X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcode%2Fsysmacs.lisp;h=60f18d751abd861436e9f5bd1eea2a7696548106;hb=ee222567ee95eaac8f6f4c877242dd116bfb8337;hp=67e29ddefcdccbb24b862f5d29304ce70e63f588;hpb=1f724b3d4ea331dd05ace51a27a033831d83c85d;p=sbcl.git diff --git a/src/code/sysmacs.lisp b/src/code/sysmacs.lisp index 67e29dd..60f18d7 100644 --- a/src/code/sysmacs.lisp +++ b/src/code/sysmacs.lisp @@ -19,21 +19,59 @@ (declare (optimize (safety 0) (speed 3))) (sb!vm::locked-symbol-global-value-add ',symbol-name ,delta))) -;;; When >0, inhibits garbage collection. -(declaim (type index *gc-inhibit*)) (defvar *gc-inhibit*) ; initialized in cold init -(defmacro without-gcing (&rest body) +;;; When the dynamic usage increases beyond this amount, the system +;;; notes that a garbage collection needs to occur by setting +;;; *GC-PENDING* to T. It starts out as NIL meaning nobody has figured +;;; out what it should be yet. +(defvar *gc-pending* nil) + +#!+sb-thread +(defvar *stop-for-gc-pending* nil) + +(defmacro without-gcing (&body body) #!+sb-doc - "Executes the forms in the body without doing a garbage collection." - `(unwind-protect - (progn - (atomic-incf/symbol *gc-inhibit*) - ,@body) - (atomic-incf/symbol *gc-inhibit* -1) - (when (and *need-to-collect-garbage* (zerop *gc-inhibit*)) - (sub-gc)))) + "Executes the forms in the body without doing a garbage collection. It +inhibits both automatically and explicitly triggered collections. Finally, +upon leaving the BODY if gc is not inhibited it runs the pending gc. +Similarly, if gc is triggered in another thread then it waits until gc is +enabled in this thread. +Implies SB-SYS:WITHOUT-INTERRUPTS for BODY, and causes any nested +SB-SYS:WITH-INTERRUPTS to signal a warning during execution of the BODY. + +Should be used with great care, and not at all in multithreaded application +code: Any locks that are ever acquired while GC is inhibited need to be always +held with GC inhibited to prevent deadlocks: if T1 holds the lock and is +stopped for GC while T2 is waiting for the lock inside WITHOUT-GCING the +system will be deadlocked. Since SBCL does not currently document its internal +locks, application code can never be certain that this invariant is +maintained." + (with-unique-names (without-gcing-body) + `(flet ((,without-gcing-body () + ,@body)) + (if *gc-inhibit* + (,without-gcing-body) + (without-interrupts + ;; We need to disable interrupts before disabling GC, so that + ;; signal handlers using locks don't accidentally try to grab + ;; them with GC inhibited. + ;; + ;; It would be nice to implement this with just a single UWP, but + ;; unfortunately it seems that it cannot be done: the naive + ;; solution of binding both *INTERRUPTS-ENABLED* and + ;; *GC-INHIBIT*, and checking for both pending GC and interrupts + ;; in the cleanup breaks if we have a GC pending, but no + ;; interrupts, and we receive an asynch unwind while checking for + ;; the pending GC: we unwind before handling the pending GC, and + ;; will be left running with further GCs blocked due to the GC + ;; pending flag. + (unwind-protect + (let ((*gc-inhibit* t)) + (,without-gcing-body)) + (when (or *gc-pending* #!