Title: [290871] trunk/Source/_javascript_Core
- Revision
- 290871
- Author
- [email protected]
- Date
- 2022-03-05 13:55:27 -0800 (Sat, 05 Mar 2022)
Log Message
Optimize VMTraps::maybeNeedHandling().
https://bugs.webkit.org/show_bug.cgi?id=237503
Reviewed by Saam Barati.
There's no need for VMTraps::maybeNeedHandling() to mask the VMTraps bits for
events. Under normal circumstances, there are no traps firing and the traps bits
are 0 anyway. We should optimize for this and do away with the masking. Clients
who use VMTraps::maybeNeedHandling() should and current do call VMTraps::needHandling()
to get the real story on whether there are actually traps to handle or not. Hence,
the masking in VMTraps::maybeNeedHandling() is also not needed for correctness.
We know from experience that changes in RETURN_IN_EXCEPTION can have an impact on
performance. Perhaps this change can also help performance.
* runtime/ExceptionScope.h:
* runtime/VMTraps.h:
(JSC::VMTraps::maybeNeedHandling const):
Modified Paths
Diff
Modified: trunk/Source/_javascript_Core/ChangeLog (290870 => 290871)
--- trunk/Source/_javascript_Core/ChangeLog 2022-03-05 21:24:10 UTC (rev 290870)
+++ trunk/Source/_javascript_Core/ChangeLog 2022-03-05 21:55:27 UTC (rev 290871)
@@ -1,5 +1,26 @@
2022-03-05 Mark Lam <[email protected]>
+ Optimize VMTraps::maybeNeedHandling().
+ https://bugs.webkit.org/show_bug.cgi?id=237503
+
+ Reviewed by Saam Barati.
+
+ There's no need for VMTraps::maybeNeedHandling() to mask the VMTraps bits for
+ events. Under normal circumstances, there are no traps firing and the traps bits
+ are 0 anyway. We should optimize for this and do away with the masking. Clients
+ who use VMTraps::maybeNeedHandling() should and current do call VMTraps::needHandling()
+ to get the real story on whether there are actually traps to handle or not. Hence,
+ the masking in VMTraps::maybeNeedHandling() is also not needed for correctness.
+
+ We know from experience that changes in RETURN_IN_EXCEPTION can have an impact on
+ performance. Perhaps this change can also help performance.
+
+ * runtime/ExceptionScope.h:
+ * runtime/VMTraps.h:
+ (JSC::VMTraps::maybeNeedHandling const):
+
+2022-03-05 Mark Lam <[email protected]>
+
Fix broken SuspendExceptionScope and remove redundant VM::DeferExceptionScope.
https://bugs.webkit.org/show_bug.cgi?id=237441
<rdar://problem/89769627>
Modified: trunk/Source/_javascript_Core/runtime/ExceptionScope.h (290870 => 290871)
--- trunk/Source/_javascript_Core/runtime/ExceptionScope.h 2022-03-05 21:24:10 UTC (rev 290870)
+++ trunk/Source/_javascript_Core/runtime/ExceptionScope.h 2022-03-05 21:55:27 UTC (rev 290871)
@@ -1,5 +1,5 @@
/*
- * Copyright (C) 2016-2021 Apple Inc. All rights reserved.
+ * Copyright (C) 2016-2022 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@@ -110,7 +110,7 @@
#define RETURN_IF_EXCEPTION(scope__, value__) do { \
JSC::VM& vm = (scope__).vm(); \
ASSERT(!!(scope__).exception() == vm.traps().needHandling(JSC::VMTraps::NeedExceptionHandling)); \
- if (UNLIKELY(vm.traps().maybeNeedHandling(JSC::VMTraps::NonDebuggerEvents))) { \
+ if (UNLIKELY(vm.traps().maybeNeedHandling())) { \
if (vm.hasExceptionsAfterHandlingTraps()) \
return value__; \
} \
Modified: trunk/Source/_javascript_Core/runtime/VMTraps.h (290870 => 290871)
--- trunk/Source/_javascript_Core/runtime/VMTraps.h 2022-03-05 21:24:10 UTC (rev 290870)
+++ trunk/Source/_javascript_Core/runtime/VMTraps.h 2022-03-05 21:55:27 UTC (rev 290871)
@@ -1,5 +1,5 @@
/*
- * Copyright (C) 2017-2021 Apple Inc. All rights reserved.
+ * Copyright (C) 2017-2022 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@@ -203,7 +203,7 @@
return false;
}
// Designed to be a fast check to rule out if we might need handling, and we need to ensure needHandling on the slow path.
- ALWAYS_INLINE bool maybeNeedHandling(BitField mask) const { return m_trapBits.loadRelaxed() & mask; }
+ ALWAYS_INLINE bool maybeNeedHandling() const { return m_trapBits.loadRelaxed(); }
void* trapBitsAddress() { return &m_trapBits; }
enum class DeferAction {
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