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"
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());
73 bool runOnFunction(Function &F) {
74 // Get dominator information if we are being run by PassManager
75 if (RealPass) DS = &getAnalysis<DominatorSet>();
80 bool doFinalization(Module &M) {
81 // Scan through, checking all of the external function's linkage now...
82 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
83 if (I->isExternal() && I->hasInternalLinkage())
84 CheckFailed("Function Declaration has Internal Linkage!", I);
86 if (Broken && AbortBroken) {
87 std::cerr << "Broken module found, compilation aborted!\n";
93 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
96 AU.addRequired<DominatorSet>();
99 // Verification methods...
100 void verifySymbolTable(SymbolTable *ST);
101 void visitFunction(Function &F);
102 void visitBasicBlock(BasicBlock &BB);
103 void visitPHINode(PHINode &PN);
104 void visitBinaryOperator(BinaryOperator &B);
105 void visitShiftInst(ShiftInst &SI);
106 void visitCallInst(CallInst &CI);
107 void visitGetElementPtrInst(GetElementPtrInst &GEP);
108 void visitLoadInst(LoadInst &LI);
109 void visitStoreInst(StoreInst &SI);
110 void visitInstruction(Instruction &I);
111 void visitTerminatorInst(TerminatorInst &I);
112 void visitReturnInst(ReturnInst &RI);
114 // CheckFailed - A check failed, so print out the condition and the message
115 // that failed. This provides a nice place to put a breakpoint if you want
116 // to see why something is not correct.
118 inline void CheckFailed(const std::string &Message,
119 const Value *V1 = 0, const Value *V2 = 0,
120 const Value *V3 = 0, const Value *V4 = 0) {
121 std::cerr << Message << "\n";
122 if (V1) std::cerr << *V1 << "\n";
123 if (V2) std::cerr << *V2 << "\n";
124 if (V3) std::cerr << *V3 << "\n";
125 if (V4) std::cerr << *V4 << "\n";
130 RegisterPass<Verifier> X("verify", "Module Verifier");
133 // Assert - We know that cond should be true, if not print an error message.
134 #define Assert(C, M) \
135 do { if (!(C)) { CheckFailed(M); return; } } while (0)
136 #define Assert1(C, M, V1) \
137 do { if (!(C)) { CheckFailed(M, V1); return; } } while (0)
138 #define Assert2(C, M, V1, V2) \
139 do { if (!(C)) { CheckFailed(M, V1, V2); return; } } while (0)
140 #define Assert3(C, M, V1, V2, V3) \
141 do { if (!(C)) { CheckFailed(M, V1, V2, V3); return; } } while (0)
142 #define Assert4(C, M, V1, V2, V3, V4) \
143 do { if (!(C)) { CheckFailed(M, V1, V2, V3, V4); return; } } while (0)
146 // verifySymbolTable - Verify that a function or module symbol table is ok
148 void Verifier::verifySymbolTable(SymbolTable *ST) {
149 if (ST == 0) return; // No symbol table to process
151 // Loop over all of the types in the symbol table...
152 for (SymbolTable::iterator TI = ST->begin(), TE = ST->end(); TI != TE; ++TI)
153 for (SymbolTable::type_iterator I = TI->second.begin(),
154 E = TI->second.end(); I != E; ++I) {
155 Value *V = I->second;
157 // Check that there are no void typed values in the symbol table. Values
158 // with a void type cannot be put into symbol tables because they cannot
160 Assert1(V->getType() != Type::VoidTy,
161 "Values with void type are not allowed to have names!", V);
166 // visitFunction - Verify that a function is ok.
168 void Verifier::visitFunction(Function &F) {
169 if (F.isExternal()) return;
171 verifySymbolTable(F.getSymbolTable());
173 // Check function arguments...
174 const FunctionType *FT = F.getFunctionType();
175 unsigned NumArgs = F.getArgumentList().size();
177 Assert2(!FT->isVarArg(), "Cannot define varargs functions in LLVM!", &F, FT);
178 Assert2(FT->getParamTypes().size() == NumArgs,
179 "# formal arguments must match # of arguments for function type!",
182 // Check that the argument values match the function type for this function...
183 if (FT->getParamTypes().size() == NumArgs) {
185 for (Function::aiterator I = F.abegin(), E = F.aend(); I != E; ++I, ++i)
186 Assert2(I->getType() == FT->getParamType(i),
187 "Argument value does not match function argument type!",
188 I, FT->getParamType(i));
191 // Check the entry node
192 BasicBlock *Entry = &F.getEntryNode();
193 Assert1(pred_begin(Entry) == pred_end(Entry),
194 "Entry block to function must not have predecessors!", Entry);
198 // verifyBasicBlock - Verify that a basic block is well formed...
200 void Verifier::visitBasicBlock(BasicBlock &BB) {
201 // Ensure that basic blocks have terminators!
202 Assert1(BB.getTerminator(), "Basic Block does not have terminator!", &BB);
205 void Verifier::visitTerminatorInst(TerminatorInst &I) {
206 // Ensure that terminators only exist at the end of the basic block.
