clang-tools 6.0.0

FunctionSizeCheck.cpp
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1 //===--- FunctionSize.cpp - clang-tidy ------------------------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9
10 #include "FunctionSizeCheck.h"
11 #include "clang/AST/RecursiveASTVisitor.h"
12 #include "clang/ASTMatchers/ASTMatchFinder.h"
13
14 using namespace clang::ast_matchers;
15
16 namespace clang {
17 namespace tidy {
18 namespace readability {
19 namespace {
20
21 class FunctionASTVisitor : public RecursiveASTVisitor<FunctionASTVisitor> {
22 using Base = RecursiveASTVisitor<FunctionASTVisitor>;
23
24 public:
25 bool TraverseStmt(Stmt *Node) {
26 if (!Node)
27 return Base::TraverseStmt(Node);
28
29 if (TrackedParent.back() && !isa<CompoundStmt>(Node))
30 ++Info.Statements;
31
32 switch (Node->getStmtClass()) {
33 case Stmt::IfStmtClass:
34 case Stmt::WhileStmtClass:
35 case Stmt::DoStmtClass:
36 case Stmt::CXXForRangeStmtClass:
37 case Stmt::ForStmtClass:
38 case Stmt::SwitchStmtClass:
39 ++Info.Branches;
40 LLVM_FALLTHROUGH;
41 case Stmt::CompoundStmtClass:
42 TrackedParent.push_back(true);
43 break;
44 default:
45 TrackedParent.push_back(false);
46 break;
47 }
48
49 Base::TraverseStmt(Node);
50
51 TrackedParent.pop_back();
52
53 return true;
54 }
55
56 bool TraverseCompoundStmt(CompoundStmt *Node) {
57 // If this new compound statement is located in a compound statement, which
58 // is already nested NestingThreshold levels deep, record the start location
59 // of this new compound statement.
60 if (CurrentNestingLevel == Info.NestingThreshold)
61 Info.NestingThresholders.push_back(Node->getLocStart());
62
63 ++CurrentNestingLevel;
64 Base::TraverseCompoundStmt(Node);
65 --CurrentNestingLevel;
66
67 return true;
68 }
69
70 bool TraverseDecl(Decl *Node) {
71 TrackedParent.push_back(false);
72 Base::TraverseDecl(Node);
73 TrackedParent.pop_back();
74 return true;
75 }
76
77 struct FunctionInfo {
78 unsigned Lines = 0;
79 unsigned Statements = 0;
80 unsigned Branches = 0;
81 unsigned NestingThreshold = 0;
82 std::vector<SourceLocation> NestingThresholders;
83 };
84 FunctionInfo Info;
85 std::vector<bool> TrackedParent;
86 unsigned CurrentNestingLevel = 0;
87 };
88
89 } // namespace
90
91 FunctionSizeCheck::FunctionSizeCheck(StringRef Name, ClangTidyContext *Context)
92 : ClangTidyCheck(Name, Context),
93 LineThreshold(Options.get("LineThreshold", -1U)),
94 StatementThreshold(Options.get("StatementThreshold", 800U)),
95 BranchThreshold(Options.get("BranchThreshold", -1U)),
96 ParameterThreshold(Options.get("ParameterThreshold", -1U)),
97 NestingThreshold(Options.get("NestingThreshold", -1U)) {}
98
99 void FunctionSizeCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
100 Options.store(Opts, "LineThreshold", LineThreshold);
101 Options.store(Opts, "StatementThreshold", StatementThreshold);
102 Options.store(Opts, "BranchThreshold", BranchThreshold);
103 Options.store(Opts, "ParameterThreshold", ParameterThreshold);
104 Options.store(Opts, "NestingThreshold", NestingThreshold);
105 }
106
107 void FunctionSizeCheck::registerMatchers(MatchFinder *Finder) {
108 Finder->addMatcher(functionDecl(unless(isInstantiated())).bind("func"), this);
109 }
110
111 void FunctionSizeCheck::check(const MatchFinder::MatchResult &Result) {
112 const auto *Func = Result.Nodes.getNodeAs<FunctionDecl>("func");
113
114 FunctionASTVisitor Visitor;
115 Visitor.Info.NestingThreshold = NestingThreshold;
116 Visitor.TraverseDecl(const_cast<FunctionDecl *>(Func));
117 auto &FI = Visitor.Info;
118
119 if (FI.Statements == 0)
120 return;
121
122 // Count the lines including whitespace and comments. Really simple.
