# include <stdio.h>
# include "private/gc_pmark.h"
+#if defined(MSWIN32) && defined(__GNUC__)
+# include <excpt.h>
+#endif
+
/* We put this here to minimize the risk of inlining. */
/*VARARGS*/
#ifdef __WATCOMC__
/* remains valid until all marking is complete. */
/* A zero value indicates that it's OK to miss some */
/* register values. */
-GC_bool GC_mark_some(cold_gc_frame)
-ptr_t cold_gc_frame;
-{
+/* We hold the allocation lock. In the case of */
+/* incremental collection, the world may not be stopped.*/
#ifdef MSWIN32
- /* Windows 98 appears to asynchronously create and remove writable */
- /* memory mappings, for reasons we haven't yet understood. Since */
- /* we look for writable regions to determine the root set, we may */
- /* try to mark from an address range that disappeared since we */
- /* started the collection. Thus we have to recover from faults here. */
- /* This code does not appear to be necessary for Windows 95/NT/2000. */
- /* Note that this code should never generate an incremental GC write */
- /* fault. */
- __try {
+ /* For win32, this is called after we establish a structured */
+ /* exception handler, in case Windows unmaps one of our root */
+ /* segments. See below. In either case, we acquire the */
+ /* allocator lock long before we get here. */
+ GC_bool GC_mark_some_inner(cold_gc_frame)
+ ptr_t cold_gc_frame;
+#else
+ GC_bool GC_mark_some(cold_gc_frame)
+ ptr_t cold_gc_frame;
#endif
+{
switch(GC_mark_state) {
case MS_NONE:
return(FALSE);
ABORT("GC_mark_some: bad state");
return(FALSE);
}
+}
+
+
#ifdef MSWIN32
- } __except (GetExceptionCode() == EXCEPTION_ACCESS_VIOLATION ?
- EXCEPTION_EXECUTE_HANDLER : EXCEPTION_CONTINUE_SEARCH) {
-# ifdef CONDPRINT
- if (GC_print_stats) {
- GC_printf0("Caught ACCESS_VIOLATION in marker. "
- "Memory mapping disappeared.\n");
+
+# ifdef __GNUC__
+
+ typedef struct {
+ EXCEPTION_REGISTRATION ex_reg;
+ void *alt_path;
+ } ext_ex_regn;
+
+
+ static EXCEPTION_DISPOSITION mark_ex_handler(
+ struct _EXCEPTION_RECORD *ex_rec,
+ void *est_frame,
+ struct _CONTEXT *context,
+ void *disp_ctxt)
+ {
+ if (ex_rec->ExceptionCode == STATUS_ACCESS_VIOLATION) {
+ ext_ex_regn *xer = (ext_ex_regn *)est_frame;
+
+ /* Unwind from the inner function assuming the standard */
+ /* function prologue. */
+ /* Assumes code has not been compiled with */
+ /* -fomit-frame-pointer. */
+ context->Esp = context->Ebp;
+ context->Ebp = *((DWORD *)context->Esp);
+ context->Esp = context->Esp - 8;
+
+ /* Resume execution at the "real" handler within the */
+ /* wrapper function. */
+ context->Eip = (DWORD )(xer->alt_path);
+
+ return ExceptionContinueExecution;
+
+ } else {
+ return ExceptionContinueSearch;
+ }
+ }
+# endif /* __GNUC__ */
+
+
+ GC_bool GC_mark_some(cold_gc_frame)
+ ptr_t cold_gc_frame;
+ {
+ GC_bool ret_val;
+
+# ifndef __GNUC__
+ /* Windows 98 appears to asynchronously create and remove */
+ /* writable memory mappings, for reasons we haven't yet */
+ /* understood. Since we look for writable regions to */
+ /* determine the root set, we may try to mark from an */
+ /* address range that disappeared since we started the */
+ /* collection. Thus we have to recover from faults here. */
+ /* This code does not appear to be necessary for Windows */
+ /* 95/NT/2000. Note that this code should never generate */
+ /* an incremental GC write fault. */
+
+ __try {
+
+# else /* __GNUC__ */
+
+ /* Manually install an exception handler since GCC does */
+ /* not yet support Structured Exception Handling (SEH) on */
+ /* Win32. */
+
+ ext_ex_regn er;
+
+ er.alt_path = &&handle_ex;
+ er.ex_reg.handler = mark_ex_handler;
+ asm volatile ("movl %%fs:0, %0" : "=r" (er.ex_reg.prev));
+ asm volatile ("movl %0, %%fs:0" : : "r" (&er));
+
+# endif /* __GNUC__ */
+
+ ret_val = GC_mark_some_inner(cold_gc_frame);
+
+# ifndef __GNUC__
+
+ } __except (GetExceptionCode() == EXCEPTION_ACCESS_VIOLATION ?
+ EXCEPTION_EXECUTE_HANDLER : EXCEPTION_CONTINUE_SEARCH) {
+
+# else /* __GNUC__ */
+
+ /* Prevent GCC from considering the following code unreachable */
+ /* and thus eliminating it. */
+ if (er.alt_path != 0)
+ goto rm_handler;
+
+handle_ex:
+ /* Execution resumes from here on an access violation. */
+
+# endif /* __GNUC__ */
+
+# ifdef CONDPRINT
+ if (GC_print_stats) {
+ GC_printf0("Caught ACCESS_VIOLATION in marker. "
+ "Memory mapping disappeared.\n");
+ }
+# endif /* CONDPRINT */
+
+ /* We have bad roots on the stack. Discard mark stack. */
+ /* Rescan from marked objects. Redetermine roots. */
+ GC_invalidate_mark_state();
+ scan_ptr = 0;
+
+ ret_val = FALSE;
+
+# ifndef __GNUC__
+
}
-# endif /* CONDPRINT */
- /* We have bad roots on the stack. Discard mark stack. */
- /* Rescan from marked objects. Redetermine roots. */
- GC_invalidate_mark_state();
- scan_ptr = 0;
- return FALSE;
+
+# else /* __GNUC__ */
+
+rm_handler:
+ /* Uninstall the exception handler */
+ asm volatile ("mov %0, %%fs:0" : : "r" (er.ex_reg.prev));
+
+# endif /* __GNUC__ */
+
+ return ret_val;
}
#endif /* MSWIN32 */
-}
GC_bool GC_mark_stack_empty()
/* for the large object. */
/* - just return current if it does not point to a large object. */
/*ARGSUSED*/
-# ifdef PRINT_BLACK_LIST
- ptr_t GC_find_start(current, hhdr, new_hdr_p, source)
- ptr_t source;
-# else
- ptr_t GC_find_start(current, hhdr, new_hdr_p)
-# define source 0
-# endif
+ptr_t GC_find_start(current, hhdr, new_hdr_p)
register ptr_t current;
register hdr *hhdr, **new_hdr_p;
{
current = current - HBLKSIZE*(word)hhdr;
hhdr = HDR(current);
} while(IS_FORWARDING_ADDR_OR_NIL(hhdr));
- /* current points to the start of the large object */
- if (hhdr -> hb_flags & IGNORE_OFF_PAGE) return(0);
+ /* current points to near the start of the large object */
+ if (hhdr -> hb_flags & IGNORE_OFF_PAGE) return(orig);
if ((word *)orig - (word *)current
>= (ptrdiff_t)(hhdr->hb_sz)) {
/* Pointer past the end of the block */
} else {
return(current);
}
-# undef source
}
void GC_invalidate_mark_state()
/* Large length. */
/* Process part of the range to avoid pushing too much on the */
/* stack. */
+ GC_ASSERT(descr < (word)GC_greatest_plausible_heap_addr
+ - (word)GC_least_plausible_heap_addr);
# ifdef PARALLEL_MARK
# define SHARE_BYTES 2048
if (descr > SHARE_BYTES && GC_parallel
&& mark_stack_top < mark_stack_limit - 1) {
int new_size = (descr/2) & ~(sizeof(word)-1);
- GC_ASSERT(descr < GC_greatest_plausible_heap_addr
- - GC_least_plausible_heap_addr);
mark_stack_top -> mse_start = current_p;
mark_stack_top -> mse_descr = new_size + sizeof(word);
/* makes sure we handle */
while (descr != 0) {
if ((signed_word)descr < 0) {
current = *current_p;
+ FIXUP_POINTER(current);
if ((ptr_t)current >= least_ha && (ptr_t)current < greatest_ha) {
- PREFETCH(current);
+ PREFETCH((ptr_t)current);
HC_PUSH_CONTENTS((ptr_t)current, mark_stack_top,
mark_stack_limit, current_p, exit1);
}
PREFETCH((ptr_t)limit - PREF_DIST*CACHE_LINE_SIZE);
GC_ASSERT(limit >= current_p);
