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1 //===-- Instruction.cpp - Implement the Instruction class -----------------===//
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 implements the Instruction class for the VMCore library.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/Instruction.h"
15 #include "llvm/Type.h"
16 #include "llvm/Instructions.h"
17 #include "llvm/Constants.h"
18 #include "llvm/Module.h"
19 #include "llvm/Support/CallSite.h"
20 #include "llvm/Support/LeakDetector.h"
21 using namespace llvm;
22 
Instruction(Type * ty,unsigned it,Use * Ops,unsigned NumOps,Instruction * InsertBefore)23 Instruction::Instruction(Type *ty, unsigned it, Use *Ops, unsigned NumOps,
24                          Instruction *InsertBefore)
25   : User(ty, Value::InstructionVal + it, Ops, NumOps), Parent(0) {
26   // Make sure that we get added to a basicblock
27   LeakDetector::addGarbageObject(this);
28 
29   // If requested, insert this instruction into a basic block...
30   if (InsertBefore) {
31     assert(InsertBefore->getParent() &&
32            "Instruction to insert before is not in a basic block!");
33     InsertBefore->getParent()->getInstList().insert(InsertBefore, this);
34   }
35 }
36 
Instruction(Type * ty,unsigned it,Use * Ops,unsigned NumOps,BasicBlock * InsertAtEnd)37 Instruction::Instruction(Type *ty, unsigned it, Use *Ops, unsigned NumOps,
38                          BasicBlock *InsertAtEnd)
39   : User(ty, Value::InstructionVal + it, Ops, NumOps), Parent(0) {
40   // Make sure that we get added to a basicblock
41   LeakDetector::addGarbageObject(this);
42 
43   // append this instruction into the basic block
44   assert(InsertAtEnd && "Basic block to append to may not be NULL!");
45   InsertAtEnd->getInstList().push_back(this);
46 }
47 
48 
49 // Out of line virtual method, so the vtable, etc has a home.
~Instruction()50 Instruction::~Instruction() {
51   assert(Parent == 0 && "Instruction still linked in the program!");
52   if (hasMetadataHashEntry())
53     clearMetadataHashEntries();
54 }
55 
56 
setParent(BasicBlock * P)57 void Instruction::setParent(BasicBlock *P) {
58   if (getParent()) {
59     if (!P) LeakDetector::addGarbageObject(this);
60   } else {
61     if (P) LeakDetector::removeGarbageObject(this);
62   }
63 
64   Parent = P;
65 }
66 
removeFromParent()67 void Instruction::removeFromParent() {
68   getParent()->getInstList().remove(this);
69 }
70 
eraseFromParent()71 void Instruction::eraseFromParent() {
72   getParent()->getInstList().erase(this);
73 }
74 
75 /// insertBefore - Insert an unlinked instructions into a basic block
76 /// immediately before the specified instruction.
insertBefore(Instruction * InsertPos)77 void Instruction::insertBefore(Instruction *InsertPos) {
78   InsertPos->getParent()->getInstList().insert(InsertPos, this);
79 }
80 
81 /// insertAfter - Insert an unlinked instructions into a basic block
82 /// immediately after the specified instruction.
insertAfter(Instruction * InsertPos)83 void Instruction::insertAfter(Instruction *InsertPos) {
84   InsertPos->getParent()->getInstList().insertAfter(InsertPos, this);
85 }
86 
87 /// moveBefore - Unlink this instruction from its current basic block and
88 /// insert it into the basic block that MovePos lives in, right before
89 /// MovePos.
moveBefore(Instruction * MovePos)90 void Instruction::moveBefore(Instruction *MovePos) {
91   MovePos->getParent()->getInstList().splice(MovePos,getParent()->getInstList(),
92                                              this);
93 }
94 
95 
getOpcodeName(unsigned OpCode)96 const char *Instruction::getOpcodeName(unsigned OpCode) {
97   switch (OpCode) {
98   // Terminators
99   case Ret:    return "ret";
100   case Br:     return "br";
101   case Switch: return "switch";
102   case IndirectBr: return "indirectbr";
103   case Invoke: return "invoke";
104   case Resume: return "resume";
105   case Unreachable: return "unreachable";
106 
107   // Standard binary operators...
108   case Add: return "add";
109   case FAdd: return "fadd";
110   case Sub: return "sub";
111   case FSub: return "fsub";
112   case Mul: return "mul";
113   case FMul: return "fmul";
114   case UDiv: return "udiv";
115   case SDiv: return "sdiv";
116   case FDiv: return "fdiv";
117   case URem: return "urem";
118   case SRem: return "srem";
119   case FRem: return "frem";
120 
121   // Logical operators...
122   case And: return "and";
123   case Or : return "or";
124   case Xor: return "xor";
125 
126   // Memory instructions...
