Assert the GVL is held when performing various rb_ functions.

[Feature #20877]

Author: ioquatix

array.c

@@ -27,6 +27,7 @@
 #include "probes.h"
 #include "ruby/encoding.h"
 #include "ruby/st.h"
+#include "ruby/thread.h"
 #include "ruby/util.h"
 #include "vm_core.h"
 #include "builtin.h"
@@ -521,6 +522,8 @@ rb_ary_set_shared(VALUE ary, VALUE shared_root)
 static inline void
 rb_ary_modify_check(VALUE ary)
 {
+    RUBY_ASSERT(ruby_thread_has_gvl_p());
+
     rb_check_frozen(ary);
     ary_verify(ary);
 }
@@ -705,6 +708,8 @@ empty_ary_alloc(VALUE klass)
 static VALUE
 ary_new(VALUE klass, long capa)
 {
+    RUBY_ASSERT(ruby_thread_has_gvl_p());
+
     VALUE ary;
 
     if (capa < 0) {

common.mk

@@ -2276,6 +2276,7 @@ array.$(OBJEXT): {$(VPATH)}rubyparser.h
 array.$(OBJEXT): {$(VPATH)}shape.h
 array.$(OBJEXT): {$(VPATH)}st.h
 array.$(OBJEXT): {$(VPATH)}subst.h
+array.$(OBJEXT): {$(VPATH)}thread.h
 array.$(OBJEXT): {$(VPATH)}thread_$(THREAD_MODEL).h
 array.$(OBJEXT): {$(VPATH)}thread_native.h
 array.$(OBJEXT): {$(VPATH)}util.h
@@ -17547,6 +17548,7 @@ string.$(OBJEXT): {$(VPATH)}shape.h
 string.$(OBJEXT): {$(VPATH)}st.h
 string.$(OBJEXT): {$(VPATH)}string.c
 string.$(OBJEXT): {$(VPATH)}subst.h
+string.$(OBJEXT): {$(VPATH)}thread.h
 string.$(OBJEXT): {$(VPATH)}thread_$(THREAD_MODEL).h
 string.$(OBJEXT): {$(VPATH)}thread_native.h
 string.$(OBJEXT): {$(VPATH)}util.h

string.c

@@ -42,6 +42,7 @@
 #include "probes.h"
 #include "ruby/encoding.h"
 #include "ruby/re.h"
+#include "ruby/thread.h"
 #include "ruby/util.h"
 #include "ruby_assert.h"
 #include "vm_sync.h"
@@ -2586,6 +2587,8 @@ rb_check_lockedtmp(VALUE str)
 static inline void
 str_modifiable(VALUE str)
 {
+    RUBY_ASSERT(ruby_thread_has_gvl_p());
+
     if (RB_UNLIKELY(FL_ANY_RAW(str, STR_UNMODIFIABLE_MASK))) {
         if (CHILLED_STRING_P(str)) {
             CHILLED_STRING_MUTATED(str);
@@ -2612,6 +2615,8 @@ str_dependent_p(VALUE str)
 static inline int
 str_independent(VALUE str)
 {
+    RUBY_ASSERT(ruby_thread_has_gvl_p());
+
     if (RB_UNLIKELY(FL_ANY_RAW(str, STR_DEPENDANT_MASK))) {
         str_modifiable(str);
         return !str_dependent_p(str);
@@ -2622,6 +2627,8 @@ str_independent(VALUE str)
 static void
 str_make_independent_expand(VALUE str, long len, long expand, const int termlen)
 {
+    RUBY_ASSERT(ruby_thread_has_gvl_p());
+
     char *ptr;
     char *oldptr;
     long capa = len + expand;
@@ -2664,6 +2671,8 @@ rb_str_modify(VALUE str)
 void
 rb_str_modify_expand(VALUE str, long expand)
 {
+    RUBY_ASSERT(ruby_thread_has_gvl_p());
+
     int termlen = TERM_LEN(str);
     long len = RSTRING_LEN(str);
 
@@ -2727,6 +2736,8 @@ rb_must_asciicompat(VALUE str)
 VALUE
 rb_string_value(volatile VALUE *ptr)
 {
+    RUBY_ASSERT(ruby_thread_has_gvl_p());
+
     VALUE s = *ptr;
     if (!RB_TYPE_P(s, T_STRING)) {
         s = rb_str_to_str(s);
@@ -3286,6 +3297,8 @@ rb_str_locktmp_ensure(VALUE str, VALUE (*func)(VALUE), VALUE arg)
 void
 rb_str_set_len(VALUE str, long len)
 {
+    RUBY_ASSERT(ruby_thread_has_gvl_p());
+
     long capa;
     const int termlen = TERM_LEN(str);