[clang][modules] Do consider module maps of included textual headers affecting

Author: jansvoboda11

clang/lib/Serialization/ASTWriter.cpp

@@ -187,8 +187,8 @@ GetAffectingModuleMaps(const Preprocessor &PP, Module *RootModule) {
       continue;
 
     const HeaderFileInfo *HFI = HS.getExistingLocalFileInfo(*File);
-    if (!HFI || ((HFI->isModuleHeader || HFI->isTextualModuleHeader) &&
-                 !HFI->isCompilingModuleHeader))
+    if (!HFI || (HFI->isModuleHeader && !HFI->isCompilingModuleHeader) ||
+        (HFI->isTextualModuleHeader && !PP.alreadyIncluded(*File)))
       continue;
 
     for (const auto &KH : HS.findResolvedModulesForHeader(*File)) {
@@ -2058,12 +2058,14 @@ void ASTWriter::WriteHeaderSearch(const HeaderSearch &HS) {
 
     // Get the file info. Skip emitting this file if we have no information on
     // it as a header file (in which case HFI will be null) or if it hasn't
-    // changed since it was loaded. Also skip it if it's for a non-excluded
-    // header from a different module; in that case, we rely on the module(s)
-    // containing the header to provide this information.
+    // changed since it was loaded. Also skip it if it's for a modular header
+    // from a different module; in that case, we rely on the module(s)
+    // containing the header to provide this information. Also skip it if it's
+    // for a textual header from a different module that has not been included;
+    // in that case, we don't need the information at all.
     const HeaderFileInfo *HFI = HS.getExistingLocalFileInfo(*File);
-    if (!HFI || ((HFI->isModuleHeader || HFI->isTextualModuleHeader) &&
-                 !HFI->isCompilingModuleHeader))
+    if (!HFI || (HFI->isModuleHeader && !HFI->isCompilingModuleHeader) ||
+        (HFI->isTextualModuleHeader && !PP->alreadyIncluded(*File)))
       continue;
 
     // Massage the file path into an appropriate form.

clang/test/Modules/prune-non-affecting-module-map-files-textual.c

@@ -1,26 +1,20 @@
 // This test checks that a module map with a textual header can be marked as
-// non-affecting.
+// non-affecting if its header did not get included.
 
 // RUN: rm -rf %t && mkdir %t
 // RUN: split-file %s %t
 
 //--- A.modulemap
 module A { textual header "A.h" }
 //--- B.modulemap
-module B { header "B.h" export * }
+module B { header "B.h" }
 //--- A.h
-typedef int A_int;
 //--- B.h
-#include "A.h"
-typedef A_int B_int;
-
-// RUN: %clang_cc1 -fmodules -emit-module %t/A.modulemap -fmodule-name=A -o %t/A.pcm \
-// RUN:   -fmodule-map-file=%t/A.modulemap -fmodule-map-file=%t/B.modulemap
 
 // RUN: %clang_cc1 -fmodules -emit-module %t/B.modulemap -fmodule-name=B -o %t/B0.pcm \
-// RUN:   -fmodule-map-file=%t/A.modulemap -fmodule-map-file=%t/B.modulemap -fmodule-file=%t/A.pcm
+// RUN:   -fmodule-map-file=%t/A.modulemap -fmodule-map-file=%t/B.modulemap
 
 // RUN: %clang_cc1 -fmodules -emit-module %t/B.modulemap -fmodule-name=B -o %t/B1.pcm \
-// RUN:                                    -fmodule-map-file=%t/B.modulemap -fmodule-file=%t/A.pcm
+// RUN:                                    -fmodule-map-file=%t/B.modulemap
 
 // RUN: diff %t/B0.pcm %t/B1.pcm