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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "TempRefPtrChecker.h"
#include "CustomMatchers.h"
constexpr const char *kCallExpr = "call-expr";
constexpr const char *kOperatorCallExpr = "operator-call";
void TempRefPtrChecker::registerMatchers(MatchFinder *AstMatcher) {
AstMatcher->addMatcher(
cxxOperatorCallExpr(
hasOverloadedOperatorName("->"),
hasAnyArgument(implicitCastExpr(
hasSourceExpression(materializeTemporaryExpr(anyOf(
hasDescendant(callExpr().bind(kCallExpr)), anything()))))),
callee(hasDeclContext(classTemplateSpecializationDecl(
isSmartPtrToRefCountedDecl(),
// ignore any calls on temporary RefPtr<MozPromise<T>>,
// since these typically need to be locally ref-counted,
// e.g. in Then chains where the promise might be resolved
// concurrently
unless(hasTemplateArgument(
0, refersToType(hasDeclaration(
cxxRecordDecl(hasName("mozilla::MozPromise"))))))))))
.bind(kOperatorCallExpr),
this);
}
void TempRefPtrChecker::check(const MatchFinder::MatchResult &Result) {
const auto *OCE =
Result.Nodes.getNodeAs<CXXOperatorCallExpr>(kOperatorCallExpr);
const auto *refPtrDecl =
dyn_cast<const CXXRecordDecl>(OCE->getCalleeDecl()->getDeclContext());
diag(OCE->getOperatorLoc(),
"performance issue: temporary %0 is only dereferenced here once which "
"involves short-lived AddRef/Release calls")
<< refPtrDecl;
const auto *InnerCE = Result.Nodes.getNodeAs<CallExpr>(kCallExpr);
if (InnerCE) {
const auto functionName =
InnerCE->getCalleeDecl()->getAsFunction()->getQualifiedNameAsString();
if (functionName != "mozilla::MakeRefPtr") {
diag(
OCE->getOperatorLoc(),
"consider changing function %0 to return a raw reference instead (be "
"sure that the pointee is held alive by someone else though!)",
DiagnosticIDs::Note)
<< functionName;
}
}
}
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