Checkin the "meat" of the Data structure graph itself. I forgot to check

this in before. :( llvm-svn: 4009
2024-11-25 04:02:41 +01:00 · 2002-10-02 04:58:12 +00:00 · 2002-10-02 04:58:12 +00:00 · 0851fb32b7
commit 0851fb32b7
parent 8c25c1a641
1 changed files with 477 additions and 0 deletions
--- a/include/llvm/Analysis/DSGraph.h
+++ b/include/llvm/Analysis/DSGraph.h
@ -0,0 +1,477 @@
+//===- DSGraph.h - Represent a collection of data structures ----*- C++ -*-===//
+//
+// This header defines the primative classes that make up a data structure
+// graph.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_DSGRAPH_H
+#define LLVM_ANALYSIS_DSGRAPH_H
+
+#include "llvm/Pass.h"
+
+class GlobalValue;
+class Type;
+
+class DSNode;                  // Each node in the graph
+class DSGraph;                 // A graph for a function
+class DSNodeIterator;          // Data structure graph traversal iterator
+
+//===----------------------------------------------------------------------===//
+/// 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+/// graph from getting out of date.  This class represents a "pointer" in the
+/// graph, whose destination is an indexed offset into a node.
+///
+class DSNodeHandle {
+  DSNode *N;
+  unsigned Offset;
+public:
+  // Allow construction, destruction, and assignment...
+  DSNodeHandle(DSNode *n = 0, unsigned offs = 0) : N(0), Offset(offs) {
+    setNode(n);
+  }
+  DSNodeHandle(const DSNodeHandle &H) : N(0), Offset(H.Offset) { setNode(H.N); }
+  ~DSNodeHandle() { setNode((DSNode*)0); }
+  DSNodeHandle &operator=(const DSNodeHandle &H) {
+    setNode(H.N); Offset = H.Offset;
+    return *this;
+  }
+
+  bool operator<(const DSNodeHandle &H) const {  // Allow sorting
+    return N < H.N || (N == H.N && Offset < H.Offset);
+  }
+  bool operator==(const DSNodeHandle &H) const { // Allow comparison
+    return N == H.N && Offset == H.Offset;
+  }
+  bool operator!=(const DSNodeHandle &H) const { return !operator==(H); }
+
+  // Allow explicit conversion to DSNode...
+  DSNode *getNode() const { return N; }
+  unsigned getOffset() const { return Offset; }
+
+  inline void setNode(DSNode *N);  // Defined inline later...
+  void setOffset(unsigned O) { Offset = O; }
+
+  void addEdgeTo(unsigned LinkNo, const DSNodeHandle &N);
+  void addEdgeTo(const DSNodeHandle &N) { addEdgeTo(0, N); }
+
+  /// mergeWith - Merge the logical node pointed to by 'this' with the node
+  /// pointed to by 'N'.
+  ///
+  void mergeWith(const DSNodeHandle &N);
+
+  // hasLink - Return true if there is a link at the specified offset...
+  inline bool hasLink(unsigned Num) const;
+
+  /// 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 *getLink(unsigned Num) const;
+  inline DSNodeHandle *getLink(unsigned Num);
+
+  inline void setLink(unsigned Num, const DSNodeHandle &NH);
+};
+
+
+//===----------------------------------------------------------------------===//
+/// 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 {
+  /// Links - Contains one entry for every _distinct_ pointer field in the
+  /// memory block.  These are demand allocated and indexed by the MergeMap
+  /// vector.
+  ///
+  std::vector<DSNodeHandle> Links;
+
+  /// MergeMap - Maps from every byte in the object to a signed byte number.
+  /// This map is neccesary due to the merging that is possible as part of the
+  /// unification algorithm.  To merge two distinct bytes of the object together
+  /// into a single logical byte, the indexes for the two bytes are set to the
+  /// same value.  This fully general merging is capable of representing all
+  /// manners of array merging if neccesary.
