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make variadic args explicit

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Some abis, like the riscv one, treat
arguments differently depending on
whether they are variadic or not.
To prepare for the upcomming riscv
target, we change the variadic call
syntax and give meaning to the
location of the '...' marker.

  # new syntax
  %ret =w call $f(w %regular, ..., w %variadic)

By nature of their abis, the change
is backwards compatible for existing
targets.
This commit is contained in:
Quentin Carbonneaux 2021-10-18 21:04:10 +02:00
parent 9858a12730
commit fcdef10dae
13 changed files with 101 additions and 75 deletions
Download patch file Download diff file Expand all files Collapse all files

34
amd64/sysv.c
View file

@ -153,7 +153,7 @@ selret(Blk *b, Fn *fn)
static int
argsclass(Ins *i0, Ins *i1, AClass *ac, int op, AClass *aret, Ref *env)
{
int nint, ni, nsse, ns, n, *pn;
int varc, envc, nint, ni, nsse, ns, n, *pn;
AClass *a;
Ins *i;
@ -162,6 +162,8 @@ argsclass(Ins *i0, Ins *i1, AClass *ac, int op, AClass *aret, Ref *env)
else
nint = 6;
nsse = 8;
varc = 0;
envc = 0;
for (i=i0, a=ac; i<i1; i++, a++)
switch (i->op - op + Oarg) {
case Oarg:
@ -196,14 +198,23 @@ argsclass(Ins *i0, Ins *i1, AClass *ac, int op, AClass *aret, Ref *env)
a->inmem = 1;
break;
case Oarge:
envc = 1;
if (op == Opar)
*env = i->to;
else
*env = i->arg[0];
break;
case Oargv:
varc = 1;
break;
default:
die("unreachable");
}
return (!req(R, *env) << 12) | ((6-nint) << 4) | ((8-nsse) << 8);
if (varc && envc)
err("sysv abi does not support variadic env calls");
return ((varc|envc) << 12) | ((6-nint) << 4) | ((8-nsse) << 8);
}
int amd64_sysv_rsave[] = {
@ -290,7 +301,7 @@ selcall(Fn *fn, Ins *i0, Ins *i1, RAlloc **rap)
{
Ins *i;
AClass *ac, *a, aret;
int ca, ni, ns, al, varc, envc;
int ca, ni, ns, al;
uint stk, off;
Ref r, r1, r2, reg[2], env;
RAlloc *ra;
@ -358,22 +369,20 @@ selcall(Fn *fn, Ins *i0, Ins *i1, RAlloc **rap)
ca += 1 << 2;
}
}
envc = !req(R, env);
varc = i1->op == Ovacall;
if (varc && envc)
err("sysv abi does not support variadic env calls");
ca |= varc << 12; /* envc set in argsclass() */
emit(Ocall, i1->cls, R, i1->arg[0], CALL(ca));
if (envc)
if (!req(R, env))
emit(Ocopy, Kl, TMP(RAX), env, R);
if (varc)
else if ((ca >> 12) & 1) /* vararg call */
emit(Ocopy, Kw, TMP(RAX), getcon((ca >> 8) & 15, fn), R);
ni = ns = 0;
if (ra && aret.inmem)
emit(Ocopy, Kl, rarg(Kl, &ni, &ns), ra->i.to, R); /* pass hidden argument */
for (i=i0, a=ac; i<i1; i++, a++) {
if (a->inmem || i->op == Oarge)
if (i->op >= Oarge || a->inmem)
continue;
r1 = rarg(a->cls[0], &ni, &ns);
if (i->op == Oargc) {
@ -393,7 +402,7 @@ selcall(Fn *fn, Ins *i0, Ins *i1, RAlloc **rap)
r = newtmp("abi", Kl, fn);
for (i=i0, a=ac, off=0; i<i1; i++, a++) {
if (!a->inmem)
if (i->op >= Oarge || !a->inmem)
continue;
if (i->op == Oargc) {
if (a->align == 4)
@ -676,7 +685,6 @@ amd64_sysv_abi(Fn *fn)
emiti(*i);
break;
case Ocall:
case Ovacall:
for (i0=i; i0>b->ins; i0--)
if (!isarg((i0-1)->op))
break;