lib/ExecutionEngine/Interpreter/Execution.cpp

   1 //===-- Execution.cpp - Implement code to simulate the program ------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 //  This file contains the actual instruction interpreter.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #define DEBUG_TYPE "interpreter"
  15 #include "Interpreter.h"
  16 #include "llvm/Constants.h"
  17 #include "llvm/DerivedTypes.h"
  18 #include "llvm/Instructions.h"
  19 #include "llvm/CodeGen/IntrinsicLowering.h"
  20 #include "llvm/Support/GetElementPtrTypeIterator.h"
  21 #include "llvm/ADT/APInt.h"
  22 #include "llvm/ADT/Statistic.h"
  23 #include "llvm/Support/CommandLine.h"
  24 #include "llvm/Support/Debug.h"
  25 #include "llvm/Support/ErrorHandling.h"
  26 #include "llvm/Support/MathExtras.h"
  27 #include <algorithm>
  28 #include <cmath>
  29 using namespace llvm;
  30
  31 STATISTIC(NumDynamicInsts, "Number of dynamic instructions executed");
  32
  33 static cl::opt<bool> PrintVolatile("interpreter-print-volatile", cl::Hidden,
  34           cl::desc("make the interpreter print every volatile load and store"));
  35
  36 //===----------------------------------------------------------------------===//
  37 //                     Various Helper Functions
  38 //===----------------------------------------------------------------------===//
  39
  40 static void SetValue(Value *V, GenericValue Val, ExecutionContext &SF) {
  41   SF.Values[V] = Val;
  42 }
  43
  44 //===----------------------------------------------------------------------===//
  45 //                    Binary Instruction Implementations
  46 //===----------------------------------------------------------------------===//
  47
  48 #define IMPLEMENT_BINARY_OPERATOR(OP, TY) \
  49    case Type::TY##TyID: \
  50      Dest.TY##Val = Src1.TY##Val OP Src2.TY##Val; \
  51      break
  52
  53 static void executeFAddInst(GenericValue &Dest, GenericValue Src1,
  54                             GenericValue Src2, const Type *Ty) {
  55   switch (Ty->getTypeID()) {
  56     IMPLEMENT_BINARY_OPERATOR(+, Float);
  57     IMPLEMENT_BINARY_OPERATOR(+, Double);
  58   default:
  59     dbgs() << "Unhandled type for FAdd instruction: " << *Ty << "\n";
  60     llvm_unreachable(0);
  61   }
  62 }
  63
  64 static void executeFSubInst(GenericValue &Dest, GenericValue Src1,
  65                             GenericValue Src2, const Type *Ty) {
  66   switch (Ty->getTypeID()) {
  67     IMPLEMENT_BINARY_OPERATOR(-, Float);
  68     IMPLEMENT_BINARY_OPERATOR(-, Double);
  69   default:
  70     dbgs() << "Unhandled type for FSub instruction: " << *Ty << "\n";
  71     llvm_unreachable(0);
  72   }
  73 }
  74
  75 static void executeFMulInst(GenericValue &Dest, GenericValue Src1,
  76                             GenericValue Src2, const Type *Ty) {
  77   switch (Ty->getTypeID()) {
  78     IMPLEMENT_BINARY_OPERATOR(*, Float);
  79     IMPLEMENT_BINARY_OPERATOR(*, Double);
  80   default:
  81     dbgs() << "Unhandled type for FMul instruction: " << *Ty << "\n";
  82     llvm_unreachable(0);
  83   }
  84 }
  85
  86 static void executeFDivInst(GenericValue &Dest, GenericValue Src1,
  87                             GenericValue Src2, const Type *Ty) {
  88   switch (Ty->getTypeID()) {
  89     IMPLEMENT_BINARY_OPERATOR(/, Float);
  90     IMPLEMENT_BINARY_OPERATOR(/, Double);
  91   default:
  92     dbgs() << "Unhandled type for FDiv instruction: " << *Ty << "\n";
  93     llvm_unreachable(0);
  94   }
  95 }
  96
  97 static void executeFRemInst(GenericValue &Dest, GenericValue Src1,
  98                             GenericValue Src2, const Type *Ty) {
  99   switch (Ty->getTypeID()) {
 100   case Type::FloatTyID:
 101     Dest.FloatVal = fmod(Src1.FloatVal, Src2.FloatVal);
 102     break;
 103   case Type::DoubleTyID:
 104     Dest.DoubleVal = fmod(Src1.DoubleVal, Src2.DoubleVal);
 105     break;
 106   default:
 107     dbgs() << "Unhandled type for Rem instruction: " << *Ty << "\n";
 108     llvm_unreachable(0);
 109   }
 110 }
 111
 112 #define IMPLEMENT_INTEGER_ICMP(OP, TY) \
 113    case Type::IntegerTyID:  \
 114       Dest.IntVal = APInt(1,Src1.IntVal.OP(Src2.IntVal)); \
 115       break;
 116
 117 // Handle pointers specially because they must be compared with only as much
 118 // width as the host has.  We _do not_ want to be comparing 64 bit values when
 119 // running on a 32-bit target, otherwise the upper 32 bits might mess up
 120 // comparisons if they contain garbage.
 121 #define IMPLEMENT_POINTER_ICMP(OP) \
 122    case Type::PointerTyID: \
 123       Dest.IntVal = APInt(1,(void*)(intptr_t)Src1.PointerVal OP \
 124                             (void*)(intptr_t)Src2.PointerVal); \
 125       break;
 126
 127 static GenericValue executeICMP_EQ(GenericValue Src1, GenericValue Src2,
 128                                    const Type *Ty) {
 129   GenericValue Dest;
 130   switch (Ty->getTypeID()) {
 131     IMPLEMENT_INTEGER_ICMP(eq,Ty);
 132     IMPLEMENT_POINTER_ICMP(==);
 133   default:
 134     dbgs() << "Unhandled type for ICMP_EQ predicate: " << *Ty << "\n";
 135     llvm_unreachable(0);
 136   }
 137   return Dest;
 138 }
 139
 140 static GenericValue executeICMP_NE(GenericValue Src1, GenericValue Src2,
 141                                    const Type *Ty) {
 142   GenericValue Dest;
 143   switch (Ty->getTypeID()) {
 144     IMPLEMENT_INTEGER_ICMP(ne,Ty);
 145     IMPLEMENT_POINTER_ICMP(!=);
 146   default:
 147     dbgs() << "Unhandled type for ICMP_NE predicate: " << *Ty << "\n";
 148     llvm_unreachable(0);
 149   }
 150   return Dest;
 151 }
 152
 153 static GenericValue executeICMP_ULT(GenericValue Src1, GenericValue Src2,
 154                                     const Type *Ty) {
 155   GenericValue Dest;
 156   switch (Ty->getTypeID()) {
 157     IMPLEMENT_INTEGER_ICMP(ult,Ty);
 158     IMPLEMENT_POINTER_ICMP(<);
 159   default:
 160     dbgs() << "Unhandled type for ICMP_ULT predicate: " << *Ty << "\n";
 161     llvm_unreachable(0);
 162   }
 163   return Dest;
 164 }
 165
 166 static GenericValue executeICMP_SLT(GenericValue Src1, GenericValue Src2,
 167                                     const Type *Ty) {
 168   GenericValue Dest;
 169   switch (Ty->getTypeID()) {
 170     IMPLEMENT_INTEGER_ICMP(slt,Ty);
 171     IMPLEMENT_POINTER_ICMP(<);
 172   default:
 173     dbgs() << "Unhandled type for ICMP_SLT predicate: " << *Ty << "\n";
 174     llvm_unreachable(0);
 175   }
 176   return Dest;
 177 }
 178
 179 static GenericValue executeICMP_UGT(GenericValue Src1, GenericValue Src2,
 180                                     const Type *Ty) {
 181   GenericValue Dest;
 182   switch (Ty->getTypeID()) {
 183     IMPLEMENT_INTEGER_ICMP(ugt,Ty);
 184     IMPLEMENT_POINTER_ICMP(>);
 185   default:
