CDSPass.cpp

   1 //===-- CDSPass.cpp - xxx -------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 // This file is distributed under the University of Illinois Open Source
   7 // License. See LICENSE.TXT for details.
   8 //
   9 //===----------------------------------------------------------------------===//
  10 //
  11 // This file is a modified version of ThreadSanitizer.cpp, a part of a race detector.
  12 //
  13 // The tool is under development, for the details about previous versions see
  14 // http://code.google.com/p/data-race-test
  15 //
  16 // The instrumentation phase is quite simple:
  17 //   - Insert calls to run-time library before every memory access.
  18 //      - Optimizations may apply to avoid instrumenting some of the accesses.
  19 //   - Insert calls at function entry/exit.
  20 // The rest is handled by the run-time library.
  21 //===----------------------------------------------------------------------===//
  22
  23 #include "llvm/ADT/Statistic.h"
  24 #include "llvm/ADT/StringExtras.h"
  25 #include "llvm/ADT/SmallString.h"
  26 #include "llvm/Analysis/ValueTracking.h"
  27 #include "llvm/Analysis/CaptureTracking.h"
  28 #include "llvm/IR/BasicBlock.h"
  29 #include "llvm/IR/Function.h"
  30 #include "llvm/IR/IRBuilder.h"
  31 #include "llvm/IR/Instructions.h"
  32 #include "llvm/IR/LLVMContext.h"
  33 #include "llvm/IR/LegacyPassManager.h"
  34 #include "llvm/IR/Module.h"
  35 #include "llvm/IR/PassManager.h"
  36 #include "llvm/Pass.h"
  37 #include "llvm/ProfileData/InstrProf.h"
  38 #include "llvm/Support/raw_ostream.h"
  39 #include "llvm/Support/AtomicOrdering.h"
  40 #include "llvm/Support/Debug.h"
  41 #include "llvm/Transforms/Scalar.h"
  42 #include "llvm/Transforms/Utils/Local.h"
  43 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
  44 #include "llvm/Transforms/IPO/PassManagerBuilder.h"
  45 #include "llvm/Transforms/Utils/EscapeEnumerator.h"
  46 #include <vector>
  47
  48 using namespace llvm;
  49
  50 #define DEBUG_TYPE "CDS"
  51 #include <llvm/IR/DebugLoc.h>
  52
  53 Value *getPosition( Instruction * I, IRBuilder <> IRB, bool print = false)
  54 {
  55         const DebugLoc & debug_location = I->getDebugLoc ();
  56         std::string position_string;
  57         {
  58                 llvm::raw_string_ostream position_stream (position_string);
  59                 debug_location . print (position_stream);
  60         }
  61
  62         if (print) {
  63                 errs() << position_string << "\n";
  64         }
  65
  66         return IRB.CreateGlobalStringPtr (position_string);
  67 }
  68
  69 STATISTIC(NumInstrumentedReads, "Number of instrumented reads");
  70 STATISTIC(NumInstrumentedWrites, "Number of instrumented writes");
  71 STATISTIC(NumAccessesWithBadSize, "Number of accesses with bad size");
  72 // STATISTIC(NumInstrumentedVtableWrites, "Number of vtable ptr writes");
  73 // STATISTIC(NumInstrumentedVtableReads, "Number of vtable ptr reads");
  74
  75 STATISTIC(NumOmittedReadsBeforeWrite,
  76           "Number of reads ignored due to following writes");
  77 STATISTIC(NumOmittedReadsFromConstantGlobals,
  78           "Number of reads from constant globals");
  79 STATISTIC(NumOmittedReadsFromVtable, "Number of vtable reads");
  80 STATISTIC(NumOmittedNonCaptured, "Number of accesses ignored due to capturing");
  81
  82 Type * OrdTy;
  83
  84 Type * Int8PtrTy;
  85 Type * Int16PtrTy;
  86 Type * Int32PtrTy;
  87 Type * Int64PtrTy;
  88
  89 Type * VoidTy;
  90
  91 static const size_t kNumberOfAccessSizes = 4;
  92
  93 int getAtomicOrderIndex(AtomicOrdering order){
  94         switch (order) {
  95                 case AtomicOrdering::Monotonic:
  96                         return (int)AtomicOrderingCABI::relaxed;
  97                 //  case AtomicOrdering::Consume:         // not specified yet
  98                 //    return AtomicOrderingCABI::consume;
  99                 case AtomicOrdering::Acquire:
 100                         return (int)AtomicOrderingCABI::acquire;
 101                 case AtomicOrdering::Release:
 102                         return (int)AtomicOrderingCABI::release;
 103                 case AtomicOrdering::AcquireRelease:
 104                         return (int)AtomicOrderingCABI::acq_rel;
 105                 case AtomicOrdering::SequentiallyConsistent:
 106                         return (int)AtomicOrderingCABI::seq_cst;
 107                 default:
 108                         // unordered or Not Atomic
 109                         return -1;
 110         }
 111 }
 112
 113 namespace {
 114         struct CDSPass : public FunctionPass {
 115                 static char ID;
 116                 CDSPass() : FunctionPass(ID) {}
 117                 bool runOnFunction(Function &F) override;
 118
 119         private:
 120                 void initializeCallbacks(Module &M);
 121                 bool instrumentLoadOrStore(Instruction *I, const DataLayout &DL);
 122                 bool instrumentVolatile(Instruction *I, const DataLayout &DL);
 123                 bool isAtomicCall(Instruction *I);
 124                 bool instrumentAtomic(Instruction *I, const DataLayout &DL);
 125                 bool instrumentAtomicCall(CallInst *CI, const DataLayout &DL);
 126                 void chooseInstructionsToInstrument(SmallVectorImpl<Instruction *> &Local,
 127                                                                                         SmallVectorImpl<Instruction *> &All,
 128                                                                                         const DataLayout &DL);
 129                 bool addrPointsToConstantData(Value *Addr);
 130                 int getMemoryAccessFuncIndex(Value *Addr, const DataLayout &DL);
 131
 132                 // Callbacks to run-time library are computed in doInitialization.