deferred = *limit;
+ FIXUP_POINTER(deferred);
limit = (word *)((char *)limit - ALIGNMENT);
if ((ptr_t)deferred >= least_ha && (ptr_t)deferred < greatest_ha) {
- PREFETCH(deferred);
+ PREFETCH((ptr_t)deferred);
break;
}
if (current_p > limit) goto next_object;
/* Unroll once, so we don't do too many of the prefetches */
/* based on limit. */
deferred = *limit;
+ FIXUP_POINTER(deferred);
limit = (word *)((char *)limit - ALIGNMENT);
if ((ptr_t)deferred >= least_ha && (ptr_t)deferred < greatest_ha) {
- PREFETCH(deferred);
+ PREFETCH((ptr_t)deferred);
break;
}
if (current_p > limit) goto next_object;
/* Since HC_PUSH_CONTENTS expands to a lot of code, */
/* we don't. */
current = *current_p;
+ FIXUP_POINTER(current);
PREFETCH((ptr_t)current_p + PREF_DIST*CACHE_LINE_SIZE);
if ((ptr_t)current >= least_ha && (ptr_t)current < greatest_ha) {
/* Prefetch the contents of the object we just pushed. It's */
/* likely we will need them soon. */
- PREFETCH(current);
+ PREFETCH((ptr_t)current);
HC_PUSH_CONTENTS((ptr_t)current, mark_stack_top,
mark_stack_limit, current_p, exit2);
}
mse *top = local - 1;
unsigned i = 0;
+ /* Make sure that prior writes to the mark stack are visible. */
+ /* On some architectures, the fact that the reads are */
+ /* volatile should suffice. */
+# if !defined(IA64) && !defined(HP_PA) && !defined(I386)
+ GC_memory_barrier();
+# endif
GC_ASSERT(high >= low-1 && high - low + 1 <= GC_mark_stack_size);
for (p = low; p <= high && i <= max; ++p) {
word descr = *(volatile word *) &(p -> mse_descr);
+ /* In the IA64 memory model, the following volatile store is */
+ /* ordered after this read of descr. Thus a thread must read */
+ /* the original nonzero value. HP_PA appears to be similar, */
+ /* and if I'm reading the P4 spec correctly, X86 is probably */
+ /* also OK. In some other cases we need a barrier. */
+# if !defined(IA64) && !defined(HP_PA) && !defined(I386)
+ GC_memory_barrier();
+# endif
if (descr != 0) {
*(volatile word *) &(p -> mse_descr) = 0;
+ /* More than one thread may get this entry, but that's only */
+ /* a minor performance problem. */
++top;
top -> mse_descr = descr;
top -> mse_start = p -> mse_start;
- GC_ASSERT( top -> mse_descr & GC_DS_TAGS != GC_DS_LENGTH ||
- top -> mse_descr < GC_greatest_plausible_heap_addr
- - GC_least_plausible_heap_addr);
- /* There is no synchronization here. We assume that at */
- /* least one thread will see the original descriptor. */
- /* Otherwise we need a barrier. */
- /* More than one thread may get this entry, but that's only */
- /* a minor performance problem. */
+ GC_ASSERT( (top -> mse_descr & GC_DS_TAGS) != GC_DS_LENGTH ||
+ top -> mse_descr < (ptr_t)GC_greatest_plausible_heap_addr
+ - (ptr_t)GC_least_plausible_heap_addr);
/* If this is a big object, count it as */
/* size/256 + 1 objects. */
++i;
BCOPY(low, my_start, stack_size * sizeof(mse));
GC_ASSERT(GC_mark_stack_top = my_top);
# if !defined(IA64) && !defined(HP_PA)
- GC_memory_write_barrier();
+ GC_memory_barrier();
