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1 | ;;; -*-lisp-*- |
2 | ;;; | |
3 | ;;; Infrastructure for effective method generation | |
4 | ;;; | |
5 | ;;; (c) 2009 Straylight/Edgeware | |
6 | ;;; | |
7 | ||
8 | ;;;----- Licensing notice --------------------------------------------------- | |
9 | ;;; | |
10 | ;;; This file is part of the Simple Object Definition system. | |
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 | ;;; Function type protocol. | |
30 | ||
31 | (defgeneric sod-message-argument-tail (message) | |
32 | (:documentation | |
33 | "Return the argument tail for the message, with invented argument names. | |
34 | ||
35 | No `me' argument is prepended; any :ELLIPSIS is left as it is.")) | |
36 | ||
37 | (defgeneric sod-message-no-varargs-tail (message) | |
38 | (:documentation | |
39 | "Return the argument tail for the message with :ELLIPSIS substituted. | |
40 | ||
41 | As with SOD-MESSAGE-ARGUMENT-TAIL, no `me' argument is prepended. | |
42 | However, an :ELLIPSIS is replaced by an argument of type `va_list', named | |
43 | `sod__ap'.")) | |
44 | ||
45 | (defgeneric direct-method-function-type (method) | |
46 | (:documentation | |
47 | "Return the C function type for the direct method. | |
48 | ||
49 | This is called during initialization of a direct method object, and the | |
50 | result is cached. | |
51 | ||
52 | A default method is provided (by BASIC-DIRECT-METHOD) which simply | |
53 | prepends an appropriate `me' argument to the user-provided argument list. | |
54 | Fancy method classes may need to override this behaviour.")) | |
55 | ||
56 | (defgeneric direct-method-next-method-type (method) | |
57 | (:documentation | |
58 | "Return the C function type for the next-method trampoline. | |
59 | ||
60 | This is called during initialization of a direct method object, and the | |
61 | result is cached. It should return a function type, not a pointer type. | |
62 | ||
63 | A default method is provided (by DELEGATING-DIRECT-METHOD) which should do | |
64 | the right job. Very fancy subclasses might need to do something | |
65 | different.")) | |
66 | ||
67 | (defgeneric direct-method-function-name (method) | |
68 | (:documentation | |
69 | "Return the C function name for the direct method.")) | |
70 | ||
71 | ;;;-------------------------------------------------------------------------- | |
72 | ;;; Message classes. | |
73 | ||
74 | (defclass basic-message (sod-message) | |
75 | ((argument-tail :type list :reader sod-message-argument-tail) | |
76 | (no-varargs-tail :type list :reader sod-message-no-varargs-tail)) | |
77 | (:documentation | |
78 | "Base class for built-in message classes. | |
79 | ||
80 | Provides the basic functionality for the built-in method combinations. | |
81 | This is a separate class so that `special effect' messages can avoid | |
82 | inheriting its default behaviour. | |
83 | ||
84 | The function type protocol is implemented on BASIC-MESSAGE using slot | |
85 | reader methods. The actual values are computed on demand in methods | |
86 | defined on SLOT-UNBOUND.")) | |
87 | ||
88 | ;;; Function type protocol. | |
89 | ||
90 | (defmethod slot-unbound (class | |
91 | (message basic-message) | |
92 | (slot-name (eql 'argument-tail))) | |
93 | (let ((seq 0)) | |
94 | (mapcar (lambda (arg) | |
95 | (if (or (eq arg :ellipsis) (argument-name arg)) | |
96 | arg | |
97 | (make-argument (make-instance 'temporary-argument | |
98 | :tag (prog1 seq (incf seq))) | |
99 | (argument-type arg)))) | |
100 | (c-function-arguments (sod-message-type message))))) | |
101 | ||
102 | (defmethod slot-unbound (class | |
103 | (message basic-message) | |
104 | (slot-name (eql 'no-varargs-tail))) | |
105 | (mapcar (lambda (arg) | |
106 | (if (eq arg :ellipsis) | |
107 | (make-argument *sod-ap* (c-type va-list)) | |
108 | arg)) | |
109 | (sod-message-argument-tail message))) | |
110 | ||
111 | ;;; Method class selection. | |
112 | ||
113 | (defmethod sod-message-method-class | |
114 | ((message basic-message) (class sod-class) pset) | |
115 | (let ((role (get-property pset :role :keyword nil))) | |
