LLVM  10.0.0svn
Public Member Functions | List of all members
llvm::AbstractState Struct Referenceabstract

An interface to query the internal state of an abstract attribute. More...

#include "llvm/Transforms/IPO/Attributor.h"

Inheritance diagram for llvm::AbstractState:
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Public Member Functions

virtual ~AbstractState ()
 
virtual bool isValidState () const =0
 Return if this abstract state is in a valid state. More...
 
virtual bool isAtFixpoint () const =0
 Return if this abstract state is fixed, thus does not need to be updated if information changes as it cannot change itself. More...
 
virtual ChangeStatus indicateOptimisticFixpoint ()=0
 Indicate that the abstract state should converge to the optimistic state. More...
 
virtual ChangeStatus indicatePessimisticFixpoint ()=0
 Indicate that the abstract state should converge to the pessimistic state. More...
 

Detailed Description

An interface to query the internal state of an abstract attribute.

The abstract state is a minimal interface that allows the Attributor to communicate with the abstract attributes about their internal state without enforcing or exposing implementation details, e.g., the (existence of an) underlying lattice.

It is sufficient to be able to query if a state is (1) valid or invalid, (2) at a fixpoint, and to indicate to the state that (3) an optimistic fixpoint was reached or (4) a pessimistic fixpoint was enforced.

All methods need to be implemented by the subclass. For the common use case, a single boolean state or a bit-encoded state, the BooleanState and IntegerState classes are already provided. An abstract attribute can inherit from them to get the abstract state interface and additional methods to directly modify the state based if needed. See the class comments for help.

Definition at line 765 of file Attributor.h.

Constructor & Destructor Documentation

◆ ~AbstractState()

virtual llvm::AbstractState::~AbstractState ( )
inlinevirtual

Definition at line 766 of file Attributor.h.

Member Function Documentation

◆ indicateOptimisticFixpoint()

virtual ChangeStatus llvm::AbstractState::indicateOptimisticFixpoint ( )
pure virtual

Indicate that the abstract state should converge to the optimistic state.

This will usually make the optimistically assumed state the known to be true state.

Returns
ChangeStatus::UNCHANGED as the assumed value should not change.

Implemented in llvm::DerefState, llvm::IntegerState, and AAReturnedValuesImpl.

Referenced by llvm::Attributor::run().

◆ indicatePessimisticFixpoint()

virtual ChangeStatus llvm::AbstractState::indicatePessimisticFixpoint ( )
pure virtual

Indicate that the abstract state should converge to the pessimistic state.

This will usually revert the optimistically assumed state to the known to be true state.

Returns
ChangeStatus::CHANGED as the assumed value may change.

Implemented in llvm::DerefState, llvm::IntegerState, and AAReturnedValuesImpl.

Referenced by llvm::Attributor::run().

◆ isAtFixpoint()

virtual bool llvm::AbstractState::isAtFixpoint ( ) const
pure virtual

Return if this abstract state is fixed, thus does not need to be updated if information changes as it cannot change itself.

Implemented in llvm::DerefState, llvm::IntegerState, and AAReturnedValuesImpl.

Referenced by llvm::operator<<(), and llvm::Attributor::run().

◆ isValidState()

virtual bool llvm::AbstractState::isValidState ( ) const
pure virtual

Return if this abstract state is in a valid state.

If false, no information provided should be used.

Implemented in llvm::DerefState, llvm::IntegerState, and AAReturnedValuesImpl.

Referenced by clampReturnedValueStates(), llvm::operator<<(), and llvm::Attributor::run().


The documentation for this struct was generated from the following file: