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     errs() << "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     errs() << "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     errs() << "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     errs() << "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     errs() << "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     errs() << "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     errs() << "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     errs() << "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     errs() << "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     errs() << "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     errs() << "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     errs() << "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     errs() << "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     errs() << "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     errs() << "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     errs() << "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     errs() << "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     errs() << "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     errs() << "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     errs() << "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     errs() << "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     errs() << "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 == Type::getFloatTy(Ty->getContext())) {                        \
 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 == Type::getFloatTy(Ty->getContext()))
 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 == Type::getFloatTy(Ty->getContext()))
 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     errs() << "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     errs() << "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     errs() << "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->isInteger()) {          // 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() != Type::getVoidTy(RetTy->getContext()))
 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       llvm_report_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   llvm_report_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 // SwitchToNewBasicBlock - This method is used to jump to a new basic block.
 682 // This function handles the actual updating of block and instruction iterators
 683 // as well as execution of all of the PHI nodes in the destination block.
 684 //
 685 // This method does this because all of the PHI nodes must be executed
 686 // atomically, reading their inputs before any of the results are updated.  Not
 687 // doing this can cause problems if the PHI nodes depend on other PHI nodes for
 688 // their inputs.  If the input PHI node is updated before it is read, incorrect
 689 // results can happen.  Thus we use a two phase approach.
 690 //
 691 void Interpreter::SwitchToNewBasicBlock(BasicBlock *Dest, ExecutionContext &SF){
 692   BasicBlock *PrevBB = SF.CurBB;      // Remember where we came from...
 693   SF.CurBB   = Dest;                  // Update CurBB to branch destination
 694   SF.CurInst = SF.CurBB->begin();     // Update new instruction ptr...
 695
 696   if (!isa<PHINode>(SF.CurInst)) return;  // Nothing fancy to do
 697
 698   // Loop over all of the PHI nodes in the current block, reading their inputs.
 699   std::vector<GenericValue> ResultValues;
 700
 701   for (; PHINode *PN = dyn_cast<PHINode>(SF.CurInst); ++SF.CurInst) {
 702     // Search for the value corresponding to this previous bb...
 703     int i = PN->getBasicBlockIndex(PrevBB);
 704     assert(i != -1 && "PHINode doesn't contain entry for predecessor??");
 705     Value *IncomingValue = PN->getIncomingValue(i);
 706
 707     // Save the incoming value for this PHI node...
 708     ResultValues.push_back(getOperandValue(IncomingValue, SF));
 709   }
 710
 711   // Now loop over all of the PHI nodes setting their values...
 712   SF.CurInst = SF.CurBB->begin();
 713   for (unsigned i = 0; isa<PHINode>(SF.CurInst); ++SF.CurInst, ++i) {
 714     PHINode *PN = cast<PHINode>(SF.CurInst);
 715     SetValue(PN, ResultValues[i], SF);
 716   }
 717 }
 718
 719 //===----------------------------------------------------------------------===//
 720 //                     Memory Instruction Implementations
 721 //===----------------------------------------------------------------------===//
 722
 723 void Interpreter::visitAllocationInst(AllocationInst &I) {
 724   ExecutionContext &SF = ECStack.back();
 725
 726   const Type *Ty = I.getType()->getElementType();  // Type to be allocated
 727
 728   // Get the number of elements being allocated by the array...
 729   unsigned NumElements =
 730     getOperandValue(I.getOperand(0), SF).IntVal.getZExtValue();
 731
 732   unsigned TypeSize = (size_t)TD.getTypeAllocSize(Ty);
 733
 734   // Avoid malloc-ing zero bytes, use max()...
 735   unsigned MemToAlloc = std::max(1U, NumElements * TypeSize);
 736
 737   // Allocate enough memory to hold the type...
 738   void *Memory = malloc(MemToAlloc);
 739
 740   DEBUG(errs() << "Allocated Type: " << *Ty << " (" << TypeSize << " bytes) x "
 741                << NumElements << " (Total: " << MemToAlloc << ") at "
 742                << uintptr_t(Memory) << '\n');
 743
 744   GenericValue Result = PTOGV(Memory);
 745   assert(Result.PointerVal != 0 && "Null pointer returned by malloc!");
 746   SetValue(&I, Result, SF);
 747
 748   if (I.getOpcode() == Instruction::Alloca)
 749     ECStack.back().Allocas.add(Memory);
 750 }
 751
 752 void Interpreter::visitFreeInst(FreeInst &I) {
 753   ExecutionContext &SF = ECStack.back();
 754   assert(isa<PointerType>(I.getOperand(0)->getType()) && "Freeing nonptr?");
 755   GenericValue Value = getOperandValue(I.getOperand(0), SF);
 756   // TODO: Check to make sure memory is allocated
 757   free(GVTOP(Value));   // Free memory
 758 }
 759
 760 // getElementOffset - The workhorse for getelementptr.
