libclang is only built as static library in the GN build at the
moment, which means we now generate a .exports file form a version
script and then link.exe and ld64 inputs from the .exports file
but don't use the version script, but hey.
Apparently ubsan errors are non-fatal by default. If you introduce UB
into LLVM and run the tests, if errors are not fatal, the test will
still produce the expected output and the tests will pass. In order to
make ubsan errors show up as test failures, they have to be made fatal.
Pass the -fno-sanitize-recover=all flag to make it so.
Differential Revision: https://reviews.llvm.org/D103298
Avoids a warning from the linker. The user still has to put the resource
directory on the linker search path, and I can't find a clean way to do
that automatically in gn.
- D96404 defaulted to libunwind which isn't provided by NDK r21
(or r22), so specify -rtlib=libgcc on non-arm32.
- D97993 means that we need to use --gcc-toolchain instead of -B
to let the driver find libgcc.
With this, you can set `clang_base_path = "//out/gn1"` in `out/gn2/args.gn` and
the build in out/gn2 will use clang and lld from out/gn1.
Setting `clang_base_path` to an absolute path (with e.g.
`clang_base_path = getenv("HOME") + "/src/..."`) should behave as before.
Differential Revision: https://reviews.llvm.org/D97989
The new Darwin backend for LLD is now able to link reasonably large
real-world programs on x86_64. For instance, we have achieved
self-hosting for the X86_64 target, where all LLD tests pass when
building lld with itself on macOS. As such, we would like to make it the
default back-end.
The new port is now named `ld64.lld`, and the old port remains
accessible as `ld64.lld.darwinold`
This [annoucement email][1] has some context. (But note that, unlike
what the email says, we are no longer doing this as part of the LLVM 12
branch cut -- instead we will go into LLVM 13.)
Numerous mechanical test changes were required to make this change; in
the interest of creating something that's reviewable on Phabricator,
I've split out the boring changes into a separate diff (D95905). I plan to
merge its contents with those in this diff before landing.
(@gkm made the original draft of this diff, and he has agreed to let me
take over.)
[1]: https://lists.llvm.org/pipermail/llvm-dev/2021-January/147665.html
Reviewed By: #lld-macho, thakis
Differential Revision: https://reviews.llvm.org/D95204
This is a tiny bit messy because compiler-rt needs different sysroots for
macOS, iOS, etc. We want sysroot.py to create something that is a hermetic
representation of all build deps, so it needs to create a directory that
contains all needed SDKs, and these subdirectories are then passed to
cmake which passes each of these _subdirectories_ as different -isysroot
flags while building the runtime libraries.
Differential Revision: https://reviews.llvm.org/D96958
CMAKE_SYSROOT works fine here, and `sysroot.py make-fake`
borders on trivial here, but I suppose it's still nice
to have a consistent script to set these up across platforms.
And these are the platforms where we can do real sysroot management one
day.
Differential Revision: https://reviews.llvm.org/D96882
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
use_lld defaults to true on non-mac if clang_base_path is set (i.e.
the host compiler is a locally-built clang). On mac, the lld Mach-O
port used to be unusable, but ld64.lld.darwinnew is close to usable.
When explicitly setting `use_lld = true` in a GN build on a mac host,
check-lld passes, two check-clang tests fail, and a handful check-llvm
tests fail (the latter all due to -flat_namespace not yet being implemented).
This will hopefully fix the build not becoming clean when using Ninja
1.9+. Ninja 1.9 enabled high-resolution time stamps, but pax doesn't
correctly set high-resolution timestamps on its output.
See https://github.com/nico/hack/blob/master/notes/copydir.md for a
detailed writeup of problem and alternatives.
For full-debug-info (is_debug=true / symbol_level=2 builds), this makes
linking 15% slower, but gdb startup 1500% faster (for lld: link time
3.9s->4.4s, gdb load time >30s->2s).
For link time, I ran
bench.py -o {noindex,index}.txt \
sh -c 'rm out/gn/bin/lld && ninja -C out/gn lld'
and then `ministat noindex.txt index.txt`:
```
x noindex.txt
+ index.txt
N Min Max Median Avg Stddev
x 5 3.784461 4.0200169 3.8452811 3.8754988 0.089902595
+ 5 4.32496 4.6058481 4.3361208 4.4141198 0.12288267
Difference at 95.0% confidence
0.538621 +/- 0.15702
13.8981% +/- 4.05161%
(Student's t, pooled s = 0.107663)
```
For gdb load time I loaded the crash in PR48392 with
gdb -ex r --args ../out/gn/bin/ld64.lld.darwinnew @response.txt
and just stopped the time until the crash got displayed with a stopwatch
a few times. So the speedup there is less precise, but it's so
pronounced that that's ok (loads ~instantly with the patch, takes a very
long time without it).
Only doing this for LLD because I haven't tried it with other linkers.
Differential Revision: https://reviews.llvm.org/D92844
is_debug by default makes symbol_level = 2 and !is_debug means by
default symbol_level = 0.
Reviewed By: thakis
Differential Revision: https://reviews.llvm.org/D92958
llvm-config output with the gn build is just good enough to make
tests pass, but llvm-config wants all .a files it knows about to
actually exist. So let it know about fewer .a files that don't
exist if not all targets are enabled.
It's built with just-built clang, like all other compiler-rt parts
in the GN build.
This requires adding some cross build support to the mac toolchain.
Also add explicit mmacosx-version-min and miphoneos-version-min
flags to the build.
ios.a is only built with the arm64 slice, iossim.a only with the
x86_64 slice for now. (The latter should maybe become host_cpu
when Arm Macs become a common iOS development platform.)
With this, it's possible to build chromium/iOS with a GN-built LLVM.
Differential Revision: https://reviews.llvm.org/D89260
As of GN 3028c6a426a4, the hack that transformed "libs" ending in
".framework" from -l arguments to -framework arguments has been removed.
Instead, "frameworks" must be used, and the toolchain must provide
support.
Differential Revision: https://reviews.llvm.org/D84219
Peter Collingbourne