;;; compiler.lisp ---
-;; copyright (C) 2013 David Vazquez
+;; Copyright (C) 2013 David Vazquez
;; JSCL is free software: you can redistribute it and/or
;; modify it under the terms of the GNU General Public License as
(in-package :jscl)
-;;;; Utils
+;;;; Utilities
+;;;;
+;;;; Random Common Lisp code useful to use here and there.
+
+(defmacro with-gensyms ((&rest vars) &body body)
+ `(let ,(mapcar (lambda (var) `(,var (gensym ,(concatenate 'string (string var) "-")))) vars)
+ ,@body))
(defun singlep (x)
(and (consp x) (null (cdr x))))
(assert (singlep x))
(first x))
-;;;; Intermediate representation
+(defun generic-printer (x stream)
+ (print-unreadable-object (x stream :type t :identity t)))
+
+
+;;;; Intermediate representation structures
;;;;
;;;; This intermediate representation (IR) is a simplified version of
-;;;; first intermediate representation what you will find if you have
-;;;; a you have the source code of SBCL. Some terminology is also
+;;;; the first intermediate representation what you will find if you
+;;;; have a look to the source code of SBCL. Some terminology is also
;;;; used, but other is changed, so be careful if you assume you know
;;;; what it is because you know the name.
;;;;
+;;;; Computations are represented by `node'. Nodes are grouped
+;;;; sequencially into `basic-block'. It is a plain representation
+;;;; rather than a nested one. Computations take data and produce a
+;;;; value. Both data transfer are represented by `lvar'.
-;;; A leaf stands for leaf in the tree of computations. Lexical
-;;; variables, constants and literal functions are leafs. Leafs are
-;;; not nodes itself, a `ref' node will stands for putting a leaf into
-;;; a lvar, which can be used in computations.
(defstruct leaf)
-;;; Reference a lexical variable. Special variables have not a
-;;; representation in IR. They are handled via the primitive functions
-;;; `%symbol-function' and `%symbol-value'.
+;;; A (lexical) variable. Special variables has not a special
+;;; representation in the IR. They are handled by the primitive
+;;; functions `%symbol-function' and `%symbol-value'.
(defstruct (var (:include leaf))
- ;; Name is the symbol used to identify this variable in the lexical
- ;; environment.
+ ;; The symbol which names this variable in the source code.
name)
-;;; A constant value, mostly from a quoted form, but maybe introduced
-;;; in some pass of the compiler.
+;;; A literal Lisp object. It usually comes from a quoted expression.
(defstruct (constant (:include leaf))
+ ;; The object itself.
value)
-;;; A literal function. Why do we use `functional' as name? Well,
-;;; function is taken, isn't it?
-(defstruct (functional (:include leaf))
- ;; The symbol which names this function in the source code.
+;;; A lambda expression. Why do we name it `functional'? Well,
+;;; function is reserved by the ANSI, isn't it?
+(defstruct (functional (:include leaf) (:print-object generic-printer))
+ ;; The symbol which names this function in the source code or null
+ ;; if we do not know or it is an anonymous function.
name
- ;; A list of lvars which are bound to the argument values in a call
- ;; to this function.
arguments
- ;; LVAR which contains the return values of the function.
return-lvar
- ;; The basic block which contain the code which be executed firstly
- ;; when you call this function.
entry-point)
-
-;;; Used to transfer data between the computations in the intermediate
-;;; representation. Each node is valued into a LVar. And nodes which
-;;; use resulting values from other nodes use such LVar.
+;;; An abstract place where the result of a computation is stored and
+;;; it can be referenced from other nodes, so lvars are responsible
+;;; for keeping the necessary information of the nested structure of
+;;; the code in this plain representation.
(defstruct lvar
(id (gensym "$")))
-;;; A computation node. It represents a simple computation in the
-;;; intermediate representation. Nodes are grouped in basic blocks,
-;;; which are delimited by the special nodes `block-entry' and
-;;; `block-exit'. Resulting value of the node is stored in LVAR, which it
-;;; could be null if the value is discarded.
-(defstruct node
- next
- prev
+;;; A base structure for every single computation. Most of the
+;;; computations are valued.
+(defstruct (node (:print-object generic-printer))
+ ;; The next and the prev slots are the next nodes and the previous
+ ;; node in the basic block sequence respectively.
+ next prev
+ ;; Lvar which stands for the result of the computation of this node.
lvar)
-;;; Sentinel nodes. No computation really, but they make easier to
-;;; manipulate the doubly linked-list.
+;;; Sentinel nodes in the basic block sequence of nodes.
(defstruct (block-entry (:include node)))
(defstruct (block-exit (:include node)))
-;;; A reference to a leaf.
+;;; A reference to a leaf (variable, constant and functions). The
+;;; meaning of this node is leaving the leaf into the lvar of the
+;;; node.
(defstruct (ref (:include node))
leaf)
variable
value)
-;;; Call the lvar FUNCTION with a list of lvars as ARGUMENTS.
-(defstruct (call (:include node))
- function
+;;; A base node to function calls with a list of lvar as ARGUMENTS.
