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cgen: extract the narrow-tail aggregate-register materialise into a shared helper (#14)

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Hojun-Cho
2026-06-28 14:08:57 +09:00
parent ac6e86cefe
commit e7fefa3eb7
4 changed files with 159 additions and 432 deletions
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334
selfhost/cmd/wcc/cgenexpr.ww
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@@ -1721,6 +1721,88 @@ fn aggcopy(c: *cgen, sz: i32) void = {
};
};
// cgaggregstore — ww twin of cstage cgen.c cg_agg_reg_store. The ONE
// register-cursor aggregate materialise: an in-cap (<=24B, GP-class)
// struct/array/tuple already held in the {AX,DX,CX} return cursor is
// stored into basereg+disp. full=sz/8 exact-8B MOVQ words land straight
// in; the sz%8 tail is one sized MOVB/MOVW/MOVL for {1,2,4} (BOTH
// branches). Extracted from the cstage site-E #10 template so every
// narrow-tail materialise funnels through one place — close-by-
// construction (task #14).
//
// dest_padded forks ONLY the {3,5,6,7} tail (no GP sub-register exists
// for those widths and w6a has no shift):
// dest_padded == "the dest is a ceil-8/round8 slot (a scratch, or a
// #75 let/local aggregate slot) so an 8B tail over-store stays
// in-bounds." Post-#9: packed struct fields + array elements => false;
// let/local/scratch slots => true. It CANNOT be derived — paddedness
// is routing knowledge the caller owns.
// true -> a single full MOVQ of the cursor tail eightbyte (= the
// #10 template; the over-store lands in the slot's pad).
// false -> MOVQ the cursor tail eightbyte into the helper's own
// ceil-8 @tagscr pad, then a sized aggcopy of the tail bytes
// into the dest so a packed field / array element is never
// overrun.
// PRECONDITION (caller-owned, stays per-site): the value is already in
// AX/DX/CX, the dest base is resolved into basereg+disp, and the
// float-class (#165) / over-cap-sret (#234) loud-stops have already
// fired. Clobbers SI/BX/AX only on the dest_padded==false detour (the
// value words are in memory by then).
fn cgaggregstore(c: *cgen, basereg: str, disp: i32, sz: i32, dest_padded: bool) void = {
let full: i32 = sz / 8;
let tail: i32 = sz - full * 8;
let i: i32 = 0;
for (i < full) {
let reg: str = "AX";
if (i == 1) { reg = "DX"; };
if (i == 2) { reg = "CX"; };
emitline("\tMOVQ\t");
emitline(reg);
emitline(", ");
emitdispreg((disp + i * 8): i64, basereg);
emitline("\n");
i += 1;
};
if (tail == 0) { return; };
let treg: str = "AX";
if (full == 1) { treg = "DX"; };
if (full == 2) { treg = "CX"; };
if (tail == 1 || tail == 2 || tail == 4) {
let top: str = "MOVB";
if (tail == 4) { top = "MOVL"; };
if (tail == 2) { top = "MOVW"; };
emitline("\t");
emitline(top);
emitline("\t");
emitline(treg);
emitline(", ");
emitdispreg((disp + full * 8): i64, basereg);
emitline("\n");
return;
};
if (dest_padded) {
emitline("\tMOVQ\t");
emitline(treg);
emitline(", ");
emitdispreg((disp + full * 8): i64, basereg);
emitline("\n");
return;
};
let pad: i32 = tagscradd(c, 8);
emitline("\tMOVQ\t");
emitline(treg);
emitline(", ");
emitdispreg(pad: i64, "BP");
emitline("\n");
emitline("\tLEAQ\t");
emitdispreg(pad: i64, "BP");
emitline(", SI\n");
emitline("\tLEAQ\t");
emitdispreg((disp + full * 8): i64, basereg);
emitline(", BX\n");
aggcopy(c, tail);
};
// copysrcnatsize — natural byte width of a whole-struct copy's SOURCE
// operand, read from the source node's stamped tinfo (tichase peels
// NAMED). #71: the four whole-struct field-copy sites must move this many
@@ -8399,34 +8481,7 @@ fn cgassign(c: *cgen, n: *syntax.node) void = {
emitline("\tPUSHQ\tBX\n");
cgexpr(c, n.rhs);
emitline("\tPOPQ\tBX\n");
let full: i32 = ssz / 8;
let i: i32 = 0;
for (i < full) {
let reg: str = "AX";
if (i == 1) { reg = "DX"; };
if (i == 2) { reg = "CX"; };
emitline("\tMOVQ\t");
emitline(reg);
emitline(", ");
emitdispreg((i * 8): i64, "BX");
emitline("\n");
i += 1;
};
if (tlm > 0) {
let top: str = "MOVB";
if (tlm == 4) { top = "MOVL"; };
if (tlm == 2) { top = "MOVW"; };
let treg: str = "AX";
if (full == 1) { treg = "DX"; };
if (full == 2) { treg = "CX"; };
emitline("\t");
emitline(top);
emitline("\t");
emitline(treg);
emitline(", ");
emitdispreg((full * 8): i64, "BX");
emitline("\n");
};
cgaggregstore(c, "BX", 0, ssz, false);
return;
};
};
@@ -9217,36 +9272,7 @@ fn cgassign(c: *cgen, n: *syntax.node) void = {
let scrc2: i32 = tagscradd(c, esz);
cgexpr(c, n.rhs); // call -> AX/DX/CX
// AX/DX/CX -> scratch (mirror cstage cgen.c:3434).
