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cbb32aae86
When matching a result builder in the constraint system, the closure has already been pre-checked so we don’t need to pre-check it again. Also, we can continue type checking even if the closure contained an `ErrorExpr` since result builders are now type checked like regular closures.
3124 lines
111 KiB
C++
3124 lines
111 KiB
C++
//===--- BuilderTransform.cpp - Result-builder transformation -----------===//
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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 routines associated with the result-builder
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// transformation.
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//
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//===----------------------------------------------------------------------===//
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#include "MiscDiagnostics.h"
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#include "TypeCheckAvailability.h"
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#include "TypeChecker.h"
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#include "swift/AST/ASTPrinter.h"
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#include "swift/AST/ASTVisitor.h"
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#include "swift/AST/ASTWalker.h"
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#include "swift/AST/NameLookup.h"
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#include "swift/AST/NameLookupRequests.h"
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#include "swift/AST/ParameterList.h"
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#include "swift/AST/TypeCheckRequests.h"
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#include "swift/Sema/ConstraintSystem.h"
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#include "swift/Sema/IDETypeChecking.h"
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#include "swift/Sema/SolutionResult.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/SmallVector.h"
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#include <iterator>
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#include <map>
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#include <memory>
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#include <tuple>
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#include <utility>
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using namespace swift;
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using namespace constraints;
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namespace {
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/// Find the first #available condition within the statement condition,
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/// or return NULL if there isn't one.
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const StmtConditionElement *findAvailabilityCondition(StmtCondition stmtCond) {
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for (const auto &cond : stmtCond) {
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switch (cond.getKind()) {
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case StmtConditionElement::CK_Boolean:
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case StmtConditionElement::CK_PatternBinding:
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case StmtConditionElement::CK_HasSymbol:
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continue;
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case StmtConditionElement::CK_Availability:
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return &cond;
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break;
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}
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}
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return nullptr;
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}
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class BuilderTransformerBase {
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protected:
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ASTContext &ctx;
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DeclContext *dc;
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ResultBuilder builder;
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public:
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BuilderTransformerBase(ConstraintSystem *cs, DeclContext *dc,
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Type builderType)
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: ctx(dc->getASTContext()), dc(dc), builder(cs, dc, builderType) {}
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virtual ~BuilderTransformerBase() {}
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protected:
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virtual Expr *buildCallIfWanted(SourceLoc loc, Identifier fnName,
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ArrayRef<Expr *> argExprs,
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ArrayRef<Identifier> argLabels) = 0;
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static bool isBuildableIfChainRecursive(IfStmt *ifStmt, unsigned &numPayloads,
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bool &isOptional) {
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// The 'then' clause contributes a payload.
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++numPayloads;
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// If there's an 'else' clause, it contributes payloads:
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if (auto elseStmt = ifStmt->getElseStmt()) {
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// If it's 'else if', it contributes payloads recursively.
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if (auto elseIfStmt = dyn_cast<IfStmt>(elseStmt)) {
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return isBuildableIfChainRecursive(elseIfStmt, numPayloads, isOptional);
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// Otherwise it's just the one.
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} else {
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++numPayloads;
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}
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// If not, the chain result is at least optional.
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} else {
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isOptional = true;
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}
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return true;
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}
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static bool hasUnconditionalElse(IfStmt *ifStmt) {
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if (auto *elseStmt = ifStmt->getElseStmt()) {
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if (auto *ifStmt = dyn_cast<IfStmt>(elseStmt))
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return hasUnconditionalElse(ifStmt);
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return true;
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}
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return false;
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}
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bool isBuildableIfChain(IfStmt *ifStmt, unsigned &numPayloads,
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bool &isOptional) {
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if (!isBuildableIfChainRecursive(ifStmt, numPayloads, isOptional))
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return false;
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// If there's a missing 'else', we need 'buildOptional' to exist.
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if (isOptional && !builder.supportsOptional())
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return false;
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// If there are multiple clauses, we need 'buildEither(first:)' and
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// 'buildEither(second:)' to both exist.
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if (numPayloads > 1) {
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if (!builder.supports(ctx.Id_buildEither, {ctx.Id_first}) ||
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!builder.supports(ctx.Id_buildEither, {ctx.Id_second}))
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return false;
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}
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return true;
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}
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/// Wrap a payload value in an expression which will produce a chain
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/// result (without `buildIf`).
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Expr *buildWrappedChainPayload(Expr *operand, unsigned payloadIndex,
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unsigned numPayloads, bool isOptional) {
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assert(payloadIndex < numPayloads);
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// Inject into the appropriate chain position.
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//
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// We produce a (left-biased) balanced binary tree of Eithers in order
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// to prevent requiring a linear number of injections in the worst case.
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// That is, if we have 13 clauses, we want to produce:
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//
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// /------------------Either------------\
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// /-------Either-------\ /--Either--\
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// /--Either--\ /--Either--\ /--Either--\ \
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// /-E-\ /-E-\ /-E-\ /-E-\ /-E-\ /-E-\ \
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// 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 1011 1100
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//
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// Note that a prefix of length D of the payload index acts as a path
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// through the tree to the node at depth D. On the rightmost path
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// through the tree (when this prefix is equal to the corresponding
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// prefix of the maximum payload index), the bits of the index mark
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// where Eithers are required.
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//
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// Since we naturally want to build from the innermost Either out, and
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// therefore work with progressively shorter prefixes, we can do it all
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// with right-shifts.
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for (auto path = payloadIndex, maxPath = numPayloads - 1; maxPath != 0;
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path >>= 1, maxPath >>= 1) {
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// Skip making Eithers on the rightmost path where they aren't required.
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// This isn't just an optimization: adding spurious Eithers could
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// leave us with unresolvable type variables if `buildEither` has
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// a signature like:
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// static func buildEither<T,U>(first value: T) -> Either<T,U>
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// which relies on unification to work.
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if (path == maxPath && !(maxPath & 1))
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continue;
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bool isSecond = (path & 1);
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operand =
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buildCallIfWanted(operand->getStartLoc(), ctx.Id_buildEither, operand,
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{isSecond ? ctx.Id_second : ctx.Id_first});
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}
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// Inject into Optional if required. We'll be adding the call to
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// `buildIf` after all the recursive calls are complete.
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if (isOptional) {
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operand = buildSomeExpr(operand);
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}
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return operand;
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}
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Expr *buildSomeExpr(Expr *arg) {
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auto optionalDecl = ctx.getOptionalDecl();
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auto optionalType = optionalDecl->getDeclaredType();
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auto loc = arg->getStartLoc();
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auto optionalTypeExpr =
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TypeExpr::createImplicitHack(loc, optionalType, ctx);
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auto someRef = new (ctx) UnresolvedDotExpr(
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optionalTypeExpr, loc, DeclNameRef(ctx.getIdentifier("some")),
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DeclNameLoc(loc), /*implicit=*/true);
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auto *argList = ArgumentList::forImplicitUnlabeled(ctx, {arg});
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return CallExpr::createImplicit(ctx, someRef, argList);
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}
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Expr *buildNoneExpr(SourceLoc endLoc) {
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auto optionalDecl = ctx.getOptionalDecl();
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auto optionalType = optionalDecl->getDeclaredType();
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auto optionalTypeExpr =
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TypeExpr::createImplicitHack(endLoc, optionalType, ctx);
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return new (ctx) UnresolvedDotExpr(optionalTypeExpr, endLoc,
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DeclNameRef(ctx.getIdentifier("none")),
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DeclNameLoc(endLoc), /*implicit=*/true);
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}
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};
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/// Visitor to classify the contents of the given closure.
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class BuilderClosureVisitor
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: private BuilderTransformerBase,
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private StmtVisitor<BuilderClosureVisitor, VarDecl *> {
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friend StmtVisitor<BuilderClosureVisitor, VarDecl *>;
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ConstraintSystem *cs;
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SkipUnhandledConstructInResultBuilder::UnhandledNode unhandledNode;
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/// Whether an error occurred during application of the builder closure,
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/// e.g., during constraint generation.
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bool hadError = false;
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/// The record of what happened when we applied the builder transform.
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AppliedBuilderTransform applied;
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/// Produce a builder call to the given named function with the given
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/// arguments.
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Expr *buildCallIfWanted(SourceLoc loc, Identifier fnName,
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ArrayRef<Expr *> argExprs,
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ArrayRef<Identifier> argLabels) override {
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if (!cs)
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return nullptr;
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return builder.buildCall(loc, fnName, argExprs, argLabels);
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}
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/// Capture the given expression into an implicitly-generated variable.
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VarDecl *captureExpr(Expr *expr, bool oneWay,
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llvm::PointerUnion<Stmt *, Expr *> forEntity = nullptr) {
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if (!cs)
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return nullptr;
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Expr *origExpr = expr;
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if (oneWay) {
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// Form a one-way constraint to prevent backward propagation.
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expr = new (ctx) OneWayExpr(expr);
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}
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// Generate constraints for this expression.
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expr = cs->generateConstraints(expr, dc);
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if (!expr) {
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hadError = true;
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return nullptr;
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}
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// Create the implicit variable.
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auto var = builder.buildVar(expr->getStartLoc());
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// Record the new variable and its corresponding expression & statement.
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if (auto forStmt = forEntity.dyn_cast<Stmt *>()) {
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applied.capturedStmts.insert({forStmt, { var, { expr } }});
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} else {
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if (auto forExpr = forEntity.dyn_cast<Expr *>())
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origExpr = forExpr;
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applied.capturedExprs.insert({origExpr, {var, expr}});
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}
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cs->setType(var, cs->getType(expr));
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return var;
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}
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public:
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BuilderClosureVisitor(ASTContext &ctx, ConstraintSystem *cs, DeclContext *dc,
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Type builderType, Type bodyResultType)
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: BuilderTransformerBase(cs, dc, builderType), cs(cs) {
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applied.builderType = builder.getType();
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applied.bodyResultType = bodyResultType;
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}
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/// Apply the builder transform to the given statement.
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Optional<AppliedBuilderTransform> apply(Stmt *stmt) {
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VarDecl *bodyVar = visit(stmt);
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if (!bodyVar)
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return None;
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applied.returnExpr = builder.buildVarRef(bodyVar, stmt->getEndLoc());
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// If there is a buildFinalResult(_:), call it.
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ASTContext &ctx = cs->getASTContext();
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if (builder.supports(ctx.Id_buildFinalResult, {Identifier()})) {
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applied.returnExpr = buildCallIfWanted(
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applied.returnExpr->getLoc(), ctx.Id_buildFinalResult,
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{ applied.returnExpr }, { Identifier() });
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}
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applied.returnExpr = cs->buildTypeErasedExpr(
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applied.returnExpr, dc, applied.bodyResultType, CTP_ReturnStmt);
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applied.returnExpr = cs->generateConstraints(applied.returnExpr, dc);
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if (!applied.returnExpr) {
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hadError = true;
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return None;
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}
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return std::move(applied);
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}
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/// Check whether the result builder can be applied to this statement.
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/// \returns the node that cannot be handled by this builder on failure.
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SkipUnhandledConstructInResultBuilder::UnhandledNode check(Stmt *stmt) {
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(void)visit(stmt);
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return unhandledNode;
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}
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protected:
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#define CONTROL_FLOW_STMT(StmtClass) \
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VarDecl *visit##StmtClass##Stmt(StmtClass##Stmt *stmt) { \
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if (!unhandledNode) \
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unhandledNode = stmt; \
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\
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return nullptr; \
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}
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void visitPatternBindingDecl(PatternBindingDecl *patternBinding) {
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// Enforce some restrictions on local variables inside a result builder.
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for (unsigned i : range(patternBinding->getNumPatternEntries())) {
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// The pattern binding must have an initial value expression.
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if (!patternBinding->isExplicitlyInitialized(i)) {
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if (!unhandledNode)
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unhandledNode = patternBinding;
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return;
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}
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// Each variable bound by the pattern must be stored, and cannot
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// have observers.
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SmallVector<VarDecl *, 8> variables;
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patternBinding->getPattern(i)->collectVariables(variables);
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for (auto *var : variables) {
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if (!var->getImplInfo().isSimpleStored()) {
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if (!unhandledNode)
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unhandledNode = patternBinding;
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return;
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}
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// Also check for invalid attributes.
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TypeChecker::checkDeclAttributes(var);
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}
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}
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// If there is a constraint system, generate constraints for the pattern
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// binding.
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if (cs) {
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SyntacticElementTarget target(patternBinding);
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if (cs->generateConstraints(target))
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hadError = true;
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}
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}
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void visitBraceElement(ASTNode node, SmallVectorImpl<Expr *> &expressions) {
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auto addChild = [&](VarDecl *childVar) {
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if (!childVar)
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return;
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expressions.push_back(builder.buildVarRef(childVar, childVar->getLoc()));
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};
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// Implicit returns in single-expression function bodies are treated
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// as the expression.
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if (auto returnStmt =
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dyn_cast_or_null<ReturnStmt>(node.dyn_cast<Stmt *>())) {
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assert(returnStmt->isImplicit());
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node = returnStmt->getResult();
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}
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if (auto stmt = node.dyn_cast<Stmt *>()) {
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addChild(visit(stmt));
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return;
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}
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if (auto decl = node.dyn_cast<Decl *>()) {
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// Just ignore #if; the chosen children should appear in the
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// surrounding context. This isn't good for source tools but it
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// at least works.
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if (isa<IfConfigDecl>(decl))
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return;
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// Skip #warning/#error; we'll handle them when applying the builder.
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if (isa<PoundDiagnosticDecl>(decl))
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return;
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// Pattern bindings are okay so long as all of the entries are
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// initialized.
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if (auto patternBinding = dyn_cast<PatternBindingDecl>(decl)) {
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visitPatternBindingDecl(patternBinding);
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return;
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}
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// Ignore variable declarations, because they're always handled within
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// their enclosing pattern bindings.
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if (isa<VarDecl>(decl))
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return;
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if (!unhandledNode)
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unhandledNode = decl;
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return;
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}
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auto expr = node.get<Expr *>();
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if (auto *SVE = dyn_cast<SingleValueStmtExpr>(expr)) {
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// This should never be treated as an expression in a result builder, it
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// should have statement semantics.
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visitBraceElement(SVE->getStmt(), expressions);
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return;
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}
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if (cs && builder.supports(ctx.Id_buildExpression)) {
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expr = buildCallIfWanted(expr->getLoc(), ctx.Id_buildExpression,
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{expr}, {Identifier()});
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}
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addChild(captureExpr(expr, /*oneWay=*/true, node.get<Expr *>()));
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}
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VarDecl *visitBraceStmt(BraceStmt *braceStmt) {
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SmallVector<Expr *, 4> expressions;
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for (auto node : braceStmt->getElements())
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visitBraceElement(node, expressions);
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if (!cs || hadError)
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return nullptr;
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Expr *call = nullptr;
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// If the builder supports `buildPartialBlock(first:)` and
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// `buildPartialBlock(accumulated:next:)`, use this to combine
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// subexpressions pairwise.
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if (!expressions.empty() && builder.canUseBuildPartialBlock()) {
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// NOTE: The current implementation uses one-way constraints in between
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// subexpressions. It's functionally equivalent to the following:
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// let v0 = Builder.buildPartialBlock(first: arg_0)
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// let v1 = Builder.buildPartialBlock(accumulated: arg_1, next: v0)
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// ...
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// return Builder.buildPartialBlock(accumulated: arg_n, next: ...)
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call = buildCallIfWanted(braceStmt->getStartLoc(),
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ctx.Id_buildPartialBlock,
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{expressions.front()},
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/*argLabels=*/{ctx.Id_first});
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for (auto *expr : llvm::drop_begin(expressions)) {
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call = buildCallIfWanted(braceStmt->getStartLoc(),
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ctx.Id_buildPartialBlock,
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{new (ctx) OneWayExpr(call), expr},
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{ctx.Id_accumulated, ctx.Id_next});
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}
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}
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// If `buildBlock` does not exist at this point, it could be the case that
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// `buildPartialBlock` did not have the sufficient availability for this
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// call site. Diagnose it.
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else if (!builder.supports(ctx.Id_buildBlock)) {
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ctx.Diags.diagnose(
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braceStmt->getStartLoc(),
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diag::result_builder_missing_available_buildpartialblock,
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builder.getType());
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return nullptr;
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}
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// Otherwise, call `buildBlock` on all subexpressions.
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else {
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// Call Builder.buildBlock(... args ...)
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call = buildCallIfWanted(braceStmt->getStartLoc(),
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ctx.Id_buildBlock, expressions,
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/*argLabels=*/{ });
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}
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if (!call)
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return nullptr;
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return captureExpr(call, /*oneWay=*/true, braceStmt);
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}
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VarDecl *visitDoStmt(DoStmt *doStmt) {
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auto childVar = visitBraceStmt(doStmt->getBody());
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if (!childVar)
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return nullptr;
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auto childRef = builder.buildVarRef(childVar, doStmt->getEndLoc());
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return captureExpr(childRef, /*oneWay=*/true, doStmt);
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}
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CONTROL_FLOW_STMT(Yield)
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CONTROL_FLOW_STMT(Forget)
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CONTROL_FLOW_STMT(Defer)
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VarDecl *visitIfStmt(IfStmt *ifStmt) {
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// Check whether the chain is buildable and whether it terminates
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// without an `else`.
