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