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Normalise setq during macro-expansion

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Early normalisation of setq during macroexpand-all allows later
stages, cconv, byte-opt and codegen, to be simplified and duplicated
checks to be eliminated.

* lisp/emacs-lisp/macroexp.el (macroexp--expand-all):
Normalise all setq forms to a sequence of (setq VAR EXPR).
Emit warnings if necessary.
* lisp/emacs-lisp/cconv.el (cconv-convert, cconv-analyze-form):
* lisp/emacs-lisp/byte-opt.el (byte-optimize-form-code-walker):
* lisp/emacs-lisp/bytecomp.el (byte-compile-setq):
Simplify.
* test/lisp/emacs-lisp/bytecomp-tests.el: Adapt and add tests.
* test/lisp/emacs-lisp/bytecomp-resources/warn-variable-setq-nonvariable.el;
* test/lisp/emacs-lisp/bytecomp-resources/warn-variable-setq-odd.el:
New files.
This commit is contained in:
Mattias Engdegård 2022-06-03 20:31:10 +02:00
parent 175bc8e5a5
commit 6825e5686a
7 changed files with 100 additions and 74 deletions
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48
lisp/emacs-lisp/macroexp.el
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@ -369,6 +369,54 @@ Assumes the caller has bound `macroexpand-all-environment'."
(macroexp--all-forms body))
(cdr form))
form)))
(`(setq ,(and var (pred symbolp)
(pred (not booleanp)) (pred (not keywordp)))
,expr)
;; Fast path for the setq common case.
(let ((new-expr (macroexp--expand-all expr)))
(if (eq new-expr expr)
form
`(,fn ,var ,new-expr))))
(`(setq . ,args)
;; Normalise to a sequence of (setq SYM EXPR).
;; Malformed code is translated to code that signals an error
;; at run time.
(let ((nargs (length args)))
(if (/= (logand nargs 1) 0)
(macroexp-warn-and-return
"odd number of arguments in `setq' form"
`(signal 'wrong-number-of-arguments '(setq ,nargs))
nil 'compile-only fn)
(let ((assignments nil))
(while (consp (cdr-safe args))
(let* ((var (car args))
(expr (cadr args))
(new-expr (macroexp--expand-all expr))
(assignment
(if (and (symbolp var)
(not (booleanp var)) (not (keywordp var)))
`(,fn ,var ,new-expr)
(macroexp-warn-and-return
(format-message "attempt to set %s `%s'"
(if (symbolp var)
"constant"
"non-variable")
var)
(cond
((keywordp var)
;; Accept `(setq :a :a)' for compatibility.
`(if (eq ,var ,new-expr)
,var
(signal 'setting-constant (list ',var))))
((symbolp var)
`(signal 'setting-constant (list ',var)))
(t
`(signal 'wrong-type-argument
(list 'symbolp ',var))))
nil 'compile-only var))))
(push assignment assignments))
(setq args (cddr args)))
(cons 'progn (nreverse assignments))))))
(`(,(and fun `(lambda . ,_)) . ,args)
;; Embedded lambda in function position.
;; If the byte-optimizer is loaded, try to unfold this,