Ensure that the semantic error "An allocatable or pointer component
reference must be applied to a scalar base" is emitted with a source
code location.
Differential Revision: https://reviews.llvm.org/D135215
When a scalar expression is not expandable -- i.e., it would have to be
evaluated once and saved in a temporary to avoid changing the semantics
of the program if it were to be evaluated more than once -- it affects
some aspects of folding and expression semantics. In cases where
scalar expansion would not cause multiple evaluations due to the shape
of the result having but a single element, however, these "non-expandable"
scalar expressions can be safely allowed.
Differential Revision: https://reviews.llvm.org/D134476
Emit a "Assignment to procedure 'foo' is not allowed" error message
for more cases of 'foo' than just declaraed subprograms, rather than
assuming that those additional cases were named constants.
Differential Revision: https://reviews.llvm.org/D132165
Assignment statements need to check for array shape conformance
errors that are discernable at compilation time.
Differential Revision: https://reviews.llvm.org/D132161
Inaccessible components -- those declared PRIVATE in another module -- should
be allowed to be redeclared in extended types, and should be ignored if
they appear as keywords in structure constructors.
Differential Revision: https://reviews.llvm.org/D131102
F18 disallows function references and coarray references from
appearing in scalar expressions that are to be expanded into
arrays to conform with other operands or actual arguments in
an elemental expression. This is too strong, as pure procedures
can be safely used.
Differential Revision: https://reviews.llvm.org/D131096
This patch fixes:
llvm-project/flang/lib/Semantics/expression.cpp:405:12: error:
moving a local object in a return statement prevents copy elision
[-Werror,-Wpessimizing-move]
A type-param-inquiry of %KIND or %LEN applies to a designator, and
so must also be allowed for a substring. F18 presently (mis)parses
instances of a type-param-inquiry as structure component references
and then fixes them in expression semantics when types are known and
we can distinguish them. But when the base of a type-param-inquiry is
a substring of an array element, as in "charArray(i)(j:k)%len",
parsing fails.
Adjust the grammar to parse these cases, and extend expression semantics
to process the new production.
Differential Revision: https://reviews.llvm.org/D130375
Create a TargetCharacteristics class to centralize the few items of
target specific information that are relevant to semantics. Use the
new class for all target queries, including derived type component layout
modeling.
Future work will initialize this class with target information
provided or forwarded by the drivers, and use it to fold layout-dependent
intrinsic functions like TRANSFER().
Differential Revision: https://reviews.llvm.org/D129018
Updates: Attempts to work around build issues on Windows.
When generic resolution finds its specific procedure in a module,
and that specific procedure is not use-associated into the local scope
(perhaps because it was PRIVATE, perhaps because the generic was
use-associated with ONLY:), we create a new use-association with
a renaming. The name constructed for this renaming needs to be
additionally qualified with the module name of the specific procedure
in order to avoid clashing with another specific of the same name
that may have previously been use-associated in the same way from
a distinct module.
Differential Revision: https://reviews.llvm.org/D127790
The previous semantic analysis does not consider when the last part-ref
is scalar or complex part. Refactor the previous code and bring all the
checks into one place. The check starts from the designator by
extracting the dataref wrapped including the substring and complex part
and recursively check the base objects.
Co-authored-by: Peter Klausler <pklausler@nvidia.com>
Reviewed By: klausler
Differential Revision: https://reviews.llvm.org/D126595
As an extension for REAL literals, we allow an exponent letter which
matches an explicit kind-param. The standard requires the exponent
to be 'E' if a kind-param is present. This patch
- documents this extension in Extensions.md
- enables a portability warning if it is used with -pedantic
The test case for this, kinds05.f90, needs D125804, which makes
test_errors.py test warnings as well, to actually test the warnings.
I include it already now to keep things together, it will do no harm
(I hope ...).
We also add WARNING-directives to the test kinds04.f90 in preparation
for D125804. As the exponent-letter 'Q' does not imply the same kind
on all platforms, the emitted warnings are platform-dependent.
