This is a major change on how we represent nested name qualifications in
the AST.
* The nested name specifier itself and how it's stored is changed. The
prefixes for types are handled within the type hierarchy, which makes
canonicalization for them super cheap, no memory allocation required.
Also translating a type into nested name specifier form becomes a no-op.
An identifier is stored as a DependentNameType. The nested name
specifier gains a lightweight handle class, to be used instead of
passing around pointers, which is similar to what is implemented for
TemplateName. There is still one free bit available, and this handle can
be used within a PointerUnion and PointerIntPair, which should keep
bit-packing aficionados happy.
* The ElaboratedType node is removed, all type nodes in which it could
previously apply to can now store the elaborated keyword and name
qualifier, tail allocating when present.
* TagTypes can now point to the exact declaration found when producing
these, as opposed to the previous situation of there only existing one
TagType per entity. This increases the amount of type sugar retained,
and can have several applications, for example in tracking module
ownership, and other tools which care about source file origins, such as
IWYU. These TagTypes are lazily allocated, in order to limit the
increase in AST size.
This patch offers a great performance benefit.
It greatly improves compilation time for
[stdexec](https://github.com/NVIDIA/stdexec). For one datapoint, for
`test_on2.cpp` in that project, which is the slowest compiling test,
this patch improves `-c` compilation time by about 7.2%, with the
`-fsyntax-only` improvement being at ~12%.
This has great results on compile-time-tracker as well:
This patch also further enables other optimziations in the future, and
will reduce the performance impact of template specialization resugaring
when that lands.
It has some other miscelaneous drive-by fixes.
About the review: Yes the patch is huge, sorry about that. Part of the
reason is that I started by the nested name specifier part, before the
ElaboratedType part, but that had a huge performance downside, as
ElaboratedType is a big performance hog. I didn't have the steam to go
back and change the patch after the fact.
There is also a lot of internal API changes, and it made sense to remove
ElaboratedType in one go, versus removing it from one type at a time, as
that would present much more churn to the users. Also, the nested name
specifier having a different API avoids missing changes related to how
prefixes work now, which could make existing code compile but not work.
How to review: The important changes are all in
`clang/include/clang/AST` and `clang/lib/AST`, with also important
changes in `clang/lib/Sema/TreeTransform.h`.
The rest and bulk of the changes are mostly consequences of the changes
in API.
PS: TagType::getDecl is renamed to `getOriginalDecl` in this patch, just
for easier to rebasing. I plan to rename it back after this lands.
Fixes#136624
Fixes https://github.com/llvm/llvm-project/issues/43179
Fixes https://github.com/llvm/llvm-project/issues/68670
Fixes https://github.com/llvm/llvm-project/issues/92757
Added `.clang-tidy` config as discussed in
[RFC](https://discourse.llvm.org/t/rfc-create-hardened-clang-tidy-config-for-clang-tidy-directory/87247).
Added `bugprone`, `readability`, `modernize`, `performance` checks that
didn't create many warnings.
Fixed minor warnings to make `/clang-tidy` directory complaint with
`clang-tidy-20`.
Disabled checks will be enabled in future PRs after fixing their
warnings.
These are identified by misc-include-cleaner. I've filtered out those
that break builds. Also, I'm staying away from llvm-config.h,
config.h, and Compiler.h, which likely cause platform- or
compiler-specific build failures.
The code sanitizer is failing with this error: `Execution cannot reach
this statement.`
The execution code path would early exit at line 928 if `(Lil && Ril) =
true`.
This patch addresses situations when misc-redundant-expression checker
provides excessive diagnostics for situations with different macros
having the same value. In particular it addresses situations described
in the initial report of
https://github.com/llvm/llvm-project/issues/118885 are addressed. The
situations which are popped inside discussion like if (A + B == B + A)
for macros are not properly addressed by this patch.
Those changes are also mentioned in Release Notes.
---------
Co-authored-by: Vladislav Aranov <vladislav.aranov@ericsson.com>
Co-authored-by: EugeneZelenko <eugene.zelenko@gmail.com>
This change removes the alpha.core.IdenticalExpr static analysis checker
since it's checks are present in the clang-tidy checks
misc-redundant-expression and bugprone-branch-clone. This check was
implemented as a static analysis check using AST matching, and since
alpha and duplicated in 2 clang-tidy checks may be removed.
Co-authored-by: Vince Bridgers <vince.a.bridgers@ericsson.com>
This patch replaces uses of StringRef::{starts,ends}with with
StringRef::{starts,ends}_with for consistency with
std::{string,string_view}::{starts,ends}_with in C++20.
I'm planning to deprecate and eventually remove
StringRef::{starts,ends}with.
Modify check to ignore any parent typeLoc and
other unevaluated context.
