Use address-taken to disambiguate global variable and indirect memops.

Major steps include:
 1). introduces a not-addr-taken bit-field in GlobalVariable
 2). GlobalOpt pass sets "not-address-taken" if it proves a global varirable 
    dosen't have its address taken.
 3). AA use this info for disambiguation. 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193251 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Bitcode/Reader/BitcodeReader.cpp

@@ -1848,6 +1848,9 @@ bool BitcodeReader::ParseModule(bool Resume) {
         new GlobalVariable(*TheModule, Ty, isConstant, Linkage, 0, "", 0,
                            TLM, AddressSpace, ExternallyInitialized);
       NewGV->setAlignment(Alignment);
+      if (Record.size() > 10)
+        NewGV->setAddressMaybeTaken(Record[10]);
+
       if (!Section.empty())
         NewGV->setSection(Section);
       NewGV->setVisibility(Visibility);