Factor conformance attributes into their own separate structure.

We had an exploded form of conformance attributes (@unchecked,
@preconcurrency, @unsafe) at several different places in the compiler.
Pull these into a single structure so it's easier to manage and extend.

Should have done this a long time ago.

Author: DougGregor

include/swift/AST/ConformanceAttributes.h

@@ -0,0 +1,46 @@
+//===--- ConformanceLookup.h - Global conformance lookup --------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2024 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_AST_CONFORMANCEATTRIBUTES_H
+#define SWIFT_AST_CONFORMANCEATTRIBUTES_H
+
+#include "swift/Basic/SourceLoc.h"
+
+namespace swift {
+
+/// Describes all of the attributes that can occur on a conformance.
+struct ConformanceAttributes {
+  /// The location of the "unchecked" attribute, if present.
+  SourceLoc uncheckedLoc;
+
+  /// The location of the "preconcurrency" attribute if present.
+  SourceLoc preconcurrencyLoc;
+
+  /// The location of the "unsafe" attribute if present.
+  SourceLoc unsafeLoc;
+  
+  /// Merge other conformance attributes into this set.
+  ConformanceAttributes &
+  operator |=(const ConformanceAttributes &other) {
+    if (other.uncheckedLoc.isValid())
+      uncheckedLoc = other.uncheckedLoc;
+    if (other.preconcurrencyLoc.isValid())
+      preconcurrencyLoc = other.preconcurrencyLoc;
+    if (other.unsafeLoc.isValid())
+      unsafeLoc = other.unsafeLoc;
+    return *this;
+  }
+};
+
+}
+
+#endif

include/swift/AST/NameLookup.h

@@ -19,6 +19,7 @@
 
 #include "swift/AST/ASTVisitor.h"
 #include "swift/AST/CatchNode.h"
+#include "swift/AST/ConformanceAttributes.h"
 #include "swift/AST/GenericSignature.h"
 #include "swift/AST/Identifier.h"
 #include "swift/AST/Module.h"
@@ -603,25 +604,17 @@ void forEachPotentialAttachedMacro(
 
 /// Describes an inherited nominal entry.
 struct InheritedNominalEntry : Located<NominalTypeDecl *> {
-  /// The location of the "unchecked" attribute, if present.
-  SourceLoc uncheckedLoc;
-
-  /// The location of the "preconcurrency" attribute if present.
-  SourceLoc preconcurrencyLoc;
-
-  /// The location of the "unsafe" attribute if present.
-  SourceLoc unsafeLoc;
+  ConformanceAttributes attributes;
 
   /// Whether this inherited entry was suppressed via "~".
   bool isSuppressed;
 
   InheritedNominalEntry() { }
 
   InheritedNominalEntry(NominalTypeDecl *item, SourceLoc loc,
-                        SourceLoc uncheckedLoc, SourceLoc preconcurrencyLoc,
-                        SourceLoc unsafeLoc, bool isSuppressed)
-      : Located(item, loc), uncheckedLoc(uncheckedLoc),
-        preconcurrencyLoc(preconcurrencyLoc), unsafeLoc(unsafeLoc),
+                        ConformanceAttributes attributes,
+                        bool isSuppressed)
+      : Located(item, loc), attributes(attributes),
         isSuppressed(isSuppressed) {}
 };
 

lib/AST/ConformanceLookupTable.cpp

@@ -16,6 +16,7 @@
 
 #include "ConformanceLookupTable.h"
 #include "swift/AST/ASTContext.h"
+#include "swift/AST/ConformanceAttributes.h"
 #include "swift/AST/ConformanceLookup.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/ExistentialLayout.h"
@@ -148,23 +149,13 @@ void ConformanceLookupTable::destroy() {
 
 namespace {
   struct ConformanceConstructionInfo : public Located<ProtocolDecl *> {
-    /// The location of the "unchecked" attribute, if present.
-    const SourceLoc uncheckedLoc;
-
-    /// The location of the "preconcurrency" attribute if present.
-    const SourceLoc preconcurrencyLoc;
-
-    /// The location of the "unsafe" attribute if present.
-    const SourceLoc unsafeLoc;
+    ConformanceAttributes attributes;
 
     ConformanceConstructionInfo() { }
 
     ConformanceConstructionInfo(ProtocolDecl *item, SourceLoc loc,
-                                SourceLoc uncheckedLoc,
-                                SourceLoc preconcurrencyLoc,
-                                SourceLoc unsafeLoc)
-        : Located(item, loc), uncheckedLoc(uncheckedLoc),
-          preconcurrencyLoc(preconcurrencyLoc), unsafeLoc(unsafeLoc) {}
+                                ConformanceAttributes attributes)
+        : Located(item, loc), attributes(attributes) {}
   };
 }
 
