aboutsummaryrefslogtreecommitdiff
path: root/src/backend/rv64/abi.cc
diff options
context:
space:
mode:
Diffstat (limited to 'src/backend/rv64/abi.cc')
-rw-r--r--src/backend/rv64/abi.cc690
1 files changed, 690 insertions, 0 deletions
diff --git a/src/backend/rv64/abi.cc b/src/backend/rv64/abi.cc
new file mode 100644
index 0000000..6456c21
--- /dev/null
+++ b/src/backend/rv64/abi.cc
@@ -0,0 +1,690 @@
+/* Source code for RCC-Legacy.
+ Copyright (C) 2026 Richard Qin
+
+This file is part of RCC.
+
+RCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+RCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with RCC; see the file LICENSE. If not see
+<http://www.gnu.org/licenses/>. */
+
+/// @file abi.cc
+/// @brief RISC-V lp64d ABI lowering.
+
+#include "rcc/rv64.h"
+
+namespace rcc {
+
+namespace {
+
+// ABI classification flags (OR-able).
+enum : int {
+ kCptr = 1, // Pointer to large struct.
+ kCstk1 = 2, // First XLEN on stack.
+ kCstk2 = 4, // Second XLEN on stack.
+ kCstk = kCstk1 | kCstk2,
+ kCfpint = 8, // Float in GP reg.
+};
+
+// Argument class.
+struct ArgClass {
+ int flags; // OR of kCptr / kCstk1 / kCstk2 / kCfpint
+ Typ* type;
+ int reg[2];
+ int cls[2];
+ int off[2];
+ int ngp; // Written by typclass
+ int nfp;
+ int nreg;
+};
+
+struct Insl {
+ Insl* link;
+ Ins i;
+};
+
+struct Params {
+ int ngp;
+ int nfp;
+ int stk;
+};
+
+// Registers. Sentinels of 0 are used to prevent out-of-bounds reads.
+constexpr int kGpReg[10] = {A0, A1, A2, A3, A4, A5, A6, A7, 0, 0};
+constexpr int kFpReg[10] = {FA0, FA1, FA2, FA3, FA4, FA5, FA6, FA7, 0, 0};
+
+} // namespace
+
+// RCall encoding.
+
+bits rv64_retregs(Ref r, int p[2]) {
+ assert(rtype(r) == RCall);
+ int ngp = static_cast<int>(r.val & 3);
+ int nfp = static_cast<int>((r.val >> 2) & 3);
+ if (p) {
+ p[0] = ngp;
+ p[1] = nfp;
+ }
+ bits b = 0;
+ for (int i = 0; i < ngp; ++i)
+ b |= BIT(A0 + i);
+ for (int i = 0; i < nfp; ++i)
+ b |= BIT(FA0 + i);
+ return b;
+}
+
+bits rv64_argregs(Ref r, int p[2]) {
+ assert(rtype(r) == RCall);
+ int ngp = static_cast<int>((r.val >> 4) & 15);
+ int nfp = static_cast<int>((r.val >> 8) & 15);
+ int t5 = static_cast<int>((r.val >> 12) & 1);
+ if (p) {
+ p[0] = ngp + t5;
+ p[1] = nfp;
+ }
+ bits b = 0;
+ for (int i = 0; i < ngp; ++i)
+ b |= BIT(A0 + i);
+ for (int i = 0; i < nfp; ++i)
+ b |= BIT(FA0 + i);
+ if (t5)
+ b |= BIT(T5);
+ return b;
+}
+
+namespace {
+
+// HFA-style floating-point struct classification.
+
+int classify_fpstruct(Typ* t, int off, ArgClass* c) {
+ if (t->isunion)
+ return -1;
+
+ for (Field* f = *t->fields; f->type != Field::FEnd; ++f) {
+ if (f->type == Field::FPad) {
+ off += static_cast<int>(f->len);
+ continue;
+ }
+ if (f->type == Field::FTyp) {
+ if (classify_fpstruct(&typ[f->len], off, c) == -1)
+ return -1;
+ continue;
+ }
+
+ int slot = c->nfp + c->ngp;
+ if (slot == 2)
+ return -1;
+
+ switch (f->type) {
+ case Field::Fb:
+ case Field::Fh:
+ case Field::Fw:
+ c->cls[slot] = Kw;
+ ++c->ngp;
+ break;
+ case Field::Fl:
+ c->cls[slot] = Kl;
+ ++c->ngp;
+ break;
+ case Field::Fs:
+ c->cls[slot] = Ks;
+ ++c->nfp;
+ break;
+ case Field::Fd:
+ c->cls[slot] = Kd;
+ ++c->nfp;
+ break;
+ default:
+ die("classify_fpstruct: unexpected field type");
+ }
+ c->off[slot] = off;
+ off += static_cast<int>(f->len);
+ }
+ return c->nfp;
+}
+
+// Determine ABI class for struct t.
+void typclass(ArgClass* c, Typ* t, int fpabi, const int* gp, const int* fp) {
+ c->type = t;
+ c->flags = 0;
+ c->ngp = 0;
+ c->nfp = 0;
+
+ if (t->align > 4)
+ err(const_cast<char*>("alignments larger than 16 are not supported"));
+
+ if (t->isdark || t->size > 16 || t->size == 0) {
+ // Large or dark: pass by pointer.
+ c->flags |= kCptr;
+ c->cls[0] = Kl;
+ c->off[0] = 0;
+ c->ngp = 1;
+ } else if (!fpabi || classify_fpstruct(t, 0, c) <= 0) {
+ // GP-only word packing.
+ uint n = 0;
+ while (8 * n < t->size) {
+ c->cls[n] = Kl;
+ c->off[n] = static_cast<int>(8 * n);
+ ++n;
+ }
+ c->nfp = 0;
+ c->ngp = static_cast<int>(n);
+ }
+
+ c->nreg = c->nfp + c->ngp;
+ for (int i = 0; i < c->nreg; ++i) {
+ if (KBASE(c->cls[i]) == 0)
+ c->reg[i] = *gp++;
+ else
+ c->reg[i] = *fp++;
+ }
+}
+
+// Store tmp to mem+off.
+void sttmps(Ctx* ctx, Ref tmp[], int ntmp, ArgClass* c, Ref mem, Fn* fn) {
+ static constexpr auto kStOp = [] {
+ std::array<int, 4> a{};
+ a[Kw] = Ostorew;
+ a[Kl] = Ostorel;
+ a[Ks] = Ostores;
+ a[Kd] = Ostored;
+ return a;
+ }();
+ assert(ntmp > 0 && ntmp <= 2);
+ for (int i = 0; i < ntmp; ++i) {
+ tmp[i] = newtmp(ctx, "abi", c->cls[i], fn);
+ Ref addr = newtmp(ctx, "abi", Kl, fn);
+ emit(ctx, kStOp[static_cast<size_t>(c->cls[i])], 0, Ref::none(), tmp[i], addr);
+ emit(ctx, Oadd, Kl, addr, mem, getcon(ctx, c->off[i], fn));
+ }
+}
+
+// Load mem+off to regs.
+void ldregs(Ctx* ctx, ArgClass* c, Ref mem, Fn* fn) {
+ for (int i = 0; i < c->nreg; ++i) {
+ Ref addr = newtmp(ctx, "abi", Kl, fn);
+ emit(ctx, Oload, c->cls[i], Ref::tmp(static_cast<uint>(c->reg[i])), addr, Ref::none());
+ emit(ctx, Oadd, Kl, addr, mem, getcon(ctx, c->off[i], fn));
+ }
+}
+
+// Return value lowering.
+
+void selret(Ctx* ctx, Blk* b, Fn* fn) {
+ int j = b->jmp.type;
+ if (!isret(j) || j == Jret0)
+ return;
+
+ Ref r = b->jmp.arg;
+ b->jmp.type = Jret0;
+
+ int cty;
+ if (j == Jretc) {
+ ArgClass cr{};
+ typclass(&cr, &typ[fn->retty], 1, kGpReg, kFpReg);
+ if (cr.flags & kCptr) {
+ assert(rtype(fn->retr) == RTmp);
+ emit(ctx, Oblit1, 0, Ref::none(), Ref::integer(static_cast<int>(cr.type->size)),
+ Ref::none());
+ emit(ctx, Oblit0, 0, Ref::none(), r, fn->retr);
+ cty = 0;
+ } else {
+ ldregs(ctx, &cr, r, fn);
+ cty = (cr.nfp << 2) | cr.ngp;
+ }
+ } else {
+ int k = j - Jretw;
+ if (KBASE(k) == 0) {
+ emit(ctx, Ocopy, k, Ref::tmp(A0), r, Ref::none());
+ cty = 1;
+ } else {
+ emit(ctx, Ocopy, k, Ref::tmp(FA0), r, Ref::none());
+ cty = 1 << 2;
+ }
+ }
+
+ b->jmp.arg = Ref::call(static_cast<uint>(cty));
+}
+
+// Arg/par classification.
