Implementation of path profiling.

Modified patch by Adam Preuss.

This builds on the existing framework for block tracing, edge profiling and optimal edge profiling.
See -help-hidden for new flags.
For documentation, see the technical report "Implementation of Path Profiling..." in llvm.org/pubs.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124515 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Analysis/Passes.h

@@ -114,6 +114,28 @@ namespace llvm {
   //
   FunctionPass *createProfileVerifierPass();
 
+  //===--------------------------------------------------------------------===//
+  //
+  // createPathProfileLoaderPass - This pass loads information from a path
+  // profile dump file.
+  //
+  ModulePass *createPathProfileLoaderPass();
+  extern char &PathProfileLoaderPassID;
+
+  //===--------------------------------------------------------------------===//
+  //
+  // createNoPathProfileInfoPass - This pass implements the default
+  // "no path profile".
+  //
+  ImmutablePass *createNoPathProfileInfoPass();
+
+  //===--------------------------------------------------------------------===//
+  //
+  // createPathProfileVerifierPass - This pass verifies path profiling
+  // information.
+  //
+  ModulePass *createPathProfileVerifierPass();
+
   //===--------------------------------------------------------------------===//
   //
   // createDSAAPass - This pass implements simple context sensitive alias
@@ -140,7 +162,7 @@ namespace llvm {
   // createLiveValuesPass - This creates an instance of the LiveValues pass.
   //
   FunctionPass *createLiveValuesPass();
-  
+
   //===--------------------------------------------------------------------===//
   //
   /// createLazyValueInfoPass - This creates an instance of the LazyValueInfo
@@ -153,7 +175,7 @@ namespace llvm {
   // LoopDependenceAnalysis pass.
   //
   LoopPass *createLoopDependenceAnalysisPass();
-  
+
   // Minor pass prototypes, allowing us to expose them through bugpoint and
   // analyze.
   FunctionPass *createInstCountPass();

include/llvm/Analysis/PathNumbering.h

@@ -0,0 +1,304 @@
+//===- PathNumbering.h ----------------------------------------*- C++ -*---===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Ball-Larus path numbers uniquely identify paths through a directed acyclic
+// graph (DAG) [Ball96].  For a CFG backedges are removed and replaced by phony
+// edges to obtain a DAG, and thus the unique path numbers [Ball96].
+//
+// The purpose of this analysis is to enumerate the edges in a CFG in order
+// to obtain paths from path numbers in a convenient manner.  As described in
+// [Ball96] edges can be enumerated such that given a path number by following
+// the CFG and updating the path number, the path is obtained.
+//
+// [Ball96]
+//  T. Ball and J. R. Larus. "Efficient Path Profiling."
+//  International Symposium on Microarchitecture, pages 46-57, 1996.
+//  http://portal.acm.org/citation.cfm?id=243857
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_PATH_NUMBERING_H
+#define LLVM_PATH_NUMBERING_H
+
+#include "llvm/BasicBlock.h"
+#include "llvm/Instructions.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/CFG.h"
+#include "llvm/Analysis/ProfileInfoTypes.h"
+#include <map>
+#include <stack>
+#include <vector>
+
+namespace llvm {
+class BallLarusNode;
+class BallLarusEdge;
+class BallLarusDag;
+
+// typedefs for storage/ interators of various DAG components
+typedef std::vector<BallLarusNode*> BLNodeVector;
+typedef std::vector<BallLarusNode*>::iterator BLNodeIterator;
+typedef std::vector<BallLarusEdge*> BLEdgeVector;
+typedef std::vector<BallLarusEdge*>::iterator BLEdgeIterator;
+typedef std::map<BasicBlock*, BallLarusNode*> BLBlockNodeMap;
+typedef std::stack<BallLarusNode*> BLNodeStack;
+
+// Represents a basic block with information necessary for the BallLarus
+// algorithms.
+class BallLarusNode {
+public:
+  enum NodeColor { WHITE, GRAY, BLACK };
+
+  // Constructor: Initializes a new Node for the given BasicBlock
+  BallLarusNode(BasicBlock* BB) :
+    _basicBlock(BB), _numberPaths(0), _color(WHITE) {
+    static unsigned nextUID = 0;
+    _uid = nextUID++;
+  }
+
+  // Returns the basic block for the BallLarusNode
+  BasicBlock* getBlock();
+
+  // Get/set the number of paths to the exit starting at the node.
+  unsigned getNumberPaths();
+  void setNumberPaths(unsigned numberPaths);
+
+  // Get/set the NodeColor used in graph algorithms.
+  NodeColor getColor();
+  void setColor(NodeColor color);
+
+  // Iterator information for predecessor edges. Includes phony and
+  // backedges.
+  BLEdgeIterator predBegin();
+  BLEdgeIterator predEnd();
+  unsigned getNumberPredEdges();
+
+  // Iterator information for successor edges. Includes phony and
+  // backedges.
+  BLEdgeIterator succBegin();
+  BLEdgeIterator succEnd();
+  unsigned getNumberSuccEdges();
+
+  // Add an edge to the predecessor list.
+  void addPredEdge(BallLarusEdge* edge);
+
+  // Remove an edge from the predecessor list.
+  void removePredEdge(BallLarusEdge* edge);
+
+  // Add an edge to the successor list.
+  void addSuccEdge(BallLarusEdge* edge);
+
+  // Remove an edge from the successor list.
+  void removeSuccEdge(BallLarusEdge* edge);
+
+  // Returns the name of the BasicBlock being represented.  If BasicBlock
+  // is null then returns "<null>".  If BasicBlock has no name, then
+  // "<unnamed>" is returned.  Intended for use with debug output.
+  std::string getName();
+
+private:
+  // The corresponding underlying BB.
+  BasicBlock* _basicBlock;
+
+  // Holds the predecessor edges of this node.
+  BLEdgeVector _predEdges;
+
+  // Holds the successor edges of this node.
+  BLEdgeVector _succEdges;
+
+  // The number of paths from the node to the exit.
+  unsigned _numberPaths;
+
+  // 'Color' used by graph algorithms to mark the node.
+  NodeColor _color;
+
+  // Unique ID to ensure naming difference with dotgraphs
+  unsigned _uid;
+
+  // Removes an edge from an edgeVector.  Used by removePredEdge and
+  // removeSuccEdge.
+  void removeEdge(BLEdgeVector& v, BallLarusEdge* e);
+};
+
+// Represents an edge in the Dag.  For an edge, v -> w, v is the source, and
+// w is the target.
+class BallLarusEdge {
+public:
+  enum EdgeType { NORMAL, BACKEDGE, SPLITEDGE,
+    BACKEDGE_PHONY, SPLITEDGE_PHONY, CALLEDGE_PHONY };
+
+  // Constructor: Initializes an BallLarusEdge with a source and target.
+  BallLarusEdge(BallLarusNode* source, BallLarusNode* target,
+                                unsigned duplicateNumber)
+    : _source(source), _target(target), _weight(0), _edgeType(NORMAL),
+      _realEdge(NULL), _duplicateNumber(duplicateNumber) {}
+
+  // Returns the source/ target node of this edge.
+  BallLarusNode* getSource() const;
+  BallLarusNode* getTarget() const;
+
+  // Sets the type of the edge.
+  EdgeType getType() const;
+
+  // Gets the type of the edge.
+  void setType(EdgeType type);
+
+  // Returns the weight of this edge.  Used to decode path numbers to
+  // sequences of basic blocks.
+  unsigned getWeight();
+
+  // Sets the weight of the edge.  Used during path numbering.
+  void setWeight(unsigned weight);
+
+  // Gets/sets the phony edge originating at the root.
+  BallLarusEdge* getPhonyRoot();
+  void setPhonyRoot(BallLarusEdge* phonyRoot);
+
+  // Gets/sets the phony edge terminating at the exit.
+  BallLarusEdge* getPhonyExit();
+  void setPhonyExit(BallLarusEdge* phonyExit);
+
+  // Gets/sets the associated real edge if this is a phony edge.
+  BallLarusEdge* getRealEdge();
+  void setRealEdge(BallLarusEdge* realEdge);
+
+  // Returns the duplicate number of the edge.
+  unsigned getDuplicateNumber();
+
+protected:
+  // Source node for this edge.
+  BallLarusNode* _source;
+
+  // Target node for this edge.
+  BallLarusNode* _target;
+
+private:
+  // Edge weight cooresponding to path number increments before removing
+  // increments along a spanning tree. The sum over the edge weights gives
+  // the path number.
+  unsigned _weight;
+
+  // Type to represent for what this edge is intended
+  EdgeType _edgeType;
+
+  // For backedges and split-edges, the phony edge which is linked to the
+  // root node of the DAG. This contains a path number initialization.
+  BallLarusEdge* _phonyRoot;
+
+  // For backedges and split-edges, the phony edge which is linked to the
+  // exit node of the DAG. This contains a path counter increment, and
+  // potentially a path number increment.
+  BallLarusEdge* _phonyExit;
+
+  // If this is a phony edge, _realEdge is a link to the back or split
+  // edge. Otherwise, this is null.
+  BallLarusEdge* _realEdge;
+
+  // An ID to differentiate between those edges which have the same source
+  // and destination blocks.
+  unsigned _duplicateNumber;
+};
+
+// Represents the Ball Larus DAG for a given Function.  Can calculate
+// various properties required for instrumentation or analysis.  E.g. the
+// edge weights that determine the path number.
+class BallLarusDag {
+public:
+  // Initializes a BallLarusDag from the CFG of a given function.  Must
+  // call init() after creation, since some initialization requires
+  // virtual functions.
+  BallLarusDag(Function &F)
+    : _root(NULL), _exit(NULL), _function(F) {}
+
+  // Initialization that requires virtual functions which are not fully
+  // functional in the constructor.
+  void init();
+
+  // Frees all memory associated with the DAG.
+  virtual ~BallLarusDag();
+
+  // Calculate the path numbers by assigning edge increments as prescribed
+  // in Ball-Larus path profiling.
+  void calculatePathNumbers();
+
+  // Returns the number of paths for the DAG.
+  unsigned getNumberOfPaths();
+
+  // Returns the root (i.e. entry) node for the DAG.
+  BallLarusNode* getRoot();
+
+  // Returns the exit node for the DAG.
+  BallLarusNode* getExit();
+
+  // Returns the function for the DAG.
+  Function& getFunction();
+
+  // Clears the node colors.
+  void clearColors(BallLarusNode::NodeColor color);
+
+protected:
+  // All nodes in the DAG.
+  BLNodeVector _nodes;
+
+  // All edges in the DAG.
+  BLEdgeVector _edges;
+
+  // All backedges in the DAG.
+  BLEdgeVector _backEdges;
+
+  // Allows subclasses to determine which type of Node is created.
+  // Override this method to produce subclasses of BallLarusNode if
+  // necessary. The destructor of BallLarusDag will call free on each pointer
+  // created.
+  virtual BallLarusNode* createNode(BasicBlock* BB);
+
+  // Allows subclasses to determine which type of Edge is created.
+  // Override this method to produce subclasses of BallLarusEdge if
+  // necessary.  Parameters source and target will have been created by
+  // createNode and can be cast to the subclass of BallLarusNode*
+  // returned by createNode. The destructor of BallLarusDag will call free
+  // on each pointer created.
+  virtual BallLarusEdge* createEdge(BallLarusNode* source, BallLarusNode*
+                                    target, unsigned duplicateNumber);
+
+  // Proxy to node's constructor.  Updates the DAG state.
+  BallLarusNode* addNode(BasicBlock* BB);
+
+  // Proxy to edge's constructor.  Updates the DAG state.
+  BallLarusEdge* addEdge(BallLarusNode* source, BallLarusNode* target,
+                         unsigned duplicateNumber);
+
+private:
+  // The root (i.e. entry) node for this DAG.
+  BallLarusNode* _root;
+
+  // The exit node for this DAG.
+  BallLarusNode* _exit;
+
+  // The function represented by this DAG.
+  Function& _function;
+
+  // Processes one node and its imediate edges for building the DAG.
+  void buildNode(BLBlockNodeMap& inDag, std::stack<BallLarusNode*>& dfsStack);
+
+  // Process an edge in the CFG for DAG building.
+  void buildEdge(BLBlockNodeMap& inDag, std::stack<BallLarusNode*>& dfsStack,
+                 BallLarusNode* currentNode, BasicBlock* succBB,
+                 unsigned duplicateNumber);
+
+  // The weight on each edge is the increment required along any path that
+  // contains that edge.
+  void calculatePathNumbersFrom(BallLarusNode* node);
+
+  // Adds a backedge with its phony edges.  Updates the DAG state.
+  void addBackedge(BallLarusNode* source, BallLarusNode* target,
+                   unsigned duplicateCount);
+};
+} // end namespace llvm
+
+#endif

