classfile reader: allow JDK 9+ constant types in constant pool

forward-port of scala/scala#10675 and scala/scala#8595
references scala/bug#12396 and scala/bug#11635
fixes #19527 ("bad constant pool tag 17")
also fixes unreported potential "bad constant pool tag 19" and
"bad constant pool tag 20" errors

Author: SethTisue

compiler/src/dotty/tools/dotc/core/classfile/ClassfileConstants.scala

@@ -73,7 +73,10 @@ object ClassfileConstants {
 
   inline val CONSTANT_METHODHANDLE  = 15
   inline val CONSTANT_METHODTYPE    = 16
+  inline val CONSTANT_DYNAMIC       = 17
   inline val CONSTANT_INVOKEDYNAMIC = 18
+  inline val CONSTANT_MODULE        = 19
+  inline val CONSTANT_PACKAGE       = 20
 
   // tags describing the type of a literal in attribute values
   inline val BYTE_TAG   = 'B'

compiler/src/dotty/tools/dotc/core/classfile/ClassfileParser.scala

@@ -1224,13 +1224,14 @@ class ClassfileParser(
         (in.nextByte.toInt: @switch) match {
           case CONSTANT_UTF8 | CONSTANT_UNICODE =>
             in.skip(in.nextChar)
-          case CONSTANT_CLASS | CONSTANT_STRING | CONSTANT_METHODTYPE =>
+          case CONSTANT_CLASS | CONSTANT_STRING | CONSTANT_METHODTYPE
+             | CONSTANT_MODULE | CONSTANT_PACKAGE =>
             in.skip(2)
           case CONSTANT_METHODHANDLE =>
             in.skip(3)
           case CONSTANT_FIELDREF | CONSTANT_METHODREF | CONSTANT_INTFMETHODREF
              | CONSTANT_NAMEANDTYPE | CONSTANT_INTEGER | CONSTANT_FLOAT
-             | CONSTANT_INVOKEDYNAMIC =>
+             | CONSTANT_INVOKEDYNAMIC | CONSTANT_DYNAMIC =>
             in.skip(4)
           case CONSTANT_LONG | CONSTANT_DOUBLE =>
             in.skip(8)

compiler/test/dotty/tools/backend/jvm/ClassfileParserTest.scala

@@ -36,6 +36,7 @@ class ClassfileParserTest {
       // in ClassfileConstants! that would defeat the purpose of the test
       "CONSTANT_CLASS",
       "CONSTANT_DOUBLE",
+      "CONSTANT_DYNAMIC",
       "CONSTANT_FIELDREF",
       "CONSTANT_FLOAT",
       "CONSTANT_INTEGER",
@@ -45,7 +46,9 @@ class ClassfileParserTest {
       "CONSTANT_METHODHANDLE",
       "CONSTANT_METHODREF",
       "CONSTANT_METHODTYPE",
+      "CONSTANT_MODULE",
       "CONSTANT_NAMEANDTYPE",
+      "CONSTANT_PACKAGE",
       "CONSTANT_STRING",
       "CONSTANT_UNICODE",
       "CONSTANT_UTF8",

tests/pos/t12396/A_1.java

@@ -0,0 +1,17 @@
+// test: -jvm 21+
+
+public class A_1 {
+  public int f(Object s) {
+    switch(s) {
+      case Res.R -> {
+        return 1;
+      }
+      default -> {
+        return 3;
+      }
+    }
+  }
+  static enum Res {
+    R
+  }
+}

tests/pos/t12396/B_2.scala

@@ -0,0 +1,5 @@
+// test: -jvm 21+
+
+class B {
+  def bar = (new A_1).f(null)
+}