Commit bfe3e0a2 authored by Paul Eggert's avatar Paul Eggert

USE_LISP_UNION_TYPE + USE_LSB_TAG cleanup (Bug#11604)

* alloc.c (make_number) [!defined make_number]:
Remove, as lisp.h always defines this now.
(mark_maybe_pointer): Simplify since USE_LSB_TAG is always defined now.
(roundup_size): Verify that it is a power of 2.
* data.c (Fmake_variable_buffer_local, Fmake_local_variable):
* ftfont.c (ftfont_driver): Use LISP_INITIALLY_ZERO.
* lisp.h (USE_LSB_TAG): Allow the builder to compile with
-DUSE_LSB_TAG=0, to override the automatically-selected default.
USE_LSB_TAG now is always defined to be either 0 or 1.
All uses changed.
(union Lisp_Object): Don't worry about WORDS_BIGENDIAN; the
code works fine either way, and efficiency is not a concern here,
as the union type is for debugging, not for production.
(LISP_MAKE_RVALUE, make_number) [USE_LISP_UNION_TYPE]:
Use an inline function on all platforms when using the union type,
since this is simpler and 'static inline' can be used portably
within Emacs now.
(LISP_INITIALLY_ZERO): New macro.
(XFASTINT, XSETFASTINT) [USE_LISP_UNION_TYPE]: Remove.
(XSET) [USE_LISP_UNION_TYPE]: Don't overparenthesize.
parent 1cce6920
2012-06-13 Paul Eggert <eggert@cs.ucla.edu>
USE_LISP_UNION_TYPE + USE_LSB_TAG cleanup (Bug#11604)
* alloc.c (make_number) [!defined make_number]:
Remove, as lisp.h always defines this now.
(mark_maybe_pointer): Simplify since USE_LSB_TAG is always defined now.
(roundup_size): Verify that it is a power of 2.
* data.c (Fmake_variable_buffer_local, Fmake_local_variable):
* ftfont.c (ftfont_driver): Use LISP_INITIALLY_ZERO.
* lisp.h (USE_LSB_TAG): Allow the builder to compile with
-DUSE_LSB_TAG=0, to override the automatically-selected default.
USE_LSB_TAG now is always defined to be either 0 or 1.
All uses changed.
(union Lisp_Object): Don't worry about WORDS_BIGENDIAN; the
code works fine either way, and efficiency is not a concern here,
as the union type is for debugging, not for production.
(LISP_MAKE_RVALUE, make_number) [USE_LISP_UNION_TYPE]:
Use an inline function on all platforms when using the union type,
since this is simpler and 'static inline' can be used portably
within Emacs now.
(LISP_INITIALLY_ZERO): New macro.
(XFASTINT, XSETFASTINT) [USE_LISP_UNION_TYPE]: Remove.
(XSET) [USE_LISP_UNION_TYPE]: Don't overparenthesize.
2012-06-12 Glenn Morris <rgm@gnu.org>
* s/gnu-kfreebsd.h, s/hpux11.h, s/openbsd.h, s/sol2-10.h: Remove files.
......
