1berry/ruby
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

__builtin_alloca_with_align for optimal memory access

Browse Source 
ALLOCA_N takes type arugment.  It is natural that the returned
value to be used as an array of type, thus type-aligned.
Luckily GCC has a builtin to tell compiler such alignment info.
This should generate beter instructions.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61830 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This commit is contained in:
shyouhei 2018-01-15 02:35:19 +00:00
parent 39cfa67b4f
commit df9a70900a
2 changed files with 9 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
configure.ac
View File

@ -2493,6 +2493,7 @@ AC_CACHE_CHECK([for $1], AS_TR_SH(rb_cv_builtin_$1),
AS_IF([test "${AS_TR_SH(rb_cv_builtin_$1)}" != no], [
AC_DEFINE(AS_TR_CPP(HAVE_BUILTIN_$1))
])])
RUBY_CHECK_BUILTIN_FUNC(__builtin_alloca_with_align, [__builtin_alloca_with_align(1, 4096)])
RUBY_CHECK_BUILTIN_FUNC(__builtin_assume_aligned, [__builtin_assume_aligned((void*)32, 32)])
RUBY_CHECK_BUILTIN_FUNC(__builtin_bswap16, [__builtin_bswap16(0)])
RUBY_CHECK_BUILTIN_FUNC(__builtin_bswap32, [__builtin_bswap32(0)])

8
include/ruby/ruby.h
View File

@ -1595,7 +1595,15 @@ rb_num2char_inline(VALUE x)
#define ZALLOC(type) RB_ZALLOC(type)
#define REALLOC_N(var,type,n) RB_REALLOC_N(var,type,n)
#ifdef HAVE_BUILTIN___BUILTIN_ALLOCA_WITH_ALIGN
/* I don't know why but __builtin_alloca_with_align's second argument
takes bits rather than bytes. */
#define ALLOCA_N(type, n) \
(type*)__builtin_alloca_with_align((sizeof(type)*(n)), \
sizeof(type) * CHAR_BIT)
#else
#define ALLOCA_N(type,n) ((type*)alloca(sizeof(type)*(n)))
#endif
void *rb_alloc_tmp_buffer(volatile VALUE *store, long len) RUBY_ATTR_ALLOC_SIZE((2));
void *rb_alloc_tmp_buffer_with_count(volatile VALUE *store, size_t len,size_t count) RUBY_ATTR_ALLOC_SIZE((2,3));