Hojun-Cho
5609d0456f
Subsumes #36. Drop wwstage scanlocals pre-pass; both stages converge on first-use+fail-loud frame growth, rule-10 polarity DOWN to leaner side. #36's surfaces (frame-total divergence on match-arm case-let; sibling offset divergence in variadic+iter+match-prev compositions) close naturally — running-max c.frame includes every first-use binding. selfhost/cmd/wcc: add atlocals persistent @-prefix registry surviving cgblock save/restore; add cgoutbuf/cgoutmode/cgout_enable/disable/flush for deferred prologue (emit body to buffer, finalise c.frame, then TEXT/SUBQ + flush); localadd @-prefix dedups against atlocals + fail-louds on size-grow (rule 7 — no silent truncate); cgreturn-tagged routes through @retscr (was colliding with @tagscr on arg-widen sizes); variadic gather esz uses raw primsize (rune->4) not slotsize (rune->8) — matches cstage and fixes the #36 sibling runtime miscompile in non-leaf variadic+iter+match-prev callees. cmd/w6c/cgen.c: drop the over-allocation hack ("for byte-id with wwstage scanlocals reservation") since wwstage no longer over-reserves; add fail-loud on @sretscr size-grow; @tagscr sites pass actual slot_sz instead of stale c.tagscrsz. 748_size_strategy_convergence: table-driven 4 rows x 2 stages (tag_variadic_runearm, trim_iter_match_prev, variadic_gather_rune_stride, leaf_baseline). Each exercises a #36 surface shape; 8/8 ok. Net -1565 lines. Sister latents filed as cosmetic (cs/ws frame size drift on multiple-variadic-call fns): labelseq drift + varargseq stuck at 0 — both bootstrap-byte-id safe (ww2==ww3==ww4 holds since both ww2 and ww3 are wwstage outputs). make test 122/122; ww2==ww3==ww4 byte-id holds via 995_self_rebuild.
453 lines
13 KiB
Plaintext
453 lines
13 KiB
Plaintext
// selfhost/cmd/wcc/cgendecl.ww — split out of cgen.ww.
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//
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// Houses the top-level emission glue:
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// - cgfnparams: parameter spilling per SysV
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// - cgfn: fn body emit (TEXT/SUBQ patched after body), prologue
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// deferred via cgen.ww's cgoutbuf so the frame size
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// reflects every emit-time localadd (#15/#26c)
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// - cgfile: file-level entry (the exported driver)
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//
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// Bundler pulls this in transitively via cgen.ww; consumers don't
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// need to `use cgendecl;` directly.
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package wcc;
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import os;
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import mem;
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import ast;
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import tok;
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import typ;
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import sym;
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import strconv;
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// ---- function-level cgen ---------------------------------------------
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fn cgfnparams(c: *cgen, params: *node) void = {
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let p: *node = params;
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// sret (#23): RDI is consumed by the hidden dest pointer
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// (already spilled to @sretarg by cgfn); the first user param
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// lands in SI.
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let idx: i32 = 0;
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if (localfind(c, "@sretarg") != 0) { idx = 1; };
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let fidx: i32 = 0;
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// Cursor for args that overflow the SysV reg windows. Each
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// stack-passed arg lives at 16+8*k(BP) — no spill, the local
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// is registered with a *positive* offset pointing into the
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// caller's frame. Mirrors C cgen's cg_stack_arg_cursor.
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let stkcursor: i32 = 0;
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for (p != nil) {
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if (p.kind == nkind.N_PARAM) {
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let nm: str = p.str;
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// Hare-style variadic `T...`: callee receives a []T
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// slice (3 register words / 24B). Mirror the slice-
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// param spill below but use a synthesised TSLICE
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// tnode so body references see the slot as a slice.
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if (p.op == tkind.TK_ELLIPSIS) {
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let tn: *node = slicewrap(c, p.lhs);
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if (idx + 3 <= 6) {
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let off: i32 = localadd(c, nm, 24, tn);
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emitline("\tMOVQ\t");
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emitline(argregname(idx));
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emitline(", ");
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emitoff(off: i64);
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emitline("(BP)\n");
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idx += 1;
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emitline("\tMOVQ\t");
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emitline(argregname(idx));
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emitline(", ");
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emitoff((off + 8): i64);
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emitline("(BP)\n");
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idx += 1;
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emitline("\tMOVQ\t");
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emitline(argregname(idx));
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emitline(", ");
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emitoff((off + 16): i64);
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emitline("(BP)\n");
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idx += 1;
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} else { if (idx < 6) {
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// Partial-fit stitch — variadic `T...` is a slice
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// at the ABI boundary (the call site synthesises a
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// 24B descriptor and pushes ptr/len/cap), so this
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// mirrors the slice branch at cgendecl.ww:518.