+(defstruct (combination (:include node) (:constructor))
arguments)
+;;; A function call to the ordinary Lisp function in the lvar FUNCTION.
+(defstruct (call (:include combination))
+ function)
+
+;;; A function call to the primitive FUNCTION.
+(defstruct (primitive-call (:include combination))
+ function)
+
+
;;; A conditional branch. If the LVAR is not NIL, then we will jump to
;;; the basic block CONSEQUENT, jumping to ALTERNATIVE otherwise. By
;;; definition, a conditional must appear at the end of a basic block.
alternative)
-;;; BBlock stands for `basic block', which is a maximal sequence of
-;;; nodes with an entry point and an exit. Basic blocks are organized
-;;; as a control flow graph with some more information in omponents.
-(defstruct bblock
- (id (gensym "L"))
- succ
- pred
+;;;; Components
+;;;;
+;;;; Components are connected pieces of the control flow graph of
+;;;; basic blocks with some additional information. Components have
+;;;; well-defined entry and exit nodes. It is the toplevel
+;;;; organizational entity in the compiler. The IR translation result
+;;;; is accumulated into components incrementally.
+(defstruct (component (:print-object generic-printer))
entry
exit)
-(defstruct (component-entry (:include bblock)))
-(defstruct (component-exit (:include bblock)))
+;;; The current component. We accumulate the results of the IR
+;;; conversion in this component.
+(defvar *component*)
+
+;;; Create a new component with an empty basic block, ready to start
+;;; conversion to IR. It returns the component and the basic block as
+;;; multiple values.
+(defun make-empty-component ()
+ (let ((*component* (make-component)))
+ (let ((entry (make-component-entry))
+ (block (make-empty-block))
+ (exit (make-component-exit)))
+ (setf (block-succ entry) (list block)
+ (block-pred exit) (list block)
+ (block-succ block) (list exit)
+ (block-pred block) (list entry)
+ (component-entry *component*) entry
+ (component-exit *component*) exit)
+ (values *component* block))))
+
+;;; Prepare a new component with a current empty block ready to start
+;;; IR conversion bound in the current cursor. BODY is evaluated and
+;;; the value of the last form is returned.
+(defmacro with-component-compilation (&body body)
+ (with-gensyms (block)
+ `(multiple-value-bind (*component* ,block)
+ (make-empty-component)
+ (let ((*cursor* (cursor :block ,block)))
+ ,@body))))
+
+;;; Return the list of blocks in COMPONENT, conveniently sorted.
+(defun component-blocks (component)
+ (let ((seen nil)
+ (output nil))
+ (labels ((compute-rdfo-from (block)
+ (unless (or (component-exit-p block) (find block seen))
+ (push block seen)
+ (dolist (successor (block-succ block))
+ (unless (component-exit-p block)
+ (compute-rdfo-from successor)))
+ (push block output))))
+ (compute-rdfo-from (unlist (block-succ (component-entry component))))
+ output)))
+
+;;; Iterate across different blocks in COMPONENT.
+(defmacro do-blocks ((block component &optional result) &body body)
+ `(dolist (,block (component-blocks ,component) ,result)
+ ,@body))
-(defun make-empty-bblock ()
+(defmacro do-blocks-backward ((block component &optional result) &body body)
+ `(dolist (,block (reverse (component-blocks ,component)) ,result)
+ ,@body))
+
+;;; A few consistency checks in the IR useful for catching bugs.
+(defun check-ir-consistency (&optional (component *component*))
+ (with-simple-restart (continue "Continue execution")
+ (do-blocks (block component)
+ (dolist (succ (block-succ block))
+ (unless (find block (block-pred succ))
+ (error "The block `~S' does not belong to the predecessors list of the its successor `~S'"
+ (block-id block)
+ (block-id succ))))
+ (dolist (pred (block-pred block))
+ (unless (find block (block-succ pred))
+ (error "The block `~S' does not belong to the successors' list of its predecessor `~S'"
+ (block-id block)
+ (block-id pred)))))))
+
+
+;;; Blocks are `basic block`. Basic blocks are organized as a control
+;;; flow graph with some more information in omponents.
+(defstruct (basic-block
+ (:conc-name "BLOCK-")
+ (:constructor make-block)
+ (:predicate block-p))
+ (id (gensym "L"))
+ ;; List of successors and predecessors of this basic block.
+ succ pred
+ ;; The sentinel nodes of the sequence.
+ entry exit
+ ;; The component where this block belongs
+ (component *component*))
+
+;;; Sentinel nodes in the control flow graph of basic blocks.
+(defstruct (component-entry (:include basic-block)))
+(defstruct (component-exit (:include basic-block)))
+
+;;; Return a fresh empty basic block.
+(defun make-empty-block ()
(let ((entry (make-block-entry))
(exit (make-block-exit)))
(setf (node-next entry) exit
(node-prev exit) entry)
- (make-bblock :entry entry :exit exit)))
+ (make-block :entry entry :exit exit)))
+;;; Return T if B is an empty basic block and NIL otherwise.
