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1f1d88f5 MW |
1 | ;;; -*-lisp-*- |
2 | ;;; | |
dea4d055 | 3 | ;;; Code generation protocol |
1f1d88f5 MW |
4 | ;;; |
5 | ;;; (c) 2009 Straylight/Edgeware | |
6 | ;;; | |
7 | ||
8 | ;;;----- Licensing notice --------------------------------------------------- | |
9 | ;;; | |
e0808c47 | 10 | ;;; This file is part of the Sensible Object Design, an object system for C. |
1f1d88f5 MW |
11 | ;;; |
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. | |
16 | ;;; | |
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. | |
21 | ;;; | |
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. | |
25 | ||
26 | (cl:in-package #:sod) | |
27 | ||
28 | ;;;-------------------------------------------------------------------------- | |
29 | ;;; Temporary names. | |
30 | ||
dea4d055 MW |
31 | ;; Protocol. |
32 | ||
33 | (export 'format-temporary-name) | |
34 | (defgeneric format-temporary-name (var stream) | |
1f1d88f5 | 35 | (:documentation |
dea4d055 | 36 | "Write the name of a temporary variable VAR to STREAM.")) |
1f1d88f5 | 37 | |
dea4d055 MW |
38 | (export 'var-in-use-p) |
39 | (defgeneric var-in-use-p (var) | |
40 | (:documentation | |
3109662a | 41 | "Answer whether VAR is currently being used. See `with-temporary-var'.") |
dea4d055 MW |
42 | (:method (var) |
43 | "Non-temporary variables are always in use." | |
1d8cc67a | 44 | (declare (ignore var)) |
dea4d055 MW |
45 | t)) |
46 | (defgeneric (setf var-in-use-p) (value var) | |
47 | (:documentation | |
3109662a | 48 | "Record whether VAR is currently being used. See `with-temporary-var'.")) |
1f1d88f5 | 49 | |
dea4d055 | 50 | ;; Root class. |
1f1d88f5 | 51 | |
1344e1f9 | 52 | (export '(temporary-name temp-tag)) |
dea4d055 MW |
53 | (defclass temporary-name () |
54 | ((tag :initarg :tag :reader temp-tag)) | |
55 | (:documentation | |
56 | "Base class for temporary variable and argument names.")) | |
1f1d88f5 | 57 | |
dea4d055 | 58 | ;; Important temporary names. |
1f1d88f5 | 59 | |
dea4d055 | 60 | (export '(*sod-ap* *sod-master-ap*)) |
1f1d88f5 MW |
61 | (defparameter *sod-ap* |
62 | (make-instance 'temporary-name :tag "sod__ap")) | |
63 | (defparameter *sod-master-ap* | |
64 | (make-instance 'temporary-name :tag "sod__master_ap")) | |
2bbe0f1d MW |
65 | (defparameter *sod-tmp-ap* |
66 | (make-instance 'temporary-name :tag "sod__tmp_ap")) | |
1d8206e9 MW |
67 | (defparameter *sod-tmp-val* |
68 | (make-instance 'temporary-name :tag "sod__t")) | |
43073476 MW |
69 | (defparameter *sod-keywords* |
70 | (make-instance 'temporary-name :tag "sod__kw")) | |
71 | (defparameter *sod-key-pointer* | |
72 | (make-instance 'temporary-name :tag "sod__keys")) | |
1f1d88f5 | 73 | |
944caf84 MW |
74 | (export '*null-pointer*) |
75 | (defparameter *null-pointer* "NULL") | |
76 | ||
1f1d88f5 MW |
77 | ;;;-------------------------------------------------------------------------- |
78 | ;;; Instructions. | |
79 | ||
dea4d055 MW |
80 | ;; Classes. |
81 | ||
82 | (export 'inst) | |
1f1d88f5 MW |
83 | (defclass inst () () |
84 | (:documentation | |
85 | "A base class for instructions. | |
86 | ||
87 | An `instruction' is anything which might be useful to string into a code | |
9ec578d9 MW |
88 | generator. Both statements and expressions can be represented by trees of |
