From dd24de11342f597a4fd6435a260600c2938db089 Mon Sep 17 00:00:00 2001 From: Hojun-Cho Date: Sat, 13 Jun 2026 15:03:07 +0900 Subject: [PATCH] wcc: whole-struct field-copy completes the ragged tail greedily, both stages MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit A `x.f = o` copy of a whole struct field emits a MOVQ run for the 8-byte chunks plus a tail. Both stages inlined a tail that handled only {4,1}: a 4-byte remainder went MOVL, a 1-byte MOVB, but {2,3,5,6,7} fell through to an 8-byte MOVQ that OVER-READS the source and OVER-WRITES the field's natural-offset successor. With #44 packing a successor at its natural offset, that is a live clobber: outer2{i:inner2{u8,u8}, mark:i32} copies i with `MOVQ -8(BP),AX; MOVQ AX,-16(BP)` and wipes mark@-12; the correct move is a single MOVW. Same defect in cstage (cgen.c) and the four wwstage field-copy sites (cgenexpr.ww: via-ptr, direct-BP-local, global, and the multi-hop dot-chain CX variant). Fix: replace each inline {4,1} tail with the descending greedy 4/2/1 (MOVL/MOVW/MOVB) the canonical aggregate-copy emitters already use, so the tail is complete on every natural size. This is path (alpha) of the #73 brief — a corpus-neutral, no-workaround completion of the inline tail. Routing field copies through the shared aggcopy/cg_aggcopy choke- point (beta) is the balloon: those emitters hardcode (SI)->(BX) at offset k with zero base displacement, but the four field-copy dsts are heterogeneous (foff(BX), boff+foff(BP) with no base reg, totaloff(CX)), so routing forces per-site-per-stage LEAQ src->SI + LEAQ dst->BX rewrites with no mechanical cross-stage mirror at the CX site = a gate-blind cs!=ww risk. The emitter extraction is filed as a later addressing- unification arc (#12). The ragged tail is corpus-absent (every corpus field copy is tail in {0,4}, where greedy 4/2/1 emits exactly what the old {4,1} tail did), so this is CLASS-N: zero corpus move on both stages, byte-id holds by construction. The cstage <=24 N_CALL receive site (cgen.c:5234) is a different copy family (sret result read from AX/DX/CX, not a mem-to-mem field copy) and already handles 4/2/1; left untouched. The str/slice/tagged/tuple 4/1 sites (#76) are likewise a separate family, filed not folded. 989_structcopytail_run pins it on both driver twins: tail2 (MOVW), tail6 (MOVL+MOVW), tail7 (the full MOVL+MOVW+MOVB ladder, the MOVB-path row), plus an 8-aligned ctl8 (tail-0 control). Pre-fix cstage clobbers mark and exits non-zero -> cs!=ww; post-fix 4/4 ok cs==ww. --- Makefile | 17 ++ cmd/w6c/cgen.c | 28 +++- selfhost/cmd/w6c/main.combined.ww | 148 +++++++++++------ selfhost/cmd/wcc/cgenexpr.ww | 148 +++++++++++------ selfhost/cmd/wwdump/main.combined.ww | 148 +++++++++++------ test/wcc/989_structcopytail_run.c | 235 +++++++++++++++++++++++++++ 6 files changed, 576 insertions(+), 148 deletions(-) create mode 100644 test/wcc/989_structcopytail_run.c diff --git a/Makefile b/Makefile index f944e386..8e47db25 100644 --- a/Makefile +++ b/Makefile @@ -258,6 +258,7 @@ TESTS = $(BIN)/test_smoke $(BIN)/test_lex $(BIN)/test_parse $(BIN)/test_check \ $(BIN)/test_tagtupfieldsize_run \ $(BIN)/test_nestfield_run \ $(BIN)/test_structlocal_frame \ + $(BIN)/test_structcopytail_run \ $(BIN)/test_arrlit_tail_zero_run \ $(BIN)/test_defdim_slice_run \ $(BIN)/test_trystr_run \ @@ -789,6 +790,22 @@ $(BIN)/test_structlocal_frame: test/wcc/989_structlocal_frame.c \ $(BIN)/w6c $(BIN)/w6c_ww | $(BIN) $(CC) $(CFLAGS) -o $@ $< +# 989_structcopytail_run (#73): a whole-struct field-copy `x.i = o` whose +# source natural size %8 lands in {2,3,5,6,7} must move exactly that many +# bytes via a descending greedy 8->4->2->1 tail (MOVL/MOVW/MOVB), not round +# the ragged remainder up to an 8-byte MOVQ that over-writes the field's +# natural-offset successor. BOTH stages inlined a tail handling only {4,1}; +# tail-2 (inner2{u8,u8} in outer2{i,mark:i32}) and tail-6 (inner6{u16,u16, +# u16} in outer6{i,mark:u8}) over-wrote MARK with an 8B MOVQ. Builds+runs on +# BOTH driver twins (rule-10), pinning the absolute 0; ctl8 (8-aligned, zero +# tail) pins the unchanged path. +$(BIN)/test_structcopytail_run: test/wcc/989_structcopytail_run.c \ + $(BIN)/ww $(BIN)/ww_ww \ + $(BIN)/w6c $(BIN)/w6a $(BIN)/w6l \ + $(BIN)/w6c_ww $(BIN)/w6a_ww $(BIN)/w6l_ww \ + $(LIB)/libwwrt.a | $(BIN) + $(CC) $(CFLAGS) -o $@ $< + # 989_arrlit_tail_zero_run (#13): an under-length array literal zero-fills the # unspecified tail, not the last value. Builds+runs on BOTH driver twins # (rule-10), pinning the absolute value (pre-fix ww tail = last value). diff --git a/cmd/w6c/cgen.c b/cmd/w6c/cgen.c index 9275403f..7338dba8 100644 --- a/cmd/w6c/cgen.c +++ b/cmd/w6c/cgen.c @@ -5313,15 +5313,29 @@ cgexpr(Cg *c, Node *n, Local *locals) ins2(c, A_MOVQ, areg(D_AX), amem(D_BP, boff + foff + k)); k += 8; } - if (k < ssz) { - int tail = ssz - k; - int lop = (tail == 4) ? A_MOVL - : (tail == 1 ? A_MOVB : A_MOVQ); - ins2(c, lop, amem(D_BP, soff + k), areg(D_AX)); + if (k + 4 <= ssz) { + ins2(c, A_MOVL, amem(D_BP, soff + k), areg(D_AX)); if (via_ptr || is_global) - ins2(c, lop, areg(D_AX), amem(D_BX, foff + k)); + ins2(c, A_MOVL, areg(D_AX), amem(D_BX, foff + k)); else - ins2(c, lop, areg(D_AX), amem(D_BP, boff + foff + k)); + ins2(c, A_MOVL, areg(D_AX), amem(D_BP, boff + foff + k)); + k += 4; + } + if (k + 2 <= ssz) { + ins2(c, A_MOVW, amem(D_BP, soff + k), areg(D_AX)); + if (via_ptr || is_global) + ins2(c, A_MOVW, areg(D_AX), amem(D_BX, foff + k)); + else + ins2(c, A_MOVW, areg(D_AX), amem(D_BP, boff + foff + k)); + k += 2; + } + if (k + 1 <= ssz) { + ins2(c, A_MOVB, amem(D_BP, soff + k), areg(D_AX)); + if (via_ptr || is_global) + ins2(c, A_MOVB, areg(D_AX), amem(D_BX, foff + k)); + else + ins2(c, A_MOVB, areg(D_AX), amem(D_BP, boff + foff + k)); + k += 1; } break; } diff --git a/selfhost/cmd/w6c/main.combined.ww b/selfhost/cmd/w6c/main.combined.ww index 048c7299..73c12b78 100644 --- a/selfhost/cmd/w6c/main.combined.ww +++ b/selfhost/cmd/w6c/main.combined.ww @@ -33325,21 +33325,32 @@ fn cgassign(c: *cgen, n: *node) void = { emitline("\n"); k += 8; }; - if (k < ssz) { - let tail: i32 = ssz - k; - let lop: str = "MOVQ"; - if (tail == 4) { lop = "MOVL"; } - else { if (tail == 1) { lop = "MOVB"; }; }; - emitline("\t"); - emitline(lop); - emitline("\t"); + if (k + 4 <= ssz) { + emitline("\tMOVL\t"); emitoff((srhs.off + k): i64); emitline("(BP), AX\n"); - emitline("\t"); - emitline(lop); - emitline("\tAX, "); + emitline("\tMOVL\tAX, "); emitdispreg((fi.foff + k): i64, "BX"); emitline("\n"); + k += 4; + }; + if (k + 2 <= ssz) { + emitline("\tMOVW\t"); + emitoff((srhs.off + k): i64); + emitline("(BP), AX\n"); + emitline("\tMOVW\tAX, "); + emitdispreg((fi.foff + k): i64, "BX"); + emitline("\n"); + k += 2; + }; + if (k + 1 <= ssz) { + emitline("\tMOVB\t"); + emitoff((srhs.off + k): i64); + emitline("(BP), AX\n"); + emitline("\tMOVB\tAX, "); + emitdispreg((fi.foff + k): i64, "BX"); + emitline("\n"); + k += 1; }; return; };}; @@ -33551,21 +33562,32 @@ fn cgassign(c: *cgen, n: *node) void = { emitline("(BP)\n"); k += 8; }; - if (k < ssz) { - let tail: i32 = ssz - k; - let lop: str = "MOVQ"; - if (tail == 4) { lop = "MOVL"; } - else { if (tail == 1) { lop = "MOVB"; }; }; - emitline("\t"); - emitline(lop); - emitline("\t"); + if (k + 4 <= ssz) { + emitline("\tMOVL\t"); emitoff((srhs.off + k): i64); emitline("(BP), AX\n"); - emitline("\t"); - emitline(lop); - emitline("\tAX, "); + emitline("\tMOVL\tAX, "); emitoff((lc.off + fi.foff + k): i64); emitline("(BP)\n"); + k += 4; + }; + if (k + 2 <= ssz) { + emitline("\tMOVW\t"); + emitoff((srhs.off + k): i64); + emitline("(BP), AX\n"); + emitline("\tMOVW\tAX, "); + emitoff((lc.off + fi.foff + k): i64); + emitline("(BP)\n"); + k += 2; + }; + if (k + 1 <= ssz) { + emitline("\tMOVB\t"); + emitoff((srhs.off + k): i64); + emitline("(BP), AX\n"); + emitline("\tMOVB\tAX, "); + emitoff((lc.off + fi.foff + k): i64); + emitline("(BP)\n"); + k += 1; }; return; };}; @@ -33838,21 +33860,32 @@ fn cgassign(c: *cgen, n: *node) void = { emitline("\n"); k += 8; }; - if (k < ssz) { - let tail: i32 = ssz - k; - let lop: str = "MOVQ"; - if (tail == 4) { lop = "MOVL"; } - else { if (tail == 1) { lop = "MOVB"; }; }; - emitline("\t"); - emitline(lop); - emitline("\t"); + if (k + 4 <= ssz) { + emitline("\tMOVL\t"); emitoff((srhs.off + k): i64); emitline("(BP), AX\n"); - emitline("\t"); - emitline(lop); - emitline("\tAX, "); + emitline("\tMOVL\tAX, "); emitdispreg((fi.foff + k): i64, "BX"); emitline("\n"); + k += 4; + }; + if (k + 2 <= ssz) { + emitline("\tMOVW\t"); + emitoff((srhs.off + k): i64); + emitline("(BP), AX\n"); + emitline("\tMOVW\tAX, "); + emitdispreg((fi.foff + k): i64, "BX"); + emitline("\n"); + k += 2; + }; + if (k + 1 <= ssz) { + emitline("\tMOVB\t"); + emitoff((srhs.off + k): i64); + emitline("(BP), AX\n"); + emitline("\tMOVB\tAX, "); + emitdispreg((fi.foff + k): i64, "BX"); + emitline("\n"); + k += 1; }; return; };}; @@ -34487,29 +34520,50 @@ fn cgassign(c: *cgen, n: *node) void = { }; k += 8; }; - if (k < ssz) { - let tail: i32 = ssz - k; - let lop: str = "MOVQ"; - if (tail == 4) { lop = "MOVL"; } - else { if (tail == 1) { lop = "MOVB"; }; }; - emitline("\t"); - emitline(lop); - emitline("\t"); + if (k + 4 <= ssz) { + emitline("\tMOVL\t"); emitoff((srhs.off + k): i64); emitline("(BP), AX\n"); if (viacx) { - emitline("\t"); - emitline(lop); - emitline("\tAX, "); + emitline("\tMOVL\tAX, "); emitdispreg((totaloff + k): i64, "CX"); emitline("\n"); } else { - emitline("\t"); - emitline(lop); - emitline("\tAX, "); + emitline("\tMOVL\tAX, "); emitoff((rootoff + totaloff + k): i64); emitline("(BP)\n"); }; + k += 4; + }; + if (k + 2 <= ssz) { + emitline("\tMOVW\t"); + emitoff((srhs.off + k): i64); + emitline("(BP), AX\n"); + if (viacx) { + emitline("\tMOVW\tAX, "); + emitdispreg((totaloff + k): i64, "CX"); + emitline("\n"); + } else { + emitline("\tMOVW\tAX, "); + emitoff((rootoff + totaloff + k): i64); + emitline("(BP)\n"); + }; + k += 2; + }; + if (k + 1 <= ssz) { + emitline("\tMOVB\t"); + emitoff((srhs.off + k): i64); + emitline("(BP), AX\n"); + if (viacx) { + emitline("\tMOVB\tAX, "); + emitdispreg((totaloff + k): i64, "CX"); + emitline("\n"); + } else { + emitline("\tMOVB\tAX, "); + emitoff((rootoff + totaloff + k): i64); + emitline("(BP)\n"); + }; + k += 1; }; return; };}; diff --git a/selfhost/cmd/wcc/cgenexpr.ww b/selfhost/cmd/wcc/cgenexpr.ww index 32eff84b..b52cddba 100644 --- a/selfhost/cmd/wcc/cgenexpr.ww +++ b/selfhost/cmd/wcc/cgenexpr.ww @@ -9979,21 +9979,32 @@ fn cgassign(c: *cgen, n: *node) void = { emitline("\n"); k += 8; }; - if (k < ssz) { - let tail: i32 = ssz - k; - let lop: str = "MOVQ"; - if (tail == 4) { lop = "MOVL"; } - else { if (tail == 1) { lop = "MOVB"; }; }; - emitline("\t"); - emitline(lop); - emitline("\t"); + if (k + 4 <= ssz) { + emitline("\tMOVL\t"); emitoff((srhs.off + k): i64); emitline("(BP), AX\n"); - emitline("\t"); - emitline(lop); - emitline("\tAX, "); + emitline("\tMOVL\tAX, "); emitdispreg((fi.foff + k): i64, "BX"); emitline("\n"); + k += 4; + }; + if (k + 2 <= ssz) { + emitline("\tMOVW\t"); + emitoff((srhs.off + k): i64); + emitline("(BP), AX\n"); + emitline("\tMOVW\tAX, "); + emitdispreg((fi.foff + k): i64, "BX"); + emitline("\n"); + k += 2; + }; + if (k + 1 <= ssz) { + emitline("\tMOVB\t"); + emitoff((srhs.off + k): i64); + emitline("(BP), AX\n"); + emitline("\tMOVB\tAX, "); + emitdispreg((fi.foff + k): i64, "BX"); + emitline("\n"); + k += 1; }; return; };}; @@ -10205,21 +10216,32 @@ fn cgassign(c: *cgen, n: *node) void = { emitline("(BP)\n"); k += 8; }; - if (k < ssz) { - let tail: i32 = ssz - k; - let lop: str = "MOVQ"; - if (tail == 4) { lop = "MOVL"; } - else { if (tail == 1) { lop = "MOVB"; }; }; - emitline("\t"); - emitline(lop); - emitline("\t"); + if (k + 4 <= ssz) { + emitline("\tMOVL\t"); emitoff((srhs.off + k): i64); emitline("(BP), AX\n"); - emitline("\t"); - emitline(lop); - emitline("\tAX, "); + emitline("\tMOVL\tAX, "); emitoff((lc.off + fi.foff + k): i64); emitline("(BP)\n"); + k += 4; + }; + if (k + 2 <= ssz) { + emitline("\tMOVW\t"); + emitoff((srhs.off + k): i64); + emitline("(BP), AX\n"); + emitline("\tMOVW\tAX, "); + emitoff((lc.off + fi.foff + k): i64); + emitline("(BP)\n"); + k += 2; + }; + if (k + 1 <= ssz) { + emitline("\tMOVB\t"); + emitoff((srhs.off + k): i64); + emitline("(BP), AX\n"); + emitline("\tMOVB\tAX, "); + emitoff((lc.off + fi.foff + k): i64); + emitline("(BP)\n"); + k += 1; }; return; };}; @@ -10492,21 +10514,32 @@ fn cgassign(c: *cgen, n: *node) void = { emitline("\n"); k += 8; }; - if (k < ssz) { - let tail: i32 = ssz - k; - let lop: str = "MOVQ"; - if (tail == 4) { lop = "MOVL"; } - else { if (tail == 1) { lop = "MOVB"; }; }; - emitline("\t"); - emitline(lop); - emitline("\t"); + if (k + 4 <= ssz) { + emitline("\tMOVL\t"); emitoff((srhs.off + k): i64); emitline("(BP), AX\n"); - emitline("\t"); - emitline(lop); - emitline("\tAX, "); + emitline("\tMOVL\tAX, "); emitdispreg((fi.foff + k): i64, "BX"); emitline("\n"); + k += 4; + }; + if (k + 2 <= ssz) { + emitline("\tMOVW\t"); + emitoff((srhs.off + k): i64); + emitline("(BP), AX\n"); + emitline("\tMOVW\tAX, "); + emitdispreg((fi.foff + k): i64, "BX"); + emitline("\n"); + k += 2; + }; + if (k + 1 <= ssz) { + emitline("\tMOVB\t"); + emitoff((srhs.off + k): i64); + emitline("(BP), AX\n"); + emitline("\tMOVB\tAX, "); + emitdispreg((fi.foff + k): i64, "BX"); + emitline("\n"); + k += 1; }; return; };}; @@ -11141,29 +11174,50 @@ fn cgassign(c: *cgen, n: *node) void = { }; k += 8; }; - if (k < ssz) { - let tail: i32 = ssz - k; - let lop: str = "MOVQ"; - if (tail == 4) { lop = "MOVL"; } - else { if (tail == 1) { lop = "MOVB"; }; }; - emitline("\t"); - emitline(lop); - emitline("\t"); + if (k + 4 <= ssz) { + emitline("\tMOVL\t"); emitoff((srhs.off + k): i64); emitline("(BP), AX\n"); if (viacx) { - emitline("\t"); - emitline(lop); - emitline("\tAX, "); + emitline("\tMOVL\tAX, "); emitdispreg((totaloff + k): i64, "CX"); emitline("\n"); } else { - emitline("\t"); - emitline(lop); - emitline("\tAX, "); + emitline("\tMOVL\tAX, "); emitoff((rootoff + totaloff + k): i64); emitline("(BP)\n"); }; + k += 4; + }; + if (k + 2 <= ssz) { + emitline("\tMOVW\t"); + emitoff((srhs.off + k): i64); + emitline("(BP), AX\n"); + if (viacx) { + emitline("\tMOVW\tAX, "); + emitdispreg((totaloff + k): i64, "CX"); + emitline("\n"); + } else { + emitline("\tMOVW\tAX, "); + emitoff((rootoff + totaloff + k): i64); + emitline("(BP)\n"); + }; + k += 2; + }; + if (k + 1 <= ssz) { + emitline("\tMOVB\t"); + emitoff((srhs.off + k): i64); + emitline("(BP), AX\n"); + if (viacx) { + emitline("\tMOVB\tAX, "); + emitdispreg((totaloff + k): i64, "CX"); + emitline("\n"); + } else { + emitline("\tMOVB\tAX, "); + emitoff((rootoff + totaloff + k): i64); + emitline("(BP)\n"); + }; + k += 1; }; return; };}; diff --git a/selfhost/cmd/wwdump/main.combined.ww b/selfhost/cmd/wwdump/main.combined.ww index fcab0b05..d44e2ed7 100644 --- a/selfhost/cmd/wwdump/main.combined.ww +++ b/selfhost/cmd/wwdump/main.combined.ww @@ -33325,21 +33325,32 @@ fn cgassign(c: *cgen, n: *node) void = { emitline("\n"); k += 8; }; - if (k < ssz) { - let tail: i32 = ssz - k; - let lop: str = "MOVQ"; - if (tail == 4) { lop = "MOVL"; } - else { if (tail == 1) { lop = "MOVB"; }; }; - emitline("\t"); - emitline(lop); - emitline("\t"); + if (k + 4 <= ssz) { + emitline("\tMOVL\t"); emitoff((srhs.off + k): i64); emitline("(BP), AX\n"); - emitline("\t"); - emitline(lop); - emitline("\tAX, "); + emitline("\tMOVL\tAX, "); emitdispreg((fi.foff + k): i64, "BX"); emitline("\n"); + k += 4; + }; + if (k + 2 <= ssz) { + emitline("\tMOVW\t"); + emitoff((srhs.off + k): i64); + emitline("(BP), AX\n"); + emitline("\tMOVW\tAX, "); + emitdispreg((fi.foff + k): i64, "BX"); + emitline("\n"); + k += 2; + }; + if (k + 1 <= ssz) { + emitline("\tMOVB\t"); + emitoff((srhs.off + k): i64); + emitline("(BP), AX\n"); + emitline("\tMOVB\tAX, "); + emitdispreg((fi.foff + k): i64, "BX"); + emitline("\n"); + k += 1; }; return; };}; @@ -33551,21 +33562,32 @@ fn cgassign(c: *cgen, n: *node) void = { emitline("(BP)\n"); k += 8; }; - if (k < ssz) { - let tail: i32 = ssz - k; - let lop: str = "MOVQ"; - if (tail == 4) { lop = "MOVL"; } - else { if (tail == 1) { lop = "MOVB"; }; }; - emitline("\t"); - emitline(lop); - emitline("\t"); + if (k + 4 <= ssz) { + emitline("\tMOVL\t"); emitoff((srhs.off + k): i64); emitline("(BP), AX\n"); - emitline("\t"); - emitline(lop); - emitline("\tAX, "); + emitline("\tMOVL\tAX, "); emitoff((lc.off + fi.foff + k): i64); emitline("(BP)\n"); + k += 4; + }; + if (k + 2 <= ssz) { + emitline("\tMOVW\t"); + emitoff((srhs.off + k): i64); + emitline("(BP), AX\n"); + emitline("\tMOVW\tAX, "); + emitoff((lc.off + fi.foff + k): i64); + emitline("(BP)\n"); + k += 2; + }; + if (k + 1 <= ssz) { + emitline("\tMOVB\t"); + emitoff((srhs.off + k): i64); + emitline("(BP), AX\n"); + emitline("\tMOVB\tAX, "); + emitoff((lc.off + fi.foff + k): i64); + emitline("(BP)\n"); + k += 1; }; return; };}; @@ -33838,21 +33860,32 @@ fn cgassign(c: *cgen, n: *node) void = { emitline("\n"); k += 8; }; - if (k < ssz) { - let tail: i32 = ssz - k; - let lop: str = "MOVQ"; - if (tail == 4) { lop = "MOVL"; } - else { if (tail == 1) { lop = "MOVB"; }; }; - emitline("\t"); - emitline(lop); - emitline("\t"); + if (k + 4 <= ssz) { + emitline("\tMOVL\t"); emitoff((srhs.off + k): i64); emitline("(BP), AX\n"); - emitline("\t"); - emitline(lop); - emitline("\tAX, "); + emitline("\tMOVL\tAX, "); emitdispreg((fi.foff + k): i64, "BX"); emitline("\n"); + k += 4; + }; + if (k + 2 <= ssz) { + emitline("\tMOVW\t"); + emitoff((srhs.off + k): i64); + emitline("(BP), AX\n"); + emitline("\tMOVW\tAX, "); + emitdispreg((fi.foff + k): i64, "BX"); + emitline("\n"); + k += 2; + }; + if (k + 1 <= ssz) { + emitline("\tMOVB\t"); + emitoff((srhs.off + k): i64); + emitline("(BP), AX\n"); + emitline("\tMOVB\tAX, "); + emitdispreg((fi.foff + k): i64, "BX"); + emitline("\n"); + k += 1; }; return; };}; @@ -34487,29 +34520,50 @@ fn cgassign(c: *cgen, n: *node) void = { }; k += 8; }; - if (k < ssz) { - let tail: i32 = ssz - k; - let lop: str = "MOVQ"; - if (tail == 4) { lop = "MOVL"; } - else { if (tail == 1) { lop = "MOVB"; }; }; - emitline("\t"); - emitline(lop); - emitline("\t"); + if (k + 4 <= ssz) { + emitline("\tMOVL\t"); emitoff((srhs.off + k): i64); emitline("(BP), AX\n"); if (viacx) { - emitline("\t"); - emitline(lop); - emitline("\tAX, "); + emitline("\tMOVL\tAX, "); emitdispreg((totaloff + k): i64, "CX"); emitline("\n"); } else { - emitline("\t"); - emitline(lop); - emitline("\tAX, "); + emitline("\tMOVL\tAX, "); emitoff((rootoff + totaloff + k): i64); emitline("(BP)\n"); }; + k += 4; + }; + if (k + 2 <= ssz) { + emitline("\tMOVW\t"); + emitoff((srhs.off + k): i64); + emitline("(BP), AX\n"); + if (viacx) { + emitline("\tMOVW\tAX, "); + emitdispreg((totaloff + k): i64, "CX"); + emitline("\n"); + } else { + emitline("\tMOVW\tAX, "); + emitoff((rootoff + totaloff + k): i64); + emitline("(BP)\n"); + }; + k += 2; + }; + if (k + 1 <= ssz) { + emitline("\tMOVB\t"); + emitoff((srhs.off + k): i64); + emitline("(BP), AX\n"); + if (viacx) { + emitline("\tMOVB\tAX, "); + emitdispreg((totaloff + k): i64, "CX"); + emitline("\n"); + } else { + emitline("\tMOVB\tAX, "); + emitoff((rootoff + totaloff + k): i64); + emitline("(BP)\n"); + }; + k += 1; }; return; };}; diff --git a/test/wcc/989_structcopytail_run.c b/test/wcc/989_structcopytail_run.c new file mode 100644 index 00000000..fc07cb32 --- /dev/null +++ b/test/wcc/989_structcopytail_run.c @@ -0,0 +1,235 @@ +/* + * 989_structcopytail_run — #73 teeth (recorded by impl-55, 2026-06-13). + * + * Whole-struct field-copy ragged tail. A `x.i = o` copy of a struct whose + * NATURAL size is not 8-aligned must move exactly that many bytes via a + * descending-greedy 8->4->2->1 tail (MOVL/MOVW/MOVB), NOT round up to an + * 8-byte MOVQ that bleeds into the field's natural-offset successor. + * + * THIS TEST IS cs!=ww-RED UNTIL #73. As impl-55 proved (2026-06-13), BOTH + * stages inline a tail handling only {4,1}; a natural size %8 in + * {2,3,5,6,7} falls through to an 8-byte MOVQ over-write: + * - wwstage: cgenexpr.ww 4 field-copy sites (now length-correct via #71, + * tail still 4/1). + * - cstage: cmd/w6c/cgen.c:5302/5318 (+ siblings 2970/3332/5268/6255/ + * 6314/7259) — str_fu->size length is already natural, tail is 4/1. + * ASM PROOF (tail2, x.i = o): cstage emits `MOVQ -8(BP),AX; MOVQ AX,-16(BP)` + * (8B over-write -> clobbers mark@-12). #73 routes both stages' field copy + * through