8278890: riscv: Missing features string in VM_Version

Reviewed-by: fyang

Author: Yadong Wang

src/hotspot/cpu/riscv/vm_version_riscv.cpp

@@ -32,9 +32,12 @@
 
 #include OS_HEADER_INLINE(os)
 
+const char* VM_Version::_uarch = "";
 uint32_t VM_Version::_initial_vector_length = 0;
 
-void VM_Version::get_processor_features() {
+void VM_Version::initialize() {
+  get_os_cpu_info();
+
   if (FLAG_IS_DEFAULT(UseFMA)) {
     FLAG_SET_DEFAULT(UseFMA, true);
   }
@@ -117,13 +120,23 @@ void VM_Version::get_processor_features() {
     FLAG_SET_DEFAULT(AvoidUnalignedAccesses, true);
   }
 
+  char buf[512];
+  buf[0] = '\0';
+  if (_uarch != NULL && strcmp(_uarch, "") != 0) snprintf(buf, sizeof(buf), "%s,", _uarch);
+  strcat(buf, "rv64");
+#define ADD_FEATURE_IF_SUPPORTED(id, name, bit) if (_features & CPU_##id) strcat(buf, name);
+  CPU_FEATURE_FLAGS(ADD_FEATURE_IF_SUPPORTED)
+#undef ADD_FEATURE_IF_SUPPORTED
+
+  _features_string = os::strdup(buf);
+
 #ifdef COMPILER2
-  get_c2_processor_features();
+  initialize_c2();
 #endif // COMPILER2
 }
 
 #ifdef COMPILER2
-void VM_Version::get_c2_processor_features() {
+void VM_Version::initialize_c2() {
   // lack of cmove in riscv64
   if (UseCMoveUnconditionally) {
     FLAG_SET_DEFAULT(UseCMoveUnconditionally, false);
@@ -164,11 +177,6 @@ void VM_Version::get_c2_processor_features() {
 }
 #endif // COMPILER2
 
-void VM_Version::initialize() {
-  get_cpu_info();
-  get_processor_features();
-}
-
 void VM_Version::initialize_cpu_information(void) {
   // do nothing if cpu info has been initialized
   if (_initialized) {

src/hotspot/cpu/riscv/vm_version_riscv.hpp

@@ -35,13 +35,13 @@
 class VM_Version : public Abstract_VM_Version {
 #ifdef COMPILER2
 private:
-  static void get_c2_processor_features();
+  static void initialize_c2();
 #endif // COMPILER2
 
 protected:
+  static const char* _uarch;
   static uint32_t _initial_vector_length;
-  static void get_processor_features();
-  static void get_cpu_info();
+  static void get_os_cpu_info();
   static uint32_t get_current_vector_length();
 
 public:
@@ -53,14 +53,14 @@ class VM_Version : public Abstract_VM_Version {
 
   enum Feature_Flag {
 #define CPU_FEATURE_FLAGS(decl)               \
-    decl(I,            "I",            8)     \
-    decl(M,            "M",           12)     \
-    decl(A,            "A",            0)     \
-    decl(F,            "F",            5)     \
-    decl(D,            "D",            3)     \
-    decl(C,            "C",            2)     \
-    decl(V,            "V",           21)     \
-    decl(B,            "B",            1)
+    decl(I,            "i",            8)     \
+    decl(M,            "m",           12)     \
+    decl(A,            "a",            0)     \
+    decl(F,            "f",            5)     \
+    decl(D,            "d",            3)     \
+    decl(C,            "c",            2)     \
+    decl(V,            "v",           21)     \
+    decl(B,            "b",            1)
 
 #define DECLARE_CPU_FEATURE_FLAG(id, name, bit) CPU_##id = (1 << bit),
     CPU_FEATURE_FLAGS(DECLARE_CPU_FEATURE_FLAG)

src/hotspot/os_cpu/linux_riscv/vm_version_linux_riscv.cpp

@@ -79,7 +79,7 @@ uint32_t VM_Version::get_current_vector_length() {
   return (uint32_t)read_csr(CSR_VLENB);
 }
 
-void VM_Version::get_cpu_info() {
+void VM_Version::get_os_cpu_info() {
 
   uint64_t auxv = getauxval(AT_HWCAP);
 
@@ -100,4 +100,19 @@ void VM_Version::get_cpu_info() {
       HWCAP_ISA_C |
       HWCAP_ISA_V |
       HWCAP_ISA_B);
+
+  if (FILE *f = fopen("/proc/cpuinfo", "r")) {
+    char buf[512], *p;
+    while (fgets(buf, sizeof (buf), f) != NULL) {
+      if ((p = strchr(buf, ':')) != NULL) {
+        if (strncmp(buf, "uarch", sizeof "uarch" - 1) == 0) {
+          char* uarch = os::strdup(p + 2);
+          uarch[strcspn(uarch, "\n")] = '\0';
+          _uarch = uarch;
+          break;
+        }
+      }
+    }
+    fclose(f);
+  }
 }