include/llvm/Analysis/PathProfileInfo.h

@@ -0,0 +1,113 @@
+//===- PathProfileInfo.h --------------------------------------*- C++ -*---===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file outlines the interface used by optimizers to load path profiles.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_PATHPROFILEINFO_H
+#define LLVM_PATHPROFILEINFO_H
+
+#include "llvm/BasicBlock.h"
+#include "llvm/Analysis/PathNumbering.h"
+#include <stack>
+
+namespace llvm {
+
+class ProfilePath;
+class ProfilePathEdge;
+class PathProfileInfo;
+
+typedef std::vector<ProfilePathEdge> ProfilePathEdgeVector;
+typedef std::vector<ProfilePathEdge>::iterator ProfilePathEdgeIterator;
+
+typedef std::vector<BasicBlock*> ProfilePathBlockVector;
+typedef std::vector<BasicBlock*>::iterator ProfilePathBlockIterator;
+
+typedef std::map<unsigned int,ProfilePath*> ProfilePathMap;
+typedef std::map<unsigned int,ProfilePath*>::iterator ProfilePathIterator;
+
+typedef std::map<Function*,unsigned int> FunctionPathCountMap;
+typedef std::map<Function*,ProfilePathMap> FunctionPathMap;
+typedef std::map<Function*,ProfilePathMap>::iterator FunctionPathIterator;
+
+class ProfilePathEdge {
+public:
+  ProfilePathEdge(BasicBlock* source, BasicBlock* target,
+                  unsigned duplicateNumber);
+
+  inline unsigned getDuplicateNumber() { return _duplicateNumber; }
+  inline BasicBlock* getSource() { return _source; }
+  inline BasicBlock* getTarget() { return _target; }
+
+protected:
+  BasicBlock* _source;
+  BasicBlock* _target;
+  unsigned _duplicateNumber;
+};
+
+class ProfilePath {
+public:
+  ProfilePath(unsigned int number, unsigned int count,
+              double countStdDev, PathProfileInfo* ppi);
+
+  double getFrequency() const;
+
+  inline unsigned int getNumber() const { return _number; }
+  inline unsigned int getCount() const { return _count; }
+  inline double getCountStdDev() const { return _countStdDev; }
+
+  ProfilePathEdgeVector* getPathEdges() const;
+  ProfilePathBlockVector* getPathBlocks() const;
+
+  BasicBlock* getFirstBlockInPath() const;
+
+private:
+  unsigned int _number;
+  unsigned int _count;
+  double _countStdDev;
+
+  // double pointer back to the profiling info
+  PathProfileInfo* _ppi;
+};
+
+// TODO: overload [] operator for getting path
+// Add: getFunctionCallCount()
+class PathProfileInfo {
+  public:
+  PathProfileInfo();
+  ~PathProfileInfo();
+
+  void setCurrentFunction(Function* F);
+  Function* getCurrentFunction() const;
+  BasicBlock* getCurrentFunctionEntry();
+
+  ProfilePath* getPath(unsigned int number);
+  unsigned int getPotentialPathCount();
+
+  ProfilePathIterator pathBegin();
+  ProfilePathIterator pathEnd();
+  unsigned int pathsRun();
+
+  static char ID; // Pass identification
+  std::string argList;
+
+protected:
+  FunctionPathMap _functionPaths;
+  FunctionPathCountMap _functionPathCounts;
+
+private:
+  BallLarusDag* _currentDag;
+  Function* _currentFunction;
+
+  friend class ProfilePath;
+};
+} // end namespace llvm
+
+#endif

include/llvm/Analysis/ProfileInfoTypes.h

@@ -1,4 +1,4 @@
-/*===-- ProfileInfoTypes.h - Profiling info shared constants ------*- C -*-===*\
+/*===-- ProfileInfoTypes.h - Profiling info shared constants --------------===*\
 |*
 |*                     The LLVM Compiler Infrastructure
 |*
@@ -16,6 +16,17 @@
 #ifndef LLVM_ANALYSIS_PROFILEINFOTYPES_H
 #define LLVM_ANALYSIS_PROFILEINFOTYPES_H
 
+// Included by libprofile.
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+/* IDs to distinguish between those path counters stored in hashses vs arrays */
+enum ProfilingStorageType {
+  ProfilingArray = 1,
+  ProfilingHash = 2
+};
+
 enum ProfilingType {
   ArgumentInfo  = 1,   /* The command line argument block */
   FunctionInfo  = 2,   /* Function profiling information  */
@@ -26,4 +37,24 @@ enum ProfilingType {
   OptEdgeInfo   = 7    /* Edge profiling information, optimal version */
 };
 
+/*
+ * The header for tables that map path numbers to path counters.
+ */
+typedef struct {
+  unsigned fnNumber; /* function number for these counters */
+  unsigned numEntries;   /* number of entries stored */
+} PathProfileHeader;
+
+/*
+ * Describes an entry in a tagged table for path counters.
+ */
+typedef struct {
+  unsigned pathNumber;
+  unsigned pathCounter;
+} PathProfileTableEntry;
+
+#if defined(__cplusplus)
+}
+#endif
+
 #endif /* LLVM_ANALYSIS_PROFILEINFOTYPES_H */

include/llvm/InitializePasses.h

@@ -19,19 +19,19 @@ namespace llvm {
 
 class PassRegistry;
 
-/// initializeCore - Initialize all passes linked into the 
+/// initializeCore - Initialize all passes linked into the
 /// TransformUtils library.
 void initializeCore(PassRegistry&);
 
-/// initializeTransformUtils - Initialize all passes linked into the 
+/// initializeTransformUtils - Initialize all passes linked into the
 /// TransformUtils library.
 void initializeTransformUtils(PassRegistry&);
 
-/// initializeScalarOpts - Initialize all passes linked into the 
+/// initializeScalarOpts - Initialize all passes linked into the
 /// ScalarOpts library.
 void initializeScalarOpts(PassRegistry&);
 
-/// initializeInstCombine - Initialize all passes linked into the 
+/// initializeInstCombine - Initialize all passes linked into the
 /// ScalarOpts library.
 void initializeInstCombine(PassRegistry&);
 
@@ -93,6 +93,7 @@ void initializeDominanceFrontierPass(PassRegistry&);
 void initializeDominatorTreePass(PassRegistry&);
 void initializeEdgeBundlesPass(PassRegistry&);
 void initializeEdgeProfilerPass(PassRegistry&);
+void initializePathProfilerPass(PassRegistry&);
 void initializeEarlyCSEPass(PassRegistry&);
 void initializeExpandISelPseudosPass(PassRegistry&);
 void initializeFindUsedTypesPass(PassRegistry&);
@@ -125,6 +126,7 @@ void initializeLiveStacksPass(PassRegistry&);
 void initializeLiveValuesPass(PassRegistry&);
 void initializeLiveVariablesPass(PassRegistry&);
 void initializeLoaderPassPass(PassRegistry&);
+void initializePathProfileLoaderPassPass(PassRegistry&);
 void initializeLoopDeletionPass(PassRegistry&);
 void initializeLoopDependenceAnalysisPass(PassRegistry&);
 void initializeLoopExtractorPass(PassRegistry&);
@@ -157,6 +159,7 @@ void initializeMergeFunctionsPass(PassRegistry&);
 void initializeModuleDebugInfoPrinterPass(PassRegistry&);
 void initializeNoAAPass(PassRegistry&);
 void initializeNoProfileInfoPass(PassRegistry&);
+void initializeNoPathProfileInfoPass(PassRegistry&);
 void initializeOptimalEdgeProfilerPass(PassRegistry&);
 void initializeOptimizePHIsPass(PassRegistry&);
 void initializePEIPass(PassRegistry&);
@@ -177,6 +180,8 @@ void initializePrintModulePassPass(PassRegistry&);
 void initializeProcessImplicitDefsPass(PassRegistry&);
 void initializeProfileEstimatorPassPass(PassRegistry&);
 void initializeProfileInfoAnalysisGroup(PassRegistry&);
+void initializePathProfileInfoAnalysisGroup(PassRegistry&);
+void initializePathProfileVerifierPass(PassRegistry&);
 void initializeProfileVerifierPassPass(PassRegistry&);
 void initializePromotePassPass(PassRegistry&);
 void initializePruneEHPass(PassRegistry&);

include/llvm/LinkAllPasses.h

@@ -7,7 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// This header file pulls in all transformation and analysis passes for tools 
+// This header file pulls in all transformation and analysis passes for tools
 // like opt and bugpoint that need this functionality.
 //
 //===----------------------------------------------------------------------===//
@@ -70,6 +70,7 @@ namespace {
       (void) llvm::createDomViewerPass();
       (void) llvm::createEdgeProfilerPass();
       (void) llvm::createOptimalEdgeProfilerPass();
+      (void) llvm::createPathProfilerPass();
       (void) llvm::createFunctionInliningPass();
       (void) llvm::createAlwaysInlinerPass();
       (void) llvm::createGlobalDCEPass();
@@ -99,7 +100,9 @@ namespace {
       (void) llvm::createNoProfileInfoPass();
       (void) llvm::createProfileEstimatorPass();
       (void) llvm::createProfileVerifierPass();
+      (void) llvm::createPathProfileVerifierPass();
       (void) llvm::createProfileLoaderPass();
+      (void) llvm::createPathProfileLoaderPass();
       (void) llvm::createPromoteMemoryToRegisterPass();
       (void) llvm::createDemoteRegisterToMemoryPass();
       (void) llvm::createPruneEHPass();

include/llvm/Transforms/Instrumentation.h

@@ -25,6 +25,9 @@ ModulePass *createEdgeProfilerPass();
 // Insert optimal edge profiling instrumentation
 ModulePass *createOptimalEdgeProfilerPass();
 
