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 default
36 ;; values. A continuation is unused during IR1 conversion until it is
37 ;; assigned a block, and may be also be temporarily unused during
38 ;; later manipulations of IR1. In a consistent state there should
39 ;; never be any mention of :UNUSED continuations. Next can have a
40 ;; non-null value if the next node has already been determined.
43 ;; A continuation that has been deleted from IR1. Any pointers into
44 ;; IR1 are cleared. There are two conditions under which a deleted
45 ;; continuation may appear in code:
46 ;; -- The CONT of the LAST node in a block may be a deleted
47 ;; continuation when the original receiver of the continuation's
48 ;; value was deleted. Note that DEST in a deleted continuation is
49 ;; null, so it is easy to know not to attempt delivering any
50 ;; values to the continuation.
51 ;; -- Unreachable code that hasn't been deleted yet may receive
52 ;; deleted continuations. All such code will be in blocks that
53 ;; have DELETE-P set. All unreachable code is deleted by control
54 ;; optimization, so the backend doesn't have to worry about this.
57 ;; The continuation that is the START of BLOCK. This is the only kind
58 ;; of continuation that can have more than one use. The BLOCK's
59 ;; START-USES is a list of all the uses.
61 ;; :DELETED-BLOCK-START
62 ;; Like :BLOCK-START, but BLOCK has been deleted. A block starting
63 ;; continuation is made into a deleted block start when the block is
64 ;; deleted, but the continuation still may have value semantics.
65 ;; Since there isn't any code left, next is null.
68 ;; A continuation that is the CONT of some node in BLOCK.
69 (kind :unused :type (member :unused :deleted :inside-block :block-start
70 :deleted-block-start))
71 ;; The node which receives this value, if any. In a deleted continuation,
72 ;; this is null even though the node that receives this continuation may not
74 (dest nil :type (or node null))
75 ;; If this is a NODE, then it is the node which is to be evaluated next.
76 ;; This is always null in :DELETED and :UNUSED continuations, and will be
77 ;; null in a :INSIDE-BLOCK continuation when this is the CONT of the LAST.
78 (next nil :type (or node null))
79 ;; An assertion on the type of this continuation's value.
80 (asserted-type *wild-type* :type ctype)
81 ;; Cached type of this continuation's value. If NIL, then this must be
82 ;; recomputed: see CONTINUATION-DERIVED-TYPE.
83 (%derived-type nil :type (or ctype null))
84 ;; Node where this continuation is used, if unique. This is always null in
85 ;; :DELETED and :UNUSED continuations, and is never null in :INSIDE-BLOCK
86 ;; continuations. In a :BLOCK-START continuation, the Block's START-USES
87 ;; indicate whether NIL means no uses or more than one use.
88 (use nil :type (or node null))
89 ;; Basic block this continuation is in. This is null only in :DELETED and
90 ;; :UNUSED continuations. Note that blocks that are unreachable but still in
91 ;; the DFO may receive deleted continuations, so it isn't o.k. to assume that
92 ;; any continuation that you pick up out of its DEST node has a BLOCK.
93 (block nil :type (or cblock null))
94 ;; Set to true when something about this continuation's value has changed.
95 ;; See REOPTIMIZE-CONTINUATION. This provides a way for IR1 optimize to
96 ;; determine which operands to a node have changed. If the optimizer for
97 ;; this node type doesn't care, it can elect not to clear this flag.
98 (reoptimize t :type boolean)
99 ;; An indication of what we have proven about how this contination's type
100 ;; assertion is satisfied:
103 ;; No type check is necessary (proven type is a subtype of the assertion.)
106 ;; A type check is needed.
109 ;; Don't do a type check, but believe (intersect) the assertion. A T
110 ;; check can be changed to :DELETED if we somehow prove the check is
111 ;; unnecessary, or if we eliminate it through a policy decision.
114 ;; Type check generation sets the slot to this if a check is called for,
115 ;; but it believes it has proven that the check won't be done for
116 ;; policy reasons or because a safe implementation will be used. In the
117 ;; latter case, LTN must ensure that a safe implementation *is* be used.
120 ;; There is a compile-time type error in some use of this continuation. A
121 ;; type check should still be generated, but be careful.
123 ;; This is computed lazily by CONTINUATION-DERIVED-TYPE, so use
124 ;; CONTINUATION-TYPE-CHECK instead of the %'ed slot accessor.
125 (%type-check t :type (member t nil :deleted :no-check :error))
126 ;; Something or other that the back end annotates this continuation with.
128 ;; MNA: Re: two obscure bugs in CMU CL
131 ;; Uses of this continuation in the lexical environment. They are recorded
132 ;; so that when one continuation is substituted for another the environment
133 ;; may be updated properly.
135 (lexenv-uses nil :type list)
138 (def!method print-object ((x continuation) stream)
139 (print-unreadable-object (x stream :type t :identity t)))
141 (defstruct (node (:constructor nil))
142 ;; The bottom-up derived type for this node. This does not take into
143 ;; consideration output type assertions on this node (actually on its CONT).
144 (derived-type *wild-type* :type ctype)
145 ;; True if this node needs to be optimized. This is set to true whenever
146 ;; something changes about the value of a continuation whose DEST is this
148 (reoptimize t :type boolean)
149 ;; The continuation which receives the value of this node. This also
150 ;; indicates what we do controlwise after evaluating this node. This may be
151 ;; null during IR1 conversion.
