Ensure to escape characters before constructing JSON profile trace

compiler/src/dotty/tools/dotc/profile/JsonNameTransformer.scala

@@ -0,0 +1,46 @@
+package dotty.tools.dotc.profile
+
+import scala.annotation.internal.sharable
+
+// Based on NameTransformer but dedicated for JSON encoding rules
+object JsonNameTransformer {
+  private val nops = 128
+
+  @sharable private val op2code = new Array[String](nops)
+  private def enterOp(op: Char, code: String) = op2code(op.toInt) = code
+
+  enterOp('\"', "\\\"")
+  enterOp('\\', "\\\\")
+  // enterOp('/', "\\/") // optional, no need for escaping outside of html context
+  enterOp('\b', "\\b")
+  enterOp('\f', "\\f")
+  enterOp('\n', "\\n")
+  enterOp('\r', "\\r")
+  enterOp('\t', "\\t")
+
+  def encode(name: String): String = {
+    var buf: StringBuilder = null.asInstanceOf
+    val len = name.length
+    var i = 0
+    while (i < len) {
+      val c = name(i)
+      if (c < nops && (op2code(c.toInt) ne null)) {
+        if (buf eq null) {
+          buf = new StringBuilder()
+          buf.append(name.subSequence(0, i))
+        }
+        buf.append(op2code(c.toInt))
+      } else if (c <= 0x1F || c > 0x7F) {
+        if (buf eq null) {
+          buf = new StringBuilder()
+          buf.append(name.subSequence(0, i))
+        }
+        buf.append("\\u%04X".format(c.toInt))
+      } else if (buf ne null) {
+        buf.append(c)
+      }
+      i += 1
+    }
+    if (buf eq null) name else buf.toString
+  }
+}

compiler/src/dotty/tools/dotc/profile/Profiler.scala

@@ -273,7 +273,7 @@ private [profile] class RealProfiler(reporter : ProfileReporter)(using Context)
   override def beforePhase(phase: Phase): (TracedEventId, ProfileSnap) = {
     assert(mainThread eq Thread.currentThread())
     traceThreadSnapshotCounters()
-    val eventId = traceDurationStart(Category.Phase, phase.phaseName)
+    val eventId = traceDurationStart(Category.Phase, escapeSpecialChars(phase.phaseName))
     if (ctx.settings.YprofileRunGcBetweenPhases.value.contains(phase.toString))
       doGC()
     if (ctx.settings.YprofileExternalTool.value.contains(phase.toString)) {
@@ -287,7 +287,7 @@ private [profile] class RealProfiler(reporter : ProfileReporter)(using Context)
     assert(mainThread eq Thread.currentThread())
     if chromeTrace != null then
       traceThreadSnapshotCounters()
-      traceDurationStart(Category.File, unit.source.name)
+      traceDurationStart(Category.File, escapeSpecialChars(unit.source.name))
     else TracedEventId.Empty
   }
 
@@ -325,7 +325,7 @@ private [profile] class RealProfiler(reporter : ProfileReporter)(using Context)
     then EmptyCompletionEvent
     else
       val completionName = this.completionName(root, associatedFile)
-      val event = TracedEventId(associatedFile.name)
+      val event = TracedEventId(escapeSpecialChars(associatedFile.name))
       chromeTrace.traceDurationEventStart(Category.Completion.name, "↯", colour = "thread_state_sleeping")
       chromeTrace.traceDurationEventStart(Category.File.name, event)
       chromeTrace.traceDurationEventStart(Category.Completion.name, completionName)
@@ -350,8 +350,13 @@ private [profile] class RealProfiler(reporter : ProfileReporter)(using Context)
     if chromeTrace != null then
       chromeTrace.traceDurationEventEnd(category.name, event, colour)
 
-  private def symbolName(sym: Symbol): String = s"${sym.showKind} ${sym.showName}"
-  private def completionName(root: Symbol, associatedFile: AbstractFile): String =
+  private inline def escapeSpecialChars(value: String): String =
+    JsonNameTransformer.encode(value)
+
+  private def symbolName(sym: Symbol): String = escapeSpecialChars:
+    s"${sym.showKind} ${sym.showName}"
+
+  private def completionName(root: Symbol, associatedFile: AbstractFile): String = escapeSpecialChars:
     def isTopLevel = root.owner != NoSymbol && root.owner.is(Flags.Package)
     if root.is(Flags.Package) || isTopLevel
     then root.javaBinaryName

compiler/test/dotty/tools/DottyTest.scala

@@ -46,7 +46,7 @@ trait DottyTest extends ContextEscapeDetection {
 
   protected def defaultCompiler: Compiler = new Compiler()
 