+  ///
+  /// This map is also used to map outgoing pointers to various byte offsets in
+  /// this data structure node.  If this value is >= 0, then it indicates that
+  /// the numbered entry in the Links vector contains the outgoing edge for this
+  /// byte offset.  In this way, the Links vector can be demand allocated and
+  /// byte elements of the node may be merged without needing a Link allocated
+  /// for it.
+  ///
+  /// Initially, each each element of the MergeMap is assigned a unique negative
+  /// number, which are then merged as the unification occurs.
+  ///
+  std::vector<signed char> MergeMap;
+
+  /// Referrers - Keep track of all of the node handles that point to this
+  /// DSNode.  These pointers may need to be updated to point to a different
+  /// node if this node gets merged with it.
+  ///
+  std::vector<DSNodeHandle*> Referrers;
+
+  /// TypeEntries - As part of the merging process of this algorithm, nodes of
+  /// different types can be represented by this single DSNode.  This vector is
+  /// kept sorted.
+  ///
+  typedef std::pair<const Type *, unsigned> TypeRec;
+  std::vector<TypeRec> TypeEntries;
+
+  /// 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,        // 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
+    Incomplete = 1 << 4,   // 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...
+    assert(Referrers.empty() && "Referrers to dead node exist!");
+#endif
+  }
+
+  // Iterator for graph interface...
+  typedef DSNodeIterator iterator;
+  inline iterator begin();   // Defined in DataStructureGraph.h
+  inline iterator end();
+
+  //===--------------------------------------------------
+  // Accessors
+
+  // getSize - Return the maximum number of bytes occupied by this object...
+  unsigned getSize() const { return MergeMap.size(); }
+
+  // getTypeEntries - Return the possible types and their offsets in this object
+  const std::vector<TypeRec> &getTypeEntries() const { return TypeEntries; }
+
+  // getReferrers - Return a list of the pointers to this node...
+  const std::vector<DSNodeHandle*> &getReferrers() const { return Referrers; }
+
+
+  /// hasLink - Return true if this memory object has a link at the specified
+  /// location.
+  ///
+  bool hasLink(unsigned i) const {
+    assert(i < getSize() && "Field Link index is out of range!");
+    return MergeMap[i] >= 0;
+  }
+
+  DSNodeHandle *getLink(unsigned i) {
+    if (hasLink(i))
+      return &Links[MergeMap[i]];
+    return 0;
+  }
+  const DSNodeHandle *getLink(unsigned i) const {
+    if (hasLink(i))
+      return &Links[MergeMap[i]];
+    return 0;
+  }
+
+  /// 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 i, const DSNodeHandle &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(GlobalValue *GV);
+  const std::vector<GlobalValue*> &getGlobals() const { return Globals; }
+  std::vector<GlobalValue*> &getGlobals() { return Globals; }
+
+  void print(std::ostream &O, const DSGraph *G) const;
+  void dump() const;
+
+  void dropAllReferences() {
+    Links.clear();
+  }
+
+  /// remapLinks - Change all of the Links in the current node according to the
+  /// specified mapping.
+  void remapLinks(std::map<const DSNode*, DSNode*> &OldNodeMap);
+
+private:
+  friend class DSNodeHandle;
+  // addReferrer - Keep the referrer set up to date...
+  void addReferrer(DSNodeHandle *H) { Referrers.push_back(H); }
+  void removeReferrer(DSNodeHandle *H);
+
+  /// rewriteMergeMap - Loop over the mergemap, replacing any references to the
+  /// index From to be references to the index To.
+  ///
+  void rewriteMergeMap(signed char From, signed char To) {
+    assert(From != To && "Cannot change something into itself!");
+    for (unsigned i = 0, e = MergeMap.size(); i != e; ++i)
+      if (MergeMap[i] == From)
+        MergeMap[i] = To;
+  }
+
+  /// mergeMappedValues - This is the higher level form of rewriteMergeMap.  It
+  /// is fully capable of merging links together if neccesary as well as simply
+  /// rewriting the map entries.
