From 322548180d01ce99dcb8ecb3c36f2a9261554657 Mon Sep 17 00:00:00 2001
From: Matt Valentine-House <matt@eightbitraptor.com>
Date: Thu, 31 Aug 2023 15:35:56 +0100
Subject: [PATCH] Prevent rb_gc_mark_values from pinning objects

This is an internal only function not exposed to the C extension API.
It's only use so far is from rb_vm_mark, where it's used to mark the
values in the vm->trap_list.cmd array.

There shouldn't be any reason why these cannot move.

This commit allows them to move by updating their references during the
reference updating step of compaction.

To do this we've introduced another internal function
rb_gc_update_values as a partner to rb_gc_mark_values.

This allows us to refactor rb_gc_mark_values to not pin
---
 gc.c          | 8 +++++++-
 internal/gc.h | 1 +
 vm.c          | 2 ++
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/gc.c b/gc.c
index 59c507369e..d780bb0613 100644
--- a/gc.c
+++ b/gc.c
@@ -6348,7 +6348,7 @@ rb_gc_mark_values(long n, const VALUE *values)
     rb_objspace_t *objspace = &rb_objspace;
 
     for (i=0; i<n; i++) {
-        gc_mark_and_pin(objspace, values[i]);
+        gc_mark(objspace, values[i]);
     }
 }
 
@@ -10135,6 +10135,12 @@ gc_update_values(rb_objspace_t *objspace, long n, VALUE *values)
     }
 }
 
+void
+rb_gc_update_values(long n, VALUE *values)
+{
+    gc_update_values(&rb_objspace, n, values);
+}
+
 static bool
 moved_or_living_object_strictly_p(rb_objspace_t *objspace, VALUE obj)
 {
diff --git a/internal/gc.h b/internal/gc.h
index 7e0942a76a..be40a7a2f7 100644
--- a/internal/gc.h
+++ b/internal/gc.h
@@ -274,6 +274,7 @@ void rb_gc_verify_internal_consistency(void);
 size_t rb_obj_gc_flags(VALUE, ID[], size_t);
 void rb_gc_mark_values(long n, const VALUE *values);
 void rb_gc_mark_vm_stack_values(long n, const VALUE *values);
+void rb_gc_update_values(long n, VALUE *values);
 void *ruby_sized_xrealloc(void *ptr, size_t new_size, size_t old_size) RUBY_ATTR_RETURNS_NONNULL RUBY_ATTR_ALLOC_SIZE((2));
 void *ruby_sized_xrealloc2(void *ptr, size_t new_count, size_t element_size, size_t old_count) RUBY_ATTR_RETURNS_NONNULL RUBY_ATTR_ALLOC_SIZE((2, 3));
 void ruby_sized_xfree(void *x, size_t size);
diff --git a/vm.c b/vm.c
index 56442231cb..4b2b1ad344 100644
--- a/vm.c
+++ b/vm.c
@@ -2743,6 +2743,8 @@ rb_vm_update_references(void *ptr)
 
         rb_gc_update_tbl_refs(vm->overloaded_cme_table);
 
+        rb_gc_update_values(RUBY_NSIG, vm->trap_list.cmd);
+
         if (vm->coverages) {
             vm->coverages = rb_gc_location(vm->coverages);
             vm->me2counter = rb_gc_location(vm->me2counter);