-  private def compilerWithChecker(phase: String)(assertion: (tpd.Tree, Context) => Unit) = new Compiler {
+  protected def compilerWithChecker(phase: String)(assertion: (tpd.Tree, Context) => Unit) = new Compiler {
 
     private val baseCompiler = defaultCompiler
 

compiler/test/dotty/tools/dotc/profile/TraceNameManglingTest.scala

@@ -0,0 +1,133 @@
+package dotty.tools.dotc.profile
+
+import org.junit.Assert.*
+import org.junit.*
+
+import scala.annotation.tailrec
+import dotty.tools.DottyTest
+import dotty.tools.dotc.util.SourceFile
+import dotty.tools.dotc.core.Contexts.FreshContext
+import java.nio.file.Files
+import java.util.Locale
+
+class TraceNameManglingTest extends DottyTest {
+
+  override protected def initializeCtx(fc: FreshContext): Unit = {
+    super.initializeCtx(fc)
+    val tmpDir = Files.createTempDirectory("trace_name_mangling_test").nn
+    fc.setSetting(fc.settings.YprofileEnabled, true)
+    fc.setSetting(
+      fc.settings.YprofileTrace,
+      tmpDir.resolve("trace.json").nn.toAbsolutePath().toString()
+    )
+    fc.setSetting(
+      fc.settings.YprofileDestination,
+      tmpDir.resolve("profiler.out").nn.toAbsolutePath().toString()
+    )
+  }
+
+  @Test def escapeBackslashes(): Unit = {
+    val isWindows = sys.props("os.name").toLowerCase(Locale.ROOT) == "windows"
+    val filename = if isWindows then "/.scala" else "\\.scala"
+    checkTraceEvents(
+      """
+      |class /\ :
+      |  var /\ = ???
+      |object /\{
+      |  def /\ = ???
+      |}""".stripMargin,
+      filename = filename
+    )(
+      Set(
+        raw"class /\\",
+        raw"object /\\",
+        raw"method /\\",
+        raw"variable /\\",
+        raw"setter /\\_="
+      ).map(TraceEvent("typecheck", _))
+        ++ Set(
+          TraceEvent("file", if isWindows then "/.scala" else "\\\\.scala")
+        )
+    )
+  }
+
+  @Test def escapeDoubleQuotes(): Unit = {
+    val filename = "\"quoted\".scala"
+    checkTraceEvents(
+      """
+      |class `"QuotedClass"`:
+      |  var `"quotedVar"` = ???
+      |object `"QuotedObject"` {
+      |  def `"quotedMethod"` = ???
+      |}""".stripMargin,
+      filename = filename
+    ):
+      Set(
+        raw"class \"QuotedClass\"",
+        raw"object \"QuotedObject\"",
+        raw"method \"quotedMethod\"",
+        raw"variable \"quotedVar\""
+      ).map(TraceEvent("typecheck", _))
+        ++ Set(TraceEvent("file", "\\\"quoted\\\".scala"))
+  }
+  @Test def escapeNonAscii(): Unit = {
+    val filename = "unic😀de.scala"
+    checkTraceEvents(
+      """
+      |class ΩUnicodeClass:
+      |  var `中文Var` = ???
+      |object ΩUnicodeObject {
+      |  def 中文Method = ???
+      |}""".stripMargin,
+      filename = filename
+    ):
+      Set(
+        "class \\u03A9UnicodeClass",
+        "object \\u03A9UnicodeObject",
+        "method \\u4E2D\\u6587Method",
+        "variable \\u4E2D\\u6587Var"
+      ).map(TraceEvent("typecheck", _))
+        ++ Set(TraceEvent("file", "unic\\uD83D\\uDE00de.scala"))
+  }
+
+  case class TraceEvent(category: String, name: String)
+  private def compileWithTracer(
+      code: String,
+      filename: String,
+      afterPhase: String = "typer"
+  )(checkEvents: Seq[TraceEvent] => Unit) = {
+    val runCtx = locally:
+      val source = SourceFile.virtual(filename, code)
+      val c = compilerWithChecker(afterPhase) { (_, _) => () }
+      val run = c.newRun
+      run.compileSources(List(source))
+      run.runContext
+    assert(!runCtx.reporter.hasErrors, "compilation failed")
+    val outfile = ctx.settings.YprofileTrace.value
+    checkEvents:
+      scala.io.Source
+        .fromFile(outfile)
+        .getLines()
+        .collect:
+          case s"""${_}"cat":"${category}","name":${name},"ph":${_}""" =>
+            TraceEvent(category, name.stripPrefix("\"").stripSuffix("\""))
+        .distinct.toSeq
+  }
+
+  private def checkTraceEvents(code: String, filename: String = "test")(expected: Set[TraceEvent]): Unit = {
+    compileWithTracer(code, filename = filename, afterPhase = "typer"){ events =>
+      val missing = expected.diff(events.toSet)
+      def showFound = events
+        .groupBy(_.category)
+        .collect:
+          case (category, events)
+              if expected.exists(_.category == category) =>
+            s"- $category: [${events.map(_.name).mkString(", ")}]"
+        .mkString("\n")
+      assert(
+        missing.isEmpty,
+        s"""Missing ${missing.size} names [${missing.mkString(", ")}] in events, got:\n${showFound}"""
+      )
+    }
+  }
+}