From bfe3e0a23e66d16bfcaae6890bdd764dec0525f2 Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Tue, 12 Jun 2012 17:26:40 -0700 Subject: [PATCH] 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. --- src/ChangeLog | 24 +++++++++++ src/alloc.c | 65 +++++++++------------------- src/data.c | 4 +- src/emacs.c | 4 +- src/ftfont.c | 2 +- src/lisp.h | 108 ++++++++++++++++------------------------------- src/mem-limits.h | 2 +- src/w32heap.c | 4 +- src/xfont.c | 2 +- 9 files changed, 91 insertions(+), 124 deletions(-) diff --git a/src/ChangeLog b/src/ChangeLog index cd5c96cf36..8a32572907 100644 --- a/src/ChangeLog +++ b/src/ChangeLog @@ -1,3 +1,27 @@ +2012-06-13 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. + 2012-06-12 Glenn Morris * s/gnu-kfreebsd.h, s/hpux11.h, s/openbsd.h, s/sol2-10.h: Remove files. diff --git a/src/alloc.c b/src/alloc.c index 7051af9b99..1223f0bc13 100644 --- a/src/alloc.c +++ b/src/alloc.c @@ -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); diff --git a/src/data.c b/src/data.c index defcd06a2e..4449977dbe 100644 --- a/src/data.c +++ b/src/data.c @@ -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; diff --git a/src/emacs.c b/src/emacs.c index 8ffacdab1c..bc3f918e2a 100644 --- a/src/emacs.c +++ b/src/emacs.c @@ -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; diff --git a/src/ftfont.c b/src/ftfont.c index 5545b4b4ae..bfce7425af 100644 --- a/src/ftfont.c +++ b/src/ftfont.c @@ -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, diff --git a/src/lisp.h b/src/lisp.h index 9e108d950d..0e9b0c63c7 100644 --- a/src/lisp.h +++ b/src/lisp.h @@ -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 */ diff --git a/src/mem-limits.h b/src/mem-limits.h index 1fd53b472f..01b0e6ebb2 100644 --- a/src/mem-limits.h +++ b/src/mem-limits.h @@ -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) \ diff --git a/src/w32heap.c b/src/w32heap.c index da8579896f..00572b20ae 100644 --- a/src/w32heap.c +++ b/src/w32heap.c @@ -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) diff --git a/src/xfont.c b/src/xfont.c index bde76c0ba3..cc06e27fe0 100644 --- a/src/xfont.c +++ b/src/xfont.c @@ -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, -- 2.20.1