//
// Method: runOnModule()
//
// Description:
// Entry point for this LLVM pass.
// If a function returns a struct, make it return
// a pointer to the struct.
//
// Inputs:
// M - A reference to the LLVM module to transform
//
// Outputs:
// M - The transformed LLVM module.
//
// Return value:
// true - The module was modified.
// false - The module was not modified.
//
bool StructRet::runOnModule(Module& M) {
const llvm::DataLayout targetData(&M);
std::vector<Function*> worklist;
for (Module::iterator I = M.begin(); I != M.end(); ++I)
if (!I->mayBeOverridden()) {
if(I->hasAddressTaken())
continue;
if(I->getReturnType()->isStructTy()) {
worklist.push_back(I);
}
}
while(!worklist.empty()) {
Function *F = worklist.back();
worklist.pop_back();
Type *NewArgType = F->getReturnType()->getPointerTo();
// Construct the new Type
std::vector<Type*>TP;
TP.push_back(NewArgType);
for (Function::arg_iterator ii = F->arg_begin(), ee = F->arg_end();
ii != ee; ++ii) {
TP.push_back(ii->getType());
}
FunctionType *NFTy = FunctionType::get(F->getReturnType(), TP, F->isVarArg());
// Create the new function body and insert it into the module.
Function *NF = Function::Create(NFTy,
F->getLinkage(),
F->getName(), &M);
ValueToValueMapTy ValueMap;
Function::arg_iterator NI = NF->arg_begin();
NI->setName("ret");
++NI;
for (Function::arg_iterator II = F->arg_begin(); II != F->arg_end(); ++II, ++NI) {
ValueMap[II] = NI;
NI->setName(II->getName());
AttributeSet attrs = F->getAttributes().getParamAttributes(II->getArgNo() + 1);
if (!attrs.isEmpty())
NI->addAttr(attrs);
}
// Perform the cloning.
SmallVector<ReturnInst*,100> Returns;
if (!F->isDeclaration())
CloneFunctionInto(NF, F, ValueMap, false, Returns);
std::vector<Value*> fargs;
for(Function::arg_iterator ai = NF->arg_begin(),
ae= NF->arg_end(); ai != ae; ++ai) {
fargs.push_back(ai);
}
NF->setAttributes(NF->getAttributes().addAttributes(
M.getContext(), 0, F->getAttributes().getRetAttributes()));
NF->setAttributes(NF->getAttributes().addAttributes(
M.getContext(), ~0, F->getAttributes().getFnAttributes()));
for (Function::iterator B = NF->begin(), FE = NF->end(); B != FE; ++B) {
for (BasicBlock::iterator I = B->begin(), BE = B->end(); I != BE;) {
ReturnInst * RI = dyn_cast<ReturnInst>(I++);
if(!RI)
continue;
LoadInst *LI = dyn_cast<LoadInst>(RI->getOperand(0));
assert(LI && "Return should be preceded by a load instruction");
IRBuilder<> Builder(RI);
Builder.CreateMemCpy(fargs.at(0),
LI->getPointerOperand(),
targetData.getTypeStoreSize(LI->getType()),
targetData.getPrefTypeAlignment(LI->getType()));
}
}
for(Value::use_iterator ui = F->use_begin(), ue = F->use_end();
ui != ue; ) {
CallInst *CI = dyn_cast<CallInst>(*ui++);
if(!CI)
continue;
if(CI->getCalledFunction() != F)
continue;
if(CI->hasByValArgument())
continue;
AllocaInst *AllocaNew = new AllocaInst(F->getReturnType(), 0, "", CI);
SmallVector<Value*, 8> Args;
//this should probably be done in a different manner
AttributeSet NewCallPAL=AttributeSet();
// Get the initial attributes of the call
AttributeSet CallPAL = CI->getAttributes();
AttributeSet RAttrs = CallPAL.getRetAttributes();
AttributeSet FnAttrs = CallPAL.getFnAttributes();
if (!RAttrs.isEmpty())
NewCallPAL=NewCallPAL.addAttributes(F->getContext(),0, RAttrs);
Args.push_back(AllocaNew);
for(unsigned j = 0; j < CI->getNumOperands()-1; j++) {
Args.push_back(CI->getOperand(j));
// position in the NewCallPAL
AttributeSet Attrs = CallPAL.getParamAttributes(j);
if (!Attrs.isEmpty())
NewCallPAL=NewCallPAL.addAttributes(F->getContext(),Args.size(), Attrs);
}
// Create the new attributes vec.
