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>
29using namespace llvm;
30
31STATISTIC(NumDynamicInsts, "Number of dynamic instructions executed");
32
33static 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
40static 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
53static void executeFAddInst(GenericValue &Dest, GenericValue Src1,
54                            GenericValue Src2, 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
64static void executeFSubInst(GenericValue &Dest, GenericValue Src1,
65                            GenericValue Src2, 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
75static void executeFMulInst(GenericValue &Dest, GenericValue Src1,
76                            GenericValue Src2, 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
86static void executeFDivInst(GenericValue &Dest, GenericValue Src1,
87                            GenericValue Src2, 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
97static void executeFRemInst(GenericValue &Dest, GenericValue Src1,
98                            GenericValue Src2, 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
127static GenericValue executeICMP_EQ(GenericValue Src1, GenericValue Src2,
128                                   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
140static GenericValue executeICMP_NE(GenericValue Src1, GenericValue Src2,
141                                   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
153static GenericValue executeICMP_ULT(GenericValue Src1, GenericValue Src2,
154                                    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
166static GenericValue executeICMP_SLT(GenericValue Src1, GenericValue Src2,
167                                    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
179static GenericValue executeICMP_UGT(GenericValue Src1, GenericValue Src2,
180                                    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
192static GenericValue executeICMP_SGT(GenericValue Src1, GenericValue Src2,
193                                    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
205static GenericValue executeICMP_ULE(GenericValue Src1, GenericValue Src2,
206                                    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
218static GenericValue executeICMP_SLE(GenericValue Src1, GenericValue Src2,
219                                    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
231static GenericValue executeICMP_UGE(GenericValue Src1, GenericValue Src2,
232                                    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
244static GenericValue executeICMP_SGE(GenericValue Src1, GenericValue Src2,
245                                    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
257void Interpreter::visitICmpInst(ICmpInst &I) {
258  ExecutionContext &SF = ECStack.back();
259  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
288static GenericValue executeFCMP_OEQ(GenericValue Src1, GenericValue Src2,
289                                   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
301static GenericValue executeFCMP_ONE(GenericValue Src1, GenericValue Src2,
302                                   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
315static GenericValue executeFCMP_OLE(GenericValue Src1, GenericValue Src2,
316                                   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
328static GenericValue executeFCMP_OGE(GenericValue Src1, GenericValue Src2,
329                                   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
341static GenericValue executeFCMP_OLT(GenericValue Src1, GenericValue Src2,
342                                   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
354static GenericValue executeFCMP_OGT(GenericValue Src1, GenericValue Src2,
355                                     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
379static GenericValue executeFCMP_UEQ(GenericValue Src1, GenericValue Src2,
380                                   Type *Ty) {
381  GenericValue Dest;
382  IMPLEMENT_UNORDERED(Ty, Src1, Src2)
383  return executeFCMP_OEQ(Src1, Src2, Ty);
384}
385
386static GenericValue executeFCMP_UNE(GenericValue Src1, GenericValue Src2,
387                                   Type *Ty) {
388  GenericValue Dest;
389  IMPLEMENT_UNORDERED(Ty, Src1, Src2)
390  return executeFCMP_ONE(Src1, Src2, Ty);
391}
392
393static GenericValue executeFCMP_ULE(GenericValue Src1, GenericValue Src2,
394                                   Type *Ty) {
395  GenericValue Dest;
396  IMPLEMENT_UNORDERED(Ty, Src1, Src2)
397  return executeFCMP_OLE(Src1, Src2, Ty);
398}
399
400static GenericValue executeFCMP_UGE(GenericValue Src1, GenericValue Src2,
401                                   Type *Ty) {
402  GenericValue Dest;
403  IMPLEMENT_UNORDERED(Ty, Src1, Src2)
404  return executeFCMP_OGE(Src1, Src2, Ty);
405}
406
407static GenericValue executeFCMP_ULT(GenericValue Src1, GenericValue Src2,
408                                   Type *Ty) {
409  GenericValue Dest;
410  IMPLEMENT_UNORDERED(Ty, Src1, Src2)
411  return executeFCMP_OLT(Src1, Src2, Ty);
412}
413
414static GenericValue executeFCMP_UGT(GenericValue Src1, GenericValue Src2,
415                                     Type *Ty) {
416  GenericValue Dest;
417  IMPLEMENT_UNORDERED(Ty, Src1, Src2)
418  return executeFCMP_OGT(Src1, Src2, Ty);
419}
420
421static GenericValue executeFCMP_ORD(GenericValue Src1, GenericValue Src2,
422                                     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
433static GenericValue executeFCMP_UNO(GenericValue Src1, GenericValue Src2,
434                                     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
445void Interpreter::visitFCmpInst(FCmpInst &I) {
446  ExecutionContext &SF = ECStack.back();
447  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
477static GenericValue executeCmpInst(unsigned predicate, GenericValue Src1,
478                                   GenericValue Src2, 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
521void Interpreter::visitBinaryOperator(BinaryOperator &I) {
522  ExecutionContext &SF = ECStack.back();
523  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
552static GenericValue executeSelectInst(GenericValue Src1, GenericValue Src2,
553                                      GenericValue Src3) {
554  return Src1.IntVal == 0 ? Src3 : Src2;
555}
556
557void 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
571void 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///
588void Interpreter::popStackAndReturnValueToCaller(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
614void Interpreter::visitReturnInst(ReturnInst &I) {
615  ExecutionContext &SF = ECStack.back();
616  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
628void Interpreter::visitUnreachableInst(UnreachableInst &I) {
629  report_fatal_error("Program executed an 'unreachable' instruction!");
