When rebuilding immediate invocations inside
`RemoveNestedImmediateInvocation()`, we employed a `TreeTransform` to
exercise the traversal. The transformation has a side effect that, for
template specialization types, their default template arguments are
substituted separately, and if any lambdas are present, they will be
transformed into distinct types than those used to instantiate the
templates right before the `consteval` handling.
This resulted in `B::func()` getting redundantly instantiated for the
case in question. Since we're also in an immediate evaluation context,
the body of `foo()` would also get instantiated, so we end up with a
spurious friend redefinition error.
Like what we have done in `ComplexRemove`, this patch also avoids the
lambda's transformation in TemplateInstantiator if we know we're
rebuilding immediate calls. In addition, this patch also consolidates
the default argument substitution logic in
`CheckTemplateArgumentList()`.
Fixes#107175
The PR reapply https://github.com/llvm/llvm-project/pull/97308.
- Implement [CWG1815](https://wg21.link/CWG1815): Support lifetime
extension of temporary created by aggregate initialization using a
default member initializer.
- Fix crash that introduced in
https://github.com/llvm/llvm-project/pull/97308. In
`InitListChecker::FillInEmptyInitForField`, when we enter
rebuild-default-init context, we copy all the contents of the parent
context to the current context, which will cause the `MaybeODRUseExprs`
to be lost. But we don't need to copy the entire context, only the
`DelayedDefaultInitializationContext` was required, which is used to
build `SourceLocExpr`, etc.
---------
Signed-off-by: yronglin <yronglin777@gmail.com>
This reverts commit 45c8766973bb3bb73dd8d996231e114dcf45df9f
and 049512e39d96995cb373a76cf2d009a86eaf3aab.
This change triggers failed asserts on inputs like this:
struct a {
} constexpr b;
class c {
public:
c(a);
};
class B {
public:
using d = int;
struct e {
enum { f } g;
int h;
c i;
d j{};
};
};
B::e k{B::e::f, int(), b};
Compiled like this:
clang -target x86_64-linux-gnu -c repro.cpp
clang: ../../clang/lib/CodeGen/CGExpr.cpp:3105: clang::CodeGen::LValue
clang::CodeGen::CodeGenFunction::EmitDeclRefLValue(const clang::DeclRefExpr*):
Assertion `(ND->isUsed(false) || !isa<VarDecl>(ND) || E->isNonOdrUse() ||
!E->getLocation().isValid()) && "Should not use decl without marking it used!"' failed.
[P2641R4](https://wg21.link/P2641R4)
This new builtin function is declared `consteval`. Support for
`-fexperimental-new-constant-interpreter` will be added in a later
patch.
---------
Co-authored-by: cor3ntin <corentinjabot@gmail.com>
In #78436 we made some SourceLocExpr dependent to
deal with the fact that their value should reflect the name of
specialized function - rather than the rtemplate in which they are first
used.
However SourceLocExpr are unusual in two ways
- They don't depend on template arguments
- They morally depend on the context in which they are used (rather than
called from).
It's fair to say that this is quite novels and confuses clang. In
particular, in some cases, we used to create dependent SourceLocExpr and
never subsequently transform them, leaving dependent objects in
instantiated functions types. To work around that we avoid replacing
SourceLocExpr when we think they could remain dependent.
It's certainly not perfect but it fixes a number of reported bugs, and
seem to only affect scenarios in which the value of the SourceLocExpr
does not matter (overload resolution).
Fixes#106428Fixes#81155Fixes#80210Fixes#85373
---------
Co-authored-by: Aaron Ballman <aaron@aaronballman.com>
HLSL output parameters are denoted with the `inout` and `out` keywords
in the function declaration. When an argument to an output parameter is
constructed a temporary value is constructed for the argument.
For `inout` pamameters the argument is initialized via copy-initialization
from the argument lvalue expression to the parameter type. For `out`
parameters the argument is not initialized before the call.
In both cases on return of the function the temporary value is written
back to the argument lvalue expression through an implicit assignment
binary operator with casting as required.
This change introduces a new HLSLOutArgExpr ast node which represents
the output argument behavior. The OutArgExpr has three defined children:
- An OpaqueValueExpr of the argument lvalue expression.
- An OpaqueValueExpr of the copy-initialized parameter.
- A BinaryOpExpr assigning the first with the value of the second.
Fixes#87526
---------
Co-authored-by: Damyan Pepper <damyanp@microsoft.com>
Co-authored-by: John McCall <rjmccall@gmail.com>
Introducing `HLSLAttributedResourceType` - a new type that is similar to
`AttributedType` but with additional data specific to HLSL resources.