+
+int argsclass(Ins* i0, Ins* i1, ArgClass* carg, int retptr) {
+ const int* gp = kGpReg;
+ const int* fp = kFpReg;
+ int ngp = 8, nfp = 8;
+ bool vararg = false, envc = false;
+
+ if (retptr) {
+ ++gp;
+ --ngp;
+ }
+
+ ArgClass* c = carg;
+ for (Ins* i = i0; i < i1; ++i, ++c) {
+ switch (i->op) {
+ case Opar:
+ case Oarg:
+ c->cls[0] = static_cast<int>(i->cls);
+ if (!vararg && KBASE(i->cls) == 1 && nfp > 0) {
+ --nfp;
+ c->reg[0] = *fp++;
+ } else if (ngp > 0) {
+ if (KBASE(i->cls) == 1)
+ c->flags |= kCfpint;
+ --ngp;
+ c->reg[0] = *gp++;
+ } else {
+ c->flags |= kCstk1;
+ }
+ break;
+
+ case Oargv:
+ vararg = true;
+ break;
+
+ case Oparc:
+ case Oargc: {
+ Typ* t = &typ[i->arg[0].val];
+ typclass(c, t, 1, gp, fp);
+ if (c->nfp > 0 && (c->nfp >= nfp || c->ngp >= ngp)) {
+ // Downgrade to GP-only.
+ typclass(c, t, 0, gp, fp);
+ }
+ assert(c->nfp <= nfp);
+ if (c->ngp <= ngp) {
+ ngp -= c->ngp;
+ nfp -= c->nfp;
+ gp += c->ngp;
+ fp += c->nfp;
+ } else if (ngp > 0) {
+ // First word in GP, second on stack.
+ assert(c->ngp == 2);
+ assert(c->flags == 0);
+ c->flags |= kCstk2;
+ c->nreg = 1;
+ --ngp;
+ ++gp;
+ } else {
+ c->flags |= kCstk1;
+ if (c->nreg > 1)
+ c->flags |= kCstk2;
+ c->nreg = 0;
+ }
+ break;
+ }
+
+ case Opare:
+ case Oarge:
+ c->reg[0] = T5;
+ c->cls[0] = Kl;
+ envc = true;
+ break;
+ }
+ }
+
+ int passgp = static_cast<int>(gp - kGpReg);
+ int passfp = static_cast<int>(fp - kFpReg);
+ return ((envc ? 1 : 0) << 12) | (passgp << 4) | (passfp << 8);
+}
+
+// Prepend Oalloc to start block.
+void stkblob(Ctx* ctx, Ref r, Typ* t, Fn* fn, Insl** ilp) {
+ Insl* il = static_cast<Insl*>(alloc(ctx, sizeof(*il)));
+ int al = t->align - 2; // alignment logic.
+ if (al < 0)
+ al = 0;
+ uint64_t sz = (t->size + 7) & ~static_cast<uint64_t>(7);
+
+ Ins ins = {};
+ ins.op = static_cast<uint>(Oalloc + al);
+ ins.cls = Kl;
+ ins.to = r;
+ ins.arg[0] = getcon(ctx, static_cast<int64_t>(sz), fn);
+ il->i = ins;
+ il->link = *ilp;
+ *ilp = il;
+}
+
+// Call lowering.
+
+void selcall(Ctx* ctx, Fn* fn, Ins* i0, Ins* i1, Insl** ilp) {
+ ArgClass* ca =
+ static_cast<ArgClass*>(alloc(ctx, static_cast<size_t>(i1 - i0) * sizeof(ArgClass)));
+ for (Ins* z = i0; z < i1; ++z)
+ ca[z - i0] = {};
+ ArgClass cr{};
+
+ if (!req(i1->arg[1], Ref::none())) {
+ typclass(&cr, &typ[i1->arg[1].val], 1, kGpReg, kFpReg);
+ }
+
+ int cty = argsclass(i0, i1, ca, cr.flags & kCptr);
+
+ // compute stk and replace large struct args with pointer.
