[clang-tidy] Add a checker for long functions.
As this is very dependent on the code base it has some ways of configuration.
It's possible to pick between 3 modes of operation:
- Line counting: number of lines including whitespace and comments
- Statement counting: number of statements within compoundStmts.
- Branch counter
In addition a threshold can be picked, warnings are only emitted when it is met.
The thresholds can be configured via a .clang-tidy file.
Differential Revision: http://reviews.llvm.org/D4986
llvm-svn: 217768
diff --git a/clang-tools-extra/clang-tidy/misc/FunctionSize.cpp b/clang-tools-extra/clang-tidy/misc/FunctionSize.cpp
new file mode 100644
index 0000000..fe502fc
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/misc/FunctionSize.cpp
@@ -0,0 +1,104 @@
+//===--- FunctionSize.cpp - clang-tidy ------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "FunctionSize.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+
+FunctionSizeCheck::FunctionSizeCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context),
+ LineThreshold(Options.get("LineThreshold", -1U)),
+ StatementThreshold(Options.get("StatementThreshold", 800U)),
+ BranchThreshold(Options.get("BranchThreshold", -1U)) {}
+
+void FunctionSizeCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
+ Options.store(Opts, "LineThreshold", LineThreshold);
+ Options.store(Opts, "StatementThreshold", StatementThreshold);
+ Options.store(Opts, "BranchThreshold", BranchThreshold);
+}
+
+void FunctionSizeCheck::registerMatchers(MatchFinder *Finder) {
+ Finder->addMatcher(
+ functionDecl(
+ unless(isInstantiated()),
+ forEachDescendant(
+ stmt(unless(compoundStmt()),
+ hasParent(stmt(anyOf(compoundStmt(), ifStmt(),
+ anyOf(whileStmt(), doStmt(),
+ forRangeStmt(), forStmt())))))
+ .bind("stmt"))).bind("func"),
+ this);
+}
+
+void FunctionSizeCheck::check(const MatchFinder::MatchResult &Result) {
+ const auto *Func = Result.Nodes.getNodeAs<FunctionDecl>("func");
+
+ FunctionInfo &FI = FunctionInfos[Func];
+
+ // Count the lines including whitespace and comments. Really simple.
+ if (!FI.Lines) {
+ if (const Stmt *Body = Func->getBody()) {
+ SourceManager *SM = Result.SourceManager;
+ if (SM->isWrittenInSameFile(Body->getLocStart(), Body->getLocEnd())) {
+ FI.Lines = SM->getSpellingLineNumber(Body->getLocEnd()) -
+ SM->getSpellingLineNumber(Body->getLocStart());
+ }
+ }
+ }
+
+ const auto *Statement = Result.Nodes.getNodeAs<Stmt>("stmt");
+ ++FI.Statements;
+
+ // TODO: switch cases, gotos
+ if (isa<IfStmt>(Statement) || isa<WhileStmt>(Statement) ||
+ isa<ForStmt>(Statement) || isa<SwitchStmt>(Statement) ||
+ isa<DoStmt>(Statement) || isa<CXXForRangeStmt>(Statement))
+ ++FI.Branches;
+}
+
+void FunctionSizeCheck::onEndOfTranslationUnit() {
+ // If we're above the limit emit a warning.
+ for (const auto &P : FunctionInfos) {
+ const FunctionInfo &FI = P.second;
+ if (FI.Lines > LineThreshold || FI.Statements > StatementThreshold ||
+ FI.Branches > BranchThreshold) {
+ diag(P.first->getLocation(),
+ "function '%0' exceeds recommended size/complexity thresholds")
+ << P.first->getNameAsString();
+ }
+
+ if (FI.Lines > LineThreshold) {
+ diag(P.first->getLocation(),
+ "%0 lines including whitespace and comments (threshold %1)",
+ DiagnosticIDs::Note)
+ << FI.Lines << LineThreshold;
+ }
+
+ if (FI.Statements > StatementThreshold) {
+ diag(P.first->getLocation(), "%0 statements (threshold %1)",
+ DiagnosticIDs::Note)
+ << FI.Statements << StatementThreshold;
+ }
+
+ if (FI.Branches > BranchThreshold) {
+ diag(P.first->getLocation(), "%0 branches (threshold %1)",
+ DiagnosticIDs::Note)
+ << FI.Branches << BranchThreshold;
+ }
+ }
+
+ FunctionInfos.clear();
+}
+
+} // namespace tidy
+} // namespace clang