Port to FreeBSD 11-CURRENT i386

Problem reported by Herbert J. Skuhra in:
http://lists.gnu.org/archive/html/emacs-devel/2016-02/msg00354.html
Instead of trying
* src/alloc.c (lmalloc, lrealloc, laligned): New functions.
(xmalloc, xzalloc, xrealloc, lisp_malloc): Use them.
(__alignof__) [!__GNUC__ && !__alignof__]: New macro.
(MALLOC_IS_GC_ALIGNED): New macro.
* src/lisp.h (NONPOINTER_BITS): Remove.  All uses removed.
No longer needed now that alloc.c uses lmalloc and lrealloc.

2 files changed, 66 insertions, 23 deletions

diff --git a/src/alloc.c b/src/alloc.c
index 6c6c1aade8e..8816411bcaf 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -802,8 +802,10 @@ malloc_unblock_input (void)
       malloc_probe (size);                      \
   } while (0)
 
+static void *lmalloc (size_t) ATTRIBUTE_MALLOC_SIZE ((1));
+static void *lrealloc (void *, size_t);
 
-/* Like malloc but check for no memory and block interrupt input..  */
+/* Like malloc but check for no memory and block interrupt input.  */
 
 void *
 xmalloc (size_t size)
@@ -811,7 +813,7 @@ xmalloc (size_t size)
   void *val;
 
   MALLOC_BLOCK_INPUT;
-  val = malloc (size);
+  val = lmalloc (size);
   MALLOC_UNBLOCK_INPUT;
 
   if (!val && size)
@@ -828,7 +830,7 @@ xzalloc (size_t size)
   void *val;
 
   MALLOC_BLOCK_INPUT;
-  val = malloc (size);
+  val = lmalloc (size);
   MALLOC_UNBLOCK_INPUT;
 
   if (!val && size)
@@ -849,9 +851,9 @@ xrealloc (void *block, size_t size)
   /* We must call malloc explicitly when BLOCK is 0, since some
      reallocs don't do this.  */
   if (! block)
-    val = malloc (size);
+    val = lmalloc (size);
   else
-    val = realloc (block, size);
+    val = lrealloc (block, size);
   MALLOC_UNBLOCK_INPUT;
 
   if (!val && size)
@@ -1053,7 +1055,7 @@ lisp_malloc (size_t nbytes, enum mem_type type)
   allocated_mem_type = type;
 #endif
 
-  val = malloc (nbytes);
+  val = lmalloc (nbytes);
 
 #if ! USE_LSB_TAG
   /* If the memory just allocated cannot be addressed thru a Lisp
@@ -1356,6 +1358,62 @@ lisp_align_free (void *block)
   MALLOC_UNBLOCK_INPUT;
 }
 
+#if !defined __GNUC__ && !defined __alignof__
+# define __alignof__(type) alignof (type)
+#endif
+
+/* True if malloc returns a multiple of GCALIGNMENT.  In practice this
+   holds if __alignof__ (max_align_t) is a multiple.  Use __alignof__
+   if available, as otherwise this check would fail with GCC x86.
+   This is a macro, not an enum constant, for portability to HP-UX
+   10.20 cc and AIX 3.2.5 xlc.  */
+#define MALLOC_IS_GC_ALIGNED (__alignof__ (max_align_t) % GCALIGNMENT == 0)
+
+/* True if P is suitably aligned for SIZE, where Lisp alignment may be
+   needed if SIZE is Lisp-aligned.  */
+
+static bool
+laligned (void *p, size_t size)
+{
+  return (MALLOC_IS_GC_ALIGNED || size % GCALIGNMENT != 0
+          || (intptr_t) p % GCALIGNMENT == 0);
+}
+
+/* Like malloc and realloc except that if SIZE is Lisp-aligned, make
+   sure the result is too.  */
+
+static void *
+lmalloc (size_t size)
+{
+#if USE_ALIGNED_ALLOC
+  if (! MALLOC_IS_GC_ALIGNED)
+    return aligned_alloc (GCALIGNMENT, size);
+#endif
+
+  void *p;
+  while (true)
+    {
+      p = malloc (size);
+      if (laligned (p, size))
+        break;
+      free (p);
+    }
+
+  eassert ((intptr_t) p % GCALIGNMENT == 0);
+  return p;
+}
+
+static void *
+lrealloc (void *p, size_t size)
+{
+  do
+    p = realloc (p, size);
+  while (! laligned (p, size));
+
+  eassert ((intptr_t) p % GCALIGNMENT == 0);
+  return p;
+}
+
 
 /***********************************************************************
                          Interval Allocation
diff --git a/src/lisp.h b/src/lisp.h
index 82cbca8e6ba..e8eab7be9eb 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -67,19 +67,6 @@ DEFINE_GDB_SYMBOL_BEGIN (int, GCTYPEBITS)
 #define GCTYPEBITS 3
 DEFINE_GDB_SYMBOL_END (GCTYPEBITS)
 
-/* The number of bits needed in an EMACS_INT over and above the number
-   of bits in a pointer.  This is 0 on systems where:
-   1.  We can specify multiple-of-8 alignment on static variables.
-   2.  We know malloc returns a multiple of 8.  */
-#if (defined alignas \
-     && (defined GNU_MALLOC || defined DOUG_LEA_MALLOC || defined __GLIBC__ \
-         || defined DARWIN_OS || defined __sun || defined __MINGW32__ \
-         || defined CYGWIN))
-# define NONPOINTER_BITS 0
-#else
-# define NONPOINTER_BITS GCTYPEBITS
-#endif
-
 /* EMACS_INT - signed integer wide enough to hold an Emacs value
    EMACS_INT_MAX - maximum value of EMACS_INT; can be used in #if
    pI - printf length modifier for EMACS_INT
@@ -87,18 +74,16 @@ DEFINE_GDB_SYMBOL_END (GCTYPEBITS)
 #ifndef EMACS_INT_MAX
 # if INTPTR_MAX <= 0
 #  error "INTPTR_MAX misconfigured"
-# elif INTPTR_MAX <= INT_MAX >> NONPOINTER_BITS && !defined WIDE_EMACS_INT
+# elif INTPTR_MAX <= INT_MAX && !defined WIDE_EMACS_INT
 typedef int EMACS_INT;
 typedef unsigned int EMACS_UINT;
 #  define EMACS_INT_MAX INT_MAX
 #  define pI ""
-# elif INTPTR_MAX <= LONG_MAX >> NONPOINTER_BITS && !defined WIDE_EMACS_INT
+# elif INTPTR_MAX <= LONG_MAX && !defined WIDE_EMACS_INT
 typedef long int EMACS_INT;
 typedef unsigned long EMACS_UINT;
 #  define EMACS_INT_MAX LONG_MAX
 #  define pI "l"
-/* Check versus LLONG_MAX, not LLONG_MAX >> NONPOINTER_BITS.
-   In theory this is not safe, but in practice it seems to be OK.  */
 # elif INTPTR_MAX <= LLONG_MAX
 typedef long long int EMACS_INT;
 typedef unsigned long long int EMACS_UINT;