abseil-cpp

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Author	SHA1	Message	Date
Abseil Team	a05366d851	Export of internal Abseil changes -- 04cb3b22497190170aa5b774e98080c5de2ba60b by Abseil Team <absl-team@google.com>: Alternative bit mixer for LowLevelHash on ARM LowLevelHash's bit-mixer is inefficient on ARM because it calculates a 128-bit product of two 64-bit numbers. On ARM, this requires a sequence of two instructions with a high combined latency and poor throughput. This change provides alternative bit-mixing code for ARM that uses only 64-bit arithmetic (multiplication, xor, and left-shifts) and speeds things up considerably. The bit-mixing code for ARM was inspired by by Woothash[1] and xxh3[1]. Once I landed on a sequence of operations that provided good mixing, I used a test harness to search for the combination of shift / rotate factors that provided the best mixing, as indicated by SMHasher hash quality tests. The new mixing code passes 13 out of 15 of the hash quality test suites in SMHasher, with the two failures being in the noise range: e.g. 1 collision vs. zero expected in a keyset of ~8m keys. [1]: https://github.com/tommyettinger/waterhash/blob/49f5cf0b63b9/woothash.h#L16-L20 [2]: https://github.com/Cyan4973/xxHash/blob/6853ddc36e46/xxhash.h#L3240-L3265 PiperOrigin-RevId: 391833008 -- 17a4de1f9d623155c75b19285d414cd55a487cd6 by Saleem Abdulrasool <abdulras@google.com>: debugging: add support for unwinding on RISCV Linux This adds partial support for unwinding the RISCV call stack. It is largely duplicated from the AArch64 support with alterations for the ELF RISCV psABI. This covers RISCV64 and RISCV32, though not the ILP32E calling convention. PiperOrigin-RevId: 391818522 -- 32c93e449327b2cea32b32f6365e84b420fe1ed3 by Gennadiy Rozental <rogeeff@google.com>: New storage for types smaller than 8 bytes. Also adding new read interface for types smaller than or rqual to 8 bytes to avoid passing the pointer. PiperOrigin-RevId: 391726822 -- e987ac08a7787801cbfc7d7c96649e97fa8cff1a by Abseil Team <absl-team@google.com>: Extern template `find_first_non_full` to reduce linkage size for TU with single not inlined function. PiperOrigin-RevId: 391718862 -- 73af9bfcb5bf045089133e18bbd20eb5bb699172 by Gennadiy Rozental <rogeeff@google.com>: Make most non-mutable most int128 methods and friend free functions constexpr. Some functions are implemented offline (at least in some configurations) and can't be made constexpr. Mutable methods can't be made constexpr until we drop c++11 support. Fixes #978 PiperOrigin-RevId: 391706535 GitOrigin-RevId: 04cb3b22497190170aa5b774e98080c5de2ba60b Change-Id: If051fad5ff004e2e82fa53618fc04a6fe3d2d4be	3 years ago
Abseil Team	8910297baf	Export of internal Abseil changes -- 3a9b4e8e5ecba532db5cc4ac12d12660307ce9fb by Derek Mauro <dmauro@google.com>: Use the Bazel @platforms repository for platform constraints Fixes #1000 PiperOrigin-RevId: 390644226 -- b34e4d2f8a86b54bd483ec4c9c3dd781ad2d8b68 by Abseil Team <absl-team@google.com>: debugging: add some handling for RISC-V The RISC-V architecture uses a downward growing stack and can host Linux using ELF files. Adjust a few sites accordingly to indicate how to handle the RISC-V architecture. PiperOrigin-RevId: 390631894 -- 5fa3a0961bf3dd0799c048956a0128f7b8113f1e by Samuel Benzaquen <sbenza@google.com>: Rename the buffer hash function to LowLevelHash. Although it started as wyhash, it will depart from it so it does not make sense to keep the name. PiperOrigin-RevId: 390483506 -- 2e7867a2301d58ad4cd5abcaa5fd6f0db973ae7b by Abseil Team <absl-team@google.com>: This is an internal change. PiperOrigin-RevId: 390349746 GitOrigin-RevId: 3a9b4e8e5ecba532db5cc4ac12d12660307ce9fb Change-Id: I322c3762552a2107e6c6b108c25c01e5efa8aecd	3 years ago
Abseil Team	5d8fc91922	Export of internal Abseil changes -- fcedaa5714efab8738446fa21620b827a40a3458 by Derek Mauro <dmauro@google.com>: Uses Wyhash in the implementation of absl::Hash for hashing sequences of more than 16 bytes on some platforms. Due to the per-process randomization of the seed used by absl::Hash, users should not notice this change, other than possibly getting better performance. This change only affects platforms where absl::uint128 is implemented with an intrinsic (and where sizeof(size_t)==8) since Wyhash relies on fast 128-bit multiplication for speed. PiperOrigin-RevId: 343956735 -- 085e108c760084f19caa21dbeb2118de2be3f8f0 by Abseil Team <absl-team@google.com>: Internal change for cord ring PiperOrigin-RevId: 343919274 -- 4c333278ad14d6692f203074b902506008ad624a by Jorg Brown <jorg@google.com>: Minimize strings_internal::StringConstant further, by removing the need for the compiler to instantiate a compile-time class function. PiperOrigin-RevId: 343878568 -- 71c3c8c7b7821b67997e3d5345aaec67f93f266f by Abseil Team <absl-team@google.com>: Internal change PiperOrigin-RevId: 343838259 GitOrigin-RevId: fcedaa5714efab8738446fa21620b827a40a3458 Change-Id: Ifb91895a82d11e743acd42fe97ab7fb70712b7df	4 years ago

Author

SHA1

Message

Date

Abseil Team

a05366d851

Export of internal Abseil changes

--
04cb3b22497190170aa5b774e98080c5de2ba60b by Abseil Team <absl-team@google.com>:

Alternative bit mixer for LowLevelHash on ARM

LowLevelHash's bit-mixer is inefficient on ARM because it calculates a 128-bit product of two 64-bit numbers. On ARM, this requires a sequence of two instructions with a high combined latency and poor throughput. This change provides alternative bit-mixing code for ARM that uses only 64-bit arithmetic (multiplication, xor, and left-shifts) and speeds things up considerably.

The bit-mixing code for ARM was inspired by by Woothash[1] and xxh3[1]. Once I landed on a sequence of operations that provided good mixing, I used a test harness to search for the combination of shift / rotate factors that provided the best mixing, as indicated by SMHasher hash quality tests. The new mixing code passes 13 out of 15 of the hash quality test suites in SMHasher, with the two failures being in the noise range: e.g. 1 collision vs. zero expected in a keyset of ~8m keys.

  [1]: https://github.com/tommyettinger/waterhash/blob/49f5cf0b63b9/woothash.h#L16-L20
  [2]: https://github.com/Cyan4973/xxHash/blob/6853ddc36e46/xxhash.h#L3240-L3265

PiperOrigin-RevId: 391833008

--
17a4de1f9d623155c75b19285d414cd55a487cd6 by Saleem Abdulrasool <abdulras@google.com>:

debugging: add support for unwinding on RISCV Linux

This adds partial support for unwinding the RISCV call stack.  It is largely
duplicated from the AArch64 support with alterations for the ELF RISCV psABI.
This covers RISCV64 and RISCV32, though not the ILP32E calling convention.

PiperOrigin-RevId: 391818522

--
32c93e449327b2cea32b32f6365e84b420fe1ed3 by Gennadiy Rozental <rogeeff@google.com>:

New storage for types smaller than 8 bytes.

Also adding new read interface for types smaller than or rqual to 8 bytes to avoid passing the pointer.

PiperOrigin-RevId: 391726822

--
e987ac08a7787801cbfc7d7c96649e97fa8cff1a by Abseil Team <absl-team@google.com>:

Extern template `find_first_non_full` to reduce linkage size for TU with single not inlined function.

PiperOrigin-RevId: 391718862

--
73af9bfcb5bf045089133e18bbd20eb5bb699172 by Gennadiy Rozental <rogeeff@google.com>:

Make most non-mutable most int128 methods and friend free functions constexpr.

Some functions are implemented offline (at least in some configurations) and can't be made constexpr. Mutable methods can't be made constexpr until we drop c++11 support.

Fixes #978

PiperOrigin-RevId: 391706535
GitOrigin-RevId: 04cb3b22497190170aa5b774e98080c5de2ba60b
Change-Id: If051fad5ff004e2e82fa53618fc04a6fe3d2d4be

3 years ago

Abseil Team

8910297baf

Export of internal Abseil changes

--
3a9b4e8e5ecba532db5cc4ac12d12660307ce9fb by Derek Mauro <dmauro@google.com>:

Use the Bazel @platforms repository for platform constraints
Fixes #1000

PiperOrigin-RevId: 390644226

--
b34e4d2f8a86b54bd483ec4c9c3dd781ad2d8b68 by Abseil Team <absl-team@google.com>:

debugging: add some handling for RISC-V

The RISC-V architecture uses a downward growing stack and can host Linux using
ELF files.  Adjust a few sites accordingly to indicate how to handle the RISC-V
architecture.

PiperOrigin-RevId: 390631894

--
5fa3a0961bf3dd0799c048956a0128f7b8113f1e by Samuel Benzaquen <sbenza@google.com>:

Rename the buffer hash function to LowLevelHash.
Although it started as wyhash, it will depart from it so it does not make sense
to keep the name.

PiperOrigin-RevId: 390483506

--
2e7867a2301d58ad4cd5abcaa5fd6f0db973ae7b by Abseil Team <absl-team@google.com>:

This is an internal change.

PiperOrigin-RevId: 390349746
GitOrigin-RevId: 3a9b4e8e5ecba532db5cc4ac12d12660307ce9fb
Change-Id: I322c3762552a2107e6c6b108c25c01e5efa8aecd

3 years ago

Abseil Team

5d8fc91922

Export of internal Abseil changes

--
fcedaa5714efab8738446fa21620b827a40a3458 by Derek Mauro <dmauro@google.com>:

Uses Wyhash in the implementation of absl::Hash for hashing sequences
of more than 16 bytes on some platforms.

Due to the per-process randomization of the seed used by absl::Hash, users
should not notice this change, other than possibly getting better performance.

This change only affects platforms where absl::uint128 is implemented
with an intrinsic (and where sizeof(size_t)==8) since Wyhash relies on
fast 128-bit multiplication for speed.

PiperOrigin-RevId: 343956735

--
085e108c760084f19caa21dbeb2118de2be3f8f0 by Abseil Team <absl-team@google.com>:

Internal change for cord ring

PiperOrigin-RevId: 343919274

--
4c333278ad14d6692f203074b902506008ad624a by Jorg Brown <jorg@google.com>:

Minimize strings_internal::StringConstant further, by removing the need for the compiler to instantiate a compile-time class function.

PiperOrigin-RevId: 343878568

--
71c3c8c7b7821b67997e3d5345aaec67f93f266f by Abseil Team <absl-team@google.com>:

Internal change

PiperOrigin-RevId: 343838259
GitOrigin-RevId: fcedaa5714efab8738446fa21620b827a40a3458
Change-Id: Ifb91895a82d11e743acd42fe97ab7fb70712b7df

4 years ago

2 Commits (5e4ea1ce097f3571e7d87af33b6b30d11b3a211e)