[emacs] Add regexps for defuns

[luke]

Summary

Previously M-x mark-defun and friends wouldn't work properly, and would
highlight something at the top of the buffer. This adds a regexp for top-level
functions so the defun functions should work as expected, and also adds a
regexp for extracting their name so which-function-mode should work now too.

[goldstein.w.n]

llvm/utils/emacs/llvm-mode.el

102

Slightly buggy.
Fails on something like:

define i1 @foo() {
  ret i1 true
}

You need .+ -> .* within the parens. I.e no variables is acceptable.

111

Likewise here.

[luke]

Handle functions with no arguments and trailing attributes (e.g. nounwind)

[luke]

llvm/utils/emacs/llvm-mode.el

111

Whoops. Also found we need to handle trailing attributes like nounwind etc., since defun-prompt-regexp needs to match right up to the first {

[goldstein.w.n]

llvm/utils/emacs/llvm-mode.el

111

Does this still need to be fixed. Don't see any codes for matching {.

[luke]

llvm/utils/emacs/llvm-mode.el

111

This is fixed, IIUC emacs automatically looks between top-level { braces for defuns, but by default they have to be in column 0. So defun-prompt-regexp skips over those characters so that { is then the first character, e.g. see the definition for bash: https://github.com/emacs-mirror/emacs/blob/7b30e11b2ac5cd360db7ee8b6aed07bd918b93a2/lisp/progmodes/sh-script.el#L1531C1-L1537

[goldstein.w.n]

Lgtm

llvm/utils/emacs/llvm-mode.el

(defvar llvm-font-lock-keywords
    ;; Atomic memory ordering constraints
    `(,(regexp-opt '("unordered" "monotonic" "acquire" "release" "acq_rel" "seq_cst") 'symbols) . font-lock-keyword-face)
    ;; Fast-math flags
    `(,(regexp-opt '("nnan" "ninf" "nsz" "arcp" "contract" "afn" "reassoc" "fast") 'symbols) . font-lock-keyword-face)
    ;; Use-list order directives
    `(,(regexp-opt '("uselistorder" "uselistorder_bb") 'symbols) . font-lock-keyword-face))
   "Syntax highlighting for LLVM.")
 
+(defun llvm-current-defun-name ()
+  "The `add-log-current-defun' function in LLVM mode."
+  (save-excursion
+    (end-of-line)
+    (if (re-search-backward "^[ \t]*define[ \t]+.+[ \t]+@\\(.+\\)(.*)" nil t)
+  (match-string-no-properties 1))))
+
 ;;;###autoload
 (define-derived-mode llvm-mode prog-mode "LLVM"
   "Major mode for editing LLVM source files.
 \\{llvm-mode-map}
   Runs `llvm-mode-hook' on startup."
   (setq font-lock-defaults `(llvm-font-lock-keywords))
+  (setq-local defun-prompt-regexp "^[ \t]*define[ \t]+.+[ \t]+@.+(.*).+")
+  (setq-local add-log-current-defun-function #'llvm-current-defun-name)
   (setq-local comment-start ";"))
 
 ;; Associate .ll files with llvm-mode
 ;;;###autoload
 (add-to-list 'auto-mode-alist (cons "\\.ll\\'" 'llvm-mode))
 
 (provide 'llvm-mode)
 
 ;;; llvm-mode.el ends here