hotspot source code - jvm stack frame

vm/runtime/frame.hpp 第54行，关于栈帧操作的系列方法定义，源码如下：

class CodeBlob;
class FrameValues;
class vframeArray;


// A frame represents a physical stack frame (an activation).  Frames
// can be C or Java frames, and the Java frames can be interpreted or
// compiled.  In contrast, vframes represent source-level activations,
// so that one physical frame can correspond to multiple source level
// frames because of inlining.

class frame VALUE_OBJ_CLASS_SPEC {
 private:
  // Instance variables:
  intptr_t* _sp; // stack pointer (from Thread::last_Java_sp)
  address   _pc; // program counter (the next instruction after the call)

  CodeBlob* _cb; // CodeBlob that "owns" pc
  enum deopt_state {
    not_deoptimized,
    is_deoptimized,
    unknown
  };

  deopt_state _deopt_state;

 public:
  // Constructors
  frame();

#ifndef PRODUCT
  // This is a generic constructor which is only used by pns() in debug.cpp.
  // pns (i.e. print native stack) uses this constructor to create a starting
  // frame for stack walking. The implementation of this constructor is platform
  // dependent (i.e. SPARC doesn't need an 'fp' argument an will ignore it) but
  // we want to keep the signature generic because pns() is shared code.
  frame(void* sp, void* fp, void* pc);
#endif

  // Accessors

  // pc: Returns the pc at which this frame will continue normally.
  // It must point at the beginning of the next instruction to execute.
  address pc() const             { return _pc; }

  // This returns the pc that if you were in the debugger you'd see. Not
  // the idealized value in the frame object. This undoes the magic conversion
  // that happens for deoptimized frames. In addition it makes the value the
  // hardware would want to see in the native frame. The only user (at this point)
  // is deoptimization. It likely no one else should ever use it.
  address raw_pc() const;

  void set_pc( address   newpc );

  intptr_t* sp() const           { return _sp; }
  void set_sp( intptr_t* newsp ) { _sp = newsp; }


  CodeBlob* cb() const           { return _cb; }

  // patching operations
  void   patch_pc(Thread* thread, address pc);

  // Every frame needs to return a unique id which distinguishes it from all other frames.
  // For sparc and ia32 use sp. ia64 can have memory frames that are empty so multiple frames
  // will have identical sp values. For ia64 the bsp (fp) value will serve. No real frame
  // should have an id() of NULL so it is a distinguishing value for an unmatchable frame.
  // We also have relationals which allow comparing a frame to anoth frame's id() allow
  // us to distinguish younger (more recent activation) from older (less recent activations)
  // A NULL id is only valid when comparing for equality.

  intptr_t* id(void) const;
  bool is_younger(intptr_t* id) const;
  bool is_older(intptr_t* id) const;

  // testers

  // Compares for strict equality. Rarely used or needed.
  // It can return a different result than f1.id() == f2.id()
  bool equal(frame other) const;

  // type testers
  bool is_interpreted_frame()    const;
  bool is_java_frame()           const;
  bool is_entry_frame()          const;             // Java frame called from C?
  bool is_stub_frame()           const;
  bool is_ignored_frame()        const;
  bool is_native_frame()         const;
  bool is_runtime_frame()        const;
  bool is_compiled_frame()       const;
  bool is_safepoint_blob_frame() const;
  bool is_deoptimized_frame()    const;

  // testers
  bool is_first_frame() const; // oldest frame? (has no sender)
  bool is_first_java_frame() const;              // same for Java frame

  bool is_interpreted_frame_valid(JavaThread* thread) const;       // performs sanity checks on interpreted frames.

  // tells whether this frame is marked for deoptimization
  bool should_be_deoptimized() const;

  // tells whether this frame can be deoptimized
  bool can_be_deoptimized() const;

  // returns the frame size in stack slots
  int frame_size(RegisterMap* map) const;

  // returns the sending frame
  frame sender(RegisterMap* map) const;

  // for Profiling - acting on another frame. walks sender frames
  // if valid.
  frame profile_find_Java_sender_frame(JavaThread *thread);
  bool safe_for_sender(JavaThread *thread);

  // returns the sender, but skips conversion frames
  frame real_sender(RegisterMap* map) const;

  // returns the the sending Java frame, skipping any intermediate C frames
  // NB: receiver must not be first frame
  frame java_sender() const;

 private:
  // Helper methods for better factored code in frame::sender
  frame sender_for_compiled_frame(RegisterMap* map) const;
  frame sender_for_entry_frame(RegisterMap* map) const;
  frame sender_for_interpreter_frame(RegisterMap* map) const;
  frame sender_for_native_frame(RegisterMap* map) const;

