src/hotspot/share/runtime/abstract_vm_version.hpp

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
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 *
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 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
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#ifndef SHARE_RUNTIME_ABSTRACT_VM_VERSION_HPP
#define SHARE_RUNTIME_ABSTRACT_VM_VERSION_HPP

#include "memory/allStatic.hpp"  // For declaration of class AllStatic
#include "utilities/globalDefinitions.hpp"

typedef enum {
  NoDetectedVirtualization,
  XenHVM,
  XenPVHVM, // mix-mode on Linux aarch64
  KVM,
  VMWare,
  HyperV,
  HyperVRole,
  PowerVM, // on AIX or Linux ppc64(le)
  PowerFullPartitionMode, // on Linux ppc64(le)
  PowerKVM
} VirtualizationType;

class outputStream;
enum class vmIntrinsicID;

// Abstract_VM_Version provides information about the VM.

class Abstract_VM_Version: AllStatic {
  friend class VMStructs;
  friend class JVMCIVMStructs;

 protected:
  static const char*  _s_vm_release;
  static const char*  _s_internal_vm_info_string;

  // CPU feature flags, can be affected by VM settings.
  static uint64_t _features;

  static const char* _features_string;

  static const char* _cpu_info_string;

  // Original CPU feature flags, not affected by VM settings.
  static uint64_t _cpu_features;

  // These are set by machine-dependent initializations
#ifndef SUPPORTS_NATIVE_CX8
  static bool         _supports_cx8;
#endif
  static bool         _supports_atomic_getset4;
  static bool         _supports_atomic_getset8;
  static bool         _supports_atomic_getadd4;
  static bool         _supports_atomic_getadd8;
  static unsigned int _logical_processors_per_package;
  static unsigned int _L1_data_cache_line_size;
  static int          _vm_major_version;
  static int          _vm_minor_version;
  static int          _vm_security_version;
  static int          _vm_patch_version;
  static int          _vm_build_number;
  static unsigned int _data_cache_line_flush_size;

 public:

  static VirtualizationType _detected_virtualization;

  // Called as part of the runtime services initialization which is
  // called from the management module initialization (via init_globals())
  // after argument parsing and attaching of the main thread has
  // occurred.  Examines a variety of the hardware capabilities of
  // the platform to determine which features can be used to execute the
  // program.
  static void initialize() { }

  // This allows for early initialization of VM_Version information
  // that may be needed later in the initialization sequence but before
  // full VM_Version initialization is possible. It can not depend on any
  // other part of the VM being initialized when called. Platforms that
  // need to specialize this define VM_Version::early_initialize().
  static void early_initialize() { }

  // Called to initialize VM variables needing initialization
  // after command line parsing. Platforms that need to specialize
  // this should define VM_Version::init_before_ergo().
  static void init_before_ergo() {}

  // Name
  static const char* vm_name();
  // Vendor
  static const char* vm_vendor();
  // VM version information string printed by launcher (java -version)
  static const char* vm_info_string();
  static const char* vm_release();
  static const char* vm_platform_string();
  static const char* vm_variant();

  static int vm_major_version()               { return _vm_major_version; }
  static int vm_minor_version()               { return _vm_minor_version; }
  static int vm_security_version()            { return _vm_security_version; }
  static int vm_patch_version()               { return _vm_patch_version; }
  static int vm_build_number()                { return _vm_build_number; }

  // Gets the jvm_version_info.jvm_version
  static unsigned int jvm_version();

  // Internal version providing additional build information
  static const char* internal_vm_info_string();
  static const char* jdk_debug_level();
  static const char* printable_jdk_debug_level();

  static const char* features_string() { return _features_string; }

  static const char* cpu_info_string() { return _cpu_info_string; }
  static const char* extract_features_string(const char* cpu_info_string,
                                             size_t cpu_info_string_len,
                                             size_t features_offset);

  static VirtualizationType get_detected_virtualization() {
    return _detected_virtualization;
  }

  // platforms that need to specialize this
  // define VM_Version::print_platform_virtualization_info()
  static void print_platform_virtualization_info(outputStream*) { }

  // does HW support an 8-byte compare-exchange operation?
  // Required to be true but still dynamically checked at runtime
  // for platforms that don't set SUPPORTS_NATIVE_CX8
  static bool supports_cx8()  {
#ifdef SUPPORTS_NATIVE_CX8
    return true;
#else
    return _supports_cx8;
#endif
  }
  // does HW support atomic get-and-set or atomic get-and-add?  Used
  // to guide intrinsification decisions for Unsafe atomic ops
  static bool supports_atomic_getset4()  {return _supports_atomic_getset4;}
  static bool supports_atomic_getset8()  {return _supports_atomic_getset8;}
  static bool supports_atomic_getadd4()  {return _supports_atomic_getadd4;}
  static bool supports_atomic_getadd8()  {return _supports_atomic_getadd8;}

  static unsigned int logical_processors_per_package() {
    return _logical_processors_per_package;
  }

  static unsigned int L1_data_cache_line_size() {
    return _L1_data_cache_line_size;
  }

  // the size in bytes of a data cache line flushed by a flush
  // operation which should be a power of two or zero if cache line
  // writeback is not supported by the current os_cpu combination
  static unsigned int data_cache_line_flush_size() {
    return _data_cache_line_flush_size;
  }

  // returns true if and only if cache line writeback is supported
  static bool supports_data_cache_line_flush() {
    return _data_cache_line_flush_size != 0;
  }

  // Denominator for computing default ParallelGCThreads for machines with
  // a large number of cores.
  static uint parallel_worker_threads_denominator() { return 8; }

  // Does this CPU support spin wait instruction?
  static bool supports_on_spin_wait() { return false; }

  // Does platform support fast class initialization checks for static methods?
  static bool supports_fast_class_init_checks() { return false; }

  // Does platform support stack watermark barriers for concurrent stack processing?
  constexpr static bool supports_stack_watermark_barrier() { return false; }

  // Is recursive lightweight locking implemented for this platform?
  constexpr static bool supports_recursive_lightweight_locking() { return false; }

  // Does platform support secondary supers table lookup?
  constexpr static bool supports_secondary_supers_table() { return false; }

  // Does platform support float16 instructions?
  static bool supports_float16() { return false; }

  // Does this CPU support this intrinsic?
  static bool is_intrinsic_supported(vmIntrinsicID id) { return true; }

  static bool profile_all_receivers_at_type_check() { return true; }

  static bool print_matching_lines_from_file(const char* filename, outputStream* st, const char* keywords_to_match[]);

 protected:
  // VM_Version statics
  static const size_t      CPU_TYPE_DESC_BUF_SIZE = 256;
  static const size_t      CPU_DETAILED_DESC_BUF_SIZE = 4096;

  static int   _no_of_threads;
  static int   _no_of_cores;
  static int   _no_of_sockets;
  static bool  _initialized;
  static char  _cpu_name[CPU_TYPE_DESC_BUF_SIZE];
  static char  _cpu_desc[CPU_DETAILED_DESC_BUF_SIZE];

 public:
  static int number_of_threads(void);
  static int number_of_cores(void);
  static int number_of_sockets(void);

  static const char* cpu_name(void);
  static const char* cpu_description(void);
};

#endif // SHARE_RUNTIME_ABSTRACT_VM_VERSION_HPP