(in-package "SB!C")
-(file-comment
- "$Header$")
-
;;; This function propagates information from the variables in the function
;;; Fun to the actual arguments in Call. This is also called by the VALUES IR1
;;; optimizer when it sleazily converts MV-BINDs to LETs.
\f
;;;; external entry point creation
-;;; Return a Lambda form that can be used as the definition of the XEP for Fun.
+;;; Return a Lambda form that can be used as the definition of the XEP
+;;; for FUN.
;;;
-;;; If Fun is a lambda, then we check the number of arguments (conditional
-;;; on policy) and call Fun with all the arguments.
+;;; If FUN is a lambda, then we check the number of arguments
+;;; (conditional on policy) and call FUN with all the arguments.
;;;
-;;; If Fun is an Optional-Dispatch, then we dispatch off of the number of
-;;; supplied arguments by doing do an = test for each entry-point, calling the
-;;; entry with the appropriate prefix of the passed arguments.
+;;; If FUN is an OPTIONAL-DISPATCH, then we dispatch off of the number
+;;; of supplied arguments by doing do an = test for each entry-point,
+;;; calling the entry with the appropriate prefix of the passed
+;;; arguments.
;;;
-;;; If there is a more arg, then there are a couple of optimizations that we
-;;; make (more for space than anything else):
-;;; -- If Min-Args is 0, then we make the more entry a T clause, since no
-;;; argument count error is possible.
-;;; -- We can omit the = clause for the last entry-point, allowing the case of
-;;; 0 more args to fall through to the more entry.
+;;; If there is a more arg, then there are a couple of optimizations
+;;; that we make (more for space than anything else):
+;;; -- If MIN-ARGS is 0, then we make the more entry a T clause, since
+;;; no argument count error is possible.
+;;; -- We can omit the = clause for the last entry-point, allowing the
+;;; case of 0 more args to fall through to the more entry.
;;;
-;;; We don't bother to policy conditionalize wrong arg errors in optional
-;;; dispatches, since the additional overhead is negligible compared to the
-;;; other hair going down.
+;;; We don't bother to policy conditionalize wrong arg errors in
+;;; optional dispatches, since the additional overhead is negligible
+;;; compared to the cost of everything else going on.
;;;
-;;; Note that if policy indicates it, argument type declarations in Fun will
-;;; be verified. Since nothing is known about the type of the XEP arg vars,
-;;; type checks will be emitted when the XEP's arg vars are passed to the
-;;; actual function.
+;;; Note that if policy indicates it, argument type declarations in
+;;; Fun will be verified. Since nothing is known about the type of the
+;;; XEP arg vars, type checks will be emitted when the XEP's arg vars
+;;; are passed to the actual function.
(defun make-xep-lambda (fun)
(declare (type functional fun))
(etypecase fun
(entries `((= ,n-supplied ,n)
(%funcall ,(first eps) ,@(subseq temps 0 n)))))
`(lambda (,n-supplied ,@temps)
- ;; FIXME: Make sure that INDEX type distinguishes between target
- ;; and host. (Probably just make the SB!XC:DEFTYPE different from
- ;; CL:DEFTYPE.)
+ ;; FIXME: Make sure that INDEX type distinguishes between
+ ;; target and host. (Probably just make the SB!XC:DEFTYPE
+ ;; different from CL:DEFTYPE.)
(declare (type index ,n-supplied))
(cond
,@(if more (butlast (entries)) (entries))
,@(when more
- `((,(if (zerop min) 't `(>= ,n-supplied ,max))
+ `((,(if (zerop min) t `(>= ,n-supplied ,max))
,(let ((n-context (gensym))
(n-count (gensym)))
`(multiple-value-bind (,n-context ,n-count)
(t
(%argument-count-error ,n-supplied)))))))))
-;;; Make an external entry point (XEP) for Fun and return it. We
-;;; convert the result of Make-XEP-Lambda in the correct environment,
-;;; then associate this lambda with Fun as its XEP. After the
+;;; Make an external entry point (XEP) for FUN and return it. We
+;;; convert the result of MAKE-XEP-LAMBDA in the correct environment,
+;;; then associate this lambda with FUN as its XEP. After the
;;; conversion, we iterate over the function's associated lambdas,
;;; redoing local call analysis so that the XEP calls will get
-;;; converted. We also bind *LEXENV* to change the compilation policy
-;;; over to the interface policy.
