Update to LLVM 12.0.1

[chalcolith]

Supersedes #3731

• Update the LLVM submodule to llvmorg-12.0.0
• Update the JIT code to work with LLVM 12.
• Update custom optimizations to work with LLVM 12.
• Move old JIT and optimization code to separate files for historical reference
• Update handling LLVM library dependencies:
  • Consolidate LLVM library configuration in the root CMakeLists.txt file.
  • Deprecate the llvm_config cmake macro in favour of using individual components with llvm_map_components_to_libnames.
• Include the in-progress work on Mac M1:
  • Update CMakeLists.txt to require C++14 (LLVM now does).
  • Add missing header to cpu.c that is required on Apple M1.

[ponylang-main]

Hi @kulibali,

The changelog - changed label was added to this pull request; all PRs with a changelog label need to have release notes included as part of the PR. If you haven't added release notes already, please do.

Release notes are added by creating a uniquely named file in the .release-notes directory. We suggest you call the file 3745.md to match the number of this pull request.

The basic format of the release notes (using markdown) should be:

## Title

End user description of changes, why it's important,
problems it solves etc.

If a breaking change, make sure to include 1 or more
examples what code would look like prior to this change
and how to update it to work after this change.

Thanks.

[redvers]

I am able to build this using nix somewhat cleanly, except I appear to fail the same test-stdlib-release as some of the CI below:

Building serialise -> /home/red/projects/pony/ponyc/packages/serialise
Generating
 Reachability
 Selector painting
 Data prototypes
 Data types
 Function prototypes
 Functions
 Descriptors
Optimising
Verifying
PHI node operands are not the same type as the result!
  %108 = phi i8* [ %7, %99 ], [ %23, %105 ]
Call parameter type does not match function signature!
  %5 = getelementptr inbounds [32 x i1], [32 x i1]* %4, i64 0, i64 0
 i8*  call void @llvm.memcpy.p0i8.p0i8.i64(i1* nonnull align 8 dereferenceable(5) %5, i8* nonnull align 8 dereferenceable(5) getelementptr inbounds ([6 x i8], [6 x i8]* @9904, i64 0, i64 0), i64 5, i1 false) #2
Call parameter type does not match function signature!
  %5 = getelementptr inbounds [32 x i1], [32 x i1]* %4, i64 0, i64 0
 i8*  %8 = call i32 @bcmp(i8* nonnull dereferenceable(5) getelementptr inbounds ([6 x i8], [6 x i8]* @9904, i64 0, i64 0), i1* nonnull dereferenceable(5) %5, i64 5) #2
Stored value type does not match pointer operand type!
  store i8 102, i1* %6, align 8
 i1Stored value type does not match pointer operand type!
  store i8 97, i1* %19, align 1
 i1Stored value type does not match pointer operand type!
  store i8 108, i1* %20, align 2
 i1Stored value type does not match pointer operand type!
  store i8 115, i1* %21, align 1
 i1Stored value type does not match pointer operand type!
  store i8 101, i1* %22, align 4
 i1Call parameter type does not match function signature!

etc...

[redvers]

The build initially failed as nix configures warnings to be errors by default.

The specific build error I got was this:

In file included from /nix/store/pclcc5kl1bkkns8410f6l0dhrnmxll7x-glibc-2.32-37-dev/include/string.h:519,
                 from /home/red/projects/pony/ponyc/src/ponyc/main.c:15:
In function ‘strncat’,
    inlined from ‘main’ at /home/red/projects/pony/ponyc/src/ponyc/main.c:92:5:
/nix/store/pclcc5kl1bkkns8410f6l0dhrnmxll7x-glibc-2.32-37-dev/include/bits/string_fortified.h:122:10: warning: ‘__builtin_strncat’ specified bound depends on the length of the source argument [-Wstringop-overflow=]
  122 |   return __builtin___strncat_chk (__dest, __src, __len, __bos (__dest));
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/red/projects/pony/ponyc/src/ponyc/main.c: In function ‘main’:
/home/red/projects/pony/ponyc/src/ponyc/main.c:92:5: note: length computed here
   92 |     strncat((char*)opt.all_args, argv[i], strlen(argv[i]));
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

... which I believe refers to this:

https://github.com/ponylang/ponyc/blob/llvm1200/src/ponyc/main.c#L92

[chalcolith]

I have narrowed the LLVM problem to the HeapToStack pass.

