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                 StringRef getPassName() const override;
 119
 120         private:
 121                 void initializeCallbacks(Module &M);
 122                 bool instrumentLoadOrStore(Instruction *I, const DataLayout &DL);
 123                 bool instrumentVolatile(Instruction *I, const DataLayout &DL);
 124                 bool isAtomicCall(Instruction *I);
 125                 bool instrumentAtomic(Instruction *I, const DataLayout &DL);
 126                 bool instrumentAtomicCall(CallInst *CI, const DataLayout &DL);
 127                 void chooseInstructionsToInstrument(SmallVectorImpl<Instruction *> &Local,
 128                                                                                         SmallVectorImpl<Instruction *> &All,
 129                                                                                         const DataLayout &DL);
 130                 bool addrPointsToConstantData(Value *Addr);
 131                 int getMemoryAccessFuncIndex(Value *Addr, const DataLayout &DL);
 132
 133                 // Callbacks to run-time library are computed in doInitialization.
 134                 Constant * CDSFuncEntry;
 135                 Constant * CDSFuncExit;
 136
 137                 Constant * CDSLoad[kNumberOfAccessSizes];
 138                 Constant * CDSStore[kNumberOfAccessSizes];
 139                 Constant * CDSVolatileLoad[kNumberOfAccessSizes];
 140                 Constant * CDSVolatileStore[kNumberOfAccessSizes];
 141                 Constant * CDSAtomicInit[kNumberOfAccessSizes];
 142                 Constant * CDSAtomicLoad[kNumberOfAccessSizes];
 143                 Constant * CDSAtomicStore[kNumberOfAccessSizes];
 144                 Constant * CDSAtomicRMW[AtomicRMWInst::LAST_BINOP + 1][kNumberOfAccessSizes];
 145                 Constant * CDSAtomicCAS_V1[kNumberOfAccessSizes];
 146                 Constant * CDSAtomicCAS_V2[kNumberOfAccessSizes];
 147                 Constant * CDSAtomicThreadFence;
 148
 149                 std::vector<StringRef> AtomicFuncNames;
 150                 std::vector<StringRef> PartialAtomicFuncNames;
 151         };
 152 }
 153
 154 StringRef CDSPass::getPassName() const {
 155         return "CDSPass";
 156 }
 157
 158 static bool isVtableAccess(Instruction *I) {
 159         if (MDNode *Tag = I->getMetadata(LLVMContext::MD_tbaa))
 160                 return Tag->isTBAAVtableAccess();
 161         return false;
 162 }
 163
 164 void CDSPass::initializeCallbacks(Module &M) {
 165         LLVMContext &Ctx = M.getContext();
 166
 167         Type * Int1Ty = Type::getInt1Ty(Ctx);
 168         OrdTy = Type::getInt32Ty(Ctx);
 169
 170         Int8PtrTy  = Type::getInt8PtrTy(Ctx);
 171         Int16PtrTy = Type::getInt16PtrTy(Ctx);
 172         Int32PtrTy = Type::getInt32PtrTy(Ctx);
 173         Int64PtrTy = Type::getInt64PtrTy(Ctx);
 174
 175         VoidTy = Type::getVoidTy(Ctx);
 176
 177         CDSFuncEntry = M.getOrInsertFunction("cds_func_entry",
 178                                                                 VoidTy, Int8PtrTy);
 179         CDSFuncExit = M.getOrInsertFunction("cds_func_exit",
 180                                                                 VoidTy, Int8PtrTy);
 181
 182         // Get the function to call from our untime library.