+// Insert path profiling instrumentation
+ModulePass *createPathProfilerPass();
+
 } // End llvm namespace
 
 #endif

lib/Analysis/Analysis.cpp

@@ -53,9 +53,13 @@ void llvm::initializeAnalysis(PassRegistry &Registry) {
   initializePostDominanceFrontierPass(Registry);
   initializeProfileEstimatorPassPass(Registry);
   initializeNoProfileInfoPass(Registry);
+  initializeNoPathProfileInfoPass(Registry);
   initializeProfileInfoAnalysisGroup(Registry);
+  initializePathProfileInfoAnalysisGroup(Registry);
   initializeLoaderPassPass(Registry);
+  initializePathProfileLoaderPassPass(Registry);
   initializeProfileVerifierPassPass(Registry);
+  initializePathProfileVerifierPass(Registry);
   initializeRegionInfoPass(Registry);
   initializeRegionViewerPass(Registry);
   initializeRegionPrinterPass(Registry);
@@ -73,14 +77,14 @@ void LLVMInitializeAnalysis(LLVMPassRegistryRef R) {
 LLVMBool LLVMVerifyModule(LLVMModuleRef M, LLVMVerifierFailureAction Action,
                           char **OutMessages) {
   std::string Messages;
-  
+
   LLVMBool Result = verifyModule(*unwrap(M),
                             static_cast<VerifierFailureAction>(Action),
                             OutMessages? &Messages : 0);
-  
+
   if (OutMessages)
     *OutMessages = strdup(Messages.c_str());
-  
+
   return Result;
 }
 

lib/Analysis/CMakeLists.txt

@@ -33,6 +33,9 @@ add_llvm_library(LLVMAnalysis
   MemoryBuiltins.cpp
   MemoryDependenceAnalysis.cpp
   ModuleDebugInfoPrinter.cpp
+  PathNumbering.cpp
+  PathProfileInfo.cpp
+  PathProfileVerifier.cpp
   NoAliasAnalysis.cpp
   PHITransAddr.cpp
   PostDominators.cpp

