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/*
* Copyright (c) 2006-2008 YAMAMOTO Kengo <yamaken AT bp.iij4u.or.jp>
* All rights reserved.
*
* THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
* OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
*
* Permission is hereby granted to use or copy this program
* for any purpose, provided the above notices are retained on all copies.
* Permission to modify the code and to distribute modified code is granted,
* provided the above notices are retained, and a notice that the code was
* modified is included with the above copyright notice.
*/
#include <assert.h>
#include "gcroots.h"
#include "private/gcroots_priv.h"
#include "private/gc_priv.h"
#if ((defined(__MWERKS__) && !defined(POWERPC)) \
|| (!defined(USE_ASM_PUSH_REGS) && defined(M68K)) \
|| defined(ALPHA) || defined(MIPS) || defined(POWERPC))
#define EXTRA_CONTEXT_IN_REGS
#endif
#ifdef THREADS
#error "threaded configuration is not supported (yet)"
#endif
#ifdef EXTRA_CONTEXT_IN_REGS
/* must always be capable of all push */
#define PUSHED_REGS_SIZE 64
#endif
struct _GCROOTS_context {
void *stack_base;
#ifdef IA64
void *register_stack_bs_base;
#endif
GCROOTS_mark_proc mark;
GC_bool use_system_stack_bottom;
};
static void find_obj(void *start, void *end, int is_certain, int is_aligned);
static void *findee;
static int found;
#if defined(SPARC) || defined(IA64)
extern ptr_t GC_save_regs_ret_val;
#endif
#ifdef EXTRA_CONTEXT_IN_REGS
static int n_pushed_regs;
static word pushed_regs[PUSHED_REGS_SIZE];
#endif
GCROOTS_context *
GCROOTS_init(GCROOTS_context_alloc_proc allocator, GCROOTS_mark_proc marker,
int scan_entire_system_stack)
{
GCROOTS_context *ctx;
assert(allocator);
assert(marker);
/* scan_entire_system_stack is not supported yet */
assert(!scan_entire_system_stack);
ctx = (*allocator)(sizeof(GCROOTS_context));
if (ctx) {
ctx->mark = marker;
ctx->use_system_stack_bottom = scan_entire_system_stack;
ctx->stack_base = NULL;
#ifdef IA64
ctx->register_stack_bs_base = NULL;
#endif
#ifdef EXTRA_CONTEXT_IN_REGS
n_pushed_regs = 0;
#endif
}
return ctx;
}
void
GCROOTS_fin(GCROOTS_context *ctx)
{
assert(ctx);
/* Nothing to do for this implementation. Caller must free ctx. */
}
void *
GCROOTS_call_with_gc_ready_stack(GCROOTS_context *ctx,
GCROOTS_user_proc proc, void *arg)
{
void *ret;
word stack_top; /* approx */
volatile GCROOTS_user_proc anti_inline_proc;
assert(ctx);
assert(proc);
if (!ctx->stack_base) {
ctx->stack_base = &stack_top;
#ifdef IA64
ctx->register_stack_bs_base = GC_save_regs_in_stack();
#endif
}
anti_inline_proc = proc;
ret = (*anti_inline_proc)(arg);
if (ctx->stack_base == &stack_top) {
ctx->stack_base = NULL;
#ifdef IA64
ctx->register_stack_bs_base = NULL;
#endif
}
return ret;
}
void
GCROOTS_mark(GCROOTS_context *ctx)
{
assert(ctx);
GC_push_regs_and_stack((ptr_t)ctx);
}
int
GCROOTS_is_protected_context(GCROOTS_context *ctx)
{
assert(ctx);
return (ctx->stack_base) ? TRUE : FALSE;
}
int
GCROOTS_is_protected(GCROOTS_context *ctx, void *obj)
{
GCROOTS_context tmp_ctx;
assert(ctx);
if (!GCROOTS_is_protected_context(ctx))
return FALSE;
tmp_ctx = *ctx;
tmp_ctx.mark = find_obj; /* not actually a mark function */
findee = obj;
found = FALSE;
GCROOTS_mark(&tmp_ctx);
return found;
}
/* thread unsafe */
static void
find_obj(void *start, void *end, int is_certain, int is_aligned)
{
void **p;
int offset;
offset = 0;
do {
for (p = (void **)start + offset; p < (void **)end; p++) {
if (*p == findee) {
found = TRUE;
return;
}
}
offset += ALIGNOF_VOID_P;
} while (!is_aligned
&& SIZEOF_VOID_P != ALIGNOF_VOID_P
&& offset % SIZEOF_VOID_P);
}
/*
* Substitution functions for original Boehm GC
*/
/* mark immediately despite the name 'push_current_stack' */
void
GC_push_current_stack(ptr_t cold_gc_frame, void *context)
{
word stack_top; /* approx */
#ifdef IA64
void *bsp;
#endif
GCROOTS_context *ctx;
ctx = (GCROOTS_context *)cold_gc_frame;
assert(ctx->stack_base || ctx->use_system_stack_bottom);
#ifdef STACK_GROWS_DOWN
(*ctx->mark)(&stack_top + 1, ctx->stack_base, FALSE, FALSE);
#else
(*ctx->mark)((word *)ctx->stack_base + 1, &stack_top, FALSE, FALSE);
#endif
#ifdef IA64
/* register stack backing store grows upward */
bsp = GC_save_regs_ret_val;
(*ctx->mark)(ctx->register_stack_bs_base, bsp, FALSE, TRUE);
#endif
#ifdef EXTRA_CONTEXT_IN_REGS
assert(n_pushed_regs <= PUSHED_REGS_SIZE);
(*ctx->mark)(pushed_regs, &pushed_regs[n_pushed_regs], FALSE, TRUE);
n_pushed_regs = 0;
#endif
}
#ifdef EXTRA_CONTEXT_IN_REGS
# if defined(MSWIN32) || defined(MSWINCE)
void __cdecl GC_push_one(word p)
# else
void GC_push_one(word p)
# endif
{
pushed_regs[n_pushed_regs++] = p;
}
#endif /* EXTRA_CONTEXT_IN_REGS */
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