 133                 Constant * CDSFuncEntry;
 134                 Constant * CDSFuncExit;
 135
 136                 Constant * CDSLoad[kNumberOfAccessSizes];
 137                 Constant * CDSStore[kNumberOfAccessSizes];
 138                 Constant * CDSVolatileLoad[kNumberOfAccessSizes];
 139                 Constant * CDSVolatileStore[kNumberOfAccessSizes];
 140                 Constant * CDSAtomicInit[kNumberOfAccessSizes];
 141                 Constant * CDSAtomicLoad[kNumberOfAccessSizes];
 142                 Constant * CDSAtomicStore[kNumberOfAccessSizes];
 143                 Constant * CDSAtomicRMW[AtomicRMWInst::LAST_BINOP + 1][kNumberOfAccessSizes];
 144                 Constant * CDSAtomicCAS_V1[kNumberOfAccessSizes];
 145                 Constant * CDSAtomicCAS_V2[kNumberOfAccessSizes];
 146                 Constant * CDSAtomicThreadFence;
 147
 148                 std::vector<StringRef> AtomicFuncNames;
 149                 std::vector<StringRef> PartialAtomicFuncNames;
 150         };
 151 }
 152
 153 static bool isVtableAccess(Instruction *I) {
 154         if (MDNode *Tag = I->getMetadata(LLVMContext::MD_tbaa))
 155                 return Tag->isTBAAVtableAccess();
 156         return false;
 157 }
 158
 159 void CDSPass::initializeCallbacks(Module &M) {
 160         LLVMContext &Ctx = M.getContext();
 161
 162         Type * Int1Ty = Type::getInt1Ty(Ctx);
 163         OrdTy = Type::getInt32Ty(Ctx);
 164
 165         Int8PtrTy  = Type::getInt8PtrTy(Ctx);
 166         Int16PtrTy = Type::getInt16PtrTy(Ctx);
 167         Int32PtrTy = Type::getInt32PtrTy(Ctx);
 168         Int64PtrTy = Type::getInt64PtrTy(Ctx);
 169
 170         VoidTy = Type::getVoidTy(Ctx);
 171
 172         CDSFuncEntry = M.getOrInsertFunction("cds_func_entry",
 173                                                                 VoidTy, Int8PtrTy);
 174         CDSFuncExit = M.getOrInsertFunction("cds_func_exit",
 175                                                                 VoidTy, Int8PtrTy);
 176
 177         // Get the function to call from our untime library.
 178         for (unsigned i = 0; i < kNumberOfAccessSizes; i++) {
 179                 const unsigned ByteSize = 1U << i;
 180                 const unsigned BitSize = ByteSize * 8;
 181
 182                 std::string ByteSizeStr = utostr(ByteSize);
 183                 std::string BitSizeStr = utostr(BitSize);
 184
 185                 Type *Ty = Type::getIntNTy(Ctx, BitSize);
 186                 Type *PtrTy = Ty->getPointerTo();
 187
 188                 // uint8_t cds_atomic_load8 (void * obj, int atomic_index)
 189                 // void cds_atomic_store8 (void * obj, int atomic_index, uint8_t val)
 190                 SmallString<32> LoadName("cds_load" + BitSizeStr);
 191                 SmallString<32> StoreName("cds_store" + BitSizeStr);
 192                 SmallString<32> VolatileLoadName("cds_volatile_load" + BitSizeStr);
 193                 SmallString<32> VolatileStoreName("cds_volatile_store" + BitSizeStr);
 194                 SmallString<32> AtomicInitName("cds_atomic_init" + BitSizeStr);
 195                 SmallString<32> AtomicLoadName("cds_atomic_load" + BitSizeStr);
 196                 SmallString<32> AtomicStoreName("cds_atomic_store" + BitSizeStr);
 197
 198                 CDSLoad[i]  = M.getOrInsertFunction(LoadName, VoidTy, PtrTy);
 199                 CDSStore[i] = M.getOrInsertFunction(StoreName, VoidTy, PtrTy);
 200                 CDSVolatileLoad[i]  = M.getOrInsertFunction(VolatileLoadName,
 201                                                                         Ty, PtrTy, Int8PtrTy);
 202                 CDSVolatileStore[i] = M.getOrInsertFunction(VolatileStoreName,
 203                                                                         VoidTy, PtrTy, Ty, Int8PtrTy);
 204                 CDSAtomicInit[i] = M.getOrInsertFunction(AtomicInitName,
 205                                                                 VoidTy, PtrTy, Ty, Int8PtrTy);
 206                 CDSAtomicLoad[i]  = M.getOrInsertFunction(AtomicLoadName,
 207                                                                 Ty, PtrTy, OrdTy, Int8PtrTy);
 208                 CDSAtomicStore[i] = M.getOrInsertFunction(AtomicStoreName,
 209                                                                 VoidTy, PtrTy, Ty, OrdTy, Int8PtrTy);
 210
 211                 for (int op = AtomicRMWInst::FIRST_BINOP;
