clang/lib/CodeGen/SanitizerMetadata.cpp

   1 //===--- SanitizerMetadata.cpp - Ignored entities for sanitizers ----------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // Class which emits metadata consumed by sanitizer instrumentation passes.
  10 //
  11 //===----------------------------------------------------------------------===//
  12 #include "SanitizerMetadata.h"
  13 #include "CodeGenModule.h"
  14 #include "clang/AST/Attr.h"
  15 #include "clang/AST/Type.h"
  16 #include "clang/Basic/SourceManager.h"
  17 #include "llvm/ADT/StringRef.h"
  18 #include "llvm/IR/Constants.h"
  19
  20 using namespace clang;
  21 using namespace CodeGen;
  22
  23 SanitizerMetadata::SanitizerMetadata(CodeGenModule &CGM) : CGM(CGM) {}
  24
  25 static bool isAsanHwasanOrMemTag(const SanitizerSet &SS) {
  26   return SS.hasOneOf(SanitizerKind::Address | SanitizerKind::KernelAddress |
  27                      SanitizerKind::HWAddress | SanitizerKind::MemTag);
  28 }
  29
  30 SanitizerMask expandKernelSanitizerMasks(SanitizerMask Mask) {
  31   if (Mask & (SanitizerKind::Address | SanitizerKind::KernelAddress))
  32     Mask |= SanitizerKind::Address | SanitizerKind::KernelAddress;
  33   // Note: KHWASan doesn't support globals.
  34   return Mask;
  35 }
  36
  37 void SanitizerMetadata::reportGlobal(llvm::GlobalVariable *GV,
  38                                      SourceLocation Loc, StringRef Name,
  39                                      QualType Ty,
  40                                      SanitizerMask NoSanitizeAttrMask,
  41                                      bool IsDynInit) {
  42   SanitizerSet FsanitizeArgument = CGM.getLangOpts().Sanitize;
  43   if (!isAsanHwasanOrMemTag(FsanitizeArgument))
  44     return;
  45
  46   FsanitizeArgument.Mask = expandKernelSanitizerMasks(FsanitizeArgument.Mask);
  47   NoSanitizeAttrMask = expandKernelSanitizerMasks(NoSanitizeAttrMask);
  48   SanitizerSet NoSanitizeAttrSet = {NoSanitizeAttrMask &
  49                                     FsanitizeArgument.Mask};
  50
  51   llvm::GlobalVariable::SanitizerMetadata Meta;
  52   if (GV->hasSanitizerMetadata())
  53     Meta = GV->getSanitizerMetadata();
  54
  55   Meta.NoAddress |= NoSanitizeAttrSet.hasOneOf(SanitizerKind::Address);
  56   Meta.NoAddress |= CGM.isInNoSanitizeList(
  57       FsanitizeArgument.Mask & SanitizerKind::Address, GV, Loc, Ty);
  58
  59   Meta.NoHWAddress |= NoSanitizeAttrSet.hasOneOf(SanitizerKind::HWAddress);
  60   Meta.NoHWAddress |= CGM.isInNoSanitizeList(
  61       FsanitizeArgument.Mask & SanitizerKind::HWAddress, GV, Loc, Ty);
  62
  63   Meta.Memtag |=
  64       static_cast<bool>(FsanitizeArgument.Mask & SanitizerKind::MemtagGlobals);
  65   Meta.Memtag &= !NoSanitizeAttrSet.hasOneOf(SanitizerKind::MemTag);
  66   Meta.Memtag &= !CGM.isInNoSanitizeList(
  67       FsanitizeArgument.Mask & SanitizerKind::MemTag, GV, Loc, Ty);
  68
  69   Meta.IsDynInit = IsDynInit && !Meta.NoAddress &&
  70                    FsanitizeArgument.has(SanitizerKind::Address) &&
  71                    !CGM.isInNoSanitizeList(SanitizerKind::Address |
  72                                                SanitizerKind::KernelAddress,
  73                                            GV, Loc, Ty, "init");
  74
  75   GV->setSanitizerMetadata(Meta);
  76 }
  77
  78 void SanitizerMetadata::reportGlobal(llvm::GlobalVariable *GV, const VarDecl &D,
  79                                      bool IsDynInit) {
  80   if (!isAsanHwasanOrMemTag(CGM.getLangOpts().Sanitize))
  81     return;
  82   std::string QualName;
  83   llvm::raw_string_ostream OS(QualName);
  84   D.printQualifiedName(OS);
  85
  86   auto getNoSanitizeMask = [](const VarDecl &D) {
  87     if (D.hasAttr<DisableSanitizerInstrumentationAttr>())
  88       return SanitizerKind::All;
  89
  90     SanitizerMask NoSanitizeMask;
  91     for (auto *Attr : D.specific_attrs<NoSanitizeAttr>())
  92       NoSanitizeMask |= Attr->getMask();
  93
  94     return NoSanitizeMask;
  95   };
  96
  97   reportGlobal(GV, D.getLocation(), OS.str(), D.getType(), getNoSanitizeMask(D),
  98                IsDynInit);
  99 }
 100
 101 void SanitizerMetadata::disableSanitizerForGlobal(llvm::GlobalVariable *GV) {
 102   reportGlobal(GV, SourceLocation(), "", QualType(), SanitizerKind::All);
 103 }