1 | //===-- ModuleUtils.cpp - Functions to manipulate Modules -----------------===// |
2 | // |
3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
4 | // See https://llvm.org/LICENSE.txt for license information. |
5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
6 | // |
7 | //===----------------------------------------------------------------------===// |
8 | // |
9 | // This family of functions perform manipulations on Modules. |
10 | // |
11 | //===----------------------------------------------------------------------===// |
12 | |
13 | #include "llvm/Transforms/Utils/ModuleUtils.h" |
14 | #include "llvm/Analysis/VectorUtils.h" |
15 | #include "llvm/ADT/SmallString.h" |
16 | #include "llvm/IR/DerivedTypes.h" |
17 | #include "llvm/IR/Function.h" |
18 | #include "llvm/IR/IRBuilder.h" |
19 | #include "llvm/IR/MDBuilder.h" |
20 | #include "llvm/IR/Module.h" |
21 | #include "llvm/Support/raw_ostream.h" |
22 | #include "llvm/Support/xxhash.h" |
23 | |
24 | using namespace llvm; |
25 | |
26 | #define DEBUG_TYPE "moduleutils" |
27 | |
28 | static void appendToGlobalArray(StringRef ArrayName, Module &M, Function *F, |
29 | int Priority, Constant *Data) { |
30 | IRBuilder<> IRB(M.getContext()); |
31 | FunctionType *FnTy = FunctionType::get(Result: IRB.getVoidTy(), isVarArg: false); |
32 | |
33 | // Get the current set of static global constructors and add the new ctor |
34 | // to the list. |
35 | SmallVector<Constant *, 16> CurrentCtors; |
36 | StructType *EltTy; |
37 | if (GlobalVariable *GVCtor = M.getNamedGlobal(Name: ArrayName)) { |
38 | EltTy = cast<StructType>(Val: GVCtor->getValueType()->getArrayElementType()); |
39 | if (Constant *Init = GVCtor->getInitializer()) { |
40 | unsigned n = Init->getNumOperands(); |
41 | CurrentCtors.reserve(N: n + 1); |
42 | for (unsigned i = 0; i != n; ++i) |
43 | CurrentCtors.push_back(Elt: cast<Constant>(Val: Init->getOperand(i))); |
44 | } |
45 | GVCtor->eraseFromParent(); |
46 | } else { |
47 | EltTy = StructType::get(elt1: IRB.getInt32Ty(), |
48 | elts: PointerType::get(ElementType: FnTy, AddressSpace: F->getAddressSpace()), |
49 | elts: IRB.getPtrTy()); |
50 | } |
51 | |
52 | // Build a 3 field global_ctor entry. We don't take a comdat key. |
53 | Constant *CSVals[3]; |
54 | CSVals[0] = IRB.getInt32(C: Priority); |
55 | CSVals[1] = F; |
56 | CSVals[2] = Data ? ConstantExpr::getPointerCast(C: Data, Ty: IRB.getPtrTy()) |
57 | : Constant::getNullValue(Ty: IRB.getPtrTy()); |
58 | Constant *RuntimeCtorInit = |
59 | ConstantStruct::get(T: EltTy, V: ArrayRef(CSVals, EltTy->getNumElements())); |
60 | |
61 | CurrentCtors.push_back(Elt: RuntimeCtorInit); |
62 | |
63 | // Create a new initializer. |
64 | ArrayType *AT = ArrayType::get(ElementType: EltTy, NumElements: CurrentCtors.size()); |
65 | Constant *NewInit = ConstantArray::get(T: AT, V: CurrentCtors); |
66 | |
67 | // Create the new global variable and replace all uses of |
68 | // the old global variable with the new one. |
69 | (void)new GlobalVariable(M, NewInit->getType(), false, |
70 | GlobalValue::AppendingLinkage, NewInit, ArrayName); |
71 | } |
72 | |
73 | void llvm::appendToGlobalCtors(Module &M, Function *F, int Priority, Constant *Data) { |
74 | appendToGlobalArray(ArrayName: "llvm.global_ctors" , M, F, Priority, Data); |