the canonical greedy emitter (cstage cg_aggcopy@2241 / ww + * aggcopy@1662), completing the tail on both -> this test goes green + * cs==ww. Do NOT wire it before #73 lands. + * + * Shapes: + * tail2: inner2{a:u8,b:u8} (size 2) in outer2{i:inner2, mark:i32}; #44 + * packs mark at natural offset 4. A MOVQ copy of i writes [0,8) + * and clobbers mark@4; the MOVW tail writes [0,2). + * tail6: inner6{a:u16,b:u16,c:u16} (size 6) in outer6{i:inner6, mark:u8}; + * mark at natural offset 6. A MOVQ copy writes [0,8) and clobbers + * mark@6; the MOVL+MOVW tail writes [0,6). + * ctl8: inner8{a:i64} (size 8, 8-aligned) — the MOVQ loop alone, no + * tail; proves the 8-aligned path is unchanged. + * Each program reads every field back and returns the 1-based index of the + * first mismatch, 0 on all-correct. Both stages build+run (rule-10), pin 0. + */ +#include +#include +#include +#include +#include +#include + +static int +runwait(const char *cmd) +{ + int rc = system(cmd); + if (rc == -1) return -1; + if (WIFEXITED(rc)) return WEXITSTATUS(rc); + return -1; +} + +struct row { + const char *label; + const char *src; + int want_exit; /* >= 0: pin the absolute value; -1: cs==ww only */ +}; + +static const struct row rows[] = { + /* tail2 — whole-copy of a 2-byte struct; mark (nat offset 4) must + * survive. Pre-tail-fix MOVQ writes [0,8) -> mark clobbered. */ + { "tail2", + "package main;\n" + "type inner2 = struct { a: u8, b: u8 };\n" + "type outer2 = struct { i: inner2, mark: i32 };\n" + "export fn main() int = {\n" + " let o: inner2 = inner2 { a = 0x11, b = 0x22 };\n" + " let x: outer2;\n" + " x.mark = 0x7f7f7f7f;\n" + " x.i = o;\n" + " if (x.i.a: int != 0x11) { return 1; };\n" + " if (x.i.b: int != 0x22) { return 2; };\n" + " if (x.mark != 0x7f7f7f7f) { return 3; };\n" + " return 0;\n" + "};\n", + 0 }, + + /* tail6 — whole-copy of a 6-byte struct; mark:u8 (nat offset 6) must + * survive. Pre-tail-fix MOVQ writes [0,8) -> mark clobbered; the + * MOVL+MOVW tail writes exactly [0,6). */ + { "tail6", + "package main;\n" + "type inner6 = struct { a: u16, b: u16, c: u16 };\n" + "type outer6 = struct { i: inner6, mark: u8 };\n" + "export fn main() int = {\n" + " let o: inner6 = inner6 { a = 0x1111, b = 0x2222, c = 0x3333 };\n" + " let x: outer6;\n" + " x.mark = 0x5a;\n" + " x.i = o;\n" + " if (x.i.a: int != 0x1111) { return 1; };\n" + " if (x.i.b: int != 0x2222) { return 2; };\n" + " if (x.i.c: int != 0x3333) { return 3; };\n" + " if (x.mark: int != 0x5a) { return 4; };\n" + " return 0;\n" + "};\n", + 0 }, + + /* tail7 — whole-copy of a 7-byte struct (seven u8, align 1); mark:u8 + * at natural offset 7 must survive. Exercises the FULL descending tail + * ladder in one shape: MOVL[0,4) + MOVW[4,6) + MOVB[6,7). Pre-fix the + * 4/1-only tail defaulted size-7 to a single 8-byte MOVQ writing [0,8) + * -> clobbers mark@7; this is the only row hitting the MOVB tail. */ + { "tail7", + "package main;\n" + "type inner7 = struct { a: u8, b: u8, c: u8, d: u8, e: u8, f: u8, g: u8 };\n" + "type outer7 = struct { i: inner7, mark: u8 };\n" + "export fn main() int = {\n" + " let o: inner7 = inner7 { a = 0x11, b = 0x22, c = 0x33, d = 0x44, e = 0x55, f = 0x66, g = 0x77 };\n" + " let x: outer7;\n" + " x.mark = 0x5a;\n" + " x.i = o;\n" + " if (x.i.a: int != 0x11) { return 1; };\n" + " if (x.i.b: int != 0x22) { return 2; };\n" + " if (x.i.c: int != 0x33) { return 3; };\n" + " if (x.i.d: int != 