src/compiler/ir1final.lisp

   1 ;;;; This file implements the IR1 finalize phase, which checks for
   2 ;;;; various semantic errors.
   3
   4 ;;;; This software is part of the SBCL system. See the README file for
   5 ;;;; more information.
   6 ;;;;
   7 ;;;; This software is derived from the CMU CL system, which was
   8 ;;;; written at Carnegie Mellon University and released into the
   9 ;;;; public domain. The software is in the public domain and is
  10 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
  11 ;;;; files for more information.
  12
  13 (in-package "SB!C")
  14
  15 ;;; Give the user grief about optimizations that we weren't able to
  16 ;;; do. It is assumed that the user wants to hear about this, or there
  17 ;;; wouldn't be any entries in the table. If the node has been deleted
  18 ;;; or is no longer a known call, then do nothing; some other
  19 ;;; optimization must have gotten to it.
  20 (defun note-failed-optimization (node failures)
  21   (declare (type combination node) (list failures))
  22   (unless (or (node-deleted node)
  23               (not (eq :known (combination-kind node))))
  24     (let ((*compiler-error-context* node))
  25       (dolist (failure failures)
  26         (let ((what (cdr failure))
  27               (note (transform-note (car failure))))
  28           (cond
  29            ((consp what)
  30             (compiler-notify "~@<unable to ~2I~_~A ~I~_because: ~2I~_~?~:>"
  31                              note (first what) (rest what)))
  32            ((valid-fun-use node what
  33                            :argument-test #'types-equal-or-intersect
  34                            :result-test #'values-types-equal-or-intersect)
  35             (collect ((messages))
  36               (flet ((give-grief (string &rest stuff)
  37                        (messages string)
  38                        (messages stuff)))
  39                 (valid-fun-use node what
  40                                :unwinnage-fun #'give-grief
  41                                :lossage-fun #'give-grief))
  42               (compiler-notify "~@<unable to ~
  43                                 ~2I~_~A ~
  44                                 ~I~_due to type uncertainty: ~
  45                                 ~2I~_~{~?~^~@:_~}~:>"
  46                              note (messages))))
  47            ;; As best I can guess, it's OK to fall off the end here
  48            ;; because if it's not a VALID-FUNCTION-USE, the user
  49            ;; doesn't want to hear about it. The things I caught when
  50            ;; I put ERROR "internal error: unexpected FAILURE=~S" here
  51            ;; didn't look like things we need to report. -- WHN 2001-02-07
  52            ))))))
  53
  54 ;;; For each named function with an XEP, note the definition of that
  55 ;;; name, and add derived type information to the INFO environment. We
  56 ;;; also delete the FUNCTIONAL from *FREE-FUNS* to eliminate the
  57 ;;; possibility that new references might be converted to it.
  58 (defun finalize-xep-definition (fun)
  59   (let* ((leaf (functional-entry-fun fun))
  60          (defined-ftype (definition-type leaf)))
  61     (setf (leaf-type leaf) defined-ftype)
  62     (when (and (leaf-has-source-name-p leaf)
  63                (eq (leaf-source-name leaf) (functional-debug-name leaf)))
  64       (let ((source-name (leaf-source-name leaf)))
  65         (let* ((where (info :function :where-from source-name))
  66                (*compiler-error-context* (lambda-bind (main-entry leaf)))
  67                (global-def (gethash source-name *free-funs*))
  68                (global-p (defined-fun-p global-def)))
  69           (note-name-defined source-name :function)
  70           (when global-p
  71             (remhash source-name *free-funs*))
  72           (ecase where
  73             (:assumed
  74              (let ((approx-type (info :function :assumed-type source-name)))
  75                (when (and approx-type (fun-type-p defined-ftype))
  76                  (valid-approximate-type approx-type defined-ftype))
  77                ;; globaldb can't enforce invariants such as :assumed-type and
  78                ;; :type being mutually exclusive. For that reason it would have
  79                ;; made sense to use a single info-type holding either a true
  80                ;; function type or an approximate-fun-type. Regardless, it is
  81                ;; slightly preferable to clear the old before setting the new.
