d9ad5cec0c
Instead of creating global variables for source locations and global names, just create metadata nodes and strings. They will be transformed into actual globals in the instrumentation pass (if necessary). This approach is more flexible: 1) we don't have to ensure that our custom globals survive all the optimizations 2) if globals are discarded for some reason, we will simply ignore metadata for them and won't have to erase corresponding globals 3) metadata for source locations can be reused for other purposes: e.g. we may attach source location metadata to alloca instructions and provide better descriptions for stack variables in ASan error reports. No functionality change. llvm-svn: 214604
83 lines
3.1 KiB
C++
83 lines
3.1 KiB
C++
//===--- SanitizerMetadata.cpp - Blacklist for sanitizers -----------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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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 "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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void SanitizerMetadata::reportGlobalToASan(llvm::GlobalVariable *GV,
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SourceLocation Loc, StringRef Name,
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bool IsDynInit, bool IsBlacklisted) {
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if (!CGM.getLangOpts().Sanitize.Address)
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return;
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IsDynInit &= !CGM.getSanitizerBlacklist().isIn(*GV, "init");
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IsBlacklisted |= CGM.getSanitizerBlacklist().isIn(*GV);
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llvm::Value *LocDescr = nullptr;
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llvm::Value *GlobalName = nullptr;
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llvm::LLVMContext &VMContext = CGM.getLLVMContext();
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if (!IsBlacklisted) {
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// Don't generate source location and global name if it is blacklisted -
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// it won't be instrumented anyway.
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LocDescr = getLocationMetadata(Loc);
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if (!Name.empty())
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GlobalName = llvm::MDString::get(VMContext, Name);
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}
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llvm::Value *GlobalMetadata[] = {
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GV, LocDescr, GlobalName,
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llvm::ConstantInt::get(llvm::Type::getInt1Ty(VMContext), IsDynInit),
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llvm::ConstantInt::get(llvm::Type::getInt1Ty(VMContext), IsBlacklisted)};
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llvm::MDNode *ThisGlobal = llvm::MDNode::get(VMContext, GlobalMetadata);
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llvm::NamedMDNode *AsanGlobals =
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CGM.getModule().getOrInsertNamedMetadata("llvm.asan.globals");
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AsanGlobals->addOperand(ThisGlobal);
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}
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void SanitizerMetadata::reportGlobalToASan(llvm::GlobalVariable *GV,
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const VarDecl &D, bool IsDynInit) {
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if (!CGM.getLangOpts().Sanitize.Address)
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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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reportGlobalToASan(GV, D.getLocation(), OS.str(), IsDynInit);
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}
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void SanitizerMetadata::disableSanitizerForGlobal(llvm::GlobalVariable *GV) {
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// For now, just make sure the global is not modified by the ASan
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// instrumentation.
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if (CGM.getLangOpts().Sanitize.Address)
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reportGlobalToASan(GV, SourceLocation(), "", false, true);
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}
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llvm::MDNode *SanitizerMetadata::getLocationMetadata(SourceLocation Loc) {
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PresumedLoc PLoc = CGM.getContext().getSourceManager().getPresumedLoc(Loc);
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if (!PLoc.isValid())
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return nullptr;
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llvm::LLVMContext &VMContext = CGM.getLLVMContext();
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llvm::Value *LocMetadata[] = {
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llvm::MDString::get(VMContext, PLoc.getFilename()),
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llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), PLoc.getLine()),
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llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext),
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PLoc.getColumn()),
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};
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return llvm::MDNode::get(VMContext, LocMetadata);
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}
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