clang-cl: Don't treat linker input files differently when /TP or /TC is specified.

Summary: This fixes http://llvm.org/PR20923.

Test Plan: This patch includes an automated test.

Reviewers: hansw

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D5334

llvm-svn: 217699
diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index 04d4d44..e448eb1 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -1076,8 +1076,17 @@
         }
       } else {
         assert(InputTypeArg && "InputType set w/o InputTypeArg");
-        InputTypeArg->claim();
-        Ty = InputType;
+        if (!InputTypeArg->getOption().matches(options::OPT_x)) {
+          // If emulating cl.exe, make sure that /TC and /TP don't affect input
+          // object files.
+          const char *Ext = strrchr(Value, '.');
+          if (Ext && TC.LookupTypeForExtension(Ext + 1) == types::TY_Object)
+            Ty = types::TY_Object;
+        }
+        if (Ty == types::TY_INVALID) {
+          Ty = InputType;
+          InputTypeArg->claim();
+        }
       }
 
       if (DiagnoseInputExistence(*this, Args, Value))
diff --git a/clang/test/Driver/cl-inputs.c b/clang/test/Driver/cl-inputs.c
index 029aead..c0d4778 100644
--- a/clang/test/Driver/cl-inputs.c
+++ b/clang/test/Driver/cl-inputs.c
@@ -34,6 +34,14 @@
 // WARN: note: The last /TC or /TP option takes precedence over earlier instances
 // WARN-NOT: note
 
+// RUN: env LIB=%S/Inputs/cl-libs %clang_cl /c /TP cl-test.lib %s -### 2>&1 | FileCheck -check-prefix=TPlib %s
+// TPlib: warning: cl-test.lib: 'linker' input unused
+// TPlib-NOT: cl-test.lib
+
+// RUN: env LIB=%S/Inputs/cl-libs %clang_cl /c /TC cl-test.lib %s -### 2>&1 | FileCheck -check-prefix=TClib %s
+// TClib: warning: cl-test.lib: 'linker' input unused
+// TClib-NOT: cl-test.lib
+
 // RUN: not %clang_cl - 2>&1 | FileCheck -check-prefix=STDIN %s
 // STDIN: error: use /Tc or /Tp