[clang][modules][deps] Parse "FW_Private" module map even after loading "FW" PCM

When Clang loads a PCM that depends on another PCM describing framework module "FW", `ModuleMap` registers "FW" as known, without seeing the module map that defines it (or the adjacent "FW_Private" module map). Later, when looking at a header from "FW_Private", `ModuleMap` returns early due to having knowledge about "FW" and never associates that header with "FW_Private", leading to it being treated as textual. This behavior is caused by D150292, where the scanner stops calling `HeaderSearch::lookupModule()` eagerly for every loaded PCM.

This patch skips an early check when trying to figure out the framework module for a header, which ensures the "FW" and (most importantly) "FW_Private" module maps can be parsed even after loading "FW" from a PCM. Note that the `HeaderSearch::loadModuleMapFile()` function we not call unconditionally has caching behavior of its own, meaning it will avoid parsing module map file repeatedly.

Depends on D150320.

Reviewed By: benlangmuir

Differential Revision: https://reviews.llvm.org/D150478

1 files changed, 1 insertions, 4 deletions

diff --git a/clang/lib/Lex/HeaderSearch.cpp b/clang/lib/Lex/HeaderSearch.cpp
index 6fe655f..3200d3d 100644
--- a/clang/lib/Lex/HeaderSearch.cpp
+++ b/clang/lib/Lex/HeaderSearch.cpp
@@ -1783,9 +1783,6 @@ HeaderSearch::lookupModuleMapFile(DirectoryEntryRef Dir, bool IsFramework) {
 
 Module *HeaderSearch::loadFrameworkModule(StringRef Name, DirectoryEntryRef Dir,
                                           bool IsSystem) {
-  if (Module *Module = ModMap.findModule(Name))
-    return Module;
-
   // Try to load a module map file.
   switch (loadModuleMapFile(Dir, IsSystem, /*IsFramework*/true)) {
   case LMM_InvalidModuleMap:
@@ -1794,10 +1791,10 @@ Module *HeaderSearch::loadFrameworkModule(StringRef Name, DirectoryEntryRef Dir,
       ModMap.inferFrameworkModule(Dir, IsSystem, /*Parent=*/nullptr);
     break;
 
-  case LMM_AlreadyLoaded:
   case LMM_NoDirectory:
     return nullptr;
 
+  case LMM_AlreadyLoaded:
   case LMM_NewlyLoaded:
     break;
   }