Changeset 163685 in webkit

Timestamp:

Feb 7, 2014 6:52:05 PM (10 years ago)

Author:

mark.lam@apple.com

Message:

Unify JSLock implementation for iOS and non-iOS ports.
<​https://webkit.org/b/128409>

Reviewed by Michael Saboff.

The iOS and non-iOS implementations of dropAllLocks(),
dropAllLocksUnconditionally(), and grabAllLocks() effectively do the
same work. The main difference is that the iOS implementation acquires
the JSLock spin lock in the DropAllLocks class while the other ports
acquire it when it calls JSLock::lock() and unlock().

The other difference is that the iOS implementation will only increment
m_locksDropDepth if it actually drops locks, whereas other ports will
increment it unconditionally. Analogously, iOS decrements the depth only
when needed while other ports will decrement it unconditionally when
re-grabbing locks.

We can unify the 2 implementations by having both use the iOS
implementation for a start.

• runtime/JSLock.cpp:

(JSC::JSLock::dropAllLocks):
(JSC::JSLock::dropAllLocksUnconditionally):
(JSC::JSLock::grabAllLocks):
(JSC::JSLock::DropAllLocks::DropAllLocks):
(JSC::JSLock::DropAllLocks::~DropAllLocks):

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• runtime/JSLock.cpp (modified) (7 diffs)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2014-02-07  Mark Lam  <mark.lam@apple.com>
+
+        Unify JSLock implementation for iOS and non-iOS ports.
+        <https://webkit.org/b/128409>
+
+        Reviewed by Michael Saboff.
+
+        The iOS and non-iOS implementations of dropAllLocks(),
+        dropAllLocksUnconditionally(), and grabAllLocks() effectively do the
+        same work. The main difference is that the iOS implementation acquires
+        the JSLock spin lock in the DropAllLocks class while the other ports
+        acquire it when it calls JSLock::lock() and unlock().
+
+        The other difference is that the iOS implementation will only increment
+        m_locksDropDepth if it actually drops locks, whereas other ports will
+        increment it unconditionally. Analogously, iOS decrements the depth only
+        when needed while other ports will decrement it unconditionally when
+        re-grabbing locks.
+
+        We can unify the 2 implementations by having both use the iOS
+        implementation for a start.
+
+        * runtime/JSLock.cpp:
+        (JSC::JSLock::dropAllLocks):
+        (JSC::JSLock::dropAllLocksUnconditionally):
+        (JSC::JSLock::grabAllLocks):
+        (JSC::JSLock::DropAllLocks::DropAllLocks):
+        (JSC::JSLock::DropAllLocks::~DropAllLocks):
+
 2014-02-06  Filip Pizlo  <fpizlo@apple.com>
 

trunk/Source/JavaScriptCore/runtime/JSLock.cpp

@@ -209 +209 @@
 unsigned JSLock::dropAllLocks(SpinLock& spinLock)
 {
-#if PLATFORM(IOS)
     ASSERT_UNUSED(spinLock, spinLock.IsHeld());
     // Check if this thread is currently holding the lock.
@@ -232 +231 @@
     m_lock.unlock();
     return lockCount;
-#else
-    if (m_lockDropDepth++)
-        return 0;
-
-    return dropAllLocksUnconditionally(spinLock);
-#endif
 }
 
 unsigned JSLock::dropAllLocksUnconditionally(SpinLock& spinLock)
 {
-#if PLATFORM(IOS)
     ASSERT_UNUSED(spinLock, spinLock.IsHeld());
     // Check if this thread is currently holding the lock.
@@ -259 +251 @@
     m_lock.unlock();
     return lockCount;
-#else
-    UNUSED_PARAM(spinLock);
-    unsigned lockCount = m_lockCount;
-    for (unsigned i = 0; i < lockCount; ++i)
-        unlock();
-
-    return lockCount;
-#endif
 }
 
 void JSLock::grabAllLocks(unsigned lockCount, SpinLock& spinLock)
 {
-#if PLATFORM(IOS)
     ASSERT(spinLock.IsHeld());
     // If no locks were dropped, nothing to do!
@@ -294 +277 @@
     m_lockCount = lockCount;
     --m_lockDropDepth;
-#else
-    UNUSED_PARAM(spinLock);
-    for (unsigned i = 0; i < lockCount; ++i)
-        lock();
-
-    --m_lockDropDepth;
-#endif
 }
 
@@ -310 +286 @@
         return;
     SpinLock& spinLock = m_vm->apiLock().m_spinLock;
-#if PLATFORM(IOS)
     SpinLockHolder holder(&spinLock);
-#endif
 
     WTFThreadData& threadData = wtfThreadData();
@@ -333 +307 @@
         return;
     SpinLock& spinLock = m_vm->apiLock().m_spinLock;
-#if PLATFORM(IOS)
     SpinLockHolder holder(&spinLock);
-#endif
 
     WTFThreadData& threadData = wtfThreadData();
@@ -354 +326 @@
         return;
     SpinLock& spinLock = m_vm->apiLock().m_spinLock;
-#if PLATFORM(IOS)
     SpinLockHolder holder(&spinLock);
-#endif
     m_vm->apiLock().grabAllLocks(m_lockCount, spinLock);