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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 | ||
ddee4bb1 | 45 | (defgeneric sod-method-function-type (method) |
1f1d88f5 MW |
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 | ||
ddee4bb1 | 56 | (defgeneric sod-method-next-method-type (method) |
1f1d88f5 MW |
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 | ||
ddee4bb1 | 67 | (defgeneric sod-method-function-name (method) |
1f1d88f5 MW |
68 | (:documentation |
69 | "Return the C function name for the direct method.")) | |
70 | ||
ddee4bb1 MW |
71 | (defgeneric method-entry-function-type (entry) |
72 | (:documentation | |
73 | "Return the C function type for a method entry.")) | |
74 | ||
1f1d88f5 MW |
75 | ;;;-------------------------------------------------------------------------- |
76 | ;;; Message classes. | |
77 | ||
78 | (defclass basic-message (sod-message) | |
79 | ((argument-tail :type list :reader sod-message-argument-tail) | |
80 | (no-varargs-tail :type list :reader sod-message-no-varargs-tail)) | |
81 | (:documentation | |
82 | "Base class for built-in message classes. | |
83 | ||
84 | Provides the basic functionality for the built-in method combinations. | |
85 | This is a separate class so that `special effect' messages can avoid | |
86 | inheriting its default behaviour. | |
87 | ||
88 | The function type protocol is implemented on BASIC-MESSAGE using slot | |
89 | reader methods. The actual values are computed on demand in methods | |
90 | defined on SLOT-UNBOUND.")) | |
91 | ||
92 | ;;; Function type protocol. | |
93 | ||
94 | (defmethod slot-unbound (class | |
95 | (message basic-message) | |
96 | (slot-name (eql 'argument-tail))) | |
97 | (let ((seq 0)) | |
98 | (mapcar (lambda (arg) | |
99 | (if (or (eq arg :ellipsis) (argument-name arg)) | |
100 | arg | |
101 | (make-argument (make-instance 'temporary-argument | |
102 | :tag (prog1 seq (incf seq))) | |
103 | (argument-type arg)))) | |
104 | (c-function-arguments (sod-message-type message))))) | |
105 | ||
106 | (defmethod slot-unbound (class | |
107 | (message basic-message) | |
108 | (slot-name (eql 'no-varargs-tail))) | |
109 | (mapcar (lambda (arg) | |
110 | (if (eq arg :ellipsis) | |
111 | (make-argument *sod-ap* (c-type va-list)) | |
112 | arg)) | |
113 | (sod-message-argument-tail message))) | |
114 | ||
115 | ;;; Method class selection. | |
116 | ||
117 | (defmethod sod-message-method-class | |
118 | ((message basic-message) (class sod-class) pset) | |
119 | (let ((role (get-property pset :role :keyword nil))) | |
120 | (case role | |
121 | ((:before :after) 'daemon-direct-method) | |
122 | (:around 'delegating-direct-method) | |
123 | ((nil) (error "How odd: a primary method slipped through the net")) | |
124 | (t (error "Unknown method role ~A" role))))) | |
125 | ||
126 | ;;; Utility functions. | |
127 | ||
128 | (defun varargs-message-p (message) | |
129 | "Answer whether the MESSAGE accepts a variable-length argument list. | |
130 | ||
131 | We need to jump through some extra hoops in order to cope with varargs | |
132 | messages, so this is useful to know." | |
133 | (member :ellipsis (sod-message-argument-tail message))) | |
134 | ||
135 | ;;;-------------------------------------------------------------------------- | |
136 | ;;; Direct method classes. | |
137 | ||
138 | (defclass basic-direct-method (sod-method) | |
77027cca MW |
139 | ((role :initarg :role :type symbol :reader sod-method-role) |
140 | (function-type :type c-function-type :reader sod-method-function-type)) | |
1f1d88f5 MW |
141 | (:documentation |
142 | "Base class for built-in direct method classes. | |
143 | ||
144 | Provides the basic functionality for the built-in direct-method classes. | |
145 | This is a separate class so that `special effect' methods can avoid | |
146 | inheriting its default behaviour and slots. | |
147 | ||
148 | A basic method can be assigned a `role', which may be set either as an | |
