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author | Masahiro Yamada <masahiroy@kernel.org> | 2020-08-22 23:56:16 +0900 |
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committer | Masahiro Yamada <masahiroy@kernel.org> | 2020-08-27 00:44:33 +0900 |
commit | 3d32285fa99598f1885ac7022785b9c343407e62 (patch) | |
tree | 542ebca9df842df65d276836286d80a1f4cf7ff1 | |
parent | ecca4fea1ede446e9ce3afa0b68b07fd1550f4f5 (diff) | |
download | linux-3d32285fa99598f1885ac7022785b9c343407e62.tar.bz2 |
kbuild: wire up the build rule of compile_commands.json to Makefile
Currently, you need to manually run scripts/gen_compile_commands.py
to create compile_commands.json. It parses all the .*.cmd files found
under the specified directory.
If you rebuild the kernel over again without 'make clean',
.*.cmd files from older builds will create stale entries in
compile_commands.json.
This commit wires up the compile_commands.json rule to Makefile, and
makes it parse only the .*.cmd files involved in the current build.
Pass $(KBUILD_VMLINUX_OBJS), $(KBUILD_VMLINUX_LIBS), and modules.order
to the script. The objects or archives linked to vmlinux are listed in
$(KBUILD_VMLINUX_OBJS) or $(KBUILD_VMLINUX_LIBS). All the modules are
listed in modules.order.
You can create compile_commands.json from Make:
$ make -j$(nproc) CC=clang compile_commands.json
You can also build vmlinux, modules, and compile_commands.json all
together in a single command:
$ make -j$(nproc) CC=clang all compile_commands.json
It works for M= builds as well. In this case, compile_commands.json
is created in the top directory of the external module.
This is convenient, but it has a drawback; the coverage of the
compile_commands.json is reduced because only the objects linked to
vmlinux or modules are handled. For example, the following C files are
not included in the compile_commands.json:
- Decompressor source files (arch/*/boot/)
- VDSO source files
- C files used to generate intermediates (e.g. kernel/bounds.c)
- Standalone host programs
I think it is fine for most developers because our main interest is
the kernel-space code.
If you want to cover all the compiled C files, please build the kernel,
then run the script manually as you did before:
$ make clean # if you want to remove stale .cmd files [optional]
$ make -j$(nproc) CC=clang
$ scripts/gen_compile_commands.py
Here is a note for out-of-tree builds. 'make compile_commands.json'
works with O= option, but please notice compile_commands.json is
created in the object tree instead of the source tree.
Some people may want to have compile_commands.json in the source tree
because Clang Tools searches for it through all parent paths of the
first input source file.
However, you cannot do this for O= builds. Kbuild should never generate
any build artifact in the source tree when O= is given because the
source tree might be read-only. Any write attempt to the source tree
is monitored and the violation may be reported. See the commit log of
8ef14c2c41d9.
So, the only possible way is to create compile_commands.json in the
object tree, then specify '-p <build-path>' when you use clang-check,
clang-tidy, etc.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
-rw-r--r-- | Makefile | 29 |
1 files changed, 25 insertions, 4 deletions
@@ -634,7 +634,7 @@ endif # in addition to whatever we do anyway. # Just "make" or "make all" shall build modules as well -ifneq ($(filter all modules nsdeps,$(MAKECMDGOALS)),) +ifneq ($(filter all modules nsdeps %compile_commands.json,$(MAKECMDGOALS)),) KBUILD_MODULES := 1 endif @@ -1470,7 +1470,8 @@ endif # CONFIG_MODULES # Directories & files removed with 'make clean' CLEAN_FILES += include/ksym vmlinux.symvers \ - modules.builtin modules.builtin.modinfo modules.nsdeps + modules.builtin modules.builtin.modinfo modules.nsdeps \ + compile_commands.json # Directories & files removed with 'make mrproper' MRPROPER_FILES += include/config include/generated \ @@ -1704,9 +1705,12 @@ KBUILD_MODULES := 1 build-dirs := $(KBUILD_EXTMOD) PHONY += modules -modules: descend +modules: $(MODORDER) $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost +$(MODORDER): descend + @: + PHONY += modules_install modules_install: _emodinst_ _emodinst_post @@ -1720,8 +1724,12 @@ PHONY += _emodinst_post _emodinst_post: _emodinst_ $(call cmd,depmod) +compile_commands.json: $(extmod-prefix)compile_commands.json +PHONY += compile_commands.json + clean-dirs := $(KBUILD_EXTMOD) -clean: rm-files := $(KBUILD_EXTMOD)/Module.symvers $(KBUILD_EXTMOD)/modules.nsdeps +clean: rm-files := $(KBUILD_EXTMOD)/Module.symvers $(KBUILD_EXTMOD)/modules.nsdeps \ + $(KBUILD_EXTMOD)/compile_commands.json PHONY += help help: @@ -1834,6 +1842,19 @@ nsdeps: export KBUILD_NSDEPS=1 nsdeps: modules $(Q)$(CONFIG_SHELL) $(srctree)/scripts/nsdeps +# Clang Tooling +# --------------------------------------------------------------------------- + +quiet_cmd_gen_compile_commands = GEN $@ + cmd_gen_compile_commands = $(PYTHON3) $< -a $(AR) -o $@ $(filter-out $<, $(real-prereqs)) + +$(extmod-prefix)compile_commands.json: scripts/gen_compile_commands.py \ + $(if $(KBUILD_EXTMOD),,$(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS)) \ + $(if $(CONFIG_MODULES), $(MODORDER)) FORCE + $(call if_changed,gen_compile_commands) + +targets += $(extmod-prefix)compile_commands.json + # Scripts to check various things for consistency # --------------------------------------------------------------------------- |