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1 | ;;; -*-lisp-*- |
2 | ;;; | |
dea4d055 | 3 | ;;; Code generation protocol |
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4 | ;;; |
5 | ;;; (c) 2009 Straylight/Edgeware | |
6 | ;;; | |
7 | ||
8 | ;;;----- Licensing notice --------------------------------------------------- | |
9 | ;;; | |
dea4d055 | 10 | ;;; This file is part of the Sensble Object Design, an object system for C. |
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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." | |
44 | t)) | |
45 | (defgeneric (setf var-in-use-p) (value var) | |
46 | (:documentation | |
3109662a | 47 | "Record whether VAR is currently being used. See `with-temporary-var'.")) |
1f1d88f5 | 48 | |
dea4d055 | 49 | ;; Root class. |
1f1d88f5 | 50 | |
dea4d055 MW |
51 | (export 'temporary-name) |
52 | (defclass temporary-name () | |
53 | ((tag :initarg :tag :reader temp-tag)) | |
54 | (:documentation | |
55 | "Base class for temporary variable and argument names.")) | |
1f1d88f5 | 56 | |
dea4d055 | 57 | ;; Important variables. |
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58 | |
59 | (defparameter *temporary-index* 0 | |
60 | "Index for temporary name generation. | |
61 | ||
62 | This is automatically reset to zero before the output functions are | |
63 | invoked to write a file. This way, we can ensure that the same output | |
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64 | file is always produced from the same input." |
65 | ;; FIXME: this is currently a lie. Need some protocol to ensure that this | |
66 | ;; happens. | |
67 | ) | |
1f1d88f5 | 68 | |
dea4d055 | 69 | ;; Important temporary names. |
1f1d88f5 | 70 | |
dea4d055 | 71 | (export '(*sod-ap* *sod-master-ap*)) |
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72 | (defparameter *sod-ap* |
73 | (make-instance 'temporary-name :tag "sod__ap")) | |
74 | (defparameter *sod-master-ap* | |
75 | (make-instance 'temporary-name :tag "sod__master_ap")) | |
76 | ||
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 | |
88 | generator. Both statements and expressions map can be represented by | |
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89 | trees of instructions. The `definst' macro is a convenient way of |
90 | defining new instructions. | |
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91 | |
92 | The only important protocol for instructions is output, which is achieved | |
3109662a | 93 | by calling `print-object' with `*print-escape*' nil. |
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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) |
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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. | |
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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.") | |
110 | (:method (inst) 1)) | |
111 | ||
dea4d055 MW |
112 | ;; Instruction definition. |
113 | ||
114 | (export 'definst) | |
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115 | (defmacro definst (code (streamvar) args &body body) |
116 | "Define an instruction type and describe how to output it. | |
117 | ||
3109662a MW |
118 | An `inst' can represent any structured piece of output syntax: a |
119 | statement, expression or declaration, for example. This macro defines the | |
120 | following things: | |
1f1d88f5 | 121 | |
3109662a | 122 | * A class `CODE-inst' to represent the instruction. |
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123 | |
124 | * Instance slots named after the ARGS, with matching keyword initargs, | |
3109662a | 125 | and `inst-ARG' readers. |
1f1d88f5 | 126 | |
3109662a | 127 | * A constructor `make-CODE-inst' which accepts the ARGS (in order, not |
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128 | with keywords) as arguments and returns a fresh instance. |
129 | ||
3109662a | 130 | * A print method, which prints a diagnostic dump if `*print-escape*' is |
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131 | set, or invokes the BODY (with STREAMVAR bound to the output stream) |
