MULTIARCH),)
  # We have a debian multiarch. We're almost certainly cross-building with
  # Debian. Try to get the variables directly, using any-architecture python
  define _PYVARS_GET_CONFIG :=
import ast
import sys

prefixes = ("_sysconfigdata_", "_sysconfigdata_m_linux")
sysconfig_paths = [d + "/" + prefix + "_$(DEB_HOST_MULTIARCH).py" for d in sys.path for prefix in prefixes]
for filename in sysconfig_paths:
    try:
        f = open(filename)
    except:
        continue

    s = f.read()
    s = re.sub("^#.*",                "", s, flags=re.M)
    s = re.sub("^[0-9a-zA-Z_]+ *= *", "", s, flags=re.M)
    conf = ast.literal_eval(s)
    break
else:
    raise Exception("Could not find sysconfig file in any sys.path directories. Tried: {}".format(sysconfig_paths))
endef

else
  _PYVARS_GET_CONFIG := conf = sysconfig.get_config_vars()
endif


# Python script to query those variables
define _PYVARS_SCRIPT
from __future__ import print_function
import sysconfig
import re

# get "conf" dict
$(_PYVARS_GET_CONFIG)

for v in ($(foreach v,$(_PYVARS_LIST),"$v",)):
    if v in conf:
        print(re.sub("[\t ]+", "__whitespace__", "_PY_{}:={}".format(v, conf[v])))
endef

# I eval this to actually invoke the Python and to ingest its results. I only
# eval this ONLY when necessary.
define query_python_extension_building_flags
_PYVARS = $(shell python$(PYTHON_VERSION_FOR_EXTENSIONS) -c '$(_PYVARS_SCRIPT)')
# I then $(eval) these tokens one at a time, restoring the whitespace
$(foreach setvarcmd,$(_PYVARS),$(eval $(subst __whitespace__, ,$(setvarcmd))))
# Add the numpy include path. See https://bugs.debian.org/1067398
_PY_INCLUDEPY += $(shell $(or $(PKG_CONFIG),pkg-config) --cflags-only-I numpy 2>/dev/null)
# pull out flags from CC, throw out the compiler itself, since I know better
_FLAGS_FROM_PYCC    = $(wordlist 2,$(words $(_PY_CC)),$(_PY_CC))
_PY_MRBUILD_CFLAGS  = $(filter-out -O%,$(_FLAGS_FROM_PYCC) $(_PY_CFLAGS) $(_PY_CCSHARED) -I$(_PY_INCLUDEPY))

# In the python api I have to cast a PyCFunctionWithKeywords to a PyCFunction,
# and the compiler complains. But that's how Python does it! So I tell the
# compiler to chill
_PY_MRBUILD_CFLAGS += -Wno-cast-function-type
# similarly, with gcc-14 I get this without turning off this warning:
#   /usr/include/python3.12/object.h:142:9: error: initialization of 'long int' from 'void *' makes integer from pointer without a cast [-Wint-conversion]
_PY_MRBUILD_CFLAGS += -Wno-int-conversion

# This is how we link the extension module DSOs. Note that we do NOT link with
# -lpython, or anything of the sort (from $(_PY_BLDLIBRARY)). This isn't
# strictly necessary because this will only be linked from the python
# executable, so the library will already be loaded. And in some situations
# (static linking), passing $(_PY_BLDLIBRARY) by itself doesn't actually work:
#   https://github.com/dkogan/mrcal/issues/22
_PY_MRBUILD_LDFLAGS = $(RPATH_OPTION) $(_PY_LDFLAGS) -L$(abspath .)
_PY_MRBUILD_LINKER  = $(_PY_BLDSHARED)
endef

# List of variables a user Makefile could touch. These are all PY_...
_PYVARS_API := $(foreach v,$(_PYVARS_LIST),PY_$v) PY_MRBUILD_CFLAGS PY_MRBUILD_LDFLAGS PY_MRBUILD_LINKER

