Finer-grained constant cache invalidation (take 2)

This commit reintroduces finer-grained constant cache invalidation.
After 8008fb7 got merged, it was causing issues on token-threaded
builds (such as on Windows).

The issue was that when you're iterating through instruction sequences
and using the translator functions to get back the instruction structs,
you're either using `rb_vm_insn_null_translator` or
`rb_vm_insn_addr2insn2` depending if it's a direct-threading build.
`rb_vm_insn_addr2insn2` does some normalization to always return to
you the non-trace version of whatever instruction you're looking at.
`rb_vm_insn_null_translator` does not do that normalization.

This means that when you're looping through the instructions if you're
trying to do an opcode comparison, it can change depending on the type
of threading that you're using. This can be very confusing. So, this
commit creates a new translator function
`rb_vm_insn_normalizing_translator` to always return the non-trace
version so that opcode comparisons don't have to worry about different
configurations.

[Feature #18589]

1 files changed, 7 insertions, 0 deletions

diff --git a/include/ruby/internal/intern/vm.h b/include/ruby/internal/intern/vm.h
index eb53c7a356..76af796b54 100644
--- a/include/ruby/internal/intern/vm.h
+++ b/include/ruby/internal/intern/vm.h
@@ -253,6 +253,13 @@ void rb_undef_alloc_func(VALUE klass);
 rb_alloc_func_t rb_get_alloc_func(VALUE klass);
 
 /**
+ * Clears the inline constant caches associated with a particular ID. Extension
+ * libraries should not bother with such things. Just forget about this API (or
+ * even, the presence of constant caches).
+ */
+void rb_clear_constant_cache_for_id(ID id);
+
+/**
  * Resembles `alias`.
  *
  * @param[out]  klass            Where to define an alias.