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;;; -*- Package: C; Log: C.Log -*-
;;;
;;; **********************************************************************
;;; This code was written as part of the Spice Lisp project at
;;; Carnegie-Mellon University, and has been placed in the public domain.
;;; If you want to use this code or any part of Spice Lisp, please contact
;;; Scott Fahlman (FAHLMAN@CMUC).
;;; **********************************************************************
;;;
;;; This file contains random utilities used for manipulating the IR1
;;; representation.
;;;
;;; Written by Rob MacLachlan
;;;
(in-package 'c)
;;;; Cleanup hackery:
;;; Find-Enclosing-Cleanup -- Interface
;;;
;;; Chain up the Lambda-Cleanup thread until we find a Cleanup or null.
;;;
(defun find-enclosing-cleanup (thing)
(declare (type (or cleanup clambda null) thing))
(etypecase thing
((or cleanup null) thing)
(clambda (find-enclosing-cleanup (lambda-cleanup thing)))))
;;; Insert-Cleanup-Code -- Interface
;;;
;;; Convert the Form in a block inserted between Block1 and Block2 as an
;;; implicit MV-Prog1. The inserted block is returned. Node is used for IR1
;;; context when converting the form. Note that the block is not assigned a
;;; number, and is linked into the DFO at the beginning. We indicate that we
;;; have trashed the DFO by setting Component-Reanalyze.
;;;
(defun insert-cleanup-code (block1 block2 node form)
(declare (type cblock block1 block2) (type node node))
(with-ir1-environment node
(setf (component-reanalyze *current-component*) t)
(let* ((start (make-continuation))
(block (continuation-starts-block start))
(cont (make-continuation)))
(change-block-successor block1 block2 block)
(link-blocks block block2)
(ir1-convert start cont form)
(setf (block-last block) (continuation-use cont))
block)))
;;;; Continuation use hacking:
;;; Find-Uses -- Interface
;;;
;;; Return a list of all the nodes which use Cont.
;;;
(proclaim '(function find-uses (continuation) list))
(defun find-uses (cont)
(ecase (continuation-kind cont)
((:block-start :deleted-block-start)
(block-start-uses (continuation-block cont)))
(:inside-block (list (continuation-use cont)))
(:unused nil)))
;;; Delete-Continuation-Use -- Interface
;;;
;;; Update continuation use information so that Node is no longer a use of
;;; its Cont. If the old continuation doesn't start its block, then we don't
;;; update the Block-Start-Uses, since it will be deleted when we are done.
;;;
;;; Note: if you call this function, you may have to do a
;;; REOPTIMIZE-CONTINUATION to inform IR1 optimization that something has
;;; changed.
;;;
(proclaim '(function delete-continuation-use (node) void))
(defun delete-continuation-use (node)
(let* ((cont (node-cont node))
(block (continuation-block cont)))
(ecase (continuation-kind cont)
(:deleted)
((:block-start :deleted-block-start)
(let ((uses (delete node (block-start-uses block))))
(setf (block-start-uses block) uses)
(setf (continuation-use cont)
(if (cdr uses) nil (car uses)))))
(:inside-block
(setf (continuation-kind cont) :unused)
(setf (continuation-block cont) nil)
(setf (continuation-use cont) nil)
(setf (continuation-next cont) nil)))
(setf (node-cont node) nil)))
;;; Add-Continuation-Use -- Interface
;;;
;;; Update continuation use information so that Node uses Cont. If Cont is
;;; :Unused, then we set its block to Node's Node-Block (which must be set.)
;;;
;;; Note: if you call this function, you may have to do a
;;; REOPTIMIZE-CONTINUATION to inform IR1 optimization that something has
;;; changed.
;;;
(proclaim '(function add-continuation-use (node continuation) void))
(defun add-continuation-use (node cont)
(assert (not (node-cont node)))
(let ((block (continuation-block cont)))
(ecase (continuation-kind cont)
(:deleted)
(:unused
(assert (not block))
(let ((block (node-block node)))
(assert block)
(setf (continuation-block cont) block))
(setf (continuation-kind cont) :inside-block)
(setf (continuation-use cont) node))
((:block-start :deleted-block-start)
(let ((uses (cons node (block-start-uses block))))
(setf (block-start-uses block) uses)
(setf (continuation-use cont)
(if (cdr uses) nil (car uses)))))))
(setf (node-cont node) cont))
;;; Immediately-Used-P -- Interface
;;;
;;; Return true if Cont is the Node-Cont for Node and Cont is transferred to
;;; immediately after the evaluation of Node.
