Diff
Modified: branches/safari-602-branch/Source/_javascript_Core/ChangeLog (204016 => 204017)
--- branches/safari-602-branch/Source/_javascript_Core/ChangeLog 2016-08-02 06:51:26 UTC (rev 204016)
+++ branches/safari-602-branch/Source/_javascript_Core/ChangeLog 2016-08-02 06:51:31 UTC (rev 204017)
@@ -1,5 +1,52 @@
2016-08-01 Babak Shafiei <[email protected]>
+ Merge r204010. rdar://problem/27534844
+
+ 2016-08-01 Filip Pizlo <[email protected]>
+
+ REGRESSION (r203990): JSC Debug test stress/arity-check-ftl-throw.js failing
+ https://bugs.webkit.org/show_bug.cgi?id=160438
+
+ Reviewed by Mark Lam.
+
+ In r203990 I fixed a bug where CommonSlowPaths.h/arityCheckFor() was basically failing at
+ catching stack overflow due to large parameter count. It would only catch regular old stack
+ overflow, like if the frame pointer was already past the limit.
+
+ This had a secondary problem: unfortunately all of our tests for what happens when you overflow
+ the stack due to large parameter count were not going down that path at all, so we haven't had
+ test coverage for this in ages. There were bugs in all tiers of the engine when handling this
+ case.
+
+ We need to be able to roll back the topCallFrame on paths that are meant to throw an exception
+ from the caller. Otherwise, we'd crash in StackVisitor because it would see a busted stack
+ frame. Rolling back like this "just works" except when the caller is the VM entry frame. I had
+ some choices here. I could have forced anyone who is rolling back to always skip VM entry
+ frames. They can't do it in a way that changes the value of VM::topVMEntryFrame, which is what
+ a stack frame roll back normally does, since exception unwinding needs to see the current value
+ of topVMEntryFrame. So, we have a choice to either try to magically avoid all of the paths that
+ look at topCallFrame, or give topCallFrame a state that unambiguously signals that we are
+ sitting right on top of a VM entry frame without having succeeded at making a JS call. The only
+ place that really needs to know is StackVisitor, which wants to start scanning at topCallFrame.
+ To signal this, I could have either made topCallFrame point to the real top JS call frame
+ without also rolling back topVMEntryFrame, or I could make topCallFrame == topVMEntryFrame. The
+ latter felt somehow cleaner. I filed a bug (https://bugs.webkit.org/show_bug.cgi?id=160441) for
+ converting topCallFrame to a void*, which would give us a chance to harden the rest of the
+ engine against this case.
+
+ * interpreter/StackVisitor.cpp:
+ (JSC::StackVisitor::StackVisitor):
+ We may do ShadowChicken processing, which invokes StackVisitor, when we have topCallFrame
+ pointing at topVMEntryFrame. This teaches StackVisitor how to handle this case. I believe that
+ StackVisitor is the only place that needs to be taught about this at this time, because it's
+ one of the few things that access topCallFrame along this special path.
+
+ * jit/JITOperations.cpp: Roll back the top call frame.
+ * runtime/CommonSlowPaths.cpp:
+ (JSC::SLOW_PATH_DECL): Roll back the top call frame.
