clang-tools-extra/clang-tidy/readability/UseAnyOfAllOfCheck.cpp

   1 //===--- UseAnyOfAllOfCheck.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
   9 #include "UseAnyOfAllOfCheck.h"
  10 #include "clang/AST/ASTContext.h"
  11 #include "clang/ASTMatchers/ASTMatchFinder.h"
  12 #include "clang/Analysis/Analyses/ExprMutationAnalyzer.h"
  13 #include "clang/Frontend/CompilerInstance.h"
  14
  15 using namespace clang::ast_matchers;
  16
  17 namespace clang {
  18 namespace {
  19 /// Matches a Stmt whose parent is a CompoundStmt, and which is directly
  20 /// followed by a Stmt matching the inner matcher.
  21 AST_MATCHER_P(Stmt, nextStmt, ast_matchers::internal::Matcher<Stmt>,
  22               InnerMatcher) {
  23   DynTypedNodeList Parents = Finder->getASTContext().getParents(Node);
  24   if (Parents.size() != 1)
  25     return false;
  26
  27   auto *C = Parents[0].get<CompoundStmt>();
  28   if (!C)
  29     return false;
  30
  31   const auto *I = llvm::find(C->body(), &Node);
  32   assert(I != C->body_end() && "C is parent of Node");
  33   if (++I == C->body_end())
  34     return false; // Node is last statement.
  35
  36   return InnerMatcher.matches(**I, Finder, Builder);
  37 }
  38 } // namespace
  39
  40 namespace tidy::readability {
  41
  42 void UseAnyOfAllOfCheck::registerMatchers(MatchFinder *Finder) {
  43   auto Returns = [](bool V) {
  44     return returnStmt(hasReturnValue(cxxBoolLiteral(equals(V))));
  45   };
  46
  47   auto ReturnsButNotTrue =
  48       returnStmt(hasReturnValue(unless(cxxBoolLiteral(equals(true)))));
  49   auto ReturnsButNotFalse =
  50       returnStmt(hasReturnValue(unless(cxxBoolLiteral(equals(false)))));
  51
  52   Finder->addMatcher(
  53       cxxForRangeStmt(
  54           nextStmt(Returns(false).bind("final_return")),
  55           hasBody(allOf(hasDescendant(Returns(true)),
  56                         unless(anyOf(hasDescendant(breakStmt()),
  57                                      hasDescendant(gotoStmt()),
  58                                      hasDescendant(ReturnsButNotTrue))))))
  59           .bind("any_of_loop"),
  60       this);
  61
  62   Finder->addMatcher(
  63       cxxForRangeStmt(
  64           nextStmt(Returns(true).bind("final_return")),
  65           hasBody(allOf(hasDescendant(Returns(false)),
  66                         unless(anyOf(hasDescendant(breakStmt()),
  67                                      hasDescendant(gotoStmt()),
  68                                      hasDescendant(ReturnsButNotFalse))))))
  69           .bind("all_of_loop"),
  70       this);
  71 }
  72
  73 static bool isViableLoop(const CXXForRangeStmt &S, ASTContext &Context) {
  74
  75   ExprMutationAnalyzer Mutations(*S.getBody(), Context);
  76   if (Mutations.isMutated(S.getLoopVariable()))
  77     return false;
  78   const auto Matches =
  79       match(findAll(declRefExpr().bind("decl_ref")), *S.getBody(), Context);
  80
  81   return llvm::none_of(Matches, [&Mutations](auto &DeclRef) {
  82     // TODO: allow modifications of loop-local variables
  83     return Mutations.isMutated(
  84         DeclRef.template getNodeAs<DeclRefExpr>("decl_ref")->getDecl());
  85   });
  86 }
  87
  88 void UseAnyOfAllOfCheck::check(const MatchFinder::MatchResult &Result) {
  89
  90   if (const auto *S = Result.Nodes.getNodeAs<CXXForRangeStmt>("any_of_loop")) {
  91     if (!isViableLoop(*S, *Result.Context))
  92       return;
  93
  94     diag(S->getForLoc(), "replace loop by 'std%select{|::ranges}0::any_of()'")
  95         << getLangOpts().CPlusPlus20;
  96   } else if (const auto *S =
  97                  Result.Nodes.getNodeAs<CXXForRangeStmt>("all_of_loop")) {
  98     if (!isViableLoop(*S, *Result.Context))
  99       return;
 100
 101     diag(S->getForLoc(), "replace loop by 'std%select{|::ranges}0::all_of()'")
 102         << getLangOpts().CPlusPlus20;
 103   }
 104 }
 105
 106 } // namespace tidy::readability
 107 } // namespace clang