1 //===-- Verifier.cpp - Implement the Module Verifier -------------*- C++ -*-==//
3 // This file defines the function verifier interface, that can be used for some
4 // sanity checking of input to the system.
6 // Note that this does not provide full 'java style' security and verifications,
7 // instead it just tries to ensure that code is well formed.
9 // * Both of a binary operator's parameters are the same type
10 // * Verify that the indices of mem access instructions match other operands
11 // * Verify that arithmetic and other things are only performed on first class
12 // types. Verify that shifts & logicals only happen on integrals f.e.
13 // . All of the constants in a switch statement are of the correct type
14 // * The code is in valid SSA form
15 // . It should be illegal to put a label into any other type (like a structure)
16 // or to return one. [except constant arrays!]
17 // * Only phi nodes can be self referential: 'add int %0, %0 ; <int>:0' is bad
18 // * PHI nodes must have an entry for each predecessor, with no extras.
19 // * PHI nodes must be the first thing in a basic block, all grouped together
20 // * PHI nodes must have at least one entry
21 // * All basic blocks should only end with terminator insts, not contain them
22 // * The entry node to a function must not have predecessors
23 // * All Instructions must be embeded into a basic block
24 // . Function's cannot take a void typed parameter
25 // * Verify that a function's argument list agrees with it's declared type.
26 // . Verify that arrays and structures have fixed elements: No unsized arrays.
27 // * It is illegal to specify a name for a void value.
28 // * It is illegal to have a internal global value with no intitalizer
29 // * It is illegal to have a ret instruction that returns a value that does not
30 // agree with the function return value type.
31 // * Function call argument types match the function prototype
32 // * All other things that are tested by asserts spread about the code...
34 //===----------------------------------------------------------------------===//
36 #include "llvm/Analysis/Verifier.h"
37 #include "llvm/Pass.h"
38 #include "llvm/Module.h"
39 #include "llvm/DerivedTypes.h"
40 #include "llvm/iPHINode.h"
41 #include "llvm/iTerminators.h"
42 #include "llvm/iOther.h"
43 #include "llvm/iOperators.h"
44 #include "llvm/iMemory.h"
45 #include "llvm/SymbolTable.h"
46 #include "llvm/PassManager.h"
47 #include "llvm/Analysis/Dominators.h"
48 #include "llvm/Support/CFG.h"
49 #include "llvm/Support/InstVisitor.h"
50 #include "Support/STLExtras.h"
53 namespace { // Anonymous namespace for class
55 struct Verifier : public FunctionPass, InstVisitor<Verifier> {
56 bool Broken; // Is this module found to be broken?
57 bool RealPass; // Are we not being run by a PassManager?
58 bool AbortBroken; // If broken, should it or should it not abort?
60 DominatorSet *DS; // Dominator set, caution can be null!
62 Verifier() : Broken(false), RealPass(true), AbortBroken(true), DS(0) {}
63 Verifier(bool AB) : Broken(false), RealPass(true), AbortBroken(AB), DS(0) {}
64 Verifier(DominatorSet &ds)
65 : Broken(false), RealPass(false), AbortBroken(false), DS(&ds) {}
68 bool doInitialization(Module &M) {
69 verifySymbolTable(M.getSymbolTable());
71 // If this is a real pass, in a pass manager, we must abort before
72 // returning back to the pass manager, or else the pass manager may try to
73 // run other passes on the broken module.
80 bool runOnFunction(Function &F) {
81 // Get dominator information if we are being run by PassManager
82 if (RealPass) DS = &getAnalysis<DominatorSet>();
85 // If this is a real pass, in a pass manager, we must abort before
86 // returning back to the pass manager, or else the pass manager may try to
87 // run other passes on the broken module.
95 bool doFinalization(Module &M) {
96 // Scan through, checking all of the external function's linkage now...