lib/Analysis/PathNumbering.cpp

@@ -0,0 +1,525 @@
+//===- PathNumbering.cpp --------------------------------------*- C++ -*---===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Ball-Larus path numbers uniquely identify paths through a directed acyclic
+// graph (DAG) [Ball96].  For a CFG backedges are removed and replaced by phony
+// edges to obtain a DAG, and thus the unique path numbers [Ball96].
+//
+// The purpose of this analysis is to enumerate the edges in a CFG in order
+// to obtain paths from path numbers in a convenient manner.  As described in
+// [Ball96] edges can be enumerated such that given a path number by following
+// the CFG and updating the path number, the path is obtained.
+//
+// [Ball96]
+//  T. Ball and J. R. Larus. "Efficient Path Profiling."
+//  International Symposium on Microarchitecture, pages 46-57, 1996.
+//  http://portal.acm.org/citation.cfm?id=243857
+//
+//===----------------------------------------------------------------------===//
+#define DEBUG_TYPE "ball-larus-numbering"
+
+#include "llvm/Analysis/PathNumbering.h"
+#include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/InstrTypes.h"
+#include "llvm/Instructions.h"
+#include "llvm/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/CFG.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/TypeBuilder.h"
+#include "llvm/Support/raw_ostream.h"
+
+#include <map>
+#include <queue>
+#include <set>
+#include <stack>
+#include <string>
+#include <utility>
+#include <vector>
+#include <sstream>
+
+using namespace llvm;
+
+// Are we enabling early termination
+static cl::opt<bool> ProcessEarlyTermination(
+  "path-profile-early-termination", cl::Hidden,
+  cl::desc("In path profiling, insert extra instrumentation to account for "
+           "unexpected function termination."));
+
+// Returns the basic block for the BallLarusNode
+BasicBlock* BallLarusNode::getBlock() {
+  return(_basicBlock);
+}
+
+// Returns the number of paths to the exit starting at the node.
+unsigned BallLarusNode::getNumberPaths() {
+  return(_numberPaths);
+}
+
+// Sets the number of paths to the exit starting at the node.
+void BallLarusNode::setNumberPaths(unsigned numberPaths) {
+  _numberPaths = numberPaths;
+}
+
+// Gets the NodeColor used in graph algorithms.
+BallLarusNode::NodeColor BallLarusNode::getColor() {
+  return(_color);
+}
+
+// Sets the NodeColor used in graph algorithms.
+void BallLarusNode::setColor(BallLarusNode::NodeColor color) {
+  _color = color;
+}
+
+// Returns an iterator over predecessor edges. Includes phony and
+// backedges.
+BLEdgeIterator BallLarusNode::predBegin() {
+  return(_predEdges.begin());
+}
+
+// Returns the end sentinel for the predecessor iterator.
+BLEdgeIterator BallLarusNode::predEnd() {
+  return(_predEdges.end());
+}
+
+// Returns the number of predecessor edges.  Includes phony and
+// backedges.
+unsigned BallLarusNode::getNumberPredEdges() {
+  return(_predEdges.size());
+}
+
+// Returns an iterator over successor edges. Includes phony and
+// backedges.
+BLEdgeIterator BallLarusNode::succBegin() {
+  return(_succEdges.begin());
+}
+
+// Returns the end sentinel for the successor iterator.
+BLEdgeIterator BallLarusNode::succEnd() {
+  return(_succEdges.end());
+}
+
+// Returns the number of successor edges.  Includes phony and
+// backedges.
+unsigned BallLarusNode::getNumberSuccEdges() {
+  return(_succEdges.size());
+}
+
+// Add an edge to the predecessor list.
+void BallLarusNode::addPredEdge(BallLarusEdge* edge) {
+  _predEdges.push_back(edge);
+}
+
+// Remove an edge from the predecessor list.
+void BallLarusNode::removePredEdge(BallLarusEdge* edge) {
+  removeEdge(_predEdges, edge);
+}
+
+// Add an edge to the successor list.
+void BallLarusNode::addSuccEdge(BallLarusEdge* edge) {
+  _succEdges.push_back(edge);
+}
+
+// Remove an edge from the successor list.
+void BallLarusNode::removeSuccEdge(BallLarusEdge* edge) {
+  removeEdge(_succEdges, edge);
+}
+
+// Returns the name of the BasicBlock being represented.  If BasicBlock
+// is null then returns "<null>".  If BasicBlock has no name, then
+// "<unnamed>" is returned.  Intended for use with debug output.
+std::string BallLarusNode::getName() {
+  std::stringstream name;
+
+  if(getBlock() != NULL) {
+    if(getBlock()->hasName()) {
+      std::string tempName(getBlock()->getName());
+      name << tempName.c_str() << " (" << _uid << ")";
+    } else
+      name << "<unnamed> (" << _uid << ")";
+  } else
+    name << "<null> (" << _uid << ")";
+
+  return name.str();
+}
+
+// Removes an edge from an edgeVector.  Used by removePredEdge and
+// removeSuccEdge.
+void BallLarusNode::removeEdge(BLEdgeVector& v, BallLarusEdge* e) {
+  // TODO: Avoid linear scan by using a set instead
+  for(BLEdgeIterator i = v.begin(),
+        end = v.end();
+      i != end;
+      ++i) {
+    if((*i) == e) {
+      v.erase(i);
+      break;
+    }
+  }
+}
+
+// Returns the source node of this edge.
+BallLarusNode* BallLarusEdge::getSource() const {
+  return(_source);
+}
+
+// Returns the target node of this edge.
+BallLarusNode* BallLarusEdge::getTarget() const {
+  return(_target);
+}
+
+// Sets the type of the edge.
+BallLarusEdge::EdgeType BallLarusEdge::getType() const {
+  return _edgeType;
+}
+
+// Gets the type of the edge.
+void BallLarusEdge::setType(EdgeType type) {
+  _edgeType = type;
+}
+
+// Returns the weight of this edge.  Used to decode path numbers to sequences
+// of basic blocks.
+unsigned BallLarusEdge::getWeight() {
+  return(_weight);
+}
+
+// Sets the weight of the edge.  Used during path numbering.
+void BallLarusEdge::setWeight(unsigned weight) {
+  _weight = weight;
+}
+
+// Gets the phony edge originating at the root.
+BallLarusEdge* BallLarusEdge::getPhonyRoot() {
+  return _phonyRoot;
+}
+
+// Sets the phony edge originating at the root.
+void BallLarusEdge::setPhonyRoot(BallLarusEdge* phonyRoot) {
+  _phonyRoot = phonyRoot;
+}
+
+// Gets the phony edge terminating at the exit.
+BallLarusEdge* BallLarusEdge::getPhonyExit() {
+  return _phonyExit;
+}
+
+// Sets the phony edge terminating at the exit.
+void BallLarusEdge::setPhonyExit(BallLarusEdge* phonyExit) {
+  _phonyExit = phonyExit;
+}
+
+// Gets the associated real edge if this is a phony edge.
+BallLarusEdge* BallLarusEdge::getRealEdge() {
+  return _realEdge;
+}
+
+// Sets the associated real edge if this is a phony edge.
+void BallLarusEdge::setRealEdge(BallLarusEdge* realEdge) {
+  _realEdge = realEdge;
+}
+
+// Returns the duplicate number of the edge.
+unsigned BallLarusEdge::getDuplicateNumber() {
+  return(_duplicateNumber);
+}
+
+// Initialization that requires virtual functions which are not fully
+// functional in the constructor.
+void BallLarusDag::init() {
+  BLBlockNodeMap inDag;
+  std::stack<BallLarusNode*> dfsStack;
+
+  _root = addNode(&(_function.getEntryBlock()));
+  _exit = addNode(NULL);
+
+  // start search from root
+  dfsStack.push(getRoot());
+
+  // dfs to add each bb into the dag
+  while(dfsStack.size())
+    buildNode(inDag, dfsStack);
+
+  // put in the final edge
+  addEdge(getExit(),getRoot(),0);
+}
+
+// Frees all memory associated with the DAG.
+BallLarusDag::~BallLarusDag() {
+  for(BLEdgeIterator edge = _edges.begin(), end = _edges.end(); edge != end;
+      ++edge)
+    delete (*edge);
+
+  for(BLNodeIterator node = _nodes.begin(), end = _nodes.end(); node != end;
+      ++node)
+    delete (*node);
+}
+
+// Calculate the path numbers by assigning edge increments as prescribed
+// in Ball-Larus path profiling.
+void BallLarusDag::calculatePathNumbers() {
+  BallLarusNode* node;
+  std::queue<BallLarusNode*> bfsQueue;
+  bfsQueue.push(getExit());
+
+  while(bfsQueue.size() > 0) {
+    node = bfsQueue.front();
+
+    DEBUG(dbgs() << "calculatePathNumbers on " << node->getName() << "\n");
+
+    bfsQueue.pop();
+    unsigned prevPathNumber = node->getNumberPaths();
+    calculatePathNumbersFrom(node);
+
+    // Check for DAG splitting
+    if( node->getNumberPaths() > 100000000 && node != getRoot() ) {
+      // Add new phony edge from the split-node to the DAG's exit
+      BallLarusEdge* exitEdge = addEdge(node, getExit(), 0);
+      exitEdge->setType(BallLarusEdge::SPLITEDGE_PHONY);
+
+      // Counters to handle the possibilty of a multi-graph
+      BasicBlock* oldTarget = 0;
+      unsigned duplicateNumber = 0;
+
+      // Iterate through each successor edge, adding phony edges
+      for( BLEdgeIterator succ = node->succBegin(), end = node->succEnd();
+           succ != end; oldTarget = (*succ)->getTarget()->getBlock(), succ++ ) {
+
+        if( (*succ)->getType() == BallLarusEdge::NORMAL ) {
+          // is this edge a duplicate?
+          if( oldTarget != (*succ)->getTarget()->getBlock() )
+            duplicateNumber = 0;
+
+          // create the new phony edge: root -> succ
+          BallLarusEdge* rootEdge =
+            addEdge(getRoot(), (*succ)->getTarget(), duplicateNumber++);
+          rootEdge->setType(BallLarusEdge::SPLITEDGE_PHONY);
+          rootEdge->setRealEdge(*succ);
+
+          // split on this edge and reference it's exit/root phony edges
+          (*succ)->setType(BallLarusEdge::SPLITEDGE);
+          (*succ)->setPhonyRoot(rootEdge);
+          (*succ)->setPhonyExit(exitEdge);
+          (*succ)->setWeight(0);
+        }
+      }
+
+      calculatePathNumbersFrom(node);
+    }
+
+    DEBUG(dbgs() << "prev, new number paths " << prevPathNumber << ", "
+          << node->getNumberPaths() << ".\n");
+
+    if(prevPathNumber == 0 && node->getNumberPaths() != 0) {
+      DEBUG(dbgs() << "node ready : " << node->getName() << "\n");
+      for(BLEdgeIterator pred = node->predBegin(), end = node->predEnd();
+          pred != end; pred++) {
+        if( (*pred)->getType() == BallLarusEdge::BACKEDGE ||
+            (*pred)->getType() == BallLarusEdge::SPLITEDGE )
+          continue;
+
+        BallLarusNode* nextNode = (*pred)->getSource();
+        // not yet visited?
+        if(nextNode->getNumberPaths() == 0)
+          bfsQueue.push(nextNode);
+      }
+    }
+  }
+
+  DEBUG(dbgs() << "\tNumber of paths: " << getRoot()->getNumberPaths() << "\n");
+}
+
+// Returns the number of paths for the Dag.
+unsigned BallLarusDag::getNumberOfPaths() {
+  return(getRoot()->getNumberPaths());
+}
+
+// Returns the root (i.e. entry) node for the DAG.
+BallLarusNode* BallLarusDag::getRoot() {
+  return _root;
+}
+
+// Returns the exit node for the DAG.
+BallLarusNode* BallLarusDag::getExit() {
+  return _exit;
+}
+
+// Returns the function for the DAG.
+Function& BallLarusDag::getFunction() {
+  return(_function);
+}
+
+// Clears the node colors.
+void BallLarusDag::clearColors(BallLarusNode::NodeColor color) {
+  for (BLNodeIterator nodeIt = _nodes.begin(); nodeIt != _nodes.end(); nodeIt++)
+    (*nodeIt)->setColor(color);
+}
+
+// Processes one node and its imediate edges for building the DAG.
+void BallLarusDag::buildNode(BLBlockNodeMap& inDag, BLNodeStack& dfsStack) {
+  BallLarusNode* currentNode = dfsStack.top();
+  BasicBlock* currentBlock = currentNode->getBlock();
+
+  if(currentNode->getColor() != BallLarusNode::WHITE) {
+    // we have already visited this node
+    dfsStack.pop();
+    currentNode->setColor(BallLarusNode::BLACK);
+  } else {
+    // are there any external procedure calls?
+    if( ProcessEarlyTermination ) {
+      for( BasicBlock::iterator bbCurrent = currentNode->getBlock()->begin(),
+             bbEnd = currentNode->getBlock()->end(); bbCurrent != bbEnd;
+           bbCurrent++ ) {
+        Instruction& instr = *bbCurrent;
+        if( instr.getOpcode() == Instruction::Call ) {
+          BallLarusEdge* callEdge = addEdge(currentNode, getExit(), 0);
+          callEdge->setType(BallLarusEdge::CALLEDGE_PHONY);
+          break;
+        }
+      }
+    }
+
+    TerminatorInst* terminator = currentNode->getBlock()->getTerminator();
+    if(isa<ReturnInst>(terminator) || isa<UnreachableInst>(terminator)
+       || isa<UnwindInst>(terminator))
+      addEdge(currentNode, getExit(),0);
+
+    currentNode->setColor(BallLarusNode::GRAY);
+    inDag[currentBlock] = currentNode;
+
+    BasicBlock* oldSuccessor = 0;
+    unsigned duplicateNumber = 0;
+
+    // iterate through this node's successors
+    for(succ_iterator successor = succ_begin(currentBlock),
+          succEnd = succ_end(currentBlock); successor != succEnd;
+        oldSuccessor = *successor, ++successor ) {
+      BasicBlock* succBB = *successor;
+
+      // is this edge a duplicate?
+      if (oldSuccessor == succBB)
+        duplicateNumber++;
+      else
+        duplicateNumber = 0;
+
+      buildEdge(inDag, dfsStack, currentNode, succBB, duplicateNumber);
+    }
+  }
+}
+
+// Process an edge in the CFG for DAG building.
+void BallLarusDag::buildEdge(BLBlockNodeMap& inDag, std::stack<BallLarusNode*>&
+                             dfsStack, BallLarusNode* currentNode,
+                             BasicBlock* succBB, unsigned duplicateCount) {
+  BallLarusNode* succNode = inDag[succBB];
+
+  if(succNode && succNode->getColor() == BallLarusNode::BLACK) {
+    // visited node and forward edge
+    addEdge(currentNode, succNode, duplicateCount);
+  } else if(succNode && succNode->getColor() == BallLarusNode::GRAY) {
+    // visited node and back edge
+    DEBUG(dbgs() << "Backedge detected.\n");
+    addBackedge(currentNode, succNode, duplicateCount);
+  } else {
+    BallLarusNode* childNode;
+    // not visited node and forward edge
+    if(succNode) // an unvisited node that is child of a gray node
+      childNode = succNode;
+    else { // an unvisited node that is a child of a an unvisted node
+      childNode = addNode(succBB);
+      inDag[succBB] = childNode;
+    }
+    addEdge(currentNode, childNode, duplicateCount);
+    dfsStack.push(childNode);
+  }
+}
+
+// The weight on each edge is the increment required along any path that
+// contains that edge.
+void BallLarusDag::calculatePathNumbersFrom(BallLarusNode* node) {
+  if(node == getExit())
+    // The Exit node must be base case
+    node->setNumberPaths(1);
+  else {
+    unsigned sumPaths = 0;
+    BallLarusNode* succNode;
+
+    for(BLEdgeIterator succ = node->succBegin(), end = node->succEnd();
+        succ != end; succ++) {
+      if( (*succ)->getType() == BallLarusEdge::BACKEDGE ||
+          (*succ)->getType() == BallLarusEdge::SPLITEDGE )
+        continue;
+
+      (*succ)->setWeight(sumPaths);
+      succNode = (*succ)->getTarget();
+
+      if( !succNode->getNumberPaths() )
+        return;
+      sumPaths += succNode->getNumberPaths();
+    }
+
+    node->setNumberPaths(sumPaths);
+  }
+}
+
+// Allows subclasses to determine which type of Node is created.
+// Override this method to produce subclasses of BallLarusNode if
+// necessary. The destructor of BallLarusDag will call free on each
+// pointer created.
+BallLarusNode* BallLarusDag::createNode(BasicBlock* BB) {
+  return( new BallLarusNode(BB) );
+}
+
+// Allows subclasses to determine which type of Edge is created.
+// Override this method to produce subclasses of BallLarusEdge if
+// necessary. The destructor of BallLarusDag will call free on each
+// pointer created.
+BallLarusEdge* BallLarusDag::createEdge(BallLarusNode* source,
+                                        BallLarusNode* target,
+                                        unsigned duplicateCount) {
+  return( new BallLarusEdge(source, target, duplicateCount) );
+}
+
+// Proxy to node's constructor.  Updates the DAG state.
+BallLarusNode* BallLarusDag::addNode(BasicBlock* BB) {
+  BallLarusNode* newNode = createNode(BB);
+  _nodes.push_back(newNode);
+  return( newNode );
+}
+
+// Proxy to edge's constructor. Updates the DAG state.
+BallLarusEdge* BallLarusDag::addEdge(BallLarusNode* source,
+                                     BallLarusNode* target,
+                                     unsigned duplicateCount) {
+  BallLarusEdge* newEdge = createEdge(source, target, duplicateCount);
+  _edges.push_back(newEdge);
+  source->addSuccEdge(newEdge);
+  target->addPredEdge(newEdge);
+  return(newEdge);
+}
+
+// Adds a backedge with its phony edges. Updates the DAG state.
+void BallLarusDag::addBackedge(BallLarusNode* source, BallLarusNode* target,
+                               unsigned duplicateCount) {
+  BallLarusEdge* childEdge = addEdge(source, target, duplicateCount);
+  childEdge->setType(BallLarusEdge::BACKEDGE);
+
+  childEdge->setPhonyRoot(addEdge(getRoot(), target,0));
+  childEdge->setPhonyExit(addEdge(source, getExit(),0));
+
+  childEdge->getPhonyRoot()->setRealEdge(childEdge);
+  childEdge->getPhonyRoot()->setType(BallLarusEdge::BACKEDGE_PHONY);
+
+  childEdge->getPhonyExit()->setRealEdge(childEdge);
+  childEdge->getPhonyExit()->setType(BallLarusEdge::BACKEDGE_PHONY);
+  _backEdges.push_back(childEdge);
+}

