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[generator.c] use a conditional to select SIMD implementation rather than pointer #923

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Merged
byroot merged 2 commits into from
Jan 14, 2026
+33 −21
Merged

[generator.c] use a conditional to select SIMD implementation rather than pointer #923

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4809fc4
use a conditional to select SIMD implementation rather than pointer
samyron Jan 13, 2026
8699df4
initialize search.chunk_end to silence a warning about it being poten…
samyron Jan 14, 2026
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54 changes: 33 additions & 21 deletions ext/json/ext/generator/generator.c
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Original file line number Diff line number Diff line change
Expand Up @@ -63,6 +63,8 @@ struct generate_json_data {
long depth;
};

static SIMD_Implementation simd_impl;

static VALUE cState_from_state_s(VALUE self, VALUE opts);
static VALUE cState_partial_generate(VALUE self, VALUE obj, generator_func, VALUE io);
static void generate_json(FBuffer *buffer, struct generate_json_data *data, VALUE obj);
Expand Down Expand Up @@ -155,8 +157,6 @@ static const unsigned char escape_table_basic[256] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
};

static unsigned char (*search_escape_basic_impl)(search_state *);

static inline unsigned char search_escape_basic(search_state *search)
{
while (search->ptr < search->end) {
Expand Down Expand Up @@ -212,11 +212,39 @@ ALWAYS_INLINE(static) void escape_UTF8_char_basic(search_state *search)
* Everything else (should be UTF-8) is just passed through and
* appended to the result.
*/


#if defined(HAVE_SIMD_NEON)
static inline unsigned char search_escape_basic_neon(search_state *search);
#elif defined(HAVE_SIMD_SSE2)
static inline unsigned char search_escape_basic_sse2(search_state *search);
#endif

static inline unsigned char search_escape_basic(search_state *search);

static inline void convert_UTF8_to_JSON(search_state *search)
{
while (search_escape_basic_impl(search)) {
#ifdef HAVE_SIMD
#if defined(HAVE_SIMD_NEON)
while (search_escape_basic_neon(search)) {
escape_UTF8_char_basic(search);
}
#elif defined(HAVE_SIMD_SSE2)
if (simd_impl == SIMD_SSE2) {
while (search_escape_basic_sse2(search)) {
escape_UTF8_char_basic(search);
}
return;
}
while (search_escape_basic(search)) {
escape_UTF8_char_basic(search);
}
#endif
#else
while (search_escape_basic(search)) {
escape_UTF8_char_basic(search);
}
#endif /* HAVE_SIMD */
}

static inline void escape_UTF8_char(search_state *search, unsigned char ch_len)
Expand Down Expand Up @@ -1091,6 +1119,7 @@ static void raw_generate_json_string(FBuffer *buffer, struct generate_json_data
search.matches_mask = 0;
search.has_matches = false;
search.chunk_base = NULL;
search.chunk_end = NULL;
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@samyron samyron Jan 14, 2026

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Now that this is being inlined on gcc it emitted a warning about chunk_end potentially being uninitialized when compiling on Linux.

#endif /* HAVE_SIMD */

switch (rb_enc_str_coderange(obj)) {
Expand Down Expand Up @@ -2181,22 +2210,5 @@ void Init_generator(void)

rb_require("json/ext/generator/state");


switch (find_simd_implementation()) {
#ifdef HAVE_SIMD
#ifdef HAVE_SIMD_NEON
case SIMD_NEON:
search_escape_basic_impl = search_escape_basic_neon;
break;
#endif /* HAVE_SIMD_NEON */
#ifdef HAVE_SIMD_SSE2
case SIMD_SSE2:
search_escape_basic_impl = search_escape_basic_sse2;
break;
#endif /* HAVE_SIMD_SSE2 */
#endif /* HAVE_SIMD */
default:
search_escape_basic_impl = search_escape_basic;
break;
}
simd_impl = find_simd_implementation();
}