[Macros] Factor out iteration over all attached macro attributes of a particular

role into `Decl::forEachAttachedMacro`.

Author: hborla

include/swift/AST/Decl.h

@@ -80,6 +80,7 @@ namespace swift {
   class GenericSignature;
   class GenericTypeParamDecl;
   class GenericTypeParamType;
+  class MacroDecl;
   class MacroDefinition;
   class ModuleDecl;
   class NamedPattern;
@@ -856,6 +857,13 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl> {
   /// attribute macro expansion.
   DeclAttributes getSemanticAttrs() const;
 
+  using MacroCallback = llvm::function_ref<void(CustomAttr *, MacroDecl *)>;
+
+  /// Iterate over each attached macro with the given role, invoking the
+  /// given callback with each macro custom attribute and corresponding macro
+  /// declaration.
+  void forEachAttachedMacro(MacroRole role, MacroCallback) const;
+
   /// Returns the innermost enclosing decl with an availability annotation.
   const Decl *getInnermostDeclWithAvailability() const;
 

lib/AST/Decl.cpp

@@ -374,6 +374,28 @@ DeclAttributes Decl::getSemanticAttrs() const {
   return getAttrs();
 }
 
+void Decl::forEachAttachedMacro(MacroRole role,
+                                MacroCallback macroCallback) const {
+  auto *dc = getDeclContext();
+  auto &ctx = dc->getASTContext();
+
+  for (auto customAttrConst : getSemanticAttrs().getAttributes<CustomAttr>()) {
+    auto customAttr = const_cast<CustomAttr *>(customAttrConst);
+    auto *macroDecl = evaluateOrDefault(
+        ctx.evaluator,
+        ResolveAttachedMacroRequest{customAttr, dc},
+        nullptr);
+
+    if (!macroDecl)
+      continue;
+
+    if (!macroDecl->getMacroRoles().contains(role))
+      continue;
+
+    macroCallback(customAttr, macroDecl);
+  }
+}
+
 const Decl *Decl::getInnermostDeclWithAvailability() const {
   const Decl *enclosingDecl = this;
   // Find the innermost enclosing declaration with an @available annotation.

lib/Sema/TypeCheckMacros.cpp

@@ -316,51 +316,21 @@ bool ExpandMemberAttributeMacros::evaluate(Evaluator &evaluator,
     return false;
 
   bool addedAttributes = false;
-  auto parentAttrs = parentDecl->getSemanticAttrs();
-  for (auto customAttrConst: parentAttrs.getAttributes<CustomAttr>()) {
-    auto customAttr = const_cast<CustomAttr *>(customAttrConst);
-    auto *macroDecl = evaluateOrDefault(
-        evaluator,
-          ResolveAttachedMacroRequest{
-          customAttr,
-          parentDecl->getInnermostDeclContext()
-        },
-        nullptr);
-
-    if (!macroDecl)
-      continue;
-
-    if (!macroDecl->getMacroRoles().contains(MacroRole::MemberAttribute))
-      continue;
-
-    addedAttributes |= expandAttributes(customAttr, macroDecl, decl);
-  }
+  parentDecl->forEachAttachedMacro(MacroRole::MemberAttribute,
+      [&](CustomAttr *attr, MacroDecl *macro) {
+        addedAttributes |= expandAttributes(attr, macro, decl);
+      });
 
   return addedAttributes;
 }
 
 bool ExpandSynthesizedMemberMacroRequest::evaluate(Evaluator &evaluator,
                                                    Decl *decl) const {
-  auto &ctx = decl->getASTContext();
-  auto *dc = decl->getInnermostDeclContext();
   bool synthesizedMembers = false;
-
-  for (auto customAttrConst : decl->getSemanticAttrs().getAttributes<CustomAttr>()) {
-    auto customAttr = const_cast<CustomAttr *>(customAttrConst);
-    auto *macroDecl = evaluateOrDefault(
-        ctx.evaluator,
-        ResolveAttachedMacroRequest{customAttr, dc},
-        nullptr);
-
-    if (!macroDecl)
-      continue;
-
-    if (!macroDecl->getMacroRoles().contains(MacroRole::SynthesizedMembers))
-      continue;
-
-    // Expand the synthesized members.
-    synthesizedMembers |= expandSynthesizedMembers(customAttr, macroDecl, decl);
-  }
+  decl->forEachAttachedMacro(MacroRole::SynthesizedMembers,
+      [&](CustomAttr *attr, MacroDecl *macro) {
+        synthesizedMembers |= expandSynthesizedMembers(attr, macro, decl);
+      });
 
   return synthesizedMembers;
 }

lib/Sema/TypeCheckStorage.cpp

@@ -3447,26 +3447,11 @@ StorageImplInfoRequest::evaluate(Evaluator &evaluator,
     return info;
   }
 
-  // Check for an accessor macro.
-  for (auto customAttrConst : storage->getSemanticAttrs().getAttributes<CustomAttr>()) {
-    auto customAttr = const_cast<CustomAttr *>(customAttrConst);
-    auto *macro = evaluateOrDefault(
-        evaluator,
-        ResolveAttachedMacroRequest{
-          customAttr,
-          storage->getInnermostDeclContext()
-        },
-        nullptr);
-
-    if (!macro)
-      continue;
-
-    if (!macro->getMacroRoles().contains(MacroRole::Accessor))
-      continue;
-
-    // Expand the accessors.
-    expandAccessors(storage, customAttr, macro);
-  }
+  // Expand any attached accessor macros.
+  storage->forEachAttachedMacro(MacroRole::Accessor,
+      [&](CustomAttr *customAttr, MacroDecl *macro) {
+        expandAccessors(storage, customAttr, macro);
+      });
 
   bool hasWillSet = storage->getParsedAccessor(AccessorKind::WillSet);
   bool hasDidSet = storage->getParsedAccessor(AccessorKind::DidSet);