Makefile.ext-CFLAGS

# #############################################################################
# LOC: Line-Of-Code: Makefile: build tests, example programs, run pytests
# SPDX-License-Identifier: Apache-2.0
#
# Developed based on SplinterDB (https://github.com/vmware/splinterdb) Makefile
# Copy of Makefile, to build just few source files, w/o defining CFLAGS
# inside this Makefile. Build command supplied CFLAGS as generated by the
# Py-gen script using --gen-cflags argument.
# #############################################################################

.DEFAULT_GOAL := all

help::
	@echo 'Usage: make [<target>]'
	@echo 'Supported targets: clean all run-tests run-test-code'

#
# Verbosity
#
ifndef BUILD_VERBOSE
   BUILD_VERBOSE=0
endif

# Setup echo formatting for messages.
ifeq "$(BUILD_VERBOSE)" "1"
   COMMAND=
   PROLIX=@echo
   BRIEF=@ >/dev/null echo
   BRIEF_FORMATTED=@ >/dev/null echo
   BRIEF_PARTIAL=@echo -n >/dev/null
else ifeq "$(BUILD_VERBOSE)" "0"
   COMMAND=@
   PROLIX=@ >/dev/null echo
   BRIEF=@echo
   BRIEF_FORMATTED=@printf
   BRIEF_PARTIAL=@echo -n
else
   $(error Unknown BUILD_VERBOSE mode "$(BUILD_VERBOSE)".  Valid values are "0" or "1". Default is "0")
endif

# Compilers to use
CXX ?= g++
LD  ?= g++

# ###################################################################
# SOURCE DIRECTORIES AND FILES, Generator Package
#
LOCPACKAGE           = loc
TEST_CODE            = test-code
LOCGENPY             = $(LOCPACKAGE)/gen_loc_files.py

# ###################################################################
# BUILD DIRECTORIES AND FILES
#
ifndef BUILD_ROOT
   BUILD_ROOT := build
endif

#
# Build mode
#
ifndef BUILD_MODE
   BUILD_MODE=release
endif
BUILD_DIR := $(BUILD_MODE)

BUILD_PATH=$(BUILD_ROOT)/$(BUILD_DIR)

OBJDIR = $(BUILD_PATH)/obj
BINDIR = $(BUILD_PATH)/bin

# ##############################################################################
# All the generated files (source and header files)
# Ref: https://stackoverflow.com/questions/37781449/including-generated-files-in-makefile-dependencies
# ##############################################################################
# If you list both .h & .c file, generator gets triggered twice. List just one.
SINGLE_FILE_CC_PROGRAM_GENSRC := $(TEST_CODE)/single-file-cc-program/loc_filenames.c

# For this test Makefile, we have just one dependent generated source
GENERATED := $(SINGLE_FILE_CC_PROGRAM_GENSRC)

# ------------------------------------------------------------------------------
# Rule: Use Python generator script to generate the LOC-files
# Rule will be triggered for objects defined to be dependent on $(GENERATED) sources.
# Use the triggering target's dir-path to generate .h / .c files
# ------------------------------------------------------------------------------
$(GENERATED):
	@echo
	@echo "Invoke LOC-generator triggered by: " $@
	$(LOCGENPY) --gen-includes-dir  $(dir $@) --gen-source-dir $(dir $@) --src-root-dir $(dir $@) --verbose
	@echo

# The rules to generate object files from the generated source files
GENERATED_SRCS := $(filter %.c,$(GENERATED))
GENERATED_OBJS := $(GENERATED_SRCS:%.c=$(OBJDIR)/%.o)

# ###################################################################
# SOURCE DIRECTORIES AND FILES

# ---- Symbols to build test-code sample programs
# -- Pick-up just the C++ sources, used for this test Make procedure
TEST_CODE_SRC := $(shell find $(TEST_CODE) -type f -name *.cc -print)

# -- Sequentially replace src-file extension to generate list of .o's
TEST_CODE_OBJS := $(TEST_CODE_SRC:%.cc=$(OBJDIR)/%.o)

# Grab the "main.c" for each test-code sample program, which will be used
# to construct the list of test-code binaries.
TEST_CODE_BIN_SRC=$(filter %-main.cc, $(TEST_CODE_SRC))

# ----------------------------------------------------------------------------
# Generate location / name of test-code sample program binary, using built-in
# substitution references. test-code/ has sources like:
#
#   test-code/single-file-cc-program/single-file-main.cc
#
# Convert this list of *main.c to generate test-code program binary names,
# using the src-dir's name as the program name:
#   build/release/bin/test-code/single-file-cc-program
#
TEST_CODE_BINS_TMP := $(TEST_CODE_BIN_SRC:$(TEST_CODE)/%-main.cc=$(BINDIR)/$(TEST_CODE)/%-program)
TEST_CODE_BINS=$(patsubst %program/, %program, $(dir $(TEST_CODE_BINS_TMP)) )

# ###################################################################
# Report build machine details and compiler version for troubleshooting,
# so we see this output for clean builds, especially in CI-jobs.
# ###################################################################
.PHONY : clean tags
clean:
	uname -a
	$(CXX) --version
	rm -rf $(BUILD_ROOT)
	find . \( -name "*loc*.c" -o -name "loc*.h" \)  -exec rm -rf {} \;

