[rvm-commits] code: Big fixes in annotation processing for empty arrays ({}).

[<jik...@li...>]

details:   http://hg.code.sourceforge.net/p/jikesrvm/codecode/rev/f468849b03fa
changeset: 10552:f468849b03fa
user:      Dave Grove <gr...@us...>
date:      Fri Oct 12 20:21:01 2012 -0400
description:
Big fixes in annotation processing for empty arrays ({}).
The existing code was buggy in two ways (a) if the type was known, it
was creating a T[][] instead of a T[] and (b) if the type was unknown
it was blindly creating an Object[], which results in a runtime checkcast
failure when the annotation tried to read the value.

Thanks to Matt Brown and Jens Palsberg at UCLA for the test case.


diffstat:

 rvm/src/org/jikesrvm/classloader/RVMAnnotation.java |  17 +++++++++++++----
 1 files changed, 13 insertions(+), 4 deletions(-)

diffs (34 lines):

diff --git a/rvm/src/org/jikesrvm/classloader/RVMAnnotation.java b/rvm/src/org/jikesrvm/classloader/RVMAnnotation.java
--- a/rvm/src/org/jikesrvm/classloader/RVMAnnotation.java
+++ b/rvm/src/org/jikesrvm/classloader/RVMAnnotation.java
@@ -232,7 +232,7 @@
         int numValues = input.readUnsignedShort();
         if (numValues == 0) {
           if (type != null) {
-            value = Array.newInstance(type.resolve().getClassForType(), 0);
+            value = Array.newInstance(type.getArrayElementType().resolve().getClassForType(), 0);
           } else {
             value = new Object[0];
           }
@@ -651,9 +651,18 @@
         value = RVMAnnotation.readValue(meth.getReturnType(), constantPool, input, classLoader);
       } else {
         value = RVMAnnotation.readValue(null, constantPool, input, classLoader);
-        meth = MemberReference.findOrCreate(type, name,
-            Atom.findOrCreateAsciiAtom("()"+TypeReference.findOrCreate(value.getClass()).getName())
-        ).asMethodReference();
+        if (value instanceof Object[] && ((Object[])value).length == 0) {
+            // We blindly guessed Object[] in readValue.
+            // No choice but to force type to be resolved so we actually
+            // create an empty array of the appropriate type.
+            meth = type.resolve().asClass().findDeclaredMethod(name).getMemberRef().asMethodReference();
+            value = Array.newInstance(meth.getReturnType().getArrayElementType().resolve().getClassForType(), 0);
+        } else {
+            // Reading the value lets us make a MemberReference that is likely to be correct.
+            meth = MemberReference.findOrCreate(type, name,
+                    Atom.findOrCreateAsciiAtom("()"+TypeReference.findOrCreate(value.getClass()).getName())
+            ).asMethodReference();
+        }
       }
       return new AnnotationMember(meth, value);
     }