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