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DSGraphs while they are forwarding. When the last reference to the forwarding node is dropped, the forwarding node is autodeleted. This should simplify removeTriviallyDead nodes, and is only (efficiently) possible because we are using an ilist of dsnodes now. llvm-svn: 11175
449 lines
16 KiB
C++
449 lines
16 KiB
C++
//===- DSNode.h - Node definition for datastructure graphs ------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// Data structure graph nodes and some implementation of DSNodeHandle.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_ANALYSIS_DSNODE_H
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#define LLVM_ANALYSIS_DSNODE_H
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#include "llvm/Analysis/DSSupport.h"
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namespace llvm {
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template<typename BaseType>
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class DSNodeIterator; // Data structure graph traversal iterator
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class TargetData;
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//===----------------------------------------------------------------------===//
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/// DSNode - Data structure node class
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///
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/// This class represents an untyped memory object of Size bytes. It keeps
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/// track of any pointers that have been stored into the object as well as the
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/// different types represented in this object.
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///
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class DSNode {
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/// NumReferrers - The number of DSNodeHandles pointing to this node... if
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/// this is a forwarding node, then this is the number of node handles which
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/// are still forwarding over us.
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///
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unsigned NumReferrers;
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/// ForwardNH - This NodeHandle contain the node (and offset into the node)
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/// that this node really is. When nodes get folded together, the node to be
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/// eliminated has these fields filled in, otherwise ForwardNH.getNode() is
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/// null.
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DSNodeHandle ForwardNH;
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/// Next, Prev - These instance variables are used to keep the node on a
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/// doubly-linked ilist in the DSGraph.
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DSNode *Next, *Prev;
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friend class ilist_traits<DSNode>;
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/// Size - The current size of the node. This should be equal to the size of
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/// the current type record.
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///
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unsigned Size;
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/// ParentGraph - The graph this node is currently embedded into.
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///
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DSGraph *ParentGraph;
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/// Ty - Keep track of the current outer most type of this object, in addition
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/// to whether or not it has been indexed like an array or not. If the
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/// isArray bit is set, the node cannot grow.
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///
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const Type *Ty; // The type itself...
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/// Links - Contains one entry for every sizeof(void*) bytes in this memory
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/// object. Note that if the node is not a multiple of size(void*) bytes
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/// large, that there is an extra entry for the "remainder" of the node as
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/// well. For this reason, nodes of 1 byte in size do have one link.
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///
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std::vector<DSNodeHandle> Links;
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/// Globals - The list of global values that are merged into this node.
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///
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std::vector<GlobalValue*> Globals;
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void operator=(const DSNode &); // DO NOT IMPLEMENT
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DSNode(const DSNode &); // DO NOT IMPLEMENT
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public:
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enum NodeTy {
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ShadowNode = 0, // Nothing is known about this node...
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AllocaNode = 1 << 0, // This node was allocated with alloca
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HeapNode = 1 << 1, // This node was allocated with malloc
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GlobalNode = 1 << 2, // This node was allocated by a global var decl
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UnknownNode = 1 << 3, // This node points to unknown allocated memory
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Incomplete = 1 << 4, // This node may not be complete
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Modified = 1 << 5, // This node is modified in this context
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Read = 1 << 6, // This node is read in this context
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Array = 1 << 7, // This node is treated like an array
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//#ifndef NDEBUG
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DEAD = 1 << 8, // This node is dead and should not be pointed to
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//#endif
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Composition = AllocaNode | HeapNode | GlobalNode | UnknownNode,
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};
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/// NodeType - A union of the above bits. "Shadow" nodes do not add any flags
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/// to the nodes in the data structure graph, so it is possible to have nodes
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/// with a value of 0 for their NodeType.
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///
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private:
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unsigned short NodeType;
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public:
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/// DSNode ctor - Create a node of the specified type, inserting it into the
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/// specified graph.
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DSNode(const Type *T, DSGraph *G);
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/// DSNode "copy ctor" - Copy the specified node, inserting it into the
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/// specified graph. If NullLinks is true, then null out all of the links,
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/// but keep the same number of them. This can be used for efficiency if the
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/// links are just going to be clobbered anyway.
