Revert "[modules] Fix 37878; Autoload subdirectory modulemaps with specific LangOpts"

This reverts commit f40124d4f05ecf4f880cf4e8f26922d861f705f3 / r336660.

This change shouldn't be affecting `@import` behavior, but turns out it is:
https://ci.swift.org/view/swift-master-next/job/oss-swift-incremental-RA-osx-master-next/2800/consoleFull#-12570166563122a513-f36a-4c87-8ed7-cbc36a1ec144

Working on a reduced testcase for this, reverting in the meantime.

rdar://problem/42102222

llvm-svn: 336920
diff --git a/clang/lib/Lex/HeaderSearch.cpp b/clang/lib/Lex/HeaderSearch.cpp
index b1a2ef1..312bd2d 100644
--- a/clang/lib/Lex/HeaderSearch.cpp
+++ b/clang/lib/Lex/HeaderSearch.cpp
@@ -198,15 +198,14 @@
   return Result.str().str();
 }
 
-Module *HeaderSearch::lookupModule(StringRef ModuleName, bool AllowSearch,
-                                   bool AllowExtraModuleMapSearch) {
+Module *HeaderSearch::lookupModule(StringRef ModuleName, bool AllowSearch) {
   // Look in the module map to determine if there is a module by this name.
   Module *Module = ModMap.findModule(ModuleName);
   if (Module || !AllowSearch || !HSOpts->ImplicitModuleMaps)
     return Module;
 
   StringRef SearchName = ModuleName;
-  Module = lookupModule(ModuleName, SearchName, AllowExtraModuleMapSearch);
+  Module = lookupModule(ModuleName, SearchName);
 
   // The facility for "private modules" -- adjacent, optional module maps named
   // module.private.modulemap that are supposed to define private submodules --
@@ -217,14 +216,13 @@
   // could force building unwanted dependencies into the parent module and cause
   // dependency cycles.
   if (!Module && SearchName.consume_back("_Private"))
-    Module = lookupModule(ModuleName, SearchName, AllowExtraModuleMapSearch);
+    Module = lookupModule(ModuleName, SearchName);
   if (!Module && SearchName.consume_back("Private"))
-    Module = lookupModule(ModuleName, SearchName, AllowExtraModuleMapSearch);
+    Module = lookupModule(ModuleName, SearchName);
   return Module;
 }
 
-Module *HeaderSearch::lookupModule(StringRef ModuleName, StringRef SearchName,
-                                   bool AllowExtraModuleMapSearch) {
+Module *HeaderSearch::lookupModule(StringRef ModuleName, StringRef SearchName) {
   Module *Module = nullptr;
 
   // Look through the various header search paths to load any available module
@@ -283,9 +281,8 @@
       continue;
 
     // Load all module maps in the immediate subdirectories of this search
-    // directory if ModuleName was from @import.
-    if (AllowExtraModuleMapSearch)
-      loadSubdirectoryModuleMaps(SearchDirs[Idx]);
+    // directory.
+    loadSubdirectoryModuleMaps(SearchDirs[Idx]);
 
     // Look again for the module.
     Module = ModMap.findModule(ModuleName);