Beispiel #1
0
// Check to see if this function returns one or more constants. If so, replace
// all callers that use those return values with the constant value. This will
// leave in the actual return values and instructions, but deadargelim will
// clean that up.
//
// Additionally if a function always returns one of its arguments directly,
// callers will be updated to use the value they pass in directly instead of
// using the return value.
bool IPCP::PropagateConstantReturn(Function &F) {
  if (F.getReturnType()->isVoidTy())
    return false; // No return value.

  // If this function could be overridden later in the link stage, we can't
  // propagate information about its results into callers.
  if (F.mayBeOverridden())
    return false;
    
  // Check to see if this function returns a constant.
  SmallVector<Value *,4> RetVals;
  StructType *STy = dyn_cast<StructType>(F.getReturnType());
  if (STy)
    for (unsigned i = 0, e = STy->getNumElements(); i < e; ++i) 
      RetVals.push_back(UndefValue::get(STy->getElementType(i)));
  else
    RetVals.push_back(UndefValue::get(F.getReturnType()));

  unsigned NumNonConstant = 0;
  for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
    if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) {
      for (unsigned i = 0, e = RetVals.size(); i != e; ++i) {
        // Already found conflicting return values?
        Value *RV = RetVals[i];
        if (!RV)
          continue;

        // Find the returned value
        Value *V;
        if (!STy)
          V = RI->getOperand(0);
        else
          V = FindInsertedValue(RI->getOperand(0), i);

        if (V) {
          // Ignore undefs, we can change them into anything
          if (isa<UndefValue>(V))
            continue;
          
          // Try to see if all the rets return the same constant or argument.
          if (isa<Constant>(V) || isa<Argument>(V)) {
            if (isa<UndefValue>(RV)) {
              // No value found yet? Try the current one.
              RetVals[i] = V;
              continue;
            }
            // Returning the same value? Good.
            if (RV == V)
              continue;
          }
        }
        // Different or no known return value? Don't propagate this return
        // value.
        RetVals[i] = 0;
        // All values non constant? Stop looking.
        if (++NumNonConstant == RetVals.size())
          return false;
      }
    }

  // If we got here, the function returns at least one constant value.  Loop
  // over all users, replacing any uses of the return value with the returned
  // constant.
  bool MadeChange = false;
  for (Value::use_iterator UI = F.use_begin(), E = F.use_end(); UI != E; ++UI) {
    CallSite CS(*UI);
    Instruction* Call = CS.getInstruction();

    // Not a call instruction or a call instruction that's not calling F
    // directly?
    if (!Call || !CS.isCallee(UI))
      continue;
    
    // Call result not used?
    if (Call->use_empty())
      continue;

    MadeChange = true;

    if (STy == 0) {
      Value* New = RetVals[0];
      if (Argument *A = dyn_cast<Argument>(New))
        // Was an argument returned? Then find the corresponding argument in
        // the call instruction and use that.
        New = CS.getArgument(A->getArgNo());
      Call->replaceAllUsesWith(New);
      continue;
    }
   
    for (Value::use_iterator I = Call->use_begin(), E = Call->use_end();
         I != E;) {
      Instruction *Ins = cast<Instruction>(*I);

      // Increment now, so we can remove the use
      ++I;

      // Find the index of the retval to replace with
      int index = -1;
      if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Ins))
        if (EV->hasIndices())
          index = *EV->idx_begin();

      // If this use uses a specific return value, and we have a replacement,
      // replace it.
      if (index != -1) {
        Value *New = RetVals[index];
        if (New) {
          if (Argument *A = dyn_cast<Argument>(New))
            // Was an argument returned? Then find the corresponding argument in
            // the call instruction and use that.
            New = CS.getArgument(A->getArgNo());
          Ins->replaceAllUsesWith(New);
          Ins->eraseFromParent();
        }
      }
    }
  }

  if (MadeChange) ++NumReturnValProped;
  return MadeChange;
}
Beispiel #2
0
void Diagnostic::
FormatDiagnostic(const char *DiagStr, const char *DiagEnd,
                 SmallVectorImpl<char> &OutStr) const {

  /// FormattedArgs - Keep track of all of the arguments formatted by
  /// ConvertArgToString and pass them into subsequent calls to
  /// ConvertArgToString, allowing the implementation to avoid redundancies in
  /// obvious cases.
  SmallVector<DiagnosticsEngine::ArgumentValue, 8> FormattedArgs;

  /// QualTypeVals - Pass a vector of arrays so that QualType names can be
  /// compared to see if more information is needed to be printed.
  SmallVector<intptr_t, 2> QualTypeVals;
  SmallVector<char, 64> Tree;

  for (unsigned i = 0, e = getNumArgs(); i < e; ++i)
    if (getArgKind(i) == DiagnosticsEngine::ak_qualtype)
      QualTypeVals.push_back(getRawArg(i));

  while (DiagStr != DiagEnd) {
    if (DiagStr[0] != '%') {
      // Append non-%0 substrings to Str if we have one.
      const char *StrEnd = std::find(DiagStr, DiagEnd, '%');
      OutStr.append(DiagStr, StrEnd);
      DiagStr = StrEnd;
      continue;
    } else if (ispunct(DiagStr[1])) {
      OutStr.push_back(DiagStr[1]);  // %% -> %.
      DiagStr += 2;
      continue;
    }

    // Skip the %.
    ++DiagStr;

    // This must be a placeholder for a diagnostic argument.  The format for a
    // placeholder is one of "%0", "%modifier0", or "%modifier{arguments}0".
    // The digit is a number from 0-9 indicating which argument this comes from.
    // The modifier is a string of digits from the set [-a-z]+, arguments is a
    // brace enclosed string.
    const char *Modifier = 0, *Argument = 0;
    unsigned ModifierLen = 0, ArgumentLen = 0;

    // Check to see if we have a modifier.  If so eat it.
    if (!isdigit(DiagStr[0])) {
      Modifier = DiagStr;
      while (DiagStr[0] == '-' ||
             (DiagStr[0] >= 'a' && DiagStr[0] <= 'z'))
        ++DiagStr;
      ModifierLen = DiagStr-Modifier;

      // If we have an argument, get it next.
      if (DiagStr[0] == '{') {
        ++DiagStr; // Skip {.
        Argument = DiagStr;

        DiagStr = ScanFormat(DiagStr, DiagEnd, '}');
        assert(DiagStr != DiagEnd && "Mismatched {}'s in diagnostic string!");
        ArgumentLen = DiagStr-Argument;
        ++DiagStr;  // Skip }.
      }
    }

    assert(isdigit(*DiagStr) && "Invalid format for argument in diagnostic");
    unsigned ArgNo = *DiagStr++ - '0';

    // Only used for type diffing.
    unsigned ArgNo2 = ArgNo;

    DiagnosticsEngine::ArgumentKind Kind = getArgKind(ArgNo);
    if (Kind == DiagnosticsEngine::ak_qualtype &&
        ModifierIs(Modifier, ModifierLen, "diff")) {
      Kind = DiagnosticsEngine::ak_qualtype_pair;
      assert(*DiagStr == ',' && isdigit(*(DiagStr + 1)) &&
             "Invalid format for diff modifier");
      ++DiagStr;  // Comma.
      ArgNo2 = *DiagStr++ - '0';
      assert(getArgKind(ArgNo2) == DiagnosticsEngine::ak_qualtype &&
             "Second value of type diff must be a qualtype");
    }
    
    switch (Kind) {
    // ---- STRINGS ----
    case DiagnosticsEngine::ak_std_string: {
      const std::string &S = getArgStdStr(ArgNo);
      assert(ModifierLen == 0 && "No modifiers for strings yet");
      OutStr.append(S.begin(), S.end());
      break;
    }
    case DiagnosticsEngine::ak_c_string: {
      const char *S = getArgCStr(ArgNo);
      assert(ModifierLen == 0 && "No modifiers for strings yet");

      // Don't crash if get passed a null pointer by accident.
      if (!S)
        S = "(null)";

      OutStr.append(S, S + strlen(S));
      break;
    }
    // ---- INTEGERS ----
    case DiagnosticsEngine::ak_sint: {
      int Val = getArgSInt(ArgNo);

      if (ModifierIs(Modifier, ModifierLen, "select")) {
        HandleSelectModifier(*this, (unsigned)Val, Argument, ArgumentLen,
                             OutStr);
      } else if (ModifierIs(Modifier, ModifierLen, "s")) {
        HandleIntegerSModifier(Val, OutStr);
      } else if (ModifierIs(Modifier, ModifierLen, "plural")) {
        HandlePluralModifier(*this, (unsigned)Val, Argument, ArgumentLen,
                             OutStr);
      } else if (ModifierIs(Modifier, ModifierLen, "ordinal")) {
        HandleOrdinalModifier((unsigned)Val, OutStr);
      } else {
        assert(ModifierLen == 0 && "Unknown integer modifier");
        llvm::raw_svector_ostream(OutStr) << Val;
      }
      break;
    }
    case DiagnosticsEngine::ak_uint: {
      unsigned Val = getArgUInt(ArgNo);

      if (ModifierIs(Modifier, ModifierLen, "select")) {
        HandleSelectModifier(*this, Val, Argument, ArgumentLen, OutStr);
      } else if (ModifierIs(Modifier, ModifierLen, "s")) {
        HandleIntegerSModifier(Val, OutStr);
      } else if (ModifierIs(Modifier, ModifierLen, "plural")) {
        HandlePluralModifier(*this, (unsigned)Val, Argument, ArgumentLen,
                             OutStr);
      } else if (ModifierIs(Modifier, ModifierLen, "ordinal")) {
        HandleOrdinalModifier(Val, OutStr);
      } else {
        assert(ModifierLen == 0 && "Unknown integer modifier");
        llvm::raw_svector_ostream(OutStr) << Val;
      }
      break;
    }
    // ---- NAMES and TYPES ----
    case DiagnosticsEngine::ak_identifierinfo: {
      const IdentifierInfo *II = getArgIdentifier(ArgNo);
      assert(ModifierLen == 0 && "No modifiers for strings yet");

      // Don't crash if get passed a null pointer by accident.
      if (!II) {
        const char *S = "(null)";
        OutStr.append(S, S + strlen(S));
        continue;
      }

      llvm::raw_svector_ostream(OutStr) << '\'' << II->getName() << '\'';
      break;
    }
    case DiagnosticsEngine::ak_qualtype:
    case DiagnosticsEngine::ak_declarationname:
    case DiagnosticsEngine::ak_nameddecl:
    case DiagnosticsEngine::ak_nestednamespec:
    case DiagnosticsEngine::ak_declcontext:
      getDiags()->ConvertArgToString(Kind, getRawArg(ArgNo),
                                     Modifier, ModifierLen,
                                     Argument, ArgumentLen,
                                     FormattedArgs.data(), FormattedArgs.size(),
                                     OutStr, QualTypeVals);
      break;
    case DiagnosticsEngine::ak_qualtype_pair:
      // Create a struct with all the info needed for printing.
      TemplateDiffTypes TDT;
      TDT.FromType = getRawArg(ArgNo);
      TDT.ToType = getRawArg(ArgNo2);
      TDT.ElideType = getDiags()->ElideType;
      TDT.ShowColors = getDiags()->ShowColors;
      TDT.TemplateDiffUsed = false;
      intptr_t val = reinterpret_cast<intptr_t>(&TDT);

      const char *ArgumentEnd = Argument + ArgumentLen;
      const char *Pipe = ScanFormat(Argument, ArgumentEnd, '|');

      // Print the tree.  If this diagnostic already has a tree, skip the
      // second tree.
      if (getDiags()->PrintTemplateTree && Tree.empty()) {
        TDT.PrintFromType = true;
        TDT.PrintTree = true;
        getDiags()->ConvertArgToString(Kind, val,
                                       Modifier, ModifierLen,
                                       Argument, ArgumentLen,
                                       FormattedArgs.data(),
                                       FormattedArgs.size(),
                                       Tree, QualTypeVals);
        // If there is no tree information, fall back to regular printing.
        if (!Tree.empty()) {
          FormatDiagnostic(Pipe + 1, ArgumentEnd, OutStr);
          break;
        }
      }

      // Non-tree printing, also the fall-back when tree printing fails.
      // The fall-back is triggered when the types compared are not templates.
      const char *FirstDollar = ScanFormat(Argument, ArgumentEnd, '$');
      const char *SecondDollar = ScanFormat(FirstDollar + 1, ArgumentEnd, '$');

      // Append before text
      FormatDiagnostic(Argument, FirstDollar, OutStr);

      // Append first type
      TDT.PrintTree = false;
      TDT.PrintFromType = true;
      getDiags()->ConvertArgToString(Kind, val,
                                     Modifier, ModifierLen,
                                     Argument, ArgumentLen,
                                     FormattedArgs.data(), FormattedArgs.size(),
                                     OutStr, QualTypeVals);
      if (!TDT.TemplateDiffUsed)
        FormattedArgs.push_back(std::make_pair(DiagnosticsEngine::ak_qualtype,
                                               TDT.FromType));

      // Append middle text
      FormatDiagnostic(FirstDollar + 1, SecondDollar, OutStr);

      // Append second type
      TDT.PrintFromType = false;
      getDiags()->ConvertArgToString(Kind, val,
                                     Modifier, ModifierLen,
                                     Argument, ArgumentLen,
                                     FormattedArgs.data(), FormattedArgs.size(),
                                     OutStr, QualTypeVals);
      if (!TDT.TemplateDiffUsed)
        FormattedArgs.push_back(std::make_pair(DiagnosticsEngine::ak_qualtype,
                                               TDT.ToType));

      // Append end text
      FormatDiagnostic(SecondDollar + 1, Pipe, OutStr);
      break;
    }
    
    // Remember this argument info for subsequent formatting operations.  Turn
    // std::strings into a null terminated string to make it be the same case as
    // all the other ones.
    if (Kind == DiagnosticsEngine::ak_qualtype_pair)
      continue;
    else if (Kind != DiagnosticsEngine::ak_std_string)
      FormattedArgs.push_back(std::make_pair(Kind, getRawArg(ArgNo)));
    else
      FormattedArgs.push_back(std::make_pair(DiagnosticsEngine::ak_c_string,
                                        (intptr_t)getArgStdStr(ArgNo).c_str()));
    
  }

  // Append the type tree to the end of the diagnostics.
  OutStr.append(Tree.begin(), Tree.end());
}
void
UserValue::addDefsFromCopies(LiveInterval *LI, unsigned LocNo,
                      const SmallVectorImpl<SlotIndex> &Kills,
                      SmallVectorImpl<std::pair<SlotIndex, unsigned> > &NewDefs,
                      MachineRegisterInfo &MRI, LiveIntervals &LIS) {
  if (Kills.empty())
    return;
  // Don't track copies from physregs, there are too many uses.
  if (!TargetRegisterInfo::isVirtualRegister(LI->reg))
    return;

  // Collect all the (vreg, valno) pairs that are copies of LI.
  SmallVector<std::pair<LiveInterval*, const VNInfo*>, 8> CopyValues;
  for (MachineOperand &MO : MRI.use_nodbg_operands(LI->reg)) {
    MachineInstr *MI = MO.getParent();
    // Copies of the full value.
    if (MO.getSubReg() || !MI->isCopy())
      continue;
    unsigned DstReg = MI->getOperand(0).getReg();

    // Don't follow copies to physregs. These are usually setting up call
    // arguments, and the argument registers are always call clobbered. We are
    // better off in the source register which could be a callee-saved register,
    // or it could be spilled.
    if (!TargetRegisterInfo::isVirtualRegister(DstReg))
      continue;

    // Is LocNo extended to reach this copy? If not, another def may be blocking
    // it, or we are looking at a wrong value of LI.
    SlotIndex Idx = LIS.getInstructionIndex(MI);
    LocMap::iterator I = locInts.find(Idx.getRegSlot(true));
    if (!I.valid() || I.value() != LocNo)
      continue;

    if (!LIS.hasInterval(DstReg))
      continue;
    LiveInterval *DstLI = &LIS.getInterval(DstReg);
    const VNInfo *DstVNI = DstLI->getVNInfoAt(Idx.getRegSlot());
    assert(DstVNI && DstVNI->def == Idx.getRegSlot() && "Bad copy value");
    CopyValues.push_back(std::make_pair(DstLI, DstVNI));
  }

  if (CopyValues.empty())
    return;

  DEBUG(dbgs() << "Got " << CopyValues.size() << " copies of " << *LI << '\n');

  // Try to add defs of the copied values for each kill point.
  for (unsigned i = 0, e = Kills.size(); i != e; ++i) {
    SlotIndex Idx = Kills[i];
    for (unsigned j = 0, e = CopyValues.size(); j != e; ++j) {
      LiveInterval *DstLI = CopyValues[j].first;
      const VNInfo *DstVNI = CopyValues[j].second;
      if (DstLI->getVNInfoAt(Idx) != DstVNI)
        continue;
      // Check that there isn't already a def at Idx
      LocMap::iterator I = locInts.find(Idx);
      if (I.valid() && I.start() <= Idx)
        continue;
      DEBUG(dbgs() << "Kill at " << Idx << " covered by valno #"
                   << DstVNI->id << " in " << *DstLI << '\n');
      MachineInstr *CopyMI = LIS.getInstructionFromIndex(DstVNI->def);
      assert(CopyMI && CopyMI->isCopy() && "Bad copy value");
      unsigned LocNo = getLocationNo(CopyMI->getOperand(0));
      I.insert(Idx, Idx.getNextSlot(), LocNo);
      NewDefs.push_back(std::make_pair(Idx, LocNo));
      break;
    }
  }
}
Beispiel #4
0
/// Compute the actions table and gather the first action index for each landing
/// pad site.
unsigned EHStreamer::
computeActionsTable(const SmallVectorImpl<const LandingPadInfo*> &LandingPads,
                    SmallVectorImpl<ActionEntry> &Actions,
                    SmallVectorImpl<unsigned> &FirstActions) {

  // The action table follows the call-site table in the LSDA. The individual
  // records are of two types:
  //
  //   * Catch clause
  //   * Exception specification
  //
  // The two record kinds have the same format, with only small differences.
  // They are distinguished by the "switch value" field: Catch clauses
  // (TypeInfos) have strictly positive switch values, and exception
  // specifications (FilterIds) have strictly negative switch values. Value 0
  // indicates a catch-all clause.
  //
  // Negative type IDs index into FilterIds. Positive type IDs index into
  // TypeInfos.  The value written for a positive type ID is just the type ID
  // itself.  For a negative type ID, however, the value written is the
  // (negative) byte offset of the corresponding FilterIds entry.  The byte
  // offset is usually equal to the type ID (because the FilterIds entries are
  // written using a variable width encoding, which outputs one byte per entry
  // as long as the value written is not too large) but can differ.  This kind
  // of complication does not occur for positive type IDs because type infos are
  // output using a fixed width encoding.  FilterOffsets[i] holds the byte
  // offset corresponding to FilterIds[i].

  const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
  SmallVector<int, 16> FilterOffsets;
  FilterOffsets.reserve(FilterIds.size());
  int Offset = -1;

  for (std::vector<unsigned>::const_iterator
         I = FilterIds.begin(), E = FilterIds.end(); I != E; ++I) {
    FilterOffsets.push_back(Offset);
    Offset -= getULEB128Size(*I);
  }

  FirstActions.reserve(LandingPads.size());

  int FirstAction = 0;
  unsigned SizeActions = 0;
  const LandingPadInfo *PrevLPI = nullptr;

  for (SmallVectorImpl<const LandingPadInfo *>::const_iterator
         I = LandingPads.begin(), E = LandingPads.end(); I != E; ++I) {
    const LandingPadInfo *LPI = *I;
    const std::vector<int> &TypeIds = LPI->TypeIds;
    unsigned NumShared = PrevLPI ? sharedTypeIDs(LPI, PrevLPI) : 0;
    unsigned SizeSiteActions = 0;

    if (NumShared < TypeIds.size()) {
      unsigned SizeAction = 0;
      unsigned PrevAction = (unsigned)-1;

      if (NumShared) {
        unsigned SizePrevIds = PrevLPI->TypeIds.size();
        assert(Actions.size());
        PrevAction = Actions.size() - 1;
        SizeAction = getSLEB128Size(Actions[PrevAction].NextAction) +
                     getSLEB128Size(Actions[PrevAction].ValueForTypeID);

        for (unsigned j = NumShared; j != SizePrevIds; ++j) {
          assert(PrevAction != (unsigned)-1 && "PrevAction is invalid!");
          SizeAction -= getSLEB128Size(Actions[PrevAction].ValueForTypeID);
          SizeAction += -Actions[PrevAction].NextAction;
          PrevAction = Actions[PrevAction].Previous;
        }
      }

      // Compute the actions.
      for (unsigned J = NumShared, M = TypeIds.size(); J != M; ++J) {
        int TypeID = TypeIds[J];
        assert(-1 - TypeID < (int)FilterOffsets.size() && "Unknown filter id!");
        int ValueForTypeID = TypeID < 0 ? FilterOffsets[-1 - TypeID] : TypeID;
        unsigned SizeTypeID = getSLEB128Size(ValueForTypeID);

        int NextAction = SizeAction ? -(SizeAction + SizeTypeID) : 0;
        SizeAction = SizeTypeID + getSLEB128Size(NextAction);
        SizeSiteActions += SizeAction;

        ActionEntry Action = { ValueForTypeID, NextAction, PrevAction };
        Actions.push_back(Action);
        PrevAction = Actions.size() - 1;
      }

      // Record the first action of the landing pad site.
      FirstAction = SizeActions + SizeSiteActions - SizeAction + 1;
    } // else identical - re-use previous FirstAction

    // Information used when created the call-site table. The action record
    // field of the call site record is the offset of the first associated
    // action record, relative to the start of the actions table. This value is
    // biased by 1 (1 indicating the start of the actions table), and 0
    // indicates that there are no actions.
    FirstActions.push_back(FirstAction);

    // Compute this sites contribution to size.
    SizeActions += SizeSiteActions;

    PrevLPI = LPI;
  }

  return SizeActions;
}
Beispiel #5
0
/// ClusterNeighboringLoads - Force nearby loads together by "gluing" them.
/// This function finds loads of the same base and different offsets. If the
/// offsets are not far apart (target specific), it add MVT::Glue inputs and
/// outputs to ensure they are scheduled together and in order. This
/// optimization may benefit some targets by improving cache locality.
void ScheduleDAGSDNodes::ClusterNeighboringLoads(SDNode *Node) {
  SDNode *Chain = nullptr;
  unsigned NumOps = Node->getNumOperands();
  if (Node->getOperand(NumOps-1).getValueType() == MVT::Other)
    Chain = Node->getOperand(NumOps-1).getNode();
  if (!Chain)
    return;