`AttributeType` currently only stores an attribute kind and no
additional data from the type attribute parameters. This does not really
work for HLSL resources since its type attributes contain non-boolean
values that need to be retained as well.
For example:
```
template <typename T> class RWBuffer {
__hlsl_resource_t [[hlsl::resource_class(uav)]] [[hlsl::is_rov]] handle;
};
```
The data `HLSLAttributedResourceType` needs to eventually store are:
- resource class (SRV, UAV, CBuffer, Sampler)
- texture dimension(1-3)
- flags is_rov, is_array, is_feedback and is_multisample
- contained type
All of these values except contained type will be stored in
`HLSLAttributedResourceType::Attributes` struct and accessed
individually via the fields. There is also `Data` alias that covers all
of these values as a `unsigned` which is used for hashing and the AST
type serialization.
During type attribute processing all HLSL type attributes will be
validated and collected by SemaHLSL (by
`SemaHLSL::handleResourceTypeAttr`) and in the end combined into a
single `HLSLAttributedResourceType` instance (in
`SemaHLSL::ProcessResourceTypeAttributes`). `SemaHLSL` will also need to
short-term store the `TypeLoc` information for the new type that will be
grabbed by `TypeSpecLocFiller` soon after the type is created.
Part 1/2 of #104861
The primary motivation behind this is to allow the enum type to be
referred to earlier in the Sema.h file which is needed for #106321.
It was requested in #106321 that a scoped enum be used (rather than
moving the enum declaration earlier in the Sema class declaration).
Unfortunately doing this creates a lot of churn as all use sites of the
enum constants had to be changed. Appologies to all downstream forks in
advanced.
Note the AA_ prefix has been dropped from the enum value names as they
are now redundant.
As per [1] the indices for a matrix element access operator shall have
integral or unscoped enumeration types and be non-negative. At the
moment, the index expression is converted to SizeType irrespective of
the signedness of the index expression. This causes implicit sign
conversion warnings if any of the indices is signed.
As per the spec, using signed types as indices is allowed and should not
cause any warnings. If the index expression is signed, extend to
SignedSizeType to avoid the warning.
[1]
https://clang.llvm.org/docs/MatrixTypes.html#matrix-type-element-access-operator
PR: https://github.com/llvm/llvm-project/pull/103044
https://cplusplus.github.io/CWG/issues/722.html
nullptr passed to a variadic function now converted to void* in C++.
This does not affect C23 nullptr.
Also fixes -Wformat-pedantic so that it no longer warns for nullptr
passed to %p (because it is converted to void* in C++ and it is allowed
for va_arg(ap, void*) in C23)
When various `Sema*.h` and `Sema*.cpp` files were created, cleanup of
`Sema.h` includes and forward declarations was left for the later.
Now's the time. This commit touches `Sema.h` and Sema components:
1. Unused includes are removed.
2. Unused forward declarations are removed.
3. Missing includes are added (those files are largely IWYU-clean now).
4. Includes were converted into forward declarations where possible.
As this commit focuses on headers, all changes to `.cpp` files were
minimal, and were aiming at keeping everything buildable.
A class member named by an expression in a member function that may instantiate to a static _or_ non-static member is represented by a `UnresolvedLookupExpr` in order to defer the implicit transformation to a class member access expression until instantiation. Since `ASTContext::getDecltypeType` only creates a `DecltypeType` that has a `DependentDecltypeType` as its canonical type when the operand is instantiation dependent, and since we do not transform types unless they are instantiation dependent, we need to mark the `UnresolvedLookupExpr` as instantiation dependent in order to correctly build a `DecltypeType` using the expression as its operand with a `DependentDecltypeType` canonical type. Fixes#99873.
HLSL has a set of intangible types which are described in in the
[draft HLSL Specification
(**[Basic.types]**)](https://microsoft.github.io/hlsl-specs/specs/hlsl.pdf):
There are special implementation-defined types such as handle types,
which fall into a category of standard intangible types. Intangible
types are types that have no defined object representation or value
representation, as such the size is unknown at compile time.
A class type T is an intangible class type if it contains an base
classes or members of intangible class type, standard intangible type,
or arrays of such types. Standard intangible types and intangible class
types are collectively called intangible
types([9](https://microsoft.github.io/hlsl-specs/specs/hlsl.html#Intangible)).
This PR implements one standard intangible type `__hlsl_resource_t`
and sets up the infrastructure that will make it easier to add more
in the future, such as samplers or raytracing payload handles. The
HLSL intangible types are declared in
`clang/include/clang/Basic/HLSLIntangibleTypes.def` and this file is
included with related macro definition in most places that require edits
when a new type is added.
