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Improve instruction emulation based stack unwinding 

On ARM there is no difference petween a pop and a load instruction so
a register can be loaded multiple times during the function. Add check
to threat the load as a restore only if it do the restore from the
same location where the register was saved.

Differential revision: http://reviews.llvm.org/D11947

llvm-svn: 245546
This commit is contained in:
Tamas Berghammer 2015-08-20 09:09:01 +00:00
parent 0e1d729b75
commit 99c40e673a
3 changed files with 24 additions and 10 deletions
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11
lldb/source/Plugins/Instruction/ARM/EmulateInstructionARM.cpp
View File

@ -578,7 +578,7 @@ EmulateInstructionARM::EmulatePOP (const uint32_t opcode, const ARMEncoding enco
{
if (BitIsSet (registers, i))
{
context.SetRegisterPlusOffset (sp_reg, addr - sp);
context.SetAddress(addr);
data = MemARead(context, addr, 4, 0, &success);
if (!success)
return false;
@ -2214,7 +2214,7 @@ EmulateInstructionARM::EmulateVPOP (const uint32_t opcode, const ARMEncoding enc
for (i=0; i<regs; ++i)
{
GetRegisterInfo (eRegisterKindDWARF, start_reg + d + i, dwarf_reg);
context.SetRegisterPlusOffset (sp_reg, addr - sp);
context.SetAddress(addr);
data = MemARead(context, addr, reg_byte_size, 0, &success);
if (!success)
return false;
@ -3516,7 +3516,10 @@ EmulateInstructionARM::EmulateLDM (const uint32_t opcode, const ARMEncoding enco
context.type = EmulateInstruction::eContextRegisterPlusOffset;
context.SetRegisterPlusOffset (dwarf_reg, offset);
if (wback && (n == 13)) // Pop Instruction
{
context.type = EmulateInstruction::eContextPopRegisterOffStack;
context.SetAddress(base_address + offset);
}
// R[i] = MemA [address, 4]; address = address + 4;
uint32_t data = MemARead (context, base_address + offset, addr_byte_size, 0, &success);
@ -10307,7 +10310,7 @@ EmulateInstructionARM::EmulateLDRDImmediate (const uint32_t opcode, const ARMEnc
context.type = eContextPopRegisterOffStack;
else
context.type = eContextRegisterLoad;
context.SetRegisterPlusOffset (base_reg, address - Rn);
context.SetAddress(address);
const uint32_t addr_byte_size = GetAddressByteSize();
uint32_t data = MemARead (context, address, addr_byte_size, 0, &success);
@ -10437,7 +10440,7 @@ EmulateInstructionARM::EmulateLDRDRegister (const uint32_t opcode, const ARMEnco
context.type = eContextPopRegisterOffStack;
else
context.type = eContextRegisterLoad;
context.SetRegisterPlusIndirectOffset (base_reg, offset_reg);
context.SetAddress(address);
// R[t] = MemA[address,4];
const uint32_t addr_byte_size = GetAddressByteSize();

10
lldb/source/Plugins/Instruction/ARM64/EmulateInstructionARM64.cpp
View File

@ -768,8 +768,6 @@ EmulateInstructionARM64::EmulateLDPSTP (const uint32_t opcode)
Context context_t;
Context context_t2;
context_t.SetRegisterToRegisterPlusOffset (reg_info_Rt, reg_info_base, 0);
context_t2.SetRegisterToRegisterPlusOffset (reg_info_Rt2, reg_info_base, size);
uint8_t buffer [RegisterValue::kMaxRegisterByteSize];
Error error;
@ -787,6 +785,8 @@ EmulateInstructionARM64::EmulateLDPSTP (const uint32_t opcode)
context_t.type = eContextRegisterStore;
context_t2.type = eContextRegisterStore;
}
context_t.SetRegisterToRegisterPlusOffset (reg_info_Rt, reg_info_base, 0);
context_t2.SetRegisterToRegisterPlusOffset (reg_info_Rt2, reg_info_base, size);
if (!ReadRegister (&reg_info_Rt, data_Rt))
return false;
@ -820,6 +820,8 @@ EmulateInstructionARM64::EmulateLDPSTP (const uint32_t opcode)
context_t.type = eContextRegisterLoad;
context_t2.type = eContextRegisterLoad;
}
context_t.SetAddress(address);
context_t2.SetAddress(address + size);
if (rt_unknown)
memset (buffer, 'U', reg_info_Rt.byte_size);
@ -950,8 +952,6 @@ EmulateInstructionARM64::EmulateLDRSTRImm (const uint32_t opcode)
return false;
Context context;
context.SetRegisterToRegisterPlusOffset (reg_info_Rt, reg_info_base, postindex ? 0 : offset);
switch (memop)
{
case MemOp_STORE:
@ -959,6 +959,7 @@ EmulateInstructionARM64::EmulateLDRSTRImm (const uint32_t opcode)
context.type = eContextPushRegisterOnStack;
else
context.type = eContextRegisterStore;
context.SetRegisterToRegisterPlusOffset (reg_info_Rt, reg_info_base, postindex ? 0 : offset);
if (!ReadRegister (&reg_info_Rt, data_Rt))
return false;
@ -975,6 +976,7 @@ EmulateInstructionARM64::EmulateLDRSTRImm (const uint32_t opcode)
context.type = eContextPopRegisterOffStack;
else
context.type = eContextRegisterLoad;
context.SetAddress(address);
if (!ReadMemory (context, address, buffer, reg_info_Rt.byte_size))
return false;

13
lldb/source/Plugins/UnwindAssembly/InstEmulation/UnwindAssemblyInstEmulation.cpp
View File

@ -580,8 +580,17 @@ UnwindAssemblyInstEmulation::WriteRegister (EmulateInstruction *instruction,
const uint32_t generic_regnum = reg_info->kinds[eRegisterKindGeneric];
if (reg_num != LLDB_INVALID_REGNUM && generic_regnum != LLDB_REGNUM_GENERIC_SP)
{
m_curr_row->SetRegisterLocationToSame (reg_num, /*must_replace*/ false);
m_curr_row_modified = true;
if (context.info_type == EmulateInstruction::eInfoTypeAddress)
{
if (m_pushed_regs.find (reg_num) != m_pushed_regs.end () &&
context.info.address == m_pushed_regs[reg_num])
{
m_curr_row->SetRegisterLocationToSame (reg_num, /*must_replace*/ false);
m_curr_row_modified = true;
}
}
else
assert (!"unhandled case, add code to handle this!");
}
}
}