This simplifies the code by removing the manual optimization for size ==
1, and also gives us an optimization for other small sizes.
Accept a `llvm::SmallVector` by value for the constructor and move it
into the destination, rather than accepting `ArrayRef` that we copy
from. This also lets us not have to construct a reference to the
elements of a `std::initializer_list`, which requires reading the
implementation of the constructor to know whether it's safe.
Also explicitly document that the constructor requires the input indexes
to have a size of at least 1.
This reverts commit
54a4da9df6.
MSVC supports an extension allowing to delete an array of objects via
pointer whose static type doesn't match its dynamic type. This is done
via generation of special destructors - vector deleting destructors.
MSVC's virtual tables always contain a pointer to the vector deleting
destructor for classes with virtual destructors, so not having this
extension implemented causes clang to generate code that is not
compatible with the code generated by MSVC, because clang always puts a
pointer to a scalar deleting destructor to the vtable. As a bonus the
deletion of an array of polymorphic object will work just like it does
with MSVC - no memory leaks and correct destructors are called.
This patch will cause clang to emit code that is compatible with code
produced by MSVC but not compatible with code produced with clang of
older versions, so the new behavior can be disabled via passing
-fclang-abi-compat=21 (or lower).
Fixes https://github.com/llvm/llvm-project/issues/19772
MSVC supports an extension allowing to delete an array of objects via
pointer whose static type doesn't match its dynamic type. This is done
via generation of special destructors - vector deleting destructors.
MSVC's virtual tables always contain a pointer to the vector deleting
destructor for classes with virtual destructors, so not having this
extension implemented causes clang to generate code that is not
compatible with the code generated by MSVC, because clang always puts a
pointer to a scalar deleting destructor to the vtable. As a bonus the
deletion of an array of polymorphic object will work just like it does
with MSVC - no memory leaks and correct destructors are called.
This patch will cause clang to emit code that is compatible with code
produced by MSVC but not compatible with code produced with clang of
older versions, so the new behavior can be disabled via passing
-fclang-abi-compat=21 (or lower).
This is yet another attempt to land vector deleting destructors support
originally implemented by
https://github.com/llvm/llvm-project/pull/133451.
This PR contains fixes for issues reported in the original PR as well as
fixes for issues related to operator delete[] search reported in several
issues like
https://github.com/llvm/llvm-project/pull/133950#issuecomment-2787510484https://github.com/llvm/llvm-project/issues/134265
Fixes https://github.com/llvm/llvm-project/issues/19772
This rename was made as part of
https://github.com/llvm/llvm-project/pull/147835 in order to ease
rebasing the PR, and give a nice window for other patches to get rebased
as well.
It has been a while already, so lets go ahead and rename it back.
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
Finding operator delete[] is still problematic, without it the extension
is a security hazard, so reverting until the problem with operator
delete[] is figured out.
This reverts the following PRs:
Reland [MS][clang] Add support for vector deleting destructors (llvm#133451)
[MS][clang] Make sure vector deleting dtor calls correct operator delete (llvm#133950)
[MS][clang] Fix crash on deletion of array of pointers (llvm#134088)
[clang] Do not diagnose unused deleted operator delete[] (llvm#134357)
[MS][clang] Error about ambiguous operator delete[] only when required (llvm#135041)
Whereas it is UB in terms of the standard to delete an array of objects
via pointer whose static type doesn't match its dynamic type, MSVC
supports an extension allowing to do it.
Aside from array deletion not working correctly in the mentioned case,
currently not having this extension implemented causes clang to generate
code that is not compatible with the code generated by MSVC, because
clang always puts scalar deleting destructor to the vftable. This PR
aims to resolve these problems.
It was reverted due to link time errors in chromium with sanitizer
coverage enabled,
which is fixed by https://github.com/llvm/llvm-project/pull/131929 .
The second commit of this PR also contains a fix for a runtime failure
in chromium reported
in
https://github.com/llvm/llvm-project/pull/126240#issuecomment-2730216384
.
Fixes https://github.com/llvm/llvm-project/issues/19772
This caused link errors when building with sancov. See comment on the PR.
> Whereas it is UB in terms of the standard to delete an array of objects
> via pointer whose static type doesn't match its dynamic type, MSVC
> supports an extension allowing to do it.
> Aside from array deletion not working correctly in the mentioned case,
> currently not having this extension implemented causes clang to generate
> code that is not compatible with the code generated by MSVC, because
> clang always puts scalar deleting destructor to the vftable. This PR
> aims to resolve these problems.
>
> Fixes https://github.com/llvm/llvm-project/issues/19772
This reverts commit d6942d54f677000cf713d2b0eba57b641452beb4.
