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Diffstat (limited to 'tools/build/src/engine/boehm_gc/include/gc_tiny_fl.h')
| -rw-r--r-- | tools/build/src/engine/boehm_gc/include/gc_tiny_fl.h | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/tools/build/src/engine/boehm_gc/include/gc_tiny_fl.h b/tools/build/src/engine/boehm_gc/include/gc_tiny_fl.h new file mode 100644 index 000000000..52b6864b6 --- /dev/null +++ b/tools/build/src/engine/boehm_gc/include/gc_tiny_fl.h @@ -0,0 +1,89 @@ +/* + * Copyright (c) 1999-2005 Hewlett-Packard Development Company, L.P. + * + * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED + * OR IMPLIED. ANY USE IS AT YOUR OWN RISK. + * + * Permission is hereby granted to use or copy this program + * for any purpose, provided the above notices are retained on all copies. + * Permission to modify the code and to distribute modified code is granted, + * provided the above notices are retained, and a notice that the code was + * modified is included with the above copyright notice. + */ + +#ifndef GC_TINY_FL_H +#define GC_TINY_FL_H +/* + * Constants and data structures for "tiny" free lists. + * These are used for thread-local allocation or in-lined allocators. + * Each global free list also essentially starts with one of these. + * However, global free lists are known to the GC. "Tiny" free lists + * are basically private to the client. Their contents are viewed as + * "in use" and marked accordingly by the core of the GC. + * + * Note that inlined code might know about the layout of these and the constants + * involved. Thus any change here may invalidate clients, and such changes should + * be avoided. Hence we keep this as simple as possible. + */ + +/* + * We always set GRANULE_BYTES to twice the length of a pointer. + * This means that all allocation requests are rounded up to the next + * multiple of 16 on 64-bit architectures or 8 on 32-bit architectures. + * This appears to be a reasonable compromise between fragmentation overhead + * and space usage for mark bits (usually mark bytes). + * On many 64-bit architectures some memory references require 16-byte + * alignment, making this necessary anyway. + * For a few 32-bit architecture (e.g. x86), we may also need 16-byte alignment + * for certain memory references. But currently that does not seem to be the + * default for all conventional malloc implementations, so we ignore that + * problem. + * It would always be safe, and often useful, to be able to allocate very + * small objects with smaller alignment. But that would cost us mark bit + * space, so we no longer do so. + */ +#ifndef GC_GRANULE_BYTES + /* GC_GRANULE_BYTES should not be overridden in any instances of the GC */ + /* library that may be shared between applications, since it affects */ + /* the binary interface to the library. */ +# if defined(__LP64__) || defined (_LP64) || defined(_WIN64) \ + || defined(__s390x__) || defined(__x86_64__) \ + || defined(__alpha__) || defined(__powerpc64__) \ + || defined(__arch64__) +# define GC_GRANULE_BYTES 16 +# define GC_GRANULE_WORDS 2 +# else +# define GC_GRANULE_BYTES 8 +# define GC_GRANULE_WORDS 2 +# endif +#endif /* !GC_GRANULE_BYTES */ + +#if GC_GRANULE_WORDS == 2 +# define GC_WORDS_TO_GRANULES(n) ((n)>>1) +#else +# define GC_WORDS_TO_GRANULES(n) ((n)*sizeof(void *)/GRANULE_BYTES) +#endif + +/* A "tiny" free list header contains TINY_FREELISTS pointers to */ +/* singly linked lists of objects of different sizes, the ith one */ +/* containing objects i granules in size. Note that there is a list */ +/* of size zero objects. */ +#ifndef GC_TINY_FREELISTS +# if GC_GRANULE_BYTES == 16 +# define GC_TINY_FREELISTS 25 +# else +# define GC_TINY_FREELISTS 33 /* Up to and including 256 bytes */ +# endif +#endif /* !GC_TINY_FREELISTS */ + +/* The ith free list corresponds to size i*GRANULE_BYTES */ +/* Internally to the collector, the index can be computed with */ +/* ROUNDED_UP_GRANULES. Externally, we don't know whether */ +/* DONT_ADD_BYTE_AT_END is set, but the client should know. */ + +/* Convert a free list index to the actual size of objects */ +/* on that list, including extra space we added. Not an */ +/* inverse of the above. */ +#define RAW_BYTES_FROM_INDEX(i) ((i) * GC_GRANULE_BYTES) + +#endif /* GC_TINY_FL_H */ |