Add flag specifying whether patch signature mismatches can be ignored.

runtime/vm/object.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 48 matching lines @@
 DEFINE_FLAG(bool, show_internal_names, false,
     "Show names of internal classes (e.g. \"OneByteString\") in error messages "
     "instead of showing the corresponding interface names (e.g. \"String\")");
 DEFINE_FLAG(bool, throw_on_javascript_int_overflow, false,
     "Throw an exception when the result of an integer calculation will not "
     "fit into a javascript integer.");
 DEFINE_FLAG(bool, trace_cha, false, "Trace CHA operations");
 DEFINE_FLAG(bool, use_field_guards, true, "Guard field cids.");
 DEFINE_FLAG(bool, use_lib_cache, true, "Use library name cache");
 DEFINE_FLAG(bool, trace_field_guards, false, "Trace changes in field's cids.");
+DEFINE_FLAG(bool, ignore_patch_signature_mismatch, false,
+            "Ignore patch file member signature mismatch.");
 
 DECLARE_FLAG(charp, coverage_dir);
 DECLARE_FLAG(bool, load_deferred_eagerly);
 DECLARE_FLAG(bool, show_invisible_frames);
 DECLARE_FLAG(bool, trace_compiler);
 DECLARE_FLAG(bool, trace_deoptimization);
 DECLARE_FLAG(bool, trace_deoptimization_verbose);
 DECLARE_FLAG(bool, write_protect_code);
 
 
@@ skipping 2809 matching lines @@
     func = patch.LookupFunction(member_name);
     if (func.IsNull()) {
       // Non-patched function is preserved, all patched functions are added in
       // the loop below.
       // However, an implicitly created constructor should not be preserved if
       // the patch provides a constructor or a factory. Wait for now.
       if (orig_func.raw() != orig_implicit_ctor.raw()) {
         new_functions.Add(orig_func);
       }
     } else if (func.UserVisibleSignature() !=
-               orig_func.UserVisibleSignature()) {
+               orig_func.UserVisibleSignature()
+               && !FLAG_ignore_patch_signature_mismatch) {
       // Compare user visible signatures to ignore different implicit parameters
       // when patching a constructor with a factory.
       *error = LanguageError::NewFormatted(
           *error,  // No previous error.
           Script::Handle(patch.script()),
           func.token_pos(),
           Report::kError,
           Heap::kNew,
           "signature mismatch: '%s'", member_name.ToCString());
       return false;
@@ skipping 18582 matching lines @@
   return tag_label.ToCString();
 }
 
 
 void UserTag::PrintJSONImpl(JSONStream* stream, bool ref) const {
   Instance::PrintJSONImpl(stream, ref);
 }
 
 
 }  // namespace dart