mirror of
https://github.com/apple/swift.git
synced 2025-12-14 20:36:38 +01:00
edca7c85ad
Convert a bunch of places where we're dumping to stderr and calling `abort` over to using `ABORT` such that the message gets printed to the pretty stack trace. This ensures it gets picked up by CrashReporter.
557 lines
18 KiB
C++
557 lines
18 KiB
C++
//===--- ParameterPack.cpp - Utilities for variadic generics --------------===//
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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) 2022 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 utilities for substituting type parameter packs
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// appearing in pack expansion types.
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//
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//===----------------------------------------------------------------------===//
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#include "swift/AST/ASTContext.h"
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#include "swift/AST/Decl.h"
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#include "swift/AST/GenericEnvironment.h"
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#include "swift/AST/GenericParamList.h"
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#include "swift/AST/ParameterList.h"
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#include "swift/AST/Type.h"
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#include "swift/AST/Types.h"
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#include "swift/Basic/Assertions.h"
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#include "llvm/ADT/SmallVector.h"
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using namespace swift;
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/// FV(PackExpansionType(Pattern, Count), N) = FV(Pattern, N+1)
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/// FV(PackElementType(Param, M), N) = FV(Param, 0) if M >= N, {} otherwise
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/// FV(Param, N) = {Param}
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static Type transformTypeParameterPacksRec(
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Type t, llvm::function_ref<std::optional<Type>(SubstitutableType *)> fn,
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unsigned expansionLevel) {
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return t.transformWithPosition(
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TypePosition::Invariant,
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[&](TypeBase *t, TypePosition p) -> std::optional<Type> {
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// If we're already inside N levels of PackExpansionType, and we're
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// walking into another PackExpansionType, a type parameter pack
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// reference now needs level (N+1) to be free.
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if (auto *expansionType = dyn_cast<PackExpansionType>(t)) {
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auto countType = expansionType->getCountType();
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auto patternType = expansionType->getPatternType();
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auto newPatternType = transformTypeParameterPacksRec(
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patternType, fn, expansionLevel + 1);
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if (patternType.getPointer() != newPatternType.getPointer())
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return Type(PackExpansionType::get(patternType, countType));
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return Type(expansionType);
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}
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// A PackElementType with level N reaches past N levels of
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// nested PackExpansionType. So a type parameter pack reference
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// therein is free if N is greater than or equal to our current
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// expansion level.
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if (auto *eltType = dyn_cast<PackElementType>(t)) {
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if (eltType->getLevel() >= expansionLevel) {
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return transformTypeParameterPacksRec(eltType->getPackType(), fn,
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/*expansionLevel=*/0);
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}
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return Type(eltType);
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}
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// A bare type parameter pack is like a PackElementType with level 0.
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if (auto *paramType = dyn_cast<SubstitutableType>(t)) {
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if (expansionLevel == 0 && (isa<PackArchetypeType>(paramType) ||
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paramType->isRootParameterPack())) {
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return fn(paramType);
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}
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return Type(paramType);
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}
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return std::nullopt;
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});
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}
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Type Type::transformTypeParameterPacks(
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llvm::function_ref<std::optional<Type>(SubstitutableType *)> fn) const {
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return transformTypeParameterPacksRec(*this, fn, /*expansionLevel=*/0);
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}
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namespace {
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/// Collects all unique pack type parameters referenced from the pattern type,
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/// skipping those captured by nested pack expansion types.
