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;
  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 isAtomicCall(Instruction *I);
 123                 bool instrumentAtomic(Instruction *I, const DataLayout &DL);
 124                 bool instrumentAtomicCall(CallInst *CI, const DataLayout &DL);
 125                 void chooseInstructionsToInstrument(SmallVectorImpl<Instruction *> &Local,
 126                                                                                         SmallVectorImpl<Instruction *> &All,
 127                                                                                         const DataLayout &DL);
 128                 bool addrPointsToConstantData(Value *Addr);
 129                 int getMemoryAccessFuncIndex(Value *Addr, const DataLayout &DL);
 130
 131                 // Callbacks to run-time library are computed in doInitialization.
 132                 Constant * CDSFuncEntry;
 133                 Constant * CDSFuncExit;
 134
 135                 Constant * CDSLoad[kNumberOfAccessSizes];
 136                 Constant * CDSStore[kNumberOfAccessSizes];
 137                 Constant * CDSAtomicInit[kNumberOfAccessSizes];
 138                 Constant * CDSAtomicLoad[kNumberOfAccessSizes];
 139                 Constant * CDSAtomicStore[kNumberOfAccessSizes];
 140                 Constant * CDSAtomicRMW[AtomicRMWInst::LAST_BINOP + 1][kNumberOfAccessSizes];
 141                 Constant * CDSAtomicCAS_V1[kNumberOfAccessSizes];
 142                 Constant * CDSAtomicCAS_V2[kNumberOfAccessSizes];
 143                 Constant * CDSAtomicThreadFence;
 144
 145                 std::vector<StringRef> AtomicFuncNames;
 146                 std::vector<StringRef> PartialAtomicFuncNames;
 147         };
 148 }
 149
 150 static bool isVtableAccess(Instruction *I) {
 151         if (MDNode *Tag = I->getMetadata(LLVMContext::MD_tbaa))
 152                 return Tag->isTBAAVtableAccess();
 153         return false;
 154 }
 155
 156 void CDSPass::initializeCallbacks(Module &M) {
 157         LLVMContext &Ctx = M.getContext();
 158
 159         Type * Int1Ty = Type::getInt1Ty(Ctx);
 160         OrdTy = Type::getInt32Ty(Ctx);
 161
 162         Int8PtrTy  = Type::getInt8PtrTy(Ctx);
 163         Int16PtrTy = Type::getInt16PtrTy(Ctx);
 164         Int32PtrTy = Type::getInt32PtrTy(Ctx);
 165         Int64PtrTy = Type::getInt64PtrTy(Ctx);
 166
 167         VoidTy = Type::getVoidTy(Ctx);
 168
 169         CDSFuncEntry = M.getOrInsertFunction("cds_func_entry",
 170                                                                 VoidTy, Int8PtrTy);
 171         CDSFuncExit = M.getOrInsertFunction("cds_func_exit",
 172                                                                 VoidTy, Int8PtrTy);
 173
 174         // Get the function to call from our untime library.
 175         for (unsigned i = 0; i < kNumberOfAccessSizes; i++) {
 176                 const unsigned ByteSize = 1U << i;
 177                 const unsigned BitSize = ByteSize * 8;
 178
 179                 std::string ByteSizeStr = utostr(ByteSize);
 180                 std::string BitSizeStr = utostr(BitSize);
 181
 182                 Type *Ty = Type::getIntNTy(Ctx, BitSize);
 183                 Type *PtrTy = Ty->getPointerTo();
 184
 185                 // uint8_t cds_atomic_load8 (void * obj, int atomic_index)
 186                 // void cds_atomic_store8 (void * obj, int atomic_index, uint8_t val)
 187                 SmallString<32> LoadName("cds_load" + BitSizeStr);
 188                 SmallString<32> StoreName("cds_store" + BitSizeStr);
 189                 SmallString<32> AtomicInitName("cds_atomic_init" + BitSizeStr);
 190                 SmallString<32> AtomicLoadName("cds_atomic_load" + BitSizeStr);
 191                 SmallString<32> AtomicStoreName("cds_atomic_store" + BitSizeStr);
 192
 193                 CDSLoad[i]  = M.getOrInsertFunction(LoadName, VoidTy, PtrTy);
 194                 CDSStore[i] = M.getOrInsertFunction(StoreName, VoidTy, PtrTy);
 195                 CDSAtomicInit[i] = M.getOrInsertFunction(AtomicInitName,
 196                                                                 VoidTy, PtrTy, Ty, Int8PtrTy);
 197                 CDSAtomicLoad[i]  = M.getOrInsertFunction(AtomicLoadName,
 198                                                                 Ty, PtrTy, OrdTy, Int8PtrTy);