let full: i32 = esz / 8;
let tail: i32 = esz % 8;
let wi: i32 = 0;
for (wi < full) {
let rn: str = "AX";
if (wi == 1) { rn = "DX"; }
else { if (wi == 2) { rn = "CX"; }; };
emitline("\tMOVQ\t");
emitline(rn);
emitline(", ");
emitoff((scrc2 + wi * 8): i64);
emitline("(BP)\n");
wi += 1;
};
if (tail > 0) {
let top: str = "MOVQ";
if (tail == 1) { top = "MOVB"; }
else { if (tail == 2) { top = "MOVW"; }
else { if (tail == 4) { top = "MOVL"; }; }; };
let treg: str = "AX";
if (full == 1) { treg = "DX"; }
else { if (full == 2) { treg = "CX"; }; };
emitline("\t");
emitline(top);
emitline("\t");
emitline(treg);
emitline(", ");
emitoff((scrc2 + full * 8): i64);
emitline("(BP)\n");
};
cgaggregstore(c, "BP", scrc2, esz, true);
// dest &a[i] -> BX (#121 / #270-1b base resolve)
cgexpr(c, idx);
if (esz > 1) {
@@ -10601,34 +10627,7 @@ fn cgassign(c: *cgen, n: *syntax.node) void = {
emitline("\tMOVQ\t");
emitoff(lc.off: i64);
emitline("(BP), BX\n");
let full: i32 = ssz / 8;
let i: i32 = 0;
for (i < full) {
let reg: str = "AX";
if (i == 1) { reg = "DX"; };
if (i == 2) { reg = "CX"; };
emitline("\tMOVQ\t");
emitline(reg);
emitline(", ");
emitdispreg((fi.foff + i * 8): i64, "BX");
emitline("\n");
i += 1;
};
if (tlm > 0) {
let top: str = "MOVB";
if (tlm == 4) { top = "MOVL"; };
if (tlm == 2) { top = "MOVW"; };
let treg: str = "AX";
if (full == 1) { treg = "DX"; };
if (full == 2) { treg = "CX"; };
emitline("\t");
emitline(top);
emitline("\t");
emitline(treg);
emitline(", ");
emitdispreg((fi.foff + full * 8): i64, "BX");
emitline("\n");
};
cgaggregstore(c, "BX", fi.foff, ssz, false);
return;
};
};
@@ -10847,34 +10846,7 @@ fn cgassign(c: *cgen, n: *syntax.node) void = {
if (tlm == 0 || tlm == 1
|| tlm == 2 || tlm == 4) {
cgexpr(c, n.rhs);
let full: i32 = ssz / 8;
let i: i32 = 0;
for (i < full) {
let reg: str = "AX";
if (i == 1) { reg = "DX"; };
if (i == 2) { reg = "CX"; };
emitline("\tMOVQ\t");
emitline(reg);
emitline(", ");
emitoff((lc.off + fi.foff + i * 8): i64);
emitline("(BP)\n");
i += 1;
};
if (tlm > 0) {
let top: str = "MOVB";
if (tlm == 4) { top = "MOVL"; };
if (tlm == 2) { top = "MOVW"; };
let treg: str = "AX";
if (full == 1) { treg = "DX"; };
if (full == 2) { treg = "CX"; };
emitline("\t");
emitline(top);
emitline("\t");
emitline(treg);
emitline(", ");
emitoff((lc.off + fi.foff + full * 8): i64);
emitline("(BP)\n");
};
cgaggregstore(c, "BP", lc.off + fi.foff, ssz, false);
return;
};
};
@@ -11141,34 +11113,7 @@ fn cgassign(c: *cgen, n: *syntax.node) void = {
emitline("\tLEAQ\t");
emitsymname(c, bn);
emitline("(SB), BX\n");
let full: i32 = ssz / 8;
let i: i32 = 0;
for (i < full) {
let reg: str = "AX";
if (i == 1) { reg = "DX"; };
if (i == 2) { reg = "CX"; };
emitline("\tMOVQ\t");
emitline(reg);
emitline(", ");
emitdispreg((fi.foff + i * 8): i64, "BX");
emitline("\n");
i += 1;
};
if (tlm > 0) {
let top: str = "MOVB";
if (tlm == 4) { top = "MOVL"; };
if (tlm == 2) { top = "MOVW"; };
let treg: str = "AX";
if (full == 1) { treg = "DX"; };
