110 lines · cpp
1//===- SanitizerBinaryMetadata.cpp2//----------------------------------------------===//3//4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.5// See https://llvm.org/LICENSE.txt for license information.6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception7//8//===----------------------------------------------------------------------===//9//10// This file is a part of SanitizerBinaryMetadata.11//12//===----------------------------------------------------------------------===//13 14#include "llvm/CodeGen/SanitizerBinaryMetadata.h"15#include "llvm/CodeGen/MachineFrameInfo.h"16#include "llvm/CodeGen/MachineFunction.h"17#include "llvm/CodeGen/MachineFunctionPass.h"18#include "llvm/CodeGen/Passes.h"19#include "llvm/IR/IRBuilder.h"20#include "llvm/IR/MDBuilder.h"21#include "llvm/InitializePasses.h"22#include "llvm/Pass.h"23#include "llvm/Transforms/Instrumentation/SanitizerBinaryMetadata.h"24#include <algorithm>25 26using namespace llvm;27 28namespace {29// FIXME: This pass modifies Function metadata, which is not to be done in30// MachineFunctionPass. It should probably be moved to a FunctionPass.31class MachineSanitizerBinaryMetadataLegacy : public MachineFunctionPass {32public:33 static char ID;34 35 MachineSanitizerBinaryMetadataLegacy();36 bool runOnMachineFunction(MachineFunction &F) override;37};38 39struct MachineSanitizerBinaryMetadata {40 bool run(MachineFunction &MF);41};42 43} // namespace44 45INITIALIZE_PASS(MachineSanitizerBinaryMetadataLegacy, "machine-sanmd",46 "Machine Sanitizer Binary Metadata", false, false)47 48char MachineSanitizerBinaryMetadataLegacy::ID = 0;49char &llvm::MachineSanitizerBinaryMetadataID =50 MachineSanitizerBinaryMetadataLegacy::ID;51 52MachineSanitizerBinaryMetadataLegacy::MachineSanitizerBinaryMetadataLegacy()53 : MachineFunctionPass(ID) {54 initializeMachineSanitizerBinaryMetadataLegacyPass(55 *PassRegistry::getPassRegistry());56}57 58bool MachineSanitizerBinaryMetadataLegacy::runOnMachineFunction(59 MachineFunction &MF) {60 return MachineSanitizerBinaryMetadata().run(MF);61}62 63PreservedAnalyses64MachineSanitizerBinaryMetadataPass::run(MachineFunction &MF,65 MachineFunctionAnalysisManager &MFAM) {66 if (!MachineSanitizerBinaryMetadata().run(MF))67 return PreservedAnalyses::all();68 69 return getMachineFunctionPassPreservedAnalyses();70}71 72bool MachineSanitizerBinaryMetadata::run(MachineFunction &MF) {73 MDNode *MD = MF.getFunction().getMetadata(LLVMContext::MD_pcsections);74 if (!MD)75 return false;76 const auto &Section = *cast<MDString>(MD->getOperand(0));77 if (!Section.getString().starts_with(kSanitizerBinaryMetadataCoveredSection))78 return false;79 auto &AuxMDs = *cast<MDTuple>(MD->getOperand(1));80 // Assume it currently only has features.81 assert(AuxMDs.getNumOperands() == 1);82 Constant *Features =83 cast<ConstantAsMetadata>(AuxMDs.getOperand(0))->getValue();84 if (!Features->getUniqueInteger()[kSanitizerBinaryMetadataUARBit])85 return false;86 // Calculate size of stack args for the function.87 int64_t Size = 0;88 uint64_t Align = 0;89 const MachineFrameInfo &MFI = MF.getFrameInfo();90 for (int i = -1; i >= (int)-MFI.getNumFixedObjects(); --i) {91 Size = std::max(Size, MFI.getObjectOffset(i) + MFI.getObjectSize(i));92 Align = std::max(Align, MFI.getObjectAlign(i).value());93 }94 Size = (Size + Align - 1) & ~(Align - 1);95 if (!Size)96 return false;97 // Non-zero size, update metadata.98 auto &F = MF.getFunction();99 IRBuilder<> IRB(F.getContext());100 MDBuilder MDB(F.getContext());101 // Keep the features and append size of stack args to the metadata.102 APInt NewFeatures = Features->getUniqueInteger();103 NewFeatures.setBit(kSanitizerBinaryMetadataUARHasSizeBit);104 F.setMetadata(105 LLVMContext::MD_pcsections,106 MDB.createPCSections({{Section.getString(),107 {IRB.getInt(NewFeatures), IRB.getInt32(Size)}}}));108 return false;109}110