ocaml/byterun/memory.h

/***********************************************************************/
/*                                                                     */
/*                                OCaml                                */
/*                                                                     */
/*             Damien Doligez, projet Para, INRIA Rocquencourt         */
/*                                                                     */
/*  Copyright 1996 Institut National de Recherche en Informatique et   */
/*  en Automatique.  All rights reserved.  This file is distributed    */
/*  under the terms of the GNU Library General Public License, with    */
/*  the special exception on linking described in file ../LICENSE.     */
/*                                                                     */
/***********************************************************************/

/* $Id$ */

/* Allocation macros and functions */

#ifndef CAML_MEMORY_H
#define CAML_MEMORY_H

#ifndef CAML_NAME_SPACE
#include "compatibility.h"
#endif
#include "config.h"
/* <private> */
#include "gc.h"
#include "major_gc.h"
#include "minor_gc.h"
/* </private> */
#include "misc.h"
#include "mlvalues.h"

#ifdef __cplusplus
extern "C" {
#endif


CAMLextern value caml_alloc_shr (mlsize_t, tag_t);
CAMLextern void caml_adjust_gc_speed (mlsize_t, mlsize_t);
CAMLextern void caml_alloc_dependent_memory (mlsize_t);
CAMLextern void caml_free_dependent_memory (mlsize_t);
CAMLextern void caml_modify (value *, value);
CAMLextern void caml_initialize (value *, value);
CAMLextern value caml_check_urgent_gc (value);
CAMLextern void * caml_stat_alloc (asize_t);              /* Size in bytes. */
CAMLextern void caml_stat_free (void *);
CAMLextern void * caml_stat_resize (void *, asize_t);     /* Size in bytes. */
char *caml_alloc_for_heap (asize_t request);   /* Size in bytes. */
void caml_free_for_heap (char *mem);
int caml_add_to_heap (char *mem);
color_t caml_allocation_color (void *hp);

/* void caml_shrink_heap (char *);        Only used in compact.c */

/* <private> */

#define Not_in_heap 0
#define In_heap 1
#define In_young 2
#define In_static_data 4
#define In_code_area 8

#ifdef ARCH_SIXTYFOUR

/* 64 bits: Represent page table as a sparse hash table */
int caml_page_table_lookup(void * addr);
#define Classify_addr(a) (caml_page_table_lookup((void *)(a)))

#else

/* 32 bits: Represent page table as a 2-level array */
#define Pagetable2_log 11
#define Pagetable2_size (1 << Pagetable2_log)
#define Pagetable1_log (Page_log + Pagetable2_log)
#define Pagetable1_size (1 << (32 - Pagetable1_log))
CAMLextern unsigned char * caml_page_table[Pagetable1_size];

#define Pagetable_index1(a) (((uintnat)(a)) >> Pagetable1_log)
#define Pagetable_index2(a) \
  ((((uintnat)(a)) >> Page_log) & (Pagetable2_size - 1))
#define Classify_addr(a) \
  caml_page_table[Pagetable_index1(a)][Pagetable_index2(a)]

#endif

#define Is_in_value_area(a) \
  (Classify_addr(a) & (In_heap | In_young | In_static_data))
#define Is_in_heap(a) (Classify_addr(a) & In_heap)
#define Is_in_heap_or_young(a) (Classify_addr(a) & (In_heap | In_young))

int caml_page_table_add(int kind, void * start, void * end);
int caml_page_table_remove(int kind, void * start, void * end);
int caml_page_table_initialize(mlsize_t bytesize);

#ifdef DEBUG
#define DEBUG_clear(result, wosize) do{ \
  uintnat caml__DEBUG_i; \
  for (caml__DEBUG_i = 0; caml__DEBUG_i < (wosize); ++ caml__DEBUG_i){ \
    Field ((result), caml__DEBUG_i) = Debug_uninit_minor; \
  } \
}while(0)
#else
#define DEBUG_clear(result, wosize)
#endif

#define Alloc_small(result, wosize, tag) do{    CAMLassert ((wosize) >= 1); \
                                          CAMLassert ((tag_t) (tag) < 256); \
                                 CAMLassert ((wosize) <= Max_young_wosize); \
  caml_young_ptr -= Bhsize_wosize (wosize);                                 \
  if (caml_young_ptr < caml_young_start){                                   \
    caml_young_ptr += Bhsize_wosize (wosize);                               \
    Setup_for_gc;                                                           \
    caml_minor_collection ();                                               \
    Restore_after_gc;                                                       \
    caml_young_ptr -= Bhsize_wosize (wosize);                               \
  }                                                                         \
  Hd_hp (caml_young_ptr) = Make_header ((wosize), (tag), Caml_black);       \
  (result) = Val_hp (caml_young_ptr);                                       \
  DEBUG_clear ((result), (wosize));                                         \
}while(0)