75 | } |
76 | |
77 | void llvm::appendToGlobalDtors(Module &M, Function *F, int Priority, Constant *Data) { |
78 | appendToGlobalArray(ArrayName: "llvm.global_dtors" , M, F, Priority, Data); |
79 | } |
80 | |
81 | static void collectUsedGlobals(GlobalVariable *GV, |
82 | SmallSetVector<Constant *, 16> &Init) { |
83 | if (!GV || !GV->hasInitializer()) |
84 | return; |
85 | |
86 | auto *CA = cast<ConstantArray>(Val: GV->getInitializer()); |
87 | for (Use &Op : CA->operands()) |
88 | Init.insert(X: cast<Constant>(Val&: Op)); |
89 | } |
90 | |
91 | static void appendToUsedList(Module &M, StringRef Name, ArrayRef<GlobalValue *> Values) { |
92 | GlobalVariable *GV = M.getGlobalVariable(Name); |
93 | |
94 | SmallSetVector<Constant *, 16> Init; |
95 | collectUsedGlobals(GV, Init); |
96 | if (GV) |
97 | GV->eraseFromParent(); |
98 | |
99 | Type *ArrayEltTy = llvm::PointerType::getUnqual(C&: M.getContext()); |
100 | for (auto *V : Values) |
101 | Init.insert(X: ConstantExpr::getPointerBitCastOrAddrSpaceCast(C: V, Ty: ArrayEltTy)); |
102 | |
103 | if (Init.empty()) |
104 | return; |
105 | |
106 | ArrayType *ATy = ArrayType::get(ElementType: ArrayEltTy, NumElements: Init.size()); |
107 | GV = new llvm::GlobalVariable(M, ATy, false, GlobalValue::AppendingLinkage, |
108 | ConstantArray::get(T: ATy, V: Init.getArrayRef()), |
109 | Name); |
110 | GV->setSection("llvm.metadata" ); |
111 | } |
112 | |
113 | void llvm::appendToUsed(Module &M, ArrayRef<GlobalValue *> Values) { |
114 | appendToUsedList(M, Name: "llvm.used" , Values); |
115 | } |
116 | |
117 | void llvm::appendToCompilerUsed(Module &M, ArrayRef<GlobalValue *> Values) { |
118 | appendToUsedList(M, Name: "llvm.compiler.used" , Values); |
119 | } |
120 | |
121 | static void removeFromUsedList(Module &M, StringRef Name, |
122 | function_ref<bool(Constant *)> ShouldRemove) { |
123 | GlobalVariable *GV = M.getNamedGlobal(Name); |
124 | if (!GV) |
125 | return; |
126 | |
127 | SmallSetVector<Constant *, 16> Init; |
128 | collectUsedGlobals(GV, Init); |
129 | |
130 | Type *ArrayEltTy = cast<ArrayType>(Val: GV->getValueType())->getElementType(); |
131 | |
132 | SmallVector<Constant *, 16> NewInit; |
133 | for (Constant *MaybeRemoved : Init) { |
134 | if (!ShouldRemove(MaybeRemoved->stripPointerCasts())) |
135 | NewInit.push_back(Elt: MaybeRemoved); |
136 | } |
137 | |
138 | if (!NewInit.empty()) { |
139 | ArrayType *ATy = ArrayType::get(ElementType: ArrayEltTy, NumElements: NewInit.size()); |
140 | GlobalVariable *NewGV = |
141 | new GlobalVariable(M, ATy, false, GlobalValue::AppendingLinkage, |
142 | ConstantArray::get(T: ATy, V: NewInit), "" , GV, |
143 | GV->getThreadLocalMode(), GV->getAddressSpace()); |
144 | NewGV->setSection(GV->getSection()); |
145 | NewGV->takeName(V: GV); |
146 | } |
147 | |
148 | GV->eraseFromParent(); |
149 | } |
150 | |
151 | void llvm::removeFromUsedLists(Module &M, |
152 | function_ref<bool(Constant *)> ShouldRemove) { |
153 | removeFromUsedList(M, Name: "llvm.used" , ShouldRemove); |
154 | removeFromUsedList(M, Name: "llvm.compiler.used" , ShouldRemove); |
155 | } |
156 | |
157 | void llvm::setKCFIType(Module &M, Function &F, StringRef MangledType) { |
158 | if (!M.getModuleFlag(Key: "kcfi" )) |