97 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
98 if (I->isExternal() && I->hasInternalLinkage())
99 CheckFailed("Function Declaration has Internal Linkage!", I);
101 for (Module::giterator I = M.gbegin(), E = M.gend(); I != E; ++I)
102 if (I->isExternal() && I->hasInternalLinkage())
103 CheckFailed("Global Variable is external with internal linkage!", I);
105 // If the module is broken, abort at this time.
110 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
111 AU.setPreservesAll();
113 AU.addRequired<DominatorSet>();
116 // abortIfBroken - If the module is broken and we are supposed to abort on
117 // this condition, do so.
119 void abortIfBroken() const {
120 if (Broken && AbortBroken) {
121 std::cerr << "Broken module found, compilation aborted!\n";
126 // Verification methods...
127 void verifySymbolTable(SymbolTable *ST);
128 void visitFunction(Function &F);
129 void visitBasicBlock(BasicBlock &BB);
130 void visitPHINode(PHINode &PN);
131 void visitBinaryOperator(BinaryOperator &B);
132 void visitShiftInst(ShiftInst &SI);
133 void visitCallInst(CallInst &CI);
134 void visitGetElementPtrInst(GetElementPtrInst &GEP);
135 void visitLoadInst(LoadInst &LI);
136 void visitStoreInst(StoreInst &SI);
137 void visitInstruction(Instruction &I);
138 void visitTerminatorInst(TerminatorInst &I);
139 void visitReturnInst(ReturnInst &RI);
141 // CheckFailed - A check failed, so print out the condition and the message
142 // that failed. This provides a nice place to put a breakpoint if you want
143 // to see why something is not correct.
145 inline void CheckFailed(const std::string &Message,
146 const Value *V1 = 0, const Value *V2 = 0,
147 const Value *V3 = 0, const Value *V4 = 0) {
148 std::cerr << Message << "\n";
149 if (V1) std::cerr << *V1 << "\n";
150 if (V2) std::cerr << *V2 << "\n";
151 if (V3) std::cerr << *V3 << "\n";
152 if (V4) std::cerr << *V4 << "\n";
157 RegisterPass<Verifier> X("verify", "Module Verifier");
160 // Assert - We know that cond should be true, if not print an error message.
161 #define Assert(C, M) \
162 do { if (!(C)) { CheckFailed(M); return; } } while (0)
163 #define Assert1(C, M, V1) \
164 do { if (!(C)) { CheckFailed(M, V1); return; } } while (0)
165 #define Assert2(C, M, V1, V2) \
166 do { if (!(C)) { CheckFailed(M, V1, V2); return; } } while (0)
167 #define Assert3(C, M, V1, V2, V3) \
168 do { if (!(C)) { CheckFailed(M, V1, V2, V3); return; } } while (0)
169 #define Assert4(C, M, V1, V2, V3, V4) \
170 do { if (!(C)) { CheckFailed(M, V1, V2, V3, V4); return; } } while (0)
173 // verifySymbolTable - Verify that a function or module symbol table is ok
175 void Verifier::verifySymbolTable(SymbolTable *ST) {
176 if (ST == 0) return; // No symbol table to process
178 // Loop over all of the types in the symbol table...
179 for (SymbolTable::iterator TI = ST->begin(), TE = ST->end(); TI != TE; ++TI)
180 for (SymbolTable::type_iterator I = TI->second.begin(),
181 E = TI->second.end(); I != E; ++I) {
182 Value *V = I->second;
184 // Check that there are no void typed values in the symbol table. Values
185 // with a void type cannot be put into symbol tables because they cannot
187 Assert1(V->getType() != Type::VoidTy,
188 "Values with void type are not allowed to have names!", V);
193 // visitFunction - Verify that a function is ok.
195 void Verifier::visitFunction(Function &F) {
196 // Check function arguments...
