From 40b200a3e545fab64f97b0e66158e88967b24c79 Mon Sep 17 00:00:00 2001
From: Nicolas Stucki <nicolas.stucki@gmail.com>
Date: Thu, 17 May 2018 08:23:22 +0200
Subject: [PATCH] Pickle quotes directly as expressions in TASTY

* We avoid having to do owner changes after unpickling
* The pickled code is slightly smaller
---
 .../dotc/core/quoted/PickledQuotes.scala      | 34 +++----------------
 .../dotc/core/tasty/DottyUnpickler.scala      |  3 ++
 .../tools/dotc/core/tasty/TreeUnpickler.scala |  9 ++++-
 tests/run-with-compiler/quote-owners-2.check  | 14 ++++++++
 tests/run-with-compiler/quote-owners-2.scala  | 25 ++++++++++++++
 tests/run-with-compiler/quote-owners.check    |  9 +++++
 tests/run-with-compiler/quote-owners.scala    | 22 ++++++++++++
 tests/run-with-compiler/quote-run-large.scala |  5 +++
 8 files changed, 90 insertions(+), 31 deletions(-)
 create mode 100644 tests/run-with-compiler/quote-owners-2.check
 create mode 100644 tests/run-with-compiler/quote-owners-2.scala
 create mode 100644 tests/run-with-compiler/quote-owners.check
 create mode 100644 tests/run-with-compiler/quote-owners.scala

diff --git a/compiler/src/dotty/tools/dotc/core/quoted/PickledQuotes.scala b/compiler/src/dotty/tools/dotc/core/quoted/PickledQuotes.scala
index 45fed5697fc7..717dc343e201 100644
--- a/compiler/src/dotty/tools/dotc/core/quoted/PickledQuotes.scala
+++ b/compiler/src/dotty/tools/dotc/core/quoted/PickledQuotes.scala
@@ -46,8 +46,7 @@ object PickledQuotes {
     if (ctx.reporter.hasErrors) Nil
     else {
       assert(!tree.isInstanceOf[Hole]) // Should not be pickled as it represents `'(~x)` which should be optimized to `x`
-      val encapsulated = encapsulateQuote(tree)
-      val pickled = pickle(encapsulated)
+      val pickled = pickle(tree)
       TastyString.pickle(pickled)
     }
   }
@@ -75,37 +74,13 @@ object PickledQuotes {
   /** Unpickle the tree contained in the TastyExpr */
   private def unpickleExpr(expr: TastyExpr[_])(implicit ctx: Context): Tree = {
     val tastyBytes = TastyString.unpickle(expr.tasty)
-    val unpickled = unpickle(tastyBytes, expr.args)
-    unpickled match {
-      case PackageDef(_, (vdef: ValDef) :: Nil) =>
-        vdef.rhs.changeOwner(vdef.symbol, ctx.owner)
-    }
+    unpickle(tastyBytes, expr.args)
   }
 
   /** Unpickle the tree contained in the TastyType */
   private def unpickleType(ttpe: TastyType[_])(implicit ctx: Context): Tree = {
     val tastyBytes = TastyString.unpickle(ttpe.tasty)
-    val unpickled = unpickle(tastyBytes, ttpe.args)
-    unpickled match {
-      case PackageDef(_, (vdef: ValDef) :: Nil) =>
-        vdef.rhs.asInstanceOf[TypeApply].args.head
-          .changeOwner(vdef.symbol, ctx.owner)
-    }
-  }
-
-  /** Encapsulate the tree in a top level `val` or `type`
-   *    `<tree>` ==> `package _root_ { val $quote: Any = <tree> }`
-   *    or
-   *    `<type tree>` ==> `package _root_ { val $typeQuote: Any = null.asInstanceOf[<tree>] }`
-   */
-  private def encapsulateQuote(tree: Tree)(implicit ctx: Context): Tree = {
-    val name = (if (tree.isTerm) "$quote" else "$typeQuote").toTermName
-    val sym = ctx.newSymbol(ctx.owner, name, Synthetic, defn.AnyType, coord = tree.pos)
-    val encoded =
-      if (tree.isTerm) tree
-      else Literal(Constant(null)).select(nme.asInstanceOf_).appliedToTypeTrees(tree :: Nil)
-    val quoted = ValDef(sym, encoded).withPos(tree.pos)
-    PackageDef(ref(defn.RootPackage).asInstanceOf[Ident], quoted :: Nil).withPos(tree.pos)
+    unpickle(tastyBytes, ttpe.args)
   }
 
   // TASTY picklingtests/pos/quoteTest.scala
@@ -135,8 +110,7 @@ object PickledQuotes {
   /** Unpickle TASTY bytes into it's tree */
   private def unpickle(bytes: Array[Byte], splices: Seq[Any])(implicit ctx: Context): Tree = {
     val unpickler = new TastyUnpickler(bytes, splices)
-    unpickler.enter(roots = Set(defn.RootPackage))
-    val tree = unpickler.tree
+    val tree = unpickler.unpickleExpr()
     if (pickling ne noPrinter) {
       println(i"**** unpickled quote for \n${tree.show}")
       new TastyPrinter(bytes).printContents()
diff --git a/compiler/src/dotty/tools/dotc/core/tasty/DottyUnpickler.scala b/compiler/src/dotty/tools/dotc/core/tasty/DottyUnpickler.scala
index 29ae7cca14a7..5dc92ee916df 100644
--- a/compiler/src/dotty/tools/dotc/core/tasty/DottyUnpickler.scala
+++ b/compiler/src/dotty/tools/dotc/core/tasty/DottyUnpickler.scala
@@ -46,6 +46,9 @@ class DottyUnpickler(bytes: Array[Byte]) extends ClassfileParser.Embedded with t
   def enter(roots: Set[SymDenotation])(implicit ctx: Context): Unit =
     treeUnpickler.enterTopLevel(roots)
 
