Makefile: Replace flag -DX with -DX= to be supported by IS_ENABLED().

IS_ENABLED works for an empty-string-defined macro.
However, -D options default to define the macro to 1.  This CL forces
those macros, such as BOARD_* CHIP_*, CORE_*, CHIP_VARIANT_* and
CHIP_FAMILIY_*, to be defined as an empty string, so that it can
be supported by IS_ENABLED macro.

TEST=use if(IS_ENABLED(BOARD_KRANE)) and see compilation success.
TEST=compares build directory w/ and w/o this CL, and see the .smap
     are the same:
     ls build/*/*/ec.*.smap | sed -e 's|build/||' | \
     xargs -I{} diff -u -a build/{} build.new/{}
BUG=none
BRANCH=None

Change-Id: I96e2aa1cb5f3369e5e445a674595a9234f26707a
Signed-off-by: Yilun Lin <yllin@google.com>
Reviewed-on: https://chromium-review.googlesource.com/1627840
Commit-Ready: Yilun Lin <yllin@chromium.org>
Tested-by: Yilun Lin <yllin@chromium.org>
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
Reviewed-by: Jett Rink <jettrink@chromium.org>
Reviewed-by: Jack Rosenthal <jrosenth@chromium.org>
Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>

1 files changed, 21 insertions, 16 deletions

diff --git a/Makefile b/Makefile
index 354c0bf14a..3ccef58b91 100644
--- a/Makefile
+++ b/Makefile
@@ -41,6 +41,11 @@ endif
 
 PROJECT?=ec
 
+# An empty string.
+# "-DMACRO" leads to MACRO=1.  Define an empty string "-DMACRO=" to take
+# advantage of IS_ENABLED magic macro, which only allows an empty string.
+EMPTY=
+
 # Output directory for build objects
 ifdef CTS_MODULE
 # CTS builds need different directories per board per suite.
@@ -98,7 +103,7 @@ endif
 # Baseboard directory
 ifneq (,$(BASEBOARD))
 BASEDIR:=baseboard/$(BASEBOARD)
-CFLAGS_BASEBOARD=-DHAS_BASEBOARD -DBASEBOARD_$(UC_BASEBOARD)
+CFLAGS_BASEBOARD=-DHAS_BASEBOARD=$(EMPTY) -DBASEBOARD_$(UC_BASEBOARD)=$(EMPTY)
 include $(BASEDIR)/build.mk
 else
 # If BASEBOARD is not defined, then assign BASEDIR to BDIR. This avoids
@@ -130,8 +135,8 @@ includes+=cts/$(CTS_MODULE) cts
 endif
 ifeq "$(TEST_BUILD)" "y"
 	_tsk_lst_file:=ec.tasklist
-	_tsk_lst_flags:=$(if $(TEST_FUZZ),-Ifuzz,-Itest) -DTEST_BUILD -imacros \
-			$(PROJECT).tasklist
+	_tsk_lst_flags:=$(if $(TEST_FUZZ),-Ifuzz,-Itest) -DTEST_BUILD=$(EMPTY) \
+			-imacros $(PROJECT).tasklist
 else ifdef CTS_MODULE
 	_tsk_lst_file:=ec.tasklist
 	_tsk_lst_flags:=-I cts/$(CTS_MODULE) -Icts -DCTS_MODULE=$(CTS_MODULE) \
@@ -141,13 +146,13 @@ else
 	_tsk_lst_flags:=
 endif
 
-_tsk_lst_flags+=-I$(BDIR) -DBOARD_$(UC_BOARD) -I$(BASEDIR) \
-		-DBASEBOARD_$(UC_BASEBOARD) -D_MAKEFILE \
-		-imacros $(_tsk_lst_file)
+_tsk_lst_flags+=-I$(BDIR) -DBOARD_$(UC_BOARD)=$(EMPTY) -I$(BASEDIR) \
+		-DBASEBOARD_$(UC_BASEBOARD)=$(EMPTY) \
+		-D_MAKEFILE=$(EMPTY) -imacros $(_tsk_lst_file)
 
-_tsk_lst_ro:=$(shell $(CPP) -P -DSECTION_IS_RO \
+_tsk_lst_ro:=$(shell $(CPP) -P -DSECTION_IS_RO=$(EMPTY) \
 	$(_tsk_lst_flags) include/task_filter.h)
-_tsk_lst_rw:=$(shell $(CPP) -P -DSECTION_IS_RW \
+_tsk_lst_rw:=$(shell $(CPP) -P -DSECTION_IS_RW=$(EMPTY) \
 	$(_tsk_lst_flags) include/task_filter.h)
 
 _tsk_cfg_ro:=$(foreach t,$(_tsk_lst_ro) ,HAS_TASK_$(t))
@@ -157,22 +162,22 @@ _tsk_cfg:= $(filter $(_tsk_cfg_ro), $(_tsk_cfg_rw))
 _tsk_cfg_ro:= $(filter-out $(_tsk_cfg), $(_tsk_cfg_ro))
 _tsk_cfg_rw:= $(filter-out $(_tsk_cfg), $(_tsk_cfg_rw))
 
-CPPFLAGS_RO+=$(foreach t,$(_tsk_cfg_ro),-D$(t)) \
-		$(foreach t,$(_tsk_cfg_rw),-D$(t)_RW)
-CPPFLAGS_RW+=$(foreach t,$(_tsk_cfg_rw),-D$(t)) \
-		$(foreach t,$(_tsk_cfg_ro),-D$(t)_RO)
-CPPFLAGS+=$(foreach t,$(_tsk_cfg),-D$(t))
+CPPFLAGS_RO+=$(foreach t,$(_tsk_cfg_ro),-D$(t)=$(EMPTY)) \
+		$(foreach t,$(_tsk_cfg_rw),-D$(t)_RW=$(EMPTY))
+CPPFLAGS_RW+=$(foreach t,$(_tsk_cfg_rw),-D$(t)=$(EMPTY)) \
+		$(foreach t,$(_tsk_cfg_ro),-D$(t)_RO=$(EMPTY))
+CPPFLAGS+=$(foreach t,$(_tsk_cfg),-D$(t)=$(EMPTY))
 ifneq ($(ENV_VARS),)
-CPPFLAGS += -DINCLUDE_ENV_CONFIG
+CPPFLAGS += -DINCLUDE_ENV_CONFIG=$(EMPTY)
 CFLAGS += -I$(realpath $(out))
 endif
 # Get the CONFIG_ and VARIANT_ options that are defined for this target and make
 # them into variables available to this build script
 _flag_cfg_ro:=$(shell $(CPP) $(CPPFLAGS) -P -dM -Ichip/$(CHIP) \
-	-I$(BASEDIR) -I$(BDIR) -DSECTION_IS_RO include/config.h | \
+	-I$(BASEDIR) -I$(BDIR) -DSECTION_IS_RO=$(EMPTY) include/config.h | \
 	grep -o "\#define \(CONFIG\|VARIANT\)_[A-Z0-9_]*" | cut -c9- | sort)
 _flag_cfg_rw:=$(_tsk_cfg_rw) $(shell $(CPP) $(CPPFLAGS) -P -dM -Ichip/$(CHIP) \
-	-I$(BASEDIR) -I$(BDIR) -DSECTION_IS_RW include/config.h | \
+	-I$(BASEDIR) -I$(BDIR) -DSECTION_IS_RW=$(EMPTY) include/config.h | \
 	grep -o "\#define \(CONFIG\|VARIANT\)_[A-Z0-9_]*" | cut -c9- | sort)
 
 _flag_cfg:= $(filter $(_flag_cfg_ro), $(_flag_cfg_rw))