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bool isOptional = false;
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unsigned numPayloads = 0;
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if (!isBuildableIfChain(ifStmt, numPayloads, isOptional)) {
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if (!unhandledNode)
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unhandledNode = ifStmt;
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return nullptr;
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}
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// Attempt to build the chain, propagating short-circuits, which
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// might arise either do to error or not wanting an expression.
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|
return buildIfChainRecursive(ifStmt, 0, numPayloads, isOptional,
|
|
/*isTopLevel=*/true);
|
|
}
|
|
|
|
/// Recursively build an if-chain: build an expression which will have
|
|
/// a value of the chain result type before any call to `buildIf`.
|
|
/// The expression will perform any necessary calls to `buildEither`,
|
|
/// and the result will have optional type if `isOptional` is true.
|
|
VarDecl *buildIfChainRecursive(IfStmt *ifStmt, unsigned payloadIndex,
|
|
unsigned numPayloads, bool isOptional,
|
|
bool isTopLevel = false) {
|
|
assert(payloadIndex < numPayloads);
|
|
|
|
// First generate constraints for the conditions. This can introduce
|
|
// variable bindings that will be used within the "then" branch.
|
|
if (cs && cs->generateConstraints(ifStmt->getCond(), dc)) {
|
|
hadError = true;
|
|
return nullptr;
|
|
}
|
|
|
|
// Make sure we recursively visit both sides even if we're not
|
|
// building expressions.
|
|
|
|
// Build the then clause. This will have the corresponding payload
|
|
// type (i.e. not wrapped in any way).
|
|
VarDecl *thenVar = visit(ifStmt->getThenStmt());
|
|
|
|
// Build the else clause, if present. If this is from an else-if,
|
|
// this will be fully wrapped; otherwise it will have the corresponding
|
|
// payload type (at index `payloadIndex + 1`).
|
|
assert(ifStmt->getElseStmt() || isOptional);
|
|
bool isElseIf = false;
|
|
Optional<VarDecl *> elseChainVar;
|
|
if (auto elseStmt = ifStmt->getElseStmt()) {
|
|
if (auto elseIfStmt = dyn_cast<IfStmt>(elseStmt)) {
|
|
isElseIf = true;
|
|
elseChainVar = buildIfChainRecursive(elseIfStmt, payloadIndex + 1,
|
|
numPayloads, isOptional);
|
|
} else {
|
|
elseChainVar = visit(elseStmt);
|
|
}
|
|
}
|
|
|
|
// Short-circuit if appropriate.
|
|
if (!cs || !thenVar || (elseChainVar && !*elseChainVar))
|
|
return nullptr;
|
|
|
|
Expr *thenVarRefExpr =
|
|
builder.buildVarRef(thenVar, ifStmt->getThenStmt()->getEndLoc());
|
|
|
|
// If there is a #available in the condition, wrap the 'then' in a call to
|
|
// buildLimitedAvailability(_:).
|
|
auto availabilityCond = findAvailabilityCondition(ifStmt->getCond());
|
|
bool supportsAvailability =
|
|
availabilityCond && builder.supports(ctx.Id_buildLimitedAvailability);
|
|
if (supportsAvailability &&
|
|
!availabilityCond->getAvailability()->isUnavailability()) {
|
|
thenVarRefExpr = buildCallIfWanted(ifStmt->getThenStmt()->getEndLoc(),
|
|
ctx.Id_buildLimitedAvailability,
|
|
{thenVarRefExpr}, {Identifier()});
|
|
}
|
|
|
|
// Prepare the `then` operand by wrapping it to produce a chain result.
|
|
Expr *thenExpr = buildWrappedChainPayload(
|
|
thenVarRefExpr, payloadIndex, numPayloads, isOptional);
|
|
|
|
// Prepare the `else operand:
|
|
Expr *elseExpr;
|
|
SourceLoc elseLoc;
|
|
|
|
// - If there's no `else` clause, use `Optional.none`.
|
|
if (!elseChainVar) {
|
|
assert(isOptional);
|
|
elseLoc = ifStmt->getEndLoc();
|
|
elseExpr = buildNoneExpr(elseLoc);
|
|
|
|
// - If there's an `else if`, the chain expression from that
|
|
// should already be producing a chain result.
|
|
} else if (isElseIf) {
|
|
elseExpr = builder.buildVarRef(*elseChainVar, ifStmt->getEndLoc());
|
|
elseLoc = ifStmt->getElseLoc();
|
|
|
|
// - Otherwise, wrap it to produce a chain result.
|
|
} else {
|
|
Expr *elseVarRefExpr =
|
|
builder.buildVarRef(*elseChainVar, ifStmt->getEndLoc());
|
|
|
|
// If there is a #unavailable in the condition, wrap the 'else' in a call
|
|
// to buildLimitedAvailability(_:).
|
|
if (supportsAvailability &&
|
|
availabilityCond->getAvailability()->isUnavailability()) {
|
|
elseVarRefExpr = buildCallIfWanted(ifStmt->getEndLoc(),
|
|
ctx.Id_buildLimitedAvailability,
|
|
{elseVarRefExpr}, {Identifier()});
|
|
}
|
|
|
|
elseExpr = buildWrappedChainPayload(elseVarRefExpr, payloadIndex + 1,
|
|
numPayloads, isOptional);
|
|
elseLoc = ifStmt->getElseLoc();
|
|
}
|
|
|
|
// The operand should have optional type if we had optional results,
|
|
// so we just need to call `buildIf` now, since we're at the top level.
|
|
if (isOptional && isTopLevel) {
|
|
thenExpr =
|
|
buildCallIfWanted(ifStmt->getEndLoc(), builder.getBuildOptionalId(),
|
|
thenExpr, /*argLabels=*/{});
|
|
elseExpr =
|
|
buildCallIfWanted(ifStmt->getEndLoc(), builder.getBuildOptionalId(),
|
|
elseExpr, /*argLabels=*/{});
|
|
}
|
|
|
|
thenExpr = cs->generateConstraints(thenExpr, dc);
|
|
if (!thenExpr) {
|
|
hadError = true;
|
|
return nullptr;
|
|
}
|
|
|
|
elseExpr = cs->generateConstraints(elseExpr, dc);
|
|
if (!elseExpr) {
|
|
hadError = true;
|
|
return nullptr;
|
|
}
|
|
|
|
Type resultType = cs->addJoinConstraint(cs->getConstraintLocator(ifStmt),
|
|
{
|
|
{ cs->getType(thenExpr), cs->getConstraintLocator(thenExpr) },
|
|
{ cs->getType(elseExpr), cs->getConstraintLocator(elseExpr) }
|
|
});
|
|
if (!resultType) {
|
|
hadError = true;
|
|
return nullptr;
|
|
}
|
|
|
|
// Create a variable to capture the result of this expression.
|
|
auto ifVar = builder.buildVar(ifStmt->getStartLoc());
|
|
cs->setType(ifVar, resultType);
|
|
applied.capturedStmts.insert({ifStmt, { ifVar, { thenExpr, elseExpr }}});
|
|
return ifVar;
|
|
}
|
|
|
|
VarDecl *visitSwitchStmt(SwitchStmt *switchStmt) {
|
|
// Generate constraints for the subject expression, and capture its
|
|
// type for use in matching the various patterns.
|
|
Expr *subjectExpr = switchStmt->getSubjectExpr();
|
|
if (cs) {
|
|
// Form a one-way constraint to prevent backward propagation.
|
|
subjectExpr = new (ctx) OneWayExpr(subjectExpr);
|
|
|
|
// FIXME: Add contextual type purpose for switch subjects?
|
|
SyntacticElementTarget target(subjectExpr, dc, CTP_Unused, Type(),
|
|
/*isDiscarded=*/false);
|
|
if (cs->generateConstraints(target)) {
|
|
hadError = true;
|
|
return nullptr;
|
|
}
|
|
|
|
cs->setTargetFor(switchStmt, target);
|
|
subjectExpr = target.getAsExpr();
|
|
assert(subjectExpr && "Must have a subject expression here");
|
|
}
|
|
|
|
// Generate constraints and capture variables for all of the cases.
|
|
SmallVector<std::pair<CaseStmt *, VarDecl *>, 4> capturedCaseVars;
|
|
for (auto *caseStmt : switchStmt->getCases()) {
|
|
if (auto capturedCaseVar = visitCaseStmt(caseStmt, subjectExpr)) {
|
|
capturedCaseVars.push_back({caseStmt, capturedCaseVar});
|
|
}
|
|
}
|
|
|
|
if (!cs)
|
|
return nullptr;
|
|
|
|
// If there are no 'case' statements in the body let's try
|
|
// to diagnose this situation via limited exhaustiveness check
|
|
// before failing a builder transform, otherwise type-checker
|
|
// might end up without any diagnostics which leads to crashes
|
|
// in SILGen.
|
|
if (capturedCaseVars.empty()) {
|
|
TypeChecker::checkSwitchExhaustiveness(switchStmt, dc,
|
|
/*limitChecking=*/true);
|
|
hadError = true;
|
|
return nullptr;
|
|
}
|
|
|
|
// Form the expressions that inject the result of each case into the
|
|
// appropriate
|
|
llvm::TinyPtrVector<Expr *> injectedCaseExprs;
|
|
SmallVector<std::pair<Type, ConstraintLocator *>, 4> injectedCaseTerms;
|
|
for (unsigned idx : indices(capturedCaseVars)) {
|
|
auto caseStmt = capturedCaseVars[idx].first;
|
|
auto caseVar = capturedCaseVars[idx].second;
|
|
|
|
// Build the expression that injects the case variable into appropriate
|
|
// buildEither(first:)/buildEither(second:) chain.
|
|
Expr *caseVarRef = builder.buildVarRef(caseVar, caseStmt->getEndLoc());
|
|
Expr *injectedCaseExpr = buildWrappedChainPayload(
|
|
caseVarRef, idx, capturedCaseVars.size(), /*isOptional=*/false);
|
|
|
|
// Generate constraints for this injected case result.
|
|
injectedCaseExpr = cs->generateConstraints(injectedCaseExpr, dc);
|
|
if (!injectedCaseExpr) {
|
|
hadError = true;
|
|
return nullptr;
|
|
}
|
|
|
|
// Record this injected case expression.
|
|
injectedCaseExprs.push_back(injectedCaseExpr);
|
|
|
|
// Record the type and locator for this injected case expression, to be
|
|
// used in the "join" constraint later.
|
|
injectedCaseTerms.push_back(
|
|
{ cs->getType(injectedCaseExpr)->getRValueType(),
|
|
cs->getConstraintLocator(injectedCaseExpr) });
|
|
}
|
|
|
|
// Form the type of the switch itself.
|
|
Type resultType = cs->addJoinConstraint(
|
|
cs->getConstraintLocator(switchStmt), injectedCaseTerms);
|
|
if (!resultType) {
|
|
hadError = true;
|
|
return nullptr;
|
|
}
|
|
|
|
// Create a variable to capture the result of evaluating the switch.
|
|
auto switchVar = builder.buildVar(switchStmt->getStartLoc());
|
|
cs->setType(switchVar, resultType);
|
|
applied.capturedStmts.insert(
|
|
{switchStmt, { switchVar, std::move(injectedCaseExprs) } });
|
|
return switchVar;
|
|
}
|
|
|
|
VarDecl *visitCaseStmt(CaseStmt *caseStmt, Expr *subjectExpr) {
|
|
auto *body = caseStmt->getBody();
|
|
|
|
// Explicitly disallow `case` statements with empty bodies
|
|
// since that helps to diagnose other issues with switch
|
|
// statements by excluding invalid cases.
|
|
if (auto *BS = dyn_cast<BraceStmt>(body)) {
|
|
if (BS->getNumElements() == 0) {
|
|
// HACK: still allow empty bodies if typechecking for code
|
|
// completion. Code completion ignores diagnostics
|
|
// and won't get any types if we fail.
|
|
if (!ctx.SourceMgr.hasIDEInspectionTargetBuffer()) {
|
|
hadError = true;
|
|
return nullptr;
|
|
}
|
|
}
|
|
}
|
|
|
|
// If needed, generate constraints for everything in the case statement.
|
|
if (cs) {
|
|
auto locator = cs->getConstraintLocator(
|
|
subjectExpr, LocatorPathElt::ContextualType(CTP_CaseStmt));
|
|
Type subjectType = cs->getType(subjectExpr);
|
|
|
|
if (cs->generateConstraints(caseStmt, dc, subjectType, locator)) {
|
|
hadError = true;
|
|
return nullptr;
|
|
}
|
|
}
|
|
|
|
// Translate the body.
|
|
return visit(caseStmt->getBody());
|
|
}
|
|
|
|
VarDecl *visitForEachStmt(ForEachStmt *forEachStmt) {
|
|
// for...in statements are handled via buildArray(_:); bail out if the
|
|
// builder does not support it.
|
|
if (!builder.supports(ctx.Id_buildArray)) {
|
|
if (!unhandledNode)
|
|
unhandledNode = forEachStmt;
|
|
return nullptr;
|
|
}
|
|
|
|
// Generate constraints for the loop header. This also wires up the
|
|
// types for the patterns.
|
|
auto target = SyntacticElementTarget::forForEachStmt(
|
|
forEachStmt, dc, /*bindPatternVarsOneWay=*/true);
|
|
if (cs) {
|
|
if (cs->generateConstraints(target)) {
|
|
hadError = true;
|
|
return nullptr;
|
|
}
|
|
|
|
cs->setTargetFor(forEachStmt, target);
|
|
}
|
|
|
|
// Visit the loop body itself.
|
|
VarDecl *bodyVar = visit(forEachStmt->getBody());
|
|
if (!bodyVar)
|
|
return nullptr;
|
|
|
|
// If there's no constraint system, there is nothing left to visit.
|
|
if (!cs)
|
|
return nullptr;
|
|
|
|
// Form a variable of array type that will capture the result of each
|
|
// iteration of the loop. We need a fresh type variable to remove the
|
|
// lvalue-ness of the array variable.
|
|
SourceLoc loc = forEachStmt->getForLoc();
|
|
VarDecl *arrayVar = builder.buildVar(loc);
|
|
Type arrayElementType = cs->createTypeVariable(
|
|
cs->getConstraintLocator(forEachStmt), 0);
|
|
cs->addConstraint(ConstraintKind::Equal, cs->getType(bodyVar),
|
|
arrayElementType,
|
|
cs->getConstraintLocator(
|
|
forEachStmt, ConstraintLocator::SequenceElementType));
|
|
Type arrayType = ArraySliceType::get(arrayElementType);
|
|
cs->setType(arrayVar, arrayType);
|
|
|
|
// Form an initialization of the array to an empty array literal.
|
|
Expr *arrayInitExpr = ArrayExpr::create(ctx, loc, { }, { }, loc);
|
|
cs->setContextualType(
|
|
arrayInitExpr, TypeLoc::withoutLoc(arrayType), CTP_CannotFail);
|
|
arrayInitExpr = cs->generateConstraints(arrayInitExpr, dc);
|
|
if (!arrayInitExpr) {
|
|
hadError = true;
|
|
return nullptr;
|
|
}
|
|
cs->addConstraint(
|
|
ConstraintKind::Equal, cs->getType(arrayInitExpr), arrayType,
|
|
cs->getConstraintLocator(
|
|
arrayInitExpr, LocatorPathElt::ContextualType(CTP_Initialization)));
|
|
|
|
// Form a call to Array.append(_:) to add the result of executing each
|
|
// iteration of the loop body to the array formed above.
|
|
SourceLoc endLoc = forEachStmt->getEndLoc();
|
|
auto arrayVarRef = builder.buildVarRef(arrayVar, endLoc);
|
|
auto arrayAppendRef = new (ctx) UnresolvedDotExpr(
|
|
arrayVarRef, endLoc, DeclNameRef(ctx.getIdentifier("append")),
|
|
DeclNameLoc(endLoc), /*implicit=*/true);
|
|
arrayAppendRef->setFunctionRefKind(FunctionRefKind::SingleApply);
|
|
|
|
auto bodyVarRef = builder.buildVarRef(bodyVar, endLoc);
|
|
auto *argList = ArgumentList::createImplicit(
|
|
ctx, endLoc, {Argument::unlabeled(bodyVarRef)}, endLoc);
|
|
Expr *arrayAppendCall =
|
|
CallExpr::createImplicit(ctx, arrayAppendRef, argList);
|
|
arrayAppendCall = cs->generateConstraints(arrayAppendCall, dc);
|
|
if (!arrayAppendCall) {
|
|
hadError = true;
|
|
return nullptr;
|
|
}
|
|
|
|
// Form the final call to buildArray(arrayVar) to allow the function
|
|
// builder to reshape the array into whatever it wants as the result of
|
|
// the for-each loop.
