forked from OSchip/llvm-project
92 lines
3.2 KiB
C++
92 lines
3.2 KiB
C++
//===--- UnusedRAIICheck.cpp - clang-tidy ---------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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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 {
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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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namespace tidy {
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namespace misc {
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void UnusedRAIICheck::registerMatchers(MatchFinder *Finder) {
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// Only register the matchers for C++; the functionality currently does not
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// provide any benefit to other languages, despite being benign.
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if (!getLangOpts().CPlusPlus)
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return;
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// Look for temporaries that are constructed in-place and immediately
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// destroyed. Look for temporaries created by a functional cast but not for
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// those returned from a call.
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auto BindTemp = cxxBindTemporaryExpr(unless(has(callExpr()))).bind("temp");
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Finder->addMatcher(
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exprWithCleanups(
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unless(isInTemplateInstantiation()),
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hasParent(compoundStmt().bind("compound")),
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hasType(cxxRecordDecl(hasNonTrivialDestructor())),
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anyOf(has(BindTemp), has(cxxFunctionalCastExpr(has(BindTemp)))))
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.bind("expr"),
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this);
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}
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void UnusedRAIICheck::check(const MatchFinder::MatchResult &Result) {
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const auto *E = Result.Nodes.getStmtAs<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->getLocStart().isMacroID())
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return;
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// Don't emit a warning for the last statement in the surrounding compund
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// statement.
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const auto *CS = Result.Nodes.getStmtAs<CompoundStmt>("compound");
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if (E == CS->body_back())
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return;
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// Emit a warning.
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auto D = diag(E->getLocStart(), "object destroyed immediately after "
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"creation; did you mean to name the object?");
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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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const auto *BTE = Result.Nodes.getStmtAs<CXXBindTemporaryExpr>("temp");
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if (const auto *TOE = dyn_cast<CXXTemporaryObjectExpr>(BTE->getSubExpr()))
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if (TOE->getNumArgs() == 0) {
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D << FixItHint::CreateReplacement(
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CharSourceRange::getTokenRange(TOE->getParenOrBraceRange()),
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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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auto Matches =
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match(expr(hasDescendant(typeLoc().bind("t"))), *E, *Result.Context);
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const auto *TL = selectFirst<TypeLoc>("t", Matches);
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D << FixItHint::CreateInsertion(
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Lexer::getLocForEndOfToken(TL->getLocEnd(), 0, *Result.SourceManager,
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Result.Context->getLangOpts()),
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Replacement);
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}
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} // namespace misc
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} // namespace tidy
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} // namespace clang
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