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-rw-r--r--src/compiler/analyzer.zc5
-rw-r--r--src/compiler/base.zc5
-rw-r--r--src/compiler/builtins.zc93
-rw-r--r--src/compiler/expr.zc18
-rw-r--r--src/compiler/stmt.zc10
5 files changed, 125 insertions, 6 deletions
diff --git a/src/compiler/analyzer.zc b/src/compiler/analyzer.zc
index d1f6f3d..34c0a8b 100644
--- a/src/compiler/analyzer.zc
+++ b/src/compiler/analyzer.zc
@@ -389,6 +389,7 @@ int newloc(int n) {
if (if_local) if_local[i] = 0;
if (!local_origin_mask) local_origin_mask = chk_resize(0, 0, loccap); local_origin_mask[i] = 0;
if (!local_cell) local_cell = chk_resize(0, 0, loccap); local_cell[i] = 0;
+ if (!local_dropset) local_dropset = chk_resize(0, 0, loccap); local_dropset[i] = 0;
if (!local_captured) local_captured = chk_resize(0, 0, loccap); local_captured[i] = 0;
if (!local_ended) local_ended = chk_resize(0, 0, loccap); local_ended[i] = 0;
if (!local_end_info) local_end_info = chk_resize(0, 0, loccap); local_end_info[i] = 0;
@@ -920,6 +921,7 @@ int touch(int i) {
// an expression of class c used as a plain value (a lend, an operand). a new
// object can't be used that way, since nothing would own it.
int plainuse(int c) {
+ if (c == C_FRESH && drop_tail == here && fchk && infn) { drop_temporary(); return C_PLAIN; }
if (c == C_FRESH) cerr("a new object can't be used as a plain value; bind it to a name first");
if (c >= C_VAR) touch(c - C_VAR);
return C_PLAIN;
@@ -933,6 +935,7 @@ int szclass(int n) {
// freeing an owned local. one that holds a typed object with no pointer
// fields goes back through recycle_leaf, which knows its class
int freevar(int i) {
+ if (o3on && fchk && ldroppable(i)) cerrn(i, "has drop and can't end inside an o3 region");
if (local_captured && local_captured[i]) { lit(0); laddr(lslot[i]); op(O_ST); return 0; }
vaddr(i); op(O_LD);
if (lleaf[i] && !o3on && !dry && lookup(s_recycle_leaf) >= 0) {
@@ -966,7 +969,7 @@ int exit_vars(int dep, int final) {
// block ends.
int unused_check(int from) {
while (from < nloc) {
- if (fchk && lown[from] && !lused[from] && !(lrskind[from] == RS_PARAM && rt.eq_w(lname[from], "_"))) serrn(lname[from], "owned object is never used");
+ if (fchk && lown[from] && !lused[from] && !ldroppable(from) && !(lrskind[from] == RS_PARAM && rt.eq_w(lname[from], "_"))) serrn(lname[from], "owned object is never used");
from++;
}
return 0;
diff --git a/src/compiler/base.zc b/src/compiler/base.zc
index b326c80..88708f0 100644
--- a/src/compiler/base.zc
+++ b/src/compiler/base.zc
@@ -255,6 +255,10 @@ int fn_return_type; // a consistent return type inferred from the function body
const int EF_READ = 1, EF_WRITE = 2, EF_RETAIN = 4, EF_CONSUME = 8, EF_UNKNOWN = 16, EF_ALIAS = 32, EF_IDENTITY = 64;
word effect_symbols, effect_edges, effect_requirements, effect_current; int effect_floor, effect_argument_base;
word local_origin, local_origin_mask, local_cell, local_captured, local_ended, local_end_info; word effect_value, argorigin_mask; int capture_enabled; word[1] capture_dummy;
+// drops (docs/design/destructors.md): the code position just past a drop form (a fresh
+// value with a drop still on the stack there), the type `this` gets in the next closure,
+// a local whose drop is set, a mailbox send whose arguments are checked, and o3 block depth.
