retdec
Public Member Functions | Private Member Functions | List of all members
retdec::llvmir2hll::BitShiftOptimizer Class Referencefinal

Change bit shift to division or multiplication. More...

#include <bit_shift_optimizer.h>

Inheritance diagram for retdec::llvmir2hll::BitShiftOptimizer:
Inheritance graph
[legend]
Collaboration diagram for retdec::llvmir2hll::BitShiftOptimizer:
Collaboration graph
[legend]

Public Member Functions

 BitShiftOptimizer (ShPtr< Module > module)
 Constructs a new optimizer. More...
 
virtual std::string getId () const override
 Returns the ID of the optimizer. More...
 
- Public Member Functions inherited from retdec::llvmir2hll::Optimizer
 Optimizer (ShPtr< Module > module)
 Constructs a new optimizer. More...
 
ShPtr< Moduleoptimize ()
 Performs all the optimizations of the specific optimizer. 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< BitXorOpExpr > 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< DivOpExpr > 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< MulOpExpr > 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
 

Private Member Functions

void doOptimization () override
 Performs the optimization. More...
 
Visitor Interface
virtual void visit (ShPtr< BitShlOpExpr > expr) override
 
virtual void visit (ShPtr< BitShrOpExpr > expr) override
 
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< BitXorOpExpr > 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< DivOpExpr > 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< MulOpExpr > 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
 

Additional Inherited Members

- Static Public Member Functions inherited from retdec::llvmir2hll::Optimizer
template<class OptimizerType , typename... Args>
static ShPtr< Moduleoptimize (ShPtr< Module > module, Args &&... args)
 Creates an instance of OptimizerType with the given arguments and optimizes the given module by it. More...
 
- Protected Member Functions inherited from retdec::llvmir2hll::Optimizer
virtual void doInitialization ()
 Performs pre-optimization matters. More...
 
virtual void doFinalization ()
 Performs post-optimization matters. 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::Optimizer
ShPtr< Modulemodule
 The module that is being optimized. 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

Change bit shift to division or multiplication.

This optimizer removes bit shift operations and change them to division or multiplication.

A left arithmetical/logical shift by n is equivalent to multiplying by 2^n (provided the value does not overflow), while a right arithmetical shift by n of a two's complement value is equivalent to dividing by 2^n and rounding toward negative infinity.

Some conditions for the optimization:

  1. Left shift: IntType <<(logical/arithmetical) unsigned/signed(only >= 0) constant
  2. Right shift logical/arithmetical: unsigned IntType, unsigned/signed(only >=0) constant >>(logical/arithmetical) unsigned/signed(only >= 0) constant

Examples: The following left shift

return 8 << 2;

can be optimized to

return 8 * 4;

The following right shift

return 8 >> 2;

can be optimized to

return 8 / 4;

Instances of this class have reference object semantics.

This is a concrete optimizer which should not be subclassed.

Constructor & Destructor Documentation

◆ BitShiftOptimizer()

retdec::llvmir2hll::BitShiftOptimizer::BitShiftOptimizer ( ShPtr< Module module)

Constructs a new optimizer.

Parameters
[in]moduleModule to be optimized.
Preconditions
  • module is non-null

Member Function Documentation

◆ doOptimization()

void retdec::llvmir2hll::BitShiftOptimizer::doOptimization ( )
overrideprivatevirtual

Performs the optimization.

This function is called after doInitialization() and before doFinalization(), and should perform all the optimizations of the specific optimizer.

By default, this function does nothing.

Reimplemented from retdec::llvmir2hll::Optimizer.

◆ getId()

virtual std::string retdec::llvmir2hll::BitShiftOptimizer::getId ( ) const
inlineoverridevirtual

Returns the ID of the optimizer.

Implements retdec::llvmir2hll::Optimizer.

◆ visit() [1/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [2/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [3/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [4/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [5/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [6/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [7/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [8/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [9/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [10/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [11/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [12/71]

void retdec::llvmir2hll::BitShiftOptimizer::visit ( ShPtr< BitShlOpExpr expr)
overrideprivatevirtual

◆ visit() [13/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [14/71]

void retdec::llvmir2hll::BitShiftOptimizer::visit ( ShPtr< BitShrOpExpr expr)
overrideprivatevirtual

◆ visit() [15/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [16/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [17/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [18/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [19/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [20/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [21/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [22/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [23/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [24/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [25/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [26/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [27/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [28/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [29/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [30/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [31/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [32/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [33/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [34/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [35/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [36/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [37/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [38/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [39/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [40/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [41/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [42/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [43/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [44/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [45/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [46/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [47/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [48/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [49/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [50/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [51/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [52/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [53/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [54/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [55/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [56/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [57/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [58/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [59/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [60/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [61/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [62/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [63/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [64/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [65/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [66/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [67/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [68/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [69/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [70/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

◆ visit() [71/71]

void retdec::llvmir2hll::OrderedAllVisitor::visit
overrideprivate

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