......@@ -533,7 +533,7 @@ buffer_memory_full (ptrdiff_t nbytes)
}, \
c)
#ifdef USE_LSB_TAG
#if USE_LSB_TAG
# define XMALLOC_HEADER_ALIGNMENT \
COMMON_MULTIPLE (1 << GCTYPEBITS, XMALLOC_BASE_ALIGNMENT)
#else
......@@ -893,8 +893,8 @@ safe_alloca_unwind (Lisp_Object arg)
number of bytes to allocate, TYPE describes the intended use of the
allocated memory block (for strings, for conses, ...). */
#ifndef USE_LSB_TAG
static void *lisp_malloc_loser;
#if ! USE_LSB_TAG
void *lisp_malloc_loser EXTERNALLY_VISIBLE;
#endif
static void *
......@@ -910,7 +910,7 @@ lisp_malloc (size_t nbytes, enum mem_type type)
val = (void *) malloc (nbytes);
#ifndef USE_LSB_TAG
#if ! USE_LSB_TAG
/* If the memory just allocated cannot be addressed thru a Lisp
object's pointer, and it needs to be,
that's equivalent to running out of memory. */
......@@ -1091,7 +1091,7 @@ lisp_align_malloc (size_t nbytes, enum mem_type type)
mallopt (M_MMAP_MAX, MMAP_MAX_AREAS);
#endif
#ifndef USE_LSB_TAG
#if ! USE_LSB_TAG
/* If the memory just allocated cannot be addressed thru a Lisp
object's pointer, and it needs to be, that's equivalent to
running out of memory. */
......@@ -1584,20 +1584,6 @@ mark_interval_tree (register INTERVAL tree)
if (! NULL_INTERVAL_P (i)) \
(i) = balance_intervals (i); \
} while (0)
/* Number support. If USE_LISP_UNION_TYPE is in effect, we
can't create number objects in macros. */
#ifndef make_number
Lisp_Object
make_number (EMACS_INT n)
{
Lisp_Object obj;
obj.s.val = n;
obj.s.type = Lisp_Int;
return obj;
}
#endif
/* Convert the pointer-sized word P to EMACS_INT while preserving its
type and ptr fields. */
......@@ -2943,18 +2929,13 @@ enum
header_size = offsetof (struct Lisp_Vector, contents),
word_size = sizeof (Lisp_Object),
roundup_size = COMMON_MULTIPLE (sizeof (Lisp_Object),
#ifdef USE_LSB_TAG
8 /* Helps to maintain alignment constraints imposed by
assumption that least 3 bits of pointers are always 0. */
#else
1 /* If alignment doesn't matter, should round up
to sizeof (Lisp_Object) at least. */
#endif
)
USE_LSB_TAG ? 1 << GCTYPEBITS : 1)
};
/* Round up X to nearest mult-of-ROUNDUP_SIZE,
assuming ROUNDUP_SIZE is a power of 2. */
/* ROUNDUP_SIZE must be a power of 2. */
verify ((roundup_size & (roundup_size - 1)) == 0);
/* Round up X to nearest mult-of-ROUNDUP_SIZE. */
#define vroundup(x) (((x) + (roundup_size - 1)) & ~(roundup_size - 1))
......@@ -3171,7 +3152,7 @@ sweep_vectors (void)
== VECTOR_FREE_LIST_FLAG)
vector->header.next.nbytes =
vector->header.size & (VECTOR_BLOCK_SIZE - 1);
next = ADVANCE (vector, vector->header.next.nbytes);
/* While NEXT is not marked, try to coalesce with VECTOR,
......@@ -3189,7 +3170,7 @@ sweep_vectors (void)
vector->header.next.nbytes += nbytes;
next = ADVANCE (next, nbytes);
}
eassert (vector->header.next.nbytes % roundup_size == 0);
if (vector == (struct Lisp_Vector *) block->data
......@@ -3468,7 +3449,7 @@ usage: (make-byte-code ARGLIST BYTE-CODE CONSTANTS DEPTH &optional DOCSTRING INT
union aligned_Lisp_Symbol
{
struct Lisp_Symbol s;
#ifdef USE_LSB_TAG
#if USE_LSB_TAG
unsigned char c[(sizeof (struct Lisp_Symbol) + (1 << GCTYPEBITS) - 1)
& -(1 << GCTYPEBITS)];
#endif
......@@ -3574,7 +3555,7 @@ Its value and function definition are void, and its property list is nil. */)
union aligned_Lisp_Misc
{
union Lisp_Misc m;
#ifdef USE_LSB_TAG
#if USE_LSB_TAG
unsigned char c[(sizeof (union Lisp_Misc) + (1 << GCTYPEBITS) - 1)
& -(1 << GCTYPEBITS)];
#endif
......@@ -4556,14 +4537,10 @@ mark_maybe_pointer (void *p)
{
struct mem_node *m;
/* Quickly rule out some values which can't point to Lisp data. */
if ((intptr_t) p %
#ifdef USE_LSB_TAG
8 /* USE_LSB_TAG needs Lisp data to be aligned on multiples of 8. */
#else
2 /* We assume that Lisp data is aligned on even addresses. */
#endif
)
/* Quickly rule out some values which can't point to Lisp data.
USE_LSB_TAG needs Lisp data to be aligned on multiples of 1 << GCTYPEBITS.