The new types are added as keywords and not typedefs to make sure they
cannot be redeclared, and they can only be declared in builtin implicit
headers. The `__hlsl_resource_t` type represents a handle to a memory
resource and it is going to be used in builtin HLSL buffer types like this:
template <typename T>
class RWBuffer {
[[hlsl::contained_type(T)]]
[[hlsl::is_rov(false)]]
[[hlsl::resource_class(uav)]]
__hlsl_resource_t Handle;
};
Part 1/3 of llvm/llvm-project#90631.
---------
Co-authored-by: Justin Bogner <mail@justinbogner.com>
We have a mechanism to allow folding expressions that aren't ICEs as an
extension; use it more consistently.
This ends up causing bad effects on diagnostics in a few cases, but
that's not specific to shifts; it's a general issue with the way those
uses handle overflow diagnostics.
The PR #93430 introduced an assertion that did not make any sense. and
caused a regression. The fix is to simply remove the assertion.
No changelog. the intent is to backport this fix to clang 19.
The builtin computes the discriminator for a type, which can be used to
sign/authenticate function pointers and member function pointers.
If the type passed to the builtin is a C++ member function pointer type,
the result is the discriminator used to signed member function pointers
of that type. If the type is a function, function pointer, or function
reference type, the result is the discriminator used to sign functions
of that type. It is ill-formed to use this builtin with any other type.
A call to this function is an integer constant expression.
Co-Authored-By: John McCall rjmccall@apple.com
Enabled in clang using:
-fptrauth-indirect-gotos
and at the IR level using function attribute:
"ptrauth-indirect-gotos"
Signing uses IA and a per-function integer discriminator. The
discriminator isn't ABI-visible, and is currently:
ptrauth_string_discriminator("<function_name> blockaddress")
A sufficiently sophisticated frontend could benefit from per-indirectbr
discrimination, which would need additional machinery, such as allowing
"ptrauth" bundles on indirectbr. For our purposes, the simple scheme
above is sufficient.
This approach doesn't support subtracting label addresses and using
the result as offsets, because each label address is signed.
Pointer arithmetic on signed pointers corrupts the signature bits,
and because label address expressions aren't typed beyond void*,
we can't do anything reliably intelligent on the arithmetic exprs.
Not signing addresses when used to form offsets would allow
easily hijacking control flow by overwriting the offset.
This diagnoses the basic cases (`&&lbl2 - &&lbl1`) in the frontend,
while we evaluate either alternative implementations (e.g., lowering
blockaddress to a bb number, and indirectbr to a checked jump-table),
or better diagnostics (both at the frontend level and on unencodable
IR constants).
In #89713, we made qualified, parenthesized id-expression ill-formed in
and address of expressions.
The expected behavior should instead be to form a pointer (rather than a
pointer to member)
The fix has been suggested by @zwuis and the tests by
@hubert-reinterpretcast.
It is worth pointing out that some of these tests seem rejected by all
compilers, however the tests do seem correct.
Fixes#89713Fixes#40906
---------
Co-authored-by: YanzuoLiu <zwuis@outlook.com>
Instead of playing "whack a mole" with places where #embed should be
expanded as comma-separated list, just inject each byte as a token back
into the stream, separated by commas.
Unfortunately, #95660 has caused a regression in DeduceReturnType(),
where some of the local recursive lambdas are getting incorrectly rejected.
This reverts commit 5548ea34341e9d0ae645719c34b466ca3b9eaa5a. Also, this
adds an offending case to the test.
Closes#98526
This reverts commit ce4aada6e2135e29839f672a6599db628b53295d and a
follow-up patch 8ef26f1289bf069ccc0d6383f2f4c0116a1206c1.
This new warning can not be fully suppressed by the
`-Wno-missing-dependent-template-keyword` flag, this gives developer no
time to do the cleanup in a large codebase, see https://github.com/llvm/llvm-project/pull/98547#issuecomment-2228250884
Reapplies #92957, fixing an instance where the `template` keyword was
missing prior to a dependent name in `llvm/ADT/ArrayRef.h`. An
_alias-declaration_ is used to work around a bug affecting GCC releases
before 11.1 (see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94799) which
rejects the use of the `template` keyword prior to the
_nested-name-specifier_ in the class member access.
[clang][ARM] Fix warning for using VFP from interrupts.