152 (cont nil :type (or continuation null))
153 ;; The continuation that this node is the next of. This is null during
154 ;; IR1 conversion when we haven't linked the node in yet or in nodes that
155 ;; have been deleted from the IR1 by UNLINK-NODE.
156 (prev nil :type (or continuation null))
157 ;; The lexical environment this node was converted in.
158 (lexenv *lexenv* :type lexenv)
159 ;; A representation of the source code responsible for generating this node.
161 ;; For a form introduced by compilation (does not appear in the original
162 ;; source), the path begins with a list of all the enclosing introduced
163 ;; forms. This list is from the inside out, with the form immediately
164 ;; responsible for this node at the head of the list.
166 ;; Following the introduced forms is a representation of the location of the
167 ;; enclosing original source form. This transition is indicated by the magic
168 ;; ORIGINAL-SOURCE-START marker. The first element of the orignal source is
169 ;; the "form number", which is the ordinal number of this form in a
170 ;; depth-first, left-to-right walk of the truly top-level form in which this
173 ;; Following is a list of integers describing the path taken through the
174 ;; source to get to this point:
175 ;; (K L M ...) => (NTH K (NTH L (NTH M ...)))
177 ;; The last element in the list is the top-level form number, which is the
178 ;; ordinal number (in this call to the compiler) of the truly top-level form
179 ;; containing the orignal source.
180 (source-path *current-path* :type list)
181 ;; If this node is in a tail-recursive position, then this is set to T. At
182 ;; the end of IR1 (in environment analysis) this is computed for all nodes
183 ;; (after cleanup code has been emitted). Before then, a non-null value
184 ;; indicates that IR1 optimization has converted a tail local call to a
187 ;; If the back-end breaks tail-recursion for some reason, then it can null
189 (tail-p nil :type boolean))
191 ;;; Flags that are used to indicate various things about a block, such as what
192 ;;; optimizations need to be done on it:
193 ;;; -- REOPTIMIZE is set when something interesting happens the uses of a
194 ;;; continuation whose Dest is in this block. This indicates that the
195 ;;; value-driven (forward) IR1 optimizations should be done on this block.
196 ;;; -- FLUSH-P is set when code in this block becomes potentially flushable,
197 ;;; usually due to a continuation's DEST becoming null.
198 ;;; -- TYPE-CHECK is true when the type check phase should be run on this
199 ;;; block. IR1 optimize can introduce new blocks after type check has
200 ;;; already run. We need to check these blocks, but there is no point in
201 ;;; checking blocks we have already checked.
202 ;;; -- DELETE-P is true when this block is used to indicate that this block
203 ;;; has been determined to be unreachable and should be deleted. IR1
204 ;;; phases should not attempt to examine or modify blocks with DELETE-P
205 ;;; set, since they may:
206 ;;; - be in the process of being deleted, or
207 ;;; - have no successors, or
208 ;;; - receive :DELETED continuations.
209 ;;; -- TYPE-ASSERTED, TEST-MODIFIED
210 ;;; These flags are used to indicate that something in this block might be
211 ;;; of interest to constraint propagation. TYPE-ASSERTED is set when a
212 ;;; continuation type assertion is strengthened. TEST-MODIFIED is set
213 ;;; whenever the test for the ending IF has changed (may be true when there
215 (def-boolean-attribute block
216 reoptimize flush-p type-check delete-p type-asserted test-modified)
218 (macrolet ((frob (slot)
219 `(defmacro ,(symbolicate "BLOCK-" slot) (block)
220 `(block-attributep (block-flags ,block) ,',slot))))
226 (frob test-modified))
228 ;;; The CBLOCK structure represents a basic block. We include SSET-ELEMENT so
229 ;;; that we can have sets of blocks. Initially the SSET-ELEMENT-NUMBER is
230 ;;; null, DFO analysis numbers in reverse DFO. During IR2 conversion, IR1
231 ;;; blocks are re-numbered in forward emit order. This latter numbering also
232 ;;; forms the basis of the block numbering in the debug-info (though that is
233 ;;; relative to the start of the function.)
234 (defstruct (cblock (:include sset-element)
235 (:constructor make-block (start))
236 (:constructor make-block-key)
239 (:copier copy-block))
240 ;; A list of all the blocks that are predecessors/successors of this block.
241 ;; In well-formed IR1, most blocks will have one successor. The only
243 ;; 1. component head blocks (any number)
244 ;; 2. blocks ending in an IF (1 or 2)
245 ;; 3. blocks with DELETE-P set (zero)
246 (pred nil :type list)
247 (succ nil :type list)
248 ;; The continuation which heads this block (either a :Block-Start or
249 ;; :Deleted-Block-Start.) Null when we haven't made the start continuation
250 ;; yet (and in the dummy component head and tail blocks.)
251 (start nil :type (or continuation null))
252 ;; A list of all the nodes that have Start as their Cont.
253 (start-uses nil :type list)
254 ;; The last node in this block. This is null when we are in the process of
255 ;; building a block (and in the dummy component head and tail blocks.)
256 (last nil :type (or node null))
257 ;; The forward and backward links in the depth-first ordering of the blocks.
258 ;; These slots are null at beginning/end.
259 (next nil :type (or null cblock))
260 (prev nil :type (or null cblock))
261 ;; This block's attributes: see above.
262 (flags (block-attributes reoptimize flush-p type-check type-asserted
265 ;; Some sets used by constraint propagation.
