AST: Introduce representation for pack conformances

Author: slavapestov

include/swift/AST/PackConformance.h

@@ -0,0 +1,95 @@
+//===--- PackConformance.h - Variadic Protocol Conformance ------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2022 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the PackConformance structure, which describes the
+// conformance of a type pack parameter to a protocol.
+//
+//===----------------------------------------------------------------------===//
+#ifndef SWIFT_AST_PACKCONFORMANCE_H
+#define SWIFT_AST_PACKCONFORMANCE_H
+
+#include "swift/AST/ASTAllocated.h"
+#include "swift/AST/ProtocolConformanceRef.h"
+#include "swift/AST/Type.h"
+#include "swift/AST/TypeAlignments.h"
+#include "swift/Basic/Compiler.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/FoldingSet.h"
+#include "llvm/Support/TrailingObjects.h"
+
+namespace swift {
+
+class PackType;
+
+class alignas(1 << DeclAlignInBits) PackConformance final
+  : public ASTAllocated<PackConformance>,
+    public llvm::FoldingSetNode,
+    private llvm::TrailingObjects<PackConformance, ProtocolConformanceRef> {
+  friend class ASTContext;
+  friend TrailingObjects;
+
+  /// The pack type conforming to the protocol.
+  PackType *ConformingType;
+
+  /// The conformed-to protocol.
+  ProtocolDecl *Protocol;
+
+public:
+  void Profile(llvm::FoldingSetNodeID &ID) const;
+  static void Profile(llvm::FoldingSetNodeID &ID,
+                      PackType *conformingType,
+                      ProtocolDecl *protocol,
+                      ArrayRef<ProtocolConformanceRef> conformances);
+
+private:
+  PackConformance(PackType *conformingType,
+                  ProtocolDecl *protocol,
+                  ArrayRef<ProtocolConformanceRef> conformances);
+
+  size_t numTrailingObjects(OverloadToken<ProtocolConformanceRef>) const;
+
+public:
+  static PackConformance *get(PackType *conformingType,
+                              ProtocolDecl *protocol,
+                              ArrayRef<ProtocolConformanceRef> conformances);
+
+  PackType *getType() const { return ConformingType; }
+
+  ProtocolDecl *getProtocol() const { return Protocol; }
+
+  ArrayRef<ProtocolConformanceRef> getPatternConformances() const;
+
+  bool isCanonical() const;
+
+  PackConformance *getCanonicalConformance() const;
+
+  PackType *getAssociatedType(Type assocType) const;
+
+  PackConformance *
+  getAssociatedConformance(Type assocType, ProtocolDecl *protocol) const;
+
+  PackConformance *subst(SubstitutionMap subMap,
+                         SubstOptions options=None) const;
+
+  PackConformance *subst(TypeSubstitutionFn subs,
+                         LookupConformanceFn conformances,
+                         SubstOptions options=None) const;
+
+  SWIFT_DEBUG_DUMP;
+  void dump(llvm::raw_ostream &out, unsigned indent = 0) const;
+};
+
+void simple_display(llvm::raw_ostream &out, PackConformance *conformance);
+
+} // end namespace swift
+
+#endif  // SWIFT_AST_PACKCONFORMANCE_H

include/swift/AST/TypeAlignments.h

@@ -46,6 +46,7 @@ namespace swift {
   class NormalProtocolConformance;
   class OpaqueValueExpr;
   class OperatorDecl;
+  class PackConformance;
   class Pattern;
   class ProtocolDecl;
   class ProtocolConformance;
@@ -133,6 +134,7 @@ LLVM_DECLARE_TYPE_ALIGNMENT(swift::Expr, swift::ExprAlignInBits)
 LLVM_DECLARE_TYPE_ALIGNMENT(swift::CaptureListExpr, swift::ExprAlignInBits)
 LLVM_DECLARE_TYPE_ALIGNMENT(swift::AbstractClosureExpr, swift::ExprAlignInBits)
 LLVM_DECLARE_TYPE_ALIGNMENT(swift::OpaqueValueExpr, swift::ExprAlignInBits)
+LLVM_DECLARE_TYPE_ALIGNMENT(swift::PackConformance, swift::DeclAlignInBits)
 LLVM_DECLARE_TYPE_ALIGNMENT(swift::ProtocolConformance, swift::DeclAlignInBits)
 LLVM_DECLARE_TYPE_ALIGNMENT(swift::NormalProtocolConformance,
                             swift::DeclAlignInBits)

lib/AST/ASTContext.cpp

@@ -37,6 +37,7 @@
 #include "swift/AST/ModuleDependencies.h"
 #include "swift/AST/ModuleLoader.h"
 #include "swift/AST/NameLookup.h"
+#include "swift/AST/PackConformance.h"
 #include "swift/AST/ParameterList.h"
 #include "swift/AST/PrettyStackTrace.h"
 #include "swift/AST/PropertyWrappers.h"
@@ -445,6 +446,9 @@ struct ASTContext::Implementation {
     llvm::DenseMap<std::pair<Type, ProtocolDecl *>,
                    BuiltinProtocolConformance *> BuiltinConformances;
 
