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 // * All basic blocks should only end with terminator insts, not contain them
21 // * The entry node to a function must not have predecessors
22 // * All Instructions must be embeded into a basic block
23 // . Function's cannot take a void typed parameter
24 // * Verify that a function's argument list agrees with it's declared type.
25 // . Verify that arrays and structures have fixed elements: No unsized arrays.
26 // * It is illegal to specify a name for a void value.
27 // * It is illegal to have a internal function that is just a declaration
28 // * It is illegal to have a ret instruction that returns a value that does not
29 // agree with the function return value type.
30 // * Function call argument types match the function prototype
31 // * All other things that are tested by asserts spread about the code...
33 //===----------------------------------------------------------------------===//
35 #include "llvm/Analysis/Verifier.h"
36 #include "llvm/Pass.h"
37 #include "llvm/Module.h"
38 #include "llvm/DerivedTypes.h"
39 #include "llvm/iPHINode.h"
40 #include "llvm/iTerminators.h"
41 #include "llvm/iOther.h"
42 #include "llvm/iOperators.h"
43 #include "llvm/iMemory.h"
44 #include "llvm/SymbolTable.h"
45 #include "llvm/PassManager.h"
46 #include "llvm/Analysis/Dominators.h"
47 #include "llvm/Support/CFG.h"
48 #include "llvm/Support/InstVisitor.h"
49 #include "Support/STLExtras.h"
52 namespace { // Anonymous namespace for class
54 struct Verifier : public FunctionPass, InstVisitor<Verifier> {
55 bool Broken; // Is this module found to be broken?
56 bool RealPass; // Are we not being run by a PassManager?
57 bool AbortBroken; // If broken, should it or should it not abort?
59 DominatorSet *DS; // Dominator set, caution can be null!
61 Verifier() : Broken(false), RealPass(true), AbortBroken(true), DS(0) {}
62 Verifier(bool AB) : Broken(false), RealPass(true), AbortBroken(AB), DS(0) {}
63 Verifier(DominatorSet &ds)
64 : Broken(false), RealPass(false), AbortBroken(false), DS(&ds) {}
67 bool doInitialization(Module &M) {
68 verifySymbolTable(M.getSymbolTable());
70 // If this is a real pass, in a pass manager, we must abort before
71 // returning back to the pass manager, or else the pass manager may try to
72 // run other passes on the broken module.
79 bool runOnFunction(Function &F) {
80 // Get dominator information if we are being run by PassManager
81 if (RealPass) DS = &getAnalysis<DominatorSet>();
84 // If this is a real pass, in a pass manager, we must abort before
85 // returning back to the pass manager, or else the pass manager may try to
86 // run other passes on the broken module.
94 bool doFinalization(Module &M) {
95 // Scan through, checking all of the external function's linkage now...
96 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
97 if (I->isExternal() && I->hasInternalLinkage())
98 CheckFailed("Function Declaration has Internal Linkage!", I);
100 // If the module is broken, abort at this time.
105 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
106 AU.setPreservesAll();
108 AU.addRequired<DominatorSet>();
111 // abortIfBroken - If the module is broken and we are supposed to abort on
112 // this condition, do so.
114 void abortIfBroken() const {
115 if (Broken && AbortBroken) {
116 std::cerr << "Broken module found, compilation aborted!\n";
121 // Verification methods...
122 void verifySymbolTable(SymbolTable *ST);
123 void visitFunction(Function &F);
124 void visitBasicBlock(BasicBlock &BB);
125 void visitPHINode(PHINode &PN);
126 void visitBinaryOperator(BinaryOperator &B);
127 void visitShiftInst(ShiftInst &SI);
128 void visitCallInst(CallInst &CI);
129 void visitGetElementPtrInst(GetElementPtrInst &GEP);
130 void visitLoadInst(LoadInst &LI);
131 void visitStoreInst(StoreInst &SI);
132 void visitInstruction(Instruction &I);
133 void visitTerminatorInst(TerminatorInst &I);
134 void visitReturnInst(ReturnInst &RI);
136 // CheckFailed - A check failed, so print out the condition and the message
137 // that failed. This provides a nice place to put a breakpoint if you want
138 // to see why something is not correct.
