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rosella/gc.h

489 lines
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C
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#ifndef GC_H_6b8a27c99f2eb5eb5437e045fa4af1c3
#define GC_H_6b8a27c99f2eb5eb5437e045fa4af1c3
#include <assert.h>
#include <inttypes.h>
#include <stdbool.h>
#include <stdio.h>
#include <time.h>
/*
** Macro Definitions
*/
/*
** nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn1 fixnum
**
** sssssssssssssssssssssssssss00000 special
** xxxxxxxxxxyyyyyyyyyyyyyyyyy00010 object_blocks[x].objects[y].box
** xxxxxxxxxxyyyyyyyyyyyyyyyyy00100 object_blocks[x].objects[y].weak_box
** xxxxxxxxxxyyyyyyyyyyyyyyyyy00110 object_blocks[x].objects[y].pair
** xxxxxxxxxxyyyyyyyyyyyyyyyyy01000 object_blocks[x].objects[y].fpnum
** xxxxxxxxxxyyyyyyyyyyyyyyyyy01010 object_blocks[x].objects[y].builtin_fn
** xxxxxxxxxxyyyyyyyyyyyyyyyyy01100 reserved
** xxxxxxxxxxyyyyyyyyyyyyyyyyy01110 reserved
**
** xxxxxxxxxxyyyyyyyyyyyyyyyyy10000 object_blocks[x].objects[y].vector
** xxxxxxxxxxyyyyyyyyyyyyyyyyy10010 object_blocks[x].objects[y].byte_string
** xxxxxxxxxxyyyyyyyyyyyyyyyyy10100 object_blocks[x].objects[y].structure
** xxxxxxxxxxyyyyyyyyyyyyyyyyy10110 object_blocks[x].objects[y].will
** xxxxxxxxxxyyyyyyyyyyyyyyyyy11000 reserved
** xxxxxxxxxxyyyyyyyyyyyyyyyyy11010 reserved
** xxxxxxxxxxyyyyyyyyyyyyyyyyy11100 reserved
** xxxxxxxxxxyyyyyyyyyyyyyyyyy11110 reserved
*/
#define FIXNUM_MIN (INT32_MIN/2)
#define FIXNUM_MAX (INT32_MAX/2)
#define OBJECT_BLOCK_MAX 0x3ff
#define OBJECT_INDEX_MAX 0x1ffff
#define OBJECT_TAG_MAX 0xf
#define OBJECT_TAG_FIXNUM -1
#define OBJECT_TAG_SPECIAL 0
#define OBJECT_TAG_BOX 1
#define OBJECT_TAG_WEAK_BOX 2
#define OBJECT_TAG_PAIR 3
#define OBJECT_TAG_FPNUM 4
#define OBJECT_TAG_BUILTIN_FN 5
/* 6 & 7 are reserved */
#define OBJECT_TAG_VECTOR 8
#define OBJECT_TAG_BYTE_STRING 9
#define OBJECT_TAG_STRUCT 10
#define OBJECT_TAG_WILL 11
/* 12-15 are reserved */
#define OBJECT(blk, idx, tag) \
((((value_t)(blk) & 0x3ff) << 22) | \
(((value_t)(idx) & 0x1ffff) << 5) | \
(((value_t)(tag) & 0xf) << 1))
#define OBJECT_BLOCK(value) ((int)(((value) >> 22) & 0x3ff))
#define OBJECT_INDEX(value) ((int)(((value) >> 5) & 0x1ffff))
#define OBJECT_TAG(value) ((int)(((value) >> 1) & 0xf))
#define SPECIAL_VALUE(n) ((value_t)(n) << 5)
#define SPECIAL_MAX ((value_t)(-1) << 5)
#define UNDEFINED SPECIAL_VALUE(0)
#define NIL SPECIAL_VALUE(1)
#define FALSE_VALUE SPECIAL_VALUE(2)
#define TRUE_VALUE SPECIAL_VALUE(3)
#define END_PROGRAM SPECIAL_VALUE(4)
#define CAR(x) (get_pair(x)->car)
#define CDR(x) (get_pair(x)->cdr)
#define CADR(x) CAR(CDR(x))
#define CDDR(x) CDR(CDR(x))
/* Ex: SLOT_VALUE(STRUCTURE, v, NAME) */
#define SLOT_VALUE(t,v,s) (get_struct(v)->slots[t ## _SLOT_ ## s])
#define _SLOT_VALUE(t,v,s) SLOT_VALUE(t,v,s)
#define STRUCTURE_SLOT_SUPER 0
#define STRUCTURE_SLOT_NSLOTS 1
#define STRUCTURE_SLOT_CALLABLE 2
#define STRUCTURE_SLOTS 3
/* Invoke this macro after updating any object with a new object reference. */
/* Write barriers are required for generational and incremental collectors. */
/* If unsure, invoke the macro; at most there will be a slight cost in performance. */
/* Failing to invoke the macro before the next GC pass can lead to incorrect behavior. */
#define WRITE_BARRIER(value) ((void)0)
/* Like assert(), but for things we want to check even in release builds. */
/* More informative than a simple "if (!x) abort();" statement. */
#define release_assert(expr) \
((expr) ? (void)0 : (void)_release_assert(#expr, __FILE__, __LINE__))
/* Evaluates to false, but with an expression that conveys what went wrong. */
#define NOTREACHED(msg) 0
/*
** Type Definitions
*/
/* Primitive types */
typedef uint32_t value_t;
typedef int32_t fixnum_t;
typedef double fpnum_t;
/* Builtins replace the normal run_byte_code() and perform_tail_call() steps.
