Commit Graph

211 Commits

Author SHA1 Message Date
Peter Klausler de6e88ef5a [flang] Allow POINTER attribute statement on procedure interfaces
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
2022-04-15 20:20:56 -07:00
Peter Klausler 9e7eef9989 [flang] Handle parameter-dependent types in PDT initializers
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
2022-04-15 16:20:41 -07:00
Peter Klausler 7c71ce97e7 [flang] Defer NAMELIST group item name resolution
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
2022-04-14 17:50:03 -07:00
Peter Klausler 625dedc3fe [flang] Allow modification of construct entities
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
2022-04-14 16:58:08 -07:00
Peter Klausler 95199af4ae [flang] Local generics must not shadow host-associated generics
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
2022-04-14 15:43:59 -07:00
Peter Klausler 8065e48218 [flang] Inner INTRINSIC must not shadow host generic
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
2022-04-14 15:42:44 -07:00
Peter Klausler eb14135e35 [flang] Correct interaction between generics and intrinsics
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
2022-04-14 13:56:04 -07:00
Peter Klausler 6111ddedc8 [flang] Defer all function result type processing
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
2022-04-14 10:25:57 -07:00
Peter Klausler 9b200074b1 [flang] Fix combining cases of USE association & generic interfaces
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
2022-04-14 08:59:52 -07:00
Peter Klausler ef141aec3c [flang] Improve appearance of message attachments
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
2022-04-14 07:34:50 -07:00
Mike Kashkarov d2bcb0a129 [flang] Allow IMPLICIT NONE(EXTERNAL) with GenericDetails
Restrictions of IMPLICIT NONE(EXTERNAL) prohibits usage of c_associated from
iso_c_binding (with explicit interface) without external definiton - relax
associated check.

Reviewed By: klausler

Differential Revision: https://reviews.llvm.org/D120971
2022-04-14 12:45:21 +03:00
Andrzej Warzynski 4ca111d4cb Revert "[flang] Add & use a better visit()"
This reverts commit 2ab9990c9e. It has
caused multiple build failures:
*  https://lab.llvm.org/buildbot/#/builders/177/builds/4346
*  https://lab.llvm.org/buildbot/#/builders/180/builds/3803
*  https://lab.llvm.org/buildbot/#/builders/175/builds/10419
*  https://lab.llvm.org/buildbot/#/builders/191/builds/4318
*  https://lab.llvm.org/buildbot/#/builders/173/builds/4274
*  https://lab.llvm.org/buildbot/#/builders/181/builds/4297

All these bots failed with a time-out:
```
command timed out: 1200 seconds without output running [b'ninja', b'-j', b'32'], attempting to kill
```
I'm guessing that that's due to template instantiations failing at some
point (https://reviews.llvm.org/D122441 introduced a custom
implementation of std::visit). Everything seems fine when either:
* building on X86 with GCC or Clang (tested with GCC 9.3 and Clang 12)
* building on AArch64 with GCC (tested with GCC 11)
2022-03-28 10:46:47 +00:00
Peter Klausler 2ab9990c9e [flang] Add & use a better 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
2022-03-25 13:15:20 -07:00
Peter Steinfeld df209b8038 [flang] Make not yet implemented messages more consistent
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
2022-03-24 15:19:40 -07:00
Peter Klausler 54d19ba208 [flang] Fix crash: ENTRY with generic interface of the same name
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
2022-03-22 11:10:30 -07:00
Peter Klausler a53967cd55 [flang] Distinguish usage and portability warning messages
Using recently established message severity codes, upgrade
non-fatal messages to usage and portability warnings as
appropriate.

Differential Revision: https://reviews.llvm.org/D121246
2022-03-08 17:24:52 -08:00
Peter Klausler 2895771faf [flang] Add nonfatal message classes
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
2022-03-08 11:40:45 -08:00
Peter Klausler 396865576f [flang] Accommodate module subprograms defined in the same module
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
2022-03-02 13:07:16 -08:00
Peter Klausler 1e082a4a9c [flang] Fix result type of "procedure(abs) :: f"
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
2022-03-02 11:11:40 -08:00
Peter Klausler fc510998f7 [flang] Fix edge case in USE-associated generics
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
2022-02-11 16:55:05 -08:00
Peter Klausler 93b0638eff [flang] Handle "type(foo) function f" when foo is defined in f
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
2022-02-10 10:29:36 -08:00
Jean Perier 47995a0ec9 [flang] catch implicit interface incompatibility with global scope symbol
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
2022-02-09 09:30:32 +01:00
Peter Klausler aee705661f [flang] Silence bogus error on use after IMPORT
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
2022-02-02 11:15:58 -08:00
Peter Klausler 52a1346b78 [flang] Distinguish intrinsic from non-intrinsic modules
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
2022-01-31 13:31:27 -08:00
Peter Klausler bed947f708 [flang] Accept ENTRY names in generic interfaces
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
2022-01-14 15:43:21 -08:00
Peter Klausler dc65c3f2ff [flang] Allow pointers to non-sequence types in sequence types
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
2022-01-14 10:49:49 -08:00
Peter Klausler 0f500d3dae [flang] Downgrade benign error message to a warning
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
2022-01-13 16:27:40 -08:00
Peter Klausler c14cf92b5a [flang] Implement semantics for DEC STRUCTURE/RECORD
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
2022-01-13 13:17:13 -08:00
Peter Klausler 1ee6f7add1 [flang] Rearrange prototype & code placement of IsCoarray()
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
2021-11-30 15:26:34 -08:00
peter klausler 6965a776ee [flang] Fold LGE/LGT/LLE/LLT intrinsic functions
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
2021-10-14 15:24:03 -07:00
peter klausler 52711fb8da [flang] Make builtin types more easily accessible; use them
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
2021-09-29 13:06:01 -07:00
peter klausler 1894250291 [flang] Revamp C1502 checking of END INTERFACE [generic-spec]
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
2021-09-17 08:13:10 -07:00
peter klausler f348f30d6f [flang] Fix GetHostProcedure() for main program
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
2021-09-07 09:15:23 -07:00
peter klausler a4c5d00cd3 [flang] Fix scope in which undeclared symbols are created
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
2021-09-02 14:16:19 -07:00
peter klausler d60a02201d [flang] Include default component initialization in static initializers
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
2021-09-01 09:40:37 -07:00
peter klausler 3265b93363 [flang] Extension: reduced scope for some implied DO loop indices
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
2021-08-24 09:34:18 -07:00
Jean Perier f2f6190960 [flang] Always create HostAssocDetails for host object symbols with UseDetails
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
2021-08-10 12:38:19 +02:00
Chirag Khandelwal 77ebfba68b [Flang][Openmp] Upgrade TASKGROUP construct to 5.0.
In OMP 5.0 specification clause-list with
* task_reduction
* allocate
were allowed on taskgroup construct.

