Use the newly added FindInEnvPath helper in clang

[hans]

lib/Driver/Driver.cpp

933

I think Optional<> provides a bool conversion operator, so you can just do: "return llvm::sys::FindInEnvPath("LIB", Value);".. and since the function is now just one line, maybe inline it into the caller.

lib/Driver/Tools.cpp

7556

This doesn't work. The previous code handles the case where there are multiple cl.exe on the PATH, whereas the new code just returns the first one.

This function is used in the Visual Studio clang-cl integration, where we rename clang-cl.exe to cl.exe and put it first on PATH. This function is then used to find the real cl.exe.

I think we have to leave this code as it is (though we can remove the definition of PathSeparators and use llvm::sys::EnvPathSeparator).

[• ehsan]

Good points. I'll submit a new patch once we decide where to put the function itself.

[• ehsan]

Addressed the review comment.

[hans]

lgtm

[• ehsan]

Landed in r212058.

lib/Driver/Driver.cpp

if (A && !A->getOption().matches(options::OPT_g0) &&
         Actions.pop_back();
         Actions.push_back(new VerifyDebugInfoJobAction(VerifyInput,
                                                        types::TY_Nothing));
       }
     }
   }
 }
 
-/// \brief Check whether the file referenced by Value exists in the LIB
-/// environment variable.
-static bool ExistsInLibDir(StringRef Value) {
-  llvm::Optional<std::string> OptPath = llvm::sys::Process::GetEnv("LIB");
-  if (!OptPath.hasValue())
-    return false;
-
-#ifdef LLVM_ON_WIN32
-  const StringRef PathSeparators = ";";
-#else
-  const StringRef PathSeparators = ":";
-#endif
-
-  SmallVector<StringRef, 8> LibDirs;
-  llvm::SplitString(OptPath.getValue(), LibDirs, PathSeparators);
-
-  for (const auto &LibDir : LibDirs) {
-    if (LibDir.empty())
-      continue;
-
-    SmallString<128> FilePath(LibDir);
-    llvm::sys::path::append(FilePath, Value);
-    if (llvm::sys::fs::exists(Twine(FilePath)))
-      return true;
-  }
-
-  return false;
-}
-
 /// \brief Check that the file referenced by Value exists. If it doesn't,
 /// issue a diagnostic and return false.
 static bool DiagnoseInputExistence(const Driver &D, const DerivedArgList &Args,
                                    StringRef Value) {
   if (!D.getCheckInputsExist())
     return true;
 
   // stdin always exists.
   if (Value == "-")
     return true;
 
   SmallString<64> Path(Value);
   if (Arg *WorkDir = Args.getLastArg(options::OPT_working_directory)) {
     if (!llvm::sys::path::is_absolute(Path.str())) {
       SmallString<64> Directory(WorkDir->getValue());
       llvm::sys::path::append(Directory, Value);
       Path.assign(Directory);
     }
   }
 
   if (llvm::sys::fs::exists(Twine(Path)))
     return true;
 
-  if (D.IsCLMode() && ExistsInLibDir(Value))
+  if (D.IsCLMode() && llvm::sys::Process::FindInEnvPath("LIB", Value))
     return true;
 
   D.Diag(clang::diag::err_drv_no_such_file) << Path.str();
   return false;
 }
 
 // Construct a the list of inputs and their types.
 void Driver::BuildInputs(const ToolChain &TC, DerivedArgList &Args,

lib/Driver/Tools.cpp

 // We do this special search to prevent clang-cl from falling back onto itself
 // if it's available as cl.exe on the path.
 static std::string FindFallback(const char *FallbackName,
                                 const char *ClangProgramPath) {
   llvm::Optional<std::string> OptPath = llvm::sys::Process::GetEnv("PATH");
   if (!OptPath.hasValue())
     return FallbackName;
 
-#ifdef LLVM_ON_WIN32
-  const StringRef PathSeparators = ";";
-#else
-  const StringRef PathSeparators = ":";
-#endif
-
+  const char EnvPathSeparatorStr[] = {llvm::sys::EnvPathSeparator, '\0'};
   SmallVector<StringRef, 8> PathSegments;
-  llvm::SplitString(OptPath.getValue(), PathSegments, PathSeparators);
+  llvm::SplitString(OptPath.getValue(), PathSegments, EnvPathSeparatorStr);
 
   for (size_t i = 0, e = PathSegments.size(); i != e; ++i) {
     const StringRef &PathSegment = PathSegments[i];
     if (PathSegment.empty())
       continue;
 
     SmallString<128> FilePath(PathSegment);
     llvm::sys::path::append(FilePath, FallbackName);
     if (llvm::sys::fs::can_execute(Twine(FilePath)) &&
         !llvm::sys::fs::equivalent(Twine(FilePath), ClangProgramPath))
       return FilePath.str();
   }
 
   return FallbackName;
 }
 
 Command *visualstudio::Compile::GetCommand(Compilation &C, const JobAction &JA,
                                            const InputInfo &Output,
                                            const InputInfoList &Inputs,
                                            const ArgList &Args,
                                            const char *LinkingOutput) const {
   ArgStringList CmdArgs;
   CmdArgs.push_back("/nologo");