When an ELEMENTAL subroutine is erroneously declared with alternate return
arguments, don't crash when checking the ranks of the actual arguments.
Differential Revision: https://reviews.llvm.org/D140143
This patch implements @klausler's suggestion in `llvm-project` [issue #58973](https://github.com/llvm/llvm-project/issues/58973); encountering the `VOLATILE` attribute should produce a __warning__, not a __fatal error__.
When tested on the following Fortran program `snem0601_012_.f90`:
```fortran
module mod
contains
subroutine sub(m6,error)
integer,intent(inout) :: error
integer,volatile :: m6
if (any ((/m6/).ne.(/6/))) &
& then
error = 1
end if
end subroutine
end module
program fe1nvol12
use mod
integer :: error = 0
call sub(6,error)
if (error .ne. 0) then
print *,'NG: snem0601_012'
end if
print *,'pass: snem0601_012'
end program fe1nvol12
```
the following output is produced:
```bash
$ flang-new -fc1 snem0601_012_.f90
/noback/93u/Sandbox/issue_58973_volatile_dummy_arg/snem0601_012_.f90:21:12: warning: actual argument associated with VOLATILE dummy argument 'm6=' is not a variable
call sub(6,error)
^
```
Reviewed By: clementval, klausler
Differential Revision: https://reviews.llvm.org/D139134
Enforce detectable compilation-time violations of restrictions on the
arguments to the TRANSFER() intrinsic function (16.9.163) with
error messages, and mark other potential problems with warnings.
Differential Revision: https://reviews.llvm.org/D139157
19.6.8 forbids using an INTENT(IN) pointer dummy argument in a pointer association
context, and associated such a pointer with a dummy argument of INTENT(IN OUT) or
INTENT(OUT) is a circumstance that needs to be caught as an error.
Differential Revision: https://reviews.llvm.org/D139138
Standard Fortran allows type-bound procedure bindings to only
be called, and disallows them from being used in other contexts
where a procedure name can be: as the target of a procedure pointer
assignment statement, and as an actual argument that corresponds
to a dummy procedure. So long as the interfaces match, there's
no good reason for these uses to be errors, and there some obvious
use cases in polymorphic programming. So emit portability warnings
rather than errors, and document this usage as an extension.
Differential Revision: https://reviews.llvm.org/D139127
Definability checking is unconditionally flagging the use of a polymorphic
variable as an actual argument for a procedure reference in a PURE subprogram
unless the corresponding dummy is INTENT(IN). This isn't necessary, since
an INTENT(OUT) polymorphic dummy is already caught as an error in the definition
of the callee, which must also be PURE; and an INTENT(IN OUT) or intent-free
dummy is allowed to be passed a polymorphic actual in a PURE context, with
any attempt to deallocate it being caught in the callee.
So add a flag to the definability checker to disable the "polymorphic
definition in PURE context" check when using it to check actual arguments.
Differential Revision: https://reviews.llvm.org/D139044
When a scope declares the name and perhaps some characteristics of
an external subprogram using any of the many means that Fortran supplies
for doing such a thing, and that external subprogram's definition is
available, check the local declaration against the external definition.
In particular, if the global definition's interface cannot be called
by means of an implicit interface, ensure that references are via an
explicit and compatible interface.
Further, extend call site checking so that when a local declaration
exists for a known global symbol and the arguments are valid for that
local declaration, the arguments are checked against the global's
interface, just are is already done when no local declaration exists.
Differential Revision: https://reviews.llvm.org/D139042
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
Some of the circumstances that require that a procedure have an
explicit interface at a point of call due to a characteristic of
a dummy argument apply to dummy procedures, too.
Differential Revision: https://reviews.llvm.org/D136994
When a dummy argument is a procedure pointer without INTENT(IN),
any actual argument must also be a procedure pointer, whether the
dummy procedure pointer's interface is explicit or not.
Differential Revision: https://reviews.llvm.org/D136989
The code snippet
module m
interface
module subroutine specific
end subroutine
end interface
interface generic
module procedure specific
end interface
end module
elicits a bogus semantic error about "specific" not being an acceptable
module procedure for the generic interface; fix.
Differential Revision: https://reviews.llvm.org/D134402
A NULL() pointer is a valid actual argument for a procedure pointer dummy
argument whose intent is INTENT(IN); it should also be acceptable for a
procedure pointer dummy argument with unspecified intent.
Also make it possible to discern null object pointers from null procedure
pointers, so that an attempt to use one in place of the other in a context
where the distinction matters will still elicit an error.