197 const FunctionType *FT = F.getFunctionType();
198 unsigned NumArgs = F.getArgumentList().size();
200 Assert2(!FT->isVarArg(), "Cannot define varargs functions in LLVM!", &F, FT);
201 Assert2(FT->getNumParams() == NumArgs,
202 "# formal arguments must match # of arguments for function type!",
205 // Check that the argument values match the function type for this function...
207 for (Function::aiterator I = F.abegin(), E = F.aend(); I != E; ++I, ++i)
208 Assert2(I->getType() == FT->getParamType(i),
209 "Argument value does not match function argument type!",
210 I, FT->getParamType(i));
212 if (!F.isExternal()) {
213 verifySymbolTable(F.getSymbolTable());
215 // Check the entry node
216 BasicBlock *Entry = &F.getEntryNode();
217 Assert1(pred_begin(Entry) == pred_end(Entry),
218 "Entry block to function must not have predecessors!", Entry);
223 // verifyBasicBlock - Verify that a basic block is well formed...
225 void Verifier::visitBasicBlock(BasicBlock &BB) {
226 // Ensure that basic blocks have terminators!
227 Assert1(BB.getTerminator(), "Basic Block does not have terminator!", &BB);
230 void Verifier::visitTerminatorInst(TerminatorInst &I) {
231 // Ensure that terminators only exist at the end of the basic block.
232 Assert1(&I == I.getParent()->getTerminator(),
233 "Terminator found in the middle of a basic block!", I.getParent());
237 void Verifier::visitReturnInst(ReturnInst &RI) {
238 Function *F = RI.getParent()->getParent();
239 if (RI.getNumOperands() == 0)
240 Assert1(F->getReturnType() == Type::VoidTy,
241 "Function returns no value, but ret instruction found that does!",
244 Assert2(F->getReturnType() == RI.getOperand(0)->getType(),
245 "Function return type does not match operand "
246 "type of return inst!", &RI, F->getReturnType());
248 // Check to make sure that the return value has neccesary properties for
250 visitTerminatorInst(RI);
254 // visitPHINode - Ensure that a PHI node is well formed.
255 void Verifier::visitPHINode(PHINode &PN) {
256 // Ensure that the PHI nodes are all grouped together at the top of the block.
257 // This can be tested by checking whether the instruction before this is
258 // either nonexistant (because this is begin()) or is a PHI node. If not,
259 // then there is some other instruction before a PHI.
260 Assert2(PN.getPrev() == 0 || isa<PHINode>(PN.getPrev()),
261 "PHI nodes not grouped at top of basic block!",
262 &PN, PN.getParent());
264 // Ensure that PHI nodes have at least one entry!
265 Assert1(PN.getNumIncomingValues() != 0,
266 "PHI nodes must have at least one entry. If the block is dead, "
267 "the PHI should be removed!",
270 std::vector<BasicBlock*> Preds(pred_begin(PN.getParent()),
271 pred_end(PN.getParent()));
272 // Loop over all of the incoming values, make sure that there are
273 // predecessors for each one...
275 for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
276 // Make sure all of the incoming values are the right types...
277 Assert2(PN.getType() == PN.getIncomingValue(i)->getType(),
278 "PHI node argument type does not agree with PHI node type!",
279 &PN, PN.getIncomingValue(i));
281 BasicBlock *BB = PN.getIncomingBlock(i);
282 std::vector<BasicBlock*>::iterator PI =
283 find(Preds.begin(), Preds.end(), BB);
284 Assert2(PI != Preds.end(), "PHI node has entry for basic block that"
285 " is not a predecessor!", &PN, BB);
289 // There should be no entries left in the predecessor list...
290 for (std::vector<BasicBlock*>::iterator I = Preds.begin(),
291 E = Preds.end(); I != E; ++I)
292 Assert2(0, "PHI node does not have entry for a predecessor basic block!",
295 // Now we go through and check to make sure that if there is more than one
296 // entry for a particular basic block in this PHI node, that the incoming
297 // values are all identical.
