esp-idf/make/component_wrapper.mk

# Component wrapper makefile
#
# This makefile gets called recursively from the project make, once for each component.
# COMPONENT_MAKEFILE is set to point at the component.mk file for the component itself,
# which is included as part of this process (after default variables are defined).
#
# This makefile comprises multiple stages, marked in blocked comments below.
#
# CWD is the build directory of the component.

ifndef PROJECT_PATH
$(error Make was invoked from $(CURDIR). However please do not run make from the sdk or a component directory; invoke make from the project directory. See the ESP-IDF README for details.)
endif


################################################################################
# 1) Set default variables for the component build (including configuration
#	loaded from sdkconfig.)
################################################################################

# Find the path to the component
COMPONENT_PATH := $(abspath $(dir $(COMPONENT_MAKEFILE)))
export COMPONENT_PATH

# COMPONENT_BUILD_DIR is otherwise known as CWD for the build
COMPONENT_BUILD_DIR := $(abspath .)

# include elements common to both project & component makefiles
# (includes project configuration set via menuconfig)
include $(IDF_PATH)/make/common.mk

# Some of the following defaults may be overriden by the component's component.mk makefile,
# during the next step:

# Name of the component
COMPONENT_NAME := $(lastword $(subst /, ,$(realpath $(COMPONENT_PATH))))

# Absolute path of the .a file
COMPONENT_LIBRARY = lib$(COMPONENT_NAME).a

# Source dirs a component has. Default to root directory of component.
COMPONENT_SRCDIRS = .

# By default, include only the include/ dir.
COMPONENT_ADD_INCLUDEDIRS = include
COMPONENT_ADD_LDFLAGS = -l$(COMPONENT_NAME)


################################################################################
# 2) Include the component.mk for the specific component (COMPONENT_MAKEFILE) to
#     override variables & optionally define custom targets.
################################################################################

include $(COMPONENT_MAKEFILE)


################################################################################
# 3) Set variables that depend on values that may changed by component.mk
################################################################################

# Object files which need to be linked into the library
# By default we take all .c, .cpp & .S files in COMPONENT_SRCDIRS.
ifndef COMPONENT_OBJS
# Find all source files in all COMPONENT_SRCDIRS
COMPONENT_OBJS := $(foreach compsrcdir,$(COMPONENT_SRCDIRS),$(patsubst %.c,%.o,$(wildcard $(COMPONENT_PATH)/$(compsrcdir)/*.c)))
COMPONENT_OBJS += $(foreach compsrcdir,$(COMPONENT_SRCDIRS),$(patsubst %.cpp,%.o,$(wildcard $(COMPONENT_PATH)/$(compsrcdir)/*.cpp)))
COMPONENT_OBJS += $(foreach compsrcdir,$(COMPONENT_SRCDIRS),$(patsubst %.S,%.o,$(wildcard $(COMPONENT_PATH)/$(compsrcdir)/*.S)))
# Make relative by removing COMPONENT_PATH from all found object paths
COMPONENT_OBJS := $(patsubst $(COMPONENT_PATH)/%,%,$(COMPONENT_OBJS))
endif

# If we're called to compile something, we'll get passed the COMPONENT_INCLUDES
# variable with all the include dirs from all the components in random order. This
# means we can accidentally grab a header from another component before grabbing our own.
# To make sure that does not happen, re-order the includes so ours come first.
OWN_INCLUDES:=$(abspath $(addprefix $(COMPONENT_PATH)/,$(COMPONENT_ADD_INCLUDEDIRS) $(COMPONENT_PRIV_INCLUDEDIRS)))
COMPONENT_INCLUDES := $(OWN_INCLUDES) $(filter-out $(OWN_INCLUDES),$(COMPONENT_INCLUDES))


################################################################################
# 4) Define a target to generate component_project_vars.mk Makefile which
# contains common per-component settings which are included directly in the
# top-level project make
################################################################################

# macro to generate variable-relative paths inside component_project_vars.mk, whenever possible
# ie put literal $(IDF_PATH), $(PROJECT_PATH) and $(BUILD_DIR_BASE) into the generated
# makefiles where possible.
#
# This means if directories move (breaking absolute paths), don't need to 'make clean'
define MakeVariablePath
$(subst $(IDF_PATH),$$(IDF_PATH),$(subst $(PROJECT_PATH),$$(PROJECT_PATH),$(subst $(BUILD_DIR_BASE),\$$(BUILD_DIR_BASE),$(1))))
endef

