1 ;;;; structures for the first intermediate representation in the
4 ;;;; This software is part of the SBCL system. See the README file for
7 ;;;; This software is derived from the CMU CL system, which was
8 ;;;; written at Carnegie Mellon University and released into the
9 ;;;; public domain. The software is in the public domain and is
10 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
11 ;;;; files for more information.
15 ;;; The front-end data structure (IR1) is composed of nodes and
16 ;;; continuations. The general idea is that continuations contain
17 ;;; top-down information and nodes contain bottom-up, derived
18 ;;; information. A continuation represents a place in the code, while
19 ;;; a node represents code that does something.
21 ;;; This representation is more of a flow-graph than an augmented
22 ;;; syntax tree. The evaluation order is explicitly represented in the
23 ;;; linkage by continuations, rather than being implicit in the nodes
24 ;;; which receive the the results of evaluation. This allows us to
25 ;;; decouple the flow of results from the flow of control. A
26 ;;; continuation represents both, but the continuation can represent
27 ;;; the case of a discarded result by having no DEST.
29 (def!struct (continuation
30 (:make-load-form-fun ignore-it)
31 (:constructor make-continuation (&optional dest)))
32 ;; an indication of the way that this continuation is currently used
35 ;; A continuation for which all control-related slots have the
36 ;; default values. A continuation is unused during IR1 conversion
37 ;; until it is assigned a block, and may be also be temporarily
38 ;; unused during later manipulations of IR1. In a consistent
39 ;; state there should never be any mention of :UNUSED
40 ;; continuations. Next can have a non-null value if the next node
41 ;; has already been determined.
44 ;; A continuation that has been deleted from IR1. Any pointers into
45 ;; IR1 are cleared. There are two conditions under which a deleted
46 ;; continuation may appear in code:
47 ;; -- The CONT of the LAST node in a block may be a deleted
48 ;; continuation when the original receiver of the continuation's
49 ;; value was deleted. Note that DEST in a deleted continuation is
50 ;; null, so it is easy to know not to attempt delivering any
51 ;; values to the continuation.
52 ;; -- Unreachable code that hasn't been deleted yet may receive
53 ;; deleted continuations. All such code will be in blocks that
54 ;; have DELETE-P set. All unreachable code is deleted by control
55 ;; optimization, so the backend doesn't have to worry about this.
58 ;; The continuation that is the START of BLOCK. This is the only kind
59 ;; of continuation that can have more than one use. The BLOCK's
60 ;; START-USES is a list of all the uses.
62 ;; :DELETED-BLOCK-START
63 ;; Like :BLOCK-START, but BLOCK has been deleted. A block
64 ;; starting continuation is made into a deleted block start when
65 ;; the block is deleted, but the continuation still may have
66 ;; value semantics. Since there isn't any code left, next is
70 ;; A continuation that is the CONT of some node in BLOCK.
71 (kind :unused :type (member :unused :deleted :inside-block :block-start
72 :deleted-block-start))
73 ;; The node which receives this value, if any. In a deleted
74 ;; continuation, this is null even though the node that receives
75 ;; this continuation may not yet be deleted.
76 (dest nil :type (or node null))
77 ;; If this is a NODE, then it is the node which is to be evaluated
78 ;; next. This is always null in :DELETED and :UNUSED continuations,
79 ;; and will be null in a :INSIDE-BLOCK continuation when this is the
81 (next nil :type (or node null))
82 ;; an assertion on the type of this continuation's value
83 (asserted-type *wild-type* :type ctype)
84 ;; cached type of this continuation's value. If NIL, then this must
85 ;; be recomputed: see CONTINUATION-DERIVED-TYPE.
86 (%derived-type nil :type (or ctype null))
87 ;; the node where this continuation is used, if unique. This is always
88 ;; null in :DELETED and :UNUSED continuations, and is never null in
89 ;; :INSIDE-BLOCK continuations. In a :BLOCK-START continuation, the
90 ;; Block's START-USES indicate whether NIL means no uses or more
92 (use nil :type (or node null))
93 ;; the basic block this continuation is in. This is null only in
94 ;; :DELETED and :UNUSED continuations. Note that blocks that are
95 ;; unreachable but still in the DFO may receive deleted
96 ;; continuations, so it isn't o.k. to assume that any continuation
97 ;; that you pick up out of its DEST node has a BLOCK.
98 (block nil :type (or cblock null))
99 ;; set to true when something about this continuation's value has
100 ;; changed. See REOPTIMIZE-CONTINUATION. This provides a way for IR1
101 ;; optimize to determine which operands to a node have changed. If
102 ;; the optimizer for this node type doesn't care, it can elect not
103 ;; to clear this flag.
104 (reoptimize t :type boolean)
105 ;; an indication of what we have proven about how this contination's
106 ;; type assertion is satisfied:
109 ;; No type check is necessary (proven type is a subtype of the assertion.)
112 ;; A type check is needed.
115 ;; Don't do a type check, but believe (intersect) the assertion.
116 ;; A T check can be changed to :DELETED if we somehow prove the
117 ;; check is unnecessary, or if we eliminate it through a policy
121 ;; Type check generation sets the slot to this if a check is
122 ;; called for, but it believes it has proven that the check won't
123 ;; be done for policy reasons or because a safe implementation
124 ;; will be used. In the latter case, LTN must ensure that a safe
125 ;; implementation *is* used.
128 ;; There is a compile-time type error in some use of this
129 ;; continuation. A type check should still be generated, but be
132 ;; This is computed lazily by CONTINUATION-DERIVED-TYPE, so use
133 ;; CONTINUATION-TYPE-CHECK instead of the %'ed slot accessor.
134 (%type-check t :type (member t nil :deleted :no-check :error))
135 ;; something or other that the back end annotates this continuation with
137 ;; uses of this continuation in the lexical environment. They are
138 ;; recorded so that when one continuation is substituted for another
139 ;; the environment may be updated properly.
140 (lexenv-uses nil :type list))
142 (def!method print-object ((x continuation) stream)
143 (print-unreadable-object (x stream :type t :identity t)))
145 (defstruct (node (:constructor nil)
147 ;; the bottom-up derived type for this node. This does not take into
148 ;; consideration output type assertions on this node (actually on its CONT).
149 (derived-type *wild-type* :type ctype)
150 ;; True if this node needs to be optimized. This is set to true
151 ;; whenever something changes about the value of a continuation
152 ;; whose DEST is this node.
153 (reoptimize t :type boolean)
154 ;; the continuation which receives the value of this node. This also
155 ;; indicates what we do controlwise after evaluating this node. This
156 ;; may be null during IR1 conversion.
157 (cont nil :type (or continuation null))
158 ;; the continuation that this node is the next of. This is null
159 ;; during IR1 conversion when we haven't linked the node in yet or
160 ;; in nodes that have been deleted from the IR1 by UNLINK-NODE.
161 (prev nil :type (or continuation null))
162 ;; the lexical environment this node was converted in
163 (lexenv *lexenv* :type lexenv)
164 ;; a representation of the source code responsible for generating
167 ;; For a form introduced by compilation (does not appear in the
168 ;; original source), the path begins with a list of all the
169 ;; enclosing introduced forms. This list is from the inside out,
170 ;; with the form immediately responsible for this node at the head
173 ;; Following the introduced forms is a representation of the
174 ;; location of the enclosing original source form. This transition
175 ;; is indicated by the magic ORIGINAL-SOURCE-START marker. The first
176 ;; element of the original source is the "form number", which is the
177 ;; ordinal number of this form in a depth-first, left-to-right walk
178 ;; of the truly-top-level form in which this appears.
