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
19using namespace clang;
20using namespace CodeGen;
21
22SanitizerMetadata::SanitizerMetadata(CodeGenModule &CGM) : CGM(CGM) {}
23
24void 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    return;
31  IsDynInit &= !CGM.isInSanitizerBlacklist(GV, Loc, Ty, "init");
32  IsBlacklisted |= CGM.isInSanitizerBlacklist(GV, Loc, Ty);
33
34  llvm::Metadata *LocDescr = nullptr;
35  llvm::Metadata *GlobalName = nullptr;
36  llvm::LLVMContext &VMContext = CGM.getLLVMContext();
37  if (!IsBlacklisted) {
38    // Don't generate source location and global name if it is blacklisted -
39    // it won't be instrumented anyway.
40    LocDescr = getLocationMetadata(Loc);
41    if (!Name.empty())
42      GlobalName = llvm::MDString::get(VMContext, Name);
43  }
44
45  llvm::Metadata *GlobalMetadata[] = {
46      llvm::ConstantAsMetadata::get(GV), LocDescr, GlobalName,
47      llvm::ConstantAsMetadata::get(
48          llvm::ConstantInt::get(llvm::Type::getInt1Ty(VMContext), IsDynInit)),
49      llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
50          llvm::Type::getInt1Ty(VMContext), IsBlacklisted))};
51
52  llvm::MDNode *ThisGlobal = llvm::MDNode::get(VMContext, GlobalMetadata);
53  llvm::NamedMDNode *AsanGlobals =
54      CGM.getModule().getOrInsertNamedMetadata("llvm.asan.globals");
55  AsanGlobals->addOperand(ThisGlobal);
56}
57
58void SanitizerMetadata::reportGlobalToASan(llvm::GlobalVariable *GV,
59                                           const VarDecl &D, bool IsDynInit) {
60  if (!CGM.getLangOpts().Sanitize.hasOneOf(SanitizerKind::Address |
61                                           SanitizerKind::KernelAddress))
62    return;
63  std::string QualName;
64  llvm::raw_string_ostream OS(QualName);
65  D.printQualifiedName(OS);
66  reportGlobalToASan(GV, D.getLocation(), OS.str(), D.getType(), IsDynInit);
67}
68
69void SanitizerMetadata::disableSanitizerForGlobal(llvm::GlobalVariable *GV) {
70  // For now, just make sure the global is not modified by the ASan
71  // instrumentation.
72  if (CGM.getLangOpts().Sanitize.hasOneOf(SanitizerKind::Address |
73                                          SanitizerKind::KernelAddress))
74    reportGlobalToASan(GV, SourceLocation(), "", QualType(), false, true);
75}
76
77void SanitizerMetadata::disableSanitizerForInstruction(llvm::Instruction *I) {
78  I->setMetadata(CGM.getModule().getMDKindID("nosanitize"),
79                 llvm::MDNode::get(CGM.getLLVMContext(), None));
80}
81
82llvm::MDNode *SanitizerMetadata::getLocationMetadata(SourceLocation Loc) {
83  PresumedLoc PLoc = CGM.getContext().getSourceManager().getPresumedLoc(Loc);
84  if (!PLoc.isValid())
85    return nullptr;
86  llvm::LLVMContext &VMContext = CGM.getLLVMContext();
87  llvm::Metadata *LocMetadata[] = {
88      llvm::MDString::get(VMContext, PLoc.getFilename()),
89      llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
90          llvm::Type::getInt32Ty(VMContext), PLoc.getLine())),
91      llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
92          llvm::Type::getInt32Ty(VMContext), PLoc.getColumn())),
93  };
94  return llvm::MDNode::get(VMContext, LocMetadata);
95}
96