 186     dbgs() << "Unhandled type for ICMP_UGT predicate: " << *Ty << "\n";
 187     llvm_unreachable(0);
 188   }
 189   return Dest;
 190 }
 191
 192 static GenericValue executeICMP_SGT(GenericValue Src1, GenericValue Src2,
 193                                     const Type *Ty) {
 194   GenericValue Dest;
 195   switch (Ty->getTypeID()) {
 196     IMPLEMENT_INTEGER_ICMP(sgt,Ty);
 197     IMPLEMENT_POINTER_ICMP(>);
 198   default:
 199     dbgs() << "Unhandled type for ICMP_SGT predicate: " << *Ty << "\n";
 200     llvm_unreachable(0);
 201   }
 202   return Dest;
 203 }
 204
 205 static GenericValue executeICMP_ULE(GenericValue Src1, GenericValue Src2,
 206                                     const Type *Ty) {
 207   GenericValue Dest;
 208   switch (Ty->getTypeID()) {
 209     IMPLEMENT_INTEGER_ICMP(ule,Ty);
 210     IMPLEMENT_POINTER_ICMP(<=);
 211   default:
 212     dbgs() << "Unhandled type for ICMP_ULE predicate: " << *Ty << "\n";
 213     llvm_unreachable(0);
 214   }
 215   return Dest;
 216 }
 217
 218 static GenericValue executeICMP_SLE(GenericValue Src1, GenericValue Src2,
 219                                     const Type *Ty) {
 220   GenericValue Dest;
 221   switch (Ty->getTypeID()) {
 222     IMPLEMENT_INTEGER_ICMP(sle,Ty);
 223     IMPLEMENT_POINTER_ICMP(<=);
 224   default:
 225     dbgs() << "Unhandled type for ICMP_SLE predicate: " << *Ty << "\n";
 226     llvm_unreachable(0);
 227   }
 228   return Dest;
 229 }
 230
 231 static GenericValue executeICMP_UGE(GenericValue Src1, GenericValue Src2,
 232                                     const Type *Ty) {
 233   GenericValue Dest;
 234   switch (Ty->getTypeID()) {
 235     IMPLEMENT_INTEGER_ICMP(uge,Ty);
 236     IMPLEMENT_POINTER_ICMP(>=);
 237   default:
 238     dbgs() << "Unhandled type for ICMP_UGE predicate: " << *Ty << "\n";
 239     llvm_unreachable(0);
 240   }
 241   return Dest;
 242 }
 243
 244 static GenericValue executeICMP_SGE(GenericValue Src1, GenericValue Src2,
 245                                     const Type *Ty) {
 246   GenericValue Dest;
 247   switch (Ty->getTypeID()) {
 248     IMPLEMENT_INTEGER_ICMP(sge,Ty);
 249     IMPLEMENT_POINTER_ICMP(>=);
 250   default:
 251     dbgs() << "Unhandled type for ICMP_SGE predicate: " << *Ty << "\n";
 252     llvm_unreachable(0);
 253   }
 254   return Dest;
 255 }
 256
 257 void Interpreter::visitICmpInst(ICmpInst &I) {
 258   ExecutionContext &SF = ECStack.back();
 259   const Type *Ty    = I.getOperand(0)->getType();
 260   GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
 261   GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
 262   GenericValue R;   // Result
 263
 264   switch (I.getPredicate()) {
 265   case ICmpInst::ICMP_EQ:  R = executeICMP_EQ(Src1,  Src2, Ty); break;
 266   case ICmpInst::ICMP_NE:  R = executeICMP_NE(Src1,  Src2, Ty); break;
 267   case ICmpInst::ICMP_ULT: R = executeICMP_ULT(Src1, Src2, Ty); break;
 268   case ICmpInst::ICMP_SLT: R = executeICMP_SLT(Src1, Src2, Ty); break;
 269   case ICmpInst::ICMP_UGT: R = executeICMP_UGT(Src1, Src2, Ty); break;
 270   case ICmpInst::ICMP_SGT: R = executeICMP_SGT(Src1, Src2, Ty); break;
 271   case ICmpInst::ICMP_ULE: R = executeICMP_ULE(Src1, Src2, Ty); break;
 272   case ICmpInst::ICMP_SLE: R = executeICMP_SLE(Src1, Src2, Ty); break;
 273   case ICmpInst::ICMP_UGE: R = executeICMP_UGE(Src1, Src2, Ty); break;
 274   case ICmpInst::ICMP_SGE: R = executeICMP_SGE(Src1, Src2, Ty); break;
 275   default:
 276     dbgs() << "Don't know how to handle this ICmp predicate!\n-->" << I;
 277     llvm_unreachable(0);
 278   }
 279
 280   SetValue(&I, R, SF);
 281 }
 282
 283 #define IMPLEMENT_FCMP(OP, TY) \
 284    case Type::TY##TyID: \
 285      Dest.IntVal = APInt(1,Src1.TY##Val OP Src2.TY##Val); \
 286      break
 287
 288 static GenericValue executeFCMP_OEQ(GenericValue Src1, GenericValue Src2,
 289                                    const Type *Ty) {
 290   GenericValue Dest;
 291   switch (Ty->getTypeID()) {
 292     IMPLEMENT_FCMP(==, Float);
 293     IMPLEMENT_FCMP(==, Double);
 294   default:
 295     dbgs() << "Unhandled type for FCmp EQ instruction: " << *Ty << "\n";
 296     llvm_unreachable(0);
 297   }
 298   return Dest;
 299 }
 300
 301 static GenericValue executeFCMP_ONE(GenericValue Src1, GenericValue Src2,
 302                                    const Type *Ty) {
 303   GenericValue Dest;
 304   switch (Ty->getTypeID()) {
 305     IMPLEMENT_FCMP(!=, Float);
 306     IMPLEMENT_FCMP(!=, Double);
 307
 308   default:
 309     dbgs() << "Unhandled type for FCmp NE instruction: " << *Ty << "\n";
 310     llvm_unreachable(0);
 311   }
 312   return Dest;
 313 }
 314
 315 static GenericValue executeFCMP_OLE(GenericValue Src1, GenericValue Src2,
 316                                    const Type *Ty) {
 317   GenericValue Dest;
 318   switch (Ty->getTypeID()) {
 319     IMPLEMENT_FCMP(<=, Float);
 320     IMPLEMENT_FCMP(<=, Double);
 321   default:
 322     dbgs() << "Unhandled type for FCmp LE instruction: " << *Ty << "\n";
 323     llvm_unreachable(0);
 324   }
 325   return Dest;
 326 }
 327
 328 static GenericValue executeFCMP_OGE(GenericValue Src1, GenericValue Src2,
 329                                    const Type *Ty) {
 330   GenericValue Dest;
 331   switch (Ty->getTypeID()) {
 332     IMPLEMENT_FCMP(>=, Float);
 333     IMPLEMENT_FCMP(>=, Double);
 334   default:
 335     dbgs() << "Unhandled type for FCmp GE instruction: " << *Ty << "\n";
 336     llvm_unreachable(0);
 337   }
 338   return Dest;
 339 }
 340
 341 static GenericValue executeFCMP_OLT(GenericValue Src1, GenericValue Src2,
 342                                    const Type *Ty) {
 343   GenericValue Dest;
 344   switch (Ty->getTypeID()) {
 345     IMPLEMENT_FCMP(<, Float);
 346     IMPLEMENT_FCMP(<, Double);
 347   default:
 348     dbgs() << "Unhandled type for FCmp LT instruction: " << *Ty << "\n";
 349     llvm_unreachable(0);
 350   }
 351   return Dest;
 352 }
 353
 354 static GenericValue executeFCMP_OGT(GenericValue Src1, GenericValue Src2,
 355                                      const Type *Ty) {
 356   GenericValue Dest;
 357   switch (Ty->getTypeID()) {
 358     IMPLEMENT_FCMP(>, Float);
 359     IMPLEMENT_FCMP(>, Double);
 360   default:
 361     dbgs() << "Unhandled type for FCmp GT instruction: " << *Ty << "\n";
 362     llvm_unreachable(0);
 363   }
 364   return Dest;
 365 }
 366
 367 #define IMPLEMENT_UNORDERED(TY, X,Y)                                     \
 368   if (TY->isFloatTy()) {                                                 \
 369     if (X.FloatVal != X.FloatVal || Y.FloatVal != Y.FloatVal) {          \
 370       Dest.IntVal = APInt(1,true);                                       \
 371       return Dest;                                                       \
