pike.git/src/gc.c:e6cce8b4b5bccad1d05ba0be7a0b1992612c5e9e

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||| This file a part of Pike, and is copyright by Fredrik Hubinette ||| Pike is distributed as GPL (General Public License) ||| See the files COPYING and DISCLAIMER for more information. \*/ /**/ #include "global.h" struct callback *gc_evaluator_callback=0; #include "array.h" #include "multiset.h" #include "mapping.h" #include "object.h" #include "program.h" #include "stralloc.h" #include "stuff.h" #include "error.h" #include "pike_memory.h" #include "pike_macros.h" #include "pike_types.h" #include "time_stuff.h" #include "constants.h" #include "interpret.h" #include "bignum.h" #include "gc.h" #include "main.h" #include <math.h> #include "block_alloc.h" RCSID("$Id: gc.c,v 1.122 2000/08/16 10:35:48 grubba Exp $"); /* Run garbage collect approximately every time * 20 percent of all arrays, objects and programs is * garbage. */ #define GC_CONST 20 #define MIN_ALLOC_THRESHOLD 1000 #define MAX_ALLOC_THRESHOLD 10000000 #define MULTIPLIER 0.9 #define MARKER_CHUNK_SIZE 1023 #define GC_LINK_CHUNK_SIZE 31 /* The gc will free all things with no external references that isn't * referenced by undestructed objects with destroy() lfuns (known as * "live" objects). Live objects without external references are then * destructed and garbage collected with normal refcount garbing * (which might leave dead garbage around for the next gc). These live * objects are destructed in an order that tries to be as well defined * as possible using several rules: * * o If an object A references B single way, then A is destructed * before B. * o If A and B are in a cycle, and there is a reference somewhere * from B to A that is weaker than any reference from A to B, then * A is destructed before B. * o Weak references are considered weaker than normal ones, and both * are considered weaker than strong references. * o Strong references are used in special cases like parent object * references. There can never be a cycle consisting only of strong * references. (This means the gc will never destruct a parent * object before all childs has been destructed.) * * The gc tries to detect and warn about cases where there are live * objects with no well defined order between them. There are cases * that are missed by this detection, though. * * Things that aren't live objects but are referenced from them are * still intact during this destruct pass, so it's entirely possible * to save these things by adding external references to them. * However, it's not possible for live objects to save themselves or * other live objects; all live objects that didn't have external * references at the start of the gc pass will be destructed * regardless of added references. * * Things that have only weak references at the start of the gc pass * will be freed. That's done before the live object destruct pass. */ /* #define GC_VERBOSE */ /* #define GC_CYCLE_DEBUG */ /* #define GC_STACK_DEBUG */ #if defined(GC_VERBOSE) && !defined(PIKE_DEBUG) #undef GC_VERBOSE #endif #ifdef GC_VERBOSE #define GC_VERBOSE_DO(X) X #else #define GC_VERBOSE_DO(X) #endif /* Kludge to avoid some loss of precision warnings. */ #ifdef __ECL static inline long CAST_TO_LONG(ptrdiff_t val) { return DO_NOT_WARN((long)val); } #else /* !__ECL */ #define CAST_TO_LONG(val) ((long)(val)) #endif /* __ECL */ INT32 num_objects = 1; /* Account for empty_array. */ INT32 num_allocs =0; ptrdiff_t alloc_threshold = MIN_ALLOC_THRESHOLD; PMOD_EXPORT int Pike_in_gc = 0; struct pike_queue gc_mark_queue; time_t last_gc; struct gc_frame { struct gc_frame *back; /* Previous stack frame. */ void *data; union { struct { /* Pop frame. */ struct gc_frame *prev; /* Previous frame in rec_list. */ struct gc_frame *next; /* Next pointer in rec_list and kill_list. */ unsigned INT16 cycle; /* Cycle id number. */ } pop; struct { /* Link frame. */ gc_cycle_check_cb *checkfn; int weak; } link; } u; unsigned INT16 frameflags; }; #define GC_POP_FRAME 0x01 #define GC_WEAK_REF 0x02 #define GC_STRONG_REF 0x04 #define GC_OFF_STACK 0x08 #ifdef PIKE_DEBUG #define GC_LINK_FREED 0x10 #define GC_FOLLOWED_NONSTRONG 0x20 #endif #undef BLOCK_ALLOC_NEXT #define BLOCK_ALLOC_NEXT back BLOCK_ALLOC(gc_frame,GC_LINK_CHUNK_SIZE) #define PREV(frame) ((frame)->u.pop.prev) #define NEXT(frame) ((frame)->u.pop.next) #define CYCLE(frame) ((frame)->u.pop.cycle) #ifdef PIKE_DEBUG #define CHECK_POP_FRAME(frame) do { \ if ((frame)->frameflags & GC_LINK_FREED) \ gc_fatal((frame)->data, 0, "Accessing freed gc_frame.\n"); \ if (!((frame)->frameflags & GC_POP_FRAME)) \ gc_fatal((frame)->data, 0, #frame " is not a pop frame.\n"); \ if (NEXT(PREV(frame)) != (frame)) \ gc_fatal((frame)->data, 0, \ "Pop frame pointers are inconsistent.\n"); \ } while (0) #else #define CHECK_POP_FRAME(frame) do {} while (0) #endif static struct gc_frame rec_list = {0, 0, {{0, 0, 0}}, GC_POP_FRAME}; static struct gc_frame *gc_rec_last = &rec_list, *gc_rec_top = 0; static struct gc_frame *kill_list = 0; static unsigned last_cycle; size_t gc_ext_weak_refs; /* gc_frame objects are used as frames in a recursion stack during the * cycle check pass. gc_rec_top points to the current top of the * stack. When a thing is recursed, a pop frame is first pushed on the * stack and then the gc_cycle_check_* function fills in with link * frames for every reference the thing contains. * * rec_list is a double linked list of the pop frames on the stack, * and that list represents the current prospective destruct order. * gc_rec_last points at the last frame in the list and new frames are * linked in after it. A cycle is always treated as one atomic unit, * e.g. it's either popped whole or not at all. That means that * rec_list may contain frames that are no longer on the stack. * * A range of frames which always ends at the end of the list, may be * rotated a number of slots to break a cyclic reference at a chosen * point. The stack of link frames are rotated simultaneously. * * Frames for live objects are linked into the beginning of kill_list * when they're popped from rec_list. * * The cycle check functions might recurse another round through the * frames that have been recursed already, to propagate the GC_LIVE * flag to things that have been found to be referenced from live * objects. rec_list is not touched at all in this extra round. */ static double objects_alloced = 0.0; static double objects_freed = 0.0; struct callback_list gc_callbacks; struct callback *debug_add_gc_callback(callback_func call, void *arg, callback_func free_func) { return add_to_callback(&gc_callbacks, call, arg, free_func); } static void gc_cycle_pop(void *a); #undef BLOCK_ALLOC_NEXT #define BLOCK_ALLOC_NEXT next #undef INIT_BLOCK #ifdef PIKE_DEBUG #define INIT_BLOCK(X) \ (X)->flags=(X)->refs=(X)->weak_refs=(X)->xrefs=0; \ (X)->saved_refs=-1; \ (X)->frame = 0; #else #define INIT_BLOCK(X) \ (X)->flags=(X)->refs=(X)->weak_refs=0; \ (X)->frame = 0; #endif PTR_HASH_ALLOC(marker,MARKER_CHUNK_SIZE) #ifdef