Move JIT debugger interface code to its own file.

Change-Id: Ie788daa8caf60f2f0f93484681a8a9fcce61c23f
diff --git a/runtime/jit/debugger_interface.cc b/runtime/jit/debugger_interface.cc
new file mode 100644
index 0000000..3c2898b
--- /dev/null
+++ b/runtime/jit/debugger_interface.cc
@@ -0,0 +1,97 @@
+/*
+ * 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 "debugger_interface.h"
+
+namespace art {
+
+// -------------------------------------------------------------------
+// Binary GDB JIT Interface as described in
+//   http://sourceware.org/gdb/onlinedocs/gdb/Declarations.html
+// -------------------------------------------------------------------
+extern "C" {
+  typedef enum {
+    JIT_NOACTION = 0,
+    JIT_REGISTER_FN,
+    JIT_UNREGISTER_FN
+  } JITAction;
+
+  struct JITCodeEntry {
+    JITCodeEntry* next_;
+    JITCodeEntry* prev_;
+    const uint8_t *symfile_addr_;
+    uint64_t symfile_size_;
+  };
+
+  struct JITDescriptor {
+    uint32_t version_;
+    uint32_t action_flag_;
+    JITCodeEntry* relevant_entry_;
+    JITCodeEntry* first_entry_;
+  };
+
+  // GDB will place breakpoint into this function.
+  // To prevent GCC from inlining or removing it we place noinline attribute
+  // and inline assembler statement inside.
+  void __attribute__((noinline)) __jit_debug_register_code();
+  void __attribute__((noinline)) __jit_debug_register_code() {
+    __asm__("");
+  }
+
+  // GDB will inspect contents of this descriptor.
+  // Static initialization is necessary to prevent GDB from seeing
+  // uninitialized descriptor.
+  JITDescriptor __jit_debug_descriptor = { 1, JIT_NOACTION, nullptr, nullptr };
+}
+
+JITCodeEntry* CreateJITCodeEntry(const uint8_t *symfile_addr, uintptr_t symfile_size) {
+  JITCodeEntry* entry = new JITCodeEntry;
+  entry->symfile_addr_ = symfile_addr;
+  entry->symfile_size_ = symfile_size;
+  entry->prev_ = nullptr;
+
+  // TODO: Do we need a lock here?
+  entry->next_ = __jit_debug_descriptor.first_entry_;
+  if (entry->next_ != nullptr) {
+    entry->next_->prev_ = entry;
+  }
+  __jit_debug_descriptor.first_entry_ = entry;
+  __jit_debug_descriptor.relevant_entry_ = entry;
+
+  __jit_debug_descriptor.action_flag_ = JIT_REGISTER_FN;
+  __jit_debug_register_code();
+  return entry;
+}
+
+void DeleteJITCodeEntry(JITCodeEntry* entry) {
+  // TODO: Do we need a lock here?
+  if (entry->prev_ != nullptr) {
+    entry->prev_->next_ = entry->next_;
+  } else {
+    __jit_debug_descriptor.first_entry_ = entry->next_;
+  }
+
+  if (entry->next_ != nullptr) {
+    entry->next_->prev_ = entry->prev_;
+  }
+
+  __jit_debug_descriptor.relevant_entry_ = entry;
+  __jit_debug_descriptor.action_flag_ = JIT_UNREGISTER_FN;
+  __jit_debug_register_code();
+  delete entry;
+}
+
+}  // namespace art