 183         for (unsigned i = 0; i < kNumberOfAccessSizes; i++) {
 184                 const unsigned ByteSize = 1U << i;
 185                 const unsigned BitSize = ByteSize * 8;
 186
 187                 std::string ByteSizeStr = utostr(ByteSize);
 188                 std::string BitSizeStr = utostr(BitSize);
 189
 190                 Type *Ty = Type::getIntNTy(Ctx, BitSize);
 191                 Type *PtrTy = Ty->getPointerTo();
 192
 193                 // uint8_t cds_atomic_load8 (void * obj, int atomic_index)
 194                 // void cds_atomic_store8 (void * obj, int atomic_index, uint8_t val)
 195                 SmallString<32> LoadName("cds_load" + BitSizeStr);
 196                 SmallString<32> StoreName("cds_store" + BitSizeStr);
 197                 SmallString<32> VolatileLoadName("cds_volatile_load" + BitSizeStr);
 198                 SmallString<32> VolatileStoreName("cds_volatile_store" + BitSizeStr);
 199                 SmallString<32> AtomicInitName("cds_atomic_init" + BitSizeStr);
 200                 SmallString<32> AtomicLoadName("cds_atomic_load" + BitSizeStr);
 201                 SmallString<32> AtomicStoreName("cds_atomic_store" + BitSizeStr);
 202
 203                 CDSLoad[i]  = M.getOrInsertFunction(LoadName, VoidTy, PtrTy);
 204                 CDSStore[i] = M.getOrInsertFunction(StoreName, VoidTy, PtrTy);
 205                 CDSVolatileLoad[i]  = M.getOrInsertFunction(VolatileLoadName,
 206                                                                         Ty, PtrTy, Int8PtrTy);
 207                 CDSVolatileStore[i] = M.getOrInsertFunction(VolatileStoreName,
 208                                                                         VoidTy, PtrTy, Ty, Int8PtrTy);
 209                 CDSAtomicInit[i] = M.getOrInsertFunction(AtomicInitName,
 210                                                                 VoidTy, PtrTy, Ty, Int8PtrTy);
 211                 CDSAtomicLoad[i]  = M.getOrInsertFunction(AtomicLoadName,
 212                                                                 Ty, PtrTy, OrdTy, Int8PtrTy);
 213                 CDSAtomicStore[i] = M.getOrInsertFunction(AtomicStoreName,
 214                                                                 VoidTy, PtrTy, Ty, OrdTy, Int8PtrTy);
 215
 216                 for (int op = AtomicRMWInst::FIRST_BINOP;
 217                         op <= AtomicRMWInst::LAST_BINOP; ++op) {
 218                         CDSAtomicRMW[op][i] = nullptr;
 219                         std::string NamePart;
 220
 221                         if (op == AtomicRMWInst::Xchg)
 222                                 NamePart = "_exchange";
 223                         else if (op == AtomicRMWInst::Add)
 224                                 NamePart = "_fetch_add";
 225                         else if (op == AtomicRMWInst::Sub)
 226                                 NamePart = "_fetch_sub";
 227                         else if (op == AtomicRMWInst::And)
 228                                 NamePart = "_fetch_and";
 229                         else if (op == AtomicRMWInst::Or)
 230                                 NamePart = "_fetch_or";
 231                         else if (op == AtomicRMWInst::Xor)
 232                                 NamePart = "_fetch_xor";
 233                         else
 234                                 continue;
 235
 236                         SmallString<32> AtomicRMWName("cds_atomic" + NamePart + BitSizeStr);
 237                         CDSAtomicRMW[op][i] = M.getOrInsertFunction(AtomicRMWName,
 238                                                                                 Ty, PtrTy, Ty, OrdTy, Int8PtrTy);
 239                 }
 240
 241                 // only supportes strong version
 242                 SmallString<32> AtomicCASName_V1("cds_atomic_compare_exchange" + BitSizeStr + "_v1");
 243                 SmallString<32> AtomicCASName_V2("cds_atomic_compare_exchange" + BitSizeStr + "_v2");
 244                 CDSAtomicCAS_V1[i] = M.getOrInsertFunction(AtomicCASName_V1,
 245                                                                 Ty, PtrTy, Ty, Ty, OrdTy, OrdTy, Int8PtrTy);
 246                 CDSAtomicCAS_V2[i] = M.getOrInsertFunction(AtomicCASName_V2,
 247                                                                 Int1Ty, PtrTy, PtrTy, Ty, OrdTy, OrdTy, Int8PtrTy);
 248         }
 249
 250         CDSAtomicThreadFence = M.getOrInsertFunction("cds_atomic_thread_fence",
 251                                                                                                         VoidTy, OrdTy, Int8PtrTy);
 252 }
 253
 254 static bool shouldInstrumentReadWriteFromAddress(const Module *M, Value *Addr) {
 255         // Peel off GEPs and BitCasts.
 256         Addr = Addr->stripInBoundsOffsets();
 257
 258         if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Addr)) {
 259                 if (GV->hasSection()) {
 260                         StringRef SectionName = GV->getSection();
 261                         // Check if the global is in the PGO counters section.
 262                         auto OF = Triple(M->getTargetTriple()).getObjectFormat();
 263                         if (SectionName.endswith(
 264                               getInstrProfSectionName(IPSK_cnts, OF, /*AddSegmentInfo=*/false)))
 265                                 return false;
 266                 }
 267
 268                 // Check if the global is private gcov data.
 269                 if (GV->getName().startswith("__llvm_gcov") ||
 270                 GV->getName().startswith("__llvm_gcda"))
 271                 return false;
 272         }
 273
 274         // Do not instrument acesses from different address spaces; we cannot deal
 275         // with them.
 276         if (Addr) {
 277                 Type *PtrTy = cast<PointerType>(Addr->getType()->getScalarType());
 278                 if (PtrTy->getPointerAddressSpace() != 0)
 279                         return false;
 280         }
 281
 282         return true;
 283 }
 284
 285 bool CDSPass::addrPointsToConstantData(Value *Addr) {
 286         // If this is a GEP, just analyze its pointer operand.
 287         if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Addr))
 288                 Addr = GEP->getPointerOperand();
 289
 290         if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Addr)) {
 291                 if (GV->isConstant()) {
 292                         // Reads from constant globals can not race with any writes.
