F18 preserves lower bounds of explicit-shape named constant arrays, but
failed to also do so for implicit-shape named constants. Fix.
Differential Revision: https://reviews.llvm.org/D127021
Inquiries into the bounds, size, and length of local variables (and function results)
are acceptable specification expressions. A recent change allowed them for dummy
arguments that are not OPTIONAL or INTENT(OUT), but didn't address other object
entities.
Differential Revision: https://reviews.llvm.org/D125343
The rules in the Fortran standard for specification expressions
are full of special cases and exceptions, and semantics didn't get
them exactly right. It is valid to refer to an INTENT(OUT) dummy
argument in a specification expression in the context of a
specification inquiry function like SIZE(); it is not valid to
reference an OPTIONAL dummy argument outside of the context of
PRESENT. This patch makes the specification expression checker
a little context-sensitive about whether it's examining an actual
argument of a specification inquiry intrinsic function or not.
Differential Revision: https://reviews.llvm.org/D125131
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().
In case a character component PDT length only depends on kind parameters,
fold it while instantiating the PDT. This is especially important if the
component has an initializer because later semantic phases (offset
computation or runtime type info generation) might get confused and
generate offset/type info that will lead to crashes in lowering.
Differential Revision: https://reviews.llvm.org/D122938
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
Similarly to LBOUND in https://reviews.llvm.org/D121488, UBOUND must
return zero for an empty dimension, no matter the specification
expression.
Add a GetUBOUND method to be used in expression rewrite that prevents
folding UBOUND to a bound specification expression if the extent is
not a compile time constant.
Fold the case where the extents is known to be zero (and also deal with
this case in LBOUND since we can and should to comply with constant
expression requirements).
Differential Revision: https://reviews.llvm.org/D122242
LBOUND must return 1 for an empty dimension, no matter what
explicit expression might appear in a declaration or arrive in
a descriptor.
Differential Revision: https://reviews.llvm.org/D121488
Using recently established message severity codes, upgrade
non-fatal messages to usage and portability warnings as
appropriate.
Differential Revision: https://reviews.llvm.org/D121246
When a structure constructor does not initialize an allocatable component,
ensure that the typed expression representation contains an explicit
NULL() for the component. Expression semantics already copies default
initialized expressions for nonallocatable components into structure
constructors. This change is expected to simplify lowering.
Differential Revision: https://reviews.llvm.org/D121162
The predicate IsInitialDataTarget() was failing to return a correct true
result in the case of a reference to the intrinsic function NULL() with a
MOLD= argument. Fix, and improve tests for "NULL()" elsewhere in semantics,
checking for an attribute set by intrinsics.cpp rather than the actual name.
Differential Revision: https://reviews.llvm.org/D119452
When a scope's symbol has characteriztics whose specification
expressions depend on other non-constant symbols in the same scope,
f18 rightfully emits an error. However, in the case of usage in
specification expressions involving host association, the program is not
invalid. This can arise, for example, in the case of an internal
function whose result's attributes use host-associated variables.
Differential Revision: https://reviews.llvm.org/D119565
We already accept assignments of INTEGER to LOGICAL (& vice versa)
as an extension, but not initialization. Extend initialization
to cover those cases.
(Also fix misspelling in nearby comment as suggested by code reviewer.)
Decouple an inadvertent dependence cycle by moving two
one-line function definitions into a header file.
Differential Revision: https://reviews.llvm.org/D117159
Some kinds of Fortran arrays are declared with the same syntax,
and it is impossible to tell from a shape (:, :) or (*) whether
the object is assumed shape, deferred shape, assumed size, implied
shape, or whatever without recourse to more information about the
symbol in question. This patch softens the names of some predicate
functions (IsAssumedShape to CanBeAssumedShape) and makes others
more reflective of the syntax they represent (isAssumed to isStar)
in an attempt to encourage coders to seek and find definitive
predicate functions whose names deliver what they seem to mean.
Address TODO comments in IsSimplyContiguous() by using the
updated IsAssumedShape() predicate.
Differential Revision: https://reviews.llvm.org/D114829
The current code was relying on the fact that allocatables are deferred
shape and that isAssumedShape() should therefore return true for them.
This is not true, because the current parsing/semantic analysis always
builds a semantics::ArraySpec for `x(:)` that returns true to both
isDeferredShape()/isAssumedShape(), whether x is allocatable/pointer or
not.
