HostFeatures: Detect FlagM/2

Currently unused but at least detect the feature so that our Arm64 JIT
can use it in the future.

FEXCore/Source/Interface/Config/Config.json.in

@@ -76,7 +76,11 @@
           "ENABLEATOMICS": "enableatomics",
           "DISABLEATOMICS": "disableatomics",
           "ENABLEFCMA": "enablefcma",
-          "DISABLEFCMA": "disablefcma"
+          "DISABLEFCMA": "disablefcma",
+          "ENABLEFLAGM": "enableflagm",
+          "DISABLEFLAGM": "disableflagm",
+          "ENABLEFLAGM2": "enableflagm2",
+          "DISABLEFLAGM2": "disableflagm2"
         },
         "Desc": [
           "Allows controlling of the CPU features in the JIT.",
@@ -91,7 +95,9 @@
           "\t{enable,disable}rng: Will force enable or disable rng even if the host doesn't support it",
           "\t{enable,disable}clzero: Will force enable or disable clzero even if the host doesn't support it",
           "\t{enable,disable}atomics: Will force enable or disable ARMv8.1 LSE atomics even if the host doesn't support it",
-          "\t{enable,disable}fcma: Will force enable or disable fcma even if the host doesn't support it"
+          "\t{enable,disable}fcma: Will force enable or disable fcma even if the host doesn't support it",
+          "\t{enable,disable}flagm: Will force enable or disable flagm even if the host doesn't support it",
+          "\t{enable,disable}flagm2: Will force enable or disable flagm2 even if the host doesn't support it"
         ]
       }
     },

FEXCore/Source/Interface/Core/HostFeatures.cpp

@@ -100,6 +100,14 @@ static void OverrideFeatures(HostFeatures *Features) {
   const bool EnableFCMA = HostFeatures() & FEXCore::Config::HostFeatures::ENABLEFCMA;
   LogMan::Throw::AFmt(!(DisableFCMA && EnableFCMA), "Disabling and Enabling CPU features are mutually exclusive");
 
+  const bool DisableFlagM = HostFeatures() & FEXCore::Config::HostFeatures::DISABLEFLAGM;
+  const bool EnableFlagM = HostFeatures() & FEXCore::Config::HostFeatures::ENABLEFLAGM;
+  LogMan::Throw::AFmt(!(DisableFlagM && EnableFlagM), "Disabling and Enabling CPU features are mutually exclusive");
+
+  const bool DisableFlagM2 = HostFeatures() & FEXCore::Config::HostFeatures::DISABLEFLAGM2;
+  const bool EnableFlagM2 = HostFeatures() & FEXCore::Config::HostFeatures::ENABLEFLAGM2;
+  LogMan::Throw::AFmt(!(DisableFlagM2 && EnableFlagM2), "Disabling and Enabling CPU features are mutually exclusive");
+
   if (EnableAVX) {
     Features->SupportsAVX = true;
   }
@@ -166,6 +174,18 @@ static void OverrideFeatures(HostFeatures *Features) {
   else if (DisableFCMA) {
     Features->SupportsFCMA = false;
   }
+  if (EnableFlagM) {
+    Features->SupportsFlagM = true;
+  }
+  else if (DisableFlagM) {
+    Features->SupportsFlagM = false;
+  }
+  if (EnableFlagM2) {
+    Features->SupportsFlagM2 = true;
+  }
+  else if (DisableFlagM2) {
+    Features->SupportsFlagM2 = false;
+  }
 }
 
 HostFeatures::HostFeatures() {
@@ -192,6 +212,8 @@ HostFeatures::HostFeatures() {
   SupportsPMULL_128Bit = Features.Has(vixl::CPUFeatures::Feature::kPmull1Q);
   SupportsCSSC = Features.Has(vixl::CPUFeatures::Feature::kCSSC);
   SupportsFCMA = Features.Has(vixl::CPUFeatures::Feature::kFcma);
+  SupportsFlagM = Features.Has(vixl::CPUFeatures::Feature::kFlagM);
+  SupportsFlagM2 = Features.Has(vixl::CPUFeatures::Feature::kAXFlag);
 
   Supports3DNow = true;
   SupportsSSE4A = true;

FEXCore/include/FEXCore/Core/HostFeatures.h

@@ -32,6 +32,8 @@ class HostFeatures final {
     bool SupportsPMULL_128Bit{};
     bool SupportsCSSC{};
     bool SupportsFCMA{};
+    bool SupportsFlagM{};
+    bool SupportsFlagM2{};
 
     // Float exception behaviour
     bool SupportsFlushInputsToZero{};