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 // . There are no duplicated names in a symbol table... ie there !exist a val
10 // with the same name as something in the symbol table, but with a different
11 // address as what is in the symbol table...
12 // * Both of a binary operator's parameters are the same type
13 // * Verify that the indices of mem access instructions match other operands
14 // . Verify that arithmetic and other things are only performed on first class
15 // types. No adding structures or arrays.
16 // . All of the constants in a switch statement are of the correct type
17 // . The code is in valid SSA form
18 // . It should be illegal to put a label into any other type (like a structure)
19 // or to return one. [except constant arrays!]
20 // * Only phi nodes can be self referential: 'add int %0, %0 ; <int>:0' is bad
21 // * PHI nodes must have an entry for each predecessor, with no extras.
22 // * PHI nodes must be the first thing in a basic block, all grouped together
23 // * All basic blocks should only end with terminator insts, not contain them
24 // * The entry node to a function must not have predecessors
25 // * All Instructions must be embeded into a basic block
26 // . Verify that none of the Value getType()'s are null.
27 // . Function's cannot take a void typed parameter
28 // * Verify that a function's argument list agrees with it's declared type.
29 // . Verify that arrays and structures have fixed elements: No unsized arrays.
30 // * It is illegal to specify a name for a void value.
31 // * It is illegal to have a internal function that is just a declaration
32 // * It is illegal to have a ret instruction that returns a value that does not
33 // agree with the function return value type.
34 // * Function call argument types match the function prototype
35 // * All other things that are tested by asserts spread about the code...
37 //===----------------------------------------------------------------------===//
39 #include "llvm/Analysis/Verifier.h"
40 #include "llvm/Pass.h"
41 #include "llvm/Module.h"
42 #include "llvm/DerivedTypes.h"
43 #include "llvm/iPHINode.h"
44 #include "llvm/iTerminators.h"
45 #include "llvm/iOther.h"
46 #include "llvm/iMemory.h"
47 #include "llvm/SymbolTable.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> {
58 Verifier() : Broken(false) {}
60 virtual const char *getPassName() const { return "Module Verifier"; }
62 bool doInitialization(Module &M) {
63 verifySymbolTable(M.getSymbolTable());
67 bool runOnFunction(Function &F) {
72 bool doFinalization(Module &M) {
73 // Scan through, checking all of the external function's linkage now...
74 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
75 if (I->isExternal() && I->hasInternalLinkage())
76 CheckFailed("Function Declaration has Internal Linkage!", I);
79 cerr << "Broken module found, compilation aborted!\n";
85 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
89 // Verification methods...
90 void verifySymbolTable(SymbolTable *ST);
91 void visitFunction(Function &F);
92 void visitBasicBlock(BasicBlock &BB);
93 void visitPHINode(PHINode &PN);
94 void visitBinaryOperator(BinaryOperator &B);
95 void visitCallInst(CallInst &CI);
96 void visitGetElementPtrInst(GetElementPtrInst &GEP);
97 void visitLoadInst(LoadInst &LI);
98 void visitStoreInst(StoreInst &SI);
99 void visitInstruction(Instruction &I);
100 void visitTerminatorInst(TerminatorInst &I);
101 void visitReturnInst(ReturnInst &RI);
103 // CheckFailed - A check failed, so print out the condition and the message
104 // that failed. This provides a nice place to put a breakpoint if you want
105 // to see why something is not correct.
107 inline void CheckFailed(const std::string &Message,
108 const Value *V1 = 0, const Value *V2 = 0,
109 const Value *V3 = 0, const Value *V4 = 0) {
110 std::cerr << Message << "\n";
111 if (V1) std::cerr << *V1 << "\n";
112 if (V2) std::cerr << *V2 << "\n";
113 if (V3) std::cerr << *V3 << "\n";
114 if (V4) std::cerr << *V4 << "\n";
120 // Assert - We know that cond should be true, if not print an error message.
121 #define Assert(C, M) \
122 do { if (!(C)) { CheckFailed(M); return; } } while (0)
123 #define Assert1(C, M, V1) \
124 do { if (!(C)) { CheckFailed(M, V1); return; } } while (0)
125 #define Assert2(C, M, V1, V2) \
126 do { if (!(C)) { CheckFailed(M, V1, V2); return; } } while (0)
127 #define Assert3(C, M, V1, V2, V3) \
128 do { if (!(C)) { CheckFailed(M, V1, V2, V3); return; } } while (0)
129 #define Assert4(C, M, V1, V2, V3, V4) \
130 do { if (!(C)) { CheckFailed(M, V1, V2, V3, V4); return; } } while (0)
133 // verifySymbolTable - Verify that a function or module symbol table is ok
135 void Verifier::verifySymbolTable(SymbolTable *ST) {
136 if (ST == 0) return; // No symbol table to process
138 // Loop over all of the types in the symbol table...
