<html dir="ltr">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<style id="owaParaStyle" type="text/css">P {margin-top:0;margin-bottom:0;}</style>
</head>
<body ocsi="0" fpstyle="1">
<div style="direction: ltr;font-family: Courier New;color: #000000;font-size: 10pt;">
I changed the type of message from fatal_error to warning in r260961. While the test for atomics works fine in most cases, it fails because we include <cstdint> and <atomic>, and the user's host compiler might not provide them during a bootstrap (see PR26631
and PR26622).<br>
<br>
Does anyone have any idea how to tackle this problem? As suggested by the bug reports, we could include the headers provided by libc++. However, I'm not sure whether we are supposed to do that during configuration time.<br>
<br>
- Vasileios<br>
<br>
<br>
<a href="http://llvm.org/viewvc/llvm-project/?view=rev&revision=260961"></a>
<div style="font-family: Times New Roman; color: #000000; font-size: 16px">
<hr tabindex="-1">
<div style="direction: ltr;" id="divRpF790598"><font color="#000000" size="2" face="Tahoma"><b>From:</b> Eric Fiselier [eric@efcs.ca]<br>
<b>Sent:</b> 11 February 2016 16:08<br>
<b>To:</b> Daniel Sanders<br>
<b>Cc:</b> Vasileios Kalintiris; hans@chromium.org; mclow.lists@gmail.com; cfe-commits@lists.llvm.org<br>
<b>Subject:</b> Re: [libcxx] r260235 - Introduce a cmake module to figure out whether we need to link with libatomic.<br>
</font><br>
</div>
<div></div>
<div>
<div dir="ltr">
<div>> <span style="font-size:12.8px"> we need to rename HAVE_CXX_ATOMICS_WITH_LIB to something like LIBCXX_HAVE_CXX_ATOMICS_WITH_</span><span style="font-size:12.8px">LIB.<br>
</span><br>
</div>
<div>Fixed in r260531.</div>
<div><br>
</div>
<div>I think we will eventually want to merge the following commits, assuming they don't regress the build, especially with the -gcc-toolchain option.</div>
<div><br>
</div>
<div>- <span style="font-size:inherit; font-weight:inherit">[libcxx] r260515 - Re-commit "Introduce a cmake module to figure out whether we need to link with libatomic."</span></div>
<div>- <span style="font-size:inherit; font-weight:inherit">[libcxx] r260524 - Fix r260515 - Correct typos in CMake changes</span></div>
<div><span style="font-size:inherit; font-weight:inherit">- </span><span style="font-size:inherit; font-weight:inherit">[libcxx] r260531 - Rename CheckLibcxxAtomic.cm</span><span style="font-size:inherit; font-weight:inherit">ake variable result names so they
don't clash with LLVM</span></div>
<div><span style="font-size:inherit; font-weight:inherit"><br>
</span></div>
<div><span style="font-size:inherit; font-weight:inherit">@Marshall Any objections?</span></div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Thu, Feb 11, 2016 at 2:18 AM, Daniel Sanders via cfe-commits
<span dir="ltr"><<a href="mailto:cfe-commits@lists.llvm.org" target="_blank">cfe-commits@lists.llvm.org</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex; border-left:1px #ccc solid; padding-left:1ex">
Hi,<br>
<br>
In my latests rc2+patches build I've also found that we need to rename HAVE_CXX_ATOMICS_WITH_LIB to something like LIBCXX_HAVE_CXX_ATOMICS_WITH_LIB. It's currently re-using the result of LLVM's check which doesn't include 64-bit atomics.<br>
________________________________________<br>
From: Vasileios Kalintiris<br>
Sent: 09 February 2016 23:50<br>
<div class="HOEnZb">
<div class="h5">To: <a href="mailto:hans@chromium.org" target="_blank">hans@chromium.org</a><br>
Cc: <a href="mailto:cfe-commits@lists.llvm.org" target="_blank">cfe-commits@lists.llvm.org</a>; Daniel Sanders;
