--- passes/auto_reg.lua — Per-phase automatic GPR allocator + gen/auto_reg.h emitter. --- --- Reads the per-source + corpus-level `atom_auto_regs` + `phase_auto_regs` registries populated by `passes/scan_source.lua`. --- Runs a deterministic first-fit allocator in the `R_T0..R_T7 + R_V0..R_V1` pool (10 physical GPRs). --- Emits one `#define R__Code R_Tn_Code` per marker into per-directory `gen/auto_reg.h`. --- --- User-pinned GPRs : The corpus's `register_alias_registry` is consulted to exclude GPRs the user has pinned via --- `atom_reg` + `_Code` defs (e.g. carriers like `R_ResolveScratch = R_T4 atom_reg`). --- These GPRs are unavailable to EVERY atom's source pool. --- Carriers are preserved across atoms by context discipline and must never be reallocated. --- Per-atom body parsing also catches alias references (R_) and hardcoded R_Tn references, --- so the user can write either `R_T4` or `R_ResolveScratch` in an atom body and the pass will --- exclude R_T4 from that atom's pool. --- --- Conflict detection: If the user hardcodes `R_Tn` in an atom body that shares a phase with an auto-reg that picked `R_Tn`, --- emit `phase_register_clash` as an info finding (no build stop). --- Should be unreachable after the user-pinning + body-parsing fix above; kept as a defensive safety net. --- --- Pool exhaustion: If a phase declares more `R_` mappings than the 10-register pool can hold, --- emit `phase_register_pool_exhausted` as a build-stopping error. --- @class AutoRegResult --- @field outputs table[] -- {kind=, path=} entries --- @field errors table[] -- {line=, msg=} entries (build-stops) --- @field warnings table[] -- {line=, msg=} entries (build-continues) local _bootstrap_dir = debug.getinfo(1, "S").source:match("^@?(.*[/\\])") or "./" local duffle = dofile(_bootstrap_dir .. "../duffle_paths.lua") --- ════════════════════════════════════════════════════════════════════════════ --- THE GPR ALLOCATION POOL — what is allocatable, and (more importantly) WHY --- ════════════════════════════════════════════════════════════════════════════ --- --- The auto-reg pass picks physical GPRs for `atom_auto_reg(...)` / `phase_auto_reg(...)` markers. --- It allocates from a FIXED 10-register pool. --- This comment block makes the inclusion AND exclusion criteria obvious so a reader doesn't have --- to grep lottes_tape.h + mips.h to understand the design. --- --- ── WHAT'S IN THE POOL (10 GPRs, all caller-trash per the O32 ABI) ──────── --- R_T0..R_T7 (GPR codes 8..15), R_V0..R_V1 (GPR codes 2..3) --- The workhorse of every atom body. The uesr should be aware of atom allocation across atoms they chain. --- If they have a collision it means either they didn't saturate the register file optimally for a phase, --- or the may have made the workload to large for the run. --- --- ── WHAT'S NOT IN THE POOL — and WHY (the "obvious exclusions") ──────────── --- R_T9 (GPR code 25) — R_TapePtr, the tape instruction stream pointer. --- Owned by the tape runtime (in tape_run / tape_run_a02_s07). --- `rgcc(R_TapePtr)` register-variable ties the C compiler's view to $t9 across the whole tape_run. --- The auto-reg pass MUST NOT clobber this; doing so would desync the C-side tape pointer from the --- hardware pointer and crash on the next tape_run. --- --- R_T8 (GPR code 24) — R_AtomJmp, the atom-jump register used by the 4-word yield handshake. --- Every `mac_yield()` / `mac_yield_tail` does `load_word R_AtomJmp, R_TapePtr, 0` then --- `jump_reg R_AtomJmp`. The auto-reg pass MUST NOT clobber this either, or the atom dispatcher breaks. --- Owned by the tape runtime, same family as R_TapePtr. --- --- R_AT (GPR code 1) — Assembler temporary. Reserved by the MIPS O32 ABI for pseudoinstruction expansion --- (lottes_tape.h:86, mips.h:93). The ISA's psuedo instructions use it as a scratch temporary. --- --- R_A0..A3 (codes 4..7) — Function arguments. Used in tape_run_a02_s07, see below. --- R_S0..S7 (codes 16..23) — Callee-saved. Preserved across C-ABI calls by convention. --- The `tape_run_a02_s07` variant clobbers them deliberately, but the default `tape_run` does NOT. --- Kept out of POOL to preserve the conservative default. --- Add them in a separate "big clobber" pool if/when needed. --- --- R_K0/K1 (codes 26..27) — Kernel / interrupt handler reserves. Never touched by user code; OS-internal. --- R_GP/SP/FP/RA (codes 28..31) — Stack frame + return-address. Owned by the C compiler; never allocatable. --- R_0 (code 0) — Hardwired zero. Cannot be written. --- local POOL = { "R_T0", "R_T1", "R_T2", "R_T3", "R_T4", "R_T5", "R_T6", "R_T7", "R_V0", "R_V1", } -- Map from integer MIPS GPR code (the `code` field on AliasEntry) to the physical GPR ident in POOL. -- The standard MIPS O32 ABI register numbering matches mips.h's R_*_Code #defines (mips.h). -- Only the POOL entries matter for auto_reg — non-pool aliases -- (R_AT=1, R_A0..A3=4..7, R_T8=24, R_T9=25, R_K0/K1=26..27, R_GP/SP/FP/RA=28..31) -- are deliberately omitted — see the comment block above for the WHY of each exclusion. local INT_CODE_TO_POOL_GPR = { [2] = "R_V0", [3] = "R_V1", [8] = "R_T0", [9] = "R_T1", [10] = "R_T2", [11] = "R_T3", [12] = "R_T4", [13] = "R_T5", [14] = "R_T6", [15] = "R_T7", } -- Stable sort for deterministic allocation order. local function stable_sort_keys(tbl) local keys = {} for k in pairs(tbl) do keys[#keys + 1] = k end table.sort(keys) return keys end -- Allocate one phase's auto-reg mappings. -- Returns (allocated_map, errors). On pool exhaustion, errors is populated and the function halts. local function allocate_phase(phase_label, decls) -- Deep-copy POOL into a fresh sequence table. The original `table.unpack and table.unpack(POOL) or { unpack(POOL) }` -- idiom wraps the unpacked values in a single inner table under LuaJIT 5.1 (`table.unpack` is nil; the `or` returns one value), -- which corrupts the pool into `{ {R_T0, R_T1, ...} }` — making `table.remove(pool, 1)` return the inner table on iteration. local pool = {} for i = 1, #POOL do pool[i] = POOL[i] end local result = {} local errors = {} for _, sym in ipairs(stable_sort_keys(decls)) do local next_gpr = table.remove(pool, 1) if not next_gpr then errors[#errors + 1] = { line = 0, msg = string.format("phase_register_pool_exhausted: " .. "phase '%s' requested symbol '%s' but the pool has no remaining registers " .. "(max 10 per phase: R_T0..R_T7 + R_V0..R_V1). Split the phase or use hardcoded GPRs." , phase_label, sym), } return result, errors end result[sym] = next_gpr end return result, errors end -- Build two projections from corpus.register_alias_registry: -- user_pinned -- { [physical_gpr_ident] = true } -- GPRs unavailable to auto_reg globally (wave-context carriers, file-scope pinned aliases) -- alias_to_gpr -- { [alias_ident] = physical_gpr_ident } -- for body parsing -- Both projections are derived from the same set of entries: every AliasEntry in register_alias_registry has `has_atom_reg = true` -- (only those entries are added to the registry; see passes/scan_source.lua parse_enum_entry). -- Each entry's `code` is the integer MIPS GPR number (0..31); INT_CODE_TO_POOL_GPR translates it back to the physical GPR ident. -- Aliases whose `code` points to a non-POOL GPR (e.g. R_S0, R_T8, R_K1) are ignored — -- they don't affect the auto_reg pool, and they're already excluded from POOL above. local function build_user_pins(corpus) local user_pinned = {} local alias_to_gpr = {} if not corpus.register_alias_registry then return user_pinned, alias_to_gpr end for alias_name, alias_entry in pairs(corpus.register_alias_registry) do if alias_entry.has_atom_reg and alias_entry.code then local gpr = INT_CODE_TO_POOL_GPR[alias_entry.code] if gpr then user_pinned[gpr] = true alias_to_gpr[alias_name] = gpr end end end return user_pinned, alias_to_gpr end -- Find every physical GPR referenced in the atom body, via EITHER: -- (a) A hardcoded physical GPR ident (R_T\d+|R_V\d+|R_A\d+|R_S\d+) — the existing regex; -- (b) An alias ident (R_) resolved via alias_to_gpr back to its physical GPR ident. -- Returns { [physical_gpr_ident] = count }. Clash-detection and source-pool-exclusion logic -- only needs the presence of each GPR (boolean test), but keeping count preserves the -- original find_hardcoded_rn shape so callers can switch without churn. -- The alias pattern is sorted lexicographically to keep the regex deterministic. local function find_used_gprs(body_text, alias_to_gpr) local found = {} -- (a) Hardcoded physical GPRs (R_T0..R_T7, R_V0..R_V1, R_A0..R_A3, R_S0..R_S7). for gpr in body_text:gmatch("(R_T%d+|R_V%d+|R_A%d+|R_S%d+)") do found[gpr] = (found[gpr] or 0) + 1 end -- (b) Alias references (R_) resolved to physical GPRs via the registry. -- Sorted by name so the regex is byte-stable across runs. if alias_to_gpr and next(alias_to_gpr) then local aliases = {} for alias_name in pairs(alias_to_gpr) do aliases[#aliases + 1] = alias_name end table.sort(aliases) local pattern = "(" .. table.concat(aliases, "|") .. ")" for alias_name in body_text:gmatch(pattern) do local gpr = alias_to_gpr[alias_name] if gpr and not found[gpr] then found[gpr] = 1 end end end return found end -- Emit one gen/auto_reg.h header per directory. local function emit_auto_reg_h(out_dir, dir, sources, mappings) if not mappings or next(mappings) == nil then return end local out_path = out_dir .. "/" .. "auto_reg.h" duffle.ensure_dir(out_dir) local lines = { "#ifdef INTELLISENSE_DIRECTIVES", "#pragma once", "#endif", "// Auto-generated by ps1_meta.lua (passes/auto_reg.lua) — DO NOT EDIT", "// Directory: " .. dir:gsub("/", "\\"), } for _, src in ipairs(sources) do lines[#lines + 1] = "// source: " .. src.path end lines[#lines + 1] = "// Per-phase register allocations resolved by the lua pass." lines[#lines + 1] = "// R__Code = for every marker in this directory." lines[#lines + 1] = "" for _, sym in ipairs(stable_sort_keys(mappings)) do local gpr = mappings[sym] local gpr_code = gpr .. "_Code" lines[#lines + 1] = "#define " .. sym .. "_Code " .. gpr_code end lines[#lines + 1] = "" duffle.write_file_lf(out_path, table.concat(lines, "\n") .. "\n") print(" -> " .. out_path) return out_path end -- ════════════════════════════════════════════════════════════════════════════ -- Pass entry -- ════════════════════════════════════════════════════════════════════════════ local M = {} --- @param ctx PassCtx --- @return AutoRegResult function M.run(ctx) local outputs = {} local errors = {} local warnings = {} local corpus = ctx.shared and ctx.shared.corpus if type(corpus) ~= "table" then error("auto_reg.run requires ctx.shared.corpus", 0) end -- 0. Build the user-pinned GPR exclusion set + alias-to-GPR resolution map. -- Wave-context carriers (e.g. `R_ResolveScratch = R_T4 atom_reg` in hello_camera.atom.c) -- MUST NOT be allocated to any auto-reg marker — they're preserved across atoms by the wave-context discipline. -- The corpus's register_alias_registry is the source of truth for these opt-in pins. -- Body references to those aliases (via alias_to_gpr) are also excluded on a per-atom basis in step 2 below. local user_pinned, alias_to_gpr = build_user_pins(corpus) -- 1. Allocate phase pools first (phase declarations take precedence over per-atom declarations). local phase_allocations = {} for phase_label, decls in pairs(corpus.phase_auto_regs or {}) do local mapping, errs = allocate_phase(phase_label, decls) for sym, gpr in pairs(mapping) do phase_allocations[phase_label] = phase_allocations[phase_label] or {} phase_allocations[phase_label][sym] = gpr end for _, e in ipairs(errs) do errors[#errors + 1] = e end end -- 2. Allocate per-atom auto-regs. If the atom scope matches a phase, reuse the phase pool. -- Otherwise, allocate a private pool for the atom. -- The phase membership is in `corpus.atom_phases[phase_label].atoms` (an array of atom names declared via `atom_phase()` -- in the atom's `atom_info` line). Build a reverse map `atom_name -> phase_label` so the lookup is O(1) per atom scope. local atom_name_to_phase = {} for phase_label, entry in pairs(corpus.atom_phases or {}) do for _, atom_name in ipairs(entry.atoms or {}) do atom_name_to_phase[atom_name] = phase_label end end local atom_allocations = {} for atom_scope, decls in pairs(corpus.atom_auto_regs or {}) do local phase_label = atom_name_to_phase[atom_scope] -- Build the atom's source pool: start with the full POOL, subtract: -- (a) every GPR already committed (phase allocations + prior atom allocations) -- (b) every USER-PINNED GPR (wave-context carriers + file-scope pinned aliases) -- (c) every GPR referenced in the atom's body — either hardcoded R_X or alias R_Xxx -- (the latter resolved via alias_to_gpr; this catches cases where the user wrote R_ResolveScratch instead