Correct "is a not a pointer" to "is not a pointer" in an error message.
While here, also unsplit nearby error messages so that their contents
are more searchable.
Fixes https://github.com/llvm/llvm-project/issues/150864.
When the actual argument associated with an explicitly CONTIGUOUS
pointer dummy argument is itself a pointer, it must also be contiguous.
(A non-pointer actual argument can associate with a CONTIGUOUS pointer
dummy argument if it's INTENT(IN), and in that case it's still just a
warning if we can't prove at compilation time that the actual is
contiguous.)
Fixes https://github.com/llvm/llvm-project/issues/138899.
The standard says in [8.5.20 VOLATILE attribute]:
If an object has the VOLATILE attribute, then all of its sub-objects
also have the VOLATILE attribute.
This code takes this into account and uses the volatility of the base of
the designator instead of that of the component. In fact, fields in a
structure are not allowed to have the volatile attribute. So given the
code, `A%B => t`, symbol `B` could never directly have the volatile
attribute, and the volatility of `A` indicates the volatility of `B`.
This PR should address [the
comments](https://github.com/llvm/llvm-project/pull/132486#issuecomment-2851313119)
on this PR #132486
Refine handling of NULL(...) in semantics to properly distinguish
NULL(), NULL(objectPointer), NULL(procPointer), and NULL(allocatable)
from each other in relevant contexts.
Add IsNullAllocatable() and IsNullPointerOrAllocatable() utility
functions. IsNullAllocatable() is true only for NULL(allocatable); it is
false for a bare NULL(), which can be detected independently with
IsBareNullPointer().
IsNullPointer() now returns false for NULL(allocatable).
ALLOCATED(NULL(allocatable)) now works, and folds to .FALSE.
These utilities were modified to accept const pointer arguments rather
than const references; I usually prefer this style when the result
should clearly be false for a null argument (in the C sense), and it
helped me find all of their use sites in the code.
F'2023 C1017 permits the assignment of an unlimited polymorphic data
target to a monomorphic LHS pointer when the LHS pointer has a sequence
derived type (BIND(C) or SEQUENCE attribute). We allowed for this in
pointer assignments that don't have a function reference as their RHS.
Extend this support to function references, and also ensure that rank
compatibility is still checked.
(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().
As specified in the docs,
1) raw_string_ostream is always unbuffered and
2) the underlying buffer may be used directly
( 65b13610a5226b84889b923bae884ba395ad084d for further reference )
Avoid unneeded calls to raw_string_ostream::str(), to avoid excess indirection.
When the result of a function never appears in a variable definition
context, emit a warning.
If the function has multiple result variables due to alternate ENTRY
statements, any definition will suffice.
The implementation of this check is tied to the general variable
definability checking utility in semantics. Every variable definition
context uses it to ensure that no undefinable variable is being defined.
A set of defined variables is maintained in the SemanticsContext and,
when the warning is enabled and no fatal error has been reported, the
scope tree is traversed and all the function subprograms' results are
tested for membership in that set.
f18 current emits an error when an assignment is made to an array
section with a vector subscript, and the array is finalized with a
non-elemental final subroutine. Some other compilers emit this error
because (I think) they want variables to only be finalized in place, not
by a subroutine call involving copy-in & copy-out of the finalized
elements.
Since many other Fortran compilers can handle this case, and there's
nothing in the standards to preclude it, let's downgrade this error
message to a portability warning.
This patch got complicated because the API for the WhyNotDefinable()
utility routine was such that it would return a message only in error
cases, and there was no provision for returning non-fatal messages. It
now returns either nothing, a fatal message, or a non-fatal warning
message, and all of its call sites have been modified to cope.
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>`.
…Warn()
Many warning messages were being emitted unconditionally. Ensure that
all warnings are conditional on a true result from a call to
common::LanguageFeatureControl::ShouldWarn() so that it is easy for a
driver to disable them all, or, in the future, to provide per-warning
control over them.
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.
…uous function.
Fix from [thtsikas](https://github.com/thtsikas) based on a discussion
in
[slack](https://flang-compiler.slack.com/archives/C5C58TT32/p1711124374836079).
