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/ADT/APInt.h"
17 #include "llvm/ADT/Statistic.h"
18 #include "llvm/CodeGen/IntrinsicLowering.h"
19 #include "llvm/IR/Constants.h"
20 #include "llvm/IR/DerivedTypes.h"
21 #include "llvm/IR/Instructions.h"
22 #include "llvm/Support/CommandLine.h"
23 #include "llvm/Support/Debug.h"
24 #include "llvm/Support/ErrorHandling.h"
25 #include "llvm/Support/GetElementPtrTypeIterator.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, Type *Ty) {
55   switch (Ty->getTypeID()) {
56     IMPLEMENT_BINARY_OPERATOR(+, Float);
57     IMPLEMENT_BINARY_OPERATOR(+, Double);
58   default:
59     dbgs() << "Unhandled type for FAdd instruction: " << *Ty << "\n";
60     llvm_unreachable(0);
61   }
62 }
63 
64 static void executeFSubInst(GenericValue &Dest, GenericValue Src1,
65                             GenericValue Src2, Type *Ty) {
66   switch (Ty->getTypeID()) {
67     IMPLEMENT_BINARY_OPERATOR(-, Float);
68     IMPLEMENT_BINARY_OPERATOR(-, Double);
69   default:
70     dbgs() << "Unhandled type for FSub instruction: " << *Ty << "\n";
71     llvm_unreachable(0);
72   }
73 }
74 
75 static void executeFMulInst(GenericValue &Dest, GenericValue Src1,
76                             GenericValue Src2, Type *Ty) {
77   switch (Ty->getTypeID()) {
78     IMPLEMENT_BINARY_OPERATOR(*, Float);
79     IMPLEMENT_BINARY_OPERATOR(*, Double);
80   default:
81     dbgs() << "Unhandled type for FMul instruction: " << *Ty << "\n";
82     llvm_unreachable(0);
83   }
84 }
85 
86 static void executeFDivInst(GenericValue &Dest, GenericValue Src1,
87                             GenericValue Src2, Type *Ty) {
88   switch (Ty->getTypeID()) {
89     IMPLEMENT_BINARY_OPERATOR(/, Float);
90     IMPLEMENT_BINARY_OPERATOR(/, Double);
91   default:
92     dbgs() << "Unhandled type for FDiv instruction: " << *Ty << "\n";
93     llvm_unreachable(0);
94   }
95 }
96 
97 static void executeFRemInst(GenericValue &Dest, GenericValue Src1,
98                             GenericValue Src2, 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 #define IMPLEMENT_VECTOR_INTEGER_ICMP(OP, TY)                        \
118   case Type::VectorTyID: {                                           \
119     assert(Src1.AggregateVal.size() == Src2.AggregateVal.size());    \
120     Dest.AggregateVal.resize( Src1.AggregateVal.size() );            \
121     for( uint32_t _i=0;_i<Src1.AggregateVal.size();_i++)             \
122       Dest.AggregateVal[_i].IntVal = APInt(1,                        \
123       Src1.AggregateVal[_i].IntVal.OP(Src2.AggregateVal[_i].IntVal));\
124   } break;
125 
126 // Handle pointers specially because they must be compared with only as much
127 // width as the host has.  We _do not_ want to be comparing 64 bit values when
128 // running on a 32-bit target, otherwise the upper 32 bits might mess up
129 // comparisons if they contain garbage.
130 #define IMPLEMENT_POINTER_ICMP(OP) \
131    case Type::PointerTyID: \
132       Dest.IntVal = APInt(1,(void*)(intptr_t)Src1.PointerVal OP \
133                             (void*)(intptr_t)Src2.PointerVal); \
134       break;
135 
136 static GenericValue executeICMP_EQ(GenericValue Src1, GenericValue Src2,
137                                    Type *Ty) {
138   GenericValue Dest;
139   switch (Ty->getTypeID()) {
140     IMPLEMENT_INTEGER_ICMP(eq,Ty);
141     IMPLEMENT_VECTOR_INTEGER_ICMP(eq,Ty);
142     IMPLEMENT_POINTER_ICMP(==);
143   default:
144     dbgs() << "Unhandled type for ICMP_EQ predicate: " << *Ty << "\n";
145     llvm_unreachable(0);
146   }
147   return Dest;
148 }
149 
150 static GenericValue executeICMP_NE(GenericValue Src1, GenericValue Src2,
151                                    Type *Ty) {
152   GenericValue Dest;
153   switch (Ty->getTypeID()) {
154     IMPLEMENT_INTEGER_ICMP(ne,Ty);
155     IMPLEMENT_VECTOR_INTEGER_ICMP(ne,Ty);
156     IMPLEMENT_POINTER_ICMP(!=);
157   default:
158     dbgs() << "Unhandled type for ICMP_NE predicate: " << *Ty << "\n";
159     llvm_unreachable(0);
160   }
161   return Dest;
162 }
163 
164 static GenericValue executeICMP_ULT(GenericValue Src1, GenericValue Src2,
165                                     Type *Ty) {
166   GenericValue Dest;
167   switch (Ty->getTypeID()) {
168     IMPLEMENT_INTEGER_ICMP(ult,Ty);
169     IMPLEMENT_VECTOR_INTEGER_ICMP(ult,Ty);
170     IMPLEMENT_POINTER_ICMP(<);
171   default:
172     dbgs() << "Unhandled type for ICMP_ULT predicate: " << *Ty << "\n";
173     llvm_unreachable(0);
174   }
175   return Dest;
176 }
177 
178 static GenericValue executeICMP_SLT(GenericValue Src1, GenericValue Src2,
179                                     Type *Ty) {
180   GenericValue Dest;
181   switch (Ty->getTypeID()) {
182     IMPLEMENT_INTEGER_ICMP(slt,Ty);
183     IMPLEMENT_VECTOR_INTEGER_ICMP(slt,Ty);
184     IMPLEMENT_POINTER_ICMP(<);
185   default:
186     dbgs() << "Unhandled type for ICMP_SLT predicate: " << *Ty << "\n";
187     llvm_unreachable(0);
188   }
189   return Dest;
190 }
191 
192 static GenericValue executeICMP_UGT(GenericValue Src1, GenericValue Src2,
193                                     Type *Ty) {
194   GenericValue Dest;
195   switch (Ty->getTypeID()) {
196     IMPLEMENT_INTEGER_ICMP(ugt,Ty);
197     IMPLEMENT_VECTOR_INTEGER_ICMP(ugt,Ty);
198     IMPLEMENT_POINTER_ICMP(>);
199   default:
200     dbgs() << "Unhandled type for ICMP_UGT predicate: " << *Ty << "\n";
201     llvm_unreachable(0);
202   }
203   return Dest;
204 }
205 
206 static GenericValue executeICMP_SGT(GenericValue Src1, GenericValue Src2,
207                                     Type *Ty) {
208   GenericValue Dest;
209   switch (Ty->getTypeID()) {
210     IMPLEMENT_INTEGER_ICMP(sgt,Ty);
211     IMPLEMENT_VECTOR_INTEGER_ICMP(sgt,Ty);
212     IMPLEMENT_POINTER_ICMP(>);
213   default:
214     dbgs() << "Unhandled type for ICMP_SGT predicate: " << *Ty << "\n";
215     llvm_unreachable(0);
216   }
217   return Dest;
218 }
219 
220 static GenericValue executeICMP_ULE(GenericValue Src1, GenericValue Src2,
221                                     Type *Ty) {
222   GenericValue Dest;
223   switch (Ty->getTypeID()) {
224     IMPLEMENT_INTEGER_ICMP(ule,Ty);
225     IMPLEMENT_VECTOR_INTEGER_ICMP(ule,Ty);
226     IMPLEMENT_POINTER_ICMP(<=);
227   default:
228     dbgs() << "Unhandled type for ICMP_ULE predicate: " << *Ty << "\n";
229     llvm_unreachable(0);
230   }
231   return Dest;
232 }
233 
234 static GenericValue executeICMP_SLE(GenericValue Src1, GenericValue Src2,
235                                     Type *Ty) {
236   GenericValue Dest;
237   switch (Ty->getTypeID()) {
238     IMPLEMENT_INTEGER_ICMP(sle,Ty);
239     IMPLEMENT_VECTOR_INTEGER_ICMP(sle,Ty);
240     IMPLEMENT_POINTER_ICMP(<=);
241   default:
242     dbgs() << "Unhandled type for ICMP_SLE predicate: " << *Ty << "\n";
243     llvm_unreachable(0);
244   }
245   return Dest;
246 }
247 
248 static GenericValue executeICMP_UGE(GenericValue Src1, GenericValue Src2,
249                                     Type *Ty) {
250   GenericValue Dest;
251   switch (Ty->getTypeID()) {
252     IMPLEMENT_INTEGER_ICMP(uge,Ty);
253     IMPLEMENT_VECTOR_INTEGER_ICMP(uge,Ty);
254     IMPLEMENT_POINTER_ICMP(>=);
255   default:
256     dbgs() << "Unhandled type for ICMP_UGE predicate: " << *Ty << "\n";
257     llvm_unreachable(0);
258   }
259   return Dest;
260 }
261 
262 static GenericValue executeICMP_SGE(GenericValue Src1, GenericValue Src2,
263                                     Type *Ty) {
264   GenericValue Dest;
265   switch (Ty->getTypeID()) {
266     IMPLEMENT_INTEGER_ICMP(sge,Ty);
267     IMPLEMENT_VECTOR_INTEGER_ICMP(sge,Ty);
268     IMPLEMENT_POINTER_ICMP(>=);
269   default:
270     dbgs() << "Unhandled type for ICMP_SGE predicate: " << *Ty << "\n";
271     llvm_unreachable(0);
272   }
273   return Dest;
274 }
275 
276 void Interpreter::visitICmpInst(ICmpInst &I) {
277   ExecutionContext &SF = ECStack.back();
278   Type *Ty    = I.getOperand(0)->getType();
279   GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
280   GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
281   GenericValue R;   // Result
282 
283   switch (I.getPredicate()) {
284   case ICmpInst::ICMP_EQ:  R = executeICMP_EQ(Src1,  Src2, Ty); break;
285   case ICmpInst::ICMP_NE:  R = executeICMP_NE(Src1,  Src2, Ty); break;
286   case ICmpInst::ICMP_ULT: R = executeICMP_ULT(Src1, Src2, Ty); break;
287   case ICmpInst::ICMP_SLT: R = executeICMP_SLT(Src1, Src2, Ty); break;
288   case ICmpInst::ICMP_UGT: R = executeICMP_UGT(Src1, Src2, Ty); break;
289   case ICmpInst::ICMP_SGT: R = executeICMP_SGT(Src1, Src2, Ty); break;
290   case ICmpInst::ICMP_ULE: R = executeICMP_ULE(Src1, Src2, Ty); break;
291   case ICmpInst::ICMP_SLE: R = executeICMP_SLE(Src1, Src2, Ty); break;
292   case ICmpInst::ICMP_UGE: R = executeICMP_UGE(Src1, Src2, Ty); break;
293   case ICmpInst::ICMP_SGE: R = executeICMP_SGE(Src1, Src2, Ty); break;
294   default:
295     dbgs() << "Don't know how to handle this ICmp predicate!\n-->" << I;
296     llvm_unreachable(0);
297   }
298 
299   SetValue(&I, R, SF);
300 }
301 
302 #define IMPLEMENT_FCMP(OP, TY) \
303    case Type::TY##TyID: \
304      Dest.IntVal = APInt(1,Src1.TY##Val OP Src2.TY##Val); \
305      break
306 
307 #define IMPLEMENT_VECTOR_FCMP_T(OP, TY)                             \
308   assert(Src1.AggregateVal.size() == Src2.AggregateVal.size());     \
309   Dest.AggregateVal.resize( Src1.AggregateVal.size() );             \
310   for( uint32_t _i=0;_i<Src1.AggregateVal.size();_i++)              \
311     Dest.AggregateVal[_i].IntVal = APInt(1,                         \
312     Src1.AggregateVal[_i].TY##Val OP Src2.AggregateVal[_i].TY##Val);\
313   break;
314 
315 #define IMPLEMENT_VECTOR_FCMP(OP)                                   \
316   case Type::VectorTyID:                                            \
317     if(dyn_cast<VectorType>(Ty)->getElementType()->isFloatTy()) {   \
318       IMPLEMENT_VECTOR_FCMP_T(OP, Float);                           \
319     } else {                                                        \
320         IMPLEMENT_VECTOR_FCMP_T(OP, Double);                        \
321     }
322 
323 static GenericValue executeFCMP_OEQ(GenericValue Src1, GenericValue Src2,
324                                    Type *Ty) {
325   GenericValue Dest;
326   switch (Ty->getTypeID()) {
327     IMPLEMENT_FCMP(==, Float);
328     IMPLEMENT_FCMP(==, Double);
329     IMPLEMENT_VECTOR_FCMP(==);
330   default:
331     dbgs() << "Unhandled type for FCmp EQ instruction: " << *Ty << "\n";
332     llvm_unreachable(0);
333   }
334   return Dest;
335 }
336 
337 #define IMPLEMENT_SCALAR_NANS(TY, X,Y)                                      \
338   if (TY->isFloatTy()) {                                                    \
339     if (X.FloatVal != X.FloatVal || Y.FloatVal != Y.FloatVal) {             \
340       Dest.IntVal = APInt(1,false);                                         \
341       return Dest;                                                          \