270 ;; The component this block is in. Null temporarily during IR1 conversion
271 ;; and in deleted blocks.
272 (component *current-component* :type (or component null))
273 ;; A flag used by various graph-walking code to determine whether this block
274 ;; has been processed already or what. We make this initially NIL so that
275 ;; Find-Initial-DFO doesn't have to scan the entire initial component just to
278 ;; Some kind of info used by the back end.
280 ;; If true, then constraints that hold in this block and its successors by
281 ;; merit of being tested by its IF predecessor.
282 (test-constraint nil :type (or sset null)))
283 (def!method print-object ((cblock cblock) stream)
284 (print-unreadable-object (cblock stream :type t :identity t)
285 (format stream ":START c~D" (cont-num (block-start cblock)))))
287 ;;; The Block-Annotation structure is shared (via :include) by different
288 ;;; block-info annotation structures so that code (specifically control
289 ;;; analysis) can be shared.
290 (defstruct (block-annotation (:constructor nil))
291 ;; The IR1 block that this block is in the Info for.
292 (block (required-argument) :type cblock)
293 ;; The next and previous block in emission order (not DFO). This determines
294 ;; which block we drop though to, and also used to chain together overflow
295 ;; blocks that result from splitting of IR2 blocks in lifetime analysis.
296 (next nil :type (or block-annotation null))
297 (prev nil :type (or block-annotation null)))
299 ;;; The Component structure provides a handle on a connected piece of the flow
300 ;;; graph. Most of the passes in the compiler operate on components rather
301 ;;; than on the entire flow graph.
303 ;; The kind of component:
306 ;; An ordinary component, containing non-top-level code.
309 ;; A component containing only load-time code.
311 ;; :Complex-Top-Level
312 ;; A component containing both top-level and run-time code.
315 ;; The result of initial IR1 conversion, on which component analysis has
319 ;; Debris left over from component analysis.
320 (kind nil :type (member nil :top-level :complex-top-level :initial :deleted))
321 ;; The blocks that are the dummy head and tail of the DFO.
322 ;; Entry/exit points have these blocks as their
323 ;; predecessors/successors. Null temporarily. The start and return
324 ;; from each non-deleted function is linked to the component head
325 ;; and tail. Until environment analysis links NLX entry stubs to the
326 ;; component head, every successor of the head is a function start
327 ;; (i.e. begins with a Bind node.)
328 (head nil :type (or null cblock))
329 (tail nil :type (or null cblock))
330 ;; A list of the CLambda structures for all functions in this
331 ;; component. Optional-Dispatches are represented only by their XEP
332 ;; and other associated lambdas. This doesn't contain any deleted or
334 (lambdas () :type list)
335 ;; A list of Functional structures for functions that are newly
336 ;; converted, and haven't been local-call analyzed yet. Initially
337 ;; functions are not in the Lambdas list. LOCAL-CALL-ANALYZE moves
338 ;; them there (possibly as LETs, or implicitly as XEPs if an
339 ;; OPTIONAL-DISPATCH.) Between runs of LOCAL-CALL-ANALYZE there may
340 ;; be some debris of converted or even deleted functions in this
342 (new-functions () :type list)
343 ;; If true, then there is stuff in this component that could benefit
344 ;; from further IR1 optimization.
345 (reoptimize t :type boolean)
346 ;; If true, then the control flow in this component was messed up by
347 ;; IR1 optimizations. The DFO should be recomputed.
348 (reanalyze nil :type boolean)
349 ;; String that is some sort of name for the code in this component.
350 (name "<unknown>" :type simple-string)
351 ;; Some kind of info used by the back end.
353 ;; The Source-Info structure describing where this component was
355 (source-info *source-info* :type source-info)
356 ;; Count of the number of inline expansions we have done while
357 ;; compiling this component, to detect infinite or exponential
359 (inline-expansions 0 :type index)
360 ;; A hashtable from combination nodes to things describing how an
361 ;; optimization of the node failed. The value is an alist (Transform
362 ;; . Args), where Transform is the structure describing the
363 ;; transform that failed, and Args is either a list of format
364 ;; arguments for the note, or the FUNCTION-TYPE that would have
365 ;; enabled the transformation but failed to match.
366 (failed-optimizations (make-hash-table :test 'eq) :type hash-table)
367 ;; Similar to NEW-FUNCTIONS, but is used when a function has already
368 ;; been analyzed, but new references have been added by inline
369 ;; expansion. Unlike NEW-FUNCTIONS, this is not disjoint from
370 ;; COMPONENT-LAMBDAS.
371 (reanalyze-functions nil :type list))
372 (defprinter (component)
374 (reanalyze :test reanalyze))
376 ;;; The Cleanup structure represents some dynamic binding action.
377 ;;; Blocks are annotated with the current cleanup so that dynamic
378 ;;; bindings can be removed when control is transferred out of the
379 ;;; binding environment. We arrange for changes in dynamic bindings to
380 ;;; happen at block boundaries, so that cleanup code may easily be
381 ;;; inserted. The "mess-up" action is explicitly represented by a
382 ;;; funny function call or Entry node.
384 ;;; We guarantee that cleanups only need to be done at block boundaries
385 ;;; by requiring that the exit continuations initially head their
386 ;;; blocks, and then by not merging blocks when there is a cleanup
389 ;; The kind of thing that has to be cleaned up.
