[Driver] move DragonFly header search path management to the driver

[brad]

Summary

As has been done for other OS's. Move the header path management to the driver.

Also I noticed with https://reviews.llvm.org/D89690 that the library paths were updated for GCC 8, but
the C++ header path was not. So I also fixed that while here.

[brad]

Also use concat() in addLibStdCxxIncludePaths().

[brad]

Rebase.

[brad]

David? Frederic?

[brad]

Remove C_INCLUDE_DIRS bits.

[MaskRay]

clang/lib/Lex/InitHeaderSearch.cpp

331

5.0 becomes 8.0 after move?

[brad]

clang/lib/Lex/InitHeaderSearch.cpp

331

5.0 becomes 8.0 after move?

Read what the summary says. The current path is wrong.

[MaskRay]

Looks great!

clang/lib/Lex/InitHeaderSearch.cpp

331

Thank you! If this has been broken for so long, it means they don't care about libstdc++? I think we can just remove the include path...

clang/lib/Driver/ToolChains/DragonFly.h

 
 class LLVM_LIBRARY_VISIBILITY DragonFly : public Generic_ELF {
 public:
   DragonFly(const Driver &D, const llvm::Triple &Triple,
             const llvm::opt::ArgList &Args);
 
   bool IsMathErrnoDefault() const override { return false; }
 
+  void
+  AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
+                            llvm::opt::ArgStringList &CC1Args) const override;
+  void addLibStdCxxIncludePaths(
+      const llvm::opt::ArgList &DriverArgs,
+      llvm::opt::ArgStringList &CC1Args) const override;
+
 protected:
   Tool *buildAssembler() const override;
   Tool *buildLinker() const override;
 };
 
 } // end namespace toolchains
 } // end namespace driver
 } // end namespace clang
 
 #endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_DRAGONFLY_H

clang/lib/Driver/ToolChains/DragonFly.cpp

 //===--- DragonFly.cpp - DragonFly ToolChain Implementations ----*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #include "DragonFly.h"
 #include "CommonArgs.h"
+#include "clang/Config/config.h"
 #include "clang/Driver/Compilation.h"
 #include "clang/Driver/Driver.h"
 #include "clang/Driver/Options.h"
 #include "llvm/Option/ArgList.h"
+#include "llvm/Support/Path.h"
 
 using namespace clang::driver;
 using namespace clang::driver::tools;
 using namespace clang::driver::toolchains;
 using namespace clang;
 using namespace llvm::opt;
 
 /// DragonFly Tools
DragonFly::DragonFly(const Driver &D, const llvm::Triple &Triple,
   if (getDriver().getInstalledDir() != getDriver().Dir)
     getProgramPaths().push_back(getDriver().Dir);
 
   getFilePaths().push_back(getDriver().Dir + "/../lib");
   getFilePaths().push_back("/usr/lib");
   getFilePaths().push_back("/usr/lib/gcc80");
 }
 
+void DragonFly::AddClangSystemIncludeArgs(
+    const llvm::opt::ArgList &DriverArgs,
+    llvm::opt::ArgStringList &CC1Args) const {
+  const Driver &D = getDriver();
+
+  if (DriverArgs.hasArg(clang::driver::options::OPT_nostdinc))
+    return;
+
+  if (!DriverArgs.hasArg(options::OPT_nobuiltininc)) {
+    SmallString<128> Dir(D.ResourceDir);
+    llvm::sys::path::append(Dir, "include");
+    addSystemInclude(DriverArgs, CC1Args, Dir.str());
+  }
+
+  if (DriverArgs.hasArg(options::OPT_nostdlibinc))
+    return;
+
+  // Check for configure-time C include directories.
+  StringRef CIncludeDirs(C_INCLUDE_DIRS);
+  if (CIncludeDirs != "") {
+    SmallVector<StringRef, 5> dirs;
+    CIncludeDirs.split(dirs, ":");
+    for (StringRef dir : dirs) {
+      StringRef Prefix =
+          llvm::sys::path::is_absolute(dir) ? StringRef(D.SysRoot) : "";
+      addExternCSystemInclude(DriverArgs, CC1Args, Prefix + dir);
+    }
+    return;
+  }
+
+  addExternCSystemInclude(DriverArgs, CC1Args,
+                          concat(D.SysRoot, "/usr/include"));
+}
+
+void DragonFly::addLibStdCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
+                                         llvm::opt::ArgStringList &CC1Args) const {
+  addLibStdCXXIncludePaths(concat(getDriver().SysRoot, "/usr/include/c++/8.0"), "", "",
+                           DriverArgs, CC1Args);
+}
+
 Tool *DragonFly::buildAssembler() const {
   return new tools::dragonfly::Assembler(*this);
 }
 
 Tool *DragonFly::buildLinker() const {
   return new tools::dragonfly::Linker(*this);
 }

clang/lib/Lex/InitHeaderSearch.cpp

       // Cygwin-1.7
       AddMinGWCPlusPlusIncludePaths("/usr/lib/gcc", "i686-pc-cygwin", "4.7.3");
       AddMinGWCPlusPlusIncludePaths("/usr/lib/gcc", "i686-pc-cygwin", "4.5.3");
       AddMinGWCPlusPlusIncludePaths("/usr/lib/gcc", "i686-pc-cygwin", "4.3.4");
       // g++-4 / Cygwin-1.5
       AddMinGWCPlusPlusIncludePaths("/usr/lib/gcc", "i686-pc-cygwin", "4.3.2");
       break;
     }
     break;
-  case llvm::Triple::DragonFly:
-    AddPath("/usr/include/c++/5.0", CXXSystem, false);
-    break;
   case llvm::Triple::Minix:
     AddGnuCPlusPlusIncludePaths("/usr/gnu/include/c++/4.4.3",
                                 "", "", "", triple);
     break;
   default:
     break;
   }
 }
 
 bool InitHeaderSearch::ShouldAddDefaultIncludePaths(
     const llvm::Triple &triple) {
   switch (triple.getOS()) {
   case llvm::Triple::AIX:
+  case llvm::Triple::DragonFly:
   case llvm::Triple::Emscripten:
   case llvm::Triple::FreeBSD:
   case llvm::Triple::NetBSD:
   case llvm::Triple::OpenBSD:
   case llvm::Triple::PS4:
   case llvm::Triple::PS5:
   case llvm::Triple::Fuchsia:
   case llvm::Triple::Haiku: