1//===- StackSafetyAnalysis.h - Stack memory safety analysis -----*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// Stack Safety Analysis detects allocas and arguments with safe access.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_ANALYSIS_STACKSAFETYANALYSIS_H
14#define LLVM_ANALYSIS_STACKSAFETYANALYSIS_H
15
16#include "llvm/IR/ModuleSummaryIndex.h"
17#include "llvm/IR/PassManager.h"
18#include "llvm/Pass.h"
19
20namespace llvm {
21
22class AllocaInst;
23class ScalarEvolution;
24
25/// Interface to access stack safety analysis results for single function.
26class StackSafetyInfo {
27public:
28 struct InfoTy;
29
30private:
31 Function *F = nullptr;
32 std::function<ScalarEvolution &()> GetSE;
33 mutable std::unique_ptr<InfoTy> Info;
34
35public:
36 StackSafetyInfo();
37 StackSafetyInfo(Function *F, std::function<ScalarEvolution &()> GetSE);
38 StackSafetyInfo(StackSafetyInfo &&);
39 StackSafetyInfo &operator=(StackSafetyInfo &&);
40 ~StackSafetyInfo();
41
42 const InfoTy &getInfo() const;
43
44 // TODO: Add useful for client methods.
45 void print(raw_ostream &O) const;
46
47 /// Parameters use for a FunctionSummary.
48 /// Function collects access information of all pointer parameters.
49 /// Information includes a range of direct access of parameters by the
50 /// functions and all call sites accepting the parameter.
51 /// StackSafety assumes that missing parameter information means possibility
52 /// of access to the parameter with any offset, so we can correctly link
53 /// code without StackSafety information, e.g. non-ThinLTO.
54 std::vector<FunctionSummary::ParamAccess>
55 getParamAccesses(ModuleSummaryIndex &Index) const;
56};
57
58class StackSafetyGlobalInfo {
59public:
60 struct InfoTy;
61
62private:
63 Module *M = nullptr;
64 std::function<const StackSafetyInfo &(Function &F)> GetSSI;
65 const ModuleSummaryIndex *Index = nullptr;
66 mutable std::unique_ptr<InfoTy> Info;
67 const InfoTy &getInfo() const;
68
69public:
70 StackSafetyGlobalInfo();
71 StackSafetyGlobalInfo(
72 Module *M, std::function<const StackSafetyInfo &(Function &F)> GetSSI,
73 const ModuleSummaryIndex *Index);
74 StackSafetyGlobalInfo(StackSafetyGlobalInfo &&);
75 StackSafetyGlobalInfo &operator=(StackSafetyGlobalInfo &&);
76 ~StackSafetyGlobalInfo();
77
78 // Whether we can prove that all accesses to this Alloca are in-range and
79 // during its lifetime.
80 bool isSafe(const AllocaInst &AI) const;
81
82 // Returns true if the instruction can be proven to do only two types of
83 // memory accesses:
84 // (1) live stack locations in-bounds or
85 // (2) non-stack locations.
86 bool stackAccessIsSafe(const Instruction &I) const;
87 void print(raw_ostream &O) const;
88 void dump() const;
89};
90
91/// StackSafetyInfo wrapper for the new pass manager.
92class StackSafetyAnalysis : public AnalysisInfoMixin<StackSafetyAnalysis> {
93 friend AnalysisInfoMixin<StackSafetyAnalysis>;
94 static AnalysisKey Key;
95
96public:
97 using Result = StackSafetyInfo;
98 StackSafetyInfo run(Function &F, FunctionAnalysisManager &AM);
99};
100
101/// Printer pass for the \c StackSafetyAnalysis results.
102class StackSafetyPrinterPass : public PassInfoMixin<StackSafetyPrinterPass> {
103 raw_ostream &OS;
104
105public:
106 explicit StackSafetyPrinterPass(raw_ostream &OS) : OS(OS) {}
107 PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
108 static bool isRequired() { return true; }
109};
110
111/// StackSafetyInfo wrapper for the legacy pass manager
112class StackSafetyInfoWrapperPass : public FunctionPass {
113 StackSafetyInfo SSI;
114
115public:
116 static char ID;
117 StackSafetyInfoWrapperPass();
118
119 const StackSafetyInfo &getResult() const { return SSI; }
120
121 void print(raw_ostream &O, const Module *M) const override;
122 void getAnalysisUsage(AnalysisUsage &AU) const override;
123
124 bool runOnFunction(Function &F) override;
125};
126
127/// This pass performs the global (interprocedural) stack safety analysis (new
128/// pass manager).
129class StackSafetyGlobalAnalysis
130 : public AnalysisInfoMixin<StackSafetyGlobalAnalysis> {
131 friend AnalysisInfoMixin<StackSafetyGlobalAnalysis>;
132 static AnalysisKey Key;
133
134public:
135 using Result = StackSafetyGlobalInfo;
136 Result run(Module &M, ModuleAnalysisManager &AM);
137};
138
139/// Printer pass for the \c StackSafetyGlobalAnalysis results.
140class StackSafetyGlobalPrinterPass
141 : public PassInfoMixin<StackSafetyGlobalPrinterPass> {
142 raw_ostream &OS;
143
144public:
145 explicit StackSafetyGlobalPrinterPass(raw_ostream &OS) : OS(OS) {}
146 PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM);
147 static bool isRequired() { return true; }
148};
149
150/// This pass performs the global (interprocedural) stack safety analysis
151/// (legacy pass manager).
152class StackSafetyGlobalInfoWrapperPass : public ModulePass {
153 StackSafetyGlobalInfo SSGI;
154
155public:
156 static char ID;
157
158 StackSafetyGlobalInfoWrapperPass();
159 ~StackSafetyGlobalInfoWrapperPass();
160
161 const StackSafetyGlobalInfo &getResult() const { return SSGI; }
162
163 void print(raw_ostream &O, const Module *M) const override;
164 void getAnalysisUsage(AnalysisUsage &AU) const override;
165
166 bool runOnModule(Module &M) override;
167};
168
169bool needsParamAccessSummary(const Module &M);
170
171void generateParamAccessSummary(ModuleSummaryIndex &Index);
172
173} // end namespace llvm
174
175#endif // LLVM_ANALYSIS_STACKSAFETYANALYSIS_H
176

source code of llvm/include/llvm/Analysis/StackSafetyAnalysis.h