1//===-- ControlFlowContext.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 ControlFlowContext class that is used by dataflow
10//  analyses that run over Control-Flow Graphs (CFGs).
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_CONTROLFLOWCONTEXT_H
15#define LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_CONTROLFLOWCONTEXT_H
16
17#include "clang/AST/ASTContext.h"
18#include "clang/AST/Decl.h"
19#include "clang/AST/Stmt.h"
20#include "clang/Analysis/CFG.h"
21#include "llvm/ADT/BitVector.h"
22#include "llvm/ADT/DenseMap.h"
23#include "llvm/Support/Error.h"
24#include <memory>
25#include <utility>
26
27namespace clang {
28namespace dataflow {
29
30/// Holds CFG and other derived context that is needed to perform dataflow
31/// analysis.
32class ControlFlowContext {
33public:
34  /// Builds a ControlFlowContext from a `FunctionDecl`.
35  /// `Func.doesThisDeclarationHaveABody()` must be true, and
36  /// `Func.isTemplated()` must be false.
37  static llvm::Expected<ControlFlowContext> build(const FunctionDecl &Func);
38
39  /// Builds a ControlFlowContext from an AST node. `D` is the function in which
40  /// `S` resides. `D.isTemplated()` must be false.
41  static llvm::Expected<ControlFlowContext> build(const Decl &D, Stmt &S,
42                                                  ASTContext &C);
43
44  /// Returns the `Decl` containing the statement used to construct the CFG, if
45  /// available.
46  const Decl &getDecl() const { return ContainingDecl; }
47
48  /// Returns the CFG that is stored in this context.
49  const CFG &getCFG() const { return *Cfg; }
50
51  /// Returns a mapping from statements to basic blocks that contain them.
52  const llvm::DenseMap<const Stmt *, const CFGBlock *> &getStmtToBlock() const {
53    return StmtToBlock;
54  }
55
56  /// Returns whether `B` is reachable from the entry block.
57  bool isBlockReachable(const CFGBlock &B) const {
58    return BlockReachable[B.getBlockID()];
59  }
60
61private:
62  ControlFlowContext(const Decl &D, std::unique_ptr<CFG> Cfg,
63                     llvm::DenseMap<const Stmt *, const CFGBlock *> StmtToBlock,
64                     llvm::BitVector BlockReachable)
65      : ContainingDecl(D), Cfg(std::move(Cfg)),
66        StmtToBlock(std::move(StmtToBlock)),
67        BlockReachable(std::move(BlockReachable)) {}
68
69  /// The `Decl` containing the statement used to construct the CFG.
70  const Decl &ContainingDecl;
71  std::unique_ptr<CFG> Cfg;
72  llvm::DenseMap<const Stmt *, const CFGBlock *> StmtToBlock;
73  llvm::BitVector BlockReachable;
74};
75
76} // namespace dataflow
77} // namespace clang
78
79#endif // LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_CONTROLFLOWCONTEXT_H
80