[Preprocessor] Iterating over all macros should include those from modules.

So, iterate over the list of macros mentioned in modules, and make sure those
are in the master table.

This isn't particularly efficient, but hopefully it's something that isn't
done too often.

PR23929 and rdar://problem/21480635

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@240571 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Lex/Preprocessor.cpp

@@ -286,6 +286,10 @@ Preprocessor::macro_begin(bool IncludeExternalMacros) const {
     ExternalSource->ReadDefinedMacros();
   }
 
+  // Make sure we cover all macros in visible modules.
+  for (const ModuleMacro &Macro : ModuleMacros)
+    CurSubmoduleState->Macros.insert(std::make_pair(Macro.II, MacroState()));
+
   return CurSubmoduleState->Macros.begin();
 }
 

test/CodeCompletion/macros-in-modules.c

+// RUN: rm -rf %t && mkdir %t
+// RUN: echo 'module Foo { header "foo.h" }' > %t/module.modulemap
+// RUN: echo '#define FOO_MACRO 42' > %t/foo.h
+// RUN: c-index-test -code-completion-at=%s:9:1 -I %t %s | FileCheck %s
+// RUN: c-index-test -code-completion-at=%s:9:1 -I %t -fmodules %s | FileCheck %s
+
+#include "foo.h"
+int x =
+/*here*/1;
+
+// CHECK: FOO_MACRO

test/CodeCompletion/macros-in-modules.m

+// RUN: rm -rf %t && mkdir %t
+// RUN: echo 'module Foo { header "foo.h" }' > %t/module.modulemap
+// RUN: echo '#define FOO_MACRO 42' > %t/foo.h
+// RUN: c-index-test -code-completion-at=%s:8:1 -I %t -fmodules %s | FileCheck %s
+
+@import Foo;
+int x =
+/*here*/1;
+
+// CHECK: FOO_MACRO