/* You must use [Modify] to change a field of an existing shared block,
   unless you are sure the value being overwritten is not a shared block and
   the value being written is not a young block. */
/* [Modify] never calls the GC. */
/* [Modify] can also be used to do assignment on data structures that are
   not in the (major) heap.  In this case, it is a bit slower than
   simple assignment.
   In particular, you can use [Modify] when you don't know whether the
   block being changed is in the minor heap or the major heap.
*/

#define Modify(fp, val) do{                                                 \
  value _old_ = *(fp);                                                      \
  *(fp) = (val);                                                            \
  if (Is_in_heap (fp)){                                                     \
    if (caml_gc_phase == Phase_mark) caml_darken (_old_, NULL);             \
    if (Is_block (val) && Is_young (val)                                    \
        && ! (Is_block (_old_) && Is_young (_old_))){                       \
      if (caml_ref_table.ptr >= caml_ref_table.limit){                      \
        CAMLassert (caml_ref_table.ptr == caml_ref_table.limit);            \
        caml_realloc_ref_table (&caml_ref_table);                           \
      }                                                                     \
      *caml_ref_table.ptr++ = (fp);                                         \
    }                                                                       \
  }                                                                         \
}while(0)

/* </private> */

struct caml__roots_block {
  struct caml__roots_block *next;
  intnat ntables;
  intnat nitems;
  value *tables [5];
};

CAMLextern struct caml__roots_block *caml_local_roots;  /* defined in roots.c */

/* The following macros are used to declare C local variables and
   function parameters of type [value].

   The function body must start with one of the [CAMLparam] macros.
   If the function has no parameter of type [value], use [CAMLparam0].
   If the function has 1 to 5 [value] parameters, use the corresponding
   [CAMLparam] with the parameters as arguments.
   If the function has more than 5 [value] parameters, use [CAMLparam5]
   for the first 5 parameters, and one or more calls to the [CAMLxparam]
   macros for the others.
   If the function takes an array of [value]s as argument, use
   [CAMLparamN] to declare it (or [CAMLxparamN] if you already have a
   call to [CAMLparam] for some other arguments).

   If you need local variables of type [value], declare them with one
   or more calls to the [CAMLlocal] macros at the beginning of the
   function. Use [CAMLlocalN] (at the beginning of the function) to
   declare an array of [value]s.

   Your function may raise an exception or return a [value] with the
   [CAMLreturn] macro.  Its argument is simply the [value] returned by
   your function.  Do NOT directly return a [value] with the [return]
   keyword.  If your function returns void, use [CAMLreturn0].

   All the identifiers beginning with "caml__" are reserved by Caml.
   Do not use them for anything (local or global variables, struct or
   union tags, macros, etc.)
*/

#define CAMLparam0() \
  struct caml__roots_block *caml__frame = caml_local_roots

#define CAMLparam1(x) \
  CAMLparam0 (); \
  CAMLxparam1 (x)

#define CAMLparam2(x, y) \
  CAMLparam0 (); \
  CAMLxparam2 (x, y)

#define CAMLparam3(x, y, z) \
  CAMLparam0 (); \
  CAMLxparam3 (x, y, z)

#define CAMLparam4(x, y, z, t) \
  CAMLparam0 (); \
  CAMLxparam4 (x, y, z, t)

#define CAMLparam5(x, y, z, t, u) \
  CAMLparam0 (); \
  CAMLxparam5 (x, y, z, t, u)

#define CAMLparamN(x, size) \
  CAMLparam0 (); \
  CAMLxparamN (x, (size))


#if defined (__GNUC__) && (__GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ > 7))
  #define CAMLunused __attribute__ ((unused))
#else
  #define CAMLunused
#endif

#define CAMLxparam1(x) \
  struct caml__roots_block caml__roots_##x; \
  CAMLunused int caml__dummy_##x = ( \
    (caml__roots_##x.next = caml_local_roots), \
    (caml_local_roots = &caml__roots_##x), \
    (caml__roots_##x.nitems = 1), \
    (caml__roots_##x.ntables = 1), \
    (caml__roots_##x.tables [0] = &x), \
    0)

#define CAMLxparam2(x, y) \
  struct caml__roots_block caml__roots_##x; \
  CAMLunused int caml__dummy_##x = ( \
    (caml__roots_##x.next = caml_local_roots), \
    (caml_local_roots = &caml__roots_##x), \
    (caml__roots_##x.nitems = 1), \
    (caml__roots_##x.ntables = 2), \
    (caml__roots_##x.tables [0] = &x), \
    (caml__roots_##x.tables [1] = &y), \
    0)

