Hi John!
I'm currently porting the interpreter to x86_64 and there is a problem
that took me almost two days to find: it's the MethodHandle.vmentry
field-type change.
For whatever reason on 64-bit it calculates the offset to 24, which
actually should be 16, and that results to this:
sun.dyn.DirectMethodHandle
- klass: 'sun/dyn/DirectMethodHandle'
- ---- fields (total size 6 words):
- private 'vmentry' 'J' @24 4329412000 (20d95a0 1)
- protected 'vmtarget' 'Ljava/lang/Object;' @24 ### BAD OOP
0x1020d95a0 ### (20d95a0 1)
- private 'type' 'Ljava/dyn/MethodType;' @32 a 'java/dyn/MethodType' =
(II)I (5040e38 1)
- private final 'vmindex' 'I' @40 -2 (fffffffe)
Nice, isn't it? :-)
So, there is a problem somewhere in
ClassFileParser::java_dyn_MethodHandle_fix_pre and the attached patch
fix it. But I'm very sure this is not correct as the field should
really be a double field and not a word field. What is the "correct"
fix for this problem?
-- Christian
diff --git a/src/share/vm/classfile/classFileParser.cpp
b/src/share/vm/classfile/classFileParser.cpp
--- a/src/share/vm/classfile/classFileParser.cpp
+++ b/src/share/vm/classfile/classFileParser.cpp
@@ -2514,23 +2514,23 @@
fac_ptr->nonstatic_byte_count -= 1;
(*fields_ptr)->ushort_at_put(i +
instanceKlass::signature_index_offset,
word_sig_index);
- if (wordSize == jintSize) {
+// if (wordSize == jintSize) {
fac_ptr->nonstatic_word_count += 1;
- } else {
- fac_ptr->nonstatic_double_count += 1;
- }
-
- FieldAllocationType atype = (FieldAllocationType)
(*fields_ptr)->ushort_at(i+4);
+// } else {
+// fac_ptr->nonstatic_double_count += 1;
+// }
+
+ FieldAllocationType atype = (FieldAllocationType)
(*fields_ptr)->ushort_at(i + instanceKlass::low_offset);
assert(atype == NONSTATIC_BYTE, "");
FieldAllocationType new_atype = NONSTATIC_WORD;
- if (wordSize > jintSize) {
- if (Universe::field_type_should_be_aligned(T_LONG)) {
- atype = NONSTATIC_ALIGNED_DOUBLE;
- } else {
- atype = NONSTATIC_DOUBLE;
- }
- }
- (*fields_ptr)->ushort_at_put(i+4, new_atype);
+// if (wordSize > jintSize) {
+// if (Universe::field_type_should_be_aligned(T_LONG)) {
+// atype = NONSTATIC_ALIGNED_DOUBLE;
+// } else {
+// atype = NONSTATIC_DOUBLE;
+// }
+// }
+ (*fields_ptr)->ushort_at_put(i + instanceKlass::low_offset,
new_atype);
found_vmentry = true;
break;
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