libchrome: Several upstreamable fixes from libchrome

base/debug/stack_trace_posix.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/debug/stack_trace.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #include <signal.h>
 #include <stddef.h>
@@ skipping 48 matching lines @@
 // The prefix used for mangled symbols, per the Itanium C++ ABI:
 // http://www.codesourcery.com/cxx-abi/abi.html#mangling
 const char kMangledSymbolPrefix[] = "_Z";
 
 // Characters that can be used for symbols, generated by Ruby:
 // (('a'..'z').to_a+('A'..'Z').to_a+('0'..'9').to_a + ['_']).join
 const char kSymbolCharacters[] =
     "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_";
 #endif  // !defined(USE_SYMBOLIZE) && defined(__GLIBCXX__)
 
-#if !defined(USE_SYMBOLIZE)
+#if !defined(__UCLIBC__) && !defined(USE_SYMBOLIZE)

[danakj, 2016/05/23 02:59:54]

Can you explain?

[Luis Héctor Chávez, 2016/05/24 15:27:52]

DemangleSymbols is only used when neither __UCLIBC__ nor USE_SYMBOLIZE are
defined.

 // Demangles C++ symbols in the given text. Example:
 //
 // "out/Debug/base_unittests(_ZN10StackTraceC1Ev+0x20) [0x817778c]"
 // =>
 // "out/Debug/base_unittests(StackTrace::StackTrace()+0x20) [0x817778c]"
 void DemangleSymbols(std::string* text) {
   // Note: code in this function is NOT async-signal safe (std::string uses
   // malloc internally).
 
-#if defined(__GLIBCXX__) && !defined(__UCLIBC__)
+#if defined(__GLIBCXX__)
 
   std::string::size_type search_from = 0;
   while (search_from < text->size()) {
     // Look for the start of a mangled symbol, from search_from.
     std::string::size_type mangled_start =
         text->find(kMangledSymbolPrefix, search_from);
     if (mangled_start == std::string::npos) {
       break;  // Mangled symbol not found.
     }
 
@@ skipping 16 matching lines @@
       // Insert the demangled symbol.
       text->insert(mangled_start, demangled_symbol.get());
       // Next time, we'll start right after the demangled symbol we inserted.
       search_from = mangled_start + strlen(demangled_symbol.get());
     } else {
       // Failed to demangle.  Retry after the "_Z" we just found.
       search_from = mangled_start + 2;
     }
   }
 
-#endif  // defined(__GLIBCXX__) && !defined(__UCLIBC__)
+#else

[danakj, 2016/05/23 02:59:54]

comment on what this is #else-ing

[Luis Héctor Chávez, 2016/05/24 15:27:52]

Done.

+

[danakj, 2016/05/23 02:59:54]

no need for the whitespace

[Luis Héctor Chávez, 2016/05/24 15:27:52]

Done.

+  // Avoid an unused warning.
+  (void)text;
+

[danakj, 2016/05/23 02:59:54]

ditto

[Luis Héctor Chávez, 2016/05/24 15:27:52]

Done.

+#endif  // defined(__GLIBCXX__)
 }
-#endif  // !defined(USE_SYMBOLIZE)
+#endif  // !defined(__UCLIBC__) && !defined(USE_SYMBOLIZE)
 
 class BacktraceOutputHandler {
  public:
   virtual void HandleOutput(const char* output) = 0;
 
  protected:
   virtual ~BacktraceOutputHandler() {}
 };
 
 #if !defined(__UCLIBC__)
@@ skipping 675 matching lines @@
     *ptr = *start;
     *start++ = ch;
   }
   return buf;
 }
 
 }  // namespace internal
 
 }  // namespace debug
 }  // namespace base