In the current compilation environment, the recursive assignment(=) for compile
flags will be delayed until every file is actually need to be compile.
For example:
--------------------------------------------------------------------------------
arch/arm/src/Makefile:
INCLUDES += ${shell $(INCDIR) "$(CC)" $(ARCH_SRCDIR)$(DELIM)chip}
INCLUDES += ${shell $(INCDIR) "$(CC)" $(ARCH_SRCDIR)$(DELIM)common}
INCLUDES += ${shell $(INCDIR) "$(CC)" $(ARCH_SRCDIR)$(DELIM)$(ARCH_SUBDIR)}
INCLUDES += ${shell $(INCDIR) "$(CC)" $(TOPDIR)$(DELIM)sched}
CPPFLAGS += $(INCLUDES) $(EXTRAFLAGS)
CFLAGS += $(INCLUDES) $(EXTRAFLAGS)
CXXFLAGS += $(INCLUDES) $(EXTRAFLAGS)
AFLAGS += $(INCLUDES) $(EXTRAFLAGS)
--------------------------------------------------------------------------------
All compilation options will be included recursively,
which will be delayed until the compilation options are actually used:
tools/Config.mk:
--------------------------------------------------------------------------------
define COMPILE
@echo "CC: $1"
$(Q) $(CC) -c $(CFLAGS) $($(strip $1)_CFLAGS) $1 -o $2
endef
--------------------------------------------------------------------------------
All compile flags to be reexecuted $(INCDIR) as long as one file needs to be compiled,
but in fact, the compilation options have not changed in the current directory.
So the we recommand to change the syntax of assignment
From
Recursive (=)
To
Simple (:=)
In this way, we can ensure that all compilation options are expanded only once and reducing repeated works.
Signed-off-by: chao.an <anchao@xiaomi.com>
1.It make sense to let Toolchain.defs give the default value
2.The board can still change if the default isn't suitable
3.Avoid the same definition spread more than 200 Make.defs
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Change-Id: Ic2649f1c7689bcf59c105ca8db61cad45b6e0e64
Make.defs under board folder can still overwrite the default as needed
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Change-Id: I1c300a8ace4b54d475ef8d398661ed65ca273a2e
so all boards support uClibc++/libc++ automatically
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Change-Id: Ibe6fafbec57f7acb26ea6188a3e9923ea82295c5
