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/*
* Copyright (c) 2010, 2014, Oracle and/or its affiliates. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; version 2 of the
* License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*/
#include "base/debugging.h"
#if defined(_WIN32) && defined(_DEBUG)
#include <windows.h>
#include <stdexcept>
//--------------------------------------------------------------------------------------------------
DataBreakpoint::DataBreakpoint()
{
_register_index = -1;
}
//--------------------------------------------------------------------------------------------------
DataBreakpoint::~DataBreakpoint()
{
Clear();
}
//--------------------------------------------------------------------------------------------------
/**
* Used to set the given value into target.
*
* @param target The target value to modify.
* @param offset Bit offset in the target, counted from LSB.
* @param bits Number of bits to set with value.
* @value The new value to set.
*/
void DataBreakpoint::SetBits(REGISTER_TYPE& target, REGISTER_TYPE offset, REGISTER_TYPE bits, REGISTER_TYPE value)
{
REGISTER_TYPE mask = (1 << bits) - 1;
target = (target & ~(mask << offset)) | (value << offset);
}
//--------------------------------------------------------------------------------------------------
/**
* Sets a data watch for the given address.
*
* @address The location to watch.
* @size The size of the memory block address points to. Can be 1, 2 or 4 bytes.
* @when Determines when to trigger the break point (write or read/write).
*/
void DataBreakpoint::Set(void* address, int size, Condition when)
{
if (_register_index != -1)
throw std::runtime_error("Watch point already set. Use clear() before setting a new one.");
switch (size)
{
case 1:
size = 0;
break;
case 2:
size = 1;
break;
case 4:
size = 3;
break;
default:
throw std::runtime_error("Invalid data length for watch point specified.");
}
HANDLE currentThread = GetCurrentThread();
// Set up the thread context for this watch point.
CONTEXT context;
context.ContextFlags = CONTEXT_DEBUG_REGISTERS;
// Read the register values
if (!GetThreadContext(currentThread, &context))
throw std::runtime_error("Failed getting the current thread context.");
// Find an available hardware register.
for (_register_index = 0; _register_index < 4; ++_register_index)
{
if ((context.Dr7 & (REGISTER_TYPE)(1 << (2 * _register_index))) == 0)
break;
}
if (_register_index >= 4)
throw std::runtime_error("Could not find a free hardware register.");
switch (_register_index)
{
case 0:
context.Dr0 = (REGISTER_TYPE)address;
break;
case 1:
context.Dr1 = (REGISTER_TYPE)address;
break;
case 2:
context.Dr2 = (REGISTER_TYPE)address;
break;
case 3:
context.Dr3 = (REGISTER_TYPE)address;
break;
}
SetBits(context.Dr7, 16 + (4 * _register_index), 2, when);
SetBits(context.Dr7, 18 + (4 * _register_index), 2, size);
SetBits(context.Dr7, 2 * _register_index, 1, 1);
if (!SetThreadContext(currentThread, &context))
throw std::runtime_error("Could not set modified thread context for the watch point.");
}
//--------------------------------------------------------------------------------------------------
/**
* Removes a currently set watch point if one is set.
*/
void DataBreakpoint::Clear()
{
if (_register_index != -1)
{
CONTEXT context;
HANDLE currentThread = GetCurrentThread();
context.ContextFlags = CONTEXT_DEBUG_REGISTERS;
if (!GetThreadContext(currentThread, &context))
throw std::runtime_error("Failed getting the current thread context.");
// Reset debug register settings for this watch point.
if (_register_index < 0 && _register_index >= 4)
throw std::runtime_error("Internal error: debug register index is wrong.");
SetBits(context.Dr7, 2 * _register_index, 1, 0);
if (!SetThreadContext(currentThread, &context))
throw std::runtime_error("Could not set modified thread context for the watch point.");
_register_index = -1;
}
}
//--------------------------------------------------------------------------------------------------
#endif // _DEBUG
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