#define CAMLxparam3(x, y, z) \
  struct caml__roots_block caml__roots_##x; \
  CAMLunused int caml__dummy_##x = ( \
    (caml__roots_##x.next = caml_local_roots), \
    (caml_local_roots = &caml__roots_##x), \
    (caml__roots_##x.nitems = 1), \
    (caml__roots_##x.ntables = 3), \
    (caml__roots_##x.tables [0] = &x), \
    (caml__roots_##x.tables [1] = &y), \
    (caml__roots_##x.tables [2] = &z), \
    0)

#define CAMLxparam4(x, y, z, t) \
  struct caml__roots_block caml__roots_##x; \
  CAMLunused int caml__dummy_##x = ( \
    (caml__roots_##x.next = caml_local_roots), \
    (caml_local_roots = &caml__roots_##x), \
    (caml__roots_##x.nitems = 1), \
    (caml__roots_##x.ntables = 4), \
    (caml__roots_##x.tables [0] = &x), \
    (caml__roots_##x.tables [1] = &y), \
    (caml__roots_##x.tables [2] = &z), \
    (caml__roots_##x.tables [3] = &t), \
    0)

#define CAMLxparam5(x, y, z, t, u) \
  struct caml__roots_block caml__roots_##x; \
  CAMLunused int caml__dummy_##x = ( \
    (caml__roots_##x.next = caml_local_roots), \
    (caml_local_roots = &caml__roots_##x), \
    (caml__roots_##x.nitems = 1), \
    (caml__roots_##x.ntables = 5), \
    (caml__roots_##x.tables [0] = &x), \
    (caml__roots_##x.tables [1] = &y), \
    (caml__roots_##x.tables [2] = &z), \
    (caml__roots_##x.tables [3] = &t), \
    (caml__roots_##x.tables [4] = &u), \
    0)

#define CAMLxparamN(x, size) \
  struct caml__roots_block caml__roots_##x; \
  CAMLunused int caml__dummy_##x = ( \
    (caml__roots_##x.next = caml_local_roots), \
    (caml_local_roots = &caml__roots_##x), \
    (caml__roots_##x.nitems = (size)), \
    (caml__roots_##x.ntables = 1), \
    (caml__roots_##x.tables[0] = &(x[0])), \
    0)

#define CAMLlocal1(x) \
  value x = 0; \
  CAMLxparam1 (x)

#define CAMLlocal2(x, y) \
  value x = 0, y = 0; \
  CAMLxparam2 (x, y)

#define CAMLlocal3(x, y, z) \
  value x = 0, y = 0, z = 0; \
  CAMLxparam3 (x, y, z)

#define CAMLlocal4(x, y, z, t) \
  value x = 0, y = 0, z = 0, t = 0; \
  CAMLxparam4 (x, y, z, t)

#define CAMLlocal5(x, y, z, t, u) \
  value x = 0, y = 0, z = 0, t = 0, u = 0; \
  CAMLxparam5 (x, y, z, t, u)

#define CAMLlocalN(x, size) \
  value x [(size)] = { 0, /* 0, 0, ... */ }; \
  CAMLxparamN (x, (size))


#define CAMLreturn0 do{ \
  caml_local_roots = caml__frame; \
  return; \
}while (0)

#define CAMLreturnT(type, result) do{ \
  type caml__temp_result = (result); \
  caml_local_roots = caml__frame; \
  return (caml__temp_result); \
}while(0)

#define CAMLreturn(result) CAMLreturnT(value, result)

#define CAMLnoreturn ((void) caml__frame)


/* convenience macro */
#define Store_field(block, offset, val) do{ \
  mlsize_t caml__temp_offset = (offset); \
  value caml__temp_val = (val); \
  caml_modify (&Field ((block), caml__temp_offset), caml__temp_val); \
}while(0)

/*
   NOTE: [Begin_roots] and [End_roots] are superseded by [CAMLparam]*,
   [CAMLxparam]*, [CAMLlocal]*, [CAMLreturn].

   [Begin_roots] and [End_roots] are used for C variables that are GC roots.
   It must contain all values in C local variables and function parameters
   at the time the minor GC is called.
   Usage:
   After initialising your local variables to legal Caml values, but before
   calling allocation functions, insert [Begin_roots_n(v1, ... vn)], where
   v1 ... vn are your variables of type [value] that you want to be updated
   across allocations.
   At the end, insert [End_roots()].

