bool
DWARFCallFrameInfo::FDEToUnwindPlan (dw_offset_t dwarf_offset, Address startaddr, UnwindPlan& unwind_plan)
{
lldb::offset_t offset = dwarf_offset;
lldb::offset_t current_entry = offset;
if (m_section_sp.get() == nullptr || m_section_sp->IsEncrypted())
return false;
if (m_cfi_data_initialized == false)
GetCFIData();
uint32_t length = m_cfi_data.GetU32 (&offset);
dw_offset_t cie_offset;
bool is_64bit = (length == UINT32_MAX);
if (is_64bit) {
length = m_cfi_data.GetU64 (&offset);
cie_offset = m_cfi_data.GetU64 (&offset);
} else {
cie_offset = m_cfi_data.GetU32 (&offset);
}
assert (cie_offset != 0 && cie_offset != UINT32_MAX);
// Translate the CIE_id from the eh_frame format, which
// is relative to the FDE offset, into a __eh_frame section
// offset
if (m_is_eh_frame)
{
unwind_plan.SetSourceName ("eh_frame CFI");
cie_offset = current_entry + (is_64bit ? 12 : 4) - cie_offset;
unwind_plan.SetUnwindPlanValidAtAllInstructions (eLazyBoolNo);
}
else
{
unwind_plan.SetSourceName ("DWARF CFI");
// In theory the debug_frame info should be valid at all call sites
// ("asynchronous unwind info" as it is sometimes called) but in practice
// gcc et al all emit call frame info for the prologue and call sites, but
// not for the epilogue or all the other locations during the function reliably.
unwind_plan.SetUnwindPlanValidAtAllInstructions (eLazyBoolNo);
}
unwind_plan.SetSourcedFromCompiler (eLazyBoolYes);
const CIE *cie = GetCIE (cie_offset);
assert (cie != nullptr);
const dw_offset_t end_offset = current_entry + length + (is_64bit ? 12 : 4);
const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress();
const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS;
const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS;
lldb::addr_t range_base = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr);
lldb::addr_t range_len = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding & DW_EH_PE_MASK_ENCODING, pc_rel_addr, text_addr, data_addr);
AddressRange range (range_base, m_objfile.GetAddressByteSize(), m_objfile.GetSectionList());
range.SetByteSize (range_len);
addr_t lsda_data_file_address = LLDB_INVALID_ADDRESS;
if (cie->augmentation[0] == 'z')
{
uint32_t aug_data_len = (uint32_t)m_cfi_data.GetULEB128(&offset);
if (aug_data_len != 0 && cie->lsda_addr_encoding != DW_EH_PE_omit)
{
offset_t saved_offset = offset;
lsda_data_file_address = m_cfi_data.GetGNUEHPointer(&offset, cie->lsda_addr_encoding, pc_rel_addr, text_addr, data_addr);
if (offset - saved_offset != aug_data_len)
{
// There is more in the augmentation region than we know how to process;
// don't read anything.
