Currently, there is basically just one clang-tidy check to impose
some sanity limits on functions - `clang-tidy-readability-function-size`.
It is nice, allows to limit line count, total number of statements,
number of branches, number of function parameters (not counting
implicit `this`), nesting level.
However, those are simple generic metrics. It is still trivially possible
to write a function, which does not violate any of these metrics,
yet is still rather unreadable.
Thus, some additional, slightly more complicated metric is needed.
There is a well-known [[ https://en.wikipedia.org/wiki/Cyclomatic_complexity | Cyclomatic complexity]], but certainly has its downsides.
And there is a [[ https://www.sonarsource.com/docs/CognitiveComplexity.pdf | COGNITIVE COMPLEXITY by SonarSource ]], which is available for opensource on https://sonarcloud.io/.
This check checks function Cognitive Complexity metric, and flags
the functions with Cognitive Complexity exceeding the configured limit.
The default limit is `25`, same as in 'upstream'.
The metric is implemented as per [[ https://www.sonarsource.com/docs/CognitiveComplexity.pdf | COGNITIVE COMPLEXITY by SonarSource ]] specification version 1.2 (19 April 2017), with two notable exceptions:
* `preprocessor conditionals` (`#ifdef`, `#if`, `#elif`, `#else`,
`#endif`) are not accounted for.
Could be done. Currently, upstream does not account for them either.
* `each method in a recursion cycle` is not accounted for.
It can't be fully implemented, because cross-translational-unit
analysis would be needed, which is not possible in clang-tidy.
Thus, at least right now, i completely avoided implementing it.
There are some further possible improvements:
* Are GNU statement expressions (`BinaryConditionalOperator`) really free?
They should probably cause nesting level increase,
and complexity level increase when they are nested within eachother.
* Microsoft SEH support
* ???
Reviewed By: aaron.ballman, JonasToth, lattner
Differential Revision: https://reviews.llvm.org/D36836
Some projects do not use the TEMP_FAILURE_RETRY macro but define their
own one, as not to depend on glibc / Bionic details. By allowing the
user to override the list of macros, these projects can also benefit
from this check.
Differential Revision: https://reviews.llvm.org/D83144
Finds member initializations in the constructor body which can be placed
into the initialization list instead. This does not only improves the
readability of the code but also affects positively its performance.
Class-member assignments inside a control statement or following the
first control statement are ignored.
Differential Revision: https://reviews.llvm.org/D71199
//AST Matcher// `hasBody` is a polymorphic matcher that behaves
differently for loop statements and function declarations. The main
difference is the for functions declarations it does not only call
`FunctionDecl::getBody()` but first checks whether the declaration in
question is that specific declaration which has the body by calling
`FunctionDecl::doesThisDeclarationHaveABody()`. This is achieved by
specialization of the template `GetBodyMatcher`. Unfortunately template
specializations do not catch the descendants of the class for which the
template is specialized. Therefore it does not work correcly for the
descendants of `FunctionDecl`, such as `CXXMethodDecl`,
`CXXConstructorDecl`, `CXXDestructorDecl` etc. This patch fixes this
issue by using a template metaprogram.
The patch also introduces a new matcher `hasAnyBody` which matches
declarations which have a body present in the AST but not necessarily
belonging to that particular declaration.
Differential Revision: https://reviews.llvm.org/D87527
Placement new operators on non-object types cause crash in
`bugprone-misplaced-pointer-arithmetic-in-alloc`. This patch fixes this
issue.
Differential Revision: https://reviews.llvm.org/D87683
Instead of using CLANG_ENABLE_STATIC_ANALYZER for use of the
static analyzer in both clang and clang-tidy, add a second
toggle CLANG_TIDY_ENABLE_STATIC_ANALYZER.
This allows enabling the static analyzer in clang-tidy while
disabling it in clang.
Differential Revison: https://reviews.llvm.org/D87118
The altera struct pack align lint check finds structs that are inefficiently
packed or aligned and recommends packing/aligning of the structs using the
packed and aligned attributes as needed in a warning.
This change groups
* Rename: `ignoreParenBaseCasts` -> `IgnoreParenBaseCasts` for uniformity
* Rename: `IgnoreConversionOperator` -> `IgnoreConversionOperatorSingleStep` for uniformity
* Inline `IgnoreNoopCastsSingleStep` into a lambda inside `IgnoreNoopCasts`
* Refactor `IgnoreUnlessSpelledInSource` to make adequate use of `IgnoreExprNodes`
Differential Revision: https://reviews.llvm.org/D86880
Checking the same condition again in a nested `if` usually make no sense,
except if the value of the expression could have been changed between
the two checks. Although compilers may optimize this out, such code is
suspicious: the programmer may have meant to check something else.
Therefore it is worth to find such places in the code and notify the
user about the problem.