180 ;; Following is a list of integers describing the path taken through
181 ;; the source to get to this point:
182 ;; (K L M ...) => (NTH K (NTH L (NTH M ...)))
184 ;; The last element in the list is the top level form number, which
185 ;; is the ordinal number (in this call to the compiler) of the truly
186 ;; top level form containing the original source.
187 (source-path *current-path* :type list)
188 ;; If this node is in a tail-recursive position, then this is set to
189 ;; T. At the end of IR1 (in physical environment analysis) this is
190 ;; computed for all nodes (after cleanup code has been emitted).
191 ;; Before then, a non-null value indicates that IR1 optimization has
192 ;; converted a tail local call to a direct transfer.
194 ;; If the back-end breaks tail-recursion for some reason, then it
195 ;; can null out this slot.
196 (tail-p nil :type boolean))
198 ;;; Flags that are used to indicate various things about a block, such
199 ;;; as what optimizations need to be done on it:
200 ;;; -- REOPTIMIZE is set when something interesting happens the uses of a
201 ;;; continuation whose Dest is in this block. This indicates that the
202 ;;; value-driven (forward) IR1 optimizations should be done on this block.
203 ;;; -- FLUSH-P is set when code in this block becomes potentially flushable,
204 ;;; usually due to a continuation's DEST becoming null.
205 ;;; -- TYPE-CHECK is true when the type check phase should be run on this
206 ;;; block. IR1 optimize can introduce new blocks after type check has
207 ;;; already run. We need to check these blocks, but there is no point in
208 ;;; checking blocks we have already checked.
209 ;;; -- DELETE-P is true when this block is used to indicate that this block
210 ;;; has been determined to be unreachable and should be deleted. IR1
211 ;;; phases should not attempt to examine or modify blocks with DELETE-P
212 ;;; set, since they may:
213 ;;; - be in the process of being deleted, or
214 ;;; - have no successors, or
215 ;;; - receive :DELETED continuations.
216 ;;; -- TYPE-ASSERTED, TEST-MODIFIED
217 ;;; These flags are used to indicate that something in this block
218 ;;; might be of interest to constraint propagation. TYPE-ASSERTED
219 ;;; is set when a continuation type assertion is strengthened.
220 ;;; TEST-MODIFIED is set whenever the test for the ending IF has
221 ;;; changed (may be true when there is no IF.)
222 (def-boolean-attribute block
223 reoptimize flush-p type-check delete-p type-asserted test-modified)
225 (macrolet ((frob (slot)
226 `(defmacro ,(symbolicate "BLOCK-" slot) (block)
227 `(block-attributep (block-flags ,block) ,',slot))))
233 (frob test-modified))
235 ;;; The CBLOCK structure represents a basic block. We include
236 ;;; SSET-ELEMENT so that we can have sets of blocks. Initially the
237 ;;; SSET-ELEMENT-NUMBER is null, DFO analysis numbers in reverse DFO.
238 ;;; During IR2 conversion, IR1 blocks are re-numbered in forward emit
239 ;;; order. This latter numbering also forms the basis of the block
240 ;;; numbering in the debug-info (though that is relative to the start
241 ;;; of the function.)
242 (defstruct (cblock (:include sset-element)
243 (:constructor make-block (start))
244 (:constructor make-block-key)
247 (:copier copy-block))
248 ;; a list of all the blocks that are predecessors/successors of this
249 ;; block. In well-formed IR1, most blocks will have one successor.
250 ;; The only exceptions are:
251 ;; 1. component head blocks (any number)
252 ;; 2. blocks ending in an IF (1 or 2)
253 ;; 3. blocks with DELETE-P set (zero)
254 (pred nil :type list)
255 (succ nil :type list)
256 ;; the continuation which heads this block (either a :BLOCK-START or
257 ;; :DELETED-BLOCK-START), or NIL when we haven't made the start
258 ;; continuation yet (and in the dummy component head and tail
260 (start nil :type (or continuation null))
261 ;; a list of all the nodes that have START as their CONT
262 (start-uses nil :type list)
263 ;; the last node in this block. This is NIL when we are in the
264 ;; process of building a block (and in the dummy component head and
266 (last nil :type (or node null))
267 ;; the forward and backward links in the depth-first ordering of the
268 ;; blocks. These slots are NIL at beginning/end.
269 (next nil :type (or null cblock))
270 (prev nil :type (or null cblock))
271 ;; This block's attributes: see above.
272 (flags (block-attributes reoptimize flush-p type-check type-asserted
275 ;; CMU CL had a KILL slot here, documented as "set used by
276 ;; constraint propagation", which was used in constraint propagation
277 ;; as a list of LAMBDA-VARs killed, and in copy propagation as an
278 ;; SSET, representing I dunno what. I (WHN) found this confusing,
279 ;; and furthermore it caused type errors when I was trying to make
280 ;; the compiler produce fully general LAMBDA functions directly
281 ;; (instead of doing as CMU CL always did, producing extra little
282 ;; functions which return the LAMDBA you need) and therefore taking
283 ;; a new path through the compiler. So I split this into two:
284 ;; KILL-LIST = list of LAMBDA-VARs killed, used in constraint propagation
285 ;; KILL-SSET = an SSET value, used in copy propagation
286 (kill-list nil :type list)
287 (kill-sset nil :type (or sset null))
288 ;; other sets used in constraint propagation and/or copy propagation
292 ;; the component this block is in, or NIL temporarily during IR1
293 ;; conversion and in deleted blocks
295 (aver-live-component *current-component*)
297 :type (or component null))
298 ;; a flag used by various graph-walking code to determine whether
299 ;; this block has been processed already or what. We make this
300 ;; initially NIL so that FIND-INITIAL-DFO doesn't have to scan the
301 ;; entire initial component just to clear the flags.
303 ;; some kind of info used by the back end
305 ;; If true, then constraints that hold in this block and its
306 ;; successors by merit of being tested by its IF predecessor.
307 (test-constraint nil :type (or sset null)))
308 (def!method print-object ((cblock cblock) stream)
309 (print-unreadable-object (cblock stream :type t :identity t)
310 (format stream ":START c~W" (cont-num (block-start cblock)))))
312 ;;; The BLOCK-ANNOTATION class is inherited (via :INCLUDE) by
313 ;;; different BLOCK-INFO annotation structures so that code
314 ;;; (specifically control analysis) can be shared.
315 (defstruct (block-annotation (:constructor nil)
317 ;; The IR1 block that this block is in the INFO for.
318 (block (missing-arg) :type cblock)
319 ;; the next and previous block in emission order (not DFO). This
320 ;; determines which block we drop though to, and is also used to
321 ;; chain together overflow blocks that result from splitting of IR2
322 ;; blocks in lifetime analysis.
323 (next nil :type (or block-annotation null))
324 (prev nil :type (or block-annotation null)))
326 ;;; A COMPONENT structure provides a handle on a connected piece of
327 ;;; the flow graph. Most of the passes in the compiler operate on
328 ;;; COMPONENTs rather than on the entire flow graph.
