src/main/wacc/backend/RuntimeError.scala

@@ -100,5 +100,23 @@ object RuntimeError {
 
   }
 
-  val all: Chain[RuntimeError] = Chain(ZeroDivError, BadChrError, NullPtrError, OverflowError)
+  case object OutOfBoundsError extends RuntimeError {
+
+    val strLabel = ".L._errOutOfBounds_str0"
+    val errStr = "fatal error: array index %d out of bounds"
+    val errLabel = ".L._errOutOfBounds"
+
+    def generateHandler: Chain[AsmLine] = Chain(
+      LabelDef(OutOfBoundsError.errLabel),
+      Pop(RSI), // le index
+      stackAlign,
+      Load(RDI, IndexAddress(RIP, LabelArg(OutOfBoundsError.strLabel))),
+      assemblyIR.Call(CLibFunc.PrintF),
+      Move(RDI, ImmediateVal(255)),
+      assemblyIR.Call(CLibFunc.Exit)
+    )
+  }
+
+  val all: Chain[RuntimeError] =
+    Chain(ZeroDivError, BadChrError, NullPtrError, OverflowError, OutOfBoundsError)
 }

src/main/wacc/backend/asmGenerator.scala

@@ -190,9 +190,13 @@ object asmGenerator {
           case ArrayElem(x, i) =>
             chain ++= evalExprOntoStack(rhs)
             chain ++= evalExprOntoStack(i)
+            chain += Compare(stack.head, ImmediateVal(0))
+            chain += Jump(LabelArg(OutOfBoundsError.errLabel), Cond.Less)
             chain ++= evalExprOntoStack(x)
             chain += stack.pop(RAX)
             chain += stack.pop(RCX)
+            // chain += Compare(RAX, RCX)
+            // chain += Jump(LabelArg(OutOfBoundsError.errLabel), Cond.GreaterEqual)
             chain += stack.pop(RDX)
 
             chain += Move(
@@ -294,6 +298,8 @@ object asmGenerator {
         chain ++= evalExprOntoStack(x)
         chain ++= evalExprOntoStack(i)
         chain += stack.pop(RCX)
+        chain += Compare(RCX, ImmediateVal(0))
+        chain += Jump(LabelArg(OutOfBoundsError.errLabel), Cond.Less)
         chain += stack.pop(RAX)
         // + Int because we store the length of the array at the start
         chain += Move(