retdec
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retdec::llvmir2hll::OneSubOptimizer Class Referencefinal

This optimizer changes expressions where one of the operands is a number one. Examples are mentioned below. More...

#include <one_sub_optimizer.h>

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Public Member Functions

 OneSubOptimizer (ShPtr< ArithmExprEvaluator > arithmExprEvaluator)
 Constructs the OneSubOptimizer. More...
 
virtual std::string getId () const override
 Returns the ID of the optimizer. More...
 
- Public Member Functions inherited from retdec::llvmir2hll::SubOptimizer
virtual bool tryOptimize (ShPtr< Expression > expr)
 Run optimization and try to optimize. More...
 
- Public Member Functions inherited from retdec::llvmir2hll::OrderedAllVisitor
virtual void visit (ShPtr< GlobalVarDef > varDef) override
 
virtual void visit (ShPtr< Function > func) override
 
virtual void visit (ShPtr< AssignStmt > stmt) override
 
virtual void visit (ShPtr< BreakStmt > stmt) override
 
virtual void visit (ShPtr< CallStmt > stmt) override
 
virtual void visit (ShPtr< ContinueStmt > stmt) override
 
virtual void visit (ShPtr< EmptyStmt > stmt) override
 
virtual void visit (ShPtr< ForLoopStmt > stmt) override
 
virtual void visit (ShPtr< UForLoopStmt > stmt) override
 
virtual void visit (ShPtr< GotoStmt > stmt) override
 
virtual void visit (ShPtr< IfStmt > stmt) override
 
virtual void visit (ShPtr< ReturnStmt > stmt) override
 
virtual void visit (ShPtr< SwitchStmt > stmt) override
 
virtual void visit (ShPtr< UnreachableStmt > stmt) override
 
virtual void visit (ShPtr< VarDefStmt > stmt) override
 
virtual void visit (ShPtr< WhileLoopStmt > stmt) override
 
virtual void visit (ShPtr< AddOpExpr > expr) override
 
virtual void visit (ShPtr< AddressOpExpr > expr) override
 
virtual void visit (ShPtr< AndOpExpr > expr) override
 
virtual void visit (ShPtr< ArrayIndexOpExpr > expr) override
 
virtual void visit (ShPtr< AssignOpExpr > expr) override
 
virtual void visit (ShPtr< BitAndOpExpr > expr) override
 
virtual void visit (ShPtr< BitOrOpExpr > expr) override
 
virtual void visit (ShPtr< BitShlOpExpr > expr) override
 
virtual void visit (ShPtr< BitShrOpExpr > expr) override
 
virtual void visit (ShPtr< CallExpr > expr) override
 
virtual void visit (ShPtr< CommaOpExpr > expr) override
 
virtual void visit (ShPtr< DerefOpExpr > expr) override
 
virtual void visit (ShPtr< EqOpExpr > expr) override
 
virtual void visit (ShPtr< GtEqOpExpr > expr) override
 
virtual void visit (ShPtr< GtOpExpr > expr) override
 
virtual void visit (ShPtr< LtEqOpExpr > expr) override
 
virtual void visit (ShPtr< LtOpExpr > expr) override
 
virtual void visit (ShPtr< ModOpExpr > expr) override
 
virtual void visit (ShPtr< NegOpExpr > expr) override
 
virtual void visit (ShPtr< NeqOpExpr > expr) override
 
virtual void visit (ShPtr< NotOpExpr > expr) override
 
virtual void visit (ShPtr< OrOpExpr > expr) override
 
virtual void visit (ShPtr< StructIndexOpExpr > expr) override
 
virtual void visit (ShPtr< SubOpExpr > expr) override
 
virtual void visit (ShPtr< TernaryOpExpr > expr) override
 
virtual void visit (ShPtr< Variable > var) override
 
virtual void visit (ShPtr< BitCastExpr > expr) override
 
virtual void visit (ShPtr< ExtCastExpr > expr) override
 
virtual void visit (ShPtr< FPToIntCastExpr > expr) override
 
virtual void visit (ShPtr< IntToFPCastExpr > expr) override
 
virtual void visit (ShPtr< IntToPtrCastExpr > expr) override
 
virtual void visit (ShPtr< PtrToIntCastExpr > expr) override
 
virtual void visit (ShPtr< TruncCastExpr > expr) override
 
