contrib/llvm/tools/clang/lib/CodeGen/SanitizerMetadata.cpp

   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                                            SanitizerKind::HWAddress))
  31     return;
  32   IsDynInit &= !CGM.isInSanitizerBlacklist(GV, Loc, Ty, "init");
  33   IsBlacklisted |= CGM.isInSanitizerBlacklist(GV, Loc, Ty);
  34
  35   llvm::Metadata *LocDescr = nullptr;
  36   llvm::Metadata *GlobalName = nullptr;
  37   llvm::LLVMContext &VMContext = CGM.getLLVMContext();
  38   if (!IsBlacklisted) {
  39     // Don't generate source location and global name if it is blacklisted -
  40     // it won't be instrumented anyway.
  41     LocDescr = getLocationMetadata(Loc);
  42     if (!Name.empty())
  43       GlobalName = llvm::MDString::get(VMContext, Name);
  44   }
  45
  46   llvm::Metadata *GlobalMetadata[] = {
  47       llvm::ConstantAsMetadata::get(GV), LocDescr, GlobalName,
  48       llvm::ConstantAsMetadata::get(
  49           llvm::ConstantInt::get(llvm::Type::getInt1Ty(VMContext), IsDynInit)),
  50       llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
  51           llvm::Type::getInt1Ty(VMContext), IsBlacklisted))};
  52
  53   llvm::MDNode *ThisGlobal = llvm::MDNode::get(VMContext, GlobalMetadata);
  54   llvm::NamedMDNode *AsanGlobals =
  55       CGM.getModule().getOrInsertNamedMetadata("llvm.asan.globals");
  56   AsanGlobals->addOperand(ThisGlobal);
  57 }
  58
  59 void SanitizerMetadata::reportGlobalToASan(llvm::GlobalVariable *GV,
  60                                            const VarDecl &D, bool IsDynInit) {
  61   if (!CGM.getLangOpts().Sanitize.hasOneOf(SanitizerKind::Address |
  62                                            SanitizerKind::KernelAddress |
  63                                            SanitizerKind::HWAddress))
  64     return;
  65   std::string QualName;
  66   llvm::raw_string_ostream OS(QualName);
  67   D.printQualifiedName(OS);
  68
  69   bool IsBlacklisted = false;
  70   for (auto Attr : D.specific_attrs<NoSanitizeAttr>())
  71     if (Attr->getMask() & SanitizerKind::Address)
  72       IsBlacklisted = true;
  73   reportGlobalToASan(GV, D.getLocation(), OS.str(), D.getType(), IsDynInit,
  74                      IsBlacklisted);
  75 }
  76
  77 void SanitizerMetadata::disableSanitizerForGlobal(llvm::GlobalVariable *GV) {
  78   // For now, just make sure the global is not modified by the ASan
  79   // instrumentation.
  80   if (CGM.getLangOpts().Sanitize.hasOneOf(SanitizerKind::Address |
  81                                           SanitizerKind::KernelAddress |
  82                                           SanitizerKind::HWAddress))
  83     reportGlobalToASan(GV, SourceLocation(), "", QualType(), false, true);
  84 }
  85
  86 void SanitizerMetadata::disableSanitizerForInstruction(llvm::Instruction *I) {
  87   I->setMetadata(CGM.getModule().getMDKindID("nosanitize"),
  88                  llvm::MDNode::get(CGM.getLLVMContext(), None));
  89 }
  90
  91 llvm::MDNode *SanitizerMetadata::getLocationMetadata(SourceLocation Loc) {
  92   PresumedLoc PLoc = CGM.getContext().getSourceManager().getPresumedLoc(Loc);
  93   if (!PLoc.isValid())
  94     return nullptr;
  95   llvm::LLVMContext &VMContext = CGM.getLLVMContext();
  96   llvm::Metadata *LocMetadata[] = {
  97       llvm::MDString::get(VMContext, PLoc.getFilename()),
  98       llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
  99           llvm::Type::getInt32Ty(VMContext), PLoc.getLine())),
 100       llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
 101           llvm::Type::getInt32Ty(VMContext), PLoc.getColumn())),
 102   };
 103   return llvm::MDNode::get(VMContext, LocMetadata);
 104 }