Excise the stupid fucking `set-*` opcodes
The book uses the horribly-confusingly-named `set-*` operations for handling
subterms in query mode. The author does this because he claims this is both
easier to understand and more performant. In reality it is neither of these
things.
If you just name the subterm-handling opcodes something not completely stupid,
like `handle-subterm-*` instead of `unify-*` it becomes obvious what they do.
Also, despite the fact that `put-*` instructions now need to set the WAM's
`mode`, we still get about a 10% speedup here, likely from some combination of
reducing the VM loop code size and simplifying the compilation process. So it's
not even more performant.
TL;DR: Just say "No" to `set-*`.
| author |
Steve Losh <steve@stevelosh.com> |
| date |
Sun, 10 Jul 2016 14:21:18 +0000 |
| parents |
92c590f78133 |
| children |
8cd3257c58e3 |
(in-package #:bones.wam)
(defun registers-pointing-to (wam addr)
(loop
:for r :from 0 :below +register-count+
:for reg = (wam-local-register wam r)
:when (= reg addr)
:collect r))
(defun heap-debug (wam addr cell indent-p)
(format
nil "~A~A~{<-X~A ~}"
(if indent-p
" "
"")
(switch ((cell-type cell))
(+tag-reference+
(if (= addr (cell-value cell))
"unbound variable "
(format nil "var pointer to ~4,'0X " (cell-value cell))))
(+tag-structure+
(format nil "structure pointer to ~4,'0X " (cell-value cell)))
(+tag-functor+
(destructuring-bind (functor . arity)
(wam-functor-lookup wam (cell-value cell))
(format nil "~A/~D " functor arity)))
(+tag-constant+
(format nil "~A/0 " (wam-functor-symbol wam (cell-value cell))))
(t ""))
(registers-pointing-to wam addr)))
(defun dump-heap (wam from to highlight)
;; This code is awful, sorry.
(let ((store (wam-store wam)))
(format t "HEAP~%")
(format t " +------+-----+----------+--------------------------------------+~%")
(format t " | ADDR | TYP | VALUE | DEBUG |~%")
(format t " +------+-----+----------+--------------------------------------+~%")
(when (> from +heap-start+)
(format t " | ⋮ | ⋮ | ⋮ | |~%"))
(flet ((print-cell (i cell indent)
(let ((hi (= i highlight)))
(format t "~A ~4,'0X | ~A | ~8,'0X | ~36A ~A~%"
(if hi "==>" " |")
i
(cell-type-short-name cell)
(cell-value cell)
(heap-debug wam i cell (> indent 0))
(if hi "<===" "|")))))
(loop :for i :from from :below to
:with indent = 0
:for cell = (aref store i)
:do
(progn
(print-cell i cell indent)
(if (cell-functor-p cell)
(setf indent (wam-functor-arity wam (cell-value cell)))
(when (not (zerop indent))
(decf indent))))))
(when (< to (wam-heap-pointer wam))
(format t " | ⋮ | ⋮ | ⋮ | |~%"))
(format t " +------+-----+----------+--------------------------------------+~%")
(values)))
(defun dump-stack (wam)
(format t "STACK~%")
(format t " +------+----------+-------------------------------+~%")
(format t " | ADDR | VALUE | |~%")
(format t " +------+----------+-------------------------------+~%")
(with-accessors ((e wam-environment-pointer)
(b wam-backtrack-pointer))
wam
(when (not (= +stack-start+ e b))
(loop
:with nargs = nil
:with arg = 0
:with currently-in = nil
:for addr :from (1+ +stack-start+) :below (wam-stack-top wam)
:for cell = (wam-stack-word wam addr)
:for offset = 0 :then (1+ offset)
:do
(when (not (zerop addr))
(switch (addr :test #'=)
(e (setf currently-in :frame offset 0 arg 0))
(b (setf currently-in :choice offset 0 arg 0))))
(format t " | ~4,'0X | ~8,'0X | ~30A|~A~A~%"
addr
cell
(case currently-in ; jesus christ this needs to get fixed
(:frame
(cond
((= addr +stack-start+) "")
((= offset 0) "CE ===========================")
((= offset 1) "CP")
((= offset 2) "CUT")
((= offset 3)
(if (zerop cell)
(progn
(setf currently-in nil)
"N: EMPTY")
(progn
(setf nargs cell)
(format nil "N: ~D" cell))))
((< arg nargs)
(prog1
(format nil " Y~D: ~8,'0X ~A"
arg cell (cell-aesthetic cell))
(when (= nargs (incf arg))
(setf currently-in nil))))))
(:choice ; sweet lord make it stop
(cond
((= addr +stack-start+) "")
((= offset 0)
(if (zerop cell)
(progn
(setf currently-in nil)
"N: EMPTY =================")
(progn
(setf nargs cell)
(format nil "N: ~D =============" cell))))
((= offset 1) "CE saved env pointer")
((= offset 2) "CP saved cont pointer")
((= offset 3) "CB previous choice")
((= offset 4) "BP next clause")
((= offset 5) "TR saved trail pointer")
((= offset 6) "H saved heap pointer")
((< arg nargs)
(prog1
(format nil " A~D: ~8,'0X ~A"
