Remove abuse of mirror::Object* to reference special values.

Remove kInvalidIndirectRefObject, kClearedJniWeakGlobal and
ObjectRegistry::kInvalidObject. Handle error conditions by passing in or
returning an error value.
GetObjectRefType is simplified to be faster and not return invalid references
that are not expected according to the spec. Adjust check JNI and
jni_internal_test appropriately.
Fix cases in the debugger/JDWP of out arguments being passed by reference.
Bug: 17376993

Change-Id: I3ce8a28c01827e163f4dc288449959464da788b1

1 files changed, 13 insertions, 7 deletions

diff --git a/runtime/indirect_reference_table-inl.h b/runtime/indirect_reference_table-inl.h
index 00f7b06..9bf3ea2 100644
--- a/runtime/indirect_reference_table-inl.h
+++ b/runtime/indirect_reference_table-inl.h
@@ -19,6 +19,7 @@
 
 #include "indirect_reference_table.h"
 
+#include "runtime-inl.h"
 #include "verify_object-inl.h"
 
 namespace art {
@@ -26,6 +27,15 @@ namespace mirror {
 class Object;
 }  // namespace mirror
 
+inline void IrtIterator::SkipNullsAndTombstones() {
+  // We skip NULLs and tombstones. Clients don't want to see implementation details.
+  while (i_ < capacity_ &&
+         (table_[i_].IsNull() ||
+          Runtime::Current()->IsClearedJniWeakGlobal(table_[i_].Read<kWithoutReadBarrier>()))) {
+    ++i_;
+  }
+}
+
 // Verifies that the indirect table lookup is valid.
 // Returns "false" if something looks bad.
 inline bool IndirectReferenceTable::GetChecked(IndirectRef iref) const {
@@ -73,15 +83,11 @@ inline bool IndirectReferenceTable::CheckEntry(const char* what, IndirectRef ire
 template<ReadBarrierOption kReadBarrierOption>
 inline mirror::Object* IndirectReferenceTable::Get(IndirectRef iref) const {
   if (!GetChecked(iref)) {
-    return kInvalidIndirectRefObject;
+    return nullptr;
   }
   uint32_t idx = ExtractIndex(iref);
-  mirror::Object* obj = table_[idx].Read<kWithoutReadBarrier>();
-  if (LIKELY(obj != kClearedJniWeakGlobal)) {
-    // The read barrier or VerifyObject won't handle kClearedJniWeakGlobal.
-    obj = table_[idx].Read<kReadBarrierOption>();
-    VerifyObject(obj);
-  }
+  mirror::Object* obj = table_[idx].Read<kReadBarrierOption>();
+  VerifyObject(obj);
   return obj;
 }