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<dt>Revision</dt> <dd><a href="http://trac.webkit.org/projects/webkit/changeset/184218">184218</a></dd>
<dt>Author</dt> <dd>mark.lam@apple.com</dd>
<dt>Date</dt> <dd>2015-05-12 14:20:26 -0700 (Tue, 12 May 2015)</dd>
</dl>
<h3>Log Message</h3>
<pre>Refactor MachineStackMarker.cpp so that it's easier to reason about MachineThreads::Thread.
https://bugs.webkit.org/show_bug.cgi?id=144925
Reviewed by Michael Saboff.
Currently, the code in MachineStackMarker.cpp is written as a bunch of functions that
operate on the platformThread value in the MachineThreads::Thread struct. Instead, we
can apply better OO encapsulation and convert all these functions into methods of the
MachineThreads::Thread struct.
This will also make it easier to reason about the fix for
https://bugs.webkit.org/show_bug.cgi?id=144924 later.
* heap/MachineStackMarker.cpp:
(JSC::getCurrentPlatformThread):
(JSC::MachineThreads::Thread::createForCurrentThread):
(JSC::MachineThreads::Thread::operator!=):
(JSC::MachineThreads::Thread::operator==):
(JSC::MachineThreads::addCurrentThread):
(JSC::MachineThreads::removeThreadIfFound):
(JSC::MachineThreads::Thread::suspend):
(JSC::MachineThreads::Thread::resume):
(JSC::MachineThreads::Thread::getRegisters):
(JSC::MachineThreads::Thread::Registers::stackPointer):
(JSC::MachineThreads::Thread::freeRegisters):
(JSC::MachineThreads::Thread::captureStack):
(JSC::MachineThreads::tryCopyOtherThreadStack):
(JSC::MachineThreads::tryCopyOtherThreadStacks):
(JSC::equalThread): Deleted.
(JSC::suspendThread): Deleted.
(JSC::resumeThread): Deleted.
(JSC::getPlatformThreadRegisters): Deleted.
(JSC::otherThreadStackPointer): Deleted.
(JSC::freePlatformThreadRegisters): Deleted.
(JSC::otherThreadStack): Deleted.</pre>
<h3>Modified Paths</h3>
<ul>
<li><a href="#trunkSourceJavaScriptCoreChangeLog">trunk/Source/JavaScriptCore/ChangeLog</a></li>
<li><a href="#trunkSourceJavaScriptCoreheapMachineStackMarkercpp">trunk/Source/JavaScriptCore/heap/MachineStackMarker.cpp</a></li>
</ul>
</div>
<div id="patch">
<h3>Diff</h3>
<a id="trunkSourceJavaScriptCoreChangeLog"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/ChangeLog (184217 => 184218)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/ChangeLog 2015-05-12 21:04:10 UTC (rev 184217)
+++ trunk/Source/JavaScriptCore/ChangeLog 2015-05-12 21:20:26 UTC (rev 184218)
</span><span class="lines">@@ -1,3 +1,41 @@
</span><ins>+2015-05-12 Mark Lam <mark.lam@apple.com>
+
+ Refactor MachineStackMarker.cpp so that it's easier to reason about MachineThreads::Thread.
+ https://bugs.webkit.org/show_bug.cgi?id=144925
+
+ Reviewed by Michael Saboff.
+
+ Currently, the code in MachineStackMarker.cpp is written as a bunch of functions that
+ operate on the platformThread value in the MachineThreads::Thread struct. Instead, we
+ can apply better OO encapsulation and convert all these functions into methods of the
+ MachineThreads::Thread struct.
+
+ This will also make it easier to reason about the fix for
+ https://bugs.webkit.org/show_bug.cgi?id=144924 later.
