[flang-dev] Flang Biweekly Sync - Notes from September 4th, 2019 call
Gary Klimowicz via flang-dev
flang-dev at lists.llvm.org
Fri Sep 6 13:07:21 PDT 2019
Flang team,
Here are the notes from the September 4th, 2019 Flang biweekly call. Updates are in bold.
Please be sure to let us know if you have any questions and agenda topics for the next call.
The next Flang biweekly call will be Wednesday, September 18th, 2019 at 8:30 AM Pacific Time.
The next Flang Technical Community call is scheduled for Monday, September 9th, 8:30 AM Pacific Time. The topic will be module files.
Thank you.
Gary Klimowicz
Agenda
* SC 2019 – BoF for LLVM has been accepted
* LLVM Developer Meeting news
* MLIR for HPC Workshop news (at LCPC 2019)
* Flang Community Technical Call – Recap and next topic: DWARF?; moved to Mondays
* F18 development update
* Flang development update
* OpenMP update form Johannes Doerfert
Highlights
* Supercomputing 2019
* Hal’s LLVM BoF session at SC 2019<https://sc19.supercomputing.org/program/birds-of-a-feather/> was approved. No details yet about the schedule.
* LLVM Developer Meeting 2019
* The LLVM Dev Meeting is October 22-23 at the San Jose Convention Center; details can be found here<https://llvm.org/devmtg/2019-10/>.
* Eric Schweitz’s talk, An MLIR Dialect for High-Level Optimization of Fortran<https://llvm.org/devmtg/2019-10/talk-abstracts.html#tech19>, was accepted.
* MLIR for HPC Workshop 2019
* The MLIR for HPC workshop<http://www.cs.utah.edu/~mhall/mlir4hpc/> will be held October 21st in conjunction with the 32nd Workshop on Languages and Compilers for Parallel Computing<https://lcpc19.cc.gatech.edu/> October 22-24 at Georgia tech.
* Flang Community Technical Biweekly Call
* Hal Finkel is hosting this call on Bluejeans<https://bluejeans.com/625064848>, Mondays 8:30 Pacific Time, on the weeks alternating with this call. The notes for all these calls can be found in Google Docs here<https://docs.google.com/document/d/1Z2U5UAtJ-Dag5wlMaLaW1KRmNgENNAYynJqLW2j2AZQ/>. Note the new day.
* On the August 18th call, we discussed array descriptors; some people were missing on the call, so this may come up again.
* The next call is scheduled for Monday, September 9th, 8:30 AM PDT. The scheduled agenda topic is module files.
* Hal’s Doodle poll for changing the time of this call has concluded: https://doodle.com/poll/66m8mvavg7ag2t49. The new time is Monday, 8:30 AM Pacific time.
* F18 as an LLVM project
* The LLVM-hosted flang-dev mailing list has been set up. Subscribe at https://lists.llvm.org/cgi-bin/mailman/listinfo/flang-dev.
* We will continue to support the original flang-dev at lists.flang-compiler.org<mailto:flang-dev at lists.flang-compiler.org> and flang-sync at lists.flang-compiler.org<mailto:flang-sync at lists.flang-compiler.org> and through August 2019. Further emails will be sent only to the LLVM lists.
* Plan is still to upload documentation for F18 before the code, to help establish the project goals and design strategy before uploading the code. This should help establish context for the project. Steve has email to the administrators to get the initial phabricator top-level directory created.
* NVIDIA is still blocked on adding flang to the LLVM repo, but we are continuing to work with the LLVM admins; Hal is lending his support as well.
* F18 update
* Fixed issues in module file generation, array references, intrinsic calls, intrinsic folding.
* Implemented special handling for VOLATILE and ASYNCHRONOUS attributes.
* Finished conversion of floating-point binary<->decimal templates for use at compile time and run time.
* Worked on user procedure call protocol requirements and design.
* More work on DO loop semantics and constraint checking, including CYCLE statements. Additional semantic checks added.
* More work on OpenMP directive parsing and semantic checks, including Declare directives, block constructs, standalone directives, sections, atomic and critical constructs. Working through tests including SOLLVE.
* The driver “flang” turns on semantic processing by default. This will make it easier for people to check existing codes against f18 and expanding the test suite in f18.
