tools/llvm-stress/llvm-stress.cpp

   1 //===- llvm-stress.cpp - Generate random LL files to stress-test LLVM -----===//
   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 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This program is a utility that generates random .ll files to stress-test
  10 // different components in LLVM.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/ADT/APFloat.h"
  15 #include "llvm/ADT/APInt.h"
  16 #include "llvm/ADT/ArrayRef.h"
  17 #include "llvm/ADT/STLExtras.h"
  18 #include "llvm/ADT/StringRef.h"
  19 #include "llvm/ADT/Twine.h"
  20 #include "llvm/IR/BasicBlock.h"
  21 #include "llvm/IR/CallingConv.h"
  22 #include "llvm/IR/Constants.h"
  23 #include "llvm/IR/DataLayout.h"
  24 #include "llvm/IR/DerivedTypes.h"
  25 #include "llvm/IR/Function.h"
  26 #include "llvm/IR/GlobalValue.h"
  27 #include "llvm/IR/IRPrintingPasses.h"
  28 #include "llvm/IR/InstrTypes.h"
  29 #include "llvm/IR/Instruction.h"
  30 #include "llvm/IR/Instructions.h"
  31 #include "llvm/IR/LLVMContext.h"
  32 #include "llvm/IR/LegacyPassManager.h"
  33 #include "llvm/IR/Module.h"
  34 #include "llvm/IR/Type.h"
  35 #include "llvm/IR/Value.h"
  36 #include "llvm/IR/Verifier.h"
  37 #include "llvm/Support/Casting.h"
  38 #include "llvm/Support/CommandLine.h"
  39 #include "llvm/Support/ErrorHandling.h"
  40 #include "llvm/Support/FileSystem.h"
  41 #include "llvm/Support/ManagedStatic.h"
  42 #include "llvm/Support/PrettyStackTrace.h"
  43 #include "llvm/Support/ToolOutputFile.h"
  44 #include "llvm/Support/raw_ostream.h"
  45 #include <algorithm>
  46 #include <cassert>
  47 #include <cstddef>
  48 #include <cstdint>
  49 #include <memory>
  50 #include <string>
  51 #include <system_error>
  52 #include <vector>
  53
  54 namespace llvm {
  55
  56 static cl::opt<unsigned> SeedCL("seed",
  57   cl::desc("Seed used for randomness"), cl::init(0));
  58
  59 static cl::opt<unsigned> SizeCL("size",
  60   cl::desc("The estimated size of the generated function (# of instrs)"),
  61   cl::init(100));
  62
  63 static cl::opt<std::string>
  64 OutputFilename("o", cl::desc("Override output filename"),
  65                cl::value_desc("filename"));
  66
  67 static LLVMContext Context;
  68
  69 namespace cl {
  70
  71 template <> class parser<Type*> final : public basic_parser<Type*> {
  72 public:
  73   parser(Option &O) : basic_parser(O) {}
  74
  75   // Parse options as IR types. Return true on error.
  76   bool parse(Option &O, StringRef, StringRef Arg, Type *&Value) {
  77     if      (Arg == "half")      Value = Type::getHalfTy(Context);
  78     else if (Arg == "fp128")     Value = Type::getFP128Ty(Context);
  79     else if (Arg == "x86_fp80")  Value = Type::getX86_FP80Ty(Context);
  80     else if (Arg == "ppc_fp128") Value = Type::getPPC_FP128Ty(Context);
  81     else if (Arg == "x86_mmx")   Value = Type::getX86_MMXTy(Context);
  82     else if (Arg.startswith("i")) {
  83       unsigned N = 0;
  84       Arg.drop_front().getAsInteger(10, N);
  85       if (N > 0)
  86         Value = Type::getIntNTy(Context, N);
  87     }
  88
  89     if (!Value)
  90       return O.error("Invalid IR scalar type: '" + Arg + "'!");
  91     return false;
  92   }
  93
  94   StringRef getValueName() const override { return "IR scalar type"; }
  95 };
  96
  97 } // end namespace cl
  98
  99 static cl::list<Type*> AdditionalScalarTypes("types", cl::CommaSeparated,
 100   cl::desc("Additional IR scalar types "
 101            "(always includes i1, i8, i16, i32, i64, float and double)"));
 102
 103 namespace {
 104
 105 /// A utility class to provide a pseudo-random number generator which is
 106 /// the same across all platforms. This is somewhat close to the libc
 107 /// implementation. Note: This is not a cryptographically secure pseudorandom
 108 /// number generator.