|
|
auto finalArrayVarRef = builder.buildVarRef(arrayVar, endLoc);
|
|
auto buildArrayCall = buildCallIfWanted(
|
|
endLoc, ctx.Id_buildArray, { finalArrayVarRef }, { Identifier() });
|
|
assert(buildArrayCall);
|
|
buildArrayCall = cs->generateConstraints(buildArrayCall, dc);
|
|
if (!buildArrayCall) {
|
|
hadError = true;
|
|
return nullptr;
|
|
}
|
|
|
|
// Form a final variable for the for-each expression itself, which will
|
|
// be initialized with the call to the result builder's buildArray(_:).
|
|
auto finalForEachVar = builder.buildVar(loc);
|
|
cs->setType(finalForEachVar, cs->getType(buildArrayCall));
|
|
applied.capturedStmts.insert(
|
|
{forEachStmt, {
|
|
finalForEachVar,
|
|
{ arrayVarRef, arrayInitExpr, arrayAppendCall, buildArrayCall }}});
|
|
|
|
return finalForEachVar;
|
|
}
|
|
|
|
/// Visit a throw statement, which never produces a result.
|
|
VarDecl *visitThrowStmt(ThrowStmt *throwStmt) {
|
|
if (!ctx.getErrorDecl()) {
|
|
hadError = true;
|
|
}
|
|
|
|
if (cs) {
|
|
SyntacticElementTarget target(throwStmt->getSubExpr(), dc, CTP_ThrowStmt,
|
|
ctx.getErrorExistentialType(),
|
|
/*isDiscarded=*/false);
|
|
if (cs->generateConstraints(target))
|
|
hadError = true;
|
|
|
|
cs->setTargetFor(throwStmt, target);
|
|
}
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
CONTROL_FLOW_STMT(Guard)
|
|
CONTROL_FLOW_STMT(While)
|
|
CONTROL_FLOW_STMT(DoCatch)
|
|
CONTROL_FLOW_STMT(RepeatWhile)
|
|
CONTROL_FLOW_STMT(Case)
|
|
CONTROL_FLOW_STMT(Break)
|
|
CONTROL_FLOW_STMT(Continue)
|
|
CONTROL_FLOW_STMT(Fallthrough)
|
|
CONTROL_FLOW_STMT(Fail)
|
|
CONTROL_FLOW_STMT(PoundAssert)
|
|
CONTROL_FLOW_STMT(Return)
|
|
|
|
#undef CONTROL_FLOW_STMT
|
|
};
|
|
|
|
class ResultBuilderTransform
|
|
: private BuilderTransformerBase,
|
|
private StmtVisitor<ResultBuilderTransform, NullablePtr<Stmt>,
|
|
NullablePtr<VarDecl>> {
|
|
friend StmtVisitor<ResultBuilderTransform, NullablePtr<Stmt>,
|
|
NullablePtr<VarDecl>>;
|
|
|
|
using UnsupportedElt = SkipUnhandledConstructInResultBuilder::UnhandledNode;
|
|
|
|
/// The result type of this result builder body.
|
|
Type ResultType;
|
|
|
|
/// The first recorded unsupported element discovered by the transformation.
|
|
UnsupportedElt FirstUnsupported;
|
|
|
|
public:
|
|
ResultBuilderTransform(ConstraintSystem &cs, DeclContext *dc,
|
|
Type builderType, Type resultTy)
|
|
: BuilderTransformerBase(&cs, dc, builderType), ResultType(resultTy) {}
|
|
|
|
UnsupportedElt getUnsupportedElement() const { return FirstUnsupported; }
|
|
|
|
BraceStmt *apply(BraceStmt *braceStmt) {
|
|
auto newBody = visitBraceStmt(braceStmt, /*bodyVar=*/nullptr);
|
|
if (!newBody)
|
|
return nullptr;
|
|
return castToStmt<BraceStmt>(newBody.get());
|
|
}
|
|
|
|
VarDecl *getBuilderSelf() const { return builder.getBuilderSelf(); }
|
|
|
|
protected:
|
|
NullablePtr<Stmt> failTransform(UnsupportedElt unsupported) {
|
|
recordUnsupported(unsupported);
|
|
return nullptr;
|
|
}
|
|
|
|
Expr *buildCallIfWanted(SourceLoc loc, Identifier fnName,
|
|
ArrayRef<Expr *> argExprs,
|
|
ArrayRef<Identifier> argLabels) override {
|
|
return builder.buildCall(loc, fnName, argExprs, argLabels);
|
|
}
|
|
|
|
VarDecl *recordVar(PatternBindingDecl *PB,
|
|
SmallVectorImpl<ASTNode> &container) {
|
|
container.push_back(PB);
|
|
container.push_back(PB->getSingleVar());
|
|
return PB->getSingleVar();
|
|
}
|
|
|
|
VarDecl *captureExpr(Expr *expr, SmallVectorImpl<ASTNode> &container) {
|
|
auto *var = builder.buildVar(expr->getStartLoc());
|
|
Pattern *pattern = NamedPattern::createImplicit(ctx, var);
|
|
auto *PB = PatternBindingDecl::createImplicit(
|
|
ctx, StaticSpellingKind::None, pattern, expr, dc, var->getStartLoc());
|
|
return recordVar(PB, container);
|
|
}
|
|
|
|
VarDecl *buildPlaceholderVar(SourceLoc loc,
|
|
SmallVectorImpl<ASTNode> &container,
|
|
Type type = Type(), Expr *initExpr = nullptr) {
|
|
auto *var = builder.buildVar(loc);
|
|
Pattern *placeholder = TypedPattern::createImplicit(
|
|
ctx, NamedPattern::createImplicit(ctx, var),
|
|
type ? type : PlaceholderType::get(ctx, var));
|
|
auto *PB = PatternBindingDecl::createImplicit(
|
|
ctx, StaticSpellingKind::None, placeholder, /*init=*/initExpr, dc,
|
|
var->getStartLoc());
|
|
return recordVar(PB, container);
|
|
}
|
|
|
|
AssignExpr *buildAssignment(VarDecl *dst, VarDecl *src) {
|
|
auto *dstRef = builder.buildVarRef(dst, /*Loc=*/SourceLoc());
|
|
auto *srcRef = builder.buildVarRef(src, /*Loc=*/SourceLoc());
|
|
return new (ctx) AssignExpr(dstRef, /*EqualLoc=*/SourceLoc(), srcRef,
|
|
/*Implicit=*/true);
|
|
}
|
|
|
|
AssignExpr *buildAssignment(VarDecl *dst, Expr *srcExpr) {
|
|
auto *dstRef = builder.buildVarRef(dst, /*Loc=*/SourceLoc());
|
|
return new (ctx) AssignExpr(dstRef, /*EqualLoc=*/SourceLoc(), srcExpr,
|
|
/*implicit=*/true);
|
|
}
|
|
|
|
void recordUnsupported(UnsupportedElt node) {
|
|
if (!FirstUnsupported)
|
|
FirstUnsupported = node;
|
|
}
|
|
|
|
#define UNSUPPORTED_STMT(StmtClass) \
|
|
NullablePtr<Stmt> visit##StmtClass##Stmt(StmtClass##Stmt *stmt, \
|
|
NullablePtr<VarDecl> var) { \
|
|
return failTransform(stmt); \
|
|
}
|
|
|
|
/// Visit the element of a brace statement, returning \c None if the element
|
|
/// was transformed successfully, or an unsupported element if the element
|
|
/// cannot be handled.
|
|
Optional<UnsupportedElt>
|
|
transformBraceElement(ASTNode element, SmallVectorImpl<ASTNode> &newBody,
|
|
SmallVectorImpl<Expr *> &buildBlockArguments) {
|
|
if (auto *returnStmt = getAsStmt<ReturnStmt>(element)) {
|
|
assert(returnStmt->isImplicit());
|
|
element = returnStmt->getResult();
|
|
}
|
|
|
|
if (auto *decl = element.dyn_cast<Decl *>()) {
|
|
switch (decl->getKind()) {
|
|
// Just ignore #if; the chosen children should appear in
|
|
// the surrounding context. This isn't good for source
|
|
// tools but it at least works.
|
|
case DeclKind::IfConfig:
|
|
// Skip #warning/#error; we'll handle them when applying
|
|
// the builder.
|
|
case DeclKind::PoundDiagnostic:
|
|
case DeclKind::PatternBinding:
|
|
case DeclKind::Var:
|
|
case DeclKind::Param:
|
|
newBody.push_back(element);
|
|
return None;
|
|
|
|
default:
|
|
return UnsupportedElt(decl);
|
|
}
|
|
llvm_unreachable("Unhandled case in switch!");
|
|
}
|
|
|
|
if (auto *stmt = element.dyn_cast<Stmt *>()) {
|
|
// Throw is allowed as is.
|
|
if (auto *throwStmt = dyn_cast<ThrowStmt>(stmt)) {
|
|
newBody.push_back(throwStmt);
|
|
return None;
|
|
}
|
|
|
|
// Allocate variable with a placeholder type
|
|
auto *resultVar = buildPlaceholderVar(stmt->getStartLoc(), newBody);
|
|
|
|
auto result = visit(stmt, resultVar);
|
|
if (!result)
|
|
return UnsupportedElt(stmt);
|
|
|
|
newBody.push_back(result.get());
|
|
buildBlockArguments.push_back(
|
|
builder.buildVarRef(resultVar, stmt->getStartLoc()));
|
|
return None;
|
|
}
|
|
|
|
auto *expr = element.get<Expr *>();
|
|
if (auto *SVE = dyn_cast<SingleValueStmtExpr>(expr)) {
|
|
// This should never be treated as an expression in a result builder, it
|
|
// should have statement semantics.
|
|
return transformBraceElement(SVE->getStmt(), newBody,
|
|
buildBlockArguments);
|
|
}
|
|
if (builder.supports(ctx.Id_buildExpression)) {
|
|
expr = builder.buildCall(expr->getLoc(), ctx.Id_buildExpression, {expr},
|
|
{Identifier()});
|
|
}
|
|
|
|
if (isa<CodeCompletionExpr>(expr)) {
|
|
// Insert the CodeCompletionExpr directly into the buildBlock call. That
|
|
// way, we can extract the contextual type of the code completion token
|
|
// to rank code completion items that match the type expected by
|
|
// buildBlock higher.
|
|
buildBlockArguments.push_back(expr);
|
|
} else {
|
|
auto *capture = captureExpr(expr, newBody);
|
|
// A reference to the synthesized variable is passed as an argument
|
|
// to buildBlock.
|
|
buildBlockArguments.push_back(
|
|
builder.buildVarRef(capture, element.getStartLoc()));
|
|
}
|
|
|
|
return None;
|
|
}
|
|
|
|
std::pair<NullablePtr<Expr>, Optional<UnsupportedElt>>
|
|
transform(BraceStmt *braceStmt, SmallVectorImpl<ASTNode> &newBody) {
|
|
SmallVector<Expr *, 4> buildBlockArguments;
|
|
|
|
auto failTransform = [&](UnsupportedElt unsupported) {
|
|
return std::make_pair(nullptr, unsupported);
|
|
};
|
|
|
|
for (auto element : braceStmt->getElements()) {
|
|
if (auto unsupported =
|
|
transformBraceElement(element, newBody, buildBlockArguments)) {
|
|
return failTransform(*unsupported);
|
|
}
|
|
}
|
|
|
|
// Synthesize `buildBlock` or `buildPartial` based on captured arguments.
|
|
{
|
|
// If the builder supports `buildPartialBlock(first:)` and
|
|
// `buildPartialBlock(accumulated:next:)`, use this to combine
|
|
// sub-expressions pairwise.
|
|
if (!buildBlockArguments.empty() && builder.canUseBuildPartialBlock()) {
|
|
// let v0 = Builder.buildPartialBlock(first: arg_0)
|
|
// let v1 = Builder.buildPartialBlock(accumulated: v0, next: arg_1)
|
|
// ...
|
|
// let vN = Builder.buildPartialBlock(accumulated: vN-1, next: argN)
|
|
auto *buildPartialFirst = builder.buildCall(
|
|
braceStmt->getStartLoc(), ctx.Id_buildPartialBlock,
|
|
{buildBlockArguments.front()},
|
|
/*argLabels=*/{ctx.Id_first});
|
|
|
|
auto *buildBlockVar = captureExpr(buildPartialFirst, newBody);
|
|
|
|
for (auto *argExpr : llvm::drop_begin(buildBlockArguments)) {
|
|
auto *accumPartialBlock = builder.buildCall(
|
|
braceStmt->getStartLoc(), ctx.Id_buildPartialBlock,
|
|
{builder.buildVarRef(buildBlockVar, argExpr->getStartLoc()),
|
|
argExpr},
|
|
{ctx.Id_accumulated, ctx.Id_next});
|
|
buildBlockVar = captureExpr(accumPartialBlock, newBody);
|
|
}
|
|
|
|
return std::make_pair(
|
|
builder.buildVarRef(buildBlockVar, braceStmt->getStartLoc()), None);
|
|
}
|
|
// If `buildBlock` does not exist at this point, it could be the case that
|
|
// `buildPartialBlock` did not have the sufficient availability for this
|
|
// call site. Diagnose it.
|
|
else if (!builder.supports(ctx.Id_buildBlock)) {
|
|
ctx.Diags.diagnose(
|
|
braceStmt->getStartLoc(),
|
|
diag::result_builder_missing_available_buildpartialblock,
|
|
builder.getType());
|
|
return failTransform(braceStmt);
|
|
}
|
|
|
|
// Otherwise, call `buildBlock` on all subexpressions.
|
|
// Call Builder.buildBlock(... args ...)
|
|
auto *buildBlock = builder.buildCall(
|
|
braceStmt->getStartLoc(), ctx.Id_buildBlock, buildBlockArguments,
|
|
/*argLabels=*/{});
|
|
return std::make_pair(buildBlock, None);
|
|
}
|
|
}
|
|
|
|
std::pair<bool, UnsupportedElt>
|
|
transform(BraceStmt *braceStmt, NullablePtr<VarDecl> bodyVar,
|
|
SmallVectorImpl<ASTNode> &elements) {
|
|
// Arguments passed to a synthesized `build{Partial}Block`.
|
|
SmallVector<Expr *, 4> buildBlockArguments;
|
|
|
|
auto failure = [&](UnsupportedElt element) {
|
|
return std::make_pair(true, element);
|
|
};
|
|
|
|
NullablePtr<Expr> buildBlockVarRef;
|
|
Optional<UnsupportedElt> unsupported;
|
|
|
|
std::tie(buildBlockVarRef, unsupported) = transform(braceStmt, elements);
|
|
if (unsupported)
|
|
return failure(*unsupported);
|
|
|
|
// If this is not a top-level brace statement, we need to form an
|
|
// assignment from the `build{Partial}Block` call result variable
|
|
// to the provided one.
|
|
//
|
|
// Use start loc for the return statement so any contextual issues
|
|
// are attached to the beginning of the brace instead of its end.
|
|
auto resultLoc = braceStmt->getStartLoc();
|
|
if (bodyVar) {
|
|
elements.push_back(
|
|
new (ctx) AssignExpr(builder.buildVarRef(bodyVar.get(), resultLoc),
|
|
/*EqualLoc=*/SourceLoc(), buildBlockVarRef.get(),
|
|
/*Implicit=*/true));
|
|
} else {
|
|
Expr *buildBlockResult = buildBlockVarRef.get();
|
|
// Otherwise, it's a top-level brace and we need to synthesize
|
|
// a call to `buildFialBlock` if supported.
|
|
if (builder.supports(ctx.Id_buildFinalResult, {Identifier()})) {
|
|
buildBlockResult =
|
|
builder.buildCall(resultLoc, ctx.Id_buildFinalResult,
|
|
{buildBlockResult}, {Identifier()});
|
|
}
|
|
|
|
elements.push_back(new (ctx) ReturnStmt(resultLoc, buildBlockResult,
|
|
/*Implicit=*/true));
|
|
}
|
|
|
|
return std::make_pair(false, UnsupportedElt());
|
|
}
|
|
|
|
BraceStmt *cloneBraceWith(BraceStmt *braceStmt,
|
|
SmallVectorImpl<ASTNode> &elements) {
|
|
auto lBrace = braceStmt ? braceStmt->getLBraceLoc() : SourceLoc();
|
|
auto rBrace = braceStmt ? braceStmt->getRBraceLoc() : SourceLoc();
|
|
bool implicit = braceStmt ? braceStmt->isImplicit() : true;
|
|
|
|
return BraceStmt::create(ctx, lBrace, elements, rBrace, implicit);
|
|
}
|
|
|
|
NullablePtr<Stmt> visitBraceStmt(BraceStmt *braceStmt,
|
|
NullablePtr<VarDecl> bodyVar) {
|
|
SmallVector<ASTNode, 4> elements;
|
|
|
|
bool failed;
|
|
UnsupportedElt unsupported;
|
|
|
|
std::tie(failed, unsupported) = transform(braceStmt, bodyVar, elements);
|
|
|
|
if (failed)
|
|
return failTransform(unsupported);
|
|
|
|
return cloneBraceWith(braceStmt, elements);
|
|
}
|
|
|
|
NullablePtr<Stmt> visitDoStmt(DoStmt *doStmt, NullablePtr<VarDecl> doVar) {
|
|
auto body = visitBraceStmt(doStmt->getBody(), doVar);
|
|
if (!body)
|
|
return nullptr;
|
|
|
|
return new (ctx) DoStmt(doStmt->getLabelInfo(), doStmt->getDoLoc(),
|
|
cast<BraceStmt>(body.get()), doStmt->isImplicit());
|
|
}
|
|
|
|
NullablePtr<Stmt> visitIfStmt(IfStmt *ifStmt, NullablePtr<VarDecl> ifVar) {
|
|
// Check whether the chain is buildable and whether it terminates
|
|
// without an `else`.
