This just adds a warning for bitfields placed next to other bitfields
where the underlying type has different storage. Under the MS struct
bitfield packing ABI such bitfields are not packed.
C++ has a carve-out that makes a declaration with 'extern' explicitly
specified and no initializer be a declaration rather than a definition.
We now account for that to silence a diagnostic with:
```
extern const int i;
const int i = 12;
```
which is valid C++.
Addresses an issue that was brought up via post-commit review.
There are a few diagnostics that are incorrectly grouped under
`-Wc++20-compat` instead of `-Wpre-c++20-compat`.
I grepped for any remaining `-Wc++xy-compat` diagnostics, but they all
seem to actually be about compatibility with C++XY.
Fixes#138775.
This adds
- The parsing of `trivially_relocatable_if_eligible`,
`replaceable_if_eligible` keywords
- `__builtin_trivially_relocate`, implemented in terms of memmove. In
the future this should
- Add the appropriate start/end lifetime markers that llvm does not have
(`start_lifetime_as`)
- Add support for ptrauth when that's upstreamed
- the `__builtin_is_cpp_trivially_relocatable` and
`__builtin_is_replaceable` traits
Fixes#127609
Check for struct members that are structs filled only with function
pointers by recursively examining it. Since the lamba
IsFunctionPointerOrForwardDecl cannot call itself directly, move it into
a helper function, EntirelyFunctionPointers, so it can be called from
the lambda.
Add test for composite function pointer structs getting automatically
randomized.
Add more tests for validating automatic randomization vs explicitly
annotated with "randomize_layout", and excluded with
"no_randomize_layout".
Reorder the "should we randomize?" "if" statement to check for
enablement before checking for Record details.
Fixes#138355
Thanks to changes to type compatibility rules via WG14 N3007, these
functions can now be called with a compatible type even within the same
TU, which makes the -Wvisibility diagnostic too chatty to have on by
default.
So in C23 mode, -Wvisibility will only diagnose an incomplete tag type
declared in a function prototype. If the tag is defined in the
prototype, the diagnostic is silenced.
We already attempted to implement this (it was the intent of the paper),
in that parameters were never considered name-independent. However, we
failed to check that any previously found parameter declaration was also
name-independent.
Note that, as worded, the current resolution is insufficient (I wrote to
CWG with better wording), but there is some consensus on the design
outcome.
Fixes#136373
This drops the "and is incompatible with C++" phrasing from the
diagnostic unless -Wc++-compat is explicitly passed. This makes the
diagnostic less confusing when it is on by default rather than enabled
because of C++ compatibility concerns
This changes the type compatibility rules so that it is permitted to
redefine tag types within the same TU so long as they are equivalent
definitions.
It is intentionally not being exposed as an extension in older C
language modes. GCC does not do so and the feature doesn't seem
compelling enough to warrant it.
We already diagnose when a jump bypasses initialization in C++ because
such code is ill-formed there. However, we were not using this to
diagnose those same jumps in C.
-Wjump-bypasses-init is grouped under -Wc++-compat and diagnoses this
situation as a compatibility issue with C++. This diagnostic is off by
default.
The diagnostic could perhaps be enabled by default for C, but due to the
design of jump diagnostic handling, it not a trivial task. For now,
we'll add the diagnostic as off-by-default so we get incremental
improvement, but a follow-up could try to refactor jump diagnostics so
we can enable this by default in C and have it as a C++ compatibility
diagnostic as well.
This adds a new diagnostic group, -Wc++-keyword, which is off by default
and grouped under -Wc++-compat. The diagnostic catches use of C++
keywords in C code.
This change additionally fixes an issue with -Wreserved-identifier not
diagnosing use of reserved identifiers in function parameter lists in a
function declaration which is not a definition.
Fixes https://github.com/llvm/llvm-project/issues/21898
This patch adds templated `operator<<` for diagnostics that pass scoped
enums, saving people from `llvm::to_underlying()` clutter on the side of
emitting the diagnostic. This eliminates 80 out of 220 usages of
`llvm::to_underlying()` in Clang.
I also backported `std::is_scoped_enum_v` from C++23.
This adds a new diagnostic to warn about redeclaration of a tentative
definition in C. This is incompatible with C++, so the new diagnostic
group is under -Wc++-compat.
Post-commit review feedback on
https://github.com/llvm/llvm-project/pull/137166 raised a concern from
the Linux kernel about wanting to silence the new diagnostic when the
uninitialized object is a const member of a structure. These members can
be initialized later if the containing object is non-const, such as
through a call to memset, for example.
This splits the diagnostic groups into:
```
-Wc++-compat
-Wdefault-const-init
-Wdefault-const-init-field
-Wdefault-const-init-var
-Wdefault-const-init-unsafe
-Wdefault-const-init-field-unsafe
-Wdefault-const-init-var-unsafe
```
---------
Co-authored-by: Mariya Podchishchaeva <mariya.podchishchaeva@intel.com>
- Adds resource constructor that takes explicit binding for all resource
classes.
- Updates implementation of default resource constructor to initialize
resource handle to `poison`.