 109 class Random {
 110 public:
 111   /// C'tor
 112   Random(unsigned _seed):Seed(_seed) {}
 113
 114   /// Return a random integer, up to a
 115   /// maximum of 2**19 - 1.
 116   uint32_t Rand() {
 117     uint32_t Val = Seed + 0x000b07a1;
 118     Seed = (Val * 0x3c7c0ac1);
 119     // Only lowest 19 bits are random-ish.
 120     return Seed & 0x7ffff;
 121   }
 122
 123   /// Return a random 64 bit integer.
 124   uint64_t Rand64() {
 125     uint64_t Val = Rand() & 0xffff;
 126     Val |= uint64_t(Rand() & 0xffff) << 16;
 127     Val |= uint64_t(Rand() & 0xffff) << 32;
 128     Val |= uint64_t(Rand() & 0xffff) << 48;
 129     return Val;
 130   }
 131
 132   /// Rand operator for STL algorithms.
 133   ptrdiff_t operator()(ptrdiff_t y) {
 134     return  Rand64() % y;
 135   }
 136
 137   /// Make this like a C++11 random device
 138   using result_type = uint32_t ;
 139
 140   static constexpr result_type min() { return 0; }
 141   static constexpr result_type max() { return 0x7ffff; }
 142
 143   uint32_t operator()() {
 144     uint32_t Val = Rand();
 145     assert(Val <= max() && "Random value out of range");
 146     return Val;
 147   }
 148
 149 private:
 150   unsigned Seed;
 151 };
 152
 153 /// Generate an empty function with a default argument list.
 154 Function *GenEmptyFunction(Module *M) {
 155   // Define a few arguments
 156   LLVMContext &Context = M->getContext();
 157   Type* ArgsTy[] = {
 158     Type::getInt8PtrTy(Context),
 159     Type::getInt32PtrTy(Context),
 160     Type::getInt64PtrTy(Context),
 161     Type::getInt32Ty(Context),
 162     Type::getInt64Ty(Context),
 163     Type::getInt8Ty(Context)
 164   };
 165
 166   auto *FuncTy = FunctionType::get(Type::getVoidTy(Context), ArgsTy, false);
 167   // Pick a unique name to describe the input parameters
 168   Twine Name = "autogen_SD" + Twine{SeedCL};
 169   auto *Func = Function::Create(FuncTy, GlobalValue::ExternalLinkage, Name, M);
 170   Func->setCallingConv(CallingConv::C);
 171   return Func;
 172 }
 173
 174 /// A base class, implementing utilities needed for
 175 /// modifying and adding new random instructions.
 176 struct Modifier {
 177   /// Used to store the randomly generated values.
 178   using PieceTable = std::vector<Value *>;
 179
 180 public:
 181   /// C'tor
 182   Modifier(BasicBlock *Block, PieceTable *PT, Random *R)
 183       : BB(Block), PT(PT), Ran(R), Context(BB->getContext()) {}
 184
 185   /// virtual D'tor to silence warnings.
 186   virtual ~Modifier() = default;
 187
 188   /// Add a new instruction.
 189   virtual void Act() = 0;
 190
 191   /// Add N new instructions,
 192   virtual void ActN(unsigned n) {
 193     for (unsigned i=0; i<n; ++i)
 194       Act();
 195   }
 196
 197 protected:
 198   /// Return a random integer.
 199   uint32_t getRandom() {
 200     return Ran->Rand();
 201   }
 202
 203   /// Return a random value from the list of known values.