 293                         NumOmittedReadsFromConstantGlobals++;
 294                         return true;
 295                 }
 296         } else if (LoadInst *L = dyn_cast<LoadInst>(Addr)) {
 297                 if (isVtableAccess(L)) {
 298                         // Reads from a vtable pointer can not race with any writes.
 299                         NumOmittedReadsFromVtable++;
 300                         return true;
 301                 }
 302         }
 303         return false;
 304 }
 305
 306 bool CDSPass::runOnFunction(Function &F) {
 307         if (F.getName() == "main") {
 308                 F.setName("user_main");
 309                 errs() << "main replaced by user_main\n";
 310         }
 311
 312         if (true) {
 313                 initializeCallbacks( *F.getParent() );
 314
 315                 AtomicFuncNames =
 316                 {
 317                         "atomic_init", "atomic_load", "atomic_store",
 318                         "atomic_fetch_", "atomic_exchange", "atomic_compare_exchange_"
 319                 };
 320
 321                 PartialAtomicFuncNames =
 322                 {
 323                         "load", "store", "fetch", "exchange", "compare_exchange_"
 324                 };
 325
 326                 SmallVector<Instruction*, 8> AllLoadsAndStores;
 327                 SmallVector<Instruction*, 8> LocalLoadsAndStores;
 328                 SmallVector<Instruction*, 8> VolatileLoadsAndStores;
 329                 SmallVector<Instruction*, 8> AtomicAccesses;
 330
 331                 std::vector<Instruction *> worklist;
 332
 333                 bool Res = false;
 334                 bool HasAtomic = false;
 335                 bool HasVolatile = false;
 336                 const DataLayout &DL = F.getParent()->getDataLayout();
 337
 338                 // errs() << "--- " << F.getName() << "---\n";
 339
 340                 for (auto &B : F) {
 341                         for (auto &I : B) {
 342                                 if ( (&I)->isAtomic() || isAtomicCall(&I) ) {
 343                                         AtomicAccesses.push_back(&I);
 344                                         HasAtomic = true;
 345                                 } else if (isa<LoadInst>(I) || isa<StoreInst>(I)) {
 346                                         LoadInst *LI = dyn_cast<LoadInst>(&I);
 347                                         StoreInst *SI = dyn_cast<StoreInst>(&I);
 348                                         bool isVolatile = ( LI ? LI->isVolatile() : SI->isVolatile() );
 349
 350                                         if (isVolatile) {
 351                                                 VolatileLoadsAndStores.push_back(&I);
 352                                                 HasVolatile = true;
 353                                         } else
 354                                                 LocalLoadsAndStores.push_back(&I);
 355                                 } else if (isa<CallInst>(I) || isa<InvokeInst>(I)) {
 356                                         // not implemented yet
 357                                 }
 358                         }
 359
 360                         chooseInstructionsToInstrument(LocalLoadsAndStores, AllLoadsAndStores, DL);
 361                 }
 362
 363                 for (auto Inst : AllLoadsAndStores) {
 364                         Res |= instrumentLoadOrStore(Inst, DL);
 365                 }
 366
 367                 for (auto Inst : VolatileLoadsAndStores) {
 368                         Res |= instrumentVolatile(Inst, DL);
 369                 }
 370
 371                 for (auto Inst : AtomicAccesses) {
 372                         Res |= instrumentAtomic(Inst, DL);
 373                 }
 374
 375                 // only instrument functions that contain atomics
 376                 if (Res && ( HasAtomic || HasVolatile) ) {
 377                         IRBuilder<> IRB(F.getEntryBlock().getFirstNonPHI());
 378                         /* Unused for now
 379                         Value *ReturnAddress = IRB.CreateCall(
 380                                 Intrinsic::getDeclaration(F.getParent(), Intrinsic::returnaddress),
 381                                 IRB.getInt32(0));
 382                         */
 383
 384                         Value * FuncName = IRB.CreateGlobalStringPtr(F.getName());
 385                         IRB.CreateCall(CDSFuncEntry, FuncName);
 386
 387                         EscapeEnumerator EE(F, "cds_cleanup", true);
 388                         while (IRBuilder<> *AtExit = EE.Next()) {
 389                           AtExit->CreateCall(CDSFuncExit, FuncName);
 390                         }
 391
 392                         Res = true;
 393                 }
 394         }
 395
 396         return false;
 397 }
 398
 399 void CDSPass::chooseInstructionsToInstrument(
 400         SmallVectorImpl<Instruction *> &Local, SmallVectorImpl<Instruction *> &All,
 401         const DataLayout &DL) {
 402         SmallPtrSet<Value*, 8> WriteTargets;
 403         // Iterate from the end.