PIKE_DEBUG int gc_in_cycle_check = 0; static unsigned weak_freed, checked, marked, cycle_checked, live_ref; static unsigned max_gc_frames, num_gc_frames = 0; static unsigned gc_extra_refs = 0; void dump_gc_info(void) { fprintf(stderr,"Current number of objects: %ld\n",(long)num_objects); fprintf(stderr,"Objects allocated total : %ld\n",(long)num_allocs); fprintf(stderr," threshold for next gc() : %ld\n",(long)alloc_threshold); fprintf(stderr,"Average allocs per gc() : %f\n",objects_alloced); fprintf(stderr,"Average frees per gc() : %f\n",objects_freed); fprintf(stderr,"Second since last gc() : %ld\n", DO_NOT_WARN((long)TIME(0) - (long)last_gc)); fprintf(stderr,"Projected garbage : %f\n", objects_freed * (double) num_allocs / (double) alloc_threshold); fprintf(stderr,"in_gc : %d\n", Pike_in_gc); } TYPE_T attempt_to_identify(void *something) { struct array *a; struct object *o; struct program *p; struct mapping *m; struct multiset *mu; a=&empty_array; do { if(a==(struct array *)something) return T_ARRAY; a=a->next; }while(a!=&empty_array); for(o=first_object;o;o=o->next) if(o==(struct object *)something) return T_OBJECT; for(p=first_program;p;p=p->next) if(p==(struct program *)something) return T_PROGRAM; for(m=first_mapping;m;m=m->next) if(m==(struct mapping *)something) return T_MAPPING; for(mu=first_multiset;mu;mu=mu->next) if(mu==(struct multiset *)something) return T_MULTISET; if(safe_debug_findstring((struct pike_string *)something)) return T_STRING; return T_UNKNOWN; } void *check_for =0; static char *found_where=""; static void *found_in=0; static int found_in_type=0; void *gc_svalue_location=0; char *fatal_after_gc=0; int gc_debug = 0; #define DESCRIBE_MEM 1 #define DESCRIBE_NO_REFS 2 #define DESCRIBE_SHORT 4 #define DESCRIBE_NO_DMALLOC 8 /* type == -1 means that memblock is a char* and should be * really be printed.. */ void describe_location(void *real_memblock, int real_type, void *location, int indent, int depth, int flags) { struct program *p; void *memblock=0; int type=real_type; if(!location) return; /* fprintf(stderr,"**Location of (short) svalue: %p\n",location); */ if(real_type!=-1) memblock=real_memblock; #ifdef DEBUG_MALLOC if(memblock == 0 || type == -1) { extern void *dmalloc_find_memblock_base(void *); memblock=dmalloc_find_memblock_base(location); } #endif if(type==T_UNKNOWN) type=attempt_to_identify(memblock); if(memblock) fprintf(stderr,"%*s-> from %s %p offset %ld\n", indent,"", get_name_of_type(type), memblock, DO_NOT_WARN((long)((char *)location - (char *)memblock))); else fprintf(stderr,"%*s-> at location %p in unknown memblock (mmaped?)\n", indent,"", location); if(memblock && depth>0) describe_something(memblock,type,indent+2,depth-1,flags | DESCRIBE_MEM); again: switch(type) { case T_UNKNOWN: for(p=first_program;p;p=p->next) { if(memblock == (void *)p->program) { fprintf(stderr,"%*s **In memory block for program at %p\n", indent,"", p); memblock=p; type=T_PROGRAM; goto again; } } break; case T_PROGRAM: { ptrdiff_t e; char *ptr=(char *)location; p=(struct program *)memblock; if(location == (void *)&p->prev) fprintf(stderr,"%*s **In p->prev\n",indent,""); if(location == (void *)&p->next) fprintf(stderr,"%*s **In p->next\n",indent,""); if(p->inherits && ptr >= (char *)p->inherits && ptr < (char*)(p->inherits+p->num_inherits)) { e=((char *)ptr - (char *)(p->inherits)) / sizeof(struct inherit); fprintf(stderr,"%*s **In p->inherits[%ld] (%s)\n",indent,"", DO_NOT_WARN((long)e), p->inherits[e].name ? p->inherits[e].name->str : "no name"); break; } if(p->constants && ptr >= (char *)p->constants && ptr < (char*)(p->constants+p->num_constants)) { e = ((char *)ptr - (char *)(p->constants)) / sizeof(struct program_constant); fprintf(stderr,"%*s **In p->constants[%ld] (%s)\n",indent,"", DO_NOT_WARN((long)e), p->constants[e].name ? p->constants[e].name->str : "no name"); break; } if(p->identifiers && ptr >= (char *)p->identifiers && ptr < (char*)(p->identifiers+p->num_identifiers)) { e = ((char *)ptr - (char *)(p->identifiers)) / sizeof(struct identifier); fprintf(stderr,"%*s **In p->identifiers[%ld] (%s)\n",indent,"", DO_NOT_WARN((long)e), p->identifiers[e].name ? p->identifiers[e].name->str : "no name"); break; } #define FOO(NTYP,TYP,NAME) \ if(location == (void *)&p->NAME) fprintf(stderr,"%*s **In p->" #NAME "\n",indent,""); \ if(ptr >= (char *)p->NAME && ptr<(char*)(p->NAME+p->PIKE_CONCAT(num_,NAME))) \ fprintf(stderr,"%*s **In p->" #NAME "[%ld]\n",indent,"", \ CAST_TO_LONG(((char *)ptr - (char *)(p->NAME)) / sizeof(TYP))); #include "program_areas.h" break; } case T_OBJECT: { struct object *o=(struct object *)memblock; struct program *p; if(location == (void *)&o->parent) fprintf(stderr,"%*s **In o->parent\n",indent,""); if(location == (void *)&o->prog) fprintf(stderr,"%*s **In o->prog\n",indent,""); if(location == (void *)&o->next) fprintf(stderr,"%*s **In o->next\n",indent,""); if(location == (void *)&o->prev) fprintf(stderr,"%*s **In o->prev\n",indent,""); p=o->prog; if(!o->prog) { p=id_to_program(o->program_id); if(p) fprintf(stderr,"%*s **(We are lucky, found program for destructed object)\n",indent,""); } if(p) { INT32 e,d; for(e=0;e<(INT32)p->num_inherits;e++) { struct inherit tmp=p->inherits[e]; char *base=o->storage + tmp.storage_offset; for(d=0;d<(INT32)tmp.prog->num_identifiers;d++) { struct identifier *id=tmp.prog->identifiers+d; if(!IDENTIFIER_IS_VARIABLE(id->identifier_flags)) continue; if(location == (void *)(base + id->func.offset)) { fprintf(stderr,"%*s **In variable %s\n",indent,"",id->name->str); } } if((char *)location >= base && (char *)location <= base + ( tmp.prog->storage_needed - tmp.prog->inherits[0].storage_offset )) { fprintf(stderr,"%*s **In storage for inherit %d",indent,"",e); if(tmp.name) fprintf(stderr," (%s)",tmp.name->str); fprintf(stderr,"\n"); } } } break; } case T_ARRAY: { struct array *a=(struct array *)memblock; struct svalue *s=(struct svalue *)location; fprintf(stderr,"%*s **In index %ld\n",indent,"", DO_NOT_WARN((long)(s-ITEM(a)))); break; } } #ifdef DEBUG_MALLOC /* FIXME: Is the following call correct? * Shouldn't the second argument be an offset? */ dmalloc_describe_location(memblock, location, indent); #endif } static void describe_gc_frame(struct gc_frame *l) { if (l->frameflags & GC_POP_FRAME) fprintf(stderr, "back=%p, prev=%p, next=%p, data=%p, cycle=%u, flags=0x%02x", l->back, PREV(l), NEXT(l), l->data, CYCLE(l), l->frameflags); else fprintf(stderr, "LINK back=%p, data=%p, weak=%d, flags=0x%02x", l->back, l->data, l->u.link.weak, l->frameflags); } static void describe_marker(struct marker *m) { if (m) { fprintf(stderr, "marker at %p: flags=0x%06x, refs=%d, weak=%d, " "xrefs=%d, saved=%d, frame=%p", m, m->flags, m->refs, m->weak_refs, m->xrefs, m->saved_refs, m->frame); #ifdef PIKE_DEBUG if (m->frame) { fputs(" [", stderr); describe_gc_frame(m->frame); putc(']', stderr); } #endif putc('\n', stderr); } else fprintf(stderr, "no marker\n"); } void debug_gc_fatal(void *a, int flags, const char *fmt, ...) { va_list args; va_start(args, fmt); fprintf(stderr, "**"); (void) VFPRINTF(stderr, fmt, args); describe(a); if (flags & 1) locate_references(a); if (flags & 2) fatal_after_gc = "Fatal in garbage collector.