+;;; converted.
;;;
-;;; We set Reanalyze and Reoptimize in the component, just in case we
+;;; We set REANALYZE and REOPTIMIZE in the component, just in case we
;;; discover an XEP after the initial local call analyze pass.
(defun make-external-entry-point (fun)
(declare (type functional fun))
- (assert (not (functional-entry-function fun)))
+ (aver (not (functional-entry-function fun)))
(with-ir1-environment (lambda-bind (main-entry fun))
- (let* ((*lexenv* (make-lexenv :cookie (make-interface-cookie *lexenv*)))
- (res (ir1-convert-lambda (make-xep-lambda fun))))
- (setf (functional-kind res) :external)
- (setf (leaf-ever-used res) t)
- (setf (functional-entry-function res) fun)
- (setf (functional-entry-function fun) res)
- (setf (component-reanalyze *current-component*) t)
- (setf (component-reoptimize *current-component*) t)
+ (let ((res (ir1-convert-lambda (make-xep-lambda fun))))
+ (setf (functional-kind res) :external
+ (leaf-ever-used res) t
+ (functional-entry-function res) fun
+ (functional-entry-function fun) res
+ (component-reanalyze *current-component*) t
+ (component-reoptimize *current-component*) t)
(etypecase fun
(clambda (local-call-analyze-1 fun))
(optional-dispatch
(values))
-;;; If policy is auspicious, Call is not in an XEP, and we don't seem
+;;; If policy is auspicious, CALL is not in an XEP, and we don't seem
;;; to be in an infinite recursive loop, then change the reference to
;;; reference a fresh copy. We return whichever function we decide to
;;; reference.
(defun maybe-expand-local-inline (fun ref call)
- (if (and (policy call (>= speed space) (>= speed cspeed))
+ (if (and (policy call
+ (and (>= speed space) (>= speed compilation-speed)))
(not (eq (functional-kind (node-home-lambda call)) :external))
(not *converting-for-interpreter*)
(inline-expansion-ok call))
(won nil)
(res (catch 'local-call-lossage
(prog1
- (ir1-convert-lambda (functional-inline-expansion fun))
+ (ir1-convert-lambda (functional-inline-expansion
+ fun))
(setq won t)))))
(cond (won
(change-ref-leaf ref res)
(let* ((block (node-block call))
(component (block-component block))
(original-fun (ref-leaf ref)))
- (assert (functional-p original-fun))
+ (aver (functional-p original-fun))
(unless (or (member (basic-combination-kind call) '(:local :error))
(block-delete-p block)
(eq (functional-kind (block-home-lambda block)) :deleted)
(rest (leaf-refs original-fun)))
(setq fun (maybe-expand-local-inline fun ref call)))
- (assert (member (functional-kind fun)
- '(nil :escape :cleanup :optional)))
+ (aver (member (functional-kind fun)
+ '(nil :escape :cleanup :optional)))
(cond ((mv-combination-p call)
(convert-mv-call ref call fun))
((lambda-p fun)
;; but as long as we continue to use that policy, that's the
;; not our biggest problem.:-| When we fix that policy, this
;; should come back into compliance. (So fix that policy!)
+ ;; ..but..
+ ;; FIXME, continued: Except that section "3.2.2.3 Semantic
+ ;; Constraints" says that if it's within the same file, it's
+ ;; wrong. And we're in locall.lisp here, so it's probably
+ ;; (haven't checked this..) a call to something in the same
+ ;; file. So maybe it deserves a full warning anyway.
