mirror/gcc
1
0
Fork 0
mirror of https://github.com/gcc-mirror/gcc.git synced 2024-11-21 13:40:47 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

libcpp: Use constexpr for _cpp_trigraph_map initialization for C++14

Browse Source 
The _cpp_trigraph_map initialization used to be done for C99+ using
designated initializers, but can't be done that way for C++ because
the designated initializer support in C++ as array designators are just
an extension there and don't allow skipping anything nor going backwards.

But, we can get the same effect using C++14 constexpr constructor.
With the following patch we get rid of the runtime initialization
and the array can be in .rodata.

2024-10-07  Jakub Jelinek  <jakub@redhat.com>

	* internal.h (_cpp_trigraph_map_s): New type for C++14 or later.
	(_cpp_trigraph_map_d): New variable for C++14 or later.
	(_cpp_trigraph_map): Define to _cpp_trigraph_map_d.map for C++14 or
	later.
	* init.cc (init_trigraph_map): Define to nothing for C++14 or later.
	(TRIGRAPH_MAP, END, s): Define differently for C++14 or later.
This commit is contained in:
Jakub Jelinek 2024-10-07 21:25:22 +02:00 committed by Jakub Jelinek
parent c0002a675a
commit e4c0595ec4
2 changed files with 17 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
libcpp/init.cc
View File

@ -41,8 +41,8 @@ static void read_original_directory (cpp_reader *);
static void post_options (cpp_reader *);
/* If we have designated initializers (GCC >2.7) these tables can be
initialized, constant data. Otherwise, they have to be filled in at
runtime. */
initialized, constant data. Similarly for C++14 and later.
Otherwise, they have to be filled in at runtime. */
#if HAVE_DESIGNATED_INITIALIZERS
#define init_trigraph_map() /* Nothing. */
@ -52,6 +52,15 @@ __extension__ const uchar _cpp_trigraph_map[UCHAR_MAX + 1] = {
#define END };
#define s(p, v) [p] = v,
#elif __cpp_constexpr >= 201304L
#define init_trigraph_map() /* Nothing. */
#define TRIGRAPH_MAP \
constexpr _cpp_trigraph_map_s::_cpp_trigraph_map_s () : map {} {
#define END } \
constexpr _cpp_trigraph_map_s _cpp_trigraph_map_d;
#define s(p, v) map[p] = v;
#else
#define TRIGRAPH_MAP uchar _cpp_trigraph_map[UCHAR_MAX + 1] = { 0 }; \

6
libcpp/internal.h
View File

@ -668,6 +668,12 @@ struct cpp_embed_params
compiler that supports C99. */
#if HAVE_DESIGNATED_INITIALIZERS
extern const unsigned char _cpp_trigraph_map[UCHAR_MAX + 1];
#elif __cpp_constexpr >= 201304L
extern const struct _cpp_trigraph_map_s {
unsigned char map[UCHAR_MAX + 1];
constexpr _cpp_trigraph_map_s ();
} _cpp_trigraph_map_d;
#define _cpp_trigraph_map _cpp_trigraph_map_d.map
#else
extern unsigned char _cpp_trigraph_map[UCHAR_MAX + 1];
#endif