116 | (case role | |
117 | ((:before :after) 'daemon-direct-method) | |
118 | (:around 'delegating-direct-method) | |
119 | ((nil) (error "How odd: a primary method slipped through the net")) | |
120 | (t (error "Unknown method role ~A" role))))) | |
121 | ||
122 | ;;; Utility functions. | |
123 | ||
124 | (defun varargs-message-p (message) | |
125 | "Answer whether the MESSAGE accepts a variable-length argument list. | |
126 | ||
127 | We need to jump through some extra hoops in order to cope with varargs | |
128 | messages, so this is useful to know." | |
129 | (member :ellipsis (sod-message-argument-tail message))) | |
130 | ||
131 | ;;;-------------------------------------------------------------------------- | |
132 | ;;; Direct method classes. | |
133 | ||
134 | (defclass basic-direct-method (sod-method) | |
135 | ((role :initarg :role | |
136 | :type symbol | |
137 | :reader sod-method-role) | |
138 | (function-type :type c-function-type | |
139 | :reader sod-method-function-type)) | |
140 | (:documentation | |
141 | "Base class for built-in direct method classes. | |
142 | ||
143 | Provides the basic functionality for the built-in direct-method classes. | |
144 | This is a separate class so that `special effect' methods can avoid | |
145 | inheriting its default behaviour and slots. | |
146 | ||
147 | A basic method can be assigned a `role', which may be set either as an | |
148 | initarg or using the :ROLE property. Roles are used for method | |
149 | categorization. | |
150 | ||
151 | The function type protocol is implemented on BASIC-DIRECT-METHOD using | |
152 | slot reader methods. The actual values are computed on demand in methods | |
153 | defined on SLOT-UNBOUND.")) | |
154 | ||
155 | (defmethod shared-initialize :after | |
156 | ((method basic-direct-method) slot-names &key pset) | |
157 | (declare (ignore slot-names)) | |
158 | (default-slot (method 'role) (get-property pset :role :keyword nil))) | |
159 | ||
160 | (defmethod slot-unbound | |
161 | (class (method basic-direct-method) (slot-name (eql 'function-type))) | |
162 | (let ((type (sod-method-type method))) | |
163 | (setf (slot-value method 'function-type) | |
164 | (c-type (fun (lisp (c-type-subtype type)) | |
165 | ("me" (* (class (sod-method-class method)))) | |
166 | . (c-function-arguments type)))))) | |
167 | ||
168 | (defmethod direct-method-function-name ((method basic-direct-method)) | |
169 | (with-slots (class role message) method | |
170 | (format nil "~A__~@[~(~A~)_~]method_~A__~A" class role | |
171 | (sod-class-nickname (sod-message-class message)) | |
172 | (sod-message-name message)))) | |
173 | ||
174 | (defclass daemon-direct-method (basic-direct-method) | |
175 | () | |
176 | (:documentation | |
177 | "A daemon direct method is invoked for side effects and cannot override. | |
178 | ||
179 | This is the direct method class for `before' and `after' methods, which | |
180 | cannot choose to override the remaining methods and are not involved in | |
181 | the computation of the final result. | |
182 | ||
183 | In C terms, a daemon method must return `void', and is not passed a | |
184 | `next_method' pointer.")) | |
185 | ||
186 | (defmethod check-method-type | |
187 | ((method daemon-direct-method) | |
188 | (message sod-message) | |
189 | (type c-function-type)) | |
190 | (with-slots ((msgtype type)) message | |
191 | (unless (c-type-equal-p (c-type-subtype type) (c-type void)) | |
192 | (error "Method return type ~A must be `void'" (c-type-subtype type))) | |
193 | (unless (argument-lists-compatible-p (c-function-arguments msgtype) | |
194 | (c-function-arguments type)) | |
195 | (error "Method arguments ~A don't match message ~A" type msgtype)))) | |
196 | ||
197 | (defclass delegating-direct-method (basic-direct-method) | |
198 | ((next-method-type :type c-function-type | |
199 | :reader sod-method-next-method-type)) | |
200 | (:documentation | |
201 | "A delegating direct method can choose to override other methods. | |
202 | ||
203 | This is the direct method class for `around' and standard-method- | |