(compiler-warning
"function called with ~R argument~:P, but wants exactly ~R"
call-args nargs)
\f
;;;; optional, more and keyword calls
-;;; Similar to Convert-Lambda-Call, but deals with Optional-Dispatches. If
-;;; only fixed args are supplied, then convert a call to the correct entry
-;;; point. If keyword args are supplied, then dispatch to a subfunction. We
-;;; don't convert calls to functions that have a more (or rest) arg.
+;;; This is similar to CONVERT-LAMBDA-CALL, but deals with
+;;; OPTIONAL-DISPATCHes. If only fixed args are supplied, then convert
+;;; a call to the correct entry point. If &KEY args are supplied, then
+;;; dispatch to a subfunction. We don't convert calls to functions
+;;; that have a &MORE (or &REST) arg.
(defun convert-hairy-call (ref call fun)
(declare (type ref ref) (type combination call)
(type optional-dispatch fun))
(max-args (optional-dispatch-max-args fun))
(call-args (length (combination-args call))))
(cond ((< call-args min-args)
- ;; FIXME: ANSI requires in "3.2.5 Exceptional Situations in the
- ;; Compiler" that calling a function with "the wrong number of
- ;; arguments" be only a STYLE-ERROR. I think, though, that this
- ;; should only apply when the number of arguments is inferred
- ;; from a previous definition. If the number of arguments
- ;; is DECLAIMed, surely calling with the wrong number is a
- ;; real WARNING. As long as SBCL continues to use CMU CL's
- ;; non-ANSI DEFUN-is-a-DECLAIM policy, we're in violation here,
- ;; but as long as we continue to use that policy, that's the
- ;; not our biggest problem.:-| When we fix that policy, this
- ;; should come back into compliance. (So fix that policy!)
+ ;; FIXME: See FIXME note at the previous
+ ;; wrong-number-of-arguments warnings in this file.
(compiler-warning
"function called with ~R argument~:P, but wants at least ~R"
call-args min-args)
((optional-dispatch-more-entry fun)
(convert-more-call ref call fun))
(t
- ;; FIXME: ANSI requires in "3.2.5 Exceptional Situations in the
- ;; Compiler" that calling a function with "the wrong number of
- ;; arguments" be only a STYLE-ERROR. I think, though, that this
- ;; should only apply when the number of arguments is inferred
- ;; from a previous definition. If the number of arguments
- ;; is DECLAIMed, surely calling with the wrong number is a
- ;; real WARNING. As long as SBCL continues to use CMU CL's
- ;; non-ANSI DEFUN-is-a-DECLAIM policy, we're in violation here,
- ;; but as long as we continue to use that policy, that's the
- ;; not our biggest problem.:-| When we fix that policy, this
- ;; should come back into compliance. (So fix that policy!)
+ ;; FIXME: See FIXME note at the previous
+ ;; wrong-number-of-arguments warnings in this file.
(compiler-warning
"function called with ~R argument~:P, but wants at most ~R"
call-args max-args)
(dolist (ref (leaf-refs entry))
(convert-call-if-possible ref (continuation-dest (node-cont ref))))))
-;;; Use Convert-Hairy-Fun-Entry to convert a more-arg call to a known
-;;; function into a local call to the Main-Entry.
+;;; Use CONVERT-HAIRY-FUN-ENTRY to convert a &MORE-arg call to a known
+;;; function into a local call to the MAIN-ENTRY.
;;;
;;; First we verify that all keywords are constant and legal. If there
;;; aren't, then we warn the user and don't attempt to convert the call.
;;;
-;;; We massage the supplied keyword arguments into the order expected by the
-;;; main entry. This is done by binding all the arguments to the keyword call
-;;; to variables in the introduced lambda, then passing these values variables
-;;; in the correct order when calling the main entry. Unused arguments
-;;; (such as the keywords themselves) are discarded simply by not passing them
-;;; along.