Therefore, the test is duplicated into two variants which are run
conditionally.
Finally, we promote the portability warning for when the exponent letter
is neither 'E' nor matching the kind-param to a standard warning.
Reviewed By: klausler
Differential Revision: https://reviews.llvm.org/D126459
When two or more generic interfaces are available by declaration or
by USE association at different scoping levels, we need to search
the outer generic interfaces as well as the inner ones, but only after
the inner ones have failed to produce a specific procedure that matches
a given set of actual arguments. This means that it is possible for
a specific procedure of a generic interface of an inner scope to override
a conflicting specific procedure of a generic interface of an outer
scope.
Also cope with forward references to derived types when a generic
interface is also in scope.
Fixes LLVM bug https://github.com/llvm/llvm-project/issues/55240 and
LLVM bug https://github.com/llvm/llvm-project/issues/55300.
Differential Revision: https://reviews.llvm.org/D126587
When processing the literal constants of the various kinds of
INTEGER that are too large by 1 (e.g., 2147483648_4) in expression
analysis, emit a portability warning rather than a fatal error if
the literal constant appears as the operand to a unary minus, since
the folded result will be in range. And don't emit any warning if
the negated literal is coming from a module file -- f18 wrote the
module file and the warning would simply be confusing, especially to
the programmer that wrote (-2147483647_4-1) in the first place.
Further, emit portability warnings for the canonical expressions for
infinities and NaN (-1./0., 0./0., & 1./0.), but not when they appear
in a module file, for the same reason. The Fortran language has no
syntax for these special values so we have to emit expressions that
fold to them.
Fixes LLVM bugs https://github.com/llvm/llvm-project/issues/55086 and
https://github.com/llvm/llvm-project/issues/55081.
Differential Revision: https://reviews.llvm.org/D126584
A recent fix beefed up semantics checking to catch the case of a call
to an external assumed-length character function; this check has false
positives in the case of an assumed-length character function that is
a dummy procedure. These do have a length that is passed in extra
compiler-created arguments. This patch refines the check and undoes some
changes to tests.
Differential Revision: https://reviews.llvm.org/D126390
The purity or impurity of a call to a generic interface
depends on the attributes of the specific procedure or specific
binding. Change expression analysis of calls to generic interfaces
to replace the symbol in the parse tree with the specific procedure
or binding; this ensures that later checking for purity in
DO CONCURRENT and other contexts will be accurate.
Remove an "XFAIL" from a test that now passes again with this fix.
Differential Revision: https://reviews.llvm.org/D126150
Semantics was allowing calls to CHARACTER(*) functions, which are odd
things -- they can be declared, and passed around, but can never actually
be called as such. They must be redeclared with an explicit length that
ends up being passed as a hidden argument. So check for these calls
and diagnose them, add tests, and clean up some existing tests that
were in error and now get caught.
Possible TODO for lowering: there were some test cases that used
bad calls to assumed-length CHARACTER*(*) functions and validated
their implementations. I've removed some, and adjusted another,
but the code that somehow implemented these calls may need to be
removed and replaced with an assert about bad semantics.
Differential Revision: https://reviews.llvm.org/D126148
Complex component references (z%RE, z%IM) of complex named constants
should be evaluated at compilation time.
Differential Revision: https://reviews.llvm.org/D125341
When resolving a procedure reference, do not allow a successful
intrinsic procedure probe result to override an existing
symbol.
Differential Revision: https://reviews.llvm.org/D123905
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().
The x%KIND inquiry needs to be supported when 'x' is itself
a complex part reference or a type parameter inquiry.
Differential Revision: https://reviews.llvm.org/D123733
For parameterized derived type component initializers whose
expressions' types depend on parameter values, f18's current
scheme of analyzing the initialization expression once during
name resolution fails. For example,
type :: pdt(k)
integer, kind :: k
real :: component = real(0.0, kind=k)
end type
To handle such cases, it is necessary to re-analyze the parse
trees of these initialization expressions once for each distinct
initialization of the type.