  // All frames:

  // A low-level interface for vframes:

 public:

  intptr_t* addr_at(int index) const             { return &fp()[index];    }
  intptr_t  at(int index) const                  { return *addr_at(index); }

  // accessors for locals
  oop obj_at(int offset) const                   { return *obj_at_addr(offset);  }
  void obj_at_put(int offset, oop value)         { *obj_at_addr(offset) = value; }

  jint int_at(int offset) const                  { return *int_at_addr(offset);  }
  void int_at_put(int offset, jint value)        { *int_at_addr(offset) = value; }

  oop*      obj_at_addr(int offset) const        { return (oop*)     addr_at(offset); }

  oop*      adjusted_obj_at_addr(Method* method, int index) { return obj_at_addr(adjust_offset(method, index)); }

 private:
  jint*    int_at_addr(int offset) const         { return (jint*)    addr_at(offset); }

 public:
  // Link (i.e., the pointer to the previous frame)
  intptr_t* link() const;
  void set_link(intptr_t* addr);

  // Return address
  address  sender_pc() const;

  // Support for deoptimization
  void deoptimize(JavaThread* thread);

  // The frame's original SP, before any extension by an interpreted callee;
  // used for packing debug info into vframeArray objects and vframeArray lookup.
  intptr_t* unextended_sp() const;

  // returns the stack pointer of the calling frame
  intptr_t* sender_sp() const;

  // Returns the real 'frame pointer' for the current frame.
  // This is the value expected by the platform ABI when it defines a
  // frame pointer register. It may differ from the effective value of
  // the FP register when that register is used in the JVM for other
  // purposes (like compiled frames on some platforms).
  // On other platforms, it is defined so that the stack area used by
  // this frame goes from real_fp() to sp().
  intptr_t* real_fp() const;

  // Deoptimization info, if needed (platform dependent).
  // Stored in the initial_info field of the unroll info, to be used by
  // the platform dependent deoptimization blobs.
  intptr_t *initial_deoptimization_info();

  // Interpreter frames:

 private:
  intptr_t** interpreter_frame_locals_addr() const;
  intptr_t*  interpreter_frame_bcx_addr() const;
  intptr_t*  interpreter_frame_mdx_addr() const;

 public:
  // Locals

  // The _at version returns a pointer because the address is used for GC.
  intptr_t* interpreter_frame_local_at(int index) const;

  void interpreter_frame_set_locals(intptr_t* locs);

  // byte code index/pointer (use these functions for unchecked frame access only!)
  intptr_t interpreter_frame_bcx() const                  { return *interpreter_frame_bcx_addr(); }
  void interpreter_frame_set_bcx(intptr_t bcx);

  // byte code index
  jint interpreter_frame_bci() const;
  void interpreter_frame_set_bci(jint bci);

  // byte code pointer
  address interpreter_frame_bcp() const;
  void    interpreter_frame_set_bcp(address bcp);

  // Unchecked access to the method data index/pointer.
  // Only use this if you know what you are doing.
  intptr_t interpreter_frame_mdx() const                  { return *interpreter_frame_mdx_addr(); }
  void interpreter_frame_set_mdx(intptr_t mdx);

  // method data pointer
  address interpreter_frame_mdp() const;
  void    interpreter_frame_set_mdp(address dp);

  // Find receiver out of caller's (compiled) argument list
  oop retrieve_receiver(RegisterMap *reg_map);

  // Return the monitor owner and BasicLock for compiled synchronized
  // native methods so that biased locking can revoke the receiver's
  // bias if necessary.  This is also used by JVMTI's GetLocalInstance method
  // (via VM_GetReceiver) to retrieve the receiver from a native wrapper frame.
  BasicLock* get_native_monitor();
  oop        get_native_receiver();

  // Find receiver for an invoke when arguments are just pushed on stack (i.e., callee stack-frame is
  // not setup)
  oop interpreter_callee_receiver(Symbol* signature)     { return *interpreter_callee_receiver_addr(signature); }


  oop* interpreter_callee_receiver_addr(Symbol* signature);


  // expression stack (may go up or down, direction == 1 or -1)
 public:
  intptr_t* interpreter_frame_expression_stack() const;
  static  jint  interpreter_frame_expression_stack_direction();