342     }                                                                       \
343   } else {                                                                  \
344     if (X.DoubleVal != X.DoubleVal || Y.DoubleVal != Y.DoubleVal) {         \
345       Dest.IntVal = APInt(1,false);                                         \
346       return Dest;                                                          \
347     }                                                                       \
348   }
349 
350 #define MASK_VECTOR_NANS_T(X,Y, TZ, FLAG)                                   \
351   assert(X.AggregateVal.size() == Y.AggregateVal.size());                   \
352   Dest.AggregateVal.resize( X.AggregateVal.size() );                        \
353   for( uint32_t _i=0;_i<X.AggregateVal.size();_i++) {                       \
354     if (X.AggregateVal[_i].TZ##Val != X.AggregateVal[_i].TZ##Val ||         \
355         Y.AggregateVal[_i].TZ##Val != Y.AggregateVal[_i].TZ##Val)           \
356       Dest.AggregateVal[_i].IntVal = APInt(1,FLAG);                         \
357     else  {                                                                 \
358       Dest.AggregateVal[_i].IntVal = APInt(1,!FLAG);                        \
359     }                                                                       \
360   }
361 
362 #define MASK_VECTOR_NANS(TY, X,Y, FLAG)                                     \
363   if (TY->isVectorTy()) {                                                   \
364     if (dyn_cast<VectorType>(TY)->getElementType()->isFloatTy()) {          \
365       MASK_VECTOR_NANS_T(X, Y, Float, FLAG)                                 \
366     } else {                                                                \
367       MASK_VECTOR_NANS_T(X, Y, Double, FLAG)                                \
368     }                                                                       \
369   }                                                                         \
370 
371 
372 
373 static GenericValue executeFCMP_ONE(GenericValue Src1, GenericValue Src2,
374                                     Type *Ty)
375 {
376   GenericValue Dest;
377   // if input is scalar value and Src1 or Src2 is NaN return false
378   IMPLEMENT_SCALAR_NANS(Ty, Src1, Src2)
379   // if vector input detect NaNs and fill mask
380   MASK_VECTOR_NANS(Ty, Src1, Src2, false)
381   GenericValue DestMask = Dest;
382   switch (Ty->getTypeID()) {
383     IMPLEMENT_FCMP(!=, Float);
384     IMPLEMENT_FCMP(!=, Double);
385     IMPLEMENT_VECTOR_FCMP(!=);
386     default:
387       dbgs() << "Unhandled type for FCmp NE instruction: " << *Ty << "\n";
388       llvm_unreachable(0);
389   }
390   // in vector case mask out NaN elements
391   if (Ty->isVectorTy())
392     for( size_t _i=0; _i<Src1.AggregateVal.size(); _i++)
393       if (DestMask.AggregateVal[_i].IntVal == false)
394         Dest.AggregateVal[_i].IntVal = APInt(1,false);
395 
396   return Dest;
397 }
398 
399 static GenericValue executeFCMP_OLE(GenericValue Src1, GenericValue Src2,
400                                    Type *Ty) {
401   GenericValue Dest;
402   switch (Ty->getTypeID()) {
403     IMPLEMENT_FCMP(<=, Float);
404     IMPLEMENT_FCMP(<=, Double);
405     IMPLEMENT_VECTOR_FCMP(<=);
406   default:
407     dbgs() << "Unhandled type for FCmp LE instruction: " << *Ty << "\n";
408     llvm_unreachable(0);
409   }
410   return Dest;
411 }
412 
413 static GenericValue executeFCMP_OGE(GenericValue Src1, GenericValue Src2,
414                                    Type *Ty) {
415   GenericValue Dest;
416   switch (Ty->getTypeID()) {
417     IMPLEMENT_FCMP(>=, Float);
418     IMPLEMENT_FCMP(>=, Double);
419     IMPLEMENT_VECTOR_FCMP(>=);
420   default:
421     dbgs() << "Unhandled type for FCmp GE instruction: " << *Ty << "\n";
422     llvm_unreachable(0);
423   }
424   return Dest;
425 }
426 
427 static GenericValue executeFCMP_OLT(GenericValue Src1, GenericValue Src2,
428                                    Type *Ty) {
429   GenericValue Dest;
430   switch (Ty->getTypeID()) {
431     IMPLEMENT_FCMP(<, Float);
432     IMPLEMENT_FCMP(<, Double);
433     IMPLEMENT_VECTOR_FCMP(<);
434   default:
435     dbgs() << "Unhandled type for FCmp LT instruction: " << *Ty << "\n";
436     llvm_unreachable(0);
437   }
438   return Dest;
439 }
440 
441 static GenericValue executeFCMP_OGT(GenericValue Src1, GenericValue Src2,
442                                      Type *Ty) {
443   GenericValue Dest;
444   switch (Ty->getTypeID()) {
445     IMPLEMENT_FCMP(>, Float);
446     IMPLEMENT_FCMP(>, Double);
447     IMPLEMENT_VECTOR_FCMP(>);
448   default:
449     dbgs() << "Unhandled type for FCmp GT instruction: " << *Ty << "\n";
450     llvm_unreachable(0);
451   }
452   return Dest;
453 }
454 
455 #define IMPLEMENT_UNORDERED(TY, X,Y)                                     \
456   if (TY->isFloatTy()) {                                                 \
457     if (X.FloatVal != X.FloatVal || Y.FloatVal != Y.FloatVal) {          \
458       Dest.IntVal = APInt(1,true);                                       \
459       return Dest;                                                       \
460     }                                                                    \
461   } else if (X.DoubleVal != X.DoubleVal || Y.DoubleVal != Y.DoubleVal) { \
462     Dest.IntVal = APInt(1,true);                                         \
463     return Dest;                                                         \
464   }
465 
466 #define IMPLEMENT_VECTOR_UNORDERED(TY, X,Y, _FUNC)                       \
467   if (TY->isVectorTy()) {                                                \
468     GenericValue DestMask = Dest;                                        \
469     Dest = _FUNC(Src1, Src2, Ty);                                        \
470       for( size_t _i=0; _i<Src1.AggregateVal.size(); _i++)               \
471         if (DestMask.AggregateVal[_i].IntVal == true)                    \
472           Dest.AggregateVal[_i].IntVal = APInt(1,true);                  \
473       return Dest;                                                       \
474   }
475 
476 static GenericValue executeFCMP_UEQ(GenericValue Src1, GenericValue Src2,
477                                    Type *Ty) {
478   GenericValue Dest;
479   IMPLEMENT_UNORDERED(Ty, Src1, Src2)
480   MASK_VECTOR_NANS(Ty, Src1, Src2, true)
481   IMPLEMENT_VECTOR_UNORDERED(Ty, Src1, Src2, executeFCMP_OEQ)
482   return executeFCMP_OEQ(Src1, Src2, Ty);
483 
484 }
485 
486 static GenericValue executeFCMP_UNE(GenericValue Src1, GenericValue Src2,
487                                    Type *Ty) {
488   GenericValue Dest;
489   IMPLEMENT_UNORDERED(Ty, Src1, Src2)
490   MASK_VECTOR_NANS(Ty, Src1, Src2, true)
491   IMPLEMENT_VECTOR_UNORDERED(Ty, Src1, Src2, executeFCMP_ONE)
492   return executeFCMP_ONE(Src1, Src2, Ty);
493 }
494 
495 static GenericValue executeFCMP_ULE(GenericValue Src1, GenericValue Src2,
496                                    Type *Ty) {
497   GenericValue Dest;
498   IMPLEMENT_UNORDERED(Ty, Src1, Src2)
499   MASK_VECTOR_NANS(Ty, Src1, Src2, true)
500   IMPLEMENT_VECTOR_UNORDERED(Ty, Src1, Src2, executeFCMP_OLE)
501   return executeFCMP_OLE(Src1, Src2, Ty);
502 }
503 
504 static GenericValue executeFCMP_UGE(GenericValue Src1, GenericValue Src2,
505                                    Type *Ty) {
506   GenericValue Dest;
507   IMPLEMENT_UNORDERED(Ty, Src1, Src2)
508   MASK_VECTOR_NANS(Ty, Src1, Src2, true)
509   IMPLEMENT_VECTOR_UNORDERED(Ty, Src1, Src2, executeFCMP_OGE)
510   return executeFCMP_OGE(Src1, Src2, Ty);
511 }
512 
513 static GenericValue executeFCMP_ULT(GenericValue Src1, GenericValue Src2,
514                                    Type *Ty) {
515   GenericValue Dest;
516   IMPLEMENT_UNORDERED(Ty, Src1, Src2)
517   MASK_VECTOR_NANS(Ty, Src1, Src2, true)
518   IMPLEMENT_VECTOR_UNORDERED(Ty, Src1, Src2, executeFCMP_OLT)
519   return executeFCMP_OLT(Src1, Src2, Ty);
520 }
521 
522 static GenericValue executeFCMP_UGT(GenericValue Src1, GenericValue Src2,
523                                      Type *Ty) {
524   GenericValue Dest;
525   IMPLEMENT_UNORDERED(Ty, Src1, Src2)
526   MASK_VECTOR_NANS(Ty, Src1, Src2, true)
527   IMPLEMENT_VECTOR_UNORDERED(Ty, Src1, Src2, executeFCMP_OGT)
528   return executeFCMP_OGT(Src1, Src2, Ty);
529 }
530 
531 static GenericValue executeFCMP_ORD(GenericValue Src1, GenericValue Src2,
532                                      Type *Ty) {
533   GenericValue Dest;
534   if(Ty->isVectorTy()) {
535     assert(Src1.AggregateVal.size() == Src2.AggregateVal.size());
536     Dest.AggregateVal.resize( Src1.AggregateVal.size() );
537     if(dyn_cast<VectorType>(Ty)->getElementType()->isFloatTy()) {
538       for( size_t _i=0;_i<Src1.AggregateVal.size();_i++)
539         Dest.AggregateVal[_i].IntVal = APInt(1,
540         ( (Src1.AggregateVal[_i].FloatVal ==
541         Src1.AggregateVal[_i].FloatVal) &&
542         (Src2.AggregateVal[_i].FloatVal ==
543         Src2.AggregateVal[_i].FloatVal)));
544     } else {
545       for( size_t _i=0;_i<Src1.AggregateVal.size();_i++)
546         Dest.AggregateVal[_i].IntVal = APInt(1,
547         ( (Src1.AggregateVal[_i].DoubleVal ==
548         Src1.AggregateVal[_i].DoubleVal) &&
549         (Src2.AggregateVal[_i].DoubleVal ==
550         Src2.AggregateVal[_i].DoubleVal)));
551     }
552   } else if (Ty->isFloatTy())
553     Dest.IntVal = APInt(1,(Src1.FloatVal == Src1.FloatVal &&
554                            Src2.FloatVal == Src2.FloatVal));
555   else {
556     Dest.IntVal = APInt(1,(Src1.DoubleVal == Src1.DoubleVal &&
557                            Src2.DoubleVal == Src2.DoubleVal));
558   }
559   return Dest;
560 }
561 
562 static GenericValue executeFCMP_UNO(GenericValue Src1, GenericValue Src2,
563                                      Type *Ty) {
564   GenericValue Dest;
565   if(Ty->isVectorTy()) {
566     assert(Src1.AggregateVal.size() == Src2.AggregateVal.size());
567     Dest.AggregateVal.resize( Src1.AggregateVal.size() );
568     if(dyn_cast<VectorType>(Ty)->getElementType()->isFloatTy()) {
569       for( size_t _i=0;_i<Src1.AggregateVal.size();_i++)
570         Dest.AggregateVal[_i].IntVal = APInt(1,
571         ( (Src1.AggregateVal[_i].FloatVal !=
572            Src1.AggregateVal[_i].FloatVal) ||
573           (Src2.AggregateVal[_i].FloatVal !=
574            Src2.AggregateVal[_i].FloatVal)));
575       } else {
576         for( size_t _i=0;_i<Src1.AggregateVal.size();_i++)
577           Dest.AggregateVal[_i].IntVal = APInt(1,
578           ( (Src1.AggregateVal[_i].DoubleVal !=
579              Src1.AggregateVal[_i].DoubleVal) ||
580             (Src2.AggregateVal[_i].DoubleVal !=
581              Src2.AggregateVal[_i].DoubleVal)));
582       }
583   } else if (Ty->isFloatTy())
584     Dest.IntVal = APInt(1,(Src1.FloatVal != Src1.FloatVal ||
585                            Src2.FloatVal != Src2.FloatVal));
586   else {
587     Dest.IntVal = APInt(1,(Src1.DoubleVal != Src1.DoubleVal ||
588                            Src2.DoubleVal != Src2.DoubleVal));
589   }