lib/Analysis/PathProfileInfo.cpp

@@ -0,0 +1,434 @@
+//===- PathProfileInfo.cpp ------------------------------------*- C++ -*---===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the interface used by optimizers to load path profiles,
+// and provides a loader pass which reads a path profile file.
+//
+//===----------------------------------------------------------------------===//
+#define DEBUG_TYPE "path-profile-info"
+
+#include "llvm/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/Analysis/Passes.h"
+#include "llvm/Analysis/ProfileInfoTypes.h"
+#include "llvm/Analysis/PathProfileInfo.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+
+#include <cstdio>
+
+using namespace llvm;
+
+// command line option for loading path profiles
+static cl::opt<std::string>
+PathProfileInfoFilename("path-profile-loader-file", cl::init("llvmprof.out"),
+  cl::value_desc("filename"),
+  cl::desc("Path profile file loaded by -path-profile-loader"), cl::Hidden);
+
+namespace {
+  class PathProfileLoaderPass : public ModulePass, public PathProfileInfo {
+  public:
+    PathProfileLoaderPass() : ModulePass(ID) { }
+    ~PathProfileLoaderPass();
+
+    // this pass doesn't change anything (only loads information)
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+      AU.setPreservesAll();
+    }
+
+    // the full name of the loader pass
+    virtual const char* getPassName() const {
+      return "Path Profiling Information Loader";
+    }
+
+    // required since this pass implements multiple inheritance
+                virtual void *getAdjustedAnalysisPointer(AnalysisID PI) {
+      if (PI == &PathProfileInfo::ID)
+        return (PathProfileInfo*)this;
+      return this;
+    }
+
+    // entry point to run the pass
+    bool runOnModule(Module &M);
+
+    // pass identification
+    static char ID;
+
+  private:
+    // make a reference table to refer to function by number
+    void buildFunctionRefs(Module &M);
+
+    // process argument info of a program from the input file
+    void handleArgumentInfo();
+
+    // process path number information from the input file
+    void handlePathInfo();
+
+    // array of references to the functions in the module
+    std::vector<Function*> _functions;
+
+    // path profile file handle
+    FILE* _file;
+
+    // path profile file name
+    std::string _filename;
+  };
+}
+
+// register PathLoader
+char PathProfileLoaderPass::ID = 0;
+
+INITIALIZE_ANALYSIS_GROUP(PathProfileInfo, "Path Profile Information",
+                          NoPathProfileInfo)
+INITIALIZE_AG_PASS(PathProfileLoaderPass, PathProfileInfo,
+                   "path-profile-loader",
+                   "Load path profile information from file",
+                   false, true, false)
+
+char &llvm::PathProfileLoaderPassID = PathProfileLoaderPass::ID;
+
+// link PathLoader as a pass, and make it available as an optimisation
+ModulePass *llvm::createPathProfileLoaderPass() {
+  return new PathProfileLoaderPass;
+}
+
+// ----------------------------------------------------------------------------
+// PathEdge implementation
+//
+ProfilePathEdge::ProfilePathEdge (BasicBlock* source, BasicBlock* target,
+                                  unsigned duplicateNumber)
+  : _source(source), _target(target), _duplicateNumber(duplicateNumber) {}
+
+// ----------------------------------------------------------------------------
+// Path implementation
+//
+
+ProfilePath::ProfilePath (unsigned int number, unsigned int count,
+                          double countStdDev,   PathProfileInfo* ppi)
+  : _number(number) , _count(count), _countStdDev(countStdDev), _ppi(ppi) {}
+
+double ProfilePath::getFrequency() const {
+  return 100 * double(_count) /
+    double(_ppi->_functionPathCounts[_ppi->_currentFunction]);
+}
+
+static BallLarusEdge* getNextEdge (BallLarusNode* node,
+                                   unsigned int pathNumber) {
+  BallLarusEdge* best = 0;
+
+  for( BLEdgeIterator next = node->succBegin(),
+         end = node->succEnd(); next != end; next++ ) {
+    if( (*next)->getType() != BallLarusEdge::BACKEDGE && // no backedges
+        (*next)->getType() != BallLarusEdge::SPLITEDGE && // no split edges
+        (*next)->getWeight() <= pathNumber && // weight must be <= pathNumber
+        (!best || (best->getWeight() < (*next)->getWeight())) ) // best one?
+      best = *next;
+  }
+
+  return best;
+}
+
+ProfilePathEdgeVector* ProfilePath::getPathEdges() const {
+  BallLarusNode* currentNode = _ppi->_currentDag->getRoot ();
+  unsigned int increment = _number;
+  ProfilePathEdgeVector* pev = new ProfilePathEdgeVector;
+
+  while (currentNode != _ppi->_currentDag->getExit()) {
+    BallLarusEdge* next = getNextEdge(currentNode, increment);
+
+    increment -= next->getWeight();
+
+    if( next->getType() != BallLarusEdge::BACKEDGE_PHONY &&
+        next->getType() != BallLarusEdge::SPLITEDGE_PHONY &&
+        next->getTarget() != _ppi->_currentDag->getExit() )
+      pev->push_back(ProfilePathEdge(
+                       next->getSource()->getBlock(),
+                       next->getTarget()->getBlock(),
+                       next->getDuplicateNumber()));
+
+    if( next->getType() == BallLarusEdge::BACKEDGE_PHONY &&
+        next->getTarget() == _ppi->_currentDag->getExit() )
+      pev->push_back(ProfilePathEdge(
+                       next->getRealEdge()->getSource()->getBlock(),
+                       next->getRealEdge()->getTarget()->getBlock(),
+                       next->getDuplicateNumber()));
+
+    if( next->getType() == BallLarusEdge::SPLITEDGE_PHONY &&
+        next->getSource() == _ppi->_currentDag->getRoot() )
+      pev->push_back(ProfilePathEdge(
+                       next->getRealEdge()->getSource()->getBlock(),
+                       next->getRealEdge()->getTarget()->getBlock(),
+                       next->getDuplicateNumber()));
+
+    // set the new node
+    currentNode = next->getTarget();
+  }
+
+  return pev;
+}
+
+ProfilePathBlockVector* ProfilePath::getPathBlocks() const {
+  BallLarusNode* currentNode = _ppi->_currentDag->getRoot ();
+  unsigned int increment = _number;
+  ProfilePathBlockVector* pbv = new ProfilePathBlockVector;
+
+  while (currentNode != _ppi->_currentDag->getExit()) {
+    BallLarusEdge* next = getNextEdge(currentNode, increment);
+    increment -= next->getWeight();
+
+    // add block to the block list if it is a real edge
+    if( next->getType() == BallLarusEdge::NORMAL)
+      pbv->push_back (currentNode->getBlock());
+    // make the back edge the last edge since we are at the end
+    else if( next->getTarget() == _ppi->_currentDag->getExit() ) {
+      pbv->push_back (currentNode->getBlock());
+      pbv->push_back (next->getRealEdge()->getTarget()->getBlock());
+    }
+
+    // set the new node
+    currentNode = next->getTarget();
+  }
+
+  return pbv;
+}
+
+BasicBlock* ProfilePath::getFirstBlockInPath() const {
+  BallLarusNode* root = _ppi->_currentDag->getRoot();
+  BallLarusEdge* edge = getNextEdge(root, _number);
+
+  if( edge && (edge->getType() == BallLarusEdge::BACKEDGE_PHONY ||
+               edge->getType() == BallLarusEdge::SPLITEDGE_PHONY) )
+    return edge->getTarget()->getBlock();
+
+  return root->getBlock();
+}
+
+// ----------------------------------------------------------------------------
+// PathProfileInfo implementation
+//
+
+// Pass identification
+char llvm::PathProfileInfo::ID = 0;
+
+PathProfileInfo::PathProfileInfo () : _currentDag(0) , _currentFunction(0) {
+}
+
+PathProfileInfo::~PathProfileInfo() {
+  if (_currentDag)
+    delete _currentDag;
+}
+
+// set the function for which paths are currently begin processed
+void PathProfileInfo::setCurrentFunction(Function* F) {
+  // Make sure it exists
+  if (!F) return;
+
+  if (_currentDag)
+    delete _currentDag;
+
+  _currentFunction = F;
+  _currentDag = new BallLarusDag(*F);
+  _currentDag->init();
+  _currentDag->calculatePathNumbers();
+}
+
+// get the function for which paths are currently being processed
+Function* PathProfileInfo::getCurrentFunction() const {
+  return _currentFunction;
+}
+
+// get the entry block of the function
+BasicBlock* PathProfileInfo::getCurrentFunctionEntry() {
+  return _currentDag->getRoot()->getBlock();
+}
+
+// return the path based on its number
+ProfilePath* PathProfileInfo::getPath(unsigned int number) {
+  return _functionPaths[_currentFunction][number];
+}
+
+// return the number of paths which a function may potentially execute
+unsigned int PathProfileInfo::getPotentialPathCount() {
+  return _currentDag ? _currentDag->getNumberOfPaths() : 0;
+}
+
+// return an iterator for the beginning of a functions executed paths
+ProfilePathIterator PathProfileInfo::pathBegin() {
+  return _functionPaths[_currentFunction].begin();
+}
+
+// return an iterator for the end of a functions executed paths
+ProfilePathIterator PathProfileInfo::pathEnd() {
+  return _functionPaths[_currentFunction].end();
+}
+
+// returns the total number of paths run in the function
+unsigned int PathProfileInfo::pathsRun() {
+  return _currentFunction ? _functionPaths[_currentFunction].size() : 0;
+}
+
+// ----------------------------------------------------------------------------
+// PathLoader implementation
+//
+
+// remove all generated paths
+PathProfileLoaderPass::~PathProfileLoaderPass() {
+  for( FunctionPathIterator funcNext = _functionPaths.begin(),
+         funcEnd = _functionPaths.end(); funcNext != funcEnd; funcNext++)
+    for( ProfilePathIterator pathNext = funcNext->second.begin(),
+           pathEnd = funcNext->second.end(); pathNext != pathEnd; pathNext++)
+      delete pathNext->second;
+}
+
+// entry point of the pass; this loads and parses a file
+bool PathProfileLoaderPass::runOnModule(Module &M) {
+  // get the filename and setup the module's function references
+  _filename = PathProfileInfoFilename;
+  buildFunctionRefs (M);
+
+  if (!(_file = fopen(_filename.c_str(), "rb"))) {
+    errs () << "error: input '" << _filename << "' file does not exist.\n";
+    return false;
+  }
+
+  ProfilingType profType;
+
+  while( fread(&profType, sizeof(ProfilingType), 1, _file) ) {
+    switch (profType) {
+    case ArgumentInfo:
+      handleArgumentInfo ();
+      break;
+    case PathInfo:
+      handlePathInfo ();
+      break;
+    default:
+      errs () << "error: bad path profiling file syntax, " << profType << "\n";
+      fclose (_file);
+      return false;
+    }
+  }
+
+  fclose (_file);
+
+  return true;
+}
+
+// create a reference table for functions defined in the path profile file
+void PathProfileLoaderPass::buildFunctionRefs (Module &M) {
+  _functions.push_back(0); // make the 0 index a null pointer
+
+  for (Module::iterator F = M.begin(), E = M.end(); F != E; F++) {
+    if (F->isDeclaration())
+      continue;
+    _functions.push_back(F);
+  }
+}
+
+// handle command like argument infor in the output file
+void PathProfileLoaderPass::handleArgumentInfo() {
+  // get the argument list's length
+  unsigned savedArgsLength;
+  if( fread(&savedArgsLength, sizeof(unsigned), 1, _file) != 1 ) {
+    errs() << "warning: argument info header/data mismatch\n";
+    return;
+  }
+
+  // allocate a buffer, and get the arguments
+  char* args = new char[savedArgsLength+1];
+  if( fread(args, 1, savedArgsLength, _file) != savedArgsLength )
+    errs() << "warning: argument info header/data mismatch\n";
+
+  args[savedArgsLength] = '\0';
+  argList = std::string(args);
+  delete [] args; // cleanup dynamic string
+
+  // byte alignment
+  if (savedArgsLength & 3)
+    fseek(_file, 4-(savedArgsLength&3), SEEK_CUR);
+}
+
+// Handle path profile information in the output file
+void PathProfileLoaderPass::handlePathInfo () {
+  // get the number of functions in this profile
+  unsigned functionCount;
+  if( fread(&functionCount, sizeof(functionCount), 1, _file) != 1 ) {
+    errs() << "warning: path info header/data mismatch\n";
+    return;
+  }
+
+  // gather path information for each function
+  for (unsigned i = 0; i < functionCount; i++) {
+    PathProfileHeader pathHeader;
+    if( fread(&pathHeader, sizeof(pathHeader), 1, _file) != 1 ) {
+      errs() << "warning: bad header for path function info\n";
+      break;
+    }
+
+    Function* f = _functions[pathHeader.fnNumber];
+
+    // dynamically allocate a table to store path numbers
+    PathProfileTableEntry* pathTable =
+      new PathProfileTableEntry[pathHeader.numEntries];
+
+    if( fread(pathTable, sizeof(PathProfileTableEntry),
+              pathHeader.numEntries, _file) != pathHeader.numEntries) {
+      delete [] pathTable;
+      errs() << "warning: path function info header/data mismatch\n";
+      return;
+    }
+
+    // Build a new path for the current function
+    unsigned int totalPaths = 0;
+    for (unsigned int j = 0; j < pathHeader.numEntries; j++) {
+      totalPaths += pathTable[j].pathCounter;
+      _functionPaths[f][pathTable[j].pathNumber]
+        = new ProfilePath(pathTable[j].pathNumber, pathTable[j].pathCounter,
+                          0, this);
+    }
+
+    _functionPathCounts[f] = totalPaths;
+
+    delete [] pathTable;
+  }
+}
+
+//===----------------------------------------------------------------------===//
+//  NoProfile PathProfileInfo implementation
+//
+
+namespace {
+  struct NoPathProfileInfo : public ImmutablePass, public PathProfileInfo {
+    static char ID; // Class identification, replacement for typeinfo
+    NoPathProfileInfo() : ImmutablePass(ID) {
+      initializeNoPathProfileInfoPass(*PassRegistry::getPassRegistry());
+    }
+
+    /// getAdjustedAnalysisPointer - This method is used when a pass implements
+    /// an analysis interface through multiple inheritance.  If needed, it
+    /// should override this to adjust the this pointer as needed for the
+    /// specified pass info.
+    virtual void *getAdjustedAnalysisPointer(AnalysisID PI) {
+      if (PI == &PathProfileInfo::ID)
+        return (PathProfileInfo*)this;
+      return this;
+    }
+
+    virtual const char *getPassName() const {
+      return "NoPathProfileInfo";
+    }
+  };
+}  // End of anonymous namespace
+
+char NoPathProfileInfo::ID = 0;
+// Register this pass...
+INITIALIZE_AG_PASS(NoPathProfileInfo, PathProfileInfo, "no-path-profile",
+                   "No Path Profile Information", false, true, true)
+
+ImmutablePass *llvm::createNoPathProfileInfoPass() { return new NoPathProfileInfo(); }

