C++ Optional类代码示例

void UninitializedObjectChecker::checkEndFunction(
    const ReturnStmt *RS, CheckerContext &Context) const {

  const auto *CtorDecl = dyn_cast_or_null<CXXConstructorDecl>(
      Context.getLocationContext()->getDecl());
  if (!CtorDecl)
    return;

  if (!CtorDecl->isUserProvided())
    return;

  if (CtorDecl->getParent()->isUnion())
    return;

  // This avoids essentially the same error being reported multiple times.
  if (willObjectBeAnalyzedLater(CtorDecl, Context))
    return;

  Optional<nonloc::LazyCompoundVal> Object = getObjectVal(CtorDecl, Context);
  if (!Object)
    return;

  FindUninitializedFields F(Context.getState(), Object->getRegion(),
                            CheckPointeeInitialization);

  const UninitFieldMap &UninitFields = F.getUninitFields();

  if (UninitFields.empty())
    return;

  // In non-pedantic mode, if Object's region doesn't contain a single
  // initialized field, we'll assume that Object was intentionally left
  // uninitialized.
  if (!IsPedantic && !F.isAnyFieldInitialized())
    return;

  // There are uninitialized fields in the record.

  ExplodedNode *Node = Context.generateNonFatalErrorNode(Context.getState());
  if (!Node)
    return;

  PathDiagnosticLocation LocUsedForUniqueing;
  const Stmt *CallSite = Context.getStackFrame()->getCallSite();
  if (CallSite)
    LocUsedForUniqueing = PathDiagnosticLocation::createBegin(
        CallSite, Context.getSourceManager(), Node->getLocationContext());

  // For Plist consumers that don't support notes just yet, we'll convert notes
  // to warnings.
  if (ShouldConvertNotesToWarnings) {
    for (const auto &Pair : UninitFields) {

      auto Report = llvm::make_unique<BugReport>(
          *BT_uninitField, Pair.second, Node, LocUsedForUniqueing,
          Node->getLocationContext()->getDecl());
      Context.emitReport(std::move(Report));
    }
    return;
  }

  SmallString<100> WarningBuf;
  llvm::raw_svector_ostream WarningOS(WarningBuf);
  WarningOS << UninitFields.size() << " uninitialized field"
            << (UninitFields.size() == 1 ? "" : "s")
            << " at the end of the constructor call";

  auto Report = llvm::make_unique<BugReport>(
      *BT_uninitField, WarningOS.str(), Node, LocUsedForUniqueing,
      Node->getLocationContext()->getDecl());

  for (const auto &Pair : UninitFields) {
    Report->addNote(Pair.second,
                    PathDiagnosticLocation::create(Pair.first->getDecl(),
                                                   Context.getSourceManager()));
  }
  Context.emitReport(std::move(Report));
}

PaintLayerPainter::PaintResult PaintLayerPainter::paintLayerContentsInternal(GraphicsContext* context, const PaintLayerPaintingInfo& paintingInfoArg, PaintLayerFlags paintFlags, FragmentPolicy fragmentPolicy)
{
    ASSERT(m_paintLayer.isSelfPaintingLayer() || m_paintLayer.hasSelfPaintingLayerDescendant());
    ASSERT(!(paintFlags & PaintLayerAppliedTransform));

    bool isSelfPaintingLayer = m_paintLayer.isSelfPaintingLayer();
    bool isPaintingOverlayScrollbars = paintFlags & PaintLayerPaintingOverlayScrollbars;
    bool isPaintingScrollingContent = paintFlags & PaintLayerPaintingCompositingScrollingPhase;
    bool isPaintingCompositedForeground = paintFlags & PaintLayerPaintingCompositingForegroundPhase;
    bool isPaintingCompositedBackground = paintFlags & PaintLayerPaintingCompositingBackgroundPhase;
    bool isPaintingOverflowContents = paintFlags & PaintLayerPaintingOverflowContents;
    // Outline always needs to be painted even if we have no visible content. Also,
    // the outline is painted in the background phase during composited scrolling.
    // If it were painted in the foreground phase, it would move with the scrolled
    // content. When not composited scrolling, the outline is painted in the
    // foreground phase. Since scrolled contents are moved by paint invalidation in this
    // case, the outline won't get 'dragged along'.
    bool shouldPaintOutline = isSelfPaintingLayer && !isPaintingOverlayScrollbars
        && ((isPaintingScrollingContent && isPaintingCompositedBackground)
        || (!isPaintingScrollingContent && isPaintingCompositedForeground));
    bool shouldPaintContent = m_paintLayer.hasVisibleContent() && isSelfPaintingLayer && !isPaintingOverlayScrollbars;

    PaintResult result = FullyPainted;

    if (paintFlags & PaintLayerPaintingRootBackgroundOnly && !m_paintLayer.layoutObject()->isLayoutView() && !m_paintLayer.layoutObject()->isDocumentElement())
        return result;

    PaintLayerPaintingInfo paintingInfo = paintingInfoArg;

    // Ensure our lists are up-to-date.
    m_paintLayer.stackingNode()->updateLayerListsIfNeeded();

    LayoutPoint offsetFromRoot;
    m_paintLayer.convertToLayerCoords(paintingInfo.rootLayer, offsetFromRoot);

    if (m_paintLayer.compositingState() == PaintsIntoOwnBacking)
        offsetFromRoot.move(m_paintLayer.subpixelAccumulation());
    else
        offsetFromRoot.move(paintingInfo.subPixelAccumulation);

    LayoutRect bounds = m_paintLayer.physicalBoundingBox(offsetFromRoot);
    if (!paintingInfo.paintDirtyRect.contains(bounds))
        result = MaybeNotFullyPainted;

    LayoutRect rootRelativeBounds;
    bool rootRelativeBoundsComputed = false;

    if (paintingInfo.ancestorHasClipPathClipping && m_paintLayer.layoutObject()->style()->position() != StaticPosition)
        UseCounter::count(m_paintLayer.layoutObject()->document(), UseCounter::ClipPathOfPositionedElement);

    // These helpers output clip and compositing operations using a RAII pattern. Stack-allocated-varibles are destructed in the reverse order of construction,
    // so they are nested properly.
    ClipPathHelper clipPathHelper(context, m_paintLayer, paintingInfo, rootRelativeBounds, rootRelativeBoundsComputed, offsetFromRoot, paintFlags);

    Optional<CompositingRecorder> compositingRecorder;
    // Blending operations must be performed only with the nearest ancestor stacking context.
    // Note that there is no need to composite if we're painting the root.
    // FIXME: this should be unified further into PaintLayer::paintsWithTransparency().
    bool shouldCompositeForBlendMode = (!m_paintLayer.layoutObject()->isDocumentElement() || m_paintLayer.layoutObject()->isSVGRoot()) && m_paintLayer.stackingNode()->isStackingContext() && m_paintLayer.hasNonIsolatedDescendantWithBlendMode();
    if (shouldCompositeForBlendMode || m_paintLayer.paintsWithTransparency(paintingInfo.globalPaintFlags())) {
        FloatRect compositingBounds = FloatRect(m_paintLayer.paintingExtent(paintingInfo.rootLayer, paintingInfo.subPixelAccumulation, paintingInfo.globalPaintFlags()));
        compositingRecorder.emplace(*context, *m_paintLayer.layoutObject(),
            WebCoreCompositeToSkiaComposite(CompositeSourceOver, m_paintLayer.layoutObject()->style()->blendMode()),
            m_paintLayer.layoutObject()->opacity(), &compositingBounds);
    }

    PaintLayerPaintingInfo localPaintingInfo(paintingInfo);
    if (m_paintLayer.compositingState() == PaintsIntoOwnBacking)
        localPaintingInfo.subPixelAccumulation = m_paintLayer.subpixelAccumulation();

    PaintLayerFragments layerFragments;
    if (shouldPaintContent || shouldPaintOutline || isPaintingOverlayScrollbars) {
        // Collect the fragments. This will compute the clip rectangles and paint offsets for each layer fragment.
        ClipRectsCacheSlot cacheSlot = (paintFlags & PaintLayerUncachedClipRects) ? UncachedClipRects : PaintingClipRects;
        ShouldRespectOverflowClip respectOverflowClip = shouldRespectOverflowClip(paintFlags, m_paintLayer.layoutObject());
        if (fragmentPolicy == ForceSingleFragment)
            m_paintLayer.appendSingleFragmentIgnoringPagination(layerFragments, localPaintingInfo.rootLayer, localPaintingInfo.paintDirtyRect, cacheSlot, IgnoreOverlayScrollbarSize, respectOverflowClip, &offsetFromRoot, localPaintingInfo.subPixelAccumulation);
        else
            m_paintLayer.collectFragments(layerFragments, localPaintingInfo.rootLayer, localPaintingInfo.paintDirtyRect, cacheSlot, IgnoreOverlayScrollbarSize, respectOverflowClip, &offsetFromRoot, localPaintingInfo.subPixelAccumulation);
        if (shouldPaintContent) {
            // TODO(wangxianzhu): This is for old slow scrolling. Implement similar optimization for slimming paint v2.
            shouldPaintContent = atLeastOneFragmentIntersectsDamageRect(layerFragments, localPaintingInfo, paintFlags, offsetFromRoot);
            if (!shouldPaintContent)
                result = MaybeNotFullyPainted;
        }
    }

    bool selectionOnly = localPaintingInfo.globalPaintFlags() & GlobalPaintSelectionOnly;
    // If this layer's layoutObject is a child of the paintingRoot, we paint unconditionally, which
    // is done by passing a nil paintingRoot down to our layoutObject (as if no paintingRoot was ever set).
    // Else, our layout tree may or may not contain the painting root, so we pass that root along
    // so it will be tested against as we descend through the layoutObjects.
    LayoutObject* paintingRootForLayoutObject = 0;
    if (localPaintingInfo.paintingRoot && !m_paintLayer.layoutObject()->isDescendantOf(localPaintingInfo.paintingRoot))
        paintingRootForLayoutObject = localPaintingInfo.paintingRoot;

    { // Begin block for the lifetime of any filter.
        FilterPainter filterPainter(m_paintLayer, context, offsetFromRoot, layerFragments.isEmpty() ? ClipRect() : layerFragments[0].backgroundRect, localPaintingInfo, paintFlags,
            rootRelativeBounds, rootRelativeBoundsComputed);

//.........这里部分代码省略.........