Fix XFAIL - omp-taskloop01.f90.

Reviewed By: kiranchandramohan

Differential Revision: https://reviews.llvm.org/D93373
2021-08-03 10:27:47 +05:30
peter klausler c4a65434d8 [flang] Symbol representation for dummy SubprogramDetails
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
2021-08-02 10:44:27 -07:00
peter klausler a48e41683a [flang] Run-time derived type initialization and destruction
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
2021-07-20 15:24:16 -07:00
Jean Perier c2d4d6a1fd [flang] Create HostAssocDetails symbols when needed for mis-parsed ArrayRef
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
2021-07-07 10:07:19 +02:00
peter klausler 3cc5d4ff8e [flang] Fix generic/specific procedure confusion
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
2021-06-25 11:54:29 -07:00
peter klausler 562bfe1274 [flang] Complain about more cases of calls to insufficiently defined procedures
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
2021-06-16 18:20:59 -07:00
peter klausler e5813a683a [flang] Fix crashes on calls to non-procedures
When a procedure reference is attempted to an entity that just
isn't a procedure, say so.

Differential Revision: https://reviews.llvm.org/D104329
2021-06-16 12:48:54 -07:00
peter klausler 3061334e0d [flang] Don't crash on some bogus expressions
Recover more gracefully from user errors in expressions.

Differential Revision: https://reviews.llvm.org/D104326
2021-06-16 12:26:39 -07:00
Peter Steinfeld 1b241b9b40 [flang] Handle multiple USE statements for the same module
It's possible to have several USE statements for the same module that
have different mixes of rename clauses and ONLY clauses.  The presence
of a rename cause has the effect of hiding a previously associated name,
and the presence of an ONLY clause forces the name to be visible even in
the presence of a rename.

I fixed this by keeping track of the names that appear on rename and ONLY
clauses.  Then, when processing the USE association of a name, I check to see
if it previously appeared in a rename clause and not in a USE clause.  If so, I
remove its USE associated symbol.  Also, when USE associating all of the names
in a module, I do not USE associate names that have appeared in rename clauses.

I also added a test.

Differential Revision: https://reviews.llvm.org/D104130
2021-06-11 12:27:19 -07:00
Peter Steinfeld 2b795ec682 [flang] Check for undefined derived types
It's possible to specify refer to an undefined derived type as the type of a
component of another derived type and then never define the type of the
component.  We were not detecting this situation.  To fix this, I
changed the value of isForwardReferenced_ in the symbol's
DerivedTypeDetails and checked for it when performing other derived type
checks.

I also had to record the fact that error messages were previously
emitted for the same problem in some cases so that I could avoid
duplicate messages.

I also added a test.

Differential Revision: https://reviews.llvm.org/D103714
2021-06-04 14:33:52 -07:00
peter klausler 69a82d7c08 [flang] Fix spurious "already declared" errors for interfaces
When a subroutine or function symbol is defined in an INTERFACE
block, it's okay if a symbol of the same name appears in a
scope between the global scope and the scope of the INTERFACE.

Differential Revision: https://reviews.llvm.org/D103580
2021-06-03 15:30:43 -07:00
peter klausler e712a92b8f [flang] Fix crash on structure constructor as selector
In something like "ASSOCIATE(X=>T(1))", the "T(1)" is parsed
as a Variable because it looks like a function reference or
array reference; if it turns out to be a structure constructor,
which is something we can't know until we're able to attempt
generic interface resolution in semantics, the parse tree needs
to be fixed up by replacing the Variable with an Expr.

The compiler could already do this for putative function references
encapsulated as Exprs, so this patch moves some code around and
adds parser::Selector to the overloads of expression analysis.

Differential Revision: https://reviews.llvm.org/D103572
2021-06-03 14:48:30 -07:00
peter klausler d3495ffa5e [flang] Fix recent regression (proc. dummy arg on ENTRY)
A recent fix for problems with ENTRY statement handling didn't
get the case of a procedure dummy argument on an ENTRY statement
in an executable part right; the code presumed that those dummy
arguments would be objects, not entities that might be objects or
procedures.  Fix.

Differential Revision: https://reviews.llvm.org/D103098
2021-05-25 10:37:22 -07:00
peter klausler e162dc6f28 [flang] Fix symbol table bugs with ENTRY statements
Dummy arguments of ENTRY statements in execution parts were
not being created as objects, nor were they being implicitly
typed.

When the symbol corresponding to an alternate ENTRY point
already exists (by that name) due to having been referenced
in an earlier call, name resolution used to delete the extant
symbol.  This isn't the right thing to do -- the extant
symbol will be pointed to by parser::Name nodes in the parse
tree while no longer being part of any Scope.

Differential Review: https://reviews.llvm.org/D102948
2021-05-21 17:45:37 -07:00
peter klausler cfc12a2120 [flang] Correct the interpretation of BIND(C,NAME='')
An empty NAME= should mean that there is no C binding, not the
binding that would result from BIND(C) without a NAME=.
See 18.10.2p2.

