llvm-6502/lib/VMCore/Verifier.cpp
Chris Lattner 6e6026b465 - Eliminated the deferred symbol table stuff in Module & Function, it really
wasn't an optimization and it was causing lots of bugs.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@4779 91177308-0d34-0410-b5e6-96231b3b80d8
2002-11-20 18:36:02 +00:00

510 lines
20 KiB
C++

//===-- 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.
//
// * 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. Verify that shifts & logicals only happen on integrals f.e.
// . 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.
// * PHI nodes must be the first thing in a basic block, all grouped together
// * PHI nodes must have at least one entry
// * 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
// . 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 global value with no intitalizer
// * It is illegal to have a ret instruction that returns a value that does not
// agree with the function return value type.
// * Function call argument types match the function prototype
// * All other things that are tested by asserts spread about the code...
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/Verifier.h"
#include "llvm/Pass.h"
#include "llvm/Module.h"
#include "llvm/DerivedTypes.h"
#include "llvm/iPHINode.h"
#include "llvm/iTerminators.h"
#include "llvm/iOther.h"
#include "llvm/iOperators.h"
#include "llvm/iMemory.h"
#include "llvm/SymbolTable.h"
#include "llvm/PassManager.h"
#include "llvm/Analysis/Dominators.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 FunctionPass, InstVisitor<Verifier> {
bool Broken; // Is this module found to be broken?
bool RealPass; // Are we not being run by a PassManager?
bool AbortBroken; // If broken, should it or should it not abort?
DominatorSet *DS; // Dominator set, caution can be null!
Verifier() : Broken(false), RealPass(true), AbortBroken(true), DS(0) {}
Verifier(bool AB) : Broken(false), RealPass(true), AbortBroken(AB), DS(0) {}
Verifier(DominatorSet &ds)
: Broken(false), RealPass(false), AbortBroken(false), DS(&ds) {}
bool doInitialization(Module &M) {
verifySymbolTable(M.getSymbolTable());
// If this is a real pass, in a pass manager, we must abort before
// returning back to the pass manager, or else the pass manager may try to
// run other passes on the broken module.
//
if (RealPass)
abortIfBroken();
return false;
}
bool runOnFunction(Function &F) {
// Get dominator information if we are being run by PassManager
if (RealPass) DS = &getAnalysis<DominatorSet>();
visit(F);
// If this is a real pass, in a pass manager, we must abort before
// returning back to the pass manager, or else the pass manager may try to
// run other passes on the broken module.
//
if (RealPass)
abortIfBroken();
return false;
}
bool doFinalization(Module &M) {
// Scan through, checking all of the external function's linkage now...
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
if (I->isExternal() && I->hasInternalLinkage())
CheckFailed("Function Declaration has Internal Linkage!", I);
for (Module::giterator I = M.gbegin(), E = M.gend(); I != E; ++I)
if (I->isExternal() && I->hasInternalLinkage())
CheckFailed("Global Variable is external with internal linkage!", I);
// If the module is broken, abort at this time.
abortIfBroken();
return false;
}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
if (RealPass)
AU.addRequired<DominatorSet>();
}
// abortIfBroken - If the module is broken and we are supposed to abort on
// this condition, do so.
//
void abortIfBroken() const {
if (Broken && AbortBroken) {
std::cerr << "Broken module found, compilation aborted!\n";
abort();
}
}
// Verification methods...
void verifySymbolTable(SymbolTable &ST);
void visitFunction(Function &F);
void visitBasicBlock(BasicBlock &BB);
void visitPHINode(PHINode &PN);
void visitBinaryOperator(BinaryOperator &B);
void visitShiftInst(ShiftInst &SI);
void visitCallInst(CallInst &CI);
void visitGetElementPtrInst(GetElementPtrInst &GEP);
void visitLoadInst(LoadInst &LI);
void visitStoreInst(StoreInst &SI);
void visitInstruction(Instruction &I);
void visitTerminatorInst(TerminatorInst &I);
void visitReturnInst(ReturnInst &RI);
// 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 std::string &Message,
const Value *V1 = 0, const Value *V2 = 0,
const Value *V3 = 0, const Value *V4 = 0) {
std::cerr << Message << "\n";
if (V1) std::cerr << *V1 << "\n";
if (V2) std::cerr << *V2 << "\n";
if (V3) std::cerr << *V3 << "\n";
if (V4) std::cerr << *V4 << "\n";
Broken = true;
}
};
RegisterPass<Verifier> X("verify", "Module Verifier");
}
// Assert - We know that cond should be true, if not print an error message.