It proved tricky to change this behavior, so this is a simple fix for
IsSymplyContiguous where it currently matters, but we most likely want
to investigate more and fix the isDeferredShape()/isAssumedShape() in
a second time.
Differential Revision: https://reviews.llvm.org/D114599
Previous code was returning true for `x(:)` where x is a pointer without
the contiguous attribute.
In case the array ref is a whole array section, check the base for contiguity
to solve the issue.
Differential Revision: https://reviews.llvm.org/D114084
When an array's shape involves references to symbols that are not
invariant in a scope -- the classic example being a dummy array
with an explicit shape involving other dummy arguments -- the
compiler was creating shape expressions that referenced those
symbols. This might be valid if those symbols are somehow
captured and copied at each entry point to a subprogram, and
the copies referenced in the shapes instead, but that's not
the case.
This patch introduces a new expression predicate IsScopeInvariantExpr(),
which defines a class of expressions that contains constant expressions
(in the sense that the standard uses that term) as well as references
to items that may be safely accessed in a context-free way throughout
their scopes. This includes dummy arguments that are INTENT(IN)
and not VALUE, descriptor inquiries into descriptors that cannot
change, and bare LEN type parameters within the definitions of
derived types. The new predicate is then used in shape analysis
to winnow out results that would have otherwise been contextual.
Differential Revision: https://reviews.llvm.org/D113309
The Fortran 2018 standard defines the concept of simple contiguity
in subclause 9.5.4 as a characteristic of arrays. So that scalars
may also be used in contexts where simply contiguous arrays are
allowed, f18 treats them as single-element arrays that are trivially
contiguous. This patch documents this semantic extension and
also adds comments to the predicate that implements the concept.
Differential Revision: https://reviews.llvm.org/D111679
The THEN keyword in the "ELSE IF (test) THEN" statement is useless
syntactically, and to omit it is a common error (at least for me!)
that has poor error recovery. This patch changes the parser to
cough up a simple "expected 'THEN'" and still recognize the rest of
the IF construct.
Differential Revision: https://reviews.llvm.org/D110952
A function can't be a specification function if it has a dummy procedure
argument, even if it's optional and unused. So don't check the reference
for actual procedure arguments, but rather the characteristics of the
function.
Differential Revision: https://reviews.llvm.org/D109935
Dummy procedures can be defined as subprograms with explicit
interfaces, e.g.
subroutine subr(dummy)
interface
subroutine dummy(x)
real :: x
end subroutine
end interface
! ...
end subroutine
but the symbol table had no means of marking such symbols as dummy
arguments, so predicates like IsDummy(dummy) would fail. Add an
isDummy_ flag to SubprogramNameDetails, analogous to the corresponding
flag in EntityDetails, and set/test it as needed.
Differential Revision: https://reviews.llvm.org/D106697
The result expression for the analysis of a Component is not (longer)
valid in the expression traversal framework used by IsSimplyContiguousHelper
now that it has a tri-state result. Fix so that any result of
analyzing the component symbol is required to be true, not just
present.
Differential Revision: https://reviews.llvm.org/D106693
To ensure that errors are emitted by CheckConformance and
its callers in all situations, it's necessary for the returned result
of that function to distinguish between three possible
outcomes: the arrays are known to conform at compilation time,
the arrays are known to not conform (and a message has been
produced), and an indeterminate result in which is not possible
to determine conformance. So convert CheckConformance's
result into an optional<bool>, and convert its confusing
Boolean flag arguments into a bit-set of named flags too.
Differential Revision: https://reviews.llvm.org/D103654
f18 was emitting a bogus error message about the lack of a TARGET
attribute when a pointer was initialized with a component of a
variable that was a legitimate TARGET.
Differential Revision: https://reviews.llvm.org/D99665
There were two problems with constant arrays whose lower bound is not 1.
First, when folding the arrays, we were creating the folded array to have lower
bounds of 1 but, we were not re-adjusting their lower bounds to the
declared values. Second, we were not calculating the extents correctly.
Both of these problems led to bogus error messages.
