Summary:
Clang has support for boolean vectors, these builtins expose the LLVM
instruction of the same name. This differs from a manual load and select
by potentially suppressing traps from deactivated lanes.
Fixes: https://github.com/llvm/llvm-project/issues/107753
Summary:
We added boolean vectors in clang 15 and wish to extend them further in
clang-22. However, there's no way to query for their support as they are
separate to the normal extended vector type. This adds a feature so we
can check for it as a feature directly.
The new builtin `__builtin_dedup_pack` removes duplicates from list of
types.
The added builtin is special in that they produce an unexpanded pack
in the spirit of P3115R0 proposal.
Produced packs can be used directly in template argument lists and get
immediately expanded as soon as results of the computation are
available.
It allows to easily combine them, e.g.:
```cpp
template <class ...T>
struct Normalize {
// Note: sort is not included in this PR, it illustrates the idea.
using result = std::tuple<
__builtin_sort_pack<
__builtin_dedup_pack<int, double, T...>...
>...>;
}
;
```
Limitations:
- only supported in template arguments and bases,
- can only be used inside the templates, even if non-dependent,
- the builtins cannot be assigned to template template parameters.
The actual implementation proceeds as follows:
- When the compiler encounters a `__builtin_dedup_pack` or other
type-producing
builtin with dependent arguments, it creates a dependent
`TemplateSpecializationType`.
- During substitution, if the template arguments are non-dependent, we
will produce: a new type `SubstBuiltinTemplatePackType`, which stores
an argument pack that needs to be substituted. This type is similar to
the existing `SubstTemplateParmPack` in that it carries the argument
pack that needs to be expanded further. The relevant code is shared.
- On top of that, Clang also wraps the resulting type into
`TemplateSpecializationType`, but this time only as a sugar.
- To actually expand those packs, we collect the produced
`SubstBuiltinTemplatePackType` inside `CollectUnexpandedPacks`.
Because we know the size of the produces packs only after the initial
substitution, places that do the actual expansion will need to have a
second run over the substituted type to finalize the expansions (in
this patch we only support this for template arguments, see
`ExpandTemplateArgument`).
If the expansion are requested in the places we do not currently
support, we will produce an error.
More follow-up work will be needed to fully shape this:
- adding the builtin that sorts types,
- remove the restrictions for expansions,
- implementing P3115R0 (scheduled for C++29, see
https://github.com/cplusplus/papers/issues/2300).
A call through a function pointer has no associated FunctionDecl, but it
still might have a nodiscard return type. Ensure there is a codepath to
emit the nodiscard warning in this case.
Fixes#142453
Summary:
It's extremely common to conditionally blend two vectors. Previously
this was done with mask registers, which is what the normal ternary code
generation does when used on a vector. However, since Clang 15 we have
supported boolean vector types in the compiler. These are useful in
general for checking the mask registers, but are currently limited
because they do not map to an LLVM-IR select instruction.
This patch simply relaxes these checks, which are technically forbidden
by
the OpenCL standard. However, general vector support should be able to
handle these. We already support this for Arm SVE types, so this should
be make more consistent with the clang vector type.
These builtins are modeled on the clzg/ctzg builtins, which accept an
optional second argument. This second argument is returned if the first
argument is 0. These builtins unconditionally exhibit zero-is-undef
behaviour, regardless of target preference for the other ctz/clz
builtins. The builtins have constexpr support.
Fixes#154113
Both these attributes were introduced in ab1dc2d54db5 ("Thread Safety
Analysis: add support for before/after annotations on mutexes") back in
2015 as "beta" features.
Anecdotally, we've been using `-Wthread-safety-beta` for years without
problems.
Furthermore, this feature requires the user to explicitly use these
attributes in the first place.
After 10 years, let's graduate the feature to the stable feature set,
and reserve `-Wthread-safety-beta` for new upcoming features.
