Commit Graph

122 Commits

Author SHA1 Message Date
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