  // The _at version returns a pointer because the address is used for GC.
  intptr_t* interpreter_frame_expression_stack_at(jint offset) const;

  // top of expression stack
  intptr_t* interpreter_frame_tos_at(jint offset) const;
  intptr_t* interpreter_frame_tos_address() const;


  jint  interpreter_frame_expression_stack_size() const;

  intptr_t* interpreter_frame_sender_sp() const;

#ifndef CC_INTERP
  // template based interpreter deoptimization support
  void  set_interpreter_frame_sender_sp(intptr_t* sender_sp);
  void interpreter_frame_set_monitor_end(BasicObjectLock* value);
#endif // CC_INTERP

  // Address of the temp oop in the frame. Needed as GC root.
  oop* interpreter_frame_temp_oop_addr() const;

  // BasicObjectLocks:
  //
  // interpreter_frame_monitor_begin is higher in memory than interpreter_frame_monitor_end
  // Interpreter_frame_monitor_begin points to one element beyond the oldest one,
  // interpreter_frame_monitor_end   points to the youngest one, or if there are none,
  //                                 it points to one beyond where the first element will be.
  // interpreter_frame_monitor_size  reports the allocation size of a monitor in the interpreter stack.
  //                                 this value is >= BasicObjectLock::size(), and may be rounded up

  BasicObjectLock* interpreter_frame_monitor_begin() const;
  BasicObjectLock* interpreter_frame_monitor_end()   const;
  BasicObjectLock* next_monitor_in_interpreter_frame(BasicObjectLock* current) const;
  BasicObjectLock* previous_monitor_in_interpreter_frame(BasicObjectLock* current) const;
  static int interpreter_frame_monitor_size();

  void interpreter_frame_verify_monitor(BasicObjectLock* value) const;

  // Tells whether the current interpreter_frame frame pointer
  // corresponds to the old compiled/deoptimized fp
  // The receiver used to be a top level frame
  bool interpreter_frame_equals_unpacked_fp(intptr_t* fp);

  // Return/result value from this interpreter frame
  // If the method return type is T_OBJECT or T_ARRAY populates oop_result
  // For other (non-T_VOID) the appropriate field in the jvalue is populated
  // with the result value.
  // Should only be called when at method exit when the method is not
  // exiting due to an exception.
  BasicType interpreter_frame_result(oop* oop_result, jvalue* value_result);

 public:
  // Method & constant pool cache
  Method* interpreter_frame_method() const;
  void interpreter_frame_set_method(Method* method);
  Method** interpreter_frame_method_addr() const;
  ConstantPoolCache** interpreter_frame_cache_addr() const;

 public:
  // Entry frames
  JavaCallWrapper* entry_frame_call_wrapper() const { return *entry_frame_call_wrapper_addr(); }
  JavaCallWrapper* entry_frame_call_wrapper_if_safe(JavaThread* thread) const;
  JavaCallWrapper** entry_frame_call_wrapper_addr() const;
  intptr_t* entry_frame_argument_at(int offset) const;

  // tells whether there is another chunk of Delta stack above
  bool entry_frame_is_first() const;

  // Compiled frames:

 public:
  // Given the index of a local, and the number of argument words
  // in this stack frame, tell which word of the stack frame to find
  // the local in.  Arguments are stored above the ofp/rpc pair,
  // while other locals are stored below it.
  // Since monitors (BasicLock blocks) are also assigned indexes,
  // but may have different storage requirements, their presence
  // can also affect the calculation of offsets.
  static int local_offset_for_compiler(int local_index, int nof_args, int max_nof_locals, int max_nof_monitors);

  // Given the index of a monitor, etc., tell which word of the
  // stack frame contains the start of the BasicLock block.
  // Note that the local index by convention is the __higher__
  // of the two indexes allocated to the block.
  static int monitor_offset_for_compiler(int local_index, int nof_args, int max_nof_locals, int max_nof_monitors);

  // Tell the smallest value that local_offset_for_compiler will attain.
  // This is used to help determine how much stack frame to allocate.
  static int min_local_offset_for_compiler(int nof_args, int max_nof_locals, int max_nof_monitors);

