void
UnwindPlan::InsertRow (const UnwindPlan::RowSP &row_sp)
{
collection::iterator it = m_row_list.begin();
while (it != m_row_list.end()) {
RowSP row = *it;
if (row->GetOffset() >= row_sp->GetOffset())
break;
it++;
}
if (it == m_row_list.end() || (*it)->GetOffset() != row_sp->GetOffset())
m_row_list.insert(it, row_sp);
}
void UnwindPlan::AppendRow(const UnwindPlan::RowSP &row_sp) {
if (m_row_list.empty() ||
m_row_list.back()->GetOffset() != row_sp->GetOffset())
m_row_list.push_back(row_sp);
else
m_row_list.back() = row_sp;
}
bool
CompactUnwindInfo::CreateUnwindPlan_x86_64 (Target &target, FunctionInfo &function_info, UnwindPlan &unwind_plan, Address pc_or_function_start)
{
unwind_plan.SetSourceName ("compact unwind info");
unwind_plan.SetSourcedFromCompiler (eLazyBoolYes);
unwind_plan.SetUnwindPlanValidAtAllInstructions (eLazyBoolNo);
unwind_plan.SetRegisterKind (eRegisterKindEHFrame);
unwind_plan.SetLSDAAddress (function_info.lsda_address);
unwind_plan.SetPersonalityFunctionPtr (function_info.personality_ptr_address);
UnwindPlan::RowSP row (new UnwindPlan::Row);
const int wordsize = 8;
int mode = function_info.encoding & UNWIND_X86_64_MODE_MASK;
switch (mode)
{
case UNWIND_X86_64_MODE_RBP_FRAME:
{
row->GetCFAValue().SetIsRegisterPlusOffset (
translate_to_eh_frame_regnum_x86_64 (UNWIND_X86_64_REG_RBP),
2 * wordsize);
row->SetOffset (0);
row->SetRegisterLocationToAtCFAPlusOffset (x86_64_eh_regnum::rbp, wordsize * -2, true);
row->SetRegisterLocationToAtCFAPlusOffset (x86_64_eh_regnum::rip, wordsize * -1, true);
row->SetRegisterLocationToIsCFAPlusOffset (x86_64_eh_regnum::rsp, 0, true);
uint32_t saved_registers_offset = EXTRACT_BITS (function_info.encoding, UNWIND_X86_64_RBP_FRAME_OFFSET);
uint32_t saved_registers_locations = EXTRACT_BITS (function_info.encoding, UNWIND_X86_64_RBP_FRAME_REGISTERS);
saved_registers_offset += 2;
for (int i = 0; i < 5; i++)
{
uint32_t regnum = saved_registers_locations & 0x7;
switch (regnum)
{
case UNWIND_X86_64_REG_NONE:
break;
case UNWIND_X86_64_REG_RBX:
case UNWIND_X86_64_REG_R12:
case UNWIND_X86_64_REG_R13:
case UNWIND_X86_64_REG_R14:
case UNWIND_X86_64_REG_R15:
row->SetRegisterLocationToAtCFAPlusOffset (translate_to_eh_frame_regnum_x86_64 (regnum), wordsize * -saved_registers_offset, true);
break;
}
saved_registers_offset--;
saved_registers_locations >>= 3;
}
unwind_plan.AppendRow (row);
return true;
}
break;
case UNWIND_X86_64_MODE_STACK_IND:
{
// The clang in Xcode 6 is emitting incorrect compact unwind encodings for this
// style of unwind. It was fixed in llvm r217020.
// The clang in Xcode 7 has this fixed.
return false;
}
break;
case UNWIND_X86_64_MODE_STACK_IMMD:
{
uint32_t stack_size = EXTRACT_BITS (function_info.encoding, UNWIND_X86_64_FRAMELESS_STACK_SIZE);
uint32_t register_count = EXTRACT_BITS (function_info.encoding, UNWIND_X86_64_FRAMELESS_STACK_REG_COUNT);
uint32_t permutation = EXTRACT_BITS (function_info.encoding, UNWIND_X86_64_FRAMELESS_STACK_REG_PERMUTATION);
if (mode == UNWIND_X86_64_MODE_STACK_IND && function_info.valid_range_offset_start != 0)
{
uint32_t stack_adjust = EXTRACT_BITS (function_info.encoding, UNWIND_X86_64_FRAMELESS_STACK_ADJUST);
// offset into the function instructions; 0 == beginning of first instruction
uint32_t offset_to_subl_insn = EXTRACT_BITS (function_info.encoding, UNWIND_X86_64_FRAMELESS_STACK_SIZE);
SectionList *sl = m_objfile.GetSectionList ();
if (sl)
{
ProcessSP process_sp = target.GetProcessSP();
if (process_sp)
{
Address subl_payload_addr (function_info.valid_range_offset_start, sl);
subl_payload_addr.Slide (offset_to_subl_insn);
Error error;
uint64_t large_stack_size = process_sp->ReadUnsignedIntegerFromMemory (subl_payload_addr.GetLoadAddress (&target),
4, 0, error);
if (large_stack_size != 0 && error.Success ())
{
// Got the large stack frame size correctly - use it
stack_size = large_stack_size + (stack_adjust * wordsize);
}
else
{
return false;
}
}
else
{
return false;
}
}
else
{
return false;
}
}
int32_t offset = mode == UNWIND_X86_64_MODE_STACK_IND ? stack_size : stack_size * wordsize;
row->GetCFAValue().SetIsRegisterPlusOffset (x86_64_eh_regnum::rsp, offset);
row->SetOffset (0);
row->SetRegisterLocationToAtCFAPlusOffset (x86_64_eh_regnum::rip, wordsize * -1, true);
row->SetRegisterLocationToIsCFAPlusOffset (x86_64_eh_regnum::rsp, 0, true);
if (register_count > 0)
{
// We need to include (up to) 6 registers in 10 bits.
