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lldb_private::DWARFExpression Class Reference

"lldb/Expression/DWARFExpression.h" Encapsulates a DWARF location expression and interprets it. More...

#include <DWARFExpression.h>

Collaboration diagram for lldb_private::DWARFExpression:
Collaboration graph

Public Member Functions

 DWARFExpression ()
 DWARFExpression (const DataExtractor &data)
virtual ~DWARFExpression ()
bool IsValid () const
 Return true if the location expression contains data.
lldb::addr_t GetLocation_DW_OP_addr (const DWARFUnit *dwarf_cu, uint32_t op_addr_idx, bool &error) const
 If a location is not a location list, return true if the location contains a DW_OP_addr () opcode in the stream that matches file_addr.
bool Update_DW_OP_addr (const DWARFUnit *dwarf_cu, lldb::addr_t file_addr)
void UpdateValue (uint64_t const_value, lldb::offset_t const_value_byte_size, uint8_t addr_byte_size)
bool ContainsThreadLocalStorage (const DWARFUnit *dwarf_cu) const
bool LinkThreadLocalStorage (const DWARFUnit *dwarf_cu, std::function< lldb::addr_t(lldb::addr_t file_addr)> const &link_address_callback)
lldb::RegisterKind GetRegisterKind () const
 Return the call-frame-info style register kind.
void SetRegisterKind (lldb::RegisterKind reg_kind)
 Set the call-frame-info style register kind.
bool GetExpressionData (DataExtractor &data) const
void DumpLocation (Stream *s, lldb::DescriptionLevel level, ABI *abi) const
bool MatchesOperand (StackFrame &frame, const Instruction::Operand &op) const

Static Public Member Functions

static bool Evaluate (ExecutionContext *exe_ctx, RegisterContext *reg_ctx, lldb::ModuleSP module_sp, const DataExtractor &opcodes, const DWARFUnit *dwarf_cu, const lldb::RegisterKind reg_set, const Value *initial_value_ptr, const Value *object_address_ptr, Value &result, Status *error_ptr)
 Evaluate a DWARF location expression in a particular context.
static bool ParseDWARFLocationList (const DWARFUnit *dwarf_cu, const DataExtractor &data, DWARFExpressionList *loc_list)

Private Attributes

DataExtractor m_data
 A data extractor capable of reading opcode bytes.
lldb::RegisterKind m_reg_kind = lldb::eRegisterKindDWARF
 One of the defines that starts with LLDB_REGKIND_.

Detailed Description

"lldb/Expression/DWARFExpression.h" Encapsulates a DWARF location expression and interprets it.

DWARF location expressions are used in two ways by LLDB. The first use is to find entities specified in the debug information, since their locations are specified in precisely this language. The second is to interpret expressions without having to run the target in cases where the overhead from copying JIT-compiled code into the target is too high or where the target cannot be run. This class encapsulates a single DWARF location expression or a location list and interprets it.

Definition at line 36 of file DWARFExpression.h.

Constructor & Destructor Documentation

◆ DWARFExpression() [1/2]

DWARFExpression::DWARFExpression ( )

Definition at line 50 of file DWARFExpression.cpp.

Referenced by ParseDWARFLocationList().

◆ DWARFExpression() [2/2]

DWARFExpression::DWARFExpression ( const DataExtractor data)


[in]dataA data extractor configured to read the DWARF location expression's bytecode.

Definition at line 52 of file DWARFExpression.cpp.

◆ ~DWARFExpression()

DWARFExpression::~DWARFExpression ( )


Member Function Documentation

◆ ContainsThreadLocalStorage()

bool DWARFExpression::ContainsThreadLocalStorage ( const DWARFUnit dwarf_cu) const

◆ DumpLocation()

void DWARFExpression::DumpLocation ( Stream s,
lldb::DescriptionLevel  level,
ABI abi 
) const

◆ Evaluate()

bool DWARFExpression::Evaluate ( ExecutionContext exe_ctx,
RegisterContext reg_ctx,
lldb::ModuleSP  module_sp,
const DataExtractor opcodes,
const DWARFUnit dwarf_cu,
const lldb::RegisterKind  reg_set,
const Value initial_value_ptr,
const Value object_address_ptr,
Value result,
Status error_ptr 

Evaluate a DWARF location expression in a particular context.

