Make device tree pre-processing similar to U-boot/Linux
Following changes are done to make DT pre-processing similar to that of
U-boot/Linux kernel.
1. Creating seperate CPPFLAGS for DT preprocessing so that compiler
options specific to it can be accommodated.
e.g: "-undef" compiler option avoids replacing "linux" string(used in
device trees) with "1" as "linux" is a pre-defined macro in gnu99
standard.
2. Replace CPP with PP for DT pre-processing, as CPP in U-boot/Linux is
exported as "${CROSS_COMPILE}gcc -E" while in TF-A it is exported as
"${CROSS_COMPILE}cpp".
Change-Id: If4c61a249d51614d9f53ae30b602036d50c02349
Signed-off-by: Manish Pandey <manish.pandey2@arm.com>
diff --git a/Makefile b/Makefile
index ad1ba15..4e606a2 100644
--- a/Makefile
+++ b/Makefile
@@ -242,6 +242,7 @@
TF_LDFLAGS += $(TF_LDFLAGS_$(ARCH))
DTC_FLAGS += -I dts -O dtb
+DTC_CPPFLAGS += -nostdinc -Iinclude -undef -x assembler-with-cpp
################################################################################
# Common sources and include directories
diff --git a/make_helpers/build_macros.mk b/make_helpers/build_macros.mk
index 961cabf..73b84c3 100644
--- a/make_helpers/build_macros.mk
+++ b/make_helpers/build_macros.mk
@@ -464,7 +464,7 @@
$(DOBJ): $(2) $(filter-out %.d,$(MAKEFILE_LIST)) | fdt_dirs
$${ECHO} " CPP $$<"
$(eval DTBS := $(addprefix $(1)/,$(call SOURCES_TO_DTBS,$(2))))
- $$(Q)$$(CPP) $$(CPPFLAGS) -x assembler-with-cpp -MT $(DTBS) -MMD -MF $(DTSDEP) -o $(DPRE) $$<
+ $$(Q)$$(PP) $$(DTC_CPPFLAGS) -MT $(DTBS) -MMD -MF $(DTSDEP) -o $(DPRE) $$<
$${ECHO} " DTC $$<"
$$(Q)$$(DTC) $$(DTC_FLAGS) -i fdts -d $(DTBDEP) -o $$@ $(DPRE)