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3c69f6a305
Introduce the notion of "one-way" binding constraints of the form $T0 one-way bind to $T1 which treats the type variables $T0 and $T1 as independent up until the point where $T1 simplifies down to a concrete type, at which point $T0 will be bound to that concrete type. $T0 won't be bound in any other way, so type information ends up being propagated right-to-left, only. This allows a constraint system to be broken up in more components that are solved independently. Specifically, the connected components algorithm now proceeds as follows: 1. Compute connected components, excluding one-way constraints from consideration. 2. Compute a directed graph amongst the components using only the one-way constraints, where an edge A -> B indicates that the type variables in component A need to be solved before those in component B. 3. Using the directed graph, compute the set of components that need to be solved before a given component. To utilize this, implement a new kind of solver step that handles the propagation of partial solutions across one-way constraints. This introduces a new kind of "split" within a connected component, where we collect each combination of partial solutions for the input components and (separately) try to solve the constraints in this component. Any correct solution from any of these attempts will then be recorded as a (partial) solution for this component. For example, consider: let _: Int8 = b ? Builtin.one_way(int8Or16(17)) : Builtin.one_way(int8Or16(42\ )) where int8Or16 is overloaded with types `(Int8) -> Int8` and `(Int16) -> Int16`. There are two one-way components (`int8Or16(17)`) and (`int8Or16(42)`), each of which can produce a value of type `Int8` or `Int16`. Those two components will be solved independently, and the partial solutions for each will be fed into the component that evaluates the ternary operator. There are four ways to attempt that evaluation: ``` [Int8, Int8] [Int8, Int16] [Int16, Int8] [Int16, Int16] To test this, introduce a new expression builtin `Builtin.one_way(x)` that introduces a one-way expression constraint binding the result of the expression 'x'. The builtin is meant to be used for testing purposes, and the one-way constraint expression itself can be synthesized by the type checker to introduce one-way constraints later on. Of these two, there are only two (partial) solutions that can work at all, because the types in the ternary operator need a common supertype: [Int8, Int8] [Int16, Int16] Therefore, these are the partial solutions that will be considered the results of the component containing the ternary expression. Note that only one of them meets the final constraint (convertibility to `Int8`), so the expression is well-formed. Part of rdar://problem/50150793.
790 lines
30 KiB
C++
790 lines
30 KiB
C++
//===--- Constraint.cpp - Constraint in the Type Checker ------------------===//
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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 - 2018 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 https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the \c Constraint class and its related types,
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// which is used by the constraint-based type checker to describe a
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// constraint that must be solved.
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//
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//===----------------------------------------------------------------------===//
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#include "Constraint.h"
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#include "ConstraintSystem.h"
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#include "swift/AST/Types.h"
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#include "swift/Basic/Compiler.h"
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#include "llvm/Support/Compiler.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Support/SaveAndRestore.h"
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#include <algorithm>
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using namespace swift;
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using namespace constraints;
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Constraint::Constraint(ConstraintKind kind, ArrayRef<Constraint *> constraints,
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ConstraintLocator *locator,
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ArrayRef<TypeVariableType *> typeVars)
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: Kind(kind), HasRestriction(false), IsActive(false), IsDisabled(false),
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RememberChoice(false), IsFavored(false),
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NumTypeVariables(typeVars.size()), Nested(constraints), Locator(locator) {
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assert(kind == ConstraintKind::Disjunction);
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std::uninitialized_copy(typeVars.begin(), typeVars.end(),
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getTypeVariablesBuffer().begin());
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}
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Constraint::Constraint(ConstraintKind Kind, Type First, Type Second,
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ConstraintLocator *locator,
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ArrayRef<TypeVariableType *> typeVars)
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: Kind(Kind), HasRestriction(false), IsActive(false), IsDisabled(false),
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RememberChoice(false), IsFavored(false),
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NumTypeVariables(typeVars.size()), Types{First, Second, Type()},
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Locator(locator) {
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switch (Kind) {
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case ConstraintKind::Bind:
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case ConstraintKind::Equal:
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case ConstraintKind::BindParam:
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case ConstraintKind::BindToPointerType:
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case ConstraintKind::Subtype:
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case ConstraintKind::Conversion:
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case ConstraintKind::BridgingConversion:
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case ConstraintKind::ArgumentConversion:
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case ConstraintKind::OperatorArgumentConversion:
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case ConstraintKind::ConformsTo:
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case ConstraintKind::LiteralConformsTo:
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case ConstraintKind::CheckedCast:
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case ConstraintKind::SelfObjectOfProtocol:
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case ConstraintKind::DynamicTypeOf:
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case ConstraintKind::EscapableFunctionOf:
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case ConstraintKind::OpenedExistentialOf:
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case ConstraintKind::OptionalObject:
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case ConstraintKind::FunctionInput:
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case ConstraintKind::FunctionResult:
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case ConstraintKind::OpaqueUnderlyingType:
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case ConstraintKind::OneWayBind:
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assert(!First.isNull());
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assert(!Second.isNull());
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break;
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case ConstraintKind::ApplicableFunction:
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case ConstraintKind::DynamicCallableApplicableFunction:
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assert(First->is<FunctionType>()
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&& "The left-hand side type should be a function type");
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break;
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case ConstraintKind::ValueMember:
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case ConstraintKind::UnresolvedValueMember:
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llvm_unreachable("Wrong constructor for member constraint");
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case ConstraintKind::Defaultable:
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assert(!First.isNull());
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assert(!Second.isNull());
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break;
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case ConstraintKind::BindOverload:
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llvm_unreachable("Wrong constructor for overload binding constraint");
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case ConstraintKind::Disjunction:
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llvm_unreachable("Disjunction constraints should use create()");
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case ConstraintKind::KeyPath:
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case ConstraintKind::KeyPathApplication:
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llvm_unreachable("Key path constraint takes three types");
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}
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std::uninitialized_copy(typeVars.begin(), typeVars.end(),
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getTypeVariablesBuffer().begin());
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}
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Constraint::Constraint(ConstraintKind Kind, Type First, Type Second, Type Third,
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ConstraintLocator *locator,
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ArrayRef<TypeVariableType *> typeVars)
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: Kind(Kind), HasRestriction(false), IsActive(false), IsDisabled(false),
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RememberChoice(false), IsFavored(false),
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NumTypeVariables(typeVars.size()), Types{First, Second, Third},
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Locator(locator) {
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switch (Kind) {
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case ConstraintKind::Bind:
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case ConstraintKind::Equal:
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case ConstraintKind::BindParam:
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case ConstraintKind::BindToPointerType:
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case ConstraintKind::Subtype:
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case ConstraintKind::Conversion:
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case ConstraintKind::BridgingConversion:
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case ConstraintKind::ArgumentConversion:
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case ConstraintKind::OperatorArgumentConversion:
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case ConstraintKind::ConformsTo:
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case ConstraintKind::LiteralConformsTo:
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case ConstraintKind::CheckedCast:
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case ConstraintKind::SelfObjectOfProtocol:
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case ConstraintKind::DynamicTypeOf:
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case ConstraintKind::EscapableFunctionOf:
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case ConstraintKind::OpenedExistentialOf:
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case ConstraintKind::OptionalObject:
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case ConstraintKind::ApplicableFunction:
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case ConstraintKind::DynamicCallableApplicableFunction:
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case ConstraintKind::ValueMember:
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case ConstraintKind::UnresolvedValueMember:
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case ConstraintKind::Defaultable:
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case ConstraintKind::BindOverload:
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case ConstraintKind::Disjunction:
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case ConstraintKind::FunctionInput:
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case ConstraintKind::FunctionResult:
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case ConstraintKind::OpaqueUnderlyingType:
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case ConstraintKind::OneWayBind:
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llvm_unreachable("Wrong constructor");
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case ConstraintKind::KeyPath:
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case ConstraintKind::KeyPathApplication:
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assert(!First.isNull());
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assert(!Second.isNull());
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assert(!Third.isNull());
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break;
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}
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std::uninitialized_copy(typeVars.begin(), typeVars.end(),
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getTypeVariablesBuffer().begin());
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}
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Constraint::Constraint(ConstraintKind kind, Type first, Type second,
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DeclName member, DeclContext *useDC,
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FunctionRefKind functionRefKind,
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ConstraintLocator *locator,
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ArrayRef<TypeVariableType *> typeVars)
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: Kind(kind), HasRestriction(false), IsActive(false), IsDisabled(false),
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RememberChoice(false), IsFavored(false),
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NumTypeVariables(typeVars.size()), Member{first, second, member, useDC},
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Locator(locator) {
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assert(kind == ConstraintKind::ValueMember ||
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kind == ConstraintKind::UnresolvedValueMember);
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TheFunctionRefKind = static_cast<unsigned>(functionRefKind);
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assert(getFunctionRefKind() == functionRefKind);
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assert(member && "Member constraint has no member");
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assert(useDC && "Member constraint has no use DC");
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std::copy(typeVars.begin(), typeVars.end(), getTypeVariablesBuffer().begin());
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}
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Constraint::Constraint(Type type, OverloadChoice choice, DeclContext *useDC,
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ConstraintFix *fix, ConstraintLocator *locator,
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ArrayRef<TypeVariableType *> typeVars)
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: Kind(ConstraintKind::BindOverload), TheFix(fix), HasRestriction(false),
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IsActive(false), IsDisabled(bool(fix)), RememberChoice(false),
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IsFavored(false),
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NumTypeVariables(typeVars.size()), Overload{type, choice, useDC},
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Locator(locator) {
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std::copy(typeVars.begin(), typeVars.end(), getTypeVariablesBuffer().begin());
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}
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Constraint::Constraint(ConstraintKind kind,
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ConversionRestrictionKind restriction, Type first,
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Type second, ConstraintLocator *locator,
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ArrayRef<TypeVariableType *> typeVars)
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: Kind(kind), Restriction(restriction), HasRestriction(true),
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IsActive(false), IsDisabled(false), RememberChoice(false),
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IsFavored(false),
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NumTypeVariables(typeVars.size()), Types{first, second, Type()},
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Locator(locator) {
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assert(!first.isNull());
