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//===-- CalleeNamespaceCheck.cpp ------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "CalleeNamespaceCheck.h"
#include "NamespaceConstants.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/ASTMatchers/ASTMatchers.h"
#include "llvm/ADT/StringSet.h"
using namespace clang::ast_matchers;
namespace clang::tidy::llvm_libc {
// Gets the outermost namespace of a DeclContext, right under the Translation
// Unit.
const DeclContext *getOutermostNamespace(const DeclContext *Decl) {
const DeclContext *Parent = Decl->getParent();
if (Parent->isTranslationUnit())
return Decl;
return getOutermostNamespace(Parent);
}
void CalleeNamespaceCheck::registerMatchers(MatchFinder *Finder) {
Finder->addMatcher(
declRefExpr(to(functionDecl().bind("func"))).bind("use-site"), this);
}
// A list of functions that are exempted from this check. The __errno_location
// function is for setting errno, which is allowed in libc, and the other
// functions are specifically allowed to be external so that they can be
// intercepted.
static const llvm::StringSet<> IgnoredFunctions = {
"__errno_location", "malloc", "calloc", "realloc", "free", "aligned_alloc"};
void CalleeNamespaceCheck::check(const MatchFinder::MatchResult &Result) {
const auto *UsageSiteExpr = Result.Nodes.getNodeAs<DeclRefExpr>("use-site");
const auto *FuncDecl = Result.Nodes.getNodeAs<FunctionDecl>("func");
// Ignore compiler builtin functions.
if (FuncDecl->getBuiltinID() != 0)
return;
// If the outermost namespace of the function is a macro that starts with
// __llvm_libc, we're good.
const auto *NS = dyn_cast<NamespaceDecl>(getOutermostNamespace(FuncDecl));
if (NS && Result.SourceManager->isMacroBodyExpansion(NS->getLocation()) &&
NS->getName().starts_with(RequiredNamespaceRefStart))
return;
const DeclarationName &Name = FuncDecl->getDeclName();
if (Name.isIdentifier() &&
IgnoredFunctions.contains(Name.getAsIdentifierInfo()->getName()))
return;
diag(UsageSiteExpr->getBeginLoc(),
"%0 must resolve to a function declared "
"within the namespace defined by the '%1' macro")
<< FuncDecl << RequiredNamespaceRefMacroName;
diag(FuncDecl->getLocation(), "resolves to this declaration",
clang::DiagnosticIDs::Note);
}
} // namespace clang::tidy::llvm_libc
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