--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/progs/compile.scala Sat Jun 15 09:23:18 2013 -0400
@@ -0,0 +1,326 @@
+// A parser and evaluator for teh while language
+//
+import matcher._
+import parser._
+
+// some regular expressions
+val SYM = RANGE("ABCDEFGHIJKLMNOPQRSTUVXYZabcdefghijklmnopqrstuvwxyz_")
+val DIGIT = RANGE("0123456789")
+val ID = SEQ(SYM, STAR(ALT(SYM, DIGIT)))
+val NUM = PLUS(DIGIT)
+val KEYWORD = ALTS("skip", "while", "do", "if", "then", "else", "true", "false", "write")
+val SEMI: Rexp = ";"
+val OP: Rexp = ALTS(":=", "=", "-", "+", "*", "!=", "<", ">")
+val WHITESPACE = PLUS(RANGE(" \n"))
+val RPAREN: Rexp = ")"
+val LPAREN: Rexp = "("
+val BEGIN: Rexp = "{"
+val END: Rexp = "}"
+val COMMENT = SEQS("/*", NOT(SEQS(STAR(ALLC), "*/", STAR(ALLC))), "*/")
+
+// tokens for classifying the strings that have been recognised
+abstract class Token
+case object T_WHITESPACE extends Token
+case object T_COMMENT extends Token
+case object T_SEMI extends Token
+case object T_LPAREN extends Token
+case object T_RPAREN extends Token
+case object T_BEGIN extends Token
+case object T_END extends Token
+case class T_ID(s: String) extends Token
+case class T_OP(s: String) extends Token
+case class T_NUM(s: String) extends Token
+case class T_KWD(s: String) extends Token
+
+val lexing_rules: List[(Rexp, List[Char] => Token)] =
+ List((KEYWORD, (s) => T_KWD(s.mkString)),
+ (ID, (s) => T_ID(s.mkString)),
+ (OP, (s) => T_OP(s.mkString)),
+ (NUM, (s) => T_NUM(s.mkString)),
+ (SEMI, (s) => T_SEMI),
+ (LPAREN, (s) => T_LPAREN),
+ (RPAREN, (s) => T_RPAREN),
+ (BEGIN, (s) => T_BEGIN),
+ (END, (s) => T_END),
+ (WHITESPACE, (s) => T_WHITESPACE),
+ (COMMENT, (s) => T_COMMENT))
+
+// the tokenizer
+val Tok = Tokenizer(lexing_rules, List(T_WHITESPACE, T_COMMENT))
+
+// the abstract syntax trees
+abstract class Stmt
+abstract class AExp
+abstract class BExp
+type Block = List[Stmt]
+case object Skip extends Stmt
+case class If(a: BExp, bl1: Block, bl2: Block) extends Stmt
+case class While(b: BExp, bl: Block) extends Stmt
+case class Assign(s: String, a: AExp) extends Stmt
+case class Write(s: String) extends Stmt
+
+case class Var(s: String) extends AExp
+case class Num(i: Int) extends AExp
+case class Aop(o: String, a1: AExp, a2: AExp) extends AExp
+
+case object True extends BExp
+case object False extends BExp
+case class Relop(o: String, a1: AExp, a2: AExp) extends BExp
+
+// atomic parsers
+case class TokParser(tok: Token) extends Parser[List[Token], Token] {
+ def parse(ts: List[Token]) = ts match {
+ case t::ts if (t == tok) => Set((t, ts))
+ case _ => Set ()
+ }
+}
+implicit def token2tparser(t: Token) = TokParser(t)
+
+case object NumParser extends Parser[List[Token], Int] {
+ def parse(ts: List[Token]) = ts match {
+ case T_NUM(s)::ts => Set((s.toInt, ts))
+ case _ => Set ()
+ }
+}
+
+case object IdParser extends Parser[List[Token], String] {
+ def parse(ts: List[Token]) = ts match {
+ case T_ID(s)::ts => Set((s, ts))
+ case _ => Set ()
+ }
+}
+
+
+// arithmetic expressions
+lazy val AExp: Parser[List[Token], AExp] =
+ (T ~ T_OP("+") ~ AExp) ==> { case ((x, y), z) => Aop("+", x, z): AExp } ||
+ (T ~ T_OP("-") ~ AExp) ==> { case ((x, y), z) => Aop("-", x, z): AExp } || T
