| 1 | //===-- CalleeNamespaceCheck.cpp ------------------------------------------===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | |
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| 9 | #include "CalleeNamespaceCheck.h" |
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| 10 | #include "NamespaceConstants.h" |
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| 11 | #include "clang/AST/ASTContext.h" |
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| 12 | #include "clang/ASTMatchers/ASTMatchFinder.h" |
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| 13 | |
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| 14 | #include "clang/ASTMatchers/ASTMatchers.h" |
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| 15 | #include "llvm/ADT/StringSet.h" |
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| 16 | |
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| 17 | using namespace clang::ast_matchers; |
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| 18 | |
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| 19 | namespace clang::tidy::llvm_libc { |
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| 20 | |
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| 21 | // Gets the outermost namespace of a DeclContext, right under the Translation |
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| 22 | // Unit. |
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| 23 | const DeclContext *getOutermostNamespace(const DeclContext *Decl) { |
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| 24 | const DeclContext *Parent = Decl->getParent(); |
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| 25 | if (Parent->isTranslationUnit()) |
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| 26 | return Decl; |
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| 27 | return getOutermostNamespace(Decl: Parent); |
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| 28 | } |
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| 29 | |
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| 30 | void CalleeNamespaceCheck::registerMatchers(MatchFinder *Finder) { |
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| 31 | Finder->addMatcher( |
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| 32 | NodeMatch: declRefExpr(to(InnerMatcher: functionDecl().bind(ID: "func" ))).bind(ID: "use-site" ), Action: this); |
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| 33 | } |
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| 34 | |
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| 35 | // A list of functions that are exempted from this check. The __errno_location |
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| 36 | // function is for setting errno, which is allowed in libc, and the other |
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| 37 | // functions are specifically allowed to be external so that they can be |
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| 38 | // intercepted. |
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| 39 | static const llvm::StringSet<> IgnoredFunctions = { |
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| 40 | "__errno_location" , "malloc" , "calloc" , "realloc" , "free" , "aligned_alloc" }; |
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| 41 | |
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| 42 | void CalleeNamespaceCheck::check(const MatchFinder::MatchResult &Result) { |
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| 43 | const auto *UsageSiteExpr = Result.Nodes.getNodeAs<DeclRefExpr>(ID: "use-site" ); |
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| 44 | const auto *FuncDecl = Result.Nodes.getNodeAs<FunctionDecl>(ID: "func" ); |
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| 45 | |
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| 46 | // Ignore compiler builtin functions. |
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| 47 | if (FuncDecl->getBuiltinID() != 0) |
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| 48 | return; |
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| 49 | |
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| 50 | // If the outermost namespace of the function is a macro that starts with |
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| 51 | // __llvm_libc, we're good. |
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| 52 | const auto *NS = dyn_cast<NamespaceDecl>(Val: getOutermostNamespace(FuncDecl)); |
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| 53 | if (NS && Result.SourceManager->isMacroBodyExpansion(Loc: NS->getLocation()) && |
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| 54 | NS->getName().starts_with(RequiredNamespaceStart)) |
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| 55 | return; |
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| 56 | |
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| 57 | const DeclarationName &Name = FuncDecl->getDeclName(); |
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| 58 | if (Name.isIdentifier() && |
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| 59 | IgnoredFunctions.contains(key: Name.getAsIdentifierInfo()->getName())) |
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| 60 | return; |
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| 61 | |
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| 62 | diag(Loc: UsageSiteExpr->getBeginLoc(), |
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| 63 | Description: "%0 must resolve to a function declared " |
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| 64 | "within the namespace defined by the '%1' macro" ) |
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| 65 | << FuncDecl << RequiredNamespaceMacroName; |
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| 66 | |
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| 67 | diag(FuncDecl->getLocation(), "resolves to this declaration" , |
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| 68 | clang::DiagnosticIDs::Note); |
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| 69 | } |
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| 70 | |
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| 71 | } // namespace clang::tidy::llvm_libc |
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| 72 | |
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