140 inline void CheckFailed(const std::string &Message,
141 const Value *V1 = 0, const Value *V2 = 0,
142 const Value *V3 = 0, const Value *V4 = 0) {
143 std::cerr << Message << "\n";
144 if (V1) std::cerr << *V1 << "\n";
145 if (V2) std::cerr << *V2 << "\n";
146 if (V3) std::cerr << *V3 << "\n";
147 if (V4) std::cerr << *V4 << "\n";
152 RegisterPass<Verifier> X("verify", "Module Verifier");
155 // Assert - We know that cond should be true, if not print an error message.
156 #define Assert(C, M) \
157 do { if (!(C)) { CheckFailed(M); return; } } while (0)
158 #define Assert1(C, M, V1) \
159 do { if (!(C)) { CheckFailed(M, V1); return; } } while (0)
160 #define Assert2(C, M, V1, V2) \
161 do { if (!(C)) { CheckFailed(M, V1, V2); return; } } while (0)
162 #define Assert3(C, M, V1, V2, V3) \
163 do { if (!(C)) { CheckFailed(M, V1, V2, V3); return; } } while (0)
164 #define Assert4(C, M, V1, V2, V3, V4) \
165 do { if (!(C)) { CheckFailed(M, V1, V2, V3, V4); return; } } while (0)
168 // verifySymbolTable - Verify that a function or module symbol table is ok
170 void Verifier::verifySymbolTable(SymbolTable *ST) {
171 if (ST == 0) return; // No symbol table to process
173 // Loop over all of the types in the symbol table...
174 for (SymbolTable::iterator TI = ST->begin(), TE = ST->end(); TI != TE; ++TI)
175 for (SymbolTable::type_iterator I = TI->second.begin(),
176 E = TI->second.end(); I != E; ++I) {
177 Value *V = I->second;
179 // Check that there are no void typed values in the symbol table. Values
180 // with a void type cannot be put into symbol tables because they cannot
182 Assert1(V->getType() != Type::VoidTy,
183 "Values with void type are not allowed to have names!", V);
188 // visitFunction - Verify that a function is ok.
190 void Verifier::visitFunction(Function &F) {
191 if (F.isExternal()) return;
193 verifySymbolTable(F.getSymbolTable());
195 // Check function arguments...
196 const FunctionType *FT = F.getFunctionType();
197 unsigned NumArgs = F.getArgumentList().size();
199 Assert2(!FT->isVarArg(), "Cannot define varargs functions in LLVM!", &F, FT);
200 Assert2(FT->getParamTypes().size() == NumArgs,
201 "# formal arguments must match # of arguments for function type!",
204 // Check that the argument values match the function type for this function...
205 if (FT->getParamTypes().size() == NumArgs) {
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));
213 // Check the entry node
214 BasicBlock *Entry = &F.getEntryNode();
215 Assert1(pred_begin(Entry) == pred_end(Entry),
216 "Entry block to function must not have predecessors!", Entry);
220 // verifyBasicBlock - Verify that a basic block is well formed...
222 void Verifier::visitBasicBlock(BasicBlock &BB) {
223 // Ensure that basic blocks have terminators!
224 Assert1(BB.getTerminator(), "Basic Block does not have terminator!", &BB);
227 void Verifier::visitTerminatorInst(TerminatorInst &I) {
228 // Ensure that terminators only exist at the end of the basic block.
229 Assert1(&I == I.getParent()->getTerminator(),
230 "Terminator found in the middle of a basic block!", I.getParent());
234 void Verifier::visitReturnInst(ReturnInst &RI) {
235 Function *F = RI.getParent()->getParent();
236 if (RI.getNumOperands() == 0)
237 Assert1(F->getReturnType() == Type::VoidTy,
238 "Function returns no value, but ret instruction found that does!",
241 Assert2(F->getReturnType() == RI.getOperand(0)->getType(),
242 "Function return type does not match operand "
243 "type of return inst!", &RI, F->getReturnType());
245 // Check to make sure that the return value has neccesary properties for
247 visitTerminatorInst(RI);
251 // visitPHINode - Ensure that a PHI node is well formed.
252 void Verifier::visitPHINode(PHINode &PN) {
253 // Ensure that the PHI nodes are all grouped together at the top of the block.
254 // This can be tested by checking whether the instruction before this is
255 // either nonexistant (because this is begin()) or is a PHI node. If not,
256 // then there is some other instruction before a PHI.
257 Assert2(PN.getPrev() == 0 || isa<PHINode>(PN.getPrev()),
258 "PHI nodes not grouped at top of basic block!",
259 &PN, PN.getParent());
261 std::vector<BasicBlock*> Preds(pred_begin(PN.getParent()),
262 pred_end(PN.getParent()));
263 // Loop over all of the incoming values, make sure that there are
264 // predecessors for each one...