 761 //
 762 GenericValue Interpreter::executeGEPOperation(Value *Ptr, gep_type_iterator I,
 763                                               gep_type_iterator E,
 764                                               ExecutionContext &SF) {
 765   assert(isa<PointerType>(Ptr->getType()) &&
 766          "Cannot getElementOffset of a nonpointer type!");
 767
 768   uint64_t Total = 0;
 769
 770   for (; I != E; ++I) {
 771     if (const StructType *STy = dyn_cast<StructType>(*I)) {
 772       const StructLayout *SLO = TD.getStructLayout(STy);
 773
 774       const ConstantInt *CPU = cast<ConstantInt>(I.getOperand());
 775       unsigned Index = unsigned(CPU->getZExtValue());
 776
 777       Total += SLO->getElementOffset(Index);
 778     } else {
 779       const SequentialType *ST = cast<SequentialType>(*I);
 780       // Get the index number for the array... which must be long type...
 781       GenericValue IdxGV = getOperandValue(I.getOperand(), SF);
 782
 783       int64_t Idx;
 784       unsigned BitWidth =
 785         cast<IntegerType>(I.getOperand()->getType())->getBitWidth();
 786       if (BitWidth == 32)
 787         Idx = (int64_t)(int32_t)IdxGV.IntVal.getZExtValue();
 788       else {
 789         assert(BitWidth == 64 && "Invalid index type for getelementptr");
 790         Idx = (int64_t)IdxGV.IntVal.getZExtValue();
 791       }
 792       Total += TD.getTypeAllocSize(ST->getElementType())*Idx;
 793     }
 794   }
 795
 796   GenericValue Result;
 797   Result.PointerVal = ((char*)getOperandValue(Ptr, SF).PointerVal) + Total;
 798   DEBUG(errs() << "GEP Index " << Total << " bytes.\n");
 799   return Result;
 800 }
 801
 802 void Interpreter::visitGetElementPtrInst(GetElementPtrInst &I) {
 803   ExecutionContext &SF = ECStack.back();
 804   SetValue(&I, executeGEPOperation(I.getPointerOperand(),
 805                                    gep_type_begin(I), gep_type_end(I), SF), SF);
 806 }
 807
 808 void Interpreter::visitLoadInst(LoadInst &I) {
 809   ExecutionContext &SF = ECStack.back();
 810   GenericValue SRC = getOperandValue(I.getPointerOperand(), SF);
 811   GenericValue *Ptr = (GenericValue*)GVTOP(SRC);
 812   GenericValue Result;
 813   LoadValueFromMemory(Result, Ptr, I.getType());
 814   SetValue(&I, Result, SF);
 815   if (I.isVolatile() && PrintVolatile)
 816     errs() << "Volatile load " << I;
 817 }
 818
 819 void Interpreter::visitStoreInst(StoreInst &I) {
 820   ExecutionContext &SF = ECStack.back();
 821   GenericValue Val = getOperandValue(I.getOperand(0), SF);
 822   GenericValue SRC = getOperandValue(I.getPointerOperand(), SF);
 823   StoreValueToMemory(Val, (GenericValue *)GVTOP(SRC),
 824                      I.getOperand(0)->getType());
 825   if (I.isVolatile() && PrintVolatile)
 826     errs() << "Volatile store: " << I;
 827 }
 828
 829 //===----------------------------------------------------------------------===//
 830 //                 Miscellaneous Instruction Implementations
 831 //===----------------------------------------------------------------------===//
 832
 833 void Interpreter::visitCallSite(CallSite CS) {
 834   ExecutionContext &SF = ECStack.back();
 835
 836   // Check to see if this is an intrinsic function call...