 199                 CDSAtomicStore[i] = M.getOrInsertFunction(AtomicStoreName,
 200                                                                 VoidTy, PtrTy, Ty, OrdTy, Int8PtrTy);
 201
 202                 for (int op = AtomicRMWInst::FIRST_BINOP;
 203                         op <= AtomicRMWInst::LAST_BINOP; ++op) {
 204                         CDSAtomicRMW[op][i] = nullptr;
 205                         std::string NamePart;
 206
 207                         if (op == AtomicRMWInst::Xchg)
 208                                 NamePart = "_exchange";
 209                         else if (op == AtomicRMWInst::Add)
 210                                 NamePart = "_fetch_add";
 211                         else if (op == AtomicRMWInst::Sub)
 212                                 NamePart = "_fetch_sub";
 213                         else if (op == AtomicRMWInst::And)
 214                                 NamePart = "_fetch_and";
 215                         else if (op == AtomicRMWInst::Or)
 216                                 NamePart = "_fetch_or";
 217                         else if (op == AtomicRMWInst::Xor)
 218                                 NamePart = "_fetch_xor";
 219                         else
 220                                 continue;
 221
 222                         SmallString<32> AtomicRMWName("cds_atomic" + NamePart + BitSizeStr);
 223                         CDSAtomicRMW[op][i] = M.getOrInsertFunction(AtomicRMWName,
 224                                                                                 Ty, PtrTy, Ty, OrdTy, Int8PtrTy);
 225                 }
 226
 227                 // only supportes strong version
 228                 SmallString<32> AtomicCASName_V1("cds_atomic_compare_exchange" + BitSizeStr + "_v1");
 229                 SmallString<32> AtomicCASName_V2("cds_atomic_compare_exchange" + BitSizeStr + "_v2");
 230                 CDSAtomicCAS_V1[i] = M.getOrInsertFunction(AtomicCASName_V1,
 231                                                                 Ty, PtrTy, Ty, Ty, OrdTy, OrdTy, Int8PtrTy);
 232                 CDSAtomicCAS_V2[i] = M.getOrInsertFunction(AtomicCASName_V2,
 233                                                                 Int1Ty, PtrTy, PtrTy, Ty, OrdTy, OrdTy, Int8PtrTy);
 234         }
 235
 236         CDSAtomicThreadFence = M.getOrInsertFunction("cds_atomic_thread_fence",
 237                                                                                                         VoidTy, OrdTy, Int8PtrTy);
 238 }
 239
 240 static bool shouldInstrumentReadWriteFromAddress(const Module *M, Value *Addr) {
 241         // Peel off GEPs and BitCasts.
 242         Addr = Addr->stripInBoundsOffsets();
 243
 244         if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Addr)) {
 245                 if (GV->hasSection()) {
 246                         StringRef SectionName = GV->getSection();
 247                         // Check if the global is in the PGO counters section.
 248                         auto OF = Triple(M->getTargetTriple()).getObjectFormat();
 249                         if (SectionName.endswith(
 250                               getInstrProfSectionName(IPSK_cnts, OF, /*AddSegmentInfo=*/false)))
 251                                 return false;
 252                 }
 253
 254                 // Check if the global is private gcov data.
 255                 if (GV->getName().startswith("__llvm_gcov") ||
 256                 GV->getName().startswith("__llvm_gcda"))
 257                 return false;
 258         }
 259
 260         // Do not instrument acesses from different address spaces; we cannot deal
 261         // with them.
 262         if (Addr) {
 263                 Type *PtrTy = cast<PointerType>(Addr->getType()->getScalarType());
 264                 if (PtrTy->getPointerAddressSpace() != 0)
 265                         return false;
 266         }
 267
 268         return true;
 269 }
 270
 271 bool CDSPass::addrPointsToConstantData(Value *Addr) {
 272         // If this is a GEP, just analyze its pointer operand.
 273         if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Addr))
 274                 Addr = GEP->getPointerOperand();
 275
 276         if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Addr)) {
 277                 if (GV->isConstant()) {
 278                         // Reads from constant globals can not race with any writes.