  // Look for other loads of the same chain. Find loads that are loading from
  // the same base pointer and different offsets.
  SmallPtrSet<SDNode*, 16> Visited;
  SmallVector<int64_t, 4> Offsets;
  DenseMap<long long, SDNode*> O2SMap;  // Map from offset to SDNode.
  bool Cluster = false;
  SDNode *Base = Node;
  // This algorithm requires a reasonably low use count before finding a match
  // to avoid uselessly blowing up compile time in large blocks.
  unsigned UseCount = 0;
  for (SDNode::use_iterator I = Chain->use_begin(), E = Chain->use_end();
       I != E && UseCount < 100; ++I, ++UseCount) {
    SDNode *User = *I;
    if (User == Node || !Visited.insert(User).second)
      continue;
    int64_t Offset1, Offset2;
    if (!TII->areLoadsFromSameBasePtr(Base, User, Offset1, Offset2) ||
        Offset1 == Offset2)
      // FIXME: Should be ok if they addresses are identical. But earlier
      // optimizations really should have eliminated one of the loads.
      continue;
    if (O2SMap.insert(std::make_pair(Offset1, Base)).second)
      Offsets.push_back(Offset1);
    O2SMap.insert(std::make_pair(Offset2, User));
    Offsets.push_back(Offset2);
    if (Offset2 < Offset1)
      Base = User;
    Cluster = true;
    // Reset UseCount to allow more matches.
    UseCount = 0;
  }

  if (!Cluster)
    return;

  // Sort them in increasing order.
  std::sort(Offsets.begin(), Offsets.end());

  // Check if the loads are close enough.
  SmallVector<SDNode*, 4> Loads;
  unsigned NumLoads = 0;
  int64_t BaseOff = Offsets[0];
  SDNode *BaseLoad = O2SMap[BaseOff];
  Loads.push_back(BaseLoad);
  for (unsigned i = 1, e = Offsets.size(); i != e; ++i) {
    int64_t Offset = Offsets[i];
    SDNode *Load = O2SMap[Offset];
    if (!TII->shouldScheduleLoadsNear(BaseLoad, Load, BaseOff, Offset,NumLoads))
      break; // Stop right here. Ignore loads that are further away.
    Loads.push_back(Load);
    ++NumLoads;
  }

  if (NumLoads == 0)
    return;

  // Cluster loads by adding MVT::Glue outputs and inputs. This also
  // ensure they are scheduled in order of increasing addresses.
  SDNode *Lead = Loads[0];
  SDValue InGlue = SDValue(nullptr, 0);
  if (AddGlue(Lead, InGlue, true, DAG))
    InGlue = SDValue(Lead, Lead->getNumValues() - 1);
  for (unsigned I = 1, E = Loads.size(); I != E; ++I) {
    bool OutGlue = I < E - 1;
    SDNode *Load = Loads[I];

    // If AddGlue fails, we could leave an unsused glue value. This should not
    // cause any
    if (AddGlue(Load, InGlue, OutGlue, DAG)) {
      if (OutGlue)
        InGlue = SDValue(Load, Load->getNumValues() - 1);

      ++LoadsClustered;
    }
    else if (!OutGlue && InGlue.getNode())
      RemoveUnusedGlue(InGlue.getNode(), DAG);
  }
}
Beispiel #6
0
/// Emit a checked cast to a protocol or protocol composition.
void irgen::emitScalarExistentialDowncast(IRGenFunction &IGF,
                                  llvm::Value *value,
                                  SILType srcType,
                                  SILType destType,
                                  CheckedCastMode mode,
                                  Optional<MetatypeRepresentation> metatypeKind,
                                  Explosion &ex) {
  SmallVector<ProtocolDecl*, 4> allProtos;
  destType.getSwiftRValueType().getAnyExistentialTypeProtocols(allProtos);

  // Look up witness tables for the protocols that need them and get
  // references to the ObjC Protocol* values for the objc protocols.
  SmallVector<llvm::Value*, 4> objcProtos;
  SmallVector<llvm::Value*, 4> witnessTableProtos;

  bool hasClassConstraint = false;
  bool hasClassConstraintByProtocol = false;

  for (auto proto : allProtos) {
    // If the protocol introduces a class constraint, track whether we need
    // to check for it independent of protocol witnesses.
    if (proto->requiresClass()) {
      hasClassConstraint = true;
      if (proto->getKnownProtocolKind()
          && *proto->getKnownProtocolKind() == KnownProtocolKind::AnyObject) {
        // AnyObject only requires that the type be a class.
        continue;
      }
      
      // If this protocol is class-constrained but not AnyObject, checking its
      // conformance will check the class constraint too.
      hasClassConstraintByProtocol = true;
    }

    if (Lowering::TypeConverter::protocolRequiresWitnessTable(proto)) {
      auto descriptor = emitProtocolDescriptorRef(IGF, proto);
      witnessTableProtos.push_back(descriptor);
    }

    if (!proto->isObjC())
      continue;

    objcProtos.push_back(emitReferenceToObjCProtocol(IGF, proto));
  }
  
  llvm::Type *resultType;
  if (metatypeKind) {
    switch (*metatypeKind) {
    case MetatypeRepresentation::Thin:
      llvm_unreachable("can't cast to thin metatype");
    case MetatypeRepresentation::Thick:
      resultType = IGF.IGM.TypeMetadataPtrTy;
      break;
    case MetatypeRepresentation::ObjC:
      resultType = IGF.IGM.ObjCClassPtrTy;
      break;
    }
  } else {
    auto schema = IGF.getTypeInfo(destType).getSchema();
    resultType = schema[0].getScalarType();
  }
  // We only need to check the class constraint for metatype casts where
  // no protocol conformance indirectly requires the constraint for us.
  bool checkClassConstraint =
    (bool)metatypeKind && hasClassConstraint && !hasClassConstraintByProtocol;

  llvm::Value *resultValue = value;

  // If we don't have anything we really need to check, then trivially succeed.
  if (objcProtos.empty() && witnessTableProtos.empty() &&
      !checkClassConstraint) {
    resultValue = IGF.Builder.CreateBitCast(value, resultType);
    ex.add(resultValue);
    return;
  }

  // Check the ObjC protocol conformances if there were any.
  llvm::Value *objcCast = nullptr;
  if (!objcProtos.empty()) {
    // Get the ObjC instance or class object to check for these conformances.
    llvm::Value *objcObject;
    if (metatypeKind) {
      switch (*metatypeKind) {
      case MetatypeRepresentation::Thin:
        llvm_unreachable("can't cast to thin metatype");
      case MetatypeRepresentation::Thick: {
        // The metadata might be for a non-class type, which wouldn't have
        // an ObjC class object.
        objcObject = nullptr;
        break;
      }
      case MetatypeRepresentation::ObjC:
        // Metatype is already an ObjC object.
        objcObject = value;
        break;
      }
    } else {
      // Class instance is already an ObjC object.
      objcObject = value;
    }
    if (objcObject)
      objcObject = IGF.Builder.CreateBitCast(objcObject,
                                             IGF.IGM.UnknownRefCountedPtrTy);
    
    // Pick the cast function based on the cast mode and on whether we're
    // casting a Swift metatype or ObjC object.
    llvm::Value *castFn;
    switch (mode) {
    case CheckedCastMode::Unconditional:
      castFn = objcObject
        ? IGF.IGM.getDynamicCastObjCProtocolUnconditionalFn()
        : IGF.IGM.getDynamicCastTypeToObjCProtocolUnconditionalFn();
      break;
    case CheckedCastMode::Conditional:
      castFn = objcObject
        ? IGF.IGM.getDynamicCastObjCProtocolConditionalFn()
        : IGF.IGM.getDynamicCastTypeToObjCProtocolConditionalFn();
      break;
    }
    llvm::Value *objcCastObject = objcObject ? objcObject : value;
    
    Address protoRefsBuf = IGF.createAlloca(
                                        llvm::ArrayType::get(IGF.IGM.Int8PtrTy,
                                                             objcProtos.size()),
                                        IGF.IGM.getPointerAlignment(),
                                        "objc_protocols");
    protoRefsBuf = IGF.Builder.CreateBitCast(protoRefsBuf,
                                             IGF.IGM.Int8PtrPtrTy);

    for (unsigned index : indices(objcProtos)) {
      Address protoRefSlot = IGF.Builder.CreateConstArrayGEP(
                                                     protoRefsBuf, index,
                                                     IGF.IGM.getPointerSize());
      IGF.Builder.CreateStore(objcProtos[index], protoRefSlot);
      ++index;
    }

    
    auto cc = IGF.IGM.DefaultCC;
    if (auto fun = dyn_cast<llvm::Function>(castFn))
      cc = fun->getCallingConv();


    auto call = IGF.Builder.CreateCall(
        castFn,
        {objcCastObject, IGF.IGM.getSize(Size(objcProtos.size())),
         protoRefsBuf.getAddress()});
    call->setCallingConv(cc);
    objcCast = call;
    resultValue = IGF.Builder.CreateBitCast(objcCast, resultType);
  }

  // If we don't need to look up any witness tables, we're done.
  if (witnessTableProtos.empty() && !checkClassConstraint) {
    ex.add(resultValue);
    return;
  }

  // If we're doing a conditional cast, and the ObjC protocol checks failed,
  // then the cast is done.
  Optional<ConditionalDominanceScope> condition;
  llvm::BasicBlock *origBB = nullptr, *successBB = nullptr, *contBB = nullptr;
  if (!objcProtos.empty()) {
    switch (mode) {
    case CheckedCastMode::Unconditional:
      break;
    case CheckedCastMode::Conditional: {
      origBB = IGF.Builder.GetInsertBlock();
      successBB = IGF.createBasicBlock("success");
      contBB = IGF.createBasicBlock("cont");
      auto isNull = IGF.Builder.CreateICmpEQ(objcCast,
                               llvm::ConstantPointerNull::get(
                                 cast<llvm::PointerType>(objcCast->getType())));
      IGF.Builder.CreateCondBr(isNull, contBB, successBB);
      IGF.Builder.emitBlock(successBB);
      condition.emplace(IGF);
    }
    }
  }

  // Get the Swift type metadata for the type.
  llvm::Value *metadataValue;
  if (metatypeKind) {
    switch (*metatypeKind) {
    case MetatypeRepresentation::Thin:
      llvm_unreachable("can't cast to thin metatype");
    case MetatypeRepresentation::Thick:
      // The value is already a native metatype.
      metadataValue = value;
      break;
    case MetatypeRepresentation::ObjC:
      // Get the type metadata from the ObjC class, which may be a wrapper.
      metadataValue = emitObjCMetadataRefForMetadata(IGF, value);
    }
  } else {
    // Get the type metadata for the instance.
    metadataValue = emitDynamicTypeOfHeapObject(IGF, value, srcType);
  }

  // Look up witness tables for the protocols that need them.
  auto fn = emitExistentialScalarCastFn(IGF.IGM, witnessTableProtos.size(),
                                        mode, checkClassConstraint);

  llvm::SmallVector<llvm::Value *, 4> args;

  if (resultValue->getType() != IGF.IGM.Int8PtrTy)
    resultValue = IGF.Builder.CreateBitCast(resultValue, IGF.IGM.Int8PtrTy);
  args.push_back(resultValue);

  args.push_back(metadataValue);
  for (auto proto : witnessTableProtos)
    args.push_back(proto);

  auto valueAndWitnessTables = IGF.Builder.CreateCall(fn, args);

  resultValue = IGF.Builder.CreateExtractValue(valueAndWitnessTables, 0);
  if (resultValue->getType() != resultType)
    resultValue = IGF.Builder.CreateBitCast(resultValue, resultType);
  ex.add(resultValue);

  for (unsigned i = 0, e = witnessTableProtos.size(); i < e; ++i) {
    auto wt = IGF.Builder.CreateExtractValue(valueAndWitnessTables, i + 1);
    ex.add(wt);
  }

  // If we had conditional ObjC checks, join the failure paths.
  if (contBB) {
    condition.reset();
    IGF.Builder.CreateBr(contBB);
    IGF.Builder.emitBlock(contBB);
    
    // Return null on the failure path.
    Explosion successEx = std::move(ex);
    ex.reset();
    
    while (!successEx.empty()) {
      auto successVal = successEx.claimNext();
      auto failureVal = llvm::Constant::getNullValue(successVal->getType());
      auto phi = IGF.Builder.CreatePHI(successVal->getType(), 2);
      phi->addIncoming(successVal, successBB);
      phi->addIncoming(failureVal, origBB);
      ex.add(phi);
    }
  }
}
Beispiel #7
0
/// ParseBlock - Read a block, updating statistics, etc.
static bool ParseBlock(BitstreamCursor &Stream, unsigned IndentLevel) {
  std::string Indent(IndentLevel*2, ' ');
  uint64_t BlockBitStart = Stream.GetCurrentBitNo();
  unsigned BlockID = Stream.ReadSubBlockID();

  // Get the statistics for this BlockID.
  PerBlockIDStats &BlockStats = BlockIDStats[BlockID];

  BlockStats.NumInstances++;

  // BLOCKINFO is a special part of the stream.
  if (BlockID == bitc::BLOCKINFO_BLOCK_ID) {
    if (Dump) errs() << Indent << "<BLOCKINFO_BLOCK/>\n";
    if (Stream.ReadBlockInfoBlock())
      return Error("Malformed BlockInfoBlock");
    uint64_t BlockBitEnd = Stream.GetCurrentBitNo();
    BlockStats.NumBits += BlockBitEnd-BlockBitStart;
    return false;
  }

  unsigned NumWords = 0;
  if (Stream.EnterSubBlock(BlockID, &NumWords))
    return Error("Malformed block record");

  const char *BlockName = 0;
  if (Dump) {
    errs() << Indent << "<";
    if ((BlockName = GetBlockName(BlockID, *Stream.getBitStreamReader())))
      errs() << BlockName;
    else
      errs() << "UnknownBlock" << BlockID;

    if (NonSymbolic && BlockName)
      errs() << " BlockID=" << BlockID;

    errs() << " NumWords=" << NumWords
           << " BlockCodeSize=" << Stream.GetAbbrevIDWidth() << ">\n";
  }

  SmallVector<uint64_t, 64> Record;

  // Read all the records for this block.
  while (1) {
    if (Stream.AtEndOfStream())
      return Error("Premature end of bitstream");

    uint64_t RecordStartBit = Stream.GetCurrentBitNo();

    // Read the code for this record.
    unsigned AbbrevID = Stream.ReadCode();
    switch (AbbrevID) {
    case bitc::END_BLOCK: {
      if (Stream.ReadBlockEnd())
        return Error("Error at end of block");
      uint64_t BlockBitEnd = Stream.GetCurrentBitNo();
      BlockStats.NumBits += BlockBitEnd-BlockBitStart;
      if (Dump) {
        errs() << Indent << "</";
        if (BlockName)
          errs() << BlockName << ">\n";
        else
          errs() << "UnknownBlock" << BlockID << ">\n";
      }
      return false;
    }
    case bitc::ENTER_SUBBLOCK: {
      uint64_t SubBlockBitStart = Stream.GetCurrentBitNo();
      if (ParseBlock(Stream, IndentLevel+1))
        return true;
      ++BlockStats.NumSubBlocks;
      uint64_t SubBlockBitEnd = Stream.GetCurrentBitNo();

      // Don't include subblock sizes in the size of this block.
      BlockBitStart += SubBlockBitEnd-SubBlockBitStart;
      break;
    }
    case bitc::DEFINE_ABBREV:
      Stream.ReadAbbrevRecord();
      ++BlockStats.NumAbbrevs;
      break;
    default:
      Record.clear();

      ++BlockStats.NumRecords;
      if (AbbrevID != bitc::UNABBREV_RECORD)
        ++BlockStats.NumAbbreviatedRecords;

      const char *BlobStart = 0;
      unsigned BlobLen = 0;
      unsigned Code = Stream.ReadRecord(AbbrevID, Record, BlobStart, BlobLen);



      // Increment the # occurrences of this code.
      if (BlockStats.CodeFreq.size() <= Code)
        BlockStats.CodeFreq.resize(Code+1);
      BlockStats.CodeFreq[Code].NumInstances++;
      BlockStats.CodeFreq[Code].TotalBits +=
        Stream.GetCurrentBitNo()-RecordStartBit;
      if (AbbrevID != bitc::UNABBREV_RECORD)
        BlockStats.CodeFreq[Code].NumAbbrev++;

      if (Dump) {
        errs() << Indent << "  <";
        if (const char *CodeName =
              GetCodeName(Code, BlockID, *Stream.getBitStreamReader()))
          errs() << CodeName;
        else
          errs() << "UnknownCode" << Code;
        if (NonSymbolic &&
            GetCodeName(Code, BlockID, *Stream.getBitStreamReader()))
          errs() << " codeid=" << Code;
        if (AbbrevID != bitc::UNABBREV_RECORD)
          errs() << " abbrevid=" << AbbrevID;

        for (unsigned i = 0, e = Record.size(); i != e; ++i)
          errs() << " op" << i << "=" << (int64_t)Record[i];

        errs() << "/>";

        if (BlobStart) {
          errs() << " blob data = ";
          bool BlobIsPrintable = true;
          for (unsigned i = 0; i != BlobLen; ++i)
            if (!isprint(BlobStart[i])) {
              BlobIsPrintable = false;
              break;
            }

          if (BlobIsPrintable)
            errs() << "'" << std::string(BlobStart, BlobStart+BlobLen) <<"'";
          else
            errs() << "unprintable, " << BlobLen << " bytes.";
        }

        errs() << "\n";
      }

      break;
    }
  }
}
Beispiel #8
0
void ValueEnumerator::incorporateFunction(const Function &F) {
  InstructionCount = 0;
  NumModuleValues = Values.size();
  NumModuleMDValues = MDValues.size();

  // Adding function arguments to the value table.
  for (Function::const_arg_iterator I = F.arg_begin(), E = F.arg_end();
       I != E; ++I)
    EnumerateValue(I);

  FirstFuncConstantID = Values.size();

  // Add all function-level constants to the value table.
  for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I!=E; ++I)
      for (User::const_op_iterator OI = I->op_begin(), E = I->op_end();
           OI != E; ++OI) {
        if ((isa<Constant>(*OI) && !isa<GlobalValue>(*OI)) ||
            isa<InlineAsm>(*OI))
          EnumerateValue(*OI);
      }
    BasicBlocks.push_back(BB);
    ValueMap[BB] = BasicBlocks.size();
  }

  // Optimize the constant layout.
  OptimizeConstants(FirstFuncConstantID, Values.size());

  // Add the function's parameter attributes so they are available for use in
  // the function's instruction.
  EnumerateAttributes(F.getAttributes());

  FirstInstID = Values.size();

  SmallVector<MDNode *, 8> FnLocalMDVector;
  // Add all of the instructions.
  for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I!=E; ++I) {
      for (User::const_op_iterator OI = I->op_begin(), E = I->op_end();
           OI != E; ++OI) {
        if (MDNode *MD = dyn_cast<MDNode>(*OI))
          if (MD->isFunctionLocal() && MD->getFunction())
            // Enumerate metadata after the instructions they might refer to.
            FnLocalMDVector.push_back(MD);
      }

      SmallVector<std::pair<unsigned, MDNode*>, 8> MDs;
      I->getAllMetadataOtherThanDebugLoc(MDs);
      for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
        MDNode *N = MDs[i].second;
        if (N->isFunctionLocal() && N->getFunction())
          FnLocalMDVector.push_back(N);
      }
        
      if (!I->getType()->isVoidTy())
        EnumerateValue(I);
    }
  }

  // Add all of the function-local metadata.
  for (unsigned i = 0, e = FnLocalMDVector.size(); i != e; ++i)
    EnumerateFunctionLocalMetadata(FnLocalMDVector[i]);
}
// recurseBasicBlock() - This calculates the ProfileInfo estimation for a
// single block and then recurses into the successors.
// The algorithm preserves the flow condition, meaning that the sum of the
// weight of the incoming edges must be equal the block weight which must in
// turn be equal to the sume of the weights of the outgoing edges.
// Since the flow of an block is deterimined from the current state of the
// flow, once an edge has a flow assigned this flow is never changed again,
// otherwise it would be possible to violate the flow condition in another
// block.
void ProfileEstimatorPass::recurseBasicBlock(BasicBlock *BB) {

  // Break the recursion if this BasicBlock was already visited.
  if (BBToVisit.find(BB) == BBToVisit.end()) return;

  // Read the LoopInfo for this block.
  bool  BBisHeader = LI->isLoopHeader(BB);
  Loop* BBLoop     = LI->getLoopFor(BB);

  // To get the block weight, read all incoming edges.
  double BBWeight = 0;
  std::set<BasicBlock*> ProcessedPreds;
  for ( pred_iterator bbi = pred_begin(BB), bbe = pred_end(BB);
        bbi != bbe; ++bbi ) {
    // If this block was not considered already, add weight.
    Edge edge = getEdge(*bbi,BB);
    double w = getEdgeWeight(edge);
    if (ProcessedPreds.insert(*bbi).second) {
      BBWeight += ignoreMissing(w);
    }
    // If this block is a loop header and the predecessor is contained in this
    // loop, thus the edge is a backedge, continue and do not check if the
    // value is valid.
    if (BBisHeader && BBLoop->contains(*bbi)) {
      printEdgeError(edge, "but is backedge, continuing");
      continue;
    }
    // If the edges value is missing (and this is no loop header, and this is
    // no backedge) return, this block is currently non estimatable.
    if (w == MissingValue) {
      printEdgeError(edge, "returning");
      return;
    }
  }
  if (getExecutionCount(BB) != MissingValue) {
    BBWeight = getExecutionCount(BB);
  }

  // Fetch all necessary information for current block.
  SmallVector<Edge, 8> ExitEdges;
  SmallVector<Edge, 8> Edges;
  if (BBLoop) {
    BBLoop->getExitEdges(ExitEdges);
  }

