Move PgmDependenceGraph.h out of the public include hierarchy

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14446 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 304 insertions, 2 deletions

diff --git a/lib/Analysis/DataStructure/Parallelize.cpp b/lib/Analysis/DataStructure/Parallelize.cpp
index 46bb72f836..ccc16e3d48 100644
--- a/lib/Analysis/DataStructure/Parallelize.cpp
+++ b/lib/Analysis/DataStructure/Parallelize.cpp
@@ -41,7 +41,7 @@
 #include "llvm/DerivedTypes.h"
 #include "llvm/Instructions.h"
 #include "llvm/Module.h"
-#include "llvm/Analysis/PgmDependenceGraph.h"
+#include "PgmDependenceGraph.h"
 #include "llvm/Analysis/DataStructure.h"
 #include "llvm/Analysis/DSGraph.h"
 #include "llvm/Support/InstVisitor.h"
diff --git a/lib/Analysis/DataStructure/PgmDependenceGraph.cpp b/lib/Analysis/DataStructure/PgmDependenceGraph.cpp
index b861c89947..b52848118c 100644
--- a/lib/Analysis/DataStructure/PgmDependenceGraph.cpp
+++ b/lib/Analysis/DataStructure/PgmDependenceGraph.cpp
@@ -25,7 +25,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/Analysis/PgmDependenceGraph.h"
+#include "PgmDependenceGraph.h"
 #include "llvm/Analysis/MemoryDepAnalysis.h"
 #include "llvm/Analysis/PostDominators.h"
 #include "llvm/Function.h"
diff --git a/lib/Analysis/DataStructure/PgmDependenceGraph.h b/lib/Analysis/DataStructure/PgmDependenceGraph.h
new file mode 100644
index 0000000000..0ed0ba81ae
--- /dev/null
+++ b/lib/Analysis/DataStructure/PgmDependenceGraph.h
@@ -0,0 +1,302 @@
+//===- PgmDependenceGraph.h - Enumerate the PDG for a function --*- 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.
+// 
+//===----------------------------------------------------------------------===//
+// 
+// The Program Dependence Graph (PDG) for a single function represents all
+// data and control dependences for the function.  This file provides an
+// iterator to enumerate all these dependences.  In particular, it enumerates:
+// 
+// -- Data dependences on memory locations, computed using the
+//    MemoryDepAnalysis pass;
+// -- Data dependences on SSA registers, directly from Def-Use edges of Values;
+// -- Control dependences, computed using postdominance frontiers
+//    (NOT YET IMPLEMENTED).
+// 
+// Note that this file does not create an explicit dependence graph --
+// it only provides an iterator to traverse the PDG conceptually.
+// The MemoryDepAnalysis does build an explicit graph, which is used internally
+// here.  That graph could be augmented with the other dependences above if
+// desired, but for most uses there will be little need to do that.
+// 
+// Key Classes:
+// 
+// enum PDGIteratorFlags -- Specify which dependences to enumerate.
+// 
+// class PDGIterator     -- The PDG iterator.  This is essentially like a
+//                          pointer to class Dependence, but doesn't explicitly
+//                          construct a Dependence object for each dependence.
+//
+// class PgmDependenceGraph -- Interface to obtain PDGIterators for each
+//                          instruction.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_PGMDEPENDENCEGRAPH_H
+#define LLVM_ANALYSIS_PGMDEPENDENCEGRAPH_H
+
+#include "llvm/Analysis/DependenceGraph.h"
+#include "llvm/Analysis/MemoryDepAnalysis.h"
+/* #include "llvm/Analysis/PostDominators.h" -- see below */
+#include "llvm/Instruction.h"
+#include "llvm/Pass.h"
+#include "Support/iterator"
+
+namespace llvm {
+
+class DSGraph;
+class DependenceGraph;
+class PgmDependenceGraph;
+
+//---------------------------------------------------------------------------
+/// enum PDGIteratorFlags - specify which dependences incident on a statement
+/// are to be enumerated: Memory deps, SSA deps, Control deps, or any
+/// combination thereof.
+///
+enum PDGIteratorFlags {
+  MemoryDeps  = 0x1,                                 // load/store/call deps
+  SSADeps     = 0x2,                                 // SSA deps (true)
+  ControlDeps = /* 0x4*/ 0x0,                        // control dependences
+  AllDataDeps = MemoryDeps | SSADeps,                // shorthand for data deps
+  AllDeps     = MemoryDeps | SSADeps | ControlDeps   // shorthand for all three
+};
+
+//---------------------------------------------------------------------------
+/// struct DepIterState - an internal implementation detail.
