Hojun-Cho/ww
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

w6c+selfhost: cgen *T-rooted chained N_DOT (closes #22)

Browse Source 
Spine walker now accepts *T root at the last hop (cur->lhs->kind ==
N_IDENT, pu->kind == TY_PTR), substitutes pointee struct, emits
MOVQ off(BP), CX before offset arithmetic. Symmetric in N_DOT and
N_ASSIGN. Distinct gate from existing mid-chain *T-field branch
(cgen.c:4615) — no shadow.

Unblocks task #18 (bufio writer first-field embed). Pre-existing
*T-field mid-chain path unchanged.
This commit is contained in:
Hojun-Cho
2026-05-14 02:44:57 +09:00
parent d2f4659305
commit d66aef382a
6 changed files with 659 additions and 127 deletions
Download Patch File Download Diff File Expand all files Collapse all files

136
selfhost/cmd/wcc/cgenexpr.ww
View File

@@ -1615,15 +1615,27 @@ fn cgdot(c: *cgen, n: *node) void = {
let leaffi: *fieldinfo = nil;
let slicedelta: i32 = -1;
let isglobal: bool = false;
let ptrroot: bool = false;
let pok: bool = dotchainresolve(c, n,
&rootname, &rootoff, &totaloff,
&leaffi, &slicedelta, &isglobal);
&leaffi, &slicedelta, &isglobal, &ptrroot);
if (pok) {
// `*T` root: load the pointer slot once into CX,
// then index every leaf at total_off off CX. Same
// emit shape as the global path (LEAQ → CX) — only
// the loader instruction differs.
let viacx: bool = isglobal || ptrroot;
if (slicedelta >= 0) {
if (isglobal) {
emitline("\tLEAQ\t");
emitsymname(c, rootname);
emitline("(SB), CX\n");
if (viacx) {
if (ptrroot) {
emitline("\tMOVQ\t");
emitoff(rootoff: i64);
emitline("(BP), CX\n");
} else {
emitline("\tLEAQ\t");
emitsymname(c, rootname);
emitline("(SB), CX\n");
};
emitline("\tMOVQ\t");
emitdispreg((totaloff + slicedelta): i64, "CX");
emitline(", AX\n");
@@ -1635,10 +1647,16 @@ fn cgdot(c: *cgen, n: *node) void = {
return;
};
if (isstrtype(c, leaffi.tnode)) {
if (isglobal) {
emitline("\tLEAQ\t");
emitsymname(c, rootname);
emitline("(SB), CX\n");
if (viacx) {
if (ptrroot) {
emitline("\tMOVQ\t");
emitoff(rootoff: i64);
emitline("(BP), CX\n");
} else {
emitline("\tLEAQ\t");
emitsymname(c, rootname);
emitline("(SB), CX\n");
};
emitline("\tMOVQ\t");
emitdispreg(totaloff: i64, "CX");
emitline(", AX\n");
@@ -1658,10 +1676,16 @@ fn cgdot(c: *cgen, n: *node) void = {
if (isfloattype(c, leaffi.tnode)) {
let mov: str = "MOVSD";
if (isf32type(c, leaffi.tnode)) { mov = "MOVSS"; };
if (isglobal) {
emitline("\tLEAQ\t");
emitsymname(c, rootname);
emitline("(SB), CX\n");
if (viacx) {
if (ptrroot) {
emitline("\tMOVQ\t");
emitoff(rootoff: i64);
emitline("(BP), CX\n");
} else {
emitline("\tLEAQ\t");
emitsymname(c, rootname);
emitline("(SB), CX\n");
};
emitline("\t");
emitline(mov);
emitline("\t");
@@ -1677,10 +1701,16 @@ fn cgdot(c: *cgen, n: *node) void = {
return;
};
let lop: str = fieldloadop(c, leaffi);
if (isglobal) {
emitline("\tLEAQ\t");
emitsymname(c, rootname);
emitline("(SB), CX\n");
if (viacx) {
if (ptrroot) {
emitline("\tMOVQ\t");
emitoff(rootoff: i64);
emitline("(BP), CX\n");
} else {
emitline("\tLEAQ\t");