<a href="mailto:mclow.lists@gmail.com" target="_blank">mclow.lists@gmail.com</a><br>
Subject: RE: [libcxx] r260235 - Introduce a cmake module to figure out whether we need to link with libatomic.<br>
<br>
Hi Hans,<br>
<br>
Please wait before merging this as it breaks LLVM bootstraps when using the -gcc-toolchain option and the system's default gcc installation does not provide libatomic. We have to check LIBCXX_GCC_TOOLCHAIN in our test. I'll create a patch tomorrow and I'll
let you know when it's okay to merge them. In the meantime, I reverted it in r260323.<br>
<br>
- Vasileios<br>
________________________________________<br>
From: Vasileios Kalintiris<br>
Sent: 09 February 2016 18:56<br>
To: <a href="mailto:hans@chromium.org" target="_blank">hans@chromium.org</a><br>
Cc: <a href="mailto:cfe-commits@lists.llvm.org" target="_blank">cfe-commits@lists.llvm.org</a>; Daniel Sanders;
<a href="mailto:mclow.lists@gmail.com" target="_blank">mclow.lists@gmail.com</a><br>
Subject: RE: [libcxx] r260235 - Introduce a cmake module to figure out whether we need to link with libatomic.<br>
<br>
Hi Hans,<br>
<br>
Can we merge this on the 3.8 release branch? It fixes libcxx builds on MIPS by linking with libatomic when needed. Also, all the x86_64 and ARM buildbots for libcxx look good.<br>
<br>
Thanks,<br>
Vasileios<br>
<br>
________________________________________<br>
From: cfe-commits [<a href="mailto:cfe-commits-bounces@lists.llvm.org" target="_blank">cfe-commits-bounces@lists.llvm.org</a>] on behalf of Vasileios Kalintiris via cfe-commits [<a href="mailto:cfe-commits@lists.llvm.org" target="_blank">cfe-commits@lists.llvm.org</a>]<br>
Sent: 09 February 2016 17:00<br>
To: <a href="mailto:cfe-commits@lists.llvm.org" target="_blank">cfe-commits@lists.llvm.org</a><br>
Subject: [libcxx] r260235 - Introduce a cmake module to figure out whether we need to link with libatomic.<br>
<br>
Author: vkalintiris<br>
Date: Tue Feb 9 11:00:38 2016<br>
New Revision: 260235<br>
<br>
URL: <a href="http://llvm.org/viewvc/llvm-project?rev=260235&view=rev" rel="noreferrer" target="_blank">
http://llvm.org/viewvc/llvm-project?rev=260235&view=rev</a><br>
Log:<br>
Introduce a cmake module to figure out whether we need to link with libatomic.<br>
<br>
Summary:<br>
This fixes the tests under std/atomics for 32-bit MIPS CPUs where the<br>
8-byte atomic operations call into the libatomic library.<br>
<br>
Reviewers: dsanders, mclow.lists, EricWF, jroelofs, joerg<br>
<br>
Subscribers: cfe-commits<br>
<br>
Differential Revision: <a href="http://reviews.llvm.org/D16613" rel="noreferrer" target="_blank">
http://reviews.llvm.org/D16613</a><br>
<br>
Added:<br>
libcxx/trunk/cmake/Modules/CheckLibcxxAtomic.cmake<br>
Modified:<br>
libcxx/trunk/cmake/config-ix.cmake<br>
libcxx/trunk/lib/CMakeLists.txt<br>
libcxx/trunk/test/CMakeLists.txt<br>
libcxx/trunk/test/libcxx/test/target_info.py<br>
libcxx/trunk/test/<a href="http://lit.site.cfg.in" rel="noreferrer" target="_blank">lit.site.cfg.in</a><br>
<br>
Added: libcxx/trunk/cmake/Modules/CheckLibcxxAtomic.cmake<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/libcxx/trunk/cmake/Modules/CheckLibcxxAtomic.cmake?rev=260235&view=auto" rel="noreferrer" target="_blank">
http://llvm.org/viewvc/llvm-project/libcxx/trunk/cmake/Modules/CheckLibcxxAtomic.cmake?rev=260235&view=auto</a><br>
==============================================================================<br>
--- libcxx/trunk/cmake/Modules/CheckLibcxxAtomic.cmake (added)<br>
+++ libcxx/trunk/cmake/Modules/CheckLibcxxAtomic.cmake Tue Feb 9 11:00:38 2016<br>
@@ -0,0 +1,38 @@<br>