+;;; We massage the supplied &KEY arguments into the order expected
+;;; by the main entry. This is done by binding all the arguments to
+;;; the keyword call to variables in the introduced lambda, then
+;;; passing these values variables in the correct order when calling
+;;; the main entry. Unused arguments (such as the keywords themselves)
+;;; are discarded simply by not passing them along.
;;;
-;;; If there is a rest arg, then we bundle up the args and pass them to LIST.
+;;; If there is a &REST arg, then we bundle up the args and pass them
+;;; to LIST.
(defun convert-more-call (ref call fun)
(declare (type ref ref) (type combination call) (type optional-dispatch fun))
(let* ((max (optional-dispatch-max-args fun))
(arglist (optional-dispatch-arglist fun))
(args (combination-args call))
(more (nthcdr max args))
- (flame (policy call (or (> speed brevity) (> space brevity))))
+ (flame (policy call (or (> speed inhibit-warnings)
+ (> space inhibit-warnings))))
(loser nil)
(temps (make-gensym-list max))
(more-temps (make-gensym-list (length more))))
(ignores dummy val)
(setq loser name)))
(let ((info (lambda-var-arg-info var)))
- (when (eq (arg-info-keyword info) name)
+ (when (eq (arg-info-key info) name)
(ignores dummy)
(supplied (cons var val))
(return)))))))
\f
;;;; LET conversion
;;;;
-;;;; Converting to a LET has differing significance to various parts of the
-;;;; compiler:
-;;;; -- The body of a LET is spliced in immediately after the corresponding
-;;;; combination node, making the control transfer explicit and allowing
-;;;; LETs to be mashed together into a single block. The value of the LET is
-;;;; delivered directly to the original continuation for the call,
-;;;; eliminating the need to propagate information from the dummy result
-;;;; continuation.
-;;;; -- As far as IR1 optimization is concerned, it is interesting in that
-;;;; there is only one expression that the variable can be bound to, and
-;;;; this is easily substitited for.
-;;;; -- LETs are interesting to environment analysis and to the back end
-;;;; because in most ways a LET can be considered to be "the same function"
-;;;; as its home function.
-;;;; -- LET conversion has dynamic scope implications, since control transfers
-;;;; within the same environment are local. In a local control transfer,
-;;;; cleanup code must be emitted to remove dynamic bindings that are no
-;;;; longer in effect.
-
-;;; Set up the control transfer to the called lambda. We split the call
-;;; block immediately after the call, and link the head of FUN to the call
-;;; block. The successor block after splitting (where we return to) is
-;;; returned.
-;;;
-;;; If the lambda is is a different component than the call, then we call
-;;; JOIN-COMPONENTS. This only happens in block compilation before
-;;; FIND-INITIAL-DFO.
+;;;; Converting to a LET has differing significance to various parts
+;;;; of the compiler:
+;;;; -- The body of a LET is spliced in immediately after the
+;;;; corresponding combination node, making the control transfer
+;;;; explicit and allowing LETs to be mashed together into a single
+;;;; block. The value of the LET is delivered directly to the
+;;;; original continuation for the call,eliminating the need to
+;;;; propagate information from the dummy result continuation.
+;;;; -- As far as IR1 optimization is concerned, it is interesting in
+;;;; that there is only one expression that the variable can be bound
+;;;; to, and this is easily substitited for.
+;;;; -- LETs are interesting to environment analysis and to the back
+;;;; end because in most ways a LET can be considered to be "the
+;;;; same function" as its home function.
+;;;; -- LET conversion has dynamic scope implications, since control
+;;;; transfers within the same environment are local. In a local
+;;;; control transfer, cleanup code must be emitted to remove
+;;;; dynamic bindings that are no longer in effect.
