Merge pull request scala#6653 from retronym/topic/names-names-names

Make ClassfileParser more efficient, lazy, and less cycle prone. [ci: last-only]

Author: retronym

project/VersionUtil.scala

@@ -5,6 +5,9 @@ import Keys._
 import java.util.{Date, Locale, Properties, TimeZone}
 import java.io.{File, FileInputStream}
 import java.text.SimpleDateFormat
+import java.time.Instant
+import java.time.format.DateTimeFormatter
+import java.time.temporal.{TemporalAccessor, TemporalQueries, TemporalQuery}
 
 import scala.collection.JavaConverters._
 import BuildSettings.autoImport._
@@ -71,8 +74,21 @@ object VersionUtil {
         val db = new FileRepositoryBuilder().findGitDir.build
         val head = db.resolve("HEAD")
         if (head eq null) {
-          log.info("No git HEAD commit found -- Using current date and 'unknown' SHA")
-          (new Date, "unknown")
+          import scala.sys.process._
+          try {
+            // Workaround lack of git worktree support in JGit https://bugs.eclipse.org/bugs/show_bug.cgi?id=477475
+            val sha = List("git", "rev-parse", "HEAD").!!.trim
+            val commitDateIso = List("git", "log", "-1", "--format=%cI", "HEAD").!!.trim
+            val date = java.util.Date.from(DateTimeFormatter.ISO_DATE_TIME.parse(commitDateIso, new TemporalQuery[Instant] {
+              override def queryFrom(temporal: TemporalAccessor): Instant = Instant.from(temporal)
+            }))
+            (date, sha.substring(0, 7))
+          } catch {
+            case ex: Exception =>
+              ex.printStackTrace()
+              log.info("No git HEAD commit found -- Using current date and 'unknown' SHA")
+              (new Date, "unknown")
+          }
         } else {
           val commit = new RevWalk(db).parseCommit(head)
           (new Date(commit.getCommitTime.toLong * 1000L), commit.getName.substring(0, 7))

src/compiler/scala/tools/nsc/Global.scala

@@ -1550,6 +1550,9 @@ class Global(var currentSettings: Settings, reporter0: LegacyReporter)
 
       reporting.summarizeErrors()
 
+      // val allNamesArray: Array[String] = allNames().map(_.toString).toArray.sorted
+      // allNamesArray.foreach(println(_))
+
       if (traceSymbolActivity)
         units map (_.body) foreach (traceSymbols recordSymbolsInTree _)
 
@@ -1577,6 +1580,8 @@ class Global(var currentSettings: Settings, reporter0: LegacyReporter)
 
       // Clear any sets or maps created via perRunCaches.
       perRunCaches.clearAll()
+      if (settings.verbose)
+        println("Name table size after compilation: " + nameTableSize + " chars")
     }
 
     /** Compile list of abstract files. */

src/compiler/scala/tools/nsc/symtab/SymbolLoaders.scala

@@ -13,12 +13,12 @@
 package scala.tools.nsc
 package symtab
 
-import classfile.ClassfileParser
+import classfile.{ClassfileParser, ReusableDataReader}
 import java.io.IOException
 import scala.reflect.internal.MissingRequirementError
 import scala.reflect.io.{AbstractFile, NoAbstractFile}
 import scala.tools.nsc.util.{ClassPath, ClassRepresentation}
-import scala.reflect.internal.util.StatisticsStatics
+import scala.reflect.internal.util.{ReusableInstance, StatisticsStatics}
 
 /** This class ...
  *
@@ -294,11 +294,11 @@ abstract class SymbolLoaders {
       }
     }
   }
-
+  private val classFileDataReader: ReusableInstance[ReusableDataReader] = new ReusableInstance[ReusableDataReader](() => new ReusableDataReader())
   class ClassfileLoader(val classfile: AbstractFile, clazz: ClassSymbol, module: ModuleSymbol) extends SymbolLoader with FlagAssigningCompleter {
     private object classfileParser extends {
       val symbolTable: SymbolLoaders.this.symbolTable.type = SymbolLoaders.this.symbolTable
-    } with ClassfileParser {
+    } with ClassfileParser(classFileDataReader) {
       override protected def lookupMemberAtTyperPhaseIfPossible(sym: Symbol, name: Name): Symbol =
         SymbolLoaders.this.lookupMemberAtTyperPhaseIfPossible(sym, name)
       /*

src/compiler/scala/tools/nsc/symtab/classfile/AbstractFileReader.scala

@@ -14,8 +14,10 @@ package scala.tools.nsc
 package symtab
 package classfile
 
-import java.lang.Float.intBitsToFloat
+import java.io.{ByteArrayInputStream, DataInputStream}
 import java.lang.Double.longBitsToDouble
+import java.lang.Float.intBitsToFloat
+import java.util
 
 import scala.tools.nsc.io.AbstractFile
 
@@ -25,11 +27,13 @@ import scala.tools.nsc.io.AbstractFile
  * @author Philippe Altherr
  * @version 1.0, 23/03/2004
  */
-class AbstractFileReader(val file: AbstractFile) {
+final class AbstractFileReader(buf0: Array[Byte]) extends DataReader {
+  private[this] var buf = buf0
 
-  /** the buffer containing the file
-   */
-  val buf: Array[Byte] = file.toByteArray
+  @deprecated("Use other constructor", "2.13.0")
+  def this(file: AbstractFile) {
+    this(file.toByteArray)
+  }
 
   /** the current input pointer
    */
@@ -62,17 +66,25 @@ class AbstractFileReader(val file: AbstractFile) {
     ((nextByte & 0xff) << 24) + ((nextByte & 0xff) << 16) +
     ((nextByte & 0xff) <<  8) +  (nextByte & 0xff)
 
+  /** extract a byte at position bp from buf
+   */
+  def getByte(mybp: Int): Byte =
+    buf(mybp)
+
+  def getBytes(mybp: Int, bytes: Array[Byte]): Unit = {
+    System.arraycopy(buf, mybp, bytes, 0, bytes.length)
+  }
 
   /** extract a character at position bp from buf
    */
   def getChar(mybp: Int): Char =
-    (((buf(mybp) & 0xff) << 8) + (buf(mybp+1) & 0xff)).toChar
+    (((getByte(mybp) & 0xff) << 8) + (getByte(mybp+1) & 0xff)).toChar
 
   /** extract an integer at position bp from buf
    */
   def getInt(mybp: Int): Int =
-    ((buf(mybp  ) & 0xff) << 24) + ((buf(mybp+1) & 0xff) << 16) +
-    ((buf(mybp+2) & 0xff) << 8) + (buf(mybp+3) & 0xff)
+    ((getByte(mybp) & 0xff) << 24) + ((getByte(mybp + 1) & 0xff) << 16) +
+    ((getByte(mybp + 2) & 0xff) << 8) + (getByte(mybp + 3) & 0xff)
 
   /** extract a long integer at position bp from buf
    */
@@ -87,8 +99,11 @@ class AbstractFileReader(val file: AbstractFile) {
    */
   def getDouble(mybp: Int): Double = longBitsToDouble(getLong(mybp))
 
+  def getUTF(mybp: Int, len: Int): String = {
+    new DataInputStream(new ByteArrayInputStream(buf, mybp, len)).readUTF
+  }
+
   /** skip next 'n' bytes
    */
   def skip(n: Int): Unit = { bp += n }
-
 }