207 Assert1(&I == I.getParent()->getTerminator(),
208 "Terminator found in the middle of a basic block!", I.getParent());
212 void Verifier::visitReturnInst(ReturnInst &RI) {
213 Function *F = RI.getParent()->getParent();
214 if (RI.getNumOperands() == 0)
215 Assert1(F->getReturnType() == Type::VoidTy,
216 "Function returns no value, but ret instruction found that does!",
219 Assert2(F->getReturnType() == RI.getOperand(0)->getType(),
220 "Function return type does not match operand "
221 "type of return inst!", &RI, F->getReturnType());
223 // Check to make sure that the return value has neccesary properties for
225 visitTerminatorInst(RI);
229 // visitPHINode - Ensure that a PHI node is well formed.
230 void Verifier::visitPHINode(PHINode &PN) {
231 // Ensure that the PHI nodes are all grouped together at the top of the block.
232 // This can be tested by checking whether the instruction before this is
233 // either nonexistant (because this is begin()) or is a PHI node. If not,
234 // then there is some other instruction before a PHI.
235 Assert2(PN.getPrev() == 0 || isa<PHINode>(PN.getPrev()),
236 "PHI nodes not grouped at top of basic block!",
237 &PN, PN.getParent());
239 std::vector<BasicBlock*> Preds(pred_begin(PN.getParent()),
240 pred_end(PN.getParent()));
241 // Loop over all of the incoming values, make sure that there are
242 // predecessors for each one...
244 for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
245 // Make sure all of the incoming values are the right types...
246 Assert2(PN.getType() == PN.getIncomingValue(i)->getType(),
247 "PHI node argument type does not agree with PHI node type!",
248 &PN, PN.getIncomingValue(i));
250 BasicBlock *BB = PN.getIncomingBlock(i);
251 std::vector<BasicBlock*>::iterator PI =
252 find(Preds.begin(), Preds.end(), BB);
253 Assert2(PI != Preds.end(), "PHI node has entry for basic block that"
254 " is not a predecessor!", &PN, BB);
258 // There should be no entries left in the predecessor list...
259 for (std::vector<BasicBlock*>::iterator I = Preds.begin(),
260 E = Preds.end(); I != E; ++I)
261 Assert2(0, "PHI node does not have entry for a predecessor basic block!",
264 // Now we go through and check to make sure that if there is more than one
265 // entry for a particular basic block in this PHI node, that the incoming
266 // values are all identical.
268 std::vector<std::pair<BasicBlock*, Value*> > Values;
269 Values.reserve(PN.getNumIncomingValues());
270 for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i)
271 Values.push_back(std::make_pair(PN.getIncomingBlock(i),
272 PN.getIncomingValue(i)));
274 // Sort the Values vector so that identical basic block entries are adjacent.
275 std::sort(Values.begin(), Values.end());
277 // Check for identical basic blocks with differing incoming values...
278 for (unsigned i = 1, e = PN.getNumIncomingValues(); i < e; ++i)
279 Assert4(Values[i].first != Values[i-1].first ||
280 Values[i].second == Values[i-1].second,
281 "PHI node has multiple entries for the same basic block with "
282 "different incoming values!", &PN, Values[i].first,
283 Values[i].second, Values[i-1].second);
285 visitInstruction(PN);
288 void Verifier::visitCallInst(CallInst &CI) {
289 Assert1(isa<PointerType>(CI.getOperand(0)->getType()),
290 "Called function must be a pointer!", &CI);
291 const PointerType *FPTy = cast<PointerType>(CI.getOperand(0)->getType());
292 Assert1(isa<FunctionType>(FPTy->getElementType()),
293 "Called function is not pointer to function type!", &CI);
295 const FunctionType *FTy = cast<FunctionType>(FPTy->getElementType());
297 // Verify that the correct number of arguments are being passed
299 Assert1(CI.getNumOperands()-1 >= FTy->getNumParams(),
300 "Called function requires more parameters than were provided!",&CI);
302 Assert1(CI.getNumOperands()-1 == FTy->getNumParams(),
303 "Incorrect number of arguments passed to called function!", &CI);
305 // Verify that all arguments to the call match the function type...
306 for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
307 Assert2(CI.getOperand(i+1)->getType() == FTy->getParamType(i),
308 "Call parameter type does not match function signature!",
309 CI.getOperand(i+1), FTy->getParamType(i));
311 visitInstruction(CI);
314 // visitBinaryOperator - Check that both arguments to the binary operator are
317 void Verifier::visitBinaryOperator(BinaryOperator &B) {
318 Assert1(B.getOperand(0)->getType() == B.getOperand(1)->getType(),
319 "Both operands to a binary operator are not of the same type!", &B);
321 // Check that logical operators are only used with integral operands.