159 | return; |
160 | // Matches CodeGenModule::CreateKCFITypeId in Clang. |
161 | LLVMContext &Ctx = M.getContext(); |
162 | MDBuilder MDB(Ctx); |
163 | F.setMetadata( |
164 | KindID: LLVMContext::MD_kcfi_type, |
165 | Node: MDNode::get(Context&: Ctx, MDs: MDB.createConstant(C: ConstantInt::get( |
166 | Ty: Type::getInt32Ty(C&: Ctx), |
167 | V: static_cast<uint32_t>(xxHash64(Data: MangledType)))))); |
168 | // If the module was compiled with -fpatchable-function-entry, ensure |
169 | // we use the same patchable-function-prefix. |
170 | if (auto *MD = mdconst::extract_or_null<ConstantInt>( |
171 | MD: M.getModuleFlag(Key: "kcfi-offset" ))) { |
172 | if (unsigned Offset = MD->getZExtValue()) |
173 | F.addFnAttr(Kind: "patchable-function-prefix" , Val: std::to_string(val: Offset)); |
174 | } |
175 | } |
176 | |
177 | FunctionCallee llvm::declareSanitizerInitFunction(Module &M, StringRef InitName, |
178 | ArrayRef<Type *> InitArgTypes, |
179 | bool Weak) { |
180 | assert(!InitName.empty() && "Expected init function name" ); |
181 | auto *VoidTy = Type::getVoidTy(C&: M.getContext()); |
182 | auto *FnTy = FunctionType::get(Result: VoidTy, Params: InitArgTypes, isVarArg: false); |
183 | auto FnCallee = M.getOrInsertFunction(Name: InitName, T: FnTy); |
184 | auto *Fn = cast<Function>(Val: FnCallee.getCallee()); |
185 | if (Weak && Fn->isDeclaration()) |
186 | Fn->setLinkage(Function::ExternalWeakLinkage); |
187 | return FnCallee; |
188 | } |
189 | |
190 | Function *llvm::createSanitizerCtor(Module &M, StringRef CtorName) { |
191 | Function *Ctor = Function::createWithDefaultAttr( |
192 | Ty: FunctionType::get(Result: Type::getVoidTy(C&: M.getContext()), isVarArg: false), |
193 | Linkage: GlobalValue::InternalLinkage, AddrSpace: M.getDataLayout().getProgramAddressSpace(), |
194 | N: CtorName, M: &M); |
195 | Ctor->addFnAttr(Attribute::NoUnwind); |
196 | setKCFIType(M, F&: *Ctor, MangledType: "_ZTSFvvE" ); // void (*)(void) |
197 | BasicBlock *CtorBB = BasicBlock::Create(Context&: M.getContext(), Name: "" , Parent: Ctor); |
198 | ReturnInst::Create(C&: M.getContext(), InsertAtEnd: CtorBB); |
199 | // Ensure Ctor cannot be discarded, even if in a comdat. |
200 | appendToUsed(M, Values: {Ctor}); |
201 | return Ctor; |
202 | } |
203 | |
204 | std::pair<Function *, FunctionCallee> llvm::createSanitizerCtorAndInitFunctions( |
205 | Module &M, StringRef CtorName, StringRef InitName, |
206 | ArrayRef<Type *> InitArgTypes, ArrayRef<Value *> InitArgs, |
207 | StringRef VersionCheckName, bool Weak) { |
208 | assert(!InitName.empty() && "Expected init function name" ); |
209 | assert(InitArgs.size() == InitArgTypes.size() && |
210 | "Sanitizer's init function expects different number of arguments" ); |
211 | FunctionCallee InitFunction = |
212 | declareSanitizerInitFunction(M, InitName, InitArgTypes, Weak); |
213 | Function *Ctor = createSanitizerCtor(M, CtorName); |
214 | IRBuilder<> IRB(M.getContext()); |
215 | |
216 | BasicBlock *RetBB = &Ctor->getEntryBlock(); |
217 | if (Weak) { |
218 | RetBB->setName("ret" ); |
219 | auto *EntryBB = BasicBlock::Create(Context&: M.getContext(), Name: "entry" , Parent: Ctor, InsertBefore: RetBB); |
220 | auto *CallInitBB = |