Otherwise, assume that Lisp data is aligned on even addresses. */
if ((intptr_t) p % (USE_LSB_TAG ? 1 << GCTYPEBITS : 2))
return;
m = mem_find (p);
......@@ -4639,8 +4616,8 @@ mark_maybe_pointer (void *p)
wider than a pointer might allocate a Lisp_Object in non-adjacent halves.
If USE_LSB_TAG, the bottom half is not a valid pointer, but it should
suffice to widen it to to a Lisp_Object and check it that way. */
#if defined USE_LSB_TAG || VAL_MAX < UINTPTR_MAX
# if !defined USE_LSB_TAG && VAL_MAX < UINTPTR_MAX >> GCTYPEBITS
#if USE_LSB_TAG || VAL_MAX < UINTPTR_MAX
# if !USE_LSB_TAG && VAL_MAX < UINTPTR_MAX >> GCTYPEBITS
/* If tag bits straddle pointer-word boundaries, neither mark_maybe_pointer
nor mark_maybe_object can follow the pointers. This should not occur on
any practical porting target. */
......@@ -5069,7 +5046,7 @@ static void *
pure_alloc (size_t size, int type)
{
void *result;
#ifdef USE_LSB_TAG
#if USE_LSB_TAG
size_t alignment = (1 << GCTYPEBITS);
#else
size_t alignment = sizeof (EMACS_INT);
......
......@@ -1500,7 +1500,7 @@ The function `default-value' gets the default value and `set-default' sets it.
{
struct Lisp_Symbol *sym;
struct Lisp_Buffer_Local_Value *blv = NULL;
union Lisp_Val_Fwd valcontents IF_LINT (= {0});
union Lisp_Val_Fwd valcontents IF_LINT (= {LISP_INITIALLY_ZERO});
int forwarded IF_LINT (= 0);
CHECK_SYMBOL (variable);
......@@ -1577,7 +1577,7 @@ Instead, use `add-hook' and specify t for the LOCAL argument. */)
{
register Lisp_Object tem;
int forwarded IF_LINT (= 0);
union Lisp_Val_Fwd valcontents IF_LINT (= {0});
union Lisp_Val_Fwd valcontents IF_LINT (= {LISP_INITIALLY_ZERO});
struct Lisp_Symbol *sym;
struct Lisp_Buffer_Local_Value *blv = NULL;
......
......@@ -104,7 +104,7 @@ static const char emacs_copyright[] = "Copyright (C) 2012 Free Software Foundati
/* Make these values available in GDB, which doesn't see macros. */
#ifdef USE_LSB_TAG
#if USE_LSB_TAG
int gdb_use_lsb EXTERNALLY_VISIBLE = 1;
#else
int gdb_use_lsb EXTERNALLY_VISIBLE = 0;
......@@ -116,7 +116,7 @@ int gdb_use_union EXTERNALLY_VISIBLE = 1;
#endif
int gdb_valbits EXTERNALLY_VISIBLE = VALBITS;
int gdb_gctypebits EXTERNALLY_VISIBLE = GCTYPEBITS;
#if defined (DATA_SEG_BITS) && ! defined (USE_LSB_TAG)
#if defined DATA_SEG_BITS && !USE_LSB_TAG
uintptr_t gdb_data_seg_bits EXTERNALLY_VISIBLE = DATA_SEG_BITS;
#else
uintptr_t gdb_data_seg_bits EXTERNALLY_VISIBLE = 0;
......
......@@ -525,7 +525,7 @@ static int ftfont_variation_glyphs (struct font *, int c,
struct font_driver ftfont_driver =
{
0, /* Qfreetype */
LISP_INITIALLY_ZERO, /* Qfreetype */
0, /* case insensitive */
ftfont_get_cache,
ftfont_list,
......
......@@ -161,10 +161,8 @@ extern int suppress_checking EXTERNALLY_VISIBLE;
always 0, and we can thus use them to hold tag bits, without
restricting our addressing space.
If USE_LSB_TAG is not set, then we use the top 3 bits for tagging, thus
restricting our possible address range. Currently USE_LSB_TAG is not
allowed together with a union. This is not due to any fundamental
technical (or political ;-) problem: nobody wrote the code to do it yet.
