File depends on DSA, moved to lib/Analysis/DataStructure

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14325 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 0 insertions, 495 deletions

diff --git a/lib/Transforms/IPO/Parallelize.cpp b/lib/Transforms/IPO/Parallelize.cpp
deleted file mode 100644
index 46bb72f836..0000000000
--- a/lib/Transforms/IPO/Parallelize.cpp
+++ /dev/null
@@ -1,495 +0,0 @@
-//===- Parallelize.cpp - Auto parallelization using DS Graphs -------------===//
-// 
-//                     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.
-// 
-//===----------------------------------------------------------------------===//
-//
-// This file implements a pass that automatically parallelizes a program,
-// using the Cilk multi-threaded runtime system to execute parallel code.
-// 
-// The pass uses the Program Dependence Graph (class PDGIterator) to
-// identify parallelizable function calls, i.e., calls whose instances
-// can be executed in parallel with instances of other function calls.
-// (In the future, this should also execute different instances of the same
-// function call in parallel, but that requires parallelizing across
-// loop iterations.)
-//
-// The output of the pass is LLVM code with:
-// (1) all parallelizable functions renamed to flag them as parallelizable;
-// (2) calls to a sync() function introduced at synchronization points.
-// The CWriter recognizes these functions and inserts the appropriate Cilk
-// keywords when writing out C code.  This C code must be compiled with cilk2c.
-// 
-// Current algorithmic limitations:
-// -- no array dependence analysis
-// -- no parallelization for function calls in different loop iterations
-//    (except in unlikely trivial cases)
-//
-// Limitations of using Cilk:
-// -- No parallelism within a function body, e.g., in a loop;
-// -- Simplistic synchronization model requiring all parallel threads 
-//    created within a function to block at a sync().
-// -- Excessive overhead at "spawned" function calls, which has no benefit
-//    once all threads are busy (especially common when the degree of
-//    parallelism is low).
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/DerivedTypes.h"
-#include "llvm/Instructions.h"
-#include "llvm/Module.h"
-#include "llvm/Analysis/PgmDependenceGraph.h"
-#include "llvm/Analysis/DataStructure.h"
-#include "llvm/Analysis/DSGraph.h"
-#include "llvm/Support/InstVisitor.h"
-#include "llvm/Transforms/Utils/Local.h"
-#include "Support/Statistic.h"
-#include "Support/STLExtras.h"
-#include "Support/hash_set"
-#include "Support/hash_map"
-#include <functional>
-#include <algorithm>
-using namespace llvm;
-
-//---------------------------------------------------------------------------- 
-// Global constants used in marking Cilk functions and function calls.
-//---------------------------------------------------------------------------- 
-
-static const char * const CilkSuffix = ".llvm2cilk";
-static const char * const DummySyncFuncName = "__sync.llvm2cilk";
-
-//---------------------------------------------------------------------------- 
-// Routines to identify Cilk functions, calls to Cilk functions, and syncs.
-//---------------------------------------------------------------------------- 
-
-static bool isCilk(const Function& F) {
-  return (F.getName().rfind(CilkSuffix) ==
-          F.getName().size() - std::strlen(CilkSuffix));
-}
-
-static bool isCilkMain(const Function& F) {
-  return F.getName() == "main" + std::string(CilkSuffix);
-}
-
-
-static bool isCilk(const CallInst& CI) {
-  return CI.getCalledFunction() && isCilk(*CI.getCalledFunction());
-}
-
-static bool isSync(const CallInst& CI) { 
-  return CI.getCalledFunction() &&
-         CI.getCalledFunction()->getName() == DummySyncFuncName;
-}
-
-
-//---------------------------------------------------------------------------- 
-// class Cilkifier
-//
-// Code generation pass that transforms code to identify where Cilk keywords
-// should be inserted.  This relies on `llvm-dis -c' to print out the keywords.
-//---------------------------------------------------------------------------- 
-class Cilkifier: public InstVisitor<Cilkifier> {
-  Function* DummySyncFunc;
-
-  // Data used when transforming each function.
-  hash_set<const Instruction*>  stmtsVisited;    // Flags for recursive DFS
-  hash_map<const CallInst*, hash_set<CallInst*> > spawnToSyncsMap;
-
-  // Input data for the transformation.
