lambda: Add support for invoke-interface for boxed innate lambdas

Lambda closures created with the 'create-lambda' instruction
(termed "innate lambdas") can be turned into an object with 'box-lambda'.

This CL enables support for those kinds of lambdas to work with
'invoke-interface' by generating a proxy class for the lambda.

Note: MIPS32/64 support not included.

Bug: 24618608
Bug: 25107649
Change-Id: Ic8f1bb66ebeaed4097e758a50becf1cff6ccaefb
diff --git a/runtime/mirror/lambda_proxy.h b/runtime/mirror/lambda_proxy.h
new file mode 100644
index 0000000..cff3a12
--- /dev/null
+++ b/runtime/mirror/lambda_proxy.h
@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2015 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_MIRROR_LAMBDA_PROXY_H_
+#define ART_RUNTIME_MIRROR_LAMBDA_PROXY_H_
+
+#include "lambda/closure.h"
+#include "object.h"
+
+namespace art {
+
+struct LambdaProxyOffsets;
+
+namespace mirror {
+
+// C++ mirror of a lambda proxy. Does not yet have a Java-equivalent source file.
+class MANAGED LambdaProxy FINAL : public Object {
+ public:
+  // Note that the runtime subclasses generate the following static fields:
+
+  // private static java.lang.Class[] interfaces;  // Declared interfaces for the lambda interface.
+  static constexpr size_t kStaticFieldIndexInterfaces = 0;
+  // private static java.lang.Class[][] throws;    // Maps vtable id to list of classes.
+  static constexpr size_t kStaticFieldIndexThrows = 1;
+  static constexpr size_t kStaticFieldCount = 2;   // Number of fields total.
+
+  // The offset from the start of 'LambdaProxy' object, to the closure_ field, in bytes.
+  // -- This is exposed publically in order to avoid exposing 'closure_' publically.
+  // -- Only meant to be used in stubs and other compiled code, not in runtime.
+  static inline MemberOffset GetInstanceFieldOffsetClosure() {
+    return OFFSET_OF_OBJECT_MEMBER(LambdaProxy, closure_);
+  }
+
+  // Direct methods available on the class:
+  static constexpr size_t kDirectMethodIndexConstructor = 0;  // <init>()V
+  static constexpr size_t kDirectMethodCount = 1;             // Only the constructor.
+
+  // Accessors to the fields:
+
+  // Get the native closure pointer. Usually non-null outside of lambda proxy contexts.
+  lambda::Closure* GetClosure() SHARED_REQUIRES(Locks::mutator_lock_) {
+    return reinterpret_cast<lambda::Closure*>(
+        GetField64(GetInstanceFieldOffsetClosure()));
+  }
+
+  // Set the native closure pointer. Usually should be non-null outside of lambda proxy contexts.
+  void SetClosure(lambda::Closure* closure) SHARED_REQUIRES(Locks::mutator_lock_) {
+    SetField64<false>(GetInstanceFieldOffsetClosure(),
+                      reinterpret_cast<uint64_t>(closure));
+  }
+
+ private:
+  // Instance fields, present in the base class and every generated subclass:
+
+  // private long closure;
+  union {
+    lambda::Closure* actual;
+    uint64_t padding;         // Don't trip up GetObjectSize checks, since the Java code has a long.
+  } closure_;
+
+  // Friends for generating offset tests:
+  friend struct art::LambdaProxyOffsets;              // for verifying offset information
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(LambdaProxy);
+};
+
+}  // namespace mirror
+}  // namespace art
+
+#endif  // ART_RUNTIME_MIRROR_LAMBDA_PROXY_H_