132 | otherwise. The BODY is expected to produce target code at this | |
133 | point." | |
134 | ||
135 | (let ((inst-var (gensym "INST")) | |
136 | (class-name (symbolicate code '-inst)) | |
137 | (keys (mapcar (lambda (arg) (intern (symbol-name arg) :keyword)) | |
138 | args))) | |
139 | `(progn | |
140 | (defclass ,class-name (inst) | |
141 | ,(mapcar (lambda (arg key) | |
142 | `(,arg :initarg ,key :reader ,(symbolicate 'inst- arg))) | |
143 | args keys)) | |
144 | (defun ,(symbolicate 'make- code '-inst) (,@args) | |
145 | (make-instance ',class-name ,@(mappend #'list keys args))) | |
146 | (defmethod inst-metric ((,inst-var ,class-name)) | |
147 | (with-slots (,@args) ,inst-var | |
148 | (+ 1 ,@(mapcar (lambda (arg) `(inst-metric ,arg)) args)))) | |
149 | (defmethod print-object ((,inst-var ,class-name) ,streamvar) | |
150 | (with-slots (,@args) ,inst-var | |
151 | (if *print-escape* | |
152 | (print-unreadable-object (,inst-var ,streamvar :type t) | |
153 | (format stream "~@<~@{~S ~@_~S~^ ~_~}~:>" | |
154 | ,@(mappend #'list keys args))) | |
155 | (progn ,@body))))))) | |
156 | ||
dea4d055 MW |
157 | ;; Important instruction classes. |
158 | ||
159 | (export '(block-inst make-block-inst var-inst make-var-inst | |
160 | function-inst make-function-inst set-inst make-set-inst | |
161 | return-inst make-return-inst expr-inst make-expr-inst | |
162 | inst-decls inst-body inst-name inst-type inst-init inst-var | |
163 | inst-expr)) | |
164 | ||
165 | (definst var (stream) (name type init) | |
166 | (pprint-c-type type stream name) | |
167 | (when init | |
168 | (format stream " = ~A" init))) | |
169 | (definst set (stream) (var expr) | |
170 | (format stream "~@<~A = ~@_~2I~A;~:>" var expr)) | |
171 | (definst return (stream) (expr) | |
172 | (format stream "return~@[ (~A)~];" expr)) | |
173 | (definst expr (stream) (expr) | |
174 | (format stream "~A;" expr)) | |
175 | (definst block (stream) (decls body) | |
176 | (format stream "{~:@_~@< ~2I~@[~{~A;~:@_~}~:@_~]~{~A~^~:@_~}~:>~:@_}" | |
177 | decls body)) | |
178 | (definst function (stream) (name type body) | |
179 | (pprint-logical-block (stream nil) | |
180 | (princ "static " stream) | |
181 | (pprint-c-type type stream name) | |
182 | (format stream "~:@_~A~:@_~:@_" body))) | |
183 | ||
184 | ;; Formatting utilities. | |
185 | ||
1f1d88f5 | 186 | (defun format-compound-statement* (stream child morep thunk) |
3109662a | 187 | "Underlying function for `format-compound-statement'." |
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188 | (cond ((typep child 'block-inst) |
189 | (funcall thunk stream) | |
190 | (write-char #\space stream) | |
191 | (princ child stream) | |
192 | (when morep (write-char #\space stream))) | |
193 | (t | |
194 | (pprint-logical-block (stream nil) | |
195 | (funcall thunk stream) | |
196 | (write-char #\space stream) | |
197 | (pprint-indent :block 2 stream) | |
198 | (pprint-newline :linear stream) | |
199 | (princ child stream) | |
200 | (pprint-indent :block 0 stream) | |
201 | (case morep | |
202 | (:space | |
203 | (write-char #\space stream) | |
204 | (pprint-newline :linear stream)) | |
dea4d055 | 205 | ((t) |
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206 | (pprint-newline :mandatory stream))))))) |
207 | ||
dea4d055 | 208 | (export 'format-compound-statement) |
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209 | (defmacro format-compound-statement |
210 | ((stream child &optional morep) &body body) | |
211 | "Format a compound statement to STREAM. | |
212 | ||
213 | The introductory material is printed by BODY. The CHILD is formatted | |
3109662a | 214 | properly according to whether it's a `block-inst'. If MOREP is true, then |
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215 | allow for more stuff following the child." |
216 | `(format-compound-statement* ,stream ,child ,morep | |
217 | (lambda (,stream) ,@body))) | |
218 | ||
219 | ;;;-------------------------------------------------------------------------- | |
dea4d055 | 220 | ;;; Code generation. |
1f1d88f5 | 221 | |
dea4d055 | 222 | ;; Accessors. |
1f1d88f5 | 223 | |
dea4d055 MW |
224 | (export 'codegen-functions) |
