source/Target/RegisterContext.cpp

//===-- RegisterContext.cpp -------------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

// C Includes
// C++ Includes
// Other libraries and framework includes
// Project includes
#include "lldb/Target/RegisterContext.h"
#include "lldb/Core/DataExtractor.h"
#include "lldb/Core/RegisterValue.h"
#include "lldb/Core/Scalar.h"
#include "lldb/Host/Endian.h"
#include "lldb/Target/ExecutionContext.h"
#include "lldb/Target/StackFrame.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/Thread.h"

using namespace lldb;
using namespace lldb_private;

RegisterContext::RegisterContext (Thread &thread, uint32_t concrete_frame_idx) :
    m_thread (thread),
    m_concrete_frame_idx (concrete_frame_idx),
    m_stop_id (thread.GetProcess().GetStopID())
{
}

//----------------------------------------------------------------------
// Destructor
//----------------------------------------------------------------------
RegisterContext::~RegisterContext()
{
}

void
RegisterContext::InvalidateIfNeeded (bool force)
{
    const uint32_t this_stop_id = GetStopID();
    const uint32_t process_stop_id = m_thread.GetProcess().GetStopID();    
    if (force || process_stop_id != this_stop_id)
    {
        InvalidateAllRegisters ();
        SetStopID (process_stop_id);
    }
}


const RegisterInfo *
RegisterContext::GetRegisterInfoByName (const char *reg_name, uint32_t start_idx)
{
    if (reg_name && reg_name[0])
    {
        const uint32_t num_registers = GetRegisterCount();
        for (uint32_t reg = start_idx; reg < num_registers; ++reg)
        {
            const RegisterInfo * reg_info = GetRegisterInfoAtIndex(reg);

            if ((reg_info->name != NULL && ::strcasecmp (reg_info->name, reg_name) == 0) ||
                (reg_info->alt_name != NULL && ::strcasecmp (reg_info->alt_name, reg_name) == 0))
            {
                return reg_info;
            }
        }
    }
    return NULL;
}

const char *
RegisterContext::GetRegisterName (uint32_t reg)
{
    const RegisterInfo * reg_info = GetRegisterInfoAtIndex(reg);
    if (reg_info)
        return reg_info->name;
    return NULL;
}

uint64_t
RegisterContext::GetPC(uint64_t fail_value)
{
    uint32_t reg = ConvertRegisterKindToRegisterNumber (eRegisterKindGeneric, LLDB_REGNUM_GENERIC_PC);
    return ReadRegisterAsUnsigned (reg, fail_value);
}

bool
RegisterContext::SetPC(uint64_t pc)
{
    uint32_t reg = ConvertRegisterKindToRegisterNumber (eRegisterKindGeneric, LLDB_REGNUM_GENERIC_PC);
    bool success = WriteRegisterFromUnsigned (reg, pc);
    if (success)
    {
        StackFrameSP frame_sp(m_thread.GetFrameWithConcreteFrameIndex (m_concrete_frame_idx));
        if (frame_sp)
            frame_sp->ChangePC(pc);
        else
            m_thread.ClearStackFrames ();
    }
    return success;
}

uint64_t
RegisterContext::GetSP(uint64_t fail_value)
{
    uint32_t reg = ConvertRegisterKindToRegisterNumber (eRegisterKindGeneric, LLDB_REGNUM_GENERIC_SP);
    return ReadRegisterAsUnsigned (reg, fail_value);
}

bool
RegisterContext::SetSP(uint64_t sp)
{
    uint32_t reg = ConvertRegisterKindToRegisterNumber (eRegisterKindGeneric, LLDB_REGNUM_GENERIC_SP);
    return WriteRegisterFromUnsigned (reg, sp);
}

uint64_t
RegisterContext::GetFP(uint64_t fail_value)
{
    uint32_t reg = ConvertRegisterKindToRegisterNumber (eRegisterKindGeneric, LLDB_REGNUM_GENERIC_FP);
    return ReadRegisterAsUnsigned (reg, fail_value);
}

bool
RegisterContext::SetFP(uint64_t fp)
{
    uint32_t reg = ConvertRegisterKindToRegisterNumber (eRegisterKindGeneric, LLDB_REGNUM_GENERIC_FP);
    return WriteRegisterFromUnsigned (reg, fp);
}

uint64_t
RegisterContext::GetReturnAddress (uint64_t fail_value)
{
    uint32_t reg = ConvertRegisterKindToRegisterNumber (eRegisterKindGeneric, LLDB_REGNUM_GENERIC_RA);
    return ReadRegisterAsUnsigned (reg, fail_value);
}

uint64_t
RegisterContext::GetFlags (uint64_t fail_value)
{
    uint32_t reg = ConvertRegisterKindToRegisterNumber (eRegisterKindGeneric, LLDB_REGNUM_GENERIC_FLAGS);
    return ReadRegisterAsUnsigned (reg, fail_value);
}