 372     }                                                                    \
 373   } else if (X.DoubleVal != X.DoubleVal || Y.DoubleVal != Y.DoubleVal) { \
 374     Dest.IntVal = APInt(1,true);                                         \
 375     return Dest;                                                         \
 376   }
 377
 378
 379 static GenericValue executeFCMP_UEQ(GenericValue Src1, GenericValue Src2,
 380                                    const Type *Ty) {
 381   GenericValue Dest;
 382   IMPLEMENT_UNORDERED(Ty, Src1, Src2)
 383   return executeFCMP_OEQ(Src1, Src2, Ty);
 384 }
 385
 386 static GenericValue executeFCMP_UNE(GenericValue Src1, GenericValue Src2,
 387                                    const Type *Ty) {
 388   GenericValue Dest;
 389   IMPLEMENT_UNORDERED(Ty, Src1, Src2)
 390   return executeFCMP_ONE(Src1, Src2, Ty);
 391 }
 392
 393 static GenericValue executeFCMP_ULE(GenericValue Src1, GenericValue Src2,
 394                                    const Type *Ty) {
 395   GenericValue Dest;
 396   IMPLEMENT_UNORDERED(Ty, Src1, Src2)
 397   return executeFCMP_OLE(Src1, Src2, Ty);
 398 }
 399
 400 static GenericValue executeFCMP_UGE(GenericValue Src1, GenericValue Src2,
 401                                    const Type *Ty) {
 402   GenericValue Dest;
 403   IMPLEMENT_UNORDERED(Ty, Src1, Src2)
 404   return executeFCMP_OGE(Src1, Src2, Ty);
 405 }
 406
 407 static GenericValue executeFCMP_ULT(GenericValue Src1, GenericValue Src2,
 408                                    const Type *Ty) {
 409   GenericValue Dest;
 410   IMPLEMENT_UNORDERED(Ty, Src1, Src2)
 411   return executeFCMP_OLT(Src1, Src2, Ty);
 412 }
 413
 414 static GenericValue executeFCMP_UGT(GenericValue Src1, GenericValue Src2,
 415                                      const Type *Ty) {
 416   GenericValue Dest;
 417   IMPLEMENT_UNORDERED(Ty, Src1, Src2)
 418   return executeFCMP_OGT(Src1, Src2, Ty);
 419 }
 420
 421 static GenericValue executeFCMP_ORD(GenericValue Src1, GenericValue Src2,
 422                                      const Type *Ty) {
 423   GenericValue Dest;
 424   if (Ty->isFloatTy())
 425     Dest.IntVal = APInt(1,(Src1.FloatVal == Src1.FloatVal &&
 426                            Src2.FloatVal == Src2.FloatVal));
 427   else
 428     Dest.IntVal = APInt(1,(Src1.DoubleVal == Src1.DoubleVal &&
 429                            Src2.DoubleVal == Src2.DoubleVal));
 430   return Dest;
 431 }
 432
 433 static GenericValue executeFCMP_UNO(GenericValue Src1, GenericValue Src2,
 434                                      const Type *Ty) {
 435   GenericValue Dest;
 436   if (Ty->isFloatTy())
 437     Dest.IntVal = APInt(1,(Src1.FloatVal != Src1.FloatVal ||
 438                            Src2.FloatVal != Src2.FloatVal));
 439   else
 440     Dest.IntVal = APInt(1,(Src1.DoubleVal != Src1.DoubleVal ||
 441                            Src2.DoubleVal != Src2.DoubleVal));
 442   return Dest;
 443 }
 444
 445 void Interpreter::visitFCmpInst(FCmpInst &I) {
 446   ExecutionContext &SF = ECStack.back();
 447   const Type *Ty    = I.getOperand(0)->getType();
 448   GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
 449   GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
 450   GenericValue R;   // Result
 451
 452   switch (I.getPredicate()) {
 453   case FCmpInst::FCMP_FALSE: R.IntVal = APInt(1,false); break;
 454   case FCmpInst::FCMP_TRUE:  R.IntVal = APInt(1,true); break;
 455   case FCmpInst::FCMP_ORD:   R = executeFCMP_ORD(Src1, Src2, Ty); break;
 456   case FCmpInst::FCMP_UNO:   R = executeFCMP_UNO(Src1, Src2, Ty); break;
 457   case FCmpInst::FCMP_UEQ:   R = executeFCMP_UEQ(Src1, Src2, Ty); break;
 458   case FCmpInst::FCMP_OEQ:   R = executeFCMP_OEQ(Src1, Src2, Ty); break;
 459   case FCmpInst::FCMP_UNE:   R = executeFCMP_UNE(Src1, Src2, Ty); break;
 460   case FCmpInst::FCMP_ONE:   R = executeFCMP_ONE(Src1, Src2, Ty); break;
 461   case FCmpInst::FCMP_ULT:   R = executeFCMP_ULT(Src1, Src2, Ty); break;
 462   case FCmpInst::FCMP_OLT:   R = executeFCMP_OLT(Src1, Src2, Ty); break;
 463   case FCmpInst::FCMP_UGT:   R = executeFCMP_UGT(Src1, Src2, Ty); break;
 464   case FCmpInst::FCMP_OGT:   R = executeFCMP_OGT(Src1, Src2, Ty); break;
 465   case FCmpInst::FCMP_ULE:   R = executeFCMP_ULE(Src1, Src2, Ty); break;
 466   case FCmpInst::FCMP_OLE:   R = executeFCMP_OLE(Src1, Src2, Ty); break;
 467   case FCmpInst::FCMP_UGE:   R = executeFCMP_UGE(Src1, Src2, Ty); break;
 468   case FCmpInst::FCMP_OGE:   R = executeFCMP_OGE(Src1, Src2, Ty); break;
 469   default:
 470     dbgs() << "Don't know how to handle this FCmp predicate!\n-->" << I;
 471     llvm_unreachable(0);
 472   }
 473
 474   SetValue(&I, R, SF);
 475 }
 476
 477 static GenericValue executeCmpInst(unsigned predicate, GenericValue Src1,
 478                                    GenericValue Src2, const Type *Ty) {
 479   GenericValue Result;
 480   switch (predicate) {
 481   case ICmpInst::ICMP_EQ:    return executeICMP_EQ(Src1, Src2, Ty);
 482   case ICmpInst::ICMP_NE:    return executeICMP_NE(Src1, Src2, Ty);
 483   case ICmpInst::ICMP_UGT:   return executeICMP_UGT(Src1, Src2, Ty);
 484   case ICmpInst::ICMP_SGT:   return executeICMP_SGT(Src1, Src2, Ty);
 485   case ICmpInst::ICMP_ULT:   return executeICMP_ULT(Src1, Src2, Ty);
 486   case ICmpInst::ICMP_SLT:   return executeICMP_SLT(Src1, Src2, Ty);
 487   case ICmpInst::ICMP_UGE:   return executeICMP_UGE(Src1, Src2, Ty);
 488   case ICmpInst::ICMP_SGE:   return executeICMP_SGE(Src1, Src2, Ty);
 489   case ICmpInst::ICMP_ULE:   return executeICMP_ULE(Src1, Src2, Ty);
 490   case ICmpInst::ICMP_SLE:   return executeICMP_SLE(Src1, Src2, Ty);
 491   case FCmpInst::FCMP_ORD:   return executeFCMP_ORD(Src1, Src2, Ty);
 492   case FCmpInst::FCMP_UNO:   return executeFCMP_UNO(Src1, Src2, Ty);
 493   case FCmpInst::FCMP_OEQ:   return executeFCMP_OEQ(Src1, Src2, Ty);
 494   case FCmpInst::FCMP_UEQ:   return executeFCMP_UEQ(Src1, Src2, Ty);
 495   case FCmpInst::FCMP_ONE:   return executeFCMP_ONE(Src1, Src2, Ty);
 496   case FCmpInst::FCMP_UNE:   return executeFCMP_UNE(Src1, Src2, Ty);
 497   case FCmpInst::FCMP_OLT:   return executeFCMP_OLT(Src1, Src2, Ty);
 498   case FCmpInst::FCMP_ULT:   return executeFCMP_ULT(Src1, Src2, Ty);
 499   case FCmpInst::FCMP_OGT:   return executeFCMP_OGT(Src1, Src2, Ty);
 500   case FCmpInst::FCMP_UGT:   return executeFCMP_UGT(Src1, Src2, Ty);
 501   case FCmpInst::FCMP_OLE:   return executeFCMP_OLE(Src1, Src2, Ty);
 502   case FCmpInst::FCMP_ULE:   return executeFCMP_ULE(Src1, Src2, Ty);
 503   case FCmpInst::FCMP_OGE:   return executeFCMP_OGE(Src1, Src2, Ty);
 504   case FCmpInst::FCMP_UGE:   return executeFCMP_UGE(Src1, Src2, Ty);
 505   case FCmpInst::FCMP_FALSE: {
 506     GenericValue Result;
 507     Result.IntVal = APInt(1, false);
 508     return Result;
 509   }
 510   case FCmpInst::FCMP_TRUE: {
