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.has(SanitizerKind::Address)) 29 return; 30 IsDynInit &= !CGM.isInSanitizerBlacklist(GV, Loc, Ty, "init"); 31 IsBlacklisted |= CGM.isInSanitizerBlacklist(GV, Loc, Ty); 32 33 llvm::Metadata *LocDescr = nullptr; 34 llvm::Metadata *GlobalName = nullptr; 35 llvm::LLVMContext &VMContext = CGM.getLLVMContext(); 36 if (!IsBlacklisted) { 37 // Don't generate source location and global name if it is blacklisted - 38 // it won't be instrumented anyway. 39 LocDescr = getLocationMetadata(Loc); 40 if (!Name.empty()) 41 GlobalName = llvm::MDString::get(VMContext, Name); 42 } 43 44 llvm::Metadata *GlobalMetadata[] = { 45 llvm::ConstantAsMetadata::get(GV), LocDescr, GlobalName, 46 llvm::ConstantAsMetadata::get( 47 llvm::ConstantInt::get(llvm::Type::getInt1Ty(VMContext), IsDynInit)), 48 llvm::ConstantAsMetadata::get(llvm::ConstantInt::get( 49 llvm::Type::getInt1Ty(VMContext), IsBlacklisted))}; 50 51 llvm::MDNode *ThisGlobal = llvm::MDNode::get(VMContext, GlobalMetadata); 52 llvm::NamedMDNode *AsanGlobals = 53 CGM.getModule().getOrInsertNamedMetadata("llvm.asan.globals"); 54 AsanGlobals->addOperand(ThisGlobal); 55 } 56 57 void SanitizerMetadata::reportGlobalToASan(llvm::GlobalVariable *GV, 58 const VarDecl &D, bool IsDynInit) { 59 if (!CGM.getLangOpts().Sanitize.has(SanitizerKind::Address)) 60 return; 61 std::string QualName; 62 llvm::raw_string_ostream OS(QualName); 63 D.printQualifiedName(OS); 64 reportGlobalToASan(GV, D.getLocation(), OS.str(), D.getType(), IsDynInit); 65 } 66 67 void SanitizerMetadata::disableSanitizerForGlobal(llvm::GlobalVariable *GV) { 68 // For now, just make sure the global is not modified by the ASan 69 // instrumentation. 70 if (CGM.getLangOpts().Sanitize.has(SanitizerKind::Address)) 71 reportGlobalToASan(GV, SourceLocation(), "", QualType(), false, true); 72 } 73 74 void SanitizerMetadata::disableSanitizerForInstruction(llvm::Instruction *I) { 75 I->setMetadata(CGM.getModule().getMDKindID("nosanitize"), 76 llvm::MDNode::get(CGM.getLLVMContext(), None)); 77 } 78 79 llvm::MDNode *SanitizerMetadata::getLocationMetadata(SourceLocation Loc) { 80 PresumedLoc PLoc = CGM.getContext().getSourceManager().getPresumedLoc(Loc); 81 if (!PLoc.isValid()) 82 return nullptr; 83 llvm::LLVMContext &VMContext = CGM.getLLVMContext(); 84 llvm::Metadata *LocMetadata[] = { 85 llvm::MDString::get(VMContext, PLoc.getFilename()), 86 llvm::ConstantAsMetadata::get(llvm::ConstantInt::get( 87 llvm::Type::getInt32Ty(VMContext), PLoc.getLine())), 88 llvm::ConstantAsMetadata::get(llvm::ConstantInt::get( 89 llvm::Type::getInt32Ty(VMContext), PLoc.getColumn())), 90 }; 91 return llvm::MDNode::get(VMContext, LocMetadata); 92 } 93