590   return Dest;
591 }
592 
593 static GenericValue executeFCMP_BOOL(GenericValue Src1, GenericValue Src2,
594                                     const Type *Ty, const bool val) {
595   GenericValue Dest;
596     if(Ty->isVectorTy()) {
597       assert(Src1.AggregateVal.size() == Src2.AggregateVal.size());
598       Dest.AggregateVal.resize( Src1.AggregateVal.size() );
599       for( size_t _i=0; _i<Src1.AggregateVal.size(); _i++)
600         Dest.AggregateVal[_i].IntVal = APInt(1,val);
601     } else {
602       Dest.IntVal = APInt(1, val);
603     }
604 
605     return Dest;
606 }
607 
608 void Interpreter::visitFCmpInst(FCmpInst &I) {
609   ExecutionContext &SF = ECStack.back();
610   Type *Ty    = I.getOperand(0)->getType();
611   GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
612   GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
613   GenericValue R;   // Result
614 
615   switch (I.getPredicate()) {
616   default:
617     dbgs() << "Don't know how to handle this FCmp predicate!\n-->" << I;
618     llvm_unreachable(0);
619   break;
620   case FCmpInst::FCMP_FALSE: R = executeFCMP_BOOL(Src1, Src2, Ty, false);
621   break;
622   case FCmpInst::FCMP_TRUE:  R = executeFCMP_BOOL(Src1, Src2, Ty, true);
623   break;
624   case FCmpInst::FCMP_ORD:   R = executeFCMP_ORD(Src1, Src2, Ty); break;
625   case FCmpInst::FCMP_UNO:   R = executeFCMP_UNO(Src1, Src2, Ty); break;
626   case FCmpInst::FCMP_UEQ:   R = executeFCMP_UEQ(Src1, Src2, Ty); break;
627   case FCmpInst::FCMP_OEQ:   R = executeFCMP_OEQ(Src1, Src2, Ty); break;
628   case FCmpInst::FCMP_UNE:   R = executeFCMP_UNE(Src1, Src2, Ty); break;
629   case FCmpInst::FCMP_ONE:   R = executeFCMP_ONE(Src1, Src2, Ty); break;
630   case FCmpInst::FCMP_ULT:   R = executeFCMP_ULT(Src1, Src2, Ty); break;
631   case FCmpInst::FCMP_OLT:   R = executeFCMP_OLT(Src1, Src2, Ty); break;
632   case FCmpInst::FCMP_UGT:   R = executeFCMP_UGT(Src1, Src2, Ty); break;
633   case FCmpInst::FCMP_OGT:   R = executeFCMP_OGT(Src1, Src2, Ty); break;
634   case FCmpInst::FCMP_ULE:   R = executeFCMP_ULE(Src1, Src2, Ty); break;
635   case FCmpInst::FCMP_OLE:   R = executeFCMP_OLE(Src1, Src2, Ty); break;
636   case FCmpInst::FCMP_UGE:   R = executeFCMP_UGE(Src1, Src2, Ty); break;
637   case FCmpInst::FCMP_OGE:   R = executeFCMP_OGE(Src1, Src2, Ty); break;
638   }
639 
640   SetValue(&I, R, SF);
641 }
642 
643 static GenericValue executeCmpInst(unsigned predicate, GenericValue Src1,
644                                    GenericValue Src2, Type *Ty) {
645   GenericValue Result;
646   switch (predicate) {
647   case ICmpInst::ICMP_EQ:    return executeICMP_EQ(Src1, Src2, Ty);
648   case ICmpInst::ICMP_NE:    return executeICMP_NE(Src1, Src2, Ty);
649   case ICmpInst::ICMP_UGT:   return executeICMP_UGT(Src1, Src2, Ty);
650   case ICmpInst::ICMP_SGT:   return executeICMP_SGT(Src1, Src2, Ty);
651   case ICmpInst::ICMP_ULT:   return executeICMP_ULT(Src1, Src2, Ty);
652   case ICmpInst::ICMP_SLT:   return executeICMP_SLT(Src1, Src2, Ty);
653   case ICmpInst::ICMP_UGE:   return executeICMP_UGE(Src1, Src2, Ty);
654   case ICmpInst::ICMP_SGE:   return executeICMP_SGE(Src1, Src2, Ty);
655   case ICmpInst::ICMP_ULE:   return executeICMP_ULE(Src1, Src2, Ty);
656   case ICmpInst::ICMP_SLE:   return executeICMP_SLE(Src1, Src2, Ty);
657   case FCmpInst::FCMP_ORD:   return executeFCMP_ORD(Src1, Src2, Ty);
658   case FCmpInst::FCMP_UNO:   return executeFCMP_UNO(Src1, Src2, Ty);
659   case FCmpInst::FCMP_OEQ:   return executeFCMP_OEQ(Src1, Src2, Ty);
660   case FCmpInst::FCMP_UEQ:   return executeFCMP_UEQ(Src1, Src2, Ty);
661   case FCmpInst::FCMP_ONE:   return executeFCMP_ONE(Src1, Src2, Ty);
662   case FCmpInst::FCMP_UNE:   return executeFCMP_UNE(Src1, Src2, Ty);
663   case FCmpInst::FCMP_OLT:   return executeFCMP_OLT(Src1, Src2, Ty);
664   case FCmpInst::FCMP_ULT:   return executeFCMP_ULT(Src1, Src2, Ty);
665   case FCmpInst::FCMP_OGT:   return executeFCMP_OGT(Src1, Src2, Ty);
666   case FCmpInst::FCMP_UGT:   return executeFCMP_UGT(Src1, Src2, Ty);
667   case FCmpInst::FCMP_OLE:   return executeFCMP_OLE(Src1, Src2, Ty);
668   case FCmpInst::FCMP_ULE:   return executeFCMP_ULE(Src1, Src2, Ty);
669   case FCmpInst::FCMP_OGE:   return executeFCMP_OGE(Src1, Src2, Ty);
670   case FCmpInst::FCMP_UGE:   return executeFCMP_UGE(Src1, Src2, Ty);
671   case FCmpInst::FCMP_FALSE: return executeFCMP_BOOL(Src1, Src2, Ty, false);
672   case FCmpInst::FCMP_TRUE:  return executeFCMP_BOOL(Src1, Src2, Ty, true);
673   default:
674     dbgs() << "Unhandled Cmp predicate\n";
675     llvm_unreachable(0);
676   }
677 }
678 
679 void Interpreter::visitBinaryOperator(BinaryOperator &I) {
680   ExecutionContext &SF = ECStack.back();
681   Type *Ty    = I.getOperand(0)->getType();
682   GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
683   GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
684   GenericValue R;   // Result
685 
686   // First process vector operation
687   if (Ty->isVectorTy()) {
688     assert(Src1.AggregateVal.size() == Src2.AggregateVal.size());
689     R.AggregateVal.resize(Src1.AggregateVal.size());
690 
691     // Macros to execute binary operation 'OP' over integer vectors
692 #define INTEGER_VECTOR_OPERATION(OP)                               \
693     for (unsigned i = 0; i < R.AggregateVal.size(); ++i)           \
694       R.AggregateVal[i].IntVal =                                   \
695       Src1.AggregateVal[i].IntVal OP Src2.AggregateVal[i].IntVal;
696 
697     // Additional macros to execute binary operations udiv/sdiv/urem/srem since
698     // they have different notation.
699 #define INTEGER_VECTOR_FUNCTION(OP)                                \
700     for (unsigned i = 0; i < R.AggregateVal.size(); ++i)           \
701       R.AggregateVal[i].IntVal =                                   \
702       Src1.AggregateVal[i].IntVal.OP(Src2.AggregateVal[i].IntVal);
703 
704     // Macros to execute binary operation 'OP' over floating point type TY
705     // (float or double) vectors
706 #define FLOAT_VECTOR_FUNCTION(OP, TY)                               \
707       for (unsigned i = 0; i < R.AggregateVal.size(); ++i)          \
708         R.AggregateVal[i].TY =                                      \
709         Src1.AggregateVal[i].TY OP Src2.AggregateVal[i].TY;
710 
711     // Macros to choose appropriate TY: float or double and run operation
712     // execution
713 #define FLOAT_VECTOR_OP(OP) {                                         \
714   if (dyn_cast<VectorType>(Ty)->getElementType()->isFloatTy())        \
715     FLOAT_VECTOR_FUNCTION(OP, FloatVal)                               \
716   else {                                                              \
717     if (dyn_cast<VectorType>(Ty)->getElementType()->isDoubleTy())     \
718       FLOAT_VECTOR_FUNCTION(OP, DoubleVal)                            \
719     else {                                                            \
720       dbgs() << "Unhandled type for OP instruction: " << *Ty << "\n"; \
721       llvm_unreachable(0);                                            \
722     }                                                                 \
723   }                                                                   \
724 }
725 
726     switch(I.getOpcode()){
727     default:
728       dbgs() << "Don't know how to handle this binary operator!\n-->" << I;
729       llvm_unreachable(0);
730       break;
731     case Instruction::Add:   INTEGER_VECTOR_OPERATION(+) break;
732     case Instruction::Sub:   INTEGER_VECTOR_OPERATION(-) break;
733     case Instruction::Mul:   INTEGER_VECTOR_OPERATION(*) break;
734     case Instruction::UDiv:  INTEGER_VECTOR_FUNCTION(udiv) break;
735     case Instruction::SDiv:  INTEGER_VECTOR_FUNCTION(sdiv) break;
736     case Instruction::URem:  INTEGER_VECTOR_FUNCTION(urem) break;
737     case Instruction::SRem:  INTEGER_VECTOR_FUNCTION(srem) break;
738     case Instruction::And:   INTEGER_VECTOR_OPERATION(&) break;
739     case Instruction::Or:    INTEGER_VECTOR_OPERATION(|) break;
740     case Instruction::Xor:   INTEGER_VECTOR_OPERATION(^) break;
741     case Instruction::FAdd:  FLOAT_VECTOR_OP(+) break;
742     case Instruction::FSub:  FLOAT_VECTOR_OP(-) break;
743     case Instruction::FMul:  FLOAT_VECTOR_OP(*) break;
744     case Instruction::FDiv:  FLOAT_VECTOR_OP(/) break;
745     case Instruction::FRem:
746       if (dyn_cast<VectorType>(Ty)->getElementType()->isFloatTy())
747         for (unsigned i = 0; i < R.AggregateVal.size(); ++i)
748           R.AggregateVal[i].FloatVal =
749           fmod(Src1.AggregateVal[i].FloatVal, Src2.AggregateVal[i].FloatVal);
750       else {
751         if (dyn_cast<VectorType>(Ty)->getElementType()->isDoubleTy())
752           for (unsigned i = 0; i < R.AggregateVal.size(); ++i)
753             R.AggregateVal[i].DoubleVal =
754             fmod(Src1.AggregateVal[i].DoubleVal, Src2.AggregateVal[i].DoubleVal);
755         else {
756           dbgs() << "Unhandled type for Rem instruction: " << *Ty << "\n";
757           llvm_unreachable(0);
758         }
759       }
760       break;
761     }
762   } else {
763     switch (I.getOpcode()) {
764     default:
765       dbgs() << "Don't know how to handle this binary operator!\n-->" << I;
766       llvm_unreachable(0);
767       break;
768     case Instruction::Add:   R.IntVal = Src1.IntVal + Src2.IntVal; break;
769     case Instruction::Sub:   R.IntVal = Src1.IntVal - Src2.IntVal; break;
770     case Instruction::Mul:   R.IntVal = Src1.IntVal * Src2.IntVal; break;
771     case Instruction::FAdd:  executeFAddInst(R, Src1, Src2, Ty); break;
772     case Instruction::FSub:  executeFSubInst(R, Src1, Src2, Ty); break;
773     case Instruction::FMul:  executeFMulInst(R, Src1, Src2, Ty); break;
774     case Instruction::FDiv:  executeFDivInst(R, Src1, Src2, Ty); break;
775     case Instruction::FRem:  executeFRemInst(R, Src1, Src2, Ty); break;
776     case Instruction::UDiv:  R.IntVal = Src1.IntVal.udiv(Src2.IntVal); break;
777     case Instruction::SDiv:  R.IntVal = Src1.IntVal.sdiv(Src2.IntVal); break;
778     case Instruction::URem:  R.IntVal = Src1.IntVal.urem(Src2.IntVal); break;
779     case Instruction::SRem:  R.IntVal = Src1.IntVal.srem(Src2.IntVal); break;
780     case Instruction::And:   R.IntVal = Src1.IntVal & Src2.IntVal; break;
781     case Instruction::Or:    R.IntVal = Src1.IntVal | Src2.IntVal; break;
782     case Instruction::Xor:   R.IntVal = Src1.IntVal ^ Src2.IntVal; break;
783     }
784   }
785   SetValue(&I, R, SF);
786 }
787 
788 static GenericValue executeSelectInst(GenericValue Src1, GenericValue Src2,
789                                       GenericValue Src3, const Type *Ty) {
790     GenericValue Dest;
791     if(Ty->isVectorTy()) {
792       assert(Src1.AggregateVal.size() == Src2.AggregateVal.size());
793       assert(Src2.AggregateVal.size() == Src3.AggregateVal.size());
794       Dest.AggregateVal.resize( Src1.AggregateVal.size() );
795       for (size_t i = 0; i < Src1.AggregateVal.size(); ++i)