 837   Function *F = CS.getCalledFunction();
 838   if (F && F->isDeclaration ())
 839     switch (F->getIntrinsicID()) {
 840     case Intrinsic::not_intrinsic:
 841       break;
 842     case Intrinsic::vastart: { // va_start
 843       GenericValue ArgIndex;
 844       ArgIndex.UIntPairVal.first = ECStack.size() - 1;
 845       ArgIndex.UIntPairVal.second = 0;
 846       SetValue(CS.getInstruction(), ArgIndex, SF);
 847       return;
 848     }
 849     case Intrinsic::vaend:    // va_end is a noop for the interpreter
 850       return;
 851     case Intrinsic::vacopy:   // va_copy: dest = src
 852       SetValue(CS.getInstruction(), getOperandValue(*CS.arg_begin(), SF), SF);
 853       return;
 854     default:
 855       // If it is an unknown intrinsic function, use the intrinsic lowering
 856       // class to transform it into hopefully tasty LLVM code.
 857       //
 858       BasicBlock::iterator me(CS.getInstruction());
 859       BasicBlock *Parent = CS.getInstruction()->getParent();
 860       bool atBegin(Parent->begin() == me);
 861       if (!atBegin)
 862         --me;
 863       IL->LowerIntrinsicCall(cast<CallInst>(CS.getInstruction()));
 864
 865       // Restore the CurInst pointer to the first instruction newly inserted, if
 866       // any.
 867       if (atBegin) {
 868         SF.CurInst = Parent->begin();
 869       } else {
 870         SF.CurInst = me;
 871         ++SF.CurInst;
 872       }
 873       return;
 874     }
 875
 876
 877   SF.Caller = CS;
 878   std::vector<GenericValue> ArgVals;
 879   const unsigned NumArgs = SF.Caller.arg_size();
 880   ArgVals.reserve(NumArgs);
 881   uint16_t pNum = 1;
 882   for (CallSite::arg_iterator i = SF.Caller.arg_begin(),
 883          e = SF.Caller.arg_end(); i != e; ++i, ++pNum) {
 884     Value *V = *i;
 885     ArgVals.push_back(getOperandValue(V, SF));
 886     // Promote all integral types whose size is < sizeof(i32) into i32.
 887     // We do this by zero or sign extending the value as appropriate
 888     // according to the parameter attributes
 889     const Type *Ty = V->getType();
 890     if (Ty->isInteger() && (ArgVals.back().IntVal.getBitWidth() < 32)) {
 891       if (CS.paramHasAttr(pNum, Attribute::ZExt))
 892         ArgVals.back().IntVal = ArgVals.back().IntVal.zext(32);
 893       else if (CS.paramHasAttr(pNum, Attribute::SExt))
 894         ArgVals.back().IntVal = ArgVals.back().IntVal.sext(32);
 895     }
 896   }
 897
 898   // To handle indirect calls, we must get the pointer value from the argument
 899   // and treat it as a function pointer.
 900   GenericValue SRC = getOperandValue(SF.Caller.getCalledValue(), SF);
 901   callFunction((Function*)GVTOP(SRC), ArgVals);
 902 }
 903
 904 void Interpreter::visitShl(BinaryOperator &I) {
 905   ExecutionContext &SF = ECStack.back();
 906   GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
 907   GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
 908   GenericValue Dest;
 909   if (Src2.IntVal.getZExtValue() < Src1.IntVal.getBitWidth())
 910     Dest.IntVal = Src1.IntVal.shl(Src2.IntVal.getZExtValue());
 911   else
 912     Dest.IntVal = Src1.IntVal;
 913
 914   SetValue(&I, Dest, SF);
 915 }
 916
 917 void Interpreter::visitLShr(BinaryOperator &I) {
 918   ExecutionContext &SF = ECStack.back();
 919   GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
 920   GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
 921   GenericValue Dest;
 922   if (Src2.IntVal.getZExtValue() < Src1.IntVal.getBitWidth())
 923     Dest.IntVal = Src1.IntVal.lshr(Src2.IntVal.getZExtValue());
 924   else
 925     Dest.IntVal = Src1.IntVal;
 926
