diff options
Diffstat (limited to 'skills')
| -rw-r--r-- | skills/chapter25-codex-notes.md | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/skills/chapter25-codex-notes.md b/skills/chapter25-codex-notes.md index d0151805..24a57c02 100644 --- a/skills/chapter25-codex-notes.md +++ b/skills/chapter25-codex-notes.md @@ -155,9 +155,9 @@ lessons rather than duplicating that history. membership, seeds, or targets when comparing chapters. - Chapter 20's corrected baseline costs one extra weighted move (354->355 over 39 compilations); document this as a correctness cost. Advanced quality - heuristics remain staged. Chapters 20-22 are now implemented; common correctness + heuristics remain staged. Chapters 20-23 are now implemented; common correctness fixes and diagnostic hooks have also been forwarded through 25 at Cliff's request. - Resume the quality/cohort/README review at 23. Chapter 21's shortened README links the retained encoding reference. + Resume the quality/cohort/README review at 24. Chapter 21's shortened README links the retained encoding reference. - Chapter 21 changed several inherited inputs/ABIs. Its Chapter20Test now freezes all 13 original programs; Chapter21AllocTest retains the four revised cases, counted with the native variants as cohort 21. On Windows the cohorts are @@ -166,6 +166,16 @@ lessons rather than duplicating that history. popular-use grouping remains for 23. Preserve `person21` (64-bit age) separately from 22's narrower person example, and keep its revised infinite-loop input in cohort 22. The Windows cohort counts are 39, 52, and 24. +- Chapter 23 groups popular single-def uses by compatible register masks. One + intersection pass suffices: narrowing a class preserves its earlier users, + and newly added classes are disjoint. Snapshot distinct users before rewiring, + ignore null register masks, and count a call once despite repeated arguments. + The grouping correction/regression is already forwarded through 25. +- Chapter 23's frozen cohorts count 39, 52, 24, and 30 allocations. Preserve + `stringHash21` (with the old guard); its revised source and newly enabled Jig + tests belong to 23. Grouping on/off gives identical 933 raw / 1,745 weighted + moves here; report the zero gain rather than implying every heuristic helps + this suite. The earlier-cohort increase includes changed optimizer behavior. - Validate the instruction masks independently of the chosen register: a broad mask can hide behind favorable color bias. Byte/short x86 and RISC-V stores must exclude floating-point registers. Size fields such as `_sz` may hold a @@ -194,6 +204,14 @@ lessons rather than duplicating that history. Check real results and unchanged flags; successful allocation/encoding alone does not establish execution correctness. The 1,170-case Chapter 21 seed sweep now passes through encoding, and the original ARM/RISC-V hash results agree. +- For ARM execution probes, finish in-memory export so external relocations + (especially calloc) are patched, then select the intended function entry. + Encoding alone leaves placeholder branches. Check return PC, SP, callee-saved + registers, and the result; passing an instruction budget is not completion. +- ARM call/frame fixes are present in 21-25: ADD/SUB immediates are unsigned + magnitudes, frames use byte counts and 16-byte alignment, BL writes only X30, + and RET names X30 explicitly. Test instruction words independently of the + compiler so matching encoder/emulator mistakes cannot validate each other. - Copy cleanup/reuse must check kill masks even when an instruction has no LRG; before coloring, a fixed-register definition can clobber despite `_reg==-1`. Cloning is valid only if its output mask can satisfy the use. A fixed-register |