-  const hash_set<Function*>*    cilkFunctions;   // Set of parallel functions
-  PgmDependenceGraph*           depGraph;
-
-  void          DFSVisitInstr   (Instruction* I,
-                                 Instruction* root,
-                                 hash_set<const Instruction*>& depsOfRoot);
-
-public:
-  /*ctor*/      Cilkifier       (Module& M);
-
-  // Transform a single function including its name, its call sites, and syncs
-  // 
-  void          TransformFunc   (Function* F,
-                                 const hash_set<Function*>& cilkFunctions,
-                                 PgmDependenceGraph&  _depGraph);
-
-  // The visitor function that does most of the hard work, via DFSVisitInstr
-  // 
-  void visitCallInst(CallInst& CI);
-};
-
-
-Cilkifier::Cilkifier(Module& M) {
-  // create the dummy Sync function and add it to the Module
-  DummySyncFunc = M.getOrInsertFunction(DummySyncFuncName, Type::VoidTy, 0);
-}
-
-void Cilkifier::TransformFunc(Function* F,
-                              const hash_set<Function*>& _cilkFunctions,
-                              PgmDependenceGraph& _depGraph) {
-  // Memoize the information for this function
-  cilkFunctions = &_cilkFunctions;
-  depGraph = &_depGraph;
-
-  // Add the marker suffix to the Function name
-  // This should automatically mark all calls to the function also!
-  F->setName(F->getName() + CilkSuffix);
-
-  // Insert sync operations for each separate spawn
-  visit(*F);
-
-  // Now traverse the CFG in rPostorder and eliminate redundant syncs, i.e.,
-  // two consecutive sync's on a straight-line path with no intervening spawn.
-  
-}
-
-
-void Cilkifier::DFSVisitInstr(Instruction* I,
-                              Instruction* root,
-                              hash_set<const Instruction*>& depsOfRoot)
-{
-  assert(stmtsVisited.find(I) == stmtsVisited.end());
-  stmtsVisited.insert(I);
-
-  // If there is a dependence from root to I, insert Sync and return
-  if (depsOfRoot.find(I) != depsOfRoot.end()) {
-    // Insert a sync before I and stop searching along this path.
-    // If I is a Phi instruction, the dependence can only be an SSA dep.
-    // and we need to insert the sync in the predecessor on the appropriate
-    // incoming edge!
-    CallInst* syncI = 0;
-    if (PHINode* phiI = dyn_cast<PHINode>(I)) {
-      // check all operands of the Phi and insert before each one
-      for (unsigned i = 0, N = phiI->getNumIncomingValues(); i < N; ++i)
-        if (phiI->getIncomingValue(i) == root)
-          syncI = new CallInst(DummySyncFunc, std::vector<Value*>(), "",
-                               phiI->getIncomingBlock(i)->getTerminator());
-    } else
-      syncI = new CallInst(DummySyncFunc, std::vector<Value*>(), "", I);
-
-    // Remember the sync for each spawn to eliminate redundant ones later
-    spawnToSyncsMap[cast<CallInst>(root)].insert(syncI);
-
-    return;
-  }
-
-  // else visit unvisited successors
-  if (BranchInst* brI = dyn_cast<BranchInst>(I)) {
-    // visit first instruction in each successor BB
-    for (unsigned i = 0, N = brI->getNumSuccessors(); i < N; ++i)
-      if (stmtsVisited.find(&brI->getSuccessor(i)->front())
-          == stmtsVisited.end())
-        DFSVisitInstr(&brI->getSuccessor(i)->front(), root, depsOfRoot);
-  } else
-    if (Instruction* nextI = I->getNext())
-      if (stmtsVisited.find(nextI) == stmtsVisited.end())
-        DFSVisitInstr(nextI, root, depsOfRoot);
-}
-
-
-void Cilkifier::visitCallInst(CallInst& CI)
-{
-  assert(CI.getCalledFunction() != 0 && "Only direct calls can be spawned.");
-  if (cilkFunctions->find(CI.getCalledFunction()) == cilkFunctions->end())
-    return;                             // not a spawn
-
-  // Find all the outgoing memory dependences.
-  hash_set<const Instruction*> depsOfRoot;
-  for (PgmDependenceGraph::iterator DI =
-         depGraph->outDepBegin(CI, MemoryDeps); ! DI.fini(); ++DI)
-    depsOfRoot.insert(&DI->getSink()->getInstr());
-
-  // Now find all outgoing SSA dependences to the eventual non-Phi users of
-  // the call value (i.e., direct users that are not phis, and for any
-  // user that is a Phi, direct non-Phi users of that Phi, and recursively).
