diff options
author | John Ericson <John.Ericson@Obsidian.Systems> | 2021-04-28 22:36:47 +0000 |
---|---|---|
committer | John Ericson <John.Ericson@Obsidian.Systems> | 2021-07-13 15:21:41 +0000 |
commit | 1e03c37b97b6176a60404d84665c40321f4e33a4 (patch) | |
tree | b91be8340dfdc15c8c559d3f765ed05a0a8021d3 /libunwind/docs | |
parent | fb44c3223e0c36e969762dd182b4992061b455d3 (diff) | |
download | llvm-1e03c37b97b6176a60404d84665c40321f4e33a4.zip llvm-1e03c37b97b6176a60404d84665c40321f4e33a4.tar.gz llvm-1e03c37b97b6176a60404d84665c40321f4e33a4.tar.bz2 |
Prepare Compiler-RT for GnuInstallDirs, matching libcxx, document all
This is a second attempt at D101497, which landed as
9a9bc76c0eb72f0f2732c729a460abbd5239c2e3 but had to be reverted in
8cf7ddbdd4e5af966a369e170c73250f2e3920e7.
This issue was that in the case that `COMPILER_RT_INSTALL_PATH` is
empty, expressions like "${COMPILER_RT_INSTALL_PATH}/bin" evaluated to
"/bin" not "bin" as intended and as was originally.
One solution is to make `COMPILER_RT_INSTALL_PATH` always non-empty,
defaulting it to `CMAKE_INSTALL_PREFIX`. D99636 adopted that approach.
But, I think it is more ergonomic to allow those project-specific paths
to be relative the global ones. Also, making install paths absolute by
default inhibits the proper behavior of functions like
`GNUInstallDirs_get_absolute_install_dir` which make relative install
paths absolute in a more complicated way.
Given all this, I will define a function like the one asked for in
https://gitlab.kitware.com/cmake/cmake/-/issues/19568 (and needed for a
similar use-case).
---
Original message:
Instead of using `COMPILER_RT_INSTALL_PATH` through the CMake for
complier-rt, just use it to define variables for the subdirs which
themselves are used.
This preserves compatibility, but later on we might consider getting rid
of `COMPILER_RT_INSTALL_PATH` and just changing the defaults for the
subdir variables directly.
---
There was a seaming bug where the (non-Apple) per-target libdir was
`${target}` not `lib/${target}`. I suspect that has to do with the docs
on `COMPILER_RT_INSTALL_PATH` saying was the library dir when that's no
longer true, so I just went ahead and fixed it, allowing me to define
fewer and more sensible variables.
That last part should be the only behavior changes; everything else
should be a pure refactoring.
---
I added some documentation of these variables too. In particular, I
wanted to highlight the gotcha where `-DSomeCachePath=...` without the
`:PATH` will lead CMake to make the path absolute. See [1] for
discussion of the problem, and [2] for the brief official documentation
they added as a result.
[1]: https://cmake.org/pipermail/cmake/2015-March/060204.html
[2]: https://cmake.org/cmake/help/latest/manual/cmake.1.html#options
In 38b2dec37ee735d5409148e71ecba278caf0f969 the problem was somewhat
misidentified and so `:STRING` was used, but `:PATH` is better as it
sets the correct type from the get-go.
---
D99484 is the main thrust of the `GnuInstallDirs` work. Once this lands,
it should be feasible to follow both of these up with a simple patch for
compiler-rt analogous to the one for libcxx.
Reviewed By: phosek, #libc_abi, #libunwind
Differential Revision: https://reviews.llvm.org/D105765
Diffstat (limited to 'libunwind/docs')
-rw-r--r-- | libunwind/docs/BuildingLibunwind.rst | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/libunwind/docs/BuildingLibunwind.rst b/libunwind/docs/BuildingLibunwind.rst index ad9dee0..9b11042 100644 --- a/libunwind/docs/BuildingLibunwind.rst +++ b/libunwind/docs/BuildingLibunwind.rst @@ -159,3 +159,10 @@ libunwind specific options .. option:: LIBUNWIND_SYSROOT Sysroot for cross compiling + +.. option:: LIBUNWIND_INSTALL_LIBRARY_DIR:PATH + + **Default**: ``lib${LIBUNWIND_LIBDIR_SUFFIX}`` + + Path where built libunwind libraries should be installed. If a relative path, + relative to ``CMAKE_INSTALL_PREFIX``. |