Pointer components without default initialization pose some
difficult (or impossible) problems when they appear as right-hand
side targets in pointer assignment statements; they may contain
garbage or stale data that looks enough like a valid descriptor
to cause a crash. Solve the problem by avoiding it -- ensure
that pointers' descriptors are at least minimally established.
Differential Revision: https://reviews.llvm.org/D149979
A fairly recent introduction of runtime I/O APIs called OutputDerivedType()
and InputDerivedType() didn't cover NAMELIST I/O's need to access
non-type-bound generic interfaces for user-defined derived type I/O
when those generic interfaces are defined in some scope other than the
one that defines the derived type.
The patch adds a new data structure shared between lowering
and the runtime that can represent all of the cases that can
arise with non-type-bound defined I/O. It can represent
scopes in which non-type-bound defined I/O generic interfaces
are inaccessible, too, due to IMPORT statements.
The data structure is now an operand to OutputDerivedType() and
InputDerivedType() as well as a data member in the NamelistGroup
structure.
Differential Revision: https://reviews.llvm.org/D148257
Many semantic checks for constraints related to PURE subprograms
can be implemented in terms of Semantics' "definable.h" utilities,
slightly expanded. Replace some particular PURE constraint
checks with calls to WhyNotDefinable(), except for cases that
had better specific error messages, and start checking some
missing constraints with DEALLOCATE statements and local
variable declarations.
Differential Revision: https://reviews.llvm.org/D147389
The utility routine in semantics that determines whether an
executable construct constitutes an image control statement
was not examining the single action statement controlled by
a non-construct IF statement, e.g. 'IF(P) STOP'.
Differential Revision: https://reviews.llvm.org/D146584
The present I/O infrastructure for user-defined derived type I/O
subroutines works fine for type-bound I/O generic bindings. It also works
for explicit INTERFACE blocks and GENERIC statements that define
UDDIO subroutines in the same scope as the definition of the derived type,
so long as the specific procedures in those bindings are module procedures
or external procedures.
For non-type-bound UDDTIO specific procedures that are dummy procedures,
thunks of inner procedures, or procedure pointers, or that are defined with
interfaces or GENERIC outside the scope of the definition of the derived
type, a new runtime I/O API is needed so that lowering can generate
a call that supplies the appropriate procedure as well as the defined
type instance.
This patch specifies and implements this new runtime API and provides
utility routines for lowering to use to determine whether it should be
called for any particular OutputItem or InputItem in the parse tree.
Differential Revision: https://reviews.llvm.org/D146571
Non-DEFERRED procedure binding checking can't blindly accept
all procedures defined in modules -- they can't be ABSTRACT
interfaces. And GetUltimate() must be used rather than
FindSubprogram(); the latter will resolve to a procedure's
interface in the case of "procedure(interface) :: external",
not "external".
Differential Revision: https://reviews.llvm.org/D145749
When a parameterized derived type has FINAL subroutines, only
those FINAL subroutines whose dummy argument's type matches the
type parameter values of a particular instantiation are relevant
to that instantiation.
Differential Revision: https://reviews.llvm.org/D145741
If the interface specifies BIND(C), then the declarations using
this interface inherit BIND(C), and if they are referenced via use
association they must be classified as BIND(C) subprograms.
Differential Revision: https://reviews.llvm.org/D145084
When a descriptor inquiry or inquiry function's result is
not constant and is known to be impossible to correctly determine
at runtime, raise an error. For example, LEN(X) when X is
a local allocatable variable with deferred length.
Differential Revision: https://reviews.llvm.org/D142759
This patch implements the derived-type finalization for
monomorphic and polymorphic derived-type.
The finalization is done through a call to the `Destroy`
runtime function so the allocatable component object are also
finalized correctly when needed. It would be possible to finalize
monomorphic derived-type with non finalizable component with a
direct call to their finalize subroutine.
7.5.6.3 point 1: LHS nonallocatable object and LHS allocatable
object finalization. Done with call to `Destroy` for monomorphic
derived-type and through `Assign` for polymorphic entities.
7.5.6.3 point 2: Done within the deallocation calls.
7.5.6.3 point 3: A function context is added to the bridge to
attach finalization that need to happen on function/subroutine
exit.
7.5.6.3 point 4: BLOCK construct not yet implemented.
7.5.6.3 point 5/6: Finalization attach to the stmtCtx in a
similar way than 9.7.3.2 point 4.
7.5.6.3 point 7: INTENT(OUT) finalization done with a
call to `Destroy` runtime function call.
This patch passes 9/10 tests in the proposed test-suite
https://github.com/llvm/llvm-test-suite/pull/13
- The case with BLOCK construct will be implemented later when
BLOCK are implemented upstream.