This warning has three issues:
- The interrupt attribute causes the function to return using an
exception
return instruction. This warning allows calls from one function with
the interrupt attribute to another, and the diagnostic text suggests
that not having the attribute on the callee is a problem. Actually
making such a call will lead to a double exception return, which is
unpredictable according to the ARM architecture manual section
B9.1.1, "Restrictions on exception return instructions". Even on
machines where an exception return from user/system mode is
tolerated, if the callee's interrupt type is anything other than a
supervisor call or secure monitor call, it will also return to a
different address than a normal function would. For example,
returning from an "IRQ" handler will return to lr - 4, which will
generally result in calling the same function again.
- The interrupt attribute currently does not cause caller-saved VFP
registers to be saved and restored if they are used, so putting
__attribute__((interrupt)) on a called function doesn't prevent it
from clobbering VFP state.
- It is part of the -Wextra diagnostic group and can't be individually
disabled when using -Wextra, which also means the diagnostic text of
this specific warning appears in the documentation of -Wextra.
This change addresses all three issues by instead generating a warning
for any interrupt handler where the vfp feature is enabled. The warning
is
also given its own diagnostic group.
Closes#34876.
[clang][ARM] Emit an error when an interrupt handler is called.
Closes#95359.
CWG1835 was one of the many core issues resolved by P1787R6: "Declarations and where to
find them" (http://wg21.link/p1787r6). Its resolution changes how
member-qualified names (as defined by [basic.lookup.qual.general] p2) are looked
up. This patch implementation that resolution.
Previously, an _identifier_ following `.` or `->` would be first looked
up in the type of the object expression (i.e. qualified lookup), and
then in the context of the _postfix-expression_ (i.e. unqualified
lookup) if nothing was found; the result of the second lookup was
required to name a class template. Notably, this second lookup would
occur even when the object expression was dependent, and its result
would be used to determine whether a `<` token is the start of a
_template-argument_list_.
The new wording in [basic.lookup.qual.general] p2 states:
> A member-qualified name is the (unique) component name, if any, of
> - an _unqualified-id_ or
> - a _nested-name-specifier_ of the form _`type-name ::`_ or
_`namespace-name ::`_
>
> in the id-expression of a class member access expression. A
***qualified name*** is
> - a member-qualified name or
> - the terminal name of
> - a _qualified-id_,
> - a _using-declarator_,
> - a _typename-specifier_,
> - a _qualified-namespace-specifier_, or
> - a _nested-name-specifier_, _elaborated-type-specifier_, or
_class-or-decltype_ that has a _nested-name-specifier_.
>
> The _lookup context_ of a member-qualified name is the type of its
associated object expression (considered dependent if the object
expression is type-dependent). The lookup context of any other qualified
name is the type, template, or namespace nominated by the preceding
_nested-name-specifier_.
And [basic.lookup.qual.general] p3 now states:
> _Qualified name lookup_ in a class, namespace, or enumeration performs
a search of the scope associated with it except as specified below.
Unless otherwise specified, a qualified name undergoes qualified name
lookup in its lookup context from the point where it appears unless the
lookup context either is dependent and is not the current instantiation
or is not a class or class template. If nothing is found by qualified
lookup for a member-qualified name that is the terminal name of a
_nested-name-specifier_ and is not dependent, it undergoes unqualified
lookup.
In non-standardese terms, these two paragraphs essentially state the
following:
- A name that immediately follows `.` or `->` in a class member access
expression is a member-qualified name
- A member-qualified name will be first looked up in the type of the
object expression `T` unless `T` is a dependent type that is _not_ the
current instantiation, e.g.
```
template<typename T>
struct A
{
void f(T* t)
{
this->x; // type of the object expression is 'A<T>'. although 'A<T>' is dependent, it is the
// current instantiation so we look up 'x' in the template definition context.
t->y; // type of the object expression is 'T' ('->' is transformed to '.' per [expr.ref]).
// 'T' is dependent and is *not* the current instantiation, so we lookup 'y' in the
// template instantiation context.
}
};
```
- If the first lookup finds nothing and:
- the member-qualified name is the first component of a
_nested-name-specifier_ (which could be an _identifier_ or a
_simple-template-id_), and either:
- the type of the object expression is the current instantiation and it
has no dependent base classes, or
- the type of the object expression is not dependent
then we lookup the name again, this time via unqualified lookup.
Although the second (unqualified) lookup is stated not to occur when the
member-qualified name is dependent, a dependent name will _not_ be
dependent once the template is instantiated, so the second lookup must
"occur" during instantiation if qualified lookup does not find anything.
This means that we must perform the second (unqualified) lookup during
parsing even when the type of the object expression is dependent, but
those results are _not_ used to determine whether a `<` token is the
start of a _template-argument_list_; they are stored so we can replicate
the second lookup during instantiation.
