1 //===- ControlFlowContext.cpp ---------------------------------------------===//
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 #include "clang/Analysis/FlowSensitive/ControlFlowContext.h"
15 #include "clang/AST/ASTContext.h"
16 #include "clang/AST/Decl.h"
17 #include "clang/AST/Stmt.h"
18 #include "clang/Analysis/CFG.h"
19 #include "llvm/ADT/DenseMap.h"
20 #include "llvm/Support/Error.h"
21 #include <utility>
22
23 namespace clang {
24 namespace dataflow {
25
26 /// Returns a map from statements to basic blocks that contain them.
27 static llvm::DenseMap<const Stmt *, const CFGBlock *>
buildStmtToBasicBlockMap(const CFG & Cfg)28 buildStmtToBasicBlockMap(const CFG &Cfg) {
29 llvm::DenseMap<const Stmt *, const CFGBlock *> StmtToBlock;
30 for (const CFGBlock *Block : Cfg) {
31 if (Block == nullptr)
32 continue;
33
34 for (const CFGElement &Element : *Block) {
35 auto Stmt = Element.getAs<CFGStmt>();
36 if (!Stmt)
37 continue;
38
39 StmtToBlock[Stmt->getStmt()] = Block;
40 }
41 if (const Stmt *TerminatorStmt = Block->getTerminatorStmt())
42 StmtToBlock[TerminatorStmt] = Block;
43 }
44 return StmtToBlock;
45 }
46
47 llvm::Expected<ControlFlowContext>
build(const Decl * D,Stmt & S,ASTContext & C)48 ControlFlowContext::build(const Decl *D, Stmt &S, ASTContext &C) {
49 CFG::BuildOptions Options;
50 Options.PruneTriviallyFalseEdges = false;
51 Options.AddImplicitDtors = true;
52 Options.AddTemporaryDtors = true;
53 Options.AddInitializers = true;
54 Options.AddCXXDefaultInitExprInCtors = true;
55
56 // Ensure that all sub-expressions in basic blocks are evaluated.
57 Options.setAllAlwaysAdd();
58
59 auto Cfg = CFG::buildCFG(D, &S, &C, Options);
60 if (Cfg == nullptr)
61 return llvm::createStringError(
62 std::make_error_code(std::errc::invalid_argument),
63 "CFG::buildCFG failed");
64
65 llvm::DenseMap<const Stmt *, const CFGBlock *> StmtToBlock =
66 buildStmtToBasicBlockMap(*Cfg);
67 return ControlFlowContext(D, std::move(Cfg), std::move(StmtToBlock));
68 }
69
70 } // namespace dataflow
71 } // namespace clang
72