C++ iterator::getNumOperands方法代码示例

bool ARM64PromoteConstant::runOnFunction(Function &F) {
  // Look for instructions using constant vector
  // Promote that constant to a global variable.
  // Create as few load of this variable as possible and update the uses
  // accordingly
  bool LocalChange = false;
  SmallSet<Constant *, 8> AlreadyChecked;
  
  for (Function::iterator IBB = F.begin(), IEndBB = F.end();
       IBB != IEndBB; ++IBB) {
    for (BasicBlock::iterator II = IBB->begin(), IEndI = IBB->end();
         II != IEndI; ++II) {
      // Traverse the operand, looking for constant vectors
      // Replace them by a load of a global variable of type constant vector
      for (unsigned OpIdx = 0, EndOpIdx = II->getNumOperands();
           OpIdx != EndOpIdx; ++OpIdx) {
        Constant *Cst = dyn_cast<Constant>(II->getOperand(OpIdx));
        // There is no point is promoting global value, they are already global.
        // Do not promote constant expression, as they may require some code
        // expansion.
        if (Cst && !isa<GlobalValue>(Cst) && !isa<ConstantExpr>(Cst) &&
            AlreadyChecked.insert(Cst))
          LocalChange |= promoteConstant(Cst);
        
      }
    }
  }
  return LocalChange;
}

bool llvm::ValueCounter::runOnModule(Module& M) {

	std::set<Value*> values;

	for(Module::iterator Fit = M.begin(), Fend = M.end(); Fit != Fend; Fit++){

		if (!values.count(Fit)) values.insert(Fit);

		for(Function::arg_iterator Arg = Fit->arg_begin(), aEnd = Fit->arg_end(); Arg != aEnd; Arg++) {
			if (!values.count(Arg)) values.insert(Arg);
		}

		for (Function::iterator BBit = Fit->begin(), BBend = Fit->end(); BBit != BBend; BBit++) {

			for (BasicBlock::iterator Iit = BBit->begin(), Iend = BBit->end(); Iit != Iend; Iit++) {

				if (!values.count(Iit)) values.insert(Iit);

				for(unsigned int i = 0; i < Iit->getNumOperands(); i++){

					if (!values.count(Iit->getOperand(i))) values.insert(Iit->getOperand(i));

				}
			}
		}
	}
	TotalValues = values.size();

	//We don't modify anything, so we must return false;
	return false;
}

void LowerEmAsyncify::FindContextVariables(AsyncCallEntry & Entry) {
  BasicBlock *AfterCallBlock = Entry.AfterCallBlock;

  Function & F = *AfterCallBlock->getParent();

  // Create a new entry block as if in the callback function
  // theck check variables that no longer properly dominate their uses
  BasicBlock *EntryBlock = BasicBlock::Create(TheModule->getContext(), "", &F, &F.getEntryBlock());
  BranchInst::Create(AfterCallBlock, EntryBlock);

  DominatorTreeWrapperPass DTW;
  DTW.runOnFunction(F);
  DominatorTree& DT = DTW.getDomTree();

  // These blocks may be using some values defined at or before AsyncCallBlock
  BasicBlockSet Ramifications = FindReachableBlocksFrom(AfterCallBlock); 

  SmallPtrSet<Value*, 256> ContextVariables;
  Values Pending;

  // Examine the instructions, find all variables that we need to store in the context
  for (BasicBlockSet::iterator RI = Ramifications.begin(), RE = Ramifications.end(); RI != RE; ++RI) {
    for (BasicBlock::iterator I = (*RI)->begin(), E = (*RI)->end(); I != E; ++I) {
      for (unsigned i = 0, NumOperands = I->getNumOperands(); i < NumOperands; ++i) {
        Value *O = I->getOperand(i);
        if (Instruction *Inst = dyn_cast<Instruction>(O)) {
          if (Inst == Entry.AsyncCallInst) continue; // for the original async call, we will load directly from async return value
          if (ContextVariables.count(Inst) != 0)  continue; // already examined 

          if (!DT.dominates(Inst, I->getOperandUse(i))) {
            // `I` is using `Inst`, yet `Inst` does not dominate `I` if we arrive directly at AfterCallBlock
            // so we need to save `Inst` in the context
            ContextVariables.insert(Inst);
            Pending.push_back(Inst);
          }
        } else if (Argument *Arg = dyn_cast<Argument>(O)) {
          // count() should be as fast/slow as insert, so just insert here 
          ContextVariables.insert(Arg);
        }
      }
    }
  }

