[CVE-2018-8510] Edge - missing BytecodeUses for IsIn optimization leads to type confusion

lib/Backend/GlobOptArrays.cpp

@@ -320,7 +320,8 @@ void GlobOpt::ArraySrcOpt::CheckVirtualArrayBounds()
                 {
                     Assert(instr->m_opcode == Js::OpCode::InlineArrayPush ||
                         instr->m_opcode == Js::OpCode::InlineArrayPop ||
-                        instr->m_opcode == Js::OpCode::LdLen_A);
+                        instr->m_opcode == Js::OpCode::LdLen_A ||
+                        instr->m_opcode == Js::OpCode::IsIn);
                 }
 
                 eliminatedLowerBoundCheck = true;
@@ -1988,6 +1989,8 @@ void GlobOpt::ArraySrcOpt::Optimize()
         {
             TRACE_TESTTRACE_PHASE_INSTR(Js::Phase::BoundCheckEliminationPhase, instr, _u("Eliminating IsIn\n"));
 
+            globOpt->CaptureByteCodeSymUses(instr);
+
             instr->m_opcode = Js::OpCode::Ld_A;
 
             IR::AddrOpnd * addrOpnd = IR::AddrOpnd::New(func->GetScriptContextInfo()->GetTrueAddr(), IR::AddrOpndKindDynamicVar, func, true);