MMTk 0.20.0

What's Changed

Plan

• Refactor derive macros and add HasSpaces trait by @wks in #934
• Make MarkCompact LOS support 2nd transitive closure by @wenyuzhao in #944
• Disabling PrepareMutator from PlanConstraints by @wks in #964

Policy

• Add ExternalPageResource and allow discontiguous VM space by @qinsoon in #864
• Discontiguous mark compact space support by @wenyuzhao in #939
• Discontiguous PageProtect GC support by @wenyuzhao in #946
• Fix vo-bit reset for discontiguous space by @wenyuzhao in #948

API

• Boot-time configurable heap constants by @wenyuzhao in #899
• This PR enables transitively pinning (TP) objects from particular roots for Immix/StickyImmix by @udesou in #897
• Let VM control when or if to read env var options by @wks in #955

Misc

• Update doc comment of Scanning::process_weak_refs by @wks in #919
• Binding test for Ruby by @wks in #916
• Fix api-check CI by @wks in #923
• Fix default value for RUBY_BINDING_REPO by @qinsoon in #926
• Add a ready-to-merge check by @qinsoon in #910
• Run ready to merge check for PRs by @qinsoon in #928
• Remove cast ref to mut everywhere by @playXE in #893
• Benchmark Rust code by @qinsoon in #933
• Fix broken links in the tutorial by @caizixian in #936
• Update doc to add a section for LTO by @qinsoon in #937
• Add CARGO_INCREMENTAL=0 to work around clippy 1.72 bug by @qinsoon in #938
• Fix issues for cargo fmt in 1.72 by @qinsoon in #940
• Use atomic operations for SFT map and remove unsafe code by @qinsoon in #931
• Fix outdated Rust version in README by @qinsoon in #942
• Fix length of Map64::descriptor_map by @wks in #956

Full Changelog: v0.19.0...v0.20.0