// That would be 18 bits if we just used 3 bits per reg to indicate
// the order they're saved on the stack.
//
// This is done with Lehmer code permutation, e.g. see
// http://stackoverflow.com/questions/1506078/fast-permutation-number-permutation-mapping-algorithms
int permunreg[6] = {0, 0, 0, 0, 0, 0};
// This decodes the variable-base number in the 10 bits
// and gives us the Lehmer code sequence which can then
// be decoded.
switch (register_count)
{
case 6:
permunreg[0] = permutation/120; // 120 == 5!
permutation -= (permunreg[0]*120);
permunreg[1] = permutation/24; // 24 == 4!
permutation -= (permunreg[1]*24);
permunreg[2] = permutation/6; // 6 == 3!
permutation -= (permunreg[2]*6);
permunreg[3] = permutation/2; // 2 == 2!
permutation -= (permunreg[3]*2);
permunreg[4] = permutation; // 1 == 1!
permunreg[5] = 0;
break;
case 5:
permunreg[0] = permutation/120;
permutation -= (permunreg[0]*120);
permunreg[1] = permutation/24;
permutation -= (permunreg[1]*24);
permunreg[2] = permutation/6;
permutation -= (permunreg[2]*6);
permunreg[3] = permutation/2;
permutation -= (permunreg[3]*2);
permunreg[4] = permutation;
break;
case 4:
permunreg[0] = permutation/60;
permutation -= (permunreg[0]*60);
permunreg[1] = permutation/12;
permutation -= (permunreg[1]*12);
permunreg[2] = permutation/3;
permutation -= (permunreg[2]*3);
permunreg[3] = permutation;
break;
case 3:
permunreg[0] = permutation/20;
permutation -= (permunreg[0]*20);
permunreg[1] = permutation/4;
permutation -= (permunreg[1]*4);
permunreg[2] = permutation;
break;
case 2:
permunreg[0] = permutation/5;
permutation -= (permunreg[0]*5);
permunreg[1] = permutation;
break;
case 1:
permunreg[0] = permutation;
break;
}
// Decode the Lehmer code for this permutation of
// the registers v. http://en.wikipedia.org/wiki/Lehmer_code
int registers[6] = { UNWIND_X86_64_REG_NONE, UNWIND_X86_64_REG_NONE, UNWIND_X86_64_REG_NONE, UNWIND_X86_64_REG_NONE, UNWIND_X86_64_REG_NONE, UNWIND_X86_64_REG_NONE };
bool used[7] = { false, false, false, false, false, false, false };
for (uint32_t i = 0; i < register_count; i++)
{
int renum = 0;
for (int j = 1; j < 7; j++)
{
if (used[j] == false)
{
if (renum == permunreg[i])
{
registers[i] = j;
used[j] = true;
break;
}
renum++;
}
}
}
uint32_t saved_registers_offset = 1;
saved_registers_offset++;
for (int i = (sizeof (registers) / sizeof (int)) - 1; i >= 0; i--)
{
switch (registers[i])
{
case UNWIND_X86_64_REG_NONE:
break;
case UNWIND_X86_64_REG_RBX:
case UNWIND_X86_64_REG_R12:
case UNWIND_X86_64_REG_R13:
case UNWIND_X86_64_REG_R14:
case UNWIND_X86_64_REG_R15:
case UNWIND_X86_64_REG_RBP:
row->SetRegisterLocationToAtCFAPlusOffset (translate_to_eh_frame_regnum_x86_64 (registers[i]), wordsize * -saved_registers_offset, true);
saved_registers_offset++;
break;
}
}
}
unwind_plan.AppendRow (row);
return true;
}
break;
case UNWIND_X86_64_MODE_DWARF:
{
return false;
}
break;
case 0:
{
return false;
}
break;
}
return false;
}