;;;
(defun immediately-used-p (cont node)
(declare (type continuation cont) (type node node))
(and (eq (node-cont node) cont)
(not (eq (continuation-kind cont) :deleted))
(let ((cblock (continuation-block cont))
(nblock (node-block node)))
(or (eq cblock nblock)
(let ((succ (block-succ nblock)))
(and (= (length succ) 1)
(eq (first succ) cblock)))))))
;;;; Continuation substitution:
;;; Substitute-Continuation -- Interface
;;;
;;; In Old's Dest, replace Old with New. New's Dest must initially be NIL.
;;; When we are done, we call Flush-Dest on Old to clear its Dest and to note
;;; potential optimization opportunities.
;;;
(defun substitute-continuation (new old)
(declare (type continuation old new))
(assert (not (continuation-dest new)))
(let ((dest (continuation-dest old)))
(etypecase dest
((or ref bind))
(cif (setf (if-test dest) new))
(cset (setf (set-value dest) new))
(creturn (setf (return-result dest) new))
(exit (setf (exit-value dest) new))
(basic-combination
(if (eq old (basic-combination-fun dest))
(setf (basic-combination-fun dest) new)
(setf (basic-combination-args dest)
(nsubst new old (basic-combination-args dest))))))
(flush-dest old)
(setf (continuation-dest new) dest))
(undefined-value))
;;; Ensure-Block-Start -- Interface
;;;
;;; Ensure that Cont is the start of a block (or deleted) so that the use
;;; set can be freely manipulated.
;;; -- If the continuation is :Unused or is :Inside-Block and the Cont of Last
;;; in its block, then we make it the start of a new deleted block.
;;; -- If the continuation is :Inside-Block inside a block, then we split the
;;; block using Node-Ends-Block, which makes the continuation be a
;;; :Block-Start.
;;;
(defun ensure-block-start (cont)
(declare (type continuation cont))
(let ((kind (continuation-kind cont)))
(ecase kind
((:deleted :block-start :deleted-block-start))
((:unused :inside-block)
(let ((block (continuation-block cont)))
(cond ((or (eq kind :unused)
(eq (node-cont (block-last block)) cont))
(setf (continuation-block cont)
(make-block-key :start cont :lambda nil
:start-cleanup nil :end-cleanup nil
:component nil))
(setf (continuation-kind cont) :deleted-block-start))
(t
(node-ends-block (continuation-use cont))))))))
(undefined-value))
;;; Substitute-Continuation-Uses -- Interface
;;;
;;; Replace all uses of Old with uses of New, where New has an arbitary
;;; number of uses. If a use is an Exit, then we also substitute New for Old
;;; in the Entry's Exits to maintain consistency between the two.
;;;
;;; If New will end up with more than one use, then we must arrange for it
;;; to start a block if it doesn't already.
;;;
(defun substitute-continuation-uses (new old)
(declare (type continuation old new))
(unless (and (eq (continuation-kind new) :unused)
(eq (continuation-kind old) :inside-block))
(ensure-block-start new))
(do-uses (node old)
(when (exit-p node)
(let ((entry (exit-entry node)))
(when entry
(setf (entry-exits entry)
(nsubst new old (entry-exits entry))))))
(delete-continuation-use node)
(add-continuation-use node new))
(reoptimize-continuation new)
(undefined-value))
#|
;;; Substitute-Node-Cont -- Interface
;;;
;;; Replace Old's single use with a use of New. This is used in contexts
;;; where we know that New has no use and Old has a single use.
