Written by the LLVM Team
Warning
These are in-progress notes for the upcoming Clang 3.9 release. You may prefer the Clang 3.8 Release Notes.
This document contains the release notes for the Extra Clang Tools, part of the Clang release 3.9. Here we describe the status of the Extra Clang Tools in some detail, including major improvements from the previous release and new feature work. For the general Clang release notes, see the Clang documentation. 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.
Note that if you are reading this file from a Subversion checkout or the main Clang web page, this document applies to the next release, not the current one. To see the release notes for a specific release, please see the releases page.
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.
- Feature1...
The improvements are...
The improvements are...
clang-tidy
's checks are constantly being improved to catch more issues, explain them more clearly, and provide more accurate fix-its for the issues identified. The improvements since the 3.8 release include:
- New Boost module containing checks for issues with Boost library.
New boost-use-to-string check
Finds usages of
boost::lexical_cast<std::string>
and changes it tostd::to_string
.New cert-env33-c check
Flags calls to
system()
,popen()
, and_popen()
, which execute a command processor.New cert-err34-c check
Flags calls to string-to-number conversion functions that do not verify the validity of the conversion.
New cert-flp30-c check
Flags
for
loops where the induction expression has a floating-point type.New cppcoreguidelines-interfaces-global-init check
Flags initializers of globals that access extern objects, and therefore can lead to order-of-initialization problems.
New cppcoreguidelines-pro-type-member-init check
Flags user-defined constructor definitions that do not initialize all builtin and pointer fields which leaves their memory in an undefined state.
New misc-dangling-handle check
Detects dangling references in value handlers like
std::experimental::string_view
.New misc-fold-init-type check
The check flags type mismatches in folds like
std::accumulate
that might result in loss of precision.New misc-forward-declaration-namespace check
Checks if an unused forward declaration is in a wrong namespace.
New misc-misplaced-widening-cast check
Warns when there is a explicit redundant cast of a calculation result to a bigger type.
New misc-multiple-statement-macro check
Detect multiple statement macros that are used in unbraced conditionals.
New misc-pointer-and-integral-operation check
Warns about suspicious operations involving pointers and integral types.
New misc-redundant-expression check
Warns about redundant and equivalent expressions.
New misc-sizeof-expression check
Warns about incorrect uses of
sizeof
operator.New misc-string-constructor check
Finds string constructors that are suspicious and probably errors.
New misc-string-literal-with-embedded-nul check
Warns about suspicious NUL character in string literals which may lead to truncation or invalid character escaping.
New misc-suspicious-missing-comma check
Warns about 'probably' missing comma in string literals initializer list.
New misc-suspicious-semicolon check
Finds most instances of stray semicolons that unexpectedly alter the meaning of the code.
New misc-suspicious-string-compare check
Find suspicious usage of runtime string comparison functions.
New misc-unused-using-decls check
Finds unused
using
declarations.New modernize-deprecated-headers check
Replaces C standard library headers with their C++ alternatives.
New modernize-make-shared check
Replaces creation of
std::shared_ptr
from new expression with call tostd::make_shared
.New modernize-raw-string-literal check
Selectively replaces string literals containing escaped characters with raw string literals.
New performance-faster-string-find check
Optimize calls to
std::string::find()
and friends when the needle passed is a single character string literal.New performance-implicit-cast-in-loop check
Warns about range-based loop with a loop variable of const ref type where the type of the variable does not match the one returned by the iterator.
New performance-unnecessary-value-param check
Flags value parameter declarations of expensive to copy types that are copied for each invocation but it would suffice to pass them by const reference.
New readability-avoid-const-params-in-decls check
Warns about top-level const parameters in function declarations.
New readability-deleted-default check
Warns about defaulted constructors and assignment operators that are actually deleted.
New readability-redundant-control-flow check
Looks for procedures (functions returning no value) with
return
statements at the end of the function. Such return statements are redundant.New readability-redundant-string-init check
Finds unnecessary string initializations.
New readability-static-definition-in-anonymous-namespace check
Finds static function and variable definitions in anonymous namespace.
New misc-unconventional-assign-operator check replacing old misc-assign-operator-signature check
Does not only checks for correct signature but also for correct
return
statements (returning*this
)
Fixed bugs:
- Crash when running on compile database with relative source files paths.
- Crash when running with the -fdelayed-template-parsing flag.
- The modernize-use-override check: incorrect fix-its placement around
__declspec
and other attributes.
The 3.8 release didn't include release notes for clang-tidy
. In the 3.8 release many new checks have been added to clang-tidy
:
- Checks enforcing certain rules of the CERT Secure Coding Standards:
- cert-dcl03-c (an alias to the pre-existing check misc-static-assert)
- cert-dcl50-cpp
- cert-err52-cpp
- cert-err58-cpp
- cert-err60-cpp
- cert-err61-cpp
- cert-fio38-c (an alias to the pre-existing check misc-non-copyable-objects)
- cert-oop11-cpp (an alias to the pre-existing check misc-move-constructor-init)
- Checks supporting the C++ Core Guidelines:
- cppcoreguidelines-pro-bounds-array-to-pointer-decay
- cppcoreguidelines-pro-bounds-constant-array-index
- cppcoreguidelines-pro-bounds-pointer-arithmetic
- cppcoreguidelines-pro-type-const-cast
- cppcoreguidelines-pro-type-cstyle-cast
- cppcoreguidelines-pro-type-reinterpret-cast
- cppcoreguidelines-pro-type-static-cast-downcast
- cppcoreguidelines-pro-type-union-access
- cppcoreguidelines-pro-type-vararg
- The functionality of the
clang-modernize
tool has been moved to the newmodernize
module inclang-tidy
along with a few new checks:- modernize-loop-convert
- modernize-make-unique
- modernize-pass-by-value
- modernize-redundant-void-arg
- modernize-replace-auto-ptr
- modernize-shrink-to-fit (renamed from
readability-shrink-to-fit
) - modernize-use-auto
- modernize-use-default
- modernize-use-nullptr
- modernize-use-override (renamed from
misc-use-override
)
- New checks flagging various readability-related issues:
Updated
cppcoreguidelines-pro-member-type-member-init
checkThis check now conforms to C++ Core Guidelines rule Type.6: Always Initialize a Member Variable. The check examines every record type where construction might result in an undefined memory state. These record types needing initialization have at least one default-initialized built-in, pointer, array or record type matching these criteria or a default-initialized direct base class of this kind.
The check has two complementary aspects:
- Ensure every constructor for a record type needing initialization value-initializes all members and direct bases via a combination of in-class initializers and the member initializer list.
- Value-initialize every non-member instance of a record type needing initialization that lacks a user-provided default constructor, e.g. a POD.
The improvements are...