Add cache for TASTy bytes

Author: mbovel

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

@@ -78,5 +78,5 @@ class JavaPlatform extends Platform {
     new ClassfileLoader(bin)
 
   def newTastyLoader(bin: AbstractFile)(using Context): SymbolLoader =
-    new TastyLoader(bin)
+    new TastyLoader(bin, ctx.cacheStore.tastyBytes)
 }

compiler/src/dotty/tools/dotc/core/CacheStores.scala

@@ -18,13 +18,15 @@ object CacheStores:
     def files: Cache[TermName, AbstractFile]
     def sources: Cache[AbstractFile, SourceFile]
     def classBytes: Cache[AbstractFile, Array[Byte]]
+    def tastyBytes: Cache[AbstractFile, Array[Byte]]
 
     override def toString: String =
       s"""CacheStore(
          |  classPaths = $classPaths,
          |  files = $files,
          |  sources = $sources
          |  classBytes = $classBytes
+         |  tastyBytes = $tastyBytes
          |)""".stripMargin
 
   /** Default, per-run cache store implementation. */
@@ -50,8 +52,8 @@ object CacheStores:
      */
     val sources = NoopCache()
 
-    /** By default, we do not cache class bytes across runs. */
+    /** By default, we do not cache class bytes. */
     val classBytes = NoopCache()
 
-    /** By default, we do not cache tasty loaders. */
-    val tastyLoaders = NoopCache()
+    /** By default, we do not cache tasty bytes. */
+    val tastyBytes = NoopCache()

compiler/src/dotty/tools/dotc/core/SymbolLoaders.scala

@@ -17,6 +17,7 @@ import NameOps.*
 import StdNames.*
 import classfile.{ClassfileParser, ClassfileTastyUUIDParser}
 import Decorators.*
+import Caches.Cache
 
 import util.Stats
 import reporting.trace
@@ -471,10 +472,11 @@ class ClassfileLoader(val classfile: AbstractFile) extends SymbolLoader {
     classfileParser.run()
 }
 
-class TastyLoader(val tastyFile: AbstractFile) extends SymbolLoader {
-  val isBestEffortTasty = tastyFile.hasBetastyExtension
+class TastyLoader(val tastyFile: AbstractFile, tastyBytesCache: Cache[AbstractFile, Array[Byte]]) extends SymbolLoader {
+  private val isBestEffortTasty = tastyFile.hasBetastyExtension
 
-  lazy val tastyBytes = tastyFile.toByteArray
+  private lazy val tastyBytes: Array[Byte] =
+    tastyBytesCache(tastyFile, tastyFile.toByteArray)
 
   private lazy val unpickler: tasty.DottyUnpickler =
     handleUnpicklingExceptions:

compiler/test/dotty/tools/TestCacheStore.scala

@@ -27,7 +27,10 @@ object TestCacheStore extends CacheStore:
 
   /** Cache class bytes across runs, except for classes in the `out` directory.
    *
-   *  Classes in the `out` directory are generated during tests, so we do not
-   *  want to cache them.
+   *  Files in the `out` directory are generated during tests, so we do not want
+   *  to cache them.
    */
   val classBytes = FilteringCache(SynchronizedMapCache(), !_.canonicalPath.startsWith(outDir))
+
+  /** Cache tasty bytes across runs, except for those in the `out` directory. */
+  val tastyBytes = FilteringCache(SynchronizedMapCache(), !_.canonicalPath.startsWith(outDir))