Commit Graph

69 Commits

Author SHA1 Message Date
Xing Xue
2edce427a8
[openmp][AIX]Initial changes for porting to AIX (#76841)
This PR contains initial changes for building and testing libomp on AIX.
More changes will follow.
- `KMP_OS_AIX` is defined for the AIX platform
- `KMP_ARCH_PPC` is defined for 32-bit PPC
- `KMP_ARCH_PPC_XCOFF` and `KMP_ARCH_PPC64_XCOFF` are for 32- and 64-bit
XCOFF object formats respectively
- Assembly file `z_AIX_asm.S` is used for AIX specific assembly code and
will be added in a separate PR
- The target library is disabled because AIX does not have the device
support
- OMPT is temporarily disabled
2024-01-08 08:33:00 -05:00
Andrew Brown
68ea91dd8b
[openmp][wasm] Allow compiling OpenMP to WebAssembly (#71297)
This change allows building the static OpenMP runtime, `libomp.a`, as
WebAssembly. It builds on the work done in [D142593] but goes further in
several ways:
 - it makes the OpenMP CMake files more WebAssembly-aware
- it conditions much more code (or code that had been refactored since
[D142593]) for `KMP_ARCH_WASM` and `KMP_OS_WASI`
- it fixes a Clang crash due to unimplemented common symbols in
WebAssembly

The commit messages have more details. Please understand this PR as a
start, not the completed work, for WebAssembly support in OpenMP.
Getting the tests running somehow would be a good next step, e.g.; but
what is contained here works, at least with recent versions of
[wasi-sdk] and engines that support [wasi-threads]. I suspect the same
is true for Emscripten and browsers, but I have not tested that
workflow.

[D142593]: https://reviews.llvm.org/D142593
[wasi-sdk]: https://github.com/WebAssembly/wasi-sdk
[wasi-threads]: https://github.com/WebAssembly/wasi-threads

---------

Co-authored-by: Atanas Atanasov <atanas.atanasov@intel.com>
2023-12-14 13:48:01 -06:00
Ethan Luis McDonough
2b6ba8c735
[openmp] Tighten flang detection in offloading test
This patch ensures that the locally built version of flang when building in-tree.  `find_program` sometimes used the wrong executable if a different copy of flang was installed.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D159161
2023-09-01 13:59:18 -05:00
Ethan Luis McDonough
9e3d59e4c2
[openmp] Fix flang detection for offloading test
This patch fixes the flang detection in the openmp fortran offloading test.

Reviewed By: jsjodin

Differential Revision: https://reviews.llvm.org/D158546
2023-08-29 16:31:03 -05:00
paperchalice
0beffb8542 [CMake] Ensure CLANG_RESOURCE_DIR is respected.
re-commit of 39aa0f5c43 with missing file:
cmake/Modules/GetClangResourceDir.cmake.
2023-06-03 04:21:35 -07:00
Martin Storsjö
d072d11022 Revert "[CMake] Ensure CLANG_RESOURCE_DIR is respected."
This reverts commit 39aa0f5c43.

This is missing the new GetClangResourceDir.cmake that is being included,
so all clang builds are broken.
2023-06-03 11:47:57 +03:00
paperchalice
39aa0f5c43 [CMake] Ensure CLANG_RESOURCE_DIR is respected. 2023-06-02 23:29:44 -07:00
Mark de Wever
cbaa3597aa Reland "[CMake] Bumps minimum version to 3.20.0.
This reverts commit d763c6e5e2.

Adds the patch by @hans from
https://github.com/llvm/llvm-project/issues/62719
This patch fixes the Windows build.

d763c6e5e2 reverted the reviews

D144509 [CMake] Bumps minimum version to 3.20.0.

This partly undoes D137724.

This change has been discussed on discourse
https://discourse.llvm.org/t/rfc-upgrading-llvms-minimum-required-cmake-version/66193

Note this does not remove work-arounds for older CMake versions, that
will be done in followup patches.

D150532 [OpenMP] Compile assembly files as ASM, not C

Since CMake 3.20, CMake explicitly passes "-x c" (or equivalent)
when compiling a file which has been set as having the language
C. This behaviour change only takes place if "cmake_minimum_required"
is set to 3.20 or newer, or if the policy CMP0119 is set to new.