if (!FnAttrs.isEmpty())
NewCallPAL=NewCallPAL.addAttributes(F->getContext(),~0, FnAttrs);
CallInst *CallI = CallInst::Create(NF, Args, "", CI);
CallI->setCallingConv(CI->getCallingConv());
CallI->setAttributes(NewCallPAL);
LoadInst *LI = new LoadInst(AllocaNew, "", CI);
CI->replaceAllUsesWith(LI);
CI->eraseFromParent();
}
if(F->use_empty())
F->eraseFromParent();
}
return true;
}
/// CleanupAndPrepareModules - Get the specified modules ready for code
/// generator testing.
///
static void CleanupAndPrepareModules(BugDriver &BD, Module *&Test,
Module *Safe) {
// Clean up the modules, removing extra cruft that we don't need anymore...
Test = BD.performFinalCleanups(Test);
// If we are executing the JIT, we have several nasty issues to take care of.
if (!BD.isExecutingJIT()) return;
// First, if the main function is in the Safe module, we must add a stub to
// the Test module to call into it. Thus, we create a new function `main'
// which just calls the old one.
if (Function *oldMain = Safe->getFunction("main"))
if (!oldMain->isDeclaration()) {
// Rename it
oldMain->setName("llvm_bugpoint_old_main");
// Create a NEW `main' function with same type in the test module.
Function *newMain = Function::Create(oldMain->getFunctionType(),
GlobalValue::ExternalLinkage,
"main", Test);
// Create an `oldmain' prototype in the test module, which will
// corresponds to the real main function in the same module.
Function *oldMainProto = Function::Create(oldMain->getFunctionType(),
GlobalValue::ExternalLinkage,
oldMain->getName(), Test);
// Set up and remember the argument list for the main function.
std::vector<Value*> args;
for (Function::arg_iterator
I = newMain->arg_begin(), E = newMain->arg_end(),
OI = oldMain->arg_begin(); I != E; ++I, ++OI) {
I->setName(OI->getName()); // Copy argument names from oldMain
args.push_back(I);
}
// Call the old main function and return its result
BasicBlock *BB = BasicBlock::Create(Safe->getContext(), "entry", newMain);
CallInst *call = CallInst::Create(oldMainProto, args.begin(), args.end(),
"", BB);
// If the type of old function wasn't void, return value of call
ReturnInst::Create(Safe->getContext(), call, BB);
}
// The second nasty issue we must deal with in the JIT is that the Safe
// module cannot directly reference any functions defined in the test
// module. Instead, we use a JIT API call to dynamically resolve the
// symbol.
// Add the resolver to the Safe module.
// Prototype: void *getPointerToNamedFunction(const char* Name)
Constant *resolverFunc =
Safe->getOrInsertFunction("getPointerToNamedFunction",
Type::getInt8PtrTy(Safe->getContext()),
Type::getInt8PtrTy(Safe->getContext()),
(Type *)0);
// Use the function we just added to get addresses of functions we need.
for (Module::iterator F = Safe->begin(), E = Safe->end(); F != E; ++F) {
if (F->isDeclaration() && !F->use_empty() && &*F != resolverFunc &&
!F->isIntrinsic() /* ignore intrinsics */) {
Function *TestFn = Test->getFunction(F->getName());
// Don't forward functions which are external in the test module too.
if (TestFn && !TestFn->isDeclaration()) {
// 1. Add a string constant with its name to the global file
Constant *InitArray = ConstantArray::get(F->getContext(), F->getName());
GlobalVariable *funcName =
new GlobalVariable(*Safe, InitArray->getType(), true /*isConstant*/,
GlobalValue::InternalLinkage, InitArray,
F->getName() + "_name");
// 2. Use `GetElementPtr *funcName, 0, 0' to convert the string to an
// sbyte* so it matches the signature of the resolver function.
