90e5a8ac47
For MTE globals, we should have clang emit the attribute for all GV's that it creates, and then use that in the upcoming AArch64 global tagging IR pass. We need a positive attribute for this sanitizer (rather than implicit sanitization of all globals) because it needs to interact with other parts of LLVM, including: 1. Suppressing certain global optimisations (like merging), 2. Emitting extra directives by the ASM writer, and 3. Putting extra information in the symbol table entries. While this does technically make the LLVM IR / bitcode format non-backwards-compatible, nobody should have used this attribute yet, because it's a no-op. Reviewed By: eugenis Differential Revision: https://reviews.llvm.org/D128950
109 lines
4.2 KiB
C++
109 lines
4.2 KiB
C++
//===--- SanitizerMetadata.cpp - Ignored entities for sanitizers ----------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// Class which emits metadata consumed by sanitizer instrumentation passes.
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//
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//===----------------------------------------------------------------------===//
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#include "SanitizerMetadata.h"
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#include "CodeGenModule.h"
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#include "clang/AST/Attr.h"
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#include "clang/AST/Type.h"
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#include "clang/Basic/SourceManager.h"
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#include "llvm/ADT/StringRef.h"
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#include "llvm/IR/Constants.h"
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using namespace clang;
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using namespace CodeGen;
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SanitizerMetadata::SanitizerMetadata(CodeGenModule &CGM) : CGM(CGM) {}
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static bool isAsanHwasanOrMemTag(const SanitizerSet &SS) {
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return SS.hasOneOf(SanitizerKind::Address | SanitizerKind::KernelAddress |
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SanitizerKind::HWAddress | SanitizerKind::MemTag);
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}
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SanitizerMask expandKernelSanitizerMasks(SanitizerMask Mask) {
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if (Mask & (SanitizerKind::Address | SanitizerKind::KernelAddress))
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Mask |= SanitizerKind::Address | SanitizerKind::KernelAddress;
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// Note: KHWASan doesn't support globals.
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return Mask;
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}
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void SanitizerMetadata::reportGlobal(llvm::GlobalVariable *GV,
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SourceLocation Loc, StringRef Name,
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QualType Ty,
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SanitizerMask NoSanitizeAttrMask,
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bool IsDynInit) {
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SanitizerSet FsanitizeArgument = CGM.getLangOpts().Sanitize;
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if (!isAsanHwasanOrMemTag(FsanitizeArgument))
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return;
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FsanitizeArgument.Mask = expandKernelSanitizerMasks(FsanitizeArgument.Mask);
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NoSanitizeAttrMask = expandKernelSanitizerMasks(NoSanitizeAttrMask);
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SanitizerSet NoSanitizeAttrSet = {NoSanitizeAttrMask &
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FsanitizeArgument.Mask};
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llvm::GlobalVariable::SanitizerMetadata Meta;
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if (GV->hasSanitizerMetadata())
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Meta = GV->getSanitizerMetadata();
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Meta.NoAddress |= NoSanitizeAttrSet.hasOneOf(SanitizerKind::Address);
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Meta.NoAddress |= CGM.isInNoSanitizeList(
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FsanitizeArgument.Mask & SanitizerKind::Address, GV, Loc, Ty);
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Meta.NoHWAddress |= NoSanitizeAttrSet.hasOneOf(SanitizerKind::HWAddress);
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Meta.NoHWAddress |= CGM.isInNoSanitizeList(
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FsanitizeArgument.Mask & SanitizerKind::HWAddress, GV, Loc, Ty);
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Meta.Memtag |=
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static_cast<bool>(FsanitizeArgument.Mask & SanitizerKind::MemtagGlobals);
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Meta.Memtag &= !NoSanitizeAttrSet.hasOneOf(SanitizerKind::MemTag);
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Meta.Memtag &= !CGM.isInNoSanitizeList(
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FsanitizeArgument.Mask & SanitizerKind::MemTag, GV, Loc, Ty);
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Meta.IsDynInit = IsDynInit && !Meta.NoAddress &&
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FsanitizeArgument.has(SanitizerKind::Address) &&
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!CGM.isInNoSanitizeList(SanitizerKind::Address |
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SanitizerKind::KernelAddress,
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GV, Loc, Ty, "init");
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GV->setSanitizerMetadata(Meta);
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}
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void SanitizerMetadata::reportGlobal(llvm::GlobalVariable *GV, const VarDecl &D,
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bool IsDynInit) {
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if (!isAsanHwasanOrMemTag(CGM.getLangOpts().Sanitize))
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return;
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std::string QualName;
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llvm::raw_string_ostream OS(QualName);
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D.printQualifiedName(OS);
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auto getNoSanitizeMask = [](const VarDecl &D) {
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if (D.hasAttr<DisableSanitizerInstrumentationAttr>())
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return SanitizerKind::All;
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SanitizerMask NoSanitizeMask;
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for (auto *Attr : D.specific_attrs<NoSanitizeAttr>())
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NoSanitizeMask |= Attr->getMask();
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return NoSanitizeMask;
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};
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reportGlobal(GV, D.getLocation(), OS.str(), D.getType(), getNoSanitizeMask(D),
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IsDynInit);
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}
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void SanitizerMetadata::disableSanitizerForGlobal(llvm::GlobalVariable *GV) {
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reportGlobal(GV, SourceLocation(), "", QualType(), SanitizerKind::All);
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}
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void SanitizerMetadata::disableSanitizerForInstruction(llvm::Instruction *I) {
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I->setMetadata(llvm::LLVMContext::MD_nosanitize,
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llvm::MDNode::get(CGM.getLLVMContext(), None));
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}
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