From 253ac862c696d73fb17c14a847270b6e08aa8769 Mon Sep 17 00:00:00 2001 From: zinc Date: Thu, 15 Oct 2026 14:32:10 +0330 Subject: hold blocks: top-level hold { shared let ...; fn ... } monitors; shared values kept by the host and copied in/out at the outermost call, reentrant per-block locks in declaration order (core, micro) --- src/compiler/base.zc | 6 +++ src/compiler/decl.zc | 56 ++++++++++++++++++++++++- src/compiler/expr.zc | 10 +++++ src/core/core.c | 12 +++++- src/core/hold.h | 116 +++++++++++++++++++++++++++++++++++++++++++++++++++ src/micro/micro.c | 11 ++++- 6 files changed, 208 insertions(+), 3 deletions(-) create mode 100644 src/core/hold.h (limited to 'src') diff --git a/src/compiler/base.zc b/src/compiler/base.zc index 7e4b5bc..bd27e28 100644 --- a/src/compiler/base.zc +++ b/src/compiler/base.zc @@ -323,6 +323,12 @@ int s_ld8, s_st8, s_ld16, s_st16, s_ld32, s_st32; // ---- o3 region state ---- // each promoted slot maps to a register; pending regions use 67-word records and a descriptor buffer. +// hold blocks: hold_cur is the rank of the block being compiled (0 outside one), fhold the +// rank of the function being compiled, hold_desc the word that will point at the block's +// table of shared variables, hold_count the blocks so far. a shared variable's symbol has +// F_SHARED and its block's rank above it in sflag. +const int F_SHARED = 131072, F_SHARED_RANK = 262144; +int hold_cur, fhold, hold_count, hold_desc, hold_nshared; word[128] hold_tab; int o3on, o3nxt, o3one; word[32] o3sl; word[32] o3rg; int no3sl; word[O3_REGIONS * 67] o3pend_initial; word o3pend = o3pend_initial; int o3pendcap = O3_REGIONS, no3pend; word[80] o3dsc; int o3fs, o3na, o3fn0; // o3free holds registers released by closed scopes; o3cache holds the items pointer and length slots for fixed arrays. word[8] o3free; int no3free, o3nreg; word[NL] o3cache_initial; word o3cache = o3cache_initial; int argloc, s_hitems, s_hlen, s_fatten; diff --git a/src/compiler/decl.zc b/src/compiler/decl.zc index 52d08c7..fed7b8d 100644 --- a/src/compiler/decl.zc +++ b/src/compiler/decl.zc @@ -230,11 +230,61 @@ int prologue() { setlit(k, here); setlit(done, here); op(O_DROP); setlit(busy, here); return 0; } +// a function of a hold block takes the block's lock on entry (op 57 of the syscall gate) +// and gives it back at its one exit (op 58), with the return value left on the stack. the +// host keeps the shared values: entering the block from outside copies them into the +// block's variables, leaving copies them back, so inside, every read and write is a plain +// global access on every backend. the lock is reentrant and held for the whole call. +int hold_gate(int code) { + if (!fhold || nclo) return 0; + lit(fhold); lit(rt.SYSGATE + 1); op(O_ST); + lit(hold_desc); lit(rt.SYSGATE + 2); op(O_ST); + lit(code); lit(rt.SYSGATE); op(O_ST); + return 0; +} +// hold { shared let c; fn a() { ... } ... }: a monitor. the shared variables can be used +// only by the functions written in the block; each call holds the block's lock. +int kw_hold() { + int rank, d, before, s, i, w; word t; + if (hold_cur) serr("hold blocks don't nest"); + next(); expect(s_lb); + rank = hold_count + 1; hold_count = rank; + reserve_code(1); d = here; emit(0); + hold_cur = rank; hold_desc = d; hold_nshared = 0; + while (!is_op(s_rb)) { + if (tk == T_EOF) { die("missing } at the end of a hold block"); break; } + if (panic) { topsync(); continue; } + if (tk == T_ID && rt.eq_w(tv, "shared")) { + next(); before = nsym; + if (is_id(s_var)) gdecl(0); + else if (tstart()) { rettype(); gdecl2(dty, dtag, name()); } + else { die("expected let or a type after shared"); continue; } + s = before; + while (s < nsym) { + if (skind[s] == K_GVAR || skind[s] == K_GARR) { + t = stype[s]; w = 1; + if (skind[s] == K_GARR) { w = tsz(t); if (t[0] == TY_ARR) t = t[1]; } + if (t && (isptr(t) || isagg(t) || t == tbstr || t[0] == TY_DYN || t[0] == TY_FN)) serrn(sname[s], "is shared, so it holds numbers: no pointers, strings or structs (each actor has its own heap)"); + sflag[s] = sflag[s] | F_SHARED | rank * F_SHARED_RANK; + if (hold_nshared >= 64) serr("too many shared variables in one hold block (64)"); + else { hold_tab[hold_nshared * 2] = sval[s]; hold_tab[hold_nshared * 2 + 1] = w; hold_nshared++; } + } + s++; + } + } else topitem0(); + } + next(); + reserve_code(1 + hold_nshared * 2); *(d + hdelta) = here; emit(hold_nshared); + i = 0; while (i < hold_nshared * 2) { emit(hold_tab[i]); i++; } + hold_cur = 0; hold_desc = 0; + return 0; +} // emit the function epilogue, patching every return to it. int epilogue() { int k, node, done, helper = !nclo && (sname[finsym] == s_frame_grow || sname[finsym] == s_frame_leave); lit(0); fixall(epichain, here); + hold_gate(58); lit(rt.ZFP); op(O_LD); lit(fslots); op(O_ADD); lit(rt.ZFP); op(O_ST); if (!helper) { lit(sval[lookup(s_frame_node)]); op(O_LD); node = hole(); op(O_JZ); @@ -404,7 +454,9 @@ int fndef(int chk, int rty, int ret, int n) { if (typed && explicit_rty) fty = rty; no3pend = 0; if (o3f) { o3on = 1; o3reset(); sflag[s] = sflag[s] | F_O3; } - prologue(); borrow_prologue(); + fhold = hold_cur; + if (fhold && o3f) serrn(n, "is in a hold block and can't be o3"); + prologue(); borrow_prologue(); hold_gate(57); i = 0; while (i < np) { t = newloc(pn[i]); lrskind[t] = RS_PARAM; lrsoff[t] = pnoffs[i]; lpos[t] = pnplaces[i]; fslots++; lsmark(1, pn[i]); @@ -431,6 +483,7 @@ int fndef(int chk, int rty, int ret, int n) { } hi = here; epilogue(); + fhold = 0; lend = here; if (o3f) { o3on = 0; @@ -720,6 +773,7 @@ int topitem1() { if (!is_op(s_lp)) { die("expected a function"); return 0; } return fndone(fndef(chk, dty, dtag == S_U, n), imm); } + if (tk == T_ID && rt.eq_w(tv, "hold")) { peek(); if (pk_tk == T_OP && pk_tv == s_lb) return kw_hold(); } if (is_id(s_var)) return gdecl(0); if (is_id(s_struct)) { kw_struct(); return 0; } if (is_id(s_type)) return kw_type(); diff --git a/src/compiler/expr.zc b/src/compiler/expr.zc index a6cc55c..141ca16 100644 --- a/src/compiler/expr.zc +++ b/src/compiler/expr.zc @@ -657,6 +657,15 @@ word closure_layout(int closure_index, int count) { // the code that creates the closure runs, it allocates the block (code, then // captured values), writes the three code words and copies each captured // variable in. ctx_push / ctx_pop save and restore the enclosing function's +// a shared variable is reachable only from a function of its own hold block, which holds +// the block's lock for the whole call. a closure might run after the call returns. +int shared_use(int s) { + int rank = sflag[s] / F_SHARED_RANK; + if (fhold == rank && !nclo && infn) return 0; + if (fhold == rank && nclo) { serrn(sname[s], "is shared; a closure can't use it, because it may run after the hold block's lock is released"); return 0; } + serrn(sname[s], "is shared in a hold block; only the functions written inside that block can use it (they hold its lock)"); + return 0; +} // compiler state around the body. int closure() { char* xcf; @@ -1095,6 +1104,7 @@ int primary() { xcval = sval[s]; return C_PLAIN; } + if (s >= 0 && (skind[s] == K_GVAR || skind[s] == K_GARR) && (sflag[s] & F_SHARED)) shared_use(s); if (s >= 0 && skind[s] == K_GVAR) { if (cmode) { vf_symbols(); xvk = svkind[s]; xvv = svvalue[s]; vf_at(rsn - 1, xvk, xvv); } lit(sval[s]); diff --git a/src/core/core.c b/src/core/core.c index 648f54a..7d1b91e 100644 --- a/src/core/core.c +++ b/src/core/core.c @@ -74,6 +74,10 @@ #include "memmap.h" #include "fops.h" #include "bops.h" +#if !defined(_WIN32) && !defined(__wasm__) +#define HOLD_THREADS +#endif +#include "hold.h" #ifndef JTYPE #define JTYPE char @@ -295,6 +299,12 @@ static Cell hostcall(Cell op, Cell a, Cell b, Cell c) #else return -1; #endif + case 57: { + Cell r = hold_enter(m, (uint64_t)MW, a, b); + if (r == -2) { fflush(stdout); fprintf(stderr, "zy: hold block %d was entered while block %d was held; hold blocks are entered in the order they are declared\n", (int)a, hold_top); exit(2); } + return r; + } + case 58: return hold_leave(m, (uint64_t)MW, a, b); case 56: return cb_r; /* the return stack pointer as of the gate store: the word after the top return address */ case 1: if (zcstr(a, path, 1024) < 0) return -1; @@ -7646,7 +7656,7 @@ static void *context_worker(void *opaque) { if (!context->requested_exit) context->exit_code = context_cancelled() ? 