27 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
Matheus Izvekov
dc17429ae6
[clang] improved preservation of template keyword (#133610) 2025-04-01 17:15:18 -03:00
Matheus Izvekov
14f7bd63b9
Reland: [clang] preserve class type sugar when taking pointer to member (#132401)
Original PR: #130537
Originally reverted due to revert of dependent commit. Relanding with no
changes.

This changes the MemberPointerType representation to use a
NestedNameSpecifier instead of a Type to represent the base class.

Since the qualifiers are always parsed as nested names, there was an
impedance mismatch when converting these back and forth into types, and
this led to issues in preserving sugar.

The nested names are indeed a better match for these, as the differences
which a QualType can represent cannot be expressed syntatically, and
they represent the use case more exactly, being either dependent or
referring to a CXXRecord, unqualified.

This patch also makes the MemberPointerType able to represent sugar for
a {up/downcast}cast conversion of the base class, although for now the
underlying type is canonical, as preserving the sugar up to that point
requires further work.

As usual, includes a few drive-by fixes in order to make use of the
improvements.
2025-03-21 13:20:52 -03:00
Matheus Izvekov
5151e6d7fe
Revert "Reland: [clang] preserve class type sugar when taking pointer to member" (#132280)
Reverts llvm/llvm-project#132234

Needs to be reverted due to dependency.

This blocks reverting another PR, see here:
https://github.com/llvm/llvm-project/pull/131965#issuecomment-2741619498
2025-03-20 17:52:48 -03:00
Matheus Izvekov
578f38cd08
Reland: [clang] preserve class type sugar when taking pointer to member (#132234)
Original PR: #130537
Reland after updating lldb too.

This changes the MemberPointerType representation to use a
NestedNameSpecifier instead of a Type to represent the base class.

Since the qualifiers are always parsed as nested names, there was an
impedance mismatch when converting these back and forth into types, and
this led to issues in preserving sugar.

The nested names are indeed a better match for these, as the differences
which a QualType can represent cannot be expressed syntatically, and
they represent the use case more exactly, being either dependent or
referring to a CXXRecord, unqualified.

This patch also makes the MemberPointerType able to represent sugar for
a {up/downcast}cast conversion of the base class, although for now the
underlying type is canonical, as preserving the sugar up to that point
requires further work.

As usual, includes a few drive-by fixes in order to make use of the
improvements.
2025-03-20 15:33:54 -03:00
Matheus Izvekov
6cd62ad08c
Revert "[clang] improve class type sugar preservation in pointers to members" (#132215)
Reverts llvm/llvm-project#130537

This missed updating lldb, which we didn't notice due to lack of
pre-commit CI.
2025-03-20 11:09:25 -03:00
Matheus Izvekov
9b1f905b48
[clang] improve class type sugar preservation in pointers to members (#130537)
This changes the MemberPointerType representation to use a
NestedNameSpecifier instead of a Type to represent the class.

Since the qualifiers are always parsed as nested names, there was an
impedance mismatch when converting these back and forth into types, and
this led to issues in preserving sugar.

The nested names are indeed a better match for these, as the differences
which a QualType can represent cannot be expressed syntactically, and it
also represents the use case more exactly, being either dependent or
referring to a CXXRecord, unqualified.

This patch also makes the MemberPointerType able to represent sugar for
a {up/downcast}cast conversion of the base class, although for now the
underlying type is canonical, as preserving the sugar up to that point
requires further work.

As usual, includes a few drive-by fixes in order to make use of the
improvements, and removing some duplications, for example
CheckBaseClassAccess is deduplicated from across SemaAccess and
SemaCast.
2025-03-20 10:30:24 -03:00
Aaron Ballman
0f1c1be196 [clang] Remove rdar links; NFC
We have a new policy in place making links to private resources
something we try to avoid in source and test files. Normally, we'd
organically switch to the new policy rather than make a sweeping change
across a project. However, Clang is in a somewhat special circumstance
currently: recently, I've had several new contributors run into rdar
links around test code which their patch was changing the behavior of.
This turns out to be a surprisingly bad experience, especially for
newer folks, for a handful of reasons: not understanding what the link
is and feeling intimidated by it, wondering whether their changes are
actually breaking something important to a downstream in some way,
having to hunt down strangers not involved with the patch to impose on
them for help, accidental pressure from asking for potentially private
IP to be made public, etc. Because folks run into these links entirely
by chance (through fixing bugs or working on new features), there's not
really a set of problematic links to focus on -- all of the links have
basically the same potential for causing these problems. As a result,
this is an omnibus patch to remove all such links.

This was not a mechanical change; it was done by manually searching for
rdar, radar, radr, and other variants to find all the various
problematic links. From there, I tried to retain or reword the
surrounding comments so that we would lose as little context as
possible. However, because most links were just a plain link with no
supporting context, the majority of the changes are simple removals.

Differential Review: https://reviews.llvm.org/D158071
2023-08-28 12:13:42 -04:00
Mehdi Amini
e0ac46e69d Revert "Remove rdar links; NFC"
This reverts commit d618f1c3b12effd0c2bdb7d02108d3551f389d3d.
This commit wasn't reviewed ahead of time and significant concerns were
raised immediately after it landed. According to our developer policy
this warrants immediate revert of the commit.

https://llvm.org/docs/DeveloperPolicy.html#patch-reversion-policy

Differential Revision: https://reviews.llvm.org/D155509
2023-07-17 18:08:04 -07:00
Aaron Ballman
d618f1c3b1 Remove rdar links; NFC
This removes links to rdar, which is an internal bug tracker that the
community doesn't have visibility into.

