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Fix ARM instruction emulation tests on big-endian systems
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Running the ARM instruction emulation test on a big-endian system
would fail, since the code doesn't respect endianness properly.

In EmulateInstructionARM::TestEmulation, code assumes that an
instruction opcode read in from the test file is in target byte
order, but it was in fact read in in host byte order.

More difficult to fix, the EmulationStateARM structure models
the overlapping sregs and dregs by a union in _sd_regs.  This
only works correctly if the host is a little-endian system.
I've removed the union in favor of a simple array containing
the 32 sregs, and changed any code accessing dregs to explicitly
use the correct two sregs overlaying that dreg in the proper
target order.

Also, the EmulationStateARM::ReadPseudoMemory and WritePseudoMemory
track memory as a map of uint32_t values in host byte order, and
implement 64-bit memory accessing by splitting them up into two
uint32_t ones.  However, callers expect memory contents to be
provided in the form of a byte array (in target byte order).
This means the uint32_t contents need to be byte-swapped on
BE systems, and when splitting up a 64-bit access into two 32-bit
ones, byte order has to be respected.

Differential Revision: http://reviews.llvm.org/D18984

llvm-svn: 266314
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@uweigand
uweigand committed Apr 14, 2016
1 parent 0501eeb commit 91a2ad1
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Showing 3 changed files with 70 additions and 62 deletions.
6 changes: 3 additions & 3 deletions lldb/source/Plugins/Instruction/ARM/EmulateInstructionARM.cpp
View file
Expand Up @@ -13683,14 +13683,14 @@ EmulateInstructionARM::TestEmulation (Stream *out_stream, ArchSpec &arch, Option
{
m_opcode_mode = eModeThumb;
if (test_opcode < 0x10000)
m_opcode.SetOpcode16 (test_opcode, GetByteOrder());
m_opcode.SetOpcode16 (test_opcode, endian::InlHostByteOrder());
else
m_opcode.SetOpcode32 (test_opcode, GetByteOrder());
m_opcode.SetOpcode32 (test_opcode, endian::InlHostByteOrder());
}
else if (arch.GetTriple().getArch() == llvm::Triple::arm)
{
m_opcode_mode = eModeARM;
m_opcode.SetOpcode32 (test_opcode, GetByteOrder());
m_opcode.SetOpcode32 (test_opcode, endian::InlHostByteOrder());
}
else
{
Expand Down
116 changes: 64 additions & 52 deletions lldb/source/Plugins/Instruction/ARM/EmulationStateARM.cpp
View file
Expand Up @@ -61,11 +61,15 @@ EmulationStateARM::LoadPseudoRegistersFromFrame (StackFrame &frame)

