Update from https://crrev.com/309717

tools/valgrind/asan/third_party/asan_symbolize.py

 #!/usr/bin/env python
 #===- lib/asan/scripts/asan_symbolize.py -----------------------------------===#
 #
 #                     The LLVM Compiler Infrastructure
 #
 # This file is distributed under the University of Illinois Open Source
 # License. See LICENSE.TXT for details.
 #
 #===------------------------------------------------------------------------===#
 import argparse
@@ skipping 348 matching lines @@
     # On Darwin, if the dsym hint producer is present:
     #  1. check whether we've seen this binary already; if so,
     #     use |llvm_symbolizers[binary]|, which has already loaded the debug
     #     info for this binary (might not be the case for
     #     |last_llvm_symbolizer|);
     #  2. otherwise check if we've seen all the hints for this binary already;
     #     if so, reuse |last_llvm_symbolizer| which has the full set of hints;
     #  3. otherwise create a new symbolizer and pass all currently known
     #     .dSYM hints to it.
     if not binary in self.llvm_symbolizers:
-      use_last_symbolizer = True
+      use_new_symbolizer = True
       if self.system == 'Darwin' and self.dsym_hint_producer:
         dsym_hints_for_binary = set(self.dsym_hint_producer(binary))
-        use_last_symbolizer = bool(dsym_hints_for_binary - self.dsym_hints)
+        use_new_symbolizer = bool(dsym_hints_for_binary - self.dsym_hints)
         self.dsym_hints |= dsym_hints_for_binary
-      if self.last_llvm_symbolizer and use_last_symbolizer:
+      if self.last_llvm_symbolizer and not use_new_symbolizer:
           self.llvm_symbolizers[binary] = self.last_llvm_symbolizer
       else:
         self.last_llvm_symbolizer = LLVMSymbolizerFactory(
             self.system, guess_arch(addr), self.dsym_hints)
         self.llvm_symbolizers[binary] = self.last_llvm_symbolizer
     # Use the chain of symbolizers:
     # Breakpad symbolizer -> LLVM symbolizer -> addr2line/atos
     # (fall back to next symbolizer if the previous one fails).
     if not binary in symbolizers:
       symbolizers[binary] = ChainSymbolizer(
@@ skipping 75 matching lines @@
     binary_name_filter = sysroot_path_filter
     sysroot_path = args.s
   if args.c:
     binutils_prefix = args.c
   if args.logfile:
     logfile = args.logfile
   else:
     logfile = sys.stdin
   loop = SymbolizationLoop(binary_name_filter)
   loop.process_logfile()