[clang] NFCI: Split HeaderSearch::findAllModulesForHeader()

This mimics the `ModuleMap` API and enables D151854, where the `AllowCreation = true` function needs `FileEntryRef` but `AllowCreation = false` functions is happy with plain `FileEntry`. No functional change intended.

Reviewed By: benlangmuir

Differential Revision: https://reviews.llvm.org/D151853

clang/include/clang/Lex/HeaderSearch.h

@@ -670,8 +670,12 @@ class HeaderSearch {
   ///
   /// \ref findModuleForHeader should typically be used instead of this.
   ArrayRef<ModuleMap::KnownHeader>
-  findAllModulesForHeader(const FileEntry *File,
-                          bool AllowCreation = true) const;
+  findAllModulesForHeader(const FileEntry *File) const;
+
+  /// Like \ref findAllModulesForHeader, but do not attempt to infer module
+  /// ownership from umbrella headers if we've not already done so.
+  ArrayRef<ModuleMap::KnownHeader>
+  findResolvedModulesForHeader(const FileEntry *File) const;
 
   /// Read the contents of the given module map file.
   ///

clang/include/clang/Lex/ModuleMap.h

@@ -446,13 +446,9 @@ class ModuleMap {
   /// and does not consult the external source. (Those checks are the
   /// responsibility of \ref HeaderSearch.)
   ///
-  /// \param AllowCreation Whether to allow inference of a new submodule, or to
-  ///        only return existing known modules.
-  ///
   /// Typically, \ref findModuleForHeader should be used instead, as it picks
   /// the preferred module for the header.
-  ArrayRef<KnownHeader> findAllModulesForHeader(const FileEntry *File,
-                                                bool AllowCreation = true);
+  ArrayRef<KnownHeader> findAllModulesForHeader(const FileEntry *File);
 
   /// Like \ref findAllModulesForHeader, but do not attempt to infer module
   /// ownership from umbrella headers if we've not already done so.

clang/lib/Lex/HeaderSearch.cpp

@@ -1570,14 +1570,23 @@ HeaderSearch::findModuleForHeader(const FileEntry *File, bool AllowTextual,
 }
 
 ArrayRef<ModuleMap::KnownHeader>
-HeaderSearch::findAllModulesForHeader(const FileEntry *File,
-                                      bool AllowCreation) const {
+HeaderSearch::findAllModulesForHeader(const FileEntry *File) const {
   if (ExternalSource) {
     // Make sure the external source has handled header info about this file,
     // which includes whether the file is part of a module.
     (void)getExistingFileInfo(File);
   }
-  return ModMap.findAllModulesForHeader(File, AllowCreation);
+  return ModMap.findAllModulesForHeader(File);
+}
+
+ArrayRef<ModuleMap::KnownHeader>
+HeaderSearch::findResolvedModulesForHeader(const FileEntry *File) const {
+  if (ExternalSource) {
+    // Make sure the external source has handled header info about this file,
+    // which includes whether the file is part of a module.
+    (void)getExistingFileInfo(File);
+  }
+  return ModMap.findResolvedModulesForHeader(File);
 }
 
 static bool suggestModule(HeaderSearch &HS, const FileEntry *File,

clang/lib/Lex/ModuleMap.cpp

@@ -684,12 +684,12 @@ ModuleMap::findOrCreateModuleForHeaderInUmbrellaDir(const FileEntry *File) {
 }
 
 ArrayRef<ModuleMap::KnownHeader>
-ModuleMap::findAllModulesForHeader(const FileEntry *File, bool AllowCreation) {
+ModuleMap::findAllModulesForHeader(const FileEntry *File) {
   HeadersMap::iterator Known = findKnownHeader(File);
   if (Known != Headers.end())
     return Known->second;
 
-  if (AllowCreation && findOrCreateModuleForHeaderInUmbrellaDir(File))
+  if (findOrCreateModuleForHeaderInUmbrellaDir(File))
     return Headers.find(File)->second;
 
   return std::nullopt;

clang/lib/Serialization/ASTWriter.cpp

@@ -185,8 +185,7 @@ std::set<const FileEntry *> GetAffectingModuleMaps(const Preprocessor &PP,
     if (!HFI || (HFI->isModuleHeader && !HFI->isCompilingModuleHeader))
       continue;
 
-    for (const auto &KH :
-         HS.findAllModulesForHeader(File, /*AllowCreation=*/false)) {
+    for (const auto &KH : HS.findResolvedModulesForHeader(File)) {
       if (!KH.getModule())
         continue;
       ModulesToProcess.push_back(KH.getModule());