1 files changed, 77 insertions, 0 deletions
diff --git a/runtime/imtable.h b/runtime/imtable.h
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--- /dev/null
+++ b/runtime/imtable.h
@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2016 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_IMTABLE_H_
+#define ART_RUNTIME_IMTABLE_H_
+
+#ifndef IMT_SIZE
+#error IMT_SIZE not defined
+#endif
+
+namespace art {
+
+class ArtMethod;
+
+class ImTable {
+ public:
+  // Interface method table size. Increasing this value reduces the chance of two interface methods
+  // colliding in the interface method table but increases the size of classes that implement
+  // (non-marker) interfaces.
+  static constexpr size_t kSize = IMT_SIZE;
+
+  ArtMethod* Get(size_t index, size_t pointer_size) {
+    DCHECK_LT(index, kSize);
+    uint8_t* ptr = reinterpret_cast<uint8_t*>(this) + OffsetOfElement(index, pointer_size);
+    if (pointer_size == 4) {
+      uint32_t value = *reinterpret_cast<uint32_t*>(ptr);
+      return reinterpret_cast<ArtMethod*>(value);
+    } else {
+      uint64_t value = *reinterpret_cast<uint64_t*>(ptr);
+      return reinterpret_cast<ArtMethod*>(value);
+    }
+  }
+
+  void Set(size_t index, ArtMethod* method, size_t pointer_size) {
+    DCHECK_LT(index, kSize);
+    uint8_t* ptr = reinterpret_cast<uint8_t*>(this) + OffsetOfElement(index, pointer_size);
+    if (pointer_size == 4) {
+      uintptr_t value = reinterpret_cast<uintptr_t>(method);
+      DCHECK_EQ(static_cast<uint32_t>(value), value);  // Check that we dont lose any non 0 bits.
+      *reinterpret_cast<uint32_t*>(ptr) = static_cast<uint32_t>(value);
+    } else {
+      *reinterpret_cast<uint64_t*>(ptr) = reinterpret_cast<uint64_t>(method);
+    }
+  }
+
+  static size_t OffsetOfElement(size_t index, size_t pointer_size) {
+    return index * pointer_size;
+  }
+
+  void Populate(ArtMethod** data, size_t pointer_size) {
+    for (size_t i = 0; i < kSize; ++i) {
+      Set(i, data[i], pointer_size);
+    }
+  }
+
+  constexpr static size_t SizeInBytes(size_t pointer_size) {
+    return kSize * pointer_size;
+  }
+};
+
+}  // namespace art
+
+#endif  // ART_RUNTIME_IMTABLE_H_
+