(defun empty-block-p (b)
- (block-exit-p (node-next (bblock-entry b))))
+ (block-exit-p (node-next (block-entry b))))
+
+;;; Iterate across the nodes in a basic block forward.
+(defmacro do-nodes
+ ((node block &optional result &key include-sentinel-p) &body body)
+ `(do ((,node ,(if include-sentinel-p
+ `(block-entry ,block)
+ `(node-next (block-entry ,block)))
+ (node-next ,node)))
+ (,(if include-sentinel-p
+ `(null ,node)
+ `(block-exit-p ,node))
+ ,result)
+ ,@body))
-(defmacro do-nodes ((node block &optional result) &body body)
- (check-type node symbol)
- `(do ((,node (node-next (bblock-entry ,block)) (node-next ,node)))
- ((block-exit-p ,node) ,result)
+;;; Iterate across the nodes in a basic block backward.
+(defmacro do-nodes-backward
+ ((node block &optional result &key include-sentinel-p) &body body)
+ `(do ((,node ,(if include-sentinel-p
+ `(block-exit ,block)
+ `(node-prev (block-entry ,block)))
+ (node-prev ,node)))
+ (,(if include-sentinel-p
+ `(null ,node)
+ `(block-entry-p ,node))
+ ,result)
,@body))
;;; Link FROM and TO nodes together. FROM and TO must belong to the
(node-prev to) from)
(values))
-;;; Insert NODE before NEXT.
-(defun insert-node-before (next node)
- (link-nodes (node-prev next) node)
- (link-nodes node next))
-;;; Components are connected pieces of the control flow graph with
-;;; some additional information. Components have well-defined entry
-;;; and exit nodes. They also track what basic blocks we have and
-;;; other useful information. It is the toplevel organizational entity
-;;; in the compiler. The IR translation result is accumulated into
-;;; components incrementally.
-(defstruct (component
- #-jscl (:print-object print-component))
- entry
- exit
- blocks)
-
-;;; Create a new component, compromised of the sentinel nodes and a
-;;; empty basic block, ready to start conversion to IR. It returnes
-;;; the component and the basic block as multiple values.
-(defun make-empty-component ()
- (let ((entry (make-component-entry))
- (bblock (make-empty-bblock))
- (exit (make-component-exit)))
- (setf (bblock-succ entry) (list bblock)
- (bblock-pred exit) (list bblock)
- (bblock-succ bblock) (list exit)
- (bblock-pred bblock) (list entry))
- (values (make-component :entry entry :exit exit) bblock)))
-
-;;; Delete an empty block. It is the same as a jump to an
-;;; uncondiditonal jump.
-(defun delete-empty-block (block)
+;;;; Cursors
+;;;;
+;;;; A cursor is a point between two nodes in some basic block in the
+;;;; IR representation where manipulations can take place, similarly
+;;;; to the cursors in text editing.
+;;;;
+;;;; Cursors cannot point to special component's entry and exit basic
+;;;; blocks or after a conditional node. Conveniently, the `cursor'
+;;;; function will signal an error if the cursor is not positioned
+;;;; correctly, so the rest of the code does not need to check once
+;;;; and again.
+
+(defstruct cursor
+ block next)
+
+;;; The current cursor. It is the default cursor for many functions
+;;; which work on cursors.
+(defvar *cursor*)
+
+;;; Return the current basic block. It is to say, the basic block
+;;; where the current cursor is pointint.
+(defun current-block ()
+ (cursor-block *cursor*))
+
+;;; Create a cursor which points to the basic block BLOCK. If omitted,
+;;; then the current block is used.
+;;;
+;;; The keywords AFTER and BEFORE specify the cursor will point after (or
+;;; before) that node respectively. If none is specified, the cursor is
+;;; created before the exit node in BLOCK. An error is signaled if both
+;;; keywords are specified inconsistently, or if the nodes do not belong
+;;; to BLOCK.
+;;;
+;;; AFTER and BEFORE could also be the special values :ENTRY and :EXIT,
+;;; which stand for the entry and exit nodes of the block respectively.
+(defun cursor (&key (block (current-block))
+ (before nil before-p)
+ (after nil after-p))
(when (or (component-entry-p block) (component-exit-p block))
- (error "Cannot delete entry or exit basic blocks."))
- (unless (empty-block-p block)
- (error "Block `~S' is not empty!" (bblock-id block)))
- (assert (singlep (bblock-succ block)))
- (let ((successor (first (bblock-succ block))))
- (dolist (pred (bblock-pred block))
- (setf (bblock-succ pred)
- (substitute successor block (bblock-succ pred)))
- (pushnew pred (bblock-pred successor)))))
-
-(defun finish-component (&optional (component *component*))
- (dolist (blk (bblock-pred (component-exit component)))
- (when (empty-block-p blk)
- (delete-empty-block blk))))
+ (error "Invalid cursor on special entry/exit basic block."))
+ ;; Handle special values :ENTRY and :EXIT.
