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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
`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
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
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
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
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
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
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
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
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
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
When an error is associated with a symbol, it was marked with a flag
from Symbol::Flag. The problem with that is that you need a mutable
symbol to do that. Instead, store the set of error symbols in the
SemanticsContext. This allows for some const_casts to be eliminated.
Also, improve the internal error that occurs if SetError is called
but no fatal error has been reported.
Differential Revision: https://reviews.llvm.org/D86740
Accept and represent "global" compiler directives that appear
before and between program units in a source file.
Differential Revision: https://reviews.llvm.org/D86555
A specification expression can reference an implicitly declared variable
in the host procedure. Because we have to process specification parts
before execution parts, this may be the first time we encounter the
variable. We were assuming the variable was implicitly declared in the
scope where it was encountered, leading to an error because local
variables may not be referenced in specification expressions.
The fix is to tentatively create the implicit variable in the host
procedure because that is the only way the specification expression can
be valid. We mark it with the flag `ImplicitOrError` to indicate that
either it must be implicitly defined in the host (by being mentioned in
the execution part) or else its use turned out to be an error.
We need to apply the implicit type rules of the host, which requires
some changes to implicit typing.
Variables in common blocks are allowed to appear in specification expressions
(because they are not locals) but the common block definition may not appear
until after their use. To handle this we create common block symbols and object
entities for each common block object during the `PreSpecificationConstruct`
pass. This allows us to remove the corresponding code in the main visitor and
`commonBlockInfo_.curr`. The change in order of processing causes some
different error messages to be emitted.
Some cleanup is included with this change:
- In `ExpressionAnalyzer`, if an unresolved name is encountered but
no error has been reported, emit an internal error.
- Change `ImplicitRulesVisitor` to hide the `ImplicitRules` object
that implements it. Change the interface to pass in names rather
than having to get the first character of the name.
- Change `DeclareObjectEntity` to have the `attrs` argument default
to an empty set; that is the typical case.
- In `Pre(parser::SpecificationPart)` use "structured bindings" to
give names to the pieces that make up a specification-part.
- Enhance `parser::Unwrap` to unwrap `Statement` and `UnlabeledStatement`
and make use of that in PreSpecificationConstruct.
Differential Revision: https://reviews.llvm.org/D86322
When we report an error for a bad character kind, don't keep it in the
`DeclTypeSpec`. Otherwise there could be further problems. In this case,
`ComputeOffsets()` got an assertion error because we didn't recognize
`CHARACTER(*,8)` as needing a descriptor because of the bad kind.
Fixes https://bugs.llvm.org/show_bug.cgi?id=47173
Differential Revision: https://reviews.llvm.org/D86357
As with use-associated symbols, copy the attributes and flags from the
original symbol onto host-associated symbols when they are created.
This was showing up as an error on a deallocate of a host-associated
name. We reported an error because the symbol didn't have the POINTER
or ALLOCATABLE attribute.
Differential Revision: https://reviews.llvm.org/D85763
If an unrestricted specific intrinsic function name is first encountered
as an actual argument, it should be interpreted as an object entity,
not a procedure entity.
Fix some tests that depended on the previous interpretation by adding
explicit INTRINSIC statements.
Differential Revision: https://reviews.llvm.org/D85792
Allow compiler directives in the implicit-part and before USE statements
in the specification-part.
Differential Revision: https://reviews.llvm.org/D85693
Add `-fimplicit-none-type-always` to treat each specification-part
like it has `IMPLICIT NONE`. This is helpful for enforcing good Fortran
programming practices. We might consider something similar for
`IMPLICIT NONE(EXTERNAL)` as well.
Add `-fimplicit-none-type-never` to ignore occurrences of `IMPLICIT NONE`
and `IMPLICIT NONE(TYPE)`. This is to handle cases like the one below,
which violates the standard but it accepted by some compilers:
```
subroutine s(a, n)
implicit none
real :: a(n)
integer :: n
end
```
Differential Revision: https://reviews.llvm.org/D85363
When declaring the same variable twice with an initialization, we were failing
an internal check. I fixed this by checking to see if the associated symbol
already had an error.
I added tests for pointer and non-pointer initialization of duplicate names.
Differential Revision: https://reviews.llvm.org/D84969
To make it easier for lowering to identify which symbols from the host
are captured by internal subprograms, create HostAssocDetails for them.
In particular, if a symbol is referenced and it is contained in a
subprogram or main program that is not the same as the containing
program unit of the reference, a HostAssocDetails symbol is created
in the current scope.
Differential Revision: https://reviews.llvm.org/D84889
When an instrinsic function is declared in a type declaration statement
we need to set the INTRINSIC attribute and (per 8.2(3)) ignore the
specified type.
To simplify the check, add IsIntrinsic utility to BaseVisitor.
Also, intrinsics and external procedures were getting assigned a size
and offset and they shouldn't be.
Differential Revision: https://reviews.llvm.org/D84702
Move `ResolveAccParts` and `ResolveOmpParts` from resolve-names.cpp to
resolve-directives.{h,cpp}. Move the implementation in the classes
`DirectiveAttributeVisitor`, `AccAttributeVisitor`, and
`OmpAttributeVisitor` to resolve-directives.cpp as well.
To allow this to happen, move `EvaluateIntExpr` and introduce
`EvaluateInt64` to resolve-names-utils.h. The latter is also useful
elsewhere in resolve-names.cpp for converting an Expr to std::int64_t.
The other problem was that `ResolveDesignator` was called from the code
that was moved. At the moment it doesn't seem to be doing anything so I
removed the calls (and no tests failed). If it proves to be needed, we
can either resolve those designators in resolve-names.cpp or pass the
`ResolveDesignator` function in to the code that needs to call it.
Differential Revision: https://reviews.llvm.org/D84768
If a symbol (that is not a dummy argument) is implicitly declared inside
a statement function, don't create it in the statement function's scope.
Instead, treat statement functions like blocks when finding the inclusive
scope and create the symbol there.
Add a new flag, StmtFunction, to symbols that represent statement functions.
Differential Revision: https://reviews.llvm.org/D84588
The result of a statement function may require an implicit conversion
to match its result type. Add that to the expression that represents
the statement function body in SubprogramDetails.
Extract the analysis of that expression into a separate function.
Dump the statement function expression as part of the dump of
SubprogramDetails.
Differential Revision: https://reviews.llvm.org/D84452
When an intrinsic is referenced in a module scope, a symbol for it is
added. When that module is USEd, the intrinsic should not be included.
Otherwise we can get ambiguous reference errors with the same intrinsic
coming from two difference modules.
Differential Revision: https://reviews.llvm.org/D83905
