The code below causes flang to crash with an exception.
After fixing the crash flang with an internal error "no symbol found for 'bar'"
This change fixes all the issues.
program name
implicit none
integer, parameter :: bar = 1
integer foo(bar) /bar*2/
end program name
Reviewed By: kiranchandramohan, klausler
Differential Revision: https://reviews.llvm.org/D124914
Name resolution fails with a bogus "is not a variable" error message
when a host-associated object appears in a NAMELIST group. The root
cause is that ConvertToObjectEntity() returns false for host-associated
objects. Fix that, and also apply a similar fix to ConvertToProcEntity()
nearby.
Differential Revision: https://reviews.llvm.org/D124541
At the top level of program units in a source file, two subprograms
are allowed to have the same name if at least one of them has a
distinct interoperable binding name. F18's symbol table requires
(most) symbols in a scope to have distinct names, though. Solve
by using compiler-created names for the symbols of global scope
subprograms that have interoperable binding names.
Differential Revision: https://reviews.llvm.org/D124295
A recent change that corrected the name resolution of a generic interface
when the same name was visible in scope incorrectly prevented a local
generic from shadowing an outer name that is not a generic, subprogram,
or derived type -- e.g., a simple variable -- leading to an inappropriate
error message.
Differential Revision: https://reviews.llvm.org/D124276
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
A POINTER attribute statement is allowed to add the POINTER attribute
to a procedure entity that has already been declared, e.g. with an
INTERFACE block.
Differential Revision: https://reviews.llvm.org/D123732
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
Items in NAMELIST groups might be host-associated implicitly-typed
variables, but name resolution can't know that when the NAMELIST
appears in a specification part and the host's execution part has
not yet been analyzed. So defer NAMELIST group item name resolution
to the end of the execution part. This is safe because nothing
else in name resolution depends on whether a variable is in a
NAMELIST group or not.
Differential Revision: https://reviews.llvm.org/D123723
Construct entities from ASSOCIATE, SELECT TYPE, and SELECT RANK
are modifiable if the are associated with modifiable variables
without vector subscripts. Update WhyNotModifiable() to accept
construct entities that are appropriate.
A need for more general error reporting from one overload of
WhyNotModifiable() caused its result type to change to
std::optional<parser::Message> instead of ::MessageFixedText,
and this change had some consequences that rippled through
call sites.
Some test results that didn't allow for modifiable construct
entities needed to be updated.
Differential Revision: https://reviews.llvm.org/D123722
It is possible for generic interfaces of equivalent (but not necessarily
identical -- operator(.eq.) is equivalent to operator(==)) names to
be declared in a host scope and a nested scope, and the nested declaration
should function as an extension of the host's.
Differential Revision: https://reviews.llvm.org/D123719
A generic interface (however spelled) can have the same name as
an intrinsic procedure in the same scope. When an explicit INTRINSIC
attribute statement appears in a nested scope, semantics was
unconditionally declaring a new symbol that hid the generic entirely.
Catch this case and create instead a host association symbol for
the generic that can then be decorated with the INTRINSIC attribute.
Differential Revision: https://reviews.llvm.org/D123718
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
When a type specification appears in the prefix of a FUNCTION statement,
defer its processing as late as possible so that any symbols in the
tpe specification can be resolved in the function's scope to local
declarations, including use-associated symbols. f18 was already doing
this deferral in a limited form for derived types, and this patch
makes it work for intrinsic type parameter values as well.
In short, "real(kind(x)) function foo(x)" now works as it should.
"As late as possible" means the end of the specification part, or
the first appearance of the function result name in the specification
part.
Differential Revision: https://reviews.llvm.org/D123705
Fortran admits a few ways to have multiple symbols with the
same name in the same scope. Two of them involve generic
interfaces (from INTERFACE or GENERIC, the syntax doesn't matter);
these are allowed to inhabit a scope with either a derived type or
a subprogram that is also a specific procedure of the generic.
