[Bug #21103] Fix local variable index calculation with forwarding

Forwarding argument is optimized not to packed when no other arguments
and an internal object refers values before it.  This size is decided
at called time, calculate the local variable index from the fixed end
point.

proc.c

@@ -414,11 +414,11 @@ get_local_variable_ptr(const rb_env_t **envp, ID lid)
             }
 
             const rb_iseq_t *iseq = env->iseq;
-            unsigned int i;
 
             VM_ASSERT(rb_obj_is_iseq((VALUE)iseq));
 
-            for (i=0; i<ISEQ_BODY(iseq)->local_table_size; i++) {
+            const unsigned int local_table_size = ISEQ_BODY(iseq)->local_table_size;
+            for (unsigned int i=0; i<local_table_size; i++) {
                 if (ISEQ_BODY(iseq)->local_table[i] == lid) {
                     if (ISEQ_BODY(iseq)->local_iseq == iseq &&
                             ISEQ_BODY(iseq)->param.flags.has_block &&
@@ -431,7 +431,9 @@ get_local_variable_ptr(const rb_env_t **envp, ID lid)
                     }
 
                     *envp = env;
-                    return &env->env[i];
+                    unsigned int last_lvar = env->env_size+VM_ENV_INDEX_LAST_LVAR
+                        - 1 /* errinfo */;
+                    return &env->env[last_lvar - (local_table_size - i)];
                 }
             }
         }

test/ruby/test_method.rb

@@ -1439,6 +1439,46 @@ class TestMethod < Test::Unit::TestCase
     def foo
       a = b = c = a = b = c = 12345
     end
+
+    def binding_noarg
+      a = a = 12345
+      binding
+    end
+
+    def binding_one_arg(x)
+      a = a = 12345
+      binding
+    end
+
+    def binding_optargs(x, y=42)
+      a = a = 12345
+      binding
+    end
+
+    def binding_anyargs(*x)
+      a = a = 12345
+      binding
+    end
+
+    def binding_keywords(x: 42)
+      a = a = 12345
+      binding
+    end
+
+    def binding_anykeywords(**x)
+      a = a = 12345
+      binding
+    end
+
+    def binding_forwarding(...)
+      a = a = 12345
+      binding
+    end
+
+    def binding_forwarding1(x, ...)
+      a = a = 12345
+      binding
+    end
   end
 
   def test_to_proc_binding
@@ -1457,6 +1497,66 @@ class TestMethod < Test::Unit::TestCase
     assert_equal([:bar, :foo], b.local_variables.sort, bug11012)
   end
 
+  def test_method_binding
+    c = C.new
+
+    b = c.binding_noarg
+    assert_equal(12345, b.local_variable_get(:a))
+
+    b = c.binding_one_arg(0)
+    assert_equal(12345, b.local_variable_get(:a))
+    assert_equal(0, b.local_variable_get(:x))
+
+    b = c.binding_anyargs()
+    assert_equal(12345, b.local_variable_get(:a))
+    assert_equal([], b.local_variable_get(:x))
+    b = c.binding_anyargs(0)
+    assert_equal(12345, b.local_variable_get(:a))
+    assert_equal([0], b.local_variable_get(:x))
+    b = c.binding_anyargs(0, 1)
+    assert_equal(12345, b.local_variable_get(:a))
+    assert_equal([0, 1], b.local_variable_get(:x))
+
+    b = c.binding_optargs(0)
+    assert_equal(12345, b.local_variable_get(:a))
+    assert_equal(0, b.local_variable_get(:x))
+    assert_equal(42, b.local_variable_get(:y))
+    b = c.binding_optargs(0, 1)
+    assert_equal(12345, b.local_variable_get(:a))
+    assert_equal(0, b.local_variable_get(:x))
+    assert_equal(1, b.local_variable_get(:y))
+
+    b = c.binding_keywords()
+    assert_equal(12345, b.local_variable_get(:a))
+    assert_equal(42, b.local_variable_get(:x))
+    b = c.binding_keywords(x: 102)
+    assert_equal(12345, b.local_variable_get(:a))
+    assert_equal(102, b.local_variable_get(:x))
+
+    b = c.binding_anykeywords()
+    assert_equal(12345, b.local_variable_get(:a))
+    assert_equal({}, b.local_variable_get(:x))
+    b = c.binding_anykeywords(foo: 999)
+    assert_equal(12345, b.local_variable_get(:a))
+    assert_equal({foo: 999}, b.local_variable_get(:x))
+
+    b = c.binding_forwarding()
+    assert_equal(12345, b.local_variable_get(:a))
+    b = c.binding_forwarding(0)
+    assert_equal(12345, b.local_variable_get(:a))
+    b = c.binding_forwarding(0, 1)
+    assert_equal(12345, b.local_variable_get(:a))
+    b = c.binding_forwarding(foo: 42)
+    assert_equal(12345, b.local_variable_get(:a))
+
+    b = c.binding_forwarding1(987)
+    assert_equal(12345, b.local_variable_get(:a))
+    assert_equal(987, b.local_variable_get(:x))
+    b = c.binding_forwarding1(987, 654)
+    assert_equal(12345, b.local_variable_get(:a))
+    assert_equal(987, b.local_variable_get(:x))
+  end
+
   MethodInMethodClass_Setup = -> do
     remove_const :MethodInMethodClass if defined? MethodInMethodClass