void FindBadConstructsConsumer::CheckCtorDtorWeight(
SourceLocation record_location,
CXXRecordDecl* record) {
// We don't handle anonymous structs. If this record doesn't have a
// name, it's of the form:
//
// struct {
// ...
// } name_;
if (record->getIdentifier() == NULL)
return;
// Count the number of templated base classes as a feature of whether the
// destructor can be inlined.
int templated_base_classes = 0;
for (CXXRecordDecl::base_class_const_iterator it = record->bases_begin();
it != record->bases_end();
++it) {
if (it->getTypeSourceInfo()->getTypeLoc().getTypeLocClass() ==
TypeLoc::TemplateSpecialization) {
++templated_base_classes;
}
}
// Count the number of trivial and non-trivial member variables.
int trivial_member = 0;
int non_trivial_member = 0;
int templated_non_trivial_member = 0;
for (RecordDecl::field_iterator it = record->field_begin();
it != record->field_end();
++it) {
CountType(it->getType().getTypePtr(),
&trivial_member,
&non_trivial_member,
&templated_non_trivial_member);
}
// Check to see if we need to ban inlined/synthesized constructors. Note
// that the cutoffs here are kind of arbitrary. Scores over 10 break.
int dtor_score = 0;
// Deriving from a templated base class shouldn't be enough to trigger
// the ctor warning, but if you do *anything* else, it should.
//
// TODO(erg): This is motivated by templated base classes that don't have
// any data members. Somehow detect when templated base classes have data
// members and treat them differently.
dtor_score += templated_base_classes * 9;
// Instantiating a template is an insta-hit.
dtor_score += templated_non_trivial_member * 10;
// The fourth normal class member should trigger the warning.
dtor_score += non_trivial_member * 3;
int ctor_score = dtor_score;
// You should be able to have 9 ints before we warn you.
ctor_score += trivial_member;
if (ctor_score >= 10) {
if (!record->hasUserDeclaredConstructor()) {
emitWarning(record_location,
"Complex class/struct needs an explicit out-of-line "
"constructor.");
} else {
// Iterate across all the constructors in this file and yell if we
// find one that tries to be inline.
for (CXXRecordDecl::ctor_iterator it = record->ctor_begin();
it != record->ctor_end();
++it) {
if (it->hasInlineBody()) {
if (it->isCopyConstructor() &&
!record->hasUserDeclaredCopyConstructor()) {
emitWarning(record_location,
"Complex class/struct needs an explicit out-of-line "
"copy constructor.");
} else {
emitWarning(it->getInnerLocStart(),
"Complex constructor has an inlined body.");
}
}
}
}
}
// The destructor side is equivalent except that we don't check for
// trivial members; 20 ints don't need a destructor.
if (dtor_score >= 10 && !record->hasTrivialDestructor()) {
if (!record->hasUserDeclaredDestructor()) {
emitWarning(record_location,
"Complex class/struct needs an explicit out-of-line "
"destructor.");
} else if (CXXDestructorDecl* dtor = record->getDestructor()) {
if (dtor->hasInlineBody()) {
emitWarning(dtor->getInnerLocStart(),
"Complex destructor has an inline body.");
}
}
}
}