204 | combination primary methods, which are given the choice of computing the | |
205 | entire method's result or delegating to (usually) less-specific methods. | |
206 | ||
207 | In C terms, a delegating method is passed a `next_method' pointer so that | |
208 | it can delegate part of its behaviour. (A delegating direct method for a | |
209 | varargs message is also given an additional `va_list' argument, | |
210 | conventionally named `sod__ap_master', which it is expected to pass on to | |
211 | its `next_method' function if necessary.) | |
212 | ||
213 | The function type protocol is implemented on DELEGATING-DIRECT-METHOD | |
214 | using slot reader methods. The actual values are computed on demand in | |
215 | methods defined on SLOT-UNBOUND.")) | |
216 | ||
217 | (defmethod slot-unbound (class | |
218 | (method delegating-direct-method) | |
219 | (slot-name (eql 'next-method-type))) | |
220 | (let* ((message (sod-method-message method)) | |
221 | (type (sod-message-type message))) | |
222 | (setf (slot-value method 'next-method-type) | |
223 | (c-type (fun (lisp (c-type-subtype type)) | |
224 | ("me" (* (class (sod-method-class method)))) | |
225 | . (c-function-arguments type)))))) | |
226 | ||
227 | (defmethod slot-unbound (class | |
228 | (method delegating-direct-method) | |
229 | (slot-name (eql 'function-type))) | |
230 | (let* ((message (sod-method-message method)) | |
231 | (type (sod-method-type method)) | |
232 | (method-args (c-function-arguments type))) | |
233 | (setf (slot-value method 'function-type) | |
234 | (c-type (fun (lisp (c-type-subtype type)) | |
235 | ("me" (* (class (sod-method-class method)))) | |
236 | ("next_method" (* (lisp (commentify-function-type | |
237 | (sod-method-next-method-type | |
238 | method))))) | |
239 | . (if (varargs-message-p message) | |
240 | (cons (make-argument *sod-master-ap* | |
241 | (c-type va-list)) | |
242 | method-args) | |
243 | method-args)))))) | |
244 | ||
245 | ;;;-------------------------------------------------------------------------- | |
246 | ;;; Effective method classes. | |
247 | ||
248 | (defgeneric effective-method-basic-argument-names (method) | |
249 | (:documentation | |
250 | "Return a list of argument names to be passed to direct methods. | |
251 | ||
252 | The argument names are constructed from the message's arguments returned | |
253 | by SOD-MESSAGE-NO-VARARGS-TAIL. The basic arguments are the ones | |
254 | immediately derived from the programmer's explicitly stated arguments; the | |
255 | `me' argument is not included, and neither are more exotic arguments added | |
256 | as part of the method delegation protocol.")) | |
257 | ||
258 | (defclass basic-effective-method (effective-method) | |
259 | ((around-methods :initarg :around-methods | |
260 | :initform nil | |
261 | :type list | |
262 | :reader effective-method-around-methods) | |
263 | (before-methods :initarg :before-methods | |
264 | :initform nil | |
265 | :type list | |
266 | :reader effective-method-before-methods) | |
267 | (after-methods :initarg :after-methods | |
268 | :initform nil | |
269 | :type list | |
270 | :reader effective-method-after-methods) | |
271 | (basic-argument-names :type list | |
272 | :reader effective-method-basic-argument-names) | |
273 | (functions :type list :reader effective-method-functions)) | |
274 | (:documentation | |
275 | "Base class for built-in effective method classes. | |
276 | ||
277 | This class maintains lists of the applicable `before', `after' and | |
278 | `around' methods and provides behaviour for invoking these methods | |
279 | correctly. | |
280 | ||
281 | The argument names protocol is implemented on BASIC-EFFECTIVE-METHOD using | |
282 | a slot reader method. The actual values are computed on demand in methods | |
283 | defined on SLOT-UNBOUND.")) | |
284 | ||
285 | (defmethod slot-unbound (class | |
286 | (method basic-effective-method) | |
287 | (slot-name (eql 'basic-argument-names))) | |
288 | (let ((message (effective-method-message method))) | |
289 | (setf (slot-value method 'basic-argument-names) | |
290 | (subst *sod-master-ap* *sod-ap* | |