Example:
```
Program test
Integer, Pointer, Contiguous :: cont(:)
Interface
Function f()
Integer, Pointer :: f(:)
End Function
End Interface
cont => f()
Print *, cont(3)
End Program
Function f()
Integer, Pointer :: f(:)
Allocate (f(4),Source=[1,1,42,1])
! f => f(4:1:-1) !! not contiguous, runtime error
End Function f
```
Understanding is that the standard intended to allow this pattern. The
restriction 10.2.2.3 p6 Data pointer assignment "If the pointer object
has the CONTIGUOUS attribute, the pointer target shall be contiguous."
is not associated with a numbered constraint. If there is a mechanism
for injecting runtime checks, this would be a place to do it. Absent
that, a warning is the best we can do.
No other compiler treats contigPtr => func() as an error when func() is
not CONTIGUOUS, so a warning would probably be better for consistency.
https://godbolt.org/z/5cM6roeEE
…istinguishing characteristic
We note whether a procedure's interface is explicit or implicit as an
attribute of its characteristics, so that other semantics can be checked
appropriately, but this internal attribute should not be used as a
distinguishing characteristic in itself.
Fixes https://github.com/llvm/llvm-project/issues/81876.
…arrays
When comparing dummy array extents, cope with references to symbols
better (including references to other dummy arguments), and emit
warnings in dubious cases that are not equivalent but not provably
incompatible.
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.
…e pointer
The procedure characterization package correctly characterizes the
result of a reference to a function that returns a procedure pointer. In
the event of a result that is a pointer to a function that itself is a
procedure pointer, the code in pointer assignment semantics checking was
mistakenly using that result's procedure characteristics as the
characteristics of the original function reference. This is just wrong;
delete it.
Implements compatibility checking for initializers in procedure pointer
declarations. This work exposed some inconsistency in how ELEMENTAL
interfaces were handled and checked, from both unrestricted intrinsic
functions and others, and some refinements needed for function result
compatbility checking; these have also been ironed out. Some new
warnings are now emitted, and this affected a dozen or so tests.
Differential Revision: https://reviews.llvm.org/D159026
Establish a set of optional usage warnings, and enable some
only in "-pedantic" mode that, in our subjective experience
with application codes, seem to issue frequently without
indicating usage that really needs to be corrected. By default,
with this patch the compiler should appear to be somewhat less
persnickety but not less informative.
Differential Revision: https://reviews.llvm.org/D150710
Don't check ranks when a pointer actual argument is associated with
a pointer assumed-rank dummy argument.
Differential Revision: https://reviews.llvm.org/D147052
Consolidate aspects of pointer assignment & structure constructor pointer component
checking from Semantics/assignment.cpp and /expression.cpp into /pointer-assignment.cpp,
and add a warning about data targets that are not definable objects
but not hard errors. Specifically, a structure component pointer component data
target is not allowed to be a USE-associated object in a pure context by a numbered
constraint, but the right-hand side data target of a pointer assignment statement
has no such constraint, and that's the new warning.
Differential Revision: https://reviews.llvm.org/D146581
When character lengths are known at compilation time, report an error
when a data target with a known length does not match the explicit length
of a pointer that is being associated with it; see 10.2.2.3 paragraph 5.
Differential Revision: https://reviews.llvm.org/D142755
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
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
When a procedure pointer component has an interface that is a forward
reference to a procedure, syntax errors can be emitted if there is
a structure constructor that tries to initialize that component,
since its characteristics are not yet known; however, when the
initializer is a bare NULL(with no mold), those characteristics
don't matter. Make the characterization of the procedure pointer
component take place only when needed.
Differential Revision: https://reviews.llvm.org/D131100
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
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
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().
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
When a pointer assignment with bounds remapping has a function
reference as its right-hand side, don't check for array conformance.
Differential Revision: https://reviews.llvm.org/D119845
The IsPointer check currently fails for host-associated symbols in OpenMP
regions. This causes some failures in semantic checks for pointer association
in an OpenMP region. Fix is to use the ultimate symbol in the call to the
IsPointer function in CheckPointerAssignment function in
lib/Semantics/pointer-assignment.cpp.
