8 Commits

Author SHA1 Message Date
Peter Klausler
4fed595997
[flang] Correct semantic representation & handling of RANK(*) (#66234)
A RANK(*) case in a SELECT RANK construct selects the case of an
assumed-rank dummy argument whose effective actual argument is an
assumed-size array. In this case, the attributes of the selector are
those of a rank-1 assumed-size array, and the selector cannot be
allocatable or a pointer.

Ensure that the representation of a SELECT RANK construct's per-case
AssocEntityDetails can distinguish RANK(n), RANK(*), and RANK DEFAULT,
and clean up various code sites and tests where the distinctions matter.
2023-09-13 16:13:31 -07:00
Peter Klausler
031b4e5e79
[flang] Support SELECT RANK on allocatables & pointers
Unlike other executable constructs with associating selectors, the
selector of a SELECT RANK construct can have the ALLOCATABLE or POINTER
attribute, and will work as an allocatable or object pointer within
each rank case, so long as there is no RANK(*) case.

Getting this right exposed a correctness risk with the popular
predicate IsAllocatableOrPointer() -- it will be true for procedure
pointers as well as object pointers, and in many contexts, a procedure
pointer should not be acceptable.  So this patch adds the new predicate
IsAllocatableOrObjectPointer(), and updates some call sites of the original
function to use the new one.

Differential Revision: https://reviews.llvm.org/D159043
2023-08-29 14:56:15 -07:00
Peter Klausler
cd03e96f00 [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().
2022-04-16 16:00:48 -07:00
Peter Klausler
ef141aec3c [flang] Improve appearance of message attachments
Error messages can have a list of attachments; these are used to point
to related source locations, supply additional information, and to
encapsulate error messages that were *not* emitted in a given context
to explain why a warning was justified.

This patch adds a message severity ("Because") for that last case,
and extends to AttachTo() API to provide a means for overriding
the severity of an attached message.

Some existing message attachments had their severities adjusted,
now that we're printing them.  And operator==() for Message was
cleaned up while debugging after I noticed that it was recursively
O(N**2) and subject to returning a false positive.

Differential Revision: https://reviews.llvm.org/D123710
2022-04-14 07:34:50 -07:00
Andrzej Warzynski
4ca111d4cb 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)
2022-03-28 10:46:47 +00:00
Peter Klausler
2ab9990c9e [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
2022-03-25 13:15:20 -07:00
peter klausler
9245f35580 [flang] Validate SIZE(x,DIM=n) dimension for assumed-size array x
Catch invalid attempts to extract the unknowable extent of the last
dimension of an assumed-size array dummy argument, and clean up
problems with assumed-rank arguments in similar circumstances
exposed by testing the fix.

Differential Revision: https://reviews.llvm.org/D109918
2021-09-17 10:14:18 -07:00
sameeran joshi
332e6aea37 [flang]Semantics for SELECT RANK.
Summary:
    Initially on github I worked on semantic checks.Then I tried some compile-time
    test of the rank value, they were failing as there were no symbols
    generated for them inside SELECT RANK's scope.So I went further to
    add new symbol in each scope, also added the respective 'rank: '
    field for a symbol when we dump the symboltable. I added a field to
    keep track of the rank in AssocEntityDetails class.This caused shape
    analysis framework to become inconsistent. So shape analysis framework
    was updated to handle this new representation.

	 *   I added more tests for above changes.

	 *   On phabricator I addressed some minor changes.

	 *   Lastly I worked on review comments.

    Reviewers: klausler,sscalpone,DavidTruby,kiranchandramohan,tskeith,anchu-rajendran,kiranktp

    Reviewed By:klausler, DavidTruby, tskeith

    Subscribers:#flang-commits, #llvm-commits

    Tags: #flang, #llvm

    Differential Revision: https://reviews.llvm.org/D78623
2020-05-08 08:52:31 +05:30