 404         for (Instruction *I : reverse(Local)) {
 405                 if (StoreInst *Store = dyn_cast<StoreInst>(I)) {
 406                         Value *Addr = Store->getPointerOperand();
 407                         if (!shouldInstrumentReadWriteFromAddress(I->getModule(), Addr))
 408                                 continue;
 409                         WriteTargets.insert(Addr);
 410                 } else {
 411                         LoadInst *Load = cast<LoadInst>(I);
 412                         Value *Addr = Load->getPointerOperand();
 413                         if (!shouldInstrumentReadWriteFromAddress(I->getModule(), Addr))
 414                                 continue;
 415                         if (WriteTargets.count(Addr)) {
 416                                 // We will write to this temp, so no reason to analyze the read.
 417                                 NumOmittedReadsBeforeWrite++;
 418                                 continue;
 419                         }
 420                         if (addrPointsToConstantData(Addr)) {
 421                                 // Addr points to some constant data -- it can not race with any writes.
 422                                 continue;
 423                         }
 424                 }
 425                 Value *Addr = isa<StoreInst>(*I)
 426                         ? cast<StoreInst>(I)->getPointerOperand()
 427                         : cast<LoadInst>(I)->getPointerOperand();
 428                 if (isa<AllocaInst>(GetUnderlyingObject(Addr, DL)) &&
 429                                 !PointerMayBeCaptured(Addr, true, true)) {
 430                         // The variable is addressable but not captured, so it cannot be
 431                         // referenced from a different thread and participate in a data race
 432                         // (see llvm/Analysis/CaptureTracking.h for details).
 433                         NumOmittedNonCaptured++;
 434                         continue;
 435                 }
 436                 All.push_back(I);
 437         }
 438         Local.clear();
 439 }
 440
 441
 442 bool CDSPass::instrumentLoadOrStore(Instruction *I,
 443                                                                         const DataLayout &DL) {
 444         IRBuilder<> IRB(I);
 445         bool IsWrite = isa<StoreInst>(*I);
 446         Value *Addr = IsWrite
 447                 ? cast<StoreInst>(I)->getPointerOperand()
 448                 : cast<LoadInst>(I)->getPointerOperand();
 449
 450         // swifterror memory addresses are mem2reg promoted by instruction selection.
 451         // As such they cannot have regular uses like an instrumentation function and
 452         // it makes no sense to track them as memory.
 453         if (Addr->isSwiftError())
 454         return false;
 455
 456         int Idx = getMemoryAccessFuncIndex(Addr, DL);
 457         if (Idx < 0)
 458                 return false;
 459
 460 //  not supported by CDS yet
 461 /*  if (IsWrite && isVtableAccess(I)) {
 462     LLVM_DEBUG(dbgs() << "  VPTR : " << *I << "\n");
 463     Value *StoredValue = cast<StoreInst>(I)->getValueOperand();
 464     // StoredValue may be a vector type if we are storing several vptrs at once.
 465     // In this case, just take the first element of the vector since this is
 466     // enough to find vptr races.
 467     if (isa<VectorType>(StoredValue->getType()))
 468       StoredValue = IRB.CreateExtractElement(
 469           StoredValue, ConstantInt::get(IRB.getInt32Ty(), 0));
 470     if (StoredValue->getType()->isIntegerTy())
 471       StoredValue = IRB.CreateIntToPtr(StoredValue, IRB.getInt8PtrTy());
 472     // Call TsanVptrUpdate.
 473     IRB.CreateCall(TsanVptrUpdate,
 474                    {IRB.CreatePointerCast(Addr, IRB.getInt8PtrTy()),
 475                     IRB.CreatePointerCast(StoredValue, IRB.getInt8PtrTy())});
 476     NumInstrumentedVtableWrites++;
 477     return true;
 478   }
 479
 480   if (!IsWrite && isVtableAccess(I)) {
 481     IRB.CreateCall(TsanVptrLoad,
 482                    IRB.CreatePointerCast(Addr, IRB.getInt8PtrTy()));
 483     NumInstrumentedVtableReads++;
 484     return true;
 485   }
 486 */
 487
 488         Value *OnAccessFunc = nullptr;
 489         OnAccessFunc = IsWrite ? CDSStore[Idx] : CDSLoad[Idx];
 490
 491         Type *ArgType = IRB.CreatePointerCast(Addr, Addr->getType())->getType();
 492
 493         if ( ArgType != Int8PtrTy && ArgType != Int16PtrTy &&
 494                         ArgType != Int32PtrTy && ArgType != Int64PtrTy ) {
 495                 // if other types of load or stores are passed in
 496                 return false;
 497         }
 498         IRB.CreateCall(OnAccessFunc, IRB.CreatePointerCast(Addr, Addr->getType()));
 499         if (IsWrite) NumInstrumentedWrites++;
 500         else         NumInstrumentedReads++;
 501         return true;
 502 }
 503
 504 bool CDSPass::instrumentVolatile(Instruction * I, const DataLayout &DL) {
 505         IRBuilder<> IRB(I);
 506         Value *position = getPosition(I, IRB);
 507
 508         if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
 509                 assert( LI->isVolatile() );
 510                 Value *Addr = LI->getPointerOperand();