+ (flet ((node-designator (x)
+ (case x
+ (:entry (block-entry block))
+ (:exit (block-exit block))
+ (t x))))
+ (setq before (node-designator before))
+ (setq after (node-designator after)))
+ (let* ((next (or before (and after (node-next after)) (block-exit block)))
+ (cursor (make-cursor :block block :next next)))
+ (flet ((out-of-range-cursor ()
+ (error "Out of range cursor."))
+ (ambiguous-cursor ()
+ (error "Ambiguous cursor specified between two non-adjacent nodes.")))
+ (when (conditional-p (node-prev next))
+ (error "Invalid cursor after conditional node."))
+ (when (or (null next) (block-entry-p next))
+ (out-of-range-cursor))
+ (when (and before-p after-p (not (eq after before)))
+ (ambiguous-cursor))
+ (do-nodes-backward (node block (out-of-range-cursor) :include-sentinel-p t)
+ (when (eq next node) (return))))
+ cursor))
+
+;;; Accept a cursor specification just as described in `cursor'
+;;; describing a position in the IR and modify destructively the
+;;; current cursor to point there.
+(defun set-cursor (&rest cursor-spec)
+ (let ((newcursor (apply #'cursor cursor-spec)))
+ (setf (cursor-block *cursor*) (cursor-block newcursor))
+ (setf (cursor-next *cursor*) (cursor-next newcursor))
+ *cursor*))
+
+;;; Insert NODE at cursor.
+(defun insert-node (node &optional (cursor *cursor*))
+ ;; After if? wrong!
+ (link-nodes (node-prev (cursor-next cursor)) node)
+ (link-nodes node (cursor-next cursor))
+ t)
+
+;;; Split the block at CURSOR. The cursor will point to the end of the
+;;; first basic block. Return the three basic blocks as multiple
+;;; values.
+(defun split-block (&optional (cursor *cursor*))
+ ;; <aaaaa|zzzzz> ==> <aaaaa|>--<zzzzz>
+ (let* ((block (cursor-block cursor))
+ (newexit (make-block-exit))
+ (newentry (make-block-entry))
+ (exit (block-exit block))
+ (newblock (make-block :entry newentry
+ :exit exit
+ :pred (list block)
+ :succ (block-succ block))))
+ (insert-node newexit)
+ (insert-node newentry)
+ (setf (node-next newexit) nil)
+ (setf (node-prev newentry) nil)
+ (setf (block-exit block) newexit)
+ (setf (block-succ block) (list newblock))
+ (dolist (succ (block-succ newblock))
+ (setf (block-pred succ) (substitute newblock block (block-pred succ))))
+ (set-cursor :block block :before newexit)
+ newblock))
-;;; IR Translation
+;;; Split the block at CURSOR if it is in the middle of it. The cursor
+;;; will point to the end of the first basic block. Return the three
+;;; basic blocks as multiple values.
+(defun maybe-split-block (&optional (cursor *cursor*))
+ ;; If we are converting IR into the end of the basic block, it's
+ ;; fine, we don't need to do anything.
+ (unless (block-exit-p (cursor-next cursor))
+ (split-block cursor)))
-;;; The current component. We accumulate the results of the IR
-;;; conversion in this component.
-(defvar *component*)
-;;; The current block in the current component. IR conversion usually
-;;; append nodes to this block. Branching instructions will modify
-;;; this variable.
-(defvar *bblock*)
-;;; Prepare a new component with a current empty content block ready
-;;; to start IR conversion. Then BODY is evaluated and the value of
-;;; the last form is returned.
-(defmacro with-component-compilation (&body body)
- `(multiple-value-bind (*component* *bblock*)
- (make-empty-component)
- ,@body))
+;;;; Lexical environment
+;;;;
+;;;; It keeps an association between names and the IR entities. It is
+;;;; used to guide the translation from the Lisp source code to the
+;;;; intermediate representation.
-;;; The Lexical environment is compromised of a list of bindings,
-;;; which associates information to symbols. It tracks lexical
-;;; variables, tags, local declarations and many other information in
-;;; order to guide the compiler.
(defstruct binding
- name type value declarations)
+ name namespace type value)
-(defstruct lexenv
- bindings)
+(defvar *lexenv* nil)
-;;; A alist of IR translator functions.
-(defvar *ir-translator* nil)
+(defun find-binding (name namespace)
+ (find-if (lambda (b)
+ (and (eq (binding-name b) name)
+ (eq (binding-namespace b) namespace)))
+ *lexenv*))
-;;; Define a IR translator for NAME.