221 | BasicBlock::Create(Context&: M.getContext(), Name: "callfunc" , Parent: Ctor, InsertBefore: RetBB); |
222 | auto *InitFn = cast<Function>(Val: InitFunction.getCallee()); |
223 | auto *InitFnPtr = |
224 | PointerType::get(ElementType: InitFn->getType(), AddressSpace: InitFn->getAddressSpace()); |
225 | IRB.SetInsertPoint(EntryBB); |
226 | Value *InitNotNull = |
227 | IRB.CreateICmpNE(LHS: InitFn, RHS: ConstantPointerNull::get(T: InitFnPtr)); |
228 | IRB.CreateCondBr(Cond: InitNotNull, True: CallInitBB, False: RetBB); |
229 | IRB.SetInsertPoint(CallInitBB); |
230 | } else { |
231 | IRB.SetInsertPoint(RetBB->getTerminator()); |
232 | } |
233 | |
234 | IRB.CreateCall(Callee: InitFunction, Args: InitArgs); |
235 | if (!VersionCheckName.empty()) { |
236 | FunctionCallee VersionCheckFunction = M.getOrInsertFunction( |
237 | Name: VersionCheckName, T: FunctionType::get(Result: IRB.getVoidTy(), Params: {}, isVarArg: false), |
238 | AttributeList: AttributeList()); |
239 | IRB.CreateCall(Callee: VersionCheckFunction, Args: {}); |
240 | } |
241 | |
242 | if (Weak) |
243 | IRB.CreateBr(Dest: RetBB); |
244 | |
245 | return std::make_pair(x&: Ctor, y&: InitFunction); |
246 | } |
247 | |
248 | std::pair<Function *, FunctionCallee> |
249 | llvm::getOrCreateSanitizerCtorAndInitFunctions( |
250 | Module &M, StringRef CtorName, StringRef InitName, |
251 | ArrayRef<Type *> InitArgTypes, ArrayRef<Value *> InitArgs, |
252 | function_ref<void(Function *, FunctionCallee)> FunctionsCreatedCallback, |
253 | StringRef VersionCheckName, bool Weak) { |
254 | assert(!CtorName.empty() && "Expected ctor function name" ); |
255 | |
256 | if (Function *Ctor = M.getFunction(Name: CtorName)) |
257 | // FIXME: Sink this logic into the module, similar to the handling of |
258 | // globals. This will make moving to a concurrent model much easier. |
259 | if (Ctor->arg_empty() || |
260 | Ctor->getReturnType() == Type::getVoidTy(C&: M.getContext())) |
261 | return {Ctor, |
262 | declareSanitizerInitFunction(M, InitName, InitArgTypes, Weak)}; |
263 | |
264 | Function *Ctor; |
265 | FunctionCallee InitFunction; |
266 | std::tie(args&: Ctor, args&: InitFunction) = llvm::createSanitizerCtorAndInitFunctions( |
267 | M, CtorName, InitName, InitArgTypes, InitArgs, VersionCheckName, Weak); |
268 | FunctionsCreatedCallback(Ctor, InitFunction); |
269 | return std::make_pair(x&: Ctor, y&: InitFunction); |
270 | } |
271 | |
272 | void llvm::filterDeadComdatFunctions( |
273 | SmallVectorImpl<Function *> &DeadComdatFunctions) { |
274 | SmallPtrSet<Function *, 32> MaybeDeadFunctions; |
275 | SmallPtrSet<Comdat *, 32> MaybeDeadComdats; |
276 | for (Function *F : DeadComdatFunctions) { |
277 | MaybeDeadFunctions.insert(Ptr: F); |
278 | if (Comdat *C = F->getComdat()) |
279 | MaybeDeadComdats.insert(Ptr: C); |
280 | } |
281 | |
282 | // Find comdats for which all users are dead now. |
283 | SmallPtrSet<Comdat *, 32> DeadComdats; |
284 | for (Comdat *C : MaybeDeadComdats) { |
285 | auto IsUserDead = [&](GlobalObject *GO) { |
286 | auto *F = dyn_cast<Function>(Val: GO); |
287 | return F && MaybeDeadFunctions.contains(Ptr: F); |
288 | }; |
289 | if (all_of(Range: C->getUsers(), P: IsUserDead)) |
290 | DeadComdats.insert(Ptr: C); |
291 | } |
292 | |
293 | // Only keep functions which have no comdat or a dead comdat. |
