Commit Graph

1455 Commits

Author SHA1 Message Date
Jay Foad
4dd55c567a [clang] Use {} instead of std::nullopt to initialize empty ArrayRef (#109399)
Follow up to #109133.
2024-10-24 10:23:40 +01:00
Younan Zhang
d15559d69d [Clang] Don't assert on substituted-but-yet-expanded packs for nested lambdas (#112896)
Nested lambdas could refer to outer packs that would be expanded by a
larger CXXFoldExpr, in which case that reference could happen to be a
full expression containing intermediate types/expressions, e.g.
SubstTemplateTypeParmPackType/FunctionParmPackExpr. They are designated
as "UnexpandedPack" dependencies but don't introduce new packs anyway.

This also handles a missed case for VarDecls, where the flag of
ContainsUnexpandedPack was not propagated up to the surrounding lambda.

Fixes #112352
2024-10-22 16:51:43 +08:00
Erich Keane
c8cbdc659c [OpenACC] Implement 'loop' 'vector' clause (#112259)
The 'vector' clause specifies the iterations to be executed in vector or
SIMD mode. There are some limitations on which associated compute
contexts may be associated with this and have arguments, but otherwise
this is a fairly unrestricted clause.

It DOES have region limits like 'gang' and 'worker'.
2024-10-15 06:12:19 -07:00
Erich Keane
cf456ed2a4 [OpenACC] implement loop 'worker' clause. (#112206)
The worker clause specifies iterations of the loop/ that are executed in
parallel by distributing the iterations among the multiple works within
a single gang.

The sema rules for this type are simply that it cannot be combined with
a `kernel` construct with a `num_workers` clause, child `loop` clauses
cannot contain a `gang` or `worker` clause, and that the argument is oly
allowed when associated with a `kernel`.
2024-10-14 09:08:24 -07:00
Erich Keane
5b25c31351 [OpenACC] Implement loop 'gang' clause. (#112006)
The 'gang' clause is used to specify parallel execution of loops, thus
has some complicated rules depending on the 'loop's associated compute
construct. This patch implements all of those.
2024-10-11 09:05:19 -07:00
Michael Kruse
5b03efb85d [Clang][OpenMP] Add permutation clause (#92030)
Add the permutation clause for the interchange directive which will be
introduced in the upcoming OpenMP 6.0 specification. A preview has been
published in
[Technical Report12](https://www.openmp.org/wp-content/uploads/openmp-TR12.pdf).
2024-10-09 14:56:43 +02:00
Oleksandr T.
41b09c5346 [Clang] omit parentheses in fold expressions with a single expansion (#110761)
Fixes #101863
2024-10-07 20:14:46 +02:00
Younan Zhang
8c1547055e [Clang] Remove the special-casing for RequiresExprBodyDecl in BuildResolvedCallExpr() after fd87d765c0 (#111277)
The special-casing for RequiresExprBodyDecl caused a regression, as
reported in #110785.

The original fix for #84020 has been superseded by fd87d765c0, which
establishes a `DependentScopeDeclRefExpr` instead of a
`CXXDependentScopeMemberExpr` for the case in issue. So the spurious
diagnostic in #84020 would no longer occur.

This also merges the test for #84020 together with that for #110785 into
clang/test/SemaTemplate/instantiate-requires-expr.cpp.

No release note because I think this merits a backport.

Fixes #110785
2024-10-07 09:38:19 +08:00
Erich Keane
d412cea8c4 [OpenACC] Implement 'tile' attribute AST (#110999)
The 'tile' clause shares quite a bit of the rules with 'collapse', so a
followup patch will add those tests/behaviors. This patch deals with
adding the AST node.

The 'tile' clause takes a series of integer constant expressions, or *.
The asterisk is now represented by a new OpenACCAsteriskSizeExpr node,
else this clause is very similar to others.
2024-10-03 08:34:43 -07:00
Erich Keane
da4b972ef6 [OpenACC] Enforce all 'collapse' intervening rules (#110684)
'collapse' makes the 'loop' construct apply to the next N nested loops,
and 'loop' requires all associated loops be 'for' loops (or range-for).