PaintLayerPainter::PaintResult PaintLayerPainter::paintChildren(unsigned childrenToVisit, GraphicsContext* context, const PaintLayerPaintingInfo& paintingInfo, PaintLayerFlags paintFlags)
{
    PaintResult result = FullyPainted;
    if (!m_paintLayer.hasSelfPaintingLayerDescendant())
        return result;

#if ENABLE(ASSERT)
    LayerListMutationDetector mutationChecker(m_paintLayer.stackingNode());
#endif

    PaintLayerStackingNodeIterator iterator(*m_paintLayer.stackingNode(), childrenToVisit);
    PaintLayerStackingNode* child = iterator.next();
    if (!child)
        return result;

    DisplayItem::Type subsequenceType;
    if (childrenToVisit == NegativeZOrderChildren) {
        subsequenceType = DisplayItem::SubsequenceNegativeZOrder;
    } else {
        ASSERT(childrenToVisit == (NormalFlowChildren | PositiveZOrderChildren));
        subsequenceType = DisplayItem::SubsequenceNormalFlowAndPositiveZOrder;
    }

    Optional<SubsequenceRecorder> subsequenceRecorder;
    if (!paintingInfo.disableSubsequenceCache
        && !(paintingInfo.globalPaintFlags() & GlobalPaintFlattenCompositingLayers)
        && !(paintFlags & PaintLayerPaintingReflection)
        && !(paintFlags & PaintLayerPaintingRootBackgroundOnly)) {
        if (!m_paintLayer.needsRepaint()
            && paintingInfo.scrollOffsetAccumulation == m_paintLayer.previousScrollOffsetAccumulationForPainting()
            && SubsequenceRecorder::useCachedSubsequenceIfPossible(*context, m_paintLayer, subsequenceType))
            return result;
        subsequenceRecorder.emplace(*context, m_paintLayer, subsequenceType);
    }

    IntSize scrollOffsetAccumulationForChildren = paintingInfo.scrollOffsetAccumulation;
    if (m_paintLayer.layoutObject()->hasOverflowClip())
        scrollOffsetAccumulationForChildren += m_paintLayer.layoutBox()->scrolledContentOffset();

    bool disableChildSubsequenceCache = !RuntimeEnabledFeatures::slimmingPaintV2Enabled()
        && (m_paintLayer.layoutObject()->hasOverflowClip() || m_paintLayer.layoutObject()->hasClip());

    for (; child; child = iterator.next()) {
        PaintLayerPainter childPainter(*child->layer());
        // If this Layer should paint into its own backing or a grouped backing, that will be done via CompositedLayerMapping::paintContents()
        // and CompositedLayerMapping::doPaintTask().
        if (!childPainter.shouldPaintLayerInSoftwareMode(paintingInfo.globalPaintFlags(), paintFlags))
            continue;

        PaintLayerPaintingInfo childPaintingInfo = paintingInfo;
        childPaintingInfo.disableSubsequenceCache = disableChildSubsequenceCache;
        childPaintingInfo.scrollOffsetAccumulation = scrollOffsetAccumulationForChildren;
        // Rare case: accumulate scroll offset of non-stacking-context ancestors up to m_paintLayer.
        for (PaintLayer* parentLayer = child->layer()->parent(); parentLayer != &m_paintLayer; parentLayer = parentLayer->parent()) {
            if (parentLayer->layoutObject()->hasOverflowClip())
                childPaintingInfo.scrollOffsetAccumulation += parentLayer->layoutBox()->scrolledContentOffset();
        }

        if (childPainter.paintLayer(context, childPaintingInfo, paintFlags) == MaybeNotFullyPainted)
            result = MaybeNotFullyPainted;
    }

    // Set subsequence not cacheable if the bounding box of this layer and descendants is not fully contained
    // by paintRect, because later paintRect changes may expose new contents which will need repainting.
    if (result == MaybeNotFullyPainted && subsequenceRecorder)
        subsequenceRecorder->setUncacheable();

    return result;
}

static ReductionKind
matchVectorSplittingReduction(const ExtractElementInst *ReduxRoot,
                              unsigned &Opcode, Type *&Ty) {
  if (!EnableReduxCost)
    return RK_None;

  // Need to extract the first element.
  ConstantInt *CI = dyn_cast<ConstantInt>(ReduxRoot->getOperand(1));
  unsigned Idx = ~0u;
  if (CI)
    Idx = CI->getZExtValue();
  if (Idx != 0)
    return RK_None;

  auto *RdxStart = dyn_cast<Instruction>(ReduxRoot->getOperand(0));
  if (!RdxStart)
    return RK_None;
  Optional<ReductionData> RD = getReductionData(RdxStart);
  if (!RD)
    return RK_None;

  Type *VecTy = ReduxRoot->getOperand(0)->getType();
  unsigned NumVecElems = VecTy->getVectorNumElements();
  if (!isPowerOf2_32(NumVecElems))
    return RK_None;

