;;;; This file contains utilities for debugging the compiler --
;;;; currently only stuff for checking the consistency of the IR1.

;;;; This software is part of the SBCL system. See the README file for
;;;; more information.
;;;;
;;;; This software is derived from the CMU CL system, which was
;;;; written at Carnegie Mellon University and released into the
;;;; public domain. The software is in the public domain and is
;;;; provided with absolutely no warranty. See the COPYING and CREDITS
;;;; files for more information.

(in-package "SB!C")

(defvar *args* ()
  #!+sb-doc
  "This variable is bound to the format arguments when an error is signalled
  by BARF or BURP.")

(defvar *ignored-errors* (make-hash-table :test 'equal))

;;; A definite inconsistency has been detected. Signal an error with
;;; *args* bound to the list of the format args.
(declaim (ftype (function (string &rest t) (values)) barf))
(defun barf (string &rest *args*)
  (unless (gethash string *ignored-errors*)
    (restart-case
	(apply #'error string *args*)
      (continue ()
	:report "Ignore this error.")
      (ignore-all ()
	:report "Ignore this and all future occurrences of this error."
	(setf (gethash string *ignored-errors*) t))))
  (values))

(defvar *burp-action* :warn
  #!+sb-doc
  "Action taken by the BURP function when a possible compiler bug is detected.
  One of :WARN, :ERROR or :NONE.")
(declaim (type (member :warn :error :none) *burp-action*))

;;; Called when something funny but possibly correct is noticed.
;;; Otherwise similar to BARF.
(declaim (ftype (function (string &rest t) (values)) burp))
(defun burp (string &rest *args*)
  (ecase *burp-action*
    (:warn (apply #'warn string *args*))
    (:error (apply #'cerror "press on anyway." string *args*))
    (:none))
  (values))

;;; *SEEN-BLOCKS* is a hashtable with true values for all blocks which
;;; appear in the DFO for one of the specified components.
;;;
;;; *SEEN-FUNS* is similar, but records all the lambdas we
;;; reached by recursing on top level functions.
;;; FIXME: Is it really only LAMBDAs, not e.g. FUNCTIONALs? Then
;;; shouldn't it be *SEEN-LAMBDAS*?
(defvar *seen-blocks* (make-hash-table :test 'eq))
(defvar *seen-funs* (make-hash-table :test 'eq))

;;; Barf if NODE is in a block which wasn't reached during the graph
;;; walk.
(declaim (ftype (function (node) (values)) check-node-reached))
(defun check-node-reached (node)
  (unless (gethash (ctran-block (node-prev node)) *seen-blocks*)
    (barf "~S was not reached." node))
  (values))

;;; Check everything that we can think of for consistency. When a
;;; definite inconsistency is detected, we BARF. Possible problems
;;; just cause us to BURP. Our argument is a list of components, but
;;; we also look at the *FREE-VARS*, *FREE-FUNS* and *CONSTANTS*.
;;;
;;; First we do a pre-pass which finds all the CBLOCKs and CLAMBDAs,
;;; testing that they are linked together properly and entering them
;;; in hashtables. Next, we iterate over the blocks again, looking at
;;; the actual code and control flow. Finally, we scan the global leaf
;;; hashtables, looking for lossage.
(declaim (ftype (function (list) (values)) check-ir1-consistency))
(defun check-ir1-consistency (components)
  (clrhash *seen-blocks*)
  (clrhash *seen-funs*)
  (dolist (c components)
    (let* ((head (component-head c))
	   (tail (component-tail c)))
      (unless (and (null (block-pred head))
		   (null (block-succ tail)))
	(barf "~S is malformed." c))

      (do ((prev nil block)
	   (block head (block-next block)))
	  ((null block)
	   (unless (eq prev tail)
	     (barf "wrong TAIL for DFO, ~S in ~S" prev c)))
	(setf (gethash block *seen-blocks*) t)
	(unless (eq (block-prev block) prev)
	  (barf "bad PREV for ~S, should be ~S" block prev))
	(unless (or (eq block tail)
		    (eq (block-component block) c))
	  (barf "~S is not in ~S." block c)))
#|
      (when (or (loop-blocks c) (loop-inferiors c))
	(do-blocks (block c :both)
	  (setf (block-flag block) nil))
	(check-loop-consistency c nil)
	(do-blocks (block c :both)
	  (unless (block-flag block)
	    (barf "~S was not in any loop." block))))
|#
    ))

  (check-fun-consistency components)

  (dolist (c components)
    (do ((block (block-next (component-head c)) (block-next block)))
	((null (block-next block)))
      (check-block-consistency block)))

  (maphash (lambda (k v)
	     (declare (ignore k))
	     (unless (or (constant-p v)
			 (and (global-var-p v)
			      (member (global-var-kind v)
				      '(:global :special))))
	       (barf "strange *FREE-VARS* entry: ~S" v))
	     (dolist (n (leaf-refs v))
	       (check-node-reached n))
	     (when (basic-var-p v)
	       (dolist (n (basic-var-sets v))
		 (check-node-reached n))))
	   *free-vars*)

  (maphash (lambda (k v)
	     (declare (ignore k))
	     (unless (constant-p v)
	       (barf "strange *CONSTANTS* entry: ~S" v))
	     (dolist (n (leaf-refs v))
	       (check-node-reached n)))
	   *constants*)

  (maphash (lambda (k v)
	     (declare (ignore k))
	     (unless (or (functional-p v)
			 (and (global-var-p v)
			      (eq (global-var-kind v) :global-function)))
	       (barf "strange *FREE-FUNS* entry: ~S" v))
	     (dolist (n (leaf-refs v))
	       (check-node-reached n)))
	   *free-funs*)
  (clrhash *seen-funs*)
  (clrhash *seen-blocks*)
  (values))

;;;; function consistency checking

(defun observe-functional (x)
  (declare (type functional x))
  (when (gethash x *seen-funs*)
    (barf "~S was seen more than once." x))
  (unless (eq (functional-kind x) :deleted)
    (setf (gethash x *seen-funs*) t)))

;;; Check that the specified function has been seen.
(defun check-fun-reached (fun where)
  (declare (type functional fun))
  (unless (gethash fun *seen-funs*)
    (barf "unseen function ~S in ~S" fun where)))