This patch implements a basic check for this problem. Currently it
only detects redundant conditions where the condition is a variable of
integral type. It also detects the possible bug if the variable is in an
//or// or //and// logical expression in the inner if and/or the variable
is in an //and// logical expression in the outer if statement. Negated
cases are not handled yet.
Differential Revision: https://reviews.llvm.org/D81272
Finds member initializations in the constructor body which can
be placed to the member initializers of the constructor instead.
This does not only improves the readability of the code but also
affects positively its performance. Class-member assignments
inside a control statement or following the first control
statement are ignored.
Differential Revision: https://reviews.llvm.org/D71199
The action='store_true' option of argparse.add_argument implicitly
generates a default value of False if the argument is not specified.
Thus, the allow_enabling_alpha_checkers argument of
get_tidy_invocation is never None.
The Abseil-NoInternalDependenciesCheck currently mistakenly triggers on any usage of internal helpers even if it is within absl/status.
Differential Revision: https://reviews.llvm.org/D85843
Skeleton checks generated by clang-tidy add_check.py cause assertions to fail when run over anonymous functions(lambda functions). This patch introduces an additional check to verify that the target function is not anonymous before calling getName().
The code snippet from the [[ https://clang.llvm.org/extra/clang-tidy/Contributing.html | clang-tidy tutorial ]]is also updated.
Reviewed By: alexfh, DavidTruby
Differential Revision: https://reviews.llvm.org/D85218
Currently, changes to includes are applied to an entire rule. However,
include changes may be specific to particular edits within a rule (for example,
they may apply to one file but not another). Also, include changes may need to
carry metadata, just like other changes. So, we make include changes first-class
edits.
Reviewed By: tdl-g
Differential Revision: https://reviews.llvm.org/D85734
Inside clangd, clang-tidy checks don't see preprocessor events in the preamble.
This leads to `Token::PtrData == nullptr` for tokens that the macro is defined to.
E.g. `#define SIGTERM 15`:
- Token::Kind == tok::numeric_constant (Token::isLiteral() == true)
- Token::UintData == 2
- Token::PtrData == nullptr
As the result of this, bugprone-bad-signal-to-kill-thread check crashes at null-dereference inside clangd.
Reviewed By: hokein
Differential Revision: https://reviews.llvm.org/D85417
When checking for the style of a decl that isn't in the main file, the check will now search for the configuration that the included files uses to gather the style for its decls.
This can be useful to silence warnings in header files that follow a different naming convention without using header-filter to silence all warnings(even from other checks) in the header file.
Reviewed By: aaron.ballman, gribozavr2
Differential Revision: https://reviews.llvm.org/D84814
These methods abstract away Error handling when trying to read options that can't be parsed by logging the error automatically and returning None.
Reviewed By: gribozavr2
Differential Revision: https://reviews.llvm.org/D84812
When building with LLVM8.0 on RHEL7.8 I got failures like this
after commit 45a720a864320bbbe:
/app/llvm/8.0/bin/../lib/gcc/x86_64-unknown-linux-gnu/
5.4.0/../../../../include/c++/5.4.0/ext/new_allocator.h:120:23:
error: no matching constructor for initialization of
'std::pair<std::__cxx11::basic_string<char>,
std::__cxx11::basic_string<char> >'
{ ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
...
../../clang-tools-extra/clang-tidy/ClangTidyOptions.cpp:73:15:
note: in instantiation of function template specialization
'std::vector<std::pair<std::__cxx11::basic_string<char>,
std::__cxx11::basic_string<char> >,
std::allocator<std::pair<std::__cxx11::basic_string<char>,
std::__cxx11::basic_string<char> > > >::emplace_back<llvm::StringRef,
const std::__cxx11::basic_string<char> &>' requested here
Options.emplace_back(KeyValue.getKey(), KeyValue.getValue().Value);
This is an attempt to avoid such build problems.
Ordering of options isn't important so an `llvm::StringMap` is a much better container for this purpose.
Reviewed By: gribozavr2
Differential Revision: https://reviews.llvm.org/D84868
Handle insertion fix-its when removing incompatible errors by introducting a new EventType `ET_Insert`
This has lower prioirty than End events, but higher than begin.
Idea being If an insert is at the same place as a begin event, the insert should be processed first to reduce unnecessary conflicts.
Likewise if its at the same place as an end event, process the end event first for the same reason.
This also fixes https://bugs.llvm.org/show_bug.cgi?id=46511.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D82898
Not a bug that is ever likely to materialise, but still worth fixing
Reviewed By: DmitryPolukhin
Differential Revision: https://reviews.llvm.org/D84850
The previous fix for this, https://reviews.llvm.org/D76761, Passed test cases but failed in the real world as std::string has a non trivial destructor so creates a CXXBindTemporaryExpr.
This handles that shortfall and updates the test case std::basic_string implementation to use a non trivial destructor to reflect real world behaviour.
Reviewed By: gribozavr2
Differential Revision: https://reviews.llvm.org/D84831
Alexander Kornienko