// Collect allocas
void AllocaManager::collectMarkedAllocas() {
  NamedRegionTimer Timer("Collect Marked Allocas", "AllocaManager",
                         TimePassesIsEnabled);

  // Weird semantics: If an alloca *ever* appears in a lifetime start or end
  // within the same function, its lifetime begins only at the explicit lifetime
  // starts and ends only at the explicit lifetime ends and function exit
  // points. Otherwise, its lifetime begins in the entry block and it is live
  // everywhere.
  //
  // And so, instead of just walking the entry block to find all the static
  // allocas, we walk the whole body to find the intrinsics so we can find the
  // set of static allocas referenced in the intrinsics.
  for (Function::const_iterator FI = F->begin(), FE = F->end();
       FI != FE; ++FI) {
    for (BasicBlock::const_iterator BI = FI->begin(), BE = FI->end();
         BI != BE; ++BI) {
      const CallInst *CI = dyn_cast<CallInst>(BI);
      if (!CI) continue;

      const Value *Callee = CI->getCalledValue();
      if (Callee == LifetimeStart || Callee == LifetimeEnd) {
        if (const Value *Ptr = getPointerFromIntrinsic(CI)) {
          if (const AllocaInst *AI = isFavorableAlloca(Ptr))
            Allocas.insert(std::make_pair(AI, 0));
        } else if (isa<Instruction>(CI->getArgOperand(1)->stripPointerCasts())) {
          // Oh noes, There's a lifetime intrinsics with something that
          // doesn't appear to resolve to an alloca. This means that it's
          // possible that it may be declaring a lifetime for some escaping
          // alloca. Look out!
          Allocas.clear();
          assert(AllocasByIndex.empty());
          return;
        }
      }
    }
  }

  // All that said, we still want the intrinsics in the order they appear in the
  // block, so that we can represent later ones with earlier ones and skip
  // worrying about dominance, so run through the entry block and index those
  // allocas which we identified above.
  AllocasByIndex.reserve(Allocas.size());
  const BasicBlock *EntryBB = &F->getEntryBlock();
  for (BasicBlock::const_iterator BI = EntryBB->begin(), BE = EntryBB->end();
       BI != BE; ++BI) {
    const AllocaInst *AI = dyn_cast<AllocaInst>(BI);
    if (!AI || !AI->isStaticAlloca()) continue;

    AllocaMap::iterator I = Allocas.find(AI);
    if (I != Allocas.end()) {
      I->second = AllocasByIndex.size();
      AllocasByIndex.push_back(getInfo(AI));
    }
  }
  assert(AllocasByIndex.size() == Allocas.size());
}
예제 #2
0
set<Strator::StratorWorker::LockSet>& Strator::StratorWorker::traverseFunction(const Function& f, LockSet lockSet){
	#ifdef DETAILED_DEBUG
	cerr << " Traversing: " << f.getName().str() << endl;
	#endif
	if("signal_threads" == f.getName().str())
		cerr << "signal" << endl;
	/// This should be OK even if not thread safe
	//TODO: Ali: why OK if not thread safe ?!
	parent->functionMap[f.getName().str()] = true;
	/// If the size of a basic block is 0, then we are in a function declaration.
	if (f.size() == 0){
		set<StratorWorker::LockSet>* emptySet = new set<StratorWorker::LockSet>();
		return *emptySet;
	}

	StratorFunction* sFunc = getStratorFunction(&f);

	/// Check if the function is in the cache
	vector<FunctionCacheEntry>::iterator it;
	for(it = sFunc->functionCache.functionCacheEntries.begin();
			it != sFunc->functionCache.functionCacheEntries.end(); ++it){
		if(it->entryLockSet == lockSet){
			return it->exitLockSets;
		}
	}
	/// Simply ignore recursion
	if(sFunc->onStack){
		set<StratorWorker::LockSet>* emptySet = new set<StratorWorker::LockSet>();
		return *emptySet;
	}

	sFunc->onStack= true;

	/// The function was not in the cache, so a new cache entry is being created for it
	FunctionCacheEntry* functionCacheEntry = new FunctionCacheEntry();
	functionCacheEntry->entryLockSet = lockSet;

	/// Start traversing the statements with the beginning statement of the function
	Function::const_iterator firstBB = f.begin();
	BasicBlock::const_iterator firstInstr = firstBB->begin();
	functionCacheEntry->exitLockSets = traverseStatement(f, firstInstr, lockSet, lockSet);

	/// We processes the current function, it is no longer on the stack
	sFunc->onStack= false;

	/// Add the exit lockset to the summary cache
	sFunc->functionCache.functionCacheEntries.push_back(*functionCacheEntry);

	return functionCacheEntry->exitLockSets;
}
예제 #3
0
파일: TypeGen.cpp 프로젝트: roselone/pmGen
void TypeFinder::Run(const Module &M) {

	AddModuleTypesToPrinter(TP,&M);

    // Get types from the type symbol table.  This gets opaque types referened
    // only through derived named types.
    const TypeSymbolTable &ST = M.getTypeSymbolTable();
    for (TypeSymbolTable::const_iterator TI = ST.begin(), E = ST.end();
           TI != E; ++TI)
		IncorporateType(TI->second);

    // Get types from global variables.
	for (Module::const_global_iterator I = M.global_begin(),
           E = M.global_end(); I != E; ++I) {
        IncorporateType(I->getType());
        if (I->hasInitializer())
          IncorporateValue(I->getInitializer());
    }

    // Get types from aliases.
    for (Module::const_alias_iterator I = M.alias_begin(),
         E = M.alias_end(); I != E; ++I) {
		IncorporateType(I->getType());
        IncorporateValue(I->getAliasee());
    }

    // Get types from functions.
    for (Module::const_iterator FI = M.begin(), E = M.end(); FI != E; ++FI) {
        IncorporateType(FI->getType());

		for (Function::const_iterator BB = FI->begin(), E = FI->end();
             BB != E;++BB)
			for (BasicBlock::const_iterator II = BB->begin(),
               E = BB->end(); II != E; ++II) {
				const Instruction &I = *II;
				// Incorporate the type of the instruction and all its operands.
				IncorporateType(I.getType());
				for (User::const_op_iterator OI = I.op_begin(), OE = I.op_end();
					OI != OE; ++OI)
					IncorporateValue(*OI);
			}
      }
}
예제 #4
0
void buildCallMaps(Module const& M, FunctionsMap& F,
		CallsMap& C) {
    for (Module::const_iterator f = M.begin(); f != M.end(); ++f) {
	if (!f->isDeclaration())
	    F.insert(std::make_pair(f->getFunctionType(), &*f));
	for (Function::const_iterator b = f->begin(); b != f->end(); ++b) {
	    for (BasicBlock::const_iterator i = b->begin(); i != b->end(); ++i)
		if (const CallInst *CI = dyn_cast<CallInst>(&*i)) {
		    if (!isInlineAssembly(CI) && !callToMemoryManStuff(CI))
			C.insert(std::make_pair(getCalleePrototype(CI), CI));
		} else if (const StoreInst *SI = dyn_cast<StoreInst>(&*i)) {
		    const Value *r = SI->getValueOperand();
		    if (hasExtraReference(r) && memoryManStuff(r)) {
			const Function *fn = dyn_cast<Function>(r);
			F.insert(std::make_pair(fn->getFunctionType(), fn));
		    }
		}
	}
    }
}
예제 #5
0
void ModuleSummaryIndexBuilder::computeFunctionSummary(
    const Function &F, BlockFrequencyInfo *BFI) {
  // Summary not currently supported for anonymous functions, they must
  // be renamed.
  if (!F.hasName())
    return;

  unsigned NumInsts = 0;
  // Map from callee ValueId to profile count. Used to accumulate profile
  // counts for all static calls to a given callee.
  DenseMap<const Value *, CalleeInfo> CallGraphEdges;
  DenseSet<const Value *> RefEdges;

  SmallPtrSet<const User *, 8> Visited;
  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) {
      if (!isa<DbgInfoIntrinsic>(I))
        ++NumInsts;

      if (auto CS = ImmutableCallSite(&*I)) {
        auto *CalledFunction = CS.getCalledFunction();
        if (CalledFunction && CalledFunction->hasName() &&
            !CalledFunction->isIntrinsic()) {
          auto ScaledCount = BFI ? BFI->getBlockProfileCount(&*BB) : None;
          auto *CalleeId =
              M->getValueSymbolTable().lookup(CalledFunction->getName());
          CallGraphEdges[CalleeId] +=
              (ScaledCount ? ScaledCount.getValue() : 0);
        }
      }
      findRefEdges(&*I, RefEdges, Visited);
    }

  GlobalValueSummary::GVFlags Flags(F);
  std::unique_ptr<FunctionSummary> FuncSummary =
      llvm::make_unique<FunctionSummary>(Flags, NumInsts);
  FuncSummary->addCallGraphEdges(CallGraphEdges);
  FuncSummary->addRefEdges(RefEdges);
  Index->addGlobalValueSummary(F.getName(), std::move(FuncSummary));
}
/// WriteFunction - Emit a function body to the module stream.
static void WriteFunction(const Function &F, NaClValueEnumerator &VE,
                          NaClBitstreamWriter &Stream) {
  Stream.EnterSubblock(naclbitc::FUNCTION_BLOCK_ID);
  VE.incorporateFunction(F);

  SmallVector<unsigned, 64> Vals;

  // Emit the number of basic blocks, so the reader can create them ahead of
  // time.
  Vals.push_back(VE.getBasicBlocks().size());
  Stream.EmitRecord(naclbitc::FUNC_CODE_DECLAREBLOCKS, Vals);
  Vals.clear();

  // If there are function-local constants, emit them now.
  unsigned CstStart, CstEnd;
  VE.getFunctionConstantRange(CstStart, CstEnd);
  WriteConstants(CstStart, CstEnd, VE, Stream);

  // Keep a running idea of what the instruction ID is.
  unsigned InstID = CstEnd;

  // Finally, emit all the instructions, in order.
  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) {
      if (WriteInstruction(*I, InstID, VE, Stream, Vals) &&
          !I->getType()->isVoidTy())
        ++InstID;
    }

  // Emit names for instructions etc.
  if (PNaClAllowLocalSymbolTables)
    WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);

  VE.purgeFunction();
  Stream.ExitBlock();
}
예제 #7
0
void ValueEnumerator::incorporateFunction(const Function &F) {
  InstructionCount = 0;
  NumModuleValues = Values.size();
  NumModuleMDs = MDs.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<LocalAsMetadata *, 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 (auto *MD = dyn_cast<MetadataAsValue>(&*OI))
          if (auto *Local = dyn_cast<LocalAsMetadata>(MD->getMetadata()))
            // Enumerate metadata after the instructions they might refer to.
            FnLocalMDVector.push_back(Local);
      }

      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]);
}
void NaClValueEnumerator::incorporateFunction(const Function &F) {
  InstructionCount = 0;
  NumModuleValues = Values.size();

  // Make sure no insertions outside of a function.
  assert(FnForwardTypeRefs.empty());

  // 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) {
      if (const SwitchInst *SI = dyn_cast<SwitchInst>(I)) {
        // Handle switch instruction specially, so that we don't write
        // out unnecessary vector/array constants used to model case selectors.
        if (isa<Constant>(SI->getCondition())) {
          EnumerateValue(SI->getCondition());
        }
      } else {
        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());

  FirstInstID = Values.size();

  // 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) {
      if (!I->getType()->isVoidTy())
        EnumerateValue(I);
    }
  }
}
예제 #9
0
void ValueEnumerator::incorporateFunction(const Function &F) {
  NumModuleValues = Values.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();

  // 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) {
      if (I->getType() != Type::getVoidTy(F.getContext()))
        EnumerateValue(I);
    }
  }
}
예제 #10
0
/// analyzeFunction - Fill in the current structure with information gleaned
/// from the specified function.
void InlineCostAnalyzer::FunctionInfo::analyzeFunction(Function *F) {
  unsigned NumInsts = 0, NumBlocks = 0, NumVectorInsts = 0;

  // Look at the size of the callee.  Each basic block counts as 20 units, and
  // each instruction counts as 5.
  for (Function::const_iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
    for (BasicBlock::const_iterator II = BB->begin(), E = BB->end();
         II != E; ++II) {
      if (isa<PHINode>(II)) continue;           // PHI nodes don't count.

