Extra Clang Tools 10.0.0 Release Notes

Written by the LLVM Team

Introduction

This document contains the release notes for the Extra Clang Tools, part of the Clang release 10.0.0. Here we describe the status of the Extra Clang Tools in some detail, including major improvements from the previous release and new feature work. All LLVM releases may be downloaded from the LLVM releases web site.

For more information about Clang or LLVM, including information about the latest release, please see the Clang Web Site or the LLVM Web Site.

What's New in Extra Clang Tools 10.0.0?

Some of the major new features and improvements to Extra Clang Tools are listed here. Generic improvements to Extra Clang Tools as a whole or to its underlying infrastructure are described first, followed by tool-specific sections.

Improvements to clangd

• clangd documentation is now found at https://clangd.llvm.org/

• Go-to-definition, hover, find-references etc use a new mechanism to identify what is under the cursor, which is (hopefully) more consistent and accurate.

• clangd should be able to reliably locate the standard library/SDK on macOS.

• Shutdown more cleanly on receiving a signal. In particular temporary PCH files should be cleaned up.

• Find references now works on macros.

• clangd can be more easily used remotely or in a docker container.

  The --path-mappings flag translates between local and remote paths.

• Experimental support for renaming across files (behind the --cross-file-rename flag).

• Hover now exposes more information, including the type of symbols and the value of constant expressions.

• Go to definition now works in dependent code in more cases, by assuming the primary template is used.

• Better recovery and reporting when the compile command for a file can't be fully parsed.

• Switch header/source (an extension) now uses index information in addition to filename heuristics, and is much more robust.

• Semantic selection (expand/contract selection) is supported.

• Semantic highlighting is more robust, highlights more types of tokens, and as an extension provides information about inactive preprocessor regions.

• Code completion results now include an extension field score.

  This allows clients to incorporate clangd quality signals when re-ranking code completion after client-side fuzzy-matching.

• New refactorings: define function out-of-line, define function in-line, extract function, remove using namespace directive, localize Objective-C string.

• Bug fixes and performance improvements :-)

Improvements to clang-doc

• :doc:`clang-doc <clang-doc>` now generates documentation in HTML format.

Improvements to clang-tidy

New checks

• New :doc:`bugprone-bad-signal-to-kill-thread <clang-tidy/checks/bugprone-bad-signal-to-kill-thread>` check.

  Finds pthread_kill function calls when a thread is terminated by raising SIGTERM signal.

• New :doc:`bugprone-dynamic-static-initializers <clang-tidy/checks/bugprone-dynamic-static-initializers>` check.

  Finds instances where variables with static storage are initialized dynamically in header files.

• New :doc:`bugprone-infinite-loop <clang-tidy/checks/bugprone-infinite-loop>` check.

  Finds obvious infinite loops (loops where the condition variable is not changed at all).

• New :doc:`bugprone-not-null-terminated-result <clang-tidy/checks/bugprone-not-null-terminated-result>` check

  Finds function calls where it is possible to cause a not null-terminated result.

• New :doc:`bugprone-signed-char-misuse <clang-tidy/checks/bugprone-signed-char-misuse>` check.

  Finds signed char to integer conversions which might indicate a programming error.

• New :doc:`cert-mem57-cpp <clang-tidy/checks/cert-mem57-cpp>` check.

  Checks if an object of type with extended alignment is allocated by using the default operator new.

• New :doc:`cert-oop58-cpp <clang-tidy/checks/cert-oop58-cpp>` check.

  Finds assignments to the copied object and its direct or indirect members in copy constructors and copy assignment operators.

• New :doc:`cppcoreguidelines-init-variables <clang-tidy/checks/cppcoreguidelines-init-variables>` check.

  Checks whether there are local variables that are declared without an initial value.

• New :doc:`darwin-dispatch-once-nonstatic <clang-tidy/checks/darwin-dispatch-once-nonstatic>` check.

  Finds declarations of dispatch_once_t variables without static or global storage.

• New :doc:`google-upgrade-googletest-case <clang-tidy/checks/google-upgrade-googletest-case>` check.

  Finds uses of deprecated Googletest APIs with names containing case and replaces them with equivalent APIs with suite.

• New :doc:`linuxkernel-must-use-errs <clang-tidy/checks/linuxkernel-must-use-errs>` check.