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assert(!second.isNull());
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std::copy(typeVars.begin(), typeVars.end(), getTypeVariablesBuffer().begin());
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}
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Constraint::Constraint(ConstraintKind kind, ConstraintFix *fix, Type first,
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Type second, ConstraintLocator *locator,
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ArrayRef<TypeVariableType *> typeVars)
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: Kind(kind), TheFix(fix), HasRestriction(false), IsActive(false),
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IsDisabled(false), RememberChoice(false), IsFavored(false),
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NumTypeVariables(typeVars.size()), Types{first, second, Type()},
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Locator(locator) {
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assert(!first.isNull());
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assert(!second.isNull());
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std::copy(typeVars.begin(), typeVars.end(), getTypeVariablesBuffer().begin());
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}
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ProtocolDecl *Constraint::getProtocol() const {
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assert((Kind == ConstraintKind::ConformsTo ||
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Kind == ConstraintKind::LiteralConformsTo ||
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Kind == ConstraintKind::SelfObjectOfProtocol)
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&& "Not a conformance constraint");
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return Types.Second->castTo<ProtocolType>()->getDecl();
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}
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Constraint *Constraint::clone(ConstraintSystem &cs) const {
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switch (getKind()) {
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case ConstraintKind::Bind:
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case ConstraintKind::Equal:
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case ConstraintKind::BindParam:
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case ConstraintKind::BindToPointerType:
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case ConstraintKind::Subtype:
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case ConstraintKind::Conversion:
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case ConstraintKind::BridgingConversion:
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case ConstraintKind::ArgumentConversion:
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case ConstraintKind::OperatorArgumentConversion:
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case ConstraintKind::ConformsTo:
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case ConstraintKind::LiteralConformsTo:
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case ConstraintKind::CheckedCast:
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case ConstraintKind::DynamicTypeOf:
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case ConstraintKind::EscapableFunctionOf:
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case ConstraintKind::OpenedExistentialOf:
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case ConstraintKind::SelfObjectOfProtocol:
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case ConstraintKind::ApplicableFunction:
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case ConstraintKind::DynamicCallableApplicableFunction:
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case ConstraintKind::OptionalObject:
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case ConstraintKind::Defaultable:
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case ConstraintKind::FunctionInput:
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case ConstraintKind::FunctionResult:
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case ConstraintKind::OpaqueUnderlyingType:
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case ConstraintKind::OneWayBind:
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return create(cs, getKind(), getFirstType(), getSecondType(), getLocator());
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case ConstraintKind::BindOverload:
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return createBindOverload(cs, getFirstType(), getOverloadChoice(),
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getOverloadUseDC(), getLocator());
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case ConstraintKind::ValueMember:
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case ConstraintKind::UnresolvedValueMember:
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return createMember(cs, getKind(), getFirstType(), getSecondType(),
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getMember(), getMemberUseDC(), getFunctionRefKind(),
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getLocator());
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case ConstraintKind::Disjunction:
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return createDisjunction(cs, getNestedConstraints(), getLocator());
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case ConstraintKind::KeyPath:
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case ConstraintKind::KeyPathApplication:
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return create(cs, getKind(), getFirstType(), getSecondType(), getThirdType(),
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getLocator());
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}
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llvm_unreachable("Unhandled ConstraintKind in switch.");
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}
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void Constraint::print(llvm::raw_ostream &Out, SourceManager *sm) const {
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if (Kind == ConstraintKind::Disjunction) {
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Out << "disjunction";
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if (shouldRememberChoice())
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Out << " (remembered)";
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if (Locator) {
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Out << " [[";
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Locator->dump(sm, Out);
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Out << "]]";
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}
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Out << ":";
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interleave(getNestedConstraints(),
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[&](Constraint *constraint) {
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if (constraint->isDisabled())
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Out << "[disabled] ";
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constraint->print(Out, sm);
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},
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[&] { Out << " or "; });
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return;
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}
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getFirstType()->print(Out);
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bool skipSecond = false;
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switch (Kind) {
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case ConstraintKind::Bind: Out << " bind "; break;
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case ConstraintKind::Equal: Out << " equal "; break;
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case ConstraintKind::BindParam: Out << " bind param "; break;
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case ConstraintKind::BindToPointerType: Out << " bind to pointer "; break;
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case ConstraintKind::Subtype: Out << " subtype "; break;
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case ConstraintKind::Conversion: Out << " conv "; break;
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case ConstraintKind::OpaqueUnderlyingType: Out << " underlying type of opaque "; break;
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case ConstraintKind::BridgingConversion: Out << " bridging conv "; break;
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case ConstraintKind::ArgumentConversion: Out << " arg conv "; break;
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case ConstraintKind::OperatorArgumentConversion:
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Out << " operator arg conv "; break;