89 | instructions. The `definst' macro is a convenient way of defining new | |
90 | instructions. | |
1f1d88f5 MW |
91 | |
92 | The only important protocol for instructions is output, which is achieved | |
3109662a | 93 | by calling `print-object' with `*print-escape*' nil. |
1f1d88f5 MW |
94 | |
95 | This doesn't really do very much, but it acts as a handy marker for | |
96 | instruction subclasses.")) | |
97 | ||
dea4d055 | 98 | (export 'inst-metric) |
1f1d88f5 MW |
99 | (defgeneric inst-metric (inst) |
100 | (:documentation | |
101 | "Returns a `metric' describing how complicated INST is. | |
102 | ||
3109662a MW |
103 | The default metric of an inst node is simply 1; `inst' subclasses |
104 | generated by `definst' (q.v.) have an automatically generated method which | |
105 | returns one plus the sum of the metrics of the node's children. | |
1f1d88f5 MW |
106 | |
107 | This isn't intended to be a particularly rigorous definition. Its purpose | |
108 | is to allow code generators to make decisions about inlining or calling | |
109 | code fairly simply.") | |
9ec578d9 MW |
110 | (:method ((inst t)) |
111 | (declare (ignore inst)) | |
112 | 1) | |
113 | (:method ((inst null)) | |
1d8cc67a | 114 | (declare (ignore inst)) |
9ec578d9 MW |
115 | 1) |
116 | (:method ((inst list)) | |
117 | (reduce #'+ inst :key #'inst-metric))) | |
1f1d88f5 | 118 | |
dea4d055 MW |
119 | ;; Instruction definition. |
120 | ||
121 | (export 'definst) | |
418752c5 | 122 | (defmacro definst (code (streamvar &key export) args &body body) |
1f1d88f5 MW |
123 | "Define an instruction type and describe how to output it. |
124 | ||
3109662a MW |
125 | An `inst' can represent any structured piece of output syntax: a |
126 | statement, expression or declaration, for example. This macro defines the | |
127 | following things: | |
1f1d88f5 | 128 | |
3109662a | 129 | * A class `CODE-inst' to represent the instruction. |
1f1d88f5 MW |
130 | |
131 | * Instance slots named after the ARGS, with matching keyword initargs, | |
3109662a | 132 | and `inst-ARG' readers. |
1f1d88f5 | 133 | |
167524b5 MW |
134 | * A constructor `make-CODE-inst' which accepts the ARGS (as an ordinary |
135 | BVL) as arguments and returns a fresh instance. | |
1f1d88f5 | 136 | |
3109662a | 137 | * A print method, which prints a diagnostic dump if `*print-escape*' is |
1f1d88f5 MW |
138 | set, or invokes the BODY (with STREAMVAR bound to the output stream) |
139 | otherwise. The BODY is expected to produce target code at this | |
418752c5 MW |
140 | point. |
141 | ||
142 | If EXPORT is non-nil, then export the `CODE-inst' and `make-CODE-inst' | |
143 | symbols." | |
1f1d88f5 | 144 | |
167524b5 MW |
145 | (let* ((inst-var (gensym "INST")) |
146 | (class-name (symbolicate code '-inst)) | |
147 | (constructor-name (symbolicate 'make- code '-inst)) | |
148 | (slots (mapcan (lambda (arg) | |
149 | (if (listp arg) (list (car arg)) | |
150 | (let ((name (symbol-name arg))) | |
151 | (if (and (plusp (length name)) | |
152 | (char/= (char name 0) #\&)) | |
153 | (list arg) | |
154 | nil)))) | |
155 | args)) | |
156 | (keys (mapcar (lambda (arg) (intern (symbol-name arg) :keyword)) | |
157 | slots))) | |
1f1d88f5 MW |
158 | `(progn |
159 | (defclass ,class-name (inst) | |
167524b5 MW |
160 | ,(mapcar (lambda (slot key) |
161 | `(,slot :initarg ,key | |
162 | :reader ,(symbolicate 'inst- slot))) | |