Whereas it is UB in terms of the standard to delete an array of objects
via pointer whose static type doesn't match its dynamic type, MSVC
supports an extension allowing to do it.
Aside from array deletion not working correctly in the mentioned case,
currently not having this extension implemented causes clang to generate
code that is not compatible with the code generated by MSVC, because
clang always puts scalar deleting destructor to the vftable. This PR
aims to resolve these problems.
Fixes https://github.com/llvm/llvm-project/issues/19772
Virtual function pointer entries in v-tables are signed with address
discrimination in addition to declaration-based discrimination, where an
integer discriminator the string hash (see
`ptrauth_string_discriminator`) of the mangled name of the overridden
method. This notably provides diversity based on the full signature of
the overridden method, including the method name and parameter types.
This patch introduces ItaniumVTableContext logic to find the original
declaration of the overridden method.
On AArch64, these pointers are signed using the `IA` key (the
process-independent code key.)
V-table pointers can be signed with either no discrimination, or a
similar scheme using address and decl-based discrimination. In this
case, the integer discriminator is the string hash of the mangled
v-table identifier of the class that originally introduced the vtable
pointer.
On AArch64, these pointers are signed using the `DA` key (the
process-independent data key.)
Not using discrimination allows attackers to simply copy valid v-table
pointers from one object to another. However, using a uniform
discriminator of 0 does have positive performance and code-size
implications on AArch64, and diversity for the most important v-table
access pattern (virtual dispatch) is already better assured by the
signing schemas used on the virtual functions. It is also known that
some code in practice copies objects containing v-tables with `memcpy`,
and while this is not permitted formally, it is something that may be
invasive to eliminate.
This is controlled by:
```
-fptrauth-vtable-pointer-type-discrimination
-fptrauth-vtable-pointer-address-discrimination
```
In addition, this provides fine-grained controls in the
ptrauth_vtable_pointer attribute, which allows overriding the default
ptrauth schema for vtable pointers on a given class hierarchy, e.g.:
```
[[clang::ptrauth_vtable_pointer(no_authentication, no_address_discrimination,
no_extra_discrimination)]]
[[clang::ptrauth_vtable_pointer(default_key, default_address_discrimination,
custom_discrimination, 0xf00d)]]
```
The override is then mangled as a parametrized vendor extension:
```
"__vtptrauth" I
<key>
<addressDiscriminated>
<extraDiscriminator>
E
```
To support this attribute, this patch adds a small extension to the
attribute-emitter tablegen backend.
Note that there are known areas where signing is either missing
altogether or can be strengthened. Some will be addressed in later
changes (e.g., member function pointers, some RTTI).
`dynamic_cast` in particular is handled by emitting an artificial
v-table pointer load (in a way that always authenticates it) before the
runtime call itself, as the runtime doesn't have enough information
today to properly authenticate it. Instead, the runtime is currently
expected to strip the v-table pointer.
---------
Co-authored-by: John McCall <rjmccall@apple.com>
Co-authored-by: Ahmed Bougacha <ahmed@bougacha.org>
This patch converts `PredefinedExpr::IdentKind` into a scoped enum in namespace scope, making it eligible for forward declaring. This is useful in certain contexts, such as `preferred_type` annotations on bit-fields.
This reverts commit 070493ddbd9473499d6f00ca62bc6aa92808ed79 (and
relands the original change). This removes a test run that makes an
assumption of RTTI being on by default for a given target.
For programs that don't use RTTI, the rtti component is just replaced with a
zero. This way, vtables that don't use RTTI can still cooperate with vtables
that use RTTI since offset calculations on the ABI level would still work.
However, if throughout your whole program you don't use RTTI at all (such as
the embedded case), then this is just an unused pointer-sized component that's
wasting space. This adds an experimental option for removing the RTTI component
from the vtable.
Some notes:
- This is only allowed when RTTI is disabled, so we don't have to worry about
things like `typeid` or `dynamic_cast`.
- This is a "use at your own risk" since, similar to relative vtables, everything
must be compiled with this since it's an ABI breakage. That is, a program compiled
with this is not guaranteed to work with a program compiled without this, even
if RTTI is disabled for both programs.
Note that this is a completely different ABI flavor orthogonal to the
relative-vtables ABI. That is, they can be enabled/disabled independently.
Differential Revision: https://reviews.llvm.org/D152405
In sorting elements can compare with themselves and sometimes assert
further down the line was triggered.