if (reg_ctx->ReadRegister (reg_info, reg_value))
{
uint64_t value = reg_value.GetAsUInt64();
uint32_t idx = i - dwarf_d0;
if (i < 16)
m_vfp_regs.sd_regs[idx].d_reg = reg_value.GetAsUInt64();
{
m_vfp_regs.s_regs[idx * 2] = (uint32_t)value;
m_vfp_regs.s_regs[idx * 2 + 1] = (uint32_t)(value >> 32);
}
else
m_vfp_regs.d_regs[idx - 16] = reg_value.GetAsUInt64();
m_vfp_regs.d_regs[idx - 16] = value;
}
else
success = false;
Expand All @@ -82,16 +86,18 @@ EmulationStateARM::StorePseudoRegisterValue (uint32_t reg_num, uint64_t value)
else if ((dwarf_s0 <= reg_num) && (reg_num <= dwarf_s31))
{
uint32_t idx = reg_num - dwarf_s0;
m_vfp_regs.sd_regs[idx / 2].s_reg[idx % 2] = (uint32_t) value;
m_vfp_regs.s_regs[idx] = (uint32_t)value;
}
else if ((dwarf_d0 <= reg_num) && (reg_num <= dwarf_d31))
{
if ((reg_num - dwarf_d0) < 16)
uint32_t idx = reg_num - dwarf_d0;
if (idx < 16)
{
m_vfp_regs.sd_regs[reg_num - dwarf_d0].d_reg = value;
m_vfp_regs.s_regs[idx * 2] = (uint32_t)value;
m_vfp_regs.s_regs[idx * 2 + 1] = (uint32_t)(value >> 32);
}
else
m_vfp_regs.d_regs[reg_num - dwarf_d16] = value;
m_vfp_regs.d_regs[idx - 16] = value;
}
else
return false;
Expand All @@ -110,14 +116,15 @@ EmulationStateARM::ReadPseudoRegisterValue (uint32_t reg_num, bool &success)
else if ((dwarf_s0 <= reg_num) && (reg_num <= dwarf_s31))
{
uint32_t idx = reg_num - dwarf_s0;
value = m_vfp_regs.sd_regs[idx / 2].s_reg[idx % 2];
value = m_vfp_regs.d_regs[idx];
}
else if ((dwarf_d0 <= reg_num) && (reg_num <= dwarf_d31))
{
if ((reg_num - dwarf_d0) < 16)
value = m_vfp_regs.sd_regs[reg_num - dwarf_d0].d_reg;
uint32_t idx = reg_num - dwarf_d0;
if (idx < 16)
value = (uint64_t)m_vfp_regs.s_regs[idx * 2] | ((uint64_t)m_vfp_regs.s_regs[idx * 2 + 1] >> 32);
else
value = m_vfp_regs.d_regs[reg_num - dwarf_d16];
value = m_vfp_regs.d_regs[idx - 16];
}
else
success = false;
Expand All @@ -131,8 +138,8 @@ EmulationStateARM::ClearPseudoRegisters ()
for (int i = 0; i < 17; ++i)
m_gpr[i] = 0;

for (int i = 0; i < 16; ++i)
m_vfp_regs.sd_regs[i].d_reg = 0;
for (int i = 0; i < 32; ++i)
m_vfp_regs.s_regs[i] = 0;

for (int i = 0; i < 16; ++i)
m_vfp_regs.d_regs[i] = 0;
Expand All @@ -145,23 +152,14 @@ EmulationStateARM::ClearPseudoMemory ()
}

bool
EmulationStateARM::StoreToPseudoAddress (lldb::addr_t p_address, uint64_t value, uint32_t size)
EmulationStateARM::StoreToPseudoAddress (lldb::addr_t p_address, uint32_t value)
{
if (size > 8)
return false;

if (size <= 4)
m_memory[p_address] = value;
else if (size == 8)
{
m_memory[p_address] = (value << 32) >> 32;
m_memory[p_address + 4] = value << 32;
}
m_memory[p_address] = value;
return true;
}

uint32_t
EmulationStateARM::ReadFromPseudoAddress (lldb::addr_t p_address, uint32_t size, bool &success)
EmulationStateARM::ReadFromPseudoAddress (lldb::addr_t p_address, bool &success)
{
std::map<lldb::addr_t,uint32_t>::iterator pos;
uint32_t ret_val = 0;
Expand Down Expand Up @@ -191,25 +189,31 @@ EmulationStateARM::ReadPseudoMemory (EmulateInstruction *instruction,
EmulationStateARM *pseudo_state = (EmulationStateARM *) baton;
if (length <= 4)
{
uint32_t value = pseudo_state->ReadFromPseudoAddress (addr, length, success);
uint32_t value = pseudo_state->ReadFromPseudoAddress (addr, success);
if (!success)
return 0;

if (endian::InlHostByteOrder() == lldb::eByteOrderBig)
value = llvm::ByteSwap_32 (value);
*((uint32_t *) dst) = value;
}
else if (length == 8)
{
uint32_t value1 = pseudo_state->ReadFromPseudoAddress (addr, 4, success);
uint32_t value1 = pseudo_state->ReadFromPseudoAddress (addr, success);
if (!success)
return 0;

uint32_t value2 = pseudo_state->ReadFromPseudoAddress (addr + 4, 4, success);
uint32_t value2 = pseudo_state->ReadFromPseudoAddress (addr + 4, success);
if (!success)
return 0;