      // Special handling for calls.
      if (isa<CallInst>(II) || isa<InvokeInst>(II)) {
        if (isa<DbgInfoIntrinsic>(II))
          continue;  // Debug intrinsics don't count as size.
        
        CallSite CS = CallSite::get(const_cast<Instruction*>(&*II));
        
        // If this function contains a call to setjmp or _setjmp, never inline
        // it.  This is a hack because we depend on the user marking their local
        // variables as volatile if they are live across a setjmp call, and they
        // probably won't do this in callers.
        if (Function *F = CS.getCalledFunction())
          if (F->isDeclaration() && 
              (F->isName("setjmp") || F->isName("_setjmp"))) {
            NeverInline = true;
            return;
          }

        // Calls often compile into many machine instructions.  Bump up their
        // cost to reflect this.
        if (!isa<IntrinsicInst>(II))
          NumInsts += 5;
      }
      
      if (const AllocaInst *AI = dyn_cast<AllocaInst>(II)) {
        if (!AI->isStaticAlloca())
          this->usesDynamicAlloca = true;
      }

      if (isa<ExtractElementInst>(II) || isa<VectorType>(II->getType()))
        ++NumVectorInsts; 
      
      // Noop casts, including ptr <-> int,  don't count.
      if (const CastInst *CI = dyn_cast<CastInst>(II)) {
        if (CI->isLosslessCast() || isa<IntToPtrInst>(CI) || 
            isa<PtrToIntInst>(CI))
          continue;
      } else if (const GetElementPtrInst *GEPI =
                 dyn_cast<GetElementPtrInst>(II)) {
        // If a GEP has all constant indices, it will probably be folded with
        // a load/store.
        bool AllConstant = true;
        for (unsigned i = 1, e = GEPI->getNumOperands(); i != e; ++i)
          if (!isa<ConstantInt>(GEPI->getOperand(i))) {
            AllConstant = false;
            break;
          }
        if (AllConstant) continue;
      }
      
      ++NumInsts;
    }

    ++NumBlocks;
  }

  this->NumBlocks      = NumBlocks;
  this->NumInsts       = NumInsts;
  this->NumVectorInsts = NumVectorInsts;

  // Check out all of the arguments to the function, figuring out how much
  // code can be eliminated if one of the arguments is a constant.
  for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E; ++I)
    ArgumentWeights.push_back(ArgInfo(CountCodeReductionForConstant(I),
                                      CountCodeReductionForAlloca(I)));
}
void FunctionLoweringInfo::set(const Function &fn, MachineFunction &mf,
                               SelectionDAG *DAG) {
  Fn = &fn;
  MF = &mf;
  TLI = MF->getSubtarget().getTargetLowering();
  RegInfo = &MF->getRegInfo();
  MachineModuleInfo &MMI = MF->getMMI();

  // 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 (; BB != EB; ++BB)
    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
         I != E; ++I) {
      if (const AllocaInst *AI = dyn_cast<AllocaInst>(I)) {
        // Static allocas can be folded into the initial stack frame adjustment.
        if (AI->isStaticAlloca()) {
          const ConstantInt *CUI = 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);

        } else {
          unsigned Align = std::max(
              (unsigned)TLI->getDataLayout()->getPrefTypeAlignment(
                AI->getAllocatedType()),
              AI->getAlignment());
          unsigned StackAlign =
              MF->getSubtarget().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();
          const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
          std::vector<TargetLowering::AsmOperandInfo> Ops =
              TLI->ParseConstraints(TRI, 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(TRI, Op.ConstraintCode,
                                                    Op.ConstraintVT);
              if (PhysReg.first == SP)
                MF->getFrameInfo()->setHasInlineAsmWithSPAdjust(true);
            }
          }
        }
      }

      // Look for calls to the @llvm.va_start intrinsic. We can omit some
      // prologue boilerplate for variadic functions that don't examine their
      // arguments.
      if (const auto *II = dyn_cast<IntrinsicInst>(I)) {
        if (II->getIntrinsicID() == Intrinsic::vastart)
          MF->getFrameInfo()->setHasVAStart(true);
      }

      // If we have a musttail call in a variadic funciton, we need to ensure we
      // forward implicit register parameters.
      if (const auto *CI = dyn_cast<CallInst>(I)) {
        if (CI->isMustTailCall() && Fn->isVarArg())
          MF->getFrameInfo()->setHasMustTailInVarArgFunc(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)) {
        assert(DI->getVariable() && "Missing variable");
        assert(DI->getDebugLoc() && "Missing location");
        if (MMI.hasDebugInfo()) {
          // 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(), DI->getExpression(),
                                       FI, DI->getDebugLoc());
              }
            }
          }
        }
      }

      // Decide the preferred extend type for a value.
      PreferredExtendType[I] = getPreferredExtendForValue(I);
    }

  // 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.
  SmallVector<const LandingPadInst *, 4> LPads;
  for (BB = Fn->begin(); BB != EB; ++BB) {
    if (const auto *Invoke = dyn_cast<InvokeInst>(BB->getTerminator()))
      MBBMap[Invoke->getSuccessor(1)]->setIsLandingPad();
    if (BB->isLandingPad())
      LPads.push_back(BB->getLandingPadInst());
  }

  // If this is an MSVC EH personality, we need to do a bit more work.
  EHPersonality Personality = EHPersonality::Unknown;
  if (!LPads.empty())
    Personality = classifyEHPersonality(LPads.back()->getPersonalityFn());
  if (!isMSVCEHPersonality(Personality))
    return;

  if (Personality == EHPersonality::MSVC_Win64SEH ||
      Personality == EHPersonality::MSVC_X86SEH) {
    addSEHHandlersForLPads(LPads);
  }

  WinEHFuncInfo &EHInfo = MMI.getWinEHFuncInfo(&fn);
  if (Personality == EHPersonality::MSVC_CXX) {
    const Function *WinEHParentFn = MMI.getWinEHParent(&fn);
    calculateWinCXXEHStateNumbers(WinEHParentFn, EHInfo);
  }

  // Copy the state numbers to LandingPadInfo for the current function, which
  // could be a handler or the parent. This should happen for 32-bit SEH and
  // C++ EH.
  if (Personality == EHPersonality::MSVC_CXX ||
      Personality == EHPersonality::MSVC_X86SEH) {
    for (const LandingPadInst *LP : LPads) {
      MachineBasicBlock *LPadMBB = MBBMap[LP->getParent()];
      MMI.addWinEHState(LPadMBB, EHInfo.LandingPadStateMap[LP]);
    }
  }
}
예제 #12
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());
}
예제 #13
0
static Error ReduceInsts(BugDriver &BD,
                        bool (*TestFn)(const BugDriver &, Module *)) {
  // Attempt to delete instructions using bisection. This should help out nasty
  // cases with large basic blocks where the problem is at one end.
  if (!BugpointIsInterrupted) {
    std::vector<const Instruction *> Insts;
    for (const Function &F : *BD.getProgram())
      for (const BasicBlock &BB : F)
        for (const Instruction &I : BB)
          if (!isa<TerminatorInst>(&I))
            Insts.push_back(&I);

    Expected<bool> Result =
        ReduceCrashingInstructions(BD, TestFn).reduceList(Insts);
    if (Error E = Result.takeError())
      return E;
  }

  unsigned Simplification = 2;
  do {
    if (BugpointIsInterrupted)
      // TODO: Should we distinguish this with an "interrupted error"?
      return Error::success();
    --Simplification;
    outs() << "\n*** Attempting to reduce testcase by deleting instruc"
           << "tions: Simplification Level #" << Simplification << '\n';

    // Now that we have deleted the functions that are unnecessary for the
    // program, try to remove instructions that are not necessary to cause the
    // crash.  To do this, we loop through all of the instructions in the
    // remaining functions, deleting them (replacing any values produced with
    // nulls), and then running ADCE and SimplifyCFG.  If the transformed input
    // still triggers failure, keep deleting until we cannot trigger failure
    // anymore.
    //
    unsigned InstructionsToSkipBeforeDeleting = 0;
  TryAgain:

    // Loop over all of the (non-terminator) instructions remaining in the
    // function, attempting to delete them.
    unsigned CurInstructionNum = 0;
    for (Module::const_iterator FI = BD.getProgram()->begin(),
                                E = BD.getProgram()->end();
         FI != E; ++FI)
      if (!FI->isDeclaration())
        for (Function::const_iterator BI = FI->begin(), E = FI->end(); BI != E;
             ++BI)
          for (BasicBlock::const_iterator I = BI->begin(), E = --BI->end();
               I != E; ++I, ++CurInstructionNum) {
            if (InstructionsToSkipBeforeDeleting) {
              --InstructionsToSkipBeforeDeleting;
            } else {
              if (BugpointIsInterrupted)
                // TODO: Should this be some kind of interrupted error?
                return Error::success();

              if (I->isEHPad() || I->getType()->isTokenTy())
                continue;

              outs() << "Checking instruction: " << *I;
              std::unique_ptr<Module> M =
                  BD.deleteInstructionFromProgram(&*I, Simplification);

              // Find out if the pass still crashes on this pass...
              if (TestFn(BD, M.get())) {
                // Yup, it does, we delete the old module, and continue trying
                // to reduce the testcase...
                BD.setNewProgram(M.release());
                InstructionsToSkipBeforeDeleting = CurInstructionNum;
                goto TryAgain; // I wish I had a multi-level break here!
              }
            }
          }

    if (InstructionsToSkipBeforeDeleting) {
      InstructionsToSkipBeforeDeleting = 0;
      goto TryAgain;
    }

  } while (Simplification);
  BD.EmitProgressBitcode(BD.getProgram(), "reduced-instructions");
  return Error::success();
}
예제 #14
0
void externalsAndGlobalsCheck(const Module *m) {
  std::map<std::string, bool> externals;
  std::set<std::string> modelled(modelledExternals,
                                 modelledExternals+NELEMS(modelledExternals));
  std::set<std::string> dontCare(dontCareExternals,
                                 dontCareExternals+NELEMS(dontCareExternals));
  std::set<std::string> unsafe(unsafeExternals,
                               unsafeExternals+NELEMS(unsafeExternals));

  switch (Libc) {
  case KleeLibc:
    dontCare.insert(dontCareKlee, dontCareKlee+NELEMS(dontCareKlee));
    break;
  case UcLibc:
    dontCare.insert(dontCareUclibc,
                    dontCareUclibc+NELEMS(dontCareUclibc));
    break;
  case NoLibc: /* silence compiler warning */
    break;
  }

  if (WithPOSIXRuntime)
    dontCare.insert("syscall");

  for (Module::const_iterator fnIt = m->begin(), fn_ie = m->end();
       fnIt != fn_ie; ++fnIt) {
    if (fnIt->isDeclaration() && !fnIt->use_empty())
      externals.insert(std::make_pair(fnIt->getName(), false));
    for (Function::const_iterator bbIt = fnIt->begin(), bb_ie = fnIt->end();
         bbIt != bb_ie; ++bbIt) {
      for (BasicBlock::const_iterator it = bbIt->begin(), ie = bbIt->end();
           it != ie; ++it) {
        if (const CallInst *ci = dyn_cast<CallInst>(it)) {
          if (isa<InlineAsm>(ci->getCalledValue())) {
            klee_warning_once(&*fnIt,
                              "function \"%s\" has inline asm",
                              fnIt->getName().data());
          }
        }
      }
    }
  }
  for (Module::const_global_iterator
         it = m->global_begin(), ie = m->global_end();
       it != ie; ++it)
    if (it->isDeclaration() && !it->use_empty())
      externals.insert(std::make_pair(it->getName(), true));
  // and remove aliases (they define the symbol after global
  // initialization)
  for (Module::const_alias_iterator
         it = m->alias_begin(), ie = m->alias_end();
       it != ie; ++it) {
    std::map<std::string, bool>::iterator it2 =
      externals.find(it->getName());
    if (it2!=externals.end())
      externals.erase(it2);
  }

  std::map<std::string, bool> foundUnsafe;
  for (std::map<std::string, bool>::iterator
         it = externals.begin(), ie = externals.end();
       it != ie; ++it) {
    const std::string &ext = it->first;
    if (!modelled.count(ext) && (WarnAllExternals ||
                                 !dontCare.count(ext))) {
      if (unsafe.count(ext)) {
        foundUnsafe.insert(*it);
      } else {
        klee_warning("undefined reference to %s: %s",
                     it->second ? "variable" : "function",
                     ext.c_str());
      }
    }
  }

  for (std::map<std::string, bool>::iterator
         it = foundUnsafe.begin(), ie = foundUnsafe.end();
       it != ie; ++it) {
    const std::string &ext = it->first;
    klee_warning("undefined reference to %s: %s (UNSAFE)!",
                 it->second ? "variable" : "function",
                 ext.c_str());
  }
}
예제 #15
0
/// CloneAndPruneFunctionInto - This works exactly like CloneFunctionInto,
/// except that it does some simple constant prop and DCE on the fly.  The
/// effect of this is to copy significantly less code in cases where (for
/// example) a function call with constant arguments is inlined, and those
/// constant arguments cause a significant amount of code in the callee to be
/// dead.  Since this doesn't produce an exact copy of the input, it can't be
/// used for things like CloneFunction or CloneModule.
void llvm::CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc,
                                     ValueToValueMapTy &VMap,
                                     bool ModuleLevelChanges,
                                     SmallVectorImpl<ReturnInst*> &Returns,
                                     const char *NameSuffix, 
                                     ClonedCodeInfo *CodeInfo,
                                     const TargetData *TD,
                                     Instruction *TheCall) {
  assert(NameSuffix && "NameSuffix cannot be null!");
  
#ifndef NDEBUG
  for (Function::const_arg_iterator II = OldFunc->arg_begin(), 
       E = OldFunc->arg_end(); II != E; ++II)
    assert(VMap.count(II) && "No mapping from source argument specified!");
#endif

  PruningFunctionCloner PFC(NewFunc, OldFunc, VMap, ModuleLevelChanges,
                            Returns, NameSuffix, CodeInfo, TD);

  // Clone the entry block, and anything recursively reachable from it.
  std::vector<const BasicBlock*> CloneWorklist;
  CloneWorklist.push_back(&OldFunc->getEntryBlock());
  while (!CloneWorklist.empty()) {
    const BasicBlock *BB = CloneWorklist.back();
    CloneWorklist.pop_back();
    PFC.CloneBlock(BB, CloneWorklist);
  }
  
  // Loop over all of the basic blocks in the old function.  If the block was
  // reachable, we have cloned it and the old block is now in the value map:
  // insert it into the new function in the right order.  If not, ignore it.
  //
  // Defer PHI resolution until rest of function is resolved.
  SmallVector<const PHINode*, 16> PHIToResolve;
  for (Function::const_iterator BI = OldFunc->begin(), BE = OldFunc->end();
       BI != BE; ++BI) {
    Value *V = VMap[BI];
    BasicBlock *NewBB = cast_or_null<BasicBlock>(V);
    if (NewBB == 0) continue;  // Dead block.

    // Add the new block to the new function.
    NewFunc->getBasicBlockList().push_back(NewBB);
    
    // Loop over all of the instructions in the block, fixing up operand
    // references as we go.  This uses VMap to do all the hard work.
    //
    BasicBlock::iterator I = NewBB->begin();

    DebugLoc TheCallDL;
    if (TheCall) 
      TheCallDL = TheCall->getDebugLoc();
    
    // Handle PHI nodes specially, as we have to remove references to dead
    // blocks.
    if (PHINode *PN = dyn_cast<PHINode>(I)) {
      // Skip over all PHI nodes, remembering them for later.
      BasicBlock::const_iterator OldI = BI->begin();
      for (; (PN = dyn_cast<PHINode>(I)); ++I, ++OldI)
        PHIToResolve.push_back(cast<PHINode>(OldI));
    }
    
    // Otherwise, remap the rest of the instructions normally.
    for (; I != NewBB->end(); ++I)
      RemapInstruction(I, VMap,
                       ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges);
  }
  
  // Defer PHI resolution until rest of function is resolved, PHI resolution
  // requires the CFG to be up-to-date.
  for (unsigned phino = 0, e = PHIToResolve.size(); phino != e; ) {
    const PHINode *OPN = PHIToResolve[phino];
    unsigned NumPreds = OPN->getNumIncomingValues();
    const BasicBlock *OldBB = OPN->getParent();
    BasicBlock *NewBB = cast<BasicBlock>(VMap[OldBB]);

    // Map operands for blocks that are live and remove operands for blocks
    // that are dead.
    for (; phino != PHIToResolve.size() &&
         PHIToResolve[phino]->getParent() == OldBB; ++phino) {
      OPN = PHIToResolve[phino];
      PHINode *PN = cast<PHINode>(VMap[OPN]);
      for (unsigned pred = 0, e = NumPreds; pred != e; ++pred) {
        Value *V = VMap[PN->getIncomingBlock(pred)];
        if (BasicBlock *MappedBlock = cast_or_null<BasicBlock>(V)) {
          Value *InVal = MapValue(PN->getIncomingValue(pred),
                                  VMap, 
                        ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges);
          assert(InVal && "Unknown input value?");
          PN->setIncomingValue(pred, InVal);
          PN->setIncomingBlock(pred, MappedBlock);
        } else {
          PN->removeIncomingValue(pred, false);
          --pred, --e;  // Revisit the next entry.
        }
      } 
    }
    
    // The loop above has removed PHI entries for those blocks that are dead
    // and has updated others.  However, if a block is live (i.e. copied over)
    // but its terminator has been changed to not go to this block, then our
    // phi nodes will have invalid entries.  Update the PHI nodes in this
    // case.
    PHINode *PN = cast<PHINode>(NewBB->begin());
    NumPreds = std::distance(pred_begin(NewBB), pred_end(NewBB));
    if (NumPreds != PN->getNumIncomingValues()) {
      assert(NumPreds < PN->getNumIncomingValues());
      // Count how many times each predecessor comes to this block.
      std::map<BasicBlock*, unsigned> PredCount;
      for (pred_iterator PI = pred_begin(NewBB), E = pred_end(NewBB);
           PI != E; ++PI)
        --PredCount[*PI];
      
      // Figure out how many entries to remove from each PHI.
      for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
        ++PredCount[PN->getIncomingBlock(i)];
      
      // At this point, the excess predecessor entries are positive in the
      // map.  Loop over all of the PHIs and remove excess predecessor
      // entries.
      BasicBlock::iterator I = NewBB->begin();
      for (; (PN = dyn_cast<PHINode>(I)); ++I) {
        for (std::map<BasicBlock*, unsigned>::iterator PCI =PredCount.begin(),
             E = PredCount.end(); PCI != E; ++PCI) {
          BasicBlock *Pred     = PCI->first;
          for (unsigned NumToRemove = PCI->second; NumToRemove; --NumToRemove)
            PN->removeIncomingValue(Pred, false);
        }
      }
    }
    
    // If the loops above have made these phi nodes have 0 or 1 operand,
    // replace them with undef or the input value.  We must do this for
    // correctness, because 0-operand phis are not valid.
    PN = cast<PHINode>(NewBB->begin());
    if (PN->getNumIncomingValues() == 0) {
      BasicBlock::iterator I = NewBB->begin();
      BasicBlock::const_iterator OldI = OldBB->begin();
      while ((PN = dyn_cast<PHINode>(I++))) {
        Value *NV = UndefValue::get(PN->getType());
        PN->replaceAllUsesWith(NV);
        assert(VMap[OldI] == PN && "VMap mismatch");
        VMap[OldI] = NV;
        PN->eraseFromParent();
        ++OldI;
      }
    }
    // NOTE: We cannot eliminate single entry phi nodes here, because of
    // VMap.  Single entry phi nodes can have multiple VMap entries
    // pointing at them.  Thus, deleting one would require scanning the VMap
    // to update any entries in it that would require that.  This would be
    // really slow.
  }
  
  // Now that the inlined function body has been fully constructed, go through
  // and zap unconditional fall-through branches.  This happen all the time when
  // specializing code: code specialization turns conditional branches into
  // uncond branches, and this code folds them.
  Function::iterator I = cast<BasicBlock>(VMap[&OldFunc->getEntryBlock()]);
  while (I != NewFunc->end()) {
    BranchInst *BI = dyn_cast<BranchInst>(I->getTerminator());
    if (!BI || BI->isConditional()) { ++I; continue; }
    
    // Note that we can't eliminate uncond branches if the destination has
    // single-entry PHI nodes.  Eliminating the single-entry phi nodes would
    // require scanning the VMap to update any entries that point to the phi
    // node.
    BasicBlock *Dest = BI->getSuccessor(0);
    if (!Dest->getSinglePredecessor() || isa<PHINode>(Dest->begin())) {
      ++I; continue;
    }
    
    // We know all single-entry PHI nodes in the inlined function have been
    // removed, so we just need to splice the blocks.
    BI->eraseFromParent();
    
    // Make all PHI nodes that referred to Dest now refer to I as their source.
    Dest->replaceAllUsesWith(I);

    // Move all the instructions in the succ to the pred.
    I->getInstList().splice(I->end(), Dest->getInstList());
    
    // Remove the dest block.
    Dest->eraseFromParent();
    
    // Do not increment I, iteratively merge all things this block branches to.
  }
}
예제 #16
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());

  // Enumerate types used by the type symbol table.
  EnumerateTypeSymbolTable(M->getTypeSymbolTable());

  // 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());

  // Sort the type table by frequency so that most commonly used types are early
  // in the table (have low bit-width).
  std::stable_sort(Types.begin(), Types.end(), CompareByFrequency);

  // Partition the Type ID's so that the single-value types occur before the
  // aggregate types.  This allows the aggregate types to be dropped from the
  // type table after parsing the global variable initializers.
  std::partition(Types.begin(), Types.end(), isSingleValueType);

  // Now that we rearranged the type table, rebuild TypeMap.
  for (unsigned i = 0, e = Types.size(); i != e; ++i)
    TypeMap[Types[i].first] = i+1;
}
예제 #17
0
/// DebugACrash - Given a predicate that determines whether a component crashes
/// on a program, try to destructively reduce the program while still keeping
/// the predicate true.
static bool DebugACrash(BugDriver &BD,
                        bool (*TestFn)(const BugDriver &, Module *),
                        std::string &Error) {
  // See if we can get away with nuking some of the global variable initializers
  // in the program...
  if (!NoGlobalRM &&
      BD.getProgram()->global_begin() != BD.getProgram()->global_end()) {
    // Now try to reduce the number of global variable initializers in the
    // module to something small.
    Module *M = CloneModule(BD.getProgram());
    bool DeletedInit = false;

    for (Module::global_iterator I = M->global_begin(), E = M->global_end();
         I != E; ++I)
      if (I->hasInitializer()) {
        I->setInitializer(nullptr);
        I->setLinkage(GlobalValue::ExternalLinkage);
        DeletedInit = true;
      }

    if (!DeletedInit) {
      delete M;  // No change made...
    } else {
      // See if the program still causes a crash...
      outs() << "\nChecking to see if we can delete global inits: ";

      if (TestFn(BD, M)) {      // Still crashes?
        BD.setNewProgram(M);
        outs() << "\n*** Able to remove all global initializers!\n";
      } else {                  // No longer crashes?
        outs() << "  - Removing all global inits hides problem!\n";
        delete M;

        std::vector<GlobalVariable*> GVs;

        for (Module::global_iterator I = BD.getProgram()->global_begin(),
               E = BD.getProgram()->global_end(); I != E; ++I)
          if (I->hasInitializer())
            GVs.push_back(&*I);

        if (GVs.size() > 1 && !BugpointIsInterrupted) {
          outs() << "\n*** Attempting to reduce the number of global "
                    << "variables in the testcase\n";

          unsigned OldSize = GVs.size();
          ReduceCrashingGlobalVariables(BD, TestFn).reduceList(GVs, Error);
          if (!Error.empty())
            return true;

          if (GVs.size() < OldSize)
            BD.EmitProgressBitcode(BD.getProgram(), "reduced-global-variables");
        }
      }
    }
  }

