path: root/include/llvm/Analysis/DataStructure.h

//===- DataStructure.h - Build data structure graphs -------------*- C++ -*--=//
//
// Implement the LLVM data structure analysis library.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_ANALYSIS_DATA_STRUCTURE_H
#define LLVM_ANALYSIS_DATA_STRUCTURE_H

#include "llvm/Pass.h"
#include <string>

class Type;
class GlobalValue;
class DSNode;                  // Each node in the graph
class DSGraph;                 // A graph for a function
class DSNodeIterator;          // Data structure graph traversal iterator
class LocalDataStructures;     // A collection of local graphs for a program
class BUDataStructures;        // A collection of bu graphs for a program
class TDDataStructures;        // A collection of td graphs for a program

//===----------------------------------------------------------------------===//
// DSNodeHandle - Implement a "handle" to a data structure node that takes care
// of all of the add/un'refing of the node to prevent the backpointers in the
// graph from getting out of date.
//
class DSNodeHandle {
  DSNode *N;
public:
  // Allow construction, destruction, and assignment...
  DSNodeHandle(DSNode *n = 0) : N(0) { operator=(n); }
  DSNodeHandle(const DSNodeHandle &H) : N(0) { operator=(H.N); }
  ~DSNodeHandle() { operator=(0); }
  DSNodeHandle &operator=(const DSNodeHandle &H) {operator=(H.N); return *this;}

  // Assignment of DSNode*, implement all of the add/un'refing (defined later)
  inline DSNodeHandle &operator=(DSNode *n);

  // Allow automatic, implicit, conversion to DSNode*
  operator DSNode*() { return N; }
  operator const DSNode*() const { return N; }
  operator bool() const { return N != 0; }
  operator bool() { return N != 0; }

  bool operator<(const DSNodeHandle &H) const {  // Allow sorting
    return N < H.N;
  }
  bool operator==(const DSNodeHandle &H) const { return N == H.N; }
  bool operator!=(const DSNodeHandle &H) const { return N != H.N; }
  bool operator==(const DSNode *Node) const { return N == Node; }
  bool operator!=(const DSNode *Node) const { return N != Node; }
  bool operator==(DSNode *Node) const { return N == Node; }
  bool operator!=(DSNode *Node) const { return N != Node; }

  // Avoid having comparisons to null cause errors...
  bool operator==(int X) const {
    assert(X == 0 && "Bad comparison!");
    return operator==((DSNode*)0);
  }
  bool operator!=(int X) const { return !operator==(X); }

  // Allow explicit conversion to DSNode...
  DSNode *get() { return N; }
  const DSNode *get() const { return N; }

  // Allow this to be treated like a pointer...
  DSNode *operator->() { return N; }
  const DSNode *operator->() const { return N; }
};


//===----------------------------------------------------------------------===//
// DSNode - Data structure node class
//
// This class keeps track of a node's type, and the fields in the data
// structure.
//
//
class DSNode {
  const Type *Ty;
  std::vector<DSNodeHandle> Links;
  std::vector<DSNodeHandle*> Referrers;

  // Globals - The list of global values that are merged into this node.
  std::vector<GlobalValue*> Globals;

  void operator=(const DSNode &); // DO NOT IMPLEMENT
public:
  enum NodeTy {
    ShadowNode = 0 << 0,   // Nothing is known about this node...
    ScalarNode = 1 << 0,   // Scalar of the current function contains this value
    AllocaNode = 1 << 1,   // This node was allocated with alloca
    NewNode    = 1 << 2,   // This node was allocated with malloc
    GlobalNode = 1 << 3,   // This node was allocated by a global var decl
    SubElement = 1 << 4,   // This node is a part of some other node
    CastNode   = 1 << 5,   // This node is accessed in unsafe ways
    Incomplete = 1 << 6,   // This node may not be complete
  };

  // NodeType - A union of the above bits.  "Shadow" nodes do not add any flags
  // to the nodes in the data structure graph, so it is possible to have nodes
  // with a value of 0 for their NodeType.  Scalar and Alloca markers go away
  // when function graphs are inlined.
  //
  unsigned char NodeType;

  DSNode(enum NodeTy NT, const Type *T);
  DSNode(const DSNode &);

  ~DSNode() {
#ifndef NDEBUG
    dropAllReferences();  // Only needed to satisfy assertion checks...
#endif
    assert(Referrers.empty() && "Referrers to dead node exist!");
  }

  // Iterator for graph interface...
  typedef DSNodeIterator iterator;
  inline iterator begin();   // Defined in DataStructureGraph.h
  inline iterator end();

  // Accessors
  const Type *getType() const { return Ty; }

  unsigned getNumLinks() const { return Links.size(); }
  DSNode *getLink(unsigned i) {
    assert(i < getNumLinks() && "Field links access out of range...");
    return Links[i];
  }
  const DSNode *getLink(unsigned i) const {
    assert(i < getNumLinks() && "Field links access out of range...");
    return Links[i];
  }

  void setLink(unsigned i, DSNode *N) {
    assert(i < getNumLinks() && "Field links access out of range...");
    Links[i] = N;
  }

  // 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(GlobalValue *GV);
  const std::vector<GlobalValue*> &getGlobals() const { return Globals; }
  std::vector<GlobalValue*> &getGlobals() { return Globals; }

  // addEdgeTo - Add an edge from the current node to the specified node.  This
  // can cause merging of nodes in the graph.
  //
  void addEdgeTo(unsigned LinkNo, DSNode *N);
  void addEdgeTo(DSNode *N) {
    assert(getNumLinks() == 1 && "Must specify a field number to add edge if "
           " more than one field exists!");
    addEdgeTo(0, N);
  }

  // mergeWith - Merge this node into the specified node, moving all links to
  // and from the argument node into the current node.  The specified node may
  // be a null pointer (in which case, nothing happens).
  //
  void mergeWith(DSNode *N);

  // addReferrer - Keep the referrer set up to date...
  void addReferrer(DSNodeHandle *H) { Referrers.push_back(H); }
  void removeReferrer(DSNodeHandle *H);
  const std::vector<DSNodeHandle*> &getReferrers() const { return Referrers; }

  void print(std::ostream &O, const DSGraph *G) const;
  void dump() const;

  std::string getCaption(const DSGraph *G) const;

  void dropAllReferences() {
    Links.clear();
  }
};


inline DSNodeHandle &DSNodeHandle::operator=(DSNode *n) {
  if (N) N->removeReferrer(this);
  N = n;
  if (N) N->addReferrer(this);
  return *this;
}


// DSGraph - The graph that represents a function.
//
class DSGraph {
  Function &Func;
  std::vector<DSNode*> Nodes;
  DSNodeHandle RetNode;               // Node that gets returned...
  std::map<Value*, DSNodeHandle> ValueMap;

  // FunctionCalls - This vector maintains a single entry for each call
  // instruction in the current graph.  Each call entry contains DSNodeHandles
  // that refer to the arguments that are passed into the function call.  The
  // first entry in the vector is the scalar that holds the return value for the
  // call, the second is the function scalar being invoked, and the rest are
  // pointer arguments to the function.
  //
  std::vector<std::vector<DSNodeHandle> > FunctionCalls;

  // OrigFunctionCal