emitsymname(c, rootname);
emitline("(SB), CX\n");
};
emitline("\t");
emitline(lop);
emitline("\t");
@@ -1972,9 +2002,16 @@ fn cgun(c: *cgen, n: *node) void = {
let leaffi: *fieldinfo = nil;
let slicedelta: i32 = -1;
let isglobal: bool = false;
let ptrroot: bool = false;
let pok: bool = dotchainresolve(c, opnd,
&rootname, &rootoff, &totaloff,
&leaffi, &slicedelta, &isglobal);
&leaffi, &slicedelta, &isglobal,
&ptrroot);
// `&` through a `*T`-rooted chain is a
// separate shape (would need MOVQ + LEAQ
// disp(CX), AX). Not exercised by current
// callers — skip and fall through.
if (ptrroot) { pok = false; };
if (pok) {
let extra: i32 = 0;
if (slicedelta >= 0) { extra = slicedelta; };
@@ -3924,16 +3961,27 @@ fn cgassign(c: *cgen, n: *node) void = {
let leaffi: *fieldinfo = nil;
let slicedelta: i32 = -1;
let isglobal: bool = false;
let ptrroot: bool = false;
let yok: bool = dotchainresolve(c, lhs,
&rootname, &rootoff, &totaloff,
&leaffi, &slicedelta, &isglobal);
&leaffi, &slicedelta, &isglobal, &ptrroot);
if (yok) {
// `*T` root and global share the CX-based emit:
// loader runs AFTER cgexpr(rhs) so AX/BX/X0 stay
// intact, then stores at total_off off CX.
let viacx: bool = isglobal || ptrroot;
if (slicedelta >= 0) {
cgexpr(c, n.rhs);
if (isglobal) {
emitline("\tLEAQ\t");
emitsymname(c, rootname);
emitline("(SB), CX\n");
if (viacx) {
if (ptrroot) {
emitline("\tMOVQ\t");
emitoff(rootoff: i64);
emitline("(BP), CX\n");
} else {
emitline("\tLEAQ\t");
emitsymname(c, rootname);
emitline("(SB), CX\n");
};
emitline("\tMOVQ\tAX, ");
emitdispreg((totaloff + slicedelta): i64, "CX");
emitline("\n");
@@ -3946,10 +3994,16 @@ fn cgassign(c: *cgen, n: *node) void = {
};
if (isstrtype(c, leaffi.tnode)) {
cgexpr(c, n.rhs);
if (isglobal) {
emitline("\tLEAQ\t");
emitsymname(c, rootname);
emitline("(SB), CX\n");
if (viacx) {
if (ptrroot) {
emitline("\tMOVQ\t");
emitoff(rootoff: i64);
emitline("(BP), CX\n");
} else {
emitline("\tLEAQ\t");
emitsymname(c, rootname);
emitline("(SB), CX\n");
};
emitline("\tMOVQ\tAX, ");
emitdispreg(totaloff: i64, "CX");
emitline("\n");
@@ -3970,10 +4024,16 @@ fn cgassign(c: *cgen, n: *node) void = {
let mov: str = "MOVSD";
if (isf32type(c, leaffi.tnode)) { mov = "MOVSS"; };
cgexpr(c, n.rhs);
if (isglobal) {
emitline("\tLEAQ\t");
emitsymname(c, rootname);
emitline("(SB), CX\n");
if (viacx) {
if (ptrroot) {
emitline("\tMOVQ\t");
emitoff(rootoff: i64);
emitline("(BP), CX\n");
} else {
emitline("\tLEAQ\t");
emitsymname(c, rootname);
emitline("(SB), CX\n");
};
emitline("\t");
emitline(mov);
emitline("\tX0, ");
@@ -3990,10 +4050,16 @@ fn cgassign(c: *cgen, n: *node) void = {
};
let sop: str = fieldstoreop(c, leaffi);
cgexpr(c, n.rhs);
if (isglobal) {
emitline("\tLEAQ\t");
emitsymname(c, rootname);
emitline("(SB), CX\n");
if (viacx) {
if (ptrroot) {
emitline("\tMOVQ\t");
emitoff(rootoff: i64);
emitline("(BP), CX\n");
} else {
emitline("\tLEAQ\t");
emitsymname(c, rootname);
emitline("(SB), CX\n");
};
emitline("\t");
emitline(sop);
emitline("\tAX, ");