+
+;;; Set up the control transfer to the called lambda. We split the
+;;; call block immediately after the call, and link the head of FUN to
+;;; the call block. The successor block after splitting (where we
+;;; return to) is returned.
+;;;
+;;; If the lambda is is a different component than the call, then we
+;;; call JOIN-COMPONENTS. This only happens in block compilation
+;;; before FIND-INITIAL-DFO.
(defun insert-let-body (fun call)
(declare (type clambda fun) (type basic-combination call))
(let* ((call-block (node-block call))
(component (block-component call-block)))
(let ((fun-component (block-component bind-block)))
(unless (eq fun-component component)
- (assert (eq (component-kind component) :initial))
+ (aver (eq (component-kind component) :initial))
(join-components component fun-component)))
(let ((*current-component* component))
;; FIXME: Use PROPER-LIST-OF-LENGTH-P here, and look for other
;; uses of '=.*length' which could also be converted to use
;; PROPER-LIST-OF-LENGTH-P.
- (assert (= (length (block-succ call-block)) 1))
+ (aver (= (length (block-succ call-block)) 1))
(let ((next-block (first (block-succ call-block))))
(unlink-blocks call-block next-block)
(link-blocks call-block bind-block)
next-block)))
-;;; Handle the environment semantics of LET conversion. We add the lambda
-;;; and its LETs to lets for the Call's home function. We merge the calls for
-;;; Fun with the calls for the home function, removing Fun in the process. We
-;;; also merge the Entries.
+;;; Handle the environment semantics of LET conversion. We add the
+;;; lambda and its LETs to lets for the CALL's home function. We merge
+;;; the calls for FUN with the calls for the home function, removing
+;;; FUN in the process. We also merge the Entries.
;;;
;;; We also unlink the function head from the component head and set
-;;; Component-Reanalyze to true to indicate that the DFO should be recomputed.
+;;; COMPONENT-REANALYZE to true to indicate that the DFO should be
+;;; recomputed.
(defun merge-lets (fun call)
(declare (type clambda fun) (type basic-combination call))
(let ((component (block-component (node-block call))))
(setf (lambda-lets fun) ()))
(setf (lambda-calls home)
- (nunion (lambda-calls fun)
- (delete fun (lambda-calls home))))
+ (delete fun (nunion (lambda-calls fun) (lambda-calls home))))
(setf (lambda-calls fun) ())
(setf (lambda-entries home)
(setf (lambda-entries fun) ()))
(values))
-;;; Handle the value semantics of let conversion. Delete Fun's return node,
-;;; and change the control flow to transfer to Next-Block instead. Move all
-;;; the uses of the result continuation to Call's Cont.
+;;; Handle the value semantics of LET conversion. Delete FUN's return
+;;; node, and change the control flow to transfer to NEXT-BLOCK
+;;; instead. Move all the uses of the result continuation to CALL's
+;;; CONT.
;;;
-;;; If the actual continuation is only used by the let call, then we
-;;; intersect the type assertion on the dummy continuation with the assertion
-;;; for the actual continuation; in all other cases assertions on the dummy
-;;; continuation are lost.
+;;; If the actual continuation is only used by the LET call, then we
+;;; intersect the type assertion on the dummy continuation with the
+;;; assertion for the actual continuation; in all other cases
+;;; assertions on the dummy continuation are lost.
;;;
-;;; We also intersect the derived type of the call with the derived type of
-;;; all the dummy continuation's uses. This serves mainly to propagate
-;;; TRULY-THE through lets.
+;;; We also intersect the derived type of the CALL with the derived
+;;; type of all the dummy continuation's uses. This serves mainly to
+;;; propagate TRULY-THE through LETs.
(defun move-return-uses (fun call next-block)
(declare (type clambda fun) (type basic-combination call)
(type cblock next-block))
(substitute-continuation-uses cont result)))
(values))
-;;; Change all Cont for all the calls to Fun to be the start continuation
-;;; for the bind node. This allows the blocks to be joined if the caller count
-;;; ever goes to one.
