feat: implement all runtime errors

Merge request lab2425_spring/WACC_37!32

Co-authored-by: Guy C <gc1523@ic.ac.uk>
Co-authored-by: Jonny <j.sinteix@gmail.com>
Co-authored-by: Connolly, Guy <guy.connolly23@imperial.ac.uk>
Co-authored-by: Gleb Koval <gleb@koval.net>

src/main/wacc/Main.scala

@@ -82,9 +82,11 @@ def compile(filename: String, outFile: Option[File] = None)(using
 def main(args: Array[String]): Unit =
   OParser.parse(cliParser, args, CliConfig()) match {
     case Some(config) =>
+      System.exit(
         compile(
           config.file.getAbsolutePath,
           outFile = Some(File(".", config.file.getName.stripSuffix(".wacc") + ".s"))
         )
+      )
     case None =>
   }

src/main/wacc/backend/RuntimeError.scala

@@ -0,0 +1,122 @@
+package wacc
+
+import cats.data.Chain
+import wacc.assemblyIR._
+
+sealed trait RuntimeError {
+  def strLabel: String
+  def errStr: String
+  def errLabel: String
+
+  def stringDef: Chain[AsmLine] = Chain(
+    Directive.Int(errStr.length),
+    LabelDef(strLabel),
+    Directive.Asciz(errStr)
+  )
+
+  def generateHandler: Chain[AsmLine]
+
+}
+
+object RuntimeError {
+
+  // TODO: Refactor to mitigate imports and redeclared vals perhaps
+
+  import wacc.asmGenerator.stackAlign
+  import assemblyIR.Size._
+  import assemblyIR.RegName._
+
+  // private val RAX = Register(Q64, AX)
+  // private val EAX = Register(D32, AX)
+  private val RDI = Register(Q64, DI)
+  private val RIP = Register(Q64, IP)
+  // private val RBP = Register(Q64, BP)
+  private val RSI = Register(Q64, SI)
+  // private val RDX = Register(Q64, DX)
+  // private val RCX = Register(Q64, CX)
+
+  case object ZeroDivError extends RuntimeError {
+    val strLabel = ".L._errDivZero_str0"
+    val errStr = "fatal error: division or modulo by zero"
+    val errLabel = ".L._errDivZero"
+
+    def generateHandler: Chain[AsmLine] = Chain(
+      LabelDef(ZeroDivError.errLabel),
+      stackAlign,
+      Load(RDI, IndexAddress(RIP, LabelArg(ZeroDivError.strLabel))),
+      assemblyIR.Call(CLibFunc.PrintF),
+      Move(RDI, ImmediateVal(-1)),
+      assemblyIR.Call(CLibFunc.Exit)
+    )
+
+  }
+
+  case object BadChrError extends RuntimeError {
+    val strLabel = ".L._errBadChr_str0"
+    val errStr = "fatal error: int %d is not an ASCII character 0-127"
+    val errLabel = ".L._errBadChr"
+
+    def generateHandler: Chain[AsmLine] = Chain(
+      LabelDef(BadChrError.errLabel),
+      Pop(RSI),
+      stackAlign,
+      Load(RDI, IndexAddress(RIP, LabelArg(BadChrError.strLabel))),
+      assemblyIR.Call(CLibFunc.PrintF),
+      Move(RDI, ImmediateVal(255)),
+      assemblyIR.Call(CLibFunc.Exit)
+    )
+
+  }
+
+  case object NullPtrError extends RuntimeError {
+    val strLabel = ".L._errNullPtr_str0"
+    val errStr = "fatal error: null pair dereferenced or freed"
+    val errLabel = ".L._errNullPtr"
+
+    def generateHandler: Chain[AsmLine] = Chain(
+      LabelDef(NullPtrError.errLabel),
+      stackAlign,
+      Load(RDI, IndexAddress(RIP, LabelArg(NullPtrError.strLabel))),
+      assemblyIR.Call(CLibFunc.PrintF),
+      Move(RDI, ImmediateVal(255)),
+      assemblyIR.Call(CLibFunc.Exit)
+    )
+
+  }
+
+  case object OverflowError extends RuntimeError {
+    val strLabel = ".L._errOverflow_str0"
+    val errStr = "fatal error: integer overflow or underflow occurred"
+    val errLabel = ".L._errOverflow"
+
+    def generateHandler: Chain[AsmLine] = Chain(
+      LabelDef(OverflowError.errLabel),
+      stackAlign,
+      Load(RDI, IndexAddress(RIP, LabelArg(OverflowError.strLabel))),
+      assemblyIR.Call(CLibFunc.PrintF),
+      Move(RDI, ImmediateVal(255)),
+      assemblyIR.Call(CLibFunc.Exit)
+    )
+
+  }
+
+  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),
+      Move(RSI, Register(Q64, CX)),
+      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

