tree daa49fd6f6749056467b1356ab5217cf5e72aeac
parent 42329a828b25259fc47691f5b4a39caf2b29f058
author Adam Langley <agl@google.com> 1491329308 -0700
committer CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org> 1491329959 +0000

Make the POWER hardware capability value a global in crypto.c.

(Thanks to Sam Panzer for the patch.)

At least some linkers will drop constructor functions if no symbols from
that translation unit are used elsewhere in the program. On POWER, since
the cached capability value isn't a global in crypto.o (like other
platforms), the constructor function is getting discarded.

The C++11 spec says (3.6.2, paragraph 4):

    It is implementation-defined whether the dynamic initialization of a
    non-local variable with static storage duration is done before the
    first statement of main. If the initialization is deferred to some
    point in time after the first statement of main, it shall occur
    before the first odr-use (3.2) of any function or variable defined
    in the same translation unit as the variable to be initialized.

Compilers appear to interpret that to mean they are allowed to drop
(i.e. indefinitely defer) constructors that occur in translation units
that are never used, so they can avoid initializing some part of a
library if it's dropped on the floor.

This change makes the hardware capability value for POWER a global in
crypto.c, which should prevent the constructor function from being
ignored.

Change-Id: I43ebe492d0ac1491f6f6c2097971a277f923dd3e
Reviewed-on: https://boringssl-review.googlesource.com/14664
Commit-Queue: Adam Langley <agl@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>