  // We look for a sequence of shuffles and adds like the following matching one
  // fadd, shuffle vector pair at a time.
  //  
  // %rdx.shuf = shufflevector <4 x float> %rdx, <4 x float> undef,
  //                           <4 x i32> <i32 2, i32 3, i32 undef, i32 undef>
  // %bin.rdx = fadd <4 x float> %rdx, %rdx.shuf
  // %rdx.shuf7 = shufflevector <4 x float> %bin.rdx, <4 x float> undef,
  //                          <4 x i32> <i32 1, i32 undef, i32 undef, i32 undef>
  // %bin.rdx8 = fadd <4 x float> %bin.rdx, %rdx.shuf7
  // %r = extractelement <4 x float> %bin.rdx8, i32 0

  unsigned MaskStart = 1;
  Instruction *RdxOp = RdxStart;
  SmallVector<int, 32> ShuffleMask(NumVecElems, 0); 
  unsigned NumVecElemsRemain = NumVecElems;
  while (NumVecElemsRemain - 1) {
    // Check for the right reduction operation.
    if (!RdxOp)
      return RK_None;
    Optional<ReductionData> RDLevel = getReductionData(RdxOp);
    if (!RDLevel || !RDLevel->hasSameData(*RD))
      return RK_None;

    Value *NextRdxOp;
    ShuffleVectorInst *Shuffle;
    std::tie(NextRdxOp, Shuffle) =
        getShuffleAndOtherOprd(RDLevel->LHS, RDLevel->RHS);

    // Check the current reduction operation and the shuffle use the same value.
    if (Shuffle == nullptr)
      return RK_None;
    if (Shuffle->getOperand(0) != NextRdxOp)
      return RK_None;

    // Check that shuffle masks matches.
    for (unsigned j = 0; j != MaskStart; ++j)
      ShuffleMask[j] = MaskStart + j;
    // Fill the rest of the mask with -1 for undef.
    std::fill(&ShuffleMask[MaskStart], ShuffleMask.end(), -1);

    SmallVector<int, 16> Mask = Shuffle->getShuffleMask();
    if (ShuffleMask != Mask)
      return RK_None;

    RdxOp = dyn_cast<Instruction>(NextRdxOp);
    NumVecElemsRemain /= 2;
    MaskStart *= 2;
  }

  Opcode = RD->Opcode;
  Ty = VecTy;
  return RD->Kind;
}

 static void TestDict(DictPtr dict) {
   Optional<DictEntry> entry;
   entry = dict->MatchPrefix("BYVoid");
   AssertTrue(!entry.IsNull());
   AssertEquals("BYVoid", entry.Get().key);
   AssertEquals("byv", entry.Get().GetDefault());
   
   entry = dict->MatchPrefix("BYVoid123");
   AssertTrue(!entry.IsNull());
   AssertEquals("BYVoid", entry.Get().key);
   AssertEquals("byv", entry.Get().GetDefault());
   
   entry = dict->MatchPrefix(utf8("積羽沉舟"));
   AssertTrue(!entry.IsNull());
   AssertEquals(utf8("積羽沉舟"), entry.Get().key);
   AssertEquals(utf8("羣輕折軸"), entry.Get().GetDefault());
   
   entry = dict->MatchPrefix("Unknown");
   AssertTrue(entry.IsNull());
   
   const vector<DictEntry> matches = dict->MatchAllPrefixes(utf8("清華大學計算機系"));
   AssertEquals(3, matches.size());
   AssertEquals(utf8("清華大學"), matches.at(0).key);
   AssertEquals("TsinghuaUniversity", matches.at(0).GetDefault());
   AssertEquals(utf8("清華"), matches.at(1).key);
   AssertEquals("Tsinghua", matches.at(1).GetDefault());
   AssertEquals(utf8("清"), matches.at(2).key);
   AssertEquals("Tsing", matches.at(2).GetDefault());
 }

/// Try to classify the dynamic-cast relationship between two types.
DynamicCastFeasibility
swift::classifyDynamicCast(Module *M,
                           CanType source,
                           CanType target,
                           bool isSourceTypeExact,
                           bool isWholeModuleOpts) {
  if (source == target) return DynamicCastFeasibility::WillSucceed;

  auto sourceObject = source.getAnyOptionalObjectType();
  auto targetObject = target.getAnyOptionalObjectType();

  // A common level of optionality doesn't affect the feasibility.
  if (sourceObject && targetObject) {
    return classifyDynamicCast(M, sourceObject, targetObject);

  // Nor does casting to a more optional type.
  } else if (targetObject) {
    return classifyDynamicCast(M, source, targetObject,
                               /* isSourceTypeExact */ false,
                               isWholeModuleOpts);

  // Casting to a less-optional type can always fail.
  } else if (sourceObject) {
    return weakenSuccess(classifyDynamicCast(M, sourceObject, target,
                                             /* isSourceTypeExact */ false,
                                             isWholeModuleOpts));
  }
  assert(!sourceObject && !targetObject);

  // Assume that casts to or from existential types or involving
  // dependent types can always succeed.  This is over-conservative.
  if (source->hasArchetype() || source.isExistentialType() ||
      target->hasArchetype() || target.isExistentialType()) {

    auto *SourceNominalTy = source.getAnyNominal();

    // Check conversions from non-protocol types into protocol types.
    if (!source.isExistentialType() &&
        SourceNominalTy &&
        target.isExistentialType())
      return classifyDynamicCastToProtocol(source, target, isWholeModuleOpts);