uint64_t
RegisterContext::ReadRegisterAsUnsigned (uint32_t reg, uint64_t fail_value)
{
    if (reg != LLDB_INVALID_REGNUM)
    {
        const RegisterInfo *reg_info = GetRegisterInfoAtIndex (reg);
        if (reg_info)
        {
            RegisterValue value;
            if (ReadRegister (reg_info, value))
                return value.GetAsUInt64();
        }
    }
    return fail_value;
}

bool
RegisterContext::WriteRegisterFromUnsigned (uint32_t reg, uint64_t uval)
{
    if (reg == LLDB_INVALID_REGNUM)
        return false;
    const RegisterInfo *reg_info = GetRegisterInfoAtIndex (reg);
    if (reg_info)
    {
        RegisterValue value;
        if (value.SetUInt(uval, reg_info->byte_size))
            return WriteRegister (reg_info, value);
    }
    return false;
}

lldb::tid_t
RegisterContext::GetThreadID() const
{
    return m_thread.GetID();
}

uint32_t
RegisterContext::NumSupportedHardwareBreakpoints ()
{
    return 0;
}

uint32_t
RegisterContext::SetHardwareBreakpoint (lldb::addr_t addr, size_t size)
{
    return LLDB_INVALID_INDEX32;
}

bool
RegisterContext::ClearHardwareBreakpoint (uint32_t hw_idx)
{
    return false;
}


uint32_t
RegisterContext::NumSupportedHardwareWatchpoints ()
{
    return 0;
}

uint32_t
RegisterContext::SetHardwareWatchpoint (lldb::addr_t addr, size_t size, bool read, bool write)
{
    return LLDB_INVALID_INDEX32;
}

bool
RegisterContext::ClearHardwareWatchpoint (uint32_t hw_index)
{
    return false;
}

bool
RegisterContext::HardwareSingleStep (bool enable)
{
    return false;
}

Error
RegisterContext::ReadRegisterValueFromMemory (const RegisterInfo *reg_info,
                                              lldb::addr_t src_addr, 
                                              uint32_t src_len, 
                                              RegisterValue &reg_value)
{
    Error error;
    if (reg_info == NULL)
    {
        error.SetErrorString ("invalid register info argument.");
        return error;
    }

    
    // Moving from addr into a register
    //
    // Case 1: src_len == dst_len
    //
    //   |AABBCCDD| Address contents
    //   |AABBCCDD| Register contents
    //
    // Case 2: src_len > dst_len
    //
    //   Error!  (The register should always be big enough to hold the data)
    //
    // Case 3: src_len < dst_len
    //
    //   |AABB| Address contents
    //   |AABB0000| Register contents [on little-endian hardware]
    //   |0000AABB| Register contents [on big-endian hardware]
    if (src_len > RegisterValue::kMaxRegisterByteSize)
    {
        error.SetErrorString ("register too small to receive memory data");
        return error;
    }
    
    const uint32_t dst_len = reg_info->byte_size;
    
    if (src_len > dst_len)
    {
        error.SetErrorStringWithFormat("%u bytes is too big to store in register %s (%u bytes)", src_len, reg_info->name, dst_len);
        return error;
    }
    
    Process &process = m_thread.GetProcess();
    uint8_t src[RegisterValue::kMaxRegisterByteSize];
   
    // Read the memory
    const uint32_t bytes_read = process.ReadMemory (src_addr, src, src_len, error);

    // Make sure the memory read succeeded...
    if (bytes_read != src_len)
    {
        if (error.Success())
        {
            // This might happen if we read _some_ bytes but not all
            error.SetErrorStringWithFormat("read %u of %u bytes", bytes_read, src_len);
        }
        return error;
    }
    
    // We now have a memory buffer that contains the part or all of the register
    // value. Set the register value using this memory data.
    // TODO: we might need to add a parameter to this function in case the byte
    // order of the memory data doesn't match the process. For now we are assuming
    // they are the same.
    reg_value.SetFromMemoryData (reg_info, 
                                 src, 
                                 src_len, 
                                 process.GetByteOrder(), 
                                 error);
    return error;
}

Error
RegisterContext::WriteRegisterValueToMemory (const RegisterInfo *reg_info,
                                             lldb::addr_t dst_addr, 
                                             uint32_t dst_len, 
                                             const RegisterValue &reg_value)
{
    
    uint8_t dst[RegisterValue::kMaxRegisterByteSize];

    Error error;

    Process &process = m_thread.GetProcess();

    // TODO: we might need to add a parameter to this function in case the byte
    // order of the memory data doesn't match the process. For now we are assuming
    // they are the same.

    const uint32_t bytes_copied = reg_value.GetAsMemoryData (reg_info, 
                                                             dst, 
                                                             dst_len, 
                                                             process.GetByteOrder(), 
                                                             error);

    if (error.Success())
    {
        if (bytes_copied == 0)
        {
            error.SetErrorString("byte copy failed.");
        }
        else
        {
            const uint32_t bytes_written = process.WriteMemory (dst_addr, dst, bytes_copied, error);
            if (bytes_written != bytes_copied)
            {
                if (error.Success())
                {
                    // This might happen if we read _some_ bytes but not all
                    error.SetErrorStringWithFormat("only wrote %u of %u bytes", bytes_written, bytes_copied);
                }
            }
        }
    }

    return error;