####################################################################
# The main targets
#
all: all-test-code
all-test-code: $(TEST_CODE_BINS)

# ###################################################################
# CFLAGS, LDFLAGS, ETC
#
# -----------------------------------------------------------------------------
# NOTE: Normally we would define this here, so that all source files that
#       use LOC-macros would compile cleanly. But the objective of this
#       test Makefile is to demonstrate how-to pass CFLAGS externally
#       while building the code. Hence, this definition is commented out.
#
# Define CFLAGS to generate the -D clause to define LOC_FILE_INDEX
# using the source file name as input:
#  - Replace "-" in filename with "_"
#  - Replace "." with "_" (*.c -> *_c, *.cpp -> *_cpp, *.cc -> *_cc)
# -----------------------------------------------------------------------------
# CFLAGS=-DLOC_FILE_INDEX=LOC_$(subst .,_,$(subst -,_,$(notdir $<)))

# -----------------------------------------------------------------------------
# Define the include files' dir-path.
# The LOC-generated .h files will appear in each test-code program's src-dir.
# Use this recursively defined variables to build the path to pick-up both
# forms of #include .h files.
# -----------------------------------------------------------------------------
INCLUDE = -I ./$(dir $<)

# use += here, so that extra flags can be provided via the environment

CFLAGS += -D_GNU_SOURCE -ggdb3 -Wall -Wfatal-errors -Werror

# ###################################################################
# Automatically create directories, based on
# http://ismail.badawi.io/blog/2017/03/28/automatic-directory-creation-in-make/
.SECONDEXPANSION:

.SECONDARY:

%/.:
	$(COMMAND) mkdir -p $@

# These targets prevent circular dependencies arising from the
# recipe for building binaries
$(BINDIR)/.:
	$(COMMAND) mkdir -p $@

$(BINDIR)/%/.:
	$(COMMAND) mkdir -p $@

# ###################################################################
# Dependencies
#
$(GENERATED_OBJS): $(GENERATED)

# ###################################################################
# The dependencies for each test-code sample program
# Every example program of the form bin/test-code/<eg-prog> depends on
# obj/test-code/<eg-prog>/*.o -> *.c
# There can be more than one .o's linked to create test-code example
# program.

# ----
SINGLE_FILE_CC_PROGRAM_TESTSRC := $(shell find $(TEST_CODE)/single-file-cc-program -type f -name *.cc -print)
SINGLE_FILE_CC_PROGRAM_TESTSRC += $(SINGLE_FILE_CC_PROGRAM_GENSRC)

SINGLE_FILE_CC_PROGRAM_OBJS := $(SINGLE_FILE_CC_PROGRAM_TESTSRC:%.cc=$(OBJDIR)/%.o)
$(BINDIR)/$(TEST_CODE)/single-file-cc-program: $(SINGLE_FILE_CC_PROGRAM_OBJS)

$(SINGLE_FILE_CC_PROGRAM_OBJS): $(GENERATED_OBJS)

# ###################################################################
# RECIPES:

# For all-test-code, we need to use -I test-code/<subdir>
# Dependencies for the main executables
COMPILE.cc  = $(CXX) $(CFLAGS) $(INCLUDE) -c

# ----
# Compile each .cc file into its .o
# Also define a dependency on the dir in which .o will be produced (@D).
# The secondary expansion will invoke mkdir to create output dirs first.
$(OBJDIR)/%.o: %.cc | $$(@D)/.
	$(BRIEF_FORMATTED) "%-20s %-50s [%s]\n" Compiling $< $@
	$(COMMAND) $(COMPILE.cc) $< -o $@
	$(PROLIX) # blank line

# ----
# Link .o's to product running binary
# Define dependency on output dir existing, so secondary expansion will
# trigger mkdir to create bin/s output dir.
# If you add "$^" to 'Linking' message, you will see list of .o's being linked
$(BINDIR)/%: | $$(@D)/.
	$(BRIEF_FORMATTED) "%-20s %s\n" Linking $@
	$(COMMAND) $(LD) $(LDFLAGS) $^ -o $@ $(LIBS)
	$(PROLIX) # blank line

# ----
ifeq "$(BUILD_VERBOSE)" "1"
	@echo
	$(info $$TEST_CODE_SRC     = [${TEST_CODE_SRC}])
	$(info $$TEST_CODE_OBJS    = [${TEST_CODE_OBJS}])
	$(info $$TEST_CODE_BIN_SRC = [${TEST_CODE_BIN_SRC}])
	$(info $$TEST_CODE_BINS    = [${TEST_CODE_BINS}])
	$(info $$GENERATED_OBJS    = [${GENERATED_OBJS}])
endif

# ###################################################################
# Testing
#

.PHONY: install

run-tests: run-test-code
run-test-code: all-test-code
	@echo
	@echo "**** Run sample test-code programs ****"
	for i in $(TEST_CODE_BINS); do echo " "; echo "-- Executing $$i";$$i || exit;  done