+    /// The set of pack conformances.
+    llvm::FoldingSet<PackConformance> PackConformances;
+
     /// The set of substitution maps (uniqued by their storage).
     llvm::FoldingSet<SubstitutionMap::Storage> SubstitutionMaps;
 
@@ -2473,6 +2477,48 @@ ASTContext::getInheritedConformance(Type type, ProtocolConformance *inherited) {
   return result;
 }
 
+PackConformance *PackConformance::get(PackType *conformingType,
+                                      ProtocolDecl *protocol,
+                                      ArrayRef<ProtocolConformanceRef> conformances) {
+  auto properties = conformingType->getRecursiveProperties();
+
+  for (auto conformance : conformances) {
+    if (conformance.isAbstract() || conformance.isInvalid())
+      continue;
+
+    auto *concrete = conformance.getConcrete();
+    properties |= concrete->getType()->getRecursiveProperties();
+  }
+
+  auto &ctx = protocol->getASTContext();
+
+  llvm::FoldingSetNodeID id;
+  PackConformance::Profile(id, conformingType, protocol, conformances);
+
+  // Figure out which arena this conformance should go into.
+  AllocationArena arena = getArena(properties);
+
+  // Did we already record the pack conformance?
+  void *insertPos;
+  auto &packConformances = ctx.getImpl().getArena(arena).PackConformances;
+  if (auto result = packConformances.FindNodeOrInsertPos(id, insertPos))
+    return result;
+
+  // Build a new pack conformance.
+  auto size = totalSizeToAlloc<ProtocolConformanceRef>(conformances.size());
+  auto mem = ctx.Allocate(size, alignof(PackConformance), arena);
+
+  auto result
+    = new (mem) PackConformance(conformingType, protocol,
+                                conformances);
+  auto node = packConformances.FindNodeOrInsertPos(id, insertPos);
+  (void)node;
+  assert(!node);
+  packConformances.InsertNode(result, insertPos);
+
+  return result;
+}
+
 LazyContextData *ASTContext::getOrCreateLazyContextData(
                                                 const DeclContext *dc,
                                                 LazyMemberLoader *lazyLoader) {

lib/AST/ASTDumper.cpp

@@ -23,6 +23,7 @@
 #include "swift/AST/ForeignErrorConvention.h"
 #include "swift/AST/GenericEnvironment.h"
 #include "swift/AST/Initializer.h"
+#include "swift/AST/PackConformance.h"
 #include "swift/AST/ParameterList.h"
 #include "swift/AST/ProtocolConformance.h"
 #include "swift/AST/SourceFile.h"
@@ -3404,6 +3405,27 @@ static void dumpProtocolConformanceRec(
   PrintWithColorRAII(out, ParenthesisColor) << ')';
 }
 
+static void dumpPackConformanceRec(
+    const PackConformance *conformance, llvm::raw_ostream &out,
+    unsigned indent,
+    llvm::SmallPtrSetImpl<const ProtocolConformance *> &visited) {
+  out.indent(indent);
+  PrintWithColorRAII(out, ParenthesisColor) << '(';
+  out << "pack_conformance type=" << Type(conformance->getType())
+      << " protocol=" << conformance->getProtocol()->getName();
+
+  auto conformances = conformance->getPatternConformances();
+  if (!conformances.empty()) {
+    out << "\n";
+
+    for (auto conformanceRef : conformances) {
+      dumpProtocolConformanceRefRec(conformanceRef, out, indent, visited);
+    }
+  }
+
+  PrintWithColorRAII(out, ParenthesisColor) << ')';
+}
+
 static void dumpSubstitutionMapRec(
     SubstitutionMap map, llvm::raw_ostream &out,
     SubstitutionMap::DumpStyle style, unsigned indent,
@@ -3501,6 +3523,11 @@ void ProtocolConformance::dump(llvm::raw_ostream &out, unsigned indent) const {
   dumpProtocolConformanceRec(this, out, indent, visited);
 }
 
+void PackConformance::dump(llvm::raw_ostream &out, unsigned indent) const {
+  llvm::SmallPtrSet<const ProtocolConformance *, 8> visited;
+  dumpPackConformanceRec(this, out, indent, visited);
+}
+
 void SubstitutionMap::dump(llvm::raw_ostream &out, DumpStyle style,
                            unsigned indent) const {
   llvm::SmallPtrSet<const ProtocolConformance *, 8> visited;

lib/AST/CMakeLists.txt

@@ -69,6 +69,7 @@ add_swift_host_library(swiftAST STATIC
   NameLookup.cpp
   NameLookupRequests.cpp
   OperatorNameLookup.cpp
+  PackConformance.cpp
   Parameter.cpp
   Pattern.cpp
   PlatformKind.cpp