 279                         NumOmittedReadsFromConstantGlobals++;
 280                         return true;
 281                 }
 282         } else if (LoadInst *L = dyn_cast<LoadInst>(Addr)) {
 283                 if (isVtableAccess(L)) {
 284                         // Reads from a vtable pointer can not race with any writes.
 285                         NumOmittedReadsFromVtable++;
 286                         return true;
 287                 }
 288         }
 289         return false;
 290 }
 291
 292 bool CDSPass::runOnFunction(Function &F) {
 293         if (F.getName() == "main") {
 294                 F.setName("user_main");
 295                 errs() << "main replaced by user_main\n";
 296         }
 297
 298         if (true) {
 299                 initializeCallbacks( *F.getParent() );
 300
 301                 AtomicFuncNames =
 302                 {
 303                         "atomic_init", "atomic_load", "atomic_store",
 304                         "atomic_fetch_", "atomic_exchange", "atomic_compare_exchange_"
 305                 };
 306
 307                 PartialAtomicFuncNames =
 308                 {
 309                         "load", "store", "fetch", "exchange", "compare_exchange_"
 310                 };
 311
 312                 SmallVector<Instruction*, 8> AllLoadsAndStores;
 313                 SmallVector<Instruction*, 8> LocalLoadsAndStores;
 314                 SmallVector<Instruction*, 8> AtomicAccesses;
 315
 316                 std::vector<Instruction *> worklist;
 317
 318                 bool Res = false;
 319                 bool HasAtomic = false;
 320                 const DataLayout &DL = F.getParent()->getDataLayout();
 321
 322                 // errs() << "--- " << F.getName() << "---\n";
 323
 324                 for (auto &B : F) {
 325                         for (auto &I : B) {
 326                                 if ( (&I)->isAtomic() || isAtomicCall(&I) ) {
 327                                         AtomicAccesses.push_back(&I);
 328                                         HasAtomic = true;
 329                                 } else if (isa<LoadInst>(I) || isa<StoreInst>(I)) {
 330                                         LocalLoadsAndStores.push_back(&I);
 331                                 } else if (isa<CallInst>(I) || isa<InvokeInst>(I)) {
 332                                         // not implemented yet
 333                                 }
 334                         }
 335
 336                         chooseInstructionsToInstrument(LocalLoadsAndStores, AllLoadsAndStores, DL);
 337                 }
 338
 339                 for (auto Inst : AllLoadsAndStores) {
 340                         Res |= instrumentLoadOrStore(Inst, DL);
 341                 }
 342
 343                 for (auto Inst : AtomicAccesses) {
 344                         Res |= instrumentAtomic(Inst, DL);
 345                 }
 346
 347                 // only instrument functions that contain atomics
 348                 if (Res && HasAtomic) {
 349                         IRBuilder<> IRB(F.getEntryBlock().getFirstNonPHI());
 350                         /* Unused for now
 351                         Value *ReturnAddress = IRB.CreateCall(
 352                                 Intrinsic::getDeclaration(F.getParent(), Intrinsic::returnaddress),
 353                                 IRB.getInt32(0));
 354                         */
 355
 356                         Value * FuncName = IRB.CreateGlobalStringPtr(F.getName());
 357                         IRB.CreateCall(CDSFuncEntry, FuncName);
 358
 359                         EscapeEnumerator EE(F, "cds_cleanup", true);
 360                         while (IRBuilder<> *AtExit = EE.Next()) {
 361                           AtExit->CreateCall(CDSFuncExit, FuncName);
 362                         }
 363
 364                         Res = true;
 365                 }
 366         }
 367
 368         return false;
 369 }
 370
 371 void CDSPass::chooseInstructionsToInstrument(
 372         SmallVectorImpl<Instruction *> &Local, SmallVectorImpl<Instruction *> &All,
 373         const DataLayout &DL) {
 374         SmallPtrSet<Value*, 8> WriteTargets;
 375         // Iterate from the end.
 376         for (Instruction *I : reverse(Local)) {
 377                 if (StoreInst *Store = dyn_cast<StoreInst>(I)) {
 378                         Value *Addr = Store->getPointerOperand();
 379                         if (!shouldInstrumentReadWriteFromAddress(I->getModule(), Addr))
 380                                 continue;
 381                         WriteTargets.insert(Addr);
 382                 } else {
 383                         LoadInst *Load = cast<LoadInst>(I);
 384                         Value *Addr = Load->getPointerOperand();
 385                         if (!shouldInstrumentReadWriteFromAddress(I->getModule(), Addr))
 386                                 continue;
 387                         if (WriteTargets.count(Addr)) {
 388                                 // We will write to this temp, so no reason to analyze the read.