149 | initarg or using the :ROLE property. Roles are used for method | |
150 | categorization. | |
151 | ||
152 | The function type protocol is implemented on BASIC-DIRECT-METHOD using | |
153 | slot reader methods. The actual values are computed on demand in methods | |
154 | defined on SLOT-UNBOUND.")) | |
155 | ||
156 | (defmethod shared-initialize :after | |
157 | ((method basic-direct-method) slot-names &key pset) | |
158 | (declare (ignore slot-names)) | |
159 | (default-slot (method 'role) (get-property pset :role :keyword nil))) | |
160 | ||
161 | (defmethod slot-unbound | |
162 | (class (method basic-direct-method) (slot-name (eql 'function-type))) | |
163 | (let ((type (sod-method-type method))) | |
164 | (setf (slot-value method 'function-type) | |
165 | (c-type (fun (lisp (c-type-subtype type)) | |
166 | ("me" (* (class (sod-method-class method)))) | |
167 | . (c-function-arguments type)))))) | |
168 | ||
ddee4bb1 | 169 | (defmethod sod-method-function-name ((method basic-direct-method)) |
1f1d88f5 MW |
170 | (with-slots (class role message) method |
171 | (format nil "~A__~@[~(~A~)_~]method_~A__~A" class role | |
172 | (sod-class-nickname (sod-message-class message)) | |
173 | (sod-message-name message)))) | |
174 | ||
175 | (defclass daemon-direct-method (basic-direct-method) | |
176 | () | |
177 | (:documentation | |
178 | "A daemon direct method is invoked for side effects and cannot override. | |
179 | ||
180 | This is the direct method class for `before' and `after' methods, which | |
181 | cannot choose to override the remaining methods and are not involved in | |
182 | the computation of the final result. | |
183 | ||
184 | In C terms, a daemon method must return `void', and is not passed a | |
185 | `next_method' pointer.")) | |
186 | ||
187 | (defmethod check-method-type | |
188 | ((method daemon-direct-method) | |
189 | (message sod-message) | |
190 | (type c-function-type)) | |
191 | (with-slots ((msgtype type)) message | |
192 | (unless (c-type-equal-p (c-type-subtype type) (c-type void)) | |
193 | (error "Method return type ~A must be `void'" (c-type-subtype type))) | |
194 | (unless (argument-lists-compatible-p (c-function-arguments msgtype) | |
195 | (c-function-arguments type)) | |
196 | (error "Method arguments ~A don't match message ~A" type msgtype)))) | |
197 | ||
198 | (defclass delegating-direct-method (basic-direct-method) | |
199 | ((next-method-type :type c-function-type | |
200 | :reader sod-method-next-method-type)) | |
201 | (:documentation | |
202 | "A delegating direct method can choose to override other methods. | |
203 | ||
204 | This is the direct method class for `around' and standard-method- | |
205 | combination primary methods, which are given the choice of computing the | |
206 | entire method's result or delegating to (usually) less-specific methods. | |
207 | ||
208 | In C terms, a delegating method is passed a `next_method' pointer so that | |
209 | it can delegate part of its behaviour. (A delegating direct method for a | |
210 | varargs message is also given an additional `va_list' argument, | |
211 | conventionally named `sod__ap_master', which it is expected to pass on to | |
212 | its `next_method' function if necessary.) | |
213 | ||
214 | The function type protocol is implemented on DELEGATING-DIRECT-METHOD | |
215 | using slot reader methods. The actual values are computed on demand in | |
216 | methods defined on SLOT-UNBOUND.")) | |
217 | ||
218 | (defmethod slot-unbound (class | |
219 | (method delegating-direct-method) | |
220 | (slot-name (eql 'next-method-type))) | |
221 | (let* ((message (sod-method-message method)) | |
222 | (type (sod-message-type message))) | |
223 | (setf (slot-value method 'next-method-type) | |
224 | (c-type (fun (lisp (c-type-subtype type)) | |
225 | ("me" (* (class (sod-method-class method)))) | |
226 | . (c-function-arguments type)))))) | |
227 | ||
228 | (defmethod slot-unbound (class | |
229 | (method delegating-direct-method) | |