  // Tells if this register must be spilled during a call.
  // On Intel, all registers are smashed by calls.
  static bool volatile_across_calls(Register reg);

cpu/x86/vm/bytecodeInterpreter_x86.hpp 第69行，定义了javaStack和javaLocals相关的操作，源码如下：

// JavaStack Implementation

#define GET_STACK_SLOT(offset)    (*((intptr_t*) &topOfStack[-(offset)]))
#define STACK_SLOT(offset)    ((address) &topOfStack[-(offset)])
#define STACK_ADDR(offset)    (*((address *) &topOfStack[-(offset)]))
#define STACK_INT(offset)     (*((jint*) &topOfStack[-(offset)]))
#define STACK_FLOAT(offset)   (*((jfloat *) &topOfStack[-(offset)]))
#define STACK_OBJECT(offset)  (*((oop *) &topOfStack [-(offset)]))
#define STACK_DOUBLE(offset)  (((VMJavaVal64*) &topOfStack[-(offset)])->d)
#define STACK_LONG(offset)    (((VMJavaVal64 *) &topOfStack[-(offset)])->l)

#define SET_STACK_SLOT(value, offset)   (*(intptr_t*)&topOfStack[-(offset)] = *(intptr_t*)(value))
#define SET_STACK_ADDR(value, offset)   (*((address *)&topOfStack[-(offset)]) = (value))
#define SET_STACK_INT(value, offset)    (*((jint *)&topOfStack[-(offset)]) = (value))
#define SET_STACK_FLOAT(value, offset)  (*((jfloat *)&topOfStack[-(offset)]) = (value))
#define SET_STACK_OBJECT(value, offset) (*((oop *)&topOfStack[-(offset)]) = (value))
#define SET_STACK_DOUBLE(value, offset) (((VMJavaVal64*)&topOfStack[-(offset)])->d = (value))
#define SET_STACK_DOUBLE_FROM_ADDR(addr, offset) (((VMJavaVal64*)&topOfStack[-(offset)])->d =  \
                                                 ((VMJavaVal64*)(addr))->d)
#define SET_STACK_LONG(value, offset)   (((VMJavaVal64*)&topOfStack[-(offset)])->l = (value))
#define SET_STACK_LONG_FROM_ADDR(addr, offset)   (((VMJavaVal64*)&topOfStack[-(offset)])->l =  \
                                                 ((VMJavaVal64*)(addr))->l)
// JavaLocals implementation

#define LOCALS_SLOT(offset)    ((intptr_t*)&locals[-(offset)])
#define LOCALS_ADDR(offset)    ((address)locals[-(offset)])
#define LOCALS_INT(offset)     ((jint)(locals[-(offset)]))
#define LOCALS_FLOAT(offset)   (*((jfloat*)&locals[-(offset)]))
#define LOCALS_OBJECT(offset)  (cast_to_oop(locals[-(offset)]))
#define LOCALS_DOUBLE(offset)  (((VMJavaVal64*)&locals[-((offset) + 1)])->d)
#define LOCALS_LONG(offset)    (((VMJavaVal64*)&locals[-((offset) + 1)])->l)
#define LOCALS_LONG_AT(offset) (((address)&locals[-((offset) + 1)]))
#define LOCALS_DOUBLE_AT(offset) (((address)&locals[-((offset) + 1)]))

#define SET_LOCALS_SLOT(value, offset)    (*(intptr_t*)&locals[-(offset)] = *(intptr_t *)(value))
#define SET_LOCALS_ADDR(value, offset)    (*((address *)&locals[-(offset)]) = (value))
#define SET_LOCALS_INT(value, offset)     (*((jint *)&locals[-(offset)]) = (value))
#define SET_LOCALS_FLOAT(value, offset)   (*((jfloat *)&locals[-(offset)]) = (value))
#define SET_LOCALS_OBJECT(value, offset)  (*((oop *)&locals[-(offset)]) = (value))
#define SET_LOCALS_DOUBLE(value, offset)  (((VMJavaVal64*)&locals[-((offset)+1)])->d = (value))
#define SET_LOCALS_LONG(value, offset)    (((VMJavaVal64*)&locals[-((offset)+1)])->l = (value))
#define SET_LOCALS_DOUBLE_FROM_ADDR(addr, offset) (((VMJavaVal64*)&locals[-((offset)+1)])->d = \
                                                  ((VMJavaVal64*)(addr))->d)
#define SET_LOCALS_LONG_FROM_ADDR(addr, offset) (((VMJavaVal64*)&locals[-((offset)+1)])->l = \
                                                ((VMJavaVal64*)(addr))->l)

