# -*- makefile -*-
# vim: set filetype=make :
# Copyright 2022 The ChromiumOS Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
#
# Embedded Controller firmware build system - IDE support
#
# One caveat with this approach is that we still don't capture modified make
# variables that are associated with a specific build target, like the following:
#
# $(out)/RW/common/blah.o: CFLAGS += -g
#
# This is because our compile commands json targets will not match this rule.

# If env EXTERNAL_TRUNK_PATH is defined, we use this to build the
# absolute path to the ec directory. Otherwise, we just take the abspath of ".".
ide-ec-path-ext = \
	$(if $(EXTERNAL_TRUNK_PATH),$(EXTERNAL_TRUNK_PATH)/src/platform/ec)
ide-ec-path-abs = $(abspath .)
ide-ec-path = $(or $(ide-ec-path-ext),$(ide-ec-path-abs))

# Clang doesn't support these GCC options.
ide-filters = -mno-sched-prolog -fconserve-stack

# The complete compile_commands.json targets.
ide-compile-cmds-y                        = $(out)/RW/compile_commands.json
ide-compile-cmds-$(CONFIG_FW_INCLUDE_RO) += $(out)/RO/compile_commands.json
ide-compile-cmds-y                       += $(out)/util/compile_commands.json

# All individual <src_file>.compile_cmds.json targets.
ide-rw-objs = $(rw-objs:.o=.compile_cmd.json)
ide-ro-objs = $(ro-objs:.o=.compile_cmd.json)

ide-build-utils    = $(build-utils:=.compile_cmd.json)
ide-host-utils     = $(host-utils:=.compile_cmd.json)
ide-host-utils-cxx = $(host-utils-cxx:=.compile_cmd.json)

ide-utils = $(ide-build-utils) $(ide-host-utils) $(ide-host-utils-cxx)

# The all-ide-compile-cmds target takes about 2 minutes using 8 cores when all
# work is replaced by the |true| command. Thus, the build system itself
# takes 2m independent of the text manipulation.
.PHONY: all-ide-compile-cmds
all-ide-compile-cmds: $(foreach b, $(BOARDS), ide-compile-cmds-$(b))
ide-compile-cmds-%:
	$(MAKE) BOARD=$* V=$(V) ide-compile-cmds

.PHONY: ide-compile-cmds
ide-compile-cmds: $(ide-compile-cmds-y)

# All but the last file/json-object need to have a trailing comma.
#
# The first sed line prepends 4 spaces to all lines and then adds a
# comma + implicit-newline to the end of the last line of the file.
# The second sed line prepends 4 spaces to all lines and then adds an
# implicit new line.
cmd_combine_compile_cmd_json =                                                 \
	printf '[\n'                                                      >$@ ;\
	echo $^ | xargs -n1 | head -n-1 | xargs -n1 sed 's/^/    /;$$s/$$/,/'  \
									 >>$@ ;\
	sed 's/^/    /' $(lastword $^)                                   >>$@ ;\
	printf ']\n'                                                     >>$@ ;

$(out)/RW/compile_commands.json: override BLD := RW
$(out)/RW/compile_commands.json: private objs := $(rw-objs)
$(out)/RW/compile_commands.json: $(ide-rw-objs)
$(out)/RW/compile_commands.json: $(ide-utils)
	$(call quiet,combine_compile_cmd_json,COMBINE)
$(out)/RO/compile_commands.json: override BLD := RO
$(out)/RO/compile_commands.json: private objs := $(ro-objs)
$(out)/RO/compile_commands.json: $(ide-ro-objs)
$(out)/RO/compile_commands.json: $(ide-utils)
	$(call quiet,combine_compile_cmd_json,COMBINE)
$(out)/util/compile_commands.json: $(ide-utils)
	$(call quiet,combine_compile_cmd_json,COMBINE)

# Quote all words and add a comma between words.
# The quotes are applied as \", so that they will escape shell removal.
#
# $(1) - The space separated list of words.
ide-comma = ,
ide-space = $() $()
ide-esc-quoted = $(patsubst %,\"%\",$(1))
cmd_json_list = $(subst $(ide-space),$(ide-comma)$(ide-space),$(ide-esc-quoted))

# Replace any ".compile_cmd.json" with ".o" and filter out $(ide-filters) words.
# The replace is needed because we are invoking build commands from within our
# make rules that have targets set to files of type .compile_cmd.json.
# The compile commands will use special variables that pull this name into
# the command.
#
# $(1) - The compilation command.
# $(2) - The original target extension, like ".o" or "".
cmd_rep_filter = $(subst .compile_cmd.json,$(2),$(filter-out $(ide-filters),$(1)))

# Form a compile command JSON block.
#
# $(1) - Used by quiet function, but it is this command name.
# $(2) - Used by quiet function, but it is the pretty action label.
# $(3) - The compilation command to place in the JSON blob.
# $(4) - The original target extension, like ".o" or "".
# $(5) - The source file this compile command applies to.
cmd_to_compile_cmd_json =                                                      \
	printf '{\n'                                                     >$@  ;\
	printf '    "arguments": [\n'                                   >>$@  ;\
	printf '        %s\n'                                                  \
	  $(call cmd_json_list,$(call cmd_rep_filter,$(3),$(4)))        >>$@  ;\
	printf '    ],\n'                                               >>$@  ;\
	printf '    "directory": "$(ide-ec-path)",\n'                   >>$@  ;\
	printf '    "file": "$(5)"\n'                                   >>$@  ;\
	printf '}\n'                                                    >>$@  ;

# Disable ccache, since this is only going to control whether the ccache
# executable shows in the compile_commands.json file.
%.compile_cmd.json: CCACHE :=

$(out)/RO/%.compile_cmd.json:%.c
	$(call quiet,to_compile_cmd_json,JSON   ,$(cmd_c_to_o),.o,$<)
$(out)/RW/%.compile_cmd.json:%.c
	$(call quiet,to_compile_cmd_json,JSON   ,$(cmd_c_to_o),.o,$<)

$(out)/RO/%.compile_cmd.json:%.cc
	$(call quiet,to_compile_cmd_json,JSON   ,$(cmd_cxx_to_o),.o,$<)
$(out)/RW/%.compile_cmd.json: %.cc
	$(call quiet,to_compile_cmd_json,JSON   ,$(cmd_cxx_to_o),.o,$<)

$(out)/RO/%.compile_cmd.json:%.S
	$(call quiet,to_compile_cmd_json,JSON   ,$(cmd_c_to_o),.o,$<)
$(out)/RW/%.compile_cmd.json:%.S
	$(call quiet,to_compile_cmd_json,JSON   ,$(cmd_c_to_o),.o,$<)

$(ide-build-utils): $(out)/%.compile_cmd.json:$(build-srcs)
	$(call quiet,to_compile_cmd_json,JSON   ,$(cmd_c_to_build),\
		$(EMPTY),$*.c)

$(ide-host-utils): $(out)/%.compile_cmd.json:$(host-srcs)
	$(call quiet,to_compile_cmd_json,JSON   ,$(cmd_c_to_host),\
		$(EMPTY),$*.c)

$(ide-host-utils-cxx): $(out)/%.compile_cmd.json:$(host-srcs-cxx)
	$(call quiet,to_compile_cmd_json,JSON   ,$(cmd_cxx_to_host),\
		$(EMPTY),$*.cc)