230 | (slot-name (eql 'function-type))) | |
231 | (let* ((message (sod-method-message method)) | |
232 | (type (sod-method-type method)) | |
233 | (method-args (c-function-arguments type))) | |
234 | (setf (slot-value method 'function-type) | |
235 | (c-type (fun (lisp (c-type-subtype type)) | |
236 | ("me" (* (class (sod-method-class method)))) | |
237 | ("next_method" (* (lisp (commentify-function-type | |
238 | (sod-method-next-method-type | |
239 | method))))) | |
240 | . (if (varargs-message-p message) | |
241 | (cons (make-argument *sod-master-ap* | |
242 | (c-type va-list)) | |
243 | method-args) | |
244 | method-args)))))) | |
245 | ||
246 | ;;;-------------------------------------------------------------------------- | |
247 | ;;; Effective method classes. | |
248 | ||
249 | (defgeneric effective-method-basic-argument-names (method) | |
250 | (:documentation | |
251 | "Return a list of argument names to be passed to direct methods. | |
252 | ||
253 | The argument names are constructed from the message's arguments returned | |
254 | by SOD-MESSAGE-NO-VARARGS-TAIL. The basic arguments are the ones | |
255 | immediately derived from the programmer's explicitly stated arguments; the | |
256 | `me' argument is not included, and neither are more exotic arguments added | |
257 | as part of the method delegation protocol.")) | |
258 | ||
259 | (defclass basic-effective-method (effective-method) | |
77027cca MW |
260 | ((around-methods :initarg :around-methods :initform nil |
261 | :type list :reader effective-method-around-methods) | |
262 | (before-methods :initarg :before-methods :initform nil | |
263 | :type list :reader effective-method-before-methods) | |
264 | (after-methods :initarg :after-methods :initform nil | |
265 | :type list :reader effective-method-after-methods) | |
1f1d88f5 MW |
266 | (basic-argument-names :type list |
267 | :reader effective-method-basic-argument-names) | |
268 | (functions :type list :reader effective-method-functions)) | |
269 | (:documentation | |
270 | "Base class for built-in effective method classes. | |
271 | ||
272 | This class maintains lists of the applicable `before', `after' and | |
273 | `around' methods and provides behaviour for invoking these methods | |
274 | correctly. | |
275 | ||
276 | The argument names protocol is implemented on BASIC-EFFECTIVE-METHOD using | |
277 | a slot reader method. The actual values are computed on demand in methods | |
278 | defined on SLOT-UNBOUND.")) | |
279 | ||
280 | (defmethod slot-unbound (class | |
281 | (method basic-effective-method) | |
282 | (slot-name (eql 'basic-argument-names))) | |
283 | (let ((message (effective-method-message method))) | |
284 | (setf (slot-value method 'basic-argument-names) | |
285 | (subst *sod-master-ap* *sod-ap* | |
286 | (mapcar #'argument-name | |
287 | (sod-message-no-varargs-tail message)))))) | |
288 | ||
289 | ;;;-------------------------------------------------------------------------- | |
290 | ;;; Method categorization. | |
291 | ||
292 | (defmacro categorize ((itemvar items &key bind) categories &body body) | |
293 | "Categorize ITEMS into lists and invoke BODY. | |
294 | ||
295 | The ITEMVAR is a symbol; as the macro iterates over the ITEMS, ITEMVAR | |
296 | will contain the current item. The BIND argument is a list of LET*-like | |
297 | clauses. The CATEGORIES are a list of clauses of the form (SYMBOL | |
298 | PREDICATE). | |
299 | ||
300 | The behaviour of the macro is as follows. ITEMVAR is assigned (not | |
301 | bound), in turn, each item in the list ITEMS. The PREDICATEs in the | |
302 | CATEGORIES list are evaluated in turn, in an environment containing | |
303 | ITEMVAR and the BINDings, until one of them evaluates to a non-nil value. | |
304 | At this point, the item is assigned to the category named by the | |
305 | corresponding SYMBOL. If none of the PREDICATEs returns non-nil then an | |
306 | error is signalled; a PREDICATE consisting only of T will (of course) | |