266 for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
267 // Make sure all of the incoming values are the right types...
268 Assert2(PN.getType() == PN.getIncomingValue(i)->getType(),
269 "PHI node argument type does not agree with PHI node type!",
270 &PN, PN.getIncomingValue(i));
272 BasicBlock *BB = PN.getIncomingBlock(i);
273 std::vector<BasicBlock*>::iterator PI =
274 find(Preds.begin(), Preds.end(), BB);
275 Assert2(PI != Preds.end(), "PHI node has entry for basic block that"
276 " is not a predecessor!", &PN, BB);
280 // There should be no entries left in the predecessor list...
281 for (std::vector<BasicBlock*>::iterator I = Preds.begin(),
282 E = Preds.end(); I != E; ++I)
283 Assert2(0, "PHI node does not have entry for a predecessor basic block!",
286 // Now we go through and check to make sure that if there is more than one
287 // entry for a particular basic block in this PHI node, that the incoming
288 // values are all identical.
290 std::vector<std::pair<BasicBlock*, Value*> > Values;
291 Values.reserve(PN.getNumIncomingValues());
292 for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i)
293 Values.push_back(std::make_pair(PN.getIncomingBlock(i),
294 PN.getIncomingValue(i)));
296 // Sort the Values vector so that identical basic block entries are adjacent.
297 std::sort(Values.begin(), Values.end());
299 // Check for identical basic blocks with differing incoming values...
300 for (unsigned i = 1, e = PN.getNumIncomingValues(); i < e; ++i)
301 Assert4(Values[i].first != Values[i-1].first ||
302 Values[i].second == Values[i-1].second,
303 "PHI node has multiple entries for the same basic block with "
304 "different incoming values!", &PN, Values[i].first,
305 Values[i].second, Values[i-1].second);
307 visitInstruction(PN);
310 void Verifier::visitCallInst(CallInst &CI) {
311 Assert1(isa<PointerType>(CI.getOperand(0)->getType()),
312 "Called function must be a pointer!", &CI);
313 const PointerType *FPTy = cast<PointerType>(CI.getOperand(0)->getType());
314 Assert1(isa<FunctionType>(FPTy->getElementType()),
315 "Called function is not pointer to function type!", &CI);
317 const FunctionType *FTy = cast<FunctionType>(FPTy->getElementType());
319 // Verify that the correct number of arguments are being passed
321 Assert1(CI.getNumOperands()-1 >= FTy->getNumParams(),
322 "Called function requires more parameters than were provided!",&CI);
324 Assert1(CI.getNumOperands()-1 == FTy->getNumParams(),
325 "Incorrect number of arguments passed to called function!", &CI);
327 // Verify that all arguments to the call match the function type...
328 for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
329 Assert2(CI.getOperand(i+1)->getType() == FTy->getParamType(i),
330 "Call parameter type does not match function signature!",
331 CI.getOperand(i+1), FTy->getParamType(i));
333 visitInstruction(CI);
336 // visitBinaryOperator - Check that both arguments to the binary operator are
339 void Verifier::visitBinaryOperator(BinaryOperator &B) {
340 Assert1(B.getOperand(0)->getType() == B.getOperand(1)->getType(),
341 "Both operands to a binary operator are not of the same type!", &B);
343 // Check that logical operators are only used with integral operands.