// GetElementPtr *funcName, ulong 0, ulong 0
std::vector<Constant*> GEPargs(2,
Constant::getNullValue(Type::getInt32Ty(F->getContext())));
Value *GEP =
ConstantExpr::getGetElementPtr(funcName, &GEPargs[0], 2);
std::vector<Value*> ResolverArgs;
ResolverArgs.push_back(GEP);
// Rewrite uses of F in global initializers, etc. to uses of a wrapper
// function that dynamically resolves the calls to F via our JIT API
if (!F->use_empty()) {
// Create a new global to hold the cached function pointer.
Constant *NullPtr = ConstantPointerNull::get(F->getType());
GlobalVariable *Cache =
new GlobalVariable(*F->getParent(), F->getType(),
false, GlobalValue::InternalLinkage,
NullPtr,F->getName()+".fpcache");
// Construct a new stub function that will re-route calls to F
const FunctionType *FuncTy = F->getFunctionType();
Function *FuncWrapper = Function::Create(FuncTy,
GlobalValue::InternalLinkage,
F->getName() + "_wrapper",
F->getParent());
BasicBlock *EntryBB = BasicBlock::Create(F->getContext(),
"entry", FuncWrapper);
BasicBlock *DoCallBB = BasicBlock::Create(F->getContext(),
"usecache", FuncWrapper);
BasicBlock *LookupBB = BasicBlock::Create(F->getContext(),
"lookupfp", FuncWrapper);
// Check to see if we already looked up the value.
Value *CachedVal = new LoadInst(Cache, "fpcache", EntryBB);
Value *IsNull = new ICmpInst(*EntryBB, ICmpInst::ICMP_EQ, CachedVal,
NullPtr, "isNull");
BranchInst::Create(LookupBB, DoCallBB, IsNull, EntryBB);
// Resolve the call to function F via the JIT API:
//
// call resolver(GetElementPtr...)
CallInst *Resolver =
CallInst::Create(resolverFunc, ResolverArgs.begin(),
ResolverArgs.end(), "resolver", LookupBB);
// Cast the result from the resolver to correctly-typed function.
CastInst *CastedResolver =
new BitCastInst(Resolver,
PointerType::getUnqual(F->getFunctionType()),
"resolverCast", LookupBB);
// Save the value in our cache.
new StoreInst(CastedResolver, Cache, LookupBB);
BranchInst::Create(DoCallBB, LookupBB);
PHINode *FuncPtr = PHINode::Create(NullPtr->getType(),
"fp", DoCallBB);
FuncPtr->addIncoming(CastedResolver, LookupBB);
FuncPtr->addIncoming(CachedVal, EntryBB);
// Save the argument list.
std::vector<Value*> Args;
for (Function::arg_iterator i = FuncWrapper->arg_begin(),
e = FuncWrapper->arg_end(); i != e; ++i)
Args.push_back(i);
// Pass on the arguments to the real function, return its result
if (F->getReturnType()->isVoidTy()) {
CallInst::Create(FuncPtr, Args.begin(), Args.end(), "", DoCallBB);
ReturnInst::Create(F->getContext(), DoCallBB);
} else {
CallInst *Call = CallInst::Create(FuncPtr, Args.begin(), Args.end(),
"retval", DoCallBB);
ReturnInst::Create(F->getContext(),Call, DoCallBB);
}
// Use the wrapper function instead of the old function
F->replaceAllUsesWith(FuncWrapper);
}
}
}
}
if (verifyModule(*Test) || verifyModule(*Safe)) {
errs() << "Bugpoint has a bug, which corrupted a module!!\n";
abort();
}
}
bool
StdLibDataStructures::runOnModule (Module &M) {
//
// Get the results from the local pass.
//
init (&getAnalysis<LocalDataStructures>(), true, true, false, false);
AllocWrappersAnalysis = &getAnalysis<AllocIdentify>();
//
// Fetch the DSGraphs for all defined functions within the module.
