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"
54 namespace { // Anonymous namespace for class
56 struct Verifier : public FunctionPass, InstVisitor<Verifier> {
59 Verifier() : Broken(false) {}
61 virtual const char *getPassName() const { return "Module Verifier"; }
63 bool doInitialization(Module &M) {
64 verifySymbolTable(M.getSymbolTable());
68 bool runOnFunction(Function &F) {
73 bool doFinalization(Module &M) {
74 // Scan through, checking all of the external function's linkage now...
75 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
76 if (I->isExternal() && I->hasInternalLinkage())
77 CheckFailed("Function Declaration has Internal Linkage!", I);
80 std::cerr << "Broken module found, compilation aborted!\n";
86 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
90 // Verification methods...
91 void verifySymbolTable(SymbolTable *ST);
92 void visitFunction(Function &F);
93 void visitBasicBlock(BasicBlock &BB);
94 void visitPHINode(PHINode &PN);
95 void visitBinaryOperator(BinaryOperator &B);
96 void visitCallInst(CallInst &CI);
97 void visitGetElementPtrInst(GetElementPtrInst &GEP);
98 void visitLoadInst(LoadInst &LI);
99 void visitStoreInst(StoreInst &SI);
100 void visitInstruction(Instruction &I);
101 void visitTerminatorInst(TerminatorInst &I);
102 void visitReturnInst(ReturnInst &RI);
104 // CheckFailed - A check failed, so print out the condition and the message
105 // that failed. This provides a nice place to put a breakpoint if you want
106 // to see why something is not correct.
108 inline void CheckFailed(const std::string &Message,
109 const Value *V1 = 0, const Value *V2 = 0,
110 const Value *V3 = 0, const Value *V4 = 0) {
111 std::cerr << Message << "\n";
112 if (V1) std::cerr << *V1 << "\n";
113 if (V2) std::cerr << *V2 << "\n";
114 if (V3) std::cerr << *V3 << "\n";
115 if (V4) std::cerr << *V4 << "\n";
121 // Assert - We know that cond should be true, if not print an error message.
122 #define Assert(C, M) \
123 do { if (!(C)) { CheckFailed(M); return; } } while (0)
124 #define Assert1(C, M, V1) \
125 do { if (!(C)) { CheckFailed(M, V1); return; } } while (0)
126 #define Assert2(C, M, V1, V2) \
127 do { if (!(C)) { CheckFailed(M, V1, V2); return; } } while (0)
128 #define Assert3(C, M, V1, V2, V3) \
129 do { if (!(C)) { CheckFailed(M, V1, V2, V3); return; } } while (0)
130 #define Assert4(C, M, V1, V2, V3, V4) \
131 do { if (!(C)) { CheckFailed(M, V1, V2, V3, V4); return; } } while (0)
134 // verifySymbolTable - Verify that a function or module symbol table is ok
136 void Verifier::verifySymbolTable(SymbolTable *ST) {
137 if (ST == 0) return; // No symbol table to process
139 // Loop over all of the types in the symbol table...
140 for (SymbolTable::iterator TI = ST->begin(), TE = ST->end(); TI != TE; ++TI)
141 for (SymbolTable::type_iterator I = TI->second.begin(),
142 E = TI->second.end(); I != E; ++I) {
143 Value *V = I->second;
145 // Check that there are no void typed values in the symbol table. Values
146 // with a void type cannot be put into symbol tables because they cannot
148 Assert1(V->getType() != Type::VoidTy,
149 "Values with void type are not allowed to have names!", V);
154 // visitFunction - Verify that a function is ok.
156 void Verifier::visitFunction(Function &F) {
157 if (F.isExternal()) return;
159 verifySymbolTable(F.getSymbolTable());
161 // Check function arguments...
162 const FunctionType *FT = F.getFunctionType();
163 unsigned NumArgs = F.getArgumentList().size();
165 Assert2(!FT->isVarArg(), "Cannot define varargs functions in LLVM!", &F, FT);
166 Assert2(FT->getParamTypes().size() == NumArgs,
167 "# formal arguments must match # of arguments for function type!",
170 // Check that the argument values match the function type for this function...
