Equivalent .class fields should share the same symbol

[B. Blaser]

Hi,

As mentioned in [1], equivalent .class fields should share the same symbol.
The fix below caches .class symbols per unique type.

All javac tests are passing successfully.

Does this look reasonable?

Thanks,
Bernard

[1] http://mail.openjdk.java.net/pipermail/amber-dev/2018-April/002897.html

diff -r 8c85a1855e10
src/jdk.compiler/share/classes/com/sun/tools/javac/code/Symtab.java
--- a/src/jdk.compiler/share/classes/com/sun/tools/javac/code/Symtab.java
Fri Apr 13 11:14:49 2018 -0700
+++ b/src/jdk.compiler/share/classes/com/sun/tools/javac/code/Symtab.java
Sun Apr 15 13:42:07 2018 +0200
@@ -247,6 +247,8 @@
      */
     private final Map<Name, ModuleSymbol> modules = new LinkedHashMap<>();

+    public final Map<Types.UniqueType, VarSymbol> _class = new HashMap<>();
+
     public void initType(Type type, ClassSymbol c) {
         type.tsym = c;
         typeOfTag[type.getTag().ordinal()] = type;
diff -r 8c85a1855e10
src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Attr.java
--- a/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Attr.java
Fri Apr 13 11:14:49 2018 -0700
+++ b/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Attr.java
Sun Apr 15 13:42:07 2018 +0200
@@ -3734,8 +3734,11 @@
                     Type t = syms.classType;
                     List<Type> typeargs = List.of(types.erasure(site));
                     t = new ClassType(t.getEnclosingType(), typeargs, t.tsym);
-                    return new VarSymbol(
+                    VarSymbol _class = new VarSymbol(
                         STATIC | PUBLIC | FINAL, names._class, t, site.tsym);
+                    VarSymbol existing = syms._class.putIfAbsent(
+                        new Types.UniqueType(site, types), _class);
+                    return existing != null ? existing : _class;
                 } else {
                     // We are seeing a plain identifier as selector.
                     Symbol sym = rs.findIdentInType(env, site, name,
resultInfo.pkind);
@@ -3776,8 +3779,11 @@
                     Type t = syms.classType;
                     Type arg = types.boxedClass(site).type;
                     t = new ClassType(t.getEnclosingType(),
List.of(arg), t.tsym);
-                    return new VarSymbol(
+                    VarSymbol _class = new VarSymbol(
                         STATIC | PUBLIC | FINAL, names._class, t, site.tsym);
+                    VarSymbol existing = syms._class.putIfAbsent(
+                        new Types.UniqueType(site, types), _class);
+                    return existing != null ? existing : _class;
                 } else {
                     log.error(pos, Errors.CantDeref(site));
                     return syms.errSymbol;
diff -r 8c85a1855e10
test/langtools/tools/javac/lambda/deduplication/Deduplication.java
--- a/test/langtools/tools/javac/lambda/deduplication/Deduplication.java
Fri Apr 13 11:14:49 2018 -0700
+++ b/test/langtools/tools/javac/lambda/deduplication/Deduplication.java
Sun Apr 15 13:42:07 2018 +0200
@@ -38,6 +38,21 @@
                 (Runnable) () -> { ( (Runnable) () -> {} ).run(); }
         );

+        group(
+                (Runnable) () -> { Deduplication.class.toString(); },
+                (Runnable) () -> { Deduplication.class.toString(); }
+        );
+
+        group(
+                (Runnable) () -> { Integer[].class.toString(); },
+                (Runnable) () -> { Integer[].class.toString(); }
+        );
+
+        group(
+                (Runnable) () -> { char.class.toString(); },
+                (Runnable) () -> { char.class.toString(); }
+        );
+
         group((Function<String, Integer>) x -> x.hashCode());
         group((Function<Object, Integer>) x -> x.hashCode());