Fix depfile name construction

- When using -o, the provided filename is using for constructing the depfile
  name (when -MMD is passed).
- The logic looks for the rightmost '.' character and replaces what comes after
  with 'd'.
- This works incorrectly when the filename has no extension and the directories
  have '.' in them (e.g. out.dir/test)
- This replaces the funciton to just llvm::sys::path functionality

Differential Revision: https://reviews.llvm.org/D67542

llvm-svn: 371853

clang/lib/Driver/ToolChains/Clang.cpp

@@ -6066,15 +6066,14 @@ const char *Clang::getBaseInputStem(const ArgList &Args,
 const char *Clang::getDependencyFileName(const ArgList &Args,
                                          const InputInfoList &Inputs) {
   // FIXME: Think about this more.
-  std::string Res;
 
   if (Arg *OutputOpt = Args.getLastArg(options::OPT_o)) {
-    std::string Str(OutputOpt->getValue());
-    Res = Str.substr(0, Str.rfind('.'));
-  } else {
-    Res = getBaseInputStem(Args, Inputs);
+    SmallString<128> OutputFilename(OutputOpt->getValue());
+    llvm::sys::path::replace_extension(OutputFilename, llvm::Twine('d'));
+    return Args.MakeArgString(OutputFilename);
   }
-  return Args.MakeArgString(Res + ".d");
+
+  return Args.MakeArgString(std::string(getBaseInputStem(Args, Inputs)) + ".d");
 }
 
 // Begin ClangAs

clang/test/Driver/metadata-with-dots.c

@@ -0,0 +1,11 @@
+// REQUIRES: shell
+// RUN: mkdir -p out.dir
+// RUN: cat %s > out.dir/test.c
+// RUN: %clang -E -MMD %s -o out.dir/test
+// RUN: test ! -f %out.d
+// RUN: test -f out.dir/test.d
+// RUN: rm -rf out.dir/test.d out.dir/ out.d
+int main (void)
+{
+    return 0;
+}