/*
* Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
* Copyright (c) 1991-1993 by Xerox Corporation. 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 copy this garbage collector for any purpose,
* provided the above notices are retained on all copies.
*/
# ifndef GC←PRIVATE←H
# define GC←PRIVATE←H
# ifndef GC←H
# include "gc.h"
# endif
typedef GC←word word;
typedef GC←signed←word signed←word;
# ifndef CONFIG←H
# include "config.h"
# endif
# ifndef HEADERS←H
# include "gc←headers.h"
# endif
# ifndef bool
typedef int bool;
# endif
# define TRUE 1
# define FALSE 0
typedef char * ptr←t; /* A generic pointer to which we can add */
/* byte displacments. */
#ifdef ←←STDC←←
# if !(defined( sony←news ) )
# include <stddef.h>
# endif
typedef void * extern←ptr←t;
# define VOLATILE volatile
#else
typedef char * extern←ptr←t;
# define VOLATILE
#endif
# ifndef OS2
# include <sys/types.h>
# endif
/*********************************/
/* */
/* Definitions for conservative */
/* collector */
/* */
/*********************************/
/*********************************/
/* */
/* Easily changeable parameters */
/* */
/*********************************/
#define STUBBORN←ALLOC /* Define stubborn allocation primitives */
#define ALL←INTERIOR←POINTERS
/* Forces all pointers into the interior of an */
/* object to be considered valid. Also causes the */
/* sizes of all objects to be inflated by at least */
/* one byte. This should suffice to guarantee */
/* that in the presence of a compiler that does */
/* not perform garbage-collector-unsafe */
/* optimizations, all portable, strictly ANSI */
/* conforming C programs should be safely usable */
/* with malloc replaced by GC←malloc and free */
/* calls removed. There are several disadvantages: */
/* 1. There are probably no interesting, portable, */
/* strictly ANSI conforming C programs. */
/* 2. This option makes it hard for the collector */
/* to allocate space that is not ``pointed to'' */
/* by integers, etc. Under SunOS 4.X with a */
/* statically linked libc, we empiricaly */
/* observed that it would be difficult to */
/* allocate individual objects larger than 100K. */
/* Even if only smaller objects are allocated, */
/* more swap space is likely to be needed. */
/* Fortunately, much of this will never be */
/* touched. */
/* If you can easily avoid using this option, do. */
/* If not, try to keep individual objects small. */
#undef ALL←INTERIOR←POINTERS
#define PRINTSTATS /* Print garbage collection statistics */
/* For less verbose output, undefine in reclaim.c */
#define PRINTTIMES /* Print the amount of time consumed by each garbage */
/* collection. */
#define PRINTBLOCKS /* Print object sizes associated with heap blocks, */
/* whether the objects are atomic or composite, and */
/* whether or not the block was found to be empty */
/* duing the reclaim phase. Typically generates */
/* about one screenful per garbage collection. */
#undef PRINTBLOCKS
#define PRINTBLACKLIST /* Print black listed blocks, i.e. values that */
/* cause the allocator to avoid allocating certain */
/* blocks in order to avoid introducing "false */
/* hits". */
#undef PRINTBLACKLIST
#ifdef SILENT
# ifdef PRINTSTATS
# undef PRINTSTATS
# endif
# ifdef PRINTTIMES
# undef PRINTTIMES
# endif
# ifdef PRINTNBLOCKS
# undef PRINTNBLOCKS
# endif
#endif
#if defined(PRINTSTATS) && !defined(GATHERSTATS)
# define GATHERSTATS
#endif
#ifdef SPARC
# define ALIGN←DOUBLE /* Align objects of size > 1 word on 2 word */
/* boundaries. Wasteful of memory, but */
/* apparently required by SPARC architecture. */
#endif
#if defined(SPARC) || defined(M68K) && defined(SUNOS)
# if !defined(PCR)
# define DYNAMIC←LOADING /* Search dynamic libraries for roots. */
# else
/* PCR handles any dynamic loading whether with dlopen or otherwise */
# endif
#endif
#define MERGE←SIZES /* Round up some object sizes, so that fewer distinct */
/* free lists are actually maintained. This applies */
/* only to the top level routines in misc.c, not to */
/* user generated code that calls GC←allocobj and */
/* GC←allocaobj directly. */
/* Slows down average programs slightly. May however */
/* substantially reduce fragmentation if allocation */
/* request sizes are widely scattered. */
/* May save significant amounts of space for obj←map */
/* entries. */
/* ALIGN←DOUBLE requires MERGE←SIZES at present. */
# if defined(ALIGN←DOUBLE) && !defined(MERGE←SIZES)
# define MERGE←SIZES
# endif
# define HINCR 16 /* Initial heap increment, in blocks of 4K */
# define MAXHINCR 512 /* Maximum heap increment, in blocks */
# define HINCR←MULT 5 /* After each new allocation, GC←hincr is */
# define HINCR←DIV 4 /* multiplied by HINCR←MULT/HINCR←DIV */
# define GC←MULT 3 /* Don't collect if the fraction of */
/* non-collectable memory in the heap */
/* exceeds GC←MUL/GC←DIV */
# define GC←DIV 4
# define NON←GC←HINCR ((word)8)
/* Heap increment if most of heap if collection */
/* was suppressed because most of heap is not */
/* collectable */
/*********************************/
/* */
/* OS interface routines */
/* */
/*********************************/
#include <time.h>
#if !defined(←←STDC←←) && defined(SPARC) && defined(SUNOS4)
clock←t clock(); /* Not in time.h, where it belongs */
#endif
#if !defined(CLOCKS←PER←SEC)
# define CLOCKS←PER←SEC 1000000
/*
* This is technically a bug in the implementation. ANSI requires that
* CLOCKS←PER←SEC be defined. But at least under SunOS4.1.1, it isn't.