Differential Revision: https://reviews.llvm.org/D100494
2021-04-14 11:33:31 -07:00
peter klausler 5091671c9b [flang] Enforce a limit on recursive PDT instantiations
For pernicious test cases with explicit non-constant actual
type parameter expressions in components, e.g.:

  type :: t(k)
    integer, kind :: k
    type(t(k+1)), pointer :: p
  end type

we should detect the infinite recursion and complain rather
than looping until the stack overflows.

Differential Revision: https://reviews.llvm.org/D100065
2021-04-09 16:38:32 -07:00
Peter Steinfeld a7afc8a514 [flang] Fix CHECK() calls on erroneous procedure declarations
When writing tests for a previous problem, I ran across situations where the
compiler was failing calls to CHECK().  In these situations, the compiler had
inconsistent semantic information because the programs were erroneous.  This
inconsistent information was causing the calls to CHECK().

I fixed this by avoiding the code that ended up making the failed calls to
CHECK() and making sure that we were only avoiding these situations when the
associated symbols were erroneous.

I also added tests that would cause the calls to CHECK() without these changes.

Differential Revision: https://reviews.llvm.org/D99342
2021-03-29 10:12:35 -07:00
Tim Keith 5d3249e9af [flang] Save binding labels as strings
Binding labels start as expressions but they have to evaluate to
constant character of default kind, so they can be represented as an
std::string. Leading and trailing blanks have to be removed, so the
folded expression isn't exactly right anyway.

So all BIND(C) symbols now have a string binding label, either the
default or user-supplied one. This is recorded in the .mod file.

Add WithBindName mix-in for details classes that can have a binding
label so that they are all consistent. Add GetBindName() and
SetBindName() member functions to Symbol.

Add tests that verifies that leading and trailing blanks are ignored
in binding labels and that the default label is folded to lower case.

Differential Revision: https://reviews.llvm.org/D99208
2021-03-24 11:25:23 -07:00
Tim Keith a76d0207d5 Revert "[flang] Save binding labels as strings"
This reverts commit eb4ad0e3e3.

This was causing a crash compiling omp_lib.f90
2021-03-24 09:48:41 -07:00
Tim Keith eb4ad0e3e3 [flang] Save binding labels as strings
Binding labels start as expressions but they have to evaluate to
constant character of default kind, so they can be represented as an
std::string. Leading and trailing blanks have to be removed, so the
folded expression isn't exactly right anyway.

So all BIND(C) symbols now have a string binding label, either the
default or user-supplied one. This is recorded in the .mod file.

Add WithBindName mix-in for details classes that can have a binding
label so that they are all consistent. Add GetBindName() and
SetBindName() member functions to Symbol.

Add tests that verifies that leading and trailing blanks are ignored
in binding labels and that the default label is folded to lower case.

Differential Revision: https://reviews.llvm.org/D99208
2021-03-24 08:52:29 -07:00
Peter Steinfeld e97d92f0bb [flang] Disallow erroneous procedure declarations
When writing tests for a previous problem, I ran across situations where we
were not producing error messages for declarations of specific procedures of
generic interfaces where every other compiler I tested (except nvfotran) did.
I added a check to CheckExtantExternal() and renamed it since it now checks for
erroneous extant symbols generally.

I also removed a call to this function from processing for ENTRY statements,
since it seemed unnecessary and its presence caused bogus error messages.

I also added some tests for erroneous declarations where we were not producing
error messages.

Differential Revision: https://reviews.llvm.org/D99111
2021-03-22 14:52:45 -07:00
Peter Steinfeld 5727df2714 [flang] Specific procedures named the same as the generic and a derived type
If you specify a specific procedure of a generic interface that has the same
name as both the generic interface and a preceding derived type, the compiler
would fail an internal call to CHECK().  I fixed this by testing for this
situation when processing specific procedures.  I also added a test that will
cause the call to CHECK() to fail without this new code.

Differential Revision: https://reviews.llvm.org/D99085
2021-03-22 10:52:50 -07:00
peter klausler 0d8331c06b [flang] Refine symbol sorting
Replace semantics::SymbolSet with alternatives that clarify
whether the set should order its contents by source position
or not.  This matters because positionally-ordered sets must
not be used for Symbols that might be subjected to name
replacement during name resolution, and address-ordered
sets must not be used (without sorting) in circumstances
where the order of their contents affects the output of the
compiler.

All set<> and map<> instances in the compiler that are keyed
by Symbols now have explicit Compare types in their template
instantiations.  Symbol::operator< is no more.

Differential Revision: https://reviews.llvm.org/D98878
2021-03-18 11:18:14 -07:00
peter klausler 46ade6d0ef [flang] Order Symbols by source provenance
In parser::AllCookedSources, implement a map from CharBlocks to
the CookedSource instances that they cover.  This permits a fast
Find() operation based on std::map::equal_range to map a CharBlock
to its enclosing CookedSource instance.

Add a creation order number to each CookedSource.  This allows
AllCookedSources to provide a Precedes(x,y) predicate that is a
true source stream ordering between two CharBlocks -- x is less
than y if it is in an earlier CookedSource, or in the same
CookedSource at an earlier position.

Add a reference to the singleton SemanticsContext to each Scope.

All of this allows operator< to be implemented on Symbols by
means of a true source ordering.  From a Symbol, we get to
its Scope, then to the SemanticsContext, and then use its
AllCookedSources reference to call Precedes().

Differential Revision: https://reviews.llvm.org/D98743
2021-03-16 15:25:15 -07:00
Peter Steinfeld 1c2935a772 [flang] Prohibit MODULE procedures in the global scope
We were allowing procedures with the MODULE prefix to be declared at the global
scope.  This is prohibited by C1547 and was causing an internal check of the
compiler to fail.

I fixed this by adding a check.  I also added a test that would trigger a crash
without this change.