+
+ * heap/MachineStackMarker.cpp:
+ (JSC::getCurrentPlatformThread):
+ (JSC::MachineThreads::Thread::createForCurrentThread):
+ (JSC::MachineThreads::Thread::operator!=):
+ (JSC::MachineThreads::Thread::operator==):
+ (JSC::MachineThreads::addCurrentThread):
+ (JSC::MachineThreads::removeThreadIfFound):
+ (JSC::MachineThreads::Thread::suspend):
+ (JSC::MachineThreads::Thread::resume):
+ (JSC::MachineThreads::Thread::getRegisters):
+ (JSC::MachineThreads::Thread::Registers::stackPointer):
+ (JSC::MachineThreads::Thread::freeRegisters):
+ (JSC::MachineThreads::Thread::captureStack):
+ (JSC::MachineThreads::tryCopyOtherThreadStack):
+ (JSC::MachineThreads::tryCopyOtherThreadStacks):
+ (JSC::equalThread): Deleted.
+ (JSC::suspendThread): Deleted.
+ (JSC::resumeThread): Deleted.
+ (JSC::getPlatformThreadRegisters): Deleted.
+ (JSC::otherThreadStackPointer): Deleted.
+ (JSC::freePlatformThreadRegisters): Deleted.
+ (JSC::otherThreadStack): Deleted.
+
</ins><span class="cx"> 2015-05-12 Ryosuke Niwa <rniwa@webkit.org>
</span><span class="cx">
</span><span class="cx"> Array.slice should have a fast path like Array.splice
</span></span></pre></div>
<a id="trunkSourceJavaScriptCoreheapMachineStackMarkercpp"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/heap/MachineStackMarker.cpp (184217 => 184218)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/heap/MachineStackMarker.cpp 2015-05-12 21:04:10 UTC (rev 184217)
+++ trunk/Source/JavaScriptCore/heap/MachineStackMarker.cpp 2015-05-12 21:20:26 UTC (rev 184218)
</span><span class="lines">@@ -146,10 +146,20 @@
</span><span class="cx"> return *manager;
</span><span class="cx"> }
</span><span class="cx">
</span><ins>+static inline PlatformThread getCurrentPlatformThread()
+{
+#if OS(DARWIN)
+ return pthread_mach_thread_np(pthread_self());
+#elif OS(WINDOWS)
+ return GetCurrentThread();
+#elif USE(PTHREADS)
+ return pthread_self();
+#endif
+}
</ins><span class="cx">
</span><span class="cx"> class MachineThreads::Thread {
</span><span class="cx"> WTF_MAKE_FAST_ALLOCATED;
</span><del>-public:
</del><ins>+
</ins><span class="cx"> Thread(const PlatformThread& platThread, void* base)
</span><span class="cx"> : platformThread(platThread)
</span><span class="cx"> , stackBase(base)
</span><span class="lines">@@ -169,6 +179,52 @@
</span><span class="cx"> #endif
</span><span class="cx"> }
</span><span class="cx">
</span><ins>+public:
+ static Thread* createForCurrentThread()
+ {
+ return new Thread(getCurrentPlatformThread(), wtfThreadData().stack().origin());
+ }
+
+ struct Registers {
+ inline void* stackPointer() const;
+
+#if OS(DARWIN)
+#if CPU(X86)
+ typedef i386_thread_state_t PlatformRegisters;
+#elif CPU(X86_64)
+ typedef x86_thread_state64_t PlatformRegisters;
+#elif CPU(PPC)
+ typedef ppc_thread_state_t PlatformRegisters;
+#elif CPU(PPC64)
+ typedef ppc_thread_state64_t PlatformRegisters;
+#elif CPU(ARM)
+ typedef arm_thread_state_t PlatformRegisters;
+#elif CPU(ARM64)
+ typedef arm_thread_state64_t PlatformRegisters;
+#else
+#error Unknown Architecture
+#endif
+
+#elif OS(WINDOWS)
+ typedef CONTEXT PlatformRegisters;
+#elif USE(PTHREADS)
+ typedef pthread_attr_t PlatformRegisters;
+#else
+#error Need a thread register struct for this platform
+#endif
+
+ PlatformRegisters regs;
+ };
+
+ inline bool operator==(const PlatformThread& other) const;
+ inline bool operator!=(const PlatformThread& other) const { return !(*this == other); }