lsda_data_file_address = LLDB_INVALID_ADDRESS;
}
offset = saved_offset;
}
offset += aug_data_len;
}
Address lsda_data;
Address personality_function_ptr;
if (lsda_data_file_address != LLDB_INVALID_ADDRESS && cie->personality_loc != LLDB_INVALID_ADDRESS)
{
m_objfile.GetModule()->ResolveFileAddress (lsda_data_file_address, lsda_data);
m_objfile.GetModule()->ResolveFileAddress (cie->personality_loc, personality_function_ptr);
}
if (lsda_data.IsValid() && personality_function_ptr.IsValid())
{
unwind_plan.SetLSDAAddress (lsda_data);
unwind_plan.SetPersonalityFunctionPtr (personality_function_ptr);
}
uint32_t code_align = cie->code_align;
int32_t data_align = cie->data_align;
unwind_plan.SetPlanValidAddressRange (range);
UnwindPlan::Row *cie_initial_row = new UnwindPlan::Row;
*cie_initial_row = cie->initial_row;
UnwindPlan::RowSP row(cie_initial_row);
unwind_plan.SetRegisterKind (m_reg_kind);
unwind_plan.SetReturnAddressRegister (cie->return_addr_reg_num);
std::vector<UnwindPlan::RowSP> stack;
UnwindPlan::Row::RegisterLocation reg_location;
while (m_cfi_data.ValidOffset(offset) && offset < end_offset)
{
uint8_t inst = m_cfi_data.GetU8(&offset);
uint8_t primary_opcode = inst & 0xC0;
uint8_t extended_opcode = inst & 0x3F;
if (!HandleCommonDwarfOpcode(primary_opcode, extended_opcode, data_align, offset, *row))
{
if (primary_opcode)
{
switch (primary_opcode)
{
case DW_CFA_advance_loc : // (Row Creation Instruction)
{ // 0x40 - high 2 bits are 0x1, lower 6 bits are delta
// takes a single argument that represents a constant delta. The
// required action is to create a new table row with a location
// value that is computed by taking the current entry's location
// value and adding (delta * code_align). All other
// values in the new row are initially identical to the current row.
unwind_plan.AppendRow(row);
UnwindPlan::Row *newrow = new UnwindPlan::Row;
*newrow = *row.get();
row.reset (newrow);
row->SlideOffset(extended_opcode * code_align);
break;
}
case DW_CFA_restore :
{ // 0xC0 - high 2 bits are 0x3, lower 6 bits are register
// takes a single argument that represents a register number. The
// required action is to change the rule for the indicated register
// to the rule assigned it by the initial_instructions in the CIE.
uint32_t reg_num = extended_opcode;
// We only keep enough register locations around to
// unwind what is in our thread, and these are organized
// by the register index in that state, so we need to convert our
// GCC register number from the EH frame info, to a register index
if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, reg_location))
row->SetRegisterInfo (reg_num, reg_location);
break;
}
}
}
else
{
switch (extended_opcode)
{
case DW_CFA_set_loc : // 0x1 (Row Creation Instruction)
{
// DW_CFA_set_loc takes a single argument that represents an address.
// The required action is to create a new table row using the
// specified address as the location. All other values in the new row
// are initially identical to the current row. The new location value
// should always be greater than the current one.
unwind_plan.AppendRow(row);
UnwindPlan::Row *newrow = new UnwindPlan::Row;
*newrow = *row.get();
row.reset (newrow);
row->SetOffset(m_cfi_data.GetPointer(&offset) - startaddr.GetFileAddress());
break;
}
case DW_CFA_advance_loc1 : // 0x2 (Row Creation Instruction)
{
// takes a single uword argument that represents a constant delta.
// This instruction is identical to DW_CFA_advance_loc except for the
// encoding and size of the delta argument.
unwind_plan.AppendRow(row);
UnwindPlan::Row *newrow = new UnwindPlan::Row;
*newrow = *row.get();
row.reset (newrow);
row->SlideOffset (m_cfi_data.GetU8(&offset) * code_align);
break;
}
case DW_CFA_advance_loc2 : // 0x3 (Row Creation Instruction)
{
// takes a single uword argument that represents a constant delta.
// This instruction is identical to DW_CFA_advance_loc except for the
// encoding and size of the delta argument.
unwind_plan.AppendRow(row);
UnwindPlan::Row *newrow = new UnwindPlan::Row;
*newrow = *row.get();
row.reset (newrow);
row->SlideOffset (m_cfi_data.GetU16(&offset) * code_align);
break;
}
case DW_CFA_advance_loc4 : // 0x4 (Row Creation Instruction)
{
// takes a single uword argument that represents a constant delta.
