refactor: use LabelGenerator for RuntimeErrors

src/main/wacc/backend/LabelGenerator.scala

@@ -0,0 +1,46 @@
+package wacc
+
+import scala.collection.mutable
+import cats.data.Chain
+
+private class LabelGenerator {
+  import assemblyIR._
+  import microWacc.{CallTarget, Ident, Builtin}
+  import asmGenerator.escaped
+
+  private val strings = mutable.HashMap[String, String]()
+  private var labelVal = -1
+
+  /** Get an arbitrary label. */
+  def getLabel(): String = {
+    labelVal += 1
+    s".L$labelVal"
+  }
+
+  /** Get a named label for a function. */
+  def getLabel(target: CallTarget): String = target match {
+    case Ident(v, _)   => s"wacc_$v"
+    case Builtin(name) => s"_$name"
+  }
+
+  /** Get a named label for an error. */
+  def getLabel(target: RuntimeError): String =
+    s".L.${target.name}"
+
+  /** Get an arbitrary label for a string. */
+  def getLabel(str: String): String =
+    strings.getOrElseUpdate(str, s".L.str${strings.size}")
+
+  /** Get a named label for a string. */
+  def getLabel(src: String, name: String): String =
+    strings.getOrElseUpdate(src, s".L.$name.str${strings.size}")
+
+  /** Generate the assembly labels for constants that were labelled using the LabelGenerator. */
+  def generateConstants: Chain[AsmLine] =
+    strings.foldLeft(Chain.empty) { case (acc, (str, label)) =>
+      acc ++ Chain(
+        LabelDef(label),
+        Directive.Asciz(str.escaped)
+      )
+    }
+}

src/main/wacc/backend/RuntimeError.scala

@@ -4,18 +4,16 @@ import cats.data.Chain
 import wacc.assemblyIR._
 
 sealed trait RuntimeError {
-  def strLabel: String
+  val name: String
-  def errStr: String
+  protected val errStr: String
-  def errLabel: String
 
-  def stringDef: Chain[AsmLine] = Chain(
+  protected def getErrLabel(using labelGenerator: LabelGenerator): String =
-    Directive.Int(errStr.length),
+    labelGenerator.getLabel(errStr, name = name)
-    LabelDef(strLabel),
-    Directive.Asciz(errStr)
-  )
 
-  def generateHandler: Chain[AsmLine]
+  protected def generateHandler(using labelGenerator: LabelGenerator): Chain[AsmLine]
 
+  def generate(using labelGenerator: LabelGenerator): Chain[AsmLine] =
+    LabelDef(labelGenerator.getLabel(this)) +: generateHandler
 }
 
 object RuntimeError {
@@ -36,14 +34,12 @@ object RuntimeError {
   // private val RCX = Register(Q64, CX)
 
   case object ZeroDivError extends RuntimeError {
-    val strLabel = ".L._errDivZero_str0"
+    val name = "errDivZero"
-    val errStr = "fatal error: division or modulo by zero"
+    protected val errStr = "fatal error: division or modulo by zero"
-    val errLabel = ".L._errDivZero"
 
-    def generateHandler: Chain[AsmLine] = Chain(
+    protected def generateHandler(using labelGenerator: LabelGenerator): Chain[AsmLine] = Chain(
-      LabelDef(ZeroDivError.errLabel),
       stackAlign,
-      Load(RDI, IndexAddress(RIP, LabelArg(ZeroDivError.strLabel))),
+      Load(RDI, IndexAddress(RIP, LabelArg(getErrLabel))),
       assemblyIR.Call(CLibFunc.PrintF),
       Move(RDI, ImmediateVal(-1)),
       assemblyIR.Call(CLibFunc.Exit)
@@ -52,15 +48,13 @@ object RuntimeError {
   }
 
   case object BadChrError extends RuntimeError {
-    val strLabel = ".L._errBadChr_str0"
+    val name = "errBadChr"
-    val errStr = "fatal error: int %d is not an ASCII character 0-127"
+    protected val errStr = "fatal error: int %d is not an ASCII character 0-127"
-    val errLabel = ".L._errBadChr"
 
