Fix the atomicIncrement implementation for MIPS GCC

https://bugs.webkit.org/show_bug.cgi?id=106739

Patch by Balazs Kilvady <kilvadyb@homejinni.com> on 2013-02-26
Reviewed by Oliver Hunt.

Implementation of missing __sync_[add|sub]_and_fetch_8 functions.

Some architectures, like MIPS32, don't have GCC implementation for
builtin __sync_* functions with 64 bits variable size. GCC answer
for the problem: If a target doesn't support atomic operations on
certain variable sizes, you are out of luck with atomicity in that
case (http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56296). GCC >= 4.8
will support __atomic_* builtin functions for this purpose for all
the GCC targets, but for current compilers we have to include our
own implementation.

* GNUmakefile.list.am:
* WTF.pro:
* wtf/Atomics.cpp: Added.
(WTF):
(WTF::getSwapLock):
(WTF::atomicStep):
* wtf/CMakeLists.txt:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@144077 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Conflicts:
	Source/WTF/ChangeLog

Change-Id: I98ce0ccd6747253ae6fa36fe9d338e155945a043
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@digia.com>
Reviewed-by: Jocelyn Turcotte <jocelyn.turcotte@digia.com>

5 files changed, 140 insertions, 0 deletions

diff --git a/Source/WTF/ChangeLog b/Source/WTF/ChangeLog
index 0f8b6debe..fe3005dc0 100644
--- a/Source/WTF/ChangeLog
+++ b/Source/WTF/ChangeLog
@@ -1,3 +1,29 @@
+2013-02-26  Balazs Kilvady  <kilvadyb@homejinni.com>
+
+        Fix the atomicIncrement implementation for MIPS GCC
+        https://bugs.webkit.org/show_bug.cgi?id=106739
+
+        Reviewed by Oliver Hunt.
+
+        Implementation of missing __sync_[add|sub]_and_fetch_8 functions.
+
+        Some architectures, like MIPS32, don't have GCC implementation for
+        builtin __sync_* functions with 64 bits variable size. GCC answer
+        for the problem: If a target doesn't support atomic operations on
+        certain variable sizes, you are out of luck with atomicity in that
+        case (http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56296). GCC >= 4.8
+        will support __atomic_* builtin functions for this purpose for all
+        the GCC targets, but for current compilers we have to include our
+        own implementation.
+
+        * GNUmakefile.list.am:
+        * WTF.pro:
+        * wtf/Atomics.cpp: Added.
+        (WTF):
+        (WTF::getSwapLock):
+        (WTF::atomicStep):
+        * wtf/CMakeLists.txt:
+
 2013-02-18  Balazs Kilvady  <kilvadyb@homejinni.com>
 