630}
631
632void Interpreter::visitBranchInst(BranchInst &I) {
633  ExecutionContext &SF = ECStack.back();
634  BasicBlock *Dest;
635
636  Dest = I.getSuccessor(0);          // Uncond branches have a fixed dest...
637  if (!I.isUnconditional()) {
638    Value *Cond = I.getCondition();
639    if (getOperandValue(Cond, SF).IntVal == 0) // If false cond...
640      Dest = I.getSuccessor(1);
641  }
642  SwitchToNewBasicBlock(Dest, SF);
643}
644
645void Interpreter::visitSwitchInst(SwitchInst &I) {
646  ExecutionContext &SF = ECStack.back();
647  Value* Cond = I.getCondition();
648  Type *ElTy = Cond->getType();
649  GenericValue CondVal = getOperandValue(Cond, SF);
650
651  // Check to see if any of the cases match...
652  BasicBlock *Dest = 0;
653  for (SwitchInst::CaseIt i = I.case_begin(), e = I.case_end(); i != e; ++i) {
654    GenericValue CaseVal = getOperandValue(i.getCaseValue(), SF);
655    if (executeICMP_EQ(CondVal, CaseVal, ElTy).IntVal != 0) {
656      Dest = cast<BasicBlock>(i.getCaseSuccessor());
657      break;
658    }
659  }
660  if (!Dest) Dest = I.getDefaultDest();   // No cases matched: use default
661  SwitchToNewBasicBlock(Dest, SF);
662}
663
664void Interpreter::visitIndirectBrInst(IndirectBrInst &I) {
665  ExecutionContext &SF = ECStack.back();
666  void *Dest = GVTOP(getOperandValue(I.getAddress(), SF));
667  SwitchToNewBasicBlock((BasicBlock*)Dest, SF);
668}
669
670
671// SwitchToNewBasicBlock - This method is used to jump to a new basic block.
672// This function handles the actual updating of block and instruction iterators
673// as well as execution of all of the PHI nodes in the destination block.
674//
675// This method does this because all of the PHI nodes must be executed
676// atomically, reading their inputs before any of the results are updated.  Not
677// doing this can cause problems if the PHI nodes depend on other PHI nodes for
678// their inputs.  If the input PHI node is updated before it is read, incorrect
679// results can happen.  Thus we use a two phase approach.
680//
681void Interpreter::SwitchToNewBasicBlock(BasicBlock *Dest, ExecutionContext &SF){
682  BasicBlock *PrevBB = SF.CurBB;      // Remember where we came from...
683  SF.CurBB   = Dest;                  // Update CurBB to branch destination
684  SF.CurInst = SF.CurBB->begin();     // Update new instruction ptr...
685
686  if (!isa<PHINode>(SF.CurInst)) return;  // Nothing fancy to do
687
688  // Loop over all of the PHI nodes in the current block, reading their inputs.
689  std::vector<GenericValue> ResultValues;
690
691  for (; PHINode *PN = dyn_cast<PHINode>(SF.CurInst); ++SF.CurInst) {
692    // Search for the value corresponding to this previous bb...
693    int i = PN->getBasicBlockIndex(PrevBB);
694    assert(i != -1 && "PHINode doesn't contain entry for predecessor??");
695    Value *IncomingValue = PN->getIncomingValue(i);
696
697    // Save the incoming value for this PHI node...
698    ResultValues.push_back(getOperandValue(IncomingValue, SF));
699  }
700
701  // Now loop over all of the PHI nodes setting their values...
702  SF.CurInst = SF.CurBB->begin();
703  for (unsigned i = 0; isa<PHINode>(SF.CurInst); ++SF.CurInst, ++i) {
704    PHINode *PN = cast<PHINode>(SF.CurInst);
705    SetValue(PN, ResultValues[i], SF);
706  }
707}
708
709//===----------------------------------------------------------------------===//
710//                     Memory Instruction Implementations
711//===----------------------------------------------------------------------===//
712
713void Interpreter::visitAllocaInst(AllocaInst &I) {
714  ExecutionContext &SF = ECStack.back();
715
716  Type *Ty = I.getType()->getElementType();  // Type to be allocated
717
718  // Get the number of elements being allocated by the array...
