Move build-stamp and generatic files to obj/main/$(TARGET)

This allows target level parallel builds, since now there are no
shared files between targets.

Fixes #3261

Makefile

@@ -274,9 +274,10 @@ TARGET_BIN      = $(BIN_DIR)/$(FORKNAME)_$(FC_VER)_$(TARGET)_$(BUILD_SUFFIX).bin
 TARGET_HEX      = $(BIN_DIR)/$(FORKNAME)_$(FC_VER)_$(TARGET)_$(BUILD_SUFFIX).hex
 endif
 
+TARGET_OBJ_DIR  = $(OBJECT_DIR)/$(TARGET)
 TARGET_ELF      = $(OBJECT_DIR)/$(FORKNAME)_$(TARGET).elf
-TARGET_OBJS     = $(addsuffix .o,$(addprefix $(OBJECT_DIR)/$(TARGET)/,$(basename $(TARGET_SRC))))
-TARGET_DEPS     = $(addsuffix .d,$(addprefix $(OBJECT_DIR)/$(TARGET)/,$(basename $(TARGET_SRC))))
+TARGET_OBJS     = $(addsuffix .o,$(addprefix $(TARGET_OBJ_DIR)/,$(basename $(TARGET_SRC))))
+TARGET_DEPS     = $(addsuffix .d,$(addprefix $(TARGET_OBJ_DIR)/,$(basename $(TARGET_SRC))))
 TARGET_MAP      = $(OBJECT_DIR)/$(FORKNAME)_$(TARGET).map
 
 
@@ -285,28 +286,31 @@ CLEAN_ARTIFACTS += $(TARGET_HEX)
 CLEAN_ARTIFACTS += $(TARGET_ELF) $(TARGET_OBJS) $(TARGET_MAP)
 
 # Make sure build date and revision is updated on every incremental build
-$(OBJECT_DIR)/$(TARGET)/build/version.o : $(TARGET_SRC)
+$(TARGET_OBJ_DIR)/build/version.o : $(TARGET_SRC)
 
 # Settings generator
 .PHONY: .FORCE settings clean-settings
-UTILS_DIR		= $(ROOT)/src/utils
-SETTINGS_GENERATOR	= $(UTILS_DIR)/settings.rb
-BUILD_STAMP		= $(UTILS_DIR)/build_stamp.rb
-STAMP			= $(BIN_DIR)/build.stamp
-
-GENERATED_SETTINGS	= $(SRC_DIR)/fc/settings_generated.h $(SRC_DIR)/fc/settings_generated.c
-SETTINGS_FILE 		= $(SRC_DIR)/fc/settings.yaml
-GENERATED_FILES		= $(GENERATED_SETTINGS)
+UTILS_DIR               = $(ROOT)/src/utils
+SETTINGS_GENERATOR      = $(UTILS_DIR)/settings.rb
+BUILD_STAMP             = $(UTILS_DIR)/build_stamp.rb
+STAMP                   = $(TARGET_OBJ_DIR)/build.stamp
+
+GENERATED_SETTINGS      = $(TARGET_OBJ_DIR)/settings_generated.h $(TARGET_OBJ_DIR)/settings_generated.c
+SETTINGS_FILE           = $(SRC_DIR)/fc/settings.yaml
+GENERATED_FILES         = $(GENERATED_SETTINGS)
 $(GENERATED_SETTINGS): $(SETTINGS_GENERATOR) $(SETTINGS_FILE) $(STAMP)
 
+# Make sure the generated files are in the include path
+CFLAGS                  += -I$(TARGET_OBJ_DIR)
+
 $(STAMP): .FORCE
 	$(V1) CFLAGS="$(CFLAGS)" TARGET=$(TARGET) ruby $(BUILD_STAMP) $(SETTINGS_FILE) $(STAMP)
 
 # Use a pattern rule, since they're different than normal rules.
 # See https://www.gnu.org/software/make/manual/make.html#Pattern-Examples
 %generated.h %generated.c:
 	$(V1) echo "settings.yaml -> settings_generated.h, settings_generated.c" "$(STDOUT)"
-	$(V1) CFLAGS="$(CFLAGS)" TARGET=$(TARGET) ruby $(SETTINGS_GENERATOR) . $(SETTINGS_FILE)
+	$(V1) CFLAGS="$(CFLAGS)" TARGET=$(TARGET) ruby $(SETTINGS_GENERATOR) . $(SETTINGS_FILE) -o $(TARGET_OBJ_DIR)
 
 settings-json:
 	$(V0) CFLAGS="$(CFLAGS)" TARGET=$(TARGET) ruby $(SETTINGS_GENERATOR) . $(SETTINGS_FILE) --json settings.json
@@ -329,18 +333,18 @@ $(TARGET_ELF): $(TARGET_OBJS)
 	$(V0) $(SIZE) $(TARGET_ELF)
 
 # Compile
-$(OBJECT_DIR)/$(TARGET)/%.o: %.c
+$(TARGET_OBJ_DIR)/%.o: %.c
 	$(V1) mkdir -p $(dir $@)
 	$(V1) echo %% $(notdir $<) "$(STDOUT)"
 	$(V1) $(CROSS_CC) -c -o $@ $(CFLAGS) $<
 
