[clang][HeaderSearch] Fix implicit module when using header maps

Previously, if a header was found via in a header map, and not just remapped.
we wouldn't also find the module it maps to when using implicit modules (for
module maps that were explicitly loaded).

This diff just updates these code paths to also locate the owning module via
`findUsableModuleForHeader`.

Reviewed By: benlangmuir

Differential Revision: https://reviews.llvm.org/D103930

1 files changed, 9 insertions, 3 deletions

diff --git a/clang/lib/Lex/HeaderSearch.cpp b/clang/lib/Lex/HeaderSearch.cpp
index a650bbe..d09d3ae 100644
--- a/clang/lib/Lex/HeaderSearch.cpp
+++ b/clang/lib/Lex/HeaderSearch.cpp
@@ -491,7 +491,8 @@ OptionalFileEntryRef DirectoryLookup::LookupFile(
 
   IsInHeaderMap = true;
 
-  auto FixupSearchPath = [&]() {
+  auto FixupSearchPathAndFindUsableModule =
+      [&](auto File) -> OptionalFileEntryRef {
     if (SearchPath) {
       StringRef SearchPathRef(getName());
       SearchPath->clear();
@@ -501,6 +502,12 @@ OptionalFileEntryRef DirectoryLookup::LookupFile(
       RelativePath->clear();
       RelativePath->append(Filename.begin(), Filename.end());
     }
+    if (!HS.findUsableModuleForHeader(
+            &File.getFileEntry(), File.getFileEntry().getDir(),
+            RequestingModule, SuggestedModule, isSystemHeaderDirectory())) {
+      return std::nullopt;
+    }
+    return File;
   };
 
   // Check if the headermap maps the filename to a framework include
@@ -513,8 +520,7 @@ OptionalFileEntryRef DirectoryLookup::LookupFile(
   }
 
   if (auto Res = HS.getFileMgr().getOptionalFileRef(Dest, OpenFile)) {
-    FixupSearchPath();
-    return *Res;
+    return FixupSearchPathAndFindUsableModule(*Res);
   }
 
   // Header maps need to be marked as used whenever the filename matches.