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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

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#include "runtime/synchronizer.hpp"

// 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, sp, younger_sp}

// Layout of asm interpreter frame:

//

//  0xfffffff

//  ......

// [last  extra incoming arg,  (local # Nargs > 6 ? Nargs-1 : undef)]

// .. Note: incoming args are copied to local frame area upon entry

// [first extra incoming arg,  (local # Nargs > 6 ? 6       : undef)]

// [6 words for C-arg storage (unused)] Are this and next one really needed?

// [C-aggregate-word (unused)] Yes, if want extra params to be  in same place as C convention

// [16 words for register saving]                                    <--- FP

// [interpreter_frame_vm_locals ] (see below)

//              Note: Llocals is always double-word aligned

// [first local i.e. local # 0]        <-- Llocals

// ...

// [last local, i.e. local # Nlocals-1]

// [monitors                 ]

// ....

// [monitors                 ]    <-- Lmonitors (same as Llocals + 6*4 if none)

//                                    (must be double-word aligned because

//                                     monitor element size is constrained to

//                                     doubleword)

//

//                                <-- Lesp (points 1 past TOS)

// [bottom word used for stack ]

// ...

// [top word used for stack]    (first word of stack is double-word aligned)

// [space for outgoing args (conservatively allocated as max_stack - 6 + interpreter_frame_extra_outgoing_argument_words)]

// [6 words for C-arg storage]

// [C-aggregate-word (unused)]

// [16 words for register saving]                                    <--- SP

// ...

// 0x0000000

//

// The in registers and local registers are preserved in a block at SP.

//

// The first six in registers (I0..I5) hold the first six locals.

// The locals are used as follows:

//    Lesp         first free element of expression stack

//                 (which grows towards __higher__ addresses)

//    Lbcp         is set to address of bytecode to execute

//                 It may at times (during GC) be an index instead.

//    Lmethod      the method being interpreted

//    Llocals      the base pointer for accessing the locals array

//                 (lower-numbered locals have lower addresses)

//    Lmonitors    the base pointer for accessing active monitors

//    Lcache       a saved pointer to the method's constant pool cache

//

//

// When calling out to another method,

// G5_method is set to method to call, G5_inline_cache_klass may be set,

// parameters are put in O registers, and also extra parameters

// must be cleverly copied from the top of stack to the outgoing param area in the frame,

// All frames:

 public:

  enum {

    // normal return address is 2 words past PC

    pc_return_offset                             = 2 * BytesPerInstWord,

    // size of each block, in order of increasing address:

    register_save_words                          = 16,

    callee_aggregate_return_pointer_words        =  0,

    callee_register_argument_save_area_words     =  6,

    // memory_parameter_words                    = <arbitrary>,

    // offset of each block, in order of increasing address:

    // (note: callee_register_argument_save_area_words == Assembler::n_register_parameters)

    register_save_words_sp_offset                = 0,

    callee_aggregate_return_pointer_sp_offset    = register_save_words_sp_offset + register_save_words,

    callee_register_argument_save_area_sp_offset = callee_aggregate_return_pointer_sp_offset + callee_aggregate_return_pointer_words,

    memory_parameter_word_sp_offset              = callee_register_argument_save_area_sp_offset + callee_register_argument_save_area_words,

    varargs_offset                               = memory_parameter_word_sp_offset

  };

 private:

  intptr_t*  _younger_sp;                 // optional SP of callee (used to locate O7)

  int        _sp_adjustment_by_callee;   // adjustment in words to SP by callee for making locals contiguous

  // Note:  On SPARC, unlike Intel, the saved PC for a stack frame

  // is stored at a __variable__ distance from that frame's SP.

