#!/usr/bin/make -f
#
# \brief  Function implementation creation tool for DDE Linux
# \author Stefan Kalkowski
# \date   2021-03-11
#

help:
	$(ECHO) ""
	$(ECHO) "Create function implementation dummies for DDE Linux"
	$(ECHO) ""
	$(ECHO) "usage:"
	$(ECHO) ""
	$(ECHO) "  create_dummies <command> [VARIABLES]"
	$(ECHO) ""
	$(ECHO) "--- available commands ---"
	$(ECHO) "help         - shows this help"
	$(ECHO) "show         - shows missing symbols of given TARGET"
	$(ECHO) "generate     - generates DUMMY_FILE for given TARGET"
	$(ECHO) ""
	$(ECHO) "--- used variables ---"
	$(ECHO) "TARGET            - denotes the Genode build target"
	$(ECHO) "BUILD_DIR         - optional path to Genode build directory,"
	$(ECHO) "                    used to build the TARGET"
	$(ECHO) "                    (default is the current path)"
	$(ECHO) "LINUX_KERNEL_DIR  - path to the Linux kernel build"
	$(ECHO) "DUMMY_FILE        - path to the file that shall be generated"
	$(ECHO) "ARCH              - is optional, normally it is tried"
	$(ECHO) "                    to extract it from BUILD_DIR"
	$(ECHO) ""


COMMAND := $(firstword $(MAKECMDGOALS))

SHELL        = bash
BRIGHT_COL   = \033[01;33m
DEFAULT_COL  = \033[0m
ECHO         = @echo -e
BUILD_DIR   ?= $(PWD)


# There are some expensive commands defined underneath,
# which shouldn't be executed when calling for help
ifneq ($(COMMAND),help)

#
# Sanity checks
#

ifeq ($(TARGET),)
$(error You have to state a valid build TARGET, try help)
endif

##
# Return $(2) if $(1) is empty, "" else
#
check_nonempty_f = $(if $(1),,$(info $(2))$(2))

CTAGS_OK = $(call check_nonempty_f,$(shell which ctags),\
             Need to have ctags installed.)


TOOLS_OK = $(CTAGS_OK)

ifneq ($(strip $(TOOLS_OK)),)
$(error Please install missing tools.)
endif

ifneq ($(realpath $(BUILD_DIR)/etc/specs.conf),)
ARCH ?= $(word 3,$(shell grep "SPECS" $(BUILD_DIR)/etc/specs.conf))
endif

ifeq ($(ARCH),arm_v6)
TOOL_ARCH = arm
LX_ARCH   = arm
else
ifeq ($(ARCH),arm_v7a)
TOOL_ARCH = arm
LX_ARCH   = arm
else
ifeq ($(ARCH),arm_v8a)
TOOL_ARCH = aarch64
LX_ARCH   = arm64
else
ifeq ($(ARCH),x86_32)
TOOL_ARCH = x86
LX_ARCH   = x86
else
ifeq ($(ARCH),x86_64)
TOOL_ARCH = x86
LX_ARCH   = x86
else
$(error ARCH=$(ARCH) is not supported)
endif
endif
endif
endif
endif

# The following eager commands should only be evaluated when generating dummies
ifeq ($(COMMAND),generate)

ifeq ($(realpath $(LINUX_KERNEL_DIR)),)
$(error You have to state a valid LINUX_KERNEL_DIR, try help)
endif

ifeq ($(DUMMY_FILE),)
$(error You have to state a DUMMY_FILE, try help)
endif

endif # COMMAND=generate


#
# Prepare object database whenever LINUX_KERNEL_DIR is specified
#

ifneq ($(realpath $(LINUX_KERNEL_DIR)),)

# determine kernel source dir if an out-of-tree build directory is specified
LINUX_SRC_DIR := $(LINUX_KERNEL_DIR)
ifneq ($(shell grep "^\# Automatically generated by" $(LINUX_KERNEL_DIR)/Makefile),)
LINUX_SRC_DIR := $(shell sed -n "/^include/s/.* \(.*\)\/Makefile/\\1/p" $(LINUX_KERNEL_DIR)/Makefile)
endif

CROSS_DEV_PREFIX ?= /usr/local/genode/tool/current/bin/genode-$(TOOL_ARCH)-

# gather list of <path.c>:<symbol> pairs, strip first path element (build dir)
NM          = $(CROSS_DEV_PREFIX)nm --print-file-name --defined-only
C_FILE_DEF := $(shell cd $(LINUX_KERNEL_DIR); $(NM) `find -name "*.o" -printf "%P\n" | grep -v vmlinux.o` | grep -i " [tD] " | sed -e 's/o:[0-f]* [tTD] /c:/')

# query C_FILE_DEF database for a given symbol
symbol_to_c_file  = $(addprefix $(LINUX_SRC_DIR)/, $(firstword $(subst :, ,$(filter %:$(1),$(C_FILE_DEF)))))