cpu/x86/vm/frame_x86.hpp 第31行，描述了frame的数据结构，源码如下：

// A frame represents a physical stack frame (an activation).  Frames can be
// C or Java frames, and the Java frames can be interpreted or compiled.
// In contrast, vframes represent source-level activations, so that one physical frame
// can correspond to multiple source level frames because of inlining.
// A frame is comprised of {pc, fp, sp}
// ------------------------------ Asm interpreter ----------------------------------------
// Layout of asm interpreter frame:
//    [expression stack      ] * <- sp
//    [monitors              ]   \
//     ...                        | monitor block size
//    [monitors              ]   /
//    [monitor block size    ]
//    [byte code index/pointr]                   = bcx()                bcx_offset
//    [pointer to locals     ]                   = locals()             locals_offset
//    [constant pool cache   ]                   = cache()              cache_offset
//    [methodData            ]                   = mdp()                mdx_offset
//    [Method*               ]                   = method()             method_offset
//    [last sp               ]                   = last_sp()            last_sp_offset
//    [old stack pointer     ]                     (sender_sp)          sender_sp_offset
//    [old frame pointer     ]   <- fp           = link()
//    [return pc             ]
//    [oop temp              ]                     (only for native calls)
//    [locals and parameters ]
//                               <- sender sp
// ------------------------------ Asm interpreter ----------------------------------------

// ------------------------------ C++ interpreter ----------------------------------------
//
// Layout of C++ interpreter frame: (While executing in BytecodeInterpreter::run)
//
//                             <- SP (current esp/rsp)
//    [local variables         ] BytecodeInterpreter::run local variables
//    ...                        BytecodeInterpreter::run local variables
//    [local variables         ] BytecodeInterpreter::run local variables
//    [old frame pointer       ]   fp [ BytecodeInterpreter::run's ebp/rbp ]
//    [return pc               ]  (return to frame manager)
//    [interpreter_state*      ]  (arg to BytecodeInterpreter::run)   --------------
//    [expression stack        ] <- last_Java_sp                           |
//    [...                     ] * <- interpreter_state.stack              |
//    [expression stack        ] * <- interpreter_state.stack_base         |
//    [monitors                ]   \                                       |
//     ...                          | monitor block size                   |
//    [monitors                ]   / <- interpreter_state.monitor_base     |
//    [struct interpretState   ] <-----------------------------------------|
//    [return pc               ] (return to callee of frame manager [1]
//    [locals and parameters   ]
//                               <- sender sp

// [1] When the C++ interpreter calls a new method it returns to the frame
//     manager which allocates a new frame on the stack. In that case there
//     is no real callee of this newly allocated frame. The frame manager is
//     aware of the additional frame(s) and will pop them as nested calls
//     complete. However, to make it look good in the debugger the frame
//     manager actually installs a dummy pc pointing to RecursiveInterpreterActivation
//     with a fake interpreter_state* parameter to make it easy to debug
//     nested calls.

// Note that contrary to the layout for the assembly interpreter the
// expression stack allocated for the C++ interpreter is full sized.
// However this is not as bad as it seems as the interpreter frame_manager
// will truncate the unused space on successive method calls.
//
// ------------------------------ C++ interpreter ----------------------------------------

 public:
  enum {
    pc_return_offset                                 =  0,
    // All frames
    link_offset                                      =  0,
    return_addr_offset                               =  1,
    // non-interpreter frames
    sender_sp_offset                                 =  2,

#ifndef CC_INTERP

    // Interpreter frames
    interpreter_frame_result_handler_offset          =  3, // for native calls only
    interpreter_frame_oop_temp_offset                =  2, // for native calls only

    interpreter_frame_sender_sp_offset               = -1,
    // outgoing sp before a call to an invoked method
    interpreter_frame_last_sp_offset                 = interpreter_frame_sender_sp_offset - 1,
    interpreter_frame_method_offset                  = interpreter_frame_last_sp_offset - 1,
    interpreter_frame_mdx_offset                     = interpreter_frame_method_offset - 1,
    interpreter_frame_cache_offset                   = interpreter_frame_mdx_offset - 1,
    interpreter_frame_locals_offset                  = interpreter_frame_cache_offset - 1,
    interpreter_frame_bcx_offset                     = interpreter_frame_locals_offset - 1,
    interpreter_frame_initial_sp_offset              = interpreter_frame_bcx_offset - 1,

    interpreter_frame_monitor_block_top_offset       = interpreter_frame_initial_sp_offset,
    interpreter_frame_monitor_block_bottom_offset    = interpreter_frame_initial_sp_offset,

#endif // CC_INTERP

References

1. vm/runtime/frame.hpp
2. cpu/x86/vm/bytecodeInterpreter_x86.hpp
3. cpu/x86/vm/frame_x86.hpp