225 | (defgeneric codegen-functions (codegen) | |
1f1d88f5 | 226 | (:documentation |
3109662a | 227 | "Return the list of `function-inst's of completed functions.")) |
1f1d88f5 | 228 | |
dea4d055 | 229 | (export 'ensure-var) |
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230 | (defgeneric ensure-var (codegen name type &optional init) |
231 | (:documentation | |
232 | "Add a variable to CODEGEN's list. | |
233 | ||
3109662a | 234 | The variable is called NAME (which should be comparable using `equal' and |
1f1d88f5 | 235 | print to an identifier) and has the given TYPE. If INIT is present and |
3109662a | 236 | non-nil it is an expression `inst' used to provide the variable with an |
dea4d055 | 237 | initial value.")) |
1f1d88f5 | 238 | |
dea4d055 MW |
239 | (export '(emit-inst emit-insts)) |
240 | (defgeneric emit-inst (codegen inst) | |
241 | (:documentation | |
242 | "Add INST to the end of CODEGEN's list of instructions.")) | |
243 | (defgeneric emit-insts (codegen insts) | |
244 | (:documentation | |
245 | "Add a list of INSTS to the end of CODEGEN's list of instructions.") | |
246 | (:method (codegen insts) | |
247 | (dolist (inst insts) (emit-inst codegen inst)))) | |
1f1d88f5 | 248 | |
dea4d055 | 249 | (export 'codegen-push) |
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250 | (defgeneric codegen-push (codegen) |
251 | (:documentation | |
252 | "Pushes the current code generation state onto a stack. | |
253 | ||
dea4d055 | 254 | The state consists of the accumulated variables and instructions.")) |
1f1d88f5 | 255 | |
dea4d055 | 256 | (export 'codegen-pop) |
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257 | (defgeneric codegen-pop (codegen) |
258 | (:documentation | |
259 | "Pops a saved state off of the CODEGEN's stack. | |
260 | ||
261 | Returns the newly accumulated variables and instructions as lists, as | |
dea4d055 | 262 | separate values.")) |
1f1d88f5 | 263 | |
dea4d055 | 264 | (export 'codegen-add-function) |
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265 | (defgeneric codegen-add-function (codegen function) |
266 | (:documentation | |
267 | "Adds a function to CODEGEN's list. | |
268 | ||
269 | Actually, we're not picky: FUNCTION can be any kind of object that you're | |
3109662a | 270 | willing to find in the list returned by `codegen-functions'.")) |
dea4d055 MW |
271 | |
272 | (export 'temporary-var) | |
273 | (defgeneric temporary-var (codegen type) | |
274 | (:documentation | |
275 | "Return the name of a temporary variable. | |
276 | ||
277 | The temporary variable will have the given TYPE, and will be marked | |
278 | in-use. You should clear the in-use flag explicitly when you've finished | |
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279 | with the variable -- or, better, use `with-temporary-var' to do the |
280 | cleanup automatically.")) | |
1f1d88f5 | 281 | |
dea4d055 | 282 | (export 'codegen-build-function) |
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283 | (defun codegen-build-function (codegen name type vars insts) |
284 | "Build a function and add it to CODEGEN's list. | |
285 | ||
286 | Returns the function's name." | |
287 | (codegen-add-function codegen | |
288 | (make-function-inst name type | |
289 | (make-block-inst vars insts))) | |
290 | name) | |
291 | ||
dea4d055 MW |
292 | (export 'codegen-pop-block) |
293 | (defgeneric codegen-pop-block (codegen) | |
294 | (:documentation | |
3109662a | 295 | "Makes a block (`block-inst') out of the completed code in CODEGEN.") |
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296 | (:method (codegen) |
297 | (multiple-value-bind (vars insts) (codegen-pop codegen) | |
298 | (make-block-inst vars insts)))) | |
299 | ||
300 | (export 'codegen-pop-function) | |
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301 | (defgeneric codegen-pop-function (codegen name type) |
302 | (:documentation | |
303 | "Makes a function out of the completed code in CODEGEN. | |
304 | ||
305 | The NAME can be any object you like. The TYPE should be a function type | |
306 | object which includes argument names. The return value is the NAME.") | |
