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2019-08-16gen_compile_commands: lower the entry count thresholdMasahiro Yamada1-2/+2
[ Upstream commit cb36955a5569f1ff17a42ae93264ef391c013a97 ] Running gen_compile_commands.py after building the kernel with allnoconfig gave this: $ ./scripts/gen_compile_commands.py WARNING: Found 449 entries. Have you compiled the kernel? Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2018-12-19scripts: add a tool to produce a compile_commands.json fileTom Roeder1-0/+151
The LLVM/Clang project provides many tools for analyzing C source code. Many of these tools are based on LibTooling (https://clang.llvm.org/docs/LibTooling.html), which depends on a database of compiler flags. The standard container for this database is compile_commands.json, which consists of a list of JSON objects, each with "directory", "file", and "command" fields. Some build systems, like cmake or bazel, produce this compilation information directly. Naturally, Makefiles don't. However, the kernel makefiles already create .<target>.o.cmd files that contain all the information needed to build a compile_commands.json file. So, this commit adds scripts/gen_compile_commands.py, which recursively searches through a directory for .<target>.o.cmd files and extracts appropriate compile commands from them. It writes a compile_commands.json file that LibTooling-based tools can use. By default, gen_compile_commands.py starts its search in its working directory and (over)writes compile_commands.json in the working directory. However, it also supports --output and --directory flags for out-of-tree use. Note that while gen_compile_commands.py enables the use of clang-based tools, it does not require the kernel to be compiled with clang. E.g., the following sequence of commands produces a compile_commands.json file that works correctly with LibTooling. make defconfig make scripts/gen_compile_commands.py Also note that this script is written to work correctly in both Python 2 and Python 3, so it does not specify the Python version in its first line. For an example of the utility of this script: after running gen_compile_commands.json on the latest kernel version, I was able to use Vim + the YouCompleteMe pluging + clangd to automatically jump to definitions and declarations. Obviously, cscope and ctags provide some of this functionality; the advantage of supporting LibTooling is that it opens the door to many other clang-based tools that understand the code directly and do not rely on regular expressions and heuristics. Tested: Built several recent kernel versions and ran the script against them, testing tools like clangd (for editor/LSP support) and clang-check (for static analysis). Also extracted some test .cmd files from a kernel build and wrote a test script to check that the script behaved correctly with all permutations of the --output and --directory flags. Signed-off-by: Tom Roeder <tmroeder@google.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>