796         Dest.AggregateVal[i] = (Src1.AggregateVal[i].IntVal == 0) ?
797           Src3.AggregateVal[i] : Src2.AggregateVal[i];
798     } else {
799       Dest = (Src1.IntVal == 0) ? Src3 : Src2;
800     }
801     return Dest;
802 }
803 
804 void Interpreter::visitSelectInst(SelectInst &I) {
805   ExecutionContext &SF = ECStack.back();
806   const Type * Ty = I.getOperand(0)->getType();
807   GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
808   GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
809   GenericValue Src3 = getOperandValue(I.getOperand(2), SF);
810   GenericValue R = executeSelectInst(Src1, Src2, Src3, Ty);
811   SetValue(&I, R, SF);
812 }
813 
814 //===----------------------------------------------------------------------===//
815 //                     Terminator Instruction Implementations
816 //===----------------------------------------------------------------------===//
817 
818 void Interpreter::exitCalled(GenericValue GV) {
819   // runAtExitHandlers() assumes there are no stack frames, but
820   // if exit() was called, then it had a stack frame. Blow away
821   // the stack before interpreting atexit handlers.
822   ECStack.clear();
823   runAtExitHandlers();
824   exit(GV.IntVal.zextOrTrunc(32).getZExtValue());
825 }
826 
827 /// Pop the last stack frame off of ECStack and then copy the result
828 /// back into the result variable if we are not returning void. The
829 /// result variable may be the ExitValue, or the Value of the calling
830 /// CallInst if there was a previous stack frame. This method may
831 /// invalidate any ECStack iterators you have. This method also takes
832 /// care of switching to the normal destination BB, if we are returning
833 /// from an invoke.
834 ///
835 void Interpreter::popStackAndReturnValueToCaller(Type *RetTy,
836                                                  GenericValue Result) {
837   // Pop the current stack frame.
838   ECStack.pop_back();
839 
840   if (ECStack.empty()) {  // Finished main.  Put result into exit code...
841     if (RetTy && !RetTy->isVoidTy()) {          // Nonvoid return type?
842       ExitValue = Result;   // Capture the exit value of the program
843     } else {
844       memset(&ExitValue.Untyped, 0, sizeof(ExitValue.Untyped));
845     }
846   } else {
847     // If we have a previous stack frame, and we have a previous call,
848     // fill in the return value...
849     ExecutionContext &CallingSF = ECStack.back();
850     if (Instruction *I = CallingSF.Caller.getInstruction()) {
851       // Save result...
852       if (!CallingSF.Caller.getType()->isVoidTy())
853         SetValue(I, Result, CallingSF);
854       if (InvokeInst *II = dyn_cast<InvokeInst> (I))
855         SwitchToNewBasicBlock (II->getNormalDest (), CallingSF);
856       CallingSF.Caller = CallSite();          // We returned from the call...
857     }
858   }
859 }
860 
861 void Interpreter::visitReturnInst(ReturnInst &I) {
862   ExecutionContext &SF = ECStack.back();
863   Type *RetTy = Type::getVoidTy(I.getContext());
864   GenericValue Result;
865 
866   // Save away the return value... (if we are not 'ret void')
867   if (I.getNumOperands()) {
868     RetTy  = I.getReturnValue()->getType();
869     Result = getOperandValue(I.getReturnValue(), SF);
870   }
871 
872   popStackAndReturnValueToCaller(RetTy, Result);
873 }
874 
875 void Interpreter::visitUnreachableInst(UnreachableInst &I) {
876   report_fatal_error("Program executed an 'unreachable' instruction!");
877 }
878 
879 void Interpreter::visitBranchInst(BranchInst &I) {
880   ExecutionContext &SF = ECStack.back();
881   BasicBlock *Dest;
882 
883   Dest = I.getSuccessor(0);          // Uncond branches have a fixed dest...
884   if (!I.isUnconditional()) {
885     Value *Cond = I.getCondition();
886     if (getOperandValue(Cond, SF).IntVal == 0) // If false cond...
887       Dest = I.getSuccessor(1);
888   }
889   SwitchToNewBasicBlock(Dest, SF);
890 }
891 
892 void Interpreter::visitSwitchInst(SwitchInst &I) {
893   ExecutionContext &SF = ECStack.back();
894   Value* Cond = I.getCondition();
895   Type *ElTy = Cond->getType();
896   GenericValue CondVal = getOperandValue(Cond, SF);
897 
898   // Check to see if any of the cases match...
899   BasicBlock *Dest = 0;
900   for (SwitchInst::CaseIt i = I.case_begin(), e = I.case_end(); i != e; ++i) {
901     IntegersSubset& Case = i.getCaseValueEx();
902     if (Case.isSingleNumber()) {
903       // FIXME: Currently work with ConstantInt based numbers.
904       const ConstantInt *CI = Case.getSingleNumber(0).toConstantInt();
905       GenericValue Val = getOperandValue(const_cast<ConstantInt*>(CI), SF);
906       if (executeICMP_EQ(Val, CondVal, ElTy).IntVal != 0) {
907         Dest = cast<BasicBlock>(i.getCaseSuccessor());
908         break;
909       }
910     }
911     if (Case.isSingleNumbersOnly()) {
912       for (unsigned n = 0, en = Case.getNumItems(); n != en; ++n) {
913         // FIXME: Currently work with ConstantInt based numbers.
914         const ConstantInt *CI = Case.getSingleNumber(n).toConstantInt();
915         GenericValue Val = getOperandValue(const_cast<ConstantInt*>(CI), SF);
916         if (executeICMP_EQ(Val, CondVal, ElTy).IntVal != 0) {
917           Dest = cast<BasicBlock>(i.getCaseSuccessor());
918           break;
919         }
920       }
921     } else
922       for (unsigned n = 0, en = Case.getNumItems(); n != en; ++n) {
923         IntegersSubset::Range r = Case.getItem(n);
924         // FIXME: Currently work with ConstantInt based numbers.
925         const ConstantInt *LowCI = r.getLow().toConstantInt();
926         const ConstantInt *HighCI = r.getHigh().toConstantInt();
927         GenericValue Low = getOperandValue(const_cast<ConstantInt*>(LowCI), SF);
928         GenericValue High = getOperandValue(const_cast<ConstantInt*>(HighCI), SF);
929         if (executeICMP_ULE(Low, CondVal, ElTy).IntVal != 0 &&
930             executeICMP_ULE(CondVal, High, ElTy).IntVal != 0) {
931           Dest = cast<BasicBlock>(i.getCaseSuccessor());
932           break;
933         }
934       }
935   }
936   if (!Dest) Dest = I.getDefaultDest();   // No cases matched: use default
937   SwitchToNewBasicBlock(Dest, SF);
938 }
939 
940 void Interpreter::visitIndirectBrInst(IndirectBrInst &I) {
941   ExecutionContext &SF = ECStack.back();
942   void *Dest = GVTOP(getOperandValue(I.getAddress(), SF));
943   SwitchToNewBasicBlock((BasicBlock*)Dest, SF);
944 }
945 
946 
947 // SwitchToNewBasicBlock - This method is used to jump to a new basic block.
948 // This function handles the actual updating of block and instruction iterators
949 // as well as execution of all of the PHI nodes in the destination block.
950 //
951 // This method does this because all of the PHI nodes must be executed
952 // atomically, reading their inputs before any of the results are updated.  Not
953 // doing this can cause problems if the PHI nodes depend on other PHI nodes for
954 // their inputs.  If the input PHI node is updated before it is read, incorrect
955 // results can happen.  Thus we use a two phase approach.
956 //
957 void Interpreter::SwitchToNewBasicBlock(BasicBlock *Dest, ExecutionContext &SF){
958   BasicBlock *PrevBB = SF.CurBB;      // Remember where we came from...
959   SF.CurBB   = Dest;                  // Update CurBB to branch destination
960   SF.CurInst = SF.CurBB->begin();     // Update new instruction ptr...
961 
962   if (!isa<PHINode>(SF.CurInst)) return;  // Nothing fancy to do
963 
964   // Loop over all of the PHI nodes in the current block, reading their inputs.
965   std::vector<GenericValue> ResultValues;
966 
967   for (; PHINode *PN = dyn_cast<PHINode>(SF.CurInst); ++SF.CurInst) {
968     // Search for the value corresponding to this previous bb...
969     int i = PN->getBasicBlockIndex(PrevBB);
970     assert(i != -1 && "PHINode doesn't contain entry for predecessor??");
971     Value *IncomingValue = PN->getIncomingValue(i);
972 
973     // Save the incoming value for this PHI node...
974     ResultValues.push_back(getOperandValue(IncomingValue, SF));
975   }
976 
977   // Now loop over all of the PHI nodes setting their values...
978   SF.CurInst = SF.CurBB->begin();
979   for (unsigned i = 0; isa<PHINode>(SF.CurInst); ++SF.CurInst, ++i) {
980     PHINode *PN = cast<PHINode>(SF.CurInst);
981     SetValue(PN, ResultValues[i], SF);
982   }
983 }
984 
985 //===----------------------------------------------------------------------===//
986 //                     Memory Instruction Implementations
987 //===----------------------------------------------------------------------===//
988 
989 void Interpreter::visitAllocaInst(AllocaInst &I) {
990   ExecutionContext &SF = ECStack.back();
991 
992   Type *Ty = I.getType()->getElementType();  // Type to be allocated
993 
994   // Get the number of elements being allocated by the array...
995   unsigned NumElements =
996     getOperandValue(I.getOperand(0), SF).IntVal.getZExtValue();
997 
998   unsigned TypeSize = (size_t)TD.getTypeAllocSize(Ty);
999 
1000   // Avoid malloc-ing zero bytes, use max()...
1001   unsigned MemToAlloc = std::max(1U, NumElements * TypeSize);
1002 
1003   // Allocate enough memory to hold the type...
1004   void *Memory = malloc(MemToAlloc);
1005 
1006   DEBUG(dbgs() << "Allocated Type: " << *Ty << " (" << TypeSize << " bytes) x "
1007                << NumElements << " (Total: " << MemToAlloc << ") at "
1008                << uintptr_t(Memory) << '\n');
1009 
1010   GenericValue Result = PTOGV(Memory);
1011   assert(Result.PointerVal != 0 && "Null pointer returned by malloc!");
1012   SetValue(&I, Result, SF);
1013 
1014   if (I.getOpcode() == Instruction::Alloca)
1015     ECStack.back().Allocas.add(Memory);
1016 }
1017 
1018 // getElementOffset - The workhorse for getelementptr.
1019 //
1020 GenericValue Interpreter::executeGEPOperation(Value *Ptr, gep_type_iterator I,
1021                                               gep_type_iterator E,
1022                                               ExecutionContext &SF) {
1023   assert(Ptr->getType()->isPointerTy() &&
1024          "Cannot getElementOffset of a nonpointer type!");
1025 
1026   uint64_t Total = 0;
1027 
1028   for (; I != E; ++I) {
1029     if (StructType *STy = dyn_cast<StructType>(*I)) {
1030       const StructLayout *SLO = TD.getStructLayout(STy);
1031 
1032       const ConstantInt *CPU = cast<ConstantInt>(I.getOperand());
1033       unsigned Index = unsigned(CPU->getZExtValue());
1034 
1035       Total += SLO->getElementOffset(Index);
1036     } else {
1037       SequentialType *ST = cast<SequentialType>(*I);
1038       // Get the index number for the array... which must be long type...
