[Driver] Mark m_x86_Features_Group options as TargetSpecific

[MaskRay]

Summary

so that they lead to an error when compiled for non-x86 targets.
Follow-up to D151590.

% aarch64-linux-gnu-gcc -c -mavx a.c
aarch64-linux-gnu-gcc: error: unrecognized command-line option ‘-mavx’
% clang --target=aarch64-unknown-linux-gnu -c -mavx a.c  # without this patch
clang: warning: argument unused during compilation: '-mavx' [-Wunused-command-line-argument]
...

% clang --target=aarch64-unknown-linux-gnu -c -mavx a.c  # with this patch
clang: error: unsupported option '-mavx' for target 'aarch64-unknown-linux-gnu'

As a workaround for https://github.com/llvm/llvm-project/issues/63270, we don't
report an error for -msse4.2.

[skan]

LGTM

clang/include/clang/Driver/Options.td

foreach i = {0-6} in
   def ffixed_a#i : Flag<["-"], "ffixed-a"#i>, Group<m_m68k_Features_Group>,
     HelpText<"Reserve the a"#i#" register (M68k only)">;
 foreach i = {0-7} in
   def ffixed_d#i : Flag<["-"], "ffixed-d"#i>, Group<m_m68k_Features_Group>,
     HelpText<"Reserve the d"#i#" register (M68k only)">;
 } // let Flags = [TargetSpecific]
 
 // X86 feature flags
+let Flags = [TargetSpecific] in {
 def mx87 : Flag<["-"], "mx87">, Group<m_x86_Features_Group>;
 def mno_x87 : Flag<["-"], "mno-x87">, Group<m_x86_Features_Group>;
 def m80387 : Flag<["-"], "m80387">, Alias<mx87>;
 def mno_80387 : Flag<["-"], "mno-80387">, Alias<mno_x87>;
 def mno_fp_ret_in_387 : Flag<["-"], "mno-fp-ret-in-387">, Alias<mno_x87>;
 def mmmx : Flag<["-"], "mmmx">, Group<m_x86_Features_Group>;
 def mno_mmx : Flag<["-"], "mno-mmx">, Group<m_x86_Features_Group>;
 def m3dnow : Flag<["-"], "m3dnow">, Group<m_x86_Features_Group>;

 def msse2 : Flag<["-"], "msse2">, Group<m_x86_Features_Group>;
 def mno_sse2 : Flag<["-"], "mno-sse2">, Group<m_x86_Features_Group>;
 def msse3 : Flag<["-"], "msse3">, Group<m_x86_Features_Group>;
 def mno_sse3 : Flag<["-"], "mno-sse3">, Group<m_x86_Features_Group>;
 def mssse3 : Flag<["-"], "mssse3">, Group<m_x86_Features_Group>;
 def mno_ssse3 : Flag<["-"], "mno-ssse3">, Group<m_x86_Features_Group>;
 def msse4_1 : Flag<["-"], "msse4.1">, Group<m_x86_Features_Group>;
 def mno_sse4_1 : Flag<["-"], "mno-sse4.1">, Group<m_x86_Features_Group>;
+} // let Flags = [TargetSpecific]
+// TODO: Make -msse4.2 TargetSpecific after
+// https://github.com/llvm/llvm-project/issues/63270 is fixed.
 def msse4_2 : Flag<["-"], "msse4.2">, Group<m_x86_Features_Group>;
+let Flags = [TargetSpecific] in {
 def mno_sse4_2 : Flag<["-"], "mno-sse4.2">, Group<m_x86_Features_Group>;
 def msse4 : Flag<["-"], "msse4">, Alias<msse4_2>;
 // -mno-sse4 turns off sse4.1 which has the effect of turning off everything
 // later than 4.1. -msse4 turns on 4.2 which has the effect of turning on
 // everything earlier than 4.2.
 def mno_sse4 : Flag<["-"], "mno-sse4">, Alias<mno_sse4_1>;
 def msse4a : Flag<["-"], "msse4a">, Group<m_x86_Features_Group>;
 def mno_sse4a : Flag<["-"], "mno-sse4a">, Group<m_x86_Features_Group>;

