When a REAL or COMPLEX literal appears without an explicit kind suffix
or a kind-determining exponent letter, and the conversion of that
literal from decimal to binary is inexact, emit a warning if that
constant is later implicitly widened to a more precise kind, since it
will have a different value than was probably intended.
Values that convert exactly from decimal to default real, e.g. 1.0 and
0.125, do not elicit this warning.
There are many contexts in which Fortran implicitly converts constants.
This patch covers name constant values, variable and component
initialization, constants in expressions, structure constructor
components, and array constructors.
For example, "real(8) :: tenth = 0.1" is a common Fortran bug that's
hard to find, and is one that often trips up even experienced Fortran
programmers. Unlike C and C++, the literal constant 0.1 is *not* double
precision by default, and it does not have the same value as 0.1d0 or
0.1_8 do when it is converted from decimal to real(4) and then to
real(8).
Fortran's intrinsic numeric and relational operators can be overridden
with explicit interfaces so long as one or more of the dummy arguments
have the DEVICE attribute. Semantics already allows this without
complaint, but fails to replace the operations with the defined specific
procedure calls when analyzing expressions.
When a type-bound generic ASSIGNMENT(=) procedure is ambiguous for a
particular reference, say so, rather than claiming that no specific
procedure matched the types and ranks of the LHS and RHS.
Fixes https://github.com/llvm/llvm-project/issues/148675.
When blank tokens arise from macro replacement in token sequences with
token pasting (##), the preprocessor is producing some bogus tokens
(e.g., "name(") that can lead to subtle bugs later when macro names are
not recognized as such.
The fix is to not paste tokens together when the result would not be a
valid Fortran or C token in the preprocessing context.
When a generic ASSIGNMENT(=) has elemental and non-elemental specific
procedures that match the actual arguments, the non-elemental procedure
must take precedence. We get this right for generics defined with
interface blocks, but the type-bound case fails if the non-elemental
specific takes a non-default PASS argument.
Fixes https://github.com/llvm/llvm-project/issues/141807.
When a TYPE(*) dummy argument is erroneously used as a component value
in a structure constructor, semantics crashes if the structure
constructor had been initially parsed as a potential function reference.
Clean out stale typed expressions when reanalyzing the reconstructed
parse subtree to ensure that errors are caught the next time around.
For more compatible legacy behavior on old tests, extend Hollerith
actual arguments on the right with trailing blanks out to a multiple of
8 bytes. Fixes Fujitsu test 0343_0069.
F'2023 allows the right-hand side of an assignment to an integer or real
scalar to be a BOZ literal constant; this has already been supported in
some compilers. The type of the left-hand side variable is used to
convert the value of the BOZ.
An assignment to a whole polymorphic object in a PURE subprogram that is
implemented by means of a defined assignment procedure shouldn't be
subjected to the same definability checks as it would be for an
intrinsic assignment (which would also require it to be allocatable).
Fixes https://github.com/llvm/llvm-project/issues/139129.
Fortran 2023 constraint C7108 prohibits the use of a structure
constructor in a way that is ambiguous with a generic function reference
(intrinsic or user-defined). Sadly, no Fortran compiler implements this
constraint, and the common portable interpretation seems to be the
generic resolution, not the structure constructor.
Restructure the processing of structure constructors in expression
analysis so that it can be driven both from the parse tree as well as
from generic resolution, and then use it to detect ambigous structure
constructor / generic function cases, so that a portability warning can
be issued. And document this as a new intentional violation of the
standard in Extensions.md.
Fixes https://github.com/llvm/llvm-project/issues/138807.
Bring the typed expression representation of a coindexed reference up to
F'2023, which removed some restrictions that had allowed the current
representation to suffice for older revisions of the language. This new
representation is somewhat more simple -- it uses a DataRef as its base,
so any subscripts in a part-ref can be represented as an ArrayRef there.