 212                         op <= AtomicRMWInst::LAST_BINOP; ++op) {
 213                         CDSAtomicRMW[op][i] = nullptr;
 214                         std::string NamePart;
 215
 216                         if (op == AtomicRMWInst::Xchg)
 217                                 NamePart = "_exchange";
 218                         else if (op == AtomicRMWInst::Add)
 219                                 NamePart = "_fetch_add";
 220                         else if (op == AtomicRMWInst::Sub)
 221                                 NamePart = "_fetch_sub";
 222                         else if (op == AtomicRMWInst::And)
 223                                 NamePart = "_fetch_and";
 224                         else if (op == AtomicRMWInst::Or)
 225                                 NamePart = "_fetch_or";
 226                         else if (op == AtomicRMWInst::Xor)
 227                                 NamePart = "_fetch_xor";
 228                         else
 229                                 continue;
 230
 231                         SmallString<32> AtomicRMWName("cds_atomic" + NamePart + BitSizeStr);
 232                         CDSAtomicRMW[op][i] = M.getOrInsertFunction(AtomicRMWName,
 233                                                                                 Ty, PtrTy, Ty, OrdTy, Int8PtrTy);
 234                 }
 235
 236                 // only supportes strong version
 237                 SmallString<32> AtomicCASName_V1("cds_atomic_compare_exchange" + BitSizeStr + "_v1");
 238                 SmallString<32> AtomicCASName_V2("cds_atomic_compare_exchange" + BitSizeStr + "_v2");
 239                 CDSAtomicCAS_V1[i] = M.getOrInsertFunction(AtomicCASName_V1,
 240                                                                 Ty, PtrTy, Ty, Ty, OrdTy, OrdTy, Int8PtrTy);
 241                 CDSAtomicCAS_V2[i] = M.getOrInsertFunction(AtomicCASName_V2,
 242                                                                 Int1Ty, PtrTy, PtrTy, Ty, OrdTy, OrdTy, Int8PtrTy);
 243         }
 244
 245         CDSAtomicThreadFence = M.getOrInsertFunction("cds_atomic_thread_fence",
 246                                                                                                         VoidTy, OrdTy, Int8PtrTy);
 247 }
 248
 249 static bool shouldInstrumentReadWriteFromAddress(const Module *M, Value *Addr) {
 250         // Peel off GEPs and BitCasts.
 251         Addr = Addr->stripInBoundsOffsets();
 252
 253         if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Addr)) {
 254                 if (GV->hasSection()) {
 255                         StringRef SectionName = GV->getSection();
 256                         // Check if the global is in the PGO counters section.
 257                         auto OF = Triple(M->getTargetTriple()).getObjectFormat();
 258                         if (SectionName.endswith(
 259                               getInstrProfSectionName(IPSK_cnts, OF, /*AddSegmentInfo=*/false)))
 260                                 return false;
 261                 }
 262
 263                 // Check if the global is private gcov data.
 264                 if (GV->getName().startswith("__llvm_gcov") ||
 265                 GV->getName().startswith("__llvm_gcda"))
 266                 return false;
 267         }
 268
 269         // Do not instrument acesses from different address spaces; we cannot deal
 270         // with them.
 271         if (Addr) {
 272                 Type *PtrTy = cast<PointerType>(Addr->getType()->getScalarType());
 273                 if (PtrTy->getPointerAddressSpace() != 0)
 274                         return false;
 275         }
 276
 277         return true;
 278 }
 279
 280 bool CDSPass::addrPointsToConstantData(Value *Addr) {
 281         // If this is a GEP, just analyze its pointer operand.
 282         if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Addr))
 283                 Addr = GEP->getPointerOperand();
 284
 285         if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Addr)) {
 286                 if (GV->isConstant()) {
 287                         // Reads from constant globals can not race with any writes.
 288                         NumOmittedReadsFromConstantGlobals++;
 289                         return true;
 290                 }
 291         } else if (LoadInst *L = dyn_cast<LoadInst>(Addr)) {
 292                 if (isVtableAccess(L)) {
 293                         // Reads from a vtable pointer can not race with any writes.