-    def generateHandler: Chain[AsmLine] = Chain(
+    protected def generateHandler(using labelGenerator: LabelGenerator): Chain[AsmLine] = Chain(
-      LabelDef(BadChrError.errLabel),
       Pop(RSI),
       stackAlign,
-      Load(RDI, IndexAddress(RIP, LabelArg(BadChrError.strLabel))),
+      Load(RDI, IndexAddress(RIP, LabelArg(getErrLabel))),
       assemblyIR.Call(CLibFunc.PrintF),
       Move(RDI, ImmediateVal(255)),
       assemblyIR.Call(CLibFunc.Exit)
@@ -69,14 +63,12 @@ object RuntimeError {
   }
 
   case object NullPtrError extends RuntimeError {
-    val strLabel = ".L._errNullPtr_str0"
+    val name = "errNullPtr"
-    val errStr = "fatal error: null pair dereferenced or freed"
+    protected val errStr = "fatal error: null pair dereferenced or freed"
-    val errLabel = ".L._errNullPtr"
 
-    def generateHandler: Chain[AsmLine] = Chain(
+    protected def generateHandler(using labelGenerator: LabelGenerator): Chain[AsmLine] = Chain(
-      LabelDef(NullPtrError.errLabel),
       stackAlign,
-      Load(RDI, IndexAddress(RIP, LabelArg(NullPtrError.strLabel))),
+      Load(RDI, IndexAddress(RIP, LabelArg(getErrLabel))),
       assemblyIR.Call(CLibFunc.PrintF),
       Move(RDI, ImmediateVal(255)),
       assemblyIR.Call(CLibFunc.Exit)
@@ -85,14 +77,12 @@ object RuntimeError {
   }
 
   case object OverflowError extends RuntimeError {
-    val strLabel = ".L._errOverflow_str0"
+    val name = "errOverflow"
-    val errStr = "fatal error: integer overflow or underflow occurred"
+    protected val errStr = "fatal error: integer overflow or underflow occurred"
-    val errLabel = ".L._errOverflow"
 
-    def generateHandler: Chain[AsmLine] = Chain(
+    protected def generateHandler(using labelGenerator: LabelGenerator): Chain[AsmLine] = Chain(
-      LabelDef(OverflowError.errLabel),
       stackAlign,
-      Load(RDI, IndexAddress(RIP, LabelArg(OverflowError.strLabel))),
+      Load(RDI, IndexAddress(RIP, LabelArg(getErrLabel))),
       assemblyIR.Call(CLibFunc.PrintF),
       Move(RDI, ImmediateVal(255)),
       assemblyIR.Call(CLibFunc.Exit)
@@ -101,16 +91,13 @@ object RuntimeError {
   }
 
   case object OutOfBoundsError extends RuntimeError {
+    val name = "errOutOfBounds"
+    protected val errStr = "fatal error: array index %d out of bounds"
 
-    val strLabel = ".L._errOutOfBounds_str0"
+    protected def generateHandler(using labelGenerator: LabelGenerator): Chain[AsmLine] = Chain(
-    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))),
+      Load(RDI, IndexAddress(RIP, LabelArg(getErrLabel))),
       assemblyIR.Call(CLibFunc.PrintF),
       Move(RDI, ImmediateVal(255)),
       assemblyIR.Call(CLibFunc.Exit)

src/main/wacc/backend/asmGenerator.scala

@@ -1,6 +1,5 @@
 package wacc
 
-import scala.collection.mutable
 import cats.data.Chain
 import cats.syntax.foldable._
 import wacc.RuntimeError._
@@ -31,30 +30,6 @@ object asmGenerator {
     def concatAll(chains: Chain[T]*): Chain[T] =
       chains.foldLeft(chain)(_ ++ _)
 
-  private class LabelGenerator {
-    private val strings = mutable.HashMap[String, String]()
-    private var labelVal = -1
-    def getLabel(): String = {
-      labelVal += 1
-      s".L$labelVal"
-    }
-    def getLabel(target: CallTarget): String = target match {
-      case Ident(v, _)   => s"wacc_$v"
-      case Builtin(name) => s"_$name"
-    }
-    def getLabel(str: String): String =
-      strings.getOrElseUpdate(str, s".L.str${strings.size}")
-
-    def generateConstants: Chain[AsmLine] =
-      strings.foldLeft(Chain.empty) { case (acc, (str, label)) =>
-        acc ++ Chain(
-          Directive.Int(str.size),
-          LabelDef(label),
-          Directive.Asciz(str.escaped)
-        )
-      }
-  }
-
   def generateAsm(microProg: Program): Chain[AsmLine] = {
     given stack: Stack = Stack()
     given labelGenerator: LabelGenerator = LabelGenerator()
@@ -66,6 +41,7 @@ object asmGenerator {
       Chain.one(Xor(RAX, RAX)),
       funcEpilogue(),
       generateBuiltInFuncs(),
+      RuntimeError.all.foldMap(_.generate),
       funcs.foldMap(generateUserFunc(_))
     )
 
@@ -75,7 +51,6 @@ object asmGenerator {
       Directive.RoData
     ).concatAll(
       labelGenerator.generateConstants,
-      RuntimeError.all.foldMap(_.stringDef),
       Chain.one(Directive.Text),
       progAsm
     )
@@ -154,7 +129,7 @@ object asmGenerator {
         stackAlign,
         Move(RDI, RAX),
         Compare(RDI, ImmediateVal(0)),
-        Jump(LabelArg(NullPtrError.errLabel), Cond.Equal),
+        Jump(LabelArg(labelGenerator.getLabel(NullPtrError)), Cond.Equal),
         assemblyIR.Call(CLibFunc.Free)
       )
     )
@@ -171,8 +146,6 @@ object asmGenerator {
       )
     )
 
-    chain ++= RuntimeError.all.foldMap(_.generateHandler)
-
     chain
   }
 
@@ -181,7 +154,6 @@ object asmGenerator {
       labelGenerator: LabelGenerator
   ): Chain[AsmLine] = {
     var chain = Chain.empty[AsmLine]
-    chain += Comment(stmt.toString)
     stmt match {
       case Assign(lhs, rhs) =>
         lhs match {
@@ -195,15 +167,15 @@ object asmGenerator {
             chain ++= evalExprOntoStack(i)
             chain += stack.pop(RCX)
             chain += Compare(ECX, ImmediateVal(0))
-            chain += Jump(LabelArg(OutOfBoundsError.errLabel), Cond.Less)
+            chain += Jump(LabelArg(labelGenerator.getLabel(OutOfBoundsError)), 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 += Jump(LabelArg(labelGenerator.getLabel(NullPtrError)), Cond.Equal)
             chain += Compare(MemLocation(RAX, D32), ECX)
-            chain += Jump(LabelArg(OutOfBoundsError.errLabel), Cond.LessEqual)
+            chain += Jump(LabelArg(labelGenerator.getLabel(OutOfBoundsError)), Cond.LessEqual)
             chain += stack.pop(RDX)
 
             chain += Move(
@@ -305,12 +277,12 @@ object asmGenerator {
         chain ++= evalExprOntoStack(i)
         chain += stack.pop(RCX)
         chain += Compare(RCX, ImmediateVal(0))
-        chain += Jump(LabelArg(OutOfBoundsError.errLabel), Cond.Less)
+        chain += Jump(LabelArg(labelGenerator.getLabel(OutOfBoundsError)), Cond.Less)
         chain += stack.pop(RAX)
         chain += Compare(EAX, ImmediateVal(0))
-        chain += Jump(LabelArg(NullPtrError.errLabel), Cond.Equal)
+        chain += Jump(LabelArg(labelGenerator.getLabel(NullPtrError)), Cond.Equal)
         chain += Compare(MemLocation(RAX, D32), ECX)
-        chain += Jump(LabelArg(OutOfBoundsError.errLabel), Cond.LessEqual)
+        chain += Jump(LabelArg(labelGenerator.getLabel(OutOfBoundsError)), Cond.LessEqual)
         // + Int because we store the length of the array at the start
         chain += Move(
           Register(x.ty.elemSize, AX),
@@ -324,7 +296,7 @@ object asmGenerator {
             chain += Move(EAX, stack.head)
             chain += And(EAX, ImmediateVal(-128))
             chain += Compare(EAX, ImmediateVal(0))
-            chain += Jump(LabelArg(BadChrError.errLabel), Cond.NotEqual)
+            chain += Jump(LabelArg(labelGenerator.getLabel(BadChrError)), Cond.NotEqual)
           case UnaryOperator.Ord => // No op needed
           case UnaryOperator.Len =>
             chain += stack.pop(RAX)
@@ -333,7 +305,7 @@ object asmGenerator {
           case UnaryOperator.Negate =>
             chain += Xor(EAX, EAX)
             chain += Subtract(EAX, stack.head)
-            chain += Jump(LabelArg(OverflowError.errLabel), Cond.Overflow)
+            chain += Jump(LabelArg(labelGenerator.getLabel(OverflowError)), Cond.Overflow)
             chain += stack.drop()
             chain += stack.push(Q64, RAX)
           case UnaryOperator.Not =>
@@ -349,21 +321,21 @@ object asmGenerator {
         op match {
           case BinaryOperator.Add =>
             chain += Add(stack.head, destX)
-            chain += Jump(LabelArg(OverflowError.errLabel), Cond.Overflow)
+            chain += Jump(LabelArg(labelGenerator.getLabel(OverflowError)), Cond.Overflow)
           case BinaryOperator.Sub =>
             chain += Subtract(destX, stack.head)
-            chain += Jump(LabelArg(OverflowError.errLabel), Cond.Overflow)
+            chain += Jump(LabelArg(labelGenerator.getLabel(OverflowError)), 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 += Jump(LabelArg(labelGenerator.getLabel(OverflowError)), 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(labelGenerator.getLabel(ZeroDivError)), Cond.Equal)
             chain += CDQ()
             chain += Divide(stack.head)
             chain += stack.drop()
@@ -371,7 +343,7 @@ object asmGenerator {
 
           case BinaryOperator.Mod =>
             chain += Compare(stack.head, ImmediateVal(0))
-            chain += Jump(LabelArg(ZeroDivError.errLabel), Cond.Equal)
+            chain += Jump(LabelArg(labelGenerator.getLabel(ZeroDivError)), Cond.Equal)
             chain += CDQ()
             chain += Divide(stack.head)
             chain += stack.drop()
@@ -470,7 +442,7 @@ object asmGenerator {
 
   private val escapedCharsMapping = escapedChars.map { case (k, v) => v -> s"\\$k" }
   extension (s: String) {
-    private def escaped: String =
+    def escaped: String =
       s.flatMap(c => escapedCharsMapping.getOrElse(c, c.toString))
   }
 }

src/main/wacc/backend/assemblyIR.scala

@@ -199,8 +199,8 @@ object assemblyIR {
       case Global(name)  => s".globl $name"
       case Text          => ".text"
       case RoData        => ".section .rodata"
-      case Int(value)    => s".int $value"
+      case Int(value)    => s"\t.int $value"
-      case Asciz(string) => s".asciz \"$string\""
+      case Asciz(string) => s"\t.asciz \"$string\""
     }
   }