feat: implement .loc, .file and .func debug directives

src/main/wacc/backend/LabelGenerator.scala

@@ -2,6 +2,7 @@ package wacc
 
 import scala.collection.mutable
 import cats.data.Chain
+import wacc.ast.Position
 
 private class LabelGenerator {
   import assemblyIR._
@@ -9,7 +10,9 @@ private class LabelGenerator {
   import asmGenerator.escaped
 
   private val strings = mutable.HashMap[String, String]()
+  private val files = mutable.HashMap[String, Int]()
   private var labelVal = -1
+  private var permittedFuncFile: Option[String] = None
 
   /** Get an arbitrary label. */
   def getLabel(): String = {
@@ -39,6 +42,25 @@ private class LabelGenerator {
   def getLabelArg(src: String, name: String): LabelArg =
     LabelArg(strings.getOrElseUpdate(src, s".L.$name.str${strings.size}"))
 
+  /** Get a debug directive for a file. */
+  def getDebugFile(file: java.io.File): Int =
+    files.getOrElseUpdate(file.getCanonicalPath, files.size)
+
+  /** Get a debug directive for a function. */
+  def getDebugFunc(pos: Position, name: String, label: LabelDef): Chain[AsmLine] = {
+    permittedFuncFile match {
+      case Some(f) if f != pos.file.getCanonicalPath => Chain.empty
+      case _ =>
+        permittedFuncFile = Some(pos.file.getCanonicalPath)
+        Chain(
+          LabelDef(name),
+          Directive.Location(getDebugFile(pos.file), pos.line, None),
+          Directive.Type(label, SymbolType.Function),
+          Directive.Func(name, label)
+        )
+    }
+  }
+
   /** Generate the assembly labels for constants that were labelled using the LabelGenerator. */
   def generateConstants: Chain[AsmLine] =
     strings.foldLeft(Chain.empty) { case (acc, (str, label)) =>
@@ -47,4 +69,10 @@ private class LabelGenerator {
         Directive.Asciz(str.escaped)
       )
     }
+
+  /** Generates debug directives that were created using the LabelGenerator. */
+  def generateDebug: Chain[AsmLine] =
+    files.foldLeft(Chain.empty) { case (acc, (file, no)) =>
+      acc :+ Directive.File(no, file)
+    }
 }

src/main/wacc/backend/asmGenerator.scala

@@ -36,11 +36,18 @@ object asmGenerator {
     given labelGenerator: LabelGenerator = LabelGenerator()
     val Program(funcs, main) = microProg
 
-    val progAsm = Chain(LabelDef("main")).concatAll(
+    val mainLabel = LabelDef("main")
+    val mainAsm = main.headOption match {
+      case Some(stmt) =>
+        labelGenerator.getDebugFunc(stmt.pos, "$main", mainLabel) + mainLabel
+      case None => Chain.one(mainLabel)
+    }
+    val progAsm = mainAsm.concatAll(
       funcPrologue(),
       main.foldMap(generateStmt(_)),
       Chain.one(Xor(RAX, RAX)),
       funcEpilogue(),
+      Chain(Directive.Size(mainLabel, SizeExpr.Relative(mainLabel)), Directive.EndFunc),
       generateBuiltInFuncs(),
       RuntimeError.all.foldMap(_.generate),
       funcs.foldMap(generateUserFunc(_))
@@ -51,6 +58,7 @@ object asmGenerator {
       Directive.Global("main"),
       Directive.RoData
     ).concatAll(
+      labelGenerator.generateDebug,
       labelGenerator.generateConstants,
       Chain.one(Directive.Text),
       progAsm
@@ -75,7 +83,10 @@ object asmGenerator {
     // Setup the stack with param 7 and up
     func.params.drop(argRegs.size).foreach(stack.reserve(_))
     stack.reserve(Size.Q64) // Reserve return pointer slot
-    var asm = Chain.one[AsmLine](labelGenerator.getLabelDef(func.name))
+    val funcLabel = labelGenerator.getLabelDef(func.name)
+    var asm = labelGenerator.getDebugFunc(func.pos, func.name.name, funcLabel)
+    val debugFunc = asm.size > 0
+    asm += funcLabel
     asm ++= funcPrologue()
     // Push the rest of params onto the stack for simplicity
     argRegs.zip(func.params).foreach { (reg, param) =>
@@ -83,6 +94,10 @@ object asmGenerator {
     }
     asm ++= func.body.foldMap(generateStmt(_))
     // No need for epilogue here since all user functions must return explicitly
+    if (debugFunc) {
+      asm += Directive.Size(funcLabel, SizeExpr.Relative(funcLabel))
+      asm += Directive.EndFunc
+    }
     asm
   }
 
