tweak

Generative-Program-Analysis · Oct 23, 2024 · d08a203 · d08a203
1 parent b6474eb
commit d08a203
Showing 1 changed file with 17 additions and 14 deletions.
diff --git a/src/main/scala/wasm/MiniWasm.scala b/src/main/scala/wasm/MiniWasm.scala
@@ -193,26 +193,29 @@ object Evaluator {
     }
   }
 
-  def evalDirectCall[Ans](rest: List[Instr],
-                          stack: List[Value],
-                          frame: Frame,
-                          kont: Cont[Ans],
-                          trail: List[Cont[Ans]],
-                          funcIndex: Int,
-                          isTail: Boolean): Ans = {
+  def evalCall[Ans](rest: List[Instr],
+                    stack: List[Value],
+                    frame: Frame,
+                    kont: Cont[Ans],
+                    trail: List[Cont[Ans]],
+                    funcIndex: Int,
+                    isTail: Boolean): Ans = {
     frame.module.funcs(funcIndex) match {
       case FuncDef(_, FuncBodyDef(ty, _, locals, body)) =>     
         val args = stack.take(ty.inps.size).reverse
         val newStack = stack.drop(ty.inps.size)
         val frameLocals = args ++ locals.map(zero(_))
         val newFrame = Frame(frame.module, ArrayBuffer(frameLocals: _*))
-        val newK: Cont[Ans] = (retStack) => eval(rest, retStack.take(ty.out.size) ++ newStack, frame, kont, trail)
-        // We push newK on the trail since function creates a new block to escape
-        // (more or less like `return`)
         if (isTail) 
+          // when tail call, share the continuation for returning with the callee
           eval(body, List(), newFrame, kont, List(kont))
-        else
-          eval(body, List(), newFrame, newK, List(newK))
+        else {
+          val restK: Cont[Ans] = (retStack) =>
+            eval(rest, retStack.take(ty.out.size) ++ newStack, frame, kont, trail)
+          // We make a new trail by `restK`, since function creates a new block to escape
+          // (more or less like `return`)
+          eval(body, List(), newFrame, restK, List(restK))
+        }
       case Import("console", "log", _) =>
             //println(s"[DEBUG] current stack: $stack")
             val I32V(v) :: newStack = stack
@@ -350,8 +353,8 @@ object Evaluator {
         val goto = if (cond < labels.length) labels(cond) else default
         trail(goto)(newStack)
       case Return => trail.last(stack)
-      case Call(f) => evalDirectCall(rest, stack, frame, kont, trail, f, false)
-      case ReturnCall(f) => evalDirectCall(rest, stack, frame, kont, trail, f, true)
+      case Call(f) => evalCall(rest, stack, frame, kont, trail, f, false)
+      case ReturnCall(f) => evalCall(rest, stack, frame, kont, trail, f, true)
       case _ =>
         println(inst)
         throw new Exception(s"instruction $inst not implemented")