  // Now try to reduce the number of functions in the module to something small.
  std::vector<Function*> Functions;
  for (Function &F : *BD.getProgram())
    if (!F.isDeclaration())
      Functions.push_back(&F);

  if (Functions.size() > 1 && !BugpointIsInterrupted) {
    outs() << "\n*** Attempting to reduce the number of functions "
      "in the testcase\n";

    unsigned OldSize = Functions.size();
    ReduceCrashingFunctions(BD, TestFn).reduceList(Functions, Error);

    if (Functions.size() < OldSize)
      BD.EmitProgressBitcode(BD.getProgram(), "reduced-function");
  }

  // Attempt to delete entire basic blocks at a time to speed up
  // convergence... this actually works by setting the terminator of the blocks
  // to a return instruction then running simplifycfg, which can potentially
  // shrinks the code dramatically quickly
  //
  if (!DisableSimplifyCFG && !BugpointIsInterrupted) {
    std::vector<const BasicBlock*> Blocks;
    for (Function &F : *BD.getProgram())
      for (BasicBlock &BB : F)
        Blocks.push_back(&BB);
    unsigned OldSize = Blocks.size();
    ReduceCrashingBlocks(BD, TestFn).reduceList(Blocks, Error);
    if (Blocks.size() < OldSize)
      BD.EmitProgressBitcode(BD.getProgram(), "reduced-blocks");
  }

  // Attempt to delete instructions using bisection. This should help out nasty
  // cases with large basic blocks where the problem is at one end.
  if (!BugpointIsInterrupted) {
    std::vector<const Instruction*> Insts;
    for (const Function &F : *BD.getProgram())
      for (const BasicBlock &BB : F)
        for (const Instruction &I : BB)
          if (!isa<TerminatorInst>(&I))
            Insts.push_back(&I);

    ReduceCrashingInstructions(BD, TestFn).reduceList(Insts, Error);
  }

  // FIXME: This should use the list reducer to converge faster by deleting
  // larger chunks of instructions at a time!
  unsigned Simplification = 2;
  do {
    if (BugpointIsInterrupted) break;
    --Simplification;
    outs() << "\n*** Attempting to reduce testcase by deleting instruc"
           << "tions: Simplification Level #" << Simplification << '\n';

    // Now that we have deleted the functions that are unnecessary for the
    // program, try to remove instructions that are not necessary to cause the
    // crash.  To do this, we loop through all of the instructions in the
    // remaining functions, deleting them (replacing any values produced with
    // nulls), and then running ADCE and SimplifyCFG.  If the transformed input
    // still triggers failure, keep deleting until we cannot trigger failure
    // anymore.
    //
    unsigned InstructionsToSkipBeforeDeleting = 0;
  TryAgain:

    // Loop over all of the (non-terminator) instructions remaining in the
    // function, attempting to delete them.
    unsigned CurInstructionNum = 0;
    for (Module::const_iterator FI = BD.getProgram()->begin(),
           E = BD.getProgram()->end(); FI != E; ++FI)
      if (!FI->isDeclaration())
        for (Function::const_iterator BI = FI->begin(), E = FI->end(); BI != E;
             ++BI)
          for (BasicBlock::const_iterator I = BI->begin(), E = --BI->end();
               I != E; ++I, ++CurInstructionNum) {
            if (InstructionsToSkipBeforeDeleting) {
              --InstructionsToSkipBeforeDeleting;
            } else {
              if (BugpointIsInterrupted) goto ExitLoops;

              if (isa<LandingPadInst>(I))
                continue;

              outs() << "Checking instruction: " << *I;
              std::unique_ptr<Module> M =
                  BD.deleteInstructionFromProgram(&*I, Simplification);

              // Find out if the pass still crashes on this pass...
              if (TestFn(BD, M.get())) {
                // Yup, it does, we delete the old module, and continue trying
                // to reduce the testcase...
                BD.setNewProgram(M.release());
                InstructionsToSkipBeforeDeleting = CurInstructionNum;
                goto TryAgain;  // I wish I had a multi-level break here!
              }
            }
          }

    if (InstructionsToSkipBeforeDeleting) {
      InstructionsToSkipBeforeDeleting = 0;
      goto TryAgain;
    }

  } while (Simplification);
ExitLoops:

  // Try to clean up the testcase by running funcresolve and globaldce...
  if (!BugpointIsInterrupted) {
    outs() << "\n*** Attempting to perform final cleanups: ";
    Module *M = CloneModule(BD.getProgram());
    M = BD.performFinalCleanups(M, true).release();

    // Find out if the pass still crashes on the cleaned up program...
    if (TestFn(BD, M)) {
      BD.setNewProgram(M);     // Yup, it does, keep the reduced version...
    } else {
      delete M;
    }
  }

  BD.EmitProgressBitcode(BD.getProgram(), "reduced-simplified");

  return false;
}
예제 #18
0
void FunctionLoweringInfo::set(const Function &fn, MachineFunction &mf) {
  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().getRetAttributes(), 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))
      if (const ConstantInt *CUI = dyn_cast<ConstantInt>(AI->getArraySize())) {
        const Type *Ty = AI->getAllocatedType();
        uint64_t TySize = TLI.getTargetData()->getTypeAllocSize(Ty);
        unsigned Align =
          std::max((unsigned)TLI.getTargetData()->getPrefTypeAlignment(Ty),
                   AI->getAlignment());

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

        // The object may need to be placed onto the stack near the stack
        // protector if one exists. Determine here if this object is a suitable
        // candidate. I.e., it would trigger the creation of a stack protector.
        bool MayNeedSP =
          (AI->isArrayAllocation() ||
           (TySize > 8 && isa<ArrayType>(Ty) &&
            cast<ArrayType>(Ty)->getElementType()->isIntegerTy(8)));
        StaticAllocaMap[AI] =
          MF->getFrameInfo()->CreateStackObject(TySize, Align, false, MayNeedSP);
      }

  for (; BB != EB; ++BB)
    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
      // 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();
        if (MMI.hasDebugInfo() &&
            DIVariable(DI->getVariable()).Verify() &&
            !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->getTarget().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();
}
예제 #19
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);
    EnumerateParamAttrs(cast<Function>(I)->getParamAttrs());
  }

  // 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());
  
  // Enumerate types used by the type symbol table.
  EnumerateTypeSymbolTable(M->getTypeSymbolTable());

  // Insert constants that are named at module level into the slot pool so that
  // the module symbol table can refer to them...
  EnumerateValueSymbolTable(M->getValueSymbolTable());
  
  // 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)
          EnumerateOperandType(*OI);
        EnumerateType(I->getType());
        if (const CallInst *CI = dyn_cast<CallInst>(I))
          EnumerateParamAttrs(CI->getParamAttrs());
        else if (const InvokeInst *II = dyn_cast<InvokeInst>(I))
          EnumerateParamAttrs(II->getParamAttrs());
      }
  }
  
  // Optimize constant ordering.
  OptimizeConstants(FirstConstant, Values.size());
    
  // Sort the type table by frequency so that most commonly used types are early
  // in the table (have low bit-width).
  std::stable_sort(Types.begin(), Types.end(), CompareByFrequency);
    
  // Partition the Type ID's so that the first-class types occur before the
  // aggregate types.  This allows the aggregate types to be dropped from the
  // type table after parsing the global variable initializers.
  std::partition(Types.begin(), Types.end(), isFirstClassType);

  // Now that we rearranged the type table, rebuild TypeMap.
  for (unsigned i = 0, e = Types.size(); i != e; ++i)
    TypeMap[Types[i].first] = i+1;
}
예제 #20
0
/// NaClValueEnumerator - Enumerate module-level information.
NaClValueEnumerator::NaClValueEnumerator(const Module *M) {
  // Create map for counting frequency of types, and set field
  // TypeCountMap accordingly.  Note: Pointer field TypeCountMap is
  // used to deal with the fact that types are added through various
  // method calls in this routine. Rather than pass it as an argument,
  // we use a field. The field is a pointer so that the memory
  // footprint of count_map can be garbage collected when this
  // constructor completes.
  TypeCountMapType count_map;
  TypeCountMap = &count_map;
  // 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);
        }
      }
  }

  // Optimized type indicies to put "common" expected types in with small
  // indices.
  OptimizeTypes(M);
  TypeCountMap = NULL;

  // Optimize constant ordering.
  OptimizeConstants(FirstConstant, Values.size());
}
예제 #21
0
void TypeFinder::run(const Module &M, bool onlyNamed) {
    OnlyNamed = onlyNamed;

    // Get types from global variables.
    for (Module::const_global_iterator I = M.global_begin(),
            E = M.global_end(); I != E; ++I) {
        incorporateType(I->getType());
        if (I->hasInitializer())
            incorporateValue(I->getInitializer());
    }

    // Get types from aliases.
    for (Module::const_alias_iterator I = M.alias_begin(),
            E = M.alias_end(); I != E; ++I) {
        incorporateType(I->getType());
        if (const Value *Aliasee = I->getAliasee())
            incorporateValue(Aliasee);
    }

    // Get types from functions.
    SmallVector<std::pair<unsigned, MDNode *>, 4> MDForInst;
    for (Module::const_iterator FI = M.begin(), E = M.end(); FI != E; ++FI) {
        incorporateType(FI->getType());

        if (FI->hasPrefixData())
            incorporateValue(FI->getPrefixData());

        if (FI->hasPrologueData())
            incorporateValue(FI->getPrologueData());

        if (FI->hasPersonalityFn())
            incorporateValue(FI->getPersonalityFn());

        // First incorporate the arguments.
        for (Function::const_arg_iterator AI = FI->arg_begin(),
                AE = FI->arg_end(); AI != AE; ++AI)
            incorporateValue(AI);

        for (Function::const_iterator BB = FI->begin(), E = FI->end();
                BB != E; ++BB)
            for (BasicBlock::const_iterator II = BB->begin(),
                    E = BB->end(); II != E; ++II) {
                const Instruction &I = *II;

                // Incorporate the type of the instruction.
                incorporateType(I.getType());

                // Incorporate non-instruction operand types. (We are incorporating all
                // instructions with this loop.)
                for (User::const_op_iterator OI = I.op_begin(), OE = I.op_end();
                        OI != OE; ++OI)
                    if (*OI && !isa<Instruction>(OI))
                        incorporateValue(*OI);

                // Incorporate types hiding in metadata.
                I.getAllMetadataOtherThanDebugLoc(MDForInst);
                for (unsigned i = 0, e = MDForInst.size(); i != e; ++i)
                    incorporateMDNode(MDForInst[i].second);

                MDForInst.clear();
            }
    }

    for (Module::const_named_metadata_iterator I = M.named_metadata_begin(),
            E = M.named_metadata_end(); I != E; ++I) {
        const NamedMDNode *NMD = I;
        for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i)
            incorporateMDNode(NMD->getOperand(i));
    }
}
void FunctionLoweringInfo::set(const Function &fn, MachineFunction &mf) {
  Fn = &fn;
  MF = &mf;
  RegInfo = &MF->getRegInfo();

  // Create a vreg for each argument register that is not dead and is used
  // outside of the entry block for the function.
  for (Function::const_arg_iterator AI = Fn->arg_begin(), E = Fn->arg_end();
       AI != E; ++AI)
    if (!isOnlyUsedInEntryBlock(AI, EnableFastISel))
      InitializeRegForValue(AI);

  // 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))
      if (const ConstantInt *CUI = dyn_cast<ConstantInt>(AI->getArraySize())) {
        const Type *Ty = AI->getAllocatedType();
        uint64_t TySize = TLI.getTargetData()->getTypeAllocSize(Ty);
        unsigned Align =
          std::max((unsigned)TLI.getTargetData()->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);
      }

  for (; BB != EB; ++BB)
    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I != E; ++I)
      if (isUsedOutsideOfDefiningBlock(I))
        if (!isa<AllocaInst>(I) ||
            !StaticAllocaMap.count(cast<AllocaInst>(I)))
          InitializeRegForValue(I);

  // 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;

      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->getTarget().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();
}
/// NaClValueEnumerator - Enumerate module-level information.
NaClValueEnumerator::NaClValueEnumerator(const Module *M) {
  // Create map for counting frequency of types, and set field
  // TypeCountMap accordingly.  Note: Pointer field TypeCountMap is
  // used to deal with the fact that types are added through various
  // method calls in this routine. Rather than pass it as an argument,
  // we use a field. The field is a pointer so that the memory
  // footprint of count_map can be garbage collected when this
  // constructor completes.
  TypeCountMapType count_map;
  TypeCountMap = &count_map;

  IntPtrType = IntegerType::get(M->getContext(), PNaClIntPtrTypeBitSize);

  // Enumerate the functions. Note: We do this before global
  // variables, so that global variable initializations can refer to
  // the functions without a forward reference.
  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I) {
    EnumerateValue(I);
  }

  // Enumerate the global variables.
  FirstGlobalVarID = Values.size();
  for (Module::const_global_iterator I = M->global_begin(),
         E = M->global_end(); I != E; ++I)
    EnumerateValue(I);
  NumGlobalVarIDs = Values.size() - FirstGlobalVarID;

  // 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();

  // Skip global variable initializers since they are handled within
  // WriteGlobalVars of file NaClBitcodeWriter.cpp.