 511     GenericValue Result;
 512     Result.IntVal = APInt(1, true);
 513     return Result;
 514   }
 515   default:
 516     dbgs() << "Unhandled Cmp predicate\n";
 517     llvm_unreachable(0);
 518   }
 519 }
 520
 521 void Interpreter::visitBinaryOperator(BinaryOperator &I) {
 522   ExecutionContext &SF = ECStack.back();
 523   const Type *Ty    = I.getOperand(0)->getType();
 524   GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
 525   GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
 526   GenericValue R;   // Result
 527
 528   switch (I.getOpcode()) {
 529   case Instruction::Add:   R.IntVal = Src1.IntVal + Src2.IntVal; break;
 530   case Instruction::Sub:   R.IntVal = Src1.IntVal - Src2.IntVal; break;
 531   case Instruction::Mul:   R.IntVal = Src1.IntVal * Src2.IntVal; break;
 532   case Instruction::FAdd:  executeFAddInst(R, Src1, Src2, Ty); break;
 533   case Instruction::FSub:  executeFSubInst(R, Src1, Src2, Ty); break;
 534   case Instruction::FMul:  executeFMulInst(R, Src1, Src2, Ty); break;
 535   case Instruction::FDiv:  executeFDivInst(R, Src1, Src2, Ty); break;
 536   case Instruction::FRem:  executeFRemInst(R, Src1, Src2, Ty); break;
 537   case Instruction::UDiv:  R.IntVal = Src1.IntVal.udiv(Src2.IntVal); break;
 538   case Instruction::SDiv:  R.IntVal = Src1.IntVal.sdiv(Src2.IntVal); break;
 539   case Instruction::URem:  R.IntVal = Src1.IntVal.urem(Src2.IntVal); break;
 540   case Instruction::SRem:  R.IntVal = Src1.IntVal.srem(Src2.IntVal); break;
 541   case Instruction::And:   R.IntVal = Src1.IntVal & Src2.IntVal; break;
 542   case Instruction::Or:    R.IntVal = Src1.IntVal | Src2.IntVal; break;
 543   case Instruction::Xor:   R.IntVal = Src1.IntVal ^ Src2.IntVal; break;
 544   default:
 545     dbgs() << "Don't know how to handle this binary operator!\n-->" << I;
 546     llvm_unreachable(0);
 547   }
 548
 549   SetValue(&I, R, SF);
 550 }
 551
 552 static GenericValue executeSelectInst(GenericValue Src1, GenericValue Src2,
 553                                       GenericValue Src3) {
 554   return Src1.IntVal == 0 ? Src3 : Src2;
 555 }
 556
 557 void Interpreter::visitSelectInst(SelectInst &I) {
 558   ExecutionContext &SF = ECStack.back();
 559   GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
 560   GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
 561   GenericValue Src3 = getOperandValue(I.getOperand(2), SF);
 562   GenericValue R = executeSelectInst(Src1, Src2, Src3);
 563   SetValue(&I, R, SF);
 564 }
 565
 566
 567 //===----------------------------------------------------------------------===//
 568 //                     Terminator Instruction Implementations
 569 //===----------------------------------------------------------------------===//
 570
 571 void Interpreter::exitCalled(GenericValue GV) {
 572   // runAtExitHandlers() assumes there are no stack frames, but
 573   // if exit() was called, then it had a stack frame. Blow away
 574   // the stack before interpreting atexit handlers.
 575   ECStack.clear();
 576   runAtExitHandlers();
 577   exit(GV.IntVal.zextOrTrunc(32).getZExtValue());
 578 }
 579
 580 /// Pop the last stack frame off of ECStack and then copy the result
 581 /// back into the result variable if we are not returning void. The
 582 /// result variable may be the ExitValue, or the Value of the calling
 583 /// CallInst if there was a previous stack frame. This method may
 584 /// invalidate any ECStack iterators you have. This method also takes
 585 /// care of switching to the normal destination BB, if we are returning
 586 /// from an invoke.
 587 ///
 588 void Interpreter::popStackAndReturnValueToCaller(const Type *RetTy,
 589                                                  GenericValue Result) {
 590   // Pop the current stack frame.
 591   ECStack.pop_back();
 592
 593   if (ECStack.empty()) {  // Finished main.  Put result into exit code...
 594     if (RetTy && !RetTy->isVoidTy()) {          // Nonvoid return type?
 595       ExitValue = Result;   // Capture the exit value of the program
 596     } else {
 597       memset(&ExitValue.Untyped, 0, sizeof(ExitValue.Untyped));
 598     }
 599   } else {
 600     // If we have a previous stack frame, and we have a previous call,
 601     // fill in the return value...
 602     ExecutionContext &CallingSF = ECStack.back();
 603     if (Instruction *I = CallingSF.Caller.getInstruction()) {
 604       // Save result...
 605       if (!CallingSF.Caller.getType()->isVoidTy())
 606         SetValue(I, Result, CallingSF);
 607       if (InvokeInst *II = dyn_cast<InvokeInst> (I))
 608         SwitchToNewBasicBlock (II->getNormalDest (), CallingSF);
 609       CallingSF.Caller = CallSite();          // We returned from the call...
 610     }
 611   }
 612 }
 613
 614 void Interpreter::visitReturnInst(ReturnInst &I) {
 615   ExecutionContext &SF = ECStack.back();
 616   const Type *RetTy = Type::getVoidTy(I.getContext());
 617   GenericValue Result;
 618
 619   // Save away the return value... (if we are not 'ret void')
 620   if (I.getNumOperands()) {
 621     RetTy  = I.getReturnValue()->getType();
 622     Result = getOperandValue(I.getReturnValue(), SF);
 623   }
 624
 625   popStackAndReturnValueToCaller(RetTy, Result);
 626 }
 627
 628 void Interpreter::visitUnwindInst(UnwindInst &I) {
 629   // Unwind stack
 630   Instruction *Inst;
 631   do {
 632     ECStack.pop_back();
 633     if (ECStack.empty())
 634       report_fatal_error("Empty stack during unwind!");
 635     Inst = ECStack.back().Caller.getInstruction();
 636   } while (!(Inst && isa<InvokeInst>(Inst)));
 637
 638   // Return from invoke
 639   ExecutionContext &InvokingSF = ECStack.back();
 640   InvokingSF.Caller = CallSite();
 641
 642   // Go to exceptional destination BB of invoke instruction
 643   SwitchToNewBasicBlock(cast<InvokeInst>(Inst)->getUnwindDest(), InvokingSF);
 644 }
 645
 646 void Interpreter::visitUnreachableInst(UnreachableInst &I) {
 647   report_fatal_error("Program executed an 'unreachable' instruction!");
 648 }
 649
 650 void Interpreter::visitBranchInst(BranchInst &I) {
 651   ExecutionContext &SF = ECStack.back();
 652   BasicBlock *Dest;
 653
 654   Dest = I.getSuccessor(0);          // Uncond branches have a fixed dest...
 655   if (!I.isUnconditional()) {
 656     Value *Cond = I.getCondition();
 657     if (getOperandValue(Cond, SF).IntVal == 0) // If false cond...
 658       Dest = I.getSuccessor(1);
 659   }
 660   SwitchToNewBasicBlock(Dest, SF);
 661 }
 662
 663 void Interpreter::visitSwitchInst(SwitchInst &I) {
 664   ExecutionContext &SF = ECStack.back();
 665   GenericValue CondVal = getOperandValue(I.getOperand(0), SF);
 666   const Type *ElTy = I.getOperand(0)->getType();
 667
 668   // Check to see if any of the cases match...
