[flang] Allow restricted specific intrinsic functions as implicitly-interfaced procedure pointer targets

The predicate "CanBeCalledViaImplicitInterface()" was returning false for
restricted specific

[flang] Allow restricted specific intrinsic functions as implicitly-interfaced procedure pointer targets

The predicate "CanBeCalledViaImplicitInterface()" was returning false for
restricted specific intrinsic functions (e.g., SIN) because their procedure
characteristics have the elemental attribute; this leads to a bogus semantic
error when one attempts to use them as proc-targets in procedure pointer
assignment statements when the left-hand side of the assignment is a procedure
pointer with an implicit interface. However, these restricted specific intrinsic
functions have always been allowed as special cases for such usage -- it is
as if they are elemental when it is necessary for them to be so, but not
when it's a problem.

Differential Revision: https://reviews.llvm.org/D130386

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[flang] Refine semantic checks for procedure pointer assignment

Some procedure pointers and EXTERNAL procedures have neither
explicit interfaces nor result types; these procedures are obviously
not

[flang] Refine semantic checks for procedure pointer assignment

Some procedure pointers and EXTERNAL procedures have neither
explicit interfaces nor result types; these procedures are obviously
not known to be functions, but they could be, so semantics must not
assume that they are necessarily subroutines. Refine the procedure
pointer / dummy procedure compatibility check to handle these more
ambiguous cases and not elicit inappropriate error messages.

Differential Revision: https://reviews.llvm.org/D129674

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[flang] Add & use a better visit() (take 2)

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().

[flang] Add & use a better visit() (take 2)

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().

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Revert "[flang] Add & use a better visit()"

This reverts commit 2ab9990c9eb79682a4d4b183dfbc7612d3e55328. It has
caused multiple build failures:
* https://lab.llvm.org/buildbot/#/builders/177/build

Revert "[flang] Add & use a better visit()"

This reverts commit 2ab9990c9eb79682a4d4b183dfbc7612d3e55328. It has
caused multiple build failures:
* https://lab.llvm.org/buildbot/#/builders/177/builds/4346
* https://lab.llvm.org/buildbot/#/builders/180/builds/3803
* https://lab.llvm.org/buildbot/#/builders/175/builds/10419
* https://lab.llvm.org/buildbot/#/builders/191/builds/4318
* https://lab.llvm.org/buildbot/#/builders/173/builds/4274
* https://lab.llvm.org/buildbot/#/builders/181/builds/4297

All these bots failed with a time-out:
```
command timed out: 1200 seconds without output running [b'ninja', b'-j', b'32'], attempting to kill
```
I'm guessing that that's due to template instantiations failing at some
point (https://reviews.llvm.org/D122441 introduced a custom
implementation of std::visit). Everything seems fine when either:
* building on X86 with GCC or Clang (tested with GCC 9.3 and Clang 12)
* building on AArch64 with GCC (tested with GCC 11)

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[flang] Add & use a better visit()

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

[flang] Add & use a better visit()

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

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[flang] Accept pointer assignment w/ remapping to function result

When a pointer assignment with bounds remapping has a function
reference as its right-hand side, don't check for array conformance.

[flang] Accept pointer assignment w/ remapping to function result

When a pointer assignment with bounds remapping has a function
reference as its right-hand side, don't check for array conformance.

Differential Revision: https://reviews.llvm.org/D119845

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[Flang][OpenMP] Use the ultimate symbol in a call to the IsPointer function

The IsPointer check currently fails for host-associated symbols in OpenMP
regions. This causes some failures in semantic c

[Flang][OpenMP] Use the ultimate symbol in a call to the IsPointer function

The IsPointer check currently fails for host-associated symbols in OpenMP
regions. This causes some failures in semantic checks for pointer association
in an OpenMP region. Fix is to use the ultimate symbol in the call to the
IsPointer function in CheckPointerAssignment function in
lib/Semantics/pointer-assignment.cpp.

