Uniform initialisation for cpp11

clang-tools-extra/CMakeLists.txt

@@ -15,8 +15,8 @@ add_subdirectory(tool-template)
 
 # Add the common testsuite after all the tools.
 if(CLANG_INCLUDE_TESTS)
-add_subdirectory(test)
-add_subdirectory(unittests)
+  add_subdirectory(test)
+  add_subdirectory(unittests)
 endif()
 
 option(CLANG_TOOLS_EXTRA_INCLUDE_DOCS "Generate build targets for the Clang Extra Tools docs."

clang-tools-extra/clang-tidy/cppcoreguidelines/CMakeLists.txt

@@ -2,6 +2,7 @@ set(LLVM_LINK_COMPONENTS support)
 
 add_clang_library(clangTidyCppCoreGuidelinesModule
   AvoidGotoCheck.cpp
+  ConstCorrectnessCheck.cpp
   CppCoreGuidelinesTidyModule.cpp
   InitVariablesCheck.cpp
   InterfacesGlobalInitCheck.cpp
@@ -23,6 +24,7 @@ add_clang_library(clangTidyCppCoreGuidelinesModule
   SpecialMemberFunctionsCheck.cpp
 
   LINK_LIBS
+  clangAnalysis
   clangAST
   clangASTMatchers
   clangBasic

clang-tools-extra/clang-tidy/cppcoreguidelines/ConstCorrectnessCheck.cpp

@@ -0,0 +1,178 @@
+//===--- ConstCorrectnessCheck.cpp - clang-tidy -----------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "../utils/FixItHintUtils.h"
+#include "ConstCorrectnessCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace cppcoreguidelines {
+
+namespace {
+// FIXME: This matcher exists in some other code-review as well.
+// It should probably move to ASTMatchers.
+AST_MATCHER(VarDecl, isLocal) { return Node.isLocalVarDecl(); }
+AST_MATCHER_P(DeclStmt, containsDeclaration2,
+              ast_matchers::internal::Matcher<Decl>, InnerMatcher) {
+  return ast_matchers::internal::matchesFirstInPointerRange(
+      InnerMatcher, Node.decl_begin(), Node.decl_end(), Finder, Builder);
+}
+AST_MATCHER(ReferenceType, isSpelledAsLValue) {
+  return Node.isSpelledAsLValue();
+}
+AST_MATCHER(Type, isDependentType) { return Node.isDependentType(); }
+} // namespace
+
+void ConstCorrectnessCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
+  Options.store(Opts, "AnalyzeValues", AnalyzeValues);
+  Options.store(Opts, "AnalyzeReferences", AnalyzeReferences);
+  Options.store(Opts, "WarnPointersAsValues", WarnPointersAsValues);
+
+  Options.store(Opts, "TransformValues", TransformValues);
+  Options.store(Opts, "TransformReferences", TransformReferences);
+  Options.store(Opts, "TransformPointersAsValues", TransformPointersAsValues);
+}
+
+void ConstCorrectnessCheck::registerMatchers(MatchFinder *Finder) {
+  const auto ConstType = hasType(isConstQualified());
+  const auto ConstReference = hasType(references(isConstQualified()));
+  const auto RValueReference = hasType(
+      referenceType(anyOf(rValueReferenceType(), unless(isSpelledAsLValue()))));
+
+  const auto TemplateType = anyOf(
+      hasType(hasCanonicalType(templateTypeParmType())),
+      hasType(substTemplateTypeParmType()), hasType(isDependentType()),
+      // References to template types, their substitutions or typedefs to
+      // template types need to be considered as well.
+      hasType(referenceType(pointee(hasCanonicalType(templateTypeParmType())))),
+      hasType(referenceType(pointee(substTemplateTypeParmType()))));
+
+  const auto AutoTemplateType = varDecl(
+      anyOf(hasType(autoType()), hasType(referenceType(pointee(autoType()))),
+            hasType(pointerType(pointee(autoType())))),
+      hasInitializer(isInstantiationDependent()));
+
+  const auto FunctionPointerRef =
+      hasType(hasCanonicalType(referenceType(pointee(functionType()))));
+
+  // Match local variables which could be 'const' if not modified later.
+  // Example: `int i = 10` would match `int i`.
+  const auto LocalValDecl = varDecl(
+      allOf(isLocal(), hasInitializer(anything()),
+            unless(anyOf(ConstType, ConstReference, TemplateType,
+                         AutoTemplateType, RValueReference, FunctionPointerRef,
+                         hasType(cxxRecordDecl(isLambda())), isImplicit()))));
+
+  // Match the function scope for which the analysis of all local variables
+  // shall be run.
+  const auto FunctionScope = functionDecl(hasBody(
+      compoundStmt(findAll(declStmt(allOf(containsDeclaration2(
+                                              LocalValDecl.bind("local-value")),
+                                          unless(has(decompositionDecl()))))
+                               .bind("decl-stmt")))
+          .bind("scope")));
+
+  Finder->addMatcher(FunctionScope, this);
+}
+
+/// Classify for a variable in what the Const-Check is interested.
+enum class VariableCategory { Value, Reference, Pointer };
+
+void ConstCorrectnessCheck::check(const MatchFinder::MatchResult &Result) {
+  const auto *LocalScope = Result.Nodes.getNodeAs<CompoundStmt>("scope");
+  assert(LocalScope && "Did not match scope for local variable");
+  registerScope(LocalScope, Result.Context);
+
