Commit Graph

13 Commits

Author SHA1 Message Date
Felix Berger cb4c12b611 [clang-tidy] performance-unnecessary-copy-initialization: Create option to exclude container types from triggering the check.
Add string list option of type names analagous to `AllowedTypes` which lets
users specify a list of ExcludedContainerTypes.

Types matching this list will not trigger the check when an expensive variable
is copy initialized from a const accessor method they provide, i.e.:

```
ExcludedContainerTypes = 'ExcludedType'

void foo() {
  ExcludedType<ExpensiveToCopy> Container;
  const ExpensiveToCopy NecessaryCopy = Container.get();
}
```

Even though an expensive to copy variable is copy initialized the check does not
trigger because the container type is excluded.

This is useful for container types that don't own their data, such as view types
where modification of the returned references in other places cannot be reliably
tracked, or const incorrect types.

Differential Revision: https://reviews.llvm.org/D106173

Reviewed-by: ymandel
2021-07-22 16:20:20 -04:00
Felix Berger bdd5da9dec [clang-tidy] performance-unnecessary-copy-initialization: Directly examine the initializing var's initializer.
This fixes false positive cases where a reference is initialized outside of a
block statement and then its initializing variable is modified. Another case is
when the looped over container is modified.

Differential Revision: https://reviews.llvm.org/D103021

Reviewed-by: ymandel
2021-06-18 15:25:17 -04:00
Felix Berger 5dbe3bf4b8 [clang-tidy] performance-unnecessary-copy-initialization: Remove the complete statement when the copied variable is unused.
It is not useful to keep the statement around and can lead to compiler
warnings when -Wall (-Wunused-variable specifically) turned on.

Differential Revision: https://reviews.llvm.org/D102175

Reviewed-by: ymandel
2021-06-09 15:52:48 -04:00
Nathan James bfd99be0fc
[clang-tidy] Update lang restrictions on perf module 2020-06-28 15:18:08 +01:00
Alexander Kornienko 478fc5c83e [clang-tidy] Switch checks to #include "ClangTidyCheck.h"
llvm-svn: 356892
2019-03-25 12:38:26 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
Adam Balogh abd72e9851 [clang-tidy] White List Option for performance-unnecessary-value-param, performance-unnecessary-copy-initialization and performance-for-range-copy
New option added to these three checks to be able to silence false positives on
types that are intentionally passed by value or copied. Such types are e.g.
intrusive reference counting pointer types like llvm::IntrusiveRefCntPtr. The
new option is named WhiteListTypes and can contain a semicolon-separated list of
names of these types. Regular expressions are allowed. Default is empty.

Differential Revision: https://reviews.llvm.org/D52727

llvm-svn: 344340
2018-10-12 13:05:21 +00:00
Felix Berger 98e4019a58 [clang-tidy] UnnecessaryCopyInitialization - Extend to trigger on non-const "this" object argument if it is not modified.
Summary:

Also trigger the check in the following case:

void foo() {
  ExpensiveToCopy Obj;
  const auto UnnecessaryCopy = Obj.constReference();
  Obj.onlyUsedAsConst();
}

i.e. when the object the method is called on is not const but is never
modified.

Reviewers: alexfh, fowles

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D20010

llvm-svn: 271239
2016-05-31 00:25:57 +00:00
Felix Berger 6d3d746ff5 [clang-tidy] - PerformanceUnnecesaryCopyInitialization - only trigger for decl stmts with single VarDecl.
Summary: This fixes bug: https://llvm.org/bugs/show_bug.cgi?id=27325

Reviewers: alexfh

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D19865

llvm-svn: 269389
2016-05-13 02:47:56 +00:00
Haojian Wu 6ccb1dd9f0 Add check for unneeded copies of locals
Summary: Extends the UnnecessaryCopyInitialization to detect copies of local variables and parameters that are unneeded.

Patch by Matt Kulukundis!

Reviewers: alexfh, hokein

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D18149

llvm-svn: 264146
2016-03-23 09:33:07 +00:00
Felix Berger adfdc14832 [clang-tidy] Extend UnnecessaryCopyInitialization check to trigger on non-const copies that can be safely converted to const references.
Summary:
Move code shared between UnnecessaryCopyInitialization and ForRangeCopyCheck into utilities files.
Add more test cases for UnnecessaryCopyInitialization and disable fixes inside of macros.

Reviewers: alexfh

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D17488

llvm-svn: 262781
2016-03-05 21:17:58 +00:00
Alexander Kornienko 1589071288 [clang-tidy] Don't use delegating constructors
llvm-svn: 256637
2015-12-30 11:39:30 +00:00
Alexander Kornienko b959f4c338 [clang-tidy] Add UnnecessaryCopyInitialization check to new "performance" module in ClangTidy
Summary:
The patch adds a new ClangTidy check that detects when expensive-to-copy types are unnecessarily copy initialized from a const reference that has the same or are larger scope than the copy.

It currently only detects this when the copied variable is const qualified. But this will be extended to non const variables if they are only used in a const fashion.

Reviewers: alexfh

Subscribers: cfe-commits

Patch by Felix Berger!

Differential Revision: http://reviews.llvm.org/D15623

llvm-svn: 256632
2015-12-30 10:24:40 +00:00