From c56057e40938c587a74984651a510e320a8cb4fd Mon Sep 17 00:00:00 2001
From: Mathieu Chartier <mathieuc@google.com>
Date: Sun, 4 May 2014 13:18:58 -0700
Subject: Add lockless SynchronizedGet for indirect reference table.

Used for decoding global references without holding locks.

Results on JniCallback:
Before: 615ms (3 samples).
After: 585ms (3 samples).

Change-Id: Ifcac8d0359cf658d87f695c6eb869d148af002e5
---
 runtime/indirect_reference_table-inl.h | 87 ++++++++++++++++++++++++++++++++++
 1 file changed, 87 insertions(+)
 create mode 100644 runtime/indirect_reference_table-inl.h

(limited to 'runtime/indirect_reference_table-inl.h')

diff --git a/runtime/indirect_reference_table-inl.h b/runtime/indirect_reference_table-inl.h
new file mode 100644
index 0000000000..1a28347bcb
--- /dev/null
+++ b/runtime/indirect_reference_table-inl.h
@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ART_RUNTIME_INDIRECT_REFERENCE_TABLE_INL_H_
+#define ART_RUNTIME_INDIRECT_REFERENCE_TABLE_INL_H_
+
+#include "indirect_reference_table.h"
+
+#include "verify_object-inl.h"
+
+namespace art {
+namespace mirror {
+class Object;
+}  // namespace mirror
+
+// Verifies that the indirect table lookup is valid.
+// Returns "false" if something looks bad.
+inline bool IndirectReferenceTable::GetChecked(IndirectRef iref) const {
+  if (UNLIKELY(iref == nullptr)) {
+    LOG(WARNING) << "Attempt to look up NULL " << kind_;
+    return false;
+  }
+  if (UNLIKELY(GetIndirectRefKind(iref) == kSirtOrInvalid)) {
+    LOG(ERROR) << "JNI ERROR (app bug): invalid " << kind_ << " " << iref;
+    AbortIfNoCheckJNI();
+    return false;
+  }
+  const int topIndex = segment_state_.parts.topIndex;
+  int idx = ExtractIndex(iref);
+  if (UNLIKELY(idx >= topIndex)) {
+    LOG(ERROR) << "JNI ERROR (app bug): accessed stale " << kind_ << " "
+               << iref << " (index " << idx << " in a table of size " << topIndex << ")";
+    AbortIfNoCheckJNI();
+    return false;
+  }
+  if (UNLIKELY(table_[idx] == nullptr)) {
+    LOG(ERROR) << "JNI ERROR (app bug): accessed deleted " << kind_ << " " << iref;
+    AbortIfNoCheckJNI();
+    return false;
+  }
+  if (UNLIKELY(!CheckEntry("use", iref, idx))) {
+    return false;
+  }
+  return true;
+}
+
+// Make sure that the entry at "idx" is correctly paired with "iref".
+inline bool IndirectReferenceTable::CheckEntry(const char* what, IndirectRef iref, int idx) const {
+  const mirror::Object* obj = table_[idx];
+  IndirectRef checkRef = ToIndirectRef(obj, idx);
+  if (UNLIKELY(checkRef != iref)) {
+    LOG(ERROR) << "JNI ERROR (app bug): attempt to " << what
+               << " stale " << kind_ << " " << iref
+               << " (should be " << checkRef << ")";
+    AbortIfNoCheckJNI();
+    return false;
+  }
+  return true;
+}
+
+inline mirror::Object* IndirectReferenceTable::Get(IndirectRef iref) const {
+  if (!GetChecked(iref)) {
+    return kInvalidIndirectRefObject;
+  }
+  mirror::Object* obj = table_[ExtractIndex(iref)];
+  if (LIKELY(obj != kClearedJniWeakGlobal)) {
+    VerifyObject(obj);
+  }
+  return obj;
+}
+
+}  // namespace art
+
+#endif  // ART_RUNTIME_INDIRECT_REFERENCE_TABLE_INL_H_
-- 
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