;;; In a CLAMBDA, check that the associated nodes are in seen blocks.
;;; In an OPTIONAL-DISPATCH, check that the entry points were seen. If
;;; the function is deleted, ignore it.
(defun check-fun-stuff (functional)
  (ecase (functional-kind functional)
    (:external
     (let ((fun (functional-entry-fun functional)))
       (check-fun-reached fun functional)
       (when (functional-kind fun)
	 (barf "The function for XEP ~S has kind." functional))
       (unless (eq (functional-entry-fun fun) functional)
	 (barf "bad back-pointer in function for XEP ~S" functional))))
    ((:let :mv-let :assignment) ; i.e. SOMEWHAT-LETLIKE-P
     (check-fun-reached (lambda-home functional) functional)
     (when (functional-entry-fun functional)
       (barf "The LET ~S has entry function." functional))
     (unless (member functional (lambda-lets (lambda-home functional)))
       (barf "The LET ~S is not in LETs for HOME." functional))
     (unless (eq (functional-kind functional) :assignment)
       (when (rest (leaf-refs functional))
	 (barf "The LET ~S has multiple references." functional)))
     (when (lambda-lets functional)
       (barf "LETs in a LET: ~S" functional)))
    (:optional
     (when (functional-entry-fun functional)
       (barf ":OPTIONAL ~S has an ENTRY-FUN." functional))
     (let ((ef (lambda-optional-dispatch functional)))
       (check-fun-reached ef functional)
       (unless (or (member functional (optional-dispatch-entry-points ef))
		   (eq functional (optional-dispatch-more-entry ef))
		   (eq functional (optional-dispatch-main-entry ef)))
	 (barf ":OPTIONAL ~S is not an e-p for its OPTIONAL-DISPATCH ~S."
	       functional ef))))
    (:toplevel
     (unless (eq (functional-entry-fun functional) functional)
       (barf "The ENTRY-FUN in ~S isn't a self-pointer." functional)))
    ((nil :escape :cleanup)
     (let ((ef (functional-entry-fun functional)))
       (when ef
	 (check-fun-reached ef functional)
	 (unless (eq (functional-kind ef) :external)
	   (barf "The ENTRY-FUN in ~S isn't an XEP: ~S." functional ef)))))
    (:deleted
     (return-from check-fun-stuff)))

  (case (functional-kind functional)
    ((nil :optional :external :toplevel :escape :cleanup)
     (when (lambda-p functional)
       (dolist (fun (lambda-lets functional))
	 (unless (eq (lambda-home fun) functional)
	   (barf "The home in ~S is not ~S." fun functional))
	 (check-fun-reached fun functional))
       (unless (eq (lambda-home functional) functional)
	 (barf "home not self-pointer in ~S" functional)))))

  (etypecase functional
    (clambda
     (when (lambda-bind functional)
       (check-node-reached (lambda-bind functional)))
     (when (lambda-return functional)
       (check-node-reached (lambda-return functional)))

     (dolist (var (lambda-vars functional))
       (dolist (ref (leaf-refs var))
	 (check-node-reached ref))
       (dolist (set (basic-var-sets var))
	 (check-node-reached set))
       (unless (eq (lambda-var-home var) functional)
	 (barf "HOME in ~S should be ~S." var functional))))
    (optional-dispatch
     (dolist (ep (optional-dispatch-entry-points functional))
       (check-fun-reached ep functional))
     (let ((more (optional-dispatch-more-entry functional)))
       (when more (check-fun-reached more functional)))
     (check-fun-reached (optional-dispatch-main-entry functional)
			functional))))

(defun check-fun-consistency (components)
  (dolist (c components)
    (dolist (new-fun (component-new-functionals c))
      (observe-functional new-fun))
    (dolist (fun (component-lambdas c))
      (when (eq (functional-kind fun) :external)
	(let ((ef (functional-entry-fun fun)))
	  (when (optional-dispatch-p ef)
	    (observe-functional ef))))
      (observe-functional fun)
      (dolist (let (lambda-lets fun))
	(observe-functional let))))

  (dolist (c components)
    (dolist (new-fun (component-new-functionals c))
      (check-fun-stuff new-fun))
    (dolist (fun (component-lambdas c))
      (when (eq (functional-kind fun) :deleted)
	(barf "deleted lambda ~S in Lambdas for ~S" fun c))
      (check-fun-stuff fun)
      (dolist (let (lambda-lets fun))
	(check-fun-stuff let)))))

;;;; loop consistency checking

#|
;;; Descend through the loop nesting and check that the tree is well-formed
;;; and that all blocks in the loops are known blocks. We also mark each block
;;; that we see so that we can do a check later to detect blocks that weren't
;;; in any loop.
(declaim (ftype (function (loop (or loop null)) (values)) check-loop-consistency))
(defun check-loop-consistency (loop superior)
  (unless (eq (loop-superior loop) superior)
    (barf "wrong superior in ~S, should be ~S" loop superior))
  (when (and superior
	     (/= (loop-depth loop) (1+ (loop-depth superior))))
    (barf "wrong depth in ~S" loop))

  (dolist (tail (loop-tail loop))
    (check-loop-block tail loop))
  (dolist (exit (loop-exits loop))
    (check-loop-block exit loop))
  (check-loop-block (loop-head loop) loop)
  (unless (eq (block-loop (loop-head loop)) loop)
    (barf "The head of ~S is not directly in the loop." loop))

  (do ((block (loop-blocks loop) (block-loop-next block)))
      ((null block))
    (setf (block-flag block) t)
    (unless (gethash block *seen-blocks*)
      (barf "unseen block ~S in Blocks for ~S" block loop))
    (unless (eq (block-loop block) loop)
      (barf "wrong loop in ~S, should be ~S" block loop)))

  (dolist (inferior (loop-inferiors loop))
    (check-loop-consistency inferior loop))
  (values))