 927   SetValue(&I, Dest, SF);
 928 }
 929
 930 void Interpreter::visitAShr(BinaryOperator &I) {
 931   ExecutionContext &SF = ECStack.back();
 932   GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
 933   GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
 934   GenericValue Dest;
 935   if (Src2.IntVal.getZExtValue() < Src1.IntVal.getBitWidth())
 936     Dest.IntVal = Src1.IntVal.ashr(Src2.IntVal.getZExtValue());
 937   else
 938     Dest.IntVal = Src1.IntVal;
 939
 940   SetValue(&I, Dest, SF);
 941 }
 942
 943 GenericValue Interpreter::executeTruncInst(Value *SrcVal, const Type *DstTy,
 944                                            ExecutionContext &SF) {
 945   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
 946   const IntegerType *DITy = cast<IntegerType>(DstTy);
 947   unsigned DBitWidth = DITy->getBitWidth();
 948   Dest.IntVal = Src.IntVal.trunc(DBitWidth);
 949   return Dest;
 950 }
 951
 952 GenericValue Interpreter::executeSExtInst(Value *SrcVal, const Type *DstTy,
 953                                           ExecutionContext &SF) {
 954   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
 955   const IntegerType *DITy = cast<IntegerType>(DstTy);
 956   unsigned DBitWidth = DITy->getBitWidth();
 957   Dest.IntVal = Src.IntVal.sext(DBitWidth);
 958   return Dest;
 959 }
 960
 961 GenericValue Interpreter::executeZExtInst(Value *SrcVal, const Type *DstTy,
 962                                           ExecutionContext &SF) {
 963   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
 964   const IntegerType *DITy = cast<IntegerType>(DstTy);
 965   unsigned DBitWidth = DITy->getBitWidth();
 966   Dest.IntVal = Src.IntVal.zext(DBitWidth);
 967   return Dest;
 968 }
 969
 970 GenericValue Interpreter::executeFPTruncInst(Value *SrcVal, const Type *DstTy,
 971                                              ExecutionContext &SF) {
 972   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
 973   assert(SrcVal->getType() == Type::getDoubleTy(SrcVal->getContext()) &&
 974          DstTy == Type::getFloatTy(SrcVal->getContext()) &&
 975          "Invalid FPTrunc instruction");
 976   Dest.FloatVal = (float) Src.DoubleVal;
 977   return Dest;
 978 }
 979
 980 GenericValue Interpreter::executeFPExtInst(Value *SrcVal, const Type *DstTy,
 981                                            ExecutionContext &SF) {
 982   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
 983   assert(SrcVal->getType() == Type::getFloatTy(SrcVal->getContext()) &&
 984          DstTy == Type::getDoubleTy(SrcVal->getContext()) &&
 985          "Invalid FPTrunc instruction");
 986   Dest.DoubleVal = (double) Src.FloatVal;
 987   return Dest;
 988 }
 989
 990 GenericValue Interpreter::executeFPToUIInst(Value *SrcVal, const Type *DstTy,
 991                                             ExecutionContext &SF) {
 992   const Type *SrcTy = SrcVal->getType();
 993   uint32_t DBitWidth = cast<IntegerType>(DstTy)->getBitWidth();
 994   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
 995   assert(SrcTy->isFloatingPoint() && "Invalid FPToUI instruction");
 996
 997   if (SrcTy->getTypeID() == Type::FloatTyID)
 998     Dest.IntVal = APIntOps::RoundFloatToAPInt(Src.FloatVal, DBitWidth);
 999   else
1000     Dest.IntVal = APIntOps::RoundDoubleToAPInt(Src.DoubleVal, DBitWidth);
1001   return Dest;
1002 }
1003
1004 GenericValue Interpreter::executeFPToSIInst(Value *SrcVal, const Type *DstTy,
1005                                             ExecutionContext &SF) {
1006   const Type *SrcTy = SrcVal->getType();
1007   uint32_t DBitWidth = cast<IntegerType>(DstTy)->getBitWidth();