163 | slots keys)) | |
418752c5 | 164 | (defun ,constructor-name (,@args) |
167524b5 | 165 | (make-instance ',class-name ,@(mappend #'list keys slots))) |
1f1d88f5 | 166 | (defmethod inst-metric ((,inst-var ,class-name)) |
167524b5 MW |
167 | (with-slots (,@slots) ,inst-var |
168 | (+ 1 ,@(mapcar (lambda (slot) `(inst-metric ,slot)) slots)))) | |
1f1d88f5 | 169 | (defmethod print-object ((,inst-var ,class-name) ,streamvar) |
167524b5 | 170 | (with-slots (,@slots) ,inst-var |
1f1d88f5 MW |
171 | (if *print-escape* |
172 | (print-unreadable-object (,inst-var ,streamvar :type t) | |
173 | (format stream "~@<~@{~S ~@_~S~^ ~_~}~:>" | |
167524b5 | 174 | ,@(mappend #'list keys slots))) |
fc09e191 | 175 | (block ,code ,@body)))) |
34c51b1c | 176 | ,@(and export `((export '(,class-name ,constructor-name |
167524b5 MW |
177 | ,@(mapcar (lambda (slot) |
178 | (symbolicate 'inst- slot)) | |
179 | slots))))) | |
418752c5 | 180 | ',code))) |
1f1d88f5 | 181 | |
dea4d055 MW |
182 | ;; Formatting utilities. |
183 | ||
1f1d88f5 | 184 | (defun format-compound-statement* (stream child morep thunk) |
3109662a | 185 | "Underlying function for `format-compound-statement'." |
1f1d88f5 MW |
186 | (cond ((typep child 'block-inst) |
187 | (funcall thunk stream) | |
188 | (write-char #\space stream) | |
189 | (princ child stream) | |
190 | (when morep (write-char #\space stream))) | |
191 | (t | |
192 | (pprint-logical-block (stream nil) | |
193 | (funcall thunk stream) | |
194 | (write-char #\space stream) | |
195 | (pprint-indent :block 2 stream) | |
196 | (pprint-newline :linear stream) | |
197 | (princ child stream) | |
243cffbf MW |
198 | (pprint-indent :block 0 stream)) |
199 | (case morep | |
200 | (:space | |
201 | (write-char #\space stream) | |
202 | (pprint-newline :linear stream)) | |
203 | ((t) | |
204 | (pprint-newline :mandatory stream)))))) | |
1f1d88f5 | 205 | |
dea4d055 | 206 | (export 'format-compound-statement) |
1f1d88f5 MW |
207 | (defmacro format-compound-statement |
208 | ((stream child &optional morep) &body body) | |
209 | "Format a compound statement to STREAM. | |
210 | ||
211 | The introductory material is printed by BODY. The CHILD is formatted | |
3109662a | 212 | properly according to whether it's a `block-inst'. If MOREP is true, then |
1f1d88f5 MW |
213 | allow for more stuff following the child." |
214 | `(format-compound-statement* ,stream ,child ,morep | |
215 | (lambda (,stream) ,@body))) | |
216 | ||
7de8c666 MW |
217 | (export 'format-banner-comment) |
218 | (defun format-banner-comment (stream control &rest args) | |
219 | (format stream "~@</~@<* ~@;~?~:>~_ */~:>" control args)) | |
220 | ||
77d83e01 MW |
221 | ;; Important instruction classes. |
222 | ||
223 | ;; HACK: Some of the slot names we'd like to use are external symbols in our | |
224 | ;; package or the `common-lisp' package. Use gensyms for these slot names to | |
225 | ;; prevent them from leaking. | |
226 | ||
167524b5 | 227 | (definst var (stream :export t) (name #1=#:type &optional init) |
243cffbf MW |
228 | (pprint-logical-block (stream nil) |
229 | (pprint-c-type #1# stream name) | |
230 | (when init | |
231 | (format stream " = ~2I~_~A" init)) | |
232 | (write-char #\; stream))) | |
77d83e01 | 233 | |
7de8c666 MW |
234 | (definst function (stream :export t) |