lib/Analysis/PathProfileVerifier.cpp

@@ -0,0 +1,207 @@
+//===- PathProfileVerifier.cpp --------------------------------*- C++ -*---===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This verifier derives an edge profile file from current path profile
+// information
+//
+//===----------------------------------------------------------------------===//
+#define DEBUG_TYPE "path-profile-verifier"
+
+#include "llvm/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/Analysis/Passes.h"
+#include "llvm/Analysis/ProfileInfoTypes.h"
+#include "llvm/Analysis/PathProfileInfo.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/raw_ostream.h"
+
+#include <stdio.h>
+
+using namespace llvm;
+
+namespace {
+  class PathProfileVerifier : public ModulePass {
+  private:
+    bool runOnModule(Module &M);
+
+  public:
+    static char ID; // Pass identification, replacement for typeid
+    PathProfileVerifier() : ModulePass(ID) {
+      initializePathProfileVerifierPass(*PassRegistry::getPassRegistry());
+    }
+
+
+    virtual const char *getPassName() const {
+      return "Path Profiler Verifier";
+    }
+
+    // The verifier requires the path profile and edge profile.
+    virtual void getAnalysisUsage(AnalysisUsage& AU) const;
+  };
+}
+
+static cl::opt<std::string>
+EdgeProfileFilename("path-profile-verifier-file",
+  cl::init("edgefrompath.llvmprof.out"),
+  cl::value_desc("filename"),
+  cl::desc("Edge profile file generated by -path-profile-verifier"),
+  cl::Hidden);
+
+char PathProfileVerifier::ID = 0;
+INITIALIZE_PASS(PathProfileVerifier, "path-profile-verifier",
+                "Compare the path profile derived edge profile against the "
+                "edge profile.", true, true)
+
+ModulePass *llvm::createPathProfileVerifierPass() {
+  return new PathProfileVerifier();
+}
+
+// The verifier requires the path profile and edge profile.
+void PathProfileVerifier::getAnalysisUsage(AnalysisUsage& AU) const {
+  AU.addRequired<PathProfileInfo>();
+  AU.addPreserved<PathProfileInfo>();
+}
+
+typedef std::map<unsigned, unsigned> DuplicateToIndexMap;
+typedef std::map<BasicBlock*,DuplicateToIndexMap> BlockToDuplicateMap;
+typedef std::map<BasicBlock*,BlockToDuplicateMap> NestedBlockToIndexMap;
+
+// the verifier iterates through each path to gather the total
+// number of edge frequencies
+bool PathProfileVerifier::runOnModule (Module &M) {
+  PathProfileInfo& pathProfileInfo = getAnalysis<PathProfileInfo>();
+
+  // setup a data structure to map path edges which index an
+  // array of edge counters
+  NestedBlockToIndexMap arrayMap;
+  unsigned i = 0;
+  for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F) {
+    if (F->isDeclaration()) continue;
+
+    arrayMap[0][F->begin()][0] = i++;
+
+    for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
+      TerminatorInst *TI = BB->getTerminator();
+
+      unsigned duplicate = 0;
+      BasicBlock* prev = 0;
+      for (unsigned s = 0, e = TI->getNumSuccessors(); s != e;
+           prev = TI->getSuccessor(s), ++s) {
+        if (prev == TI->getSuccessor(s))
+          duplicate++;
+        else duplicate = 0;
+
+        arrayMap[BB][TI->getSuccessor(s)][duplicate] = i++;
+      }
+    }
+  }
+
+  std::vector<unsigned> edgeArray(i);
+
+  // iterate through each path and increment the edge counters as needed
+  for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F) {
+    if (F->isDeclaration()) continue;
+
+    pathProfileInfo.setCurrentFunction(F);
+
+    DEBUG(dbgs() << "function '" << F->getName() << "' ran "
+          << pathProfileInfo.pathsRun()
+          << "/" << pathProfileInfo.getPotentialPathCount()
+          << " potential paths\n");
+
+    for( ProfilePathIterator nextPath = pathProfileInfo.pathBegin(),
+           endPath = pathProfileInfo.pathEnd();
+         nextPath != endPath; nextPath++ ) {
+      ProfilePath* currentPath = nextPath->second;
+
+      ProfilePathEdgeVector* pev = currentPath->getPathEdges();
+      DEBUG(dbgs () << "path #" << currentPath->getNumber() << ": "
+            << currentPath->getCount() << "\n");
+      // setup the entry edge (normally path profiling doens't care about this)
+      if (currentPath->getFirstBlockInPath() == &F->getEntryBlock())
+        edgeArray[arrayMap[0][currentPath->getFirstBlockInPath()][0]]
+          += currentPath->getCount();
+
+      for( ProfilePathEdgeIterator nextEdge = pev->begin(),
+             endEdge = pev->end(); nextEdge != endEdge; nextEdge++ ) {
+        if (nextEdge != pev->begin())
+          DEBUG(dbgs() << " :: ");
+
+        BasicBlock* source = nextEdge->getSource();
+        BasicBlock* target = nextEdge->getTarget();
+        unsigned duplicateNumber = nextEdge->getDuplicateNumber();
+        DEBUG(dbgs () << source->getNameStr() << " --{" << duplicateNumber
+              << "}--> " << target->getNameStr());
+
+        // Ensure all the referenced edges exist
+        // TODO: make this a separate function
+        if( !arrayMap.count(source) ) {
+          errs() << "  error [" << F->getNameStr() << "()]: source '"
+                 << source->getNameStr()
+                 << "' does not exist in the array map.\n";
+        } else if( !arrayMap[source].count(target) ) {
+          errs() << "  error [" << F->getNameStr() << "()]: target '"
+                 << target->getNameStr()
+                 << "' does not exist in the array map.\n";
+        } else if( !arrayMap[source][target].count(duplicateNumber) ) {
+          errs() << "  error [" << F->getNameStr() << "()]: edge "
+                 << source->getNameStr() << " -> " << target->getNameStr()
+                 << " duplicate number " << duplicateNumber
+                 << " does not exist in the array map.\n";
+        } else {
+          edgeArray[arrayMap[source][target][duplicateNumber]]
+            += currentPath->getCount();
+        }
+      }
+
+      DEBUG(errs() << "\n");
+
+      delete pev;
+    }
+  }
+
+  std::string errorInfo;
+  std::string filename = EdgeProfileFilename;
+
+  // Open a handle to the file
+  FILE* edgeFile = fopen(filename.c_str(),"wb");
+
+  if (!edgeFile) {
+    errs() << "error: unable to open file '" << filename << "' for output.\n";
+    return false;
+  }
+
+  errs() << "Generating edge profile '" << filename << "' ...\n";
+
+  // write argument info
+  unsigned type = ArgumentInfo;
+  unsigned num = pathProfileInfo.argList.size();
+  int zeros = 0;
+
+  fwrite(&type,sizeof(unsigned),1,edgeFile);
+  fwrite(&num,sizeof(unsigned),1,edgeFile);
+  fwrite(pathProfileInfo.argList.c_str(),1,num,edgeFile);
+  if (num&3)
+    fwrite(&zeros, 1, 4-(num&3), edgeFile);
+
+  type = EdgeInfo;
+  num = edgeArray.size();
+  fwrite(&type,sizeof(unsigned),1,edgeFile);
+  fwrite(&num,sizeof(unsigned),1,edgeFile);
+
+  // write each edge to the file
+  for( std::vector<unsigned>::iterator s = edgeArray.begin(),
+         e = edgeArray.end(); s != e; s++)
+    fwrite(&*s, sizeof (unsigned), 1, edgeFile);
+
+  fclose (edgeFile);
+
+  return true;
+}