 389                                 NumOmittedReadsBeforeWrite++;
 390                                 continue;
 391                         }
 392                         if (addrPointsToConstantData(Addr)) {
 393                                 // Addr points to some constant data -- it can not race with any writes.
 394                                 continue;
 395                         }
 396                 }
 397                 Value *Addr = isa<StoreInst>(*I)
 398                         ? cast<StoreInst>(I)->getPointerOperand()
 399                         : cast<LoadInst>(I)->getPointerOperand();
 400                 if (isa<AllocaInst>(GetUnderlyingObject(Addr, DL)) &&
 401                                 !PointerMayBeCaptured(Addr, true, true)) {
 402                         // The variable is addressable but not captured, so it cannot be
 403                         // referenced from a different thread and participate in a data race
 404                         // (see llvm/Analysis/CaptureTracking.h for details).
 405                         NumOmittedNonCaptured++;
 406                         continue;
 407                 }
 408                 All.push_back(I);
 409         }
 410         Local.clear();
 411 }
 412
 413
 414 bool CDSPass::instrumentLoadOrStore(Instruction *I,
 415                                                                         const DataLayout &DL) {
 416         IRBuilder<> IRB(I);
 417         bool IsWrite = isa<StoreInst>(*I);
 418         Value *Addr = IsWrite
 419                 ? cast<StoreInst>(I)->getPointerOperand()
 420                 : cast<LoadInst>(I)->getPointerOperand();
 421
 422         // swifterror memory addresses are mem2reg promoted by instruction selection.
 423         // As such they cannot have regular uses like an instrumentation function and
 424         // it makes no sense to track them as memory.
 425         if (Addr->isSwiftError())
 426         return false;
 427
 428         int Idx = getMemoryAccessFuncIndex(Addr, DL);
 429
 430 //  not supported by CDS yet
 431 /*  if (IsWrite && isVtableAccess(I)) {
 432     LLVM_DEBUG(dbgs() << "  VPTR : " << *I << "\n");
 433     Value *StoredValue = cast<StoreInst>(I)->getValueOperand();
 434     // StoredValue may be a vector type if we are storing several vptrs at once.
 435     // In this case, just take the first element of the vector since this is
 436     // enough to find vptr races.
 437     if (isa<VectorType>(StoredValue->getType()))
 438       StoredValue = IRB.CreateExtractElement(
 439           StoredValue, ConstantInt::get(IRB.getInt32Ty(), 0));
 440     if (StoredValue->getType()->isIntegerTy())
 441       StoredValue = IRB.CreateIntToPtr(StoredValue, IRB.getInt8PtrTy());
 442     // Call TsanVptrUpdate.
 443     IRB.CreateCall(TsanVptrUpdate,
 444                    {IRB.CreatePointerCast(Addr, IRB.getInt8PtrTy()),
 445                     IRB.CreatePointerCast(StoredValue, IRB.getInt8PtrTy())});
 446     NumInstrumentedVtableWrites++;
 447     return true;
 448   }
 449
 450   if (!IsWrite && isVtableAccess(I)) {
 451     IRB.CreateCall(TsanVptrLoad,
 452                    IRB.CreatePointerCast(Addr, IRB.getInt8PtrTy()));
 453     NumInstrumentedVtableReads++;
 454     return true;
 455   }
 456 */
 457
 458         Value *OnAccessFunc = nullptr;
 459         OnAccessFunc = IsWrite ? CDSStore[Idx] : CDSLoad[Idx];
 460
 461         Type *ArgType = IRB.CreatePointerCast(Addr, Addr->getType())->getType();
 462
 463         if ( ArgType != Int8PtrTy && ArgType != Int16PtrTy &&
 464                         ArgType != Int32PtrTy && ArgType != Int64PtrTy ) {
 465                 // if other types of load or stores are passed in
 466                 return false;
 467         }
 468         IRB.CreateCall(OnAccessFunc, IRB.CreatePointerCast(Addr, Addr->getType()));
 469         if (IsWrite) NumInstrumentedWrites++;
 470         else         NumInstrumentedReads++;
 471         return true;
 472 }
 473