;;;
(defun substitute-node-cont (new old)
(declare (type continuation new old))
(assert (member (continuation-kind new) '(:block-start :unused)))
(assert (eq (continuation-kind old) :inside-block))
(let ((use (continuation-use old)))
(delete-continuation-use use)
(add-continuation-use use new))
(undefined-value))
|#
;;; NODE-BLOCK, NODE-ENVIRONMENT, NODE-TLF-NUMBER -- Interface
(proclaim '(inline node-block node-environment node-tlf-number))
(defun node-block (node)
(declare (type node node))
(the cblock (continuation-block (node-prev node))))
;;;
(defun node-environment (node)
(declare (type node node))
(the environment (lambda-environment (block-lambda (node-block node)))))
;;;
(defun node-tlf-number (node)
(declare (type node node))
(car (last (node-source-path node))))
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;;;; Flow/DFO/Component hackery:
;;; Link-Blocks, Unlink-Blocks -- Interface
;;;
;;; Join or separate Block1 and Block2.
;;;
(proclaim '(ftype (function (block block) void) link-blocks unlink-blocks))
(defun link-blocks (block1 block2)
(assert (not (member block2 (block-succ block1))))
(push block2 (block-succ block1))
(push block1 (block-pred block2)))
;;;
(defun unlink-blocks (block1 block2)
(assert (member block2 (block-succ block1)))
(setf (block-succ block1)
(delete block2 (block-succ block1)))
(setf (block-pred block2)
(delete block1 (block-pred block2))))
;;; Change-Block-Successor -- Internal
;;;
;;; Swing the succ/pred link between Block and Old to be between Block and
;;; New. If Block ends in an IF, then we have to fix up the
;;; consequent/alternative blocks to point to New.
;;;
(defun change-block-successor (block old new)
(declare (type cblock new old block))
(unlink-blocks block old)
(unless (member new (block-succ block))
(link-blocks block new))
(let ((last (block-last block)))
(when (if-p last)
(macrolet ((frob (slot)
`(when (eq (,slot last) old)
(setf (,slot last) new))))
(frob if-consequent)
(frob if-alternative))))
(undefined-value))
;;; Remove-From-DFO -- Interface
;;;
;;; Unlink a block from the next/prev chain. We also null out the
;;; Component.
;;;
(proclaim '(function remove-from-dfo (cblock) void))
(defun remove-from-dfo (block)
(let ((next (block-next block))
(prev (block-prev block)))
(setf (block-component block) nil)
(setf (block-next prev) next)
(setf (block-prev next) prev)))
;;; Add-To-DFO -- Interface
;;;
;;; Add Block to the next/prev chain following After. We also set the
;;; Component to be the same as for After.
;;;
(proclaim '(function add-to-dfo (block block) void))
(defun add-to-dfo (block after)
(let ((next (block-next after)))
(setf (block-component block) (block-component after))
(setf (block-next after) block)
(setf (block-prev block) after)
(setf (block-next block) next)
(setf (block-prev next) block)))
;;; Clear-Flags -- Interface
;;;
;;; Set the Flag for all the blocks in Component to NIL, except for the head
;;; and tail which are set to T.
;;;
(proclaim '(function clear-flags (component) void))
(defun clear-flags (component)
(let ((head (component-head component))
(tail (component-tail component)))
(setf (block-flag head) t)
(setf (block-flag tail) t)
(do-blocks (block component)
(setf (block-flag block) nil))))
;;; Make-Empty-Component -- Interface
;;;
;;; Make a component with no blocks in it. The Block-Flag is initially true
;;; in the head and tail blocks.
;;;
(proclaim '(function make-empty-component () component))
(defun make-empty-component ()
(let* ((head (make-block-key :start nil :lambda nil :start-cleanup nil
:end-cleanup nil :component nil))
(tail (make-block-key :start nil :lambda nil :start-cleanup nil
:end-cleanup nil :component nil))
(res (make-component :head head :tail tail)))
(setf (block-flag head) t)
(setf (block-flag tail) t)
(setf (block-component head) res)
(setf (block-component tail) res)
(setf (block-next head) tail)
(setf (block-prev tail) head)
res))
;;; Node-Ends-Block -- Interface
;;;
;;; Makes Node the Last node in its block, splitting the block if necessary.
;;;
;;; If the mess-up for one of Block's End-Cleanups is moved into the new
;;; block, then we must adjust the end/start cleanups of the new and old blocks
;;; to reflect the movement of the mess-up. If any of the old end cleanups
;;; were in the new block, then we scan up from that cleanup trying to find one
;;; that isn't. When we do, that becomes the new start/end cleanup of the
;;; old/new block. We set the start/end as a pair, since we don't want anyone
;;; to think that a cleanup is necessary.