lib/Transforms/Instrumentation/CMakeLists.txt

@@ -2,5 +2,6 @@ add_llvm_library(LLVMInstrumentation
   EdgeProfiling.cpp
   Instrumentation.cpp
   OptimalEdgeProfiling.cpp
+  PathProfiling.cpp
   ProfilingUtils.cpp
   )

lib/Transforms/Instrumentation/EdgeProfiling.cpp

@@ -17,6 +17,7 @@
 //
 //===----------------------------------------------------------------------===//
 #define DEBUG_TYPE "insert-edge-profiling"
+
 #include "ProfilingUtils.h"
 #include "llvm/Module.h"
 #include "llvm/Pass.h"
@@ -100,7 +101,7 @@ bool EdgeProfiler::runOnModule(Module &M) {
           // otherwise insert it in the successor block.
           if (TI->getNumSuccessors() == 1) {
             // Insert counter at the start of the block
-            IncrementCounterInBlock(BB, i++, Counters);
+            IncrementCounterInBlock(BB, i++, Counters, false);
           } else {
             // Insert counter at the start of the block
             IncrementCounterInBlock(TI->getSuccessor(s), i++, Counters);

lib/Transforms/Instrumentation/Instrumentation.cpp

@@ -22,6 +22,7 @@ using namespace llvm;
 void llvm::initializeInstrumentation(PassRegistry &Registry) {
   initializeEdgeProfilerPass(Registry);
   initializeOptimalEdgeProfilerPass(Registry);
+  initializePathProfilerPass(Registry);
 }
 
 /// LLVMInitializeInstrumentation - C binding for

lib/Transforms/Instrumentation/OptimalEdgeProfiling.cpp

@@ -52,12 +52,12 @@ namespace {
 }
 
 char OptimalEdgeProfiler::ID = 0;
-INITIALIZE_PASS_BEGIN(OptimalEdgeProfiler, "insert-optimal-edge-profiling", 
+INITIALIZE_PASS_BEGIN(OptimalEdgeProfiler, "insert-optimal-edge-profiling",
                 "Insert optimal instrumentation for edge profiling",
                 false, false)
 INITIALIZE_PASS_DEPENDENCY(ProfileEstimatorPass)
 INITIALIZE_AG_DEPENDENCY(ProfileInfo)
-INITIALIZE_PASS_END(OptimalEdgeProfiler, "insert-optimal-edge-profiling", 
+INITIALIZE_PASS_END(OptimalEdgeProfiler, "insert-optimal-edge-profiling",
                 "Insert optimal instrumentation for edge profiling",
                 false, false)
 
@@ -132,11 +132,11 @@ bool OptimalEdgeProfiler::runOnModule(Module &M) {
     // Calculate a Maximum Spanning Tree with the edge weights determined by
     // ProfileEstimator. ProfileEstimator also assign weights to the virtual
     // edges (0,entry) and (BB,0) (for blocks with no successors) and this
-    // edges also participate in the maximum spanning tree calculation. 
+    // edges also participate in the maximum spanning tree calculation.
     // The third parameter of MaximumSpanningTree() has the effect that not the
     // actual MST is returned but the edges _not_ in the MST.
 
-    ProfileInfo::EdgeWeights ECs = 
+    ProfileInfo::EdgeWeights ECs =
       getAnalysis<ProfileInfo>(*F).getEdgeWeights(F);
     std::vector<ProfileInfo::EdgeWeight> EdgeVector(ECs.begin(), ECs.end());
     MaximumSpanningTree<BasicBlock> MST (EdgeVector);

lib/Transforms/Instrumentation/ProfilingUtils.cpp

@@ -22,12 +22,13 @@
 #include "llvm/Module.h"
 
 void llvm::InsertProfilingInitCall(Function *MainFn, const char *FnName,
-                                   GlobalValue *Array) {
+                                   GlobalValue *Array,
+                                   PointerType *arrayType) {
   LLVMContext &Context = MainFn->getContext();
-  const Type *ArgVTy = 
+  const Type *ArgVTy =
     PointerType::getUnqual(Type::getInt8PtrTy(Context));
-  const PointerType *UIntPtr =
-        Type::getInt32PtrTy(Context);
+  const PointerType *UIntPtr = arrayType ? arrayType :
+    Type::getInt32PtrTy(Context);
   Module &M = *MainFn->getParent();
   Constant *InitFn = M.getOrInsertFunction(FnName, Type::getInt32Ty(Context),
                                            Type::getInt32Ty(Context),
@@ -71,9 +72,9 @@ void llvm::InsertProfilingInitCall(Function *MainFn, const char *FnName,
   case 2:
     AI = MainFn->arg_begin(); ++AI;
     if (AI->getType() != ArgVTy) {
-      Instruction::CastOps opcode = CastInst::getCastOpcode(AI, false, ArgVTy, 
+      Instruction::CastOps opcode = CastInst::getCastOpcode(AI, false, ArgVTy,
                                                             false);
-      InitCall->setArgOperand(1, 
+      InitCall->setArgOperand(1,
           CastInst::Create(opcode, AI, ArgVTy, "argv.cast", InitCall));
     } else {
       InitCall->setArgOperand(1, AI);
@@ -93,7 +94,7 @@ void llvm::InsertProfilingInitCall(Function *MainFn, const char *FnName,
       }
       opcode = CastInst::getCastOpcode(AI, true,
                                        Type::getInt32Ty(Context), true);
-      InitCall->setArgOperand(0, 
+      InitCall->setArgOperand(0,
           CastInst::Create(opcode, AI, Type::getInt32Ty(Context),
                            "argc.cast", InitCall));
     } else {
@@ -106,9 +107,10 @@ void llvm::InsertProfilingInitCall(Function *MainFn, const char *FnName,
 }
 
 void llvm::IncrementCounterInBlock(BasicBlock *BB, unsigned CounterNum,
-                                   GlobalValue *CounterArray) {
+                                   GlobalValue *CounterArray, bool beginning) {
   // Insert the increment after any alloca or PHI instructions...
-  BasicBlock::iterator InsertPos = BB->getFirstNonPHI();
+  BasicBlock::iterator InsertPos = beginning ? BB->getFirstNonPHI() :
+                BB->getTerminator();
   while (isa<AllocaInst>(InsertPos))
     ++InsertPos;
 
@@ -118,7 +120,7 @@ void llvm::IncrementCounterInBlock(BasicBlock *BB, unsigned CounterNum,
   std::vector<Constant*> Indices(2);
   Indices[0] = Constant::getNullValue(Type::getInt32Ty(Context));
   Indices[1] = ConstantInt::get(Type::getInt32Ty(Context), CounterNum);
-  Constant *ElementPtr = 
+  Constant *ElementPtr =
     ConstantExpr::getGetElementPtr(CounterArray, &Indices[0],
                                           Indices.size());
 

lib/Transforms/Instrumentation/ProfilingUtils.h

@@ -21,11 +21,14 @@ namespace llvm {
   class Function;
   class GlobalValue;
   class BasicBlock;
+  class PointerType;
 
   void InsertProfilingInitCall(Function *MainFn, const char *FnName,
-                               GlobalValue *Arr = 0);
+                               GlobalValue *Arr = 0,
+                               PointerType *arrayType = 0);
   void IncrementCounterInBlock(BasicBlock *BB, unsigned CounterNum,
-                               GlobalValue *CounterArray);
+                               GlobalValue *CounterArray,
+                               bool beginning = true);
 }
 
 #endif

runtime/libprofile/CommonProfiling.c

@@ -2,17 +2,18 @@
 |*
 |*                     The LLVM Compiler Infrastructure
 |*
-|* This file is distributed under the University of Illinois Open Source      
-|* License. See LICENSE.TXT for details.                                      
-|* 
+|* This file is distributed under the University of Illinois Open Source
+|* License. See LICENSE.TXT for details.
+|*
 |*===----------------------------------------------------------------------===*|
-|* 
+|*
 |* This file implements functions used by the various different types of
 |* profiling implementations.
 |*
 \*===----------------------------------------------------------------------===*/
 
 #include "Profiling.h"
+#include <assert.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
@@ -74,26 +75,23 @@ int save_arguments(int argc, const char **argv) {
 }
 
 
-/* write_profiling_data - Write a raw block of profiling counters out to the
- * llvmprof.out file.  Note that we allow programs to be instrumented with
- * multiple different kinds of instrumentation.  For this reason, this function
- * may be called more than once.
+/*
+ * Retrieves the file descriptor for the profile file.
  */
-void write_profiling_data(enum ProfilingType PT, unsigned *Start,
-                          unsigned NumElements) {
+int getOutFile() {
   static int OutFile = -1;
-  int PTy;
-  
-  /* If this is the first time this function is called, open the output file for
-   * appending, creating it if it does not already exist.
+
+  /* If this is the first time this function is called, open the output file
+   * for appending, creating it if it does not already exist.
    */
   if (OutFile == -1) {
-    OutFile = open(OutputFilename, O_CREAT | O_WRONLY | O_APPEND, 0666);
+    OutFile = open(OutputFilename, O_CREAT | O_WRONLY, 0666);
+    lseek(OutFile, 0, SEEK_END); /* O_APPEND prevents seeking */
     if (OutFile == -1) {
       fprintf(stderr, "LLVM profiling runtime: while opening '%s': ",
               OutputFilename);
       perror("");
-      return;
+      return(OutFile);
     }
 
