we setup source objects, but we support more. This allows one 'Build' file to
carry a sources list for multiple build objects.
-a) Build framework makefiles
-----------------------------
+
+Build framework makefiles
+-------------------------
The build framework consists of 2 Makefiles:
'Makefile.build' file is the makefile used from the outside. It's
interface/usage is following:
- $ make -f tools/build/Makefile srctree=$(KSRC) dir=$(DIR) obj=$(OBJECT)
+ $ make -f tools/build/Makefile.build srctree=$(KSRC) dir=$(DIR) obj=$(OBJECT)
where:
which includes all compiled sources described in 'Build' makefiles.
-a) Build makefiles
-------------------
+
+Build makefiles
+---------------
The user supplies 'Build' makefiles that contains a objects list, and connects
the build to nested directories.
You can check the 'ex' example in 'tools/build/tests/ex' for more details.
-b) Rules
---------
+
+Makefile.include
+----------------
+
+The tools/build/Makefile.include makefile could be included
+via user makefiles to get usefull definitions.
+
+It defines following interface:
+
+ - build macro definition:
+ build := -f $(srctree)/tools/build/Makefile.build dir=. obj
+
+ to make it easier to invoke build like:
+ make $(build)=ex
+
+
+Rules
+-----
The build framework provides standard compilation rules to handle .S and .c
compilation.
It's possible to include special rule if needed (like we do for flex or bison
code generation).
-c) CFLAGS
----------
+
+CFLAGS
+------
It's possible to alter the standard object C flags in the following way:
This C flags changes has the scope of the Build makefile they are defined in.
-d) Dependencies
----------------
+Dependencies
+------------
For each built object file 'a.o' the '.a.cmd' is created and holds:
the dependencies and trigger a rebuild when necessary.
-e) Single rules
----------------
+Single rules
+------------
It's possible to build single object file by choice, like:
MAKEOVERRIDES=
export srctree OUTPUT CC LD CFLAGS V
-build := -f $(srctree)/tools/build/Makefile.build dir=. obj
+include $(srctree)/tools/build/Makefile.include
BPF_IN := $(OUTPUT)libbpf-in.o
LIB_FILE := $(addprefix $(OUTPUT),$(LIB_FILE))
PERF_IN := $(OUTPUT)perf-in.o
export srctree OUTPUT RM CC LD AR CFLAGS V BISON FLEX AWK
-build := -f $(srctree)/tools/build/Makefile.build dir=. obj
+include $(srctree)/tools/build/Makefile.include
$(PERF_IN): $(OUTPUT)PERF-VERSION-FILE $(OUTPUT)common-cmds.h FORCE
$(Q)$(MAKE) $(build)=perf