* Craig Rasmussen reports that he has switch to using f18 for the Rose front-end. There’s more work to do, but he reported significant progress here.
* Flang Dev news and updates
* More bug fixes sent to Flang.
* Improved build support for Windows and Mac coming.
* Expecting CLA from Microsoft for contributing.
* Work continues on the BLOCK construct.
* Discussing turning more day-to-day responsibilities over to the community.
* Arm are now committers for flang-compiler/flang-driver.
Where we can use your help
* Subscribe to the new LLVM Flang email list: https://lists.llvm.org/cgi-bin/mailman/listinfo/flang-dev. We will be cross-posting to both flang-dev mailing lists until September.
* Topics for the next biweekly community call and technical community call.
* Let us know if you have presentations or meetings relevant to the Flang community. We will publicize them in these notes.
Details
1. Flang on GitHub
· There have been 1,526 total commits (1,483 in the previous update).
· There are 478 people who have “starred” the flang repo and 69 forks.
· 175 people are following f18 in 26 forks. There have been 2,457 commits.
1. Flang Community Technical Call
* This 30-minute biweekly call is hosted by Hal Finkel at https://bluejeans.com/625064848 on the alternate Mondays on the weeks we do not have this call, at 8:30 AM Pacific time.
* Agenda topics and notes from the calls can be found in this <https://docs.google.com/document/d/1Z2U5UAtJ-Dag5wlMaLaW1KRmNgENNAYynJqLW2j2AZQ/edit#heading=h.oiag5i748hyl> Google doc. It also contains instructions for joining the meeting.
* The most recent call was held August 28th, 8:30 AM Pacific time where there was a discussion about array descriptors and the Fortran 2018 standards for interfacing to the descriptors.
* The next call is scheduled for September 9th. The agenda topic will probably be module files.
* Future Topics and tentative dates:
* LLVM transition (mailing lists, git/monorepo, etc.)
* Module files (September 9)
* DWARF (September 23?)
* Tooling development
* Meeting details:
Meeting URL: https://bluejeans.com/625064848?src=join_info
Meeting ID: 625 064 848
Want to dial in from a phone? Dial one of the following numbers:
+1.408.317.9254 (US (San Jose))
+1.866.226.4650 (US Toll Free)
(see all numbers - https://www.bluejeans.com/premium-numbers)
Enter the meeting ID and passcode followed by #
Connecting from a room system?
Dial: bjn.vc or 199.48.152.152 and enter your meeting ID & passcode
1. Flang community
* Website: www.flang-compiler.org<http://www.flang-compiler.org> redirects to http://github.com/flang-compiler/flang.
* Wiki: https://github.com/flang-compiler/flang/wiki is the Flang wiki page where the most up-to-date build instructions and news can be found.
* Issues: Bug reports for Flang can be reported to https://github.com/flang-compiler/flang/issues.
* LLVM mailing lists: There are now two mailing lists hosted by llvm.org. We will be transitioning to using these lists:
* The flang-dev mailing list has been set up. Subscribe at https://lists.llvm.org/cgi-bin/mailman/listinfo/flang-dev. These biweekly notes will now be sent to this email list.
* The flang-commits mailing list has been set up. Subscribe at https://lists.llvm.org/cgi-bin/mailman/listinfo/flang-commits.
* Please migrate to the LLVM project mailing lists. We will be turning off the flang-dev at lists.flang-compiler.org<mailto:flang-dev at lists.flang-compiler.org> on September 1, 2019.
* Old mailing lists: There are three mailing lists for Flang: flang-dev, flang-sync and flang-announce at http://lists.flang-compiler.org/. These will no longer be used; please use the LLVM mailing lists now.
* You can reach the general Flang community by emailing flang-dev at lists.flang-compiler.org<mailto:flang-dev at lists.flang-compiler.org>.
* Occasional announcements are sent to flang-announce at lists.flang-compiler.org<mailto:flang-announce at lists.flang-compiler.org>.
* These notes will then be sent to flang-dev and flang-sync at lists.flang-compiler.org<mailto:flang-sync at lists.flang-compiler.org>. You should be able to subscribe and unsubscribe yourself from flang-sync and flang-dev as you desire.
