[Clang] Make enabling the new driver more generic

In preparation for allowing other offloading kinds to use the new driver
a new opt-in flag `-foffload-new-driver` is added. This is distinct from
the existing `-fopenmp-new-driver` because OpenMP will soon use the new
driver by default while the others should not.

Reviewed By: yaxunl, tra

Differential Revision: https://reviews.llvm.org/D123325

Author: jhuber6

clang/include/clang/Driver/Options.td

@@ -2534,10 +2534,14 @@ defm openmp_optimistic_collapse : BoolFOption<"openmp-optimistic-collapse",
   PosFlag<SetTrue, [CC1Option]>, NegFlag<SetFalse>, BothFlags<[NoArgumentUnused, HelpHidden]>>;
 def static_openmp: Flag<["-"], "static-openmp">,
   HelpText<"Use the static host OpenMP runtime while linking.">;
+def offload_new_driver : Flag<["--"], "offload-new-driver">, Flags<[CC1Option]>, Group<Action_Group>,
+  HelpText<"Use the new driver for offloading compilation.">;
+def no_offload_new_driver : Flag<["--"], "no-offload-new-driver">, Flags<[CC1Option]>, Group<Action_Group>,
+  HelpText<"Don't Use the new driver for offloading compilation.">;
 def fopenmp_new_driver : Flag<["-"], "fopenmp-new-driver">, Flags<[CC1Option]>, Group<Action_Group>,
   HelpText<"Use the new driver for OpenMP offloading.">;
 def fno_openmp_new_driver : Flag<["-"], "fno-openmp-new-driver">, Flags<[CC1Option]>, Group<Action_Group>,
-  HelpText<"Don't use the new driver for OpenMP offloading.">;
+  Alias<no_offload_new_driver>, HelpText<"Don't use the new driver for OpenMP offloading.">;
 def fno_optimize_sibling_calls : Flag<["-"], "fno-optimize-sibling-calls">, Group<f_Group>, Flags<[CC1Option]>,
   HelpText<"Disable tail call optimization, keeping the call stack accurate">,
   MarshallingInfoFlag<CodeGenOpts<"DisableTailCalls">>;

clang/lib/Driver/Driver.cpp

@@ -3976,17 +3976,19 @@ void Driver::BuildActions(Compilation &C, DerivedArgList &Args,
   // Builder to be used to build offloading actions.
   OffloadingActionBuilder OffloadBuilder(C, Args, Inputs);
 
+  bool UseNewOffloadingDriver =
+      (C.isOffloadingHostKind(Action::OFK_OpenMP) &&
+       Args.hasFlag(options::OPT_fopenmp_new_driver,
+                    options::OPT_no_offload_new_driver, true)) ||
+      Args.hasFlag(options::OPT_offload_new_driver,
+                   options::OPT_no_offload_new_driver, false);
+
   // Construct the actions to perform.
   HeaderModulePrecompileJobAction *HeaderModuleAction = nullptr;
   ExtractAPIJobAction *ExtractAPIAction = nullptr;
   ActionList LinkerInputs;
   ActionList MergerInputs;
 
-  bool UseNewOffloadingDriver =
-      C.isOffloadingHostKind(Action::OFK_OpenMP) &&
-      Args.hasFlag(options::OPT_fopenmp_new_driver,
-                   options::OPT_fno_openmp_new_driver, true);
-
   for (auto &I : Inputs) {
     types::ID InputType = I.first;
     const Arg *InputArg = I.second;
@@ -4114,8 +4116,7 @@ void Driver::BuildActions(Compilation &C, DerivedArgList &Args,
     // Check if this Linker Job should emit a static library.
     if (ShouldEmitStaticLibrary(Args)) {
       LA = C.MakeAction<StaticLibJobAction>(LinkerInputs, types::TY_Image);
-    } else if (UseNewOffloadingDriver &&
-               C.getActiveOffloadKinds() != Action::OFK_None) {
+    } else if (UseNewOffloadingDriver) {
       LA = C.MakeAction<LinkerWrapperJobAction>(LinkerInputs, types::TY_Image);
       LA->propagateHostOffloadInfo(C.getActiveOffloadKinds(),
                                    /*BoundArch=*/nullptr);

clang/lib/Driver/ToolChains/Clang.cpp

@@ -4389,8 +4389,11 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   bool IsDeviceOffloadAction = !(JA.isDeviceOffloading(Action::OFK_None) ||
                                  JA.isDeviceOffloading(Action::OFK_Host));
   bool IsHostOffloadingAction =
-      JA.isHostOffloading(Action::OFK_OpenMP) &&
-      !Args.hasArg(options::OPT_fno_openmp_new_driver);
+      (JA.isHostOffloading(Action::OFK_OpenMP) &&
+       Args.hasFlag(options::OPT_fopenmp_new_driver,
+                    options::OPT_no_offload_new_driver, true)) ||
+      Args.hasFlag(options::OPT_offload_new_driver,
+                   options::OPT_no_offload_new_driver, false);
   bool IsUsingLTO = D.isUsingLTO(IsDeviceOffloadAction);
   auto LTOMode = D.getLTOMode(IsDeviceOffloadAction);
 
@@ -4686,7 +4689,9 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
       // Only AMDGPU supports device-side LTO.
       if (IsDeviceOffloadAction &&
           !Args.hasFlag(options::OPT_fopenmp_new_driver,
-                        options::OPT_fno_openmp_new_driver, true) &&
+                        options::OPT_no_offload_new_driver, true) &&
+          !Args.hasFlag(options::OPT_offload_new_driver,
+                        options::OPT_no_offload_new_driver, false) &&
           !Triple.isAMDGPU()) {
         D.Diag(diag::err_drv_unsupported_opt_for_target)
             << Args.getLastArg(options::OPT_foffload_lto,