1 //===-- InlineFunctionDeclCheck.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
9 #include "InlineFunctionDeclCheck.h"
10 #include "../utils/FileExtensionsUtils.h"
11 #include "../utils/LexerUtils.h"
12 #include "clang/AST/ASTContext.h"
13 #include "clang/ASTMatchers/ASTMatchFinder.h"
14
15 #include "llvm/ADT/StringSet.h"
16
17 using namespace clang::ast_matchers;
18
19 namespace clang::tidy::llvm_libc {
20
21 namespace {
22
23 const TemplateParameterList *
getLastTemplateParameterList(const FunctionDecl * FuncDecl)24 getLastTemplateParameterList(const FunctionDecl *FuncDecl) {
25 const TemplateParameterList *ReturnList =
26 FuncDecl->getDescribedTemplateParams();
27
28 if (!ReturnList) {
29 const unsigned NumberOfTemplateParameterLists =
30 FuncDecl->getNumTemplateParameterLists();
31
32 if (NumberOfTemplateParameterLists > 0)
33 ReturnList = FuncDecl->getTemplateParameterList(
34 NumberOfTemplateParameterLists - 1);
35 }
36
37 return ReturnList;
38 }
39
40 } // namespace
41
InlineFunctionDeclCheck(StringRef Name,ClangTidyContext * Context)42 InlineFunctionDeclCheck::InlineFunctionDeclCheck(StringRef Name,
43 ClangTidyContext *Context)
44 : ClangTidyCheck(Name, Context),
45 HeaderFileExtensions(Context->getHeaderFileExtensions()) {}
46
registerMatchers(MatchFinder * Finder)47 void InlineFunctionDeclCheck::registerMatchers(MatchFinder *Finder) {
48 // Ignore functions that have been deleted.
49 Finder->addMatcher(decl(functionDecl(unless(isDeleted()))).bind("func_decl"),
50 this);
51 }
52
check(const MatchFinder::MatchResult & Result)53 void InlineFunctionDeclCheck::check(const MatchFinder::MatchResult &Result) {
54 const auto *FuncDecl = Result.Nodes.getNodeAs<FunctionDecl>("func_decl");
55
56 // Consider only explicitly or implicitly inline functions.
57 if (FuncDecl == nullptr || !FuncDecl->isInlined())
58 return;
59
60 SourceLocation SrcBegin = FuncDecl->getBeginLoc();
61
62 // If we have a template parameter list, we need to skip that because the
63 // LIBC_INLINE macro must be placed after that.
64 if (const TemplateParameterList *TemplateParams =
65 getLastTemplateParameterList(FuncDecl)) {
66 SrcBegin = TemplateParams->getRAngleLoc();
67 std::optional<Token> NextToken =
68 utils::lexer::findNextTokenSkippingComments(
69 SrcBegin, *Result.SourceManager, Result.Context->getLangOpts());
70 if (NextToken)
71 SrcBegin = NextToken->getLocation();
72 }
73
74 // Consider functions only in header files.
75 if (!utils::isSpellingLocInHeaderFile(SrcBegin, *Result.SourceManager,
76 HeaderFileExtensions))
77 return;
78
79 // Ignore lambda functions as they are internal and implicit.
80 if (const auto *MethodDecl = dyn_cast<CXXMethodDecl>(FuncDecl))
81 if (MethodDecl->getParent()->isLambda())
82 return;
83
84 // Check if decl starts with LIBC_INLINE
85 auto Loc = FullSourceLoc(Result.SourceManager->getFileLoc(SrcBegin),
86 *Result.SourceManager);
87 llvm::StringRef SrcText = Loc.getBufferData().drop_front(Loc.getFileOffset());
88 if (SrcText.starts_with("LIBC_INLINE"))
89 return;
90
91 diag(SrcBegin, "%0 must be tagged with the LIBC_INLINE macro; the macro "
92 "should be placed at the beginning of the declaration")
93 << FuncDecl << FixItHint::CreateInsertion(Loc, "LIBC_INLINE ");
94 }
95
96 } // namespace clang::tidy::llvm_libc
97