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struct PackReferenceCollector: TypeWalker {
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llvm::function_ref<bool (Type)> fn;
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unsigned expansionLevel;
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SmallVector<unsigned, 2> elementLevel;
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PackReferenceCollector(llvm::function_ref<bool (Type)> fn)
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: fn(fn), expansionLevel(0) {
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elementLevel.push_back(0);
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}
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Action walkToTypePre(Type t) override {
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if (t->is<PackExpansionType>()) {
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++expansionLevel;
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return Action::Continue;
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}
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if (auto *boundGenericType = dyn_cast<BoundGenericType>(t.getPointer())) {
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if (auto parentType = boundGenericType->getParent())
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parentType.walk(*this);
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for (auto type : boundGenericType->getExpandedGenericArgs())
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type.walk(*this);
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return Action::SkipNode;
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}
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if (auto *typeAliasType = dyn_cast<TypeAliasType>(t.getPointer())) {
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if (typeAliasType->getDecl()->isGeneric()) {
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if (auto parentType = typeAliasType->getParent())
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parentType.walk(*this);
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for (auto type : typeAliasType->getExpandedGenericArgs())
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type.walk(*this);
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return Action::SkipNode;
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}
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}
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if (auto *eltType = t->getAs<PackElementType>()) {
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elementLevel.push_back(eltType->getLevel());
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return Action::Continue;
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}
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if (elementLevel.back() == expansionLevel) {
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if (fn(t))
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return Action::Stop;
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}
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return Action::Continue;
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}
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Action walkToTypePost(Type t) override {
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if (t->is<PackExpansionType>())
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--expansionLevel;
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if (t->is<PackElementType>())
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elementLevel.pop_back();
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return Action::Continue;
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}
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};
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}
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void TypeBase::walkPackReferences(
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llvm::function_ref<bool (Type)> fn) {
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Type(this).walk(PackReferenceCollector(fn));
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}
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void TypeBase::getTypeParameterPacks(
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SmallVectorImpl<Type> &rootParameterPacks) {
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walkPackReferences([&](Type t) {
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if (auto *paramTy = t->getAs<GenericTypeParamType>()) {
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if (paramTy->isParameterPack())
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rootParameterPacks.push_back(paramTy);
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} else if (auto *archetypeTy = t->getAs<PackArchetypeType>()) {
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if (archetypeTy->isRoot()) {
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rootParameterPacks.push_back(archetypeTy);
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} else {
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auto *genericEnv = archetypeTy->getGenericEnvironment();
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auto paramTy = archetypeTy->getInterfaceType()->getRootGenericParam();
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rootParameterPacks.push_back(
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genericEnv->mapTypeIntoContext(paramTy));
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}
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}
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return false;
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});
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}
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bool TypeBase::isParameterPack() {
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return getDependentMemberRoot()->isRootParameterPack();
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}
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bool TypeBase::isRootParameterPack() {
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Type t(this);
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return t->is<GenericTypeParamType>() &&
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t->castTo<GenericTypeParamType>()->isParameterPack();
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}
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PackType *TypeBase::getPackSubstitutionAsPackType() {
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if (auto pack = getAs<PackType>()) {
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return pack;
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} else {
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return PackType::getSingletonPackExpansion(this);
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}
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}
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static Type increasePackElementLevelImpl(
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Type type, unsigned level, unsigned outerLevel) {
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assert(level > 0);
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return type.transformRec([&](TypeBase *t) -> std::optional<Type> {
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if (auto *elementType = dyn_cast<PackElementType>(t)) {
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if (elementType->getLevel() >= outerLevel) {
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elementType = PackElementType::get(elementType->getPackType(),
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elementType->getLevel() + level);
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}
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return Type(elementType);
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}
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if (auto *expansionType = dyn_cast<PackExpansionType>(t)) {
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return Type(PackExpansionType::get(
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increasePackElementLevelImpl(expansionType->getPatternType(),
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level, outerLevel + 1),
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expansionType->getCountType()));
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}
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if (t->isParameterPack() || isa<PackArchetypeType>(t)) {
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if (outerLevel == 0)
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return Type(PackElementType::get(t, level));
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return Type(t);
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}
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return std::nullopt;
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});
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}
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Type TypeBase::increasePackElementLevel(unsigned level) {
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if (level == 0)
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return Type(this);
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return increasePackElementLevelImpl(Type(this), level, 0);
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}
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CanType PackExpansionType::getReducedShape() {
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auto reducedShape = countType->getReducedShape();
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if (reducedShape == getASTContext().TheEmptyTupleType)
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return reducedShape;
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return CanType(PackExpansionType::get(reducedShape, reducedShape));
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}
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unsigned TupleType::getNumScalarElements() const {
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unsigned n = 0;
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for (auto elt : getElements()) {
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if (!elt.getType()->is<PackExpansionType>())
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++n;
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}
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return n;
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}
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bool TupleType::containsPackExpansionType() const {
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assert(!hasTypeVariable());
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for (auto elt : getElements()) {
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auto eltTy = elt.getType();
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assert(!eltTy->hasTypeVariable());
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if (eltTy->is<PackExpansionType>())
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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 CanTupleType::containsPackExpansionTypeImpl(CanTupleType tuple) {
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for (auto eltType : tuple.getElementTypes()) {
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if (isa<PackExpansionType>(eltType))
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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 AnyFunctionType::containsPackExpansionType(ArrayRef<Param> params) {
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for (auto param : params) {
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auto paramTy = param.getPlainType();
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assert(!paramTy->hasTypeVariable());
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if (paramTy->is<PackExpansionType>())
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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 PackType::containsPackExpansionType() const {
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for (auto type : getElementTypes()) {
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if (type->is<PackExpansionType>())
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return true;
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}
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return false;
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}
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template <class T>
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static CanPackType getReducedShapeOfPack(const ASTContext &ctx,
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const T &elementTypes) {
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SmallVector<Type, 4> elts;
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elts.reserve(elementTypes.size());
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for (auto elt : elementTypes) {
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// T... => shape(T)...