307 | match anything; it is detected specially so as to avoid compiler warnings. | |
308 | ||
309 | Once all of the ITEMS have been categorized in this fashion, the BODY is | |
310 | evaluated as an implicit PROGN. For each SYMBOL naming a category, a | |
311 | variable named after that symbol will be bound in the BODY's environment | |
312 | to a list of the items in that category, in the same order in which they | |
313 | were found in the list ITEMS. The final values of the macro are the final | |
314 | values of the BODY." | |
315 | ||
316 | (let* ((cat-names (mapcar #'car categories)) | |
317 | (cat-match-forms (mapcar #'cadr categories)) | |
318 | (cat-vars (mapcar (lambda (name) (gensym (symbol-name name))) | |
319 | cat-names)) | |
320 | (items-var (gensym "ITEMS"))) | |
321 | `(let ((,items-var ,items) | |
322 | ,@(mapcar (lambda (cat-var) (list cat-var nil)) cat-vars)) | |
323 | (dolist (,itemvar ,items-var) | |
324 | (let* ,bind | |
325 | (cond ,@(mapcar (lambda (cat-match-form cat-var) | |
326 | `(,cat-match-form | |
327 | (push ,itemvar ,cat-var))) | |
328 | cat-match-forms cat-vars) | |
329 | ,@(and (not (member t cat-match-forms)) | |
330 | `((t (error "Failed to categorize ~A" ,itemvar))))))) | |
331 | (let ,(mapcar (lambda (name var) | |
332 | `(,name (nreverse ,var))) | |
333 | cat-names cat-vars) | |
334 | ,@body)))) | |
335 | ||
336 | ;;;-------------------------------------------------------------------------- | |
337 | ;;; Code generation. | |
338 | ||
339 | (defclass method-codegen (codegen) | |
340 | ((message :initarg :message :type sod-message :reader codegen-message) | |
341 | (class :initarg :class :type sod-class :reader codegen-class) | |
342 | (method :initarg :method :type effective-method :reader codegen-method) | |
343 | (target :initarg :target :reader codegen-target)) | |
344 | (:documentation | |
345 | "Augments CODEGEN with additional state regarding an effective method. | |
346 | ||
347 | We store the effective method, and also its target class and owning | |
348 | message, so that these values are readily available to the code-generating | |
349 | functions.")) | |
350 | ||
351 | (defmethod shared-initialize :after | |
352 | ((codegen method-codegen) slot-names &key) | |
353 | (with-slots (message target) codegen | |
354 | (setf target | |
355 | (if (eq (c-type-subtype (sod-message-type message)) (c-type void)) | |
356 | :void | |
357 | :return)))) | |
358 | ||
359 | (defgeneric compute-effective-method-body (method codegen target) | |
360 | (:documentation | |
361 | "Generates the body of an effective method. | |
362 | ||
363 | Writes the function body to the code generator. It can (obviously) | |
364 | generate auxiliary functions if it needs to. | |
365 | ||
366 | The arguments are as specified by the SOD-MESSAGE-NO-VARARGS-TAIL, with an | |
367 | additional argument `sod__obj' of type pointer-to-ilayout. The code | |
368 | should deliver the result (if any) to the TARGET.")) | |
369 | ||
370 | (defun invoke-method (codegen target arguments-tail direct-method) | |
371 | "Emit code to invoke DIRECT-METHOD, passing it ARGUMENTS-TAIL. | |
372 | ||
373 | The code is generated in the context of CODEGEN, which can be any instance | |
374 | of the CODEGEN class -- it needn't be an instance of METHOD-CODEGEN. The | |
375 | DIRECT-METHOD is called with the given ARGUMENTS-TAIL (a list of argument | |
376 | expressions), preceded by a `me' argument of type pointer-to-CLASS where | |
377 | CLASS is the class on which the method was defined. | |
378 | ||
379 | If the message accepts a variable-length argument list then a copy of the | |
380 | prevailing master argument pointer is provided in place of the :ELLIPSIS." | |
381 | ||
382 | (let* ((message (sod-method-message direct-method)) | |
383 | (class (sod-method-class direct-method)) | |
ddee4bb1 | 384 | (function (sod-method-function-name direct-method)) |
1f1d88f5 MW |
385 | (arguments (cons (format nil "(~A *)&sod__obj.~A" class |