[in]exe_ctxThe execution context in which to evaluate the location expression. The location expression may access the target's memory, especially if it comes from the expression parser.
[in]opcode_ctxThe module which defined the expression.
[in]opcodesThis is a static method so the opcodes need to be provided explicitly.
[in]reg_ctxAn optional parameter which provides a RegisterContext for use when evaluating the expression (i.e. for fetching register values). Normally this will come from the ExecutionContext's StackFrame but in the case where an expression needs to be evaluated while building the stack frame list, this short-cut is available.
[in]reg_setThe call-frame-info style register kind.
[in]initial_value_ptrA value to put on top of the interpreter stack before evaluating the expression, if the expression is parametrized. Can be NULL.
[in]resultA value into which the result of evaluating the expression is to be placed.
[in]error_ptrIf non-NULL, used to report errors in expression evaluation.
True on success; false otherwise. If error_ptr is non-NULL, details of the failure are provided through it.

Insertion point for evaluating multi-piece expression.

Definition at line 856 of file DWARFExpression.cpp.

References lldb_private::Value::AppendDataToHostBuffer(), lldb_private::Value::ClearContext(), DerefSizeExtractDataHelper(), lldb_private::DW_OP_value_to_name(), lldb_private::ArchSpec::eCore_wasm32, error(), Evaluate_DW_OP_entry_value(), lldb_private::Expressions, lldb_private::Scalar::ExtractBitfield(), lldb_private::Value::FileAddress, lldb_private::Process::GetABI(), lldb_private::DataExtractor::GetAddress(), lldb_private::DataExtractor::GetAddressByteSize(), lldb_private::Target::GetArchitecture(), DWARFBaseDIE::GetAttributeValueAsUnsigned(), lldb_private::Value::GetBuffer(), lldb_private::Process::GetByteOrder(), lldb_private::ObjectFile::GetByteOrder(), lldb_private::DataExtractor::GetByteSize(), lldb_private::Scalar::GetByteSize(), lldb_private::DataBufferHeap::GetByteSize(), lldb_private::StackID::GetCallFrameAddress(), lldb_private::ArchSpec::GetCore(), lldb_private::StreamString::GetData(), lldb_private::DataExtractor::GetData(), lldb_private::StackFrame::GetFrameBaseValue(), lldb_private::ExecutionContext::GetFramePtr(), lldb_private::GetLog(), DWARFUnit::GetOffset(), lldb_private::ExecutionContext::GetProcessPtr(), lldb_private::StackFrame::GetRegisterContext(), lldb_private::Value::GetScalar(), lldb_private::DataExtractor::GetSLEB128(), lldb_private::StackFrame::GetStackID(), DWARFUnit::GetSymbolFileDWARF(), lldb_private::ExecutionContext::GetTargetPtr(), lldb_private::ExecutionContext::GetTargetRef(), lldb_private::Thread::GetThreadLocalData(), lldb_private::ExecutionContext::GetThreadPtr(), lldb_private::DataExtractor::GetU16(), lldb_private::DataExtractor::GetU32(), lldb_private::DataExtractor::GetU64(), lldb_private::DataExtractor::GetU8(), lldb_private::DataExtractor::GetULEB128(), lldb_private::Value::GetValueType(), lldb_private::Log::GetVerbose(), lldb_private::Value::HostAddress, lldb_private::Value::Invalid, lldb_private::Address::IsSectionOffset(), lldb_private::Scalar::IsZero(), LLDB_ERRORF, LLDB_INVALID_ADDRESS, LLDB_LOG, LLDB_LOGF, lldb_private::Value::LoadAddress, lldb_private::Memory, SymbolFileDWARF::ParseVendorDWARFOpcode(), lldb_private::Stream::Printf(), DWARFUnit::ReadAddressFromDebugAddrSection(), lldb_private::Target::ReadMemory(), lldb_private::Process::ReadMemory(), lldb_private::Process::ReadPointerFromMemory(), ReadRegisterValueAsScalar(), lldb_private::Value::ResizeData(), ResolveLoadAddress(), lldb_private::Value::ResolveValue(), lldb_private::Value::Scalar, lldb_private::Status::SetErrorString(), lldb_private::Status::SetErrorStringWithFormat(), lldb_private::Status::SetErrorStringWithFormatv(), lldb_private::Scalar::TruncOrExtendTo(), lldb_private::Scalar::UInt128(), lldb_private::Scalar::ULongLong(), and lldb_private::DataExtractor::ValidOffset().