 294                         NumOmittedReadsFromVtable++;
 295                         return true;
 296                 }
 297         }
 298         return false;
 299 }
 300
 301 bool CDSPass::runOnFunction(Function &F) {
 302         if (F.getName() == "main") {
 303                 F.setName("user_main");
 304                 errs() << "main replaced by user_main\n";
 305         }
 306
 307         if (true) {
 308                 initializeCallbacks( *F.getParent() );
 309
 310                 AtomicFuncNames =
 311                 {
 312                         "atomic_init", "atomic_load", "atomic_store",
 313                         "atomic_fetch_", "atomic_exchange", "atomic_compare_exchange_"
 314                 };
 315
 316                 PartialAtomicFuncNames =
 317                 {
 318                         "load", "store", "fetch", "exchange", "compare_exchange_"
 319                 };
 320
 321                 SmallVector<Instruction*, 8> AllLoadsAndStores;
 322                 SmallVector<Instruction*, 8> LocalLoadsAndStores;
 323                 SmallVector<Instruction*, 8> VolatileLoadsAndStores;
 324                 SmallVector<Instruction*, 8> AtomicAccesses;
 325
 326                 std::vector<Instruction *> worklist;
 327
 328                 bool Res = false;
 329                 bool HasAtomic = false;
 330                 const DataLayout &DL = F.getParent()->getDataLayout();
 331
 332                 // errs() << "--- " << F.getName() << "---\n";
 333
 334                 for (auto &B : F) {
 335                         for (auto &I : B) {
 336                                 if ( (&I)->isAtomic() || isAtomicCall(&I) ) {
 337                                         AtomicAccesses.push_back(&I);
 338                                         HasAtomic = true;
 339                                 } else if (isa<LoadInst>(I) || isa<StoreInst>(I)) {
 340                                         LoadInst *LI = dyn_cast<LoadInst>(&I);
 341                                         StoreInst *SI = dyn_cast<StoreInst>(&I);
 342                                         bool isVolatile = ( LI ? LI->isVolatile() : SI->isVolatile() );
 343
 344                                         if (isVolatile)
 345                                                 VolatileLoadsAndStores.push_back(&I);
 346                                         else
 347                                                 LocalLoadsAndStores.push_back(&I);
 348                                 } else if (isa<CallInst>(I) || isa<InvokeInst>(I)) {
 349                                         // not implemented yet
 350                                 }
 351                         }
 352
 353                         chooseInstructionsToInstrument(LocalLoadsAndStores, AllLoadsAndStores, DL);
 354                 }
 355
 356                 for (auto Inst : AllLoadsAndStores) {
 357                         Res |= instrumentLoadOrStore(Inst, DL);
 358                 }
 359
 360                 for (auto Inst : VolatileLoadsAndStores) {
 361                         Res |= instrumentVolatile(Inst, DL);
 362                 }
 363
 364                 for (auto Inst : AtomicAccesses) {
 365                         Res |= instrumentAtomic(Inst, DL);
 366                 }
 367
 368                 // only instrument functions that contain atomics
 369                 if (Res && HasAtomic) {
 370                         IRBuilder<> IRB(F.getEntryBlock().getFirstNonPHI());
 371                         /* Unused for now
 372                         Value *ReturnAddress = IRB.CreateCall(
 373                                 Intrinsic::getDeclaration(F.getParent(), Intrinsic::returnaddress),
 374                                 IRB.getInt32(0));
 375                         */
 376
 377                         Value * FuncName = IRB.CreateGlobalStringPtr(F.getName());
 378                         IRB.CreateCall(CDSFuncEntry, FuncName);
 379
 380                         EscapeEnumerator EE(F, "cds_cleanup", true);
 381                         while (IRBuilder<> *AtExit = EE.Next()) {
 382                           AtExit->CreateCall(CDSFuncExit, FuncName);
 383                         }
 384
 385                         Res = true;
 386                 }
 387         }
 388
 389         return false;
 390 }
 391
 392 void CDSPass::chooseInstructionsToInstrument(
 393         SmallVectorImpl<Instruction *> &Local, SmallVectorImpl<Instruction *> &All,
 394         const DataLayout &DL) {
 395         SmallPtrSet<Value*, 8> WriteTargets;
 396         // Iterate from the end.
 397         for (Instruction *I : reverse(Local)) {
 398                 if (StoreInst *Store = dyn_cast<StoreInst>(I)) {
 399                         Value *Addr = Store->getPointerOperand();
 400                         if (!shouldInstrumentReadWriteFromAddress(I->getModule(), Addr))
 401                                 continue;
 402                         WriteTargets.insert(Addr);
 403                 } else {
 404                         LoadInst *Load = cast<LoadInst>(I);
 405                         Value *Addr = Load->getPointerOperand();
 406                         if (!shouldInstrumentReadWriteFromAddress(I->getModule(), Addr))
 407                                 continue;
 408                         if (WriteTargets.count(Addr)) {
 409                                 // We will write to this temp, so no reason to analyze the read.
 410                                 NumOmittedReadsBeforeWrite++;
 411                                 continue;
 412                         }
 413                         if (addrPointsToConstantData(Addr)) {
 414                                 // Addr points to some constant data -- it can not race with any writes.
 415                                 continue;
 416                         }
 417                 }
 418                 Value *Addr = isa<StoreInst>(*I)
 419                         ? cast<StoreInst>(I)->getPointerOperand()
 420                         : cast<LoadInst>(I)->getPointerOperand();
 421                 if (isa<AllocaInst>(GetUnderlyingObject(Addr, DL)) &&
 422                                 !PointerMayBeCaptured(Addr, true, true)) {
 423                         // The variable is addressable but not captured, so it cannot be
 424                         // referenced from a different thread and participate in a data race
 425                         // (see llvm/Analysis/CaptureTracking.h for details).
 426                         NumOmittedNonCaptured++;
 427                         continue;
 428                 }
 429                 All.push_back(I);
 430         }
 431         Local.clear();
 432 }
 433
 434
 435 bool CDSPass::instrumentLoadOrStore(Instruction *I,
 436                                                                         const DataLayout &DL) {
 437         IRBuilder<> IRB(I);
 438         bool IsWrite = isa<StoreInst>(*I);
 439         Value *Addr = IsWrite
 440                 ? cast<StoreInst>(I)->getPointerOperand()
 441                 : cast<LoadInst>(I)->getPointerOperand();
 442
 443         // swifterror memory addresses are mem2reg promoted by instruction selection.
 444         // As such they cannot have regular uses like an instrumentation function and
 445         // it makes no sense to track them as memory.