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case ConstraintKind::ConformsTo: Out << " conforms to "; break;
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case ConstraintKind::LiteralConformsTo: Out << " literal conforms to "; break;
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case ConstraintKind::CheckedCast: Out << " checked cast to "; break;
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case ConstraintKind::SelfObjectOfProtocol: Out << " Self type of "; break;
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case ConstraintKind::ApplicableFunction: Out << " applicable fn "; break;
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case ConstraintKind::DynamicCallableApplicableFunction:
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Out << " dynamic callable applicable fn "; break;
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case ConstraintKind::DynamicTypeOf: Out << " dynamicType type of "; break;
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case ConstraintKind::EscapableFunctionOf: Out << " @escaping type of "; break;
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case ConstraintKind::OpenedExistentialOf: Out << " opened archetype of "; break;
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case ConstraintKind::OneWayBind: Out << " one-way bind to "; break;
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case ConstraintKind::KeyPath:
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Out << " key path from ";
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getSecondType()->print(Out);
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Out << " -> ";
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getThirdType()->print(Out);
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skipSecond = true;
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break;
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case ConstraintKind::KeyPathApplication:
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Out << " key path projecting ";
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getSecondType()->print(Out);
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Out << " -> ";
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getThirdType()->print(Out);
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skipSecond = true;
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break;
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case ConstraintKind::OptionalObject:
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Out << " optional with object type "; break;
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case ConstraintKind::FunctionInput:
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Out << " bind function input of "; break;
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case ConstraintKind::FunctionResult:
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Out << " bind function result of "; break;
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case ConstraintKind::BindOverload: {
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Out << " bound to ";
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auto overload = getOverloadChoice();
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auto printDecl = [&] {
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auto decl = overload.getDecl();
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decl->dumpRef(Out);
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Out << " : " << decl->getInterfaceType();
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if (!sm || !decl->getLoc().isValid()) return;
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Out << " at ";
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decl->getLoc().print(Out, *sm);
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};
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switch (overload.getKind()) {
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case OverloadChoiceKind::Decl:
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Out << "decl ";
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printDecl();
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break;
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case OverloadChoiceKind::DeclViaDynamic:
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Out << "decl-via-dynamic ";
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printDecl();
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break;
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case OverloadChoiceKind::DeclViaBridge:
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Out << "decl-via-bridge ";
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printDecl();
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break;
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case OverloadChoiceKind::DeclViaUnwrappedOptional:
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Out << "decl-via-unwrapped-optional ";
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printDecl();
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break;
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case OverloadChoiceKind::DynamicMemberLookup:
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case OverloadChoiceKind::KeyPathDynamicMemberLookup:
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Out << "dynamic member lookup '" << overload.getName() << "'";
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break;
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case OverloadChoiceKind::BaseType:
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Out << "base type";
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break;
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case OverloadChoiceKind::TupleIndex:
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Out << "tuple index " << overload.getTupleIndex();
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break;
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case OverloadChoiceKind::KeyPathApplication:
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Out << "key path application";
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break;
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}
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skipSecond = true;
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break;
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}
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case ConstraintKind::ValueMember:
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Out << "[." << Member.Member << ": value] == ";
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break;
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case ConstraintKind::UnresolvedValueMember:
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Out << "[(implicit) ." << Member.Member << ": value] == ";
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break;
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case ConstraintKind::Defaultable:
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Out << " can default to ";
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break;
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case ConstraintKind::Disjunction:
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llvm_unreachable("disjunction handled above");
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}
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if (!skipSecond)
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getSecondType()->print(Out);
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if (auto restriction = getRestriction()) {
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Out << ' ' << getName(*restriction);
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}
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if (auto *fix = getFix()) {
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Out << ' ';
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fix->print(Out);
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}
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if (Locator) {
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Out << " [[";
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Locator->dump(sm, Out);
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Out << "]];";
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}
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}
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void Constraint::dump(SourceManager *sm) const {
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print(llvm::errs(), sm);
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llvm::errs() << "\n";
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}
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void Constraint::dump(ConstraintSystem *CS) const {
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// Print all type variables as $T0 instead of _ here.
