mirror of
https://github.com/apple/swift.git
synced 2025-12-21 12:14:44 +01:00
b9b8f08f54
In preparation for implementing support for multiple-statement closure inference, switch closure constraint generation over to a statement visitor. Only the subset of statements that correspond to single-expression closures is currently handled; there is no way to enable this for multiple-statement closures yet.
131 lines
3.9 KiB
C++
131 lines
3.9 KiB
C++
//===--- CSClosure.cpp - Closures -----------------------------------------===//
|
|
//
|
|
// This source file is part of the Swift.org open source project
|
|
//
|
|
// Copyright (c) 2014 - 2018 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
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file implements constraint generation and solution application for
|
|
// closures. It provides part of the implementation of the ConstraintSystem
|
|
// class.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "ConstraintSystem.h"
|
|
using namespace swift;
|
|
using namespace swift::constraints;
|
|
|
|
namespace {
|
|
|
|
/// Statement visitor that generates constraints for a given closure body.
|
|
class ClosureConstraintGenerator
|
|
: public StmtVisitor<ClosureConstraintGenerator, void> {
|
|
friend StmtVisitor<ClosureConstraintGenerator, void>;
|
|
|
|
ConstraintSystem &cs;
|
|
ClosureExpr *closure;
|
|
Type closureResultType;
|
|
|
|
public:
|
|
/// Whether an error was encountered while generating constraints.
|
|
bool hadError = false;
|
|
|
|
ClosureConstraintGenerator(ConstraintSystem &cs, ClosureExpr *closure,
|
|
Type closureResultType)
|
|
: cs(cs), closure(closure), closureResultType(closureResultType) { }
|
|
|
|
private:
|
|
void visitDecl(Decl *decl) {
|
|
// Just ignore #if; the chosen children should appear in the
|
|
// surrounding context. This isn't good for source tools but it
|
|
// at least works.
|
|
if (isa<IfConfigDecl>(decl))
|
|
return;
|
|
|
|
// Skip #warning/#error; we'll handle them when applying the closure.
|
|
if (isa<PoundDiagnosticDecl>(decl))
|
|
return;
|
|
|
|
// Ignore variable declarations, because they're always handled within
|
|
// their enclosing pattern bindings.
|
|
if (isa<VarDecl>(decl))
|
|
return;
|
|
|
|
llvm_unreachable("Unimplemented case for closure body");
|
|
}
|
|
|
|
void visitBraceStmt(BraceStmt *braceStmt) {
|
|
for (auto node : braceStmt->getElements()) {
|
|
if (auto expr = node.dyn_cast<Expr *>()) {
|
|
auto generatedExpr = cs.generateConstraints(
|
|
expr, closure, /*isInputExpression=*/false);
|
|
if (!generatedExpr) {
|
|
hadError = true;
|
|
}
|
|
} else if (auto stmt = node.dyn_cast<Stmt *>()) {
|
|
visit(stmt);
|
|
} else {
|
|
visitDecl(node.get<Decl *>());
|
|
}
|
|
}
|
|
}
|
|
|
|
void visitReturnStmt(ReturnStmt *returnStmt) {
|
|
auto expr = returnStmt->getResult();
|
|
|
|
// FIXME: Implies Void return?
|
|
if (!expr)
|
|
return;
|
|
|
|
expr = cs.generateConstraints(expr, closure, /*isInputExpression=*/false);
|
|
if (!expr) {
|
|
hadError = true;
|
|
return;
|
|
}
|
|
|
|
// FIXME: Locator should point at the return statement?
|
|
bool hasReturn = hasExplicitResult(closure);
|
|
cs.addConstraint(
|
|
ConstraintKind::Conversion, cs.getType(expr),
|
|
closureResultType,
|
|
cs.getConstraintLocator(
|
|
closure, LocatorPathElt::ClosureBody(hasReturn)));
|
|
}
|
|
|
|
#define UNSUPPORTED_STMT(STMT) void visit##STMT##Stmt(STMT##Stmt *) { \
|
|
llvm_unreachable("Unsupported statement kind " #STMT); \
|
|
}
|
|
UNSUPPORTED_STMT(Yield)
|
|
UNSUPPORTED_STMT(Defer)
|
|
UNSUPPORTED_STMT(If)
|
|
UNSUPPORTED_STMT(Guard)
|
|
UNSUPPORTED_STMT(While)
|
|
UNSUPPORTED_STMT(Do)
|
|
UNSUPPORTED_STMT(DoCatch)
|
|
UNSUPPORTED_STMT(RepeatWhile)
|
|
UNSUPPORTED_STMT(ForEach)
|
|
UNSUPPORTED_STMT(Switch)
|
|
UNSUPPORTED_STMT(Case)
|
|
UNSUPPORTED_STMT(Break)
|
|
UNSUPPORTED_STMT(Continue)
|
|
UNSUPPORTED_STMT(Fallthrough)
|
|
UNSUPPORTED_STMT(Fail)
|
|
UNSUPPORTED_STMT(Throw)
|
|
UNSUPPORTED_STMT(PoundAssert)
|
|
#undef UNSUPPORTED_STMT
|
|
};
|
|
|
|
}
|
|
|
|
bool ConstraintSystem::generateConstraints(
|
|
ClosureExpr *closure, Type resultType) {
|
|
ClosureConstraintGenerator generator(*this, closure, resultType);
|
|
generator.visit(closure->getBody());
|
|
return generator.hadError;
|
|
}
|