100 Commits

Author SHA1 Message Date
Matheus Izvekov
91cdd35008
[clang] Improve nested name specifier AST representation (#147835)
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:

![image](https://github.com/user-attachments/assets/700dce98-2cab-4aa8-97d1-b038c0bee831)

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
2025-08-09 05:06:53 -03:00
Yanzuo Liu
4a9eaad9e1
[Clang][AST][NFC] Introduce NamespaceBaseDecl (#149123)
Add `NamespaceBaseDecl` as common base class of `NamespaceDecl` and
`NamespaceAliasDecl`. This simplifies `NestedNameSpecifier` a bit.

Co-authored-by: Matheus Izvekov <mizvekov@gmail.com>
2025-07-18 09:01:47 +08:00
Kazu Hirata
87729bcbb8
[clangd] Migrate away from std::nullopt (NFC) (#145841)
ArrayRef has a constructor that accepts std::nullopt.  This
constructor dates back to the days when we still had llvm::Optional.

Since the use of std::nullopt outside the context of std::optional is
kind of abuse and not intuitive to new comers, I would like to move
away from the constructor and eventually remove it.

This patch replaces std::nullopt with {}.
2025-06-26 08:40:55 -07:00
Matheus Izvekov
761787d425
Reland: [clang] Improved canonicalization for template specialization types (#135414)
This relands https://github.com/llvm/llvm-project/pull/135119, after
fixing crashes seen in LLDB CI reported here:
https://github.com/llvm/llvm-project/pull/135119#issuecomment-2794910840

Fixes https://github.com/llvm/llvm-project/pull/135119

This changes the TemplateArgument representation to hold a flag
indicating whether a tempalte argument of expression type is supposed to
be canonical or not.

This gets one step closer to solving
https://github.com/llvm/llvm-project/issues/92292

This still doesn't try to unique as-written TSTs. While this would
increase the amount of memory savings and make code dealing with the AST
more well-behaved, profiling template argument lists is still too
expensive for this to be worthwhile, at least for now.

This also fixes the context creation of TSTs, so that they don't in some
cases get incorrectly flagged as sugar over their own canonical form.
This is captured in the test expectation change of some AST dumps.

This fixes some places which were unnecessarily canonicalizing these
TSTs.
2025-04-12 14:26:30 -03:00
Dmitry Vasilyev
cbba9600ae
Revert "[clang] Improved canonicalization for template specialization types" (#135354)
Reverts llvm/llvm-project#135119 because of the assert in ASTContext.cpp, line 5619.
See #135352 for details.
2025-04-11 17:55:11 +04:00
Matheus Izvekov
3954d258a5
[clang] Improved canonicalization for template specialization types (#135119)
This changes the TemplateArgument representation to hold a flag
indicating whether a template argument of expression type is supposed to
be canonical or not.

This gets one step closer to solving
https://github.com/llvm/llvm-project/issues/92292

This still doesn't try to unique as-written TSTs. While this would
increase the amount of memory savings and make code dealing with the AST
more well-behaved, profiling template argument lists is still too
expensive for this to be worthwhile, at least for now. Without this
uniquing, this patch stands neutral in terms of performance impact.

This also fixes the context creation of TSTs, so that they don't in some
cases get incorrectly flagged as sugar over their own canonical form.
This is captured in the test expectation change of some AST dumps.

