[clang-tools-extra] r332519 - Add a new check, readability-simplify-subscript-expr, that diagnoses array subscript expressions that can be simplified.
Aaron Ballman via cfe-commits
cfe-commits at lists.llvm.org
Wed May 16 13:12:07 PDT 2018
Author: aaronballman
Date: Wed May 16 13:12:06 2018
New Revision: 332519
URL: http://llvm.org/viewvc/llvm-project?rev=332519&view=rev
Log:
Add a new check, readability-simplify-subscript-expr, that diagnoses array subscript expressions that can be simplified.
Currently, diagnoses code that calls container.data()[some_index] when the container exposes a suitable operator[]() method that can be used directly.
Patch by Shuai Wang.
Added:
clang-tools-extra/trunk/clang-tidy/readability/SimplifySubscriptExprCheck.cpp
clang-tools-extra/trunk/clang-tidy/readability/SimplifySubscriptExprCheck.h
clang-tools-extra/trunk/docs/clang-tidy/checks/readability-simplify-subscript-expr.rst
clang-tools-extra/trunk/test/clang-tidy/readability-simplify-subscript-expr.cpp
Modified:
clang-tools-extra/trunk/clang-tidy/readability/CMakeLists.txt
clang-tools-extra/trunk/clang-tidy/readability/ReadabilityTidyModule.cpp
clang-tools-extra/trunk/docs/ReleaseNotes.rst
clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst
Modified: clang-tools-extra/trunk/clang-tidy/readability/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/readability/CMakeLists.txt?rev=332519&r1=332518&r2=332519&view=diff
==============================================================================
--- clang-tools-extra/trunk/clang-tidy/readability/CMakeLists.txt (original)
+++ clang-tools-extra/trunk/clang-tidy/readability/CMakeLists.txt Wed May 16 13:12:06 2018
@@ -25,6 +25,7 @@ add_clang_library(clangTidyReadabilityMo
RedundantSmartptrGetCheck.cpp
RedundantStringInitCheck.cpp
SimplifyBooleanExprCheck.cpp
+ SimplifySubscriptExprCheck.cpp
StaticAccessedThroughInstanceCheck.cpp
StaticDefinitionInAnonymousNamespaceCheck.cpp
StringCompareCheck.cpp
Modified: clang-tools-extra/trunk/clang-tidy/readability/ReadabilityTidyModule.cpp
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/readability/ReadabilityTidyModule.cpp?rev=332519&r1=332518&r2=332519&view=diff
==============================================================================
--- clang-tools-extra/trunk/clang-tidy/readability/ReadabilityTidyModule.cpp (original)
+++ clang-tools-extra/trunk/clang-tidy/readability/ReadabilityTidyModule.cpp Wed May 16 13:12:06 2018
@@ -32,6 +32,7 @@
#include "RedundantStringCStrCheck.h"
#include "RedundantStringInitCheck.h"
#include "SimplifyBooleanExprCheck.h"
+#include "SimplifySubscriptExprCheck.h"
#include "StaticAccessedThroughInstanceCheck.h"
#include "StaticDefinitionInAnonymousNamespaceCheck.h"
#include "StringCompareCheck.h"
@@ -72,6 +73,8 @@ public:
"readability-redundant-function-ptr-dereference");
CheckFactories.registerCheck<RedundantMemberInitCheck>(
"readability-redundant-member-init");
+ CheckFactories.registerCheck<SimplifySubscriptExprCheck>(
+ "readability-simplify-subscript-expr");
CheckFactories.registerCheck<StaticAccessedThroughInstanceCheck>(
"readability-static-accessed-through-instance");
CheckFactories.registerCheck<StaticDefinitionInAnonymousNamespaceCheck>(
Added: clang-tools-extra/trunk/clang-tidy/readability/SimplifySubscriptExprCheck.cpp
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/readability/SimplifySubscriptExprCheck.cpp?rev=332519&view=auto
==============================================================================
--- clang-tools-extra/trunk/clang-tidy/readability/SimplifySubscriptExprCheck.cpp (added)
+++ clang-tools-extra/trunk/clang-tidy/readability/SimplifySubscriptExprCheck.cpp Wed May 16 13:12:06 2018
@@ -0,0 +1,76 @@
+//===--- SimplifySubscriptExprCheck.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 "SimplifySubscriptExprCheck.h"
+#include "../utils/OptionsUtils.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace readability {
+
+static const char kDefaultTypes[] =
+ "::std::basic_string;::std::basic_string_view;::std::vector;::std::array";
+
+SimplifySubscriptExprCheck::SimplifySubscriptExprCheck(
+ StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context), Types(utils::options::parseStringList(
+ Options.get("Types", kDefaultTypes))) {
+}
+
+void SimplifySubscriptExprCheck::registerMatchers(MatchFinder *Finder) {
+ if (!getLangOpts().CPlusPlus)
+ return;
+
+ const auto TypesMatcher = hasUnqualifiedDesugaredType(
+ recordType(hasDeclaration(cxxRecordDecl(hasAnyName(
+ llvm::SmallVector<StringRef, 8>(Types.begin(), Types.end()))))));
+
+ Finder->addMatcher(
+ arraySubscriptExpr(hasBase(ignoringParenImpCasts(
+ cxxMemberCallExpr(
+ has(memberExpr().bind("member")),
+ on(hasType(qualType(
+ unless(anyOf(substTemplateTypeParmType(),
+ hasDescendant(substTemplateTypeParmType()))),