In even simpler terms (paraphrasing the meeting minutes from the review of P1787; see https://wiki.edg.com/bin/view/Wg21summer2020/P1787%28Lookup%29Review2020-06-15Through2020-06-18):
- Unqualified lookup always happens for the first name in a
_nested-name-specifier_ that follows `.` or `->`
- The result of that lookup is only used to determine whether `<` is the
start of a _template-argument-list_ if the first (qualified) lookup
found nothing and the lookup context:
- is not dependent, or
- is the current instantiation and has no dependent base classes.
An example:
```
struct A
{
void f();
};
template<typename T>
using B = A;
template<typename T>
struct C : A
{
template<typename U>
void g();
void h(T* t)
{
this->g<int>(); // ok, '<' is the start of a template-argument-list ('g' was found via qualified lookup in the current instantiation)
this->B<void>::f(); // ok, '<' is the start of a template-argument-list (current instantiation has no dependent bases, 'B' was found via unqualified lookup)
t->g<int>(); // error: '<' means less than (unqualified lookup does not occur for a member-qualified name that isn't the first component of a nested-name-specifier)
t->B<void>::f(); // error: '<' means less than (unqualified lookup does not occur if the name is dependent)
t->template B<void>::f(); // ok: '<' is the start of a template-argument-list ('template' keyword used)
}
};
```
Some additional notes:
- Per [basic.lookup.qual.general] p1, lookup for a
member-qualified name only considers namespaces, types, and templates
whose specializations are types if it's an _identifier_ followed by
`::`; lookup for the component name of a _simple-template-id_ followed
by `::` is _not_ subject to this rule.
- The wording which specifies when the second unqualified lookup occurs
appears to be paradoxical. We are supposed to do it only for the first
component name of a _nested-name-specifier_ that follows `.` or `->`
when qualified lookup finds nothing. However, when that name is followed
by `<` (potentially starting a _simple-template-id_) we don't _know_
whether it will be the start of a _nested-name-specifier_ until we do
the lookup -- but we aren't supposed to do the lookup until we know it's
part of a _nested-name-specifier_! ***However***, since we only do the
second lookup when the first lookup finds nothing (and the name isn't
dependent), ***and*** since neither lookup is type-only, the only valid
option is for the name to be the _template-name_ in a
_simple-template-id_ that is followed by `::` (it can't be an
_unqualified-id_ naming a member because we already determined that the
lookup context doesn't have a member with that name). Thus, we can lock
into the _nested-name-specifier_ interpretation and do the second lookup
without having to know whether the _simple-template-id_ will be followed
by `::` yet.
This fixes#20777. This replaces #94216 which was reverted after being
merged.
Previously the `guarded_by`, `pt_guarded_by`, `acquired_after`, and
`acquired_before` attributes were only supported inside C++ classes or
top level C/C++ declaration.
This patch allows these attributes to be added to struct members in C.
These attributes have also now support experimental late parsing. This
is off by default but can be enabled by passing
`-fexperimental-late-parse-attributes`. This is useful for referring to
a struct member after the annotated member. E.g.
```
struct Example {
int a_value_defined_before __attribute__ ((guarded_by(a_mutex)));
struct Mutex *a_mutex;
};
```
Crashed when the number of args passed was less than number of
parameters in builtin definition, because we were indexing the list of
args while iterating through the entire number of parameters.
This patch moves documentation of `Sema` functions from `.cpp` files to `Sema.h` when there was no documentation in the latter, or it can be trivially subsumed. More complicated cases when there's less trivial divergence between documentation attached to declaration and the one attached to implementation are left for a later PR that would require review.
It appears that doxygen can find the documentation for a function defined out-of-line even if it's attached to an implementation, and not declaration. But other tools, e.g. clangd, are not as powerful. So this patch significantly improves autocompletion experience for (at least) clangd-based IDEs.
The lifetime bound warning in Clang currently only considers
initializations. This patch extends the warning to include assignments.
- **Support for assignments of built-in pointer types**: this is done is
by reusing the existing statement-local implementation. Clang now warns
if the pointer is assigned to a temporary object that being destoryed at
the end of the full assignment expression.
With this patch, we will detect more cases under the on-by-default
diagnostic `-Wdangling`. I have added a new category for this specific
diagnostic so that people can temporarily disable it if their codebase
is not yet clean.
This is the first step to address #63310, focusing only on pointer
types. Support for C++ assignment operators will come in a follow-up
patch.
Fixes#54492
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>
