Improve detection of already loaded libraries

Linker is now able to resolve symlinked libraries correctly.

soinfo is extended to save the graph of dependencies during
load/unload. Dependencies are used only in CallConstructor.

Bug: 9741592
Change-Id: Id9c48a74c46aa89bcdf3d54ec2f8ba3d398130b1
diff --git a/linker/linked_list.h b/linker/linked_list.h
new file mode 100644
index 0000000..a6bea6c
--- /dev/null
+++ b/linker/linked_list.h
@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2014 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 __LINKED_LIST_H
+#define __LINKED_LIST_H
+
+#include "private/bionic_macros.h"
+
+template<typename T>
+struct LinkedListEntry {
+  LinkedListEntry<T>* next;
+  T* element;
+};
+
+/*
+ * Represents linked list of objects of type T
+ */
+template<typename T, typename Allocator>
+class LinkedList {
+ public:
+  LinkedList() : head_(nullptr) {}
+
+  void push_front(T* const element) {
+    LinkedListEntry<T>* new_entry = Allocator::alloc();
+    new_entry->next = head_;
+    new_entry->element = element;
+    head_ = new_entry;
+  }
+
+  void clear() {
+    while (head_ != nullptr) {
+      LinkedListEntry<T>* p = head_;
+      head_ = head_->next;
+      Allocator::free(p);
+    }
+  }
+
+  template<typename F>
+  void for_each(F&& action) {
+    for (LinkedListEntry<T>* e = head_; e != nullptr; e = e->next) {
+      if (e->element != nullptr) {
+        action(e->element);
+      }
+    }
+  }
+
+  template<typename F>
+  void remove_if(F&& predicate) {
+    LinkedListEntry<T>* e = head_;
+    for (LinkedListEntry<T>* e = head_; e != nullptr; e = e->next) {
+      if (e->element != nullptr && predicate(e->element)) {
+        e->element = nullptr;
+      }
+    }
+  }
+
+ private:
+  LinkedListEntry<T>* head_;
+  DISALLOW_COPY_AND_ASSIGN(LinkedList);
+};
+
+#endif // __LINKED_LIST_H