Differential Revision: https://reviews.llvm.org/D97875
2021-03-03 11:50:50 -08:00
Peter Steinfeld 16005fd979 [flang] Detect circularly defined interfaces of procedures
It's possible to define a procedure whose interface depends on a procedure
which has an interface that depends on the original procedure.  Such a circular
definition was causing the compiler to fall into an infinite loop when
resolving the name of the second procedure.  It's also possible to create
circular dependency chains of more than two procedures.

I fixed this by adding the function HasCycle() to the class DeclarationVisitor
and calling it from DeclareProcEntity() to detect procedures with such
circularly defined interfaces.  I marked the associated symbols of such
procedures by calling SetError() on them.  When processing subsequent
procedures, I called HasError() before attempting to analyze their interfaces.
Unfortunately, this did not work.

With help from Tim, we determined that the SymbolSet used to track the
erroneous symbols was instantiated using a "<" operator which was defined using
the location of the name of the procedure.  But the location of the procedure
name was being changed by a call to ReplaceName() between the times that the
calls to SetError() and HasError() were made.  This caused HasError() to
incorrectly report that a symbol was not in the set of erroneous symbols.

I fixed this by changing SymbolSet to be an unordered set that uses the
contents of the name of the symbol as the basis for its hash function.  This
works because the contents of the name of the symbol is preserved by
ReplaceName() even though its location changes.

I also fixed the error message used when reporting recursively defined
dummy procedure arguments by removing extra apostrophes and sorting the
list of symbols.

I also added tests that will crash the compiler without this change.

Note that the "<" operator is used in other contexts, for example, in the map
of characterized procedures, maps of items in equivalence sets, maps of
structure constructor values, ...  All of these situations happen after name
resolution has been completed and all calls to ReplaceName() have already
happened and thus are not subject to the problem I ran into when ReplaceName()
was called when processing procedure entities.

Note also that the implementation of the "<" operator uses the relative
location in the cooked character stream as the basis of its implementation.
This is potentially problematic when symbols from diffent compilation units
(for example symbols originating in .mod files) are put into the same map since
their names will appear in two different source streams which may not be
allocated in the same relative positions in memory.  But I was unable to create
a test that caused a problem.  Using a direct comparison of the content of the
name of the symbol in the "<" operator has problems.  Symbols in enclosing or
parallel scopes can have the same name.  Also using the location of the symbol
in the cooked character stream has the advantage that it preserves the the
order of the symbols in a structure constructor constant, which makes matching
the values with the symbols relatively easy.

This patch supersedes D97749.

Differential Revision: https://reviews.llvm.org/D97774
2021-03-02 15:18:12 -08:00
Peter Steinfeld 95540f9dbf [flang] Detect circularly defined interfaces of procedures
It's possible to define a procedure whose interface depends on a procedure
which has an interface that depends on the original procedure.  Such a circular
definition was causing the compiler to fall into an infinite loop when
resolving the name of the second procedure.  It's also possible to create
circular dependency chains of more than two procedures.

I fixed this by adding the function HasCycle() to the class DeclarationVisitor
and calling it from DeclareProcEntity() to detect procedures with such
circularly defined interfaces.  I marked the associated symbols of such
procedures by calling SetError() on them.  When processing subsequent
procedures, I called HasError() before attempting to analyze their interfaces.
Unfortunately, this did not work.

With help from Tim, we determined that the SymbolSet used to track the
erroneous symbols was instantiated using a "<" operator which was defined using
the location of the name of the procedure.  But the location of the procedure
name was being changed by a call to ReplaceName() between the times that the
calls to SetError() and HasError() were made.  This caused HasError() to
incorrectly report that a symbol was not in the set of erroneous symbols.

I fixed this by changing SymbolSet to be an unordered set that uses the
contents of the name of the symbol as the basis for its hash function.  This
works because the contents of the name of the symbol is preserved by
ReplaceName() even though its location changes.

I also fixed the error message used when reporting recursively defined
dummy procedure arguments by removing extra apostrophes and sorting the
list of symbols.

I also added tests that will crash the compiler without this change.

Note that the "<" operator is used in other contexts, for example, in the map
of characterized procedures, maps of items in equivalence sets, maps of
structure constructor values, ...  All of these situations happen after name
resolution has been completed and all calls to ReplaceName() have already
happened and thus are not subject to the problem I ran into when ReplaceName()
was called when processing procedure entities.

Note also that the implementation of the "<" operator uses the relative
location in the cooked character stream as the basis of its implementation.
This is potentially problematic when symbols from diffent compilation units
(for example symbols originating in .mod files) are put into the same map since
their names will appear in two different source streams which may not be
allocated in the same relative positions in memory.  But I was unable to create
a test that caused a problem.  Using a direct comparison of the content of the
name of the symbol in the "<" operator has problems.  Symbols in enclosing or
parallel scopes can have the same name.  Also using the location of the symbol
in the cooked character stream has the advantage that it preserves the the
order of the symbols in a structure constructor constant, which makes matching
the values with the symbols relatively easy.

This patch supersedes D97749.

Differential Revision: https://reviews.llvm.org/D97774
2021-03-02 10:53:44 -08:00
Andrzej Warzynski 1253009eb2 Revert "[flang] Detect circularly defined interfaces of procedures"
This reverts commit 93c5e6bb49.

This patch updates resolve102.f90 which is now failing in 6 out 8 of our
public buildbots:
  * http://lab.llvm.org:8011/#/builders/21/builds/9625
  * http://lab.llvm.org:8011/#/builders/134/builds/2395
  * http://lab.llvm.org:8011/#/builders/79/builds/6298
  * http://lab.llvm.org:8011/#/builders/66/builds/2084
  * http://lab.llvm.org:8011/#/builders/135/builds/2485
  * http://lab.llvm.org:8011/#/builders/32/builds/3551

Please see the following revisions for more context:
  * https://reviews.llvm.org/D97201
  * https://reviews.llvm.org/D97749
2021-03-02 14:55:41 +00:00
Peter Steinfeld 93c5e6bb49 [flang] Detect circularly defined interfaces of procedures
It's possible to define a procedure whose interface depends on a procedure
which has an interface that depends on the original procedure.  Such a circular
definition was causing the compiler to fall into an infinite loop when
resolving the name of the second procedure.  It's also possible to create
circular dependency chains of more than two procedures.

