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#pragma once
#ifdef __GNUC__
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-parameter"
#endif
//===- StackProtector.h - Stack Protector Insertion -------------*- C++ -*-===//
//
// 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 pass inserts stack protectors into functions which need them. A variable
// with a random value in it is stored onto the stack before the local variables
// are allocated. Upon exiting the block, the stored value is checked. If it's
// changed, then there was some sort of violation and the program aborts.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_STACKPROTECTOR_H
#define LLVM_CODEGEN_STACKPROTECTOR_H
#include "llvm/Analysis/DomTreeUpdater.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/PassManager.h"
#include "llvm/Pass.h"
#include "llvm/TargetParser/Triple.h"
namespace llvm {
class BasicBlock;
class Function;
class Module;
class TargetLoweringBase;
class TargetMachine;
class SSPLayoutInfo {
friend class StackProtectorPass;
friend class SSPLayoutAnalysis;
friend class StackProtector;
static constexpr unsigned DefaultSSPBufferSize = 8;
/// A mapping of AllocaInsts to their required SSP layout.
using SSPLayoutMap =
DenseMap<const AllocaInst *, MachineFrameInfo::SSPLayoutKind>;
/// Layout - Mapping of allocations to the required SSPLayoutKind.
/// StackProtector analysis will update this map when determining if an
/// AllocaInst triggers a stack protector.
SSPLayoutMap Layout;
/// The minimum size of buffers that will receive stack smashing
/// protection when -fstack-protection is used.
unsigned SSPBufferSize = DefaultSSPBufferSize;
bool RequireStackProtector = false;
// A prologue is generated.
bool HasPrologue = false;
// IR checking code is generated.
bool HasIRCheck = false;
public:
// Return true if StackProtector is supposed to be handled by SelectionDAG.
bool shouldEmitSDCheck(const BasicBlock &BB) const;
void copyToMachineFrameInfo(MachineFrameInfo &MFI) const;
};
class SSPLayoutAnalysis : public AnalysisInfoMixin<SSPLayoutAnalysis> {
friend AnalysisInfoMixin<SSPLayoutAnalysis>;
using SSPLayoutMap = SSPLayoutInfo::SSPLayoutMap;
static AnalysisKey Key;
public:
using Result = SSPLayoutInfo;
Result run(Function &F, FunctionAnalysisManager &FAM);
/// Check whether or not \p F needs a stack protector based upon the stack
/// protector level.
static bool requiresStackProtector(Function *F,
SSPLayoutMap *Layout = nullptr);
};
class StackProtectorPass : public PassInfoMixin<StackProtectorPass> {
const TargetMachine *TM;
public:
explicit StackProtectorPass(const TargetMachine *TM) : TM(TM) {}
PreservedAnalyses run(Function &F, FunctionAnalysisManager &FAM);
};
class StackProtector : public FunctionPass {
private:
/// A mapping of AllocaInsts to their required SSP layout.
using SSPLayoutMap = SSPLayoutInfo::SSPLayoutMap;
const TargetMachine *TM = nullptr;
Function *F = nullptr;
Module *M = nullptr;
std::optional<DomTreeUpdater> DTU;
SSPLayoutInfo LayoutInfo;
public:
static char ID; // Pass identification, replacement for typeid.
StackProtector();
void getAnalysisUsage(AnalysisUsage &AU) const override;
// Return true if StackProtector is supposed to be handled by SelectionDAG.
bool shouldEmitSDCheck(const BasicBlock &BB) const {
return LayoutInfo.shouldEmitSDCheck(BB);
}
bool runOnFunction(Function &Fn) override;
void copyToMachineFrameInfo(MachineFrameInfo &MFI) const {
LayoutInfo.copyToMachineFrameInfo(MFI);
}
/// Check whether or not \p F needs a stack protector based upon the stack
/// protector level.
static bool requiresStackProtector(Function *F,
SSPLayoutMap *Layout = nullptr) {
return SSPLayoutAnalysis::requiresStackProtector(F, Layout);
}
};
} // end namespace llvm
#endif // LLVM_CODEGEN_STACKPROTECTOR_H
#ifdef __GNUC__
#pragma GCC diagnostic pop
#endif
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