123 if (const Stmt *Body = Func->getBody()) {
124 SourceManager *SM = Result.SourceManager;
125 if (SM->isWrittenInSameFile(Body->getLocStart(), Body->getLocEnd())) {
126 FI.Lines = SM->getSpellingLineNumber(Body->getLocEnd()) -
127 SM->getSpellingLineNumber(Body->getLocStart());
128 }
129 }
130
131 unsigned ActualNumberParameters = Func->getNumParams();
132
133 if (FI.Lines > LineThreshold || FI.Statements > StatementThreshold ||
134 FI.Branches > BranchThreshold ||
135 ActualNumberParameters > ParameterThreshold ||
136 !FI.NestingThresholders.empty()) {
137 diag(Func->getLocation(),
138 "function %0 exceeds recommended size/complexity thresholds")
139 << Func;
140 }
141
142 if (FI.Lines > LineThreshold) {
143 diag(Func->getLocation(),
144 "%0 lines including whitespace and comments (threshold %1)",
145 DiagnosticIDs::Note)
146 << FI.Lines << LineThreshold;
147 }
148
149 if (FI.Statements > StatementThreshold) {
150 diag(Func->getLocation(), "%0 statements (threshold %1)",
151 DiagnosticIDs::Note)
152 << FI.Statements << StatementThreshold;
153 }
154
155 if (FI.Branches > BranchThreshold) {
156 diag(Func->getLocation(), "%0 branches (threshold %1)", DiagnosticIDs::Note)
157 << FI.Branches << BranchThreshold;
158 }
159
160 if (ActualNumberParameters > ParameterThreshold) {
161 diag(Func->getLocation(), "%0 parameters (threshold %1)",
162 DiagnosticIDs::Note)
163 << ActualNumberParameters << ParameterThreshold;
164 }
165
166 for (const auto &CSPos : FI.NestingThresholders) {
167 diag(CSPos, "nesting level %0 starts here (threshold %1)",
168 DiagnosticIDs::Note)
169 << NestingThreshold + 1 << NestingThreshold;
170 }
171 }
172
173 } // namespace readability
174 } // namespace tidy
175 } // namespace clang
clang::ast_matchers
Definition: ClangTidyDiagnosticConsumer.h:27
clang::tidy::OptionsView::store
void store(ClangTidyOptions::OptionMap &Options, StringRef LocalName, StringRef Value) const
Stores an option with the check-local name LocalName with string value Value to Options.
Definition: ClangTidy.cpp:449
Name
StringHandle Name
Definition: PreprocessorTracker.cpp:525
clang::tidy::readability::FunctionSizeCheck::storeOptions
void storeOptions(ClangTidyOptions::OptionMap &Opts) override
Should store all options supported by this check with their current values or default values for opti...
Definition: FunctionSizeCheck.cpp:99
clang::tidy::ClangTidyCheck
Base class for all clang-tidy checks.
Definition: ClangTidy.h:127
TrackedParent
std::vector< bool > TrackedParent
Definition: FunctionSizeCheck.cpp:85
NestingThresholders
std::vector< SourceLocation > NestingThresholders
Definition: FunctionSizeCheck.cpp:82
Branches
unsigned Branches
Definition: FunctionSizeCheck.cpp:80
clang::tidy::ClangTidyCheck::Options
OptionsView Options
Definition: ClangTidy.h:183
clang::tidy::ClangTidyOptions::OptionMap
std::map< std::string, std::string > OptionMap
Definition: ClangTidyOptions.h:99
Info
FunctionInfo Info
Definition: FunctionSizeCheck.cpp:84
clang
Definition: AndroidTidyModule.cpp:28
CurrentNestingLevel
unsigned CurrentNestingLevel
Definition: FunctionSizeCheck.cpp:86
clang::tidy::ClangTidyContext
Every ClangTidyCheck reports errors through a DiagnosticsEngine provided by this context.
Definition: ClangTidyDiagnosticConsumer.h:104
clang::tidy::readability::FunctionSizeCheck::check
void check(const ast_matchers::MatchFinder::MatchResult &Result) override
ClangTidyChecks that register ASTMatchers should do the actual work in here.
Definition: FunctionSizeCheck.cpp:111
Statements
unsigned Statements
Definition: FunctionSizeCheck.cpp:79
FunctionSizeCheck.h
NestingThreshold
unsigned NestingThreshold
Definition: FunctionSizeCheck.cpp:81
clang::tidy::readability::FunctionSizeCheck::registerMatchers
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.
Definition: FunctionSizeCheck.cpp:107
clang::tidy::ClangTidyCheck::diag
DiagnosticBuilder diag(SourceLocation Loc, StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning)
Add a diagnostic with the check&#39;s name.
Definition: ClangTidy.cpp:416
Lines
unsigned Lines
Definition: FunctionSizeCheck.cpp:78