 446         if (Addr->isSwiftError())
 447         return false;
 448
 449         int Idx = getMemoryAccessFuncIndex(Addr, DL);
 450         if (Idx < 0)
 451                 return false;
 452
 453 //  not supported by CDS yet
 454 /*  if (IsWrite && isVtableAccess(I)) {
 455     LLVM_DEBUG(dbgs() << "  VPTR : " << *I << "\n");
 456     Value *StoredValue = cast<StoreInst>(I)->getValueOperand();
 457     // StoredValue may be a vector type if we are storing several vptrs at once.
 458     // In this case, just take the first element of the vector since this is
 459     // enough to find vptr races.
 460     if (isa<VectorType>(StoredValue->getType()))
 461       StoredValue = IRB.CreateExtractElement(
 462           StoredValue, ConstantInt::get(IRB.getInt32Ty(), 0));
 463     if (StoredValue->getType()->isIntegerTy())
 464       StoredValue = IRB.CreateIntToPtr(StoredValue, IRB.getInt8PtrTy());
 465     // Call TsanVptrUpdate.
 466     IRB.CreateCall(TsanVptrUpdate,
 467                    {IRB.CreatePointerCast(Addr, IRB.getInt8PtrTy()),
 468                     IRB.CreatePointerCast(StoredValue, IRB.getInt8PtrTy())});
 469     NumInstrumentedVtableWrites++;
 470     return true;
 471   }
 472
 473   if (!IsWrite && isVtableAccess(I)) {
 474     IRB.CreateCall(TsanVptrLoad,
 475                    IRB.CreatePointerCast(Addr, IRB.getInt8PtrTy()));
 476     NumInstrumentedVtableReads++;
 477     return true;
 478   }
 479 */
 480
 481         Value *OnAccessFunc = nullptr;
 482         OnAccessFunc = IsWrite ? CDSStore[Idx] : CDSLoad[Idx];
 483
 484         Type *ArgType = IRB.CreatePointerCast(Addr, Addr->getType())->getType();
 485
 486         if ( ArgType != Int8PtrTy && ArgType != Int16PtrTy &&
 487                         ArgType != Int32PtrTy && ArgType != Int64PtrTy ) {
 488                 // if other types of load or stores are passed in
 489                 return false;
 490         }
 491         IRB.CreateCall(OnAccessFunc, IRB.CreatePointerCast(Addr, Addr->getType()));
 492         if (IsWrite) NumInstrumentedWrites++;
 493         else         NumInstrumentedReads++;
 494         return true;
 495 }
 496
 497 bool CDSPass::instrumentVolatile(Instruction * I, const DataLayout &DL) {
 498         IRBuilder<> IRB(I);
 499         Value *position = getPosition(I, IRB);
 500
 501         if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
 502                 assert( LI->isVolatile() );
 503                 Value *Addr = LI->getPointerOperand();
 504                 int Idx=getMemoryAccessFuncIndex(Addr, DL);
 505                 if (Idx < 0)
 506                         return false;
 507
 508                 Value *args[] = {Addr, position};
 509                 Instruction* funcInst=CallInst::Create(CDSVolatileLoad[Idx], args);
 510                 ReplaceInstWithInst(LI, funcInst);
 511         } else if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
 512                 assert( SI->isVolatile() );
 513                 Value *Addr = SI->getPointerOperand();
 514                 int Idx=getMemoryAccessFuncIndex(Addr, DL);
 515                 if (Idx < 0)
 516                         return false;
 517
 518                 Value *val = SI->getValueOperand();
 519                 Value *args[] = {Addr, val, position};
 520                 Instruction* funcInst=CallInst::Create(CDSVolatileStore[Idx], args);
 521                 ReplaceInstWithInst(SI, funcInst);
 522         } else {
 523                 return false;
 524         }
 525
 526         return true;
 527 }
 528
 529 bool CDSPass::instrumentAtomic(Instruction * I, const DataLayout &DL) {
 530         IRBuilder<> IRB(I);
 531
 532         if (auto *CI = dyn_cast<CallInst>(I)) {
 533                 return instrumentAtomicCall(CI, DL);
 534         }
 535
 536         Value *position = getPosition(I, IRB);
 537
 538         if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
 539                 Value *Addr = LI->getPointerOperand();
 540                 int Idx=getMemoryAccessFuncIndex(Addr, DL);
 541                 if (Idx < 0)
 542                         return false;
 543
 544                 int atomic_order_index = getAtomicOrderIndex(LI->getOrdering());
 545                 Value *order = ConstantInt::get(OrdTy, atomic_order_index);
 546                 Value *args[] = {Addr, order, position};
 547                 Instruction* funcInst=CallInst::Create(CDSAtomicLoad[Idx], args);
 548                 ReplaceInstWithInst(LI, funcInst);
 549         } else if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
 550                 Value *Addr = SI->getPointerOperand();
 551                 int Idx=getMemoryAccessFuncIndex(Addr, DL);
 552                 if (Idx < 0)
 553                         return false;
 554
 555                 int atomic_order_index = getAtomicOrderIndex(SI->getOrdering());
 556                 Value *val = SI->getValueOperand();
 557                 Value *order = ConstantInt::get(OrdTy, atomic_order_index);
 558                 Value *args[] = {Addr, val, order, position};
 559                 Instruction* funcInst=CallInst::Create(CDSAtomicStore[Idx], args);
 560                 ReplaceInstWithInst(SI, funcInst);
 561         } else if (AtomicRMWInst *RMWI = dyn_cast<AtomicRMWInst>(I)) {
 562                 Value *Addr = RMWI->getPointerOperand();
 563                 int Idx=getMemoryAccessFuncIndex(Addr, DL);
