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Add JSVirtualMachine SPI to shrink the memory footprint of the VM
https://bugs.webkit.org/show_bug.cgi?id=185441 <rdar://problem/39999414> Reviewed by Keith Miller. This patch adds JSVirtualMachine SPI to release as much memory as possible. The SPI does: - Deletes all code caches. - Synchronous GC. - Run the scavenger. * API/JSVirtualMachine.mm: (-[JSVirtualMachine shrinkFootprint]): * API/JSVirtualMachinePrivate.h: Added. * API/tests/testapi.mm: (testObjectiveCAPIMain): * JavaScriptCore.xcodeproj/project.pbxproj: * runtime/VM.cpp: (JSC::VM::shrinkFootprint): * runtime/VM.h: Canonical link: https://commits.webkit.org/200963@main git-svn-id: https://svn.webkit.org/repository/webkit/trunk@231589 268f45cc-cd09-0410-ab3c-d52691b4dbfc
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‎Source/JavaScriptCore/API/JSVirtualMachine.mm‎

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@@ -268,6 +268,13 @@ - (NSMapTable *)externalRememberedSet
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return m_externalRememberedSet;
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}
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- (void)shrinkFootprint
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{
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JSC::VM* vm = toJS(m_group);
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JSC::JSLockHolder locker(vm);
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vm->shrinkFootprint();
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}
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@end
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static void scanExternalObjectGraph(JSC::VM& vm, JSC::SlotVisitor& visitor, void* root, bool lockAcquired)

‎Source/JavaScriptCore/API/JSVirtualMachinePrivate.h‎

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/*
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* Copyright (C) 2018 Apple Inc. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
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* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <JavaScriptCore/JavaScript.h>
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#if JSC_OBJC_API_ENABLED
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#import <JavaScriptCore/JSVirtualMachine.h>
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@interface JSVirtualMachine(JSPrivate)
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/*!
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@method
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@discussion Shrinks the memory footprint of the VM by deleting various internal caches,
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running synchronous garbage collection, and releasing memory back to the OS. For this
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to free as much memory as possible, do not call this when JavaScript is running on the stack.
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*/
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- (void)shrinkFootprint; // FIXME: Annotate this with NS_AVAILABLE: <rdar://problem/40071332>.
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@end
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#endif // JSC_OBJC_API_ENABLED

‎Source/JavaScriptCore/API/tests/testapi.mm‎

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#import "CurrentThisInsideBlockGetterTest.h"
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#import "DateTests.h"
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#import "JSExportTests.h"
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#import "JSVirtualMachinePrivate.h"
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#import "Regress141275.h"
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#import "Regress141809.h"
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#import <pthread.h>
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#import <vector>
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#import <wtf/MemoryFootprint.h>
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#import <wtf/Optional.h>
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extern "C" void JSSynchronousGarbageCollectForDebugging(JSContextRef);
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extern "C" void JSSynchronousEdenCollectForDebugging(JSContextRef);
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checkResult(@"Ran code in five concurrent VMs that GC'd", ok);
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}
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@autoreleasepool {
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JSContext *context = [[JSContext alloc] init];
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JSVirtualMachine *vm = [context virtualMachine];
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[vm shrinkFootprint]; // Make sure that when we allocate a ton of memory below we reuse at little as possible.
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std::optional<size_t> footprintBefore = WTF::memoryFootprint();
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RELEASE_ASSERT(footprintBefore);
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[context evaluateScript:@"for (let i = 0; i < 10000; ++i) { eval(`myVariable_${i} = [i]`); }"];
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static constexpr size_t approximateBytes = 10000 * sizeof(int);
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std::optional<size_t> footprintMiddle = WTF::memoryFootprint();
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RELEASE_ASSERT(footprintMiddle);
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checkResult(@"Footprint is larger than what we allocated", *footprintMiddle > approximateBytes);
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checkResult(@"Footprint got larger as we allocated a ton of stuff", *footprintMiddle > *footprintBefore);
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size_t allocationDelta = *footprintMiddle - *footprintBefore;
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checkResult(@"We allocated as much or more memory than what we expected to", allocationDelta >= approximateBytes);
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[context evaluateScript:@"for (let i = 0; i < 10000; ++i) { eval(`myVariable_${i} = null`); }"];
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[vm shrinkFootprint];
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std::optional<size_t> footprintAfter = WTF::memoryFootprint();
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RELEASE_ASSERT(footprintAfter);
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checkResult(@"Footprint got smaller after we shrank the VM", *footprintAfter < *footprintMiddle);
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size_t freeDelta = *footprintMiddle - *footprintAfter;
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checkResult(@"Shrinking the footprint of the VM actually freed memory", freeDelta > (approximateBytes / 2));
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}
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currentThisInsideBlockGetterTest();
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runDateTests();
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runJSExportTests();

‎Source/JavaScriptCore/ChangeLog‎

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2018-05-09 Saam Barati <sbarati@apple.com>
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Add JSVirtualMachine SPI to shrink the memory footprint of the VM
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https://bugs.webkit.org/show_bug.cgi?id=185441
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<rdar://problem/39999414>
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Reviewed by Keith Miller.
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This patch adds JSVirtualMachine SPI to release as much memory as possible.
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The SPI does:
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- Deletes all code caches.
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- Synchronous GC.
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- Run the scavenger.
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* API/JSVirtualMachine.mm:
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(-[JSVirtualMachine shrinkFootprint]):
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* API/JSVirtualMachinePrivate.h: Added.
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* API/tests/testapi.mm:
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(testObjectiveCAPIMain):
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* JavaScriptCore.xcodeproj/project.pbxproj:
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* runtime/VM.cpp:
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(JSC::VM::shrinkFootprint):
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* runtime/VM.h:
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2018-05-09 Leo Balter <leonardo.balter@gmail.com>
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[JSC] Fix ArraySpeciesCreate to return a new Array when the given object is not an array

‎Source/JavaScriptCore/JavaScriptCore.xcodeproj/project.pbxproj‎

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7919B7801E03559C005BEED8 /* B3Compile.h in Headers */ = {isa = PBXBuildFile; fileRef = 7919B77F1E03559C005BEED8 /* B3Compile.h */; settings = {ATTRIBUTES = (Private, ); }; };
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79233C2B1D34715700C5A834 /* JITMathIC.h in Headers */ = {isa = PBXBuildFile; fileRef = 79233C291D34715700C5A834 /* JITMathIC.h */; settings = {ATTRIBUTES = (Private, ); }; };
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792CB34A1C4EED5C00D13AF3 /* PCToCodeOriginMap.h in Headers */ = {isa = PBXBuildFile; fileRef = 792CB3481C4EED5C00D13AF3 /* PCToCodeOriginMap.h */; settings = {ATTRIBUTES = (Private, ); }; };
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795AC61820A2355E0052C76C /* JSVirtualMachinePrivate.h in Headers */ = {isa = PBXBuildFile; fileRef = 795AC61720A2354B0052C76C /* JSVirtualMachinePrivate.h */; settings = {ATTRIBUTES = (Private, ); }; };
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7964656A1B952FF0003059EE /* GetPutInfo.h in Headers */ = {isa = PBXBuildFile; fileRef = 796465681B952FF0003059EE /* GetPutInfo.h */; settings = {ATTRIBUTES = (Private, ); }; };
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7965C2171E5D799600B7591D /* AirAllocateRegistersByGraphColoring.h in Headers */ = {isa = PBXBuildFile; fileRef = 7965C2151E5D799600B7591D /* AirAllocateRegistersByGraphColoring.h */; settings = {ATTRIBUTES = (Private, ); }; };
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796DAA2B1E89CCD6005DF24A /* CalleeBits.h in Headers */ = {isa = PBXBuildFile; fileRef = 796DAA2A1E89CCD6005DF24A /* CalleeBits.h */; settings = {ATTRIBUTES = (Private, ); }; };
@@ -3611,6 +3612,7 @@
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79233C291D34715700C5A834 /* JITMathIC.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = JITMathIC.h; sourceTree = "<group>"; };
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792CB3471C4EED5C00D13AF3 /* PCToCodeOriginMap.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = PCToCodeOriginMap.cpp; sourceTree = "<group>"; };
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792CB3481C4EED5C00D13AF3 /* PCToCodeOriginMap.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = PCToCodeOriginMap.h; sourceTree = "<group>"; };
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795AC61720A2354B0052C76C /* JSVirtualMachinePrivate.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = JSVirtualMachinePrivate.h; sourceTree = "<group>"; };
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795F099C1E03600500BBE37F /* B3Compile.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = B3Compile.cpp; path = b3/B3Compile.cpp; sourceTree = "<group>"; };
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796465681B952FF0003059EE /* GetPutInfo.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = GetPutInfo.h; sourceTree = "<group>"; };
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7965C2141E5D799600B7591D /* AirAllocateRegistersByGraphColoring.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = AirAllocateRegistersByGraphColoring.cpp; path = b3/air/AirAllocateRegistersByGraphColoring.cpp; sourceTree = "<group>"; };
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14BD5A2B0A3E91F600BAF59C /* JSValueRef.cpp */,
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1482B6EA0A4300B300517CFC /* JSValueRef.h */,
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86E3C60F167BAB87006D760A /* JSVirtualMachine.h */,
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795AC61720A2354B0052C76C /* JSVirtualMachinePrivate.h */,
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86E3C610167BAB87006D760A /* JSVirtualMachine.mm */,
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86E3C611167BAB87006D760A /* JSVirtualMachineInternal.h */,
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A7482E37116A697B003B0712 /* JSWeakObjectMapRefInternal.h */,
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0FFB921C16D02F110055A5DB /* DFGOSRExitCompilationInfo.h in Headers */,
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0F7025AA1714B0FC00382C0E /* DFGOSRExitCompilerCommon.h in Headers */,
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0F392C8A1B46188400844728 /* DFGOSRExitFuzz.h in Headers */,
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795AC61820A2355E0052C76C /* JSVirtualMachinePrivate.h in Headers */,
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0FEFC9AB1681A3B600567F53 /* DFGOSRExitJumpPlaceholder.h in Headers */,
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0F235BEE17178E7300690C7F /* DFGOSRExitPreparation.h in Headers */,
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0F6237981AE45CA700D402EA /* DFGPhantomInsertionPhase.h in Headers */,

‎Source/JavaScriptCore/runtime/VM.cpp‎

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@@ -771,6 +771,16 @@ void VM::deleteAllCode(DeleteAllCodeEffort effort)
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});
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}
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void VM::shrinkFootprint()
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{
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sanitizeStackForVM(this);
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deleteAllCode(DeleteAllCodeIfNotCollecting);
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heap.collectSync();
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WTF::releaseFastMallocFreeMemory();
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// FIXME: Consider stopping various automatic threads here.
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// https://bugs.webkit.org/show_bug.cgi?id=185447
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}
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SourceProviderCache* VM::addSourceProviderCache(SourceProvider* sourceProvider)
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{
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auto addResult = sourceProviderCacheMap.add(sourceProvider, nullptr);

‎Source/JavaScriptCore/runtime/VM.h‎

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@@ -746,6 +746,8 @@ class VM : public ThreadSafeRefCounted<VM>, public DoublyLinkedListNode<VM> {
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JS_EXPORT_PRIVATE void deleteAllCode(DeleteAllCodeEffort);
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JS_EXPORT_PRIVATE void deleteAllLinkedCode(DeleteAllCodeEffort);
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void shrinkFootprint();
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WatchpointSet* ensureWatchpointSetForImpureProperty(const Identifier&);
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void registerWatchpointForImpureProperty(const Identifier&, Watchpoint*);
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