(This is a big patch, but it's nearly an NFC. No test results have
changed and all Fortran tests in the LLVM test suites work as expected.)
Allow a parser::Message for a warning to be marked with the
common::LanguageFeature or common::UsageWarning that controls it. This
will allow a later patch to add hooks whereby a driver will be able to
decorate warning messages with the names of its options that enable each
particular warning, and to add hooks whereby a driver can map those
enumerators by name to command-line options that enable/disable the
language feature and enable/disable the messages.
The default settings in the constructor for LanguageFeatureControl were
moved from its header file into its C++ source file.
Hooks for a driver to use to map the name of a feature or warning to its
enumerator were also added.
To simplify the tagging of warnings with their corresponding language
feature or usage warning, to ensure that they are properly controlled by
ShouldWarn(), and to ensure that warnings never issue at code sites in
module files, two new Warn() member function templates were added to
SemanticsContext and other contextual frameworks. Warn() can't be used
before source locations can be mapped to scopes, but the bulk of
existing code blocks testing ShouldWarn() and FindModuleFile() before
calling Say() were convertible into calls to Warn(). The ones that were
not convertible were extended with explicit calls to
Message::set_languageFeature() and set_usageWarning().
Specification expressions may contain references to dummy arguments,
host objects, module variables, and variables in COMMON blocks, since
they will have values on entry to the scope. A local variable with a
initializer and the SAVE attribute (which will always be implied by an
explicit initialization) will also always work, and is accepted by at
least one other compiler, so accept it with a warning.
When a local character variable with non-constant length has an
initializer, it's an error in a couple of ways (SAVE variable with
unknown size, static initializer that isn't constant due to conversion
to an unknown length). The error that f18 reports is the latter, but the
message contains a formatted representation of the initialization
expression that exposes a non-Fortran %SET_LENGTH() operation. Print the
original expression in the message instead.
Transformational functions from the intrinsic module ISO_C_BINDING are
allowed in specification expressions, so tweak some general checks that
would otherwise trigger error messages about inadmissible targets, dummy
procedures in specification expressions, and pure procedures with impure
dummy procedures.
SIZEOF and C_SIZEOF were broken for assumed-ranks because
`TypeAndShape::MeasureSizeInBytes` behaved as a scalar because the
`TypeAndShape::shape_` member was the same for scalar and assumed-ranks.
The easy fix would have been to add special handling in
`MeasureSizeInBytes` for assumed-ranks using the TypeAndShape
attributes, but I think this solution would leave `TypeAndShape::shape_`
manipulation fragile to future developers. Hence, I went for the
solution that turn shape_ into a `std::optional<Shape>`.
No specification expression in the declaration of the result variable of
an elemental function may depend on the value of a dummy argument. This
ensures that all of the results have the same type when the elemental
function is applied to the elements of an array.
Lower select rank according to [assumed-rank lowering design
doc](https://github.com/llvm/llvm-project/blob/main/flang/docs/AssumedRank.md).
The construct is lowered using fir.box_rank and fir.select_case
operation and, for the non pointer/allocatable case, a
fir.is_assumed_size + conditional branch before the select_case to deal
with the assumed-size case.
The way the CFG logic is generated, apart from the extra conditional
branch for assumed-size, is similar to what is done for SELECT CASE
lowering, hence the sharing of the construct level visitor.
For the CFG parts. The main difference is that we need to keep track of
the selector to cook it and map it inside the cases (hence the new
members of the ConstructContext).
The only TODOs left are to deal with the RANK(*) case for polymorphic
entities and PDTs. I will do the polymorphic case in a distinct patch,
this patch has enough content.
Fortran::evaluate::IsSimplyContiguous change is needed to avoid generating
copy-in/copy-out runtime calls when passing the RANK(*) associating
entity to some implicit interface.