- Automatic deallocation is not yet implemented. Finalization triggered
by automatic deallocation is then not triggered.
Reviewed By: jeanPerier, PeteSteinfeld
Differential Revision: https://reviews.llvm.org/D142707
The ProcInterface structure is used only by ProcEntityDetails; it represents
what a program might have put in parentheses in a procedure-declaration-stmt,
either the name of a procedure interface or a declaration-type-spec.
If a procedure entity has an implicit interface, the function result
type (if any) can be kept in EntityDetails::type_, which already exists
and is currently redundant for ProcEntityDetails symbols.
All that is really needed is a nullable Symbol pointer in ProcEntityDetails
to point to the procedure's explicit interface, when it has one.
Also, catch the case where a procedure has an explicit interface
and a program attempts to also give it a type.
Differential Revision: https://reviews.llvm.org/D140134
In a pure context, a pointer acquired from an INTENT(IN) dummy argument
may not be copied. Catch the case in which the pointer is a component
of an allocatable component at some depth of nesting.
(This patch adds a new component iterator kind that is a variant of
a potential subobject component iterator; it visits all potential
subobject components, plus pointers, into which it does not descend.)
Differential Revision: https://reviews.llvm.org/D139161
Type-bound generics like operator(+) and assignment(=) need to not be
PRIVATE if they are used outside the module in which they are declared.
Differential Revision: https://reviews.llvm.org/D139123
12.6.3p5 requires an I/O data list item to have a defined I/O procedure
if it is polymorphic. (We could defer this checking to the runtime,
but no other Fortran compiler does so, and we would also have to be
able to catch the case of an allocatable or pointer direct component
in the absence of a defined I/O subroutine.)
Also includes a patch to name resolution that ensures that a
SELECT TYPE construct entity is polymorphic in the domain of a
CLASS IS guard.
Also ensures that non-defined I/O of types with PRIVATE components
is caught.
Differential Revision: https://reviews.llvm.org/D139050
When a scope declares the name and perhaps some characteristics of
an external subprogram using any of the many means that Fortran supplies
for doing such a thing, and that external subprogram's definition is
available, check the local declaration against the external definition.
In particular, if the global definition's interface cannot be called
by means of an implicit interface, ensure that references are via an
explicit and compatible interface.
Further, extend call site checking so that when a local declaration
exists for a known global symbol and the arguments are valid for that
local declaration, the arguments are checked against the global's
interface, just are is already done when no local declaration exists.
Differential Revision: https://reviews.llvm.org/D139042
The infrastructure in semantics that is used to check that the
left-hand sides of normal assignment statements are really definable
variables was not being used to check whether the LHSs of pointer assignments
are modifiable, and so most cases of unmodifiable pointers are left
undiagnosed. Rework the semantics checking for pointer assignments,
NULLIFY statements, pointer dummy arguments, &c. so that cases of
unmodifiable pointers are properly caught. This has been done
by extracting all the various definability checking code that has
been implemented for different contexts in Fortran into one new
facility.
The new consolidated definability checking code returns messages
meant to be attached as "because: " explanations to context-dependent
errors like "left-hand side of assignment is not definable".
These new error message texts and their attached explanations
affect many existing tests, which have been updated. The testing
infrastructure was extended by another patch to properly compare
warnings and explanatory messages, which had been ignored until
recently.
Differential Revision: https://reviews.llvm.org/D136979
The code snippet
module m
interface
module subroutine specific
end subroutine
end interface
interface generic
module procedure specific
end interface
end module
elicits a bogus semantic error about "specific" not being an acceptable
module procedure for the generic interface; fix.
Differential Revision: https://reviews.llvm.org/D134402
Procedure bindings with explicit interfaces don't work when the
interface is shadowed by a generic interface of the same name,
and can produce spurious semantic error messages. Extend the
characterization and checking code for such things, and the utility
functionns on which they depend, to dig through generics when they
occlude interface-defining subprograms. This is done on demand in
checking code, not once during name resolution, because the
procedures in question may also be forward-referenced.
Differential Revision: https://reviews.llvm.org/D131105
diff --git a/flang/include/flang/Semantics/symbol.h b/flang/include/flang/Semantics/symbol.h
index e79f8ab6503e..0b03bf06eb73 100644
--- a/flang/include/flang/Semantics/symbol.h
We need to distinguish BLOCK host association from subprogram host
association when checking assignments in PURE subprograms.
The specific case that is not allowed is an assignment to a variable
from the scope around the PURE subprogram.
Differential Revision: https://reviews.llvm.org/D131098
The predicate IsHostAssocited() was implemented in a way that would
return true only for cases of host association into a module or inner
subprogram. Technically, the use of a name in a BLOCK construct
that is not declared therein is considered in the Fortran standard
to also be a form of host association, and this matters when doing
error checking on DATA statements.
