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 // . All basic blocks should only end with terminator insts, not contain them
23 // * The entry node to a function must not have predecessors
24 // * All Instructions must be embeded into a basic block
25 // . Verify that none of the Value getType()'s are null.
26 // . Function's cannot take a void typed parameter
27 // * Verify that a function's argument list agrees with it's declared type.
28 // . Verify that arrays and structures have fixed elements: No unsized arrays.
29 // * It is illegal to specify a name for a void value.
30 // * It is illegal to have a internal function that is just a declaration
31 // * It is illegal to have a ret instruction that returns a value that does not
32 // agree with the function return value type.
33 // * Function call argument types match the function prototype
34 // * All other things that are tested by asserts spread about the code...
36 //===----------------------------------------------------------------------===//
38 #include "llvm/Analysis/Verifier.h"
39 #include "llvm/Pass.h"
40 #include "llvm/Module.h"
41 #include "llvm/DerivedTypes.h"
42 #include "llvm/iPHINode.h"
43 #include "llvm/iTerminators.h"
44 #include "llvm/iOther.h"
45 #include "llvm/iMemory.h"
46 #include "llvm/Argument.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);
101 // CheckFailed - A check failed, so print out the condition and the message
102 // that failed. This provides a nice place to put a breakpoint if you want
103 // to see why something is not correct.
105 inline void CheckFailed(const std::string &Message,
106 const Value *V1 = 0, const Value *V2 = 0) {
107 std::cerr << Message << "\n";
108 if (V1) { std::cerr << V1 << "\n"; }
109 if (V2) { std::cerr << V2 << "\n"; }
115 // Assert - We know that cond should be true, if not print an error message.
116 #define Assert(C, M) \
117 do { if (!(C)) { CheckFailed(M); return; } } while (0)
118 #define Assert1(C, M, V1) \
119 do { if (!(C)) { CheckFailed(M, V1); return; } } while (0)
120 #define Assert2(C, M, V1, V2) \
121 do { if (!(C)) { CheckFailed(M, V1, V2); return; } } while (0)
124 // verifySymbolTable - Verify that a function or module symbol table is ok
126 void Verifier::verifySymbolTable(SymbolTable *ST) {
127 if (ST == 0) return; // No symbol table to process
129 // Loop over all of the types in the symbol table...
130 for (SymbolTable::iterator TI = ST->begin(), TE = ST->end(); TI != TE; ++TI)
131 for (SymbolTable::type_iterator I = TI->second.begin(),
132 E = TI->second.end(); I != E; ++I) {
133 Value *V = I->second;
135 // Check that there are no void typed values in the symbol table. Values
136 // with a void type cannot be put into symbol tables because they cannot
138 Assert1(V->getType() != Type::VoidTy,
139 "Values with void type are not allowed to have names!", V);
144 // visitFunction - Verify that a function is ok.
146 void Verifier::visitFunction(Function *F) {
147 if (F->isExternal()) return;
149 verifySymbolTable(F->getSymbolTable());
151 // Check function arguments...
152 const FunctionType *FT = F->getFunctionType();
153 const Function::ArgumentListType &ArgList = F->getArgumentList();
155 Assert2(!FT->isVarArg(), "Cannot define varargs functions in LLVM!", F, FT);
156 Assert2(FT->getParamTypes().size() == ArgList.size(),
157 "# formal arguments must match # of arguments for function type!",
160 // Check that the argument values match the function type for this function...
161 if (FT->getParamTypes().size() == ArgList.size()) {
162 for (unsigned i = 0, e = ArgList.size(); i != e; ++i)
163 Assert2(ArgList[i]->getType() == FT->getParamType(i),
164 "Argument value does not match function argument type!",
165 ArgList[i], FT->getParamType(i));
168 // Check the entry node
169 BasicBlock *Entry = F->getEntryNode();
170 Assert1(pred_begin(Entry) == pred_end(Entry),
171 "Entry block to function must not have predecessors!", Entry);
175 // verifyBasicBlock - Verify that a basic block is well formed...
177 void Verifier::visitBasicBlock(BasicBlock *BB) {
178 Assert1(BB->getTerminator(), "Basic Block does not have terminator!", BB);
180 // Check that the terminator is ok as well...
181 if (isa<ReturnInst>(BB->getTerminator())) {
182 Instruction *I = BB->getTerminator();
183 Function *F = I->getParent()->getParent();
184 if (I->getNumOperands() == 0)
185 Assert1(F->getReturnType() == Type::VoidTy,
186 "Function returns no value, but ret instruction found that does!",
189 Assert2(F->getReturnType() == I->getOperand(0)->getType(),
190 "Function return type does not match operand "
191 "type of return inst!", I, F->getReturnType());
196 // visitPHINode - Ensure that a PHI node is well formed.
197 void Verifier::visitPHINode(PHINode *PN) {
198 std::vector<BasicBlock*> Preds(pred_begin(PN->getParent()),
199 pred_end(PN->getParent()));
200 // Loop over all of the incoming values, make sure that there are
201 // predecessors for each one...
203 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
204 // Make sure all of the incoming values are the right types...
