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Don't use GNU extensions for SCM_MAKE_CHAR macro

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Since the contents of SCM_MAKE_CHAR are evaluated more than once,
don't use it in situations where this could cause side-effects.

        * libguile/vm-i-system.c (make-char8): avoid side-effects with
        SCM_MAKE_CHAR call

        * libguile/chars.h (SCM_MAKE_CHAR): modified
This commit is contained in:
Michael Gran 2009-08-01 10:15:20 -07:00
parent 64bad3f5a8
commit 4c402b889e
2 changed files with 11 additions and 5 deletions
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8
libguile/chars.h
View file

@ -37,10 +37,10 @@ typedef scm_t_int32 scm_t_wchar;
#define SCM_CHARP(x) (SCM_ITAG8(x) == scm_tc8_char)
#define SCM_CHAR(x) ((scm_t_wchar)SCM_ITAG8_DATA(x))
#define SCM_MAKE_CHAR(x) ({scm_t_int32 _x = (x); \
_x < 0 \
? SCM_MAKE_ITAG8((scm_t_bits)(unsigned char)_x, scm_tc8_char) \
: SCM_MAKE_ITAG8((scm_t_bits)_x, scm_tc8_char);})
#define SCM_MAKE_CHAR(x) \
(x < 0 \
? SCM_MAKE_ITAG8 ((scm_t_bits) (unsigned char) x, scm_tc8_char) \
: SCM_MAKE_ITAG8 ((scm_t_bits) x, scm_tc8_char))
#define SCM_CODEPOINT_MAX (0x10ffff)
#define SCM_IS_UNICODE_CHAR(c) \

8
libguile/vm-i-system.c
View file

@ -171,7 +171,13 @@ VM_DEFINE_INSTRUCTION (15, make_uint64, "make-uint64", 8, 0, 1)
VM_DEFINE_INSTRUCTION (16, make_char8, "make-char8", 1, 0, 1)
{
PUSH (SCM_MAKE_CHAR (FETCH ()));
scm_t_uint8 v = 0;
v = FETCH ();
PUSH (SCM_MAKE_CHAR (v));
/* Don't simplify this to PUSH (SCM_MAKE_CHAR (FETCH ())). The
contents of SCM_MAKE_CHAR may be evaluated more than once,
resulting in a double fetch. */
NEXT;
}