[Driver] Add -mllvm= as an alias for -mllvm

[MaskRay]

Summary

Similar to D131455 (-Xclang=). As well as making it convenient for some build
systems, this allows -Xarch_device '-mllvm=--inline-threshold=100' (and
-Xarch_host; so we don't need to allow space separators which are uncommon in
driver code).

Bear in mind that -mllvm options are unstable and should be avoided if possible.

[MaskRay]

fix test

[jhuber6]

This looks good. I've had similar problems when trying to pass things with arguments via the -Xarch or -Xopenmp-target= options.

[yaxunl]

LGTM. Thanks.

[Meinersbur]

This patch broke the Flang buildbot, e.g. https://lab.llvm.org/buildbot/#/builders/172/builds/23305

The tests
https://github.com/llvm/llvm-project/blob/main/flang/test/Driver/driver-help.f90
https://github.com/llvm/llvm-project/blob/main/flang/test/Driver/driver-help-hidden.f90

They check the entire output of -help and need to be updated for new options.

[MaskRay]

In D143325#4105356, @Meinersbur wrote:

This patch broke the Flang buildbot, e.g. https://lab.llvm.org/buildbot/#/builders/172/builds/23305

The tests
https://github.com/llvm/llvm-project/blob/main/flang/test/Driver/driver-help.f90
https://github.com/llvm/llvm-project/blob/main/flang/test/Driver/driver-help-hidden.f90

They check the entire output of -help and need to be updated for new options.

Thanks for the report. Already fixed by https://reviews.llvm.org/rG6a8a423c

clang/include/clang/Driver/Options.td

 def mios_simulator_version_min_EQ : Joined<["-"], "mios-simulator-version-min=">;
 def : Joined<["-"], "miphonesimulator-version-min=">, Alias<mios_simulator_version_min_EQ>;
 def mkernel : Flag<["-"], "mkernel">, Group<m_Group>;
 def mlinker_version_EQ : Joined<["-"], "mlinker-version=">,
   Flags<[NoXarchOption]>;
 def mllvm : Separate<["-"], "mllvm">,Flags<[CC1Option,CC1AsOption,CoreOption,FC1Option,FlangOption]>,
   HelpText<"Additional arguments to forward to LLVM's option processing">,
   MarshallingInfoStringVector<FrontendOpts<"LLVMArgs">>;
+def : Joined<["-"], "mllvm=">, Flags<[CoreOption,FlangOption]>, Alias<mllvm>,
+  HelpText<"Alias for -mllvm">, MetaVarName<"<arg>">;
 def mmlir : Separate<["-"], "mmlir">, Flags<[CoreOption,FC1Option,FlangOption]>,
   HelpText<"Additional arguments to forward to MLIR's option processing">;
 def ffuchsia_api_level_EQ : Joined<["-"], "ffuchsia-api-level=">,
   Group<m_Group>, Flags<[CC1Option]>, HelpText<"Set Fuchsia API level">,
   MarshallingInfoInt<LangOpts<"FuchsiaAPILevel">>;
 def mmacos_version_min_EQ : Joined<["-"], "mmacos-version-min=">,
   Group<m_Group>, HelpText<"Set macOS deployment target">;
 def : Joined<["-"], "mmacosx-version-min=">,

clang/test/Driver/hip-options.hip

 // PTH: "-cc1"{{.*}} "-fgpu-default-stream=per-thread" {{.*}}"-x" "hip-cpp-output"
 
 // RUN: %clang -### -x hip --target=x86_64-pc-windows-msvc -fms-extensions \
 // RUN:   -mllvm -amdgpu-early-inline-all=true  %s 2>&1 | \
 // RUN:   FileCheck -check-prefix=MLLVM %s
 // MLLVM-NOT: "-mllvm"{{.*}}"-amdgpu-early-inline-all=true"{{.*}}"-mllvm"{{.*}}"-amdgpu-early-inline-all=true"
 
 // RUN: %clang -### -Xarch_device -g -nogpulib --cuda-gpu-arch=gfx900 \
-// RUN:   -Xarch_device -fcf-protection=branch \
+// RUN:   -Xarch_device -fcf-protection=branch -Xarch_device -mllvm=--inline-threshold=100 \
 // RUN:   --cuda-gpu-arch=gfx906  %s 2>&1 | FileCheck -check-prefix=DEV %s
-// DEV: "-cc1"{{.*}} "-fcuda-is-device" {{.*}} "-debug-info-kind={{.*}}" {{.*}} "-fcf-protection=branch"
-// DEV: "-cc1"{{.*}} "-fcuda-is-device" {{.*}} "-debug-info-kind={{.*}}" {{.*}} "-fcf-protection=branch"
+// DEV: "-cc1"{{.*}} "-fcuda-is-device" {{.*}} "-debug-info-kind={{.*}}" {{.*}} "-fcf-protection=branch" {{.*}}"-mllvm" "--inline-threshold=100"
+// DEV: "-cc1"{{.*}} "-fcuda-is-device" {{.*}} "-debug-info-kind={{.*}}" {{.*}} "-fcf-protection=branch" {{.*}}"-mllvm" "--inline-threshold=100"
 // DEV-NOT: clang{{.*}} {{.*}} "-debug-info-kind={{.*}}"
 
 // RUN: %clang -### -Xarch_host -g -nogpulib --cuda-gpu-arch=gfx900 \
 // RUN:   --cuda-gpu-arch=gfx906  %s 2>&1 | FileCheck -check-prefix=HOST %s
 // HOST-NOT: "-fcuda-is-device" {{.*}} "-debug-info-kind={{.*}}"
 // HOST-NOT: "-fcuda-is-device" {{.*}} "-debug-info-kind={{.*}}"
 // HOST: clang{{.*}} "-debug-info-kind={{.*}}"