+
+2016-08-01 Babak Shafiei <[email protected]>
+
Merge r203990. rdar://problem/27534844
2016-08-01 Filip Pizlo <[email protected]>
Modified: branches/safari-602-branch/Source/_javascript_Core/interpreter/StackVisitor.cpp (204016 => 204017)
--- branches/safari-602-branch/Source/_javascript_Core/interpreter/StackVisitor.cpp 2016-08-02 06:51:26 UTC (rev 204016)
+++ branches/safari-602-branch/Source/_javascript_Core/interpreter/StackVisitor.cpp 2016-08-02 06:51:31 UTC (rev 204017)
@@ -43,6 +43,11 @@
if (startFrame) {
m_frame.m_VMEntryFrame = startFrame->vm().topVMEntryFrame;
topFrame = startFrame->vm().topCallFrame;
+
+ if (topFrame && static_cast<void*>(m_frame.m_VMEntryFrame) == static_cast<void*>(topFrame)) {
+ topFrame = vmEntryRecord(m_frame.m_VMEntryFrame)->m_prevTopCallFrame;
+ m_frame.m_VMEntryFrame = vmEntryRecord(m_frame.m_VMEntryFrame)->m_prevTopVMEntryFrame;
+ }
} else {
m_frame.m_VMEntryFrame = 0;
topFrame = 0;
Modified: branches/safari-602-branch/Source/_javascript_Core/jit/JITOperations.cpp (204016 => 204017)
--- branches/safari-602-branch/Source/_javascript_Core/jit/JITOperations.cpp 2016-08-02 06:51:26 UTC (rev 204016)
+++ branches/safari-602-branch/Source/_javascript_Core/jit/JITOperations.cpp 2016-08-02 06:51:31 UTC (rev 204017)
@@ -2172,7 +2172,7 @@
void JIT_OPERATION lookupExceptionHandlerFromCallerFrame(VM* vm, ExecState* exec)
{
- NativeCallFrameTracer tracer(vm, exec);
+ vm->topCallFrame = exec->callerFrame();
genericUnwind(vm, exec, UnwindFromCallerFrame);
ASSERT(vm->targetMachinePCForThrow);
}
Modified: branches/safari-602-branch/Source/_javascript_Core/runtime/CommonSlowPaths.cpp (204016 => 204017)
--- branches/safari-602-branch/Source/_javascript_Core/runtime/CommonSlowPaths.cpp 2016-08-02 06:51:26 UTC (rev 204016)
+++ branches/safari-602-branch/Source/_javascript_Core/runtime/CommonSlowPaths.cpp 2016-08-02 06:51:31 UTC (rev 204017)
@@ -181,7 +181,8 @@
int slotsToAdd = CommonSlowPaths::arityCheckFor(exec, vm, CodeForCall);
if (slotsToAdd < 0) {
exec = exec->callerFrame();
- ErrorHandlingScope errorScope(exec->vm());
+ vm.topCallFrame = exec;
+ ErrorHandlingScope errorScope(vm);
CommonSlowPaths::interpreterThrowInCaller(exec, createStackOverflowError(exec));
RETURN_TWO(bitwise_cast<void*>(static_cast<uintptr_t>(1)), exec);
}
@@ -194,7 +195,8 @@
int slotsToAdd = CommonSlowPaths::arityCheckFor(exec, vm, CodeForConstruct);
if (slotsToAdd < 0) {
exec = exec->callerFrame();
- ErrorHandlingScope errorScope(exec->vm());
+ vm.topCallFrame = exec;
+ ErrorHandlingScope errorScope(vm);
CommonSlowPaths::interpreterThrowInCaller(exec, createStackOverflowError(exec));
RETURN_TWO(bitwise_cast<void*>(static_cast<uintptr_t>(1)), exec);
}
Modified: branches/safari-602-branch/Source/_javascript_Core/runtime/VM.h (204016 => 204017)
--- branches/safari-602-branch/Source/_javascript_Core/runtime/VM.h 2016-08-02 06:51:26 UTC (rev 204016)
+++ branches/safari-602-branch/Source/_javascript_Core/runtime/VM.h 2016-08-02 06:51:31 UTC (rev 204017)
@@ -278,7 +278,11 @@
VMType vmType;
ClientData* clientData;
VMEntryFrame* topVMEntryFrame;
- ExecState* topCallFrame;
+ // NOTE: When throwing an exception while rolling back the call frame, this may be equal to
+ // topVMEntryFrame.
+ // FIXME: This should be a void*, because it might not point to a CallFrame.
+ // https://bugs.webkit.org/show_bug.cgi?id=160441
+ ExecState* topCallFrame;
Strong<Structure> structureStructure;
Strong<Structure> structureRareDataStructure;
Strong<Structure> terminatedExecutionErrorStructure;