235 | (name #1=#:type body &optional #2=#:banner &rest banner-args) | |
77d83e01 | 236 | (pprint-logical-block (stream nil) |
7de8c666 MW |
237 | (when #2# |
238 | (apply #'format-banner-comment stream #2# banner-args) | |
239 | (pprint-newline :mandatory stream)) | |
77d83e01 MW |
240 | (princ "static " stream) |
241 | (pprint-c-type #1# stream name) | |
242 | (format stream "~:@_~A~:@_~:@_" body))) | |
243 | ||
244 | ;; Expression statements. | |
245 | (definst expr (stream :export t) (#1=#:expr) | |
246 | (format stream "~A;" #1#)) | |
247 | (definst set (stream :export t) (var #1=#:expr) | |
243cffbf | 248 | (format stream "~@<~A = ~2I~_~A;~:>" var #1#)) |
77d83e01 | 249 | (definst update (stream :export t) (var op #1=#:expr) |
243cffbf | 250 | (format stream "~@<~A ~A= ~2I~_~A;~:>" var op #1#)) |
77d83e01 MW |
251 | |
252 | ;; Special kinds of expressions. | |
167524b5 | 253 | (definst call (stream :export t) (#1=#:func &rest args) |
243cffbf | 254 | (format stream "~@<~A~4I~_(~@<~{~A~^, ~_~}~:>)~:>" #1# args)) |
2d8d81c5 MW |
255 | (definst cond (stream :export t) (#1=#:cond conseq alt) |
256 | (format stream "~@<~A ~2I~@_~@<? ~A ~_: ~A~:>~:>" #1# conseq alt)) | |
77d83e01 MW |
257 | |
258 | ;; Simple statements. | |
259 | (definst return (stream :export t) (#1=#:expr) | |
260 | (format stream "return~@[ (~A)~];" #1#)) | |
261 | (definst break (stream :export t) () | |
262 | (format stream "break;")) | |
263 | (definst continue (stream :export t) () | |
264 | (format stream "continue;")) | |
265 | ||
266 | ;; Compound statements. | |
267 | ||
7de8c666 MW |
268 | (defvar *first-statement-p* t |
269 | "True if this is the first statement in a block. | |
270 | ||
271 | This is used to communicate between `block-inst' and `banner-inst' so that | |
272 | they get the formatting right between them.") | |
273 | ||
274 | (definst banner (stream :export t) (control &rest args) | |
275 | (pprint-logical-block (stream nil) | |
276 | (unless *first-statement-p* (pprint-newline :mandatory stream)) | |
277 | (apply #'format-banner-comment stream control args))) | |
278 | ||
279 | (export 'emit-banner) | |
280 | (defun emit-banner (codegen control &rest args) | |
281 | (emit-inst codegen (apply #'make-banner-inst control args))) | |
282 | ||
77d83e01 | 283 | (definst block (stream :export t) (decls body) |
e5573634 MW |
284 | (write-char #\{ stream) |
285 | (pprint-newline :mandatory stream) | |
286 | (pprint-logical-block (stream nil) | |
287 | (let ((newlinep nil)) | |
288 | (flet ((newline () | |
289 | (if newlinep | |
290 | (pprint-newline :mandatory stream) | |
291 | (setf newlinep t)))) | |
292 | (pprint-indent :block 2 stream) | |
293 | (write-string " " stream) | |
294 | (when decls | |
295 | (dolist (decl decls) | |
296 | (newline) | |
297 | (write decl :stream stream)) | |
298 | (when body (newline))) | |
7de8c666 MW |
299 | (let ((*first-statement-p* t)) |
300 | (dolist (inst body) | |
301 | (newline) | |
302 | (write inst :stream stream) | |
303 | (setf *first-statement-p* nil)))))) | |
e5573634 MW |
304 | (pprint-newline :mandatory stream) |
305 | (write-char #\} stream)) | |
77d83e01 | 306 | |
167524b5 | 307 | (definst if (stream :export t) (#1=#:cond conseq &optional alt) |
d6bb2ccd MW |
308 | (let ((stmt "if")) |
309 | (loop (format-compound-statement (stream conseq (if alt t nil)) | |
