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c5feea4697
Teach IRGen to honor the linkage of SILWitnessTables, and teach SILGen to emit witness tables and protocol witness thunks for external definitions with shared linkage. Fixes <rdar://problem/16264703>. Swift SVN r14908
94 lines
3.2 KiB
C++
94 lines
3.2 KiB
C++
//===--- FormalLinkage.h - Formal linkage of types and decls ----*- C++ -*-===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2015 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See http://swift.org/LICENSE.txt for license information
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// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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#ifndef SWIFT_SIL_FORMALLINKAGE_H
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#define SWIFT_SIL_FORMALLINKAGE_H
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namespace swift {
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class CanType;
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class Decl;
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class ProtocolConformance;
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// Bits useful in defining the below.
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enum {
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// Bottom bit is uniqueness.
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FormalLinkage_Unique = 0x0,
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FormalLinkage_NonUnique = 0x1,
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// Higher bits are visibility, with greater values being more
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// restrictive.
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FormalLinkage_Public = 0 << 1,
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FormalLinkage_Hidden = 1 << 1,
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FormalLinkage_Private = 2 << 1,
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};
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/// Formal linkage is a property of types and declarations that
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/// informs, but is not completely equivalent to, the linkage of
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/// symbols corresponding to those types and declarations.
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///
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/// Forms a semilattice with ^ as the meet operator.
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enum class FormalLinkage {
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/// This entity is visible in multiple Swift modules and has a
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/// unique file that is known to define it.
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PublicUnique = FormalLinkage_Public | FormalLinkage_Unique,
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/// This entity is visible in multiple Swift modules, but does not
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/// have a unique file that is known to define it.
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PublicNonUnique = FormalLinkage_Public | FormalLinkage_NonUnique,
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/// This entity is visible in only a single Swift module and has a
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/// unique file that is known to define it.
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HiddenUnique = FormalLinkage_Hidden | FormalLinkage_Unique,
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/// This entity is visible in only a single Swift module but does not
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/// have a unique file that is known to define it.
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HiddenNonUnique = FormalLinkage_Hidden | FormalLinkage_NonUnique,
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/// This entity is visible in only a single Swift file.
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//
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// In reality, these are by definition unique, but we use the
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// non-unique flag to make merging more efficient.
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Private = FormalLinkage_Private | FormalLinkage_NonUnique,
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/// The top of the semilattice: (a ^ Top) == a.
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Top = PublicUnique,
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/// The bottom of the semilattice: (a ^ Bottom) == Bottom.
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Bottom = Private,
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};
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/// Merge two linkages to get the more restrictive.
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inline FormalLinkage operator^(FormalLinkage lhs, FormalLinkage rhs) {
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// Semantically, we want the more restrictive visibility; if that's
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// private, it's unique, and otherwise it's non-unique if either is
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// non-unique. This is more efficient if we define away the
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// special case for private by representing Private as non-unique.
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if (lhs < rhs) {
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return FormalLinkage(unsigned(rhs) |
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(unsigned(lhs) & FormalLinkage_NonUnique));
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} else {
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return FormalLinkage(unsigned(lhs) |
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(unsigned(rhs) & FormalLinkage_NonUnique));
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}
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}
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inline FormalLinkage &operator^=(FormalLinkage &lhs, FormalLinkage rhs) {
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return (lhs = lhs ^ rhs);
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}
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FormalLinkage getTypeLinkage(CanType type);
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FormalLinkage getDeclLinkage(Decl *decl);
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} // end swift namespace
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#endif
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