         MIPS DFG implementation.
diff --git a/Source/WTF/GNUmakefile.list.am b/Source/WTF/GNUmakefile.list.am
index 88cce1398..0955a0587 100644
--- a/Source/WTF/GNUmakefile.list.am
+++ b/Source/WTF/GNUmakefile.list.am
@@ -11,6 +11,7 @@ wtf_sources += \
     Source/WTF/wtf/ArrayBufferView.h \
     Source/WTF/wtf/Assertions.cpp \
     Source/WTF/wtf/Assertions.h \
+    Source/WTF/wtf/Atomics.cpp \
     Source/WTF/wtf/Atomics.h \
     Source/WTF/wtf/BitArray.h \
     Source/WTF/wtf/BitVector.cpp \
diff --git a/Source/WTF/WTF.pro b/Source/WTF/WTF.pro
index 366194bbd..8725afb08 100644
--- a/Source/WTF/WTF.pro
+++ b/Source/WTF/WTF.pro
@@ -196,6 +196,7 @@ SOURCES += \
     ArrayBuffer.cpp \
     ArrayBufferView.cpp \
     Assertions.cpp \
+    Atomics.cpp \
     BitVector.cpp \
     CryptographicallyRandomNumber.cpp \
     CurrentTime.cpp \
diff --git a/Source/WTF/wtf/Atomics.cpp b/Source/WTF/wtf/Atomics.cpp
new file mode 100644
index 000000000..bcaedf740
--- /dev/null
+++ b/Source/WTF/wtf/Atomics.cpp
@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2007, 2008, 2010, 2012 Apple Inc. All rights reserved.
+ * Copyright (C) 2007 Justin Haygood (jhaygood@reaktix.com)
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1.  Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ * 2.  Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
+ *     its contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ *
+ * Note: The implementations of InterlockedIncrement and InterlockedDecrement are based
+ * on atomic_increment and atomic_exchange_and_add from the Boost C++ Library. The license
+ * is virtually identical to the Apple license above but is included here for completeness.
+ *
+ * Boost Software License - Version 1.0 - August 17th, 2003
+ *
+ * Permission is hereby granted, free of charge, to any person or organization
+ * obtaining a copy of the software and accompanying documentation covered by
+ * this license (the "Software") to use, reproduce, display, distribute,
+ * execute, and transmit the Software, and to prepare derivative works of the
+ * Software, and to permit third-parties to whom the Software is furnished to
+ * do so, all subject to the following:
+ *
+ * The copyright notices in the Software and this entire statement, including
+ * the above license grant, this restriction and the following disclaimer,
+ * must be included in all copies of the Software, in whole or in part, and
+ * all derivative works of the Software, unless such copies or derivative
+ * works are solely in the form of machine-executable object code generated by
+ * a source language processor.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
+ * SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
+ * FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include "config.h"
+
+// Some architectures, like MIPS32, don't have GCC implementation for builtin __sync_* functions
+// with 64 bits variable size. Official GCC answer for the problem: If a target doesn't support
+// atomic operations on certain variable sizes, you are out of luck with atomicity in that case
+// (http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56296). GCC >= 4.8 will support __atomic_* builtin
+// functions for this purpose for all the GCC targets, but for current compilers we have to include
+// our own implementation.
+#if COMPILER(GCC) && !defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8) && USE(LOCKFREE_THREADSAFEREFCOUNTED) && USE(PTHREADS)
+
+#include "Atomics.h"
+
+#include "ThreadingPrimitives.h"
+
+namespace WTF {
+
+static const size_t kSwapLockCount = 32;
+static Mutex s_swapLocks[kSwapLockCount];
+
+static inline Mutex& getSwapLock(const volatile int64_t* addr)
+{
+    return s_swapLocks[(reinterpret_cast<intptr_t>(addr) >> 3U) % kSwapLockCount];
+}
+
+static int64_t atomicStep(int64_t volatile* addend, int64_t step)
+{
+    Mutex& mutex = getSwapLock(addend);
+
+    mutex.lock();
+    int64_t value = *addend + step;
+    *addend = value;
+    mutex.unlock();
+
+    return value;
+}
+
+extern "C" {
+
+int64_t __sync_add_and_fetch_8(int64_t volatile* addend, int64_t value)
+{
+    return atomicStep(addend, value);
+}
+
+int64_t __sync_sub_and_fetch_8(int64_t volatile* addend, int64_t value)
+{
+    return atomicStep(addend, -value);
+}
+
+} // extern "C"
+
+} // namespace WTF
+
+#endif
diff --git a/Source/WTF/wtf/CMakeLists.txt b/Source/WTF/wtf/CMakeLists.txt
index 9ba49504b..b7f437c64 100644
--- a/Source/WTF/wtf/CMakeLists.txt
+++ b/Source/WTF/wtf/CMakeLists.txt
@@ -157,6 +157,7 @@ SET(WTF_SOURCES
     ArrayBuffer.cpp
     ArrayBufferView.cpp
     Assertions.cpp
+    Atomics.cpp
     BitVector.cpp
     CryptographicallyRandomNumber.cpp
     CurrentTime.cpp