Reviewed By: klausler, peixin
Differential Revision: https://reviews.llvm.org/D112876
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
When a function is called in a specification expression, it must be
sufficiently defined, and cannot be a recursive call (10.1.11(5)).
The best fix for this is to change the contract for the procedure
characterization infrastructure to catch and report such errors,
and to guarantee that it does emit errors on failed characterizations.
Some call sites were adjusted to avoid cascades.
Differential Revision: https://reviews.llvm.org/D104330
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
This patch plugs many holes in static initializer semantics, improves error
messages for default initial values and other component properties in
parameterized derived type instantiations, and cleans up several small
issues noticed during development. We now do proper scalar expansion,
folding, and type, rank, and shape conformance checking for component
default initializers in derived types and PDT instantiations.
The initial values of named constants are now guaranteed to have been folded
when installed in the symbol table, and are no longer folded or
scalar-expanded at each use in expression folding. Semantics documentation
was extended with information about the various kinds of initializations
in Fortran and when each of them are processed in the compiler.
Some necessary concomitant changes have bulked this patch out a bit:
* contextual messages attachments, which are now produced for parameterized
derived type instantiations so that the user can figure out which
instance caused a problem with a component, have been added as part
of ContextualMessages, and their implementation was debugged
* several APIs in evaluate::characteristics was changed so that a FoldingContext
is passed as an argument rather than just its intrinsic procedure table;
this affected client call sites in many files
* new tools in Evaluate/check-expression.cpp to determine when an Expr
actually is a single constant value and to validate a non-pointer
variable initializer or object component default value
* shape conformance checking has additional arguments that control
whether scalar expansion is allowed
* several now-unused functions and data members noticed and removed
* several crashes and bogus errors exposed by testing this new code
were fixed
* a -fdebug-stack-trace option to enable LLVM's stack tracing on
a crash, which might be useful in the future
TL;DR: Initialization processing does more and takes place at the right
times for all of the various kinds of things that can be initialized.
Differential Review: https://reviews.llvm.org/D92783
Calling "ASSOCATED(NULL()) was causing an internal check of the compiler to
fail.
I fixed this by changing the entry for "ASSOCIATED" in the intrinsics table to
accept "AnyPointer" which contains a new "KindCode" of "pointerType". I also
changed the function "FromActual()" to return a typeless intrinsic when called
on a pointer, which duplicates its behavior for BOZ literals. This required
changing the analysis of procedure arguments. While testing processing for
procedure arguments, I found another bad call to `CHECK()` which I fixed.
I made several other changes:
-- I implemented constant folding for ASSOCIATED().
-- I fixed handling of NULL() in relational operations.
-- I implemented semantic analysis for ASSOCIATED().
-- I noticed that the semantics for ASSOCIATED() are similar to those for
pointer assignment. So I extracted the code that pointer assignment uses
for procedure pointer compatibility to a place where it could be used by
the semantic analysis for ASSOCIATED().
-- I couldn't figure out how to make the general semantic analysis for
procedure arguments work with ASSOCIATED()'s second argument, which can
be either a pointer or a target. So I stopped using normal semantic
analysis for arguments for ASSOCIATED().
-- I added tests for all of this.
Differential Revision: https://reviews.llvm.org/D88313
Represent FINAL subroutines in the symbol table entries of
derived types. Enforce constraints. Update tests that have
inadvertent violations or modified messages. Added a test.
The specific procedure distinguishability checking code for generics
was used to enforce distinguishability of FINAL procedures.
(Also cleaned up some confusion and redundancy noticed in the
type compatibility infrastructure while digging into that area.)
Differential revision: https://reviews.llvm.org/D88613
Rolls up small changes across the frontend to prepare for the large
forthcoming patch (part 4/4) that completes DATA statement processing
via conversion to initializers.
Reviewed By: PeteSteinfeld
Differential Revision: https://reviews.llvm.org/D82137