+INCLUDE(CheckCXXSourceCompiles)<br>
+<br>
+# Sometimes linking against libatomic is required for atomic ops, if<br>
+# the platform doesn't support lock-free atomics.<br>
+#<br>
+# We could modify LLVM's CheckAtomic module and have it check for 64-bit<br>
+# atomics instead. However, we would like to avoid careless uses of 64-bit<br>
+# atomics inside LLVM over time on 32-bit platforms.<br>
+<br>
+function(check_cxx_atomics varname)<br>
+ set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})<br>
+ set(CMAKE_REQUIRED_FLAGS "-std=c++11")<br>
+ check_cxx_source_compiles("<br>
+#include <cstdint><br>
+#include <atomic><br>
+std::atomic<uintptr_t> x;<br>
+std::atomic<uintmax_t> y;<br>
+int main() {<br>
+ return x + y;<br>
+}<br>
+" ${varname})<br>
+ set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})<br>
+endfunction(check_cxx_atomics)<br>
+<br>
+check_cxx_atomics(HAVE_CXX_ATOMICS_WITHOUT_LIB)<br>
+# If not, check if the library exists, and atomics work with it.<br>
+if(NOT HAVE_CXX_ATOMICS_WITHOUT_LIB)<br>
+ check_library_exists(atomic __atomic_fetch_add_8 "" HAVE_LIBATOMIC)<br>
+ if(HAVE_LIBATOMIC)<br>
+ list(APPEND CMAKE_REQUIRED_LIBRARIES "atomic")<br>
+ check_cxx_atomics(HAVE_CXX_ATOMICS_WITH_LIB)<br>
+ if (NOT HAVE_CXX_ATOMICS_WITH_LIB)<br>
+ message(FATAL_ERROR "Host compiler must support std::atomic!")<br>
+ endif()<br>
+ else()<br>
+ message(FATAL_ERROR "Host compiler appears to require libatomic, but cannot find it.")<br>
+ endif()<br>
+endif()<br>
<br>
Modified: libcxx/trunk/cmake/config-ix.cmake<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/libcxx/trunk/cmake/config-ix.cmake?rev=260235&r1=260234&r2=260235&view=diff" rel="noreferrer" target="_blank">
http://llvm.org/viewvc/llvm-project/libcxx/trunk/cmake/config-ix.cmake?rev=260235&r1=260234&r2=260235&view=diff</a><br>
==============================================================================<br>
--- libcxx/trunk/cmake/config-ix.cmake (original)<br>
+++ libcxx/trunk/cmake/config-ix.cmake Tue Feb 9 11:00:38 2016<br>
@@ -1,5 +1,6 @@<br>
include(CheckLibraryExists)<br>
include(CheckCXXCompilerFlag)<br>
+include(CheckLibcxxAtomic)<br>
<br>
# Check compiler flags<br>
<br>
@@ -17,3 +18,7 @@ check_library_exists(c fopen "" LIBCXX_H<br>
check_library_exists(m ccos "" LIBCXX_HAS_M_LIB)<br>
check_library_exists(rt clock_gettime "" LIBCXX_HAS_RT_LIB)<br>
check_library_exists(gcc_s __gcc_personality_v0 "" LIBCXX_HAS_GCC_S_LIB)<br>
+<br>
+if (NOT HAVE_CXX_ATOMICS_WITHOUT_LIB)<br>
+ set(LIBCXX_HAS_ATOMIC_LIB True)<br>
+endif()<br>
<br>
Modified: libcxx/trunk/lib/CMakeLists.txt<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/libcxx/trunk/lib/CMakeLists.txt?rev=260235&r1=260234&r2=260235&view=diff" rel="noreferrer" target="_blank">
http://llvm.org/viewvc/llvm-project/libcxx/trunk/lib/CMakeLists.txt?rev=260235&r1=260234&r2=260235&view=diff</a><br>
==============================================================================<br>
--- libcxx/trunk/lib/CMakeLists.txt (original)<br>
+++ libcxx/trunk/lib/CMakeLists.txt Tue Feb 9 11:00:38 2016<br>
@@ -79,6 +79,7 @@ add_library_flags_if(LIBCXX_HAS_C_LIB c)<br>
add_library_flags_if(LIBCXX_HAS_M_LIB m)<br>
add_library_flags_if(LIBCXX_HAS_RT_LIB rt)<br>
add_library_flags_if(LIBCXX_HAS_GCC_S_LIB gcc_s)<br>
+add_library_flags_if(LIBCXX_HAS_ATOMIC_LIB atomic)<br>
<br>
# Setup flags.<br>
add_flags_if_supported(-fPIC)<br>
<br>
Modified: libcxx/trunk/test/CMakeLists.txt<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/CMakeLists.txt?rev=260235&r1=260234&r2=260235&view=diff" rel="noreferrer" target="_blank">
