/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/include/clang/Analysis/Analyses/LiveVariables.h
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1 | | //===- LiveVariables.h - Live Variable Analysis for Source CFGs -*- 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 | | // This file implements Live Variables analysis for source-level CFGs. |
10 | | // |
11 | | //===----------------------------------------------------------------------===// |
12 | | |
13 | | #ifndef LLVM_CLANG_ANALYSIS_ANALYSES_LIVEVARIABLES_H |
14 | | #define LLVM_CLANG_ANALYSIS_ANALYSES_LIVEVARIABLES_H |
15 | | |
16 | | #include "clang/AST/Decl.h" |
17 | | #include "clang/Analysis/AnalysisDeclContext.h" |
18 | | #include "llvm/ADT/ImmutableSet.h" |
19 | | |
20 | | namespace clang { |
21 | | |
22 | | class CFG; |
23 | | class CFGBlock; |
24 | | class Stmt; |
25 | | class DeclRefExpr; |
26 | | class SourceManager; |
27 | | |
28 | | class LiveVariables : public ManagedAnalysis { |
29 | | public: |
30 | | class LivenessValues { |
31 | | public: |
32 | | |
33 | | llvm::ImmutableSet<const Expr *> liveExprs; |
34 | | llvm::ImmutableSet<const VarDecl *> liveDecls; |
35 | | llvm::ImmutableSet<const BindingDecl *> liveBindings; |
36 | | |
37 | | bool equals(const LivenessValues &V) const; |
38 | | |
39 | | LivenessValues() |
40 | 768k | : liveExprs(nullptr), liveDecls(nullptr), liveBindings(nullptr) {} |
41 | | |
42 | | LivenessValues(llvm::ImmutableSet<const Expr *> liveExprs, |
43 | | llvm::ImmutableSet<const VarDecl *> LiveDecls, |
44 | | llvm::ImmutableSet<const BindingDecl *> LiveBindings) |
45 | | : liveExprs(liveExprs), liveDecls(LiveDecls), |
46 | 82.7k | liveBindings(LiveBindings) {} |
47 | | |
48 | | bool isLive(const Expr *E) const; |
49 | | bool isLive(const VarDecl *D) const; |
50 | | |
51 | | friend class LiveVariables; |
52 | | }; |
53 | | |
54 | | class Observer { |
55 | | virtual void anchor(); |
56 | | public: |
57 | 519 | virtual ~Observer() {} |
58 | | |
59 | | /// A callback invoked right before invoking the |
60 | | /// liveness transfer function on the given statement. |
61 | | virtual void observeStmt(const Stmt *S, |
62 | | const CFGBlock *currentBlock, |
63 | 0 | const LivenessValues& V) {} |
64 | | |
65 | | /// Called when the live variables analysis registers |
66 | | /// that a variable is killed. |
67 | 361 | virtual void observerKill(const DeclRefExpr *DR) {} |
68 | | }; |
69 | | |
70 | | ~LiveVariables() override; |
71 | | |
72 | | /// Compute the liveness information for a given CFG. |
73 | | static std::unique_ptr<LiveVariables> |
74 | | computeLiveness(AnalysisDeclContext &analysisContext, bool killAtAssign); |
75 | | |
76 | | /// Return true if a variable is live at the end of a |
77 | | /// specified block. |
78 | | bool isLive(const CFGBlock *B, const VarDecl *D); |
79 | | |
80 | | /// Returns true if a variable is live at the beginning of the |
81 | | /// the statement. This query only works if liveness information |
82 | | /// has been recorded at the statement level (see runOnAllBlocks), and |
83 | | /// only returns liveness information for block-level expressions. |
84 | | bool isLive(const Stmt *S, const VarDecl *D); |
85 | | |
86 | | /// Returns true the block-level expression value is live |
87 | | /// before the given block-level expression (see runOnAllBlocks). |
88 | | bool isLive(const Stmt *Loc, const Expr *Val); |
89 | | |
90 | | /// Print to stderr the variable liveness information associated with |
91 | | /// each basic block. |
92 | | void dumpBlockLiveness(const SourceManager &M); |
93 | | |
94 | | /// Print to stderr the expression liveness information associated with |
95 | | /// each basic block. |
96 | | void dumpExprLiveness(const SourceManager &M); |
97 | | |
98 | | void runOnAllBlocks(Observer &obs); |
99 | | |
100 | | static std::unique_ptr<LiveVariables> |
101 | 521 | create(AnalysisDeclContext &analysisContext) { |
102 | 521 | return computeLiveness(analysisContext, true); |
103 | 521 | } |
104 | | |
105 | | static const void *getTag(); |
106 | | |
107 | | private: |
108 | | LiveVariables(void *impl); |
109 | | void *impl; |
110 | | }; |
111 | | |
112 | | class RelaxedLiveVariables : public LiveVariables { |
113 | | public: |
114 | | static std::unique_ptr<LiveVariables> |
115 | 26.6k | create(AnalysisDeclContext &analysisContext) { |
116 | 26.6k | return computeLiveness(analysisContext, false); |
117 | 26.6k | } |
118 | | |
119 | | static const void *getTag(); |
120 | | }; |
121 | | |
122 | | } // end namespace clang |
123 | | |
124 | | #endif |