Differential Revision: https://reviews.llvm.org/D132687
Semantic checking for calls was requiring an actual argument that corresponds
to an ASYNCHRONOUS or VOLATILE dummy argument to be definable, but this is not
a constraint or requirement in the standard and doesn't even make sense
as a warning; these two attributes are "scopable" in the context of BLOCK
constructs. Remove the checks and adjust the tests.
Differential Revision: https://reviews.llvm.org/D132684
The predicate "CanBeCalledViaImplicitInterface()" was returning false for
restricted specific intrinsic functions (e.g., SIN) because their procedure
characteristics have the elemental attribute; this leads to a bogus semantic
error when one attempts to use them as proc-targets in procedure pointer
assignment statements when the left-hand side of the assignment is a procedure
pointer with an implicit interface. However, these restricted specific intrinsic
functions have always been allowed as special cases for such usage -- it is
as if they are elemental when it is necessary for them to be so, but not
when it's a problem.
Differential Revision: https://reviews.llvm.org/D130386
f18 intentionally does not support the spottily-implemented language extension
in which one can pass NULL() for an allocatable dummy argument. This is perhaps
a sanctioned side effect in other compilers of the fact that they pass distinct
"base address" and "descriptor address" physical arguments.
Make the error message in this case more specific to the circumstances, and
add a note to Extensions.md to clarify that this behavior is intended.
(We could, with some effort in lowering, support passing NULL for an INTENT(IN)
allocatable dummy, but let's see whether such nonconforming usage appears
in a real application before spending any more time on it.)
Differential Revision: https://reviews.llvm.org/D130380
Some procedure pointers and EXTERNAL procedures have neither
explicit interfaces nor result types; these procedures are obviously
not known to be functions, but they could be, so semantics must not
assume that they are necessarily subroutines. Refine the procedure
pointer / dummy procedure compatibility check to handle these more
ambiguous cases and not elicit inappropriate error messages.
Differential Revision: https://reviews.llvm.org/D129674
When a Hollerith (or short character) literal is presented as an actual
argument that corresponds to a dummy argument for which a BOZ literal
would be acceptable, treat the Hollerith as if it had been a BOZ
literal in the same way -- and with the same code -- as f18 already
does for the similar extension in DATA statements.
Differential Revision: https://reviews.llvm.org/D126144
As Fortran 2018 15.8.1(3), in a reference to an elemental procedure, if
any argument is an array, each actual argument that corresponds to an
INTENT (OUT) or INTENT (INOUT) dummy argument shall be an array. Add
this semantic check.
Reviewed By: klausler
Differential Revision: https://reviews.llvm.org/D125685
A disassociated procedure pointer is allowed to be passed as an absent
actual argument that corresponds to an optional dummy procedure,
but not NULL(); accept that case as well.
Differential Revision: https://reviews.llvm.org/D125127
Actual arguments whose lengths are less than the expected length
of their corresponding dummy argument are errors; but this needs
to be refined. Short actual arguments that are variables remain
errors, but those that are expressions can be (again) extended on
the right with blanks.
Differential Revision: https://reviews.llvm.org/D125115
When we pass an alternate return specifier to a regular (not an asterisk)
dummy argument, flang would throw an internal compiler error of
derefencing a null pointer.
To avoid the ICE, a check was added.
Reviewed By: kiranchandramohan
Differential Revision: https://reviews.llvm.org/D123947
As Fortran 2018 C1533, a nonintrinsic elemental procedure shall not be
used as an actual argument. The semantic check for implicit iterface is
missed.
Reviewed By: klausler
Differential Revision: https://reviews.llvm.org/D124379
Adds flang/include/flang/Common/log2-visit.h, which defines
a Fortran::common::visit() template function that is a drop-in
replacement for std::visit(). Modifies most use sites in
the front-end and runtime to use common::visit().
The C++ standard mandates that std::visit() have O(1) execution
time, which forces implementations to build dispatch tables.
This new common::visit() is O(log2 N) in the number of alternatives
in a variant<>, but that N tends to be small and so this change
produces a fairly significant improvement in compiler build
memory requirements, a 5-10% improvement in compiler build time,
and a small improvement in compiler execution time.
Building with -DFLANG_USE_STD_VISIT causes common::visit()
to be an alias for std::visit().
Calls to common::visit() with multiple variant arguments
are referred to std::visit(), pending further work.
This change is enabled only for GCC builds with GCC >= 9;
an earlier attempt (D122441) ran into bugs in some versions of
clang and was reverted rather than simply disabled; and it is
not well tested with MSVC. In non-GCC and older GCC builds,
common::visit() is simply an alias for std::visit().
f18 was emitting a warning about short character actual arguments to
subprograms and statement functions; every other compiler considers this
case to be an error.
Differential Revision: https://reviews.llvm.org/D123731
Error messages can have a list of attachments; these are used to point
to related source locations, supply additional information, and to
encapsulate error messages that were *not* emitted in a given context
to explain why a warning was justified.
This patch adds a message severity ("Because") for that last case,
and extends to AttachTo() API to provide a means for overriding
the severity of an attached message.
Some existing message attachments had their severities adjusted,
now that we're printing them. And operator==() for Message was
cleaned up while debugging after I noticed that it was recursively
O(N**2) and subject to returning a false positive.
Differential Revision: https://reviews.llvm.org/D123710
The actual argument shall have deferred the same type parameters as
the dummy argument if the argument is allocatable or pointer variable.
Currently programs not following this get one crash during execution.
Reviewed By: Jean Perier
Differential Revision: https://reviews.llvm.org/D122779
Previously, some semantic checks that are checking if an entity is an
allocatable were relying on the expression being a designator whose
last symbol has the allocatable attribute.
This is wrong since this was considering substrings and array sections of
allocatables as being allocatable. This is wrong (see NOTE 2 in
Fortran 2018 section 9.5.3.1).
Add evaluate::IsAllocatableDesignator to correctly test this.
Also add some semantic tests for ALLOCATED to test the newly added helper.
Note that ifort and nag are rejecting coindexed-named-object in
ALLOCATED (`allocated(coarray_scalar_alloc[2])`).
I think it is wrong given allocated argument is intent(in) as per
16.2.1 point 3.
So 15.5.2.6 point 4 regarding allocatable dummy is not violated (If the actual
argument is a coindexed object, the dummy argument shall have the INTENT (IN)
attribute.) and I think this is valid. gfortran accepts it.
The need for this helper was exposed in https://reviews.llvm.org/D122779.
Differential Revision: https://reviews.llvm.org/D122899
Co-authored-by: Peixin-Qiao <qiaopeixin@huawei.com>
Adds flang/include/flang/Common/visit.h, which defines
a Fortran::common::visit() template function that is a drop-in
replacement for std::visit(). Modifies most use sites in
the front-end and runtime to use common::visit().
The C++ standard mandates that std::visit() have O(1) execution
time, which forces implementations to build dispatch tables.
This new common::visit() is O(log2 N) in the number of alternatives
in a variant<>, but that N tends to be small and so this change
produces a fairly significant improvement in compiler build
memory requirements, a 5-10% improvement in compiler build time,
and a small improvement in compiler execution time.
Building with -DFLANG_USE_STD_VISIT causes common::visit()
to be an alias for std::visit().
Calls to common::visit() with multiple variant arguments
are referred to std::visit(), pending further work.
Differential Revision: https://reviews.llvm.org/D122441
evaluate::IsPointerObject used to return true for pointer suboject like
`pointer(10)` while these object are not pointers. This prevented some
checks like 15.5.2.7 to be correctly enforced (e.g., it was possible to
pass `pointer(10)` to a non intent(in) dummy pointer).
After updating IsPointerObject behavior and adding a test for 15.5.2.7 in
call07.f90, a test in call03.f90 for 15.5.2.4(14) was failing.
It appeared the related semantics check was relying on IsPointerObject
to return true for `pointer(10)`. Adapt the code to detect pointer element
in another way.
While looking at the code, I also noticed that semantics was
rejecting `character(1)` pointer/assumed shape suboject when these are
allowed (the standard has a special case for character(1) in
15.5.2.4(14), and I verified that other compilers that enforce 15.5.2.4(14)
do accept this).
Differential Revision: https://reviews.llvm.org/D121377
Using recently established message severity codes, upgrade
non-fatal messages to usage and portability warnings as
appropriate.
Differential Revision: https://reviews.llvm.org/D121246
Add new IsCompatibleWith() member functions to many classes in evaluate::characteristics
that apply more nuanced compatibility checking for function results, dummy
arguments, and procedure interfaces than the previous tests for complete
equivalence. Use IsCompatibleWith() in semantics for call checking.
Differential Revision: https://reviews.llvm.org/D120844
An assumed-type actual argument that corresponds to an assumed-rank dummy
argument shall be assumed-shape or assumed-rank.
Differential Revision: https://reviews.llvm.org/D120750
Track source location information when available for actual arguments
to procedure references, and use this information when checking constraints
on calls so that error messages refer to specific actual arguments
rather than to the entire call.