http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/CMakeLists.txt?rev=260235&r1=260234&r2=260235&view=diff</a><br>
==============================================================================<br>
--- libcxx/trunk/test/CMakeLists.txt (original)<br>
+++ libcxx/trunk/test/CMakeLists.txt Tue Feb 9 11:00:38 2016<br>
@@ -15,6 +15,7 @@ pythonize_bool(LIBCXX_ENABLE_SHARED)<br>
pythonize_bool(LIBCXX_BUILD_32_BITS)<br>
pythonize_bool(LIBCXX_GENERATE_COVERAGE)<br>
pythonize_bool(LIBCXXABI_USE_LLVM_UNWINDER)<br>
+pythonize_bool(LIBCXX_HAS_ATOMIC_LIB)<br>
<br>
# The tests shouldn't link to any ABI library when it has been linked into<br>
# libc++ statically or via a linker script.<br>
<br>
Modified: libcxx/trunk/test/libcxx/test/target_info.py<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/libcxx/test/target_info.py?rev=260235&r1=260234&r2=260235&view=diff" rel="noreferrer" target="_blank">
http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/libcxx/test/target_info.py?rev=260235&r1=260234&r2=260235&view=diff</a><br>
==============================================================================<br>
--- libcxx/trunk/test/libcxx/test/target_info.py (original)<br>
+++ libcxx/trunk/test/libcxx/test/target_info.py Tue Feb 9 11:00:38 2016<br>
@@ -172,6 +172,9 @@ class LinuxLocalTI(DefaultTargetInfo):<br>
flags += ['-lunwind', '-ldl']<br>
else:<br>
flags += ['-lgcc_s', '-lgcc']<br>
+ use_libatomic = self.full_config.get_lit_bool('use_libatomic', False)<br>
+ if use_libatomic:<br>
+ flags += ['-latomic']<br>
san = self.full_config.get_lit_conf('use_sanitizer', '').strip()<br>
if san:<br>
# The libraries and their order are taken from the<br>
<br>
Modified: libcxx/trunk/test/<a href="http://lit.site.cfg.in" rel="noreferrer" target="_blank">lit.site.cfg.in</a><br>
URL: <a href="http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/lit.site.cfg.in?rev=260235&r1=260234&r2=260235&view=diff" rel="noreferrer" target="_blank">
http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/lit.site.cfg.in?rev=260235&r1=260234&r2=260235&view=diff</a><br>
==============================================================================<br>
--- libcxx/trunk/test/<a href="http://lit.site.cfg.in" rel="noreferrer" target="_blank">lit.site.cfg.in</a> (original)<br>
+++ libcxx/trunk/test/<a href="http://lit.site.cfg.in" rel="noreferrer" target="_blank">lit.site.cfg.in</a> Tue Feb 9 11:00:38 2016<br>
@@ -20,6 +20,7 @@ config.generate_coverage = "@LIBC<br>
config.target_info = "@LIBCXX_TARGET_INFO@"<br>
config.executor = "@LIBCXX_EXECUTOR@"<br>
config.llvm_unwinder = "@LIBCXXABI_USE_LLVM_UNWINDER@"<br>
+config.use_libatomic = "@LIBCXX_HAS_ATOMIC_LIB@"<br>
<br>
# Let the main config do the real work.<br>
lit_config.load_config(config, "@LIBCXX_SOURCE_DIR@/test/lit.cfg")<br>
<br>
<br>
_______________________________________________<br>
cfe-commits mailing list<br>
<a href="mailto:cfe-commits@lists.llvm.org" target="_blank">cfe-commits@lists.llvm.org</a><br>
<a href="http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits" rel="noreferrer" target="_blank">http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits</a><br>
_______________________________________________<br>
cfe-commits mailing list<br>
<a href="mailto:cfe-commits@lists.llvm.org" target="_blank">cfe-commits@lists.llvm.org</a><br>
<a href="http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits" rel="noreferrer" target="_blank">http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits</a><br>
</div>
</div>
</blockquote>
</div>
<br>
</div>
</div>
</div>
</div>
</body>
</html>