+lazy val T: Parser[List[Token], AExp] =
+ (F ~ T_OP("*") ~ T) ==> { case ((x, y), z) => Aop("*", x, z): AExp } || F
+lazy val F: Parser[List[Token], AExp] =
+ (T_LPAREN ~> AExp <~ T_RPAREN) ||
+ IdParser ==> Var ||
+ NumParser ==> Num
+
+// boolean expressions
+lazy val BExp: Parser[List[Token], BExp] =
+ (T_KWD("true") ==> ((_) => True: BExp)) ||
+ (T_KWD("false") ==> ((_) => False: BExp)) ||
+ (T_LPAREN ~> BExp <~ T_RPAREN) ||
+ (AExp ~ T_OP("=") ~ AExp) ==> { case ((x, y), z) => Relop("=", x, z): BExp } ||
+ (AExp ~ T_OP("!=") ~ AExp) ==> { case ((x, y), z) => Relop("!=", x, z): BExp } ||
+ (AExp ~ T_OP("<") ~ AExp) ==> { case ((x, y), z) => Relop("<", x, z): BExp } ||
+ (AExp ~ T_OP(">") ~ AExp) ==> { case ((x, y), z) => Relop("<", z, x): BExp }
+
+lazy val Stmt: Parser[List[Token], Stmt] =
+ (T_KWD("skip") ==> ((_) => Skip: Stmt)) ||
+ (IdParser ~ T_OP(":=") ~ AExp) ==> { case ((x, y), z) => Assign(x, z): Stmt } ||
+ (T_KWD("if") ~ BExp ~ T_KWD("then") ~ Block ~ T_KWD("else") ~ Block) ==>
+ { case (((((x,y),z),u),v),w) => If(y, u, w): Stmt } ||
+ (T_KWD("while") ~ BExp ~ T_KWD("do") ~ Block) ==> { case (((x, y), z), w) => While(y, w) } ||
+ (T_KWD("write") ~ IdParser) ==> { case (x, y) => Write(y) }
+
+lazy val Stmts: Parser[List[Token], Block] =
+ (Stmt ~ T_SEMI ~ Stmts) ==> { case ((x, y), z) => x :: z : Block } ||
+ (Stmt ==> ((s) => List(s) : Block))
+
+lazy val Block: Parser[List[Token], Block] =
+ (T_BEGIN ~> Stmts <~ T_END) ||
+ (Stmt ==> ((s) => List(s)))
+
+// compiler
+val beginning = """
+.class public XXX.XXX
+.super java/lang/Object
+
+.method public <init>()V
+ aload_0
+ invokenonvirtual java/lang/Object/<init>()V
+ return
+.end method
+
+.method public static write(I)V
+ .limit locals 5
+ .limit stack 5
+ iload 0
+ getstatic java/lang/System/out Ljava/io/PrintStream;
+ swap
+ invokevirtual java/io/PrintStream/println(I)V
+ return
+.end method
+
+
+.method public static main([Ljava/lang/String;)V
+ .limit locals 200
+ .limit stack 200
+
+"""
+
+val ending = """
+
+ return
+
+.end method
+"""
+
+// for generating new labels
+var counter = -1
+
+def Fresh(x: String) = {
+ counter += 1
+ x ++ "_" ++ counter.toString()
+}
+
+type Env = Map[String, String]
+type Instrs = List[String]
+
+def compile_aexp(a: AExp, env : Env) : Instrs = a match {
+ case Num(i) => List("ldc " + i.toString + "\n")
+ case Var(s) => List("iload " + env(s) + "\n")
+ case Aop("+", a1, a2) => compile_aexp(a1, env) ++ compile_aexp(a2, env) ++ List("iadd\n")
+ case Aop("-", a1, a2) => compile_aexp(a1, env) ++ compile_aexp(a2, env) ++ List("isub\n")
+ case Aop("*", a1, a2) => compile_aexp(a1, env) ++ compile_aexp(a2, env) ++ List("imul\n")
+}
+
+def compile_bexp(b: BExp, env : Env, jmp: String) : Instrs = b match {
+ case True => Nil
+ case False => List("goto " + jmp + "\n")
+ case Relop("=", a1, a2) =>
+ compile_aexp(a1, env) ++ compile_aexp(a2, env) ++ List("if_icmpne " + jmp + "\n")
+ case Relop("!=", a1, a2) =>
+ compile_aexp(a1, env) ++ compile_aexp(a2, env) ++ List("if_icmpeq " + jmp + "\n")
+ case Relop("<", a1, a2) =>
+ compile_aexp(a1, env) ++ compile_aexp(a2, env) ++ List("if_icmpge " + jmp + "\n")
+}
+
+
