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BCHPUR.C
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1992-06-03
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/* -*-C-*-
$Header: /scheme/src/microcode/RCS/bchpur.c,v 9.58 1992/06/03 21:54:53 jinx Exp $
Copyright (c) 1987-1992 Massachusetts Institute of Technology
This material was developed by the Scheme project at the Massachusetts
Institute of Technology, Department of Electrical Engineering and
Computer Science. Permission to copy this software, to redistribute
it, and to use it for any purpose is granted, subject to the following
restrictions and understandings.
1. Any copy made of this software must include this copyright notice
in full.
2. Users of this software agree to make their best efforts (a) to
return to the MIT Scheme project any improvements or extensions that
they make, so that these may be included in future releases; and (b)
to inform MIT of noteworthy uses of this software.
3. All materials developed as a consequence of the use of this
software shall duly acknowledge such use, in accordance with the usual
standards of acknowledging credit in academic research.
4. MIT has made no warrantee or representation that the operation of
this software will be error-free, and MIT is under no obligation to
provide any services, by way of maintenance, update, or otherwise.
5. In conjunction with products arising from the use of this material,
there shall be no use of the name of the Massachusetts Institute of
Technology nor of any adaptation thereof in any advertising,
promotional, or sales literature without prior written consent from
MIT in each case. */
/*
* This file contains the code for primitives dealing with pure
* and constant space. Garbage collection to disk version.
*
* Poorly implemented: If there is not enough space, instead of
* undoing the changes, it crashes.
* It should be changed to do the job in two passes like the
* "normal" version.
*/
#include "scheme.h"
#include "prims.h"
#include "bchgcc.h"
#include "zones.h"
/* Purify modes */
#define NORMAL_GC 0
#define PURE_COPY 1
#define CONSTANT_COPY 2
/* Some utility macros. */
#define relocate_indirect_setup() \
{ \
Old = OBJECT_ADDRESS (Temp); \
if (Old >= Low_Constant) \
continue; \
if (OBJECT_TYPE (*Old) == TC_BROKEN_HEART) \
{ \
continue; \
} \
New_Address = (MAKE_BROKEN_HEART (To_Address)); \
}
#define relocate_indirect_end() \
{ \
*OBJECT_ADDRESS (Temp) = New_Address; \
continue; \
}
/* A modified copy of GCLoop. */
static SCHEME_OBJECT *
DEFUN (purifyloop, (Scan, To_ptr, To_Address_ptr, purify_mode),
fast SCHEME_OBJECT *Scan AND
SCHEME_OBJECT **To_ptr AND
SCHEME_OBJECT **To_Address_ptr AND
int purify_mode)
{
fast SCHEME_OBJECT *To, *Old, Temp, *Low_Constant, *To_Address, New_Address;
To = *To_ptr;
To_Address = *To_Address_ptr;
Low_Constant = Constant_Space;
for ( ; Scan != To; Scan++)
{
Temp = *Scan;
Switch_by_GC_Type (Temp)
{
case TC_BROKEN_HEART:
if (Temp != (MAKE_POINTER_OBJECT (TC_BROKEN_HEART, Scan)))
{
sprintf (gc_death_message_buffer,
"purifyloop: broken heart (0x%lx) in scan",
Temp);
gc_death (TERM_BROKEN_HEART,
gc_death_message_buffer,
Scan, To);
/*NOTREACHED*/
}
if (Scan != scan_buffer_top)
goto end_purifyloop;
/* The -1 is here because of the Scan++ in the for header. */
Scan = ((dump_and_reload_scan_buffer (0, NULL)) - 1);
continue;
case TC_MANIFEST_NM_VECTOR:
case TC_MANIFEST_SPECIAL_NM_VECTOR:
/* Check whether this bumps over current buffer,
and if so we need a new bufferfull. */