 669   BasicBlock *Dest = 0;
 670   for (unsigned i = 2, e = I.getNumOperands(); i != e; i += 2)
 671     if (executeICMP_EQ(CondVal, getOperandValue(I.getOperand(i), SF), ElTy)
 672         .IntVal != 0) {
 673       Dest = cast<BasicBlock>(I.getOperand(i+1));
 674       break;
 675     }
 676
 677   if (!Dest) Dest = I.getDefaultDest();   // No cases matched: use default
 678   SwitchToNewBasicBlock(Dest, SF);
 679 }
 680
 681 void Interpreter::visitIndirectBrInst(IndirectBrInst &I) {
 682   ExecutionContext &SF = ECStack.back();
 683   void *Dest = GVTOP(getOperandValue(I.getAddress(), SF));
 684   SwitchToNewBasicBlock((BasicBlock*)Dest, SF);
 685 }
 686
 687
 688 // SwitchToNewBasicBlock - This method is used to jump to a new basic block.
 689 // This function handles the actual updating of block and instruction iterators
 690 // as well as execution of all of the PHI nodes in the destination block.
 691 //
 692 // This method does this because all of the PHI nodes must be executed
 693 // atomically, reading their inputs before any of the results are updated.  Not
 694 // doing this can cause problems if the PHI nodes depend on other PHI nodes for
 695 // their inputs.  If the input PHI node is updated before it is read, incorrect
 696 // results can happen.  Thus we use a two phase approach.
 697 //
 698 void Interpreter::SwitchToNewBasicBlock(BasicBlock *Dest, ExecutionContext &SF){
 699   BasicBlock *PrevBB = SF.CurBB;      // Remember where we came from...
 700   SF.CurBB   = Dest;                  // Update CurBB to branch destination
 701   SF.CurInst = SF.CurBB->begin();     // Update new instruction ptr...
 702
 703   if (!isa<PHINode>(SF.CurInst)) return;  // Nothing fancy to do
 704
 705   // Loop over all of the PHI nodes in the current block, reading their inputs.
 706   std::vector<GenericValue> ResultValues;
 707
 708   for (; PHINode *PN = dyn_cast<PHINode>(SF.CurInst); ++SF.CurInst) {
 709     // Search for the value corresponding to this previous bb...
 710     int i = PN->getBasicBlockIndex(PrevBB);
 711     assert(i != -1 && "PHINode doesn't contain entry for predecessor??");
 712     Value *IncomingValue = PN->getIncomingValue(i);
 713
 714     // Save the incoming value for this PHI node...
 715     ResultValues.push_back(getOperandValue(IncomingValue, SF));
 716   }
 717
 718   // Now loop over all of the PHI nodes setting their values...
 719   SF.CurInst = SF.CurBB->begin();
 720   for (unsigned i = 0; isa<PHINode>(SF.CurInst); ++SF.CurInst, ++i) {
 721     PHINode *PN = cast<PHINode>(SF.CurInst);
 722     SetValue(PN, ResultValues[i], SF);
 723   }
 724 }
 725
 726 //===----------------------------------------------------------------------===//
 727 //                     Memory Instruction Implementations
 728 //===----------------------------------------------------------------------===//
 729
 730 void Interpreter::visitAllocaInst(AllocaInst &I) {
 731   ExecutionContext &SF = ECStack.back();
 732
 733   const Type *Ty = I.getType()->getElementType();  // Type to be allocated
 734
 735   // Get the number of elements being allocated by the array...
 736   unsigned NumElements =
 737     getOperandValue(I.getOperand(0), SF).IntVal.getZExtValue();
 738
 739   unsigned TypeSize = (size_t)TD.getTypeAllocSize(Ty);
 740
 741   // Avoid malloc-ing zero bytes, use max()...
 742   unsigned MemToAlloc = std::max(1U, NumElements * TypeSize);
 743
 744   // Allocate enough memory to hold the type...
 745   void *Memory = malloc(MemToAlloc);
 746
 747   DEBUG(dbgs() << "Allocated Type: " << *Ty << " (" << TypeSize << " bytes) x "
 748                << NumElements << " (Total: " << MemToAlloc << ") at "
 749                << uintptr_t(Memory) << '\n');
 750
 751   GenericValue Result = PTOGV(Memory);
 752   assert(Result.PointerVal != 0 && "Null pointer returned by malloc!");
 753   SetValue(&I, Result, SF);
 754
 755   if (I.getOpcode() == Instruction::Alloca)
 756     ECStack.back().Allocas.add(Memory);
 757 }
 758
 759 // getElementOffset - The workhorse for getelementptr.
 760 //
 761 GenericValue Interpreter::executeGEPOperation(Value *Ptr, gep_type_iterator I,
 762                                               gep_type_iterator E,
 763                                               ExecutionContext &SF) {
 764   assert(Ptr->getType()->isPointerTy() &&
 765          "Cannot getElementOffset of a nonpointer type!");
 766
 767   uint64_t Total = 0;
 768
 769   for (; I != E; ++I) {
 770     if (const StructType *STy = dyn_cast<StructType>(*I)) {
 771       const StructLayout *SLO = TD.getStructLayout(STy);
 772
 773       const ConstantInt *CPU = cast<ConstantInt>(I.getOperand());
 774       unsigned Index = unsigned(CPU->getZExtValue());
 775
 776       Total += SLO->getElementOffset(Index);
 777     } else {
 778       const SequentialType *ST = cast<SequentialType>(*I);
 779       // Get the index number for the array... which must be long type...
 780       GenericValue IdxGV = getOperandValue(I.getOperand(), SF);
 781
 782       int64_t Idx;
 783       unsigned BitWidth =
 784         cast<IntegerType>(I.getOperand()->getType())->getBitWidth();
 785       if (BitWidth == 32)
 786         Idx = (int64_t)(int32_t)IdxGV.IntVal.getZExtValue();
 787       else {
 788         assert(BitWidth == 64 && "Invalid index type for getelementptr");
 789         Idx = (int64_t)IdxGV.IntVal.getZExtValue();
 790       }
 791       Total += TD.getTypeAllocSize(ST->getElementType())*Idx;
 792     }
 793   }
 794
 795   GenericValue Result;
 796   Result.PointerVal = ((char*)getOperandValue(Ptr, SF).PointerVal) + Total;
 797   DEBUG(dbgs() << "GEP Index " << Total << " bytes.\n");
 798   return Result;
 799 }
 800
 801 void Interpreter::visitGetElementPtrInst(GetElementPtrInst &I) {
 802   ExecutionContext &SF = ECStack.back();
 803   SetValue(&I, executeGEPOperation(I.getPointerOperand(),
 804                                    gep_type_begin(I), gep_type_end(I), SF), SF);
 805 }
 806
 807 void Interpreter::visitLoadInst(LoadInst &I) {
 808   ExecutionContext &SF = ECStack.back();
 809   GenericValue SRC = getOperandValue(I.getPointerOperand(), SF);
 810   GenericValue *Ptr = (GenericValue*)GVTOP(SRC);
 811   GenericValue Result;
 812   LoadValueFromMemory(Result, Ptr, I.getType());
 813   SetValue(&I, Result, SF);
 814   if (I.isVolatile() && PrintVolatile)
 815     dbgs() << "Volatile load " << I;
 816 }
 817
 818 void Interpreter::visitStoreInst(StoreInst &I) {
 819   ExecutionContext &SF = ECStack.back();
 820   GenericValue Val = getOperandValue(I.getOperand(0), SF);
 821   GenericValue SRC = getOperandValue(I.getPointerOperand(), SF);
 822   StoreValueToMemory(Val, (GenericValue *)GVTOP(SRC),
 823                      I.getOperand(0)->getType());
 824   if (I.isVolatile() && PrintVolatile)
 825     dbgs() << "Volatile store: " << I;
 826 }
 827
 828 //===----------------------------------------------------------------------===//
 829 //                 Miscellaneous Instruction Implementations
 830 //===----------------------------------------------------------------------===//
 831
 832 void Interpreter::visitCallSite(CallSite CS) {
 833   ExecutionContext &SF = ECStack.back();
 834
 835   // Check to see if this is an intrinsic function call...