  // restore F
  EntryBlock->eraseFromParent();  

  Entry.ContextVariables.clear();
  Entry.ContextVariables.reserve(ContextVariables.size());
  for (SmallPtrSet<Value*, 256>::iterator I = ContextVariables.begin(), E = ContextVariables.end(); I != E; ++I) {
    Entry.ContextVariables.push_back(*I);
  }
}

void LTOModule::addDefinedFunctionSymbol(Function* f, Mangler &mangler)
{
    // add to list of defined symbols
    addDefinedSymbol(f, mangler, true); 

    // add external symbols referenced by this function.
    for (Function::iterator b = f->begin(); b != f->end(); ++b) {
        for (BasicBlock::iterator i = b->begin(); i != b->end(); ++i) {
            for (unsigned count = 0, total = i->getNumOperands(); 
                                        count != total; ++count) {
                findExternalRefs(i->getOperand(count), mangler);
            }
        }
    }
}

/// eliminateUnconditionalBranch - Clone the instructions from the destination
/// block into the source block, eliminating the specified unconditional branch.
/// If the destination block defines values used by successors of the dest
/// block, we may need to insert PHI nodes.
///
void TailDup::eliminateUnconditionalBranch(BranchInst *Branch) {
  BasicBlock *SourceBlock = Branch->getParent();
  BasicBlock *DestBlock = Branch->getSuccessor(0);
  assert(SourceBlock != DestBlock && "Our predicate is broken!");

  DEBUG(errs() << "TailDuplication[" << SourceBlock->getParent()->getName()
        << "]: Eliminating branch: " << *Branch);

  // See if we can avoid duplicating code by moving it up to a dominator of both
  // blocks.
  if (BasicBlock *DomBlock = FindObviousSharedDomOf(SourceBlock, DestBlock)) {
    DEBUG(errs() << "Found shared dominator: " << DomBlock->getName() << "\n");

    // If there are non-phi instructions in DestBlock that have no operands
    // defined in DestBlock, and if the instruction has no side effects, we can
    // move the instruction to DomBlock instead of duplicating it.
    BasicBlock::iterator BBI = DestBlock->getFirstNonPHI();
    while (!isa<TerminatorInst>(BBI)) {
      Instruction *I = BBI++;

      bool CanHoist = I->isSafeToSpeculativelyExecute() &&
                      !I->mayReadFromMemory();
      if (CanHoist) {
        for (unsigned op = 0, e = I->getNumOperands(); op != e; ++op)
          if (Instruction *OpI = dyn_cast<Instruction>(I->getOperand(op)))
            if (OpI->getParent() == DestBlock ||
                (isa<InvokeInst>(OpI) && OpI->getParent() == DomBlock)) {
              CanHoist = false;
              break;
            }
        if (CanHoist) {
          // Remove from DestBlock, move right before the term in DomBlock.
          DestBlock->getInstList().remove(I);
          DomBlock->getInstList().insert(DomBlock->getTerminator(), I);
          DEBUG(errs() << "Hoisted: " << *I);
        }
      }
    }
  }

  // Tail duplication can not update SSA properties correctly if the values
  // defined in the duplicated tail are used outside of the tail itself.  For
  // this reason, we spill all values that are used outside of the tail to the
  // stack.
  for (BasicBlock::iterator I = DestBlock->begin(); I != DestBlock->end(); ++I)
    if (I->isUsedOutsideOfBlock(DestBlock)) {
      // We found a use outside of the tail.  Create a new stack slot to
      // break this inter-block usage pattern.
      DemoteRegToStack(*I);
    }

  // We are going to have to map operands from the original block B to the new
  // copy of the block B'.  If there are PHI nodes in the DestBlock, these PHI
  // nodes also define part of this mapping.  Loop over these PHI nodes, adding
  // them to our mapping.
  //
  std::map<Value*, Value*> ValueMapping;