;;;
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(defun node-ends-block (node)
(declare (type node node))
(let* ((block (node-block node))
(start (node-cont node))
(last (block-last block))
(last-cont (node-cont last)))
(unless (eq last node)
(assert (eq (continuation-kind start) :inside-block))
(let* ((succ (block-succ block))
(cleanup (block-end-cleanup block))
(new-block
(make-block-key :start start
:lambda (block-lambda block)
:start-cleanup cleanup
:end-cleanup cleanup
:component (block-component block)
:start-uses (list (continuation-use start))
:succ succ :last last)))
(setf (continuation-kind start) :block-start)
(dolist (b succ)
(setf (block-pred b)
(cons new-block (remove block (block-pred b)))))
(setf (block-succ block) ())
(setf (block-last block) node)
(link-blocks block new-block)
(add-to-dfo new-block block)
(do ((cont start (node-cont (continuation-next cont))))
((eq cont last-cont)
(when (eq (continuation-kind last-cont) :inside-block)
(setf (continuation-block last-cont) new-block)))
(setf (continuation-block cont) new-block))
(let ((start-cleanup (block-start-cleanup block)))
(do ((cup (find-enclosing-cleanup cleanup)
(find-enclosing-cleanup (cleanup-enclosing cup))))
((null cup))
(when (eq (node-block (continuation-use (cleanup-start cup)))
new-block)
(do ((cup (find-enclosing-cleanup (cleanup-enclosing cup))
(find-enclosing-cleanup (cleanup-enclosing cup))))
((null cup)
(setf (block-end-cleanup block) start-cleanup)
(setf (block-start-cleanup new-block) start-cleanup))
(let ((cb (node-block (continuation-use (cleanup-start cup)))))
(unless (eq cb new-block)
(setf (block-end-cleanup block) cup)
(setf (block-start-cleanup new-block) cup)
(return))))
(return))))
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(setf (block-type-asserted block) t)
(setf (block-test-modified block) t))))
(undefined-value))
;;;; Deleting stuff:
;;; Delete-Lambda-Var -- Internal
;;;
;;; Deal with deleting the last (read) reference to a lambda-var. We
;;; iterate over all local calls flushing the corresponding argument, allowing
;;; the computation of the argument to be deleted.
;;;
;;; The lambda-var may still have some sets, but this doesn't cause too much
;;; difficulty, since we can efficiently implement write-only variables. We
;;; iterate over the sets, marking their blocks for dead code flushing, since
;;; we can delete sets whose value is unused.
;;;
(defun delete-lambda-var (leaf)
(declare (type lambda-var leaf))
(let* ((fun (lambda-var-home leaf))
(n (position leaf (lambda-vars fun))))
(dolist (ref (leaf-refs fun))
(let* ((cont (node-cont ref))
(dest (continuation-dest cont)))
(when (and (combination-p dest)
(eq (basic-combination-fun dest) cont)
(eq (basic-combination-kind dest) :local))
(let ((args (basic-combination-args dest)))
(flush-dest (elt args n))
(setf (elt args n) nil))))))
(dolist (set (lambda-var-sets leaf))
(setf (block-flush-p (node-block set)) t))
(undefined-value))
;;; Delete-Lambda -- Internal
;;;
;;; Deal with deleting the last reference to a lambda. Since there is only
;;; one way into a lambda, deleting the last reference to a lambda ensures that
;;; there is no way to reach any of the code in it. So we just set the
;;; Functional-Kind for Fun and its Lets to :Deleted, causing IR1 optimization
;;; to delete blocks in that lambda.
;;;
;;; If the function isn't a Let, we unlink the function head and tail from
;;; the component head and tail to indicate that the code is unreachable. We
;;; also delete the function Component-Lambdas (it won't be there before local
;;; call analysis, but no matter.)
;;;
;;; If the lambda is an XEP, then we null out the Entry-Function in its
;;; Entry-Function so that people will know that it is not an entry point
;;; anymore.