    // Casts from class existential into a non-class can never succeed.
    if (source->isClassExistentialType() &&
        !target.isAnyExistentialType() &&
        !target.getClassOrBoundGenericClass() &&
        !isa<ArchetypeType>(target) &&
        !mayBridgeToObjectiveC(M, target)) {
      assert((target.getEnumOrBoundGenericEnum() ||
              target.getStructOrBoundGenericStruct() ||
              isa<TupleType>(target) ||
              isa<SILFunctionType>(target) ||
              isa<FunctionType>(target) ||
              isa<MetatypeType>(target)) &&
             "Target should be an enum, struct, tuple, metatype or function type");
      return DynamicCastFeasibility::WillFail;
    }

    return DynamicCastFeasibility::MaySucceed;
  }

  // Metatype casts.
  if (auto sourceMetatype = dyn_cast<AnyMetatypeType>(source)) {
    auto targetMetatype = dyn_cast<AnyMetatypeType>(target);
    if (!targetMetatype) return DynamicCastFeasibility::WillFail;

    source = sourceMetatype.getInstanceType();
    target = targetMetatype.getInstanceType();

    if (source == target &&
        targetMetatype.isAnyExistentialType() ==
            sourceMetatype.isAnyExistentialType())
      return DynamicCastFeasibility::WillSucceed;

    if (targetMetatype.isAnyExistentialType() &&
        (isa<ProtocolType>(target) || isa<ProtocolCompositionType>(target))) {
      auto Feasibility = classifyDynamicCastToProtocol(source,
                                                       target,
                                                       isWholeModuleOpts);
      // Cast from existential metatype to existential metatype may still
      // succeed, even if we cannot prove anything statically.
      if (Feasibility != DynamicCastFeasibility::WillFail ||
          !sourceMetatype.isAnyExistentialType())
        return Feasibility;
    }

    // If isSourceTypeExact is true, we know we are casting the result of a
    // MetatypeInst instruction.
    if (isSourceTypeExact) {
      // If source or target are existentials, then it can be cast
      // successfully only into itself.
      if ((target.isAnyExistentialType() || source.isAnyExistentialType()) &&
          target != source)
        return DynamicCastFeasibility::WillFail;
    }

    // Casts from class existential metatype into a concrete non-class metatype
    // can never succeed.
    if (source->isClassExistentialType() &&
//.........这里部分代码省略.........

static Reloc::Model getEffectiveRelocModel(CodeModel::Model CM,
                                           Optional<Reloc::Model> RM) {
  if (!RM.hasValue() || CM == CodeModel::JITDefault)
    return Reloc::Static;
  return *RM;
}

static Reloc::Model getEffectiveRelocModel(Optional<Reloc::Model> RM) {
  if (!RM.hasValue())
    return Reloc::Static;
  return *RM;
}

void
HTMLCanvasElement::ToBlob(JSContext* aCx,
                          FileCallback& aCallback,
                          const nsAString& aType,
                          const Optional<JS::Handle<JS::Value> >& aParams,
                          ErrorResult& aRv)
{
  // do a trust check if this is a write-only canvas
  if (mWriteOnly && !nsContentUtils::IsCallerChrome()) {
    aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
    return;
  }

  nsAutoString type;
  aRv = nsContentUtils::ASCIIToLower(aType, type);
  if (aRv.Failed()) {
    return;
  }

  JS::Value encoderOptions = aParams.WasPassed()
                             ? aParams.Value()
                             : JS::UndefinedValue();

  nsAutoString params;
  bool usingCustomParseOptions;
  aRv = ParseParams(aCx, type, encoderOptions, params, &usingCustomParseOptions);
  if (aRv.Failed()) {
    return;
  }

#ifdef DEBUG
  if (mCurrentContext) {
    // We disallow canvases of width or height zero, and set them to 1, so
    // we will have a discrepancy with the sizes of the canvas and the context.
    // That discrepancy is OK, the rest are not.
    nsIntSize elementSize = GetWidthHeight();
    MOZ_ASSERT(elementSize.width == mCurrentContext->GetWidth() ||
               (elementSize.width == 0 && mCurrentContext->GetWidth() == 1));
    MOZ_ASSERT(elementSize.height == mCurrentContext->GetHeight() ||
               (elementSize.height == 0 && mCurrentContext->GetHeight() == 1));
  }
#endif

  nsCOMPtr<nsIScriptContext> scriptContext =
    GetScriptContextFromJSContext(nsContentUtils::GetCurrentJSContext());

  uint8_t* imageBuffer = nullptr;
  int32_t format = 0;
  if (mCurrentContext) {
    mCurrentContext->GetImageBuffer(&imageBuffer, &format);
  }

  aRv = ImageEncoder::ExtractDataAsync(type,
                                       params,
                                       usingCustomParseOptions,
                                       imageBuffer,
                                       format,
                                       GetSize(),
                                       mCurrentContext,
                                       scriptContext,
                                       aCallback);
}

void NameBinder::addImport(
    SmallVectorImpl<std::pair<ImportedModule, ImportOptions>> &imports,
    ImportDecl *ID) {
  if (ID->getModulePath().front().first == SF.getParentModule()->getName() &&
      ID->getModulePath().size() == 1 && !shouldImportSelfImportClang(ID, SF)) {
    // If the imported module name is the same as the current module,
    // produce a diagnostic.
    StringRef filename = llvm::sys::path::filename(SF.getFilename());
    if (filename.empty())
      Context.Diags.diagnose(ID, diag::sema_import_current_module,
                             ID->getModulePath().front().first);
    else
      Context.Diags.diagnose(ID, diag::sema_import_current_module_with_file,
                             filename, ID->getModulePath().front().first);
    ID->setModule(SF.getParentModule());
    return;
  }

