runtime/VMEntryScope.cpp

   1 /*
   2  * Copyright (C) 2013, 2014 Apple Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "config.h"
  27 #include "VMEntryScope.h"
  28
  29 #include "Debugger.h"
  30 #include "Options.h"
  31 #include "VM.h"
  32 #include <wtf/StackBounds.h>
  33
  34 namespace JSC {
  35
  36 VMEntryScope::VMEntryScope(VM& vm, JSGlobalObject* globalObject)
  37     : m_vm(vm)
  38     , m_globalObject(globalObject)
  39     , m_recompilationNeeded(false)
  40 {
  41     ASSERT(wtfThreadData().stack().isGrowingDownward());
  42     if (!vm.entryScope) {
  43 #if ENABLE(ASSEMBLER)
  44         if (ExecutableAllocator::underMemoryPressure())
  45             vm.heap.deleteAllCompiledCode();
  46 #endif
  47         vm.entryScope = this;
  48
  49         // Reset the date cache between JS invocations to force the VM to
  50         // observe time xone changes.
  51         vm.resetDateCache();
  52     }
  53
  54     // Clear the captured exception stack between entries
  55     vm.clearExceptionStack();
  56 }
  57
  58 VMEntryScope::~VMEntryScope()
  59 {
  60     if (m_vm.entryScope != this)
  61         return;
  62
  63     m_vm.entryScope = nullptr;
  64
  65     if (m_recompilationNeeded) {
  66         if (Debugger* debugger = m_globalObject->debugger())
  67             debugger->recompileAllJSFunctions(&m_vm);
  68     }
  69 }
  70
  71 } // namespace JSC