extern DYNCONST

This commit is contained in:
Quentin Carbonneaux 2026-04-27 16:32:28 +02:00
parent dba8d5a4bf
commit 7ab2fbe07c
8 changed files with 128 additions and 14 deletions

11
all.h
View File

@ -292,9 +292,16 @@ struct Use {
};
struct Sym {
/* SGlo = 0 (direct access)
* SThr = 1 (local-exec TLS)
* SExt = 2 (GOT/PLT access)
* SExt|SThr = 3 (initial-exec TLS)
*/
enum {
SGlo,
SThr,
SGlo = 0,
SThr = 1,
SExt = 2,
SExtThr = SExt|SThr,
} type;
uint32_t id;
};

View File

@ -195,7 +195,7 @@ emitcon(Con *con, E *e)
case CAddr:
l = str(con->sym.id);
p = l[0] == '"' ? "" : T.assym;
if (con->sym.type == SThr) {
if (con->sym.type & SThr) {
if (T.apple)
fprintf(e->f, "%s%s@TLVP", p, l);
else
@ -551,14 +551,48 @@ emitins(Ins i, E *e)
regtoa(i.to.val, SLong));
break;
}
if (rtype(i.arg[0]) == RCon
&& e->fn->con[i.arg[0].val].sym.type == SExt) {
/* load address from the GOT */
assert(isreg(i.to));
con = &e->fn->con[i.arg[0].val];
sym = str(con->sym.id);
assert(!con->bits.i);
fprintf(e->f,
"\tmovq %s%s@GOTPCREL(%%rip), %%%s\n",
sym[0] == '"' ? "" : T.assym, sym,
regtoa(i.to.val, SLong));
break;
}
if (!T.apple
&& rtype(i.arg[0]) == RCon
&& e->fn->con[i.arg[0].val].sym.type == SExtThr) {
/* initial-exec TLS: load offset from
* GOT, add to thread-base register */
assert(isreg(i.to));
con = &e->fn->con[i.arg[0].val];
sym = str(con->sym.id);
assert(!con->bits.i);
emitf("movq %%fs:0, %L=", &i, e);
fprintf(e->f,
"\taddq %s%s@gottpoff(%%rip), %%%s\n",
sym[0] == '"' ? "" : T.assym, sym,
regtoa(i.to.val, SLong));
break;
}
goto Table;
case Ocall:
/* calls simply have a weird syntax in AT&T
* assembly... */
switch (rtype(i.arg[0])) {
case RCon:
con = &e->fn->con[i.arg[0].val];
fprintf(e->f, "\tcallq ");
emitcon(&e->fn->con[i.arg[0].val], e);
emitcon(con, e);
if (con->type == CAddr
&& (con->sym.type & SExt)
&& !T.apple)
fprintf(e->f, "@PLT");
fprintf(e->f, "\n");
break;
case RTmp:

View File

@ -120,8 +120,34 @@ fixarg(Ref *r, int k, Ins *i, Fn *fn)
r1 = newtmp("isel", Kl, fn);
emit(Oaddr, Kl, r1, SLOT(s), R);
}
else if (op != Ocall && hascon(r0, &c, fn)
&& c->type == CAddr && (c->sym.type & SExt)
&& (!T.apple || c->sym.type == SExt)) {
/* extern symbols need indirection
* through the GOT
*/
r1 = newtmp("isel", Kl, fn);
if (c->bits.i) {
r2 = newtmp("isel", Kl, fn);
cc = (Con){.type = CBits};
cc.bits.i = c->bits.i;
r3 = newcon(&cc, fn);
emit(Oadd, Kl, r1, r2, r3);
} else
r2 = r1;
cc = *c;
cc.bits.i = 0;
r3 = newcon(&cc, fn);
emit(Oaddr, Kl, r2, r3, R);
if (rtype(r0) == RMem) {
m = &fn->mem[r0.val];
m->offset.type = CUndef;
m->base = r1;
r1 = r0;
}
}
else if (T.apple && hascon(r0, &c, fn)
&& c->type == CAddr && c->sym.type == SThr) {
&& c->type == CAddr && (c->sym.type & SThr)) {
r1 = newtmp("isel", Kl, fn);
if (c->bits.i) {
r2 = newtmp("isel", Kl, fn);

View File

@ -287,6 +287,17 @@ loadaddr(Con *c, char *rn, E *e)
"\tadd\tR, R, #:tprel_hi12:SO, lsl #12\n"
"\tadd\tR, R, #:tprel_lo12_nc:SO\n";
break;
case SExt:
if (T.apple)
s = "\tadrp\tR, S@gotpageO\n"
"\tldr\tR, [R, S@gotpageoffO]\n";
else
s = "\tadrp\tR, :got:SO\n"
"\tldr\tR, [R, #:got_lo12:SO]\n";
break;
case SExtThr:
die("extern thread not yet implemented on arm64");
break;
}
l = str(c->sym.id);
@ -468,7 +479,7 @@ emitins(Ins *i, E *e)
goto Table;
c = &e->fn->con[i->arg[0].val];
if (c->type != CAddr
|| c->sym.type != SGlo
|| (c->sym.type & SThr)
|| c->bits.i)
die("invalid call argument");
l = str(c->sym.id);