1039       GenericValue IdxGV = getOperandValue(I.getOperand(), SF);
1040 
1041       int64_t Idx;
1042       unsigned BitWidth =
1043         cast<IntegerType>(I.getOperand()->getType())->getBitWidth();
1044       if (BitWidth == 32)
1045         Idx = (int64_t)(int32_t)IdxGV.IntVal.getZExtValue();
1046       else {
1047         assert(BitWidth == 64 && "Invalid index type for getelementptr");
1048         Idx = (int64_t)IdxGV.IntVal.getZExtValue();
1049       }
1050       Total += TD.getTypeAllocSize(ST->getElementType())*Idx;
1051     }
1052   }
1053 
1054   GenericValue Result;
1055   Result.PointerVal = ((char*)getOperandValue(Ptr, SF).PointerVal) + Total;
1056   DEBUG(dbgs() << "GEP Index " << Total << " bytes.\n");
1057   return Result;
1058 }
1059 
1060 void Interpreter::visitGetElementPtrInst(GetElementPtrInst &I) {
1061   ExecutionContext &SF = ECStack.back();
1062   SetValue(&I, executeGEPOperation(I.getPointerOperand(),
1063                                    gep_type_begin(I), gep_type_end(I), SF), SF);
1064 }
1065 
1066 void Interpreter::visitLoadInst(LoadInst &I) {
1067   ExecutionContext &SF = ECStack.back();
1068   GenericValue SRC = getOperandValue(I.getPointerOperand(), SF);
1069   GenericValue *Ptr = (GenericValue*)GVTOP(SRC);
1070   GenericValue Result;
1071   LoadValueFromMemory(Result, Ptr, I.getType());
1072   SetValue(&I, Result, SF);
1073   if (I.isVolatile() && PrintVolatile)
1074     dbgs() << "Volatile load " << I;
1075 }
1076 
1077 void Interpreter::visitStoreInst(StoreInst &I) {
1078   ExecutionContext &SF = ECStack.back();
1079   GenericValue Val = getOperandValue(I.getOperand(0), SF);
1080   GenericValue SRC = getOperandValue(I.getPointerOperand(), SF);
1081   StoreValueToMemory(Val, (GenericValue *)GVTOP(SRC),
1082                      I.getOperand(0)->getType());
1083   if (I.isVolatile() && PrintVolatile)
1084     dbgs() << "Volatile store: " << I;
1085 }
1086 
1087 //===----------------------------------------------------------------------===//
1088 //                 Miscellaneous Instruction Implementations
1089 //===----------------------------------------------------------------------===//
1090 
1091 void Interpreter::visitCallSite(CallSite CS) {
1092   ExecutionContext &SF = ECStack.back();
1093 
1094   // Check to see if this is an intrinsic function call...
1095   Function *F = CS.getCalledFunction();
1096   if (F && F->isDeclaration())
1097     switch (F->getIntrinsicID()) {
1098     case Intrinsic::not_intrinsic:
1099       break;
1100     case Intrinsic::vastart: { // va_start
1101       GenericValue ArgIndex;
1102       ArgIndex.UIntPairVal.first = ECStack.size() - 1;
1103       ArgIndex.UIntPairVal.second = 0;
1104       SetValue(CS.getInstruction(), ArgIndex, SF);
1105       return;
1106     }
1107     case Intrinsic::vaend:    // va_end is a noop for the interpreter
1108       return;
1109     case Intrinsic::vacopy:   // va_copy: dest = src
1110       SetValue(CS.getInstruction(), getOperandValue(*CS.arg_begin(), SF), SF);
1111       return;
1112     default:
1113       // If it is an unknown intrinsic function, use the intrinsic lowering
1114       // class to transform it into hopefully tasty LLVM code.
1115       //
1116       BasicBlock::iterator me(CS.getInstruction());
1117       BasicBlock *Parent = CS.getInstruction()->getParent();
1118       bool atBegin(Parent->begin() == me);
1119       if (!atBegin)
1120         --me;
1121       IL->LowerIntrinsicCall(cast<CallInst>(CS.getInstruction()));
1122 
1123       // Restore the CurInst pointer to the first instruction newly inserted, if
1124       // any.
1125       if (atBegin) {
1126         SF.CurInst = Parent->begin();
1127       } else {
1128         SF.CurInst = me;
1129         ++SF.CurInst;
1130       }
1131       return;
1132     }
1133 
1134 
1135   SF.Caller = CS;
1136   std::vector<GenericValue> ArgVals;
1137   const unsigned NumArgs = SF.Caller.arg_size();
1138   ArgVals.reserve(NumArgs);
1139   uint16_t pNum = 1;
1140   for (CallSite::arg_iterator i = SF.Caller.arg_begin(),
1141          e = SF.Caller.arg_end(); i != e; ++i, ++pNum) {
1142     Value *V = *i;
1143     ArgVals.push_back(getOperandValue(V, SF));
1144   }
1145 
1146   // To handle indirect calls, we must get the pointer value from the argument
1147   // and treat it as a function pointer.
1148   GenericValue SRC = getOperandValue(SF.Caller.getCalledValue(), SF);
1149   callFunction((Function*)GVTOP(SRC), ArgVals);
1150 }
1151 
1152 // auxilary function for shift operations
1153 static unsigned getShiftAmount(uint64_t orgShiftAmount,
1154                                llvm::APInt valueToShift) {
1155   unsigned valueWidth = valueToShift.getBitWidth();
1156   if (orgShiftAmount < (uint64_t)valueWidth)
1157     return orgShiftAmount;
1158   // according to the llvm documentation, if orgShiftAmount > valueWidth,
1159   // the result is undfeined. but we do shift by this rule:
1160   return (NextPowerOf2(valueWidth-1) - 1) & orgShiftAmount;
1161 }
1162 
1163 
1164 void Interpreter::visitShl(BinaryOperator &I) {
1165   ExecutionContext &SF = ECStack.back();
1166   GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
1167   GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
1168   GenericValue Dest;
1169   const Type *Ty = I.getType();
1170 
1171   if (Ty->isVectorTy()) {
1172     uint32_t src1Size = uint32_t(Src1.AggregateVal.size());
1173     assert(src1Size == Src2.AggregateVal.size());
1174     for (unsigned i = 0; i < src1Size; i++) {
1175       GenericValue Result;
1176       uint64_t shiftAmount = Src2.AggregateVal[i].IntVal.getZExtValue();
1177       llvm::APInt valueToShift = Src1.AggregateVal[i].IntVal;
1178       Result.IntVal = valueToShift.shl(getShiftAmount(shiftAmount, valueToShift));
1179       Dest.AggregateVal.push_back(Result);
1180     }
1181   } else {
1182     // scalar
1183     uint64_t shiftAmount = Src2.IntVal.getZExtValue();
1184     llvm::APInt valueToShift = Src1.IntVal;
1185     Dest.IntVal = valueToShift.shl(getShiftAmount(shiftAmount, valueToShift));
1186   }
1187 
1188   SetValue(&I, Dest, SF);
1189 }
1190 
1191 void Interpreter::visitLShr(BinaryOperator &I) {
1192   ExecutionContext &SF = ECStack.back();
1193   GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
1194   GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
1195   GenericValue Dest;
1196   const Type *Ty = I.getType();
1197 
1198   if (Ty->isVectorTy()) {
1199     uint32_t src1Size = uint32_t(Src1.AggregateVal.size());
1200     assert(src1Size == Src2.AggregateVal.size());
1201     for (unsigned i = 0; i < src1Size; i++) {
1202       GenericValue Result;
1203       uint64_t shiftAmount = Src2.AggregateVal[i].IntVal.getZExtValue();
1204       llvm::APInt valueToShift = Src1.AggregateVal[i].IntVal;
1205       Result.IntVal = valueToShift.lshr(getShiftAmount(shiftAmount, valueToShift));
1206       Dest.AggregateVal.push_back(Result);
1207     }
1208   } else {
1209     // scalar
1210     uint64_t shiftAmount = Src2.IntVal.getZExtValue();
1211     llvm::APInt valueToShift = Src1.IntVal;
1212     Dest.IntVal = valueToShift.lshr(getShiftAmount(shiftAmount, valueToShift));
1213   }
1214 
1215   SetValue(&I, Dest, SF);
1216 }
1217 
1218 void Interpreter::visitAShr(BinaryOperator &I) {
1219   ExecutionContext &SF = ECStack.back();
1220   GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
1221   GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
1222   GenericValue Dest;
1223   const Type *Ty = I.getType();
1224 
1225   if (Ty->isVectorTy()) {
1226     size_t src1Size = Src1.AggregateVal.size();
1227     assert(src1Size == Src2.AggregateVal.size());
1228     for (unsigned i = 0; i < src1Size; i++) {
1229       GenericValue Result;
1230       uint64_t shiftAmount = Src2.AggregateVal[i].IntVal.getZExtValue();
1231       llvm::APInt valueToShift = Src1.AggregateVal[i].IntVal;
1232       Result.IntVal = valueToShift.ashr(getShiftAmount(shiftAmount, valueToShift));
1233       Dest.AggregateVal.push_back(Result);
1234     }
1235   } else {
1236     // scalar
1237     uint64_t shiftAmount = Src2.IntVal.getZExtValue();
1238     llvm::APInt valueToShift = Src1.IntVal;
1239     Dest.IntVal = valueToShift.ashr(getShiftAmount(shiftAmount, valueToShift));
1240   }
1241 
1242   SetValue(&I, Dest, SF);
1243 }
1244 
1245 GenericValue Interpreter::executeTruncInst(Value *SrcVal, Type *DstTy,
1246                                            ExecutionContext &SF) {
1247   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1248   Type *SrcTy = SrcVal->getType();
1249   if (SrcTy->isVectorTy()) {
1250     Type *DstVecTy = DstTy->getScalarType();
1251     unsigned DBitWidth = cast<IntegerType>(DstVecTy)->getBitWidth();
1252     unsigned NumElts = Src.AggregateVal.size();
1253     // the sizes of src and dst vectors must be equal
1254     Dest.AggregateVal.resize(NumElts);
1255     for (unsigned i = 0; i < NumElts; i++)
1256       Dest.AggregateVal[i].IntVal = Src.AggregateVal[i].IntVal.trunc(DBitWidth);
1257   } else {
1258     IntegerType *DITy = cast<IntegerType>(DstTy);
1259     unsigned DBitWidth = DITy->getBitWidth();
1260     Dest.IntVal = Src.IntVal.trunc(DBitWidth);
1261   }
1262   return Dest;
1263 }
1264 
1265 GenericValue Interpreter::executeSExtInst(Value *SrcVal, Type *DstTy,
1266                                           ExecutionContext &SF) {
1267   const Type *SrcTy = SrcVal->getType();
1268   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1269   if (SrcTy->isVectorTy()) {
1270     const Type *DstVecTy = DstTy->getScalarType();
1271     unsigned DBitWidth = cast<IntegerType>(DstVecTy)->getBitWidth();
1272     unsigned size = Src.AggregateVal.size();
1273     // the sizes of src and dst vectors must be equal.
1274     Dest.AggregateVal.resize(size);
1275     for (unsigned i = 0; i < size; i++)
1276       Dest.AggregateVal[i].IntVal = Src.AggregateVal[i].IntVal.sext(DBitWidth);
1277   } else {
1278     const IntegerType *DITy = cast<IntegerType>(DstTy);
1279     unsigned DBitWidth = DITy->getBitWidth();
1280     Dest.IntVal = Src.IntVal.sext(DBitWidth);
1281   }
1282   return Dest;
1283 }
1284 
1285 GenericValue Interpreter::executeZExtInst(Value *SrcVal, Type *DstTy,
1286                                           ExecutionContext &SF) {
1287   const Type *SrcTy = SrcVal->getType();
1288   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1289   if (SrcTy->isVectorTy()) {
1290     const Type *DstVecTy = DstTy->getScalarType();
1291     unsigned DBitWidth = cast<IntegerType>(DstVecTy)->getBitWidth();
1292 
1293     unsigned size = Src.AggregateVal.size();
1294     // the sizes of src and dst vectors must be equal.
1295     Dest.AggregateVal.resize(size);
1296     for (unsigned i = 0; i < size; i++)
1297       Dest.AggregateVal[i].IntVal = Src.AggregateVal[i].IntVal.zext(DBitWidth);
1298   } else {
1299     const IntegerType *DITy = cast<IntegerType>(DstTy);
1300     unsigned DBitWidth = DITy->getBitWidth();
1301     Dest.IntVal = Src.IntVal.zext(DBitWidth);
1302   }
1303   return Dest;
1304 }
1305 
1306 GenericValue Interpreter::executeFPTruncInst(Value *SrcVal, Type *DstTy,
1307                                              ExecutionContext &SF) {
1308   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1309 
1310   if (SrcVal->getType()->getTypeID() == Type::VectorTyID) {
1311     assert(SrcVal->getType()->getScalarType()->isDoubleTy() &&
1312            DstTy->getScalarType()->isFloatTy() &&
1313            "Invalid FPTrunc instruction");
1314 
1315     unsigned size = Src.AggregateVal.size();
1316     // the sizes of src and dst vectors must be equal.