|
|
bool isOptional = false;
|
|
unsigned numPayloads = 0;
|
|
if (!isBuildableIfChain(ifStmt, numPayloads, isOptional))
|
|
return failTransform(ifStmt);
|
|
|
|
SmallVector<std::pair<Expr *, Stmt *>, 4> branchVarRefs;
|
|
|
|
auto transformed = transformIf(ifStmt, branchVarRefs);
|
|
if (!transformed)
|
|
return failTransform(ifStmt);
|
|
|
|
// Let's wrap `if` statement into a `do` and inject `type-join`
|
|
// operation with appropriate combination of `buildEither` that
|
|
// would get re-distributed after inference.
|
|
SmallVector<ASTNode, 4> doBody;
|
|
{
|
|
ifStmt = transformed.get();
|
|
|
|
// `if` goes first.
|
|
doBody.push_back(ifStmt);
|
|
|
|
assert(numPayloads == branchVarRefs.size());
|
|
|
|
SmallVector<Expr *, 4> buildEitherCalls;
|
|
for (unsigned i = 0; i != numPayloads; i++) {
|
|
Expr *branchVarRef;
|
|
Stmt *anchor;
|
|
|
|
std::tie(branchVarRef, anchor) = branchVarRefs[i];
|
|
|
|
auto *builderCall =
|
|
buildWrappedChainPayload(branchVarRef, i, numPayloads, isOptional);
|
|
|
|
// The operand should have optional type if we had optional results,
|
|
// so we just need to call `buildIf` now, since we're at the top level.
|
|
if (isOptional) {
|
|
builderCall = buildCallIfWanted(ifStmt->getThenStmt()->getStartLoc(),
|
|
builder.getBuildOptionalId(),
|
|
builderCall, /*argLabels=*/{});
|
|
}
|
|
|
|
buildEitherCalls.push_back(builderCall);
|
|
}
|
|
|
|
// If there is no `else` branch we need to build one.
|
|
// It consists a `buildOptional` call that uses `nil` as an argument.
|
|
//
|
|
// ```
|
|
// {
|
|
// $__builderResult = buildOptional(nil)
|
|
// }
|
|
// ```
|
|
//
|
|
// Type of `nil` is going to be inferred from `$__builderResult`.
|
|
if (!hasUnconditionalElse(ifStmt)) {
|
|
assert(isOptional);
|
|
|
|
auto *nil =
|
|
new (ctx) NilLiteralExpr(ifStmt->getEndLoc(), /*implicit=*/true);
|
|
|
|
buildEitherCalls.push_back(buildCallIfWanted(
|
|
/*loc=*/ifStmt->getEndLoc(), builder.getBuildOptionalId(), nil,
|
|
/*argLabels=*/{}));
|
|
}
|
|
|
|
auto *ifVarRef = builder.buildVarRef(ifVar.get(), ifStmt->getStartLoc());
|
|
doBody.push_back(TypeJoinExpr::create(ctx, ifVarRef, buildEitherCalls));
|
|
}
|
|
|
|
return DoStmt::createImplicit(ctx, LabeledStmtInfo(), doBody);
|
|
}
|
|
|
|
NullablePtr<IfStmt>
|
|
transformIf(IfStmt *ifStmt,
|
|
SmallVectorImpl<std::pair<Expr *, Stmt *>> &branchVarRefs) {
|
|
Optional<UnsupportedElt> unsupported;
|
|
|
|
// If there is a #available in the condition, wrap the 'then' or 'else'
|
|
// in a call to buildLimitedAvailability(_:).
|
|
auto availabilityCond = findAvailabilityCondition(ifStmt->getCond());
|
|
bool supportsAvailability =
|
|
availabilityCond && builder.supports(ctx.Id_buildLimitedAvailability);
|
|
|
|
NullablePtr<Expr> thenVarRef;
|
|
NullablePtr<Stmt> thenBranch;
|
|
{
|
|
SmallVector<ASTNode, 4> thenBody;
|
|
|
|
auto *ifBraceStmt = cast<BraceStmt>(ifStmt->getThenStmt());
|
|
|
|
std::tie(thenVarRef, unsupported) = transform(ifBraceStmt, thenBody);
|
|
if (unsupported) {
|
|
recordUnsupported(*unsupported);
|
|
return nullptr;
|
|
}
|
|
|
|
if (supportsAvailability &&
|
|
!availabilityCond->getAvailability()->isUnavailability()) {
|
|
auto *builderCall = buildCallIfWanted(
|
|
ifBraceStmt->getStartLoc(), ctx.Id_buildLimitedAvailability,
|
|
{thenVarRef.get()}, {Identifier()});
|
|
|
|
thenVarRef = builder.buildVarRef(captureExpr(builderCall, thenBody),
|
|
ifBraceStmt->getStartLoc());
|
|
}
|
|
|
|
thenBranch = cloneBraceWith(ifBraceStmt, thenBody);
|
|
branchVarRefs.push_back({thenVarRef.get(), thenBranch.get()});
|
|
}
|
|
|
|
NullablePtr<Stmt> elseBranch;
|
|
|
|
if (auto *elseStmt = ifStmt->getElseStmt()) {
|
|
NullablePtr<Expr> elseVarRef;
|
|
|
|
if (auto *innerIfStmt = getAsStmt<IfStmt>(elseStmt)) {
|
|
elseBranch = transformIf(innerIfStmt, branchVarRefs);
|
|
if (!elseBranch) {
|
|
recordUnsupported(innerIfStmt);
|
|
return nullptr;
|
|
}
|
|
} else {
|
|
auto *elseBraceStmt = cast<BraceStmt>(elseStmt);
|
|
SmallVector<ASTNode> elseBody;
|
|
|
|
std::tie(elseVarRef, unsupported) = transform(elseBraceStmt, elseBody);
|
|
if (unsupported) {
|
|
recordUnsupported(*unsupported);
|
|
return nullptr;
|
|
}
|
|
|
|
// If there is a #unavailable in the condition, wrap the 'else' in a
|
|
// call to buildLimitedAvailability(_:).
|
|
if (supportsAvailability &&
|
|
availabilityCond->getAvailability()->isUnavailability()) {
|
|
auto *builderCall = buildCallIfWanted(
|
|
elseBraceStmt->getStartLoc(), ctx.Id_buildLimitedAvailability,
|
|
{elseVarRef.get()}, {Identifier()});
|
|
|
|
elseVarRef = builder.buildVarRef(captureExpr(builderCall, elseBody),
|
|
elseBraceStmt->getStartLoc());
|
|
}
|
|
|
|
elseBranch = cloneBraceWith(elseBraceStmt, elseBody);
|
|
branchVarRefs.push_back({elseVarRef.get(), elseBranch.get()});
|
|
}
|
|
}
|
|
|
|
return new (ctx)
|
|
IfStmt(ifStmt->getLabelInfo(), ifStmt->getIfLoc(), ifStmt->getCond(),
|
|
thenBranch.get(), ifStmt->getElseLoc(),
|
|
elseBranch.getPtrOrNull(), ifStmt->isImplicit());
|
|
}
|
|
|
|
NullablePtr<Stmt> visitSwitchStmt(SwitchStmt *switchStmt,
|
|
NullablePtr<VarDecl> switchVar) {
|
|
// For a do statement wrapping this switch that contains all of the
|
|
// `buildEither` calls that would get injected back into `case` bodies
|
|
// after solving is done.
|
|
//
|
|
// This is necessary because `buildEither requires type information from
|
|
// both sides to be available, so all case statements have to be
|
|
// type-checked first.
|
|
SmallVector<ASTNode, 4> doBody;
|
|
|
|
SmallVector<ASTNode, 4> cases;
|
|
SmallVector<Expr *, 4> caseVarRefs;
|
|
|
|
for (auto *caseStmt : switchStmt->getCases()) {
|
|
auto transformed = transformCase(caseStmt);
|
|
if (!transformed)
|
|
return failTransform(caseStmt);
|
|
|
|
cases.push_back(transformed->second);
|
|
caseVarRefs.push_back(transformed->first);
|
|
}
|
|
|
|
// If there are no 'case' statements in the body let's try
|
|
// to diagnose this situation via limited exhaustiveness check
|
|
// before failing a builder transform, otherwise type-checker
|
|
// might end up without any diagnostics which leads to crashes
|
|
// in SILGen.
|
|
if (caseVarRefs.empty()) {
|
|
TypeChecker::checkSwitchExhaustiveness(switchStmt, dc,
|
|
/*limitChecking=*/true);
|
|
return failTransform(switchStmt);
|
|
}
|
|
|
|
auto *transformedSwitch = SwitchStmt::create(
|
|
switchStmt->getLabelInfo(), switchStmt->getSwitchLoc(),
|
|
switchStmt->getSubjectExpr(), switchStmt->getLBraceLoc(), cases,
|
|
switchStmt->getRBraceLoc(), switchStmt->getEndLoc(), ctx);
|
|
|
|
doBody.push_back(transformedSwitch);
|
|
|
|
SmallVector<Expr *, 4> injectedExprs;
|
|
for (auto idx : indices(caseVarRefs)) {
|
|
auto *caseVarRef = caseVarRefs[idx];
|
|
|
|
// Build the expression that injects the case variable into appropriate
|
|
// buildEither(first:)/buildEither(second:) chain.
|
|
Expr *injectedCaseExpr = buildWrappedChainPayload(
|
|
caseVarRef, idx, caseVarRefs.size(), /*isOptional=*/false);
|
|
|
|
injectedExprs.push_back(injectedCaseExpr);
|
|
}
|
|
|
|
auto *switchVarRef =
|
|
builder.buildVarRef(switchVar.get(), switchStmt->getEndLoc());
|
|
doBody.push_back(TypeJoinExpr::create(ctx, switchVarRef, injectedExprs));
|
|
|
|
return DoStmt::createImplicit(ctx, LabeledStmtInfo(), doBody);
|
|
}
|
|
|
|
Optional<std::pair<Expr *, CaseStmt *>> transformCase(CaseStmt *caseStmt) {
|
|
auto *body = caseStmt->getBody();
|
|
|
|
// Explicitly disallow `case` statements with empty bodies
|
|
// since that helps to diagnose other issues with switch
|
|
// statements by excluding invalid cases.
|
|
if (auto *BS = dyn_cast<BraceStmt>(body)) {
|
|
if (BS->getNumElements() == 0) {
|
|
// HACK: still allow empty bodies if typechecking for code
|
|
// completion. Code completion ignores diagnostics
|
|
// and won't get any types if we fail.
|
|
if (!ctx.SourceMgr.hasIDEInspectionTargetBuffer())
|
|
return None;
|
|
}
|
|
}
|
|
|
|
NullablePtr<Expr> caseVarRef;
|
|
Optional<UnsupportedElt> unsupported;
|
|
SmallVector<ASTNode, 4> newBody;
|
|
|
|
std::tie(caseVarRef, unsupported) = transform(body, newBody);
|
|
|
|
if (unsupported) {
|
|
recordUnsupported(*unsupported);
|
|
return None;
|
|
}
|
|
|
|
auto *newCase = CaseStmt::create(
|
|
ctx, caseStmt->getParentKind(), caseStmt->getLoc(),
|
|
caseStmt->getCaseLabelItems(),
|
|
caseStmt->hasUnknownAttr() ? caseStmt->getStartLoc() : SourceLoc(),
|
|
caseStmt->getItemTerminatorLoc(), cloneBraceWith(body, newBody),
|
|
caseStmt->getCaseBodyVariablesOrEmptyArray(), caseStmt->isImplicit(),
|
|
caseStmt->getFallthroughStmt());
|
|
|
|
return std::make_pair(caseVarRef.get(), newCase);
|
|
}
|
|
|
|
/// do {
|
|
/// var $__forEach = []
|
|
/// for ... in ... {
|
|
/// ...
|
|
/// $__builderVar = buildBlock(...)
|
|
/// $__forEach.append($__builderVar)
|
|
/// }
|
|
/// buildArray($__forEach)
|
|
/// }
|
|
NullablePtr<Stmt> visitForEachStmt(ForEachStmt *forEachStmt,
|
|
NullablePtr<VarDecl> forEachVar) {
|
|
// for...in statements are handled via buildArray(_:); bail out if the
|
|
// builder does not support it.
|
|
if (!builder.supports(ctx.Id_buildArray))
|
|
return failTransform(forEachStmt);
|
|
|
|
// For-each statements require the Sequence protocol. If we don't have
|
|
// it (which generally means the standard library isn't loaded), fall
|
|
// out of the result-builder path entirely to let normal type checking
|
|
// take care of this.
|
|
auto sequenceProto = TypeChecker::getProtocol(
|
|
dc->getASTContext(), forEachStmt->getForLoc(),
|
|
forEachStmt->getAwaitLoc().isValid() ? KnownProtocolKind::AsyncSequence
|
|
: KnownProtocolKind::Sequence);
|
|
if (!sequenceProto)
|
|
return failTransform(forEachStmt);
|
|
|
|
SmallVector<ASTNode, 4> doBody;
|
|
SourceLoc endLoc = forEachStmt->getEndLoc();
|
|
|
|
// Build a variable that is going to hold array of results produced
|
|
// by each iteration of the loop.
|
|
//
|
|
// Not that it's not going to be initialized here, that would happen
|
|
// only when a solution is found.
|
|
VarDecl *arrayVar = buildPlaceholderVar(
|
|
forEachStmt->getEndLoc(), doBody,
|
|
ArraySliceType::get(PlaceholderType::get(ctx, forEachVar.get())),
|
|
ArrayExpr::create(ctx, /*LBrace=*/endLoc, /*Elements=*/{},
|
|
/*Commas=*/{}, /*RBrace=*/endLoc));
|
|
|
|
NullablePtr<Expr> bodyVarRef;
|
|
Optional<UnsupportedElt> unsupported;
|
|
|
|
SmallVector<ASTNode, 4> newBody;
|
|
{
|
|
std::tie(bodyVarRef, unsupported) =
|
|
transform(forEachStmt->getBody(), newBody);
|
|
if (unsupported)
|
|
return failTransform(*unsupported);
|
|
|
|
// Form a call to Array.append(_:) to add the result of executing each
|
|
// iteration of the loop body to the array formed above.
|
|
{
|
|
auto arrayVarRef = builder.buildVarRef(arrayVar, endLoc);
|
|
auto arrayAppendRef = new (ctx) UnresolvedDotExpr(
|
|
arrayVarRef, endLoc, DeclNameRef(ctx.getIdentifier("append")),
|
|
DeclNameLoc(endLoc), /*implicit=*/true);
|
|
arrayAppendRef->setFunctionRefKind(FunctionRefKind::SingleApply);
|
|
|
|
auto *argList = ArgumentList::createImplicit(
|
|
ctx, endLoc, {Argument::unlabeled(bodyVarRef.get())}, endLoc);
|
|
|
|
newBody.push_back(
|
|
CallExpr::createImplicit(ctx, arrayAppendRef, argList));
|
|
}
|
|
}
|
|
|
|
auto *newForEach = new (ctx)
|
|
ForEachStmt(forEachStmt->getLabelInfo(), forEachStmt->getForLoc(),
|
|
forEachStmt->getTryLoc(), forEachStmt->getAwaitLoc(),
|
|
forEachStmt->getPattern(), forEachStmt->getInLoc(),
|
|
forEachStmt->getParsedSequence(),
|
|
forEachStmt->getWhereLoc(), forEachStmt->getWhere(),
|
|
cloneBraceWith(forEachStmt->getBody(), newBody),
|
|
forEachStmt->isImplicit());
|
|
|
|
// For a body of new `do` statement that holds updated `for-in` loop
|
|
// and epilog that consists of a call to `buildArray` that forms the
|
|
// final result.