127   case Alloca:        return "alloca";
128   case Load:          return "load";
129   case Store:         return "store";
130   case AtomicCmpXchg: return "cmpxchg";
131   case AtomicRMW:     return "atomicrmw";
132   case Fence:         return "fence";
133   case GetElementPtr: return "getelementptr";
134 
135   // Convert instructions...
136   case Trunc:     return "trunc";
137   case ZExt:      return "zext";
138   case SExt:      return "sext";
139   case FPTrunc:   return "fptrunc";
140   case FPExt:     return "fpext";
141   case FPToUI:    return "fptoui";
142   case FPToSI:    return "fptosi";
143   case UIToFP:    return "uitofp";
144   case SIToFP:    return "sitofp";
145   case IntToPtr:  return "inttoptr";
146   case PtrToInt:  return "ptrtoint";
147   case BitCast:   return "bitcast";
148 
149   // Other instructions...
150   case ICmp:           return "icmp";
151   case FCmp:           return "fcmp";
152   case PHI:            return "phi";
153   case Select:         return "select";
154   case Call:           return "call";
155   case Shl:            return "shl";
156   case LShr:           return "lshr";
157   case AShr:           return "ashr";
158   case VAArg:          return "va_arg";
159   case ExtractElement: return "extractelement";
160   case InsertElement:  return "insertelement";
161   case ShuffleVector:  return "shufflevector";
162   case ExtractValue:   return "extractvalue";
163   case InsertValue:    return "insertvalue";
164   case LandingPad:     return "landingpad";
165 
166   default: return "<Invalid operator> ";
167   }
168 }
169 
170 /// isIdenticalTo - Return true if the specified instruction is exactly
171 /// identical to the current one.  This means that all operands match and any
172 /// extra information (e.g. load is volatile) agree.
isIdenticalTo(const Instruction * I) const173 bool Instruction::isIdenticalTo(const Instruction *I) const {
174   return isIdenticalToWhenDefined(I) &&
175          SubclassOptionalData == I->SubclassOptionalData;
176 }
177 
178 /// isIdenticalToWhenDefined - This is like isIdenticalTo, except that it
179 /// ignores the SubclassOptionalData flags, which specify conditions
180 /// under which the instruction's result is undefined.
isIdenticalToWhenDefined(const Instruction * I) const181 bool Instruction::isIdenticalToWhenDefined(const Instruction *I) const {
182   if (getOpcode() != I->getOpcode() ||
183       getNumOperands() != I->getNumOperands() ||
184       getType() != I->getType())
185     return false;
186 
187   // We have two instructions of identical opcode and #operands.  Check to see
188   // if all operands are the same.
189   for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
190     if (getOperand(i) != I->getOperand(i))
191       return false;
192 
193   // Check special state that is a part of some instructions.
194   if (const LoadInst *LI = dyn_cast<LoadInst>(this))
195     return LI->isVolatile() == cast<LoadInst>(I)->isVolatile() &&
196            LI->getAlignment() == cast<LoadInst>(I)->getAlignment() &&
197            LI->getOrdering() == cast<LoadInst>(I)->getOrdering() &&
198            LI->getSynchScope() == cast<LoadInst>(I)->getSynchScope();
199   if (const StoreInst *SI = dyn_cast<StoreInst>(this))
200     return SI->isVolatile() == cast<StoreInst>(I)->isVolatile() &&
201            SI->getAlignment() == cast<StoreInst>(I)->getAlignment() &&
202            SI->getOrdering() == cast<StoreInst>(I)->getOrdering() &&
203            SI->getSynchScope() == cast<StoreInst>(I)->getSynchScope();
204   if (const CmpInst *CI = dyn_cast<CmpInst>(this))
205     return CI->getPredicate() == cast<CmpInst>(I)->getPredicate();
206   if (const CallInst *CI = dyn_cast<CallInst>(this))
207     return CI->isTailCall() == cast<CallInst>(I)->isTailCall() &&
208            CI->getCallingConv() == cast<CallInst>(I)->getCallingConv() &&
209            CI->getAttributes() == cast<CallInst>(I)->getAttributes();
210   if (const InvokeInst *CI = dyn_cast<InvokeInst>(this))
211     return CI->getCallingConv() == cast<InvokeInst>(I)->getCallingConv() &&
212            CI->getAttributes() == cast<InvokeInst>(I)->getAttributes();
213   if (const InsertValueInst *IVI = dyn_cast<InsertValueInst>(this))
214     return IVI->getIndices() == cast<InsertValueInst>(I)->getIndices();
215   if (const ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(this))
216     return EVI->getIndices() == cast<ExtractValueInst>(I)->getIndices();
217   if (const FenceInst *FI = dyn_cast<FenceInst>(this))
218     return FI->getOrdering() == cast<FenceInst>(FI)->getOrdering() &&
219            FI->getSynchScope() == cast<FenceInst>(FI)->getSynchScope();
220   if (const AtomicCmpXchgInst *CXI = dyn_cast<AtomicCmpXchgInst>(this))
221     return CXI->isVolatile() == cast<AtomicCmpXchgInst>(I)->isVolatile() &&
222            CXI->getOrdering() == cast<AtomicCmpXchgInst>(I)->getOrdering() &&
223            CXI->getSynchScope() == cast<AtomicCmpXchgInst>(I)->getSynchScope();
224   if (const AtomicRMWInst *RMWI = dyn_cast<AtomicRMWInst>(this))
225     return RMWI->getOperation() == cast<AtomicRMWInst>(I)->getOperation() &&
226            RMWI->isVolatile() == cast<AtomicRMWInst>(I)->isVolatile() &&
227            RMWI->getOrdering() == cast<AtomicRMWInst>(I)->getOrdering() &&
228            RMWI->getSynchScope() == cast<AtomicRMWInst>(I)->getSynchScope();
229 
230   return true;
231 }
232 
233 // isSameOperationAs
234 // This should be kept in sync with isEquivalentOperation in
235 // lib/Transforms/IPO/MergeFunctions.cpp.