(But not both a derived type and a subprogram; they could not
cohabit a scope anyway, generic or not.)
In cases of USE association, f18 needs to be capable of combining
use-associated generic interfaces with other use-associated entities.
Two generics get merged (this case was nearly correct); a generic
and a derived type can merge into a GenericDetails with a shadowed
derivedType(); and a generic can replace or ignore a use-associated
procedure of the same name so long as that procedure is already
one of its specifics.
Further, these modifications to the use-associated generic
interface must be made to a local copy of the symbol. The previous
code was messing directly with the symbol in the module's scope.
The fix is basically a reimplementation of the member function
DoAddUse() in name resolution.
Differential Revision: https://reviews.llvm.org/D123704
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
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
Name resolution was crashing while processing the ENTRY statement
due to a lack of special-case code necessary to handle the indirection
needed when the generic has the same name as the ENTRY.
Differential Revision: https://reviews.llvm.org/D122050
Using recently established message severity codes, upgrade
non-fatal messages to usage and portability warnings as
appropriate.
Differential Revision: https://reviews.llvm.org/D121246
F18 presently has fatal and non-fatal diagnostic messages. We'd like
to make non-fatal warnings stand out better in the output of the compiler.
This will turn out to be a large change that affects many files.
This patch is just the first part. It converts a Boolean isFatal_ data
member of the message classes into a severity code, and defines four
of these codes (Error, Warning, Portability, and a catch-all Other).
Later patches will result from sweeping over the parser and semantics,
changing most non-fatal diagnostic messages into warnings and portability
notes.
Differential Revision: https://reviews.llvm.org/D121228
The symbol table, name resolution, and semantic checks for module
subprograms -- esp. for MODULE FUNCTION and MODULE SUBROUTINE, but
also MODULE PROCEDURE -- essentially assumed that the subprogram
would be defined in a submodule of the (sub)module containing its
interface. However, it is conforming to instead declare a module
subprogram in the *same* (sub)module as its interface, and we need
to handle that case.
Since this case involves two symbols in the same scope with the same
name, the symbol table details for subprograms have been extended
with a pointer to the original module interface, rather than relying
on searching in scopes.
Differential Revision: https://reviews.llvm.org/D120839
Name resolution was properly probing the table of unrestricted
specific intrinsics to find "abs", but failing to capture the
result type and save it in the created symbol table entry.
Differential Revision: https://reviews.llvm.org/D120749
It is generally an error when a USE-associated name clashes
with a name defined locally, but not in all cases; a generic
interface can be both USE-associated and locally defined.
This works, but not when there is also a local subprogram
with the same name, which is valid when that subprogram is
a specific of the local generic. A bogus error issues at
the point of the USE because name resolution will have already
defined a symbol for the local subprogram.
The solution is to collect the names of local generics when
creating the program tree, and then create their symbols as
well if their names are also local subprograms, prior to any
USE association processing.
Differential Revision: https://reviews.llvm.org/D119566
Fortran allows forward references to derived types, including
function results that are typed in a prefix of a FUNCTION statement.
If a type is defined in the body of the function, a reference to
that type from a prefix on the FUNCTION statement must resolve to
the local symbol, even and especially when that type shadows one
from the host scope.
The solution is to defer the processing of that type until the
end of the function's specification part. But the language doesn't
allow for forward references to other names in the prefix, so defer
the processing of the type only when it is not an intrinsic type.
The data structures in name resolution that track this information
for functions needed to become a stack in order to make this work,
since functions can contain interfaces that are functions.
Differential Revision: https://reviews.llvm.org/D119448
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 a scope uses an explicit IMPORT statement to import a
symbol from the scope's host, it should not emit a bogus error
message later if that symbol is used in a specification construct.
The code that checks for imports being hidden by local declarations
was not allowing for the presence of host association (or USE)
indirection symbols in the local scope. Fix by using GetUltimate()
before checking for the hidden symbol.
