[AArch64] Add default feature for CPUs on AArch64 target in Clang.

[kevin.qin]

Summary

For ARM target, we can use CRYPTO and CRC features if we select cortex-a57 by '-mcpu', but for AArch64 target, it doesn't work unless adding with '-mfpu=crypto-neon-fp-armv8'. The reason is, default feature for AArch64 target CPUs isn't set in front-end. To keep consistency between front-end and back-end and get end-users more easier to use, we'd better add default feature for CPUs on AArch64 target as well.

[t.p.northover]

Hi Kevin,

This looks sensible to me.

Cheers.

Tim.

lib/Basic/Targets.cpp

     NeonMode
   };
 
+  std::string CPU;
   unsigned FPU;
   unsigned CRC;
   unsigned Crypto;

                         .Cases("cortex-a53", "cortex-a57", true)
                         .Case("cyclone", true)
                         .Default(false);
+    if (CPUKnown)
+      CPU = Name;
     return CPUKnown;
   }
 

       (Feature == "neon" && FPU == NeonMode);
   }
 
+  void getDefaultFeatures(llvm::StringMap<bool> &Features) const override {
+
+  if (CPU == "cyclone") {
+    Features["fp-armv8"] = true;
+    Features["neon"] = true;
+    Features["crypto"] = true;
+    Features["crc"] = true;
+    Features["zcm"] = true;
+    Features["zcz"] = true;
+  } else if (CPU == "cortex-a53" || CPU == "cortex-a57") {
+    Features["fp-armv8"] = true;
+    Features["neon"] = true;
+    Features["crypto"] = true;
+    Features["crc"] = true;
+  }
+}
+
   bool handleTargetFeatures(std::vector<std::string> &Features,
                             DiagnosticsEngine &Diags) override {
     FPU = FPUMode;

test/Preprocessor/aarch64-target-features.c

 // RUN: %clang -target arm64-none-linux-gnu -mfpu=neon -x c -E -dM %s -o - | FileCheck --check-prefix=CHECK-NEON %s
 // CHECK-NEON: __ARM_NEON 1
 // CHECK-NEON: __ARM_NEON_FP 0xe
+
+// RUN: %clang -target aarch64-none-linux-gnu -mcpu=cortex-a53 -x c -E -dM %s -o - | FileCheck --check-prefix=CHECK-FEATURE %s
+// RUN: %clang -target aarch64-none-linux-gnu -mcpu=cortex-a57 -x c -E -dM %s -o - | FileCheck --check-prefix=CHECK-FEATURE %s
+// RUN: %clang -target aarch64-none-linux-gnu -mcpu=cyclone -x c -E -dM %s -o - | FileCheck --check-prefix=CHECK-FEATURE %s
+// CHECK-FEATURE: __ARM_FEATURE_CRC32 1
+// CHECK-FEATURE: __ARM_FEATURE_CRYPTO 1
+// CHECK-FEATURE: __ARM_NEON 1
+// CHECK-FEATURE: __ARM_NEON_FP 0xe
+
+