--- a/progs/compile.scala Sun Oct 25 01:25:01 2020 +0000
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,274 +0,0 @@
-// A Small Compiler for the WHILE Language
-// (it does not use a parser nor lexer)
-
-
-// the abstract syntax trees
-abstract class Stmt
-abstract class AExp
-abstract class BExp
-type Block = List[Stmt]
-
-// statements
-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 Read(s: String) extends Stmt
-
-// arithmetic expressions
-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
-
-// boolean expressions
-case object True extends BExp
-case object False extends BExp
-case class Bop(o: String, a1: AExp, a2: AExp) extends BExp
-
-
-// compiler headers needed for the JVM
-// (contains methods for read and write)
-val beginning = """
-.class public XXX.XXX
-.super java/lang/Object
-
-.method public static write(I)V
- .limit locals 1
- .limit stack 2
- getstatic java/lang/System/out Ljava/io/PrintStream;
- iload 0
- invokevirtual java/io/PrintStream/println(I)V
- return
-.end method
-
-.method public static read()I
- .limit locals 10
- .limit stack 10
-
- ldc 0
- istore 1 ; this will hold our final integer
-Label1:
- getstatic java/lang/System/in Ljava/io/InputStream;
- invokevirtual java/io/InputStream/read()I
- istore 2
- iload 2
- ldc 10 ; the newline delimiter
- isub
- ifeq Label2
- iload 2
- ldc 32 ; the space delimiter
- isub
- ifeq Label2
-
- iload 2
- ldc 48 ; we have our digit in ASCII, have to subtract it from 48
- isub
- ldc 10
- iload 1
- imul
- iadd
- istore 1
- goto Label1
-Label2:
- ;when we come here we have our integer computed in local variable 1
- iload 1
- ireturn
-.end method
-
-.method public static main([Ljava/lang/String;)V
- .limit locals 200
- .limit stack 200
-
-; COMPILED CODE STARTS
-
-"""
-
-val ending = """
-; COMPILED CODE ENDS
- return
-
-.end method
-"""
-
-// Compiler functions
-
-
-// for generating new labels
-var counter = -1
-
-def Fresh(x: String) = {
- counter += 1
- x ++ "_" ++ counter.toString()
-}
-
-// convenient string interpolations
-// for instructions and labels
-import scala.language.implicitConversions
-import scala.language.reflectiveCalls
-
-implicit def sring_inters(sc: StringContext) = new {
- def i(args: Any*): String = " " ++ sc.s(args:_*) ++ "\n"
- def l(args: Any*): String = sc.s(args:_*) ++ ":\n"
-}
-
-// this allows us to write things like
-// i"add" and l"Label"
-
-
-// environments
-type Env = Map[String, Int]
-
-
-def compile_op(op: String) = op match {
- case "+" => i"iadd"
- case "-" => i"isub"
- case "*" => i"imul"
-}
-
-// arithmetic expression compilation
-def compile_aexp(a: AExp, env : Env) : String = a match {
- case Num(i) => i"ldc $i"
- case Var(s) => i"iload ${env(s)} \t\t; $s"
- case Aop(op, a1, a2) =>
- compile_aexp(a1, env) ++ compile_aexp(a2, env) ++ compile_op(op)
-}
-
-// boolean expression compilation
-// - the jump-label is for where to jump if the condition is not true
-def compile_bexp(b: BExp, env : Env, jmp: String) : String = b match {
- case True => ""
- case False => i"goto $jmp"
- case Bop("==", a1, a2) =>
- compile_aexp(a1, env) ++ compile_aexp(a2, env) ++ i"if_icmpne $jmp"
- case Bop("!=", a1, a2) =>
- compile_aexp(a1, env) ++ compile_aexp(a2, env) ++ i"if_icmpeq $jmp"
- case Bop("<", a1, a2) =>