  Checks Linux kernel code to see if it uses the results from the functions in linux/err.h.

• New :doc:`llvm-prefer-register-over-unsigned <clang-tidy/checks/llvm-prefer-register-over-unsigned>` check.

  Finds historical use of unsigned to hold vregs and physregs and rewrites them to use Register

• New :doc:`objc-missing-hash <clang-tidy/checks/objc-missing-hash>` check.

  Finds Objective-C implementations that implement -isEqual: without also appropriately implementing -hash.

• New :doc:`performance-no-automatic-move <clang-tidy/checks/performance-no-automatic-move>` check.

  Finds local variables that cannot be automatically moved due to constness.

• New :doc:`performance-trivially-destructible <clang-tidy/checks/performance-trivially-destructible>` check.

  Finds types that could be made trivially-destructible by removing out-of-line defaulted destructor declarations.

• New :doc:`readability-make-member-function-const <clang-tidy/checks/readability-make-member-function-const>` check.

  Finds non-static member functions that can be made const because the functions don't use this in a non-const way.

• New :doc:`readability-qualified-auto <clang-tidy/checks/readability-qualified-auto>` check.

  Adds pointer and const qualifications to auto-typed variables that are deduced to pointers and const pointers.

• New :doc:`readability-redundant-access-specifiers <clang-tidy/checks/readability-redundant-access-specifiers>` check.

  Finds classes, structs, and unions that contain redundant member access specifiers.

New aliases

• New alias :doc:`cert-pos44-c <clang-tidy/checks/cert-pos44-c>` to :doc:`bugprone-bad-signal-to-kill-thread <clang-tidy/checks/bugprone-bad-signal-to-kill-thread>` was added.
• New alias :doc:`llvm-qualified-auto <clang-tidy/checks/llvm-qualified-auto>` to :doc:`readability-qualified-auto <clang-tidy/checks/readability-qualified-auto>` was added.

Changes in existing checks

• Improved :doc:`bugprone-posix-return <clang-tidy/checks/bugprone-posix-return>` check.

  Now also checks if any calls to pthread_* functions expect negative return values.

• Improved :doc:`hicpp-signed-bitwise <clang-tidy/checks/hicpp-signed-bitwise>` check.

  The check now supports the IgnorePositiveIntegerLiterals option.

• Improved :doc:`modernize-avoid-bind <clang-tidy/checks/modernize-avoid-bind>` check.

  The check now supports supports diagnosing and fixing arbitrary callables instead of only simple free functions. The PermissiveParameterList option has also been added to address situations where the existing fix-it logic would sometimes generate code that no longer compiles.

• The :doc:`modernize-use-equals-default <clang-tidy/checks/modernize-use-equals-default>` fix no longer adds semicolons where they would be redundant.

• Improved :doc:`modernize-use-override <clang-tidy/checks/modernize-use-override>` check.

  The check now supports the AllowOverrideAndFinal option to eliminate conflicts with gcc -Wsuggest-override or gcc -Werror=suggest-override.

• The :doc:`modernize-use-using <clang-tidy/checks/modernize-use-using>` check now converts typedefs containing struct definitions and multiple comma-separated types.

• Improved :doc:`readability-magic-numbers <clang-tidy/checks/readability-magic-numbers>` check.

  The check now supports the IgnoreBitFieldsWidths option to suppress the warning for numbers used to specify bit field widths.

  The check was updated to eliminate some false positives (such as using class enumeration as non-type template parameters, or the synthetically computed length of a static user string literal.)

• Improved :doc:`readability-redundant-member-init <clang-tidy/checks/readability-redundant-member-init>` check.

  The check now supports the IgnoreBaseInCopyConstructors option to avoid "base class 'Foo' should be explicitly initialized in the copy constructor" warnings or errors with gcc -Wextra or gcc -Werror=extra.

• The :doc:`readability-redundant-string-init <clang-tidy/checks/readability-redundant-string-init>` check now supports a StringNames option enabling its application to custom string classes.

Renamed checks

• The 'objc-avoid-spinlock' check was renamed to :doc:`darwin-avoid-spinlock <clang-tidy/checks/darwin-avoid-spinlock>`

Clang-tidy visual studio plugin

The clang-tidy-vs plugin has been removed from clang, as it's no longer maintained. Users should migrate to Clang Power Tools instead.