hugoeg created this revision.
hugoeg added reviewers: alexfh, hokein.
hugoeg added a project: clang-tools-extra.
Herald added a subscriber: mgorny.
warns to use 'auto' to avoid repeating the type name and fixes the issue
Replace:
std::unique_ptr<Foo> x = make_unique<Foo>(...);
with:
auto x = make_unique<Foo>(...);
https://reviews.llvm.org/D50852
Files:
clang-tidy/abseil/AbseilTidyModule.cpp
clang-tidy/abseil/AutoMakeUniqueCheck.cpp
clang-tidy/abseil/AutoMakeUniqueCheck.h
clang-tidy/abseil/CMakeLists.txt
docs/ReleaseNotes.rst
docs/clang-tidy/checks/abseil-auto-make-unique.rst
docs/clang-tidy/checks/list.rst
test/clang-tidy/abseil-auto-make-unique.cpp
Index: test/clang-tidy/abseil-auto-make-unique.cpp
===================================================================
--- test/clang-tidy/abseil-auto-make-unique.cpp
+++ test/clang-tidy/abseil-auto-make-unique.cpp
@@ -0,0 +1,115 @@
+// RUN: %check_clang_tidy %s abseil-auto-make-unique %t
+
+namespace std {
+template <typename T>
+struct default_delete {};
+
+template <typename T, typename D = default_delete<T>>
+class unique_ptr {
+ public:
+ unique_ptr();
+ ~unique_ptr();
+ explicit unique_ptr(T*);
+ template <typename U, typename E>
+ unique_ptr(unique_ptr<U, E>&&);
+};
+template <typename T, typename... Args>
+unique_ptr<T> make_unique(Args&&...);
+} // namespace std
+
+namespace absl {
+template <typename T, typename... Args>
+std::unique_ptr<T> MakeUnique(Args&&...);
+template <typename T, typename... Args>
+std::unique_ptr<T> make_unique(Args&&...);
+} // namespace absl
+using absl::make_unique;
+
+typedef int integer;
+
+struct Base {};
+struct Derived : public Base {};
+
+void Primitive() {
+ std::unique_ptr<int> x = absl::make_unique<int>();
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use 'auto' to avoid repeating the type name
+ // CHECK-FIXES: auto x = absl::make_unique<int>();
+
+ std::unique_ptr< int >y = absl::make_unique<int>();
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use 'auto' to avoid repeating the type name
+ // CHECK-FIXES: auto y = absl::make_unique<int>();
+
+ const std::unique_ptr<int> z = absl::make_unique<int>();
+ // CHECK-MESSAGES: :[[@LINE-1]]:9: warning: use 'auto' to avoid repeating the type name
+ // CHECK-FIXES: const auto z = absl::make_unique<int>();
+
+ std::unique_ptr<const int> t = absl::make_unique<int>();
+}
+
+void Typedefs() {
+ std::unique_ptr<int> x = absl::make_unique<integer>();
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use 'auto' to avoid repeating the type name
+ // CHECK-FIXES: auto x = absl::make_unique<integer>();
+
+ std::unique_ptr<integer> y = absl::make_unique<int>();
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use 'auto' to avoid repeating the type name
+ // CHECK-FIXES: auto y = absl::make_unique<int>();
+
+ std::unique_ptr<integer> z = absl::make_unique<integer>();
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use 'auto' to avoid repeating the type name
+ // CHECK-FIXES: auto z = absl::make_unique<integer>();
+}
+
+void Class() {
+ std::unique_ptr<Base> base = make_unique<Base>();
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use 'auto' to avoid repeating the type name
+ // CHECK-FIXES: auto base = make_unique<Base>();
+
+ std::unique_ptr<Base> base2(make_unique<Base>());
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use 'auto' to avoid repeating the type name
+ // CHECK-FIXES: auto base2(make_unique<Base>());
+
+ // Different type. No change.
+ std::unique_ptr<Base> z = make_unique<Derived>();
+ std::unique_ptr<Base> z2(make_unique<Derived>());
+}
+
+template <typename A, typename B>
+void f() {
+ std::unique_ptr<A> x = make_unique<B>();
+}
+
+void Negatives() {
+ // Different deleter. No change.