Reviewed By: klausler, peixin

Differential Revision: https://reviews.llvm.org/D112876

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[flang] More checking of NULL pointer actual arguments

Catch additional missing error cases for typed and untyped
NULL actual arguments to non-intrinsic procedures in cases
of explicit and implicit

[flang] More checking of NULL pointer actual arguments

Catch additional missing error cases for typed and untyped
NULL actual arguments to non-intrinsic procedures in cases
of explicit and implicit interfaces.

Differential Revision: https://reviews.llvm.org/D110003

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[flang] Complain about more cases of calls to insufficiently defined procedures

When a function is called in a specification expression, it must be
sufficiently defined, and cannot be a recursive ca

[flang] Complain about more cases of calls to insufficiently defined procedures

When a function is called in a specification expression, it must be
sufficiently defined, and cannot be a recursive call (10.1.11(5)).
The best fix for this is to change the contract for the procedure
characterization infrastructure to catch and report such errors,
and to guarantee that it does emit errors on failed characterizations.
Some call sites were adjusted to avoid cascades.

Differential Revision: https://reviews.llvm.org/D104330

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[flang] CheckConformance: tristate-ify result

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 dist

[flang] CheckConformance: tristate-ify result

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

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[flang] Fix false error message for "ptr => func()" array conformance

Pointers must have deferred shapes, so CheckConformance must be
extended to allow for them.

Differential Revision: https://revi

[flang] Fix false error message for "ptr => func()" array conformance

Pointers must have deferred shapes, so CheckConformance must be
extended to allow for them.

Differential Revision: https://reviews.llvm.org/D93320

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[flang] Improve initializer semantics, esp. for component default values

This patch plugs many holes in static initializer semantics, improves error
messages for default initial values and other com

[flang] Improve initializer semantics, esp. for component default values

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

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[flang] Failed call to CHECK() for call to ASSOCIATED(NULL())

Calling "ASSOCATED(NULL()) was causing an internal check of the compiler to
fail.

I fixed this by changing the entry for "ASSOCIATED" i

[flang] Failed call to CHECK() for call to ASSOCIATED(NULL())

Calling "ASSOCATED(NULL()) was causing an internal check of the compiler to
fail.

I fixed this by changing the entry for "ASSOCIATED" in the intrinsics table to
accept "AnyPointer" which contains a new "KindCode" of "pointerType". I also
changed the function "FromActual()" to return a typeless intrinsic when called
on a pointer, which duplicates its behavior for BOZ literals. This required
changing the analysis of procedure arguments. While testing processing for
procedure arguments, I found another bad call to `CHECK()` which I fixed.

I made several other changes:
-- I implemented constant folding for ASSOCIATED().
-- I fixed handling of NULL() in relational operations.
-- I implemented semantic analysis for ASSOCIATED().
-- I noticed that the semantics for ASSOCIATED() are similar to those for
pointer assignment. So I extracted the code that pointer assignment uses
for procedure pointer compatibility to a place where it could be used by
the semantic analysis for ASSOCIATED().
-- I couldn't figure out how to make the general semantic analysis for
procedure arguments work with ASSOCIATED()'s second argument, which can
be either a pointer or a target. So I stopped using normal semantic
analysis for arguments for ASSOCIATED().
-- I added tests for all of this.

Differential Revision: https://reviews.llvm.org/D88313

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[flang] Semantic analysis for FINAL subroutines

Represent FINAL subroutines in the symbol table entries of
derived types. Enforce constraints. Update tests that have
inadvertent violations or modi

[flang] Semantic analysis for FINAL subroutines

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

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[flang] Check shape conformance on initializers

Specifically, ensure that initializers conform with their objects
according to 8.2 para 4.