;;; Check that Block is either in Loop or an inferior.
(declaim (ftype (function (block loop) (values)) check-loop-block))
(defun check-loop-block (block loop)
  (unless (gethash block *seen-blocks*)
    (barf "unseen block ~S in loop info for ~S" block loop))
  (labels ((walk (l)
	     (if (eq (block-loop block) l)
		 t
		 (dolist (inferior (loop-inferiors l) nil)
		   (when (walk inferior) (return t))))))
    (unless (walk loop)
      (barf "~S is in loop info for ~S but not in the loop." block loop)))
  (values))

|#

;;; Check a block for consistency at the general flow-graph level, and
;;; call CHECK-NODE-CONSISTENCY on each node to locally check for
;;; semantic consistency.
(declaim (ftype (function (cblock) (values)) check-block-consistency))
(defun check-block-consistency (block)

  (dolist (pred (block-pred block))
    (unless (gethash pred *seen-blocks*)
      (barf "unseen predecessor ~S in ~S" pred block))
    (unless (member block (block-succ pred))
      (barf "bad predecessor link ~S in ~S" pred block)))

  (let* ((fun (block-home-lambda block))
	 (fun-deleted (eq (functional-kind fun) :deleted))
	 (this-ctran (block-start block))
	 (last (block-last block)))
    (unless fun-deleted
      (check-fun-reached fun block))
    (when (not this-ctran)
      (barf "~S has no START." block))
    (when (not last)
      (barf "~S has no LAST." block))
    (unless (eq (ctran-kind this-ctran) :block-start)
      (barf "The START of ~S has the wrong kind." block))

    (when (ctran-use this-ctran)
      (barf "The ctran ~S is used." this-ctran))

    (when (node-next last)
      (barf "Last node ~S of ~S has next ctran." last block))

    (loop
      (unless (eq (ctran-block this-ctran) block)
	(barf "BLOCK of ~S should be ~S." this-ctran block))

      (let ((node (ctran-next this-ctran)))
	(unless (node-p node)
	  (barf "~S has strange NEXT." this-ctran))
	(unless (eq (node-prev node) this-ctran)
	  (barf "PREV in ~S should be ~S." node this-ctran))

        (when (valued-node-p node)
          (binding* ((lvar (node-lvar node) :exit-if-null))
            (unless (memq node (find-uses lvar))
              (barf "~S is not used by its LVAR ~S." node lvar))
            (when (singleton-p (lvar-uses lvar))
              (barf "~S has exactly 1 use, but LVAR-USES is a list."
                    lvar))
            (unless (lvar-dest lvar)
              (barf "~S does not have dest." lvar))))

        (check-node-reached node)
	(unless fun-deleted
	  (check-node-consistency node))

	(let ((next (node-next node)))
	  (when (and (not next) (not (eq node last)))
	    (barf "~S has no NEXT." node))
	  (when (eq node last) (return))
	  (unless (eq (ctran-kind next) :inside-block)
	    (barf "The interior ctran ~S in ~S has the wrong kind."
		  next
		  block))
	  (unless (ctran-next next)
	    (barf "~S has no NEXT." next))
	  (unless (eq (ctran-use next) node)
	    (barf "USE in ~S should be ~S." next node))
	  (setq this-ctran next))))

    (check-block-successors block))
  (values))

;;; Check that BLOCK is properly terminated. Each successor must be
;;; accounted for by the type of the last node.
(declaim (ftype (function (cblock) (values)) check-block-successors))
(defun check-block-successors (block)
  (let ((last (block-last block))
	(succ (block-succ block)))

    (let* ((comp (block-component block)))
      (dolist (b succ)
	(unless (gethash b *seen-blocks*)
	  (barf "unseen successor ~S in ~S" b block))
	(unless (member block (block-pred b))
	  (barf "bad successor link ~S in ~S" b block))
	(unless (eq (block-component b) comp)
	  (barf "The successor ~S in ~S is in a different component."
		b
		block))))

    (typecase last
      (cif
       (unless (proper-list-of-length-p succ 1 2)
	 (barf "~S ends in an IF, but doesn't have one or two succesors."
	       block))
       (unless (member (if-consequent last) succ)
	 (barf "The CONSEQUENT for ~S isn't in SUCC for ~S." last block))
       (unless (member (if-alternative last) succ)
	 (barf "The ALTERNATIVE for ~S isn't in SUCC for ~S." last block)))
      (creturn
       (unless (if (eq (functional-kind (return-lambda last)) :deleted)
		   (null succ)
		   (and (= (length succ) 1)
			(eq (first succ)
			    (component-tail (block-component block)))))
	 (barf "strange successors for RETURN in ~S" block)))
      (exit
       (unless (proper-list-of-length-p succ 0 1)
	 (barf "EXIT node with strange number of successors: ~S" last)))
      (t
       (unless (or (= (length succ) 1) (node-tail-p last)
		   (and (block-delete-p block) (null succ)))
	 (barf "~S ends in normal node, but doesn't have one successor."
	       block)))))
  (values))

;;;; node consistency checking

;;; Check that the DEST for LVAR is the specified NODE. We also mark
;;; the block LVAR is in as SEEN.
#+nil(declaim (ftype (function (lvar node) (values)) check-dest))
(defun check-dest (lvar node)
  (do-uses (use lvar)
    (unless (gethash (node-block use) *seen-blocks*)
      (barf "Node ~S using ~S is in an unknown block." use lvar)))
  (unless (eq (lvar-dest lvar) node)
    (barf "DEST for ~S should be ~S." lvar node))
  (unless (find-uses lvar)
    (barf "Lvar ~S has a destinatin, but no uses."
          lvar))
  (values))