Differential Revision: https://reviews.llvm.org/D118747
For "USE, INTRINSIC", search only for intrinsic modules;
for "USE, NON_INTRINSIC", do not recognize intrinsic modules.
Allow modules of both kinds with the same name to be used in
the same source file (but not in the same scoping unit, a
constraint of the standard that is now enforced).
The symbol table's scope tree now has a single instance of
a scope with a new kind, IntrinsicModules, whose children are
the USE'd intrinsic modules (explicit or not). This separate
"top-level" scope is a child of the single global scope and
it allows both intrinsic and non-intrinsic modules of the same
name to exist in the symbol table. Intrinsic modules' scopes'
symbols now have the INTRINSIC attribute set.
The search path directories need to make a distinction between
regular directories and the one(s) that point(s) to intrinsic
modules. I allow for multiple intrinsic module directories in
the second search path, although only one is needed today.
Differential Revision: https://reviews.llvm.org/D118631
ENTRY statement names in module subprograms were not acceptable for
use as a "module procedure" in a generic interface, but should be.
ENTRY statements need to have symbols with place-holding
SubprogramNameDetails created for them in order to be visible in
generic interfaces. Those symbols are created from the "program
tree" data structure. This patch adds ENTRY statement names to the
program tree data structure and uses them to generate SubprogramNameDetails
symbols.
Differential Revision: https://reviews.llvm.org/D117345
Derived types with SEQUENCE must have data components of sequence
types; but this rule is relaxed as common an extension in the case of
pointer components, whose targets' types are not really relevant
to the implementation requirements of sequence types.
Differential Revision: https://reviews.llvm.org/D117158
It's not conforming to specify the SAVE attribute more than
once for a variable, but it also doesn't hurt anything and
isn't fatal in other Fortran compilers. Downgrade the
message to a warning for better portability.
Differential Revision: https://reviews.llvm.org/D117153
Implements part of the legacy "DEC structures" feature from
VMS Fortran. STRUCTUREs are processed as if they were derived
types with SEQUENCE. DATA-like object entity initialization
is supported as well (e.g., INTEGER FOO/666/) since it was used
for default component initialization in structures. Anonymous
components (named %FILL) are also supported.
These features, and UNION/MAP, were already being parsed.
An omission in the collection of structure field names in the
case of nested structures with entity declarations was fixed
in the parser.
Structures are supported in modules, but this is mostly for
testing purposes. The names of fields in structures accessed
via USE association cannot appear with dot notation in client
code (at least not yet). DEC structures antedate Fortran 90,
so their actual use in applications should not involve modules.
This patch does not implement UNION/MAP, since that feature
would impose difficulties later in lowering them to MLIR types.
In the meantime, if they appear, semantics will issue a
"not yet implemented" error message.
Differential Revision: https://reviews.llvm.org/D117151
A quick fix last week to the shared library build caused
the predicate IsCoarray(const Symbol &) to be moved from
Semantics to Evaluate. This patch completes that move in
a way that properly combines the existing IsCoarray() tests
for expressions and other object with the test for a symbol.
Differential Revision: https://reviews.llvm.org/D114806
Fold the legacy intrinsic functions LGE, LGT, LLE, & LLT
by rewriting them into character relational expressions and
then folding those. Also fix folding of comparisons of
character values of distinct lengths: the shorter value must
be padded with blanks. (This fix exposed some bad test cases,
which are also fixed.)
Differential Revision: https://reviews.llvm.org/D111843
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
Validation of the optional generic-spec on an END INTERFACE statement
was missing many possible error cases; reimplement it.
Differential Revision: https://reviews.llvm.org/D109910
It only worked for internal procedures of subprograms,
but must also allow for internal procedures of the
main program. This broke the use of host-associated
implicitly-typed symbols in specification expressions
of internal procedures.
