Commit Graph

27 Commits

Author SHA1 Message Date
Sam McCall 478863ef58 [clangd] Basic IncludeCleaner support for c/c++ standard library
There are some limitations here, so this is behind a flag for now (in addition
to the config setting for the overall feature).

- symbols without exactly one associated header aren't handled right
- no macro support
- referencing std::size_t usually doesn't leave any trace in the AST that the
  alias in std was used, so we associate with stddef.h instead of cstddef.
  (An AST issue not specific to stdlib, but much worse there)

Differential Revision: https://reviews.llvm.org/D114077
2022-01-03 18:19:56 +01:00
Sam McCall af27466c50 Reland "[AST] Add UsingType: a sugar type for types found via UsingDecl"
This reverts commit cc56c66f27.
Fixed a bad assertion, the target of a UsingShadowDecl must not have
*local* qualifiers, but it can be a typedef whose underlying type is qualified.
2021-12-20 18:03:15 +01:00
Sam McCall cc56c66f27 Revert "[AST] Add UsingType: a sugar type for types found via UsingDecl"
This reverts commit e1600db19d.

Breaks sanitizer tests, at least on windows:
https://lab.llvm.org/buildbot/#/builders/127/builds/21592/steps/4/logs/stdio
2021-12-20 17:53:56 +01:00
Sam McCall e1600db19d [AST] Add UsingType: a sugar type for types found via UsingDecl
Currently there's no way to find the UsingDecl that a typeloc found its
underlying type through. Compare to DeclRefExpr::getFoundDecl().

Design decisions:
- a sugar type, as there are many contexts this type of use may appear in
- UsingType is a leaf like TypedefType, the underlying type has no TypeLoc
- not unified with UnresolvedUsingType: a single name is appealing,
  but being sometimes-sugar is often fiddly.
- not unified with TypedefType: the UsingShadowDecl is not a TypedefNameDecl or
  even a TypeDecl, and users think of these differently.
- does not cover other rarer aliases like objc @compatibility_alias,
  in order to be have a concrete API that's easy to understand.
- implicitly desugared by the hasDeclaration ASTMatcher, to avoid
  breaking existing patterns and following the precedent of ElaboratedType.

Scope:
- This does not cover types associated with template names introduced by
  using declarations. A future patch should introduce a sugar TemplateName
  variant for this. (CTAD deduced types fall under this)
- There are enough AST matchers to fix the in-tree clang-tidy tests and
  probably any other matchers, though more may be useful later.

Caveats:
- This changes a fairly common pattern in the AST people may depend on matching.
  Previously, typeLoc(loc(recordType())) matched whether a struct was
  referred to by its original scope or introduced via using-decl.
  Now, the using-decl case is not matched, and needs a separate matcher.
  This is similar to the case of typedefs but nevertheless both adds
  complexity and breaks existing code.

Differential Revision: https://reviews.llvm.org/D114251
2021-12-20 17:15:38 +01:00
Kirill Bobyrev b673bc36ea [clangd] Suppress IncludeCleaner warnings for headers behind pragma keep
D114072 allows filtering out the warnings for headers behind `// IWYU pragma:
keep`. This is the first step towards more useful IWYU pragmas support and
fine-grained control over the IncludeCleaner warnings.

Reviewed By: kadircet

Differential Revision: https://reviews.llvm.org/D115345
2021-12-08 18:07:40 +01:00
Kirill Bobyrev bab7a30ab6 [clangd] IncludeCleaner: Do not require forward declarations of RecordDecls when definition is available
This makes IncludeCleaner more useful in the presense of a large number of
forward declarations. If the definition is already in the Translation Unit and
visible to the Main File, forward declarations have no effect.

The original patch D112707 was split in two: D114864 and this one.

Reviewed By: kadircet

Differential Revision: https://reviews.llvm.org/D114949
2021-12-03 09:36:50 +01:00
Kirill Bobyrev d3a4ef3568 [clangd] IncludeClenaer: Don't mark forward declarations of a class if it's declared in the main file
This will mark more headers that are unrelated to used symbol but contain its
forawrd declaration. E.g. the following are examples of headers forward
declaring `llvm::StringRef`:

- clang/include/clang/Basic/Cuda.h
- llvm/include/llvm/Support/SHA256.h
- llvm/include/llvm/Support/TrigramIndex.h
- llvm/include/llvm/Support/RandomNumberGenerator.
- ... and more (~50 in total)

This patch is a reduced version of D112707 which was controversial.

Reviewed By: kadircet

Differential Revision: https://reviews.llvm.org/D114864
2021-12-02 10:26:08 +01:00
Kirill Bobyrev 34cc210aa8
[clangd] IncludeCleaner: Attribute symbols from non self-contained headers to their parents
When a symbol comes from the non self-contained header, we recursively uplift
the file we consider used to the first includer that has a header guard. We
need to do this while we still have FileIDs because every time a non
self-contained header is included, it gets a new FileID but is later
deduplicated by HeaderID and it's not possible to understand where it was
included from.

Based on D114370.

Reviewed By: sammccall

Differential Revision: https://reviews.llvm.org/D114623
2021-11-26 16:20:48 +01:00
Kirill Bobyrev 59e4a67081
[clangd] Move IncludeCleaner tracer to the actual computation
This way we won't get results with 0 ms for all the users with disabled
IncludeCleaner.
2021-11-25 13:19:01 +01:00
Kirill Bobyrev b5f20372a8
[clangd] IncludeCleaner: Mark possible expr resolutions as used
Fixes: https://github.com/clangd/clangd/issues/934

Reviewed By: sammccall

Differential Revision: https://reviews.llvm.org/D114287
2021-11-22 10:44:24 +01:00
Kirill Bobyrev f47564ea87
[clangd] IncludeCleaner: Skip non self-contained headers
Headers without include guards might have side effects or can be the files we
don't want to consider (e.g. tablegen ".inc" files). Skip them when translating
headers to the HeaderIDs that we will consider as unused.