// This instruction is identical to DW_CFA_advance_loc except for the
// encoding and size of the delta argument.
unwind_plan.AppendRow(row);
UnwindPlan::Row *newrow = new UnwindPlan::Row;
*newrow = *row.get();
row.reset (newrow);
row->SlideOffset (m_cfi_data.GetU32(&offset) * code_align);
break;
}
case DW_CFA_restore_extended : // 0x6
{
// takes a single unsigned LEB128 argument that represents a register
// number. This instruction is identical to DW_CFA_restore except for
// the encoding and size of the register argument.
uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, reg_location))
row->SetRegisterInfo (reg_num, reg_location);
break;
}
case DW_CFA_remember_state : // 0xA
{
// These instructions define a stack of information. Encountering the
// DW_CFA_remember_state instruction means to save the rules for every
// register on the current row on the stack. Encountering the
// DW_CFA_restore_state instruction means to pop the set of rules off
// the stack and place them in the current row. (This operation is
// useful for compilers that move epilogue code into the body of a
// function.)
stack.push_back (row);
UnwindPlan::Row *newrow = new UnwindPlan::Row;
*newrow = *row.get();
row.reset (newrow);
break;
}
case DW_CFA_restore_state : // 0xB
{
// These instructions define a stack of information. Encountering the
// DW_CFA_remember_state instruction means to save the rules for every
// register on the current row on the stack. Encountering the
// DW_CFA_restore_state instruction means to pop the set of rules off
// the stack and place them in the current row. (This operation is
// useful for compilers that move epilogue code into the body of a
// function.)
lldb::addr_t offset = row->GetOffset ();
row = stack.back ();
stack.pop_back ();
row->SetOffset (offset);
break;
}
case DW_CFA_val_offset : // 0x14
case DW_CFA_val_offset_sf : // 0x15
default:
break;
}
}
}
}
unwind_plan.AppendRow(row);
return true;
}
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;
}
bool
DWARFCallFrameInfo::FDEToUnwindPlan (dw_offset_t dwarf_offset, Address startaddr, UnwindPlan& unwind_plan)
{
lldb::offset_t offset = dwarf_offset;
lldb::offset_t current_entry = offset;
if (m_section_sp.get() == nullptr || m_section_sp->IsEncrypted())
return false;
if (m_cfi_data_initialized == false)
GetCFIData();
uint32_t length = m_cfi_data.GetU32 (&offset);
dw_offset_t cie_offset;
bool is_64bit = (length == UINT32_MAX);
if (is_64bit) {
length = m_cfi_data.GetU64 (&offset);
cie_offset = m_cfi_data.GetU64 (&offset);
} else {
cie_offset = m_cfi_data.GetU32 (&offset);
}
assert (cie_offset != 0 && cie_offset != UINT32_MAX);
// Translate the CIE_id from the eh_frame format, which
// is relative to the FDE offset, into a __eh_frame section
// offset
if (m_is_eh_frame)
{
unwind_plan.SetSourceName ("eh_frame CFI");
cie_offset = current_entry + (is_64bit ? 12 : 4) - cie_offset;
unwind_plan.SetUnwindPlanValidAtAllInstructions (eLazyBoolNo);
}
else
{
unwind_plan.SetSourceName ("DWARF CFI");
// In theory the debug_frame info should be valid at all call sites
// ("asynchronous unwind info" as it is sometimes called) but in practice
// gcc et al all emit call frame info for the prologue and call sites, but
// not for the epilogue or all the other locations during the function reliably.