+  ///
+  void mergeMappedValues(signed char V1, signed char V2);
+};
+
+
+//===----------------------------------------------------------------------===//
+// Define inline DSNodeHandle functions that depend on the definition of DSNode
+//
+
+inline void DSNodeHandle::setNode(DSNode *n) {
+  if (N) N->removeReferrer(this);
+  N = n;
+  if (N) N->addReferrer(this);
+}
+
+inline bool DSNodeHandle::hasLink(unsigned Num) const {
+  assert(N && "DSNodeHandle does not point to a node yet!");
+  return N->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 Num) const {
+  assert(N && "DSNodeHandle does not point to a node yet!");
+  return N->getLink(Num+Offset);
+}
+inline DSNodeHandle *DSNodeHandle::getLink(unsigned Num) {
+  assert(N && "DSNodeHandle does not point to a node yet!");
+  return N->getLink(Num+Offset);
+}
+
+inline void DSNodeHandle::setLink(unsigned Num, const DSNodeHandle &NH) {
+  assert(N && "DSNodeHandle does not point to a node yet!");
+  N->setLink(Num+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 LinkNo, const DSNodeHandle &Node) {
+  assert(N && "DSNodeHandle does not point to a node yet!");
+  N->addEdgeTo(LinkNo+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) {
+  assert(N && "DSNodeHandle does not point to a node yet!");
+  N->mergeWith(Node, Offset);
+}
+
+
+//===----------------------------------------------------------------------===//
+/// 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;
+
+#if 0
+  // GlobalsGraph -- Reference to the common graph of globally visible objects.
+  // This includes GlobalValues, New nodes, Cast nodes, and Calls.
+  // 
+  GlobalDSGraph* GlobalsGraph;
+#endif
+
+  // 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;
+
+#if 0
+  // OrigFunctionCalls - This vector retains a copy of the original function
+  // calls of the current graph.  This is needed to support top-down inlining
+  // after bottom-up inlining is complete, since the latter deletes call nodes.
+  // 
+  std::vector<std::vector<DSNodeHandle> > OrigFunctionCalls;
+
+  // PendingCallers - This vector records all unresolved callers of the
+  // current function, i.e., ones whose graphs have not been inlined into
+  // the current graph.  As long as there are unresolved callers, the nodes
+  // for formal arguments in the current graph cannot be eliminated, and
+  // nodes in the graph reachable from the formal argument nodes or
+  // global variable nodes must be considered incomplete. 
+  std::set<Function*> PendingCallers;
+#endif
+  
+protected:
+
+#if 0
+  // clone all the call nodes and save the copies in OrigFunctionCalls
+  void saveOrigFunctionCalls() {
+    assert(OrigFunctionCalls.size() == 0 && "Do this only once!");
+    OrigFunctionCalls = FunctionCalls;
+  }
+
+  // get the saved copies of the original function call nodes
+  std::vector<std::vector<DSNodeHandle> > &getOrigFunctionCalls() {
+    return OrigFunctionCalls;
+  }
+#endif
+
+  void operator=(const DSGraph &); // DO NOT IMPLEMENT
+public:
+  DSGraph() : Func(0) {}           // Create a new, empty, DSGraph.
+  DSGraph(Function &F);            // Compute the local DSGraph
+  DSGraph(const DSGraph &DSG);     // Copy ctor
+  ~DSGraph();
+
+  bool hasFunction() const { return Func != 0; }
+  Function &getFunction() const { return *Func; }
+
+  /// getNodes - Get a vector of all the nodes in the graph
+  /// 
+  const std::vector<DSNode*> &getNodes() const { return Nodes; }
+        std::vector<DSNode*> &getNodes()       { return Nodes; }
+
+  /// addNode - Add a new node to the graph.
+  ///
+  void addNode(DSNode *N) { Nodes.push_back(N); }
+
+  /// getValueMap - Get a map that describes what the nodes the scalars in this
+  /// function point to...
