Implement cref on opt_getconstant_path

lib/ruby_vm/mjit/insn_compiler.rb

@@ -457,9 +457,26 @@ module RubyVM::MJIT
       end
 
       if ice.ic_cref # with cref
-        # Not supported yet
-        asm.incr_counter(:optgetconst_cref)
-        return CantCompile
+        # Cache is keyed on a certain lexical scope. Use the interpreter's cache.
+        side_exit = side_exit(jit, ctx)
+
+        # Call function to verify the cache. It doesn't allocate or call methods.
+        asm.mov(C_ARGS[0], ic.to_i)
+        asm.mov(C_ARGS[1], [CFP, C.rb_control_frame_t.offsetof(:ep)])
+        asm.call(C.rb_vm_ic_hit_p)
+
+        # Check the result. SysV only specifies one byte for _Bool return values,
+        # so it's important we only check one bit to ignore the higher bits in the register.
+        asm.test(C_RET, 1)
+        asm.jz(counted_exit(side_exit, :optgetconst_cache_miss))
+
+        asm.mov(:rax, ic.to_i) # inline_cache
+        asm.mov(:rax, [:rax, C.iseq_inline_constant_cache.offsetof(:entry)]) # ic_entry
+        asm.mov(:rax, [:rax, C.iseq_inline_constant_cache_entry.offsetof(:value)]) # ic_entry_val
+
+        # Push ic->entry->value
+        stack_top = ctx.stack_push
+        asm.mov(stack_top, :rax)
       else # without cref
         # TODO: implement this
         # Optimize for single ractor mode.

mjit_c.h

@@ -179,6 +179,7 @@ MJIT_RUNTIME_COUNTERS(
 
     optgetconst_not_cached,
     optgetconst_cref,
+    optgetconst_cache_miss,
 
     setivar_frozen,
     setivar_not_heap,

mjit_c.rb

@@ -344,6 +344,13 @@ module RubyVM::MJIT # :nodoc: all
       }
     end
 
+    def rb_vm_ic_hit_p
+      Primitive.cstmt! %{
+        extern bool rb_vm_ic_hit_p(IC ic, const VALUE *reg_ep);
+        return SIZET2NUM((size_t)rb_vm_ic_hit_p);
+      }
+    end
+
     #========================================================================================
     #
     # Old stuff
@@ -1427,6 +1434,7 @@ module RubyVM::MJIT # :nodoc: all
       optaref_send: [CType::Immediate.parse("size_t"), Primitive.cexpr!("OFFSETOF((*((struct rb_mjit_runtime_counters *)NULL)), optaref_send)")],
       optgetconst_not_cached: [CType::Immediate.parse("size_t"), Primitive.cexpr!("OFFSETOF((*((struct rb_mjit_runtime_counters *)NULL)), optgetconst_not_cached)")],
       optgetconst_cref: [CType::Immediate.parse("size_t"), Primitive.cexpr!("OFFSETOF((*((struct rb_mjit_runtime_counters *)NULL)), optgetconst_cref)")],
+      optgetconst_cache_miss: [CType::Immediate.parse("size_t"), Primitive.cexpr!("OFFSETOF((*((struct rb_mjit_runtime_counters *)NULL)), optgetconst_cache_miss)")],
       setivar_frozen: [CType::Immediate.parse("size_t"), Primitive.cexpr!("OFFSETOF((*((struct rb_mjit_runtime_counters *)NULL)), setivar_frozen)")],
       setivar_not_heap: [CType::Immediate.parse("size_t"), Primitive.cexpr!("OFFSETOF((*((struct rb_mjit_runtime_counters *)NULL)), setivar_not_heap)")],
       setivar_megamorphic: [CType::Immediate.parse("size_t"), Primitive.cexpr!("OFFSETOF((*((struct rb_mjit_runtime_counters *)NULL)), setivar_megamorphic)")],