386 | (sod-class-nickname | |
387 | (sod-class-chain-head class))) | |
388 | arguments-tail))) | |
389 | (if (varargs-message-p message) | |
390 | (convert-stmts codegen target | |
391 | (c-type-subtype (sod-method-type direct-method)) | |
392 | (lambda (var) | |
393 | (ensure-var codegen *sod-ap* (c-type va-list)) | |
394 | (emit-inst codegen | |
395 | (make-va-copy-inst *sod-ap* | |
396 | *sod-master-ap*)) | |
397 | (deliver-expr codegen var | |
398 | (make-call-inst function arguments)) | |
399 | (emit-inst codegen | |
400 | (make-va-end-inst *sod-ap*)))) | |
401 | (deliver-expr codegen target (make-call-inst function arguments))))) | |
402 | ||
403 | (definst convert-to-ilayout (stream) (class chain-head expr) | |
404 | (format stream "SOD_ILAYOUT(~@<~A, ~_~A, ~_~A~:>)" | |
405 | class (sod-class-nickname chain-head) expr)) | |
406 | ||
407 | (defun ensure-ilayout-var (codegen super) | |
408 | "Define a variable `sod__obj' pointing to the class's ilayout structure. | |
409 | ||
410 | CODEGEN is a METHOD-CODEGEN. The class in question is CODEGEN's class, | |
411 | i.e., the target class for the effective method. SUPER is one of the | |
412 | class's superclasses; it is assumed that `me' is a pointer to a SUPER | |
413 | (i.e., to SUPER's ichain within the ilayout)." | |
414 | ||
415 | (let* ((class (codegen-class codegen)) | |
416 | (super-head (sod-class-chain-head super))) | |
417 | (ensure-var codegen "sod__obj" | |
418 | (c-type (* (struct (ilayout-struct-tag class)))) | |
419 | (make-convert-to-ilayout-inst class super-head "me")))) | |
420 | ||
421 | (defun make-trampoline (codegen super body) | |
422 | "Construct a trampoline function and return its name. | |
423 | ||
424 | CODEGEN is a METHOD-CODEGEN. SUPER is a superclass of the CODEGEN class. | |
425 | We construct a new trampoline function (with an unimaginative name) | |
426 | suitable for being passed to a direct method defined on SUPER as its | |
427 | `next_method'. In particular, it will have a `me' argument whose type is | |
428 | pointer-to-SUPER. | |
429 | ||
430 | The code of the function is generated by BODY, which will be invoked with | |
431 | a single argument which is the TARGET to which it should deliver its | |
432 | result. | |
433 | ||
434 | The return value is the name of the generated function." | |
435 | ||
436 | (let* ((message (codegen-message codegen)) | |
437 | (message-type (sod-message-type message)) | |
438 | (return-type (c-type-subtype message-type)) | |
439 | (arguments (mapcar (lambda (arg) | |
440 | (if (eq (argument-name arg) *sod-ap*) | |
441 | (make-argument *sod-master-ap* | |
442 | (c-type va-list)) | |
443 | arg)) | |
444 | (sod-message-no-varargs-tail message)))) | |
445 | (codegen-push codegen) | |
446 | (ensure-ilayout-var codegen super) | |
447 | (funcall body (codegen-target codegen)) | |
448 | (codegen-pop-function codegen (temporary-function) | |
449 | (c-type (fun (lisp return-type) | |
450 | ("me" (* (class super))) | |
ddee4bb1 | 451 | . arguments))))) |
1f1d88f5 MW |
452 | |
453 | (defun invoke-delegation-chain (codegen target basic-tail chain kernel) | |
454 | "Invoke a chain of delegating methods. | |
455 | ||
456 | CODEGEN is a METHOD-CODEGEN. BASIC-TAIL is a list of argument expressions | |
457 | to provide to the methods. The result of the delegation chain will be | |
458 | delivered to TARGET. | |
459 | ||
460 | The CHAIN is a list of DELEGATING-DIRECT-METHOD objects. The behaviour is | |
461 | as follows. The first method in the chain is invoked with the necessary | |
462 | arguments (see below) including a `next_method' pointer. If KERNEL is nil | |
463 | and there are no more methods in the chain then the `next_method' pointer | |
464 | will be null; otherwise it will point to a `trampoline' function, whose | |
465 | behaviour is to call the remaining methods on the chain as a delegation | |
466 | chain. The method may choose to call this function with its arguments. | |