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

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

  // 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){
        // Don't generate types for elided pointer casts!
        if (IsElidedCast(I))
          continue;

        if (const SwitchInst *SI = dyn_cast<SwitchInst>(I)) {
          // Handle switch instruction specially, so that we don't
          // write out unnecessary vector/array types used to model case
          // selectors.
          EnumerateOperandType(SI->getCondition());
        } else {
          for (User::const_op_iterator OI = I->op_begin(), E = I->op_end();
               OI != E; ++OI) {
            EnumerateOperandType(*OI);
          }
        }
        EnumerateType(I->getType());
      }
  }

  // Optimized type indicies to put "common" expected types in with small
  // indices.
  OptimizeTypes(M);
  TypeCountMap = NULL;

  // Optimize constant ordering.
  OptimizeConstants(FirstConstant, Values.size());
}
예제 #24
0
void FunctionLoweringInfo::set(const Function &fn, MachineFunction &mf,
                               SelectionDAG *DAG) {
    const TargetLowering *TLI = TM.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.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->getTarget().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();
}
예제 #25
0
/// InlineFunction - This function inlines the called function into the basic
/// block of the caller.  This returns false if it is not possible to inline
/// this call.  The program is still in a well defined state if this occurs
/// though.
///
/// Note that this only does one level of inlining.  For example, if the
/// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now
/// exists in the instruction stream.  Similarly this will inline a recursive
/// function by one level.
bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
                          bool InsertLifetime) {
  Instruction *TheCall = CS.getInstruction();
  assert(TheCall->getParent() && TheCall->getParent()->getParent() &&
         "Instruction not in function!");

  // If IFI has any state in it, zap it before we fill it in.
  IFI.reset();
  
  const Function *CalledFunc = CS.getCalledFunction();
  if (CalledFunc == 0 ||          // Can't inline external function or indirect
      CalledFunc->isDeclaration() || // call, or call to a vararg function!
      CalledFunc->getFunctionType()->isVarArg()) return false;

  // If the call to the callee is not a tail call, we must clear the 'tail'
  // flags on any calls that we inline.
  bool MustClearTailCallFlags =
    !(isa<CallInst>(TheCall) && cast<CallInst>(TheCall)->isTailCall());

  // If the call to the callee cannot throw, set the 'nounwind' flag on any
  // calls that we inline.
  bool MarkNoUnwind = CS.doesNotThrow();

  BasicBlock *OrigBB = TheCall->getParent();
  Function *Caller = OrigBB->getParent();

  // GC poses two hazards to inlining, which only occur when the callee has GC:
  //  1. If the caller has no GC, then the callee's GC must be propagated to the
  //     caller.
  //  2. If the caller has a differing GC, it is invalid to inline.
  if (CalledFunc->hasGC()) {
    if (!Caller->hasGC())
      Caller->setGC(CalledFunc->getGC());
    else if (CalledFunc->getGC() != Caller->getGC())
      return false;
  }

  // Get the personality function from the callee if it contains a landing pad.
  Value *CalleePersonality = 0;
  for (Function::const_iterator I = CalledFunc->begin(), E = CalledFunc->end();
       I != E; ++I)
    if (const InvokeInst *II = dyn_cast<InvokeInst>(I->getTerminator())) {
      const BasicBlock *BB = II->getUnwindDest();
      const LandingPadInst *LP = BB->getLandingPadInst();
      CalleePersonality = LP->getPersonalityFn();
      break;
    }

  // Find the personality function used by the landing pads of the caller. If it
  // exists, then check to see that it matches the personality function used in
  // the callee.
  if (CalleePersonality) {
    for (Function::const_iterator I = Caller->begin(), E = Caller->end();
         I != E; ++I)
      if (const InvokeInst *II = dyn_cast<InvokeInst>(I->getTerminator())) {
        const BasicBlock *BB = II->getUnwindDest();
        const LandingPadInst *LP = BB->getLandingPadInst();

        // If the personality functions match, then we can perform the
        // inlining. Otherwise, we can't inline.
        // TODO: This isn't 100% true. Some personality functions are proper
        //       supersets of others and can be used in place of the other.
        if (LP->getPersonalityFn() != CalleePersonality)
          return false;

        break;
      }
  }

  // Get an iterator to the last basic block in the function, which will have
  // the new function inlined after it.
  Function::iterator LastBlock = &Caller->back();

  // Make sure to capture all of the return instructions from the cloned
  // function.
  SmallVector<ReturnInst*, 8> Returns;
  ClonedCodeInfo InlinedFunctionInfo;
  Function::iterator FirstNewBlock;

  { // Scope to destroy VMap after cloning.
    ValueToValueMapTy VMap;

    assert(CalledFunc->arg_size() == CS.arg_size() &&
           "No varargs calls can be inlined!");

    // Calculate the vector of arguments to pass into the function cloner, which
    // matches up the formal to the actual argument values.
    CallSite::arg_iterator AI = CS.arg_begin();
    unsigned ArgNo = 0;
    for (Function::const_arg_iterator I = CalledFunc->arg_begin(),
         E = CalledFunc->arg_end(); I != E; ++I, ++AI, ++ArgNo) {
      Value *ActualArg = *AI;
      const Argument *Arg = I;

      // When byval arguments actually inlined, we need to make the copy implied
      // by them explicit.  However, we don't do this if the callee is readonly
      // or readnone, because the copy would be unneeded: the callee doesn't
      // modify the struct.
      if (CS.isByValArgument(ArgNo)) {
        ActualArg = HandleByValArgument(ActualArg, Arg, TheCall, CalledFunc, IFI,
                                        CalledFunc->getParamAlignment(ArgNo+1));
 
        // Calls that we inline may use the new alloca, so we need to clear
        // their 'tail' flags if HandleByValArgument introduced a new alloca and
        // the callee has calls.
        MustClearTailCallFlags |= ActualArg != *AI;
      }

      VMap[I] = ActualArg;
    }

    // We want the inliner to prune the code as it copies.  We would LOVE to
    // have no dead or constant instructions leftover after inlining occurs
    // (which can happen, e.g., because an argument was constant), but we'll be
    // happy with whatever the cloner can do.
    CloneAndPruneFunctionInto(Caller, CalledFunc, VMap, 
                              /*ModuleLevelChanges=*/false, Returns, ".i",
                              &InlinedFunctionInfo, IFI.TD, TheCall);

    // Remember the first block that is newly cloned over.
    FirstNewBlock = LastBlock; ++FirstNewBlock;

    // Update the callgraph if requested.
    if (IFI.CG)
      UpdateCallGraphAfterInlining(CS, FirstNewBlock, VMap, IFI);

    // Update inlined instructions' line number information.
    fixupLineNumbers(Caller, FirstNewBlock, TheCall);
  }

  // If there are any alloca instructions in the block that used to be the entry
  // block for the callee, move them to the entry block of the caller.  First
  // calculate which instruction they should be inserted before.  We insert the
  // instructions at the end of the current alloca list.
  {
    BasicBlock::iterator InsertPoint = Caller->begin()->begin();
    for (BasicBlock::iterator I = FirstNewBlock->begin(),
         E = FirstNewBlock->end(); I != E; ) {
      AllocaInst *AI = dyn_cast<AllocaInst>(I++);
      if (AI == 0) continue;
      
      // If the alloca is now dead, remove it.  This often occurs due to code
      // specialization.
      if (AI->use_empty()) {
        AI->eraseFromParent();
        continue;
      }

      if (!isa<Constant>(AI->getArraySize()))
        continue;
      
      // Keep track of the static allocas that we inline into the caller.
      IFI.StaticAllocas.push_back(AI);
      
      // Scan for the block of allocas that we can move over, and move them
      // all at once.
      while (isa<AllocaInst>(I) &&
             isa<Constant>(cast<AllocaInst>(I)->getArraySize())) {
        IFI.StaticAllocas.push_back(cast<AllocaInst>(I));
        ++I;
      }

      // Transfer all of the allocas over in a block.  Using splice means
      // that the instructions aren't removed from the symbol table, then
      // reinserted.
      Caller->getEntryBlock().getInstList().splice(InsertPoint,
                                                   FirstNewBlock->getInstList(),
                                                   AI, I);
    }
  }

  // Leave lifetime markers for the static alloca's, scoping them to the
  // function we just inlined.
  if (InsertLifetime && !IFI.StaticAllocas.empty()) {
    IRBuilder<> builder(FirstNewBlock->begin());
    for (unsigned ai = 0, ae = IFI.StaticAllocas.size(); ai != ae; ++ai) {
      AllocaInst *AI = IFI.StaticAllocas[ai];

      // If the alloca is already scoped to something smaller than the whole
      // function then there's no need to add redundant, less accurate markers.
      if (hasLifetimeMarkers(AI))
        continue;

      // Try to determine the size of the allocation.
      ConstantInt *AllocaSize = 0;
      if (ConstantInt *AIArraySize =
          dyn_cast<ConstantInt>(AI->getArraySize())) {
        if (IFI.TD) {
          Type *AllocaType = AI->getAllocatedType();
          uint64_t AllocaTypeSize = IFI.TD->getTypeAllocSize(AllocaType);
          uint64_t AllocaArraySize = AIArraySize->getLimitedValue();
          assert(AllocaArraySize > 0 && "array size of AllocaInst is zero");
          // Check that array size doesn't saturate uint64_t and doesn't
          // overflow when it's multiplied by type size.
          if (AllocaArraySize != ~0ULL &&
              UINT64_MAX / AllocaArraySize >= AllocaTypeSize) {
            AllocaSize = ConstantInt::get(Type::getInt64Ty(AI->getContext()),
                                          AllocaArraySize * AllocaTypeSize);
          }
        }
      }

      builder.CreateLifetimeStart(AI, AllocaSize);
      for (unsigned ri = 0, re = Returns.size(); ri != re; ++ri) {
        IRBuilder<> builder(Returns[ri]);
        builder.CreateLifetimeEnd(AI, AllocaSize);
      }
    }
  }

  // If the inlined code contained dynamic alloca instructions, wrap the inlined
  // code with llvm.stacksave/llvm.stackrestore intrinsics.
  if (InlinedFunctionInfo.ContainsDynamicAllocas) {
    Module *M = Caller->getParent();
    // Get the two intrinsics we care about.
    Function *StackSave = Intrinsic::getDeclaration(M, Intrinsic::stacksave);
    Function *StackRestore=Intrinsic::getDeclaration(M,Intrinsic::stackrestore);

    // Insert the llvm.stacksave.
    CallInst *SavedPtr = IRBuilder<>(FirstNewBlock, FirstNewBlock->begin())
      .CreateCall(StackSave, "savedstack");

    // Insert a call to llvm.stackrestore before any return instructions in the
    // inlined function.
    for (unsigned i = 0, e = Returns.size(); i != e; ++i) {
      IRBuilder<>(Returns[i]).CreateCall(StackRestore, SavedPtr);
    }
  }