* The argv, k, and ctx inputs can be found in the state fields, and should be
* updated as necessary (particularly argv) before the builtin returns. The
* 'lambda' field will refer to the builtin itself, and in1-in3 are all free. */
struct interp_state;
typedef void builtin_fn_t(struct interp_state *state);
typedef struct box
{
value_t value;
} box_t;
typedef struct weak_box
{
value_t value;
value_t next;
} weak_box_t;
typedef struct pair
{
value_t car;
value_t cdr;
} pair_t;
typedef struct vector
{
bool immutable;
size_t nelements;
value_t elements[0];
} vector_t;
typedef struct byte_string
{
bool immutable;
size_t nbytes;
uint8_t bytes[0];
} byte_string_t;
typedef struct structure
{
bool immutable;
size_t nslots;
value_t type;
value_t slots[0];
} struct_t;
typedef struct will
{
value_t value;
value_t finalizer;
value_t next;
} will_t;
typedef union object
{
/* free list */
value_t next;
/* direct values */
box_t box;
weak_box_t weak_box;
pair_t pair;
fpnum_t fpnum;
builtin_fn_t *builtin_fn;
/* indirect values */
vector_t *vector;
byte_string_t *byte_string;
struct_t *structure;
will_t *will;
} object_t;
typedef struct object_block
{
object_t *objects;
uint32_t *flag_bits;
} object_block_t;
typedef struct gc_root
{
value_t value;
struct gc_root *prev;
struct gc_root *next;
} gc_root_t;
/* uint64_t isn't present everywhere */
typedef unsigned long long nsec_t;
typedef unsigned long long llsize_t;
typedef struct gc_stats
{
int passes;
nsec_t total_ns;
nsec_t peak_ns;
llsize_t total_freed;
llsize_t peak_allocated;
} gc_stats_t;
/*
** Object Declarations
*/
extern const char *const object_tag_names[16];
extern object_block_t object_blocks[OBJECT_BLOCK_MAX + 1];
extern gc_stats_t gc_stats;
/*
** Function Declarations
*/
static inline bool get_boolean(value_t v);
static inline fixnum_t get_fixnum(value_t v);
static inline fpnum_t get_float(value_t v);
static inline builtin_fn_t *get_builtin_fn(value_t v);
static inline box_t *get_box(value_t v);
static inline weak_box_t *get_weak_box(value_t v);
static inline pair_t *get_pair(value_t v);
static inline vector_t *get_vector(value_t v);
static inline byte_string_t *get_byte_string(value_t v);
static inline struct_t *get_struct(value_t v);
/* wills are deliberately omitted from the public interface */
static inline value_t make_boolean(bool value);
static inline value_t make_fixnum(fixnum_t value);
value_t make_float(fpnum_t value);
value_t make_builtin_fn(builtin_fn_t *fn);
value_t make_box(value_t initial_value);
value_t make_weak_box(value_t value);
value_t make_pair(value_t car, value_t cdr);
value_t make_vector(size_t nelements, value_t init);
value_t make_byte_string(size_t nbytes, int init);
value_t make_struct(value_t type);
/* wills are deliberately omitted from the public interface */
/* Returns a byte string w/ bytes from 's' (excl. terminating NUL). */
value_t string_to_value(const char *s);
/* Returns a new C string which must be free()'d by caller. */
char *value_to_string(value_t v);
/* Like strcmp(), but for byte strings. */
int byte_strcmp(value_t s1, value_t s2);
/* Return the structure instance at the root of the structure type hierarchy. */
value_t get_structure_type(void);
/* Instantiates a structure type. Result is immutable. */
value_t make_struct_type(value_t super, fixnum_t nslots, value_t callable);
/* True if 'value' is (1) a structure, and (2) an instance of 'type'. */
bool struct_is_a(value_t value, value_t type);
/* Finalizers are register-and-forget; there should be no external references to wills. */
void register_finalizer(value_t value, value_t finalizer);
bool are_finalizers_pending(void);
/* If *value == #f on return there are no more finalizers. */
void get_next_finalizer(value_t *value, value_t *finalizer);
void register_gc_root(gc_root_t *root, value_t v);
void unregister_gc_root(gc_root_t *root);
void gc_init(void);
void clear_gc_stats(void);
void collect_garbage(void);
bool set_gc_enabled(bool enable);
void fprint_value(FILE *f, value_t v);
void fprint_gc_stats(FILE *f);
/* Implements the release_assert() macro */