467 | It will finally return a value, which will be delivered to the TARGET. | |
468 | ||
469 | If the chain is empty, then the code generated by KERNEL (given a TARGET | |
470 | argument) will be invoked. It is an error if both CHAIN and KERNEL are | |
471 | nil." | |
472 | ||
473 | (let* ((message (codegen-message codegen)) | |
474 | (argument-tail (if (varargs-message-p message) | |
475 | (cons *sod-master-ap* basic-tail) | |
476 | basic-tail))) | |
477 | (labels ((next-trampoline (method chain) | |
478 | (if (or kernel chain) | |
479 | (make-trampoline codegen (sod-method-class method) | |
480 | (lambda (target) | |
481 | (invoke chain target))) | |
482 | 0)) | |
483 | (invoke (chain target) | |
484 | (if (null chain) | |
485 | (funcall kernel target) | |
486 | (let* ((trampoline (next-trampoline (car chain) | |
487 | (cdr chain)))) | |
488 | (invoke-method codegen target | |
489 | (cons trampoline argument-tail) | |
490 | (car chain)))))) | |
491 | (invoke chain target)))) | |
492 | ||
493 | (defun basic-effective-method-body (codegen target method body) | |
494 | "Build the common method-invocation structure. | |
495 | ||
496 | Writes to CODEGEN some basic method-invocation instructions. It invokes | |
497 | the `around' methods, from most- to least-specific. If they all delegate, | |
498 | then the `before' methods are run, most-specific first; next, the | |
499 | instructions generated by BODY (invoked with a target argument); then, the | |
500 | `after' methods are run, least-specific first; and, finally, the value | |
501 | delivered by the BODY is returned to the `around' methods. The result | |
502 | returned by the outermost `around' method -- or, if there are none, | |
503 | delivered by the BODY -- is finally delivered to the TARGET." | |
504 | ||
505 | (with-slots (message class before-methods after-methods around-methods) | |
506 | method | |
507 | (let* ((message-type (sod-message-type message)) | |
508 | (return-type (c-type-subtype message-type)) | |
509 | (voidp (eq return-type (c-type void))) | |
510 | (basic-tail (effective-method-basic-argument-names method))) | |
511 | (flet ((method-kernel (target) | |
512 | (dolist (before before-methods) | |
513 | (invoke-method codegen :void basic-tail before)) | |
514 | (if (or voidp (null after-methods)) | |
515 | (funcall body target) | |
516 | (convert-stmts codegen target return-type | |
517 | (lambda (target) | |
518 | (funcall body target) | |
519 | (dolist (after (reverse after-methods)) | |
520 | (invoke-method codegen :void | |
521 | after basic-tail))))))) | |
522 | (invoke-delegation-chain codegen target basic-tail | |
523 | around-methods #'method-kernel))))) | |
524 | ||
525 | ;;;-------------------------------------------------------------------------- | |
526 | ;;; Effective method entry points. | |
527 | ||
528 | (defgeneric compute-method-entry-functions (method) | |
529 | (:documentation | |
530 | "Construct method entry functions. | |
531 | ||
532 | Builds the effective method function (if there is one) and the necessary | |
533 | method entries. Returns a list of functions (i.e., FUNCTION-INST objects) | |
534 | which need to be defined in the generated source code.")) | |
535 | ||
536 | (defparameter *method-entry-inline-threshold* 20 | |
537 | "Threshold below which effective method bodies are inlined into entries. | |
538 | ||
539 | After the effective method body has been computed, we calculate its | |
540 | metric, multiply by the number of entries we need to generate, and compare | |
541 | it with this threshold. If the metric is below the threshold then we | |
542 | fold the method body into the entry functions; otherwise we split the | |
543 | effective method out into its own function.") | |
544 | ||
545 | (defgeneric effective-method-function-name (method) | |
546 | (:documentation | |
547 | "Returns the function name of an effective method.")) | |
548 | ||
549 | (defgeneric method-entry-function-name (method chain-head) | |