- Removes initialization of resource classes from Codegen.
- Initialization of `cbuffer` still needs to happen in `CGHLSLRuntime`
because it does not have a corresponding resource class type.
- Adds `ImplicitCastExpr` for builtin function calls. Sema adds these
automatically when a method of a template class is instantiated, but
some resource classes like `ByteAddressBuffer` are not templates so they
need to have this added explicitly.
Design proposal: llvm/wg-hlsl#197
Closes#134154
This introduces a new diagnostic, -Wc++-hidden-decl, which is grouped
under -Wc++-compat, that diagnoses declarations which are valid in C but
invalid in C++ due to the type being at the wrong scope. e.g.,
```
struct S {
struct T {
int x;
} t;
};
struct T t; // Valid C, invalid C++
```
This is implementing the other half of #21898
Unlike C++, C allows the definition of an uninitialized `const` object.
If the object has static or thread storage duration, it is still
zero-initialized, otherwise, the object is left uninitialized. In either
case, the code is not compatible with C++.
This adds a new diagnostic group, `-Wdefault-const-init-unsafe`, which
is on by default and diagnoses any definition of a `const` object which
remains uninitialized.
It also adds another new diagnostic group, `-Wdefault-const-init` (which
also enabled the `unsafe` variant) that diagnoses any definition of a
`const` object (including ones which are zero-initialized). This
diagnostic is off by default.
Finally, it adds `-Wdefault-const-init` to `-Wc++-compat`. GCC diagnoses
these situations under this flag.
Fixes#19297
When records contain fields with pointer authentication, even simple
copies can require
additional work be performed. This patch contains the core functionality
required to
handle user defined structs, as well as the implicitly constructed
structs for blocks, etc.
Co-authored-by: Ahmed Bougacha
Co-authored-by: Akira Hatanaka
Co-authored-by: John Mccall
Previously, analysis-based diagnostics (like -Wconsumed) had to be
enabled at file scope in order to be run at the end of each function
body. This meant that they did not respect #pragma clang diagnostic
enabling or disabling the diagnostic.
Now, these pragmas can control the diagnostic emission.
Fixes#42199
NB: This only fixes the crash introduced in Clang 19; we still accept
this code even though we shouldn’t:
```c++
struct S {
friend int f() { return 3; }
friend int f() = delete;
};
```
I tried figuring out a way to diagnose this redeclaration, but it seems
tricky because I kept running into issues around defaulted comparison
operators. From my testing, however, this fix here would still be
required even once we do start diagnosing this.
Fixes#135506.
The qualifier allows programmer to directly control how pointers are
signed when they are stored in a particular variable.
The qualifier takes three arguments: the signing key, a flag specifying
whether address discrimination should be used, and a non-negative
integer that is used for additional discrimination.
```
typedef void (*my_callback)(const void*);
my_callback __ptrauth(ptrauth_key_process_dependent_code, 1, 0xe27a) callback;
```
Co-Authored-By: John McCall rjmccall@apple.com
The deprecated, maybe_unused, and nodiscard standard attributes may all
be applied to a redeclaration after a definition has already appeared.
We were previously dropping the attribute in that case, now we retain
the attribute after the redeclaration.
Note: someday we may want to tablegen this as part of information from
Attr.td. We may also want to relax the restriction here so that the
syntax used does not matter. This is an intentionally conservative fix.
Fixes#135481
This is a basic implementation of P2719: "Type-aware allocation and
deallocation functions" described at http://wg21.link/P2719
The proposal includes some more details but the basic change in
functionality is the addition of support for an additional implicit
parameter in operators `new` and `delete` to act as a type tag. Tag is
of type `std::type_identity<T>` where T is the concrete type being
allocated. So for example, a custom type specific allocator for `int`
say can be provided by the declaration of
void *operator new(std::type_identity<int>, size_t, std::align_val_t);
void operator delete(std::type_identity<int>, void*, size_t, std::align_val_t);
However this becomes more powerful by specifying templated declarations,
for example
template <typename T> void *operator new(std::type_identity<T>, size_t, std::align_val_t);
template <typename T> void operator delete(std::type_identity<T>, void*, size_t, std::align_val_t););
Where the operators being resolved will be the concrete type being
operated over (NB. A completely unconstrained global definition as above
is not recommended as it triggers many problems similar to a general
override of the global operators).
These type aware operators can be declared as either free functions or
in class, and can be specified with or without the other implicit
parameters, with overload resolution performed according to the existing
standard parameter prioritisation, only with type parameterised
operators having higher precedence than non-type aware operators. The
only exception is destroying_delete which for reasons discussed in the
paper we do not support type-aware variants by default.
This is an alternative to
https://github.com/llvm/llvm-project/pull/122103
In SPIR-V, private global variables have the Private storage class. This
PR adds a new address space which allows frontend to emit variable with
this storage class when targeting this backend.
This is covered in this proposal: llvm/wg-hlsl@4c9e11a
This PR will cause addrspacecast to show up in several cases, like class
member functions or assignment. Those will have to be handled in the
backend later on, particularly to fixup pointer storage classes in some
functions.