virtual void visit (ShPtr< ConstArray > constant) override
 
virtual void visit (ShPtr< ConstBool > constant) override
 
virtual void visit (ShPtr< ConstFloat > constant) override
 
virtual void visit (ShPtr< ConstInt > constant) override
 
virtual void visit (ShPtr< ConstNullPointer > constant) override
 
virtual void visit (ShPtr< ConstString > constant) override
 
virtual void visit (ShPtr< ConstStruct > constant) override
 
virtual void visit (ShPtr< ConstSymbol > constant) override
 
virtual void visit (ShPtr< ArrayType > type) override
 
virtual void visit (ShPtr< FloatType > type) override
 
virtual void visit (ShPtr< IntType > type) override
 
virtual void visit (ShPtr< PointerType > type) override
 
virtual void visit (ShPtr< StringType > type) override
 
virtual void visit (ShPtr< StructType > type) override
 
virtual void visit (ShPtr< FunctionType > type) override
 
virtual void visit (ShPtr< VoidType > type) override
 
virtual void visit (ShPtr< UnknownType > type) override
 
- Public Member Functions inherited from retdec::llvmir2hll::Visitor
virtual ~Visitor ()=default
 

Static Public Member Functions

static ShPtr< SubOptimizercreate (ShPtr< ArithmExprEvaluator > arithmExprEvaluator)
 Creates a new OneSubOptimizer. More...
 

Private Member Functions

bool isConstFloatOne (ShPtr< Expression > expr) const
 Check if expression is a ConstFloat one. More...
 
bool isConstIntOne (ShPtr< Expression > expr) const
 Check if expression is a ConstInt one. More...
 
bool isOne (ShPtr< ConstFloat > value) const
 Determines whether the float constant has the value 1.0. More...
 
bool isOne (ShPtr< ConstInt > value) const
 Determines whether the constant integer has the value 1. More...
 
bool isOpOne (ShPtr< Expression > expr) const
 Check if expression is a ConstInt or ConstFloat number one. More...
 
Visitor Interface
virtual void visit (ShPtr< MulOpExpr > expr) override
 
virtual void visit (ShPtr< DivOpExpr > expr) override
 
virtual void visit (ShPtr< BitXorOpExpr > expr) override
 

Additional Inherited Members

- Protected Member Functions inherited from retdec::llvmir2hll::SubOptimizer
 SubOptimizer (ShPtr< ArithmExprEvaluator > arithmExprEvaluator)
 Constructs the SubOptimizer. More...
 
bool isConstFloatOrConstInt (ShPtr< Expression > expr) const
 Check if expression is a ConstInt or ConstFloat. More...
 
void optimizeExpr (ShPtr< Expression > oldExpr, ShPtr< Expression > newExpr)
 Optimize expression from oldExpr to newExpr. More...
 
bool tryOptimizeAndReturnIfCodeChanged (ShPtr< Expression > expr)
 Start traversal in abstract syntax tree. More...
 
- Protected Member Functions inherited from retdec::llvmir2hll::OrderedAllVisitor
 OrderedAllVisitor (bool visitSuccessors=true, bool visitNestedStmts=true)
 Constructs a new visitor. More...
 
virtual void visitStmt (ShPtr< Statement > stmt, bool visitSuccessors=true, bool visitNestedStmts=true)
 Visits the given statement, and possibly its successors or nested statements. More...
 
void restart (bool visitSuccessors=true, bool visitNestedStmts=true)
 "Restarts" the visitor so it is in the state like it was when it was created. More...
 
bool makeAccessedAndCheckIfAccessed (ShPtr< Type > type)
 Makes the given type accessed. More...
 
- Protected Member Functions inherited from retdec::llvmir2hll::Visitor
 Visitor ()=default
 
- Protected Attributes inherited from retdec::llvmir2hll::SubOptimizer
ShPtr< ArithmExprEvaluatorarithmExprEvaluator
 The used evaluator of arithmetical expressions. More...
 
- Protected Attributes inherited from retdec::llvmir2hll::OrderedAllVisitor
ShPtr< StatementlastStmt
 Statement that has been accessed as the last one. More...
 