+int drop_tail = -1, send_check, o3blk; word closure_this, local_dropset;
int borrow_pending, borrow_depth, borrow_jump = -1, borrow_entry; word borrow_slots;
int argorigin = -1, argtemporary, argowner = -1; word argowner_fact;
int stubgen; // 1 while an extern's generated stub is compiled: the stub gets no hints
@@ -748,6 +752,7 @@ int reserve_locals(int need) {
if (local_origin) local_origin = chk_resize(local_origin, nloc, cap);
if (local_origin_mask) local_origin_mask = chk_resize(local_origin_mask, nloc, cap);
if (local_cell) local_cell = chk_resize(local_cell, nloc, cap);
+ if (local_dropset) local_dropset = chk_resize(local_dropset, nloc, cap);
if (local_captured) local_captured = chk_resize(local_captured, nloc, cap);
if (local_ended) local_ended = chk_resize(local_ended, nloc, cap);
if (local_end_info) local_end_info = chk_resize(local_end_info, nloc, cap);
diff --git a/src/compiler/builtins.zc b/src/compiler/builtins.zc
index 5efe379..8c00636 100644
--- a/src/compiler/builtins.zc
+++ b/src/compiler/builtins.zc
@@ -838,6 +838,99 @@ int array_member(int c, int n) {
if (n == intern("pop")) return array_pop(t);
return array_resize(t);
}
+// ---- drops and heap() (docs/design/destructors.md) ----
+
+// a pointer to a struct whose body declares drop: its values drop through the type
+int tdroppable(word t) {
+ word e;
+ if (!t || !isptr(t)) return 0;
+ e = t[4];
+ return e[0] == TY_STRUCT && e[3] >= 0 && methof(e, intern("drop")) >= 0;
+}
+// local i holds a value with a drop: one set on it, or one its type declares
+int ldroppable(int i) { return (local_dropset && local_dropset[i]) || tdroppable(ltype[i]); }
+// entering o3 from normal code: the collector waits until the outermost region is left
+int o3_enter_code() { callname(intern("rt.o3_enter")); op(O_DROP); return 0; }
+// a fresh value with a drop that nothing holds: it is held in a hidden slot and
+// dropped when the full statement ends
+int drop_temporary() {
+ emit_borrow_hold();
+ if (hint_begin(tpack(), HINT_SMALL)) { rt.put_s("value with drop is never bound; it drops at the end of this statement"); dg_close(); }
+ return 0;
+}
+// the value is on the stack. compile the drop (the next expression, usually fn() { ... }
+// with this bound to the value), attach it with rt.set_drop, and leave the value there
+// with the class and facts it had. owner is the local that owns the value, or -1.
+int drop_attach(word vty, int owner) {
+ word t = xty, af = xaf, ev = effect_value; int bor = xbor, st = xstr, c;
+ if (o3on) serr("a drop can't be set inside an o3 region");
+ if (owner >= 0 && fchk && local_dropset) {
+ if (local_dropset[owner]) cerrn(owner, "drop is already set");
+ local_dropset[owner] = 1;
+ }
+ lit(0); op(O_PICK);
+ closure_this = vty; c = expr(); rval(); closure_this = 0;
+ if (c >= C_VAR) touch(c - C_VAR);
+ callname(intern("rt.set_drop")); op(O_DROP);
+ xty = t; xaf = af; effect_value = ev; xbor = bor; xstr = st;
+ lv = 0; lvk = LV_NONE; xzero = 0; xconst = 0; xfloat = 0;