* Also note that the combination of ANSI C and POSIX is incredibly gross
* here. The type clock←t is used by both clock() and times(). But on
* some machines thes use different notions of a clock tick, CLOCKS←PER←SEC
* seems to apply only to clock. Hence we use it here. On many machines,
* including SunOS, clock actually uses units of microseconds (which are
* not really clock ticks).
*/
#endif
#define CLOCK←TYPE clock←t
#define GET←TIME(x) x = clock()
#define MS←TIME←DIFF(a,b) ((unsigned long) \
(1000.0*(double)((a)-(b))/(double)CLOCKS←PER←SEC))
/* We use bzero and bcopy internally. They may not be available. */
# if defined(SPARC) && defined(SUNOS4)
# define BCOPY←EXISTS
# endif
# if defined(M68K) && defined(SUNOS)
# define BCOPY←EXISTS
# endif
# if defined(VAX)
# define BCOPY←EXISTS
# endif
# ifndef BCOPY←EXISTS
# include <string.h>
# define bcopy(x,y,n) memcpy(y,x,n)
# define bzero(x,n) memset(x, 0, n)
# endif
/* HBLKSIZE aligned allocation. 0 is taken to mean failure */
/* space is assumed to be cleared. */
# ifdef PCR
char * real←malloc();
# define GET←MEM(bytes) HBLKPTR(real←malloc((size←t)bytes + HBLKSIZE) \
+ HBLKSIZE-1)
# define THREADS
# else
# ifdef OS2
void * os2←alloc(size←t bytes);
# define GET←MEM(bytes) HBLKPTR((ptr←t)os2←alloc((size←t)bytes + HBLKSIZE) \
+ HBLKSIZE-1)
# else
extern ptr←t GC←unix←get←mem();
# define GET←MEM(bytes) (struct hblk *)GC←unix←get←mem(bytes)
# endif
# endif
/*
* Mutual exclusion between allocator/collector routines.
* Needed if there is more than one allocator thread.
* FASTLOCK() is assumed to try to acquire the lock in a cheap and
* dirty way that is acceptable for a few instructions, e.g. by
* inhibiting preemption. This is assumed to have succeeded only
* if a subsequent call to FASTLOCK←SUCCEEDED() returns TRUE.
* FASTUNLOCK() is called whether or not FASTLOCK←SUCCEEDED().
* If signals cannot be tolerated with the FASTLOCK held, then
* FASTLOCK should disable signals. The code executed under
* FASTLOCK is otherwise immune to interruption, provided it is
* not restarted.
* DCL←LOCK←STATE declares any local variables needed by LOCK and UNLOCK
* and/or DISABLE←SIGNALS and ENABLE←SIGNALS and/or FASTLOCK.
* (There is currently no equivalent for FASTLOCK.)
*/
# ifdef PCR
# include "th/PCR←Th.h"
# include "th/PCR←ThCrSec.h"
extern struct PCR←Th←MLRep GC←allocate←ml;
# define DCL←LOCK←STATE PCR←sigset←t GC←old←sig←mask
# define LOCK() PCR←Th←ML←Acquire(&GC←allocate←ml)
# define UNLOCK() PCR←Th←ML←Release(&GC←allocate←ml)
# define FASTLOCK() PCR←ThCrSec←EnterSys()
/* Here we cheat (a lot): */
# define FASTLOCK←SUCCEEDED() (*(int *)(&GC←allocate←ml) == 0)
/* TRUE if nobody currently holds the lock */
# define FASTUNLOCK() PCR←ThCrSec←ExitSys()
# else
# define DCL←LOCK←STATE
# define LOCK()
# define UNLOCK()
# define FASTLOCK() LOCK()
# define FASTLOCK←SUCCEEDED() TRUE
# define FASTUNLOCK() UNLOCK()
# endif
/* Delay any interrupts or signals that may abort this thread. Data */
/* structures are in a consistent state outside this pair of calls. */
/* ANSI C allows both to be empty (though the standard isn't very */
/* clear on that point). Standard malloc implementations are usually */
/* neither interruptable nor thread-safe, and thus correspond to */
/* empty definitions. */
# ifdef PCR
# define DISABLE←SIGNALS() \
PCR←Th←SetSigMask(PCR←allSigsBlocked,&GC←old←sig←mask)
# define ENABLE←SIGNALS() \
PCR←Th←SetSigMask(&GC←old←sig←mask, NIL)
# else
# if 0 /* Useful for debugging, and unusually */
/* correct client code. */
# define DISABLE←SIGNALS()
# define ENABLE←SIGNALS()
# else
# define DISABLE←SIGNALS() GC←disable←signals()
void GC←disable←signals();
# define ENABLE←SIGNALS() GC←enable←signals()
void GC←enable←signals();
# endif
# endif
/*
* Stop and restart mutator threads.