  // If this is a loop header, consider the following:
  // Exactly the flow that is entering this block, must exit this block too. So
  // do the following: 
  // *) get all the exit edges, read the flow that is already leaving this
  // loop, remember the edges that do not have any flow on them right now.
  // (The edges that have already flow on them are most likely exiting edges of
  // other loops, do not touch those flows because the previously caclulated
  // loopheaders would not be exact anymore.)
  // *) In case there is not a single exiting edge left, create one at the loop
  // latch to prevent the flow from building up in the loop.
  // *) Take the flow that is not leaving the loop already and distribute it on
  // the remaining exiting edges.
  // (This ensures that all flow that enters the loop also leaves it.)
  // *) Increase the flow into the loop by increasing the weight of this block.
  // There is at least one incoming backedge that will bring us this flow later
  // on. (So that the flow condition in this node is valid again.)
  if (BBisHeader) {
    double incoming = BBWeight;
    // Subtract the flow leaving the loop.
    std::set<Edge> ProcessedExits;
    for (SmallVector<Edge, 8>::iterator ei = ExitEdges.begin(),
         ee = ExitEdges.end(); ei != ee; ++ei) {
      if (ProcessedExits.insert(*ei).second) {
        double w = getEdgeWeight(*ei);
        if (w == MissingValue) {
          Edges.push_back(*ei);
          // Check if there is a necessary minimal weight, if yes, subtract it 
          // from weight.
          if (MinimalWeight.find(*ei) != MinimalWeight.end()) {
            incoming -= MinimalWeight[*ei];
            DEBUG(dbgs() << "Reserving " << format("%.20g",MinimalWeight[*ei]) << " at " << (*ei) << "\n");
          }
        } else {
          incoming -= w;
        }
      }
    }
    // If no exit edges, create one:
    if (Edges.size() == 0) {
      BasicBlock *Latch = BBLoop->getLoopLatch();
      if (Latch) {
        Edge edge = getEdge(Latch,0);
        EdgeInformation[BB->getParent()][edge] = BBWeight;
        printEdgeWeight(edge);
        edge = getEdge(Latch, BB);
        EdgeInformation[BB->getParent()][edge] = BBWeight * ExecCount;
        printEdgeWeight(edge);
      }
    }

    // Distribute remaining weight to the exting edges. To prevent fractions
    // from building up and provoking precision problems the weight which is to
    // be distributed is split and the rounded, the last edge gets a somewhat
    // bigger value, but we are close enough for an estimation.
    double fraction = floor(incoming/Edges.size());
    for (SmallVector<Edge, 8>::iterator ei = Edges.begin(), ee = Edges.end();
         ei != ee; ++ei) {
      double w = 0;
      if (ei != (ee-1)) {
        w = fraction;
        incoming -= fraction;
      } else {
        w = incoming;
      }
      EdgeInformation[BB->getParent()][*ei] += w;
      // Read necessary minimal weight.
      if (MinimalWeight.find(*ei) != MinimalWeight.end()) {
        EdgeInformation[BB->getParent()][*ei] += MinimalWeight[*ei];
        DEBUG(dbgs() << "Additionally " << format("%.20g",MinimalWeight[*ei]) << " at " << (*ei) << "\n");
      }
      printEdgeWeight(*ei);
      
      // Add minimal weight to paths to all exit edges, this is used to ensure
      // that enough flow is reaching this edges.
      Path p;
      const BasicBlock *Dest = GetPath(BB, (*ei).first, p, GetPathToDest);
      while (Dest != BB) {
        const BasicBlock *Parent = p.find(Dest)->second;
        Edge e = getEdge(Parent, Dest);
        if (MinimalWeight.find(e) == MinimalWeight.end()) {
          MinimalWeight[e] = 0;
        }
        MinimalWeight[e] += w;
        DEBUG(dbgs() << "Minimal Weight for " << e << ": " << format("%.20g",MinimalWeight[e]) << "\n");
        Dest = Parent;
      }
    }
    // Increase flow into the loop.
    BBWeight *= (ExecCount+1);
  }

  BlockInformation[BB->getParent()][BB] = BBWeight;
  // Up until now we considered only the loop exiting edges, now we have a
  // definite block weight and must distribute this onto the outgoing edges.
  // Since there may be already flow attached to some of the edges, read this
  // flow first and remember the edges that have still now flow attached.
  Edges.clear();
  std::set<BasicBlock*> ProcessedSuccs;

  succ_iterator bbi = succ_begin(BB), bbe = succ_end(BB);
  // Also check for (BB,0) edges that may already contain some flow. (But only
  // in case there are no successors.)
  if (bbi == bbe) {
    Edge edge = getEdge(BB,0);
    EdgeInformation[BB->getParent()][edge] = BBWeight;
    printEdgeWeight(edge);
  }
  for ( ; bbi != bbe; ++bbi ) {
    if (ProcessedSuccs.insert(*bbi).second) {
      Edge edge = getEdge(BB,*bbi);
      double w = getEdgeWeight(edge);
      if (w != MissingValue) {
        BBWeight -= getEdgeWeight(edge);
      } else {
        Edges.push_back(edge);
        // If minimal weight is necessary, reserve weight by subtracting weight
        // from block weight, this is readded later on.
        if (MinimalWeight.find(edge) != MinimalWeight.end()) {
          BBWeight -= MinimalWeight[edge];
          DEBUG(dbgs() << "Reserving " << format("%.20g",MinimalWeight[edge]) << " at " << edge << "\n");
        }
      }
    }
  }

  double fraction = floor(BBWeight/Edges.size());
  // Finally we know what flow is still not leaving the block, distribute this
  // flow onto the empty edges.
  for (SmallVector<Edge, 8>::iterator ei = Edges.begin(), ee = Edges.end();
       ei != ee; ++ei) {
    if (ei != (ee-1)) {
      EdgeInformation[BB->getParent()][*ei] += fraction;
      BBWeight -= fraction;
    } else {
      EdgeInformation[BB->getParent()][*ei] += BBWeight;
    }
    // Readd minial necessary weight.
    if (MinimalWeight.find(*ei) != MinimalWeight.end()) {
      EdgeInformation[BB->getParent()][*ei] += MinimalWeight[*ei];
      DEBUG(dbgs() << "Additionally " << format("%.20g",MinimalWeight[*ei]) << " at " << (*ei) << "\n");
    }
    printEdgeWeight(*ei);
  }

  // This block is visited, mark this before the recursion.
  BBToVisit.erase(BB);

  // Recurse into successors.
  for (succ_iterator bbi = succ_begin(BB), bbe = succ_end(BB);
       bbi != bbe; ++bbi) {
    recurseBasicBlock(*bbi);
  }
}
Beispiel #10
0
/// LowerFormalArguments - transform physical registers into virtual registers
/// and generate load operations for arguments places on the stack.
SDValue
Cpu0TargetLowering::LowerFormalArguments(SDValue Chain,
                                         CallingConv::ID CallConv,
                                         bool isVarArg,
                                      const SmallVectorImpl<ISD::InputArg> &Ins,
                                         DebugLoc dl, SelectionDAG &DAG,
                                         SmallVectorImpl<SDValue> &InVals)
                                          const {
  MachineFunction &MF = DAG.getMachineFunction();
  MachineFrameInfo *MFI = MF.getFrameInfo();
  Cpu0FunctionInfo *Cpu0FI = MF.getInfo<Cpu0FunctionInfo>();

  Cpu0FI->setVarArgsFrameIndex(0);

  // Used with vargs to acumulate store chains.
  std::vector<SDValue> OutChains;

  // Assign locations to all of the incoming arguments.
  SmallVector<CCValAssign, 16> ArgLocs;
  CCState CCInfo(CallConv, isVarArg, DAG.getMachineFunction(),
                 getTargetMachine(), ArgLocs, *DAG.getContext());
                         
  CCInfo.AnalyzeFormalArguments(Ins, CC_Cpu0);

  Function::const_arg_iterator FuncArg =
    DAG.getMachineFunction().getFunction()->arg_begin();
  int LastFI = 0;// Cpu0FI->LastInArgFI is 0 at the entry of this function.

  for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i, ++FuncArg) {
    CCValAssign &VA = ArgLocs[i];
    EVT ValVT = VA.getValVT();
    ISD::ArgFlagsTy Flags = Ins[i].Flags;
    bool IsRegLoc = VA.isRegLoc();

    if (Flags.isByVal()) {
      assert(Flags.getByValSize() &&
             "ByVal args of size 0 should have been ignored by front-end."); 
      continue;
    }
    // sanity check
    assert(VA.isMemLoc());

    // The stack pointer offset is relative to the caller stack frame.
    LastFI = MFI->CreateFixedObject(ValVT.getSizeInBits()/8,
                                    VA.getLocMemOffset(), true);

    // Create load nodes to retrieve arguments from the stack
    SDValue FIN = DAG.getFrameIndex(LastFI, getPointerTy());
    InVals.push_back(DAG.getLoad(ValVT, dl, Chain, FIN,
                                 MachinePointerInfo::getFixedStack(LastFI),
                                 false, false, false, 0));
  }
  Cpu0FI->setLastInArgFI(LastFI);
  // All stores are grouped in one node to allow the matching between
  // the size of Ins and InVals. This only happens when on varg functions
  if (!OutChains.empty()) {
    OutChains.push_back(Chain);
    Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other,
                        &OutChains[0], OutChains.size());
  }
  return Chain;
}
Beispiel #11
0
/// ValueEnumerator - Enumerate module-level information.
ValueEnumerator::ValueEnumerator(const Module *M) {
  // Enumerate the global variables.
  for (Module::const_global_iterator I = M->global_begin(),
         E = M->global_end(); I != E; ++I)
    EnumerateValue(I);

  // Enumerate the functions.
  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I) {
    EnumerateValue(I);
    EnumerateAttributes(cast<Function>(I)->getAttributes());
  }

  // Enumerate the aliases.
  for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
       I != E; ++I)
    EnumerateValue(I);

  // Remember what is the cutoff between globalvalue's and other constants.
  unsigned FirstConstant = Values.size();

  // Enumerate the global variable initializers.
  for (Module::const_global_iterator I = M->global_begin(),
         E = M->global_end(); I != E; ++I)
    if (I->hasInitializer())
      EnumerateValue(I->getInitializer());

  // Enumerate the aliasees.
  for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
       I != E; ++I)
    EnumerateValue(I->getAliasee());

  // Insert constants and metadata that are named at module level into the slot 
  // pool so that the module symbol table can refer to them...
  EnumerateValueSymbolTable(M->getValueSymbolTable());
  EnumerateNamedMetadata(M);

  SmallVector<std::pair<unsigned, MDNode*>, 8> MDs;

  // Enumerate types used by function bodies and argument lists.
  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {

    for (Function::const_arg_iterator I = F->arg_begin(), E = F->arg_end();
         I != E; ++I)
      EnumerateType(I->getType());

    for (Function::const_iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
      for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I!=E;++I){
        for (User::const_op_iterator OI = I->op_begin(), E = I->op_end();
             OI != E; ++OI) {
          if (MDNode *MD = dyn_cast<MDNode>(*OI))
            if (MD->isFunctionLocal() && MD->getFunction())
              // These will get enumerated during function-incorporation.
              continue;
          EnumerateOperandType(*OI);
        }
        EnumerateType(I->getType());
        if (const CallInst *CI = dyn_cast<CallInst>(I))
          EnumerateAttributes(CI->getAttributes());
        else if (const InvokeInst *II = dyn_cast<InvokeInst>(I))
          EnumerateAttributes(II->getAttributes());

        // Enumerate metadata attached with this instruction.
        MDs.clear();
        I->getAllMetadataOtherThanDebugLoc(MDs);
        for (unsigned i = 0, e = MDs.size(); i != e; ++i)
          EnumerateMetadata(MDs[i].second);
        
        if (!I->getDebugLoc().isUnknown()) {
          MDNode *Scope, *IA;
          I->getDebugLoc().getScopeAndInlinedAt(Scope, IA, I->getContext());
          if (Scope) EnumerateMetadata(Scope);
          if (IA) EnumerateMetadata(IA);
        }
      }
  }

  // Optimize constant ordering.
  OptimizeConstants(FirstConstant, Values.size());
}
Beispiel #12
0
SDValue
Cpu0TargetLowering::LowerCall(SDValue InChain, SDValue Callee,
                              CallingConv::ID CallConv, bool isVarArg,
                              bool doesNotRet, bool &isTailCall,
                              const SmallVectorImpl<ISD::OutputArg> &Outs,
                              const SmallVectorImpl<SDValue> &OutVals,
                              const SmallVectorImpl<ISD::InputArg> &Ins,
                              DebugLoc dl, SelectionDAG &DAG,
                              SmallVectorImpl<SDValue> &InVals) const {
  // Cpu0 target does not yet support tail call optimization.
  isTailCall = false;

  MachineFunction &MF = DAG.getMachineFunction();
  MachineFrameInfo *MFI = MF.getFrameInfo();
  const TargetFrameLowering *TFL = MF.getTarget().getFrameLowering();
  bool IsPIC = getTargetMachine().getRelocationModel() == Reloc::PIC_;
  Cpu0FunctionInfo *Cpu0FI = MF.getInfo<Cpu0FunctionInfo>();

  // Analyze operands of the call, assigning locations to each operand.
  SmallVector<CCValAssign, 16> ArgLocs;
  CCState CCInfo(CallConv, isVarArg, DAG.getMachineFunction(),
                 getTargetMachine(), ArgLocs, *DAG.getContext());

  CCInfo.AnalyzeCallOperands(Outs, CC_Cpu0);

  // Get a count of how many bytes are to be pushed on the stack.
  unsigned NextStackOffset = CCInfo.getNextStackOffset();

  // If this is the first call, create a stack frame object that points to
  // a location to which .cprestore saves $gp.
  if (IsPIC && Cpu0FI->globalBaseRegFixed() && !Cpu0FI->getGPFI())
    Cpu0FI->setGPFI(MFI->CreateFixedObject(4, 0, true));
  // Get the frame index of the stack frame object that points to the location
  // of dynamically allocated area on the stack.
  int DynAllocFI = Cpu0FI->getDynAllocFI();
  unsigned MaxCallFrameSize = Cpu0FI->getMaxCallFrameSize();

  if (MaxCallFrameSize < NextStackOffset) {
    Cpu0FI->setMaxCallFrameSize(NextStackOffset);

    // Set the offsets relative to $sp of the $gp restore slot and dynamically
    // allocated stack space. These offsets must be aligned to a boundary
    // determined by the stack alignment of the ABI.
    unsigned StackAlignment = TFL->getStackAlignment();
    NextStackOffset = (NextStackOffset + StackAlignment - 1) /
                      StackAlignment * StackAlignment;

    MFI->setObjectOffset(DynAllocFI, NextStackOffset);
  }
  // Chain is the output chain of the last Load/Store or CopyToReg node.
  // ByValChain is the output chain of the last Memcpy node created for copying
  // byval arguments to the stack.
  SDValue Chain, CallSeqStart, ByValChain;
  SDValue NextStackOffsetVal = DAG.getIntPtrConstant(NextStackOffset, true);
  Chain = CallSeqStart = DAG.getCALLSEQ_START(InChain, NextStackOffsetVal);
  ByValChain = InChain;

  // With EABI is it possible to have 16 args on registers.
  SmallVector<std::pair<unsigned, SDValue>, 16> RegsToPass;
  SmallVector<SDValue, 8> MemOpChains;

  int FirstFI = -MFI->getNumFixedObjects() - 1, LastFI = 0;

  // Walk the register/memloc assignments, inserting copies/loads.
  for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
    SDValue Arg = OutVals[i];
    CCValAssign &VA = ArgLocs[i];
    MVT ValVT = VA.getValVT(), LocVT = VA.getLocVT();
    ISD::ArgFlagsTy Flags = Outs[i].Flags;

    // ByVal Arg.
    if (Flags.isByVal()) {
      assert("!!!Error!!!, Flags.isByVal()==true");
      assert(Flags.getByValSize() &&
             "ByVal args of size 0 should have been ignored by front-end.");
      continue;
    }

    // Register can't get to this point...
    assert(VA.isMemLoc());

    // Create the frame index object for this incoming parameter
    LastFI = MFI->CreateFixedObject(ValVT.getSizeInBits()/8,
                                    VA.getLocMemOffset(), true);
    SDValue PtrOff = DAG.getFrameIndex(LastFI, getPointerTy());

    // emit ISD::STORE whichs stores the
    // parameter value to a stack Location
    MemOpChains.push_back(DAG.getStore(Chain, dl, Arg, PtrOff,
                                       MachinePointerInfo(), false, false, 0));
  }

  // Extend range of indices of frame objects for outgoing arguments that were
  // created during this function call. Skip this step if no such objects were
  // created.
  if (LastFI)
    Cpu0FI->extendOutArgFIRange(FirstFI, LastFI);

  // If a memcpy has been created to copy a byval arg to a stack, replace the
  // chain input of CallSeqStart with ByValChain.
  if (InChain != ByValChain)
    DAG.UpdateNodeOperands(CallSeqStart.getNode(), ByValChain,
                           NextStackOffsetVal);

  // Transform all store nodes into one single node because all store
  // nodes are independent of each other.
  if (!MemOpChains.empty())
    Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other,
                        &MemOpChains[0], MemOpChains.size());

  // If the callee is a GlobalAddress/ExternalSymbol node (quite common, every
  // direct call is) turn it into a TargetGlobalAddress/TargetExternalSymbol
  // node so that legalize doesn't hack it.
  unsigned char OpFlag;
  bool IsPICCall = IsPIC; // true if calls are translated to jalr $25
  bool GlobalOrExternal = false;
  SDValue CalleeLo;

  if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee)) {
    OpFlag = IsPICCall ? Cpu0II::MO_GOT_CALL : Cpu0II::MO_NO_FLAG;
    Callee = DAG.getTargetGlobalAddress(G->getGlobal(), dl,
                                          getPointerTy(), 0, OpFlag);
    GlobalOrExternal = true;
  }
  else if (ExternalSymbolSDNode *S = dyn_cast<ExternalSymbolSDNode>(Callee)) {
    if (!IsPIC) // static
      OpFlag = Cpu0II::MO_NO_FLAG;
    else // O32 & PIC
      OpFlag = Cpu0II::MO_GOT_CALL;
    Callee = DAG.getTargetExternalSymbol(S->getSymbol(), getPointerTy(),
                                         OpFlag);
    GlobalOrExternal = true;
  }

  SDValue InFlag;

  // Create nodes that load address of callee and copy it to T9
  if (IsPICCall) {
    if (GlobalOrExternal) {
      // Load callee address
      Callee = DAG.getNode(Cpu0ISD::Wrapper, dl, getPointerTy(),
                           GetGlobalReg(DAG, getPointerTy()), Callee);
      SDValue LoadValue = DAG.getLoad(getPointerTy(), dl, DAG.getEntryNode(),
                                      Callee, MachinePointerInfo::getGOT(),
                                      false, false, false, 0);

      // Use GOT+LO if callee has internal linkage.
      if (CalleeLo.getNode()) {
        SDValue Lo = DAG.getNode(Cpu0ISD::Lo, dl, getPointerTy(), CalleeLo);
        Callee = DAG.getNode(ISD::ADD, dl, getPointerTy(), LoadValue, Lo);
      } else
        Callee = LoadValue;
    }
  }

  // T9 should contain the address of the callee function if
  // -reloction-model=pic or it is an indirect call.
  if (IsPICCall || !GlobalOrExternal) {
    // copy to T9
    unsigned T9Reg = Cpu0::T9;
    Chain = DAG.getCopyToReg(Chain, dl, T9Reg, Callee, SDValue(0, 0));
    InFlag = Chain.getValue(1);
    Callee = DAG.getRegister(T9Reg, getPointerTy());
  }

  // Cpu0JmpLink = #chain, #target_address, #opt_in_flags...
  //             = Chain, Callee, Reg#1, Reg#2, ...
  //
  // Returns a chain & a flag for retval copy to use.
  SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Glue);
  SmallVector<SDValue, 8> Ops;
  Ops.push_back(Chain);
  Ops.push_back(Callee);

  // Add argument registers to the end of the list so that they are
  // known live into the call.
  for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i)
    Ops.push_back(DAG.getRegister(RegsToPass[i].first,
                                  RegsToPass[i].second.getValueType()));

  // Add a register mask operand representing the call-preserved registers.
  const TargetRegisterInfo *TRI = getTargetMachine().getRegisterInfo();
  const uint32_t *Mask = TRI->getCallPreservedMask(CallConv);
  assert(Mask && "Missing call preserved mask for calling convention");
  Ops.push_back(DAG.getRegisterMask(Mask));

  if (InFlag.getNode())
    Ops.push_back(InFlag);

  Chain  = DAG.getNode(Cpu0ISD::JmpLink, dl, NodeTys, &Ops[0], Ops.size());
  InFlag = Chain.getValue(1);

  // Create the CALLSEQ_END node.
  Chain = DAG.getCALLSEQ_END(Chain,
                             DAG.getIntPtrConstant(NextStackOffset, true),
                             DAG.getIntPtrConstant(0, true), InFlag);
  InFlag = Chain.getValue(1);

  // Handle result values, copying them out of physregs into vregs that we
  // return.
  return LowerCallResult(Chain, InFlag, CallConv, isVarArg,
                         Ins, dl, DAG, InVals);
}
/// ParseAsmStatement - Parse a GNU extended asm statement.
///       asm-statement:
///         gnu-asm-statement
///         ms-asm-statement
///
/// [GNU] gnu-asm-statement:
///         'asm' type-qualifier[opt] '(' asm-argument ')' ';'
///
/// [GNU] asm-argument:
///         asm-string-literal
///         asm-string-literal ':' asm-operands[opt]
///         asm-string-literal ':' asm-operands[opt] ':' asm-operands[opt]
///         asm-string-literal ':' asm-operands[opt] ':' asm-operands[opt]
///                 ':' asm-clobbers
///
/// [GNU] asm-clobbers:
///         asm-string-literal
///         asm-clobbers ',' asm-string-literal
///
StmtResult Parser::ParseAsmStatement(bool &msAsm) {
  assert(Tok.is(tok::kw_asm) && "Not an asm stmt");
  SourceLocation AsmLoc = ConsumeToken();

  if (getLangOpts().AsmBlocks && !isGCCAsmStatement(Tok)) {
    msAsm = true;
    return ParseMicrosoftAsmStatement(AsmLoc);
  }

  DeclSpec DS(AttrFactory);
  SourceLocation Loc = Tok.getLocation();
  ParseTypeQualifierListOpt(DS, AR_VendorAttributesParsed);