 204   Value *getRandomVal() {
 205     assert(PT->size());
 206     return PT->at(getRandom() % PT->size());
 207   }
 208
 209   Constant *getRandomConstant(Type *Tp) {
 210     if (Tp->isIntegerTy()) {
 211       if (getRandom() & 1)
 212         return ConstantInt::getAllOnesValue(Tp);
 213       return ConstantInt::getNullValue(Tp);
 214     } else if (Tp->isFloatingPointTy()) {
 215       if (getRandom() & 1)
 216         return ConstantFP::getAllOnesValue(Tp);
 217       return ConstantFP::getNullValue(Tp);
 218     }
 219     return UndefValue::get(Tp);
 220   }
 221
 222   /// Return a random value with a known type.
 223   Value *getRandomValue(Type *Tp) {
 224     unsigned index = getRandom();
 225     for (unsigned i=0; i<PT->size(); ++i) {
 226       Value *V = PT->at((index + i) % PT->size());
 227       if (V->getType() == Tp)
 228         return V;
 229     }
 230
 231     // If the requested type was not found, generate a constant value.
 232     if (Tp->isIntegerTy()) {
 233       if (getRandom() & 1)
 234         return ConstantInt::getAllOnesValue(Tp);
 235       return ConstantInt::getNullValue(Tp);
 236     } else if (Tp->isFloatingPointTy()) {
 237       if (getRandom() & 1)
 238         return ConstantFP::getAllOnesValue(Tp);
 239       return ConstantFP::getNullValue(Tp);
 240     } else if (Tp->isVectorTy()) {
 241       VectorType *VTp = cast<VectorType>(Tp);
 242
 243       std::vector<Constant*> TempValues;
 244       TempValues.reserve(VTp->getNumElements());
 245       for (unsigned i = 0; i < VTp->getNumElements(); ++i)
 246         TempValues.push_back(getRandomConstant(VTp->getScalarType()));
 247
 248       ArrayRef<Constant*> VectorValue(TempValues);
 249       return ConstantVector::get(VectorValue);
 250     }
 251
 252     return UndefValue::get(Tp);
 253   }
 254
 255   /// Return a random value of any pointer type.
 256   Value *getRandomPointerValue() {
 257     unsigned index = getRandom();
 258     for (unsigned i=0; i<PT->size(); ++i) {
 259       Value *V = PT->at((index + i) % PT->size());
 260       if (V->getType()->isPointerTy())
 261         return V;
 262     }
 263     return UndefValue::get(pickPointerType());
 264   }
 265
 266   /// Return a random value of any vector type.
 267   Value *getRandomVectorValue() {
 268     unsigned index = getRandom();
 269     for (unsigned i=0; i<PT->size(); ++i) {
 270       Value *V = PT->at((index + i) % PT->size());
 271       if (V->getType()->isVectorTy())
 272         return V;
 273     }
 274     return UndefValue::get(pickVectorType());
 275   }
 276
 277   /// Pick a random type.
 278   Type *pickType() {
 279     return (getRandom() & 1) ? pickVectorType() : pickScalarType();
 280   }
 281
 282   /// Pick a random pointer type.
 283   Type *pickPointerType() {
 284     Type *Ty = pickType();
 285     return PointerType::get(Ty, 0);
 286   }
 287
 288   /// Pick a random vector type.
 289   Type *pickVectorType(unsigned len = (unsigned)-1) {
 290     // Pick a random vector width in the range 2**0 to 2**4.
 291     // by adding two randoms we are generating a normal-like distribution
 292     // around 2**3.
 293     unsigned width = 1<<((getRandom() % 3) + (getRandom() % 3));
 294     Type *Ty;
 295
 296     // Vectors of x86mmx are illegal; keep trying till we get something else.
 297     do {
 298       Ty = pickScalarType();
 299     } while (Ty->isX86_MMXTy());
 300
 301     if (len != (unsigned)-1)
 302       width = len;
 303     return VectorType::get(Ty, width);
 304   }
 305
 306   /// Pick a random scalar type.
