src/hotspot/cpu/aarch64/smallRegisterMap_aarch64.inline.hpp

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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#ifndef CPU_AARCH64_SMALLREGISTERMAP_AARCH64_INLINE_HPP
#define CPU_AARCH64_SMALLREGISTERMAP_AARCH64_INLINE_HPP

#include "runtime/frame.inline.hpp"
#include "runtime/registerMap.hpp"

// Java frames don't have callee saved registers (except for rfp), so we can use a smaller RegisterMap
class SmallRegisterMap {
  constexpr SmallRegisterMap() = default;
  ~SmallRegisterMap() = default;
  NONCOPYABLE(SmallRegisterMap);

public:
  static const SmallRegisterMap* instance() {
    static constexpr SmallRegisterMap the_instance{};
    return &the_instance;
  }
private:
  static void assert_is_rfp(VMReg r) NOT_DEBUG_RETURN
                                     DEBUG_ONLY({ assert (r == rfp->as_VMReg() || r == rfp->as_VMReg()->next(), "Reg: %s", r->name()); })
public:
  // as_RegisterMap is used when we didn't want to templatize and abstract over RegisterMap type to support SmallRegisterMap
  // Consider enhancing SmallRegisterMap to support those cases
  const RegisterMap* as_RegisterMap() const { return nullptr; }
  RegisterMap* as_RegisterMap() { return nullptr; }

  RegisterMap* copy_to_RegisterMap(RegisterMap* map, intptr_t* sp) const {
    map->clear();
    map->set_include_argument_oops(this->include_argument_oops());
    frame::update_map_with_saved_link(map, (intptr_t**)sp - frame::sender_sp_offset);
    return map;
  }

  inline address location(VMReg reg, intptr_t* sp) const {
    assert_is_rfp(reg);
    return (address)(sp - frame::sender_sp_offset);
  }

  inline void set_location(VMReg reg, address loc) { assert_is_rfp(reg); }

  JavaThread* thread() const {
  #ifndef ASSERT
    guarantee (false, "unreachable");
  #endif
    return nullptr;
  }

  bool update_map()    const { return false; }
  bool walk_cont()     const { return false; }
  bool include_argument_oops() const { return false; }
  void set_include_argument_oops(bool f)  {}
  bool in_cont()       const { return false; }
  stackChunkHandle stack_chunk() const { return stackChunkHandle(); }

#ifdef ASSERT
  bool should_skip_missing() const  { return false; }
  VMReg find_register_spilled_here(void* p, intptr_t* sp) { return rfp->as_VMReg(); }
  void print() const { print_on(tty); }
  void print_on(outputStream* st) const { st->print_cr("Small register map"); }
#endif
};

#endif // CPU_AARCH64_SMALLREGISTERMAP_AARCH64_INLINE_HPP