  // GNU asms accept, but warn, about type-qualifiers other than volatile.
  if (DS.getTypeQualifiers() & DeclSpec::TQ_const)
    Diag(Loc, diag::warn_asm_qualifier_ignored) << "const";
  if (DS.getTypeQualifiers() & DeclSpec::TQ_restrict)
    Diag(Loc, diag::warn_asm_qualifier_ignored) << "restrict";
  // FIXME: Once GCC supports _Atomic, check whether it permits it here.
  if (DS.getTypeQualifiers() & DeclSpec::TQ_atomic)
    Diag(Loc, diag::warn_asm_qualifier_ignored) << "_Atomic";

  // Remember if this was a volatile asm.
  bool isVolatile = DS.getTypeQualifiers() & DeclSpec::TQ_volatile;

  // TODO: support "asm goto" constructs (PR#9295).
  if (Tok.is(tok::kw_goto)) {
    Diag(Tok, diag::err_asm_goto_not_supported_yet);
    SkipUntil(tok::r_paren, StopAtSemi);
    return StmtError();
  }

  if (Tok.isNot(tok::l_paren)) {
    Diag(Tok, diag::err_expected_lparen_after) << "asm";
    SkipUntil(tok::r_paren, StopAtSemi);
    return StmtError();
  }
  BalancedDelimiterTracker T(*this, tok::l_paren);
  T.consumeOpen();

  ExprResult AsmString(ParseAsmStringLiteral());

  // Check if GNU-style InlineAsm is disabled.
  // Error on anything other than empty string.
  if (!(getLangOpts().GNUAsm || AsmString.isInvalid())) {
    const auto *SL = cast<StringLiteral>(AsmString.get());
    if (!SL->getString().trim().empty())
      Diag(Loc, diag::err_gnu_inline_asm_disabled);
  }

  if (AsmString.isInvalid()) {
    // Consume up to and including the closing paren.
    T.skipToEnd();
    return StmtError();
  }

  SmallVector<IdentifierInfo *, 4> Names;
  ExprVector Constraints;
  ExprVector Exprs;
  ExprVector Clobbers;

  if (Tok.is(tok::r_paren)) {
    // We have a simple asm expression like 'asm("foo")'.
    T.consumeClose();
    return Actions.ActOnGCCAsmStmt(AsmLoc, /*isSimple*/ true, isVolatile,
                                   /*NumOutputs*/ 0, /*NumInputs*/ 0, nullptr,
                                   Constraints, Exprs, AsmString.get(),
                                   Clobbers, T.getCloseLocation());
  }

  // Parse Outputs, if present.
  bool AteExtraColon = false;
  if (Tok.is(tok::colon) || Tok.is(tok::coloncolon)) {
    // In C++ mode, parse "::" like ": :".
    AteExtraColon = Tok.is(tok::coloncolon);
    ConsumeToken();

    if (!AteExtraColon && ParseAsmOperandsOpt(Names, Constraints, Exprs))
      return StmtError();
  }

  unsigned NumOutputs = Names.size();

  // Parse Inputs, if present.
  if (AteExtraColon || Tok.is(tok::colon) || Tok.is(tok::coloncolon)) {
    // In C++ mode, parse "::" like ": :".
    if (AteExtraColon)
      AteExtraColon = false;
    else {
      AteExtraColon = Tok.is(tok::coloncolon);
      ConsumeToken();
    }

    if (!AteExtraColon && ParseAsmOperandsOpt(Names, Constraints, Exprs))
      return StmtError();
  }

  assert(Names.size() == Constraints.size() &&
         Constraints.size() == Exprs.size() && "Input operand size mismatch!");

  unsigned NumInputs = Names.size() - NumOutputs;

  // Parse the clobbers, if present.
  if (AteExtraColon || Tok.is(tok::colon)) {
    if (!AteExtraColon)
      ConsumeToken();

    // Parse the asm-string list for clobbers if present.
    if (Tok.isNot(tok::r_paren)) {
      while (1) {
        ExprResult Clobber(ParseAsmStringLiteral());

        if (Clobber.isInvalid())
          break;

        Clobbers.push_back(Clobber.get());

        if (!TryConsumeToken(tok::comma))
          break;
      }
    }
  }

  T.consumeClose();
  return Actions.ActOnGCCAsmStmt(
      AsmLoc, false, isVolatile, NumOutputs, NumInputs, Names.data(),
      Constraints, Exprs, AsmString.get(), Clobbers, T.getCloseLocation());
}
Beispiel #14
0
/// PropagateConstantsIntoArguments - Look at all uses of the specified
/// function.  If all uses are direct call sites, and all pass a particular
/// constant in for an argument, propagate that constant in as the argument.
///
bool IPCP::PropagateConstantsIntoArguments(Function &F) {
  if (F.arg_empty() || F.use_empty()) return false; // No arguments? Early exit.

  // For each argument, keep track of its constant value and whether it is a
  // constant or not.  The bool is driven to true when found to be non-constant.
  SmallVector<std::pair<Constant*, bool>, 16> ArgumentConstants;
  ArgumentConstants.resize(F.arg_size());

  unsigned NumNonconstant = 0;
  for (Value::use_iterator UI = F.use_begin(), E = F.use_end(); UI != E; ++UI) {
    User *U = *UI;
    // Ignore blockaddress uses.
    if (isa<BlockAddress>(U)) continue;
    
    // Used by a non-instruction, or not the callee of a function, do not
    // transform.
    if (!isa<CallInst>(U) && !isa<InvokeInst>(U))
      return false;
    
    CallSite CS(cast<Instruction>(U));
    if (!CS.isCallee(UI))
      return false;

    // Check out all of the potentially constant arguments.  Note that we don't
    // inspect varargs here.
    CallSite::arg_iterator AI = CS.arg_begin();
    Function::arg_iterator Arg = F.arg_begin();
    for (unsigned i = 0, e = ArgumentConstants.size(); i != e;
         ++i, ++AI, ++Arg) {
      
      // If this argument is known non-constant, ignore it.
      if (ArgumentConstants[i].second)
        continue;
      
      Constant *C = dyn_cast<Constant>(*AI);
      if (C && ArgumentConstants[i].first == 0) {
        ArgumentConstants[i].first = C;   // First constant seen.
      } else if (C && ArgumentConstants[i].first == C) {
        // Still the constant value we think it is.
      } else if (*AI == &*Arg) {
        // Ignore recursive calls passing argument down.
      } else {
        // Argument became non-constant.  If all arguments are non-constant now,
        // give up on this function.
        if (++NumNonconstant == ArgumentConstants.size())
          return false;
        ArgumentConstants[i].second = true;
      }
    }
  }

  // If we got to this point, there is a constant argument!
  assert(NumNonconstant != ArgumentConstants.size());
  bool MadeChange = false;
  Function::arg_iterator AI = F.arg_begin();
  for (unsigned i = 0, e = ArgumentConstants.size(); i != e; ++i, ++AI) {
    // Do we have a constant argument?
    if (ArgumentConstants[i].second || AI->use_empty() ||
        (AI->hasByValAttr() && !F.onlyReadsMemory()))
      continue;
  
    Value *V = ArgumentConstants[i].first;
    if (V == 0) V = UndefValue::get(AI->getType());
    AI->replaceAllUsesWith(V);
    ++NumArgumentsProped;
    MadeChange = true;
  }
  return MadeChange;
}
Beispiel #15
0
/// spillAroundUses - insert spill code around each use of Reg.
void InlineSpiller::spillAroundUses(unsigned Reg) {
  DEBUG(dbgs() << "spillAroundUses " << PrintReg(Reg) << '\n');
  LiveInterval &OldLI = LIS.getInterval(Reg);

  // Iterate over instructions using Reg.
  for (MachineRegisterInfo::reg_iterator RegI = MRI.reg_begin(Reg);
       MachineInstr *MI = RegI.skipBundle();) {

    // Debug values are not allowed to affect codegen.
    if (MI->isDebugValue()) {
      // Modify DBG_VALUE now that the value is in a spill slot.
      uint64_t Offset = MI->getOperand(1).getImm();
      const MDNode *MDPtr = MI->getOperand(2).getMetadata();
      DebugLoc DL = MI->getDebugLoc();
      DEBUG(dbgs() << "Modifying debug info due to spill:" << "\t" << *MI);
      MachineBasicBlock *MBB = MI->getParent();
      BuildMI(*MBB, MBB->erase(MI), DL, TII.get(TargetOpcode::DBG_VALUE))
          .addFrameIndex(StackSlot).addImm(Offset).addMetadata(MDPtr);
      continue;
    }

    // Ignore copies to/from snippets. We'll delete them.
    if (SnippetCopies.count(MI))
      continue;

    // Stack slot accesses may coalesce away.
    if (coalesceStackAccess(MI, Reg))
      continue;

    // Analyze instruction.
    SmallVector<std::pair<MachineInstr*, unsigned>, 8> Ops;
    MIBundleOperands::VirtRegInfo RI =
      MIBundleOperands(MI).analyzeVirtReg(Reg, &Ops);

    // Find the slot index where this instruction reads and writes OldLI.
    // This is usually the def slot, except for tied early clobbers.
    SlotIndex Idx = LIS.getInstructionIndex(MI).getRegSlot();
    if (VNInfo *VNI = OldLI.getVNInfoAt(Idx.getRegSlot(true)))
      if (SlotIndex::isSameInstr(Idx, VNI->def))
        Idx = VNI->def;

    // Check for a sibling copy.
    unsigned SibReg = isFullCopyOf(MI, Reg);
    if (SibReg && isSibling(SibReg)) {
      // This may actually be a copy between snippets.
      if (isRegToSpill(SibReg)) {
        DEBUG(dbgs() << "Found new snippet copy: " << *MI);
        SnippetCopies.insert(MI);
        continue;
      }
      if (RI.Writes) {
        // Hoist the spill of a sib-reg copy.
        if (hoistSpill(OldLI, MI)) {
          // This COPY is now dead, the value is already in the stack slot.
          MI->getOperand(0).setIsDead();
          DeadDefs.push_back(MI);
          continue;
        }
      } else {
        // This is a reload for a sib-reg copy. Drop spills downstream.
        LiveInterval &SibLI = LIS.getInterval(SibReg);
        eliminateRedundantSpills(SibLI, SibLI.getVNInfoAt(Idx));
        // The COPY will fold to a reload below.
      }
    }

    // Attempt to fold memory ops.
    if (foldMemoryOperand(Ops))
      continue;

    // Allocate interval around instruction.
    // FIXME: Infer regclass from instruction alone.
    LiveInterval &NewLI = Edit->createFrom(Reg);
    NewLI.markNotSpillable();

    if (RI.Reads)
      insertReload(NewLI, Idx, MI);

    // Rewrite instruction operands.
    bool hasLiveDef = false;
    for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
      MachineOperand &MO = Ops[i].first->getOperand(Ops[i].second);
      MO.setReg(NewLI.reg);
      if (MO.isUse()) {
        if (!Ops[i].first->isRegTiedToDefOperand(Ops[i].second))
          MO.setIsKill();
      } else {
        if (!MO.isDead())
          hasLiveDef = true;
      }
    }
    DEBUG(dbgs() << "\trewrite: " << Idx << '\t' << *MI);

    // FIXME: Use a second vreg if instruction has no tied ops.
    if (RI.Writes) {
      if (hasLiveDef)
        insertSpill(NewLI, OldLI, Idx, MI);
      else {
        // This instruction defines a dead value.  We don't need to spill it,
        // but do create a live range for the dead value.
        VNInfo *VNI = NewLI.getNextValue(Idx, LIS.getVNInfoAllocator());
        NewLI.addRange(LiveRange(Idx, Idx.getDeadSlot(), VNI));
      }
    }

    DEBUG(dbgs() << "\tinterval: " << NewLI << '\n');
  }
}
Instruction *InstCombiner::visitAllocaInst(AllocaInst &AI) {
  // Ensure that the alloca array size argument has type intptr_t, so that
  // any casting is exposed early.
  if (DL) {
    Type *IntPtrTy = DL->getIntPtrType(AI.getType());
    if (AI.getArraySize()->getType() != IntPtrTy) {
      Value *V = Builder->CreateIntCast(AI.getArraySize(),
                                        IntPtrTy, false);
      AI.setOperand(0, V);
      return &AI;
    }
  }

  // Convert: alloca Ty, C - where C is a constant != 1 into: alloca [C x Ty], 1
  if (AI.isArrayAllocation()) {  // Check C != 1
    if (const ConstantInt *C = dyn_cast<ConstantInt>(AI.getArraySize())) {
      Type *NewTy =
        ArrayType::get(AI.getAllocatedType(), C->getZExtValue());
      AllocaInst *New = Builder->CreateAlloca(NewTy, nullptr, AI.getName());
      New->setAlignment(AI.getAlignment());

      // Scan to the end of the allocation instructions, to skip over a block of
      // allocas if possible...also skip interleaved debug info
      //
      BasicBlock::iterator It = New;
      while (isa<AllocaInst>(*It) || isa<DbgInfoIntrinsic>(*It)) ++It;

      // Now that I is pointing to the first non-allocation-inst in the block,
      // insert our getelementptr instruction...
      //
      Type *IdxTy = DL
                  ? DL->getIntPtrType(AI.getType())
                  : Type::getInt64Ty(AI.getContext());
      Value *NullIdx = Constant::getNullValue(IdxTy);
      Value *Idx[2] = { NullIdx, NullIdx };
      Instruction *GEP =
        GetElementPtrInst::CreateInBounds(New, Idx, New->getName() + ".sub");
      InsertNewInstBefore(GEP, *It);

      // Now make everything use the getelementptr instead of the original
      // allocation.
      return ReplaceInstUsesWith(AI, GEP);
    } else if (isa<UndefValue>(AI.getArraySize())) {
      return ReplaceInstUsesWith(AI, Constant::getNullValue(AI.getType()));
    }
  }

  if (DL && AI.getAllocatedType()->isSized()) {
    // If the alignment is 0 (unspecified), assign it the preferred alignment.
    if (AI.getAlignment() == 0)
      AI.setAlignment(DL->getPrefTypeAlignment(AI.getAllocatedType()));

    // Move all alloca's of zero byte objects to the entry block and merge them
    // together.  Note that we only do this for alloca's, because malloc should
    // allocate and return a unique pointer, even for a zero byte allocation.
    if (DL->getTypeAllocSize(AI.getAllocatedType()) == 0) {
      // For a zero sized alloca there is no point in doing an array allocation.
      // This is helpful if the array size is a complicated expression not used
      // elsewhere.
      if (AI.isArrayAllocation()) {
        AI.setOperand(0, ConstantInt::get(AI.getArraySize()->getType(), 1));
        return &AI;
      }

      // Get the first instruction in the entry block.
      BasicBlock &EntryBlock = AI.getParent()->getParent()->getEntryBlock();
      Instruction *FirstInst = EntryBlock.getFirstNonPHIOrDbg();
      if (FirstInst != &AI) {
        // If the entry block doesn't start with a zero-size alloca then move
        // this one to the start of the entry block.  There is no problem with
        // dominance as the array size was forced to a constant earlier already.
        AllocaInst *EntryAI = dyn_cast<AllocaInst>(FirstInst);
        if (!EntryAI || !EntryAI->getAllocatedType()->isSized() ||
            DL->getTypeAllocSize(EntryAI->getAllocatedType()) != 0) {
          AI.moveBefore(FirstInst);
          return &AI;
        }

        // If the alignment of the entry block alloca is 0 (unspecified),
        // assign it the preferred alignment.
        if (EntryAI->getAlignment() == 0)
          EntryAI->setAlignment(
            DL->getPrefTypeAlignment(EntryAI->getAllocatedType()));
        // Replace this zero-sized alloca with the one at the start of the entry
        // block after ensuring that the address will be aligned enough for both
        // types.
        unsigned MaxAlign = std::max(EntryAI->getAlignment(),
                                     AI.getAlignment());
        EntryAI->setAlignment(MaxAlign);
        if (AI.getType() != EntryAI->getType())
          return new BitCastInst(EntryAI, AI.getType());
        return ReplaceInstUsesWith(AI, EntryAI);
      }
    }
  }

  if (AI.getAlignment()) {
    // Check to see if this allocation is only modified by a memcpy/memmove from
    // a constant global whose alignment is equal to or exceeds that of the
    // allocation.  If this is the case, we can change all users to use
    // the constant global instead.  This is commonly produced by the CFE by
    // constructs like "void foo() { int A[] = {1,2,3,4,5,6,7,8,9...}; }" if 'A'
    // is only subsequently read.
    SmallVector<Instruction *, 4> ToDelete;
    if (MemTransferInst *Copy = isOnlyCopiedFromConstantGlobal(&AI, ToDelete)) {
      unsigned SourceAlign = getOrEnforceKnownAlignment(Copy->getSource(),
                                                        AI.getAlignment(),
                                                        DL, AT, &AI, DT);
      if (AI.getAlignment() <= SourceAlign) {
        DEBUG(dbgs() << "Found alloca equal to global: " << AI << '\n');
        DEBUG(dbgs() << "  memcpy = " << *Copy << '\n');
        for (unsigned i = 0, e = ToDelete.size(); i != e; ++i)
          EraseInstFromFunction(*ToDelete[i]);
        Constant *TheSrc = cast<Constant>(Copy->getSource());
        Constant *Cast
          = ConstantExpr::getPointerBitCastOrAddrSpaceCast(TheSrc, AI.getType());
        Instruction *NewI = ReplaceInstUsesWith(AI, Cast);
        EraseInstFromFunction(*Copy);
        ++NumGlobalCopies;
        return NewI;
      }
    }
  }

  // At last, use the generic allocation site handler to aggressively remove
  // unused allocas.
  return visitAllocSite(AI);
}
Beispiel #17
0
/// reMaterializeFor - Attempt to rematerialize before MI instead of reloading.
bool InlineSpiller::reMaterializeFor(LiveInterval &VirtReg,
                                     MachineBasicBlock::iterator MI) {
  SlotIndex UseIdx = LIS.getInstructionIndex(MI).getRegSlot(true);
  VNInfo *ParentVNI = VirtReg.getVNInfoAt(UseIdx.getBaseIndex());

  if (!ParentVNI) {
    DEBUG(dbgs() << "\tadding <undef> flags: ");
    for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
      MachineOperand &MO = MI->getOperand(i);
      if (MO.isReg() && MO.isUse() && MO.getReg() == VirtReg.reg)
        MO.setIsUndef();
    }
    DEBUG(dbgs() << UseIdx << '\t' << *MI);
    return true;
  }

  if (SnippetCopies.count(MI))
    return false;

  // Use an OrigVNI from traceSiblingValue when ParentVNI is a sibling copy.
  LiveRangeEdit::Remat RM(ParentVNI);
  SibValueMap::const_iterator SibI = SibValues.find(ParentVNI);
  if (SibI != SibValues.end())
    RM.OrigMI = SibI->second.DefMI;
  if (!Edit->canRematerializeAt(RM, UseIdx, false)) {
    markValueUsed(&VirtReg, ParentVNI);
    DEBUG(dbgs() << "\tcannot remat for " << UseIdx << '\t' << *MI);
    return false;
  }

  // If the instruction also writes VirtReg.reg, it had better not require the
  // same register for uses and defs.
  SmallVector<std::pair<MachineInstr*, unsigned>, 8> Ops;
  MIBundleOperands::VirtRegInfo RI =
    MIBundleOperands(MI).analyzeVirtReg(VirtReg.reg, &Ops);
  if (RI.Tied) {
    markValueUsed(&VirtReg, ParentVNI);
    DEBUG(dbgs() << "\tcannot remat tied reg: " << UseIdx << '\t' << *MI);
    return false;
  }

  // Before rematerializing into a register for a single instruction, try to
  // fold a load into the instruction. That avoids allocating a new register.
  if (RM.OrigMI->canFoldAsLoad() &&
      foldMemoryOperand(Ops, RM.OrigMI)) {
    Edit->markRematerialized(RM.ParentVNI);
    ++NumFoldedLoads;
    return true;
  }

  // Alocate a new register for the remat.
  LiveInterval &NewLI = Edit->createFrom(Original);
  NewLI.markNotSpillable();

  // Finally we can rematerialize OrigMI before MI.
  SlotIndex DefIdx = Edit->rematerializeAt(*MI->getParent(), MI, NewLI.reg, RM,
                                           TRI);
  DEBUG(dbgs() << "\tremat:  " << DefIdx << '\t'
               << *LIS.getInstructionFromIndex(DefIdx));

  // Replace operands
  for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
    MachineOperand &MO = MI->getOperand(Ops[i].second);
    if (MO.isReg() && MO.isUse() && MO.getReg() == VirtReg.reg) {
      MO.setReg(NewLI.reg);
      MO.setIsKill();
    }
  }
  DEBUG(dbgs() << "\t        " << UseIdx << '\t' << *MI);

  VNInfo *DefVNI = NewLI.getNextValue(DefIdx, LIS.getVNInfoAllocator());
  NewLI.addRange(LiveRange(DefIdx, UseIdx.getRegSlot(), DefVNI));
  DEBUG(dbgs() << "\tinterval: " << NewLI << '\n');
  ++NumRemats;
  return true;
}
StmtResult Sema::ActOnGCCAsmStmt(SourceLocation AsmLoc, bool IsSimple,
                                 bool IsVolatile, unsigned NumOutputs,
                                 unsigned NumInputs, IdentifierInfo **Names,
                                 MultiExprArg constraints, MultiExprArg Exprs,
                                 Expr *asmString, MultiExprArg clobbers,
                                 SourceLocation RParenLoc) {
  unsigned NumClobbers = clobbers.size();
  StringLiteral **Constraints =
    reinterpret_cast<StringLiteral**>(constraints.data());
  StringLiteral *AsmString = cast<StringLiteral>(asmString);
  StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.data());

  SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos;

  // The parser verifies that there is a string literal here.
  assert(AsmString->isAscii());

  for (unsigned i = 0; i != NumOutputs; i++) {
    StringLiteral *Literal = Constraints[i];
    assert(Literal->isAscii());

    StringRef OutputName;
    if (Names[i])
      OutputName = Names[i]->getName();

    TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName);
    if (!Context.getTargetInfo().validateOutputConstraint(Info))
      return StmtError(Diag(Literal->getLocStart(),
                            diag::err_asm_invalid_output_constraint)
                       << Info.getConstraintStr());

