1 //===- SanitizerStats.cpp - Sanitizer statistics gathering ----------------===// 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 // Implements code generation for sanitizer statistics gathering. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "llvm/Transforms/Utils/SanitizerStats.h" 14 #include "llvm/IR/Constants.h" 15 #include "llvm/IR/DerivedTypes.h" 16 #include "llvm/IR/GlobalVariable.h" 17 #include "llvm/IR/IRBuilder.h" 18 #include "llvm/IR/Module.h" 19 #include "llvm/Transforms/Utils/ModuleUtils.h" 20 21 using namespace llvm; 22 23 SanitizerStatReport::SanitizerStatReport(Module *M) : M(M) { 24 StatTy = ArrayType::get(PointerType::getUnqual(M->getContext()), 2); 25 EmptyModuleStatsTy = makeModuleStatsTy(); 26 27 ModuleStatsGV = new GlobalVariable(*M, EmptyModuleStatsTy, false, 28 GlobalValue::InternalLinkage, nullptr); 29 } 30 31 ArrayType *SanitizerStatReport::makeModuleStatsArrayTy() { 32 return ArrayType::get(StatTy, Inits.size()); 33 } 34 35 StructType *SanitizerStatReport::makeModuleStatsTy() { 36 return StructType::get(M->getContext(), 37 {PointerType::getUnqual(M->getContext()), 38 Type::getInt32Ty(M->getContext()), 39 makeModuleStatsArrayTy()}); 40 } 41 42 void SanitizerStatReport::create(IRBuilder<> &B, SanitizerStatKind SK) { 43 Function *F = B.GetInsertBlock()->getParent(); 44 Module *M = F->getParent(); 45 PointerType *PtrTy = B.getPtrTy(); 46 IntegerType *IntPtrTy = B.getIntPtrTy(M->getDataLayout()); 47 ArrayType *StatTy = ArrayType::get(PtrTy, 2); 48 49 Inits.push_back(ConstantArray::get( 50 StatTy, 51 {Constant::getNullValue(PtrTy), 52 ConstantExpr::getIntToPtr( 53 ConstantInt::get(IntPtrTy, uint64_t(SK) << (IntPtrTy->getBitWidth() - 54 kSanitizerStatKindBits)), 55 PtrTy)})); 56 57 FunctionType *StatReportTy = FunctionType::get(B.getVoidTy(), PtrTy, false); 58 FunctionCallee StatReport = 59 M->getOrInsertFunction("__sanitizer_stat_report", StatReportTy); 60 61 auto InitAddr = ConstantExpr::getGetElementPtr( 62 EmptyModuleStatsTy, ModuleStatsGV, 63 ArrayRef<Constant *>{ 64 ConstantInt::get(IntPtrTy, 0), ConstantInt::get(B.getInt32Ty(), 2), 65 ConstantInt::get(IntPtrTy, Inits.size() - 1), 66 }); 67 B.CreateCall(StatReport, InitAddr); 68 } 69 70 void SanitizerStatReport::finish() { 71 if (Inits.empty()) { 72 ModuleStatsGV->eraseFromParent(); 73 return; 74 } 75 76 PointerType *Int8PtrTy = PointerType::getUnqual(M->getContext()); 77 IntegerType *Int32Ty = Type::getInt32Ty(M->getContext()); 78 Type *VoidTy = Type::getVoidTy(M->getContext()); 79 80 // Create a new ModuleStatsGV to replace the old one. We can't just set the 81 // old one's initializer because its type is different. 82 auto NewModuleStatsGV = new GlobalVariable( 83 *M, makeModuleStatsTy(), false, GlobalValue::InternalLinkage, 84 ConstantStruct::getAnon( 85 {Constant::getNullValue(Int8PtrTy), 86 ConstantInt::get(Int32Ty, Inits.size()), 87 ConstantArray::get(makeModuleStatsArrayTy(), Inits)})); 88 ModuleStatsGV->replaceAllUsesWith(NewModuleStatsGV); 89 ModuleStatsGV->eraseFromParent(); 90 91 // Create a global constructor to register NewModuleStatsGV. 92 auto F = Function::Create(FunctionType::get(VoidTy, false), 93 GlobalValue::InternalLinkage, "", M); 94 auto BB = BasicBlock::Create(M->getContext(), "", F); 95 IRBuilder<> B(BB); 96 97 FunctionType *StatInitTy = FunctionType::get(VoidTy, Int8PtrTy, false); 98 FunctionCallee StatInit = 99 M->getOrInsertFunction("__sanitizer_stat_init", StatInitTy); 100 101 B.CreateCall(StatInit, NewModuleStatsGV); 102 B.CreateRetVoid(); 103 104 appendToGlobalCtors(*M, F, 0); 105 } 106