 def mxsaves : Flag<["-"], "mxsaves">, Group<m_x86_Features_Group>;
 def mno_xsaves : Flag<["-"], "mno-xsaves">, Group<m_x86_Features_Group>;
 def mshstk : Flag<["-"], "mshstk">, Group<m_x86_Features_Group>;
 def mno_shstk : Flag<["-"], "mno-shstk">, Group<m_x86_Features_Group>;
 def mretpoline_external_thunk : Flag<["-"], "mretpoline-external-thunk">, Group<m_x86_Features_Group>;
 def mno_retpoline_external_thunk : Flag<["-"], "mno-retpoline-external-thunk">, Group<m_x86_Features_Group>;
 def mvzeroupper : Flag<["-"], "mvzeroupper">, Group<m_x86_Features_Group>;
 def mno_vzeroupper : Flag<["-"], "mno-vzeroupper">, Group<m_x86_Features_Group>;
+} // let Flags = [TargetSpecific]
 
 // These are legacy user-facing driver-level option spellings. They are always
 // aliases for options that are spelled using the more common Unix / GNU flag
 // style of double-dash and equals-joined flags.
 def target_legacy_spelling : Separate<["-"], "target">,
                              Alias<target>,
                              Flags<[CoreOption]>;
 

clang/test/Driver/x86-target-features.c

 // AVXVNNIINT16: "-target-feature" "+avxvnniint16"
 // NO-AVXVNNIINT16: "-target-feature" "-avxvnniint16"
 
 // RUN: %clang --target=i386 -march=i386 -mcrc32 %s -### 2>&1 | FileCheck -check-prefix=CRC32 %s
 // RUN: %clang --target=i386 -march=i386 -mno-crc32 %s -### 2>&1 | FileCheck -check-prefix=NO-CRC32 %s
 // CRC32: "-target-feature" "+crc32"
 // NO-CRC32: "-target-feature" "-crc32"
 
+// RUN: not %clang -### --target=aarch64 -mcrc32 -msse4.1 -msse4.2 -mno-sgx %s 2>&1 | FileCheck --check-prefix=NONX86 %s
+// NONX86:      error: unsupported option '-mcrc32' for target 'aarch64'
+// NONX86-NEXT: error: unsupported option '-msse4.1' for target 'aarch64'
+/// TODO: This warning is a workaround for https://github.com/llvm/llvm-project/issues/63270
+// NONX86-NEXT: warning: argument unused during compilation: '-msse4.2' [-Wunused-command-line-argument]
+// NONX86-NEXT: error: unsupported option '-mno-sgx' for target 'aarch64'
+
 // RUN: %clang --target=i386 -march=i386 -mharden-sls=return %s -### -o %t.o 2>&1 | FileCheck -check-prefixes=SLS-RET,NO-SLS %s
 // RUN: %clang --target=i386 -march=i386 -mharden-sls=indirect-jmp %s -### -o %t.o 2>&1 | FileCheck -check-prefixes=SLS-IJMP,NO-SLS %s
 // RUN: %clang --target=i386 -march=i386 -mharden-sls=none -mharden-sls=all %s -### -o %t.o 2>&1 | FileCheck -check-prefixes=SLS-IJMP,SLS-RET %s
 // RUN: %clang --target=i386 -march=i386 -mharden-sls=all -mharden-sls=none %s -### -o %t.o 2>&1 | FileCheck -check-prefix=NO-SLS %s
 // RUN: not %clang --target=i386 -march=i386 -mharden-sls=return,indirect-jmp %s -### -o %t.o 2>&1 | FileCheck -check-prefix=BAD-SLS %s
 // NO-SLS-NOT: "+harden-sls-
 // SLS-RET-DAG: "-target-feature" "+harden-sls-ret"
 // SLS-IJMP-DAG: "-target-feature" "+harden-sls-ijmp"
 // NO-SLS-NOT: "+harden-sls-
 // BAD-SLS: unsupported argument '{{[^']+}}' to option '-mharden-sls='
 
 // RUN: touch %t.o
 // RUN: %clang -fdriver-only -Werror --target=x86_64-pc-linux-gnu -mharden-sls=all %t.o -o /dev/null 2>&1 | count 0