390 (kind (required-argument)
391 :type (member :special-bind :catch :unwind-protect :block :tagbody))
392 ;; The node that messes things up. This is the last node in the
393 ;; non-messed-up environment. Null only temporarily. This could be
394 ;; deleted due to unreachability.
395 (mess-up nil :type (or node null))
396 ;; A list of all the NLX-Info structures whose NLX-Info-Cleanup is
397 ;; this cleanup. This is filled in by environment analysis.
398 (nlx-info nil :type list))
399 (defprinter (cleanup)
402 (nlx-info :test nlx-info))
404 ;;; The Environment structure represents the result of Environment analysis.
405 (defstruct environment
406 ;; The function that allocates this environment.
407 (function (required-argument) :type clambda)
408 ;; A list of all the Lambdas that allocate variables in this environment.
409 (lambdas nil :type list)
410 ;; A list of all the lambda-vars and NLX-Infos needed from enclosing
411 ;; environments by code in this environment.
412 (closure nil :type list)
413 ;; A list of NLX-Info structures describing all the non-local exits into this
415 (nlx-info nil :type list)
416 ;; Some kind of info used by the back end.
418 (defprinter (environment)
420 (closure :test closure)
421 (nlx-info :test nlx-info))
423 ;;; The Tail-Set structure is used to accmumlate information about
424 ;;; tail-recursive local calls. The "tail set" is effectively the transitive
425 ;;; closure of the "is called tail-recursively by" relation.
427 ;;; All functions in the same tail set share the same Tail-Set structure.
428 ;;; Initially each function has its own Tail-Set, but when IR1-OPTIMIZE-RETURN
429 ;;; notices a tail local call, it joins the tail sets of the called function
430 ;;; and the calling function.
432 ;;; The tail set is somewhat approximate, because it is too early to be sure
433 ;;; which calls will be TR. Any call that *might* end up TR causes tail-set
436 ;; A list of all the lambdas in this tail set.
437 (functions nil :type list)
438 ;; Our current best guess of the type returned by these functions. This is
439 ;; the union across all the functions of the return node's Result-Type.
440 ;; excluding local calls.
441 (type *wild-type* :type ctype)
442 ;; Some info used by the back end.
444 (defprinter (tail-set)
449 ;;; The NLX-Info structure is used to collect various information about
450 ;;; non-local exits. This is effectively an annotation on the Continuation,
451 ;;; although it is accessed by searching in the Environment-Nlx-Info.
452 (def!struct (nlx-info (:make-load-form-fun ignore-it))
453 ;; The cleanup associated with this exit. In a catch or unwind-protect, this
454 ;; is the :Catch or :Unwind-Protect cleanup, and not the cleanup for the
455 ;; escape block. The Cleanup-Kind of this thus provides a good indication of
456 ;; what kind of exit is being done.
457 (cleanup (required-argument) :type cleanup)
458 ;; The continuation exited to (the CONT of the EXIT nodes.) If this exit is
459 ;; from an escape function (CATCH or UNWIND-PROTECT), then environment
460 ;; analysis deletes the escape function and instead has the %NLX-ENTRY use
461 ;; this continuation.
463 ;; This slot is primarily an indication of where this exit delivers its
464 ;; values to (if any), but it is also used as a sort of name to allow us to
465 ;; find the NLX-Info that corresponds to a given exit. For this purpose, the
466 ;; Entry must also be used to disambiguate, since exits to different places
467 ;; may deliver their result to the same continuation.
468 (continuation (required-argument) :type continuation)
469 ;; The entry stub inserted by environment analysis. This is a block
470 ;; containing a call to the %NLX-Entry funny function that has the original
471 ;; exit destination as its successor. Null only temporarily.
472 (target nil :type (or cblock null))
473 ;; Some kind of info used by the back end.
475 (defprinter (nlx-info)
482 ;;; Variables, constants and functions are all represented by LEAF
483 ;;; structures. A reference to a LEAF is indicated by a REF node. This
484 ;;; allows us to easily substitute one for the other without actually
485 ;;; hacking the flow graph.
486 (def!struct (leaf (:make-load-form-fun ignore-it)
488 ;; Some name for this leaf. The exact significance of the name
489 ;; depends on what kind of leaf it is. In a Lambda-Var or
490 ;; Global-Var, this is the symbol name of the variable. In a
491 ;; functional that is from a DEFUN, this is the defined name. In
492 ;; other functionals, this is a descriptive string.
494 ;; The type which values of this leaf must have.
495 (type *universal-type* :type ctype)
496 ;; Where the Type information came from:
497 ;; :DECLARED, from a declaration.
498 ;; :ASSUMED, from uses of the object.
499 ;; :DEFINED, from examination of the definition.
500 ;; FIXME: This should be a named type. (LEAF-WHERE-FROM?)
501 (where-from :assumed :type (member :declared :assumed :defined))
502 ;; List of the Ref nodes for this leaf.
504 ;; True if there was ever a Ref or Set node for this leaf. This may
505 ;; be true when Refs and Sets are null, since code can be deleted.
506 (ever-used nil :type boolean)
507 ;; Some kind of info used by the back end.
510 ;;; The Constant structure is used to represent known constant values.
511 ;;; If Name is not null, then it is the name of the named constant
512 ;;; which this leaf corresponds to, otherwise this is an anonymous
514 (def!struct (constant (:include leaf))
515 ;; The value of the constant.
517 (defprinter (constant)
521 ;;; The Basic-Var structure represents information common to all
522 ;;; variables which don't correspond to known local functions.
