Implement correct semantics of Boolean Conversion

runtime/vm/intermediate_language_x64.cc

Index: runtime/vm/intermediate_language_x64.cc
===================================================================
--- runtime/vm/intermediate_language_x64.cc	(revision 42124)
+++ runtime/vm/intermediate_language_x64.cc	(working copy)
@@ -23,6 +23,8 @@
 namespace dart {
 
 DECLARE_FLAG(bool, emit_edge_counters);
+DECLARE_FLAG(bool, enable_asserts);

[srdjan, 2014/12/05 00:49:28]

please sort alphabetically (also in other architectures)

[hausner, 2014/12/05 20:36:10]

They are already in alphabetical order.

+DECLARE_FLAG(bool, enable_type_checks);
 DECLARE_FLAG(int, optimization_counter_threshold);
 DECLARE_FLAG(bool, propagate_ic_data);
 DECLARE_FLAG(bool, throw_on_javascript_int_overflow);
@@ -329,11 +331,18 @@
   // Call the runtime if the object is not bool::true or bool::false.
   ASSERT(locs->always_calls());
   Label done;
-  __ CompareObject(reg, Bool::True(), PP);
-  __ j(EQUAL, &done, Assembler::kNearJump);
-  __ CompareObject(reg, Bool::False(), PP);
-  __ j(EQUAL, &done, Assembler::kNearJump);
 
+  if (FLAG_enable_type_checks) {
+    __ CompareObject(reg, Bool::True(), PP);
+    __ j(EQUAL, &done, Assembler::kNearJump);
+    __ CompareObject(reg, Bool::False(), PP);
+    __ j(EQUAL, &done, Assembler::kNearJump);
+  } else {
+    ASSERT(FLAG_enable_asserts);
+    __ CompareObject(reg, Object::null_instance(), PP);
+    __ j(NOT_EQUAL, &done, Assembler::kNearJump);
+  }
+
   __ pushq(reg);  // Push the source object.
   compiler->GenerateRuntimeCall(token_pos,
                                 deopt_id,