+ anyOf(TypesMatcher, pointerType(pointee(TypesMatcher)))))),
+ callee(namedDecl(hasName("data"))))
+ .bind("call")))),
+ this);
+}
+
+void SimplifySubscriptExprCheck::check(const MatchFinder::MatchResult &Result) {
+ const auto *Call = Result.Nodes.getNodeAs<CXXMemberCallExpr>("call");
+ if (Result.Context->getSourceManager().isMacroBodyExpansion(
+ Call->getExprLoc()))
+ return;
+
+ const auto *Member = Result.Nodes.getNodeAs<MemberExpr>("member");
+ auto DiagBuilder =
+ diag(Member->getMemberLoc(),
+ "accessing an element of the container does not require a call to "
+ "'data()'; did you mean to use 'operator[]'?");
+ if (Member->isArrow())
+ DiagBuilder << FixItHint::CreateInsertion(Member->getLocStart(), "(*")
+ << FixItHint::CreateInsertion(Member->getOperatorLoc(), ")");
+ DiagBuilder << FixItHint::CreateRemoval(
+ {Member->getOperatorLoc(), Call->getLocEnd()});
+}
+
+void SimplifySubscriptExprCheck::storeOptions(
+ ClangTidyOptions::OptionMap &Opts) {
+ Options.store(Opts, "Types", utils::options::serializeStringList(Types));
+}
+
+} // namespace readability
+} // namespace tidy
+} // namespace clang
Added: clang-tools-extra/trunk/clang-tidy/readability/SimplifySubscriptExprCheck.h
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/readability/SimplifySubscriptExprCheck.h?rev=332519&view=auto
==============================================================================
--- clang-tools-extra/trunk/clang-tidy/readability/SimplifySubscriptExprCheck.h (added)
+++ clang-tools-extra/trunk/clang-tidy/readability/SimplifySubscriptExprCheck.h Wed May 16 13:12:06 2018
@@ -0,0 +1,38 @@
+//===--- SimplifySubscriptExprCheck.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_READABILITY_SIMPLIFYSUBSCRIPTEXPRCHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_SIMPLIFYSUBSCRIPTEXPRCHECK_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace readability {
+
+/// Simplifies subscript expressions.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/readability-simplify-subscript-expr.html
+class SimplifySubscriptExprCheck : public ClangTidyCheck {
+public:
+ SimplifySubscriptExprCheck(StringRef Name, ClangTidyContext *Context);
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+ void storeOptions(ClangTidyOptions::OptionMap& Opts) override;
+
+private:
+ const std::vector<std::string> Types;
+};
+
+} // namespace readability
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_SIMPLIFYSUBSCRIPTEXPRCHECK_H
Modified: clang-tools-extra/trunk/docs/ReleaseNotes.rst
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/docs/ReleaseNotes.rst?rev=332519&r1=332518&r2=332519&view=diff
==============================================================================
--- clang-tools-extra/trunk/docs/ReleaseNotes.rst (original)
+++ clang-tools-extra/trunk/docs/ReleaseNotes.rst Wed May 16 13:12:06 2018
@@ -151,6 +151,11 @@ Improvements to clang-tidy
Warns or suggests alternatives if SIMD intrinsics are used which can be replaced by
``std::experimental::simd`` operations.
+- New :doc:`readability-simplify-subscript-expr
+ <clang-tidy/checks/readability-simplify-subscript-expr>` check.
+
+ Simplifies subscript expressions like ``s.data()[i]`` into ``s[i]``.
+
- New :doc:`zircon-temporary-objects
<clang-tidy/checks/zircon-temporary-objects>` check.
Modified: clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst?rev=332519&r1=332518&r2=332519&view=diff
==============================================================================
--- clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst (original)
+++ clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst Wed May 16 13:12:06 2018
@@ -227,6 +227,7 @@ Clang-Tidy Checks
readability-redundant-string-cstr
readability-redundant-string-init
readability-simplify-boolean-expr
+ readability-simplify-subscript-expr
readability-static-accessed-through-instance
readability-static-definition-in-anonymous-namespace
readability-string-compare
Added: clang-tools-extra/trunk/docs/clang-tidy/checks/readability-simplify-subscript-expr.rst
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/docs/clang-tidy/checks/readability-simplify-subscript-expr.rst?rev=332519&view=auto
==============================================================================
--- clang-tools-extra/trunk/docs/clang-tidy/checks/readability-simplify-subscript-expr.rst (added)
+++ clang-tools-extra/trunk/docs/clang-tidy/checks/readability-simplify-subscript-expr.rst Wed May 16 13:12:06 2018
@@ -0,0 +1,23 @@
+.. title:: clang-tidy - readability-simplify-subscript-expr
+
+readability-simplify-subscript-expr
+===================================
+
+This check simplifies subscript expressions. Currently this covers calling
+``.data()`` and immediately doing an array subscript operation to obtain a
+single element, in which case simply calling ``operator[]`` suffice.