if (full == 2) { treg = "CX"; };
emitline("\t");
emitline(top);
emitline("\t");
emitline(treg);
emitline(", ");
emitdispreg((fi.foff + full * 8): i64, "BX");
emitline("\n");
};
cgaggregstore(c, "BX", fi.foff, ssz, false);
return;
};
};
@@ -11848,52 +11793,7 @@ fn cgassign(c: *cgen, n: *syntax.node) void = {
emitline("(SB), BX\n");
};
};
let full: i32 = lsz / 8;
let i: i32 = 0;
for (i < full) {
let reg: str = "AX";
if (i == 1) { reg = "DX"; };
if (i == 2) { reg = "CX"; };
if (viacx) {
emitline("\tMOVQ\t");
emitline(reg);
emitline(", ");
emitdispreg((totaloff + i * 8): i64, "BX");
emitline("\n");
} else {
emitline("\tMOVQ\t");
emitline(reg);
emitline(", ");
emitoff((rootoff + totaloff + i * 8): i64);
emitline("(BP)\n");
};
i += 1;
};
if (tlm > 0) {
let top: str = "MOVB";
if (tlm == 4) { top = "MOVL"; };
if (tlm == 2) { top = "MOVW"; };
let treg: str = "AX";
if (full == 1) { treg = "DX"; };
if (full == 2) { treg = "CX"; };
if (viacx) {
emitline("\t");
emitline(top);
emitline("\t");
emitline(treg);
emitline(", ");
emitdispreg((totaloff + full * 8): i64, "BX");
emitline("\n");
} else {
emitline("\t");
emitline(top);
emitline("\t");
emitline(treg);
emitline(", ");
emitoff((rootoff + totaloff + full * 8): i64);
emitline("(BP)\n");
};
};
if (viacx) { cgaggregstore(c, "BX", totaloff, lsz, false); } else { cgaggregstore(c, "BP", rootoff + totaloff, lsz, false); };
return;
};
};
@@ -12638,34 +12538,7 @@ fn cgassign(c: *cgen, n: *syntax.node) void = {
if (tlm == 0 || tlm == 1
|| tlm == 2 || tlm == 4) {
cgexpr(c, n.rhs);
let full: i32 = lcsz / 8;
let i: i32 = 0;
for (i < full) {
let reg: str = "AX";
if (i == 1) { reg = "DX"; };
if (i == 2) { reg = "CX"; };
emitline("\tMOVQ\t");
emitline(reg);
emitline(", ");
emitoff((off + i * 8): i64);
emitline("(BP)\n");
i += 1;
};
if (tlm > 0) {
let top: str = "MOVB";
if (tlm == 4) { top = "MOVL"; };
if (tlm == 2) { top = "MOVW"; };
let treg: str = "AX";
if (full == 1) { treg = "DX"; };
if (full == 2) { treg = "CX"; };
emitline("\t");
emitline(top);
emitline("\t");
emitline(treg);
emitline(", ");
emitoff((off + full * 8): i64);
emitline("(BP)\n");
};
cgaggregstore(c, "BP", off, lcsz, false);
return;
};
};
@@ -12702,34 +12575,7 @@ fn cgassign(c: *cgen, n: *syntax.node) void = {
if (tlm == 0 || tlm == 1
|| tlm == 2 || tlm == 4) {
cgexpr(c, n.rhs);
let full: i32 = lcsz / 8;
let i: i32 = 0;
for (i < full) {
let reg: str = "AX";
if (i == 1) { reg = "DX"; };
if (i == 2) { reg = "CX"; };
emitline("\tMOVQ\t");
emitline(reg);
emitline(", ");
emitoff((off + i * 8): i64);
emitline("(BP)\n");
i += 1;
};
if (tlm > 0) {
let top: str = "MOVB";
if (tlm == 4) { top = "MOVL"; };
if (tlm == 2) { top = "MOVW"; };
let treg: str = "AX";
if (full == 1) { treg = "DX"; };
if (full == 2) { treg = "CX"; };
emitline("\t");
emitline(top);
emitline("\t");
emitline(treg);
emitline(", ");
emitoff((off + full * 8): i64);
emitline("(BP)\n");
};
cgaggregstore(c, "BP", off, lcsz, false);
return;
};
};