@@ -220,7 +211,7 @@ void ConformanceLookupTable::forEachInStage(ConformanceStage stage,
       registerProtocolConformances(next, conformances);
       for (auto conf : conformances) {
         protocols.push_back(
-            {conf->getProtocol(), SourceLoc(), SourceLoc(), SourceLoc(), SourceLoc()});
+            {conf->getProtocol(), SourceLoc(), ConformanceAttributes()});
       }
     } else if (next->getParentSourceFile() ||
                next->getParentModule()->isBuiltinModule()) {
@@ -229,9 +220,7 @@ void ConformanceLookupTable::forEachInStage(ConformanceStage stage,
       for (const auto &found :
                getDirectlyInheritedNominalTypeDecls(next, inverses, anyObject)) {
         if (auto proto = dyn_cast<ProtocolDecl>(found.Item))
-          protocols.push_back(
-              {proto, found.Loc, found.uncheckedLoc,
-               found.preconcurrencyLoc, found.unsafeLoc});
+          protocols.push_back({proto, found.Loc, found.attributes});
       }
     }
 
@@ -318,10 +307,8 @@ void ConformanceLookupTable::updateLookupTable(NominalTypeDecl *nominal,
                   kp.has_value() &&
                       "suppressed conformance for non-known protocol!?");
             if (!found.isSuppressed) {
-              addProtocol(proto, found.Loc,
-                          source.withUncheckedLoc(found.uncheckedLoc)
-                                .withPreconcurrencyLoc(found.preconcurrencyLoc)
-                                .withUnsafeLoc(found.unsafeLoc));
+              addProtocol(
+                  proto, found.Loc, source.withAttributes(found.attributes));
             }
           }
 
@@ -335,9 +322,7 @@ void ConformanceLookupTable::updateLookupTable(NominalTypeDecl *nominal,
           for (auto locAndProto : protos)
             addProtocol(
                 locAndProto.Item, locAndProto.Loc,
-                source.withUncheckedLoc(locAndProto.uncheckedLoc)
-                      .withPreconcurrencyLoc(locAndProto.preconcurrencyLoc)
-                      .withUnsafeLoc(locAndProto.unsafeLoc));
+                source.withAttributes(locAndProto.attributes));
         });
     break;
 

lib/AST/ConformanceLookupTable.h

@@ -21,6 +21,7 @@
 #define SWIFT_AST_CONFORMANCE_LOOKUP_TABLE_H
 
 #include "swift/AST/DeclContext.h"
+#include "swift/AST/ConformanceAttributes.h"
 #include "swift/AST/ProtocolConformanceOptions.h"
 #include "swift/Basic/Debug.h"
 #include "swift/Basic/LLVM.h"
@@ -89,14 +90,7 @@ class ConformanceLookupTable : public ASTAllocated<ConformanceLookupTable> {
 
     ConformanceEntryKind Kind;
 
-    /// The location of the "unchecked" attribute, if there is one.
-    SourceLoc uncheckedLoc;
-
-    /// The location of the "preconcurrency" attribute, if there is one.
-    SourceLoc preconcurrencyLoc;
-
-    /// The location of the "unsafe" attribute, if there is one.
-    SourceLoc unsafeLoc;
+    ConformanceAttributes attributes;
 
     ConformanceSource(void *ptr, ConformanceEntryKind kind)
       : Storage(ptr), Kind(kind) { }
@@ -140,29 +134,16 @@ class ConformanceLookupTable : public ASTAllocated<ConformanceLookupTable> {
       return ConformanceSource(dc, ConformanceEntryKind::PreMacroExpansion);
     }
 
-    /// Return a new conformance source with the given location of "@unchecked".
-    ConformanceSource withUncheckedLoc(SourceLoc uncheckedLoc) {
-      ConformanceSource result(*this);
-      if (uncheckedLoc.isValid())
-        result.uncheckedLoc = uncheckedLoc;
-      return result;
-    }
-
-    /// Return a new conformance source with the given location of
-    /// "@preconcurrency".
-    ConformanceSource withPreconcurrencyLoc(SourceLoc preconcurrencyLoc) {
+    /// Return a new conformance source with the given conformance
+    /// attributes.
+    ConformanceSource withAttributes(ConformanceAttributes attributes) {
       ConformanceSource result(*this);
-      if (preconcurrencyLoc.isValid())
-        result.preconcurrencyLoc = preconcurrencyLoc;
+      result.attributes |= attributes;
       return result;
     }
 