+ uint64_t stk = 0;
+ {
+ ArgClass* c = ca;
+ for (Ins* i = i0; i < i1; ++i, ++c) {
+ if (i->op == Oargv)
+ continue;
+ if (c->flags & kCptr) {
+ i->arg[0] = newtmp(ctx, "abi", Kl, fn);
+ stkblob(ctx, i->arg[0], c->type, fn, ilp);
+ i->op = Oarg;
+ }
+ if (c->flags & kCstk1)
+ stk += 8;
+ if (c->flags & kCstk2)
+ stk += 8;
+ }
+ stk += stk & 15; // 16B align tail
+ }
+ if (stk)
+ emit(ctx, Osalloc, Kl, Ref::none(), getcon(ctx, -static_cast<int64_t>(stk), fn),
+ Ref::none());
+
+ // Emit instructions backwards.
+ Ref tmp[2];
+ if (!req(i1->arg[1], Ref::none())) {
+ stkblob(ctx, i1->to, cr.type, fn, ilp);
+ cty |= (cr.nfp << 2) | cr.ngp;
+ if (cr.flags & kCptr) {
+ // Dummy Ocopy.
+ emit(ctx, Ocopy, Kw, Ref::none(), Ref::tmp(A0), Ref::none());
+ } else {
+ sttmps(ctx, tmp, cr.nreg, &cr, i1->to, fn);
+ for (int j = 0; j < cr.nreg; ++j) {
+ Ref rreg = Ref::tmp(static_cast<uint>(cr.reg[j]));
+ emit(ctx, Ocopy, cr.cls[j], tmp[j], rreg, Ref::none());
+ }
+ }
+ } else if (KBASE(i1->cls) == 0) {
+ emit(ctx, Ocopy, i1->cls, i1->to, Ref::tmp(A0), Ref::none());
+ cty |= 1;
+ } else {
+ emit(ctx, Ocopy, i1->cls, i1->to, Ref::tmp(FA0), Ref::none());
+ cty |= 1 << 2;
+ }
+
+ emit(ctx, Ocall, 0, Ref::none(), i1->arg[0], Ref::call(static_cast<uint>(cty)));
+
+ if (cr.flags & kCptr) {
+ // Cptr return logic.
+ emit(ctx, Ocopy, Kl, Ref::tmp(A0), i1->to, Ref::none());
+ }
+
+ // move args to regs.
+ {
+ ArgClass* c = ca;
+ for (Ins* i = i0; i < i1; ++i, ++c) {
+ if (i->op == Oargv || (c->flags & kCstk1))
+ continue;
+ if (i->op == Oargc) {
+ ldregs(ctx, c, i->arg[1], fn);
+ } else if (c->flags & kCfpint) {
+ int k = KWIDE(c->cls[0]) ? Kl : Kw;
+ Ref r = newtmp(ctx, "abi", k, fn);
+ emit(ctx, Ocopy, k, Ref::tmp(static_cast<uint>(c->reg[0])), r, Ref::none());
+ c->reg[0] = static_cast<int>(r.val);
+ } else {
+ emit(ctx, Ocopy, c->cls[0], Ref::tmp(static_cast<uint>(c->reg[0])), i->arg[0],
+ Ref::none());
+ }
+ }
+ }
+
+ // casts and blits.
+ {
+ ArgClass* c = ca;
+ for (Ins* i = i0; i < i1; ++i, ++c) {
+ if (c->flags & kCfpint) {
+ int k = KWIDE(c->cls[0]) ? Kl : Kw;
+ emit(ctx, Ocast, k, Ref::tmp(static_cast<uint>(c->reg[0])), i->arg[0], Ref::none());
+ }
+ if (c->flags & kCptr) {
+ emit(ctx, Oblit1, 0, Ref::none(), Ref::integer(static_cast<int>(c->type->size)),
+ Ref::none());
+ emit(ctx, Oblit0, 0, Ref::none(), i->arg[1], i->arg[0]);
+ }
+ }
+ }
+
+ if (!stk)
+ return;
+
+ // move stack args to slot.
+ uint64_t off = 0;
+ Ref sp = newtmp(ctx, "abi", Kl, fn);
+ {
+ ArgClass* c = ca;
+ for (Ins* i = i0; i < i1; ++i, ++c) {
+ if (i->op == Oargv || !(c->flags & kCstk))
+ continue;
+ if (i->op == Oarg) {
+ Ref addr = newtmp(ctx, "abi", Kl, fn);
+ emit(ctx, Ostorew + i->cls, Kw, Ref::none(), i->arg[0], addr);
+ if (i->cls == Kw) {
+ // TODO: check if sext is needed.