 474 bool CDSPass::instrumentAtomic(Instruction * I, const DataLayout &DL) {
 475         IRBuilder<> IRB(I);
 476
 477         // errs() << "instrumenting: " << *I << "\n";
 478
 479         if (auto *CI = dyn_cast<CallInst>(I)) {
 480                 return instrumentAtomicCall(CI, DL);
 481         }
 482
 483         Value *position = getPosition(I, IRB);
 484
 485         if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
 486                 Value *Addr = LI->getPointerOperand();
 487                 int Idx=getMemoryAccessFuncIndex(Addr, DL);
 488                 int atomic_order_index = getAtomicOrderIndex(LI->getOrdering());
 489                 Value *order = ConstantInt::get(OrdTy, atomic_order_index);
 490                 Value *args[] = {Addr, order, position};
 491                 Instruction* funcInst=CallInst::Create(CDSAtomicLoad[Idx], args);
 492                 ReplaceInstWithInst(LI, funcInst);
 493         } else if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
 494                 Value *Addr = SI->getPointerOperand();
 495                 int Idx=getMemoryAccessFuncIndex(Addr, DL);
 496                 int atomic_order_index = getAtomicOrderIndex(SI->getOrdering());
 497                 Value *val = SI->getValueOperand();
 498                 Value *order = ConstantInt::get(OrdTy, atomic_order_index);
 499                 Value *args[] = {Addr, val, order, position};
 500                 Instruction* funcInst=CallInst::Create(CDSAtomicStore[Idx], args);
 501                 ReplaceInstWithInst(SI, funcInst);
 502         } else if (AtomicRMWInst *RMWI = dyn_cast<AtomicRMWInst>(I)) {
 503                 Value *Addr = RMWI->getPointerOperand();
 504                 int Idx=getMemoryAccessFuncIndex(Addr, DL);
 505                 int atomic_order_index = getAtomicOrderIndex(RMWI->getOrdering());
 506                 Value *val = RMWI->getValOperand();
 507                 Value *order = ConstantInt::get(OrdTy, atomic_order_index);
 508                 Value *args[] = {Addr, val, order, position};
 509                 Instruction* funcInst = CallInst::Create(CDSAtomicRMW[RMWI->getOperation()][Idx], args);
 510                 ReplaceInstWithInst(RMWI, funcInst);
 511         } else if (AtomicCmpXchgInst *CASI = dyn_cast<AtomicCmpXchgInst>(I)) {
 512                 IRBuilder<> IRB(CASI);
 513
 514                 Value *Addr = CASI->getPointerOperand();
 515                 int Idx=getMemoryAccessFuncIndex(Addr, DL);
 516
 517                 const unsigned ByteSize = 1U << Idx;
 518                 const unsigned BitSize = ByteSize * 8;
 519                 Type *Ty = Type::getIntNTy(IRB.getContext(), BitSize);
 520                 Type *PtrTy = Ty->getPointerTo();
 521
 522                 Value *CmpOperand = IRB.CreateBitOrPointerCast(CASI->getCompareOperand(), Ty);
 523                 Value *NewOperand = IRB.CreateBitOrPointerCast(CASI->getNewValOperand(), Ty);
 524
 525                 int atomic_order_index_succ = getAtomicOrderIndex(CASI->getSuccessOrdering());
 526                 int atomic_order_index_fail = getAtomicOrderIndex(CASI->getFailureOrdering());
 527                 Value *order_succ = ConstantInt::get(OrdTy, atomic_order_index_succ);
 528                 Value *order_fail = ConstantInt::get(OrdTy, atomic_order_index_fail);
 529
 530                 Value *Args[] = {IRB.CreatePointerCast(Addr, PtrTy),
 531                                                  CmpOperand, NewOperand,
 532                                                  order_succ, order_fail, position};
 533
 534                 CallInst *funcInst = IRB.CreateCall(CDSAtomicCAS_V1[Idx], Args);
 535                 Value *Success = IRB.CreateICmpEQ(funcInst, CmpOperand);
 536
 537                 Value *OldVal = funcInst;
 538                 Type *OrigOldValTy = CASI->getNewValOperand()->getType();
 539                 if (Ty != OrigOldValTy) {
 540                         // The value is a pointer, so we need to cast the return value.