+ return 0;
+}
+// drop(v, fn() { ... }): v, with the drop attached
+int drop_call() {
+ int c, prior = 0, i = 0 - 1;
+ next(); expect(s_lp);
+ if (tk == T_ID) { peek(); if (pk_tk == T_OP && (pk_tv == s_comma)) { i = findloc(tv); if (i >= 0) prior = ltag[i] & LREAD; } }
+ c = expr(); rval();
+ i = 0 - 1;
+ if (c >= C_VAR) i = lroot(c - C_VAR);
+ if (i >= 0 && prior && fchk) cerrn(i, "drop set after the value was used");
+ tcneed(isptr(xty) || xty == tword, "drop needs a heap value", xty);
+ expect(s_comma);
+ drop_attach(xty, i);
+ expect(s_rp);
+ if (c == C_FRESH) drop_tail = here;
+ return c;
+}
+// v.drop(fn() { ... }) gives v back; v.drop = fn() { ... }; is a statement
+int drop_member(int c, word borrowed) {
+ int prior = 0, i = 0 - 1, assign = is_op(s_eq);
+ if (lv && lvk == LV_LOCAL) prior = ltag[lvi] & LREAD;
+ rval();
+ xaf = borrowed;
+ if (c >= C_VAR) { i = lroot(c - C_VAR); touch(c - C_VAR); }
+ if (i >= 0 && prior && fchk) cerrn(i, "drop set after the value was used");
+ next();
+ if (assign && c == C_FRESH && fchk && infn) { drop_temporary(); c = C_PLAIN; }
+ drop_attach(xty, i);
+ if (!assign) expect(s_rp);
+ if (c == C_FRESH) drop_tail = here;
+ if (assign) { xty = tint; xaf = 0; xbor = 0 - 1; return C_PLAIN; }
+ return c;
+}
+// heap(v): v copied into a fresh owned block sized to it
+int heap_box() {
+ int c, place = tpack(), ms; word t;
+ next(); expect(s_lp);
+ c = expr(); rval(); plainuse(c);
+ expect(s_rp);
+ t = xty;
+ stamp_site();
+ if (isagg(t)) {
+ lit(tsz(t)); lit(t); callname(intern("rt.heap_copy"));
+ newsz = tsz(t); xty = tptr(t);
+ if (t[0] == TY_STRUCT) { ms = methof(t, intern("drop")); if (ms >= 0) { fnref(ms); callname(intern("rt.set_tdrop")); } }
+ } else if (isptr(t) && t[4][0] == TY_CHAR) {
+ callname(intern("rt.heap_s")); newsz = -1; xty = t;
+ } else {
+ if (xfloat) xfloat = 0;
+ lit(t); callname(intern("rt.heap_w")); newsz = 1; xty = tptr(t);
+ }
+ newleaf = 0;
+ xaf = af_new(newsz, 2, place);
+ lv = 0; lvk = LV_NONE; xzero = 0; xconst = 0; xstr = 0; xbor = 0 - 1; effect_value = 0;
+ return C_FRESH;
+}
// compile sizeof(T) or sizeof(e): the size of a type or expression in words.
int kw_sizeof() {
int t;
diff --git a/src/compiler/expr.zc b/src/compiler/expr.zc
index 8768658..e6acfc8 100644
--- a/src/compiler/expr.zc
+++ b/src/compiler/expr.zc
@@ -68,6 +68,7 @@ int args(int tags, word ft, int bs, int fat) {
freeing = sname[cs] == s_free || sname[cs] == s_recycle;
harmless = sname[cs] == s_put_s || rt.eq_w(sname[cs], "rt.put_n") || rt.eq_w(sname[cs], "rt.put_c") || rt.eq_w(sname[cs], "len") || rt.eq_w(sname[cs], "cap");
}
+ int sending = send_check; send_check = 0;
xgive = 0; ifcall = 0 - 1; effect_argument_base = 0;
expect(s_lp);
if (!is_op(s_rp)) {
@@ -76,6 +77,10 @@ int args(int tags, word ft, int bs, int fat) {
closure_expected = 0;
if (ft && np + parameter_base < ft[3] && is_id(s_fn)) closure_expected = subst(ft[7 + np + parameter_base], bs);
place = tpack(); c = expr(); rval(); closure_expected = expected;