1008   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1009   assert(SrcTy->isFloatingPoint() && "Invalid FPToSI instruction");
1010
1011   if (SrcTy->getTypeID() == Type::FloatTyID)
1012     Dest.IntVal = APIntOps::RoundFloatToAPInt(Src.FloatVal, DBitWidth);
1013   else
1014     Dest.IntVal = APIntOps::RoundDoubleToAPInt(Src.DoubleVal, DBitWidth);
1015   return Dest;
1016 }
1017
1018 GenericValue Interpreter::executeUIToFPInst(Value *SrcVal, const Type *DstTy,
1019                                             ExecutionContext &SF) {
1020   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1021   assert(DstTy->isFloatingPoint() && "Invalid UIToFP instruction");
1022
1023   if (DstTy->getTypeID() == Type::FloatTyID)
1024     Dest.FloatVal = APIntOps::RoundAPIntToFloat(Src.IntVal);
1025   else
1026     Dest.DoubleVal = APIntOps::RoundAPIntToDouble(Src.IntVal);
1027   return Dest;
1028 }
1029
1030 GenericValue Interpreter::executeSIToFPInst(Value *SrcVal, const Type *DstTy,
1031                                             ExecutionContext &SF) {
1032   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1033   assert(DstTy->isFloatingPoint() && "Invalid SIToFP instruction");
1034
1035   if (DstTy->getTypeID() == Type::FloatTyID)
1036     Dest.FloatVal = APIntOps::RoundSignedAPIntToFloat(Src.IntVal);
1037   else
1038     Dest.DoubleVal = APIntOps::RoundSignedAPIntToDouble(Src.IntVal);
1039   return Dest;
1040
1041 }
1042
1043 GenericValue Interpreter::executePtrToIntInst(Value *SrcVal, const Type *DstTy,
1044                                               ExecutionContext &SF) {
1045   uint32_t DBitWidth = cast<IntegerType>(DstTy)->getBitWidth();
1046   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1047   assert(isa<PointerType>(SrcVal->getType()) && "Invalid PtrToInt instruction");
1048
1049   Dest.IntVal = APInt(DBitWidth, (intptr_t) Src.PointerVal);
1050   return Dest;
1051 }
1052
1053 GenericValue Interpreter::executeIntToPtrInst(Value *SrcVal, const Type *DstTy,
1054                                               ExecutionContext &SF) {
1055   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1056   assert(isa<PointerType>(DstTy) && "Invalid PtrToInt instruction");
1057
1058   uint32_t PtrSize = TD.getPointerSizeInBits();
1059   if (PtrSize != Src.IntVal.getBitWidth())
1060     Src.IntVal = Src.IntVal.zextOrTrunc(PtrSize);
1061
1062   Dest.PointerVal = PointerTy(intptr_t(Src.IntVal.getZExtValue()));
1063   return Dest;
1064 }
1065
1066 GenericValue Interpreter::executeBitCastInst(Value *SrcVal, const Type *DstTy,
1067                                              ExecutionContext &SF) {
1068
1069   const Type *SrcTy = SrcVal->getType();
1070   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1071   if (isa<PointerType>(DstTy)) {
1072     assert(isa<PointerType>(SrcTy) && "Invalid BitCast");
1073     Dest.PointerVal = Src.PointerVal;
1074   } else if (DstTy->isInteger()) {
1075     if (SrcTy == Type::getFloatTy(SrcVal->getContext())) {
1076       Dest.IntVal.zext(sizeof(Src.FloatVal) * CHAR_BIT);
1077       Dest.IntVal.floatToBits(Src.FloatVal);
1078     } else if (SrcTy == Type::getDoubleTy(SrcVal->getContext())) {
1079       Dest.IntVal.zext(sizeof(Src.DoubleVal) * CHAR_BIT);
1080       Dest.IntVal.doubleToBits(Src.DoubleVal);
1081     } else if (SrcTy->isInteger()) {
1082       Dest.IntVal = Src.IntVal;
1083     } else
1084       llvm_unreachable("Invalid BitCast");
1085   } else if (DstTy == Type::getFloatTy(SrcVal->getContext())) {
1086     if (SrcTy->isInteger())
1087       Dest.FloatVal = Src.IntVal.bitsToFloat();
1088     else
1089       Dest.FloatVal = Src.FloatVal;