330 ;;; According to the CMU CL internals/front.tex, the reason for
331 ;;; separating compilation into COMPONENTs is
332 ;;; to increase the efficiency of large block compilations. In
333 ;;; addition to improving locality of reference and reducing the
334 ;;; size of flow analysis problems, this allows back-end data
335 ;;; structures to be reclaimed after the compilation of each
337 (defstruct (component (:copier nil))
338 ;; the kind of component
340 ;; (The terminology here is left over from before
341 ;; sbcl-0.pre7.34.flaky5.2, when there was no such thing as
342 ;; FUNCTIONAL-HAS-EXTERNAL-REFERENCES-P, so that Python was
343 ;; incapable of building standalone :EXTERNAL functions, but instead
344 ;; had to implement things like #'CL:COMPILE as FUNCALL of a little
345 ;; toplevel stub whose sole purpose was to return an :EXTERNAL
348 ;; The possibilities are:
350 ;; an ordinary component, containing non-top-level code
352 ;; a component containing only load-time code
354 ;; In the old system, before FUNCTIONAL-HAS-EXTERNAL-REFERENCES-P
355 ;; was defined, this was necessarily a component containing both
356 ;; top level and run-time code. Now this state is also used for
357 ;; a component with HAS-EXTERNAL-REFERENCES-P functionals in it.
359 ;; the result of initial IR1 conversion, on which component
360 ;; analysis has not been done
362 ;; debris left over from component analysis
364 ;; See also COMPONENT-TOPLEVELISH-P.
365 (kind nil :type (member nil :toplevel :complex-toplevel :initial :deleted))
366 ;; the blocks that are the dummy head and tail of the DFO
368 ;; Entry/exit points have these blocks as their
369 ;; predecessors/successors. Null temporarily. The start and return
370 ;; from each non-deleted function is linked to the component head
371 ;; and tail. Until physical environment analysis links NLX entry
372 ;; stubs to the component head, every successor of the head is a
373 ;; function start (i.e. begins with a BIND node.)
374 (head nil :type (or null cblock))
375 (tail nil :type (or null cblock))
376 ;; This becomes a list of the CLAMBDA structures for all functions
377 ;; in this component. OPTIONAL-DISPATCHes are represented only by
378 ;; their XEP and other associated lambdas. This doesn't contain any
379 ;; deleted or LET lambdas.
381 ;; Note that logical associations between CLAMBDAs and COMPONENTs
382 ;; seem to exist for a while before this is initialized. See e.g.
383 ;; the NEW-FUNS slot. In particular, I got burned by writing some
384 ;; code to use this value to decide which components need
385 ;; LOCALL-ANALYZE-COMPONENT, when it turns out that
386 ;; LOCALL-ANALYZE-COMPONENT had a role in initializing this value
387 ;; (and DFO stuff does too, maybe). Also, even after it's
388 ;; initialized, it might change as CLAMBDAs are deleted or merged.
390 (lambdas () :type list)
391 ;; a list of FUNCTIONALs for functions that are newly converted, and
392 ;; haven't been local-call analyzed yet. Initially functions are not
393 ;; in the LAMBDAS list. Local call analysis moves them there
394 ;; (possibly as LETs, or implicitly as XEPs if an OPTIONAL-DISPATCH.)
395 ;; Between runs of local call analysis there may be some debris of
396 ;; converted or even deleted functions in this list.
397 (new-funs () :type list)
398 ;; If this is true, then there is stuff in this component that could
399 ;; benefit from further IR1 optimization.
400 (reoptimize t :type boolean)
401 ;; If this is true, then the control flow in this component was
402 ;; messed up by IR1 optimizations, so the DFO should be recomputed.
403 (reanalyze nil :type boolean)
404 ;; some sort of name for the code in this component
405 (name "<unknown>" :type simple-string)
406 ;; When I am a child, this is :NO-IR2-YET.
407 ;; In my adulthood, IR2 stores notes to itself here.
408 ;; After I have left the great wheel and am staring into the GC, this
409 ;; is set to :DEAD to indicate that it's a gruesome error to operate
410 ;; on me (e.g. by using me as *CURRENT-COMPONENT*, or by pushing
411 ;; LAMBDAs onto my NEW-FUNS, as in sbcl-0.pre7.115).
412 (info :no-ir2-yet :type (or ir2-component (member :no-ir2-yet :dead)))
413 ;; the SOURCE-INFO structure describing where this component was
415 (source-info *source-info* :type source-info)
416 ;; count of the number of inline expansions we have done while
417 ;; compiling this component, to detect infinite or exponential
419 (inline-expansions 0 :type index)
420 ;; a map from combination nodes to things describing how an
421 ;; optimization of the node failed. The description is an alist
422 ;; (TRANSFORM . ARGS), where TRANSFORM is the structure describing
423 ;; the transform that failed, and ARGS is either a list of format
424 ;; arguments for the note, or the FUN-TYPE that would have
425 ;; enabled the transformation but failed to match.
426 (failed-optimizations (make-hash-table :test 'eq) :type hash-table)
427 ;; This is similar to NEW-FUNS, but is used when a function has
428 ;; already been analyzed, but new references have been added by
429 ;; inline expansion. Unlike NEW-FUNS, this is not disjoint from
430 ;; COMPONENT-LAMBDAS.
431 (reanalyze-funs nil :type list))
432 (defprinter (component :identity t)
434 (reanalyze :test reanalyze))
436 ;;; Check that COMPONENT is suitable for roles which involve adding
437 ;;; new code. (gotta love imperative programming with lotso in-place
439 (defun aver-live-component (component)
440 ;; FIXME: As of sbcl-0.pre7.115, we're asserting that
441 ;; COMPILE-COMPONENT hasn't happened yet. Might it be even better
442 ;; (certainly stricter, possibly also correct...) to assert that
443 ;; IR1-FINALIZE hasn't happened yet?
444 (aver (not (eql (component-info component) :dead))))
446 ;;; Before sbcl-0.7.0, there were :TOPLEVEL things which were magical
447 ;;; in multiple ways. That's since been refactored into the orthogonal
448 ;;; properties "optimized for locall with no arguments" and "externally
449 ;;; visible/referenced (so don't delete it)". The code <0.7.0 did a lot
450 ;;; of tests a la (EQ KIND :TOP_LEVEL) in the "don't delete it?" sense;
451 ;;; this function is a sort of literal translation of those tests into
454 ;;; FIXME: After things settle down, bare :TOPLEVEL might go away, at
455 ;;; which time it might be possible to replace the COMPONENT-KIND
456 ;;; :TOPLEVEL mess with a flag COMPONENT-HAS-EXTERNAL-REFERENCES-P
457 ;;; along the lines of FUNCTIONAL-HAS-EXTERNAL-REFERENCES-P.
458 (defun lambda-toplevelish-p (clambda)
459 (or (eql (lambda-kind clambda) :toplevel)
460 (lambda-has-external-references-p clambda)))
461 (defun component-toplevelish-p (component)
462 (member (component-kind component)
463 '(:toplevel :complex-toplevel)))
465 ;;; A CLEANUP structure represents some dynamic binding action. Blocks
466 ;;; are annotated with the current CLEANUP so that dynamic bindings
467 ;;; can be removed when control is transferred out of the binding
468 ;;; environment. We arrange for changes in dynamic bindings to happen
469 ;;; at block boundaries, so that cleanup code may easily be inserted.
470 ;;; The "mess-up" action is explicitly represented by a funny function
471 ;;; call or ENTRY node.
473 ;;; We guarantee that CLEANUPs only need to be done at block boundaries
474 ;;; by requiring that the exit continuations initially head their
475 ;;; blocks, and then by not merging blocks when there is a cleanup
477 (defstruct (cleanup (:copier nil))
478 ;; the kind of thing that has to be cleaned up
480 :type (member :special-bind :catch :unwind-protect :block :tagbody))
481 ;; the node that messes things up. This is the last node in the
482 ;; non-messed-up environment. Null only temporarily. This could be
483 ;; deleted due to unreachability.
484 (mess-up nil :type (or node null))
485 ;; a list of all the NLX-INFO structures whose NLX-INFO-CLEANUP is
486 ;; this cleanup. This is filled in by physical environment analysis.
487 (nlx-info nil :type list))
488 (defprinter (cleanup :identity t)
491 (nlx-info :test nlx-info))
493 ;;; A PHYSENV represents the result of physical environment analysis.
495 ;;; As far as I can tell from reverse engineering, this IR1 structure
496 ;;; represents the physical environment (which is probably not the
497 ;;; standard Lispy term for this concept, but I dunno what is the
498 ;;; standard term): those things in the lexical environment which a
499 ;;; LAMBDA actually interacts with. Thus in
500 ;;; (DEFUN FROB-THINGS (THINGS)
501 ;;; (DOLIST (THING THINGS)
502 ;;; (BLOCK FROBBING-ONE-THING
503 ;;; (MAPCAR (LAMBDA (PATTERN)
504 ;;; (WHEN (FITS-P THING PATTERN)
505 ;;; (RETURN-FROM FROB-THINGS (LIST :FIT THING PATTERN))))
507 ;;; the variables THINGS, THING, and PATTERN and the block names
508 ;;; FROB-THINGS and FROBBING-ONE-THING are all in the inner LAMBDA's
509 ;;; lexical environment, but of those only THING, PATTERN, and
510 ;;; FROB-THINGS are in its physical environment. In IR1, we largely
511 ;;; just collect the names of these things; in IR2 an IR2-PHYSENV
512 ;;; structure is attached to INFO and used to keep track of
513 ;;; associations between these names and less-abstract things (like
514 ;;; TNs, or eventually stack slots and registers). -- WHN 2001-09-29
515 (defstruct (physenv (:copier nil))
516 ;; the function that allocates this physical environment
517 (lambda (missing-arg) :type clambda :read-only t)
518 #| ; seems not to be used as of sbcl-0.pre7.51
519 ;; a list of all the lambdas that allocate variables in this
520 ;; physical environment
521 (lambdas nil :type list)
523 ;; This ultimately converges to a list of all the LAMBDA-VARs and
524 ;; NLX-INFOs needed from enclosing environments by code in this
525 ;; physical environment. In the meantime, it may be
526 ;; * NIL at object creation time
527 ;; * a superset of the correct result, generated somewhat later
528 ;; * smaller and smaller sets converging to the correct result as
529 ;; we notice and delete unused elements in the superset
530 (closure nil :type list)
531 ;; a list of NLX-INFO structures describing all the non-local exits
532 ;; into this physical environment
533 (nlx-info nil :type list)
534 ;; some kind of info used by the back end
536 (defprinter (physenv :identity t)
538 (closure :test closure)
539 (nlx-info :test nlx-info))
541 ;;; An TAIL-SET structure is used to accumulate information about
542 ;;; tail-recursive local calls. The "tail set" is effectively the
543 ;;; transitive closure of the "is called tail-recursively by"
546 ;;; All functions in the same tail set share the same TAIL-SET
547 ;;; structure. Initially each function has its own TAIL-SET, but when
548 ;;; IR1-OPTIMIZE-RETURN notices a tail local call, it joins the tail
549 ;;; sets of the called function and the calling function.
551 ;;; The tail set is somewhat approximate, because it is too early to
552 ;;; be sure which calls will be tail-recursive. Any call that *might*
553 ;;; end up tail-recursive causes TAIL-SET merging.
554 (defstruct (tail-set)
555 ;; a list of all the LAMBDAs in this tail set
556 (funs nil :type list)
557 ;; our current best guess of the type returned by these functions.
558 ;; This is the union across all the functions of the return node's
559 ;; RESULT-TYPE, excluding local calls.
560 (type *wild-type* :type ctype)
561 ;; some info used by the back end
563 (defprinter (tail-set :identity t)
568 ;;; The NLX-Info structure is used to collect various information
569 ;;; about non-local exits. This is effectively an annotation on the
570 ;;; CONTINUATION, although it is accessed by searching in the
571 ;;; PHYSENV-NLX-INFO.
572 (def!struct (nlx-info (:make-load-form-fun ignore-it))
573 ;; the cleanup associated with this exit. In a catch or
574 ;; unwind-protect, this is the :CATCH or :UNWIND-PROTECT cleanup,
575 ;; and not the cleanup for the escape block. The CLEANUP-KIND of
576 ;; this thus provides a good indication of what kind of exit is
578 (cleanup (missing-arg) :type cleanup)
579 ;; the continuation exited to (the CONT of the EXIT nodes). If this
580 ;; exit is from an escape function (CATCH or UNWIND-PROTECT), then
581 ;; physical environment analysis deletes the escape function and
582 ;; instead has the %NLX-ENTRY use this continuation.
584 ;; This slot is primarily an indication of where this exit delivers
585 ;; its values to (if any), but it is also used as a sort of name to
586 ;; allow us to find the NLX-Info that corresponds to a given exit.
587 ;; For this purpose, the Entry must also be used to disambiguate,
588 ;; since exits to different places may deliver their result to the
589 ;; same continuation.
590 (continuation (missing-arg) :type continuation)
591 ;; the entry stub inserted by physical environment analysis. This is
592 ;; a block containing a call to the %NLX-Entry funny function that
593 ;; has the original exit destination as its successor. Null only
595 (target nil :type (or cblock null))
596 ;; some kind of info used by the back end
598 (defprinter (nlx-info :identity t)
605 ;;; Variables, constants and functions are all represented by LEAF
606 ;;; structures. A reference to a LEAF is indicated by a REF node. This
607 ;;; allows us to easily substitute one for the other without actually
608 ;;; hacking the flow graph.
609 (def!struct (leaf (:make-load-form-fun ignore-it)
611 ;; (For public access to this slot, use LEAF-SOURCE-NAME.)
613 ;; the name of LEAF as it appears in the source, e.g. 'FOO or '(SETF
614 ;; FOO) or 'N or '*Z*, or the special .ANONYMOUS. value if there's
615 ;; no name for this thing in the source (as can happen for
616 ;; FUNCTIONALs, e.g. for anonymous LAMBDAs or for functions for
617 ;; top-level forms; and can also happen for anonymous constants) or
618 ;; perhaps also if the match between the name and the thing is
619 ;; skewed enough (e.g. for macro functions or method functions) that
620 ;; we don't want to have that name affect compilation
622 ;; The value of this slot in can affect ordinary runtime behavior,
623 ;; e.g. of special variables and known functions, not just debugging.
625 ;; See also the LEAF-DEBUG-NAME function and the
626 ;; FUNCTIONAL-%DEBUG-NAME slot.
627 (%source-name (missing-arg)
628 :type (or symbol (and cons (satisfies legal-fun-name-p)))
630 ;; the type which values of this leaf must have
631 (type *universal-type* :type ctype)
632 ;; where the TYPE information came from:
633 ;; :DECLARED, from a declaration.
