Merge pull request #36198 from beccadax/a-swift-by-any-other-name-would-warn-as-bleat

Fix rebranch SwiftNameAttr warning regression

Author: beccadax

lib/ClangImporter/ClangImporter.cpp

@@ -391,9 +391,7 @@ void ClangImporter::Implementation::addBridgeHeaderTopLevelDecls(
   BridgeHeaderTopLevelDecls.push_back(D);
 }
 
-bool ClangImporter::Implementation::shouldIgnoreBridgeHeaderTopLevelDecl(
-    clang::Decl *D) {
-  // Ignore forward references;
+bool importer::isForwardDeclOfType(const clang::Decl *D) {
   if (auto *ID = dyn_cast<clang::ObjCInterfaceDecl>(D)) {
     if (!ID->isThisDeclarationADefinition())
       return true;
@@ -407,6 +405,11 @@ bool ClangImporter::Implementation::shouldIgnoreBridgeHeaderTopLevelDecl(
   return false;
 }
 
+bool ClangImporter::Implementation::shouldIgnoreBridgeHeaderTopLevelDecl(
+    clang::Decl *D) {
+  return importer::isForwardDeclOfType(D);
+}
+
 ClangImporter::ClangImporter(ASTContext &ctx,
                              DependencyTracker *tracker,
                              DWARFImporterDelegate *dwarfImporterDelegate)

lib/ClangImporter/ImporterImpl.h

@@ -1462,6 +1462,10 @@ class LLVM_LIBRARY_VISIBILITY ClangImporter::Implementation
 
 namespace importer {
 
+/// Whether this is a forward declaration of a type. We ignore forward
+/// declarations in certain cases, and instead process the real declarations.
+bool isForwardDeclOfType(const clang::Decl *decl);
+
 /// Whether we should suppress the import of the given Clang declaration.
 bool shouldSuppressDeclImport(const clang::Decl *decl);
 

lib/ClangImporter/SwiftLookupTable.cpp

@@ -2039,7 +2039,12 @@ void importer::finalizeLookupTable(
       auto decl = entry.get<clang::NamedDecl *>();
       auto swiftName = decl->getAttr<clang::SwiftNameAttr>();
 
-      if (swiftName) {
+      if (swiftName
+          // Clang didn't previously attach SwiftNameAttrs to forward
+          // declarations, but this changed and we started diagnosing spurious
+          // warnings on @class declarations. Suppress them.
+          // FIXME: Can we avoid processing these decls in the first place?
+          && !importer::isForwardDeclOfType(decl)) {
         clang::SourceLocation diagLoc = swiftName->getLocation();
         if (!diagLoc.isValid())
           diagLoc = decl->getLocation();

test/ClangImporter/Inputs/custom-modules/ImportAsMember.apinotes

@@ -1,4 +1,7 @@
 Name: ImportAsMember
+Classes:
+- Name: IAMPrivateChild
+  SwiftName: IAMPrivateParent.Child
 Globals:
 - Name: IAMStruct1APINoteVar
   SwiftName: Struct1.newApiNoteVar

test/ClangImporter/Inputs/custom-modules/ImportAsMember.h

@@ -76,4 +76,9 @@ typedef int IAMBadInnerIntAPINotes;
 // CHECK: ImportAsMember.h:[[@LINE-1]]:{{[0-9]+}}: warning: imported declaration 'IAMBadInnerIntAPINotes' could not be mapped to 'IAMNonexistent.Inner2'
 // CHECK: ImportAsMember.h:[[@LINE-2]]:{{[0-9]+}}: note: please report this issue to the owners of 'ImportAsMember'
 
+@interface IAMPrivateParent @end
+@interface IAMPrivateChild
+- (instancetype)init;
+@end
+
 #endif // IMPORT_AS_MEMBER_H

test/ClangImporter/Inputs/custom-modules/ImportAsMember_Private.h

@@ -0,0 +1,9 @@
+#ifndef IMPORT_AS_MEMBER_PRIVATE_H
+#define IMPORT_AS_MEMBER_PRIVATE_H
+
+#include <ImportAsMember.h>
+
+@class IAMPrivateChild;
+// CHECK-NOT: ImportAsMember_Private.h:[[@LINE-1]]:{{[0-9]+}}: warning: imported declaration 'IAMPrivateChild' could not be mapped to 'IAMPrivateParent.Child'
+
+#endif // IMPORT_AS_MEMBER_PRIVATE_H

test/ClangImporter/Inputs/custom-modules/module.map

@@ -113,6 +113,16 @@ module ImportAsMember {
   }
 }
 
+// FIXME: This probably ought to be in a module_private.map, but that causes
+// hundreds of clang warnings.
+module ImportAsMember_Private {
+  export *
+
+  module A {
+    header "ImportAsMember_Private.h"
+  }
+}
+
 module ObjCIRExtras {
   header "ObjCIRExtras.h"
   export *

test/ClangImporter/import-as-member.swift

@@ -1,8 +1,13 @@
 // RUN: %empty-directory(%t.mcp)
-// RUN: not %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-objc-interop -typecheck -F %S/Inputs/frameworks -I %S/Inputs/custom-modules -module-cache-path %t.mcp %s 2>&1 | %FileCheck %S/Inputs/custom-modules/ImportAsMember.h
+
+// RUN: not %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-objc-interop -typecheck -F %S/Inputs/frameworks -I %S/Inputs/custom-modules -module-cache-path %t.mcp %s >%t.txt 2>&1
+// RUN: %FileCheck %S/Inputs/custom-modules/ImportAsMember.h <%t.txt
+// RUN: %FileCheck %S/Inputs/custom-modules/ImportAsMember_Private.h <%t.txt
+
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-objc-interop -typecheck -F %S/Inputs/frameworks -I %S/Inputs/custom-modules -module-cache-path %t.mcp %s -verify
 
 import ImportAsMember
+import ImportAsMember_Private
 import ImportAsMemberSubmodules
 
 let _: IAMSOuter.Inner?