 836   Function *F = CS.getCalledFunction();
 837   if (F && F->isDeclaration())
 838     switch (F->getIntrinsicID()) {
 839     case Intrinsic::not_intrinsic:
 840       break;
 841     case Intrinsic::vastart: { // va_start
 842       GenericValue ArgIndex;
 843       ArgIndex.UIntPairVal.first = ECStack.size() - 1;
 844       ArgIndex.UIntPairVal.second = 0;
 845       SetValue(CS.getInstruction(), ArgIndex, SF);
 846       return;
 847     }
 848     case Intrinsic::vaend:    // va_end is a noop for the interpreter
 849       return;
 850     case Intrinsic::vacopy:   // va_copy: dest = src
 851       SetValue(CS.getInstruction(), getOperandValue(*CS.arg_begin(), SF), SF);
 852       return;
 853     default:
 854       // If it is an unknown intrinsic function, use the intrinsic lowering
 855       // class to transform it into hopefully tasty LLVM code.
 856       //
 857       BasicBlock::iterator me(CS.getInstruction());
 858       BasicBlock *Parent = CS.getInstruction()->getParent();
 859       bool atBegin(Parent->begin() == me);
 860       if (!atBegin)
 861         --me;
 862       IL->LowerIntrinsicCall(cast<CallInst>(CS.getInstruction()));
 863
 864       // Restore the CurInst pointer to the first instruction newly inserted, if
 865       // any.
 866       if (atBegin) {
 867         SF.CurInst = Parent->begin();
 868       } else {
 869         SF.CurInst = me;
 870         ++SF.CurInst;
 871       }
 872       return;
 873     }
 874
 875
 876   SF.Caller = CS;
 877   std::vector<GenericValue> ArgVals;
 878   const unsigned NumArgs = SF.Caller.arg_size();
 879   ArgVals.reserve(NumArgs);
 880   uint16_t pNum = 1;
 881   for (CallSite::arg_iterator i = SF.Caller.arg_begin(),
 882          e = SF.Caller.arg_end(); i != e; ++i, ++pNum) {
 883     Value *V = *i;
 884     ArgVals.push_back(getOperandValue(V, SF));
 885   }
 886
 887   // To handle indirect calls, we must get the pointer value from the argument
 888   // and treat it as a function pointer.
 889   GenericValue SRC = getOperandValue(SF.Caller.getCalledValue(), SF);
 890   callFunction((Function*)GVTOP(SRC), ArgVals);
 891 }
 892
 893 void Interpreter::visitShl(BinaryOperator &I) {
 894   ExecutionContext &SF = ECStack.back();
 895   GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
 896   GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
 897   GenericValue Dest;
 898   if (Src2.IntVal.getZExtValue() < Src1.IntVal.getBitWidth())
 899     Dest.IntVal = Src1.IntVal.shl(Src2.IntVal.getZExtValue());
 900   else
 901     Dest.IntVal = Src1.IntVal;
 902
 903   SetValue(&I, Dest, SF);
 904 }
 905
 906 void Interpreter::visitLShr(BinaryOperator &I) {
 907   ExecutionContext &SF = ECStack.back();
 908   GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
 909   GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
 910   GenericValue Dest;
 911   if (Src2.IntVal.getZExtValue() < Src1.IntVal.getBitWidth())
 912     Dest.IntVal = Src1.IntVal.lshr(Src2.IntVal.getZExtValue());
 913   else
 914     Dest.IntVal = Src1.IntVal;
 915
 916   SetValue(&I, Dest, SF);
 917 }
 918
 919 void Interpreter::visitAShr(BinaryOperator &I) {
 920   ExecutionContext &SF = ECStack.back();
 921   GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
 922   GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
 923   GenericValue Dest;
 924   if (Src2.IntVal.getZExtValue() < Src1.IntVal.getBitWidth())
 925     Dest.IntVal = Src1.IntVal.ashr(Src2.IntVal.getZExtValue());
 926   else
 927     Dest.IntVal = Src1.IntVal;
 928
 929   SetValue(&I, Dest, SF);
 930 }
 931
 932 GenericValue Interpreter::executeTruncInst(Value *SrcVal, const Type *DstTy,
 933                                            ExecutionContext &SF) {
 934   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
 935   const IntegerType *DITy = cast<IntegerType>(DstTy);
 936   unsigned DBitWidth = DITy->getBitWidth();
 937   Dest.IntVal = Src.IntVal.trunc(DBitWidth);
 938   return Dest;
 939 }
 940
 941 GenericValue Interpreter::executeSExtInst(Value *SrcVal, const Type *DstTy,
 942                                           ExecutionContext &SF) {
 943   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
 944   const IntegerType *DITy = cast<IntegerType>(DstTy);
 945   unsigned DBitWidth = DITy->getBitWidth();
 946   Dest.IntVal = Src.IntVal.sext(DBitWidth);
 947   return Dest;
 948 }
 949
 950 GenericValue Interpreter::executeZExtInst(Value *SrcVal, const Type *DstTy,
 951                                           ExecutionContext &SF) {
 952   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
 953   const IntegerType *DITy = cast<IntegerType>(DstTy);
 954   unsigned DBitWidth = DITy->getBitWidth();
 955   Dest.IntVal = Src.IntVal.zext(DBitWidth);
 956   return Dest;
 957 }
 958
 959 GenericValue Interpreter::executeFPTruncInst(Value *SrcVal, const Type *DstTy,
 960                                              ExecutionContext &SF) {
 961   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
 962   assert(SrcVal->getType()->isDoubleTy() && DstTy->isFloatTy() &&
 963          "Invalid FPTrunc instruction");
 964   Dest.FloatVal = (float) Src.DoubleVal;
 965   return Dest;
 966 }
 967
 968 GenericValue Interpreter::executeFPExtInst(Value *SrcVal, const Type *DstTy,
 969                                            ExecutionContext &SF) {
 970   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
 971   assert(SrcVal->getType()->isFloatTy() && DstTy->isDoubleTy() &&
 972          "Invalid FPTrunc instruction");
 973   Dest.DoubleVal = (double) Src.FloatVal;
 974   return Dest;
 975 }
 976
 977 GenericValue Interpreter::executeFPToUIInst(Value *SrcVal, const Type *DstTy,
 978                                             ExecutionContext &SF) {
 979   const Type *SrcTy = SrcVal->getType();
 980   uint32_t DBitWidth = cast<IntegerType>(DstTy)->getBitWidth();
 981   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
 982   assert(SrcTy->isFloatingPointTy() && "Invalid FPToUI instruction");
 983
 984   if (SrcTy->getTypeID() == Type::FloatTyID)
 985     Dest.IntVal = APIntOps::RoundFloatToAPInt(Src.FloatVal, DBitWidth);
 986   else
 987     Dest.IntVal = APIntOps::RoundDoubleToAPInt(Src.DoubleVal, DBitWidth);
 988   return Dest;
 989 }
 990
 991 GenericValue Interpreter::executeFPToSIInst(Value *SrcVal, const Type *DstTy,
 992                                             ExecutionContext &SF) {
 993   const Type *SrcTy = SrcVal->getType();
 994   uint32_t DBitWidth = cast<IntegerType>(DstTy)->getBitWidth();
 995   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
 996   assert(SrcTy->isFloatingPointTy() && "Invalid FPToSI instruction");
 997
 998   if (SrcTy->getTypeID() == Type::FloatTyID)
 999     Dest.IntVal = APIntOps::RoundFloatToAPInt(Src.FloatVal, DBitWidth);
