1 //===--- SanitizerMetadata.cpp - Blacklist for sanitizers -----------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // Class which emits metadata consumed by sanitizer instrumentation passes. 11 // 12 //===----------------------------------------------------------------------===// 13 #include "SanitizerMetadata.h" 14 #include "CodeGenModule.h" 15 #include "clang/AST/Type.h" 16 #include "llvm/ADT/StringRef.h" 17 #include "llvm/IR/Constants.h" 18 19 using namespace clang; 20 using namespace CodeGen; 21 22 SanitizerMetadata::SanitizerMetadata(CodeGenModule &CGM) : CGM(CGM) {} 23 24 void SanitizerMetadata::reportGlobalToASan(llvm::GlobalVariable *GV, 25 SourceLocation Loc, StringRef Name, 26 QualType Ty, bool IsDynInit, 27 bool IsBlacklisted) { 28 if (!CGM.getLangOpts().Sanitize.hasOneOf(SanitizerKind::Address | 29 SanitizerKind::KernelAddress)) 30 return; 31 IsDynInit &= !CGM.isInSanitizerBlacklist(GV, Loc, Ty, "init"); 32 IsBlacklisted |= CGM.isInSanitizerBlacklist(GV, Loc, Ty); 33 34 llvm::Metadata *LocDescr = nullptr; 35 llvm::Metadata *GlobalName = nullptr; 36 llvm::LLVMContext &VMContext = CGM.getLLVMContext(); 37 if (!IsBlacklisted) { 38 // Don't generate source location and global name if it is blacklisted - 39 // it won't be instrumented anyway. 40 LocDescr = getLocationMetadata(Loc); 41 if (!Name.empty()) 42 GlobalName = llvm::MDString::get(VMContext, Name); 43 } 44 45 llvm::Metadata *GlobalMetadata[] = { 46 llvm::ConstantAsMetadata::get(GV), LocDescr, GlobalName, 47 llvm::ConstantAsMetadata::get( 48 llvm::ConstantInt::get(llvm::Type::getInt1Ty(VMContext), IsDynInit)), 49 llvm::ConstantAsMetadata::get(llvm::ConstantInt::get( 50 llvm::Type::getInt1Ty(VMContext), IsBlacklisted))}; 51 52 llvm::MDNode *ThisGlobal = llvm::MDNode::get(VMContext, GlobalMetadata); 53 llvm::NamedMDNode *AsanGlobals = 54 CGM.getModule().getOrInsertNamedMetadata("llvm.asan.globals"); 55 AsanGlobals->addOperand(ThisGlobal); 56 } 57 58 void SanitizerMetadata::reportGlobalToASan(llvm::GlobalVariable *GV, 59 const VarDecl &D, bool IsDynInit) { 60 if (!CGM.getLangOpts().Sanitize.hasOneOf(SanitizerKind::Address | 61 SanitizerKind::KernelAddress)) 62 return; 63 std::string QualName; 64 llvm::raw_string_ostream OS(QualName); 65 D.printQualifiedName(OS); 66 reportGlobalToASan(GV, D.getLocation(), OS.str(), D.getType(), IsDynInit); 67 } 68 69 void SanitizerMetadata::disableSanitizerForGlobal(llvm::GlobalVariable *GV) { 70 // For now, just make sure the global is not modified by the ASan 71 // instrumentation. 72 if (CGM.getLangOpts().Sanitize.hasOneOf(SanitizerKind::Address | 73 SanitizerKind::KernelAddress)) 74 reportGlobalToASan(GV, SourceLocation(), "", QualType(), false, true); 75 } 76 77 void SanitizerMetadata::disableSanitizerForInstruction(llvm::Instruction *I) { 78 I->setMetadata(CGM.getModule().getMDKindID("nosanitize"), 79 llvm::MDNode::get(CGM.getLLVMContext(), None)); 80 } 81 82 llvm::MDNode *SanitizerMetadata::getLocationMetadata(SourceLocation Loc) { 83 PresumedLoc PLoc = CGM.getContext().getSourceManager().getPresumedLoc(Loc); 84 if (!PLoc.isValid()) 85 return nullptr; 86 llvm::LLVMContext &VMContext = CGM.getLLVMContext(); 87 llvm::Metadata *LocMetadata[] = { 88 llvm::MDString::get(VMContext, PLoc.getFilename()), 89 llvm::ConstantAsMetadata::get(llvm::ConstantInt::get( 90 llvm::Type::getInt32Ty(VMContext), PLoc.getLine())), 91 llvm::ConstantAsMetadata::get(llvm::ConstantInt::get( 92 llvm::Type::getInt32Ty(VMContext), PLoc.getColumn())), 93 }; 94 return llvm::MDNode::get(VMContext, LocMetadata); 95 } 96
