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//===--- RedundantControlFlowCheck.cpp - clang-tidy------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "RedundantControlFlowCheck.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/Lex/Lexer.h"
using namespace clang::ast_matchers;
namespace clang::tidy::readability {
namespace {
const char *const RedundantReturnDiag = "redundant return statement at the end "
"of a function with a void return type";
const char *const RedundantContinueDiag = "redundant continue statement at the "
"end of loop statement";
bool isLocationInMacroExpansion(const SourceManager &SM, SourceLocation Loc) {
return SM.isMacroBodyExpansion(Loc) || SM.isMacroArgExpansion(Loc);
}
} // namespace
void RedundantControlFlowCheck::registerMatchers(MatchFinder *Finder) {
Finder->addMatcher(
functionDecl(isDefinition(), returns(voidType()),
hasBody(compoundStmt(hasAnySubstatement(
returnStmt(unless(has(expr())))))
.bind("return"))),
this);
Finder->addMatcher(
mapAnyOf(forStmt, cxxForRangeStmt, whileStmt, doStmt)
.with(hasBody(compoundStmt(hasAnySubstatement(continueStmt()))
.bind("continue"))),
this);
}
void RedundantControlFlowCheck::check(const MatchFinder::MatchResult &Result) {
if (const auto *Return = Result.Nodes.getNodeAs<CompoundStmt>("return"))
checkRedundantReturn(Result, Return);
else if (const auto *Continue =
Result.Nodes.getNodeAs<CompoundStmt>("continue"))
checkRedundantContinue(Result, Continue);
}
void RedundantControlFlowCheck::checkRedundantReturn(
const MatchFinder::MatchResult &Result, const CompoundStmt *Block) {
CompoundStmt::const_reverse_body_iterator Last = Block->body_rbegin();
if (const auto *Return = dyn_cast<ReturnStmt>(*Last))
issueDiagnostic(Result, Block, Return->getSourceRange(),
RedundantReturnDiag);
}
void RedundantControlFlowCheck::checkRedundantContinue(
const MatchFinder::MatchResult &Result, const CompoundStmt *Block) {
CompoundStmt::const_reverse_body_iterator Last = Block->body_rbegin();
if (const auto *Continue = dyn_cast<ContinueStmt>(*Last))
issueDiagnostic(Result, Block, Continue->getSourceRange(),
RedundantContinueDiag);
}
void RedundantControlFlowCheck::issueDiagnostic(
const MatchFinder::MatchResult &Result, const CompoundStmt *const Block,
const SourceRange &StmtRange, const char *const Diag) {
SourceManager &SM = *Result.SourceManager;
if (isLocationInMacroExpansion(SM, StmtRange.getBegin()))
return;
CompoundStmt::const_reverse_body_iterator Previous = ++Block->body_rbegin();
SourceLocation Start;
if (Previous != Block->body_rend())
Start = Lexer::findLocationAfterToken(
cast<Stmt>(*Previous)->getEndLoc(), tok::semi, SM, getLangOpts(),
/*SkipTrailingWhitespaceAndNewLine=*/true);
if (!Start.isValid())
Start = StmtRange.getBegin();
auto RemovedRange = CharSourceRange::getCharRange(
Start, Lexer::findLocationAfterToken(
StmtRange.getEnd(), tok::semi, SM, getLangOpts(),
/*SkipTrailingWhitespaceAndNewLine=*/true));
diag(StmtRange.getBegin(), Diag) << FixItHint::CreateRemoval(RemovedRange);
}
} // namespace clang::tidy::readability
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