1090   } else if (DstTy == Type::getDoubleTy(SrcVal->getContext())) {
1091     if (SrcTy->isInteger())
1092       Dest.DoubleVal = Src.IntVal.bitsToDouble();
1093     else
1094       Dest.DoubleVal = Src.DoubleVal;
1095   } else
1096     llvm_unreachable("Invalid Bitcast");
1097
1098   return Dest;
1099 }
1100
1101 void Interpreter::visitTruncInst(TruncInst &I) {
1102   ExecutionContext &SF = ECStack.back();
1103   SetValue(&I, executeTruncInst(I.getOperand(0), I.getType(), SF), SF);
1104 }
1105
1106 void Interpreter::visitSExtInst(SExtInst &I) {
1107   ExecutionContext &SF = ECStack.back();
1108   SetValue(&I, executeSExtInst(I.getOperand(0), I.getType(), SF), SF);
1109 }
1110
1111 void Interpreter::visitZExtInst(ZExtInst &I) {
1112   ExecutionContext &SF = ECStack.back();
1113   SetValue(&I, executeZExtInst(I.getOperand(0), I.getType(), SF), SF);
1114 }
1115
1116 void Interpreter::visitFPTruncInst(FPTruncInst &I) {
1117   ExecutionContext &SF = ECStack.back();
1118   SetValue(&I, executeFPTruncInst(I.getOperand(0), I.getType(), SF), SF);
1119 }
1120
1121 void Interpreter::visitFPExtInst(FPExtInst &I) {
1122   ExecutionContext &SF = ECStack.back();
1123   SetValue(&I, executeFPExtInst(I.getOperand(0), I.getType(), SF), SF);
1124 }
1125
1126 void Interpreter::visitUIToFPInst(UIToFPInst &I) {
1127   ExecutionContext &SF = ECStack.back();
1128   SetValue(&I, executeUIToFPInst(I.getOperand(0), I.getType(), SF), SF);
1129 }
1130
1131 void Interpreter::visitSIToFPInst(SIToFPInst &I) {
1132   ExecutionContext &SF = ECStack.back();
1133   SetValue(&I, executeSIToFPInst(I.getOperand(0), I.getType(), SF), SF);
1134 }
1135
1136 void Interpreter::visitFPToUIInst(FPToUIInst &I) {
1137   ExecutionContext &SF = ECStack.back();
1138   SetValue(&I, executeFPToUIInst(I.getOperand(0), I.getType(), SF), SF);
1139 }
1140
1141 void Interpreter::visitFPToSIInst(FPToSIInst &I) {
1142   ExecutionContext &SF = ECStack.back();
1143   SetValue(&I, executeFPToSIInst(I.getOperand(0), I.getType(), SF), SF);
1144 }
1145
1146 void Interpreter::visitPtrToIntInst(PtrToIntInst &I) {
1147   ExecutionContext &SF = ECStack.back();
1148   SetValue(&I, executePtrToIntInst(I.getOperand(0), I.getType(), SF), SF);
1149 }
1150
1151 void Interpreter::visitIntToPtrInst(IntToPtrInst &I) {
1152   ExecutionContext &SF = ECStack.back();
1153   SetValue(&I, executeIntToPtrInst(I.getOperand(0), I.getType(), SF), SF);
1154 }
1155
1156 void Interpreter::visitBitCastInst(BitCastInst &I) {
1157   ExecutionContext &SF = ECStack.back();
1158   SetValue(&I, executeBitCastInst(I.getOperand(0), I.getType(), SF), SF);
1159 }
1160
1161 #define IMPLEMENT_VAARG(TY) \
1162    case Type::TY##TyID: Dest.TY##Val = Src.TY##Val; break
1163
1164 void Interpreter::visitVAArgInst(VAArgInst &I) {
1165   ExecutionContext &SF = ECStack.back();
1166
1167   // Get the incoming valist parameter.  LLI treats the valist as a
1168   // (ec-stack-depth var-arg-index) pair.
1169   GenericValue VAList = getOperandValue(I.getOperand(0), SF);
1170   GenericValue Dest;
1171   GenericValue Src = ECStack[VAList.UIntPairVal.first]
1172                       .VarArgs[VAList.UIntPairVal.second];
1173   const Type *Ty = I.getType();
1174   switch (Ty->getTypeID()) {
1175     case Type::IntegerTyID: Dest.IntVal = Src.IntVal;
1176     IMPLEMENT_VAARG(Pointer);
1177     IMPLEMENT_VAARG(Float);
1178     IMPLEMENT_VAARG(Double);
1179   default:
1180     errs() << "Unhandled dest type for vaarg instruction: " << *Ty << "\n";
1181     llvm_unreachable(0);
1182   }
1183
1184   // Set the Value of this Instruction.
1185   SetValue(&I, Dest, SF);
1186
1187   // Move the pointer to the next vararg.