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llvm::SaveAndRestore<bool> X(CS->getASTContext().LangOpts.
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DebugConstraintSolver, true);
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// Disable MSVC warning: only for use within the debugger.
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#if SWIFT_COMPILER_IS_MSVC
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#pragma warning(push)
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#pragma warning(disable: 4996)
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#endif
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dump(&CS->getASTContext().SourceMgr);
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#if SWIFT_COMPILER_IS_MSVC
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#pragma warning(pop)
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#endif
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}
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StringRef swift::constraints::getName(ConversionRestrictionKind kind) {
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switch (kind) {
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case ConversionRestrictionKind::DeepEquality:
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return "[deep equality]";
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case ConversionRestrictionKind::Superclass:
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return "[superclass]";
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case ConversionRestrictionKind::Existential:
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return "[existential]";
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case ConversionRestrictionKind::MetatypeToExistentialMetatype:
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return "[metatype-to-existential-metatype]";
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case ConversionRestrictionKind::ExistentialMetatypeToMetatype:
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return "[existential-metatype-to-metatype]";
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case ConversionRestrictionKind::ValueToOptional:
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return "[value-to-optional]";
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case ConversionRestrictionKind::OptionalToOptional:
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return "[optional-to-optional]";
|
|
case ConversionRestrictionKind::ClassMetatypeToAnyObject:
|
|
return "[class-metatype-to-object]";
|
|
case ConversionRestrictionKind::ExistentialMetatypeToAnyObject:
|
|
return "[existential-metatype-to-object]";
|
|
case ConversionRestrictionKind::ProtocolMetatypeToProtocolClass:
|
|
return "[protocol-metatype-to-object]";
|
|
case ConversionRestrictionKind::ArrayToPointer:
|
|
return "[array-to-pointer]";
|
|
case ConversionRestrictionKind::StringToPointer:
|
|
return "[string-to-pointer]";
|
|
case ConversionRestrictionKind::InoutToPointer:
|
|
return "[inout-to-pointer]";
|
|
case ConversionRestrictionKind::PointerToPointer:
|
|
return "[pointer-to-pointer]";
|
|
case ConversionRestrictionKind::ArrayUpcast:
|
|
return "[array-upcast]";
|
|
case ConversionRestrictionKind::DictionaryUpcast:
|
|
return "[dictionary-upcast]";
|
|
case ConversionRestrictionKind::SetUpcast:
|
|
return "[set-upcast]";
|
|
case ConversionRestrictionKind::HashableToAnyHashable:
|
|
return "[hashable-to-anyhashable]";
|
|
case ConversionRestrictionKind::CFTollFreeBridgeToObjC:
|
|
return "[cf-toll-free-bridge-to-objc]";
|
|
case ConversionRestrictionKind::ObjCTollFreeBridgeToCF:
|
|
return "[objc-toll-free-bridge-to-cf]";
|
|
}
|
|
llvm_unreachable("bad conversion restriction kind");
|
|
}
|
|
|
|
/// Recursively gather the set of type variables referenced by this constraint.
