The `freestanding` library is built with specific compiler flags to signify
that it is indeed freestanding code. That is, it does not depend on a
standard library.
One of the requirements of freestanding code is that the toolchain still
expects implementations of `memcpy`, `memmove`, `memcmp`, and `memset`.
I did briefly implement my own naive versions of these functions, but that
solution is less than ideal since the implementations must be `extern` and are
thus picked up by the entire `firefox.exe` binary. This denies the rest of
`firefox.exe` the benefit of optimized implementations. On Windows, the
sandbox is linked into `firefox.exe`, so we cannot just shrug and
assume that naive implementations will not have any effect on anything.
There are, however, optimized implementations of these functions that are
exported by `ntdll.dll`. They are not included in the `ntdll.lib` that is
included in the Windows SDK. Using `llvm-dlltool`, we can build an import
library containing the missing entries and then add that library to `OS_LIBS`.
Depends on D43156
Differential Revision: https://phabricator.services.mozilla.com/D43157
--HG--
extra : moz-landing-system : lando
An explanation of the Mozilla Source Code Directory Structure and links to
project pages with documentation can be found at:
https://developer.mozilla.org/en/Mozilla_Source_Code_Directory_Structure
For information on how to build Mozilla from the source code, see:
https://developer.mozilla.org/en/docs/Build_Documentation
To have your bug fix / feature added to Mozilla, you should create a patch and
submit it to Bugzilla (https://bugzilla.mozilla.org). Instructions are at:
https://developer.mozilla.org/en/docs/Creating_a_patch
https://developer.mozilla.org/en/docs/Getting_your_patch_in_the_tree
If you have a question about developing Mozilla, and can't find the solution
on https://developer.mozilla.org, you can try asking your question in a
mozilla.* Usenet group, or on IRC at irc.mozilla.org. [The Mozilla news groups
are accessible on Google Groups, or news.mozilla.org with a NNTP reader.]
Nightly development builds can be downloaded from:
https://archive.mozilla.org/pub/firefox/nightly/latest-mozilla-central/
- or -
https://www.mozilla.org/firefox/channel/desktop/#nightly
Keep in mind that nightly builds, which are used by Mozilla developers for
testing, may be buggy.