I fixed the first problem by adjusting the lower bounds in
NonPointerInitializationExpr() in Evaluate/check-expression.cpp. I wrote the
class ArrayConstantBoundChanger, which is similar to the existing class
ScalarConstantExpander. In the process of implementing and testing it, I found
a bug that I fixed in ScalarConstantExpander which caused it to infinitely
recurse on parenthesized expressions. I also removed the unrelated class
ScalarExpansionVisitor, which was not used.
I fixed the second problem by changing the formula that calculates upper bounds
in in the function ComputeUpperBound() in Evaluate/shape.cpp.
I added tests that trigger the bogus error messages mentioned above along with
a constant folding tests that uses array operands with shapes that conform but
have different bounds.
In the process of adding tests, I discovered that tests in
Evaluate/folding09.f90 and folding16.f90 were written incorrectly, and I
fixed them. This also revealed a bug in contant folding of the
intrinsic "lbounds" which I plan to fix in a later change.
Differential Revision: https://reviews.llvm.org/D95449
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
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
Remove resolved & moot TODO comments in Common/, Parser/,
and Evaluate/. Address a pending one relating to parsing
ambiguity in DATA statement constants, handling it with
symbol table information in Semantics and adding a test.
Differential Revision: https://reviews.llvm.org/D93323
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
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
Avoid a spurious error message about a dummy procedure reference
in a specification expression by restructuring the handling of
use-associated and host-associated symbols.
Updated to fix a circular dependence between shared library
binaries that was introduced by the original patch.
Differential revision: https://reviews.llvm.org/D91286
Avoid a spurious error message about a dummy procedure reference
in a specification expression by restructuring the handling of
use-associated and host-associated symbols.
Differential revision: https://reviews.llvm.org/D91209
Change the expression representation TypeParamInquiry from being
a class that's templatized on the integer KIND of its result into
a monomorphic representation that results in a SubscriptInteger
that can then be converted.
This is a minor simplification, but it's worth doing because
it is believed to also be a work-around for bugs in the MSVC
compiler with overload resolution that affect the expression
traversal framework.
Differential Revision: https://reviews.llvm.org/D86551
I fixed an assert caused by passing an empty array as the source= argument to
RESHAPE(). In the process, I noticed that there were no tests for RESHAPE(),
so I wrote a test that covers all the description in 16.9.163. In the process,
I made the error messages more consistent and descriptive. I also changed the
test to see if a reference to an intrinsic function was a constant to say that
it is a constant if it's a refererence to an invalid intrinsic. This avoids
emitting multiple messages for the same erroneous source.
Differential Revision: https://reviews.llvm.org/D84904
Rolls up small changes across the frontend to prepare for the large
forthcoming patch (part 4/4) that completes DATA statement processing
via conversion to initializers.
Reviewed By: PeteSteinfeld
Differential Revision: https://reviews.llvm.org/D82137
Summary:
Fortran::evaluate::IsConstantExpr did not check that the numerator
was a constant expression. This patch fixes the issue.
Reviewers: DavidTruby, klausler, schweitz, PeteSteinfeld, jdoerfert, sscalpone
Reviewed By: klausler, PeteSteinfeld, sscalpone
Subscribers: llvm-commits
Tags: #llvm, #flang
Differential Revision: https://reviews.llvm.org/D81096
Summary
- Implemented C876, C877
- Fixed IsConstantExpr to check C879
- Fixed bugs in few test cases - data01.f90, block-data01.f90,
pre-fir-tree02.f90
- Modified implementation of C8106 to identify all automatic objects
and modified equivalence01.f90 to reflect the changes
Differential Revision: https://reviews.llvm.org/D78424
Summary:
Some Symbol-related functions used in Evaluate were moved to
Evaluate/tools.h. This includes changing some member functions that were
replaced by non-member functions `IsDummy`, `GetUsedModule`, and
`CountLenParameters`.
Some member functions were made inline in `Scope`, `Symbol`,
`ArraySpec`, and `DeclTypeSpec`. The definitions were preceded by a
comment explaining why they are inline.
`IsConstantShape` was expanded inline in `IsDescriptor` because it isn't
used anywhere else
After this change, at least when compiling with clang on macos,
`libFortranEvaluate.a` has no undefined symbols that are satisfied by
`libFortranSemantics.a`.
