Driver: Handle properly calling dsymutil when source input is
preceeded by a linker input flag.
 - <rdar://problem/6757236> clang should make a dSYM when going
   straight from source to binary

 - This still matches gcc, but the right way to solve this would be to
   detect the situation we care about (we are compiling from source
   and linking in one step), instead of looking at the suffix of the
   input file. The Tool doesn't quite have enough information to do
   this yet, however.

 - Also, find the suffix correctly.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@68417 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index 70daaf5..bbf7c9e 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -1446,13 +1446,23 @@
     Args.MakeArgString(getToolChain().GetProgramPath(C, "collect2").c_str());
   Dest.addCommand(new Command(Exec, CmdArgs));  
 
+  // Find the first non-empty base input (we want to ignore linker
+  // inputs).
+  const char *BaseInput = "";
+  for (unsigned i = 0, e = Inputs.size(); i != e; ++i) {
+    if (Inputs[i].getBaseInput()[0] != '\0') {
+      BaseInput = Inputs[i].getBaseInput();
+      break;
+    }
+  }
+  
   if (Args.getLastArg(options::OPT_g_Group) &&
       !Args.getLastArg(options::OPT_gstabs) &&
       !Args.getLastArg(options::OPT_g0)) {
     // FIXME: This is gross, but matches gcc. The test only considers
     // the suffix (not the -x type), and then only of the first
-    // input. Awesome.
-    const char *Suffix = strchr(Inputs[0].getBaseInput(), '.');
+    // source input. Awesome.
+    const char *Suffix = strrchr(BaseInput, '.');
     if (Suffix && isSourceSuffix(Suffix + 1)) {
       const char *Exec = 
        Args.MakeArgString(getToolChain().GetProgramPath(C, "dsymutil").c_str());