Differential Revision: https://reviews.llvm.org/D130388
If BIND(C) appears on an internal procedure, it must have a null binding
label, i.e. BIND(C,NAME="").
Also address conflicts with D127725 which was merged during development.
Differential Revision: https://reviews.llvm.org/D128676
The predicate that determines image control statements needs
to distinguish STOP (which is) from ERROR STOP (which isn't).
Differential Revision: https://reviews.llvm.org/D127796
When two or more generic interfaces are available by declaration or
by USE association at different scoping levels, we need to search
the outer generic interfaces as well as the inner ones, but only after
the inner ones have failed to produce a specific procedure that matches
a given set of actual arguments. This means that it is possible for
a specific procedure of a generic interface of an inner scope to override
a conflicting specific procedure of a generic interface of an outer
scope.
Also cope with forward references to derived types when a generic
interface is also in scope.
Fixes LLVM bug https://github.com/llvm/llvm-project/issues/55240 and
LLVM bug https://github.com/llvm/llvm-project/issues/55300.
Differential Revision: https://reviews.llvm.org/D126587
A utility predicate in semantics was incorrectly determining that
an INTERFACE ASSIGNMENT(=) (or other form of generic) could not have
a specific procedure with an unlimited polymorphic second argument.
This led to a crash later in expression analysis. Fix, and
extend tests.
Differential Revision: https://reviews.llvm.org/D126151
Forward references to ENTRY names to pass them as actual procedure arguments
don't work in all cases, exposing some basic ordering problems in
name resolution for these symbols. Refactor; create all the
necessary procedure symbols, and either function result or host association
symbols (for subroutines), at the time that the subprogrma scope is
created, so that the names exist in the scope as text "before"
the ENTRY is processed in name resolution. Some processing
remains in PostEntryStmt() so that we can check that an ENTRY with
an explicit distinct RESULT doesn't also have declarations for the
ENTRY name.
Differential Revision: https://reviews.llvm.org/D126142
As is already supported for dummy procedures, we need to also accept
declarations of procedure pointers that consist of a POINTER attribute
statement followed by an INTERFACE block. (The case of an INTERFACE
block followed by a POINTER statement already works.)
While cleaning this case up, adjust the utility predicate IsProcedurePointer()
to recognize it (namely a SubprogramDetails symbol with Attr::POINTER)
and delete IsProcName(). Extend tests, and add better comments to
symbol.h to document the two ways in which procedure pointers are
represented.
Differential Revision: https://reviews.llvm.org/D125139
The semantic test for an intrinsic assignment to a polymorphic
derived type entity from a type that is an extension of its base
type was reversed, so it would allow assignments that it shouldn't
and disallowed some that it should; and the test case for it
incorectly assumed that the invalid semantics were correct.
Fix the code and the test, and add a new test for the invalid
case (LHS type is an extension of the RHS type).
Differential Revision: https://reviews.llvm.org/D125135
Adds flang/include/flang/Common/log2-visit.h, which defines
a Fortran::common::visit() template function that is a drop-in
replacement for std::visit(). Modifies most use sites in
the front-end and runtime to use common::visit().
The C++ standard mandates that std::visit() have O(1) execution
time, which forces implementations to build dispatch tables.
This new common::visit() is O(log2 N) in the number of alternatives
in a variant<>, but that N tends to be small and so this change
produces a fairly significant improvement in compiler build
memory requirements, a 5-10% improvement in compiler build time,
and a small improvement in compiler execution time.
Building with -DFLANG_USE_STD_VISIT causes common::visit()
to be an alias for std::visit().
Calls to common::visit() with multiple variant arguments
are referred to std::visit(), pending further work.
This change is enabled only for GCC builds with GCC >= 9;
an earlier attempt (D122441) ran into bugs in some versions of
clang and was reverted rather than simply disabled; and it is
not well tested with MSVC. In non-GCC and older GCC builds,
common::visit() is simply an alias for std::visit().
Prior to this patch, the semantics utility GetExpr() will crash
unconditionally if it encounters a typed expression in the parse
tree that has not been set by expression semantics. This is the
right behavior when called from lowering, by which time it is known
that the program had no fatal user errors, since it signifies a
fatal internal error. However, prior to lowering, in the statement
semantics checking code, a more nuanced test should be used before
crashing -- specifically, we should not crash in the face of a
missing typed expression when in error recovery mode.
Getting this right requires GetExpr() and its helper class to have
access to the semantics context, so that it can check AnyFatalErrors()
before crashing. So this patch touches nearly all of its call sites.