This patch adds this restriction, plus adds a number of infrastructure
changes to permit some of the other restrictions in the future to be
implemented.

'collapse' also requires that there is not any calls to other directives
 inside of the collapse region, so this also implements that limitation.
2024-10-02 07:10:53 -07:00
Erich Keane
97da34e015 [OpenACC] Add 'collapse' clause AST/basic Sema implementation (#109461)
The 'collapse' clause on a 'loop' construct is used to specify how many
nested loops are associated with the 'loop' construct. It takes an
optional 'force' tag, and an integer constant expression as arguments.

There are many other restrictions based on the contents of the loop/etc,
but those are implemented in followup patches, for now, this patch just
adds the AST node and does basic argument checking on the loop-count.
2024-10-01 06:40:21 -07:00
Sirraide
f4fa16f14b [Clang] Bugfixes and improved support for AttributedTypes in lambdas (#85325)
This fixes a crash when we attempt to instantiate a lambda with an
`AnnotatedType`, refactors the code that handles transforming the
function type of a lambda, and improves source fidelity for lambda
function types.

This fixes #85120 and fixes #85154.

---------

Co-authored-by: Yuxuan Chen <ych@meta.com>
Co-authored-by: Doug Wyatt <dwyatt@apple.com>
2024-09-26 03:24:53 +02:00
erichkeane
ebf1308674 [OpenACC] Ensure clause expressions side-effects don't happen
The OpenACC standard says side-effects/ordering of expressions in
clauses and constructs (not yet, but PR for constructs) cannot be
depended on.  We already had infrastructure to ensure constructs, and
non-template clauses did this right, but we had the ordering of a call
vs transform of the clauses happened in tree transform.

This patch ensures that the evaluation context put together for the
construct covers the clauses as well in tree transform.
2024-09-20 11:08:38 -07:00
Helena Kotas
0a7a1ef220 [HLSL] Add [[hlsl::contained_type()]] attribute (#108456)
Introducing a new HLSL resource type attribute `[[contained_type(T)]]`
which describes the "contained type" of a buffer or resource type.
Specifically, the attribute will be used on the resource handle in
templated buffer types like so:

template <typename T> struct RWBuffer {
  __hlsl_resource_t [[hlsl::contained_type(T)]] [[hlsl::resource_class(UAV)]] h;
};

Fixes #104855
2024-09-16 13:39:13 -07:00
Utkarsh Saxena
849d1b8b1f [clang] Do not substitute parameter pack while retaining the pack expansion (#108197)
(In reference to 5901d82ea0)
Consider when `Input[I]` is a `VarDecl` with parameter pack. We would
have already expanded the pack before the code change in the loop`for
(unsigned I = 0; I != *NumExpansions; ++I) {`.

Now in `if (RetainExpansion) {`, without this change, we continue to
substitute the pack in the pattern even when we do not have meaningful
`ArgumentPackSubstitutionIndex` set.

This leads to use of an invalid pack substitution index in
`TemplateInstantiator::TransformFunctionParmPackRefExpr` in
`TransformedDecl = (*Pack)[getSema().ArgumentPackSubstitutionIndex];`

This change sets `ArgumentPackSubstitutionIndex` to `-1` while retaining
expansion to instruct `TransformFunctionParmPackRefExpr` to build
`FunctionParmPackExpr` instead of substituting the param pack.

---

There are other instances of `RetainExpansion` and IIUC, they should
also unset the `ArgumentPackSubstitutionIndex`. It would be great if
someone can verify my understanding. If this is correct then we could
instead have a `ArgumentPackSubstitutionIndexRAII` as part of
`ForgetPartiallySubstitutedPackRAII`.

EDIT: I have moved this to `ForgetPartiallySubstitutedPackRAII`.

Fixes https://github.com/llvm/llvm-project/issues/63819
Fixes https://github.com/llvm/llvm-project/issues/107560
2024-09-12 13:21:26 +02:00
yronglin
060137038a Reapply "[Clang][CWG1815] Support lifetime extension of temporary created by aggregate initialization using a default member initializer" (#108039)
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>
2024-09-12 06:29:48 +08:00
Nikita Popov
3681d8552f Revert "[Clang][Sema] Use the correct lookup context when building overloaded 'operator->' in the current instantiation (#104458)"
This reverts commit 3cdb30ebbc.

