[pull] master from ruby:master

.github/workflows/modgc.yml

@@ -131,6 +131,10 @@ jobs:
           echo "TESTS=${TESTS}" >> $GITHUB_ENV
         if: ${{ matrix.test_task == 'check' && matrix.skipped_tests }}
 
+      - name: Set timeout scale
+        run: echo "RUBY_TEST_TIMEOUT_SCALE=10" >> $GITHUB_ENV # subprocess assertion timeouts flake on slower/contended macOS runners, especially with the slower MMTk GC
+        if: ${{ contains(matrix.os, 'macos') }}
+
       - name: Set up Launchable
         id: launchable
         uses: ./.github/actions/launchable/setup

LEGAL

@@ -714,10 +714,9 @@ mentioned below.
 
     {MIT License}[rdoc-ref:@MIT+License]
 
-[ext/json/vendor/ryu.h]
-  This file is adapted from the Ryu algorithm by Ulf Adams https://github.com/ulfjack/ryu.
-  It is dual-licensed under {Apache License 2.0}[rdoc-ref:@Apache+License+2.0] OR
-  {Boost Software License 1.0}[rdoc-ref:@Boost+Software+License+1.0].
+[ext/json/vendor/fast_float_parser.h]
+  This file is adapted from the Fast Float C++ library by The fast_float authors https://github.com/fastfloat/fast_float
+  It is licensed under the MIT License
 
 [ext/psych]
 [test/psych]

ext/json/parser/depend

@@ -177,6 +177,6 @@ parser.o: $(hdrdir)/ruby/subst.h
 parser.o: $(srcdir)/../fbuffer/fbuffer.h
 parser.o: $(srcdir)/../json.h
 parser.o: $(srcdir)/../simd/simd.h
-parser.o: $(srcdir)/../vendor/ryu.h
+parser.o: $(srcdir)/../vendor/fast_float_parser.h
 parser.o: parser.c
 # AUTOGENERATED DEPENDENCIES END

ext/json/parser/extconf.rb

@@ -8,6 +8,31 @@
 have_func("rb_hash_bulk_insert", "ruby.h") # Missing on TruffleRuby
 have_func("ruby_xfree_sized", "ruby.h") # RUBY_VERSION >= 4.1
 
+def have_builtin_func(name, check_expr, opt = "", &b)
+  checking_for checking_message(name.funcall_style, nil, opt) do
+    if try_compile(<<SRC, opt, &b)
+int foo;
+int main() { #{check_expr}; return 0; }
+SRC
+      $defs.push(format("-DHAVE_BUILTIN_%s", name.tr_cpp))
+      true
+    else
+      false
+    end
+  end
+end
+
+have_builtin_func("__builtin_clzll", "__builtin_clzll(0)")
+
+if have_header("x86intrin.h")
+  have_func("_lzcnt_u64", "x86intrin.h")
+end
+
+if have_header("intrin.h")
+  have_func("__lzcnt64", "intrin.h")
+  have_func("_BitScanReverse64", "intrin.h")
+end
+
 if RUBY_ENGINE == "ruby"
   have_const("RUBY_TYPED_EMBEDDABLE", "ruby.h") # RUBY_VERSION >= 3.3
 end

ext/json/parser/parser.c

@@ -1,5 +1,5 @@
 #include "../json.h"
-#include "../vendor/ryu.h"
+#include "../vendor/fast_float_parser.h"
 #include "../simd/simd.h"
 
 static VALUE mJSON, eNestingError, eParserError, Encoding_UTF_8;
@@ -1111,13 +1111,11 @@ static inline VALUE json_decode_float(JSON_ParserConfig *config, uint64_t mantis
         return rb_float_new(negative ? -0.0 : 0.0);
     }
 
-    // Fall back to rb_cstr_to_dbl for potential subnormals (rare edge case)
-    // Ryu has rounding issues with subnormals around 1e-310 (< 2.225e-308)
-    if (RB_UNLIKELY(mantissa_digits > 17 || mantissa_digits + exponent < -307)) {
+    if (RB_UNLIKELY(mantissa_digits > 18 || mantissa_digits + exponent < -307)) {
         return json_decode_large_float(start, end - start);
     }
 
-    return DBL2NUM(ryu_s2d_from_parts(mantissa, mantissa_digits, (int32_t)exponent, negative));
+    return DBL2NUM(ffp_s2d(exponent, mantissa, negative));
 }
 
 static inline VALUE json_decode_array(JSON_ParserState *state, JSON_ParserConfig *config, long count)
@@ -1543,6 +1541,8 @@ ALWAYS_INLINE(static) bool json_parse_any(JSON_ParserState *state, JSON_ParserCo
         json_eat_whitespace(state, config);
 