This fixes some places which were unnecessarily canonicalizing these
TSTs.
2025-04-10 14:23:02 -03:00
Matheus Izvekov
dc17429ae6
[clang] improved preservation of template keyword (#133610) 2025-04-01 17:15:18 -03:00
Christian Kandeler
0cfa6e2092
[clangd] Let DefineOutline tweak handle member functions (#95235)
... of class templates.
2024-10-14 11:00:02 +02:00
Youngsuk Kim
f5838cc17f [clang-tools-extra] Don't flush llvm::raw_string_ostream (NFC)
Don't call raw_string_ostream::flush(), which is essentially a no-op.
As specified in the docs, raw_string_ostream is always unbuffered.
( 65b13610a5226b84889b923bae884ba395ad084d for further reference )
2024-09-25 06:12:45 -05:00
Krystian Stasiowski
1202837302
Reapply "[Clang] Unify interface for accessing template arguments as written for class/variable template specializations (#81642)" (#91393)
Reapplies #81642, fixing the crash which occurs when running the lldb test suite.
2024-05-14 16:09:57 -04:00
Adrian Prantl
c6855ab24e Revert "[Clang] Unify interface for accessing template arguments as written for class/variable template specializations (#81642)"
This reverts commit 7115ed0fff027b65fa76fdfae215ed1382ed1473.

This commit broke several LLDB tests.

https://green.lab.llvm.org/job/llvm.org/view/LLDB/job/as-lldb-cmake/3480/
2024-05-07 13:03:14 -07:00
Krystian Stasiowski
7115ed0fff
[Clang] Unify interface for accessing template arguments as written for class/variable template specializations (#81642)
Our current method of storing the template arguments as written for
`(Class/Var)Template(Partial)SpecializationDecl` suffers from a number
of flaws:
- We use `TypeSourceInfo` to store `TemplateArgumentLocs` for class
template/variable template partial/explicit specializations. For
variable template specializations, this is a rather unintuitive hack (as
we store a non-type specialization as a type). Moreover, we don't ever
*need* the type as written -- in almost all cases, we only want the
template arguments (e.g. in tooling use-cases).
- The template arguments as written are stored in a number of redundant
data members. For example, `(Class/Var)TemplatePartialSpecialization`
have their own `ArgsAsWritten` member that stores an
`ASTTemplateArgumentListInfo` (the template arguments).
`VarTemplateSpecializationDecl` has yet _another_ redundant member
"`TemplateArgsInfo`" that also stores an `ASTTemplateArgumentListInfo`.

This patch eliminates all
`(Class/Var)Template(Partial)SpecializationDecl` members which store the
template arguments as written, and turns the `ExplicitInfo` member into
a `llvm::PointerUnion<const ASTTemplateArgumentListInfo*,
ExplicitInstantiationInfo*>` (to avoid unnecessary allocations when the
declaration isn't an explicit instantiation). The template arguments as
written are now accessed via `getTemplateArgsWritten` in all cases.

The "most breaking" change is to AST Matchers, insofar that `hasTypeLoc`
will no longer match class template specializations (since they no
longer store the type as written).
2024-05-07 14:45:52 -04:00
Nour1248
6c74d8083b
[clangd] fix clang-tidy warning (llvm-qualified-auto) (#79617) 2024-01-26 14:21:07 -05:00
Nour1248
feb49bb424
[clangd] Fix typo in function name in AST.cpp (#77504) 2024-01-09 18:58:38 -05:00
Kazu Hirata
d5953e3e30 [clangd] Use StringRef::{starts,ends}_with (NFC)
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.
2023-12-13 23:26:09 -08:00
Jens Massberg
7ec9e20480 [clangd][c++20]Check for correct auto location in DeducedTypeVisitor
In case of a constrained auto the correct location has to chosen.

Differential Revision: https://reviews.llvm.org/D154623
2023-07-10 11:33:42 +02:00
David Goldman
042dd99484 [clangd] Full support for #import insertions
These are still disabled by default, but will work in ObjC code if you
enable the `-import-insertions` flag.

Completion requires ASTSignals to be available; before ASTSignals are
available, we will always use #include. Once they are available, the
behavior varies as follows:

- For source files, use #import if the ObjC language flag is enabled
- For header files:
  - If the ObjC language flag is disabled, use #include
  - If the header file contains any #imports, use #import
  - If the header file references any ObjC decls, use #import
  - Otherwise, use #include

IncludeFixer support is similar, but it does not rely upon ASTSignals,
instead it does the above checks excluding the scan for ObjC symbols.