Fixes: #35857
Reviewed By: carlosgalvezp
Differential Revision: https://reviews.llvm.org/D157374
Fixed issue with the comparison of UnaryExprOrTypeTraitExpr
objects in which only the argument type was checked, without
considering the kind of expression. This led to false positives when
using sizeof(x) and alignof(x) expressions, as only the
comparison x = x was performed without checking if sizeof
was equal to alignof.
Fixes: https://github.com/llvm/llvm-project/issues/63096
Reviewed By: Izaron
Differential Revision: https://reviews.llvm.org/D152713
Run clang-tidy on all source files under `clang-tools-extra/clang-tidy`
with `-header-filter=clang-tidy.*` and make suggested corrections.
Differential Revision: https://reviews.llvm.org/D112864
Update clang-tools-extra, clang/tools, clang/unittests to migrate from
`SourceManager::getBuffer`, which returns an always dereferenceable
`MemoryBuffer*`, to `getBufferOrNone` or `getBufferOrFake`, both of
which return a `MemoryBufferRef`, depending on whether the call site was
checking for validity of the buffer. No functionality change intended.
Differential Revision: https://reviews.llvm.org/D89416
readability-redundant-expression now detects expressions where a logical
or bitwise operator had equivalent LHS and RHS where the equivalent
operands were separated by more operands.
Do not warn for redundant conditional expressions when the true and false
branches are expanded from different macros even when they are defined by
one another.
Patch by Daniel Krupp.
The static analyzer is warning about potential null dereferences, but in these cases we should be able to use castAs<> directly and if not assert will fire for us.
llvm-svn: 375102
Summary: It was trying to pass a dependent expression into constant evaluator.
Reviewers: ilya-biryukov
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D63188
llvm-svn: 363133
Summary:
The assertion "isIntegerConstantExpr" is triggered in the
isIntegerConstantExpr(), we should not call it if the expression is value
dependent.
Reviewers: gribozavr
Subscribers: xazax.hun, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D62947
llvm-svn: 362701
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
Examples:
* Always evaluates to 0:
```
int X;
if (0 & X) return;
```
* Always evaluates to ~0:
```
int Y;
if (Y | ~0) return;
```
* The symbol is unmodified:
```
int Z;
Z &= ~0;
```
Patch by: Lilla Barancsuk!
Differential Revision: https://reviews.llvm.org/D39285
llvm-svn: 321168
Redundant Expression Checker is updated to be able to detect expressions that
contain macros. Also, other small details are modified to improve the current
implementation.
The improvements in detail are as follows:
* Binary and ternary operator expressions containing two constants, with at
least one of them from a macro, are detected and tested for redundancy.
Macro expressions are treated somewhat differently from other expressions,
because the particular values of macros can vary across builds.
They can be considered correct and intentional, even if macro values equal,
produce ranges that exclude each other or fully overlap, etc.
* The code structure is slightly modified: typos are corrected,
comments are added and some functions are renamed to improve comprehensibility,
both in the checker and the test file. A few test cases are moved to another
function.
* The checker is now able to detect redundant CXXFunctionalCastExprs as well.
A corresponding test case is added.
Patch by: Lilla Barancsuk!
Differential Revision: https://reviews.llvm.org/D38688
llvm-svn: 317570
Catch trivially true statements of the form a != 1 || a != 3. Statements like
these are likely errors. They are particularly easy to miss when handling enums:
enum State {
RUNNING,
STOPPED,
STARTING,
ENDING
}
...
if (state != RUNNING || state != STARTING)
...
Patch by Blaise Watson!
Differential revision: https://reviews.llvm.org/D29858
llvm-svn: 298607
Summary: This patch is adding support to recognize more complex redundant expressions.
Reviewers: alexfh
Subscribers: aaron.ballman, cfe-commits, chrisha
Differential Revision: http://reviews.llvm.org/D21392
llvm-svn: 274731
Summary:
This patch is adding support for conditional expression and overloaded operators.
To decrease false-positive, this patch is adding a list of banned macro names that
has multiple variant with same integer value.
Also fixed support for template instantiation and added an unittest.
Reviewers: alexfh
Subscribers: klimek, Sarcasm, cfe-commits
Differential Revision: http://reviews.llvm.org/D19703
llvm-svn: 269275
Summary:
This checker finds redundant expression on both side of a binary operator.
The current implementation provide a function to check whether expressions
are equivalent. This implementation is able to recognize the common
subset encounter in C++ program. Side-effects like "x++" are not considered
to be equivalent.
There are many False Positives related to macros and to floating point
computations (detecting NaN). The checker is ignoring these cases.
Example:
```
if( !dst || dst->depth != desired_depth ||
dst->nChannels != desired_num_channels ||
dst_size.width != src_size.width ||
dst_size.height != dst_size.height ) <<--- bug
{
```
Reviewers: alexfh
Subscribers: danielmarjamaki, fahlgren, jordan_rose, zaks.anna, Eugene.Zelenko, cfe-commits
Differential Revision: http://reviews.llvm.org/D19451
llvm-svn: 267574