291 | (mapcar #'argument-name | |
292 | (sod-message-no-varargs-tail message)))))) | |
293 | ||
294 | ;;;-------------------------------------------------------------------------- | |
295 | ;;; Method categorization. | |
296 | ||
297 | (defmacro categorize ((itemvar items &key bind) categories &body body) | |
298 | "Categorize ITEMS into lists and invoke BODY. | |
299 | ||
300 | The ITEMVAR is a symbol; as the macro iterates over the ITEMS, ITEMVAR | |
301 | will contain the current item. The BIND argument is a list of LET*-like | |
302 | clauses. The CATEGORIES are a list of clauses of the form (SYMBOL | |
303 | PREDICATE). | |
304 | ||
305 | The behaviour of the macro is as follows. ITEMVAR is assigned (not | |
306 | bound), in turn, each item in the list ITEMS. The PREDICATEs in the | |
307 | CATEGORIES list are evaluated in turn, in an environment containing | |
308 | ITEMVAR and the BINDings, until one of them evaluates to a non-nil value. | |
309 | At this point, the item is assigned to the category named by the | |
310 | corresponding SYMBOL. If none of the PREDICATEs returns non-nil then an | |
311 | error is signalled; a PREDICATE consisting only of T will (of course) | |
312 | match anything; it is detected specially so as to avoid compiler warnings. | |
313 | ||
314 | Once all of the ITEMS have been categorized in this fashion, the BODY is | |
315 | evaluated as an implicit PROGN. For each SYMBOL naming a category, a | |
316 | variable named after that symbol will be bound in the BODY's environment | |
317 | to a list of the items in that category, in the same order in which they | |
318 | were found in the list ITEMS. The final values of the macro are the final | |
319 | values of the BODY." | |
320 | ||
321 | (let* ((cat-names (mapcar #'car categories)) | |
322 | (cat-match-forms (mapcar #'cadr categories)) | |
323 | (cat-vars (mapcar (lambda (name) (gensym (symbol-name name))) | |
324 | cat-names)) | |
325 | (items-var (gensym "ITEMS"))) | |
326 | `(let ((,items-var ,items) | |
327 | ,@(mapcar (lambda (cat-var) (list cat-var nil)) cat-vars)) | |
328 | (dolist (,itemvar ,items-var) | |
329 | (let* ,bind | |
330 | (cond ,@(mapcar (lambda (cat-match-form cat-var) | |
331 | `(,cat-match-form | |
332 | (push ,itemvar ,cat-var))) | |
333 | cat-match-forms cat-vars) | |
334 | ,@(and (not (member t cat-match-forms)) | |
335 | `((t (error "Failed to categorize ~A" ,itemvar))))))) | |
336 | (let ,(mapcar (lambda (name var) | |
337 | `(,name (nreverse ,var))) | |
338 | cat-names cat-vars) | |
339 | ,@body)))) | |
340 | ||
341 | ;;;-------------------------------------------------------------------------- | |
342 | ;;; Code generation. | |
343 | ||
344 | (defclass method-codegen (codegen) | |
345 | ((message :initarg :message :type sod-message :reader codegen-message) | |
346 | (class :initarg :class :type sod-class :reader codegen-class) | |
347 | (method :initarg :method :type effective-method :reader codegen-method) | |
348 | (target :initarg :target :reader codegen-target)) | |
349 | (:documentation | |
350 | "Augments CODEGEN with additional state regarding an effective method. | |
351 | ||
352 | We store the effective method, and also its target class and owning | |
353 | message, so that these values are readily available to the code-generating | |
354 | functions.")) | |
355 | ||
356 | (defmethod shared-initialize :after | |
357 | ((codegen method-codegen) slot-names &key) | |
358 | (with-slots (message target) codegen | |
359 | (setf target | |
360 | (if (eq (c-type-subtype (sod-message-type message)) (c-type void)) | |
361 | :void | |
362 | :return)))) | |
363 | ||
364 | (defgeneric compute-effective-method-body (method codegen target) | |
365 | (:documentation | |
366 | "Generates the body of an effective method. | |
367 | ||
368 | Writes the function body to the code generator. It can (obviously) | |
369 | generate auxiliary functions if it needs to. | |
370 | ||
371 | The arguments are as specified by the SOD-MESSAGE-NO-VARARGS-TAIL, with an | |
372 | additional argument `sod__obj' of type pointer-to-ilayout. The code | |