 # Assemble
-$(OBJECT_DIR)/$(TARGET)/%.o: %.s
+$(TARGET_OBJ_DIR)/%.o: %.s
 	$(V1) mkdir -p $(dir $@)
 	$(V1) echo %% $(notdir $<) "$(STDOUT)"
 	$(V1) $(CROSS_CC) -c -o $@ $(ASFLAGS) $<
 
-$(OBJECT_DIR)/$(TARGET)/%.o: %.S
+$(TARGET_OBJ_DIR)/%.o: %.S
 	$(V1) mkdir -p $(dir $@)
 	$(V1) echo %% $(notdir $<) "$(STDOUT)"
 	$(V1) $(CROSS_CC) -c -o $@ $(ASFLAGS) $<
@@ -377,8 +381,7 @@ $(VALID_TARGETS):
 clean:
 	$(V0) echo "Cleaning $(TARGET)"
 	$(V0) rm -f $(CLEAN_ARTIFACTS)
-	$(V0) rm -rf $(OBJECT_DIR)/$(TARGET)
-	$(V0) rm -f $(GENERATED_SETTINGS)
+	$(V0) rm -rf $(TARGET_OBJ_DIR)
 	$(V0) echo "Cleaning $(TARGET) succeeded."
 
 ## clean_test        : clean up all temporary / machine-generated files (tests)

src/main/fc/settings.c

@@ -4,10 +4,11 @@
 #include "common/string_light.h"
 #include "common/utils.h"
 
-#include "fc/settings_generated.h"
+#include "settings_generated.h"
+
 #include "fc/settings.h"
 
-#include "fc/settings_generated.c"
+#include "settings_generated.c"
 
 void setting_get_name(const setting_t *val, char *buf)
 {

src/main/fc/settings.h

@@ -6,7 +6,7 @@
 
 #include "config/parameter_group.h"
 
-#include "fc/settings_generated.h"
+#include "settings_generated.h"
 
 typedef struct lookupTableEntry_s {
     const char * const *values;

src/utils/build_stamp.rb

@@ -65,7 +65,9 @@ def hash_config
         output = File.join(@stamp_dir, "stamp")
         stdout, stderr = @compiler.run(input, output, ["-dM", "-E"])
         File.delete(input)
-        File.delete(output)
+        if File.file?(output)
+            File.delete(output)
+        end
         return Digest::SHA1.hexdigest(stdout)
     end
 end

src/utils/compiler.rb

@@ -80,7 +80,10 @@ def run(input, output, args = nil, options = { noerror: false })
         if args
             all_args.push(*args)
         end
-        all_args << "-o" << output << input
+        if output
+            all_args << "-o" << output
+        end
+        all_args << input
         stdout, stderr, compile_status = Open3.capture3(join_args(all_args))
 	raise "Compiler error:\n#{all_args.join(' ')}\n#{stderr}" if not options[:noerror] and not compile_status.success?
         return stdout, stderr

src/utils/settings.rb

@@ -260,10 +260,10 @@ def encode_value(buf, val)
 OFF_ON_TABLE = Hash["name" => "off_on", "values" => ["OFF", "ON"]]
 
 class Generator
-    def initialize(src_root, settings_file)
+    def initialize(src_root, settings_file, output_dir)
         @src_root = src_root
         @settings_file = settings_file
-        @output_dir = File.dirname(settings_file)
+        @output_dir = output_dir || File.dirname(settings_file)
 
         @compiler = Compiler.new
 
@@ -416,7 +416,7 @@ def write_impl_file(file)
         }
         add_header.call("platform.h")
         add_header.call("config/parameter_group_ids.h")
-        add_header.call("settings.h")
+        add_header.call("fc/settings.h")
 
         foreach_enabled_group do |group|
             (group["headers"] || []).each do |h|
@@ -623,10 +623,12 @@ def mktmpdir
         # Use a temporary dir reachable by relative path
         # since g++ in cygwin fails to open files
         # with absolute paths
-        tmp = File.join("obj", "tmp")
+        tmp = File.join(@output_dir, "tmp")
         FileUtils.mkdir_p(tmp) unless File.directory?(tmp)
         value = yield(tmp)
-        FileUtils.remove_dir(tmp)
+        if File.directory?(tmp)
+            FileUtils.remove_dir(tmp)
+        end
         value
     end
 
@@ -882,17 +884,20 @@ def usage
         exit(1)
     end
 
-    gen = Generator.new(src_root, settings_file)
 
     opts = GetoptLong.new(
+        [ "--output-dir", "-o", GetoptLong::REQUIRED_ARGUMENT ],
         [ "--help", "-h", GetoptLong::NO_ARGUMENT ],
         [ "--json", "-j", GetoptLong::REQUIRED_ARGUMENT ],
     )
 
     jsonFile = nil
+    output_dir = nil
 
     opts.each do |opt, arg|
         case opt
+        when "--output-dir"
+            output_dir = arg
         when "--help"
             usage()
             exit(0)
@@ -901,6 +906,8 @@ def usage
         end
     end
 
+    gen = Generator.new(src_root, settings_file, output_dir)
+
     if jsonFile
         gen.write_json(jsonFile)
     else