- compile_aexp(a1, env) ++ compile_aexp(a2, env) ++ i"if_icmpge $jmp"
-}
-
-// statement compilation
-def compile_stmt(s: Stmt, env: Env) : (String, Env) = s match {
- case Skip => ("", env)
- case Assign(x, a) => {
- val index = env.getOrElse(x, env.keys.size)
- (compile_aexp(a, env) ++ i"istore $index \t\t; $x", env + (x -> index))
- }
- case If(b, bl1, bl2) => {
- val if_else = Fresh("If_else")
- val if_end = Fresh("If_end")
- val (instrs1, env1) = compile_block(bl1, env)
- val (instrs2, env2) = compile_block(bl2, env1)
- (compile_bexp(b, env, if_else) ++
- instrs1 ++
- i"goto $if_end" ++
- l"$if_else" ++
- instrs2 ++
- l"$if_end", env2)
- }
- case While(b, bl) => {
- val loop_begin = Fresh("Loop_begin")
- val loop_end = Fresh("Loop_end")
- val (instrs1, env1) = compile_block(bl, env)
- (l"$loop_begin" ++
- compile_bexp(b, env, loop_end) ++
- instrs1 ++
- i"goto $loop_begin" ++
- l"$loop_end", env1)
- }
- case Write(x) =>
- (i"iload ${env(x)} \t\t; $x" ++
- i"invokestatic XXX/XXX/write(I)V", env)
- case Read(x) => {
- val index = env.getOrElse(x, env.keys.size)
- (i"invokestatic XXX/XXX/read()I" ++
- i"istore $index \t\t; $x", env + (x -> index))
- }
-}
-
-// compilation of a block (i.e. list of instructions)
-def compile_block(bl: Block, env: Env) : (String, Env) = bl match {
- case Nil => ("", env)
- case s::bl => {
- val (instrs1, env1) = compile_stmt(s, env)
- val (instrs2, env2) = compile_block(bl, env1)
- (instrs1 ++ instrs2, env2)
- }
-}
-
-// main compilation function for blocks
-def compile(bl: Block, class_name: String) : String = {
- val instructions = compile_block(bl, Map.empty)._1
- (beginning ++ instructions ++ ending).replaceAllLiterally("XXX", class_name)
-}
-
-
-// compiling and running files
-//
-// JVM files can be assembled with
-//
-// java -jar jvm/jasmin-2.4/jasmin.jar fib.j
-//
-// and started with
-//
-// java fib/fib
-
-
-
-import scala.util._
-import scala.sys.process._
-import scala.io
-
-def compile_tofile(bl: Block, class_name: String) = {
- val output = compile(bl, class_name)
- val fw = new java.io.FileWriter(class_name + ".j")
- fw.write(output)
- fw.close()
-}
-
-def compile_all(bl: Block, class_name: String) : Unit = {
- compile_tofile(bl, class_name)
- println("compiled ")
- val test = ("java -jar jvm/jasmin-2.4/jasmin.jar " + class_name + ".j").!!
- println("assembled ")
-}
-
-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)
-}
-
-
-def compile_run(bl: Block, class_name: String) : Unit = {
- println("Start compilation")
- compile_all(bl, class_name)
- println("running")
- println("Time: " + time_needed(1, ("java " + class_name + "/" + class_name).!))
-}
-
-
-// Fibonacci numbers as a bare-bone test-case
-val fib_test =
- List(Assign("n", Num(9)), // n := 10;
- Assign("minus1",Num(0)), // minus1 := 0;
- Assign("minus2",Num(1)), // minus2 := 1;
- Assign("temp",Num(0)), // temp := 0;
- While(Bop("<",Num(0),Var("n")), // while n > 0 do {
- List(Assign("temp",Var("minus2")), // temp := minus2;
- Assign("minus2",Aop("+",Var("minus1"),Var("minus2"))),
- // minus2 := minus1 + minus2;
- Assign("minus1",Var("temp")), // minus1 := temp;
- Assign("n",Aop("-",Var("n"),Num(1))))), // n := n - 1 };
- Write("minus1")) // write minus1
-
-
-// the compiled file as string
-//
-//println(compile(fib_test, "fib"))
-
-
-compile_run(fib_test, "fib")
-
-