171 if (FT->getParamTypes().size() == NumArgs) {
173 for (Function::aiterator I = F.abegin(), E = F.aend(); I != E; ++I, ++i)
174 Assert2(I->getType() == FT->getParamType(i),
175 "Argument value does not match function argument type!",
176 I, FT->getParamType(i));
179 // Check the entry node
180 BasicBlock *Entry = &F.getEntryNode();
181 Assert1(pred_begin(Entry) == pred_end(Entry),
182 "Entry block to function must not have predecessors!", Entry);
186 // verifyBasicBlock - Verify that a basic block is well formed...
188 void Verifier::visitBasicBlock(BasicBlock &BB) {
189 // Ensure that basic blocks have terminators!
190 Assert1(BB.getTerminator(), "Basic Block does not have terminator!", &BB);
193 void Verifier::visitTerminatorInst(TerminatorInst &I) {
194 // Ensure that terminators only exist at the end of the basic block.
195 Assert1(&I == I.getParent()->getTerminator(),
196 "Terminator found in the middle of a basic block!", I.getParent());
199 void Verifier::visitReturnInst(ReturnInst &RI) {
200 Function *F = RI.getParent()->getParent();
201 if (RI.getNumOperands() == 0)
202 Assert1(F->getReturnType() == Type::VoidTy,
203 "Function returns no value, but ret instruction found that does!",
206 Assert2(F->getReturnType() == RI.getOperand(0)->getType(),
207 "Function return type does not match operand "
208 "type of return inst!", &RI, F->getReturnType());
210 // Check to make sure that the return value has neccesary properties for
212 visitTerminatorInst(RI);
216 // visitPHINode - Ensure that a PHI node is well formed.
217 void Verifier::visitPHINode(PHINode &PN) {
218 // Ensure that the PHI nodes are all grouped together at the top of the block.
219 // This can be tested by checking whether the instruction before this is
220 // either nonexistant (because this is begin()) or is a PHI node. If not,
221 // then there is some other instruction before a PHI.
222 Assert2(PN.getPrev() == 0 || isa<PHINode>(PN.getPrev()),
223 "PHI nodes not grouped at top of basic block!",
224 &PN, PN.getParent());
226 std::vector<BasicBlock*> Preds(pred_begin(PN.getParent()),
227 pred_end(PN.getParent()));
228 // Loop over all of the incoming values, make sure that there are
229 // predecessors for each one...
231 for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
232 // Make sure all of the incoming values are the right types...
233 Assert2(PN.getType() == PN.getIncomingValue(i)->getType(),
234 "PHI node argument type does not agree with PHI node type!",
235 &PN, PN.getIncomingValue(i));
237 BasicBlock *BB = PN.getIncomingBlock(i);
238 std::vector<BasicBlock*>::iterator PI =
239 find(Preds.begin(), Preds.end(), BB);
240 Assert2(PI != Preds.end(), "PHI node has entry for basic block that"
241 " is not a predecessor!", &PN, BB);
245 // There should be no entries left in the predecessor list...
246 for (std::vector<BasicBlock*>::iterator I = Preds.begin(),
247 E = Preds.end(); I != E; ++I)
248 Assert2(0, "PHI node does not have entry for a predecessor basic block!",
251 // Now we go through and check to make sure that if there is more than one
252 // entry for a particular basic block in this PHI node, that the incoming
253 // values are all identical.
255 std::vector<std::pair<BasicBlock*, Value*> > Values;
256 Values.reserve(PN.getNumIncomingValues());
257 for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i)
258 Values.push_back(std::make_pair(PN.getIncomingBlock(i),
259 PN.getIncomingValue(i)));
261 // Sort the Values vector so that identical basic block entries are adjacent.
262 std::sort(Values.begin(), Values.end());
264 // Check for identical basic blocks with differing incoming values...
