Add #pragma clang module begin/end pragmas and generate them when preprocessing a module.

These pragmas are intended to simulate the effect of entering or leaving a file
with an associated module. This is not completely implemented yet: declarations
between the pragmas will not be attributed to the correct module, but macro
visibility is already functional.

Modules named by #pragma clang module begin must already be known to clang (in
some module map that's either loaded or on the search path).

llvm-svn: 302098

3 files changed, 58 insertions, 3 deletions

diff --git a/clang/test/Modules/Inputs/preprocess/file2.h b/clang/test/Modules/Inputs/preprocess/file2.h
new file mode 100644
index 00000000000..04bf796d1e9
--- /dev/null
+++ b/clang/test/Modules/Inputs/preprocess/file2.h
@@ -0,0 +1,2 @@
+#include "file.h"
+extern int file2;
diff --git a/clang/test/Modules/Inputs/preprocess/module.modulemap b/clang/test/Modules/Inputs/preprocess/module.modulemap
index a5c5b61dddc..943435a953d 100644
--- a/clang/test/Modules/Inputs/preprocess/module.modulemap
+++ b/clang/test/Modules/Inputs/preprocess/module.modulemap
@@ -1,2 +1,2 @@
 module fwd { header "fwd.h" export * }
-module file { header "file.h" export * }
+module file { header "file.h" header "file2.h" export * }
diff --git a/clang/test/Modules/preprocess-module.cpp b/clang/test/Modules/preprocess-module.cpp
index 99fe8cf8c30..337cafbf65b 100644
--- a/clang/test/Modules/preprocess-module.cpp
+++ b/clang/test/Modules/preprocess-module.cpp
@@ -3,10 +3,63 @@
 // RUN: not %clang_cc1 -fmodules -fmodule-name=file -I%S/Inputs/preprocess -x c++-module-map %S/Inputs/preprocess/module.modulemap -E 2>&1 | FileCheck %s --check-prefix=MISSING-FWD
 // MISSING-FWD: module 'fwd' is needed
 
-// RUN: %clang_cc1 -fmodules -fmodule-name=file -fmodules-cache-path=%t -I%S/Inputs/preprocess -x c++-module-map %S/Inputs/preprocess/module.modulemap -E | FileCheck %s
+// RUN: %clang_cc1 -fmodules -fmodule-name=file -fmodules-cache-path=%t -I%S/Inputs/preprocess -x c++-module-map %S/Inputs/preprocess/module.modulemap -E | FileCheck %s --check-prefix=CHECK --check-prefix=NO-REWRITE
+// RUN: %clang_cc1 -fmodules -fmodule-name=file -fmodules-cache-path=%t -I%S/Inputs/preprocess -x c++-module-map %S/Inputs/preprocess/module.modulemap -E -frewrite-includes | FileCheck %s --check-prefix=CHECK --check-prefix=REWRITE
+
+// == file.h
 // CHECK: # 1 "<module-includes>"
+// REWRITE: #if 0
+// REWRITE: #include "file.h"
+// REWRITE: #endif
+//
+// FIXME: It would be preferable to consistently put the module begin/end in
+// the same file, but the relative ordering of PP callbacks and module
+// begin/end tokens makes that difficult.
+//
+// REWRITE: #pragma clang module begin file
 // CHECK: # 1 "{{.*}}file.h" 1
+// NO-REWRITE: #pragma clang module begin file
+// NO-REWRITE: # 1 "{{.*}}file.h"{{$}}
+//
 // CHECK: struct __FILE;
-// CHECK: #pragma clang module import fwd /* clang -E: implicit import for #include "fwd.h" */
+// CHECK: #pragma clang module import fwd /* clang {{-E|-frewrite-includes}}: implicit import
 // CHECK: typedef struct __FILE FILE;
+//
+// REWRITE: #pragma clang module end
 // CHECK: # 2 "<module-includes>" 2
+// NO-REWRITE: #pragma clang module end
+
+// == file2.h
+// REWRITE: #if 0
+// REWRITE: #include "file2.h"
+// REWRITE: #endif
+//
+// REWRITE: #pragma clang module begin file
+// CHECK: # 1 "{{.*}}file2.h" 1
+// NO-REWRITE: #pragma clang module begin file
+//
+// ==== recursively re-enter file.h
+// REWRITE: #if 0
+// REWRITE: #include "file.h"
+// REWRITE: #endif
+//
+// REWRITE: #pragma clang module begin file
+// CHECK: # 1 "{{.*}}file.h" 1
+// NO-REWRITE: #pragma clang module begin file
+// NO-REWRITE: # 1 "{{.*}}file.h"{{$}}
+//
+// CHECK: struct __FILE;
+// CHECK: #pragma clang module import fwd /* clang {{-E|-frewrite-includes}}: implicit import
+// CHECK: typedef struct __FILE FILE;
+//
+// REWRITE: #pragma clang module end
+// CHECK: # 2 "{{.*}}file2.h" 2
+// NO-REWRITE: #pragma clang module end
+// NO-REWRITE: # 2 "{{.*}}file2.h"{{$}}
+// ==== return to file2.h
+//
+// CHECK: extern int file2;
+//
+// REWRITE: #pragma clang module end
+// CHECK: # 3 "<module-includes>" 2
+// NO-REWRITE: #pragma clang module end