\n"; else debug_fatal("Fatal in garbage collector.\n"); } static void gdb_gc_stop_here(void *a, int weak) { fprintf(stderr,"***One %sref found%s.\n", weak ? "weak " : "", found_where?found_where:""); describe_something(found_in, found_in_type, 2, 1, DESCRIBE_NO_DMALLOC); describe_location(found_in , found_in_type, gc_svalue_location,2,1,0); fprintf(stderr,"----------end------------\n"); } void debug_gc_xmark_svalues(struct svalue *s, ptrdiff_t num, char *fromwhere) { found_in=(void *)fromwhere; found_in_type=-1; gc_xmark_svalues(s,num); found_in_type=T_UNKNOWN; found_in=0; } void debug_gc_check_svalues(struct svalue *s, ptrdiff_t num, TYPE_T t, void *data) { found_in=data; found_in_type=t; gc_check_svalues(s,num); found_in_type=T_UNKNOWN; found_in=0; } void debug_gc_check_weak_svalues(struct svalue *s, ptrdiff_t num, TYPE_T t, void *data) { found_in=data; found_in_type=t; gc_check_weak_svalues(s,num); found_in_type=T_UNKNOWN; found_in=0; } void debug_gc_check_short_svalue(union anything *u, TYPE_T type, TYPE_T t, void *data) { found_in=data; found_in_type=t; gc_check_short_svalue(u,type); found_in_type=T_UNKNOWN; found_in=0; } void debug_gc_check_weak_short_svalue(union anything *u, TYPE_T type, TYPE_T t, void *data) { found_in=data; found_in_type=t; gc_check_weak_short_svalue(u,type); found_in_type=T_UNKNOWN; found_in=0; } int debug_gc_check(void *x, TYPE_T t, void *data) { int ret; found_in=data; found_in_type=t; ret=gc_check(x); found_in_type=T_UNKNOWN; found_in=0; return ret; } /* Avoid loss of precision warning. */ #ifdef __ECL static inline long SIZE_T_TO_LONG(size_t x) { return DO_NOT_WARN((long)x); } #else /* !__ECL */ #define SIZE_T_TO_LONG(x) ((long)(x)) #endif /* __ECL */ void low_describe_something(void *a, int t, int indent, int depth, int flags) { struct program *p=(struct program *)a; struct marker *m; if(depth<0) return; if ((m = find_marker(a))) { fprintf(stderr,"%*s**Got gc ",indent,""); describe_marker(m); } switch(t) { case T_FUNCTION: if(attempt_to_identify(a) != T_OBJECT) { fprintf(stderr,"%*s**Builtin function!\n",indent,""); break; } case T_OBJECT: p=((struct object *)a)->prog; fprintf(stderr,"%*s**Parent identifier: %d\n",indent,"",((struct object *)a)->parent_identifier); fprintf(stderr,"%*s**Program id: %ld\n",indent,"",((struct object *)a)->program_id); if (((struct object *)a)->next == ((struct object *)a)) fprintf(stderr, "%*s**The object is fake.\n",indent,""); { struct object *o; for (o = first_object; o && o != (struct object *) a; o = o->next) {} if (!o) fprintf(stderr,"%*s**The object is not on the object link list.\n",indent,""); for (o = objects_to_destruct; o && o != (struct object *) a; o = o->next) {} if (o) fprintf(stderr,"%*s**The object is on objects_to_destruct.\n",indent,""); } if(!p) { fprintf(stderr,"%*s**The object is destructed.\n",indent,""); p=id_to_program(((struct object *)a)->program_id); } if (p) { fprintf(stderr,"%*s**Attempting to describe program object was instantiated from:\n",indent,""); low_describe_something(p, T_PROGRAM, indent, depth, flags); } if( ((struct object *)a)->parent) { fprintf(stderr,"%*s**Describing object's parent:\n",indent,""); describe_something( ((struct object *)a)->parent, t, indent+2,depth-1, (flags | DESCRIBE_SHORT | DESCRIBE_NO_REFS ) & ~ (DESCRIBE_MEM)); }else{ fprintf(stderr,"%*s**There is no parent (any longer?)\n",indent,""); } break; case T_PROGRAM: { char *tmp; INT32 line,pos; int foo=0; fprintf(stderr,"%*s**Program id: %ld\n",indent,"",(long)(p->id)); if(p->flags & PROGRAM_HAS_C_METHODS) { fprintf(stderr,"%*s**The program was written in C.\n",indent,""); } for(pos=0;pos<100;pos++) { tmp=get_line(p->program+pos, p, &line); if(tmp && line) { fprintf(stderr,"%*s**Location: %s:%ld\n",indent,"",tmp,(long)line); foo=1; break; } if(pos+1>=(ptrdiff_t)p->num_program) break; } #if 0 if(!foo && p->num_linenumbers>1 && EXTRACT_UCHAR(p->linenumbers)=='\177') { fprintf(stderr,"%*s**From file: %s\n",indent,"",p->linenumbers+1); foo=1; } #endif if(!foo) { int e; fprintf(stderr,"%*s**identifiers:\n",indent,""); for(e=0;e<p->num_identifier_references;e++) fprintf(stderr,"%*s**** %s\n",indent,"",ID_FROM_INT(p,e)->name->str); fprintf(stderr,"%*s**num inherits: %d\n",indent,"",p->num_inherits); } if(flags & DESCRIBE_MEM) { #define FOO(NUMTYPE,TYPE,NAME) \ fprintf(stderr, "%*s* " #NAME " %p[%ld]\n", \ indent, "", p->NAME, SIZE_T_TO_LONG(p->PIKE_CONCAT(num_,NAME))); #include "program_areas.h" } break; } case T_MULTISET: fprintf(stderr,"%*s**Describing array of multiset:\n",indent,""); debug_dump_array(((struct multiset *)a)->ind); break; case T_ARRAY: fprintf(stderr,"%*s**Describing array:\n",indent,""); debug_dump_array((struct array *)a); break; case T_MAPPING: fprintf(stderr,"%*s**Describing mapping:\n",indent,""); debug_dump_mapping((struct mapping *)a); fprintf(stderr,"%*s**Describing mapping data block:\n",indent,""); describe_something( ((struct mapping *)a)->data, -2, indent+2,depth-1,flags); break; case T_STRING: { struct pike_string *s=(struct pike_string *)a; fprintf(stderr, "%*s**String length is %ld:\n", indent, "", DO_NOT_WARN((long)s->len)); if(s->len>77) { fprintf(stderr,"%*s** \"%60s ...\"\n",indent,"",s->str); }else{ fprintf(stderr,"%*s** \"%s\"\n",indent,"",s->str); } break; } } } void describe_something(void *a, int t, int indent, int depth, int flags) { int tmp; struct program *p=(struct program *)a; if(!a) return; if(t==-1) { fprintf(stderr,"%*s**Location description: %s\n",indent,"",(char *)a); return; } /* Disable debug, this may help reduce recursion bugs */ tmp=d_flag; d_flag=0; #ifdef DEBUG_MALLOC if (((int)a) == 0x55555555) { fprintf(stderr,"%*s**Location: %p Type: %s Zapped pointer\n",indent,"",a, get_name_of_type(t)); } else #endif /* DEBUG_MALLOC */ if (((ptrdiff_t)a) & 3) { fprintf(stderr,"%*s**Location: %p Type: %s Misaligned address\n",indent,"",a, get_name_of_type(t)); } else { fprintf(stderr,"%*s**Location: %p Type: %s Refs: %d\n",indent,"",a, get_name_of_type(t), *(INT32 *)a); } #ifdef DEBUG_MALLOC if(!(flags & DESCRIBE_NO_DMALLOC)) debug_malloc_dump_references(a,indent+2,depth-1,flags); #endif low_describe_something(a,t,indent,depth,flags); fprintf(stderr,"%*s*******************\n",indent,""); d_flag=tmp; } PMOD_EXPORT void describe(void *x) { describe_something(x, attempt_to_identify(x), 0, 2, 0); } void debug_describe_svalue(struct svalue *s) { fprintf(stderr,"Svalue at %p is:\n",s); switch(s->type) { case T_INT: fprintf(stderr," %ld\n",(long)s->u.integer); break; case T_FLOAT: fprintf(stderr," %f\n",s->u.float_number); break; case T_FUNCTION: if(s->subtype == FUNCTION_BUILTIN) { fprintf(stderr," Builtin function: %s\n",s->u.efun->name->str); }else{ if(!s->u.object->prog) { struct program *p=id_to_program(s->u.object->program_id); if(p) { fprintf(stderr," Function (destructed) name: %s\n",ID_FROM_INT(p,s->subtype)->name->str); }else{ fprintf(stderr," Function in destructed object.