| //===--- SanitizerMetadata.cpp - Ignored entities for sanitizers ----------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // Class which emits metadata consumed by sanitizer instrumentation passes. |
| // |
| //===----------------------------------------------------------------------===// |
| #include "SanitizerMetadata.h" |
| #include "CodeGenModule.h" |
| #include "clang/AST/Attr.h" |
| #include "clang/AST/Type.h" |
| #include "clang/Basic/SourceManager.h" |
| #include "llvm/ADT/StringRef.h" |
| #include "llvm/IR/Constants.h" |
| |
| using namespace clang; |
| using namespace CodeGen; |
| |
| SanitizerMetadata::SanitizerMetadata(CodeGenModule &CGM) : CGM(CGM) {} |
| |
| static bool isAsanHwasanOrMemTag(const SanitizerSet& SS) { |
| return SS.hasOneOf(SanitizerKind::Address | SanitizerKind::KernelAddress | |
| SanitizerKind::HWAddress | SanitizerKind::KernelHWAddress | |
| SanitizerKind::MemTag); |
| } |
| |
| void SanitizerMetadata::reportGlobalToASan(llvm::GlobalVariable *GV, |
| SourceLocation Loc, StringRef Name, |
| QualType Ty, bool IsDynInit, |
| bool IsExcluded) { |
| if (!isAsanHwasanOrMemTag(CGM.getLangOpts().Sanitize)) |
| return; |
| IsDynInit &= !CGM.isInNoSanitizeList(GV, Loc, Ty, "init"); |
| IsExcluded |= CGM.isInNoSanitizeList(GV, Loc, Ty); |
| |
| llvm::Metadata *LocDescr = nullptr; |
| llvm::Metadata *GlobalName = nullptr; |
| llvm::LLVMContext &VMContext = CGM.getLLVMContext(); |
| if (!IsExcluded) { |
| // Don't generate source location and global name if it is on |
| // the NoSanitizeList - it won't be instrumented anyway. |
| LocDescr = getLocationMetadata(Loc); |
| if (!Name.empty()) |
| GlobalName = llvm::MDString::get(VMContext, Name); |
| } |
| |
| llvm::Metadata *GlobalMetadata[] = { |
| llvm::ConstantAsMetadata::get(GV), LocDescr, GlobalName, |
| llvm::ConstantAsMetadata::get( |
| llvm::ConstantInt::get(llvm::Type::getInt1Ty(VMContext), IsDynInit)), |
| llvm::ConstantAsMetadata::get(llvm::ConstantInt::get( |
| llvm::Type::getInt1Ty(VMContext), IsExcluded))}; |
| |
| llvm::MDNode *ThisGlobal = llvm::MDNode::get(VMContext, GlobalMetadata); |
| llvm::NamedMDNode *AsanGlobals = |
| CGM.getModule().getOrInsertNamedMetadata("llvm.asan.globals"); |
| AsanGlobals->addOperand(ThisGlobal); |
| } |
| |
| void SanitizerMetadata::reportGlobalToASan(llvm::GlobalVariable *GV, |
| const VarDecl &D, bool IsDynInit) { |
| if (!isAsanHwasanOrMemTag(CGM.getLangOpts().Sanitize)) |
| return; |
| std::string QualName; |
| llvm::raw_string_ostream OS(QualName); |
| D.printQualifiedName(OS); |
| |
| bool IsExcluded = false; |
| for (auto Attr : D.specific_attrs<NoSanitizeAttr>()) |
| if (Attr->getMask() & SanitizerKind::Address) |
| IsExcluded = true; |
| reportGlobalToASan(GV, D.getLocation(), OS.str(), D.getType(), IsDynInit, |
| IsExcluded); |
| } |
| |
| void SanitizerMetadata::disableSanitizerForGlobal(llvm::GlobalVariable *GV) { |
| // For now, just make sure the global is not modified by the ASan |
| // instrumentation. |
| if (isAsanHwasanOrMemTag(CGM.getLangOpts().Sanitize)) |
| reportGlobalToASan(GV, SourceLocation(), "", QualType(), false, true); |
| } |
| |
| void SanitizerMetadata::disableSanitizerForInstruction(llvm::Instruction *I) { |
| I->setMetadata(CGM.getModule().getMDKindID("nosanitize"), |
| llvm::MDNode::get(CGM.getLLVMContext(), None)); |
| } |
| |
| llvm::MDNode *SanitizerMetadata::getLocationMetadata(SourceLocation Loc) { |
| PresumedLoc PLoc = CGM.getContext().getSourceManager().getPresumedLoc(Loc); |
| if (!PLoc.isValid()) |
| return nullptr; |
| llvm::LLVMContext &VMContext = CGM.getLLVMContext(); |
| llvm::Metadata *LocMetadata[] = { |
| llvm::MDString::get(VMContext, PLoc.getFilename()), |
| llvm::ConstantAsMetadata::get(llvm::ConstantInt::get( |
| llvm::Type::getInt32Ty(VMContext), PLoc.getLine())), |
| llvm::ConstantAsMetadata::get(llvm::ConstantInt::get( |
| llvm::Type::getInt32Ty(VMContext), PLoc.getColumn())), |
| }; |
| return llvm::MDNode::get(VMContext, LocMetadata); |
| } |