forked from OSchip/llvm-project
102 lines
3.7 KiB
C++
102 lines
3.7 KiB
C++
//===--- UnusedRaiiCheck.cpp - clang-tidy ---------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "UnusedRaiiCheck.h"
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#include "clang/AST/ASTContext.h"
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#include "clang/Lex/Lexer.h"
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using namespace clang::ast_matchers;
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namespace clang {
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namespace tidy {
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namespace bugprone {
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namespace {
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AST_MATCHER(CXXRecordDecl, hasNonTrivialDestructor) {
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// TODO: If the dtor is there but empty we don't want to warn either.
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return Node.hasDefinition() && Node.hasNonTrivialDestructor();
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}
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} // namespace
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void UnusedRaiiCheck::registerMatchers(MatchFinder *Finder) {
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// Look for temporaries that are constructed in-place and immediately
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// destroyed.
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Finder->addMatcher(
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mapAnyOf(cxxConstructExpr, cxxUnresolvedConstructExpr)
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.with(hasParent(compoundStmt().bind("compound")),
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anyOf(hasType(hasCanonicalType(recordType(hasDeclaration(
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cxxRecordDecl(hasNonTrivialDestructor()))))),
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hasType(hasCanonicalType(templateSpecializationType(
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hasDeclaration(classTemplateDecl(has(
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cxxRecordDecl(hasNonTrivialDestructor())))))))))
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.bind("expr"),
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this);
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}
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template <typename T>
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void reportDiagnostic(DiagnosticBuilder D, const T *Node, SourceRange SR,
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bool DefaultConstruction) {
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const char *Replacement = " give_me_a_name";
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// If this is a default ctor we have to remove the parens or we'll introduce a
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// most vexing parse.
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if (DefaultConstruction) {
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D << FixItHint::CreateReplacement(CharSourceRange::getTokenRange(SR),
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Replacement);
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return;
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}
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// Otherwise just suggest adding a name. To find the place to insert the name
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// find the first TypeLoc in the children of E, which always points to the
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// written type.
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D << FixItHint::CreateInsertion(SR.getBegin(), Replacement);
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}
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void UnusedRaiiCheck::check(const MatchFinder::MatchResult &Result) {
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const auto *E = Result.Nodes.getNodeAs<Expr>("expr");
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// We ignore code expanded from macros to reduce the number of false
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// positives.
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if (E->getBeginLoc().isMacroID())
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return;
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// Don't emit a warning for the last statement in the surrounding compound
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// statement.
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const auto *CS = Result.Nodes.getNodeAs<CompoundStmt>("compound");
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const auto *LastExpr = dyn_cast<Expr>(CS->body_back());
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if (LastExpr && E == LastExpr->IgnoreUnlessSpelledInSource())
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return;
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// Emit a warning.
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auto D = diag(E->getBeginLoc(), "object destroyed immediately after "
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"creation; did you mean to name the object?");
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if (const auto *Node = dyn_cast<CXXConstructExpr>(E))
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reportDiagnostic(D, Node, Node->getParenOrBraceRange(),
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Node->getNumArgs() == 0 ||
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isa<CXXDefaultArgExpr>(Node->getArg(0)));
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if (const auto *Node = dyn_cast<CXXUnresolvedConstructExpr>(E)) {
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auto SR = SourceRange(Node->getLParenLoc(), Node->getRParenLoc());
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auto DefaultConstruction = Node->getNumArgs() == 0;
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if (!DefaultConstruction) {
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auto *FirstArg = Node->getArg(0);
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DefaultConstruction = isa<CXXDefaultArgExpr>(FirstArg);
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if (auto *ILE = dyn_cast<InitListExpr>(FirstArg)) {
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DefaultConstruction = ILE->getNumInits() == 0;
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SR = SourceRange(ILE->getLBraceLoc(), ILE->getRBraceLoc());
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}
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}
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reportDiagnostic(D, Node, SR, DefaultConstruction);
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}
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}
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} // namespace bugprone
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} // namespace tidy
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} // namespace clang
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