@@ -3,6 +3,7 @@ package wacc
 import scala.collection.mutable.ListBuffer
 import cats.data.Chain
 import cats.syntax.foldable._
+import wacc.RuntimeError._
 
 object asmGenerator {
   import microWacc._
@@ -13,24 +14,6 @@ object asmGenerator {
   import sizeExtensions._
   import lexer.escapedChars
 
-  abstract case class Error() {
-    def strLabel: String
-    def errStr: String
-    def errLabel: String
-
-    def stringDef: Chain[AsmLine] = Chain(
-      Directive.Int(errStr.size),
-      LabelDef(strLabel),
-      Directive.Asciz(errStr)
-    )
-  }
-  object zeroDivError extends Error {
-    // TODO: is this bad? Can we make an error case class/some other structure?
-    def strLabel = ".L._errDivZero_str0"
-    def errStr = "fatal error: division or modulo by zero"
-    def errLabel = ".L._errDivZero"
-  }
-
   private val RAX = Register(Q64, AX)
   private val EAX = Register(D32, AX)
   private val RDI = Register(Q64, DI)
@@ -39,6 +22,7 @@ object asmGenerator {
   private val RSI = Register(Q64, SI)
   private val RDX = Register(Q64, DX)
   private val RCX = Register(Q64, CX)
+  private val ECX = Register(D32, CX)
   private val argRegs = List(DI, SI, DX, CX, R8, R9)
 
   extension [T](chain: Chain[T])
@@ -80,7 +64,7 @@ object asmGenerator {
         LabelDef(s".L.str$i"),
         Directive.Asciz(str.escaped)
       )
-    } ++ zeroDivError.stringDef
+    } ++ RuntimeError.all.foldMap(_.stringDef)
 
     Chain(
       Directive.IntelSyntax,
@@ -161,7 +145,16 @@ object asmGenerator {
       // Out of memory check is optional
     )
 
-    chain ++= wrapBuiltinFunc(labelGenerator.getLabel(Builtin.Free), Chain.empty)
+    chain ++= wrapBuiltinFunc(
+      labelGenerator.getLabel(Builtin.Free),
+      Chain(
+        stackAlign,
+        Move(RDI, RAX),
+        Compare(RDI, ImmediateVal(0)),
+        Jump(LabelArg(NullPtrError.errLabel), Cond.Equal),
+        assemblyIR.Call(CLibFunc.Free)
+      )
+    )
 
     chain ++= wrapBuiltinFunc(
       labelGenerator.getLabel(Builtin.Read),
@@ -175,16 +168,7 @@ object asmGenerator {
       )
     )
 
-    chain ++= Chain(
+    chain ++= RuntimeError.all.foldMap(_.generateHandler)
-      // TODO can this be done with a call to generateStmt?
-      // Consider other error cases -> look to generalise
-      LabelDef(zeroDivError.errLabel),
-      stackAlign,
-      Load(RDI, IndexAddress(RIP, LabelArg(zeroDivError.strLabel))),
-      assemblyIR.Call(CLibFunc.PrintF),
-      Move(RDI, ImmediateVal(-1)),
-      assemblyIR.Call(CLibFunc.Exit)
-    )
 
     chain
   }
@@ -207,9 +191,17 @@ object asmGenerator {
           case ArrayElem(x, i) =>
             chain ++= evalExprOntoStack(rhs)
             chain ++= evalExprOntoStack(i)
+            chain += stack.pop(RCX)
+            chain += Compare(ECX, ImmediateVal(0))
+            chain += Jump(LabelArg(OutOfBoundsError.errLabel), Cond.Less)
+            chain += stack.push(Q64, RCX)
             chain ++= evalExprOntoStack(x)
             chain += stack.pop(RAX)
             chain += stack.pop(RCX)
+            chain += Compare(EAX, ImmediateVal(0))
+            chain += Jump(LabelArg(NullPtrError.errLabel), Cond.Equal)
+            chain += Compare(MemLocation(RAX, D32), ECX)
+            chain += Jump(LabelArg(OutOfBoundsError.errLabel), Cond.LessEqual)
             chain += stack.pop(RDX)
 