*/
# ifdef PCR
# include "th/PCR←ThCtl.h"
# define STOP←WORLD() \
PCR←ThCtl←SetExclusiveMode(PCR←ThCtl←ExclusiveMode←stopNormal, \
PCR←allSigsBlocked, \
PCR←waitForever)
# define START←WORLD() \
PCR←ThCtl←SetExclusiveMode(PCR←ThCtl←ExclusiveMode←null, \
PCR←allSigsBlocked, \
PCR←waitForever);
# else
# define STOP←WORLD()
# define START←WORLD()
# endif
/* Abandon ship */
# ifdef PCR
void PCR←Base←Panic(const char *fmt, ...);
# define ABORT(s) PCR←Base←Panic(s)
# else
# define ABORT(s) abort(s)
# endif
/* Exit abnormally, but without making a mess (e.g. out of memory) */
# ifdef PCR
void PCR←Base←Exit(int status);
# define EXIT() PCR←Base←Exit(1)
# else
# define EXIT() (void)exit(1)
# endif
/* Print warning message, e.g. almost out of memory. */
# define WARN(s) GC←printf0(s)
/*********************************/
/* */
/* Word-size-dependent defines */
/* */
/*********************************/
#if CPP←WORDSZ == 32
# define WORDS←TO←BYTES(x) ((x)<<2)
# define BYTES←TO←WORDS(x) ((x)>>2)
# define LOGWL ((word)5) /* log[2] of CPP←WORDSZ */
# define modWORDSZ(n) ((n) & 0x1f) /* n mod size of word */
#endif
#if CPP←WORDSZ == 64
# define WORDS←TO←BYTES(x) ((x)<<3)
# define BYTES←TO←WORDS(x) ((x)>>3)
# define LOGWL ((word)6) /* log[2] of CPP←WORDSZ */
# define modWORDSZ(n) ((n) & 0x3f) /* n mod size of word */
#endif
#define WORDSZ ((word)CPP←WORDSZ)
#define SIGNB ((word)1 << (WORDSZ-1))
#define BYTES←PER←WORD ((word)(sizeof (word)))
#define ONES ((word)(-1))
#define divWORDSZ(n) ((n) >> LOGWL) /* divide n by size of word */
/*********************/
/* */
/* Size Parameters */
/* */
/*********************/
/* heap block size, bytes. Should be power of 2 */
#if CPP←WORDSZ == 32
# define CPP←LOG←HBLKSIZE 12
#else
# define CPP←LOG←HBLKSIZE 13
#endif
#define LOG←HBLKSIZE ((word)CPP←LOG←HBLKSIZE)
#define CPP←HBLKSIZE (1 << CPP←LOG←HBLKSIZE)
#define HBLKSIZE ((word)CPP←HBLKSIZE)
/* max size objects supported by freelist (larger objects may be */
/* allocated, but less efficiently) */
#define CPP←MAXOBJSZ BYTES←TO←WORDS(CPP←HBLKSIZE/2)
#define MAXOBJSZ ((word)CPP←MAXOBJSZ)
# define divHBLKSZ(n) ((n) >> LOG←HBLKSIZE)
# define HBLK←PTR←DIFF(p,q) divHBLKSZ((ptr←t)p - (ptr←t)q)
/* Equivalent to subtracting 2 hblk pointers. */
/* We do it this way because a compiler should */
/* find it hard to use an integer division */
/* instead of a shift. The bundled SunOS 4.1 */
/* o.w. sometimes pessimizes the subtraction to */
/* involve a call to .div. */
# define modHBLKSZ(n) ((n) & (HBLKSIZE-1))
# define HBLKPTR(objptr) ((struct hblk *)(((word) (objptr)) & ~(HBLKSIZE-1)))
# define HBLKDISPL(objptr) (((word) (objptr)) & (HBLKSIZE-1))
/* Round up byte allocation requests to integral number of words: */
# ifdef ALL←INTERIOR←POINTERS
# define ROUNDED←UP←WORDS(n) BYTES←TO←WORDS((n) + WORDS←TO←BYTES(1))
# else
# define ROUNDED←UP←WORDS(n) BYTES←TO←WORDS((n) + WORDS←TO←BYTES(1) - 1)
# endif
/*
* Hash table representation of sets of pages. This assumes it is
* OK to add spurious entries to sets.
* Used by black-listing code, and perhaps by dirty bit maintenance code.