# The first time the user touches these variables, ask Python. Each subsequent
# time, use the previously-returned value. So we query Python at most once. If a
# project isn't using the Python extension modules, we will not query Python at
# all
#
# I handle all the Python API variables identically, except for PY_EXT_SUFFIX.
# If Python gives me a suffix, I use it (this is available in python3; it has
# ABI, architecture details). Otherwise, I try the multiarch suffix, or if even
# THAT isn't available, just do .so. I need to handle it specially to make the
# self-referential logic work with the memoization logic
define _PY_DEFINE_API_VAR
$1 = $$(or $$(_$1),$$(eval $$(value query_python_extension_building_flags))$$(_$1))
endef
define _PY_DEFINE_API_VAR_EXTSUFFIX
$1 = $$(or $$(_$1),$$(eval $$(value query_python_extension_building_flags))$$(or $$(_$1),$$(if $$(PY_MULTIARCH),.$$(PY_MULTIARCH)).$$(SO)))
endef

$(foreach v,$(filter-out PY_EXT_SUFFIX,$(_PYVARS_API)),$(eval $(call _PY_DEFINE_API_VAR,$v)))
$(eval $(call _PY_DEFINE_API_VAR_EXTSUFFIX,PY_EXT_SUFFIX))



# Useful to pull in a local build of some library. For testing. Sets the
# compiler and linker (runtime and build-time) flags. Invoke like this:
#   $(eval $(call add_local_library_path,/home/user/library))
define add_local_library_path
CFLAGS   += -I$1
CXXFLAGS += -I$1
LDFLAGS  += -L$1
LDFLAGS += -Wl,-rpath,$1
endef




#### VERSION_FROM_PROJECT variable: parse git tags or, if those aren't
#### available, the debian/changelog. To use this, add to your Makefile:
####
####   VERSION := $(VERSION_FROM_PROJECT)
####
#### Otherwise, we'll use $(ABI_VERSION).$(TAIL_VERSION). VERSION_FROM_PROJECT
#### is useful in mature-ish projects that are actually being distributed to
#### others
# "git describe --tags" says things like "v2.0-17-gcef328f". This converts it to "v2.0"
_VERSION_STRIP_POST_TAG_ANNOTATIONS := s/-\d+-g[0-9a-f]+$$//
# I might have a tag such as "debian/2.0-1". This converts it to "2.0-1"
_VERSION_STRIP_LEADING_PATH         := s/^.*\///
# I might have a tag such as "v2.0". This converts it to "2.0"
_VERSION_STRIP_LEADING_V            := s/^v//g

# Custom version from git (or from debian/changelog if no git repo available)

# If user says "VERSION_USE_LATEST_TAG=1 make" I'll use the latest tag for the
# version, without annotations about the subsequent commits
PAREN0 := (
PAREN1 := )
_VERSION = $(shell															\
  if test -e debian/changelog; then													\
      < debian/changelog perl -ane 'if($$F[1] =~ /^\$(PAREN0)(.+)\$(PAREN1)$$/) { print $$1 } else { print "VERSION_UNKNOWN"}; exit 0';	\
  elif test -d .git && git describe --tags >/dev/null 2>/dev/null; then									\
      git describe --tags |														\
      perl -pe '$(if $(VERSION_USE_LATEST_TAG),$(_VERSION_STRIP_POST_TAG_ANNOTATIONS));							\
		$(_VERSION_STRIP_LEADING_PATH);												\
		$(_VERSION_STRIP_LEADING_V);';												\
  else																	\
    echo "VERSION_UNKNOWN";														\
  fi																	\
)

# Memoize. $(VERSION) will evaluate the result the first time, and use the
# cached result during subsequent calls
VERSION_FROM_PROJECT = $(if $(_VERSION_EXPANDED),,$(eval _VERSION_EXPANDED:=$$(_VERSION)))$(_VERSION_EXPANDED)