719  unsigned NumElements =
720    getOperandValue(I.getOperand(0), SF).IntVal.getZExtValue();
721
722  unsigned TypeSize = (size_t)TD.getTypeAllocSize(Ty);
723
724  // Avoid malloc-ing zero bytes, use max()...
725  unsigned MemToAlloc = std::max(1U, NumElements * TypeSize);
726
727  // Allocate enough memory to hold the type...
728  void *Memory = malloc(MemToAlloc);
729
730  DEBUG(dbgs() << "Allocated Type: " << *Ty << " (" << TypeSize << " bytes) x "
731               << NumElements << " (Total: " << MemToAlloc << ") at "
732               << uintptr_t(Memory) << '\n');
733
734  GenericValue Result = PTOGV(Memory);
735  assert(Result.PointerVal != 0 && "Null pointer returned by malloc!");
736  SetValue(&I, Result, SF);
737
738  if (I.getOpcode() == Instruction::Alloca)
739    ECStack.back().Allocas.add(Memory);
740}
741
742// getElementOffset - The workhorse for getelementptr.
743//
744GenericValue Interpreter::executeGEPOperation(Value *Ptr, gep_type_iterator I,
745                                              gep_type_iterator E,
746                                              ExecutionContext &SF) {
747  assert(Ptr->getType()->isPointerTy() &&
748         "Cannot getElementOffset of a nonpointer type!");
749
750  uint64_t Total = 0;
751
752  for (; I != E; ++I) {
753    if (StructType *STy = dyn_cast<StructType>(*I)) {
754      const StructLayout *SLO = TD.getStructLayout(STy);
755
756      const ConstantInt *CPU = cast<ConstantInt>(I.getOperand());
757      unsigned Index = unsigned(CPU->getZExtValue());
758
759      Total += SLO->getElementOffset(Index);
760    } else {
761      SequentialType *ST = cast<SequentialType>(*I);
762      // Get the index number for the array... which must be long type...
763      GenericValue IdxGV = getOperandValue(I.getOperand(), SF);
764
765      int64_t Idx;
766      unsigned BitWidth =
767        cast<IntegerType>(I.getOperand()->getType())->getBitWidth();
768      if (BitWidth == 32)
769        Idx = (int64_t)(int32_t)IdxGV.IntVal.getZExtValue();
770      else {
771        assert(BitWidth == 64 && "Invalid index type for getelementptr");
772        Idx = (int64_t)IdxGV.IntVal.getZExtValue();
773      }
774      Total += TD.getTypeAllocSize(ST->getElementType())*Idx;
775    }
776  }
777
778  GenericValue Result;
779  Result.PointerVal = ((char*)getOperandValue(Ptr, SF).PointerVal) + Total;
780  DEBUG(dbgs() << "GEP Index " << Total << " bytes.\n");
781  return Result;
782}
783
784void Interpreter::visitGetElementPtrInst(GetElementPtrInst &I) {
785  ExecutionContext &SF = ECStack.back();
786  SetValue(&I, executeGEPOperation(I.getPointerOperand(),
787                                   gep_type_begin(I), gep_type_end(I), SF), SF);
788}
789
790void Interpreter::visitLoadInst(LoadInst &I) {
791  ExecutionContext &SF = ECStack.back();
792  GenericValue SRC = getOperandValue(I.getPointerOperand(), SF);
793  GenericValue *Ptr = (GenericValue*)GVTOP(SRC);
794  GenericValue Result;
795  LoadValueFromMemory(Result, Ptr, I.getType());
796  SetValue(&I, Result, SF);
797  if (I.isVolatile() && PrintVolatile)
798    dbgs() << "Volatile load " << I;
799}
800
801void Interpreter::visitStoreInst(StoreInst &I) {
802  ExecutionContext &SF = ECStack.back();
803  GenericValue Val = getOperandValue(I.getOperand(0), SF);
804  GenericValue SRC = getOperandValue(I.getPointerOperand(), SF);
805  StoreValueToMemory(Val, (GenericValue *)GVTOP(SRC),
806                     I.getOperand(0)->getType());
807  if (I.isVolatile() && PrintVolatile)
808    dbgs() << "Volatile store: " << I;
809}
810
811//===----------------------------------------------------------------------===//
812//                 Miscellaneous Instruction Implementations
813//===----------------------------------------------------------------------===//
814
815void Interpreter::visitCallSite(CallSite CS) {
816  ExecutionContext &SF = ECStack.back();
817
818  // Check to see if this is an intrinsic function call...
819  Function *F = CS.getCalledFunction();
820  if (F && F->isDeclaration())
821    switch (F->getIntrinsicID()) {
822    case Intrinsic::not_intrinsic:
823      break;
824    case Intrinsic::vastart: { // va_start
825      GenericValue ArgIndex;
826      ArgIndex.UIntPairVal.first = ECStack.size() - 1;
827      ArgIndex.UIntPairVal.second = 0;
828      SetValue(CS.getInstruction(), ArgIndex, SF);
829      return;
830    }
831    case Intrinsic::vaend:    // va_end is a noop for the interpreter
832      return;
833    case Intrinsic::vacopy:   // va_copy: dest = src
834      SetValue(CS.getInstruction(), getOperandValue(*CS.arg_begin(), SF), SF);
835      return;
836    default:
837      // If it is an unknown intrinsic function, use the intrinsic lowering
838      // class to transform it into hopefully tasty LLVM code.