|
|
static void
|
|
gatherReferencedTypeVars(Constraint *constraint,
|
|
SmallVectorImpl<TypeVariableType *> &typeVars) {
|
|
switch (constraint->getKind()) {
|
|
case ConstraintKind::Disjunction:
|
|
for (auto nested : constraint->getNestedConstraints())
|
|
gatherReferencedTypeVars(nested, typeVars);
|
|
return;
|
|
|
|
case ConstraintKind::KeyPath:
|
|
case ConstraintKind::KeyPathApplication:
|
|
constraint->getThirdType()->getTypeVariables(typeVars);
|
|
LLVM_FALLTHROUGH;
|
|
|
|
case ConstraintKind::ApplicableFunction:
|
|
case ConstraintKind::DynamicCallableApplicableFunction:
|
|
case ConstraintKind::Bind:
|
|
case ConstraintKind::BindParam:
|
|
case ConstraintKind::BindToPointerType:
|
|
case ConstraintKind::ArgumentConversion:
|
|
case ConstraintKind::Conversion:
|
|
case ConstraintKind::BridgingConversion:
|
|
case ConstraintKind::OperatorArgumentConversion:
|
|
case ConstraintKind::CheckedCast:
|
|
case ConstraintKind::Equal:
|
|
case ConstraintKind::Subtype:
|
|
case ConstraintKind::UnresolvedValueMember:
|
|
case ConstraintKind::ValueMember:
|
|
case ConstraintKind::DynamicTypeOf:
|
|
case ConstraintKind::EscapableFunctionOf:
|
|
case ConstraintKind::OpenedExistentialOf:
|
|
case ConstraintKind::OptionalObject:
|
|
case ConstraintKind::Defaultable:
|
|
case ConstraintKind::ConformsTo:
|
|
case ConstraintKind::LiteralConformsTo:
|
|
case ConstraintKind::SelfObjectOfProtocol:
|
|
case ConstraintKind::FunctionInput:
|
|
case ConstraintKind::FunctionResult:
|
|
case ConstraintKind::OpaqueUnderlyingType:
|
|
case ConstraintKind::OneWayBind:
|
|
constraint->getFirstType()->getTypeVariables(typeVars);
|
|
constraint->getSecondType()->getTypeVariables(typeVars);
|
|
break;
|
|
|
|
case ConstraintKind::BindOverload:
|
|
constraint->getFirstType()->getTypeVariables(typeVars);
|
|
|
|
// Special case: the base type of an overloading binding.
|
|
if (auto baseType = constraint->getOverloadChoice().getBaseType()) {
|
|
baseType->getTypeVariables(typeVars);
|
|
}
|
|
|
|
break;
|
|
}
|
|
}
|
|
|
|
/// Unique the given set of type variables.
|
|
static void uniqueTypeVariables(SmallVectorImpl<TypeVariableType *> &typeVars) {
|
|
// Remove any duplicate type variables.
|
|
llvm::SmallPtrSet<TypeVariableType *, 4> knownTypeVars;
|
|
typeVars.erase(std::remove_if(typeVars.begin(), typeVars.end(),
|
|
[&](TypeVariableType *typeVar) {
|
|
return !knownTypeVars.insert(typeVar).second;
|
|
}),
|
|
typeVars.end());
|
|
}
|
|
|
|
bool Constraint::isExplicitConversion() const {
|
|
assert(Kind == ConstraintKind::Disjunction);
|
|
|
|
if (auto *locator = getLocator()) {
|
|
if (auto anchor = locator->getAnchor())
|
|
return isa<CoerceExpr>(anchor);
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
Constraint *Constraint::create(ConstraintSystem &cs, ConstraintKind kind,
|
|
Type first, Type second,
|
|
ConstraintLocator *locator) {
|
|
// Collect type variables.
|
|
SmallVector<TypeVariableType *, 4> typeVars;
|
|
if (first->hasTypeVariable())
|
|
first->getTypeVariables(typeVars);
|
|
if (second && second->hasTypeVariable())
|
|
second->getTypeVariables(typeVars);
|
|
uniqueTypeVariables(typeVars);
|
|
|
|
// Conformance constraints expect an existential on the right-hand side.
|
|
assert((kind != ConstraintKind::ConformsTo &&
|
|
kind != ConstraintKind::SelfObjectOfProtocol) ||
|
|
second->isExistentialType());
|
|
|
|
// Literal protocol conformances expect a protocol.
|
|
assert((kind != ConstraintKind::LiteralConformsTo) ||
|
|
second->is<ProtocolType>());
|
|
|
|
// Create the constraint.
|
|
unsigned size = totalSizeToAlloc<TypeVariableType*>(typeVars.size());
|
|
void *mem = cs.getAllocator().Allocate(size, alignof(Constraint));
|
|
return ::new (mem) Constraint(kind, first, second, locator, typeVars);
|
|
}
|
|
|
|
Constraint *Constraint::create(ConstraintSystem &cs, ConstraintKind kind,
|
|
Type first, Type second, Type third,
|
|
ConstraintLocator *locator) {
|
|
// Collect type variables.
