PredictableCodeSizeScope checks the expected size now.

src/assembler.cc

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // All Rights Reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 // - Redistributions of source code must retain the above copyright notice,
 // this list of conditions and the following disclaimer.
 //
@@ skipping 134 matching lines @@
         buffer_size_ == kMinimalBufferSize) {
       isolate()->set_assembler_spare_buffer(buffer_);
     } else {
       DeleteArray(buffer_);
     }
   }
 }
 
 
 // -----------------------------------------------------------------------------
+// Implementation of PredictableCodeSizeScope
+
+PredictableCodeSizeScope::PredictableCodeSizeScope(AssemblerBase* assembler,
+                                                   int expected_size)
+    : assembler_(assembler),
+      expected_size_(expected_size),
+      start_offset_(assembler->pc_offset()),
+      old_value_(assembler->predictable_code_size()) {
+  assembler_->set_predictable_code_size(true);
+}
+
+
+PredictableCodeSizeScope::~PredictableCodeSizeScope() {
+  // TODO(svenpanne) Remove the 'if' when everything works.
+  if (expected_size_ >= 0) {
+    CHECK_EQ(expected_size_, assembler_->pc_offset() - start_offset_);
+  }
+  assembler_->set_predictable_code_size(old_value_);
+}
+
+
+// -----------------------------------------------------------------------------
 // Implementation of Label
 
 int Label::pos() const {
   if (pos_ < 0) return -pos_ - 1;
   if (pos_ > 0) return  pos_ - 1;
   UNREACHABLE();
   return 0;
 }
 
 
@@ skipping 1266 matching lines @@
     assembler_->RecordRelocInfo(RelocInfo::POSITION, state_.current_position);
     state_.written_position = state_.current_position;
     written = true;
   }
 
   // Return whether something was written.
   return written;
 }
 
 } }  // namespace v8::internal