of R_T4 directly) -- Atoms whose scope matches a phase share the global pool with the phase allocations; -- the original `source_pool = phase_allocations[phase_label]` form used the phase -- allocation MAP as a pool, but that map has no array part, so `table.remove(source_pool, 1)` -- returned nil and every atom-with-phase marker errored with `phase_register_pool_exhausted`. local used = {} for _, m in pairs(phase_allocations) do for _, gpr in pairs(m) do used[gpr] = true end end for _, m in pairs(atom_allocations) do for _, gpr in pairs(m) do used[gpr] = true end end -- (c) Body references — scan the atom body for hardcoded + alias-resolved GPRs. -- Folded into `used` so the source_pool exclusion is a single check. local atom = corpus.atoms_by_name and corpus.atoms_by_name[atom_scope] if atom and atom.body then local body_used = find_used_gprs(atom.body, alias_to_gpr) for gpr in pairs(body_used) do used[gpr] = true end end local source_pool = {} for _, gpr in ipairs(POOL) do -- Exclude (a) prior commitments, (b) USER-PINNED GPRs (wave-context carriers -- declared via atom_reg + _Code defs, preserved across atoms globally). if not used[gpr] and not user_pinned[gpr] then source_pool[#source_pool + 1] = gpr end end local result = {} for _, sym in ipairs(stable_sort_keys(decls)) do local next_gpr = table.remove(source_pool, 1) if not next_gpr then errors[#errors + 1] = { line = 0, msg = string.format("phase_register_pool_exhausted: atom '%s' requested symbol '%s' " .. "but no free registers remain in its scope pool." , atom_scope, sym), } else result[sym] = next_gpr end end atom_allocations[atom_scope] = result end -- 3. Conflict-with-hardcoded detection (defensive — should be unreachable now). -- The source_pool exclusion in step 2 (b) + (c) already accounts for both user-pinned GPRs -- and body-referenced GPRs (hardcoded R_Tn OR alias R_). -- An auto-reg allocation that matched an existing body reference would be impossible by construction. -- This warning is kept as a defensive safety net for cases the body scanner might miss -- (e.g. macros that expand to register references the scanner cannot resolve). -- For each resolved (scope, sym) -> R_Tn mapping, scan the atom body source for used GPRs. for atom_scope, decls in pairs(atom_allocations) do local atom = corpus.atoms_by_name and corpus.atoms_by_name[atom_scope] if atom and atom.body then local used_in_body = find_used_gprs(atom.body, alias_to_gpr) for sym, allocated_gpr in pairs(decls) do if used_in_body[allocated_gpr] and used_in_body[allocated_gpr] > 0 then warnings[#warnings + 1] = { line = atom.line or 0, msg = string.format("phase_register_clash: atom '%s' has hardcoded '%s' in its body AND an auto-reg marker '%s' " .. "that was allocated to '%s' (same phase). Resolve by removing the hardcoded reference or renaming the auto-reg." , atom_scope, allocated_gpr, sym, allocated_gpr), } end end end end -- 4. Emit per-directory gen/auto_reg.h. -- For each source directory that has atom_auto_regs or phase_auto_regs entries, emit one header. local sources_by_dir = corpus.sources_by_dir or {} for dir, sources in pairs(sources_by_dir) do local per_dir_mappings = {} for _, src in ipairs(sources) do -- Collect every (sym -> gpr) entry that originated from a source in this directory. -- `src.scan.atom_auto_regs` is keyed by ATOM SCOPE NAME; `pairs(t)` iterates KEYS so `scope_name` here is the scope ident (e.g. "cube_g4_face"). -- The previous `for _, scan_atom_auto` form silently assigned the VALUE (a `{sym = sym}` table) to the variable, -- which made `atom_allocations[scan_atom_auto]` a table-indexed lookup that never resolved. for scope_name in pairs(src.scan and src.scan.atom_auto_regs or {}) do for sym, gpr in pairs(atom_allocations[scope_name] or {}) do per_dir_mappings[sym] = gpr end end for scope_name in pairs(src.scan and src.scan.phase_auto_regs or {}) do for sym, gpr in pairs(phase_allocations[scope_name] or {}) do per_dir_mappings[sym] = gpr end end end local out_dir = dir .. "/gen" local out_path = emit_auto_reg_h(out_dir, dir, sources, per_dir_mappings) if out_path then outputs[#outputs + 1] = { auto_reg_h = out_path } end end return { outputs = outputs, errors = errors, warnings = warnings } end return M