373 | should deliver the result (if any) to the TARGET.")) | |
374 | ||
375 | (defun invoke-method (codegen target arguments-tail direct-method) | |
376 | "Emit code to invoke DIRECT-METHOD, passing it ARGUMENTS-TAIL. | |
377 | ||
378 | The code is generated in the context of CODEGEN, which can be any instance | |
379 | of the CODEGEN class -- it needn't be an instance of METHOD-CODEGEN. The | |
380 | DIRECT-METHOD is called with the given ARGUMENTS-TAIL (a list of argument | |
381 | expressions), preceded by a `me' argument of type pointer-to-CLASS where | |
382 | CLASS is the class on which the method was defined. | |
383 | ||
384 | If the message accepts a variable-length argument list then a copy of the | |
385 | prevailing master argument pointer is provided in place of the :ELLIPSIS." | |
386 | ||
387 | (let* ((message (sod-method-message direct-method)) | |
388 | (class (sod-method-class direct-method)) | |
389 | (function (direct-method-function-name direct-method)) | |
390 | (arguments (cons (format nil "(~A *)&sod__obj.~A" class | |
391 | (sod-class-nickname | |
392 | (sod-class-chain-head class))) | |
393 | arguments-tail))) | |
394 | (if (varargs-message-p message) | |
395 | (convert-stmts codegen target | |
396 | (c-type-subtype (sod-method-type direct-method)) | |
397 | (lambda (var) | |
398 | (ensure-var codegen *sod-ap* (c-type va-list)) | |
399 | (emit-inst codegen | |
400 | (make-va-copy-inst *sod-ap* | |
401 | *sod-master-ap*)) | |
402 | (deliver-expr codegen var | |
403 | (make-call-inst function arguments)) | |
404 | (emit-inst codegen | |
405 | (make-va-end-inst *sod-ap*)))) | |
406 | (deliver-expr codegen target (make-call-inst function arguments))))) | |
407 | ||
408 | (definst convert-to-ilayout (stream) (class chain-head expr) | |
409 | (format stream "SOD_ILAYOUT(~@<~A, ~_~A, ~_~A~:>)" | |
410 | class (sod-class-nickname chain-head) expr)) | |
411 | ||
412 | (defun ensure-ilayout-var (codegen super) | |
413 | "Define a variable `sod__obj' pointing to the class's ilayout structure. | |
414 | ||
415 | CODEGEN is a METHOD-CODEGEN. The class in question is CODEGEN's class, | |
416 | i.e., the target class for the effective method. SUPER is one of the | |
417 | class's superclasses; it is assumed that `me' is a pointer to a SUPER | |
418 | (i.e., to SUPER's ichain within the ilayout)." | |
419 | ||
420 | (let* ((class (codegen-class codegen)) | |
421 | (super-head (sod-class-chain-head super))) | |
422 | (ensure-var codegen "sod__obj" | |
423 | (c-type (* (struct (ilayout-struct-tag class)))) | |
424 | (make-convert-to-ilayout-inst class super-head "me")))) | |
425 | ||
426 | (defun make-trampoline (codegen super body) | |
427 | "Construct a trampoline function and return its name. | |
428 | ||
429 | CODEGEN is a METHOD-CODEGEN. SUPER is a superclass of the CODEGEN class. | |
430 | We construct a new trampoline function (with an unimaginative name) | |
431 | suitable for being passed to a direct method defined on SUPER as its | |
432 | `next_method'. In particular, it will have a `me' argument whose type is | |
433 | pointer-to-SUPER. | |
434 | ||
435 | The code of the function is generated by BODY, which will be invoked with | |
436 | a single argument which is the TARGET to which it should deliver its | |
437 | result. | |
438 | ||
439 | The return value is the name of the generated function." | |
440 | ||
441 | (let* ((message (codegen-message codegen)) | |
442 | (message-type (sod-message-type message)) | |
443 | (return-type (c-type-subtype message-type)) | |
444 | (arguments (mapcar (lambda (arg) | |
445 | (if (eq (argument-name arg) *sod-ap*) | |
446 | (make-argument *sod-master-ap* | |
447 | (c-type va-list)) | |
448 | arg)) | |
449 | (sod-message-no-varargs-tail message)))) | |
450 | (codegen-push codegen) | |
451 | (ensure-ilayout-var codegen super) | |
452 | (funcall body (codegen-target codegen)) | |
453 | (codegen-pop-function codegen (temporary-function) | |
454 | (c-type (fun (lisp return-type) | |
455 | ("me" (* (class super))) | |
456 | . arguments)))))) | |
457 | ||