1188   ++VAList.UIntPairVal.second;
1189 }
1190
1191 GenericValue Interpreter::getConstantExprValue (ConstantExpr *CE,
1192                                                 ExecutionContext &SF) {
1193   switch (CE->getOpcode()) {
1194   case Instruction::Trunc:
1195       return executeTruncInst(CE->getOperand(0), CE->getType(), SF);
1196   case Instruction::ZExt:
1197       return executeZExtInst(CE->getOperand(0), CE->getType(), SF);
1198   case Instruction::SExt:
1199       return executeSExtInst(CE->getOperand(0), CE->getType(), SF);
1200   case Instruction::FPTrunc:
1201       return executeFPTruncInst(CE->getOperand(0), CE->getType(), SF);
1202   case Instruction::FPExt:
1203       return executeFPExtInst(CE->getOperand(0), CE->getType(), SF);
1204   case Instruction::UIToFP:
1205       return executeUIToFPInst(CE->getOperand(0), CE->getType(), SF);
1206   case Instruction::SIToFP:
1207       return executeSIToFPInst(CE->getOperand(0), CE->getType(), SF);
1208   case Instruction::FPToUI:
1209       return executeFPToUIInst(CE->getOperand(0), CE->getType(), SF);
1210   case Instruction::FPToSI:
1211       return executeFPToSIInst(CE->getOperand(0), CE->getType(), SF);
1212   case Instruction::PtrToInt:
1213       return executePtrToIntInst(CE->getOperand(0), CE->getType(), SF);
1214   case Instruction::IntToPtr:
1215       return executeIntToPtrInst(CE->getOperand(0), CE->getType(), SF);
1216   case Instruction::BitCast:
1217       return executeBitCastInst(CE->getOperand(0), CE->getType(), SF);
1218   case Instruction::GetElementPtr:
1219     return executeGEPOperation(CE->getOperand(0), gep_type_begin(CE),
1220                                gep_type_end(CE), SF);
1221   case Instruction::FCmp:
1222   case Instruction::ICmp:
1223     return executeCmpInst(CE->getPredicate(),
1224                           getOperandValue(CE->getOperand(0), SF),
1225                           getOperandValue(CE->getOperand(1), SF),
1226                           CE->getOperand(0)->getType());
1227   case Instruction::Select:
1228     return executeSelectInst(getOperandValue(CE->getOperand(0), SF),
1229                              getOperandValue(CE->getOperand(1), SF),
1230                              getOperandValue(CE->getOperand(2), SF));
1231   default :
1232     break;
1233   }
1234
1235   // The cases below here require a GenericValue parameter for the result
1236   // so we initialize one, compute it and then return it.
1237   GenericValue Op0 = getOperandValue(CE->getOperand(0), SF);
1238   GenericValue Op1 = getOperandValue(CE->getOperand(1), SF);
1239   GenericValue Dest;
1240   const Type * Ty = CE->getOperand(0)->getType();
1241   switch (CE->getOpcode()) {
1242   case Instruction::Add:  Dest.IntVal = Op0.IntVal + Op1.IntVal; break;
1243   case Instruction::Sub:  Dest.IntVal = Op0.IntVal - Op1.IntVal; break;
1244   case Instruction::Mul:  Dest.IntVal = Op0.IntVal * Op1.IntVal; break;
1245   case Instruction::FAdd: executeFAddInst(Dest, Op0, Op1, Ty); break;
1246   case Instruction::FSub: executeFSubInst(Dest, Op0, Op1, Ty); break;
1247   case Instruction::FMul: executeFMulInst(Dest, Op0, Op1, Ty); break;
1248   case Instruction::FDiv: executeFDivInst(Dest, Op0, Op1, Ty); break;
1249   case Instruction::FRem: executeFRemInst(Dest, Op0, Op1, Ty); break;
1250   case Instruction::SDiv: Dest.IntVal = Op0.IntVal.sdiv(Op1.IntVal); break;
1251   case Instruction::UDiv: Dest.IntVal = Op0.IntVal.udiv(Op1.IntVal); break;
1252   case Instruction::URem: Dest.IntVal = Op0.IntVal.urem(Op1.IntVal); break;
1253   case Instruction::SRem: Dest.IntVal = Op0.IntVal.srem(Op1.IntVal); break;
1254   case Instruction::And:  Dest.IntVal = Op0.IntVal & Op1.IntVal; break;
1255   case Instruction::Or:   Dest.IntVal = Op0.IntVal | Op1.IntVal; break;
1256   case Instruction::Xor:  Dest.IntVal = Op0.IntVal ^ Op1.IntVal; break;
1257   case Instruction::Shl:
1258     Dest.IntVal = Op0.IntVal.shl(Op1.IntVal.getZExtValue());
1259     break;
1260   case Instruction::LShr:
1261     Dest.IntVal = Op0.IntVal.lshr(Op1.IntVal.getZExtValue());
1262     break;
1263   case Instruction::AShr:
1264     Dest.IntVal = Op0.IntVal.ashr(Op1.IntVal.getZExtValue());
1265     break;
1266   default:
1267     errs() << "Unhandled ConstantExpr: " << *CE << "\n";
1268     llvm_unreachable(0);
1269     return GenericValue();
1270   }
1271   return Dest;
1272 }
1273
1274 GenericValue Interpreter::getOperandValue(Value *V, ExecutionContext &SF) {
1275   if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
1276     return getConstantExprValue(CE, SF);
1277   } else if (Constant *CPV = dyn_cast<Constant>(V)) {
1278     return getConstantValue(CPV);
1279   } else if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
1280     return PTOGV(getPointerToGlobal(GV));
1281   } else {
1282     return SF.Values[V];
1283   }
1284 }
1285
1286 //===----------------------------------------------------------------------===//
1287 //                        Dispatch and Execution Code
1288 //===----------------------------------------------------------------------===//
1289
1290 //===----------------------------------------------------------------------===//
1291 // callFunction - Execute the specified function...