-(defmacro define-ir-translator (name (next result) lambda-list &body body)
- (let ((fname (intern (format nil "IR-CONVERT-~a" (string name))))
- (form (gensym)))
- (check-type name symbol)
- (check-type next symbol)
- `(progn
- (defun ,fname (,form ,next ,result)
- (destructuring-bind ,lambda-list ,form
- ,@body))
- (push (cons ',name #',fname) *ir-translator*))))
+(defun push-binding (name namespace value &optional type)
+ (push (make-binding :name name
+ :namespace namespace
+ :type type
+ :value value)
+ *lexenv*))
-(defun ir-convert-constant (form next result)
- (let* ((leaf (make-constant :value form))
- (ref (make-ref :leaf leaf :lvar result)))
- (insert-node-before next ref)))
+;;;; IR Translation
+;;;;
+;;;; This code covers the translation from Lisp source code to the
+;;;; intermediate representation. The main entry point function to do
+;;;; that is the `ir-convert' function, which dispatches to IR
+;;;; translators. This function ss intended to do the initial
+;;;; conversion as well as insert new IR code during optimizations.
+;;;;
+;;;; The function `ir-complete' will coalesce basic blocks in a
+;;;; component to generate proper maximal basic blocks.
-(define-ir-translator quote (next result) (form)
- (ir-convert-constant form next result))
+;;; A alist of IR translator functions.
+(defvar *ir-translator* nil)
-(define-ir-translator setq (next result) (variable value)
+;;; Define a IR translator for NAME. LAMBDA-LIST is used to
+;;; destructure the arguments of the form. Calling the local function
+;;; `result-lvar' you can get the LVAR where the compilation of the
+;;; expression should store the result of the evaluation.
+;;;
+;;; The cursor is granted to be at the end of a basic block with a
+;;; unique successor, and so it should be when the translator returns.
+(defmacro define-ir-translator (name lambda-list &body body)
+ (check-type name symbol)
+ (let ((fname (intern (format nil "IR-CONVERT-~a" (string name)))))
+ (with-gensyms (result form)
+ `(progn
+ (defun ,fname (,form ,result)
+ (flet ((result-lvar () ,result))
+ (declare (ignorable (function result-lvar)))
+ (destructuring-bind ,lambda-list ,form
+ ,@body)))
+ (push (cons ',name #',fname) *ir-translator*)))))
+
+;;; Return the unique successor of the current block. If it is not
+;;; unique signal an error.
+(defun next-block ()
+ (unlist (block-succ (current-block))))
+
+;;; Set the next block of the current one.
+(defun (setf next-block) (new-value)
+ (let ((block (current-block)))
+ (dolist (succ (block-succ block))
+ (setf (block-pred succ) (remove block (block-pred succ))))
+ (setf (block-succ block) (list new-value))
+ (push block (block-pred new-value))
+ new-value))
+
+(defun ir-convert-constant (form result)
+ (let* ((leaf (make-constant :value form)))
+ (insert-node (make-ref :leaf leaf :lvar result))))
+
+(define-ir-translator quote (form)
+ (ir-convert-constant form (result-lvar)))
+
+(define-ir-translator setq (variable value)
(let ((var (make-var :name variable))
(value-lvar (make-lvar)))
- (ir-convert value next value-lvar)
- (let ((assign (make-assignment :variable var :value value-lvar :lvar result)))
- (insert-node-before next assign))))
-
-;;; Split BLOCK in two basic blocks. BLOCK ends just before BLOCK. A
-;;; new block is created starting at NODE until the exit of the
-;;; original block. The successors of BLOCK become the successors of
-;;; the new block.
-(defun split-basic-block-before (node block)
- (let ((exit (node-prev (bblock-exit block)))
- (newexit (make-block-exit))
- (newentry (make-block-entry))
- newblock)
- (insert-node-before node newentry)
- (insert-node-before newentry newexit)
- (setf (node-next newexit) nil)
- (setf (node-prev newentry) nil)
- (setf (bblock-exit block) newexit)
- (setq newblock (make-bblock :entry newentry :exit exit))
- (rotatef (bblock-succ block) (bblock-succ newblock))
- newblock))
-
-(define-ir-translator if (next result) (test then &optional else)
+ (ir-convert value value-lvar)
+ (let ((assign (make-assignment :variable var :value value-lvar :lvar (result-lvar))))
+ (insert-node assign))))
+
+(define-ir-translator progn (&body body)
+ (mapc #'ir-convert (butlast body))
+ (ir-convert (car (last body)) (result-lvar)))
+
+(define-ir-translator if (test then &optional else)
+ ;; It is the schema of how the basic blocks will look like
+ ;;
+ ;; / ..then.. \
+ ;; <aaaaXX> --< >-- <|> -- <zzzz>
+ ;; \ ..else.. /
+ ;;
+ ;; Note that is important to leave the cursor in an empty basic
+ ;; block, as zzz could be the exit basic block of the component,
+ ;; which is an invalid position for a cursor.
(let ((test-lvar (make-lvar))
- (then-block (make-empty-bblock))
- (else-block (make-empty-bblock))
- (join-block (make-empty-bblock)))
- ;; Convert the test into the current basic block.
- (ir-convert test next test-lvar)
- (setq next (bblock-exit *bblock*))
- (let ((cond (make-conditional :test test-lvar :consequent then-block :alternative else-block)))
- (insert-node-before next cond))
- ;; If we are not at the end of the content block, split it.