#define Assert(C, M) \
do { if (!(C)) { CheckFailed(M); return; } } while (0)
#define Assert1(C, M, V1) \
do { if (!(C)) { CheckFailed(M, V1); return; } } while (0)
#define Assert2(C, M, V1, V2) \
do { if (!(C)) { CheckFailed(M, V1, V2); return; } } while (0)
#define Assert3(C, M, V1, V2, V3) \
do { if (!(C)) { CheckFailed(M, V1, V2, V3); return; } } while (0)
#define Assert4(C, M, V1, V2, V3, V4) \
do { if (!(C)) { CheckFailed(M, V1, V2, V3, V4); return; } } while (0)
// verifySymbolTable - Verify that a function or module symbol table is ok
//
void Verifier::verifySymbolTable(SymbolTable &ST) {
// 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!", V);
}
}
// visitFunction - Verify that a function is ok.
//
void Verifier::visitFunction(Function &F) {
// Check function arguments...
const FunctionType *FT = F.getFunctionType();
unsigned NumArgs = F.getArgumentList().size();
Assert2(!FT->isVarArg(), "Cannot define varargs functions in LLVM!", &F, FT);
Assert2(FT->getNumParams() == NumArgs,
"# formal arguments must match # of arguments for function type!",
&F, FT);
// Check that the argument values match the function type for this function...
unsigned i = 0;
for (Function::aiterator I = F.abegin(), E = F.aend(); I != E; ++I, ++i)
Assert2(I->getType() == FT->getParamType(i),
"Argument value does not match function argument type!",
I, FT->getParamType(i));
if (!F.isExternal()) {
verifySymbolTable(F.getSymbolTable());
// 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) {
// Ensure that basic blocks have terminators!
Assert1(BB.getTerminator(), "Basic Block does not have terminator!", &BB);
}
void Verifier::visitTerminatorInst(TerminatorInst &I) {
// Ensure that terminators only exist at the end of the basic block.
Assert1(&I == I.getParent()->getTerminator(),
"Terminator found in the middle of a basic block!", I.getParent());
visitInstruction(I);
}
void Verifier::visitReturnInst(ReturnInst &RI) {
Function *F = RI.getParent()->getParent();
if (RI.getNumOperands() == 0)
Assert1(F->getReturnType() == Type::VoidTy,
"Function returns no value, but ret instruction found that does!",
&RI);
else
Assert2(F->getReturnType() == RI.getOperand(0)->getType(),
"Function return type does not match operand "
"type of return inst!", &RI, F->getReturnType());
// Check to make sure that the return value has neccesary properties for
// terminators...
visitTerminatorInst(RI);
}
// visitPHINode - Ensure that a PHI node is well formed.
void Verifier::visitPHINode(PHINode &PN) {
// Ensure that the PHI nodes are all grouped together at the top of the block.
// This can be tested by checking whether the instruction before this is
// either nonexistant (because this is begin()) or is a PHI node. If not,
// then there is some other instruction before a PHI.
Assert2(PN.getPrev() == 0 || isa<PHINode>(PN.getPrev()),
"PHI nodes not grouped at top of basic block!",
&PN, PN.getParent());
// Ensure that PHI nodes have at least one entry!
Assert1(PN.getNumIncomingValues() != 0,
"PHI nodes must have at least one entry. If the block is dead, "
"the PHI should be removed!",
&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);
// Now we go through and check to make sure that if there is more than one
// entry for a particular basic block in this PHI node, that the incoming
// values are all identical.
//
std::vector<std::pair<BasicBlock*, Value*> > Values;
Values.reserve(PN.getNumIncomingValues());
for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i)
Values.push_back(std::make_pair(PN.getIncomingBlock(i),
PN.getIncomingValue(i)));
// Sort the Values vector so that identical basic block entries are adjacent.
std::sort(Values.begin(), Values.end());
// Check for identical basic blocks with differing incoming values...
for (unsigned i = 1, e = PN.getNumIncomingValues(); i < e; ++i)
Assert4(Values[i].first != Values[i-1].first ||
Values[i].second == Values[i-1].second,
"PHI node has multiple entries for the same basic block with "
"different incoming values!", &PN, Values[i].first,
Values[i].second, Values[i-1].second);
visitInstruction(PN);
}
void Verifier::visitCallInst(CallInst &CI) {
Assert1(isa<PointerType>(CI.getOperand(0)->getType()),
"Called function must be a pointer!", &CI);
const PointerType *FPTy = cast<PointerType>(CI.getOperand(0)->getType());
Assert1(isa<FunctionType>(FPTy->getElementType()),
"Called function is not pointer to function type!", &CI);
const FunctionType *FTy = cast<FunctionType>(FPTy->getElementType());
// Verify that the correct number of arguments are being passed
if (FTy->isVarArg())
Assert1(CI.getNumOperands()-1 >= FTy->getNumParams(),
"Called function requires more parameters than were provided!",&CI);
else
Assert1(CI.getNumOperands()-1 == FTy->getNumParams(),
"Incorrect number of arguments passed to called function!", &CI);
// Verify that all arguments to the call match the function type...
for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
Assert2(CI.getOperand(i+1)->getType() == FTy->getParamType(i),
"Call parameter type does not match function signature!",
CI.getOperand(i+1), FTy->getParamType(i));
visitInstruction(CI);
}
// visitBinaryOperator - Check that both arguments to the binary operator are
// of the same type!