Differential Revision: https://reviews.llvm.org/D119849
Consistent with previously documented policy, in which
BOZ literals are accepted in non-standard-conforming circumstances
where they can be converted to an unambiguous known numeric type,
allow BOZ literals to be passed as an actual argument in a reference
to a procedure whose explicit interface has a corresponding dummy
argument with a numeric type to which the BOZ literal may be
converted. Improve error messages associated with BOZ literal
actual arguments, too: don't emit multiple errors.
Differential Revision: https://reviews.llvm.org/D117698
Some kinds of Fortran arrays are declared with the same syntax,
and it is impossible to tell from a shape (:, :) or (*) whether
the object is assumed shape, deferred shape, assumed size, implied
shape, or whatever without recourse to more information about the
symbol in question. This patch softens the names of some predicate
functions (IsAssumedShape to CanBeAssumedShape) and makes others
more reflective of the syntax they represent (isAssumed to isStar)
in an attempt to encourage coders to seek and find definitive
predicate functions whose names deliver what they seem to mean.
Address TODO comments in IsSimplyContiguous() by using the
updated IsAssumedShape() predicate.
Differential Revision: https://reviews.llvm.org/D114829
Don't try to convert INTEGER argument expressions to the kind of
the dummy argument when performing generic resolution; specific
procedures may be distinguished only by their kinds.
Differential Revision: https://reviews.llvm.org/D112240
Catch additional missing error cases for typed and untyped
NULL actual arguments to non-intrinsic procedures in cases
of explicit and implicit interfaces.
Differential Revision: https://reviews.llvm.org/D110003
A procedure actual argument to a PURE procedure should be required
to have an explicit interface. Implicit-interface actual arguments
to non-PURE procedures remain a warning.
Differential Revision: https://reviews.llvm.org/D109926
When the shapes of actual arguments to ELEMENTAL procedures are
sufficiently well known during semantics, require them to conform.
Differential Revision: https://reviews.llvm.org/D109909
Improve checking for NULL() and NULL(MOLD=) when used as
variables and expressions outside the few contexts where
a disassociated pointer can be valid. There were both
inappropriate errors and missing checks.
Differential Revision: https://reviews.llvm.org/D109905
It may not be great practice to pass a procedure (or procedure pointer)
with an implicit interface as an actual argument to correspond with
a dummy procedure (pointer), but it's not an error. Change to a
warning, and modify tests accordingly.
Differential Revision: https://reviews.llvm.org/D108932
According to C7109, "A boz-literal-constant shall appear only as a
data-stmt-constant in a DATA statement, or where explicitly allowed in
16.9 as an actual argument of an intrinsic procedure." This change
enforces that constraint for output list items.
I also added a general interface to determine if an expression is a BOZ
literal constant and changed all of the places I could find where it
could be used.
I also added a test.
This change stemmed from the following issue --
https://gitlab-master.nvidia.com/fortran/f18-stage/issues/108
Differential Revision: https://reviews.llvm.org/D106893
Since BOZ literal arguments are typeless, we cannot know how to pass them as
actual arguments to procedures with implicit interfaces. This change avoids
the problem by emitting an error message in such situations.
This change stemmed from the following issue --
https://github.com/flang-compiler/f18-llvm-project/issues/794
Differential Revision: https://reviews.llvm.org/D106831
To ensure that errors are emitted by CheckConformance and
its callers in all situations, it's necessary for the returned result
of that function to distinguish between three possible
outcomes: the arrays are known to conform at compilation time,
the arrays are known to not conform (and a message has been
produced), and an indeterminate result in which is not possible
to determine conformance. So convert CheckConformance's
result into an optional<bool>, and convert its confusing
Boolean flag arguments into a bit-set of named flags too.
Differential Revision: https://reviews.llvm.org/D103654
Fortran permits a reference to a function whose result is a pointer
to be used as a definable variable in any context where a
designator could appear. This patch wrings out remaining bugs
with such usage and adds more testing.
The utility predicate IsProcedurePointer(expr) had a misleading
name which has been corrected to IsProcedurePointerTarget(expr).
Differential Revision: https://reviews.llvm.org/D98555
Analyze the shape of the result of TRANSFER(ptr,array) correctly
when "ptr" is an array of deferred shape. Fixing this bug led to
some refactoring and concentration of common code in TypeAndShape
member functions with code in general shape and character length
analysis, and this led to some regression test failures that have
all been cleaned up.
Differential Revision: https://reviews.llvm.org/D95744