Breaks clang bootstrap.
2024-09-09 21:10:12 +02:00
Krystian Stasiowski
3cdb30ebbc [Clang][Sema] Use the correct lookup context when building overloaded 'operator->' in the current instantiation (#104458)
Currently, clang erroneously rejects the following:
```
struct A
{
    template<typename T>
    void f();
};

template<typename T>
struct B
{
    void g()
    {
        (*this)->template f<int>(); // error: no member named 'f' in 'B<T>'
    }

    A* operator->();
};
```

This happens because `Sema::ActOnStartCXXMemberReference` does not adjust the `ObjectType` parameter when `ObjectType` is a dependent type (except when the type is a `PointerType` and the class member access is the `->` form). Since the (possibly adjusted) `ObjectType` parameter (`B<T>` in the above example) is passed to `Parser::ParseOptionalCXXScopeSpecifier`, we end up looking up `f` in `B` rather than `A`. 

This patch fixes the issue by identifying cases where the type of the object expression `T` is a dependent, non-pointer type and:
- `T` is the current instantiation and lookup for `operator->` finds a member of the current instantiation, or
- `T` has at least one dependent base case, and `operator->` is not found in the current instantiation

and using `ASTContext::DependentTy` as the type of the object expression when the optional _nested-name-specifier_ is parsed.

Fixes #104268.
2024-09-09 12:06:45 -04:00
Martin Storsjö
cca54e347a Revert "Reapply "[Clang][CWG1815] Support lifetime extension of temporary created by aggregate initialization using a default member initializer" (#97308)"
This reverts commit 45c8766973
and 049512e39d.

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.
2024-09-09 15:09:45 +03:00
yronglin
45c8766973 Reapply "[Clang][CWG1815] Support lifetime extension of temporary created by aggregate initialization using a default member initializer" (#97308)
The PR reapply https://github.com/llvm/llvm-project/pull/92527.
Implemented CWG1815 and fixed the bugs mentioned in the comments of
https://github.com/llvm/llvm-project/pull/92527 and
https://github.com/llvm/llvm-project/pull/87933.

The reason why the original PR was reverted was that errors might occur
during the rebuild.

---------

Signed-off-by: yronglin <yronglin777@gmail.com>
2024-09-08 22:36:49 +08:00
Helena Kotas
8e35c86977 [HLSL] Apply resource attributes to the resource type rather than the handle member (#107160)
Converts existing resource attributes `[[hlsl::resource_class(..)]]` and
`[[is_rov]]` from declaration attributes to type attributes.

During type attribute processing all HLSL resource type attributes are
validated and collected by `SemaHLSL`
(`SemaHLSL::handleResourceTypeAttr`). At the end of the declaration they
are be combined into a single `HLSLAttributedResourceType` instance
(`SemaHLSL::ProcessResourceTypeAttributes`) that wraps the original type
and stores all of the necessary information about the resource.

`SemaHLSL` will also need to short-term-store the `TypeLoc` information
for the newly created type that will be grabbed by `TypeSpecLocFiller`
soon after it is created.

Updates all places that expected resource attributes on declarations
like resource binding diagnostic, builtin types in
HLSLExternalSemaSource, or codegen.

Also includes implementation of
`TreeTransform<Derived>::TransformHLSLAttributedResourceType` that
enables the use of attributed resource types inside templates.

Fixes #104861
Part 2/2
2024-09-05 21:50:00 -07:00
Younan Zhang
aacdc657fc [Clang] Preserve the ExpandsToEmpty flag in PackIndexingType (#107181)
Similar to PackIndexingExpr, we should avoid another round of
transformation of the pattern if the pattern has already turned out to
be an empty pack. As an outcome, the empty SubstTemplateTypeParmPackType
won't occur, and we don't need to collect any unexpanded packs.