//
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
if (!I->isDeclaration())
getOrCreateGraph(&*I);
//
// Erase direct calls to functions that don't return a pointer and are marked
// with the readnone annotation.
//
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
if (I->isDeclaration() && I->doesNotAccessMemory() &&
!isa<PointerType>(I->getReturnType()))
eraseCallsTo(I);
//
// Erase direct calls to external functions that are not varargs, do not
// return a pointer, and do not take pointers.
//
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
if (I->isDeclaration() && !I->isVarArg() &&
!isa<PointerType>(I->getReturnType())) {
bool hasPtr = false;
for (Function::arg_iterator ii = I->arg_begin(), ee = I->arg_end();
ii != ee;
++ii)
if (isa<PointerType>(ii->getType())) {
hasPtr = true;
break;
}
if (!hasPtr)
eraseCallsTo(I);
}
if(!DisableStdLib) {
//
// Scan through the function summaries and process functions by summary.
//
for (int x = 0; recFuncs[x].name; ++x)
if (Function* F = M.getFunction(recFuncs[x].name))
if (F->isDeclaration()) {
processFunction(x, F);
}
std::set<std::string>::iterator ai = AllocWrappersAnalysis->alloc_begin();
std::set<std::string>::iterator ae = AllocWrappersAnalysis->alloc_end();
int x;
for (x = 0; recFuncs[x].name; ++x) {
if(recFuncs[x].name == std::string("malloc"))
break;
}
for(;ai != ae; ++ai) {
if(Function* F = M.getFunction(*ai))
processFunction(x, F);
}
ai = AllocWrappersAnalysis->dealloc_begin();
ae = AllocWrappersAnalysis->dealloc_end();
for (x = 0; recFuncs[x].name; ++x) {
if(recFuncs[x].name == std::string("free"))
break;
}
for(;ai != ae; ++ai) {
if(Function* F = M.getFunction(*ai))
processFunction(x, F);
}
//
// Merge return values and checked pointer values for SAFECode run-time
// checks.
//
processRuntimeCheck (M, "boundscheck", 2);
processRuntimeCheck (M, "boundscheckui", 2);
processRuntimeCheck (M, "exactcheck2", 1);
processRuntimeCheck (M, "boundscheck_debug", 2);
processRuntimeCheck (M, "boundscheckui_debug", 2);
processRuntimeCheck (M, "exactcheck2_debug", 1);
processRuntimeCheck (M, "pchk_getActualValue", 1);
}
//
// In the Local DSA Pass, we marked nodes passed to/returned from 'StdLib'
// functions as External because, at that point, they were. However, they no
// longer are necessarily External, and we need to update accordingly.
//
GlobalsGraph->maskIncompleteMarkers();
GlobalsGraph->computeExternalFlags(DSGraph::ResetExternal);
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
if (!I->isDeclaration()) {
DSGraph * G = getDSGraph(*I);
unsigned EFlags = 0
| DSGraph::ResetExternal
| DSGraph::DontMarkFormalsExternal
| DSGraph::ProcessCallSites;
G->maskIncompleteMarkers();
G->markIncompleteNodes(DSGraph::MarkFormalArgs
|DSGraph::IgnoreGlobals);
G->computeExternalFlags(EFlags);
DEBUG(G->AssertGraphOK());
}
GlobalsGraph->markIncompleteNodes(DSGraph::MarkFormalArgs
|DSGraph::IgnoreGlobals);
GlobalsGraph->computeExternalFlags(DSGraph::ProcessCallSites);
DEBUG(GlobalsGraph->AssertGraphOK());
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
if (!I->isDeclaration()) {
DSGraph *Graph = getOrCreateGraph(I);
Graph->maskIncompleteMarkers();
cloneGlobalsInto(Graph, DSGraph::DontCloneCallNodes |
DSGraph::DontCloneAuxCallNodes);
Graph->markIncompleteNodes(DSGraph::MarkFormalArgs
|DSGraph::IgnoreGlobals);
}
return false;
}