1000   else
1001     Dest.IntVal = APIntOps::RoundDoubleToAPInt(Src.DoubleVal, DBitWidth);
1002   return Dest;
1003 }
1004
1005 GenericValue Interpreter::executeUIToFPInst(Value *SrcVal, const Type *DstTy,
1006                                             ExecutionContext &SF) {
1007   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1008   assert(DstTy->isFloatingPointTy() && "Invalid UIToFP instruction");
1009
1010   if (DstTy->getTypeID() == Type::FloatTyID)
1011     Dest.FloatVal = APIntOps::RoundAPIntToFloat(Src.IntVal);
1012   else
1013     Dest.DoubleVal = APIntOps::RoundAPIntToDouble(Src.IntVal);
1014   return Dest;
1015 }
1016
1017 GenericValue Interpreter::executeSIToFPInst(Value *SrcVal, const Type *DstTy,
1018                                             ExecutionContext &SF) {
1019   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1020   assert(DstTy->isFloatingPointTy() && "Invalid SIToFP instruction");
1021
1022   if (DstTy->getTypeID() == Type::FloatTyID)
1023     Dest.FloatVal = APIntOps::RoundSignedAPIntToFloat(Src.IntVal);
1024   else
1025     Dest.DoubleVal = APIntOps::RoundSignedAPIntToDouble(Src.IntVal);
1026   return Dest;
1027
1028 }
1029
1030 GenericValue Interpreter::executePtrToIntInst(Value *SrcVal, const Type *DstTy,
1031                                               ExecutionContext &SF) {
1032   uint32_t DBitWidth = cast<IntegerType>(DstTy)->getBitWidth();
1033   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1034   assert(SrcVal->getType()->isPointerTy() && "Invalid PtrToInt instruction");
1035
1036   Dest.IntVal = APInt(DBitWidth, (intptr_t) Src.PointerVal);
1037   return Dest;
1038 }
1039
1040 GenericValue Interpreter::executeIntToPtrInst(Value *SrcVal, const Type *DstTy,
1041                                               ExecutionContext &SF) {
1042   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1043   assert(DstTy->isPointerTy() && "Invalid PtrToInt instruction");
1044
1045   uint32_t PtrSize = TD.getPointerSizeInBits();
1046   if (PtrSize != Src.IntVal.getBitWidth())
1047     Src.IntVal = Src.IntVal.zextOrTrunc(PtrSize);
1048
1049   Dest.PointerVal = PointerTy(intptr_t(Src.IntVal.getZExtValue()));
1050   return Dest;
1051 }
1052
1053 GenericValue Interpreter::executeBitCastInst(Value *SrcVal, const Type *DstTy,
1054                                              ExecutionContext &SF) {
1055
1056   const Type *SrcTy = SrcVal->getType();
1057   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1058   if (DstTy->isPointerTy()) {
1059     assert(SrcTy->isPointerTy() && "Invalid BitCast");
1060     Dest.PointerVal = Src.PointerVal;
1061   } else if (DstTy->isIntegerTy()) {
1062     if (SrcTy->isFloatTy()) {
1063       Dest.IntVal = APInt::floatToBits(Src.FloatVal);
1064     } else if (SrcTy->isDoubleTy()) {
1065       Dest.IntVal = APInt::doubleToBits(Src.DoubleVal);
1066     } else if (SrcTy->isIntegerTy()) {
1067       Dest.IntVal = Src.IntVal;
1068     } else
1069       llvm_unreachable("Invalid BitCast");
1070   } else if (DstTy->isFloatTy()) {
1071     if (SrcTy->isIntegerTy())
1072       Dest.FloatVal = Src.IntVal.bitsToFloat();
1073     else
1074       Dest.FloatVal = Src.FloatVal;
1075   } else if (DstTy->isDoubleTy()) {
1076     if (SrcTy->isIntegerTy())
1077       Dest.DoubleVal = Src.IntVal.bitsToDouble();
1078     else
1079       Dest.DoubleVal = Src.DoubleVal;
1080   } else
1081     llvm_unreachable("Invalid Bitcast");
1082
1083   return Dest;
1084 }
1085
1086 void Interpreter::visitTruncInst(TruncInst &I) {
1087   ExecutionContext &SF = ECStack.back();
1088   SetValue(&I, executeTruncInst(I.getOperand(0), I.getType(), SF), SF);
1089 }
1090
1091 void Interpreter::visitSExtInst(SExtInst &I) {
1092   ExecutionContext &SF = ECStack.back();
1093   SetValue(&I, executeSExtInst(I.getOperand(0), I.getType(), SF), SF);
1094 }
1095
1096 void Interpreter::visitZExtInst(ZExtInst &I) {
1097   ExecutionContext &SF = ECStack.back();
1098   SetValue(&I, executeZExtInst(I.getOperand(0), I.getType(), SF), SF);
1099 }
1100
1101 void Interpreter::visitFPTruncInst(FPTruncInst &I) {
1102   ExecutionContext &SF = ECStack.back();
1103   SetValue(&I, executeFPTruncInst(I.getOperand(0), I.getType(), SF), SF);
1104 }
1105
1106 void Interpreter::visitFPExtInst(FPExtInst &I) {
1107   ExecutionContext &SF = ECStack.back();
1108   SetValue(&I, executeFPExtInst(I.getOperand(0), I.getType(), SF), SF);
1109 }
1110
1111 void Interpreter::visitUIToFPInst(UIToFPInst &I) {
1112   ExecutionContext &SF = ECStack.back();
1113   SetValue(&I, executeUIToFPInst(I.getOperand(0), I.getType(), SF), SF);
1114 }
1115
1116 void Interpreter::visitSIToFPInst(SIToFPInst &I) {
1117   ExecutionContext &SF = ECStack.back();
1118   SetValue(&I, executeSIToFPInst(I.getOperand(0), I.getType(), SF), SF);
1119 }
1120
1121 void Interpreter::visitFPToUIInst(FPToUIInst &I) {
1122   ExecutionContext &SF = ECStack.back();
1123   SetValue(&I, executeFPToUIInst(I.getOperand(0), I.getType(), SF), SF);
1124 }
1125
1126 void Interpreter::visitFPToSIInst(FPToSIInst &I) {
1127   ExecutionContext &SF = ECStack.back();
1128   SetValue(&I, executeFPToSIInst(I.getOperand(0), I.getType(), SF), SF);
1129 }
1130
1131 void Interpreter::visitPtrToIntInst(PtrToIntInst &I) {
1132   ExecutionContext &SF = ECStack.back();
1133   SetValue(&I, executePtrToIntInst(I.getOperand(0), I.getType(), SF), SF);
1134 }
1135
1136 void Interpreter::visitIntToPtrInst(IntToPtrInst &I) {
1137   ExecutionContext &SF = ECStack.back();
1138   SetValue(&I, executeIntToPtrInst(I.getOperand(0), I.getType(), SF), SF);
1139 }
1140
1141 void Interpreter::visitBitCastInst(BitCastInst &I) {
1142   ExecutionContext &SF = ECStack.back();
1143   SetValue(&I, executeBitCastInst(I.getOperand(0), I.getType(), SF), SF);
1144 }
1145
1146 #define IMPLEMENT_VAARG(TY) \
1147    case Type::TY##TyID: Dest.TY##Val = Src.TY##Val; break
1148
1149 void Interpreter::visitVAArgInst(VAArgInst &I) {
1150   ExecutionContext &SF = ECStack.back();
1151
1152   // Get the incoming valist parameter.  LLI treats the valist as a
1153   // (ec-stack-depth var-arg-index) pair.
1154   GenericValue VAList = getOperandValue(I.getOperand(0), SF);
1155   GenericValue Dest;
1156   GenericValue Src = ECStack[VAList.UIntPairVal.first]
1157                       .VarArgs[VAList.UIntPairVal.second];
1158   const Type *Ty = I.getType();
1159   switch (Ty->getTypeID()) {
1160     case Type::IntegerTyID: Dest.IntVal = Src.IntVal;
1161     IMPLEMENT_VAARG(Pointer);
1162     IMPLEMENT_VAARG(Float);
1163     IMPLEMENT_VAARG(Double);
1164   default:
1165     dbgs() << "Unhandled dest type for vaarg instruction: " << *Ty << "\n";
1166     llvm_unreachable(0);
1167   }
1168
1169   // Set the Value of this Instruction.
1170   SetValue(&I, Dest, SF);
1171
1172   // Move the pointer to the next vararg.