0 : stopped(back) ? -1 : inmem(sp) ? (int)m[sp] : 0; context_channel_close(context->worker_channel.handle); while (context_children) context_join(context_children->token, 1); - context_engine_free(); context_current = 0; return 0; + hold_release_all(); context_engine_free(); context_current = 0; return 0; } static Cell context_start(Cell entry, Cell channel) { VmContext *context; int fd[2], i; pthread_attr_t attributes; Cell saved; diff --git a/src/core/hold.h b/src/core/hold.h new file mode 100644 index 0000000..d4ab1f0 --- /dev/null +++ b/src/core/hold.h @@ -0,0 +1,116 @@ +/* hold blocks (spec 4.16): the host side of a monitor. a function of a hold block + stores op 57 (enter) at its start and op 58 (leave) at its exit, with the block's + rank and the address of its descriptor word. the descriptor points at a table in vm + memory: n, then n pairs (address, words) of the block's shared variables. + + the shared values live here, outside every vm, so all actors (each with its own + memory) see one copy. entering a block from outside takes its lock and copies the + values into the vm's variables; leaving copies them back and unlocks. inside, they + are plain globals. the lock is per block and reentrant per thread (a nested call + only counts), and blocks are taken in rank (declaration) order: entering a block + while holding a later one is an error, which rules out lock-order deadlocks between + blocks. a worker that ends while holding blocks releases them without writing back. + + included by src/core/core.c and src/micro/micro.c; HOLD_THREADS selects pthreads, + otherwise a single machine needs no locks (wasm, bare metal). no malloc. */ +#ifndef HOLD_H +#define HOLD_H +#define HOLD_BLOCKS 256 +#define HOLD_CELLS 65536 +#ifdef HOLD_THREADS +#include +static pthread_mutex_t hold_lock[HOLD_BLOCKS], hold_meta = PTHREAD_MUTEX_INITIALIZER; +static pthread_once_t hold_once = PTHREAD_ONCE_INIT; +static void hold_init(void) { int i; for (i = 0; i < HOLD_BLOCKS; i++) pthread_mutex_init(&hold_lock[i], 0); } +#define HOLD_TLS _Thread_local +#else +#define HOLD_TLS +#endif +static int64_t hold_cells[HOLD_CELLS]; +static int hold_base[HOLD_BLOCKS], hold_size[HOLD_BLOCKS], hold_ready[HOLD_BLOCKS], hold_next; +static HOLD_TLS int hold_depth[HOLD_BLOCKS], hold_top; /* this thread: nesting per block, highest rank held */ +static HOLD_TLS unsigned char hold_order[HOLD_BLOCKS]; /* ranks held, in the order taken */ +static HOLD_TLS int hold_n; + +/* the table's entries, checked against the machine. -1 when it is malformed */ +static int64_t hold_table(int64_t *mem, uint64_t words, int64_t desc, int64_t *n) +{ + int64_t t, i; + if (desc <= 0 || (uint64_t)desc >= words) return -1; + t = mem[desc]; + if (t <= 0 || (uint64_t)t >= words) return -1; + *n = mem[t]; + if (*n < 0 || *n > 64 || (uint64_t)(t + 1 + 2 * *n) > words) return -1; + for (i = 0; i < *n; i++) { + int64_t a = mem[t + 1 + 2 * i], w = mem[t + 2 + 2 * i]; + if (a <= 0 || w <= 0 || (uint64_t)(a + w) > words) return -1; + } + return t; +} +static void hold_copy(int64_t *mem, int64_t t, int64_t n, int rank, int in) +{ + int64_t i, k, c = hold_base[rank]; + for (i = 0; i < n; i++) { + int64_t a = mem[t + 1 + 2 * i], w = mem[t + 2 + 2 * i]; + for (k = 0; k < w; k++, c++) { if (in) mem[a + k] = hold_cells[c]; else hold_cells[c] = mem[a + k]; } + } +} +/* op 57: 0, or -1 (bad block), or -2 (taken out of rank order; the caller stops) */ +static int64_t hold_enter(int64_t *mem, uint64_t words, int64_t rank, int64_t desc) +{ + int64_t t, n, i, total = 0; + if (rank <= 0 || rank >= HOLD_BLOCKS) return -1; + if (hold_depth[rank]) { hold_depth[rank]++; return 0; } + if (hold_top > rank) return -2; + t = hold_table(mem, words, desc, &n); if (t < 0) return -1; + for (i = 0; i < n; i++) total += mem[t + 2 + 2 * i]; +#ifdef HOLD_THREADS + pthread_once(&hold_once, hold_init); + pthread_mutex_lock(&hold_lock[rank]); + pthread_mutex_lock(&hold_meta); +#endif + if (!hold_ready[rank]) { /* the first entry anywhere: the image's initial values become the shared ones */ + if (hold_next + total > HOLD_CELLS) { +#ifdef HOLD_THREADS + pthread_mutex_unlock(&hold_meta); pthread_mutex_unlock(&hold_lock[rank]); +#endif + return -1; + } + hold_base[rank] = hold_next; hold_size[rank] = (int)total; hold_next += (int)total; hold_ready[rank] = 1; + hold_copy(mem, t, n, (int)rank, 0); + } +#ifdef HOLD_THREADS + pthread_mutex_unlock(&hold_meta); +#endif + hold_copy(mem, t, n, (int)rank, 1); + hold_depth[rank] = 1; hold_order[hold_n++] = (unsigned char)rank; hold_top = (int)rank; + return 0; +} +/* op 58 */ +static int64_t hold_leave(int64_t *mem, uint64_t words, int64_t rank, int64_t desc) +{ + int64_t t, n; + if (rank <= 0 || rank >= HOLD_BLOCKS || !hold_depth[rank]) return -1; + if (--hold_depth[rank]) return 0; + t = hold_table(mem, words, desc, &n); + if (t >= 0) hold_copy(mem, t, n, (int)rank, 0); + if (hold_n > 0 && hold_order[hold_n - 1] == rank) hold_n--; + hold_top = hold_n ? hold_order[hold_n - 1] : 0; +#ifdef HOLD_THREADS + pthread_mutex_unlock(&hold_lock[rank]); +#endif + return 0; +} +/* a machine that ends while inside blocks gives them up, without writing back */ +static void hold_release_all(void) +{ + while (hold_n > 0) { + int r = hold_order[--hold_n]; + hold_depth[r] = 0; +#ifdef HOLD_THREADS + pthread_mutex_unlock(&hold_lock[r]); +#endif + } + hold_top = 0; +} +#endif diff --git a/src/micro/micro.c b/src/micro/micro.c index 9924d5e..e095451 100644 --- a/src/micro/micro.c +++ b/src/micro/micro.c @@ -34,6 +34,10 @@ #include "micro_port.h" #include "fops.h" #include "bops.h" +#ifdef ZY_THREADS +#define HOLD_THREADS +#endif +#include "hold.h" #define NENH 512 #define XOP0 22 #define XPOOL 4096 @@ -537,6 +541,11 @@ static int run_from(int p, int s, int r) /* poll: a streaming port suspends once, so its host can deliver input that is waiting */ result = micro_syscall(m, b, 0, 0, 0); if (result == MICRO_WAIT) { sus_p = p - 1; sus_s = s; sus_r = r; return MICRO_SUSPENDED; } + } else if (b == 57) { + result = hold_enter(m, mw, m[a + 1], m[a + 2]); + if (result == -2) { micro_msg("zy: a hold block was entered while a later one was held; hold blocks are entered in the order they are declared\n"); context_call(7, 2, 0, 0, s + 2, r); return 1; } /* a trap: exit status 2 */ + } else if (b == 58) { + result = hold_leave(m, mw, m[a + 1], m[a + 2]); } else result = context_call(b, m[a + 1], m[a + 2], m[a + 3], s + 2, r); m[a] = result; s += 2; @@ -718,7 +727,7 @@ static void *context_worker(void *opaque) { if (!context->requested_exit) context->exit_code = context_cancelled() ? 0 : result ? -1 : inmem(final_s) ? (int)m[final_s] : 0; context_close(context->worker_channel.handle); while (context_children) context_join(context_children->token, 1); - micro_context_port_free(); m = 0; atomic_fetch_sub(&context_memory_live, 1); context_current = 0; return 0; + hold_release_all(); micro_context_port_free(); m = 0; atomic_fetch_sub(&context_memory_live, 1); context_current = 0; return 0; } static Cell context_start(Cell entry, Cell channel, int sp, int rp) { if (!inmem(entry) || !inmem(channel) || (entry >= HEAP_LO && (!inmem(entry - 3) || m[entry - 3] != (entry ^ 0x2B7E1516)))) return -1; -- cgit v1.2.3