839      //
840      BasicBlock::iterator me(CS.getInstruction());
841      BasicBlock *Parent = CS.getInstruction()->getParent();
842      bool atBegin(Parent->begin() == me);
843      if (!atBegin)
844        --me;
845      IL->LowerIntrinsicCall(cast<CallInst>(CS.getInstruction()));
846
847      // Restore the CurInst pointer to the first instruction newly inserted, if
848      // any.
849      if (atBegin) {
850        SF.CurInst = Parent->begin();
851      } else {
852        SF.CurInst = me;
853        ++SF.CurInst;
854      }
855      return;
856    }
857
858
859  SF.Caller = CS;
860  std::vector<GenericValue> ArgVals;
861  const unsigned NumArgs = SF.Caller.arg_size();
862  ArgVals.reserve(NumArgs);
863  uint16_t pNum = 1;
864  for (CallSite::arg_iterator i = SF.Caller.arg_begin(),
865         e = SF.Caller.arg_end(); i != e; ++i, ++pNum) {
866    Value *V = *i;
867    ArgVals.push_back(getOperandValue(V, SF));
868  }
869
870  // To handle indirect calls, we must get the pointer value from the argument
871  // and treat it as a function pointer.
872  GenericValue SRC = getOperandValue(SF.Caller.getCalledValue(), SF);
873  callFunction((Function*)GVTOP(SRC), ArgVals);
874}
875
876void Interpreter::visitShl(BinaryOperator &I) {
877  ExecutionContext &SF = ECStack.back();
878  GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
879  GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
880  GenericValue Dest;
881  if (Src2.IntVal.getZExtValue() < Src1.IntVal.getBitWidth())
882    Dest.IntVal = Src1.IntVal.shl(Src2.IntVal.getZExtValue());
883  else
884    Dest.IntVal = Src1.IntVal;
885
886  SetValue(&I, Dest, SF);
887}
888
889void Interpreter::visitLShr(BinaryOperator &I) {
890  ExecutionContext &SF = ECStack.back();
891  GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
892  GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
893  GenericValue Dest;
894  if (Src2.IntVal.getZExtValue() < Src1.IntVal.getBitWidth())
895    Dest.IntVal = Src1.IntVal.lshr(Src2.IntVal.getZExtValue());
896  else
897    Dest.IntVal = Src1.IntVal;
898
899  SetValue(&I, Dest, SF);
900}
901
902void Interpreter::visitAShr(BinaryOperator &I) {
903  ExecutionContext &SF = ECStack.back();
904  GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
905  GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
906  GenericValue Dest;
907  if (Src2.IntVal.getZExtValue() < Src1.IntVal.getBitWidth())
908    Dest.IntVal = Src1.IntVal.ashr(Src2.IntVal.getZExtValue());
909  else
910    Dest.IntVal = Src1.IntVal;
911
912  SetValue(&I, Dest, SF);
913}
914
915GenericValue Interpreter::executeTruncInst(Value *SrcVal, Type *DstTy,
916                                           ExecutionContext &SF) {
917  GenericValue Dest, Src = getOperandValue(SrcVal, SF);
918  IntegerType *DITy = cast<IntegerType>(DstTy);
919  unsigned DBitWidth = DITy->getBitWidth();
920  Dest.IntVal = Src.IntVal.trunc(DBitWidth);
921  return Dest;
922}
923
924GenericValue Interpreter::executeSExtInst(Value *SrcVal, Type *DstTy,
925                                          ExecutionContext &SF) {
926  GenericValue Dest, Src = getOperandValue(SrcVal, SF);
927  IntegerType *DITy = cast<IntegerType>(DstTy);
928  unsigned DBitWidth = DITy->getBitWidth();
929  Dest.IntVal = Src.IntVal.sext(DBitWidth);
930  return Dest;
931}
932
933GenericValue Interpreter::executeZExtInst(Value *SrcVal, Type *DstTy,
934                                          ExecutionContext &SF) {
935  GenericValue Dest, Src = getOperandValue(SrcVal, SF);
936  IntegerType *DITy = cast<IntegerType>(DstTy);
937  unsigned DBitWidth = DITy->getBitWidth();
938  Dest.IntVal = Src.IntVal.zext(DBitWidth);
939  return Dest;
940}
941
942GenericValue Interpreter::executeFPTruncInst(Value *SrcVal, Type *DstTy,
943                                             ExecutionContext &SF) {
944  GenericValue Dest, Src = getOperandValue(SrcVal, SF);
945  assert(SrcVal->getType()->isDoubleTy() && DstTy->isFloatTy() &&
946         "Invalid FPTrunc instruction");
947  Dest.FloatVal = (float) Src.DoubleVal;
948  return Dest;
949}
950
951GenericValue Interpreter::executeFPExtInst(Value *SrcVal, Type *DstTy,
952                                           ExecutionContext &SF) {
953  GenericValue Dest, Src = getOperandValue(SrcVal, SF);
954  assert(SrcVal->getType()->isFloatTy() && DstTy->isDoubleTy() &&
955         "Invalid FPTrunc instruction");
956  Dest.DoubleVal = (double) Src.FloatVal;
957  return Dest;
958}
959
960GenericValue Interpreter::executeFPToUIInst(Value *SrcVal, Type *DstTy,
961                                            ExecutionContext &SF) {
962  Type *SrcTy = SrcVal->getType();
963  uint32_t DBitWidth = cast<IntegerType>(DstTy)->getBitWidth();
964  GenericValue Dest, Src = getOperandValue(SrcVal, SF);
965  assert(SrcTy->isFloatingPointTy() && "Invalid FPToUI instruction");
966
967  if (SrcTy->getTypeID() == Type::FloatTyID)
968    Dest.IntVal = APIntOps::RoundFloatToAPInt(Src.FloatVal, DBitWidth);
969  else
970    Dest.IntVal = APIntOps::RoundDoubleToAPInt(Src.DoubleVal, DBitWidth);
971  return Dest;
972}
973
974GenericValue Interpreter::executeFPToSIInst(Value *SrcVal, Type *DstTy,
975                                            ExecutionContext &SF) {
976  Type *SrcTy = SrcVal->getType();
977  uint32_t DBitWidth = cast<IntegerType>(DstTy)->getBitWidth();
978  GenericValue Dest, Src = getOperandValue(SrcVal, SF);
979  assert(SrcTy->isFloatingPointTy() && "Invalid FPToSI instruction");
980
981  if (SrcTy->getTypeID() == Type::FloatTyID)
982    Dest.IntVal = APIntOps::RoundFloatToAPInt(Src.FloatVal, DBitWidth);
983  else
984    Dest.IntVal = APIntOps::RoundDoubleToAPInt(Src.DoubleVal, DBitWidth);
985  return Dest;
986}
987
988GenericValue Interpreter::executeUIToFPInst(Value *SrcVal, Type *DstTy,
989                                            ExecutionContext &SF) {
990  GenericValue Dest, Src = getOperandValue(SrcVal, SF);
991  assert(DstTy->isFloatingPointTy() && "Invalid UIToFP instruction");
992
993  if (DstTy->getTypeID() == Type::FloatTyID)
994    Dest.FloatVal = APIntOps::RoundAPIntToFloat(Src.IntVal);
995  else
996    Dest.DoubleVal = APIntOps::RoundAPIntToDouble(Src.IntVal);
997  return Dest;
998}
999
1000GenericValue Interpreter::executeSIToFPInst(Value *SrcVal, Type *DstTy,
1001                                            ExecutionContext &SF) {
1002  GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1003  assert(DstTy->isFloatingPointTy() && "Invalid SIToFP instruction");
1004
1005  if (DstTy->getTypeID() == Type::FloatTyID)
1006    Dest.FloatVal = APIntOps::RoundSignedAPIntToFloat(Src.IntVal);
1007  else
1008    Dest.DoubleVal = APIntOps::RoundSignedAPIntToDouble(Src.IntVal);
1009  return Dest;
1010
1011}
1012
1013GenericValue Interpreter::executePtrToIntInst(Value *SrcVal, Type *DstTy,
1014                                              ExecutionContext &SF) {
1015  uint32_t DBitWidth = cast<IntegerType>(DstTy)->getBitWidth();
1016  GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1017  assert(SrcVal->getType()->isPointerTy() && "Invalid PtrToInt instruction");
1018
1019  Dest.IntVal = APInt(DBitWidth, (intptr_t) Src.PointerVal);
1020  return Dest;
1021}
1022
1023GenericValue Interpreter::executeIntToPtrInst(Value *SrcVal, Type *DstTy,
1024                                              ExecutionContext &SF) {
1025  GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1026  assert(DstTy->isPointerTy() && "Invalid PtrToInt instruction");
1027
1028  uint32_t PtrSize = TD.getPointerSizeInBits();
1029  if (PtrSize != Src.IntVal.getBitWidth())
1030    Src.IntVal = Src.IntVal.zextOrTrunc(PtrSize);
1031
1032  Dest.PointerVal = PointerTy(intptr_t(Src.IntVal.getZExtValue()));