;;;
(defun delete-lambda (leaf)
(declare (type clambda leaf))
(let ((kind (functional-kind leaf)))
(assert (not (member kind '(:deleted :optional :top-level))))
(setf (functional-kind leaf) :deleted)
(dolist (let (lambda-lets leaf))
(setf (functional-kind let) :deleted))
(if (or (eq kind :let) (eq kind :mv-let))
(let ((home (lambda-home leaf)))
(setf (lambda-lets home) (delete leaf (lambda-lets home))))
(let* ((bind-block (node-block (lambda-bind leaf)))
(component (block-component bind-block))
(return (lambda-return leaf)))
(unlink-blocks (component-head component) bind-block)
(when return
(unlink-blocks (node-block return) (component-tail component)))
(setf (component-lambdas component)
(delete leaf (component-lambdas component)))))
(when (eq kind :external)
(let ((fun (functional-entry-function leaf)))
(setf (functional-entry-function fun) nil)
(when (optional-dispatch-p fun)
(delete-optional-dispatch fun)))))
(undefined-value))
;;; Delete-Optional-Dispatch -- Internal
;;;
;;; Deal with deleting the last reference to an Optional-Dispatch. We have
;;; to be a bit more careful than with lambdas, since Delete-Ref is used both
;;; before and after local call analysis. Afterward, all references to
;;; still-existing optional-dispatches have been moved to the XEP, leaving it
;;; with no references at all. So we look at the XEP to see if an
;;; optional-dispatch is still really being used. But before local call
;;; analysis, there are no XEPs, and all references are direct.
;;;
;;; When we do delete the optional-dispatch, we grovel all of its
;;; entry-points, making them be normal lambdas, and then deleting the ones
;;; with no references. This deletes any e-p lambdas that were either never
;;; referenced, or couldn't be deleted when the last deference was deleted (due
;;; to their :Optional kind.)
;;;
;;; Note that the last optional ep may alias the main entry, so when we process
;;; the main entry, its kind may have been changed to NIL or even converted to
;;; a let.
;;;
(defun delete-optional-dispatch (leaf)
(declare (type optional-dispatch leaf))
(let ((entry (functional-entry-function leaf)))
(unless (and entry (leaf-refs entry))
(assert (or (not entry) (eq (functional-kind entry) :deleted)))
(setf (functional-kind leaf) :deleted)
(flet ((frob (fun)
(unless (eq (functional-kind fun) :deleted)
(assert (eq (functional-kind fun) :optional))
(setf (functional-kind fun) nil)
(let ((refs (leaf-refs fun)))
(cond ((null refs)
(delete-lambda fun))
((null (rest refs))
(maybe-let-convert fun)))))))
(dolist (ep (optional-dispatch-entry-points leaf))
(frob ep))
(when (optional-dispatch-more-entry leaf)
(frob (optional-dispatch-more-entry leaf)))
(let ((main (optional-dispatch-main-entry leaf)))
(when (eq (functional-kind main) :optional)
(frob main))))))
(undefined-value))
;;; Delete-Ref -- Interface
;;;
;;; Do stuff to delete the semantic attachments of a Ref node. When this
;;; leaves zero or one reference, we do a type dispatch off of the leaf to
;;; determine if a special action is appropriate.
;;;
(defun delete-ref (ref)
(declare (type ref ref))
(let* ((leaf (ref-leaf ref))
(refs (delete ref (leaf-refs leaf))))
(setf (leaf-refs leaf) refs)
(cond ((null refs)
(typecase leaf
(lambda-var (delete-lambda-var leaf))
(clambda
(ecase (functional-kind leaf)
((nil :external :let :mv-let :escape :cleanup)
(delete-lambda leaf))
((:deleted :optional))))
(optional-dispatch
(unless (eq (functional-kind leaf) :deleted)
(delete-optional-dispatch leaf)))))
((null (rest refs))
(typecase leaf
(clambda (maybe-let-convert leaf))))))
(undefined-value))
;;; Delete-Return -- Interface
;;;
;;; Do stuff to indicate that the return node Node is being deleted.
;;;
(defun delete-return (node)
(declare (type creturn node))
(let* ((fun (return-lambda node))
(tail-set (lambda-tail-set fun)))
(assert (lambda-return fun))
(setf (tail-set-functions tail-set)
(delete fun (tail-set-functions tail-set)))
(setf (lambda-tail-set fun) nil)
(setf (lambda-return fun) nil))
(undefined-value))
;;; Flush-Dest -- Interface
;;;
;;; This function is called by people who delete nodes; it provides a way to
;;; indicate that the value of a continuation is no longer used. We null out
;;; the Continuation-Dest, set Block-Flush-P in the blocks containing uses of
;;; Cont and set Component-Reoptimize.