Update the code that creates the CoarrayRef, and add more checking to
it, as well as actually capturing any STAT=, TEAM=, & TEAM_NUMBER=
specifiers that might appear. Enforce the constraint that the part-ref
must have subscripts if it is an array. (And update a pile of
copied-and-pasted test code that lacked such subscripts.)
Fortran::runtime::Descriptor::BytesFor() only works for Fortran
intrinsic types for which a C++ type counterpart exists, so it crashes
on some types that are legitimate Fortran types like REAL(2). Move some
logic from Evaluate into a new header in flang/Common, then use it to
avoid this needless dependence on C++.
Whole assumed-size arrays are generally not allowed outside specific
contexts, where expression analysis notes that they can appear. But
contexts can nest, and in the case of an actual argument that turns out
to be an array constructor, the permission to use a whole assumed-size
array must be rescinded.
Fixes https://github.com/llvm/llvm-project/issues/131909.
When reinterpreting an ambiguously parsed function reference as a
structure constructor, use the original symbol of the type in the
representation of the derived type spec of the structure constructor,
not its ultimate resolution. The distinction turns out to matter when
generating module files containing derived type constants as
initializers when the derived types' names have undergone USE
association renaming.
Fixes https://github.com/llvm/llvm-project/issues/131579.
These are constraints that preclude the need to obtain type information
from descriptors on other images, essentially. When designating a
polymorphic component, its base may not be coindexed; nor shall a
coindexed designator have a type with a polymorphic potential subobject
component.
F'2023 10.2.1.2 paragraph 2 imposes some requirements on the left-hand
sides of assignments when they have coindices, and one was not checked
while another was inaccurately checked. In short, intrinsic assignment
to a coindexed object can't change its type, and neither can it affect
allocatable components.
Refine handling of NULL(...) in semantics to properly distinguish
NULL(), NULL(objectPointer), NULL(procPointer), and NULL(allocatable)
from each other in relevant contexts.
Add IsNullAllocatable() and IsNullPointerOrAllocatable() utility
functions. IsNullAllocatable() is true only for NULL(allocatable); it is
false for a bare NULL(), which can be detected independently with
IsBareNullPointer().
IsNullPointer() now returns false for NULL(allocatable).
ALLOCATED(NULL(allocatable)) now works, and folds to .FALSE.
These utilities were modified to accept const pointer arguments rather
than const references; I usually prefer this style when the result
should clearly be false for a null argument (in the C sense), and it
helped me find all of their use sites in the code.
The definition of an array constructor doesn't preclude the use of
[character(:)::] or [character(*)::] directly, but there is language
elsewhere in the standard that restricts their use to specific contexts,
neither of which include explicitly typed array constructors.
Fixes https://github.com/llvm/llvm-project/issues/128755.
A few bits of semantic checking need a variant of the
ResolveAssociations utility function that stops when hitting a construct
entity for a type or class guard. This is necessary for cases like the
bug below where the analysis is concerned with the type of the name in
context, rather than its shape or storage or whatever. So add a flag to
ResolveAssociations and GetAssociationRoot to make this happen, and use
it at the appropriate call sites.
Fixes https://github.com/llvm/llvm-project/issues/128608.
Move non-common files from FortranCommon to FortranSupport (analogous to
LLVMSupport) such that
* declarations and definitions that are only used by the Flang compiler,
but not by the runtime, are moved to FortranSupport
* declarations and definitions that are used by both ("common"), the
compiler and the runtime, remain in FortranCommon
* generic STL-like/ADT/utility classes and algorithms remain in
FortranCommon
This allows a for cleaner separation between compiler and runtime
components, which are compiled differently. For instance, runtime
sources must not use STL's `<optional>` which causes problems with CUDA
support. Instead, the surrogate header `flang/Common/optional.h` must be
used. This PR fixes this for `fast-int-sel.h`.
Declarations in include/Runtime are also used by both, but are
header-only. `ISO_Fortran_binding_wrapper.h`, a header used by compiler
and runtime, is also moved into FortranCommon.