\n"); } }else{ fprintf(stderr," Function name: %s\n",ID_FROM_INT(s->u.object->prog,s->subtype)->name->str); } } } describe_something(s->u.refs,s->type,0,2,0); } void debug_gc_touch(void *a) { struct marker *m; if (!a) fatal("Got null pointer.\n"); m = find_marker(a); if (Pike_in_gc == GC_PASS_PRETOUCH) { if (m) gc_fatal(a, 0, "Object touched twice.\n"); get_marker(a)->flags |= GC_TOUCHED; } else if (Pike_in_gc == GC_PASS_POSTTOUCH) { if (!*(INT32 *) a) gc_fatal(a, 1, "Found a thing without refs.\n"); if (m) { if (!(m->flags & GC_TOUCHED)) gc_fatal(a, 2, "An existing but untouched marker found " "for object in linked lists.\n"); else if (m->flags & GC_LIVE_RECURSE || (m->frame && m->frame->frameflags & (GC_WEAK_REF|GC_STRONG_REF))) gc_fatal(a, 2, "Thing still got flag from recurse list.\n"); else if (m->flags & GC_MARKED) return; else if (!(m->flags & GC_NOT_REFERENCED) || m->flags & GC_XREFERENCED) gc_fatal(a, 3, "A thing with external references " "got missed by mark pass.\n"); else if (!(m->flags & GC_CYCLE_CHECKED)) gc_fatal(a, 2, "A thing was missed by " "both mark and cycle check pass.\n"); else if (!(m->flags & GC_IS_REFERENCED)) gc_fatal(a, 2, "An unreferenced thing " "got missed by gc_is_referenced().\n"); else if (!(m->flags & GC_DO_FREE)) gc_fatal(a, 2, "An unreferenced thing " "got missed by gc_do_free().\n"); else if (m->flags & GC_GOT_EXTRA_REF) gc_fatal(a, 2, "A thing still got an extra ref.\n"); else if (m->weak_refs == -1) gc_fatal(a, 3, "A thing which had only weak references is " "still around after gc.\n"); else if (!(m->flags & GC_LIVE)) { if (m->weak_refs > 0) gc_fatal(a, 3, "A thing to garb is still around. " "It's probably one with only external weak refs.\n"); else gc_fatal(a, 3, "A thing to garb is still around.\n"); } } } else fatal("debug_gc_touch() used in invalid gc pass.\n"); } static INLINE struct marker *gc_check_debug(void *a, int weak) { struct marker *m; if (!a) fatal("Got null pointer.\n"); if(check_for) { if(check_for == a) { gdb_gc_stop_here(a, weak); } return 0; } if (Pike_in_gc != GC_PASS_CHECK) fatal("gc check attempted in invalid pass.\n"); m = get_marker(a); if (!*(INT32 *)a) gc_fatal(a, 1, "GC check on thing without refs.\n"); if (m->saved_refs != -1 && m->saved_refs != *(INT32 *)a) gc_fatal(a, 1, "Refs changed in gc check pass.\n"); m->saved_refs = *(INT32 *)a; if (m->refs + m->xrefs >= *(INT32 *) a) /* m->refs will be incremented by the caller. */ gc_fatal(a, 1, "Thing is getting more internal refs than refs.\n"); checked++; return m; } #endif /* PIKE_DEBUG */ INT32 real_gc_check(void *a) { struct marker *m; INT32 ret; #ifdef PIKE_DEBUG if (!(m = gc_check_debug(a, 0))) return 0; #else m = get_marker(a); #endif ret = add_ref(m); if (m->refs >= *(INT32 *) a) m->flags |= GC_NOT_REFERENCED; return ret; } INT32 real_gc_check_weak(void *a) { struct marker *m; INT32 ret; #ifdef PIKE_DEBUG if (!(m = gc_check_debug(a, 1))) return 0; if (m->weak_refs == -1) gc_fatal(a, 1, "Thing has already reached threshold for weak free.\n"); if (m->weak_refs >= *(INT32 *) a) gc_fatal(a, 1, "Thing has gotten more weak refs than refs.\n"); if (m->weak_refs > m->refs + 1) gc_fatal(a, 1, "Thing has gotten more weak refs than internal refs.\n"); #else m = get_marker(a); #endif m->weak_refs++; gc_ext_weak_refs++; if (m->weak_refs >= *(INT32 *) a) m->weak_refs = -1; ret = add_ref(m); if (m->refs >= *(INT32 *) a) m->flags |= GC_NOT_REFERENCED; return ret; } static void init_gc(void) { init_marker_hash(); get_marker(rec_list.data); /* Used to simplify fencepost conditions. */ } static void exit_gc(void) { #ifdef DO_PIKE_CLEANUP int e=0; struct marker *h; for(e=0;e<marker_hash_table_size;e++) while(marker_hash_table[e]) remove_marker(marker_hash_table[e]->data); #endif exit_marker_hash(); free_all_gc_frame_blocks(); #ifdef GC_VERBOSE num_gc_frames = 0; #endif } #ifdef PIKE_DEBUG void locate_references(void *a) { int tmp, orig_in_gc = Pike_in_gc; void *orig_check_for=check_for; if(!Pike_in_gc) init_gc(); Pike_in_gc = GC_PASS_LOCATE; /* Disable debug, this may help reduce recursion bugs */ tmp=d_flag; d_flag=0; fprintf(stderr,"**Looking for references:\n"); check_for=a; found_where=" in an array"; gc_check_all_arrays(); found_where=" in a multiset"; gc_check_all_multisets(); found_where=" in a mapping"; gc_check_all_mappings(); found_where=" in a program"; gc_check_all_programs(); found_where=" in an object"; gc_check_all_objects(); #ifdef PIKE_DEBUG if(master_object) gc_external_mark2(master_object,0," &master_object"); { extern struct mapping *builtin_constants; if(builtin_constants) gc_external_mark2(builtin_constants,0," &builtin_constants"); } #endif found_where=" in a module"; call_callback(& gc_callbacks, (void *)0); found_where=""; check_for=orig_check_for; #ifdef DEBUG_MALLOC { extern void dmalloc_find_references_to(void *); #if 0 fprintf(stderr,"**DMALLOC Looking for references:\n"); dmalloc_find_references_to(a); #endif } #endif Pike_in_gc = orig_in_gc; if(!Pike_in_gc) exit_gc(); d_flag=tmp; } #endif #ifdef PIKE_DEBUG void gc_add_extra_ref(void *a) { struct marker *m = get_marker(a); if (m->flags & GC_GOT_EXTRA_REF) gc_fatal(a, 0, "Thing already got an extra gc ref.\n"); m->flags |= GC_GOT_EXTRA_REF; gc_extra_refs++; ++*(INT32 *) a; } void gc_free_extra_ref(void *a) { struct marker *m = get_marker(a); if (!(m->flags & GC_GOT_EXTRA_REF)) gc_fatal(a, 0, "Thing haven't got an extra gc ref.\n"); m->flags &= ~GC_GOT_EXTRA_REF; gc_extra_refs--; } int debug_gc_is_referenced(void *a) { struct marker *m; if (!a) fatal("Got null pointer.\n"); if (Pike_in_gc != GC_PASS_MARK) fatal("gc_is_referenced() called in invalid gc pass.\n"); if (gc_debug) { m = find_marker(a); if ((!m || !(m->flags & GC_TOUCHED)) && !safe_debug_findstring((struct pike_string *) a)) gc_fatal(a, 0, "Doing gc_is_referenced() on invalid object.\n"); if (!m) m = get_marker(a); } else m = get_marker(a); if (m->flags & GC_IS_REFERENCED) gc_fatal(a, 0, "gc_is_referenced() called twice for thing.\n"); m->flags |= GC_IS_REFERENCED; return !(m->flags & GC_NOT_REFERENCED); } int gc_external_mark3(void *a, void *in, char *where) { struct marker *m; if (!a) fatal("Got null pointer.\n"); if (Pike_in_gc != GC_PASS_CHECK && Pike_in_gc != GC_PASS_LOCATE) fatal("gc_external_mark() called in invalid gc pass.\n"); if(check_for) { if(a==check_for) { char *tmp=found_where; void *tmp2=found_in; if(where) found_where=where; if(in) found_in=in; gdb_gc_stop_here(a, 0); found_where=tmp; found_in=tmp2; return 1; } return 0; } m=get_marker(a); m->xrefs++; m->flags|=GC_XREFERENCED; if(Pike_in_gc == GC_PASS_CHECK && (m->refs + m->xrefs > *(INT32 *)a || (m->saved_refs != -1 && m->saved_refs != *(INT32 *)a))) gc_fatal(a, 1, "Ref counts are wrong.\n"); return 0; } void debug_really_free_gc_frame(struct gc_frame *l) { if (l->frameflags & GC_LINK_FREED) gc_fatal(l->data, 0, "Freeing freed gc_frame.