On 05/01/2015 06:56 PM, David Malcolm wrote:
This patch eliminates the union in struct line_map in favor of
a simple class hierarchy, making struct line_map a base class,
with line_map_ordinary and line_map_macro subclasses.
The patch eliminates all usage of linemap_check_ordinary and
linemap_check_macro from line-map.h, updating return types and
signatures throughout libcpp and gcc's usage of it to use the
appropriate subclasses.
This moves the checking of linemap kind from run-time to
compile-time, and also implicitly documents everywhere where
the code is expecting an ordinary map vs a macro map vs
either kind of map. I believe it makes the code significantly
simpler: most of the accessor functions in line-map.h become
trivial field-lookups.
I attemped to use templates for maps_info, but was stymied by
gengtype, so in the end I simply split it manually into
maps_info_ordinary and maps_info_macro. In theory it's just
a vec<>, but vec.h is in gcc, and thus not available
for use from libcpp.
In a similar vein, gcc/is-a.h is presumably not usable
from within libcpp. If it were, there would be the following
rough equivalences:
--------------------------------- --------------------------------
line-map.h is-a.h
--------------------------------- --------------------------------
linemap_check_ordinary (m) as_a <line_map_ordinary *> (m)
linemap_check_macro (m) as_a <line_map_macro *> (m)
linemap_macro_expansion_map_p (m) (M ? is_a <line_map_macro *> (m)
: false)
--------------------------------- --------------------------------
There are numerous places in libcpp that offset a
line_map * using array notation to get the next/prev line_map of the
same kind, e.g.:
MAP_START_LOCATION (&cached[1])
which breaks due to the different sizes of line_map vs its subclasses.
On x86_64 host, before:
(gdb) p sizeof(line_map)
$1 = 40
after:
(gdb) p sizeof(line_map)
$1 = 8
(gdb) p sizeof(line_map_ordinary)
$2 = 32
(gdb) p sizeof(line_map_macro)
$3 = 40
Tracking down all of these array-based offsets to use a pointer to the
appropriate subclass (and thus use the correct offset) was rather
involved, but I believe the patch fixes them all now.
(the patch thus also gives a very modest saving of 8 bytes per ordinary
line map).
I've tried to use the naming convention "ord_map" and "macro_map"
whenever the typesystem ensures we're dealing with such a map,
wherever this is doable without needing to touch lines of code that
would otherwise not need touching by the patch.
gcc/ChangeLog:
* diagnostic.c (diagnostic_report_current_module): Strengthen
local "new_map" from const line_map * to
const line_map_ordinary *.
* genmatch.c (error_cb): Likewise for local "map".
(output_line_directive): Likewise for local "map".
* input.c (expand_location_1): Likewise for local "map".
Pass NULL rather than &map to
linemap_unwind_to_first_non_reserved_loc, since the value is never
read from there, and the value written back not read from here.
(is_location_from_builtin_token): Strengthen local "map" from
const line_map * to const line_map_ordinary *.
(dump_location_info): Strengthen locals "map" from
line_map *, one to const line_map_ordinary *, the other
to const line_map_macro *.
* tree-diagnostic.c (loc_map_pair): Strengthen field "map" from
const line_map * to const line_map_macro *.
(maybe_unwind_expanded_macro_loc): Add a call to
linemap_check_macro when writing to the "map" field of the
loc_map_pair.
Introduce local const line_map_ordinary * "ord_map", using it in
place of "map" in the part of the function where we know we have
an ordinary map. Strengthen local "m" from const line_map * to
const line_map_ordinary *.
gcc/ada/ChangeLog:
* gcc-interface/trans.c (Sloc_to_locus1): Strenghthen local "map"
from line_map * to line_map_ordinary *.
gcc/c-family/ChangeLog:
* c-common.h (fe_file_change): Strengthen param from
const line_map * to const line_map_ordinary *.
(pp_file_change): Likewise.
* c-lex.c (fe_file_change): Likewise.
(cb_define): Use linemap_check_ordinary when invoking
SOURCE_LINE.
(cb_undef): Likewise.
* c-opts.c (c_finish_options): Use linemap_check_ordinary when
invoking cb_file_change.
(c_finish_options): Likewise.
(push_command_line_include): Likewise.
(cb_file_change): Strengthen param "new_map" from
const line_map * to const line_map_ordinary *.
* c-ppoutput.c (cb_define): Likewise for local "map".
(pp_file_change): Likewise for param "map" and local "from".
gcc/fortran/ChangeLog:
* cpp.c (maybe_print_line): Strengthen local "map" from
const line_map * to const line_map_ordinary *.
(cb_file_change): Likewise for param "map" and local "from".