205 Assert2(PN->getType() == PN->getIncomingValue(i)->getType(),
206 "PHI node argument type does not agree with PHI node type!",
207 PN, PN->getIncomingValue(i));
209 BasicBlock *BB = PN->getIncomingBlock(i);
210 std::vector<BasicBlock*>::iterator PI =
211 find(Preds.begin(), Preds.end(), BB);
212 Assert2(PI != Preds.end(), "PHI node has entry for basic block that"
213 " is not a predecessor!", PN, BB);
217 // There should be no entries left in the predecessor list...
218 for (std::vector<BasicBlock*>::iterator I = Preds.begin(),
219 E = Preds.end(); I != E; ++I)
220 Assert2(0, "PHI node does not have entry for a predecessor basic block!",
223 visitInstruction(PN);
226 void Verifier::visitCallInst(CallInst *CI) {
227 Assert1(isa<PointerType>(CI->getOperand(0)->getType()),
228 "Called function must be a pointer!", CI);
229 PointerType *FPTy = cast<PointerType>(CI->getOperand(0)->getType());
230 Assert1(isa<FunctionType>(FPTy->getElementType()),
231 "Called function is not pointer to function type!", CI);
233 FunctionType *FTy = cast<FunctionType>(FPTy->getElementType());
235 // Verify that the correct number of arguments are being passed
237 Assert1(CI->getNumOperands()-1 >= FTy->getNumParams(),
238 "Called function requires more parameters than were provided!", CI);
240 Assert1(CI->getNumOperands()-1 == FTy->getNumParams(),
241 "Incorrect number of arguments passed to called function!", CI);
243 // Verify that all arguments to the call match the function type...
244 for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
245 Assert2(CI->getOperand(i+1)->getType() == FTy->getParamType(i),
246 "Call parameter type does not match function signature!",
247 CI->getOperand(i+1), FTy->getParamType(i));
250 // visitBinaryOperator - Check that both arguments to the binary operator are
253 void Verifier::visitBinaryOperator(BinaryOperator *B) {
254 Assert2(B->getOperand(0)->getType() == B->getOperand(1)->getType(),
255 "Both operands to a binary operator are not of the same type!",
256 B->getOperand(0), B->getOperand(1));
261 void Verifier::visitGetElementPtrInst(GetElementPtrInst *GEP) {
262 const Type *ElTy =MemAccessInst::getIndexedType(GEP->getOperand(0)->getType(),
263 GEP->copyIndices(), true);
264 Assert1(ElTy, "Invalid indices for GEP pointer type!", GEP);
265 Assert2(PointerType::get(ElTy) == GEP->getType(),
266 "GEP is not of right type for indices!", GEP, ElTy);
267 visitInstruction(GEP);
270 void Verifier::visitLoadInst(LoadInst *LI) {
271 const Type *ElTy = LoadInst::getIndexedType(LI->getOperand(0)->getType(),
273 Assert1(ElTy, "Invalid indices for load pointer type!", LI);
274 Assert2(ElTy == LI->getType(),
275 "Load is not of right type for indices!", LI, ElTy);
276 visitInstruction(LI);
279 void Verifier::visitStoreInst(StoreInst *SI) {
280 const Type *ElTy = StoreInst::getIndexedType(SI->getOperand(1)->getType(),
282 Assert1(ElTy, "Invalid indices for store pointer type!", SI);
283 Assert2(ElTy == SI->getOperand(0)->getType(),
284 "Stored value is not of right type for indices!", SI, ElTy);
285 visitInstruction(SI);
289 // verifyInstruction - Verify that a non-terminator instruction is well formed.
291 void Verifier::visitInstruction(Instruction *I) {
292 assert(I->getParent() && "Instruction not embedded in basic block!");
294 // Check that all uses of the instruction, if they are instructions
295 // themselves, actually have parent basic blocks. If the use is not an
296 // instruction, it is an error!
298 for (User::use_iterator UI = I->use_begin(), UE = I->use_end();
300 Assert1(isa<Instruction>(*UI), "Use of instruction is not an instruction!",
302 Instruction *Used = cast<Instruction>(*UI);
303 Assert2(Used->getParent() != 0, "Instruction referencing instruction not"
304 " embeded in a basic block!", I, Used);
307 if (!isa<PHINode>(I)) { // Check that non-phi nodes are not self referential
308 for (Value::use_iterator UI = I->use_begin(), UE = I->use_end();
310 Assert1(*UI != (User*)I,
311 "Only PHI nodes may reference their own value!", I);
314 Assert1(I->getType() != Type::VoidTy || !I->hasName(),
315 "Instruction has a name, but provides a void value!", I);
319 //===----------------------------------------------------------------------===//
320 // Implement the public interfaces to this file...
321 //===----------------------------------------------------------------------===//
323 Pass *createVerifierPass() {
324 return new Verifier();
327 bool verifyFunction(const Function *F) {
329 V.visit((Function*)F);
333 // verifyModule - Check a module for errors, printing messages on stderr.
334 // Return true if the module is corrupt.
336 bool verifyModule(const Module *M) {