\n"); l->frameflags |= GC_LINK_FREED; l->back = PREV(l) = NEXT(l) = (struct gc_frame *)(ptrdiff_t) -1; really_free_gc_frame(l); #ifdef GC_VERBOSE num_gc_frames--; #endif } #else /* PIKE_DEBUG */ #define debug_really_free_gc_frame(l) really_free_gc_frame(l) #endif /* PIKE_DEBUG */ int gc_do_weak_free(void *a) { struct marker *m; #ifdef PIKE_DEBUG if (!a) fatal("Got null pointer.\n"); if (Pike_in_gc != GC_PASS_MARK && Pike_in_gc != GC_PASS_CYCLE && Pike_in_gc != GC_PASS_ZAP_WEAK) fatal("gc_do_weak_free() called in invalid gc pass.\n"); if (gc_debug) { if (!(m = find_marker(a))) gc_fatal(a, 0, "gc_do_weak_free() got unknown object.\n"); } else m = get_marker(a); debug_malloc_touch(a); if (m->weak_refs > m->refs) gc_fatal(a, 0, "More weak references than internal references.\n"); #else m = get_marker(a); #endif if (Pike_in_gc != GC_PASS_ZAP_WEAK) { if (m->weak_refs == -1) { gc_ext_weak_refs--; return 1; } } else if (!(m->flags & GC_MARKED)) { #ifdef PIKE_DEBUG if (m->weak_refs <= 0) gc_fatal(a, 0, "Too many weak refs cleared to thing with external " "weak refs.\n"); #endif m->weak_refs--; gc_ext_weak_refs--; return 1; } return 0; } int gc_mark(void *a) { struct marker *m = get_marker(debug_malloc_pass(a)); #ifdef PIKE_DEBUG if (!a) fatal("Got null pointer.\n"); if (Pike_in_gc != GC_PASS_MARK && Pike_in_gc != GC_PASS_ZAP_WEAK) fatal("gc mark attempted in invalid pass.\n"); if (!*(INT32 *) a) gc_fatal(a, 0, "Marked a thing without refs.\n"); if (m->weak_refs == -1) gc_fatal(a, 0, "Marking thing scheduled for weak free.\n"); if (Pike_in_gc == GC_PASS_ZAP_WEAK && !(m->flags & GC_MARKED)) gc_fatal(a, 0, "gc_mark() called for thing in zap weak pass " "that wasn't marked before.\n"); #endif if (Pike_in_gc == GC_PASS_ZAP_WEAK) /* Things are visited in the zap weak pass through the mark * functions to free refs to internal things that only got weak * external references. That happens only when a thing also have * internal cyclic non-weak refs. */ if (m->flags & GC_FREE_VISITED) return 0; else { m->flags |= GC_FREE_VISITED; return 1; } else if (m->flags & GC_MARKED) { #ifdef PIKE_DEBUG if (m->weak_refs != 0) gc_fatal(a, 0, "weak_refs changed in marker already visited by gc_mark().\n"); #endif return 0; } else { if (m->weak_refs) { gc_ext_weak_refs -= m->weak_refs; m->weak_refs = 0; } m->flags = (m->flags & ~GC_NOT_REFERENCED) | GC_MARKED; DO_IF_DEBUG(marked++); return 1; } } void gc_cycle_enqueue(gc_cycle_check_cb *checkfn, void *data, int weak) { struct gc_frame *l = alloc_gc_frame(); #ifdef GC_VERBOSE if (++num_gc_frames > max_gc_frames) max_gc_frames = num_gc_frames; #endif l->data = data; l->u.link.checkfn = checkfn; l->u.link.weak = weak; l->frameflags = 0; l->back = gc_rec_top; #ifdef GC_STACK_DEBUG fprintf(stderr, "enqueue %p [%p]: ", l, gc_rec_top); describe_gc_frame(l); fputc('\n', stderr); #endif gc_rec_top = l; } static struct gc_frame *gc_cycle_enqueue_pop(void *data) { struct gc_frame *l = alloc_gc_frame(); #ifdef GC_VERBOSE if (++num_gc_frames > max_gc_frames) max_gc_frames = num_gc_frames; #endif l->data = data; PREV(l) = gc_rec_last; NEXT(l) = 0; CYCLE(l) = 0; l->frameflags = GC_POP_FRAME; l->back = gc_rec_top; #ifdef GC_STACK_DEBUG fprintf(stderr, "enqueue %p [%p]: ", l, gc_rec_top); describe_gc_frame(l); fputc('\n', stderr); #endif gc_rec_top = l; return l; } void gc_cycle_run_queue() { while (gc_rec_top) { #ifdef GC_STACK_DEBUG fprintf(stderr, "dequeue %p [%p]: ", gc_rec_top, gc_rec_top->back); describe_gc_frame(gc_rec_top); fputc('\n', stderr); #endif if (gc_rec_top->frameflags & GC_POP_FRAME) { struct gc_frame *l = gc_rec_top->back; gc_cycle_pop(gc_rec_top->data); gc_rec_top = l; } else { struct gc_frame l = *gc_rec_top; #ifdef PIKE_DEBUG if (l.frameflags & GC_LINK_FREED) gc_fatal(l.data, 0, "Accessing freed gc_frame.\n"); #endif debug_really_free_gc_frame(gc_rec_top); gc_rec_top = l.back; l.u.link.checkfn(l.data, l.u.link.weak); } } } #ifdef GC_CYCLE_DEBUG static int gc_cycle_indent = 0; #define CYCLE_DEBUG_MSG(M, TXT) do { \ fprintf(stderr, "%*s%-35s %p [%p] ", gc_cycle_indent, "", \ (TXT), (M) ? (M)->data : 0, gc_rec_last->data); \ describe_marker(M); \ } while (0) #else #define CYCLE_DEBUG_MSG(M, TXT) do {} while (0) #endif static void rotate_rec_list (struct gc_frame *beg, struct gc_frame *pos) /* Rotates the marker list and the cycle stack so the bit from pos * down to the end gets before the bit from beg down to pos. */ { struct gc_frame *l; #ifdef PIKE_DEBUG CHECK_POP_FRAME(beg); CHECK_POP_FRAME(pos); if (beg == pos) gc_fatal(beg->data, 0, "Cycle already broken at requested position.\n"); if (NEXT(gc_rec_last)) gc_fatal(gc_rec_last->data, 0, "gc_rec_last not at end.\n"); #endif #ifdef GC_STACK_DEBUG fprintf(stderr,"Stack before:\n"); for (l = gc_rec_top; l; l = l->back) { fprintf(stderr, " %p ", l); describe_gc_frame(l); fputc('\n', stderr); } #endif if (CYCLE(beg)) { for (l = beg; CYCLE(PREV(l)) == CYCLE(beg); l = PREV(l)) CHECK_POP_FRAME(l); CHECK_POP_FRAME(l); if (CYCLE(l) == CYCLE(pos)) { /* Breaking something previously marked as a cycle. Clear it * since we're no longer sure it's an ambigious cycle. */ unsigned cycle = CYCLE(l); for (; l && CYCLE(l) == cycle; l = NEXT(l)) { CHECK_POP_FRAME(l); #ifdef GC_CYCLE_DEBUG if (CYCLE(l)) CYCLE_DEBUG_MSG(find_marker(l->data), "> rotate_rec_list, clear cycle"); #endif CYCLE(l) = 0; } } else beg = l; /* Keep the cycle continuous. */ } CYCLE_DEBUG_MSG(find_marker(beg->data), "> rotate_rec_list, begin at"); { struct gc_frame *b = beg, *p = pos, *old_rec_top; while (b->frameflags & GC_OFF_STACK) { if ((b = NEXT(b)) == pos) goto done; CHECK_POP_FRAME(b); } while (p->frameflags & GC_OFF_STACK) { if (!(p = NEXT(p))) goto done; CHECK_POP_FRAME(p); } old_rec_top = gc_rec_top; gc_rec_top = p->back; p->back = b->back; b->back = old_rec_top; } done: { struct gc_frame *new_rec_last = PREV(pos); NEXT(PREV(beg)) = pos; PREV(pos) = PREV(beg); NEXT(gc_rec_last) = beg; PREV(beg) = gc_rec_last; gc_rec_last = new_rec_last; NEXT(gc_rec_last) = 0; } if (beg->frameflags & GC_WEAK_REF) { beg->frameflags &= ~GC_WEAK_REF; pos->frameflags |= GC_WEAK_REF; CYCLE_DEBUG_MSG(get_marker(pos->data), "> rotate_rec_list, moved weak flag"); } #ifdef GC_STACK_DEBUG fprintf(stderr,"Stack after:\n"); for (l = gc_rec_top; l; l = l->back) { fprintf(stderr, " %p ", l); describe_gc_frame(l); fputc('\n', stderr); } #endif } int gc_cycle_push(void *x, struct marker *m, int weak) { struct marker *last = find_marker(gc_rec_last->data); #ifdef PIKE_DEBUG if (!x) fatal("Got null pointer.\n"); if (m->data != x) fatal("Got wrong marker.\n"); if (Pike_in_gc != GC_PASS_CYCLE) fatal("GC cycle push attempted in invalid pass.\n"); if (gc_debug && !(m->flags & GC_TOUCHED)) gc_fatal(x, 0, "gc_cycle_push() called for untouched thing.\n"); if ((!(m->flags & GC_NOT_REFERENCED) || m->flags & GC_MARKED) && *(INT32 *) x) gc_fatal(x, 1, "Got a referenced marker to gc_cycle_push.\n"); if (m->flags & GC_XREFERENCED) gc_fatal(x, 1, "Doing cycle check in externally referenced thing " "missed in mark pass.