;;; This function deals with checking for consistency of the
;;; type-dependent information in a node.
(defun check-node-consistency (node)
  (declare (type node node))
  (etypecase node
    (ref
     (let ((leaf (ref-leaf node)))
       (when (functional-p leaf)
	 (if (eq (functional-kind leaf) :toplevel-xep)
	     (unless (eq (component-kind (block-component (node-block node)))
			 :toplevel)
	       (barf ":TOPLEVEL-XEP ref in non-top-level component: ~S"
		     node))
	     (check-fun-reached leaf node)))))
    (basic-combination
     (check-dest (basic-combination-fun node) node)
     (when (and (mv-combination-p node)
                (eq (basic-combination-kind node) :local))
       (let ((fun-lvar (basic-combination-fun node)))
         (unless (ref-p (lvar-uses fun-lvar))
           (barf "function in a local mv-combination is not a LEAF: ~S" node))
         (let ((fun (ref-leaf (lvar-use fun-lvar))))
           (unless (lambda-p fun)
             (barf "function ~S in a local mv-combination ~S is not local"
                   fun node))
           (unless (eq (functional-kind fun) :mv-let)
             (barf "function ~S in a local mv-combination ~S is not of kind :MV-LET"
                   fun node)))))
     (dolist (arg (basic-combination-args node))
       (cond
         (arg (check-dest arg node))
         ((not (and (eq (basic-combination-kind node) :local)
                    (combination-p node)))
          (barf "flushed arg not in local call: ~S" node))
         (t
          (locally
              ;; KLUDGE: In sbcl-0.6.11.37, the compiler doesn't like
              ;; (DECLARE (TYPE INDEX POS)) after the inline expansion of
              ;; POSITION. It compiles it correctly, but it issues a type
              ;; mismatch warning because it can't eliminate the
              ;; possibility that control will flow through the
              ;; NIL-returning branch. So we punt here. -- WHN 2001-04-15
              (declare (notinline position))
            (let ((fun (ref-leaf (lvar-use
                                  (basic-combination-fun node))))
                  (pos (position arg (basic-combination-args node))))
              (declare (type index pos))
              (when (leaf-refs (elt (lambda-vars fun) pos))
                (barf "flushed arg for referenced var in ~S" node)))))))
     (let* ((lvar (node-lvar node))
            (dest (and lvar (lvar-dest lvar))))
       (when (and (return-p dest)
		  (eq (basic-combination-kind node) :local)
		  (not (eq (lambda-tail-set (combination-lambda node))
			   (lambda-tail-set (return-lambda dest)))))
	 (barf "tail local call to function with different tail set:~%  ~S"
	       node))))
    (cif
     (check-dest (if-test node) node)
     (unless (eq (block-last (node-block node)) node)
       (barf "IF not at block end: ~S" node)))
    (cset
     (check-dest (set-value node) node))
    (cast
     (check-dest (cast-value node) node))
    (bind
     (check-fun-reached (bind-lambda node) node))
    (creturn
     (check-fun-reached (return-lambda node) node)
     (check-dest (return-result node) node)
     (unless (eq (block-last (node-block node)) node)
       (barf "RETURN not at block end: ~S" node)))
    (entry
     (unless (member node (lambda-entries (node-home-lambda node)))
       (barf "~S is not in ENTRIES for its home LAMBDA." node))
     (dolist (exit (entry-exits node))
       (unless (node-deleted exit)
	 (check-node-reached node))))
    (exit
     (let ((entry (exit-entry node))
	   (value (exit-value node)))
       (cond (entry
	      (check-node-reached entry)
	      (unless (member node (entry-exits entry))
		(barf "~S is not in its ENTRY's EXITS." node))
	      (when value
		(check-dest value node)))
	     (t
	      (when value
		(barf "~S has VALUE but no ENTRY." node)))))))

  (values))

;;;; IR2 consistency checking

;;; Check for some kind of consistency in some REFs linked together by
;;; TN-REF-ACROSS. VOP is the VOP that the references are in. WRITE-P
;;; is the value of WRITE-P that should be present. COUNT is the
;;; minimum number of operands expected. If MORE-P is true, then any
;;; larger number will also be accepted. WHAT is a string describing
;;; the kind of operand in error messages.
(defun check-tn-refs (refs vop write-p count more-p what)
  (let ((vop-refs (vop-refs vop)))
    (do ((ref refs (tn-ref-across ref))
	 (num 0 (1+ num)))
	((null ref)
	 (when (< num count)
	   (barf "There should be at least ~W ~A in ~S, but there are only ~W."
		 count what vop num))
	 (when (and (not more-p) (> num count))
	   (barf "There should be ~W ~A in ~S, but are ~W."
		 count what vop num)))
      (unless (eq (tn-ref-vop ref) vop)
	(barf "VOP is ~S isn't ~S." ref vop))
      (unless (eq (tn-ref-write-p ref) write-p)
	(barf "The WRITE-P in ~S isn't ~S." vop write-p))
      (unless (find-in #'tn-ref-next-ref ref vop-refs)
	(barf "~S not found in REFS for ~S" ref vop))
      (unless (find-in #'tn-ref-next ref
		       (if (tn-ref-write-p ref)
			   (tn-writes (tn-ref-tn ref))
			   (tn-reads (tn-ref-tn ref))))
	(barf "~S not found in reads/writes for its TN" ref))

      (let ((target (tn-ref-target ref)))
	(when target
	  (unless (eq (tn-ref-write-p target) (not (tn-ref-write-p ref)))
	    (barf "The target for ~S isn't complementary WRITE-P." ref))
	  (unless (find-in #'tn-ref-next-ref target vop-refs)
	    (barf "The target for ~S isn't in REFS for ~S." ref vop)))))))

;;; Verify the sanity of the VOP-REFS slot in VOP. This involves checking
;;; that each referenced TN appears as an argument, result or temp, and also
;;; basic checks for the plausibility of the specified ordering of the refs.
(defun check-vop-refs (vop)
  (declare (type vop vop))
  (do ((ref (vop-refs vop) (tn-ref-next-ref ref)))
      ((null ref))
    (cond
     ((find-in #'tn-ref-across ref (vop-args vop)))
     ((find-in #'tn-ref-across ref (vop-results vop)))
     ((not (eq (tn-ref-vop ref) vop))
      (barf "VOP in ~S isn't ~S." ref vop))
     ((find-in #'tn-ref-across ref (vop-temps vop)))
     ((tn-ref-write-p ref)
      (barf "stray ref that isn't a READ: ~S" ref))
     (t
      (let* ((tn (tn-ref-tn ref))
	     (temp (find-in #'tn-ref-across tn (vop-temps vop)
			    :key #'tn-ref-tn)))
	(unless temp
	  (barf "stray ref with no corresponding temp write: ~S" ref))
	(unless (find-in #'tn-ref-next-ref temp (tn-ref-next-ref ref))
	  (barf "Read is after write for temp ~S in refs of ~S."
		tn vop))))))
  (values))

