static uint64_t sizeOf(llvm::Type *ty, llvm::DataLayout &DL) { if (ty->isSized()) return DL.getTypeStoreSize(ty); else return 0; }
// // 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; }