forked from mirrors/gecko-dev
0d4a611a04
MozReview-Commit-ID: AXrQEjWzxvg --HG-- extra : rebase_source : bf972fbb22648af2edbb756eb899ebddf8444dbc
99 lines
3.7 KiB
C++
99 lines
3.7 KiB
C++
/* 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 "KungFuDeathGripChecker.h"
|
|
#include "CustomMatchers.h"
|
|
|
|
void KungFuDeathGripChecker::registerMatchers(MatchFinder *AstMatcher) {
|
|
AstMatcher->addMatcher(varDecl(hasType(isRefPtr())).bind("decl"), this);
|
|
}
|
|
|
|
void KungFuDeathGripChecker::check(const MatchFinder::MatchResult &Result) {
|
|
const char *Error = "Unused \"kungFuDeathGrip\" %0 objects constructed from "
|
|
"%1 are prohibited";
|
|
const char *Note = "Please switch all accesses to this %0 to go through "
|
|
"'%1', or explicitly pass '%1' to `mozilla::Unused`";
|
|
|
|
const VarDecl *D = Result.Nodes.getNodeAs<VarDecl>("decl");
|
|
if (D->isReferenced() || !D->hasLocalStorage() || !D->hasInit()) {
|
|
return;
|
|
}
|
|
|
|
// Not interested in parameters.
|
|
if (isa<ImplicitParamDecl>(D) || isa<ParmVarDecl>(D)) {
|
|
return;
|
|
}
|
|
|
|
const Expr *E = IgnoreTrivials(D->getInit());
|
|
const CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(E);
|
|
if (CE && CE->getNumArgs() == 0) {
|
|
// We don't report an error when we construct and don't use a nsCOMPtr /
|
|
// nsRefPtr with no arguments. We don't report it because the error is not
|
|
// related to the current check. In the future it may be reported through a
|
|
// more generic mechanism.
|
|
return;
|
|
}
|
|
|
|
// We don't want to look at the single argument conversion constructors
|
|
// which are inbetween the declaration and the actual object which we are
|
|
// assigning into the nsCOMPtr/RefPtr. To do this, we repeatedly
|
|
// IgnoreTrivials, then look at the expression. If it is one of these
|
|
// conversion constructors, we ignore it and continue to dig.
|
|
while ((CE = dyn_cast<CXXConstructExpr>(E)) && CE->getNumArgs() == 1) {
|
|
E = IgnoreTrivials(CE->getArg(0));
|
|
}
|
|
|
|
// We allow taking a kungFuDeathGrip of `this` because it cannot change
|
|
// beneath us, so calling directly through `this` is OK. This is the same
|
|
// for local variable declarations.
|
|
//
|
|
// We also don't complain about unused RefPtrs which are constructed from
|
|
// the return value of a new expression, as these are required in order to
|
|
// immediately destroy the value created (which was presumably created for
|
|
// its side effects), and are not used as a death grip.
|
|
if (isa<CXXThisExpr>(E) || isa<DeclRefExpr>(E) || isa<CXXNewExpr>(E)) {
|
|
return;
|
|
}
|
|
|
|
// These types are assigned into nsCOMPtr and RefPtr for their side effects,
|
|
// and not as a kungFuDeathGrip. We don't want to consider RefPtr and nsCOMPtr
|
|
// types which are initialized with these types as errors.
|
|
const TagDecl *TD = E->getType()->getAsTagDecl();
|
|
if (TD && TD->getIdentifier()) {
|
|
static const char *IgnoreTypes[] = {
|
|
"already_AddRefed",
|
|
"nsGetServiceByCID",
|
|
"nsGetServiceByCIDWithError",
|
|
"nsGetServiceByContractID",
|
|
"nsGetServiceByContractIDWithError",
|
|
"nsCreateInstanceByCID",
|
|
"nsCreateInstanceByContractID",
|
|
"nsCreateInstanceFromFactory",
|
|
};
|
|
|
|
for (uint32_t i = 0; i < sizeof(IgnoreTypes) / sizeof(IgnoreTypes[0]);
|
|
++i) {
|
|
if (TD->getName() == IgnoreTypes[i]) {
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Report the error
|
|
const char *ErrThing;
|
|
const char *NoteThing;
|
|
if (isa<MemberExpr>(E)) {
|
|
ErrThing = "members";
|
|
NoteThing = "member";
|
|
} else {
|
|
ErrThing = "temporary values";
|
|
NoteThing = "value";
|
|
}
|
|
|
|
// We cannot provide the note if we don't have an initializer
|
|
diag(D->getLocStart(), Error, DiagnosticIDs::Error)
|
|
<< D->getType() << ErrThing;
|
|
diag(E->getLocStart(), Note, DiagnosticIDs::Note)
|
|
<< NoteThing << getNameChecked(D);
|
|
}
|