*/
# define LOG←PHT←ENTRIES 14 /* Collisions are likely if heap grows */
/* to more than 16K hblks = 64MB. */
/* Each hash table occupies 2K bytes. */
# define PHT←ENTRIES ((word)1 << LOG←PHT←ENTRIES)
# define PHT←SIZE (PHT←ENTRIES >> LOGWL)
typedef word page←hash←table[PHT←SIZE];
# define PHT←HASH(addr) ((((word)(addr)) >> LOG←HBLKSIZE) & (PHT←ENTRIES - 1))
# define get←pht←entry←from←index(bl, index) \
(((bl)[divWORDSZ(index)] >> modWORDSZ(index)) & 1)
# define set←pht←entry←from←index(bl, index) \
(bl)[divWORDSZ(index)] |= (word)1 << modWORDSZ(index)
# define clear←pht←entry←from←index(bl, index) \
(bl)[divWORDSZ(index)] &= ~((word)1 << modWORDSZ(index))
/********************************************/
/* */
/* H e a p B l o c k s */
/* */
/********************************************/
/* heap block header */
#define HBLKMASK (HBLKSIZE-1)
#define BITS←PER←HBLK (HBLKSIZE * 8)
#define MARK←BITS←PER←HBLK (BITS←PER←HBLK/CPP←WORDSZ)
/* upper bound */
/* We allocate 1 bit/word. Only the first word */
/* in each object is actually marked. */
# ifdef ALIGN←DOUBLE
# define MARK←BITS←SZ (((MARK←BITS←PER←HBLK + 2*CPP←WORDSZ - 1) \
/ (2*CPP←WORDSZ))*2)
# else
# define MARK←BITS←SZ ((MARK←BITS←PER←HBLK + CPP←WORDSZ - 1)/CPP←WORDSZ)
# endif
/* Upper bound on number of mark words per heap block */
/* Mark stack entries. */
typedef struct ms←entry {
word * mse←start; /* inclusive */
word * mse←end; /* exclusive */
} mse;
typedef mse * (*mark←proc)(/* word * addr, hdr * hhdr, mse * msp, mse * msl */);
/* Procedure to arrange for the descendents of the object at */
/* addr to be marked. Msp points at the top entry on the */
/* mark stack. Msl delimits the hot end of the mark stack. */
/* hhdr is the hdr structure corresponding to addr. */
/* Returns the new mark stack pointer. */
struct hblkhdr {
word hb←sz; /* If in use, size in words, of objects in the block. */
/* if free, the size in bytes of the whole block */
struct hblk * hb←next; /* Link field for hblk free list */
/* and for lists of chunks waiting to be */
/* reclaimed. */
mark←proc hb←mark←proc; /* Procedure to mark objects. Can */
/* also be retrived through obj←kind. */
/* But one level of indirection matters */
/* here. */
char* hb←map; /* A pointer to a pointer validity map of the block. */
/* See GC←obj←map. */
/* Valid for all blocks with headers. */
/* Free blocks point to GC←invalid←map. */
unsigned short hb←obj←kind;
/* Kind of objects in the block. Each kind */
/* identifies a mark procedure and a set of */
/* list headers. sometimes called regions. */
unsigned short hb←last←reclaimed;
/* Value of GC←gc←no when block was */
/* last allocated or swept. May wrap. */
word hb←marks[MARK←BITS←SZ];
/* Bit i in the array refers to the */
/* object starting at the ith word (header */
/* INCLUDED) in the heap block. */
/* The lsb of word 0 is numbered 0. */
};
/* heap block body */
# define DISCARD←WORDS 0
/* Number of words to be dropped at the beginning of each block */
/* Must be a multiple of WORDSZ. May reasonably be nonzero */
/* on machines that don't guarantee longword alignment of */
/* pointers, so that the number of false hits is minimized. */
/* 0 and WORDSZ are probably the only reasonable values. */
# define BODY←SZ ((HBLKSIZE-WORDS←TO←BYTES(DISCARD←WORDS))/sizeof(word))
struct hblk {
# if (DISCARD←WORDS != 0)
word garbage[DISCARD←WORDS];
# endif
word hb←body[BODY←SZ];
};
# define HDR←WORDS ((word)DISCARD←WORDS)
# define HDR←BYTES ((word)WORDS←TO←BYTES(DISCARD←WORDS))
# define OBJ←SZ←TO←BLOCKS(sz) \
divHBLKSZ(HDR←BYTES + WORDS←TO←BYTES(sz) + HBLKSIZE-1)
/* Size of block (in units of HBLKSIZE) needed to hold objects of */
/* given sz (in words). */
/* Object free list link */
# define obj←link(p) (*(ptr←t *)(p))
/* lists of all heap blocks and free lists */
/* These are grouped together in a struct */
/* so that they can be easily skipped by the */
/* GC←mark routine. */
/* The ordering is weird to make GC←malloc */