- (unless (block-exit-p next)
- (setq join-block (split-basic-block-before next *bblock*)))
- (dolist (succ (bblock-succ *bblock*))
- (setf (bblock-pred succ) (substitute join-block *bblock* (bblock-pred succ))))
- (psetf (bblock-succ *bblock*) (list else-block then-block)
- (bblock-pred else-block) (list *bblock*)
- (bblock-pred then-block) (list *bblock*)
- (bblock-succ then-block) (list join-block)
- (bblock-succ else-block) (list join-block)
- (bblock-pred join-block) (list else-block then-block)
- (bblock-succ join-block) (bblock-succ *bblock*))
- (let ((*bblock* then-block))
- (ir-convert then (bblock-exit then-block) result))
- (let ((*bblock* else-block))
- (ir-convert else (bblock-exit else-block) result))
- (setq *bblock* join-block)))
-
-
-(defun ir-convert-var (form next result)
- (let* ((leaf (make-var :name form))
- (ref (make-ref :leaf leaf :lvar result)))
- (insert-node-before next ref)))
-
-(defun ir-convert-call (form next result)
+ (then-block (make-empty-block))
+ (else-block (make-empty-block))
+ (join-block (make-empty-block)))
+ (ir-convert test test-lvar)
+ (insert-node (make-conditional :test test-lvar :consequent then-block :alternative else-block))
+ (let* ((block (current-block))
+ (tail-block (next-block)))
+ ;; Link together the different created basic blocks.
+ (setf (block-succ block) (list else-block then-block)
+ (block-pred else-block) (list block)
+ (block-pred then-block) (list block)
+ (block-succ then-block) (list join-block)
+ (block-succ else-block) (list join-block)
+ (block-pred join-block) (list else-block then-block)
+ (block-succ join-block) (list tail-block)
+ (block-pred tail-block) (substitute join-block block (block-pred tail-block))))
+ ;; Convert he consequent and alternative forms and update cursor.
+ (ir-convert then (result-lvar) (cursor :block then-block))
+ (ir-convert else (result-lvar) (cursor :block else-block))
+ (set-cursor :block join-block)))
+
+(define-ir-translator block (name &body body)
+ (let ((new (split-block)))
+ (push-binding name 'block (cons (next-block) (result-lvar)))
+ (ir-convert `(progn ,@body) (result-lvar))
+ (set-cursor :block new)))
+
+(define-ir-translator return-from (name &optional value)
+ (let ((binding
+ (or (find-binding name 'block)
+ (error "Tried to return from unknown block `~S' name" name))))
+ (destructuring-bind (jump-block . lvar)
+ (binding-value binding)
+ (ir-convert value lvar)
+ (setf (next-block) jump-block)
+ ;; This block is really unreachable, even if the following code
+ ;; is labelled in a tagbody, as tagbody will create a new block
+ ;; for each label. However, we have to leave the cursor
+ ;; somewhere to convert new input.
+ (let ((dummy (make-empty-block)))
+ (set-cursor :block dummy)))))
+
+(define-ir-translator tagbody (&rest statements)
+ (flet ((go-tag-p (x)
+ (or (integerp x) (symbolp x))))
+ (let* ((tags (remove-if-not #'go-tag-p statements))
+ (tag-blocks nil))
+ ;; Create a chain of basic blocks for the tags, recording each
+ ;; block in a alist in TAG-BLOCKS.
+ (let ((*cursor* *cursor*))
+ (dolist (tag tags)
+ (setq *cursor* (cursor :block (split-block)))
+ (push-binding tag 'tag (current-block))
+ (if (assoc tag tag-blocks)
+ (error "Duplicated tag `~S' in tagbody." tag)
+ (push (cons tag (current-block)) tag-blocks))))
+ ;; Convert the statements into the correct block.
+ (dolist (stmt statements)
+ (if (go-tag-p stmt)
+ (set-cursor :block (cdr (assoc stmt tag-blocks)))
+ (ir-convert stmt))))))
+
+(define-ir-translator go (label)
+ (let ((tag-binding
+ (or (find-binding label 'tag)
+ (error "Unable to jump to the label `~S'" label))))
+ (setf (next-block) (binding-value tag-binding))
+ ;; Unreachable block.