arg cell (cell-aesthetic cell))
(when (= nargs (incf arg))
(setf currently-in nil))))))
(t ""))
(if (= addr e) " <- E" "")
(if (= addr b) " <- B" "")))))
(format t " +------+----------+-------------------------------+~%"))
(defun pretty-functor (functor-index functor-list)
(when functor-list
(destructuring-bind (symbol . arity)
(elt functor-list functor-index)
(format nil "~A/~D" symbol arity))))
(defun pretty-arguments (arguments)
(format nil "~{ ~4,'0X~}" arguments))
(defgeneric instruction-details (opcode arguments functor-list))
(defmethod instruction-details ((opcode t) arguments functor-list)
(format nil "~A~A"
(opcode-short-name opcode)
(pretty-arguments arguments)))
(defmethod instruction-details ((opcode (eql +opcode-get-structure+)) arguments functor-list)
(format nil "GETS~A ; X~A = ~A"
(pretty-arguments arguments)
(second arguments)
(pretty-functor (first arguments) functor-list)))
(defmethod instruction-details ((opcode (eql +opcode-put-structure+)) arguments functor-list)
(format nil "PUTS~A ; X~A <- new ~A"
(pretty-arguments arguments)
(second arguments)
(pretty-functor (first arguments) functor-list)))
(defmethod instruction-details ((opcode (eql +opcode-get-variable-local+)) arguments functor-list)
(format nil "GVAR~A ; X~A <- A~A"
(pretty-arguments arguments)
(first arguments)
(second arguments)))
(defmethod instruction-details ((opcode (eql +opcode-get-variable-stack+)) arguments functor-list)
(format nil "GVAR~A ; Y~A <- A~A"
(pretty-arguments arguments)
(first arguments)
(second arguments)))
(defmethod instruction-details ((opcode (eql +opcode-get-value-local+)) arguments functor-list)
(format nil "GVLU~A ; X~A = A~A"
(pretty-arguments arguments)
(first arguments)
(second arguments)))
(defmethod instruction-details ((opcode (eql +opcode-get-value-stack+)) arguments functor-list)
(format nil "GVLU~A ; Y~A = A~A"
(pretty-arguments arguments)
(first arguments)
(second arguments)))
(defmethod instruction-details ((opcode (eql +opcode-put-variable-local+)) arguments functor-list)
(format nil "PVAR~A ; X~A <- A~A <- new unbound REF"
(pretty-arguments arguments)
(first arguments)
(second arguments)))
(defmethod instruction-details ((opcode (eql +opcode-put-variable-stack+)) arguments functor-list)
(format nil "PVAR~A ; Y~A <- A~A <- new unbound REF"
(pretty-arguments arguments)
(first arguments)
(second arguments)))
(defmethod instruction-details ((opcode (eql +opcode-put-value-local+)) arguments functor-list)
(format nil "PVLU~A ; A~A <- X~A"
(pretty-arguments arguments)
(second arguments)
(first arguments)))
(defmethod instruction-details ((opcode (eql +opcode-put-value-stack+)) arguments functor-list)
(format nil "PVLU~A ; A~A <- Y~A"
(pretty-arguments arguments)
(second arguments)
(first arguments)))
(defmethod instruction-details ((opcode (eql +opcode-call+)) arguments functor-list)
(format nil "CALL~A ; ~A"
(pretty-arguments arguments)
(pretty-functor (first arguments) functor-list)))
(defmethod instruction-details ((opcode (eql +opcode-get-constant+)) arguments functor-list)
(format nil "GCON~A ; X~A = CONSTANT ~A"
(pretty-arguments arguments)
(second arguments)
(pretty-functor (first arguments) functor-list)))
(defmethod instruction-details ((opcode (eql +opcode-put-constant+)) arguments functor-list)
(format nil "PCON~A ; X~A <- CONSTANT ~A"
(pretty-arguments arguments)
(second arguments)
(pretty-functor (first arguments) functor-list)))
(defmethod instruction-details ((opcode (eql +opcode-unify-constant+)) arguments functor-list)
(format nil "UCON~A ; UNIFY CONSTANT ~A"
(pretty-arguments arguments)
(pretty-functor (first arguments) functor-list)))
(defmethod instruction-details ((opcode (eql +opcode-get-list+)) arguments functor-list)
(format nil "GLST~A ; X~A = [vvv | vvv]"
(pretty-arguments arguments)
(first arguments)))
(defmethod instruction-details ((opcode (eql +opcode-put-list+)) arguments functor-list)
(format nil "PLST~A ; X~A = [vvv | vvv]"
(pretty-arguments arguments)
(first arguments)))
(defun dump-code-store (wam code-store
&optional
(from 0)
(to (length code-store)))
;; This is a little trickier than might be expected. We have to walk from
;; address 0 no matter what `from` we get, because instruction sizes vary and
;; aren't aligned. So if we just start at `from` we might start in the middle
;; of an instruction and everything would be fucked.