294 | erase_if(C&: DeadComdatFunctions, P: [&](Function *F) { |
295 | Comdat *C = F->getComdat(); |
296 | return C && !DeadComdats.contains(Ptr: C); |
297 | }); |
298 | } |
299 | |
300 | std::string llvm::getUniqueModuleId(Module *M) { |
301 | MD5 Md5; |
302 | bool ExportsSymbols = false; |
303 | auto AddGlobal = [&](GlobalValue &GV) { |
304 | if (GV.isDeclaration() || GV.getName().starts_with(Prefix: "llvm." ) || |
305 | !GV.hasExternalLinkage() || GV.hasComdat()) |
306 | return; |
307 | ExportsSymbols = true; |
308 | Md5.update(Str: GV.getName()); |
309 | Md5.update(Data: ArrayRef<uint8_t>{0}); |
310 | }; |
311 | |
312 | for (auto &F : *M) |
313 | AddGlobal(F); |
314 | for (auto &GV : M->globals()) |
315 | AddGlobal(GV); |
316 | for (auto &GA : M->aliases()) |
317 | AddGlobal(GA); |
318 | for (auto &IF : M->ifuncs()) |
319 | AddGlobal(IF); |
320 | |
321 | if (!ExportsSymbols) |
322 | return "" ; |
323 | |
324 | MD5::MD5Result R; |
325 | Md5.final(Result&: R); |
326 | |
327 | SmallString<32> Str; |
328 | MD5::stringifyResult(Result&: R, Str); |
329 | return ("." + Str).str(); |
330 | } |
331 | |
332 | void llvm::embedBufferInModule(Module &M, MemoryBufferRef Buf, |
333 | StringRef SectionName, Align Alignment) { |
334 | // Embed the memory buffer into the module. |
335 | Constant *ModuleConstant = ConstantDataArray::get( |
336 | Context&: M.getContext(), Elts: ArrayRef(Buf.getBufferStart(), Buf.getBufferSize())); |
337 | GlobalVariable *GV = new GlobalVariable( |
338 | M, ModuleConstant->getType(), true, GlobalValue::PrivateLinkage, |
339 | ModuleConstant, "llvm.embedded.object" ); |
340 | GV->setSection(SectionName); |
341 | GV->setAlignment(Alignment); |
342 | |
343 | LLVMContext &Ctx = M.getContext(); |
344 | NamedMDNode *MD = M.getOrInsertNamedMetadata(Name: "llvm.embedded.objects" ); |
345 | Metadata *MDVals[] = {ConstantAsMetadata::get(C: GV), |
346 | MDString::get(Context&: Ctx, Str: SectionName)}; |
347 | |
348 | MD->addOperand(M: llvm::MDNode::get(Context&: Ctx, MDs: MDVals)); |
349 | GV->setMetadata(KindID: LLVMContext::MD_exclude, Node: llvm::MDNode::get(Context&: Ctx, MDs: {})); |
350 | |
351 | appendToCompilerUsed(M, Values: GV); |
352 | } |
353 | |
354 | bool llvm::lowerGlobalIFuncUsersAsGlobalCtor( |
355 | Module &M, ArrayRef<GlobalIFunc *> FilteredIFuncsToLower) { |
356 | SmallVector<GlobalIFunc *, 32> AllIFuncs; |
357 | ArrayRef<GlobalIFunc *> IFuncsToLower = FilteredIFuncsToLower; |
358 | if (FilteredIFuncsToLower.empty()) { // Default to lowering all ifuncs |
359 | for (GlobalIFunc &GI : M.ifuncs()) |
360 | AllIFuncs.push_back(Elt: &GI); |
361 | IFuncsToLower = AllIFuncs; |
362 | } |
363 | |
364 | bool UnhandledUsers = false; |
365 | LLVMContext &Ctx = M.getContext(); |
366 | const DataLayout &DL = M.getDataLayout(); |
367 | |
368 | PointerType *TableEntryTy = |
369 | PointerType::get(C&: Ctx, AddressSpace: DL.getProgramAddressSpace()); |
370 | |
371 | ArrayType *FuncPtrTableTy = |
372 | ArrayType::get(ElementType: TableEntryTy, NumElements: IFuncsToLower.size()); |
373 | |
374 | Align PtrAlign = DL.getABITypeAlign(Ty: TableEntryTy); |
375 | |
376 | // Create a global table of function pointers we'll initialize in a global |
377 | // constructor. |