  Module *M = getModule(ID->getModulePath());
  if (!M) {
    SmallString<64> modulePathStr;
    interleave(ID->getModulePath(),
               [&](ImportDecl::AccessPathElement elem) {
                 modulePathStr += elem.first.str();
               },
               [&] { modulePathStr += "."; });

    auto diagKind = diag::sema_no_import;
    if (SF.Kind == SourceFileKind::REPL || Context.LangOpts.DebuggerSupport)
      diagKind = diag::sema_no_import_repl;
    diagnose(ID->getLoc(), diagKind, modulePathStr);

    if (Context.SearchPathOpts.SDKPath.empty() &&
        llvm::Triple(llvm::sys::getProcessTriple()).isMacOSX()) {
      diagnose(SourceLoc(), diag::sema_no_import_no_sdk);
      diagnose(SourceLoc(), diag::sema_no_import_no_sdk_xcrun);
    }
    return;
  }

  ID->setModule(M);

  Module *topLevelModule;
  if (ID->getModulePath().size() == 1) {
    topLevelModule = M;
  } else {
    // If we imported a submodule, import the top-level module as well.
    Identifier topLevelName = ID->getModulePath().front().first;
    topLevelModule = Context.getLoadedModule(topLevelName);
    assert(topLevelModule && "top-level module missing");
  }

  auto *testableAttr = ID->getAttrs().getAttribute<TestableAttr>();
  if (testableAttr && !topLevelModule->isTestingEnabled() &&
      Context.LangOpts.EnableTestableAttrRequiresTestableModule) {
    diagnose(ID->getModulePath().front().second, diag::module_not_testable,
             topLevelModule->getName());
    testableAttr->setInvalid();
  }

  ImportOptions options;
  if (ID->isExported())
    options |= SourceFile::ImportFlags::Exported;
  if (testableAttr)
    options |= SourceFile::ImportFlags::Testable;
  imports.push_back({ { ID->getDeclPath(), M }, options });

  if (topLevelModule != M)
    imports.push_back({ { ID->getDeclPath(), topLevelModule }, options });

  if (ID->getImportKind() != ImportKind::Module) {
    // If we're importing a specific decl, validate the import kind.
    using namespace namelookup;
    auto declPath = ID->getDeclPath();

    // FIXME: Doesn't handle scoped testable imports correctly.
    assert(declPath.size() == 1 && "can't handle sub-decl imports");
    SmallVector<ValueDecl *, 8> decls;
    lookupInModule(topLevelModule, declPath, declPath.front().first, decls,
                   NLKind::QualifiedLookup, ResolutionKind::Overloadable,
                   /*resolver*/nullptr, &SF);

    if (decls.empty()) {
      diagnose(ID, diag::no_decl_in_module)
        .highlight(SourceRange(declPath.front().second,
                               declPath.back().second));
      return;
    }

    ID->setDecls(Context.AllocateCopy(decls));

    Optional<ImportKind> actualKind = ImportDecl::findBestImportKind(decls);
    if (!actualKind.hasValue()) {
      // FIXME: print entire module name?
      diagnose(ID, diag::ambiguous_decl_in_module,
               declPath.front().first, M->getName());
      for (auto next : decls)
        diagnose(next, diag::found_candidate);

    } else if (!isCompatibleImportKind(ID->getImportKind(), *actualKind)) {
//.........这里部分代码省略.........

/// Utility function for reservePreviousStackSlotForValue. Tries to find
/// stack slot index to which we have spilled value for previous statepoints.
/// LookUpDepth specifies maximum DFS depth this function is allowed to look.
static Optional<int> findPreviousSpillSlot(const Value *Val,
                                           SelectionDAGBuilder &Builder,
                                           int LookUpDepth) {
  // Can not look any further - give up now
  if (LookUpDepth <= 0)
    return None;

  // Spill location is known for gc relocates
  if (const auto *Relocate = dyn_cast<GCRelocateInst>(Val)) {
    const auto &SpillMap =
        Builder.FuncInfo.StatepointSpillMaps[Relocate->getStatepoint()];

    auto It = SpillMap.find(Relocate->getDerivedPtr());
    if (It == SpillMap.end())
      return None;

    return It->second;
  }

  // Look through bitcast instructions.
  if (const BitCastInst *Cast = dyn_cast<BitCastInst>(Val))
    return findPreviousSpillSlot(Cast->getOperand(0), Builder, LookUpDepth - 1);

  // Look through phi nodes
  // All incoming values should have same known stack slot, otherwise result
  // is unknown.
  if (const PHINode *Phi = dyn_cast<PHINode>(Val)) {
    Optional<int> MergedResult = None;

    for (auto &IncomingValue : Phi->incoming_values()) {
      Optional<int> SpillSlot =
          findPreviousSpillSlot(IncomingValue, Builder, LookUpDepth - 1);
      if (!SpillSlot.hasValue())
        return None;

      if (MergedResult.hasValue() && *MergedResult != *SpillSlot)
        return None;

      MergedResult = SpillSlot;
    }
    return MergedResult;
  }

  // TODO: We can do better for PHI nodes. In cases like this:
  //   ptr = phi(relocated_pointer, not_relocated_pointer)
  //   statepoint(ptr)
  // We will return that stack slot for ptr is unknown. And later we might
  // assign different stack slots for ptr and relocated_pointer. This limits
  // llvm's ability to remove redundant stores.
  // Unfortunately it's hard to accomplish in current infrastructure.
  // We use this function to eliminate spill store completely, while
  // in example we still need to emit store, but instead of any location
  // we need to use special "preferred" location.