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if (auto *packExpansionType = elt->template getAs<PackExpansionType>()) {
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elts.push_back(packExpansionType->getReducedShape());
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continue;
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}
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// Use () as a placeholder for scalar shape.
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elts.push_back(ctx.TheEmptyTupleType);
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}
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return CanPackType(PackType::get(ctx, elts));
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}
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CanPackType PackType::getReducedShape() {
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return getReducedShapeOfPack(getASTContext(), getElementTypes());
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}
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CanPackType SILPackType::getReducedShape() const {
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return getReducedShapeOfPack(getASTContext(), getElementTypes());
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}
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CanType TypeBase::getReducedShape() {
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if (isTypeParameter()) {
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auto *genericParam = getRootGenericParam();
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if (genericParam->isParameterPack())
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return genericParam->getCanonicalType();
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// Use () as a placeholder for scalar shape.
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return getASTContext().TheEmptyTupleType;
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}
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if (auto *packArchetype = getAs<PackArchetypeType>())
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return packArchetype->getReducedShape();
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if (auto *packType = getAs<PackType>())
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return packType->getReducedShape();
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if (auto *expansionType = getAs<PackExpansionType>())
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return expansionType->getReducedShape();
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if (auto *silPackType = getAs<SILPackType>()) {
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auto can = cast<SILPackType>(silPackType->getCanonicalType());
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return can->getReducedShape();
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}
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SmallVector<Type, 2> rootParameterPacks;
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getTypeParameterPacks(rootParameterPacks);
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if (!rootParameterPacks.empty())
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return rootParameterPacks.front()->getReducedShape();
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assert(!isTypeVariableOrMember());
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assert(!hasTypeParameter());
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// Use () as a placeholder for scalar shape.
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return getASTContext().TheEmptyTupleType;
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}
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unsigned ParameterList::getOrigParamIndex(SubstitutionMap subMap,
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unsigned substIndex) const {
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unsigned remappedIndex = substIndex;
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for (unsigned i = 0, e = size(); i < e; ++i) {
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auto *param = get(i);
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auto paramType = param->getInterfaceType();
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unsigned substCount = 1;
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if (auto *packExpansionType = paramType->getAs<PackExpansionType>()) {
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auto replacementType = packExpansionType->getCountType().subst(subMap);
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if (auto *packType = replacementType->getAs<PackType>()) {
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substCount = packType->getNumElements();
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}
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}
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if (remappedIndex < substCount)
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return i;
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remappedIndex -= substCount;
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}
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ABORT([&](auto &out) {
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out << "Invalid substituted argument index: " << substIndex << "\n";
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subMap.dump(out);
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dump(out);
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});
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}
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/// <T...> Foo<T, Pack{Int, String}> => Pack{T..., Int, String}
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SmallVector<Type, 2> BoundGenericType::getExpandedGenericArgs() {
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// It would be nicer to use genericSig.getInnermostGenericParams() here,
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// but that triggers a request cycle if we're in the middle of computing
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// the generic signature already.
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SmallVector<GenericTypeParamType *, 2> params;
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for (auto *paramDecl : getDecl()->getGenericParams()->getParams()) {
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params.push_back(paramDecl->getDeclaredInterfaceType()
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->castTo<GenericTypeParamType>());
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}
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return PackType::getExpandedGenericArgs(params, getGenericArgs());
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}
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/// <T...> Foo<T, Pack{Int, String}> => Pack{T..., Int, String}
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SmallVector<Type, 2> TypeAliasType::getExpandedGenericArgs() {
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if (!getDecl()->isGeneric())
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return SmallVector<Type, 2>();
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auto genericSig = getGenericSignature();
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return PackType::getExpandedGenericArgs(
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genericSig.getInnermostGenericParams(),
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getDirectGenericArgs());
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}
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/// <T...> Pack{T, Pack{Int, String}} => {T..., Int, String}
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SmallVector<Type, 2>
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PackType::getExpandedGenericArgs(ArrayRef<GenericTypeParamType *> params,
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ArrayRef<Type> args) {
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SmallVector<Type, 2> wrappedArgs;
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assert(params.size() == args.size());
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for (unsigned i = 0, e = params.size(); i < e; ++i) {
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auto arg = args[i];
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if (params[i]->isParameterPack()) {
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// FIXME: A temporary fix to make it possible to debug expressions
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// with partially resolved variadic generic types. The issue stems
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// from the fact that `BoundGenericType` is allowed to have pack
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// parameters directly represented by type variables, as soon as
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// that is no longer the case this check should be removed.
