[clang-cl] Treat inputs as C++ with /E, like MSVC
midl invokes the compiler on .idl files with /E. Before this change, we
would treat unrecognized inputs as object files. Now we pre-process to
stdout as expected. I checked that MSVC defines __cplusplus when invoked
this way, so treating the input as C++ seems like the right thing to do.
After this change, I was able to run midl like this with clang-cl:
$ midl -cpp_cmd clang-cl.exe foo.idl
Things worked for the example IDL file in the Microsoft documentation,
but beyond that, I don't know if this will work well.
Fixes PR40140
llvm-svn: 350072
diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index dfc0faa..725bf27 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -2057,7 +2057,8 @@
Ty = types::TY_C;
} else {
// Otherwise lookup by extension.
- // Fallback is C if invoked as C preprocessor or Object otherwise.
+ // Fallback is C if invoked as C preprocessor, C++ if invoked with
+ // clang-cl /E, or Object otherwise.
// We use a host hook here because Darwin at least has its own
// idea of what .s is.
if (const char *Ext = strrchr(Value, '.'))
@@ -2066,6 +2067,8 @@
if (Ty == types::TY_INVALID) {
if (CCCIsCPP())
Ty = types::TY_C;
+ else if (IsCLMode() && Args.hasArgNoClaim(options::OPT_E))
+ Ty = types::TY_CXX;
else
Ty = types::TY_Object;
}