 307   Type *pickScalarType() {
 308     static std::vector<Type*> ScalarTypes;
 309     if (ScalarTypes.empty()) {
 310       ScalarTypes.assign({
 311         Type::getInt1Ty(Context),
 312         Type::getInt8Ty(Context),
 313         Type::getInt16Ty(Context),
 314         Type::getInt32Ty(Context),
 315         Type::getInt64Ty(Context),
 316         Type::getFloatTy(Context),
 317         Type::getDoubleTy(Context)
 318       });
 319       ScalarTypes.insert(ScalarTypes.end(),
 320         AdditionalScalarTypes.begin(), AdditionalScalarTypes.end());
 321     }
 322
 323     return ScalarTypes[getRandom() % ScalarTypes.size()];
 324   }
 325
 326   /// Basic block to populate
 327   BasicBlock *BB;
 328
 329   /// Value table
 330   PieceTable *PT;
 331
 332   /// Random number generator
 333   Random *Ran;
 334
 335   /// Context
 336   LLVMContext &Context;
 337 };
 338
 339 struct LoadModifier: public Modifier {
 340   LoadModifier(BasicBlock *BB, PieceTable *PT, Random *R)
 341       : Modifier(BB, PT, R) {}
 342
 343   void Act() override {
 344     // Try to use predefined pointers. If non-exist, use undef pointer value;
 345     Value *Ptr = getRandomPointerValue();
 346     Value *V = new LoadInst(Ptr, "L", BB->getTerminator());
 347     PT->push_back(V);
 348   }
 349 };
 350
 351 struct StoreModifier: public Modifier {
 352   StoreModifier(BasicBlock *BB, PieceTable *PT, Random *R)
 353       : Modifier(BB, PT, R) {}
 354
 355   void Act() override {
 356     // Try to use predefined pointers. If non-exist, use undef pointer value;
 357     Value *Ptr = getRandomPointerValue();
 358     PointerType *Tp = cast<PointerType>(Ptr->getType());
 359     Value *Val = getRandomValue(Tp->getElementType());
 360     Type  *ValTy = Val->getType();
 361
 362     // Do not store vectors of i1s because they are unsupported
 363     // by the codegen.
 364     if (ValTy->isVectorTy() && ValTy->getScalarSizeInBits() == 1)
 365       return;
 366
 367     new StoreInst(Val, Ptr, BB->getTerminator());
 368   }
 369 };
 370
 371 struct BinModifier: public Modifier {
 372   BinModifier(BasicBlock *BB, PieceTable *PT, Random *R)
 373       : Modifier(BB, PT, R) {}
 374
 375   void Act() override {
 376     Value *Val0 = getRandomVal();
 377     Value *Val1 = getRandomValue(Val0->getType());
 378
 379     // Don't handle pointer types.
 380     if (Val0->getType()->isPointerTy() ||
 381         Val1->getType()->isPointerTy())
 382       return;
 383
 384     // Don't handle i1 types.
 385     if (Val0->getType()->getScalarSizeInBits() == 1)
 386       return;
 387
 388     bool isFloat = Val0->getType()->getScalarType()->isFloatingPointTy();
 389     Instruction* Term = BB->getTerminator();
 390     unsigned R = getRandom() % (isFloat ? 7 : 13);
 391     Instruction::BinaryOps Op;
 392
 393     switch (R) {
 394     default: llvm_unreachable("Invalid BinOp");
 395     case 0:{Op = (isFloat?Instruction::FAdd : Instruction::Add); break; }
 396     case 1:{Op = (isFloat?Instruction::FSub : Instruction::Sub); break; }
 397     case 2:{Op = (isFloat?Instruction::FMul : Instruction::Mul); break; }
 398     case 3:{Op = (isFloat?Instruction::FDiv : Instruction::SDiv); break; }
 399     case 4:{Op = (isFloat?Instruction::FDiv : Instruction::UDiv); break; }
 400     case 5:{Op = (isFloat?Instruction::FRem : Instruction::SRem); break; }
 401     case 6:{Op = (isFloat?Instruction::FRem : Instruction::URem); break; }
 402     case 7: {Op = Instruction::Shl;  break; }
 403     case 8: {Op = Instruction::LShr; break; }
 404     case 9: {Op = Instruction::AShr; break; }
 405     case 10:{Op = Instruction::And;  break; }
 406     case 11:{Op = Instruction::Or;   break; }
 407     case 12:{Op = Instruction::Xor;  break; }
 408     }
 409
 410     PT->push_back(BinaryOperator::Create(Op, Val0, Val1, "B", Term));
 411   }
 412 };
 413
 414 /// Generate constant values.
