Basically, this makes the structure of buffer-local values and object
forwarding explicit in the type of Lisp_Symbols rather than use
special Lisp_Objects for that. This tends to lead to slightly more
verbose code, but is more C-like, simpler, and makes it easier to make
sure we handled all cases, among other things by letting the compiler
help us check it.
* lisp.h (enum Lisp_Misc_Type, union Lisp_Misc):
Removing forwarding objects.
(enum Lisp_Fwd_Type, enum symbol_redirect, union Lisp_Fwd): New types.
(struct Lisp_Symbol): Make the various forms of variable-forwarding
explicit rather than hiding them inside Lisp_Object "values".
(XFWDTYPE): New macro.
(XINTFWD, XBOOLFWD, XOBJFWD, XKBOARD_OBJFWD): Redefine.
(XBUFFER_LOCAL_VALUE): Remove.
(SYMBOL_VAL, SYMBOL_ALIAS, SYMBOL_BLV, SYMBOL_FWD, SET_SYMBOL_VAL)
(SET_SYMBOL_ALIAS, SET_SYMBOL_BLV, SET_SYMBOL_FWD): New macros.
(SYMBOL_VALUE, SET_SYMBOL_VALUE): Remove.
(struct Lisp_Intfwd, struct Lisp_Boolfwd, struct Lisp_Objfwd)
(struct Lisp_Buffer_Objfwd, struct Lisp_Kboard_Objfwd):
Remove the Lisp_Misc_* header.
(struct Lisp_Buffer_Local_Value): Redefine.
(BLV_FOUND, SET_BLV_FOUND, BLV_VALUE, SET_BLV_VALUE): New macros.
(struct Lisp_Misc_Any): Add filler to get the right size.
(struct Lisp_Free): Use struct Lisp_Misc_Any rather than struct
Lisp_Intfwd.
(DEFVAR_LISP, DEFVAR_LISP_NOPRO, DEFVAR_BOOL, DEFVAR_INT)
(DEFVAR_KBOARD): Allocate a forwarding object.
* data.c (do_blv_forwarding, store_blv_forwarding): New macros.
(let_shadows_global_binding_p): New function.
(union Lisp_Val_Fwd): New type.
(make_blv): New function.
(swap_in_symval_forwarding, indirect_variable, do_symval_forwarding)
(store_symval_forwarding, swap_in_global_binding, Fboundp)
(swap_in_symval_forwarding, find_symbol_value, Fset)
(let_shadows_buffer_binding_p, set_internal, default_value)
(Fset_default, Fmake_variable_buffer_local, Fmake_local_variable)
(Fkill_local_variable, Fmake_variable_frame_local)
(Flocal_variable_p, Flocal_variable_if_set_p)
(Fvariable_binding_locus):
* xdisp.c (select_frame_for_redisplay):
* lread.c (Fintern, Funintern, init_obarray, defvar_int)
(defvar_bool, defvar_lisp_nopro, defvar_lisp, defvar_kboard):
* frame.c (store_frame_param):
* eval.c (Fdefvaralias, Fuser_variable_p, specbind, unbind_to):
* bytecode.c (Fbyte_code) <varref, varset>: Adapt to the new symbol
value structure.
* buffer.c (PER_BUFFER_SYMBOL): Move from buffer.h.
(clone_per_buffer_values): Only adjust markers into the current buffer.
(reset_buffer_local_variables): PER_BUFFER_IDX is never -2.
(Fbuffer_local_value, set_buffer_internal_1)
(swap_out_buffer_local_variables):
Adapt to the new symbol value structure.
(DEFVAR_PER_BUFFER): Allocate a Lisp_Buffer_Objfwd object.
(defvar_per_buffer): Take a new arg for the fwd object.
(buffer_lisp_local_variables): Return a proper alist (different fix
for bug#4138).
* alloc.c (Fmake_symbol): Use SET_SYMBOL_VAL.
(Fgarbage_collect): Don't handle buffer_defaults specially.
(mark_object): Handle new symbol value structure rather than the old
special Lisp_Misc_* objects.
(gc_sweep) <symbols>: Free also the buffer-local-value objects.
* term.c (set_tty_color_mode):
* bidi.c (bidi_initialize): Don't access the ->value field directly.
* buffer.h (PER_BUFFER_VAR_OFFSET): Don't bother with
a buffer_local_flags.
* print.c (print_object): Get rid of impossible forwarding objects.
coding.c (decode_coding_emacs_mule): Fixup pointers to buffer
text that could be relocated inside the call to emacs_mule_char.
(emacs_mule_char): Use CODING_DECODE_CHAR instead of DECODE_CHAR.
(CODING_DECODE_CHAR): Add a comment describing its purpose.
(CODING_ISO_EXTSEGMENT_LEN, CODING_ISO_EMBEDDED_UTF_8): New macros.
(MAX_ANNOTATION_LENGTH): Defined to 5.
(ADD_COMPOSITION_DATA): New arg nbytes.
(emacs_mule_char): New arg cmp_status.
(DECODE_EMACS_MULE_COMPOSITION_CHAR): Delete it.
(DECODE_EMACS_MULE_COMPOSITION_RULE_20): New arg c.
(DECODE_EMACS_MULE_COMPOSITION_RULE_21): New arg c.
(DECODE_EMACS_MULE_21_COMPOSITION): Delete the arg c.
(DECODE_EMACS_MULE_20_RELATIVE_COMPOSITION): Likewise.
(DECODE_EMACS_MULE_20_RULEBASE_COMPOSITION): Likewise.
(DECODE_EMACS_MULE_COMPOSITION_START): New macro.
(EMACS_MULE_COMPOSITION_END): New macro.
(emacs_mule_finish_composition): New function.
(EMACS_MULE_MAYBE_FINISH_COMPOSITION): New macro.
(decode_coding_emacs_mule): Avoid long looking ahead while
handling composition.
(DECODE_COMPOSITION_RULE): Argument changed to rule and nbytes.
(ENCODE_COMPOSITION_RULE): New macro.
(finish_composition): New function.
(MAYBE_FINISH_COMPOSITION): Call finish_composition.
(DECODE_COMPOSITION_START): New implementation.
(DECODE_COMPOSITION_END): Likewise.
(STORE_COMPOSITION_RULE): New macro.
(decode_coding_iso_2022): Avoid long looking ahead while handling
composition, CTEXT extended segment, and embedded UTF-8.
(setup_coding_system): For a coding of type iso-2022, reset
CODING_ISO_EXTSEGMENT_LEN (coding) and
CODING_ISO_EMBEDDED_UTF_8 (coding).
(get_translation): Delete arguments last_block, from_nchars,
to_nchars. Callers changed.
(produce_chars): Don't modify charbuf. Adjusted for the change of
get_translation.
(produce_composition): Adjusted for the new annotation sequence.
(handle_composition_annotation): Likewise.
(consume_chars): Adjusted for the change of get_translation.
(inhibit_null_byte_detection): New variable.
(detect_coding, detect_coding_system): Don't pay attention to null bytes if
inhibit_null_byte_detection is non-zero.
(syms_of_coding) <inhibit-null-byte-detection>: Declare and document.
<inhibit-iso-escape-detection>: Doc fix.