139 for (SymbolTable::iterator TI = ST->begin(), TE = ST->end(); TI != TE; ++TI)
140 for (SymbolTable::type_iterator I = TI->second.begin(),
141 E = TI->second.end(); I != E; ++I) {
142 Value *V = I->second;
144 // Check that there are no void typed values in the symbol table. Values
145 // with a void type cannot be put into symbol tables because they cannot
147 Assert1(V->getType() != Type::VoidTy,
148 "Values with void type are not allowed to have names!", V);
153 // visitFunction - Verify that a function is ok.
155 void Verifier::visitFunction(Function &F) {
156 if (F.isExternal()) return;
158 verifySymbolTable(F.getSymbolTable());
160 // Check function arguments...
161 const FunctionType *FT = F.getFunctionType();
162 unsigned NumArgs = F.getArgumentList().size();
164 Assert2(!FT->isVarArg(), "Cannot define varargs functions in LLVM!", &F, FT);
165 Assert2(FT->getParamTypes().size() == NumArgs,
166 "# formal arguments must match # of arguments for function type!",
169 // Check that the argument values match the function type for this function...
170 if (FT->getParamTypes().size() == NumArgs) {
172 for (Function::aiterator I = F.abegin(), E = F.aend(); I != E; ++I, ++i)
173 Assert2(I->getType() == FT->getParamType(i),
174 "Argument value does not match function argument type!",
175 I, FT->getParamType(i));
178 // Check the entry node
179 BasicBlock *Entry = &F.getEntryNode();
180 Assert1(pred_begin(Entry) == pred_end(Entry),
181 "Entry block to function must not have predecessors!", Entry);
185 // verifyBasicBlock - Verify that a basic block is well formed...
187 void Verifier::visitBasicBlock(BasicBlock &BB) {
188 // Ensure that basic blocks have terminators!
189 Assert1(BB.getTerminator(), "Basic Block does not have terminator!", &BB);
192 void Verifier::visitTerminatorInst(TerminatorInst &I) {
193 // Ensure that terminators only exist at the end of the basic block.
194 Assert1(&I == I.getParent()->getTerminator(),
195 "Terminator found in the middle of a basic block!", I.getParent());
198 void Verifier::visitReturnInst(ReturnInst &RI) {
199 Function *F = RI.getParent()->getParent();
200 if (RI.getNumOperands() == 0)
201 Assert1(F->getReturnType() == Type::VoidTy,
202 "Function returns no value, but ret instruction found that does!",
205 Assert2(F->getReturnType() == RI.getOperand(0)->getType(),
206 "Function return type does not match operand "
207 "type of return inst!", &RI, F->getReturnType());
209 // Check to make sure that the return value has neccesary properties for
211 visitTerminatorInst(RI);
215 // visitPHINode - Ensure that a PHI node is well formed.
216 void Verifier::visitPHINode(PHINode &PN) {
217 // Ensure that the PHI nodes are all grouped together at the top of the block.
218 // This can be tested by checking whether the instruction before this is
219 // either nonexistant (because this is begin()) or is a PHI node. If not,
220 // then there is some other instruction before a PHI.
221 Assert2(PN.getPrev() == 0 || isa<PHINode>(PN.getPrev()),
222 "PHI nodes not grouped at top of basic block!",
223 &PN, PN.getParent());
225 std::vector<BasicBlock*> Preds(pred_begin(PN.getParent()),
226 pred_end(PN.getParent()));
227 // Loop over all of the incoming values, make sure that there are
228 // predecessors for each one...
230 for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
231 // Make sure all of the incoming values are the right types...
232 Assert2(PN.getType() == PN.getIncomingValue(i)->getType(),
233 "PHI node argument type does not agree with PHI node type!",
234 &PN, PN.getIncomingValue(i));
236 BasicBlock *BB = PN.getIncomingBlock(i);
237 std::vector<BasicBlock*>::iterator PI =
238 find(Preds.begin(), Preds.end(), BB);
239 Assert2(PI != Preds.end(), "PHI node has entry for basic block that"
240 " is not a predecessor!", &PN, BB);
244 // There should be no entries left in the predecessor list...
245 for (std::vector<BasicBlock*>::iterator I = Preds.begin(),
246 E = Preds.end(); I != E; ++I)
247 Assert2(0, "PHI node does not have entry for a predecessor basic block!",
250 // Now we go through and check to make sure that if there is more than one
251 // entry for a particular basic block in this PHI node, that the incoming
252 // values are all identical.
254 std::vector<std::pair<BasicBlock*, Value*> > Values;
255 Values.reserve(PN.getNumIncomingValues());
256 for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i)
257 Values.push_back(std::make_pair(PN.getIncomingBlock(i),
258 PN.getIncomingValue(i)));
260 // Sort the Values vector so that identical basic block entries are adjacent.