523 (def!struct (basic-var (:include leaf) (:constructor nil))
524 ;; Lists of the set nodes for this variable.
525 (sets () :type list))
527 ;;; The Global-Var structure represents a value hung off of the symbol
528 ;;; Name. We use a :Constant Var when we know that the thing is a
529 ;;; constant, but don't know what the value is at compile time.
530 (def!struct (global-var (:include basic-var))
531 ;; Kind of variable described.
532 (kind (required-argument)
533 :type (member :special :global-function :constant :global)))
534 (defprinter (global-var)
536 (type :test (not (eq type *universal-type*)))
537 (where-from :test (not (eq where-from :assumed)))
540 ;;; The Slot-Accessor structure represents slot accessor functions. It
541 ;;; is a subtype of Global-Var to make it look more like a normal
543 (def!struct (slot-accessor (:include global-var
544 (where-from :defined)
545 (kind :global-function)))
546 ;; The description of the structure that this is an accessor for.
547 (for (required-argument) :type sb!xc:class)
548 ;; The slot description of the slot.
549 (slot (required-argument)))
550 (defprinter (slot-accessor)
555 ;;; The Defined-Function structure represents functions that are
556 ;;; defined in the same compilation block, or that have inline
557 ;;; expansions, or have a non-NIL INLINEP value. Whenever we change
558 ;;; the INLINEP state (i.e. an inline proclamation) we copy the
559 ;;; structure so that former inlinep values are preserved.
560 (def!struct (defined-function (:include global-var
561 (where-from :defined)
562 (kind :global-function)))
563 ;; The values of INLINEP and INLINE-EXPANSION initialized from the
564 ;; global environment.
565 (inlinep nil :type inlinep)
566 (inline-expansion nil :type (or cons null))
567 ;; The block-local definition of this function (either because it
568 ;; was semi-inline, or because it was defined in this block.) If
569 ;; this function is not an entry point, then this may be deleted or
570 ;; let-converted. Null if we haven't converted the expansion yet.
571 (functional nil :type (or functional null)))
572 (defprinter (defined-function)
575 (functional :test functional))
579 ;;; We default the WHERE-FROM and TYPE slots to :DEFINED and FUNCTION.
580 ;;; We don't normally manipulate function types for defined functions,
581 ;;; but if someone wants to know, an approximation is there.
582 (def!struct (functional (:include leaf
583 (where-from :defined)
584 (type (specifier-type 'function))))
585 ;; Some information about how this function is used. These values are
589 ;; An ordinary function, callable using local call.
592 ;; A lambda that is used in only one local call, and has in effect
593 ;; been substituted directly inline. The return node is deleted, and
594 ;; the result is computed with the actual result continuation for the
598 ;; Similar to :Let, but the call is an MV-Call.
601 ;; Similar to a let, but can have other than one call as long as there
602 ;; is at most one non-tail call.
605 ;; A lambda that is an entry-point for an optional-dispatch. Similar
606 ;; to NIL, but requires greater caution, since local call analysis may
607 ;; create new references to this function. Also, the function cannot
608 ;; be deleted even if it has *no* references. The Optional-Dispatch
609 ;; is in the LAMDBA-OPTIONAL-DISPATCH.
612 ;; An external entry point lambda. The function it is an entry for is
613 ;; in the Entry-Function.
616 ;; A top-level lambda, holding a compiled top-level form. Compiled
617 ;; very much like NIL, but provides an indication of top-level
618 ;; context. A top-level lambda should have *no* references. Its
619 ;; Entry-Function is a self-pointer.
622 ;; After a component is compiled, we clobber any top-level code
623 ;; references to its non-closure XEPs with dummy FUNCTIONAL structures
624 ;; having this kind. This prevents the retained top-level code from
625 ;; holding onto the IR for the code it references.
629 ;; Special functions used internally by Catch and Unwind-Protect.
630 ;; These are pretty much like a normal function (NIL), but are treated
631 ;; specially by local call analysis and stuff. Neither kind should
632 ;; ever be given an XEP even though they appear as args to funny
633 ;; functions. An :Escape function is never actually called, and thus
634 ;; doesn't need to have code generated for it.
637 ;; This function has been found to be uncallable, and has been
638 ;; marked for deletion.
639 (kind nil :type (member nil :optional :deleted :external :top-level :escape
640 :cleanup :let :mv-let :assignment
642 ;; In a normal function, this is the external entry point (XEP)
643 ;; lambda for this function, if any. Each function that is used
644 ;; other than in a local call has an XEP, and all of the
645 ;; non-local-call references are replaced with references to the
648 ;; In an XEP lambda (indicated by the :External kind), this is the
649 ;; function that the XEP is an entry-point for. The body contains
650 ;; local calls to all the actual entry points in the function. In a
651 ;; :Top-Level lambda (which is its own XEP) this is a self-pointer.
653 ;; With all other kinds, this is null.
654 (entry-function nil :type (or functional null))
655 ;; The value of any inline/notinline declaration for a local function.
656 (inlinep nil :type inlinep)
657 ;; If we have a lambda that can be used as in inline expansion for this
658 ;; function, then this is it. If there is no source-level lambda
659 ;; corresponding to this function then this is Null (but then INLINEP will
660 ;; always be NIL as well.)
661 (inline-expansion nil :type list)
662 ;; The lexical environment that the inline-expansion should be converted in.
