llvm-6502/lib/VMCore/Verifier.cpp

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//===-- Verifier.cpp - Implement the Module Verifier -------------*- C++ -*-==//
//
// This file defines the function verifier interface, that can be used for some
// sanity checking of input to the system.
//
// Note that this does not provide full 'java style' security and verifications,
// instead it just tries to ensure that code is well formed.
//
// . There are no duplicated names in a symbol table... ie there !exist a val
// with the same name as something in the symbol table, but with a different
// address as what is in the symbol table...
// * Both of a binary operator's parameters are the same type
// * Verify that the indices of mem access instructions match other operands
// . Verify that arithmetic and other things are only performed on first class
// types. No adding structures or arrays.
// . All of the constants in a switch statement are of the correct type
// . The code is in valid SSA form
// . It should be illegal to put a label into any other type (like a structure)
// or to return one. [except constant arrays!]
// * Only phi nodes can be self referential: 'add int %0, %0 ; <int>:0' is bad
// * PHI nodes must have an entry for each predecessor, with no extras.
// . All basic blocks should only end with terminator insts, not contain them
// * The entry node to a function must not have predecessors
// * All Instructions must be embeded into a basic block
// . Verify that none of the Value getType()'s are null.
// . Function's cannot take a void typed parameter
// * Verify that a function's argument list agrees with it's declared type.
// . Verify that arrays and structures have fixed elements: No unsized arrays.
// * It is illegal to specify a name for a void value.
// * It is illegal to have a internal function that is just a declaration
// * It is illegal to have a ret instruction that returns a value that does not
// agree with the function return value type.
// * All other things that are tested by asserts spread about the code...
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/Verifier.h"
#include "llvm/Pass.h"
#include "llvm/Function.h"
#include "llvm/Module.h"
#include "llvm/BasicBlock.h"
#include "llvm/DerivedTypes.h"
#include "llvm/iPHINode.h"
#include "llvm/iTerminators.h"
#include "llvm/iOther.h"
#include "llvm/iMemory.h"
#include "llvm/Argument.h"
#include "llvm/SymbolTable.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/InstVisitor.h"
#include "Support/STLExtras.h"
#include <algorithm>
namespace { // Anonymous namespace for class
struct Verifier : public MethodPass, InstVisitor<Verifier> {
bool Broken;
Verifier() : Broken(false) {}
bool doInitialization(Module *M) {
verifySymbolTable(M->getSymbolTable());
return false;
}
bool runOnMethod(Function *F) {
visit(F);
return false;
}
bool doFinalization(Module *M) {
if (Broken) {
cerr << "Broken module found, compilation aborted!\n";
abort();
}
return false;
}
// Verification methods...
void verifySymbolTable(SymbolTable *ST);
void visitFunction(Function *F);
void visitBasicBlock(BasicBlock *BB);
void visitPHINode(PHINode *PN);
void visitBinaryOperator(BinaryOperator *B);
void visitCallInst(CallInst *CI);
void visitGetElementPtrInst(GetElementPtrInst *GEP);
void visitLoadInst(LoadInst *LI);
void visitStoreInst(StoreInst *SI);
void visitInstruction(Instruction *I);
// CheckFailed - A check failed, so print out the condition and the message
// that failed. This provides a nice place to put a breakpoint if you want
// to see why something is not correct.
//
inline void CheckFailed(const char *Cond, const std::string &Message,
const Value *V1 = 0, const Value *V2 = 0) {
std::cerr << Message << "\n";
if (V1) { std::cerr << V1 << "\n"; }
if (V2) { std::cerr << V2 << "\n"; }
Broken = true;
}
};
}
// Assert - We know that cond should be true, if not print an error message.
#define Assert(C, M) \
do { if (!(C)) { CheckFailed(#C, M); return; } } while (0)
#define Assert1(C, M, V1) \
do { if (!(C)) { CheckFailed(#C, M, V1); return; } } while (0)
#define Assert2(C, M, V1, V2) \
do { if (!(C)) { CheckFailed(#C, M, V1, V2); return; } } while (0)
// verifySymbolTable - Verify that a function or module symbol table is ok
//
void Verifier::verifySymbolTable(SymbolTable *ST) {
if (ST == 0) return; // No symbol table to process
// Loop over all of the types in the symbol table...
for (SymbolTable::iterator TI = ST->begin(), TE = ST->end(); TI != TE; ++TI)
for (SymbolTable::type_iterator I = TI->second.begin(),
E = TI->second.end(); I != E; ++I) {
Value *V = I->second;
// Check that there are no void typed values in the symbol table. Values
// with a void type cannot be put into symbol tables because they cannot
// have names!
Assert1(V->getType() != Type::VoidTy,
"Values with void type are not allowed to have names!\n", V);
}
}
// visitFunction - Verify that a function is ok.
//
void Verifier::visitFunction(Function *F) {
if (F->isExternal()) return;
verifySymbolTable(F->getSymbolTable());
// Check linkage of function...
Assert1(!F->isExternal() || F->hasExternalLinkage(),
"Function cannot be an 'internal' 'declare'ation!", F);
// Check function arguments...
const FunctionType *FT = F->getFunctionType();
const Function::ArgumentListType &ArgList = F->getArgumentList();
Assert2(!FT->isVarArg(), "Cannot define varargs functions in LLVM!", F, FT);
Assert2(FT->getParamTypes().size() == ArgList.size(),
"# formal arguments must match # of arguments for function type!",
F, FT);
// Check that the argument values match the function type for this function...
if (FT->getParamTypes().size() == ArgList.size()) {
for (unsigned i = 0, e = ArgList.size(); i != e; ++i)
Assert2(ArgList[i]->getType() == FT->getParamType(i),
"Argument value does not match function argument type!",
ArgList[i], FT->getParamType(i));
}
// Check the entry node
BasicBlock *Entry = F->getEntryNode();
Assert1(pred_begin(Entry) == pred_end(Entry),
"Entry block to function must not have predecessors!", Entry);
}
// verifyBasicBlock - Verify that a basic block is well formed...