+ struct MyDeleter {};
+ std::unique_ptr<int, MyDeleter> z3 = make_unique<int>();
+ std::unique_ptr<int, MyDeleter> z4(make_unique<int>());
+
+ f<int, int>();
+}
+
+std::unique_ptr<int> global_var = make_unique<int>();
+// CHECK-MESSAGES: :[[@LINE-1]]:1: warning: use 'auto' to avoid repeating the type name
+// CHECK-FIXES: auto global_var = make_unique<int>();
+
+struct Struct {
+ static std::unique_ptr<int> static_field;
+};
+// This code with "auto" replaced doesn't compile in GCC.
+std::unique_ptr<int> Struct::static_field = make_unique<int>();
+
+void FunctionWithStatic() {
+ static std::unique_ptr<int> static_var = make_unique<int>();
+ // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: use 'auto' to avoid repeating the type name
+ // CHECK-FIXES: auto static_var = make_unique<int>();
+}
+
+void OtherNames() {
+ std::unique_ptr<int> x = absl::MakeUnique<int>();
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use 'auto' to avoid repeating the type name
+ // CHECK-FIXES: auto x = absl::MakeUnique<int>();
+
+ std::unique_ptr<int> y = std::make_unique<int>();
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use 'auto' to avoid repeating the type name
+ // CHECK-FIXES: auto y = std::make_unique<int>();
+}
Index: docs/clang-tidy/checks/list.rst
===================================================================
--- docs/clang-tidy/checks/list.rst
+++ docs/clang-tidy/checks/list.rst
@@ -4,6 +4,7 @@
=================
.. toctree::
+ abseil-auto-make-unique
abseil-string-find-startswith
android-cloexec-accept
android-cloexec-accept4
Index: docs/clang-tidy/checks/abseil-auto-make-unique.rst
===================================================================
--- docs/clang-tidy/checks/abseil-auto-make-unique.rst
+++ docs/clang-tidy/checks/abseil-auto-make-unique.rst
@@ -0,0 +1,19 @@
+.. title:: clang-tidy - abseil-auto-make-unique
+
+abseil-auto-make-unique
+=======================
+
+The check suggests replacing:
+
+.. code-block:: c++
+
+ std::unique_ptr<Foo> x = MakeUnique<Foo>(...);
+
+with
+
+.. code-block:: c++
+
+ auto x = MakeUnique<Foo>(...);
+
+The initializer already spells the type, so it can be safely omitted from the
+declaration while making the code more readable.
Index: docs/ReleaseNotes.rst
===================================================================
--- docs/ReleaseNotes.rst
+++ docs/ReleaseNotes.rst
@@ -57,6 +57,11 @@
Improvements to clang-tidy
--------------------------
+- New :doc:`abseil-auto-make-unique
+ <clang-tidy/checks/abseil-auto-make-unique>` check.
+
+ FIXME: add release notes.
+
- New :doc:`readability-magic-numbers
<clang-tidy/checks/readability-magic-numbers>` check.
Index: clang-tidy/abseil/CMakeLists.txt
===================================================================
--- clang-tidy/abseil/CMakeLists.txt
+++ clang-tidy/abseil/CMakeLists.txt
@@ -2,6 +2,7 @@
add_clang_library(clangTidyAbseilModule
AbseilTidyModule.cpp
+ AutoMakeUniqueCheck.cpp
StringFindStartswithCheck.cpp
LINK_LIBS
Index: clang-tidy/abseil/AutoMakeUniqueCheck.h
===================================================================
--- clang-tidy/abseil/AutoMakeUniqueCheck.h
+++ clang-tidy/abseil/AutoMakeUniqueCheck.h
@@ -0,0 +1,38 @@
+//===--- AutoMakeUniqueCheck.h - clang-tidy----------------------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ABSEIL_AUTOMAKEUNIQUECHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ABSEIL_AUTOMAKEUNIQUECHECK_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace abseil {
+
+/// Replace:
+/// std::unique_ptr<Foo> x = make_unique<Foo>(...);
+/// with:
+/// auto x = make_unique<Foo>(...);
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/abseil-auto-make-unique.html
+class AutoMakeUniqueCheck : public ClangTidyCheck {
+public:
+ AutoMakeUniqueCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context) {}
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace abseil
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ABSEIL_AUTOMAKEUNIQUECHECK_H
Index: clang-tidy/abseil/AutoMakeUniqueCheck.cpp
===================================================================
--- clang-tidy/abseil/AutoMakeUniqueCheck.cpp
+++ clang-tidy/abseil/AutoMakeUniqueCheck.cpp
@@ -0,0 +1,88 @@
+//===--- AutoMakeUniqueCheck.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 "AutoMakeUniqueCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace abseil {
+
+void AutoMakeUniqueCheck::registerMatchers(MatchFinder* finder) {
+ if (!getLangOpts().CPlusPlus) return;
+
+ using clang::ast_matchers::isTemplateInstantiation;
+ auto is_instantiation = decl(anyOf(cxxRecordDecl(isTemplateInstantiation()),
+ varDecl(isTemplateInstantiation()),
+ functionDecl(isTemplateInstantiation())));
+ // There should be no additional expressions inbetween.
