maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[docs] Added solutions to slow build under common problems. 

I added a list of options to configure should someone have issues with
long build time or running out of memory. This was added under common
problems in the getting started section of the documentation.

Reviewed By: Meinersbur, dim, e-leclercq

Differential Revision: https://reviews.llvm.org/D75425
This commit is contained in:
Evan LeClercq 2020-03-28 04:09:58 -05:00 committed by Michael Kruse
parent 65b4695375
commit 37943e518c
1 changed files with 55 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

55
llvm/docs/GettingStarted.rst
View File

@ -1095,6 +1095,61 @@ If you are having problems building or using LLVM, or if you have any other
general questions about LLVM, please consult the `Frequently Asked
Questions <FAQ.html>`_ page.
If you are having problems with limited memory and build time, please try
building with ninja instead of make. Please consider configuring the
following options with cmake:
* -G Ninja
Setting this option will allow you to build with ninja instead of make.
Building with ninja significantly improves your build time, especially with
incremental builds, and improves your memory usage.
* -DLLVM_USE_LINKER
Setting this option to either gold or lld will significantly improve
performance. In the case that you are compiling lld, you may wish to use the
gold linker as a faster alternative.
* -DCMAKE_BUILD_TYPE
This option defaults to Debug; however, this may consume more memory during
the linking phase. So, you may wish to use the build type Release. Another
build type you may wish to consider is release-with-asserts which compiles at
nearly the same rate as the Release build; however, it may not be as easy
to debug. MinSizeRel is another build type you may wish to consider, if you
are still having problems with slow build time.
* -DLLVM_PARALLEL_LINK_JOBS
Set this equal to number of jobs you wish to run simultaneously. This is
similar to the -j option used with make, but only for link jobs. This option
is of course only meaningful if you plan to build with ninja. You may wish to
use a very low number of jobs, as this will greatly reduce the amount memory
used during the build process. If you have limited memory, you may wish to
set this to 1.
* -DLLVM_TARGETS_TO_BUILD
Set this equal to the target you wish to build. You may wish to set this to
X86; however, you will find a full list of targets within the
llvm-project/llvm/lib/Target directory.
* -DLLVM_OPTIMIZED_TABLEGEN
Set this to ON to generate a fully optimized tablegen during build. This will
significantly improve your build time.
* -DLLVM_ENABLE_PROJECTS
Set this equal to the projects you wish to compile (e.g. clang, lld, etc.) If
compiling more than one project, deliniate the list with a semicolon. Should
you run into issues with the semicolon, try surrounding it with single quotes.
* -DCLANG_ENABLE_STATIC_ANALYZER
Set this option to OFF if you do not require the clang static analyzer. This
should improve your build time significantly.
* -DLLVM_USE_SPLIT_DWARF
Consider setting this to ON if you require a debug build, as this will ease
memory pressure on the linker. This will make linking much faster, as the
binaries will not contain any of the debug information; however, this will
generate the debug information in the form of a DWARF object file (with the
extension .dwo).
.. _links:
Links