-    /// Return a new conformance source with the given location of "@unsafe".
-    ConformanceSource withUnsafeLoc(SourceLoc unsafeLoc) {
-      ConformanceSource result(*this);
-      if (unsafeLoc.isValid())
-        result.unsafeLoc = unsafeLoc;
-      return result;
+    ConformanceAttributes getAttributes() const {
+      return attributes;
     }
 
     ProtocolConformanceOptions getOptions() const {
@@ -216,16 +197,16 @@ class ConformanceLookupTable : public ASTAllocated<ConformanceLookupTable> {
 
     /// The location of the @unchecked attribute, if any.
     SourceLoc getUncheckedLoc() const {
-      return uncheckedLoc;
+      return attributes.uncheckedLoc;
     }
 
     SourceLoc getPreconcurrencyLoc() const {
-      return preconcurrencyLoc;
+      return attributes.preconcurrencyLoc;
     }
 
     /// The location of the @unsafe attribute, if any.
     SourceLoc getUnsafeLoc() const {
-      return unsafeLoc;
+      return attributes.unsafeLoc;
     }
 
     /// For an inherited conformance, retrieve the class declaration

lib/AST/NameLookup.cpp

@@ -19,6 +19,7 @@
 #include "swift/AST/ASTVisitor.h"
 #include "swift/AST/ASTWalker.h"
 #include "swift/AST/ClangModuleLoader.h"
+#include "swift/AST/ConformanceAttributes.h"
 #include "swift/AST/DebuggerClient.h"
 #include "swift/AST/ExistentialLayout.h"
 #include "swift/AST/GenericParamList.h"
@@ -3962,23 +3963,19 @@ void swift::getDirectlyInheritedNominalTypeDecls(
   // FIXME: This is a hack. We need cooperation from
   // InheritedDeclsReferencedRequest to make this work.
   SourceLoc loc;
-  SourceLoc uncheckedLoc;
-  SourceLoc preconcurrencyLoc;
-  SourceLoc unsafeLoc;
+  ConformanceAttributes attributes;
   auto inheritedTypes = InheritedTypes(decl);
   bool isSuppressed = inheritedTypes.getEntry(i).isSuppressed();
   if (TypeRepr *typeRepr = inheritedTypes.getTypeRepr(i)) {
     loc = typeRepr->getLoc();
-    uncheckedLoc = typeRepr->findAttrLoc(TypeAttrKind::Unchecked);
-    preconcurrencyLoc = typeRepr->findAttrLoc(TypeAttrKind::Preconcurrency);
-    unsafeLoc = typeRepr->findAttrLoc(TypeAttrKind::Unsafe);
+    attributes.uncheckedLoc = typeRepr->findAttrLoc(TypeAttrKind::Unchecked);
+    attributes.preconcurrencyLoc = typeRepr->findAttrLoc(TypeAttrKind::Preconcurrency);
+    attributes.unsafeLoc = typeRepr->findAttrLoc(TypeAttrKind::Unsafe);
   }
 
   // Form the result.
   for (auto nominal : nominalTypes) {
-    result.push_back(
-        {nominal, loc, uncheckedLoc, preconcurrencyLoc, unsafeLoc,
-          isSuppressed});
+    result.push_back({nominal, loc, attributes, isSuppressed});
   }
 }
 
@@ -4008,10 +4005,11 @@ swift::getDirectlyInheritedNominalTypeDecls(
   for (auto attr :
        protoDecl->getAttrs().getAttributes<SynthesizedProtocolAttr>()) {
     auto loc = attr->getLocation();
+    ConformanceAttributes attributes;
+    if (attr->isUnchecked())
+      attributes.uncheckedLoc = loc;
     result.push_back(
-        {attr->getProtocol(), loc, attr->isUnchecked() ? loc : SourceLoc(),
-         /*preconcurrencyLoc=*/SourceLoc(), SourceLoc(),
-          /*isSuppressed=*/false});
+        {attr->getProtocol(), loc, attributes, /*isSuppressed=*/false});
   }
 
   // Else we have access to this information on the where clause.
@@ -4022,8 +4020,8 @@ swift::getDirectlyInheritedNominalTypeDecls(
   // FIXME: Refactor SelfBoundsFromWhereClauseRequest to dig out
   // the source location.
   for (auto inheritedNominal : selfBounds.decls)
-    result.emplace_back(inheritedNominal, SourceLoc(), SourceLoc(),
-                        SourceLoc(), SourceLoc(),  /*isSuppressed=*/false);
+    result.emplace_back(inheritedNominal, SourceLoc(), ConformanceAttributes(),
+                        /*isSuppressed=*/false);
 
   return result;
 }