Currently the use of REAL/COMPLEX(KIND=10) as a type or literal constant
suffix elicits an optional warning message only. This leads to compiler
internal errors during lowering when these types appear in code being
compiled to non-x86_64 targets. For better error messaging, make the use
of these types a hard error in semantics instead when they are not
supported by the target architecture.
A designator without cosubscripts can have subscripts, component
references, substrings, &c. and still have corank. The current
IsCoarray() predicate only seems to work for whole variable/component
references. This was breaking some cases of THIS_IMAGE().
A recent patch added better compatibility checking for actual procedure
arguments, but it has led to a few failures in the Fujitsu Fortran test
suite in cases of NULL() actual arguments being associated with dummy
procedure pointers. As is the case with dummy data pointers, these must
always be accepted.
Fixes Fujitsu Fortran test cases 0249_0023 through 0028 and 0387_0047.
Implement the UNSIGNED extension type and operations under control of a
language feature flag (-funsigned).
This is nearly identical to the UNSIGNED feature that has been available
in Sun Fortran for years, and now implemented in GNU Fortran for
gfortran 15, and proposed for ISO standardization in J3/24-116.txt.
See the new documentation for details; but in short, this is C's
unsigned type, with guaranteed modular arithmetic for +, -, and *, and
the related transformational intrinsic functions SUM & al.
…ility
We generally allow any legal procedure pointer target as an actual
argument for association with a dummy procedure, since many actual
procedures are underspecified EXTERNALs. But for proper generic
resolution, it is necessary to disallow incompatible functions with
explicit result types.
Fixes https://github.com/llvm/llvm-project/issues/119151.
An empty array shouldn't be subscripted, but sometimes they are in
zero-trip loops in real applications. So change a recently added error
message to a warning (off by default).
(This is a big patch, but it's nearly an NFC. No test results have
changed and all Fortran tests in the LLVM test suites work as expected.)
Allow a parser::Message for a warning to be marked with the
common::LanguageFeature or common::UsageWarning that controls it. This
will allow a later patch to add hooks whereby a driver will be able to
decorate warning messages with the names of its options that enable each
particular warning, and to add hooks whereby a driver can map those
enumerators by name to command-line options that enable/disable the
language feature and enable/disable the messages.
The default settings in the constructor for LanguageFeatureControl were
moved from its header file into its C++ source file.
Hooks for a driver to use to map the name of a feature or warning to its
enumerator were also added.
To simplify the tagging of warnings with their corresponding language
feature or usage warning, to ensure that they are properly controlled by
ShouldWarn(), and to ensure that warnings never issue at code sites in
module files, two new Warn() member function templates were added to
SemanticsContext and other contextual frameworks. Warn() can't be used
before source locations can be mapped to scopes, but the bulk of
existing code blocks testing ShouldWarn() and FindModuleFile() before
calling Say() were convertible into calls to Warn(). The ones that were
not convertible were extended with explicit calls to
Message::set_languageFeature() and set_usageWarning().
GETUID and GETGID are non-standard intrinsics supported by a number of
other Fortran compilers. On supported platforms these intrinsics simply
call the POSIX getuid() and getgid() functions and return the result.
The only platform we support that does not have these is Windows.
Windows does not have the same concept of UIDs and GIDs, so on Windows
we issue a warning indicating this and return 1 from both functions.
Co-authored-by: Yi Wu <yi.wu2@arm.com>
GETUID and GETGID are non-standard intrinsics supported by a number of
other Fortran compilers. On supported platforms these intrinsics simply
call the POSIX getuid() and getgid() functions and return the result.
The only platform we support that does not have these is Windows.
Windows does not have the same concept of UIDs and GIDs, so on Windows
we issue a warning indicating this and return 1 from both functions.
