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//===- DSNode.h - Node definition for datastructure graphs ------*- C++ -*-===//
// The LLVM Compiler Infrastructure
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
// Data structure graph nodes and some implementation of DSNodeHandle.
#include "rdsa/DSSupport.h"
#include "rdsa/DSFlags.h"
#include "llvm/Support/Streams.h"
#include "poolalloc/ADT/HashExtras.h"
namespace llvm {
template<typename BaseType>
class DSNodeIterator; // Data structure graph traversal iterator
class DataLayout;
/// DSNode - Data structure node class
/// This class represents an untyped memory object of Size bytes. It keeps
/// track of any pointers that have been stored into the object as well as the
/// different types represented in this object.
class DSNode {
/// NumReferrers - The number of DSNodeHandles pointing to this node... if
/// this is a forwarding node, then this is the number of node handles which
/// are still forwarding over us.
unsigned NumReferrers;
/// ForwardNH - This NodeHandle contain the node (and offset into the node)
/// that this node really is. When nodes get folded together, the node to be
/// eliminated has these fields filled in, otherwise ForwardNH.getNode() is
/// null.
DSNodeHandle ForwardNH;
/// Next, Prev - These instance variables are used to keep the node on a
/// doubly-linked ilist in the DSGraph.
DSNode *Next, *Prev;
friend struct ilist_traits<DSNode>;
/// Size - The current size of the node. This should be equal to the size of
/// the current type record.
unsigned Size;
/// ParentGraph - The graph this node is currently embedded into.
DSGraph *ParentGraph;
/// Ty - Keep track of the current outer most type of this object, in addition
/// to whether or not it has been indexed like an array or not. If the
/// isArray bit is set, the node cannot grow.
const Type *Ty; // The type itself...
/// Links - Contains one entry for every sizeof(void*) bytes in this memory
/// object. Note that if the node is not a multiple of size(void*) bytes
/// large, that there is an extra entry for the "remainder" of the node as
/// well. For this reason, nodes of 1 byte in size do have one link.
std::vector<DSNodeHandle> Links;
void operator=(const DSNode &); // DO NOT IMPLEMENT
DSNode(const DSNode &); // DO NOT IMPLEMENT
/// Globals - The list of global values that are merged into this node.
std::vector<const GlobalValue*> Globals;
DSFlags NodeType;
/// DSNode ctor - Create a node of the specified type, inserting it into the
/// specified graph.
DSNode(const Type *T, DSGraph *G);
/// DSNode "copy ctor" - Copy the specified node, inserting it into the
/// specified graph. If NullLinks is true, then null out all of the links,
/// but keep the same number of them. This can be used for efficiency if the
/// links are just going to be clobbered anyway.
DSNode(const DSNode &, DSGraph *G, bool NullLinks = false);
#if 0
~DSNode() {
assert(hasNoReferrers() && "Referrers to dead node exist!");
// Iterator for graph interface... Defined in DSGraphTraits.h
typedef DSNodeIterator<DSNode> iterator;
typedef DSNodeIterator<const DSNode> const_iterator;
inline iterator begin();
inline iterator end();
inline const_iterator begin() const;
inline const_iterator end() const;
// Accessors
/// getSize - Return the maximum number of bytes occupied by this object...
unsigned getSize() const { return Size; }
/// getType - Return the node type of this object...
const Type *getType() const { return Ty; }
/// hasNoReferrers - Return true if nothing is pointing to this node at all.
bool hasNoReferrers() const { return getNumReferrers() == 0; }
/// getNumReferrers - This method returns the number of referrers to the
/// current node. Note that if this node is a forwarding node, this will
/// return the number of nodes forwarding over the node!
unsigned getNumReferrers() const { return NumReferrers; }
DSGraph *getParentGraph() const { return ParentGraph; }
void setParentGraph(DSGraph *G) { ParentGraph = G; }
/// getDataLayout - Get the target data object used to construct this node.
const DataLayout &getDataLayout() const;
/// getForwardNode - This method returns the node that this node is forwarded
/// to, if any.
DSNode *getForwardNode() const { return ForwardNH.getNode(); }
/// isForwarding - Return true if this node is forwarding to another.
bool isForwarding() const { return !ForwardNH.isNull(); }
/// stopForwarding - When the last reference to this forwarding node has been
/// dropped, delete the node.
void stopForwarding() {
assert(isForwarding() &&
"Node isn't forwarding, cannot stopForwarding()!");
ForwardNH.setTo(0, 0);
assert(ParentGraph == 0 &&
"Forwarding nodes must have been removed from graph!");
delete this;
/// hasLink - Return true if this memory object has a link in slot LinkNo
bool hasLink(unsigned Offset) const {
unsigned Index = Offset;
assert(Index < Links.size() && "Link index is out of range!");
return Links[Index].getNode();
/// getLink - Return the link at the specified offset.