The changes are somewhat NFC, which explains the lack of test coverage.
libc++ has a debug mode that enables extra precondition checking. When
Clang is built with libc++ in that special mode, a few of Clang's tests
would fail with the libc++ assertion because Clang was not honoring the
preconditions for std::stable_sort. However, Clang would not hit the
precondition failure with any release mode STL, so the changes have no
impact on users beyond ones in this very special circumstance.
Differential Revision: https://reviews.llvm.org/D155809
Mixing LLVM and Clang address spaces can result in subtle bugs, and there
is no need for this hook to use the LLVM IR level address spaces.
Most of this change is just replacing zero with LangAS::Default,
but it also allows us to remove a few calls to getTargetAddressSpace().
This also removes a stale comment+workaround in
CGDebugInfo::CreatePointerLikeType(): ASTContext::getTypeSize() does
return the expected size for ReferenceType (and handles address spaces).
Differential Revision: https://reviews.llvm.org/D138295
Under the hood this prints the same as `QualType::getAsString()` but cuts out the middle-man when that string is sent to another raw_ostream.
Also cleaned up all the call sites where this occurs.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D123926
For the Itanium C++ ABI, this implements the rule added in
https://github.com/itanium-cxx-abi/cxx-abi/pull/83
For the MS C++ ABI, this implements the direction that seemed most
plausible based on personal correspondence with MSVC developers, but is
subject to change as they decide their ABI rule.
This patch contains all of the clang changes from D72959.
- Generalize the relative vtables ABI such that it can be used by other targets.
- Add an enum VTableComponentLayout which controls whether components in the
vtable should be pointers to other structs or relative offsets to those structs.
Other ABIs can change this enum to restructure how components in the vtable
are laid out/accessed.
- Add methods to ConstantInitBuilder for inserting relative offsets to a
specified position in the aggregate being constructed.
- Fix failing tests under new PM and ASan and MSan issues.
See D72959 for background info.
Differential Revision: https://reviews.llvm.org/D77592
This reverts commit 2e009dbcb3e373a59e6e84dce6d51ae8a29f60a5.
Reverting since there were some test failures on buildbots that used the
new pass manager. ASan and MSan are also finding some bugs in this that
I'll need to address.
This patch contains all of the clang changes from D72959.
- Generalize the relative vtables ABI such that it can be used by other targets.
- Add an enum VTableComponentLayout which controls whether components in the
vtable should be pointers to other structs or relative offsets to those structs.
Other ABIs can change this enum to restructure how components in the vtable
are laid out/accessed.
- Add methods to ConstantInitBuilder for inserting relative offsets to a
specified position in the aggregate being constructed.
See D72959 for background info.
Differential Revision: https://reviews.llvm.org/D77592
Summary:
We previously listed first declared members, then implicit operator=,
then implicit operator==, then implicit destructors. Per discussion on
https://github.com/itanium-cxx-abi/cxx-abi/issues/88, put the implicit
equality comparison operators at the very end, after all special member
functions.
This reinstates add2b7e44ada46f30715b5c48823a9e9e317e0c3, reverted in
commit 89e43f04ba87a0da6e94863db149669c7536486b, with a fix for 32-bit
targets.
Reviewers: rjmccall
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D72897
Summary:
We previously listed first declared members, then implicit operator=,
then implicit operator==, then implicit destructors. Per discussion on
https://github.com/itanium-cxx-abi/cxx-abi/issues/88, put the implicit
equality comparison operators at the very end, after all special member
functions.
Reviewers: rjmccall
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D72897
Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.
Differential revision: https://reviews.llvm.org/D66259
llvm-svn: 368942
As noted in https://bugs.llvm.org/show_bug.cgi?id=36651, the specialization for
isPodLike<std::pair<...>> did not match the expectation of
std::is_trivially_copyable which makes the memcpy optimization invalid.
This patch renames the llvm::isPodLike trait into llvm::is_trivially_copyable.
Unfortunately std::is_trivially_copyable is not portable across compiler / STL
versions. So a portable version is provided too.
Note that the following specialization were invalid:
std::pair<T0, T1>
llvm::Optional<T>
Tests have been added to assert that former specialization are respected by the
standard usage of llvm::is_trivially_copyable, and that when a decent version
of std::is_trivially_copyable is available, llvm::is_trivially_copyable is
compared to std::is_trivially_copyable.
As of this patch, llvm::Optional is no longer considered trivially copyable,
even if T is. This is to be fixed in a later patch, as it has impact on a
long-running bug (see r347004)
Note that GCC warns about this UB, but this got silented by https://reviews.llvm.org/D50296.
Differential Revision: https://reviews.llvm.org/D54472
llvm-svn: 351701
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