  BasicBlock::iterator BI = DestBlock->begin();
  bool HadPHINodes = isa<PHINode>(BI);
  for (; PHINode *PN = dyn_cast<PHINode>(BI); ++BI)
    ValueMapping[PN] = PN->getIncomingValueForBlock(SourceBlock);

  // Clone the non-phi instructions of the dest block into the source block,
  // keeping track of the mapping...
  //
  for (; BI != DestBlock->end(); ++BI) {
    Instruction *New = BI->clone();
    New->setName(BI->getName());
    SourceBlock->getInstList().push_back(New);
    ValueMapping[BI] = New;
  }

  // Now that we have built the mapping information and cloned all of the
  // instructions (giving us a new terminator, among other things), walk the new
  // instructions, rewriting references of old instructions to use new
  // instructions.
  //
  BI = Branch; ++BI;  // Get an iterator to the first new instruction
  for (; BI != SourceBlock->end(); ++BI)
    for (unsigned i = 0, e = BI->getNumOperands(); i != e; ++i) {
      std::map<Value*, Value*>::const_iterator I =
        ValueMapping.find(BI->getOperand(i));
      if (I != ValueMapping.end())
        BI->setOperand(i, I->second);
    }

  // Next we check to see if any of the successors of DestBlock had PHI nodes.
  // If so, we need to add entries to the PHI nodes for SourceBlock now.
  for (succ_iterator SI = succ_begin(DestBlock), SE = succ_end(DestBlock);
       SI != SE; ++SI) {
    BasicBlock *Succ = *SI;
    for (BasicBlock::iterator PNI = Succ->begin(); isa<PHINode>(PNI); ++PNI) {
      PHINode *PN = cast<PHINode>(PNI);
      // Ok, we have a PHI node.  Figure out what the incoming value was for the
//.........这里部分代码省略.........

bool GenericToNVVM::runOnModule(Module &M) {
  // Create a clone of each global variable that has the default address space.
  // The clone is created with the global address space  specifier, and the pair
  // of original global variable and its clone is placed in the GVMap for later
  // use.

  for (Module::global_iterator I = M.global_begin(), E = M.global_end();
       I != E;) {
    GlobalVariable *GV = &*I++;
    if (GV->getType()->getAddressSpace() == llvm::ADDRESS_SPACE_GENERIC &&
        !llvm::isTexture(*GV) && !llvm::isSurface(*GV) &&
        !llvm::isSampler(*GV) && !GV->getName().startswith("llvm.")) {
      GlobalVariable *NewGV = new GlobalVariable(
          M, GV->getValueType(), GV->isConstant(),
          GV->getLinkage(),
          GV->hasInitializer() ? GV->getInitializer() : nullptr,
          "", GV, GV->getThreadLocalMode(), llvm::ADDRESS_SPACE_GLOBAL);
      NewGV->copyAttributesFrom(GV);
      GVMap[GV] = NewGV;
    }
  }

  // Return immediately, if every global variable has a specific address space
  // specifier.
  if (GVMap.empty()) {
    return false;
  }

  // Walk through the instructions in function defitinions, and replace any use
  // of original global variables in GVMap with a use of the corresponding
  // copies in GVMap.  If necessary, promote constants to instructions.
  for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
    if (I->isDeclaration()) {
      continue;
    }
    IRBuilder<> Builder(I->getEntryBlock().getFirstNonPHIOrDbg());
    for (Function::iterator BBI = I->begin(), BBE = I->end(); BBI != BBE;
         ++BBI) {
      for (BasicBlock::iterator II = BBI->begin(), IE = BBI->end(); II != IE;
           ++II) {
        for (unsigned i = 0, e = II->getNumOperands(); i < e; ++i) {
          Value *Operand = II->getOperand(i);
          if (isa<Constant>(Operand)) {
            II->setOperand(
                i, remapConstant(&M, &*I, cast<Constant>(Operand), Builder));
          }
        }
      }
    }
    ConstantToValueMap.clear();
  }

  // Copy GVMap over to a standard value map.
  ValueToValueMapTy VM;
  for (auto I = GVMap.begin(), E = GVMap.end(); I != E; ++I)
    VM[I->first] = I->second;

  // Walk through the metadata section and update the debug information
  // associated with the global variables in the default address space.
  for (NamedMDNode &I : M.named_metadata()) {
    remapNamedMDNode(VM, &I);
  }