|
|
SmallVector<TypeVariableType *, 4> typeVars;
|
|
if (first->hasTypeVariable())
|
|
first->getTypeVariables(typeVars);
|
|
if (second->hasTypeVariable())
|
|
second->getTypeVariables(typeVars);
|
|
if (third->hasTypeVariable())
|
|
third->getTypeVariables(typeVars);
|
|
uniqueTypeVariables(typeVars);
|
|
|
|
unsigned size = totalSizeToAlloc<TypeVariableType*>(typeVars.size());
|
|
void *mem = cs.getAllocator().Allocate(size, alignof(Constraint));
|
|
return ::new (mem) Constraint(kind,
|
|
first, second, third,
|
|
locator, typeVars);
|
|
}
|
|
|
|
Constraint *Constraint::createMemberOrOuterDisjunction(
|
|
ConstraintSystem &cs, ConstraintKind kind, Type first, Type second,
|
|
DeclName member, DeclContext *useDC, FunctionRefKind functionRefKind,
|
|
ArrayRef<OverloadChoice> outerAlternatives, ConstraintLocator *locator) {
|
|
auto memberConstraint = createMember(cs, kind, first, second, member,
|
|
useDC, functionRefKind, locator);
|
|
|
|
if (outerAlternatives.empty())
|
|
return memberConstraint;
|
|
|
|
SmallVector<Constraint *, 4> constraints;
|
|
constraints.push_back(memberConstraint);
|
|
memberConstraint->setFavored();
|
|
for (auto choice : outerAlternatives) {
|
|
constraints.push_back(
|
|
Constraint::createBindOverload(cs, first, choice, useDC, locator));
|
|
}
|
|
return Constraint::createDisjunction(cs, constraints, locator, ForgetChoice);
|
|
}
|
|
|
|
Constraint *Constraint::createMember(ConstraintSystem &cs, ConstraintKind kind,
|
|
Type first, Type second, DeclName member,
|
|
DeclContext *useDC,
|
|
FunctionRefKind functionRefKind,
|
|
ConstraintLocator *locator) {
|
|
// Collect type variables.
|
|
SmallVector<TypeVariableType *, 4> typeVars;
|
|
if (first->hasTypeVariable())
|
|
first->getTypeVariables(typeVars);
|
|
if (second->hasTypeVariable())
|
|
second->getTypeVariables(typeVars);
|
|
uniqueTypeVariables(typeVars);
|
|
|
|
// Create the constraint.
|
|
unsigned size = totalSizeToAlloc<TypeVariableType*>(typeVars.size());
|
|
void *mem = cs.getAllocator().Allocate(size, alignof(Constraint));
|
|
return new (mem) Constraint(kind, first, second, member, useDC,
|
|
functionRefKind, locator, typeVars);
|
|
}
|
|
|
|
Constraint *Constraint::createBindOverload(ConstraintSystem &cs, Type type,
|
|
OverloadChoice choice,
|
|
DeclContext *useDC,
|
|
ConstraintLocator *locator) {
|
|
return createFixedChoice(cs, type, choice, useDC, /*fix=*/nullptr, locator);
|
|
}
|
|
|
|
Constraint *Constraint::createRestricted(ConstraintSystem &cs,
|
|
ConstraintKind kind,
|
|
ConversionRestrictionKind restriction,
|
|
Type first, Type second,
|
|
ConstraintLocator *locator) {
|
|
// Collect type variables.
|
|
SmallVector<TypeVariableType *, 4> typeVars;
|
|
if (first->hasTypeVariable())
|
|
first->getTypeVariables(typeVars);
|
|
if (second->hasTypeVariable())
|
|
second->getTypeVariables(typeVars);
|
|
uniqueTypeVariables(typeVars);
|
|
|
|
// Create the constraint.
|
|
unsigned size = totalSizeToAlloc<TypeVariableType*>(typeVars.size());
|
|
void *mem = cs.getAllocator().Allocate(size, alignof(Constraint));
|
|
return new (mem) Constraint(kind, restriction, first, second, locator,
|
|
typeVars);
|
|
}
|
|
|
|
Constraint *Constraint::createFixed(ConstraintSystem &cs, ConstraintKind kind,
|
|
ConstraintFix *fix, Type first, Type second,
|
|
ConstraintLocator *locator) {
|
|
// Collect type variables.
|
|
SmallVector<TypeVariableType *, 4> typeVars;
|
|
if (first->hasTypeVariable())
|
|
first->getTypeVariables(typeVars);
|
|
if (second->hasTypeVariable())
|
|
second->getTypeVariables(typeVars);
|
|
uniqueTypeVariables(typeVars);
|
|
|
|
// Create the constraint.