344 if (B.getOpcode() == Instruction::And || B.getOpcode() == Instruction::Or ||
345 B.getOpcode() == Instruction::Xor) {
346 Assert1(B.getType()->isIntegral(),
347 "Logical operators only work with integral types!", &B);
348 Assert1(B.getType() == B.getOperand(0)->getType(),
349 "Logical operators must have same type for operands and result!",
351 } else if (isa<SetCondInst>(B)) {
352 // Check that setcc instructions return bool
353 Assert1(B.getType() == Type::BoolTy,
354 "setcc instructions must return boolean values!", &B);
356 // Arithmetic operators only work on integer or fp values
357 Assert1(B.getType() == B.getOperand(0)->getType(),
358 "Arithmetic operators must have same type for operands and result!",
360 Assert1(B.getType()->isInteger() || B.getType()->isFloatingPoint(),
361 "Arithmetic operators must have integer or fp type!", &B);
367 void Verifier::visitShiftInst(ShiftInst &SI) {
368 Assert1(SI.getType()->isInteger(),
369 "Shift must return an integer result!", &SI);
370 Assert1(SI.getType() == SI.getOperand(0)->getType(),
371 "Shift return type must be same as first operand!", &SI);
372 Assert1(SI.getOperand(1)->getType() == Type::UByteTy,
373 "Second operand to shift must be ubyte type!", &SI);
374 visitInstruction(SI);
379 void Verifier::visitGetElementPtrInst(GetElementPtrInst &GEP) {
381 GetElementPtrInst::getIndexedType(GEP.getOperand(0)->getType(),
382 std::vector<Value*>(GEP.idx_begin(), GEP.idx_end()), true);
383 Assert1(ElTy, "Invalid indices for GEP pointer type!", &GEP);
384 Assert2(PointerType::get(ElTy) == GEP.getType(),
385 "GEP is not of right type for indices!", &GEP, ElTy);
386 visitInstruction(GEP);
389 void Verifier::visitLoadInst(LoadInst &LI) {
391 cast<PointerType>(LI.getOperand(0)->getType())->getElementType();
392 Assert2(ElTy == LI.getType(),
393 "Load is not of right type for indices!", &LI, ElTy);
394 visitInstruction(LI);
397 void Verifier::visitStoreInst(StoreInst &SI) {
399 cast<PointerType>(SI.getOperand(1)->getType())->getElementType();
400 Assert2(ElTy == SI.getOperand(0)->getType(),
401 "Stored value is not of right type for indices!", &SI, ElTy);
402 visitInstruction(SI);
406 // verifyInstruction - Verify that an instruction is well formed.
408 void Verifier::visitInstruction(Instruction &I) {
409 BasicBlock *BB = I.getParent();
410 Assert1(BB, "Instruction not embedded in basic block!", &I);
412 // Check that all uses of the instruction, if they are instructions
413 // themselves, actually have parent basic blocks. If the use is not an
414 // instruction, it is an error!
416 for (User::use_iterator UI = I.use_begin(), UE = I.use_end();
418 Assert1(isa<Instruction>(*UI), "Use of instruction is not an instruction!",
420 Instruction *Used = cast<Instruction>(*UI);
421 Assert2(Used->getParent() != 0, "Instruction referencing instruction not"
422 " embeded in a basic block!", &I, Used);
425 if (!isa<PHINode>(I)) { // Check that non-phi nodes are not self referential
426 for (Value::use_iterator UI = I.use_begin(), UE = I.use_end();
428 Assert1(*UI != (User*)&I,
429 "Only PHI nodes may reference their own value!", &I);
432 // Check that void typed values don't have names
433 Assert1(I.getType() != Type::VoidTy || !I.hasName(),
434 "Instruction has a name, but provides a void value!", &I);
436 // Check that a definition dominates all of its uses.
438 for (User::use_iterator UI = I.use_begin(), UE = I.use_end();
440 Instruction *Use = cast<Instruction>(*UI);
442 // PHI nodes are more difficult than other nodes because they actually
443 // "use" the value in the predecessor basic blocks they correspond to.
444 if (PHINode *PN = dyn_cast<PHINode>(Use)) {
445 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
446 if (&I == PN->getIncomingValue(i)) {
447 // Make sure that I dominates the end of pred(i)
448 BasicBlock *Pred = PN->getIncomingBlock(i);
450 // Use must be dominated by by definition unless use is unreachable!
451 Assert2(DS->dominates(BB, Pred) ||
452 !DS->dominates(&BB->getParent()->getEntryNode(), Pred),
453 "Instruction does not dominate all uses!",
458 // Use must be dominated by by definition unless use is unreachable!
459 Assert2(DS->dominates(&I, Use) ||
460 !DS->dominates(&BB->getParent()->getEntryNode(),Use->getParent()),
461 "Instruction does not dominate all uses!", &I, Use);
467 //===----------------------------------------------------------------------===//
468 // Implement the public interfaces to this file...
469 //===----------------------------------------------------------------------===//
471 Pass *createVerifierPass() {
472 return new Verifier();
476 // verifyFunction - Create
477 bool verifyFunction(const Function &f) {
478 Function &F = (Function&)f;
479 assert(!F.isExternal() && "Cannot verify external functions");
482 DS.doInitialization(*F.getParent());
488 DS.doFinalization(*F.getParent());
493 // verifyModule - Check a module for errors, printing messages on stderr.
494 // Return true if the module is corrupt.
496 bool verifyModule(const Module &M) {
498 Verifier *V = new Verifier();