//===--- 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;

  if (D.hasAttr<DisableSanitizerInstrumentationAttr>())

    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);

}