+ ctx->curi->op = Ostorel;
+ ctx->curi->arg[0] = newtmp(ctx, "abi", Kl, fn);
+ emit(ctx, Oextsw, Kl, ctx->curi->arg[0], i->arg[0], Ref::none());
+ }
+ emit(ctx, Oadd, Kl, addr, sp, getcon(ctx, static_cast<int64_t>(off), fn));
+ off += 8;
+ }
+ if (i->op == Oargc) {
+ if (c->flags & kCstk1) {
+ Ref addr = newtmp(ctx, "abi", Kl, fn);
+ Ref val = newtmp(ctx, "abi", Kl, fn);
+ emit(ctx, Ostorel, 0, Ref::none(), val, addr);
+ emit(ctx, Oadd, Kl, addr, sp, getcon(ctx, static_cast<int64_t>(off), fn));
+ emit(ctx, Oload, Kl, val, i->arg[1], Ref::none());
+ off += 8;
+ }
+ if (c->flags & kCstk2) {
+ Ref addr = newtmp(ctx, "abi", Kl, fn);
+ Ref val = newtmp(ctx, "abi", Kl, fn);
+ emit(ctx, Ostorel, 0, Ref::none(), val, addr);
+ emit(ctx, Oadd, Kl, addr, sp, getcon(ctx, static_cast<int64_t>(off), fn));
+ Ref addr2 = newtmp(ctx, "abi", Kl, fn);
+ emit(ctx, Oload, Kl, val, addr2, Ref::none());
+ emit(ctx, Oadd, Kl, addr2, i->arg[1], getcon(ctx, 8, fn));
+ off += 8;
+ }
+ }
+ }
+ }
+ emit(ctx, Osalloc, Kl, sp, getcon(ctx, static_cast<int64_t>(stk), fn), Ref::none());
+}
+
+// Par lowering.
+
+Params selpar(Ctx* ctx, Fn* fn, Ins* i0, Ins* i1) {
+ ArgClass* ca =
+ static_cast<ArgClass*>(alloc(ctx, static_cast<size_t>(i1 - i0) * sizeof(ArgClass)));
+ for (Ins* z = i0; z < i1; ++z)
+ ca[z - i0] = {};
+ ArgClass cr{};
+ ctx->curi = &ctx->insb[NIns];
+
+ if (fn->retty >= 0) {
+ typclass(&cr, &typ[fn->retty], 1, kGpReg, kFpReg);
+ if (cr.flags & kCptr) {
+ fn->retr = newtmp(ctx, "abi", Kl, fn);
+ emit(ctx, Ocopy, Kl, fn->retr, Ref::tmp(A0), Ref::none());
+ }
+ }
+
+ int cty = argsclass(i0, i1, ca, cr.flags & kCptr);
+ fn->reg = rv64_argregs(Ref::call(static_cast<uint>(cty)), nullptr);
+
+ // slot allocations and Ocast.
+ Insl* il = nullptr;
+ Ref tmp[17];
+ Ref* t = tmp;
+ {
+ ArgClass* c = ca;
+ for (Ins* i = i0; i < i1; ++i, ++c) {
+ if (c->flags & kCfpint) {
+ Ref to_orig = i->to;
+ int k = c->cls[0];
+ c->cls[0] = KWIDE(k) ? Kl : Kw;
+ i->to = newtmp(ctx, "abi", k, fn);
+ emit(ctx, Ocast, k, to_orig, i->to, Ref::none());
+ }
+ if (i->op == Oparc && !(c->flags & kCptr) && c->nreg != 0) {
+ int nt = c->nreg;
+ if (c->flags & kCstk2) {
+ c->cls[1] = Kl;
+ c->off[1] = 8;
+ assert(nt == 1);
+ nt = 2;
+ }
+ sttmps(ctx, t, nt, c, i->to, fn);
+ stkblob(ctx, i->to, c->type, fn, &il);
+ t += nt;
+ }
+ }
+ }
+ for (; il; il = il->link)
+ emiti(ctx, il->i);
+
+ // copy from regs or load from slot.