+  ///
+  std::map<Value*, DSNodeHandle> &getValueMap() { return ValueMap; }
+  const std::map<Value*, DSNodeHandle> &getValueMap() const { return ValueMap;}
+
+  std::vector<std::vector<DSNodeHandle> > &getFunctionCalls() {
+    return FunctionCalls;
+  }
+  const std::vector<std::vector<DSNodeHandle> > &getFunctionCalls() const {
+    return FunctionCalls;
+  }
+
+  const DSNodeHandle &getRetNode() const { return RetNode; }
+        DSNodeHandle &getRetNode()       { return RetNode; }
+
+  unsigned getGraphSize() const {
+    return Nodes.size();
+  }
+
+  void print(std::ostream &O) const;
+  void dump() const;
+  void writeGraphToFile(std::ostream &O, const std::string &GraphName);
+
+  // maskNodeTypes - Apply a mask to all of the node types in the graph.  This
+  // is useful for clearing out markers like Scalar or Incomplete.
+  //
+  void maskNodeTypes(unsigned char Mask);
+  void maskIncompleteMarkers() { maskNodeTypes(~DSNode::Incomplete); }
+
+  // markIncompleteNodes - Traverse the graph, identifying nodes that may be
+  // modified by other functions that have not been resolved yet.  This marks
+  // nodes that are reachable through three sources of "unknownness":
+  //   Global Variables, Function Calls, and Incoming Arguments
+  //
+  // For any node that may have unknown components (because something outside
+  // the scope of current analysis may have modified it), the 'Incomplete' flag
+  // is added to the NodeType.
+  //
+  void markIncompleteNodes(bool markFormalArgs = true);
+
+  // removeTriviallyDeadNodes - After the graph has been constructed, this
+  // method removes all unreachable nodes that are created because they got
+  // merged with other nodes in the graph.
+  //
+  void removeTriviallyDeadNodes(bool KeepAllGlobals = false);
+
+  // removeDeadNodes - Use a more powerful reachability analysis to eliminate
+  // subgraphs that are unreachable.  This often occurs because the data
+  // structure doesn't "escape" into it's caller, and thus should be eliminated
+  // from the caller's graph entirely.  This is only appropriate to use when
+  // inlining graphs.
+  //
+  void removeDeadNodes(bool KeepAllGlobals = false, bool KeepCalls = true);
+
+#if 0
+  // AddCaller - add a known caller node into the graph and mark it pending.
+  // getCallers - get a vector of the functions that call this one
+  // getCallersPending - get a matching vector of bools indicating if each
+  //                     caller's DSGraph has been resolved into this one.
+  // 
+  void addCaller(Function &caller) {
+    PendingCallers.insert(&caller);
+  }
+  std::set<Function*> &getPendingCallers() {
+    return PendingCallers;
+  }
+#endif
+
+  // cloneInto - Clone the specified DSGraph into the current graph, returning
+  // the Return node of the graph.  The translated ValueMap for the old function
+  // is filled into the OldValMap member.
+  // If StripScalars (StripAllocas) is set to true, Scalar (Alloca) markers
+  // are removed from the graph as the graph is being cloned.
+  // If CopyCallers is set to true, the PendingCallers list is copied.
+  // If CopyOrigCalls is set to true, the OrigFunctionCalls list is copied.
+  //
+  DSNodeHandle cloneInto(const DSGraph &G,
+                         std::map<Value*, DSNodeHandle> &OldValMap,
+                         std::map<const DSNode*, DSNode*> &OldNodeMap,
+                         bool StripScalars = false, bool StripAllocas = false,
+                         bool CopyCallers = true, bool CopyOrigCalls = true);
+
+#if 0
+  // cloneGlobalInto - Clone the given global node (or the node for the given
+  // GlobalValue) from the GlobalsGraph and all its target links (recursively).
+  // 
+  DSNode* cloneGlobalInto(const DSNode* GNode);
+  DSNode* cloneGlobalInto(GlobalValue* GV) {
+    assert(!GV || (((DSGraph*) GlobalsGraph)->ValueMap[GV] != 0));
+    return GV? cloneGlobalInto(((DSGraph*) GlobalsGraph)->ValueMap[GV]) : 0;
+  }
+#endif
+
+private:
+  bool isNodeDead(DSNode *N);
+};
+
+#endif