Co-authored-by: Yi Wu <yi.wu2@arm.com>
---------
Co-authored-by: Yi Wu <yi.wu2@arm.com>
As specified in the docs,
1) raw_string_ostream is always unbuffered and
2) the underlying buffer may be used directly
( 65b13610a5226b84889b923bae884ba395ad084d for further reference )
Avoid unneeded calls to raw_string_ostream::str(), to avoid excess indirection.
An array that has one or more empty dimensions cannot have subscripts
unless there's a possibility that they constitute an empty array
section.
We previously only checked that constant subscripts are in bounds.
Use associated procedure pointers were eliciting bogus errors from
semantics if their modules also contained generic procedure interfaces
of the same name. (The compiler handles this case correctly when the
specific procedure of the same name is not a pointer.)
With this fix, the test case in
https://github.com/llvm/llvm-project/issues/107784
no longer experiences semantic errors; however, it now crashes
unexpectedly in lowering.
A defined assignment generic interface for a given LHS/RHS type & rank
combination may have a specific procedure with LHS dummy argument that
is neither allocatable nor pointer, or specific procedure(s) whose LHS
dummy arguments are allocatable or pointer. It is possible to have two
specific procedures if one's LHS dummy argument is allocatable and the
other's is pointer.
However, the runtime doesn't work with LHS dummy arguments that are
allocatable, and will crash with a mysterious "invalid descriptor" error
message.
Extend the list of special bindings to include
ScalarAllocatableAssignment and ScalarPointerAssignment, use them when
appropriate in the runtime type information tables, and handle them in
Assign() in the runtime support library.
When a module file has been compiled with CUDA enabled, don't emit
spurious errors about non-interoperable types when that module is read
by a USE statement in a later non-CUDA compilation.
Most warnings should be silenced when processing the content of a module
file, since the warning should have also appeared when the module file
was generated. The case of an intrinsic type kind not being supported
for a target wasn't being suppressed; fix.
Fixes https://github.com/llvm/llvm-project/issues/107337.
When the implementation of one SMP apparently references another in what
might be a specification expression, semantics may need to resolve it as
a forward reference, and to allow for the replacement of a
SubprogramNameDetails place-holding symbol with the final
SubprogramDetails symbol. Otherwise, as in the bug report below,
confusing error messages may result.
(The reference in question isn't really in the specification part of a
subprogram, but due to the syntactic ambiguity between the array element
assignment statement and a statement function definition, it appears to
be so at the time that the reference is processed.)
I needed to make DumpSymbols() available via SemanticsContext to analyze
this bug, and left that new API in place to make things easier next
time.
Fixes https://github.com/llvm/llvm-project/issues/106705.
…uctors
A non-conforming extension to Fortran present in a couple other
compilers is allowing a anonymous component in a structure constructor
to initialize a parent (or greater ancestor) component. This was working
in this compiler only for direct parents, and only when the type was not
use-associated.
Fixes https://github.com/llvm/llvm-project/issues/102557.
The check for a structure constructor to a forward-referenced derived
type wasn't tripping for constructors in the type definition itself. Set
the forward reference flag unconditionally at the beginning of name
resolution for the type definition.
Derived type assignment checking needs to account for the possibility of
derived assignment. The implementation was checking compile-time
conformance errors only on the path for assignments of intrinsic types.
Add a static array conformance check in the derived type flow once it
has been established that no defined assignment exists.
Fixes https://github.com/llvm/llvm-project/issues/98981.
Pull request https://github.com/llvm/llvm-project/pull/97337 was
reverted by https://github.com/llvm/llvm-project/pull/98612 due
to two failing tests in llvm-test-suite -- which I ran, as always,
but must have bungled or misinterpreted (mea culpa).
The failing tests were llvm-test-suite/Fortran/gfortran/regression/
char_length_{20,21}.f90. They have array constructors with
explicit character types whose dynamic length values are negative
at runtime, which must be interpreted as zero.
This patch extends the original to cover those cases.