Differential Revision: https://reviews.llvm.org/D123873
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
Adds flang/include/flang/Common/visit.h, which defines
a Fortran::common::visit() template function that is a drop-in
replacement for std::visit(). Modifies most use sites in
the front-end and runtime to use common::visit().
The C++ standard mandates that std::visit() have O(1) execution
time, which forces implementations to build dispatch tables.
This new common::visit() is O(log2 N) in the number of alternatives
in a variant<>, but that N tends to be small and so this change
produces a fairly significant improvement in compiler build
memory requirements, a 5-10% improvement in compiler build time,
and a small improvement in compiler execution time.
Building with -DFLANG_USE_STD_VISIT causes common::visit()
to be an alias for std::visit().
Calls to common::visit() with multiple variant arguments
are referred to std::visit(), pending further work.
Differential Revision: https://reviews.llvm.org/D122441
Assignment semantics was coughing up bad errors and crashes for
intrinsic assignments to unlimited polymorphic entities while
looking for any (impossible) user defined ASSIGNMENT(=) generic
or intrinsic type conversion.
Differential Revision: https://reviews.llvm.org/D122440
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
Derived types with allocatable and pointer components cannot
be used in I/O data transfer statements unless they have defined
I/O procedures available (as type-bound or regular generics).
These cases are caught as errors by the I/O runtime library,
but it would be better if they were flagged during compilation.
(Address comment in review: don't use explicit name string lengths.)
Differential Revision: https://reviews.llvm.org/D120675
While one cannot of course statically initialize an allocatable component
of an instance of a derived type, its mere presence should not prevent
DATA initialization of the other nonallocatable components. Semantics
was treating the existence of an allocatable component as a case of
"default initialization", which it is, but not one that should run
afoul of C877. Add another Boolean argument to IsInitialized() to allow
for a more nuanced test.
Differential Revision: https://reviews.llvm.org/D119449
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
Subclause 7.5.2.4 lists conditions under which two distinct derived
types are to be considered the same type for purposes of argument
association, assignment, and so on. These conditions are implemented
in evaluate::IsTkCompatibleWith(), but assignment semantics doesn't
use it for testing for intrinsic assignment compatibility. Fix that.
Differential Revision: https://reviews.llvm.org/D117621
When a scalar-valued function with no distinct RESULT
is being called recursively in its own executable part,
emit a better message about the error. Clean up the
code that resolves function vs. array ambiguities in
expression semantics.
Update to address review comment
Differential Revision: https://reviews.llvm.org/D117577
A 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
The predicate IsCoarray() needs to be in libFortranEvaluate so that
IsSaved() can call it without breaking the shared library build.
Pushed without pre-commit review as I'm moving code around and
the fix to the shared build is confirmed.
This legacy option (available in other Fortran compilers with various
spellings) implies the SAVE attribute for local variables on subprograms
that are not explicitly RECURSIVE. The SAVE attribute essentially implies
static rather than stack storage. This was the default setting in Fortran
until surprisingly recently, so explicit SAVE statements & attributes
could be and often were omitted from older codes. Note that initialized
objects already have an implied SAVE attribute, and objects in COMMON
effectively do too, as data overlays are extinct; and since objects that are
expected to survive from one invocation of a procedure to the next in static
storage should probably be explicit initialized in the first place, so the
use cases for this option are somewhat rare, and all of them could be
handled with explicit SAVE statements or attributes.
This implicit SAVE attribute must not apply to automatic (in the Fortran sense)
local objects, whose sizes cannot be known at compilation time. To get the
semantics of IsSaved() right, the IsAutomatic() predicate was moved into
Evaluate/tools.cpp to allow for dynamic linking of the compiler. The
redundant predicate IsAutomatic() was noticed, removed, and its uses replaced.
GNU Fortran's spelling of the option (-fno-automatic) was added to
the clang-based driver and used for basic sanity testing.
Differential Revision: https://reviews.llvm.org/D114209
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
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
Define an API for, and implement, runtime support for arbitrary
assignment of one descriptor's data to another, with full support for
(re)allocation of allocatables with finalization when necessary,
user-defined derived type assignment TBP calls, and intrinsic (default)
componentwise assignment of derived type instances with allocation of
automatic components. Also clean up API and implementation of
finalization/destruction using knowledge gained while studying
edge cases for assignment in the 2018 standard.
The look-up procedure for special procedure bindings in derived
types has been optimized from O(N) to O(1) since it will probably
matter more. This required some analysis in runtime derived type
description table construction in semantics and some changes to the
table schemata.
Executable Fortran tests have been developed; they'll be added
to the test base once they can be lowered and run by f18.
Differential Revision: https://reviews.llvm.org/D107678