unwind_plan.SetUnwindPlanValidAtAllInstructions (eLazyBoolNo);
}
unwind_plan.SetSourcedFromCompiler (eLazyBoolYes);
const CIE *cie = GetCIE (cie_offset);
assert (cie != nullptr);
const dw_offset_t end_offset = current_entry + length + (is_64bit ? 12 : 4);
const lldb::addr_t pc_rel_addr = m_section_sp->GetFileAddress();
const lldb::addr_t text_addr = LLDB_INVALID_ADDRESS;
const lldb::addr_t data_addr = LLDB_INVALID_ADDRESS;
lldb::addr_t range_base = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding, pc_rel_addr, text_addr, data_addr);
lldb::addr_t range_len = m_cfi_data.GetGNUEHPointer(&offset, cie->ptr_encoding & DW_EH_PE_MASK_ENCODING, pc_rel_addr, text_addr, data_addr);
AddressRange range (range_base, m_objfile.GetAddressByteSize(), m_objfile.GetSectionList());
range.SetByteSize (range_len);
addr_t lsda_data_file_address = LLDB_INVALID_ADDRESS;
if (cie->augmentation[0] == 'z')
{
uint32_t aug_data_len = (uint32_t)m_cfi_data.GetULEB128(&offset);
if (aug_data_len != 0 && cie->lsda_addr_encoding != DW_EH_PE_omit)
{
offset_t saved_offset = offset;
lsda_data_file_address = m_cfi_data.GetGNUEHPointer(&offset, cie->lsda_addr_encoding, pc_rel_addr, text_addr, data_addr);
if (offset - saved_offset != aug_data_len)
{
// There is more in the augmentation region than we know how to process;
// don't read anything.
lsda_data_file_address = LLDB_INVALID_ADDRESS;
}
offset = saved_offset;
}
offset += aug_data_len;
}
Address lsda_data;
Address personality_function_ptr;
if (lsda_data_file_address != LLDB_INVALID_ADDRESS && cie->personality_loc != LLDB_INVALID_ADDRESS)
{
m_objfile.GetModule()->ResolveFileAddress (lsda_data_file_address, lsda_data);
m_objfile.GetModule()->ResolveFileAddress (cie->personality_loc, personality_function_ptr);
}
if (lsda_data.IsValid() && personality_function_ptr.IsValid())
{
unwind_plan.SetLSDAAddress (lsda_data);
unwind_plan.SetPersonalityFunctionPtr (personality_function_ptr);
}
uint32_t reg_num = 0;
int32_t op_offset = 0;
uint32_t code_align = cie->code_align;
int32_t data_align = cie->data_align;
unwind_plan.SetPlanValidAddressRange (range);
UnwindPlan::Row *cie_initial_row = new UnwindPlan::Row;
*cie_initial_row = cie->initial_row;
UnwindPlan::RowSP row(cie_initial_row);
unwind_plan.SetRegisterKind (m_reg_kind);
unwind_plan.SetReturnAddressRegister (cie->return_addr_reg_num);
std::vector<UnwindPlan::RowSP> stack;
UnwindPlan::Row::RegisterLocation reg_location;
while (m_cfi_data.ValidOffset(offset) && offset < end_offset)
{
uint8_t inst = m_cfi_data.GetU8(&offset);
uint8_t primary_opcode = inst & 0xC0;
uint8_t extended_opcode = inst & 0x3F;
if (primary_opcode)
{
switch (primary_opcode)
{
case DW_CFA_advance_loc : // (Row Creation Instruction)
{ // 0x40 - high 2 bits are 0x1, lower 6 bits are delta
// takes a single argument that represents a constant delta. The
// required action is to create a new table row with a location
// value that is computed by taking the current entry's location
// value and adding (delta * code_align). All other
// values in the new row are initially identical to the current row.
unwind_plan.AppendRow(row);
UnwindPlan::Row *newrow = new UnwindPlan::Row;
*newrow = *row.get();
row.reset (newrow);
row->SlideOffset(extended_opcode * code_align);
}
break;
case DW_CFA_offset :
{ // 0x80 - high 2 bits are 0x2, lower 6 bits are register
// takes two arguments: an unsigned LEB128 constant representing a
// factored offset and a register number. The required action is to
// change the rule for the register indicated by the register number
// to be an offset(N) rule with a value of
// (N = factored offset * data_align).
reg_num = extended_opcode;
op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align;
reg_location.SetAtCFAPlusOffset(op_offset);
row->SetRegisterInfo (reg_num, reg_location);
}
break;
case DW_CFA_restore :
{ // 0xC0 - high 2 bits are 0x3, lower 6 bits are register
// takes a single argument that represents a register number. The
// required action is to change the rule for the indicated register
// to the rule assigned it by the initial_instructions in the CIE.