;;;
;;; If the continuation is :Deleted, then we don't do anything, since all
;;; semantics have already been flushed. If the continuation is a
;;; :Deleted-Block-Start, then we delete the continuation, since its control
;;; semantics have already been deleted. Deleting the continuation causes its
;;; uses to be reoptimized. If the Prev of the use is deleted, then we blow
;;; off reoptimization.
;;;
(defun flush-dest (cont)
(declare (type continuation cont))
(ecase (continuation-kind cont)
(:deleted)
(:deleted-block-start
(assert (continuation-dest cont))
(setf (continuation-dest cont) nil)
(delete-continuation cont))
((:inside-block :block-start)
(assert (continuation-dest cont))
(setf (continuation-dest cont) nil)
(setf (component-reoptimize (block-component (continuation-block cont)))
t)
(do-uses (use cont)
(let ((prev (node-prev use)))
(unless (eq (continuation-kind prev) :deleted)
(let ((block (continuation-block prev)))
(setf (block-flush-p block) t)
(setf (block-type-asserted block) t)))))))
(setf (continuation-%type-check cont) nil)
(undefined-value))
;;; MARK-FOR-DELETION -- Internal
;;;
;;; Do a graph walk backward from Block, marking all predecessor blocks with
;;; the DELETE-P flag.
;;;
(defun mark-for-deletion (block)
(declare (type cblock block))
(unless (block-delete-p block)
(setf (block-delete-p block) t)
(dolist (pred (block-pred block))
(mark-for-deletion pred)))
(undefined-value))
;;; DELETE-CONTINUATION -- Interface
;;;
;;; Delete Cont, eliminating both control and value semantics. We set
;;; FLUSH-P and COMPONENT-REOPTIMIZE similarly to in FLUSH-DEST. Here we must
;;; get the component from the use block, since the continuation may be a
;;; :DELETED-BLOCK-START.
;;;
;;; If Cont has DEST, then it must be the case that the DEST is unreachable,
;;; since we can't compute the value desired. In this case, we call
;;; MARK-FOR-DELETION to cause the DEST block and its predecessors to tell
;;; people to ignore them, and to cause them to be deleted eventually.
;;;
(defun delete-continuation (cont)
(declare (type continuation cont))
(assert (not (eq (continuation-kind cont) :deleted)))
(do-uses (use cont)
(let ((prev (node-prev use)))
(unless (eq (continuation-kind prev) :deleted)
(let ((block (continuation-block prev)))
(setf (block-flush-p block) t)
(setf (block-type-asserted block) t)
(setf (component-reoptimize (block-component block)) t)))))
(let ((dest (continuation-dest cont)))
(when dest
(let ((block (node-block dest)))
(unless (block-delete-p block)
(mark-for-deletion block)))))
(setf (continuation-kind cont) :deleted)
(setf (continuation-dest cont) nil)
(setf (continuation-next cont) nil)
(setf (continuation-asserted-type cont) *empty-type*)
(setf (continuation-%derived-type cont) *empty-type*)
(setf (continuation-use cont) nil)
(setf (continuation-block cont) nil)
(setf (continuation-reoptimize cont) nil)
(setf (continuation-%type-check cont) nil)
(setf (continuation-info cont) nil)
(undefined-value))
;;; Delete-Block -- Interface
;;;
;;; This function does what is necessary to eliminate the code in it from
;;; the IR1 representation. This involves unlinking it from its predecessors
;;; and successors and deleting various node-specific semantic information.
;;;
;;; We mark the Start as has having no next and remove the last node from
;;; its Cont's uses. We also flush the DEST for all continuations whose values
;;; are received by nodes in the block.
;;;
(defun delete-block (block)
(declare (type cblock block))
(assert (block-component block) () "Block is already deleted.")