  // If we are inlining tail call instruction through a call site that isn't
  // marked 'tail', we must remove the tail marker for any calls in the inlined
  // code.  Also, calls inlined through a 'nounwind' call site should be marked
  // 'nounwind'.
  if (InlinedFunctionInfo.ContainsCalls &&
      (MustClearTailCallFlags || MarkNoUnwind)) {
    for (Function::iterator BB = FirstNewBlock, E = Caller->end();
         BB != E; ++BB)
      for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
        if (CallInst *CI = dyn_cast<CallInst>(I)) {
          if (MustClearTailCallFlags)
            CI->setTailCall(false);
          if (MarkNoUnwind)
            CI->setDoesNotThrow();
        }
  }

  // If we are inlining for an invoke instruction, we must make sure to rewrite
  // any call instructions into invoke instructions.
  if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall))
    HandleInlinedInvoke(II, FirstNewBlock, InlinedFunctionInfo);

  // If we cloned in _exactly one_ basic block, and if that block ends in a
  // return instruction, we splice the body of the inlined callee directly into
  // the calling basic block.
  if (Returns.size() == 1 && std::distance(FirstNewBlock, Caller->end()) == 1) {
    // Move all of the instructions right before the call.
    OrigBB->getInstList().splice(TheCall, FirstNewBlock->getInstList(),
                                 FirstNewBlock->begin(), FirstNewBlock->end());
    // Remove the cloned basic block.
    Caller->getBasicBlockList().pop_back();

    // If the call site was an invoke instruction, add a branch to the normal
    // destination.
    if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) {
      BranchInst *NewBr = BranchInst::Create(II->getNormalDest(), TheCall);
      NewBr->setDebugLoc(Returns[0]->getDebugLoc());
    }

    // If the return instruction returned a value, replace uses of the call with
    // uses of the returned value.
    if (!TheCall->use_empty()) {
      ReturnInst *R = Returns[0];
      if (TheCall == R->getReturnValue())
        TheCall->replaceAllUsesWith(UndefValue::get(TheCall->getType()));
      else
        TheCall->replaceAllUsesWith(R->getReturnValue());
    }
    // Since we are now done with the Call/Invoke, we can delete it.
    TheCall->eraseFromParent();

    // Since we are now done with the return instruction, delete it also.
    Returns[0]->eraseFromParent();

    // We are now done with the inlining.
    return true;
  }

  // Otherwise, we have the normal case, of more than one block to inline or
  // multiple return sites.

  // We want to clone the entire callee function into the hole between the
  // "starter" and "ender" blocks.  How we accomplish this depends on whether
  // this is an invoke instruction or a call instruction.
  BasicBlock *AfterCallBB;
  BranchInst *CreatedBranchToNormalDest = NULL;
  if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) {

    // Add an unconditional branch to make this look like the CallInst case...
    CreatedBranchToNormalDest = BranchInst::Create(II->getNormalDest(), TheCall);

    // Split the basic block.  This guarantees that no PHI nodes will have to be
    // updated due to new incoming edges, and make the invoke case more
    // symmetric to the call case.
    AfterCallBB = OrigBB->splitBasicBlock(CreatedBranchToNormalDest,
                                          CalledFunc->getName()+".exit");

  } else {  // It's a call
    // If this is a call instruction, we need to split the basic block that
    // the call lives in.
    //
    AfterCallBB = OrigBB->splitBasicBlock(TheCall,
                                          CalledFunc->getName()+".exit");
  }

  // Change the branch that used to go to AfterCallBB to branch to the first
  // basic block of the inlined function.
  //
  TerminatorInst *Br = OrigBB->getTerminator();
  assert(Br && Br->getOpcode() == Instruction::Br &&
         "splitBasicBlock broken!");
  Br->setOperand(0, FirstNewBlock);


  // Now that the function is correct, make it a little bit nicer.  In
  // particular, move the basic blocks inserted from the end of the function
  // into the space made by splitting the source basic block.
  Caller->getBasicBlockList().splice(AfterCallBB, Caller->getBasicBlockList(),
                                     FirstNewBlock, Caller->end());

  // Handle all of the return instructions that we just cloned in, and eliminate
  // any users of the original call/invoke instruction.
  Type *RTy = CalledFunc->getReturnType();

  PHINode *PHI = 0;
  if (Returns.size() > 1) {
    // The PHI node should go at the front of the new basic block to merge all
    // possible incoming values.
    if (!TheCall->use_empty()) {
      PHI = PHINode::Create(RTy, Returns.size(), TheCall->getName(),
                            AfterCallBB->begin());
      // Anything that used the result of the function call should now use the
      // PHI node as their operand.
      TheCall->replaceAllUsesWith(PHI);
    }

    // Loop over all of the return instructions adding entries to the PHI node
    // as appropriate.
    if (PHI) {
      for (unsigned i = 0, e = Returns.size(); i != e; ++i) {
        ReturnInst *RI = Returns[i];
        assert(RI->getReturnValue()->getType() == PHI->getType() &&
               "Ret value not consistent in function!");
        PHI->addIncoming(RI->getReturnValue(), RI->getParent());
      }
    }


    // Add a branch to the merge points and remove return instructions.
    DebugLoc Loc;
    for (unsigned i = 0, e = Returns.size(); i != e; ++i) {
      ReturnInst *RI = Returns[i];
      BranchInst* BI = BranchInst::Create(AfterCallBB, RI);
      Loc = RI->getDebugLoc();
      BI->setDebugLoc(Loc);
      RI->eraseFromParent();
    }
    // We need to set the debug location to *somewhere* inside the
    // inlined function. The line number may be nonsensical, but the
    // instruction will at least be associated with the right
    // function.
    if (CreatedBranchToNormalDest)
      CreatedBranchToNormalDest->setDebugLoc(Loc);
  } else if (!Returns.empty()) {
    // Otherwise, if there is exactly one return value, just replace anything
    // using the return value of the call with the computed value.
    if (!TheCall->use_empty()) {
      if (TheCall == Returns[0]->getReturnValue())
        TheCall->replaceAllUsesWith(UndefValue::get(TheCall->getType()));
      else
        TheCall->replaceAllUsesWith(Returns[0]->getReturnValue());
    }

    // Update PHI nodes that use the ReturnBB to use the AfterCallBB.
    BasicBlock *ReturnBB = Returns[0]->getParent();
    ReturnBB->replaceAllUsesWith(AfterCallBB);

    // Splice the code from the return block into the block that it will return
    // to, which contains the code that was after the call.
    AfterCallBB->getInstList().splice(AfterCallBB->begin(),
                                      ReturnBB->getInstList());

    if (CreatedBranchToNormalDest)
      CreatedBranchToNormalDest->setDebugLoc(Returns[0]->getDebugLoc());

    // Delete the return instruction now and empty ReturnBB now.
    Returns[0]->eraseFromParent();
    ReturnBB->eraseFromParent();
  } else if (!TheCall->use_empty()) {
    // No returns, but something is using the return value of the call.  Just
    // nuke the result.
    TheCall->replaceAllUsesWith(UndefValue::get(TheCall->getType()));
  }

  // Since we are now done with the Call/Invoke, we can delete it.
  TheCall->eraseFromParent();

  // We should always be able to fold the entry block of the function into the
  // single predecessor of the block...
  assert(cast<BranchInst>(Br)->isUnconditional() && "splitBasicBlock broken!");
  BasicBlock *CalleeEntry = cast<BranchInst>(Br)->getSuccessor(0);

  // Splice the code entry block into calling block, right before the
  // unconditional branch.
  CalleeEntry->replaceAllUsesWith(OrigBB);  // Update PHI nodes
  OrigBB->getInstList().splice(Br, CalleeEntry->getInstList());

  // Remove the unconditional branch.
  OrigBB->getInstList().erase(Br);

  // Now we can remove the CalleeEntry block, which is now empty.
  Caller->getBasicBlockList().erase(CalleeEntry);

  // If we inserted a phi node, check to see if it has a single value (e.g. all
  // the entries are the same or undef).  If so, remove the PHI so it doesn't
  // block other optimizations.
  if (PHI) {
    if (Value *V = SimplifyInstruction(PHI, IFI.TD)) {
      PHI->replaceAllUsesWith(V);
      PHI->eraseFromParent();
    }
  }

  return true;
}
예제 #26
0
/// ValueEnumerator - Enumerate module-level information.
ValueEnumerator::ValueEnumerator(const Module *M) {
  InstructionCount = 0;

  // 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());

  // Enumerate types used by the type symbol table.
  EnumerateTypeSymbolTable(M->getTypeSymbolTable());

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

  // 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());

    MetadataContext &TheMetadata = F->getContext().getMetadata();
    typedef SmallVector<std::pair<unsigned, TrackingVH<MDNode> >, 2> MDMapTy;
    MDMapTy MDs;
    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)
          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();
        TheMetadata.getMDs(I, MDs);
        for (MDMapTy::const_iterator MI = MDs.begin(), ME = MDs.end(); MI != ME;
             ++MI)
          EnumerateMetadata(MI->second);
      }
  }

  // Optimize constant ordering.
  OptimizeConstants(FirstConstant, Values.size());

  // Sort the type table by frequency so that most commonly used types are early
  // in the table (have low bit-width).
  std::stable_sort(Types.begin(), Types.end(), CompareByFrequency);

  // Partition the Type ID's so that the single-value types occur before the
  // aggregate types.  This allows the aggregate types to be dropped from the
  // type table after parsing the global variable initializers.
  std::partition(Types.begin(), Types.end(), isSingleValueType);

  // Now that we rearranged the type table, rebuild TypeMap.
  for (unsigned i = 0, e = Types.size(); i != e; ++i)
    TypeMap[Types[i].first] = i+1;
}
// SurveyFunction - This performs the initial survey of the specified function,
// checking out whether or not it uses any of its incoming arguments or whether
// any callers use the return value.  This fills in the LiveValues set and Uses
// map.
//
// We consider arguments of non-internal functions to be intrinsically alive as
// well as arguments to functions which have their "address taken".
//
void DAE::SurveyFunction(const Function &F) {
  unsigned RetCount = NumRetVals(&F);
  // Assume all return values are dead
  typedef SmallVector<Liveness, 5> RetVals;
  RetVals RetValLiveness(RetCount, MaybeLive);

  typedef SmallVector<UseVector, 5> RetUses;
  // These vectors map each return value to the uses that make it MaybeLive, so
  // we can add those to the Uses map if the return value really turns out to be
  // MaybeLive. Initialized to a list of RetCount empty lists.
  RetUses MaybeLiveRetUses(RetCount);

  for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
    if (const ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator()))
      if (RI->getNumOperands() != 0 && RI->getOperand(0)->getType()
          != F.getFunctionType()->getReturnType()) {
        // We don't support old style multiple return values.
        MarkLive(F);
        return;
      }

  if (!F.hasLocalLinkage() && (!ShouldHackArguments() || F.isIntrinsic())) {
    MarkLive(F);
    return;
  }

  DEBUG(dbgs() << "DAE - Inspecting callers for fn: " << F.getName() << "\n");
  // Keep track of the number of live retvals, so we can skip checks once all
  // of them turn out to be live.
  unsigned NumLiveRetVals = 0;
  Type *STy = dyn_cast<StructType>(F.getReturnType());
  // Loop all uses of the function.
  for (Value::const_use_iterator I = F.use_begin(), E = F.use_end();
       I != E; ++I) {
    // If the function is PASSED IN as an argument, its address has been
    // taken.
    ImmutableCallSite CS(*I);
    if (!CS || !CS.isCallee(I)) {
      MarkLive(F);
      return;
    }

    // If this use is anything other than a call site, the function is alive.
    const Instruction *TheCall = CS.getInstruction();
    if (!TheCall) {   // Not a direct call site?
      MarkLive(F);
      return;
    }

    // If we end up here, we are looking at a direct call to our function.

