Commit Graph

1915 Commits

Author SHA1 Message Date
Kai Luo 9635168083 [AIX][cmake] Set atomics related macros when build with xlclang
Set `HAVE_CXX_ATOMICS_WITHOUT_LIB` or `HAVE_LIBATOMIC` when build LLVM with xlclang. With these macros set, libraries like libLLVMSupport are able to know whether it's necessary to add `-latomic` to dependent system libs. If `HAVE_LIBATOMIC` is set, `llvm-config --system-libs` appends `-latomic` to its output.

Reviewed By: jsji

Differential Revision: https://reviews.llvm.org/D111782
2021-10-18 09:18:05 +00:00
Noah Shutty 2de43d4202 [CMake] Add optional libCURL dependency to llvm build configuration
This finds the curl libraries if LLVM_ENABLE_CURL is set. This is needed
to implement the debuginfod client library in LLVM.

Patch By: noajshu

Differential Revision: https://reviews.llvm.org/D111238
2021-10-13 10:58:10 -07:00
TN Khanh fe2b2cb58e Add .cmt and .cmti files for OCaml bindings
We can build .cmt and .cmti files for easier
code navigation for OCaml bindings
2021-10-05 19:36:12 +05:30
Petr Hosek 0c4a75f193 [CMake] Remove the LLD LTO check for Darwin
LLD now supports LTO on Darwin.

Differential Revision: https://reviews.llvm.org/D110881
2021-09-30 14:00:31 -07:00
Frederic Cambus 5b125a49ba [CMake] Add detection for the mold linker in AddLLVM.cmake.
mold says it is compatible with GNU ld and gold linkers:

```
$ mold -v
mold 0.9.5 (compatible with GNU ld and GNU gold)
```

And thus it currently gets detected as Gold.

With the following diff, CMake now correctly reports the linker name, and mold keeps being identified as Gold internally for now.

Reviewed By: ldionne, MaskRay

Differential Revision: https://reviews.llvm.org/D110035
2021-09-28 17:46:52 +05:30
Petr Hosek d893692024 [CMake] Pass through CMAKE_READELF to subbuilds
This matches handling of other CMake variables.

Differential Revision: https://reviews.llvm.org/D110463
2021-09-24 18:20:30 -07:00
Nico Weber 4a45f95e76 [llvm] Remove LLVM_CHECK_ENABLED_PROJECTS again
This reverts commit 55f0b33708 and
follow-up reverts commit e9ea03c62c.

LLVM_EXTERNAL_PROJECTS is sufficient, see https://reviews.llvm.org/D110016
2021-09-24 18:49:55 -04:00
Petr Hosek 093245ed9e [CMake] Pass llvm-readelf to CMake external builds
This matches other LLVM binary tools.

Differential Revision: https://reviews.llvm.org/D110313
2021-09-23 14:16:14 -07:00
Nico Weber e9ea03c62c [llvm] Pass LLVM_CHECK_ENABLED_PROJECTS through in cross builds 2021-09-21 09:01:37 -04:00
Nico Weber 9197834535 Revert "Fix CLANG_ENABLE_STATIC_ANALYZER=OFF building all analyzer source"
This reverts commit 6d7b3d6b3a.
Breaks running cmake with `-DCLANG_ENABLE_STATIC_ANALYZER=OFF`
without turning off CLANG_TIDY_ENABLE_STATIC_ANALYZER.
See comments on https://reviews.llvm.org/D109611 for details.
2021-09-20 16:18:03 -04:00
Alex Richardson 6d7b3d6b3a Fix CLANG_ENABLE_STATIC_ANALYZER=OFF building all analyzer source
Since https://reviews.llvm.org/D87118, the StaticAnalyzer directory is
added unconditionally. In theory this should not cause the static analyzer
sources to be built unless they are referenced by another target. However,
the clang-cpp target (defined in clang/tools/clang-shlib) uses the
CLANG_STATIC_LIBS global property to determine which libraries need to
be included. To solve this issue, this patch avoids adding libraries to
that property if EXCLUDE_FROM_ALL is set.

In case something like this comes up again: `cmake --graphviz=targets.dot`
is quite useful to see why a target is included as part of `ninja all`.

Reviewed By: thakis

Differential Revision: https://reviews.llvm.org/D109611
2021-09-20 12:55:56 +01:00
David Tenty 26b8031774 [CMake][AIX] Disable visibility options in build
Visibility options currently have limited support on AIX and may cause warnings or errors
depending on the build compiler used.

Reviewed By: ZarkoCA

Differential Revision: https://reviews.llvm.org/D108467
2021-09-14 16:05:12 -04:00
Nico Weber 8cfab5de13 [Windows build] Use "DIA SDK" in sysroot
This updates llvm/utils/sysroot.py to include the "DIA SDK" folder in the
sysroot.

It also updates the build to look for the DIA SDK there if a sysroot is set.

This requires moving LLVM_WINSYSROOT to config-ix.cmake.

For the GN build, I chose to pass a qualified path to diaguids in libs instead
of pushing a config with a `/libpath:` flag. The former requires a GN with
https://gn-review.googlesource.com/c/gn/+/12200, the latter requires D109624.
The former is more like the cmake build, arguably a bit simpler, and it's
easier to check for the wrong GN revision and easier to update GN.

Differential Revision: https://reviews.llvm.org/D109708
2021-09-14 08:59:28 -04:00
Nico Weber f78f613bb7 [llvm cmake] replace tabs with spaces in config-ix.cmake 2021-09-14 08:58:59 -04:00
Stella Stamenova 584a5d171e Remove obsolete msvc workaround from AddLLVM.cmake
The original change to add the workaround is from 10 years ago and a lot has happened with msvc and cmake and llvm's usage of cmake since and we no longer need the workaround for any scenarios that I am aware of. Build more is now correctly configured for multi-configuration generators such as Visual Studio.

The workaround is, however, causing issues with some of the recent mlir tests as because of the workaround we cannot correctly determine whether assertions are enabled (see https://reviews.llvm.org/D105961).

The original change is:

```
commit b46fdac460
Author: Andrew Trick <atrick@apple.com>
Date:   Tue Jun 28 16:32:01 2011

    cmake: Our MSVC build does not support config-time build mode.

    llvm-svn: 134008
```

Reviewed By: mehdi_amini

Differential Revision: https://reviews.llvm.org/D109521
2021-09-09 10:49:34 -07:00
Fangrui Song 813235947d [CMake] Don't add -Wnon-virtual-dtor if affected by GCC PR102168
See the discussion on
https://reviews.llvm.org/rG4852c770fe8703145dd2a35395985646ce57a454
The GCC behavior (https://gcc.gnu.org/PR102168) seems unhelpful.