\n"); if (gc_debug) { struct array *a; struct object *o; struct program *p; struct mapping *m; struct multiset *l; for(a = gc_internal_array; a != &empty_array; a = a->next) if(a == (struct array *) x) goto on_gc_internal_lists; for(o = gc_internal_object; o; o = o->next) if(o == (struct object *) x) goto on_gc_internal_lists; for(p = gc_internal_program; p; p = p->next) if(p == (struct program *) x) goto on_gc_internal_lists; for(m = gc_internal_mapping; m; m = m->next) if(m == (struct mapping *) x) goto on_gc_internal_lists; for(l = gc_internal_multiset; l; l = l->next) if(l == (struct multiset *) x) goto on_gc_internal_lists; gc_fatal(x, 0, "gc_cycle_check() called for thing not on gc_internal lists.\n"); on_gc_internal_lists: ; /* We must have a least one expression after a label! - Hubbe */ } #endif if (last->flags & GC_LIVE_RECURSE) { #ifdef PIKE_DEBUG if (!(last->flags & GC_LIVE)) gc_fatal(x, 0, "Doing live recursion from a dead thing.\n"); #endif if (m->flags & GC_CYCLE_CHECKED) { if (!(m->flags & GC_LIVE)) { /* Only recurse through things already handled; we'll get to the * other later in the normal recursion. */ #ifdef PIKE_DEBUG if (m->flags & GC_LIVE_RECURSE) gc_fatal(x, 0, "Mark live recursion attempted twice into thing.\n"); #endif goto live_recurse; } CYCLE_DEBUG_MSG(m, "gc_cycle_push, no live recurse"); } else { /* Nothing more to do. Unwind the live recursion. */ int flags; CYCLE_DEBUG_MSG(m, "gc_cycle_push, live rec done"); do { last->flags &= ~GC_LIVE_RECURSE; #ifdef GC_CYCLE_DEBUG gc_cycle_indent -= 2; CYCLE_DEBUG_MSG(find_marker(gc_rec_last->data), "> gc_cycle_push, unwinding live"); #endif while (1) { struct gc_frame *l = gc_rec_top; #ifdef PIKE_DEBUG if (!gc_rec_top) fatal("Expected a gc_cycle_pop entry in gc_rec_top.\n"); #endif gc_rec_top = l->back; if (l->frameflags & GC_POP_FRAME) { gc_rec_last = PREV(l); debug_really_free_gc_frame(l); break; } debug_really_free_gc_frame(l); } last = find_marker(gc_rec_last->data); } while (last->flags & GC_LIVE_RECURSE); } return 0; } #ifdef PIKE_DEBUG if (weak < 0 && gc_rec_last->frameflags & GC_FOLLOWED_NONSTRONG) gc_fatal(x, 0, "Followed strong link too late.\n"); if (weak >= 0) gc_rec_last->frameflags |= GC_FOLLOWED_NONSTRONG; #endif if (weak > 0) { #ifdef PIKE_DEBUG if (m->weak_refs <= 0) gc_fatal(x, 0, "Followed weak ref to thing that should have none left.\n"); m->weak_refs--; #endif gc_ext_weak_refs--; } if (m->frame && !(m->frame->frameflags & GC_OFF_STACK)) { /* A cyclic reference is found. */ #ifdef PIKE_DEBUG if (gc_rec_last == &rec_list) gc_fatal(x, 0, "Cyclic ref involves dummy rec_list marker.\n"); CHECK_POP_FRAME(gc_rec_last); CHECK_POP_FRAME(m->frame); #endif if (m != last) { struct gc_frame *p, *weak_ref = 0, *nonstrong_ref = 0; if (!weak) { struct gc_frame *q; CYCLE_DEBUG_MSG(m, "gc_cycle_push, search normal"); for (q = m->frame, p = NEXT(q);; q = p, p = NEXT(p)) { CHECK_POP_FRAME(p); if (p->frameflags & (GC_WEAK_REF|GC_STRONG_REF)) { if (p->frameflags & GC_WEAK_REF) weak_ref = p; else if (!nonstrong_ref) nonstrong_ref = q; } if (p == gc_rec_last) break; } } else if (weak < 0) { CYCLE_DEBUG_MSG(m, "gc_cycle_push, search strong"); for (p = NEXT(m->frame);; p = NEXT(p)) { CHECK_POP_FRAME(p); if (p->frameflags & GC_WEAK_REF) weak_ref = p; if (!(p->frameflags & GC_STRONG_REF)) nonstrong_ref = p; if (p == gc_rec_last) break; } #ifdef PIKE_DEBUG if (p == gc_rec_last && !nonstrong_ref) gc_fatal(x, 0, "Only strong links in cycle.\n"); #endif } else { struct gc_frame *q; CYCLE_DEBUG_MSG(m, "gc_cycle_push, search weak"); for (q = m->frame, p = NEXT(q);; q = p, p = NEXT(p)) { CHECK_POP_FRAME(p); if (!(p->frameflags & GC_WEAK_REF) && !nonstrong_ref) nonstrong_ref = q; if (p == gc_rec_last) break; } } if (weak_ref) { /* The backward link is normal or strong and there are one * or more weak links in the cycle. Let's break it at the * last one (to ensure that a sequence of several weak links * are broken at the last one). */ CYCLE_DEBUG_MSG(find_marker(weak_ref->data), "gc_cycle_push, weak break"); rotate_rec_list(m->frame, weak_ref); } else if (weak < 0) { /* The backward link is strong. Must break the cycle at the * last nonstrong link. */ if (m->frame->frameflags & GC_STRONG_REF) nonstrong_ref->frameflags = (nonstrong_ref->frameflags & ~GC_WEAK_REF) | GC_STRONG_REF; else m->frame->frameflags = (m->frame->frameflags & ~GC_WEAK_REF) | GC_STRONG_REF; CYCLE_DEBUG_MSG(find_marker(nonstrong_ref->data), "gc_cycle_push, nonstrong break"); rotate_rec_list(m->frame, nonstrong_ref); } else if (nonstrong_ref) { /* Either a nonweak cycle with a strong link in it or a weak * cycle with a nonweak link in it. Break before the first * link that's stronger than the others. */ if (nonstrong_ref != m->frame) { CYCLE_DEBUG_MSG(find_marker(nonstrong_ref->data), "gc_cycle_push, weaker break"); rotate_rec_list(m->frame, nonstrong_ref); } } else if (!weak) { /* A normal cycle which will be destructed in arbitrary * order. For reasons having to do with strong links we * can't mark weak cycles this way. */ unsigned cycle = CYCLE(m->frame) ? CYCLE(m->frame) : ++last_cycle; if (cycle == CYCLE(gc_rec_last)) CYCLE_DEBUG_MSG(m, "gc_cycle_push, old cycle"); else { CYCLE_DEBUG_MSG(m, "gc_cycle_push, cycle"); for (p = m->frame;; p = NEXT(p)) { CYCLE(p) = cycle; CYCLE_DEBUG_MSG(find_marker(p->data), "> gc_cycle_push, mark cycle"); if (p == gc_rec_last) break; }}}}} /* Mmm.. lisp ;) */ else if (!(m->flags & GC_CYCLE_CHECKED)) { struct gc_frame *l, *prev_rec_last = gc_rec_last; #ifdef PIKE_DEBUG cycle_checked++; if (m->frame) gc_fatal(x, 0, "Marker already got a frame.\n"); if (NEXT(gc_rec_last)) gc_fatal(gc_rec_last->data, 0, "Not at end of list.\n"); #endif NEXT(gc_rec_last) = m->frame = l = gc_cycle_enqueue_pop(x); m->flags |= GC_CYCLE_CHECKED | (last->flags & GC_LIVE); if (weak) { if (weak > 0) l->frameflags |= GC_WEAK_REF; else l->frameflags |= GC_STRONG_REF; } #ifdef GC_CYCLE_DEBUG if (weak > 0) CYCLE_DEBUG_MSG(m, "gc_cycle_push, recurse weak"); else if (weak < 0) CYCLE_DEBUG_MSG(m, "gc_cycle_push, recurse strong"); else CYCLE_DEBUG_MSG(m, "gc_cycle_push, recurse"); gc_cycle_indent += 2; #endif gc_rec_last = l; return 1; } /* Should normally not recurse now, but got to do that anyway if we * must mark live things. */ if (!(last->flags & GC_LIVE) || m->flags & GC_LIVE) { CYCLE_DEBUG_MSG(m, "gc_cycle_push, no recurse"); return 0; } live_recurse: #ifdef PIKE_DEBUG if (m->flags & GC_LIVE) fatal("Shouldn't live recurse when there's nothing to do.\n"); #endif m->flags |= GC_LIVE|GC_LIVE_RECURSE; if (m->flags & GC_GOT_DEAD_REF) { /* A thing previously popped as dead is now being marked live. * Have to remove the extra ref added by gc_cycle_pop(). */ gc_free_extra_ref(x); if (!--*(INT32 *) x) { #ifdef PIKE_DEBUG gc_fatal(x, 0, "Thing got zero refs after removing the dead gc ref.