platform_bionic/libc/malloc_debug/malloc_debug.h
Christopher Ferris 72df6708c8 Fix the default alignment of the allocations.
In order to enforce this constraint:

The pointer returned if the allocation succeeds shall be suitably
aligned so that it may be assigned to a pointer to any type of object
and then used to access such an object in the space allocated.

Force all allocations on 32 bit systems to have 8 byte alignment,
and all allocations on 64 bit systems to have 16 byte alignment.

Add a test to verify that the allocator returns the correct alignments.

Bug: 26739265
Change-Id: I9af53279617408676b94e4ec6481b3ed7ffafc6a
2016-02-12 17:30:30 -08:00

73 lines
2.9 KiB
C++

/*
* Copyright (C) 2015 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 MALLOC_DEBUG_H
#define MALLOC_DEBUG_H
#include <stdint.h>
#include <private/bionic_malloc_dispatch.h>
// Allocations that require a header include a variable length header.
// This is the order that data structures will be found. If an optional
// part of the header does not exist, the other parts of the header
// will still be in this order.
// Header (Required)
// BacktraceHeader (Optional: For the allocation backtrace)
// uint8_t data (Optional: Front guard, will be a multiple of MINIMUM_ALIGNMENT_BYTES)
// allocation data
// uint8_t data (Optional: End guard)
//
// If backtracing is enabled, then both BacktraceHeaders will be present.
//
// In the initialization function, offsets into the header will be set
// for each different header location. The offsets are always from the
// beginning of the Header section.
struct Header {
uint32_t tag;
void* orig_pointer;
size_t size;
size_t usable_size;
size_t real_size() const { return size & ~(1U << 31); }
void set_zygote() { size |= 1U << 31; }
static size_t max_size() { return (1U << 31) - 1; }
} __attribute__((packed));
struct BacktraceHeader {
size_t num_frames;
uintptr_t frames[0];
} __attribute__((packed));
constexpr uint32_t DEBUG_TAG = 0x1ee7d00d;
constexpr uint32_t DEBUG_FREE_TAG = 0x1cc7dccd;
constexpr char LOG_DIVIDER[] = "*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***";
constexpr size_t FREE_TRACK_MEM_BUFFER_SIZE = 4096;
extern const MallocDispatch* g_dispatch;
#endif // MALLOC_DEBUG_H