platform_bionic/linker/linker_block_allocator.h
Elliott Hughes 5e62b34c0d Clean up bionic_macros.h a bit.
Use <android-base/macros.h> instead where possible, and move the bionic
macros out of the way of the libbase ones. Yes, there are folks who manage
to end up with both included at once (thanks OpenGL!), and cleaning that
up doesn't seem nearly as practical as just making this change.

Bug: N/A
Test: builds
Change-Id: I23fc544f39d5addf81dc61471771a5438778895b
2018-10-25 11:00:00 -07:00

91 lines
3.3 KiB
C++

/*
* 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.
*/
#pragma once
#include <stdlib.h>
#include <limits.h>
#include <android-base/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);
};