     /* Output the command line arguments to the file. */
@@ -108,10 +106,25 @@ void write_profiling_data(enum ProfilingType PT, unsigned *Start,
         write(OutFile, &Zeros, 4-(SavedArgsLength&3));
     }
   }
- 
+  return(OutFile);
+}
+
+/* write_profiling_data - Write a raw block of profiling counters out to the
+ * llvmprof.out file.  Note that we allow programs to be instrumented with
+ * multiple different kinds of instrumentation.  For this reason, this function
+ * may be called more than once.
+ */
+void write_profiling_data(enum ProfilingType PT, unsigned *Start,
+                          unsigned NumElements) {
+  int PTy;
+  int outFile = getOutFile();
+
   /* Write out this record! */
   PTy = PT;
-  write(OutFile, &PTy, sizeof(int));
-  write(OutFile, &NumElements, sizeof(unsigned));
-  write(OutFile, Start, NumElements*sizeof(unsigned));
+  if( write(outFile, &PTy, sizeof(int)) < 0 ||
+      write(outFile, &NumElements, sizeof(unsigned)) < 0 ||
+      write(outFile, Start, NumElements*sizeof(unsigned)) < 0 ) {
+    fprintf(stderr,"error: unable to write to output file.");
+    exit(0);
+  }
 }

runtime/libprofile/PathProfiling.c

@@ -0,0 +1,266 @@
+/*===-- PathProfiling.c - Support library for path profiling --------------===*\
+|*
+|*                     The LLVM Compiler Infrastructure
+|*
+|* This file is distributed under the University of Illinois Open Source
+|* License. See LICENSE.TXT for details.
+|*
+|*===----------------------------------------------------------------------===*|
+|*
+|* This file implements the call back routines for the path profiling
+|* instrumentation pass.  This should be used with the -insert-path-profiling
+|* LLVM pass.
+|*
+\*===----------------------------------------------------------------------===*/
+
+#include "Profiling.h"
+#include "llvm/Analysis/ProfileInfoTypes.h"
+#include <sys/types.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <stdio.h>
+
+/* note that this is used for functions with large path counts,
+         but it is unlikely those paths will ALL be executed */
+#define ARBITRARY_HASH_BIN_COUNT 100
+
+typedef struct pathHashEntry_s {
+  uint32_t pathNumber;
+  uint32_t pathCount;
+  struct pathHashEntry_s* next;
+} pathHashEntry_t;
+
+typedef struct pathHashTable_s {
+  pathHashEntry_t* hashBins[ARBITRARY_HASH_BIN_COUNT];
+  uint32_t pathCounts;
+} pathHashTable_t;
+
+typedef struct {
+  enum ProfilingStorageType type;
+  uint32_t size;
+  void* array;
+} ftEntry_t;
+
+/* pointer to the function table allocated in the instrumented program */
+ftEntry_t* ft;
+uint32_t ftSize;
+
+/* write an array table to file */
+void writeArrayTable(uint32_t fNumber, ftEntry_t* ft, uint32_t* funcCount) {
+  int outFile = getOutFile();
+  uint32_t arrayHeaderLocation = 0;
+  uint32_t arrayCurrentLocation = 0;
+  uint32_t arrayIterator = 0;
+  uint32_t functionUsed = 0;
+  uint32_t pathCounts = 0;
+
+  /* look through each entry in the array to determine whether the function
+     was executed at all */
+  for( arrayIterator = 0; arrayIterator < ft->size; arrayIterator++ ) {
+    uint32_t pc = ((uint32_t*)ft->array)[arrayIterator];
+
+    /* was this path executed? */
+    if( pc ) {
+      PathProfileTableEntry pte;
+      pte.pathNumber = arrayIterator;
+      pte.pathCounter = pc;
+      pathCounts++;
+
+      /* one-time initialization stuff */
+      if(!functionUsed) {
+        arrayHeaderLocation = lseek(outFile, 0, SEEK_CUR);
+        lseek(outFile, sizeof(PathProfileHeader), SEEK_CUR);
+        functionUsed = 1;
+        (*funcCount)++;
+      }
+
+      /* write path data */
+      if (write(outFile, &pte, sizeof(PathProfileTableEntry)) < 0) {
+        fprintf(stderr, "error: unable to write path entry to output file.\n");
+        return;
+      }
+    }
+  }
+
+  /* If this function was executed, write the header */
+  if( functionUsed ) {
+    PathProfileHeader fHeader;
+    fHeader.fnNumber = fNumber;
+    fHeader.numEntries = pathCounts;
+
+    arrayCurrentLocation = lseek(outFile, 0, SEEK_CUR);
+    lseek(outFile, arrayHeaderLocation, SEEK_SET);
+
+    if (write(outFile, &fHeader, sizeof(PathProfileHeader)) < 0) {
+      fprintf(stderr,
+              "error: unable to write function header to output file.\n");
+      return;
+    }
+
+    lseek(outFile, arrayCurrentLocation, SEEK_SET);
+  }
+}
+
+inline uint32_t hash (uint32_t key) {
+  /* this may benifit from a proper hash function */
+  return key%ARBITRARY_HASH_BIN_COUNT;
+}
+
+/* output a specific function's hash table to the profile file */
+void writeHashTable(uint32_t functionNumber, pathHashTable_t* hashTable) {
+  int outFile = getOutFile();
+  PathProfileHeader header;
+  uint32_t i;
+
+  header.fnNumber = functionNumber;
+  header.numEntries = hashTable->pathCounts;
+
+  if (write(outFile, &header, sizeof(PathProfileHeader)) < 0) {
+    fprintf(stderr, "error: unable to write function header to output file.\n");
+    return;
+  }
+
+  for (i = 0; i < ARBITRARY_HASH_BIN_COUNT; i++) {
+    pathHashEntry_t* hashEntry = hashTable->hashBins[i];
+
+    while (hashEntry) {
+      pathHashEntry_t* temp;
+
+      PathProfileTableEntry pte;
+      pte.pathNumber = hashEntry->pathNumber;
+      pte.pathCounter = hashEntry->pathCount;
+
+      if (write(outFile, &pte, sizeof(PathProfileTableEntry)) < 0) {
+        fprintf(stderr, "error: unable to write path entry to output file.\n");
+        return;
+      }
+
+      temp = hashEntry;
+      hashEntry = hashEntry->next;
+      free (temp);
+
+    }
+  }
+}
+
+/* Return a pointer to this path's specific path counter */
+inline uint32_t* getPathCounter(uint32_t functionNumber, uint32_t pathNumber) {
+  pathHashTable_t* hashTable;
+  pathHashEntry_t* hashEntry;
+  uint32_t index = hash(pathNumber);
+
+  if( ft[functionNumber-1].array == 0)
+    ft[functionNumber-1].array = calloc(sizeof(pathHashTable_t), 1);
+
+  hashTable = (pathHashTable_t*)((ftEntry_t*)ft)[functionNumber-1].array;
+  hashEntry = hashTable->hashBins[index];
+
+  while (hashEntry) {
+    if (hashEntry->pathNumber == pathNumber) {
+      return &hashEntry->pathCount;
+    }
+
+    hashEntry = hashEntry->next;
+  }
+
+  hashEntry = malloc(sizeof(pathHashEntry_t));
+  hashEntry->pathNumber = pathNumber;
+  hashEntry->pathCount = 0;
+  hashEntry->next = hashTable->hashBins[index];
+  hashTable->hashBins[index] = hashEntry;
+  hashTable->pathCounts++;
+  return &hashEntry->pathCount;
+}
+
+/* Increment a specific path's count */
+void llvm_increment_path_count (uint32_t functionNumber, uint32_t pathNumber) {
+  uint32_t* pathCounter = getPathCounter(functionNumber, pathNumber);
+  if( *pathCounter < 0xffffffff )
+    (*pathCounter)++;
+}
+
+/* Increment a specific path's count */
+void llvm_decrement_path_count (uint32_t functionNumber, uint32_t pathNumber) {
+  uint32_t* pathCounter = getPathCounter(functionNumber, pathNumber);
+  (*pathCounter)--;
+}
+
+/*
+ * Writes out a path profile given a function table, in the following format.
+ *
+ *
+ *      | <-- 32 bits --> |
+ *      +-----------------+-----------------+
+ * 0x00 | profileType     | functionCount   |
+ *      +-----------------+-----------------+
+ * 0x08 | functionNum     | profileEntries  |  // function 1
+ *      +-----------------+-----------------+
+ * 0x10 | pathNumber      | pathCounter     |  // entry 1.1
+ *      +-----------------+-----------------+
+ * 0x18 | pathNumber      | pathCounter     |  // entry 1.2
+ *      +-----------------+-----------------+
+ *  ... |       ...       |       ...       |  // entry 1.n
+ *      +-----------------+-----------------+
+ *  ... | functionNum     | profileEntries  |  // function 2
+ *      +-----------------+-----------------+
+ *  ... | pathNumber      | pathCounter     |  // entry 2.1
+ *      +-----------------+-----------------+
+ *  ... | pathNumber      | pathCounter     |  // entry 2.2
+ *      +-----------------+-----------------+
+ *  ... |       ...       |       ...       |  // entry 2.n
+ *      +-----------------+-----------------+
+ *
+ */
+static void pathProfAtExitHandler() {
+  int outFile = getOutFile();
+  uint32_t i;
+  uint32_t header[2] = { PathInfo, 0 };
+  uint32_t headerLocation;
+  uint32_t currentLocation;
+
+  /* skip over the header for now */
+  headerLocation = lseek(outFile, 0, SEEK_CUR);
+  lseek(outFile, 2*sizeof(uint32_t), SEEK_CUR);
+
+  /* Iterate through each function */
+  for( i = 0; i < ftSize; i++ ) {
+    if( ft[i].type == ProfilingArray ) {
+      writeArrayTable(i+1,&ft[i],header + 1);
+
+    } else if( ft[i].type == ProfilingHash ) {
+      /* If the hash exists, write it to file */
+      if( ft[i].array ) {
+        writeHashTable(i+1,ft[i].array);
+        header[1]++;
+        free(ft[i].array);
+      }
+    }
+  }
+
+  /* Setup and write the path profile header */
+  currentLocation = lseek(outFile, 0, SEEK_CUR);
+  lseek(outFile, headerLocation, SEEK_SET);
+
+  if (write(outFile, header, sizeof(header)) < 0) {
+    fprintf(stderr,
+            "error: unable to write path profile header to output file.\n");
+    return;
+  }
+
+  lseek(outFile, currentLocation, SEEK_SET);
+}
+/* llvm_start_path_profiling - This is the main entry point of the path
+ * profiling library.  It is responsible for setting up the atexit handler.
+ */
+int llvm_start_path_profiling(int argc, const char** argv,
+                              void* functionTable, uint32_t numElements) {
+  int Ret = save_arguments(argc, argv);
+  ft = functionTable;
+  ftSize = numElements;
+  atexit(pathProfAtExitHandler);
+
+  return Ret;
+}

runtime/libprofile/Profiling.h

@@ -1,9 +1,9 @@
-/*===-- Profiling.h - Profiling support library support routines --*- C -*-===*\
+/*===-- Profiling.h - Profiling support library support routines ----------===*\
 |*
 |*                     The LLVM Compiler Infrastructure
 |*
-|* This file is distributed under the University of Illinois Open Source      
-|* License. See LICENSE.TXT for details.                                      
+|* This file is distributed under the University of Illinois Open Source
+|* License. See LICENSE.TXT for details.
 |*
 |*===----------------------------------------------------------------------===*|
 |*
@@ -22,6 +22,11 @@
  */
 int save_arguments(int argc, const char **argv);
 
+/*
+ * Retrieves the file descriptor for the profile file.
+ */
+int getOutFile();
+
 /* write_profiling_data - Write out a typed packet of profiling data to the
  * current output file.
  */

runtime/libprofile/libprofile.exports

@@ -1,4 +1,7 @@
 llvm_start_edge_profiling
 llvm_start_opt_edge_profiling
+llvm_start_path_profiling
 llvm_start_basic_block_tracing
 llvm_trace_basic_block
+llvm_increment_path_count
+llvm_decrement_path_count