299 std::vector<std::pair<BasicBlock*, Value*> > Values;
300 Values.reserve(PN.getNumIncomingValues());
301 for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i)
302 Values.push_back(std::make_pair(PN.getIncomingBlock(i),
303 PN.getIncomingValue(i)));
305 // Sort the Values vector so that identical basic block entries are adjacent.
306 std::sort(Values.begin(), Values.end());
308 // Check for identical basic blocks with differing incoming values...
309 for (unsigned i = 1, e = PN.getNumIncomingValues(); i < e; ++i)
310 Assert4(Values[i].first != Values[i-1].first ||
311 Values[i].second == Values[i-1].second,
312 "PHI node has multiple entries for the same basic block with "
313 "different incoming values!", &PN, Values[i].first,
314 Values[i].second, Values[i-1].second);
316 visitInstruction(PN);
319 void Verifier::visitCallInst(CallInst &CI) {
320 Assert1(isa<PointerType>(CI.getOperand(0)->getType()),
321 "Called function must be a pointer!", &CI);
322 const PointerType *FPTy = cast<PointerType>(CI.getOperand(0)->getType());
323 Assert1(isa<FunctionType>(FPTy->getElementType()),
324 "Called function is not pointer to function type!", &CI);
326 const FunctionType *FTy = cast<FunctionType>(FPTy->getElementType());
328 // Verify that the correct number of arguments are being passed
330 Assert1(CI.getNumOperands()-1 >= FTy->getNumParams(),
331 "Called function requires more parameters than were provided!",&CI);
333 Assert1(CI.getNumOperands()-1 == FTy->getNumParams(),
334 "Incorrect number of arguments passed to called function!", &CI);
336 // Verify that all arguments to the call match the function type...
337 for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
338 Assert2(CI.getOperand(i+1)->getType() == FTy->getParamType(i),
339 "Call parameter type does not match function signature!",
340 CI.getOperand(i+1), FTy->getParamType(i));
342 visitInstruction(CI);
345 // visitBinaryOperator - Check that both arguments to the binary operator are
348 void Verifier::visitBinaryOperator(BinaryOperator &B) {
349 Assert1(B.getOperand(0)->getType() == B.getOperand(1)->getType(),
350 "Both operands to a binary operator are not of the same type!", &B);
352 // Check that logical operators are only used with integral operands.
353 if (B.getOpcode() == Instruction::And || B.getOpcode() == Instruction::Or ||
354 B.getOpcode() == Instruction::Xor) {
355 Assert1(B.getType()->isIntegral(),
356 "Logical operators only work with integral types!", &B);
357 Assert1(B.getType() == B.getOperand(0)->getType(),
358 "Logical operators must have same type for operands and result!",
360 } else if (isa<SetCondInst>(B)) {
361 // Check that setcc instructions return bool
362 Assert1(B.getType() == Type::BoolTy,
363 "setcc instructions must return boolean values!", &B);
365 // Arithmetic operators only work on integer or fp values
366 Assert1(B.getType() == B.getOperand(0)->getType(),
367 "Arithmetic operators must have same type for operands and result!",
369 Assert1(B.getType()->isInteger() || B.getType()->isFloatingPoint(),
370 "Arithmetic operators must have integer or fp type!", &B);
376 void Verifier::visitShiftInst(ShiftInst &SI) {
377 Assert1(SI.getType()->isInteger(),
378 "Shift must return an integer result!", &SI);
379 Assert1(SI.getType() == SI.getOperand(0)->getType(),
380 "Shift return type must be same as first operand!", &SI);
381 Assert1(SI.getOperand(1)->getType() == Type::UByteTy,
382 "Second operand to shift must be ubyte type!", &SI);
383 visitInstruction(SI);
388 void Verifier::visitGetElementPtrInst(GetElementPtrInst &GEP) {
390 GetElementPtrInst::getIndexedType(GEP.getOperand(0)->getType(),
391 std::vector<Value*>(GEP.idx_begin(), GEP.idx_end()), true);
392 Assert1(ElTy, "Invalid indices for GEP pointer type!", &GEP);
393 Assert2(PointerType::get(ElTy) == GEP.getType(),
394 "GEP is not of right type for indices!", &GEP, ElTy);
395 visitInstruction(GEP);
398 void Verifier::visitLoadInst(LoadInst &LI) {
400 cast<PointerType>(LI.getOperand(0)->getType())->getElementType();
401 Assert2(ElTy == LI.getType(),
402 "Load is not of right type for indices!", &LI, ElTy);
403 visitInstruction(LI);
406 void Verifier::visitStoreInst(StoreInst &SI) {
408 cast<PointerType>(SI.getOperand(1)->getType())->getElementType();
409 Assert2(ElTy == SI.getOperand(0)->getType(),
410 "Stored value is not of right type for indices!", &SI, ElTy);
411 visitInstruction(SI);
415 // verifyInstruction - Verify that an instruction is well formed.