|
|
{
|
|
// Modified `for { ... }`
|
|
doBody.push_back(newForEach);
|
|
|
|
// $__forEach = buildArray($__arrayVar)
|
|
doBody.push_back(buildAssignment(
|
|
forEachVar.get(),
|
|
buildCallIfWanted(forEachStmt->getEndLoc(), ctx.Id_buildArray,
|
|
{builder.buildVarRef(arrayVar, endLoc)},
|
|
{Identifier()})));
|
|
}
|
|
|
|
return DoStmt::createImplicit(ctx, LabeledStmtInfo(), doBody);
|
|
}
|
|
|
|
UNSUPPORTED_STMT(Throw)
|
|
UNSUPPORTED_STMT(Return)
|
|
UNSUPPORTED_STMT(Yield)
|
|
UNSUPPORTED_STMT(Forget)
|
|
UNSUPPORTED_STMT(Defer)
|
|
UNSUPPORTED_STMT(Guard)
|
|
UNSUPPORTED_STMT(While)
|
|
UNSUPPORTED_STMT(DoCatch)
|
|
UNSUPPORTED_STMT(RepeatWhile)
|
|
UNSUPPORTED_STMT(Break)
|
|
UNSUPPORTED_STMT(Continue)
|
|
UNSUPPORTED_STMT(Fallthrough)
|
|
UNSUPPORTED_STMT(Fail)
|
|
UNSUPPORTED_STMT(PoundAssert)
|
|
UNSUPPORTED_STMT(Case)
|
|
|
|
#undef UNSUPPORTED_STMT
|
|
};
|
|
|
|
/// Describes the target into which the result of a particular statement in
|
|
/// a closure involving a result builder should be written.
|
|
struct ResultBuilderTarget {
|
|
enum Kind {
|
|
/// The resulting value is returned from the closure.
|
|
ReturnValue,
|
|
/// The temporary variable into which the result should be assigned.
|
|
TemporaryVar,
|
|
/// An expression to evaluate at the end of the block, allowing the update
|
|
/// of some state from an outer scope.
|
|
Expression,
|
|
} kind;
|
|
|
|
/// Captured variable information.
|
|
std::pair<VarDecl *, llvm::TinyPtrVector<Expr *>> captured;
|
|
|
|
static ResultBuilderTarget forReturn(Expr *expr) {
|
|
return ResultBuilderTarget{ReturnValue, {nullptr, {expr}}};
|
|
}
|
|
|
|
static ResultBuilderTarget forAssign(VarDecl *temporaryVar,
|
|
llvm::TinyPtrVector<Expr *> exprs) {
|
|
return ResultBuilderTarget{TemporaryVar, {temporaryVar, exprs}};
|
|
}
|
|
|
|
static ResultBuilderTarget forExpression(Expr *expr) {
|
|
return ResultBuilderTarget{Expression, { nullptr, { expr }}};
|
|
}
|
|
};
|
|
|
|
/// Handles the rewrite of the body of a closure to which a result builder
|
|
/// has been applied.
|
|
class BuilderClosureRewriter
|
|
: public StmtVisitor<BuilderClosureRewriter, NullablePtr<Stmt>,
|
|
ResultBuilderTarget> {
|
|
ASTContext &ctx;
|
|
const Solution &solution;
|
|
DeclContext *dc;
|
|
AppliedBuilderTransform builderTransform;
|
|
std::function<Optional<SyntacticElementTarget>(SyntacticElementTarget)>
|
|
rewriteTarget;
|
|
|
|
/// Retrieve the temporary variable that will be used to capture the
|
|
/// value of the given expression.
|
|
AppliedBuilderTransform::RecordedExpr takeCapturedExpr(Expr *expr) {
|
|
auto found = builderTransform.capturedExprs.find(expr);
|
|
assert(found != builderTransform.capturedExprs.end());
|
|
|
|
// Set the type of the temporary variable.
|
|
auto recorded = found->second;
|
|
if (auto temporaryVar = recorded.temporaryVar) {
|
|
Type type = solution.simplifyType(solution.getType(temporaryVar));
|
|
temporaryVar->setInterfaceType(type->mapTypeOutOfContext());
|
|
}
|
|
|
|
// Erase the captured expression, so we're sure we never do this twice.
|
|
builderTransform.capturedExprs.erase(found);
|
|
return recorded;
|
|
}
|
|
|
|
/// Rewrite an expression without any particularly special context.
|
|
Expr *rewriteExpr(Expr *expr) {
|
|
auto result =
|
|
rewriteTarget(SyntacticElementTarget(expr, dc, CTP_Unused, Type(),
|
|
/*isDiscarded=*/false));
|
|
if (result)
|
|
return result->getAsExpr();
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
public:
|
|
/// Retrieve information about a captured statement.
|
|
std::pair<VarDecl *, llvm::TinyPtrVector<Expr *>>
|
|
takeCapturedStmt(Stmt *stmt) {
|
|
auto found = builderTransform.capturedStmts.find(stmt);
|
|
assert(found != builderTransform.capturedStmts.end());
|
|
|
|
// Set the type of the temporary variable.
|
|
auto temporaryVar = found->second.first;
|
|
Type type = solution.simplifyType(solution.getType(temporaryVar));
|
|
temporaryVar->setInterfaceType(type->mapTypeOutOfContext());
|
|
|
|
// Take the expressions.
|
|
auto exprs = std::move(found->second.second);
|
|
|
|
// Erase the statement, so we're sure we never do this twice.
|
|
builderTransform.capturedStmts.erase(found);
|
|
return std::make_pair(temporaryVar, std::move(exprs));
|
|
}
|
|
|
|
private:
|
|
/// Build the statement or expression to initialize the target.
|
|
ASTNode initializeTarget(ResultBuilderTarget target) {
|
|
assert(target.captured.second.size() == 1);
|
|
auto capturedExpr = target.captured.second.front();
|
|
SourceLoc implicitLoc = capturedExpr->getEndLoc();
|
|
switch (target.kind) {
|
|
case ResultBuilderTarget::ReturnValue: {
|
|
// Return the expression.
|
|
Type bodyResultInterfaceType =
|
|
solution.simplifyType(builderTransform.bodyResultType);
|
|
|
|
SyntacticElementTarget returnTarget(capturedExpr, dc, CTP_ReturnStmt,
|
|
bodyResultInterfaceType,
|
|
/*isDiscarded=*/false);
|
|
Expr *resultExpr = nullptr;
|
|
if (auto resultTarget = rewriteTarget(returnTarget))
|
|
resultExpr = resultTarget->getAsExpr();
|
|
|
|
return new (ctx) ReturnStmt(implicitLoc, resultExpr);
|
|
}
|
|
|
|
case ResultBuilderTarget::TemporaryVar: {
|
|
// Assign the expression into a variable.
|
|
auto temporaryVar = target.captured.first;
|
|
auto declRef = new (ctx) DeclRefExpr(
|
|
temporaryVar, DeclNameLoc(implicitLoc), /*implicit=*/true);
|
|
declRef->setType(LValueType::get(temporaryVar->getType()));
|
|
|
|
// Load the right-hand side if needed.
|
|
auto finalCapturedExpr = rewriteExpr(capturedExpr);
|
|
if (finalCapturedExpr->getType()->hasLValueType()) {
|
|
finalCapturedExpr =
|
|
TypeChecker::addImplicitLoadExpr(ctx, finalCapturedExpr);
|
|
}
|
|
|
|
auto assign = new (ctx) AssignExpr(
|
|
declRef, implicitLoc, finalCapturedExpr, /*implicit=*/true);
|
|
assign->setType(TupleType::getEmpty(ctx));
|
|
return assign;
|
|
}
|
|
|
|
case ResultBuilderTarget::Expression:
|
|
// Execute the expression.
|
|
return rewriteExpr(capturedExpr);
|
|
}
|
|
llvm_unreachable("invalid result builder target");
|
|
}
|
|
|
|
/// Declare the given temporary variable, adding the appropriate
|
|
/// entries to the elements of a brace stmt.
|
|
void declareTemporaryVariable(VarDecl *temporaryVar,
|
|
std::vector<ASTNode> &elements,
|
|
Expr *initExpr = nullptr) {
|
|
if (!temporaryVar)
|
|
return;
|
|
|
|
// Form a new pattern binding to bind the temporary variable to the
|
|
// transformed expression.
|
|
auto pattern = NamedPattern::createImplicit(ctx, temporaryVar);
|
|
pattern->setType(temporaryVar->getType());
|
|
|
|
auto pbd = PatternBindingDecl::create(
|
|
ctx, SourceLoc(), StaticSpellingKind::None, temporaryVar->getLoc(),
|
|
pattern, SourceLoc(), initExpr, dc);
|
|
if (temporaryVar->isImplicit())
|
|
pbd->setImplicit();
|
|
elements.push_back(temporaryVar);
|
|
elements.push_back(pbd);
|
|
}
|
|
|
|
public:
|
|
BuilderClosureRewriter(
|
|
const Solution &solution, DeclContext *dc,
|
|
const AppliedBuilderTransform &builderTransform,
|
|
std::function<Optional<SyntacticElementTarget>(SyntacticElementTarget)>
|
|
rewriteTarget)
|
|
: ctx(solution.getConstraintSystem().getASTContext()), solution(solution),
|
|
dc(dc), builderTransform(builderTransform),
|
|
rewriteTarget(rewriteTarget) {}
|
|
|
|
/// Visit the element of a brace statement, returning \c false if the element
|
|
/// was rewritten successfully, or \c true if there was an error.
|
|
bool visitBraceElement(ASTNode node, std::vector<ASTNode> &newElements) {
|
|
// Implicit returns in single-expression function bodies are treated
|
|
// as the expression.
|
|
if (auto returnStmt =
|
|
dyn_cast_or_null<ReturnStmt>(node.dyn_cast<Stmt *>())) {
|
|
assert(returnStmt->isImplicit());
|
|
node = returnStmt->getResult();
|
|
}
|
|
|
|
if (auto expr = node.dyn_cast<Expr *>()) {
|
|
if (auto *SVE = dyn_cast<SingleValueStmtExpr>(expr)) {
|
|
// This should never be treated as an expression in a result builder, it
|
|
// should have statement semantics.
|
|
return visitBraceElement(SVE->getStmt(), newElements);
|
|
}
|
|
// Skip error expressions.
|
|
if (isa<ErrorExpr>(expr))
|
|
return false;
|
|
|
|
// Each expression turns into a 'let' that captures the value of
|
|
// the expression.
|
|
auto recorded = takeCapturedExpr(expr);
|
|
|
|
// Rewrite the expression
|
|
Expr *finalExpr = rewriteExpr(recorded.generatedExpr);
|
|
|
|
// Form a new pattern binding to bind the temporary variable to the
|
|
// transformed expression.
|
|
declareTemporaryVariable(recorded.temporaryVar, newElements, finalExpr);
|
|
return false;
|
|
}
|
|
|
|
if (auto stmt = node.dyn_cast<Stmt *>()) {
|
|
// "throw" statements produce no value. Transform them directly.
|
|
if (auto throwStmt = dyn_cast<ThrowStmt>(stmt)) {
|
|
if (auto newStmt = visitThrowStmt(throwStmt)) {
|
|
newElements.push_back(newStmt.get());
|
|
}
|
|
return false;
|
|
}
|
|
|
|
// Each statement turns into a (potential) temporary variable
|
|
// binding followed by the statement itself.
|
|
auto captured = takeCapturedStmt(stmt);
|
|
|
|
declareTemporaryVariable(captured.first, newElements);
|
|
|
|
auto finalStmt =
|
|
visit(stmt, ResultBuilderTarget{ResultBuilderTarget::TemporaryVar,
|
|
std::move(captured)});
|
|
|
|
// Re-write of statements that envolve type-checking
|
|
// could fail, such a failure terminates the walk.
|
|
if (!finalStmt)
|
|
return true;
|
|
|
|
newElements.push_back(finalStmt.get());
|
|
return false;
|
|
}
|
|
|
|
auto decl = node.get<Decl *>();
|
|
|
|
// Skip #if declarations.
|
|
if (isa<IfConfigDecl>(decl)) {
|
|
newElements.push_back(decl);
|
|
return false;
|
|
}
|
|
|
|
// Diagnose #warning / #error during application.
|
|
if (auto poundDiag = dyn_cast<PoundDiagnosticDecl>(decl)) {
|
|
TypeChecker::typeCheckDecl(poundDiag);
|
|
newElements.push_back(decl);
|
|
return false;
|
|
}
|
|
|
|
// Skip variable declarations; they're always part of a pattern
|
|
// binding.
|
|
if (isa<VarDecl>(decl)) {
|
|
TypeChecker::typeCheckDecl(decl);
|
|
newElements.push_back(decl);
|
|
return false;
|
|
}
|
|
|
|
// Handle pattern bindings.
|
|
if (auto patternBinding = dyn_cast<PatternBindingDecl>(decl)) {
|
|
auto resultTarget = rewriteTarget(SyntacticElementTarget{patternBinding});
|
|
assert(resultTarget.has_value() &&
|
|
"Could not rewrite pattern binding entries!");
|
|
TypeChecker::typeCheckDecl(resultTarget->getAsPatternBinding());
|
|
newElements.push_back(resultTarget->getAsPatternBinding());
|
|
return false;
|
|
}
|
|
|
|
llvm_unreachable("Cannot yet handle declarations");
|
|
}
|
|
|
|
NullablePtr<Stmt>
|
|
visitBraceStmt(BraceStmt *braceStmt, ResultBuilderTarget target,
|
|
Optional<ResultBuilderTarget> innerTarget = None) {
|
|
std::vector<ASTNode> newElements;
|
|
|
|
// If there is an "inner" target corresponding to this brace, declare
|
|
// it's temporary variable if needed.
|
|
if (innerTarget)
|
|
declareTemporaryVariable(innerTarget->captured.first, newElements);
|
|
|
|
for (auto node : braceStmt->getElements()) {
|
|
if (visitBraceElement(node, newElements))
|
|
return nullptr;
|
|
}
|
|
|
|
// If there is an "inner" target corresponding to this brace, initialize
|
|
// it.
|
|
if (innerTarget) {
|
|
newElements.push_back(initializeTarget(*innerTarget));
|
|
}
|
|
|
|
// Capture the result of the buildBlock() call in the manner requested
|
|
// by the caller.
|
|
newElements.push_back(initializeTarget(target));
|
|
|
|
return BraceStmt::create(ctx, braceStmt->getLBraceLoc(), newElements,
|
|
braceStmt->getRBraceLoc());
|
|
}
|
|
|
|
NullablePtr<Stmt> visitIfStmt(IfStmt *ifStmt, ResultBuilderTarget target) {
|
|
// Rewrite the condition.
|
|
if (auto condition =
|
|
rewriteTarget(SyntacticElementTarget(ifStmt->getCond(), dc)))
|
|
ifStmt->setCond(*condition->getAsStmtCondition());
|
|
|
|
assert(target.kind == ResultBuilderTarget::TemporaryVar);
|
|
auto temporaryVar = target.captured.first;
|
|
|
|
// Translate the "then" branch.
|
|
auto capturedThen = takeCapturedStmt(ifStmt->getThenStmt());
|
|
auto newThen = visitBraceStmt(cast<BraceStmt>(ifStmt->getThenStmt()),
|
|
ResultBuilderTarget::forAssign(
|
|
temporaryVar, {target.captured.second[0]}),
|
|
ResultBuilderTarget::forAssign(
|
|
capturedThen.first, {capturedThen.second.front()}));
|
|
if (!newThen)
|
|
return nullptr;
|
|
|
|
ifStmt->setThenStmt(newThen.get());
|
|
|
|
// Look for a #available condition. If there is one, we need to check
|
|
// that the resulting type of the "then" doesn't refer to any types that
|
|
// are unavailable in the enclosing context.
|
|
//
|
|
// Note that this is for staging in support for buildLimitedAvailability();
|
|
// the diagnostic is currently a warning, so that existing code that
|
|
// compiles today will continue to compile. Once result builder types
|
|
// have had the chance to adopt buildLimitedAvailability(), we'll upgrade
|
|
// this warning to an error.
|
|
if (auto availabilityCond = findAvailabilityCondition(ifStmt->getCond())) {
|
|
SourceLoc loc = availabilityCond->getStartLoc();
|
|
Type bodyType;
|
|
if (availabilityCond->getAvailability()->isUnavailability()) {
|
|
// For #unavailable, we need to check the "else".
|
|
Type elseBodyType = solution.simplifyType(
|
|
solution.getType(target.captured.second[1]));
|
|
bodyType = elseBodyType;
|
|
} else {
|
|
Type thenBodyType = solution.simplifyType(
|
|
solution.getType(target.captured.second[0]));
|
|
bodyType = thenBodyType;
|
|
}
|
|
bodyType.findIf([&](Type type) {
|
|
auto nominal = type->getAnyNominal();
|
|
if (!nominal)
|
|
return false;
|
|
|
|
ExportContext where = ExportContext::forFunctionBody(dc, loc);
|
|
if (auto reason = TypeChecker::checkDeclarationAvailability(
|
|
nominal, where)) {
|
|
ctx.Diags.diagnose(
|
|
loc, diag::result_builder_missing_limited_availability,
|
|
builderTransform.builderType);
|
|
|
|
// Add a note to the result builder with a stub for
|
|
// buildLimitedAvailability().