;;; Check the basic sanity of the VOP linkage, then call some other
;;; functions to check on the TN-REFS. We grab some info out of the
;;; VOP-INFO to tell us what to expect.
;;;
;;; [### Check that operand type restrictions are met?]
(defun check-ir2-block-consistency (2block)
  (declare (type ir2-block 2block))
  (do ((vop (ir2-block-start-vop 2block)
	    (vop-next vop))
       (prev nil vop))
      ((null vop)
       (unless (eq prev (ir2-block-last-vop 2block))
	 (barf "The last VOP in ~S should be ~S." 2block prev)))
    (unless (eq (vop-prev vop) prev)
      (barf "PREV in ~S should be ~S." vop prev))

    (unless (eq (vop-block vop) 2block)
      (barf "BLOCK in ~S should be ~S." vop 2block))

    (check-vop-refs vop)

    (let* ((info (vop-info vop))
	   (atypes (template-arg-types info))
	   (rtypes (template-result-types info)))
      (check-tn-refs (vop-args vop) vop nil
		     (count-if-not (lambda (x)
				     (and (consp x)
					  (eq (car x) :constant)))
				   atypes)
		     (template-more-args-type info) "args")
      (check-tn-refs (vop-results vop) vop t
		     (if (eq rtypes :conditional) 0 (length rtypes))
		     (template-more-results-type info) "results")
      (check-tn-refs (vop-temps vop) vop t 0 t "temps")
      (unless (= (length (vop-codegen-info vop))
		 (template-info-arg-count info))
	(barf "wrong number of codegen info args in ~S" vop))))
  (values))

;;; Check stuff about the IR2 representation of COMPONENT. This assumes the
;;; sanity of the basic flow graph.
;;;
;;; [### Also grovel global TN data structures?  Assume pack not
;;; done yet?  Have separate CHECK-TN-CONSISTENCY for pre-pack and
;;; CHECK-PACK-CONSISTENCY for post-pack?]
(defun check-ir2-consistency (component)
  (declare (type component component))
  (do-ir2-blocks (block component)
    (check-ir2-block-consistency block))
  (values))

;;;; lifetime analysis checking

;;; Dump some info about how many TNs there, and what the conflicts data
;;; structures are like.
(defun pre-pack-tn-stats (component &optional (stream *error-output*))
  (declare (type component component))
  (let ((wired 0)
	(global 0)
	(local 0)
	(confs 0)
	(unused 0)
	(const 0)
	(temps 0)
	(environment 0)
	(comp 0))
    (do-packed-tns (tn component)
      (let ((reads (tn-reads tn))
	    (writes (tn-writes tn)))
	(when (and reads writes
		   (not (tn-ref-next reads)) (not (tn-ref-next writes))
		   (eq (tn-ref-vop reads) (tn-ref-vop writes)))
	  (incf temps)))
      (when (tn-offset tn)
	(incf wired))
      (unless (or (tn-reads tn) (tn-writes tn))
	(incf unused))
      (cond ((eq (tn-kind tn) :component)
	     (incf comp))
	    ((tn-global-conflicts tn)
	     (case (tn-kind tn)
	       ((:environment :debug-environment) (incf environment))
	       (t (incf global)))
	     (do ((conf (tn-global-conflicts tn)
			(global-conflicts-next-tnwise conf)))
		 ((null conf))
	       (incf confs)))
	    (t
	     (incf local))))

    (do ((tn (ir2-component-constant-tns (component-info component))
	     (tn-next tn)))
	((null tn))
      (incf const))

    (format stream
     "~%TNs: ~W local, ~W temps, ~W constant, ~W env, ~W comp, ~W global.~@
       Wired: ~W, Unused: ~W. ~W block~:P, ~W global conflict~:P.~%"
       local temps const environment comp global wired unused
       (ir2-block-count component)
       confs))
  (values))

;;; If the entry in Local-TNs for TN in BLOCK is :MORE, then do some checks
;;; for the validity of the usage.
(defun check-more-tn-entry (tn block)
  (let* ((vop (ir2-block-start-vop block))
	 (info (vop-info vop)))
    (macrolet ((frob (more-p ops)
		 `(and (,more-p info)
		       (find-in #'tn-ref-across tn (,ops vop)
				:key #'tn-ref-tn))))
      (unless (and (eq vop (ir2-block-last-vop block))
		   (or (frob template-more-args-type vop-args)
		       (frob template-more-results-type vop-results)))
	(barf "strange :MORE LTN entry for ~S in ~S" tn block))))
  (values))

(defun check-tn-conflicts (component)
  (do-packed-tns (tn component)
    (unless (or (not (eq (tn-kind tn) :normal))
		(tn-reads tn)
		(tn-writes tn))
      (barf "no references to ~S" tn))

    (unless (tn-sc tn) (barf "~S has no SC." tn))

    (let ((conf (tn-global-conflicts tn))
	  (kind (tn-kind tn)))
      (cond
       ((eq kind :component)
	(unless (member tn (ir2-component-component-tns
			    (component-info component)))
	  (barf "~S not in COMPONENT-TNs for ~S" tn component)))
       (conf
	(do ((conf conf (global-conflicts-next-tnwise conf))
	     (prev nil conf))
	    ((null conf))
	  (unless (eq (global-conflicts-tn conf) tn)
	    (barf "TN in ~S should be ~S." conf tn))

	  (unless (eq (global-conflicts-kind conf) :live)
	    (let* ((block (global-conflicts-block conf))
		   (ltn (svref (ir2-block-local-tns block)
			       (global-conflicts-number conf))))
	      (cond ((eq ltn tn))
		    ((eq ltn :more) (check-more-tn-entry tn block))
		    (t
		     (barf "~S wrong in LTN map for ~S" conf tn)))))