Reviewers: klausler, PeteSteinfeld, sscalpone, jdoerfert, DavidTruby
Reviewed By: PeteSteinfeld
Subscribers: llvm-commits
Tags: #flang, #llvm
Differential Revision: https://reviews.llvm.org/D80762
Summary:
Many of these were already implemented, and I just annotated the tests and/or
the code.
C752 was a simple check to verify that CONTIGUOUS components are arrays with
C754 proved to be virtually identical to C750 that I implemented previously.
This caused me to remove the distinction between specification expressions for
type parameters and bounds expressions that I'd previously created.
the POINTER attribute.
I also changed the error messages to specify that errors in specification
expressions could arise from either bad derived type components or type
parameters.
In cases where we detect a type param that was not declared, I created a symbol
marked as erroneous. That avoids subsequent semantic process for expressions
containing the symbol. This change caused me to adjust tests resolve33.f90 and
resolve34.f90. Also, I avoided putting out error messages for erroneous type
param symbols in `OkToAddComponent()` in resolve-names.cpp and in
`EvaluateParameters()`, type.cpp.
C756 checks that procedure components have the POINTER attribute.
Reviewers: tskeith, klausler, DavidTruby
Subscribers: llvm-commits
Tags: #llvm, #flang
Differential Revision: https://reviews.llvm.org/D79798
Summary: I updated the code that produces the message and the associated test.
Reviewers: sscalpone, DavidTruby, kiranchandramohan
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D79514
Summary: I updated the code that produces the message and the associated test.
Reviewers: sscalpone, DavidTruby
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D79514
Summary:
Most of these checks were already implemented, and I just added references to
them to the code and tests. Also, much of this code was already
reviewed in the old flang/f18 GitHub repository, but I didn't get to
merge it before we switched repositories.
I implemented the check for C747 to not allow coarray components in derived
types that are of type C_PTR, C_FUNPTR, or type TEAM_TYPE.
I implemented the check for C748 that requires a data component whose type has
a coarray ultimate component to be a nonpointer, nonallocatable scalar and not
be a coarray.
I implemented the check for C750 that adds additional restrictions to the
bounds expressions of a derived type component that's an array.
These bounds expressions are sepcification expressions as defined in
10.1.11. There was already code in lib/Evaluate/check-expression.cpp to
check semantics for specification expressions, but it did not check for
the extra requirements of C750.
C750 prohibits specification functions, the intrinsic functions
ALLOCATED, ASSOCIATED, EXTENDS_TYPE_OF, PRESENT, and SAME_TYPE_AS. It
also requires every specification inquiry reference to be a constant
expression, and requires that the value of the bound not depend on the
value of a variable.
To implement these additional checks, I added code to the intrinsic proc
table to get the intrinsic class of a procedure. I also added an
enumeration to distinguish between specification expressions for
derived type component bounds versus for type parameters. I then
changed the code to pass an enumeration value to
"CheckSpecificationExpr()" to indicate that the expression was a bounds
expression and used this value to determine whether to emit an error
message when violations of C750 are found.
I changed the implementation of IsPureProcedure() to handle statement
functions and changed some references in the code that tested for the
PURE attribute to call IsPureProcedure().
I also fixed some unrelated tests that got new errors when I implemented these
new checks.
Reviewers: tskeith, DavidTruby, sscalpone
Subscribers: jfb, llvm-commits
Tags: #llvm, #flang
Differential Revision: https://reviews.llvm.org/D79263
Summary:
Updates recent work on DATA statement semantic checking in
flang/lib/Semantics/check-data.{h,cpp} to use the compiler's
internal representation for typed expressions rather than working
on the raw parse tree. Saves the analyzed expressions for DATA
statement values as parse tree decorations because they'll soon be
needed in lowering. Corrects wording of some error messages.
Fixes a bug in constant expression checking: structure constructors
are not constant expressions if they set an allocatable component
to anything other than NULL.
Includes infrastructure changes to make this work, some renaming
to reflect the fact that the implied DO loop indices tracked by
expression analysis are not (just) from array constructors, remove
some dead code, and improve some comments.
Reviewers: tskeith, sscalpone, jdoerfert, DavidTruby, anchu-rajendran, schweitz
Reviewed By: tskeith, anchu-rajendran, schweitz
Subscribers: llvm-commits, flang-commits
Tags: #flang, #llvm
Differential Revision: https://reviews.llvm.org/D78834
Peter Klausler