[all-commits] [llvm/llvm-project] a3b745: [libc] add unsafe mode to strlen

[michaelrj-google via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: a3b745818d2e13b2899260239c7cab4bf75070f7
      https://github.com/llvm/llvm-project/commit/a3b745818d2e13b2899260239c7cab4bf75070f7
  Author: Michael Jones <michaelrj at google.com>
  Date:   2022-11-30 (Wed, 30 Nov 2022)

  Changed paths:
    M libc/CMakeLists.txt
    A libc/common_libc_tuners.cmake
    M libc/src/string/CMakeLists.txt
    M libc/src/string/string_utils.h

  Log Message:
  -----------
  [libc] add unsafe mode to strlen

The only safe way to implement strlen involves reading the string one
char at a time. It is faster to read in larger blocks, but this leads to
reading beyond the string boundary, which is undefined behavior. This
patch adds an implementation and flag to use this fast but unsafe
version of strlen.

Reviewed By: sivachandra

Differential Revision: https://reviews.llvm.org/D129808