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Diffstat (limited to 'skills/chapter25-codex-notes.md')
| -rw-r--r-- | skills/chapter25-codex-notes.md | 39 |
1 files changed, 35 insertions, 4 deletions
diff --git a/skills/chapter25-codex-notes.md b/skills/chapter25-codex-notes.md index be9768f8..f585f654 100644 --- a/skills/chapter25-codex-notes.md +++ b/skills/chapter25-codex-notes.md @@ -36,10 +36,16 @@ For shared viewer work, read [the graph viewer notes](graph-viewer-codex-notes.m Static `_spillScaled` also counts each inlined loop copy separately, without credit for eliminated calls; inspect the optimized call graph before calling a higher cross-chapter score an allocator regression. -- Prefer concrete ArrayList to List, common base classes to unnecessary - interfaces, and short names (`pred`, `proj`, `def`, `use`). Avoid redundant +- Use concrete JDK collection types in fields, parameters, and return types: + ArrayList, HashMap, HashSet, etc., rather than List, Map, or Set interfaces. + Prefer common base classes to unnecessary interfaces, and short names + (`pred`, `proj`, `def`, `use`). Avoid redundant Objects.requireNonNull. Prefer int[]/AryInt to List<Integer>; avoid large boxed ID collections (use arrays/BitSet or NBHML as appropriate). Node ID 0 means null. +- When both branches assign the same field or variable, prefer one assignment + with a ternary expression over an if/else. +- Space declaration initializers as `Type name = expression;`. Preserve + deliberate column alignment when it makes related declarations easier to read. - Do not introduce Java streams. Use loops and explicit sorts; ask Cliff before making any exception. - Cliff often debugs the same failure in parallel. If asked to work in a side @@ -65,6 +71,31 @@ For shared viewer work, read [the graph viewer notes](graph-viewer-codex-notes.m ## Mutability and chapter boundaries +- Chapter 28b emits one object per source CompUnit. Imported functions have + Fun/Summary/Return graphs until an object is materialized. SummaryNodes are + never inlineable bodies. Only local calls request speculative IR; an unused + imported function must not recursively fetch its callees. Function identity + survives materialization through GlobalBits and rewired call/return edges. +- Initialization summaries retain direct call/touch edges and parent edges. + A potential cycle requires full IR refinement before diagnosis: a helper + outside the SCC can provide the constant that removes an internal edge. + Native linking uses the compiler's resolved CompUnit object paths when + available. Object-only tests without a CodeGen list all link inputs explicitly; + TestC does no dependency search. Eval2 trusts TypeCheck and a coherent set of + library objects; it does not revalidate cross-object compatibility. + SummaryNode.load uses CodeGen.getElf directly; + Eval2 needs no extra byte snapshot or protection from rewritten object files. + Tests must isolate output paths to avoid writer/reader races. + Eval2 materializes one object's checked IR on demand and schedules it + independently; never reoptimize graphs with active evaluation frames. Eval2 + executes CLInit directly using shared run-once flags. The child's clinit + body checks its parent before setting its own flag, so Eval2 and Lower need + only the requested class's flag-test/call at each active use. +- Summary escape information must include retention on nonreturning paths and + references passed by new callers. Result types alone do not capture this. + Import reanalysis releases prior SCCP memory keeps before starting another + solve; freshly deserialized nodes need parser-like construction semantics. + - Prefix updates must share ordinary name resolution: a method's bare field name denotes memory, while constructor fields may still be local SSA values. Do not update the declaration's scope slot before resolving that distinction. @@ -153,8 +184,8 @@ For shared viewer work, read [the graph viewer notes](graph-viewer-codex-notes.m - CLInit lowering (2026-10-17): TypeCheck queues surviving markers; optional Serialize saves opaque ideal IR, then Lower runs Iter before LoopTree. Serialization includes disconnected Returns and filters cross-object links - without mutating the live graph. Parent initialization precedes the child's - flag test/call; the true flag store remains inside the initializer. Runtime + without mutating the live graph. In Chapter 28b the child's initializer owns + both its parent-init check and its subsequent true flag store. Runtime flag reads follow ordinary Load idealization, including removing control. Handle x86 condition-flag lifetime constraints in the backend, not by pinning ideal Loads. Generated calls remain unlinked and |