(let ((addr 0)
(lbls (bones.utils::invert-hash-table (wam-code-labels wam)))) ; oh god
(while (< addr to)
(let ((instruction (retrieve-instruction code-store addr)))
(when (>= addr from)
(let ((lbl (gethash addr lbls))) ; forgive me
(when lbl
(format t ";;;; BEGIN ~A~%"
(pretty-functor lbl (wam-functors wam)))))
(format t ";~A~4,'0X: "
(if (= (wam-program-counter wam) addr)
">>"
" ")
addr)
(format t "~A~%" (instruction-details (aref instruction 0)
(rest (coerce instruction 'list))
(wam-functors wam))))
(incf addr (length instruction))))))
(defun dump-code
(wam
&optional
(from (max (- (wam-program-counter wam) 8) ; wow
0)) ; this
(to (min (+ (wam-program-counter wam) 8) ; is
(length (wam-code wam))))) ; bad
(format t "CODE (size: ~D frame(s) / ~:[OPEN~;CLOSED~])~%"
(length (wam-logic-stack wam))
(wam-logic-closed-p wam))
(dump-code-store wam (wam-code wam) from to))
(defun dump-wam-registers (wam)
(format t "REGISTERS:~%")
(format t "~5@A -> ~8X~%" "S" (wam-subterm wam))
(loop :for register :from 0 :to +register-count+
:for contents :across (wam-store wam)
:when (not (cell-null-p contents))
:do
(format t "~5@A -> ~8,'0X ~10A ~A~%"
(format nil "X~D" register)
contents
(cell-aesthetic contents)
(format nil "; ~A" (first (extract-things wam (list register)))))))
(defun dump-wam-functors (wam)
(format t " FUNCTORS: ~S~%" (wam-functors wam)))
(defun dump-wam-trail (wam)
(format t " TRAIL: ")
(loop :for addr :across (wam-trail wam) :do
(format t "~4,'0X ~A //"
addr
(cell-aesthetic (wam-store-cell wam addr))))
(format t "~%"))
(defun dump-labels (wam)
(format t "LABELS:~%~{ ~A -> ~4,'0X~^~%~}~%"
(loop :for functor-index
:being :the :hash-keys :of (wam-code-labels wam)
:using (hash-value address)
:nconc (list (pretty-functor functor-index
(wam-functors wam))
address))))
(defun dump-wam (wam from to highlight)
(format t " FAIL: ~A~%" (wam-fail wam))
(format t " BACKTRACKED?: ~A~%" (wam-backtracked wam))
(format t " MODE: ~S~%" (wam-mode wam))
(dump-wam-functors wam)
(format t " HEAP SIZE: ~A~%" (- (wam-heap-pointer wam) +heap-start+))
(format t " PROGRAM COUNTER: ~4,'0X~%" (wam-program-counter wam))
(format t "CONTINUATION PTR: ~4,'0X~%" (wam-continuation-pointer wam))
(format t " ENVIRONMENT PTR: ~4,'0X~%" (wam-environment-pointer wam))
(format t " BACKTRACK PTR: ~4,'0X~%" (wam-backtrack-pointer wam))
(format t " CUT PTR: ~4,'0X~%" (wam-cut-pointer wam))
(format t "HEAP BCKTRCK PTR: ~4,'0X~%" (wam-heap-backtrack-pointer wam))
(dump-wam-trail wam)
(dump-wam-registers wam)
(format t "~%")
(dump-heap wam from to highlight)
(format t "~%")
(dump-stack wam)
(format t "~%")
(dump-labels wam)
(dump-code wam))
(defun dump-wam-query-code (wam &optional (max +maximum-query-size+))
(with-slots (code) wam
(dump-code-store wam code 0 max)))
(defun dump-wam-code (wam)
(with-slots (code) wam
(dump-code-store wam code +maximum-query-size+ (length code))))
(defun dump-wam-full (wam)
(dump-wam wam +heap-start+ (wam-heap-pointer wam) -1))
(defun dump-wam-around (wam addr width)
(dump-wam wam
(max +heap-start+ (- addr width))
(min (wam-heap-pointer wam)
(+ addr width 1))
addr))