Unconditional -Wnon-virtual-dtor led to other unnecessary workarounds like
6df09d6ccb

This patches uses a variant of the 4bb5f44c70
check to detect GCC PR102168.

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D109404
2021-09-07 23:36:47 -07:00
Hans Wennborg c364dcbf1f Add llvm-ml to LLVM_TOOLCHAIN_TOOLS (PR50536)
so that it gets installed in LLVM_INSTALL_TOOLCHAIN_ONLY builds,
such as used by the Windows installer.

Differential revision: https://reviews.llvm.org/D109358
2021-09-07 16:55:29 +02:00
Brad Smith 89f0587154 [CMake] Re-enable use --gc-sections on OpenBSD
Most archs have switched to lld.
2021-09-04 14:18:30 -04:00
Chris Bieneman 2856719d74 [CMake] Add targets for generating coverage reports
This is a pretty small bit of CMake goop to generate code coverage
reports. I always forget the right script invocation and end up
fumbling around too much.

Wouldn't it be great to have targets that "Just Work"?

Well, I thought so.

At present this only really works correctly for LLVM, but I'll extend
it in subsequent patches to work for subprojects.

Reviewed By: phosek

Differential Revision: https://reviews.llvm.org/D109019
2021-09-03 10:45:55 -05:00
Fangrui Song a26b09cb98 [CMake] Remove unneeded -Wdelete-non-virtual-dtor availability check
Available and good in Clang 3.5/GCC 5.
2021-08-31 11:19:04 -07:00
Fangrui Song 4bb5f44c70 [CMake] Remove unneeded -Wnon-virtual-dtor availability check
For Clang, 3.5 is the minimum requirement which has fixed the bug.
GCC 5 is good as well.
2021-08-31 11:00:16 -07:00
Anton Afanasyev b1b68b4c01 [CMake] Add `--gdb-index` option to linker if split dwarf compiling
The option `--gdb-index` should be passed to linker if compiler is invoked
with `-gsplit-dwarf` option. This allows debugger to locate the appropriate
units quickly. See "Invocation" section here: https://gcc.gnu.org/wiki/DebugFission

Suggested by @dblaikie here: https://reviews.llvm.org/D68556#1698442

Differential Revision: https://reviews.llvm.org/D108776
2021-08-30 12:23:21 +03:00
Shoaib Meenai cd1b950141 [cmake] Fix native tooling when cross-compiling on Linux
At least as of CMake 3.20.3, the CMake platform file for Linux doesn't
define the file type prefix and suffix variables, relying on them being
implicitly empty when they're unset. If we're cross-compiling targeting
Windows on a Linux machine, the values of these prefixes and suffixes
populated by the Windows platform file will still be set after including
the Linux platform file, so we'll incorrectly assume the ".exe" suffix
for the host machine. Explicitly unset the variables before including
the platform file, to prevent any previous values from leaking. Thanks
@beanz for suggesting the fix.

Reviewed By: beanz

Differential Revision: https://reviews.llvm.org/D108473
2021-08-20 10:05:13 -07:00
Daniil Fukalov 25ec252537 [CMake] Fix recompile all .inc files with LLVM_OPTIMIZED_TABLEGEN in Visual Studio.
After some moment VS solution generated with LLVM_OPTIMIZED_TABLEGEN started to
generate all .inc files for each build. The reason was it had
"<path to native tablegen>/llvm-tblgen" without .exe as a dependency.

Differential Revision: https://reviews.llvm.org/D107898
2021-08-18 10:24:58 +03:00
Stephen Neuendorffer af78180936 [cmake] Properly support target properties.
It's sometimes useful to use these directives when dealing with
external projects:
target_link_directories
target_link_libraries
target_include_directories

However, under certain circumstances,
llvm_add_library can generate multiple targets.  We need to transfer
these properties to the new targets.  Note that using a generator
expression is necessary because these properties will only be set
after llvm_add_library is called.

Differential Revision: https://reviews.llvm.org/D108098
2021-08-17 14:08:21 -07:00
Harald van Dijk 957334382c
[ExecutionEngine] Check for libunwind before calling __register_frame
libgcc and libunwind have different flavours of __register_frame. Both
 flavours are already correctly handled, except that the code to handle
the libunwind flavour is guarded by __APPLE__. This change uses the
presence of __unw_add_dynamic_fde in libunwind instead to detect whether
libunwind is used, rather than hardcoding it as Apple vs. non-Apple.

Fixes PR44074.

Thanks to Albert Jin <albert.jin@gmail.com> and Chris Schafmeister
<chris.schaf@verizon.net> for identifying the problem.

Reviewed By: lhames

Differential Revision: https://reviews.llvm.org/D106129
2021-08-15 13:35:53 +01:00
Martin Storsjö 592adb0b24 [CMake] Make the vendor part of default mingw triples consistent
Consistently use 'w64' as vendor string; it was 'pc' for the original
i686 triple added in 91bd6c922d, but the later x86_64 triple
used 'w64' as vendor, added in d6c1f37f86.

When the arm triples were added in c84ad73a27, the differing
vendors were copied over accidentally to the arm targets too.

When using per-target runtime directories, having inconsistent vendor
parts of the target triples is fatal.

Differential Revision: https://reviews.llvm.org/D107894
2021-08-12 13:27:09 +03:00
Martin Storsjö c84ad73a27 [CMake] Improve GetHostTriple for Windows/ARM configurations
In MSVC mode, CMake provides CMAKE_C_COMPILER_ARCHITECTURE_ID,
which should be accurate for what the compiler produces. Keep
the old CMAKE_C_SIZEOF_VOID_P based fallback in case this
doesn't provide matches.

In GCC/MinGW mode, CMake doesn't provide that. As we're trying to
guess the default host architecture, use CMAKE_HOST_SYSTEM_PROCESSOR
in combination with the existing CMAKE_C_SIZEOF_VOID_P check to
estimate whether it's x86/x86_64/arm/aarch64.