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let off: i32 = localadd(c, nm, 24, tn);
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let regs_left: i32 = 6 - idx;
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let w: i32 = 0;
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for (w < regs_left) {
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emitline("\tMOVQ\t");
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emitline(argregname(idx));
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emitline(", ");
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emitoff((off + w*8): i64);
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emitline("(BP)\n");
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idx += 1;
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w += 1;
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};
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for (w < 3) {
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emitline("\tMOVQ\t");
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emitoff((16 + stkcursor*8): i64);
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emitline("(BP), AX\n");
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emitline("\tMOVQ\tAX, ");
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emitoff((off + w*8): i64);
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emitline("(BP)\n");
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stkcursor += 1;
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w += 1;
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};
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} else {
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localaddstack(c, nm, tn, 16 + stkcursor*8);
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stkcursor += 3;
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};};
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p = p.next;
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continue;
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};
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if (isfloattype(c, p.lhs)) {
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// Float param: SysV uses the XMM stream
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// (X0..X7). 8B (f64) or 4B (f32) slot.
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let fsz: i32 = 8;
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if (isf32type(c, p.lhs)) { fsz = 4; };
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if (fidx < 8) {
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let off: i32 = localadd(c, nm, fsz, p.lhs);
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let mov: str = "MOVSD";
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if (fsz == 4) { mov = "MOVSS"; };
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emitline("\t");
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emitline(mov);
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emitline("\t");
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emitline(fargregname(fidx));
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emitline(", ");
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emitoff(off: i64);
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emitline("(BP)\n");
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fidx += 1;
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} else {
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localaddstack(c, nm, p.lhs, 16 + stkcursor*8);
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stkcursor += 1;
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};
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p = p.next;
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continue;
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};
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if (istaggedtype(c, p.lhs)) {
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let slot: i32 = slotsize(c, p.lhs);
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let nw: i32 = slot / 8;
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if (idx + nw <= 6) {
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let off: i32 = localadd(c, nm, slot, p.lhs);
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let w: i32 = 0;
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for (w < nw) {
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emitline("\tMOVQ\t");
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emitline(argregname(idx));
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emitline(", ");
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emitoff((off + w*8): i64);
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emitline("(BP)\n");
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idx += 1;
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w += 1;
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};
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} else { if (idx < 6 && nw > 1) {
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// Partial fit: fill remaining regs, then read
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// the tail from positive BP offsets. Mirrors
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// the caller's greedy reg fill in pushargsrev.
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let off: i32 = localadd(c, nm, slot, p.lhs);
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let regs_left: i32 = 6 - idx;
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let w: i32 = 0;
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for (w < regs_left) {
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emitline("\tMOVQ\t");
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emitline(argregname(idx));
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emitline(", ");
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emitoff((off + w*8): i64);
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emitline("(BP)\n");
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idx += 1;
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w += 1;
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};
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for (w < nw) {
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emitline("\tMOVQ\t");
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emitoff((16 + stkcursor*8): i64);
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emitline("(BP), AX\n");
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emitline("\tMOVQ\tAX, ");
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emitoff((off + w*8): i64);
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emitline("(BP)\n");
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stkcursor += 1;
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w += 1;
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};
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} else {
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localaddstack(c, nm, p.lhs, 16 + stkcursor*8);
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stkcursor += nw;
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};};
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} else { if (isslicetype(c, p.lhs)) {
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if (idx + 3 <= 6) {
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let off: i32 = localadd(c, nm, 24, p.lhs);
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emitline("\tMOVQ\t");
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emitline(argregname(idx));
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emitline(", ");
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emitoff(off: i64);
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emitline("(BP)\n");
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idx += 1;
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emitline("\tMOVQ\t");
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emitline(argregname(idx));
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emitline(", ");
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emitoff((off + 8): i64);
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emitline("(BP)\n");
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idx += 1;
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emitline("\tMOVQ\t");
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emitline(argregname(idx));
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emitline(", ");
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emitoff((off + 16): i64);
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emitline("(BP)\n");
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idx += 1;
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} else { if (idx < 6) {
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// Partial-fit stitch — mirrors tagged at lines
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// 440-469. Caller's pushargsrev greedy-fills the
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// remaining argregs (ptr,len,cap order), the tail
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// spills to +16+stkcursor*8(BP).