Referenced by lldb_private::DWARFExpressionList::Evaluate(), and DWARFASTParserClang::ParseInheritance().

◆ GetExpressionData()

bool lldb_private::DWARFExpression::GetExpressionData ( DataExtractor data) const

◆ GetLocation_DW_OP_addr()

lldb::addr_t DWARFExpression::GetLocation_DW_OP_addr ( const DWARFUnit dwarf_cu,
uint32_t  op_addr_idx,
bool &  error 
) const

If a location is not a location list, return true if the location contains a DW_OP_addr () opcode in the stream that matches file_addr.

If file_addr is LLDB_INVALID_ADDRESS, the this function will return true if the variable there is any DW_OP_addr in a location that (yet still is NOT a location list). This helps us detect if a variable is a global or static variable since there is no other indication from DWARF debug info.

[in]dwarf_cuThe dwarf unit this expression belongs to.
[in]op_addr_idxThe DW_OP_addr index to retrieve in case there is more than one DW_OP_addr opcode in the location byte stream.
[out]errorIf the location stream contains unknown DW_OP opcodes or the data is missing, error will be set to true.
LLDB_INVALID_ADDRESS if the location doesn't contain a DW_OP_addr for op_addr_idx, otherwise a valid file address

Definition at line 357 of file DWARFExpression.cpp.

References error(), lldb_private::DataExtractor::GetAddress(), GetOpcodeDataSize(), lldb_private::DataExtractor::GetU8(), lldb_private::DataExtractor::GetULEB128(), LLDB_INVALID_ADDRESS, LLDB_INVALID_OFFSET, m_data, DWARFUnit::ReadAddressFromDebugAddrSection(), and lldb_private::DataExtractor::ValidOffset().

Referenced by SymbolFileDWARF::ParseVariableDIE().

◆ GetRegisterKind()

RegisterKind DWARFExpression::GetRegisterKind ( ) const

Return the call-frame-info style register kind.

Definition at line 90 of file DWARFExpression.cpp.

References m_reg_kind.

Referenced by lldb_private::DWARFExpressionList::Evaluate().

◆ IsValid()

bool DWARFExpression::IsValid ( ) const

Return true if the location expression contains data.

Definition at line 57 of file DWARFExpression.cpp.

References lldb_private::DataExtractor::GetByteSize(), and m_data.

◆ LinkThreadLocalStorage()

bool DWARFExpression::LinkThreadLocalStorage ( const DWARFUnit dwarf_cu,
std::function< lldb::addr_t(lldb::addr_t file_addr)> const &  link_address_callback 

◆ MatchesOperand()

bool DWARFExpression::MatchesOperand ( StackFrame frame,
const Instruction::Operand op 
) const

◆ ParseDWARFLocationList()

bool DWARFExpression::ParseDWARFLocationList ( const DWARFUnit dwarf_cu,
const DataExtractor data,
DWARFExpressionList loc_list 

◆ SetRegisterKind()

void DWARFExpression::SetRegisterKind ( lldb::RegisterKind  reg_kind)

Set the call-frame-info style register kind.

[in]reg_kindThe register kind.

Definition at line 92 of file DWARFExpression.cpp.

References m_reg_kind.

Referenced by ConvertPDBLocationToDWARFExpression(), MakeLocationExpressionInternal(), lldb_private::RegisterContextUnwind::ReadFrameAddress(), and lldb_private::RegisterContextUnwind::SavedLocationForRegister().

◆ Update_DW_OP_addr()

bool DWARFExpression::Update_DW_OP_addr ( const DWARFUnit dwarf_cu,
lldb::addr_t  file_addr 

◆ UpdateValue()

void DWARFExpression::UpdateValue ( uint64_t  const_value,
lldb::offset_t  const_value_byte_size,
uint8_t  addr_byte_size 

Member Data Documentation

◆ m_data

DataExtractor lldb_private::DWARFExpression::m_data

◆ m_reg_kind

lldb::RegisterKind lldb_private::DWARFExpression::m_reg_kind = lldb::eRegisterKindDWARF

One of the defines that starts with LLDB_REGKIND_.

Definition at line 163 of file DWARFExpression.h.

Referenced by GetRegisterKind(), MatchesOperand(), and SetRegisterKind().

The documentation for this class was generated from the following files: