[MERGE #4503 @thomasmo] 18-01 Security Update

Merge pull request #4503 from thomasmo:1801 18-01 Security Update that addresses the following issues in ChakraCore: CVE-2018-0758 CVE-2018-0762 CVE-2018-0767 CVE-2018-0768 CVE-2018-0769 CVE-2018-0770 CVE-2018-0772 CVE-2018-0773 CVE-2018-0774 CVE-2018-0775 CVE-2018-0776 CVE-2018-0777 CVE-2018-0778 CVE-2018-0780 CVE-2018-0781
chakra-core · Jan 5, 2018 · e02b39a · e02b39a
2 parents c6d73ba + 7b59f02
commit e02b39a
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Showing 46 changed files with 480 additions and 163 deletions.
diff --git a/Build/NuGet/.pack-version b/Build/NuGet/.pack-version
@@ -1 +1 @@
-1.7.5
+1.7.6
diff --git a/lib/Backend/BailOut.cpp b/lib/Backend/BailOut.cpp
@@ -1006,7 +1006,7 @@ BailOutRecord::RestoreValue(IR::BailOutKind bailOutKind, Js::JavascriptCallStack
         if (boxStackInstance)
         {
             Js::Var oldValue = value;
-            value = Js::JavascriptOperators::BoxStackInstance(oldValue, scriptContext, /* allowStackFunction */ true);
+            value = Js::JavascriptOperators::BoxStackInstance(oldValue, scriptContext, /* allowStackFunction */ true, /* deepCopy */ false);
 
             if (oldValue != value)
             {
@@ -1275,7 +1275,7 @@ BailOutRecord::BailOutInlinedHelper(Js::JavascriptCallStackLayout * layout, Bail
         if (inlineeFrameRecord)
         {
             InlinedFrameLayout* outerMostFrame = (InlinedFrameLayout *)(((uint8 *)Js::JavascriptCallStackLayout::ToFramePointer(layout)) - entryPointInfo->frameHeight);
-            inlineeFrameRecord->RestoreFrames(functionBody, outerMostFrame, layout);
+            inlineeFrameRecord->RestoreFrames(functionBody, outerMostFrame, layout, false /* deepCopy */);
         }
     }
 
@@ -1480,7 +1480,7 @@ BailOutRecord::BailOutHelper(Js::JavascriptCallStackLayout * layout, Js::ScriptF
         {
             const Js::Var arg = args.Values[i];
             BAILOUT_VERBOSE_TRACE(executeFunction, bailOutKind, _u("BailOut:   Argument #%3u: value: 0x%p"), i, arg);
-            const Js::Var boxedArg = Js::JavascriptOperators::BoxStackInstance(arg, functionScriptContext, true);
+            const Js::Var boxedArg = Js::JavascriptOperators::BoxStackInstance(arg, functionScriptContext, /* allowStackFunction */ true, /* deepCopy */ false);
             if(boxedArg != arg)
             {
                 args.Values[i] = boxedArg;
@@ -1775,7 +1775,7 @@ BailOutRecord::BailOutHelper(Js::JavascriptCallStackLayout * layout, Js::ScriptF
         aReturn = Js::JavascriptFunction::FinishConstructor(aReturn, args.Values[0], function);
 
         Js::Var oldValue = aReturn;
-        aReturn = Js::JavascriptOperators::BoxStackInstance(oldValue, functionScriptContext, /* allowStackFunction */ true);
+        aReturn = Js::JavascriptOperators::BoxStackInstance(oldValue, functionScriptContext, /* allowStackFunction */ true, /* deepCopy */ false);
 #if ENABLE_DEBUG_CONFIG_OPTIONS
         if (oldValue != aReturn)
         {

diff --git a/lib/Backend/GlobOpt.cpp b/lib/Backend/GlobOpt.cpp
@@ -2859,7 +2859,7 @@ GlobOpt::OptTagChecks(IR::Instr *instr)
 
             if (valueType.CanBeTaggedValue() &&
                 !valueType.HasBeenNumber() &&
-                (this->IsLoopPrePass() || !this->currentBlock->loop))
+                !this->IsLoopPrePass())
             {
                 ValueType newValueType = valueType.SetCanBeTaggedValue(false);
 
@@ -2883,7 +2883,16 @@ GlobOpt::OptTagChecks(IR::Instr *instr)
                 bailOutInstr->SetSrc1(srcOpnd);
                 bailOutInstr->GetSrc1()->SetValueType(valueType);
                 instr->InsertBefore(bailOutInstr);
-
+                if (this->currentBlock->loop)
+                {
+                    // Try hoisting the BailOnNotObject instr.
+                    // But since this isn't the current instr being optimized, we need to play tricks with
+                    // the byteCodeUse fields...
+                    TrackByteCodeUsesForInstrAddedInOptInstr(bailOutInstr, [&]()
+                    {
+                        TryHoistInvariant(bailOutInstr, this->currentBlock, nullptr, value, nullptr, true, false, false, IR::BailOutOnTaggedValue);
+                    });
+                }
                 if (symOpnd)
                 {
                     symOpnd->SetPropertyOwnerValueType(newValueType);
@@ -3968,25 +3977,10 @@ GlobOpt::CopyPropReplaceOpnd(IR::Instr * instr, IR::Opnd * opnd, StackSym * copy
                     // Try hoisting this checkObjType.
                     // But since this isn't the current instr being optimized, we need to play tricks with
                     // the byteCodeUse fields...
-                    BVSparse<JitArenaAllocator> *currentBytecodeUses = this->byteCodeUses;
-                    PropertySym * currentPropertySymUse = this->propertySymUse;
-                    PropertySym * tempPropertySymUse = NULL;
-                    this->byteCodeUses = NULL;
-                    BVSparse<JitArenaAllocator> *tempByteCodeUse = JitAnew(this->tempAlloc, BVSparse<JitArenaAllocator>, this->tempAlloc);
-#if DBG
-                    BVSparse<JitArenaAllocator> *currentBytecodeUsesBeforeOpt = this->byteCodeUsesBeforeOpt;
-                    this->byteCodeUsesBeforeOpt = tempByteCodeUse;
-#endif
-                    this->propertySymUse = NULL;
-                    GlobOpt::TrackByteCodeSymUsed(checkObjTypeInstr, tempByteCodeUse, &tempPropertySymUse);
-
-                    TryHoistInvariant(checkObjTypeInstr, this->currentBlock, NULL, CurrentBlockData()->FindValue(copySym), NULL, true);
-
-                    this->byteCodeUses = currentBytecodeUses;
-                    this->propertySymUse = currentPropertySymUse;
-#if DBG
-                    this->byteCodeUsesBeforeOpt = currentBytecodeUsesBeforeOpt;
-#endif
+                    TrackByteCodeUsesForInstrAddedInOptInstr(checkObjTypeInstr, [&]()
+                    {
+                        TryHoistInvariant(checkObjTypeInstr, this->currentBlock, NULL, CurrentBlockData()->FindValue(copySym), NULL, true);
+                    });
                 }
             }
         }
@@ -7072,6 +7066,18 @@ GlobOpt::OptConstFoldUnary(
             this->ToFloat64Dst(instr, dst->AsRegOpnd(), this->currentBlock);
         }
     }
+
+    // If this is an induction variable, then treat it the way the prepass would have if it had seen
+    // the assignment and the resulting change to the value number, and mark it as indeterminate.
+    for (Loop * loop = this->currentBlock->loop; loop; loop = loop->parent)
+    {
+        InductionVariable *iv = nullptr;
+        if (loop->inductionVariables && loop->inductionVariables->TryGetReference(dstSym->m_id, &iv))
+        {
+            iv->SetChangeIsIndeterminate();
+        }
+    }
+
     return true;
 }
 
@@ -12391,6 +12397,17 @@ GlobOpt::OptConstFoldBinary(
         this->ToInt32Dst(instr, dst->AsRegOpnd(), this->currentBlock);
     }
 
+    // If this is an induction variable, then treat it the way the prepass would have if it had seen
+    // the assignment and the resulting change to the value number, and mark it as indeterminate.
+    for (Loop * loop = this->currentBlock->loop; loop; loop = loop->parent)
+    {
+        InductionVariable *iv = nullptr;
+        if (loop->inductionVariables && loop->inductionVariables->TryGetReference(dstSym->m_id, &iv))
+        {
+            iv->SetChangeIsIndeterminate();
+        }
+    }
+
     return true;
 }
 

diff --git a/lib/Backend/GlobOpt.h b/lib/Backend/GlobOpt.h
@@ -798,6 +798,29 @@ class GlobOpt
     bool                    DoPowIntIntTypeSpec() const;
     bool                    DoTagChecks() const;
 
+    template <class Fn>
+    void TrackByteCodeUsesForInstrAddedInOptInstr(IR::Instr * trackByteCodeUseOnInstr, Fn fn)
+    {
+        BVSparse<JitArenaAllocator> *currentBytecodeUses = this->byteCodeUses;
+        PropertySym * currentPropertySymUse = this->propertySymUse;
+        PropertySym * tempPropertySymUse = NULL;
+        this->byteCodeUses = NULL;
+        BVSparse<JitArenaAllocator> *tempByteCodeUse = JitAnew(this->tempAlloc, BVSparse<JitArenaAllocator>, this->tempAlloc);
+#if DBG
+        BVSparse<JitArenaAllocator> *currentBytecodeUsesBeforeOpt = this->byteCodeUsesBeforeOpt;
+        this->byteCodeUsesBeforeOpt = tempByteCodeUse;
+#endif
+        this->propertySymUse = NULL;
+        GlobOpt::TrackByteCodeSymUsed(trackByteCodeUseOnInstr, tempByteCodeUse, &tempPropertySymUse);
+
+        fn();
+
+        this->byteCodeUses = currentBytecodeUses;
+        this->propertySymUse = currentPropertySymUse;
+#if DBG
+        this->byteCodeUsesBeforeOpt = currentBytecodeUsesBeforeOpt;
+#endif
+    }
 private:
     // GlobOptBailout.cpp
     bool                    MayNeedBailOut(Loop * loop) const;

diff --git a/lib/Backend/GlobOptIntBounds.cpp b/lib/Backend/GlobOptIntBounds.cpp
@@ -840,7 +840,7 @@ void GlobOpt::TrackIntSpecializedAddSubConstant(
             }
         } while(false);
 
-        if(updateSourceBounds && addSubConstantInfo->Offset() != IntConstMin)
+        if(!this->IsLoopPrePass() && updateSourceBounds && addSubConstantInfo->Offset() != IntConstMin)
         {
             // Track bounds for add or sub with a constant. For instance, consider (b = a + 2). The value of 'b' should track
             // that it is equal to (the value of 'a') + 2. That part has been done above. Similarly, the value of 'a' should

diff --git a/lib/Backend/InlineeFrameInfo.cpp b/lib/Backend/InlineeFrameInfo.cpp
@@ -199,13 +199,14 @@ void InlineeFrameRecord::Finalize(Func* inlinee, uint32 currentOffset)
     Assert(this->inlineDepth != 0);
 }
 
-void InlineeFrameRecord::Restore(Js::FunctionBody* functionBody, InlinedFrameLayout *inlinedFrame, Js::JavascriptCallStackLayout * layout) const
+void InlineeFrameRecord::Restore(Js::FunctionBody* functionBody, InlinedFrameLayout *inlinedFrame, Js::JavascriptCallStackLayout * layout, bool deepCopy) const
 {
     Assert(this->inlineDepth != 0);
     Assert(inlineeStartOffset != 0);
 
     BAILOUT_VERBOSE_TRACE(functionBody, _u("Restore function object: "));
-    Js::Var varFunction =  this->Restore(this->functionOffset, /*isFloat64*/ false, /*isInt32*/ false, layout, functionBody);
+    // No deepCopy needed for just the function
+    Js::Var varFunction = this->Restore(this->functionOffset, /*isFloat64*/ false, /*isInt32*/ false, layout, functionBody, /*deepCopy*/ false);
     Assert(Js::ScriptFunction::Is(varFunction));
 
     Js::ScriptFunction* function = Js::ScriptFunction::FromVar(varFunction);
@@ -219,7 +220,9 @@ void InlineeFrameRecord::Restore(Js::FunctionBody* functionBody, InlinedFrameLay
         bool isInt32 = losslessInt32Args.Test(i) != 0;
         BAILOUT_VERBOSE_TRACE(functionBody, _u("Restore argument %d: "), i);
 
-        Js::Var var = this->Restore(this->argOffsets[i], isFloat64, isInt32, layout, functionBody);
+        // Forward deepCopy flag for the arguments in case their data must be guaranteed
+        // to have its own lifetime
+        Js::Var var = this->Restore(this->argOffsets[i], isFloat64, isInt32, layout, functionBody, deepCopy);
 #if DBG
         if (!Js::TaggedNumber::Is(var))
         {
@@ -233,7 +236,7 @@ void InlineeFrameRecord::Restore(Js::FunctionBody* functionBody, InlinedFrameLay
     BAILOUT_FLUSH(functionBody);
 }
 
-void InlineeFrameRecord::RestoreFrames(Js::FunctionBody* functionBody, InlinedFrameLayout* outerMostFrame, Js::JavascriptCallStackLayout* callstack)
+void InlineeFrameRecord::RestoreFrames(Js::FunctionBody* functionBody, InlinedFrameLayout* outerMostFrame, Js::JavascriptCallStackLayout* callstack, bool deepCopy)
 {
     InlineeFrameRecord* innerMostRecord = this;
     class AutoReverse
@@ -271,7 +274,7 @@ void InlineeFrameRecord::RestoreFrames(Js::FunctionBody* functionBody, InlinedFr
 
     while (currentRecord)
     {
-        currentRecord->Restore(functionBody, currentFrame, callstack);
+        currentRecord->Restore(functionBody, currentFrame, callstack, deepCopy);
         currentRecord = currentRecord->parent;
         currentFrame = currentFrame->Next();
     }
@@ -280,7 +283,7 @@ void InlineeFrameRecord::RestoreFrames(Js::FunctionBody* functionBody, InlinedFr
     currentFrame->callInfo.Count = 0;
 }
 
-Js::Var InlineeFrameRecord::Restore(int offset, bool isFloat64, bool isInt32, Js::JavascriptCallStackLayout * layout, Js::FunctionBody* functionBody) const
+Js::Var InlineeFrameRecord::Restore(int offset, bool isFloat64, bool isInt32, Js::JavascriptCallStackLayout * layout, Js::FunctionBody* functionBody, bool deepCopy) const
 {
     Js::Var value;
     bool boxStackInstance = true;
@@ -322,7 +325,7 @@ Js::Var InlineeFrameRecord::Restore(int offset, bool isFloat64, bool isInt32, Js
         if (boxStackInstance)
         {
             Js::Var oldValue = value;
-            value = Js::JavascriptOperators::BoxStackInstance(oldValue, functionBody->GetScriptContext(), /* allowStackFunction */ true);
+            value = Js::JavascriptOperators::BoxStackInstance(oldValue, functionBody->GetScriptContext(), /* allowStackFunction */ true, deepCopy);
 
 #if ENABLE_DEBUG_CONFIG_OPTIONS
             if (oldValue != value)

diff --git a/lib/Backend/InlineeFrameInfo.h b/lib/Backend/InlineeFrameInfo.h
@@ -108,7 +108,7 @@ struct InlineeFrameRecord
     }
 
     void PopulateParent(Func* func);
-    void RestoreFrames(Js::FunctionBody* functionBody, InlinedFrameLayout* outerMostInlinee, Js::JavascriptCallStackLayout* callstack);
+    void RestoreFrames(Js::FunctionBody* functionBody, InlinedFrameLayout* outerMostInlinee, Js::JavascriptCallStackLayout* callstack, bool deepCopy);
     void Finalize(Func* inlinee, uint currentOffset);
 #if DBG_DUMP
     void Dump() const;
@@ -123,8 +123,8 @@ struct InlineeFrameRecord
     }
 
 private:
-    void Restore(Js::FunctionBody* functionBody, InlinedFrameLayout *outerMostFrame, Js::JavascriptCallStackLayout * layout) const;
-    Js::Var Restore(int offset, bool isFloat64, bool isInt32, Js::JavascriptCallStackLayout * layout, Js::FunctionBody* functionBody) const;
+    void Restore(Js::FunctionBody* functionBody, InlinedFrameLayout *outerMostFrame, Js::JavascriptCallStackLayout * layout, bool deepCopy) const;
+    Js::Var Restore(int offset, bool isFloat64, bool isInt32, Js::JavascriptCallStackLayout * layout, Js::FunctionBody* functionBody, bool deepCopy) const;
     InlineeFrameRecord* Reverse();
 };
 

diff --git a/lib/Backend/JITThunkEmitter.cpp b/lib/Backend/JITThunkEmitter.cpp
@@ -77,7 +77,7 @@ JITThunkEmitter<TAlloc>::CreateThunk(uintptr_t entryPoint)
 
     if (IsThunkPageEmpty(pageStartAddress))
     {
-        if (this->codeAllocator->Alloc((PVOID)pageStartAddress, AutoSystemInfo::PageSize, MEM_COMMIT, PAGE_EXECUTE, true) == nullptr)
+        if (this->codeAllocator->AllocPages((PVOID)pageStartAddress, 1, MEM_COMMIT, PAGE_EXECUTE, true) == nullptr)
         {
             this->codeAllocator->FreeLocal(localPageAddress);
             return NULL;
@@ -165,7 +165,7 @@ JITThunkEmitter<TAlloc>::EnsureInitialized()
         // check again because we did the first one outside of lock
         if (this->baseAddress == NULL)
         {
-            this->baseAddress = (uintptr_t)this->codeAllocator->Alloc(nullptr, TotalThunkSize, MEM_RESERVE, PAGE_EXECUTE, true);
+            this->baseAddress = (uintptr_t)this->codeAllocator->AllocPages(nullptr, PageCount, MEM_RESERVE, PAGE_EXECUTE, true);
         }
     }
     return this->baseAddress;

diff --git a/lib/Backend/Lower.cpp b/lib/Backend/Lower.cpp
@@ -8330,7 +8330,7 @@ Lowerer::LowerAddLeftDeadForString(IR::Instr *instr)
     InsertCompareBranch(
         regLeftCharLengthOpnd,
         IR::IntConstOpnd::New(Js::JavascriptString::MaxCharLength, TyUint32, m_func),
-        Js::OpCode::BrGt_A,
+        Js::OpCode::BrGe_A,
         labelHelper,
         insertBeforeInstr);
 
@@ -14702,6 +14702,29 @@ IR::BranchInstr *Lowerer::InsertTestBranch(
     return InsertBranch(branchOpCode, isUnsigned, target, insertBeforeInstr);
 }
 
+/* Inserts add with an overflow check, if we overflow throw OOM
+ * add dst, src
+ * jno $continueLabel
+ * overflow code
+ * $continueLabel : fall through
+*/
+void Lowerer::InsertAddWithOverflowCheck(
+    const bool needFlags,
+    IR::Opnd *const dst,
+    IR::Opnd *src1,
+    IR::Opnd *src2,
+    IR::Instr *const insertBeforeInstr,
+    IR::Instr **const onOverflowInsertBeforeInstrRef)
+{
+    Func * func = insertBeforeInstr->m_func;
+    InsertAdd(needFlags, dst, src1, src2, insertBeforeInstr);
+
+    IR::LabelInstr *const continueLabel = IR::LabelInstr::New(Js::OpCode::Label, func, false);
+    InsertBranch(LowererMD::MDNotOverflowBranchOpcode, continueLabel, insertBeforeInstr);
+
+    *onOverflowInsertBeforeInstrRef = continueLabel;
+}
+
 IR::Instr *Lowerer::InsertAdd(
     const bool needFlags,
     IR::Opnd *const dst,
@@ -23210,7 +23233,15 @@ Lowerer::LowerSetConcatStrMultiItem(IR::Instr * instr)
         srcLength = IR::RegOpnd::New(TyUint32, func);
         InsertMove(srcLength, IR::IndirOpnd::New(srcOpnd, Js::ConcatStringMulti::GetOffsetOfcharLength(), TyUint32, func), instr);
     }
-    InsertAdd(false, dstLength, dstLength, srcLength, instr);
+
+    IR::Instr *onOverflowInsertBeforeInstr;
+    InsertAddWithOverflowCheck(false, dstLength, dstLength, srcLength, instr, &onOverflowInsertBeforeInstr);
+    IR::Instr* callInstr = IR::Instr::New(Js::OpCode::Call, func);
+    callInstr->SetSrc1(IR::HelperCallOpnd::New(IR::HelperOp_OutOfMemoryError, func));
+
+    instr->InsertBefore(onOverflowInsertBeforeInstr);
+    onOverflowInsertBeforeInstr->InsertBefore(callInstr);
+    this->m_lowererMD.LowerCall(callInstr, 0);
 
     dstOpnd->SetOffset(dstOpnd->GetOffset() * sizeof(Js::JavascriptString *) + Js::ConcatStringMulti::GetOffsetOfSlots());
 

diff --git a/lib/Backend/Lower.h b/lib/Backend/Lower.h
@@ -359,6 +359,8 @@ class Lowerer
 
 public:
     static void InsertDecUInt32PreventOverflow(IR::Opnd *const dst, IR::Opnd *const src, IR::Instr *const insertBeforeInstr, IR::Instr * *const onOverflowInsertBeforeInstrRef = nullptr);
+    static void InsertAddWithOverflowCheck(const bool needFlags, IR::Opnd *const dst, IR::Opnd *src1, IR::Opnd *src2, IR::Instr *const insertBeforeInstr, IR::Instr **const onOverflowInsertBeforeInstrRef);
+
     void InsertFloatCheckForZeroOrNanBranch(IR::Opnd *const src, const bool branchOnZeroOrNan, IR::LabelInstr *const target, IR::LabelInstr *const fallthroughLabel, IR::Instr *const insertBeforeInstr);
 
