Again, this simplifies the semantic checks and lowering quite a bit.
Update the check for positive alignment to use a more informative
message, and to highlight the modifier itsef, not the whole clause.
Remove the checks for the allocator expression itself being positive:
there is nothing in the spec that says that it should be positive.
Remove the "simple" modifier from the AllocateT template, since both
simple and complex modifiers are the same thing, only differing in
syntax.
This removes the specialized parsers and helper classes for these
clauses, namely ConcatSeparated, MapModifiers, and MotionModifiers. Map
and the motion clauses are now handled in the same way as all other
clauses with modifiers, with one exception: the commas separating their
modifiers are optional. This syntax is deprecated in OpenMP 5.2.
Implement version checks for modifiers: for a given modifier on a given
clause, check if that modifier is allowed on this clause in the
specified OpenMP version. This replaced several individual checks.
Add a testcase for handling map modifiers in a different order, and for
diagnosing an ultimate modifier out of position.
This actually simplifies the AST node for the schedule clause: the two
allowed modifiers can be easily classified as the ordering-modifier and
the chunk-modifier during parsing without the need to create additional
classes.
Also, define helper macros in parse-tree.h.
Apply the new modifier representation to the DEFAULTMAP and REDUCTION
clauses, with testcases utilizing the new modifier validation.
OpenMP modifier overhaul: #3/3
The main issue to solve is that OpenMP modifiers can be specified in any
order, so the parser cannot expect any specific modifier at a given
position. To solve that, define modifier to be a union of all allowable
specific modifiers for a given clause.
Additionally, implement modifier descriptors: for each modifier the
corresponding descriptor contains a set of properties of the modifier
that allow a common set of semantic checks. Start with the syntactic
properties defined in the spec: Required, Unique, Exclusive, Ultimate,
and implement common checks to verify each of them.
OpenMP modifier overhaul: #2/3