+ (let ((dummy (make-empty-block)))
+ (set-cursor :block dummy))))
+
+
+(defun ir-convert-functoid (result name arguments &rest body)
+ (let ((component)
+ (return-lvar (make-lvar)))
+ (with-component-compilation
+ (ir-convert `(progn ,@body) return-lvar)
+ (setq component *component*))
+ (let ((functional
+ (make-functional
+ :name name
+ :arguments arguments
+ :entry-point component
+ :return-lvar return-lvar)))
+ (insert-node (make-ref :leaf functional :lvar result)))))
+
+(define-ir-translator function (name)
+ (if (atom name)
+ (ir-convert `(symbol-function ,name) (result-lvar))
+ (ecase (car name)
+ ((lambda named-lambda)
+ (let ((desc (cdr name)))
+ (when (eq 'lambda (car name))
+ (push nil desc))
+ (apply #'ir-convert-functoid (result-lvar) desc)))
+ (setf))))
+
+(defun ir-convert-var (form result)
+ (let ((binds (find-binding form 'variable)))
+ (if binds
+ (insert-node (make-ref :leaf (binding-value binds) :lvar result))
+ (ir-convert `(symbol-value ',form) result))))
+
+(defun ir-convert-call (form result)
(destructuring-bind (function &rest args) form
(let ((func-lvar (make-lvar))
(args-lvars nil))
- (when (symbolp function)
- (ir-convert `(%symbol-function ,function) next func-lvar))
+ ;; Argument list
(dolist (arg args)
- (push (make-lvar) args-lvars)
- (ir-convert arg next (first args-lvars)))
+ (let ((arg-lvar (make-lvar)))
+ (push arg-lvar args-lvars)
+ (ir-convert arg arg-lvar)))
(setq args-lvars (reverse args-lvars))
- (let ((call (make-call :function func-lvar :arguments args-lvars :lvar result)))
- (insert-node-before next call)))))
-
-
-;;; Convert the Lisp expression FORM into IR before the NEXT node, it
-;;; may create new basic blocks into the current component. During the
-;;; initial IR conversion, The NEXT node is the EXIT node of the
-;;; current basic block, but optimizations could call it to insert IR
-;;; code somewhere.
-(defun ir-convert (form next result)
- (when (block-entry-p next)
- (error "Can't insert IR before the entry node."))
- (cond
- ((atom form)
- (cond
- ((symbolp form)
- (ir-convert-var form next result))
- (t
- (ir-convert-constant form next result))))
- (t
- (destructuring-bind (op &rest args) form
- (let ((translator (cdr (assoc op *ir-translator*))))
- (if translator
- (funcall translator args next result)
- (ir-convert-call form next result))))))
- (values))
+ ;; Funcall
+ (if (find-primitive function)
+ (insert-node (make-primitive-call
+ :function (find-primitive function)
+ :arguments args-lvars
+ :lvar result))
+ (progn
+ (ir-convert `(symbol-function ,function) func-lvar)
+ (insert-node (make-call :function func-lvar
+ :arguments args-lvars
+ :lvar result)))))))
+
+;;; Convert the Lisp expression FORM, it may create new basic
+;;; blocks. RESULT is the lvar representing the result of the
+;;; computation or null if the value should be discarded. The IR is
+;;; inserted at *CURSOR*.
+(defun ir-convert (form &optional result (*cursor* *cursor*))
+ ;; Rebinding the lexical environment here we make sure that the
+ ;; lexical information introduced by FORM is just available for
+ ;; subforms.
+ (let ((*lexenv* *lexenv*))
+ ;; Possibly create additional blocks in order to make sure the
+ ;; cursor is at end the end of a basic block.
+ (maybe-split-block)
+ (cond
+ ((atom form)
+ (cond
+ ((symbolp form)
+ (ir-convert-var form result))
+ (t
+ (ir-convert-constant form result))))
+ (t
+ (destructuring-bind (op &rest args) form
+ (let ((translator (cdr (assoc op *ir-translator*))))
+ (if translator
+ (funcall translator args result)
+ (ir-convert-call form result))))))
+ (values)))
+
+
+;;; Change all the predecessors of BLOCK to precede NEW-BLOCK instead.
+(defun replace-block (block new-block)
+ (let ((predecessors (block-pred block)))
+ (setf (block-pred new-block) (union (block-pred new-block) predecessors))
+ (dolist (pred predecessors)
+ (setf (block-succ pred) (substitute new-block block (block-succ pred)))
+ (unless (component-entry-p pred)
+ (let ((last-node (node-prev (block-exit pred))))
+ (when (conditional-p last-node)
+ (macrolet ((replacef (place)
+ `(setf ,place (if (eq block ,place) new-block ,place))))
+ (replacef (conditional-consequent last-node))
+ (replacef (conditional-alternative last-node)))))))))
+
+(defun delete-empty-block (block)
+ (when (or (component-entry-p block) (component-exit-p block))
+ (error "Cannot delete entry or exit basic blocks."))
+ (unless (empty-block-p block)
+ (error "Block `~S' is not empty!" (block-id block)))
+ (replace-block block (unlist (block-succ block))))
+
+;;; Try to coalesce BLOCK with the successor if it is unique and block
+;;; is its unique predecessor.
