+2014-04-15 Paul Eggert <eggert@cs.ucla.edu>
+
+ Remove DATA_SEG_BITS.
+ The DATA_SEG_BITS hack was needed for older 32 bit platforms.
+ As a result of this change, Emacs won't work on IRIX 6.5 with IRIX
+ cc, but that platform is so old that SGI itself stopped supporting
+ it in December 2013. If you still need Emacs on IRIX, please
+ either compile with GCC and port the undumping code, or run
+ './configure --with-wide-int'.
+ * alloc.c (gdb_make_enums_visible): Update to match lisp.h.
+ * lisp.h (GCTYPEBITS): Move definition up, and switch to the
+ DEFINE_GDB_SYMBOL_START way to define it.
+ (NONPOINTER_BITS): New macro.
+ (EMACS_INT): Use it.
+ [!USE_LSB_TAG && !WIDE_EMACS_INT]: Fail, and suggest reporting
+ the problem and/or configuring --with-wide-int.
+ (USE_LSB_TAG): Simplify, based on above changes.
+ (gdb_DATA_SEG_BITS): Remove. All uses removed.
+ * vm-limit.c (exceeds_lisp_ptr): Remove. All uses removed.
+
2014-04-12 Eli Zaretskii <eliz@gnu.org>
* xdisp.c (move_it_by_lines): If a large portion of buffer text is
/* Number of elements in an array. */
#define ARRAYELTS(arr) (sizeof (arr) / sizeof (arr)[0])
+/* Number of bits in a Lisp_Object tag. */
+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))
+# 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
#ifndef EMACS_INT_MAX
# if INTPTR_MAX <= 0
# error "INTPTR_MAX misconfigured"
-# elif INTPTR_MAX <= INT_MAX && !defined WIDE_EMACS_INT
+# elif INTPTR_MAX <= INT_MAX >> NONPOINTER_BITS && !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 && !defined WIDE_EMACS_INT
+# elif INTPTR_MAX <= LONG_MAX >> NONPOINTER_BITS && !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;
enum Lisp_Bits
{
- /* Number of bits in a Lisp_Object tag. This can be used in #if,
- and for GDB's sake also as a regular symbol. */
- GCTYPEBITS =
-#define GCTYPEBITS 3
- GCTYPEBITS,
-
/* 2**GCTYPEBITS. This must be a macro that expands to a literal
integer constant, for MSVC. */
#define GCALIGNMENT 8
This can be used in #if, e.g., '#if VAL_MAX < UINTPTR_MAX' below. */
#define VAL_MAX (EMACS_INT_MAX >> (GCTYPEBITS - 1))
-/* Unless otherwise specified, use USE_LSB_TAG on systems where: */
-#ifndef USE_LSB_TAG
-/* 1. We know malloc returns a multiple of 8. */
-# if (defined GNU_MALLOC || defined DOUG_LEA_MALLOC || defined __GLIBC__ \
- || defined DARWIN_OS || defined __sun)
-/* 2. We can specify multiple-of-8 alignment on static variables. */
-# ifdef alignas
-/* 3. Pointers-as-ints exceed VAL_MAX.
+/* Whether the least-significant bits of an EMACS_INT contain the tag.
On hosts where pointers-as-ints do not exceed VAL_MAX, USE_LSB_TAG is:
a. unnecessary, because the top bits of an EMACS_INT are unused, and
b. slower, because it typically requires extra masking.
- So, default USE_LSB_TAG to true only on hosts where it might be useful. */
-# if VAL_MAX < UINTPTR_MAX
-# define USE_LSB_TAG true
-# endif
-# endif
-# endif
-#endif
-#ifdef USE_LSB_TAG
-# undef USE_LSB_TAG
-enum enum_USE_LSB_TAG { USE_LSB_TAG = true };
-# define USE_LSB_TAG true
-#else
-enum enum_USE_LSB_TAG { USE_LSB_TAG = false };
-# define USE_LSB_TAG false
+ So, USE_LSB_TAG is true only on hosts where it might be useful. */
+DEFINE_GDB_SYMBOL_BEGIN (bool, USE_LSB_TAG)
+#define USE_LSB_TAG (EMACS_INT_MAX >> GCTYPEBITS < INTPTR_MAX)
+DEFINE_GDB_SYMBOL_END (USE_LSB_TAG)
+
+#if !USE_LSB_TAG && !defined WIDE_EMACS_INT
+# error "USE_LSB_TAG not supported on this platform; please report this." \
+ "Try 'configure --with-wide-int' to work around the problem."
+error !;
#endif
#ifndef alignas
#define lisp_h_XCONS(a) \
(eassert (CONSP (a)), (struct Lisp_Cons *) XUNTAG (a, Lisp_Cons))
#define lisp_h_XHASH(a) XUINT (a)
-#define lisp_h_XPNTR(a) \
- ((void *) (intptr_t) ((XLI (a) & VALMASK) | DATA_SEG_BITS))
+#define lisp_h_XPNTR(a) ((void *) (intptr_t) (XLI (a) & VALMASK))
#define lisp_h_XSYMBOL(a) \
(eassert (SYMBOLP (a)), (struct Lisp_Symbol *) XUNTAG (a, Lisp_Symbol))
#ifndef GC_CHECK_CONS_LIST
PVEC_FONT /* Should be last because it's used for range checking. */
};
-/* DATA_SEG_BITS forces extra bits to be or'd in with any pointers
- which were stored in a Lisp_Object. */
-#ifndef DATA_SEG_BITS
-# define DATA_SEG_BITS 0
-#endif
-enum { gdb_DATA_SEG_BITS = DATA_SEG_BITS };
-#undef DATA_SEG_BITS
-
enum More_Lisp_Bits
{
- DATA_SEG_BITS = gdb_DATA_SEG_BITS,
-
/* For convenience, we also store the number of elements in these bits.
Note that this size is not necessarily the memory-footprint size, but
only the number of Lisp_Object fields (that need to be traced by GC).
projects / emacs.git / commitdiff