Reviewed By: sammccall

Differential Revision: https://reviews.llvm.org/D112695
2021-10-29 17:57:31 +02:00
Kirill Bobyrev 32f1029124
[clangd] Track performance of IncludeCleaner
Reviewed By: kadircet

Differential Revision: https://reviews.llvm.org/D112783
2021-10-29 12:59:22 +02:00
Kirill Bobyrev f9201c70ad
[clangd] NFC: Use more idiomatic way of checking for definition 2021-10-28 12:25:12 +02:00
Kirill Bobyrev 56a8aee100 [clangd] NFC: Match function signature in the header and source file 2021-10-28 12:13:18 +02:00
Sam McCall 73453e7ade [clangd] Avoid expensive checks of buffer names in IncludeCleaner
This changes the handling of special buffers (<command-line> etc) that
SourceManager treats as files but FileManager does not.

We now include them in findReferencedFiles() and drop them as part of
translateToHeaderIDs(). This pairs more naturally with the data representations
we're using, and so avoids a bunch of converting between representations for
filtering.

Differential Revision: https://reviews.llvm.org/D112652
2021-10-28 08:00:57 +02:00
Kirill Bobyrev 22079c61a8
[clangd] IncludeCleaner: Do not process locations in built-in files
Doing otherwise leads to crashing. Way to reproduce: open "gmock/gmock.h" in
the LLVM source tree.

Reviewed By: kadircet

Differential Revision: https://reviews.llvm.org/D112608
2021-10-27 19:31:43 +02:00
Kirill Bobyrev 6edc509719 [clangd] NFC: Remove single-line braces in IncludeCleaner 2021-10-27 13:53:30 +02:00
Kirill Bobyrev c4723785c1 [clangd] IncludeCleaner: Don't warn on system headers
This is a temporary hack to disable diagnostics for system headers. As of right
now, IncludeCleaner does not handle the Standard Library correctly and will
report most system headers as unused because very few symbols are defined in
top-level system headers. This will eventually be fixed, but for now we are
aiming for the most conservative approach with as little false-positive
warnings as possible. After the initial prototype and core functionality is
polished, I will turn back to handling the Standard Library as it requires
custom logic.

Reviewed By: sammccall

Differential Revision: https://reviews.llvm.org/D112571
2021-10-27 11:51:08 +02:00
Kirill Bobyrev e3c6090e59 [clangd] IncludeCleaner: Support macros
Collect the macro definition locations for all the macros used in the main
file.

Reviewed By: sammccall

Differential Revision: https://reviews.llvm.org/D112447
2021-10-27 10:30:04 +02:00
Kirill Bobyrev 1c2e249f93
[clangd] IncludeCleaner: don't stop the traversal
I was under the impression that `return false;` in the
RecursiveASTVisitor stops the traversal for the subtree but it appears
that it stops the whole tree traversal, so this change introduces a bug
where `ReferencedLocationCrawler` will not collect any symbols past an
enum.

This is a follow-up on D112209.
2021-10-26 16:08:54 +02:00
Kirill Bobyrev 6d314ee570
[clangd] Add a way to enable IncludeCleaner through config
This is useful for dogfooding the feature and spotting bugs.

Reviewed By: sammccall

Differential Revision: https://reviews.llvm.org/D111870
2021-10-26 12:53:05 +02:00
Kirill Bobyrev c521288ed3
[clangd] IncludeCleaner: Don't consider the definition as usage for function forward declarations
Reviewed By: kadircet

Differential Revision: https://reviews.llvm.org/D111711
2021-10-26 10:37:10 +02:00
Kirill Bobyrev 593814a10c [clangd] IncludeCleaner: Complicated rules for enum usage
Reviewed By: sammccall

Differential Revision: https://reviews.llvm.org/D112209
2021-10-25 22:04:22 +02:00
Kirill Bobyrev 0ce3c7111e
[clangd] IncludeCleaner: Handle macros coming from ScratchBuffer
Reviewed By: sammccall

Differential Revision: https://reviews.llvm.org/D111698
2021-10-14 13:36:37 +02:00
Kirill Bobyrev 6393c21d47 [clangd] IncludeCleaner: Stop crashing when included file is not found 2021-10-08 14:51:11 +02:00
Kirill Bobyrev ebfcd06d42 [clangd] IncludeCleaner: Mark used headers
Follow-up on D105426.

Reviewed By: sammccall

Differential Revision: https://reviews.llvm.org/D108194
2021-10-05 18:08:24 +02:00
Kirill Bobyrev d1ec581ebf
[clangd] IncludeCleaner as a library: Find all references to symbols in the file
This is the first patch in an ongoing attempt of Include Cleaner: unused/missing
headere diagnostics, an IWYU-like functionality implementation for clangd. The
work is split into (mostly) distinct and parallelizable pieces:

- Finding all referenced locations (this patch).
- Finding all referenced locations of macros.
- Building IncludeGraph and marking headers as unused, used and directly used.
- Making use of the introduced library and add an option to use in clangd.

---

* Adding support for standard library headers (possibly through mapping
  genfiles).

Based on https://reviews.llvm.org/D100540.

Reviewed By: sammccall

Differential Revision: https://reviews.llvm.org/D105426
2021-08-18 10:08:35 +02:00