   Note that [Begin_roots] opens a new block, and [End_roots] closes it.
   Thus they must occur in matching pairs at the same brace nesting level.

   You can use [Val_unit] as a dummy initial value for your variables.
*/

#define Begin_root Begin_roots1

#define Begin_roots1(r0) { \
  struct caml__roots_block caml__roots_block; \
  caml__roots_block.next = caml_local_roots; \
  caml_local_roots = &caml__roots_block; \
  caml__roots_block.nitems = 1; \
  caml__roots_block.ntables = 1; \
  caml__roots_block.tables[0] = &(r0);

#define Begin_roots2(r0, r1) { \
  struct caml__roots_block caml__roots_block; \
  caml__roots_block.next = caml_local_roots; \
  caml_local_roots = &caml__roots_block; \
  caml__roots_block.nitems = 1; \
  caml__roots_block.ntables = 2; \
  caml__roots_block.tables[0] = &(r0); \
  caml__roots_block.tables[1] = &(r1);

#define Begin_roots3(r0, r1, r2) { \
  struct caml__roots_block caml__roots_block; \
  caml__roots_block.next = caml_local_roots; \
  caml_local_roots = &caml__roots_block; \
  caml__roots_block.nitems = 1; \
  caml__roots_block.ntables = 3; \
  caml__roots_block.tables[0] = &(r0); \
  caml__roots_block.tables[1] = &(r1); \
  caml__roots_block.tables[2] = &(r2);

#define Begin_roots4(r0, r1, r2, r3) { \
  struct caml__roots_block caml__roots_block; \
  caml__roots_block.next = caml_local_roots; \
  caml_local_roots = &caml__roots_block; \
  caml__roots_block.nitems = 1; \
  caml__roots_block.ntables = 4; \
  caml__roots_block.tables[0] = &(r0); \
  caml__roots_block.tables[1] = &(r1); \
  caml__roots_block.tables[2] = &(r2); \
  caml__roots_block.tables[3] = &(r3);

#define Begin_roots5(r0, r1, r2, r3, r4) { \
  struct caml__roots_block caml__roots_block; \
  caml__roots_block.next = caml_local_roots; \
  caml_local_roots = &caml__roots_block; \
  caml__roots_block.nitems = 1; \
  caml__roots_block.ntables = 5; \
  caml__roots_block.tables[0] = &(r0); \
  caml__roots_block.tables[1] = &(r1); \
  caml__roots_block.tables[2] = &(r2); \
  caml__roots_block.tables[3] = &(r3); \
  caml__roots_block.tables[4] = &(r4);

#define Begin_roots_block(table, size) { \
  struct caml__roots_block caml__roots_block; \
  caml__roots_block.next = caml_local_roots; \
  caml_local_roots = &caml__roots_block; \
  caml__roots_block.nitems = (size); \
  caml__roots_block.ntables = 1; \
  caml__roots_block.tables[0] = (table);

#define End_roots() caml_local_roots = caml__roots_block.next; }


/* [caml_register_global_root] registers a global C variable as a memory root
   for the duration of the program, or until [caml_remove_global_root] is
   called. */

CAMLextern void caml_register_global_root (value *);

/* [caml_remove_global_root] removes a memory root registered on a global C
   variable with [caml_register_global_root]. */

CAMLextern void caml_remove_global_root (value *);

/* [caml_register_generational_global_root] registers a global C
   variable as a memory root for the duration of the program, or until
   [caml_remove_generational_global_root] is called.
   The program guarantees that the value contained in this variable
   will not be assigned directly.  If the program needs to change
   the value of this variable, it must do so by calling
   [caml_modify_generational_global_root].  The [value *] pointer
   passed to [caml_register_generational_global_root] must contain
   a valid Caml value before the call.
   In return for these constraints, scanning of memory roots during
   minor collection is made more efficient. */

CAMLextern void caml_register_generational_global_root (value *);

/* [caml_remove_generational_global_root] removes a memory root
   registered on a global C variable with
   [caml_register_generational_global_root]. */

CAMLextern void caml_remove_generational_global_root (value *);

/* [caml_modify_generational_global_root(r, newval)]
   modifies the value contained in [r], storing [newval] inside.
   In other words, the assignment [*r = newval] is performed,
   but in a way that is compatible with the optimized scanning of
   generational global roots.  [r] must be a global memory root
   previously registered with [caml_register_generational_global_root]. */

CAMLextern void caml_modify_generational_global_root(value *r, value newval);

#ifdef __cplusplus
}
#endif

#endif /* CAML_MEMORY_H */