The infrastructure in semantics that is used to check that the
left-hand sides of normal assignment statements are really definable
variables was not being used to check whether the LHSs of pointer assignments
are modifiable, and so most cases of unmodifiable pointers are left
undiagnosed. Rework the semantics checking for pointer assignments,
NULLIFY statements, pointer dummy arguments, &c. so that cases of
unmodifiable pointers are properly caught. This has been done
by extracting all the various definability checking code that has
been implemented for different contexts in Fortran into one new
facility.
The new consolidated definability checking code returns messages
meant to be attached as "because: " explanations to context-dependent
errors like "left-hand side of assignment is not definable".
These new error message texts and their attached explanations
affect many existing tests, which have been updated. The testing
infrastructure was extended by another patch to properly compare
warnings and explanatory messages, which had been ignored until
recently.
Differential Revision: https://reviews.llvm.org/D136979
Add the atomic subroutine, atomic_cas, to the list of intrinsic
subroutines and check one of its arguments for a coindexed object.
Create a new function, CheckAtomicKind, that will be used for the
atomic subroutines that have arguments that can be either of type
int and of kind atomic_int_kind or of type logical and of kind
atomic_logical_kind.
Reviewed By: jeanPerier
Differential Revision: https://reviews.llvm.org/D135835