I fixed this by adding the function HasCycle() to the class DeclarationVisitor
and calling it from DeclareProcEntity() to detect procedures with such
circularly defined interfaces.  I marked the associated symbols of such
procedures by calling SetError() on them.  When processing subsequent
procedures, I called HasError() before attempting to analyze their interfaces.
Unfortunately, this did not work.

With help from Tim, we determined that the SymbolSet used to track the
erroneous symbols was instantiated using a "<" operator which was defined using
the location of the name of the procedure.  But the location of the procedure
name was being changed by a call to ReplaceName() between the times that the
calls to SetError() and HasError() were made.  This caused HasError() to
incorrectly report that a symbol was not in the set of erroneous symbols.

I fixed this by changing SymbolSet to be an unordered set that uses the
contents of the name of the symbol as the basis for its hash function.  This
works because the contents of the name of the symbol is preserved by
ReplaceName() even though its location changes.

I also fixed the error message used when reporting recursively defined dummy
procedure arguments.

I also added tests that will crash the compiler without this change.

Note that the "<" operator is used in other contexts, for example, in the map
of characterized procedures, maps of items in equivalence sets, maps of
structure constructor values, ...  All of these situations happen after name
resolution has been completed and all calls to ReplaceName() have already
happened and thus are not subject to the problem I ran into when ReplaceName()
was called when processing procedure entities.

Note also that the implementation of the "<" operator uses the relative
location in the cooked character stream as the basis of its implementation.
This is potentially problematic when symbols from diffent compilation units
(for example symbols originating in .mod files) are put into the same map since
their names will appear in two different source streams which may not be
allocated in the same relative positions in memory.  But I was unable to create
a test that caused a problem.  Using a direct comparison of the content of the
name of the symbol in the "<" operator has problems.  Symbols in enclosing or
parallel scopes can have the same name.  Also using the location of the symbol
in the cooked character stream has the advantage that it preserves the the
order of the symbols in a structure constructor constant, which makes matching
the values with the symbols relatively easy.

This change supersedes D97201.

Differential Revision: https://reviews.llvm.org/D97749
2021-03-01 19:07:03 -08:00
Andrzej Warzynski 00e6513374 Revert "[flang] Detect circularly defined interfaces of procedures"
This reverts commit 07de0846a5.

The original patch has caused 6 out 8 of Flang's public buildbots to
fail. As I'm not sure what the fix should be, I'm reverting this for
now. Please see https://reviews.llvm.org/D97201 for more context and
discussion.
2021-03-01 10:34:49 +00:00
Peter Steinfeld 07de0846a5 [flang] Detect circularly defined interfaces of procedures
It's possible to define a procedure whose interface depends on a procedure
which has an interface that depends on the original procedure.  Such a circular
definition was causing the compiler to fall into an infinite loop when
resolving the name of the second procedure.  It's also possible to create
circular dependency chains of more than two procedures.

I fixed this by adding the function HasCycle() to the class DeclarationVisitor
and calling it from DeclareProcEntity() to detect procedures with such
circularly defined interfaces.  I marked the associated symbols of such
procedures by calling SetError() on them.  When processing subsequent
procedures, I called HasError() before attempting to analyze their interfaces.
Unfortunately, this did not work.

With help from Tim, we determined that the SymbolSet used to track the
erroneous symbols was instantiated using a "<" operator which was
defined using the name of the procedure.  But the procedure name was
being changed by a call to ReplaceName() between the times that the
calls to SetError() and HasError() were made.  This caused HasError() to
incorrectly report that a symbol was not in the set of erroneous
symbols.  I fixed this by making SymbolSet be an ordered set, which does
not use the "<" operator.

I also added tests that will crash the compiler without this change.
And I fixed the formatting on an error message from a previous update.

Differential Revision: https://reviews.llvm.org/D97201
2021-02-26 14:44:35 -08:00
peter klausler ea2ff54ccc [flang] Extension: forward refs to dummy args under IMPLICIT NONE
Most Fortran compilers accept the following benign extension,
and it appears in some applications:

  SUBROUTINE FOO(A,N)
    IMPLICIT NONE
    REAL A(N) ! N is used before being typed
    INTEGER N
  END

Allow it in f18 only for default integer scalar dummy arguments.

Differential Revesion: https://reviews.llvm.org/D96982
2021-02-18 13:14:34 -08:00
peter klausler b82a8c3f23 [flang] Warn about useless explicit typing of intrinsics
Fortran 2018 explicitly permits an ignored type declaration
for the result of a generic intrinsic function.  See the comment
added to Semantics/expression.cpp for an explanation of why this
is somewhat dangerous and worthy of a warning.

Differential Revision: https://reviews.llvm.org/D96879
2021-02-17 13:13:59 -08:00
peter klausler 452d7ebc09 [flang] Ensure that intrinsic procedures are PURE &/or ELEMENTAL
The intrinsic procedure table properly classify the various
intrinsics, but the PURE and ELEMENTAL attributes that these
classifications imply don't always make it to the utility
predicates that test symbols for them, leading to spurious
error messages in some contexts.  So set those attribute flags
as appropriate in name resolution, using a new function to
isolate the tests.

An alternate solution, in which the predicates would query
the intrinsic procedure table for these attributes on demand,
was something I also tried, so that this information could
come directly from an authoritative source; but it would have
required references to the intrinsic table to be passed along
on too many seemingly unrelated APIs and ended up looking messy.

Several symbol table tests needed to have their expected outputs
augmented with the PURE and ELEMENTAL flags.  Some bogus messages
that were flagged as such in test/Semantics/doconcurrent01.f90 were
removed, since they are now correctly not emitted.

