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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")
(export '(*compiler-notification-function*))
(in-package "EXTENSIONS")
(export '(*error-print-level* *error-print-length*
*source-context-take-car-forms* *undefined-warning-limit*
*enclosing-source-cutoff*))
(in-package "C")
;;; Node-Enclosing-Cleanup -- Interface
;;; Return the innermost cleanup enclosing Node, or NIL if there is none in
;;; its function. If Node has no cleanup, but is in a let, then we must still
;;; check the environment that the call is in.
(defun node-enclosing-cleanup (node)
(declare (type node node))
(do ((lexenv (node-lexenv node)
(lambda-call-lexenv (lexenv-lambda lexenv))))
((null lexenv) nil)
(let ((cup (lexenv-cleanup lexenv)))
(when cup (return cup)))))
;;; 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. If Cleanup is
;;; supplied, then convert with that cleanup.
(defun insert-cleanup-code (block1 block2 node form &optional cleanup)
(declare (type cblock block1 block2) (type node node)
(type (or cleanup null) cleanup))
(with-ir1-environment node
(let* ((start (make-continuation))
(block (continuation-starts-block start))
(cont (make-continuation))
(*lexical-environment*
(if cleanup
(make-lexenv :cleanup cleanup)
*lexical-environment*)))
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(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 :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 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)
(delete-continuation-use node)
(add-continuation-use node new))
(reoptimize-continuation new)
(undefined-value))
;;;; Misc shortand functions:
;;; NODE-HOME-LAMBDA -- Interface
;;;
;;; Return the home (i.e. enclosing non-let) lambda for Node. Since the
;;; LEXENV-LAMBDA may be deleted, we must chain up the LAMBDA-CALL-LEXENV
;;; thread until we find a lambda that isn't deleted, and then return its home.
;;;
(declaim (maybe-inline node-home-lambda))
(defun node-home-lambda (node)
(declare (type node node))
(do ((fun (lexenv-lambda (node-lexenv node))
(lexenv-lambda (lambda-call-lexenv fun))))
((not (eq (functional-kind fun) :deleted))
(lambda-home fun))
(when (eq (lambda-home fun) fun)
(return fun))))
;;; NODE-xxx -- Interface
(declaim (inline node-block node-tlf-number))
(declaim (maybe-inline node-environment))
(defun node-block (node)
(declare (type node node))
(the cblock (continuation-block (node-prev node))))
;;;
(defun node-environment (node)
(declare (type node node) (inline node-home-lambda))
(the environment (lambda-environment (node-home-lambda node))))
;;; BLOCK-xxx-CLEANUP -- Interface
;;;
;;; Return the enclosing cleanup for environment of the first or last node
;;; in Block.
;;;
(defun block-start-cleanup (block)
(declare (type cblock block))
(node-enclosing-cleanup (continuation-next (block-start block))))
;;;
(defun block-end-cleanup (block)
(declare (type cblock block))
(node-enclosing-cleanup (block-last block)))
;;; BLOCK-HOME-LAMBDA -- Interface
;;;
;;; Return the non-let lambda that holds Block's code.
;;;
(defun block-home-lambda (block)
(declare (type cblock block) (inline node-home-lambda))
(node-home-lambda (block-last block)))
;;; BLOCK-ENVIRONMENT -- Interface
;;;
;;; Return the IR1 environment for Block.
;;;
(defun block-environment (block)
(declare (type cblock block) (inline node-home-lambda))
(lambda-environment (node-home-lambda (block-last block))))
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;;; SOURCE-PATH-TLF-NUMBER -- Interface
;;;
;;; Return the Top Level Form number of path, i.e. the ordinal number of
;;; its orignal source's top-level form in its compilation unit.
;;;
(defun source-path-tlf-number (path)
(declare (list path))
(car (last path)))
;;; SOURCE-PATH-ORIGINAL-SOURCE -- Interface
;;;
;;; Return the (reversed) list for the path in the orignal source (with the
;;; TLF number last.)
;;;
(defun source-path-original-source (path)
(declare (list path))
(cddr (member 'original-source-start path)))
;;; SOURCE-PATH-FORM-NUMBER -- Interface
;;;
;;; Return the Form Number of Path's orignal source inside the Top Level
;;; Form that contains it. This is determined by the order that we walk the
;;; subforms of the top level source form.
