diff options
Diffstat (limited to 'src/alloc.c')
| -rw-r--r-- | src/alloc.c | 40 |
1 files changed, 24 insertions, 16 deletions
diff --git a/src/alloc.c b/src/alloc.c index 0c04d5cde05..aa790d3afae 100644 --- a/src/alloc.c +++ b/src/alloc.c @@ -765,7 +765,7 @@ xmalloc (size_t size) val = lmalloc (size, false); MALLOC_UNBLOCK_INPUT; - if (!val && size) + if (!val) memory_full (size); MALLOC_PROBE (size); return val; @@ -782,7 +782,7 @@ xzalloc (size_t size) val = lmalloc (size, true); MALLOC_UNBLOCK_INPUT; - if (!val && size) + if (!val) memory_full (size); MALLOC_PROBE (size); return val; @@ -796,15 +796,15 @@ xrealloc (void *block, size_t size) void *val; MALLOC_BLOCK_INPUT; - /* We must call malloc explicitly when BLOCK is 0, since some - reallocs don't do this. */ + /* Call lmalloc when BLOCK is null, for the benefit of long-obsolete + platforms lacking support for realloc (NULL, size). */ if (! block) val = lmalloc (size, false); else val = lrealloc (block, size); MALLOC_UNBLOCK_INPUT; - if (!val && size) + if (!val) memory_full (size); MALLOC_PROBE (size); return val; @@ -988,8 +988,7 @@ record_xmalloc (size_t size) /* Like malloc but used for allocating Lisp data. NBYTES is the number of bytes to allocate, TYPE describes the intended use of the - allocated memory block (for strings, for conses, ...). - NBYTES must be positive. */ + allocated memory block (for strings, for conses, ...). */ #if ! USE_LSB_TAG void *lisp_malloc_loser EXTERNALLY_VISIBLE; @@ -1330,16 +1329,20 @@ laligned (void *p, size_t size) || size % LISP_ALIGNMENT != 0); } -/* Like malloc and realloc except that if SIZE is Lisp-aligned, make - sure the result is too, if necessary by reallocating (typically - with larger and larger sizes) until the allocator returns a - Lisp-aligned pointer. Code that needs to allocate C heap memory +/* Like malloc and realloc except return null only on failure, + the result is Lisp-aligned if SIZE is, and lrealloc's pointer + argument must be nonnull. Code allocating C heap memory for a Lisp object should use one of these functions to obtain a pointer P; that way, if T is an enum Lisp_Type value and L == make_lisp_ptr (P, T), then XPNTR (L) == P and XTYPE (L) == T. + If CLEARIT, arrange for the allocated memory to be cleared. + This might use calloc, as calloc can be faster than malloc+memset. + On typical modern platforms these functions' loops do not iterate. - On now-rare (and perhaps nonexistent) platforms, the loops in + On now-rare (and perhaps nonexistent) platforms, the code can loop, + reallocating (typically with larger and larger sizes) until the + allocator returns a Lisp-aligned pointer. This loop in theory could repeat forever. If an infinite loop is possible on a platform, a build would surely loop and the builder can then send us a bug report. Adding a counter to try to detect any such loop @@ -1353,8 +1356,13 @@ lmalloc (size_t size, bool clearit) if (! MALLOC_IS_LISP_ALIGNED && size % LISP_ALIGNMENT == 0) { void *p = aligned_alloc (LISP_ALIGNMENT, size); - if (clearit && p) - memclear (p, size); + if (p) + { + if (clearit) + memclear (p, size); + } + else if (! (MALLOC_0_IS_NONNULL || size)) + return aligned_alloc (LISP_ALIGNMENT, LISP_ALIGNMENT); return p; } #endif @@ -1362,7 +1370,7 @@ lmalloc (size_t size, bool clearit) while (true) { void *p = clearit ? calloc (1, size) : malloc (size); - if (laligned (p, size)) + if (laligned (p, size) && (MALLOC_0_IS_NONNULL || size || p)) return p; free (p); size_t bigger = size + LISP_ALIGNMENT; @@ -1377,7 +1385,7 @@ lrealloc (void *p, size_t size) while (true) { p = realloc (p, size); - if (laligned (p, size)) + if (laligned (p, size) && (size || p)) return p; size_t bigger = size + LISP_ALIGNMENT; if (size < bigger) |