Attempting to compile assembly files with "-x c" fails, however
this is workarounded in many cases, as OpenMP overrides this with
"-x assembler-with-cpp", however this is only added for non-Windows
targets.

Thus, after increasing cmake_minimum_required to 3.20, this breaks
compiling the GNU assembly for Windows targets; the GNU assembly is
used for ARM and AArch64 Windows targets when building with Clang.
This patch unbreaks that.

D150688 [cmake] Set CMP0091 to fix Windows builds after the cmake_minimum_required bump

The build uses other mechanism to select the runtime.

Fixes #62719

Reviewed By: #libc, Mordante

Differential Revision: https://reviews.llvm.org/D151344
2023-05-27 12:51:21 +02:00
Nico Weber
d763c6e5e2 Revert "Reland "[CMake] Bumps minimum version to 3.20.0.""
This reverts commit 65429b9af6.

Broke several projects, see https://reviews.llvm.org/D144509#4347562 onwards.

Also reverts follow-up commit "[OpenMP] Compile assembly files as ASM, not C"

This reverts commit 4072c8aee4.

Also reverts fix attempt  "[cmake] Set CMP0091 to fix Windows builds after the cmake_minimum_required bump"

This reverts commit 7d47dac5f8.
2023-05-17 10:53:33 -04:00
Martin Storsjö
4072c8aee4 [OpenMP] Compile assembly files as ASM, not C
Since CMake 3.20, CMake explicitly passes "-x c" (or equivalent)
when compiling a file which has been set as having the language
C. This behaviour change only takes place if "cmake_minimum_required"
is set to 3.20 or newer, or if the policy CMP0119 is set to new.

Attempting to compile assembly files with "-x c" fails, however
this is workarounded in many cases, as OpenMP overrides this with
"-x assembler-with-cpp", however this is only added for non-Windows
targets.

Thus, after increasing cmake_minimum_required to 3.20, this breaks
compiling the GNU assembly for Windows targets; the GNU assembly is
used for ARM and AArch64 Windows targets when building with Clang.
This patch unbreaks that.

Differential Revision: https://reviews.llvm.org/D150532
2023-05-16 21:27:35 +03:00
Martin Storsjö
d187ceee3b [OpenMP] Use CMAKE_CXX_STANDARD for setting the C++ version
Previously, we tried to check whether the -std=c++17 option was
supported and manually add the flag. That doesn't work for compilers
that do support C++17 but use a different option syntax, like
clang-cl.

OpenMP itself probably doesn't specifically require C++17, therefore
CXX_STANDARD_REQUIRED is left off, but in some cases, we may
have code that only works in C++17 mode.

In particular, 46262cab24 made a
refactoring that works when built with Clang in C++17 mode, but not
in C++14 mode. MSVC accepts the construct in both language modes.

For libomptarget, we've had specific checks that require C++17
(or the -std=c++17 option) to be supported. It's doubtful that
libomptarget has got any code which more specifically requires C++17;
this seems to be a remnant from when libomptarget was added
originally in 2467df6e4f / D14031.
At that point, the rest of OpenMP didn't require C++11, while
libomptarget did require it. Now, it's unlikely that anyone attempts
building it with a toolchain that doesn't support C++11.

At this point, we could also probably just set CXX_STANDARD_REQUIRED
to true, requiring C++17 as baseline for all the OpenMP libraries.

This fixes building OpenMP with clang-cl after
46262cab24.

Differential Revision: https://reviews.llvm.org/D149726
2023-05-16 10:43:38 +03:00
Mark de Wever
65429b9af6 Reland "[CMake] Bumps minimum version to 3.20.0."
The owner of the last two failing buildbots updated CMake.

This reverts commit e8e8707b4a.
2023-05-13 11:42:25 +02:00
Mark de Wever
e8e8707b4a Revert "Reland "[CMake] Bumps minimum version to 3.20.0.""
Unfortunatly not all buildbots are updated.

This reverts commit ffb807ab53.
2023-05-06 17:03:56 +02:00
Mark de Wever
ffb807ab53 Reland "[CMake] Bumps minimum version to 3.20.0."
All build bots should be updated now.

This reverts commit 44d38022ab.
2023-05-06 11:43:02 +02:00
Mark de Wever
44d38022ab Revert "Revert "Revert "[CMake] Bumps minimum version to 3.20.0."""
This reverts commit 1ef4c3c859.