 415 struct ConstModifier: public Modifier {
 416   ConstModifier(BasicBlock *BB, PieceTable *PT, Random *R)
 417       : Modifier(BB, PT, R) {}
 418
 419   void Act() override {
 420     Type *Ty = pickType();
 421
 422     if (Ty->isVectorTy()) {
 423       switch (getRandom() % 2) {
 424       case 0: if (Ty->isIntOrIntVectorTy())
 425                 return PT->push_back(ConstantVector::getAllOnesValue(Ty));
 426               break;
 427       case 1: if (Ty->isIntOrIntVectorTy())
 428                 return PT->push_back(ConstantVector::getNullValue(Ty));
 429       }
 430     }
 431
 432     if (Ty->isFloatingPointTy()) {
 433       // Generate 128 random bits, the size of the (currently)
 434       // largest floating-point types.
 435       uint64_t RandomBits[2];
 436       for (unsigned i = 0; i < 2; ++i)
 437         RandomBits[i] = Ran->Rand64();
 438
 439       APInt RandomInt(Ty->getPrimitiveSizeInBits(), makeArrayRef(RandomBits));
 440       APFloat RandomFloat(Ty->getFltSemantics(), RandomInt);
 441
 442       if (getRandom() & 1)
 443         return PT->push_back(ConstantFP::getNullValue(Ty));
 444       return PT->push_back(ConstantFP::get(Ty->getContext(), RandomFloat));
 445     }
 446
 447     if (Ty->isIntegerTy()) {
 448       switch (getRandom() % 7) {
 449       case 0:
 450         return PT->push_back(ConstantInt::get(
 451             Ty, APInt::getAllOnesValue(Ty->getPrimitiveSizeInBits())));
 452       case 1:
 453         return PT->push_back(ConstantInt::get(
 454             Ty, APInt::getNullValue(Ty->getPrimitiveSizeInBits())));
 455       case 2:
 456       case 3:
 457       case 4:
 458       case 5:
 459       case 6:
 460         PT->push_back(ConstantInt::get(Ty, getRandom()));
 461       }
 462     }
 463   }
 464 };
 465
 466 struct AllocaModifier: public Modifier {
 467   AllocaModifier(BasicBlock *BB, PieceTable *PT, Random *R)
 468       : Modifier(BB, PT, R) {}
 469
 470   void Act() override {
 471     Type *Tp = pickType();
 472     const DataLayout &DL = BB->getModule()->getDataLayout();
 473     PT->push_back(new AllocaInst(Tp, DL.getAllocaAddrSpace(),
 474                                  "A", BB->getFirstNonPHI()));
 475   }
 476 };
 477
 478 struct ExtractElementModifier: public Modifier {
 479   ExtractElementModifier(BasicBlock *BB, PieceTable *PT, Random *R)
 480       : Modifier(BB, PT, R) {}
 481
 482   void Act() override {
 483     Value *Val0 = getRandomVectorValue();
 484     Value *V = ExtractElementInst::Create(Val0,
 485              ConstantInt::get(Type::getInt32Ty(BB->getContext()),
 486              getRandom() % cast<VectorType>(Val0->getType())->getNumElements()),
 487              "E", BB->getTerminator());
 488     return PT->push_back(V);
 489   }
 490 };
 491
 492 struct ShuffModifier: public Modifier {
 493   ShuffModifier(BasicBlock *BB, PieceTable *PT, Random *R)
 494       : Modifier(BB, PT, R) {}
 495
 496   void Act() override {
 497     Value *Val0 = getRandomVectorValue();
 498     Value *Val1 = getRandomValue(Val0->getType());
 499
 500     unsigned Width = cast<VectorType>(Val0->getType())->getNumElements();
 501     std::vector<Constant*> Idxs;
 502
 503     Type *I32 = Type::getInt32Ty(BB->getContext());
 504     for (unsigned i=0; i<Width; ++i) {
 505       Constant *CI = ConstantInt::get(I32, getRandom() % (Width*2));
 506       // Pick some undef values.