//
void Verifier::visitBinaryOperator(BinaryOperator &B) {
Assert1(B.getOperand(0)->getType() == B.getOperand(1)->getType(),
"Both operands to a binary operator are not of the same type!", &B);
// Check that logical operators are only used with integral operands.
if (B.getOpcode() == Instruction::And || B.getOpcode() == Instruction::Or ||
B.getOpcode() == Instruction::Xor) {
Assert1(B.getType()->isIntegral(),
"Logical operators only work with integral types!", &B);
Assert1(B.getType() == B.getOperand(0)->getType(),
"Logical operators must have same type for operands and result!",
&B);
} else if (isa<SetCondInst>(B)) {
// Check that setcc instructions return bool
Assert1(B.getType() == Type::BoolTy,
"setcc instructions must return boolean values!", &B);
} else {
// Arithmetic operators only work on integer or fp values
Assert1(B.getType() == B.getOperand(0)->getType(),
"Arithmetic operators must have same type for operands and result!",
&B);
Assert1(B.getType()->isInteger() || B.getType()->isFloatingPoint(),
"Arithmetic operators must have integer or fp type!", &B);
}
visitInstruction(B);
}
void Verifier::visitShiftInst(ShiftInst &SI) {
Assert1(SI.getType()->isInteger(),
"Shift must return an integer result!", &SI);
Assert1(SI.getType() == SI.getOperand(0)->getType(),
"Shift return type must be same as first operand!", &SI);
Assert1(SI.getOperand(1)->getType() == Type::UByteTy,
"Second operand to shift must be ubyte type!", &SI);
visitInstruction(SI);
}
void Verifier::visitGetElementPtrInst(GetElementPtrInst &GEP) {
const Type *ElTy =
GetElementPtrInst::getIndexedType(GEP.getOperand(0)->getType(),
std::vector<Value*>(GEP.idx_begin(), GEP.idx_end()), true);
Assert1(ElTy, "Invalid indices for GEP pointer type!", &GEP);
Assert2(PointerType::get(ElTy) == GEP.getType(),
"GEP is not of right type for indices!", &GEP, ElTy);
visitInstruction(GEP);
}
void Verifier::visitLoadInst(LoadInst &LI) {
const Type *ElTy =
cast<PointerType>(LI.getOperand(0)->getType())->getElementType();
Assert2(ElTy == LI.getType(),
"Load is not of right type for indices!", &LI, ElTy);
visitInstruction(LI);
}
void Verifier::visitStoreInst(StoreInst &SI) {
const Type *ElTy =
cast<PointerType>(SI.getOperand(1)->getType())->getElementType();
Assert2(ElTy == SI.getOperand(0)->getType(),
"Stored value is not of right type for indices!", &SI, ElTy);
visitInstruction(SI);
}
// verifyInstruction - Verify that an instruction is well formed.
//
void Verifier::visitInstruction(Instruction &I) {
BasicBlock *BB = I.getParent();
Assert1(BB, "Instruction not embedded in basic block!", &I);
// 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);
}
// Check that void typed values don't have names
Assert1(I.getType() != Type::VoidTy || !I.hasName(),
"Instruction has a name, but provides a void value!", &I);
// Check that a definition dominates all of its uses.
//
for (User::use_iterator UI = I.use_begin(), UE = I.use_end();
UI != UE; ++UI) {
Instruction *Use = cast<Instruction>(*UI);
// PHI nodes are more difficult than other nodes because they actually
// "use" the value in the predecessor basic blocks they correspond to.
if (PHINode *PN = dyn_cast<PHINode>(Use)) {
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
if (&I == PN->getIncomingValue(i)) {
// Make sure that I dominates the end of pred(i)
BasicBlock *Pred = PN->getIncomingBlock(i);
// Use must be dominated by by definition unless use is unreachable!
Assert2(DS->dominates(BB, Pred) ||
!DS->dominates(&BB->getParent()->getEntryNode(), Pred),
"Instruction does not dominate all uses!",
&I, PN);
}
} else {
// Use must be dominated by by definition unless use is unreachable!
Assert2(DS->dominates(&I, Use) ||
!DS->dominates(&BB->getParent()->getEntryNode(),Use->getParent()),
"Instruction does not dominate all uses!", &I, Use);
}
}
}
//===----------------------------------------------------------------------===//
// Implement the public interfaces to this file...
//===----------------------------------------------------------------------===//
Pass *createVerifierPass() {
return new Verifier();
}
// verifyFunction - Create
bool verifyFunction(const Function &f) {
Function &F = (Function&)f;
assert(!F.isExternal() && "Cannot verify external functions");
DominatorSet DS;
DS.doInitialization(*F.getParent());
DS.runOnFunction(F);
Verifier V(DS);
V.runOnFunction(F);
DS.doFinalization(*F.getParent());
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) {
PassManager PM;
Verifier *V = new Verifier();
PM.add(V);
PM.run((Module&)M);
return V->Broken;
}