265 for (unsigned i = 1, e = PN.getNumIncomingValues(); i < e; ++i)
266 Assert4(Values[i].first != Values[i-1].first ||
267 Values[i].second == Values[i-1].second,
268 "PHI node has multiple entries for the same basic block with "
269 "different incoming values!", &PN, Values[i].first,
270 Values[i].second, Values[i-1].second);
272 visitInstruction(PN);
275 void Verifier::visitCallInst(CallInst &CI) {
276 Assert1(isa<PointerType>(CI.getOperand(0)->getType()),
277 "Called function must be a pointer!", &CI);
278 const PointerType *FPTy = cast<PointerType>(CI.getOperand(0)->getType());
279 Assert1(isa<FunctionType>(FPTy->getElementType()),
280 "Called function is not pointer to function type!", &CI);
282 const FunctionType *FTy = cast<FunctionType>(FPTy->getElementType());
284 // Verify that the correct number of arguments are being passed
286 Assert1(CI.getNumOperands()-1 >= FTy->getNumParams(),
287 "Called function requires more parameters than were provided!",&CI);
289 Assert1(CI.getNumOperands()-1 == FTy->getNumParams(),
290 "Incorrect number of arguments passed to called function!", &CI);
292 // Verify that all arguments to the call match the function type...
293 for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
294 Assert2(CI.getOperand(i+1)->getType() == FTy->getParamType(i),
295 "Call parameter type does not match function signature!",
296 CI.getOperand(i+1), FTy->getParamType(i));
299 // visitBinaryOperator - Check that both arguments to the binary operator are
302 void Verifier::visitBinaryOperator(BinaryOperator &B) {
303 Assert2(B.getOperand(0)->getType() == B.getOperand(1)->getType(),
304 "Both operands to a binary operator are not of the same type!",
305 B.getOperand(0), B.getOperand(1));
310 void Verifier::visitGetElementPtrInst(GetElementPtrInst &GEP) {
311 const Type *ElTy = MemAccessInst::getIndexedType(GEP.getOperand(0)->getType(),
312 GEP.copyIndices(), true);
313 Assert1(ElTy, "Invalid indices for GEP pointer type!", &GEP);
314 Assert2(PointerType::get(ElTy) == GEP.getType(),
315 "GEP is not of right type for indices!", &GEP, ElTy);
316 visitInstruction(GEP);
319 void Verifier::visitLoadInst(LoadInst &LI) {
320 const Type *ElTy = LoadInst::getIndexedType(LI.getOperand(0)->getType(),
322 Assert1(ElTy, "Invalid indices for load pointer type!", &LI);
323 Assert2(ElTy == LI.getType(),
324 "Load is not of right type for indices!", &LI, ElTy);
325 visitInstruction(LI);
328 void Verifier::visitStoreInst(StoreInst &SI) {
329 const Type *ElTy = StoreInst::getIndexedType(SI.getOperand(1)->getType(),
331 Assert1(ElTy, "Invalid indices for store pointer type!", &SI);
332 Assert2(ElTy == SI.getOperand(0)->getType(),
333 "Stored value is not of right type for indices!", &SI, ElTy);
334 visitInstruction(SI);
338 // verifyInstruction - Verify that a non-terminator instruction is well formed.
340 void Verifier::visitInstruction(Instruction &I) {
341 Assert1(I.getParent(), "Instruction not embedded in basic block!", &I);
343 // Check that all uses of the instruction, if they are instructions
344 // themselves, actually have parent basic blocks. If the use is not an
345 // instruction, it is an error!
347 for (User::use_iterator UI = I.use_begin(), UE = I.use_end();
349 Assert1(isa<Instruction>(*UI), "Use of instruction is not an instruction!",
351 Instruction *Used = cast<Instruction>(*UI);
352 Assert2(Used->getParent() != 0, "Instruction referencing instruction not"
353 " embeded in a basic block!", &I, Used);
356 if (!isa<PHINode>(I)) { // Check that non-phi nodes are not self referential
357 for (Value::use_iterator UI = I.use_begin(), UE = I.use_end();
359 Assert1(*UI != (User*)&I,
360 "Only PHI nodes may reference their own value!", &I);
363 Assert1(I.getType() != Type::VoidTy || !I.hasName(),
364 "Instruction has a name, but provides a void value!", &I);
368 //===----------------------------------------------------------------------===//
369 // Implement the public interfaces to this file...
370 //===----------------------------------------------------------------------===//
372 Pass *createVerifierPass() {
373 return new Verifier();
376 bool verifyFunction(const Function &F) {
378 V.visit((Function&)F);
382 // verifyModule - Check a module for errors, printing messages on stderr.
383 // Return true if the module is corrupt.
385 bool verifyModule(const Module &M) {