//
void Verifier::visitBasicBlock(BasicBlock *BB) {
Assert1(BB->getTerminator(), "Basic Block does not have terminator!\n", BB);
// Check that the terminator is ok as well...
if (isa<ReturnInst>(BB->getTerminator())) {
Instruction *I = BB->getTerminator();
Function *F = I->getParent()->getParent();
if (I->getNumOperands() == 0)
Assert1(F->getReturnType() == Type::VoidTy,
"Function returns no value, but ret instruction found that does!",
I);
else
Assert2(F->getReturnType() == I->getOperand(0)->getType(),
"Function return type does not match operand "
"type of return inst!", I, F->getReturnType());
}
}
// visitPHINode - Ensure that a PHI node is well formed.
void Verifier::visitPHINode(PHINode *PN) {
std::vector<BasicBlock*> Preds(pred_begin(PN->getParent()),
pred_end(PN->getParent()));
// Loop over all of the incoming values, make sure that there are
// predecessors for each one...
//
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
// Make sure all of the incoming values are the right types...
Assert2(PN->getType() == PN->getIncomingValue(i)->getType(),
"PHI node argument type does not agree with PHI node type!",
PN, PN->getIncomingValue(i));
BasicBlock *BB = PN->getIncomingBlock(i);
std::vector<BasicBlock*>::iterator PI =
find(Preds.begin(), Preds.end(), BB);
Assert2(PI != Preds.end(), "PHI node has entry for basic block that"
" is not a predecessor!", PN, BB);
Preds.erase(PI);
}
// There should be no entries left in the predecessor list...
for (std::vector<BasicBlock*>::iterator I = Preds.begin(),
E = Preds.end(); I != E; ++I)
Assert2(0, "PHI node does not have entry for a predecessor basic block!",
PN, *I);
visitInstruction(PN);
}
void Verifier::visitCallInst(CallInst *CI) {
Assert1(isa<PointerType>(CI->getOperand(0)->getType()),
"Called function must be a pointer!", CI);
PointerType *FPTy = cast<PointerType>(CI->getOperand(0)->getType());
Assert1(isa<FunctionType>(FPTy->getElementType()),
"Called function is not pointer to function type!", CI);
}
// visitBinaryOperator - Check that both arguments to the binary operator are
// of the same type!
//
void Verifier::visitBinaryOperator(BinaryOperator *B) {
Assert2(B->getOperand(0)->getType() == B->getOperand(1)->getType(),
"Both operands to a binary operator are not of the same type!",
B->getOperand(0), B->getOperand(1));
visitInstruction(B);
}
void Verifier::visitGetElementPtrInst(GetElementPtrInst *GEP) {
const Type *ElTy =MemAccessInst::getIndexedType(GEP->getOperand(0)->getType(),
GEP->copyIndices(), true);
Assert1(ElTy, "Invalid indices for GEP pointer type!", GEP);
Assert2(PointerType::get(ElTy) == GEP->getType(),
"GEP is not of right type for indices!\n", GEP, ElTy);
visitInstruction(GEP);
}
void Verifier::visitLoadInst(LoadInst *LI) {
const Type *ElTy = LoadInst::getIndexedType(LI->getOperand(0)->getType(),
LI->copyIndices());
Assert1(ElTy, "Invalid indices for load pointer type!", LI);
Assert2(ElTy == LI->getType(),
"Load is not of right type for indices!\n", LI, ElTy);
visitInstruction(LI);
}
void Verifier::visitStoreInst(StoreInst *SI) {
const Type *ElTy = StoreInst::getIndexedType(SI->getOperand(1)->getType(),
SI->copyIndices());
Assert1(ElTy, "Invalid indices for store pointer type!", SI);
Assert2(ElTy == SI->getOperand(0)->getType(),
"Stored value is not of right type for indices!\n", SI, ElTy);
visitInstruction(SI);
}
// verifyInstruction - Verify that a non-terminator instruction is well formed.
//
void Verifier::visitInstruction(Instruction *I) {
assert(I->getParent() && "Instruction not embedded in basic block!");
// Check that all uses of the instruction, if they are instructions
// themselves, actually have parent basic blocks. If the use is not an
// instruction, it is an error!
//
for (User::use_iterator UI = I->use_begin(), UE = I->use_end();
UI != UE; ++UI) {
Assert1(isa<Instruction>(*UI), "Use of instruction is not an instruction!",
*UI);
Instruction *Used = cast<Instruction>(*UI);
Assert2(Used->getParent() != 0, "Instruction referencing instruction not"
" embeded in a basic block!", I, Used);
}
if (!isa<PHINode>(I)) { // Check that non-phi nodes are not self referential
for (Value::use_iterator UI = I->use_begin(), UE = I->use_end();
UI != UE; ++UI)
Assert1(*UI != (User*)I,
"Only PHI nodes may reference their own value!", I);
}
Assert1(I->getType() != Type::VoidTy || !I->hasName(),
"Instruction has a name, but provides a void value!", I);
}
//===----------------------------------------------------------------------===//
// Implement the public interfaces to this file...
//===----------------------------------------------------------------------===//
Pass *createVerifierPass() {
return new Verifier();
}
bool verifyFunction(const Function *F) {
Verifier V;
V.visit((Function*)F);
return V.Broken;
}
// verifyModule - Check a module for errors, printing messages on stderr.
// Return true if the module is corrupt.
//
bool verifyModule(const Module *M) {
Verifier V;
V.run((Module*)M);
return V.Broken;
}