78 lines
3.0 KiB
C++
78 lines
3.0 KiB
C++
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "IntToEnumCastChecker.h"
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#include "CustomMatchers.h"
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void IntToEnumCastChecker::registerMatchers(MatchFinder *AstMatcher) {
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// Match any explicit cast from a builtin type to an enum type, inside
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// methods of IPC actor classes (those deriving from mozilla::ipc::IProtocol).
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// This covers static_cast, C-style casts, and functional casts.
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//
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// We anchor on the method and descend into its whole body with
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// forEachDescendant, rather than using forCallable on the cast itself:
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// forCallable only matches the immediately enclosing callable, so casts
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// inside a lambda (which IPC code uses heavily for promises) would have the
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// lambda's operator() as their callable and be missed.
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AstMatcher->addMatcher(
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cxxMethodDecl(
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ofClass(isDerivedFrom(hasName("mozilla::ipc::IProtocol"))),
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isFirstParty(),
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forEachDescendant(
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explicitCastExpr(
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hasDestinationType(qualType(hasCanonicalType(enumType()))),
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hasSourceExpression(expr(
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hasType(qualType(hasCanonicalType(builtinType()))))))
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.bind("cast"))),
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this);
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}
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void IntToEnumCastChecker::check(const MatchFinder::MatchResult &Result) {
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const ExplicitCastExpr *Cast =
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Result.Nodes.getNodeAs<ExplicitCastExpr>("cast");
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// Skip casts in gtest code, which exercises IPC actors with synthetic values
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// and would otherwise be flagged by this checker.
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StringRef FileName =
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getFilename(Result.Context->getSourceManager(), Cast->getBeginLoc());
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for (auto Begin = llvm::sys::path::rbegin(FileName),
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End = llvm::sys::path::rend(FileName);
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Begin != End; ++Begin) {
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if (*Begin == "gtest") {
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return;
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}
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}
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// Compiler-inserted casts (e.g. from non-type template parameter
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// substitution) share the same source range as their sub-expression,
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// since no cast syntax was written. Skip those.
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const Expr *Sub = Cast->getSubExpr()->IgnoreImpCasts();
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if (Cast->getBeginLoc() == Sub->getBeginLoc() &&
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Cast->getEndLoc() == Sub->getEndLoc()) {
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return;
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}
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QualType DestType = Cast->getTypeAsWritten();
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QualType SrcType = Cast->getSubExpr()->getType();
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const char *CastName = "cast";
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if (isa<CXXStaticCastExpr>(Cast)) {
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CastName = "static_cast";
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} else if (isa<CXXFunctionalCastExpr>(Cast)) {
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CastName = "functional cast";
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} else if (isa<CStyleCastExpr>(Cast)) {
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CastName = "C-style cast";
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}
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diag(Cast->getBeginLoc(),
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"%2 from builtin type %0 to enum type %1 in an IPC actor method may "
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"produce an out-of-range enum value",
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DiagnosticIDs::Error)
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<< SrcType << DestType << CastName;
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diag(Cast->getBeginLoc(),
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"consider using the enum type directly in the IPDL definition with a "
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"validated EnumSerializer, or use a clamping function",
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DiagnosticIDs::Note);
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}
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