Treat module headers wrapped by our builtin headers as implicitly being textual

headers. We previously got this check backwards and treated the wrapper header
as being textual.

This is important because our wrapper headers sometimes inject macros into the
system headers that they #include_next, and sometimes replace them entirely.

llvm-svn: 285152

clang/lib/Lex/ModuleMap.cpp

@@ -1881,16 +1881,20 @@ void ModuleMapParser::parseHeaderDecl(MMToken::TokenKind LeadingToken,
       Module::Header H = {RelativePathName.str(), File};
       Map.excludeHeader(ActiveModule, H);
     } else {
-      // If there is a builtin counterpart to this file, add it now as a textual
-      // header, so it can be #include_next'd by the wrapper header, and can
-      // receive macros from the wrapper header.
+      // If there is a builtin counterpart to this file, add it now so it can
+      // wrap the system header.
       if (BuiltinFile) {
         // FIXME: Taking the name from the FileEntry is unstable and can give
         // different results depending on how we've previously named that file
         // in this build.
         Module::Header H = { BuiltinFile->getName(), BuiltinFile };
-        Map.addHeader(ActiveModule, H, ModuleMap::ModuleHeaderRole(
-                                           Role | ModuleMap::TextualHeader));
+        Map.addHeader(ActiveModule, H, Role);
+
+        // If we have both a builtin and system version of the file, the
+        // builtin version may want to inject macros into the system header, so
+        // force the system header to be treated as a textual header in this
+        // case.
+        Role = ModuleMap::ModuleHeaderRole(Role | ModuleMap::TextualHeader);
       }
 
       // Record this header.

clang/test/Modules/Inputs/System/usr/include/stdbool.h

@@ -1 +1 @@
-#include_next <stdbool.h>
+// Testing hack: does not define bool/true/false.

clang/test/Modules/Inputs/libc-libcxx/sysroot/usr/include/stddef.h

@@ -1,2 +1 @@
 // stddef.h
-#include_next "stddef.h"

clang/test/Modules/cstd.m

@@ -1,5 +1,5 @@
 // RUN: rm -rf %t
-// RUN: %clang_cc1 -fsyntax-only -isystem %S/Inputs/System/usr/include -ffreestanding -fmodules -fimplicit-module-maps -fmodules-cache-path=%t -D__need_wint_t -Werror=implicit-function-declaration %s
+// RUN: %clang_cc1 -fsyntax-only -internal-isystem %S/Inputs/System/usr/include -fmodules -fimplicit-module-maps -fmodules-cache-path=%t -D__need_wint_t -Werror=implicit-function-declaration %s
 
 @import uses_other_constants;
 const double other_value = DBL_MAX;