550 | (:documentation | |
551 | "Returns the function name of a method entry. | |
552 | ||
553 | The method entry is given as an effective method/chain-head pair, rather | |
554 | than as a method entry object because we want the function name before | |
555 | we've made the entry object.")) | |
556 | ||
557 | (defmethod effective-method-function-name ((method effective-method)) | |
558 | (let* ((class (effective-method-class method)) | |
559 | (message (effective-method-message method)) | |
560 | (message-class (sod-message-class message))) | |
561 | (format nil "~A__emethod_~A__~A" | |
562 | class | |
563 | (sod-class-nickname message-class) | |
564 | (sod-message-name message)))) | |
565 | ||
566 | (defmethod method-entry-function-name | |
567 | ((method effective-method) (chain-head sod-class)) | |
568 | (let* ((class (effective-method-class method)) | |
569 | (message (effective-method-message method)) | |
570 | (message-class (sod-message-class message))) | |
571 | (format nil "~A__mentry_~A__~A__~A" | |
572 | class | |
573 | (sod-class-nickname message-class) | |
574 | (sod-message-name message) | |
575 | (sod-class-nickname chain-head)))) | |
576 | ||
577 | (defmethod compute-method-entry-functions ((method basic-effective-method)) | |
578 | ||
579 | ;; OK, there's quite a lot of this, so hold tight. | |
580 | ;; | |
581 | ;; The first thing we need to do is find all of the related objects. This | |
582 | ;; is a bit verbose but fairly straightforward. | |
583 | ;; | |
584 | ;; Next, we generate the effective method body -- using COMPUTE-EFFECTIVE- | |
585 | ;; METHOD-BODY of all things. This gives us the declarations and body for | |
586 | ;; an effective method function, but we don't have an actual function yet. | |
587 | ;; | |
588 | ;; Now we look at the chains which are actually going to need a method | |
589 | ;; entry: only those chains whose tail (most specific) class is a | |
590 | ;; superclass of the class which defined the message need an entry. We | |
591 | ;; build a list of these tail classes. | |
592 | ;; | |
593 | ;; Having done this, we decide whether it's better to generate a standalone | |
594 | ;; effective-method function and call it from each of the method entries, | |
595 | ;; or to inline the effective method body into each of the entries. | |
596 | ;; | |
597 | ;; Most of the complexity here comes from (a) dealing with the two | |
598 | ;; different strategies for constructing method entry functions and (b) | |
599 | ;; (unsurprisingly) the mess involved with dealing with varargs messages. | |
600 | ||
601 | (let* ((message (effective-method-message method)) | |
602 | (class (effective-method-class method)) | |
603 | (message-class (sod-message-class message)) | |
604 | (return-type (c-type-subtype (sod-message-type message))) | |
605 | (codegen (make-instance 'method-codegen | |
606 | :message message | |
607 | :class class | |
608 | :method method)) | |
609 | ||
610 | ;; Effective method function details. | |
611 | (emf-name (effective-method-function-name method)) | |
612 | (ilayout-type (c-type (* (struct (ilayout-struct-tag class))))) | |
613 | (emf-arg-tail (mapcar (lambda (arg) | |
614 | (if (eq (argument-name arg) *sod-ap*) | |
615 | (make-argument *sod-master-ap* | |
616 | (c-type va-list)) | |
617 | arg)) | |
618 | (sod-message-no-varargs-tail message))) | |
619 | (emf-type (c-type (fun (lisp return-type) | |
620 | ("sod__obj" (lisp ilayout-type)) | |
621 | . (sod-message-no-varargs-tail message)))) | |
622 | (result (if (eq return-type (c-type void)) nil | |
623 | (temporary-var codegen return-type))) | |
624 | (emf-target (or result :void)) | |
625 | ||
626 | ;; Method entry details. | |
627 | (chain-tails (remove-if-not (lambda (super) | |
628 | (sod-subclass-p super message-class)) | |
629 | (mapcar #'car | |
630 | (sod-class-chains class)))) | |
631 | (n-entries (length chain-tails)) | |
632 | (entry-args (sod-message-argument-tail message)) | |
