From: Philippe Blain <levraiphilippeblain@xxxxxxxxx> Tools based on LibClang [1] can make use of a 'JSON Compilation Database' [2] that keeps track of the exact options used to compile a set of source files. The Clang compiler can generate JSON fragments when compiling [3], using the `-MJ` flag. These JSON fragments (one per compiled source file) can then be concatenated to create the compilation database, commonly called 'compile_commands.json'. Add support to the Makefile for generating these JSON fragments as well as the compilation database itself, if the environment variable 'GENERATE_COMPILATION_DATABASE' is set. If this variable is set, check that $(CC) indeed supports the `-MJ` flag, following what is done for automatic dependencies. All JSON fragments are placed in the 'compile_commands/' directory, and the compilation database 'compile_commands.json' is generated as a dependency of the 'all' target using a `sed` invocation. [1] https://clang.llvm.org/docs/Tooling.html [2] https://clang.llvm.org/docs/JSONCompilationDatabase.html [3] https://clang.llvm.org/docs/ClangCommandLineReference.html#cmdoption-clang-mj-arg Signed-off-by: Philippe Blain <levraiphilippeblain@xxxxxxxxx> --- Add support for generating JSON compilation database I don't have a lot of knowledge of Make double-colon rules, or insight into why they are used for the 'all' target, but I think the approach I chose makes sense. In particular, I do not list any prerequisite for the 'compile_commands.json' file, but from what I tested it is still rebuilt anytime the 'all' target is rebuilt, which is what we want. Note: CMakeLists.txt in contrib/buildsystems does not need to be updated to also support this feature because CMake supports it out-of-the-box [1]. [1] https://cmake.org/cmake/help/latest/variable/CMAKE_EXPORT_COMPILE_COMMANDS.html Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-714%2Fphil-blain%2Fcompiledb-v1 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-714/phil-blain/compiledb-v1 Pull-Request: https://github.com/gitgitgadget/git/pull/714 .gitignore | 2 ++ Makefile | 52 +++++++++++++++++++++++++++++++++++++++++++++++----- 2 files changed, 49 insertions(+), 5 deletions(-) diff --git a/.gitignore b/.gitignore index ee509a2ad2..f4c51300e0 100644 --- a/.gitignore +++ b/.gitignore @@ -197,6 +197,7 @@ /git.spec *.exe *.[aos] +*.o.json *.py[co] .depend/ *.gcda @@ -218,6 +219,7 @@ /tags /TAGS /cscope* +/compile_commands.json *.hcc *.obj *.lib diff --git a/Makefile b/Makefile index 65f8cfb236..954bd2aa47 100644 --- a/Makefile +++ b/Makefile @@ -462,6 +462,12 @@ all:: # the global variable _wpgmptr containing the absolute path of the current # executable (this is the case on Windows). # +# Define GENERATE_COMPILATION_DATABASE to generate JSON compilation database +# entries during compilation if your compiler supports it, using the `-MJ` flag. +# The JSON entries will be placed in the `compile_commands/` directory, +# and the JSON compilation database can be created afterwards