SanitizerMetadata.cpp source code [clang_source_code/lib/CodeGen/SanitizerMetadata.cpp]

1	//===--- SanitizerMetadata.cpp - Blacklist 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/Type.h"
15	#include "llvm/ADT/StringRef.h"
16	#include "llvm/IR/Constants.h"
17
18	using namespace clang;
19	using namespace CodeGen;
20
21	SanitizerMetadata::SanitizerMetadata(CodeGenModule &CGM) : CGM(CGM) {}
22
23	void SanitizerMetadata::reportGlobalToASan(llvm::GlobalVariable *GV,
24	SourceLocation Loc, StringRef Name,
25	QualType Ty, bool IsDynInit,
26	bool IsBlacklisted) {
27	if (!CGM.getLangOpts().Sanitize.hasOneOf(SanitizerKind::Address \|
28	SanitizerKind::KernelAddress \|
29	SanitizerKind::HWAddress \|
30	SanitizerKind::KernelHWAddress))
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	SanitizerKind::KernelHWAddress))
65	return;
66	std::string QualName;
67	llvm::raw_string_ostream OS(QualName);
68	D.printQualifiedName(OS);
69
70	bool IsBlacklisted = false;
71	for (auto Attr : D.specific_attrs<NoSanitizeAttr>())
72	if (Attr->getMask() & SanitizerKind::Address)
73	IsBlacklisted = true;
74	reportGlobalToASan(GV, D.getLocation(), OS.str(), D.getType(), IsDynInit,
75	IsBlacklisted);
76	}
77
78	void SanitizerMetadata::disableSanitizerForGlobal(llvm::GlobalVariable *GV) {
79	// For now, just make sure the global is not modified by the ASan
80	// instrumentation.
81	if (CGM.getLangOpts().Sanitize.hasOneOf(SanitizerKind::Address \|
82	SanitizerKind::KernelAddress \|
83	SanitizerKind::HWAddress \|
84	SanitizerKind::KernelHWAddress))
85	reportGlobalToASan(GV, SourceLocation(), "", QualType(), false, true);
86	}
87
88	void SanitizerMetadata::disableSanitizerForInstruction(llvm::Instruction *I) {
89	I->setMetadata(CGM.getModule().getMDKindID("nosanitize"),
90	llvm::MDNode::get(CGM.getLLVMContext(), None));
91	}
92
93	llvm::MDNode *SanitizerMetadata::getLocationMetadata(SourceLocation Loc) {
94	PresumedLoc PLoc = CGM.getContext().getSourceManager().getPresumedLoc(Loc);
95	if (!PLoc.isValid())
96	return nullptr;
97	llvm::LLVMContext &VMContext = CGM.getLLVMContext();
98	llvm::Metadata *LocMetadata[] = {
99	llvm::MDString::get(VMContext, PLoc.getFilename()),
100	llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
101	llvm::Type::getInt32Ty(VMContext), PLoc.getLine())),
102	llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
103	llvm::Type::getInt32Ty(VMContext), PLoc.getColumn())),
104	};
105	return llvm::MDNode::get(VMContext, LocMetadata);
106	}
107

clang::CodeGen::SanitizerMetadata::reportGlobalToASan

clang::CodeGen::SanitizerMetadata::disableSanitizerForGlobal

clang::CodeGen::SanitizerMetadata::disableSanitizerForInstruction

clang::CodeGen::SanitizerMetadata::getLocationMetadata

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