+  const auto *Variable = Result.Nodes.getNodeAs<VarDecl>("local-value");
+  assert(Variable && "Did not match local variable definition");
+
+  VariableCategory VC = VariableCategory::Value;
+  if (Variable->getType()->isReferenceType())
+    VC = VariableCategory::Reference;
+  if (Variable->getType()->isPointerType())
+    VC = VariableCategory::Pointer;
+
+  // Each variable can only in one category: Value, Pointer, Reference.
+  // Analysis can be controlled for every category.
+  if (VC == VariableCategory::Reference && !AnalyzeReferences)
+    return;
+
+  if (VC == VariableCategory::Reference &&
+      Variable->getType()->getPointeeType()->isPointerType() &&
+      !WarnPointersAsValues)
+    return;
+
+  if (VC == VariableCategory::Pointer && !WarnPointersAsValues)
+    return;
+
+  if (VC == VariableCategory::Value && !AnalyzeValues)
+    return;
+
+  // Offload const-analysis to utility function.
+  if (ScopesCache[LocalScope]->isMutated(Variable))
+    return;
+
+  auto Diag = diag(Variable->getBeginLoc(),
+                   "variable %0 of type %1 can be declared 'const'")
+              << Variable << Variable->getType();
+
+  const auto *VarDeclStmt = Result.Nodes.getNodeAs<DeclStmt>("decl-stmt");
+
+  // It can not be guaranteed that the variable is declared isolated, therefore
+  // a transformation might effect the other variables as well and be incorrect.
+  if (VarDeclStmt == nullptr || !VarDeclStmt->isSingleDecl())
+    return;
+
+  using namespace utils::fixit;
+  using llvm::Optional;
+  if (VC == VariableCategory::Value && TransformValues) {
+    if (Optional<FixItHint> Fix = addQualifierToVarDecl(
+            *Variable, *Result.Context, DeclSpec::TQ_const,
+            QualifierTarget::Value, QualifierPolicy::Left)) {
+      Diag << *Fix;
+      // FIXME: Add '{}' for default initialization if no user-defined default
+      // constructor exists and there is no initializer.
+    }
+    return;
+  }
+
+  if (VC == VariableCategory::Reference && TransformReferences) {
+    if (Optional<FixItHint> Fix = addQualifierToVarDecl(
+            *Variable, *Result.Context, DeclSpec::TQ_const,
+            QualifierTarget::Value, QualifierPolicy::Left))
+      Diag << *Fix;
+    return;
+  }
+
+  if (VC == VariableCategory::Pointer) {
+    if (WarnPointersAsValues && TransformPointersAsValues) {
+      if (Optional<FixItHint> Fix = addQualifierToVarDecl(
+              *Variable, *Result.Context, DeclSpec::TQ_const,
+              QualifierTarget::Value, QualifierPolicy::Left))
+        Diag << *Fix;
+    }
+    return;
+  }
+}
+
+void ConstCorrectnessCheck::registerScope(const CompoundStmt *LocalScope,
+                                          ASTContext *Context) {
+  if (ScopesCache.find(LocalScope) == ScopesCache.end())
+    ScopesCache.insert(std::make_pair(
+        LocalScope,
+        std::make_unique<ExprMutationAnalyzer>(*LocalScope, *Context)));
+}
+
+} // namespace cppcoreguidelines
+} // namespace tidy
+} // namespace clang

clang-tools-extra/clang-tidy/cppcoreguidelines/ConstCorrectnessCheck.h

@@ -0,0 +1,59 @@
+//===--- ConstCorrectnessCheck.h - clang-tidy -------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_CONSTCORRECTNESSCHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_CONSTCORRECTNESSCHECK_H
+
+#include "../ClangTidy.h"
+#include "clang/Analysis/Analyses/ExprMutationAnalyzer.h"
+
+namespace clang {
+namespace tidy {
+
+namespace cppcoreguidelines {
+
+/// This check warns on variables which could be declared const but are not.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/cppcoreguidelines-const.html
+class ConstCorrectnessCheck : public ClangTidyCheck {
+public:
+  ConstCorrectnessCheck(StringRef Name, ClangTidyContext *Context)
+      : ClangTidyCheck(Name, Context),
+        AnalyzeValues(Options.get("AnalyzeValues", 1)),
+        AnalyzeReferences(Options.get("AnalyzeReferences", 1)),
+        WarnPointersAsValues(Options.get("WarnPointersAsValues", 0)),
+        TransformValues(Options.get("TransformValues", 1)),
+        TransformReferences(Options.get("TransformReferences", 1)),
+        TransformPointersAsValues(Options.get("TransformPointersAsValues", 0)) {
+  }
+
+  void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+
+private:
+  void registerScope(const CompoundStmt *LocalScope, ASTContext *Context);
+
+  using MutationAnalyzer = std::unique_ptr<ExprMutationAnalyzer>;
+  llvm::DenseMap<const CompoundStmt *, MutationAnalyzer> ScopesCache;
+
+  const bool AnalyzeValues;
+  const bool AnalyzeReferences;
+  const bool WarnPointersAsValues;
+
+  const bool TransformValues;
+  const bool TransformReferences;
+  const bool TransformPointersAsValues;
+};
+
+} // namespace cppcoreguidelines
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_CONSTCORRECTNESSCHECK_H

