clang-tools  14.0.0git
RedundantControlFlowCheck.cpp
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1 //===--- RedundantControlFlowCheck.cpp - clang-tidy------------------------===//
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 
10 #include "clang/AST/ASTContext.h"
11 #include "clang/ASTMatchers/ASTMatchFinder.h"
12 #include "clang/Lex/Lexer.h"
13 
14 using namespace clang::ast_matchers;
15 
16 namespace clang {
17 namespace tidy {
18 namespace readability {
19 
20 namespace {
21 
22 const char *const RedundantReturnDiag = "redundant return statement at the end "
23  "of a function with a void return type";
24 const char *const RedundantContinueDiag = "redundant continue statement at the "
25  "end of loop statement";
26 
27 bool isLocationInMacroExpansion(const SourceManager &SM, SourceLocation Loc) {
28  return SM.isMacroBodyExpansion(Loc) || SM.isMacroArgExpansion(Loc);
29 }
30 
31 } // namespace
32 
33 void RedundantControlFlowCheck::registerMatchers(MatchFinder *Finder) {
34  Finder->addMatcher(
35  functionDecl(isDefinition(), returns(voidType()),
36  hasBody(compoundStmt(hasAnySubstatement(
37  returnStmt(unless(has(expr())))))
38  .bind("return"))),
39  this);
40  Finder->addMatcher(
41  mapAnyOf(forStmt, cxxForRangeStmt, whileStmt, doStmt)
42  .with(hasBody(compoundStmt(hasAnySubstatement(continueStmt()))
43  .bind("continue"))),
44  this);
45 }
46 
47 void RedundantControlFlowCheck::check(const MatchFinder::MatchResult &Result) {
48  if (const auto *Return = Result.Nodes.getNodeAs<CompoundStmt>("return"))
49  checkRedundantReturn(Result, Return);
50  else if (const auto *Continue =
51  Result.Nodes.getNodeAs<CompoundStmt>("continue"))
52  checkRedundantContinue(Result, Continue);
53 }
54 
55 void RedundantControlFlowCheck::checkRedundantReturn(
56  const MatchFinder::MatchResult &Result, const CompoundStmt *Block) {
57  CompoundStmt::const_reverse_body_iterator Last = Block->body_rbegin();
58  if (const auto *Return = dyn_cast<ReturnStmt>(*Last))
59  issueDiagnostic(Result, Block, Return->getSourceRange(),
60  RedundantReturnDiag);
61 }
62 
63 void RedundantControlFlowCheck::checkRedundantContinue(
64  const MatchFinder::MatchResult &Result, const CompoundStmt *Block) {
65  CompoundStmt::const_reverse_body_iterator Last = Block->body_rbegin();
66  if (const auto *Continue = dyn_cast<ContinueStmt>(*Last))
67  issueDiagnostic(Result, Block, Continue->getSourceRange(),
68  RedundantContinueDiag);
69 }
70 
71 void RedundantControlFlowCheck::issueDiagnostic(
72  const MatchFinder::MatchResult &Result, const CompoundStmt *const Block,
73  const SourceRange &StmtRange, const char *const Diag) {
74  SourceManager &SM = *Result.SourceManager;
75  if (isLocationInMacroExpansion(SM, StmtRange.getBegin()))
76  return;
77 
78  CompoundStmt::const_reverse_body_iterator Previous = ++Block->body_rbegin();
79  SourceLocation Start;
80  if (Previous != Block->body_rend())
81  Start = Lexer::findLocationAfterToken(
82  dyn_cast<Stmt>(*Previous)->getEndLoc(), tok::semi, SM, getLangOpts(),
83  /*SkipTrailingWhitespaceAndNewLine=*/true);
84  if (!Start.isValid())
85  Start = StmtRange.getBegin();
86  auto RemovedRange = CharSourceRange::getCharRange(
87  Start, Lexer::findLocationAfterToken(
88  StmtRange.getEnd(), tok::semi, SM, getLangOpts(),
89  /*SkipTrailingWhitespaceAndNewLine=*/true));
90 
91  diag(StmtRange.getBegin(), Diag) << FixItHint::CreateRemoval(RemovedRange);
92 }
93 
94 } // namespace readability
95 } // namespace tidy
96 } // namespace clang
Loc
SourceLocation Loc
Definition: KernelNameRestrictionCheck.cpp:45
clang::ast_matchers
Definition: AbseilMatcher.h:14
clang::clangd::check
bool check(llvm::StringRef File, llvm::function_ref< bool(const Position &)> ShouldCheckLine, const ThreadsafeFS &TFS, const ClangdLSPServer::Options &Opts, bool EnableCodeCompletion)
Definition: Check.cpp:258
clang
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Definition: ApplyReplacements.h:27
RedundantControlFlowCheck.h