The immediate evaluation context needs the lambda scope info to
propagate some flags, however that LSI was removed in
ActOnFinishFunctionBody which happened before rebuilding a lambda
expression.
The last attempt destroyed LSI at the end of the block scope, after
which we still need it in DiagnoseShadowingLambdaDecls.
This also converts the wrapper function to default arguments as a
drive-by fix, as well as does some cleanup.
Fixes https://github.com/llvm/llvm-project/issues/145776
We have a flag that tracks whether a `CXXThisExpr` refers to a `*this`
capture in a lambda with a dependent explicit object parameter; this is
to mark it and member accesses involving it as dependent because there
is no other way to track that (DREs have a similar flag); when
instantiating the lambda, we need to always rebuild the `CXXThisExpr` to
potentially clear that flag if the explicit object parameter is no
longer dependent.
Fixes#154054.
Revert llvm/llvm-project#154018 changes due to excessive _false
positives_. The warning caused multiple benign reports in large
codebases (e.g. _Linux kernel_, _Fuchsia_, _tcpdump_). Since many of
these concatenations are intentional and follow project style rules, the
diagnostic introduced more false positives than value. This will be
revisited as a potential `clang-tidy` check instead.
Summary:
This is a standalone tool that does the wrapper stage of the
`clang-linker-wrapper`. We want this to be an external tool because
currently there's no easy way to split apart what the
clang-linker-wrapper is doing under the hood. With this tool, users can
manually extract files with `clang-offload-packager`, feed them through
`clang --target=<triple>` and then use this tool to generate a `.bc`
file they can give to the linker. The goal here is to make reproducing
the linker wrapper steps easier.
The Generic_GCC::GCCInstallationDetector class picks the GCC
installation directory with the largest version number. Since the
location of the libstdc++ include directories is tied to the GCC
version, this can break C++ compilation if the libstdc++ headers for
this particular GCC version are not available. Linux distributions tend
to package the libstdc++ headers separately from GCC. This frequently
leads to situations in which a newer version of GCC gets installed as a
dependency of another package without installing the corresponding
libstdc++ package. Clang then fails to compile C++ code because it
cannot find the libstdc++ headers. Since libstdc++ headers are in fact
installed on the system, the GCC installation continues to work, the
user may not be aware of the details of the GCC detection, and the
compiler does not recognize the situation and emit a warning, this
behavior can be hard to understand - as witnessed by many related bug
reports over the years.
The goal of this work is to change the GCC detection to prefer GCC
installations that contain libstdc++ include directories over those
which do not. This should happen regardless of the input language since
picking different GCC installations for a build that mixes C and C++
might lead to incompatibilities.
Any change to the GCC installation detection will probably have a
negative impact on some users. For instance, for a C user who relies on
using the GCC installation with the largest version number, it might
become necessary to use the --gcc-install-dir option to ensure that this
GCC version is selected.
This seems like an acceptable trade-off given that the situation for
users who do not have any special demands on the particular GCC
installation directory would be improved significantly.
This patch does not yet change the automatic GCC installation directory
choice. Instead, it does introduce a warning that informs the user about
the future change if the chosen GCC installation directory differs from
the one that would be chosen if the libstdc++ headers are taken into
account.
See also this related Discourse discussion:
https://discourse.llvm.org/t/rfc-take-libstdc-into-account-during-gcc-detection/86992.
The immediate evaluation context needs the lambda scope info to
propagate some flags, however that LSI was removed in
ActOnFinishFunctionBody which happened before rebuilding a lambda
expression.
This also converts the wrapper function to default arguments as a
drive-by fix.
Fixes https://github.com/llvm/llvm-project/issues/145776
This updates the pointer authentication documentation to include a
complete description of the existing functionaliy and behaviour, details
of the more complex aspects of the semantics and security properties,
and the Apple arm64e ABI design.