	  (when prev
	    (unless (> (ir2-block-number (global-conflicts-block conf))
		       (ir2-block-number (global-conflicts-block prev)))
	      (barf "~s and ~s out of order" prev conf)))))
       ((member (tn-kind tn) '(:constant :specified-save)))
       (t
	(let ((local (tn-local tn)))
	  (unless local
	    (barf "~S has no global conflicts, but isn't local either." tn))
	  (unless (eq (svref (ir2-block-local-tns local)
			     (tn-local-number tn))
		      tn)
	    (barf "~S wrong in LTN map" tn))
	  (do ((ref (tn-reads tn) (tn-ref-next ref)))
	      ((null ref))
	    (unless (eq (vop-block (tn-ref-vop ref)) local)
	      (barf "~S has references in blocks other than its LOCAL block."
		    tn)))
	  (do ((ref (tn-writes tn) (tn-ref-next ref)))
	      ((null ref))
	    (unless (eq (vop-block (tn-ref-vop ref)) local)
	      (barf "~S has references in blocks other than its LOCAL block."
		    tn))))))))
  (values))

(defun check-block-conflicts (component)
  (do-ir2-blocks (block component)
    (do ((conf (ir2-block-global-tns block)
	       (global-conflicts-next-blockwise conf))
	 (prev nil conf))
	((null conf))
      (when prev
	(unless (> (tn-number (global-conflicts-tn conf))
		   (tn-number (global-conflicts-tn prev)))
	  (barf "~S and ~S out of order in ~S" prev conf block)))

      (unless (find-in #'global-conflicts-next-tnwise
		       conf
		       (tn-global-conflicts
			(global-conflicts-tn conf)))
	(barf "~S missing from global conflicts of its TN" conf)))

    (let ((map (ir2-block-local-tns block)))
      (dotimes (i (ir2-block-local-tn-count block))
	(let ((tn (svref map i)))
	  (unless (or (eq tn :more)
		      (null tn)
		      (tn-global-conflicts tn)
		      (eq (tn-local tn) block))
	    (barf "strange TN ~S in LTN map for ~S" tn block)))))))

;;; All TNs live at the beginning of an environment must be passing
;;; locations associated with that environment. We make an exception
;;; for wired TNs in XEP functions, since we randomly reference wired
;;; TNs to access the full call passing locations.
(defun check-environment-lifetimes (component)
  (dolist (fun (component-lambdas component))
    (let* ((env (lambda-physenv fun))
	   (2env (physenv-info env))
	   (vars (lambda-vars fun))
	   (closure (ir2-physenv-closure 2env))
	   (pc (ir2-physenv-return-pc-pass 2env))
	   (fp (ir2-physenv-old-fp 2env))
	   (2block (block-info (lambda-block (physenv-lambda env)))))
      (do ((conf (ir2-block-global-tns 2block)
		 (global-conflicts-next-blockwise conf)))
	  ((null conf))
	(let ((tn (global-conflicts-tn conf)))
	  (unless (or (eq (global-conflicts-kind conf) :write)
		      (eq tn pc)
		      (eq tn fp)
		      (and (xep-p fun) (tn-offset tn))
		      (member (tn-kind tn) '(:environment :debug-environment))
		      (member tn vars :key #'leaf-info)
		      (member tn closure :key #'cdr))
	    (barf "strange TN live at head of ~S: ~S" env tn))))))
  (values))

;;; Check for some basic sanity in the TN conflict data structures,
;;; and also check that no TNs are unexpectedly live at environment
;;; entry.
(defun check-life-consistency (component)
  (check-tn-conflicts component)
  (check-block-conflicts component)
  (check-environment-lifetimes component))

;;;; pack consistency checking

(defun check-pack-consistency (component)
  (flet ((check (scs ops)
	   (do ((scs scs (cdr scs))
		(op ops (tn-ref-across op)))
	       ((null scs))
	     (let ((load-tn (tn-ref-load-tn op)))
	       (unless (eq (svref (car scs)
				  (sc-number
				   (tn-sc
				    (or load-tn (tn-ref-tn op)))))
			   t)
		 (barf "operand restriction not satisfied: ~S" op))))))
    (do-ir2-blocks (block component)
      (do ((vop (ir2-block-last-vop block) (vop-prev vop)))
	  ((null vop))
	(let ((info (vop-info vop)))
	  (check (vop-info-result-load-scs info) (vop-results vop))
	  (check (vop-info-arg-load-scs info) (vop-args vop))))))
  (values))

;;;; data structure dumping routines

;;; When we print CONTINUATIONs and TNs, we assign them small numeric
;;; IDs so that we can get a handle on anonymous objects given a
;;; printout.
;;;
;;; FIXME:
;;;   * Perhaps this machinery should be #!+SB-SHOW.
;;;   * Probably the hash tables should either be weak hash tables,
;;;     or only allocated within a single compilation unit. Otherwise
;;;     there will be a tendency for them to grow without bound and
;;;     keep garbage from being collected.
(macrolet ((def (counter vto vfrom fto ffrom)
	     `(progn
		(declaim (type hash-table ,vto ,vfrom))
		(defvar ,vto (make-hash-table :test 'eq))
		(defvar ,vfrom (make-hash-table :test 'eql))
		(declaim (type fixnum ,counter))
		(defvar ,counter 0)

		(defun ,fto (x)
		  (or (gethash x ,vto)
		      (let ((num (incf ,counter)))
			(setf (gethash num ,vfrom) x)
			(setf (gethash x ,vto) num))))

		(defun ,ffrom (num)
		  (values (gethash num ,vfrom))))))
  (def *continuation-number* *continuation-numbers* *number-continuations*
       cont-num num-cont)
  (def *tn-id* *tn-ids* *id-tns* tn-id id-tn)
  (def *label-id* *id-labels* *label-ids* label-id id-label))

;;; Print a terse one-line description of LEAF.
(defun print-leaf (leaf &optional (stream *standard-output*))
  (declare (type leaf leaf) (type stream stream))
  (etypecase leaf
    (lambda-var (prin1 (leaf-debug-name leaf) stream))
    (constant (format stream "'~S" (constant-value leaf)))
    (global-var
     (format stream "~S {~A}" (leaf-debug-name leaf) (global-var-kind leaf)))
    (functional
     (format stream "~S ~S" (type-of leaf) (functional-debug-name leaf)))))

