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 // * All other things that are tested by asserts spread about the code...
35 //===----------------------------------------------------------------------===//
37 #include "llvm/Analysis/Verifier.h"
38 #include "llvm/Pass.h"
39 #include "llvm/Function.h"
40 #include "llvm/Module.h"
41 #include "llvm/BasicBlock.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/Argument.h"
48 #include "llvm/SymbolTable.h"
49 #include "llvm/Support/CFG.h"
50 #include "llvm/Support/InstVisitor.h"
51 #include "Support/STLExtras.h"
54 namespace { // Anonymous namespace for class
56 struct Verifier : public FunctionPass, InstVisitor<Verifier> {
59 Verifier() : Broken(false) {}
61 bool doInitialization(Module *M) {
62 verifySymbolTable(M->getSymbolTable());
66 bool runOnFunction(Function *F) {
71 bool doFinalization(Module *M) {
73 cerr << "Broken module found, compilation aborted!\n";
79 // Verification methods...
80 void verifySymbolTable(SymbolTable *ST);
81 void visitFunction(Function *F);
82 void visitBasicBlock(BasicBlock *BB);
83 void visitPHINode(PHINode *PN);
84 void visitBinaryOperator(BinaryOperator *B);
85 void visitCallInst(CallInst *CI);
86 void visitGetElementPtrInst(GetElementPtrInst *GEP);
87 void visitLoadInst(LoadInst *LI);
88 void visitStoreInst(StoreInst *SI);
89 void visitInstruction(Instruction *I);
91 // CheckFailed - A check failed, so print out the condition and the message
92 // that failed. This provides a nice place to put a breakpoint if you want
93 // to see why something is not correct.
95 inline void CheckFailed(const char *Cond, const std::string &Message,
96 const Value *V1 = 0, const Value *V2 = 0) {
97 std::cerr << Message << "\n";
98 if (V1) { std::cerr << V1 << "\n"; }
99 if (V2) { std::cerr << V2 << "\n"; }
105 // Assert - We know that cond should be true, if not print an error message.
106 #define Assert(C, M) \
107 do { if (!(C)) { CheckFailed(#C, M); return; } } while (0)
108 #define Assert1(C, M, V1) \
109 do { if (!(C)) { CheckFailed(#C, M, V1); return; } } while (0)
110 #define Assert2(C, M, V1, V2) \
111 do { if (!(C)) { CheckFailed(#C, M, V1, V2); return; } } while (0)
114 // verifySymbolTable - Verify that a function or module symbol table is ok
116 void Verifier::verifySymbolTable(SymbolTable *ST) {
117 if (ST == 0) return; // No symbol table to process
119 // Loop over all of the types in the symbol table...
120 for (SymbolTable::iterator TI = ST->begin(), TE = ST->end(); TI != TE; ++TI)
121 for (SymbolTable::type_iterator I = TI->second.begin(),
122 E = TI->second.end(); I != E; ++I) {
123 Value *V = I->second;
125 // Check that there are no void typed values in the symbol table. Values
126 // with a void type cannot be put into symbol tables because they cannot
128 Assert1(V->getType() != Type::VoidTy,
129 "Values with void type are not allowed to have names!\n", V);
134 // visitFunction - Verify that a function is ok.
136 void Verifier::visitFunction(Function *F) {
137 if (F->isExternal()) return;
138 verifySymbolTable(F->getSymbolTable());
140 // Check linkage of function...
141 Assert1(!F->isExternal() || F->hasExternalLinkage(),
142 "Function cannot be an 'internal' 'declare'ation!", F);
144 // Check function arguments...
145 const FunctionType *FT = F->getFunctionType();
146 const Function::ArgumentListType &ArgList = F->getArgumentList();
148 Assert2(!FT->isVarArg(), "Cannot define varargs functions in LLVM!", F, FT);
149 Assert2(FT->getParamTypes().size() == ArgList.size(),
150 "# formal arguments must match # of arguments for function type!",
153 // Check that the argument values match the function type for this function...
154 if (FT->getParamTypes().size() == ArgList.size()) {
155 for (unsigned i = 0, e = ArgList.size(); i != e; ++i)
156 Assert2(ArgList[i]->getType() == FT->getParamType(i),
157 "Argument value does not match function argument type!",
158 ArgList[i], FT->getParamType(i));
161 // Check the entry node
162 BasicBlock *Entry = F->getEntryNode();
163 Assert1(pred_begin(Entry) == pred_end(Entry),
164 "Entry block to function must not have predecessors!", Entry);
168 // verifyBasicBlock - Verify that a basic block is well formed...
170 void Verifier::visitBasicBlock(BasicBlock *BB) {
171 Assert1(BB->getTerminator(), "Basic Block does not have terminator!\n", BB);
173 // Check that the terminator is ok as well...