This patch adds code to wipe an expression parse tree of its
typed expressions, and update those of its symbol table pointers
that reference type parameters, and then re-analyze that parse
tree to generate the properly typed component initializers.
Differential Revision: https://reviews.llvm.org/D123728
Fortran allows a generic interface to have he same name as an
intrinsic procedure. If the intrinsic is explicitly marked with
the INTRINSIC attribute, restrictions apply (C848) - the generic
must contain only functions or subroutines, depending on the
intrinsic. Explicit or not, the generic overrides the intrinsic,
but the intrinsic behavior must still be available for calls
whose actual arguments do not match any of the specific procedures.
Semantics was not checking constraint C848, and it didn't allow
an explicit INTRINSIC attribute on a name of a generic interface.
Differential Revision: https://reviews.llvm.org/D123713
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
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
Assignment semantics was coughing up bad errors and crashes for
intrinsic assignments to unlimited polymorphic entities while
looking for any (impossible) user defined ASSIGNMENT(=) generic
or intrinsic type conversion.
Differential Revision: https://reviews.llvm.org/D122440
To make it easier to find things that are not yet implemented, I'm changing the
messages that appear in the compiler's output to all have the string "not yet
implemented:".
These changes apply to files in the front end. I have another set of changes
to files in the lowering code.
Differential Revision: https://reviews.llvm.org/D122355
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
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
Calls to C_F_POINTER() without the optional SHAPE= third argument
were failing to be recognized as proper calls to the intrinsic,
but the failure was not generating any error message. This led to
a crash in lowering, which rightfully expects a typed expression
to be associated with the call.
So (1) catch silent failures to convert CALL statements as internal
errors, as is done for expressions and assignment statements; and
(2) clean up C_F_POINTER intrinsic handling to cope with only two
arguments and to emit an error for a FPTR= argument with no type.
Differential Revision: https://reviews.llvm.org/D119847
Semantic analysis was emitting a bogus error message when a structure
constructor contains a monomorphic value for a (limited) polymorphic
component of a derived type. The type compatibility test was too
strict; this patch relaxes it a little to allow values that could
be assigned or passed to a variable or dummy argument with that type.
Also add some quotes to an error message that was sometimes confusing
without them, and remove a repeated space character from another.
Differential Revision: https://reviews.llvm.org/D119744
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
Previously, when calling a procedure implicitly for which a global scope
procedure symbol with the same name existed, semantics resolved the
procedure name in the call to the global symbol without checking that
the symbol interface was compatible with the implicit interface of the
call.
This could cause expression rewrite and lowering to later badly process
the implicit call assuming a different result type or an explicit
interface. This could lead to lowering crash in case the actual argument
were incompatible with the dummies from the explicit interface.
Emit errors in the following problematic cases:
- If the result type from the symbol did not match the one from the
implicit interface.
- If the symbol requires an explicit interface.
This patch still allows calling an F77 like procedure with different
actual argument types than the one it was defined with because it is
correctly supported in lowering and is a feature in some program
(it is a pointer cast). The two cases that won't be accepted have
little chance to make much sense. Results returning ABIs may differ
depending on the return types, and function that requires explicit
interface usually requires descriptors or specific processing that
is incompatible with implicit interfaces.
Note that this patch is not making a deep analysis, and it will only
catch mistakes if a global symbol and an implicit interface are
involved. Cases where the user provided a conflicting explicit
interface would still require a pass after name resolution to study
conflicts more deeply. But these cases will not crash lowering or
trigger expression rewrite to do weird things.
Differential Revision: https://reviews.llvm.org/D119274
When constructing the representation for a component reference
to an inherited component, expression semantics make the parent
component references explicit in the DataRef; e.g., base%component
becomes base%parent%grandparent%component if component was
inheritance-associated through two levels. But expression semantics
was inserting references to the symbol table entries for the
intermediate types, not the symbols for the parent components in
the extended types. (We didn't notice the distinction until
recently because both symbols have the same name; this only
affects lowering.) Find and use the right symbols.
