8368950: RISC-V: fail to catch out of order declarations among dependent cpu extensions/flags

src/hotspot/cpu/riscv/vm_version_riscv.hpp

@@ -64,10 +64,13 @@ class VM_Version : public Abstract_VM_Version {
     virtual void disable_feature() {
       _value = -1;
     }
-    const char* pretty()         { return _pretty; }
-    uint64_t feature_bit()       { return _linux_feature_bit; }
-    bool feature_string()        { return _feature_string; }
-    int64_t value()              { return _value; }
+    const char* pretty()          { return _pretty; }
+    uint64_t feature_bit()        { return _linux_feature_bit; }
+    bool feature_string()         { return _feature_string; }
+    int64_t value()               { return _value; }
+    // For non-ext flags, they don't have dependency relationship among each other,
+    // in this situation, just return the default value -1.
+    virtual int dependent_index() { return -1; }
     virtual bool enabled() = 0;
     virtual void update_flag() = 0;
 
@@ -99,6 +102,26 @@ class VM_Version : public Abstract_VM_Version {
       }
       va_end(va);
     }
+
+    void verify_deps(RVFeatureValue* dep0, ...) {
+      assert(dep0 != nullptr, "must not");
+      assert(dependent_index() >= 0, "must");
+
+      va_list va;
+      va_start(va, dep0);
+      RVFeatureValue* next = dep0;
+      while (next != nullptr) {
+        assert(next->dependent_index() >= 0, "must");
+        // We only need to check depenency relationship for extension flags.
+        // The dependant ones must be declared before this, for example, v must be declared
+        // before Zvfh in RV_EXT_FEATURE_FLAGS. The reason is in setup_cpu_available_features
+        // we need to make sure v is `update_flag`ed before Zvfh, so Zvfh is `update_flag`ed
+        // based on v.
+        assert(dependent_index() > next->dependent_index(), "Invalid");
+        next = va_arg(va, RVFeatureValue*);
+      }
+      va_end(va);
+    }
   };
 
   #define UPDATE_DEFAULT(flag)           \
@@ -117,8 +140,9 @@ class VM_Version : public Abstract_VM_Version {
   #define UPDATE_DEFAULT_DEP(flag, dep0, ...)                                                               \
   void update_flag() {                                                                                      \
       assert(enabled(), "Must be.");                                                                        \
+      verify_deps(dep0, ##__VA_ARGS__);                                                                     \
       if (FLAG_IS_DEFAULT(flag)) {                                                                          \
-        if (this->deps_all_enabled(dep0, ##__VA_ARGS__)) {                                                  \
+        if (deps_all_enabled(dep0, ##__VA_ARGS__)) {                                                        \
           FLAG_SET_DEFAULT(flag, true);                                                                     \
         } else {                                                                                            \
           FLAG_SET_DEFAULT(flag, false);                                                                    \
@@ -154,6 +178,11 @@ class VM_Version : public Abstract_VM_Version {
       RVFeatureValue(pretty, linux_bit_num, fstring),
       _cpu_feature_index(cpu_feature_index) {
     }
+    int dependent_index() {
+      // Use _cpu_feature_index as dependent_index, it can be used to check for example v is declared
+      // before Zvfh in RV_EXT_FEATURE_FLAGS.
+      return _cpu_feature_index;
+    }
     bool enabled() {
       return RVExtFeatures::current()->support_feature(_cpu_feature_index);
     }