# endif
/* On IA64, the volatile write acts as a release barrier. */
GC_mark_stack_top = my_top + stack_size;
/* -specific code. */
/* Mark using the local mark stack until the global mark stack is empty */
-/* and ther are no active workers. Update GC_first_nonempty to reflect */
+/* and there are no active workers. Update GC_first_nonempty to reflect */
/* progress. */
/* Caller does not hold mark lock. */
/* Caller has already incremented GC_helper_count. We decrement it, */
return;
}
/* else there's something on the stack again, or */
- /* another help may push something. */
+ /* another helper may push something. */
GC_active_count++;
GC_ASSERT(GC_active_count > 0);
GC_release_mark_lock();
GC_acquire_mark_lock();
GC_ASSERT(I_HOLD_LOCK());
- GC_ASSERT(!GC_help_wanted);
- GC_ASSERT(GC_active_count == 0);
+ /* This could be a GC_ASSERT, but it seems safer to keep it on */
+ /* all the time, especially since it's cheap. */
+ if (GC_help_wanted || GC_active_count != 0 || GC_helper_count != 0)
+ ABORT("Tried to start parallel mark in bad state");
# ifdef PRINTSTATS
GC_printf1("Starting marking for mark phase number %lu\n",
(unsigned long)GC_mark_no);
ptr_t bottom;
ptr_t top;
{
- word * b = (word *)(((long) bottom + ALIGNMENT-1) & ~(ALIGNMENT-1));
- word * t = (word *)(((long) top) & ~(ALIGNMENT-1));
+ word * b = (word *)(((word) bottom + ALIGNMENT-1) & ~(ALIGNMENT-1));
+ word * t = (word *)(((word) top) & ~(ALIGNMENT-1));
register word *p;
register word q;
register word *lim;
# define GC_least_plausible_heap_addr least_ha
if (top == 0) return;
- /* check all pointers in range and put in push if they appear */
- /* to be valid. */
+ /* check all pointers in range and push if they appear */
+ /* to be valid. */
lim = t - 1 /* longword */;
for (p = b; p <= lim; p = (word *)(((char *)p) + ALIGNMENT)) {
q = *p;
ptr_t top;
ptr_t cold_gc_frame;
{
- if (GC_all_interior_pointers) {
+ if (!NEED_FIXUP_POINTER && GC_all_interior_pointers) {
# define EAGER_BYTES 1024
/* Push the hot end of the stack eagerly, so that register values */
/* saved inside GC frames are marked before they disappear. */
GC_push_all_stack(bottom, top);
return;
}
+ GC_ASSERT(bottom <= cold_gc_frame && cold_gc_frame <= top);
# ifdef STACK_GROWS_DOWN
- GC_push_all_eager(bottom, cold_gc_frame);
GC_push_all(cold_gc_frame - sizeof(ptr_t), top);
+ GC_push_all_eager(bottom, cold_gc_frame);
# else /* STACK_GROWS_UP */
- GC_push_all_eager(cold_gc_frame, top);
GC_push_all(bottom, cold_gc_frame + sizeof(ptr_t));
+ GC_push_all_eager(cold_gc_frame, top);
# endif /* STACK_GROWS_UP */
} else {
GC_push_all_eager(bottom, top);
ptr_t bottom;
ptr_t top;
{
- if (GC_all_interior_pointers) {
+ if (!NEED_FIXUP_POINTER && GC_all_interior_pointers) {
GC_push_all(bottom, top);
} else {
GC_push_all_eager(bottom, top);
{
register int sz = hhdr -> hb_sz;
- if (sz < MAXOBJSZ) {
+ if (sz <= MAXOBJSZ) {
return(GC_page_was_dirty(h));
} else {
register ptr_t p = (ptr_t)h;
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