  // TODO: handle simple updates.  If a value is modified and the original
  // value is no longer live, it would be nice to put the modified value in the
  // same slot.  This allows folding of the memory accesses for some
  // instructions types (like an increment).
  //   statepoint (i)
  //   i1 = i+1
  //   statepoint (i1)
  // However we need to be careful for cases like this:
  //   statepoint(i)
  //   i1 = i+1
  //   statepoint(i, i1)
  // Here we want to reserve spill slot for 'i', but not for 'i+1'. If we just
  // put handling of simple modifications in this function like it's done
  // for bitcasts we might end up reserving i's slot for 'i+1' because order in
  // which we visit values is unspecified.

  // Don't know any information about this instruction
  return None;
}

void CFNumberChecker::checkPreStmt(const CallExpr *CE,
                                         CheckerContext &C) const {
  ProgramStateRef state = C.getState();
  const FunctionDecl *FD = C.getCalleeDecl(CE);
  if (!FD)
    return;

  ASTContext &Ctx = C.getASTContext();
  if (!ICreate) {
    ICreate = &Ctx.Idents.get("CFNumberCreate");
    IGetValue = &Ctx.Idents.get("CFNumberGetValue");
  }
  if (!(FD->getIdentifier() == ICreate || FD->getIdentifier() == IGetValue) ||
      CE->getNumArgs() != 3)
    return;

  // Get the value of the "theType" argument.
  const LocationContext *LCtx = C.getLocationContext();
  SVal TheTypeVal = state->getSVal(CE->getArg(1), LCtx);

  // FIXME: We really should allow ranges of valid theType values, and
  //   bifurcate the state appropriately.
  Optional<nonloc::ConcreteInt> V = TheTypeVal.getAs<nonloc::ConcreteInt>();
  if (!V)
    return;

  uint64_t NumberKind = V->getValue().getLimitedValue();
  Optional<uint64_t> OptCFNumberSize = GetCFNumberSize(Ctx, NumberKind);

  // FIXME: In some cases we can emit an error.
  if (!OptCFNumberSize)
    return;

  uint64_t CFNumberSize = *OptCFNumberSize;

  // Look at the value of the integer being passed by reference.  Essentially
  // we want to catch cases where the value passed in is not equal to the
  // size of the type being created.
  SVal TheValueExpr = state->getSVal(CE->getArg(2), LCtx);

  // FIXME: Eventually we should handle arbitrary locations.  We can do this
  //  by having an enhanced memory model that does low-level typing.
  Optional<loc::MemRegionVal> LV = TheValueExpr.getAs<loc::MemRegionVal>();
  if (!LV)
    return;

  const TypedValueRegion* R = dyn_cast<TypedValueRegion>(LV->stripCasts());
  if (!R)
    return;

  QualType T = Ctx.getCanonicalType(R->getValueType());

  // FIXME: If the pointee isn't an integer type, should we flag a warning?
  //  People can do weird stuff with pointers.

  if (!T->isIntegralOrEnumerationType())
    return;

  uint64_t PrimitiveTypeSize = Ctx.getTypeSize(T);

  if (PrimitiveTypeSize == CFNumberSize)
    return;

  // FIXME: We can actually create an abstract "CFNumber" object that has
  //  the bits initialized to the provided values.
  ExplodedNode *N = C.generateNonFatalErrorNode();
  if (N) {
    SmallString<128> sbuf;
    llvm::raw_svector_ostream os(sbuf);
    bool isCreate = (FD->getIdentifier() == ICreate);

    if (isCreate) {
      os << (PrimitiveTypeSize == 8 ? "An " : "A ")
         << PrimitiveTypeSize << "-bit integer is used to initialize a "
         << "CFNumber object that represents "
         << (CFNumberSize == 8 ? "an " : "a ")
         << CFNumberSize << "-bit integer; ";
    } else {
      os << "A CFNumber object that represents "
         << (CFNumberSize == 8 ? "an " : "a ")
         << CFNumberSize << "-bit integer is used to initialize "
         << (PrimitiveTypeSize == 8 ? "an " : "a ")
         << PrimitiveTypeSize << "-bit integer; ";
    }

    if (PrimitiveTypeSize < CFNumberSize)
      os << (CFNumberSize - PrimitiveTypeSize)
      << " bits of the CFNumber value will "
      << (isCreate ? "be garbage." : "overwrite adjacent storage.");
    else
      os << (PrimitiveTypeSize - CFNumberSize)
      << " bits of the integer value will be "
      << (isCreate ? "lost." : "garbage.");

    if (!BT)
      BT.reset(new APIMisuse(this, "Bad use of CFNumber APIs"));

    auto report = llvm::make_unique<BugReport>(*BT, os.str(), N);
    report->addRange(CE->getArg(2)->getSourceRange());
    C.emitReport(std::move(report));
//.........这里部分代码省略.........

void Messaging::onTelegram(const Optional<CoAP::Telegram>& telegram) {
  auto message = messageFromTelegram(telegram);
  if (message) onMessage(message.value(), telegram.value().getIP(), telegram.value().getPort());
}

//.........这里部分代码省略.........
      continue;
    }


    // Go through all users of the constant and try to fold them.
    FoldedUsers.clear();
    for (auto Use : I->getUses()) {
      SILInstruction *User = Use->getUser();
      DEBUG(llvm::dbgs() << "    User: " << *User);