    ExprResult ER = CheckPlaceholderExpr(Exprs[i]);
    if (ER.isInvalid())
      return StmtError();
    Exprs[i] = ER.get();

    // Check that the output exprs are valid lvalues.
    Expr *OutputExpr = Exprs[i];

    // Referring to parameters is not allowed in naked functions.
    if (CheckNakedParmReference(OutputExpr, *this))
      return StmtError();

    OutputConstraintInfos.push_back(Info);

    // If this is dependent, just continue.
    if (OutputExpr->isTypeDependent())
      continue;

    Expr::isModifiableLvalueResult IsLV =
        OutputExpr->isModifiableLvalue(Context, /*Loc=*/nullptr);
    switch (IsLV) {
    case Expr::MLV_Valid:
      // Cool, this is an lvalue.
      break;
    case Expr::MLV_ArrayType:
      // This is OK too.
      break;
    case Expr::MLV_LValueCast: {
      const Expr *LVal = OutputExpr->IgnoreParenNoopCasts(Context);
      if (!getLangOpts().HeinousExtensions) {
        Diag(LVal->getLocStart(), diag::err_invalid_asm_cast_lvalue)
            << OutputExpr->getSourceRange();
      } else {
        Diag(LVal->getLocStart(), diag::warn_invalid_asm_cast_lvalue)
            << OutputExpr->getSourceRange();
      }
      // Accept, even if we emitted an error diagnostic.
      break;
    }
    case Expr::MLV_IncompleteType:
    case Expr::MLV_IncompleteVoidType:
      if (RequireCompleteType(OutputExpr->getLocStart(), Exprs[i]->getType(),
                              diag::err_dereference_incomplete_type))
        return StmtError();
    default:
      return StmtError(Diag(OutputExpr->getLocStart(),
                            diag::err_asm_invalid_lvalue_in_output)
                       << OutputExpr->getSourceRange());
    }

    unsigned Size = Context.getTypeSize(OutputExpr->getType());
    if (!Context.getTargetInfo().validateOutputSize(Literal->getString(),
                                                    Size))
      return StmtError(Diag(OutputExpr->getLocStart(),
                            diag::err_asm_invalid_output_size)
                       << Info.getConstraintStr());
  }

  SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos;

  for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) {
    StringLiteral *Literal = Constraints[i];
    assert(Literal->isAscii());

    StringRef InputName;
    if (Names[i])
      InputName = Names[i]->getName();

    TargetInfo::ConstraintInfo Info(Literal->getString(), InputName);
    if (!Context.getTargetInfo().validateInputConstraint(OutputConstraintInfos.data(),
                                                NumOutputs, Info)) {
      return StmtError(Diag(Literal->getLocStart(),
                            diag::err_asm_invalid_input_constraint)
                       << Info.getConstraintStr());
    }

    ExprResult ER = CheckPlaceholderExpr(Exprs[i]);
    if (ER.isInvalid())
      return StmtError();
    Exprs[i] = ER.get();

    Expr *InputExpr = Exprs[i];

    // Referring to parameters is not allowed in naked functions.
    if (CheckNakedParmReference(InputExpr, *this))
      return StmtError();

    // Only allow void types for memory constraints.
    if (Info.allowsMemory() && !Info.allowsRegister()) {
      if (CheckAsmLValue(InputExpr, *this))
        return StmtError(Diag(InputExpr->getLocStart(),
                              diag::err_asm_invalid_lvalue_in_input)
                         << Info.getConstraintStr()
                         << InputExpr->getSourceRange());
    } else if (Info.requiresImmediateConstant() && !Info.allowsRegister()) {
      llvm::APSInt Result;
      if (!InputExpr->EvaluateAsInt(Result, Context))
        return StmtError(
            Diag(InputExpr->getLocStart(), diag::err_asm_invalid_type_in_input)
            << InputExpr->getType() << Info.getConstraintStr()
            << InputExpr->getSourceRange());
      if (Result.slt(Info.getImmConstantMin()) ||
          Result.sgt(Info.getImmConstantMax()))
        return StmtError(Diag(InputExpr->getLocStart(),
                              diag::err_invalid_asm_value_for_constraint)
                         << Result.toString(10) << Info.getConstraintStr()
                         << InputExpr->getSourceRange());

    } else {
      ExprResult Result = DefaultFunctionArrayLvalueConversion(Exprs[i]);
      if (Result.isInvalid())
        return StmtError();

      Exprs[i] = Result.get();
    }

    if (Info.allowsRegister()) {
      if (InputExpr->getType()->isVoidType()) {
        return StmtError(Diag(InputExpr->getLocStart(),
                              diag::err_asm_invalid_type_in_input)
          << InputExpr->getType() << Info.getConstraintStr()
          << InputExpr->getSourceRange());
      }
    }

    InputConstraintInfos.push_back(Info);

    const Type *Ty = Exprs[i]->getType().getTypePtr();
    if (Ty->isDependentType())
      continue;

    if (!Ty->isVoidType() || !Info.allowsMemory())
      if (RequireCompleteType(InputExpr->getLocStart(), Exprs[i]->getType(),
                              diag::err_dereference_incomplete_type))
        return StmtError();

    unsigned Size = Context.getTypeSize(Ty);
    if (!Context.getTargetInfo().validateInputSize(Literal->getString(),
                                                   Size))
      return StmtError(Diag(InputExpr->getLocStart(),
                            diag::err_asm_invalid_input_size)
                       << Info.getConstraintStr());
  }

  // Check that the clobbers are valid.
  for (unsigned i = 0; i != NumClobbers; i++) {
    StringLiteral *Literal = Clobbers[i];
    assert(Literal->isAscii());

    StringRef Clobber = Literal->getString();

    if (!Context.getTargetInfo().isValidClobber(Clobber))
      return StmtError(Diag(Literal->getLocStart(),
                  diag::err_asm_unknown_register_name) << Clobber);
  }

  GCCAsmStmt *NS =
    new (Context) GCCAsmStmt(Context, AsmLoc, IsSimple, IsVolatile, NumOutputs,
                             NumInputs, Names, Constraints, Exprs.data(),
                             AsmString, NumClobbers, Clobbers, RParenLoc);
  // Validate the asm string, ensuring it makes sense given the operands we
  // have.
  SmallVector<GCCAsmStmt::AsmStringPiece, 8> Pieces;
  unsigned DiagOffs;
  if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) {
    Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID)
           << AsmString->getSourceRange();
    return StmtError();
  }

  // Validate constraints and modifiers.
  for (unsigned i = 0, e = Pieces.size(); i != e; ++i) {
    GCCAsmStmt::AsmStringPiece &Piece = Pieces[i];
    if (!Piece.isOperand()) continue;

    // Look for the correct constraint index.
    unsigned Idx = 0;
    unsigned ConstraintIdx = 0;
    for (unsigned i = 0, e = NS->getNumOutputs(); i != e; ++i, ++ConstraintIdx) {
      TargetInfo::ConstraintInfo &Info = OutputConstraintInfos[i];
      if (Idx == Piece.getOperandNo())
        break;
      ++Idx;

      if (Info.isReadWrite()) {
        if (Idx == Piece.getOperandNo())
          break;
        ++Idx;
      }
    }

    for (unsigned i = 0, e = NS->getNumInputs(); i != e; ++i, ++ConstraintIdx) {
      TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i];
      if (Idx == Piece.getOperandNo())
        break;
      ++Idx;

      if (Info.isReadWrite()) {
        if (Idx == Piece.getOperandNo())
          break;
        ++Idx;
      }
    }

    // Now that we have the right indexes go ahead and check.
    StringLiteral *Literal = Constraints[ConstraintIdx];
    const Type *Ty = Exprs[ConstraintIdx]->getType().getTypePtr();
    if (Ty->isDependentType() || Ty->isIncompleteType())
      continue;

    unsigned Size = Context.getTypeSize(Ty);
    std::string SuggestedModifier;
    if (!Context.getTargetInfo().validateConstraintModifier(
            Literal->getString(), Piece.getModifier(), Size,
            SuggestedModifier)) {
      Diag(Exprs[ConstraintIdx]->getLocStart(),
           diag::warn_asm_mismatched_size_modifier);

      if (!SuggestedModifier.empty()) {
        auto B = Diag(Piece.getRange().getBegin(),
                      diag::note_asm_missing_constraint_modifier)
                 << SuggestedModifier;
        SuggestedModifier = "%" + SuggestedModifier + Piece.getString();
        B.AddFixItHint(FixItHint::CreateReplacement(Piece.getRange(),
                                                    SuggestedModifier));
      }
    }
  }

  // Validate tied input operands for type mismatches.
  unsigned NumAlternatives = ~0U;
  for (unsigned i = 0, e = OutputConstraintInfos.size(); i != e; ++i) {
    TargetInfo::ConstraintInfo &Info = OutputConstraintInfos[i];
    StringRef ConstraintStr = Info.getConstraintStr();
    unsigned AltCount = ConstraintStr.count(',') + 1;
    if (NumAlternatives == ~0U)
      NumAlternatives = AltCount;
    else if (NumAlternatives != AltCount)
      return StmtError(Diag(NS->getOutputExpr(i)->getLocStart(),
                            diag::err_asm_unexpected_constraint_alternatives)
                       << NumAlternatives << AltCount);
  }
  for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) {
    TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i];
    StringRef ConstraintStr = Info.getConstraintStr();
    unsigned AltCount = ConstraintStr.count(',') + 1;
    if (NumAlternatives == ~0U)
      NumAlternatives = AltCount;
    else if (NumAlternatives != AltCount)
      return StmtError(Diag(NS->getInputExpr(i)->getLocStart(),
                            diag::err_asm_unexpected_constraint_alternatives)
                       << NumAlternatives << AltCount);

    // If this is a tied constraint, verify that the output and input have
    // either exactly the same type, or that they are int/ptr operands with the
    // same size (int/long, int*/long, are ok etc).
    if (!Info.hasTiedOperand()) continue;

    unsigned TiedTo = Info.getTiedOperand();
    unsigned InputOpNo = i+NumOutputs;
    Expr *OutputExpr = Exprs[TiedTo];
    Expr *InputExpr = Exprs[InputOpNo];

    if (OutputExpr->isTypeDependent() || InputExpr->isTypeDependent())
      continue;

    QualType InTy = InputExpr->getType();
    QualType OutTy = OutputExpr->getType();
    if (Context.hasSameType(InTy, OutTy))
      continue;  // All types can be tied to themselves.

    // Decide if the input and output are in the same domain (integer/ptr or
    // floating point.
    enum AsmDomain {
      AD_Int, AD_FP, AD_Other
    } InputDomain, OutputDomain;

    if (InTy->isIntegerType() || InTy->isPointerType())
      InputDomain = AD_Int;
    else if (InTy->isRealFloatingType())
      InputDomain = AD_FP;
    else
      InputDomain = AD_Other;

    if (OutTy->isIntegerType() || OutTy->isPointerType())
      OutputDomain = AD_Int;
    else if (OutTy->isRealFloatingType())
      OutputDomain = AD_FP;
    else
      OutputDomain = AD_Other;

    // They are ok if they are the same size and in the same domain.  This
    // allows tying things like:
    //   void* to int*
    //   void* to int            if they are the same size.
    //   double to long double   if they are the same size.
    //
    uint64_t OutSize = Context.getTypeSize(OutTy);
    uint64_t InSize = Context.getTypeSize(InTy);
    if (OutSize == InSize && InputDomain == OutputDomain &&
        InputDomain != AD_Other)
      continue;

    // If the smaller input/output operand is not mentioned in the asm string,
    // then we can promote the smaller one to a larger input and the asm string
    // won't notice.
    bool SmallerValueMentioned = false;

    // If this is a reference to the input and if the input was the smaller
    // one, then we have to reject this asm.
    if (isOperandMentioned(InputOpNo, Pieces)) {
      // This is a use in the asm string of the smaller operand.  Since we
      // codegen this by promoting to a wider value, the asm will get printed
      // "wrong".
      SmallerValueMentioned |= InSize < OutSize;
    }
    if (isOperandMentioned(TiedTo, Pieces)) {
      // If this is a reference to the output, and if the output is the larger
      // value, then it's ok because we'll promote the input to the larger type.
      SmallerValueMentioned |= OutSize < InSize;
    }

    // If the smaller value wasn't mentioned in the asm string, and if the
    // output was a register, just extend the shorter one to the size of the
    // larger one.
    if (!SmallerValueMentioned && InputDomain != AD_Other &&
        OutputConstraintInfos[TiedTo].allowsRegister())
      continue;

    // Either both of the operands were mentioned or the smaller one was
    // mentioned.  One more special case that we'll allow: if the tied input is
    // integer, unmentioned, and is a constant, then we'll allow truncating it
    // down to the size of the destination.
    if (InputDomain == AD_Int && OutputDomain == AD_Int &&
        !isOperandMentioned(InputOpNo, Pieces) &&
        InputExpr->isEvaluatable(Context)) {
      CastKind castKind =
        (OutTy->isBooleanType() ? CK_IntegralToBoolean : CK_IntegralCast);
      InputExpr = ImpCastExprToType(InputExpr, OutTy, castKind).get();
      Exprs[InputOpNo] = InputExpr;
      NS->setInputExpr(i, InputExpr);
      continue;
    }

    Diag(InputExpr->getLocStart(),
         diag::err_asm_tying_incompatible_types)
      << InTy << OutTy << OutputExpr->getSourceRange()
      << InputExpr->getSourceRange();
    return StmtError();
  }

  return NS;
}
ChainedIncludesSource *ChainedIncludesSource::create(CompilerInstance &CI) {

  std::vector<std::string> &includes = CI.getPreprocessorOpts().ChainedIncludes;
  assert(!includes.empty() && "No '-chain-include' in options!");

  llvm::OwningPtr<ChainedIncludesSource> source(new ChainedIncludesSource());
  InputKind IK = CI.getFrontendOpts().Inputs[0].first;

  SmallVector<llvm::MemoryBuffer *, 4> serialBufs;
  SmallVector<std::string, 4> serialBufNames;

  for (unsigned i = 0, e = includes.size(); i != e; ++i) {
    bool firstInclude = (i == 0);
    llvm::OwningPtr<CompilerInvocation> CInvok;
    CInvok.reset(new CompilerInvocation(CI.getInvocation()));
    
    CInvok->getPreprocessorOpts().ChainedIncludes.clear();
    CInvok->getPreprocessorOpts().ImplicitPCHInclude.clear();
    CInvok->getPreprocessorOpts().ImplicitPTHInclude.clear();
    CInvok->getPreprocessorOpts().DisablePCHValidation = true;
    CInvok->getPreprocessorOpts().Includes.clear();
    CInvok->getPreprocessorOpts().MacroIncludes.clear();
    CInvok->getPreprocessorOpts().Macros.clear();
    
    CInvok->getFrontendOpts().Inputs.clear();
    CInvok->getFrontendOpts().Inputs.push_back(std::make_pair(IK, includes[i]));

    TextDiagnosticPrinter *DiagClient =
      new TextDiagnosticPrinter(llvm::errs(), DiagnosticOptions());
    llvm::IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
    llvm::IntrusiveRefCntPtr<DiagnosticsEngine> Diags(
        new DiagnosticsEngine(DiagID, DiagClient));

    llvm::OwningPtr<CompilerInstance> Clang(new CompilerInstance());
    Clang->setInvocation(CInvok.take());
    Clang->setDiagnostics(Diags.getPtr());
    Clang->setTarget(TargetInfo::CreateTargetInfo(Clang->getDiagnostics(),
                                                  Clang->getTargetOpts()));
    Clang->createFileManager();
    Clang->createSourceManager(Clang->getFileManager());
    Clang->createPreprocessor();
    Clang->getDiagnosticClient().BeginSourceFile(Clang->getLangOpts(),
                                                 &Clang->getPreprocessor());
    Clang->createASTContext();

    SmallVector<char, 256> serialAST;
    llvm::raw_svector_ostream OS(serialAST);
    llvm::OwningPtr<ASTConsumer> consumer;
    consumer.reset(new PCHGenerator(Clang->getPreprocessor(), "-",
                                    /*IsModule=*/false, /*isysroot=*/"", &OS));
    Clang->getASTContext().setASTMutationListener(
                                            consumer->GetASTMutationListener());
    Clang->setASTConsumer(consumer.take());
    Clang->createSema(TU_Prefix, 0);

    if (firstInclude) {
      Preprocessor &PP = Clang->getPreprocessor();
      PP.getBuiltinInfo().InitializeBuiltins(PP.getIdentifierTable(),
                                             PP.getLangOptions());
    } else {
      assert(!serialBufs.empty());
      SmallVector<llvm::MemoryBuffer *, 4> bufs;
      for (unsigned si = 0, se = serialBufs.size(); si != se; ++si) {
        bufs.push_back(llvm::MemoryBuffer::getMemBufferCopy(
                             StringRef(serialBufs[si]->getBufferStart(),
                                             serialBufs[si]->getBufferSize())));
      }
      std::string pchName = includes[i-1];
      llvm::raw_string_ostream os(pchName);
      os << ".pch" << i-1;
      os.flush();
      
      serialBufNames.push_back(pchName);

      llvm::OwningPtr<ExternalASTSource> Reader;

      Reader.reset(createASTReader(*Clang, pchName, bufs, serialBufNames, 
        Clang->getASTConsumer().GetASTDeserializationListener()));
      if (!Reader)
        return 0;
      Clang->getASTContext().setExternalSource(Reader);
    }
    
    if (!Clang->InitializeSourceManager(includes[i]))
      return 0;

    ParseAST(Clang->getSema());
    OS.flush();
    Clang->getDiagnosticClient().EndSourceFile();
    serialBufs.push_back(
      llvm::MemoryBuffer::getMemBufferCopy(StringRef(serialAST.data(),
                                                           serialAST.size())));
    source->CIs.push_back(Clang.take());
  }

  assert(!serialBufs.empty());
  std::string pchName = includes.back() + ".pch-final";
  serialBufNames.push_back(pchName);
  llvm::OwningPtr<ASTReader> Reader;
  Reader.reset(createASTReader(CI, pchName, serialBufs, serialBufNames));
  if (!Reader)
    return 0;

  source->FinalReader.reset(Reader.take());
  return source.take();
}
Beispiel #20
0
// With -fembed-bitcode, save a copy of the llvm IR as data in the
// __LLVM,__bitcode section.
void clang::EmbedBitcode(llvm::Module *M, const CodeGenOptions &CGOpts,
                         llvm::MemoryBufferRef Buf) {
  if (CGOpts.getEmbedBitcode() == CodeGenOptions::Embed_Off)
    return;

  // Save llvm.compiler.used and remote it.
  SmallVector<Constant*, 2> UsedArray;
  SmallSet<GlobalValue*, 4> UsedGlobals;
  Type *UsedElementType = Type::getInt8Ty(M->getContext())->getPointerTo(0);
  GlobalVariable *Used = collectUsedGlobalVariables(*M, UsedGlobals, true);
  for (auto *GV : UsedGlobals) {
    if (GV->getName() != "llvm.embedded.module" &&
        GV->getName() != "llvm.cmdline")
      UsedArray.push_back(
          ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
  }
  if (Used)
    Used->eraseFromParent();

  // Embed the bitcode for the llvm module.
  std::string Data;
  ArrayRef<uint8_t> ModuleData;
  Triple T(M->getTargetTriple());
  // Create a constant that contains the bitcode.
  // In case of embedding a marker, ignore the input Buf and use the empty
  // ArrayRef. It is also legal to create a bitcode marker even Buf is empty.
  if (CGOpts.getEmbedBitcode() != CodeGenOptions::Embed_Marker) {
    if (!isBitcode((const unsigned char *)Buf.getBufferStart(),
                   (const unsigned char *)Buf.getBufferEnd())) {
      // If the input is LLVM Assembly, bitcode is produced by serializing
      // the module. Use-lists order need to be perserved in this case.
      llvm::raw_string_ostream OS(Data);
      llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
      ModuleData =
          ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
    } else
      // If the input is LLVM bitcode, write the input byte stream directly.
      ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
                                     Buf.getBufferSize());
  }
  llvm::Constant *ModuleConstant =
      llvm::ConstantDataArray::get(M->getContext(), ModuleData);
  llvm::GlobalVariable *GV = new llvm::GlobalVariable(
      *M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
      ModuleConstant);
  GV->setSection(getSectionNameForBitcode(T));
  UsedArray.push_back(
      ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
  if (llvm::GlobalVariable *Old =
          M->getGlobalVariable("llvm.embedded.module", true)) {
    assert(Old->hasOneUse() &&
           "llvm.embedded.module can only be used once in llvm.compiler.used");
    GV->takeName(Old);
    Old->eraseFromParent();
  } else {
    GV->setName("llvm.embedded.module");
  }

  // Skip if only bitcode needs to be embedded.
  if (CGOpts.getEmbedBitcode() != CodeGenOptions::Embed_Bitcode) {
    // Embed command-line options.
    ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CGOpts.CmdArgs.data()),
                              CGOpts.CmdArgs.size());
    llvm::Constant *CmdConstant =
      llvm::ConstantDataArray::get(M->getContext(), CmdData);
    GV = new llvm::GlobalVariable(*M, CmdConstant->getType(), true,
                                  llvm::GlobalValue::PrivateLinkage,
                                  CmdConstant);
    GV->setSection(getSectionNameForCommandline(T));
    UsedArray.push_back(
        ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
    if (llvm::GlobalVariable *Old =
            M->getGlobalVariable("llvm.cmdline", true)) {
      assert(Old->hasOneUse() &&
             "llvm.cmdline can only be used once in llvm.compiler.used");
      GV->takeName(Old);
      Old->eraseFromParent();
    } else {
      GV->setName("llvm.cmdline");
    }
  }

  if (UsedArray.empty())
    return;

  // Recreate llvm.compiler.used.
  ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
  auto *NewUsed = new GlobalVariable(
      *M, ATy, false, llvm::GlobalValue::AppendingLinkage,
      llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
  NewUsed->setSection("llvm.metadata");
}
Beispiel #21
0
/// Emit landing pads and actions.
///
/// The general organization of the table is complex, but the basic concepts are
/// easy.  First there is a header which describes the location and organization
/// of the three components that follow.
///
///  1. The landing pad site information describes the range of code covered by
///     the try.  In our case it's an accumulation of the ranges covered by the
///     invokes in the try.  There is also a reference to the landing pad that
///     handles the exception once processed.  Finally an index into the actions
///     table.
///  2. The action table, in our case, is composed of pairs of type IDs and next
///     action offset.  Starting with the action index from the landing pad
///     site, each type ID is checked for a match to the current exception.  If
///     it matches then the exception and type id are passed on to the landing
///     pad.  Otherwise the next action is looked up.  This chain is terminated
///     with a next action of zero.  If no type id is found then the frame is
///     unwound and handling continues.
///  3. Type ID table contains references to all the C++ typeinfo for all
///     catches in the function.  This tables is reverse indexed base 1.
void EHStreamer::emitExceptionTable() {
  const std::vector<const GlobalValue *> &TypeInfos = MMI->getTypeInfos();
  const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
  const std::vector<LandingPadInfo> &PadInfos = MMI->getLandingPads();

  // Sort the landing pads in order of their type ids.  This is used to fold
  // duplicate actions.
  SmallVector<const LandingPadInfo *, 64> LandingPads;
  LandingPads.reserve(PadInfos.size());

  for (unsigned i = 0, N = PadInfos.size(); i != N; ++i)
    LandingPads.push_back(&PadInfos[i]);

  // Order landing pads lexicographically by type id.
  std::sort(LandingPads.begin(), LandingPads.end(),
            [](const LandingPadInfo *L,
               const LandingPadInfo *R) { return L->TypeIds < R->TypeIds; });

  // Compute the actions table and gather the first action index for each
  // landing pad site.
  SmallVector<ActionEntry, 32> Actions;
  SmallVector<unsigned, 64> FirstActions;
  unsigned SizeActions =
    computeActionsTable(LandingPads, Actions, FirstActions);

  // Invokes and nounwind calls have entries in PadMap (due to being bracketed
  // by try-range labels when lowered).  Ordinary calls do not, so appropriate
  // try-ranges for them need be deduced when using DWARF exception handling.
  RangeMapType PadMap;
  for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
    const LandingPadInfo *LandingPad = LandingPads[i];
    for (unsigned j = 0, E = LandingPad->BeginLabels.size(); j != E; ++j) {
      MCSymbol *BeginLabel = LandingPad->BeginLabels[j];
      assert(!PadMap.count(BeginLabel) && "Duplicate landing pad labels!");
      PadRange P = { i, j };
      PadMap[BeginLabel] = P;
    }
  }

  // Compute the call-site table.
  SmallVector<CallSiteEntry, 64> CallSites;
  computeCallSiteTable(CallSites, PadMap, LandingPads, FirstActions);

  // Final tallies.

