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Lagom: Enforce uniform calls to Base::visit_edges in LibJSGCVerifier

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This ensures that all visit_edges implementations include a call to
Base::visit_edges. In particular, this gives three nice benefits:

  - The call can't be forgotten (the main benefit, of course).
  - All of the calls look the same. In other words, always use "Base"
    instead of the actual concrete class.
  - Ensure the object has a call to JS_CELL or JS_OBJECT in the
    definition. Otherwise, Base will not be defined and the call will
    not compile.
This commit is contained in:
Matthew Olsson 2023-03-20 13:34:36 -07:00 • committed by Andreas Kling
parent 3f22919eb5
commit 98ed74087f
Notes: sideshowbarker 2024-07-17 16:23:06 +09:00
1 changed files with 61 additions and 4 deletions
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65
Meta/Lagom/Tools/LibJSGCVerifier/src/CellsHandler.cpp
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@ -18,6 +18,27 @@
#include <unordered_set>
#include <vector>
template<typename T>
class SimpleCollectMatchesCallback : public clang::ast_matchers::MatchFinder::MatchCallback {
public:
explicit SimpleCollectMatchesCallback(std::string name)
: m_name(std::move(name))
{
}
void run(clang::ast_matchers::MatchFinder::MatchResult const& result) override
{
if (auto const* node = result.Nodes.getNodeAs<T>(m_name))
m_matches.push_back(node);
}
auto const& matches() const { return m_matches; }
private:
std::string m_name;
std::vector<T const*> m_matches;
};
CollectCellsHandler::CollectCellsHandler()
{
using namespace clang::ast_matchers;
@ -32,7 +53,6 @@ CollectCellsHandler::CollectCellsHandler()
bool CollectCellsHandler::handleBeginSource(clang::CompilerInstance& ci)
{
auto const& source_manager = ci.getSourceManager();
ci.getFileManager().getNumUniqueRealFiles();
auto file_id = source_manager.getMainFileID();
auto const* file_entry = source_manager.getFileEntryForID(file_id);
if (!file_entry)
@ -142,6 +162,8 @@ FieldValidationResult validate_field(clang::FieldDecl const* field_decl)
void CollectCellsHandler::run(clang::ast_matchers::MatchFinder::MatchResult const& result)
{
using namespace clang::ast_matchers;
clang::CXXRecordDecl const* record = result.Nodes.getNodeAs<clang::CXXRecordDecl>("record-decl");
if (!record || !record->isCompleteDefinition() || (!record->isClass() && !record->isStruct()))
return;
@ -149,8 +171,6 @@ void CollectCellsHandler::run(clang::ast_matchers::MatchFinder::MatchResult cons
auto& diag_engine = result.Context->getDiagnostics();
for (clang::FieldDecl const* field : record->fields()) {
auto const& type = field->getType();
auto validation_results = validate_field(field);
if (!validation_results.is_valid) {
if (validation_results.is_wrapped_in_gcptr) {
@ -159,7 +179,7 @@ void CollectCellsHandler::run(clang::ast_matchers::MatchFinder::MatchResult cons
} else {
auto diag_id = diag_engine.getCustomDiagID(clang::DiagnosticsEngine::Warning, "%0 to JS::Cell type should be wrapped in %1");
auto builder = diag_engine.Report(field->getLocation(), diag_id);
if (type->isReferenceType()) {
if (field->getType()->isReferenceType()) {
builder << "reference"
<< "JS::NonnullGCPtr";
} else {
@ -169,4 +189,41 @@ void CollectCellsHandler::run(clang::ast_matchers::MatchFinder::MatchResult cons
}
}
}
if (!record_inherits_from_cell(*record))
return;
clang::DeclarationName const name = &result.Context->Idents.get("visit_edges");
auto const* visit_edges_method = record->lookup(name).find_first<clang::CXXMethodDecl>();
if (!visit_edges_method || !visit_edges_method->getBody())
return;
// Search for a call to Base::visit_edges. Note that this also has the nice side effect of
// ensuring the classes use JS_CELL/JS_OBJECT, as Base will not be defined if they do not.
MatchFinder base_visit_edges_finder;
SimpleCollectMatchesCallback<clang::CXXMemberCallExpr> base_visit_edges_callback("member-call");
auto base_visit_edges_matcher = cxxMemberCallExpr(
callee(memberExpr(member(hasName("visit_edges")))))
.bind("member-call");
base_visit_edges_finder.addMatcher(base_visit_edges_matcher, &base_visit_edges_callback);
base_visit_edges_finder.matchAST(*result.Context);
bool call_to_base_visit_edges_found = false;
for (auto const* call_expr : base_visit_edges_callback.matches()) {
// FIXME: Can we constrain the matcher above to avoid looking directly at the source code?
auto const* source_chars = result.SourceManager->getCharacterData(call_expr->getBeginLoc());
if (strncmp(source_chars, "Base::", 6) == 0) {
call_to_base_visit_edges_found = true;
break;
}
}
if (!call_to_base_visit_edges_found) {
auto diag_id = diag_engine.getCustomDiagID(clang::DiagnosticsEngine::Warning, "Missing call to Base::visit_edges");
diag_engine.Report(visit_edges_method->getBeginLoc(), diag_id);
}
}