# component_project_vars.mk target for the component. This is used to
# take component.mk variables COMPONENT_ADD_INCLUDEDIRS,
# COMPONENT_ADD_LDFLAGS and COMPONENT_DEPENDS and inject those into
# the project make pass.
#
# The target here has no dependencies, as the parent target in
# project.mk evaluates dependencies before calling down to here. See
# GenerateComponentTargets macro in project.mk.
#
# If you are thinking of editing the output of this target for a
# component-specific feature, please don't! What you want is a
# Makefile.projbuild for your component (see docs/build-system.rst for
# more.)
component_project_vars.mk::
	$(details) "Building component project variables list $(abspath $@)"
	@echo '# Automatically generated build file. Do not edit.' > $@
	@echo 'COMPONENT_INCLUDES += $(call MakeVariablePath,$(addprefix $(COMPONENT_PATH)/,$(COMPONENT_ADD_INCLUDEDIRS)))' >> $@
	@echo 'COMPONENT_LDFLAGS += $(call MakeVariablePath,$(COMPONENT_ADD_LDFLAGS))' >> $@
	@echo '$(COMPONENT_NAME)-build: $(addsuffix -build,$(COMPONENT_DEPENDS))' >> $@


################################################################################
# 5) If COMPONENT_OWNBUILDTARGET / COMPONENT_OWNCLEANTARGET is not set by component.mk,
#	define default build, clean, etc. targets
################################################################################

# If COMPONENT_OWNBUILDTARGET is not set, define a phony build target and
# a COMPONENT_LIBRARY link target.
ifndef COMPONENT_OWNBUILDTARGET
.PHONY: build
build: $(COMPONENT_LIBRARY)
	@mkdir -p $(COMPONENT_SRCDIRS)

# Build the archive. We remove the archive first, otherwise ar will get confused if we update
# an archive when multiple filenames have the same name (src1/test.o and src2/test.o)
$(COMPONENT_LIBRARY): $(COMPONENT_OBJS)
	$(summary) AR $@
	$(Q) rm -f $@
	$(Q) $(AR) cru $@ $(COMPONENT_OBJS)
endif

# If COMPONENT_OWNCLEANTARGET is not set, define a phony clean target
ifndef COMPONENT_OWNCLEANTARGET
CLEAN_FILES = $(COMPONENT_LIBRARY) $(COMPONENT_OBJS) $(COMPONENT_OBJS:.o=.d) $(COMPONENT_EXTRA_CLEAN) component_project_vars.mk
.PHONY: clean
clean:
	$(summary) RM $(CLEAN_FILES)
	$(Q) rm -f $(CLEAN_FILES)
endif

# Include all dependency files already generated
-include $(COMPONENT_OBJS:.o=.d)

# This pattern is generated for each COMPONENT_SRCDIR to compile the files in it.
define GenerateCompileTargets
# $(1) - directory containing source files, relative to $(COMPONENT_PATH)
$(1)/%.o: $$(COMPONENT_PATH)/$(1)/%.c | $(1)
	$$(summary) CC $$@
	$$(Q) $$(CC) $$(CFLAGS) $$(CPPFLAGS) $$(addprefix -I ,$$(COMPONENT_INCLUDES)) $$(addprefix -I ,$$(COMPONENT_EXTRA_INCLUDES)) -I$(1) -c $$< -o $$@

$(1)/%.o: $$(COMPONENT_PATH)/$(1)/%.cpp | $(1)
	$$(summary) CXX $$@
	$$(Q) $$(CXX) $$(CXXFLAGS) $$(CPPFLAGS) $$(addprefix -I,$$(COMPONENT_INCLUDES)) $$(addprefix -I,$$(COMPONENT_EXTRA_INCLUDES)) -I$(1) -c $$< -o $$@

$(1)/%.o: $$(COMPONENT_PATH)/$(1)/%.S | $(1)
	$$(summary) AS $$@
	$$(Q) $$(CC) $$(CPPFLAGS) $$(addprefix -I ,$$(COMPONENT_INCLUDES)) $$(addprefix -I ,$$(COMPONENT_EXTRA_INCLUDES)) -I$(1) -c $$< -o $$@

# CWD is build dir, create the build subdirectory if it doesn't exist
$(1):
	@mkdir -p $(1)
endef

# Generate all the compile target patterns
$(foreach srcdir,$(COMPONENT_SRCDIRS), $(eval $(call GenerateCompileTargets,$(srcdir))))