}

Target *
RegisterContext::CalculateTarget ()
{
    return m_thread.CalculateTarget();
}


Process *
RegisterContext::CalculateProcess ()
{
    return m_thread.CalculateProcess ();
}

Thread *
RegisterContext::CalculateThread ()
{
    return &m_thread;
}

StackFrame *
RegisterContext::CalculateStackFrame ()
{
    // Register contexts might belong to many frames if we have inlined 
    // functions inside a frame since all inlined functions share the
    // same registers, so we can't definitively say which frame we come from...
    return NULL;
}

void
RegisterContext::CalculateExecutionContext (ExecutionContext &exe_ctx)
{
    m_thread.CalculateExecutionContext (exe_ctx);
}


bool
RegisterContext::ConvertBetweenRegisterKinds (int source_rk, uint32_t source_regnum, int target_rk, uint32_t& target_regnum)
{
    const uint32_t num_registers = GetRegisterCount();
    for (uint32_t reg = 0; reg < num_registers; ++reg)
    {
        const RegisterInfo * reg_info = GetRegisterInfoAtIndex (reg);

        if (reg_info->kinds[source_rk] == source_regnum)
        {
            target_regnum = reg_info->kinds[target_rk];
            if (target_regnum == LLDB_INVALID_REGNUM)
            {
                return false;
            }
            else
            {
                return true;
            }
        } 
    }
    return false;
}

//bool
//RegisterContext::ReadRegisterValue (uint32_t reg, Scalar &value)
//{
//    DataExtractor data;
//    if (!ReadRegisterBytes (reg, data))
//        return false;
//
//    const RegisterInfo *reg_info = GetRegisterInfoAtIndex (reg);
//    uint32_t offset = 0;
//    switch (reg_info->encoding)
//    {
//    case eEncodingInvalid:
//    case eEncodingVector:
//        break;
//
//    case eEncodingUint:
//        switch (reg_info->byte_size)
//        {
//        case 1:
//            {
//                value = data.GetU8 (&offset);
//                return true;
//            }
//        case 2:
//            {
//                value = data.GetU16 (&offset);
//                return true;
//            }
//        case 4:
//            {
//                value = data.GetU32 (&offset);
//                return true;
//            }
//        case 8:
//            {
//                value = data.GetU64 (&offset);
//                return true;
//            }
//        }
//        break;
//    case eEncodingSint:
//        switch (reg_info->byte_size)
//        {
//        case 1:
//            {
//                int8_t v;
//                if (data.ExtractBytes (0, sizeof (int8_t), lldb::endian::InlHostByteOrder(), &v) != sizeof (int8_t))
//                    return false;
//                value = v;
//                return true;
//            }
//        case 2:
//            {
//                int16_t v;
//                if (data.ExtractBytes (0, sizeof (int16_t), lldb::endian::InlHostByteOrder(), &v) != sizeof (int16_t))
//                    return false;
//                value = v;
//                return true;
//            }
//        case 4:
//            {
//                int32_t v;
//                if (data.ExtractBytes (0, sizeof (int32_t), lldb::endian::InlHostByteOrder(), &v) != sizeof (int32_t))
//                    return false;
//                value = v;
//                return true;
//            }
//        case 8:
//            {
//                int64_t v;
//                if (data.ExtractBytes (0, sizeof (int64_t), lldb::endian::InlHostByteOrder(), &v) != sizeof (int64_t))
//                    return false;
//                value = v;
//                return true;
//            }
//        }
//        break;
//    case eEncodingIEEE754:
//        switch (reg_info->byte_size)
//        {
//        case sizeof (float):
//            {
//                float v;
//                if (data.ExtractBytes (0, sizeof (float), lldb::endian::InlHostByteOrder(), &v) != sizeof (float))
//                    return false;
//                value = v;
//                return true;
//            }
//        case sizeof (double):
//            {
//                double v;
//                if (data.ExtractBytes (0, sizeof (double), lldb::endian::InlHostByteOrder(), &v) != sizeof (double))
//                    return false;
//                value = v;
//                return true;
//            }
//        case sizeof (long double):
//            {
//                double v;
//                if (data.ExtractBytes (0, sizeof (long double), lldb::endian::InlHostByteOrder(), &v) != sizeof (long double))
//                    return false;
//                value = v;
//                return true;
//            }
//        }
//        break;
//    }
//    return false;
//}
//
//bool 
//RegisterContext::WriteRegisterValue (uint32_t reg, const Scalar &value)
//{
//    DataExtractor data;
//    if (!value.IsValid())
//        return false;
//    if (!value.GetData (data))
//        return false;
//
//    return WriteRegisterBytes (reg, data);
//}