diff --git a/all.h b/all.h index 9e1e633..1ea5a4a 100644 --- a/all.h +++ b/all.h @@ -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; }; diff --git a/amd64/emit.c b/amd64/emit.c index 4a3bb99..e5edc90 100644 --- a/amd64/emit.c +++ b/amd64/emit.c @@ -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: diff --git a/amd64/isel.c b/amd64/isel.c index 889c647..b4769c3 100644 --- a/amd64/isel.c +++ b/amd64/isel.c @@ -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); diff --git a/arm64/emit.c b/arm64/emit.c index c339e41..18c5ceb 100644 --- a/arm64/emit.c +++ b/arm64/emit.c @@ -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); diff --git a/doc/il.txt b/doc/il.txt index 746a7d2..1f1bc29 100644 --- a/doc/il.txt +++ b/doc/il.txt @@ -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' $IDENT # Extern thread-local (initial-exec) VAL := DYNCONST @@ -225,6 +227,16 @@ When the `thread` keyword prefixes a symbol name, the symbol's numeric value is resolved at runtime in the thread-local storage. +When the `extern` keyword prefixes a symbol name, the +symbol is accessed indirectly through the Global Offset +Table (GOT). Function calls to extern symbols use the +Procedure Linkage Table (PLT). This enables PIE and +PIC code generation for symbols that are not part of +the main executable. When `extern` is combined with +`thread`, the symbol is accessed using the initial-exec +TLS model, suitable for thread-local variables defined +in shared libraries. + Vals are used as arguments in regular, phi, and jump instructions within function definitions. They are either constants or function-scope temporaries. diff --git a/parse.c b/parse.c index a063367..0ca5f1d 100644 --- a/parse.c +++ b/parse.c @@ -57,6 +57,7 @@ enum Token { Thlt, Texport, Tthread, + Textern, Tcommon, Tfunc, Ttype, @@ -116,6 +117,7 @@ static char *kwmap[Ntok] = { [Thlt] = "hlt", [Texport] = "export", [Tthread] = "thread", + [Textern] = "extern", [Tcommon] = "common", [Tfunc] = "function", [Ttype] = "type", @@ -448,11 +450,20 @@ parseref() c.bits.d = tokval.fltd; c.flt = 2; break; + case Textern: + c.sym.type = SExt; + if (peek() == Tthread) { + next(); + c.sym.type |= SThr; + } + expect(Tglo); + goto Glo; case Tthread: c.sym.type = SThr; expect(Tglo); /* fall through */ case Tglo: + Glo: c.type = CAddr; c.sym.id = intern(tokval.str); break; @@ -1255,7 +1266,9 @@ printcon(Con *c, FILE *f) case CUndef: break; case CAddr: - if (c->sym.type == SThr) + if (c->sym.type & SExt) + fprintf(f, "extern "); + if (c->sym.type & SThr) fprintf(f, "thread "); fprintf(f, "$%s", str(c->sym.id)); if (c->bits.i) diff --git a/rv64/emit.c b/rv64/emit.c index c1f29ac..53f810b 100644 --- a/rv64/emit.c +++ b/rv64/emit.c @@ -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)); diff --git a/tools/lexh.c b/tools/lexh.c index efc30fe..82f3826 100644 --- a/tools/lexh.c +++ b/tools/lexh.c @@ -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 {