This statement is used as a hint for the compiler so that it knows that
the location where it's placed cannot be reached. It will mostly be used
after longjmp() or equivalent statements that deal with error processing
and that the compiler doesn't know will not return on certain conditions,
so that it doesn't complain about null dereferences on error paths.
An offsetof() macro was introduced with commit 928fbfa ("MINOR: compiler:
introduce offsetoff().") with a fallback for older compilers. But this
breaks gcc 3.4 because __size_t and __uintptr_t are not defined there.
However size_t and uintptr_t are, so let's fix it this way. No backport
needed.
While gcc only emits warnings about unused static functions, Clang also
emits such a warning when the functions are inlined. This is a bit
annoying at certain places where functions are provided to manipulate
multiple data types and are not yet used. Let's have a type modifier
"__maybe_unused" which sets the "unused" attribute like the Linux kernel
does. It's elegant as it allows the code author to indicate that it knows
that this element might be unused. It works on variables as well, which
is convenient to remove ifdefs around local variables in certain functions,
but doesn't work on labels.
After some tests, gcc 5.x produces better code with likely()
than without, contrary to gcc 4.x where it was better to disable
it. Let's re-enable it for 5 and above.
(from ebtree 6.0.6)
This version is mainly aimed at clarifying the fact that the ebtree license
is LGPL. Some files used to indicate LGPL and other ones GPL, while the goal
clearly is to have it LGPL. A LICENSE file has also been added.
No code is affected, but it's better to have the local tree in sync anyway.
(cherry picked from commit 24dc7cca051f081600fe8232f33e55ed30e88425)
It's a pain to enable regparm because ebtree is built in its corner
and does not depend on the rest of the config. This causes no problem
except that if the regparm settings are not exactly similar, then we
can get inconsistent function interfaces and crashes.
One solution realized in this patch consists in externalizing all
compiler settings and changing CONFIG_XXX_REGPARM into CONFIG_REGPARM
so that we ensure that any sub-component uses the same setting. Since
ebtree used a value here and not a boolean, haproxy's config has been
set to use a number too. Both haproxy's core and ebtree currently use
the same copy of the compiler.h file. That way we don't have any issue
anymore when one setting changes somewhere.