0x44) { return 4; };\n" + " if (x.i.e: int != 0x55) { return 5; };\n" + " if (x.i.f: int != 0x66) { return 6; };\n" + " if (x.i.g: int != 0x77) { return 7; };\n" + " if (x.mark: int != 0x5a) { return 8; };\n" + " return 0;\n" + "};\n", + 0 }, + + /* ctl8 — 8-aligned struct: the MOVQ loop alone, zero tail iterations. + * Proves the 8-aligned emission path stays correct (byte-id caveat). */ + { "ctl8", + "package main;\n" + "type inner8 = struct { a: i64 };\n" + "type outer8 = struct { i: inner8, mark: i64 };\n" + "export fn main() int = {\n" + " let o: inner8 = inner8 { a = 0x1234567 };\n" + " let x: outer8;\n" + " x.mark = 0x76543210;\n" + " x.i = o;\n" + " if (x.i.a != 0x1234567) { return 1; };\n" + " if (x.mark != 0x76543210) { return 2; };\n" + " return 0;\n" + "};\n", + 0 }, +}; + +/* run_build — build+run `src` via `driver`; returns the binary's exit + * code, or -1 on a build failure. */ +static int +run_build(const char *driver, const struct row *r, int i) +{ + char src[64], tmpdir[64], cmd[1024]; + snprintf(src, sizeof src, "/tmp/sctail_%d_%d.ww", getpid(), i); + snprintf(tmpdir, sizeof tmpdir, "/tmp/sctail_%d_d_%d", getpid(), i); + + FILE *f = fopen(src, "wb"); + if (!f) return -2; + fputs(r->src, f); + fclose(f); + + mkdir(tmpdir, 0755); + snprintf(cmd, sizeof cmd, "cd %s && %s build %s 2>/dev/null", + tmpdir, driver, src); + int brc = runwait(cmd); + + const char *base = strrchr(src, '/'); + base = base ? base + 1 : src; + char outbin[128]; + snprintf(outbin, sizeof outbin, "%s/%s", tmpdir, base); + char *dot = strrchr(outbin, '.'); + if (dot && strcmp(dot, ".ww") == 0) *dot = '\0'; + + int got = -1; + if (brc == 0) got = runwait(outbin); + + unlink(src); unlink(outbin); rmdir(tmpdir); + return brc == 0 ? got : -1; +} + +int +main(void) +{ + const char *bin = getenv("BIN"); + if (!bin) bin = "out/bin"; + char absbin[1024]; + if (bin[0] != '/') { + char cwd[1024]; + if (getcwd(cwd, sizeof cwd) == NULL) return 1; + snprintf(absbin, sizeof absbin, "%s/%s", cwd, bin); + bin = absbin; + } + + char cdrv[1024], wdrv[1024]; + snprintf(cdrv, sizeof cdrv, "%s/ww", bin); + snprintf(wdrv, sizeof wdrv, "%s/ww_ww", bin); + int have_ww = (access(wdrv, X_OK) == 0); + + int n = (int)(sizeof rows / sizeof rows[0]); + int total = 0, fail = 0; + + for (int i = 0; i < n; i++) { + total++; + int gc = run_build(cdrv, &rows[i], i); + if (gc < 0) { + fprintf(stderr, "structcopytail_run[cstage][%s]: build/run " + "failed (got %d)\n", rows[i].label, gc); + fail++; + continue; + } + if (rows[i].want_exit >= 0 && gc != rows[i].want_exit) { + fprintf(stderr, "structcopytail_run[cstage][%s]: exit=%d " + "want=%d (field/clobber mismatch)\n", + rows[i].label, gc, rows[i].want_exit); + fail++; + } + if (!have_ww) { + fprintf(stderr, "structcopytail_run: skip wwstage (no %s)\n", + wdrv); + continue; + } + int gw = run_build(wdrv, &rows[i], i); + if (gw != gc) { + fprintf(stderr, "structcopytail_run[%s]: cs=%d != ww=%d " + "(copy-tail divergence — #71)\n", + rows[i].label, gc, gw); + fail++; + } + if (rows[i].want_exit >= 0 && gw != rows[i].want_exit) { + fprintf(stderr, "structcopytail_run[wwstage][%s]: exit=%d " + "want=%d (field/clobber mismatch)\n", + rows[i].label, gw, rows[i].want_exit); + fail++; + } + } + + if (fail) { + fprintf(stderr, "structcopytail_run: %d/%d checks failed\n", + fail, total); + return 1; + } + printf("structcopytail_run: %d/%d ok\n", total, total); + return 0; +}