\n"); #endif } } { /* Recurse without linking onto rec_list. */ struct gc_frame *l = gc_cycle_enqueue_pop(x); #ifdef GC_CYCLE_DEBUG CYCLE_DEBUG_MSG(m, "gc_cycle_push, live recurse"); gc_cycle_indent += 2; #endif gc_rec_last = l; } return 1; } static void gc_cycle_pop(void *a) { struct marker *m = find_marker(a); struct gc_frame *here, *base, *p; #ifdef PIKE_DEBUG if (!a) fatal("Got null pointer.\n"); if (Pike_in_gc != GC_PASS_CYCLE) fatal("GC cycle pop attempted in invalid pass.\n"); if (!(m->flags & GC_CYCLE_CHECKED)) gc_fatal(a, 0, "Marker being popped doesn't have GC_CYCLE_CHECKED.\n"); if ((!(m->flags & GC_NOT_REFERENCED) || m->flags & GC_MARKED) && *(INT32 *) a) gc_fatal(a, 1, "Got a referenced marker to gc_cycle_pop.\n"); if (m->flags & GC_XREFERENCED) gc_fatal(a, 1, "Doing cycle check in externally referenced thing " "missed in mark pass.\n"); #endif #ifdef GC_CYCLE_DEBUG gc_cycle_indent -= 2; #endif if (m->flags & GC_LIVE_RECURSE) { m->flags &= ~GC_LIVE_RECURSE; CYCLE_DEBUG_MSG(m, "gc_cycle_pop_live"); gc_rec_last = PREV(gc_rec_top); debug_really_free_gc_frame(gc_rec_top); return; } here = m->frame; #ifdef PIKE_DEBUG if (!here || here->data != a) gc_fatal(a, 0, "Marker being popped has no or invalid frame.\n"); CHECK_POP_FRAME(here); CHECK_POP_FRAME(gc_rec_last); if (here->frameflags & GC_OFF_STACK) gc_fatal(a, 0, "Marker being popped isn't on stack.\n"); here->back = (struct gc_frame *)(ptrdiff_t) -1; #endif here->frameflags |= GC_OFF_STACK; for (base = PREV(here), p = here;; base = p, p = NEXT(p)) { if (base == here) { /* Part of a cycle; wait until the cycle is complete before * unlinking it from rec_list. */ DO_IF_DEBUG(m->frame->back = (struct gc_frame *)(ptrdiff_t) -1); CYCLE_DEBUG_MSG(m, "gc_cycle_pop, keep cycle"); return; } CHECK_POP_FRAME(p); if (!(CYCLE(p) && CYCLE(p) == CYCLE(base))) break; } gc_rec_last = base; while ((p = NEXT(base))) { struct marker *pm = find_marker(p->data); #ifdef PIKE_DEBUG if (pm->frame != p) gc_fatal(p->data, 0, "Bogus marker for thing being popped.\n"); if (pm->flags & GC_GOT_DEAD_REF) gc_fatal(p->data, 0, "Didn't expect a dead extra ref.\n"); #endif p->frameflags &= ~(GC_WEAK_REF|GC_STRONG_REF); if (pm->flags & GC_LIVE_OBJ) { /* This extra ref is taken away in the kill pass. */ gc_add_extra_ref(p->data); base = p; DO_IF_DEBUG(PREV(p) = (struct gc_frame *)(ptrdiff_t) -1); CYCLE_DEBUG_MSG(pm, "gc_cycle_pop, put on kill list"); } else { if (!(pm->flags & GC_LIVE)) { /* Add an extra ref which is taken away in the free pass. This * is done to not refcount garb the cycles themselves * recursively, which in bad cases can consume a lot of C * stack. */ #ifdef PIKE_DEBUG if (pm->flags & GC_GOT_DEAD_REF) gc_fatal(pm->data, 0, "A thing already got an extra dead cycle ref.\n"); #endif gc_add_extra_ref(pm->data); pm->flags |= GC_GOT_DEAD_REF; } NEXT(base) = NEXT(p); CYCLE_DEBUG_MSG(pm, "gc_cycle_pop, pop off"); pm->frame = 0; debug_really_free_gc_frame(p); } } if (base != gc_rec_last) { NEXT(base) = kill_list; kill_list = NEXT(gc_rec_last); NEXT(gc_rec_last) = 0; } } void do_gc_recurse_svalues(struct svalue *s, int num) { gc_recurse_svalues(s, num); } void do_gc_recurse_short_svalue(union anything *u, TYPE_T type) { gc_recurse_short_svalue(u, type); } int gc_do_free(void *a) { struct marker *m; #ifdef PIKE_DEBUG if (!a) fatal("Got null pointer.\n"); if (Pike_in_gc != GC_PASS_FREE) fatal("gc free attempted in invalid pass.\n"); #endif m=find_marker(debug_malloc_pass(a)); if (!m) return 0; /* Object created after cycle pass. */ #ifdef PIKE_DEBUG if (*(INT32 *) a > !!(m->flags & GC_GOT_EXTRA_REF)) { if (!(m->flags & GC_NOT_REFERENCED) || m->flags & GC_MARKED) gc_fatal(a, 0, "gc_do_free() called for referenced thing.\n"); if (gc_debug && (m->flags & (GC_TOUCHED|GC_MARKED|GC_IS_REFERENCED)) == GC_TOUCHED) gc_fatal(a, 0, "gc_do_free() called without prior call to " "gc_mark() or gc_is_referenced().\n"); } if((m->flags & (GC_MARKED|GC_XREFERENCED)) == GC_XREFERENCED) gc_fatal(a, 1, "Thing with external reference missed in gc mark pass.\n"); if ((m->flags & (GC_DO_FREE|GC_LIVE)) == GC_LIVE) live_ref++; m->flags |= GC_DO_FREE; #endif return !(m->flags & GC_LIVE); } static void warn_bad_cycles() { JMP_BUF uwp; struct array *obj_arr = 0; if (!SETJMP(uwp)) { struct gc_frame *p; unsigned cycle = 0; obj_arr = allocate_array(0); for (p = kill_list; p;) { if ((cycle = CYCLE(p))) { push_object((struct object *) p->data); obj_arr = append_array(obj_arr, --sp); } p = NEXT(p); if (p ? ((unsigned)(CYCLE(p) != cycle)) : cycle) { if (obj_arr->size >= 2) { push_constant_text("gc"); push_constant_text("bad_cycle"); push_array(obj_arr); obj_arr = 0; SAFE_APPLY_MASTER("runtime_warning", 3); pop_stack(); obj_arr = allocate_array(0); } else obj_arr = resize_array(obj_arr, 0); } if (!p) break; } } UNSETJMP(uwp); if (obj_arr) free_array(obj_arr); } int do_gc(void) { double tmp; int objs, pre_kill_objs; double multiplier; struct array *a; struct multiset *l; struct mapping *m; struct program *p; struct object *o; #ifdef PIKE_DEBUG #ifdef HAVE_GETHRTIME hrtime_t gcstarttime = 0; #endif unsigned destroy_count, obj_count; #endif if(Pike_in_gc) return 0; init_gc(); Pike_in_gc=GC_PASS_PREPARE; #ifdef PIKE_DEBUG gc_debug = d_flag; #endif destruct_objects_to_destruct(); if(gc_evaluator_callback) { remove_callback(gc_evaluator_callback); gc_evaluator_callback=0; } objs=num_objects; last_cycle = 0; #ifdef PIKE_DEBUG if(GC_VERBOSE_DO(1 ||) t_flag) { fprintf(stderr,"Garbage collecting ... "); GC_VERBOSE_DO(fprintf(stderr, "\n")); #ifdef HAVE_GETHRTIME gcstarttime = gethrtime(); #endif } if(num_objects < 0) fatal("Panic, less than zero objects!\n"); #endif last_gc=TIME(0); multiplier=pow(MULTIPLIER, (double) num_allocs / (double) alloc_threshold); objects_alloced*=multiplier; objects_alloced += (double) num_allocs; objects_freed*=multiplier; /* Thread switches, object alloc/free and any reference changes * (except by the gc itself) are disallowed now. */ #ifdef PIKE_DEBUG weak_freed = checked = marked = cycle_checked = live_ref = 0; if (gc_debug) { unsigned n; Pike_in_gc = GC_PASS_PRETOUCH; n = gc_touch_all_arrays(); n += gc_touch_all_multisets(); n += gc_touch_all_mappings(); n += gc_touch_all_programs(); n += gc_touch_all_objects(); if (n != (unsigned) num_objects) fatal("Object count wrong before gc; expected %d, got %d.