Merge pull request swiftlang#9722 from benlangmuir/fix-nullptr-deref-6.1

[6.1] [cas] Definitions from unimported submodules should not be visible

Author: nkcsgexi

clang/lib/Serialization/ASTReaderDecl.cpp

@@ -3192,7 +3192,7 @@ bool ASTReader::isConsumerInterestedIn(Decl *D) {
   // emitted when we import the relevant module.
   if (isPartOfPerModuleInitializer(D)) {
     auto *M = D->getImportedOwningModule();
-    if (M && M->Kind == Module::ModuleMapModule &&
+    if (M && M->isModuleMapModule() &&
         getContext().DeclMustBeEmitted(D))
       return false;
   }

clang/test/CAS/modules-include-tree-unimported-impl.c

@@ -0,0 +1,50 @@
+// Check that a definition for a symbol in an unimported submodule is not
+// visible for codegen.
+
+// REQUIRES: ondisk_cas
+
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+// RUN: sed "s|DIR|%/t|g" %t/cdb.json.template > %t/cdb.json
+
+// RUN: clang-scan-deps -compilation-database %t/cdb.json -j 1 \
+// RUN:   -cas-path %t/cas -module-files-dir %t/outputs \
+// RUN:   -format experimental-include-tree-full -mode preprocess-dependency-directives \
+// RUN:   > %t/deps.json
+
+// RUN: %deps-to-rsp %t/deps.json --module Mod > %t/Mod.rsp
+// RUN: %deps-to-rsp %t/deps.json --tu-index 0 > %t/tu.rsp
+// RUN: %clang @%t/Mod.rsp
+// RUN: %clang @%t/tu.rsp -o - | FileCheck %s
+
+// CHECK-NOT: @record = global
+// CHECK: @record = external global
+
+//--- cdb.json.template
+[{
+  "file": "DIR/tu.c",
+  "directory": "DIR",
+  "command": "clang -S -emit-llvm DIR/tu.c -fmodules -fimplicit-modules -fimplicit-module-maps -fmodules-cache-path=DIR/module-cache"
+}]
+
+//--- module.modulemap
+module Mod {
+  module A {
+    header "A.h"
+  }
+  explicit module B {
+    header "B.h"
+  }
+}
+
+//--- A.h
+extern int record;
+
+//--- B.h
+int record = 7;
+
+//--- tu.c
+#include "A.h"
+int tu(void) {
+  return record;
+}