/* faster by keeping the important fields */
/* sufficiently close together that a */
/* single load of a base register will do. */
/* Scalars that could easily appear to */
/* be pointers are also put here. */
struct ←GC←arrays {
word ←heapsize;
ptr←t ←last←heap←addr;
ptr←t ←prev←heap←addr;
word ←words←allocd←before←gc;
/* Number of words allocated before this */
/* collection cycle. */
# ifdef GATHERSTATS
word ←composite←in←use;
/* Number of words in accessible composite */
/* objects. */
word ←atomic←in←use;
/* Number of words in accessible atomic */
/* objects. */
# endif
word ←words←allocd;
/* Number of words allocated during this collection cycle */
word ←words←wasted;
/* Number of words wasted due to internal fragmentation */
/* in large objects allocated since last gc. Approximate.*/
word ←non←gc←bytes←at←gc;
/* Number of explicitly managed bytes of storage */
/* at last collection. */
word ←mem←freed;
/* Number of explicitly deallocated words of memory */
/* since last collection. */
ptr←t ←objfreelist[MAXOBJSZ+1];
/* free list for objects */
# ifdef MERGE←SIZES
unsigned ←size←map[WORDS←TO←BYTES(MAXOBJSZ+1)];
/* Number of words to allocate for a given allocation request in */
/* bytes. */
# endif
ptr←t ←aobjfreelist[MAXOBJSZ+1];
/* free list for atomic objs */
ptr←t ←uobjfreelist[MAXOBJSZ+1];
/* uncollectable but traced objs */
# ifdef STUBBORN←ALLOC
ptr←t ←sobjfreelist[MAXOBJSZ+1];
# endif
/* free list for immutable objects */
ptr←t ←obj←map[MAXOBJSZ+1];
/* If not NIL, then a pointer to a map of valid */
/* object addresses. hbh←map[sz][i] is j if the */
/* address block←start+i is a valid pointer */
/* to an object at */
/* block←start+i&~3 - WORDS←TO←BYTES(j). */
/* (If ALL←INTERIOR←POINTERS is defined, then */
/* instead ((short *)(hbh←map[sz])[i] is j if */
/* block←start+WORDS←TO←BYTES(i) is in the */
/* interior of an object starting at */
/* block←start+WORDS←TO←BYTES(i-j)). */
/* It is OBJ←INVALID if */
/* block←start+WORDS←TO←BYTES(i) is not */
/* valid as a pointer to an object. */
/* We assume that all values of j <= OBJ←INVALID */
/* The zeroth entry corresponds to large objects.*/
# ifdef ALL←INTERIOR←POINTERS
# define map←entry←type short
# define OBJ←INVALID 0x7fff
# define MAP←ENTRY(map, bytes) \
(((map←entry←type *)(map))[BYTES←TO←WORDS(bytes)])
# define MAP←ENTRIES BYTES←TO←WORDS(HBLKSIZE)
# define MAP←SIZE (MAP←ENTRIES * sizeof(map←entry←type))
# define OFFSET←VALID(displ) TRUE
# define CPP←MAX←OFFSET (HBLKSIZE - HDR←BYTES - 1)
# define MAX←OFFSET ((word)CPP←MAX←OFFSET)
# else
# define map←entry←type char
# define OBJ←INVALID 0x7f
# define MAP←ENTRY(map, bytes) \
(map)[bytes]
# define MAP←ENTRIES HBLKSIZE
# define MAP←SIZE MAP←ENTRIES
# define CPP←MAX←OFFSET (WORDS←TO←BYTES(OBJ←INVALID) - 1)
# define MAX←OFFSET ((word)CPP←MAX←OFFSET)
# define VALID←OFFSET←SZ \
(CPP←MAX←OFFSET > WORDS←TO←BYTES(CPP←MAXOBJSZ)? \
CPP←MAX←OFFSET+1 \
: WORDS←TO←BYTES(CPP←MAXOBJSZ)+1)
char ←valid←offsets[VALID←OFFSET←SZ];
/* GC←valid←offsets[i] == TRUE ==> i */
/* is registered as a displacement. */
# define OFFSET←VALID(displ) GC←valid←offsets[displ]
char ←modws←valid←offsets[sizeof(word)];
/* GC←valid←offsets[i] ==> */
/* GC←modws←valid←offsets[i%sizeof(word)] */
# endif
struct hblk * ←reclaim←list[MAXOBJSZ+1];
struct hblk * ←areclaim←list[MAXOBJSZ+1];
struct hblk * ←ureclaim←list[MAXOBJSZ+1];
# ifdef STUBBORN←ALLOC
struct hblk * ←sreclaim←list[MAXOBJSZ+1];
page←hash←table ←changed←pages;
/* Stubborn object pages that were changes since last call to */
/* GC←read←changed. */
page←hash←table ←prev←changed←pages;
/* Stubborn object pages that were changes before last call to */
/* GC←read←changed. */
# endif
# if defined(PROC←VDB) || defined(MPROTECT←VDB)
page←hash←table ←grungy←pages; /* Pages that were dirty at last */
/* GC←read←dirty. */
# endif
# define MAX←HEAP←SECTS 256 /* Separately added heap sections. */
struct HeapSect {
ptr←t hs←start; word hs←bytes;
} ←heap←sects[MAX←HEAP←SECTS];