+
+ inline bool suspend();
+ inline void resume();
+ size_t getRegisters(Registers&);
+ void freeRegisters(Registers&);
+ std::pair<void*, size_t> captureStack(void* stackTop);
+
</ins><span class="cx"> Thread* next;
</span><span class="cx"> PlatformThread platformThread;
</span><span class="cx"> void* stackBase;
</span><span class="lines">@@ -199,23 +255,12 @@
</span><span class="cx"> }
</span><span class="cx"> }
</span><span class="cx">
</span><del>-static inline PlatformThread getCurrentPlatformThread()
</del><ins>+inline bool MachineThreads::Thread::operator==(const PlatformThread& other) const
</ins><span class="cx"> {
</span><del>-#if OS(DARWIN)
- return pthread_mach_thread_np(pthread_self());
-#elif OS(WINDOWS)
- return GetCurrentThread();
-#elif USE(PTHREADS)
- return pthread_self();
-#endif
-}
-
-static inline bool equalThread(const PlatformThread& first, const PlatformThread& second)
-{
</del><span class="cx"> #if OS(DARWIN) || OS(WINDOWS)
</span><del>- return first == second;
</del><ins>+ return platformThread == other;
</ins><span class="cx"> #elif USE(PTHREADS)
</span><del>- return !!pthread_equal(first, second);
</del><ins>+ return !!pthread_equal(platformThread, other);
</ins><span class="cx"> #else
</span><span class="cx"> #error Need a way to compare threads on this platform
</span><span class="cx"> #endif
</span><span class="lines">@@ -231,7 +276,7 @@
</span><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> threadSpecificSet(m_threadSpecific, this);
</span><del>- Thread* thread = new Thread(getCurrentPlatformThread(), wtfThreadData().stack().origin());
</del><ins>+ Thread* thread = Thread::createForCurrentThread();
</ins><span class="cx">
</span><span class="cx"> MutexLocker lock(m_registeredThreadsMutex);
</span><span class="cx">
</span><span class="lines">@@ -258,15 +303,14 @@
</span><span class="cx"> void MachineThreads::removeThreadIfFound(PlatformThread platformThread)
</span><span class="cx"> {
</span><span class="cx"> MutexLocker lock(m_registeredThreadsMutex);
</span><del>- if (equalThread(platformThread, m_registeredThreads->platformThread)) {
- Thread* t = m_registeredThreads;
</del><ins>+ Thread* t = m_registeredThreads;
+ if (*t == platformThread) {
</ins><span class="cx"> m_registeredThreads = m_registeredThreads->next;
</span><span class="cx"> delete t;
</span><span class="cx"> } else {
</span><span class="cx"> Thread* last = m_registeredThreads;
</span><del>- Thread* t;
</del><span class="cx"> for (t = m_registeredThreads->next; t; t = t->next) {
</span><del>- if (equalThread(t->platformThread, platformThread)) {
</del><ins>+ if (*t == platformThread) {
</ins><span class="cx"> last->next = t->next;
</span><span class="cx"> break;
</span><span class="cx"> }
</span><span class="lines">@@ -285,7 +329,7 @@
</span><span class="cx"> conservativeRoots.add(stackTop, stackOrigin, jitStubRoutines, codeBlocks);
</span><span class="cx"> }
</span><span class="cx">
</span><del>-static inline bool suspendThread(const PlatformThread& platformThread)
</del><ins>+inline bool MachineThreads::Thread::suspend()
</ins><span class="cx"> {
</span><span class="cx"> #if OS(DARWIN)
</span><span class="cx"> kern_return_t result = thread_suspend(platformThread);
</span><span class="lines">@@ -302,7 +346,7 @@
</span><span class="cx"> #endif
</span><span class="cx"> }
</span><span class="cx">
</span><del>-static inline void resumeThread(const PlatformThread& platformThread)