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let off: i32 = localadd(c, nm, 24, p.lhs);
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let regs_left: i32 = 6 - idx;
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let w: i32 = 0;
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for (w < regs_left) {
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emitline("\tMOVQ\t");
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emitline(argregname(idx));
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emitline(", ");
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emitoff((off + w*8): i64);
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emitline("(BP)\n");
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idx += 1;
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w += 1;
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};
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for (w < 3) {
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emitline("\tMOVQ\t");
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emitoff((16 + stkcursor*8): i64);
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emitline("(BP), AX\n");
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emitline("\tMOVQ\tAX, ");
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emitoff((off + w*8): i64);
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emitline("(BP)\n");
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stkcursor += 1;
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w += 1;
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};
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} else {
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localaddstack(c, nm, p.lhs, 16 + stkcursor*8);
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stkcursor += 3;
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};};
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} else { if (isstrtype(c, p.lhs)) {
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if (idx + 2 <= 6) {
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let off: i32 = localadd(c, nm, 16, p.lhs);
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emitline("\tMOVQ\t");
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emitline(argregname(idx));
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emitline(", ");
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emitoff(off: i64);
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emitline("(BP)\n");
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idx += 1;
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emitline("\tMOVQ\t");
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emitline(argregname(idx));
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emitline(", ");
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emitoff((off + 8): i64);
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emitline("(BP)\n");
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idx += 1;
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} else { if (idx < 6) {
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// Partial-fit stitch — mirrors tagged at lines
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// 440-469. Only idx=5 hits this (nw=2,
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// regs_left=1): ptr lands in R9, len at
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// +16+stkcursor*8(BP).
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let off: i32 = localadd(c, nm, 16, p.lhs);
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let regs_left: i32 = 6 - idx;
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let w: i32 = 0;
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for (w < regs_left) {
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emitline("\tMOVQ\t");
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emitline(argregname(idx));
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emitline(", ");
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emitoff((off + w*8): i64);
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emitline("(BP)\n");
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idx += 1;
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w += 1;
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};
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for (w < 2) {
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emitline("\tMOVQ\t");
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emitoff((16 + stkcursor*8): i64);
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emitline("(BP), AX\n");
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emitline("\tMOVQ\tAX, ");
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emitoff((off + w*8): i64);
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emitline("(BP)\n");
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stkcursor += 1;
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w += 1;
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};
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} else {
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localaddstack(c, nm, p.lhs, 16 + stkcursor*8);
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stkcursor += 2;
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};};
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} else { let stsz: i32 = structparamsize(c, p.lhs);
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if (stsz > 0) {
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// User-defined by-value struct ≤ 16B: 1 or 2
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// integer eightbytes. Mirrors cstage's
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// `struct_eb = (pu->size > 8) ? 2 : 1` and the
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// matching reg/stack/stitch arms in cgen.c cgfn.
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let nw: i32 = 1;
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if (stsz > 8) { nw = 2; };
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if (idx + nw <= 6) {
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let off: i32 = localadd(c, nm, stsz, p.lhs);
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let w: i32 = 0;
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for (w < nw) {
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emitline("\tMOVQ\t");
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emitline(argregname(idx));
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emitline(", ");
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emitoff((off + w*8): i64);
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emitline("(BP)\n");
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idx += 1;
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w += 1;
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};
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} else { if (idx < 6 && nw > 1) {
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let off: i32 = localadd(c, nm, stsz, p.lhs);
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let regs_left: i32 = 6 - idx;
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let w: i32 = 0;
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for (w < regs_left) {
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emitline("\tMOVQ\t");
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emitline(argregname(idx));
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emitline(", ");
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emitoff((off + w*8): i64);
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emitline("(BP)\n");
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idx += 1;
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w += 1;
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};
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for (w < nw) {
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emitline("\tMOVQ\t");
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emitoff((16 + stkcursor*8): i64);
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emitline("(BP), AX\n");
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emitline("\tMOVQ\tAX, ");
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emitoff((off + w*8): i64);
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emitline("(BP)\n");
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stkcursor += 1;
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w += 1;
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};
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} else {
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localaddstack(c, nm, p.lhs, 16 + stkcursor*8);
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stkcursor += nw;
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};};
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} else {
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if (idx < 6) {
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let off: i32 = localadd(c, nm, 8, p.lhs);
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emitline("\tMOVQ\t");
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emitline(argregname(idx));
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emitline(", ");
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emitoff(off: i64);
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emitline("(BP)\n");
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idx += 1;
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} else {
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localaddstack(c, nm, p.lhs, 16 + stkcursor*8);
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stkcursor += 1;
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};
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};
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};};};
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};
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p = p.next;
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};
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};
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fn cgfn(c: *cgen, fn_: *node) void = {
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cgeninit(c, c.a);
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c.fnname = fn_.str;
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c.curmod = fn_.nmod;
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c.fnret = fn_.lhs;
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// sret callee (#23): return type is plain TY_STRUCT > 24B.