+sb-thread *stop-for-gc-pending*) + (sb!unix::receive-pending-interrupt)))))))) ;;; EOF-OR-LOSE is a useful macro that handles EOF. (defmacro eof-or-lose (stream eof-error-p eof-value) @@ -49,30 +87,30 @@ (let ((svar (gensym))) `(let ((,svar ,stream)) (cond ((null ,svar) *standard-input*) - ((eq ,svar t) *terminal-io*) - (T ,@(when check-type `((enforce-type ,svar ,check-type))) - #!+high-security - (unless (input-stream-p ,svar) - (error 'simple-type-error - :datum ,svar - :expected-type '(satisfies input-stream-p) - :format-control "~S isn't an input stream" - :format-arguments (list ,svar))) - ,svar))))) + ((eq ,svar t) *terminal-io*) + (t ,@(when check-type `((enforce-type ,svar ,check-type))) ; + #!+high-security + (unless (input-stream-p ,svar) + (error 'simple-type-error + :datum ,svar + :expected-type '(satisfies input-stream-p) + :format-control "~S isn't an input stream" + :format-arguments (list ,svar))) + ,svar))))) (defmacro out-synonym-of (stream &optional check-type) (let ((svar (gensym))) `(let ((,svar ,stream)) (cond ((null ,svar) *standard-output*) - ((eq ,svar t) *terminal-io*) - (T ,@(when check-type `((check-type ,svar ,check-type))) - #!+high-security - (unless (output-stream-p ,svar) - (error 'simple-type-error - :datum ,svar - :expected-type '(satisfies output-stream-p) - :format-control "~S isn't an output stream." - :format-arguments (list ,svar))) - ,svar))))) + ((eq ,svar t) *terminal-io*) + (t ,@(when check-type `((check-type ,svar ,check-type))) + #!+high-security + (unless (output-stream-p ,svar) + (error 'simple-type-error + :datum ,svar + :expected-type '(satisfies output-stream-p) + :format-control "~S isn't an output stream." + :format-arguments (list ,svar))) + ,svar))))) ;;; WITH-mumble-STREAM calls the function in the given SLOT of the ;;; STREAM with the ARGS for ANSI-STREAMs, or the FUNCTION with the @@ -80,35 +118,43 @@ (defmacro with-in-stream (stream (slot &rest args) &optional stream-dispatch) `(let ((stream (in-synonym-of ,stream))) ,(if stream-dispatch - `(if (ansi-stream-p stream) - (funcall (,slot stream) stream ,@args) - ,@(when stream-dispatch - `(,(destructuring-bind (function &rest args) stream-dispatch - `(,function stream ,@args))))) - `(funcall (,slot stream) stream ,@args)))) + `(if (ansi-stream-p stream) + (funcall (,slot stream) stream ,@args) + ,@(when stream-dispatch + `(,(destructuring-bind (function &rest args) stream-dispatch + `(,function stream ,@args))))) + `(funcall (,slot stream) stream ,@args)))) -(defmacro with-out-stream (stream (slot &rest args) &optional stream-dispatch) - `(let ((stream (out-synonym-of ,stream))) +(defmacro with-out-stream/no-synonym (stream (slot &rest args) &optional stream-dispatch) + `(let ((stream ,stream)) ,(if stream-dispatch - `(if (ansi-stream-p stream) - (funcall (,slot stream) stream ,@args) - ,@(when stream-dispatch - `(,(destructuring-bind (function &rest args) stream-dispatch - `(,function stream ,@args))))) - `(funcall (,slot stream) stream ,@args)))) + `(if (ansi-stream-p stream) + (funcall (,slot stream) stream ,@args) + ,@(when stream-dispatch + `(,(destructuring-bind (function &rest args) stream-dispatch + `(,function stream ,@args))))) + `(funcall (,slot stream) stream ,@args)))) + +(defmacro with-out-stream (stream (slot &rest args) &optional stream-dispatch) + `(with-out-stream/no-synonym (out-synonym-of ,stream) + (,slot ,@args) ,stream-dispatch)) + ;;;; These are hacks to make the reader win. ;;; This macro sets up some local vars for use by the ;;; FAST-READ-CHAR macro within the enclosed lexical scope. The stream ;;; is assumed to be a ANSI-STREAM. +;;; +;;; KLUDGE: Some functions (e.g. ANSI-STREAM-READ-LINE) use these variables +;;; directly, instead of indirecting through FAST-READ-CHAR. (defmacro prepare-for-fast-read-char (stream &body forms) `(let* ((%frc-stream% ,stream) - (%frc-method% (ansi-stream-in %frc-stream%)) - (%frc-buffer% (ansi-stream-cin-buffer %frc-stream%)) - (%frc-index% (ansi-stream-in-index %frc-stream%))) + (%frc-method% (ansi-stream-in %frc-stream%)) + (%frc-buffer% (ansi-stream-cin-buffer %frc-stream%)) + (%frc-index% (ansi-stream-in-index %frc-stream%))) (declare (type index %frc-index%) - (type ansi-stream %frc-stream%)) + (type ansi-stream %frc-stream%)) ,@forms)) ;;; This macro must be called after one is done with FAST-READ-CHAR @@ -117,17 +163,22 @@ `(setf (ansi-stream-in-index %frc-stream%) %frc-index%)) ;;; a macro with the same calling convention as READ-CHAR, to be used -;;; within the scope of a PREPARE-FOR-FAST-READ-CHAR +;;; within the scope of a PREPARE-FOR-FAST-READ-CHAR. (defmacro fast-read-char (&optional (eof-error-p t) (eof-value ())) `(cond - ((not %frc-buffer%) - (funcall %frc-method% %frc-stream% ,eof-error-p ,eof-value)) - ((= %frc-index% +ansi-stream-in-buffer-length+) - (prog1 (fast-read-char-refill %frc-stream% ,eof-error-p ,eof-value) - (setq %frc-index% (ansi-stream-in-index %frc-stream%)))) - (t - (prog1 (aref %frc-buffer% %frc-index%) - (incf %frc-index%))))) + ((not %frc-buffer%) + (funcall %frc-method% %frc-stream% ,eof-error-p ,eof-value)) + ((= %frc-index% +ansi-stream-in-buffer-length+) + (multiple-value-bind (eof-p index-or-value) + (fast-read-char-refill %frc-stream% ,eof-error-p ,eof-value) + (if eof-p + index-or-value + (progn + (setq %frc-index% (1+ index-or-value)) + (aref %frc-buffer% index-or-value))))) + (t + (prog1 (aref %frc-buffer% %frc-index%) + (incf %frc-index%))))) ;;;; And these for the fasloader... @@ -143,11 +194,11 @@ ;;; for the FAST-READ-CHAR stuff) -- WHN 19990825 (defmacro prepare-for-fast-read-byte (stream &body forms) `(let* ((%frc-stream% ,stream) - (%frc-method% (ansi-stream-bin %frc-stream%)) - (%frc-buffer% (ansi-stream-in-buffer %frc-stream%)) - (%frc-index% (ansi-stream-in-index %frc-stream%))) + (%frc-method% (ansi-stream-bin %frc-stream%)) + (%frc-buffer% (ansi-stream-in-buffer %frc-stream%)) + (%frc-index% (ansi-stream-in-index %frc-stream%))) (declare (type index %frc-index%) - (type ansi-stream %frc-stream%)) + (type ansi-stream %frc-stream%)) ,@forms)) ;;; Similar to fast-read-char, but we use a different refill routine & don't @@ -162,9 +213,9 @@ (funcall %frc-method% %frc-stream% ,eof-error-p ,eof-value)) ((= %frc-index% +ansi-stream-in-buffer-length+) (prog1 (fast-read-byte-refill %frc-stream% ,eof-error-p ,eof-value) - (setq %frc-index% (ansi-stream-in-index %frc-stream%)))) + (setq %frc-index% (ansi-stream-in-index %frc-stream%)))) (t (prog1 (aref %frc-buffer% %frc-index%) - (incf %frc-index%)))))) + (incf %frc-index%)))))) (defmacro done-with-fast-read-byte () `(done-with-fast-read-char))