Record Class VarGen.BlockTransition

java.lang.Object

java.lang.Record

ghidra.pcode.emu.jit.gen.var.VarGen.BlockTransition

Record Components:

gen - the code generator

toRetire - the varnodes to retire on the transition

toBirth - the varnodes to birth on the transition

Enclosing interface:

VarGen<V extends JitVar>

public static record VarGen.BlockTransition(JitCodeGenerator gen, Set<Varnode> toRetire, Set<Varnode> toBirth)
extends Record

A means to emit bytecode on transitions between blocks

Constructor Summary

Constructors

Constructor	Description
BlockTransition(JitCodeGenerator gen)	Construct a "nop" or blank transition.
BlockTransition(JitCodeGenerator gen, Set<Varnode> toRetire, Set<Varnode> toBirth)	Creates an instance of a BlockTransition record class.

Method Summary

Modifier and Type	Method	Description
final boolean	equals(Object o)	Indicates whether some other object is "equal to" this one.
JitCodeGenerator	gen()	Returns the value of the gen record component.
void	generate(org.objectweb.asm.MethodVisitor rv)	Emit bytecode for the transition
void	generateInv(org.objectweb.asm.MethodVisitor rv)	Emit bytecode for the reverse transition
final int	hashCode()	Returns a hash code value for this object.
boolean	needed()	Check if a transition is actually needed.
Set<Varnode>	toBirth()	Returns the value of the toBirth record component.
Set<Varnode>	toRetire()	Returns the value of the toRetire record component.
final String	toString()	Returns a string representation of this record class.

Methods inherited from class Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Details

BlockTransition

public BlockTransition(JitCodeGenerator gen)

Construct a "nop" or blank transition.

The transition is mutable, so it's common to create one in this fashion and then populate it.

Parameters:

gen - the code generator

BlockTransition

public BlockTransition(JitCodeGenerator gen,
 Set<Varnode> toRetire,
 Set<Varnode> toBirth)

Creates an instance of a BlockTransition record class.

Parameters:

gen - the value for the gen record component

toRetire - the value for the toRetire record component

toBirth - the value for the toBirth record component

Method Details

needed

public boolean needed()

Check if a transition is actually needed.

When a transition is not needed, some smaller control-flow constructs (e.g., in CBranchOpGen) can be averted.

Returns:

true if bytecode must be emitted

generate

public void generate(org.objectweb.asm.MethodVisitor rv)

Emit bytecode for the transition

Parameters:

rv - the visitor for the run method

generateInv

public void generateInv(org.objectweb.asm.MethodVisitor rv)

Emit bytecode for the reverse transition

Sometimes "transitions" are used around hazards, notably CallOtherOpGen. This method is used after the hazard to restore the live variables in scope. (generate(MethodVisitor) is used before the hazard.) Variables that were retired and re-birthed here. There should not have been any variables birthed going into the hazard.

Parameters:

rv - the visitor for the run method

toString

public final String toString()

Returns a string representation of this record class. The representation contains the name of the class, followed by the name and value of each of the record components.

Specified by:

toString in class Record

Returns:

a string representation of this object

hashCode

public final int hashCode()

Returns a hash code value for this object. The value is derived from the hash code of each of the record components.

Specified by:

hashCode in class Record

Returns:

a hash code value for this object

equals

public final boolean equals(Object o)

Indicates whether some other object is "equal to" this one. The objects are equal if the other object is of the same class and if all the record components are equal. All components in this record class are compared with Objects::equals(Object,Object).

Specified by:

equals in class Record

Parameters:

o - the object with which to compare

Returns:

true if this object is the same as the o argument; false otherwise.

gen

public JitCodeGenerator gen()

Returns the value of the gen record component.

Returns:

the value of the gen record component

toRetire

public Set<Varnode> toRetire()

Returns the value of the toRetire record component.

Returns:

the value of the toRetire record component

toBirth

public Set<Varnode> toBirth()

Returns the value of the toBirth record component.

Returns:

the value of the toBirth record component