|
|
if (auto builder = builderTransform.builderType->getAnyNominal()) {
|
|
SourceLoc buildInsertionLoc;
|
|
std::string stubIndent;
|
|
Type componentType;
|
|
std::tie(buildInsertionLoc, stubIndent, componentType) =
|
|
determineResultBuilderBuildFixItInfo(builder);
|
|
if (buildInsertionLoc.isValid()) {
|
|
std::string fixItString;
|
|
{
|
|
llvm::raw_string_ostream out(fixItString);
|
|
printResultBuilderBuildFunction(
|
|
builder, componentType,
|
|
ResultBuilderBuildFunction::BuildLimitedAvailability,
|
|
stubIndent, out);
|
|
|
|
builder->diagnose(
|
|
diag::result_builder_missing_build_limited_availability,
|
|
builderTransform.builderType)
|
|
.fixItInsert(buildInsertionLoc, fixItString);
|
|
}
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
});
|
|
}
|
|
|
|
if (auto elseBraceStmt =
|
|
dyn_cast_or_null<BraceStmt>(ifStmt->getElseStmt())) {
|
|
// Translate the "else" branch when it's a stmt-brace.
|
|
auto capturedElse = takeCapturedStmt(elseBraceStmt);
|
|
auto newElse = visitBraceStmt(
|
|
elseBraceStmt,
|
|
ResultBuilderTarget::forAssign(
|
|
temporaryVar, {target.captured.second[1]}),
|
|
ResultBuilderTarget::forAssign(
|
|
capturedElse.first, {capturedElse.second.front()}));
|
|
if (!newElse)
|
|
return nullptr;
|
|
|
|
ifStmt->setElseStmt(newElse.get());
|
|
} else if (auto elseIfStmt = cast_or_null<IfStmt>(ifStmt->getElseStmt())){
|
|
// Translate the "else" branch when it's an else-if.
|
|
auto capturedElse = takeCapturedStmt(elseIfStmt);
|
|
std::vector<ASTNode> newElseElements;
|
|
declareTemporaryVariable(capturedElse.first, newElseElements);
|
|
auto newElseElt =
|
|
visitIfStmt(elseIfStmt, ResultBuilderTarget::forAssign(
|
|
capturedElse.first, capturedElse.second));
|
|
if (!newElseElt)
|
|
return nullptr;
|
|
|
|
newElseElements.push_back(newElseElt.get());
|
|
newElseElements.push_back(
|
|
initializeTarget(
|
|
ResultBuilderTarget::forAssign(
|
|
temporaryVar, {target.captured.second[1]})));
|
|
|
|
Stmt *newElse = BraceStmt::create(
|
|
ctx, elseIfStmt->getStartLoc(), newElseElements,
|
|
elseIfStmt->getEndLoc());
|
|
ifStmt->setElseStmt(newElse);
|
|
} else {
|
|
// Form an "else" brace containing an assignment to the temporary
|
|
// variable.
|
|
auto init = initializeTarget(
|
|
ResultBuilderTarget::forAssign(
|
|
temporaryVar, {target.captured.second[1]}));
|
|
auto newElse = BraceStmt::create(
|
|
ctx, ifStmt->getEndLoc(), { init }, ifStmt->getEndLoc());
|
|
ifStmt->setElseStmt(newElse);
|
|
}
|
|
|
|
return ifStmt;
|
|
}
|
|
|
|
NullablePtr<Stmt> visitDoStmt(DoStmt *doStmt, ResultBuilderTarget target) {
|
|
// Each statement turns into a (potential) temporary variable
|
|
// binding followed by the statement itself.
|
|
auto body = cast<BraceStmt>(doStmt->getBody());
|
|
auto captured = takeCapturedStmt(body);
|
|
|
|
auto newInnerBody =
|
|
visitBraceStmt(body, target,
|
|
ResultBuilderTarget::forAssign(
|
|
captured.first, {captured.second.front()}));
|
|
if (!newInnerBody)
|
|
return nullptr;
|
|
|
|
doStmt->setBody(cast<BraceStmt>(newInnerBody.get()));
|
|
return doStmt;
|
|
}
|
|
|
|
NullablePtr<Stmt> visitSwitchStmt(SwitchStmt *switchStmt,
|
|
ResultBuilderTarget target) {
|
|
// Translate the subject expression.
|
|
ConstraintSystem &cs = solution.getConstraintSystem();
|
|
auto subjectTarget = rewriteTarget(*cs.getTargetFor(switchStmt));
|
|
if (!subjectTarget)
|
|
return nullptr;
|
|
|
|
switchStmt->setSubjectExpr(subjectTarget->getAsExpr());
|
|
|
|
// Handle any declaration nodes within the case list first; we'll
|
|
// handle the cases in a second pass.
|
|
for (auto child : switchStmt->getRawCases()) {
|
|
if (auto decl = child.dyn_cast<Decl *>()) {
|
|
TypeChecker::typeCheckDecl(decl);
|
|
}
|
|
}
|
|
|
|
// Translate all of the cases.
|
|
bool limitExhaustivityChecks = false;
|
|
assert(target.kind == ResultBuilderTarget::TemporaryVar);
|
|
auto temporaryVar = target.captured.first;
|
|
unsigned caseIndex = 0;
|
|
for (auto caseStmt : switchStmt->getCases()) {
|
|
if (!visitCaseStmt(
|
|
caseStmt,
|
|
ResultBuilderTarget::forAssign(
|
|
temporaryVar, {target.captured.second[caseIndex]})))
|
|
return nullptr;
|
|
|
|
// Check restrictions on '@unknown'.
|
|
if (caseStmt->hasUnknownAttr()) {
|
|
checkUnknownAttrRestrictions(
|
|
cs.getASTContext(), caseStmt, limitExhaustivityChecks);
|
|
}
|
|
|
|
++caseIndex;
|
|
}
|
|
|
|
TypeChecker::checkSwitchExhaustiveness(
|
|
switchStmt, dc, limitExhaustivityChecks);
|
|
|
|
return switchStmt;
|
|
}
|
|
|
|
NullablePtr<Stmt> visitCaseStmt(CaseStmt *caseStmt,
|
|
ResultBuilderTarget target) {
|
|
// Translate the patterns and guard expressions for each case label item.
|
|
for (auto &caseLabelItem : caseStmt->getMutableCaseLabelItems()) {
|
|
SyntacticElementTarget caseLabelTarget(&caseLabelItem, dc);
|
|
if (!rewriteTarget(caseLabelTarget))
|
|
return nullptr;
|
|
}
|
|
|
|
// Setup the types of our case body var decls.
|
|
for (auto *expected : caseStmt->getCaseBodyVariablesOrEmptyArray()) {
|
|
assert(expected->hasName());
|
|
auto prev = expected->getParentVarDecl();
|
|
auto type = solution.resolveInterfaceType(
|
|
solution.getType(prev)->mapTypeOutOfContext());
|
|
expected->setInterfaceType(type);
|
|
}
|
|
|
|
// Transform the body of the case.
|
|
auto body = cast<BraceStmt>(caseStmt->getBody());
|
|
auto captured = takeCapturedStmt(body);
|
|
auto newInnerBody =
|
|
visitBraceStmt(body, target,
|
|
ResultBuilderTarget::forAssign(
|
|
captured.first, {captured.second.front()}));
|
|
if (!newInnerBody)
|
|
return nullptr;
|
|
|
|
caseStmt->setBody(cast<BraceStmt>(newInnerBody.get()));
|
|
return caseStmt;
|
|
}
|
|
|
|
NullablePtr<Stmt> visitForEachStmt(ForEachStmt *forEachStmt,
|
|
ResultBuilderTarget target) {
|
|
// Translate the for-each loop header.
|
|
ConstraintSystem &cs = solution.getConstraintSystem();
|
|
auto forEachTarget = rewriteTarget(*cs.getTargetFor(forEachStmt));
|
|
if (!forEachTarget)
|
|
return nullptr;
|
|
|
|
const auto &captured = target.captured;
|
|
auto finalForEachVar = captured.first;
|
|
auto arrayVarRef = captured.second[0];
|
|
auto arrayVar = cast<VarDecl>(cast<DeclRefExpr>(arrayVarRef)->getDecl());
|
|
auto arrayInitExpr = captured.second[1];
|
|
auto arrayAppendCall = captured.second[2];
|
|
auto buildArrayCall = captured.second[3];
|
|
|
|
// Collect the three steps to initialize the array variable to an
|
|
// empty array, execute the loop to collect the results of each iteration,
|
|
// then form the buildArray() call to the write the result.
|
|
std::vector<ASTNode> outerBodySteps;
|
|
|
|
// Step 1: Declare and initialize the array variable.
|
|
arrayVar->setInterfaceType(solution.simplifyType(cs.getType(arrayVar)));
|
|
arrayInitExpr = rewriteExpr(arrayInitExpr);
|
|
declareTemporaryVariable(arrayVar, outerBodySteps, arrayInitExpr);
|
|
|
|
// Step 2. Transform the body of the for-each statement. Each iteration
|
|
// will append the result of executing the loop body to the array.
|
|
auto body = forEachStmt->getBody();
|
|
auto capturedBody = takeCapturedStmt(body);
|
|
auto newBody = visitBraceStmt(
|
|
body, ResultBuilderTarget::forExpression(arrayAppendCall),
|
|
ResultBuilderTarget::forAssign(capturedBody.first,
|
|
{capturedBody.second.front()}));
|
|
if (!newBody)
|
|
return nullptr;
|
|
|
|
forEachStmt->setBody(cast<BraceStmt>(newBody.get()));
|
|
outerBodySteps.push_back(forEachStmt);
|
|
|
|
// Step 3. Perform the buildArray() call to turn the array of results
|
|
// collected from the iterations into a single value under the control of
|
|
// the result builder.
|
|
outerBodySteps.push_back(
|
|
initializeTarget(
|
|
ResultBuilderTarget::forAssign(finalForEachVar, {buildArrayCall})));
|
|
|
|
// Form a brace statement to put together the three main steps for the
|
|
// for-each loop translation outlined above.
|
|
return BraceStmt::create(ctx, forEachStmt->getStartLoc(), outerBodySteps,
|
|
newBody.get()->getEndLoc());
|
|
}
|
|
|
|
NullablePtr<Stmt> visitThrowStmt(ThrowStmt *throwStmt) {
|
|
// Rewrite the error.
|
|
auto target = *solution.getConstraintSystem().getTargetFor(throwStmt);
|
|
if (auto result = rewriteTarget(target))
|
|
throwStmt->setSubExpr(result->getAsExpr());
|
|
else
|
|
return nullptr;
|
|
|
|
return throwStmt;
|
|
}
|
|
|
|
NullablePtr<Stmt> visitThrowStmt(ThrowStmt *throwStmt,
|
|
ResultBuilderTarget target) {
|
|
llvm_unreachable("Throw statements produce no value");
|
|
}
|
|
|
|
#define UNHANDLED_RESULT_BUILDER_STMT(STMT) \
|
|
NullablePtr<Stmt> \
|
|
visit##STMT##Stmt(STMT##Stmt *stmt, ResultBuilderTarget target) { \
|
|
llvm_unreachable("Function builders do not allow statement of kind " \
|
|
#STMT); \
|
|
}
|
|
|
|
UNHANDLED_RESULT_BUILDER_STMT(Return)
|
|
UNHANDLED_RESULT_BUILDER_STMT(Yield)
|
|
UNHANDLED_RESULT_BUILDER_STMT(Forget)
|
|
UNHANDLED_RESULT_BUILDER_STMT(Guard)
|
|
UNHANDLED_RESULT_BUILDER_STMT(While)
|
|
UNHANDLED_RESULT_BUILDER_STMT(Defer)
|
|
UNHANDLED_RESULT_BUILDER_STMT(DoCatch)
|
|
UNHANDLED_RESULT_BUILDER_STMT(RepeatWhile)
|
|
UNHANDLED_RESULT_BUILDER_STMT(Break)
|
|
UNHANDLED_RESULT_BUILDER_STMT(Continue)
|
|
UNHANDLED_RESULT_BUILDER_STMT(Fallthrough)
|
|
UNHANDLED_RESULT_BUILDER_STMT(Fail)
|
|
UNHANDLED_RESULT_BUILDER_STMT(PoundAssert)
|
|
#undef UNHANDLED_RESULT_BUILDER_STMT
|
|
};
|
|
|
|
} // end anonymous namespace
|
|
|
|
BraceStmt *swift::applyResultBuilderTransform(
|
|
const Solution &solution, AppliedBuilderTransform applied, BraceStmt *body,
|
|
DeclContext *dc,
|
|
std::function<Optional<SyntacticElementTarget>(SyntacticElementTarget)>
|
|
rewriteTarget) {
|
|
BuilderClosureRewriter rewriter(solution, dc, applied, rewriteTarget);
|
|
auto captured = rewriter.takeCapturedStmt(body);
|
|
auto result = rewriter.visitBraceStmt(
|
|
body, ResultBuilderTarget::forReturn(applied.returnExpr),
|
|
ResultBuilderTarget::forAssign(captured.first, captured.second));
|
|
if (!result)
|
|
return nullptr;
|
|
return cast<BraceStmt>(result.get());
|
|
}
|
|
|
|
Optional<BraceStmt *> TypeChecker::applyResultBuilderBodyTransform(
|
|
FuncDecl *func, Type builderType,
|
|
bool ClosuresInResultBuilderDontParticipateInInference) {
|
|
// Pre-check the body: pre-check any expressions in it and look
|
|
// for return statements.
|
|
//
|
|
// If we encountered an error or there was an explicit result type,
|
|
// bail out and report that to the caller.
|
|
auto &ctx = func->getASTContext();
|
|
auto request =
|
|
PreCheckResultBuilderRequest{{AnyFunctionRef(func),
|
|
/*SuppressDiagnostics=*/false}};
|
|
switch (evaluateOrDefault(ctx.evaluator, request,
|
|
ResultBuilderBodyPreCheck::Error)) {
|
|
case ResultBuilderBodyPreCheck::Okay:
|
|
// If the pre-check was okay, apply the result-builder transform.
|
|
break;
|
|
|
|
case ResultBuilderBodyPreCheck::Error:
|
|
return nullptr;
|
|
|
|
case ResultBuilderBodyPreCheck::HasReturnStmt: {
|
|
// One or more explicit 'return' statements were encountered, which
|
|
// disables the result builder transform. Warn when we do this.
|
|
auto returnStmts = findReturnStatements(func);
|
|
assert(!returnStmts.empty());
|
|
|
|
ctx.Diags.diagnose(
|
|
returnStmts.front()->getReturnLoc(),
|
|
diag::result_builder_disabled_by_return_warn, builderType);
|
|
|
|
// Note that one can remove the result builder attribute.
|
|
auto attr = func->getAttachedResultBuilder();
|
|
if (!attr) {
|
|
if (auto accessor = dyn_cast<AccessorDecl>(func)) {
|
|
attr = accessor->getStorage()->getAttachedResultBuilder();
|
|
}
|
|
}
|
|
|
|
if (attr) {
|
|
diagnoseAndRemoveAttr(func, attr, diag::result_builder_remove_attr);
|
|
}
|
|
|
|
// Note that one can remove all of the return statements.
|
|
{
|
|
auto diag = ctx.Diags.diagnose(
|
|
returnStmts.front()->getReturnLoc(),
|
|
diag::result_builder_remove_returns);
|
|
for (auto returnStmt : returnStmts) {
|
|
diag.fixItRemove(returnStmt->getReturnLoc());
|
|
}
|
|
}
|
|
|
|
return None;
|
|
}
|
|
}
|
|
|
|
ConstraintSystemOptions options = ConstraintSystemFlags::AllowFixes;
|
|
if (ClosuresInResultBuilderDontParticipateInInference) {
|
|
options |= ConstraintSystemFlags::
|
|
ClosuresInResultBuildersDontParticipateInInference;
|
|
}
|
|
auto resultInterfaceTy = func->getResultInterfaceType();
|
|
auto resultContextType = func->mapTypeIntoContext(resultInterfaceTy);
|
|
|
|
// Determine whether we're inferring the underlying type for the opaque
|
|
// result type of this function.
|
|
ConstraintKind resultConstraintKind = ConstraintKind::Conversion;
|
|
if (auto opaque = resultContextType->getAs<OpaqueTypeArchetypeType>()) {
|
|
if (opaque->getDecl()->isOpaqueReturnTypeOfFunction(func)) {
|
|
resultConstraintKind = ConstraintKind::Equal;
|
|
}
|
|
}
|
|
|
|
// Build a constraint system in which we can check the body of the function.
|
|
ConstraintSystem cs(func, options);
|
|
|
|
if (cs.isDebugMode()) {
|
|
auto &log = llvm::errs();
|
|
|
|
log << "--- Applying result builder to function ---\n";
|
|
func->dump(log);
|
|
log << '\n';
|
|
}
|
|
|
|
// Map type parameters into context. We don't want type
|
|
// parameters to appear in the result builder type, because
|
|
// the result builder type will only be used inside the body
|
|
// of this decl; it's not part of the interface type.
