diff --git a/Source/JavaScriptCore/bytecode/BytecodeUseDef.h b/Source/JavaScriptCore/bytecode/BytecodeUseDef.h
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+++ b/Source/JavaScriptCore/bytecode/BytecodeUseDef.h
@@ -0,0 +1,413 @@
+/*
+ * Copyright (C) 2013 Apple 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:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+ * THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef BytecodeUseDef_h
+#define BytecodeUseDef_h
+
+#include "CodeBlock.h"
+
+namespace JSC {
+
+template<typename Functor>
+void computeUsesForBytecodeOffset(
+    CodeBlock* codeBlock, unsigned bytecodeOffset, Functor& functor)
+{
+    Interpreter* interpreter = codeBlock->vm()->interpreter;
+    Instruction* instructionsBegin = codeBlock->instructions().begin();
+    Instruction* instruction = &instructionsBegin[bytecodeOffset];
+    OpcodeID opcodeID = interpreter->getOpcodeID(instruction->u.opcode);
+    switch (opcodeID) {
+    // No uses.
+    case op_new_regexp:
+    case op_new_array_buffer:
+    case op_throw_static_error:
+    case op_debug:
+    case op_resolve_scope:
+    case op_pop_scope:
+    case op_jneq_ptr:
+    case op_new_func_exp:
+    case op_loop_hint:
+    case op_jmp:
+    case op_new_object:
+    case op_init_lazy_reg:
+    case op_get_callee:
+    case op_enter:
+    case op_catch:
+    case op_touch_entry:
+        return;
+    case op_new_func:
+    case op_new_captured_func:
+    case op_create_activation: 
+    case op_create_arguments:
+    case op_to_this:
+    case op_tear_off_activation:
+    case op_profile_will_call:
+    case op_profile_did_call:
+    case op_throw:
+    case op_push_with_scope:
+    case op_end:
+    case op_ret:
+    case op_jtrue:
+    case op_jfalse:
+    case op_jeq_null:
+    case op_jneq_null:
+    case op_dec:
+    case op_inc: {
+        functor(codeBlock, instruction, opcodeID, instruction[1].u.operand);
+        return;
+    }
+    case op_ret_object_or_this:
+    case op_jlesseq:
+    case op_jgreater:
+    case op_jgreatereq:
+    case op_jnless:
+    case op_jnlesseq:
+    case op_jngreater:
+    case op_jngreatereq:
+    case op_jless: {
+        functor(codeBlock, instruction, opcodeID, instruction[1].u.operand);
+        functor(codeBlock, instruction, opcodeID, instruction[2].u.operand);
+        return;
+    }
+    case op_put_by_val_direct:
+    case op_put_by_val: {
+        functor(codeBlock, instruction, opcodeID, instruction[1].u.operand);
+        functor(codeBlock, instruction, opcodeID, instruction[2].u.operand);
+        functor(codeBlock, instruction, opcodeID, instruction[3].u.operand);
+        return;
+    }
+    case op_put_by_index:
+    case op_put_by_id_replace:
+    case op_put_by_id_transition:
+    case op_put_by_id_transition_direct:
+    case op_put_by_id_transition_direct_out_of_line:
+    case op_put_by_id_transition_normal:
+    case op_put_by_id_transition_normal_out_of_line:
+    case op_put_by_id_generic:
+    case op_put_by_id_out_of_line:
+    case op_put_by_id:
+    case op_put_to_scope: {
+        functor(codeBlock, instruction, opcodeID, instruction[1].u.operand);
+        functor(codeBlock, instruction, opcodeID, instruction[3].u.operand);
+        return;
+    }
+    case op_put_getter_setter: {
+        functor(codeBlock, instruction, opcodeID, instruction[1].u.operand);
+        functor(codeBlock, instruction, opcodeID, instruction[3].u.operand);
+        functor(codeBlock, instruction, opcodeID, instruction[4].u.operand);
+        return;
+    }
+    case op_init_global_const_nop:
+    case op_init_global_const:
+    case op_push_name_scope:
+    case op_get_from_scope:
+    case op_to_primitive:
+    case op_get_by_id:
+    case op_get_by_id_out_of_line:
+    case op_get_by_id_self:
+    case op_get_by_id_proto:
+    case op_get_by_id_chain:
+    case op_get_by_id_getter_self:
+    case op_get_by_id_getter_proto:
+    case op_get_by_id_getter_chain:
+    case op_get_by_id_custom_self:
+    case op_get_by_id_custom_proto:
+    case op_get_by_id_custom_chain:
+    case op_get_by_id_generic:
+    case op_get_array_length:
+    case op_get_string_length:
+    case op_get_arguments_length:
+    case op_typeof:
+    case op_is_undefined:
+    case op_is_boolean:
+    case op_is_number:
+    case op_is_string:
+    case op_is_object:
+    case op_is_function:
+    case op_to_number:
+    case op_negate:
+    case op_neq_null:
+    case op_eq_null:
+    case op_not:
+    case op_mov:
+    case op_captured_mov:
+    case op_new_array_with_size:
+    case op_create_this:
+    case op_get_pnames:
+    case op_del_by_id: {
+        functor(codeBlock, instruction, opcodeID, instruction[2].u.operand);
+        return;
+    }
+    case op_get_by_val:
+    case op_get_argument_by_val:
+    case op_in:
+    case op_instanceof:
+    case op_check_has_instance:
+    case op_add:
+    case op_mul:
+    case op_div:
+    case op_mod:
+    case op_sub:
+    case op_lshift:
+    case op_rshift:
+    case op_urshift:
+    case op_bitand:
+    case op_bitxor:
+    case op_bitor:
+    case op_less:
+    case op_lesseq:
+    case op_greater:
+    case op_greatereq:
+    case op_nstricteq:
+    case op_stricteq:
+    case op_neq:
+    case op_eq:
+    case op_del_by_val: {
+        functor(codeBlock, instruction, opcodeID, instruction[2].u.operand);
+        functor(codeBlock, instruction, opcodeID, instruction[3].u.operand);
+        return;
+    }
+    case op_call_varargs: {
+        functor(codeBlock, instruction, opcodeID, instruction[2].u.operand);
+        functor(codeBlock, instruction, opcodeID, instruction[3].u.operand);
+        functor(codeBlock, instruction, opcodeID, instruction[4].u.operand);
+        return;
+    }
+    case op_next_pname: {
+        functor(codeBlock, instruction, opcodeID, instruction[2].u.operand);
+        functor(codeBlock, instruction, opcodeID, instruction[3].u.operand);
+        functor(codeBlock, instruction, opcodeID, instruction[4].u.operand);
+        functor(codeBlock, instruction, opcodeID, instruction[5].u.operand);
+        return;
+    }
+    case op_get_by_pname: {
+        functor(codeBlock, instruction, opcodeID, instruction[2].u.operand);
+        functor(codeBlock, instruction, opcodeID, instruction[3].u.operand);
+        functor(codeBlock, instruction, opcodeID, instruction[4].u.operand);
+        functor(codeBlock, instruction, opcodeID, instruction[5].u.operand);
+        functor(codeBlock, instruction, opcodeID, instruction[6].u.operand);
+        return;
+    }
+    case op_switch_string:
+    case op_switch_char:
+    case op_switch_imm: {
+        functor(codeBlock, instruction, opcodeID, instruction[3].u.operand);
+        return;
+    }
+    case op_new_array:
+    case op_strcat: {
+        int base = instruction[2].u.operand;
+        int count = instruction[3].u.operand;
+        for (int i = 0; i < count; i++)
+            functor(codeBlock, instruction, opcodeID, base - i);
+        return;
+    }
+    case op_construct:
+    case op_call_eval:
+    case op_call: {
+        functor(codeBlock, instruction, opcodeID, instruction[2].u.operand);
+        int argCount = instruction[3].u.operand;
+        int registerOffset = -instruction[4].u.operand;
+        int lastArg = registerOffset + CallFrame::thisArgumentOffset();
+        for (int i = opcodeID == op_construct ? 1 : 0; i < argCount; i++)
+            functor(codeBlock, instruction, opcodeID, lastArg + i);
+        return;
+    }
+    case op_tear_off_arguments: {
+        functor(codeBlock, instruction, opcodeID, instruction[1].u.operand);
+        functor(codeBlock, instruction, opcodeID, unmodifiedArgumentsRegister(VirtualRegister(instruction[1].u.operand)).offset());
+        functor(codeBlock, instruction, opcodeID, instruction[2].u.operand);
+        return;
+    }
+    default:
+        RELEASE_ASSERT_NOT_REACHED();
+        break;
+    }
+}
+
+template<typename Functor>
+void computeDefsForBytecodeOffset(CodeBlock* codeBlock, unsigned bytecodeOffset, Functor& functor)
+{
+    Interpreter* interpreter = codeBlock->vm()->interpreter;
+    Instruction* instructionsBegin = codeBlock->instructions().begin();
+    Instruction* instruction = &instructionsBegin[bytecodeOffset];
+    OpcodeID opcodeID = interpreter->getOpcodeID(instruction->u.opcode);
+    switch (opcodeID) {
+    // These don't define anything.