458 | (defun invoke-delegation-chain (codegen target basic-tail chain kernel) | |
459 | "Invoke a chain of delegating methods. | |
460 | ||
461 | CODEGEN is a METHOD-CODEGEN. BASIC-TAIL is a list of argument expressions | |
462 | to provide to the methods. The result of the delegation chain will be | |
463 | delivered to TARGET. | |
464 | ||
465 | The CHAIN is a list of DELEGATING-DIRECT-METHOD objects. The behaviour is | |
466 | as follows. The first method in the chain is invoked with the necessary | |
467 | arguments (see below) including a `next_method' pointer. If KERNEL is nil | |
468 | and there are no more methods in the chain then the `next_method' pointer | |
469 | will be null; otherwise it will point to a `trampoline' function, whose | |
470 | behaviour is to call the remaining methods on the chain as a delegation | |
471 | chain. The method may choose to call this function with its arguments. | |
472 | It will finally return a value, which will be delivered to the TARGET. | |
473 | ||
474 | If the chain is empty, then the code generated by KERNEL (given a TARGET | |
475 | argument) will be invoked. It is an error if both CHAIN and KERNEL are | |
476 | nil." | |
477 | ||
478 | (let* ((message (codegen-message codegen)) | |
479 | (argument-tail (if (varargs-message-p message) | |
480 | (cons *sod-master-ap* basic-tail) | |
481 | basic-tail))) | |
482 | (labels ((next-trampoline (method chain) | |
483 | (if (or kernel chain) | |
484 | (make-trampoline codegen (sod-method-class method) | |
485 | (lambda (target) | |
486 | (invoke chain target))) | |
487 | 0)) | |
488 | (invoke (chain target) | |
489 | (if (null chain) | |
490 | (funcall kernel target) | |
491 | (let* ((trampoline (next-trampoline (car chain) | |
492 | (cdr chain)))) | |
493 | (invoke-method codegen target | |
494 | (cons trampoline argument-tail) | |
495 | (car chain)))))) | |
496 | (invoke chain target)))) | |
497 | ||
498 | (defun basic-effective-method-body (codegen target method body) | |
499 | "Build the common method-invocation structure. | |
500 | ||
501 | Writes to CODEGEN some basic method-invocation instructions. It invokes | |
502 | the `around' methods, from most- to least-specific. If they all delegate, | |
503 | then the `before' methods are run, most-specific first; next, the | |
504 | instructions generated by BODY (invoked with a target argument); then, the | |
505 | `after' methods are run, least-specific first; and, finally, the value | |
506 | delivered by the BODY is returned to the `around' methods. The result | |
507 | returned by the outermost `around' method -- or, if there are none, | |
508 | delivered by the BODY -- is finally delivered to the TARGET." | |
509 | ||
510 | (with-slots (message class before-methods after-methods around-methods) | |
511 | method | |
512 | (let* ((message-type (sod-message-type message)) | |
513 | (return-type (c-type-subtype message-type)) | |
514 | (voidp (eq return-type (c-type void))) | |
515 | (basic-tail (effective-method-basic-argument-names method))) | |
516 | (flet ((method-kernel (target) | |
517 | (dolist (before before-methods) | |
518 | (invoke-method codegen :void basic-tail before)) | |
519 | (if (or voidp (null after-methods)) | |
520 | (funcall body target) | |
521 | (convert-stmts codegen target return-type | |
522 | (lambda (target) | |
523 | (funcall body target) | |
524 | (dolist (after (reverse after-methods)) | |
525 | (invoke-method codegen :void | |
526 | after basic-tail))))))) | |
527 | (invoke-delegation-chain codegen target basic-tail | |
528 | around-methods #'method-kernel))))) | |
529 | ||
530 | ;;;-------------------------------------------------------------------------- | |
531 | ;;; Effective method entry points. | |
532 | ||
533 | (defgeneric compute-method-entry-functions (method) | |
534 | (:documentation | |
535 | "Construct method entry functions. | |
536 | ||
537 | Builds the effective method function (if there is one) and the necessary | |
538 | method entries. Returns a list of functions (i.e., FUNCTION-INST objects) | |
539 | which need to be defined in the generated source code.")) | |
