struct AbstractState

Declaration

struct AbstractState { /* full declaration omitted */ };

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 {Inc,Dec,Bit}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.

Declared at: llvm/include/llvm/Transforms/IPO/Attributor.h:1216

Method Overview

Methods

virtual llvm::ChangeStatus
indicateOptimisticFixpoint()

Description

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.

Declared at: llvm/include/llvm/Transforms/IPO/Attributor.h:1233

Returns

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

virtual llvm::ChangeStatus
indicatePessimisticFixpoint()

Description

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.

Declared at: llvm/include/llvm/Transforms/IPO/Attributor.h:1241

Returns

ChangeStatus::CHANGED as the assumed value may change.

virtual bool isAtFixpoint() const

Description

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

Declared at: llvm/include/llvm/Transforms/IPO/Attributor.h:1225

virtual bool isValidState() const

Description

Return if this abstract state is in a valid state. If false, no information provided should be used.

Declared at: llvm/include/llvm/Transforms/IPO/Attributor.h:1221

virtual ~AbstractState()

Declared at: llvm/include/llvm/Transforms/IPO/Attributor.h:1217