Fixes https://github.com/llvm/llvm-project/issues/105903
2024-09-04 16:34:27 +08:00
Chris B
89fb8490a9 [HLSL] Implement output parameter (#101083)
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>
2024-08-31 10:59:08 -05:00
Helena Kotas
e00e9a3f82 [HLSL] Add HLSLAttributedResourceType (#106181)
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
2024-08-29 21:42:20 -07:00
cor3ntin
5a288b9183 [Clang] Evaluate dependent indexes of pack indexing in a constant context (#106054)
Fixes #105900
2024-08-26 17:50:32 +02:00
Shilei Tian
aa86e5beff [Clang][OpenMP] Fix the wrong transform of num_teams claused introduced in #99732 (#102716) 2024-08-12 08:57:37 -04:00
Shilei Tian
1c269929d0 [Clang][Sema][OpenMP] Allow thread_limit to accept multiple expressions (#102715) 2024-08-10 09:54:58 -04:00
Sirraide
8dfa651a63 [Clang] Fix crash when transforming a DependentAddressSpaceType (#102206)
We were forgetting to pass the `TypeLocBuilder` along to
`TransformType`, causing us to complain if we then tried to build a
`DependentAddressSpaceTypeLoc` because the inner `TypeLoc` was 
missing from the TLB.

Fixes #101685.
2024-08-07 02:37:29 +02:00
Krystian Stasiowski
55ea36002b [Clang][Sema] Make UnresolvedLookupExprs in class scope explicit specializations instantiation dependent (#100392)
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.
2024-08-06 12:40:44 -04:00
Shilei Tian
cee594cf36 [Clang][Sema][OpenMP] Allow num_teams to accept multiple expressions (#99732)
By the OpenMP standard, `num_teams` clause can only accept one
expression (for now). In this patch, we extend it to allow to accept
multiple expressions when it is used with `target teams ompx_bare`
construct. This will allow to launch a multi-dim grid, same as CUDA/HIP.
2024-08-06 10:55:15 -04:00
Younan Zhang
874067a22f [Sema] Preserve ContainsUnexpandedParameterPack in TransformLambdaExpr (#86265)
The lambda `ContainsUnexpandedParameterPack` flag is used for the
expressions' dependency computing and is therefore essential for pack
expansion. We previously lost the flag's preservation during the
lambda's transform, which caused some issues, e.g. a fold expression
couldn't properly expand inside a template.

This patch alleviates the issue by retaining the flag in more scenarios.
Note that we still have problems with constraints involving packs
regarding lambdas, and dealing with that would take more effort, and
we'd like to fix them in the future.

Fixes https://github.com/llvm/llvm-project/issues/56852
Fixes https://github.com/llvm/llvm-project/issues/85667
Mitigates https://github.com/llvm/llvm-project/issues/99877 because the
attributes were not handled in this patch.

---------

Co-authored-by: Ilya Biryukov <809452+ilya-biryukov@users.noreply.github.com>
Co-authored-by: cor3ntin <corentinjabot@gmail.com>
2024-08-06 10:54:45 +08:00
Julian Brown
a42e515e3a [OpenMP] OpenMP 5.1 "assume" directive parsing support (#92731)
This is a minimal patch to support parsing for "omp assume" directives.
These are meant to be hints to a compiler's optimisers: as such, it is
legitimate (if not very useful) to ignore them. The patch builds on top
of the existing support for "omp assumes" directives (note spelling!).

Unlike the "omp [begin/end] assumes" directives, "omp assume" is
associated with a compound statement, i.e. it can appear within a
function. The "holds" assumption could (theoretically) be mapped onto
the existing builtin "__builtin_assume", though the latter applies to a
single point in the program, and the former to a range (i.e. the whole
of the associated compound statement).

This patch fixes sollve's OpenMP 5.1 "omp assume"-based tests.
2024-08-05 07:37:07 -04:00
Mital Ashok
7536ebf0ea [Clang][SemaCXX] Fix bug where unexpanded lambda captures where assumed to have size 1 (#101385)
Fixes #63677
2024-08-05 16:16:55 +08:00
Krzysztof Parzyszek
243b27f7e1 [clang][OpenMP] Rename varlists to varlist, NFC (#101058)
It returns a range of variables (via Expr*), not a range of lists.
2024-07-30 08:11:09 -05:00
Krzysztof Parzyszek
c74730070a [clang][OpenMP] Move "loop" directive mapping from sema to codegen (#99905)
Given "loop" construct, clang will try to treat it as "for",
"distribute" or "simd", depending on either the implied binding, or the
bind clause if present. This patch moves the code that performs this
construct remapping from sema to codegen.