View File

@ -180,7 +180,9 @@ by zero-extension, or by sign-extension.
DYNCONST :=
CONST
| 'thread' $IDENT # Thread-local symbol
| 'thread' $IDENT # Thread-local symbol
| 'extern' $IDENT # Extern symbol (GOT)
| 'extern' 'thread' $IDENT # Extern thread-local (initial-exec)
VAL :=
DYNCONST
@ -225,6 +227,16 @@ When the `thread` keyword prefixes a symbol name, the
symbol's numeric value is resolved at runtime in the
thread-local storage.
When the `extern` keyword prefixes a symbol name, the
symbol is accessed indirectly through the Global Offset
Table (GOT). Function calls to extern symbols use the
Procedure Linkage Table (PLT). This enables PIE and
PIC code generation for symbols that are not part of
the main executable. When `extern` is combined with
`thread`, the symbol is accessed using the initial-exec
TLS model, suitable for thread-local variables defined
in shared libraries.
Vals are used as arguments in regular, phi, and jump
instructions within function definitions. They are
either constants or function-scope temporaries.

15
parse.c
View File

@ -57,6 +57,7 @@ enum Token {
Thlt,
Texport,
Tthread,
Textern,
Tcommon,
Tfunc,
Ttype,
@ -116,6 +117,7 @@ static char *kwmap[Ntok] = {
[Thlt] = "hlt",
[Texport] = "export",
[Tthread] = "thread",
[Textern] = "extern",
[Tcommon] = "common",
[Tfunc] = "function",
[Ttype] = "type",
@ -448,11 +450,20 @@ parseref()
c.bits.d = tokval.fltd;
c.flt = 2;
break;
case Textern:
c.sym.type = SExt;
if (peek() == Tthread) {
next();
c.sym.type |= SThr;
}
expect(Tglo);
goto Glo;
case Tthread:
c.sym.type = SThr;
expect(Tglo);
/* fall through */
case Tglo:
Glo:
c.type = CAddr;
c.sym.id = intern(tokval.str);
break;
@ -1255,7 +1266,9 @@ printcon(Con *c, FILE *f)
case CUndef:
break;
case CAddr:
if (c->sym.type == SThr)
if (c->sym.type & SExt)
fprintf(f, "extern ");
if (c->sym.type & SThr)
fprintf(f, "thread ");
fprintf(f, "$%s", str(c->sym.id));
if (c->bits.i)

View File

@ -131,7 +131,7 @@ slot(Ref r, Fn *fn)
static void
emitaddr(Con *c, FILE *f)
{
assert(c->sym.type == SGlo);
assert(c->sym.type == SGlo || c->sym.type == SExt);
fputs(str(c->sym.id), f);
if (c->bits.i)
fprintf(f, "+%"PRIi64, c->bits.i);
@ -231,7 +231,8 @@ loadaddr(Con *c, char *rn, FILE *f)
{
char off[32];
if (c->sym.type == SThr) {
switch (c->sym.type) {
case SThr:
if (c->bits.i)
sprintf(off, "+%"PRIi64, c->bits.i);
else
@ -242,10 +243,20 @@ loadaddr(Con *c, char *rn, FILE *f)
rn, rn, str(c->sym.id), off);
fprintf(f, "\taddi %s, %s, %%tprel_lo(%s)%s\n",
rn, rn, str(c->sym.id), off);
} else {
break;
case SExt:
fprintf(f, "\tla %s, ", rn);
emitaddr(c, f);
fputc('\n', f);
break;
case SExtThr:
die("extern thread not yet implemented on rv64");
break;
default:
fprintf(f, "\tla %s, ", rn);
emitaddr(c, f);
fputc('\n', f);
break;
}
}
@ -282,7 +293,7 @@ fixmem(Ref *pr, Fn *fn, FILE *f)
if (rtype(r) == RCon) {
c = &fn->con[r.val];
if (c->type == CAddr)
if (c->sym.type == SThr) {
if (c->sym.type != SGlo) {
loadcon(c, T6, Kl, f);
*pr = TMP(T6);
}
@ -387,7 +398,7 @@ emitins(Ins *i, Fn *fn, FILE *f)
case RCon:
con = &fn->con[i->arg[0].val];
if (con->type != CAddr
|| con->sym.type != SGlo
|| (con->sym.type & SThr)
|| con->bits.i)
goto Invalid;
fprintf(f, "\tcall %s\n", str(con->sym.id));

View File

@ -29,7 +29,7 @@ char *tok[] = {
"function", "type", "data", "section", "align", "dbgfile",
"blit", "l", "w", "sh", "uh", "h", "sb", "ub", "b",
"d", "s", "z", "loadw", "loadl", "loads", "loadd",
"alloc1", "alloc2", "thread", "common",
"alloc1", "alloc2", "thread", "extern", "common",
};
enum {