  // (In fact, it may be in the register save area of the callee frame,

  // but that fact need not bother us.)  Thus, we must store the

  // address of that saved PC explicitly.  On the other hand, SPARC

  // stores the FP for a frame at a fixed offset from the frame's SP,

  // so there is no need for a separate "frame::_fp" field.

 public:

  // Accessors

  intptr_t* younger_sp() const {

    assert(_younger_sp != NULL, "frame must possess a younger_sp");

    return _younger_sp;

  }

  int callee_sp_adjustment() const { return _sp_adjustment_by_callee; }

  void set_sp_adjustment_by_callee(int number_of_words) { _sp_adjustment_by_callee = number_of_words; }

  // Constructors

  // This constructor relies on the fact that the creator of a frame

  // has flushed register windows which the frame will refer to, and

  // that those register windows will not be reloaded until the frame is

  // done reading and writing the stack.  Moreover, if the "younger_sp"

  // argument points into the register save area of the next younger

  // frame (though it need not), the register window for that next

  // younger frame must also stay flushed.  (The caller is responsible

  // for ensuring this.)

  frame(intptr_t* sp, intptr_t* younger_sp, bool younger_frame_adjusted_stack = false);

  // make a deficient frame which doesn't know where its PC is:

  enum unpatchable_t { unpatchable };

  frame(intptr_t* sp, unpatchable_t, address pc = NULL, CodeBlob* cb = NULL);

  void init(intptr_t* sp, address pc, CodeBlob* cb);

  // Walk from sp outward looking for old_sp, and return old_sp's predecessor

  // (i.e. return the sp from the frame where old_sp is the fp).

  // Register windows are assumed to be flushed for the stack in question.

  static intptr_t* next_younger_sp_or_null(intptr_t* old_sp, intptr_t* sp);

  // Return true if sp is a younger sp in the stack described by valid_sp.

  static bool is_valid_stack_pointer(intptr_t* valid_sp, intptr_t* sp);

 public:

  // accessors for the instance variables

  intptr_t*   fp() const { return (intptr_t*) ((intptr_t)(sp()[FP->sp_offset_in_saved_window()]) + STACK_BIAS ); }

  // All frames

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

  intptr_t*  sp_addr_at(int index) const   { return &sp()[index];    }

  intptr_t   fp_at(     int index) const   { return *fp_addr_at(index); }

  intptr_t   sp_at(     int index) const   { return *sp_addr_at(index); }

 private:

  inline address* I7_addr() const;

  inline address* O7_addr() const;

  inline address* I0_addr() const;

  inline address* O0_addr() const;

  intptr_t*  younger_sp_addr_at(int index) const   { return &younger_sp()[index];    }

 public:

  // access to SPARC arguments and argument registers

  // Assumes reg is an in/local register

  intptr_t*     register_addr(Register reg) const {

    return sp_addr_at(reg->sp_offset_in_saved_window());

  }

  // Assumes reg is an out register

  intptr_t*     out_register_addr(Register reg) const {

    return younger_sp_addr_at(reg->after_save()->sp_offset_in_saved_window());

  }

  // Interpreter frames

 public:

  // Asm interpreter

  enum interpreter_frame_vm_locals {

       // 2 words, also used to save float regs across  calls to C

       interpreter_frame_d_scratch_fp_offset          = -2,

       interpreter_frame_l_scratch_fp_offset          = -4,

       interpreter_frame_mirror_offset                = -5, // keep interpreted method alive

       interpreter_frame_oop_temp_offset              = -6, // for native calls only

       interpreter_frame_vm_locals_fp_offset          = -6, // should be same as above, and should be zero mod 8

       interpreter_frame_vm_local_words = -interpreter_frame_vm_locals_fp_offset,

       // interpreter frame set-up needs to save 2 extra words in outgoing param area

       // for class and jnienv arguments for native stubs (see nativeStubGen_sparc.cpp_

       interpreter_frame_extra_outgoing_argument_words = 2

  };

  enum compiler_frame_fixed_locals {

       compiler_frame_vm_locals_fp_offset          = -2

  };

 private:

  ConstantPoolCache** interpreter_frame_cpoolcache_addr() const;

  // where Lmonitors is saved:

  inline BasicObjectLock** interpreter_frame_monitors_addr() const;

  inline intptr_t** interpreter_frame_esp_addr() const;

  inline void interpreter_frame_set_tos_address(intptr_t* x);

  // monitors:

  // next two fns read and write Lmonitors value,

 private:

  BasicObjectLock* interpreter_frame_monitors() const;

  void interpreter_frame_set_monitors(BasicObjectLock* monitors);

 public:

  static jint interpreter_frame_expression_stack_direction() { return -1; }