 511                 int Idx=getMemoryAccessFuncIndex(Addr, DL);
 512                 if (Idx < 0)
 513                         return false;
 514
 515                 Value *args[] = {Addr, position};
 516                 Instruction* funcInst=CallInst::Create(CDSVolatileLoad[Idx], args);
 517                 ReplaceInstWithInst(LI, funcInst);
 518         } else if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
 519                 assert( SI->isVolatile() );
 520                 Value *Addr = SI->getPointerOperand();
 521                 int Idx=getMemoryAccessFuncIndex(Addr, DL);
 522                 if (Idx < 0)
 523                         return false;
 524
 525                 Value *val = SI->getValueOperand();
 526                 Value *args[] = {Addr, val, position};
 527                 Instruction* funcInst=CallInst::Create(CDSVolatileStore[Idx], args);
 528                 ReplaceInstWithInst(SI, funcInst);
 529         } else {
 530                 return false;
 531         }
 532
 533         return true;
 534 }
 535
 536 bool CDSPass::instrumentAtomic(Instruction * I, const DataLayout &DL) {
 537         IRBuilder<> IRB(I);
 538
 539         if (auto *CI = dyn_cast<CallInst>(I)) {
 540                 return instrumentAtomicCall(CI, DL);
 541         }
 542
 543         Value *position = getPosition(I, IRB);
 544
 545         if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
 546                 Value *Addr = LI->getPointerOperand();
 547                 int Idx=getMemoryAccessFuncIndex(Addr, DL);
 548                 if (Idx < 0)
 549                         return false;
 550
 551                 int atomic_order_index = getAtomicOrderIndex(LI->getOrdering());
 552                 Value *order = ConstantInt::get(OrdTy, atomic_order_index);
 553                 Value *args[] = {Addr, order, position};
 554                 Instruction* funcInst=CallInst::Create(CDSAtomicLoad[Idx], args);
 555                 ReplaceInstWithInst(LI, funcInst);
 556         } else if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
 557                 Value *Addr = SI->getPointerOperand();
 558                 int Idx=getMemoryAccessFuncIndex(Addr, DL);
 559                 if (Idx < 0)
 560                         return false;
 561
 562                 int atomic_order_index = getAtomicOrderIndex(SI->getOrdering());
 563                 Value *val = SI->getValueOperand();
 564                 Value *order = ConstantInt::get(OrdTy, atomic_order_index);
 565                 Value *args[] = {Addr, val, order, position};
 566                 Instruction* funcInst=CallInst::Create(CDSAtomicStore[Idx], args);
 567                 ReplaceInstWithInst(SI, funcInst);
 568         } else if (AtomicRMWInst *RMWI = dyn_cast<AtomicRMWInst>(I)) {
 569                 Value *Addr = RMWI->getPointerOperand();
 570                 int Idx=getMemoryAccessFuncIndex(Addr, DL);
 571                 if (Idx < 0)
 572                         return false;
 573
 574                 int atomic_order_index = getAtomicOrderIndex(RMWI->getOrdering());
 575                 Value *val = RMWI->getValOperand();
 576                 Value *order = ConstantInt::get(OrdTy, atomic_order_index);
 577                 Value *args[] = {Addr, val, order, position};
 578                 Instruction* funcInst = CallInst::Create(CDSAtomicRMW[RMWI->getOperation()][Idx], args);
 579                 ReplaceInstWithInst(RMWI, funcInst);
 580         } else if (AtomicCmpXchgInst *CASI = dyn_cast<AtomicCmpXchgInst>(I)) {
 581                 IRBuilder<> IRB(CASI);
 582
 583                 Value *Addr = CASI->getPointerOperand();
 584                 int Idx=getMemoryAccessFuncIndex(Addr, DL);
 585                 if (Idx < 0)
 586                         return false;
 587
 588                 const unsigned ByteSize = 1U << Idx;
 589                 const unsigned BitSize = ByteSize * 8;
 590                 Type *Ty = Type::getIntNTy(IRB.getContext(), BitSize);
 591                 Type *PtrTy = Ty->getPointerTo();
 592
 593                 Value *CmpOperand = IRB.CreateBitOrPointerCast(CASI->getCompareOperand(), Ty);
 594                 Value *NewOperand = IRB.CreateBitOrPointerCast(CASI->getNewValOperand(), Ty);
 595
 596                 int atomic_order_index_succ = getAtomicOrderIndex(CASI->getSuccessOrdering());
 597                 int atomic_order_index_fail = getAtomicOrderIndex(CASI->getFailureOrdering());
 598                 Value *order_succ = ConstantInt::get(OrdTy, atomic_order_index_succ);
 599                 Value *order_fail = ConstantInt::get(OrdTy, atomic_order_index_fail);
 600
 601                 Value *Args[] = {IRB.CreatePointerCast(Addr, PtrTy),
 602                                                  CmpOperand, NewOperand,
 603                                                  order_succ, order_fail, position};
 604
 605                 CallInst *funcInst = IRB.CreateCall(CDSAtomicCAS_V1[Idx], Args);
 606                 Value *Success = IRB.CreateICmpEQ(funcInst, CmpOperand);
 607
 608                 Value *OldVal = funcInst;
 609                 Type *OrigOldValTy = CASI->getNewValOperand()->getType();
 610                 if (Ty != OrigOldValTy) {
 611                         // The value is a pointer, so we need to cast the return value.