1317     Dest.AggregateVal.resize(size);
1318     for (unsigned i = 0; i < size; i++)
1319       Dest.AggregateVal[i].FloatVal = (float)Src.AggregateVal[i].DoubleVal;
1320   } else {
1321     assert(SrcVal->getType()->isDoubleTy() && DstTy->isFloatTy() &&
1322            "Invalid FPTrunc instruction");
1323     Dest.FloatVal = (float)Src.DoubleVal;
1324   }
1325 
1326   return Dest;
1327 }
1328 
1329 GenericValue Interpreter::executeFPExtInst(Value *SrcVal, Type *DstTy,
1330                                            ExecutionContext &SF) {
1331   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1332 
1333   if (SrcVal->getType()->getTypeID() == Type::VectorTyID) {
1334     assert(SrcVal->getType()->getScalarType()->isFloatTy() &&
1335            DstTy->getScalarType()->isDoubleTy() && "Invalid FPExt instruction");
1336 
1337     unsigned size = Src.AggregateVal.size();
1338     // the sizes of src and dst vectors must be equal.
1339     Dest.AggregateVal.resize(size);
1340     for (unsigned i = 0; i < size; i++)
1341       Dest.AggregateVal[i].DoubleVal = (double)Src.AggregateVal[i].FloatVal;
1342   } else {
1343     assert(SrcVal->getType()->isFloatTy() && DstTy->isDoubleTy() &&
1344            "Invalid FPExt instruction");
1345     Dest.DoubleVal = (double)Src.FloatVal;
1346   }
1347 
1348   return Dest;
1349 }
1350 
1351 GenericValue Interpreter::executeFPToUIInst(Value *SrcVal, Type *DstTy,
1352                                             ExecutionContext &SF) {
1353   Type *SrcTy = SrcVal->getType();
1354   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1355 
1356   if (SrcTy->getTypeID() == Type::VectorTyID) {
1357     const Type *DstVecTy = DstTy->getScalarType();
1358     const Type *SrcVecTy = SrcTy->getScalarType();
1359     uint32_t DBitWidth = cast<IntegerType>(DstVecTy)->getBitWidth();
1360     unsigned size = Src.AggregateVal.size();
1361     // the sizes of src and dst vectors must be equal.
1362     Dest.AggregateVal.resize(size);
1363 
1364     if (SrcVecTy->getTypeID() == Type::FloatTyID) {
1365       assert(SrcVecTy->isFloatingPointTy() && "Invalid FPToUI instruction");
1366       for (unsigned i = 0; i < size; i++)
1367         Dest.AggregateVal[i].IntVal = APIntOps::RoundFloatToAPInt(
1368             Src.AggregateVal[i].FloatVal, DBitWidth);
1369     } else {
1370       for (unsigned i = 0; i < size; i++)
1371         Dest.AggregateVal[i].IntVal = APIntOps::RoundDoubleToAPInt(
1372             Src.AggregateVal[i].DoubleVal, DBitWidth);
1373     }
1374   } else {
1375     // scalar
1376     uint32_t DBitWidth = cast<IntegerType>(DstTy)->getBitWidth();
1377     assert(SrcTy->isFloatingPointTy() && "Invalid FPToUI instruction");
1378 
1379     if (SrcTy->getTypeID() == Type::FloatTyID)
1380       Dest.IntVal = APIntOps::RoundFloatToAPInt(Src.FloatVal, DBitWidth);
1381     else {
1382       Dest.IntVal = APIntOps::RoundDoubleToAPInt(Src.DoubleVal, DBitWidth);
1383     }
1384   }
1385 
1386   return Dest;
1387 }
1388 
1389 GenericValue Interpreter::executeFPToSIInst(Value *SrcVal, Type *DstTy,
1390                                             ExecutionContext &SF) {
1391   Type *SrcTy = SrcVal->getType();
1392   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1393 
1394   if (SrcTy->getTypeID() == Type::VectorTyID) {
1395     const Type *DstVecTy = DstTy->getScalarType();
1396     const Type *SrcVecTy = SrcTy->getScalarType();
1397     uint32_t DBitWidth = cast<IntegerType>(DstVecTy)->getBitWidth();
1398     unsigned size = Src.AggregateVal.size();
1399     // the sizes of src and dst vectors must be equal
1400     Dest.AggregateVal.resize(size);
1401 
1402     if (SrcVecTy->getTypeID() == Type::FloatTyID) {
1403       assert(SrcVecTy->isFloatingPointTy() && "Invalid FPToSI instruction");
1404       for (unsigned i = 0; i < size; i++)
1405         Dest.AggregateVal[i].IntVal = APIntOps::RoundFloatToAPInt(
1406             Src.AggregateVal[i].FloatVal, DBitWidth);
1407     } else {
1408       for (unsigned i = 0; i < size; i++)
1409         Dest.AggregateVal[i].IntVal = APIntOps::RoundDoubleToAPInt(
1410             Src.AggregateVal[i].DoubleVal, DBitWidth);
1411     }
1412   } else {
1413     // scalar
1414     unsigned DBitWidth = cast<IntegerType>(DstTy)->getBitWidth();
1415     assert(SrcTy->isFloatingPointTy() && "Invalid FPToSI instruction");
1416 
1417     if (SrcTy->getTypeID() == Type::FloatTyID)
1418       Dest.IntVal = APIntOps::RoundFloatToAPInt(Src.FloatVal, DBitWidth);
1419     else {
1420       Dest.IntVal = APIntOps::RoundDoubleToAPInt(Src.DoubleVal, DBitWidth);
1421     }
1422   }
1423   return Dest;
1424 }
1425 
1426 GenericValue Interpreter::executeUIToFPInst(Value *SrcVal, Type *DstTy,
1427                                             ExecutionContext &SF) {
1428   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1429 
1430   if (SrcVal->getType()->getTypeID() == Type::VectorTyID) {
1431     const Type *DstVecTy = DstTy->getScalarType();
1432     unsigned size = Src.AggregateVal.size();
1433     // the sizes of src and dst vectors must be equal
1434     Dest.AggregateVal.resize(size);
1435 
1436     if (DstVecTy->getTypeID() == Type::FloatTyID) {
1437       assert(DstVecTy->isFloatingPointTy() && "Invalid UIToFP instruction");
1438       for (unsigned i = 0; i < size; i++)
1439         Dest.AggregateVal[i].FloatVal =
1440             APIntOps::RoundAPIntToFloat(Src.AggregateVal[i].IntVal);
1441     } else {
1442       for (unsigned i = 0; i < size; i++)
1443         Dest.AggregateVal[i].DoubleVal =
1444             APIntOps::RoundAPIntToDouble(Src.AggregateVal[i].IntVal);
1445     }
1446   } else {
1447     // scalar
1448     assert(DstTy->isFloatingPointTy() && "Invalid UIToFP instruction");
1449     if (DstTy->getTypeID() == Type::FloatTyID)
1450       Dest.FloatVal = APIntOps::RoundAPIntToFloat(Src.IntVal);
1451     else {
1452       Dest.DoubleVal = APIntOps::RoundAPIntToDouble(Src.IntVal);
1453     }
1454   }
1455   return Dest;
1456 }
1457 
1458 GenericValue Interpreter::executeSIToFPInst(Value *SrcVal, Type *DstTy,
1459                                             ExecutionContext &SF) {
1460   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1461 
1462   if (SrcVal->getType()->getTypeID() == Type::VectorTyID) {
1463     const Type *DstVecTy = DstTy->getScalarType();
1464     unsigned size = Src.AggregateVal.size();
1465     // the sizes of src and dst vectors must be equal
1466     Dest.AggregateVal.resize(size);
1467 
1468     if (DstVecTy->getTypeID() == Type::FloatTyID) {
1469       assert(DstVecTy->isFloatingPointTy() && "Invalid SIToFP instruction");
1470       for (unsigned i = 0; i < size; i++)
1471         Dest.AggregateVal[i].FloatVal =
1472             APIntOps::RoundSignedAPIntToFloat(Src.AggregateVal[i].IntVal);
1473     } else {
1474       for (unsigned i = 0; i < size; i++)
1475         Dest.AggregateVal[i].DoubleVal =
1476             APIntOps::RoundSignedAPIntToDouble(Src.AggregateVal[i].IntVal);
1477     }
1478   } else {
1479     // scalar
1480     assert(DstTy->isFloatingPointTy() && "Invalid SIToFP instruction");
1481 
1482     if (DstTy->getTypeID() == Type::FloatTyID)
1483       Dest.FloatVal = APIntOps::RoundSignedAPIntToFloat(Src.IntVal);
1484     else {
1485       Dest.DoubleVal = APIntOps::RoundSignedAPIntToDouble(Src.IntVal);
1486     }
1487   }
1488 
1489   return Dest;
1490 }
1491 
1492 GenericValue Interpreter::executePtrToIntInst(Value *SrcVal, Type *DstTy,
1493                                               ExecutionContext &SF) {
1494   uint32_t DBitWidth = cast<IntegerType>(DstTy)->getBitWidth();
1495   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1496   assert(SrcVal->getType()->isPointerTy() && "Invalid PtrToInt instruction");
1497 
1498   Dest.IntVal = APInt(DBitWidth, (intptr_t) Src.PointerVal);
1499   return Dest;
1500 }
1501 
1502 GenericValue Interpreter::executeIntToPtrInst(Value *SrcVal, Type *DstTy,
1503                                               ExecutionContext &SF) {
1504   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1505   assert(DstTy->isPointerTy() && "Invalid PtrToInt instruction");
1506 
1507   uint32_t PtrSize = TD.getPointerSizeInBits();
1508   if (PtrSize != Src.IntVal.getBitWidth())
1509     Src.IntVal = Src.IntVal.zextOrTrunc(PtrSize);
1510 
1511   Dest.PointerVal = PointerTy(intptr_t(Src.IntVal.getZExtValue()));
1512   return Dest;
1513 }
1514 
1515 GenericValue Interpreter::executeBitCastInst(Value *SrcVal, Type *DstTy,
1516                                              ExecutionContext &SF) {
1517 
1518   // This instruction supports bitwise conversion of vectors to integers and
1519   // to vectors of other types (as long as they have the same size)
1520   Type *SrcTy = SrcVal->getType();
1521   GenericValue Dest, Src = getOperandValue(SrcVal, SF);
1522 
1523   if ((SrcTy->getTypeID() == Type::VectorTyID) ||
1524       (DstTy->getTypeID() == Type::VectorTyID)) {
1525     // vector src bitcast to vector dst or vector src bitcast to scalar dst or
1526     // scalar src bitcast to vector dst
1527     bool isLittleEndian = TD.isLittleEndian();
1528     GenericValue TempDst, TempSrc, SrcVec;
1529     const Type *SrcElemTy;
1530     const Type *DstElemTy;
1531     unsigned SrcBitSize;
1532     unsigned DstBitSize;
1533     unsigned SrcNum;
1534     unsigned DstNum;
1535 
1536     if (SrcTy->getTypeID() == Type::VectorTyID) {
1537       SrcElemTy = SrcTy->getScalarType();
1538       SrcBitSize = SrcTy->getScalarSizeInBits();
1539       SrcNum = Src.AggregateVal.size();
1540       SrcVec = Src;
1541     } else {
1542       // if src is scalar value, make it vector <1 x type>
1543       SrcElemTy = SrcTy;
1544       SrcBitSize = SrcTy->getPrimitiveSizeInBits();
1545       SrcNum = 1;
1546       SrcVec.AggregateVal.push_back(Src);
1547     }
1548 
1549     if (DstTy->getTypeID() == Type::VectorTyID) {
1550       DstElemTy = DstTy->getScalarType();
1551       DstBitSize = DstTy->getScalarSizeInBits();
1552       DstNum = (SrcNum * SrcBitSize) / DstBitSize;
1553     } else {
1554       DstElemTy = DstTy;
1555       DstBitSize = DstTy->getPrimitiveSizeInBits();
1556       DstNum = 1;
1557     }
1558 
1559     if (SrcNum * SrcBitSize != DstNum * DstBitSize)
1560       llvm_unreachable("Invalid BitCast");
1561 
1562     // If src is floating point, cast to integer first.
1563     TempSrc.AggregateVal.resize(SrcNum);
1564     if (SrcElemTy->isFloatTy()) {
1565       for (unsigned i = 0; i < SrcNum; i++)
1566         TempSrc.AggregateVal[i].IntVal =
1567             APInt::floatToBits(SrcVec.AggregateVal[i].FloatVal);
1568 
1569     } else if (SrcElemTy->isDoubleTy()) {
1570       for (unsigned i = 0; i < SrcNum; i++)
1571         TempSrc.AggregateVal[i].IntVal =
1572             APInt::doubleToBits(SrcVec.AggregateVal[i].DoubleVal);
1573     } else if (SrcElemTy->isIntegerTy()) {
1574       for (unsigned i = 0; i < SrcNum; i++)
1575         TempSrc.AggregateVal[i].IntVal = SrcVec.AggregateVal[i].IntVal;
1576     } else {
1577       // Pointers are not allowed as the element type of vector.
1578       llvm_unreachable("Invalid Bitcast");
1579     }
1580 
1581     // now TempSrc is integer type vector
1582     if (DstNum < SrcNum) {
1583       // Example: bitcast <4 x i32> <i32 0, i32 1, i32 2, i32 3> to <2 x i64>
1584       unsigned Ratio = SrcNum / DstNum;
1585       unsigned SrcElt = 0;
1586       for (unsigned i = 0; i < DstNum; i++) {
1587         GenericValue Elt;
1588         Elt.IntVal = 0;
1589         Elt.IntVal = Elt.IntVal.zext(DstBitSize);
1590         unsigned ShiftAmt = isLittleEndian ? 0 : SrcBitSize * (Ratio - 1);
1591         for (unsigned j = 0; j < Ratio; j++) {
1592           APInt Tmp;
1593           Tmp = Tmp.zext(SrcBitSize);
1594           Tmp = TempSrc.AggregateVal[SrcElt++].IntVal;
1595           Tmp = Tmp.zext(DstBitSize);
1596           Tmp = Tmp.shl(ShiftAmt);
1597           ShiftAmt += isLittleEndian ? SrcBitSize : -SrcBitSize;
1598           Elt.IntVal |= Tmp;
1599         }
1600         TempDst.AggregateVal.push_back(Elt);
1601       }
1602     } else {
1603       // Example: bitcast <2 x i64> <i64 0, i64 1> to <4 x i32>
1604       unsigned Ratio = DstNum / SrcNum;
1605       for (unsigned i = 0; i < SrcNum; i++) {
1606         unsigned ShiftAmt = isLittleEndian ? 0 : DstBitSize * (Ratio - 1);
1607         for (unsigned j = 0; j < Ratio; j++) {
1608           GenericValue Elt;
1609           Elt.IntVal = Elt.IntVal.zext(SrcBitSize);
1610           Elt.IntVal = TempSrc.AggregateVal[i].IntVal;
1611           Elt.IntVal = Elt.IntVal.lshr(ShiftAmt);
1612           // it could be DstBitSize == SrcBitSize, so check it
1613           if (DstBitSize < SrcBitSize)
1614             Elt.IntVal = Elt.IntVal.trunc(DstBitSize);
1615           ShiftAmt += isLittleEndian ? DstBitSize : -DstBitSize;
1616           TempDst.AggregateVal.push_back(Elt);
1617         }
1618       }
1619     }
1620 
1621     // convert result from integer to specified type
1622     if (DstTy->getTypeID() == Type::VectorTyID) {
1623       if (DstElemTy->isDoubleTy()) {
1624         Dest.AggregateVal.resize(DstNum);
1625         for (unsigned i = 0; i < DstNum; i++)
1626           Dest.AggregateVal[i].DoubleVal =
1627               TempDst.AggregateVal[i].IntVal.bitsToDouble();
1628       } else if (DstElemTy->isFloatTy()) {
1629         Dest.AggregateVal.resize(DstNum);
1630         for (unsigned i = 0; i < DstNum; i++)
1631           Dest.AggregateVal[i].FloatVal =
1632               TempDst.AggregateVal[i].IntVal.bitsToFloat();
1633       } else {
1634         Dest = TempDst;
1635       }
1636     } else {
1637       if (DstElemTy->isDoubleTy())
1638         Dest.DoubleVal = TempDst.AggregateVal[0].IntVal.bitsToDouble();
1639       else if (DstElemTy->isFloatTy()) {
1640         Dest.FloatVal = TempDst.AggregateVal[0].IntVal.bitsToFloat();
1641       } else {
1642         Dest.IntVal = TempDst.AggregateVal[0].IntVal;
1643       }
1644     }
1645   } else { //  if ((SrcTy->getTypeID() == Type::VectorTyID) ||
1646            //     (DstTy->getTypeID() == Type::VectorTyID))
1647 
1648     // scalar src bitcast to scalar dst
1649     if (DstTy->isPointerTy()) {
1650       assert(SrcTy->isPointerTy() && "Invalid BitCast");
1651       Dest.PointerVal = Src.PointerVal;
1652     } else if (DstTy->isIntegerTy()) {
1653       if (SrcTy->isFloatTy())
1654         Dest.IntVal = APInt::floatToBits(Src.FloatVal);
1655       else if (SrcTy->isDoubleTy()) {
1656         Dest.IntVal = APInt::doubleToBits(Src.DoubleVal);
1657       } else if (SrcTy->isIntegerTy()) {
1658         Dest.IntVal = Src.IntVal;
1659       } else {
1660         llvm_unreachable("Invalid BitCast");
1661       }
1662     } else if (DstTy->isFloatTy()) {
1663       if (SrcTy->isIntegerTy())
1664         Dest.FloatVal = Src.IntVal.bitsToFloat();
1665       else {
1666         Dest.FloatVal = Src.FloatVal;
1667       }
1668     } else if (DstTy->isDoubleTy()) {
1669       if (SrcTy->isIntegerTy())
1670         Dest.DoubleVal = Src.IntVal.bitsToDouble();
1671       else {
1672         Dest.DoubleVal = Src.DoubleVal;
1673       }
1674     } else {
1675       llvm_unreachable("Invalid Bitcast");
1676     }
1677   }
1678 
1679   return Dest;
1680 }
1681 
1682 void Interpreter::visitTruncInst(TruncInst &I) {
1683   ExecutionContext &SF = ECStack.back();
1684   SetValue(&I, executeTruncInst(I.getOperand(0), I.getType(), SF), SF);
1685 }
1686 
1687 void Interpreter::visitSExtInst(SExtInst &I) {
1688   ExecutionContext &SF = ECStack.back();
1689   SetValue(&I, executeSExtInst(I.getOperand(0), I.getType(), SF), SF);
1690 }
1691 
1692 void Interpreter::visitZExtInst(ZExtInst &I) {
1693   ExecutionContext &SF = ECStack.back();
1694   SetValue(&I, executeZExtInst(I.getOperand(0), I.getType(), SF), SF);
1695 }
1696 
1697 void Interpreter::visitFPTruncInst(FPTruncInst &I) {
1698   ExecutionContext &SF = ECStack.back();
1699   SetValue(&I, executeFPTruncInst(I.getOperand(0), I.getType(), SF), SF);
1700 }
1701 
1702 void Interpreter::visitFPExtInst(FPExtInst &I) {
1703   ExecutionContext &SF = ECStack.back();
1704   SetValue(&I, executeFPExtInst(I.getOperand(0), I.getType(), SF), SF);
1705 }
1706 
1707 void Interpreter::visitUIToFPInst(UIToFPInst &I) {
1708   ExecutionContext &SF = ECStack.back();
1709   SetValue(&I, executeUIToFPInst(I.getOperand(0), I.getType(), SF), SF);
1710 }
1711 
1712 void Interpreter::visitSIToFPInst(SIToFPInst &I) {
1713   ExecutionContext &SF = ECStack.back();
1714   SetValue(&I, executeSIToFPInst(I.getOperand(0), I.getType(), SF), SF);
1715 }
1716 
1717 void Interpreter::visitFPToUIInst(FPToUIInst &I) {
1718   ExecutionContext &SF = ECStack.back();
1719   SetValue(&I, executeFPToUIInst(I.getOperand(0), I.getType(), SF), SF);
1720 }
1721 
1722 void Interpreter::visitFPToSIInst(FPToSIInst &I) {
1723   ExecutionContext &SF = ECStack.back();
1724   SetValue(&I, executeFPToSIInst(I.getOperand(0), I.getType(), SF), SF);
1725 }
1726 
1727 void Interpreter::visitPtrToIntInst(PtrToIntInst &I) {
1728   ExecutionContext &SF = ECStack.back();
1729   SetValue(&I, executePtrToIntInst(I.getOperand(0), I.getType(), SF), SF);
1730 }
1731 
1732 void Interpreter::visitIntToPtrInst(IntToPtrInst &I) {
1733   ExecutionContext &SF = ECStack.back();
1734   SetValue(&I, executeIntToPtrInst(I.getOperand(0), I.getType(), SF), SF);
1735 }
1736 
1737 void Interpreter::visitBitCastInst(BitCastInst &I) {
1738   ExecutionContext &SF = ECStack.back();
1739   SetValue(&I, executeBitCastInst(I.getOperand(0), I.getType(), SF), SF);
1740 }
1741 
1742 #define IMPLEMENT_VAARG(TY) \
1743    case Type::TY##TyID: Dest.TY##Val = Src.TY##Val; break
1744 
1745 void Interpreter::visitVAArgInst(VAArgInst &I) {
1746   ExecutionContext &SF = ECStack.back();
1747 
1748   // Get the incoming valist parameter.  LLI treats the valist as a
1749   // (ec-stack-depth var-arg-index) pair.
1750   GenericValue VAList = getOperandValue(I.getOperand(0), SF);
1751   GenericValue Dest;
1752   GenericValue Src = ECStack[VAList.UIntPairVal.first]
1753                       .VarArgs[VAList.UIntPairVal.second];
1754   Type *Ty = I.getType();
1755   switch (Ty->getTypeID()) {
1756   case Type::IntegerTyID:
1757     Dest.IntVal = Src.IntVal;
1758     break;
1759   IMPLEMENT_VAARG(Pointer);
1760   IMPLEMENT_VAARG(Float);
1761   IMPLEMENT_VAARG(Double);
1762   default:
1763     dbgs() << "Unhandled dest type for vaarg instruction: " << *Ty << "\n";
1764     llvm_unreachable(0);
1765   }
1766 
1767   // Set the Value of this Instruction.
1768   SetValue(&I, Dest, SF);
1769 
1770   // Move the pointer to the next vararg.
1771   ++VAList.UIntPairVal.second;
1772 }
1773 
1774 void Interpreter::visitExtractElementInst(ExtractElementInst &I) {
1775   ExecutionContext &SF = ECStack.back();
1776   GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
1777   GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
1778   GenericValue Dest;
1779 
1780   Type *Ty = I.getType();
1781   const unsigned indx = unsigned(Src2.IntVal.getZExtValue());
1782 
1783   if(Src1.AggregateVal.size() > indx) {
1784     switch (Ty->getTypeID()) {
1785     default:
1786       dbgs() << "Unhandled destination type for extractelement instruction: "
1787       << *Ty << "\n";
1788       llvm_unreachable(0);
1789       break;
1790     case Type::IntegerTyID:
1791       Dest.IntVal = Src1.AggregateVal[indx].IntVal;
1792       break;
1793     case Type::FloatTyID:
1794       Dest.FloatVal = Src1.AggregateVal[indx].FloatVal;
1795       break;
1796     case Type::DoubleTyID:
1797       Dest.DoubleVal = Src1.AggregateVal[indx].DoubleVal;
1798       break;
1799     }
1800   } else {
1801     dbgs() << "Invalid index in extractelement instruction\n";
1802   }
1803 
1804   SetValue(&I, Dest, SF);
1805 }
1806 
1807 void Interpreter::visitInsertElementInst(InsertElementInst &I) {
1808   ExecutionContext &SF = ECStack.back();
1809   Type *Ty = I.getType();
1810 
1811   if(!(Ty->isVectorTy()) )
1812     llvm_unreachable("Unhandled dest type for insertelement instruction");
1813 
1814   GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
1815   GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
1816   GenericValue Src3 = getOperandValue(I.getOperand(2), SF);
1817   GenericValue Dest;
1818 
1819   Type *TyContained = Ty->getContainedType(0);
1820 
1821   const unsigned indx = unsigned(Src3.IntVal.getZExtValue());
1822   Dest.AggregateVal = Src1.AggregateVal;
1823 
1824   if(Src1.AggregateVal.size() <= indx)
1825       llvm_unreachable("Invalid index in insertelement instruction");
1826   switch (TyContained->getTypeID()) {
1827     default:
1828       llvm_unreachable("Unhandled dest type for insertelement instruction");
1829     case Type::IntegerTyID:
1830       Dest.AggregateVal[indx].IntVal = Src2.IntVal;
1831       break;
1832     case Type::FloatTyID:
1833       Dest.AggregateVal[indx].FloatVal = Src2.FloatVal;
1834       break;
1835     case Type::DoubleTyID:
1836       Dest.AggregateVal[indx].DoubleVal = Src2.DoubleVal;
1837       break;
1838   }
1839   SetValue(&I, Dest, SF);
1840 }
1841 
1842 void Interpreter::visitShuffleVectorInst(ShuffleVectorInst &I){
1843   ExecutionContext &SF = ECStack.back();
1844 
1845   Type *Ty = I.getType();
1846   if(!(Ty->isVectorTy()))
1847     llvm_unreachable("Unhandled dest type for shufflevector instruction");
1848 
1849   GenericValue Src1 = getOperandValue(I.getOperand(0), SF);
1850   GenericValue Src2 = getOperandValue(I.getOperand(1), SF);
1851   GenericValue Src3 = getOperandValue(I.getOperand(2), SF);
1852   GenericValue Dest;
1853 
1854   // There is no need to check types of src1 and src2, because the compiled
1855   // bytecode can't contain different types for src1 and src2 for a
1856   // shufflevector instruction.
1857 
1858   Type *TyContained = Ty->getContainedType(0);
1859   unsigned src1Size = (unsigned)Src1.AggregateVal.size();
1860   unsigned src2Size = (unsigned)Src2.AggregateVal.size();
1861   unsigned src3Size = (unsigned)Src3.AggregateVal.size();
1862 
1863   Dest.AggregateVal.resize(src3Size);
1864 
1865   switch (TyContained->getTypeID()) {
1866     default:
1867       llvm_unreachable("Unhandled dest type for insertelement instruction");
1868       break;
1869     case Type::IntegerTyID:
1870       for( unsigned i=0; i<src3Size; i++) {
1871         unsigned j = Src3.AggregateVal[i].IntVal.getZExtValue();
1872         if(j < src1Size)
1873           Dest.AggregateVal[i].IntVal = Src1.AggregateVal[j].IntVal;
1874         else if(j < src1Size + src2Size)
1875           Dest.AggregateVal[i].IntVal = Src2.AggregateVal[j-src1Size].IntVal;
1876         else
1877           // The selector may not be greater than sum of lengths of first and
1878           // second operands and llasm should not allow situation like
1879           // %tmp = shufflevector <2 x i32> <i32 3, i32 4>, <2 x i32> undef,
1880           //                      <2 x i32> < i32 0, i32 5 >,
1881           // where i32 5 is invalid, but let it be additional check here:
1882           llvm_unreachable("Invalid mask in shufflevector instruction");
1883       }
1884       break;
1885     case Type::FloatTyID:
1886       for( unsigned i=0; i<src3Size; i++) {
1887         unsigned j = Src3.AggregateVal[i].IntVal.getZExtValue();
1888         if(j < src1Size)
1889           Dest.AggregateVal[i].FloatVal = Src1.AggregateVal[j].FloatVal;
1890         else if(j < src1Size + src2Size)
1891           Dest.AggregateVal[i].FloatVal = Src2.AggregateVal[j-src1Size].FloatVal;
1892         else
1893           llvm_unreachable("Invalid mask in shufflevector instruction");
1894         }
1895       break;
1896     case Type::DoubleTyID:
1897       for( unsigned i=0; i<src3Size; i++) {
1898         unsigned j = Src3.AggregateVal[i].IntVal.getZExtValue();
1899         if(j < src1Size)
1900           Dest.AggregateVal[i].DoubleVal = Src1.AggregateVal[j].DoubleVal;
1901         else if(j < src1Size + src2Size)
1902           Dest.AggregateVal[i].DoubleVal =
1903             Src2.AggregateVal[j-src1Size].DoubleVal;
1904         else
1905           llvm_unreachable("Invalid mask in shufflevector instruction");
1906       }
1907       break;
1908   }
1909   SetValue(&I, Dest, SF);
1910 }
1911 
1912 GenericValue Interpreter::getConstantExprValue (ConstantExpr *CE,
1913                                                 ExecutionContext &SF) {
1914   switch (CE->getOpcode()) {
1915   case Instruction::Trunc:
1916       return executeTruncInst(CE->getOperand(0), CE->getType(), SF);
1917   case Instruction::ZExt:
1918       return executeZExtInst(CE->getOperand(0), CE->getType(), SF);
1919   case Instruction::SExt:
1920       return executeSExtInst(CE->getOperand(0), CE->getType(), SF);
1921   case Instruction::FPTrunc:
1922       return executeFPTruncInst(CE->getOperand(0), CE->getType(), SF);
1923   case Instruction::FPExt:
1924       return executeFPExtInst(CE->getOperand(0), CE->getType(), SF);
1925   case Instruction::UIToFP:
1926       return executeUIToFPInst(CE->getOperand(0), CE->getType(), SF);
1927   case Instruction::SIToFP:
1928       return executeSIToFPInst(CE->getOperand(0), CE->getType(), SF);
1929   case Instruction::FPToUI:
1930       return executeFPToUIInst(CE->getOperand(0), CE->getType(), SF);
1931   case Instruction::FPToSI:
1932       return executeFPToSIInst(CE->getOperand(0), CE->getType(), SF);
1933   case Instruction::PtrToInt:
1934       return executePtrToIntInst(CE->getOperand(0), CE->getType(), SF);
1935   case Instruction::IntToPtr:
1936       return executeIntToPtrInst(CE->getOperand(0), CE->getType(), SF);
1937   case Instruction::BitCast:
1938       return executeBitCastInst(CE->getOperand(0), CE->getType(), SF);
1939   case Instruction::GetElementPtr:
1940     return executeGEPOperation(CE->getOperand(0), gep_type_begin(CE),
1941                                gep_type_end(CE), SF);
1942   case Instruction::FCmp:
1943   case Instruction::ICmp:
1944     return executeCmpInst(CE->getPredicate(),
1945                           getOperandValue(CE->getOperand(0), SF),
1946                           getOperandValue(CE->getOperand(1), SF),
1947                           CE->getOperand(0)->getType());
1948   case Instruction::Select:
1949     return executeSelectInst(getOperandValue(CE->getOperand(0), SF),
1950                              getOperandValue(CE->getOperand(1), SF),
1951                              getOperandValue(CE->getOperand(2), SF),
1952                              CE->getOperand(0)->getType());
1953   default :
1954     break;
1955   }
1956 
1957   // The cases below here require a GenericValue parameter for the result
1958   // so we initialize one, compute it and then return it.
1959   GenericValue Op0 = getOperandValue(CE->getOperand(0), SF);
1960   GenericValue Op1 = getOperandValue(CE->getOperand(1), SF);
1961   GenericValue Dest;
1962   Type * Ty = CE->getOperand(0)->getType();
1963   switch (CE->getOpcode()) {
1964   case Instruction::Add:  Dest.IntVal = Op0.IntVal + Op1.IntVal; break;
1965   case Instruction::Sub:  Dest.IntVal = Op0.IntVal - Op1.IntVal; break;
1966   case Instruction::Mul:  Dest.IntVal = Op0.IntVal * Op1.IntVal; break;
1967   case Instruction::FAdd: executeFAddInst(Dest, Op0, Op1, Ty); break;
1968   case Instruction::FSub: executeFSubInst(Dest, Op0, Op1, Ty); break;
1969   case Instruction::FMul: executeFMulInst(Dest, Op0, Op1, Ty); break;
1970   case Instruction::FDiv: executeFDivInst(Dest, Op0, Op1, Ty); break;
1971   case Instruction::FRem: executeFRemInst(Dest, Op0, Op1, Ty); break;
1972   case Instruction::SDiv: Dest.IntVal = Op0.IntVal.sdiv(Op1.IntVal); break;
1973   case Instruction::UDiv: Dest.IntVal = Op0.IntVal.udiv(Op1.IntVal); break;
1974   case Instruction::URem: Dest.IntVal = Op0.IntVal.urem(Op1.IntVal); break;
1975   case Instruction::SRem: Dest.IntVal = Op0.IntVal.srem(Op1.IntVal); break;
1976   case Instruction::And:  Dest.IntVal = Op0.IntVal & Op1.IntVal; break;
1977   case Instruction::Or:   Dest.IntVal = Op0.IntVal | Op1.IntVal; break;
1978   case Instruction::Xor:  Dest.IntVal = Op0.IntVal ^ Op1.IntVal; break;
1979   case Instruction::Shl:
1980     Dest.IntVal = Op0.IntVal.shl(Op1.IntVal.getZExtValue());
1981     break;
1982   case Instruction::LShr:
1983     Dest.IntVal = Op0.IntVal.lshr(Op1.IntVal.getZExtValue());
1984     break;
1985   case Instruction::AShr:
1986     Dest.IntVal = Op0.IntVal.ashr(Op1.IntVal.getZExtValue());
1987     break;
1988   default:
1989     dbgs() << "Unhandled ConstantExpr: " << *CE << "\n";
1990     llvm_unreachable("Unhandled ConstantExpr");
1991   }
1992   return Dest;
1993 }
1994 
1995 GenericValue Interpreter::getOperandValue(Value *V, ExecutionContext &SF) {
1996   if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
1997     return getConstantExprValue(CE, SF);
1998   } else if (Constant *CPV = dyn_cast<Constant>(V)) {
1999     return getConstantValue(CPV);
2000   } else if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
2001     return PTOGV(getPointerToGlobal(GV));
2002   } else {
2003     return SF.Values[V];
2004   }
2005 }
2006 
2007 //===----------------------------------------------------------------------===//
2008 //                        Dispatch and Execution Code
2009 //===----------------------------------------------------------------------===//
2010 
2011 //===----------------------------------------------------------------------===//
2012 // callFunction - Execute the specified function...
2013 //
2014 void Interpreter::callFunction(Function *F,
2015                                const std::vector<GenericValue> &ArgVals) {
2016   assert((ECStack.empty() || ECStack.back().Caller.getInstruction() == 0 ||
2017           ECStack.back().Caller.arg_size() == ArgVals.size()) &&
2018          "Incorrect number of arguments passed into function call!");
2019   // Make a new stack frame... and fill it in.
2020   ECStack.push_back(ExecutionContext());
2021   ExecutionContext &StackFrame = ECStack.back();
2022   StackFrame.CurFunction = F;
2023 
2024   // Special handling for external functions.
2025   if (F->isDeclaration()) {
2026     GenericValue Result = callExternalFunction (F, ArgVals);
2027     // Simulate a 'ret' instruction of the appropriate type.
2028     popStackAndReturnValueToCaller (F->getReturnType (), Result);
2029     return;
2030   }
2031 
2032   // Get pointers to first LLVM BB & Instruction in function.
2033   StackFrame.CurBB     = F->begin();
2034   StackFrame.CurInst   = StackFrame.CurBB->begin();
2035 
2036   // Run through the function arguments and initialize their values...
2037   assert((ArgVals.size() == F->arg_size() ||
2038          (ArgVals.size() > F->arg_size() && F->getFunctionType()->isVarArg()))&&
2039          "Invalid number of values passed to function invocation!");
2040 
2041   // Handle non-varargs arguments...
2042   unsigned i = 0;
2043   for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end();
2044        AI != E; ++AI, ++i)
2045     SetValue(AI, ArgVals[i], StackFrame);
2046 
2047   // Handle varargs arguments...
2048   StackFrame.VarArgs.assign(ArgVals.begin()+i, ArgVals.end());
2049 }
2050 
2051 
2052 void Interpreter::run() {
2053   while (!ECStack.empty()) {
2054     // Interpret a single instruction & increment the "PC".
2055     ExecutionContext &SF = ECStack.back();  // Current stack frame
2056     Instruction &I = *SF.CurInst++;         // Increment before execute
2057 
2058     // Track the number of dynamic instructions executed.
2059     ++NumDynamicInsts;
2060 
2061     DEBUG(dbgs() << "About to interpret: " << I);
2062     visit(I);   // Dispatch to one of the visit* methods...
2063 #if 0
2064     // This is not safe, as visiting the instruction could lower it and free I.
2065 DEBUG(
2066     if (!isa<CallInst>(I) && !isa<InvokeInst>(I) &&
2067         I.getType() != Type::VoidTy) {
2068       dbgs() << "  --> ";
2069       const GenericValue &Val = SF.Values[&I];
2070       switch (I.getType()->getTypeID()) {
2071       default: llvm_unreachable("Invalid GenericValue Type");
2072       case Type::VoidTyID:    dbgs() << "void"; break;
2073       case Type::FloatTyID:   dbgs() << "float " << Val.FloatVal; break;
2074       case Type::DoubleTyID:  dbgs() << "double " << Val.DoubleVal; break;
2075       case Type::PointerTyID: dbgs() << "void* " << intptr_t(Val.PointerVal);
2076         break;
2077       case Type::IntegerTyID:
2078         dbgs() << "i" << Val.IntVal.getBitWidth() << " "
2079                << Val.IntVal.toStringUnsigned(10)
2080                << " (0x" << Val.IntVal.toStringUnsigned(16) << ")\n";
2081         break;
2082       }
2083     });
2084 #endif
2085   }
2086 }
2087