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			59 lines
		
	
	
		
			1.9 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			59 lines
		
	
	
		
			1.9 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
| // Copyright 2015 the V8 project authors. All rights reserved.
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| // Use of this source code is governed by a BSD-style license that can be
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| // found in the LICENSE file.
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| 
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| // Flags: --allow-natives-syntax
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| 
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| function Migrator(o) {
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|   return o.foo;
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| }
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| function Loader(o) {
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|   return o[0];
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| }
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| 
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| var first_smi_array = [1];
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| var second_smi_array = [2];
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| var first_object_array = ["first"];
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| var second_object_array = ["string"];
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| 
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| assertTrue(%HasSmiElements(first_smi_array));
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| assertTrue(%HasSmiElements(second_smi_array));
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| assertTrue(%HasObjectElements(first_object_array));
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| assertTrue(%HasObjectElements(second_object_array));
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| 
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| // Prepare identical transition chains for smi and object arrays.
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| first_smi_array.foo = 0;
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| second_smi_array.foo = 0;
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| first_object_array.foo = 0;
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| second_object_array.foo = 0;
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| 
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| // Collect type feedback for not-yet-deprecated original object array map.
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| for (var i = 0; i < 3; i++) Migrator(second_object_array);
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| 
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| // Blaze a migration trail for smi array maps.
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| // This marks the migrated smi array map as a migration target.
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| first_smi_array.foo = 0.5;
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| print(second_smi_array.foo);
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| 
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| // Deprecate original object array map.
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| // Use TryMigrate from deferred optimized code to migrate second object array.
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| first_object_array.foo = 0.5;
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| %OptimizeFunctionOnNextCall(Migrator);
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| Migrator(second_object_array);
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| 
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| // |second_object_array| now erroneously has a smi map.
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| // Optimized code assuming smi elements will expose this.
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| 
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| for (var i = 0; i < 3; i++) Loader(second_smi_array);
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| %OptimizeFunctionOnNextCall(Loader);
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| assertEquals("string", Loader(second_object_array));
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| 
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| // Any of the following checks will also fail:
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| assertTrue(%HasObjectElements(second_object_array));
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| assertFalse(%HasSmiElements(second_object_array));
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| assertTrue(%HaveSameMap(first_object_array, second_object_array));
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| assertFalse(%HaveSameMap(first_smi_array, second_object_array));
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| 
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| %ClearFunctionFeedback(Loader);
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| %ClearFunctionFeedback(Migrator);
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