+;;; Change all CONT for all the calls to FUN to be the start
+;;; continuation for the bind node. This allows the blocks to be
+;;; joined if the caller count ever goes to one.
(defun move-let-call-cont (fun)
(declare (type clambda fun))
(let ((new-cont (node-prev (lambda-bind fun))))
(add-continuation-use dest new-cont))))
(values))
-;;; We are converting Fun to be a let when the call is in a non-tail
-;;; position. Any previously tail calls in Fun are no longer tail calls, and
-;;; must be restored to normal calls which transfer to Next-Block (Fun's
-;;; return point.) We can't do this by DO-USES on the RETURN-RESULT, because
-;;; the return might have been deleted (if all calls were TR.)
+;;; We are converting FUN to be a LET when the call is in a non-tail
+;;; position. Any previously tail calls in FUN are no longer tail
+;;; calls, and must be restored to normal calls which transfer to
+;;; NEXT-BLOCK (FUN's return point.) We can't do this by DO-USES on
+;;; the RETURN-RESULT, because the return might have been deleted (if
+;;; all calls were TR.)
;;;
-;;; The called function might be an assignment in the case where we are
-;;; currently converting that function. In steady-state, assignments never
-;;; appear in the lambda-calls.
+;;; The called function might be an assignment in the case where we
+;;; are currently converting that function. In steady-state,
+;;; assignments never appear in the lambda-calls.
(defun unconvert-tail-calls (fun call next-block)
(dolist (called (lambda-calls fun))
(dolist (ref (leaf-refs called))
(add-continuation-use this-call cont)))
(:deleted)
(:assignment
- (assert (eq called fun))))))))
+ (aver (eq called fun))))))))
(values))
-;;; Deal with returning from a let or assignment that we are converting.
-;;; FUN is the function we are calling, CALL is a call to FUN, and NEXT-BLOCK
-;;; is the return point for a non-tail call, or NULL if call is a tail call.
-;;;
-;;; If the call is not a tail call, then we must do UNCONVERT-TAIL-CALLS, since
-;;; a tail call is a call which returns its value out of the enclosing non-let
-;;; function. When call is non-TR, we must convert it back to an ordinary
-;;; local call, since the value must be delivered to the receiver of CALL's
-;;; value.
-;;;
-;;; We do different things depending on whether the caller and callee have
-;;; returns left:
-;;; -- If the callee has no return we just do MOVE-LET-CALL-CONT. Either the
-;;; function doesn't return, or all returns are via tail-recursive local
-;;; calls.
+;;; Deal with returning from a LET or assignment that we are
+;;; converting. FUN is the function we are calling, CALL is a call to
+;;; FUN, and NEXT-BLOCK is the return point for a non-tail call, or
+;;; NULL if call is a tail call.
+;;;
+;;; If the call is not a tail call, then we must do
+;;; UNCONVERT-TAIL-CALLS, since a tail call is a call which returns
+;;; its value out of the enclosing non-let function. When call is
+;;; non-TR, we must convert it back to an ordinary local call, since
+;;; the value must be delivered to the receiver of CALL's value.
+;;;
+;;; We do different things depending on whether the caller and callee
+;;; have returns left:
+
+;;; -- If the callee has no return we just do MOVE-LET-CALL-CONT. Either
+;;; the function doesn't return, or all returns are via tail-recursive
+;;; local calls.
;;; -- If CALL is a non-tail call, or if both have returns, then we
;;; delete the callee's return, move its uses to the call's result
;;; continuation, and transfer control to the appropriate return point.
