Modified: releases/WebKitGTK/webkit-2.14/Source/WTF/ChangeLog (207072 => 207073)
--- releases/WebKitGTK/webkit-2.14/Source/WTF/ChangeLog 2016-10-11 09:25:14 UTC (rev 207072)
+++ releases/WebKitGTK/webkit-2.14/Source/WTF/ChangeLog 2016-10-11 09:53:39 UTC (rev 207073)
@@ -1,3 +1,45 @@
+2016-09-14 JF Bastien <jfbast...@apple.com>
+
+ Alwasys inline atomic operations
+ https://bugs.webkit.org/show_bug.cgi?id=155371
+
+ Reviewed by Geoffrey Garen.
+
+ Fixes "build fails with memory model cannot be stronger than
+ success memory model for ‘__atomic_compare_exchange’".
+
+ Pre-5 revisions of GCC at Os only generated an error message
+ related to invalid failure memory ordering. The reason is that
+ libstdc++ tries to be clever about enforcing the C++ standard's
+ clause [atomics.types.operations.req] ¶21 which states:
+
+ Requires: The failure argument shall not be
+ `memory_order_release` nor `memory_order_acq_rel`. The failure
+ argument shall be no stronger than the success argument.
+
+ It fails at doing this because its inlining heuristics are
+ modified by Os, and they're not quite as dumb as O0 but not smart
+ enough to get to the good code at O1. Adding ALWAYS_INLINE fixes
+ the silliness at Os, leaves O1 great, and makes O0 slightly less
+ bad but still pretty bad.
+
+ The other good news is that I'm going to get this particular
+ problem fixed in the version of C++ which will come after C++17:
+
+ https://github.com/jfbastien/papers/blob/master/source/P0418r1.bs
+
+ While we're at it we should always inline all of these wrapped
+ functions because the generated code is horrendous if the memory
+ order isn't known at compile time.
+
+ * wtf/Atomics.h:
+ (WTF::Atomic::load):
+ (WTF::Atomic::store):
+ (WTF::Atomic::compareExchangeWeak):
+ (WTF::Atomic::compareExchangeStrong):
+ (WTF::Atomic::exchangeAndAdd):
+ (WTF::Atomic::exchange):
+
2016-09-12 Filip Pizlo <fpi...@apple.com>
ParkingLot is going to have a bad time with threads dying
Modified: releases/WebKitGTK/webkit-2.14/Source/WTF/wtf/Atomics.h (207072 => 207073)
--- releases/WebKitGTK/webkit-2.14/Source/WTF/wtf/Atomics.h 2016-10-11 09:25:14 UTC (rev 207072)
+++ releases/WebKitGTK/webkit-2.14/Source/WTF/wtf/Atomics.h 2016-10-11 09:53:39 UTC (rev 207073)
@@ -52,11 +52,11 @@
// what you are doing and have thought about it very hard. The cost of seq_cst
// is usually not high enough to justify the risk.
- T load(std::memory_order order = std::memory_order_seq_cst) const { return value.load(order); }
+ ALWAYS_INLINE T load(std::memory_order order = std::memory_order_seq_cst) const { return value.load(order); }
- void store(T desired, std::memory_order order = std::memory_order_seq_cst) { value.store(desired, order); }
+ ALWAYS_INLINE void store(T desired, std::memory_order order = std::memory_order_seq_cst) { value.store(desired, order); }
- bool compareExchangeWeak(T expected, T desired, std::memory_order order = std::memory_order_seq_cst)
+ ALWAYS_INLINE bool compareExchangeWeak(T expected, T desired, std::memory_order order = std::memory_order_seq_cst)
{
#if OS(WINDOWS)
// Windows makes strange assertions about the argument to compare_exchange_weak, and anyway,
@@ -67,7 +67,7 @@
return value.compare_exchange_weak(expectedOrActual, desired, order);
}
- bool compareExchangeStrong(T expected, T desired, std::memory_order order = std::memory_order_seq_cst)
+ ALWAYS_INLINE bool compareExchangeStrong(T expected, T desired, std::memory_order order = std::memory_order_seq_cst)
{
#if OS(WINDOWS)
// See above.
@@ -78,7 +78,7 @@
}
template<typename U>
- T exchangeAndAdd(U addend, std::memory_order order = std::memory_order_seq_cst)
+ ALWAYS_INLINE T exchangeAndAdd(U addend, std::memory_order order = std::memory_order_seq_cst)
{
#if OS(WINDOWS)
// See above.
@@ -87,7 +87,7 @@
return value.fetch_add(addend, order);
}
- T exchange(T newValue, std::memory_order order = std::memory_order_seq_cst)
+ ALWAYS_INLINE T exchange(T newValue, std::memory_order order = std::memory_order_seq_cst)
{
#if OS(WINDOWS)
// See above.