1033  return Dest;
1034}
1035
1036GenericValue Interpreter::executeBitCastInst(Value *SrcVal, Type *DstTy,
1037                                             ExecutionContext &SF) {
1038
1039  Type *SrcTy = SrcVal->getType();
1040  GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1041  if (DstTy->isPointerTy()) {
1042    assert(SrcTy->isPointerTy() && "Invalid BitCast");
1043    Dest.PointerVal = Src.PointerVal;
1044  } else if (DstTy->isIntegerTy()) {
1045    if (SrcTy->isFloatTy()) {
1046      Dest.IntVal = APInt::floatToBits(Src.FloatVal);
1047    } else if (SrcTy->isDoubleTy()) {
1048      Dest.IntVal = APInt::doubleToBits(Src.DoubleVal);
1049    } else if (SrcTy->isIntegerTy()) {
1050      Dest.IntVal = Src.IntVal;
1051    } else
1052      llvm_unreachable("Invalid BitCast");
1053  } else if (DstTy->isFloatTy()) {
1054    if (SrcTy->isIntegerTy())
1055      Dest.FloatVal = Src.IntVal.bitsToFloat();
1056    else
1057      Dest.FloatVal = Src.FloatVal;
1058  } else if (DstTy->isDoubleTy()) {
1059    if (SrcTy->isIntegerTy())
1060      Dest.DoubleVal = Src.IntVal.bitsToDouble();
1061    else
1062      Dest.DoubleVal = Src.DoubleVal;
1063  } else
1064    llvm_unreachable("Invalid Bitcast");
1065
1066  return Dest;
1067}
1068
1069void Interpreter::visitTruncInst(TruncInst &I) {
1070  ExecutionContext &SF = ECStack.back();
1071  SetValue(&I, executeTruncInst(I.getOperand(0), I.getType(), SF), SF);
1072}
1073
1074void Interpreter::visitSExtInst(SExtInst &I) {
1075  ExecutionContext &SF = ECStack.back();
1076  SetValue(&I, executeSExtInst(I.getOperand(0), I.getType(), SF), SF);
1077}
1078
1079void Interpreter::visitZExtInst(ZExtInst &I) {
1080  ExecutionContext &SF = ECStack.back();
1081  SetValue(&I, executeZExtInst(I.getOperand(0), I.getType(), SF), SF);
1082}
1083
1084void Interpreter::visitFPTruncInst(FPTruncInst &I) {
1085  ExecutionContext &SF = ECStack.back();
1086  SetValue(&I, executeFPTruncInst(I.getOperand(0), I.getType(), SF), SF);
1087}
1088
1089void Interpreter::visitFPExtInst(FPExtInst &I) {
1090  ExecutionContext &SF = ECStack.back();
1091  SetValue(&I, executeFPExtInst(I.getOperand(0), I.getType(), SF), SF);
1092}
1093
1094void Interpreter::visitUIToFPInst(UIToFPInst &I) {
1095  ExecutionContext &SF = ECStack.back();
1096  SetValue(&I, executeUIToFPInst(I.getOperand(0), I.getType(), SF), SF);
1097}
1098
1099void Interpreter::visitSIToFPInst(SIToFPInst &I) {
1100  ExecutionContext &SF = ECStack.back();
1101  SetValue(&I, executeSIToFPInst(I.getOperand(0), I.getType(), SF), SF);
1102}
1103
1104void Interpreter::visitFPToUIInst(FPToUIInst &I) {
1105  ExecutionContext &SF = ECStack.back();
1106  SetValue(&I, executeFPToUIInst(I.getOperand(0), I.getType(), SF), SF);
1107}
1108
1109void Interpreter::visitFPToSIInst(FPToSIInst &I) {
1110  ExecutionContext &SF = ECStack.back();
1111  SetValue(&I, executeFPToSIInst(I.getOperand(0), I.getType(), SF), SF);
1112}
1113
1114void Interpreter::visitPtrToIntInst(PtrToIntInst &I) {
1115  ExecutionContext &SF = ECStack.back();
1116  SetValue(&I, executePtrToIntInst(I.getOperand(0), I.getType(), SF), SF);
1117}
1118
1119void Interpreter::visitIntToPtrInst(IntToPtrInst &I) {
1120  ExecutionContext &SF = ECStack.back();
1121  SetValue(&I, executeIntToPtrInst(I.getOperand(0), I.getType(), SF), SF);
1122}
1123
1124void Interpreter::visitBitCastInst(BitCastInst &I) {
1125  ExecutionContext &SF = ECStack.back();
1126  SetValue(&I, executeBitCastInst(I.getOperand(0), I.getType(), SF), SF);
1127}
1128
1129#define IMPLEMENT_VAARG(TY) \
1130   case Type::TY##TyID: Dest.TY##Val = Src.TY##Val; break
1131
1132void Interpreter::visitVAArgInst(VAArgInst &I) {
1133  ExecutionContext &SF = ECStack.back();
1134
1135  // Get the incoming valist parameter.  LLI treats the valist as a
1136  // (ec-stack-depth var-arg-index) pair.
