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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
* file, You can obtain one at */
#include "CustomAttributes.h"
#include "plugin.h"
#include "clang/Frontend/FrontendPluginRegistry.h"
#include <algorithm>
/* Having annotations in the AST unexpectedly impacts codegen.
* Ideally, we'd avoid having annotations at all, by using an API such as
* the one from, and storing the attributes
* data separately from the AST on our own. Unfortunately, there is no such
* API currently in clang, so we must do without.
* We can do something similar, though, where we go through the AST before
* running the checks, create a mapping of AST nodes to attributes, and
* remove the attributes/annotations from the AST nodes.
* Not all declarations can be reached from the decl() AST matcher, though,
* so we do our best effort (getting the other declarations we look at in
* checks). We emit a warning when checks look at a note that still has
* annotations attached (aka, hasn't been seen during our first pass),
* so that those don't go unnoticed. (-Werror should then take care of
* making that an error)
using namespace clang;
using namespace llvm;
static DenseMap<const Decl *, CustomAttributesSet> AttributesCache;
static CustomAttributesSet CacheAttributes(const Decl *D) {
CustomAttributesSet attrs = {};
for (auto Attr : D->specific_attrs<AnnotateAttr>()) {
auto annotation = Attr->getAnnotation();
#define ATTR(a) \
if (annotation == #a) { \
attrs.has_##a = true; \
} else
#include ""
#include "external/"
#undef ATTR
const_cast<Decl *>(D)->dropAttr<AnnotateAttr>();
AttributesCache.insert(std::make_pair(D, attrs));
return attrs;
#ifndef CLANG_TIDY
static void Report(const Decl *D, const char *message) {
ASTContext &Context = D->getASTContext();
DiagnosticsEngine &Diag = Context.getDiagnostics();
unsigned ID =
Diag.getDiagnosticIDs()->getCustomDiagID(DiagnosticIDs::Warning, message);
Diag.Report(D->getBeginLoc(), ID);
class CustomAttributesMatcher
: public ast_matchers::MatchFinder::MatchCallback {
void run(const ast_matchers::MatchFinder::MatchResult &Result) final {
if (auto D = Result.Nodes.getNodeAs<Decl>("decl")) {
} else if (auto L = Result.Nodes.getNodeAs<LambdaExpr>("lambda")) {
class CustomAttributesAction : public PluginASTAction {
ASTConsumerPtr CreateASTConsumer(CompilerInstance &CI,
StringRef FileName) override {
auto &Context = CI.getASTContext();
auto AstMatcher = new (Context.Allocate<MatchFinder>()) MatchFinder();
auto Matcher = new (Context.Allocate<CustomAttributesMatcher>())
AstMatcher->addMatcher(decl().bind("decl"), Matcher);
AstMatcher->addMatcher(lambdaExpr().bind("lambda"), Matcher);
return AstMatcher->newASTConsumer();
bool ParseArgs(const CompilerInstance &CI,
const std::vector<std::string> &Args) override {
return true;
ActionType getActionType() override { return AddBeforeMainAction; }
static FrontendPluginRegistry::Add<CustomAttributesAction>
X("moz-custom-attributes", "prepare custom attributes for moz-check");
CustomAttributesSet GetAttributes(const Decl *D) {
CustomAttributesSet attrs = {};
if (D->hasAttr<AnnotateAttr>()) {
// If we are not in clang-tidy env push warnings, most likely we are in the
// build environment and this should have been done in AstMatcher -
// CustomAttributesMatcher
#ifndef CLANG_TIDY
Report(D, "Declaration has unhandled annotations.");
attrs = CacheAttributes(D);
} else {
auto attributes = AttributesCache.find(D);
if (attributes != AttributesCache.end()) {
attrs = attributes->second;
return attrs;
bool hasCustomAttribute(const clang::Decl *D, CustomAttributes A) {
CustomAttributesSet attrs = GetAttributes(D);
switch (A) {
#define ATTR(a) \
case a: \
return attrs.has_##a;
#include ""
#include "external/"
#undef ATTR
return false;