  // Walk through the global variable  initializers, and replace any use of
  // original global variables in GVMap with a use of the corresponding copies
  // in GVMap.  The copies need to be bitcast to the original global variable
  // types, as we cannot use cvta in global variable initializers.
  for (GVMapTy::iterator I = GVMap.begin(), E = GVMap.end(); I != E;) {
    GlobalVariable *GV = I->first;
    GlobalVariable *NewGV = I->second;

    // Remove GV from the map so that it can be RAUWed.  Note that
    // DenseMap::erase() won't invalidate any iterators but this one.
    auto Next = std::next(I);
    GVMap.erase(I);
    I = Next;

    Constant *BitCastNewGV = ConstantExpr::getPointerCast(NewGV, GV->getType());
    // At this point, the remaining uses of GV should be found only in global
    // variable initializers, as other uses have been already been removed
    // while walking through the instructions in function definitions.
    GV->replaceAllUsesWith(BitCastNewGV);
    std::string Name = GV->getName();
    GV->eraseFromParent();
    NewGV->setName(Name);
  }
  assert(GVMap.empty() && "Expected it to be empty by now");

  return true;
}

void SuperBlock::fixSideEntrances() {
    // due to merging of BBs, some superblocks may have 1 BB remaining
    list<map<BasicBlock*, list<BasicBlock*> >::iterator > delSuperBlocks;

    for (map<BasicBlock*, list<BasicBlock*> >::iterator sp = superBlocks.begin(),
            sp_e = superBlocks.end();  sp != sp_e; ++sp) {
        // we need to keep track of the predecessor of the current basic block
        // being checked
        BasicBlock* prev = sp->first;

        // don't clone basic blocks if the code size threshold is achieved
        if (currCodeSize/originalCodeSize > CODE_EXPANSION_THRESHOLD) {
            break;
        }

        // the first basic block for a superblock need not be duplicated
        for (list<BasicBlock*>::iterator bb = sp->second.begin(),
                bb_e = sp->second.end(); bb != bb_e; ++bb) {
            // first, collect all predecessors for this BB
            // (note: we could not just iterate through as the predecessor set may
            // change
            list<BasicBlock*> predBBs;
            for (pred_iterator pred = pred_begin(*bb), pred_e = pred_end(*bb);
                    pred != pred_e; ++pred) {
                predBBs.push_back(*pred);
            }

            // now, walk through all predecessors of this current basic block
            BasicBlock* clonedBB = NULL;
            for (list<BasicBlock*>::iterator pred = predBBs.begin(),
                    pred_e = predBBs.end(); pred != pred_e; ++pred) {
                // if it is not the predecessor of this current basic block present in
                // the superblock, duplicate!
                if (*pred != prev) {
                    // there is no need to clone this BB multiple times
                    if (clonedBB == NULL) {
                        ValueToValueMapTy vmap;

                        // clone this basic block, and place the corresponding code after
                        // the last BB of this superblock
                        clonedBB = CloneBasicBlock(*bb, vmap, ".cloned",
                                                   (*bb)->getParent());
                        vmap[*bb] = clonedBB;

                        /*
                        errs() << "@@ BEFORE: " << *clonedBB << "\n";
                        // fix phi nodes in the cloned BB
                        for (BasicBlock::iterator I = clonedBB->begin(); isa<PHINode>(I); ++I) {
                          PHINode* PN = dyn_cast<PHINode>(I);
                          int bbIdx = PN->getBasicBlockIndex(prev);
                          if (bbIdx != -1) {
                            PN->removeIncomingValue(bbIdx, false);
                          }
                        }
                        */

                        // add size of duplicated BBs to total code size count
                        currCodeSize += clonedBB->size();

                        // modify operands in this basic block
                        for (BasicBlock::iterator instr = clonedBB->begin(),
                                instr_e = clonedBB->end(); instr != instr_e; ++instr) {
                            for (unsigned idx = 0, num_ops = instr->getNumOperands();
                                    idx < num_ops; ++idx) {
                                Value* op = instr->getOperand(idx);
                                ValueToValueMapTy::iterator op_it = vmap.find(op);
                                if (op_it != vmap.end()) {
                                    instr->setOperand(idx, op_it->second);
                                }
                            }
                        }
                    }