+/// It are exposed here only to give inlinable access to field dep,
+/// which is the representation for the current dependence pointed to by
+/// a PgmDependenceGraph::iterator.
+///
+class DepIterState {
+private:
+  typedef char IterStateFlags;
+  static const IterStateFlags NoFlag, MemDone, SSADone, AllDone, FirstTimeFlag;
+
+public:
+  DepGraphNode*              depNode;        // the node being enumerated
+  DependenceGraph::iterator  memDepIter;     // pointer to current memory dep
+  Instruction::op_iterator   ssaInEdgeIter;  // pointer to current SSA in-dep
+  Value::use_iterator        ssaOutEdgeIter; // pointer to current SSA out-dep
+  DependenceGraph*           memDepGraph;    // the core dependence graph
+  Dependence                 dep;            // the "current" dependence
+  PDGIteratorFlags           depFlags:8;     // which deps are we enumerating?
+  IterStateFlags             iterFlags:8;    // marking where the iter stands
+
+  DepIterState(DependenceGraph* _memDepGraph,
+               Instruction&     I, 
+               bool             incomingDeps,
+               PDGIteratorFlags whichDeps);
+
+  bool operator==(const DepIterState& S) {
+    assert(memDepGraph == S.memDepGraph &&
+           "Incompatible iterators! This is a probable sign of something BAD.");
+    return (iterFlags == S.iterFlags &&
+            dep == S.dep && depFlags == S.depFlags && depNode == S.depNode &&
+            memDepIter == S.memDepIter && ssaInEdgeIter == S.ssaInEdgeIter &&
+            ssaOutEdgeIter == S.ssaOutEdgeIter);
+  }
+
+  // Is the iteration completely done?
+  // 
+  bool done() const { return iterFlags & AllDone; }
+
+  /// Next - Bump this iterator logically by 1 (to next dependence) and reset
+  /// the dep field to represent the new dependence if there is one.
+  /// Set done = true otherwise.
+  /// 
+  void Next();
+
+  /// SetFirstMemoryDep - Find the first memory dependence for the current Mem
+  /// In/Out iterators. Sets dep to that dependence and returns true if one is
+  /// found. Returns false and leaves dep unchanged otherwise.
+  /// 
+  bool SetFirstMemoryDep();
+
+  /// SetFirstSSADep - Find the next valid data dependence for the current SSA
+  /// In/Out iterators. A valid data dependence is one that is to/from an
+  /// Instruction. E.g., an SSA edge from a formal parameter is not a valid
+  /// dependence. Sets dep to that dependence and returns true if a valid one is
+  /// found. Returns false and leaves dep unchanged otherwise.
+  ///
+  bool SetFirstSSADep();
+};
+
+
+//---------------------------------------------------------------------------
+/// PDGIterator Class - represents a pointer to a single dependence in the
+/// program dependence graph.  It is essentially like a pointer to an object of
+/// class Dependence but it is much more efficient to retrieve information about
+/// the dependence directly rather than constructing the equivalent Dependence
+/// object (since that object is normally not constructed for SSA def-use
+/// dependences).
+///
+class PDGIterator: public forward_iterator<Dependence, ptrdiff_t> {
+  DepIterState* istate;
+
+#if 0
+  /*copy*/     PDGIterator    (const PDGIterator& I);   // do not implement!
+  PDGIterator& operator=      (const PDGIterator& I);   // do not implement!
+
+  /*copy*/     PDGIterator    (PDGIterator& I) : istate(I.istate) {
+    I.istate = NULL;                  // ensure this is not deleted twice.
+  }
+#endif
+
+  friend class PgmDependenceGraph;
+
+public:
+  typedef PDGIterator _Self;
+
+  PDGIterator(DepIterState* _istate) : istate(_istate) {}
+  ~PDGIterator() { delete istate; }
+
+  PDGIterator(const PDGIterator& I) :istate(new DepIterState(*I.istate)) {}
+
+  PDGIterator& operator=(const PDGIterator& I) {
+    if (istate) delete istate;
+    istate = new DepIterState(*I.istate);
+    return *this;
+  }
+
+  /// fini - check if the iteration is complete
+  /// 
+  bool fini() const { return !istate || istate->done(); }
+
+  // Retrieve the underlying Dependence.  Returns NULL if fini().
+  // 
+  Dependence* operator*()  const { return fini() ?  NULL : &istate->dep; }
+  Dependence* operator->() const { assert(!fini()); return &istate->dep; }
+
+  // Increment the iterator
+  // 
+  _Self& operator++() { if (!fini()) istate->Next(); return *this;}
+  _Self& operator++(int);   // do not implement!