/* Block header index; see gc←headers.h */
bottom←index ←all←nils;
bottom←index * ←top←index [TOP←SZ];
};
extern struct ←GC←arrays GC←arrays;
# define GC←objfreelist GC←arrays.←objfreelist
# define GC←aobjfreelist GC←arrays.←aobjfreelist
# define GC←uobjfreelist GC←arrays.←uobjfreelist
# define GC←sobjfreelist GC←arrays.←sobjfreelist
# define GC←valid←offsets GC←arrays.←valid←offsets
# define GC←modws←valid←offsets GC←arrays.←modws←valid←offsets
# define GC←reclaim←list GC←arrays.←reclaim←list
# define GC←areclaim←list GC←arrays.←areclaim←list
# define GC←ureclaim←list GC←arrays.←ureclaim←list
# ifdef STUBBORN←ALLOC
# define GC←sreclaim←list GC←arrays.←sreclaim←list
# define GC←changed←pages GC←arrays.←changed←pages
# define GC←prev←changed←pages GC←arrays.←prev←changed←pages
# endif
# define GC←obj←map GC←arrays.←obj←map
# define GC←last←heap←addr GC←arrays.←last←heap←addr
# define GC←prev←heap←addr GC←arrays.←prev←heap←addr
# define GC←words←allocd GC←arrays.←words←allocd
# define GC←words←wasted GC←arrays.←words←wasted
# define GC←non←gc←bytes←at←gc GC←arrays.←non←gc←bytes←at←gc
# define GC←mem←freed GC←arrays.←mem←freed
# define GC←heapsize GC←arrays.←heapsize
# define GC←words←allocd←before←gc GC←arrays.←words←allocd←before←gc
# define GC←heap←sects GC←arrays.←heap←sects
# define GC←all←nils GC←arrays.←all←nils
# define GC←top←index GC←arrays.←top←index
# if defined(PROC←VDB) || defined(MPROTECT←VDB)
# define GC←grungy←pages GC←arrays.←grungy←pages
# endif
# ifdef GATHERSTATS
# define GC←composite←in←use GC←arrays.←composite←in←use
# define GC←atomic←in←use GC←arrays.←atomic←in←use
# endif
# ifdef MERGE←SIZES
# define GC←size←map GC←arrays.←size←map
# endif
# define beginGC←arrays ((ptr←t)(&GC←arrays))
# define endGC←arrays (((ptr←t)(&GC←arrays)) + (sizeof GC←arrays))
# define MAXOBJKINDS 16
/* Object kinds: */
extern struct obj←kind {
ptr←t *ok←freelist; /* Array of free listheaders for this kind of object */
/* Point either to GC←arrays or to storage allocated */
/* with GC←scratch←alloc. */
struct hblk **ok←reclaim←list;
/* List headers for lists of blocks waiting to be */
/* swept. */
mark←proc ok←mark←proc; /* Procedure to either mark referenced objects, */
/* or push them on the mark stack. */
bool ok←init; /* Clear objects before putting them on the free list. */
} GC←obj←kinds[MAXOBJKINDS];
/* Predefined kinds: */
# define PTRFREE 0
# define NORMAL 1
# define UNCOLLECTABLE 2
# define STUBBORN 3
extern word GC←n←heap←sects; /* Number of separately added heap */
/* sections. */
extern int GC←n←kinds;
extern char * GC←invalid←map;
/* Pointer to the nowhere valid hblk map */
/* Blocks pointing to this map are free. */
extern struct hblk * GC←hblkfreelist;
/* List of completely empty heap blocks */
/* Linked through hb←next field of */
/* header structure associated with */
/* block. */
extern bool GC←is←initialized; /* GC←init() has been run. */
extern bool GC←objects←are←marked; /* There are marked objects in */
/* the heap. */
# ifndef PCR
extern ptr←t GC←stackbottom; /* Cool end of user stack */
# endif
extern word GC←hincr; /* current heap increment, in blocks */
extern word GC←root←size; /* Total size of registered root sections */
extern bool GC←debugging←started; /* GC←debug←malloc has been called. */
extern ptr←t GC←least←plausible←heap←addr;
extern ptr←t GC←greatest←plausible←heap←addr;
/* Bounds on the heap. Guaranteed valid */
/* Likely to include future heap expansion. */
/* Operations */
# define update←GC←hincr GC←hincr = (GC←hincr * HINCR←MULT)/HINCR←DIV; \
if (GC←hincr > MAXHINCR) {GC←hincr = MAXHINCR;}
# ifndef abs
# define abs(x) ((x) < 0? (-(x)) : (x))
# endif
/* Marks are in a reserved area in */
/* each heap block. Each word has one mark bit associated */
/* with it. Only those corresponding to the beginning of an */
/* object are used. */
/* Mark bit perations */
/*
* Retrieve, set, clear the mark bit corresponding
* to the nth word in a given heap block.