When the characteristics of a procedure depend on a procedure that
hasn't yet been defined, the compiler currently emits an unconditional
error message. This includes the case of a procedure whose
characteristics depend, perhaps indirectly, on itself. However, in the
case where the characteristics of a procedure are needed to resolve a
generic, we should not emit an error for a hitherto undefined procedure
-- either the call will resolve to another specific procedure, in which
case the error is spurious, or it won't, and then an error will issue
anyway.
Fixes https://github.com/llvm/llvm-project/issues/88677.
Address TODOs in the intrinsic module ISO_FORTRAN_ENV, and extend the
implementation of NUMERIC_STORAGE_SIZE so that the calculation of its
value is deferred until it is needed so that the effects of
-fdefault-integer-8 or -fdefault-real-8 are reflected. Emit a warning
when NUMERIC_STORAGE_SIZE is used from the module file and the default
integer and real sizes do not match.
Fixes https://github.com/llvm/llvm-project/issues/87476.
Detect attempts to use non-constant targets, including internal
procedures, as initializers for procedure pointers, including components
of structure components being used as initializers.
Before emitting a warning message, code should check that the usage in
question should be diagnosed by calling ShouldWarn(). A fair number of
sites in the code do not, and can emit portability warnings
unconditionally, which can confuse a user that hasn't asked for them
(-pedantic) and isn't terribly concerned about portability *to* other
compilers.
Add calls to ShouldWarn() or IsEnabled() around messages that need them,
and add -pedantic to tests that now require it to test their portability
messages, and add more expected message lines to those tests when
-pedantic causes other diagnostics to fire.
Pure intrinsic functions are acceptable in constant expressions so long
as their arguments are constant expressions. Allow them to appear in
subscripts in DATA statement variables.
Fixes https://github.com/llvm/llvm-project/issues/65046.
A section of a parameter array may be non-contiguous,
so the current !IsVariable(expr) check is too optimistic
to claim contiguity.
This patch fixes issues with incorrect hlfir.designate op generated
during lowering: the lowering queries IsContiguous to decide whether
to use fir.box<fir.array> or plain fir.ref<fir.array> to represent
the designator result.
Reviewed By: klausler
Differential Revision: https://reviews.llvm.org/D156494
Make __builtin_c_loc() into an intrinsic function and verify the
special semantic requirements on its actual arguments.
Differential Revision: https://reviews.llvm.org/D149988
TYPE(*) arguments fell through in IS_CONTIGUOUS folding
because they are not Expr<SomeType>. Expose entry point for
symbols in IsContiguous and use that.
The added test revealed that IS_CONTIGUOUS was folded to
false for assumed rank arguments. Fix this: the contiguity of
assumed rank without the CONTIGUOUS argument can only be
verified at runtime.
Differential Revision: https://reviews.llvm.org/D148128
Currently, the selector of a construct entity (e.g., ASSOCIATE(x=>a(1:20)))
is inheriting the CONTIGUOUS attribute from its associated variable
even if it has subscripts that make it noncontiguous (a(1:20:2)).
Add construct entities to the dynamic contiguity predicate instead.
Differential Revision: https://reviews.llvm.org/D145114
It's basically impossible to write a switch statement with a case
for every enumerator in an enum class if the cases each have a
return statement and get it to compile without warnings for all
of our build compilers & versions. Rewrite as a sequence of
if statements.
This patch fixes:
flang/lib/Evaluate/check-expression.cpp:509:3: error: default label
in switch which covers all enumeration values
[-Werror,-Wcovered-switch-default]
When a descriptor inquiry or inquiry function's result is
not constant and is known to be impossible to correctly determine
at runtime, raise an error. For example, LEN(X) when X is
a local allocatable variable with deferred length.
Differential Revision: https://reviews.llvm.org/D142759
Implement the visit of component refs in DesignatorBuilder.
The ArrayRef code has to be updated a bit to cope with the
case where the base is an array and the component is also an
array.
Improve the result type of array sections designators (only return
a fir.box if the array section is not contiguous/has dynamic extent).