+(defun maybe-coalesce-block (block)
+ (when (singlep (block-succ block))
+ (let ((succ (first (block-succ block))))
+ (when (and (not (component-exit-p succ)) (singlep (block-pred succ)))
+ (link-nodes (node-prev (block-exit block))
+ (node-next (block-entry succ)))
+ (setf (block-succ block) (block-succ succ))
+ (dolist (next (block-succ succ))
+ (setf (block-pred next) (substitute block succ (block-pred next))))
+ t))))
+
+(defun ir-complete (&optional (component *component*))
+ (do-blocks-backward (block component)
+ (maybe-coalesce-block block)
+ (when (empty-block-p block)
+ (delete-empty-block block))))
-(defun compute-dfo (component)
- (or (component-blocks component)
- (let ((output nil))
- (labels ((compute-dfo-from (block)
- (unless (or (component-exit-p block) (find block output))
- (dolist (successor (bblock-succ block))
- (unless (component-exit-p block)
- (compute-dfo-from successor)))
- (push block output))))
- (compute-dfo-from (unlist (bblock-succ (component-entry component))))
- (setf (component-blocks component) output)))))
-
-(defmacro do-blocks ((bblock component &optional result) &body body)
- `(dolist (,bblock (compute-dfo ,component) ,result)
- ,@body))
;;; IR Debugging
((var-p leaf)
(format t "~a" (var-name leaf)))
((constant-p leaf)
- (format t "'~a" (constant-value leaf)))
+ (format t "'~s" (constant-value leaf)))
((functional-p leaf)
- (format t "#<function ~a at ~a>"
- (functional-name leaf)
- (functional-entry-point leaf))))))
+ (format t "#<function ~a>" (functional-name leaf))))))
((assignment-p node)
(format t "set ~a ~a"
(var-name (assignment-variable node))
(lvar-id (assignment-value node))))
+ ((primitive-call-p node)
+ (format t "primitive ~a" (primitive-name (primitive-call-function node)))
+ (dolist (arg (primitive-call-arguments node))
+ (format t " ~a" (lvar-id arg))))
((call-p node)
(format t "call ~a" (lvar-id (call-function node)))
(dolist (arg (call-arguments node))
((conditional-p node)
(format t "if ~a ~a ~a"
(lvar-id (conditional-test node))
- (bblock-id (conditional-consequent node))
- (bblock-id (conditional-alternative node))))
+ (block-id (conditional-consequent node))
+ (block-id (conditional-alternative node))))
(t
(error "`print-node' does not support printing ~S as a node." node)))
(terpri))
-(defun print-bblock (block)
- (flet ((bblock-name (block)
+(defun print-block (block)
+ (flet ((block-name (block)
(cond
- ((and (singlep (bblock-pred block))
- (component-entry-p (bblock-pred block)))
+ ((and (singlep (block-pred block))
+ (component-entry-p (unlist (block-pred block))))
"ENTRY")
((component-exit-p block)
"EXIT")
- (t (string (bblock-id block))))))
- (format t "BLOCK ~a:~%" (bblock-name block))
+ (t (string (block-id block))))))
+ (format t "BLOCK ~a:~%" (block-name block))
(do-nodes (node block)
- (print-node node))
- (when (singlep (bblock-succ block))
- (format t "GO ~a~%" (bblock-name (first (bblock-succ block)))))
+ (print-node node))
+ (when (singlep (block-succ block))
+ (format t "GO ~a~%" (block-name (first (block-succ block)))))
(terpri)))
(defun print-component (component &optional (stream *standard-output*))
(let ((*standard-output* stream))
(do-blocks (block component)
- (print-bblock block))))
-
-(defun check-ir-consistency (&optional (component *component*))
- (with-simple-restart (continue "Continue execution")
- (do-blocks (block component)
- (dolist (succ (bblock-succ block))
- (unless (find block (bblock-pred succ))
- (error "The block `~S' does not belong to the predecessors list of the its successor `~S'"
- (bblock-id block)
- (bblock-id succ))))
- (dolist (pred (bblock-pred block))
- (unless (find block (bblock-succ pred))
- (error "The block `~S' does not belong to the successors' list of its predecessor `~S'"
- (bblock-id block)
- (bblock-id pred)))))))
+ (print-block block))))
;;; Translate FORM into IR and print a textual repreresentation of the
;;; component.
-(defun describe-ir (form)
+(defun convert-toplevel-and-print (form &optional (complete t))
(with-component-compilation
- (ir-convert form (bblock-exit *bblock*) (make-lvar :id "$out"))
- (finish-component)
+ (ir-convert form (make-lvar :id "$out"))
+ (when complete (ir-complete))
(check-ir-consistency)
(print-component *component*)))
+(defmacro /ir (form)
+ `(convert-toplevel-and-print ',form))
+
+
+;;;; Primitives
+;;;;
+;;;; Primitive functions are a set of functions provided by the
+;;;; compiler. They cannot usually be written in terms of other
+;;;; functions. When the compiler tries to compile a function call, it
+;;;; looks for a primitive function firstly, and if it is found and
+;;;; the declarations allow it, a primitive call is inserted in the
+;;;; IR. The back-end of the compiler knows how to compile primitive
+;;;; calls.
+;;;;
+
+(defvar *primitive-function-table* nil)
+
+(defstruct primitive
+ name)
+
+(defmacro define-primitive (name args &body body)
+ (declare (ignore args body))
+ `(push (make-primitive :name ',name)
+ *primitive-function-table*))
+
+(defun find-primitive (name)
+ (find name *primitive-function-table* :key #'primitive-name))
+
+(define-primitive symbol-function (symbol))
+(define-primitive symbol-value (symbol))
+
;;; compiler.lisp ends here
projects / jscl.git / blobdiff