[clang][modules] Preserve the module map that allowed inferring (#113389)

With inferred modules, the dependency scanner takes care to replace the
fake "__inferred_module.map" path with the file that allowed the module
to be inferred. However, this only worked when such a module was
imported directly in the TU. Whenever such module got loaded
transitively, the scanner would fail to perform the replacement. This is
caused by the fact that PCM files are lossy and drop this information.

This patch makes sure that PCMs include this file for each submodule (in
the `SUBMODULE_DEFINITION` record), fixes one existing test with an
incorrect assertion, and does a little drive-by refactoring of
`ModuleMap`.

1 files changed, 4 insertions, 7 deletions

diff --git a/clang/lib/Lex/ModuleMap.cpp b/clang/lib/Lex/ModuleMap.cpp
index bc76a54..201ab91 100644
--- a/clang/lib/Lex/ModuleMap.cpp
+++ b/clang/lib/Lex/ModuleMap.cpp
@@ -657,8 +657,7 @@ ModuleMap::findOrCreateModuleForHeaderInUmbrellaDir(FileEntryRef File) {
             llvm::sys::path::stem(SkippedDir.getName()), NameBuf);
         Result = findOrCreateModule(Name, Result, /*IsFramework=*/false,
                                     Explicit).first;
-        InferredModuleAllowedBy[Result] = UmbrellaModuleMap;
-        Result->IsInferred = true;
+        setInferredModuleAllowedBy(Result, UmbrellaModuleMap);
 
         // Associate the module and the directory.
         UmbrellaDirs[SkippedDir] = Result;
@@ -675,8 +674,7 @@ ModuleMap::findOrCreateModuleForHeaderInUmbrellaDir(FileEntryRef File) {
                          llvm::sys::path::stem(File.getName()), NameBuf);
       Result = findOrCreateModule(Name, Result, /*IsFramework=*/false,
                                   Explicit).first;
-      InferredModuleAllowedBy[Result] = UmbrellaModuleMap;
-      Result->IsInferred = true;
+      setInferredModuleAllowedBy(Result, UmbrellaModuleMap);
       Result->addTopHeader(File);
 
       // If inferred submodules export everything they import, add a
@@ -1097,8 +1095,7 @@ Module *ModuleMap::inferFrameworkModule(DirectoryEntryRef FrameworkDir,
   Module *Result = new (ModulesAlloc.Allocate())
       Module(ModuleConstructorTag{}, ModuleName, SourceLocation(), Parent,
              /*IsFramework=*/true, /*IsExplicit=*/false, NumCreatedModules++);
-  InferredModuleAllowedBy[Result] = ModuleMapFID;
-  Result->IsInferred = true;
+  setInferredModuleAllowedBy(Result, ModuleMapFID);
   if (!Parent) {
     if (LangOpts.CurrentModule == ModuleName)
       SourceModule = Result;
@@ -1346,7 +1343,7 @@ ModuleMap::getModuleMapFileForUniquing(const Module *M) const {
 }
 
 void ModuleMap::setInferredModuleAllowedBy(Module *M, FileID ModMapFID) {
-  assert(M->IsInferred && "module not inferred");
+  M->IsInferred = true;
   InferredModuleAllowedBy[M] = ModMapFID;
 }