310 | (format stream "~A (~A)" stmt #1#)) | |
311 | (typecase alt | |
312 | (null (return)) | |
313 | (if-inst (setf stmt "else if" | |
314 | #1# (inst-cond alt) | |
315 | conseq (inst-conseq alt) | |
316 | alt (inst-alt alt))) | |
317 | (t (format-compound-statement (stream alt) | |
318 | (format stream "else")) | |
319 | (return)))))) | |
77d83e01 MW |
320 | |
321 | (definst while (stream :export t) (#1=#:cond body) | |
322 | (format-compound-statement (stream body) | |
323 | (format stream "while (~A)" #1#))) | |
324 | ||
325 | (definst do-while (stream :export t) (body #1=#:cond) | |
326 | (format-compound-statement (stream body :space) | |
327 | (write-string "do" stream)) | |
328 | (format stream "while (~A);" #1#)) | |
329 | ||
2d8d81c5 MW |
330 | (definst for (stream :export t) (init #1=#:cond update body) |
331 | (format-compound-statement (stream body) | |
332 | (format stream "for (~@<~@[~A~];~@[ ~_~A~];~@[ ~_~A~]~:>)" | |
333 | init #1# update))) | |
334 | ||
1f1d88f5 | 335 | ;;;-------------------------------------------------------------------------- |
dea4d055 | 336 | ;;; Code generation. |
1f1d88f5 | 337 | |
dea4d055 | 338 | ;; Accessors. |
1f1d88f5 | 339 | |
dea4d055 MW |
340 | (export 'codegen-functions) |
341 | (defgeneric codegen-functions (codegen) | |
1f1d88f5 | 342 | (:documentation |
3109662a | 343 | "Return the list of `function-inst's of completed functions.")) |
1f1d88f5 | 344 | |
dea4d055 | 345 | (export 'ensure-var) |
1f1d88f5 MW |
346 | (defgeneric ensure-var (codegen name type &optional init) |
347 | (:documentation | |
348 | "Add a variable to CODEGEN's list. | |
349 | ||
3109662a | 350 | The variable is called NAME (which should be comparable using `equal' and |
1f1d88f5 | 351 | print to an identifier) and has the given TYPE. If INIT is present and |
3109662a | 352 | non-nil it is an expression `inst' used to provide the variable with an |
dea4d055 | 353 | initial value.")) |
1f1d88f5 | 354 | |
dea4d055 MW |
355 | (export '(emit-inst emit-insts)) |
356 | (defgeneric emit-inst (codegen inst) | |
357 | (:documentation | |
358 | "Add INST to the end of CODEGEN's list of instructions.")) | |
359 | (defgeneric emit-insts (codegen insts) | |
360 | (:documentation | |
361 | "Add a list of INSTS to the end of CODEGEN's list of instructions.") | |
362 | (:method (codegen insts) | |
363 | (dolist (inst insts) (emit-inst codegen inst)))) | |
1f1d88f5 | 364 | |
3f4ac959 MW |
365 | (export '(emit-decl emit-decls)) |
366 | (defgeneric emit-decl (codegen inst) | |
367 | (:documentation | |
368 | "Add INST to the end of CODEGEN's list of declarations.")) | |
369 | (defgeneric emit-decls (codegen insts) | |
370 | (:documentation | |
371 | "Add a list of INSTS to the end of CODEGEN's list of declarations.")) | |
372 | ||
dea4d055 | 373 | (export 'codegen-push) |
1f1d88f5 MW |
374 | (defgeneric codegen-push (codegen) |
375 | (:documentation | |
376 | "Pushes the current code generation state onto a stack. | |
377 | ||
dea4d055 | 378 | The state consists of the accumulated variables and instructions.")) |
1f1d88f5 | 379 | |
dea4d055 | 380 | (export 'codegen-pop) |
1f1d88f5 MW |
381 | (defgeneric codegen-pop (codegen) |
382 | (:documentation | |
383 | "Pops a saved state off of the CODEGEN's stack. | |
384 | ||
385 | Returns the newly accumulated variables and instructions as lists, as | |
