[Preprocessor] Support for '-dI' flag

Re-introduce r285411.

Implement the -dI as supported by GCC: Output ‘#include’ directives in addition
to the result of preprocessing.

This change aims to add this option, pass it through to the preprocessor via
the options class, and when inclusions occur we output some information (+ test
cases).

Patch by Steve O'Brien!

Differential Revision: https://reviews.llvm.org/D26089

llvm-svn: 287275

4 files changed, 20 insertions, 0 deletions

diff --git a/clang/test/Preprocessor/dump_import.h b/clang/test/Preprocessor/dump_import.h
new file mode 100644
index 00000000000..fded1e52cbb
--- /dev/null
+++ b/clang/test/Preprocessor/dump_import.h
@@ -0,0 +1 @@
+#define DUMP_IMPORT_TESTVAL 1
diff --git a/clang/test/Preprocessor/dump_import.m b/clang/test/Preprocessor/dump_import.m
new file mode 100644
index 00000000000..20424ad507b
--- /dev/null
+++ b/clang/test/Preprocessor/dump_import.m
@@ -0,0 +1,6 @@
+// RUN: %clang_cc1 -E -dI %s -o - | FileCheck %s
+// CHECK: {{^}}#import "dump_
+
+// See also `dump_include.c` which tests other inclusion cases with `-dI`.
+
+#import "dump_import.h"
diff --git a/clang/test/Preprocessor/dump_include.c b/clang/test/Preprocessor/dump_include.c
new file mode 100644
index 00000000000..4d7d857d5f1
--- /dev/null
+++ b/clang/test/Preprocessor/dump_include.c
@@ -0,0 +1,11 @@
+// RUN: %clang_cc1 -w -E -dI -isystem %S -imacros %S/dump_include.h %s -o - | FileCheck %s
+// CHECK: {{^}}#__include_macros "{{.*}}dump_
+// CHECK: {{^}}#include <dump_
+// CHECK: {{^}}#include "dump_
+// CHECK: {{^}}#include_next "dump_
+
+// See also `dump_import.m` which tests the `#import` directive with `-dI`.
+
+#include <dump_include.h>
+#include "dump_include.h"
+#include_next "dump_include.h"
diff --git a/clang/test/Preprocessor/dump_include.h b/clang/test/Preprocessor/dump_include.h
new file mode 100644
index 00000000000..9dafaa50b5c
--- /dev/null
+++ b/clang/test/Preprocessor/dump_include.h
@@ -0,0 +1,2 @@
+#pragma once
+#define DUMP_INCLUDE_TESTVAL 1