Package ghidra.app.util.bin.format.dwarf.expression

Class DWARFExpressionEvaluator

java.lang.Object

ghidra.app.util.bin.format.dwarf.expression.DWARFExpressionEvaluator

public class DWARFExpressionEvaluator
extends Object

Evaluates a subset of DWARF expression opcodes.

Limitations:

Can not access memory during evaluation of expressions.
Some opcodes must be the last operation in the expression (deref, regX)
Can only specify offset from register for framebase and stack relative

Result can be a numeric value (ie. static address) or a register 'name' or a stack based offset.

Constructor Summary

Constructors

Constructor	Description
DWARFExpressionEvaluator(DWARFCompilationUnit cu)

Method Summary

Modifier and Type	Method	Description
DWARFExpressionResult	evaluate(byte[] exprBytes)
DWARFExpressionResult	evaluate(DWARFExpression _expr)
DWARFExpressionResult	evaluate(DWARFExpression _expr, long... stackArgs)
DWARFCompilationUnit	getDWARFCompilationUnit()
Register	getLastRegister()
int	getMaxStepCount()
int	getRawLastRegister()
String	getStackAsString()
Register	getTerminalRegister()	Returns the register that holds the contents of the object that the expression points to.
boolean	isDeref()
boolean	isDwarfStackValue()
boolean	isRegisterLocation()
boolean	isStackRelative()
long	peek()
long	pop()
void	push(long l)
DWARFExpression	readExpr(byte[] exprBytes)
void	setFrameBase(long fb)
void	setMaxStepCount(int maxStepCount)
String	toString()
boolean	useUnknownRegister()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Details

DWARFExpressionEvaluator

public DWARFExpressionEvaluator(DWARFCompilationUnit cu)

Method Details

getDWARFCompilationUnit

public DWARFCompilationUnit getDWARFCompilationUnit()

setFrameBase

public void setFrameBase(long fb)

push

public void push(long l)

peek

public long peek()
          throws DWARFExpressionException

Throws:

DWARFExpressionException

pop

public long pop()
         throws DWARFExpressionException

Throws:

DWARFExpressionException

getTerminalRegister

public Register getTerminalRegister()

Returns the register that holds the contents of the object that the expression points to.

Note, you should check isDeref() to see if the register is just a pointer to the object instead of the object itself.

Returns:

isDeref

public boolean isDeref()

readExpr

public DWARFExpression readExpr(byte[] exprBytes)
                         throws DWARFExpressionException

Throws:

DWARFExpressionException

evaluate

public DWARFExpressionResult evaluate(byte[] exprBytes)
                               throws DWARFExpressionException

Throws:

DWARFExpressionException

evaluate

public DWARFExpressionResult evaluate(DWARFExpression _expr,
 long... stackArgs)
                               throws DWARFExpressionException

Parameters:

_expr -

stackArgs - - pushed 0..N, so stackArgs[0] will be deepest, stackArgs[N] will be topmost.

Returns:

Throws:

DWARFExpressionException

evaluate

public DWARFExpressionResult evaluate(DWARFExpression _expr)
                               throws DWARFExpressionException

Throws:

DWARFExpressionException

getStackAsString

public String getStackAsString()

toString

public String toString()

Overrides:

toString in class Object

getMaxStepCount

public int getMaxStepCount()

setMaxStepCount

public void setMaxStepCount(int maxStepCount)

isDwarfStackValue

public boolean isDwarfStackValue()

useUnknownRegister

public boolean useUnknownRegister()

isRegisterLocation

public boolean isRegisterLocation()

getLastRegister

public Register getLastRegister()

getRawLastRegister

public int getRawLastRegister()

isStackRelative

public boolean isStackRelative()