1137  GenericValue VAList = getOperandValue(I.getOperand(0), SF);
1138  GenericValue Dest;
1139  GenericValue Src = ECStack[VAList.UIntPairVal.first]
1140                      .VarArgs[VAList.UIntPairVal.second];
1141  Type *Ty = I.getType();
1142  switch (Ty->getTypeID()) {
1143    case Type::IntegerTyID: Dest.IntVal = Src.IntVal;
1144    IMPLEMENT_VAARG(Pointer);
1145    IMPLEMENT_VAARG(Float);
1146    IMPLEMENT_VAARG(Double);
1147  default:
1148    dbgs() << "Unhandled dest type for vaarg instruction: " << *Ty << "\n";
1149    llvm_unreachable(0);
1150  }
1151
1152  // Set the Value of this Instruction.
1153  SetValue(&I, Dest, SF);
1154
1155  // Move the pointer to the next vararg.
1156  ++VAList.UIntPairVal.second;
1157}
1158
1159GenericValue Interpreter::getConstantExprValue (ConstantExpr *CE,
1160                                                ExecutionContext &SF) {
1161  switch (CE->getOpcode()) {
1162  case Instruction::Trunc:
1163      return executeTruncInst(CE->getOperand(0), CE->getType(), SF);
1164  case Instruction::ZExt:
1165      return executeZExtInst(CE->getOperand(0), CE->getType(), SF);
1166  case Instruction::SExt:
1167      return executeSExtInst(CE->getOperand(0), CE->getType(), SF);
1168  case Instruction::FPTrunc:
1169      return executeFPTruncInst(CE->getOperand(0), CE->getType(), SF);
1170  case Instruction::FPExt:
1171      return executeFPExtInst(CE->getOperand(0), CE->getType(), SF);
1172  case Instruction::UIToFP:
1173      return executeUIToFPInst(CE->getOperand(0), CE->getType(), SF);
1174  case Instruction::SIToFP:
1175      return executeSIToFPInst(CE->getOperand(0), CE->getType(), SF);
1176  case Instruction::FPToUI:
1177      return executeFPToUIInst(CE->getOperand(0), CE->getType(), SF);
1178  case Instruction::FPToSI:
1179      return executeFPToSIInst(CE->getOperand(0), CE->getType(), SF);
1180  case Instruction::PtrToInt:
1181      return executePtrToIntInst(CE->getOperand(0), CE->getType(), SF);
1182  case Instruction::IntToPtr:
1183      return executeIntToPtrInst(CE->getOperand(0), CE->getType(), SF);
1184  case Instruction::BitCast:
1185      return executeBitCastInst(CE->getOperand(0), CE->getType(), SF);
1186  case Instruction::GetElementPtr:
1187    return executeGEPOperation(CE->getOperand(0), gep_type_begin(CE),
1188                               gep_type_end(CE), SF);
1189  case Instruction::FCmp:
1190  case Instruction::ICmp:
1191    return executeCmpInst(CE->getPredicate(),
1192                          getOperandValue(CE->getOperand(0), SF),
1193                          getOperandValue(CE->getOperand(1), SF),
1194                          CE->getOperand(0)->getType());
1195  case Instruction::Select:
1196    return executeSelectInst(getOperandValue(CE->getOperand(0), SF),
1197                             getOperandValue(CE->getOperand(1), SF),
1198                             getOperandValue(CE->getOperand(2), SF));
1199  default :
1200    break;
1201  }
1202
1203  // The cases below here require a GenericValue parameter for the result
1204  // so we initialize one, compute it and then return it.
1205  GenericValue Op0 = getOperandValue(CE->getOperand(0), SF);
1206  GenericValue Op1 = getOperandValue(CE->getOperand(1), SF);
1207  GenericValue Dest;
1208  Type * Ty = CE->getOperand(0)->getType();
1209  switch (CE->getOpcode()) {
1210  case Instruction::Add:  Dest.IntVal = Op0.IntVal + Op1.IntVal; break;
1211  case Instruction::Sub:  Dest.IntVal = Op0.IntVal - Op1.IntVal; break;
1212  case Instruction::Mul:  Dest.IntVal = Op0.IntVal * Op1.IntVal; break;
1213  case Instruction::FAdd: executeFAddInst(Dest, Op0, Op1, Ty); break;
1214  case Instruction::FSub: executeFSubInst(Dest, Op0, Op1, Ty); break;
1215  case Instruction::FMul: executeFMulInst(Dest, Op0, Op1, Ty); break;
1216  case Instruction::FDiv: executeFDivInst(Dest, Op0, Op1, Ty); break;
1217  case Instruction::FRem: executeFRemInst(Dest, Op0, Op1, Ty); break;
1218  case Instruction::SDiv: Dest.IntVal = Op0.IntVal.sdiv(Op1.IntVal); break;
1219  case Instruction::UDiv: Dest.IntVal = Op0.IntVal.udiv(Op1.IntVal); break;
1220  case Instruction::URem: Dest.IntVal = Op0.IntVal.urem(Op1.IntVal); break;
1221  case Instruction::SRem: Dest.IntVal = Op0.IntVal.srem(Op1.IntVal); break;
1222  case Instruction::And:  Dest.IntVal = Op0.IntVal & Op1.IntVal; break;
1223  case Instruction::Or:   Dest.IntVal = Op0.IntVal | Op1.IntVal; break;
1224  case Instruction::Xor:  Dest.IntVal = Op0.IntVal ^ Op1.IntVal; break;