 541                         OldVal = IRB.CreateIntToPtr(funcInst, OrigOldValTy);
 542                 }
 543
 544                 Value *Res =
 545                   IRB.CreateInsertValue(UndefValue::get(CASI->getType()), OldVal, 0);
 546                 Res = IRB.CreateInsertValue(Res, Success, 1);
 547
 548                 I->replaceAllUsesWith(Res);
 549                 I->eraseFromParent();
 550         } else if (FenceInst *FI = dyn_cast<FenceInst>(I)) {
 551                 int atomic_order_index = getAtomicOrderIndex(FI->getOrdering());
 552                 Value *order = ConstantInt::get(OrdTy, atomic_order_index);
 553                 Value *Args[] = {order, position};
 554
 555                 CallInst *funcInst = CallInst::Create(CDSAtomicThreadFence, Args);
 556                 ReplaceInstWithInst(FI, funcInst);
 557                 // errs() << "Thread Fences replaced\n";
 558         }
 559         return true;
 560 }
 561
 562 bool CDSPass::isAtomicCall(Instruction *I) {
 563         if ( auto *CI = dyn_cast<CallInst>(I) ) {
 564                 Function *fun = CI->getCalledFunction();
 565                 if (fun == NULL)
 566                         return false;
 567
 568                 StringRef funName = fun->getName();
 569
 570                 // todo: come up with better rules for function name checking
 571                 for (StringRef name : AtomicFuncNames) {
 572                         if ( funName.contains(name) )
 573                                 return true;
 574                 }
 575
 576                 for (StringRef PartialName : PartialAtomicFuncNames) {
 577                         if (funName.contains(PartialName) &&
 578                                         funName.contains("atomic") )
 579                                 return true;
 580                 }
 581         }
 582
 583         return false;
 584 }
 585
 586 bool CDSPass::instrumentAtomicCall(CallInst *CI, const DataLayout &DL) {
 587         IRBuilder<> IRB(CI);
 588         Function *fun = CI->getCalledFunction();
 589         StringRef funName = fun->getName();
 590         std::vector<Value *> parameters;
 591
 592         User::op_iterator begin = CI->arg_begin();
 593         User::op_iterator end = CI->arg_end();
 594         for (User::op_iterator it = begin; it != end; ++it) {
 595                 Value *param = *it;
 596                 parameters.push_back(param);
 597         }
 598
 599         // obtain source line number of the CallInst
 600         Value *position = getPosition(CI, IRB);
 601
 602         // the pointer to the address is always the first argument
 603         Value *OrigPtr = parameters[0];
 604
 605         int Idx = getMemoryAccessFuncIndex(OrigPtr, DL);
 606         if (Idx < 0)
 607                 return false;
 608
 609         const unsigned ByteSize = 1U << Idx;
 610         const unsigned BitSize = ByteSize * 8;
 611         Type *Ty = Type::getIntNTy(IRB.getContext(), BitSize);
 612         Type *PtrTy = Ty->getPointerTo();
 613
 614         // atomic_init; args = {obj, order}
 615         if (funName.contains("atomic_init")) {
 616                 Value *ptr = IRB.CreatePointerCast(OrigPtr, PtrTy);
 617                 Value *val = IRB.CreateBitOrPointerCast(parameters[1], Ty);
 618                 Value *args[] = {ptr, val, position};
 619
 620                 Instruction* funcInst = CallInst::Create(CDSAtomicInit[Idx], args);
 621                 ReplaceInstWithInst(CI, funcInst);
 622
 623                 return true;
 624         }
 625
 626         // atomic_load; args = {obj, order}
 627         if (funName.contains("atomic_load")) {
 628                 bool isExplicit = funName.contains("atomic_load_explicit");
 629
 630                 Value *ptr = IRB.CreatePointerCast(OrigPtr, PtrTy);
 631                 Value *order;
 632                 if (isExplicit)
 633                         order = IRB.CreateBitOrPointerCast(parameters[1], OrdTy);
 634                 else
 635                         order = ConstantInt::get(OrdTy,
 636                                                         (int) AtomicOrderingCABI::seq_cst);
 637                 Value *args[] = {ptr, order, position};
 638
 639                 Instruction* funcInst = CallInst::Create(CDSAtomicLoad[Idx], args);
 640                 ReplaceInstWithInst(CI, funcInst);
 641
 642                 return true;
 643         } else if (funName.contains("atomic") &&
 644                                         funName.contains("load") ) {
 645                 // does this version of call always have an atomic order as an argument?