clang-tools-extra/clang-tidy/cppcoreguidelines/CppCoreGuidelinesTidyModule.cpp

@@ -15,6 +15,7 @@
 #include "../modernize/UseOverrideCheck.h"
 #include "../readability/MagicNumbersCheck.h"
 #include "AvoidGotoCheck.h"
+#include "ConstCorrectnessCheck.h"
 #include "InitVariablesCheck.h"
 #include "InterfacesGlobalInitCheck.h"
 #include "MacroUsageCheck.h"
@@ -48,6 +49,8 @@ class CppCoreGuidelinesModule : public ClangTidyModule {
         "cppcoreguidelines-avoid-goto");
     CheckFactories.registerCheck<readability::MagicNumbersCheck>(
         "cppcoreguidelines-avoid-magic-numbers");
+    CheckFactories.registerCheck<ConstCorrectnessCheck>(
+        "cppcoreguidelines-const-correctness");
     CheckFactories.registerCheck<modernize::UseOverrideCheck>(
         "cppcoreguidelines-explicit-virtual-functions");
     CheckFactories.registerCheck<InitVariablesCheck>(

clang-tools-extra/clang-tidy/cppcoreguidelines/InitVariablesCheck.cpp

@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include <regex>
+
 #include "InitVariablesCheck.h"
 
 #include "clang/AST/ASTContext.h"
@@ -26,7 +28,9 @@ InitVariablesCheck::InitVariablesCheck(StringRef Name,
     : ClangTidyCheck(Name, Context),
       IncludeStyle(utils::IncludeSorter::parseIncludeStyle(
           Options.getLocalOrGlobal("IncludeStyle", "llvm"))),
-      MathHeader(Options.get("MathHeader", "math.h")) {}
+      MathHeader(getLangOpts().CPlusPlus11
+                     ? Options.get("MathHeader", "cmath")
+                     : Options.get("MathHeader", "math.h")) {}
 
 void InitVariablesCheck::registerMatchers(MatchFinder *Finder) {
   std::string BadDecl = "badDecl";
@@ -75,9 +79,11 @@ void InitVariablesCheck::check(const MatchFinder::MatchResult &Result) {
   const char *InitializationString = nullptr;
   bool AddMathInclude = false;
 
-  if (TypePtr->isIntegerType())
+  if (TypePtr->isBooleanType()) {
+    InitializationString = " = false";
+  } else if (TypePtr->isIntegerType()) {
     InitializationString = " = 0";
-  else if (TypePtr->isFloatingType()) {
+  } else if (TypePtr->isFloatingType()) {
     InitializationString = " = NAN";
     AddMathInclude = true;
   } else if (TypePtr->isAnyPointerType()) {
@@ -87,6 +93,12 @@ void InitVariablesCheck::check(const MatchFinder::MatchResult &Result) {
       InitializationString = " = NULL";
   }
 
+  if (InitializationString && getLangOpts().CPlusPlus11) {
+    std::regex re(" = (.*)");
+    InitializationString =
+        std::regex_replace(InitializationString, re, "{$1}").c_str();
+  }
+
   if (InitializationString) {
     auto Diagnostic =
         diag(MatchedDecl->getLocation(), "variable %0 is not initialized")

clang-tools-extra/clang-tidy/cppcoreguidelines/helper/fix_double_const.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+
+# http://redsymbol.net/articles/unofficial-bash-strict-mode/
+set -euo pipefail
+
+BASEDIR=$1
+
+echo "Fixing instances of double const qualification for files in $BASEDIR..."
+for i in $(find $BASEDIR -type f -iregex '.*\.\(h\|hxx\|hpp\|hh\|c\|cpp\|cxx\|cc\)$');do
+    echo "Checking $i"
+    sed -i 's/const const/const/g' $i
+done

clang-tools-extra/docs/ReleaseNotes.rst

@@ -138,6 +138,11 @@ New checks
   Checks whether there are local variables that are declared without an initial
   value.
 
+- New :doc:`cppcoreguidelines-const-correctness
+  <clang-tidy/checks/cppcoreguidelines-const-correctness>` check.
+
+  Suggest adding ``const`` to unmodified local variables.
+
 - New :doc:`darwin-dispatch-once-nonstatic
   <clang-tidy/checks/darwin-dispatch-once-nonstatic>` check.