 612                         OldVal = IRB.CreateIntToPtr(funcInst, OrigOldValTy);
 613                 }
 614
 615                 Value *Res =
 616                   IRB.CreateInsertValue(UndefValue::get(CASI->getType()), OldVal, 0);
 617                 Res = IRB.CreateInsertValue(Res, Success, 1);
 618
 619                 I->replaceAllUsesWith(Res);
 620                 I->eraseFromParent();
 621         } else if (FenceInst *FI = dyn_cast<FenceInst>(I)) {
 622                 int atomic_order_index = getAtomicOrderIndex(FI->getOrdering());
 623                 Value *order = ConstantInt::get(OrdTy, atomic_order_index);
 624                 Value *Args[] = {order, position};
 625
 626                 CallInst *funcInst = CallInst::Create(CDSAtomicThreadFence, Args);
 627                 ReplaceInstWithInst(FI, funcInst);
 628                 // errs() << "Thread Fences replaced\n";
 629         }
 630         return true;
 631 }
 632
 633 bool CDSPass::isAtomicCall(Instruction *I) {
 634         if ( auto *CI = dyn_cast<CallInst>(I) ) {
 635                 Function *fun = CI->getCalledFunction();
 636                 if (fun == NULL)
 637                         return false;
 638
 639                 StringRef funName = fun->getName();
 640
 641                 // todo: come up with better rules for function name checking
 642                 for (StringRef name : AtomicFuncNames) {
 643                         if ( funName.contains(name) )
 644                                 return true;
 645                 }
 646
 647                 for (StringRef PartialName : PartialAtomicFuncNames) {
 648                         if (funName.contains(PartialName) &&
 649                                         funName.contains("atomic") )
 650                                 return true;
 651                 }
 652         }
 653
 654         return false;
 655 }
 656
 657 bool CDSPass::instrumentAtomicCall(CallInst *CI, const DataLayout &DL) {
 658         IRBuilder<> IRB(CI);
 659         Function *fun = CI->getCalledFunction();
 660         StringRef funName = fun->getName();
 661         std::vector<Value *> parameters;
 662
 663         User::op_iterator begin = CI->arg_begin();
 664         User::op_iterator end = CI->arg_end();
 665         for (User::op_iterator it = begin; it != end; ++it) {
 666                 Value *param = *it;
 667                 parameters.push_back(param);
 668         }
 669
 670         // obtain source line number of the CallInst
 671         Value *position = getPosition(CI, IRB);
 672
 673         // the pointer to the address is always the first argument
 674         Value *OrigPtr = parameters[0];
 675
 676         int Idx = getMemoryAccessFuncIndex(OrigPtr, DL);
 677         if (Idx < 0)
 678                 return false;
 679
 680         const unsigned ByteSize = 1U << Idx;
 681         const unsigned BitSize = ByteSize * 8;
 682         Type *Ty = Type::getIntNTy(IRB.getContext(), BitSize);
 683         Type *PtrTy = Ty->getPointerTo();
 684
 685         // atomic_init; args = {obj, order}
 686         if (funName.contains("atomic_init")) {
 687                 Value *OrigVal = parameters[1];
 688
 689                 Value *ptr = IRB.CreatePointerCast(OrigPtr, PtrTy);
 690                 Value *val;
 691                 if (OrigVal->getType()->isPtrOrPtrVectorTy())
 692                         val = IRB.CreatePointerCast(OrigVal, Ty);
 693                 else
 694                         val = IRB.CreateIntCast(OrigVal, Ty, true);
 695
 696                 Value *args[] = {ptr, val, position};
 697
 698                 Instruction* funcInst = CallInst::Create(CDSAtomicInit[Idx], args);
 699                 ReplaceInstWithInst(CI, funcInst);
 700
 701                 return true;
 702         }
 703
 704         // atomic_load; args = {obj, order}
 705         if (funName.contains("atomic_load")) {
 706                 bool isExplicit = funName.contains("atomic_load_explicit");
 707
 708                 Value *ptr = IRB.CreatePointerCast(OrigPtr, PtrTy);
 709                 Value *order;
 710                 if (isExplicit)
 711                         order = IRB.CreateBitOrPointerCast(parameters[1], OrdTy);
 712                 else
 713                         order = ConstantInt::get(OrdTy,
 714                                                         (int) AtomicOrderingCABI::seq_cst);
 715                 Value *args[] = {ptr, order, position};
 716
 717                 Instruction* funcInst = CallInst::Create(CDSAtomicLoad[Idx], args);
 718                 ReplaceInstWithInst(CI, funcInst);
 719
 720                 return true;
 721         } else if (funName.contains("atomic") &&
 722                                         funName.contains("load") ) {
 723                 // does this version of call always have an atomic order as an argument?