#
# Ctags database
#

HEADER_DECL      := $(shell cd $(LINUX_SRC_DIR)/include; ctags -R -x --kinds-c=p --_xformat="%N:%F" .)
GLOBAL_VAR       := $(shell cd $(LINUX_SRC_DIR)/include; ctags -R -x --kinds-c=x --_xformat="%N:%F" .)
func_to_h_file    = $(lastword $(subst :, ,$(filter $(1):%,$(HEADER_DECL))))
do_func_to_def    = $(subst :, ,$(subst typename:,,$(subst $(1): ,,$(shell ctags -x --kinds-c=f --_xformat="%N: %t %N%S" $(2) | grep "^\<$(1)\>:"))))
check_func_to_def = $(if $(2),$(call do_func_to_def,$(1),$(2)),)
func_to_def       = $(call check_func_to_def,$(1),$(call symbol_to_c_file,$(1)))

var_to_h_file     = $(lastword $(subst :, ,$(filter $(1):%,$(GLOBAL_VAR))))
do_var_to_def     = $(subst ];,] = {};,$(subst \/,/,$(subst extern ,,$(subst $$/,,$(subst $(1): /^,,$(shell ctags -x --kinds-c=x --_xformat="%N: %P" $(LINUX_SRC_DIR)/include/$(2) | grep "^\<$(1)\>:"))))))
check_var_to_def  = $(if $(2),$(call do_var_to_def,$(1),$(2)),)
var_to_def        = $(call check_var_to_def,$(1),$(call var_to_h_file,$(1)))

endif # LINUX_KERNEL_DIR specified


#
# Collect undefined references for target
#
# use 'env - ' to reset environment, especially TARGET because it will be used by Genode's build sytem
# during linking later on and not point to the actual build TARGET (GNU Make 4.4+)
#
UNDEF_REFS := $(sort $(subst `,,$(subst ',,$(shell env - PATH=$(PATH) make -C $(BUILD_DIR) $(TARGET) 2>&1 | grep " undefined reference to " | sed -e "s/.* reference to //"))))

define print_file_header
echo "/*"                                                       > $(2);
echo " * \\brief  Dummy definitions of Linux Kernel functions" >> $(2);
echo " * \\author Automatically generated file - do no edit"   >> $(2);
echo " * \\date   $(1)"                                        >> $(2);
echo " */"                                                     >> $(2);
echo ""                                                        >> $(2);
echo "#include <lx_emul.h>"                                    >> $(2);
echo ""                                                        >> $(2);
endef

define print_var
echo ""                                    >> $(3);
echo "#include <$(1)>"                     >> $(3);
echo ""                                    >> $(3);
echo "$(2)"                                >> $(3);
echo ""                                    >> $(3);
endef

define print_func_only
echo ""                                    >> $(2);
echo "extern $(1);"                        >> $(2);
echo "$(1)"                                >> $(2);
echo "{"                                   >> $(2);
echo "	lx_emul_trace_and_stop(__func__);" >> $(2);
echo "}"                                   >> $(2);
echo ""                                    >> $(2);
endef

define print_func
echo ""                                    >> $(3);
echo "#include <$(1)>"                     >> $(3);
echo ""                                    >> $(3);
echo "$(2)"                                >> $(3);
echo "{"                                   >> $(3);
echo "	lx_emul_trace_and_stop(__func__);" >> $(3);
echo "}"                                   >> $(3);
echo ""                                    >> $(3);
endef

define print_error
echo "Cannot create dummy for symbol $(1), maybe a macro?!" >&2;
endef

check_vdef = $(if $(3),$(call print_var,$(2),$(3),$(DUMMY_FILE)),$(call print_error,$(1)))
check_var  = $(if $(2),$(call check_vdef,$(1),$(2),$(call var_to_def,$(1))),$(call print_error,$(1)))
check_not_func = $(call check_var,$(1),$(call var_to_h_file,$(1)))
check_fdef_only = $(if $(2),$(call print_func_only,$(2),$(DUMMY_FILE)),$(call check_not_func,$(1)))
check_fdef = $(if $(3),$(call print_func,$(2),$(3),$(DUMMY_FILE)),$(call check_not_func,$(1)))
check_func = $(if $(2),$(call check_fdef,$(1),$(2),$(call func_to_def,$(1))),$(call check_fdef_only,$(1),$(call func_to_def,$(1))))

ifeq ($(realpath $(LINUX_KERNEL_DIR)),)
show_symbol = "$1"
else
show_symbol = "$1 $(foreach F,$(call symbol_to_c_file,$1),(found at $(subst $(LINUX_SRC_DIR)/,,$(F:.c=.o))))"
endif

show:
	$(ECHO) "Missing symbols:"
	@$(foreach sym,$(UNDEF_REFS),echo $(call show_symbol,$(sym));)
	$(ECHO) "Total sum of missing symbols is $(words $(UNDEF_REFS))"

generate:
	@$(call print_file_header,$(shell date +"%F"),$(DUMMY_FILE))
	@$(foreach sym,$(UNDEF_REFS),$(call check_func,$(sym),$(call func_to_h_file,$(sym))))

.PHONY: generate show help

# COMMAND!=help
endif