  // Call sites.
  bool IsSJLJ = Asm->MAI->getExceptionHandlingType() == ExceptionHandling::SjLj;
  bool HaveTTData = IsSJLJ ? (!TypeInfos.empty() || !FilterIds.empty()) : true;

  unsigned CallSiteTableLength;
  if (IsSJLJ)
    CallSiteTableLength = 0;
  else {
    unsigned SiteStartSize  = 4; // dwarf::DW_EH_PE_udata4
    unsigned SiteLengthSize = 4; // dwarf::DW_EH_PE_udata4
    unsigned LandingPadSize = 4; // dwarf::DW_EH_PE_udata4
    CallSiteTableLength =
      CallSites.size() * (SiteStartSize + SiteLengthSize + LandingPadSize);
  }

  for (unsigned i = 0, e = CallSites.size(); i < e; ++i) {
    CallSiteTableLength += getULEB128Size(CallSites[i].Action);
    if (IsSJLJ)
      CallSiteTableLength += getULEB128Size(i);
  }

  // Type infos.
  const MCSection *LSDASection = Asm->getObjFileLowering().getLSDASection();
  unsigned TTypeEncoding;
  unsigned TypeFormatSize;

  if (!HaveTTData) {
    // For SjLj exceptions, if there is no TypeInfo, then we just explicitly say
    // that we're omitting that bit.
    TTypeEncoding = dwarf::DW_EH_PE_omit;
    // dwarf::DW_EH_PE_absptr
    TypeFormatSize = Asm->getDataLayout().getPointerSize();
  } else {
    // Okay, we have actual filters or typeinfos to emit.  As such, we need to
    // pick a type encoding for them.  We're about to emit a list of pointers to
    // typeinfo objects at the end of the LSDA.  However, unless we're in static
    // mode, this reference will require a relocation by the dynamic linker.
    //
    // Because of this, we have a couple of options:
    //
    //   1) If we are in -static mode, we can always use an absolute reference
    //      from the LSDA, because the static linker will resolve it.
    //
    //   2) Otherwise, if the LSDA section is writable, we can output the direct
    //      reference to the typeinfo and allow the dynamic linker to relocate
    //      it.  Since it is in a writable section, the dynamic linker won't
    //      have a problem.
    //
    //   3) Finally, if we're in PIC mode and the LDSA section isn't writable,
    //      we need to use some form of indirection.  For example, on Darwin,
    //      we can output a statically-relocatable reference to a dyld stub. The
    //      offset to the stub is constant, but the contents are in a section
    //      that is updated by the dynamic linker.  This is easy enough, but we
    //      need to tell the personality function of the unwinder to indirect
    //      through the dyld stub.
    //
    // FIXME: When (3) is actually implemented, we'll have to emit the stubs
    // somewhere.  This predicate should be moved to a shared location that is
    // in target-independent code.
    //
    TTypeEncoding = Asm->getObjFileLowering().getTTypeEncoding();
    TypeFormatSize = Asm->GetSizeOfEncodedValue(TTypeEncoding);
  }

  // Begin the exception table.
  // Sometimes we want not to emit the data into separate section (e.g. ARM
  // EHABI). In this case LSDASection will be NULL.
  if (LSDASection)
    Asm->OutStreamer.SwitchSection(LSDASection);
  Asm->EmitAlignment(2);

  // Emit the LSDA.
  MCSymbol *GCCETSym =
    Asm->OutContext.GetOrCreateSymbol(Twine("GCC_except_table")+
                                      Twine(Asm->getFunctionNumber()));
  Asm->OutStreamer.EmitLabel(GCCETSym);
  Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("exception",
                                                Asm->getFunctionNumber()));

  if (IsSJLJ)
    Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("_LSDA_",
                                                  Asm->getFunctionNumber()));

  // Emit the LSDA header.
  Asm->EmitEncodingByte(dwarf::DW_EH_PE_omit, "@LPStart");
  Asm->EmitEncodingByte(TTypeEncoding, "@TType");

  // The type infos need to be aligned. GCC does this by inserting padding just
  // before the type infos. However, this changes the size of the exception
  // table, so you need to take this into account when you output the exception
  // table size. However, the size is output using a variable length encoding.
  // So by increasing the size by inserting padding, you may increase the number
  // of bytes used for writing the size. If it increases, say by one byte, then
  // you now need to output one less byte of padding to get the type infos
  // aligned. However this decreases the size of the exception table. This
  // changes the value you have to output for the exception table size. Due to
  // the variable length encoding, the number of bytes used for writing the
  // length may decrease. If so, you then have to increase the amount of
  // padding. And so on. If you look carefully at the GCC code you will see that
  // it indeed does this in a loop, going on and on until the values stabilize.
  // We chose another solution: don't output padding inside the table like GCC
  // does, instead output it before the table.
  unsigned SizeTypes = TypeInfos.size() * TypeFormatSize;
  unsigned CallSiteTableLengthSize = getULEB128Size(CallSiteTableLength);
  unsigned TTypeBaseOffset =
    sizeof(int8_t) +                            // Call site format
    CallSiteTableLengthSize +                   // Call site table length size
    CallSiteTableLength +                       // Call site table length
    SizeActions +                               // Actions size
    SizeTypes;
  unsigned TTypeBaseOffsetSize = getULEB128Size(TTypeBaseOffset);
  unsigned TotalSize =
    sizeof(int8_t) +                            // LPStart format
    sizeof(int8_t) +                            // TType format
    (HaveTTData ? TTypeBaseOffsetSize : 0) +    // TType base offset size
    TTypeBaseOffset;                            // TType base offset
  unsigned SizeAlign = (4 - TotalSize) & 3;

  if (HaveTTData) {
    // Account for any extra padding that will be added to the call site table
    // length.
    Asm->EmitULEB128(TTypeBaseOffset, "@TType base offset", SizeAlign);
    SizeAlign = 0;
  }

  bool VerboseAsm = Asm->OutStreamer.isVerboseAsm();

  // SjLj Exception handling
  if (IsSJLJ) {
    Asm->EmitEncodingByte(dwarf::DW_EH_PE_udata4, "Call site");

    // Add extra padding if it wasn't added to the TType base offset.
    Asm->EmitULEB128(CallSiteTableLength, "Call site table length", SizeAlign);

    // Emit the landing pad site information.
    unsigned idx = 0;
    for (SmallVectorImpl<CallSiteEntry>::const_iterator
         I = CallSites.begin(), E = CallSites.end(); I != E; ++I, ++idx) {
      const CallSiteEntry &S = *I;

      // Offset of the landing pad, counted in 16-byte bundles relative to the
      // @LPStart address.
      if (VerboseAsm) {
        Asm->OutStreamer.AddComment(">> Call Site " + Twine(idx) + " <<");
        Asm->OutStreamer.AddComment("  On exception at call site "+Twine(idx));
      }
      Asm->EmitULEB128(idx);

      // Offset of the first associated action record, relative to the start of
      // the action table. This value is biased by 1 (1 indicates the start of
      // the action table), and 0 indicates that there are no actions.
      if (VerboseAsm) {
        if (S.Action == 0)
          Asm->OutStreamer.AddComment("  Action: cleanup");
        else
          Asm->OutStreamer.AddComment("  Action: " +
                                      Twine((S.Action - 1) / 2 + 1));
      }
      Asm->EmitULEB128(S.Action);
    }
  } else {
    // DWARF Exception handling
    assert(Asm->MAI->usesItaniumLSDAForExceptions());

    // The call-site table is a list of all call sites that may throw an
    // exception (including C++ 'throw' statements) in the procedure
    // fragment. It immediately follows the LSDA header. Each entry indicates,
    // for a given call, the first corresponding action record and corresponding
    // landing pad.
    //
    // The table begins with the number of bytes, stored as an LEB128
    // compressed, unsigned integer. The records immediately follow the record
    // count. They are sorted in increasing call-site address. Each record
    // indicates:
    //
    //   * The position of the call-site.
    //   * The position of the landing pad.
    //   * The first action record for that call site.
    //
    // A missing entry in the call-site table indicates that a call is not
    // supposed to throw.

    // Emit the landing pad call site table.
    Asm->EmitEncodingByte(dwarf::DW_EH_PE_udata4, "Call site");

    // Add extra padding if it wasn't added to the TType base offset.
    Asm->EmitULEB128(CallSiteTableLength, "Call site table length", SizeAlign);

    unsigned Entry = 0;
    for (SmallVectorImpl<CallSiteEntry>::const_iterator
         I = CallSites.begin(), E = CallSites.end(); I != E; ++I) {
      const CallSiteEntry &S = *I;

      MCSymbol *EHFuncBeginSym =
        Asm->GetTempSymbol("eh_func_begin", Asm->getFunctionNumber());

      MCSymbol *BeginLabel = S.BeginLabel;
      if (!BeginLabel)
        BeginLabel = EHFuncBeginSym;
      MCSymbol *EndLabel = S.EndLabel;
      if (!EndLabel)
        EndLabel = Asm->GetTempSymbol("eh_func_end", Asm->getFunctionNumber());


      // Offset of the call site relative to the previous call site, counted in
      // number of 16-byte bundles. The first call site is counted relative to
      // the start of the procedure fragment.
      if (VerboseAsm)
        Asm->OutStreamer.AddComment(">> Call Site " + Twine(++Entry) + " <<");
      Asm->EmitLabelDifference(BeginLabel, EHFuncBeginSym, 4);
      if (VerboseAsm)
        Asm->OutStreamer.AddComment(Twine("  Call between ") +
                                    BeginLabel->getName() + " and " +
                                    EndLabel->getName());
      Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);

      // Offset of the landing pad, counted in 16-byte bundles relative to the
      // @LPStart address.
      if (!S.PadLabel) {
        if (VerboseAsm)
          Asm->OutStreamer.AddComment("    has no landing pad");
        Asm->OutStreamer.EmitIntValue(0, 4/*size*/);
      } else {
        if (VerboseAsm)
          Asm->OutStreamer.AddComment(Twine("    jumps to ") +
                                      S.PadLabel->getName());
        Asm->EmitLabelDifference(S.PadLabel, EHFuncBeginSym, 4);
      }

      // Offset of the first associated action record, relative to the start of
      // the action table. This value is biased by 1 (1 indicates the start of
      // the action table), and 0 indicates that there are no actions.
      if (VerboseAsm) {
        if (S.Action == 0)
          Asm->OutStreamer.AddComment("  On action: cleanup");
        else
          Asm->OutStreamer.AddComment("  On action: " +
                                      Twine((S.Action - 1) / 2 + 1));
      }
      Asm->EmitULEB128(S.Action);
    }
  }

  // Emit the Action Table.
  int Entry = 0;
  for (SmallVectorImpl<ActionEntry>::const_iterator
         I = Actions.begin(), E = Actions.end(); I != E; ++I) {
    const ActionEntry &Action = *I;

    if (VerboseAsm) {
      // Emit comments that decode the action table.
      Asm->OutStreamer.AddComment(">> Action Record " + Twine(++Entry) + " <<");
    }

    // Type Filter
    //
    //   Used by the runtime to match the type of the thrown exception to the
    //   type of the catch clauses or the types in the exception specification.
    if (VerboseAsm) {
      if (Action.ValueForTypeID > 0)
        Asm->OutStreamer.AddComment("  Catch TypeInfo " +
                                    Twine(Action.ValueForTypeID));
      else if (Action.ValueForTypeID < 0)
        Asm->OutStreamer.AddComment("  Filter TypeInfo " +
                                    Twine(Action.ValueForTypeID));
      else
        Asm->OutStreamer.AddComment("  Cleanup");
    }
    Asm->EmitSLEB128(Action.ValueForTypeID);

    // Action Record
    //
    //   Self-relative signed displacement in bytes of the next action record,
    //   or 0 if there is no next action record.
    if (VerboseAsm) {
      if (Action.NextAction == 0) {
        Asm->OutStreamer.AddComment("  No further actions");
      } else {
        unsigned NextAction = Entry + (Action.NextAction + 1) / 2;
        Asm->OutStreamer.AddComment("  Continue to action "+Twine(NextAction));
      }
    }
    Asm->EmitSLEB128(Action.NextAction);
  }

  emitTypeInfos(TTypeEncoding);

  Asm->EmitAlignment(2);
}
Beispiel #22
0
/// ParseBlock - Read a block, updating statistics, etc.
static bool ParseBlock(BitstreamCursor &Stream, unsigned BlockID,
                       unsigned IndentLevel) {
  std::string Indent(IndentLevel*2, ' ');
  uint64_t BlockBitStart = Stream.GetCurrentBitNo();

  // Get the statistics for this BlockID.
  PerBlockIDStats &BlockStats = BlockIDStats[BlockID];

  BlockStats.NumInstances++;

  // BLOCKINFO is a special part of the stream.
  if (BlockID == bitc::BLOCKINFO_BLOCK_ID) {
    if (Dump) outs() << Indent << "<BLOCKINFO_BLOCK/>\n";
    if (Stream.ReadBlockInfoBlock())
      return Error("Malformed BlockInfoBlock");
    uint64_t BlockBitEnd = Stream.GetCurrentBitNo();
    BlockStats.NumBits += BlockBitEnd-BlockBitStart;
    return false;
  }

  unsigned NumWords = 0;
  if (Stream.EnterSubBlock(BlockID, &NumWords))
    return Error("Malformed block record");

  const char *BlockName = 0;
  if (Dump) {
    outs() << Indent << "<";
    if ((BlockName = GetBlockName(BlockID, *Stream.getBitStreamReader())))
      outs() << BlockName;
    else
      outs() << "UnknownBlock" << BlockID;

    if (NonSymbolic && BlockName)
      outs() << " BlockID=" << BlockID;

    outs() << " NumWords=" << NumWords
           << " BlockCodeSize=" << Stream.getAbbrevIDWidth() << ">\n";
  }

  SmallVector<uint64_t, 64> Record;

  // Read all the records for this block.
  while (1) {
    if (Stream.AtEndOfStream())
      return Error("Premature end of bitstream");

    uint64_t RecordStartBit = Stream.GetCurrentBitNo();

    BitstreamEntry Entry =
      Stream.advance(BitstreamCursor::AF_DontAutoprocessAbbrevs);
    
    switch (Entry.Kind) {
    case BitstreamEntry::Error:
      return Error("malformed bitcode file");
    case BitstreamEntry::EndBlock: {
      uint64_t BlockBitEnd = Stream.GetCurrentBitNo();
      BlockStats.NumBits += BlockBitEnd-BlockBitStart;
      if (Dump) {
        outs() << Indent << "</";
        if (BlockName)
          outs() << BlockName << ">\n";
        else
          outs() << "UnknownBlock" << BlockID << ">\n";
      }
      return false;
    }
        
    case BitstreamEntry::SubBlock: {
      uint64_t SubBlockBitStart = Stream.GetCurrentBitNo();
      if (ParseBlock(Stream, Entry.ID, IndentLevel+1))
        return true;
      ++BlockStats.NumSubBlocks;
      uint64_t SubBlockBitEnd = Stream.GetCurrentBitNo();
      
      // Don't include subblock sizes in the size of this block.
      BlockBitStart += SubBlockBitEnd-SubBlockBitStart;
      continue;
    }
    case BitstreamEntry::Record:
      // The interesting case.
      break;
    }

    if (Entry.ID == bitc::DEFINE_ABBREV) {
      Stream.ReadAbbrevRecord();
      ++BlockStats.NumAbbrevs;
      continue;
    }
    
    Record.clear();

    ++BlockStats.NumRecords;

    StringRef Blob;
    unsigned Code = Stream.readRecord(Entry.ID, Record, &Blob);

    // Increment the # occurrences of this code.
    if (BlockStats.CodeFreq.size() <= Code)
      BlockStats.CodeFreq.resize(Code+1);
    BlockStats.CodeFreq[Code].NumInstances++;
    BlockStats.CodeFreq[Code].TotalBits +=
      Stream.GetCurrentBitNo()-RecordStartBit;
    if (Entry.ID != bitc::UNABBREV_RECORD) {
      BlockStats.CodeFreq[Code].NumAbbrev++;
      ++BlockStats.NumAbbreviatedRecords;
    }

    if (Dump) {
      outs() << Indent << "  <";
      if (const char *CodeName =
            GetCodeName(Code, BlockID, *Stream.getBitStreamReader()))
        outs() << CodeName;
      else
        outs() << "UnknownCode" << Code;
      if (NonSymbolic &&
          GetCodeName(Code, BlockID, *Stream.getBitStreamReader()))
        outs() << " codeid=" << Code;
      if (Entry.ID != bitc::UNABBREV_RECORD)
        outs() << " abbrevid=" << Entry.ID;

      for (unsigned i = 0, e = Record.size(); i != e; ++i)
        outs() << " op" << i << "=" << (int64_t)Record[i];

      outs() << "/>";

      if (Blob.data()) {
        outs() << " blob data = ";
        bool BlobIsPrintable = true;
        for (unsigned i = 0, e = Blob.size(); i != e; ++i)
          if (!isprint(static_cast<unsigned char>(Blob[i]))) {
            BlobIsPrintable = false;
            break;
          }

        if (BlobIsPrintable)
          outs() << "'" << Blob << "'";
        else
          outs() << "unprintable, " << Blob.size() << " bytes.";
      }

      outs() << "\n";
    }
  }
}
Beispiel #23
0
SDValue
BlackfinTargetLowering::LowerCall(SDValue Chain, SDValue Callee,
                                  CallingConv::ID CallConv, bool isVarArg,
                                  bool &isTailCall,
                                  const SmallVectorImpl<ISD::OutputArg> &Outs,
                                  const SmallVectorImpl<SDValue> &OutVals,
                                  const SmallVectorImpl<ISD::InputArg> &Ins,
                                  DebugLoc dl, SelectionDAG &DAG,
                                  SmallVectorImpl<SDValue> &InVals) const {
  // Blackfin target does not yet support tail call optimization.
  isTailCall = false;

  // Analyze operands of the call, assigning locations to each operand.
  SmallVector<CCValAssign, 16> ArgLocs;
  CCState CCInfo(CallConv, isVarArg, DAG.getMachineFunction(),
		 DAG.getTarget(), ArgLocs, *DAG.getContext());
  CCInfo.AllocateStack(12, 4);  // ABI requires 12 bytes stack space
  CCInfo.AnalyzeCallOperands(Outs, CC_Blackfin);

  // Get the size of the outgoing arguments stack space requirement.
  unsigned ArgsSize = CCInfo.getNextStackOffset();

  Chain = DAG.getCALLSEQ_START(Chain, DAG.getIntPtrConstant(ArgsSize, true));
  SmallVector<std::pair<unsigned, SDValue>, 8> RegsToPass;
  SmallVector<SDValue, 8> MemOpChains;

  // Walk the register/memloc assignments, inserting copies/loads.
  for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
    CCValAssign &VA = ArgLocs[i];
    SDValue Arg = OutVals[i];

    // Promote the value if needed.
    switch (VA.getLocInfo()) {
    default: llvm_unreachable("Unknown loc info!");
    case CCValAssign::Full: break;
    case CCValAssign::SExt:
      Arg = DAG.getNode(ISD::SIGN_EXTEND, dl, VA.getLocVT(), Arg);
      break;
    case CCValAssign::ZExt:
      Arg = DAG.getNode(ISD::ZERO_EXTEND, dl, VA.getLocVT(), Arg);
      break;
    case CCValAssign::AExt:
      Arg = DAG.getNode(ISD::ANY_EXTEND, dl, VA.getLocVT(), Arg);
      break;
    }

    // Arguments that can be passed on register must be kept at
    // RegsToPass vector
    if (VA.isRegLoc()) {
      RegsToPass.push_back(std::make_pair(VA.getLocReg(), Arg));
    } else {
      assert(VA.isMemLoc() && "CCValAssign must be RegLoc or MemLoc");
      int Offset = VA.getLocMemOffset();
      assert(Offset%4 == 0 && "Unaligned LocMemOffset");
      assert(VA.getLocVT()==MVT::i32 && "Illegal CCValAssign type");
      SDValue SPN = DAG.getCopyFromReg(Chain, dl, BF::SP, MVT::i32);
      SDValue OffsetN = DAG.getIntPtrConstant(Offset);
      OffsetN = DAG.getNode(ISD::ADD, dl, MVT::i32, SPN, OffsetN);
      MemOpChains.push_back(DAG.getStore(Chain, dl, Arg, OffsetN,
                                         MachinePointerInfo(),false, false, 0));
    }
  }