uint64_t value64 = value2;
value64 = (value64 << 32) | value1;
*((uint64_t *) dst) = value64;
if (endian::InlHostByteOrder() == lldb::eByteOrderBig)
{
value1 = llvm::ByteSwap_32 (value1);
value2 = llvm::ByteSwap_32 (value2);
}
((uint32_t *) dst)[0] = value1;
((uint32_t *) dst)[1] = value2;
}
else
success = false;
Expand All @@ -231,13 +235,32 @@ EmulationStateARM::WritePseudoMemory (EmulateInstruction *instruction,
if (!baton)
return 0;

bool success;
EmulationStateARM *pseudo_state = (EmulationStateARM *) baton;
uint64_t value = *((const uint64_t *) dst);
success = pseudo_state->StoreToPseudoAddress (addr, value, length);
if (success)

if (length <= 4)
{
uint32_t value = *((const uint32_t *) dst);
if (endian::InlHostByteOrder() == lldb::eByteOrderBig)
value = llvm::ByteSwap_32 (value);

pseudo_state->StoreToPseudoAddress (addr, value);
return length;

}
else if (length == 8)
{
uint32_t value1 = ((const uint32_t *) dst)[0];
uint32_t value2 = ((const uint32_t *) dst)[1];
if (endian::InlHostByteOrder() == lldb::eByteOrderBig)
{
value1 = llvm::ByteSwap_32 (value1);
value2 = llvm::ByteSwap_32 (value2);
}

pseudo_state->StoreToPseudoAddress (addr, value1);
pseudo_state->StoreToPseudoAddress (addr + 4, value2);
return length;
}

return 0;
}

Expand Down Expand Up @@ -289,27 +312,16 @@ EmulationStateARM::CompareState (EmulationStateARM &other_state)
match = false;
}

for (int i = 0; match && i < 16; ++i)
for (int i = 0; match && i < 32; ++i)
{
if (m_vfp_regs.sd_regs[i].s_reg[0] != other_state.m_vfp_regs.sd_regs[i].s_reg[0])
match = false;

if (m_vfp_regs.sd_regs[i].s_reg[1] != other_state.m_vfp_regs.sd_regs[i].s_reg[1])
if (m_vfp_regs.s_regs[i] != other_state.m_vfp_regs.s_regs[i])
match = false;
}

for (int i = 0; match && i < 32; ++i)
for (int i = 0; match && i < 16; ++i)
{
if (i < 16)
{
if (m_vfp_regs.sd_regs[i].d_reg != other_state.m_vfp_regs.sd_regs[i].d_reg)
match = false;
}
else
{
if (m_vfp_regs.d_regs[i - 16] != other_state.m_vfp_regs.d_regs[i - 16])
match = false;
}
if (m_vfp_regs.d_regs[i] != other_state.m_vfp_regs.d_regs[i])
match = false;
}

return match;
Expand Down Expand Up @@ -355,7 +367,7 @@ EmulationStateARM::LoadStateFromDictionary (OptionValueDictionary *test_data)
if (value_sp.get() == NULL)
return false;
uint64_t value = value_sp->GetUInt64Value();
StoreToPseudoAddress (address, value, 4);
StoreToPseudoAddress (address, value);
address = address + 4;
}
}
Expand Down
10 changes: 3 additions & 7 deletions lldb/source/Plugins/Instruction/ARM/EmulationStateARM.h
View file
Expand Up @@ -30,10 +30,10 @@ class EmulationStateARM {
ReadPseudoRegisterValue (uint32_t reg_num, bool &success);

bool
StoreToPseudoAddress (lldb::addr_t p_address, uint64_t value, uint32_t size);
StoreToPseudoAddress (lldb::addr_t p_address, uint32_t value);

uint32_t
ReadFromPseudoAddress (lldb::addr_t p_address, uint32_t size, bool &success);
ReadFromPseudoAddress (lldb::addr_t p_address, bool &success);

void
ClearPseudoRegisters ();
Expand Down Expand Up @@ -82,11 +82,7 @@ class EmulationStateARM {
uint32_t m_gpr[17];
struct _sd_regs
{
union
{
uint32_t s_reg[2];
uint64_t d_reg;
} sd_regs[16]; // sregs 0 - 31 & dregs 0 - 15
uint32_t s_regs[32]; // sregs 0 - 31 & dregs 0 - 15

uint64_t d_regs[16]; // dregs 16-31

Expand Down

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