<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;">On Jun 3, 2014, at 2:28 PM, Nico Weber <<a href="mailto:thakis@chromium.org">thakis@chromium.org</a>> wrote:<br><div><br class="Apple-interchange-newline"><blockquote type="cite"><div dir="ltr">Ping?</div></blockquote><div><br></div><div>Is there some reason that you’re using __SIZEOF_SIZE_T__ instead of sizeof(size_t) ?</div></div><div><br></div><div>Other than that, LGTM.</div><div><br></div><div>— Marshall</div><div><br><blockquote type="cite"><div class="gmail_extra"><br><br><div class="gmail_quote">On Mon, Jun 2, 2014 at 10:11 AM, Nico Weber <span dir="ltr"><<a href="mailto:thakis@chromium.org" target="_blank">thakis@chromium.org</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Ping.</div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br><br><div class="gmail_quote">
On Fri, May 30, 2014 at 4:04 PM, Nico Weber <span dir="ltr"><<a href="mailto:thakis@chromium.org" target="_blank">thakis@chromium.org</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Hi,<div><br></div><div>on trunk, libc++ relies on undefined initialization order of global initializers when using gcc:</div>
<div><br></div><div>1. __start_std_streams in iostream.cpp calls locale::id::_init, which assigns an id to each locale::facet in an initializer</div>
<div><br></div><div>2. Every facet has a static locale::id id, whose constructor sets the facet's id to 0*</div><div><br></div><div>If 2 runs after 1, it clobbers the facet's assigned consecutive id, causing exceptions to be thrown when e.g. running code like "cout << endl".</div>
<div><br></div><div>To fix this, the attached patch lets _LIBCPP_CONSTEXPR evaluate to "constexpr" instead of nothing with gcc. locale::id's constructor is marked _LIBCPP_CONSTEXPR, which ensures that it won't get an initializer that could potentially run after the iostream.cpp initializer. (This remains broken when building with msvc.)</div>
<div><br></div><div>Once _LIBCPP_CONSTEXPR is available, bitset fails to compile since gcc doesn't define __SIZE_WIDTH__, so switch bitset to use __SIZEOF_SIZE_T__ which both clang and gcc define.</div><div><br></div>
<div>Pair-programmed/debugged with Dana Jansens.</div><span><font color="#888888"><div><br></div><div>Nico</div>
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