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

#include <DWARFExpression.h>

Classes
class	Delegate

Public Types
using	Stack = std::vector<Value>

Public Member Functions
	DWARFExpression ()
	DWARFExpression (const DataExtractor &data)
	Constructor.
	~DWARFExpression ()
	Destructor.
bool	IsValid () const
	Return true if the location expression contains data.
llvm::Expected< lldb::addr_t >	GetLocation_DW_OP_addr (const Delegate *dwarf_cu) const
	Return the address specified by the first DW_OP_{addr, addrx, GNU_addr_index} in the operation stream.
bool	Update_DW_OP_addr (const Delegate *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 Delegate *dwarf_cu) const
bool	LinkThreadLocalStorage (const Delegate *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, llvm::DIDumpOptions options={}) const
bool	MatchesOperand (StackFrame &frame, const Instruction::Operand &op) const

Static Public Member Functions
static llvm::Expected< Value >	Evaluate (ExecutionContext exe_ctx, RegisterContext reg_ctx, lldb::ModuleSP module_sp, const DataExtractor &opcodes, const Delegate dwarf_cu, const lldb::RegisterKind reg_set, const Value initial_value_ptr, const Value *object_address_ptr)
	Evaluate a DWARF location expression in a particular context.
static llvm::Error	ReadRegisterValueAsScalar (RegisterContext *reg_ctx, lldb::RegisterKind reg_kind, uint32_t reg_num, Value &value)

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.

Member Typedef Documentation

◆ Stack

using lldb_private::DWARFExpression::Stack = std::vector<Value>

Definition at line 38 of file DWARFExpression.h.

Constructor & Destructor Documentation

◆ DWARFExpression() [1/2]

DWARFExpression::DWARFExpression ( )

Definition at line 48 of file DWARFExpression.cpp.

References m_data.

◆ DWARFExpression() [2/2]

DWARFExpression::DWARFExpression ( const DataExtractor & data )

Constructor.

Parameters

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

Definition at line 50 of file DWARFExpression.cpp.

References m_data.

◆ ~DWARFExpression()

DWARFExpression::~DWARFExpression ( )

default

Destructor.

Member Function Documentation

◆ ContainsThreadLocalStorage()

bool DWARFExpression::ContainsThreadLocalStorage ( const Delegate * dwarf_cu ) const

Definition at line 492 of file DWARFExpression.cpp.

References GetOpcodeDataSize(), LLDB_INVALID_OFFSET, and m_data.

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

◆ DumpLocation()

void DWARFExpression::DumpLocation	(	Stream *	s,
		lldb::DescriptionLevel	level,
		ABI *	abi,
		llvm::DIDumpOptions	options = {} ) const

Definition at line 69 of file DWARFExpression.cpp.

References lldb_private::Stream::AsRawOstream(), lldb_private::ABI::GetMCRegisterInfo(), and m_data.

◆ Evaluate()

llvm::Expected< Value > DWARFExpression::Evaluate	(	ExecutionContext *	exe_ctx,
		RegisterContext *	reg_ctx,
		lldb::ModuleSP	module_sp,
		const DataExtractor &	opcodes,
		const Delegate *	dwarf_cu,
		const lldb::RegisterKind	reg_set,
		const Value *	initial_value_ptr,
		const Value *	object_address_ptr )

static

Evaluate a DWARF location expression in a particular context.

Parameters

[in]	exe_ctx	The 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_ctx	The module which defined the expression.
[in]	opcodes	This is a static method so the opcodes need to be provided explicitly.
[in]	reg_ctx	An 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_set	The call-frame-info style register kind.
[in]	initial_value_ptr	A value to put on top of the interpreter stack before evaluating the expression, if the expression is parametrized. Can be NULL.
[in]	result	A value into which the result of evaluating the expression is to be placed.
[in]	error_ptr	If non-NULL, used to report errors in expression evaluation.

Returns: 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 942 of file DWARFExpression.cpp.

Referenced by lldb_private::DWARFExpressionList::Evaluate(), and ExtractDataMemberLocation().

◆ GetExpressionData()

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

inline

Definition at line 157 of file DWARFExpression.h.

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

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

◆ GetLocation_DW_OP_addr()

llvm::Expected< lldb::addr_t > DWARFExpression::GetLocation_DW_OP_addr ( const Delegate * dwarf_cu ) const

Return the address specified by the first DW_OP_{addr, addrx, GNU_addr_index} in the operation stream.

Parameters

[in] dwarf_cu The dwarf unit this expression belongs to. Only required to resolve DW_OP{addrx, GNU_addr_index}.

Returns: The address specified by the operation, if the operation exists, or an llvm::Error otherwise.

Definition at line 405 of file DWARFExpression.cpp.

References DW_OP_value_to_name(), GetOpcodeDataSize(), LLDB_INVALID_ADDRESS, LLDB_INVALID_OFFSET, m_data, and lldb_private::DWARFExpression::Delegate::ReadAddressFromDebugAddrSection().

◆ GetRegisterKind()

RegisterKind DWARFExpression::GetRegisterKind ( ) const

Return the call-frame-info style register kind.

Definition at line 88 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 55 of file DWARFExpression.cpp.

References m_data.

◆ LinkThreadLocalStorage()

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