634 ;; :ASSUMED, from uses of the object.
635 ;; :DEFINED, from examination of the definition.
636 ;; FIXME: This should be a named type. (LEAF-WHERE-FROM? Or
637 ;; perhaps just WHERE-FROM, since it's not just used in LEAF,
638 ;; but also in various DEFINE-INFO-TYPEs in globaldb.lisp,
639 ;; and very likely elsewhere too.)
640 (where-from :assumed :type (member :declared :assumed :defined))
641 ;; list of the REF nodes for this leaf
643 ;; true if there was ever a REF or SET node for this leaf. This may
644 ;; be true when REFS and SETS are null, since code can be deleted.
645 (ever-used nil :type boolean)
646 ;; some kind of info used by the back end
649 ;;; LEAF name operations
651 ;;; KLUDGE: wants CLOS..
652 (defun leaf-has-source-name-p (leaf)
653 (not (eq (leaf-%source-name leaf)
655 (defun leaf-source-name (leaf)
656 (aver (leaf-has-source-name-p leaf))
657 (leaf-%source-name leaf))
658 (defun leaf-debug-name (leaf)
659 (if (functional-p leaf)
660 ;; FUNCTIONALs have additional %DEBUG-NAME behavior.
661 (functional-debug-name leaf)
662 ;; Other objects just use their source name.
664 ;; (As of sbcl-0.pre7.85, there are a few non-FUNCTIONAL
665 ;; anonymous objects, (anonymous constants..) and those would
666 ;; fail here if we ever tried to get debug names from them, but
667 ;; it looks as though it's never interesting to get debug names
668 ;; from them, so it's moot. -- WHN)
669 (leaf-source-name leaf)))
671 ;;; The CONSTANT structure is used to represent known constant values.
672 ;;; If NAME is not null, then it is the name of the named constant
673 ;;; which this leaf corresponds to, otherwise this is an anonymous
675 (def!struct (constant (:include leaf))
676 ;; the value of the constant
678 (defprinter (constant :identity t)
679 (%source-name :test %source-name)
682 ;;; The BASIC-VAR structure represents information common to all
683 ;;; variables which don't correspond to known local functions.
684 (def!struct (basic-var (:include leaf)
686 ;; Lists of the set nodes for this variable.
687 (sets () :type list))
689 ;;; The GLOBAL-VAR structure represents a value hung off of the symbol
690 ;;; NAME. We use a :CONSTANT VAR when we know that the thing is a
691 ;;; constant, but don't know what the value is at compile time.
692 (def!struct (global-var (:include basic-var))
693 ;; kind of variable described
695 :type (member :special :global-function :global)))
696 (defprinter (global-var :identity t)
698 (type :test (not (eq type *universal-type*)))
699 (where-from :test (not (eq where-from :assumed)))
702 ;;; The SLOT-ACCESSOR structure represents slot accessor functions. It
703 ;;; is a subtype of GLOBAL-VAR to make it look more like a normal
705 (def!struct (slot-accessor (:include global-var
706 (where-from :defined)
707 (kind :global-function)))
708 ;; The description of the structure that this is an accessor for.
709 (for (missing-arg) :type sb!xc:class)
710 ;; The slot description of the slot.
711 (slot (missing-arg)))
712 (defprinter (slot-accessor :identity t)
717 ;;; A DEFINED-FUN represents a function that is defined in the same
718 ;;; compilation block, or that has an inline expansion, or that has a
719 ;;; non-NIL INLINEP value. Whenever we change the INLINEP state (i.e.
720 ;;; an inline proclamation) we copy the structure so that former
721 ;;; INLINEP values are preserved.
722 (def!struct (defined-fun (:include global-var
723 (where-from :defined)
724 (kind :global-function)))
725 ;; The values of INLINEP and INLINE-EXPANSION initialized from the
726 ;; global environment.
727 (inlinep nil :type inlinep)
728 (inline-expansion nil :type (or cons null))
729 ;; the block-local definition of this function (either because it
730 ;; was semi-inline, or because it was defined in this block). If
731 ;; this function is not an entry point, then this may be deleted or
732 ;; LET-converted. Null if we haven't converted the expansion yet.
733 (functional nil :type (or functional null)))
734 (defprinter (defined-fun :identity t)
737 (functional :test functional))
741 ;;; We default the WHERE-FROM and TYPE slots to :DEFINED and FUNCTION.
742 ;;; We don't normally manipulate function types for defined functions,
743 ;;; but if someone wants to know, an approximation is there.
744 (def!struct (functional (:include leaf
745 (%source-name '.anonymous.)
746 (where-from :defined)
747 (type (specifier-type 'function))))
748 ;; (For public access to this slot, use LEAF-DEBUG-NAME.)
750 ;; the name of FUNCTIONAL for debugging purposes, or NIL if we
751 ;; should just let the SOURCE-NAME fall through
753 ;; Unlike the SOURCE-NAME slot, this slot's value should never
754 ;; affect ordinary code behavior, only debugging/diagnostic behavior.
756 ;; The value of this slot can be anything, except that it shouldn't
757 ;; be a legal function name, since otherwise debugging gets
758 ;; confusing. (If a legal function name is a good name for the
759 ;; function, it should be in %SOURCE-NAME, and then we shouldn't
760 ;; need a %DEBUG-NAME.) In SBCL as of 0.pre7.87, it's always a
761 ;; string unless it's NIL, since that's how CMU CL represented debug
762 ;; names. However, eventually I (WHN) think it we should start using
763 ;; list values instead, since they have much nicer print properties
764 ;; (abbreviation, skipping package prefixes when unneeded, and
765 ;; renaming package prefixes when we do things like renaming SB!EXT
768 ;; E.g. for the function which implements (DEFUN FOO ...), we could
772 ;; for the function which implements the top level form
773 ;; (IN-PACKAGE :FOO) we could have
775 ;; %DEBUG-NAME="top level form (IN-PACKAGE :FOO)"
776 ;; for the function which implements FOO in
777 ;; (DEFUN BAR (...) (FLET ((FOO (...) ...)) ...))
780 ;; %DEBUG-NAME="FLET FOO in BAR"
781 ;; and for the function which implements FOO in
782 ;; (DEFMACRO FOO (...) ...)
784 ;; %SOURCE-NAME=FOO (or maybe .ANONYMOUS.?)
785 ;; %DEBUG-NAME="DEFMACRO FOO"
787 :type (or null (not (satisfies legal-fun-name-p)))
789 ;; some information about how this function is used. These values
793 ;; an ordinary function, callable using local call
796 ;; a lambda that is used in only one local call, and has in
797 ;; effect been substituted directly inline. The return node is
798 ;; deleted, and the result is computed with the actual result
799 ;; continuation for the call.
802 ;; Similar to :LET, but the call is an MV-CALL.
805 ;; similar to a LET, but can have other than one call as long as
806 ;; there is at most one non-tail call.
809 ;; a lambda that is an entry-point for an optional-dispatch.
810 ;; Similar to NIL, but requires greater caution, since local call
811 ;; analysis may create new references to this function. Also, the
812 ;; function cannot be deleted even if it has *no* references. The
813 ;; OPTIONAL-DISPATCH is in the LAMDBA-OPTIONAL-DISPATCH.
816 ;; an external entry point lambda. The function it is an entry
817 ;; for is in the ENTRY-FUN slot.
820 ;; a top level lambda, holding a compiled top level form.
821 ;; Compiled very much like NIL, but provides an indication of
822 ;; top level context. A :TOPLEVEL lambda should have *no*
823 ;; references. Its ENTRY-FUN is a self-pointer.
826 ;; After a component is compiled, we clobber any top level code
827 ;; references to its non-closure XEPs with dummy FUNCTIONAL
828 ;; structures having this kind. This prevents the retained
829 ;; top level code from holding onto the IR for the code it
834 ;; special functions used internally by CATCH and UNWIND-PROTECT.
835 ;; These are pretty much like a normal function (NIL), but are
836 ;; treated specially by local call analysis and stuff. Neither
837 ;; kind should ever be given an XEP even though they appear as
838 ;; args to funny functions. An :ESCAPE function is never actually
839 ;; called, and thus doesn't need to have code generated for it.
842 ;; This function has been found to be uncallable, and has been
843 ;; marked for deletion.
844 (kind nil :type (member nil :optional :deleted :external :toplevel
845 :escape :cleanup :let :mv-let :assignment
847 ;; Is this a function that some external entity (e.g. the fasl dumper)
848 ;; refers to, so that even when it appears to have no references, it
849 ;; shouldn't be deleted? In the old days (before
850 ;; sbcl-0.pre7.37.flaky5.2) this was sort of implicitly true when
851 ;; KIND was :TOPLEVEL. Now it must be set explicitly, both for
852 ;; :TOPLEVEL functions and for any other kind of functions that we
853 ;; want to dump or return from #'CL:COMPILE or whatever.
854 (has-external-references-p nil)
855 ;; In a normal function, this is the external entry point (XEP)
856 ;; lambda for this function, if any. Each function that is used
857 ;; other than in a local call has an XEP, and all of the
858 ;; non-local-call references are replaced with references to the
861 ;; In an XEP lambda (indicated by the :EXTERNAL kind), this is the
862 ;; function that the XEP is an entry-point for. The body contains
863 ;; local calls to all the actual entry points in the function. In a
864 ;; :TOPLEVEL lambda (which is its own XEP) this is a self-pointer.
866 ;; With all other kinds, this is null.
867 (entry-fun nil :type (or functional null))
868 ;; the value of any inline/notinline declaration for a local function
869 (inlinep nil :type inlinep)
870 ;; If we have a lambda that can be used as in inline expansion for
871 ;; this function, then this is it. If there is no source-level
872 ;; lambda corresponding to this function then this is Null (but then
873 ;; INLINEP will always be NIL as well.)
874 (inline-expansion nil :type list)
875 ;; the lexical environment that the inline-expansion should be converted in
876 (lexenv *lexenv* :type lexenv)
877 ;; the original function or macro lambda list, or :UNSPECIFIED if
878 ;; this is a compiler created function
879 (arg-documentation nil :type (or list (member :unspecified)))
880 ;; various rare miscellaneous info that drives code generation & stuff
881 (plist () :type list))
882 (defprinter (functional :identity t)
886 ;;; FUNCTIONAL name operations
887 (defun functional-debug-name (functional)
888 ;; FUNCTIONAL-%DEBUG-NAME takes precedence over FUNCTIONAL-SOURCE-NAME
889 ;; here because we want different debug names for the functions in
890 ;; DEFUN FOO and FLET FOO even though they have the same source name.
891 (or (functional-%debug-name functional)
892 ;; Note that this will cause an error if the function is
893 ;; anonymous. In SBCL (as opposed to CMU CL) we make all
894 ;; FUNCTIONALs have debug names. The CMU CL code didn't bother
895 ;; in many FUNCTIONALs, especially those which were likely to be
896 ;; optimized away before the user saw them. However, getting
897 ;; that right requires a global understanding of the code,
898 ;; which seems bad, so we just require names for everything.
899 (leaf-source-name functional)))
901 ;;; The CLAMBDA only deals with required lexical arguments. Special,
902 ;;; optional, keyword and rest arguments are handled by transforming
903 ;;; into simpler stuff.
904 (def!struct (clambda (:include functional)
906 (:predicate lambda-p)
907 (:constructor make-lambda)
908 (:copier copy-lambda))
909 ;; list of LAMBDA-VAR descriptors for arguments
910 (vars nil :type list :read-only t)
911 ;; If this function was ever a :OPTIONAL function (an entry-point
912 ;; for an OPTIONAL-DISPATCH), then this is that OPTIONAL-DISPATCH.
913 ;; The optional dispatch will be :DELETED if this function is no
915 (optional-dispatch nil :type (or optional-dispatch null))
916 ;; the BIND node for this LAMBDA. This node marks the beginning of
917 ;; the lambda, and serves to explicitly represent the lambda binding
918 ;; semantics within the flow graph representation. This is null in
919 ;; deleted functions, and also in LETs where we deleted the call and
920 ;; bind (because there are no variables left), but have not yet
921 ;; actually deleted the LAMBDA yet.
922 (bind nil :type (or bind null))
923 ;; the RETURN node for this LAMBDA, or NIL if it has been deleted.
924 ;; This marks the end of the lambda, receiving the result of the
925 ;; body. In a LET, the return node is deleted, and the body delivers
926 ;; the value to the actual continuation. The return may also be
927 ;; deleted if it is unreachable.
928 (return nil :type (or creturn null))
929 ;; If this CLAMBDA is a LET, then this slot holds the LAMBDA whose
930 ;; LETS list we are in, otherwise it is a self-pointer.
931 (home nil :type (or clambda null))
932 ;; all the lambdas that have been LET-substituted in this lambda.
933 ;; This is only non-null in lambdas that aren't LETs.
934 (lets nil :type list)
935 ;; all the ENTRY nodes in this function and its LETs, or null in a LET
936 (entries nil :type list)
937 ;; CLAMBDAs which are locally called by this lambda, and other
938 ;; objects (closed-over LAMBDA-VARs and XEPs) which this lambda
939 ;; depends on in such a way that DFO shouldn't put them in separate
941 (calls-or-closes nil :type list)
942 ;; the TAIL-SET that this LAMBDA is in. This is null during creation.
944 ;; In CMU CL, and old SBCL, this was also NILed out when LET
945 ;; conversion happened. That caused some problems, so as of
946 ;; sbcl-0.pre7.37.flaky5.2 when I was trying to get the compiler to
947 ;; emit :EXTERNAL functions directly, and so now the value
948 ;; is no longer NILed out in LET conversion, but instead copied
949 ;; (so that any further optimizations on the rest of the tail
950 ;; set won't modify the value) if necessary.
951 (tail-set nil :type (or tail-set null))
952 ;; the structure which represents the phsical environment that this
953 ;; function's variables are allocated in. This is filled in by
954 ;; physical environment analysis. In a LET, this is EQ to our home's
955 ;; physical environment.
956 (physenv nil :type (or physenv null))
957 ;; In a LET, this is the NODE-LEXENV of the combination node. We
958 ;; retain it so that if the LET is deleted (due to a lack of vars),
959 ;; we will still have caller's lexenv to figure out which cleanup is
961 (call-lexenv nil :type (or lexenv null)))
962 (defprinter (clambda :conc-name lambda- :identity t)
965 (type :test (not (eq type *universal-type*)))
966 (where-from :test (not (eq where-from :assumed)))
967 (vars :prin1 (mapcar #'leaf-source-name vars)))
969 ;;; The OPTIONAL-DISPATCH leaf is used to represent hairy lambdas. It
970 ;;; is a FUNCTIONAL, like LAMBDA. Each legal number of arguments has a
971 ;;; function which is called when that number of arguments is passed.