* Slack: flang-compiler.slack.com is used for informal real-time communication in the Flang community. Add yourself via the invite <https://join.slack.com/t/flang-compiler/shared_invite/enQtMjExOTEyMzQ3MjIxLTZkMDNlODc2YjgxZDY1NTQ2YWJiZWVhOGU2YWY0NDNiOWY0ZjQzNjYyZTNlZjBlNjgxY2U1ZjFjMmY5NzIwMzA> link.
* Supercomputing 2019
* Hal’s LLVM BoF session at SC 2019 was approved. There is no BoF schedule yet.
* There won’t be a specific LLVM in HPC Workshop this year.
* There may also be a social event. Nothing specific yet.
* LLVM Developer Meeting 2019
* The LLVM Dev Meeting is October 22-23 at the San Jose Convention Center; details can be found here<https://llvm.org/devmtg/2019-10/>.
* Eric Schweitz’s talk, An MLIR Dialect for High-Level Optimization of Fortran<https://llvm.org/devmtg/2019-10/talk-abstracts.html#tech19>, was accepted.
* MLIR for HPC Workshop 2019
* The MLIR for HPC workshop<http://www.cs.utah.edu/~mhall/mlir4hpc/> will be held October 21st in conjunction with the 32nd Workshop on Languages and Compilers for Parallel Computing<https://lcpc19.cc.gatech.edu/> October 22-24 at Georgia tech.
* Some of the usual suspects from the LLVM Developer Meeting will be attending this workshop.
* OpenMPIRBuilder
* Johannes Doerfert provided a brief update on the effort to refactor OpenMP support for Clang (that will ultimately benefit Flang and F18). He has been addressing review comments. He has the Parallel construct done (perhaps minus a clause or two).
1. What we’re up to
* F18 Fortran 2018 compiler
* On GitHub: The source code f18 is available on flang-compiler.github.com/f18<https://github.com/flang-compiler/f18/>. It’s recommended to start in the “documentation” directory.
* Status: We continue development on the new Fortran 2018 front-end. Recent work includes:
* “An MLIR Dialect for High-Level Optimization of Fortran” was accepted for the LLVM Developer Meeting.
* Fixed issues in module file generation, array references, intrinsic calls, intrinsic folding.
* Implemented special handling for VOLATILE and ASYNCHRONOUS attributes.
* Finished conversion of floating-point binary<->decimal templates for use at compile time and run time.
* Worked on user procedure call protocol requirements and design.
* More work on DO loop semantics and constraint checking, including CYCLE statements. Additional semantic checks added.
* More work on OpenMP directive parsing and semantic checks, including Declare directives, block constructs, standalone directives, sections, atomic and critical constructs. Working through tests including SOLLVE.
* The driver “flang” turns on semantic processing by default. This will make it easier for people to check existing codes against f18 and expanding the test suite in f18.
* Craig Rasmussen reports that he has switched to using f18 for the Rose front-end. There’s more work to do, but he reported significant progress here.
* LLVM Project:
* The flang-dev email list has been set up on llvm.org. You can subscribe here: https://lists.llvm.org/cgi-bin/mailman/listinfo/flang-dev. Archives are also available.
* The flang-commits email list has also been set up. There is no content yet, as we haven’t migrated to the LLVM monorepo.
* The plan is to first upload some of the top-level documentation so the community can read the project goals and strategy before we do a big code dump. This should happen mid-June.
* Still blocked on adding flang to the LLVM repo.
* Recent updates to Flang:
Work continues on the Fortran 2008 BLOCK construct. We are working on semantics related to constructs that cause execution to exit scopes and concerns related to optimization.
Continued work on polymorphic allocatable assignment statements.
Started work on debug metadata for inlined procedures (helpful for profiling).
Arm are now committers for flang-compiler/flang-driver.
We updated the CCLA to version 4, based on feedback from Microsoft. Only new contributors need care.
