Test semanticdb performance

compiler/src/dotty/tools/dotc/config/ScalaSettings.scala

@@ -153,7 +153,7 @@ private sealed trait XSettings:
   val XverifySignatures: Setting[Boolean] = BooleanSetting("-Xverify-signatures", "Verify generic signatures in generated bytecode.")
   val XignoreScala2Macros: Setting[Boolean] = BooleanSetting("-Xignore-scala2-macros", "Ignore errors when compiling code that calls Scala2 macros, these will fail at runtime.")
   val XimportSuggestionTimeout: Setting[Int] = IntSetting("-Ximport-suggestion-timeout", "Timeout (in ms) for searching for import suggestions when errors are reported.", 8000)
-  val Xsemanticdb: Setting[Boolean] = BooleanSetting("-Xsemanticdb", "Store information in SemanticDB.", aliases = List("-Ysemanticdb"))
+  val Xsemanticdb: Setting[Boolean] = BooleanSetting("-Xsemanticdb", "Store information in SemanticDB.", aliases = List("-Ysemanticdb"), initialValue = true)
   val Xtarget: Setting[String] = ChoiceSetting("-Xtarget", "target", "Emit bytecode for the specified version of the Java platform. This might produce bytecode that will break at runtime. When on JDK 9+, consider -release as a safer alternative.", ScalaSettings.supportedTargetVersions, "", aliases = List("--Xtarget"))
   val XcheckMacros: Setting[Boolean] = BooleanSetting("-Xcheck-macros", "Check some invariants of macro generated code while expanding macros", aliases = List("--Xcheck-macros"))
 

compiler/src/dotty/tools/dotc/semanticdb/ConstantOps.scala

@@ -0,0 +1,25 @@
+package dotty.tools
+package dotc
+package semanticdb
+
+import dotty.tools.dotc.{semanticdb => s}
+
+import core.Contexts.Context
+import core.Constants._
+
+object ConstantOps:
+  extension (const: Constant)
+    def toSemanticConst(using Context): s.Constant = const.tag match {
+      case UnitTag => s.UnitConstant()
+      case BooleanTag => s.BooleanConstant(const.booleanValue)
+      case ByteTag => s.ByteConstant(const.byteValue)
+      case ShortTag => s.ShortConstant(const.shortValue)
+      case CharTag => s.CharConstant(const.charValue)
+      case IntTag => s.IntConstant(const.intValue)
+      case LongTag => s.LongConstant(const.longValue)
+      case FloatTag => s.FloatConstant(const.floatValue)
+      case DoubleTag => s.DoubleConstant(const.doubleValue)
+      case StringTag => s.StringConstant(const.stringValue)
+      case NullTag => s.NullConstant()
+      case _ => throw new Error(s"Constant ${const} can't be converted to Semanticdb Constant.")
+    }

compiler/src/dotty/tools/dotc/semanticdb/Descriptor.scala

@@ -0,0 +1,120 @@
+package dotty.tools.dotc.semanticdb
+
+import java.lang.System.{lineSeparator => EOL}
+import dotty.tools.dotc.semanticdb.{Descriptor => d}
+
+class DescriptorParser(s: String) {
+  var i = s.length
+  def fail() = {
+    val message = "invalid symbol format"
+    val caret = " " * i + "^"
+    sys.error(s"$message$EOL$s$EOL$caret")
+  }
+
+  val BOF = '\u0000'
+  val EOF = '\u001A'
+  var currChar = EOF
+  def readChar(): Char = {
+    if (i <= 0) {
+      if (i == 0) {
+        i -= 1
+        currChar = BOF
+        currChar
+      } else {
+        fail()
+      }
+    } else {
+      i -= 1
+      currChar = s(i)
+      currChar
+    }
+  }
+
+  def parseValue(): String = {
+    if (currChar == '`') {
+      val end = i
+      while (readChar() != '`') {}
+      readChar()
+      s.substring(i + 2, end)
+    } else {
+      val end = i + 1
+      if (!Character.isJavaIdentifierPart(currChar)) fail()
+      while (Character.isJavaIdentifierPart(readChar()) && currChar != BOF) {}
+      s.substring(i + 1, end)
+    }
+  }
+
+  def parseDisambiguator(): String = {
+    val end = i + 1
+    if (currChar != ')') fail()
+    while (readChar() != '(') {}
+    readChar()
+    s.substring(i + 1, end)
+  }
+
+  def parseDescriptor(): Descriptor = {
+    if (currChar == '.') {
+      readChar()
+      if (currChar == ')') {
+        val disambiguator = parseDisambiguator()
+        val value = parseValue()
+        d.Method(value, disambiguator)
+      } else {
+        d.Term(parseValue())
+      }
+    } else if (currChar == '#') {
+      readChar()
+      d.Type(parseValue())
+    } else if (currChar == '/') {
+      readChar()
+      d.Package(parseValue())
+    } else if (currChar == ')') {
+      readChar()
+      val value = parseValue()
+      if (currChar != '(') fail()
+      else readChar()
+      d.Parameter(value)
+    } else if (currChar == ']') {
+      readChar()
+      val value = parseValue()
+      if (currChar != '[') fail()
+      else readChar()
+      d.TypeParameter(value)
+    } else {
+      fail()
+    }
+  }
+
+  def entryPoint(): (Descriptor, String) = {
+    readChar()
+    val desc = parseDescriptor()
+    (desc, s.substring(0, i + 1))
+  }
+}
+
+object DescriptorParser {
+  def apply(symbol: String): (Descriptor, String) = {
+    val parser = new DescriptorParser(symbol)
+    parser.entryPoint()
+  }
+}
+
+sealed trait Descriptor {
+  def isNone: Boolean = this == d.None
+  def isTerm: Boolean = this.isInstanceOf[d.Term]
+  def isMethod: Boolean = this.isInstanceOf[d.Method]
+  def isType: Boolean = this.isInstanceOf[d.Type]
+  def isPackage: Boolean = this.isInstanceOf[d.Package]
+  def isParameter: Boolean = this.isInstanceOf[d.Parameter]
+  def isTypeParameter: Boolean = this.isInstanceOf[d.TypeParameter]
+  def value: String
+}
+object Descriptor {
+  case object None extends Descriptor { def value: String = "" }
+  final case class Term(value: String) extends Descriptor
+  final case class Method(value: String, disambiguator: String) extends Descriptor
+  final case class Type(value: String) extends Descriptor
+  final case class Package(value: String) extends Descriptor
+  final case class Parameter(value: String) extends Descriptor
+  final case class TypeParameter(value: String) extends Descriptor
+}