clang-cl: Don't warn about overriding /MD with /MT, /Fo with another /Fo, etc.

I put in the warnings because MSVC has them, but I don't think they're very
useful.

Clang does not warn about overriding flags in general, e.g. it's perfectly
fine to have -fomit-frame-pointer followed by -fno-omit-frame-pointer.

We should focus on warning where things get confusing, such as with the
/TP and /TC options. In "clang-cl /TC a.c /TP b.cc", the user might not
realize that the /TP flag will apply to both files, and we warn about that.

Differential Revision: http://llvm-reviews.chandlerc.com/D1718

llvm-svn: 190964

1 files changed, 0 insertions, 22 deletions

diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index 7ad09accd8c..a2cf06a20cd 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -284,26 +284,6 @@ DerivedArgList *Driver::TranslateInputArgs(const InputArgList &Args) const {
   return DAL;
 }
 
-/// \brief Check whether there are multiple instances of OptionID in Args, and
-/// if so, issue a diagnostics about it.
-static void DiagnoseOptionOverride(const Driver &D, const DerivedArgList &Args,
-                                   unsigned OptionID) {
-  assert(Args.hasArg(OptionID));
-
-  arg_iterator it = Args.filtered_begin(OptionID);
-  arg_iterator ie = Args.filtered_end();
-  Arg *Previous = *it;
-  ++it;
-
-  while (it != ie) {
-    D.Diag(clang::diag::warn_drv_overriding_joined_option)
-        << Previous->getSpelling() << Previous->getValue()
-        << (*it)->getSpelling() << (*it)->getValue();
-    Previous = *it;
-    ++it;
-  }
-}
-
 Compilation *Driver::BuildCompilation(ArrayRef<const char *> ArgList) {
   llvm::PrettyStackTraceString CrashInfo("Compilation construction");
 
@@ -1158,7 +1138,6 @@ void Driver::BuildActions(const ToolChain &TC, DerivedArgList &Args,
 
   // Diagnose misuse of /Fo.
   if (Arg *A = Args.getLastArg(options::OPT__SLASH_Fo)) {
-    DiagnoseOptionOverride(*this, Args, options::OPT__SLASH_Fo);
     StringRef V = A->getValue();
     if (V.empty()) {
       // It has to have a value.
@@ -1174,7 +1153,6 @@ void Driver::BuildActions(const ToolChain &TC, DerivedArgList &Args,
 
   // Diagnose misuse of /Fe.
   if (Arg *A = Args.getLastArg(options::OPT__SLASH_Fe)) {
-    DiagnoseOptionOverride(*this, Args, options::OPT__SLASH_Fe);
     if (A->getValue()[0] == '\0') {
       // It has to have a value.
       Diag(clang::diag::err_drv_missing_argument) << A->getSpelling() << 1;