\n", num_objects, n); GC_VERBOSE_DO(fprintf(stderr, "| pretouch: %u things\n", n)); } #endif Pike_in_gc=GC_PASS_CHECK; gc_ext_weak_refs = 0; /* First we count internal references */ gc_check_all_arrays(); gc_check_all_multisets(); gc_check_all_mappings(); gc_check_all_programs(); gc_check_all_objects(); #ifdef PIKE_DEBUG if(master_object) gc_external_mark2(master_object,0," &master_object"); { extern struct mapping *builtin_constants; if(builtin_constants) gc_external_mark2(builtin_constants,0," &builtin_constants"); } #endif /* These callbacks are mainly for the check pass, but can also * do things that are normally associated with the mark pass */ call_callback(& gc_callbacks, (void *)0); GC_VERBOSE_DO(fprintf(stderr, "| check: %u references checked\n", checked)); Pike_in_gc=GC_PASS_MARK; /* Anything after and including gc_internal_foo in the linked lists * are considered to lack external references. The mark pass move * externally referenced things in front of these pointers. */ gc_internal_array = empty_array.next; gc_internal_multiset = first_multiset; gc_internal_mapping = first_mapping; gc_internal_program = first_program; gc_internal_object = first_object; /* Next we mark anything with external references */ gc_mark_all_arrays(); run_queue(&gc_mark_queue); gc_mark_all_multisets(); run_queue(&gc_mark_queue); gc_mark_all_mappings(); run_queue(&gc_mark_queue); gc_mark_all_programs(); run_queue(&gc_mark_queue); gc_mark_all_objects(); run_queue(&gc_mark_queue); /* if(gc_debug) */ /* gc_mark_all_strings(); */ GC_VERBOSE_DO(fprintf(stderr, "| mark: %u markers referenced,\n" "| %u weak references freed, %d things really freed\n", marked, weak_freed, objs - num_objects)); Pike_in_gc=GC_PASS_CYCLE; #ifdef PIKE_DEBUG obj_count = num_objects; max_gc_frames = 0; #endif /* Now find all cycles in the internal structures */ /* Note: The order between types here is normally not significant, * but the permuting destruct order tests in the testsuite won't be * really effective unless objects are handled first. :P */ gc_cycle_check_all_objects(); gc_cycle_check_all_arrays(); gc_cycle_check_all_multisets(); gc_cycle_check_all_mappings(); gc_cycle_check_all_programs(); #ifdef PIKE_DEBUG if (gc_rec_top) fatal("gc_rec_top not empty at end of cycle check pass.\n"); if (NEXT(&rec_list) || gc_rec_last != &rec_list || gc_rec_top) fatal("Recurse list not empty or inconsistent after cycle check pass.\n"); #endif GC_VERBOSE_DO(fprintf(stderr, "| cycle: %u internal things visited, %u cycle ids used,\n" "| %u weak references freed, %d things really freed,\n" "| space for %u gc frames used\n", cycle_checked, last_cycle, weak_freed, obj_count - num_objects, max_gc_frames)); if (gc_ext_weak_refs) { size_t to_free = gc_ext_weak_refs; #ifdef PIKE_DEBUG obj_count = num_objects; #endif Pike_in_gc = GC_PASS_ZAP_WEAK; /* Zap weak references from external to internal things. That * doesn't occur very often; only when something have both * external weak refs and nonweak cyclic refs from internal * things. */ gc_zap_ext_weak_refs_in_arrays(); /* Multisets handled as arrays. */ if (gc_ext_weak_refs) { gc_zap_ext_weak_refs_in_mappings(); if (gc_ext_weak_refs) { gc_zap_ext_weak_refs_in_programs(); if (gc_ext_weak_refs) gc_zap_ext_weak_refs_in_objects(); } } GC_VERBOSE_DO( fprintf(stderr, "| zap weak: freed %u external weak refs, %d things really freed\n", to_free - gc_ext_weak_refs, obj_count - num_objects)); } /* Thread switches, object alloc/free and reference changes are * allowed again now. */ Pike_in_gc=GC_PASS_FREE; #ifdef PIKE_DEBUG weak_freed = 0; obj_count = num_objects; #endif /* Now we free the unused stuff */ gc_free_all_unreferenced_arrays(); gc_free_all_unreferenced_multisets(); gc_free_all_unreferenced_mappings(); gc_free_all_unreferenced_programs(); gc_free_all_unreferenced_objects(); GC_VERBOSE_DO(fprintf(stderr, "| free: %d really freed, %u left with live references\n", obj_count - num_objects, live_ref)); gc_internal_array = &empty_array; gc_internal_multiset = 0; gc_internal_mapping = 0; gc_internal_program = 0; gc_internal_object = 0; #ifdef PIKE_DEBUG if(fatal_after_gc) fatal(fatal_after_gc); #endif Pike_in_gc=GC_PASS_KILL; /* Destruct the live objects in cycles, but first warn about any bad * cycles. */ pre_kill_objs = num_objects; if (last_cycle) { objs -= num_objects; warn_bad_cycles(); objs += num_objects; } #ifdef PIKE_DEBUG destroy_count = 0; #endif while (kill_list) { struct gc_frame *next = NEXT(kill_list); struct object *o = (struct object *) kill_list->data; #ifdef PIKE_DEBUG if ((get_marker(kill_list->data)->flags & (GC_LIVE|GC_LIVE_OBJ)) != (GC_LIVE|GC_LIVE_OBJ)) gc_fatal(o, 0, "Invalid thing in kill list.\n"); if (o->parent && !o->parent->prog && get_marker(o->parent)->flags & GC_LIVE_OBJ) gc_fatal(o, 0, "GC destructed parent prematurely.\n"); #endif GC_VERBOSE_DO(fprintf(stderr, "| Killing %p with %d refs\n", o, o->refs)); destruct(o); free_object(o); gc_free_extra_ref(o); #ifdef PIKE_DEBUG destroy_count++; #endif debug_really_free_gc_frame(kill_list); kill_list = next; } GC_VERBOSE_DO(fprintf(stderr, "| kill: %u objects killed, %d things really freed\n", destroy_count, pre_kill_objs - num_objects)); Pike_in_gc=GC_PASS_DESTRUCT; /* Destruct objects on the destruct queue. */ GC_VERBOSE_DO(obj_count = num_objects); destruct_objects_to_destruct(); GC_VERBOSE_DO(fprintf(stderr, "| destruct: %d things really freed\n", obj_count - num_objects)); #ifdef PIKE_DEBUG if (gc_debug) { unsigned n; Pike_in_gc=GC_PASS_POSTTOUCH; n = gc_touch_all_arrays(); n += gc_touch_all_multisets(); n += gc_touch_all_mappings(); n += gc_touch_all_programs(); n += gc_touch_all_objects(); if (n != (unsigned) num_objects) fatal("Object count wrong after gc; expected %d, got %d.\n", num_objects, n); GC_VERBOSE_DO(fprintf(stderr, "| posttouch: %u things\n", n)); if(fatal_after_gc) fatal(fatal_after_gc); } if (gc_extra_refs) fatal("Lost track of %d extra refs to things in gc.\n", gc_extra_refs); if (gc_ext_weak_refs) fatal("Still got %u external weak references to internal things in gc.\n", gc_ext_weak_refs); #endif Pike_in_gc=0; exit_gc(); /* It's possible that more things got allocated in the kill pass * than were freed. The count before that is a better measurement * then. */ if (pre_kill_objs < num_objects) objs -= pre_kill_objs; else objs -= num_objects; objects_freed += (double) objs; tmp=(double)num_objects; tmp=tmp * GC_CONST/100.0 * (objects_alloced+1.0) / (objects_freed+1.0); if(alloc_threshold + num_allocs <= tmp) tmp = (double)(alloc_threshold + num_allocs); if(tmp < MIN_ALLOC_THRESHOLD) tmp = (double)MIN_ALLOC_THRESHOLD; if(tmp > MAX_ALLOC_THRESHOLD) tmp = (double)MAX_ALLOC_THRESHOLD; alloc_threshold = (ptrdiff_t)tmp; num_allocs=0; #ifdef PIKE_DEBUG if(GC_VERBOSE_DO(1 ||) t_flag) { #ifdef HAVE_GETHRTIME fprintf(stderr,"done (freed %ld of %ld objects), %ld ms.\n", (long)objs,(long)objs + num_objects, (long)((gethrtime() - gcstarttime)/1000000)); #else fprintf(stderr,"done (freed %ld of %ld objects)\n", (long)objs,(long)objs + num_objects); #endif } #endif #ifdef ALWAYS_GC ADD_GC_CALLBACK(); #else if(d_flag > 3) ADD_GC_CALLBACK(); #endif return objs; } void f__gc_status(INT32 args) { pop_n_elems(args); push_constant_text("num_objects"); push_int(num_objects); push_constant_text("num_allocs"); push_int(num_allocs); push_constant_text("alloc_threshold"); push_int64(alloc_threshold); push_constant_text("objects_alloced"); push_int64(objects_alloced); push_constant_text("objects_freed"); push_int64(objects_freed); push_constant_text("last_gc"); push_int64(last_gc); push_constant_text("projected_garbage"); push_float(objects_freed * (double) num_allocs / (double) alloc_threshold); f_aggregate_mapping(14); }

pike.git/ src/ gc.c > e6cce8b4b5bccad1d05ba0be7a0b1992612c5e9e [Annotate]