Differential Revision: https://reviews.llvm.org/D139458
2023-01-09 09:48:30 -05:00
Kazu Hirata
29ffafb575 [clang-tools-extra] Remove remaining uses of llvm::Optional (NFC)
This patch removes the unused "using" declaration and removes #include
"llvm/ADT/Optional.h".

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
2023-01-07 20:34:53 -08:00
Kazu Hirata
f71ffd3b73 [clang-tools-extra] Use std::optional instead of llvm::Optional (NFC)
This patch replaces (llvm::|)Optional< with std::optional<.  I'll post
a separate patch to clean up the "using" declarations, #include
"llvm/ADT/Optional.h", etc.

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
2023-01-07 20:19:42 -08:00
Kazu Hirata
71f557355d [clang-tools-extra] Add #include <optional> (NFC)
This patch adds #include <optional> to those files containing
llvm::Optional<...> or Optional<...>.

I'll post a separate patch to actually replace llvm::Optional with
std::optional.

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
2023-01-07 20:02:20 -08:00
Fangrui Song
b57533d1d5 [clang-tools-extra] llvm::Optional::value => operator*/operator->
std::optional::value() has undesired exception checking semantics and is
unavailable in older Xcode (see _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS). The
call sites block std::optional migration.
2022-12-17 20:03:01 +00:00
Kazu Hirata
76fcfea283 [clang-tools-extra] Don't including None.h (NFC)
These source files no longer use None, so they do not need to include
None.h.

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
2022-12-06 23:22:09 -08:00
Kazu Hirata
7c2b77368f [clang-tools-extra] Use std::nullopt instead of None in comments (NFC)
This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
2022-12-04 17:40:28 -08:00
Kazu Hirata
059a23c0f0 [clang-tools-extra] Use std::nullopt instead of None (NFC)
This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated.  The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
2022-12-03 11:54:50 -08:00
Matheus Izvekov
bcd9ba2b7e
[clang] Track the templated entity in type substitution.
This is a change to how we represent type subsitution in the AST.
Instead of only storing the replaced type, we track the templated
entity we are substituting, plus an index.
We modify MLTAL to track the templated entity at each level.

Otherwise, it's much more expensive to go from the template parameter back
to the templated entity, and not possible to do in some cases, as when
we instantiate outer templates, parameters might still reference the
original entity.

This also allows us to very cheaply lookup the templated entity we saw in
the naming context and find the corresponding argument it was replaced
from, such as for implementing template specialization resugaring.

Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>

Differential Revision: https://reviews.llvm.org/D131858
2022-10-15 22:08:36 +02:00
Sam McCall
e212a4f838 [clangd] Don't print locations of anonymous tags
These are usually not interesting when clangd presents results in
context, and the file paths are noisy.
2022-10-04 21:38:18 +02:00
David Goldman
61ef0ab701 [clangd] Add decl/def support to SymbolDetails
Add an optional declarationRange and definitionRange to SymbolDetails.

This will allow SourceKit-LSP to implement toggling between goto
definition/declaration based on whether the symbol at the cursor
is a definition or declaration.

Differential Revision: https://reviews.llvm.org/D130041
2022-08-01 14:42:19 -04:00
Kazu Hirata
71336d03f1 Use llvm::any_of (NFC) 2022-07-31 15:17:08 -07:00
David Goldman
88a2ac6ad6 [clangd] Improve XRefs support for ObjCMethodDecl
- Correct nameLocation to point to the first selector fragment instead
  of the - or +

- getDefinition now searches through the proper impl decls to find
  the definition of the ObjCMethodDecl if one exists

Differential Revision: https://reviews.llvm.org/D130095
2022-07-26 12:11:26 -04:00
Kazu Hirata
3f3930a451 Remove redundaunt virtual specifiers (NFC)
Identified with tidy-modernize-use-override.
2022-07-25 23:00:59 -07:00
Kadir Cetinkaya
4839929bed
[clangd] Make forwarding parameter detection logic resilient
This could crash when our heuristic picks the wrong function. Make sure
there is enough parameters in the candidate to prevent those crashes.