540 | ||
541 | (defparameter *method-entry-inline-threshold* 20 | |
542 | "Threshold below which effective method bodies are inlined into entries. | |
543 | ||
544 | After the effective method body has been computed, we calculate its | |
545 | metric, multiply by the number of entries we need to generate, and compare | |
546 | it with this threshold. If the metric is below the threshold then we | |
547 | fold the method body into the entry functions; otherwise we split the | |
548 | effective method out into its own function.") | |
549 | ||
550 | (defgeneric effective-method-function-name (method) | |
551 | (:documentation | |
552 | "Returns the function name of an effective method.")) | |
553 | ||
554 | (defgeneric method-entry-function-name (method chain-head) | |
555 | (:documentation | |
556 | "Returns the function name of a method entry. | |
557 | ||
558 | The method entry is given as an effective method/chain-head pair, rather | |
559 | than as a method entry object because we want the function name before | |
560 | we've made the entry object.")) | |
561 | ||
562 | (defmethod effective-method-function-name ((method effective-method)) | |
563 | (let* ((class (effective-method-class method)) | |
564 | (message (effective-method-message method)) | |
565 | (message-class (sod-message-class message))) | |
566 | (format nil "~A__emethod_~A__~A" | |
567 | class | |
568 | (sod-class-nickname message-class) | |
569 | (sod-message-name message)))) | |
570 | ||
571 | (defmethod method-entry-function-name | |
572 | ((method effective-method) (chain-head sod-class)) | |
573 | (let* ((class (effective-method-class method)) | |
574 | (message (effective-method-message method)) | |
575 | (message-class (sod-message-class message))) | |
576 | (format nil "~A__mentry_~A__~A__~A" | |
577 | class | |
578 | (sod-class-nickname message-class) | |
579 | (sod-message-name message) | |
580 | (sod-class-nickname chain-head)))) | |
581 | ||
582 | (defmethod compute-method-entry-functions ((method basic-effective-method)) | |
583 | ||
584 | ;; OK, there's quite a lot of this, so hold tight. | |
585 | ;; | |
586 | ;; The first thing we need to do is find all of the related objects. This | |
587 | ;; is a bit verbose but fairly straightforward. | |
588 | ;; | |
589 | ;; Next, we generate the effective method body -- using COMPUTE-EFFECTIVE- | |
590 | ;; METHOD-BODY of all things. This gives us the declarations and body for | |
591 | ;; an effective method function, but we don't have an actual function yet. | |
592 | ;; | |
593 | ;; Now we look at the chains which are actually going to need a method | |
594 | ;; entry: only those chains whose tail (most specific) class is a | |
595 | ;; superclass of the class which defined the message need an entry. We | |
596 | ;; build a list of these tail classes. | |
597 | ;; | |
598 | ;; Having done this, we decide whether it's better to generate a standalone | |
599 | ;; effective-method function and call it from each of the method entries, | |
600 | ;; or to inline the effective method body into each of the entries. | |
601 | ;; | |
602 | ;; Most of the complexity here comes from (a) dealing with the two | |
603 | ;; different strategies for constructing method entry functions and (b) | |
604 | ;; (unsurprisingly) the mess involved with dealing with varargs messages. | |
605 | ||
606 | (let* ((message (effective-method-message method)) | |
607 | (class (effective-method-class method)) | |
608 | (message-class (sod-message-class message)) | |
609 | (return-type (c-type-subtype (sod-message-type message))) | |
610 | (codegen (make-instance 'method-codegen | |
611 | :message message | |
612 | :class class | |
613 | :method method)) | |
614 | ||
615 | ;; Effective method function details. | |
616 | (emf-name (effective-method-function-name method)) | |
617 | (ilayout-type (c-type (* (struct (ilayout-struct-tag class))))) | |
618 | (emf-arg-tail (mapcar (lambda (arg) | |
619 | (if (eq (argument-name arg) *sod-ap*) | |
620 | (make-argument *sod-master-ap* | |
621 | (c-type va-list)) | |
622 | arg)) | |