dea4d055 | 386 | separate values.")) |
1f1d88f5 | 387 | |
dea4d055 | 388 | (export 'codegen-add-function) |
1f1d88f5 MW |
389 | (defgeneric codegen-add-function (codegen function) |
390 | (:documentation | |
391 | "Adds a function to CODEGEN's list. | |
392 | ||
393 | Actually, we're not picky: FUNCTION can be any kind of object that you're | |
3109662a | 394 | willing to find in the list returned by `codegen-functions'.")) |
dea4d055 MW |
395 | |
396 | (export 'temporary-var) | |
397 | (defgeneric temporary-var (codegen type) | |
398 | (:documentation | |
399 | "Return the name of a temporary variable. | |
400 | ||
401 | The temporary variable will have the given TYPE, and will be marked | |
402 | in-use. You should clear the in-use flag explicitly when you've finished | |
3109662a MW |
403 | with the variable -- or, better, use `with-temporary-var' to do the |
404 | cleanup automatically.")) | |
1f1d88f5 | 405 | |
dea4d055 | 406 | (export 'codegen-build-function) |
7de8c666 MW |
407 | (defun codegen-build-function |
408 | (codegen name type vars insts &optional banner &rest banner-args) | |
1f1d88f5 MW |
409 | "Build a function and add it to CODEGEN's list. |
410 | ||
411 | Returns the function's name." | |
412 | (codegen-add-function codegen | |
7de8c666 MW |
413 | (apply #'make-function-inst name type |
414 | (make-block-inst vars insts) | |
415 | banner banner-args)) | |
1f1d88f5 MW |
416 | name) |
417 | ||
dea4d055 MW |
418 | (export 'codegen-pop-block) |
419 | (defgeneric codegen-pop-block (codegen) | |
420 | (:documentation | |
3109662a | 421 | "Makes a block (`block-inst') out of the completed code in CODEGEN.") |
dea4d055 MW |
422 | (:method (codegen) |
423 | (multiple-value-bind (vars insts) (codegen-pop codegen) | |
424 | (make-block-inst vars insts)))) | |
425 | ||
426 | (export 'codegen-pop-function) | |
7de8c666 MW |
427 | (defgeneric codegen-pop-function |
428 | (codegen name type &optional banner &rest banner-args) | |
1f1d88f5 MW |
429 | (:documentation |
430 | "Makes a function out of the completed code in CODEGEN. | |
431 | ||
432 | The NAME can be any object you like. The TYPE should be a function type | |
433 | object which includes argument names. The return value is the NAME.") | |
7de8c666 | 434 | (:method (codegen name type &optional banner &rest banner-args) |
1f1d88f5 | 435 | (multiple-value-bind (vars insts) (codegen-pop codegen) |
7de8c666 MW |
436 | (apply #'codegen-build-function codegen name type vars insts |
437 | banner banner-args)))) | |
1f1d88f5 | 438 | |
dea4d055 | 439 | (export 'with-temporary-var) |
1f1d88f5 MW |
440 | (defmacro with-temporary-var ((codegen var type) &body body) |
441 | "Evaluate BODY with VAR bound to a temporary variable name. | |
442 | ||
443 | During BODY, VAR will be marked in-use; when BODY ends, VAR will be marked | |
9ec578d9 | 444 | available for re-use." |
b8c698ee MW |
445 | (multiple-value-bind (doc decls body) (parse-body body :docp nil) |
446 | (declare (ignore doc)) | |
447 | `(let ((,var (temporary-var ,codegen ,type))) | |
448 | ,@decls | |
449 | (unwind-protect | |
450 | (progn ,@body) | |
451 | (setf (var-in-use-p ,var) nil))))) | |
1f1d88f5 MW |
452 | |
453 | ;;;-------------------------------------------------------------------------- | |
454 | ;;; Code generation idioms. | |