Also special case copy/move constructors to make the heuristic work in
presence of those.

Fixes https://github.com/llvm/llvm-project/issues/56620

Differential Revision: https://reviews.llvm.org/D130260
2022-07-22 14:37:13 +02:00
Kadir Cetinkaya
b5871dfaf3
[clangd] Refactor forwarding call detection logic
Differential Revision: https://reviews.llvm.org/D130261
2022-07-21 17:58:56 +02:00
Kazu Hirata
5cff5142a8 Use value instead of getValue (NFC) 2022-07-15 20:03:13 -07:00
Fangrui Song
3c849d0aef Modernize Optional::{getValueOr,hasValue} 2022-07-15 01:20:39 -07:00
Kazu Hirata
53daa177f8 [clang, clang-tools-extra] Use has_value instead of hasValue (NFC) 2022-07-12 22:47:41 -07:00
Tobias Ribizel
a638648fef
[clangd] add inlay hints for std::forward-ed parameter packs
This adds special-case treatment for parameter packs in
make_unique-like functions to forward parameter names to inlay hints.
The parameter packs are being resolved recursively by traversing the
function body of forwarding functions looking for expressions matching
the (std::forwarded) parameters expanded from a pack.
The implementation checks whether parameters are being passed by
(rvalue) reference or value and adds reference inlay hints accordingly.
The traversal has a limited recursion stack depth, and recursive calls
like std::make_tuple are cut off to avoid hinting duplicate parameter
names.

Reviewed By: sammccall

Differential Revision: https://reviews.llvm.org/D124690
2022-07-06 22:23:18 +02:00
Andrew Browne
c7689fd552 [Clang] Fix memory leak due to TemplateArgumentListInfo used in AST node.
It looks like the leak is rooted at the allocation here:
1a155ee7de/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp (L3857)

The VarTemplateSpecializationDecl is allocated using placement new which uses the AST structure for ownership: 1a155ee7de/clang/lib/AST/DeclBase.cpp (L99)

The problem is the TemplateArgumentListInfo inside 1a155ee7de/clang/include/clang/AST/DeclTemplate.h (L2721)
This object contains a vector which does not use placement new: 1a155ee7de/clang/include/clang/AST/TemplateBase.h (L564)

Apparently ASTTemplateArgumentListInfo should be used instead 1a155ee7de/clang/include/clang/AST/TemplateBase.h (L575)

https://reviews.llvm.org/D125802#3551305

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D126944
2022-06-08 09:58:25 -07:00
Sam McCall
afa94306a8 [clangd] Add code action to generate a constructor for a C++ class
Differential Revision: https://reviews.llvm.org/D116514
2022-04-06 16:23:50 +02:00
Sam McCall
2da5c5781e [clangd] Add inlay hints for auto-typed parameters with one instantiation.
This takes a similar approach as b9b6938183e, and shares some code.
The code sharing is limited as inlay hints wants to deduce the type of the
variable rather than the type of the `auto` per-se.

It drops support (in both places) for multiple instantiations yielding the same
type, as this is pretty rare and hard to build a nice API around.

Differential Revision: https://reviews.llvm.org/D120258
2022-03-23 17:26:25 +01:00
Sam McCall
4d006520b8 [clangd] Clean up unused includes. NFCI
Add includes where needed to fix build.
Haven't systematically added used headers, so there is still accidental
dependency on transitive includes.
2022-02-26 12:00:16 +01:00
Sam McCall
b9b6938183 [clangd] Treat 'auto' params as deduced if there's a single instantiation.
This makes hover/go-to-definition/expand-auto etc work for auto params in many
common cases.
This includes when a generic lambda is passed to a function accepting
std::function. (The tests don't use this case, it requires a lot of setup).