with +# `make compile_commands.json`. +# # Define DEVELOPER to enable more compiler warnings. Compiler version # and family are auto detected, but could be overridden by defining # COMPILER_FEATURES (see config.mak.dev). You can still set @@ -1258,6 +1264,20 @@ $(error please set COMPUTE_HEADER_DEPENDENCIES to yes, no, or auto \ endif endif +ifdef GENERATE_COMPILATION_DATABASE +compdb_check = $(shell $(CC) $(ALL_CFLAGS) \ + -c -MJ /dev/null \ + -x c /dev/null -o /dev/null 2>&1; \ + echo $$?) +ifeq ($(compdb_check),0) +override GENERATE_COMPILATION_DATABASE = yes +else +override GENERATE_COMPILATION_DATABASE = no +$(warning GENERATE_COMPILATION_DATABASE is set, but your compiler does not \ +support generating compilation database entries) +endif +endif + ifdef SANE_TOOL_PATH SANE_TOOL_PATH_SQ = $(subst ','\'',$(SANE_TOOL_PATH)) BROKEN_PATH_FIX = 's|^\# @@BROKEN_PATH_FIX@@$$|git_broken_path_fix "$(SANE_TOOL_PATH_SQ)"|' @@ -2381,16 +2401,30 @@ missing_dep_dirs = dep_args = endif +compdb_dir = compile_commands/ + +ifeq ($(GENERATE_COMPILATION_DATABASE),yes) +missing_compdb_dir = $(compdb_dir) +$(missing_compdb_dir): + @mkdir -p $@ + +compdb_file = $(compdb_dir)$(subst .-,,$(subst /,-,$(dir $@)))$(notdir $@).json +compdb_args = -MJ $(compdb_file) +else +missing_compdb_dir = +compdb_args = +endif + ASM_SRC := $(wildcard $(OBJECTS:o=S)) ASM_OBJ := $(ASM_SRC:S=o) C_OBJ := $(filter-out $(ASM_OBJ),$(OBJECTS)) .SUFFIXES: -$(C_OBJ): %.o: %.c GIT-CFLAGS $(missing_dep_dirs) - $(QUIET_CC)$(CC) -o $*.o -c $(dep_args) $(ALL_CFLAGS) $(EXTRA_CPPFLAGS) $< -$(ASM_OBJ): %.o: %.S GIT-CFLAGS $(missing_dep_dirs) - $(QUIET_CC)$(CC) -o $*.o -c $(dep_args) $(ALL_CFLAGS) $(EXTRA_CPPFLAGS) $< +$(C_OBJ): %.o: %.c GIT-CFLAGS $(missing_dep_dirs) $(missing_compdb_dir) + $(QUIET_CC)$(CC) -o $*.o -c $(dep_args) $(compdb_args) $(ALL_CFLAGS) $(EXTRA_CPPFLAGS) $< +$(ASM_OBJ): %.o: %.S GIT-CFLAGS $(missing_dep_dirs) $(missing_compdb_dir) + $(QUIET_CC)$(CC) -o $*.o -c $(dep_args) $(compdb_args) $(ALL_CFLAGS) $(EXTRA_CPPFLAGS) $< %.s: %.c GIT-CFLAGS FORCE $(QUIET_CC)$(CC) -o $@ -S $(ALL_CFLAGS) $(EXTRA_CPPFLAGS) $< @@ -2413,6 +2447,14 @@ else $(OBJECTS): $(LIB_H) $(GENERATED_H) endif +ifeq ($(GENERATE_COMPILATION_DATABASE),yes) +all:: compile_commands.json +compile_commands.json: + @$(RM) $@ + $(QUIET_GEN)sed -e '1s/^/[/' -e '$$s/,$$/]/' $(compdb_dir)*.o.json > $@+ + @if test -s $@+; then mv $@+ $@; else $(RM) $@+; fi +endif + exec-cmd.sp exec-cmd.s exec-cmd.o: GIT-PREFIX exec-cmd.sp exec-cmd.s exec-cmd.o: EXTRA_CPPFLAGS = \ '-DGIT_EXEC_PATH="$(gitexecdir_SQ)"' \ @@ -3117,7 +3159,7 @@ clean: profile-clean coverage-clean cocciclean $(RM) $(TEST_PROGRAMS) $(RM) $(FUZZ_PROGRAMS) $(RM) $(HCC) - $(RM) -r bin-wrappers $(dep_dirs) + $(RM) -r bin-wrappers $(dep_dirs) $(compdb_dir) compile_commands.json $(RM) -r po/build/ $(RM) *.pyc *.pyo */*.pyc */*.pyo $(GENERATED_H) $(ETAGS_TARGET) tags cscope* $(RM) -r $(GIT_TARNAME) .doc-tmp-dir base-commit: d9cd4331470f4d9d78677f12dc79063dab832f53 -- gitgitgadget