    // Now, check how our return value(s) is/are used in this caller. Don't
    // bother checking return values if all of them are live already.
    if (NumLiveRetVals != RetCount) {
      if (STy) {
        // Check all uses of the return value.
        for (Value::const_use_iterator I = TheCall->use_begin(),
             E = TheCall->use_end(); I != E; ++I) {
          const ExtractValueInst *Ext = dyn_cast<ExtractValueInst>(*I);
          if (Ext && Ext->hasIndices()) {
            // This use uses a part of our return value, survey the uses of
            // that part and store the results for this index only.
            unsigned Idx = *Ext->idx_begin();
            if (RetValLiveness[Idx] != Live) {
              RetValLiveness[Idx] = SurveyUses(Ext, MaybeLiveRetUses[Idx]);
              if (RetValLiveness[Idx] == Live)
                NumLiveRetVals++;
            }
          } else {
            // Used by something else than extractvalue. Mark all return
            // values as live.
            for (unsigned i = 0; i != RetCount; ++i )
              RetValLiveness[i] = Live;
            NumLiveRetVals = RetCount;
            break;
          }
        }
      } else {
        // Single return value
        RetValLiveness[0] = SurveyUses(TheCall, MaybeLiveRetUses[0]);
        if (RetValLiveness[0] == Live)
          NumLiveRetVals = RetCount;
      }
    }
  }

  // Now we've inspected all callers, record the liveness of our return values.
  for (unsigned i = 0; i != RetCount; ++i)
    MarkValue(CreateRet(&F, i), RetValLiveness[i], MaybeLiveRetUses[i]);

  DEBUG(dbgs() << "DAE - Inspecting args for fn: " << F.getName() << "\n");

  // Now, check all of our arguments.
  unsigned i = 0;
  UseVector MaybeLiveArgUses;
  for (Function::const_arg_iterator AI = F.arg_begin(),
       E = F.arg_end(); AI != E; ++AI, ++i) {
    // See what the effect of this use is (recording any uses that cause
    // MaybeLive in MaybeLiveArgUses).
    Liveness Result = SurveyUses(AI, MaybeLiveArgUses);
    // Mark the result.
    MarkValue(CreateArg(&F, i), Result, MaybeLiveArgUses);
    // Clear the vector again for the next iteration.
    MaybeLiveArgUses.clear();
  }
}
예제 #28
0
void FunctionLoweringInfo::set(const Function &fn, MachineFunction &mf,
                               SelectionDAG *DAG) {
  Fn = &fn;
  MF = &mf;
  TLI = MF->getSubtarget().getTargetLowering();
  RegInfo = &MF->getRegInfo();
  MachineModuleInfo &MMI = MF->getMMI();
  const TargetFrameLowering *TFI = MF->getSubtarget().getFrameLowering();
  unsigned StackAlign = TFI->getStackAlignment();

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

  // If this personality uses funclets, we need to do a bit more work.
  DenseMap<const AllocaInst *, int *> CatchObjects;
  EHPersonality Personality = classifyEHPersonality(
      Fn->hasPersonalityFn() ? Fn->getPersonalityFn() : nullptr);
  if (isFuncletEHPersonality(Personality)) {
    // Calculate state numbers if we haven't already.
    WinEHFuncInfo &EHInfo = *MF->getWinEHFuncInfo();
    if (Personality == EHPersonality::MSVC_CXX)
      calculateWinCXXEHStateNumbers(&fn, EHInfo);
    else if (isAsynchronousEHPersonality(Personality))
      calculateSEHStateNumbers(&fn, EHInfo);
    else if (Personality == EHPersonality::CoreCLR)
      calculateClrEHStateNumbers(&fn, EHInfo);

    // Map all BB references in the WinEH data to MBBs.
    for (WinEHTryBlockMapEntry &TBME : EHInfo.TryBlockMap) {
      for (WinEHHandlerType &H : TBME.HandlerArray) {
        if (const AllocaInst *AI = H.CatchObj.Alloca)
          CatchObjects.insert({AI, &H.CatchObj.FrameIndex});
        else
          H.CatchObj.FrameIndex = INT_MAX;
      }
    }
  }

  // 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 (; BB != EB; ++BB)
    for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
         I != E; ++I) {
      if (const AllocaInst *AI = dyn_cast<AllocaInst>(I)) {
        Type *Ty = AI->getAllocatedType();
        unsigned Align =
          std::max((unsigned)MF->getDataLayout().getPrefTypeAlignment(Ty),
                   AI->getAlignment());

        // Static allocas can be folded into the initial stack frame
        // adjustment. For targets that don't realign the stack, don't
        // do this if there is an extra alignment requirement.
        if (AI->isStaticAlloca() && 
            (TFI->isStackRealignable() || (Align <= StackAlign))) {
          const ConstantInt *CUI = cast<ConstantInt>(AI->getArraySize());
          uint64_t TySize = MF->getDataLayout().getTypeAllocSize(Ty);

          TySize *= CUI->getZExtValue();   // Get total allocated size.
          if (TySize == 0) TySize = 1; // Don't create zero-sized stack objects.
          int FrameIndex = INT_MAX;
          auto Iter = CatchObjects.find(AI);
          if (Iter != CatchObjects.end() && TLI->needsFixedCatchObjects()) {
            FrameIndex = MF->getFrameInfo().CreateFixedObject(
                TySize, 0, /*Immutable=*/false, /*isAliased=*/true);
            MF->getFrameInfo().setObjectAlignment(FrameIndex, Align);
          } else {
            FrameIndex =
                MF->getFrameInfo().CreateStackObject(TySize, Align, false, AI);
          }

          StaticAllocaMap[AI] = FrameIndex;
          // Update the catch handler information.
          if (Iter != CatchObjects.end())
            *Iter->second = FrameIndex;
        } else {
          // FIXME: Overaligned static allocas should be grouped into
          // a single dynamic allocation instead of using a separate
          // stack allocation for each one.
          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();
          const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
          std::vector<TargetLowering::AsmOperandInfo> Ops =
              TLI->ParseConstraints(Fn->getParent()->getDataLayout(), TRI, 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(TRI, Op.ConstraintCode,
                                                    Op.ConstraintVT);
              if (PhysReg.first == SP)
                MF->getFrameInfo().setHasOpaqueSPAdjustment(true);
            }
          }
        }
      }

      // Look for calls to the @llvm.va_start intrinsic. We can omit some
      // prologue boilerplate for variadic functions that don't examine their
      // arguments.
      if (const auto *II = dyn_cast<IntrinsicInst>(I)) {
        if (II->getIntrinsicID() == Intrinsic::vastart)
          MF->getFrameInfo().setHasVAStart(true);
      }

      // If we have a musttail call in a variadic function, we need to ensure we
      // forward implicit register parameters.
      if (const auto *CI = dyn_cast<CallInst>(I)) {
        if (CI->isMustTailCall() && Fn->isVarArg())
          MF->getFrameInfo().setHasMustTailInVarArgFunc(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)) {
        assert(DI->getVariable() && "Missing variable");
        assert(DI->getDebugLoc() && "Missing location");
        if (MMI.hasDebugInfo()) {
          // 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(), DI->getExpression(),
                                       FI, DI->getDebugLoc());
              }
            }
          }
        }
      }

      // Decide the preferred extend type for a value.
      PreferredExtendType[&*I] = getPreferredExtendForValue(&*I);
    }

  // 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) {
    // Don't create MachineBasicBlocks for imaginary EH pad blocks. These blocks
    // are really data, and no instructions can live here.
    if (BB->isEHPad()) {
      const Instruction *I = BB->getFirstNonPHI();
      // If this is a non-landingpad EH pad, mark this function as using
      // funclets.
      // FIXME: SEH catchpads do not create funclets, so we could avoid setting
      // this in such cases in order to improve frame layout.
      if (!isa<LandingPadInst>(I)) {
        MMI.setHasEHFunclets(true);
        MF->getFrameInfo().setHasOpaqueSPAdjustment(true);
      }
      if (isa<CatchSwitchInst>(I)) {
        assert(&*BB->begin() == I &&
               "WinEHPrepare failed to remove PHIs from imaginary BBs");
        continue;
      }
      if (isa<FuncletPadInst>(I))
        assert(&*BB->begin() == I && "WinEHPrepare failed to demote PHIs");
    }

    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, MF->getDataLayout(), 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.
  SmallVector<const LandingPadInst *, 4> LPads;
  for (BB = Fn->begin(); BB != EB; ++BB) {
    const Instruction *FNP = BB->getFirstNonPHI();
    if (BB->isEHPad() && MBBMap.count(&*BB))
      MBBMap[&*BB]->setIsEHPad();
    if (const auto *LPI = dyn_cast<LandingPadInst>(FNP))
      LPads.push_back(LPI);
  }

  if (!isFuncletEHPersonality(Personality))
    return;

  WinEHFuncInfo &EHInfo = *MF->getWinEHFuncInfo();

  // Map all BB references in the WinEH data to MBBs.
  for (WinEHTryBlockMapEntry &TBME : EHInfo.TryBlockMap) {
    for (WinEHHandlerType &H : TBME.HandlerArray) {
      if (H.Handler)
        H.Handler = MBBMap[H.Handler.get<const BasicBlock *>()];
    }
  }
  for (CxxUnwindMapEntry &UME : EHInfo.CxxUnwindMap)
    if (UME.Cleanup)
      UME.Cleanup = MBBMap[UME.Cleanup.get<const BasicBlock *>()];
  for (SEHUnwindMapEntry &UME : EHInfo.SEHUnwindMap) {
    const BasicBlock *BB = UME.Handler.get<const BasicBlock *>();
    UME.Handler = MBBMap[BB];
  }
  for (ClrEHUnwindMapEntry &CME : EHInfo.ClrEHUnwindMap) {
    const BasicBlock *BB = CME.Handler.get<const BasicBlock *>();
    CME.Handler = MBBMap[BB];
  }
}
// SurveyFunction - This performs the initial survey of the specified function,
// checking out whether or not it uses any of its incoming arguments or whether
// any callers use the return value.  This fills in the LiveValues set and Uses
// map.
//
// We consider arguments of non-internal functions to be intrinsically alive as
// well as arguments to functions which have their "address taken".
//
void DAE::SurveyFunction(const Function &F) {
  // Functions with inalloca parameters are expecting args in a particular
  // register and memory layout.
  if (F.getAttributes().hasAttrSomewhere(Attribute::InAlloca)) {
    MarkLive(F);
    return;
  }

  // Don't touch naked functions. The assembly might be using an argument, or
  // otherwise rely on the frame layout in a way that this analysis will not
  // see.
  if (F.hasFnAttribute(Attribute::Naked)) {
    MarkLive(F);
    return;
  }

  unsigned RetCount = NumRetVals(&F);
  // Assume all return values are dead
  typedef SmallVector<Liveness, 5> RetVals;
  RetVals RetValLiveness(RetCount, MaybeLive);

  typedef SmallVector<UseVector, 5> RetUses;
  // These vectors map each return value to the uses that make it MaybeLive, so
  // we can add those to the Uses map if the return value really turns out to be
  // MaybeLive. Initialized to a list of RetCount empty lists.
  RetUses MaybeLiveRetUses(RetCount);

  for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
    if (const ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator()))
      if (RI->getNumOperands() != 0 && RI->getOperand(0)->getType()
          != F.getFunctionType()->getReturnType()) {
        // We don't support old style multiple return values.
        MarkLive(F);
        return;
      }

  if (!F.hasLocalLinkage() && (!ShouldHackArguments() || F.isIntrinsic())) {
    MarkLive(F);
    return;
  }

  DEBUG(dbgs() << "DAE - Inspecting callers for fn: " << F.getName() << "\n");
  // Keep track of the number of live retvals, so we can skip checks once all
  // of them turn out to be live.
  unsigned NumLiveRetVals = 0;
  // Loop all uses of the function.
  for (const Use &U : F.uses()) {
    // If the function is PASSED IN as an argument, its address has been
    // taken.
    ImmutableCallSite CS(U.getUser());
    if (!CS || !CS.isCallee(&U)) {
      MarkLive(F);
      return;
    }

    // If this use is anything other than a call site, the function is alive.
    const Instruction *TheCall = CS.getInstruction();
    if (!TheCall) {   // Not a direct call site?
      MarkLive(F);
      return;
    }

    // If we end up here, we are looking at a direct call to our function.