  // Transform all store nodes into one single node because
  // all store nodes are independent of each other.
  if (!MemOpChains.empty())
    Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other,
                        &MemOpChains[0], MemOpChains.size());

  // Build a sequence of copy-to-reg nodes chained together with token
  // chain and flag operands which copy the outgoing args into registers.
  // The InFlag in necessary since all emitted instructions must be
  // stuck together.
  SDValue InFlag;
  for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i) {
    Chain = DAG.getCopyToReg(Chain, dl, RegsToPass[i].first,
                             RegsToPass[i].second, InFlag);
    InFlag = Chain.getValue(1);
  }

  // If the callee is a GlobalAddress node (quite common, every direct call is)
  // turn it into a TargetGlobalAddress node so that legalize doesn't hack it.
  // Likewise ExternalSymbol -> TargetExternalSymbol.
  if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee))
    Callee = DAG.getTargetGlobalAddress(G->getGlobal(), dl, MVT::i32);
  else if (ExternalSymbolSDNode *E = dyn_cast<ExternalSymbolSDNode>(Callee))
    Callee = DAG.getTargetExternalSymbol(E->getSymbol(), MVT::i32);

  std::vector<EVT> NodeTys;
  NodeTys.push_back(MVT::Other);   // Returns a chain
  NodeTys.push_back(MVT::Glue);    // Returns a flag for retval copy to use.
  SDValue Ops[] = { Chain, Callee, InFlag };
  Chain = DAG.getNode(BFISD::CALL, dl, NodeTys, Ops,
                      InFlag.getNode() ? 3 : 2);
  InFlag = Chain.getValue(1);

  Chain = DAG.getCALLSEQ_END(Chain, DAG.getIntPtrConstant(ArgsSize, true),
                             DAG.getIntPtrConstant(0, true), InFlag);
  InFlag = Chain.getValue(1);

  // Assign locations to each value returned by this call.
  SmallVector<CCValAssign, 16> RVLocs;
  CCState RVInfo(CallConv, isVarArg, DAG.getMachineFunction(),
		 DAG.getTarget(), RVLocs, *DAG.getContext());

  RVInfo.AnalyzeCallResult(Ins, RetCC_Blackfin);

  // Copy all of the result registers out of their specified physreg.
  for (unsigned i = 0; i != RVLocs.size(); ++i) {
    CCValAssign &RV = RVLocs[i];
    unsigned Reg = RV.getLocReg();

    Chain = DAG.getCopyFromReg(Chain, dl, Reg,
                               RVLocs[i].getLocVT(), InFlag);
    SDValue Val = Chain.getValue(0);
    InFlag = Chain.getValue(2);
    Chain = Chain.getValue(1);

    // Callee is responsible for extending any i16 return values.
    switch (RV.getLocInfo()) {
    case CCValAssign::SExt:
      Val = DAG.getNode(ISD::AssertSext, dl, RV.getLocVT(), Val,
                        DAG.getValueType(RV.getValVT()));
      break;
    case CCValAssign::ZExt:
      Val = DAG.getNode(ISD::AssertZext, dl, RV.getLocVT(), Val,
                        DAG.getValueType(RV.getValVT()));
      break;
    default:
      break;
    }

    // Truncate to valtype
    if (RV.getLocInfo() != CCValAssign::Full)
      Val = DAG.getNode(ISD::TRUNCATE, dl, RV.getValVT(), Val);
    InVals.push_back(Val);
  }

  return Chain;
}
Beispiel #24
0
TargetMachine *EmitAssemblyHelper::CreateTargetMachine(bool MustCreateTM) {
  // Create the TargetMachine for generating code.
  std::string Error;
  std::string Triple = TheModule->getTargetTriple();
  const llvm::Target *TheTarget = TargetRegistry::lookupTarget(Triple, Error);
  if (!TheTarget) {
    if (MustCreateTM)
      Diags.Report(diag::err_fe_unable_to_create_target) << Error;
    return 0;
  }

  // FIXME: Expose these capabilities via actual APIs!!!! Aside from just
  // being gross, this is also totally broken if we ever care about
  // concurrency.

  //TargetMachine::setAsmVerbosityDefault(CodeGenOpts.AsmVerbose);

  //TargetMachine::setFunctionSections(CodeGenOpts.FunctionSections);
  //TargetMachine::setDataSections    (CodeGenOpts.DataSections);

  // FIXME: Parse this earlier.
  llvm::CodeModel::Model CM;
  if (CodeGenOpts.CodeModel == "small") {
    CM = llvm::CodeModel::Small;
  } else if (CodeGenOpts.CodeModel == "kernel") {
    CM = llvm::CodeModel::Kernel;
  } else if (CodeGenOpts.CodeModel == "medium") {
    CM = llvm::CodeModel::Medium;
  } else if (CodeGenOpts.CodeModel == "large") {
    CM = llvm::CodeModel::Large;
  } else {
    assert(CodeGenOpts.CodeModel.empty() && "Invalid code model!");
    CM = llvm::CodeModel::Default;
  }

  SmallVector<const char *, 16> BackendArgs;
  BackendArgs.push_back("clang"); // Fake program name.
  if (!CodeGenOpts.DebugPass.empty()) {
    BackendArgs.push_back("-debug-pass");
    BackendArgs.push_back(CodeGenOpts.DebugPass.c_str());
  }
  if (!CodeGenOpts.LimitFloatPrecision.empty()) {
    BackendArgs.push_back("-limit-float-precision");
    BackendArgs.push_back(CodeGenOpts.LimitFloatPrecision.c_str());
  }
  if (llvm::TimePassesIsEnabled)
    BackendArgs.push_back("-time-passes");
  for (unsigned i = 0, e = CodeGenOpts.BackendOptions.size(); i != e; ++i)
    BackendArgs.push_back(CodeGenOpts.BackendOptions[i].c_str());
  if (CodeGenOpts.NoGlobalMerge)
    BackendArgs.push_back("-global-merge=false");
  BackendArgs.push_back(0);
  llvm::cl::ParseCommandLineOptions(BackendArgs.size() - 1,
                                    BackendArgs.data());

  std::string FeaturesStr;
  if (TargetOpts.Features.size()) {
    SubtargetFeatures Features;
    for (std::vector<std::string>::const_iterator
           it = TargetOpts.Features.begin(),
           ie = TargetOpts.Features.end(); it != ie; ++it)
      Features.AddFeature(*it);
    FeaturesStr = Features.getString();
  }

  llvm::Reloc::Model RM = llvm::Reloc::Default;
  if (CodeGenOpts.RelocationModel == "static") {
    RM = llvm::Reloc::Static;
  } else if (CodeGenOpts.RelocationModel == "pic") {
    RM = llvm::Reloc::PIC_;
  } else {
    assert(CodeGenOpts.RelocationModel == "dynamic-no-pic" &&
           "Invalid PIC model!");
    RM = llvm::Reloc::DynamicNoPIC;
  }

  CodeGenOpt::Level OptLevel = CodeGenOpt::Default;
  switch (CodeGenOpts.OptimizationLevel) {
  default: break;
  case 0: OptLevel = CodeGenOpt::None; break;
  case 3: OptLevel = CodeGenOpt::Aggressive; break;
  }

  llvm::TargetOptions Options;

  // Set frame pointer elimination mode.
  // WARNING: This code is now dead for LLVM trunk checkin r238244
  // The checkin in question removes the global variable NoFramePointerElim 
  // from TargetOptions in favor of using resetTargetOptions.  This function
  // resides in TargetMachine and called for individual function instances
  // via the DAG selection. 
#if 0
  if (!CodeGenOpts.DisableFPElim) {
    Options.NoFramePointerElim = false;
    //Options.NoFramePointerElimNonLeaf = false;
  } else if (CodeGenOpts.OmitLeafFramePointer) {
    Options.NoFramePointerElim = false;
    //Options.NoFramePointerElimNonLeaf = true;
  } else {
    Options.NoFramePointerElim = true;
    //Options.NoFramePointerElimNonLeaf = true;
  }
#endif

  if (CodeGenOpts.UseInitArray)
    Options.UseInitArray = true;

  // Set float ABI type.
  if (CodeGenOpts.FloatABI == "soft" || CodeGenOpts.FloatABI == "softfp")
    Options.FloatABIType = llvm::FloatABI::Soft;
  else if (CodeGenOpts.FloatABI == "hard")
    Options.FloatABIType = llvm::FloatABI::Hard;
  else {
    assert(CodeGenOpts.FloatABI.empty() && "Invalid float abi!");
    Options.FloatABIType = llvm::FloatABI::Default;
  }

  // Set FP fusion mode.
  switch (CodeGenOpts.getFPContractMode()) {
  case CodeGenOptions::FPC_Off:
    Options.AllowFPOpFusion = llvm::FPOpFusion::Strict;
    break;
  case CodeGenOptions::FPC_On:
    Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
    break;
  case CodeGenOptions::FPC_Fast:
    Options.AllowFPOpFusion = llvm::FPOpFusion::Fast;
    break;
  }

  Options.LessPreciseFPMADOption = CodeGenOpts.LessPreciseFPMAD;
  Options.NoInfsFPMath = CodeGenOpts.NoInfsFPMath;
  Options.NoNaNsFPMath = CodeGenOpts.NoNaNsFPMath;
  Options.NoZerosInBSS = CodeGenOpts.NoZeroInitializedInBSS;
  Options.UnsafeFPMath = CodeGenOpts.UnsafeFPMath;
  //TODO : This definition has moved to Module code rather thn TargetOptions
  //       This is true from LLVM trunk r237079 and beyond
  //Options.UseSoftFloat = CodeGenOpts.SoftFloat; 
  Options.StackAlignmentOverride = CodeGenOpts.StackAlignment;
  //Options.RealignStack = CodeGenOpts.StackRealignment;
  //Options.DisableTailCalls = CodeGenOpts.DisableTailCalls;
  //Options.TrapFuncName = CodeGenOpts.TrapFuncName;
  //Options.PositionIndependentExecutable = LangOpts.PIELevel != 0;
  //Options.EnableSegmentedStacks = CodeGenOpts.EnableSegmentedStacks;

  TargetMachine *TM = TheTarget->createTargetMachine(Triple, TargetOpts.CPU,
                                                     FeaturesStr, Options,
                                                     RM, CM, OptLevel);

  //if (CodeGenOpts.RelaxAll)
  //  TM->setMCRelaxAll(true);
  //if (CodeGenOpts.SaveTempLabels)
  //  TM->setMCSaveTempLabels(true);
  //if (CodeGenOpts.NoDwarf2CFIAsm)
  //  TM->setMCUseCFI(false);
  //if (!CodeGenOpts.NoDwarfDirectoryAsm)
  //  TM->setMCUseDwarfDirectory(true);
  //if (CodeGenOpts.NoExecStack)
  //  TM->setMCNoExecStack(true);

  return TM;
}
Beispiel #25
0
/// EmitSchedule - Emit the machine code in scheduled order. Return the new
/// InsertPos and MachineBasicBlock that contains this insertion
/// point. ScheduleDAGSDNodes holds a BB pointer for convenience, but this does
/// not necessarily refer to returned BB. The emitter may split blocks.
MachineBasicBlock *ScheduleDAGSDNodes::
EmitSchedule(MachineBasicBlock::iterator &InsertPos) {
  InstrEmitter Emitter(BB, InsertPos);
  DenseMap<SDValue, unsigned> VRBaseMap;
  DenseMap<SUnit*, unsigned> CopyVRBaseMap;
  SmallVector<std::pair<unsigned, MachineInstr*>, 32> Orders;
  SmallSet<unsigned, 8> Seen;
  bool HasDbg = DAG->hasDebugValues();

  // If this is the first BB, emit byval parameter dbg_value's.
  if (HasDbg && BB->getParent()->begin() == MachineFunction::iterator(BB)) {
    SDDbgInfo::DbgIterator PDI = DAG->ByvalParmDbgBegin();
    SDDbgInfo::DbgIterator PDE = DAG->ByvalParmDbgEnd();
    for (; PDI != PDE; ++PDI) {
      MachineInstr *DbgMI= Emitter.EmitDbgValue(*PDI, VRBaseMap);
      if (DbgMI)
        BB->insert(InsertPos, DbgMI);
    }
  }

  for (unsigned i = 0, e = Sequence.size(); i != e; i++) {
    SUnit *SU = Sequence[i];
    if (!SU) {
      // Null SUnit* is a noop.
      TII->insertNoop(*Emitter.getBlock(), InsertPos);
      continue;
    }

    // For pre-regalloc scheduling, create instructions corresponding to the
    // SDNode and any glued SDNodes and append them to the block.
    if (!SU->getNode()) {
      // Emit a copy.
      EmitPhysRegCopy(SU, CopyVRBaseMap, InsertPos);
      continue;
    }

    SmallVector<SDNode *, 4> GluedNodes;
    for (SDNode *N = SU->getNode()->getGluedNode(); N; N = N->getGluedNode())
      GluedNodes.push_back(N);
    while (!GluedNodes.empty()) {
      SDNode *N = GluedNodes.back();
      Emitter.EmitNode(GluedNodes.back(), SU->OrigNode != SU, SU->isCloned,
                       VRBaseMap);
      // Remember the source order of the inserted instruction.
      if (HasDbg)
        ProcessSourceNode(N, DAG, Emitter, VRBaseMap, Orders, Seen);
      GluedNodes.pop_back();
    }
    Emitter.EmitNode(SU->getNode(), SU->OrigNode != SU, SU->isCloned,
                     VRBaseMap);
    // Remember the source order of the inserted instruction.
    if (HasDbg)
      ProcessSourceNode(SU->getNode(), DAG, Emitter, VRBaseMap, Orders,
                        Seen);
  }

  // Insert all the dbg_values which have not already been inserted in source
  // order sequence.
  if (HasDbg) {
    MachineBasicBlock::iterator BBBegin = BB->getFirstNonPHI();

    // Sort the source order instructions and use the order to insert debug
    // values.
    std::sort(Orders.begin(), Orders.end(), less_first());

    SDDbgInfo::DbgIterator DI = DAG->DbgBegin();
    SDDbgInfo::DbgIterator DE = DAG->DbgEnd();
    // Now emit the rest according to source order.
    unsigned LastOrder = 0;
    for (unsigned i = 0, e = Orders.size(); i != e && DI != DE; ++i) {
      unsigned Order = Orders[i].first;
      MachineInstr *MI = Orders[i].second;
      // Insert all SDDbgValue's whose order(s) are before "Order".
      if (!MI)
        continue;
      for (; DI != DE &&
             (*DI)->getOrder() >= LastOrder && (*DI)->getOrder() < Order; ++DI) {
        if ((*DI)->isInvalidated())
          continue;
        MachineInstr *DbgMI = Emitter.EmitDbgValue(*DI, VRBaseMap);
        if (DbgMI) {
          if (!LastOrder)
            // Insert to start of the BB (after PHIs).
            BB->insert(BBBegin, DbgMI);
          else {
            // Insert at the instruction, which may be in a different
            // block, if the block was split by a custom inserter.
            MachineBasicBlock::iterator Pos = MI;
            MI->getParent()->insert(Pos, DbgMI);
          }
        }
      }
      LastOrder = Order;
    }
    // Add trailing DbgValue's before the terminator. FIXME: May want to add
    // some of them before one or more conditional branches?
    SmallVector<MachineInstr*, 8> DbgMIs;
    while (DI != DE) {
      if (!(*DI)->isInvalidated())
        if (MachineInstr *DbgMI = Emitter.EmitDbgValue(*DI, VRBaseMap))
          DbgMIs.push_back(DbgMI);
      ++DI;
    }

    MachineBasicBlock *InsertBB = Emitter.getBlock();
    MachineBasicBlock::iterator Pos = InsertBB->getFirstTerminator();
    InsertBB->insert(Pos, DbgMIs.begin(), DbgMIs.end());
  }

  InsertPos = Emitter.getInsertPos();
  return Emitter.getBlock();
}
Beispiel #26
0
/// ComputePHILiveOutRegInfo - Compute LiveOutInfo for a PHI's destination
/// register based on the LiveOutInfo of its operands.
void FunctionLoweringInfo::ComputePHILiveOutRegInfo(const PHINode *PN) {
  Type *Ty = PN->getType();
  if (!Ty->isIntegerTy() || Ty->isVectorTy())
    return;

  const TargetLowering *TLI = TM.getSubtargetImpl()->getTargetLowering();

  SmallVector<EVT, 1> ValueVTs;
  ComputeValueVTs(*TLI, Ty, ValueVTs);
  assert(ValueVTs.size() == 1 &&
         "PHIs with non-vector integer types should have a single VT.");
  EVT IntVT = ValueVTs[0];

  if (TLI->getNumRegisters(PN->getContext(), IntVT) != 1)
    return;
  IntVT = TLI->getTypeToTransformTo(PN->getContext(), IntVT);
  unsigned BitWidth = IntVT.getSizeInBits();

  unsigned DestReg = ValueMap[PN];
  if (!TargetRegisterInfo::isVirtualRegister(DestReg))
    return;
  LiveOutRegInfo.grow(DestReg);
  LiveOutInfo &DestLOI = LiveOutRegInfo[DestReg];

  Value *V = PN->getIncomingValue(0);
  if (isa<UndefValue>(V) || isa<ConstantExpr>(V)) {
    DestLOI.NumSignBits = 1;
    APInt Zero(BitWidth, 0);
    DestLOI.KnownZero = Zero;
    DestLOI.KnownOne = Zero;
    return;
  }

  if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
    APInt Val = CI->getValue().zextOrTrunc(BitWidth);
    DestLOI.NumSignBits = Val.getNumSignBits();
    DestLOI.KnownZero = ~Val;
    DestLOI.KnownOne = Val;
  } else {
    assert(ValueMap.count(V) && "V should have been placed in ValueMap when its"
                                "CopyToReg node was created.");
    unsigned SrcReg = ValueMap[V];
    if (!TargetRegisterInfo::isVirtualRegister(SrcReg)) {
      DestLOI.IsValid = false;
      return;
    }
    const LiveOutInfo *SrcLOI = GetLiveOutRegInfo(SrcReg, BitWidth);
    if (!SrcLOI) {
      DestLOI.IsValid = false;
      return;
    }
    DestLOI = *SrcLOI;
  }

  assert(DestLOI.KnownZero.getBitWidth() == BitWidth &&
         DestLOI.KnownOne.getBitWidth() == BitWidth &&
         "Masks should have the same bit width as the type.");

  for (unsigned i = 1, e = PN->getNumIncomingValues(); i != e; ++i) {
    Value *V = PN->getIncomingValue(i);
    if (isa<UndefValue>(V) || isa<ConstantExpr>(V)) {
      DestLOI.NumSignBits = 1;
      APInt Zero(BitWidth, 0);
      DestLOI.KnownZero = Zero;
      DestLOI.KnownOne = Zero;
      return;
    }

    if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
      APInt Val = CI->getValue().zextOrTrunc(BitWidth);
      DestLOI.NumSignBits = std::min(DestLOI.NumSignBits, Val.getNumSignBits());
      DestLOI.KnownZero &= ~Val;
      DestLOI.KnownOne &= Val;
      continue;
    }

    assert(ValueMap.count(V) && "V should have been placed in ValueMap when "
                                "its CopyToReg node was created.");
    unsigned SrcReg = ValueMap[V];
    if (!TargetRegisterInfo::isVirtualRegister(SrcReg)) {
      DestLOI.IsValid = false;
      return;
    }
    const LiveOutInfo *SrcLOI = GetLiveOutRegInfo(SrcReg, BitWidth);
    if (!SrcLOI) {
      DestLOI.IsValid = false;
      return;
    }
    DestLOI.NumSignBits = std::min(DestLOI.NumSignBits, SrcLOI->NumSignBits);
    DestLOI.KnownZero &= SrcLOI->KnownZero;
    DestLOI.KnownOne &= SrcLOI->KnownOne;
  }
}
Beispiel #27
0
/// sink - When an instruction is found to only be used outside of the loop,
/// this function moves it to the exit blocks and patches up SSA form as needed.
/// This method is guaranteed to remove the original instruction from its
/// position, and may either delete it or move it to outside of the loop.
///
void LICM::sink(Instruction &I) {
  DEBUG(dbgs() << "LICM sinking instruction: " << I << "\n");

  SmallVector<BasicBlock*, 8> ExitBlocks;
  CurLoop->getUniqueExitBlocks(ExitBlocks);

  if (isa<LoadInst>(I)) ++NumMovedLoads;
  else if (isa<CallInst>(I)) ++NumMovedCalls;
  ++NumSunk;
  Changed = true;

  // The case where there is only a single exit node of this loop is common
  // enough that we handle it as a special (more efficient) case.  It is more
  // efficient to handle because there are no PHI nodes that need to be placed.
  if (ExitBlocks.size() == 1) {
    if (!DT->dominates(I.getParent(), ExitBlocks[0])) {
      // Instruction is not used, just delete it.
      CurAST->deleteValue(&I);
      // If I has users in unreachable blocks, eliminate.
      // If I is not void type then replaceAllUsesWith undef.
      // This allows ValueHandlers and custom metadata to adjust itself.
      if (!I.use_empty())
        I.replaceAllUsesWith(UndefValue::get(I.getType()));
      I.eraseFromParent();
    } else {
      // Move the instruction to the start of the exit block, after any PHI
      // nodes in it.
      I.moveBefore(ExitBlocks[0]->getFirstInsertionPt());

      // This instruction is no longer in the AST for the current loop, because
      // we just sunk it out of the loop.  If we just sunk it into an outer
      // loop, we will rediscover the operation when we process it.
      CurAST->deleteValue(&I);
    }
    return;
  }

  if (ExitBlocks.empty()) {
    // The instruction is actually dead if there ARE NO exit blocks.
    CurAST->deleteValue(&I);
    // If I has users in unreachable blocks, eliminate.
    // If I is not void type then replaceAllUsesWith undef.
    // This allows ValueHandlers and custom metadata to adjust itself.
    if (!I.use_empty())
      I.replaceAllUsesWith(UndefValue::get(I.getType()));
    I.eraseFromParent();
    return;
  }

