[OpenMP] Remove use of removed '-f[no-]openmp-new-driver' flag

[jhuber6]

Summary

The changes in D130020 removed all support for the old method of
compiling OpenMP offloading programs. This means that
-fopenmp-new-driver has no effect and -fno-openmp-new-driver does
not work. This patch removes the use and documentation of this flag.
Note that the --offload-new-driver flag still exists for using the new
driver optionally with CUDA and HIP.

[tra]

clang/lib/Driver/Driver.cpp

3906

The option still exists in the Options.td file. Should it be removed?

[jhuber6]

clang/lib/Driver/Driver.cpp

3906

Generally we don't remove the options once they've been defined (between releases), as this would result in some applications failing to compile after switching from LLVM 15 to LLVM 16 for example. If we just leave it there then it will exist as a warning saying that the flag was unused.

[tra]

clang/lib/Driver/Driver.cpp

3906

SGTM.

clang/docs/ClangCommandLineReference.rst

 .. option:: -fopenmp-extensions, -fno-openmp-extensions
 
 Enable all Clang extensions for OpenMP directives and clauses
 
 .. option:: -fopenmp-implicit-rpath, -fno-openmp-implicit-rpath
 
 Set rpath on OpenMP executables
 
-.. option:: -fopenmp-new-driver
-
-Use the new driver for OpenMP offloading.
-
 .. option:: -fopenmp-offload-mandatory
 
 Do not create a host fallback if offloading to the device fails.
 
 .. option:: -fopenmp-simd, -fno-openmp-simd
 
 Emit OpenMP code only for SIMD-based constructs.
 

clang/lib/Driver/Driver.cpp

void Driver::BuildActions(Compilation &C, DerivedArgList &Args,
   }
 
   handleArguments(C, Args, Inputs, Actions);
 
   // 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)) ||
+      C.isOffloadingHostKind(Action::OFK_OpenMP) ||
       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;

clang/lib/Driver/ToolChains/Clang.cpp

void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   bool IsHIP = JA.isOffloading(Action::OFK_HIP);
   bool IsHIPDevice = JA.isDeviceOffloading(Action::OFK_HIP);
   bool IsOpenMPDevice = JA.isDeviceOffloading(Action::OFK_OpenMP);
   bool IsHeaderModulePrecompile = isa<HeaderModulePrecompileJobAction>(JA);
   bool IsExtractAPI = isa<ExtractAPIJobAction>(JA);
   bool IsDeviceOffloadAction = !(JA.isDeviceOffloading(Action::OFK_None) ||
                                  JA.isDeviceOffloading(Action::OFK_Host));
   bool IsHostOffloadingAction =
-      (JA.isHostOffloading(Action::OFK_OpenMP) &&
-       Args.hasFlag(options::OPT_fopenmp_new_driver,
-                    options::OPT_no_offload_new_driver, true)) ||
+      JA.isHostOffloading(Action::OFK_OpenMP) ||
       (JA.isHostOffloading(C.getActiveOffloadKinds()) &&
        Args.hasFlag(options::OPT_offload_new_driver,
                     options::OPT_no_offload_new_driver, false));
 
   bool IsRDCMode =
       Args.hasFlag(options::OPT_fgpu_rdc, options::OPT_fno_gpu_rdc, false);
   bool IsUsingLTO = D.isUsingLTO(IsDeviceOffloadAction);
   auto LTOMode = D.getLTOMode(IsDeviceOffloadAction);
if (isa<AnalyzeJobAction>(JA)) {
     // loading the bitcode up in 'opt' or 'llc' and running passes gives the
     // same result as running passes here.  For LTO, we don't need to preserve
     // the use-list order, since serialization to bitcode is part of the flow.
     if (JA.getType() == types::TY_LLVM_BC)
       CmdArgs.push_back("-emit-llvm-uselists");
 
     if (IsUsingLTO) {
       // Only AMDGPU supports device-side LTO.
-      if (IsDeviceOffloadAction &&
-          !Args.hasFlag(options::OPT_fopenmp_new_driver,
-                        options::OPT_no_offload_new_driver, true) &&
+      if (IsDeviceOffloadAction && !JA.isHostOffloading(Action::OFK_OpenMP) &&
           !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,
                                options::OPT_foffload_lto_EQ)
                    ->getAsString(Args)
             << Triple.getTriple();

clang/test/Driver/amdgpu-openmp-toolchain.c

 // CHECK-BINDINGS: "amdgcn-amd-amdhsa" - "clang", inputs: ["[[INPUT]]", "[[HOST_BC]]"], output: "[[DEVICE_BC:.+]]"
 // CHECK-BINDINGS: "x86_64-unknown-linux-gnu" - "Offload::Packager", inputs: ["[[DEVICE_BC]]"], output: "[[BINARY:.+]]"
 // CHECK-BINDINGS: "x86_64-unknown-linux-gnu" - "clang", inputs: ["[[HOST_BC]]", "[[BINARY]]"], output: "[[HOST_OBJ:.+]]"
 // CHECK-BINDINGS: "x86_64-unknown-linux-gnu" - "Offload::Linker", inputs: ["[[HOST_OBJ]]"], output: "a.out"
 
 // RUN:   %clang -### --target=x86_64-unknown-linux-gnu -emit-llvm -S -fopenmp -fopenmp-targets=amdgcn-amd-amdhsa -Xopenmp-target=amdgcn-amd-amdhsa -march=gfx803 -nogpulib %s 2>&1 | FileCheck %s --check-prefix=CHECK-EMIT-LLVM-IR
 // CHECK-EMIT-LLVM-IR: "-cc1" "-triple" "amdgcn-amd-amdhsa"{{.*}}"-emit-llvm"
 
-// RUN: %clang -### -target x86_64-pc-linux-gnu -fopenmp -fopenmp-targets=amdgcn-amd-amdhsa -Xopenmp-target=amdgcn-amd-amdhsa -march=gfx803 -lm --rocm-device-lib-path=%S/Inputs/rocm/amdgcn/bitcode -fopenmp-new-driver %s 2>&1 | FileCheck %s --check-prefix=CHECK-LIB-DEVICE-NEW
+// RUN: %clang -### -target x86_64-pc-linux-gnu -fopenmp -fopenmp-targets=amdgcn-amd-amdhsa -Xopenmp-target=amdgcn-amd-amdhsa -march=gfx803 -lm --rocm-device-lib-path=%S/Inputs/rocm/amdgcn/bitcode %s 2>&1 | FileCheck %s --check-prefix=CHECK-LIB-DEVICE-NEW
 // CHECK-LIB-DEVICE-NEW: {{.*}}clang-linker-wrapper{{.*}}--bitcode-library=openmp-amdgcn-amd-amdhsa-gfx803={{.*}}ocml.bc"{{.*}}ockl.bc"{{.*}}oclc_daz_opt_on.bc"{{.*}}oclc_unsafe_math_off.bc"{{.*}}oclc_finite_only_off.bc"{{.*}}oclc_correctly_rounded_sqrt_on.bc"{{.*}}oclc_wavefrontsize64_on.bc"{{.*}}oclc_isa_version_803.bc"