upload android base code part3

android/bionic/linker/linker_block_allocator.h

@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef __LINKER_BLOCK_ALLOCATOR_H
+#define __LINKER_BLOCK_ALLOCATOR_H
+
+#include <stdlib.h>
+#include <limits.h>
+#include "private/bionic_macros.h"
+
+struct LinkerBlockAllocatorPage;
+
+/*
+ * This class is a non-template version of the LinkerTypeAllocator
+ * It keeps code inside .cpp file by keeping the interface
+ * template-free.
+ *
+ * Please use LinkerTypeAllocator<type> where possible (everywhere).
+ */
+class LinkerBlockAllocator {
+ public:
+  explicit LinkerBlockAllocator(size_t block_size);
+
+  void* alloc();
+  void free(void* block);
+  void protect_all(int prot);
+
+ private:
+  void create_new_page();
+  LinkerBlockAllocatorPage* find_page(void* block);
+
+  size_t block_size_;
+  LinkerBlockAllocatorPage* page_list_;
+  void* free_block_list_;
+
+  DISALLOW_COPY_AND_ASSIGN(LinkerBlockAllocator);
+};
+
+/*
+ * A simple allocator for the dynamic linker. An allocator allocates instances
+ * of a single fixed-size type. Allocations are backed by page-sized private
+ * anonymous mmaps.
+ *
+ * The differences between this allocator and LinkerMemoryAllocator are:
+ * 1. This allocator manages space more efficiently. LinkerMemoryAllocator
+ *    operates in power-of-two sized blocks up to 1k, when this implementation
+ *    splits the page to aligned size of structure; For example for structures
+ *    with size 513 this allocator will use 516 (520 for lp64) bytes of data
+ *    where generalized implementation is going to use 1024 sized blocks.
+ *
+ * 2. This allocator does not munmap allocated memory, where LinkerMemoryAllocator does.
+ *
+ * 3. This allocator provides mprotect services to the user, where LinkerMemoryAllocator
+ *    always treats it's memory as READ|WRITE.
+ */
+template<typename T>
+class LinkerTypeAllocator {
+ public:
+  LinkerTypeAllocator() : block_allocator_(sizeof(T)) {}
+  T* alloc() { return reinterpret_cast<T*>(block_allocator_.alloc()); }
+  void free(T* t) { block_allocator_.free(t); }
+  void protect_all(int prot) { block_allocator_.protect_all(prot); }
+ private:
+  LinkerBlockAllocator block_allocator_;
+  DISALLOW_COPY_AND_ASSIGN(LinkerTypeAllocator);
+};
+
+#endif // __LINKER_BLOCK_ALLOCATOR_H