Merge pull request #2033 from adriaanm/patmat-opt

pattern matching efficiency: addresses SI-6686 and SI-6941, affects SI-5739

16 files changed, 142 insertions, 0 deletions

diff --git a/test/files/jvm/patmat_opt_ignore_underscore.check b/test/files/jvm/patmat_opt_ignore_underscore.check
new file mode 100644
index 0000000000..43f53aba12
--- /dev/null
+++ b/test/files/jvm/patmat_opt_ignore_underscore.check
@@ -0,0 +1 @@
+bytecode identical
diff --git a/test/files/jvm/patmat_opt_ignore_underscore.flags b/test/files/jvm/patmat_opt_ignore_underscore.flags
new file mode 100644
index 0000000000..1182725e86
--- /dev/null
+++ b/test/files/jvm/patmat_opt_ignore_underscore.flags
@@ -0,0 +1 @@
+-optimize
\ No newline at end of file
diff --git a/test/files/jvm/patmat_opt_ignore_underscore/Analyzed_1.scala b/test/files/jvm/patmat_opt_ignore_underscore/Analyzed_1.scala
new file mode 100644
index 0000000000..fa3639380d
--- /dev/null
+++ b/test/files/jvm/patmat_opt_ignore_underscore/Analyzed_1.scala
@@ -0,0 +1,29 @@
+// this class's bytecode, compiled under -optimize is analyzed by the test
+// method a's bytecode should be identical to method b's bytecode
+// this is not the best test for shielding against regressing on this particular issue,
+// but it sets the stage for checking the bytecode emitted by the pattern matcher and
+// comparing it to manually tuned code using if/then/else etc.
+class SameBytecode {
+  case class Foo(x: Any, y: String)
+
+  def a = 
+    Foo(1, "a") match {
+      case Foo(_: String, y) => y
+    }
+
+  // this method's body holds the tree that should be generated by the pattern matcher for method a (-Xprint:patmat)
+  // the test checks that bytecode for a and b is identical (modulo line numbers)
+  // we can't diff trees as they are quite different (patmat uses jumps to labels that cannot be expressed in source, for example)
+  // note that the actual tree is quite bad: we do an unnecessary null check, isInstanceOf and local val (x3)
+  // some of these will be fixed soon (the initial null check is for the scrutinee, which is harder to fix in patmat)
+  def b: String = {
+    val x1 = Foo(1, "a")
+    if (x1.ne(null)) {
+      if (x1.x.isInstanceOf[String]) {
+        return x1.y
+      }
+    }
+
+    throw new MatchError(x1)
+  }
+}
\ No newline at end of file
diff --git a/test/files/jvm/patmat_opt_ignore_underscore/test.scala b/test/files/jvm/patmat_opt_ignore_underscore/test.scala
new file mode 100644
index 0000000000..6179101a7e
--- /dev/null
+++ b/test/files/jvm/patmat_opt_ignore_underscore/test.scala
@@ -0,0 +1,15 @@
+import scala.tools.partest.BytecodeTest
+
+import scala.tools.nsc.util.JavaClassPath
+import java.io.InputStream
+import scala.tools.asm
+import asm.ClassReader
+import asm.tree.{ClassNode, InsnList}
+import scala.collection.JavaConverters._
+
+object Test extends BytecodeTest {
+  def show: Unit = {
+    val classNode = loadClassNode("SameBytecode")
+    sameBytecode(getMethod(classNode, "a"), getMethod(classNode, "b"))
+  }
+}
diff --git a/test/files/jvm/patmat_opt_no_nullcheck.check b/test/files/jvm/patmat_opt_no_nullcheck.check
new file mode 100644
index 0000000000..43f53aba12
--- /dev/null
+++ b/test/files/jvm/patmat_opt_no_nullcheck.check
@@ -0,0 +1 @@
+bytecode identical
diff --git a/test/files/jvm/patmat_opt_no_nullcheck.flags b/test/files/jvm/patmat_opt_no_nullcheck.flags
new file mode 100644
index 0000000000..1182725e86
--- /dev/null
+++ b/test/files/jvm/patmat_opt_no_nullcheck.flags
@@ -0,0 +1 @@
+-optimize
\ No newline at end of file
diff --git a/test/files/jvm/patmat_opt_no_nullcheck/Analyzed_1.scala b/test/files/jvm/patmat_opt_no_nullcheck/Analyzed_1.scala
new file mode 100644
index 0000000000..3a594c401e
--- /dev/null
+++ b/test/files/jvm/patmat_opt_no_nullcheck/Analyzed_1.scala
@@ -0,0 +1,24 @@
+// this class's bytecode, compiled under -optimize is analyzed by the test
+// method a's bytecode should be identical to method b's bytecode
+case class Foo(x: Any)
+
+class SameBytecode {
+  def a = 
+    (Foo(1): Any) match {
+      case Foo(_: String) =>
+    }
+
+  // there's no null check
+  def b: Unit = {
+    val x1: Any = Foo(1)
+    if (x1.isInstanceOf[Foo]) {
+      val x3 = x1.asInstanceOf[Foo]
+      if (x3.x.isInstanceOf[String]) {
+        val x = ()
+        return
+      }
+    }
+
+    throw new MatchError(x1)
+  }
+}
\ No newline at end of file