See further discussion at:
https://discourse.llvm.org/t/code-review-reminder-about-links-in-code-commit-messages/71847
2023-07-07 08:41:11 -04:00
Richard Smith
e81daee21b When formatting a C++-only declaration name, enable C++ mode in the formatter's
language options. This is not really ideal -- we should require the right
language options to be passed in, or not require language options to format a
name -- but it fixes a number of *obviously* wrong formattings. Patch by
Olivier Goffart!

llvm-svn: 199778
2014-01-22 00:27:42 +00:00
Alp Toker
6ed7251683 Revert "Don't require -re suffix on -verify directives with regexes."
This patch was submitted to the list for review and didn't receive a LGTM.

(In fact one explicit objection and one query were raised.)

This reverts commit r197295.

llvm-svn: 197299
2013-12-14 01:07:05 +00:00
Hans Wennborg
9b395ef284 Don't require -re suffix on -verify directives with regexes.
Differential Revision: http://llvm-reviews.chandlerc.com/D2392

llvm-svn: 197295
2013-12-14 00:46:53 +00:00
Hans Wennborg
86be54cc80 Tighten test regexes checking for __attribute__((thiscall)) on function types.
The tests were perhaps made too relaxed in r197164 when we switched to the new
MinGW ABI. This makes sure we check explicitly for an optional thiscall
attribute and nothing else.

We should still look into whether we should print these attributes at all in
these cases.

llvm-svn: 197252
2013-12-13 18:34:23 +00:00
Rafael Espindola
3497069784 Switch to the new MingW ABI.
GCC 4.7 changed the MingW ABI. On the clang side this means that methods now
have the thiscall calling convention by default.

llvm-svn: 197164
2013-12-12 16:07:11 +00:00
Kaelyn Uhrain
8aa8da85ca Allow CorrectTypo to replace CXXScopeSpecifiers that refer to classes.
Now that CorrectTypo knows how to correctly search classes for typo
correction candidates, there is no good reason to only replace an
existing CXXScopeSpecifier if it refers to a namespace. While the actual
enablement was a matter of changing a single comparison, the fallout
from enabling the functionality required a lot more code changes
(including my two previous commits).

llvm-svn: 193020
2013-10-19 00:05:00 +00:00
Richard Trieu
553b2b2e5d Modify how the -verify flag works. Currently, the verification string and
diagnostic message are compared.  If either is a substring of the other, then
no error is given.  This gives rise to an unexpected case:

  // expect-error{{candidate function has different number of parameters}}

will match the following error messages from Clang:

  candidate function has different number of parameters (expected 1 but has 2)
  candidate function has different number of parameters

It will also match these other error messages:

  candidate function
  function has different number of parameters
  number of parameters

This patch will change so that the verification string must be a substring of
the diagnostic message before accepting.  Also, all the failing tests from this
change have been corrected.  Some stats from this cleanup:

87 - removed extra spaces around verification strings
70 - wording updates to diagnostics
40 - extra leading or trailing characters (typos, unmatched parens or quotes)
35 - diagnostic level was included (error:, warning:, or note:)
18 - flag name put in the warning (-Wprotocol)

llvm-svn: 146619
2011-12-15 00:38:15 +00:00
John McCall
30909031a7 Enforce access control for conversion operators used in contextual
conversions (rather than just call-arguments).

llvm-svn: 140244
2011-09-21 08:36:56 +00:00
John McCall
9743e8d84e Handle delayed access in local declarations. PR9229.
llvm-svn: 125609
2011-02-15 22:51:53 +00:00
John McCall
25849cab8b Return a declaration to the parser when creating a field in C++ so that
the parser will complete the declarator with a valid decl and thus trigger
delayed diagnostics for it.  It certainly looks like we were intentionally
returning null here, but I couldn't find any good reason for it, and there
wasn't a comment, so farewell to all that.

llvm-svn: 125556
2011-02-15 07:12:36 +00:00
John McCall
796c2a52a9 Treat template parameters as part of the declaration-specifiers for the
purpose of access control.  Fixes PR7644.

I can't actually find anything directly justifying this, but it seems obvious.

llvm-svn: 108521
2010-07-16 08:13:16 +00:00
John McCall
17b61785a3 Test case for r102578.
llvm-svn: 102580
2010-04-29 01:20:45 +00:00
John McCall
80e58cd3e9 Properly switch into the declaring scope of a template when performing
template argument deduction or (more importantly) the final substitution
required by such deduction.  Makes access control magically work in these
cases.

Fixes PR6967.

llvm-svn: 102572
2010-04-29 00:35:03 +00:00
John McCall
3155f573f5 Turn access control on by default in -cc1.
Remove -faccess-control from -cc1; add -fno-access-control.
Make the driver pass -fno-access-control by default.
Update a bunch of tests to be correct under access control.

llvm-svn: 100880
2010-04-09 19:03:51 +00:00
John McCall
5b0829a321 Improve access control diagnostics. Perform access control on member-pointer
conversions.  Fix an access-control bug where privileges were not considered
at intermediate points along the inheritance path.  Prepare for friends.

llvm-svn: 95775
2010-02-10 09:31:12 +00:00
John McCall
760af170ff Access checking for implicit user-defined conversions.
llvm-svn: 94971
2010-02-01 03:16:54 +00:00
John McCall
86121519ca Implement access-check delays for out-of-line member definitions
using the same framework we use for deprecation warnings.

llvm-svn: 94659
2010-01-27 03:50:35 +00:00