623 | (sod-message-no-varargs-tail message))) | |
624 | (emf-type (c-type (fun (lisp return-type) | |
625 | ("sod__obj" (lisp ilayout-type)) | |
626 | . (sod-message-no-varargs-tail message)))) | |
627 | (result (if (eq return-type (c-type void)) nil | |
628 | (temporary-var codegen return-type))) | |
629 | (emf-target (or result :void)) | |
630 | ||
631 | ;; Method entry details. | |
632 | (chain-tails (remove-if-not (lambda (super) | |
633 | (sod-subclass-p super message-class)) | |
634 | (mapcar #'car | |
635 | (sod-class-chains class)))) | |
636 | (n-entries (length chain-tails)) | |
637 | (entry-args (sod-message-argument-tail message)) | |
638 | (parm-n (do ((prev "me" (car args)) | |
639 | (args entry-args (cdr args))) | |
640 | ((endp args) nil) | |
641 | (when (eq (car args) :ellipsis) | |
642 | (return prev)))) | |
643 | (entry-target (codegen-target codegen))) | |
644 | ||
645 | (labels ((setup-entry (tail) | |
646 | (let ((head (sod-class-chain-head tail))) | |
647 | (codegen-push codegen) | |
648 | (ensure-var codegen "sod__obj" ilayout-type | |
649 | (make-convert-to-ilayout-inst class | |
650 | head "me")))) | |
651 | (varargs-prologue () | |
652 | (ensure-var codegen *sod-master-ap* (c-type va-list)) | |
653 | (emit-inst codegen | |
654 | (make-va-start-inst *sod-master-ap* parm-n))) | |
655 | (varargs-epilogue () | |
656 | (emit-inst codegen (make-va-end-inst *sod-master-ap*))) | |
657 | (finish-entry (tail) | |
658 | (let* ((head (sod-class-chain-head tail)) | |
659 | (name (method-entry-function-name method head)) | |
660 | (type (c-type (fun (lisp return-type) | |
661 | ("me" (* (class tail))) | |
662 | . entry-args)))) | |
663 | (codegen-pop-function codegen name type)))) | |
664 | ||
665 | ;; Generate the method body. We'll work out what to do with it later. | |
666 | (codegen-push codegen) | |
667 | (compute-effective-method-body method codegen emf-target) | |
668 | (multiple-value-bind (vars insts) (codegen-pop codegen) | |
669 | (cond ((or (= n-entries 1) | |
670 | (<= (* n-entries (reduce #'+ insts :key #'inst-metric)) | |
671 | *method-entry-inline-threshold*)) | |
672 | ||
673 | ;; The effective method body is simple -- or there's only one | |
674 | ;; of them. We'll inline the method body into the entry | |
675 | ;; functions. | |
676 | (dolist (tail chain-tails) | |
677 | (setup-entry tail) | |
678 | (dolist (var vars) | |
679 | (ensure-var codegen (inst-name var) | |
680 | (inst-type var) (inst-init var))) | |
681 | (when parm-n (varargs-prologue)) | |
682 | (emit-insts codegen insts) | |
683 | (when parm-n (varargs-epilogue)) | |
684 | (deliver-expr codegen entry-target result) | |
685 | (finish-entry tail))) | |
686 | ||
687 | (t | |
688 | ||
689 | ;; The effective method body is complicated and we'd need more | |
690 | ;; than one copy. We'll generate an effective method function | |
691 | ;; and call it a lot. | |
692 | (codegen-build-function codegen emf-name emf-type vars | |
693 | (nconc insts (and result (list (make-return-inst result))))) | |
694 | ||
695 | (let ((call (make-call-inst emf-name | |
696 | (cons "sod__obj" (mapcar #'argument-name | |
697 | emf-arg-tail))))) | |
698 | (dolist (tail chain-tails) | |
699 | (setup-entry tail) | |
700 | (cond (parm-n | |
701 | (varargs-prologue) | |
702 | (convert-stmts codegen entry-target return-type | |
703 | (lambda (target) | |
704 | (deliver-expr codegen target call) | |
705 | (varargs-epilogue)))) | |
706 | (t | |
707 | (deliver-expr codegen entry-target call))) | |
708 | (finish-entry tail)))))) | |
709 | ||
710 | (codegen-functions codegen)))) | |
711 | ||
712 | (defmethod slot-unbound | |
713 | (class (method basic-effective-method) (slot-name (eql 'functions))) | |
714 | (setf (slot-value method 'functions) | |
715 | (compute-method-entry-functions method))) | |
716 | ||
717 | (defmethod make-method-entry | |
718 | ((method basic-effective-method) (chain-head sod-class)) | |
719 | (make-instance 'method-entry :method method :chain-head chain-head)) | |
720 | ||
721 | ;;;----- That's all, folks -------------------------------------------------- |