663 (lexenv *lexenv* :type lexenv)
664 ;; The original function or macro lambda list, or :UNSPECIFIED if this is a
665 ;; compiler created function.
666 (arg-documentation nil :type (or list (member :unspecified)))
667 ;; Various rare miscellaneous info that drives code generation & stuff.
668 (plist () :type list))
669 (defprinter (functional)
672 ;;; The Lambda only deals with required lexical arguments. Special,
673 ;;; optional, keyword and rest arguments are handled by transforming
674 ;;; into simpler stuff.
675 (def!struct (clambda (:include functional)
677 (:predicate lambda-p)
678 (:constructor make-lambda)
679 (:copier copy-lambda))
680 ;; List of lambda-var descriptors for args.
681 (vars nil :type list)
682 ;; If this function was ever a :OPTIONAL function (an entry-point
683 ;; for an optional-dispatch), then this is that optional-dispatch.
684 ;; The optional dispatch will be :DELETED if this function is no
686 (optional-dispatch nil :type (or optional-dispatch null))
687 ;; The Bind node for this Lambda. This node marks the beginning of
688 ;; the lambda, and serves to explicitly represent the lambda binding
689 ;; semantics within the flow graph representation. Null in deleted
690 ;; functions, and also in LETs where we deleted the call & bind
691 ;; (because there are no variables left), but have not yet actually
692 ;; deleted the lambda yet.
693 (bind nil :type (or bind null))
694 ;; The Return node for this Lambda, or NIL if it has been deleted.
695 ;; This marks the end of the lambda, receiving the result of the
696 ;; body. In a let, the return node is deleted, and the body delivers
697 ;; the value to the actual continuation. The return may also be
698 ;; deleted if it is unreachable.
699 (return nil :type (or creturn null))
700 ;; If this is a let, then the Lambda whose Lets list we are in,
701 ;; otherwise this is a self-pointer.
702 (home nil :type (or clambda null))
703 ;; A list of all the all the lambdas that have been let-substituted
704 ;; in this lambda. This is only non-null in lambdas that aren't
707 ;; A list of all the Entry nodes in this function and its lets. Null
709 (entries () :type list)
710 ;; A list of all the functions directly called from this function
711 ;; (or one of its lets) using a non-let local call. May include
712 ;; deleted functions because nobody bothers to clear them out.
713 (calls () :type list)
714 ;; The Tail-Set that this lambda is in. Null during creation and in
716 (tail-set nil :type (or tail-set null))
717 ;; The structure which represents the environment that this
718 ;; Function's variables are allocated in. This is filled in by
719 ;; environment analysis. In a let, this is EQ to our home's
721 (environment nil :type (or environment null))
722 ;; In a LET, this is the NODE-LEXENV of the combination node. We
723 ;; retain it so that if the let is deleted (due to a lack of vars),
724 ;; we will still have caller's lexenv to figure out which cleanup is
726 (call-lexenv nil :type (or lexenv null)))
727 (defprinter (clambda :conc-name lambda-)
729 (type :test (not (eq type *universal-type*)))
730 (where-from :test (not (eq where-from :assumed)))
731 (vars :prin1 (mapcar #'leaf-name vars)))
733 ;;; The Optional-Dispatch leaf is used to represent hairy lambdas. It
734 ;;; is a Functional, like Lambda. Each legal number of arguments has a
735 ;;; function which is called when that number of arguments is passed.
736 ;;; The function is called with all the arguments actually passed. If
737 ;;; additional arguments are legal, then the LEXPR style More-Entry
738 ;;; handles them. The value returned by the function is the value
739 ;;; which results from calling the Optional-Dispatch.
741 ;;; The theory is that each entry-point function calls the next entry
742 ;;; point tail-recursively, passing all the arguments passed in and
743 ;;; the default for the argument the entry point is for. The last
744 ;;; entry point calls the real body of the function. In the presence
745 ;;; of supplied-p args and other hair, things are more complicated. In
746 ;;; general, there is a distinct internal function that takes the
747 ;;; supplied-p args as parameters. The preceding entry point calls
748 ;;; this function with NIL filled in for the supplied-p args, while
749 ;;; the current entry point calls it with T in the supplied-p
752 ;;; Note that it is easy to turn a call with a known number of
753 ;;; arguments into a direct call to the appropriate entry-point
754 ;;; function, so functions that are compiled together can avoid doing
756 (def!struct (optional-dispatch (:include functional))
757 ;; The original parsed argument list, for anyone who cares.
758 (arglist nil :type list)
759 ;; True if &ALLOW-OTHER-KEYS was supplied.
760 (allowp nil :type boolean)
761 ;; True if &KEY was specified. (Doesn't necessarily mean that there
762 ;; are any keyword arguments...)
763 (keyp nil :type boolean)
764 ;; The number of required arguments. This is the smallest legal
765 ;; number of arguments.
766 (min-args 0 :type unsigned-byte)
767 ;; The total number of required and optional arguments. Args at
768 ;; positions >= to this are rest, key or illegal args.
769 (max-args 0 :type unsigned-byte)
770 ;; List of the Lambdas which are the entry points for non-rest,
771 ;; non-key calls. The entry for Min-Args is first, Min-Args+1
772 ;; second, ... Max-Args last. The last entry-point always calls the
773 ;; main entry; in simple cases it may be the main entry.