      // It is possible that we had processed this user already. Do not try
      // to fold it again if we had previously produced an error while folding
      // it.  It is not always possible to fold an instruction in case of error.
      if (ErrorSet.count(User))
        continue;

      // Some constant users may indirectly cause folding of their users.
      if (isa<StructInst>(User) || isa<TupleInst>(User)) {
        WorkList.insert(User);
        continue;
      }

      // Always consider cond_fail instructions as potential for DCE.  If the
      // expression feeding them is false, they are dead.  We can't handle this
      // as part of the constant folding logic, because there is no value
      // they can produce (other than empty tuple, which is wasteful).
      if (isa<CondFailInst>(User))
        FoldedUsers.insert(User);

      // Initialize ResultsInError as a None optional.
      //
      // We are essentially using this optional to represent 3 states: true,
      // false, and n/a.
      Optional<bool> ResultsInError;

      // If we are asked to emit diagnostics, override ResultsInError with a
      // Some optional initialized to false.
      if (EnableDiagnostics)
        ResultsInError = false;

      // Try to fold the user. If ResultsInError is None, we do not emit any
      // diagnostics. If ResultsInError is some, we use it as our return value.
      SILValue C = constantFoldInstruction(*User, ResultsInError);

      // If we did not pass in a None and the optional is set to true, add the
      // user to our error set.
      if (ResultsInError.hasValue() && ResultsInError.getValue())
        ErrorSet.insert(User);

      // We failed to constant propagate... continue...
      if (!C)
        continue;

      // Ok, we have succeeded. Add user to the FoldedUsers list and perform the
      // necessary cleanups, RAUWs, etc.
      FoldedUsers.insert(User);
      ++NumInstFolded;

      InvalidateInstructions = true;

      // If the constant produced a tuple, be smarter than RAUW: explicitly nuke
      // any tuple_extract instructions using the apply.  This is a common case
      // for functions returning multiple values.
      if (auto *TI = dyn_cast<TupleInst>(C)) {
        for (auto UI = User->use_begin(), E = User->use_end(); UI != E;) {
          Operand *O = *UI++;

void
MessagePort::PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
                         const Optional<Sequence<JS::Value>>& aTransferable,
                         ErrorResult& aRv)
{
  // We *must* clone the data here, or the JS::Value could be modified
  // by script

  JS::Rooted<JS::Value> transferable(aCx, JS::UndefinedValue());
  if (aTransferable.WasPassed()) {
    const Sequence<JS::Value>& realTransferable = aTransferable.Value();

    // Here we want to check if the transerable object list contains
    // this port. No other checks are done.
    for (const JS::Value& value : realTransferable) {
      if (!value.isObject()) {
        continue;
      }

      MessagePort* port = nullptr;
      nsresult rv = UNWRAP_OBJECT(MessagePort, &value.toObject(), port);
      if (NS_FAILED(rv)) {
        continue;
      }

      if (port == this) {
        aRv.Throw(NS_ERROR_DOM_DATA_CLONE_ERR);
        return;
      }
    }

    // The input sequence only comes from the generated bindings code, which
    // ensures it is rooted.
    JS::HandleValueArray elements =
      JS::HandleValueArray::fromMarkedLocation(realTransferable.Length(),
                                               realTransferable.Elements());

    JSObject* array =
      JS_NewArrayObject(aCx, elements);
    if (!array) {
      aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
      return;
    }

    transferable.setObject(*array);
  }

  RefPtr<SharedMessagePortMessage> data = new SharedMessagePortMessage();

  UniquePtr<AbstractTimelineMarker> start;
  UniquePtr<AbstractTimelineMarker> end;
  RefPtr<TimelineConsumers> timelines = TimelineConsumers::Get();
  bool isTimelineRecording = timelines && !timelines->IsEmpty();

  if (isTimelineRecording) {
    start = MakeUnique<MessagePortTimelineMarker>(
      ProfileTimelineMessagePortOperationType::SerializeData,
      MarkerTracingType::START);
  }

  data->Write(aCx, aMessage, transferable, aRv);

  if (isTimelineRecording) {
    end = MakeUnique<MessagePortTimelineMarker>(
      ProfileTimelineMessagePortOperationType::SerializeData,
      MarkerTracingType::END);
    timelines->AddMarkerForAllObservedDocShells(start);
    timelines->AddMarkerForAllObservedDocShells(end);
  }

  if (NS_WARN_IF(aRv.Failed())) {
    return;
  }

  // This message has to be ignored.
  if (mState > eStateEntangled) {
    return;
  }

  // If we are unshipped we are connected to the other port on the same thread.
  if (mState == eStateUnshippedEntangled) {
    MOZ_ASSERT(mUnshippedEntangledPort);
    mUnshippedEntangledPort->mMessages.AppendElement(data);
    mUnshippedEntangledPort->Dispatch();
    return;
  }

  // Not entangled yet, but already closed/disentangled.
  if (mState == eStateEntanglingForDisentangle ||
      mState == eStateEntanglingForClose) {
    return;
  }

  RemoveDocFromBFCache();

  // Not entangled yet.
  if (mState == eStateEntangling) {
    mMessagesForTheOtherPort.AppendElement(data);
    return;
  }
//.........这里部分代码省略.........