In relation to the approval and merge of the
[PRIF](https://github.com/llvm/llvm-project/pull/76088) specification
about multi-image features in Flang, here is a first PR to add support
for the `-fcoarray` compilation flag and the initialization of the PRIF
environment.
Other PRs will follow for adding support of lowering to PRIF.
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).
Add a new `AutomapToTargetData` pass. This gathers the declare target
enter variables which have the `AUTOMAP` modifier. And adds
`omp.declare_target_enter/exit` mapping directives for `fir.allocmem`
and `fir.freemem` oeprations on the `AUTOMAP` enabled variables.
Automap Ref: OpenMP 6.0 section 7.9.7.
Interpret TRANSFER(SOURCE=BOZ literal, MOLD=integer or real scalar) as
if it had been a reference to the standard INT or REAL intrinsic
functions, for which a BOZ literal is an acceptable argument, with a
warning about non-conformance. It's a needless extension that has
somehow crept into some other compilers and real applications.
Adds a hint to the warning message to disable a warning and updates the
tests to expect this.
Also fixes a bug in the storage of canonical spelling of error flags so
that they are not used after free.
This just adds some convenience methods to feature control and rewrites
old code in terms of those methods. Also cleans up some names that I
just realize were overloads of another method.
This change allows the flang CLI to accept `-W[no-]<feature>` flags matching the clang syntax and enable and disable usage and language feature warnings.
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.
Nearly, but not all, other compilers have a blanket prohibition against
the use of an INTENT(OUT) dummy argument in a specification expression.
Some compilers, however, permit an INTENT(OUT) dummy argument to appear
in a specification expression in a BLOCK construct or inner procedure
via host association.
The argument some have put forth to accept this usage comes from a
reading of 10.1.11 (specification expressions) in Fortran 2023 that, if
followed consistently, would also require host-associated OPTIONAL dummy
argument to be allowed. That would be dangerous for reasons that should
be obvious.
However, I can agree that a non-OPTIONAL dummy argument can't be assumed
to remain undefined on entry to a BLOCK construct or inner procedure, so
we can accept host-associated INTENT(OUT) in specification expressions
with a portability warning.
A function or subroutine can allow an object of the same name to appear
in its scope, so long as the name is not used. This is similar to the
case of a name being imported from multiple distinct modules, and
implemented by the same representation.
It's not clear whether this is conforming behavior or a common
extension.
The HAS_DEVICE_ADDR indicates that the object(s) listed exists at an
address that is a valid device address. Specifically,
`has_device_addr(x)` means that (in C/C++ terms) `&x` is a device
address.
When entering a target region, `x` does not need to be allocated on the
device, or have its contents copied over (in the absence of additional
mapping clauses). Passing its address verbatim to the region for use is
sufficient, and is the intended goal of the clause.
Some Fortran objects use descriptors in their in-memory representation.
If `x` had a descriptor, both the descriptor and the contents of `x`
would be located in the device memory. However, the descriptors are
managed by the compiler, and can be regenerated at various points as
needed. The address of the effective descriptor may change, hence it's
not safe to pass the address of the descriptor to the target region.
Instead, the descriptor itself is always copied, but for objects like
`x`, no further mapping takes place (as this keeps the storage pointer
in the descriptor unchanged).
---------
Co-authored-by: Sergio Afonso <safonsof@amd.com>
…dummy
We presently allow a NULL() actual argument to associate with a
non-optional dummy allocatable argument only under INTENT(IN). This is
too strict, as it precludes the case of a dummy argument with default
intent. Continue to require that the actual argument be definable under
INTENT(OUT) and INTENT(IN OUT), and (contra XLF) interpret NULL() as
being an expression, not a definable variable, even when it is given an
allocatable MOLD.
Fixes https://github.com/llvm/llvm-project/issues/115984.
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.
Introduce a new `MLIR_LIBS` argument to `add_flang_library`, that uses
`mlir_target_link_libraries` to link the MLIR dylib alterantively to the
component libraries. Use it, along with a few inline
`mlir_target_link_libraries` in tools, to support linking Flang to MLIR
dylib rather than the static libraries.
With these changes, the vast majority of Flang can be linked
dynamically. The only parts still using static libraries are these
requiring MLIR test libraries, that are not included in the dylib.
The behavior is not entirely consistent with that of clang for the
moment since detailed timing information on the LLVM IR optimization and
code generation passes is not provided. The -ftime-report= option is
also not enabled since that is only relevant for information about the
LLVM IR passes. However, some code to handle that option has been
included, to make it easier to support the option when the issues
blocking it are resolved. A FortranSupport library has been created that
is intended to mirror the LLVM and MLIR support libraries.
Based on @tarunprabhu's PR
https://github.com/llvm/llvm-project/pull/107270 with minor changes
addressing latest review feedback. He's busy and we'd like to get this
support in ASAP.
Co-authored-by: Tarun Prabhu <tarun.prabhu@gmail.com>
