Invent `StylizedInstance` class to store special variables together with
the instantiated expression in omp::clause::Initializer. This will
eliminate the need for visiting the original AST nodes in lowering to
MLIR.
Move `GetInnermostExecPart` and `IsStrictlyStructuredBlock` from
Semantics/openmp-utils.* to Parser/openmp-utils.*. These two only depend
on the AST contents and properties.
For ALLOCATORS and executable ALLOCATE first perform list item checks in
the context of an individual ALLOCATE clause or directive respectively,
then perform "global" checks, e.g. whether all list items are present on
the ALLOCATE statement.
These changes allowed to simplify the checks for presence on ALLOCATE
statement and the use of a predefined allocator.
Additionally, allow variable list item lists to be empty, add a test for
the related spec restriction.
This is a first step towards unifying OpenMPDeclarativeAllocate and
OpenMPExecutableAllocate into a single directive.
OpenMP 5.0 and 5.1 allowed the ALLOCATE directive to appear in two
forms, declarative and executable. The syntax of an individual directive
was the same in both cases, but the semantic restrictions were slightly
different.
- Update the semantic checks to reflect the different restrictions,
gather them in a single function.
- Improve test for the presence of a TARGET region, add a check for
REQUIRES directive.
- Update tests.
REQUIRES clauses apply to the compilation unit, which the OpenMP spec
defines as the program unit in Fortran.
Don't set REQUIRES flags on all containing scopes, only on the containng
program unit, where flags coming from different directives are gathered.
If we wanted to set the flags on subprograms, we would need to first
accummulate all of them, then propagate them down to all subprograms.
That is not done as it is not necessary (the containing program unit is
always available).
This verifies the "structural" restrictions on constructs encountered in
a TASKGRAPH construct.
There are also restrictions that apply to list items, specifically in
the following contexts:
- a list item on a clause on a replayable construct,
- data-sharing attributes for a variable on a replayable construct.
These restrictions are not verified, because that would require knowing
which clauses (on a potential compound directive) apply to the task-
generating construct of interest. This information is not available
during semantic checks.
Since ODS doesn't store a list of OmpObjects (i.e. not as
OmpObjectList), some semantics-checking functions needed to be updated
to operate on a single object at a time.
An error report of the following code generating non-atomic code led us
to realize there are missing checks in the OpenACC atomics code. Add
some of those checks for atomic and sketch how the rest of the code
should proceed in checking the rest of the properties. The following
cases are all reported as errors.
```fortran
! Originally reported error!
!$acc atomic capture
a = b
c = b
!$acc end atomic capture
! Other ambiguous, but related errors!
!$acc atomic capture
x = i
i = x
!$acc end atomic capture
!$acc atomic capture
a = b
b = b
!$acc end atomic capture
!$acc atomic capture
a = b
a = c
!$acc end atomic capture
```
OpenMP 6.0 has changed the modifiers on the MAP clause. Previous patch
has introduced parsing support for them. This patch introduces
processing of the new forms in semantic checks and in lowering. This
only applies to existing modifiers, which were updated in the 6.0 spec.
Any of the newly introduced modifiers (SELF and REF) are ignored.
The ALLOCATORS construct is one of the few constructs that require a
special form of the associated block.
Convert the AST node to use OmpDirectiveSpecification for the directive
and the optional end directive, and to use parser::Block as the body:
the form of the block is checked in the semantic checks (with a more
meaningful message).
Create these new files in flang/lib/Semantics:
openmp-utils.cpp/.h - Common utilities
check-omp-atomic.cpp - Atomic-related checks
check-omp-loop.cpp - Loop constructs/clauses
check-omp-metadirective.cpp - Metadirective-related checks
Update lists of included headers, std in particular.
---------
Co-authored-by: Jack Styles <jack.styles@arm.com>