                    // remove phi nodes into this BB in the trace
                    /*
                    for (BasicBlock::iterator I = (*bb)->begin(); isa<PHINode>(I); ++I) {
                      PHINode* PN = dyn_cast<PHINode>(I);
                      int bbIdx = PN->getBasicBlockIndex(*pred);
                      if (bbIdx != -1) {
                        PN->removeIncomingValue(bbIdx, false);
                      }
                    }
                    */

                    // modify the branch instruction of the predecessor not in the superblock to
                    // branch to the cloned basic block
                    Instruction* br_instr = (*pred)->getTerminator();
                    br_instr->replaceUsesOfWith((Value*)*bb, (Value*)clonedBB);
                }
            }

            // determine if we can merge the BB (definitely can be merged), and its clone
            // with theirpredecessors
            if (clonedBB != NULL) {
                if (MergeBlockIntoPredecessor(*bb, this)) {
                    // since we have merged this BB, delete from our superblock mappings
                    partOfSuperBlock.erase(*bb);
                    bb = sp->second.erase(bb);
                    --bb;

//.........这里部分代码省略.........

/// InputFilename is a LLVM bitcode file. Read it using bitcode reader.
/// Collect global functions and symbol names in symbols vector.
/// Collect external references in references vector.
/// Return LTO_READ_SUCCESS if there is no error.
enum LTOStatus
LTO::readLLVMObjectFile(const std::string &InputFilename,
                        NameToSymbolMap &symbols,
                        std::set<std::string> &references)
{
  Module *m = getModule(InputFilename);
  if (!m)
    return LTO_READ_FAILURE;

  // Collect Target info
  getTarget(m);

  if (!Target)
    return LTO_READ_FAILURE;
  
  // Use mangler to add GlobalPrefix to names to match linker names.
  // FIXME : Instead of hard coding "-" use GlobalPrefix.
  Mangler mangler(*m, Target->getTargetAsmInfo()->getGlobalPrefix());
  modules.push_back(m);
  
  for (Module::iterator f = m->begin(), e = m->end(); f != e; ++f) {
    LTOLinkageTypes lt = getLTOLinkageType(f);
    LTOVisibilityTypes vis = getLTOVisibilityType(f);
    if (!f->isDeclaration() && lt != LTOInternalLinkage
        && strncmp (f->getName().c_str(), "llvm.", 5)) {
      int alignment = ( 16 > f->getAlignment() ? 16 : f->getAlignment());
      LLVMSymbol *newSymbol = new LLVMSymbol(lt, vis, f, f->getName(), 
                                             mangler.getValueName(f),
                                             Log2_32(alignment));
      symbols[newSymbol->getMangledName()] = newSymbol;
      allSymbols[newSymbol->getMangledName()] = newSymbol;
    }

    // Collect external symbols referenced by this function.
    for (Function::iterator b = f->begin(), fe = f->end(); b != fe; ++b) 
      for (BasicBlock::iterator i = b->begin(), be = b->end(); 
           i != be; ++i) {
        for (unsigned count = 0, total = i->getNumOperands(); 
             count != total; ++count)
          findExternalRefs(i->getOperand(count), references, mangler);
      }
  }
    
  for (Module::global_iterator v = m->global_begin(), e = m->global_end();
       v !=  e; ++v) {
    LTOLinkageTypes lt = getLTOLinkageType(v);
    LTOVisibilityTypes vis = getLTOVisibilityType(v);
    if (!v->isDeclaration() && lt != LTOInternalLinkage
        && strncmp (v->getName().c_str(), "llvm.", 5)) {
      const TargetData *TD = Target->getTargetData();
      LLVMSymbol *newSymbol = new LLVMSymbol(lt, vis, v, v->getName(), 
                                             mangler.getValueName(v),
                                             TD->getPreferredAlignmentLog(v));
      symbols[newSymbol->getMangledName()] = newSymbol;
      allSymbols[newSymbol->getMangledName()] = newSymbol;

      for (unsigned count = 0, total = v->getNumOperands(); 
           count != total; ++count)
        findExternalRefs(v->getOperand(count), references, mangler);

    }
  }
  
  return LTO_READ_SUCCESS;
}