|
|
builderType = func->mapTypeIntoContext(builderType);
|
|
|
|
if (auto result = cs.matchResultBuilder(
|
|
func, builderType, resultContextType, resultConstraintKind,
|
|
/*contextualType=*/Type(),
|
|
cs.getConstraintLocator(func->getBody()))) {
|
|
if (result->isFailure())
|
|
return nullptr;
|
|
}
|
|
|
|
// Solve the constraint system.
|
|
if (cs.getASTContext().CompletionCallback) {
|
|
SmallVector<Solution, 4> solutions;
|
|
cs.solveForCodeCompletion(solutions);
|
|
|
|
CompletionContextFinder analyzer(func, func->getDeclContext());
|
|
if (analyzer.hasCompletion()) {
|
|
filterSolutionsForCodeCompletion(solutions, analyzer);
|
|
for (const auto &solution : solutions) {
|
|
cs.getASTContext().CompletionCallback->sawSolution(solution);
|
|
}
|
|
}
|
|
return nullptr;
|
|
}
|
|
|
|
SmallVector<Solution, 4> solutions;
|
|
bool solvingFailed = cs.solve(solutions);
|
|
|
|
auto reportSolutionsToSolutionCallback = [&](const SolutionResult &result) {
|
|
if (!cs.getASTContext().SolutionCallback) {
|
|
return;
|
|
}
|
|
switch (result.getKind()) {
|
|
case SolutionResult::Success:
|
|
cs.getASTContext().SolutionCallback->sawSolution(result.getSolution());
|
|
break;
|
|
case SolutionResult::Ambiguous:
|
|
for (auto &solution : result.getAmbiguousSolutions()) {
|
|
cs.getASTContext().SolutionCallback->sawSolution(solution);
|
|
}
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
};
|
|
|
|
if (solvingFailed || solutions.size() != 1) {
|
|
// Try to fix the system or provide a decent diagnostic.
|
|
auto salvagedResult = cs.salvage();
|
|
switch (salvagedResult.getKind()) {
|
|
case SolutionResult::Kind::Success:
|
|
solutions.clear();
|
|
solutions.push_back(std::move(salvagedResult).takeSolution());
|
|
break;
|
|
|
|
case SolutionResult::Kind::Error:
|
|
case SolutionResult::Kind::Ambiguous:
|
|
reportSolutionsToSolutionCallback(salvagedResult);
|
|
return nullptr;
|
|
|
|
case SolutionResult::Kind::UndiagnosedError:
|
|
reportSolutionsToSolutionCallback(salvagedResult);
|
|
cs.diagnoseFailureFor(SyntacticElementTarget(func));
|
|
salvagedResult.markAsDiagnosed();
|
|
return nullptr;
|
|
|
|
case SolutionResult::Kind::TooComplex:
|
|
reportSolutionsToSolutionCallback(salvagedResult);
|
|
func->diagnose(diag::expression_too_complex)
|
|
.highlight(func->getBodySourceRange());
|
|
salvagedResult.markAsDiagnosed();
|
|
return nullptr;
|
|
}
|
|
|
|
// The system was salvaged; continue on as if nothing happened.
|
|
}
|
|
|
|
if (cs.isDebugMode()) {
|
|
auto indent = cs.solverState ? cs.solverState->getCurrentIndent() : 0;
|
|
auto &log = llvm::errs().indent(indent);
|
|
log << "--- Applying Solution ---\n";
|
|
solutions.front().dump(log, indent);
|
|
log << '\n';
|
|
}
|
|
|
|
if (cs.getASTContext().SolutionCallback) {
|
|
for (auto &solution : solutions) {
|
|
cs.getASTContext().SolutionCallback->sawSolution(solution);
|
|
}
|
|
return nullptr;
|
|
}
|
|
|
|
// FIXME: Shouldn't need to do this.
|
|
cs.applySolution(solutions.front());
|
|
|
|
// Apply the solution to the function body.
|
|
if (auto result =
|
|
cs.applySolution(solutions.front(), SyntacticElementTarget(func))) {
|
|
performSyntacticDiagnosticsForTarget(*result, /*isExprStmt*/ false);
|
|
auto *body = result->getFunctionBody();
|
|
|
|
if (cs.isDebugMode()) {
|
|
auto indent = cs.solverState ? cs.solverState->getCurrentIndent() : 0;
|
|
auto &log = llvm::errs().indent(indent);
|
|
log << "--- Type-checked function body ---\n";
|
|
body->dump(log);
|
|
log << '\n';
|
|
}
|
|
|
|
return body;
|
|
}
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
Optional<ConstraintSystem::TypeMatchResult>
|
|
ConstraintSystem::matchResultBuilder(AnyFunctionRef fn, Type builderType,
|
|
Type bodyResultType,
|
|
ConstraintKind bodyResultConstraintKind,
|
|
Type contextualType,
|
|
ConstraintLocatorBuilder locator) {
|
|
builderType = simplifyType(builderType);
|
|
auto builder = builderType->getAnyNominal();
|
|
assert(builder && "Bad result builder type");
|
|
assert(builder->getAttrs().hasAttribute<ResultBuilderAttr>());
|
|
assert(!builderType->hasTypeParameter());
|
|
|
|
if (InvalidResultBuilderBodies.count(fn)) {
|
|
(void)recordFix(IgnoreInvalidResultBuilderBody::create(
|
|
*this, getConstraintLocator(fn.getAbstractClosureExpr())));
|
|
return getTypeMatchSuccess();
|
|
}
|
|
|
|
// We have already pre-checked the result builder body. Technically, we
|
|
// shouldn't need to do anything here, but there was a bug here that we did
|
|
// not apply the result builder transform if it contained an explicit return.
|
|
// To maintain source compatibility, we still need to check for HasReturnStmt.
|
|
// https://github.com/apple/swift/issues/64332.
|
|
auto request =
|
|
PreCheckResultBuilderRequest{{fn, /*SuppressDiagnostics=*/false}};
|
|
switch (evaluateOrDefault(getASTContext().evaluator, request,
|
|
ResultBuilderBodyPreCheck::Error)) {
|
|
case ResultBuilderBodyPreCheck::Okay:
|
|
// If the pre-check was okay, apply the result-builder transform.
|
|
break;
|
|
|
|
case ResultBuilderBodyPreCheck::Error: {
|
|
llvm_unreachable(
|
|
"Running PreCheckResultBuilderRequest on a function shouldn't run "
|
|
"preCheckExpression and thus we should never enter this case.");
|
|
break;
|
|
}
|
|
|
|
case ResultBuilderBodyPreCheck::HasReturnStmt:
|
|
// Diagnostic mode means that solver couldn't reach any viable
|
|
// solution, so let's diagnose presence of a `return` statement
|
|
// in the closure body.
|
|
if (shouldAttemptFixes()) {
|
|
if (recordFix(IgnoreResultBuilderWithReturnStmts::create(
|
|
*this, builderType,
|
|
getConstraintLocator(fn.getAbstractClosureExpr()))))
|
|
return getTypeMatchFailure(locator);
|
|
|
|
return getTypeMatchSuccess();
|
|
}
|
|
|
|
// If the body has a return statement, suppress the transform but
|
|
// continue solving the constraint system.
|
|
return None;
|
|
}
|
|
|
|
auto disableASTTransform = [&](NominalTypeDecl *builder) { return false; };
|
|
|
|
if (!disableASTTransform(builder)) {
|
|
auto transformedBody = getBuilderTransformedBody(fn, builder);
|
|
// If this builder transform has not yet been applied to this function,
|
|
// let's do it and cache the result.
|
|
if (!transformedBody) {
|
|
ResultBuilderTransform transform(*this, fn.getAsDeclContext(),
|
|
builderType, bodyResultType);
|
|
auto *body = transform.apply(fn.getBody());
|
|
|
|
if (auto unsupported = transform.getUnsupportedElement()) {
|
|
assert(!body);
|
|
|
|
// If we aren't supposed to attempt fixes, fail.
|
|
if (!shouldAttemptFixes()) {
|
|
return getTypeMatchFailure(locator);
|
|
}
|
|
|
|
// If we're solving for code completion and the body contains the code
|
|
// completion location, skipping it won't get us to a useful solution so
|
|
// just bail.
|
|
if (isForCodeCompletion() &&
|
|
containsIDEInspectionTarget(fn.getBody())) {
|
|
return getTypeMatchFailure(locator);
|
|
}
|
|
|
|
// Record the first unhandled construct as a fix.
|
|
if (recordFix(
|
|
SkipUnhandledConstructInResultBuilder::create(
|
|
*this, unsupported, builder, getConstraintLocator(locator)),
|
|
/*impact=*/100)) {
|
|
return getTypeMatchFailure(locator);
|
|
}
|
|
|
|
if (auto *closure =
|
|
getAsExpr<ClosureExpr>(fn.getAbstractClosureExpr())) {
|
|
auto closureTy = getClosureType(closure);
|
|
simplifyType(closureTy).visit([&](Type componentTy) {
|
|
if (auto *typeVar = componentTy->getAs<TypeVariableType>()) {
|
|
assignFixedType(typeVar,
|
|
PlaceholderType::get(getASTContext(), typeVar));
|
|
}
|
|
});
|
|
}
|
|
|
|
return getTypeMatchSuccess();
|
|
}
|
|
|
|
transformedBody = std::make_pair(transform.getBuilderSelf(), body);
|
|
// Record the transformation so it could be re-used if needed.
|
|
setBuilderTransformedBody(fn, builder, transformedBody->first,
|
|
transformedBody->second);
|
|
}
|
|
|
|
// Set the type of `$__builderSelf` variable before constraint generation.
|
|
setType(transformedBody->first, MetatypeType::get(builderType));
|
|
|
|
if (isDebugMode()) {
|
|
auto &log = llvm::errs();
|
|
auto indent = solverState ? solverState->getCurrentIndent() : 0;
|
|
log.indent(indent) << "------- Transformed Body -------\n";
|
|
transformedBody->second->dump(log, &getASTContext(), indent);
|
|
log << '\n';
|
|
}
|
|
|
|
AppliedBuilderTransform transformInfo;
|
|
|
|
transformInfo.builderType = builderType;
|
|
transformInfo.bodyResultType = bodyResultType;
|
|
transformInfo.contextualType = contextualType;
|
|
transformInfo.transformedBody = transformedBody->second;
|
|
|
|
// Record the transformation.
|
|
assert(
|
|
std::find_if(
|
|
resultBuilderTransformed.begin(), resultBuilderTransformed.end(),
|
|
[&](const std::pair<AnyFunctionRef, AppliedBuilderTransform> &elt) {
|
|
return elt.first == fn;
|
|
}) == resultBuilderTransformed.end() &&
|
|
"already transformed this body along this path!?!");
|
|
resultBuilderTransformed.insert(
|
|
std::make_pair(fn, std::move(transformInfo)));
|
|
|
|
if (generateConstraints(fn, transformInfo.transformedBody.get()))
|
|
return getTypeMatchFailure(locator);
|
|
|
|
return getTypeMatchSuccess();
|
|
}
|
|
|
|
// Check the form of this body to see if we can apply the
|
|
// result-builder translation at all.
|
|
auto dc = fn.getAsDeclContext();
|
|
{
|
|
// Check whether we can apply this specific result builder.
|
|
BuilderClosureVisitor visitor(getASTContext(), nullptr, dc, builderType,
|
|
bodyResultType);
|
|
|
|
// If we saw a control-flow statement or declaration that the builder
|
|
// cannot handle, we don't have a well-formed result builder application.
|
|
if (auto unhandledNode = visitor.check(fn.getBody())) {
|
|
// If we aren't supposed to attempt fixes, fail.
|
|
if (!shouldAttemptFixes()) {
|
|
return getTypeMatchFailure(locator);
|
|
}
|
|
|
|
// If we're solving for code completion and the body contains the code
|
|
// completion location, skipping it won't get us to a useful solution so
|
|
// just bail.
|
|
if (isForCodeCompletion() && containsIDEInspectionTarget(fn.getBody())) {
|
|
return getTypeMatchFailure(locator);
|
|
}
|
|
|
|
// Record the first unhandled construct as a fix.
|
|
if (recordFix(
|
|
SkipUnhandledConstructInResultBuilder::create(
|
|
*this, unhandledNode, builder,
|
|
getConstraintLocator(locator)))) {
|
|
return getTypeMatchFailure(locator);
|
|
}
|
|
}
|
|
}
|
|
|
|
BuilderClosureVisitor visitor(getASTContext(), this, dc, builderType,
|
|
bodyResultType);
|
|
|
|
Optional<AppliedBuilderTransform> applied = None;
|
|
{
|
|
DiagnosticTransaction transaction(dc->getASTContext().Diags);
|
|
|
|
applied = visitor.apply(fn.getBody());
|
|
if (!applied)
|
|
return getTypeMatchFailure(locator);
|
|
|
|
if (transaction.hasErrors()) {
|
|
InvalidResultBuilderBodies.insert(fn);
|
|
|
|
if (recordFix(IgnoreInvalidResultBuilderBody::create(
|
|
*this, getConstraintLocator(fn.getAbstractClosureExpr()))))
|
|
return getTypeMatchFailure(locator);
|
|
|
|
return getTypeMatchSuccess();
|
|
}
|
|
}
|
|
|
|
Type transformedType = getType(applied->returnExpr);
|
|
assert(transformedType && "Missing type");
|
|
|
|
// Record the transformation.
|
|
assert(std::find_if(
|
|
resultBuilderTransformed.begin(),
|
|
resultBuilderTransformed.end(),
|
|
[&](const std::pair<AnyFunctionRef, AppliedBuilderTransform> &elt) {
|
|
return elt.first == fn;
|
|
}) == resultBuilderTransformed.end() &&
|
|
"already transformed this body along this path!?!");
|
|
resultBuilderTransformed.insert(std::make_pair(fn, std::move(*applied)));
|
|
|
|
// If builder is applied to the closure expression then
|
|
// `closure body` to `closure result` matching should
|
|
// use special locator.
|
|
if (auto *closure = fn.getAbstractClosureExpr()) {
|
|
locator = getConstraintLocator(closure, ConstraintLocator::ClosureResult);
|
|
} else {
|
|
locator = getConstraintLocator(fn.getAbstractFunctionDecl(),
|
|
ConstraintLocator::ResultBuilderBodyResult);
|
|
}
|
|
|
|
// Bind the body result type to the type of the transformed expression.
|
|
addConstraint(bodyResultConstraintKind, transformedType,
|
|
openOpaqueType(bodyResultType, CTP_ReturnStmt, locator),
|
|
locator);
|
|
return getTypeMatchSuccess();
|
|
}
|
|
|
|
namespace {
|
|
|
|
/// Pre-check all the expressions in the body.
|
|
class PreCheckResultBuilderApplication : public ASTWalker {
|
|
AnyFunctionRef Fn;
|
|
bool SkipPrecheck = false;
|
|
bool SuppressDiagnostics = false;
|
|
std::vector<ReturnStmt *> ReturnStmts;
|
|
bool HasError = false;
|
|
|
|
bool hasReturnStmt() const { return !ReturnStmts.empty(); }
|
|
|
|
public:
|
|
PreCheckResultBuilderApplication(AnyFunctionRef fn, bool skipPrecheck,
|
|
bool suppressDiagnostics)
|
|
: Fn(fn), SkipPrecheck(skipPrecheck),
|
|
SuppressDiagnostics(suppressDiagnostics) {}
|
|
|
|
const std::vector<ReturnStmt *> getReturnStmts() const { return ReturnStmts; }
|
|
|
|
ResultBuilderBodyPreCheck run() {
|
|
Stmt *oldBody = Fn.getBody();
|
|
|
|
Stmt *newBody = oldBody->walk(*this);
|
|
|
|
// If the walk was aborted, it was because we had a problem of some kind.
|
|
assert((newBody == nullptr) == HasError &&
|
|
"unexpected short-circuit while walking body");
|
|
if (HasError)
|
|
return ResultBuilderBodyPreCheck::Error;
|
|
|
|
assert(oldBody == newBody && "pre-check walk wasn't in-place?");
|
|
|
|
if (hasReturnStmt())
|
|
return ResultBuilderBodyPreCheck::HasReturnStmt;
|
|
|
|
return ResultBuilderBodyPreCheck::Okay;
|
|
}
|
|
|
|
MacroWalking getMacroWalkingBehavior() const override {
|
|
return MacroWalking::Arguments;
|
|
}
|
|
|
|
PreWalkResult<Expr *> walkToExprPre(Expr *E) override {
|
|
if (SkipPrecheck)
|
|
return Action::SkipChildren(E);
|
|
|
|
// Pre-check the expression. If this fails, abort the walk immediately.
|
|
// Otherwise, replace the expression with the result of pre-checking.
|
|
// In either case, don't recurse into the expression.