DSNodeHandle &getLink(unsigned Offset) {
unsigned Index = Offset;
assert(Index < Links.size() && "Link index is out of range!");
return Links[Index];
const DSNodeHandle &getLink(unsigned Offset) const {
unsigned Index = Offset;
assert(Index < Links.size() && "Link index is out of range!");
return Links[Index];
/// getNumLinks - Return the number of links in a node...
unsigned getNumLinks() const { return Links.size(); }
/// edge_* - Provide iterators for accessing outgoing edges. Some outgoing
/// edges may be null.
typedef std::vector<DSNodeHandle>::iterator edge_iterator;
typedef std::vector<DSNodeHandle>::const_iterator const_edge_iterator;
edge_iterator edge_begin() { return Links.begin(); }
edge_iterator edge_end() { return Links.end(); }
const_edge_iterator edge_begin() const { return Links.begin(); }
const_edge_iterator edge_end() const { return Links.end(); }
/// mergeTypeInfo - This method merges the specified type into the current
/// node at the specified offset. This may update the current node's type
/// record if this gives more information to the node, it may do nothing to
/// the node if this information is already known, or it may merge the node
/// completely (and return true) if the information is incompatible with what
/// is already known.
/// This method returns true if the node is completely folded, otherwise
/// false.
bool mergeTypeInfo(const Type *Ty, unsigned Offset,
bool FoldIfIncompatible = true);
/// foldNodeCompletely - If we determine that this node has some funny
/// behavior happening to it that we cannot represent, we fold it down to a
/// single, completely pessimistic, node. This node is represented as a
/// single byte with a single TypeEntry of "void" with isArray = true.
void foldNodeCompletely();
/// isNodeCompletelyFolded - Return true if this node has been completely
/// folded down to something that can never be expanded, effectively losing
/// all of the field sensitivity that may be present in the node.
bool isNodeCompletelyFolded() const;
/// setLink - Set the link at the specified offset to the specified
/// NodeHandle, replacing what was there. It is uncommon to use this method,
/// instead one of the higher level methods should be used, below.
void setLink(unsigned Offset, const DSNodeHandle &NH) {
unsigned Index = Offset;
assert(Index < Links.size() && "Link index is out of range!");
Links[Index] = NH;
/// addEdgeTo - Add an edge from the current node to the specified node. This
/// can cause merging of nodes in the graph.
void addEdgeTo(unsigned Offset, const DSNodeHandle &NH);
/// mergeWith - Merge this node and the specified node, moving all links to
/// and from the argument node into the current node, deleting the node
/// argument. Offset indicates what offset the specified node is to be merged
/// into the current node.
/// The specified node may be a null pointer (in which case, nothing happens).
void mergeWith(const DSNodeHandle &NH, unsigned Offset);
/// addGlobal - Add an entry for a global value to the Globals list.
/// This also marks the node with the 'G' flag if it does not
/// already have it.
void addGlobal(const GlobalValue *GV);
/// addFunction - Add an entry for a function value to the
/// Functionss list. This also marks the node with the 'F' flag if
/// it does not already have it.
void addFunction(const Function* FV);
/// removeGlobal - Remove the specified global that is explicitly in the
/// globals list.
void removeGlobal(const GlobalValue *GV);
void mergeGlobals(const DSNode& RHS);
void clearGlobals() { Globals.clear(); }
bool isEmptyGlobals() const { return Globals.empty(); }
unsigned numGlobals() const { return Globals.size(); }
/// addFullGlobalsList - Compute the full set of global values that are
/// represented by this node. Unlike getGlobalsList(), this requires fair
/// amount of work to compute, so don't treat this method call as free.
void addFullGlobalsList(std::vector<const GlobalValue*> &List) const;
/// addFullFunctionList - Identical to addFullGlobalsList, but only return the
/// functions in the full list.
void addFullFunctionList(std::vector<const Function*> &List) const;
/// globals_iterator/begin/end - Provide iteration methods over the global
/// value leaders set that is merged into this node. Like the getGlobalsList
/// method, these iterators do not return globals that are part of the
/// equivalence classes for globals in this node, but aren't leaders.
typedef std::vector<const GlobalValue*>::const_iterator globals_iterator;
globals_iterator globals_begin() const { return Globals.begin(); }
globals_iterator globals_end() const { return Globals.end(); }
/// getNodeFlags - Return all of the flags set on the node. If the DEAD flag
/// is set, hide it from the caller.
unsigned getNodeFlags() const { return NodeType.getFlags() & ~DSFlags::DeadNode; }
void makeNodeDead() {
assert(hasNoReferrers() && "Dead node shouldn't have refs!");
/// forwardNode - Mark this node as being obsolete, and all references to it
/// should be forwarded to the specified node and offset.
void forwardNode(DSNode *To, unsigned Offset);
void print(OStream &O, const DSGraph *G) const {
if ( print(*, G);
void print(std::ostream &O, const DSGraph *G) const;
void dump() const;
void assertOK() const;
void dropAllReferences() {
if (isForwarding())
ForwardNH.setTo(0, 0);
/// remapLinks - Change all of the Links in the current node according to the
/// specified mapping.
void remapLinks(hash_map<const DSNode*, DSNodeHandle> &OldNodeMap);
/// markReachableNodes - This method recursively traverses the specified
/// DSNodes, marking any nodes which are reachable. All reachable nodes it
/// adds to the set, which allows it to only traverse visited nodes once.