Differential Revision: https://reviews.llvm.org/D96878
2021-02-17 11:31:33 -08:00
peter klausler 47b97d4bfb [flang] Manage per-specification-part state better
Some state in name resolution is stored in the DeclarationVisitor
instance and processed at the end of the specification part.
This state needs to accommodate nested specification parts, namely
the ones that can be nested in a subroutine or function interface
body.

Differential Revision: https://reviews.llvm.org/D96466
2021-02-10 17:23:53 -08:00
peter klausler ebe74d9592 [flang] Support disabled alternative PARAMETER statement
Legacy Fortran implementations support an alternative form of the
PARAMETER statement; it differs syntactically from the standard's
PARAMETER statement by lacking parentheses, and semantically by
using the type and shape of the initialization expression to define
the attributes of the named constant.  (GNU Fortran gets that part
wrong; Intel Fortran and nvfortran have full support.)

This patch disables the old style PARAMETER statement by default, as
it is syntactically ambiguous with conforming assignment statements;
adds a new "-falternative-parameter-statement" option to enable it;
and implements it correctly when enabled.

Fixes https://bugs.llvm.org/show_bug.cgi?id=48774, in which a user
tripped over the syntactic ambiguity.

Differential Revision: https://reviews.llvm.org/D95697
2021-01-29 15:30:06 -08:00
peter klausler 3738447c96 [flang] Address name resolution problems
Don't emit a bogus error message about a bad forward reference
when it's an IMPORT of a USE-associated symbol; don't ignore
intrinsic functions when USE-associating the contents of a
module when the intrinsic has been explicitly USE'd; allow
PUBLIC or PRIVATE accessibility attribute to be specified
for an enumerator before the declaration of the enumerator.

Differential Revision: https://reviews.llvm.org/D95175
2021-01-21 16:15:38 -08:00
Peter Steinfeld bebbe64075 [flang] Fix creation of deferred shape arrays by POINTER statement
It's possible to  declare deferred shape array using the POINTER
statement, for example:

  POINTER :: var(:)

When analyzing POINTER declarations, we were not capturing the array
specification information, if present.  I fixed this by changing the
"Post" function for "parser::PointerDecl" to check to see if the
declaration contained a "DeferredShapeSpecList".  In such cases, I
analyzed the shape and used to information to declare an "ObjectEntity"
that contains the shape information rather than an "UnknownEntity".

I also added a couple of small tests that fail to compile without these
changes.

Differential Revision: https://reviews.llvm.org/D95080
2021-01-20 13:08:11 -08:00
peter klausler ff3b51b054 [flang] Fix ASSOCIATE statement name resolution
F18 Clause 19.4p9 says:

  The associate names of an ASSOCIATE construct have the scope of the
  block.

Clause 11.3.1p1 says the ASSOCIATE statement is not itself in the block:

  R1102 associate-construct is:  associate-stmt block end-associate-stmt

Associate statement associations are currently fully processed from left
to right, incorrectly interposing associating entities earlier in the
list on same-named entities in the host scope.

    1  program p
    2    logical :: a = .false.
    3    real :: b = 9.73
    4    associate (b => a, a => b)
    5      print*, a, b
    6    end associate
    7    print*, a, b
    8  end

Associating names 'a' and 'b' at line 4 in this code are now both
aliased to logical host entity 'a' at line 2.  This happens because the
reference to 'b' in the second association incorrectly resolves 'b' to
the entity in line 4 (already associated to 'a' at line 2), rather than
the 'b' at line 3.  With bridge code to process these associations,
f18 output is:

 F F
 F 9.73

It should be:

 9.73 F
 F 9.73

To fix this, names in right-hand side selector variables/expressions
must all be resolved before any left-hand side entities are resolved.
This is done by maintaining a stack of lists of associations, rather
than a stack of associations.  Each ASSOCIATE statement's list of
assocations is then visited once for right-hand side processing, and
once for left-hand side processing.

Note that other construct associations do not have this problem.
SELECT RANK and SELECT TYPE each have a single assocation, not a list.
Constraint C1113 prohibits the right-hand side of a CHANGE TEAM
association from referencing any left-hand side entity.

Differential Revision: https://reviews.llvm.org/D95010
2021-01-20 11:18:27 -08:00
peter klausler 1bd083b5d6 [flang] Create names to allow access to inaccessible specifics
When a reference to a generic interface occurs in a specification
expression that must be emitted to a module file, we have a problem
when the generic resolves to a function whose name is inaccessible
due to being PRIVATE or due to a conflict with another use of the
same name in the scope.  In these cases, construct a new name for
the specific procedure and emit a renaming USE to the module file.
Also, relax enforcement of PRIVATE when analyzing module files.

Differential Revision: https://reviews.llvm.org/D94815
2021-01-15 16:56:38 -08:00
Tim Keith d6acf3c201 [flang] Fix use-associated procedure in generic
When a use-associated procedure was included in a generic, we weren't
correctly recording that fact. The ultimate symbol was added rather than
the local symbol.

Also, improve the message emitted for the specific procedure by
mentioning the module it came from.

This fixes one of the problems in https://bugs.llvm.org/show_bug.cgi?id=48648.

Differential Revision: https://reviews.llvm.org/D94696
2021-01-14 16:31:52 -08:00
peter klausler 166e5c335c [flang] Do not create HostAssoc symbols in derived type scopes
When needed due to a specification expression in a derived type,
the host association symbols should be created in the surrounding
subprogram's scope instead.

