lambda: Infrastructure to support capture/liberate-variable dex opcodes

* ArtLambdaMethod - wrap an ArtMethod with extra runtime lambda info
* Closure - data representation for a runtime lambda closure (read-only)
* ClosureBuilder - writer for creating a Closure at runtime
* ShortyFieldType - char/enum wrapper for shorty_field_type in dex

Tests:
* Closure, ClosureBuilder, ShortyFieldType have full unit test coverage.
* ArtLambdaMethod does not, but it is tested indirectly and is otherwise
  trivial getters.

Future CLs will include interpreter integration with minimal changes to
this Closure infrastructure.

Change-Id: I38a7aea8df1da7b154fd6623258c6c228c8e51df

1 files changed, 77 insertions, 0 deletions

diff --git a/runtime/lambda/art_lambda_method.cc b/runtime/lambda/art_lambda_method.cc
new file mode 100644
index 0000000000..6f9f8bbb59
--- /dev/null
+++ b/runtime/lambda/art_lambda_method.cc
@@ -0,0 +1,77 @@
+/*
+ * 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.
+ */
+
+#include "lambda/art_lambda_method.h"
+
+#include "base/logging.h"
+#include "lambda/shorty_field_type.h"
+
+namespace art {
+namespace lambda {
+
+ArtLambdaMethod::ArtLambdaMethod(ArtMethod* target_method,
+                                 const char* captured_variables_type_descriptor,
+                                 const char* captured_variables_shorty,
+                                 bool innate_lambda)
+    : method_(target_method),
+      captured_variables_type_descriptor_(captured_variables_type_descriptor),
+      captured_variables_shorty_(captured_variables_shorty),
+      innate_lambda_(innate_lambda) {
+  DCHECK(target_method != nullptr);
+  DCHECK(captured_variables_type_descriptor != nullptr);
+  DCHECK(captured_variables_shorty != nullptr);
+
+  // Calculate the static closure size from the captured variables.
+  size_t size = sizeof(ArtLambdaMethod*);  // Initial size is just this method.
+  bool static_size = true;
+  const char* shorty = captured_variables_shorty_;
+  while (shorty != nullptr && *shorty != '\0') {
+    // Each captured variable also appends to the size.
+    ShortyFieldType shorty_field{*shorty};  // NOLINT [readability/braces] [4]
+    size += shorty_field.GetStaticSize();
+    static_size &= shorty_field.IsStaticSize();
+    ++shorty;
+  }
+  closure_size_ = size;
+
+  // We determine whether or not the size is dynamic by checking for nested lambdas.
+  //
+  // This is conservative, since in theory an optimization could determine the size
+  // of the nested lambdas recursively. In practice it's probably better to flatten out
+  // nested lambdas and inline all their code if they are known statically.
+  dynamic_size_ = !static_size;
+
+  if (kIsDebugBuild) {
+    // Double check that the number of captured variables match in both strings.
+    size_t shorty_count = strlen(captured_variables_shorty);
+
+    size_t long_count = 0;
+    const char* long_type = captured_variables_type_descriptor;
+    ShortyFieldType out;
+    while ((long_type = ShortyFieldType::ParseFromFieldTypeDescriptor(long_type, &out))
+           != nullptr) {
+      ++long_count;
+    }
+
+    DCHECK_EQ(shorty_count, long_count)
+        << "number of captured variables in long type '" << captured_variables_type_descriptor
+        << "' (" << long_count << ")" << " did not match short type '"
+        << captured_variables_shorty << "' (" << shorty_count << ")";
+  }
+}
+
+}  // namespace lambda
+}  // namespace art