Differential Revision: https://reviews.llvm.org/D109262
Don't create new symbols in FORALL, implied DO, or other
construct scopes when an undeclared name appears; use the
innermost enclosing program unit's scope. This clears up
a pending TODO in name resolution, and also exposes (& fixes)
an unnoticed name resolution problem in a module file test.
Differential Revision: https://reviews.llvm.org/D109095
The combined initializers constructed from DATA statements and explicit
static initialization in declarations needs to include derived type
component default initializations, overriding those default values
without complaint with values from explicit DATA statement or declaration
initializations when they overlap. This also has to work for objects
with storage association due to EQUIVALENCE. When storage association causes
default component initializations to overlap, emit errors if and only
if the values differ (See Fortran 2018 subclause 19.5.3, esp. paragraph
10).
The f18 front-end has a module that analyzes and converts DATA statements
into equivalent static initializers for objects. For storage-associated
objects, compiler-generated objects are created that overlay the entire
association and fill it with a combined initializer. This "data-to-inits"
module already exists, and this patch is essentially extension and
clean-up of its machinery to complete the job.
Also: emit EQUIVALENCE to module files; mark compiler-created symbols
and *don't* emit those to module files; check non-static EQUIVALENCE
sets for conflicting default component initializations, so lowering
doesn't have to check them or emit diagnostics.
Differential Revision: https://reviews.llvm.org/D109022
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
https://reviews.llvm.org/D105464 did not correctly cover the case
where the symbol from the host procedure is use associated. Outside
of the mis-parsed ArrayRef case, flang was also creating a symbol with
HostAssociated details inside the internal procedure (pointing to the
use associated symbol in the host). That is what lowering expects.
This patch ensures the same logic is applied in the mis-parsed array-ref name
resolution (and the pointer target name resolution).
Differential Revision: https://reviews.llvm.org/D107759
Dummy procedures can be defined as subprograms with explicit
interfaces, e.g.
subroutine subr(dummy)
interface
subroutine dummy(x)
real :: x
end subroutine
end interface
! ...
end subroutine
but the symbol table had no means of marking such symbols as dummy
arguments, so predicates like IsDummy(dummy) would fail. Add an
isDummy_ flag to SubprogramNameDetails, analogous to the corresponding
flag in EntityDetails, and set/test it as needed.
Differential Revision: https://reviews.llvm.org/D106697
Use derived type information tables to drive default component
initialization (when needed), component destruction, and calls to
final subroutines. Perform these operations automatically for
ALLOCATE()/DEALLOCATE() APIs for allocatables, automatics, and
pointers. Add APIs for use in lowering to perform these operations
for non-allocatable/automatic non-pointer variables.
Data pointer component initialization supports arbitrary constant
designators, a F'2008 feature, which may be a first for Fortran
implementations.
Differential Revision: https://reviews.llvm.org/D106297
Name resolution is always creating symbols with HostAssocDetails
for host variable names inside internal procedures. This helps lowering
identifying and dealing with such variables inside internal procedures.
However, the case where the variable appears in an ArrayRef mis-parsed
as a FunctionRef goes through a different name resolution path that did
not create such HostAssocDetails when needed. Pointer assignment RHS
are also skipping this path.
Add the logic to create HostAssocDetails for host symbols inisde internal
procedures that appear in mis-parsed ArrayRef or in pointer assignment RHS.
Differential Revision: https://reviews.llvm.org/D105464
A recent change that extended semantic analysis for actual arguments
that associate with procedure dummy arguments exposed some bugs in
regression test suites due to points of confusion in symbol table
handling in situations where a generic interface contains a specific
procedure of the same name. When passing that name as an actual
argument, for example, it's necessary to take this possibility into
account because the symbol for the generic interface shadows the
symbol of the same name for the specific procedure, which is
what needs to be checked. So add a small utility that bypasses
the symbol for a generic interface in this case, and use it
where needed.
Differential Revision: https://reviews.llvm.org/D104929
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
Daniil Dudkin