+
+  // Equality comparison: a "null" state should compare equal to done
+  // This is efficient for comparing with "end" or with itself, but could
+  // be quite inefficient for other cases.
+  // 
+  bool operator==(const PDGIterator& I) const {
+    if (I.istate == NULL)               // most common case: iter == end()
+      return (istate == NULL || istate->done());
+    if (istate == NULL)
+      return (I.istate == NULL || I.istate->done());
+    return (*istate == *I.istate);
+  }
+  bool operator!=(const PDGIterator& I) const {
+    return ! (*this == I);
+  }
+};
+
+
+///---------------------------------------------------------------------------
+/// class PgmDependenceGraph:
+///
+/// This pass enumerates dependences incident on each instruction in a function.
+/// It can be made a FunctionPass once a Pass (such as Parallelize) is
+/// allowed to use a FunctionPass such as this one.
+///---------------------------------------------------------------------------
+
+class PgmDependenceGraph: public Pass {
+
+  /// Information about the function being analyzed.
+  /// 
+  DependenceGraph* memDepGraph;
+  
+  // print helper function.
+  void printOutgoingSSADeps(Instruction& I, std::ostream &O);
+
+  /// MakeIterator - creates and initializes an iterator as specified.
+  ///
+  PDGIterator   MakeIterator(Instruction&     I,
+                             bool             incomingDeps,
+                             PDGIteratorFlags whichDeps);
+  
+  /// MakeIterator - creates a null iterator representing end-of-iteration.
+  /// 
+  PDGIterator  MakeIterator() { return PDGIterator(NULL); }
+
+  friend class PDGIterator;
+  friend class DepIterState;
+
+public:
+  typedef PDGIterator iterator;
+  /* typedef PDGIterator<const Dependence> const iterator; */
+
+public:
+  PgmDependenceGraph() : memDepGraph(NULL) {}
+  ~PgmDependenceGraph() {}
+
+  /// Iterators to enumerate the program dependence graph for a function.
+  /// Note that this does not provide "end" iterators to check for completion.
+  /// Instead, just use iterator::fini() or iterator::operator*() == NULL
+  ///
+  iterator  inDepBegin(Instruction& I, PDGIteratorFlags whichDeps = AllDeps) {
+    return MakeIterator(I, /*inDeps*/ true, whichDeps);
+  }
+  iterator  inDepEnd  (Instruction& I, PDGIteratorFlags whichDeps = AllDeps) {
+    return MakeIterator();
+  }
+  iterator  outDepBegin(Instruction& I, PDGIteratorFlags whichDeps = AllDeps) {
+    return MakeIterator(I, /*inDeps*/ false, whichDeps);
+  }
+  iterator  outDepEnd  (Instruction& I, PDGIteratorFlags whichDeps = AllDeps) {
+    return MakeIterator();
+  }
+
+  //------------------------------------------------------------------------
+  /// TEMPORARY FUNCTIONS TO MAKE THIS A MODULE PASS ---
+  /// These functions will go away once this class becomes a FunctionPass.
+
+  /// Driver function to compute dependence graphs for every function.
+  /// 
+  bool run(Module& M) { return true; }
+
+  /// getGraph() -- Retrieve the pgm dependence graph for a function.
+  /// This is temporary and will go away once this is a FunctionPass.
+  /// At that point, this class itself will be the PgmDependenceGraph you want.
+  /// 
+  PgmDependenceGraph& getGraph(Function& F) {
+    Visiting(F);
+    return *this;
+  }
+
+  private:
+  void Visiting(Function& F) {
+    memDepGraph = &getAnalysis<MemoryDepAnalysis>().getGraph(F);
+  }
+  public:
+  ///----END TEMPORARY FUNCTIONS---------------------------------------------
+
+
+  /// This initializes the program dependence graph iterator for a function.
+  /// 
+  bool runOnFunction(Function& func) {
+    Visiting(func);
+    return true;
+  }
+
+  /// getAnalysisUsage - This does not modify anything.
+  /// It uses the Memory Dependence Analysis pass.
+  /// It needs to use the PostDominanceFrontier pass, but cannot because
+  /// that is a FunctionPass.  This means control dependence are not emumerated.
+  ///
+  void getAnalysisUsage(AnalysisUsage &AU) const {
+    AU.setPreservesAll();
+    AU.addRequired<MemoryDepAnalysis>();
+    /* AU.addRequired<PostDominanceFrontier>(); */
+  }
+
+  /// Debugging support methods
+  /// 
+  void print(std::ostream &O) const;
+  void dump() const;
+};
+
+} // End llvm namespace
+
+#endif