kbuild: Add support to generate LLVM assembly files

Add rules to kbuild in order to generate LLVM assembly files with the .ll
extension when using clang.

  # from c code
  make CC=clang kernel/pid.ll

Signed-off-by: Vinícius Tinti <viniciustinti@gmail.com>
Signed-off-by: Behan Webster <behanw@converseincode.com>
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/Makefile b/Makefile
index 88d607245791..439443176161 100644
--- a/Makefile
+++ b/Makefile
@@ -1373,6 +1373,8 @@ help:
 	@echo  '                    (default: $$(INSTALL_MOD_PATH)/lib/firmware)'
 	@echo  '  dir/            - Build all files in dir and below'
 	@echo  '  dir/file.[ois]  - Build specified target only'
+	@echo  '  dir/file.ll     - Build the LLVM assembly file'
+	@echo  '                    (requires compiler support for LLVM assembly generation)'
 	@echo  '  dir/file.lst    - Build specified mixed source/assembly target only'
 	@echo  '                    (requires a recent binutils and recent build (System.map))'
 	@echo  '  dir/file.ko     - Build module including final link'
@@ -1557,6 +1559,7 @@ clean: $(clean-dirs)
 		-o -name '*.symtypes' -o -name 'modules.order' \
 		-o -name modules.builtin -o -name '.tmp_*.o.*' \
 		-o -name '*.c.[012]*.*' \
+		-o -name '*.ll' \
 		-o -name '*.gcno' \) -type f -print | xargs rm -f
 
 # Generate tags for editors
@@ -1660,6 +1663,8 @@ endif
 	$(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
 %.symtypes: %.c prepare scripts FORCE
 	$(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
+%.ll: %.c prepare scripts FORCE
+	$(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
 
 # Modules
 /: prepare scripts FORCE