    // Now, check how our return value(s) is/are used in this caller. Don't
    // bother checking return values if all of them are live already.
    if (NumLiveRetVals == RetCount)
      continue;

    // Check all uses of the return value.
    for (const Use &U : TheCall->uses()) {
      if (ExtractValueInst *Ext = dyn_cast<ExtractValueInst>(U.getUser())) {
        // This use uses a part of our return value, survey the uses of
        // that part and store the results for this index only.
        unsigned Idx = *Ext->idx_begin();
        if (RetValLiveness[Idx] != Live) {
          RetValLiveness[Idx] = SurveyUses(Ext, MaybeLiveRetUses[Idx]);
          if (RetValLiveness[Idx] == Live)
            NumLiveRetVals++;
        }
      } else {
        // Used by something else than extractvalue. Survey, but assume that the
        // result applies to all sub-values.
        UseVector MaybeLiveAggregateUses;
        if (SurveyUse(&U, MaybeLiveAggregateUses) == Live) {
          NumLiveRetVals = RetCount;
          RetValLiveness.assign(RetCount, Live);
          break;
        } else {
          for (unsigned i = 0; i != RetCount; ++i) {
            if (RetValLiveness[i] != Live)
              MaybeLiveRetUses[i].append(MaybeLiveAggregateUses.begin(),
                                         MaybeLiveAggregateUses.end());
          }
        }
      }
    }
  }

  // Now we've inspected all callers, record the liveness of our return values.
  for (unsigned i = 0; i != RetCount; ++i)
    MarkValue(CreateRet(&F, i), RetValLiveness[i], MaybeLiveRetUses[i]);

  DEBUG(dbgs() << "DAE - Inspecting args for fn: " << F.getName() << "\n");

  // Now, check all of our arguments.
  unsigned i = 0;
  UseVector MaybeLiveArgUses;
  for (Function::const_arg_iterator AI = F.arg_begin(),
       E = F.arg_end(); AI != E; ++AI, ++i) {
    Liveness Result;
    if (F.getFunctionType()->isVarArg()) {
      // Variadic functions will already have a va_arg function expanded inside
      // them, making them potentially very sensitive to ABI changes resulting
      // from removing arguments entirely, so don't. For example AArch64 handles
      // register and stack HFAs very differently, and this is reflected in the
      // IR which has already been generated.
      Result = Live;
    } else {
      // See what the effect of this use is (recording any uses that cause
      // MaybeLive in MaybeLiveArgUses). 
      Result = SurveyUses(&*AI, MaybeLiveArgUses);
    }

    // Mark the result.
    MarkValue(CreateArg(&F, i), Result, MaybeLiveArgUses);
    // Clear the vector again for the next iteration.
    MaybeLiveArgUses.clear();
  }
}
예제 #30
0
/// CloneAndPruneFunctionInto - This works exactly like CloneFunctionInto,
/// except that it does some simple constant prop and DCE on the fly.  The
/// effect of this is to copy significantly less code in cases where (for
/// example) a function call with constant arguments is inlined, and those
/// constant arguments cause a significant amount of code in the callee to be
/// dead.  Since this doesn't produce an exact copy of the input, it can't be
/// used for things like CloneFunction or CloneModule.
void llvm::CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc,
                                     ValueToValueMapTy &VMap,
                                     bool ModuleLevelChanges,
                                     SmallVectorImpl<ReturnInst*> &Returns,
                                     const char *NameSuffix,
                                     ClonedCodeInfo *CodeInfo,
                                     const DataLayout *DL,
                                     Instruction *TheCall) {
  assert(NameSuffix && "NameSuffix cannot be null!");

#ifndef NDEBUG
  for (Function::const_arg_iterator II = OldFunc->arg_begin(),
       E = OldFunc->arg_end(); II != E; ++II)
    assert(VMap.count(II) && "No mapping from source argument specified!");
#endif

  PruningFunctionCloner PFC(NewFunc, OldFunc, VMap, ModuleLevelChanges,
                            NameSuffix, CodeInfo, DL);

  // Clone the entry block, and anything recursively reachable from it.
  std::vector<const BasicBlock*> CloneWorklist;
  CloneWorklist.push_back(&OldFunc->getEntryBlock());
  while (!CloneWorklist.empty()) {
    const BasicBlock *BB = CloneWorklist.back();
    CloneWorklist.pop_back();
    PFC.CloneBlock(BB, CloneWorklist);
  }

  // Loop over all of the basic blocks in the old function.  If the block was
  // reachable, we have cloned it and the old block is now in the value map:
  // insert it into the new function in the right order.  If not, ignore it.
  //
  // Defer PHI resolution until rest of function is resolved.
  SmallVector<const PHINode*, 16> PHIToResolve;
  for (Function::const_iterator BI = OldFunc->begin(), BE = OldFunc->end();
       BI != BE; ++BI) {
    Value *V = VMap[BI];
    BasicBlock *NewBB = cast_or_null<BasicBlock>(V);
    if (!NewBB) continue;  // Dead block.

    // Add the new block to the new function.
    NewFunc->getBasicBlockList().push_back(NewBB);

    // Handle PHI nodes specially, as we have to remove references to dead
    // blocks.
    for (BasicBlock::const_iterator I = BI->begin(), E = BI->end(); I != E; ++I)
      if (const PHINode *PN = dyn_cast<PHINode>(I))
        PHIToResolve.push_back(PN);
      else
        break;

    // Finally, remap the terminator instructions, as those can't be remapped
    // until all BBs are mapped.
    RemapInstruction(NewBB->getTerminator(), VMap,
                     ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges);
  }

  // Defer PHI resolution until rest of function is resolved, PHI resolution
  // requires the CFG to be up-to-date.
  for (unsigned phino = 0, e = PHIToResolve.size(); phino != e; ) {
    const PHINode *OPN = PHIToResolve[phino];
    unsigned NumPreds = OPN->getNumIncomingValues();
    const BasicBlock *OldBB = OPN->getParent();
    BasicBlock *NewBB = cast<BasicBlock>(VMap[OldBB]);

    // Map operands for blocks that are live and remove operands for blocks
    // that are dead.
    for (; phino != PHIToResolve.size() &&
         PHIToResolve[phino]->getParent() == OldBB; ++phino) {
      OPN = PHIToResolve[phino];
      PHINode *PN = cast<PHINode>(VMap[OPN]);
      for (unsigned pred = 0, e = NumPreds; pred != e; ++pred) {
        Value *V = VMap[PN->getIncomingBlock(pred)];
        if (BasicBlock *MappedBlock = cast_or_null<BasicBlock>(V)) {
          Value *InVal = MapValue(PN->getIncomingValue(pred),
                                  VMap,
                        ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges);
          assert(InVal && "Unknown input value?");
          PN->setIncomingValue(pred, InVal);
          PN->setIncomingBlock(pred, MappedBlock);
        } else {
          PN->removeIncomingValue(pred, false);
          --pred, --e;  // Revisit the next entry.
        }
      }
    }

    // The loop above has removed PHI entries for those blocks that are dead
    // and has updated others.  However, if a block is live (i.e. copied over)
    // but its terminator has been changed to not go to this block, then our
    // phi nodes will have invalid entries.  Update the PHI nodes in this
    // case.
    PHINode *PN = cast<PHINode>(NewBB->begin());
    NumPreds = std::distance(pred_begin(NewBB), pred_end(NewBB));
    if (NumPreds != PN->getNumIncomingValues()) {
      assert(NumPreds < PN->getNumIncomingValues());
      // Count how many times each predecessor comes to this block.
      std::map<BasicBlock*, unsigned> PredCount;
      for (pred_iterator PI = pred_begin(NewBB), E = pred_end(NewBB);
           PI != E; ++PI)
        --PredCount[*PI];

      // Figure out how many entries to remove from each PHI.
      for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
        ++PredCount[PN->getIncomingBlock(i)];

      // At this point, the excess predecessor entries are positive in the
      // map.  Loop over all of the PHIs and remove excess predecessor
      // entries.
      BasicBlock::iterator I = NewBB->begin();
      for (; (PN = dyn_cast<PHINode>(I)); ++I) {
        for (std::map<BasicBlock*, unsigned>::iterator PCI =PredCount.begin(),
             E = PredCount.end(); PCI != E; ++PCI) {
          BasicBlock *Pred     = PCI->first;
          for (unsigned NumToRemove = PCI->second; NumToRemove; --NumToRemove)
            PN->removeIncomingValue(Pred, false);
        }
      }
    }

    // If the loops above have made these phi nodes have 0 or 1 operand,
    // replace them with undef or the input value.  We must do this for
    // correctness, because 0-operand phis are not valid.
    PN = cast<PHINode>(NewBB->begin());
    if (PN->getNumIncomingValues() == 0) {
      BasicBlock::iterator I = NewBB->begin();
      BasicBlock::const_iterator OldI = OldBB->begin();
      while ((PN = dyn_cast<PHINode>(I++))) {
        Value *NV = UndefValue::get(PN->getType());
        PN->replaceAllUsesWith(NV);
        assert(VMap[OldI] == PN && "VMap mismatch");
        VMap[OldI] = NV;
        PN->eraseFromParent();
        ++OldI;
      }
    }
  }

  // Make a second pass over the PHINodes now that all of them have been
  // remapped into the new function, simplifying the PHINode and performing any
  // recursive simplifications exposed. This will transparently update the
  // WeakVH in the VMap. Notably, we rely on that so that if we coalesce
  // two PHINodes, the iteration over the old PHIs remains valid, and the
  // mapping will just map us to the new node (which may not even be a PHI
  // node).
  for (unsigned Idx = 0, Size = PHIToResolve.size(); Idx != Size; ++Idx)
    if (PHINode *PN = dyn_cast<PHINode>(VMap[PHIToResolve[Idx]]))
      recursivelySimplifyInstruction(PN, DL);

  // Now that the inlined function body has been fully constructed, go through
  // and zap unconditional fall-through branches.  This happen all the time when
  // specializing code: code specialization turns conditional branches into
  // uncond branches, and this code folds them.
  Function::iterator Begin = cast<BasicBlock>(VMap[&OldFunc->getEntryBlock()]);
  Function::iterator I = Begin;
  while (I != NewFunc->end()) {
    // Check if this block has become dead during inlining or other
    // simplifications. Note that the first block will appear dead, as it has
    // not yet been wired up properly.
    if (I != Begin && (pred_begin(I) == pred_end(I) ||
                       I->getSinglePredecessor() == I)) {
      BasicBlock *DeadBB = I++;
      DeleteDeadBlock(DeadBB);
      continue;
    }

    // We need to simplify conditional branches and switches with a constant
    // operand. We try to prune these out when cloning, but if the
    // simplification required looking through PHI nodes, those are only
    // available after forming the full basic block. That may leave some here,
    // and we still want to prune the dead code as early as possible.
    ConstantFoldTerminator(I);

    BranchInst *BI = dyn_cast<BranchInst>(I->getTerminator());
    if (!BI || BI->isConditional()) { ++I; continue; }

    BasicBlock *Dest = BI->getSuccessor(0);
    if (!Dest->getSinglePredecessor()) {
      ++I; continue;
    }

    // We shouldn't be able to get single-entry PHI nodes here, as instsimplify
    // above should have zapped all of them..
    assert(!isa<PHINode>(Dest->begin()));

    // We know all single-entry PHI nodes in the inlined function have been
    // removed, so we just need to splice the blocks.
    BI->eraseFromParent();

    // Make all PHI nodes that referred to Dest now refer to I as their source.
    Dest->replaceAllUsesWith(I);

    // Move all the instructions in the succ to the pred.
    I->getInstList().splice(I->end(), Dest->getInstList());

    // Remove the dest block.
    Dest->eraseFromParent();

    // Do not increment I, iteratively merge all things this block branches to.
  }

  // Make a final pass over the basic blocks from theh old function to gather
  // any return instructions which survived folding. We have to do this here
  // because we can iteratively remove and merge returns above.
  for (Function::iterator I = cast<BasicBlock>(VMap[&OldFunc->getEntryBlock()]),
                          E = NewFunc->end();
       I != E; ++I)
    if (ReturnInst *RI = dyn_cast<ReturnInst>(I->getTerminator()))
      Returns.push_back(RI);
}