 724                 Value *ptr = IRB.CreatePointerCast(OrigPtr, PtrTy);
 725                 Value *order = IRB.CreateBitOrPointerCast(parameters[1], OrdTy);
 726                 Value *args[] = {ptr, order, position};
 727
 728                 if (!CI->getType()->isPointerTy()) {
 729                         return false;
 730                 }
 731
 732                 CallInst *funcInst = IRB.CreateCall(CDSAtomicLoad[Idx], args);
 733                 Value *RetVal = IRB.CreateIntToPtr(funcInst, CI->getType());
 734
 735                 CI->replaceAllUsesWith(RetVal);
 736                 CI->eraseFromParent();
 737
 738                 return true;
 739         }
 740
 741         // atomic_store; args = {obj, val, order}
 742         if (funName.contains("atomic_store")) {
 743                 bool isExplicit = funName.contains("atomic_store_explicit");
 744                 Value *OrigVal = parameters[1];
 745
 746                 Value *ptr = IRB.CreatePointerCast(OrigPtr, PtrTy);
 747                 Value *val = IRB.CreatePointerCast(OrigVal, Ty);
 748                 Value *order;
 749                 if (isExplicit)
 750                         order = IRB.CreateBitOrPointerCast(parameters[2], OrdTy);
 751                 else
 752                         order = ConstantInt::get(OrdTy,
 753                                                         (int) AtomicOrderingCABI::seq_cst);
 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         } else if (funName.contains("atomic") &&
 761                                         funName.contains("store") ) {
 762                 // does this version of call always have an atomic order as an argument?
 763                 Value *OrigVal = parameters[1];
 764
 765                 Value *ptr = IRB.CreatePointerCast(OrigPtr, PtrTy);
 766                 Value *val;
 767                 if (OrigVal->getType()->isPtrOrPtrVectorTy())
 768                         val = IRB.CreatePointerCast(OrigVal, Ty);
 769                 else
 770                         val = IRB.CreateIntCast(OrigVal, Ty, true);
 771
 772                 Value *order = IRB.CreateBitOrPointerCast(parameters[2], OrdTy);
 773                 Value *args[] = {ptr, val, order, position};
 774
 775                 Instruction* funcInst = CallInst::Create(CDSAtomicStore[Idx], args);
 776                 ReplaceInstWithInst(CI, funcInst);
 777
 778                 return true;
 779         }
 780
 781         // atomic_fetch_*; args = {obj, val, order}
 782         if (funName.contains("atomic_fetch_") ||
 783                 funName.contains("atomic_exchange")) {
 784
 785                 /* TODO: implement stricter function name checking */
 786                 if (funName.contains("non"))
 787                         return false;
 788
 789                 bool isExplicit = funName.contains("_explicit");
 790                 Value *OrigVal = parameters[1];
 791
 792                 int op;
 793                 if ( funName.contains("_fetch_add") )
 794                         op = AtomicRMWInst::Add;
 795                 else if ( funName.contains("_fetch_sub") )
 796                         op = AtomicRMWInst::Sub;
 797                 else if ( funName.contains("_fetch_and") )
 798                         op = AtomicRMWInst::And;
 799                 else if ( funName.contains("_fetch_or") )
 800                         op = AtomicRMWInst::Or;
 801                 else if ( funName.contains("_fetch_xor") )
 802                         op = AtomicRMWInst::Xor;
 803                 else if ( funName.contains("atomic_exchange") )
 804                         op = AtomicRMWInst::Xchg;
 805                 else {
 806                         errs() << "Unknown atomic read-modify-write operation\n";
 807                         return false;
 808                 }
 809
 810                 Value *ptr = IRB.CreatePointerCast(OrigPtr, PtrTy);
 811                 Value *val;
 812                 if (OrigVal->getType()->isPtrOrPtrVectorTy())
 813                         val = IRB.CreatePointerCast(OrigVal, Ty);
 814                 else
 815                         val = IRB.CreateIntCast(OrigVal, Ty, true);
 816
 817                 Value *order;
 818                 if (isExplicit)
 819                         order = IRB.CreateBitOrPointerCast(parameters[2], OrdTy);
 820                 else
 821                         order = ConstantInt::get(OrdTy,
 822                                                         (int) AtomicOrderingCABI::seq_cst);
 823                 Value *args[] = {ptr, val, order, position};
 824
 825                 Instruction* funcInst = CallInst::Create(CDSAtomicRMW[op][Idx], args);
 826                 ReplaceInstWithInst(CI, funcInst);