  82                (clear-info :function :assumed-type source-name)
  83                (setf (info :function :type source-name) defined-ftype))
  84              (setf (info :function :where-from source-name) :defined))
  85             ((:declared :defined-method)
  86              (let ((declared-ftype (proclaimed-ftype source-name)))
  87                (unless (defined-ftype-matches-declared-ftype-p
  88                          defined-ftype declared-ftype)
  89                  (compiler-style-warn
  90                   "~@<The previously declared FTYPE~2I ~_~S~I ~_~
  91                    conflicts with the definition type ~2I~_~S~:>"
  92                   (type-specifier declared-ftype)
  93                   (type-specifier defined-ftype)))))
  94             (:defined
  95              (setf (info :function :type source-name) defined-ftype)))))))
  96   (values))
  97
  98 ;;; Find all calls in COMPONENT to assumed functions and update the
  99 ;;; assumed type information. This is delayed until now so that we
 100 ;;; have the best possible information about the actual argument
 101 ;;; types.
 102 (defun note-assumed-types (component name var)
 103   (when (and (eq (leaf-where-from var) :assumed)
 104              (not (and (defined-fun-p var)
 105                        (eq (defined-fun-inlinep var) :notinline)))
 106              (eq (info :function :where-from name) :assumed)
 107              (eq (info :function :kind name) :function))
 108     (let ((atype (info :function :assumed-type name)))
 109       (dolist (ref (leaf-refs var))
 110         (let ((dest (node-dest ref)))
 111           (when (and (eq (node-component ref) component)
 112                      (combination-p dest)
 113                      (eq (lvar-uses (basic-combination-fun dest)) ref))
 114             (setq atype (note-fun-use dest atype)))))
 115       (setf (info :function :assumed-type name) atype))))
 116
 117 ;;; Merge CASTs with preceding/following nodes.
 118 (defun ir1-merge-casts (component)
 119   (do-blocks-backwards (block component)
 120     (do-nodes-backwards (node lvar block)
 121       (let ((dest (when lvar (lvar-dest lvar))))
 122         (cond ((and (cast-p dest)
 123                     (not (cast-type-check dest))
 124                     (immediately-used-p lvar node))
 125                (let ((dtype (node-derived-type node))
 126                      (atype (node-derived-type dest)))
 127                  (when (values-types-equal-or-intersect
 128                         dtype atype)
 129                    ;; FIXME: We do not perform pathwise CAST->type-error
 130                    ;; conversion, and type errors can later cause
 131                    ;; backend failures. On the other hand, this version
 132                    ;; produces less efficient code.
 133                    ;;
 134                    ;; This is sorta DERIVE-NODE-TYPE, but does not try
 135                    ;; to optimize the node.
 136                    (setf (node-derived-type node)
 137                          (values-type-intersection dtype atype)))))
 138               ((and (cast-p node)
 139                     (eq (cast-type-check node) :external))
 140                (aver (basic-combination-p dest))
 141                (delete-filter node lvar (cast-value node))))))))
 142
 143 ;;; Do miscellaneous things that we want to do once all optimization
 144 ;;; has been done:
 145 ;;;  -- Record the derived result type before the back-end trashes the
 146 ;;;     flow graph.
 147 ;;;  -- Note definition of any entry points.
 148 ;;;  -- Note any failed optimizations.
 149 (defun ir1-finalize (component)
 150   (declare (type component component))
 151   (dolist (fun (component-lambdas component))
 152     (case (functional-kind fun)
 153       (:external
 154        (finalize-xep-definition fun))
 155       ((nil :toplevel)
 156        (setf (leaf-type fun) (definition-type fun)))))
 157
 158   (maphash #'note-failed-optimization
 159            (component-failed-optimizations component))
 160
 161   (maphash (lambda (k v)
 162              (note-assumed-types component k v))
 163            *free-funs*)
 164
 165   (ir1-merge-casts component)
 166
 167   (values))