972 ;;; The function is called with all the arguments actually passed. If
973 ;;; additional arguments are legal, then the LEXPR style MORE-ENTRY
974 ;;; handles them. The value returned by the function is the value
975 ;;; which results from calling the OPTIONAL-DISPATCH.
977 ;;; The theory is that each entry-point function calls the next entry
978 ;;; point tail-recursively, passing all the arguments passed in and
979 ;;; the default for the argument the entry point is for. The last
980 ;;; entry point calls the real body of the function. In the presence
981 ;;; of SUPPLIED-P args and other hair, things are more complicated. In
982 ;;; general, there is a distinct internal function that takes the
983 ;;; SUPPLIED-P args as parameters. The preceding entry point calls
984 ;;; this function with NIL filled in for the SUPPLIED-P args, while
985 ;;; the current entry point calls it with T in the SUPPLIED-P
988 ;;; Note that it is easy to turn a call with a known number of
989 ;;; arguments into a direct call to the appropriate entry-point
990 ;;; function, so functions that are compiled together can avoid doing
992 (def!struct (optional-dispatch (:include functional))
993 ;; the original parsed argument list, for anyone who cares
994 (arglist nil :type list)
995 ;; true if &ALLOW-OTHER-KEYS was supplied
996 (allowp nil :type boolean)
997 ;; true if &KEY was specified (which doesn't necessarily mean that
998 ;; there are any &KEY arguments..)
999 (keyp nil :type boolean)
1000 ;; the number of required arguments. This is the smallest legal
1001 ;; number of arguments.
1002 (min-args 0 :type unsigned-byte)
1003 ;; the total number of required and optional arguments. Args at
1004 ;; positions >= to this are &REST, &KEY or illegal args.
1005 (max-args 0 :type unsigned-byte)
1006 ;; list of the LAMBDAs which are the entry points for non-rest,
1007 ;; non-key calls. The entry for MIN-ARGS is first, MIN-ARGS+1
1008 ;; second, ... MAX-ARGS last. The last entry-point always calls the
1009 ;; main entry; in simple cases it may be the main entry.
1010 (entry-points nil :type list)
1011 ;; an entry point which takes MAX-ARGS fixed arguments followed by
1012 ;; an argument context pointer and an argument count. This entry
1013 ;; point deals with listifying rest args and parsing keywords. This
1014 ;; is null when extra arguments aren't legal.
1015 (more-entry nil :type (or clambda null))
1016 ;; the main entry-point into the function, which takes all arguments
1017 ;; including keywords as fixed arguments. The format of the
1018 ;; arguments must be determined by examining the arglist. This may
1019 ;; be used by callers that supply at least MAX-ARGS arguments and
1020 ;; know what they are doing.
1021 (main-entry nil :type (or clambda null)))
1022 (defprinter (optional-dispatch :identity t)
1025 (type :test (not (eq type *universal-type*)))
1026 (where-from :test (not (eq where-from :assumed)))
1032 (entry-points :test entry-points)
1033 (more-entry :test more-entry)
1036 ;;; The ARG-INFO structure allows us to tack various information onto
1037 ;;; LAMBDA-VARs during IR1 conversion. If we use one of these things,
1038 ;;; then the var will have to be massaged a bit before it is simple
1040 (def!struct arg-info
1041 ;; true if this arg is to be specially bound
1042 (specialp nil :type boolean)
1043 ;; the kind of argument being described. Required args only have arg
1044 ;; info structures if they are special.
1046 :type (member :required :optional :keyword :rest
1047 :more-context :more-count))
1048 ;; If true, this is the VAR for SUPPLIED-P variable of a keyword or
1049 ;; optional arg. This is true for keywords with non-constant
1050 ;; defaults even when there is no user-specified supplied-p var.
1051 (supplied-p nil :type (or lambda-var null))
1052 ;; the default for a keyword or optional, represented as the
1053 ;; original Lisp code. This is set to NIL in &KEY arguments that are
1054 ;; defaulted using the SUPPLIED-P arg.
1055 (default nil :type t)
1056 ;; the actual key for a &KEY argument. Note that in ANSI CL this is
1057 ;; not necessarily a keyword: (DEFUN FOO (&KEY ((BAR BAR))) ...).
1058 (key nil :type symbol))
1059 (defprinter (arg-info :identity t)
1060 (specialp :test specialp)
1062 (supplied-p :test supplied-p)
1063 (default :test default)
1066 ;;; The LAMBDA-VAR structure represents a lexical lambda variable.
1067 ;;; This structure is also used during IR1 conversion to describe
1068 ;;; lambda arguments which may ultimately turn out not to be simple
1071 ;;; LAMBDA-VARs with no REFs are considered to be deleted; physical
1072 ;;; environment analysis isn't done on these variables, so the back
1073 ;;; end must check for and ignore unreferenced variables. Note that a
1074 ;;; deleted LAMBDA-VAR may have sets; in this case the back end is
1075 ;;; still responsible for propagating the SET-VALUE to the set's CONT.
1076 (def!struct (lambda-var (:include basic-var))
1077 ;; true if this variable has been declared IGNORE
1078 (ignorep nil :type boolean)
1079 ;; the CLAMBDA that this var belongs to. This may be null when we are
1080 ;; building a lambda during IR1 conversion.
1081 (home nil :type (or null clambda))
1082 ;; This is set by physical environment analysis if it chooses an
1083 ;; indirect (value cell) representation for this variable because it
1084 ;; is both set and closed over.
1085 (indirect nil :type boolean)
1086 ;; The following two slots are only meaningful during IR1 conversion
1087 ;; of hairy lambda vars:
1089 ;; The ARG-INFO structure which holds information obtained from
1090 ;; &keyword parsing.
1091 (arg-info nil :type (or arg-info null))
1092 ;; if true, the GLOBAL-VAR structure for the special variable which
1093 ;; is to be bound to the value of this argument
1094 (specvar nil :type (or global-var null))
1095 ;; Set of the CONSTRAINTs on this variable. Used by constraint
1096 ;; propagation. This is left null by the lambda pre-pass if it
1097 ;; determine that this is a set closure variable, and is thus not a
1098 ;; good subject for flow analysis.
1099 (constraints nil :type (or sset null)))
1100 (defprinter (lambda-var :identity t)
1102 (type :test (not (eq type *universal-type*)))
1103 (where-from :test (not (eq where-from :assumed)))
1104 (ignorep :test ignorep)
1105 (arg-info :test arg-info)
1106 (specvar :test specvar))
1108 ;;;; basic node types
1110 ;;; A REF represents a reference to a LEAF. REF-REOPTIMIZE is
1111 ;;; initially (and forever) NIL, since REFs don't receive any values
1112 ;;; and don't have any IR1 optimizer.
1113 (defstruct (ref (:include node (:reoptimize nil))
1114 (:constructor make-ref (derived-type leaf))
1116 ;; The leaf referenced.
1117 (leaf nil :type leaf))
1118 (defprinter (ref :identity t)
1121 ;;; Naturally, the IF node always appears at the end of a block.