-  std::vector<const PHINode*> phiUsers;
-  hash_set<const PHINode*> phisSeen;    // ensures we don't visit a phi twice
-  for (Value::use_iterator UI=CI.use_begin(), UE=CI.use_end(); UI != UE; ++UI)
-    if (const PHINode* phiUser = dyn_cast<PHINode>(*UI)) {
-      if (phisSeen.find(phiUser) == phisSeen.end()) {
-        phiUsers.push_back(phiUser);
-        phisSeen.insert(phiUser);
-      }
-    }
-    else
-      depsOfRoot.insert(cast<Instruction>(*UI));
-
-  // Now we've found the non-Phi users and immediate phi users.
-  // Recursively walk the phi users and add their non-phi users.
-  for (const PHINode* phiUser; !phiUsers.empty(); phiUsers.pop_back()) {
-    phiUser = phiUsers.back();
-    for (Value::use_const_iterator UI=phiUser->use_begin(),
-           UE=phiUser->use_end(); UI != UE; ++UI)
-      if (const PHINode* pn = dyn_cast<PHINode>(*UI)) {
-        if (phisSeen.find(pn) == phisSeen.end()) {
-          phiUsers.push_back(pn);
-          phisSeen.insert(pn);
-        }
-      } else
-        depsOfRoot.insert(cast<Instruction>(*UI));
-  }
-
-  // Walk paths of the CFG starting at the call instruction and insert
-  // one sync before the first dependence on each path, if any.
-  if (! depsOfRoot.empty()) {
-    stmtsVisited.clear();             // start a new DFS for this CallInst
-    assert(CI.getNext() && "Call instruction cannot be a terminator!");
-    DFSVisitInstr(CI.getNext(), &CI, depsOfRoot);
-  }
-
-  // Now, eliminate all users of the SSA value of the CallInst, i.e., 
-  // if the call instruction returns a value, delete the return value
-  // register and replace it by a stack slot.
-  if (CI.getType() != Type::VoidTy)
-    DemoteRegToStack(CI);
-}
-
-
-//---------------------------------------------------------------------------- 
-// class FindParallelCalls
-//
-// Find all CallInst instructions that have at least one other CallInst
-// that is independent.  These are the instructions that can produce
-// useful parallelism.
-//---------------------------------------------------------------------------- 
-
-class FindParallelCalls : public InstVisitor<FindParallelCalls> {
-  typedef hash_set<CallInst*>           DependentsSet;
-  typedef DependentsSet::iterator       Dependents_iterator;
-  typedef DependentsSet::const_iterator Dependents_const_iterator;
-
-  PgmDependenceGraph& depGraph;         // dependence graph for the function
-  hash_set<Instruction*> stmtsVisited;  // flags for DFS walk of depGraph
-  hash_map<CallInst*, bool > completed; // flags marking if a CI is done
-  hash_map<CallInst*, DependentsSet> dependents; // dependent CIs for each CI
-
-  void VisitOutEdges(Instruction*   I,
-                     CallInst*      root,
-                     DependentsSet& depsOfRoot);
-
-  FindParallelCalls(const FindParallelCalls &); // DO NOT IMPLEMENT
-  void operator=(const FindParallelCalls&);     // DO NOT IMPLEMENT
-public:
-  std::vector<CallInst*> parallelCalls;
-
-public:
-  /*ctor*/      FindParallelCalls       (Function& F, PgmDependenceGraph& DG);
-  void          visitCallInst           (CallInst& CI);
-};
-
-
-FindParallelCalls::FindParallelCalls(Function& F,
-                                     PgmDependenceGraph& DG)
-  : depGraph(DG)
-{
-  // Find all CallInsts reachable from each CallInst using a recursive DFS
-  visit(F);
-
-  // Now we've found all CallInsts reachable from each CallInst.
-  // Find those CallInsts that are parallel with at least one other CallInst
-  // by counting total inEdges and outEdges.
-  unsigned long totalNumCalls = completed.size();
-
-  if (totalNumCalls == 1) {
-    // Check first for the special case of a single call instruction not
-    // in any loop.  It is not parallel, even if it has no dependences
-    // (this is why it is a special case).