isSameOperationAs(const Instruction * I) const236 bool Instruction::isSameOperationAs(const Instruction *I) const {
237   if (getOpcode() != I->getOpcode() ||
238       getNumOperands() != I->getNumOperands() ||
239       getType() != I->getType())
240     return false;
241 
242   // We have two instructions of identical opcode and #operands.  Check to see
243   // if all operands are the same type
244   for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
245     if (getOperand(i)->getType() != I->getOperand(i)->getType())
246       return false;
247 
248   // Check special state that is a part of some instructions.
249   if (const LoadInst *LI = dyn_cast<LoadInst>(this))
250     return LI->isVolatile() == cast<LoadInst>(I)->isVolatile() &&
251            LI->getAlignment() == cast<LoadInst>(I)->getAlignment() &&
252            LI->getOrdering() == cast<LoadInst>(I)->getOrdering() &&
253            LI->getSynchScope() == cast<LoadInst>(I)->getSynchScope();
254   if (const StoreInst *SI = dyn_cast<StoreInst>(this))
255     return SI->isVolatile() == cast<StoreInst>(I)->isVolatile() &&
256            SI->getAlignment() == cast<StoreInst>(I)->getAlignment() &&
257            SI->getOrdering() == cast<StoreInst>(I)->getOrdering() &&
258            SI->getSynchScope() == cast<StoreInst>(I)->getSynchScope();
259   if (const CmpInst *CI = dyn_cast<CmpInst>(this))
260     return CI->getPredicate() == cast<CmpInst>(I)->getPredicate();
261   if (const CallInst *CI = dyn_cast<CallInst>(this))
262     return CI->isTailCall() == cast<CallInst>(I)->isTailCall() &&
263            CI->getCallingConv() == cast<CallInst>(I)->getCallingConv() &&
264            CI->getAttributes() == cast<CallInst>(I)->getAttributes();
265   if (const InvokeInst *CI = dyn_cast<InvokeInst>(this))
266     return CI->getCallingConv() == cast<InvokeInst>(I)->getCallingConv() &&
267            CI->getAttributes() ==
268              cast<InvokeInst>(I)->getAttributes();
269   if (const InsertValueInst *IVI = dyn_cast<InsertValueInst>(this))
270     return IVI->getIndices() == cast<InsertValueInst>(I)->getIndices();
271   if (const ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(this))
272     return EVI->getIndices() == cast<ExtractValueInst>(I)->getIndices();
273   if (const FenceInst *FI = dyn_cast<FenceInst>(this))
274     return FI->getOrdering() == cast<FenceInst>(I)->getOrdering() &&
275            FI->getSynchScope() == cast<FenceInst>(I)->getSynchScope();
276   if (const AtomicCmpXchgInst *CXI = dyn_cast<AtomicCmpXchgInst>(this))
277     return CXI->isVolatile() == cast<AtomicCmpXchgInst>(I)->isVolatile() &&
278            CXI->getOrdering() == cast<AtomicCmpXchgInst>(I)->getOrdering() &&
279            CXI->getSynchScope() == cast<AtomicCmpXchgInst>(I)->getSynchScope();
280   if (const AtomicRMWInst *RMWI = dyn_cast<AtomicRMWInst>(this))
281     return RMWI->getOperation() == cast<AtomicRMWInst>(I)->getOperation() &&
282            RMWI->isVolatile() == cast<AtomicRMWInst>(I)->isVolatile() &&
283            RMWI->getOrdering() == cast<AtomicRMWInst>(I)->getOrdering() &&
284            RMWI->getSynchScope() == cast<AtomicRMWInst>(I)->getSynchScope();
285 
286   return true;
287 }
288 
289 /// isUsedOutsideOfBlock - Return true if there are any uses of I outside of the
290 /// specified block.  Note that PHI nodes are considered to evaluate their
291 /// operands in the corresponding predecessor block.
isUsedOutsideOfBlock(const BasicBlock * BB) const292 bool Instruction::isUsedOutsideOfBlock(const BasicBlock *BB) const {
293   for (const_use_iterator UI = use_begin(), E = use_end(); UI != E; ++UI) {
294     // PHI nodes uses values in the corresponding predecessor block.  For other
295     // instructions, just check to see whether the parent of the use matches up.
