class UnwindLocation

Declaration

class UnwindLocation { /* full declaration omitted */ };

Description

A class that represents a location for the Call Frame Address (CFA) or a register. This is decoded from the DWARF Call Frame Information instructions and put into an UnwindRow.

Declared at: llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h:36

Member Variables

private llvm::dwarf::UnwindLocation::Location Kind
private uint32_t RegNum
The type of the location that describes how to unwind it.
private int32_t Offset
The register number for Kind == RegPlusOffset.
private Optional<uint32_t> AddrSpace
The offset for Kind == CFAPlusOffset or RegPlusOffset.
private Optional<llvm::DWARFExpression> Expr
The address space for Kind == RegPlusOffset for CFA.
private bool Dereference
The DWARF expression for Kind == DWARFExpression.

Method Overview

Methods

UnwindLocation(
    llvm::dwarf::UnwindLocation::Location K,
    uint32_t Reg,
    int32_t Off,
    Optional<uint32_t> AS,
    bool Deref)

Declared at: llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h:83

Parameters

llvm::dwarf::UnwindLocation::Location K
uint32_t Reg
int32_t Off
Optional<uint32_t> AS
bool Deref

UnwindLocation(llvm::DWARFExpression E,
               bool Deref)

Declared at: llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h:87

Parameters

llvm::DWARFExpression E
bool Deref

UnwindLocation(
    llvm::dwarf::UnwindLocation::Location K)

Description

If true, the resulting location must be dereferenced after the location value is computed.

Declared at: llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h:79

Parameters

llvm::dwarf::UnwindLocation::Location K

static llvm::dwarf::UnwindLocation
createAtCFAPlusOffset(int32_t Off)

Declared at: llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h:109

Parameters

int32_t Off

static llvm::dwarf::UnwindLocation
createAtDWARFExpression(
    llvm::DWARFExpression Expr)

Declared at: llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h:128

Parameters

llvm::DWARFExpression Expr

static llvm::dwarf::UnwindLocation
createAtRegisterPlusOffset(
    uint32_t Reg,
    int32_t Off,
    Optional<uint32_t> AddrSpace = None)

Declared at: llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h:122

Parameters

uint32_t Reg
int32_t Off
Optional<uint32_t> AddrSpace = None

static llvm::dwarf::UnwindLocation
createIsCFAPlusOffset(int32_t Off)

Description

Create a location that is in (Deref == false) or at (Deref == true) the CFA plus an offset. Most registers that are spilled onto the stack use this rule. The rule for the register will use this rule and specify a unique offset from the CFA with \a Deref set to true. This value will be relative to a CFA value which is typically defined using the register plus offset location.

Declared at: llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h:108

Parameters

int32_t Off

static llvm::dwarf::UnwindLocation
createIsConstant(int32_t Value)

Declared at: llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h:129

Parameters

int32_t Value

static llvm::dwarf::UnwindLocation
createIsDWARFExpression(
    llvm::DWARFExpression Expr)

Description

Create a location whose value is the result of evaluating a DWARF expression. This allows complex expressions to be evaluated in order to unwind a register or CFA value.

Declared at: llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h:127

Parameters

llvm::DWARFExpression Expr

static llvm::dwarf::UnwindLocation
createIsRegisterPlusOffset(
    uint32_t Reg,
    int32_t Off,
    Optional<uint32_t> AddrSpace = None)

Description

Create a location where the saved value is in (Deref == false) or at (Deref == true) a regiser plus an offset and, optionally, in the specified address space (used mostly for the CFA). The CFA is usually defined using this rule by using the stack pointer or frame pointer as the register, with an offset that accounts for all spilled registers and all local variables in a function, and Deref == false.

Declared at: llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h:119

Parameters

uint32_t Reg
int32_t Off
Optional<uint32_t> AddrSpace = None

static llvm::dwarf::UnwindLocation createSame()

Description

Create a location where the value is known to be in the register itself.

Declared at: llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h:100

static llvm::dwarf::UnwindLocation
createUndefined()

Description

Create a location where the value is undefined and not available. This can happen when a register is volatile and can't be recovered.

Declared at: llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h:98

static llvm::dwarf::UnwindLocation
createUnspecified()

Description

Create a location whose rule is set to Unspecified. This means the register value might be in the same register but it wasn't specified in the unwind opcodes.

Declared at: llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h:95

void dump(llvm::raw_ostream& OS,
          const llvm::MCRegisterInfo* MRI,
          bool IsEH) const

Description

Dump a location expression as text and use the register information if some is provided.

Declared at: llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h:165

Parameters

llvm::raw_ostream& OS
the stream to use for output.
const llvm::MCRegisterInfo* MRI
register information that helps emit register names insteead of raw register numbers.
bool IsEH
true if the DWARF Call Frame Information is from .eh_frame instead of from .debug_frame. This is needed for register number conversion because some register numbers differ between the two sections for certain architectures like x86.

uint32_t getAddressSpace() const

Declared at: llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h:134

int32_t getConstant() const

Declared at: llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h:138

Optional<llvm::DWARFExpression>
getDWARFExpressionBytes() const

Declared at: llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h:152

llvm::dwarf::UnwindLocation::Location
getLocation() const

Declared at: llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h:131

int32_t getOffset() const

Declared at: llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h:133

uint32_t getRegister() const

Declared at: llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h:132

void setConstant(int32_t Value)

Description

Some opcodes modify a constant value and we need to be able to update the constant value (DW_CFA_GNU_window_save which is also known as

Declared at: llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h:150

Parameters

int32_t Value

void setOffset(int32_t NewOffset)

Description

Some opcodes will modify the CFA location's offset only, so we need to be able to modify the CFA offset when evaluating DWARF Call Frame Information opcodes.

Declared at: llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h:146

Parameters

int32_t NewOffset

void setRegister(uint32_t NewRegNum)

Description

Some opcodes will modify the CFA location's register only, so we need to be able to modify the CFA register when evaluating DWARF Call Frame Information opcodes.

Declared at: llvm/include/llvm/DebugInfo/DWARF/DWARFDebugFrame.h:142

Parameters

uint32_t NewRegNum