@@ -159,8 +174,8 @@ object asmGenerator {
       stack: Stack,
       labelGenerator: LabelGenerator
   ): Chain[AsmLine] = {
-    var asm = Chain.empty[AsmLine]
-    asm += Comment(stmt.toString)
+    val fileNo = labelGenerator.getDebugFile(stmt.pos.file)
+    var asm = Chain.one[AsmLine](Directive.Location(fileNo, stmt.pos.line, None))
     stmt match {
       case Assign(lhs, rhs) =>
         lhs match {

src/main/wacc/backend/assemblyIR.scala

@@ -199,10 +199,15 @@ object assemblyIR {
   }
 
   enum Directive extends AsmLine {
-    case IntelSyntax, RoData, Text
+    case IntelSyntax, RoData, Text, EndFunc
     case Global(name: String)
     case Int(value: scala.Int)
     case Asciz(string: String)
+    case File(no: scala.Int, file: String)
+    case Location(fileNo: scala.Int, lineNo: scala.Int, colNo: Option[scala.Int])
+    case Func(name: String, label: LabelDef)
+    case Type(label: LabelDef, symbolType: SymbolType)
+    case Size(label: LabelDef, expr: SizeExpr)
 
     override def toString(): String = this match {
       case IntelSyntax   => ".intel_syntax noprefix"
@@ -211,6 +216,32 @@ object assemblyIR {
       case RoData        => ".section .rodata"
       case Int(value)    => s"\t.int $value"
       case Asciz(string) => s"\t.asciz \"$string\""
+      case File(no, file) => s".file $no \"${file}\""
+      case Location(fileNo, lineNo, colNo) =>
+        s"\t.loc $fileNo $lineNo" + colNo.map(c => s" $c").getOrElse("")
+      case Func(name, label) =>
+        s".func $name, ${label.name}"
+      case EndFunc => ".endfunc"
+      case Type(label, symbolType) =>
+        s".type ${label.name}, @${symbolType.toString}"
+      case Directive.Size(label, expr) =>
+        s".size ${label.name}, ${expr.toString}"
+    }
+  }
+
+  enum SymbolType {
+    case Function
+
+    override def toString(): String = this match {
+      case Function => "function"
+    }
+  }
+
+  enum SizeExpr {
+    case Relative(label: LabelDef)
+
+    override def toString(): String = this match {
+      case Relative(label) => s".-${label.name}"
     }
   }
 

src/main/wacc/frontend/microWacc.scala

@@ -92,6 +92,6 @@ object microWacc {
   case class Return(expr: Expr)(val pos: Position) extends Stmt
 
   // Program
-  case class FuncDecl(name: Ident, params: List[Ident], body: Chain[Stmt])
+  case class FuncDecl(name: Ident, params: List[Ident], body: Chain[Stmt])(val pos: Position)
   case class Program(funcs: Chain[FuncDecl], stmts: Chain[Stmt])
 }

src/main/wacc/frontend/typeChecker.scala

@@ -95,7 +95,7 @@ object typeChecker {
           microWacc.Ident(ident.v, ident.guid)(ty)
         },
         body
-      ),
+      )(func.pos),
       bodyErrors
     )
   }