-    //
-    // FIXME:
-    // THIS CASE IS NOT HANDLED RIGHT NOW, I.E., THERE IS NO
-    // PARALLELISM FOR CALLS IN DIFFERENT ITERATIONS OF A LOOP.
-    return;
-  }
-
-  hash_map<CallInst*, unsigned long> numDeps;
-  for (hash_map<CallInst*, DependentsSet>::iterator II = dependents.begin(),
-         IE = dependents.end(); II != IE; ++II) {
-    CallInst* fromCI = II->first;
-    numDeps[fromCI] += II->second.size();
-    for (Dependents_iterator DI = II->second.begin(), DE = II->second.end();
-         DI != DE; ++DI)
-      numDeps[*DI]++;                 // *DI can be reached from II->first
-  }
-
-  for (hash_map<CallInst*, DependentsSet>::iterator
-         II = dependents.begin(), IE = dependents.end(); II != IE; ++II)
-
-    // FIXME: Remove "- 1" when considering parallelism in loops
-    if (numDeps[II->first] < totalNumCalls - 1)
-      parallelCalls.push_back(II->first);
-}
-
-
-void FindParallelCalls::VisitOutEdges(Instruction* I,
-                                      CallInst* root,
-                                      DependentsSet& depsOfRoot)
-{
-  assert(stmtsVisited.find(I) == stmtsVisited.end() && "Stmt visited twice?");
-  stmtsVisited.insert(I);
-
-  if (CallInst* CI = dyn_cast<CallInst>(I))
-    // FIXME: Ignoring parallelism in a loop.  Here we're actually *ignoring*
-    // a self-dependence in order to get the count comparison right above.
-    // When we include loop parallelism, self-dependences should be included.
-    if (CI != root) {
-      // CallInst root has a path to CallInst I and any calls reachable from I
-      depsOfRoot.insert(CI);
-      if (completed[CI]) {
-        // We have already visited I so we know all nodes it can reach!
-        DependentsSet& depsOfI = dependents[CI];
-        depsOfRoot.insert(depsOfI.begin(), depsOfI.end());
-        return;
-      }
-    }
-
-  // If we reach here, we need to visit all children of I
-  for (PgmDependenceGraph::iterator DI = depGraph.outDepBegin(*I);
-       ! DI.fini(); ++DI) {
-    Instruction* sink = &DI->getSink()->getInstr();
-    if (stmtsVisited.find(sink) == stmtsVisited.end())
-      VisitOutEdges(sink, root, depsOfRoot);
-  }
-}
-
-
-void FindParallelCalls::visitCallInst(CallInst& CI) {
-  if (completed[&CI])
-    return;
-  stmtsVisited.clear();                      // clear flags to do a fresh DFS
-
-  // Visit all children of CI using a recursive walk through dep graph
-  DependentsSet& depsOfRoot = dependents[&CI];
-  for (PgmDependenceGraph::iterator DI = depGraph.outDepBegin(CI);
-       ! DI.fini(); ++DI) {
-    Instruction* sink = &DI->getSink()->getInstr();
-    if (stmtsVisited.find(sink) == stmtsVisited.end())
-      VisitOutEdges(sink, &CI, depsOfRoot);
-  }
-
-  completed[&CI] = true;
-}
-
-
-//---------------------------------------------------------------------------- 
-// class Parallelize
-//
-// (1) Find candidate parallel functions: any function F s.t.
-//       there is a call C1 to the function F that is followed or preceded
-//       by at least one other call C2 that is independent of this one
-//       (i.e., there is no dependence path from C1 to C2 or C2 to C1)
-// (2) Label such a function F as a cilk function.
-// (3) Convert every call to F to a spawn
-// (4) For every function X, insert sync statements so that
-//        every spawn is postdominated by a sync before any statements
-//        with a data dependence to/from the call site for the spawn
-// 
-//---------------------------------------------------------------------------- 
-
-namespace {
-  class Parallelize: public Pass {
-  public:
-    /// Driver functions to transform a program
-    ///
-    bool run(Module& M);
-
-    /// getAnalysisUsage - Modifies extensively so preserve nothing.
-    /// Uses the DependenceGraph and the Top-down DS Graph (only to find
-    /// all functions called via an indirect call).
