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/ADT/Triple.h" 15 #include "llvm/IR/Constants.h" 16 #include "llvm/IR/DerivedTypes.h" 17 #include "llvm/IR/GlobalVariable.h" 18 #include "llvm/IR/IRBuilder.h" 19 #include "llvm/IR/Module.h" 20 #include "llvm/Transforms/Utils/ModuleUtils.h" 21 22 using namespace llvm; 23 24 SanitizerStatReport::SanitizerStatReport(Module *M) : M(M) { 25 StatTy = ArrayType::get(Type::getInt8PtrTy(M->getContext()), 2); 26 EmptyModuleStatsTy = makeModuleStatsTy(); 27 28 ModuleStatsGV = new GlobalVariable(*M, EmptyModuleStatsTy, false, 29 GlobalValue::InternalLinkage, nullptr); 30 } 31 32 ArrayType *SanitizerStatReport::makeModuleStatsArrayTy() { 33 return ArrayType::get(StatTy, Inits.size()); 34 } 35 36 StructType *SanitizerStatReport::makeModuleStatsTy() { 37 return StructType::get(M->getContext(), {Type::getInt8PtrTy(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 *Int8PtrTy = B.getInt8PtrTy(); 46 IntegerType *IntPtrTy = B.getIntPtrTy(M->getDataLayout()); 47 ArrayType *StatTy = ArrayType::get(Int8PtrTy, 2); 48 49 Inits.push_back(ConstantArray::get( 50 StatTy, 51 {Constant::getNullValue(Int8PtrTy), 52 ConstantExpr::getIntToPtr( 53 ConstantInt::get(IntPtrTy, uint64_t(SK) << (IntPtrTy->getBitWidth() - 54 kSanitizerStatKindBits)), 55 Int8PtrTy)})); 56 57 FunctionType *StatReportTy = 58 FunctionType::get(B.getVoidTy(), Int8PtrTy, false); 59 FunctionCallee StatReport = 60 M->getOrInsertFunction("__sanitizer_stat_report", StatReportTy); 61 62 auto InitAddr = ConstantExpr::getGetElementPtr( 63 EmptyModuleStatsTy, ModuleStatsGV, 64 ArrayRef<Constant *>{ 65 ConstantInt::get(IntPtrTy, 0), ConstantInt::get(B.getInt32Ty(), 2), 66 ConstantInt::get(IntPtrTy, Inits.size() - 1), 67 }); 68 B.CreateCall(StatReport, ConstantExpr::getBitCast(InitAddr, Int8PtrTy)); 69 } 70 71 void SanitizerStatReport::finish() { 72 if (Inits.empty()) { 73 ModuleStatsGV->eraseFromParent(); 74 return; 75 } 76 77 PointerType *Int8PtrTy = Type::getInt8PtrTy(M->getContext()); 78 IntegerType *Int32Ty = Type::getInt32Ty(M->getContext()); 79 Type *VoidTy = Type::getVoidTy(M->getContext()); 80 81 // Create a new ModuleStatsGV to replace the old one. We can't just set the 82 // old one's initializer because its type is different. 83 auto NewModuleStatsGV = new GlobalVariable( 84 *M, makeModuleStatsTy(), false, GlobalValue::InternalLinkage, 85 ConstantStruct::getAnon( 86 {Constant::getNullValue(Int8PtrTy), 87 ConstantInt::get(Int32Ty, Inits.size()), 88 ConstantArray::get(makeModuleStatsArrayTy(), Inits)})); 89 ModuleStatsGV->replaceAllUsesWith( 90 ConstantExpr::getBitCast(NewModuleStatsGV, ModuleStatsGV->getType())); 91 ModuleStatsGV->eraseFromParent(); 92 93 // Create a global constructor to register NewModuleStatsGV. 94 auto F = Function::Create(FunctionType::get(VoidTy, false), 95 GlobalValue::InternalLinkage, "", M); 96 auto BB = BasicBlock::Create(M->getContext(), "", F); 97 IRBuilder<> B(BB); 98 99 FunctionType *StatInitTy = FunctionType::get(VoidTy, Int8PtrTy, false); 100 FunctionCallee StatInit = 101 M->getOrInsertFunction("__sanitizer_stat_init", StatInitTy); 102 103 B.CreateCall(StatInit, ConstantExpr::getBitCast(NewModuleStatsGV, Int8PtrTy)); 104 B.CreateRetVoid(); 105 106 appendToGlobalCtors(*M, F, 0); 107 } 108