Scan += (OBJECT_DATUM (Temp));
if (Scan < scan_buffer_top)
{
break;
}
else
{
unsigned long overflow;
/* The + & -1 are here because of the Scan++ in the for header. */
overflow = ((Scan - scan_buffer_top) + 1);
Scan = ((dump_and_reload_scan_buffer
((overflow >> gc_buffer_shift), NULL)
+ (overflow & gc_buffer_mask)) - 1);
break;
}
case_compiled_entry_point:
if (purify_mode == PURE_COPY)
break;
relocate_compiled_entry (false);
*Scan = Temp;
break;
case TC_LINKAGE_SECTION:
{
if (purify_mode == PURE_COPY)
{
gc_death (TERM_COMPILER_DEATH,
"purifyloop: linkage section in pure area",
Scan, To);
/*NOTREACHED*/
}
switch (READ_LINKAGE_KIND (Temp))
{
case REFERENCE_LINKAGE_KIND:
case ASSIGNMENT_LINKAGE_KIND:
{
/* count typeless pointers to quads follow. */
fast long count;
long max_count, max_here;
Scan++;
max_here = (scan_buffer_top - Scan);
max_count = (READ_CACHE_LINKAGE_COUNT (Temp));
while (max_count != 0)
{
count = ((max_count > max_here) ? max_here : max_count);
max_count -= count;
for ( ; --count >= 0; Scan += 1)
{
Temp = *Scan;
relocate_typeless_pointer (copy_quadruple(), 4);
}
if (max_count != 0)
{
/* We stopped because we needed to relocate too many. */
Scan = dump_and_reload_scan_buffer(0, NULL);
max_here = gc_buffer_size;
}
}
/* The + & -1 are here because of the Scan++ in the for header. */
Scan -= 1;
break;
}
case OPERATOR_LINKAGE_KIND:
case GLOBAL_OPERATOR_LINKAGE_KIND:
{
/* Operator linkage */
fast long count;
fast char *word_ptr, *next_ptr;
long overflow;
word_ptr = (FIRST_OPERATOR_LINKAGE_ENTRY (Scan));
if (word_ptr > ((char *) scan_buffer_top))
{
overflow = (word_ptr - ((char *) Scan));
extend_scan_buffer (word_ptr, To);
BCH_START_OPERATOR_RELOCATION (Scan);
word_ptr = (end_scan_buffer_extension (word_ptr));
Scan = ((SCHEME_OBJECT *) (word_ptr - overflow));
}
else
BCH_START_OPERATOR_RELOCATION (Scan);
count = (READ_OPERATOR_LINKAGE_COUNT (Temp));
overflow = ((END_OPERATOR_LINKAGE_AREA (Scan, count)) -
scan_buffer_top);
for (next_ptr = (NEXT_LINKAGE_OPERATOR_ENTRY (word_ptr));
(--count >= 0);
word_ptr = next_ptr,
next_ptr = (NEXT_LINKAGE_OPERATOR_ENTRY (word_ptr)))
{
if (next_ptr > ((char *) scan_buffer_top))
{
extend_scan_buffer (next_ptr, To);
relocate_linked_operator (false);
next_ptr = (end_scan_buffer_extension (next_ptr));
overflow -= gc_buffer_size;
}
else
relocate_linked_operator (false);
}
Scan = (scan_buffer_top + overflow);
BCH_END_OPERATOR_RELOCATION (Scan);
break;
}
default:
{
gc_death (TERM_EXIT,
"purify: Unknown compiler linkage kind.",
Scan, Free);
/*NOTREACHED*/
}
}
break;
}
case TC_MANIFEST_CLOSURE:
{
if (purify_mode == PURE_COPY)
{
gc_death (TERM_COMPILER_DEATH,
"purifyloop: manifest closure in pure area",
Scan, To);
/*NOTREACHED*/
}
}
{
fast long count;
fast char * word_ptr;
char * end_ptr;
Scan += 1;
/* Is there enough space to read the count? */
end_ptr = (((char *) Scan) + (2 * (sizeof (format_word))));
if (end_ptr > ((char *) scan_buffer_top))
{
long dw;
extend_scan_buffer (end_ptr, To);
BCH_START_CLOSURE_RELOCATION (Scan - 1);
count = (MANIFEST_CLOSURE_COUNT (Scan));
word_ptr = (FIRST_MANIFEST_CLOSURE_ENTRY (Scan));
dw = (word_ptr - end_ptr);
end_ptr = (end_scan_buffer_extension (end_ptr));
word_ptr = (end_ptr + dw);
Scan = ((SCHEME_OBJECT *) (end_ptr - (2 * (sizeof (format_word)))));
}
else
{
BCH_START_CLOSURE_RELOCATION (Scan - 1);
count = (MANIFEST_CLOSURE_COUNT (Scan));
word_ptr = (FIRST_MANIFEST_CLOSURE_ENTRY (Scan));
}
end_ptr = ((char *) (MANIFEST_CLOSURE_END (Scan, count)));
