Moved escape analysis to reusable module
Rationale:
This prepares other optimizations that
want to do some simple escape analysis.
Also introduces ability for client
to inject a case-specific function.
Test: test-art-host
Change-Id: Ie38a1e24e4479dc40154673db589ec1c82fb73b9
diff --git a/compiler/optimizing/escape.h b/compiler/optimizing/escape.h
new file mode 100644
index 0000000..6514843
--- /dev/null
+++ b/compiler/optimizing/escape.h
@@ -0,0 +1,59 @@
+/*
+ * 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_COMPILER_OPTIMIZING_ESCAPE_H_
+#define ART_COMPILER_OPTIMIZING_ESCAPE_H_
+
+namespace art {
+
+class HInstruction;
+
+/*
+ * Methods related to escape analysis, i.e. determining whether an object
+ * allocation is visible outside ('escapes') its immediate method context.
+ */
+
+/*
+ * Performs escape analysis on the given instruction, typically a reference to an
+ * allocation. The method assigns true to parameter 'is_singleton' if the reference
+ * is the only name that can refer to its value during the lifetime of the method,
+ * meaning that the reference is not aliased with something else, is not stored to
+ * heap memory, and not passed to another method. The method assigns true to parameter
+ * 'is_singleton_and_non_escaping' if the reference is a singleton and is not returned
+ * to the caller or used as an environment local of an HDeoptimize instruction.
+ *
+ * When set, the no_escape function is applied to any use of the allocation instruction
+ * prior to any built-in escape analysis. This allows clients to define better escape
+ * analysis in certain case-specific circumstances. If 'no_escape(reference, user)'
+ * returns true, the user is assumed *not* to cause any escape right away. The return
+ * value false means the client cannot provide a definite answer and built-in escape
+ * analysis is applied to the user instead.
+ */
+void CalculateEscape(HInstruction* reference,
+ bool (*no_escape)(HInstruction*, HInstruction*),
+ /*out*/ bool* is_singleton,
+ /*out*/ bool* is_singleton_and_non_escaping);
+
+/*
+ * Convenience method for testing singleton and non-escaping property at once.
+ * Callers should be aware that this method invokes the full analysis at each call.
+ */
+bool IsNonEscapingSingleton(HInstruction* reference,
+ bool (*no_escape)(HInstruction*, HInstruction*));
+
+} // namespace art
+
+#endif // ART_COMPILER_OPTIMIZING_ESCAPE_H_