774 (entry-points nil :type list)
775 ;; An entry point which takes Max-Args fixed arguments followed by
776 ;; an argument context pointer and an argument count. This entry
777 ;; point deals with listifying rest args and parsing keywords. This
778 ;; is null when extra arguments aren't legal.
779 (more-entry nil :type (or clambda null))
780 ;; The main entry-point into the function, which takes all arguments
781 ;; including keywords as fixed arguments. The format of the
782 ;; arguments must be determined by examining the arglist. This may
783 ;; be used by callers that supply at least Max-Args arguments and
784 ;; know what they are doing.
785 (main-entry nil :type (or clambda null)))
786 (defprinter (optional-dispatch)
788 (type :test (not (eq type *universal-type*)))
789 (where-from :test (not (eq where-from :assumed)))
795 (entry-points :test entry-points)
796 (more-entry :test more-entry)
799 ;;; The Arg-Info structure allows us to tack various information onto
800 ;;; Lambda-Vars during IR1 conversion. If we use one of these things,
801 ;;; then the var will have to be massaged a bit before it is simple
804 ;; True if this arg is to be specially bound.
805 (specialp nil :type boolean)
806 ;; The kind of argument being described. Required args only have arg
807 ;; info structures if they are special.
808 (kind (required-argument) :type (member :required :optional :keyword :rest
809 :more-context :more-count))
810 ;; If true, the Var for supplied-p variable of a keyword or optional
811 ;; arg. This is true for keywords with non-constant defaults even
812 ;; when there is no user-specified supplied-p var.
813 (supplied-p nil :type (or lambda-var null))
814 ;; The default for a keyword or optional, represented as the
815 ;; original Lisp code. This is set to NIL in keyword arguments that
816 ;; are defaulted using the supplied-p arg.
817 (default nil :type t)
818 ;; The actual keyword for a keyword argument.
819 (keyword nil :type (or keyword null)))
820 (defprinter (arg-info)
821 (specialp :test specialp)
823 (supplied-p :test supplied-p)
824 (default :test default)
825 (keyword :test keyword))
827 ;;; The Lambda-Var structure represents a lexical lambda variable.
828 ;;; This structure is also used during IR1 conversion to describe
829 ;;; lambda arguments which may ultimately turn out not to be simple
832 ;;; Lambda-Vars with no Refs are considered to be deleted; environment
833 ;;; analysis isn't done on these variables, so the back end must check
834 ;;; for and ignore unreferenced variables. Note that a deleted
835 ;;; lambda-var may have sets; in this case the back end is still
836 ;;; responsible for propagating the Set-Value to the set's Cont.
837 (def!struct (lambda-var (:include basic-var))
838 ;; True if this variable has been declared Ignore.
839 (ignorep nil :type boolean)
840 ;; The Lambda that this var belongs to. This may be null when we are
841 ;; building a lambda during IR1 conversion.
842 (home nil :type (or null clambda))
843 ;; This is set by environment analysis if it chooses an indirect
844 ;; (value cell) representation for this variable because it is both
845 ;; set and closed over.
846 (indirect nil :type boolean)
847 ;; The following two slots are only meaningful during IR1 conversion
848 ;; of hairy lambda vars:
850 ;; The Arg-Info structure which holds information obtained from
852 (arg-info nil :type (or arg-info null))
853 ;; If true, the Global-Var structure for the special variable which
854 ;; is to be bound to the value of this argument.
855 (specvar nil :type (or global-var null))
856 ;; Set of the CONSTRAINTs on this variable. Used by constraint
857 ;; propagation. This is left null by the lambda pre-pass if it
858 ;; determine that this is a set closure variable, and is thus not a
859 ;; good subject for flow analysis.
860 (constraints nil :type (or sset null)))
861 (defprinter (lambda-var)
863 (type :test (not (eq type *universal-type*)))
864 (where-from :test (not (eq where-from :assumed)))
865 (ignorep :test ignorep)
866 (arg-info :test arg-info)
867 (specvar :test specvar))
869 ;;;; basic node types
871 ;;; A Ref represents a reference to a leaf. Ref-Reoptimize is
872 ;;; initially (and forever) NIL, since Refs don't receive any values
873 ;;; and don't have any IR1 optimizer.
874 (defstruct (ref (:include node (:reoptimize nil))
875 (:constructor make-ref (derived-type leaf)))
876 ;; The leaf referenced.
877 (leaf nil :type leaf))
881 ;;; Naturally, the IF node always appears at the end of a block.
882 ;;; Node-Cont is a dummy continuation, and is there only to keep
884 (defstruct (cif (:include node)
887 (:constructor make-if)
889 ;; Continuation for the predicate.
890 (test (required-argument) :type continuation)
891 ;; The blocks that we execute next in true and false case,
892 ;; respectively (may be the same.)
893 (consequent (required-argument) :type cblock)
894 (alternative (required-argument) :type cblock))
895 (defprinter (cif :conc-name if-)
896 (test :prin1 (continuation-use test))
900 (defstruct (cset (:include node
901 (derived-type *universal-type*))
904 (:constructor make-set)
906 ;; Descriptor for the variable set.
907 (var (required-argument) :type basic-var)
908 ;; Continuation for the value form.
909 (value (required-argument) :type continuation))
910 (defprinter (cset :conc-name set-)
912 (value :prin1 (continuation-use value)))
914 ;;; The Basic-Combination structure is used to represent both normal
915 ;;; and multiple value combinations. In a local function call, this
916 ;;; node appears at the end of its block and the body of the called
917 ;;; function appears as the successor. The NODE-CONT remains the
918 ;;; continuation which receives the value of the call.