+ t = tmp;
+ int s = 2 + 8 * fn->vararg;
+ {
+ ArgClass* c = ca;
+ for (Ins* i = i0; i < i1; ++i, ++c) {
+ if (i->op == Oparc && !(c->flags & kCptr)) {
+ if (c->nreg == 0) {
+ fn->tmp[i->to.val].slot = -s;
+ s += (c->flags & kCstk2) ? 2 : 1;
+ continue;
+ }
+ for (int j = 0; j < c->nreg; ++j) {
+ Ref rreg = Ref::tmp(static_cast<uint>(c->reg[j]));
+ emit(ctx, Ocopy, c->cls[j], *t++, rreg, Ref::none());
+ }
+ if (c->flags & kCstk2) {
+ emit(ctx, Oload, Kl, *t, Ref::slot(-s), Ref::none());
+ ++t;
+ ++s;
+ }
+ } else if (c->flags & kCstk1) {
+ emit(ctx, Oload, c->cls[0], i->to, Ref::slot(-s), Ref::none());
+ ++s;
+ } else {
+ emit(ctx, Ocopy, c->cls[0], i->to, Ref::tmp(static_cast<uint>(c->reg[0])),
+ Ref::none());
+ }
+ }
+ }
+
+ Params p;
+ p.stk = s;
+ p.ngp = (cty >> 4) & 15;
+ p.nfp = (cty >> 8) & 15;
+ return p;
+}
+
+// Varargs.
+
+void selvaarg(Ctx* ctx, Fn* fn, Ins* i) {
+ Ref loc = newtmp(ctx, "abi", Kl, fn);
+ Ref newloc = newtmp(ctx, "abi", Kl, fn);
+ emit(ctx, Ostorel, Kw, Ref::none(), newloc, i->arg[0]);
+ emit(ctx, Oadd, Kl, newloc, loc, getcon(ctx, 8, fn));
+ emit(ctx, Oload, i->cls, i->to, loc, Ref::none());
+ emit(ctx, Oload, Kl, loc, i->arg[0], Ref::none());
+}
+
+void selvastart(Ctx* ctx, Fn* fn, Params p, Ref ap) {
+ Ref rsave = newtmp(ctx, "abi", Kl, fn);
+ emit(ctx, Ostorel, Kw, Ref::none(), rsave, ap);
+ int s = p.stk > 2 + 8 * fn->vararg ? p.stk : 2 + p.ngp;
+ emit(ctx, Oaddr, Kl, rsave, Ref::slot(-s), Ref::none());
+}
+
+} // namespace
+
+// Entry point.
+
+void rv64_abi(Ctx* ctx, Fn* fn) {
+ for (Blk* b = fn->start; b; b = b->link)
+ b->visit = 0;
+
+ // Lower parameters.
+ Blk* b = fn->start;
+ Ins* end = &b->ins[b->nins];
+ Ins* i = b->ins;
+ while (i < end && ispar(i->op))
+ ++i;
+ Params p = selpar(ctx, fn, b->ins, i);
+
+ int n0 = static_cast<int>(&ctx->insb[NIns] - ctx->curi);
+ int ioff = static_cast<int>(i - b->ins);
+ int n1 = static_cast<int>(b->nins) - ioff;
+ vgrow(ctx, &b->ins, static_cast<ulong>(n0 + n1));
+ icpy(b->ins + n0, b->ins + ioff, static_cast<ulong>(n1));
+ icpy(b->ins, ctx->curi, static_cast<ulong>(n0));
+ b->nins = static_cast<uint>(n0 + n1);
+
+ // Lower calls/returns/varargs.
+ Insl* il = nullptr;
+ b = fn->start;
+ do {
+ b = b->link ? b->link : fn->start;
+ if (b->visit)
+ continue;
+ ctx->curi = &ctx->insb[NIns];
+ selret(ctx, b, fn);
+
+ for (Ins* it = &b->ins[b->nins]; it != b->ins;) {
+ --it;
+ switch (it->op) {
+ default:
+ emiti(ctx, *it);
+ break;
+ case Ocall: {
+ Ins* lo = it;
+ while (lo > b->ins && isarg((lo - 1)->op))
+ --lo;
+ selcall(ctx, fn, lo, it, &il);
+ it = lo;
+ break;
+ }
+ case Ovastart:
+ selvastart(ctx, fn, p, it->arg[0]);
+ break;
+ case Ovaarg:
+ selvaarg(ctx, fn, it);
+ break;
+ case Oarg:
+ case Oargc:
+ die("rv64_abi: Oarg/Oargc unreachable");
+ }
+ }
+
+ if (b == fn->start) {
+ for (; il; il = il->link)
+ emiti(ctx, il->i);
+ }
+ idup(ctx, b, ctx->curi, static_cast<ulong>(&ctx->insb[NIns] - ctx->curi));
+ } while (b != fn->start);
+
+ if (debug['A']) {
+ fprintf(ctx->dbg_buf, "\n> After ABI lowering:\n");
+ printfn(fn, ctx->dbg_buf);
+ }
+}
+
+} // namespace rcc
generated by cgit v1.2.3 (git 2.46.0) at 2026-10-29 13:26:11 +0000