Differential Revision: https://reviews.llvm.org/D86886

[flang][NFC] Reformat files with current clang-format

Differential Revision: https://reviews.llvm.org/D85489

[flang] DATA stmt processing (part 3/4): Remaining prep work

Rolls up small changes across the frontend to prepare for the large
forthcoming patch (part 4/4) that completes DATA statement processing

[flang] DATA stmt processing (part 3/4): Remaining prep work

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

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[flang] Merge flang-compiler/f18

This is the initial merge of flang-compiler, which is done in this way
principally to preserve the history and git-blame, without generating a large
number of commit

[flang] Merge flang-compiler/f18

This is the initial merge of flang-compiler, which is done in this way
principally to preserve the history and git-blame, without generating a large
number of commits on the first-parent history of LLVM.

If you don't care about the flang history during a bisect remember that you can
supply paths to git-bisect, e.g. `git bisect start clang llvm`.

The history of f18 was rewritten to:

* Put the code under /flang/.
* Linearize the history.
* Rewrite commit messages so that issue and PR numbers point to the old repository.

Credit to Peter Waller for writing the flatten and merge script.

Updates: flang-compiler/f18#876 (submission into llvm-project)
Mailing-list: http://lists.llvm.org/pipermail/llvm-dev/2020-January/137989.html ([llvm-dev] Flang landing in the monorepo - next Monday!)
Mailing-list: http://lists.llvm.org/pipermail/llvm-dev/2019-December/137661.html ([llvm-dev] Flang landing in the monorepo)

Co-authored-by: Peter Waller <peter.waller@arm.com>

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[flang] Reformat with latest clang-format and .clang-format

Original-commit: flang-compiler/f18@9fe84f45d7fd685051004678d6b5775dcc4c6f8f
Reviewed-on: https://github.com/flang-compiler/f18/pull/1094

[flang] [LLVMify F18] Replace the use std::ostream with LLVM streams llvm::ostream

This patch replaces the occurrence of std::ostream by llvm::raw_ostream.
In LLVM Coding Standards[1] "All new code

[flang] [LLVMify F18] Replace the use std::ostream with LLVM streams llvm::ostream

This patch replaces the occurrence of std::ostream by llvm::raw_ostream.
In LLVM Coding Standards[1] "All new code should use raw_ostream
instead of ostream".[1]

As a consequence, this patch also replaces the use of:
std::stringstream by llvm::raw_string_ostream or llvm::raw_ostream*
std::ofstream by llvm::raw_fd_ostream
std::endl by '\n' and flush()[2]
std::cout by llvm::outs() and
std::cerr by llvm::errs()

It also replaces std::strerro by llvm::sys::StrError** , but NOT in Fortran
runtime libraries

*std::stringstream were replaced by llvm::raw_ostream in all methods that
used std::stringstream as a parameter. Moreover, it removes the pointers to
these streams.

[1]https://llvm.org/docs/CodingStandards.html
[2]https://releases.llvm.org/2.5/docs/CodingStandards.html#ll_avoidendl

Signed-off-by: Caroline Concatto <caroline.concatto@arm.com>

Running clang-format-7

Signed-off-by: Caroline Concatto <caroline.concatto@arm.com>

Removing residue of ostream library

Signed-off-by: Caroline Concatto <caroline.concatto@arm.com>

Original-commit: flang-compiler/f18@a3507d44b8911e6024033aa583c1dc54e0eb89fd
Reviewed-on: https://github.com/flang-compiler/f18/pull/1047

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[flang] [LLVMify F18] Compiler module folders should have capitalised names (flang-compiler/f18#980)

This patch renames the modules in f18 to use a capital letter in the
module name

Signed-off-b

[flang] [LLVMify F18] Compiler module folders should have capitalised names (flang-compiler/f18#980)

This patch renames the modules in f18 to use a capital letter in the
module name

Signed-off-by: Caroline Concatto <caroline.concatto@arm.com>

Original-commit: flang-compiler/f18@d2eb7a1c443d1539ef12b6f027074a0eb15b1ea0
Reviewed-on: https://github.com/flang-compiler/f18/pull/980

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