(move-return-uses fun call
(or next-block (node-block call-return)))))
(t
- (assert (node-tail-p call))
+ (aver (node-tail-p call))
(setf (lambda-return call-fun) return)
(setf (return-lambda return) call-fun))))
(move-let-call-cont fun)
(values))
;;; Actually do LET conversion. We call subfunctions to do most of the
-;;; work. We change the CALL's cont to be the continuation heading the bind
-;;; block, and also do REOPTIMIZE-CONTINUATION on the args and Cont so that
-;;; let-specific IR1 optimizations get a chance. We blow away any entry for
-;;; the function in *FREE-FUNCTIONS* so that nobody will create new reference
-;;; to it.
+;;; work. We change the CALL's cont to be the continuation heading the
+;;; bind block, and also do REOPTIMIZE-CONTINUATION on the args and
+;;; Cont so that let-specific IR1 optimizations get a chance. We blow
+;;; away any entry for the function in *FREE-FUNCTIONS* so that nobody
+;;; will create new reference to it.
(defun let-convert (fun call)
(declare (type clambda fun) (type basic-combination call))
(let ((next-block (if (node-tail-p call)
(reoptimize-continuation (node-cont call))
(values))
-;;; We also don't convert calls to named functions which appear in the initial
-;;; component, delaying this until optimization. This minimizes the likelyhood
-;;; that we well let-convert a function which may have references added due to
-;;; later local inline expansion
+;;; We also don't convert calls to named functions which appear in the
+;;; initial component, delaying this until optimization. This
+;;; minimizes the likelyhood that we well let-convert a function which
+;;; may have references added due to later local inline expansion
(defun ok-initial-convert-p (fun)
(not (and (leaf-name fun)
(eq (component-kind
:initial))))
;;; This function is called when there is some reason to believe that
-;;; the lambda Fun might be converted into a let. This is done after local
-;;; call analysis, and also when a reference is deleted. We only convert to a
-;;; let when the function is a normal local function, has no XEP, and is
-;;; referenced in exactly one local call. Conversion is also inhibited if the
-;;; only reference is in a block about to be deleted. We return true if we
-;;; converted.
-;;;
-;;; These rules may seem unnecessarily restrictive, since there are some
-;;; cases where we could do the return with a jump that don't satisfy these
-;;; requirements. The reason for doing things this way is that it makes the
-;;; concept of a let much more useful at the level of IR1 semantics. The
-;;; :ASSIGNMENT function kind provides another way to optimize calls to
-;;; single-return/multiple call functions.
-;;;
-;;; We don't attempt to convert calls to functions that have an XEP, since
-;;; we might be embarrassed later when we want to convert a newly discovered
-;;; local call. Also, see OK-INITIAL-CONVERT-P.
+;;; the lambda Fun might be converted into a let. This is done after
+;;; local call analysis, and also when a reference is deleted. We only
+;;; convert to a let when the function is a normal local function, has
+;;; no XEP, and is referenced in exactly one local call. Conversion is
+;;; also inhibited if the only reference is in a block about to be
+;;; deleted. We return true if we converted.
+;;;
+;;; These rules may seem unnecessarily restrictive, since there are
+;;; some cases where we could do the return with a jump that don't
+;;; satisfy these requirements. The reason for doing things this way
+;;; is that it makes the concept of a LET much more useful at the
+;;; level of IR1 semantics. The :ASSIGNMENT function kind provides
+;;; another way to optimize calls to single-return/multiple call
+;;; functions.
+;;;
+;;; We don't attempt to convert calls to functions that have an XEP,
+;;; since we might be embarrassed later when we want to convert a
+;;; newly discovered local call. Also, see OK-INITIAL-CONVERT-P.
(defun maybe-let-convert (fun)
(declare (type clambda fun))
(let ((refs (leaf-refs fun)))
\f
;;;; tail local calls and assignments
-;;; Return T if there are no cleanups between Block1 and Block2, or if they
-;;; definitely won't generate any cleanup code. Currently we recognize lexical
-;;; entry points that are only used locally (if at all).
+;;; Return T if there are no cleanups between BLOCK1 and BLOCK2, or if
+;;; they definitely won't generate any cleanup code. Currently we
+;;; recognize lexical entry points that are only used locally (if at
+;;; all).