322 if (B.getOpcode() == Instruction::And || B.getOpcode() == Instruction::Or ||
323 B.getOpcode() == Instruction::Xor) {
324 Assert1(B.getType()->isIntegral(),
325 "Logical operators only work with integral types!", &B);
326 Assert1(B.getType() == B.getOperand(0)->getType(),
327 "Logical operators must have same type for operands and result!",
329 } else if (isa<SetCondInst>(B)) {
330 // Check that setcc instructions return bool
331 Assert1(B.getType() == Type::BoolTy,
332 "setcc instructions must return boolean values!", &B);
334 // Arithmetic operators only work on integer or fp values
335 Assert1(B.getType() == B.getOperand(0)->getType(),
336 "Arithmetic operators must have same type for operands and result!",
338 Assert1(B.getType()->isInteger() || B.getType()->isFloatingPoint(),
339 "Arithmetic operators must have integer or fp type!", &B);
345 void Verifier::visitShiftInst(ShiftInst &SI) {
346 Assert1(SI.getType()->isInteger(),
347 "Shift must return an integer result!", &SI);
348 Assert1(SI.getType() == SI.getOperand(0)->getType(),
349 "Shift return type must be same as first operand!", &SI);
350 Assert1(SI.getOperand(1)->getType() == Type::UByteTy,
351 "Second operand to shift must be ubyte type!", &SI);
352 visitInstruction(SI);
357 void Verifier::visitGetElementPtrInst(GetElementPtrInst &GEP) {
359 GetElementPtrInst::getIndexedType(GEP.getOperand(0)->getType(),
360 std::vector<Value*>(GEP.idx_begin(), GEP.idx_end()), true);
361 Assert1(ElTy, "Invalid indices for GEP pointer type!", &GEP);
362 Assert2(PointerType::get(ElTy) == GEP.getType(),
363 "GEP is not of right type for indices!", &GEP, ElTy);
364 visitInstruction(GEP);
367 void Verifier::visitLoadInst(LoadInst &LI) {
369 cast<PointerType>(LI.getOperand(0)->getType())->getElementType();
370 Assert2(ElTy == LI.getType(),
371 "Load is not of right type for indices!", &LI, ElTy);
372 visitInstruction(LI);
375 void Verifier::visitStoreInst(StoreInst &SI) {
377 cast<PointerType>(SI.getOperand(1)->getType())->getElementType();
378 Assert2(ElTy == SI.getOperand(0)->getType(),
379 "Stored value is not of right type for indices!", &SI, ElTy);
380 visitInstruction(SI);
384 // verifyInstruction - Verify that an instruction is well formed.
386 void Verifier::visitInstruction(Instruction &I) {
387 BasicBlock *BB = I.getParent();
388 Assert1(BB, "Instruction not embedded in basic block!", &I);
390 // Check that all uses of the instruction, if they are instructions
391 // themselves, actually have parent basic blocks. If the use is not an
392 // instruction, it is an error!
394 for (User::use_iterator UI = I.use_begin(), UE = I.use_end();
396 Assert1(isa<Instruction>(*UI), "Use of instruction is not an instruction!",
398 Instruction *Used = cast<Instruction>(*UI);
399 Assert2(Used->getParent() != 0, "Instruction referencing instruction not"
400 " embeded in a basic block!", &I, Used);
403 if (!isa<PHINode>(I)) { // Check that non-phi nodes are not self referential
404 for (Value::use_iterator UI = I.use_begin(), UE = I.use_end();
406 Assert1(*UI != (User*)&I,
407 "Only PHI nodes may reference their own value!", &I);
410 // Check that void typed values don't have names
411 Assert1(I.getType() != Type::VoidTy || !I.hasName(),
412 "Instruction has a name, but provides a void value!", &I);
414 // Check that a definition dominates all of its uses.
416 for (User::use_iterator UI = I.use_begin(), UE = I.use_end();
418 Instruction *Use = cast<Instruction>(*UI);
420 // PHI nodes are more difficult than other nodes because they actually
421 // "use" the value in the predecessor basic blocks they correspond to.
422 if (PHINode *PN = dyn_cast<PHINode>(Use)) {
423 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
424 if (&I == PN->getIncomingValue(i)) {
425 // Make sure that I dominates the end of pred(i)
426 BasicBlock *Pred = PN->getIncomingBlock(i);
428 // Use must be dominated by by definition unless use is unreachable!
429 Assert2(DS->dominates(BB, Pred) ||
430 !DS->dominates(&BB->getParent()->getEntryNode(), Pred),
431 "Instruction does not dominate all uses!",
436 // Use must be dominated by by definition unless use is unreachable!
437 Assert2(DS->dominates(&I, Use) ||
438 !DS->dominates(&BB->getParent()->getEntryNode(),Use->getParent()),
439 "Instruction does not dominate all uses!", &I, Use);
445 //===----------------------------------------------------------------------===//
446 // Implement the public interfaces to this file...
447 //===----------------------------------------------------------------------===//
449 Pass *createVerifierPass() {
450 return new Verifier();
454 // verifyFunction - Create
455 bool verifyFunction(const Function &f) {
456 Function &F = (Function&)f;
457 assert(!F.isExternal() && "Cannot verify external functions");
460 DS.doInitialization(*F.getParent());
466 DS.doFinalization(*F.getParent());
471 // verifyModule - Check a module for errors, printing messages on stderr.
472 // Return true if the module is corrupt.
474 bool verifyModule(const Module &M) {
476 Verifier *V = new Verifier();