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

View File

@ -195,7 +195,7 @@ emitcon(Con *con, E *e)
case CAddr: case CAddr:
l = str(con->sym.id); l = str(con->sym.id);
p = l[0] == '"' ? "" : T.assym; p = l[0] == '"' ? "" : T.assym;
if (con->sym.type == SThr) { if (con->sym.type & SThr) {
if (T.apple) if (T.apple)
fprintf(e->f, "%s%s@TLVP", p, l); fprintf(e->f, "%s%s@TLVP", p, l);
else else
@ -551,14 +551,48 @@ emitins(Ins i, E *e)
regtoa(i.to.val, SLong)); regtoa(i.to.val, SLong));
break; 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; goto Table;
case Ocall: case Ocall:
/* calls simply have a weird syntax in AT&T /* calls simply have a weird syntax in AT&T
* assembly... */ * assembly... */
switch (rtype(i.arg[0])) { switch (rtype(i.arg[0])) {
case RCon: case RCon:
con = &e->fn->con[i.arg[0].val];
fprintf(e->f, "\tcallq "); 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"); fprintf(e->f, "\n");
break; break;
case RTmp: case RTmp:

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@ -120,8 +120,34 @@ fixarg(Ref *r, int k, Ins *i, Fn *fn)
r1 = newtmp("isel", Kl, fn); r1 = newtmp("isel", Kl, fn);
emit(Oaddr, Kl, r1, SLOT(s), R); 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) 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); r1 = newtmp("isel", Kl, fn);
if (c->bits.i) { if (c->bits.i) {
r2 = newtmp("isel", Kl, fn); 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_hi12:SO, lsl #12\n"
"\tadd\tR, R, #:tprel_lo12_nc:SO\n"; "\tadd\tR, R, #:tprel_lo12_nc:SO\n";
break; 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); l = str(c->sym.id);
@ -468,7 +479,7 @@ emitins(Ins *i, E *e)
goto Table; goto Table;
c = &e->fn->con[i->arg[0].val]; c = &e->fn->con[i->arg[0].val];
if (c->type != CAddr if (c->type != CAddr
|| c->sym.type != SGlo || (c->sym.type & SThr)
|| c->bits.i) || c->bits.i)
die("invalid call argument"); die("invalid call argument");
l = str(c->sym.id); l = str(c->sym.id);

View File

@ -180,7 +180,9 @@ by zero-extension, or by sign-extension.
DYNCONST := DYNCONST :=
CONST 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 := VAL :=
DYNCONST DYNCONST
@ -225,6 +227,16 @@ When the `thread` keyword prefixes a symbol name, the
symbol's numeric value is resolved at runtime in the symbol's numeric value is resolved at runtime in the
thread-local storage. 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 Vals are used as arguments in regular, phi, and jump
instructions within function definitions. They are instructions within function definitions. They are
either constants or function-scope temporaries. either constants or function-scope temporaries.

15
parse.c
View File

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

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@ -131,7 +131,7 @@ slot(Ref r, Fn *fn)
static void static void
emitaddr(Con *c, FILE *f) 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); fputs(str(c->sym.id), f);
if (c->bits.i) if (c->bits.i)
fprintf(f, "+%"PRIi64, c->bits.i); fprintf(f, "+%"PRIi64, c->bits.i);
@ -231,7 +231,8 @@ loadaddr(Con *c, char *rn, FILE *f)
{ {
char off[32]; char off[32];
if (c->sym.type == SThr) { switch (c->sym.type) {
case SThr:
if (c->bits.i) if (c->bits.i)
sprintf(off, "+%"PRIi64, c->bits.i); sprintf(off, "+%"PRIi64, c->bits.i);
else else
@ -242,10 +243,20 @@ loadaddr(Con *c, char *rn, FILE *f)
rn, rn, str(c->sym.id), off); rn, rn, str(c->sym.id), off);
fprintf(f, "\taddi %s, %s, %%tprel_lo(%s)%s\n", fprintf(f, "\taddi %s, %s, %%tprel_lo(%s)%s\n",
rn, rn, str(c->sym.id), off); rn, rn, str(c->sym.id), off);
} else { break;
case SExt:
fprintf(f, "\tla %s, ", rn); fprintf(f, "\tla %s, ", rn);
emitaddr(c, f); emitaddr(c, f);
fputc('\n', 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) { if (rtype(r) == RCon) {
c = &fn->con[r.val]; c = &fn->con[r.val];
if (c->type == CAddr) if (c->type == CAddr)
if (c->sym.type == SThr) { if (c->sym.type != SGlo) {
loadcon(c, T6, Kl, f); loadcon(c, T6, Kl, f);
*pr = TMP(T6); *pr = TMP(T6);
} }
@ -387,7 +398,7 @@ emitins(Ins *i, Fn *fn, FILE *f)
case RCon: case RCon:
con = &fn->con[i->arg[0].val]; con = &fn->con[i->arg[0].val];
if (con->type != CAddr if (con->type != CAddr
|| con->sym.type != SGlo || (con->sym.type & SThr)
|| con->bits.i) || con->bits.i)
goto Invalid; goto Invalid;
fprintf(f, "\tcall %s\n", str(con->sym.id)); fprintf(f, "\tcall %s\n", str(con->sym.id));

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