For a "loop" construct without a bind clause, this patch will create an
implicit bind clause based on implied binding to simplify further
analysis.

During codegen the function `EmitOMPGenericLoopDirective` (i.e. "loop")
will invoke the "emit" functions for "for", "distribute" or "simd",
depending on the bind clause.

---------

Co-authored-by: Alexey Bataev <a.bataev@gmx.com>
2024-07-23 07:31:42 -05:00
Michael Kruse
5c93a94f5a [Clang][OpenMP] Add interchange directive (#93022)
Add the interchange directive which will be introduced in the upcoming
OpenMP 6.0 specification. A preview has been published in [Technical
Report 12](https://www.openmp.org/wp-content/uploads/openmp-TR12.pdf).
2024-07-19 09:24:40 +02:00
Michael Kruse
80865c01e1 [Clang][OpenMP] Add reverse directive (#92916)
Add the reverse directive which will be introduced in the upcoming
OpenMP 6.0 specification. A preview has been published in [Technical
Report 12](https://www.openmp.org/wp-content/uploads/openmp-TR12.pdf).

---------

Co-authored-by: Alexey Bataev <a.bataev@outlook.com>
2024-07-18 10:35:32 +02:00
smanna12
ca61bdde47 [Clang] Prevent null pointer dereference in TransformUnaryTransformType() (#97912)
This patch adds null check after TransformType call to avoid
dereferencing a null pointer when calling getType().
2024-07-16 12:24:57 -05:00
Haojian Wu
59e56eeb1d Revert "Reapply "[Clang] Implement resolution for CWG1835 (#92957)" (#98547)"
This reverts commit ce4aada6e2 and a
follow-up patch 8ef26f1289.

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
2024-07-15 13:22:40 +02:00
Krystian Stasiowski
ce4aada6e2 Reapply "[Clang] Implement resolution for CWG1835 (#92957)" (#98547)
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.
2024-07-11 18:49:35 -04:00
NAKAMURA Takumi
d3923354a4 Revert "[Clang] Implement resolution for CWG1835 (#92957)"
ppc64le-lld-multistage-test has been failing.

This reverts commit 7bfb98c346.
2024-07-10 13:50:34 +09:00
Krystian Stasiowski
7bfb98c346 [Clang] Implement resolution for CWG1835 (#92957)
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.
2024-07-09 19:00:19 -04:00
Henrik G. Olsson
e22ebee5a3 [Bounds-Safety] Add sized_by, counted_by_or_null & sized_by_or_null (#93231)
The attributes `sized_by`, `counted_by_or_null` and `sized_by_or_null`
have been added as variants on `counted_by`, each with slightly
different semantics. `sized_by` takes a byte size parameter instead of
an element count, allowing pointees with unknown size. The
`counted_by_or_null` and `sized_by_or_null` variants are equivalent to
their base variants, except the pointer can be null regardless of
count/size value. If the pointer is null the size is effectively 0.