;;; Attempt to find a block given some thing that has to do with it.
(declaim (ftype (sfunction (t) cblock) block-or-lose))
(defun block-or-lose (thing)
  (ctypecase thing
    (cblock thing)
    (ir2-block (ir2-block-block thing))
    (vop (block-or-lose (vop-block thing)))
    (tn-ref (block-or-lose (tn-ref-vop thing)))
    (ctran (ctran-block thing))
    (node (node-block thing))
    (component (component-head thing))
#|    (cloop (loop-head thing))|#
    (integer (ctran-block (num-cont thing)))
    (functional (lambda-block (main-entry thing)))
    (null (error "Bad thing: ~S." thing))
    (symbol (block-or-lose (gethash thing *free-funs*)))))

;;; Print cN.
(defun print-continuation (cont)
  (declare (type continuation cont))
  (format t " c~D" (cont-num cont))
  (values))

(defun print-ctran (cont)
  (declare (type ctran cont))
  (format t "c~D " (cont-num cont))
  (values))
(defun print-lvar (cont)
  (declare (type lvar cont))
  (format t "v~D " (cont-num cont))
  (values))

;;; Print out the nodes in BLOCK in a format oriented toward
;;; representing what the code does.
(defun print-nodes (block)
  (setq block (block-or-lose block))
  (pprint-logical-block (nil nil)
    (format t "~:@_IR1 block ~D start c~D"
            (block-number block) (cont-num (block-start block)))
    (when (block-delete-p block)
      (format t " <deleted>"))

    (pprint-newline :mandatory)
    (awhen (block-info block)
      (format t "start stack:~{ v~D~}"
              (mapcar #'cont-num (ir2-block-start-stack it)))
      (pprint-newline :mandatory))
    (do ((ctran (block-start block) (node-next (ctran-next ctran))))
        ((not ctran))
      (let ((node (ctran-next ctran)))
        (format t "~3D>~:[    ~;~:*~3D:~] "
                (cont-num ctran)
                (when (and (valued-node-p node) (node-lvar node))
                  (cont-num (node-lvar node))))
        (etypecase node
          (ref (print-leaf (ref-leaf node)))
          (basic-combination
           (let ((kind (basic-combination-kind node)))
             (format t "~(~A~A ~A~) "
                     (if (node-tail-p node) "tail " "")
                     kind
                     (type-of node))
             (print-lvar (basic-combination-fun node))
             (dolist (arg (basic-combination-args node))
               (if arg
                   (print-lvar arg)
                   (format t "<none> ")))))
          (cset
           (write-string "set ")
           (print-leaf (set-var node))
           (write-char #\space)
           (print-lvar (set-value node)))
          (cif
           (write-string "if ")
           (print-lvar (if-test node))
           (print-ctran (block-start (if-consequent node)))
           (print-ctran (block-start (if-alternative node))))
          (bind
           (write-string "bind ")
           (print-leaf (bind-lambda node))
           (when (functional-kind (bind-lambda node))
             (format t " ~S ~S" :kind (functional-kind (bind-lambda node)))))
          (creturn
           (write-string "return ")
           (print-lvar (return-result node))
           (print-leaf (return-lambda node)))
          (entry
           (format t "entry ~S" (entry-exits node)))
          (exit
           (let ((value (exit-value node)))
             (cond (value
                    (format t "exit ")
                    (print-lvar value))
                   ((exit-entry node)
                    (format t "exit <no value>"))
                   (t
                    (format t "exit <degenerate>")))))
          (cast
           (let ((value (cast-value node)))
             (format t "cast v~D ~A[~S -> ~S]" (cont-num value)
                     (if (cast-%type-check node) #\+ #\-)
                     (cast-type-to-check node)
                     (cast-asserted-type node)))))
        (pprint-newline :mandatory)))

    (awhen (block-info block)
      (format t "end stack:~{ v~D~}"
              (mapcar #'cont-num (ir2-block-end-stack it)))
      (pprint-newline :mandatory))
    (let ((succ (block-succ block)))
      (format t "successors~{ c~D~}~%"
              (mapcar (lambda (x) (cont-num (block-start x))) succ))))
  (values))

;;; Print the guts of a TN. (logic shared between PRINT-OBJECT (TN T)
;;; and printers for compound objects which contain TNs)
(defun print-tn-guts (tn &optional (stream *standard-output*))
  (declare (type tn tn))
  (let ((leaf (tn-leaf tn)))
    (cond (leaf
	   (print-leaf leaf stream)
	   (format stream "!~D" (tn-id tn)))
	  (t
	   (format stream "t~D" (tn-id tn))))
    (when (and (tn-sc tn) (tn-offset tn))
      (format stream "[~A]" (location-print-name tn)))))

;;; Print the TN-REFs representing some operands to a VOP, linked by
;;; TN-REF-ACROSS.
(defun print-operands (refs)
  (declare (type (or tn-ref null) refs))
  (pprint-logical-block (*standard-output* nil)
    (do ((ref refs (tn-ref-across ref)))
	((null ref))
      (let ((tn (tn-ref-tn ref))
	    (ltn (tn-ref-load-tn ref)))
	(cond ((not ltn)
	       (print-tn-guts tn))
	      (t
	       (print-tn-guts tn)
	       (princ (if (tn-ref-write-p ref) #\< #\>))
	       (print-tn-guts ltn)))
	(princ #\space)
	(pprint-newline :fill)))))

;;; Print the VOP, putting args, info and results on separate lines, if
;;; necessary.
(defun print-vop (vop)
  (pprint-logical-block (*standard-output* nil)
    (princ (vop-info-name (vop-info vop)))
    (princ #\space)
    (pprint-indent :current 0)
    (print-operands (vop-args vop))
    (pprint-newline :linear)
    (when (vop-codegen-info vop)
      (princ (with-output-to-string (stream)
	       (let ((*print-level* 1)
		     (*print-length* 3))
		 (format stream "{~{~S~^ ~}} " (vop-codegen-info vop)))))
      (pprint-newline :linear))
    (when (vop-results vop)
      (princ "=> ")
      (print-operands (vop-results vop))))
  (pprint-newline :mandatory))