+ if (sending && fchk && ((c >= C_VAR && ldroppable(lroot(c - C_VAR))) || tdroppable(xty) || (c == C_FRESH && drop_tail == here))) {
+ if (c >= C_VAR) serrn(lname[lroot(c - C_VAR)], "has drop and can't be copied into a message"); else serr("a value with drop can't be copied into a message");
+ }
+ if (freeing && o3on && fchk && c >= C_VAR && ldroppable(lroot(c - C_VAR))) serrn(lname[lroot(c - C_VAR)], "has drop and can't end inside an o3 region");
current = effect_origin(c); current_mask = effect_mask(c); origins = origins | current_mask; effect_args_mask(cs, np + parameter_base, current_mask);
if (!np) origin = current; else if (origin != current) origin = -1;
tag = (tags >> (np + np)) & 3;
@@ -176,6 +181,7 @@ int newtyped() {
expect(s_rp);
stamp_site();
if (fast) callname(s_new_k); else callname(s_new_t); vf_effect();
+ if (t[0] == TY_STRUCT && t[3] >= 0) { int dm = methof(t, intern("drop")); if (dm >= 0) { fnref(dm); callname(intern("rt.set_tdrop")); } }
xaf = af_new(length, 2, place);
lv = 0; lvk = LV_NONE; xty = tptr(t); xzero = 0; xstamp = 1;
return C_FRESH;
@@ -462,6 +468,7 @@ int call(int s) {
}
if (!(sflag[s] & F_DEF) || s == finsym) sflag[s] = sflag[s] | F_EARLY; // called before its body: an owned return is not inferred for it
if (sflag[s] & F_EXT) { lit(sval[s][-1]); op(620); } // an extern: the native call opcode, with the block's address
+ else if (!o3on && (sflag[s] & F_O3)) { o3_enter_code(); fnref(s); op(O_CALL); callname(intern("rt.o3_leave")); op(O_DROP); } // into o3 from normal code: no collection until it returns
else { fnref(s); op(O_CALL); }
if (!o3on && (sflag[s] & F_O3) && ft) { // non-o3 called o3: fatten the result here, not inside the callee
rhs_type = subst(ft[4], bs);
@@ -649,14 +656,18 @@ word closure_layout(int closure_index, int count) {
int closure() {
char* xcf;
int np = 0; char*[24] pn; word[24] pty; int hop, entry, i, t, envl, ncap, c, result, declared = 0, tags = 0, tag, lt, lfl = tline; word[24] ptags;
- word expected = closure_expected; closure_expected = 0;
+ word expected = closure_expected, this_type = closure_this; closure_expected = 0; closure_this = 0;
reserve_closures(nclo + 1);
if (o3on) serr("closures can't be made inside an o3 region");
next();
// fn:type(args) names the result; returns are coerced and checked against it
if (accept(s_colon)) declared = ptype0();
expect(s_lp);
- if (!is_op(s_rp)) {
+ if (this_type) { // a drop: fn() { ... } gets the value as this, borrowed
+ pn[0] = s_this; pty[0] = this_type; ptags[0] = 1; pnoffs[0] = toff; pnplaces[0] = tpack(); np = 1;
+ if (!is_op(s_rp)) serr("a drop takes no parameters; the value is this");
+ }
+ if (!is_op(s_rp) && !this_type) {
while (1) {
pty[np] = tword;
if (expected && expected[0] == TY_FN && np < expected[3]) pty[np] = expected[7 + np];
@@ -1022,6 +1033,7 @@ int primary() {
// wins over a global (a top-level function or constant) of the same name
if (mstruct && !ginst) { ms = lookup(methname(mstruct, n)); if (ms >= 0 && (skind[ms] == K_CONST || (skind[ms] == K_FN && (sflag[ms] & F_STATIC)))) s = ms; }
