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//===- StackSafetyAnalysis.h - Stack memory safety analysis -----*- 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
//
//===----------------------------------------------------------------------===//
//
// Stack Safety Analysis detects allocas and arguments with safe access.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_STACKSAFETYANALYSIS_H
#define LLVM_ANALYSIS_STACKSAFETYANALYSIS_H
#include "llvm/IR/ModuleSummaryIndex.h"
#include "llvm/IR/PassManager.h"
#include "llvm/Pass.h"
namespace llvm {
class AllocaInst;
class ScalarEvolution;
/// Interface to access stack safety analysis results for single function.
class StackSafetyInfo {
public:
struct InfoTy;
private:
Function *F = nullptr;
std::function<ScalarEvolution &()> GetSE;
mutable std::unique_ptr<InfoTy> Info;
public:
StackSafetyInfo();
StackSafetyInfo(Function *F, std::function<ScalarEvolution &()> GetSE);
StackSafetyInfo(StackSafetyInfo &&);
StackSafetyInfo &operator=(StackSafetyInfo &&);
~StackSafetyInfo();
const InfoTy &getInfo() const;
// TODO: Add useful for client methods.
void print(raw_ostream &O) const;
/// Parameters use for a FunctionSummary.
/// Function collects access information of all pointer parameters.
/// Information includes a range of direct access of parameters by the
/// functions and all call sites accepting the parameter.
/// StackSafety assumes that missing parameter information means possibility
/// of access to the parameter with any offset, so we can correctly link
/// code without StackSafety information, e.g. non-ThinLTO.
std::vector<FunctionSummary::ParamAccess>
getParamAccesses(ModuleSummaryIndex &Index) const;
};
class StackSafetyGlobalInfo {
public:
struct InfoTy;
private:
Module *M = nullptr;
std::function<const StackSafetyInfo &(Function &F)> GetSSI;
const ModuleSummaryIndex *Index = nullptr;
mutable std::unique_ptr<InfoTy> Info;
const InfoTy &getInfo() const;
public:
StackSafetyGlobalInfo();
StackSafetyGlobalInfo(
Module *M, std::function<const StackSafetyInfo &(Function &F)> GetSSI,
const ModuleSummaryIndex *Index);
StackSafetyGlobalInfo(StackSafetyGlobalInfo &&);
StackSafetyGlobalInfo &operator=(StackSafetyGlobalInfo &&);
~StackSafetyGlobalInfo();
// Whether we can prove that all accesses to this Alloca are in-range and
// during its lifetime.
bool isSafe(const AllocaInst &AI) const;
// Returns true if the instruction can be proven to do only two types of
// memory accesses:
// (1) live stack locations in-bounds or
// (2) non-stack locations.
bool stackAccessIsSafe(const Instruction &I) const;
void print(raw_ostream &O) const;
void dump() const;
};
/// StackSafetyInfo wrapper for the new pass manager.
class StackSafetyAnalysis : public AnalysisInfoMixin<StackSafetyAnalysis> {
friend AnalysisInfoMixin<StackSafetyAnalysis>;
static AnalysisKey Key;
public:
using Result = StackSafetyInfo;
StackSafetyInfo run(Function &F, FunctionAnalysisManager &AM);
};
/// Printer pass for the \c StackSafetyAnalysis results.
class StackSafetyPrinterPass : public PassInfoMixin<StackSafetyPrinterPass> {
raw_ostream &OS;
public:
explicit StackSafetyPrinterPass(raw_ostream &OS) : OS(OS) {}
PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
};
/// StackSafetyInfo wrapper for the legacy pass manager
class StackSafetyInfoWrapperPass : public FunctionPass {
StackSafetyInfo SSI;
public:
static char ID;
StackSafetyInfoWrapperPass();
const StackSafetyInfo &getResult() const { return SSI; }
void print(raw_ostream &O, const Module *M) const override;
void getAnalysisUsage(AnalysisUsage &AU) const override;
bool runOnFunction(Function &F) override;
};
/// This pass performs the global (interprocedural) stack safety analysis (new
/// pass manager).
class StackSafetyGlobalAnalysis
: public AnalysisInfoMixin<StackSafetyGlobalAnalysis> {
friend AnalysisInfoMixin<StackSafetyGlobalAnalysis>;
static AnalysisKey Key;
public:
using Result = StackSafetyGlobalInfo;
Result run(Module &M, ModuleAnalysisManager &AM);
};
/// Printer pass for the \c StackSafetyGlobalAnalysis results.
class StackSafetyGlobalPrinterPass
: public PassInfoMixin<StackSafetyGlobalPrinterPass> {
raw_ostream &OS;
public:
explicit StackSafetyGlobalPrinterPass(raw_ostream &OS) : OS(OS) {}
PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM);
};
/// This pass performs the global (interprocedural) stack safety analysis
/// (legacy pass manager).
class StackSafetyGlobalInfoWrapperPass : public ModulePass {
StackSafetyGlobalInfo SSGI;
public:
static char ID;
StackSafetyGlobalInfoWrapperPass();
~StackSafetyGlobalInfoWrapperPass();
const StackSafetyGlobalInfo &getResult() const { return SSGI; }
void print(raw_ostream &O, const Module *M) const override;
void getAnalysisUsage(AnalysisUsage &AU) const override;
bool runOnModule(Module &M) override;
};
bool needsParamAccessSummary(const Module &M);
void generateParamAccessSummary(ModuleSummaryIndex &Index);
} // end namespace llvm
#endif // LLVM_ANALYSIS_STACKSAFETYANALYSIS_H
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