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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
#include "IntToEnumCastChecker.h"
#include "CustomMatchers.h"
void IntToEnumCastChecker::registerMatchers(MatchFinder *AstMatcher) {
// Match any explicit cast from a builtin type to an enum type, inside
// methods of IPC actor classes (those deriving from mozilla::ipc::IProtocol).
// This covers static_cast, C-style casts, and functional casts.
//
// We anchor on the method and descend into its whole body with
// forEachDescendant, rather than using forCallable on the cast itself:
// forCallable only matches the immediately enclosing callable, so casts
// inside a lambda (which IPC code uses heavily for promises) would have the
// lambda's operator() as their callable and be missed.
AstMatcher->addMatcher(
cxxMethodDecl(
ofClass(isDerivedFrom(hasName("mozilla::ipc::IProtocol"))),
isFirstParty(),
forEachDescendant(
explicitCastExpr(
hasDestinationType(qualType(hasCanonicalType(enumType()))),
hasSourceExpression(expr(
hasType(qualType(hasCanonicalType(builtinType()))))))
.bind("cast"))),
this);
}
void IntToEnumCastChecker::check(const MatchFinder::MatchResult &Result) {
const ExplicitCastExpr *Cast =
Result.Nodes.getNodeAs<ExplicitCastExpr>("cast");
// Skip casts in gtest code, which exercises IPC actors with synthetic values
// and would otherwise be flagged by this checker.
StringRef FileName =
getFilename(Result.Context->getSourceManager(), Cast->getBeginLoc());
for (auto Begin = llvm::sys::path::rbegin(FileName),
End = llvm::sys::path::rend(FileName);
Begin != End; ++Begin) {
if (*Begin == "gtest") {
return;
}
}
// Compiler-inserted casts (e.g. from non-type template parameter
// substitution) share the same source range as their sub-expression,
// since no cast syntax was written. Skip those.
const Expr *Sub = Cast->getSubExpr()->IgnoreImpCasts();
if (Cast->getBeginLoc() == Sub->getBeginLoc() &&
Cast->getEndLoc() == Sub->getEndLoc()) {
return;
}
QualType DestType = Cast->getTypeAsWritten();
QualType SrcType = Cast->getSubExpr()->getType();
const char *CastName = "cast";
if (isa<CXXStaticCastExpr>(Cast)) {
CastName = "static_cast";
} else if (isa<CXXFunctionalCastExpr>(Cast)) {
CastName = "functional cast";
} else if (isa<CStyleCastExpr>(Cast)) {
CastName = "C-style cast";
}
diag(Cast->getBeginLoc(),
"%2 from builtin type %0 to enum type %1 in an IPC actor method may "
"produce an out-of-range enum value",
DiagnosticIDs::Error)
<< SrcType << DestType << CastName;
diag(Cast->getBeginLoc(),
"consider using the enum type directly in the IPDL definition with a "
"validated EnumSerializer, or use a clamping function",
DiagnosticIDs::Note);
}