* More PGI bug fixes
* F2008 vector NORM2
* #719 libpgmath: windows and osx support (as PR#770)
* #763 MINLOC intrinsic incorrectly returns last minimum rather than first
* #785 dynamic character pointer return function regression
* Optimized ATAN for x86
* Fixed build issue with runtime library (old module file error)
* Corrected handling of deferred character return types
* Optimized POPCNT intrinsic implementation (more to come)
* Upcoming changes to Flang (in review):
* More PGI bug fixes
* Debug support for Fortran allocatables
* Pull request #573 –libpgmath: make it clang friendly; addresses bug #557 (reviewing)
* Pull request #695 – Remove duplicate files
* Pull request #716 – Make NCAR Kernels tests into longtests
* Assigned for work:
* #226 Unlimited polymorphic type does not work with transfer intrinsic
* #298 norm2 intrinsic
* #402 Compiler error on regular code
* #404 Internal compiler error with polymorphic subroutine parameters and nested derived types
* #426 Failures in #include of OpenMPI's mpif.h
* #461 OpenMP TeaLeaf_ref: local pointer variable not captured into parallel region
* #477 Pull request for module variable import debug test
* #498 Error while compiling libpgmath
* #512 Flang rejects polymorphic assignment
* #577 Procedure pointers to internal procedures
* #602 fd_sincos_scalar.cpp: "error: ‘__builtin_complex’ was not declared in this scope"
* #604 Flang errors out on a final subroutine with parameterized derived types
* #608 gdwarf-<version> flag is not honoured
* #610 No debug generated for namelists
* #662 Regression : Segfault in taskloop code
* #720 Segfault on sourced allocation of polymorphic variable
* #780 Linking CXX shared library libpgmath.dylib fails on macOS
* #781 [Debug] Assertion failure in llvm
* Pull request #573 libpgmath: make it clang friendly; addresses bug #557
* Pull request #695 runtime: remove duplicate files
* Pull request #710 Test case for capturing procedure pointers to OpenMP parallel regions
* Pull request #719 Make the NCAR Kernels tests into longtests
* Pull request #719 libpgmath: windows and osx support
* Outstanding pull requests:
* #521 Add OpenBSD as a recognized OS (pending test on new OpenBSD systems internally)
* #529 runtime: PoC: generate call to LLVM intrinsic instead of calling runtime functions when possible; handling NINT for a beginning (proposed expansion of this pull request)
* #530 AArch64: disable test cases invalid on aarch64 (working on)
* #532 runtime: remove duplicate files (need to validate on all compilers)
* #546 Loosen ties to x86 (working on)
* #572 libpgmath: respect LIBPGMATH_WITH_GENERIC setting; fixes #559 (reviewing)
* #592 add support for macOS (awaiting CLA)
* #622 Add explicit braces to avoid dangling else problem (failed NVIDIA testing)
* #642 AArch64: significantly improve formatted input performance by using optimized libc functions on ARM64
* #647 Introduce buffered I/O and replace getc with buffered read
* #655 Add missing signed integer to a pointer conversion in DATA statement
* #658 Fix in preprocessing for Flexi app
* #659 Changes to support transpose intrinsic during initialization
* #660 Enable support for simd directives
* #672 Support isnan() GNU extension (Arm reviewing)
* #689 Fix for segfault in multiple entries OpenMP functions
* #693 runtime: ARM64 is a 64-bit architecture
* #694 libpgmath sanity: do not call sleep() in Linux systems
* #695 runtime: remove duplicate files
* #701 Fix for ICE in taskloop
* #702 Fix for random_seed when seeds have zeroes in LSB
* #710 Test case for capturing procedure pointers to OpenMP parallel regions
* #711 Make the NCAR Kernels tests into longtests
* #717 Support building libpgmath with clang 6
* #723 Support building flang with clang (closed; fixed in pull request #786)
* #725 Check for gregset_t before using it
* #726 Remove linux references where unneeded
* #737 TRAILZ function added to the fortran compiler (resubmitted)
* #738 Fix for issue #550
* #742 Implement UNROLL directive
* #751 Fix for len intrinsic returning int*8 in some cases
* #752 Fix for ICE in atomic instruction generation
* #756 Fix ICE interf:new_symbol_and_link, symbol not found
* #759 In order to prevent mysterious crashes during parallel building process, build static modules in separate include-static directory (resolved by pull request #792 with shorter fix)
* #760 Rename getcpu() to get_rutime() for compatibility with glibc 2.29 and later
* #762 Force #undef HUGE in runtime/libpgmath/lib/x86_64/libm_amd.h
* #765 Add basic {min,max}loc(..., back=) tests
* #772 Fix unresolved sprintf, fprintf error
* #773 Support for isnan GNU extension: Generate isnanf() & isnan() libm calls
* #775 Introduce a LIBPGMATH_SYSTEM_NAME variable
* #776 The BSDs name 64-bit x86 as amd64
* #778 Fixing NCAR test problems with error tolerance lower than E-12
* Public plan: NVIDIA has published a brief plan for upcoming Flang work on github.io at https://github.com/flang-compiler/flang/wiki/Roadmap. This has been recently updated to reflect current Flang and F18 priorities and to provide better context for the project and its long-term goals.
