Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

[JSC] Skip ProxyObject's ICs trap result validation in the common case #13349

Merged
merged 1 commit into from
May 2, 2023

Conversation

shvaikalesh
Copy link
Member

@shvaikalesh shvaikalesh commented May 2, 2023

052608b

[JSC] Skip ProxyObject's ICs trap result validation in the common case
https://bugs.webkit.org/show_bug.cgi?id=255661
<rdar://problem/108269769>

Reviewed by Yusuke Suzuki.

Invariants of the essential internal methods [1] are enforced for all objects, both ordinary and exotic,
to avoid them having unpredictable behavior that negatively impacts developer experience and creates
security issues.

Enforcing them for Proxy objects is especially cumbersome, given traps are userland code, and quite
expensive performance-wise: invariants invalidation requires checking property attributes,
which currently requires JS => C++ call.

After carefully analyzing all the invariants of the all internal methods, it was concluded that if
[[ProxyTarget]] is an ordinary extensible object without non-configurable properties, validation of
the invariants can be safely (non-observably) skipped.

trap name                   IC    attributes checked
========================    ==    ==================================
getOwnPropertyDescriptor    no    non-configurable || non-extensible
defineProperty              no    non-configurable || non-extensible
has                        yes    non-configurable || non-extensible
get                        yes    non-configurable && (non-writable || accessor)
set                        yes    non-configurable && (non-writable || accessor)
deleteProperty           maybe    non-configurable || non-extensible
ownKeys                     no    non-configurable || non-extensible

This change:

  1. Introduces OverridesIsExtensible out-of-line type info flag to tighten Structure's didPreventExtensions
     flag, making it more pessimistic: it being `true` doesn't necessarily mean the structure is non-extensible,
     but the reverse (it being `false`) can be safely relied on.

     It's not a completely new approach: #11843 does the same thing.

     This change was proven not to introduce bugs since Structure's didPreventExtensions flag is currently
     relied upon only for objects without isExtensible() override.

  2. Introduces hasNonConfigurableProperties and hasNonConfigurableReadOnlyOrGetterSetterProperties Structure
     flags that are also pessimistic.

     When inferring their initial values, we do extra care not to be overly pessimistic for objects except
     JSFinalObject by checking overridesGetOwnPropertySlot() so that userland code, which heavily uses
     Map / Set as [[ProxyTarget]], is also performant, while making an exception for JSArray's non-configurable
     non-structure "length" property.

     While there is existing hasReadOnlyOrGetterSetterPropertiesExcludingProto flag, we can't combine it with
     hasNonConfigurableProperties because MobX installs a non-writable administration property even on arrays,
     which have non-configurable "length" already, so combining them would disable optimization for JSArray.

  3. Introduces HasStructureWithFlags bytecode op to be utilized in ProxyObject IC helpers to skip trap result
     validation for most of ProxyObject's targets. In the follow-ups, this approach will be expanded to C++ code.

Currently, due to lack of proper profiling of GetInternalField results, constant folding for HasStructureWithFlags
doesn't happen in microbenchmarks.

                                   ToT                      patch

proxy-has-miss              159.9825+-2.4190     ^     43.1435+-0.5994        ^ definitely 3.7082x faster
proxy-set-miss-handler      158.7617+-2.3615     ^    139.2158+-1.9197        ^ definitely 1.1404x faster
proxy-set                   125.5967+-1.3678     ^     14.4533+-0.1739        ^ definitely 8.6898x faster
proxy-get                   115.8061+-2.2413     ^     14.2136+-0.1138        ^ definitely 8.1475x faster

<geometric>                 138.5985+-0.9526     ^     33.3237+-0.2255        ^ definitely 4.1592x faster

[1]: https://tc39.es/ecma262/#sec-invariants-of-the-essential-internal-methods

* JSTests/microbenchmarks/proxy-get-miss-handler.js:
* JSTests/microbenchmarks/proxy-get.js:
* JSTests/microbenchmarks/proxy-has-hit.js:
* JSTests/microbenchmarks/proxy-has-miss-handler.js:
* JSTests/microbenchmarks/proxy-has-miss.js:
* JSTests/microbenchmarks/proxy-set-miss-handler.js:
* JSTests/microbenchmarks/proxy-set.js:
* Source/JavaScriptCore/builtins/BuiltinNames.h:
* Source/JavaScriptCore/builtins/ProxyHelpers.js:
(linkTimeConstant.performProxyObjectHas):
(linkTimeConstant.performProxyObjectGet):
(linkTimeConstant.performProxyObjectSetSloppy):
(linkTimeConstant.performProxyObjectSetStrict):
* Source/JavaScriptCore/bytecode/BytecodeIntrinsicRegistry.h:
* Source/JavaScriptCore/bytecode/BytecodeList.rb:
* Source/JavaScriptCore/bytecode/BytecodeUseDef.cpp:
(JSC::computeUsesForBytecodeIndexImpl):
(JSC::computeDefsForBytecodeIndexImpl):
* Source/JavaScriptCore/bytecode/LinkTimeConstant.h:
* Source/JavaScriptCore/bytecompiler/BytecodeGenerator.cpp:
(JSC::BytecodeGenerator::emitHasStructureWithFlags):
* Source/JavaScriptCore/bytecompiler/BytecodeGenerator.h:
* Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp:
(JSC::BytecodeIntrinsicNode::emit_intrinsic_mustValidateResultOfProxyGetAndSetTraps):
(JSC::BytecodeIntrinsicNode::emit_intrinsic_mustValidateResultOfProxyTrapsExceptGetAndSet):
* Source/JavaScriptCore/dfg/DFGAbstractInterpreterInlines.h:
(JSC::DFG::AbstractInterpreter<AbstractStateType>::executeEffects):
* Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp:
(JSC::DFG::ByteCodeParser::parseBlock):
* Source/JavaScriptCore/dfg/DFGClobberize.h:
(JSC::DFG::clobberize):
* Source/JavaScriptCore/dfg/DFGConstantFoldingPhase.cpp:
(JSC::DFG::ConstantFoldingPhase::foldConstants):
* Source/JavaScriptCore/dfg/DFGDoesGC.cpp:
(JSC::DFG::doesGC):
* Source/JavaScriptCore/dfg/DFGFixupPhase.cpp:
(JSC::DFG::FixupPhase::fixupNode):
* Source/JavaScriptCore/dfg/DFGGraph.cpp:
(JSC::DFG::Graph::dump):
* Source/JavaScriptCore/dfg/DFGNode.h:
(JSC::DFG::Node::hasStructureFlags):
(JSC::DFG::Node::structureFlags):
* Source/JavaScriptCore/dfg/DFGNodeType.h:
* Source/JavaScriptCore/dfg/DFGPredictionPropagationPhase.cpp:
* Source/JavaScriptCore/dfg/DFGSafeToExecute.h:
(JSC::DFG::safeToExecute):
* Source/JavaScriptCore/dfg/DFGSpeculativeJIT.cpp:
* Source/JavaScriptCore/dfg/DFGSpeculativeJIT.h:
* Source/JavaScriptCore/dfg/DFGSpeculativeJIT32_64.cpp:
(JSC::DFG::SpeculativeJIT::compile):
* Source/JavaScriptCore/dfg/DFGSpeculativeJIT64.cpp:
(JSC::DFG::SpeculativeJIT::compile):
* Source/JavaScriptCore/ftl/FTLCapabilities.cpp:
(JSC::FTL::canCompile):
* Source/JavaScriptCore/ftl/FTLLowerDFGToB3.cpp:
(JSC::FTL::DFG::LowerDFGToB3::compileNode):
(JSC::FTL::DFG::LowerDFGToB3::compileCompareStrictEq):
* Source/JavaScriptCore/jit/JIT.cpp:
(JSC::JIT::privateCompileMainPass):
* Source/JavaScriptCore/jit/JIT.h:
* Source/JavaScriptCore/jit/JITOpcodes.cpp:
(JSC::JIT::emit_op_has_structure_with_flags):
* Source/JavaScriptCore/llint/LLIntSlowPaths.cpp:
(JSC::LLInt::LLINT_SLOW_PATH_DECL):
* Source/JavaScriptCore/llint/LLIntSlowPaths.h:
* Source/JavaScriptCore/llint/LowLevelInterpreter32_64.asm:
* Source/JavaScriptCore/llint/LowLevelInterpreter64.asm:
* Source/JavaScriptCore/runtime/JSGlobalObject.cpp:
(JSC::JSGlobalObject::init):
* Source/JavaScriptCore/runtime/JSGlobalObjectFunctions.cpp:
(JSC::JSC_DEFINE_HOST_FUNCTION):
(JSC::globalFuncHandleProxySetTrapResult): Deleted.
* Source/JavaScriptCore/runtime/JSGlobalObjectFunctions.h:
* Source/JavaScriptCore/runtime/JSGlobalProxy.h:
* Source/JavaScriptCore/runtime/JSTypeInfo.h:
(JSC::TypeInfo::overridesIsExtensible const):
* Source/JavaScriptCore/runtime/PropertySlot.h:
* Source/JavaScriptCore/runtime/ProxyObject.cpp:
(JSC::ProxyObject::performPut):
(JSC::ProxyObject::validatePositiveSetTrapResult):
(JSC::ProxyObject::validateSetTrapResult): Deleted.
* Source/JavaScriptCore/runtime/ProxyObject.h:
* Source/JavaScriptCore/runtime/Structure.cpp:
(JSC::Structure::validateFlags):
(JSC::Structure::Structure):
(JSC::Structure::nonPropertyTransitionSlow):
* Source/JavaScriptCore/runtime/Structure.h:
(JSC::Structure::isNonExtensibleOrHasNonConfigurableProperties const):
(JSC::Structure::hasAnyOfBitFieldFlags const):
(JSC::Structure::bitFieldFlagsCantBeChangedWithoutTransition):
* Source/JavaScriptCore/runtime/StructureInlines.h:
(JSC::Structure::add):
(JSC::Structure::attributeChange):
* Source/JavaScriptCore/wasm/js/WebAssemblyGCObjectBase.h:
* Source/WebCore/bindings/js/JSDOMWindowProperties.h:

Canonical link: https://commits.webkit.org/263571@main

101adf2

Misc iOS, tvOS & watchOS macOS Linux Windows
❌ πŸ§ͺ style βœ… πŸ›  ios βœ… πŸ›  mac βœ… πŸ›  wpe βœ… πŸ›  wincairo
βœ… πŸ§ͺ bindings βœ… πŸ›  ios-sim βœ… πŸ›  mac-AS-debug βœ… πŸ§ͺ wpe-wk2
βœ… πŸ§ͺ webkitperl βœ… πŸ§ͺ ios-wk2 βœ… πŸ§ͺ api-mac βœ… πŸ›  gtk
βœ… πŸ§ͺ ios-wk2-wpt βœ… πŸ§ͺ mac-wk1 βœ… πŸ§ͺ gtk-wk2
βœ… πŸ›  πŸ§ͺ jsc βœ… πŸ§ͺ api-ios βœ… πŸ§ͺ mac-wk2 βœ… πŸ§ͺ api-gtk
βœ… πŸ›  πŸ§ͺ jsc-arm64 βœ… πŸ›  tv βœ… πŸ§ͺ mac-AS-debug-wk2 βœ… πŸ›  jsc-armv7
βœ… πŸ›  tv-sim βœ… πŸ§ͺ jsc-armv7-tests
βœ… πŸ›  watch βœ… πŸ›  jsc-mips
βœ… πŸ›  πŸ§ͺ unsafe-merge βœ… πŸ›  watch-sim βœ… πŸ§ͺ jsc-mips-tests

@shvaikalesh shvaikalesh requested review from cdumez and a team as code owners May 2, 2023 03:37
@shvaikalesh shvaikalesh self-assigned this May 2, 2023
@shvaikalesh shvaikalesh added the JavaScriptCore For bugs in JavaScriptCore, the JS engine used by WebKit, other than kxmlcore issues. label May 2, 2023
@shvaikalesh shvaikalesh removed request for a team and cdumez May 2, 2023 03:45
@shvaikalesh shvaikalesh added the unsafe-merge-queue Applied to send a pull request to merge-queue, but skip building and testing label May 2, 2023
https://bugs.webkit.org/show_bug.cgi?id=255661
<rdar://problem/108269769>

Reviewed by Yusuke Suzuki.

Invariants of the essential internal methods [1] are enforced for all objects, both ordinary and exotic,
to avoid them having unpredictable behavior that negatively impacts developer experience and creates
security issues.

Enforcing them for Proxy objects is especially cumbersome, given traps are userland code, and quite
expensive performance-wise: invariants invalidation requires checking property attributes,
which currently requires JS => C++ call.

After carefully analyzing all the invariants of the all internal methods, it was concluded that if
[[ProxyTarget]] is an ordinary extensible object without non-configurable properties, validation of
the invariants can be safely (non-observably) skipped.

trap name                   IC    attributes checked
========================    ==    ==================================
getOwnPropertyDescriptor    no    non-configurable || non-extensible
defineProperty              no    non-configurable || non-extensible
has                        yes    non-configurable || non-extensible
get                        yes    non-configurable && (non-writable || accessor)
set                        yes    non-configurable && (non-writable || accessor)
deleteProperty           maybe    non-configurable || non-extensible
ownKeys                     no    non-configurable || non-extensible

This change:

  1. Introduces OverridesIsExtensible out-of-line type info flag to tighten Structure's didPreventExtensions
     flag, making it more pessimistic: it being `true` doesn't necessarily mean the structure is non-extensible,
     but the reverse (it being `false`) can be safely relied on.

     It's not a completely new approach: WebKit#11843 does the same thing.

     This change was proven not to introduce bugs since Structure's didPreventExtensions flag is currently
     relied upon only for objects without isExtensible() override.

  2. Introduces hasNonConfigurableProperties and hasNonConfigurableReadOnlyOrGetterSetterProperties Structure
     flags that are also pessimistic.

     When inferring their initial values, we do extra care not to be overly pessimistic for objects except
     JSFinalObject by checking overridesGetOwnPropertySlot() so that userland code, which heavily uses
     Map / Set as [[ProxyTarget]], is also performant, while making an exception for JSArray's non-configurable
     non-structure "length" property.

     While there is existing hasReadOnlyOrGetterSetterPropertiesExcludingProto flag, we can't combine it with
     hasNonConfigurableProperties because MobX installs a non-writable administration property even on arrays,
     which have non-configurable "length" already, so combining them would disable optimization for JSArray.

  3. Introduces HasStructureWithFlags bytecode op to be utilized in ProxyObject IC helpers to skip trap result
     validation for most of ProxyObject's targets. In the follow-ups, this approach will be expanded to C++ code.

Currently, due to lack of proper profiling of GetInternalField results, constant folding for HasStructureWithFlags
doesn't happen in microbenchmarks.

                                   ToT                      patch

proxy-has-miss              159.9825+-2.4190     ^     43.1435+-0.5994        ^ definitely 3.7082x faster
proxy-set-miss-handler      158.7617+-2.3615     ^    139.2158+-1.9197        ^ definitely 1.1404x faster
proxy-set                   125.5967+-1.3678     ^     14.4533+-0.1739        ^ definitely 8.6898x faster
proxy-get                   115.8061+-2.2413     ^     14.2136+-0.1138        ^ definitely 8.1475x faster

<geometric>                 138.5985+-0.9526     ^     33.3237+-0.2255        ^ definitely 4.1592x faster

[1]: https://tc39.es/ecma262/#sec-invariants-of-the-essential-internal-methods

* JSTests/microbenchmarks/proxy-get-miss-handler.js:
* JSTests/microbenchmarks/proxy-get.js:
* JSTests/microbenchmarks/proxy-has-hit.js:
* JSTests/microbenchmarks/proxy-has-miss-handler.js:
* JSTests/microbenchmarks/proxy-has-miss.js:
* JSTests/microbenchmarks/proxy-set-miss-handler.js:
* JSTests/microbenchmarks/proxy-set.js:
* Source/JavaScriptCore/builtins/BuiltinNames.h:
* Source/JavaScriptCore/builtins/ProxyHelpers.js:
(linkTimeConstant.performProxyObjectHas):
(linkTimeConstant.performProxyObjectGet):
(linkTimeConstant.performProxyObjectSetSloppy):
(linkTimeConstant.performProxyObjectSetStrict):
* Source/JavaScriptCore/bytecode/BytecodeIntrinsicRegistry.h:
* Source/JavaScriptCore/bytecode/BytecodeList.rb:
* Source/JavaScriptCore/bytecode/BytecodeUseDef.cpp:
(JSC::computeUsesForBytecodeIndexImpl):
(JSC::computeDefsForBytecodeIndexImpl):
* Source/JavaScriptCore/bytecode/LinkTimeConstant.h:
* Source/JavaScriptCore/bytecompiler/BytecodeGenerator.cpp:
(JSC::BytecodeGenerator::emitHasStructureWithFlags):
* Source/JavaScriptCore/bytecompiler/BytecodeGenerator.h:
* Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp:
(JSC::BytecodeIntrinsicNode::emit_intrinsic_mustValidateResultOfProxyGetAndSetTraps):
(JSC::BytecodeIntrinsicNode::emit_intrinsic_mustValidateResultOfProxyTrapsExceptGetAndSet):
* Source/JavaScriptCore/dfg/DFGAbstractInterpreterInlines.h:
(JSC::DFG::AbstractInterpreter<AbstractStateType>::executeEffects):
* Source/JavaScriptCore/dfg/DFGByteCodeParser.cpp:
(JSC::DFG::ByteCodeParser::parseBlock):
* Source/JavaScriptCore/dfg/DFGClobberize.h:
(JSC::DFG::clobberize):
* Source/JavaScriptCore/dfg/DFGConstantFoldingPhase.cpp:
(JSC::DFG::ConstantFoldingPhase::foldConstants):
* Source/JavaScriptCore/dfg/DFGDoesGC.cpp:
(JSC::DFG::doesGC):
* Source/JavaScriptCore/dfg/DFGFixupPhase.cpp:
(JSC::DFG::FixupPhase::fixupNode):
* Source/JavaScriptCore/dfg/DFGGraph.cpp:
(JSC::DFG::Graph::dump):
* Source/JavaScriptCore/dfg/DFGNode.h:
(JSC::DFG::Node::hasStructureFlags):
(JSC::DFG::Node::structureFlags):
* Source/JavaScriptCore/dfg/DFGNodeType.h:
* Source/JavaScriptCore/dfg/DFGPredictionPropagationPhase.cpp:
* Source/JavaScriptCore/dfg/DFGSafeToExecute.h:
(JSC::DFG::safeToExecute):
* Source/JavaScriptCore/dfg/DFGSpeculativeJIT.cpp:
* Source/JavaScriptCore/dfg/DFGSpeculativeJIT.h:
* Source/JavaScriptCore/dfg/DFGSpeculativeJIT32_64.cpp:
(JSC::DFG::SpeculativeJIT::compile):
* Source/JavaScriptCore/dfg/DFGSpeculativeJIT64.cpp:
(JSC::DFG::SpeculativeJIT::compile):
* Source/JavaScriptCore/ftl/FTLCapabilities.cpp:
(JSC::FTL::canCompile):
* Source/JavaScriptCore/ftl/FTLLowerDFGToB3.cpp:
(JSC::FTL::DFG::LowerDFGToB3::compileNode):
(JSC::FTL::DFG::LowerDFGToB3::compileCompareStrictEq):
* Source/JavaScriptCore/jit/JIT.cpp:
(JSC::JIT::privateCompileMainPass):
* Source/JavaScriptCore/jit/JIT.h:
* Source/JavaScriptCore/jit/JITOpcodes.cpp:
(JSC::JIT::emit_op_has_structure_with_flags):
* Source/JavaScriptCore/llint/LLIntSlowPaths.cpp:
(JSC::LLInt::LLINT_SLOW_PATH_DECL):
* Source/JavaScriptCore/llint/LLIntSlowPaths.h:
* Source/JavaScriptCore/llint/LowLevelInterpreter32_64.asm:
* Source/JavaScriptCore/llint/LowLevelInterpreter64.asm:
* Source/JavaScriptCore/runtime/JSGlobalObject.cpp:
(JSC::JSGlobalObject::init):
* Source/JavaScriptCore/runtime/JSGlobalObjectFunctions.cpp:
(JSC::JSC_DEFINE_HOST_FUNCTION):
(JSC::globalFuncHandleProxySetTrapResult): Deleted.
* Source/JavaScriptCore/runtime/JSGlobalObjectFunctions.h:
* Source/JavaScriptCore/runtime/JSGlobalProxy.h:
* Source/JavaScriptCore/runtime/JSTypeInfo.h:
(JSC::TypeInfo::overridesIsExtensible const):
* Source/JavaScriptCore/runtime/PropertySlot.h:
* Source/JavaScriptCore/runtime/ProxyObject.cpp:
(JSC::ProxyObject::performPut):
(JSC::ProxyObject::validatePositiveSetTrapResult):
(JSC::ProxyObject::validateSetTrapResult): Deleted.
* Source/JavaScriptCore/runtime/ProxyObject.h:
* Source/JavaScriptCore/runtime/Structure.cpp:
(JSC::Structure::validateFlags):
(JSC::Structure::Structure):
(JSC::Structure::nonPropertyTransitionSlow):
* Source/JavaScriptCore/runtime/Structure.h:
(JSC::Structure::isNonExtensibleOrHasNonConfigurableProperties const):
(JSC::Structure::hasAnyOfBitFieldFlags const):
(JSC::Structure::bitFieldFlagsCantBeChangedWithoutTransition):
* Source/JavaScriptCore/runtime/StructureInlines.h:
(JSC::Structure::add):
(JSC::Structure::attributeChange):
* Source/JavaScriptCore/wasm/js/WebAssemblyGCObjectBase.h:
* Source/WebCore/bindings/js/JSDOMWindowProperties.h:

Canonical link: https://commits.webkit.org/263571@main
@webkit-commit-queue
Copy link
Collaborator

Committed 263571@main (052608b): https://commits.webkit.org/263571@main

Reviewed commits have been landed. Closing PR #13349 and removing active labels.

@webkit-commit-queue webkit-commit-queue merged commit 052608b into WebKit:main May 2, 2023
@webkit-commit-queue webkit-commit-queue removed the unsafe-merge-queue Applied to send a pull request to merge-queue, but skip building and testing label May 2, 2023
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
JavaScriptCore For bugs in JavaScriptCore, the JS engine used by WebKit, other than kxmlcore issues.
Projects
None yet
3 participants