clang-tools 10.0.0

RedundantPreprocessorCheck.cpp
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1 //===--- RedundantPreprocessorCheck.cpp - clang-tidy ----------------------===//
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 "RedundantPreprocessorCheck.h"
10 #include "clang/Frontend/CompilerInstance.h"
11
12 namespace clang {
13 namespace tidy {
14 namespace readability {
15
16 namespace {
17 /// Information about an opening preprocessor directive.
18 struct PreprocessorEntry {
19 SourceLocation Loc;
20 /// Condition used after the preprocessor directive.
21 std::string Condition;
22 };
23
24 class RedundantPreprocessorCallbacks : public PPCallbacks {
25 enum DirectiveKind { DK_If = 0, DK_Ifdef = 1, DK_Ifndef = 2 };
26
27 public:
28 explicit RedundantPreprocessorCallbacks(ClangTidyCheck &Check,
29 Preprocessor &PP)
30 : Check(Check), PP(PP),
31 WarningDescription("nested redundant %select{#if|#ifdef|#ifndef}0; "
32 "consider removing it"),
33 NoteDescription("previous %select{#if|#ifdef|#ifndef}0 was here") {}
34
35 void If(SourceLocation Loc, SourceRange ConditionRange,
36 ConditionValueKind ConditionValue) override {
37 StringRef Condition =
38 Lexer::getSourceText(CharSourceRange::getTokenRange(ConditionRange),
39 PP.getSourceManager(), PP.getLangOpts());
40 CheckMacroRedundancy(Loc, Condition, IfStack, DK_If, DK_If, true);
41 }
42
43 void Ifdef(SourceLocation Loc, const Token &MacroNameTok,
44 const MacroDefinition &MacroDefinition) override {
45 std::string MacroName = PP.getSpelling(MacroNameTok);
46 CheckMacroRedundancy(Loc, MacroName, IfdefStack, DK_Ifdef, DK_Ifdef, true);
47 CheckMacroRedundancy(Loc, MacroName, IfndefStack, DK_Ifdef, DK_Ifndef,
48 false);
49 }
50
51 void Ifndef(SourceLocation Loc, const Token &MacroNameTok,
52 const MacroDefinition &MacroDefinition) override {
53 std::string MacroName = PP.getSpelling(MacroNameTok);
54 CheckMacroRedundancy(Loc, MacroName, IfndefStack, DK_Ifndef, DK_Ifndef,
55 true);
56 CheckMacroRedundancy(Loc, MacroName, IfdefStack, DK_Ifndef, DK_Ifdef,
57 false);
58 }
59
60 void Endif(SourceLocation Loc, SourceLocation IfLoc) override {
61 if (!IfStack.empty() && IfLoc == IfStack.back().Loc)
62 IfStack.pop_back();
63 if (!IfdefStack.empty() && IfLoc == IfdefStack.back().Loc)
64 IfdefStack.pop_back();
65 if (!IfndefStack.empty() && IfLoc == IfndefStack.back().Loc)
66 IfndefStack.pop_back();
67 }
68
69 private:
70 void CheckMacroRedundancy(SourceLocation Loc, StringRef MacroName,
71 SmallVector<PreprocessorEntry, 4> &Stack,
72 DirectiveKind WarningKind, DirectiveKind NoteKind,
73 bool Store) {
74 if (PP.getSourceManager().isInMainFile(Loc)) {
75 for (const auto &Entry : Stack) {
76 if (Entry.Condition == MacroName) {
77 Check.diag(Loc, WarningDescription) << WarningKind;
78 Check.diag(Entry.Loc, NoteDescription, DiagnosticIDs::Note)
79 << NoteKind;
80 }
81 }
82 }
83
84 if (Store)
85 // This is an actual directive to be remembered.
86 Stack.push_back({Loc, MacroName});
87 }
88
89 ClangTidyCheck &Check;
90 Preprocessor &PP;
91 SmallVector<PreprocessorEntry, 4> IfStack;
92 SmallVector<PreprocessorEntry, 4> IfdefStack;
93 SmallVector<PreprocessorEntry, 4> IfndefStack;
94 const std::string WarningDescription;
95 const std::string NoteDescription;
96 };
97 } // namespace
98
99 void RedundantPreprocessorCheck::registerPPCallbacks(
100 const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) {
101 PP->addPPCallbacks(
102 ::std::make_unique<RedundantPreprocessorCallbacks>(*this, *PP));
103 }
104
105 } // namespace readability
106 } // namespace tidy
107 } // namespace clang
Loc
SourceLocation Loc
Definition: RedundantPreprocessorCheck.cpp:19
DirectiveKind
clang::tok::PPKeywordKind DirectiveKind
Definition: PreprocessorTracker.cpp:720
Entry::Loc
Location Loc
Definition: Modularize.cpp:438
clang::clangd::getTokenRange
llvm::Optional< Range > getTokenRange(const SourceManager &SM, const LangOptions &LangOpts, SourceLocation TokLoc)
Returns the taken range at TokLoc.
Definition: SourceCode.cpp:227
PPCallbacks
ConditionValue
clang::PPCallbacks::ConditionValueKind ConditionValue
Definition: PreprocessorTracker.cpp:672
clang::tidy::readability::RedundantPreprocessorCheck::registerPPCallbacks
void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) override
Override this to register PPCallbacks in the preprocessor.
Definition: RedundantPreprocessorCheck.cpp:99
clang
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Definition: ApplyReplacements.h:27
Condition
std::string Condition
Condition used after the preprocessor directive.
Definition: RedundantPreprocessorCheck.cpp:21
Entry
Definition: Modularize.cpp:429
RedundantPreprocessorCheck.h