-    ///
-    void getAnalysisUsage(AnalysisUsage &AU) const {
-      AU.addRequired<TDDataStructures>();
-      AU.addRequired<MemoryDepAnalysis>();  // force this not to be released
-      AU.addRequired<PgmDependenceGraph>(); // because it is needed by this
-    }
-  };
-
-  RegisterOpt<Parallelize> X("parallel", "Parallelize program using Cilk");
-}
-
-
-bool Parallelize::run(Module& M) {
-  hash_set<Function*> parallelFunctions;
-  hash_set<Function*> safeParallelFunctions;
-  hash_set<const GlobalValue*> indirectlyCalled;
-
-  // If there is no main (i.e., for an incomplete program), we can do nothing.
-  // If there is a main, mark main as a parallel function.
-  Function* mainFunc = M.getMainFunction();
-  if (!mainFunc)
-    return false;
-
-  // (1) Find candidate parallel functions and mark them as Cilk functions
-  for (Module::iterator FI = M.begin(), FE = M.end(); FI != FE; ++FI)
-    if (! FI->isExternal()) {
-      Function* F = FI;
-      DSGraph& tdg = getAnalysis<TDDataStructures>().getDSGraph(*F);
-
-      // All the hard analysis work gets done here!
-      FindParallelCalls finder(*F,
-                              getAnalysis<PgmDependenceGraph>().getGraph(*F));
-                      /* getAnalysis<MemoryDepAnalysis>().getGraph(*F)); */
-
-      // Now we know which call instructions are useful to parallelize.
-      // Remember those callee functions.
-      for (std::vector<CallInst*>::iterator
-             CII = finder.parallelCalls.begin(),
-             CIE = finder.parallelCalls.end(); CII != CIE; ++CII) {
-        // Check if this is a direct call...
-        if ((*CII)->getCalledFunction() != NULL) {
-          // direct call: if this is to a non-external function,
-          // mark it as a parallelizable function
-          if (! (*CII)->getCalledFunction()->isExternal())
-            parallelFunctions.insert((*CII)->getCalledFunction());
-        } else {
-          // Indirect call: mark all potential callees as bad
-          std::vector<GlobalValue*> callees =
-            tdg.getNodeForValue((*CII)->getCalledValue())
-            .getNode()->getGlobals();
-          indirectlyCalled.insert(callees.begin(), callees.end());
-        }
-      }
-    }
-
-  // Remove all indirectly called functions from the list of Cilk functions.
-  for (hash_set<Function*>::iterator PFI = parallelFunctions.begin(),
-         PFE = parallelFunctions.end(); PFI != PFE; ++PFI)
-    if (indirectlyCalled.count(*PFI) == 0)
-      safeParallelFunctions.insert(*PFI);
-
-#undef CAN_USE_BIND1ST_ON_REFERENCE_TYPE_ARGS
-#ifdef CAN_USE_BIND1ST_ON_REFERENCE_TYPE_ARGS
-  // Use this indecipherable STLese because erase invalidates iterators.
-  // Otherwise we have to copy sets as above.
-  hash_set<Function*>::iterator extrasBegin = 
-    std::remove_if(parallelFunctions.begin(), parallelFunctions.end(),
-                   compose1(std::bind2nd(std::greater<int>(), 0),
-                            bind_obj(&indirectlyCalled,
-                                     &hash_set<const GlobalValue*>::count)));
-  parallelFunctions.erase(extrasBegin, parallelFunctions.end());
-#endif
-
-  // If there are no parallel functions, we can just give up.
-  if (safeParallelFunctions.empty())
-    return false;
-
-  // Add main as a parallel function since Cilk requires this.
-  safeParallelFunctions.insert(mainFunc);
-
-  // (2,3) Transform each Cilk function and all its calls simply by
-  //     adding a unique suffix to the function name.
-  //     This should identify both functions and calls to such functions
-  //     to the code generator.
-  // (4) Also, insert calls to sync at appropriate points.
-  Cilkifier cilkifier(M);
-  for (hash_set<Function*>::iterator CFI = safeParallelFunctions.begin(),
-         CFE = safeParallelFunctions.end(); CFI != CFE; ++CFI) {
-    cilkifier.TransformFunc(*CFI, safeParallelFunctions,
-                           getAnalysis<PgmDependenceGraph>().getGraph(**CFI));
-    /* getAnalysis<MemoryDepAnalysis>().getGraph(**CFI)); */
-  }
-
-  return true;
-}
-