 507       if (!(getRandom() % 5))
 508         CI = UndefValue::get(I32);
 509       Idxs.push_back(CI);
 510     }
 511
 512     Constant *Mask = ConstantVector::get(Idxs);
 513
 514     Value *V = new ShuffleVectorInst(Val0, Val1, Mask, "Shuff",
 515                                      BB->getTerminator());
 516     PT->push_back(V);
 517   }
 518 };
 519
 520 struct InsertElementModifier: public Modifier {
 521   InsertElementModifier(BasicBlock *BB, PieceTable *PT, Random *R)
 522       : Modifier(BB, PT, R) {}
 523
 524   void Act() override {
 525     Value *Val0 = getRandomVectorValue();
 526     Value *Val1 = getRandomValue(Val0->getType()->getScalarType());
 527
 528     Value *V = InsertElementInst::Create(Val0, Val1,
 529               ConstantInt::get(Type::getInt32Ty(BB->getContext()),
 530               getRandom() % cast<VectorType>(Val0->getType())->getNumElements()),
 531               "I",  BB->getTerminator());
 532     return PT->push_back(V);
 533   }
 534 };
 535
 536 struct CastModifier: public Modifier {
 537   CastModifier(BasicBlock *BB, PieceTable *PT, Random *R)
 538       : Modifier(BB, PT, R) {}
 539
 540   void Act() override {
 541     Value *V = getRandomVal();
 542     Type *VTy = V->getType();
 543     Type *DestTy = pickScalarType();
 544
 545     // Handle vector casts vectors.
 546     if (VTy->isVectorTy()) {
 547       VectorType *VecTy = cast<VectorType>(VTy);
 548       DestTy = pickVectorType(VecTy->getNumElements());
 549     }
 550
 551     // no need to cast.
 552     if (VTy == DestTy) return;
 553
 554     // Pointers:
 555     if (VTy->isPointerTy()) {
 556       if (!DestTy->isPointerTy())
 557         DestTy = PointerType::get(DestTy, 0);
 558       return PT->push_back(
 559         new BitCastInst(V, DestTy, "PC", BB->getTerminator()));
 560     }
 561
 562     unsigned VSize = VTy->getScalarType()->getPrimitiveSizeInBits();
 563     unsigned DestSize = DestTy->getScalarType()->getPrimitiveSizeInBits();
 564
 565     // Generate lots of bitcasts.
 566     if ((getRandom() & 1) && VSize == DestSize) {
 567       return PT->push_back(
 568         new BitCastInst(V, DestTy, "BC", BB->getTerminator()));
 569     }
 570
 571     // Both types are integers:
 572     if (VTy->isIntOrIntVectorTy() && DestTy->isIntOrIntVectorTy()) {
 573       if (VSize > DestSize) {
 574         return PT->push_back(
 575           new TruncInst(V, DestTy, "Tr", BB->getTerminator()));
 576       } else {
 577         assert(VSize < DestSize && "Different int types with the same size?");
 578         if (getRandom() & 1)
 579           return PT->push_back(
 580             new ZExtInst(V, DestTy, "ZE", BB->getTerminator()));
 581         return PT->push_back(new SExtInst(V, DestTy, "Se", BB->getTerminator()));
 582       }
 583     }
 584
 585     // Fp to int.
 586     if (VTy->isFPOrFPVectorTy() && DestTy->isIntOrIntVectorTy()) {
 587       if (getRandom() & 1)
 588         return PT->push_back(
 589           new FPToSIInst(V, DestTy, "FC", BB->getTerminator()));
 590       return PT->push_back(new FPToUIInst(V, DestTy, "FC", BB->getTerminator()));
 591     }
 592
 593     // Int to fp.
