diff options
Diffstat (limited to 'lisp/emacs-lisp/cconv.el')
| -rw-r--r-- | lisp/emacs-lisp/cconv.el | 31 |
1 files changed, 23 insertions, 8 deletions
diff --git a/lisp/emacs-lisp/cconv.el b/lisp/emacs-lisp/cconv.el index 570c9e66060..b8121aeba55 100644 --- a/lisp/emacs-lisp/cconv.el +++ b/lisp/emacs-lisp/cconv.el @@ -113,6 +113,10 @@ is less than this number.") (defvar cconv--dynbound-variables nil "List of variables known to be dynamically bound.") +(defvar cconv-dont-trim-unused-variables nil + "When bound to non-nil, don't remove unused variables from the environment. +This is intended for use by edebug and similar.") + ;;;###autoload (defun cconv-closure-convert (form &optional dynbound-vars) "Main entry point for closure conversion. @@ -834,10 +838,13 @@ This function does not return anything but instead fills the (define-obsolete-function-alias 'cconv-analyse-form #'cconv-analyze-form "25.1") (defun cconv-fv (form lexvars dynvars) - "Return the list of free variables in FORM. -LEXVARS is the list of statically scoped vars in the context -and DYNVARS is the list of dynamically scoped vars in the context. -Returns a pair (LEXV . DYNV) of those vars actually used by FORM." + "Return the free variables used in FORM. +FORM is usually a function #\\='(lambda ...), but may be any valid +form. LEXVARS is a list of symbols, each of which is lexically +bound in FORM's context. DYNVARS is a list of symbols, each of +which is dynamically bound in FORM's context. +Returns a cons (LEXV . DYNV), the car and cdr being lists of the +lexically and dynamically bound symbols actually used by FORM." (let* ((fun ;; Wrap FORM into a function because the analysis code we ;; have only computes freevars for functions. @@ -875,11 +882,19 @@ Returns a pair (LEXV . DYNV) of those vars actually used by FORM." (cons fvs dyns))))) (defun cconv-make-interpreted-closure (fun env) + "Make a closure for the interpreter. +This function is evaluated both at compile time and run time. +FUN, the closure's function, must be a lambda form. +ENV, the closure's environment, is a mixture of lexical bindings of the form +(SYMBOL . VALUE) and symbols which indicate dynamic bindings of those +symbols." (cl-assert (eq (car-safe fun) 'lambda)) (let ((lexvars (delq nil (mapcar #'car-safe env)))) - (if (null lexvars) - ;; The lexical environment is empty, so there's no need to - ;; look for free variables. + (if (or cconv-dont-trim-unused-variables (null lexvars)) + ;; The lexical environment is empty, or needs to be preserved, + ;; so there's no need to look for free variables. + ;; Attempting to replace ,(cdr fun) by a macroexpanded version + ;; causes bootstrap to fail. `(closure ,env . ,(cdr fun)) ;; We could try and cache the result of the macroexpansion and ;; `cconv-fv' analysis. Not sure it's worth the trouble. @@ -896,7 +911,7 @@ Returns a pair (LEXV . DYNV) of those vars actually used by FORM." (pcase expanded-form (`#'(lambda . ,cdr) cdr) (_ (cdr fun)))) - + (dynvars (delq nil (mapcar (lambda (b) (if (symbolp b) b)) env))) (fvs (cconv-fv expanded-form lexvars dynvars)) (newenv (nconc (mapcar (lambda (fv) (assq fv env)) (car fvs)) |