(setf (block-delete-p block) t)
(let* ((last (block-last block))
(cont (node-cont last)))
(delete-continuation-use last)
(cond ((eq (continuation-kind cont) :unused)
(assert (not (continuation-dest cont)))
(delete-continuation cont))
(t
(reoptimize-continuation cont))))
(dolist (b (block-pred block))
(unlink-blocks b block))
(dolist (b (block-succ block))
(unlink-blocks block b))
(do-nodes (node cont block)
(typecase node
(ref (delete-ref node))
(basic-combination
(flush-dest (basic-combination-fun node))
(dolist (arg (basic-combination-args node))
(when arg (flush-dest arg))))
(cif
(flush-dest (if-test node)))
(bind
(let ((lambda (bind-lambda node)))
(unless (eq (functional-kind lambda) :deleted)
(assert (member (functional-kind lambda) '(:let :mv-let)))
(delete-lambda lambda))))
(exit
(let ((value (exit-value node)))
(when value
(flush-dest value))))
(creturn
(flush-dest (return-result node))
(delete-return node))
(cset
(flush-dest (set-value node))
(let ((var (set-var node)))
(setf (basic-var-sets var)
(delete node (basic-var-sets var))))))
(delete-continuation (node-prev node)))
(remove-from-dfo block)
(undefined-value))
;;; Unlink-Node -- Interface
;;;
;;; Delete a node from a block, deleting the block if there are no nodes
;;; left. We remove the node from the uses of its CONT, but we don't deal with
;;; cleaning up any type-specific semantic attachments. If the CONT is :UNUSED
;;; after deleting this use, then we delete CONT. (Note :UNUSED is not the
;;; same as no uses. A continuation will only become :UNUSED if it was
;;; :INSIDE-BLOCK before.)
;;;
;;; If the node is the last node, there must be exactly one successor. We
;;; link all of our precedessors to the successor and unlink the block. In
;;; this case, we return T, otherwise NIL. If no nodes are left, and the block
;;; is a successor of itself, then we replace the only node with a degenerate
;;; exit node. This provides a way to represent the bodyless infinite loop,
;;; given the prohibition on empty blocks in IR1.
;;;
(defun unlink-node (node)
(declare (type node node))
(let* ((cont (node-cont node))
(next (continuation-next cont))
(prev (node-prev node))
(block (continuation-block prev))
(prev-kind (continuation-kind prev))
(last (block-last block)))
(unless (eq (continuation-kind cont) :deleted)
(delete-continuation-use node)
(when (eq (continuation-kind cont) :unused)
(assert (not (continuation-dest cont)))
(delete-continuation cont)))
(setf (block-type-asserted block) t)
(setf (block-test-modified block) t)
(cond ((or (eq prev-kind :inside-block)
(and (eq prev-kind :block-start)
(not (eq node last))))
(cond ((eq node last)
(setf (block-last block) (continuation-use prev))
(setf (continuation-next prev) nil))
(t
(setf (continuation-next prev) next)
(setf (node-prev next) prev)))
(setf (node-prev node) nil)
nil)
(t
(assert (eq prev-kind :block-start))
(assert (eq node last))
(let* ((succ (block-succ block))
(next (first succ)))
(assert (and succ (null (cdr succ))))
(cond
((member block succ)
(with-ir1-environment node
(let ((exit (make-exit :source (node-source node)))
(dummy (make-continuation)))
(setf (continuation-next prev) nil)
(prev-link exit prev)
(add-continuation-use exit dummy)
(setf (block-last block) exit)))
(setf (node-prev node) nil)
nil)
(t
(assert (eq (find-enclosing-cleanup (block-start-cleanup block))
(find-enclosing-cleanup (block-end-cleanup block))))
(unlink-blocks block next)
(dolist (pred (block-pred block))
(change-block-successor pred block next))
(remove-from-dfo block)
(cond ((continuation-dest prev)
(setf (continuation-next prev) nil)
(setf (continuation-kind prev) :deleted-block-start))
(t
(delete-continuation prev)))
(setf (node-prev node) nil)
t)))))))
;;; NODE-DELETED -- Interface
;;;
;;; Return true if NODE has been deleted, false if it is still a valid part
;;; of IR1.
;;;
(defun node-deleted (node)
(declare (type node node))
(let ((prev (node-prev node)))
(and prev
(not (eq (continuation-kind prev) :deleted))
(let ((block (continuation-block prev)))
(and (block-component block)
(not (block-delete-p block)))))))
;;;; Leaf hackery:
;;; Change-Ref-Leaf -- Interface
;;;
;;; Change the Leaf that a Ref refers to.
