Changes

[lldb] Configure LLDB_FRAMEWORK_DIR in multi-generator builds

[libc++] Fix tests on GCC 10

Also, remove workarounds for ancient Clangs from is_constructible tests.

[lldb] Also configure lldb_framework_dir in the lit.site.cfg.py

Configuring the variable in CMake isn't enought, because the build mode
can't be resolved until execution time, which requires the build mode to
be substituted by lit.

[InstCombine] visitTrunc - remove dead trunc(lshr (zext A), C) combine. NFCI.

I added additional test coverage at rG7a55989dc4305 - but all are handled independently of this combine and http://lab.llvm.org:8080/coverage/coverage-reports/ indicates the code is never used.

Differential revision: https://reviews.llvm.org/D88492

[InstCombine] Fix the outofrange tests and add exact shift tests for D88429

[libc++] Add a regression test for erasing from a vector

After rebasing my trivially-relocatable branch, this behavior was broken...
but no libc++ unit test caught it! Add a regression test specifically for
erasing out of a vector.

Differential Revision: https://reviews.llvm.org/D88421

[flang][msvc] Avoid templated initializer list initialization of vector. NFC.

The Microsoft compiler emits an error when populating the vector with a single element of a templated argument using the brace syntax. The error is:
```
constant.h(102,1): error C2664: 'std::vector<Fortran::evaluate::value::Complex<...>, ...>::vector(std::initializer_list<_Ty>,const _Alloc &)': cannot convert argument 1 from 'initializer list' to 'std::initializer_list<_Ty>'
```
To work around this error, we replace the templated constructor with one for the expected type. Conversion to the element type has to be done by the caller.

This patch is part of the series to make flang compilable with MS Visual Studio <http://lists.llvm.org/pipermail/flang-dev/2020-July/000448.html>.

Reviewed By: klausler

Differential Revision: https://reviews.llvm.org/D88163

[COFF][CG Profile] set undefined symbol to external

Differential Revision: https://reviews.llvm.org/D88456

[libc++][ci] Update how we build the Docker image

This fixes a couple of issues, such as failing filesystem tests (due to
running the tests as root), and not running with the GCC we downloaded.

[clangd] findNearbyIdentifier(): guaranteed to give up after 2^N lines

As @kadircet mentions in D84912#2184144, `findNearbyIdentifier()` traverses the whole file if there is no identifier for the word.
This patch ensures give up after 2^N lines in any case.

Reviewed By: sammccall

Differential Revision: https://reviews.llvm.org/D87891

[lldb] Remove redundant ctor call (NFC)

As pointed out by Pavel in D88249.

[mlir][openacc] Add shutdown operation

This patch introduces the acc.shutdown operation that represents an OpenACC shutdown directive.
Clauses are derived from the spec 2.14.2

Reviewed By: ftynse

Differential Revision: https://reviews.llvm.org/D88272

[BuildLibCalls] Add noundef to the returned pointers of allocators and argument of free

This patch adds noundef to the returned pointers of allocators (malloc, calloc, ...)
and the pointer argument of free.
The returned pointer of allocators cannot be poison or (partially) undef.
Since the pointer that is given to free should precisely have zero offset,
it cannot be poison or (partially) undef too.

For the size arguments of allocators, noundef wasn't attached simply because
I wasn't sure whether attaching it is okay or not.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D87984

LanaiSubtarget.h - remove unnecessary includes. NFCI.

TargetFrameLowering.h is guaranteed to be covered by LanaiFrameLowering.h

LanaiTargetMachine.h - remove unnecessary includes. NFCI.

[InstCombine] fix weird formatting in test file; NFC

It apparently didn't cause trouble for the parser or FileCheck,
but it was confusing to see a function def split by asserts.

[ELF] Fix multiple -mllvm after D70378

Fixes https://reviews.llvm.org/D70378#2299569 Multiple -mllvm is intended to be supported.

We don't have a proper test for `-plugin-opt=-`. This patch adds the test as well.

Differential Revision: https://reviews.llvm.org/D88461

[InstCombine] visitTrunc - trunc (*shr (trunc A), C) --> trunc(*shr A, C)

Attempt to fold trunc (*shr (trunc A), C) --> trunc(*shr A, C) iff the shift amount if small enough that all zero/sign bits created by the shift are removed by the last trunc.

Helps fix the regressions encountered in D88316.

I've tweaked a couple of shift values as suggested by @lebedev.ri to ensure we have coverage of shift values close (above/below) to the max limit.

Differential Revision: https://reviews.llvm.org/D88429

[InstCombine] adjust duplicate test for masked load; NFC

The test after the changed test was checking exactly the same dereferenceable bytes.

Add -fprofile-update={atomic,prefer-atomic,single}

GCC 7 introduced -fprofile-update={atomic,prefer-atomic} (prefer-atomic is for
best efforts (some targets do not support atomics)) to increment counters
atomically, which is exactly what we have done with -fprofile-instr-generate
(D50867) and -fprofile-arcs (b5ef137c11b1cc6ae839ee75b49233825772bdd0).
This patch adds the option to clang to surface the internal options at driver level.

GCC 7 also turned on -fprofile-update=prefer-atomic when -pthread is specified,
but it has performance regression
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89307). So we don't follow suit.

Differential Revision: https://reviews.llvm.org/D87737

[NFC][regalloc] Unit test for AllocationOrder iteration.

Added unittests. In the process, separated core construction - which just
needs the hits, order, and 'HardHints' values - from construction from
current register allocation state, to simplify testing.

Differential Revision: https://reviews.llvm.org/D88455

Adds MLIR C-API for marshaling Python capsules.

* Providing stable, C-accessible definitions for bridging MLIR Python<->C APIs, we eliminate inter-extension dependencies (i.e. they can all share a diamond dependency on the MLIR C-API).
* Just provides accessors for context and module right now.
* Needed in NPComp in ~a week or so for high level Torch APIs.

Differential Revision: https://reviews.llvm.org/D88426

[gn build] Port 6d193ba3337

[MLIR] Add Async dialect with trivial async.region operation

Start Async dialect for modeling asynchronous execution.

Reviewed By: mehdi_amini, herhut

Differential Revision: https://reviews.llvm.org/D88459

[clangd] Fix assertion in remote-index marshalling

convert_to_slash is a no-op on posix style.