 564                 if (Idx < 0)
 565                         return false;
 566
 567                 int atomic_order_index = getAtomicOrderIndex(RMWI->getOrdering());
 568                 Value *val = RMWI->getValOperand();
 569                 Value *order = ConstantInt::get(OrdTy, atomic_order_index);
 570                 Value *args[] = {Addr, val, order, position};
 571                 Instruction* funcInst = CallInst::Create(CDSAtomicRMW[RMWI->getOperation()][Idx], args);
 572                 ReplaceInstWithInst(RMWI, funcInst);
 573         } else if (AtomicCmpXchgInst *CASI = dyn_cast<AtomicCmpXchgInst>(I)) {
 574                 IRBuilder<> IRB(CASI);
 575
 576                 Value *Addr = CASI->getPointerOperand();
 577                 int Idx=getMemoryAccessFuncIndex(Addr, DL);
 578                 if (Idx < 0)
 579                         return false;
 580
 581                 const unsigned ByteSize = 1U << Idx;
 582                 const unsigned BitSize = ByteSize * 8;
 583                 Type *Ty = Type::getIntNTy(IRB.getContext(), BitSize);
 584                 Type *PtrTy = Ty->getPointerTo();
 585
 586                 Value *CmpOperand = IRB.CreateBitOrPointerCast(CASI->getCompareOperand(), Ty);
 587                 Value *NewOperand = IRB.CreateBitOrPointerCast(CASI->getNewValOperand(), Ty);
 588
 589                 int atomic_order_index_succ = getAtomicOrderIndex(CASI->getSuccessOrdering());
 590                 int atomic_order_index_fail = getAtomicOrderIndex(CASI->getFailureOrdering());
 591                 Value *order_succ = ConstantInt::get(OrdTy, atomic_order_index_succ);
 592                 Value *order_fail = ConstantInt::get(OrdTy, atomic_order_index_fail);
 593
 594                 Value *Args[] = {IRB.CreatePointerCast(Addr, PtrTy),
 595                                                  CmpOperand, NewOperand,
 596                                                  order_succ, order_fail, position};
 597
 598                 CallInst *funcInst = IRB.CreateCall(CDSAtomicCAS_V1[Idx], Args);
 599                 Value *Success = IRB.CreateICmpEQ(funcInst, CmpOperand);
 600
 601                 Value *OldVal = funcInst;
 602                 Type *OrigOldValTy = CASI->getNewValOperand()->getType();
 603                 if (Ty != OrigOldValTy) {
 604                         // The value is a pointer, so we need to cast the return value.
 605                         OldVal = IRB.CreateIntToPtr(funcInst, OrigOldValTy);
 606                 }
 607
 608                 Value *Res =
 609                   IRB.CreateInsertValue(UndefValue::get(CASI->getType()), OldVal, 0);
 610                 Res = IRB.CreateInsertValue(Res, Success, 1);
 611
 612                 I->replaceAllUsesWith(Res);
 613                 I->eraseFromParent();
 614         } else if (FenceInst *FI = dyn_cast<FenceInst>(I)) {
 615                 int atomic_order_index = getAtomicOrderIndex(FI->getOrdering());
 616                 Value *order = ConstantInt::get(OrdTy, atomic_order_index);
 617                 Value *Args[] = {order, position};
 618
 619                 CallInst *funcInst = CallInst::Create(CDSAtomicThreadFence, Args);
 620                 ReplaceInstWithInst(FI, funcInst);
 621                 // errs() << "Thread Fences replaced\n";
 622         }
 623         return true;
 624 }
 625
 626 bool CDSPass::isAtomicCall(Instruction *I) {
 627         if ( auto *CI = dyn_cast<CallInst>(I) ) {
 628                 Function *fun = CI->getCalledFunction();
 629                 if (fun == NULL)
 630                         return false;
 631
 632                 StringRef funName = fun->getName();
 633
 634                 // todo: come up with better rules for function name checking
 635                 for (StringRef name : AtomicFuncNames) {
 636                         if ( funName.contains(name) )
 637                                 return true;
 638                 }
 639
 640                 for (StringRef PartialName : PartialAtomicFuncNames) {
 641                         if (funName.contains(PartialName) &&
 642                                         funName.contains("atomic") )
 643                                 return true;
 644                 }
 645         }
 646
 647         return false;
 648 }
 649
 650 bool CDSPass::instrumentAtomicCall(CallInst *CI, const DataLayout &DL) {
 651         IRBuilder<> IRB(CI);
 652         Function *fun = CI->getCalledFunction();
 653         StringRef funName = fun->getName();
 654         std::vector<Value *> parameters;
 655
 656         User::op_iterator begin = CI->arg_begin();
 657         User::op_iterator end = CI->arg_end();
 658         for (User::op_iterator it = begin; it != end; ++it) {
 659                 Value *param = *it;
 660                 parameters.push_back(param);
 661         }
 662
 663         // obtain source line number of the CallInst
 664         Value *position = getPosition(CI, IRB);
 665
 666         // the pointer to the address is always the first argument
 667         Value *OrigPtr = parameters[0];
 668
 669         int Idx = getMemoryAccessFuncIndex(OrigPtr, DL);
 670         if (Idx < 0)
 671                 return false;
 672
 673         const unsigned ByteSize = 1U << Idx;
 674         const unsigned BitSize = ByteSize * 8;
 675         Type *Ty = Type::getIntNTy(IRB.getContext(), BitSize);