|
|
unsigned size = totalSizeToAlloc<TypeVariableType*>(typeVars.size());
|
|
void *mem = cs.getAllocator().Allocate(size, alignof(Constraint));
|
|
return new (mem) Constraint(kind, fix, first, second, locator, typeVars);
|
|
}
|
|
|
|
Constraint *Constraint::createFixedChoice(ConstraintSystem &cs, Type type,
|
|
OverloadChoice choice,
|
|
DeclContext *useDC,
|
|
ConstraintFix *fix,
|
|
ConstraintLocator *locator) {
|
|
// Collect type variables.
|
|
SmallVector<TypeVariableType *, 4> typeVars;
|
|
if (type->hasTypeVariable())
|
|
type->getTypeVariables(typeVars);
|
|
if (auto baseType = choice.getBaseType()) {
|
|
baseType->getTypeVariables(typeVars);
|
|
}
|
|
|
|
// Create the constraint.
|
|
unsigned size = totalSizeToAlloc<TypeVariableType *>(typeVars.size());
|
|
void *mem = cs.getAllocator().Allocate(size, alignof(Constraint));
|
|
return new (mem) Constraint(type, choice, useDC, fix, locator, typeVars);
|
|
}
|
|
|
|
Constraint *Constraint::createDisjunction(ConstraintSystem &cs,
|
|
ArrayRef<Constraint *> constraints,
|
|
ConstraintLocator *locator,
|
|
RememberChoice_t rememberChoice) {
|
|
// Unwrap any disjunctions inside the disjunction constraint; we only allow
|
|
// disjunctions at the top level.
|
|
SmallVector<TypeVariableType *, 4> typeVars;
|
|
bool unwrappedAny = false;
|
|
SmallVector<Constraint *, 1> unwrapped;
|
|
unsigned index = 0;
|
|
for (auto constraint : constraints) {
|
|
// Gather type variables from this constraint.
|
|
gatherReferencedTypeVars(constraint, typeVars);
|
|
|
|
// If we have a nested disjunction, unwrap it.
|
|
if (constraint->getKind() == ConstraintKind::Disjunction) {
|
|
// If we haven't unwrapped anything before, copy all of the constraints
|
|
// we skipped.
|
|
if (!unwrappedAny) {
|
|
unwrapped.append(constraints.begin(), constraints.begin() + index);
|
|
unwrappedAny = true;
|
|
}
|
|
|
|
// Add all of the constraints in the disjunction.
|
|
unwrapped.append(constraint->getNestedConstraints().begin(),
|
|
constraint->getNestedConstraints().end());
|
|
} else if (unwrappedAny) {
|
|
// Since we unwrapped constraints before, add this constraint.
|
|
unwrapped.push_back(constraint);
|
|
}
|
|
++index;
|
|
}
|
|
|
|
// If we unwrapped anything, our list of constraints is the unwrapped list.
|
|
if (unwrappedAny)
|
|
constraints = unwrapped;
|
|
|
|
assert(!constraints.empty() && "Empty disjunction constraint");
|
|
|
|
// If there is a single constraint, this isn't a disjunction at all.
|
|
if (constraints.size() == 1) {
|
|
assert(!rememberChoice && "simplified an important disjunction?");
|
|
return constraints.front();
|
|
}
|
|
|
|
#ifndef NDEBUG
|
|
assert(!constraints.empty());
|
|
// Verify that all disjunction choices have the same left-hand side.
|
|
Type commonType;
|
|
assert(llvm::all_of(constraints, [&](const Constraint *choice) -> bool {
|
|
// if this disjunction is formed from "fixed"
|
|
// constraints let's not try to validate.
|
|
if (choice->HasRestriction || choice->getFix())
|
|
return true;
|
|
|
|
auto currentType = choice->getFirstType();
|
|
if (!commonType) {
|
|
commonType = currentType;
|
|
return true;
|
|
}
|
|
return commonType->isEqual(currentType);
|
|
}));
|
|
#endif
|
|
|
|
// Create the disjunction constraint.
|
|
uniqueTypeVariables(typeVars);
|
|
unsigned size = totalSizeToAlloc<TypeVariableType*>(typeVars.size());
|
|
void *mem = cs.getAllocator().Allocate(size, alignof(Constraint));
|
|
auto disjunction = new (mem) Constraint(ConstraintKind::Disjunction,
|
|
cs.allocateCopy(constraints), locator, typeVars);
|
|
disjunction->RememberChoice = (bool) rememberChoice;
|
|
return disjunction;
|
|
}
|
|
|
|
void *Constraint::operator new(size_t bytes, ConstraintSystem& cs,
|
|
size_t alignment) {
|
|
return ::operator new (bytes, cs, alignment);
|
|
}
|