Differential Revision: https://reviews.llvm.org/D107626
2021-08-09 11:31:28 +03:00
Michał Górny 889a1e69bd [llvm] [cmake] Export LLVM_ENABLE_NEW_PASS_MANAGER into LLVMConfig.cmake
Include the vaue of LLVM_ENABLE_NEW_PASS_MANAGER in generated
LLVMConfig.cmake since it is needed by clang's build system.  This fixes
test failures when the new pass manager is enabled (i.e. by default)
by having clang's CMake files correctly detect that and skip relevant
tests.

Differential Revision: https://reviews.llvm.org/D107628
2021-08-06 20:39:38 +02:00
Tomasz Kamiński f1ab60e40d Fix FindZ3.cmake to support static libraries and Windows
Use absolute path to link z3 to allow builds both on windows and linux
since the library name is platform dependent for Z3 (libz3 on Windows
and z3 on Linux) and MSVC does not recognized -L and -l options.
Fix CMAKE_CROSSCOMPILING that does not work correctly since it uses
Z3_BUILD_VERSION instead of Z3_BUILD_NUMBER
Fix building with the static version of z3 library (supersedes D80227).

 - Build the Z3 version detection code as C++, since the static
   library brings in libstdc++ symbols
 - Detect threading support and link against threading, in the
   (likely) case Z3 was built with threads

Exposed compilation error from building a program that is used to detect
z3 version in the warning message, to simplify troubleshooting.

Reviewed By: JDevlieghere

Differential Revision: https://reviews.llvm.org/D106131
2021-07-29 10:55:44 +02:00
Patrick Holland dbed061bf1 [MCA] Moving the target specific CustomBehaviour impl. from /tools/llvm-mca/ to /lib/Target/.
Differential Revision: https://reviews.llvm.org/D106775
2021-07-28 11:23:18 -07:00
Markus Böck ffe32b5c71 [CMake] Add LIBXML2_DEFINITIONS when testing for symbol existance
Currently when linking LLVM against Libxml2, a simple check is performed to check whether it can be linked successfully. This check currently adds the include directories and the libraries for libxml2, but not definitions found by the config.

This causes issues on Windows when trying to link against a static libxml2. Libxml2 requires LIBXML_STATIC to be defined in the preprocessor to be able to link statically. This definition is put into LIBXML2_DEFINITIONS in the cmake config, but not properly forwarded to check_symbol_exists leading to it failing as it could not find xmlReadMemory in a DLL.

This patch simply appends the content of LIBXML2_DEFINITIONS to the symbol check definitions, fixing the issue.

Differential Revision: https://reviews.llvm.org/D106740
2021-07-24 09:55:14 +02:00
Azharuddin Mohammed 8da3b7d857 [CMake] Don't LTO optimize targets on Darwin, but only if its not ThinLTO
This is just a workaround. Pass the `-mllvm,-O0` link flags only if its
not ThinLTO. Doing that with ThinLTO currently results in an error:

```
Remaining virtual register operands
UNREACHABLE executed at .../llvm/lib/CodeGen/MachineRegisterInfo.cpp:209!
```
2021-07-23 22:38:35 -07:00
Stella Stamenova 328bb2caae [cmake] Export LLVM_HOST_TRIPLE in the LLVMConfig.cmake
This is referenced in several of the cmake files that are part of an llvm install and it is also useful by downstream components such as onnx-mlir.

Differential Revision: https://reviews.llvm.org/D106686
2021-07-23 15:52:36 -07:00
Martin Storsjö b22bf7e82a [CMake] Add version to libLLVM also on non-UNIX
As discussed in https://reviews.llvm.org/D87521

llvm-config expects versioned library regardless of platform.

Reviewed By: mstorsjo

Differential Revision: https://reviews.llvm.org/D89009
2021-07-23 23:05:55 +03:00
Tom Stellard 4cef90d972 cmake: Remove unused property on some targets: LLVM_LINK_LIBS
This doesn't appear to be used anywhere.

Reviewed By: serge-sans-paille

Differential Revision: https://reviews.llvm.org/D100021
2021-07-22 20:00:18 -07:00
Mara Sophie Grosch 5b93e3a75f Add llvm-readobj and binutils symlinks to LLVM_TOOLCHAIN_TOOLS
This patch adds llvm-readobj and the binutils symlink for readelf to
LLVM_TOOLCHAIN_TOOLS.

Tvoid *thread, void *attr,hey are required by some (most?)
autoconf-built libraries, adding these allows me to build newlib with
the toolchain generated this way.

Also opened an issue for that some days ago, see
https://bugs.llvm.org/show_bug.cgi?id=50698

Reviewed By: sbc100

Differential Revision: https://reviews.llvm.org/D104957
2021-07-22 16:33:51 -07:00
Haruki Imai 62cc3cdda6 [CMake] Disable -fno-semantic-interposition for GCC<10.3 on SystemZ
`-fno-semantic-interposition` was added for GCC in D102453, but some MLIR tests
on SystemZ failed with GCC<10.3 due to a bug.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D105453
2021-07-08 22:09:21 -07:00
Daniel Rodríguez Troitiño 48088425b3 [cmake] Invoke strip without -l and with non-grouped flags.
`llvm-strip` does not support `-l`. Apple's `strip` supports `-l`, but
it is not documented, and the latest code doesn't seem to do anything
meaningful. From the old source code drops it seems that `-l` was added
around version 795 of cctools and removed before 898. The code around
the flag usage in 795 talks about problems with kext and forcing the
execution of `ld -r`, which seems a behaviour that is not enforceable in
latest versions of cctools.

The `-l` flag was added in https://reviews.llvm.org/D15133 without a lot
of explanation.

Since the flag is not active, removing it should not modify the
behaviour for most people (except if someone is trying to compile LLVM
with a really old version of `strip`).

Additionally, break the invocation into two different flags, since
`llvm-strip` doesn't at the moment support grouped flags, and other
`strip` implementations should work the same no matter if grouped or
not.

Test Plan:

Using `strip` from Xcode 12.5 in Big Sur to strip the same binary (a
simple Hello World), using both `-Sxl` and `-Sx` produces exactly the
same binary.

Repeating the same process with `clang` results also in the same binary.

Reviewed By: smeenai

Differential Revision: https://reviews.llvm.org/D105243
2021-07-01 13:37:58 -07:00
Tobias Gysi 8eb4b3e2be [CMake][MLIR][Linalg] Adding variable to specify tablegen file dependencies.
Synchronizing multiple custom targets requires not only target but also
file dependencies. Building Linalg involves running yaml-gen followed by
tablegen. Currently, these custom targets are only synchronized using a
target dependency resulting in issues in specific incremental build
setups (https://llvm.discourse.group/t/missing-build-cmake-tblgen-dependency/3727/10).

This patch introduces a novel LLVM_TARGET_DEPENDS variable to the
TableGen.cmake file to provide a way to specify file dependencies.
Additionally, it adapts the Linalg CMakeLists.txt to introduce the
necessary file dependency between yaml-gen and tablegen.

Differential Revision: https://reviews.llvm.org/D105272
2021-07-01 18:54:30 +00:00
Jacob Hegna 96f15aa5bb Fail gracefully if no inlining model is available to download.
Differential Revision: https://reviews.llvm.org/D104829
2021-07-01 04:04:11 +00:00
Petr Hosek aac4de989e [CMake] Don't LTO optimize targets on Darwin either
This is a follow up to D102732 which also expands the logic to Darwin.

Differential Revision: https://reviews.llvm.org/D104764
2021-06-24 10:02:03 -07:00
Jacob Hegna f86d1f99b3 Remove ML inlining model artifacts.
They are not conducive to being stored in git. Instead, we autogenerate
mock model artifacts for use in tests. Production models can be
specified with the cmake flag LLVM_INLINER_MODEL_PATH.

LLVM_INLINER_MODEL_PATH has two sentinel values:
 - download, which will download the most recent compatible model.
 - autogenerate, which will autogenerate a "fake" model for testing the
 model uptake infrastructure.

Differential Revision: https://reviews.llvm.org/D104251
2021-06-21 17:38:09 +00:00
Jacob Hegna 6c848c28c2 Remove redundant environment variable XLA_FLAGS.
If the flag is not set, the script saved_model_aot_compile.py in tensorflow will
default it to the correct value. However, in TF 2.5, the way the value is set in
TensorFlowCompile.cmake file triggers a build error.

Reviewed By: mtrofin

Differential Revision: https://reviews.llvm.org/D103972
2021-06-14 23:58:22 +00:00
Kristina Bessonova 8e62797963 [lit] Attempt for fix tests failing because of 'warning: non-portable path to file'
This is an attempt to fix clang test failures due to 'nonportable-include-path'
warnings on Windows when a path to llvm-project's base directory contains some
uppercase letters (excluding a drive letter).

The issue originates from 2 problems:
* discovery.py loads site config in lower case causing all the paths
based on __file__ and requested within the config file to be in lowercase as well,
* neither os.path.abspath() nor os.path.realpath() (both used to obtain paths of
config files, sources, object directories, etc) do not return paths in the correct
case for Windows (at least consistently for all python versions).

As os.path library doesn't seem to provide any relaible way to restore
the case for paths on Windows, this patch proposes to use pathlib.resolve().
pathlib is a part of Python 3.4 while llvm lit requires Python 3.6.

Reviewed By: Meinersbur

Differential Revision: https://reviews.llvm.org/D103014
2021-06-12 12:49:03 +02:00
Fangrui Song a96f875fe9 [CMake][ELF] Add -fno-semantic-interposition for GCC and Clang>=13
In a `-DCMAKE_BUILD_TYPE=Release -DLLVM_TARGETS_TO_BUILD=X86 -DLLVM_LINK_LLVM_DYLIB=on -DCLANG_LINK_CLANG_DYLIB=on`
build, libLLVM-13git.so is 2% smaller and libclang-cpp.so is 1% smaller (on top of -Wl,-Bsymbolic-functions).
There may be some small performance improvement as well because GCC
-fPIC suppresses interprocedural optimizations for non-inline
definitions by default.

Note: we cannot add -fno-semantic-interposition for Clang<13.  Clang<13's
implementation additionally optimizes global variables, which is incompatible
with unfortunate ELF -fno-pic default: direct access relocations for external
data. If the executable has a -fno-pic object file referencing a global variable
declared in a public header, the direct access relocation will cause a copy
relocation. The executable and libLLVM.so/libclang-cpp.so will disagree on the
address.

Reviewed By: phosek

Differential Revision: https://reviews.llvm.org/D102453
2021-06-03 15:26:34 -07:00
Reid Kleckner ef4cfd8322 Pass -gcodeview-ghash when using clang-cl and lld-link
This precomputes some hashes that LLD uses for type merging to speed up
linking when PDBs are enabled. Only do this if any kind of /DEBUG flag
is passed to the linker. -gcodeview-ghash is orthogonal to /Z7, -g, -g1,
or -gmlt, so it is safe to set it independently from those flags. It
will not increase debug info emission.

Differential Revision: https://reviews.llvm.org/D103287
2021-05-27 20:49:17 -07:00
Petr Hosek 757a851a2c [CMake] Don't LTO optimize targets that aren't part of any distribution
When using distributions, targets that aren't included in any
distribution don't need to be as optimized as targets that are
included since those targets are typically only used for tests.

We might consider avoiding LTO for these targets altogether, see
https://lists.llvm.org/pipermail/llvm-dev/2021-April/149843.html

Differential Revision: https://reviews.llvm.org/D102732
2021-05-19 15:02:11 -07:00
Mariusz Ceier 9383e9c1e6 Fix lld macho standalone build by including llvm/Config/llvm-config.h instead of llvm/Config/config.h
lld/MachO/Driver.cpp and lld/MachO/SyntheticSections.cpp include
llvm/Config/config.h which doesn't exist when building standalone lld.

This patch replaces llvm/Config/config.h include with llvm/Config/llvm-config.h
just like it is in lld/ELF/Driver.cpp and HAVE_LIBXAR with LLVM_HAVE_LIXAR and
moves LLVM_HAVE_LIBXAR from config.h to llvm-config.h

Also it adds LLVM_HAVE_LIBXAR to LLVMConfig.cmake and links liblldMachO2.so
with XAR_LIB if LLVM_HAVE_LIBXAR is set.

Differential Revision: https://reviews.llvm.org/D102084
2021-05-19 11:15:07 -04:00
Mateusz Mikuła fd5e79ff12 [MinGW] Fix the cmake condition for -mbig-obj
This is a correction to D102419, fixing the condition to the
form that actually works as intended.
2021-05-18 23:48:15 +03:00
Petr Hosek 832f7af283 [CMake] Use -O0 for unittests under full LTO as well
We already use -O0 for unittests under ThinLTO, do the same for full LTO
where the compile time costs to runtime benefits tradeoff is even worse.

Differential Revision: https://reviews.llvm.org/D102718
2021-05-18 13:41:32 -07:00
Mateusz Mikuła bf95a8cf86 [MinGW] Always enable -mbig-obj for LLVM build unless using Clang
It's easy to hit 2**16 limit with i686 GNU toolchains these days.
Clang does it automagically, so it's not needed there, and the option
causes warnings about being unused when linking.

Differential Revision: https://reviews.llvm.org/D102419
2021-05-14 23:47:50 +03:00
Oliver Stannard 92260d7a18 Revert "[CMake][ELF] Add -fno-semantic-interposition and -Bsymbolic-functions"
This reverts commit 3bf1acab5b.

This is causing the test `gcov-shared-flush.c' to fail on the 2-stage
aarch64 buildbots (https://lab.llvm.org/buildbot/#/builders/7/builds/2720).
2021-05-13 14:31:17 +01:00
Shoaib Meenai 77997f28d5 [cmake] Fix typo in function name
Not sure how my local testing didn't trigger this path. Should fix
https://lab.llvm.org/buildbot/#/builders/132/builds/5494
2021-05-12 12:14:52 -07:00
Shoaib Meenai 56f7e5a822 [cmake] Add support for multiple distributions
LLVM's build system contains support for configuring a distribution, but
it can often be useful to be able to configure multiple distributions
(e.g. if you want separate distributions for the tools and the
libraries). Add this support to the build system, along with
documentation and usage examples.

Reviewed By: phosek

Differential Revision: https://reviews.llvm.org/D89177
2021-05-12 11:13:18 -07:00
Fangrui Song 3bf1acab5b [CMake][ELF] Add -fno-semantic-interposition and -Bsymbolic-functions
llvm-dev message: https://lists.llvm.org/pipermail/llvm-dev/2021-May/150465.html

In an ELF shared object, a default visibility defined symbol is preemptible by default.
This creates some missed optimization opportunities. -fno-semantic-interposition can optimize -fPIC:

* in Clang: avoid GOT/PLT cost for variable access/function calls to external linkage definition in the same TU
* in GCC: enable interprocedural optimizations (including inlining) and avoid PLT

See https://gist.github.com/MaskRay/2d4dfcfc897341163f734afb59f689c6 for more information.

-Bsymbolic-functions is more aggressive than -fvisibility-inlines-hidden (present since 2012) as it applies
to all function definitions.  It can

* avoid PLT for cross-TU function calls && reduce dynamic symbol lookup
* reduce dynamic symbol lookup for taking function addresses and optimize out GOT/TOC on x86-64/ppc64

With both options, the libLLVM.so and libclang-cpp.so performance should
be closer to PIE binary linking against `libLLVM*.a` and `libclang*.a`

(In a -DLLVM_TARGETS_TO_BUILD=X86 build, the number of JUMP_SLOT decreases from 12716 to 1628, and the number of GLOB_DAT decreases from 1918 to 1313
The built clang with `-DLLVM_LINK_LLVM_DYLIB=on -DCLANG_LINK_CLANG_DYLIB=on` is significantly faster.
See the Linux kernel build result https://bugs.archlinux.org/task/70697
)

Some implication:

Interposing a subset of functions is no longer supported.
(This is fragile anyway and cannot really be supported. For Mach-O we don't use
`ld -interpose`, so interposition is not supported on Mach-O at all.)

Compiling a program which takes the address of any LLVM function with
`{gcc,clang} -fno-pic` and expects the address to equal to the address taken
from libLLVM.so or libclang-cpp.so is unsupported. I am fairly confident that
llvm-project shouldn't have different behaviors depending on such pointer
equality (as we've been using -fvisibility-inlines-hidden which applies to
inline functions for a long time), but if we accidentally do, users should be
aware that they should not make assumption on pointer equality in `-fno-pic`
mode.

Reviewed By: phosek

Differential Revision: https://reviews.llvm.org/D102090
2021-05-12 10:34:31 -07:00
Dave Lee f44c6f20f5 [cmake] Enable -Wmisleading-indentation
Enable `-Wmisleading-indentation` to balance with the LLVM style of optional parentheses.

Differential Revision: https://reviews.llvm.org/D102092
2021-05-10 09:56:04 -07:00
Martin Storsjö b11a2f2544 [cmake] Use -ffunction-sections and -Wl,--gc-sections on MinGW targets
If compiling with GCC or linking with ld.bfd, these options have little
effect, but if built with Clang and linked with LLD, they provide a
quite notable size decrease - this shrinks an entire llvm-mingw
distribution package by 22%.

If building with BUILD_SHARED_LIBS or LLVM_BUILD_LLVM_DYLIB with LLD,
this requires a version of LLD that contains a fix for auto exporting
symbols from comdats, 2b01a417d7.

Differential Revision: https://reviews.llvm.org/D101568
2021-04-30 10:53:40 +03:00
Jim Radford e8b3a97ff7 [CMake][llvm] add missing include to LLVMCheckLinkerFlag
Differential Revision: https://reviews.llvm.org/D101417
2021-04-27 18:48:52 -07:00
Jim Radford 06d06f2f64 [CMake][llvm] avoid conflict w/ (and use when available) new builtin check_linker_flag
Match the API for the new check_linker_flag and use it directly when
available, leaving the old code as a fallback.

Differential Revision: https://reviews.llvm.org/D100901
2021-04-27 16:41:28 -07:00
Hubert Tong bdc4ec04d4 [AIX] Avoid use of mtim.tv_nsec member of stat structure on AIX
The value observed for the `mtim.tv_nsec` member is erroneous in some
AIX environments. Avoid using this member by forcing
`HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC` to `0`.

This resolves "mtime changed" errors such as the one
http://lab.llvm.org:8014/#/builders/126/builds/330/steps/5/logs/FAIL__Clang__test_c
has.

Reviewed By: daltenty, jsji

Differential Revision: https://reviews.llvm.org/D101323
2021-04-26 18:30:13 -04:00
Jim Radford 16a0d80912 [CMake][llvm] avoid changing global flags (may be used outside of llvm)
Changing global flags can break builds of projects that include/build
llvm as a sub-project, as the effect is global. Ideally we would
disable this warning at the directory level instead, but the obvious
way (disabling warning D9025) isn't supported. At least we can limit
the effect to only MSVC.

Patch by Jim Radford.

Differential Revision: https://reviews.llvm.org/D100900
2021-04-20 16:06:25 -07:00
Mircea Trofin f34ef248d3 [mlgo] Skip AOT-compiling a model if a header/object pair is provided
This allows one to cross-compile the header/object for a model in a
setup where the compiler is built on a system that cannot host the AOT
compiler. For example, if arm-hostable clang is desired, while the AOT
Tensorflow compiler can cross-compile to arm, it can't currently run on
arm.

The only alternative in that scenario would be to cross-compile clang
itself, but that gets complicated when trying to run tests after that.

Differential Revision: https://reviews.llvm.org/D99992
2021-04-13 09:46:29 -07:00
Kirill Bobyrev f37ea62e57 [CMake] try creating symlink first on windows
//-E create_symlink//  is available on windows since CMake 3.13 (LLVM now uses 3.13.4)
It may needs administrator privileges or enabled developer mode (Windows 10)
See https://cmake.org/cmake/help/latest/release/3.13.html

Reviewed By: kbobyrev

Differential Revision: https://reviews.llvm.org/D99170
2021-04-07 11:23:10 +02:00
Tom Stellard e07e08f366 Revert "llvm-shlib: Create object libraries for each component and link against them"
This reverts commit 43ceb74eb1.

This caused some build failures: https://bugs.llvm.org/show_bug.cgi?id=49818
2021-04-05 10:46:19 -07:00
Tom Stellard 43ceb74eb1 llvm-shlib: Create object libraries for each component and link against them
This makes it possible to build libLLVM.so without first creating a
static library for each component.  In the case where only libLLVM.so is
built (i.e. ninja LLVM) this eliminates 150 linker jobs.

Reviewed By: stellaraccident

Differential Revision: https://reviews.llvm.org/D95727
2021-04-01 14:58:44 -07:00
Petr Hosek 188592ff08 Revert "[CMake] Use write_basic_package_version_file for LLVM"
This reverts commit 3001d080c8 which
seems to have introduced a race condition that's failing the build
in some cases.
2021-03-29 13:07:39 -07:00
Alex Reinking 3001d080c8 [CMake] Use write_basic_package_version_file for LLVM
Use the CMake 3.13 features of CMakeConfigPackageHelpers to generate
LLVMConfigVersion.cmake with proper architecture detection, major+minor
version matching, etc.

Differential Revision: https://reviews.llvm.org/D99451
2021-03-27 21:02:20 +00:00
Aleksandr Platonov 203b072dd2 [CMake][gRPC] Fix a typo in protobuf version variable name
Without this patch CMake log contains `Using protobuf` instead of `Using protobuf <version>`.

Reviewed By: kbobyrev

Differential Revision: https://reviews.llvm.org/D99405
2021-03-26 19:33:06 +03:00
Vladislav Vinogradov 94470777af [CMAKE] Fix cross-compilation build
Call `get_errc_messages` only if `LLVM_INCLUDE_TESTS` was set.

Reviewed By: zero9178, abhina.sreeskantharajan, jhenderson

Differential Revision: https://reviews.llvm.org/D98861
2021-03-23 13:24:08 +03:00
Martin Storsjö c027553d95 [cmake] Disable GCC 9's -Wpessimizing-move
Similar to the existing code for disabling GCC's -Wredudant-move,
also check for the -Wpessimizing-move option and disable it if
possible.

This silences another bunch of noisy warnings when building LLVM
with GCC 9.

As noted for -Wredundant-move, the code can't be fixed to silence the
warnings while retaining support for older compilers.

Differential Revision: https://reviews.llvm.org/D98942
2021-03-22 15:14:46 +02:00
Jinsong Ji 14696baaf4 [AIX] Update rpath for BUILD_SHARED_LIBS
BUILD_SHARED_LIBS build llvm component as shared library,
which can reduce the size a lot.

Normally, the binary use ORIGIN../lib to load component libraries,
unfortunatly, ORIGIN is not supported by AIX ld.

We hardcoded the build lib and install lib path in rpath for now
to enable BUILD_SHARED_LIBS build.

Understand that this is not perfect solution,
we can update this when we find better solution.

Reviewed By: hubert.reinterpretcast

Differential Revision: https://reviews.llvm.org/D98901
2021-03-20 20:31:43 +00:00
Martin Storsjö cfa65f77cb [cmake] Enable Clang warnings about redundant semicolons
This matches what GCC warns about when -pedantic is enabled.

This should avoid such redundant semicolons creeping into the codebase.

Differential Revision: https://reviews.llvm.org/D98941
2021-03-19 18:49:05 +02:00
Markus Böck 3d0aed7936 [CMake] Use compiler-rt location instead of resource directory to find clang-cls runtime directory
The current cmake script attempts to add the path containing clangs various runtime systems by getting the resource directory and then appending the hardcoded value /lib/windows to it. This works for a normal clang-cl build but fails for a build of clang using LLVM_ENABLE_PER_TARGET_RUNTIME_DIR, such as the builds from llvm/runtimes.

This patch instead uses -print-libgcc-file-name in conjunction with --rtlib=compiler-rt, and instead adds the containing directory as library path.

For non per-target runtime directory builds, such as the release builds, there is no change. Even if the builtins library were to be deleted or moved it would output the same path as before.
For per-target runtime builds that also have the builtins library, this now finds the correct directory containing all of clang runtime libraries.

Only case still not handled by this change, is if a per-target runtime directory build is used, but the builtins library was not built.
I believe that is the best we can do for now however, without modifying clang.

Differential Revision: https://reviews.llvm.org/D98786
2021-03-18 09:24:49 +01:00
Markus Böck 953bb5e5c8 [test] Make sure the test program in GetErrcMessages.cmake exits normally.
If for some reason the test program does not exit normally it'd currently lead to a false positive and it's stdout output being assigned to the output variable.

Instead, check the test program exited normally before assigning the process output to the out variable.

Follow up on rGaf2796c76d2ff4b73165ed47959afd35a769beee
Fixes an issue discovered post commit in https://reviews.llvm.org/D98278
2021-03-16 12:22:40 +01:00
Markus Böck 4a17ac0387 [test][NFC] Minor formatting and comment adjustments in GetErrcMessages.cmake
These changes address post-commit review comments discussed in https://reviews.llvm.org/D98278
2021-03-16 11:08:57 +01:00
Kirill Bobyrev 9bcf0eff99
[clangd] Optionally add reflection for clangd-index-server
This was originally landed without the optional part and reverted later:

8080ea4c4b

Reviewed By: kadircet

Differential Revision: https://reviews.llvm.org/D98404
2021-03-15 21:07:25 +01:00
Markus Böck af2796c76d [test] Add ability to get error messages from CMake for errc substitution
Visual Studios implementation of the C++ Standard Library does not use strerror to produce a message for std::error_code unlike other standard libraries such as libstdc++ or libc++ that might be used.

This patch adds a cmake script that through running a C++ program gets the error messages for the POSIX error codes and passes them onto lit through an optional config parameter.

If the config parameter is not set, or getting the messages failed, due to say a cross compiling configuration without an emulator, it will fall back to using pythons strerror functions.

Differential Revision: https://reviews.llvm.org/D98278
2021-03-15 20:56:08 +01:00
Christopher Tetreault 39970764af [CMake] Require python 3.6 if enabling LLVM test targets
The lit test suite uses python 3.6 features. Rather than a strange
python syntax error upon running the lit tests, we will require the
correct version in CMake.

Reviewed By: serge-sans-paille, yln

Differential Revision: https://reviews.llvm.org/D95635
2021-03-15 09:50:39 -07:00
Dave Lee 683e89722a Revert "[cmake] Enable -Werror=return-type"
This reverts commit ce94a16165.
2021-03-10 14:47:08 -08:00
Kadir Cetinkaya 99b01cf28d
Revert "[clangd] Enable reflection for clangd-index-server"
This reverts commit 8080ea4c4b.

As discussed offline we should only do that for debug builds.
2021-03-10 14:12:37 +01:00
Kirill Bobyrev 8080ea4c4b [clangd] Enable reflection for clangd-index-server
This allows sending requests through CLI and more debugging
opportunities. Example:

```bash
$ grpc_cli ls localhost:50051
clang.clangd.remote.v1.SymbolIndex
grpc.reflection.v1alpha.ServerReflection
grpc.health.v1.Health
```
2021-03-10 09:07:39 +01:00
Dave Lee ce94a16165 [cmake] Enable -Werror=return-type
Turn `-Wreturn-type` into an error.

This is currently used by libcxx, libcxxabi, and libunwind, and would be a good default
for all of llvm. I'm not aware of any cases where this shouldn't be an error. This
ensures different build configs, merges, and downstream branches catch issues sooner.

Differential Revision: https://reviews.llvm.org/D98224
2021-03-09 13:51:09 -08:00
Min-Yih Hsu bec7b16692 [M68k](3/8) Skeleton and target description files
- Infrastructure for the target (i.e. build files, target triple etc.)
 - All of the target description TableGen file

Authors: myhsu, m4yers, glaubitz

Differential Revision: https://reviews.llvm.org/D88389
2021-03-08 12:30:57 -08:00
Raul Tambre 10a7289649 [runtimes] Fix crosscompiling after a7cad6680b (D97451)
It moved the logic for CMake target arguments into llvm_ExternalProject_Add().
No handling was added for CMAKE_CROSSCOMPILING, which has a separate set of compiler_args.
This broke crosscompiling, as now the runtimes builds defaulted to the compiler's default.

I've also added passing of CMAKE_ASM_COMPILER, which was missing before although we were passing the triple for it.

Reviewed By: zero9178

Differential Revision: https://reviews.llvm.org/D97855
2021-03-06 11:35:14 +02:00
Xiangling Liao e9f9ec837d [CMake][AIX] Adjust plugin library extension used on AIX
As stated in the CMake manual, we are supposed to use MODULE rules to generate
plugin libraries:

"MODULE libraries are plugins that are not linked into other targets but may be
loaded dynamically at runtime using dlopen-like functionality"

Besides, LLVM's plugin infrastructure fits with the AIX treatment of .so
shared objects more than it fits with the AIX treatment of .a library archives
(which may contain shared objects).

Differential revision: https://reviews.llvm.org/D96282
2021-03-04 11:23:06 -05:00
Markus Böck a7cad6680b [PR48898][CMake] Support MinGW Toolchain tool sin llvm_ExternalProject_Add
Windows is in the unique position of having two drivers, clang-cl and normal GNU clang, depending on whether a GNU or MSVC target is used. The current implementation with the USE_TOOLCHAIN argument assumes that when CMAKE_SYSTEM_NAME is set to Windows that clang-cl should be used, which is the incorrect choice when targeting a GNU environment.

This patch solves this problem by adding an optional TARGET_TRIPLE argument to llvm_ExternalProject_Add, which sets the various CMAKE_<LANG>_COMPILER_TARGET variables. Additionally, if the triple is detected as an MSVC environment, clang-cl and similar MSVC specific tools will be used instead of the GNU tools.
2021-03-02 22:45:05 +01:00
Arthur Eubanks e765324d89 [CMake] Don't optimize tests so much under ThinLTO
This drops check-llvm under -DLLVM_ENABLE_LTO=Thin from 13m to 10m20s on Windows and 20m to 15m35s on Linux.

Reviewed By: hans

Differential Revision: https://reviews.llvm.org/D96618
2021-02-22 15:13:49 -08:00
Alex Hoppen 55d8f0d03b [cmake] Move check for libproc to config-ix.cmake
As suggested by Nico in https://reviews.llvm.org/D96049, move check for libproc
from CMakeLists to config-ix.cmake

Reviewed By: thakis

Differential Revision: https://reviews.llvm.org/D96713

Note: Also removes the CMAKE_REQUIRED_LIBRARIES which doesn't appear to
be necessary.
2021-02-18 10:54:27 +01:00
Nico Weber 44ea794cf9 build: Add LLVM_WINSYSROOT to make setting /winsysroot easy on Win
Also add a script for sysroot management. For now, it can only create
fake sysroots that just symlink to local folders. This is useful for
testing.

Differential Revision: https://reviews.llvm.org/D96868
2021-02-17 10:27:25 -05:00
Mircea Trofin 33481c9997 [mlgo] Fetch models from path / URL
Allow custom location for pre-trained models used when AOT-compiling
policies.

Differential Revision: https://reviews.llvm.org/D96796
2021-02-16 22:47:14 -08:00
Stella Stamenova ed98676fa4 Support multi-configuration generators correctly in several config files
Multi-configuration generators (such as Visual Studio and Xcode) allow the specification of a build flavor at build time instead of config time, so the lit configuration files need to support that - and they do for the most part. There are several places that had one of two issues (or both!):

1) Paths had %(build_mode)s set up, but then not configured, resulting in values that would not work correctly e.g. D:/llvm-build/%(build_mode)s/bin/dsymutil.exe
2) Paths did not have %(build_mode)s set up, but instead contained $(Configuration) (which is the value for Visual Studio at configuration time, for Xcode they would have had the equivalent) e.g. "D:/llvm-build/$(Configuration)/lib".

This seems to indicate that we still have a lot of fragility in the configurations, but also that a number of these paths are never used (at least on Windows) since the errors appear to have been there a while.

This patch fixes the configurations and it has been tested with Ninja and Visual Studio to generate the correct paths. We should consider removing some of these settings altogether.

Reviewed By: JDevlieghere, mehdi_amini

Differential Revision: https://reviews.llvm.org/D96427
2021-02-11 09:32:20 -08:00
Tom Stellard 997f6b6f8e [CMake] Remove some dead code in llvm_install_library_symlink()
Reviewed By: smeenai

Differential Revision: https://reviews.llvm.org/D95666
2021-02-10 10:13:04 -08:00
Ta-Wei Tu e89fcbfad6 Fix deprecated usage of `mallinfo`
glibc deprecates `mallinfo` in the latest version of 2.33. This patch replaces the usage of `mallinfo` with the new `mallinfo2` when it's available.

Reviewed By: lattner

Differential Revision: https://reviews.llvm.org/D96359
2021-02-10 13:53:57 +08:00
Markus Böck 99dfcfd14c [CMake] [MinGW] Enable use of LLVM_USE_SANITIZER in a MinGW environment
Currently using LLVM_USE_SANITIZER with a MinGW target leads to a fatal
configuration error due to an unsupported platform. MinGW targets on
clang however implement a few sanitizers, currently ASAN and UBSAN.

This patch enables LLVM_USE_SANITIZER in a MinGW environment as well.

Differential Revision: https://reviews.llvm.org/D95750
2021-02-08 23:04:50 +02:00
Mehdi Amini bb0212929e Fix CMake LLVM_TARGETS_TO_BUILD "Native" option to work with JIT
LLVM_TARGETS_TO_BUILD accepts both "host" or "Native" for auto-selecting
the target from the environment. However the way "Native" was plumbed
would lead to the JIT environment being disabled. This patch is making
"Native" works just as "host".

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D95837
2021-02-02 18:47:15 +00:00
Raphael Isemann e7bc6c594b Reland [lldb][docs] Use sphinx instead of epydoc to generate LLDB's Python reference
The build server should now have the missing dependencies.

Original summary:

Currently LLDB uses epydoc to generate the Python API reference for the website.
epydoc however is unmaintained since more than a decade and no longer works with
Python 3. Also whatever setup we had once for generating the documentation on
the website server no longer seems to work, so the current website documentation
has been stale since more than a year.

This patch replaces epydoc with sphinx and its automodapi plugin that can
generate Python API references. LLVM already uses sphinx for the rest of the
documentation, so this way we are more consistent with the rest of LLVM. The
only new dependency is the automodapi plugin for sphinx.

This patch effectively does the following things:
* Remove the epydoc code.
* Make a new dummy Python API page in our website that just calls the Sphinx
  command for generated the API documentation.
* Add a mock _lldb module that is only used when generating the Python API.
 This way we don't have to build all of LLDB to generate the API reference.

Some notes:
* The long list of skips is necessary due to boilerplate functions that SWIG
  is generating. Sadly automodapi is not really scriptable from what I can see,
  so we have to blacklist this stuff manually.
* The .gitignore change because automodapi wants a subfolder of our
  documentation directory to place generated documentation files there. The path
  is also what is used on the website, so we can't really workaround this
  (without copying the whole `docs` dir somewhere else when we build).
* We have to use environment variables to pass our build path to our sphinx
  configuration. Sphinx doesn't support passing variables onto that script.

Reviewed By: JDevlieghere

Differential Revision: https://reviews.llvm.org/D94489
2021-01-17 12:13:01 +01:00
Raphael Isemann 9d2053f61a Revert "[lldb][docs] Use sphinx instead of epydoc to generate LLDB's Python reference"
This reverts commit bab121a1b6. It seems the
docs buildbot doesn't have the required Python headers.
2021-01-15 14:07:45 +01:00
Raphael Isemann bab121a1b6 [lldb][docs] Use sphinx instead of epydoc to generate LLDB's Python reference
Currently LLDB uses epydoc to generate the Python API reference for the website.
epydoc however is unmaintained since more than a decade and no longer works with
Python 3. Also whatever setup we had once for generating the documentation on
the website server no longer seems to work, so the current website documentation
has been stale since more than a year.

This patch replaces epydoc with sphinx and its automodapi plugin that can
generate Python API references. LLVM already uses sphinx for the rest of the
documentation, so this way we are more consistent with the rest of LLVM. The
only new dependency is the automodapi plugin for sphinx.

This patch effectively does the following things:
* Remove the epydoc code.
* Make a new dummy Python API page in our website that just calls the Sphinx
  command for generated the API documentation.
* Add a mock _lldb module that is only used when generating the Python API.
 This way we don't have to build all of LLDB to generate the API reference.

Some notes:
* The long list of skips is necessary due to boilerplate functions that SWIG
  is generating. Sadly automodapi is not really scriptable from what I can see,
  so we have to blacklist this stuff manually.
* The .gitignore change because automodapi wants a subfolder of our
  documentation directory to place generated documentation files there. The path
  is also what is used on the website, so we can't really workaround this
  (without copying the whole `docs` dir somewhere else when we build).
* We have to use environment variables to pass our build path to our sphinx
  configuration. Sphinx doesn't support passing variables onto that script.

Reviewed By: JDevlieghere

Differential Revision: https://reviews.llvm.org/D94489
2021-01-15 13:26:42 +01:00
Raul Tambre 840a2c9783 [CMake] Fix incorrect rpath for tests if LLVM_LOCAL_RPATH isn't set
d9ce31ae7d (D94322) removed the check because I thought it was dead
due to checking the existance of a variable (which always existed).

This causes LLDB tests to fail as they set NO_INSTALL_RPATH because
they're never meant to be installed, but we still would end up using
the install rpath.

Add the check back and make it explicitly check for an empty value
to make the purpose clearer and avoid implicit test for a false/true
value.

Differential Revision: https://reviews.llvm.org/D94326
2021-01-08 21:24:18 +02:00