+  def unpickleExpr()(implicit ctx: Context): Tree =
+    treeUnpickler.unpickleExpr()
+
   protected def treeSectionUnpickler(posUnpicklerOpt: Option[PositionUnpickler]): TreeSectionUnpickler = {
     new TreeSectionUnpickler(posUnpicklerOpt)
   }
diff --git a/compiler/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala b/compiler/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala
index 2d7ae573d48f..620dd44f84e9 100644
--- a/compiler/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala
+++ b/compiler/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala
@@ -73,11 +73,18 @@ class TreeUnpickler(reader: TastyReader,
    */
   def enterTopLevel(roots: Set[SymDenotation])(implicit ctx: Context): Unit = {
     this.roots = roots
-    var rdr = new TreeReader(reader).fork
+    val rdr = new TreeReader(reader).fork
     ownerTree = new OwnerTree(NoAddr, 0, rdr.fork, reader.endAddr)
     rdr.indexStats(reader.endAddr)
   }
 
+  def unpickleExpr()(implicit ctx: Context): Tree = {
+    this.roots = Set(ctx.owner)
+    val rdr = new TreeReader(reader).fork
+    ownerTree = new OwnerTree(NoAddr, 0, rdr.fork, reader.endAddr)
+    rdr.readTerm()
+  }
+
   /** The unpickled trees */
   def unpickle()(implicit ctx: Context): List[Tree] = {
     assert(roots != null, "unpickle without previous enterTopLevel")
diff --git a/tests/run-with-compiler/quote-owners-2.check b/tests/run-with-compiler/quote-owners-2.check
new file mode 100644
index 000000000000..fee34077c6f9
--- /dev/null
+++ b/tests/run-with-compiler/quote-owners-2.check
@@ -0,0 +1,14 @@
+3
+{
+  def ff: Int = 
+    {
+      val a: List[Int] = 
+        {
+          type T = List[Int]
+          val b: T = Nil.::[Int](3)
+          b: List[Int]
+        }
+      a.head: Int
+    }
+  ff: Int
+}
diff --git a/tests/run-with-compiler/quote-owners-2.scala b/tests/run-with-compiler/quote-owners-2.scala
new file mode 100644
index 000000000000..7e2d11e9b374
--- /dev/null
+++ b/tests/run-with-compiler/quote-owners-2.scala
@@ -0,0 +1,25 @@
+
+import quoted._
+import dotty.tools.dotc.quoted.Toolbox._
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    val q = f(g(Type.IntTag))
+    println(q.run)
+    println(q.show)
+  }
+
+  def f(t: Type[List[Int]]): Expr[Int] = '{
+    def ff: Int = {
+      val a: ~t = {
+        type T = ~t
+        val b: T = 3 :: Nil
+        b
+      }
+      a.head
+    }
+    ff
+  }
+
+  def g[T](a: Type[T]): Type[List[T]] = '[List[~a]]
+}
diff --git a/tests/run-with-compiler/quote-owners.check b/tests/run-with-compiler/quote-owners.check
new file mode 100644
index 000000000000..8b1f473d369a
--- /dev/null
+++ b/tests/run-with-compiler/quote-owners.check
@@ -0,0 +1,9 @@
+9
+{
+  def ff: Int = 
+    {
+      val a: Int = 9
+      a.+(0)
+    }
+  ff: Int
+}
diff --git a/tests/run-with-compiler/quote-owners.scala b/tests/run-with-compiler/quote-owners.scala
new file mode 100644
index 000000000000..1ccadf592d0a
--- /dev/null
+++ b/tests/run-with-compiler/quote-owners.scala
@@ -0,0 +1,22 @@
+import quoted._
+import dotty.tools.dotc.quoted.Toolbox._
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    val q = f
+    println(q.run)
+    println(q.show)
+  }
+
+  def f: Expr[Int] = '{
+    def ff: Int = {
+      ~g
+    }
+    ff
+  }
+
+  def g: Expr[Int] = '{
+    val a = 9
+    a + 0
+  }
+}
diff --git a/tests/run-with-compiler/quote-run-large.scala b/tests/run-with-compiler/quote-run-large.scala
index 43f02704700d..46e90e29a3b1 100644
--- a/tests/run-with-compiler/quote-run-large.scala
+++ b/tests/run-with-compiler/quote-run-large.scala
@@ -51,6 +51,11 @@ object Test {
         def foo42: Int = x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x
         def foo43: Int = x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x
         def foo44: Int = x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x
+        def foo45: Int = x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x
+        def foo46: Int = x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x
+        def foo47: Int = x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x
+        def foo48: Int = x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x
+        def foo49: Int = x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x + x
       }
 
       new Foo(5)