Allow /showIncludes with /P

[erichkeane]

Summary

r213589 was checked in as a solution to
https://bugs.llvm.org/show_bug.cgi?id=20336.

However, it is possible to use /EP with /P
to suppress #line directives AND output to
a file. There is no reason in that case to
suppress /showIncludes.

This was reported here:
https://bugs.llvm.org/show_bug.cgi?id=34997

[thakis]

Thanks!

cfe/trunk/lib/Driver/ToolChains/Clang.cpp

if (Args.hasArg(options::OPT__SLASH_Zl)) {
     // This provides POSIX compatibility (maps 'open' to '_open'), which most
     // users want.  The /Za flag to cl.exe turns this off, but it's not
     // implemented in clang.
     CmdArgs.push_back("--dependent-lib=oldnames");
   }
 
   // Both /showIncludes and /E (and /EP) write to stdout. Allowing both
   // would produce interleaved output, so ignore /showIncludes in such cases.
-  if (!Args.hasArg(options::OPT_E) && !Args.hasArg(options::OPT__SLASH_EP))
+  if ((!Args.hasArg(options::OPT_E) && !Args.hasArg(options::OPT__SLASH_EP)) ||
+      (Args.hasArg(options::OPT__SLASH_P) &&
+       Args.hasArg(options::OPT__SLASH_EP) && !Args.hasArg(options::OPT_E)))
     if (Arg *A = Args.getLastArg(options::OPT_show_includes))
       A->render(Args, CmdArgs);
 
   // This controls whether or not we emit RTTI data for polymorphic types.
   if (Args.hasFlag(options::OPT__SLASH_GR_, options::OPT__SLASH_GR,
                    /*default=*/false))
     CmdArgs.push_back("-fno-rtti-data");
 

cfe/trunk/test/Driver/cl-options.c

 // RUN: %clang_cl /Qvec /Qvec- -### -- %s 2>&1 | FileCheck -check-prefix=Qvec_ %s
 // Qvec_-NOT: -vectorize-loops
 
 // RUN: %clang_cl /showIncludes -### -- %s 2>&1 | FileCheck -check-prefix=showIncludes %s
 // showIncludes: --show-includes
 
 // RUN: %clang_cl /E /showIncludes -### -- %s 2>&1 | FileCheck -check-prefix=showIncludes_E %s
 // RUN: %clang_cl /EP /showIncludes -### -- %s 2>&1 | FileCheck -check-prefix=showIncludes_E %s
+// RUN: %clang_cl /E /EP /showIncludes -### -- %s 2>&1 | FileCheck -check-prefix=showIncludes_E %s
 // showIncludes_E: warning: argument unused during compilation: '--show-includes'
 
+// RUN: %clang_cl /EP /P /showIncludes -### -- %s 2>&1 | FileCheck -check-prefix=showIncludes_E_And_P %s
+// showIncludes_E_And_P-NOT: warning: argument unused during compilation: '--show-includes'
+
 // /source-charset: should warn on everything except UTF-8.
 // RUN: %clang_cl /source-charset:utf-16 -### -- %s 2>&1 | FileCheck -check-prefix=source-charset-utf-16 %s
 // source-charset-utf-16: invalid value 'utf-16'
 
 // /execution-charset: should warn on everything except UTF-8.
 // RUN: %clang_cl /execution-charset:utf-16 -### -- %s 2>&1 | FileCheck -check-prefix=execution-charset-utf-16 %s
 // execution-charset-utf-16: invalid value 'utf-16'
 //