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swift-mirror/include/swift/SILOptimizer/Utils/Existential.h

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//===--- Existential.h - Existential related Analyses. -------*- C++ //-*-===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
#ifndef SWIFT_SILOPTIMIZER_UTILS_EXISTENTIAL_H
#define SWIFT_SILOPTIMIZER_UTILS_EXISTENTIAL_H
#include "swift/SIL/SILInstruction.h"
namespace swift {
/// Find InitExistential from global_addr and copy_addr.
SILValue findInitExistentialFromGlobalAddrAndCopyAddr(GlobalAddrInst *GAI,
CopyAddrInst *CAI);
/// Find InitExistential from global_addr and an apply argument.
SILValue findInitExistentialFromGlobalAddrAndApply(GlobalAddrInst *GAI,
ApplySite Apply, int ArgIdx);
/// Returns the address of an object with which the stack location \p ASI is
/// initialized. This is either a init_existential_addr or the destination of a
/// copy_addr. Returns a null value if the address does not dominate the
/// alloc_stack user \p ASIUser.
/// If the value is copied from another stack location, \p isCopied is set to
/// true.
SILValue getAddressOfStackInit(AllocStackInst *ASI, SILInstruction *ASIUser,
bool &isCopied);
/// Find the init_existential, which could be used to determine a concrete
/// type of the value used by \p openedUse.
/// If the value is copied from another stack location, \p isCopied is set to
/// true.
///
/// FIXME: replace all uses of this with ConcreteExistentialInfo.
SILInstruction *findInitExistential(Operand &openedUse,
ArchetypeType *&OpenedArchetype,
SILValue &OpenedArchetypeDef,
bool &isCopied);
/// Record conformance and concrete type info derived from an init_existential
/// value that is reopened before it's use. This is useful for finding the
/// concrete type of an apply's self argument. For example, an important pattern
/// for a class existential is:
///
/// %e = init_existential_ref %c : $C : $C, $P & Q
/// %o = open_existential_ref %e : $P & Q to $@opened("PQ") P & Q
/// %r = apply %f<@opened("PQ") P & Q>(%o)
/// : $@convention(method) <τ_0_0 where τ_0_0 : P, τ_0_0 : Q>
/// (@guaranteed τ_0_0) -> @owned τ_0_0
struct ConcreteExistentialInfo {
// The opened type passed as self. `$@opened("PQ")` above.
// This is also the replacement type of the method's Self type.
ArchetypeType *OpenedArchetype = nullptr;
// The definition of the OpenedArchetype.
SILValue OpenedArchetypeDef;
// True if the openedValue is copied from another stack location
bool isCopied;
// The init_existential instruction that produces the opened existential.
SILInstruction *InitExistential = nullptr;
// The existential type of the self argument before it is opened,
// produced by an init_existential.
CanType ExistentialType;
// The concrete type of self from the init_existential. `$C` above.
CanType ConcreteType;
// When ConcreteType is itself an opened existential, record the type
// definition. May be nullptr for a valid AppliedConcreteType.
SingleValueInstruction *ConcreteTypeDef = nullptr;
// The Substitution map derived from the init_existential.
// This maps a single generic parameter to the replacement ConcreteType
// and includes the full list of existential conformances.
// signature: <P & Q>, replacement: $C : conformances: [$P, $Q]
SubstitutionMap ExistentialSubs;
// The value of concrete type used to initialize the existential. `%c` above.
SILValue ConcreteValue;
// Search for a recognized pattern in which the given value is an opened
// existential that was previously initialized to a concrete type.
// Constructs a valid ConcreteExistentialInfo object if successfull.
ConcreteExistentialInfo(Operand &openedUse);
ConcreteExistentialInfo(ConcreteExistentialInfo &) = delete;
/// We do not not need to check for InitExistential not being not null
/// since if that were the case, we would have everything else null too.
bool isValid() const {
return OpenedArchetype && OpenedArchetypeDef && ConcreteType &&
!ExistentialSubs.empty() && ConcreteValue;
}
// Do a conformance lookup on ConcreteType with the given requirement, P. If P
// is satisfiable based on the existential's conformance, return the new
// conformance on P. Otherwise return None.
Optional<ProtocolConformanceRef>
lookupExistentialConformance(ProtocolDecl *P) const {
CanType selfTy = P->getSelfInterfaceType()->getCanonicalType();
return ExistentialSubs.lookupConformance(selfTy, P);
}
};
} // end namespace swift
#endif