261 std::sort(Values.begin(), Values.end());
263 // Check for identical basic blocks with differing incoming values...
264 for (unsigned i = 1, e = PN.getNumIncomingValues(); i < e; ++i)
265 Assert4(Values[i].first != Values[i-1].first ||
266 Values[i].second == Values[i-1].second,
267 "PHI node has multiple entries for the same basic block with "
268 "different incoming values!", &PN, Values[i].first,
269 Values[i].second, Values[i-1].second);
271 visitInstruction(PN);
274 void Verifier::visitCallInst(CallInst &CI) {
275 Assert1(isa<PointerType>(CI.getOperand(0)->getType()),
276 "Called function must be a pointer!", &CI);
277 const PointerType *FPTy = cast<PointerType>(CI.getOperand(0)->getType());
278 Assert1(isa<FunctionType>(FPTy->getElementType()),
279 "Called function is not pointer to function type!", &CI);
281 const FunctionType *FTy = cast<FunctionType>(FPTy->getElementType());
283 // Verify that the correct number of arguments are being passed
285 Assert1(CI.getNumOperands()-1 >= FTy->getNumParams(),
286 "Called function requires more parameters than were provided!",&CI);
288 Assert1(CI.getNumOperands()-1 == FTy->getNumParams(),
289 "Incorrect number of arguments passed to called function!", &CI);
291 // Verify that all arguments to the call match the function type...
292 for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
293 Assert2(CI.getOperand(i+1)->getType() == FTy->getParamType(i),
294 "Call parameter type does not match function signature!",
295 CI.getOperand(i+1), FTy->getParamType(i));
298 // visitBinaryOperator - Check that both arguments to the binary operator are
301 void Verifier::visitBinaryOperator(BinaryOperator &B) {
302 Assert2(B.getOperand(0)->getType() == B.getOperand(1)->getType(),
303 "Both operands to a binary operator are not of the same type!",
304 B.getOperand(0), B.getOperand(1));
309 void Verifier::visitGetElementPtrInst(GetElementPtrInst &GEP) {
310 const Type *ElTy = MemAccessInst::getIndexedType(GEP.getOperand(0)->getType(),
311 GEP.copyIndices(), true);
312 Assert1(ElTy, "Invalid indices for GEP pointer type!", &GEP);
313 Assert2(PointerType::get(ElTy) == GEP.getType(),
314 "GEP is not of right type for indices!", &GEP, ElTy);
315 visitInstruction(GEP);
318 void Verifier::visitLoadInst(LoadInst &LI) {
319 const Type *ElTy = LoadInst::getIndexedType(LI.getOperand(0)->getType(),
321 Assert1(ElTy, "Invalid indices for load pointer type!", &LI);
322 Assert2(ElTy == LI.getType(),
323 "Load is not of right type for indices!", &LI, ElTy);
324 visitInstruction(LI);
327 void Verifier::visitStoreInst(StoreInst &SI) {
328 const Type *ElTy = StoreInst::getIndexedType(SI.getOperand(1)->getType(),
330 Assert1(ElTy, "Invalid indices for store pointer type!", &SI);
331 Assert2(ElTy == SI.getOperand(0)->getType(),
332 "Stored value is not of right type for indices!", &SI, ElTy);
333 visitInstruction(SI);
337 // verifyInstruction - Verify that a non-terminator instruction is well formed.
339 void Verifier::visitInstruction(Instruction &I) {
340 Assert1(I.getParent(), "Instruction not embedded in basic block!", &I);
342 // Check that all uses of the instruction, if they are instructions
343 // themselves, actually have parent basic blocks. If the use is not an
344 // instruction, it is an error!
346 for (User::use_iterator UI = I.use_begin(), UE = I.use_end();
348 Assert1(isa<Instruction>(*UI), "Use of instruction is not an instruction!",
350 Instruction *Used = cast<Instruction>(*UI);
351 Assert2(Used->getParent() != 0, "Instruction referencing instruction not"
352 " embeded in a basic block!", &I, Used);
355 if (!isa<PHINode>(I)) { // Check that non-phi nodes are not self referential
356 for (Value::use_iterator UI = I.use_begin(), UE = I.use_end();
358 Assert1(*UI != (User*)&I,
359 "Only PHI nodes may reference their own value!", &I);
362 Assert1(I.getType() != Type::VoidTy || !I.hasName(),
363 "Instruction has a name, but provides a void value!", &I);
367 //===----------------------------------------------------------------------===//
368 // Implement the public interfaces to this file...
369 //===----------------------------------------------------------------------===//
371 Pass *createVerifierPass() {
372 return new Verifier();
375 bool verifyFunction(const Function &F) {
377 V.visit((Function&)F);
381 // verifyModule - Check a module for errors, printing messages on stderr.
382 // Return true if the module is corrupt.
384 bool verifyModule(const Module &M) {