[modules] Allow the error when explicitly loading an incompatible module file

via -fmodule-file= to be turned off; in that case, just include the relevant
files textually. This allows module files to be unconditionally passed to all
compile actions via CXXFLAGS, and to be ignored for rules that specify custom
incompatible flags.

llvm-svn: 250577

1 files changed, 14 insertions, 5 deletions

diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index 740524c..8220a6e 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -1335,15 +1335,24 @@ bool CompilerInstance::loadModuleFile(StringRef FileName) {
                                                    std::move(Listener));
 
   // Try to load the module file.
-  if (ModuleManager->ReadAST(FileName, serialization::MK_ExplicitModule,
-                             SourceLocation(), ASTReader::ARR_None)
-          != ASTReader::Success)
-    return false;
-
+  switch (ModuleManager->ReadAST(FileName, serialization::MK_ExplicitModule,
+                                 SourceLocation(),
+                                 ASTReader::ARR_ConfigurationMismatch)) {
+  case ASTReader::Success:
   // We successfully loaded the module file; remember the set of provided
   // modules so that we don't try to load implicit modules for them.
   ListenerRef.registerAll();
   return true;
+
+  case ASTReader::ConfigurationMismatch:
+    // Ignore unusable module files.
+    getDiagnostics().Report(SourceLocation(), diag::warn_module_config_mismatch)
+        << FileName;
+    return true;
+
+  default:
+    return false;
+  }
 }
 
 ModuleLoadResult