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//===- SanitizerBinaryMetadata.cpp
//----------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file is a part of SanitizerBinaryMetadata.
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Instrumentation/SanitizerBinaryMetadata.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/InitializePasses.h"
#include "llvm/Pass.h"
#include <algorithm>
using namespace llvm;
namespace {
class MachineSanitizerBinaryMetadata : public MachineFunctionPass {
public:
static char ID;
MachineSanitizerBinaryMetadata();
bool runOnMachineFunction(MachineFunction &F) override;
};
} // namespace
INITIALIZE_PASS(MachineSanitizerBinaryMetadata, "machine-sanmd",
"Machine Sanitizer Binary Metadata", false, false)
char MachineSanitizerBinaryMetadata::ID = 0;
char &llvm::MachineSanitizerBinaryMetadataID =
MachineSanitizerBinaryMetadata::ID;
MachineSanitizerBinaryMetadata::MachineSanitizerBinaryMetadata()
: MachineFunctionPass(ID) {
initializeMachineSanitizerBinaryMetadataPass(
*PassRegistry::getPassRegistry());
}
bool MachineSanitizerBinaryMetadata::runOnMachineFunction(MachineFunction &MF) {
MDNode *MD = MF.getFunction().getMetadata(LLVMContext::MD_pcsections);
if (!MD)
return false;
const auto &Section = *cast<MDString>(MD->getOperand(0));
if (!Section.getString().equals(kSanitizerBinaryMetadataCoveredSection))
return false;
auto &AuxMDs = *cast<MDTuple>(MD->getOperand(1));
// Assume it currently only has features.
assert(AuxMDs.getNumOperands() == 1);
auto *Features = cast<ConstantAsMetadata>(AuxMDs.getOperand(0))->getValue();
if (!Features->getUniqueInteger()[kSanitizerBinaryMetadataUARBit])
return false;
// Calculate size of stack args for the function.
int64_t Size = 0;
uint64_t Align = 0;
const MachineFrameInfo &MFI = MF.getFrameInfo();
for (int i = -1; i >= (int)-MFI.getNumFixedObjects(); --i) {
Size = std::max(Size, MFI.getObjectOffset(i) + MFI.getObjectSize(i));
Align = std::max(Align, MFI.getObjectAlign(i).value());
}
Size = (Size + Align - 1) & ~(Align - 1);
auto &F = MF.getFunction();
IRBuilder<> IRB(F.getContext());
MDBuilder MDB(F.getContext());
// Keep the features and append size of stack args to the metadata.
F.setMetadata(LLVMContext::MD_pcsections,
MDB.createPCSections(
{{Section.getString(), {Features, IRB.getInt32(Size)}}}));
return false;
}
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