Before this change, global variable were emitted with the 'Function'
storage class, which was wrong.
Fixes#21650
---
Clang currently inserts an implicit `return 0;` in `main()` when
compiling in `C89` mode, even though the `C89` standard doesn't require
this behavior. This patch changes that behavior by emitting a warning
instead of silently inserting the implicit return under `-pedantic`.
A file scope declaration without an initializer which is neither extern
nor thread_local is a tentative definition. If the declaration of an
identifier for an object is a tentative definition and has internal
linkage, the declared type shall not be an incomplete type.
Clang was previously failing to diagnose this in -pedantic mode.
Fixes#50661
---------
Co-authored-by: Mariya Podchishchaeva <mariya.podchishchaeva@intel.com>
This introduces a new class 'UnsignedOrNone', which models a lite
version of `std::optional<unsigned>`, but has the same size as
'unsigned'.
This replaces most uses of `std::optional<unsigned>`, and similar
schemes utilizing 'int' and '-1' as sentinel.
Besides the smaller size advantage, this is simpler to serialize, as its
internal representation is a single unsigned int as well.
This is a follow-up to #132129.
Currently, only `Parser` and `SemaBase` get a `DiagCompat()` helper; I’m
planning to keep refactoring compatibility warnings and add more helpers
to other classes as needed. I also refactored a single parser compat
warning just to make sure everything works properly when diagnostics
across multiple components (i.e. Sema and Parser in this case) are
involved.
This reverts an earlier attempt
(adb0d8ddceb143749c519d14b8b31b481071da77 and
50e5411e4247421fd606f0a206682fcdf0303ae3) to support these expansions,
which was limited to type arguments and which subverted the purpose
of SubstTemplateTypeParmType.
This propagates the ArgumentPackSubstitutionIndex along with the
AssociatedConstraint, so that the pack expansion works, without
needing any new transforms or otherwise any changes to the template
instantiation process.
This keeps the tests from the reverted commits, and adds a few more
showing the new solution also works for NTTPs.
Fixes https://github.com/llvm/llvm-project/issues/131798
This is the last item of the OpenACC 3.3 spec. It includes the
implicit-name version of 'routine', plus significant refactorings to
make the two work together. The implicit name version is represented as
an attribute on the function call. This patch also implements the
clauses for the implicit-name version, as well as the A.3.4 warning.
This introduces some tablegen helpers for defining compatibility
warnings. The main aim of this is to both simplify adding new
compatibility warnings as well as to unify the naming of compatibility
warnings.
I’ve refactored ~half of the compatiblity warnings (that follow the
usual scheme) in `DiagnosticSemaKinds.td` for illustration purposes and
also to simplify/unify the wording of some of them (I also corrected a
typo in one of them as a drive-by fix).
I haven’t (yet) migrated *all* warnings even in that one file, and there
are some more specialised ones for which the scheme I’ve established
here doesn’t work (e.g. because they’re warning+error instead of
warning+extwarn; however, warning+extension *is* supported), but the
point of this isn’t to implement *all* compatibility-related warnings
this way, only to make the common case a bit easier to handle.
This currently also only handles C++ compatibility warnings, but it
should be fairly straight-forward to extend the tablegen code so it can
also be used for C compatibility warnings (if this gets merged, I’m
planning to do that in a follow-up pr).
The vast majority of compatibility warnings are emitted by writing
```c++
Diag(Loc, getLangOpts().CPlusPlusYZ ? diag::ext_... : diag::warn_...)
```
in accordance with which I’ve chosen the following naming scheme:
```c++
Diag(Loc, getLangOpts().CPlusPlusYZ ? diag::compat_cxxyz_foo : diag::compat_pre_cxxyz_foo)
```
That is, for a warning about a C++20 feature—i.e. C++≤17
compatibility—we get:
```c++
Diag(Loc, getLangOpts().CPlusPlus20 ? diag::compat_cxx20_foo : diag::compat_pre_cxx20_foo)
```
While there is an argument to be made against writing ‘`compat_cxx20`’
here since is technically a case of ‘C++17 compatibility’ and not ‘C++20
compatibility’, I at least find this easier to reason about, because I
can just write the same number 3 times instead of having to use
`ext_cxx20_foo` but `warn_cxx17_foo`. Instead, I like to read this as a
warning about the ‘compatibility *of* a C++20 feature’ rather than
‘*with* C++17’.
I also experimented with moving all compatibility warnings to a separate
file, but 1. I don’t think it’s worth the effort, and 2. I think it
hurts compile times a bit because at least in my testing I felt that I
had to recompile more code than if we just keep e.g. Sema-specific
compat warnings in the Sema diagnostics file.
Instead, I’ve opted to put them all in the same place within any one
file; currently this is a the very top but I don’t really have strong
opinions about this.
Fixes#125810
---
This patch resolves an issue in Clang where the `-Wunused-variable`
warning was suppressed for structured bindings with elements marked
`[[maybe_unused]]`, causing the entire declaration to be treated as used
and preventing the warning from being emitted.
