config/gcc-stl-wrapper.template.h
author Mike Hommey <mh+mozilla@glandium.org>
Wed, 18 May 2016 16:37:19 +0900
changeset 337400 68da139d0866977c0ada86319fa94388f2255446
parent 337399 a640e6fa8ab9977fb6c5bcf63dc4daca6699477b
child 447133 0c9996186048d2ad338c153861fb1c8aa80ce181
permissions -rw-r--r--
Bug 1269171 - Change how mozalloc.h is hooked in STL wrappers. r=froydnj Since the introduction of the STL wrappers, they have included mozalloc.h, and multiple times, we've hit header reentrancy problems, and worked around them as best as we could. Taking a step back, all mozalloc.h does is: - declare moz_* allocator functions. - define inline implementations of various operator new/delete variants. The first only requires the functions to be declared before they are used, so mozalloc.h only needs to be included before anything that would use those functions. The second doesn't actually require a specific order, as long as the declaration for those functions comes before their use, and they are either declared in <new> or implicitly by the C++ compiler. So all in all, it doesn't matter that mozalloc.h is included before the wrapped STL headers. What matters is that it's included when STL headers are included. So arrange things such that mozalloc.h is included after the first wrapped STL header is fully preprocessed (and all its includes have been included).

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: sw=2 ts=8 et :
 */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef mozilla_${HEADER}_h
#define mozilla_${HEADER}_h

// For some reason, Apple's GCC refuses to honor -fno-exceptions when
// compiling ObjC.
#if defined(__EXCEPTIONS) && __EXCEPTIONS && !(__OBJC__ && __GNUC__ && XP_IOS)
#  error "STL code can only be used with -fno-exceptions"
#endif

// Silence "warning: #include_next is a GCC extension"
#pragma GCC system_header

#if defined(DEBUG) && !defined(_GLIBCXX_DEBUG)
// Enable checked iterators and other goodies
//
// FIXME/bug 551254: gcc's debug STL implementation requires -frtti.
// Figure out how to resolve this with -fno-rtti.  Maybe build with
// -frtti in DEBUG builds?
//
//  # define _GLIBCXX_DEBUG 1
#endif

// Don't include mozalloc for cstdlib. See bug 1245076.
#ifndef moz_dont_include_mozalloc_for_cstdlib
#  define moz_dont_include_mozalloc_for_cstdlib
#endif

// Include mozalloc after the STL header and all other headers it includes
// have been preprocessed.
#if !defined(MOZ_INCLUDE_MOZALLOC_H) && \
    !defined(moz_dont_include_mozalloc_for_${HEADER})
#  define MOZ_INCLUDE_MOZALLOC_H
#  define MOZ_INCLUDE_MOZALLOC_H_FROM_${HEADER}
#endif

#pragma GCC visibility push(default)
#include_next <${HEADER}>
#pragma GCC visibility pop

#ifdef MOZ_INCLUDE_MOZALLOC_H_FROM_${HEADER}
// See if we're in code that can use mozalloc.  NB: this duplicates
// code in nscore.h because nscore.h pulls in prtypes.h, and chromium
// can't build with that being included before base/basictypes.h.
#  if !defined(XPCOM_GLUE) && !defined(NS_NO_XPCOM) && !defined(MOZ_NO_MOZALLOC)
#    include "mozilla/mozalloc.h"
#  else
#    error "STL code can only be used with infallible ::operator new()"
#  endif
#endif

// gcc calls a __throw_*() function from bits/functexcept.h when it
// wants to "throw an exception".  functexcept exists nominally to
// support -fno-exceptions, but since we'll always use the system
// libstdc++, and it's compiled with exceptions, then in practice
// these __throw_*() functions will always throw exceptions (shades of
// -fshort-wchar).  We don't want that and so define our own inlined
// __throw_*().
#ifndef mozilla_throw_gcc_h
#  include "mozilla/throw_gcc.h"
#endif

#endif  // if mozilla_${HEADER}_h