rdar://125400354
2024-07-09 13:58:01 -07:00
Krystian Stasiowski
dfc8004d0b [Clang][Sema] Fix crash when rebuilding MemberExprs with invalid object expressions (#97455)
This patch fixes an assertion failure which occurs when the object expression of a `MemberExpr` is transformed into an expression with a dependent type for which the `DeclContext` cannot be computed (e.g. a `RecoveryExpr`). Fixes #95778.
2024-07-09 13:30:55 -04:00
Krystian Stasiowski
10b43f429a [Clang][Sema] Correctly transform dependent operands of overloaded binary operator& (#97596)
Currently, `TreeTransform::TransformCXXOperatorCallExpr` calls
`TreeTransform::TransformAddressOfOperand` to transform the first
operand of a `CXXOperatorCallExpr` when its `OverloadOperatorKind` is
`OO_Amp` -- regardless of arity. This results in the first operand of
binary `operator&` being incorrectly transformed as if it was the
operand of the address of operator in cases such as the following:
```
struct A {
  int x;
};

void operator&(A, A);

template<typename T>
struct B {
  int f() {
    return T::x & 1; // invalid reference to 'A::x' is not diagnosed because 'T::x' is incorrectly transformed as if it was the operand of unary operator&
  }
};

template struct B<A>;
```
Prior to #92318 we would build a `CXXDependentScopeMemberExpr` for
`T::x` (as with most dependent qualified names that were not member
qualified names). Since `TreeTransform::TransformAddressOfOperand` only
differs from `TransformExpr` for `DependentScopeDeclRefExpr` and
`UnresolvedLookupExpr` operands, `T::x` was transformed "correctly". Now
that we build a `DependentScopeDeclRefExpr` for `T::x`, it is
incorrectly transformed as if it was the operand of the address of
operator and we fail to diagnose the invalid reference to a non-static
data member. This patch fixes the issue by only calling
`TreeTransform::TransformAddressOfOperand` for `CXXOperatorCallExpr`s
with a single operand. This fixes #97483.
2024-07-03 18:19:58 -04:00
Simon Pilgrim
4d167fb28b [Sema] TransformTypeOfExprType / TransformTypeOfType - don't dereference getAs<> results
Use castAs<> to assert the cast is valid to help avoid null dereferences

Fixes static analyser warnings
2024-06-27 13:09:48 +01:00
Doug Wyatt
f03cb005eb [Clang] Introduce nonblocking/nonallocating attributes (#84983)
Introduce `nonblocking` and `nonallocating` attributes. RFC is here:
https://discourse.llvm.org/t/rfc-nolock-and-noalloc-attributes/76837

This PR introduces the attributes, with some changes in Sema to deal
with them as extensions to function (proto)types.

There are some basic type checks, most importantly, a warning when
trying to spoof the attribute (implicitly convert a function without the
attribute to one that has it).

A second, follow-on pull request will introduce new caller/callee
verification.
---------
Co-authored-by: Doug Wyatt <dwyatt@apple.com>
Co-authored-by: Shafik Yaghmour <shafik.yaghmour@intel.com>
Co-authored-by: Aaron Ballman <aaron@aaronballman.com>
Co-authored-by: Sirraide <aeternalmail@gmail.com>
2024-06-24 12:51:31 +02:00
Mariya Podchishchaeva
41c6e43792 Reland [clang][Sema, Lex, Parse] Preprocessor embed in C and C++ (#95802)
This commit implements the entirety of the now-accepted [N3017
-Preprocessor
Embed](https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3017.htm) and
its sister C++ paper [p1967](https://wg21.link/p1967). It implements
everything in the specification, and includes an implementation that
drastically improves the time it takes to embed data in specific
scenarios (the initialization of character type arrays). The mechanisms
used to do this are used under the "as-if" rule, and in general when the
system cannot detect it is initializing an array object in a variable
declaration, will generate EmbedExpr AST node which will be expanded by
AST consumers (CodeGen or constant expression evaluators) or expand
embed directive as a comma expression.

This reverts commit
682d461d5a.

---------

Co-authored-by: The Phantom Derpstorm <phdofthehouse@gmail.com>
Co-authored-by: Aaron Ballman <aaron@aaronballman.com>
Co-authored-by: cor3ntin <corentinjabot@gmail.com>
Co-authored-by: H. Vetinari <h.vetinari@gmx.com>
2024-06-20 14:38:46 +02:00
cor3ntin
3417ff6b1c [Clang] Fix immediate escalation in templated entities (#95233)
* Lambdas were not considered immediate escalating in a template
* Calls to an immediate function whose arguments were dependent were
incorrectly treated as immediate escalating.

Fixes #94935
2024-06-18 15:40:25 +02:00
Vitaly Buka
682d461d5a Revert " [Sema, Lex, Parse] Preprocessor embed in C and C++ (and Obj-C and Obj-C++ by-proxy)" (#95299)
Reverts llvm/llvm-project#68620

Introduce or expose a memory leak and UB, see llvm/llvm-project#68620
2024-06-12 13:14:26 -07:00