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if (arg->is<TypeVariableType>()) {
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wrappedArgs.push_back(arg);
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} else {
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auto argPackElements = arg->castTo<PackType>()->getElementTypes();
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wrappedArgs.append(argPackElements.begin(), argPackElements.end());
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}
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continue;
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}
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wrappedArgs.push_back(arg);
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}
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return wrappedArgs;
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}
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PackType *PackType::getSingletonPackExpansion(Type param) {
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SmallVector<Type, 2> rootParameterPacks;
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param->getTypeParameterPacks(rootParameterPacks);
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assert(rootParameterPacks.size() >= 1);
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auto count = rootParameterPacks[0];
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return get(param->getASTContext(), {PackExpansionType::get(param, count)});
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}
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CanPackType CanPackType::getSingletonPackExpansion(CanType param) {
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// Note: You can't just wrap the result in CanPackType() here because
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// PackExpansionType has the additional requirement that the count type
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// must be a reduced shape.
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return cast<PackType>(
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PackType::getSingletonPackExpansion(param)
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->getCanonicalType());
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}
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PackExpansionType *PackType::unwrapSingletonPackExpansion() const {
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if (getNumElements() == 1) {
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if (auto expansion = getElementTypes()[0]->getAs<PackExpansionType>()) {
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auto pattern = expansion->getPatternType();
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if (pattern->isParameterPack() || pattern->is<PackArchetypeType>())
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return expansion;
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}
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}
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return nullptr;
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}
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bool SILPackType::containsPackExpansionType() const {
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for (auto type : getElementTypes()) {
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if (isa<PackExpansionType>(type))
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return true;
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}
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return false;
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}
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CanPackType
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CanTupleType::getInducedPackTypeImpl(CanTupleType tuple) {
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return getInducedPackTypeImpl(tuple, 0, tuple->getNumElements());
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}
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CanPackType
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CanTupleType::getInducedPackTypeImpl(CanTupleType tuple, unsigned start, unsigned count) {
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assert(start + count <= tuple->getNumElements() && "range out of range");
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auto &ctx = tuple->getASTContext();
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return CanPackType::get(ctx, tuple.getElementTypes().slice(start, count));
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}
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static CanType getApproximateFormalElementType(const ASTContext &ctx,
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CanType loweredEltType) {
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CanType formalEltType = TupleType::getEmpty(ctx);
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if (auto expansion = dyn_cast<PackExpansionType>(loweredEltType))
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formalEltType = CanPackExpansionType::get(formalEltType,
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expansion.getCountType());
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return formalEltType;
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}
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template <class Collection>
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static CanPackType getApproximateFormalPackType(const ASTContext &ctx,
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Collection loweredEltTypes) {
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// Build an array of formal element types, but be lazy about it:
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// use the original array unless we see an element type that doesn't
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// work as a legal formal type.
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std::optional<SmallVector<CanType, 4>> formalEltTypes;
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for (auto i : indices(loweredEltTypes)) {
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auto loweredEltType = loweredEltTypes[i];
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bool isLegal = loweredEltType->isLegalFormalType();
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// If the type isn't legal as a formal type, substitute the empty
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// tuple type (or an invariant expansion of it over the count type).
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CanType formalEltType = loweredEltType;
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if (!isLegal) {
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formalEltType = getApproximateFormalElementType(ctx, loweredEltType);
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}
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// If we're already building an array, unconditionally append to it.
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// Otherwise, if the type isn't legal, build the array up to this
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// point and then append. Otherwise, we're still being lazy.
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if (formalEltTypes) {
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formalEltTypes->push_back(formalEltType);
|
|
} else if (!isLegal) {
|
|
formalEltTypes.emplace();
|
|
formalEltTypes->reserve(loweredEltTypes.size());
|
|
formalEltTypes->append(loweredEltTypes.begin(),
|
|
loweredEltTypes.begin() + i);
|
|
formalEltTypes->push_back(formalEltType);
|
|
}
|
|
|
|
assert(isLegal || formalEltTypes.has_value());
|
|
}
|
|
|
|
// Use the array we built if we made one (if we ever saw a non-legal
|
|
// element type).
|
|
if (formalEltTypes) {
|
|
return CanPackType::get(ctx, *formalEltTypes);
|
|
} else {
|
|
return CanPackType::get(ctx, loweredEltTypes);
|
|
}
|
|
}
|
|
|
|
CanPackType SILPackType::getApproximateFormalPackType() const {
|
|
return ::getApproximateFormalPackType(getASTContext(), getElementTypes());
|
|
}
|
|
|
|
CanPackType
|
|
CanTupleType::getInducedApproximateFormalPackTypeImpl(CanTupleType tuple) {
|
|
return ::getApproximateFormalPackType(tuple->getASTContext(),
|
|
tuple.getElementTypes());
|
|
}
|