tree 35cb238cad5e7cd348ee8a6c73d0945ed478c175
parent d1673c2191034a65b38c5553a19572f26b122703
author Chris Kennelly <ckennelly@google.com> 1536594435 -0400
committer Adam Langley <agl@google.com> 1537218179 +0000

Use sdallocx, if available, when deallocating.

Providing a size hint to the allocator is substantially faster,
especially as we already know/need the size for OPENSSL_cleanse.

We provide a weak symbol that falls back to free when a malloc with
sdallocx is not statically linked with BoringSSL.

Alternatives considered:
* Use dlsym():  This is prone to fail on statically linked binaries
  without symbols.  Additionally, the extra indirection adds call
  overhead above and beyond the linker resolved technique we're using.
* Use CMake rules to identify whether sdallocx is available:  Once the
  library is built, we may link against a variety of malloc
  implementations (not all of which may have sdallocx), so we need to
  have a fallback when the symbol is unavailable.

Change-Id: I3a78e88fac5b6e5d4712aa0347d2ba6b43046e07
Reviewed-on: https://boringssl-review.googlesource.com/31784
Reviewed-by: Chris Kennelly <ckennelly@google.com>
Reviewed-by: Adam Langley <agl@google.com>