Differential Revision: https://reviews.llvm.org/D94567
2021-01-13 11:01:27 -08:00
peter klausler a50bb84ec0 [flang] Fix classification of shape inquiries in specification exprs
In some contexts, including the motivating case of determining whether
the expressions that define the shape of a variable are "constant expressions"
in the sense of the Fortran standard, expression rewriting via Fold()
is not necessary, and should not be required.  The inquiry intrinsics LBOUND,
UBOUND, and SIZE work correctly now in specification expressions and are
classified correctly as being constant expressions (or not).  Getting this right
led to a fair amount of API clean-up as a consequence, including the
folding of shapes and TypeAndShape objects, and new APIs for shapes
that do not fold for those cases where folding isn't needed.  Further,
the symbol-testing predicate APIs in Evaluate/tools.h now all resolve any
associations of their symbols and work transparently on use-, host-, and
construct-association symbols; the tools used to resolve those associations have
been defined and documented more precisely, and their clients adjusted as needed.

Differential Revision: https://reviews.llvm.org/D94561
2021-01-13 10:05:14 -08:00
Tim Keith f782d5ea86 [flang] Detect call to abstract interface
A subroutine call or function reference to an abstract interface is
not legal.

Differential Revision: https://reviews.llvm.org/D93872
2020-12-28 16:36:34 -08:00
Tim Keith d55627d221 [flang] Fix bugs in .mod file for abstract interface
When an abstract interface is defined, add the ABSTRACT attribute to
subprogram symbols that define the interface body. Make use of that
when writing .mod files to include "abstract" on the interface statement.

Also, fix a problem with the order of symbols in a .mod file. Sometimes
a name is mentioned before the "real" declaration, e.g. in an access
statement. We want the order to be based on the real definitions. In
these cases we replace the symbol name with an identical name with a
different source location. Then by sorting based on the source location
we get symbols in the right order.

Differential Revision: https://reviews.llvm.org/D93572
2020-12-28 08:50:32 -08:00
Tim Keith bf0870d864 [flang] Fix bug in IMPLICIT NONE(EXTERNAL)
We were only checking the restrictions of IMPLICIT NONE(EXTERNAL) when a
procedure name is first encountered. But it can also happen with an
existing symbol, e.g. if an external function's return type is declared
before is it called. This change adds a check in that branch too.

Differential Revision: https://reviews.llvm.org/D93552
2020-12-18 17:43:53 -08:00
Peter Steinfeld 4e90cad6a6 [flang] Handle undeclared names in EQUIVALENCE statements
Names in EQUIVALENCE statements are only allowed to indicate local
objects as per 19.5.1.4, paragraph 2, item (10).  Thus, a name appearing
in an EQUIVALENCE statement with no corresponding declaration in the
same scope is an implicit declaration of the name.  If that scope
contains an IMPLICIT NONE, it's an error.

I implemented this by adding a state variable to ScopeHandler to
indicate if we're resolving the names in an EQUIVALENCE statement and
then checked this state when resolving names.  I also added a test to
the existing tests for EQUIVALENCE statements.

Differential Revision: https://reviews.llvm.org/D93345
2020-12-16 11:04:27 -08:00
Tim Keith 7082de56b7 [flang] Handle multiple names for same operator
Some operators have more than one name, e.g. operator(==), operator(.eq).
That was working correctly in generic definitions but they can also
appear in other contexts: USE statements and access statements, for
example.

This changes FindInScope to always look for each of the names for
a symbol. So an operator may be use-associated under one name but
declared private under another name and it will be the same symbol.
This replaces GenericSpecInfo::FindInScope which was only usable in
some cases.

Add a version of FindInScope() that looks in the current scope to
simplify many of the calls.

Differential Revision: https://reviews.llvm.org/D93344
2020-12-16 07:06:55 -08:00
Tim Keith 3a0352b85c [flang] Fix bug with USE of USE of generic
When merging use associations into a generic, we weren't handling
the case where the name that was use associated was itself a use
association. This is fixed by following that association to its
ultimate symbol (`useUltimate` in `DoAddUse`).

An example of the bug is `m12d` in `resolve17.f90`. `g` is associated
with `gc` in `m12c` which is associated with `gb` in `m12b`. It was that
last association that we weren't correctly following.

Differential Revision: https://reviews.llvm.org/D93343
2020-12-15 16:11:59 -08:00
Peter Steinfeld 9168a0f515 [flang] Fix bogus message on index-names in the presence of associated entities
The semantic analysis of index-names of FORALL statements looks up symbols with
the same name as the index-name.  This is needed to exclude symbols that are
not objects.  But if the symbol found is host-, use-, or construct-associated
with another entity, the check fails.

I fixed this by getting the root symbol of the symbol found and doing the check
on the root symbol.  This required creating a non-const version of
"GetAssociationRoot()".

Differential Revision: https://reviews.llvm.org/D92970
2020-12-10 07:36:41 -08:00
peter klausler 641ede93ef [flang] Improve initializer semantics, esp. for component default values
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
2020-12-07 14:40:41 -08:00
Peter Steinfeld f24c642178 [flang] Fix bogus message on interface procedure argument names
We were keeping the state of parsed equivalence sets in the class
DeclarationVisitor.  A problem happened when  analyzing the the specification
part of a declaration that contained an EQUIVALENCE statement followed by an
interface block.  The same DeclarationVisitor object that was created for the
outer declaration was being used to analyze the specification part
of a procedure body in the interface block.  When analyzing the specification
part of the procedure in the interface block, the names in the outer
declaration's EQUIVALENCE statement were erroneously compared with the names in
the arguments of the interface procedure.  This resulted in a bogus error
message.

I fixed this by not checking equivalence sets when we're in an interface
block.  I also added a test that will produce an error message without
this change.

Differential Revision: https://reviews.llvm.org/D92501
2020-12-03 12:08:55 -08:00
Tim Keith 86f59de13b [flang] Fix bugs related to merging generics during USE
When the same generic name is use-associated from two modules, the
generics are merged into a single one in the current scope. This change
fixes some bugs in that process.

When a generic is merged, it can have two specific procedures with the
same name as the generic (c.f. module m7c in modfile07.f90). We were
disallowing that by checking for duplicate names in the generic rather
than duplicate symbols. Changing `namesSeen` to `symbolsSeen` in
`ResolveSpecificsInGeneric` fixes that.

We weren't including each USE of those generics in the .mod file so in
some cases they were incorrect. Extend GenericDetails to specify all
use-associated symbols that are merged into the generic. This is used to
write out .mod files correctly.

The distinguishability check for specific procedures of a generic
sometimes have to refer to procedures from a use-associated generic in
error messages. In that case we don't have the source location of the
procedure so adapt the message to say where is was use-associated from.
This requires passing the scope through the checks to make that
determination.

Differential Revision: https://reviews.llvm.org/D92492
2020-12-02 15:13:50 -08:00
Tim Keith 1f525ece4a [flang][NFC] Add GetTopLevelUnitContaining functions
`GetTopLevelUnitContaining` returns the Scope nested in the global scope
that contains the given Scope or Symbol.

Use "Get" rather than "Find" in the name because "Find" implies it might
not be found, which can't happen. Following that logic, rename
`FindProgramUnitContaining` to `GetProgramUnitContaining` and have it
also return a reference rather that a pointer.

Note that the use of "ProgramUnit" is slightly confusing. In the Fortran
standard, "program-unit" refers to what is called a "TopLevelUnit" here.
What we are calling a "ProgramUnit" (here and in `ProgramTree`) includes
internal subprograms while "TopLevelUnit" does not.

Differential Revision: https://reviews.llvm.org/D92491
2020-12-02 10:28:49 -08:00
Praveen G 7a91794d5b [Flang][OpenMP] Add semantic checks for OpenMP Private clause.
Add the semantic checks for the OpenMP 4.5 - 2.15.3.3 Private clause.

1. Pointers with the INTENT(IN) attribute may not appear in a private clause.
2. Variables that appear in namelist statements may not appear in a private clause.
   A flag 'InNamelist' is added to the Symbol::Flag to identify the symbols
   in Namelist statemnts.

Test cases : omp-private01.f90, omp-private02.f90

Reviewed By: kiranchandramohan

Differential Revision: https://reviews.llvm.org/D90210
2020-11-30 11:46:36 -05:00
peter klausler 5349f99114 [flang] Correct handling of null pointer initializers
Fortran defines "null-init" null pointer initializers as
being function references, syntactically, that have to resolve
to calls to the intrinsic function NULL() with no actual
arguments.

Differential revision: https://reviews.llvm.org/D91657
2020-11-18 13:57:25 -08:00
Peter Steinfeld 681978d3b4 [flang] Duplicate names for ac-implied-do variables erroneously cause errors
According to section 19.4, paragraph 5, the scope of an ac-implied-do variable
is the enclosing ac-implied-do.  But we were not creating new scopes upon
entry to an ac-implied-do.  This was causing error messages to be erroneously
emitted.

I fixed, the code, added a test to array-constr-values.f90, added the test
folding15.f90 and corrected the test symbol05.f90.

Differential Revision: https://reviews.llvm.org/D91560
2020-11-16 18:57:13 -08:00
peter klausler 2d5b850751 [flang] Use IMPLICIT from scope of external function reference
Implicitly typed references to external functions are applying
the IMPLICIT typing rules of the global scope in which their
symbols were created, not the IMPLICIT typing rules in force in
the scope from which they were referenced.

Differential revision: https://reviews.llvm.org/D91214
2020-11-11 12:12:24 -08:00
peter klausler 882fa241f1 [flang] Better error messages & more cases caught for bad forward refs
Subclause 10.1.12 in F'2018 prohibits forward references from
a specification expression to an object declared later in the
same specification part.  Catch this error better and emit
specific error messages about the violation.

Differential revision: https://reviews.llvm.org/D90492
2020-10-30 17:11:37 -07:00
Jean Perier 878b526409 [flang] Tighten rules to resolve procedure as intrinsic procedure
2 Bug fixes:

- Do not resolve procedure as intrinsic if they appeared in an
  EXTERNAL attribute statement (one path was not considering this flag)

- Emit an error if a procedure resolved to be an intrinsic function
  (resp. subroutine) is used as a subroutine (resp. function).
  Lowering was attempted while the evaluate::Expression for the
  call was missing without any errors.

1 behavior change:

- Do not implicitly resolve subroutines (resp. functions) as intrinsics
  because their name is the name of an intrinsic function (resp.
  subroutine). Add justification in documentation.

Reviewed By: klausler, tskeith

Differential Revision: https://reviews.llvm.org/D90049
2020-10-26 11:25:40 +01:00
Peter Steinfeld 29d838310d [flang] Fix call to CHECK() on erroneous subroutine declaration
When processing declarations in resolve-names.cpp, we were returning a
symbol that had SubprogramName details to PushSubprogramScope(), which
expects a symbol with Subprogram details.

I adjusted the code and added a test.

Differential Revision: https://reviews.llvm.org/D89829
2020-10-20 18:09:15 -07:00
peter klausler 37b2e2b04c [flang] Semantic analysis for FINAL subroutines
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
2020-09-30 15:46:15 -07:00
Tim Keith 82edd428f1 [flang] Fix check for distinguishable operators/assignments
Change how generic operators and assignments are checked for
distinguishable procedures. Because of how they are invoked, available
type-bound generics and normal generics all have to be considered
together. This is different from how generic names are checked.

Move common part of checking into DistinguishabilityHelper so that it
can be used in both cases after the appropriate procedures have been
added.

Cache result of Procedure::Characterize(Symbol) in a map in
CheckHelper so that we don't have to worry about passing the
characterized Procedures around or the cost of recomputing them.

Add MakeOpName() to construct names for defined operators and assignment
for using in error messages. This eliminates the need for different
messages in those cases.

When the procedures for a defined operator or assignment are undistinguishable,
include the type name in the error message, otherwise it may be ambiguous.

Add missing check that procedures for defined operators are functions
and that their dummy arguments are INTENT(IN) or VALUE.

Differential Revision: https://reviews.llvm.org/D87341
2020-09-10 07:22:55 -07:00