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DSNode(const DSNode &, DSGraph *G, bool NullLinks = false);
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~DSNode() {
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dropAllReferences();
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assert(hasNoReferrers() && "Referrers to dead node exist!");
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}
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// Iterator for graph interface... Defined in DSGraphTraits.h
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typedef DSNodeIterator<DSNode> iterator;
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typedef DSNodeIterator<const DSNode> const_iterator;
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inline iterator begin();
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inline iterator end();
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inline const_iterator begin() const;
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inline const_iterator end() const;
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//===--------------------------------------------------
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// Accessors
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/// getSize - Return the maximum number of bytes occupied by this object...
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///
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unsigned getSize() const { return Size; }
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// getType - Return the node type of this object...
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const Type *getType() const { return Ty; }
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bool isArray() const { return NodeType & Array; }
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/// hasNoReferrers - Return true if nothing is pointing to this node at all.
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///
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bool hasNoReferrers() const { return getNumReferrers() == 0; }
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/// getNumReferrers - This method returns the number of referrers to the
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/// current node. Note that if this node is a forwarding node, this will
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/// return the number of nodes forwarding over the node!
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unsigned getNumReferrers() const { return NumReferrers; }
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DSGraph *getParentGraph() const { return ParentGraph; }
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void setParentGraph(DSGraph *G) { ParentGraph = G; }
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/// getTargetData - Get the target data object used to construct this node.
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///
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const TargetData &getTargetData() const;
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/// getForwardNode - This method returns the node that this node is forwarded
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/// to, if any.
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DSNode *getForwardNode() const { return ForwardNH.getNode(); }
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/// isForwarding - Return true if this node is forwarding to another.
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///
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bool isForwarding() const { return !ForwardNH.isNull(); }
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/// stopForwarding - When the last reference to this forwarding node has been
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/// dropped, delete the node.
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void stopForwarding() {
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assert(isForwarding() &&
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"Node isn't forwarding, cannot stopForwarding!");
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ForwardNH.setNode(0);
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assert(ParentGraph == 0 &&
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"Forwarding nodes must have been removed from graph!");
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delete this;
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}
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/// hasLink - Return true if this memory object has a link in slot #LinkNo
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///
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bool hasLink(unsigned Offset) const {
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assert((Offset & ((1 << DS::PointerShift)-1)) == 0 &&
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"Pointer offset not aligned correctly!");
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unsigned Index = Offset >> DS::PointerShift;
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assert(Index < Links.size() && "Link index is out of range!");
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return Links[Index].getNode();
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}
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/// getLink - Return the link at the specified offset.
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DSNodeHandle &getLink(unsigned Offset) {
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assert((Offset & ((1 << DS::PointerShift)-1)) == 0 &&
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"Pointer offset not aligned correctly!");
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unsigned Index = Offset >> DS::PointerShift;
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assert(Index < Links.size() && "Link index is out of range!");
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return Links[Index];
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}
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const DSNodeHandle &getLink(unsigned Offset) const {
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assert((Offset & ((1 << DS::PointerShift)-1)) == 0 &&
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"Pointer offset not aligned correctly!");
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unsigned Index = Offset >> DS::PointerShift;
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assert(Index < Links.size() && "Link index is out of range!");
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return Links[Index];
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}
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/// getNumLinks - Return the number of links in a node...
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///
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unsigned getNumLinks() const { return Links.size(); }
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/// mergeTypeInfo - This method merges the specified type into the current
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/// node at the specified offset. This may update the current node's type
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/// record if this gives more information to the node, it may do nothing to
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/// the node if this information is already known, or it may merge the node
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/// completely (and return true) if the information is incompatible with what
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/// is already known.
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///
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/// This method returns true if the node is completely folded, otherwise
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/// false.
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///
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bool mergeTypeInfo(const Type *Ty, unsigned Offset,
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bool FoldIfIncompatible = true);
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/// foldNodeCompletely - If we determine that this node has some funny
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/// behavior happening to it that we cannot represent, we fold it down to a
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/// single, completely pessimistic, node. This node is represented as a
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/// single byte with a single TypeEntry of "void" with isArray = true.
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///
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void foldNodeCompletely();
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/// isNodeCompletelyFolded - Return true if this node has been completely
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/// folded down to something that can never be expanded, effectively losing
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/// all of the field sensitivity that may be present in the node.