 public:

diff --git a/lib/Common/ChakraCoreVersion.h b/lib/Common/ChakraCoreVersion.h
@@ -17,7 +17,7 @@
 // ChakraCore version number definitions (used in ChakraCore binary metadata)
 #define CHAKRA_CORE_MAJOR_VERSION 1
 #define CHAKRA_CORE_MINOR_VERSION 7
-#define CHAKRA_CORE_PATCH_VERSION 5
+#define CHAKRA_CORE_PATCH_VERSION 6
 #define CHAKRA_CORE_VERSION_RELEASE_QFE 0 // Redundant with PATCH_VERSION. Keep this value set to 0.
 
 // -------------

diff --git a/lib/Common/ConfigFlagsList.h b/lib/Common/ConfigFlagsList.h
@@ -601,7 +601,7 @@ PHASE(All)
 #define DEFAULT_CONFIG_ES7ValuesEntries        (true)
 #define DEFAULT_CONFIG_ESObjectGetOwnPropertyDescriptors (true)
 
-#define DEFAULT_CONFIG_ESSharedArrayBuffer     (true)
+#define DEFAULT_CONFIG_ESSharedArrayBuffer     (false)
 
 #define DEFAULT_CONFIG_ES6Verbose              (false)
 #define DEFAULT_CONFIG_ES6All                  (false)
@@ -611,6 +611,7 @@ PHASE(All)
 #define DEFAULT_CONFIG_TraceAsyncDebugCalls     (false)
 #define DEFAULT_CONFIG_ForcePostLowerGlobOptInstrString (false)
 #define DEFAULT_CONFIG_EnumerateSpecialPropertiesInDebugger (true)
+#define DEFAULT_CONFIG_ESDynamicImport         (false)
 #endif
 
 #define DEFAULT_CONFIG_MaxJITFunctionBytecodeByteLength (4800000)
@@ -1029,6 +1030,11 @@ FLAGPR           (Boolean, ES6, ES7TrailingComma       , "Enable ES7 trailing co
 FLAGPR           (Boolean, ES6, ES6IsConcatSpreadable  , "Enable ES6 isConcatSpreadable Symbol"                     , DEFAULT_CONFIG_ES6IsConcatSpreadable)
 FLAGPR           (Boolean, ES6, ES6Math                , "Enable ES6 Math extensions"                               , DEFAULT_CONFIG_ES6Math)
 
+#ifndef COMPILE_DISABLE_ESDynamicImport
+#define COMPILE_DISABLE_ESDynamicImport 0
+#endif
+FLAGPR_REGOVR_EXP(Boolean, ES6, ESDynamicImport        , "Enable dynamic import"                                    , DEFAULT_CONFIG_ESDynamicImport)
+
 FLAGPR           (Boolean, ES6, ES6Module              , "Enable ES6 Modules"                                       , DEFAULT_CONFIG_ES6Module)
 FLAGPR           (Boolean, ES6, ES6Object              , "Enable ES6 Object extensions"                             , DEFAULT_CONFIG_ES6Object)
 FLAGPR           (Boolean, ES6, ES6Number              , "Enable ES6 Number extensions"                             , DEFAULT_CONFIG_ES6Number)
@@ -1078,7 +1084,7 @@ FLAGPR           (Boolean, ES6, ESObjectGetOwnPropertyDescriptors, "Enable Objec
 #ifndef COMPILE_DISABLE_ESSharedArrayBuffer
     #define COMPILE_DISABLE_ESSharedArrayBuffer 0
 #endif
-FLAGPRA          (Boolean, ES6, ESSharedArrayBuffer    , sab     , "Enable SharedArrayBuffer"                       , DEFAULT_CONFIG_ESSharedArrayBuffer)
+FLAGPR_REGOVR_EXP(Boolean, ES6, ESSharedArrayBuffer    , "Enable SharedArrayBuffer"                                 , DEFAULT_CONFIG_ESSharedArrayBuffer)
 
 // /ES6 (BLUE+1) features/flags
 

diff --git a/lib/Common/Core/SysInfo.h b/lib/Common/Core/SysInfo.h
@@ -64,6 +64,8 @@ class AutoSystemInfo : public SYSTEM_INFO
 #endif
     static DWORD const PageSize = 4096;
 
+    static size_t const MaxPageCount = SIZE_MAX / PageSize;
+
 #ifdef STACK_ALIGN
     static DWORD const StackAlign = STACK_ALIGN;
 #else