Merge branch 'master' of git.savannah.gnu.org:/srv/git/emacs into feature/pgtk

1 files changed, 27 insertions, 19 deletions

diff --git a/src/alloc.c b/src/alloc.c
index ff3670eeb1d..2d25f8205ae 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;
@@ -1030,7 +1030,7 @@ lisp_malloc (size_t nbytes, bool clearit, enum mem_type type)
 #endif
 
   MALLOC_UNBLOCK_INPUT;
-  if (!val && nbytes)
+  if (!val)
     memory_full (nbytes);
   MALLOC_PROBE (nbytes);
   return val;
@@ -1329,16 +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
@@ -1352,8 +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
@@ -1361,7 +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;
@@ -1376,7 +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)
@@ -1929,8 +1938,7 @@ allocate_string_data (struct Lisp_String *s,
    The character is at byte offset CIDX_BYTE in the string.
    The character being replaced is CLEN bytes long,
    and the character that will replace it is NEW_CLEN bytes long.
-   Return the address of where the caller should store the
-   the new character.  */
+   Return the address where the caller should store the new character.  */
 
 unsigned char *
 resize_string_data (Lisp_Object string, ptrdiff_t cidx_byte,
@@ -7321,7 +7329,7 @@ Frames, windows, buffers, and subprocesses count as vectors
                 make_int (strings_consed));
 }
 
-#ifdef GNU_LINUX
+#if defined GNU_LINUX && defined __GLIBC__
 DEFUN ("malloc-info", Fmalloc_info, Smalloc_info, 0, 0, "",
        doc: /* Report malloc information to stderr.
 This function outputs to stderr an XML-formatted
@@ -7681,7 +7689,7 @@ N should be nonnegative.  */);
   defsubr (&Sgarbage_collect_maybe);
   defsubr (&Smemory_info);
   defsubr (&Smemory_use_counts);
-#ifdef GNU_LINUX
+#if defined GNU_LINUX && defined __GLIBC__
   defsubr (&Smalloc_info);
 #endif
   defsubr (&Ssuspicious_object);