 646                 Value *ptr = IRB.CreatePointerCast(OrigPtr, PtrTy);
 647                 Value *order = IRB.CreateBitOrPointerCast(parameters[1], OrdTy);
 648                 Value *args[] = {ptr, order, position};
 649
 650                 if (!CI->getType()->isPointerTy()) {
 651                         return false;
 652                 }
 653
 654                 CallInst *funcInst = IRB.CreateCall(CDSAtomicLoad[Idx], args);
 655                 Value *RetVal = IRB.CreateIntToPtr(funcInst, CI->getType());
 656
 657                 CI->replaceAllUsesWith(RetVal);
 658                 CI->eraseFromParent();
 659
 660                 return true;
 661         }
 662
 663         // atomic_store; args = {obj, val, order}
 664         if (funName.contains("atomic_store")) {
 665                 bool isExplicit = funName.contains("atomic_store_explicit");
 666                 Value *OrigVal = parameters[1];
 667
 668                 Value *ptr = IRB.CreatePointerCast(OrigPtr, PtrTy);
 669                 Value *val = IRB.CreatePointerCast(OrigVal, Ty);
 670                 Value *order;
 671                 if (isExplicit)
 672                         order = IRB.CreateBitOrPointerCast(parameters[2], OrdTy);
 673                 else
 674                         order = ConstantInt::get(OrdTy,
 675                                                         (int) AtomicOrderingCABI::seq_cst);
 676                 Value *args[] = {ptr, val, order, position};
 677
 678                 Instruction* funcInst = CallInst::Create(CDSAtomicStore[Idx], args);
 679                 ReplaceInstWithInst(CI, funcInst);
 680
 681                 return true;
 682         } else if (funName.contains("atomic") &&
 683                                         funName.contains("EEEE5store") ) {
 684                 // does this version of call always have an atomic order as an argument?
 685                 Value *OrigVal = parameters[1];
 686
 687                 Value *ptr = IRB.CreatePointerCast(OrigPtr, PtrTy);
 688                 Value *val = IRB.CreatePointerCast(OrigVal, Ty);
 689                 Value *order = IRB.CreateBitOrPointerCast(parameters[1], OrdTy);
 690                 Value *args[] = {ptr, val, order, position};
 691
 692                 Instruction* funcInst = CallInst::Create(CDSAtomicStore[Idx], args);
 693                 ReplaceInstWithInst(CI, funcInst);
 694
 695                 return true;
 696         }
 697
 698         // atomic_fetch_*; args = {obj, val, order}
 699         if (funName.contains("atomic_fetch_") ||
 700                         funName.contains("atomic_exchange") ) {
 701                 bool isExplicit = funName.contains("_explicit");
 702                 Value *OrigVal = parameters[1];
 703
 704                 int op;
 705                 if ( funName.contains("_fetch_add") )
 706                         op = AtomicRMWInst::Add;
 707                 else if ( funName.contains("_fetch_sub") )
 708                         op = AtomicRMWInst::Sub;
 709                 else if ( funName.contains("_fetch_and") )
 710                         op = AtomicRMWInst::And;
 711                 else if ( funName.contains("_fetch_or") )
 712                         op = AtomicRMWInst::Or;
 713                 else if ( funName.contains("_fetch_xor") )
 714                         op = AtomicRMWInst::Xor;
 715                 else if ( funName.contains("atomic_exchange") )
 716                         op = AtomicRMWInst::Xchg;
 717                 else {
 718                         errs() << "Unknown atomic read-modify-write operation\n";
 719                         return false;
 720                 }
 721
 722                 Value *ptr = IRB.CreatePointerCast(OrigPtr, PtrTy);
 723                 Value *val = IRB.CreatePointerCast(OrigVal, Ty);
 724                 Value *order;
 725                 if (isExplicit)
 726                         order = IRB.CreateBitOrPointerCast(parameters[2], OrdTy);
 727                 else
 728                         order = ConstantInt::get(OrdTy,
 729                                                         (int) AtomicOrderingCABI::seq_cst);
 730                 Value *args[] = {ptr, val, order, position};
 731
 732                 Instruction* funcInst = CallInst::Create(CDSAtomicRMW[op][Idx], args);
 733                 ReplaceInstWithInst(CI, funcInst);