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///
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bool isNodeCompletelyFolded() const;
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/// setLink - Set the link at the specified offset to the specified
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/// NodeHandle, replacing what was there. It is uncommon to use this method,
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/// instead one of the higher level methods should be used, below.
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///
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void setLink(unsigned Offset, const DSNodeHandle &NH) {
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assert((Offset & ((1 << DS::PointerShift)-1)) == 0 &&
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"Pointer offset not aligned correctly!");
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unsigned Index = Offset >> DS::PointerShift;
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assert(Index < Links.size() && "Link index is out of range!");
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Links[Index] = NH;
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}
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/// getPointerSize - Return the size of a pointer for the current target.
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///
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unsigned getPointerSize() const { return DS::PointerSize; }
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/// addEdgeTo - Add an edge from the current node to the specified node. This
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/// can cause merging of nodes in the graph.
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///
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void addEdgeTo(unsigned Offset, const DSNodeHandle &NH);
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/// mergeWith - Merge this node and the specified node, moving all links to
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/// and from the argument node into the current node, deleting the node
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/// argument. Offset indicates what offset the specified node is to be merged
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/// into the current node.
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///
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/// The specified node may be a null pointer (in which case, nothing happens).
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///
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void mergeWith(const DSNodeHandle &NH, unsigned Offset);
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/// addGlobal - Add an entry for a global value to the Globals list. This
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/// also marks the node with the 'G' flag if it does not already have it.
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///
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void addGlobal(GlobalValue *GV);
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void mergeGlobals(const std::vector<GlobalValue*> &RHS);
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const std::vector<GlobalValue*> &getGlobals() const { return Globals; }
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typedef std::vector<GlobalValue*>::const_iterator global_iterator;
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global_iterator global_begin() const { return Globals.begin(); }
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global_iterator global_end() const { return Globals.end(); }
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/// maskNodeTypes - Apply a mask to the node types bitfield.
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///
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void maskNodeTypes(unsigned Mask) {
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NodeType &= Mask;
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}
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void mergeNodeFlags(unsigned RHS) {
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NodeType |= RHS;
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}
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/// getNodeFlags - Return all of the flags set on the node. If the DEAD flag
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/// is set, hide it from the caller.
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unsigned getNodeFlags() const { return NodeType & ~DEAD; }
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bool isAllocaNode() const { return NodeType & AllocaNode; }
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bool isHeapNode() const { return NodeType & HeapNode; }
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bool isGlobalNode() const { return NodeType & GlobalNode; }
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bool isUnknownNode() const { return NodeType & UnknownNode; }
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bool isModified() const { return NodeType & Modified; }
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bool isRead() const { return NodeType & Read; }
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bool isIncomplete() const { return NodeType & Incomplete; }
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bool isComplete() const { return !isIncomplete(); }
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bool isDeadNode() const { return NodeType & DEAD; }
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DSNode *setAllocaNodeMarker() { NodeType |= AllocaNode; return this; }
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DSNode *setHeapNodeMarker() { NodeType |= HeapNode; return this; }
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DSNode *setGlobalNodeMarker() { NodeType |= GlobalNode; return this; }
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DSNode *setUnknownNodeMarker() { NodeType |= UnknownNode; return this; }
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DSNode *setIncompleteMarker() { NodeType |= Incomplete; return this; }
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DSNode *setModifiedMarker() { NodeType |= Modified; return this; }
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DSNode *setReadMarker() { NodeType |= Read; return this; }
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void makeNodeDead() {
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Globals.clear();
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assert(hasNoReferrers() && "Dead node shouldn't have refs!");
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NodeType = DEAD;
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}
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/// forwardNode - Mark this node as being obsolete, and all references to it
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/// should be forwarded to the specified node and offset.
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///
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void forwardNode(DSNode *To, unsigned Offset);
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void print(std::ostream &O, const DSGraph *G) const;
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void dump() const;
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void assertOK() const;
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void dropAllReferences() {
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Links.clear();
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if (isForwarding())
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ForwardNH.setNode(0);
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}
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/// remapLinks - Change all of the Links in the current node according to the
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/// specified mapping.
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void remapLinks(hash_map<const DSNode*, DSNodeHandle> &OldNodeMap);
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/// markReachableNodes - This method recursively traverses the specified
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/// DSNodes, marking any nodes which are reachable. All reachable nodes it
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/// adds to the set, which allows it to only traverse visited nodes once.