void _release_assert(const char *str, const char *file, int line) __attribute__((noreturn));
/* To be provided by the main application */
void out_of_memory(void);
/*
** Static Function Definitions
*/
static inline bool is_valid_fixnum(fixnum_t n)
{
return (FIXNUM_MIN <= n) && (n <= FIXNUM_MAX);
}
static inline bool is_nil(value_t v)
{
return v == NIL;
}
static inline bool is_undefined(value_t v)
{
return v == UNDEFINED;
}
static inline bool is_boolean(value_t v)
{
return (v == FALSE_VALUE) || (v == TRUE_VALUE);
}
static inline bool is_fixnum(value_t value)
{
return (value & 1) != 0;
}
static inline bool is_object_type(value_t value, int tag)
{
if (tag == OBJECT_TAG_FIXNUM)
return is_fixnum(value);
else if ((tag < 0) || (tag > OBJECT_TAG_MAX))
return false;
else
return ((value & 0x1f) == ((value_t)tag << 1));
}
static inline bool is_special(value_t value)
{
return is_object_type(value, OBJECT_TAG_SPECIAL);
}
static inline bool is_object(value_t value)
{
return !is_fixnum(value) && !is_special(value);
}
static inline bool is_box(value_t value)
{
return is_object_type(value, OBJECT_TAG_BOX);
}
static inline bool is_weak_box(value_t value)
{
return is_object_type(value, OBJECT_TAG_WEAK_BOX);
}
static inline bool is_pair(value_t value)
{
return is_object_type(value, OBJECT_TAG_PAIR);
}
static inline bool is_list(value_t value)
{
return is_nil(value) || is_pair(value);
}
static inline bool is_float(value_t value)
{
return is_object_type(value, OBJECT_TAG_FPNUM);
}
static inline bool is_builtin_fn(value_t value)
{
return is_object_type(value, OBJECT_TAG_BUILTIN_FN);
}
static inline bool is_vector(value_t value)
{
return is_object_type(value, OBJECT_TAG_VECTOR);
}
static inline bool is_byte_string(value_t value)
{
return is_object_type(value, OBJECT_TAG_BYTE_STRING);
}
static inline bool is_struct(value_t value)
{
return is_object_type(value, OBJECT_TAG_STRUCT);
}
static inline int get_object_type(value_t value)
{
if (is_fixnum(value))
return OBJECT_TAG_FIXNUM;
else
return OBJECT_TAG(value);
}
static inline bool get_boolean(value_t v)
{
return v != FALSE_VALUE;
}
static inline int32_t get_fixnum(value_t value)
{
return (int32_t)value >> 1;
}
static inline object_t *_get_object(value_t value)
{
release_assert(is_object(value));
return &object_blocks[OBJECT_BLOCK(value)].objects[OBJECT_INDEX(value)];
}
static inline object_t *_get_typed_object(value_t value, int tag)
{
if (!is_object_type(value, tag))
{
if (is_fixnum(value))
{
fprintf(stderr, "ERROR: Expected %s, found fixnum.\n", object_tag_names[tag]);
}
else
{
fprintf(stderr, "ERROR: Expected %s, found %s.\n",
object_tag_names[tag], object_tag_names[OBJECT_TAG(value)]);
}
release_assert(is_object_type(value, tag));
}
return &object_blocks[OBJECT_BLOCK(value)].objects[OBJECT_INDEX(value)];
}
static inline box_t *get_box(value_t value)
{
return &_get_typed_object(value, OBJECT_TAG_BOX)->box;
}
static inline weak_box_t *get_weak_box(value_t value)
{
return &_get_typed_object(value, OBJECT_TAG_WEAK_BOX)->weak_box;
}
static inline pair_t *get_pair(value_t value)
{
return &_get_typed_object(value, OBJECT_TAG_PAIR)->pair;
}
static inline fpnum_t get_float(value_t value)
{
return _get_typed_object(value, OBJECT_TAG_FPNUM)->fpnum;
}
static inline builtin_fn_t *get_builtin_fn(value_t value)
{
return _get_typed_object(value, OBJECT_TAG_BUILTIN_FN)->builtin_fn;
}
static inline vector_t *get_vector(value_t value)
{
return _get_typed_object(value, OBJECT_TAG_VECTOR)->vector;
}
static inline byte_string_t *get_byte_string(value_t value)
{
return _get_typed_object(value, OBJECT_TAG_BYTE_STRING)->byte_string;
}
static inline struct_t *get_struct(value_t value)
{
return _get_typed_object(value, OBJECT_TAG_STRUCT)->structure;
}
static inline value_t make_boolean(bool b)
{
return b ? TRUE_VALUE : FALSE_VALUE;
}
static inline value_t make_fixnum(int32_t n)
{
//release_assert(is_valid_fixnum(n));
return (value_t)((n << 1) | 1);
}
static inline void print_value(value_t v)
{
fprint_value(stdout, v);
}
static inline void print_gc_stats(void)
{
fprint_gc_stats(stderr);
}
#endif
/* vim:set sw=2 expandtab: */
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