tvl-depot/absl
Abseil Team 33841c5c96 Export of internal Abseil changes.
--
bb92c768e2271ddbebc1b1eb7e16a7b7c86a6e1c by Abseil Team <absl-team@google.com>:

Automated g4 rollback of changelist 244998488.

*** Reason for rollback ***

I'm seeing test failures, rolling this back.

*** Original change description ***

BEGIN_PUBLIC

The default constructor for optional<T> is filling dummy_ with zeros (see https://godbolt.org/z/IVea7X for a reduced example), which has a performance impact for large Ts. This comes from the gcc6 bugfix that made dummy as big as T. Because constexpr constructors are required to initialize all members of a struct, we cannot prevent this in a standard-compliant way as soon as dummy has any members (note that clang will happily accept adding a `constexpr dummy_type() {}` constructor...

***

PiperOrigin-RevId: 245004716

--
6e3ee35af50ffbee604c22300f3260ebc5f6cf52 by Abseil Team <absl-team@google.com>:

The default constructor for optional<T> is filling dummy_ with zeros (see https://godbolt.org/z/IVea7X for a reduced example), which has a performance impact for large Ts. This comes from the gcc6 bugfix that made dummy as big as T. Because constexpr constructors are required to initialize all members of a struct, we cannot prevent this in a standard-compliant way as soon as dummy has any members (note that clang will happily accept adding a `constexpr dummy_type() {}` constructor to dummy_type to prevent zero-initialization, but this is UB AFAICT).

This all stems from the fact that we're constructing an object by using placement new on dummy_. The solution I'm using here is to do the placement new on the actual data_. This creates a new issue in when T is volatile, because we can no longer use `&data_` to do the placement new. The solution I'm using here is to make data_ a non-const and non-volatile T, and only provide fully possibly qualified access through `reference()` accessors. I think this correctly prevents UB.

PiperOrigin-RevId: 244998488

--
4f52e64c4cf6aef8df6360007bcc53d8b00db2b4 by Abseil Team <absl-team@google.com>:

Increase SYMBOL_BUF_SIZE from 2KB to 3KB.

PiperOrigin-RevId: 244954529
GitOrigin-RevId: bb92c768e2271ddbebc1b1eb7e16a7b7c86a6e1c
Change-Id: Iaed9a027064a9ecd194c5c146169c683b77f12ef
2019-04-24 14:35:20 -04:00
..
algorithm Export of internal Abseil changes. 2019-04-23 15:57:17 -04:00
base Export of internal Abseil changes. 2019-04-23 15:57:17 -04:00
container Export of internal Abseil changes. 2019-04-23 15:57:17 -04:00
copts Export of internal Abseil changes. 2019-04-23 15:57:17 -04:00
debugging Export of internal Abseil changes. 2019-04-24 14:35:20 -04:00
hash Export of internal Abseil changes. 2019-04-24 14:35:20 -04:00
memory Export of internal Abseil changes. 2019-04-23 15:57:17 -04:00
meta Export of internal Abseil changes. 2019-04-23 15:57:17 -04:00
numeric Export of internal Abseil changes. 2019-04-23 15:57:17 -04:00
strings Export of internal Abseil changes. 2019-04-23 15:57:17 -04:00
synchronization Export of internal Abseil changes. 2019-04-23 15:57:17 -04:00
time Export of internal Abseil changes. 2019-04-23 15:57:17 -04:00
types Export of internal Abseil changes. 2019-04-23 15:57:17 -04:00
utility Export of internal Abseil changes. 2019-04-23 15:57:17 -04:00
BUILD.bazel Export of internal Abseil changes. 2019-04-23 15:57:17 -04:00
CMakeLists.txt Changed HTTP URLs to HTTPS where possible (#270) 2019-03-08 10:27:53 -05:00
compiler_config_setting.bzl Export of internal Abseil changes. 2019-03-19 14:19:10 -04:00