This required exposing IsContiguous entry point for different
front-end designator nodes (the implementation already existed,
but was internal to check-expression.cpp).
Differential Revision: https://reviews.llvm.org/D141470
Check most of the requiremens of constraint C1577 for statement functions.
The restrictions that prevent recursion are hard errors; the others seem
to be benign legacies and are caught as portability warnings.
Differential Revision: https://reviews.llvm.org/D139136
Some intrinsic functions can handle NULL() as an actual argument; most
can't. Distinguish the two with a new ArgFlag facility in the intrinsic
procedure table. Also transform some confusing Optionality codes that
were standing in for flags into ArgFlags. Last, return false for a NULL()
pointer from the utility IsActuallyConstant(), ensuring that it can
still deal with a nested NULL() for components in structure constructors.
Differential Revision: https://reviews.llvm.org/D136893
Don't return a hard .FALSE. when folding IS_CONTIGUOUS() unless the
subscript triplets are discontiguous and array section is nonempty,
or if the array section is nonempty and there is a vector subscript.
Differential Revision: https://reviews.llvm.org/D135334
When a component array of a named constant is extracted as
a constant value, ensure that the lower bounds of the array
are properly acquired from the declaration of the component.
Differential Revision: https://reviews.llvm.org/D134499
At present, IS_CONTIGUOUS() can only either fold to .TRUE. or
remain unknown. The underlying analysis, however, is capable
of returning a tri-state result (true, false, or unknown).
Extend and expose it to folding so that IS_CONTIGUOUS() can
fold to .FALSE. as well as to .TRUE. when contiguity is
known.
Differential Revision: https://reviews.llvm.org/D134466
The previous code was rewriting all shape inquires on associate
construct entities to inquires on the associated expression or variable.
This is is incorrect because at the point of inquiry, some statement
between the association and the inquiry may have modified the expression
operands or variable in a way that changes its shapes or bounds.
For instance, in the example below, expression rewrites was previously
replacing `size(x, 1)` by `size(p, 1)` which is invalid if p is a
pointer.
```
associate(x => p + 1)
call call_that_may_modify_p_shape()
print *, size(x, 1)
end associate
```
This change restricts rewrites of shape inquiries on associate construct entity
to use the associated expression shape and bounds if and only if the
shape/bounds are compile time constant. Otherwise, this may be invalid.
Differential Revision: https://reviews.llvm.org/D133857
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
F18 preserves lower bounds of explicit-shape named constant arrays, but
failed to also do so for implicit-shape named constants. Fix.
Differential Revision: https://reviews.llvm.org/D127021
Inquiries into the bounds, size, and length of local variables (and function results)
are acceptable specification expressions. A recent change allowed them for dummy
arguments that are not OPTIONAL or INTENT(OUT), but didn't address other object
entities.
Differential Revision: https://reviews.llvm.org/D125343
The rules in the Fortran standard for specification expressions
are full of special cases and exceptions, and semantics didn't get
them exactly right. It is valid to refer to an INTENT(OUT) dummy
argument in a specification expression in the context of a
specification inquiry function like SIZE(); it is not valid to
reference an OPTIONAL dummy argument outside of the context of
PRESENT. This patch makes the specification expression checker
a little context-sensitive about whether it's examining an actual
argument of a specification inquiry intrinsic function or not.
Differential Revision: https://reviews.llvm.org/D125131
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().
In case a character component PDT length only depends on kind parameters,
fold it while instantiating the PDT. This is especially important if the
component has an initializer because later semantic phases (offset
computation or runtime type info generation) might get confused and
generate offset/type info that will lead to crashes in lowering.
Differential Revision: https://reviews.llvm.org/D122938
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
Similarly to LBOUND in https://reviews.llvm.org/D121488, UBOUND must
return zero for an empty dimension, no matter the specification
expression.
Add a GetUBOUND method to be used in expression rewrite that prevents
folding UBOUND to a bound specification expression if the extent is
not a compile time constant.
