tools build: Add new build support

Adding new build framework into 'tools/build' to be used by tools.

There's no change for actual building at this point, it comes in the
next patches.

The idea and more details are explained in the
'tools/build/Documentation/Build.txt' file.

I adopted everything from the kernel build system, with some changes to
allow for multiple binaries build definitions.

While the kernel's build output is single image (forget modules) we need
to be able to build several binaries/libraries.

The basic idea is that sser provides 'Build' files with objects
definitions like:

  perf-y += a.o
  perf-y += b.o
  libperf-y += c.o
  libperf-y += d.o

and the build framework outputs files:

  perf-in.o    # a.o, b.o compiled in
  libperf-in.o # c.o, d.o compiled in

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Tested-by: Will Deacon <will.deacon@arm.com>
Cc: Alexis Berlemont <alexis.berlemont@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-fbj22h4av0otlxupwcmrxgpa@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 81 insertions, 0 deletions

diff --git a/tools/build/Build.include b/tools/build/Build.include
new file mode 100644
index 0000000000000..4c8daaccb82a9
--- /dev/null
+++ b/tools/build/Build.include
@@ -0,0 +1,81 @@
+###
+# build: Generic definitions
+#
+#  Lots of this code have been borrowed or heavily inspired from parts
+#  of kbuild code, which is not credited, but mostly developed by:
+#
+#  Copyright (C) Sam Ravnborg <sam@mars.ravnborg.org>, 2015
+#  Copyright (C) Linus Torvalds <torvalds@linux-foundation.org>, 2015
+#
+
+###
+# Convenient variables
+comma   := ,
+squote  := '
+
+###
+# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
+dot-target = $(dir $@).$(notdir $@)
+
+###
+# filename of target with directory and extension stripped
+basetarget = $(basename $(notdir $@))
+
+###
+# The temporary file to save gcc -MD generated dependencies must not
+# contain a comma
+depfile = $(subst $(comma),_,$(dot-target).d)
+
+###
+# Check if both arguments has same arguments. Result is empty string if equal.
+arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
+                    $(filter-out $(cmd_$@),   $(cmd_$(1))) )
+
+###
+# Escape single quote for use in echo statements
+escsq = $(subst $(squote),'\$(squote)',$1)
+
+# Echo command
+# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
+echo-cmd = $(if $($(quiet)cmd_$(1)),\
+           echo '  $(call escsq,$($(quiet)cmd_$(1)))';)
+
+###
+# Replace >$< with >$$< to preserve $ when reloading the .cmd file
+# (needed for make)
+# Replace >#< with >\#< to avoid starting a comment in the .cmd file
+# (needed for make)
+# Replace >'< with >'\''< to be able to enclose the whole string in '...'
+# (needed for the shell)
+make-cmd = $(call escsq,$(subst \#,\\\#,$(subst $$,$$$$,$(cmd_$(1)))))
+
+###
+# Find any prerequisites that is newer than target or that does not exist.
+# PHONY targets skipped in both cases.
+any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
+
+###
+# if_changed_dep  - execute command if any prerequisite is newer than
+#                   target, or command line has changed and update
+#                   dependencies in the cmd file
+if_changed_dep = $(if $(strip $(any-prereq) $(arg-check)),         \
+	@set -e;                                                   \
+	$(echo-cmd) $(cmd_$(1));                                   \
+	cat $(depfile) > $(dot-target).cmd;                        \
+	printf '%s\n' 'cmd_$@ := $(make-cmd)' >> $(dot-target).cmd)
+
+# if_changed      - execute command if any prerequisite is newer than
+#                   target, or command line has changed
+if_changed = $(if $(strip $(any-prereq) $(arg-check)),             \
+	@set -e;                                                   \
+	$(echo-cmd) $(cmd_$(1));                                   \
+	printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)
+
+###
+# C flags to be used in rule definitions, includes:
+# - depfile generation
+# - global $(CFLAGS)
+# - per target C flags
+# - per object C flags
+# - BUILD_STR macro to allow '-D"$(variable)"' constructs
+c_flags = -Wp,-MD,$(depfile),-MT,$@ $(CFLAGS) -D"BUILD_STR(s)=\#s" $(CFLAGS_$(basetarget).o) $(CFLAGS_$(obj))