if (s < 0 && rt.eq_w(n, "new")) s = source_lookup(s_new);
+ if (s < 0 && (rt.eq_w(n, "heap") || rt.eq_w(n, "drop"))) { peek(); if (pk_tk == T_OP && pk_tv == s_lp) { if (rt.eq_w(n, "heap")) return heap_box(); return drop_call(); } }
if (s >= 0) rs_put(toff, RS_SYM, rs_sym(s), s);
if (s >= 0 && skind[s] == K_KW) {
if (!(sflag[s] & F_EXPR)) dien(n, "can't be used inside an expression");
@@ -1185,6 +1197,8 @@ word field(int c) {
}
fieldpos = tpack(); n = name(); fieldoff = nameoff;
st = xty;
+ if (rt.eq_w(n, "drop") && (is_op(s_lp) || is_op(s_eq)) && (isptr(st) || st == tword) && !(isptr(st) && st[4][0] == TY_STRUCT && tfindfield(st[4], n) >= 0)) return drop_member(c, borrowed);
+ if (rt.eq_w(n, "send") && is_op(s_lp) && isptr(st) && st[4][0] == TY_STRUCT && tfindfield(st[4], intern("__mailbox")) >= 0) send_check = 1;
if (st[0] == TY_ARR || st[0] == TY_DYN) {
if (pmatch) probe_member(st);
if (is_op(s_lp) && array_method(n)) { xaf = borrowed; return array_member(c, n); }
diff --git a/src/compiler/stmt.zc b/src/compiler/stmt.zc
index 0182728..6d5abe7 100644
--- a/src/compiler/stmt.zc
+++ b/src/compiler/stmt.zc
@@ -30,7 +30,7 @@ int stmt_inner() {
if (tv == s_semi) { next(); return 0; }
if (tv == s_lb) { block(); return 0; }
}
- c = expr(); rval(); op(O_DROP);
+ c = expr(); rval(); if (c == C_FRESH && drop_tail == here) c = plainuse(c); op(O_DROP);
expect(s_semi);
discard(c);
return 0;
@@ -145,7 +145,7 @@ int localdecl(int typed) {
if (t && t[0] == TY_DYN && is_op(s_lb)) c = array_dynamic_literal(t); else c = expr();
rval(); nomagic = 0; kc = xconst && !xfloat;
if (kc) ltag[i] = ltag[i] | LCONST;
- if (c == C_FRESH) { lnsz[i] = newsz; lleaf[i] = newleaf; }
+ if (c == C_FRESH) { lnsz[i] = newsz; lleaf[i] = newleaf; if (drop_tail == here) local_dropset[i] = 1; }
if (t) fcoerce(t);
vaddr(i);
op(O_ST);
@@ -683,6 +683,7 @@ int kw_return() {
borrow_cleanup();
defer_run(1, 0); // the value is on the stack; the deferred code is stack neutral
exit_vars(1, 0);
+ if (o3blk) { callname(intern("rt.o3_leave")); op(O_DROP); } // a return leaves the o3 block too
epichain = fixnew(here, epichain);
lit(rt.MW - 1); op(O_JMP);
live = 0;
@@ -699,7 +700,9 @@ int kw_o3() {
next();
if (!is_op(s_lb)) { o3one = 1; localdecl(1); o3one = 0; return 0; }
if (o3on || !infn) return block();
+ o3_enter_code();
reserve_code(2); lo = here + 2; lit(lo); op(O_JMP);
+ o3blk++;
o3on = 1; o3reset();
save = nloc; outer = nloc;
i = lbase;
@@ -713,7 +716,7 @@ int kw_o3() {
i++;
}
block();
- o3on = 0;
+ o3on = 0; o3blk--;
if (no3pend >= o3pendcap) { o3pend = chk_resize(o3pend, no3pend * 67, o3pendcap * 2 * 67); o3pendcap = o3pendcap * 2; }
{
p = o3pend + no3pend * 67; p[0] = lo; p[1] = here; p[2] = no3sl;
@@ -733,6 +736,7 @@ int kw_o3() {
}
i++;
}
+ callname(intern("rt.o3_leave")); op(O_DROP);
return 0;
}
// unchecked turns the analyzer off for one statement
generated by cgit v1.2.3 (git 2.39.1) at 2026-10-27 15:47:23 +0000