</del><ins>+inline void MachineThreads::Thread::resume()
</ins><span class="cx"> {
</span><span class="cx"> #if OS(DARWIN)
</span><span class="cx"> thread_resume(platformThread);
</span><span class="lines">@@ -315,38 +359,10 @@
</span><span class="cx"> #endif
</span><span class="cx"> }
</span><span class="cx">
</span><del>-typedef unsigned long usword_t; // word size, assumed to be either 32 or 64 bit
-
-#if OS(DARWIN)
-
-#if CPU(X86)
-typedef i386_thread_state_t PlatformThreadRegisters;
-#elif CPU(X86_64)
-typedef x86_thread_state64_t PlatformThreadRegisters;
-#elif CPU(PPC)
-typedef ppc_thread_state_t PlatformThreadRegisters;
-#elif CPU(PPC64)
-typedef ppc_thread_state64_t PlatformThreadRegisters;
-#elif CPU(ARM)
-typedef arm_thread_state_t PlatformThreadRegisters;
-#elif CPU(ARM64)
-typedef arm_thread_state64_t PlatformThreadRegisters;
-#else
-#error Unknown Architecture
-#endif
-
-#elif OS(WINDOWS)
-typedef CONTEXT PlatformThreadRegisters;
-#elif USE(PTHREADS)
-typedef pthread_attr_t PlatformThreadRegisters;
-#else
-#error Need a thread register struct for this platform
-#endif
-
-static size_t getPlatformThreadRegisters(const PlatformThread& platformThread, PlatformThreadRegisters& regs)
</del><ins>+size_t MachineThreads::Thread::getRegisters(MachineThreads::Thread::Registers& registers)
</ins><span class="cx"> {
</span><ins>+ Thread::Registers::PlatformRegisters& regs = registers.regs;
</ins><span class="cx"> #if OS(DARWIN)
</span><del>-
</del><span class="cx"> #if CPU(X86)
</span><span class="cx"> unsigned user_count = sizeof(regs)/sizeof(int);
</span><span class="cx"> thread_state_flavor_t flavor = i386_THREAD_STATE;
</span><span class="lines">@@ -375,7 +391,7 @@
</span><span class="cx"> "JavaScript garbage collection failed because thread_get_state returned an error (%d). This is probably the result of running inside Rosetta, which is not supported.", result);
</span><span class="cx"> CRASH();
</span><span class="cx"> }
</span><del>- return user_count * sizeof(usword_t);
</del><ins>+ return user_count * sizeof(uintptr_t);
</ins><span class="cx"> // end OS(DARWIN)
</span><span class="cx">
</span><span class="cx"> #elif OS(WINDOWS)
</span><span class="lines">@@ -399,7 +415,7 @@
</span><span class="cx"> #endif
</span><span class="cx"> }
</span><span class="cx">
</span><del>-static inline void* otherThreadStackPointer(const PlatformThreadRegisters& regs)
</del><ins>+inline void* MachineThreads::Thread::Registers::stackPointer() const
</ins><span class="cx"> {
</span><span class="cx"> #if OS(DARWIN)
</span><span class="cx">
</span><span class="lines">@@ -467,8 +483,9 @@
</span><span class="cx"> #endif
</span><span class="cx"> }
</span><span class="cx">
</span><del>-static void freePlatformThreadRegisters(PlatformThreadRegisters& regs)
</del><ins>+void MachineThreads::Thread::freeRegisters(MachineThreads::Thread::Registers& registers)
</ins><span class="cx"> {
</span><ins>+ Thread::Registers::PlatformRegisters& regs = registers.regs;
</ins><span class="cx"> #if USE(PTHREADS) && !OS(WINDOWS) && !OS(DARWIN)
</span><span class="cx"> pthread_attr_destroy(&regs);
</span><span class="cx"> #else
</span><span class="lines">@@ -476,13 +493,11 @@
</span><span class="cx"> #endif
</span><span class="cx"> }
</span><span class="cx">
</span><del>-static std::pair<void*, size_t> otherThreadStack(void* stackBase, const PlatformThreadRegisters& registers)