void markReachableNodes(hash_set<const DSNode*> &ReachableNodes) const;
friend class DSNodeHandle;
// static mergeNodes - Helper for mergeWith()
static void MergeNodes(DSNodeHandle& CurNodeH, DSNodeHandle& NH);
// Define the ilist_traits specialization for the DSGraph ilist.
struct ilist_traits<DSNode> {
static DSNode *getPrev(const DSNode *N) { return N->Prev; }
static DSNode *getNext(const DSNode *N) { return N->Next; }
static void deleteNode(llvm::DSNode *V) { delete V; }
static void setPrev(DSNode *N, DSNode *Prev) { N->Prev = Prev; }
static void setNext(DSNode *N, DSNode *Next) { N->Next = Next; }
static DSNode *createSentinel() { return new DSNode(0,0); }
static void destroySentinel(DSNode *N) { delete N; }
void addNodeToList(DSNode *NTy) {}
void removeNodeFromList(DSNode *NTy) {}
void transferNodesFromList(iplist<DSNode, ilist_traits> &L2,
ilist_iterator<DSNode> first,
ilist_iterator<DSNode> last) {}
DSNode *provideInitialHead() const {
DSNode * sentinel = createSentinel();
setPrev (sentinel, sentinel);
return sentinel;
/// ensureHead - make sure that Head is either already
/// initialized or assigned a fresh sentinel
/// @return the sentinel
static DSNode *ensureHead(DSNode *&Head) {
if (!Head) {
Head = createSentinel();
noteHead (Head, Head);
setNext(Head, Head);
return Head;
return getPrev(Head);
/// noteHead - stash the sentinel into its default location
static void noteHead(DSNode *NewHead, DSNode *Sentinel) {
setPrev(NewHead, Sentinel);
struct ilist_traits<const DSNode> : public ilist_traits<DSNode> {};
// Define inline DSNodeHandle functions that depend on the definition of DSNode
inline DSNode *DSNodeHandle::getNode() const {
// Disabling this assertion because it is failing on a "magic" struct
// in named (from bind). The fourth field is an array of length 0,
// presumably used to create struct instances of different sizes.
// In a variable length struct, Offset could exceed Size when getNode()
// is called before such a node is folded. In this case, the DS Analysis now
// correctly folds this node after calling getNode.
/* assert((!N ||
N->isNodeCompletelyFolded() ||
(N->Size == 0 && Offset == 0) ||
(int(Offset) >= 0 && Offset < N->Size) ||
(int(Offset) < 0 && -int(Offset) < int(N->Size)) ||
N->isForwarding()) && "Node handle offset out of range!");
if (N == 0 || !N->isForwarding())
return N;
return HandleForwarding();
inline const DSNodeHandle& DSNodeHandle::setTo(DSNode *n, unsigned NewOffset) const {
assert((!n || !n->isForwarding()) && "Cannot set node to a forwarded node!");
if (N) getNode()->NumReferrers--;
N = n;
Offset = NewOffset;
if (N) {
if (Offset >= N->Size) {
assert((Offset == 0 || N->Size == 1) &&
"Pointer to non-collapsed node with invalid offset!");
Offset = 0;
assert(!N || !N->NodeType.isDeadNode());
assert((!N || Offset < N->Size || (N->Size == 0 && Offset == 0) ||
N->isForwarding()) && "Node handle offset out of range!");
return *this;
inline bool DSNodeHandle::hasLink(unsigned Num) const {
assert(N && "DSNodeHandle does not point to a node yet!");
return getNode()->hasLink(Num+Offset);
/// getLink - Treat this current node pointer as a pointer to a structure of
/// some sort. This method will return the pointer a mem[this+Num]
inline const DSNodeHandle &DSNodeHandle::getLink(unsigned Off) const {
assert(N && "DSNodeHandle does not point to a node yet!");
return getNode()->getLink(Offset+Off);
inline DSNodeHandle &DSNodeHandle::getLink(unsigned Off) {
assert(N && "DSNodeHandle does not point to a node yet!");
return getNode()->getLink(Off+Offset);
inline void DSNodeHandle::setLink(unsigned Off, const DSNodeHandle &NH) {
assert(N && "DSNodeHandle does not point to a node yet!");
getNode()->setLink(Off+Offset, NH);
/// addEdgeTo - Add an edge from the current node to the specified node. This
/// can cause merging of nodes in the graph.
inline void DSNodeHandle::addEdgeTo(unsigned Off, const DSNodeHandle &Node) {
assert(N && "DSNodeHandle does not point to a node yet!");
getNode()->addEdgeTo(Off+Offset, Node);
/// mergeWith - Merge the logical node pointed to by 'this' with the node
/// pointed to by 'N'.
inline void DSNodeHandle::mergeWith(const DSNodeHandle &Node) const {
if (!isNull())
getNode()->mergeWith(Node, Offset);
else { // No node to merge with, so just point to Node
Offset = 0;
DSNode *NN = Node.getNode();
setTo(NN, Node.getOffset());
} // End llvm namespace