+
+Examples:
+
+.. code-block:: c++
+
+ std::string s = ...;
+ char c = s.data()[i]; // char c = s[i];
+
+Options
+-------
+
+.. option:: Types
+
+ The list of type(s) that triggers this check. Default is
+ `::std::basic_string;::std::basic_string_view;::std::vector;::std::array`
Added: clang-tools-extra/trunk/test/clang-tidy/readability-simplify-subscript-expr.cpp
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/test/clang-tidy/readability-simplify-subscript-expr.cpp?rev=332519&view=auto
==============================================================================
--- clang-tools-extra/trunk/test/clang-tidy/readability-simplify-subscript-expr.cpp (added)
+++ clang-tools-extra/trunk/test/clang-tidy/readability-simplify-subscript-expr.cpp Wed May 16 13:12:06 2018
@@ -0,0 +1,108 @@
+// RUN: %check_clang_tidy %s readability-simplify-subscript-expr %t \
+// RUN: -config="{CheckOptions: \
+// RUN: [{key: readability-simplify-subscript-expr.Types, \
+// RUN: value: '::std::basic_string;::std::basic_string_view;MyVector'}]}" --
+
+namespace std {
+
+template <class T>
+class basic_string {
+ public:
+ using size_type = unsigned;
+ using value_type = T;
+ using reference = value_type&;
+ using const_reference = const value_type&;
+
+ reference operator[](size_type);
+ const_reference operator[](size_type) const;
+ T* data();
+ const T* data() const;
+};
+
+using string = basic_string<char>;
+
+template <class T>
+class basic_string_view {
+ public:
+ using size_type = unsigned;
+ using const_reference = const T&;
+ using const_pointer = const T*;
+
+ constexpr const_reference operator[](size_type) const;
+ constexpr const_pointer data() const noexcept;
+};
+
+using string_view = basic_string_view<char>;
+
+}
+
+template <class T>
+class MyVector {
+ public:
+ using size_type = unsigned;
+ using const_reference = const T&;
+ using const_pointer = const T*;
+
+ const_reference operator[](size_type) const;
+ const T* data() const noexcept;
+};
+
+#define DO(x) do { x; } while (false)
+#define ACCESS(x) (x)
+#define GET(x, i) (x).data()[i]
+
+template <class T>
+class Foo {
+ public:
+ char bar(int i) {
+ return x.data()[i];
+ }
+ private:
+ T x;
+};
+
+void f(int i) {
+ MyVector<int> v;
+ int x = v.data()[i];
+ // CHECK-MESSAGES: :[[@LINE-1]]:13: warning: accessing an element of the container does not require a call to 'data()'; did you mean to use 'operator[]'? [readability-simplify-subscript-expr]
+ // CHECK-FIXES: int x = v[i];
+
+ std::string s;
+ char c1 = s.data()[i];
+ // CHECK-MESSAGES: :[[@LINE-1]]:15: warning: accessing an element
+ // CHECK-FIXES: char c1 = s[i];
+
+ std::string_view sv;
+ char c2 = sv.data()[i];
+ // CHECK-MESSAGES: :[[@LINE-1]]:16: warning: accessing an element
+ // CHECK-FIXES: char c2 = sv[i];
+
+ std::string* ps = &s;
+ char c3 = ps->data()[i];
+ // CHECK-MESSAGES: :[[@LINE-1]]:17: warning: accessing an element
+ // CHECK-FIXES: char c3 = (*ps)[i];
+
+ char c4 = (*ps).data()[i];
+ // CHECK-MESSAGES: :[[@LINE-1]]:19: warning: accessing an element
+ // CHECK-FIXES: char c4 = (*ps)[i];
+
+ DO(char c5 = s.data()[i]);
+ // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: accessing an element
+ // CHECK-FIXES: DO(char c5 = s[i]);
+
+ char c6 = ACCESS(s).data()[i];
+ // CHECK-MESSAGES: :[[@LINE-1]]:23: warning: accessing an element
+ // CHECK-FIXES: char c6 = ACCESS(s)[i];
+
+ char c7 = ACCESS(s.data())[i];
+ // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: accessing an element
+ // CHECK-FIXES: char c7 = ACCESS(s)[i];
+
+ char c8 = ACCESS(s.data()[i]);
+ // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: accessing an element
+ // CHECK-FIXES: char c8 = ACCESS(s[i]);
+
+ char c9 = GET(s, i);
+
+ char c10 = Foo<std::string>{}.bar(i);
+}
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