*
* (Recall that bit n corresponds to object beginning at word n
* relative to the beginning of the block, including unused words)
*/
# define mark←bit←from←hdr(hhdr,n) (((hhdr)->hb←marks[divWORDSZ(n)] \
>> (modWORDSZ(n))) & (word)1)
# define set←mark←bit←from←hdr(hhdr,n) (hhdr)->hb←marks[divWORDSZ(n)] \
|= (word)1 << modWORDSZ(n)
# define clear←mark←bit←from←hdr(hhdr,n) (hhdr)->hb←marks[divWORDSZ(n)] \
&= ~((word)1 << modWORDSZ(n))
/* Important internal collector routines */
void GC←apply←to←all←blocks(/*fn, client←data*/);
/* Invoke fn(hbp, client←data) for each */
/* allocated heap block. */
struct hblk * GC←next←block(/* struct hblk * h */);
mse * GC←no←mark←proc(/*addr,hhdr,msp,msl*/);
/* Mark procedure for PTRFREE objects. */
mse * GC←normal←mark←proc(/*addr,hhdr,msp,msl*/);
/* Mark procedure for NORMAL objects. */
void GC←mark←init();
void GC←clear←marks(); /* Clear mark bits for all heap objects. */
void GC←mark←from←mark←stack(); /* Mark from everything on the mark stack. */
/* Return after about one pages worth of */
/* work. */
bool GC←mark←stack←empty();
bool GC←mark←some(); /* Perform about one pages worth of marking */
/* work of whatever kind is needed. Returns */
/* quickly if no collection is in progress. */
/* Return TRUE if mark phase finished. */
void GC←initiate←full(); /* initiate full collection. */
void GC←initiate←partial(); /* initiate partial collection. */
void GC←push←all(/*b,t*/); /* Push everything in a range */
/* onto mark stack. */
void GC←push←dirty(/*b,t*/); /* Push all possibly changed */
/* subintervals of [b,t) onto */
/* mark stack. */
void GC←push←conditional(/* ptr←t b, ptr←t t, bool all*/);
/* Do either of the above, depending */
/* on the third arg. */
void GC←push←all←stack(/*b,t*/); /* As above, but consider */
/* interior pointers as valid */
void GC←remark(); /* Mark from all marked objects. Used */
/* only if we had to drop something. */
void GC←push←one(/*p*/); /* If p points to an object, mark it */
/* and push contents on the mark stack */
void GC←push←one←checked(/*p*/); /* Ditto, omits plausibility test */
void GC←push←marked(/* struct hblk h, hdr * hhdr */);
/* Push contents of all marked objects in h onto */
/* mark stack. */
struct hblk * GC←push←next←marked←dirty(/* h */);
/* Invoke GC←push←marked on next dirty block above h. */
/* Return a pointer just past the end of this block. */
struct hblk * GC←push←next←marked(/* h */);
/* Ditto, but also mark from clean pages. */
struct hblk * GC←push←next←marked←uncollectable(/* h */);
/* Ditto, but mark only from uncollectable pages. */
void GC←stopped←mark(); /* Mark from all roots and rescuers */
/* with the world stopped. */
void GC←clear←hdr←marks(/* hhdr */); /* Clear the mark bits in a header */
void GC←add←roots←inner();
void GC←register←dynamic←libraries();
/* Add dynamic library data sections to the root set. */
/* Machine dependent startup routines */
ptr←t GC←get←stack←base();
void GC←register←data←segments();
# ifndef ALL←INTERIOR←POINTERS
void GC←add←to←black←list←normal(/* bits */);
/* Register bits as a possible future false */
/* reference from the heap or static data */
# define GC←ADD←TO←BLACK←LIST←NORMAL(bits) GC←add←to←black←list←normal(bits)
# else
# define GC←ADD←TO←BLACK←LIST←NORMAL(bits) GC←add←to←black←list←stack(bits)
# endif
void GC←add←to←black←list←stack(/* bits */);
struct hblk * GC←is←black←listed(/* h, len */);
/* If there are likely to be false references */
/* to a block starting at h of the indicated */
/* length, then return the next plausible */
/* starting location for h that might avoid */
/* these false references. */
void GC←promote←black←lists();
/* Declare an end to a black listing phase. */
ptr←t GC←scratch←alloc(/*bytes*/);
/* GC internal memory allocation for */
/* small objects. Deallocation is not */
/* possible. */
void GC←invalidate←map(/* hdr */);
/* Remove the object map associated */
/* with the block. This identifies */
/* the block as invalid to the mark */
/* routines. */
bool GC←add←map←entry(/*sz*/);
/* Add a heap block map for objects of */
/* size sz to obj←map. */
/* Return FALSE on failure. */
void GC←register←displacement←inner(/*offset*/);
/* Version of GC←register←displacement */
/* that assumes lock is already held */
/* and signals are already disabled. */
void GC←init←inner();
void GC←new←hblk(/*size←in←words, kind*/);
/* Allocate a new heap block, and build */
/* a free list in it. */
struct hblk * GC←allochblk(/*size←in←words, kind*/);
/* Allocate a heap block, clear it if */
/* for composite objects, inform */
/* the marker that block is valid */
/* for objects of indicated size. */
/* sz < 0 ==> atomic. */
void GC←freehblk(); /* Deallocate a heap block and mark it */
/* as invalid. */
void GC←start←reclaim(/*abort←if←found*/);
/* Restore unmarked objects to free */
/* lists, or (if abort←if←found is */
/* TRUE) report them. */
/* Sweeping of small object pages is */
/* largely deferred. */
void GC←continue←reclaim(/*size, kind*/);
/* Sweep pages of the given size and */
/* kind, as long as possible, and */
/* as long as the corr. free list is */