|
|
{
|
|
auto *DC = Fn.getAsDeclContext();
|
|
auto &diagEngine = DC->getASTContext().Diags;
|
|
|
|
// Suppress any diagnostics which could be produced by this expression.
|
|
DiagnosticTransaction transaction(diagEngine);
|
|
|
|
HasError |= ConstraintSystem::preCheckExpression(
|
|
E, DC, /*replaceInvalidRefsWithErrors=*/true,
|
|
/*leaveClosureBodiesUnchecked=*/false);
|
|
|
|
HasError |= transaction.hasErrors();
|
|
|
|
if (!HasError)
|
|
HasError |= containsErrorExpr(E);
|
|
|
|
if (SuppressDiagnostics)
|
|
transaction.abort();
|
|
|
|
if (HasError)
|
|
return Action::Stop();
|
|
|
|
return Action::SkipChildren(E);
|
|
}
|
|
}
|
|
|
|
PreWalkResult<Stmt *> walkToStmtPre(Stmt *S) override {
|
|
// If we see a return statement, note it..
|
|
if (auto returnStmt = dyn_cast<ReturnStmt>(S)) {
|
|
if (!returnStmt->isImplicit()) {
|
|
ReturnStmts.push_back(returnStmt);
|
|
return Action::SkipChildren(S);
|
|
}
|
|
}
|
|
|
|
// Otherwise, recurse into the statement normally.
|
|
return Action::Continue(S);
|
|
}
|
|
|
|
/// Check whether given expression (including single-statement
|
|
/// closures) contains `ErrorExpr` as one of its sub-expressions.
|
|
bool containsErrorExpr(Expr *expr) {
|
|
bool hasError = false;
|
|
|
|
expr->forEachChildExpr([&](Expr *expr) -> Expr * {
|
|
hasError |= isa<ErrorExpr>(expr);
|
|
if (hasError)
|
|
return nullptr;
|
|
|
|
if (auto *closure = dyn_cast<ClosureExpr>(expr)) {
|
|
if (closure->hasSingleExpressionBody()) {
|
|
hasError |= containsErrorExpr(closure->getSingleExpressionBody());
|
|
return hasError ? nullptr : expr;
|
|
}
|
|
}
|
|
|
|
return expr;
|
|
});
|
|
|
|
return hasError;
|
|
}
|
|
|
|
/// Ignore patterns.
|
|
PreWalkResult<Pattern *> walkToPatternPre(Pattern *pat) override {
|
|
return Action::SkipChildren(pat);
|
|
}
|
|
};
|
|
|
|
}
|
|
|
|
ResultBuilderBodyPreCheck PreCheckResultBuilderRequest::evaluate(
|
|
Evaluator &evaluator, PreCheckResultBuilderDescriptor owner) const {
|
|
// Closures should already be pre-checked when we run this, so there's no need
|
|
// to pre-check them again.
|
|
bool skipPrecheck = owner.Fn.getAbstractClosureExpr();
|
|
return PreCheckResultBuilderApplication(
|
|
owner.Fn, skipPrecheck,
|
|
/*suppressDiagnostics=*/owner.SuppressDiagnostics)
|
|
.run();
|
|
}
|
|
|
|
std::vector<ReturnStmt *> TypeChecker::findReturnStatements(AnyFunctionRef fn) {
|
|
PreCheckResultBuilderApplication precheck(fn, /*skipPreCheck=*/true,
|
|
/*SuppressDiagnostics=*/true);
|
|
(void)precheck.run();
|
|
return precheck.getReturnStmts();
|
|
}
|
|
|
|
ResultBuilderOpSupport TypeChecker::checkBuilderOpSupport(
|
|
Type builderType, DeclContext *dc, Identifier fnName,
|
|
ArrayRef<Identifier> argLabels, SmallVectorImpl<ValueDecl *> *allResults) {
|
|
|
|
auto isUnavailable = [&](Decl *D) -> bool {
|
|
if (AvailableAttr::isUnavailable(D))
|
|
return true;
|
|
|
|
auto loc = extractNearestSourceLoc(dc);
|
|
auto context = ExportContext::forFunctionBody(dc, loc);
|
|
return TypeChecker::checkDeclarationAvailability(D, context).has_value();
|
|
};
|
|
|
|
bool foundMatch = false;
|
|
bool foundUnavailable = false;
|
|
|
|
SmallVector<ValueDecl *, 4> foundDecls;
|
|
dc->lookupQualified(
|
|
builderType, DeclNameRef(fnName),
|
|
NL_QualifiedDefault | NL_ProtocolMembers, foundDecls);
|
|
for (auto decl : foundDecls) {
|
|
if (auto func = dyn_cast<FuncDecl>(decl)) {
|
|
// Function must be static.
|
|
if (!func->isStatic())
|
|
continue;
|
|
|
|
// Function must have the right argument labels, if provided.
|
|
if (!argLabels.empty()) {
|
|
auto funcLabels = func->getName().getArgumentNames();
|
|
if (argLabels.size() > funcLabels.size() ||
|
|
funcLabels.slice(0, argLabels.size()) != argLabels)
|
|
continue;
|
|
}
|
|
|
|
// Check if the the candidate has a suitable availability for the
|
|
// calling context.
|
|
if (isUnavailable(func)) {
|
|
foundUnavailable = true;
|
|
continue;
|
|
}
|
|
foundMatch = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (allResults)
|
|
allResults->append(foundDecls.begin(), foundDecls.end());
|
|
|
|
if (!foundMatch) {
|
|
return foundUnavailable ? ResultBuilderOpSupport::Unavailable
|
|
: ResultBuilderOpSupport::Unsupported;
|
|
}
|
|
// If the builder type itself isn't available, don't consider any builder
|
|
// method available.
|
|
if (auto *D = builderType->getAnyNominal()) {
|
|
if (isUnavailable(D))
|
|
return ResultBuilderOpSupport::Unavailable;
|
|
}
|
|
return ResultBuilderOpSupport::Supported;
|
|
}
|
|
|
|
bool TypeChecker::typeSupportsBuilderOp(
|
|
Type builderType, DeclContext *dc, Identifier fnName,
|
|
ArrayRef<Identifier> argLabels, SmallVectorImpl<ValueDecl *> *allResults) {
|
|
return checkBuilderOpSupport(builderType, dc, fnName, argLabels, allResults)
|
|
.isSupported(/*requireAvailable*/ false);
|
|
}
|
|
|
|
Type swift::inferResultBuilderComponentType(NominalTypeDecl *builder) {
|
|
Type componentType;
|
|
|
|
SmallVector<ValueDecl *, 4> potentialMatches;
|
|
ASTContext &ctx = builder->getASTContext();
|
|
bool supportsBuildBlock = TypeChecker::typeSupportsBuilderOp(
|
|
builder->getDeclaredInterfaceType(), builder, ctx.Id_buildBlock,
|
|
/*argLabels=*/{}, &potentialMatches);
|
|
if (supportsBuildBlock) {
|
|
for (auto decl : potentialMatches) {
|
|
auto func = dyn_cast<FuncDecl>(decl);
|
|
if (!func || !func->isStatic())
|
|
continue;
|
|
|
|
// If we haven't seen a component type before, gather it.
|
|
if (!componentType) {
|
|
componentType = func->getResultInterfaceType();
|
|
continue;
|
|
}
|
|
|
|
// If there are inconsistent component types, bail out.
|
|
if (!componentType->isEqual(func->getResultInterfaceType())) {
|
|
componentType = Type();
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
return componentType;
|
|
}
|
|
|
|
std::tuple<SourceLoc, std::string, Type>
|
|
swift::determineResultBuilderBuildFixItInfo(NominalTypeDecl *builder) {
|
|
SourceLoc buildInsertionLoc = builder->getBraces().Start;
|
|
std::string stubIndent;
|
|
Type componentType;
|
|
|
|
if (buildInsertionLoc.isInvalid())
|
|
return std::make_tuple(buildInsertionLoc, stubIndent, componentType);
|
|
|
|
ASTContext &ctx = builder->getASTContext();
|
|
buildInsertionLoc = Lexer::getLocForEndOfToken(
|
|
ctx.SourceMgr, buildInsertionLoc);
|
|
|
|
StringRef extraIndent;
|
|
StringRef currentIndent = Lexer::getIndentationForLine(
|
|
ctx.SourceMgr, buildInsertionLoc, &extraIndent);
|
|
stubIndent = (currentIndent + extraIndent).str();
|
|
|
|
componentType = inferResultBuilderComponentType(builder);
|
|
return std::make_tuple(buildInsertionLoc, stubIndent, componentType);
|
|
}
|
|
|
|
void swift::printResultBuilderBuildFunction(
|
|
NominalTypeDecl *builder, Type componentType,
|
|
ResultBuilderBuildFunction function,
|
|
Optional<std::string> stubIndent, llvm::raw_ostream &out) {
|
|
// Render the component type into a string.
|
|
std::string componentTypeString;
|
|
if (componentType)
|
|
componentTypeString = componentType.getString();
|
|
else
|
|
componentTypeString = "<#Component#>";
|
|
|
|
// Render the code.
|
|
std::string stubIndentStr = stubIndent.value_or(std::string());
|
|
ExtraIndentStreamPrinter printer(out, stubIndentStr);
|
|
|
|
// If we're supposed to provide a full stub, add a newline and the introducer
|
|
// keywords.
|
|
if (stubIndent) {
|
|
printer.printNewline();
|
|
|
|
if (builder->getFormalAccess() >= AccessLevel::Public)
|
|
printer << "public ";
|
|
|
|
printer << "static func ";
|
|
}
|
|
|
|
bool printedResult = false;
|
|
switch (function) {
|
|
case ResultBuilderBuildFunction::BuildBlock:
|
|
printer << "buildBlock(_ components: " << componentTypeString << "...)";
|
|
break;
|
|
|
|
case ResultBuilderBuildFunction::BuildExpression:
|
|
printer << "buildExpression(_ expression: <#Expression#>)";
|
|
break;
|
|
|
|
case ResultBuilderBuildFunction::BuildOptional:
|
|
printer << "buildOptional(_ component: " << componentTypeString << "?)";
|
|
break;
|
|
|
|
case ResultBuilderBuildFunction::BuildEitherFirst:
|
|
printer << "buildEither(first component: " << componentTypeString << ")";
|
|
break;
|
|
|
|
case ResultBuilderBuildFunction::BuildEitherSecond:
|
|
printer << "buildEither(second component: " << componentTypeString << ")";
|
|
break;
|
|
|
|
case ResultBuilderBuildFunction::BuildArray:
|
|
printer << "buildArray(_ components: [" << componentTypeString << "])";
|
|
break;
|
|
|
|
case ResultBuilderBuildFunction::BuildLimitedAvailability:
|
|
printer << "buildLimitedAvailability(_ component: " << componentTypeString
|
|
<< ")";
|
|
break;
|
|
|
|
case ResultBuilderBuildFunction::BuildFinalResult:
|
|
printer << "buildFinalResult(_ component: " << componentTypeString
|
|
<< ") -> <#Result#>";
|
|
printedResult = true;
|
|
break;
|
|
case ResultBuilderBuildFunction::BuildPartialBlockFirst:
|
|
printer << "buildPartialBlock(first: " << componentTypeString << ")";
|
|
break;
|
|
case ResultBuilderBuildFunction::BuildPartialBlockAccumulated:
|
|
printer << "buildPartialBlock(accumulated: " << componentTypeString
|
|
<< ", next: " << componentTypeString << ")";
|
|
break;
|
|
}
|
|
|
|
if (!printedResult)
|
|
printer << " -> " << componentTypeString;
|
|
|
|
if (stubIndent) {
|
|
printer << " {";
|
|
printer.printNewline();
|
|
printer << " <#code#>";
|
|
printer.printNewline();
|
|
printer << "}";
|
|
}
|
|
}
|
|
|
|
ResultBuilder::ResultBuilder(ConstraintSystem *CS, DeclContext *DC,
|
|
Type builderType)
|
|
: DC(DC), BuilderType(CS ? CS->simplifyType(builderType) : builderType) {
|
|
auto &ctx = DC->getASTContext();
|
|
// Use buildOptional(_:) if available, otherwise fall back to buildIf
|
|
// when available.
|
|
BuildOptionalId =
|
|
(supports(ctx.Id_buildOptional) || !supports(ctx.Id_buildIf))
|
|
? ctx.Id_buildOptional
|
|
: ctx.Id_buildIf;
|
|
|
|
if (CS) {
|
|
BuilderSelf = new (ctx) VarDecl(
|
|
/*isStatic=*/false, VarDecl::Introducer::Let,
|
|
/*nameLoc=*/SourceLoc(), ctx.Id_builderSelf, DC);
|
|
BuilderSelf->setImplicit();
|
|
CS->setType(BuilderSelf, MetatypeType::get(BuilderType));
|
|
}
|
|
}
|
|
|
|
bool ResultBuilder::supportsBuildPartialBlock(bool checkAvailability) {
|
|
auto &ctx = DC->getASTContext();
|
|
return supports(ctx.Id_buildPartialBlock, {ctx.Id_first},
|
|
checkAvailability) &&
|
|
supports(ctx.Id_buildPartialBlock, {ctx.Id_accumulated, ctx.Id_next},
|
|
checkAvailability);
|
|
}
|
|
|
|
bool ResultBuilder::canUseBuildPartialBlock() {
|
|
// If buildPartialBlock doesn't exist at all, we can't use it.
|
|
if (!supportsBuildPartialBlock(/*checkAvailability*/ false))
|
|
return false;
|
|
|
|
// If buildPartialBlock exists and is available, use it.
|
|
if (supportsBuildPartialBlock(/*checkAvailability*/ true))
|
|
return true;
|
|
|
|
// We have buildPartialBlock, but it is unavailable. We can however still
|
|
// use it if buildBlock is also unavailable.
|
|
auto &ctx = DC->getASTContext();
|
|
return supports(ctx.Id_buildBlock) &&
|
|
!supports(ctx.Id_buildBlock, /*labels*/ {},
|
|
/*checkAvailability*/ true);
|
|
}
|
|
|
|
bool ResultBuilder::supports(Identifier fnBaseName,
|
|
ArrayRef<Identifier> argLabels,
|
|
bool checkAvailability) {
|
|
DeclName name(DC->getASTContext(), fnBaseName, argLabels);
|
|
auto known = SupportedOps.find(name);
|
|
if (known != SupportedOps.end())
|
|
return known->second.isSupported(checkAvailability);
|
|
|
|
auto support = TypeChecker::checkBuilderOpSupport(
|
|
BuilderType, DC, fnBaseName, argLabels, /*allResults*/ {});
|
|
SupportedOps.insert({name, support});
|
|
return support.isSupported(checkAvailability);
|
|
}
|
|
|
|
Expr *ResultBuilder::buildCall(SourceLoc loc, Identifier fnName,
|
|
ArrayRef<Expr *> argExprs,
|
|
ArrayRef<Identifier> argLabels) const {
|
|
assert(BuilderSelf);
|
|
|
|
auto &ctx = DC->getASTContext();
|
|
|
|
SmallVector<Argument, 4> args;
|
|
for (auto i : indices(argExprs)) {
|
|
auto *expr = argExprs[i];
|
|
auto label = argLabels.empty() ? Identifier() : argLabels[i];
|
|
auto labelLoc = argLabels.empty() ? SourceLoc() : expr->getStartLoc();
|
|
args.emplace_back(labelLoc, label, expr);
|
|
}
|
|
|
|
auto *baseExpr = new (ctx) DeclRefExpr({BuilderSelf}, DeclNameLoc(loc),
|
|
/*isImplicit=*/true);
|
|
|
|
auto memberRef = new (ctx)
|
|
UnresolvedDotExpr(baseExpr, loc, DeclNameRef(fnName), DeclNameLoc(loc),
|
|
/*implicit=*/true);
|
|
memberRef->setFunctionRefKind(FunctionRefKind::SingleApply);
|
|
|
|
auto openLoc = args.empty() ? loc : argExprs.front()->getStartLoc();
|
|
auto closeLoc = args.empty() ? loc : argExprs.back()->getEndLoc();
|
|
|
|
auto *argList = ArgumentList::createImplicit(ctx, openLoc, args, closeLoc);
|
|
return CallExpr::createImplicit(ctx, memberRef, argList);
|
|
}
|
|
|
|
VarDecl *ResultBuilder::buildVar(SourceLoc loc) {
|
|
auto &ctx = DC->getASTContext();
|
|
// Create the implicit variable.
|
|
Identifier name =
|
|
ctx.getIdentifier(("$__builder" + Twine(VarCounter++)).str());
|
|
auto var = new (ctx)
|
|
VarDecl(/*isStatic=*/false, VarDecl::Introducer::Var, loc, name, DC);
|
|
var->setImplicit();
|
|
return var;
|
|
}
|
|
|
|
DeclRefExpr *ResultBuilder::buildVarRef(VarDecl *var, SourceLoc loc) {
|
|
return new (DC->getASTContext())
|
|
DeclRefExpr(var, DeclNameLoc(loc), /*Implicit=*/true);
|
|
}
|