;;; Print the VOPs in the specified IR2 block.
(defun print-ir2-block (block)
  (declare (type ir2-block block))
  (pprint-logical-block (*standard-output* nil)
    (cond
      ((eq (block-info (ir2-block-block block)) block)
       (format t "~:@_IR2 block ~D start c~D~:@_"
               (ir2-block-number block)
               (cont-num (block-start (ir2-block-block block))))
       (let ((label (ir2-block-%label block)))
         (when label
           (format t "L~D:~:@_" (label-id label)))))
      (t
       (format t "<overflow>~:@_")))

    (do ((vop (ir2-block-start-vop block)
              (vop-next vop))
         (number 0 (1+ number)))
        ((null vop))
      (format t "~W: " number)
      (print-vop vop))))

;;; This is like PRINT-NODES, but dumps the IR2 representation of the
;;; code in BLOCK.
(defun print-vops (block)
  (setq block (block-or-lose block))
  (let ((2block (block-info block)))
    (print-ir2-block 2block)
    (do ((b (ir2-block-next 2block) (ir2-block-next b)))
	((not (eq (ir2-block-block b) block)))
      (print-ir2-block b)))
  (values))

;;; Scan the IR2 blocks in emission order.
(defun print-ir2-blocks (thing &optional full)
  (let* ((block (component-head (block-component (block-or-lose thing))))
         (2block (block-info block)))
    (pprint-logical-block (nil nil)
      (loop while 2block
         do (setq block (ir2-block-block 2block))
         do (pprint-logical-block (*standard-output* nil)
              (if full
                  (print-nodes block)
                  (format t "IR1 block ~D start c~D"
                          (block-number block)
                          (cont-num (block-start block))))
              (pprint-indent :block 4)
              (pprint-newline :mandatory)
              (loop while (and 2block (eq (ir2-block-block 2block) block))
                 do (print-ir2-block 2block)
                 do (setq 2block (ir2-block-next 2block))))
         do (pprint-newline :mandatory))))
  (values))

;;; Do a PRINT-NODES on BLOCK and all blocks reachable from it by
;;; successor links.
(defun print-blocks (block)
  (setq block (block-or-lose block))
  (do-blocks (block (block-component block) :both)
    (setf (block-flag block) nil))
  (labels ((walk (block)
	     (unless (block-flag block)
	       (setf (block-flag block) t)
	       (when (block-start block)
		 (print-nodes block))
	       (dolist (block (block-succ block))
		 (walk block)))))
    (walk block))
  (values))

;;; Print all blocks in BLOCK's component in DFO.
(defun print-all-blocks (thing)
  (do-blocks (block (block-component (block-or-lose thing)))
    (handler-case (print-nodes block)
      (error (condition)
	(format t "~&~A...~%" condition))))
  (values))

(defvar *list-conflicts-table* (make-hash-table :test 'eq))

;;; Add all ALWAYS-LIVE TNs in BLOCK to the conflicts. TN is ignored
;;; when it appears in the global conflicts.
(defun add-always-live-tns (block tn)
  (declare (type ir2-block block) (type tn tn))
  (do ((conf (ir2-block-global-tns block)
	     (global-conflicts-next-blockwise conf)))
      ((null conf))
    (when (eq (global-conflicts-kind conf) :live)
      (let ((btn (global-conflicts-tn conf)))
	(unless (eq btn tn)
	  (setf (gethash btn *list-conflicts-table*) t)))))
  (values))

;;; Add all local TNs in BLOCK to the conflicts.
(defun add-all-local-tns (block)
  (declare (type ir2-block block))
  (let ((ltns (ir2-block-local-tns block)))
    (dotimes (i (ir2-block-local-tn-count block))
      (setf (gethash (svref ltns i) *list-conflicts-table*) t)))
  (values))

;;; Make a list out of all of the recorded conflicts.
(defun listify-conflicts-table ()
  (collect ((res))
    (maphash (lambda (k v)
	       (declare (ignore v))
	       (when k
		 (res k)))
	     *list-conflicts-table*)
    (clrhash *list-conflicts-table*)
    (res)))

;;; Return a list of a the TNs that conflict with TN. Sort of, kind
;;; of. For debugging use only. Probably doesn't work on :COMPONENT TNs.
(defun list-conflicts (tn)
  (aver (member (tn-kind tn) '(:normal :environment :debug-environment)))
  (let ((confs (tn-global-conflicts tn)))
    (cond (confs
	   (clrhash *list-conflicts-table*)
	   (do ((conf confs (global-conflicts-next-tnwise conf)))
	       ((null conf))
             (format t "~&#<block ~D kind ~S>~%"
                     (block-number (ir2-block-block (global-conflicts-block
						     conf)))
                     (global-conflicts-kind conf))
	     (let ((block (global-conflicts-block conf)))
	       (add-always-live-tns block tn)
	       (if (eq (global-conflicts-kind conf) :live)
		   (add-all-local-tns block)
		   (let ((bconf (global-conflicts-conflicts conf))
			 (ltns (ir2-block-local-tns block)))
		     (dotimes (i (ir2-block-local-tn-count block))
		       (when (/= (sbit bconf i) 0)
			 (setf (gethash (svref ltns i) *list-conflicts-table*)
			       t)))))))
	   (listify-conflicts-table))
	  (t
	   (let* ((block (tn-local tn))
		  (ltns (ir2-block-local-tns block))
		  (confs (tn-local-conflicts tn)))
	     (collect ((res))
	       (dotimes (i (ir2-block-local-tn-count block))
		 (when (/= (sbit confs i) 0)
		   (let ((tn (svref ltns i)))
		     (when (and tn (not (eq tn :more))
				(not (tn-global-conflicts tn)))
		       (res tn)))))
	       (do ((gtn (ir2-block-global-tns block)
			 (global-conflicts-next-blockwise gtn)))
		   ((null gtn))
		 (when (or (eq (global-conflicts-kind gtn) :live)
			   (/= (sbit confs (global-conflicts-number gtn)) 0))
		   (res (global-conflicts-tn gtn))))
	       (res)))))))

(defun nth-vop (thing n)
  #!+sb-doc
  "Return the Nth VOP in the IR2-BLOCK pointed to by THING."
  (let ((block (block-info (block-or-lose thing))))
    (do ((i 0 (1+ i))
	 (vop (ir2-block-start-vop block) (vop-next vop)))
	((= i n) vop))))