         VALUE value;
+        const char *value_start = state->cursor;
+
         switch (peek(state)) {
             case 'n':
                 json_match_keyword(state, "null", 0);
@@ -1578,13 +1578,12 @@ ALWAYS_INLINE(static) bool json_parse_any(JSON_ParserState *state, JSON_ParserCo
                 break;
 
             case '-': {
-                const char *start = state->cursor;
                 state->cursor++;
 
-                value = json_parse_number(state, config, true, start);
+                value = json_parse_number(state, config, true, value_start);
 
                 if (RB_UNLIKELY(UNDEF_P(value) && config->allow_nan && peek(state) == 'I')) {
-                    state->cursor = start;
+                    state->cursor = value_start;
                     json_match_keyword(state, "-Infinity", 1);
                     value = CMinusInfinity;
                     break;
@@ -1593,51 +1592,49 @@ ALWAYS_INLINE(static) bool json_parse_any(JSON_ParserState *state, JSON_ParserCo
                 // Top level numbers are ambiguous when parsing streams, we can't
                 // know if we parsed all the digits if we hit EOS.
                 if (RB_UNLIKELY(resumable && eos(state))) {
-                    state->cursor = start;
+                    state->cursor = value_start;
                     return false;
                 }
 
                 if (RB_UNLIKELY(UNDEF_P(value))) {
-                    raise_syntax_error_at("invalid number: %s", state, start);
+                    raise_syntax_error_at("invalid number: %s", state, value_start);
                 }
                 break;
             }
 
             case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': {
-                const char *start = state->cursor;
-
-                value = json_parse_number(state, config, false, start);
+                value = json_parse_number(state, config, false, value_start);
 
                 // Top level numbers are ambiguous when parsing streams, we can't
                 // know if we parsed all the digits if we hit EOS.
                 if (RB_UNLIKELY(resumable && eos(state))) {
-                    state->cursor = start;
+                    state->cursor = value_start;
                     return false;
                 }
 
                 if (RB_UNLIKELY(UNDEF_P(value))) {
-                    raise_syntax_error_at("invalid number: %s", state, start);
+                    raise_syntax_error_at("invalid number: %s", state, value_start);
                 }
                 break;
             }
 
             case '"': {
                 // %r{\A"[^"\\\t\n\x00]*(?:\\[bfnrtu\\/"][^"\\]*)*"}
-                const char *start = state->cursor;
                 value = json_parse_string(state, config, false);
 
                 if (RB_UNLIKELY(UNDEF_P(value))) {
                     bool is_eos = eos(state);
-                    if (resumable) {
-                        state->cursor = start;
+                    if (resumable && is_eos) {
+                        state->cursor = value_start;
+                        return false;
                     }
                     raise_parse_error("unexpected end of input, expected closing \"", state, is_eos);
                 }
                 break;
             }
 
             case '[': {
-                const char *start = state->cursor++;
+                state->cursor++;
                 json_eat_whitespace(state, config);
 
                 const char next = peek(state);
@@ -1646,7 +1643,7 @@ ALWAYS_INLINE(static) bool json_parse_any(JSON_ParserState *state, JSON_ParserCo
                     value = json_decode_array(state, config, 0);
                     break;
                 } else if (resumable && next == 0) {
-                    state->cursor = start;
+                    state->cursor = value_start;
                     return false;
                 }
 
@@ -1666,8 +1663,6 @@ ALWAYS_INLINE(static) bool json_parse_any(JSON_ParserState *state, JSON_ParserCo
             }
 
             case '{': {
-                const char *object_start_cursor = state->cursor;
-
                 state->cursor++;
                 json_eat_whitespace(state, config);
 
@@ -1676,7 +1671,7 @@ ALWAYS_INLINE(static) bool json_parse_any(JSON_ParserState *state, JSON_ParserCo
                     value = json_decode_object(state, config, 0);
                     break;
                 } else if (resumable && eos(state)) {
-                    state->cursor = object_start_cursor;
+                    state->cursor = value_start;
                     return false;
                 }
 
@@ -1690,7 +1685,7 @@ ALWAYS_INLINE(static) bool json_parse_any(JSON_ParserState *state, JSON_ParserCo
                     .type = JSON_FRAME_OBJECT,
                     .phase = JSON_PHASE_OBJECT_KEY,
                     .value_stack_head = state->value_stack->head,
-                    .start_offset = object_start_cursor - state->start,
+                    .start_offset = value_start - state->start,
                 });
                 goto JSON_PHASE_OBJECT_KEY;
             }