11 Commits

Author SHA1 Message Date
Martin Storsjö
4cda8e6267 [docs] Rewrite/improve the docs for LLVM_NATIVE_TOOL_DIR
Don't include it among the mandatory options; the automatically built
tools via a nested cmake build work fine these days
(in particular, since 93010544a813dfbfa64dd7cee68785f572f974d1 /
https://reviews.llvm.org/D126313).

Clarify the directory path-to-host-bin into something more verbose,
to avoid ambiguity with LLVM_HOST_TRIPLE.

Differential Revision: https://reviews.llvm.org/D142960
2023-02-03 10:55:33 +02:00
Martin Storsjö
cb19e3b20d [docs] Prefer setting LLVM_HOST_TRIPLE instead of LLVM_DEFAULT_TARGET_TRIPLE and LLVM_TARGET_ARCH
Setting LLVM_HOST_TRIPLE propagates the information to a few more
places than if only setting LLVM_TARGET_ARCH and
LLVM_DEFAULT_TARGET_TRIPLE, while both of those settings get their
defaults implied from LLVM_HOST_TRIPLE if they're not overridden.

Differential Revision: https://reviews.llvm.org/D142404
2023-02-03 10:54:29 +02:00
Martin Storsjö
95a2aeca3b [docs] Add/update docs regarding LLVM_NATIVE_TOOL_DIR vs LLVM_TABLEGEN
Differential Revision: https://reviews.llvm.org/D142349
2023-01-23 23:49:37 +02:00
Tobias Hieta
350bdf9227 [CMake] Make omitting CMAKE_BUILD_TYPE an error
After a lot of discussion in this diff the consensus was that it is really hard to guess the users intention with their LLVM build. Instead of trying to guess if Debug or Release is the correct default option we opted for just not specifying CMAKE_BUILD_TYPE a error.

Discussion on discourse here:
https://discourse.llvm.org/t/rfc-select-a-better-linker-by-default-or-warn-about-using-bfd

Reviewed By: hans, mehdi_amini, aaron.ballman, jhenderson, MaskRay, awarzynski

Differential Revision: https://reviews.llvm.org/D124153
2022-05-04 14:01:33 +02:00
fourdim
bc53ebbda8 [docs] HowToCrossCompileLLVM.rst: update cmake options
This patch updates the cmake options suggested when cross compiling. This should fix [#52819](https://github.com/llvm/llvm-project/issues/52819).

Brad King (Member of CMake) says:

The linked [CMAKE_CROSSCOMPILING](https://cmake.org/cmake/help/v3.22/variable/CMAKE_CROSSCOMPILING.html) documentation says:

This variable will be set to true by CMake if the `CMAKE_SYSTEM_NAME` variable has been set manually (i.e. in a toolchain file or as a cache entry from the cmake command line).

It is not meant to be set by project code or toolchain files. It is always set automatically. Don't put `set(CMAKE_CROSSCOMPILING ON)` anywhere in your code.

`CMAKE_CROSSCOMPILING` indicates only whether `CMAKE_SYSTEM_NAME` was set by the user/project/toolchain-file instead of by CMake.

In LLVM project, `CMAKE_CROSSCOMPILING` is used to determine whether to execute some tests on the host machine.

LLVM needs to use another method for that. `CMAKE_CROSSCOMPILING` is not a reliable indicator of whether produced binaries will run on the host, and does not claim so in its documentation. If one sets `CMAKE_SYSTEM_NAME` to Linux in a toolchain file, and builds on a Linux host, that doesn't mean the target architecture or minimum glibc version is the same.

Reviewed By: rengolin

Differential Revision: https://reviews.llvm.org/D119804
2022-02-19 20:37:12 +08:00
Fangrui Song
d2cc23a337 [docs] HowToCrossCompileLLVM.rst: prefer --target= over legacy -target 2022-01-25 12:39:32 -08:00
Sylvestre Ledru
72fd1033ea Doc: Links should use https 2020-03-22 22:49:33 +01:00
Renato Golin
e01a94a6c5 [docs] Fix unexpected indentation in HowToCrossCompileLLVM.rst
Seems like my sphynx version is different than the one in the bot, as it
accepted everything locally. I think this is the right fix...

llvm-svn: 269062
2016-05-10 14:02:46 +00:00
Renato Golin
6617236572 [docs] Change CrossCompilation guidde to reflect changes in Clang/GCC
HowToCrossCompile was outdated and generating too much traffic on the mailing
list with similar queries. This change helps offset most of the problems that
were reported recently including:

 * Removing the -ccc-gcc-name, adding --sysroot
 * Making references to Debian's multiarch for target libraries
 * Expanding -DCMAKE_CXX_FLAGS for both GCC and Clang
 * Some formatting and clarifications in the text

llvm-svn: 269054
2016-05-10 12:54:12 +00:00
Sean Silva
23d2f6989e [docs] Some typographical fixes.
llvm-svn: 190324
2013-09-09 19:05:03 +00:00
Renato Golin
d24899bfc2 Cross-compilation doc
llvm-svn: 190282
2013-09-08 20:44:48 +00:00