1122 ;;; NODE-CONT is a dummy continuation, and is there only to keep
1124 (defstruct (cif (:include node)
1127 (:constructor make-if)
1129 ;; CONTINUATION for the predicate
1130 (test (missing-arg) :type continuation)
1131 ;; the blocks that we execute next in true and false case,
1132 ;; respectively (may be the same)
1133 (consequent (missing-arg) :type cblock)
1134 (alternative (missing-arg) :type cblock))
1135 (defprinter (cif :conc-name if- :identity t)
1136 (test :prin1 (continuation-use test))
1140 (defstruct (cset (:include node
1141 (derived-type *universal-type*))
1144 (:constructor make-set)
1146 ;; descriptor for the variable set
1147 (var (missing-arg) :type basic-var)
1148 ;; continuation for the value form
1149 (value (missing-arg) :type continuation))
1150 (defprinter (cset :conc-name set- :identity t)
1152 (value :prin1 (continuation-use value)))
1154 ;;; The BASIC-COMBINATION structure is used to represent both normal
1155 ;;; and multiple value combinations. In a local function call, this
1156 ;;; node appears at the end of its block and the body of the called
1157 ;;; function appears as the successor. The NODE-CONT remains the
1158 ;;; continuation which receives the value of the call.
1159 (defstruct (basic-combination (:include node)
1162 ;; continuation for the function
1163 (fun (missing-arg) :type continuation)
1164 ;; list of CONTINUATIONs for the args. In a local call, an argument
1165 ;; continuation may be replaced with NIL to indicate that the
1166 ;; corresponding variable is unreferenced, and thus no argument
1167 ;; value need be passed.
1168 (args nil :type list)
1169 ;; the kind of function call being made. :LOCAL means that this is a
1170 ;; local call to a function in the same component, and that argument
1171 ;; syntax checking has been done, etc. Calls to known global
1172 ;; functions are represented by storing the FUNCTION-INFO for the
1173 ;; function in this slot. :FULL is a call to an (as yet) unknown
1174 ;; function. :ERROR is like :FULL, but means that we have discovered
1175 ;; that the call contains an error, and should not be reconsidered
1176 ;; for optimization.
1177 (kind :full :type (or (member :local :full :error) function-info))
1178 ;; some kind of information attached to this node by the back end
1181 ;;; The COMBINATION node represents all normal function calls,
1182 ;;; including FUNCALL. This is distinct from BASIC-COMBINATION so that
1183 ;;; an MV-COMBINATION isn't COMBINATION-P.
1184 (defstruct (combination (:include basic-combination)
1185 (:constructor make-combination (fun))
1187 (defprinter (combination :identity t)
1188 (fun :prin1 (continuation-use fun))
1189 (args :prin1 (mapcar (lambda (x)
1191 (continuation-use x)
1195 ;;; An MV-COMBINATION is to MULTIPLE-VALUE-CALL as a COMBINATION is to
1196 ;;; FUNCALL. This is used to implement all the multiple-value
1197 ;;; receiving forms.
1198 (defstruct (mv-combination (:include basic-combination)
1199 (:constructor make-mv-combination (fun))
1201 (defprinter (mv-combination)
1202 (fun :prin1 (continuation-use fun))
1203 (args :prin1 (mapcar #'continuation-use args)))
1205 ;;; The BIND node marks the beginning of a lambda body and represents
1206 ;;; the creation and initialization of the variables.
1207 (defstruct (bind (:include node)
1209 ;; the lambda we are binding variables for. Null when we are
1210 ;; creating the LAMBDA during IR1 translation.
1211 (lambda nil :type (or clambda null)))
1215 ;;; The RETURN node marks the end of a lambda body. It collects the
1216 ;;; return values and represents the control transfer on return. This
1217 ;;; is also where we stick information used for TAIL-SET type
1219 (defstruct (creturn (:include node)
1220 (:conc-name return-)
1221 (:predicate return-p)
1222 (:constructor make-return)
1223 (:copier copy-return))
1224 ;; the lambda we are returning from. Null temporarily during
1226 (lambda nil :type (or clambda null))
1227 ;; the continuation which yields the value of the lambda
1228 (result (missing-arg) :type continuation)
1229 ;; the union of the node-derived-type of all uses of the result
1230 ;; other than by a local call, intersected with the result's
1231 ;; asserted-type. If there are no non-call uses, this is
1233 (result-type *wild-type* :type ctype))
1234 (defprinter (creturn :conc-name return- :identity t)
1238 ;;;; non-local exit support
1240 ;;;; In IR1, we insert special nodes to mark potentially non-local
1243 ;;; The ENTRY node serves to mark the start of the dynamic extent of a
1244 ;;; lexical exit. It is the mess-up node for the corresponding :Entry
1246 (defstruct (entry (:include node)
1248 ;; All of the Exit nodes for potential non-local exits to this point.
1249 (exits nil :type list)
1250 ;; The cleanup for this entry. NULL only temporarily.
1251 (cleanup nil :type (or cleanup null)))
1252 (defprinter (entry :identity t))
1254 ;;; The EXIT node marks the place at which exit code would be emitted,
1255 ;;; if necessary. This is interposed between the uses of the exit
1256 ;;; continuation and the exit continuation's DEST. Instead of using
1257 ;;; the returned value being delivered directly to the exit
1258 ;;; continuation, it is delivered to our VALUE continuation. The
1259 ;;; original exit continuation is the exit node's CONT.
1260 (defstruct (exit (:include node)
1262 ;; the ENTRY node that this is an exit for. If null, this is a
1263 ;; degenerate exit. A degenerate exit is used to "fill" an empty
1264 ;; block (which isn't allowed in IR1.) In a degenerate exit, Value
1265 ;; is always also null.
1266 (entry nil :type (or entry null))
1267 ;; the continuation yielding the value we are to exit with. If NIL,
1268 ;; then no value is desired (as in GO).
1269 (value nil :type (or continuation null)))
1270 (defprinter (exit :identity t)
1272 (value :test value))
1274 ;;;; miscellaneous IR1 structures
1276 (defstruct (undefined-warning
1277 #-no-ansi-print-object
1278 (:print-object (lambda (x s)
1279 (print-unreadable-object (x s :type t)
1280 (prin1 (undefined-warning-name x) s))))
1282 ;; the name of the unknown thing
1283 (name nil :type (or symbol list))
1284 ;; the kind of reference to NAME
1285 (kind (missing-arg) :type (member :function :type :variable))
1286 ;; the number of times this thing was used
1287 (count 0 :type unsigned-byte)
1288 ;; a list of COMPILER-ERROR-CONTEXT structures describing places
1289 ;; where this thing was used. Note that we only record the first
1290 ;; *UNDEFINED-WARNING-LIMIT* calls.
1291 (warnings () :type list))
1293 ;;; a helper for the POLICY macro, defined late here so that the
1294 ;;; various type tests can be inlined
1295 (declaim (ftype (function ((or list lexenv node functional)) list)
1297 (defun %coerce-to-policy (thing)
1298 (let ((result (etypecase thing
1300 (lexenv (lexenv-policy thing))
1301 (node (lexenv-policy (node-lexenv thing)))
1302 (functional (lexenv-policy (functional-lexenv thing))))))
1303 ;; Test the first element of the list as a rudimentary sanity
1304 ;; that it really does look like a valid policy.
1305 (aver (or (null result) (policy-quality-name-p (caar result))))
1309 ;;;; Freeze some structure types to speed type testing.
1312 (declaim (freeze-type node leaf lexenv continuation cblock component cleanup
1313 physenv tail-set nlx-info))