If ! USE_LSB_TAG, then use the top 3 bits for tagging, thus
restricting our possible address range.
USE_LSB_TAG not only requires the least 3 bits of pointers returned by
malloc to be 0 but also needs to be able to impose a mult-of-8 alignment
......@@ -201,25 +199,31 @@ extern int suppress_checking EXTERNALLY_VISIBLE;
# endif
#endif
/* Let's USE_LSB_TAG on systems where we know malloc returns mult-of-8. */
#if (defined GNU_MALLOC || defined DOUG_LEA_MALLOC || defined __GLIBC__ \
|| defined DARWIN_OS || defined __sun)
/* We also need to be able to specify mult-of-8 alignment on static vars. */
# if defined DECL_ALIGN
/* On hosts where pointers-as-ints do not exceed VAL_MAX,
USE_LSB_TAG is:
/* 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 DECL_ALIGN
/* 3. Pointers-as-ints exceed VAL_MAX.
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, define USE_LSB_TAG only on hosts where it might be useful. */
# if VAL_MAX < UINTPTR_MAX
# define USE_LSB_TAG
So, default USE_LSB_TAG to 1 only on hosts where it might be useful. */
# if VAL_MAX < UINTPTR_MAX
# define USE_LSB_TAG 1
# endif
# endif
# endif
#endif
#ifndef USE_LSB_TAG
# define USE_LSB_TAG 0
#endif
/* If we cannot use 8-byte alignment, make DECL_ALIGN a no-op. */
#ifndef DECL_ALIGN
# ifdef USE_LSB_TAG
# if USE_LSB_TAG
# error "USE_LSB_TAG used without defining DECL_ALIGN"
# endif
# define DECL_ALIGN(type, var) type var
......@@ -248,7 +252,7 @@ extern int suppress_checking EXTERNALLY_VISIBLE;
#else
# define LISP_INT_TAG Lisp_Int0
# define case_Lisp_Int case Lisp_Int0: case Lisp_Int1
# ifdef USE_LSB_TAG
# if USE_LSB_TAG
# define LISP_INT1_TAG 4
# define LISP_STRING_TAG 1
# define LISP_INT_TAG_P(x) (((x) & 3) == 0)
......@@ -333,10 +337,6 @@ enum Lisp_Fwd_Type
#ifdef USE_LISP_UNION_TYPE
#ifndef WORDS_BIGENDIAN
/* Definition of Lisp_Object for little-endian machines. */
typedef
union Lisp_Object
{
......@@ -359,44 +359,13 @@ union Lisp_Object
}
Lisp_Object;
#else /* If WORDS_BIGENDIAN */
typedef
union Lisp_Object
{
/* Used for comparing two Lisp_Objects;
also, positive integers can be accessed fast this way. */
EMACS_INT i;
struct
{
ENUM_BF (Lisp_Type) type : GCTYPEBITS;
/* Use explicit signed, the signedness of a bit-field of type
int is implementation defined. */
signed EMACS_INT val : VALBITS;
} s;
struct
{
ENUM_BF (Lisp_Type) type : GCTYPEBITS;
EMACS_UINT val : VALBITS;
} u;
}
Lisp_Object;
#endif /* WORDS_BIGENDIAN */
#ifdef __GNUC__
static inline Lisp_Object
LISP_MAKE_RVALUE (Lisp_Object o)
{
return o;
}
#else
/* This is more portable to pre-C99 non-GCC compilers, but for
backwards compatibility GCC still accepts an old GNU extension
which caused this to only generate a warning. */
#define LISP_MAKE_RVALUE(o) (0 ? (o) : (o))
#endif
#define LISP_INITIALLY_ZERO {0}
#else /* USE_LISP_UNION_TYPE */
......@@ -404,6 +373,7 @@ LISP_MAKE_RVALUE (Lisp_Object o)
typedef EMACS_INT Lisp_Object;
#define LISP_MAKE_RVALUE(o) (0+(o))
#define LISP_INITIALLY_ZERO 0
#endif /* USE_LISP_UNION_TYPE */
