[clang][Driver] Support -fms-volatile as equivalent to /volatile:ms (#74790)

The flag -fms-volatile has existed as a -cc1 flag for a while. It also
technically existed as a driver flag, but didn't do anything because it
wasn't wired up to anything in the driver.

This patch adds -fno-ms-volatile, and makes both -fms-volatile and
-fno-ms-volatile work the same way as the cl-mode flags. The defaults
are unchanged (default on for x86 in cl mode, default off otherwise).

Author: efriedma-quic

clang/include/clang/Driver/Options.td

@@ -2896,9 +2896,11 @@ defm asm_blocks : BoolFOption<"asm-blocks",
   LangOpts<"AsmBlocks">, Default<fms_extensions.KeyPath>,
   PosFlag<SetTrue, [], [ClangOption, CC1Option]>,
   NegFlag<SetFalse>>;
-def fms_volatile : Flag<["-"], "fms-volatile">, Group<f_Group>,
-  Visibility<[ClangOption, CC1Option]>,
-  MarshallingInfoFlag<LangOpts<"MSVolatile">>;
+defm ms_volatile : BoolFOption<"ms-volatile",
+  LangOpts<"MSVolatile">, DefaultFalse,
+  PosFlag<SetTrue, [], [ClangOption, CC1Option],
+          "Volatile loads and stores have acquire and release semantics">,
+  NegFlag<SetFalse>>;
 def fmsc_version : Joined<["-"], "fmsc-version=">, Group<f_Group>,
   Visibility<[ClangOption, CLOption]>,
   HelpText<"Microsoft compiler version number to report in _MSC_VER (0 = don't define it (default))">;
@@ -8217,7 +8219,7 @@ def _SLASH_winsysroot : CLJoinedOrSeparate<"winsysroot">,
   HelpText<"Same as \"/diasdkdir <dir>/DIA SDK\" /vctoolsdir <dir>/VC/Tools/MSVC/<vctoolsversion> \"/winsdkdir <dir>/Windows Kits/10\"">,
   MetaVarName<"<dir>">;
 def _SLASH_volatile_iso : Option<["/", "-"], "volatile:iso", KIND_FLAG>,
-  Group<_SLASH_volatile_Group>, Flags<[NoXarchOption]>, Visibility<[CLOption]>,
+  Visibility<[CLOption]>, Alias<fno_ms_volatile>,
   HelpText<"Volatile loads and stores have standard semantics">;
 def _SLASH_vmb : CLFlag<"vmb">,
   HelpText<"Use a best-case representation method for member pointers">;
@@ -8232,7 +8234,7 @@ def _SLASH_vmv : CLFlag<"vmv">,
   HelpText<"Set the default most-general representation to "
            "virtual inheritance">;
 def _SLASH_volatile_ms  : Option<["/", "-"], "volatile:ms", KIND_FLAG>,
-  Group<_SLASH_volatile_Group>, Flags<[NoXarchOption]>, Visibility<[CLOption]>,
+  Visibility<[CLOption]>, Alias<fms_volatile>,
   HelpText<"Volatile loads and stores have acquire and release semantics">;
 def _SLASH_clang : CLJoined<"clang:">,
   HelpText<"Pass <arg> to the clang driver">, MetaVarName<"<arg>">;

clang/lib/Driver/ToolChains/Clang.cpp

@@ -5615,6 +5615,10 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
                        options::OPT_fno_auto_import);
   }
 
+  if (Args.hasFlag(options::OPT_fms_volatile, options::OPT_fno_ms_volatile,
+                   Triple.isX86() && D.IsCLMode()))
+    CmdArgs.push_back("-fms-volatile");
+
   // Non-PIC code defaults to -fdirect-access-external-data while PIC code
   // defaults to -fno-direct-access-external-data. Pass the option if different
   // from the default.
@@ -7947,18 +7951,6 @@ void Clang::AddClangCLArgs(const ArgList &Args, types::ID InputType,
     CmdArgs.push_back("-P");
   }
 
-  unsigned VolatileOptionID;
-  if (getToolChain().getTriple().isX86())
-    VolatileOptionID = options::OPT__SLASH_volatile_ms;
-  else
-    VolatileOptionID = options::OPT__SLASH_volatile_iso;
-
-  if (Arg *A = Args.getLastArg(options::OPT__SLASH_volatile_Group))
-    VolatileOptionID = A->getOption().getID();
-
-  if (VolatileOptionID == options::OPT__SLASH_volatile_ms)
-    CmdArgs.push_back("-fms-volatile");
-
  if (Args.hasFlag(options::OPT__SLASH_Zc_dllexportInlines_,
                   options::OPT__SLASH_Zc_dllexportInlines,
                   false)) {

clang/test/Driver/cl-options.c

@@ -272,10 +272,12 @@
 // RUN: not %clang_cl /vmg /vmm /vms -### -- %s 2>&1 | FileCheck -check-prefix=VMX %s
 // VMX: '/vms' not allowed with '/vmm'
 
-// RUN: %clang_cl /volatile:iso -### -- %s 2>&1 | FileCheck -check-prefix=VOLATILE-ISO %s
+// RUN: %clang_cl --target=i686-pc-win32 /volatile:iso -### -- %s 2>&1 | FileCheck -check-prefix=VOLATILE-ISO %s
+// RUN: %clang_cl --target=aarch64-pc-win32 -### -- %s 2>&1 | FileCheck -check-prefix=VOLATILE-ISO %s
 // VOLATILE-ISO-NOT: "-fms-volatile"
 
-// RUN: %clang_cl /volatile:ms -### -- %s 2>&1 | FileCheck -check-prefix=VOLATILE-MS %s
+// RUN: %clang_cl --target=aarch64-pc-win32 /volatile:ms -### -- %s 2>&1 | FileCheck -check-prefix=VOLATILE-MS %s
+// RUN: %clang_cl --target=i686-pc-win32 -### -- %s 2>&1 | FileCheck -check-prefix=VOLATILE-MS %s
 // VOLATILE-MS: "-fms-volatile"
 
 // RUN: %clang_cl /W0 -### -- %s 2>&1 | FileCheck -check-prefix=W0 %s

clang/test/Driver/clang_f_opts.c

@@ -611,3 +611,9 @@
 // CHECK-INT-OBJEMITTER-NOT: unsupported option '-fintegrated-objemitter' for target
 // RUN: not %clang -### -fno-integrated-objemitter --target=x86_64 %s 2>&1 | FileCheck -check-prefix=CHECK-NOINT-OBJEMITTER %s
 // CHECK-NOINT-OBJEMITTER: unsupported option '-fno-integrated-objemitter' for target
+
+// RUN: %clang -### --target=aarch64-windows-msvc %s 2>&1 | FileCheck -check-prefix=CHECK-NO-MS-VOLATILE %s
+// RUN: %clang -### --target=aarch64-windows-msvc -fms-volatile %s 2>&1 | FileCheck -check-prefix=CHECK-MS-VOLATILE %s
+// RUN: %clang -### --target=aarch64-windows-msvc -fno-ms-volatile %s 2>&1 | FileCheck -check-prefix=CHECK-NO-MS-VOLATILE %s
+// CHECK-MS-VOLATILE: -fms-volatile
+// CHECK-NO-MS-VOLATILE-NOT: -fms-volatile