在内核源代码树上使用 flycheck/flymake

Question

是否有一种简单/自动化的方式来配置 flycheck 或 flymake 在写入文件时显示错误注释 在linux内核源代码树中？假设我正在工作 fs/proc/cmdline.c 我想让flycheck下去 两个目录并执行“make fs/proc/cmdline.o”和 然后注释结果。假设 ARCH 和 CROSS_COMPILE 是在外部设置的。

Answer 1

我一直在考虑自己做这件事 - 这就是我所拥有的：

您需要找到内核源代码树的基础，因此默认的flymake 寻找Makefile 的交易适得其反。我们将添加我们自己的文件，该文件可用于定位源代码库，并用于包装正常的内核 makefile：

在内核源代码树的基础上添加一个文件flymake.mk（根据您自己的交叉编译需要进行配置）：

ARCH=mips
CROSS_COMPILE=mips-linux-gnu-

export ARCH
export CROSS_COMPILE

.PHONY: check-syntax
check-syntax:
    make -f Makefile $(patsubst %_flymake.o,%.o,$(patsubst %.c,%.o,$(CHK_SOURCES)))

要点是去掉“_flymake.c”，只编译真正的文件，真正地构建文件，而不仅仅是语法。这样可以避免我们意外创建file_flymake.o

我们需要说服 flymake 寻找 flymake.mk 并针对它运行 check-syntax - 将这些添加到您的 .emacs 中：

;; Build a custom command-line using flymake.mk
(defun flymake-get-kernel-make-cmdline (source base-dir)
  (list "make"
    (list "-s"
              "-f"
              "flymake.mk"
          "-C"
          base-dir
          (concat "CHK_SOURCES=" source)
          "SYNTAX_CHECK_MODE=1"
          "check-syntax")))

;; Search for flymake.mk to locate kernel tree base
(defun flymake-kernel-make-init ()
  (flymake-simple-make-init-impl 'flymake-create-temp-inplace t t "flymake.mk" 'flymake-get-kernel-make-cmdline))

;; Register against .c files under /linux/ or /kernel/
;; Since the list is parsed in order use `push`
(push '(".+/\\(linux\\|kernel\\)/.+\\.c$" flymake-kernel-make-init) flymake-allowed-file-name-masks)

限制：

• 无法解析头文件
• 无法解析 flymake 临时文件source_flymake.c（请确保忽略 flymake 标记，直到它运行过保存的文件）。我有一个按键可以强制重新运行 flymake。
• 外部模块不支持 flymake
• 需要预先注册路径匹配器（请参阅上面的 push 行）- 我对 flymake 的了解不够，无法让它一次性覆盖单个缓冲区。

可以通过修补内核 Makefile 本身来克服标头、临时和外部模块的限制，目前我想避免这种情况。

Answer 2

类似于 Gregs flymake sn-p 这是我想出的一种用于 flycheck 的方法：

(defun utils/flycheck-search-linux-makefile ()
  "Search for linux top `Makefile' "
  (labels
      ((find-makefile-file-r (path)
        (let* ((parent (file-name-directory path))
               (file (concat parent "Makefile")))
          (cond
           ((file-exists-p file)
            (progn
              (with-temp-buffer
                (insert-file-contents file)
                (if (string-match "VERSION = [0-9]+[[:space:]]*PATCHLEVEL" (buffer-string))
                    (throw 'found-it parent)
                  (find-makefile-file-r (directory-file-name parent))
                  ))))
           ((equal path parent) (throw 'found-it nil))
           (t (find-makefile-file-r (directory-file-name parent)))))))
    (if (buffer-file-name)
        (catch 'found-it
          (find-makefile-file-r (buffer-file-name)))
      (error "buffer is not visiting a file"))))

(flycheck-define-checker utils/flycheck-linux-makefile-checker
  "Linux source checker"
  :command
  (
   "make" "C=1" "-C" (eval (utils/flycheck-search-linux-makefile))
   (eval (concat (file-name-sans-extension (file-relative-name buffer-file-name (utils/flycheck-search-linux-makefile))) ".o"))
   )
  :error-patterns
  ((error line-start
          (message "In file included from") " " (file-name) ":" line ":"
          column ":"
      line-end)
   (info line-start (file-name) ":" line ":" column
         ": note: " (message) line-end)
   (warning line-start (file-name) ":" line ":" column
            ": warning: " (message) line-end)
   (error line-start (file-name) ":" line ":" column
          ": " (or "fatal error" "error") ": " (message) line-end))
  :error-filter
  (lambda (errors)
    (let ((errors (flycheck-sanitize-errors errors)))
      (dolist (err errors)
        (let* ((fn (flycheck-error-filename err))
               (rn0 (file-relative-name fn default-directory)) ; flycheck-fix-error-filename converted to absolute, revert                                                                                  
               (rn1 (expand-file-name rn0 (utils/flycheck-search-linux-makefile))) ; make absolute relative to "make -C dir"                                                                                
               (ef (file-relative-name rn1 default-directory)) ; relative to source                                                                                                                         
               )
          (setf (flycheck-error-filename err) ef)
          )))
    errors)
  :modes (c-mode c++-mode)
  )

(defun utils/flycheck-mode-hook ()
  "Flycheck mode hook."
  (make-variable-buffer-local 'flycheck-linux-makefile)
  (setq flycheck-linux-makefile (utils/flycheck-search-linux-makefile))
  (if flycheck-linux-makefile
      (flycheck-select-checker 'utils/flycheck-linux-makefile-checker))
  )

(add-hook 'flycheck-mode-hook 'utils/flycheck-mode-hook)

• utils/flycheck-search-linux-makefile ：这将搜索包含 VERSION = .. PATCHLEVEL = ... 的顶级 linux Makefile
• utils/flycheck-linux-makefile-checker ：flycheck 检查器，它使用需要安装 sparse 的“make”“C=1”“-c”“...”

不完美但可用。

Answer 3

我正在使用 flymake.mk 之类的生成文件

## case 2: called within docker and cross env
ifeq (${_FLYMAKE_WRAPPED},)

_c_sources := $(filter %.c,$(CHK_SOURCES))
_h_sources := $(filter %.h,$(CHK_SOURCES))

_make_wrapped = $(MAKE) \
        kbuild-file=$(abspath $(firstword ${MAKEFILE_LIST})) \
        _FLYMAKE_WRAPPED=$1 _FLYMAKE_TYPE=$2 M=$(dir $*) $3

check-syntax:   $(addprefix .check-syntax_,${_c_sources} ${_h_sources})

$(addprefix .check-syntax_,${_c_sources} ${_h_sources}):.check-syntax_%:
        +$(call _make_wrapped,2,c)

## case 3: checking the files
else ifeq (${_FLYMAKE_WRAPPED},2)

-include $(dir ${CHK_SOURCES})/Makefile
-include $(dir ${CHK_SOURCES})/Kbuild

# Reset object/module list
obj-y :=
obj-m :=
lib-y :=
lib-m :=
always :=
targets :=
subdir-y :=
subdir-m :=

__build: check-syntax
.PHONY: check-syntax

clean_checkflags = $(filter-out -M% -g% -Wp,-M%,$1)

check-syntax: ${CHK_SOURCES}
        $(CC) $(call clean_checkflags,$(c_flags)) -c -o /dev/null -S $<

endif

它既适用于头文件，也适用于临时 flymake 文件。