Add loongarch64 Support (#314)

* Add macros for LOONGARCH hwcaps

* Update hwcaps.h

* LoongArch Support

* Remove unused definitions.

* Add ignored feature in test.

include/cpu_features_macros.h

@@ -83,6 +83,10 @@
 #define CPU_FEATURES_ARCH_RISCV128
 #endif
 
+#if defined(__loongarch64)
+#define CPU_FEATURES_ARCH_LOONGARCH
+#endif
+
 ////////////////////////////////////////////////////////////////////////////////
 // Os
 ////////////////////////////////////////////////////////////////////////////////

include/cpuinfo_loongarch.h

@@ -0,0 +1,77 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef CPU_FEATURES_INCLUDE_CPUINFO_LOONGARCH_H_
+#define CPU_FEATURES_INCLUDE_CPUINFO_LOONGARCH_H_
+
+#include "cpu_features_cache_info.h"
+#include "cpu_features_macros.h"
+
+#if !defined(CPU_FEATURES_ARCH_LOONGARCH)
+#error "Including cpuinfo_loongarch.h from a non-loongarch target."
+#endif
+
+CPU_FEATURES_START_CPP_NAMESPACE
+
+typedef struct {
+  // Base
+  int CPUCFG : 1;    // Instruction for Identify CPU Features 
+
+  // Extension
+  int LAM : 1;       // Extension for Atomic Memory Access Instructions
+  int UAL : 1;       // Extension for Non-Aligned Memory Access
+  int FPU : 1;       // Extension for Basic Floating-Point Instructions
+  int LSX : 1;       // Extension for Loongson SIMD eXtension
+  int LASX : 1;      // Extension for Loongson Advanced SIMD eXtension
+  int CRC32 : 1;     // Extension for Cyclic Redundancy Check Instructions
+  int COMPLEX : 1;   // Extension for Complex Vector Operation Instructions
+  int CRYPTO : 1;    // Extension for Encryption And Decryption Vector Instructions
+  int LVZ : 1;       // Extension for Virtualization
+  int LBT_X86 : 1;   // Extension for X86 Binary Translation Extension
+  int LBT_ARM : 1;   // Extension for ARM Binary Translation Extension
+  int LBT_MIPS : 1;  // Extension for MIPS Binary Translation Extension
+  int PTW : 1;       // Extension for Page Table Walker
+
+} LoongArchFeatures;
+
+typedef struct {
+  LoongArchFeatures features;
+} LoongArchInfo;
+
+typedef enum {
+  LOONGARCH_CPUCFG,
+  LOONGARCH_LAM,
+  LOONGARCH_UAL,
+  LOONGARCH_FPU,
+  LOONGARCH_LSX,
+  LOONGARCH_LASX,
+  LOONGARCH_CRC32,
+  LOONGARCH_COMPLEX,
+  LOONGARCH_CRYPTO,
+  LOONGARCH_LVZ,
+  LOONGARCH_LBT_X86,
+  LOONGARCH_LBT_ARM,
+  LOONGARCH_LBT_MIPS,
+  LOONGARCH_PTW,
+  LOONGARCH_LAST_,
+} LoongArchFeaturesEnum;
+
+LoongArchInfo GetLoongArchInfo(void);
+int GetLoongArchFeaturesEnumValue(const LoongArchFeatures* features,
+                              LoongArchFeaturesEnum value);
+const char* GetLoongArchFeaturesEnumName(LoongArchFeaturesEnum);
+
+CPU_FEATURES_END_CPP_NAMESPACE
+
+#endif  // CPU_FEATURES_INCLUDE_CPUINFO_LOONGARCH_H_

include/internal/hwcaps.h

@@ -237,6 +237,22 @@ CPU_FEATURES_START_CPP_NAMESPACE
 #define RISCV_HWCAP_C (1UL << ('C' - 'A'))
 #define RISCV_HWCAP_V (1UL << ('V' - 'A'))
 
+// https://github.com/torvalds/linux/blob/master/arch/loongarch/include/uapi/asm/hwcap.h
+#define HWCAP_LOONGARCH_CPUCFG   (1 << 0)
+#define HWCAP_LOONGARCH_LAM      (1 << 1)
+#define HWCAP_LOONGARCH_UAL      (1 << 2)
+#define HWCAP_LOONGARCH_FPU      (1 << 3)
+#define HWCAP_LOONGARCH_LSX      (1 << 4)
+#define HWCAP_LOONGARCH_LASX     (1 << 5)
+#define HWCAP_LOONGARCH_CRC32    (1 << 6)
+#define HWCAP_LOONGARCH_COMPLEX  (1 << 7)
+#define HWCAP_LOONGARCH_CRYPTO   (1 << 8)
+#define HWCAP_LOONGARCH_LVZ      (1 << 9)
+#define HWCAP_LOONGARCH_LBT_X86  (1 << 10)
+#define HWCAP_LOONGARCH_LBT_ARM  (1 << 11)
+#define HWCAP_LOONGARCH_LBT_MIPS (1 << 12)
+#define HWCAP_LOONGARCH_PTW      (1 << 13)
+
 typedef struct {
   unsigned long hwcaps;
   unsigned long hwcaps2;