[Driver] Use -fuse-line-directives by default in MSVC mode

mstorsjo · mstorsjo · commit c33639227e05 · 2018-05-07T20:26:09.000Z
Don't use the GNU extension form of line markers in MSVC mode. Differential Revision: https://reviews.llvm.org/D46520 llvm-svn: 331666
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -4215,9 +4215,9 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
                    IsWindowsMSVC))
     CmdArgs.push_back("-fms-extensions");
 
-  // -fno-use-line-directives is default.
+  // -fno-use-line-directives is default, except for MSVC targets.
   if (Args.hasFlag(options::OPT_fuse_line_directives,
-                   options::OPT_fno_use_line_directives, false))
+                   options::OPT_fno_use_line_directives, IsWindowsMSVC))
     CmdArgs.push_back("-fuse-line-directives");
 
   // -fms-compatibility=0 is default.
diff --git a/clang/test/Driver/cl-options.c b/clang/test/Driver/cl-options.c
@@ -28,6 +28,7 @@
 
 // RUN: %clang_cl /E -### -- %s 2>&1 | FileCheck -check-prefix=E %s
 // E: "-E"
+// E: "-fuse-line-directives"
 // E: "-o" "-"
 
 // RUN: %clang_cl /EP -### -- %s 2>&1 | FileCheck -check-prefix=EP %s