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// Reserve 8B for @sretarg (holds the saved hidden RDI dest
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// pointer); cgfnparams skips DI for user args, cgreturn writes
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// through *(@sretarg) and returns @sretarg in RAX.
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let sret_callee: bool = sretretsize(c, c.fnret) > 0;
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// Capture the body into cgoutbuf while c.frame grows under
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// emit-time localadd calls (#15/#26c — wwstage dropped its
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// scanlocals pre-pass to align DOWN with cstage's first-use
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// pattern). The prologue (TEXT label, PUSHQ/MOVQ/SUBQ) emits
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// after the body finishes so the frame size reflects every
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// localadd. Mirrors cstage cmd/w6c/cgen.c cgfn which builds
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// `subsp`/`text` Progs up front and patches their `from.offset`
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// at the end via txt_emit.
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cgout_enable(c.a);
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if (sret_callee) {
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let saoff: i32 = localadd(c, "@sretarg", 8, nil);
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emitline("\tMOVQ\tDI, ");
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emitoff(saoff: i64);
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emitline("(BP)\n");
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};
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cgfnparams(c, fn_.list);
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c.lastwasreturn = 0;
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// Iterate the fn body's statements directly rather than dispatching
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// the outermost N_BLOCK through cgstmt — cgblock now save/restores
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// c.locals to scope inner shadows (post-#27), but the function body
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// is not "an inner block": defers (queued during the body) and the
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// implicit-return epilogue both call cgexpr after this loop and
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// resolve identifiers via localfind, so the body's locals must
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// still be in c.locals when we get there.
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if (fn_.body != nil) {
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if (fn_.body.kind == nkind.N_BLOCK) {
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let s: *node = fn_.body.list;
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for (s != nil) {
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cgstmt(c, s);
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s = s.next;
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};
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} else {
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cgstmt(c, fn_.body);
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};
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};
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if (c.lastwasreturn == 0) {
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// Run any registered defers in LIFO order before the
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// implicit return.
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rundefers(c);
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// Zero AX before the fall-through return — matches cstage,
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// which always emits this so void-returning fns don't leak
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// a stale callee value to their caller.
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emitline("\tMOVQ\t$0, AX\n");
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emitline("\tMOVQ\tBP, SP\n");
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emitline("\tPOPQ\tBP\n");
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emitline("\tRET\n");
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};
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cgout_disable();
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let frame: i32 = c.frame;
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if ((frame & 15) != 0) { frame = (frame + 15) & ~15; };
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// Emit the TEXT label via emitfnname so the def site picks up the
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// same skip rule (FFI / `main` / empty-module) and the same module
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// hint (this fn's own module) that the call sites use.
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emitline("TEXT ");
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emitfnname(c, fn_.str, fn_.nmod);
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emitline(",$");
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emitint(frame: i64);
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emitline("\n");
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emitline("\tPUSHQ\tBP\n");
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emitline("\tMOVQ\tSP, BP\n");
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emitline("\tSUBQ\t$");
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emitint(frame: i64);
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emitline(", SP\n");
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cgout_flush();
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};
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// ---- file-level entry ------------------------------------------------
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export fn cgfile(c: *cgen, file: *node) void = {
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if (file == nil) { return; };
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c.strlits = nil;
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c.strlitseq = 0;
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collectaliases(c, file);
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// Enums must register before structs — fieldsize on a tkind-typed
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// field needs the enum's storage size, otherwise it falls back to
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// 8 (wrong load width).
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collectenums(c, file);
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collectstructs(c, file);
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collectdefs(c, file);
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collectfnrets(c, file);
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fficollect(c, file);
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collectmods(c, file);
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collectlets(c, file);
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let d: *node = file.list;
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for (d != nil) {
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if (d.kind == nkind.N_FNDECL) {
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if (d.body != nil) {
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cgfn(c, d);
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};
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};
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d = d.next;
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};
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letpreintern(c, file);
|
|
emitdatasection(c);
|
|
emitdefconstants(c, file);
|
|
emitletdataw(c, file);
|
|
};
|