;;;
(defun source-path-form-number (path)
(declare (list path))
(cadr (member 'original-source-start path)))
;;; SOURCE-PATH-FORMS -- Interface
;;;
;;; Return a list of all the enclosing forms not in the original source that
;;; converted to get to this form, with the immediate source for node at the
;;; start of the list.
;;;
(defun source-path-forms (path)
(subseq path 0 (position 'original-source-start path)))
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;;; MAKE-LEXENV -- Interface
;;;
;;; Return a new LEXENV just like Default except for the specified slot
;;; values. Values for the alist slots are NCONC'ed to the beginning of the
;;; current value, rather than replacing it entirely.
;;;
(defun make-lexenv (&key (default *lexical-environment*)
functions variables blocks tags type-restrictions
inlines
(lambda (lexenv-lambda default))
(cleanup (lexenv-cleanup default))
(cookie (lexenv-cookie default)))
(macrolet ((frob (var slot)
`(let ((old (,slot default)))
(if ,var
(nconc ,var old)
old))))
(internal-make-lexenv
(frob functions lexenv-functions)
(frob variables lexenv-variables)
(frob blocks lexenv-blocks)
(frob tags lexenv-tags)
(frob type-restrictions lexenv-type-restrictions)
(frob inlines lexenv-inlines)
lambda cleanup cookie)))
#|
functions
variables
blocks
tags
type-restrictions
inlines
|#
;;; Link-Blocks -- Interface
;;; Join Block1 and Block2.
(declare (type cblock block1 block2))
(assert (not (member block2 (block-succ block1))))
(push block2 (block-succ block1))
(push block1 (block-pred block2))
(undefined-value))
;;; UNLINK-BLOCKS -- Interface
;;;
;;; Like LINK-BLOCKS, but we separate BLOCK1 and BLOCK2. If this leaves a
;;; successor with a single predecessor that ends in an IF, then set
;;; BLOCK-TEST-MODIFIED so that any test constraint will now be able to be
;;; propagated to the successor.
(declare (type cblock block1 block2))
(assert (member block2 (block-succ block1)))
(setf (block-succ block1)
(delete block2 (block-succ block1)))
(let ((new-pred (delete block1 (block-pred block2))))
(setf (block-pred block2) new-pred)
(when (and new-pred (null (rest new-pred)))
(let ((pred-block (first new-pred)))
(when (if-p (block-last pred-block))
(setf (block-test-modified pred-block) t)))))
(undefined-value))
;;; 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. We also set
;;; BLOCK-TEST-MODIFIED so that any test constraint will be applied to the new
;;; successor.
;;;
(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)
(setf (block-test-modified block) t)
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(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.
;;;
(defun add-to-dfo (block after)
(declare (type cblock 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))
(undefined-value))
;;; 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 :component nil))
(tail (make-block-key :start 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.
;;; The new block is added to the DFO immediately following Node's block.
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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))
(new-block
(make-block-key :start start
: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))
(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))
;;; REOPTIMIZE-LAMBDA-VAR -- Internal
;;;
;;; Note that something interesting has happened to Var. We only deal with
;;; LET variables, marking the corresponding initial value arg as needing to be
;;; reoptimized.
;;;
(defun reoptimize-lambda-var (var)
(declare (type lambda-var var))
(let ((fun (lambda-var-home var)))
(when (and (eq (functional-kind fun) :let)
(leaf-refs var))
(reoptimize-continuation
(elt (basic-combination-args
(continuation-dest
(node-cont
(first (leaf-refs fun)))))
(position var (lambda-vars fun))))))
(undefined-value))
;;; DELETE-FUNCTIONAL -- Interface
;;;
;;; This function deletes functions that have no references. This need only
;;; be called on functions that never had any references, since otherwise
;;; DELETE-REF will handle the deletion.
;;;
(defun delete-functional (fun)
(assert (null (leaf-refs fun)))
(etypecase fun
(optional-dispatch (delete-optional-dispatch fun))
(clambda (delete-lambda fun)))
(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 was never referenced, we give
;;; a note.
;;;
;;; 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))
(bind (lambda-bind leaf)))
(assert (not (member kind '(:deleted :optional :top-level))))
(setf (functional-kind leaf) :deleted)
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