 676         Type *PtrTy = Ty->getPointerTo();
 677
 678         // atomic_init; args = {obj, order}
 679         if (funName.contains("atomic_init")) {
 680                 Value *ptr = IRB.CreatePointerCast(OrigPtr, PtrTy);
 681                 Value *val = IRB.CreateBitOrPointerCast(parameters[1], Ty);
 682                 Value *args[] = {ptr, val, position};
 683
 684                 Instruction* funcInst = CallInst::Create(CDSAtomicInit[Idx], args);
 685                 ReplaceInstWithInst(CI, funcInst);
 686
 687                 return true;
 688         }
 689
 690         // atomic_load; args = {obj, order}
 691         if (funName.contains("atomic_load")) {
 692                 bool isExplicit = funName.contains("atomic_load_explicit");
 693
 694                 Value *ptr = IRB.CreatePointerCast(OrigPtr, PtrTy);
 695                 Value *order;
 696                 if (isExplicit)
 697                         order = IRB.CreateBitOrPointerCast(parameters[1], OrdTy);
 698                 else
 699                         order = ConstantInt::get(OrdTy,
 700                                                         (int) AtomicOrderingCABI::seq_cst);
 701                 Value *args[] = {ptr, order, position};
 702
 703                 Instruction* funcInst = CallInst::Create(CDSAtomicLoad[Idx], args);
 704                 ReplaceInstWithInst(CI, funcInst);
 705
 706                 return true;
 707         } else if (funName.contains("atomic") &&
 708                                         funName.contains("load") ) {
 709                 // does this version of call always have an atomic order as an argument?
 710                 Value *ptr = IRB.CreatePointerCast(OrigPtr, PtrTy);
 711                 Value *order = IRB.CreateBitOrPointerCast(parameters[1], OrdTy);
 712                 Value *args[] = {ptr, order, position};
 713
 714                 if (!CI->getType()->isPointerTy()) {
 715                         return false;
 716                 }
 717
 718                 CallInst *funcInst = IRB.CreateCall(CDSAtomicLoad[Idx], args);
 719                 Value *RetVal = IRB.CreateIntToPtr(funcInst, CI->getType());
 720
 721                 CI->replaceAllUsesWith(RetVal);
 722                 CI->eraseFromParent();
 723
 724                 return true;
 725         }
 726
 727         // atomic_store; args = {obj, val, order}
 728         if (funName.contains("atomic_store")) {
 729                 bool isExplicit = funName.contains("atomic_store_explicit");
 730                 Value *OrigVal = parameters[1];
 731
 732                 Value *ptr = IRB.CreatePointerCast(OrigPtr, PtrTy);
 733                 Value *val = IRB.CreatePointerCast(OrigVal, Ty);
 734                 Value *order;
 735                 if (isExplicit)
 736                         order = IRB.CreateBitOrPointerCast(parameters[2], OrdTy);
 737                 else
 738                         order = ConstantInt::get(OrdTy,
 739                                                         (int) AtomicOrderingCABI::seq_cst);
 740                 Value *args[] = {ptr, val, order, position};
 741
 742                 Instruction* funcInst = CallInst::Create(CDSAtomicStore[Idx], args);
 743                 ReplaceInstWithInst(CI, funcInst);
 744
 745                 return true;
 746         } else if (funName.contains("atomic") &&
 747                                         funName.contains("EEEE5store") ) {
 748                 // does this version of call always have an atomic order as an argument?
 749                 Value *OrigVal = parameters[1];
 750
 751                 Value *ptr = IRB.CreatePointerCast(OrigPtr, PtrTy);
 752                 Value *val = IRB.CreatePointerCast(OrigVal, Ty);
 753                 Value *order = IRB.CreateBitOrPointerCast(parameters[2], OrdTy);
 754                 Value *args[] = {ptr, val, order, position};
 755
 756                 Instruction* funcInst = CallInst::Create(CDSAtomicStore[Idx], args);
 757                 ReplaceInstWithInst(CI, funcInst);
 758
 759                 return true;
 760         }
 761
 762         // atomic_fetch_*; args = {obj, val, order}
 763         if (funName.contains("atomic_fetch_") ||
 764                         funName.contains("atomic_exchange") ) {
 765                 bool isExplicit = funName.contains("_explicit");
 766                 Value *OrigVal = parameters[1];
 767
 768                 int op;
 769                 if ( funName.contains("_fetch_add") )
 770                         op = AtomicRMWInst::Add;
 771                 else if ( funName.contains("_fetch_sub") )
 772                         op = AtomicRMWInst::Sub;
 773                 else if ( funName.contains("_fetch_and") )
 774                         op = AtomicRMWInst::And;
 775                 else if ( funName.contains("_fetch_or") )
 776                         op = AtomicRMWInst::Or;
 777                 else if ( funName.contains("_fetch_xor") )
 778                         op = AtomicRMWInst::Xor;
 779                 else if ( funName.contains("atomic_exchange") )
 780                         op = AtomicRMWInst::Xchg;
 781                 else {
 782                         errs() << "Unknown atomic read-modify-write operation\n";
 783                         return false;
 784                 }
 785
 786                 Value *ptr = IRB.CreatePointerCast(OrigPtr, PtrTy);