(cb_line_change): Likewise for local "map".
libcpp/ChangeLog:
* directives.c (do_line): Strengthen local "map" from
const line_map * to const line_map_ordinary *.
(do_linemarker): Likewise.
(_cpp_do_file_change): Assert that we're not dealing with
a macro map. Introduce local "ord_map" via a call to
linemap_check_ordinary, guarded within the check for
non-NULL. Use it for typesafety.
* files.c (cpp_make_system_header): Strengthen local "map" from
const line_map * to const line_map_ordinary *.
* include/cpplib.h (struct cpp_callbacks): Likewise for second
parameter of "file_change" callback.
* include/line-map.h (struct line_map): Convert from a struct
containing a union to a base class.
(struct line_map_ordinary): Convert to a subclass of line_map.
(struct line_map_macro): Likewise.
(linemap_check_ordinary): Strengthen return type from line_map *
to line_map_ordinary *, and add a const-variant.
(linemap_check_macro): New pair of functions.
(ORDINARY_MAP_STARTING_LINE_NUMBER): Strengthen param from
const line_map * to const line_map_ordinary *, eliminating call
to linemap_check_ordinary. Likewise for the non-const variant.
(ORDINARY_MAP_INCLUDER_FILE_INDEX): Likewise.
(ORDINARY_MAP_IN_SYSTEM_HEADER_P): Likewise.
(ORDINARY_MAP_NUMBER_OF_COLUMN_BITS): Likewise.
(ORDINARY_MAP_FILE_NAME): Likewise.
(MACRO_MAP_MACRO): Strengthen param from const line_map * to
const line_map_macro *. Likewise for the non-const variant.
(MACRO_MAP_NUM_MACRO_TOKENS): Likewise.
(MACRO_MAP_LOCATIONS): Likewise.
(MACRO_MAP_EXPANSION_POINT_LOCATION): Likewise.
(struct maps_info): Replace with...
(struct maps_info_ordinary):...this and...
(struct maps_info_macro): ...this.
(struct line_maps): Convert fields "info_ordinary" and
"info_macro" to the above new structs.
(LINEMAPS_MAP_INFO): Delete both functions.
(LINEMAPS_MAPS): Likewise.
(LINEMAPS_ALLOCATED): Rewrite both variants to avoid using
LINEMAPS_MAP_INFO.
(LINEMAPS_USED): Likewise.
(LINEMAPS_CACHE): Likewise.
(LINEMAPS_MAP_AT): Likewise.
(LINEMAPS_ORDINARY_MAPS): Strengthen return type from line_map *
to line_map_ordinary *.
(LINEMAPS_ORDINARY_MAP_AT): Likewise.
(LINEMAPS_LAST_ORDINARY_MAP): Likewise.
(LINEMAPS_LAST_ALLOCATED_ORDINARY_MAP): Likewise.
(LINEMAPS_MACRO_MAPS): Strengthen return type from line_map * to
line_map_macro *.
(LINEMAPS_MACRO_MAP_AT): Likewise.
(LINEMAPS_LAST_MACRO_MAP): Likewise.
(LINEMAPS_LAST_ALLOCATED_MACRO_MAP): Likewise.
(linemap_map_get_macro_name): Strengthen param from
const line_map * to const line_map_macro *.
(SOURCE_LINE): Strengthen first param from const line_map * to
const line_map_ordinary *, removing call to
linemap_check_ordinary.
(SOURCE_COLUMN): Likewise.
(LAST_SOURCE_LINE_LOCATION): Likewise.
(LAST_SOURCE_LINE): Strengthen first param from const line_map *
to const line_map_ordinary *.
(LAST_SOURCE_COLUMN): Likewise.
(INCLUDED_FROM): Strengthen return type from line_map * to
line_map_ordinary *., and second param from const line_map *
to const line_map_ordinary *, removing call to
linemap_check_ordinary.
(MAIN_FILE_P): Strengthen param from const line_map * to
const line_map_ordinary *, removing call to
linemap_check_ordinary.
(linemap_position_for_line_and_column): Strengthen param from
const line_map * to const line_map_ordinary *.
(LINEMAP_FILE): Strengthen param from const line_map * to
const line_map_ordinary *, removing call to
linemap_check_ordinary.
(LINEMAP_LINE): Likewise.
(LINEMAP_SYSP): Likewise.
(linemap_resolve_location): Strengthen final param from
const line_map ** to const line_map_ordinary **.
* internal.h (CPP_INCREMENT_LINE): Likewise for local "map".
(linemap_enter_macro): Strengthen return type from
const line_map * to const line_map_macro *.
(linemap_add_macro_token): Likewise for first param.