/* In the size word of a vector, this bit means the vector has been marked. */
......@@ -467,7 +437,7 @@ enum pvec_type
/* Return a perfect hash of the Lisp_Object representation. */
#define XHASH(a) (a)
#ifdef USE_LSB_TAG
#if USE_LSB_TAG
#define TYPEMASK ((((EMACS_INT) 1) << GCTYPEBITS) - 1)
#define XTYPE(a) ((enum Lisp_Type) ((a) & TYPEMASK))
......@@ -542,12 +512,12 @@ enum pvec_type
#define XINT(a) ((EMACS_INT) (a).s.val)
#define XUINT(a) ((EMACS_UINT) (a).u.val)
#ifdef USE_LSB_TAG
#if USE_LSB_TAG
# define XSET(var, vartype, ptr) \
(eassert ((((uintptr_t) (ptr)) & ((1 << GCTYPEBITS) - 1)) == 0), \
(var).u.val = ((uintptr_t) (ptr)) >> GCTYPEBITS, \
(var).u.type = ((char) (vartype)))
(eassert (((uintptr_t) (ptr) & ((1 << GCTYPEBITS) - 1)) == 0), \
(var).u.val = (uintptr_t) (ptr) >> GCTYPEBITS, \
(var).u.type = (vartype))
/* Some versions of gcc seem to consider the bitfield width when issuing
the "cast to pointer from integer of different size" warning, so the
......@@ -556,14 +526,8 @@ enum pvec_type
#else /* !USE_LSB_TAG */
/* For integers known to be positive, XFASTINT provides fast retrieval
and XSETFASTINT provides fast storage. This takes advantage of the
fact that Lisp_Int is 0. */
# define XFASTINT(a) ((a).i + 0)
# define XSETFASTINT(a, b) ((a).i = (b))
# define XSET(var, vartype, ptr) \
(((var).s.val = ((intptr_t) (ptr))), ((var).s.type = ((char) (vartype))))
((var).s.val = (intptr_t) (ptr), (var).s.type = (vartype))
#ifdef DATA_SEG_BITS
/* DATA_SEG_BITS forces extra bits to be or'd in with any pointers
......@@ -575,12 +539,14 @@ enum pvec_type
#endif /* !USE_LSB_TAG */
#if __GNUC__ >= 2 && defined (__OPTIMIZE__)
#define make_number(N) \
(__extension__ ({ Lisp_Object _l; _l.s.val = (N); _l.s.type = Lisp_Int; _l; }))
#else
extern Lisp_Object make_number (EMACS_INT);
#endif
static inline Lisp_Object
make_number (EMACS_INT n)
{
Lisp_Object o;
o.s.val = n;
o.s.type = Lisp_Int;
return o;
}
#endif /* USE_LISP_UNION_TYPE */
......
......@@ -34,7 +34,7 @@ extern int etext;
#endif
extern char *start_of_data (void);
#if defined USE_LSB_TAG || UINTPTR_MAX <= VAL_MAX
#if USE_LSB_TAG || UINTPTR_MAX <= VAL_MAX
#define EXCEEDS_LISP_PTR(ptr) 0
#elif defined DATA_SEG_BITS
#define EXCEEDS_LISP_PTR(ptr) \
......
......@@ -114,7 +114,7 @@ get_data_end (void)
return data_region_end;
}
#if !defined (USE_LISP_UNION_TYPE) && !defined (USE_LSB_TAG)
#if !defined USE_LISP_UNION_TYPE && !USE_LSB_TAG
static char *
allocate_heap (void)
{
......@@ -259,7 +259,7 @@ init_heap (void)
exit (1);
}
#if !defined (USE_LISP_UNION_TYPE) && !defined (USE_LSB_TAG)
#if !defined USE_LISP_UNION_TYPE && !USE_LSB_TAG
/* Ensure that the addresses don't use the upper tag bits since
the Lisp type goes there. */
if (((unsigned long) data_region_base & ~VALMASK) != 0)
......
......@@ -132,7 +132,7 @@ static int xfont_check (FRAME_PTR, struct font *);
struct font_driver xfont_driver =
{
0, /* Qx */
LISP_INITIALLY_ZERO, /* Qx */
0, /* case insensitive */
xfont_get_cache,
xfont_list,
......
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