 787                 Value *val = IRB.CreatePointerCast(OrigVal, Ty);
 788                 Value *order;
 789                 if (isExplicit)
 790                         order = IRB.CreateBitOrPointerCast(parameters[2], OrdTy);
 791                 else
 792                         order = ConstantInt::get(OrdTy,
 793                                                         (int) AtomicOrderingCABI::seq_cst);
 794                 Value *args[] = {ptr, val, order, position};
 795
 796                 Instruction* funcInst = CallInst::Create(CDSAtomicRMW[op][Idx], args);
 797                 ReplaceInstWithInst(CI, funcInst);
 798
 799                 return true;
 800         } else if (funName.contains("fetch")) {
 801                 errs() << "atomic exchange captured. Not implemented yet. ";
 802                 errs() << "See source file :";
 803                 getPosition(CI, IRB, true);
 804         } else if (funName.contains("exchange") &&
 805                         !funName.contains("compare_exchange") ) {
 806                 errs() << "atomic exchange captured. Not implemented yet. ";
 807                 errs() << "See source file :";
 808                 getPosition(CI, IRB, true);
 809         }
 810
 811         /* atomic_compare_exchange_*;
 812            args = {obj, expected, new value, order1, order2}
 813         */
 814         if ( funName.contains("atomic_compare_exchange_") ) {
 815                 bool isExplicit = funName.contains("_explicit");
 816
 817                 Value *Addr = IRB.CreatePointerCast(OrigPtr, PtrTy);
 818                 Value *CmpOperand = IRB.CreatePointerCast(parameters[1], PtrTy);
 819                 Value *NewOperand = IRB.CreateBitOrPointerCast(parameters[2], Ty);
 820
 821                 Value *order_succ, *order_fail;
 822                 if (isExplicit) {
 823                         order_succ = IRB.CreateBitOrPointerCast(parameters[3], OrdTy);
 824                         order_fail = IRB.CreateBitOrPointerCast(parameters[4], OrdTy);
 825                 } else  {
 826                         order_succ = ConstantInt::get(OrdTy,
 827                                                         (int) AtomicOrderingCABI::seq_cst);
 828                         order_fail = ConstantInt::get(OrdTy,
 829                                                         (int) AtomicOrderingCABI::seq_cst);
 830                 }
 831
 832                 Value *args[] = {Addr, CmpOperand, NewOperand,
 833                                                         order_succ, order_fail, position};
 834
 835                 Instruction* funcInst = CallInst::Create(CDSAtomicCAS_V2[Idx], args);
 836                 ReplaceInstWithInst(CI, funcInst);
 837
 838                 return true;
 839         } else if ( funName.contains("compare_exchange_strong") ||
 840                                 funName.contains("compare_exchange_weak") ) {
 841                 Value *Addr = IRB.CreatePointerCast(OrigPtr, PtrTy);
 842                 Value *CmpOperand = IRB.CreatePointerCast(parameters[1], PtrTy);
 843                 Value *NewOperand = IRB.CreateBitOrPointerCast(parameters[2], Ty);
 844
 845                 Value *order_succ, *order_fail;
 846                 order_succ = IRB.CreateBitOrPointerCast(parameters[3], OrdTy);
 847                 order_fail = IRB.CreateBitOrPointerCast(parameters[4], OrdTy);
 848
 849                 Value *args[] = {Addr, CmpOperand, NewOperand,
 850                                                         order_succ, order_fail, position};
 851                 Instruction* funcInst = CallInst::Create(CDSAtomicCAS_V2[Idx], args);
 852                 ReplaceInstWithInst(CI, funcInst);
 853
 854                 return true;
 855         }
 856
 857         return false;
 858 }
 859
 860 int CDSPass::getMemoryAccessFuncIndex(Value *Addr,
 861                                                                                 const DataLayout &DL) {
 862         Type *OrigPtrTy = Addr->getType();
 863         Type *OrigTy = cast<PointerType>(OrigPtrTy)->getElementType();
 864         assert(OrigTy->isSized());
 865         uint32_t TypeSize = DL.getTypeStoreSizeInBits(OrigTy);
 866         if (TypeSize != 8  && TypeSize != 16 &&
 867                 TypeSize != 32 && TypeSize != 64 && TypeSize != 128) {
 868                 NumAccessesWithBadSize++;
 869                 // Ignore all unusual sizes.
 870                 return -1;
 871         }
 872         size_t Idx = countTrailingZeros(TypeSize / 8);
 873         //assert(Idx < kNumberOfAccessSizes);
 874         if (Idx >= kNumberOfAccessSizes) {
 875                 return -1;
 876         }
 877         return Idx;
 878 }
 879
 880
 881 char CDSPass::ID = 0;
 882
 883 // Automatically enable the pass.
 884 static void registerCDSPass(const PassManagerBuilder &,
 885                                                         legacy::PassManagerBase &PM) {
 886         PM.add(new CDSPass());
 887 }
 888
 889 /* Enable the pass when opt level is greater than 0 */
 890 static RegisterStandardPasses
 891         RegisterMyPass1(PassManagerBuilder::EP_OptimizerLast,
 892 registerCDSPass);
 893
 894 /* Enable the pass when opt level is 0 */
 895 static RegisterStandardPasses
 896         RegisterMyPass2(PassManagerBuilder::EP_EnabledOnOptLevel0,
 897 registerCDSPass);