path: root/lib/VMCore/Pass.cpp

//===- Pass.cpp - LLVM Pass Infrastructure Impementation ------------------===//
//
// This file implements the LLVM Pass infrastructure.  It is primarily
// responsible with ensuring that passes are executed and batched together
// optimally.
//
//===----------------------------------------------------------------------===//

#include "llvm/PassManager.h"
#include "PassManagerT.h"         // PassManagerT implementation
#include "llvm/Module.h"
#include "Support/STLExtras.h"
#include "Support/TypeInfo.h"
#include <stdio.h>
#include <sys/resource.h>
#include <sys/unistd.h>
#include <set>

// IncludeFile - Stub function used to help linking out.
IncludeFile::IncludeFile(void*) {}

//===----------------------------------------------------------------------===//
//   AnalysisID Class Implementation
//

static std::vector<const PassInfo*> CFGOnlyAnalyses;

void RegisterPassBase::setPreservesCFG() {
  CFGOnlyAnalyses.push_back(PIObj);
}

//===----------------------------------------------------------------------===//
//   AnalysisResolver Class Implementation
//

void AnalysisResolver::setAnalysisResolver(Pass *P, AnalysisResolver *AR) {
  assert(P->Resolver == 0 && "Pass already in a PassManager!");
  P->Resolver = AR;
}

//===----------------------------------------------------------------------===//
//   AnalysisUsage Class Implementation
//

// preservesCFG - This function should be called to by the pass, iff they do
// not:
//
//  1. Add or remove basic blocks from the function
//  2. Modify terminator instructions in any way.
//
// This function annotates the AnalysisUsage info object to say that analyses
// that only depend on the CFG are preserved by this pass.
//
void AnalysisUsage::preservesCFG() {
  // Since this transformation doesn't modify the CFG, it preserves all analyses
  // that only depend on the CFG (like dominators, loop info, etc...)
  //
  Preserved.insert(Preserved.end(),
                   CFGOnlyAnalyses.begin(), CFGOnlyAnalyses.end());
}


//===----------------------------------------------------------------------===//
// PassManager implementation - The PassManager class is a simple Pimpl class
// that wraps the PassManagerT template.
//
PassManager::PassManager() : PM(new PassManagerT<Module>()) {}
PassManager::~PassManager() { delete PM; }
void PassManager::add(Pass *P) { PM->add(P); }
bool PassManager::run(Module &M) { return PM->run(M); }


//===----------------------------------------------------------------------===//
// TimingInfo Class - This class is used to calculate information about the
// amount of time each pass takes to execute.  This only happens with
// -time-passes is enabled on the command line.
//
static cl::opt<bool>
EnableTiming("time-passes",
            cl::desc("Time each pass, printing elapsed time for each on exit"));

static TimeRecord getTimeRecord() {
  static unsigned long PageSize = 0;

  if (PageSize == 0) {
#ifdef _SC_PAGE_SIZE
    PageSize = sysconf(_SC_PAGE_SIZE);
#else
#ifdef _SC_PAGESIZE
    PageSize = sysconf(_SC_PAGESIZE);
#else
    PageSize = getpagesize();
#endif
#endif
  }

  struct rusage RU;
  struct timeval T;
  gettimeofday(&T, 0);
  if (getrusage(RUSAGE_SELF, &RU)) {
    perror("getrusage call failed: -time-passes info incorrect!");
  }

  TimeRecord Result;
  Result.Elapsed    =           T.tv_sec +           T.tv_usec/1000000.0;
  Result.UserTime   = RU.ru_utime.tv_sec + RU.ru_utime.tv_usec/1000000.0;
  Result.SystemTime = RU.ru_stime.tv_sec + RU.ru_stime.tv_usec/1000000.0;
  Result.MaxRSS = RU.ru_maxrss*PageSize;

  return Result;
}

bool TimeRecord::operator<(const TimeRecord &TR) const {
  // Primary sort key is User+System time
  if (UserTime+SystemTime < TR.UserTime+TR.SystemTime)
    return true;
  if (UserTime+SystemTime > TR.UserTime+TR.SystemTime)
    return false;

  // Secondary sort key is Wall Time
  return Elapsed < TR.Elapsed;
}

void TimeRecord::passStart(const TimeRecord &T) {
  Elapsed    -= T.Elapsed;
  UserTime   -= T.UserTime;
  SystemTime -= T.SystemTime;
  RSSTemp     = T.MaxRSS;
}

void TimeRecord::passEnd(const TimeRecord &T) {
  Elapsed    += T.Elapsed;
  UserTime   += T.UserTime;
  SystemTime += T.SystemTime;
  RSSTemp     = T.MaxRSS - RSSTemp;
  MaxRSS      = std::max(MaxRSS, RSSTemp);
}

static void printVal(double Val, double Total) {
  if (Total < 1e-7)   // Avoid dividing by zero...
    fprintf(stderr, "        -----     ");
  else
    fprintf(stderr, "  %7.4f (%5.1f%%)", Val, Val*100/Total);
}

void TimeRecord::print(const char *PassName, const TimeRecord &Total) const {
  printVal(UserTime, Total.UserTime);
  printVal(SystemTime, Total.SystemTime);
  printVal(UserTime+SystemTime, Total.UserTime+Total.SystemTime);
  printVal(Elapsed, Total.Elapsed);
  
  fprintf(stderr, "  ");

  if (Total.MaxRSS)
    std::cerr << MaxRSS << "\t";
  std::cerr << PassName << "\n";
}


// Create method.  If Timing is enabled, this creates and returns a new timing
// object, otherwise it returns null.
//
TimingInfo *TimingInfo::create() {
  return EnableTiming ? new TimingInfo() : 0;
}

void TimingInfo::passStarted(Pass *P) {
  TimingData[P].passStart(getTimeRecord());
}
void TimingInfo::passEnded(Pass *P) {
  TimingData[P].passEnd(getTimeRecord());
}
void TimeRecord::sum(const TimeRecord &TR) {
  Elapsed    += TR.Elapsed;
  UserTime   += TR.UserTime;
  SystemTime += TR.SystemTime;
  MaxRSS     += TR.MaxRSS;
}

// TimingDtor - Print out information about timing information
TimingInfo::~TimingInfo() {
  // Iterate over all of the data, converting it into the dual of the data map,
  // so that the data is sorted by amount of time taken, instead of pointer.
  //
  std::vector<std::pair<TimeRecord, Pass*> > Data;
  TimeRecord Total;
  for (std::map<Pass*, TimeRecord>::iterator I = TimingData.begin(),
         E = TimingData.end(); I != E; ++I)
    // Throw out results for "grouping" pass managers...
    if (!dynamic_cast<AnalysisResolver*>(I->first)) {
      Data.push_back(std::make_pair(I->second, I->first));
      Total.sum(I->second);
    }
  
  // Sort the data by time as the primary key, in reverse order...
  std::sort(Data.begin(), Data.end(),
            std::greater<std::pair<TimeRecord, Pass*> >());

  // Print out timing header...
  std::cerr << std::string(79, '=') << "\n"
            << "                      ... Pass execution timing report ...\n"
            << std::string(79, '=') << "\n  Total Execution Time: "
            << (Total.UserTime+Total.SystemTime) << " seconds ("
            << Total.Elapsed << " wall clock)\n\n   ---User Time---   "
            << "--System Time--   --User+System--   ---Wall Time---";

  if (Total.MaxRSS)
    std::cerr << " ---Mem---";
  std::cerr << "  --- Pass Name ---\n";

  // Loop through all of the timing data, printing it out...
  for (unsigned i = 0, e