diff --git a/test/files/jvm/patmat_opt_no_nullcheck/test.scala b/test/files/jvm/patmat_opt_no_nullcheck/test.scala
new file mode 100644
index 0000000000..2927e763d5
--- /dev/null
+++ b/test/files/jvm/patmat_opt_no_nullcheck/test.scala
@@ -0,0 +1,8 @@
+import scala.tools.partest.BytecodeTest
+
+object Test extends BytecodeTest {
+  def show: Unit = {
+    val classNode = loadClassNode("SameBytecode")
+    sameBytecode(getMethod(classNode, "a"), getMethod(classNode, "b"))
+  }
+}
diff --git a/test/files/jvm/patmat_opt_primitive_typetest.check b/test/files/jvm/patmat_opt_primitive_typetest.check
new file mode 100644
index 0000000000..43f53aba12
--- /dev/null
+++ b/test/files/jvm/patmat_opt_primitive_typetest.check
@@ -0,0 +1 @@
+bytecode identical
diff --git a/test/files/jvm/patmat_opt_primitive_typetest.flags b/test/files/jvm/patmat_opt_primitive_typetest.flags
new file mode 100644
index 0000000000..49d036a887
--- /dev/null
+++ b/test/files/jvm/patmat_opt_primitive_typetest.flags
@@ -0,0 +1 @@
+-optimize
diff --git a/test/files/jvm/patmat_opt_primitive_typetest/Analyzed_1.scala b/test/files/jvm/patmat_opt_primitive_typetest/Analyzed_1.scala
new file mode 100644
index 0000000000..e5db6c4dd0
--- /dev/null
+++ b/test/files/jvm/patmat_opt_primitive_typetest/Analyzed_1.scala
@@ -0,0 +1,24 @@
+// this class's bytecode, compiled under -optimize is analyzed by the test
+// method a's bytecode should be identical to method b's bytecode
+class SameBytecode {
+  case class Foo(x: Int, y: String)
+
+  def a = 
+    Foo(1, "a") match {
+      case Foo(_: Int, y) => y
+    }
+
+  // this method's body holds the tree that should be generated by the pattern matcher for method a (-Xprint:patmat)
+  // the test checks that bytecode for a and b is identical (modulo line numbers)
+  // we can't diff trees as they are quite different (patmat uses jumps to labels that cannot be expressed in source, for example)
+  // note that the actual tree is quite bad: we do an unnecessary null check, and local val (x3)
+  // some of these will be fixed soon (the initial null check is for the scrutinee, which is harder to fix in patmat)
+  def b: String = {
+    val x1 = Foo(1, "a")
+    if (x1.ne(null)) {
+      return x1.y
+    }
+
+    throw new MatchError(x1)
+  }
+}
\ No newline at end of file
diff --git a/test/files/jvm/patmat_opt_primitive_typetest/test.scala b/test/files/jvm/patmat_opt_primitive_typetest/test.scala
new file mode 100644
index 0000000000..2927e763d5
--- /dev/null
+++ b/test/files/jvm/patmat_opt_primitive_typetest/test.scala
@@ -0,0 +1,8 @@
+import scala.tools.partest.BytecodeTest
+
+object Test extends BytecodeTest {
+  def show: Unit = {
+    val classNode = loadClassNode("SameBytecode")
+    sameBytecode(getMethod(classNode, "a"), getMethod(classNode, "b"))
+  }
+}
diff --git a/test/files/jvm/t6941.check b/test/files/jvm/t6941.check
new file mode 100644
index 0000000000..43f53aba12
--- /dev/null
+++ b/test/files/jvm/t6941.check
@@ -0,0 +1 @@
+bytecode identical
diff --git a/test/files/jvm/t6941.flags b/test/files/jvm/t6941.flags
new file mode 100644
index 0000000000..49d036a887
--- /dev/null
+++ b/test/files/jvm/t6941.flags
@@ -0,0 +1 @@
+-optimize
diff --git a/test/files/jvm/t6941/Analyzed_1.scala b/test/files/jvm/t6941/Analyzed_1.scala
new file mode 100644
index 0000000000..549abd5e64
--- /dev/null
+++ b/test/files/jvm/t6941/Analyzed_1.scala
@@ -0,0 +1,11 @@
+// this class's bytecode, compiled under -optimize is analyzed by the test
+// method a's bytecode should be identical to method b's bytecode
+class SameBytecode {
+  def a(xs: List[Int]) = xs match {
+    case x :: _ => x
+  }
+
+  def b(xs: List[Int]) = xs match {
+    case xs: ::[Int] => xs.hd$1
+  }
+}
\ No newline at end of file
diff --git a/test/files/jvm/t6941/test.scala b/test/files/jvm/t6941/test.scala
new file mode 100644
index 0000000000..248617f71f
--- /dev/null
+++ b/test/files/jvm/t6941/test.scala
@@ -0,0 +1,15 @@
+import scala.tools.partest.BytecodeTest
+
+import scala.tools.nsc.util.JavaClassPath
+import java.io.InputStream
+import scala.tools.asm
+import asm.ClassReader
+import asm.tree.{ClassNode, InsnList}
+import scala.collection.JavaConverters._
+
+object Test extends BytecodeTest {
+  def show: Unit = {
+    val classNode = loadClassNode("SameBytecode")
+    similarBytecode(getMethod(classNode, "a"), getMethod(classNode, "b"), equalsModuloVar)
+  }
+}