<html>
<head>
<base href="https://bugs.llvm.org/">
</head>
<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - lib/clang/13.0.0/include/intrin.h is missing __readfsdword"
href="https://bugs.llvm.org/show_bug.cgi?id=51188">51188</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>lib/clang/13.0.0/include/intrin.h is missing __readfsdword
</td>
</tr>
<tr>
<th>Product</th>
<td>libc++
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Windows NT
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>All Bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>brucedawson@chromium.org
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org, mclow.lists@gmail.com
</td>
</tr></table>
<p>
<div>
<pre>While trying to get V8 to compile without requiring windows.h for most
translation units I hit a problem on one build configuration where
__readfsdword is unavailable, despite including intrin.h. This happens when
intrin.h is included from
third_party/llvm-build/Release+Asserts/lib/clang/13.0.0/include/intrin.h.
I cannot reproduce this in a Chromium build but in a V8 stand-alone build it
can be reproduced with these gn args:
is_component_build = true
is_debug = true
symbol_level = 1
target_cpu = "x86"
use_goma = true
v8_enable_backtrace = true
v8_enable_google_benchmark = true
v8_enable_slow_dchecks = true
Many targets fail to build. One example is obj/v8_libbase/strings.obj.
The relevant section of intrin.h seems to be this block which has function
definitions for reading 1, 8, and 2 bytes, but not 4:
unsigned char __readfsbyte(unsigned long);
unsigned __int64 __readfsqword(unsigned long);
unsigned short __readfsword(unsigned long);
See the try jobs in <a href="https://chromium-review.googlesource.com/c/v8/v8/+/3042215">https://chromium-review.googlesource.com/c/v8/v8/+/3042215</a>
for an example of the failures, on the v8_win_compile_dbg bot.
<a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - clang-cl's intrin.h does not include several intrinsics for aarch64"
href="show_bug.cgi?id=38726">https://bugs.llvm.org/show_bug.cgi?id=38726</a> looks similar, but different.</pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are on the CC list for the bug.</li>
</ul>
</body>
</html>