 594     if (VTy->isIntOrIntVectorTy() && DestTy->isFPOrFPVectorTy()) {
 595       if (getRandom() & 1)
 596         return PT->push_back(
 597           new SIToFPInst(V, DestTy, "FC", BB->getTerminator()));
 598       return PT->push_back(new UIToFPInst(V, DestTy, "FC", BB->getTerminator()));
 599     }
 600
 601     // Both floats.
 602     if (VTy->isFPOrFPVectorTy() && DestTy->isFPOrFPVectorTy()) {
 603       if (VSize > DestSize) {
 604         return PT->push_back(
 605           new FPTruncInst(V, DestTy, "Tr", BB->getTerminator()));
 606       } else if (VSize < DestSize) {
 607         return PT->push_back(
 608           new FPExtInst(V, DestTy, "ZE", BB->getTerminator()));
 609       }
 610       // If VSize == DestSize, then the two types must be fp128 and ppc_fp128,
 611       // for which there is no defined conversion. So do nothing.
 612     }
 613   }
 614 };
 615
 616 struct SelectModifier: public Modifier {
 617   SelectModifier(BasicBlock *BB, PieceTable *PT, Random *R)
 618       : Modifier(BB, PT, R) {}
 619
 620   void Act() override {
 621     // Try a bunch of different select configuration until a valid one is found.
 622     Value *Val0 = getRandomVal();
 623     Value *Val1 = getRandomValue(Val0->getType());
 624
 625     Type *CondTy = Type::getInt1Ty(Context);
 626
 627     // If the value type is a vector, and we allow vector select, then in 50%
 628     // of the cases generate a vector select.
 629     if (Val0->getType()->isVectorTy() && (getRandom() % 1)) {
 630       unsigned NumElem = cast<VectorType>(Val0->getType())->getNumElements();
 631       CondTy = VectorType::get(CondTy, NumElem);
 632     }
 633
 634     Value *Cond = getRandomValue(CondTy);
 635     Value *V = SelectInst::Create(Cond, Val0, Val1, "Sl", BB->getTerminator());
 636     return PT->push_back(V);
 637   }
 638 };
 639
 640 struct CmpModifier: public Modifier {
 641   CmpModifier(BasicBlock *BB, PieceTable *PT, Random *R)
 642       : Modifier(BB, PT, R) {}
 643
 644   void Act() override {
 645     Value *Val0 = getRandomVal();
 646     Value *Val1 = getRandomValue(Val0->getType());
 647
 648     if (Val0->getType()->isPointerTy()) return;
 649     bool fp = Val0->getType()->getScalarType()->isFloatingPointTy();
 650
 651     int op;
 652     if (fp) {
 653       op = getRandom() %
 654       (CmpInst::LAST_FCMP_PREDICATE - CmpInst::FIRST_FCMP_PREDICATE) +
 655        CmpInst::FIRST_FCMP_PREDICATE;
 656     } else {
 657       op = getRandom() %
 658       (CmpInst::LAST_ICMP_PREDICATE - CmpInst::FIRST_ICMP_PREDICATE) +
 659        CmpInst::FIRST_ICMP_PREDICATE;
 660     }
 661
 662     Value *V = CmpInst::Create(fp ? Instruction::FCmp : Instruction::ICmp,
 663                                (CmpInst::Predicate)op, Val0, Val1, "Cmp",
 664                                BB->getTerminator());
 665     return PT->push_back(V);
 666   }
 667 };
 668
 669 } // end anonymous namespace
 670
 671 static void FillFunction(Function *F, Random &R) {
 672   // Create a legal entry block.
 673   BasicBlock *BB = BasicBlock::Create(F->getContext(), "BB", F);
 674   ReturnInst::Create(F->getContext(), BB);
 675
 676   // Create the value table.
 677   Modifier::PieceTable PT;
 678
 679   // Consider arguments as legal values.