919 (defstruct (basic-combination (:include node)
921 ;; Continuation for the function.
922 (fun (required-argument) :type continuation)
923 ;; List of continuations for the args. In a local call, an argument
924 ;; continuation may be replaced with NIL to indicate that the
925 ;; corresponding variable is unreferenced, and thus no argument
926 ;; value need be passed.
927 (args nil :type list)
928 ;; The kind of function call being made. :LOCAL means that this is a
929 ;; local call to a function in the same component, and that argument
930 ;; syntax checking has been done, etc. Calls to known global
931 ;; functions are represented by storing the FUNCTION-INFO for the
932 ;; function in this slot. :FULL is a call to an (as yet) unknown
933 ;; function. :ERROR is like :FULL, but means that we have discovered
934 ;; that the call contains an error, and should not be reconsidered
936 (kind :full :type (or (member :local :full :error) function-info))
937 ;; Some kind of information attached to this node by the back end.
940 ;;; The COMBINATION node represents all normal function calls,
941 ;;; including FUNCALL. This is distinct from BASIC-COMBINATION so that
942 ;;; an MV-COMBINATION isn't COMBINATION-P.
943 (defstruct (combination (:include basic-combination)
944 (:constructor make-combination (fun))))
945 (defprinter (combination)
946 (fun :prin1 (continuation-use fun))
947 (args :prin1 (mapcar #'(lambda (x)
953 ;;; An MV-Combination is to Multiple-Value-Call as a Combination is to
954 ;;; Funcall. This is used to implement all the multiple-value
956 (defstruct (mv-combination (:include basic-combination)
957 (:constructor make-mv-combination (fun))))
958 (defprinter (mv-combination)
959 (fun :prin1 (continuation-use fun))
960 (args :prin1 (mapcar #'continuation-use args)))
962 ;;; The Bind node marks the beginning of a lambda body and represents
963 ;;; the creation and initialization of the variables.
964 (defstruct (bind (:include node))
965 ;; The lambda we are binding variables for. Null when we are
966 ;; creating the Lambda during IR1 translation.
967 (lambda nil :type (or clambda null)))
971 ;;; The Return node marks the end of a lambda body. It collects the
972 ;;; return values and represents the control transfer on return. This
973 ;;; is also where we stick information used for Tail-Set type
975 (defstruct (creturn (:include node)
977 (:predicate return-p)
978 (:constructor make-return)
979 (:copier copy-return))
980 ;; The lambda we are returning from. Null temporarily during
982 (lambda nil :type (or clambda null))
983 ;; The continuation which yields the value of the lambda.
984 (result (required-argument) :type continuation)
985 ;; The union of the node-derived-type of all uses of the result
986 ;; other than by a local call, intersected with the result's
987 ;; asserted-type. If there are no non-call uses, this is
989 (result-type *wild-type* :type ctype))
990 (defprinter (creturn :conc-name return-)
994 ;;;; non-local exit support
996 ;;;; In IR1, we insert special nodes to mark potentially non-local
999 ;;; The Entry node serves to mark the start of the dynamic extent of a
1000 ;;; lexical exit. It is the mess-up node for the corresponding :Entry
1002 (defstruct (entry (:include node))
1003 ;; All of the Exit nodes for potential non-local exits to this point.
1004 (exits nil :type list)
1005 ;; The cleanup for this entry. Null only temporarily.
1006 (cleanup nil :type (or cleanup null)))
1007 (defprinter (entry))
1009 ;;; The Exit node marks the place at which exit code would be emitted,
1010 ;;; if necessary. This is interposed between the uses of the exit
1011 ;;; continuation and the exit continuation's DEST. Instead of using
1012 ;;; the returned value being delivered directly to the exit
1013 ;;; continuation, it is delivered to our Value continuation. The
1014 ;;; original exit continuation is the exit node's CONT.
1015 (defstruct (exit (:include node))
1016 ;; The Entry node that this is an exit for. If null, this is a
1017 ;; degenerate exit. A degenerate exit is used to "fill" an empty
1018 ;; block (which isn't allowed in IR1.) In a degenerate exit, Value
1019 ;; is always also null.
1020 (entry nil :type (or entry null))
1021 ;; The continuation yeilding the value we are to exit with. If NIL,
1022 ;; then no value is desired (as in GO).
1023 (value nil :type (or continuation null)))
1026 (value :test value))
1028 ;;;; miscellaneous IR1 structures
1030 (defstruct (undefined-warning
1031 #-no-ansi-print-object
1032 (:print-object (lambda (x s)
1033 (print-unreadable-object (x s :type t)
1034 (prin1 (undefined-warning-name x) s)))))
1035 ;; The name of the unknown thing.
1036 (name nil :type (or symbol list))
1037 ;; The kind of reference to Name.
1038 (kind (required-argument) :type (member :function :type :variable))
1039 ;; The number of times this thing was used.
1040 (count 0 :type unsigned-byte)
1041 ;; A list of COMPILER-ERROR-CONTEXT structures describing places
1042 ;; where this thing was used. Note that we only record the first
1043 ;; *UNDEFINED-WARNING-LIMIT* calls.
1044 (warnings () :type list))
1046 ;;;; Freeze some structure types to speed type testing.
1049 (declaim (freeze-type node leaf lexenv continuation cblock component cleanup
1050 environment tail-set nlx-info))