+    case op_init_global_const:
+    case op_init_global_const_nop:
+    case op_push_name_scope:
+    case op_push_with_scope:
+    case op_put_to_scope:
+    case op_pop_scope:
+    case op_end:
+    case op_profile_will_call:
+    case op_profile_did_call:
+    case op_throw:
+    case op_throw_static_error:
+    case op_debug:
+    case op_ret:
+    case op_ret_object_or_this:
+    case op_jmp:
+    case op_jtrue:
+    case op_jfalse:
+    case op_jeq_null:
+    case op_jneq_null:
+    case op_jneq_ptr:
+    case op_jless:
+    case op_jlesseq:
+    case op_jgreater:
+    case op_jgreatereq:
+    case op_jnless:
+    case op_jnlesseq:
+    case op_jngreater:
+    case op_jngreatereq:
+    case op_loop_hint:
+    case op_switch_imm:
+    case op_switch_char:
+    case op_switch_string:
+    case op_put_by_id:
+    case op_put_by_id_out_of_line:
+    case op_put_by_id_replace:
+    case op_put_by_id_transition:
+    case op_put_by_id_transition_direct:
+    case op_put_by_id_transition_direct_out_of_line:
+    case op_put_by_id_transition_normal:
+    case op_put_by_id_transition_normal_out_of_line:
+    case op_put_by_id_generic:
+    case op_put_getter_setter:
+    case op_put_by_val:
+    case op_put_by_val_direct:
+    case op_put_by_index:
+    case op_tear_off_arguments:
+    case op_touch_entry:
+#define LLINT_HELPER_OPCODES(opcode, length) case opcode:
+        FOR_EACH_LLINT_OPCODE_EXTENSION(LLINT_HELPER_OPCODES);
+#undef LLINT_HELPER_OPCODES
+        return;
+    // These all have a single destination for the first argument.
+    case op_next_pname:
+    case op_resolve_scope:
+    case op_strcat:
+    case op_tear_off_activation:
+    case op_to_primitive:
+    case op_catch:
+    case op_create_this:
+    case op_new_array:
+    case op_new_array_buffer:
+    case op_new_array_with_size:
+    case op_new_regexp:
+    case op_new_func:
+    case op_new_captured_func:
+    case op_new_func_exp:
+    case op_call_varargs:
+    case op_get_from_scope:
+    case op_call:
+    case op_call_eval:
+    case op_construct:
+    case op_get_by_id:
+    case op_get_by_id_out_of_line:
+    case op_get_by_id_self:
+    case op_get_by_id_proto:
+    case op_get_by_id_chain:
+    case op_get_by_id_getter_self:
+    case op_get_by_id_getter_proto:
+    case op_get_by_id_getter_chain:
+    case op_get_by_id_custom_self:
+    case op_get_by_id_custom_proto:
+    case op_get_by_id_custom_chain:
+    case op_get_by_id_generic:
+    case op_get_array_length:
+    case op_get_string_length:
+    case op_check_has_instance:
+    case op_instanceof:
+    case op_get_by_val:
+    case op_get_argument_by_val:
+    case op_get_by_pname:
+    case op_get_arguments_length:
+    case op_typeof:
+    case op_is_undefined:
+    case op_is_boolean:
+    case op_is_number:
+    case op_is_string:
+    case op_is_object:
+    case op_is_function:
+    case op_in:
+    case op_to_number:
+    case op_negate:
+    case op_add:
+    case op_mul:
+    case op_div:
+    case op_mod:
+    case op_sub:
+    case op_lshift:
+    case op_rshift:
+    case op_urshift:
+    case op_bitand:
+    case op_bitxor:
+    case op_bitor:
+    case op_inc:
+    case op_dec:
+    case op_eq:
+    case op_neq:
+    case op_stricteq:
+    case op_nstricteq:
+    case op_less:
+    case op_lesseq:
+    case op_greater:
+    case op_greatereq:
+    case op_neq_null:
+    case op_eq_null:
+    case op_not:
+    case op_mov:
+    case op_captured_mov:
+    case op_new_object:
+    case op_to_this:
+    case op_get_callee:
+    case op_init_lazy_reg:
+    case op_create_activation:
+    case op_create_arguments:
+    case op_del_by_id:
+    case op_del_by_val: {
+        functor(codeBlock, instruction, opcodeID, instruction[1].u.operand);
+        return;
+    }
+    case op_get_pnames: {
+        functor(codeBlock, instruction, opcodeID, instruction[1].u.operand);
+        functor(codeBlock, instruction, opcodeID, instruction[3].u.operand);
+        functor(codeBlock, instruction, opcodeID, instruction[4].u.operand);
+        return;
+    }
+    case op_enter: {
+        for (unsigned i = codeBlock->m_numVars; i--;)
+            functor(codeBlock, instruction, opcodeID, virtualRegisterForLocal(i).offset());
+        return;
+    } }
+}
+
+} // namespace JSC
+
+#endif // BytecodeUseDef_h
+