455 | ||
dea4d055 | 456 | (export 'deliver-expr) |
1f1d88f5 MW |
457 | (defun deliver-expr (codegen target expr) |
458 | "Emit code to deliver the value of EXPR to the TARGET. | |
459 | ||
460 | The TARGET may be one of the following. | |
461 | ||
3109662a | 462 | * `:void', indicating that the value is to be discarded. The expression |
1f1d88f5 MW |
463 | will still be evaluated. |
464 | ||
3109662a MW |
465 | * `:void-return', indicating that the value is to be discarded (as for |
466 | `:void') and furthermore a `return' from the current function should | |
467 | be forced after computing the value. | |
1f1d88f5 | 468 | |
3109662a MW |
469 | * `:return', indicating that the value is to be returned from the |
470 | current function. | |
1f1d88f5 MW |
471 | |
472 | * A variable name, indicating that the value is to be stored in the | |
473 | variable. | |
474 | ||
3109662a MW |
475 | In the cases of `:return', `:void' and `:void-return' targets, it is valid |
476 | for EXPR to be nil; this signifies that no computation needs to be | |
477 | performed. Variable-name targets require an expression." | |
1f1d88f5 MW |
478 | |
479 | (case target | |
480 | (:return (emit-inst codegen (make-return-inst expr))) | |
481 | (:void (when expr (emit-inst codegen (make-expr-inst expr)))) | |
482 | (:void-return (when expr (emit-inst codegen (make-expr-inst expr))) | |
483 | (emit-inst codegen (make-return-inst nil))) | |
484 | (t (emit-inst codegen (make-set-inst target expr))))) | |
485 | ||
dea4d055 | 486 | (export 'convert-stmts) |
1f1d88f5 | 487 | (defun convert-stmts (codegen target type func) |
3109662a | 488 | "Invoke FUNC to deliver a value to a non-`:return' target. |
1f1d88f5 | 489 | |
3109662a MW |
490 | FUNC is a function which accepts a single argument, a non-`:return' |
491 | target, and generates statements which deliver a value (see | |
492 | `deliver-expr') of the specified TYPE to this target. In general, the | |
493 | generated code will have the form | |
1f1d88f5 MW |
494 | |
495 | setup instructions... | |
3109662a | 496 | (deliver-expr CODEGEN TARGET (compute value...)) |
1f1d88f5 MW |
497 | cleanup instructions... |
498 | ||
499 | where the cleanup instructions are essential to the proper working of the | |
500 | generated program. | |
501 | ||
3109662a MW |
502 | The `convert-stmts' function will call FUNC to generate code, and arrange |
503 | that its value is correctly delivered to TARGET, regardless of what the | |
504 | TARGET is -- i.e., it lifts the restriction to non-`:return' targets. It | |
505 | does this by inventing a new temporary variable." | |
1f1d88f5 MW |
506 | |
507 | (case target | |
508 | (:return (with-temporary-var (codegen var type) | |
509 | (funcall func var) | |
510 | (deliver-expr codegen target var))) | |
511 | (:void-return (funcall func :void) | |
512 | (emit-inst codegen (make-return-inst nil))) | |
513 | (t (funcall func target)))) | |
514 | ||
357885be MW |
515 | (export 'deliver-call) |
516 | (defun deliver-call (codegen target func &rest args) | |
517 | "Emit a statement to call FUNC with ARGS and deliver the result to TARGET." | |
167524b5 | 518 | (deliver-expr codegen target (apply #'make-call-inst func args))) |
357885be | 519 | |
1f1d88f5 | 520 | ;;;----- That's all, folks -------------------------------------------------- |