for ( ; ((--count) >= 0);
(word_ptr = (NEXT_MANIFEST_CLOSURE_ENTRY (word_ptr))))
{
if ((CLOSURE_ENTRY_END (word_ptr)) > ((char *) scan_buffer_top))
{
char * entry_end;
long de, dw;
entry_end = (CLOSURE_ENTRY_END (word_ptr));
de = (end_ptr - entry_end);
dw = (entry_end - word_ptr);
extend_scan_buffer (entry_end, To);
relocate_manifest_closure (false);
entry_end = (end_scan_buffer_extension (entry_end));
word_ptr = (entry_end - dw);
end_ptr = (entry_end + de);
}
else
relocate_manifest_closure (false);
}
Scan = ((SCHEME_OBJECT *) (end_ptr));
BCH_END_CLOSURE_RELOCATION (Scan);
break;
}
case_Cell:
relocate_normal_pointer (copy_cell(), 1);
case TC_REFERENCE_TRAP:
if ((OBJECT_DATUM (Temp)) <= TRAP_MAX_IMMEDIATE)
break; /* It is a non pointer. */
goto purify_pair;
case TC_INTERNED_SYMBOL:
case TC_UNINTERNED_SYMBOL:
if (purify_mode == PURE_COPY)
{
Temp = (MEMORY_REF (Temp, SYMBOL_NAME));
relocate_indirect_setup ();
copy_vector (NULL);
relocate_indirect_end ();
}
/* Fall through. */
case_Fasdump_Pair:
purify_pair:
relocate_normal_pointer (copy_pair(), 2);
case TC_WEAK_CONS:
if (purify_mode == PURE_COPY)
break;
else
relocate_normal_pointer (copy_weak_pair(), 2);
case TC_VARIABLE:
case_Triple:
relocate_normal_pointer (copy_triple(), 3);
case_Quadruple:
relocate_normal_pointer (copy_quadruple(), 4);
case TC_BIG_FLONUM:
relocate_flonum_setup ();
goto Move_Vector;
case TC_COMPILED_CODE_BLOCK:
case TC_ENVIRONMENT:
if (purify_mode == PURE_COPY)
break;
/* Fall through */
case_Purify_Vector:
relocate_normal_setup ();
Move_Vector:
copy_vector (NULL);
relocate_normal_end ();
case TC_FUTURE:
relocate_normal_setup();
if (!(Future_Spliceable (Temp)))
goto Move_Vector;
*Scan = (Future_Value (Temp));
Scan -= 1;
continue;
default:
GC_BAD_TYPE ("purifyloop");
/* Fall Through */
case_Non_Pointer:
break;
}
}
end_purifyloop:
*To_ptr = To;
*To_Address_ptr = To_Address;
return (Scan);
}
/* This is not paranoia!
The two words in the header may overflow the free buffer.
*/
static SCHEME_OBJECT *
DEFUN (purify_header_overflow, (free_buffer), SCHEME_OBJECT *free_buffer)
{
SCHEME_OBJECT *scan_buffer;
long delta;
delta = (free_buffer - free_buffer_top);
free_buffer = (dump_and_reset_free_buffer (delta, NULL));
scan_buffer = (dump_and_reload_scan_buffer (0, NULL));
if ((scan_buffer + delta) != free_buffer)
{
gc_death (TERM_EXIT,
"purify: scan and free do not meet at the end",
(scan_buffer + delta), free_buffer);
/*NOTREACHED*/
}
return (free_buffer);
}
static SCHEME_OBJECT
DEFUN (purify, (object, flag),
SCHEME_OBJECT object AND SCHEME_OBJECT flag)
{
long length, pure_length, delta;
SCHEME_OBJECT
* result, * free_buffer_ptr,
* old_free, * block_start,
* scan_start, * new_free;
initialize_weak_pair_transport (Constant_Top);
free_buffer_ptr = (initialize_free_buffer ());
old_free = Free_Constant;
new_free = old_free;
block_start = ((SCHEME_OBJECT *) (ALIGN_DOWN_TO_IO_PAGE (old_free)));
delta = (old_free - block_start);
if (delta != 0)
{
fast SCHEME_OBJECT *ptr, *ptrend;
for (ptr = block_start, ptrend = old_free; ptr != ptrend; )
*free_buffer_ptr++ = *ptr++;
}
new_free += 2;
*free_buffer_ptr++ = SHARP_F; /* Pure block header. */
*free_buffer_ptr++ = object;
if (free_buffer_ptr >= free_buffer_top)
free_buffer_ptr =
(dump_and_reset_free_buffer ((free_buffer_ptr - free_buffer_top), NULL));
if (flag == SHARP_T)
{
scan_start = ((initialize_scan_buffer (block_start)) + delta);
result = (purifyloop (scan_start, &free_buffer_ptr,
&new_free, PURE_COPY));