;;;
(defun change-ref-leaf (ref leaf)
(declare (type ref ref) (type leaf leaf))
(unless (eq (ref-leaf ref) leaf)
(push ref (leaf-refs leaf))
(delete-ref ref)
(setf (ref-leaf ref) leaf)
(derive-node-type ref (leaf-type leaf))
(reoptimize-continuation (node-cont ref)))
(undefined-value))
;;; Substitute-Leaf -- Interface
;;;
;;; Change all Refs for Old-Leaf to New-Leaf.
;;;
(defun substitute-leaf (new-leaf old-leaf)
(declare (type leaf new-leaf old-leaf))
(dolist (ref (leaf-refs old-leaf))
(change-ref-leaf ref new-leaf))
(undefined-value))
;;; Find-Constant -- Interface
;;;
;;; Return a Leaf which represents the specified constant object. If the
;;; object is not in *constants*, then we create a new constant Leaf and
;;; enter it.
;;;
(defun find-constant (object)
(or (gethash object *constants*)
(setf (gethash object *constants*)
(make-constant :value object :name nil
:type (ctype-of object)
:where-from :defined))))
;;;; Find-NLX-Info -- Interface
;;;
;;; If there is a non-local exit noted in Entry's environment that exits to
;;; Cont in that entry, then return it, otherwise return NIL.
;;;
(defun find-nlx-info (entry cont)
(declare (type entry entry) (type continuation cont))
(dolist (nlx (environment-nlx-info (node-environment entry)) nil)
(let* ((cleanup (nlx-info-cleanup nlx))
(entry-cleanup (ecase (cleanup-kind cleanup)
((:catch :unwind-protect)
(cleanup-enclosing cleanup))
(:entry cleanup))))
(when (and (eq (nlx-info-continuation nlx) cont)
(eq (continuation-use (cleanup-start entry-cleanup))
entry))
(return nlx)))))
;;;; Functional hackery:
;;; Main-Entry -- Interface
;;;
;;; If Functional is a Lambda, just return it; if it is an
;;; optional-dispatch, return the main-entry.
;;;
(proclaim '(function main-entry (functional) lambda))
(defun main-entry (functional)
(if (lambda-p functional)
functional
(optional-dispatch-main-entry functional)))
;;; Looks-Like-An-MV-Bind -- Interface
;;;
;;; Returns true if Functional is a thing that can be treated like MV-Bind
;;; when it appears in an MV-Call. All fixed arguments must be optional with
;;; null default and no supplied-p. There must be a rest arg with no
;;; references.
;;;
(proclaim '(function looks-like-an-mv-bind (functional) boolean))
(defun looks-like-an-mv-bind (functional)
(and (optional-dispatch-p functional)
(do ((arg (optional-dispatch-arglist functional) (cdr arg)))
((null arg) nil)
(let ((info (lambda-var-arg-info (car arg))))
(unless info (return nil))
(case (arg-info-kind info)
(:optional
(when (or (arg-info-supplied-p info) (arg-info-default info))
(return nil)))
(:rest
(return (and (null (cdr arg)) (null (leaf-refs (car arg))))))
(t
(return nil)))))))
;;; External-Entry-Point-P -- Interface
;;;
;;; Return true if function is an XEP. This is true of normal XEPs
;;; (:External kind) and top-level lambdas (:Top-Level kind.)
;;;
(defun external-entry-point-p (fun)
(declare (type functional fun))
(not (null (member (functional-kind fun) '(:external :top-level)))))
;;; Continuation-Function-Name -- Interface
;;;
;;; If Cont's only use is a global function reference, then return the
;;; referenced symbol, otherwise NIL.
;;;
(defun continuation-function-name (cont)
(declare (type continuation cont))
(let ((use (continuation-use cont)))
(if (ref-p use)
(let ((leaf (ref-leaf use)))
(if (and (global-var-p leaf)
(eq (global-var-kind leaf) :global-function))
(leaf-name leaf)
nil))
nil)))
;;; LET-COMBINATION -- Interface
;;;
;;; Return the COMBINATION node that is the call to the let Fun.
;;;
(defun let-combination (fun)
(declare (type clambda fun))
(assert (eq (functional-kind fun) :let))
(continuation-dest (node-cont (first (leaf-refs fun)))))