174 if (isa<ReturnInst>(BB->getTerminator())) {
175 Instruction *I = BB->getTerminator();
176 Function *F = I->getParent()->getParent();
177 if (I->getNumOperands() == 0)
178 Assert1(F->getReturnType() == Type::VoidTy,
179 "Function returns no value, but ret instruction found that does!",
182 Assert2(F->getReturnType() == I->getOperand(0)->getType(),
183 "Function return type does not match operand "
184 "type of return inst!", I, F->getReturnType());
189 // visitPHINode - Ensure that a PHI node is well formed.
190 void Verifier::visitPHINode(PHINode *PN) {
191 std::vector<BasicBlock*> Preds(pred_begin(PN->getParent()),
192 pred_end(PN->getParent()));
193 // Loop over all of the incoming values, make sure that there are
194 // predecessors for each one...
196 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
197 // Make sure all of the incoming values are the right types...
198 Assert2(PN->getType() == PN->getIncomingValue(i)->getType(),
199 "PHI node argument type does not agree with PHI node type!",
200 PN, PN->getIncomingValue(i));
202 BasicBlock *BB = PN->getIncomingBlock(i);
203 std::vector<BasicBlock*>::iterator PI =
204 find(Preds.begin(), Preds.end(), BB);
205 Assert2(PI != Preds.end(), "PHI node has entry for basic block that"
206 " is not a predecessor!", PN, BB);
210 // There should be no entries left in the predecessor list...
211 for (std::vector<BasicBlock*>::iterator I = Preds.begin(),
212 E = Preds.end(); I != E; ++I)
213 Assert2(0, "PHI node does not have entry for a predecessor basic block!",
216 visitInstruction(PN);
219 void Verifier::visitCallInst(CallInst *CI) {
220 Assert1(isa<PointerType>(CI->getOperand(0)->getType()),
221 "Called function must be a pointer!", CI);
222 PointerType *FPTy = cast<PointerType>(CI->getOperand(0)->getType());
223 Assert1(isa<FunctionType>(FPTy->getElementType()),
224 "Called function is not pointer to function type!", CI);
227 // visitBinaryOperator - Check that both arguments to the binary operator are
230 void Verifier::visitBinaryOperator(BinaryOperator *B) {
231 Assert2(B->getOperand(0)->getType() == B->getOperand(1)->getType(),
232 "Both operands to a binary operator are not of the same type!",
233 B->getOperand(0), B->getOperand(1));
238 void Verifier::visitGetElementPtrInst(GetElementPtrInst *GEP) {
239 const Type *ElTy =MemAccessInst::getIndexedType(GEP->getOperand(0)->getType(),
240 GEP->copyIndices(), true);
241 Assert1(ElTy, "Invalid indices for GEP pointer type!", GEP);
242 Assert2(PointerType::get(ElTy) == GEP->getType(),
243 "GEP is not of right type for indices!\n", GEP, ElTy);
244 visitInstruction(GEP);
247 void Verifier::visitLoadInst(LoadInst *LI) {
248 const Type *ElTy = LoadInst::getIndexedType(LI->getOperand(0)->getType(),
250 Assert1(ElTy, "Invalid indices for load pointer type!", LI);
251 Assert2(ElTy == LI->getType(),
252 "Load is not of right type for indices!\n", LI, ElTy);
253 visitInstruction(LI);
256 void Verifier::visitStoreInst(StoreInst *SI) {
257 const Type *ElTy = StoreInst::getIndexedType(SI->getOperand(1)->getType(),
259 Assert1(ElTy, "Invalid indices for store pointer type!", SI);
260 Assert2(ElTy == SI->getOperand(0)->getType(),
261 "Stored value is not of right type for indices!\n", SI, ElTy);
262 visitInstruction(SI);
266 // verifyInstruction - Verify that a non-terminator instruction is well formed.
268 void Verifier::visitInstruction(Instruction *I) {
269 assert(I->getParent() && "Instruction not embedded in basic block!");
271 // Check that all uses of the instruction, if they are instructions
272 // themselves, actually have parent basic blocks. If the use is not an
273 // instruction, it is an error!
275 for (User::use_iterator UI = I->use_begin(), UE = I->use_end();
277 Assert1(isa<Instruction>(*UI), "Use of instruction is not an instruction!",
279 Instruction *Used = cast<Instruction>(*UI);
280 Assert2(Used->getParent() != 0, "Instruction referencing instruction not"
281 " embeded in a basic block!", I, Used);
284 if (!isa<PHINode>(I)) { // Check that non-phi nodes are not self referential
285 for (Value::use_iterator UI = I->use_begin(), UE = I->use_end();
287 Assert1(*UI != (User*)I,
288 "Only PHI nodes may reference their own value!", I);
291 Assert1(I->getType() != Type::VoidTy || !I->hasName(),
292 "Instruction has a name, but provides a void value!", I);
296 //===----------------------------------------------------------------------===//
297 // Implement the public interfaces to this file...
298 //===----------------------------------------------------------------------===//
300 Pass *createVerifierPass() {
301 return new Verifier();
304 bool verifyFunction(const Function *F) {
306 V.visit((Function*)F);
310 // verifyModule - Check a module for errors, printing messages on stderr.
311 // Return true if the module is corrupt.
313 bool verifyModule(const Module *M) {