  // Otherwise, if we have multiple exits, use the SSAUpdater to do all of the
  // hard work of inserting PHI nodes as necessary.
  SmallVector<PHINode*, 8> NewPHIs;
  SSAUpdater SSA(&NewPHIs);

  if (!I.use_empty())
    SSA.Initialize(I.getType(), I.getName());

  // Insert a copy of the instruction in each exit block of the loop that is
  // dominated by the instruction.  Each exit block is known to only be in the
  // ExitBlocks list once.
  BasicBlock *InstOrigBB = I.getParent();
  unsigned NumInserted = 0;

  for (unsigned i = 0, e = ExitBlocks.size(); i != e; ++i) {
    BasicBlock *ExitBlock = ExitBlocks[i];

    if (!DT->dominates(InstOrigBB, ExitBlock))
      continue;

    // Insert the code after the last PHI node.
    BasicBlock::iterator InsertPt = ExitBlock->getFirstInsertionPt();

    // If this is the first exit block processed, just move the original
    // instruction, otherwise clone the original instruction and insert
    // the copy.
    Instruction *New;
    if (NumInserted++ == 0) {
      I.moveBefore(InsertPt);
      New = &I;
    } else {
      New = I.clone();
      if (!I.getName().empty())
        New->setName(I.getName()+".le");
      ExitBlock->getInstList().insert(InsertPt, New);
    }

    // Now that we have inserted the instruction, inform SSAUpdater.
    if (!I.use_empty())
      SSA.AddAvailableValue(ExitBlock, New);
  }

  // If the instruction doesn't dominate any exit blocks, it must be dead.
  if (NumInserted == 0) {
    CurAST->deleteValue(&I);
    if (!I.use_empty())
      I.replaceAllUsesWith(UndefValue::get(I.getType()));
    I.eraseFromParent();
    return;
  }

  // Next, rewrite uses of the instruction, inserting PHI nodes as needed.
  for (Value::use_iterator UI = I.use_begin(), UE = I.use_end(); UI != UE; ) {
    // Grab the use before incrementing the iterator.
    Use &U = UI.getUse();
    // Increment the iterator before removing the use from the list.
    ++UI;
    SSA.RewriteUseAfterInsertions(U);
  }

  // Update CurAST for NewPHIs if I had pointer type.
  if (I.getType()->isPointerTy())
    for (unsigned i = 0, e = NewPHIs.size(); i != e; ++i)
      CurAST->copyValue(&I, NewPHIs[i]);

  // Finally, remove the instruction from CurAST.  It is no longer in the loop.
  CurAST->deleteValue(&I);
}
Beispiel #28
0
void FunctionLoweringInfo::set(const Function &fn, MachineFunction &mf,
                               SelectionDAG *DAG) {
  const TargetLowering *TLI = TM.getSubtargetImpl()->getTargetLowering();

  Fn = &fn;
  MF = &mf;
  RegInfo = &MF->getRegInfo();

  // Check whether the function can return without sret-demotion.
  SmallVector<ISD::OutputArg, 4> Outs;
  GetReturnInfo(Fn->getReturnType(), Fn->getAttributes(), Outs, *TLI);
  CanLowerReturn = TLI->CanLowerReturn(Fn->getCallingConv(), *MF,
                                       Fn->isVarArg(),
                                       Outs, Fn->getContext());

  // Initialize the mapping of values to registers.  This is only set up for
  // instruction values that are used outside of the block that defines
  // them.
  Function::const_iterator BB = Fn->begin(), EB = Fn->end();
  for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I != E; ++I)
    if (const AllocaInst *AI = dyn_cast<AllocaInst>(I)) {
      // Don't fold inalloca allocas or other dynamic allocas into the initial
      // stack frame allocation, even if they are in the entry block.
      if (!AI->isStaticAlloca())
        continue;

      if (const ConstantInt *CUI = dyn_cast<ConstantInt>(AI->getArraySize())) {
        Type *Ty = AI->getAllocatedType();
        uint64_t TySize = TLI->getDataLayout()->getTypeAllocSize(Ty);
        unsigned Align =
          std::max((unsigned)TLI->getDataLayout()->getPrefTypeAlignment(Ty),
                   AI->getAlignment());

        TySize *= CUI->getZExtValue();   // Get total allocated size.
        if (TySize == 0) TySize = 1; // Don't create zero-sized stack objects.

        StaticAllocaMap[AI] =
          MF->getFrameInfo()->CreateStackObject(TySize, Align, false, AI);
      }
    }

  for (; BB != EB; ++BB)
    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
         I != E; ++I) {
      // Look for dynamic allocas.
      if (const AllocaInst *AI = dyn_cast<AllocaInst>(I)) {
        if (!AI->isStaticAlloca()) {
          unsigned Align = std::max(
              (unsigned)TLI->getDataLayout()->getPrefTypeAlignment(
                AI->getAllocatedType()),
              AI->getAlignment());
          unsigned StackAlign =
              TM.getSubtargetImpl()->getFrameLowering()->getStackAlignment();
          if (Align <= StackAlign)
            Align = 0;
          // Inform the Frame Information that we have variable-sized objects.
          MF->getFrameInfo()->CreateVariableSizedObject(Align ? Align : 1, AI);
        }
      }

      // Look for inline asm that clobbers the SP register.
      if (isa<CallInst>(I) || isa<InvokeInst>(I)) {
        ImmutableCallSite CS(I);
        if (isa<InlineAsm>(CS.getCalledValue())) {
          unsigned SP = TLI->getStackPointerRegisterToSaveRestore();
          std::vector<TargetLowering::AsmOperandInfo> Ops =
            TLI->ParseConstraints(CS);
          for (size_t I = 0, E = Ops.size(); I != E; ++I) {
            TargetLowering::AsmOperandInfo &Op = Ops[I];
            if (Op.Type == InlineAsm::isClobber) {
              // Clobbers don't have SDValue operands, hence SDValue().
              TLI->ComputeConstraintToUse(Op, SDValue(), DAG);
              std::pair<unsigned, const TargetRegisterClass*> PhysReg =
                TLI->getRegForInlineAsmConstraint(Op.ConstraintCode,
                                                  Op.ConstraintVT);
              if (PhysReg.first == SP)
                MF->getFrameInfo()->setHasInlineAsmWithSPAdjust(true);
            }
          }
        }
      }

      // Mark values used outside their block as exported, by allocating
      // a virtual register for them.
      if (isUsedOutsideOfDefiningBlock(I))
        if (!isa<AllocaInst>(I) ||
            !StaticAllocaMap.count(cast<AllocaInst>(I)))
          InitializeRegForValue(I);

      // Collect llvm.dbg.declare information. This is done now instead of
      // during the initial isel pass through the IR so that it is done
      // in a predictable order.
      if (const DbgDeclareInst *DI = dyn_cast<DbgDeclareInst>(I)) {
        MachineModuleInfo &MMI = MF->getMMI();
        DIVariable DIVar(DI->getVariable());
        assert((!DIVar || DIVar.isVariable()) &&
          "Variable in DbgDeclareInst should be either null or a DIVariable.");
        if (MMI.hasDebugInfo() &&
            DIVar &&
            !DI->getDebugLoc().isUnknown()) {
          // Don't handle byval struct arguments or VLAs, for example.
          // Non-byval arguments are handled here (they refer to the stack
          // temporary alloca at this point).
          const Value *Address = DI->getAddress();
          if (Address) {
            if (const BitCastInst *BCI = dyn_cast<BitCastInst>(Address))
              Address = BCI->getOperand(0);
            if (const AllocaInst *AI = dyn_cast<AllocaInst>(Address)) {
              DenseMap<const AllocaInst *, int>::iterator SI =
                StaticAllocaMap.find(AI);
              if (SI != StaticAllocaMap.end()) { // Check for VLAs.
                int FI = SI->second;
                MMI.setVariableDbgInfo(DI->getVariable(),
                                       FI, DI->getDebugLoc());
              }
            }
          }
        }
      }
    }

  // Create an initial MachineBasicBlock for each LLVM BasicBlock in F.  This
  // also creates the initial PHI MachineInstrs, though none of the input
  // operands are populated.
  for (BB = Fn->begin(); BB != EB; ++BB) {
    MachineBasicBlock *MBB = mf.CreateMachineBasicBlock(BB);
    MBBMap[BB] = MBB;
    MF->push_back(MBB);

    // Transfer the address-taken flag. This is necessary because there could
    // be multiple MachineBasicBlocks corresponding to one BasicBlock, and only
    // the first one should be marked.
    if (BB->hasAddressTaken())
      MBB->setHasAddressTaken();

    // Create Machine PHI nodes for LLVM PHI nodes, lowering them as
    // appropriate.
    for (BasicBlock::const_iterator I = BB->begin();
         const PHINode *PN = dyn_cast<PHINode>(I); ++I) {
      if (PN->use_empty()) continue;

      // Skip empty types
      if (PN->getType()->isEmptyTy())
        continue;

      DebugLoc DL = PN->getDebugLoc();
      unsigned PHIReg = ValueMap[PN];
      assert(PHIReg && "PHI node does not have an assigned virtual register!");

      SmallVector<EVT, 4> ValueVTs;
      ComputeValueVTs(*TLI, PN->getType(), ValueVTs);
      for (unsigned vti = 0, vte = ValueVTs.size(); vti != vte; ++vti) {
        EVT VT = ValueVTs[vti];
        unsigned NumRegisters = TLI->getNumRegisters(Fn->getContext(), VT);
        const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
        for (unsigned i = 0; i != NumRegisters; ++i)
          BuildMI(MBB, DL, TII->get(TargetOpcode::PHI), PHIReg + i);
        PHIReg += NumRegisters;
      }
    }
  }

  // Mark landing pad blocks.
  for (BB = Fn->begin(); BB != EB; ++BB)
    if (const InvokeInst *Invoke = dyn_cast<InvokeInst>(BB->getTerminator()))
      MBBMap[Invoke->getSuccessor(1)]->setIsLandingPad();
}
Beispiel #29
0
void LiveIntervals::addKillFlags(const VirtRegMap *VRM) {
  // Keep track of regunit ranges.
  SmallVector<std::pair<LiveInterval*, LiveInterval::iterator>, 8> RU;

  for (unsigned i = 0, e = MRI->getNumVirtRegs(); i != e; ++i) {
    unsigned Reg = TargetRegisterInfo::index2VirtReg(i);
    if (MRI->reg_nodbg_empty(Reg))
      continue;
    LiveInterval *LI = &getInterval(Reg);
    if (LI->empty())
      continue;

    // Find the regunit intervals for the assigned register. They may overlap
    // the virtual register live range, cancelling any kills.
    RU.clear();
    for (MCRegUnitIterator Units(VRM->getPhys(Reg), TRI); Units.isValid();
         ++Units) {
      LiveInterval *RUInt = &getRegUnit(*Units);
      if (RUInt->empty())
        continue;
      RU.push_back(std::make_pair(RUInt, RUInt->find(LI->begin()->end)));
    }

    // Every instruction that kills Reg corresponds to a live range end point.
    for (LiveInterval::iterator RI = LI->begin(), RE = LI->end(); RI != RE;
         ++RI) {
      // A block index indicates an MBB edge.
      if (RI->end.isBlock())
        continue;
      MachineInstr *MI = getInstructionFromIndex(RI->end);
      if (!MI)
        continue;

      // Check if any of the reguints are live beyond the end of RI. That could
      // happen when a physreg is defined as a copy of a virtreg:
      //
      //   %EAX = COPY %vreg5
      //   FOO %vreg5         <--- MI, cancel kill because %EAX is live.
      //   BAR %EAX<kill>
      //
      // There should be no kill flag on FOO when %vreg5 is rewritten as %EAX.
      bool CancelKill = false;
      for (unsigned u = 0, e = RU.size(); u != e; ++u) {
        LiveInterval *RInt = RU[u].first;
        LiveInterval::iterator &I = RU[u].second;
        if (I == RInt->end())
          continue;
        I = RInt->advanceTo(I, RI->end);
        if (I == RInt->end() || I->start >= RI->end)
          continue;
        // I is overlapping RI.
        CancelKill = true;
        break;
      }
      if (CancelKill)
        MI->clearRegisterKills(Reg, NULL);
      else
        MI->addRegisterKilled(Reg, NULL);
    }
  }
}
Beispiel #30
0
unsigned 
JITDwarfEmitter::GetExceptionTableSizeInBytes(MachineFunction* MF) const {
  unsigned FinalSize = 0;

  // Map all labels and get rid of any dead landing pads.
  MMI->TidyLandingPads();

  const std::vector<GlobalVariable *> &TypeInfos = MMI->getTypeInfos();
  const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
  const std::vector<LandingPadInfo> &PadInfos = MMI->getLandingPads();
  if (PadInfos.empty()) return 0;

  // Sort the landing pads in order of their type ids.  This is used to fold
  // duplicate actions.
  SmallVector<const LandingPadInfo *, 64> LandingPads;
  LandingPads.reserve(PadInfos.size());
  for (unsigned i = 0, N = PadInfos.size(); i != N; ++i)
    LandingPads.push_back(&PadInfos[i]);
  std::sort(LandingPads.begin(), LandingPads.end(), PadLT);

  // Negative type ids index into FilterIds, positive type ids index into
  // TypeInfos.  The value written for a positive type id is just the type
  // id itself.  For a negative type id, however, the value written is the
  // (negative) byte offset of the corresponding FilterIds entry.  The byte
  // offset is usually equal to the type id, because the FilterIds entries
  // are written using a variable width encoding which outputs one byte per
  // entry as long as the value written is not too large, but can differ.
  // This kind of complication does not occur for positive type ids because
  // type infos are output using a fixed width encoding.
  // FilterOffsets[i] holds the byte offset corresponding to FilterIds[i].
  SmallVector<int, 16> FilterOffsets;
  FilterOffsets.reserve(FilterIds.size());
  int Offset = -1;
  for(std::vector<unsigned>::const_iterator I = FilterIds.begin(),
    E = FilterIds.end(); I != E; ++I) {
    FilterOffsets.push_back(Offset);
    Offset -= MCAsmInfo::getULEB128Size(*I);
  }

  // Compute the actions table and gather the first action index for each
  // landing pad site.
  SmallVector<ActionEntry, 32> Actions;
  SmallVector<unsigned, 64> FirstActions;
  FirstActions.reserve(LandingPads.size());

  int FirstAction = 0;
  unsigned SizeActions = 0;
  for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
    const LandingPadInfo *LP = LandingPads[i];
    const std::vector<int> &TypeIds = LP->TypeIds;
    const unsigned NumShared = i ? SharedTypeIds(LP, LandingPads[i-1]) : 0;
    unsigned SizeSiteActions = 0;

    if (NumShared < TypeIds.size()) {
      unsigned SizeAction = 0;
      ActionEntry *PrevAction = 0;

      if (NumShared) {
        const unsigned SizePrevIds = LandingPads[i-1]->TypeIds.size();
        assert(Actions.size());
        PrevAction = &Actions.back();
        SizeAction = MCAsmInfo::getSLEB128Size(PrevAction->NextAction) +
          MCAsmInfo::getSLEB128Size(PrevAction->ValueForTypeID);
        for (unsigned j = NumShared; j != SizePrevIds; ++j) {
          SizeAction -= MCAsmInfo::getSLEB128Size(PrevAction->ValueForTypeID);
          SizeAction += -PrevAction->NextAction;
          PrevAction = PrevAction->Previous;
        }
      }

      // Compute the actions.
      for (unsigned I = NumShared, M = TypeIds.size(); I != M; ++I) {
        int TypeID = TypeIds[I];
        assert(-1-TypeID < (int)FilterOffsets.size() && "Unknown filter id!");
        int ValueForTypeID = TypeID < 0 ? FilterOffsets[-1 - TypeID] : TypeID;
        unsigned SizeTypeID = MCAsmInfo::getSLEB128Size(ValueForTypeID);

        int NextAction = SizeAction ? -(SizeAction + SizeTypeID) : 0;
        SizeAction = SizeTypeID + MCAsmInfo::getSLEB128Size(NextAction);
        SizeSiteActions += SizeAction;

        ActionEntry Action = {ValueForTypeID, NextAction, PrevAction};
        Actions.push_back(Action);

        PrevAction = &Actions.back();
      }

      // Record the first action of the landing pad site.
      FirstAction = SizeActions + SizeSiteActions - SizeAction + 1;
    } // else identical - re-use previous FirstAction

    FirstActions.push_back(FirstAction);

    // Compute this sites contribution to size.
    SizeActions += SizeSiteActions;
  }

  // Compute the call-site table.  Entries must be ordered by address.
  SmallVector<CallSiteEntry, 64> CallSites;

  RangeMapType PadMap;
  for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
    const LandingPadInfo *LandingPad = LandingPads[i];
    for (unsigned j=0, E = LandingPad->BeginLabels.size(); j != E; ++j) {
      unsigned BeginLabel = LandingPad->BeginLabels[j];
      assert(!PadMap.count(BeginLabel) && "Duplicate landing pad labels!");
      PadRange P = { i, j };
      PadMap[BeginLabel] = P;
    }
  }

  bool MayThrow = false;
  unsigned LastLabel = 0;
  for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
        I != E; ++I) {
    for (MachineBasicBlock::const_iterator MI = I->begin(), E = I->end();
          MI != E; ++MI) {
      if (!MI->isLabel()) {
        MayThrow |= MI->getDesc().isCall();
        continue;
      }

      unsigned BeginLabel = MI->getOperand(0).getImm();
      assert(BeginLabel && "Invalid label!");

      if (BeginLabel == LastLabel)
        MayThrow = false;

      RangeMapType::iterator L = PadMap.find(BeginLabel);

      if (L == PadMap.end())
        continue;

      PadRange P = L->second;
      const LandingPadInfo *LandingPad = LandingPads[P.PadIndex];

      assert(BeginLabel == LandingPad->BeginLabels[P.RangeIndex] &&
              "Inconsistent landing pad map!");

      // If some instruction between the previous try-range and this one may
      // throw, create a call-site entry with no landing pad for the region
      // between the try-ranges.
      if (MayThrow) {
        CallSiteEntry Site = {LastLabel, BeginLabel, 0, 0};
        CallSites.push_back(Site);
      }

      LastLabel = LandingPad->EndLabels[P.RangeIndex];
      CallSiteEntry Site = {BeginLabel, LastLabel,
        LandingPad->LandingPadLabel, FirstActions[P.PadIndex]};

      assert(Site.BeginLabel && Site.EndLabel && Site.PadLabel &&
              "Invalid landing pad!");

      // Try to merge with the previous call-site.
      if (CallSites.size()) {
        CallSiteEntry &Prev = CallSites.back();
        if (Site.PadLabel == Prev.PadLabel && Site.Action == Prev.Action) {
          // Extend the range of the previous entry.
          Prev.EndLabel = Site.EndLabel;
          continue;
        }
      }

      // Otherwise, create a new call-site.
      CallSites.push_back(Site);
    }
  }
  // If some instruction between the previous try-range and the end of the
  // function may throw, create a call-site entry with no landing pad for the
  // region following the try-range.
  if (MayThrow) {
    CallSiteEntry Site = {LastLabel, 0, 0, 0};
    CallSites.push_back(Site);
  }

  // Final tallies.
  unsigned SizeSites = CallSites.size() * (sizeof(int32_t) + // Site start.
                                            sizeof(int32_t) + // Site length.
                                            sizeof(int32_t)); // Landing pad.
  for (unsigned i = 0, e = CallSites.size(); i < e; ++i)
    SizeSites += MCAsmInfo::getULEB128Size(CallSites[i].Action);

  unsigned SizeTypes = TypeInfos.size() * TD->getPointerSize();

  unsigned TypeOffset = sizeof(int8_t) + // Call site format
                        // Call-site table length
                        MCAsmInfo::getULEB128Size(SizeSites) + 
                        SizeSites + SizeActions + SizeTypes;

  unsigned TotalSize = sizeof(int8_t) + // LPStart format
                       sizeof(int8_t) + // TType format
                       MCAsmInfo::getULEB128Size(TypeOffset) + // TType base offset
                       TypeOffset;

  unsigned SizeAlign = (4 - TotalSize) & 3;

  // Begin the exception table.
  FinalSize = RoundUpToAlign(FinalSize, 4);
  for (unsigned i = 0; i != SizeAlign; ++i) {
    ++FinalSize;
  }
  
  unsigned PointerSize = TD->getPointerSize();

  // Emit the header.
  ++FinalSize;
  // Asm->EOL("LPStart format (DW_EH_PE_omit)");
  ++FinalSize;
  // Asm->EOL("TType format (DW_EH_PE_absptr)");
  ++FinalSize;
  // Asm->EOL("TType base offset");
  ++FinalSize;
  // Asm->EOL("Call site format (DW_EH_PE_udata4)");
  ++FinalSize;
  // Asm->EOL("Call-site table length");

  // Emit the landing pad site information.
  for (unsigned i = 0; i < CallSites.size(); ++i) {
    CallSiteEntry &S = CallSites[i];

    // Asm->EOL("Region start");
    FinalSize += PointerSize;
    
    //Asm->EOL("Region length");
    FinalSize += PointerSize;

    // Asm->EOL("Landing pad");
    FinalSize += PointerSize;

    FinalSize += MCAsmInfo::getULEB128Size(S.Action);
    // Asm->EOL("Action");
  }

  // Emit the actions.
  for (unsigned I = 0, N = Actions.size(); I != N; ++I) {
    ActionEntry &Action = Actions[I];

    //Asm->EOL("TypeInfo index");
    FinalSize += MCAsmInfo::getSLEB128Size(Action.ValueForTypeID);
    //Asm->EOL("Next action");
    FinalSize += MCAsmInfo::getSLEB128Size(Action.NextAction);
  }

  // Emit the type ids.
  for (unsigned M = TypeInfos.size(); M; --M) {
    // Asm->EOL("TypeInfo");
    FinalSize += PointerSize;
  }

  // Emit the filter typeids.
  for (unsigned j = 0, M = FilterIds.size(); j < M; ++j) {
    unsigned TypeID = FilterIds[j];
    FinalSize += MCAsmInfo::getULEB128Size(TypeID);
    //Asm->EOL("Filter TypeInfo index");
  }
  
  FinalSize = RoundUpToAlign(FinalSize, 4);

  return FinalSize;
}