Fold the case where the extents is known to be zero (and also deal with
this case in LBOUND since we can and should to comply with constant
expression requirements).
Differential Revision: https://reviews.llvm.org/D122242
LBOUND must return 1 for an empty dimension, no matter what
explicit expression might appear in a declaration or arrive in
a descriptor.
Differential Revision: https://reviews.llvm.org/D121488
Using recently established message severity codes, upgrade
non-fatal messages to usage and portability warnings as
appropriate.
Differential Revision: https://reviews.llvm.org/D121246
When a structure constructor does not initialize an allocatable component,
ensure that the typed expression representation contains an explicit
NULL() for the component. Expression semantics already copies default
initialized expressions for nonallocatable components into structure
constructors. This change is expected to simplify lowering.
Differential Revision: https://reviews.llvm.org/D121162
The predicate IsInitialDataTarget() was failing to return a correct true
result in the case of a reference to the intrinsic function NULL() with a
MOLD= argument. Fix, and improve tests for "NULL()" elsewhere in semantics,
checking for an attribute set by intrinsics.cpp rather than the actual name.
Differential Revision: https://reviews.llvm.org/D119452
When a scope's symbol has characteriztics whose specification
expressions depend on other non-constant symbols in the same scope,
f18 rightfully emits an error. However, in the case of usage in
specification expressions involving host association, the program is not
invalid. This can arise, for example, in the case of an internal
function whose result's attributes use host-associated variables.
Differential Revision: https://reviews.llvm.org/D119565
We already accept assignments of INTEGER to LOGICAL (& vice versa)
as an extension, but not initialization. Extend initialization
to cover those cases.
(Also fix misspelling in nearby comment as suggested by code reviewer.)
Decouple an inadvertent dependence cycle by moving two
one-line function definitions into a header file.
Differential Revision: https://reviews.llvm.org/D117159
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
The current code was relying on the fact that allocatables are deferred
shape and that isAssumedShape() should therefore return true for them.
This is not true, because the current parsing/semantic analysis always
builds a semantics::ArraySpec for `x(:)` that returns true to both
isDeferredShape()/isAssumedShape(), whether x is allocatable/pointer or
not.
It proved tricky to change this behavior, so this is a simple fix for
IsSymplyContiguous where it currently matters, but we most likely want
to investigate more and fix the isDeferredShape()/isAssumedShape() in
a second time.
Differential Revision: https://reviews.llvm.org/D114599
Previous code was returning true for `x(:)` where x is a pointer without
the contiguous attribute.
In case the array ref is a whole array section, check the base for contiguity
to solve the issue.
Differential Revision: https://reviews.llvm.org/D114084
When an array's shape involves references to symbols that are not
invariant in a scope -- the classic example being a dummy array
with an explicit shape involving other dummy arguments -- the
compiler was creating shape expressions that referenced those
symbols. This might be valid if those symbols are somehow
captured and copied at each entry point to a subprogram, and
the copies referenced in the shapes instead, but that's not
the case.
This patch introduces a new expression predicate IsScopeInvariantExpr(),
which defines a class of expressions that contains constant expressions
(in the sense that the standard uses that term) as well as references
to items that may be safely accessed in a context-free way throughout
their scopes. This includes dummy arguments that are INTENT(IN)
and not VALUE, descriptor inquiries into descriptors that cannot
change, and bare LEN type parameters within the definitions of
derived types. The new predicate is then used in shape analysis
to winnow out results that would have otherwise been contextual.
Differential Revision: https://reviews.llvm.org/D113309
The Fortran 2018 standard defines the concept of simple contiguity
in subclause 9.5.4 as a characteristic of arrays. So that scalars
may also be used in contexts where simply contiguous arrays are
allowed, f18 treats them as single-element arrays that are trivially
contiguous. This patch documents this semantic extension and
also adds comments to the predicate that implements the concept.
Differential Revision: https://reviews.llvm.org/D111679
