3 ;;; Code generation protocol implementation
5 ;;; (c) 2009 Straylight/Edgeware
8 ;;;----- Licensing notice ---------------------------------------------------
10 ;;; This file is part of the Sensible Object Design, an object system for C.
12 ;;; SOD is free software; you can redistribute it and/or modify
13 ;;; it under the terms of the GNU General Public License as published by
14 ;;; the Free Software Foundation; either version 2 of the License, or
15 ;;; (at your option) any later version.
17 ;;; SOD is distributed in the hope that it will be useful,
18 ;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
19 ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 ;;; GNU General Public License for more details.
22 ;;; You should have received a copy of the GNU General Public License
23 ;;; along with SOD; if not, write to the Free Software Foundation,
24 ;;; Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
28 ;;;--------------------------------------------------------------------------
31 (export '(temporary-argument temporary-function))
32 (defclass temporary-argument (temporary-name) ())
33 (defclass temporary-function (temporary-name) ())
35 (export 'temporary-variable)
36 (defclass temporary-variable (temporary-name)
37 ((in-use-p :initarg :in-use-p :initform nil
38 :type boolean :accessor var-in-use-p)))
40 (define-module-var *temporary-index* 0
41 "Index for temporary name generation.
43 This is automatically reset to zero before the output functions are
44 invoked to write a file. This way, we can ensure that the same output
45 file is always produced from the same input.")
47 (define-clear-the-decks reset-codegen-index
48 (setf *temporary-index* 0))
50 (defmethod commentify-argument-name ((name temporary-name))
53 (defun temporary-function ()
54 "Return a temporary function name."
55 (make-instance 'temporary-function
56 :tag (prog1 *temporary-index* (incf *temporary-index*))))
58 (defmethod format-temporary-name ((var temporary-name) stream)
59 (format stream "~A" (temp-tag var)))
60 (defmethod format-temporary-name ((var temporary-argument) stream)
61 (format stream "sod__a~A" (temp-tag var)))
62 (defmethod format-temporary-name ((var temporary-variable) stream)
63 (format stream "sod__v~A" (temp-tag var)))
64 (defmethod format-temporary-name ((var temporary-function) stream)
65 (format stream "sod__f~A" (temp-tag var)))
67 (defmethod print-object ((var temporary-name) stream)
69 (print-unreadable-object (var stream :type t)
70 (prin1 (temp-tag var) stream))
71 (format-temporary-name var stream)))
73 ;;;--------------------------------------------------------------------------
74 ;;; Code generator objects.
76 (defclass basic-codegen ()
77 ((vars :initarg :vars :initform nil :type list :accessor codegen-vars)
78 (insts :initarg :insts :initform nil :type list :accessor codegen-insts)
79 (temp-index :initarg :temp-index :initform 0
80 :type fixnum :accessor codegen-temp-index))
82 "Base class for code generator state.
84 This contains the bare essentials for supporting the `emit-inst' and
85 `ensure-var' protocols; see the documentation for those generic functions
88 This class isn't abstract. A full `codegen' object uses instances of this
89 to keep track of pending functions which haven't been completed yet.
91 Just in case that wasn't clear enough: this is nothing to do with the
94 (defmethod emit-inst ((codegen basic-codegen) inst)
95 (push inst (codegen-insts codegen)))
97 (defmethod emit-insts ((codegen basic-codegen) insts)
98 (asetf (codegen-insts codegen) (revappend insts it)))
100 (defmethod emit-decl ((codegen basic-codegen) inst)
101 (push inst (codegen-vars codegen)))
103 (defmethod emit-decls ((codegen basic-codegen) insts)
104 (asetf (codegen-vars codegen) (revappend insts it)))
106 (defmethod ensure-var ((codegen basic-codegen) name type &optional init)
107 (let* ((vars (codegen-vars codegen))
109 (remove-if-not (lambda (var) (typep var 'var-inst)) vars)
110 :key #'inst-name :test #'equal)))
112 (setf (codegen-vars codegen)
113 (cons (make-var-inst name type init) vars)))
114 ((not (c-type-equal-p type (inst-type var)))
115 (error "(Internal) Redefining type for variable ~A" name)))
119 (defclass codegen (basic-codegen)
120 ((functions :initform nil :type list :reader codegen-functions)
121 (stack :initform nil :type list :accessor codegen-stack))
123 "A full-fat code generator which can generate and track functions.
125 This is the real deal. Subclasses may which to attach additional state
126 for convenience's sake, but this class is self-contained. It supports the
127 `codegen-push', `codegen-pop' and `codegen-pop-function' protocols."))
129 (defmethod codegen-push ((codegen codegen))
130 (with-slots (vars insts temp-index stack) codegen
131 (push (make-instance 'basic-codegen
134 :temp-index temp-index)
136 (setf vars nil insts nil temp-index 0)))
138 (defmethod codegen-pop ((codegen codegen))
139 (with-slots (vars insts temp-index stack) codegen
140 (multiple-value-prog1
141 (values (nreverse vars) (nreverse insts))
142 (let ((sub (pop stack)))
143 (setf vars (codegen-vars sub)
144 insts (codegen-insts sub)
145 temp-index (codegen-temp-index sub))))))
147 (defmethod codegen-add-function ((codegen codegen) function)
148 (with-slots (functions) codegen
149 (setf functions (nconc functions (list function)))))
151 (defmethod temporary-var ((codegen basic-codegen) type)
152 (with-slots (vars temp-index) codegen
153 (or (some (lambda (var)
154 (let ((name (inst-name var)))
155 (if (and (not (var-in-use-p name))
156 (c-type-equal-p type (inst-type var)))
159 (remove-if-not (lambda (var) (typep var 'var-inst)) vars))
160 (let* ((name (make-instance 'temporary-variable
162 :tag (prog1 temp-index
163 (incf temp-index)))))
164 (push (make-var-inst name type) vars)
167 ;;;----- That's all, folks --------------------------------------------------