1173   ++VAList.UIntPairVal.second;
1174 }
1175
1176 GenericValue Interpreter::getConstantExprValue (ConstantExpr *CE,
1177                                                 ExecutionContext &SF) {
1178   switch (CE->getOpcode()) {
1179   case Instruction::Trunc:
1180       return executeTruncInst(CE->getOperand(0), CE->getType(), SF);
1181   case Instruction::ZExt:
1182       return executeZExtInst(CE->getOperand(0), CE->getType(), SF);
1183   case Instruction::SExt:
1184       return executeSExtInst(CE->getOperand(0), CE->getType(), SF);
1185   case Instruction::FPTrunc:
1186       return executeFPTruncInst(CE->getOperand(0), CE->getType(), SF);
1187   case Instruction::FPExt:
1188       return executeFPExtInst(CE->getOperand(0), CE->getType(), SF);
1189   case Instruction::UIToFP:
1190       return executeUIToFPInst(CE->getOperand(0), CE->getType(), SF);
1191   case Instruction::SIToFP:
1192       return executeSIToFPInst(CE->getOperand(0), CE->getType(), SF);
1193   case Instruction::FPToUI:
1194       return executeFPToUIInst(CE->getOperand(0), CE->getType(), SF);
1195   case Instruction::FPToSI:
1196       return executeFPToSIInst(CE->getOperand(0), CE->getType(), SF);
1197   case Instruction::PtrToInt:
1198       return executePtrToIntInst(CE->getOperand(0), CE->getType(), SF);
1199   case Instruction::IntToPtr:
1200       return executeIntToPtrInst(CE->getOperand(0), CE->getType(), SF);
1201   case Instruction::BitCast:
1202       return executeBitCastInst(CE->getOperand(0), CE->getType(), SF);
1203   case Instruction::GetElementPtr:
1204     return executeGEPOperation(CE->getOperand(0), gep_type_begin(CE),
1205                                gep_type_end(CE), SF);
1206   case Instruction::FCmp:
1207   case Instruction::ICmp:
1208     return executeCmpInst(CE->getPredicate(),
1209                           getOperandValue(CE->getOperand(0), SF),
1210                           getOperandValue(CE->getOperand(1), SF),
1211                           CE->getOperand(0)->getType());
1212   case Instruction::Select:
1213     return executeSelectInst(getOperandValue(CE->getOperand(0), SF),
1214                              getOperandValue(CE->getOperand(1), SF),
1215                              getOperandValue(CE->getOperand(2), SF));
1216   default :
1217     break;
1218   }
1219
1220   // The cases below here require a GenericValue parameter for the result
1221   // so we initialize one, compute it and then return it.
1222   GenericValue Op0 = getOperandValue(CE->getOperand(0), SF);
1223   GenericValue Op1 = getOperandValue(CE->getOperand(1), SF);
1224   GenericValue Dest;
1225   const Type * Ty = CE->getOperand(0)->getType();
1226   switch (CE->getOpcode()) {
1227   case Instruction::Add:  Dest.IntVal = Op0.IntVal + Op1.IntVal; break;
1228   case Instruction::Sub:  Dest.IntVal = Op0.IntVal - Op1.IntVal; break;
1229   case Instruction::Mul:  Dest.IntVal = Op0.IntVal * Op1.IntVal; break;
1230   case Instruction::FAdd: executeFAddInst(Dest, Op0, Op1, Ty); break;
1231   case Instruction::FSub: executeFSubInst(Dest, Op0, Op1, Ty); break;
1232   case Instruction::FMul: executeFMulInst(Dest, Op0, Op1, Ty); break;
1233   case Instruction::FDiv: executeFDivInst(Dest, Op0, Op1, Ty); break;
1234   case Instruction::FRem: executeFRemInst(Dest, Op0, Op1, Ty); break;
1235   case Instruction::SDiv: Dest.IntVal = Op0.IntVal.sdiv(Op1.IntVal); break;
1236   case Instruction::UDiv: Dest.IntVal = Op0.IntVal.udiv(Op1.IntVal); break;
1237   case Instruction::URem: Dest.IntVal = Op0.IntVal.urem(Op1.IntVal); break;
1238   case Instruction::SRem: Dest.IntVal = Op0.IntVal.srem(Op1.IntVal); break;
1239   case Instruction::And:  Dest.IntVal = Op0.IntVal & Op1.IntVal; break;
1240   case Instruction::Or:   Dest.IntVal = Op0.IntVal | Op1.IntVal; break;
1241   case Instruction::Xor:  Dest.IntVal = Op0.IntVal ^ Op1.IntVal; break;
1242   case Instruction::Shl:
1243     Dest.IntVal = Op0.IntVal.shl(Op1.IntVal.getZExtValue());
1244     break;
1245   case Instruction::LShr:
1246     Dest.IntVal = Op0.IntVal.lshr(Op1.IntVal.getZExtValue());
1247     break;
1248   case Instruction::AShr:
1249     Dest.IntVal = Op0.IntVal.ashr(Op1.IntVal.getZExtValue());
1250     break;
1251   default:
1252     dbgs() << "Unhandled ConstantExpr: " << *CE << "\n";
1253     llvm_unreachable(0);
1254     return GenericValue();
1255   }
1256   return Dest;
1257 }
1258
1259 GenericValue Interpreter::getOperandValue(Value *V, ExecutionContext &SF) {
1260   if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
1261     return getConstantExprValue(CE, SF);
1262   } else if (Constant *CPV = dyn_cast<Constant>(V)) {
1263     return getConstantValue(CPV);
1264   } else if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
1265     return PTOGV(getPointerToGlobal(GV));
1266   } else {
1267     return SF.Values[V];
1268   }
1269 }
1270
1271 //===----------------------------------------------------------------------===//
1272 //                        Dispatch and Execution Code
1273 //===----------------------------------------------------------------------===//
1274
1275 //===----------------------------------------------------------------------===//
1276 // callFunction - Execute the specified function...
1277 //
1278 void Interpreter::callFunction(Function *F,
1279                                const std::vector<GenericValue> &ArgVals) {
1280   assert((ECStack.empty() || ECStack.back().Caller.getInstruction() == 0 ||
1281           ECStack.back().Caller.arg_size() == ArgVals.size()) &&
1282          "Incorrect number of arguments passed into function call!");
1283   // Make a new stack frame... and fill it in.
1284   ECStack.push_back(ExecutionContext());
1285   ExecutionContext &StackFrame = ECStack.back();
1286   StackFrame.CurFunction = F;
1287
1288   // Special handling for external functions.
1289   if (F->isDeclaration()) {
1290     GenericValue Result = callExternalFunction (F, ArgVals);
1291     // Simulate a 'ret' instruction of the appropriate type.
1292     popStackAndReturnValueToCaller (F->getReturnType (), Result);
1293     return;
1294   }
1295
1296   // Get pointers to first LLVM BB & Instruction in function.
1297   StackFrame.CurBB     = F->begin();
1298   StackFrame.CurInst   = StackFrame.CurBB->begin();
1299
1300   // Run through the function arguments and initialize their values...
1301   assert((ArgVals.size() == F->arg_size() ||
1302          (ArgVals.size() > F->arg_size() && F->getFunctionType()->isVarArg()))&&
1303          "Invalid number of values passed to function invocation!");
1304
1305   // Handle non-varargs arguments...
1306   unsigned i = 0;
1307   for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end();
1308        AI != E; ++AI, ++i)
1309     SetValue(AI, ArgVals[i], StackFrame);
1310
1311   // Handle varargs arguments...
1312   StackFrame.VarArgs.assign(ArgVals.begin()+i, ArgVals.end());
1313 }
1314
1315
1316 void Interpreter::run() {
1317   while (!ECStack.empty()) {
1318     // Interpret a single instruction & increment the "PC".
1319     ExecutionContext &SF = ECStack.back();  // Current stack frame
1320     Instruction &I = *SF.CurInst++;         // Increment before execute
1321
1322     // Track the number of dynamic instructions executed.
1323     ++NumDynamicInsts;
1324
1325     DEBUG(dbgs() << "About to interpret: " << I);
1326     visit(I);   // Dispatch to one of the visit* methods...
1327 #if 0
1328     // This is not safe, as visiting the instruction could lower it and free I.
1329 DEBUG(
1330     if (!isa<CallInst>(I) && !isa<InvokeInst>(I) &&
1331         I.getType() != Type::VoidTy) {
1332       dbgs() << "  --> ";
1333       const GenericValue &Val = SF.Values[&I];
1334       switch (I.getType()->getTypeID()) {
1335       default: llvm_unreachable("Invalid GenericValue Type");
1336       case Type::VoidTyID:    dbgs() << "void"; break;
1337       case Type::FloatTyID:   dbgs() << "float " << Val.FloatVal; break;
1338       case Type::DoubleTyID:  dbgs() << "double " << Val.DoubleVal; break;
1339       case Type::PointerTyID: dbgs() << "void* " << intptr_t(Val.PointerVal);
1340         break;
1341       case Type::IntegerTyID:
1342         dbgs() << "i" << Val.IntVal.getBitWidth() << " "
1343                << Val.IntVal.toStringUnsigned(10)
1344                << " (0x" << Val.IntVal.toStringUnsigned(16) << ")\n";
1345         break;
1346       }
1347     });
1348 #endif
1349   }
1350 }