* line-map.c (linemap_check_files_exited): Strengthen local "map"
from const line_map * to const line_map_ordinary *.
(new_linemap): Introduce local "map_size" and use it when
calculating how large the buffer should be. Rewrite based
on change of info_macro and info_ordinary into distinct types.
(linemap_add): Strengthen locals "map" and "from" from line_map *
to line_map_ordinary *.
(linemap_enter_macro): Strengthen return type from
const line_map * to const line_map_macro *, and local "map" from
line_map * to line_map_macro *.
(linemap_add_macro_token): Strengthen param "map" from
const line_map * to const line_map_macro *.
(linemap_line_start): Strengthen local "map" from line_map * to
line_map_ordinary *.
(linemap_position_for_column): Likewise.
(linemap_position_for_line_and_column): Strengthen first param
from const line_map * to const line_map_ordinary *.
(linemap_position_for_loc_and_offset): Strengthen local "map" from
const line_map * to const line_map_ordinary *.
(linemap_ordinary_map_lookup): Likewise for return type and locals
"cached" and "result".
(linemap_macro_map_lookup): Strengthen return type and locals
"cached" and "result" from const line_map * to
const line_map_macro *.
(linemap_macro_map_loc_to_exp_point): Likewise for param "map".
(linemap_macro_map_loc_to_def_point): Likewise.
(linemap_macro_map_loc_unwind_toward_spelling): Likewise.
(linemap_get_expansion_line): Strengthen local "map" from
const line_map * to const line_map_ordinary *.
(linemap_get_expansion_filename): Likewise.
(linemap_map_get_macro_name): Strengthen param from
const line_map * to const line_map_macro *.
(linemap_location_in_system_header_p): Add call to
linemap_check_ordinary in region guarded by
!linemap_macro_expansion_map_p. Introduce local "macro_map" via
linemap_check_macro in other region, using it in place of "map"
for typesafety.
(first_map_in_common_1): Add calls to linemap_check_macro.
(trace_include): Strengthen param "map" from const line_map * to
const line_map_ordinary *.
(linemap_macro_loc_to_spelling_point): Strengthen final param from
const line_map ** to const line_map_ordinary **. Replace a
C-style cast with a const_cast, and add calls to
linemap_check_macro and linemap_check_ordinary.
(linemap_macro_loc_to_def_point): Likewise.
(linemap_macro_loc_to_exp_point): Likewise.
(linemap_resolve_location): Strengthen final param from
const line_map ** to const line_map_ordinary **.
(linemap_unwind_toward_expansion): Introduce local "macro_map" via
a checked cast and use it in place of *map.
(linemap_unwind_to_first_non_reserved_loc): Strengthen local
"map1" from const line_map * to const line_map_ordinary *.
(linemap_expand_location): Introduce local "ord_map" via a checked
cast and use it in place of map.
(linemap_dump): Make local "map" const. Strengthen local
"includer_map" from line_map * to const line_map_ordinary *.
Introduce locals "ord_map" and "macro_map" via checked casts and
use them in place of "map" for typesafety.
(linemap_dump_location): Strengthen local "map" from
const line_map * to const line_map_ordinary *.
(linemap_get_file_highest_location): Update for elimination of
union.
(linemap_get_statistics): Strengthen local "cur_map" from
line_map * to const line_map_macro *. Update uses of sizeof to
use the appropriate line_map subclasses.
* macro.c (_cpp_warn_if_unused_macro): Add call to
linemap_check_ordinary.
(builtin_macro): Strengthen local "map" from const line_map * to
const line_map_macro *.
(enter_macro_context): Likewise.
(replace_args): Likewise.
(tokens_buff_put_token_to): Likewise for param "map".
(tokens_buff_add_token): Likewise.
---
@@ -158,7 +158,7 @@ expand_location_1 (source_location loc,
location (toward the expansion point) that is not reserved;
that is, the first location that is in real source code. */
loc = linemap_unwind_to_first_non_reserved_loc (line_table,
- loc, &map);
+ loc, NULL);
Is that really correct?
/* Return the map at a given index. */
inline line_map *
LINEMAPS_MAP_AT (const line_maps *set, bool map_kind, int index)
{
- return &(LINEMAPS_MAPS (set, map_kind)[index]);
+ if (map_kind)
+ return &set->info_macro.maps[index];
+ else
+ return &set->info_ordinary.maps[index];
}
I see this pattern repeated regularly. Any thoughts on how painful
it'll be to drop the map_kind argument and instead not vary the kind?
I just spot checked all the mechanical changes. Looks reasonable me to me.
Just need to sort out if the hunk with the call to l_u_t_f_n_r_l is
correct and get the pre-reqs installed and I think this is good to go.
Jeff