reg_num = extended_opcode;
// We only keep enough register locations around to
// unwind what is in our thread, and these are organized
// by the register index in that state, so we need to convert our
// GCC register number from the EH frame info, to a register index
if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, reg_location))
row->SetRegisterInfo (reg_num, reg_location);
}
break;
}
}
else
{
switch (extended_opcode)
{
case DW_CFA_nop : // 0x0
break;
case DW_CFA_set_loc : // 0x1 (Row Creation Instruction)
{
// DW_CFA_set_loc takes a single argument that represents an address.
// The required action is to create a new table row using the
// specified address as the location. All other values in the new row
// are initially identical to the current row. The new location value
// should always be greater than the current one.
unwind_plan.AppendRow(row);
UnwindPlan::Row *newrow = new UnwindPlan::Row;
*newrow = *row.get();
row.reset (newrow);
row->SetOffset(m_cfi_data.GetPointer(&offset) - startaddr.GetFileAddress());
}
break;
case DW_CFA_advance_loc1 : // 0x2 (Row Creation Instruction)
{
// takes a single uword argument that represents a constant delta.
// This instruction is identical to DW_CFA_advance_loc except for the
// encoding and size of the delta argument.
unwind_plan.AppendRow(row);
UnwindPlan::Row *newrow = new UnwindPlan::Row;
*newrow = *row.get();
row.reset (newrow);
row->SlideOffset (m_cfi_data.GetU8(&offset) * code_align);
}
break;
case DW_CFA_advance_loc2 : // 0x3 (Row Creation Instruction)
{
// takes a single uword argument that represents a constant delta.
// This instruction is identical to DW_CFA_advance_loc except for the
// encoding and size of the delta argument.
unwind_plan.AppendRow(row);
UnwindPlan::Row *newrow = new UnwindPlan::Row;
*newrow = *row.get();
row.reset (newrow);
row->SlideOffset (m_cfi_data.GetU16(&offset) * code_align);
}
break;
case DW_CFA_advance_loc4 : // 0x4 (Row Creation Instruction)
{
// takes a single uword argument that represents a constant delta.
// This instruction is identical to DW_CFA_advance_loc except for the
// encoding and size of the delta argument.
unwind_plan.AppendRow(row);
UnwindPlan::Row *newrow = new UnwindPlan::Row;
*newrow = *row.get();
row.reset (newrow);
row->SlideOffset (m_cfi_data.GetU32(&offset) * code_align);
}
break;
case DW_CFA_offset_extended : // 0x5
{
// takes two unsigned LEB128 arguments representing a register number
// and a factored offset. This instruction is identical to DW_CFA_offset
// except for the encoding and size of the register argument.
reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
op_offset = (int32_t)m_cfi_data.GetULEB128(&offset) * data_align;
reg_location.SetAtCFAPlusOffset(op_offset);
row->SetRegisterInfo (reg_num, reg_location);
}
break;
case DW_CFA_restore_extended : // 0x6
{
// takes a single unsigned LEB128 argument that represents a register
// number. This instruction is identical to DW_CFA_restore except for
// the encoding and size of the register argument.
reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
if (unwind_plan.IsValidRowIndex(0) && unwind_plan.GetRowAtIndex(0)->GetRegisterInfo(reg_num, reg_location))
row->SetRegisterInfo (reg_num, reg_location);
}
break;
case DW_CFA_undefined : // 0x7
{
// takes a single unsigned LEB128 argument that represents a register
// number. The required action is to set the rule for the specified
// register to undefined.
reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
reg_location.SetUndefined();
row->SetRegisterInfo (reg_num, reg_location);
}
break;
case DW_CFA_same_value : // 0x8
{
// takes a single unsigned LEB128 argument that represents a register
// number. The required action is to set the rule for the specified
// register to same value.
reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
reg_location.SetSame();
row->SetRegisterInfo (reg_num, reg_location);
}
break;
case DW_CFA_register : // 0x9
{
// takes two unsigned LEB128 arguments representing register numbers.