Co-authored-by: Ahmed Bougacha
Co-authored-by: Akira Hatanaka
Co-authored-by: John Mccall
---------
Co-authored-by: Ahmed Bougacha <ahmed@bougacha.org>
Co-authored-by: Akira Hatanaka <ahatanak@gmail.com>
Co-authored-by: John Mccall <rjmccall@apple.com>
For backwards compatibility reasons the `ptrauth_qualifier` and
`ptrauth_intrinsic` features need to be testable with `__has_feature()`
on Apple platforms, but for other platforms this backwards compatibility
issue does not exist.
This PR resolves these issues by making the `ptrauth_qualifier` and
`ptrauth_intrinsic` tests conditional upon a darwin target. This also
allows us to revert the ptrauth_qualifier check from an extension to a
feature test again, as is required on these platforms.
At the same time we introduce a new predefined macro `__PTRAUTH__` that
answers the same question as `__has_feature(ptrauth_qualifier)` and
`__has_feature(ptrauth_intrinsic)` as those tests are synonymous and
only exist separately for compatibility reasons.
The requirement to test for the `__PTRAUTH__` macro also resolves the
hazard presented by mixing the `ptrauth_qualifier` flag (that impacts
ABI and security policies) with `-pedantics-errors`, which makes
`__has_extension` return false for all extensions.
---------
Co-authored-by: Aaron Ballman <aaron@aaronballman.com>
Incompatible pointer to integer conversion diagnostic checks would
trigger an assertion when the designated initializer is for an array of
unknown bounds.
Fixes#154046
Simple fix for this particular html tag. A more complete solution should
be implemented.
1. Add all html tags to table so they are recognized. Some input on what
is desirable/safe would be appreciated
2. Change the lex strategy to deal with this in a different manner
Fixes#32680
---------
Co-authored-by: Brock Denson <brock.denson@virscient.com>
This commit is a re-do of e4a8969e56572371201863594b3a549de2e23f32,
which got reverted, with the same goal: dramatically speed-up clang-tidy
by avoiding doing work in system headers (which is wasteful as warnings
are later discarded). This proposal was already discussed here with
favorable feedback: https://github.com/llvm/llvm-project/pull/132725
The novelty of this patch is:
- It's less aggressive: it does not fiddle with AST traversal. This
solves the issue with the previous patch, which impacted the ability to
inspect parents of a given node.
- Instead, what we optimize for is exitting early in each `Traverse*`
function of `MatchASTVisitor` if the node is in a system header, thus
avoiding calling the `match()` function with its corresponding callback
(when there is a match).
- It does not cause any failing tests.
- It does not move `MatchFinderOptions` - instead we add a user-defined
default constructor which solves the same problem.
- It introduces a function `shouldSkipNode` which can be extended for
adding more conditions. For example there's a PR open about skipping
modules in clang-tidy where this could come handy:
https://github.com/llvm/llvm-project/pull/145630
As a benchmark, I ran clang-tidy with all checks activated, on a single
.cpp file which #includes all the standard C++ headers, then measure the
time as well as found warnings.
On trunk:
```
Suppressed 75413 warnings (75413 in non-user code).
real 0m12.418s
user 0m12.270s
sys 0m0.129s
```
With this patch:
```
Suppressed 11448 warnings (11448 in non-user code).
Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
real 0m1.666s
user 0m1.538s
sys 0m0.129s
```
With the original patch that got reverted:
```
Suppressed 11428 warnings (11428 in non-user code).
real 0m1.193s
user 0m1.096s
sys 0m0.096s
```
We therefore get a dramatic reduction in number of warnings and runtime,
with no change in functionality.
The remaining warnings are due to `PPCallbacks` - implementing a similar
system-header exclusion mechanism there can lead to almost no warnings
left in system headers. This does not bring the runtime down as much,
though, so it's probably not worth the effort.
Fixes#52959
Co-authored-by: Carlos Gálvez <carlos.galvez@zenseact.com>
We've backported a lot more features from C to previous C standards than
we were documenting. I took a pass over the c_status page for Clang and
pulled more entries to add to our documentation.