Note that this doesn't affect the AST of the function body itself, cause its
nodes not to be dependent, improve code completion etc.
(These sort of improvements seem possible, in a similar "if there's a single
instantiation, traverse it instead of the primary template" way).

Fixes https://github.com/clangd/clangd/issues/493
Fixes https://github.com/clangd/clangd/issues/1015

Differential Revision: https://reviews.llvm.org/D119537
2022-02-21 13:24:11 +01:00
Christian Kühnel
c0e3c893aa [NFC][clangd] cleaning up llvm-qualified-auto
This is a cleanup of all llvm-qualified-auto findings.
This patch was created by automatically applying the fixes from
clang-tidy.

Differential Revision: https://reviews.llvm.org/D113898
2022-01-25 13:26:33 +00:00
Sam McCall
055d8090d1 [clangd] Don't index __reserved_names in headers.
Main use of these is in the standard library, where they generally clutter up
the index.

Certain macros are also common, we don't touch indexing of macros in this patch.

Differential Revision: https://reviews.llvm.org/D115301
2022-01-05 16:34:04 +01:00
Sam McCall
7d65cc98f3 [clangd] Guard against null Attrs in the AST 2021-08-13 10:38:52 +02:00
Sam McCall
bb81e7083d [clangd] Add basic support for attributes (selection, hover)
These aren't terribly common, but we currently mishandle them badly.
Not only do we not recogize the attributes themselves, but we often end up
selecting some node other than the parent (because source ranges aren't accurate
in the presence of attributes).

Differential Revision: https://reviews.llvm.org/D89785
2021-08-06 22:49:14 +02:00
Kirill Bobyrev
e0f2d4af03
[clangd] Fix the crash in getQualification
Happens when DestContext is LinkageSpecDecl and hense CurContext happens to be
both not TagDecl and NamespaceDecl.

Minimal reproducer: trigger define outline in

```
namespace ns {
extern "C" {
typedef int foo;
}
foo Fo^o(int id) { return id; }
}
```

Reviewed By: kadircet

Differential Revision: https://reviews.llvm.org/D107047
2021-08-02 09:08:25 +02:00
Kadir Cetinkaya
4581bf31bb
[clangd] Dont index deeply nested symbols
This is fix for some timeouts and OOM problems faced while indexing an
auto-generated file with thousands of nested lambdas.

Differential Revision: https://reviews.llvm.org/D101066
2021-04-27 12:34:56 +02:00
David Goldman
07c5a800dc Improve hover scopes for Objective-C code
- Instead of `AppDelegate::application:didFinishLaunchingWithOptions:` you
will now see `-[AppDelegate application:didFinishLaunchingWithOptions:]`

- Also include categories in the name when printing the scopes, e.g. `Class(Category)` and `-[Class(Category) method]`

Differential Revision: https://reviews.llvm.org/D68590
2021-02-12 10:27:32 -05:00
Sam McCall
7d1b499cae Revert "[clangd] Extract symbol-scope logic out of Quality, add tests. NFC"
On second thought, this can't properly be reused for highlighting.

Consider this example, which Quality wants to consider function-scope,
but highlighting must consider class-scope:

void foo() {
  class X {
    int ^y;
  };
}
2021-01-29 14:59:16 +01:00
Sam McCall
d0817b5f18 [clangd] Extract symbol-scope logic out of Quality, add tests. NFC
This prepares for reuse from the semantic highlighting code.

There's a bit of yak-shaving here:
 - when the enum is moved into the clangd namespace, promote it to a
   scoped enum. This means teaching the decision forest infrastructure
   to deal with scoped enums.
 - AccessibleScope isn't quite the right name: e.g. public class members
   are treated as accessible, but still have class scope. So rename to
   SymbolScope.
 - Rename some QualitySignals members to avoid name conflicts.
   (the string) SymbolScope -> Scope
   (the enum) Scope -> ScopeKind
2021-01-29 14:44:28 +01:00