/* empty. */
void GC←reclaim←or←delete←all();
/* Arrange for all reclaim lists to be */
/* empty. Judiciously choose between */
/* sweeping and discarding each page. */
bool GC←gcollect←inner();
/* Collect; caller must have acquired */
/* lock and disabled signals. */
/* FALSE return indicates nothing was */
/* done due to insufficient allocation. */
void GC←finish←collection(); /* Finish collection. Mark bits are */
/* consistent and lock is still held. */
bool GC←collect←or←expand(/* needed←blocks */);
/* Collect or expand heap in an attempt */
/* make the indicated number of free */
/* blocks available. Should be called */
/* until it fails by returning FALSE. */
void GC←init(); /* Initialize collector. */
void GC←collect←a←little(/* n */);
/* Do n units worth of garbage */
/* collection work, if appropriate. */
/* A unit is an amount appropriate for */
/* HBLKSIZE bytes of allocation. */
ptr←t GC←generic←malloc(/* bytes, kind */);
/* Allocate an object of the given */
/* kind. By default, there are only */
/* two kinds: composite, and atomic. */
/* We claim it's possible for clever */
/* client code that understands GC */
/* internals to add more, e.g. to */
/* communicate object layout info */
/* to the collector. */
ptr←t GC←generic←malloc←inner(/* bytes, kind */);
/* Ditto, but I already hold lock, etc. */
ptr←t GC←generic←malloc←words←small(/*words, kind*/);
/* As above, but size in units of words */
/* Bypasses MERGE←SIZES. Assumes */
/* words <= MAXOBJSZ. */
ptr←t GC←allocobj(/* sz←inn←words, kind */);
/* Make the indicated */
/* free list nonempty, and return its */
/* head. */
bool GC←install←header(/*h*/);
/* Install a header for block h. */
/* Return FALSE on failure. */
bool GC←install←counts(/*h, sz*/);
/* Set up forwarding counts for block */
/* h of size sz. */
/* Return FALSE on failure. */
void GC←remove←header(/*h*/);
/* Remove the header for block h. */
void GC←remove←counts(/*h, sz*/);
/* Remove forwarding counts for h. */
hdr * GC←find←header(/*p*/); /* Debugging only. */
void GC←finalize(); /* Perform all indicated finalization actions */
/* on unmarked objects. */
void GC←add←to←heap(/*p, bytes*/);
/* Add a HBLKSIZE aligned chunk to the heap. */
void GC←print←obj(/* ptr←t p */);
/* P points to somewhere inside an object with */
/* debugging info. Print a human readable */
/* description of the object to stderr. */
extern void (*GC←check←heap)();
/* Check that all objects in the heap with */
/* debugging info are intact. Print */
/* descriptions of any that are not. */
/* Virtual dirty bit implementation: */
/* Each implementation exports the following: */
void GC←read←dirty(); /* Retrueve dirty bits. */
bool GC←page←was←dirty(/* struct hblk * h */);
/* Read retrieved dirty bits. */
void GC←write←hint(/* struct hblk * h */);
/* h is about to be written. */
void GC←dirty←init();
/* Slow/general mark bit manipulation: */
bool GC←is←marked();
void GC←clear←mark←bit();
void GC←set←mark←bit();
/* Stubborn objects: */
void GC←read←changed(); /* Analogous to GC←read←dirty */
bool GC←page←was←changed(/* h */); /* Analogous to GC←page←was←dirty */
void GC←clean←changing←list(); /* Collect obsolete changing list entries */
void GC←stubborn←init();
/* Debugging print routines: */
void GC←print←block←list();
void GC←print←hblkfreelist();
/* Logging and diagnostic output: */
void GC←printf(/* format, a, b, c, d, e, f */);
/* A version of printf that doesn't allocate, */
/* is restricted to long arguments, and */
/* (unfortunately) doesn't use varargs for */
/* portability. Restricted to 6 args and */
/* 1K total output length. */
/* (We use sprintf. Hopefully that doesn't */
/* allocate for long arguments.) */
# define GC←printf0(f) GC←printf(f, 0l, 0l, 0l, 0l, 0l, 0l)
# define GC←printf1(f,a) GC←printf(f, (long)a, 0l, 0l, 0l, 0l, 0l)
# define GC←printf2(f,a,b) GC←printf(f, (long)a, (long)b, 0l, 0l, 0l, 0l)
# define GC←printf3(f,a,b,c) GC←printf(f, (long)a, (long)b, (long)c, 0l, 0l, 0l)
# define GC←printf4(f,a,b,c,d) GC←printf(f, (long)a, (long)b, (long)c, \
(long)d, 0l, 0l)
# define GC←printf5(f,a,b,c,d,e) GC←printf(f, (long)a, (long)b, (long)c, \
(long)d, (long)e, 0l)
# define GC←printf6(f,a,b,c,d,e,g) GC←printf(f, (long)a, (long)b, (long)c, \
(long)d, (long)e, (long)g)
void GC←err←printf(/* format, a, b, c, d, e, f */);
# define GC←err←printf0(f) GC←err←puts(f)
# define GC←err←printf1(f,a) GC←err←printf(f, (long)a, 0l, 0l, 0l, 0l, 0l)
# define GC←err←printf2(f,a,b) GC←err←printf(f, (long)a, (long)b, 0l, 0l, 0l, 0l)
# define GC←err←printf3(f,a,b,c) GC←err←printf(f, (long)a, (long)b, (long)c, \
0l, 0l, 0l)
# define GC←err←printf4(f,a,b,c,d) GC←err←printf(f, (long)a, (long)b, \
(long)c, (long)d, 0l, 0l)
# define GC←err←printf5(f,a,b,c,d,e) GC←err←printf(f, (long)a, (long)b, \
(long)c, (long)d, \
(long)e, 0l)
# define GC←err←printf6(f,a,b,c,d,e,g) GC←err←printf(f, (long)a, (long)b, \
(long)c, (long)d, \
(long)e, (long)g)
/* Ditto, writes to stderr. */
void GC←err←puts(/* char *s */);
/* Write s to stderr, don't buffer, don't add */
/* newlines, don't ... */
# endif /* GC←PRIVATE←H */