1225  case Instruction::Shl:
1226    Dest.IntVal = Op0.IntVal.shl(Op1.IntVal.getZExtValue());
1227    break;
1228  case Instruction::LShr:
1229    Dest.IntVal = Op0.IntVal.lshr(Op1.IntVal.getZExtValue());
1230    break;
1231  case Instruction::AShr:
1232    Dest.IntVal = Op0.IntVal.ashr(Op1.IntVal.getZExtValue());
1233    break;
1234  default:
1235    dbgs() << "Unhandled ConstantExpr: " << *CE << "\n";
1236    llvm_unreachable("Unhandled ConstantExpr");
1237  }
1238  return Dest;
1239}
1240
1241GenericValue Interpreter::getOperandValue(Value *V, ExecutionContext &SF) {
1242  if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
1243    return getConstantExprValue(CE, SF);
1244  } else if (Constant *CPV = dyn_cast<Constant>(V)) {
1245    return getConstantValue(CPV);
1246  } else if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
1247    return PTOGV(getPointerToGlobal(GV));
1248  } else {
1249    return SF.Values[V];
1250  }
1251}
1252
1253//===----------------------------------------------------------------------===//
1254//                        Dispatch and Execution Code
1255//===----------------------------------------------------------------------===//
1256
1257//===----------------------------------------------------------------------===//
1258// callFunction - Execute the specified function...
1259//
1260void Interpreter::callFunction(Function *F,
1261                               const std::vector<GenericValue> &ArgVals) {
1262  assert((ECStack.empty() || ECStack.back().Caller.getInstruction() == 0 ||
1263          ECStack.back().Caller.arg_size() == ArgVals.size()) &&
1264         "Incorrect number of arguments passed into function call!");
1265  // Make a new stack frame... and fill it in.
1266  ECStack.push_back(ExecutionContext());
1267  ExecutionContext &StackFrame = ECStack.back();
1268  StackFrame.CurFunction = F;
1269
1270  // Special handling for external functions.
1271  if (F->isDeclaration()) {
1272    GenericValue Result = callExternalFunction (F, ArgVals);
1273    // Simulate a 'ret' instruction of the appropriate type.
1274    popStackAndReturnValueToCaller (F->getReturnType (), Result);
1275    return;
1276  }
1277
1278  // Get pointers to first LLVM BB & Instruction in function.
1279  StackFrame.CurBB     = F->begin();
1280  StackFrame.CurInst   = StackFrame.CurBB->begin();
1281
1282  // Run through the function arguments and initialize their values...
1283  assert((ArgVals.size() == F->arg_size() ||
1284         (ArgVals.size() > F->arg_size() && F->getFunctionType()->isVarArg()))&&
1285         "Invalid number of values passed to function invocation!");
1286
1287  // Handle non-varargs arguments...
1288  unsigned i = 0;
1289  for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end();
1290       AI != E; ++AI, ++i)
1291    SetValue(AI, ArgVals[i], StackFrame);
1292
1293  // Handle varargs arguments...
1294  StackFrame.VarArgs.assign(ArgVals.begin()+i, ArgVals.end());
1295}
1296
1297
1298void Interpreter::run() {
1299  while (!ECStack.empty()) {
1300    // Interpret a single instruction & increment the "PC".
1301    ExecutionContext &SF = ECStack.back();  // Current stack frame
1302    Instruction &I = *SF.CurInst++;         // Increment before execute
1303
1304    // Track the number of dynamic instructions executed.
1305    ++NumDynamicInsts;
1306
1307    DEBUG(dbgs() << "About to interpret: " << I);
1308    visit(I);   // Dispatch to one of the visit* methods...
1309#if 0
1310    // This is not safe, as visiting the instruction could lower it and free I.
1311DEBUG(
1312    if (!isa<CallInst>(I) && !isa<InvokeInst>(I) &&
1313        I.getType() != Type::VoidTy) {
1314      dbgs() << "  --> ";
1315      const GenericValue &Val = SF.Values[&I];
1316      switch (I.getType()->getTypeID()) {
1317      default: llvm_unreachable("Invalid GenericValue Type");
1318      case Type::VoidTyID:    dbgs() << "void"; break;
1319      case Type::FloatTyID:   dbgs() << "float " << Val.FloatVal; break;
1320      case Type::DoubleTyID:  dbgs() << "double " << Val.DoubleVal; break;
1321      case Type::PointerTyID: dbgs() << "void* " << intptr_t(Val.PointerVal);
1322        break;
1323      case Type::IntegerTyID:
1324        dbgs() << "i" << Val.IntVal.getBitWidth() << " "
1325               << Val.IntVal.toStringUnsigned(10)
1326               << " (0x" << Val.IntVal.toStringUnsigned(16) << ")\n";
1327        break;
1328      }
1329    });
1330#endif
1331  }
1332}
1333