clang-tools 17.0.0git
CalleeNamespaceCheck.cpp
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1//===-- CalleeNamespaceCheck.cpp ------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
10#include "clang/AST/ASTContext.h"
11#include "clang/ASTMatchers/ASTMatchFinder.h"
12
13#include "llvm/ADT/StringSet.h"
14
15using namespace clang::ast_matchers;
16
18
19// Gets the outermost namespace of a DeclContext, right under the Translation
20// Unit.
21const DeclContext *getOutermostNamespace(const DeclContext *Decl) {
22 const DeclContext *Parent = Decl->getParent();
23 if (Parent->isTranslationUnit())
24 return Decl;
26}
27
28void CalleeNamespaceCheck::registerMatchers(MatchFinder *Finder) {
29 Finder->addMatcher(
30 declRefExpr(to(functionDecl().bind("func"))).bind("use-site"), this);
31}
32
33// A list of functions that are exempted from this check. The __errno_location
34// function is for setting errno, which is allowed in libc, and the other
35// functions are specifically allowed to be external so that they can be
36// intercepted.
37static const llvm::StringSet<> IgnoredFunctions = {
38 "__errno_location", "malloc", "calloc", "realloc", "free", "aligned_alloc"};
39
40void CalleeNamespaceCheck::check(const MatchFinder::MatchResult &Result) {
41 const auto *UsageSiteExpr = Result.Nodes.getNodeAs<DeclRefExpr>("use-site");
42 const auto *FuncDecl = Result.Nodes.getNodeAs<FunctionDecl>("func");
43
44 // Ignore compiler builtin functions.
45 if (FuncDecl->getBuiltinID() != 0)
46 return;
47
48 // If the outermost namespace of the function is __llvm_libc, we're good.
49 const auto *NS = dyn_cast<NamespaceDecl>(getOutermostNamespace(FuncDecl));
50 if (NS && NS->getName() == "__llvm_libc")
51 return;
52
53 const DeclarationName &Name = FuncDecl->getDeclName();
54 if (Name.isIdentifier() &&
55 IgnoredFunctions.contains(Name.getAsIdentifierInfo()->getName()))
56 return;
57
58 diag(UsageSiteExpr->getBeginLoc(), "%0 must resolve to a function declared "
59 "within the '__llvm_libc' namespace")
60 << FuncDecl;
61
62 diag(FuncDecl->getLocation(), "resolves to this declaration",
63 clang::DiagnosticIDs::Note);
64}
65
66} // namespace clang::tidy::llvm_libc
const FunctionDecl * Decl
const Node * Parent
Token Name
DiagnosticBuilder diag(SourceLocation Loc, StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning)
Add a diagnostic with the check's name.
void check(const ast_matchers::MatchFinder::MatchResult &Result) override
ClangTidyChecks that register ASTMatchers should do the actual work in here.
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.
const DeclContext * getOutermostNamespace(const DeclContext *Decl)
static const llvm::StringSet IgnoredFunctions