// The required action is to set the rule for the first register to be
// the second register.
reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
uint32_t other_reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
reg_location.SetInRegister(other_reg_num);
row->SetRegisterInfo (reg_num, reg_location);
}
break;
case DW_CFA_remember_state : // 0xA
{
// These instructions define a stack of information. Encountering the
// DW_CFA_remember_state instruction means to save the rules for every
// register on the current row on the stack. Encountering the
// DW_CFA_restore_state instruction means to pop the set of rules off
// the stack and place them in the current row. (This operation is
// useful for compilers that move epilogue code into the body of a
// function.)
stack.push_back (row);
UnwindPlan::Row *newrow = new UnwindPlan::Row;
*newrow = *row.get();
row.reset (newrow);
}
break;
case DW_CFA_restore_state : // 0xB
// These instructions define a stack of information. Encountering the
// DW_CFA_remember_state instruction means to save the rules for every
// register on the current row on the stack. Encountering the
// DW_CFA_restore_state instruction means to pop the set of rules off
// the stack and place them in the current row. (This operation is
// useful for compilers that move epilogue code into the body of a
// function.)
{
row = stack.back ();
stack.pop_back ();
}
break;
case DW_CFA_def_cfa : // 0xC (CFA Definition Instruction)
{
// Takes two unsigned LEB128 operands representing a register
// number and a (non-factored) offset. The required action
// is to define the current CFA rule to use the provided
// register and offset.
reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
op_offset = (int32_t)m_cfi_data.GetULEB128(&offset);
row->SetCFARegister (reg_num);
row->SetCFAOffset (op_offset);
}
break;
case DW_CFA_def_cfa_register : // 0xD (CFA Definition Instruction)
{
// takes a single unsigned LEB128 argument representing a register
// number. The required action is to define the current CFA rule to
// use the provided register (but to keep the old offset).
reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
row->SetCFARegister (reg_num);
}
break;
case DW_CFA_def_cfa_offset : // 0xE (CFA Definition Instruction)
{
// Takes a single unsigned LEB128 operand representing a
// (non-factored) offset. The required action is to define
// the current CFA rule to use the provided offset (but
// to keep the old register).
op_offset = (int32_t)m_cfi_data.GetULEB128(&offset);
row->SetCFAOffset (op_offset);
}
break;
case DW_CFA_def_cfa_expression : // 0xF (CFA Definition Instruction)
{
size_t block_len = (size_t)m_cfi_data.GetULEB128(&offset);
offset += (uint32_t)block_len;
}
break;
case DW_CFA_expression : // 0x10
{
// Takes two operands: an unsigned LEB128 value representing
// a register number, and a DW_FORM_block value representing a DWARF
// expression. The required action is to change the rule for the
// register indicated by the register number to be an expression(E)
// rule where E is the DWARF expression. That is, the DWARF
// expression computes the address. The value of the CFA is
// pushed on the DWARF evaluation stack prior to execution of
// the DWARF expression.
reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset);
const uint8_t *block_data = (uint8_t *)m_cfi_data.GetData(&offset, block_len);
reg_location.SetAtDWARFExpression(block_data, block_len);
row->SetRegisterInfo (reg_num, reg_location);
}
break;
case DW_CFA_offset_extended_sf : // 0x11
{
// takes two operands: an unsigned LEB128 value representing a
// register number and a signed LEB128 factored offset. This
// instruction is identical to DW_CFA_offset_extended except
//that the second operand is signed and factored.
reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align;
reg_location.SetAtCFAPlusOffset(op_offset);
row->SetRegisterInfo (reg_num, reg_location);
}
break;
case DW_CFA_def_cfa_sf : // 0x12 (CFA Definition Instruction)
{
// Takes two operands: an unsigned LEB128 value representing
// a register number and a signed LEB128 factored offset.