417 void Verifier::visitInstruction(Instruction &I) {
418 BasicBlock *BB = I.getParent();
419 Assert1(BB, "Instruction not embedded in basic block!", &I);
421 // Check that all uses of the instruction, if they are instructions
422 // themselves, actually have parent basic blocks. If the use is not an
423 // instruction, it is an error!
425 for (User::use_iterator UI = I.use_begin(), UE = I.use_end();
427 Assert1(isa<Instruction>(*UI), "Use of instruction is not an instruction!",
429 Instruction *Used = cast<Instruction>(*UI);
430 Assert2(Used->getParent() != 0, "Instruction referencing instruction not"
431 " embeded in a basic block!", &I, Used);
434 if (!isa<PHINode>(I)) { // Check that non-phi nodes are not self referential
435 for (Value::use_iterator UI = I.use_begin(), UE = I.use_end();
437 Assert1(*UI != (User*)&I,
438 "Only PHI nodes may reference their own value!", &I);
441 // Check that void typed values don't have names
442 Assert1(I.getType() != Type::VoidTy || !I.hasName(),
443 "Instruction has a name, but provides a void value!", &I);
445 // Check that a definition dominates all of its uses.
447 for (User::use_iterator UI = I.use_begin(), UE = I.use_end();
449 Instruction *Use = cast<Instruction>(*UI);
451 // PHI nodes are more difficult than other nodes because they actually
452 // "use" the value in the predecessor basic blocks they correspond to.
453 if (PHINode *PN = dyn_cast<PHINode>(Use)) {
454 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
455 if (&I == PN->getIncomingValue(i)) {
456 // Make sure that I dominates the end of pred(i)
457 BasicBlock *Pred = PN->getIncomingBlock(i);
459 // Use must be dominated by by definition unless use is unreachable!
460 Assert2(DS->dominates(BB, Pred) ||
461 !DS->dominates(&BB->getParent()->getEntryNode(), Pred),
462 "Instruction does not dominate all uses!",
467 // Use must be dominated by by definition unless use is unreachable!
468 Assert2(DS->dominates(&I, Use) ||
469 !DS->dominates(&BB->getParent()->getEntryNode(),Use->getParent()),
470 "Instruction does not dominate all uses!", &I, Use);
476 //===----------------------------------------------------------------------===//
477 // Implement the public interfaces to this file...
478 //===----------------------------------------------------------------------===//
480 Pass *createVerifierPass() {
481 return new Verifier();
485 // verifyFunction - Create
486 bool verifyFunction(const Function &f) {
487 Function &F = (Function&)f;
488 assert(!F.isExternal() && "Cannot verify external functions");
491 DS.doInitialization(*F.getParent());
497 DS.doFinalization(*F.getParent());
502 // verifyModule - Check a module for errors, printing messages on stderr.
503 // Return true if the module is corrupt.
505 bool verifyModule(const Module &M) {
507 Verifier *V = new Verifier();