633 | (parm-n (do ((prev "me" (car args)) | |
634 | (args entry-args (cdr args))) | |
635 | ((endp args) nil) | |
636 | (when (eq (car args) :ellipsis) | |
637 | (return prev)))) | |
638 | (entry-target (codegen-target codegen))) | |
639 | ||
640 | (labels ((setup-entry (tail) | |
641 | (let ((head (sod-class-chain-head tail))) | |
642 | (codegen-push codegen) | |
643 | (ensure-var codegen "sod__obj" ilayout-type | |
644 | (make-convert-to-ilayout-inst class | |
645 | head "me")))) | |
646 | (varargs-prologue () | |
647 | (ensure-var codegen *sod-master-ap* (c-type va-list)) | |
648 | (emit-inst codegen | |
649 | (make-va-start-inst *sod-master-ap* parm-n))) | |
650 | (varargs-epilogue () | |
651 | (emit-inst codegen (make-va-end-inst *sod-master-ap*))) | |
652 | (finish-entry (tail) | |
653 | (let* ((head (sod-class-chain-head tail)) | |
654 | (name (method-entry-function-name method head)) | |
655 | (type (c-type (fun (lisp return-type) | |
656 | ("me" (* (class tail))) | |
657 | . entry-args)))) | |
658 | (codegen-pop-function codegen name type)))) | |
659 | ||
660 | ;; Generate the method body. We'll work out what to do with it later. | |
661 | (codegen-push codegen) | |
662 | (compute-effective-method-body method codegen emf-target) | |
663 | (multiple-value-bind (vars insts) (codegen-pop codegen) | |
664 | (cond ((or (= n-entries 1) | |
665 | (<= (* n-entries (reduce #'+ insts :key #'inst-metric)) | |
666 | *method-entry-inline-threshold*)) | |
667 | ||
668 | ;; The effective method body is simple -- or there's only one | |
669 | ;; of them. We'll inline the method body into the entry | |
670 | ;; functions. | |
671 | (dolist (tail chain-tails) | |
672 | (setup-entry tail) | |
673 | (dolist (var vars) | |
674 | (ensure-var codegen (inst-name var) | |
675 | (inst-type var) (inst-init var))) | |
676 | (when parm-n (varargs-prologue)) | |
677 | (emit-insts codegen insts) | |
678 | (when parm-n (varargs-epilogue)) | |
679 | (deliver-expr codegen entry-target result) | |
680 | (finish-entry tail))) | |
681 | ||
682 | (t | |
683 | ||
684 | ;; The effective method body is complicated and we'd need more | |
685 | ;; than one copy. We'll generate an effective method function | |
686 | ;; and call it a lot. | |
687 | (codegen-build-function codegen emf-name emf-type vars | |
688 | (nconc insts (and result (list (make-return-inst result))))) | |
689 | ||
690 | (let ((call (make-call-inst emf-name | |
691 | (cons "sod__obj" (mapcar #'argument-name | |
692 | emf-arg-tail))))) | |
693 | (dolist (tail chain-tails) | |
694 | (setup-entry tail) | |
695 | (cond (parm-n | |
696 | (varargs-prologue) | |
697 | (convert-stmts codegen entry-target return-type | |
698 | (lambda (target) | |
699 | (deliver-expr codegen target call) | |
700 | (varargs-epilogue)))) | |
701 | (t | |
702 | (deliver-expr codegen entry-target call))) | |
703 | (finish-entry tail)))))) | |
704 | ||
705 | (codegen-functions codegen)))) | |
706 | ||
707 | (defmethod slot-unbound | |
708 | (class (method basic-effective-method) (slot-name (eql 'functions))) | |
709 | (setf (slot-value method 'functions) | |
710 | (compute-method-entry-functions method))) | |
711 | ||
ddee4bb1 MW |
712 | (defmethod method-entry-function-type ((entry method-entry)) |
713 | (let* ((method (method-entry-effective-method entry)) | |
714 | (message (effective-method-message method)) | |
715 | (type (sod-message-type message))) | |
716 | (c-type (fun (lisp (c-type-subtype type)) | |
717 | ("me" (* (class (method-entry-chain-tail entry)))) | |
718 | . (sod-message-argument-tail message))))) | |
719 | ||
720 | (defmethod make-method-entry ((method basic-effective-method) | |
721 | (chain-head sod-class) (chain-tail sod-class)) | |
722 | (make-instance 'method-entry | |
723 | :method method | |
724 | :chain-head chain-head | |
725 | :chain-tail chain-tail)) | |
1f1d88f5 MW |
726 | |
727 | ;;;----- That's all, folks -------------------------------------------------- |