Two buildbots still haven't been updated.
2023-04-15 20:12:24 +02:00
Mark de Wever
1ef4c3c859 Revert "Revert "[CMake] Bumps minimum version to 3.20.0.""
This reverts commit 92523a35a8.

Reland to see whether CIs are updated.
2023-04-15 13:12:04 +02:00
Mark de Wever
d0398d3593 Revert "Reland "[CMake] Bumps minimum version to 3.20.0.""
This reverts commit a72165e5df.

Some buildbots have not been updated yet.
2023-03-18 20:32:43 +01:00
Mark de Wever
a72165e5df Reland "[CMake] Bumps minimum version to 3.20.0."
This reverts commit 92523a35a8.

Test whether all CI runners are updated.
2023-03-18 13:33:42 +01:00
Mark de Wever
92523a35a8 Revert "[CMake] Bumps minimum version to 3.20.0."
Some build bots have not been updated to the new minimal CMake version.
Reverting for now and ping the buildbot owners.

This reverts commit 44c6b905f8.
2023-03-04 18:28:13 +01:00
Mark de Wever
44c6b905f8 [CMake] Bumps minimum version to 3.20.0.
This partly undoes D137724.

This change has been discussed on discourse
https://discourse.llvm.org/t/rfc-upgrading-llvms-minimum-required-cmake-version/66193

Note this does not remove work-arounds for older CMake versions, that
will be done in followup patches.

Reviewed By: mehdi_amini, MaskRay, ChuanqiXu, to268, thieta, tschuett, phosek, #libunwind, #libc_vendors, #libc, #libc_abi, sivachandra, philnik, zibi

Differential Revision: https://reviews.llvm.org/D144509
2023-03-04 12:40:57 +01:00
Shilei Tian
57662cb2e3 [OpenMP] Disable building libomptarget on 32-bit systems
There are plenty of assumptions in `libomptarget` and the device runtime
about the pointer size or `size_t`, etc. 32-bit systems are not supported. There
is no point to refine whole things to make it portable. This patch simply disables
building on 32-bit systems.

Fix #60121.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D142023
2023-01-18 13:40:08 -05:00
Vignesh Balasubramanian
ae1507d3ea [OpenMP] [OMPD] Enable OMPD Tests
It was disabled due to different failures it different llvm bots.

Reviewed By: ye-luo
Differential Revision: https://reviews.llvm.org/D138411
2022-12-23 11:47:21 +05:30
Joseph Huber
3d2aa5473c [OpenMP][NFC] Fix message to recommend C++17 instead of C++14
Summary:
This was changed in LLVM 16.0.
2022-12-20 13:39:44 -06:00
Mark de Wever
d40dc41738 [CMake] Warn when the version is older than 3.20.0.
This is a preparation to require CMake 3.20.0 after LLVM 16 has been
released.

This change has been discussed on discourse
https://discourse.llvm.org/t/rfc-upgrading-llvms-minimum-required-cmake-version/66193

Reviewed By: #libc_vendors, MaskRay, ChuanqiXu, to268, thieta, stellaraccident, ldionne, #libc, #libc_abi, phosek

Differential Revision: https://reviews.llvm.org/D137724
2022-12-11 20:19:46 +01:00
Vignesh Balasubramanian
a06084ebd2 Revert "[OpenMP] [OMPD] Enable OMPD Tests"
This reverts commit 451c017a32.
2022-11-30 16:37:01 +05:30
Vignesh Balasubramanian
451c017a32 [OpenMP] [OMPD] Enable OMPD Tests
It was disabled due to different failures it different llvm bots.

Reviewed By: ye-luo
Differential Revision: https://reviews.llvm.org/D138411
2022-11-30 15:36:19 +05:30
Joseph Huber
87760910a3 [OpenMP] Fix installation to old resource dir
Summary:
The changes in D125860 renamed the old resource directory to only use
the major version. This was not updated for the OpenMP project, causing
OpenMP resources to still be installed in the old `major.minor.rev`
folder. This lead to problems including the header files.

fixes #58966
2022-11-14 08:21:46 -06:00
serge-sans-paille
6f2ed8fd3f [OpenMP] Install ompt-multiplex.h alongside omp.h
The default install direction may not be in the compiler search path.

Differential Revision: https://reviews.llvm.org/D133420
2022-09-09 09:42:08 +02:00
Joseph Huber
04ae35e592 [libomptarget] Always enable time tracing in libomptarget
Previously time tracing features were hidden behind an optional CMake
option. This was because `libomptarget` was not based on the LLVM
libraries at that time. Now that `libomptarget` is an LLVM library we
should be able to freely use the `LLVMSupport` library whenever we want
and do not need to guard it in this way.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D132852
2022-08-29 14:49:03 -05:00
John Ericson
e941b031d3 Revert "[cmake] Use CMAKE_INSTALL_LIBDIR too"
This reverts commit f7a33090a9.

Unfortunately this causes a number of failures that didn't show up in my
local build.
2022-08-18 22:46:32 -04:00
John Ericson
f7a33090a9 [cmake] Use CMAKE_INSTALL_LIBDIR too
We held off on this before as `LLVM_LIBDIR_SUFFIX` conflicted with it.
Now we return this.

`LLVM_LIBDIR_SUFFIX` is kept as a deprecated way to set
`CMAKE_INSTALL_LIBDIR`. The other `*_LIBDIR_SUFFIX` are just removed
entirely.

I imagine this is too potentially-breaking to make LLVM 15. That's fine.
I have a more minimal version of this in the disto (NixOS) patches for
LLVM 15 (like previous versions). This more expansive version I will
test harder after the release is cut.

Reviewed By: sebastian-ne, ldionne, #libc, #libc_abi

Differential Revision: https://reviews.llvm.org/D130586
2022-08-18 15:33:35 -04:00
Jon Chesterfield
521a5c11ac Rename OPENMP_HAVE_STD_CPP14_FLAG to match c++17 2022-08-08 17:07:45 +01:00
John Ericson
28e665fa05 [cmake] Slight fix ups to make robust to the full range of GNUInstallDirs
See https://cmake.org/cmake/help/v3.14/module/GNUInstallDirs.html#result-variables for `CMAKE_INSTALL_FULL_*`

Reviewed By: sebastian-ne

Differential Revision: https://reviews.llvm.org/D130545
2022-07-26 14:48:49 +00:00
John Ericson
0a6b4258ab [openmp][cmake] Use GNUInstallDirs to support custom installation dirs
I am breaking apart D99484 so the cause of build failures is easier to
understand.

Differential Revision: https://reviews.llvm.org/D117945
2022-01-22 18:05:36 +00:00
John Ericson
da77db58d7 Revert "[cmake] Use GNUInstallDirs to support custom installation dirs."
https://lab.llvm.org/buildbot/#/builders/46/builds/21146 Still have
this odd error, not sure how to reproduce, so I will just try breaking
up my patch.

This reverts commit 4a678f8072.
2022-01-16 05:48:30 +00:00
John Ericson
4a678f8072 [cmake] Use GNUInstallDirs to support custom installation dirs.
This is the original patch in my GNUInstallDirs series, now last to merge as the final piece!

It arose as a new draft of D28234. I initially did the unorthodox thing of pushing to that when I wasn't the original author, but since I ended up

 - Using `GNUInstallDirs`, rather than mimicking it, as the original author was hesitant to do but others requested.

 - Converting all the packages, not just LLVM, effecting many more projects than LLVM itself.

I figured it was time to make a new revision.

I have used this patch series (and many back-ports) as the basis of https://github.com/NixOS/nixpkgs/pull/111487 for my distro (NixOS), which was merged last spring (2021). It looked like people were generally on board in D28234, but I make note of this here in case extra motivation is useful.

---

As pointed out in the original issue, a central tension is that LLVM already has some partial support for these sorts of things. Variables like `COMPILER_RT_INSTALL_PATH` have already been dealt with. Variables like `LLVM_LIBDIR_SUFFIX` however, will require further work, so that we may use `CMAKE_INSTALL_LIBDIR`.

These remaining items will be addressed in further patches. What is here is now rote and so we should get it out of the way before dealing more intricately with the remainder.

Reviewed By: #libunwind, #libc, #libc_abi, compnerd

Differential Revision: https://reviews.llvm.org/D99484
2022-01-16 05:33:07 +00:00
John Ericson
6e52bfe09d Revert "[cmake] Use GNUInstallDirs to support custom installation dirs."
Sorry for the disruption, I will try again later.

This reverts commit efeb501970.
2022-01-15 07:35:02 +00:00
John Ericson
efeb501970 [cmake] Use GNUInstallDirs to support custom installation dirs.
This is the original patch in my GNUInstallDirs series, now last to merge as the final piece!

It arose as a new draft of D28234. I initially did the unorthodox thing of pushing to that when I wasn't the original author, but since I ended up

 - Using `GNUInstallDirs`, rather than mimicking it, as the original author was hesitant to do but others requested.

 - Converting all the packages, not just LLVM, effecting many more projects than LLVM itself.

I figured it was time to make a new revision.

I have used this patch series (and many back-ports) as the basis of https://github.com/NixOS/nixpkgs/pull/111487 for my distro (NixOS), which was merged last spring (2021). It looked like people were generally on board in D28234, but I make note of this here in case extra motivation is useful.

---

As pointed out in the original issue, a central tension is that LLVM already has some partial support for these sorts of things. Variables like `COMPILER_RT_INSTALL_PATH` have already been dealt with. Variables like `LLVM_LIBDIR_SUFFIX` however, will require further work, so that we may use `CMAKE_INSTALL_LIBDIR`.

These remaining items will be addressed in further patches. What is here is now rote and so we should get it out of the way before dealing more intricately with the remainder.

Reviewed By: #libunwind, #libc, #libc_abi, compnerd

Differential Revision: https://reviews.llvm.org/D99484
2022-01-15 01:08:35 +00:00
Martin Storsjö
db32c4f456 [OpenMP] Disable libomptarget profiling by default if built via the "runtimes" setup
In the "runtimes" setup, the runtime (e.g. OpenMP) can be built for
a target entirely different from the current host build (where LLVM
and Clang are built). If profiling is enabled, libomptarget links
against LLVMSupport (which only has been built for the host).

Thus, don't enable profiling by default in this setup.

This should allow relanding D113253.

Differential Revision: https://reviews.llvm.org/D114083
2021-12-07 22:23:50 +02:00
Bran Hagger
9f15cacc2e [OpenMP] Allow building libomp using Microsoft Visual C++ naming scheme
Differential Revision: https://reviews.llvm.org/D110354
2021-11-11 13:11:56 -06:00
Vignesh Balasubramanian
b9a27908f9 [OpenMP][OMPD] Implementation of OMPD debugging library - libompd.
This is a continuation of the review: https://reviews.llvm.org/D100181
Creates a new directory "libompd" under openmp.

"TargetValue" provides operational access to the OpenMP runtime memory
 for OMPD APIs.
With TargetValue, using "pointer" a user can do multiple operations
from casting, dereferencing to accessing an element for structure.
The member functions are designed to concatenate the operations that
are needed to access values from structures.

e.g., _a[6]->_b._c would read like :
TValue(ctx, "_a").cast("A",2)
	.getArrayElement(6).access("_b").cast("B").access("_c")
For example:
If you have a pointer "ThreadHandle" of a running program then you can
access/retrieve "threadID" from the memory using TargetValue as below.

  TValue(context, thread_handle->th) /*__kmp_threads[t]->th*/
    .cast("kmp_base_info_t")
    .access("th_info") /*__kmp_threads[t]->th.th_info*/
    .cast("kmp_desc_t")
    .access("ds") /*__kmp_threads[t]->th.th_info.ds*/
    .cast("kmp_desc_base_t")
    .access("ds_thread") /*__kmp_threads[t]->th.th_info.ds.ds_thread*/
                .cast("kmp_thread_t")
.getRawValue(thread_id, 1);

Reviewed By: @hbae
Differential Revision: https://reviews.llvm.org/D100182
2021-09-01 14:50:16 +05:30
Vyacheslav Zakharin
f2f88f3e7a An attempt to abandon omptarget out-of-tree builds.
I want to start using LLVM component libraries in libomptarget
to stop duplicating implementations already available in LLVM
(e.g. LLVMObject, LLVMSupport, etc.). Without relying on LLVM
in all libomptarget builds one has to provide fallback implementation
for each used LLVM feature.

This is an attempt to stop supporting out-of-llvm-tree builds of libomptarget.

I understand that I may need to revert this,
if this affects downstream projects in a bad way.

Differential Revision: https://reviews.llvm.org/D101509
2021-05-07 12:43:50 -07:00
Shilei Tian
c571b16834 [OpenMP] Disabled profiling in libomp by default to unblock link errors
Link error occurred when time profiling in libomp is enabled by default
because `libomp` is assumed to be a C library but the dependence on
`libLLVMSupport` for profiling is a C++ library. Currently the issue blocks all
OpenMP tests in Phabricator.

This patch set a new CMake option `OPENMP_ENABLE_LIBOMP_PROFILING` to
enable/disable the feature. By default it is disabled. Note that once time
profiling is enabled for `libomp`, it becomes a C++ library.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D95585
2021-01-28 07:24:32 -05:00
Giorgis Georgakoudis
bb40e67318 [OpenMP] Fix building using LLVM_ENABLE_RUNTIMES
Fix when time profiling is enabled.

Related to: D94855

Reviewed By: JonChesterfield

Differential Revision: https://reviews.llvm.org/D95398
2021-01-27 06:43:57 -08:00
Shilei Tian
01f1273fe2 [OpenMP] Fixed a typo in openmp/CMakeLists.txt 2021-01-12 17:00:49 -05:00
Shilei Tian
bdd1ad5e5c [OpenMP] Fixed include directories for OpenMP when building OpenMP with LLVM_ENABLE_RUNTIMES
Some LLVM headers are generated by CMake. Before the installation,
LLVM's headers are distributed everywhere, some of which are in
`${LLVM_SRC_ROOT}/llvm/include/llvm`, and some are in
`${LLVM_BINARY_ROOT}/include/llvm`. After intallation, they're all in
`${LLVM_INSTALLATION_ROOT}/include/llvm`.

OpenMP now depends on LLVM headers. Some headers depend on headers generated
by CMake. When building OpenMP along with LLVM, a.k.a via `LLVM_ENABLE_RUNTIMES`,
we need to tell OpenMP where it can find those headers, especially those still
have not been copied/installed.

Reviewed By: jdoerfert, jhuber6

Differential Revision: https://reviews.llvm.org/D94534
2021-01-12 14:32:38 -05:00
Giorgis Georgakoudis
e007b32864 [OpenMP] Add time profiling for libomptarget
Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D93055
2020-12-11 18:53:37 -08:00
Jon Chesterfield
26790ed248 [libomptarget] Require LLVM source tree to build libomptarget
[libomptarget] Require LLVM source tree to build libomptarget

This is to permit reliably #including files from the LLVM tree in libomptarget,
as an improvement on the copy and paste that is currently in use. See D87841
for the first example of removing duplication given this new requirement.

The weekly openmp dev call reached consensus on this approach. See also D87841
for some alternatives that were considered. In the future, we may want to
introduce a new top level repo for shared constants, or start using the ADT
library within openmp.

This will break sufficiently exotic build systems, trivial fixes as below.

Building libomptarget as part of the monorepo will continue to work.
If openmp is built separately, it now requires a cmake macro indicating
where to find the LLVM source tree.

If openmp is built separately, without the llvm source tree already on disk,
the build machine will need a copy of a subset of the llvm source tree and
the cmake macro indicating where it is.

Reviewed By: protze.joachim

Differential Revision: https://reviews.llvm.org/D89426
2020-10-21 18:53:00 +01:00
Joseph Huber
1c4c21489f [OpenMP] Initial Support for OpenMP Webpage Documentation
Summary:
Adding support for generated html documentation for OpenMP. Changing
Cmake files to build the documentation and adding the base templates for
future documentation to be added.

Reviewers: jdoerfert

Subscribers: aaron.ballman arphaman guansong mgorny openmp-commits sstefan1 yaxunl

Tags: #OpenMP

Differential Revision: https://reviews.llvm.org/D87797
2020-09-18 16:32:22 -04:00
Louis Dionne
afa1afd410 [CMake] Bump CMake minimum version to 3.13.4
This upgrade should be friction-less because we've already been ensuring
that CMake >= 3.13.4 is used.

This is part of the effort discussed on llvm-dev here:

  http://lists.llvm.org/pipermail/llvm-dev/2020-April/140578.html

Differential Revision: https://reviews.llvm.org/D78648
2020-07-22 14:25:07 -04:00