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 arithmetic and other things are only performed on first class
14 // types. No adding structures or arrays.
15 // . All of the constants in a switch statement are of the correct type
16 // . The code is in valid SSA form
17 // . It should be illegal to put a label into any other type (like a structure)
18 // or to return one. [except constant arrays!]
19 // * Only phi nodes can be self referential: 'add int %0, %0 ; <int>:0' is bad
20 // * PHI nodes must have an entry for each predecessor, with no extras.
21 // . All basic blocks should only end with terminator insts, not contain them
22 // * The entry node to a function must not have predecessors
23 // * All Instructions must be embeded into a basic block
24 // . Verify that none of the Value getType()'s are null.
25 // . Function's cannot take a void typed parameter
26 // * Verify that a function's argument list agrees with it's declared type.
27 // . Verify that arrays and structures have fixed elements: No unsized arrays.
28 // * It is illegal to specify a name for a void value.
29 // * It is illegal to have a internal function that is just a declaration
30 // * It is illegal to have a ret instruction that returns a value that does not
31 // agree with the function return value type.
32 // . All other things that are tested by asserts spread about the code...
34 //===----------------------------------------------------------------------===//
36 #include "llvm/Analysis/Verifier.h"
37 #include "llvm/Pass.h"
38 #include "llvm/Function.h"
39 #include "llvm/Module.h"
40 #include "llvm/BasicBlock.h"
41 #include "llvm/DerivedTypes.h"
42 #include "llvm/iPHINode.h"
43 #include "llvm/iTerminators.h"
44 #include "llvm/iOther.h"
45 #include "llvm/Argument.h"
46 #include "llvm/SymbolTable.h"
47 #include "llvm/Support/CFG.h"
48 #include "llvm/Support/InstVisitor.h"
49 #include "Support/STLExtras.h"
52 namespace { // Anonymous namespace for class
54 struct Verifier : public MethodPass, InstVisitor<Verifier> {
57 Verifier() : Broken(false) {}
59 bool doInitialization(Module *M) {
60 verifySymbolTable(M->getSymbolTable());
64 bool runOnMethod(Function *F) {
69 // Verification methods...
70 void verifySymbolTable(SymbolTable *ST);
71 void visitFunction(Function *F);
72 void visitBasicBlock(BasicBlock *BB);
73 void visitPHINode(PHINode *PN);
74 void visitBinaryOperator(BinaryOperator *B);
75 void visitCallInst(CallInst *CI);
76 void visitInstruction(Instruction *I);
78 // CheckFailed - A check failed, so print out the condition and the message
79 // that failed. This provides a nice place to put a breakpoint if you want
80 // to see why something is not correct.
82 inline void CheckFailed(const char *Cond, const std::string &Message,
83 const Value *V1 = 0, const Value *V2 = 0) {
84 std::cerr << Message << "\n";
85 if (V1) { std::cerr << V1 << "\n"; }
86 if (V2) { std::cerr << V2 << "\n"; }
92 // Assert - We know that cond should be true, if not print an error message.
93 #define Assert(C, M) \
94 do { if (!(C)) { CheckFailed(#C, M); return; } } while (0)
95 #define Assert1(C, M, V1) \
96 do { if (!(C)) { CheckFailed(#C, M, V1); return; } } while (0)
97 #define Assert2(C, M, V1, V2) \
98 do { if (!(C)) { CheckFailed(#C, M, V1, V2); return; } } while (0)
101 // verifySymbolTable - Verify that a function or module symbol table is ok
103 void Verifier::verifySymbolTable(SymbolTable *ST) {
104 if (ST == 0) return; // No symbol table to process
106 // Loop over all of the types in the symbol table...
107 for (SymbolTable::iterator TI = ST->begin(), TE = ST->end(); TI != TE; ++TI)
108 for (SymbolTable::type_iterator I = TI->second.begin(),
109 E = TI->second.end(); I != E; ++I) {
110 Value *V = I->second;
112 // Check that there are no void typed values in the symbol table. Values
113 // with a void type cannot be put into symbol tables because they cannot
115 Assert1(V->getType() != Type::VoidTy,
116 "Values with void type are not allowed to have names!\n", V);
121 // visitFunction - Verify that a function is ok.
123 void Verifier::visitFunction(Function *F) {
124 if (F->isExternal()) return;
125 verifySymbolTable(F->getSymbolTable());
127 // Check linkage of function...
128 Assert1(!F->isExternal() || F->hasExternalLinkage(),
129 "Function cannot be an 'internal' 'declare'ation!", F);
131 // Check function arguments...
132 const FunctionType *FT = F->getFunctionType();
133 const Function::ArgumentListType &ArgList = F->getArgumentList();
135 Assert2(!FT->isVarArg(), "Cannot define varargs functions in LLVM!", F, FT);
136 Assert2(FT->getParamTypes().size() == ArgList.size(),
137 "# formal arguments must match # of arguments for function type!",
140 // Check that the argument values match the function type for this function...
