[cmucl-commit] [git] CMU Common Lisp branch master updated. snapshot-2013-01-20-g0174bfe

[Raymond Toy]

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- Log -----------------------------------------------------------------
commit 0174bfebdb2ed8edbdf5b3dade4fd64965d4a9f4
Author: Raymond Toy <toy.raymond at gmail.com>
Date:   Thu Jan 31 21:27:36 2013 -0800

    Fix ticket:72 : SIGFPE with no exceptions enabled
    
     code/float-trap.lisp::
      * In the default case, check FOP to see if it's defined.  This means
        it's a divide exception.
    
     code/x86-vm.lisp::
      * Also check to see if the offending instruction is a DIV or IDIV,
        which means we got an integer overflow.  Return the appropriate
        values in this case.

diff --git a/src/code/float-trap.lisp b/src/code/float-trap.lisp
index 6616146..d7bab6f 100644
--- a/src/code/float-trap.lisp
+++ b/src/code/float-trap.lisp
@@ -239,7 +239,7 @@
 ;;;    Signal the appropriate condition when we get a floating-point error.
 ;;;
 (defun sigfpe-handler (signal code scp)
-  (declare (ignore signal code)
+  (declare (ignore signal)
 	   (type system-area-pointer scp))
   (let* ((modes (sigcontext-floating-point-modes
 		 (alien:sap-alien scp (* unix:sigcontext))))
@@ -313,9 +313,26 @@
 	     ;; operands also seem to be missing.  Signal a general
 	     ;; arithmetic error.
 	     #+(and x86 solaris)
-	     (error 'arithmetic-error :operands operands)
+	     (error _"SIGFPE with no exceptions currently enabled? (si-code = ~D)"
+		    code)
+	     ;; For all other x86 ports, we should only get here if
+	     ;; the SIGFPE was caused by an integer overflow on
+	     ;; division.  For sparc and ppc, I (rtoy) don't think
+	     ;; there's any other way to get here since integer
+	     ;; overflows aren't signaled.
+	     ;;
+	     ;; In that case, FOP should be /, so we can generate a
+	     ;; nice arithmetic-error.  It's possible to use CODE,
+	     ;; which is supposed to indicate what caused the
+	     ;; exception, but each OS is different, so we don't; FOP
+	     ;; can tell us.
 	     #-(and x86 solaris)
-	     (error _"SIGFPE with no exceptions currently enabled?"))))))
+	     (if fop
+		 (error 'arithmetic-error
+			:operation fop
+			:operands operands)
+		 (error _"SIGFPE with no exceptions currently enabled? (si-code = ~D"
+			code)))))))
 
 ;;; WITH-FLOAT-TRAPS-MASKED  --  Public
 ;;;
diff --git a/src/code/x86-vm.lisp b/src/code/x86-vm.lisp
index 19211ed..961dacb 100644
--- a/src/code/x86-vm.lisp
+++ b/src/code/x86-vm.lisp
@@ -539,9 +539,11 @@
 
 (defun get-fp-operation (scp)
   (declare (type (alien (* sigcontext)) scp))
-  ;; Get the offending FP instruction from the context.  We return the
-  ;; operation associated with the FP instruction, the precision of
-  ;; the operation, and the operands of the instruction.
+  ;; Get the instruction that caused the SIGFPE from the context.  The
+  ;; SIGFPE can be caused by either a floating-point operation or an
+  ;; integer division (overflow).  We return the operation associated
+  ;; with the instruction, and the the operands of the instruction, if
+  ;; possible.
 
   ;; For SSE2, the PC should be at the offending SSE2 instruction
   (let ((pc (sigcontext-program-counter scp)))
@@ -580,9 +582,10 @@
 		     (when (= mod #b11)
 		       (sigcontext-float-register scp (+ 8 r/m) format))))))
       ;; Look at the instruction and see if it's one of the arithmetic
-      ;; SSE2 instructions.  If so, figure out the operation and try
-      ;; to get the operands.  Currently, if an operand is in memory,
-      ;; we don't try to fetch it.
+      ;; SSE2 instructions or an integer division instruction.  If so,
+      ;; figure out the operation and try to get the operands.
+      ;; Currently, if an operand is in memory, we don't try to fetch
+      ;; it.
       ;;
       ;; Also, for the packed operations that hold complex numbers,
       ;; it's not exactly clear what to do.  The main issue is that
@@ -644,8 +647,38 @@
 		       (when src
 			 (list (realpart src)
 			       (imagpart src))))))
+	    ((or (= (sys:sap-ref-8 pc 0) #xf7))
+	     ;; DIV or IDIV.  We don't support 8-bit division
+	     (multiple-value-bind (mod r/m v)
+		 (decode-mod-r/m (sys:sap-ref-8 pc 1))
+	       #+(or)
+	       (format t "DIV: #X~X: mod, r/m v = ~X ~X ~X~%"
+		       (sys:sap-ref-8 pc 0)
+		       mod r/m v)
+	       ;; r/m tells us the divisor reg
+	       (flet ((maybe-adjust-sign (x 64bit-p)
+			;; Maybe convert unsigned integer X to a
+			;; signed integer.  64BIT-P is set if X is
+			;; supposed to be a 64-bit integer.
+			(if (= v 7)
+			    (- x (if 64bit-p
+				     #x10000000000000000
+				     #x100000000))
+			    x)))
+		 ;; For the div instructions, the dividend is always
+		 ;; in EDX:EAX
+		 (let ((dividend (maybe-adjust-sign
+				  (+ (ash (sigcontext-register scp 4) 32)
+				     (sigcontext-register scp 0))
+				  t))
+		       (divisor (maybe-adjust-sign
+				 (sigcontext-register scp (ash r/m 1))
+				 nil)))
+		   (values '/
+			   dividend
+			   divisor)))))
 	    (t
-	     (values nil nil nil nil))))))
+	     (values nil nil nil))))))
 
 (defun get-fp-operands (scp modes)
   (declare (type (alien (* sigcontext)) scp)

-----------------------------------------------------------------------

Summary of changes:
 src/code/float-trap.lisp |   23 +++++++++++++++++++--
 src/code/x86-vm.lisp     |   47 +++++++++++++++++++++++++++++++++++++++------
 2 files changed, 60 insertions(+), 10 deletions(-)


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