296     const User *U = *UI;
297     const PHINode *PN = dyn_cast<PHINode>(U);
298     if (PN == 0) {
299       if (cast<Instruction>(U)->getParent() != BB)
300         return true;
301       continue;
302     }
303 
304     if (PN->getIncomingBlock(UI) != BB)
305       return true;
306   }
307   return false;
308 }
309 
310 /// mayReadFromMemory - Return true if this instruction may read memory.
311 ///
mayReadFromMemory() const312 bool Instruction::mayReadFromMemory() const {
313   switch (getOpcode()) {
314   default: return false;
315   case Instruction::VAArg:
316   case Instruction::Load:
317   case Instruction::Fence: // FIXME: refine definition of mayReadFromMemory
318   case Instruction::AtomicCmpXchg:
319   case Instruction::AtomicRMW:
320     return true;
321   case Instruction::Call:
322     return !cast<CallInst>(this)->doesNotAccessMemory();
323   case Instruction::Invoke:
324     return !cast<InvokeInst>(this)->doesNotAccessMemory();
325   case Instruction::Store:
326     return !cast<StoreInst>(this)->isUnordered();
327   }
328 }
329 
330 /// mayWriteToMemory - Return true if this instruction may modify memory.
331 ///
mayWriteToMemory() const332 bool Instruction::mayWriteToMemory() const {
333   switch (getOpcode()) {
334   default: return false;
335   case Instruction::Fence: // FIXME: refine definition of mayWriteToMemory
336   case Instruction::Store:
337   case Instruction::VAArg:
338   case Instruction::AtomicCmpXchg:
339   case Instruction::AtomicRMW:
340     return true;
341   case Instruction::Call:
342     return !cast<CallInst>(this)->onlyReadsMemory();
343   case Instruction::Invoke:
344     return !cast<InvokeInst>(this)->onlyReadsMemory();
345   case Instruction::Load:
346     return !cast<LoadInst>(this)->isUnordered();
347   }
348 }
349 
350 /// mayThrow - Return true if this instruction may throw an exception.
351 ///
mayThrow() const352 bool Instruction::mayThrow() const {
353   if (const CallInst *CI = dyn_cast<CallInst>(this))
354     return !CI->doesNotThrow();
355   return isa<ResumeInst>(this);
356 }
357 
358 /// isAssociative - Return true if the instruction is associative:
359 ///
360 ///   Associative operators satisfy:  x op (y op z) === (x op y) op z
361 ///
362 /// In LLVM, the Add, Mul, And, Or, and Xor operators are associative.
363 ///
isAssociative(unsigned Opcode)364 bool Instruction::isAssociative(unsigned Opcode) {
365   return Opcode == And || Opcode == Or || Opcode == Xor ||
366          Opcode == Add || Opcode == Mul;
367 }
368 
369 /// isCommutative - Return true if the instruction is commutative:
370 ///
371 ///   Commutative operators satisfy: (x op y) === (y op x)
372 ///
373 /// In LLVM, these are the associative operators, plus SetEQ and SetNE, when
374 /// applied to any type.
375 ///
isCommutative(unsigned op)376 bool Instruction::isCommutative(unsigned op) {
377   switch (op) {
378   case Add:
379   case FAdd:
380   case Mul:
381   case FMul:
382   case And:
383   case Or:
384   case Xor:
385     return true;
386   default:
387     return false;
388   }
389 }
390 
clone() const391 Instruction *Instruction::clone() const {
392   Instruction *New = clone_impl();
393   New->SubclassOptionalData = SubclassOptionalData;
394   if (!hasMetadata())
395     return New;
396 
397   // Otherwise, enumerate and copy over metadata from the old instruction to the
398   // new one.
399   SmallVector<std::pair<unsigned, MDNode*>, 4> TheMDs;
400   getAllMetadataOtherThanDebugLoc(TheMDs);
401   for (unsigned i = 0, e = TheMDs.size(); i != e; ++i)
402     New->setMetadata(TheMDs[i].first, TheMDs[i].second);
403 
404   New->setDebugLoc(getDebugLoc());
405   return New;
406 }
407