StmtUSet accessedStmts
 A set of all accessed statements. More...
 
TypeUSet accessedTypes
 A set of all accessed types. More...
 
bool visitSuccessors
 Should statements' successor be accessed? More...
 
bool visitNestedStmts
 Should nested statements be accessed? More...
 

Detailed Description

This optimizer changes expressions where one of the operands is a number one. Examples are mentioned below.

Optimizations are now only on these operators: *, /, ^.

List of performed simplifications (by examples):

Operator ^
1 ^ (EqOpExpr) or (EqOpExpr) ^ 1.
return 1 ^ (a == b);
can be optimized to
return a != b;
1 ^ SomeCasts(EqOpExpr) or SomeCasts(EqOpExpr) ^ 1.
return 1 ^ IntToPtrCastExpr<int>(a == b);
can be optimized to
return a != b;
Operator *
1(ConstInt/ConstFloat) * anything (vica versa).
return 1 * a;
can be optimized to
return a;
Operator /
Anything / 1(ConstInt/ConstFloat).
return a / 1;
can be optimized to
return a;

Instances of this class have reference object semantics.

This is a concrete sub-optimizer which should not be subclassed.

Constructor & Destructor Documentation

◆ OneSubOptimizer()

retdec::llvmir2hll::OneSubOptimizer::OneSubOptimizer ( ShPtr< ArithmExprEvaluator arithmExprEvaluator)

Constructs the OneSubOptimizer.

Parameters
[in]arithmExprEvaluatorThe used evaluator of arithmetical expressions.

Member Function Documentation

◆ create()

ShPtr< SubOptimizer > retdec::llvmir2hll::OneSubOptimizer::create ( ShPtr< ArithmExprEvaluator arithmExprEvaluator)
static

Creates a new OneSubOptimizer.

Parameters
[in]arithmExprEvaluatorThe used evaluator of arithmetical expressions.

◆ getId()

std::string retdec::llvmir2hll::OneSubOptimizer::getId ( ) const
overridevirtual

Returns the ID of the optimizer.

Implements retdec::llvmir2hll::SubOptimizer.

◆ isConstFloatOne()

bool retdec::llvmir2hll::OneSubOptimizer::isConstFloatOne ( ShPtr< Expression expr) const
private

Check if expression is a ConstFloat one.

Parameters
[in]exprExpression to check.
Returns
true if expr is a ConstFloat one, otherwise false.

◆ isConstIntOne()

bool retdec::llvmir2hll::OneSubOptimizer::isConstIntOne ( ShPtr< Expression expr) const
private

Check if expression is a ConstInt one.

Parameters
[in]exprExpression to check.
Returns
true if expr is a ConstInt one, otherwise false.

◆ isOne() [1/2]

bool retdec::llvmir2hll::OneSubOptimizer::isOne ( ShPtr< ConstFloat value) const
private

Determines whether the float constant has the value 1.0.

Parameters
[in]valueA value to check.
Returns
true if value is a float constant with the value 1.0, otherwise false.

◆ isOne() [2/2]

bool retdec::llvmir2hll::OneSubOptimizer::isOne ( ShPtr< ConstInt value) const
private

Determines whether the constant integer has the value 1.

Parameters
[in]valueA value to check.
Returns
true if value is a constant integer with the value 1, otherwise false.

◆ isOpOne()

bool retdec::llvmir2hll::OneSubOptimizer::isOpOne ( ShPtr< Expression expr) const
private

Check if expression is a ConstInt or ConstFloat number one.

Parameters
[in]exprExpression to check.
Returns
true if expr is a ConstInt or ConstFloat one, otherwise false.

◆ visit() [1/3]

void retdec::llvmir2hll::OneSubOptimizer::visit ( ShPtr< BitXorOpExpr expr)
overrideprivatevirtual

◆ visit() [2/3]

void retdec::llvmir2hll::OneSubOptimizer::visit ( ShPtr< DivOpExpr expr)
overrideprivatevirtual

◆ visit() [3/3]

void retdec::llvmir2hll::OneSubOptimizer::visit ( ShPtr< MulOpExpr expr)
overrideprivatevirtual

The documentation for this class was generated from the following files: