On AArch64 it is sometimes convenient to have LSE atomics right from the start. Currently they are enabled after feature detection and RR reverse debugger works incorrectly.
New build configuration feature 'hardlse' is added. If it is enabled for aarch64 type of build, then statically compiled stubs replace the initial pessimistic implementation and dynamically generated replacements (when LSE support is detected). The feature works for builds of all debug levels. New file atomic_linux_aarch64_lse.S is derived from atomic_linux_aarch64.S and inherits its copyright. This alternative static implementation corresponds to the dynamically generated code. Note, this configuration part is necessary but not sufficient to fully avoid strex instructions for practical purposes. Other parts are: * Run on the OS built without strex family instructions. E.g. Amazon Linux 2022. * Compile with outline atomics enabled and the configuration flag enabled. E.g. configure with --with-extra-cflags='-march=armv8.3-a+crc+crypto -moutline-atomics' --with-extra-cxxflags='-march=armv8.3-a+crc+crypto -moutline-atomics' --with-extra-ldflags='-Wl,--allow-multiple-definition' --with-jvm-features=hardlse Testing: tier1, tier2 on linux-aarch64 release builds with feature off and feature on. ------------- Commit messages: - Merge branch 'openjdk:master' into JDK-8282322 - hardlse feature Changes: https://git.openjdk.java.net/jdk/pull/8779/files Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8779&range=00 Issue: https://bugs.openjdk.java.net/browse/JDK-8282322 Stats: 194 lines in 5 files changed: 193 ins; 0 del; 1 mod Patch: https://git.openjdk.java.net/jdk/pull/8779.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/8779/head:pull/8779 PR: https://git.openjdk.java.net/jdk/pull/8779