This modifies InjectAnonymousStructOrUnionMembers to inject an
IndirectFieldDecl and mark it invalid even if its name conflicts with
another name in the scope.
This resolves a crash on a further diagnostic
diag::err_multiple_mem_union_initialization which via
findDefaultInitializer relies on these declarations being present.
Fixes#149985
The script copies `ReleaseNotesTemplate.txt` to corresponding
`ReleaseNotes.rst`/`.md` to clear release notes.
The suffix of `ReleaseNotesTemplate.txt` must be `.txt`. If it is
`.rst`/`.md`, it will be treated as a documentation source file when
building documentation.
These warnings are reported on a per expression basis, however some
potential misaligned accesses are discarded before that happens. The
problem is when a new expression starts while processing another
expression. The new expression will end first and emit all potential
misaligned accesses collected up to that point. That includes candidates
that were found in the parent expression, even though they might have
gotten discarded later.
Fixed by checking if the candidate is located withing the currently
processed expression.
Fixes#144729
Added constant evaluation support for `__builtin_elementwise_abs` on integer, float and vector type.
fixes#152276
---------
Co-authored-by: Simon Pilgrim <llvm-dev@redking.me.uk>
When stashing the tokens of a parameter of a member function, we would
munch an ellipsis, as the only considered terminal conditions were `,`
and `)`.
Fixes#153445
The goal is to correctly identify diagnostics that are emitted by virtue
of -Wformat-signedness.
Before this change, diagnostic messages triggered by -Wformat-signedness
might look like:
format specifies type 'unsigned int' but the argument has type 'int'
[-Wformat]
signedness of format specifier 'u' is incompatible with 'c' [-Wformat]
With this change:
format specifies type 'unsigned int' but the argument has type 'int',
which differs in signedness [-Wformat-signedness]
signedness of format specifier 'u' is incompatible with 'c'
[-Wformat-signedness]
Fix:
- handleFormatSignedness can now return NoMatchSignedness. Callers
handle this.
- warn_format_conversion_argument_type extends the message it used to
emit by a string that
mentions "signedness".
- warn_format_cmp_specifier_sign_mismatch is now correctly categorized
as a
diagnostic controlled by -Wformat-signedness.
Allow CCEKind::ExplicitBool in BuildConvertedConstantExpression for
pre-C++11 contexts, similar to the existing TempArgStrict exception.
This enables explicit(bool) to work as a C++20 extension in earlier
language modes without triggering assertion failures.
Fixes#152729
---------
Co-authored-by: Jongmyeong Choi <cheesechoi@gmail.com>
This patch handles the strided update in the `#pragma omp target update
from(data[a🅱️c])` directive where 'c' represents the strided access
leading to non-contiguous update in the `data` array when the offloaded
execution returns the control back to host from device using the `from`
clause.
Issue: Clang CodeGen where info is generated for the particular
`MapType` (to, from, etc), it was failing to detect the strided access.
Because of this, the `MapType` bits were incorrect when passed to
runtime. This led to incorrect execution (contiguous) in the
libomptarget runtime code.
Added a minimal testcase that verifies the working of the patch.
Fixes#152829
---
This patch addresses the issue where the preprocessor could crash when
parsing `#embed` parameters containing unmatched closing brackets
```cpp
#embed "file" prefix(])
#embed "file" prefix(})
```
If a template argument in a partial specialization of a variable
template directly refers to a NTTP of the specialization without
implicit type conversion it was assumed that the NTTP is identical to
that of the primary template.
This doesn't hold if the primary template's NTTP uses a deduced type, so
instead compare the types explicitly as well.
The affected function is used only to provide an improved early error if
the partial specialization has identical template arguments to the
primary template. The actual check that the partial specialization is
more specialized happens later.
Fixes#118190Fixes#152750