dea4d055 | 307 | (:method (codegen name type) |
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308 | (multiple-value-bind (vars insts) (codegen-pop codegen) |
309 | (codegen-build-function codegen name type vars insts)))) | |
310 | ||
dea4d055 | 311 | (export 'with-temporary-var) |
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312 | (defmacro with-temporary-var ((codegen var type) &body body) |
313 | "Evaluate BODY with VAR bound to a temporary variable name. | |
314 | ||
315 | During BODY, VAR will be marked in-use; when BODY ends, VAR will be marked | |
316 | available for re-use." | |
317 | `(let ((,var (temporary-var ,codegen ,type))) | |
318 | (unwind-protect | |
319 | (progn ,@body) | |
320 | (setf (var-in-use-p ,var) nil)))) | |
321 | ||
322 | ;;;-------------------------------------------------------------------------- | |
323 | ;;; Code generation idioms. | |
324 | ||
dea4d055 | 325 | (export 'deliver-expr) |
1f1d88f5 MW |
326 | (defun deliver-expr (codegen target expr) |
327 | "Emit code to deliver the value of EXPR to the TARGET. | |
328 | ||
329 | The TARGET may be one of the following. | |
330 | ||
3109662a | 331 | * `:void', indicating that the value is to be discarded. The expression |
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332 | will still be evaluated. |
333 | ||
3109662a MW |
334 | * `:void-return', indicating that the value is to be discarded (as for |
335 | `:void') and furthermore a `return' from the current function should | |
336 | be forced after computing the value. | |
1f1d88f5 | 337 | |
3109662a MW |
338 | * `:return', indicating that the value is to be returned from the |
339 | current function. | |
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340 | |
341 | * A variable name, indicating that the value is to be stored in the | |
342 | variable. | |
343 | ||
3109662a MW |
344 | In the cases of `:return', `:void' and `:void-return' targets, it is valid |
345 | for EXPR to be nil; this signifies that no computation needs to be | |
346 | performed. Variable-name targets require an expression." | |
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347 | |
348 | (case target | |
349 | (:return (emit-inst codegen (make-return-inst expr))) | |
350 | (:void (when expr (emit-inst codegen (make-expr-inst expr)))) | |
351 | (:void-return (when expr (emit-inst codegen (make-expr-inst expr))) | |
352 | (emit-inst codegen (make-return-inst nil))) | |
353 | (t (emit-inst codegen (make-set-inst target expr))))) | |
354 | ||
dea4d055 | 355 | (export 'convert-stmts) |
1f1d88f5 | 356 | (defun convert-stmts (codegen target type func) |
3109662a | 357 | "Invoke FUNC to deliver a value to a non-`:return' target. |
1f1d88f5 | 358 | |
3109662a MW |
359 | FUNC is a function which accepts a single argument, a non-`:return' |
360 | target, and generates statements which deliver a value (see | |
361 | `deliver-expr') of the specified TYPE to this target. In general, the | |
362 | generated code will have the form | |
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363 | |
364 | setup instructions... | |
3109662a | 365 | (deliver-expr CODEGEN TARGET (compute value...)) |
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366 | cleanup instructions... |
367 | ||
368 | where the cleanup instructions are essential to the proper working of the | |
369 | generated program. | |
370 | ||
3109662a MW |
371 | The `convert-stmts' function will call FUNC to generate code, and arrange |
372 | that its value is correctly delivered to TARGET, regardless of what the | |
373 | TARGET is -- i.e., it lifts the restriction to non-`:return' targets. It | |
374 | does this by inventing a new temporary variable." | |
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375 | |
376 | (case target | |
377 | (:return (with-temporary-var (codegen var type) | |
378 | (funcall func var) | |
379 | (deliver-expr codegen target var))) | |
380 | (:void-return (funcall func :void) | |
381 | (emit-inst codegen (make-return-inst nil))) | |
382 | (t (funcall func target)))) | |
383 | ||
384 | ;;;----- That's all, folks -------------------------------------------------- |