+ // E.g. this statement contains implicitCastExpr which makes it not eligible:
+ // std::unique_ptr<Base> p = make_unique<Derived>();
+ finder->addMatcher(
+ varDecl(has(exprWithCleanups(has(cxxConstructExpr(
+ has(ignoringParenImpCasts(cxxBindTemporaryExpr(
+ has(ignoringParenImpCasts(callExpr(callee(functionDecl(
+ hasAnyName("absl::MakeUnique", "absl::make_unique",
+ "gtl::MakeUnique", "std::make_unique"),
+ decl().bind("make_unique_decl"))))))))))))),
+ hasType(classTemplateSpecializationDecl(
+ hasName("std::unique_ptr"),
+ hasTemplateArgument(
+ 1, refersToType(qualType(hasDeclaration(cxxRecordDecl(
+ hasName("std::default_delete")))))))),
+ unless(hasType(autoType())),
+ unless(anyOf(is_instantiation, hasAncestor(is_instantiation))))
+ .bind("var_decl"),
+ this);
+}
+
+const Type* GetUniquePtrType(const VarDecl* var) {
+ const auto* unique = dyn_cast_or_null<ClassTemplateSpecializationDecl>(
+ var->getType()->getAsCXXRecordDecl());
+ if (!unique) return nullptr;
+ QualType type = unique->getTemplateArgs().get(0).getAsType();
+ return type->getUnqualifiedDesugaredType();
+}
+
+const Type* GetMakeUniqueType(const FunctionDecl* make_unique_decl) {
+ const auto& template_arg =
+ make_unique_decl->getTemplateSpecializationInfo()->TemplateArguments->get(
+ 0);
+ return template_arg.getAsType()->getUnqualifiedDesugaredType();
+}
+
+void AutoMakeUniqueCheck::check(
+ const ast_matchers::MatchFinder::MatchResult& result) {
+ const auto* var_decl = result.Nodes.getNodeAs<VarDecl>("var_decl");
+ const auto* make_unique_decl =
+ result.Nodes.getNodeAs<FunctionDecl>("make_unique_decl");
+ if (var_decl->isOutOfLine()) {
+ // "auto Struct::field = make_unique<...>();" doesn't work in GCC.
+ return;
+ }
+ if (GetUniquePtrType(var_decl) != GetMakeUniqueType(make_unique_decl)) {
+ // The variable and the make_unique expression do not share the same type.
+ // Ignore this.
+ return;
+ }
+
+ diag(var_decl->getTypeSpecStartLoc(),
+ "use 'auto' to avoid repeating the type name")
+ << FixItHint::CreateReplacement(
+ clang::CharSourceRange::getCharRange(
+ var_decl->getTypeSpecStartLoc(), var_decl->getLocation()),
+ "auto ");
+}
+
+} // namespace abseil
+} // namespace tidy
+} // namespace clang
Index: clang-tidy/abseil/AbseilTidyModule.cpp
===================================================================
--- clang-tidy/abseil/AbseilTidyModule.cpp
+++ clang-tidy/abseil/AbseilTidyModule.cpp
@@ -10,6 +10,7 @@
#include "../ClangTidy.h"
#include "../ClangTidyModule.h"
#include "../ClangTidyModuleRegistry.h"
+#include "AutoMakeUniqueCheck.h"
#include "StringFindStartswithCheck.h"
namespace clang {
@@ -19,6 +20,8 @@
class AbseilModule : public ClangTidyModule {
public:
void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override {
+ CheckFactories.registerCheck<AutoMakeUniqueCheck>(
+ "abseil-auto-make-unique");
CheckFactories.registerCheck<StringFindStartswithCheck>(
"abseil-string-find-startswith");
}
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