 734
 735                 return true;
 736         } else if (funName.contains("fetch")) {
 737                 errs() << "atomic exchange captured. Not implemented yet. ";
 738                 errs() << "See source file :";
 739                 getPosition(CI, IRB, true);
 740         } else if (funName.contains("exchange") &&
 741                         !funName.contains("compare_exchange") ) {
 742                 errs() << "atomic exchange captured. Not implemented yet. ";
 743                 errs() << "See source file :";
 744                 getPosition(CI, IRB, true);
 745         }
 746
 747         /* atomic_compare_exchange_*;
 748            args = {obj, expected, new value, order1, order2}
 749         */
 750         if ( funName.contains("atomic_compare_exchange_") ) {
 751                 bool isExplicit = funName.contains("_explicit");
 752
 753                 Value *Addr = IRB.CreatePointerCast(OrigPtr, PtrTy);
 754                 Value *CmpOperand = IRB.CreatePointerCast(parameters[1], PtrTy);
 755                 Value *NewOperand = IRB.CreateBitOrPointerCast(parameters[2], Ty);
 756
 757                 Value *order_succ, *order_fail;
 758                 if (isExplicit) {
 759                         order_succ = IRB.CreateBitOrPointerCast(parameters[3], OrdTy);
 760                         order_fail = IRB.CreateBitOrPointerCast(parameters[4], OrdTy);
 761                 } else  {
 762                         order_succ = ConstantInt::get(OrdTy,
 763                                                         (int) AtomicOrderingCABI::seq_cst);
 764                         order_fail = ConstantInt::get(OrdTy,
 765                                                         (int) AtomicOrderingCABI::seq_cst);
 766                 }
 767
 768                 Value *args[] = {Addr, CmpOperand, NewOperand,
 769                                                         order_succ, order_fail, position};
 770
 771                 Instruction* funcInst = CallInst::Create(CDSAtomicCAS_V2[Idx], args);
 772                 ReplaceInstWithInst(CI, funcInst);
 773
 774                 return true;
 775         } else if ( funName.contains("compare_exchange_strong") ||
 776                                 funName.contains("compare_exchange_weak") ) {
 777                 Value *Addr = IRB.CreatePointerCast(OrigPtr, PtrTy);
 778                 Value *CmpOperand = IRB.CreatePointerCast(parameters[1], PtrTy);
 779                 Value *NewOperand = IRB.CreateBitOrPointerCast(parameters[2], Ty);
 780
 781                 Value *order_succ, *order_fail;
 782                 order_succ = IRB.CreateBitOrPointerCast(parameters[3], OrdTy);
 783                 order_fail = IRB.CreateBitOrPointerCast(parameters[4], OrdTy);
 784
 785                 Value *args[] = {Addr, CmpOperand, NewOperand,
 786                                                         order_succ, order_fail, position};
 787                 Instruction* funcInst = CallInst::Create(CDSAtomicCAS_V2[Idx], args);
 788                 ReplaceInstWithInst(CI, funcInst);
 789
 790                 return true;
 791         }
 792
 793         return false;
 794 }
 795
 796 int CDSPass::getMemoryAccessFuncIndex(Value *Addr,
 797                                                                                 const DataLayout &DL) {
 798         Type *OrigPtrTy = Addr->getType();
 799         Type *OrigTy = cast<PointerType>(OrigPtrTy)->getElementType();
 800         assert(OrigTy->isSized());
 801         uint32_t TypeSize = DL.getTypeStoreSizeInBits(OrigTy);
 802         if (TypeSize != 8  && TypeSize != 16 &&
 803                 TypeSize != 32 && TypeSize != 64 && TypeSize != 128) {
 804                 NumAccessesWithBadSize++;
 805                 // Ignore all unusual sizes.
 806                 return -1;
 807         }
 808         size_t Idx = countTrailingZeros(TypeSize / 8);
 809         assert(Idx < kNumberOfAccessSizes);
 810         return Idx;
 811 }
 812
 813
 814 char CDSPass::ID = 0;
 815
 816 // Automatically enable the pass.
 817 static void registerCDSPass(const PassManagerBuilder &,
 818                                                         legacy::PassManagerBase &PM) {
 819         PM.add(new CDSPass());
 820 }
 821 static RegisterStandardPasses
 822         RegisterMyPass(PassManagerBuilder::EP_OptimizerLast,
 823 registerCDSPass);