[Emacs-diffs] Changes to emacs/src/lisp.h [lexbind]

[Miles Bader]

Index: emacs/src/lisp.h
diff -c emacs/src/lisp.h:1.423.2.13 emacs/src/lisp.h:1.423.2.14
*** emacs/src/lisp.h:1.423.2.13 Tue May 11 02:38:15 2004
--- emacs/src/lisp.h    Tue Jul  6 09:14:36 2004
***************
*** 284,307 ****
  #define BOOL_VECTOR_BITS_PER_CHAR 8
  
  /***** Select the tagging scheme.  *****/
  
  /* First, try and define DECL_ALIGN(type,var) which declares a static
     variable VAR of type TYPE with the added requirement that it be
     TYPEBITS-aligned. */
! #if defined USE_LSB_TAG && !defined DECL_ALIGN
  /* What compiler directive should we use for non-gcc compilers?  -stef  */
! # if defined (__GNUC__)
! #  define DECL_ALIGN(type, var) \
!     type __attribute__ ((__aligned__ (1 << GCTYPEBITS))) var
! # else
! #  error "USE_LSB_TAG used without defining DECL_ALIGN"
  # endif
  #endif
  
- #ifndef USE_LSB_TAG
  /* Just remove the alignment annotation if we don't use it.  */
! #undef DECL_ALIGN
! #define DECL_ALIGN(type, var) type var
  #endif
  
  
--- 284,336 ----
  #define BOOL_VECTOR_BITS_PER_CHAR 8
  
  /***** Select the tagging scheme.  *****/
+ /* There are basically two options that control the tagging scheme:
+    - NO_UNION_TYPE says that Lisp_Object should be an integer instead
+      of a union.
+    - USE_LSB_TAG means that we can assume the least 3 bits of pointers are
+      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.
+ 
+    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
+    on the few static Lisp_Objects used: all the defsubr as well
+    as the two special buffers buffer_defaults and buffer_local_symbols.  */
  
  /* First, try and define DECL_ALIGN(type,var) which declares a static
     variable VAR of type TYPE with the added requirement that it be
     TYPEBITS-aligned. */
! #ifndef DECL_ALIGN
! # ifndef MSDOS        /* MS-DOS doesn't currently support USE_LSB_TAG */
  /* What compiler directive should we use for non-gcc compilers?  -stef  */
! #  if defined (__GNUC__)
! #   define DECL_ALIGN(type, var) \
!      type __attribute__ ((__aligned__ (1 << GCTYPEBITS))) var
! #  endif
! # 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 MAC_OSX
! /* We also need to be able to specify mult-of-8 alignment on static vars.  */
! # if defined DECL_ALIGN
! /* We currently do not support USE_LSB_TAG with a union Lisp_Object.  */
! #  if defined NO_UNION_TYPE
! #   define USE_LSB_TAG
! #  endif
  # endif
  #endif
  
  /* Just remove the alignment annotation if we don't use it.  */
! #ifndef DECL_ALIGN
! # ifdef USE_LSB_TAG
! #  error "USE_LSB_TAG used without defining DECL_ALIGN"
! # endif
! # define DECL_ALIGN(type, var) type var
  #endif
  
  
***************
*** 2862,2867 ****
--- 2891,2900 ----
  extern void syms_of_indent P_ ((void));
  
  /* defined in frame.c */
+ #ifdef HAVE_WINDOW_SYSTEM
+ extern Lisp_Object Vx_resource_name;
+ extern Lisp_Object Vx_resource_class;
+ #endif /* HAVE_WINDOW_SYSTEM */
  extern Lisp_Object Qvisible;
  extern void store_frame_param P_ ((struct frame *, Lisp_Object, Lisp_Object));
  extern void store_in_alist P_ ((Lisp_Object *, Lisp_Object, Lisp_Object));
***************
*** 3084,3094 ****
  #ifdef HAVE_X_WINDOWS
  /* Defined in xfns.c */
  extern void syms_of_xfns P_ ((void));
! extern Lisp_Object Vx_resource_name;
! extern Lisp_Object Vx_resource_class;
  EXFUN (Fxw_display_color_p, 1);
  EXFUN (Fx_file_dialog, 4);
! #endif /* HAVE_X_WINDOWS */
  
  /* Defined in xsmfns.c */
  extern void syms_of_xsmfns P_ ((void));
--- 3117,3128 ----
  #ifdef HAVE_X_WINDOWS
  /* Defined in xfns.c */
  extern void syms_of_xfns P_ ((void));
! #endif /* HAVE_X_WINDOWS */
! #ifdef HAVE_WINDOW_SYSTEM
! /* Defined in xfns.c, w32fns.c, or macfns.c */
  EXFUN (Fxw_display_color_p, 1);
  EXFUN (Fx_file_dialog, 4);
! #endif /* HAVE_WINDOW_SYSTEM */
  
  /* Defined in xsmfns.c */
  extern void syms_of_xsmfns P_ ((void));
***************
*** 3114,3122 ****
  
  extern char *xstrdup P_ ((const char *));
  
- #ifndef USE_CRT_DLL
  extern char *egetenv P_ ((char *));
- #endif
  
  /* Set up the name of the machine we're running on.  */
  extern void init_system_name P_ ((void));
--- 3148,3154 ----