</del><ins>+std::pair<void*, size_t> MachineThreads::Thread::captureStack(void* stackTop)
</ins><span class="cx"> {
</span><span class="cx"> void* begin = stackBase;
</span><span class="cx"> void* end = reinterpret_cast<void*>(
</span><del>- WTF::roundUpToMultipleOf<sizeof(void*)>(
- reinterpret_cast<uintptr_t>(
- otherThreadStackPointer(registers))));
</del><ins>+ WTF::roundUpToMultipleOf<sizeof(void*)>(reinterpret_cast<uintptr_t>(stackTop)));
</ins><span class="cx"> if (begin > end)
</span><span class="cx"> std::swap(begin, end);
</span><span class="cx"> return std::make_pair(begin, static_cast<char*>(end) - static_cast<char*>(begin));
</span><span class="lines">@@ -513,9 +528,9 @@
</span><span class="cx"> // will deadlock if 'thread' holds that lock.
</span><span class="cx"> void MachineThreads::tryCopyOtherThreadStack(Thread* thread, void* buffer, size_t capacity, size_t* size)
</span><span class="cx"> {
</span><del>- PlatformThreadRegisters registers;
- size_t registersSize = getPlatformThreadRegisters(thread->platformThread, registers);
- std::pair<void*, size_t> stack = otherThreadStack(thread->stackBase, registers);
</del><ins>+ Thread::Registers registers;
+ size_t registersSize = thread->getRegisters(registers);
+ std::pair<void*, size_t> stack = thread->captureStack(registers.stackPointer());
</ins><span class="cx">
</span><span class="cx"> bool canCopy = *size + registersSize + stack.second <= capacity;
</span><span class="cx">
</span><span class="lines">@@ -527,7 +542,7 @@
</span><span class="cx"> memcpy(static_cast<char*>(buffer) + *size, stack.first, stack.second);
</span><span class="cx"> *size += stack.second;
</span><span class="cx">
</span><del>- freePlatformThreadRegisters(registers);
</del><ins>+ thread->freeRegisters(registers);
</ins><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> bool MachineThreads::tryCopyOtherThreadStacks(MutexLocker&, void* buffer, size_t capacity, size_t* size)
</span><span class="lines">@@ -541,8 +556,8 @@
</span><span class="cx">
</span><span class="cx"> Thread* previousThread = nullptr;
</span><span class="cx"> for (Thread* thread = m_registeredThreads; thread; index++) {
</span><del>- if (!equalThread(thread->platformThread, currentPlatformThread)) {
- bool success = suspendThread(thread->platformThread);
</del><ins>+ if (*thread != currentPlatformThread) {
+ bool success = thread->suspend();
</ins><span class="cx"> #if OS(DARWIN)
</span><span class="cx"> if (!success) {
</span><span class="cx"> if (!numberOfThreads) {
</span><span class="lines">@@ -585,13 +600,13 @@
</span><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> for (Thread* thread = m_registeredThreads; thread; thread = thread->next) {
</span><del>- if (!equalThread(thread->platformThread, currentPlatformThread))
</del><ins>+ if (*thread != currentPlatformThread)
</ins><span class="cx"> tryCopyOtherThreadStack(thread, buffer, capacity, size);
</span><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> for (Thread* thread = m_registeredThreads; thread; thread = thread->next) {
</span><del>- if (!equalThread(thread->platformThread, currentPlatformThread))
- resumeThread(thread->platformThread);
</del><ins>+ if (*thread != currentPlatformThread)
+ thread->resume();
</ins><span class="cx"> }
</span><span class="cx">
</span><span class="cx"> for (Thread* thread = threadsToBeDeleted; thread; ) {
</span></span></pre>
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