1292 //
1293 void Interpreter::callFunction(Function *F,
1294                                const std::vector<GenericValue> &ArgVals) {
1295   assert((ECStack.empty() || ECStack.back().Caller.getInstruction() == 0 ||
1296           ECStack.back().Caller.arg_size() == ArgVals.size()) &&
1297          "Incorrect number of arguments passed into function call!");
1298   // Make a new stack frame... and fill it in.
1299   ECStack.push_back(ExecutionContext());
1300   ExecutionContext &StackFrame = ECStack.back();
1301   StackFrame.CurFunction = F;
1302
1303   // Special handling for external functions.
1304   if (F->isDeclaration()) {
1305     GenericValue Result = callExternalFunction (F, ArgVals);
1306     // Simulate a 'ret' instruction of the appropriate type.
1307     popStackAndReturnValueToCaller (F->getReturnType (), Result);
1308     return;
1309   }
1310
1311   // Get pointers to first LLVM BB & Instruction in function.
1312   StackFrame.CurBB     = F->begin();
1313   StackFrame.CurInst   = StackFrame.CurBB->begin();
1314
1315   // Run through the function arguments and initialize their values...
1316   assert((ArgVals.size() == F->arg_size() ||
1317          (ArgVals.size() > F->arg_size() && F->getFunctionType()->isVarArg()))&&
1318          "Invalid number of values passed to function invocation!");
1319
1320   // Handle non-varargs arguments...
1321   unsigned i = 0;
1322   for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end();
1323        AI != E; ++AI, ++i)
1324     SetValue(AI, ArgVals[i], StackFrame);
1325
1326   // Handle varargs arguments...
1327   StackFrame.VarArgs.assign(ArgVals.begin()+i, ArgVals.end());
1328 }
1329
1330
1331 void Interpreter::run() {
1332   while (!ECStack.empty()) {
1333     // Interpret a single instruction & increment the "PC".
1334     ExecutionContext &SF = ECStack.back();  // Current stack frame
1335     Instruction &I = *SF.CurInst++;         // Increment before execute
1336
1337     // Track the number of dynamic instructions executed.
1338     ++NumDynamicInsts;
1339
1340     DEBUG(errs() << "About to interpret: " << I);
1341     visit(I);   // Dispatch to one of the visit* methods...
1342 #if 0
1343     // This is not safe, as visiting the instruction could lower it and free I.
1344 DEBUG(
1345     if (!isa<CallInst>(I) && !isa<InvokeInst>(I) &&
1346         I.getType() != Type::VoidTy) {
1347       errs() << "  --> ";
1348       const GenericValue &Val = SF.Values[&I];
1349       switch (I.getType()->getTypeID()) {
1350       default: llvm_unreachable("Invalid GenericValue Type");
1351       case Type::VoidTyID:    errs() << "void"; break;
1352       case Type::FloatTyID:   errs() << "float " << Val.FloatVal; break;
1353       case Type::DoubleTyID:  errs() << "double " << Val.DoubleVal; break;
1354       case Type::PointerTyID: errs() << "void* " << intptr_t(Val.PointerVal);
1355         break;
1356       case Type::IntegerTyID:
1357         errs() << "i" << Val.IntVal.getBitWidth() << " "
1358                << Val.IntVal.toStringUnsigned(10)
1359                << " (0x" << Val.IntVal.toStringUnsigned(16) << ")\n";
1360         break;
1361       }
1362     });
1363 #endif
1364   }
1365 }