if (result != free_buffer_ptr)
{
gc_death (TERM_BROKEN_HEART,
"purify: pure copy ended too early",
result, free_buffer_ptr);
/*NOTREACHED*/
}
pure_length = ((new_free - old_free) + 1);
}
else
pure_length = 3;
new_free += 2;
*free_buffer_ptr++ = (MAKE_OBJECT (TC_MANIFEST_SPECIAL_NM_VECTOR, 1));
*free_buffer_ptr++ = (MAKE_OBJECT (CONSTANT_PART, pure_length));
if (free_buffer_ptr >= free_buffer_top)
free_buffer_ptr = (purify_header_overflow (free_buffer_ptr));
scan_start = ((initialize_scan_buffer (block_start)) + delta);
if (flag == SHARP_T)
result = (purifyloop (scan_start, &free_buffer_ptr,
&new_free, CONSTANT_COPY));
else
result = (GCLoop (scan_start, &free_buffer_ptr, &new_free));
if (result != free_buffer_ptr)
{
gc_death (TERM_BROKEN_HEART, "purify: constant copy ended too early",
result, free_buffer_ptr);
/*NOTREACHED*/
}
new_free += 2;
length = (new_free - old_free);
*free_buffer_ptr++ = (MAKE_OBJECT (TC_MANIFEST_SPECIAL_NM_VECTOR, 1));
*free_buffer_ptr++ = (MAKE_OBJECT (END_OF_BLOCK, (length - 1)));
if (free_buffer_ptr >= free_buffer_top)
free_buffer_ptr = (purify_header_overflow (free_buffer_ptr));
end_transport (NULL);
if (!(TEST_CONSTANT_TOP (new_free)))
{
gc_death (TERM_NO_SPACE, "purify: object too large", NULL, NULL);
/*NOTREACHED*/
}
final_reload (block_start,
(new_free - block_start),
"the new constant space block");
*old_free++ = (MAKE_OBJECT (TC_MANIFEST_SPECIAL_NM_VECTOR, pure_length));
*old_free = (MAKE_OBJECT (PURE_PART, (length - 1)));
Free_Constant = new_free;
SET_CONSTANT_TOP ();
GC (1);
return (SHARP_T);
}
/* Stub. Not needed by this version. Terminates Scheme if invoked. */
SCHEME_OBJECT
DEFUN (Purify_Pass_2, (info), SCHEME_OBJECT info)
{
gc_death (TERM_EXIT, "Purify_Pass_2 invoked", NULL, NULL);
/*NOTREACHED*/
}
/* (PRIMITIVE-PURIFY OBJECT PURE? SAFETY-MARGIN)
Copy an object from the heap into constant space. It should only
be used through the wrapper provided in the Scheme runtime system.
To purify an object we just copy it into Pure Space in two
parts with the appropriate headers and footers. The actual
copying is done by PurifyLoop above.
Once the copy is complete we run a full GC which handles the
broken hearts which now point into pure space.
This primitive does not return normally. It always escapes into
the interpreter because some of its cached registers (eg. History)
have changed. */
DEFINE_PRIMITIVE ("PRIMITIVE-PURIFY", Prim_primitive_purify, 3, 3, 0)
{
SCHEME_OBJECT object, daemon;
SCHEME_OBJECT result;
PRIMITIVE_HEADER (3);
PRIMITIVE_CANONICALIZE_CONTEXT ();
STACK_SANITY_CHECK ("PURIFY");
Save_Time_Zone (Zone_Purify);
TOUCH_IN_PRIMITIVE ((ARG_REF (1)), object);
CHECK_ARG (2, BOOLEAN_P);
GC_Reserve = (arg_nonnegative_integer (3));
ENTER_CRITICAL_SECTION ("purify");
{
SCHEME_OBJECT purify_result;
SCHEME_OBJECT words_free;
purify_result = (purify (object, (ARG_REF (2))));
words_free = (LONG_TO_UNSIGNED_FIXNUM (MemTop - Free));
result = (MAKE_POINTER_OBJECT (TC_LIST, Free));
(*Free++) = purify_result;
(*Free++) = words_free;
}
POP_PRIMITIVE_FRAME (3);
daemon = (Get_Fixed_Obj_Slot (GC_Daemon));
if (daemon == SHARP_F)
{
Val = result;
EXIT_CRITICAL_SECTION ({});
PRIMITIVE_ABORT (PRIM_POP_RETURN);
/*NOTREACHED*/
}
RENAME_CRITICAL_SECTION ("purify daemon");
Will_Push (CONTINUATION_SIZE + (STACK_ENV_EXTRA_SLOTS + 1));
Store_Expression (result);
Store_Return (RC_NORMAL_GC_DONE);
Save_Cont ();
STACK_PUSH (daemon);
STACK_PUSH (STACK_FRAME_HEADER);
Pushed ();
PRIMITIVE_ABORT(PRIM_APPLY);
/*NOTREACHED*/
}