Differential Revision: https://reviews.llvm.org/D118746
When a scalar-valued function with no distinct RESULT
is being called recursively in its own executable part,
emit a better message about the error. Clean up the
code that resolves function vs. array ambiguities in
expression semantics.
Update to address review comment
Differential Revision: https://reviews.llvm.org/D117577
A bogus error message is appearing for structure constructors containing
values that correspond to unlimited polymorphic allocatable components.
A value of any type can actually be used.
Differential Revision: https://reviews.llvm.org/D117154
A CHECK() in semantics is triggering when analyzing a program
with an undefined derived type pointer because the CHECK is
expecting a new error message to have been issued in a function
but not allowing for the case that a diagnostic could have been
produced earlier. Adjust the predicate.
Differential Revision: https://reviews.llvm.org/D113307
While "null()" is accepted as a data statement constant when it
corresponds to a pointer object, "null(mold=p)" and "null(p)"
are not allowed. The current error messages simply complain
that null is not an array. This patch adds a context-sensitive
message to the effect that a data statement constant followed
by non-empty parentheses must be an array or structure constructor.
(Note that f18 can't simply special-case the name "null" when parsing
data statement constants, since programs are free to repurpose that
name as an array or derived type.)
Differential Revision: https://reviews.llvm.org/D112740
Check that when a procedure pointer is initialised or assigned with an intrinsic
function, or when its interface is being defined by one, that intrinsic function
is unrestricted specific (listed in Table 16.2 of F'2018).
Mark intrinsics LGE, LGT, LLE, and LLT as restricted specific. Getting their
classifications right helps in designing the tests.
Differential Revision: https://reviews.llvm.org/D112381
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
A reference to an allocatable or pointer component must be applied
to a scalar base object. (This is the second part of constraint C919;
the first part is already checked.)
Differential Revision: https://reviews.llvm.org/D112241
Semantics is rejecting valid programs with NULL() actual arguments
to generic interfaces, including user-defined operators. Subclause
16.9.144(para 6) makes clear that NULL() can be a valid actual
argument to a generic interface so long as it does not produce
ambiguity. This patch handles those cases, revises existing
tests, and adjust an error message about NULL() operands to
appear less like a blanket prohibition.
Differential Revision: https://reviews.llvm.org/D111850
Rearrange the contents of __builtin_* module files a little and
make sure that semantics implicitly USEs the module __Fortran_builtins
before processing each source file. This ensures that the special derived
types for TEAM_TYPE, EVENT_TYPE, LOCK_TYPE, &c. exist in the symbol table
where they will be available for use in coarray intrinsic function
processing.
Update IsTeamType() to exploit access to the __Fortran_builtins
module rather than applying ad hoc name tests. Move it and some
other utilities from Semantics/tools.* to Evaluate/tools.* to make
them available to intrinsics processing.
Add/correct the intrinsic table definitions for GET_TEAM, TEAM_NUMBER,
and THIS_IMAGE to exercise the built-in TEAM_TYPE as an argument and
as a result.
Add/correct/extend tests accordingly.
Differential Revision: https://reviews.llvm.org/D110356
A defined assignment subroutine invoked in the context of a WHERE
statement or construct must necessarily be elemental (C1032).
Differential Revision: https://reviews.llvm.org/D109932
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
The index of an implied DO loop in a DATA statement or array
constructor is defined by Fortran 2018 to have scope over its
implied DO loop. This definition is unfortunate, because it
requires the implied DO loop's bounds expressions to be in the
scope of the index variable. Consequently, in code like
integer, parameter :: j = 5
real, save :: a(5) = [(j, j=1, j)]
the upper bound of the loop is a reference to the index variable,
not the parameter in the enclosing scope.
This patch limits the scope of the index variable to the "body"
of the implied DO loop as one would naturally expect, with a warning.
I would have preferred to make this a hard error, but most Fortran
compilers treat this case as f18 now does. If the standard
were to be fixed, the warning could be made optional.
Differential Revision: https://reviews.llvm.org/D108595
Peter Klausler