             chain += Move(
@@ -311,7 +303,13 @@ 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)
+        chain += Compare(EAX, ImmediateVal(0))
+        chain += Jump(LabelArg(NullPtrError.errLabel), Cond.Equal)
+        chain += Compare(MemLocation(RAX, D32), ECX)
+        chain += Jump(LabelArg(OutOfBoundsError.errLabel), Cond.LessEqual)
         // + Int because we store the length of the array at the start
         chain += Move(
           Register(x.ty.elemSize, AX),
@@ -321,13 +319,22 @@ object asmGenerator {
       case UnaryOp(x, op) =>
         chain ++= evalExprOntoStack(x)
         op match {
-          case UnaryOperator.Chr | UnaryOperator.Ord => // No op needed
+          case UnaryOperator.Chr =>
+            chain += Move(EAX, stack.head)
+            chain += And(EAX, ImmediateVal(-128))
+            chain += Compare(EAX, ImmediateVal(0))
+            chain += Jump(LabelArg(BadChrError.errLabel), Cond.NotEqual)
+          case UnaryOperator.Ord => // No op needed
           case UnaryOperator.Len =>
             chain += stack.pop(RAX)
             chain += Move(EAX, MemLocation(RAX, D32))
             chain += stack.push(D32, RAX)
           case UnaryOperator.Negate =>
-            chain += Negate(stack.head)
+            chain += Xor(EAX, EAX)
+            chain += Subtract(EAX, stack.head)
+            chain += Jump(LabelArg(OverflowError.errLabel), Cond.Overflow)
+            chain += stack.drop()
+            chain += stack.push(Q64, RAX)
           case UnaryOperator.Not =>
             chain += Xor(stack.head, ImmediateVal(1))
         }
@@ -341,24 +348,29 @@ object asmGenerator {
         op match {
           case BinaryOperator.Add =>
             chain += Add(stack.head, destX)
+            chain += Jump(LabelArg(OverflowError.errLabel), Cond.Overflow)
           case BinaryOperator.Sub =>
             chain += Subtract(destX, stack.head)
+            chain += Jump(LabelArg(OverflowError.errLabel), Cond.Overflow)
             chain += stack.drop()
             chain += stack.push(destX.size, RAX)
           case BinaryOperator.Mul =>
             chain += Multiply(destX, stack.head)
+            chain += Jump(LabelArg(OverflowError.errLabel), Cond.Overflow)
             chain += stack.drop()
             chain += stack.push(destX.size, RAX)
 
           case BinaryOperator.Div =>
             chain += Compare(stack.head, ImmediateVal(0))
-            chain += Jump(LabelArg(zeroDivError.errLabel), Cond.Equal)
+            chain += Jump(LabelArg(ZeroDivError.errLabel), Cond.Equal)
             chain += CDQ()
             chain += Divide(stack.head)
             chain += stack.drop()
             chain += stack.push(destX.size, RAX)
 
           case BinaryOperator.Mod =>
+            chain += Compare(stack.head, ImmediateVal(0))
+            chain += Jump(LabelArg(ZeroDivError.errLabel), Cond.Equal)
             chain += CDQ()
             chain += Divide(stack.head)
             chain += stack.drop()
@@ -444,7 +456,7 @@ object asmGenerator {
     chain
   }
 
-  private def stackAlign: AsmLine = And(Register(Q64, SP), ImmediateVal(-16))
+  def stackAlign: AsmLine = And(Register(Q64, SP), ImmediateVal(-16))
   private def zeroRest(dest: Dest, size: Size): Chain[AsmLine] = size match {
     case Q64 | D32 => Chain.empty
     case _         => Chain.one(And(dest, ImmediateVal((1 << (size.toInt * 8)) - 1)))

src/test/wacc/examples.scala

@@ -41,23 +41,7 @@ class ParallelExamplesSpec extends AnyFlatSpec with BeforeAndAfterAll {
       val inputLine =
         contents
           .find(_.matches("^# ?[Ii]nput:.*$"))
-          .map(line =>
+          .map(_.split(":").last.strip + "\n")
-            ("" :: line.split(":").last.strip.split(" ").toList)
-              .sliding(2)
-              .flatMap { arr =>
-                if (
-                    // First entry has no space in front
-                    arr(0) == "" ||
-                      // int followed by non-digit, space can be removed
-                      arr(0).toIntOption.nonEmpty && !arr(1)(0).isDigit ||
-                      // non-int followed by int, space can be removed
-                      !arr(0).last.isDigit && arr(1).toIntOption.nonEmpty
-                  )
-                then List(arr(1))
-                else List(" ", arr(1))
-              }
-              .mkString
-          )
           .getOrElse("")
       val outputLineIdx = contents.indexWhere(_.matches("^# ?[Oo]utput:.*$"))
       val expectedOutput =
@@ -92,7 +76,13 @@ class ParallelExamplesSpec extends AnyFlatSpec with BeforeAndAfterAll {
       )
 
       assert(process.exitValue == expectedExit)
-      assert(stdout.toString.replaceAll("0x[0-9a-f]+", "#addrs#") == expectedOutput)
+      assert(
+        stdout.toString
+          .replaceAll("0x[0-9a-f]+", "#addrs#")
+          .replaceAll("fatal error:.*", "#runtime_error#\u0000")
+          .takeWhile(_ != '\u0000')
+          == expectedOutput
+      )
     }
   }
 
@@ -117,7 +107,7 @@ class ParallelExamplesSpec extends AnyFlatSpec with BeforeAndAfterAll {
       // "^.*wacc-examples/valid/IO/IOLoop.wacc.*$",
       // "^.*wacc-examples/valid/IO/IOSequence.wacc.*$",
       // "^.*wacc-examples/valid/pairs.*$",
-      "^.*wacc-examples/valid/runtimeErr.*$",
+      //"^.*wacc-examples/valid/runtimeErr.*$",
       // "^.*wacc-examples/valid/scope.*$",
       // "^.*wacc-examples/valid/sequence.*$",
       // "^.*wacc-examples/valid/variables.*$",