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Fix register read callback in linux-arm single stepping 

The previous read callback always read the value of the register what
caused problems when the emulator wrote some value into a register and
then expected to read the same value back. This CL add a register value
cache into the callbacks to return the correct value after a register
write also.

Test Plan: Stepping over BL/BLX instruction works on android-arm if the instruction set isn't change (other, unrelated patch will come for the case when we move to an other instruction set)

Reviewers: omjavaid, sas, clayborg

Reviewed By: clayborg

Subscribers: labath, tberghammer, rengolin, aemerson, lldb-commits

Differential Revision: http://reviews.llvm.org/D9187

From: Tamas Berghammer <tberghammer@google.com>
llvm-svn: 235852
This commit is contained in:
Pavel Labath 2015-04-27 09:21:14 +00:00
parent 53ffb319d1
commit 6648fcc34b
1 changed files with 33 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

54
lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
View File

@ -2738,10 +2738,11 @@ struct EmulatorBaton
{
NativeProcessLinux* m_process;
NativeRegisterContext* m_reg_context;
RegisterValue m_pc;
RegisterValue m_flags;
EmulatorBaton(NativeProcessLinux* process, NativeRegisterContext* reg_context) :
// eRegisterKindDWARF -> RegsiterValue
std::unordered_map<uint32_t, RegisterValue> m_register_values;
EmulatorBaton(NativeProcessLinux* process, NativeRegisterContext* reg_context) :
m_process(process), m_reg_context(reg_context) {}
};
@ -2770,6 +2771,13 @@ ReadRegisterCallback (EmulateInstruction *instruction,
{
EmulatorBaton* emulator_baton = static_cast<EmulatorBaton*>(baton);
auto it = emulator_baton->m_register_values.find(reg_info->kinds[eRegisterKindDWARF]);
if (it != emulator_baton->m_register_values.end())
{
reg_value = it->second;
return true;
}
// The emulator only fill in the dwarf regsiter numbers (and in some case
// the generic register numbers). Get the full register info from the
// register context based on the dwarf register numbers.
@ -2777,7 +2785,12 @@ ReadRegisterCallback (EmulateInstruction *instruction,
eRegisterKindDWARF, reg_info->kinds[eRegisterKindDWARF]);
Error error = emulator_baton->m_reg_context->ReadRegister(full_reg_info, reg_value);
return error.Success();
if (error.Success())
{
emulator_baton->m_register_values[reg_info->kinds[eRegisterKindDWARF]] = reg_value;
return true;
}
return false;
}
static bool
@ -2788,17 +2801,7 @@ WriteRegisterCallback (EmulateInstruction *instruction,
const RegisterValue &reg_value)
{
EmulatorBaton* emulator_baton = static_cast<EmulatorBaton*>(baton);
switch (reg_info->kinds[eRegisterKindGeneric])
{
case LLDB_REGNUM_GENERIC_PC:
emulator_baton->m_pc = reg_value;
break;
case LLDB_REGNUM_GENERIC_FLAGS:
emulator_baton->m_flags = reg_value;
break;
}
emulator_baton->m_register_values[reg_info->kinds[eRegisterKindDWARF]] = reg_value;
return true;
}
@ -2843,17 +2846,27 @@ NativeProcessLinux::SetupSoftwareSingleStepping(NativeThreadProtocolSP thread_sp
if (!emulator_ap->ReadInstruction())
return Error("Read instruction failed!");
bool emulation_result = emulator_ap->EvaluateInstruction(eEmulateInstructionOptionAutoAdvancePC);
const RegisterInfo* reg_info_pc = register_context_sp->GetRegisterInfo(eRegisterKindGeneric, LLDB_REGNUM_GENERIC_PC);
const RegisterInfo* reg_info_flags = register_context_sp->GetRegisterInfo(eRegisterKindGeneric, LLDB_REGNUM_GENERIC_FLAGS);
auto pc_it = baton.m_register_values.find(reg_info_pc->kinds[eRegisterKindDWARF]);
auto flags_it = baton.m_register_values.find(reg_info_flags->kinds[eRegisterKindDWARF]);
lldb::addr_t next_pc;
lldb::addr_t next_flags;
if (emulator_ap->EvaluateInstruction(eEmulateInstructionOptionAutoAdvancePC))
if (emulation_result)
{
next_pc = baton.m_pc.GetAsUInt64();
if (baton.m_flags.GetType() != RegisterValue::eTypeInvalid)
next_flags = baton.m_flags.GetAsUInt32();
assert(pc_it != baton.m_register_values.end() && "Emulation was successfull but PC wasn't updated");
next_pc = pc_it->second.GetAsUInt64();
if (flags_it != baton.m_register_values.end())
next_flags = flags_it->second.GetAsUInt64();
else
next_flags = ReadFlags (register_context_sp.get());
}
else if (baton.m_pc.GetType() == RegisterValue::eTypeInvalid)
else if (pc_it == baton.m_register_values.end())
{
// Emulate instruction failed and it haven't changed PC. Advance PC
// with the size of the current opcode because the emulation of all
@ -2889,7 +2902,6 @@ NativeProcessLinux::SetupSoftwareSingleStepping(NativeThreadProtocolSP thread_sp
error = SetSoftwareBreakpoint(next_pc, 0);
}
if (error.Fail())
return error;