[redvers]

I'd got it down as far as not being present in a debug compile so was about to start chewing down the Optimization path.

I doubt I would have the skills yet to get to that level of detail.

I shall wander into the wilderness and start prepping a (nixpkgs) build job for this new branch.

Thanks!

[chalcolith]

This program will reproduce the behaviour:

use "serialise"

actor _EmptyActor

class _HasActor
  let x: _EmptyActor = _EmptyActor

actor Main
  new create(env: Env) =>
    try
      let qwe: _HasActor ref = _HasActor
      let auth = SerialiseAuth(env.root as AmbientAuth)
      let ser = Serialised(auth, qwe)?

      env.out.print("succeeded")
    else
      env.out.print("ELSE")
    end

[SeanTAllen]

@kulibali reproduce what behavior?

[chalcolith]

The Serialised constructor will eventually call ponyint_serialise_actor(), which calls a lambda that calls pony_error(). The call to _Unwind_RaiseException() in pony_error returns with error code _URC_FAILURE, and control never reaches the personality function ponyint_personality_v0.

[chalcolith]

Sorry -- I mean the 32-bit ARM failures.

[chalcolith]

There is some mention of problems with exception handling on ARM https://stackoverflow.com/questions/51673343/clang-with-libc-exceptions

I haven't had time to investigate further.

[chalcolith]

Here is a stacktrace from 32-bit arm:

#0  __libc_do_syscall ()
    at ../ports/sysdeps/unix/sysv/linux/arm/libc-do-syscall.S:44
#1  0xb6dfcee6 in __GI_raise (sig=sig@entry=6)
    at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
#2  0xb6dfdbee in __GI_abort () at abort.c:89
#3  0x0001ce10 in pony_error ()
    at /home/gordon/Dev/Pony/ponyc_llvm1200/src/libponyrt/lang/posix_except.c:41
#4  0x00013ad4 in serialise_$2$6_apply_o ()
    at /home/gordon/Dev/Pony/ponyc_llvm1200/packages/serialise/serialise.pony:105
#5  0x0001c38e in ponyint_serialise_actor (ctx=0xb6dd6e44, actor=0xb3dd6800)
    at /home/gordon/Dev/Pony/ponyc_llvm1200/src/libponyrt/gc/serialise.c:144
#6  0x0001cd18 in pony_traceknown (ctx=0xb6dd6e44, p=0xb3dd6800, t=0x30c10, 
    m=2) at /home/gordon/Dev/Pony/ponyc_llvm1200/src/libponyrt/gc/trace.c:112
#7  0x0001368c in _HasActor_Trace ()
#8  0x0001b7c6 in ponyint_gc_handlestack (ctx=0xb6dd6e44)
    at /home/gordon/Dev/Pony/ponyc_llvm1200/src/libponyrt/gc/gc.c:669
#9  0x0001c4fc in pony_serialise (ctx=0xb6dd6e44, p=0xb6dd0520, t=0x0, 
    out=0xb6dd0560, alloc_fn=0x15264 <serialise_$2$5_apply_oZo>, 
    throw_fn=0x13ac4 <serialise_$2$6_apply_o>)
    at /home/gordon/Dev/Pony/ponyc_llvm1200/src/libponyrt/gc/serialise.c:217
#10 0x00013b74 in serialise_Serialised_ref_create_ooo (this=0xb6dd0540, 

[chalcolith]

Per today's sync we will disable the 32-bit ARM tests for the time being.

[chalcolith]

I have rebased on main and squashed. This should be ready to merge after the next release.

[SeanTAllen]

I dont think this is release note worthy.

Are we basically saying though that we are dropping 32-bit ARM support? I believe so, so we should so that.

[SeanTAllen]

updated

[SeanTAllen]

@kulibali if you dont get to it before me, i can update the release notes this evening.

[SeanTAllen]

I updated the release notes.