 680   for (auto &arg : F->args())
 681     PT.push_back(&arg);
 682
 683   // List of modifiers which add new random instructions.
 684   std::vector<std::unique_ptr<Modifier>> Modifiers;
 685   Modifiers.emplace_back(new LoadModifier(BB, &PT, &R));
 686   Modifiers.emplace_back(new StoreModifier(BB, &PT, &R));
 687   auto SM = Modifiers.back().get();
 688   Modifiers.emplace_back(new ExtractElementModifier(BB, &PT, &R));
 689   Modifiers.emplace_back(new ShuffModifier(BB, &PT, &R));
 690   Modifiers.emplace_back(new InsertElementModifier(BB, &PT, &R));
 691   Modifiers.emplace_back(new BinModifier(BB, &PT, &R));
 692   Modifiers.emplace_back(new CastModifier(BB, &PT, &R));
 693   Modifiers.emplace_back(new SelectModifier(BB, &PT, &R));
 694   Modifiers.emplace_back(new CmpModifier(BB, &PT, &R));
 695
 696   // Generate the random instructions
 697   AllocaModifier{BB, &PT, &R}.ActN(5); // Throw in a few allocas
 698   ConstModifier{BB, &PT, &R}.ActN(40); // Throw in a few constants
 699
 700   for (unsigned i = 0; i < SizeCL / Modifiers.size(); ++i)
 701     for (auto &Mod : Modifiers)
 702       Mod->Act();
 703
 704   SM->ActN(5); // Throw in a few stores.
 705 }
 706
 707 static void IntroduceControlFlow(Function *F, Random &R) {
 708   std::vector<Instruction*> BoolInst;
 709   for (auto &Instr : F->front()) {
 710     if (Instr.getType() == IntegerType::getInt1Ty(F->getContext()))
 711       BoolInst.push_back(&Instr);
 712   }
 713
 714   std::shuffle(BoolInst.begin(), BoolInst.end(), R);
 715
 716   for (auto *Instr : BoolInst) {
 717     BasicBlock *Curr = Instr->getParent();
 718     BasicBlock::iterator Loc = Instr->getIterator();
 719     BasicBlock *Next = Curr->splitBasicBlock(Loc, "CF");
 720     Instr->moveBefore(Curr->getTerminator());
 721     if (Curr != &F->getEntryBlock()) {
 722       BranchInst::Create(Curr, Next, Instr, Curr->getTerminator());
 723       Curr->getTerminator()->eraseFromParent();
 724     }
 725   }
 726 }
 727
 728 } // end namespace llvm
 729
 730 int main(int argc, char **argv) {
 731   using namespace llvm;
 732
 733   // Init LLVM, call llvm_shutdown() on exit, parse args, etc.
 734   PrettyStackTraceProgram X(argc, argv);
 735   cl::ParseCommandLineOptions(argc, argv, "llvm codegen stress-tester\n");
 736   llvm_shutdown_obj Y;
 737
 738   auto M = std::make_unique<Module>("/tmp/autogen.bc", Context);
 739   Function *F = GenEmptyFunction(M.get());
 740
 741   // Pick an initial seed value
 742   Random R(SeedCL);
 743   // Generate lots of random instructions inside a single basic block.
 744   FillFunction(F, R);
 745   // Break the basic block into many loops.
 746   IntroduceControlFlow(F, R);
 747
 748   // Figure out what stream we are supposed to write to...
 749   std::unique_ptr<ToolOutputFile> Out;
 750   // Default to standard output.
 751   if (OutputFilename.empty())
 752     OutputFilename = "-";
 753
 754   std::error_code EC;
 755   Out.reset(new ToolOutputFile(OutputFilename, EC, sys::fs::OF_None));
 756   if (EC) {
 757     errs() << EC.message() << '\n';
 758     return 1;
 759   }
 760
 761   legacy::PassManager Passes;
 762   Passes.add(createVerifierPass());
 763   Passes.add(createPrintModulePass(Out->os()));
 764   Passes.run(*M.get());
 765   Out->keep();
 766
 767   return 0;
 768 }