141 if (FT->getParamTypes().size() == ArgList.size()) {
142 for (unsigned i = 0, e = ArgList.size(); i != e; ++i)
143 Assert2(ArgList[i]->getType() == FT->getParamType(i),
144 "Argument value does not match function argument type!",
145 ArgList[i], FT->getParamType(i));
148 // Check the entry node
149 BasicBlock *Entry = F->getEntryNode();
150 Assert1(pred_begin(Entry) == pred_end(Entry),
151 "Entry block to function must not have predecessors!", Entry);
155 // verifyBasicBlock - Verify that a basic block is well formed...
157 void Verifier::visitBasicBlock(BasicBlock *BB) {
158 Assert1(BB->getTerminator(), "Basic Block does not have terminator!\n", BB);
160 // Check that the terminator is ok as well...
161 if (isa<ReturnInst>(BB->getTerminator())) {
162 Instruction *I = BB->getTerminator();
163 Function *F = I->getParent()->getParent();
164 if (I->getNumOperands() == 0)
165 Assert1(F->getReturnType() == Type::VoidTy,
166 "Function returns no value, but ret instruction found that does!",
169 Assert2(F->getReturnType() == I->getOperand(0)->getType(),
170 "Function return type does not match operand "
171 "type of return inst!", I, F->getReturnType());
176 // visitPHINode - Ensure that a PHI node is well formed.
177 void Verifier::visitPHINode(PHINode *PN) {
178 std::vector<BasicBlock*> Preds(pred_begin(PN->getParent()),
179 pred_end(PN->getParent()));
180 // Loop over all of the incoming values, make sure that there are
181 // predecessors for each one...
183 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
184 // Make sure all of the incoming values are the right types...
185 Assert2(PN->getType() == PN->getIncomingValue(i)->getType(),
186 "PHI node argument type does not agree with PHI node type!",
187 PN, PN->getIncomingValue(i));
189 BasicBlock *BB = PN->getIncomingBlock(i);
190 std::vector<BasicBlock*>::iterator PI =
191 find(Preds.begin(), Preds.end(), BB);
192 Assert2(PI != Preds.end(), "PHI node has entry for basic block that"
193 " is not a predecessor!", PN, BB);
197 // There should be no entries left in the predecessor list...
198 for (std::vector<BasicBlock*>::iterator I = Preds.begin(),
199 E = Preds.end(); I != E; ++I)
200 Assert2(0, "PHI node does not have entry for a predecessor basic block!",
203 visitInstruction(PN);
206 void Verifier::visitCallInst(CallInst *CI) {
207 Assert1(isa<PointerType>(CI->getOperand(0)->getType()),
208 "Called function must be a pointer!", CI);
209 PointerType *FPTy = cast<PointerType>(CI->getOperand(0)->getType());
210 Assert1(isa<FunctionType>(FPTy->getElementType()),
211 "Called function is not pointer to function type!", CI);
214 // visitBinaryOperator - Check that both arguments to the binary operator are
217 void Verifier::visitBinaryOperator(BinaryOperator *B) {
218 Assert2(B->getOperand(0)->getType() == B->getOperand(1)->getType(),
219 "Both operands to a binary operator are not of the same type!",
220 B->getOperand(0), B->getOperand(1));
226 // verifyInstruction - Verify that a non-terminator instruction is well formed.
228 void Verifier::visitInstruction(Instruction *I) {
229 assert(I->getParent() && "Instruction not embedded in basic block!");
231 // Check that all uses of the instruction, if they are instructions
232 // themselves, actually have parent basic blocks. If the use is not an
233 // instruction, it is an error!
235 for (User::use_iterator UI = I->use_begin(), UE = I->use_end();
237 Assert1(isa<Instruction>(*UI), "Use of instruction is not an instruction!",
239 Instruction *Used = cast<Instruction>(*UI);
240 Assert2(Used->getParent() != 0, "Instruction referencing instruction not"
241 " embeded in a basic block!", I, Used);
244 if (!isa<PHINode>(I)) { // Check that non-phi nodes are not self referential
245 for (Value::use_iterator UI = I->use_begin(), UE = I->use_end();
247 Assert1(*UI != (User*)I,
248 "Only PHI nodes may reference their own value!", I);
251 Assert1(I->getType() != Type::VoidTy || !I->hasName(),
252 "Instruction has a name, but provides a void value!", I);
256 //===----------------------------------------------------------------------===//
257 // Implement the public interfaces to this file...
258 //===----------------------------------------------------------------------===//
260 Pass *createVerifierPass() {
261 return new Verifier();
264 bool verifyFunction(const Function *F) {
266 V.visit((Function*)F);
270 // verifyModule - Check a module for errors, printing messages on stderr.
271 // Return true if the module is corrupt.
273 bool verifyModule(const Module *M) {