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///
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void markReachableNodes(hash_set<DSNode*> &ReachableNodes);
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private:
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friend class DSNodeHandle;
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// static mergeNodes - Helper for mergeWith()
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static void MergeNodes(DSNodeHandle& CurNodeH, DSNodeHandle& NH);
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};
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//===----------------------------------------------------------------------===//
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// Define the ilist_traits specialization for the DSGraph ilist.
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//
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template<>
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struct ilist_traits<DSNode> {
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static DSNode *getPrev(const DSNode *N) { return N->Prev; }
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static DSNode *getNext(const DSNode *N) { return N->Next; }
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static void setPrev(DSNode *N, DSNode *Prev) { N->Prev = Prev; }
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static void setNext(DSNode *N, DSNode *Next) { N->Next = Next; }
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static DSNode *createNode() { return new DSNode(0,0); }
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//static DSNode *createNode(const DSNode &V) { return new DSNode(V); }
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void addNodeToList(DSNode *NTy) {}
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void removeNodeFromList(DSNode *NTy) {}
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void transferNodesFromList(iplist<DSNode, ilist_traits> &L2,
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ilist_iterator<DSNode> first,
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ilist_iterator<DSNode> last) {}
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};
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template<>
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struct ilist_traits<const DSNode> : public ilist_traits<DSNode> {};
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//===----------------------------------------------------------------------===//
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// Define inline DSNodeHandle functions that depend on the definition of DSNode
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//
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inline DSNode *DSNodeHandle::getNode() const {
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assert((!N || Offset < N->Size || (N->Size == 0 && Offset == 0) ||
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N->isForwarding()) && "Node handle offset out of range!");
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if (N == 0 || !N->isForwarding())
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return N;
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return HandleForwarding();
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}
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inline void DSNodeHandle::setNode(DSNode *n) const {
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assert(!n || !n->isForwarding() && "Cannot set node to a forwarded node!");
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if (N) getNode()->NumReferrers--;
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N = n;
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if (N) {
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N->NumReferrers++;
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if (Offset >= N->Size) {
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assert((Offset == 0 || N->Size == 1) &&
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"Pointer to non-collapsed node with invalid offset!");
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Offset = 0;
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}
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}
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assert(!N || ((N->NodeType & DSNode::DEAD) == 0));
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assert((!N || Offset < N->Size || (N->Size == 0 && Offset == 0) ||
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N->isForwarding()) && "Node handle offset out of range!");
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}
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inline bool DSNodeHandle::hasLink(unsigned Num) const {
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assert(N && "DSNodeHandle does not point to a node yet!");
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return getNode()->hasLink(Num+Offset);
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}
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/// getLink - Treat this current node pointer as a pointer to a structure of
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/// some sort. This method will return the pointer a mem[this+Num]
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///
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inline const DSNodeHandle &DSNodeHandle::getLink(unsigned Off) const {
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assert(N && "DSNodeHandle does not point to a node yet!");
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return getNode()->getLink(Offset+Off);
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}
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inline DSNodeHandle &DSNodeHandle::getLink(unsigned Off) {
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assert(N && "DSNodeHandle does not point to a node yet!");
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return getNode()->getLink(Off+Offset);
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}
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inline void DSNodeHandle::setLink(unsigned Off, const DSNodeHandle &NH) {
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assert(N && "DSNodeHandle does not point to a node yet!");
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getNode()->setLink(Off+Offset, NH);
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}
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/// addEdgeTo - Add an edge from the current node to the specified node. This
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/// can cause merging of nodes in the graph.
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///
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inline void DSNodeHandle::addEdgeTo(unsigned Off, const DSNodeHandle &Node) {
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assert(N && "DSNodeHandle does not point to a node yet!");
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getNode()->addEdgeTo(Off+Offset, Node);
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}
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/// mergeWith - Merge the logical node pointed to by 'this' with the node
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/// pointed to by 'N'.
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///
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inline void DSNodeHandle::mergeWith(const DSNodeHandle &Node) const {
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if (!isNull())
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getNode()->mergeWith(Node, Offset);
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else { // No node to merge with, so just point to Node
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Offset = 0;
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setNode(Node.getNode());
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Offset = Node.getOffset();
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}
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}
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} // End llvm namespace
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#endif
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