 827
 828                 return true;
 829         } else if (funName.contains("fetch")) {
 830                 errs() << "atomic exchange captured. Not implemented yet. ";
 831                 errs() << "See source file :";
 832                 getPosition(CI, IRB, true);
 833         } else if (funName.contains("exchange") &&
 834                         !funName.contains("compare_exchange") ) {
 835                 errs() << "atomic exchange captured. Not implemented yet. ";
 836                 errs() << "See source file :";
 837                 getPosition(CI, IRB, true);
 838         }
 839
 840         /* atomic_compare_exchange_*;
 841            args = {obj, expected, new value, order1, order2}
 842         */
 843         if ( funName.contains("atomic_compare_exchange_") ) {
 844                 bool isExplicit = funName.contains("_explicit");
 845
 846                 Value *Addr = IRB.CreatePointerCast(OrigPtr, PtrTy);
 847                 Value *CmpOperand = IRB.CreatePointerCast(parameters[1], PtrTy);
 848                 Value *NewOperand = IRB.CreateBitOrPointerCast(parameters[2], Ty);
 849
 850                 Value *order_succ, *order_fail;
 851                 if (isExplicit) {
 852                         order_succ = IRB.CreateBitOrPointerCast(parameters[3], OrdTy);
 853                         order_fail = IRB.CreateBitOrPointerCast(parameters[4], OrdTy);
 854                 } else  {
 855                         order_succ = ConstantInt::get(OrdTy,
 856                                                         (int) AtomicOrderingCABI::seq_cst);
 857                         order_fail = ConstantInt::get(OrdTy,
 858                                                         (int) AtomicOrderingCABI::seq_cst);
 859                 }
 860
 861                 Value *args[] = {Addr, CmpOperand, NewOperand,
 862                                                         order_succ, order_fail, position};
 863
 864                 Instruction* funcInst = CallInst::Create(CDSAtomicCAS_V2[Idx], args);
 865                 ReplaceInstWithInst(CI, funcInst);
 866
 867                 return true;
 868         } else if ( funName.contains("compare_exchange_strong") ||
 869                                 funName.contains("compare_exchange_weak") ) {
 870                 Value *Addr = IRB.CreatePointerCast(OrigPtr, PtrTy);
 871                 Value *CmpOperand = IRB.CreatePointerCast(parameters[1], PtrTy);
 872                 Value *NewOperand = IRB.CreateBitOrPointerCast(parameters[2], Ty);
 873
 874                 Value *order_succ, *order_fail;
 875                 order_succ = IRB.CreateBitOrPointerCast(parameters[3], OrdTy);
 876                 order_fail = IRB.CreateBitOrPointerCast(parameters[4], OrdTy);
 877
 878                 Value *args[] = {Addr, CmpOperand, NewOperand,
 879                                                         order_succ, order_fail, position};
 880                 Instruction* funcInst = CallInst::Create(CDSAtomicCAS_V2[Idx], args);
 881                 ReplaceInstWithInst(CI, funcInst);
 882
 883                 return true;
 884         }
 885
 886         return false;
 887 }
 888
 889 int CDSPass::getMemoryAccessFuncIndex(Value *Addr,
 890                                                                                 const DataLayout &DL) {
 891         Type *OrigPtrTy = Addr->getType();
 892         Type *OrigTy = cast<PointerType>(OrigPtrTy)->getElementType();
 893         assert(OrigTy->isSized());
 894         uint32_t TypeSize = DL.getTypeStoreSizeInBits(OrigTy);
 895         if (TypeSize != 8  && TypeSize != 16 &&
 896                 TypeSize != 32 && TypeSize != 64 && TypeSize != 128) {
 897                 NumAccessesWithBadSize++;
 898                 // Ignore all unusual sizes.
 899                 return -1;
 900         }
 901         size_t Idx = countTrailingZeros(TypeSize / 8);
 902         //assert(Idx < kNumberOfAccessSizes);
 903         if (Idx >= kNumberOfAccessSizes) {
 904                 return -1;
 905         }
 906         return Idx;
 907 }
 908
 909
 910 char CDSPass::ID = 0;
 911
 912 // Automatically enable the pass.
 913 static void registerCDSPass(const PassManagerBuilder &,
 914                                                         legacy::PassManagerBase &PM) {
 915         PM.add(new CDSPass());
 916 }
 917
 918 /* Enable the pass when opt level is greater than 0 */
 919 static RegisterStandardPasses
 920         RegisterMyPass1(PassManagerBuilder::EP_OptimizerLast,
 921 registerCDSPass);
 922
 923 /* Enable the pass when opt level is 0 */
 924 static RegisterStandardPasses
 925         RegisterMyPass2(PassManagerBuilder::EP_EnabledOnOptLevel0,
 926 registerCDSPass);