Details | Last modification | View Log | RSS feed
| Rev | Author | Line No. | Line |
|---|---|---|---|
| 14 | pmbaty | 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 | : 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 | 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 | 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 | const LivenessValues& V) {} |
||
| 64 | |||
| 65 | /// Called when the live variables analysis registers |
||
| 66 | /// that a variable is killed. |
||
| 67 | 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 | create(AnalysisDeclContext &analysisContext) { |
||
| 102 | return computeLiveness(analysisContext, true); |
||
| 103 | } |
||
| 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 | create(AnalysisDeclContext &analysisContext) { |
||
| 116 | return computeLiveness(analysisContext, false); |
||
| 117 | } |
||
| 118 | |||
| 119 | static const void *getTag(); |
||
| 120 | }; |
||
| 121 | |||
| 122 | } // end namespace clang |
||
| 123 | |||
| 124 | #endif |