Package ghidra.pcode.emu.jit.gen.op

Enum Class SubPieceOpGen

java.lang.Object

java.lang.Enum<SubPieceOpGen>

ghidra.pcode.emu.jit.gen.op.SubPieceOpGen

All Implemented Interfaces:

OpGen<JitSubPieceOp>, Serializable, Comparable<SubPieceOpGen>, Constable

public enum SubPieceOpGen
extends Enum<SubPieceOpGen>
implements OpGen<JitSubPieceOp>

The generator for a subpiece.

This is not quite like a normal binary operator, because the second operand is always a constant. It behaves more like a class of unary operators, if you ask me. Thus, we do not extend BinOpGen. We first emit code to load the operand. Then, because the shift amount is constant, we can deal with it at generation time. We emit code to shift right by that constant amount, accounting for bits and bytes. The masking, if required, is taken care of by the variable writing code, given the resulting type.

To avoid loading parts of the (left) operand that will just get dropped by this operator, we instead provide the subpiecing arguments (namely the offset and destination operand size) to the value-loading logic. This is done via the ValGen.subpiece(int, int) method. We can then load only those parts that are actually needed.

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Enum

Enum.EnumDesc<E extends Enum<E>>

Nested classes/interfaces inherited from interface ghidra.pcode.emu.jit.gen.op.OpGen

OpGen.DeadOpResult, OpGen.LiveOpResult, OpGen.OpResult

Enum Constant Summary

Enum Constants

Enum Constant	Description
GEN	The generator singleton

Method Summary

Modifier and Type	Method	Description
<THIS extends JitCompiledPassage> OpGen.OpResult	genRun(Emitter<Emitter.Bot> em, Local<Types.TRef<THIS>> localThis, Local<Types.TInt> localCtxmod, Methods.RetReq<Types.TRef<JitCompiledPassage.EntryPoint>> retReq, JitCodeGenerator<THIS> gen, JitSubPieceOp op, JitControlFlowModel.JitBlock block, Scope scope)	Emit bytecode into the run method.
static SubPieceOpGen	valueOf(String name)	Returns the enum constant of this class with the specified name.
static SubPieceOpGen[]	values()	Returns an array containing the constants of this enum class, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, describeConstable, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Details

GEN

public static final SubPieceOpGen GEN

The generator singleton

Method Details

values

public static SubPieceOpGen[] values()

Returns an array containing the constants of this enum class, in the order they are declared.

Returns:

an array containing the constants of this enum class, in the order they are declared

valueOf

public static SubPieceOpGen valueOf(String name)

Returns the enum constant of this class with the specified name. The string must match exactly an identifier used to declare an enum constant in this class. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum class has no constant with the specified name

NullPointerException - if the argument is null

genRun

public <THIS extends JitCompiledPassage>
OpGen.OpResult genRun(Emitter<Emitter.Bot> em,
 Local<Types.TRef<THIS>> localThis,
 Local<Types.TInt> localCtxmod,
 Methods.RetReq<Types.TRef<JitCompiledPassage.EntryPoint>> retReq,
 JitCodeGenerator<THIS> gen,
 JitSubPieceOp op,
 JitControlFlowModel.JitBlock block,
 Scope scope)

Description copied from interface: OpGen

Emit bytecode into the run method.

This method must emit the code needed to load any input operands, convert them to the appropriate type, perform the actual operation, and then if applicable, store the output operand. The implementations should delegate to JitCodeGenerator.genReadToStack(Emitter, Local, JitVal, ghidra.pcode.emu.jit.analysis.JitType.SimpleJitType, Ext), JitCodeGenerator.genWriteFromStack(Emitter, Local, JitVar, ghidra.pcode.emu.jit.analysis.JitType.SimpleJitType, Ext, Scope) or similar for mp-int types.

Specified by:

genRun in interface OpGen<JitSubPieceOp>

Type Parameters:

THIS - the type of the generated passage

Parameters:

em - the emitter typed with the empty stack

localThis - a handle to the local holding the this reference

localCtxmod - a handle to the local holding ctxmod

retReq - an indication of what must be returned by this JitCompiledPassage.run(int) method.

gen - the code generator

op - the p-code op (use-def node) to translate

block - the basic block containing the p-code op

scope - a scope for generating temporary local storage

Returns:

the result of emitting the p-code op's bytecode