* Creating pull requests: NVIDIA requires contributor agreements from developers wishing to make pull requests. The Individual CLA is here: https://flang-compiler.github.io/files/Flang-ICLA-v4.pdf. The Corporate CLA is here: https://flang-compiler.github.io/files/Flang-CCLA-v2.pdf. Send completed CLAs to flang-cla at nvidia.com<mailto:flang-cla at nvidia.com>. Assuming the pull request builds and passes “make check-flang”, NVIDIA will take on the internal testing of the pull request using the full test suite available internally and provide feedback to the contributor as appropriate. Once we have the quality of the pull request established, it will be incorporated into Flang.
* LLVM is switching to a new Apache license with LLVM exceptions that we need to incorporate into our CLAs after it is adopted by LLVM community. The LLVM license can be found at http://llvm.org/foundation/relicensing/LICENSE.txt. A web page describing the relicensing effort can be found at http://llvm.org/foundation/relicensing/.
* OpenMP 4.5 support:
o OpenMP 4.5 is supported on multicore CPUs, mapping all target regions across all the cores, with the following known limitations:
* We map the directives directly for host==device with very predictable behavior and good performance results.
* Task depend/priority is not supported
* OMP do clauses linear, order(n), and schedule (modifier) are not supported
* SIMD construct, Declare SIMD, and SIMD clause: private/reduction/lastprivate/collapse clauses on SIMD construct are supported, SIMD clause/construct are used as a hint to vectorize through metadata generation
* There is a bug if target construct is enclosed by task construct
o No update
* Outstanding issues:
* Please refer to the Issues section on GitHub for flang-compiler/flang<https://github.com/flang-compiler/flang/issues> and flang-compiler/flang-driver<https://github.com/flang-compiler/clang/issues>.
* Debug Metadata:
* LLVM Debug metadata changes posted to LLVM Phabricator for review; responding to review comments.
* https://reviews.llvm.org/D54114 [CHARACTER intrinsic data type] Review for this is not complete, and we would like to get additional comments or alternate proposals.
* LLVM Debug metadata changes upstreamed to LLVM:
* https://reviews.llvm.org/D54043 [ELEMENTAL, PURE and RECURSIVE PROCEDURES]
* https://reviews.llvm.org/D54327 [COMMON blocks]
* Packaging and Binary Releases:
* Binary release: We post binary releases at least quarterly. March binary releases of Flang for x86-64 and OpenPOWER (LLVM 7.0) have been posted to http://github.com/flang-compiler/flang/releases.
* Spack: Spack packages for Flang have been reviewed by the Spack team and pulled into Spack for flang_20180921. We are still working through issues with defining the spack package for flang. Brian Homerding is starting to work on Spack changes for the LLVM and Flang for the LLVM Git monorepo.
* Testing updates:
* NCAR Kernels tests take a long time to execute on some architectures, so we are planning to move them to longtests, based on Arm pull request.
* Application updates:
* No update.
1. Fortran 2008 features
Some Fortran 2008 features in development for pgfortran will flow into Flang soon.
* BLOCK construct. Work continues on BLOCK. We are running through a battery of tests.
* Pointer default initialization. Work is scheduled to begin in shortly.
* Allocation of polymorphic variables. Work is scheduled to begin in shortly.
* EXECUTE_COMMAND_LINE intrinsic. Work is scheduled to begin in shortly.
The following items are considered complete. Please report GitHub issues if you identify any problems.
* G0 edit descriptor
* NORM2 intrinsic
* ERROR STOP
* Pointers to internal procedures
* SUBMODULE
* Serial implementation of F2018 DO CONCURRENT (there is no multi-core implementation planned at this time)
* BACK optional argument support for MINLOC/MAXLOC
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