[clang-tidy] Move some of the misc checks to readability/

Summary:
Some of the misc checks belong to readability/. I'm moving them there
without changing check names for now. As the next step, I want to register some
of these checks in the google and llvm modules with suitable settings (e.g.
BracesAroundStatementsCheck). I'm not sure if we want to create a "readability"
module, probably not.

Reviewers: djasper

Reviewed By: djasper

Subscribers: curdeius, cfe-commits

Differential Revision: http://reviews.llvm.org/D5792

llvm-svn: 219786

1 files changed, 106 insertions, 0 deletions

diff --git a/clang-tools-extra/clang-tidy/readability/FunctionSize.cpp b/clang-tools-extra/clang-tidy/readability/FunctionSize.cpp
new file mode 100644
index 00000000000..0c980e6a996
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/readability/FunctionSize.cpp
@@ -0,0 +1,106 @@
+//===--- 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 {
+namespace readability {
+
+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 readability
+} // namespace tidy
+} // namespace clang