[modules] Allow frameworks to have only a private module without a public one.

Support only preferred spelling 'Modules/module.private.modulemap' and
not the deprecated 'module_private.map'.

rdar://problem/57715533

Reviewed By: bruno

Differential Revision: https://reviews.llvm.org/D75311

1 files changed, 10 insertions, 0 deletions

diff --git a/clang/lib/Lex/HeaderSearch.cpp b/clang/lib/Lex/HeaderSearch.cpp
index 65d109e..1199f75 100644
--- a/clang/lib/Lex/HeaderSearch.cpp
+++ b/clang/lib/Lex/HeaderSearch.cpp
@@ -1568,6 +1568,16 @@ HeaderSearch::lookupModuleMapFile(const DirectoryEntry *Dir, bool IsFramework) {
   llvm::sys::path::append(ModuleMapFileName, "module.map");
   if (auto F = FileMgr.getFile(ModuleMapFileName))
     return *F;
+
+  // For frameworks, allow to have a private module map with a preferred
+  // spelling when a public module map is absent.
+  if (IsFramework) {
+    ModuleMapFileName = Dir->getName();
+    llvm::sys::path::append(ModuleMapFileName, "Modules",
+                            "module.private.modulemap");
+    if (auto F = FileMgr.getFile(ModuleMapFileName))
+      return *F;
+  }
   return nullptr;
 }