378 | auto *FuncPtrTable = new GlobalVariable( |
379 | M, FuncPtrTableTy, false, GlobalValue::InternalLinkage, |
380 | PoisonValue::get(T: FuncPtrTableTy), "" , nullptr, |
381 | GlobalVariable::NotThreadLocal, DL.getDefaultGlobalsAddressSpace()); |
382 | FuncPtrTable->setAlignment(PtrAlign); |
383 | |
384 | // Create a function to initialize the function pointer table. |
385 | Function *NewCtor = Function::Create( |
386 | Ty: FunctionType::get(Result: Type::getVoidTy(C&: Ctx), isVarArg: false), Linkage: Function::InternalLinkage, |
387 | AddrSpace: DL.getProgramAddressSpace(), N: "" , M: &M); |
388 | |
389 | BasicBlock *BB = BasicBlock::Create(Context&: Ctx, Name: "" , Parent: NewCtor); |
390 | IRBuilder<> InitBuilder(BB); |
391 | |
392 | size_t TableIndex = 0; |
393 | for (GlobalIFunc *GI : IFuncsToLower) { |
394 | Function *ResolvedFunction = GI->getResolverFunction(); |
395 | |
396 | // We don't know what to pass to a resolver function taking arguments |
397 | // |
398 | // FIXME: Is this even valid? clang and gcc don't complain but this |
399 | // probably should be invalid IR. We could just pass through undef. |
400 | if (!std::empty(cont: ResolvedFunction->getFunctionType()->params())) { |
401 | LLVM_DEBUG(dbgs() << "Not lowering ifunc resolver function " |
402 | << ResolvedFunction->getName() << " with parameters\n" ); |
403 | UnhandledUsers = true; |
404 | continue; |
405 | } |
406 | |
407 | // Initialize the function pointer table. |
408 | CallInst *ResolvedFunc = InitBuilder.CreateCall(Callee: ResolvedFunction); |
409 | Value *Casted = InitBuilder.CreatePointerCast(V: ResolvedFunc, DestTy: TableEntryTy); |
410 | Constant *GEP = cast<Constant>(Val: InitBuilder.CreateConstInBoundsGEP2_32( |
411 | Ty: FuncPtrTableTy, Ptr: FuncPtrTable, Idx0: 0, Idx1: TableIndex++)); |
412 | InitBuilder.CreateAlignedStore(Val: Casted, Ptr: GEP, Align: PtrAlign); |
413 | |
414 | // Update all users to load a pointer from the global table. |
415 | for (User *User : make_early_inc_range(Range: GI->users())) { |
416 | Instruction *UserInst = dyn_cast<Instruction>(Val: User); |
417 | if (!UserInst) { |
418 | // TODO: Should handle constantexpr casts in user instructions. Probably |
419 | // can't do much about constant initializers. |
420 | UnhandledUsers = true; |
421 | continue; |
422 | } |
423 | |
424 | IRBuilder<> UseBuilder(UserInst); |
425 | LoadInst *ResolvedTarget = |
426 | UseBuilder.CreateAlignedLoad(Ty: TableEntryTy, Ptr: GEP, Align: PtrAlign); |
427 | Value *ResolvedCast = |
428 | UseBuilder.CreatePointerCast(V: ResolvedTarget, DestTy: GI->getType()); |
429 | UserInst->replaceUsesOfWith(From: GI, To: ResolvedCast); |
430 | } |
431 | |
432 | // If we handled all users, erase the ifunc. |
433 | if (GI->use_empty()) |
434 | GI->eraseFromParent(); |
435 | } |
436 | |
437 | InitBuilder.CreateRetVoid(); |
438 | |
439 | PointerType *ConstantDataTy = PointerType::get(C&: Ctx, AddressSpace: 0); |
440 | |
441 | // TODO: Is this the right priority? Probably should be before any other |
442 | // constructors? |
443 | const int Priority = 10; |
444 | appendToGlobalCtors(M, F: NewCtor, Priority, |
445 | Data: ConstantPointerNull::get(T: ConstantDataTy)); |
446 | return UnhandledUsers; |
447 | } |
448 | |