+def compile_stmt(s: Stmt, env: Env) : (Instrs, Env) = s match {
+ case Skip => (Nil, env)
+ case Assign(x, a) => {
+ val index = if (env.isDefinedAt(x)) env(x) else env.keys.size.toString
+ (compile_aexp(a, env) ++
+ List("istore " + index + "\n"), env + (x -> index))
+ }
+ case If(b, bl1, bl2) => {
+ val if_else = Fresh("If_else")
+ val if_end = Fresh("If_end")
+ val (instrs1, env1) = compile_bl(bl1, env)
+ val (instrs2, env2) = compile_bl(bl2, env1)
+ (compile_bexp(b, env, if_else) ++
+ instrs1 ++
+ List("goto " + if_end + "\n") ++
+ List("\n" + if_else + ":\n\n") ++
+ instrs2 ++
+ List("\n" + if_end + ":\n\n"), env2)
+ }
+ case While(b, bl) => {
+ val loop_begin = Fresh("Loop_begin")
+ val loop_end = Fresh("Loop_end")
+ val (instrs1, env1) = compile_bl(bl, env)
+ (List("\n" + loop_begin + ":\n\n") ++
+ compile_bexp(b, env, loop_end) ++
+ instrs1 ++
+ List("goto " + loop_begin + "\n") ++
+ List("\n" + loop_end + ":\n\n"), env1)
+ }
+ case Write(x) =>
+ (List("iload " + env(x) + "\n" + "invokestatic XXX/XXX/write(I)V\n"), env)
+}
+
+def compile_bl(bl: Block, env: Env) : (Instrs, Env) = bl match {
+ case Nil => (Nil, env)
+ case s::bl => {
+ val (instrs1, env1) = compile_stmt(s, env)
+ val (instrs2, env2) = compile_bl(bl, env1)
+ (instrs1 ++ instrs2, env2)
+ }
+}
+
+def compile(input: String) : String = {
+ val class_name = input.split('.')(0)
+ val tks = Tok.fromFile(input)
+ val ast = Stmts.parse_single(tks)
+ val instructions = compile_bl(ast, Map.empty)._1
+ (beginning ++ instructions.mkString ++ ending).replaceAllLiterally("XXX", class_name)
+}
+
+
+def compile_to(input: String, output: String) = {
+ val fw = new java.io.FileWriter(output)
+ fw.write(compile(input))
+ fw.close()
+}
+
+//
+val tks = Tok.fromString("x := x + 1")
+val ast = Stmt.parse_single(tks)
+println(compile_stmt(ast, Map("x" -> "n"))._1.mkString)
+
+
+
+//examples
+
+compile_to("loops.while", "loops.j")
+//compile_to("fib.while", "fib.j")
+
+
+// testing cases for time measurements
+
+def time_needed[T](i: Int, code: => T) = {
+ val start = System.nanoTime()
+ for (j <- 1 to i) code
+ val end = System.nanoTime()
+ (end - start)/(i * 1.0e9)
+}
+
+// for testing
+import scala.sys.process._
+
+val test_prog = """
+start := XXX;
+x := start;
+y := start;
+z := start;
+while 0 < x do {
+ while 0 < y do {
+ while 0 < z do {
+ z := z - 1
+ };
+ z := start;
+ y := y - 1
+ };
+ y := start;
+ x := x - 1
+};
+write x;
+write y;
+write z
+"""
+
+
+def compile_test(n: Int) : Unit = {
+ val class_name = "LOOP"
+ val tks = Tok.fromString(test_prog.replaceAllLiterally("XXX", n.toString))
+ val ast = Stmts.parse_single(tks)
+ val instructions = compile_bl(ast, Map.empty)._1
+ val assembly = (beginning ++ instructions.mkString ++ ending).replaceAllLiterally("XXX", class_name)
+ val fw = new java.io.FileWriter(class_name + ".j")
+ fw.write(assembly)
+ fw.close()
+ val test = ("java -jar jvm/jasmin-2.4/jasmin.jar " + class_name + ".j").!!
+ println(n + " " + time_needed(2, ("java " + class_name + "/" + class_name).!!))
+}
+
+List(1, 5000, 10000, 50000, 100000, 250000, 500000, 750000, 1000000).map(compile_test(_))
+
+
+
+// Javabyte code assmbler
+//
+// java -jar jvm/jasmin-2.4/jasmin.jar loops.j
+
+
+
+
+
+