1 //===-- Transfer.h ----------------------------------------------*- 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 defines a transfer function that evaluates a program statement and
10 //  updates an environment accordingly.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_TRANSFER_H
15 #define LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_TRANSFER_H
16 
17 #include "clang/AST/Stmt.h"
18 #include "clang/Analysis/FlowSensitive/DataflowAnalysisContext.h"
19 #include "clang/Analysis/FlowSensitive/DataflowEnvironment.h"
20 #include "clang/Analysis/FlowSensitive/TypeErasedDataflowAnalysis.h"
21 
22 namespace clang {
23 namespace dataflow {
24 
25 /// Maps statements to the environments of basic blocks that contain them.
26 class StmtToEnvMap {
27 public:
28   // `CurBlockID` is the ID of the block currently being processed, and
29   // `CurState` is the pending state currently associated with this block. These
30   // are supplied separately as the pending state for the current block may not
31   // yet be represented in `BlockToState`.
32   StmtToEnvMap(const ControlFlowContext &CFCtx,
33                llvm::ArrayRef<std::optional<TypeErasedDataflowAnalysisState>>
34                    BlockToState,
35                unsigned CurBlockID,
36                const TypeErasedDataflowAnalysisState &CurState)
37       : CFCtx(CFCtx), BlockToState(BlockToState), CurBlockID(CurBlockID),
38         CurState(CurState) {}
39 
40   /// Returns the environment of the basic block that contains `S`.
41   /// The result is guaranteed never to be null.
42   const Environment *getEnvironment(const Stmt &S) const;
43 
44 private:
45   const ControlFlowContext &CFCtx;
46   llvm::ArrayRef<std::optional<TypeErasedDataflowAnalysisState>> BlockToState;
47   unsigned CurBlockID;
48   const TypeErasedDataflowAnalysisState &CurState;
49 };
50 
51 /// Evaluates `S` and updates `Env` accordingly.
52 ///
53 /// Requirements:
54 ///
55 ///  `S` must not be `ParenExpr` or `ExprWithCleanups`.
56 void transfer(const StmtToEnvMap &StmtToEnv, const Stmt &S, Environment &Env);
57 
58 } // namespace dataflow
59 } // namespace clang
60 
61 #endif // LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_TRANSFER_H
62