(defun only-harmless-cleanups (block1 block2)
(declare (type cblock block1 block2))
(or (eq block1 block2)
(return nil)))
(t (return nil)))))))
-;;; If a potentially TR local call really is TR, then convert it to jump
-;;; directly to the called function. We also call MAYBE-CONVERT-TO-ASSIGNMENT.
-;;; The first value is true if we tail-convert. The second is the value of
-;;; M-C-T-A. We can switch the succesor (potentially deleting the RETURN node)
-;;; unless:
+;;; If a potentially TR local call really is TR, then convert it to
+;;; jump directly to the called function. We also call
+;;; MAYBE-CONVERT-TO-ASSIGNMENT. The first value is true if we
+;;; tail-convert. The second is the value of M-C-T-A. We can switch
+;;; the succesor (potentially deleting the RETURN node) unless:
;;; -- The call has already been converted.
;;; -- The call isn't TR (some implicit MV PROG1.)
-;;; -- The call is in an XEP (thus we might decide to make it non-tail so that
-;;; we can use known return inside the component.)
-;;; -- There is a change in the cleanup between the call in the return, so we
-;;; might need to introduce cleanup code.
+;;; -- The call is in an XEP (thus we might decide to make it non-tail
+;;; so that we can use known return inside the component.)
+;;; -- There is a change in the cleanup between the call in the return,
+;;; so we might need to introduce cleanup code.
(defun maybe-convert-tail-local-call (call)
(declare (type combination call))
(let ((return (continuation-dest (node-cont call))))
- (assert (return-p return))
+ (aver (return-p return))
(when (and (not (node-tail-p call))
(immediately-used-p (return-result return) call)
(not (eq (functional-kind (node-home-lambda call))
(link-blocks block (node-block (lambda-bind fun)))
(values t (maybe-convert-to-assignment fun))))))
-;;; Called when we believe it might make sense to convert Fun to an
-;;; assignment. All this function really does is determine when a function
-;;; with more than one call can still be combined with the calling function's
-;;; environment. We can convert when:
+;;; This is called when we believe it might make sense to convert Fun
+;;; to an assignment. All this function really does is determine when
+;;; a function with more than one call can still be combined with the
+;;; calling function's environment. We can convert when:
;;; -- The function is a normal, non-entry function, and
-;;; -- Except for one call, all calls must be tail recursive calls in the
-;;; called function (i.e. are self-recursive tail calls)
+;;; -- Except for one call, all calls must be tail recursive calls
+;;; in the called function (i.e. are self-recursive tail calls)
;;; -- OK-INITIAL-CONVERT-P is true.
;;;
-;;; There may be one outside call, and it need not be tail-recursive. Since
-;;; all tail local calls have already been converted to direct transfers, the
-;;; only control semantics needed are to splice in the body at the non-tail
-;;; call. If there is no non-tail call, then we need only merge the
-;;; environments. Both cases are handled by LET-CONVERT.
-;;;
-;;; ### It would actually be possible to allow any number of outside calls as
-;;; long as they all return to the same place (i.e. have the same conceptual
-;;; continuation.) A special case of this would be when all of the outside
-;;; calls are tail recursive.
+;;; There may be one outside call, and it need not be tail-recursive.
+;;; Since all tail local calls have already been converted to direct
+;;; transfers, the only control semantics needed are to splice in the
+;;; body at the non-tail call. If there is no non-tail call, then we
+;;; need only merge the environments. Both cases are handled by
+;;; LET-CONVERT.
+;;;
+;;; ### It would actually be possible to allow any number of outside
+;;; calls as long as they all return to the same place (i.e. have the
+;;; same conceptual continuation.) A special case of this would be
+;;; when all of the outside calls are tail recursive.
(defun maybe-convert-to-assignment (fun)
(declare (type clambda fun))
(when (and (not (functional-kind fun))
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