// This instruction is identical to DW_CFA_def_cfa except
// that the second operand is signed and factored.
reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align;
row->SetCFARegister (reg_num);
row->SetCFAOffset (op_offset);
}
break;
case DW_CFA_def_cfa_offset_sf : // 0x13 (CFA Definition Instruction)
{
// takes a signed LEB128 operand representing a factored
// offset. This instruction is identical to DW_CFA_def_cfa_offset
// except that the operand is signed and factored.
op_offset = (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align;
row->SetCFAOffset (op_offset);
}
break;
case DW_CFA_val_expression : // 0x16
{
// takes two operands: an unsigned LEB128 value representing a register
// number, and a DW_FORM_block value representing a DWARF expression.
// The required action is to change the rule for the register indicated
// by the register number to be a val_expression(E) rule where E is the
// DWARF expression. That is, the DWARF expression computes the value of
// the given register. The value of the CFA is pushed on the DWARF
// evaluation stack prior to execution of the DWARF expression.
reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
uint32_t block_len = (uint32_t)m_cfi_data.GetULEB128(&offset);
const uint8_t* block_data = (uint8_t*)m_cfi_data.GetData(&offset, block_len);
//#if defined(__i386__) || defined(__x86_64__)
// // The EH frame info for EIP and RIP contains code that looks for traps to
// // be a specific type and increments the PC.
// // For i386:
// // DW_CFA_val_expression where:
// // eip = DW_OP_breg6(+28), DW_OP_deref, DW_OP_dup, DW_OP_plus_uconst(0x34),
// // DW_OP_deref, DW_OP_swap, DW_OP_plus_uconst(0), DW_OP_deref,
// // DW_OP_dup, DW_OP_lit3, DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne,
// // DW_OP_and, DW_OP_plus
// // This basically does a:
// // eip = ucontenxt.mcontext32->gpr.eip;
// // if (ucontenxt.mcontext32->exc.trapno != 3 && ucontenxt.mcontext32->exc.trapno != 4)
// // eip++;
// //
// // For x86_64:
// // DW_CFA_val_expression where:
// // rip = DW_OP_breg3(+48), DW_OP_deref, DW_OP_dup, DW_OP_plus_uconst(0x90), DW_OP_deref,
// // DW_OP_swap, DW_OP_plus_uconst(0), DW_OP_deref_size(4), DW_OP_dup, DW_OP_lit3,
// // DW_OP_ne, DW_OP_swap, DW_OP_lit4, DW_OP_ne, DW_OP_and, DW_OP_plus
// // This basically does a:
// // rip = ucontenxt.mcontext64->gpr.rip;
// // if (ucontenxt.mcontext64->exc.trapno != 3 && ucontenxt.mcontext64->exc.trapno != 4)
// // rip++;
// // The trap comparisons and increments are not needed as it hoses up the unwound PC which
// // is expected to point at least past the instruction that causes the fault/trap. So we
// // take it out by trimming the expression right at the first "DW_OP_swap" opcodes
// if (block_data != NULL && thread->GetPCRegNum(Thread::GCC) == reg_num)
// {
// if (thread->Is64Bit())
// {
// if (block_len > 9 && block_data[8] == DW_OP_swap && block_data[9] == DW_OP_plus_uconst)
// block_len = 8;
// }
// else
// {
// if (block_len > 8 && block_data[7] == DW_OP_swap && block_data[8] == DW_OP_plus_uconst)
// block_len = 7;
// }
// }
//#endif
reg_location.SetIsDWARFExpression(block_data, block_len);
row->SetRegisterInfo (reg_num, reg_location);
}
break;
case DW_CFA_val_offset : // 0x14
case DW_CFA_val_offset_sf : // 0x15
default:
break;
}
}
}
unwind_plan.AppendRow(row);
return true;
}
