linkers don't treat relocations using symindex 0 (undefined) very well, it can't be misused as indicator for an absolute number. Just don't bother with special casing this, rather emit an indirect call/jump right away. ARM64 needs the same (and didn't handle calls via constant absolute func pointers before). The testcase as is doesn't fail without the patch, it actually needs separate compilation (to -fPIC .o file, then to shared lib) to fail.
Unified · Split
| @@ -580,8 +580,8 @@ ST_FUNC void store(int r, SValue *sv) · 579 unmodified lines | ||
| 580 | 580 | |
| 581 | 581 | static void arm64_gen_bl_or_b(int b) |
| 582 | 582 | { |
| 583 | − if ((vtop->r & (VT_VALMASK | VT_LVAL)) == VT_CONST) { | |
| 584 | − assert(!b && (vtop->r & VT_SYM)); | |
| 583 | + if ((vtop->r & (VT_VALMASK | VT_LVAL)) == VT_CONST && (vtop->r & VT_SYM)) { | |
| 584 | + assert(!b); | |
| 585 | 585 | greloca(cur_text_section, vtop->sym, ind, R_AARCH64_CALL26, 0); |
| 586 | 586 | o(0x94000000); // bl . |
| 587 | 587 | } |
| @@ -15,6 +15,11 @@ void qfunc() · 14 unmodified lines | ||
| 15 | 15 | printf("qfunc()\n"); |
| 16 | 16 | } |
| 17 | 17 | |
| 18 | +void zfunc() | |
| 19 | +{ | |
| 20 | + ((void (*)(void))0) (); | |
| 21 | +} | |
| 22 | + | |
| 18 | 23 | int main() |
| 19 | 24 | { |
| 20 | 25 | printf("%d\n", myfunc(3)); |
| @@ -623,20 +623,13 @@ static void gcall_or_jmp(int is_jmp) · 622 unmodified lines | ||
| 623 | 623 | { |
| 624 | 624 | int r; |
| 625 | 625 | if ((vtop->r & (VT_VALMASK | VT_LVAL)) == VT_CONST && |
| 626 | − ((vtop->r & VT_SYM) || (vtop->c.i-4) == (int)(vtop->c.i-4))) { | |
| 627 | − /* constant case */ | |
| 628 | − if (vtop->r & VT_SYM) { | |
| 629 | − /* relocation case */ | |
| 626 | + ((vtop->r & VT_SYM) && (vtop->c.i-4) == (int)(vtop->c.i-4))) { | |
| 627 | + /* constant symbolic case -> simple relocation */ | |
| 630 | 628 | #ifdef TCC_TARGET_PE |
| 631 | − greloca(cur_text_section, vtop->sym, ind + 1, R_X86_64_PC32, (int)(vtop->c.i-4)); | |
| 629 | + greloca(cur_text_section, vtop->sym, ind + 1, R_X86_64_PC32, (int)(vtop->c.i-4)); | |
| 632 | 630 | #else |
| 633 | − greloca(cur_text_section, vtop->sym, ind + 1, R_X86_64_PLT32, (int)(vtop->c.i-4)); | |
| 631 | + greloca(cur_text_section, vtop->sym, ind + 1, R_X86_64_PLT32, (int)(vtop->c.i-4)); | |
| 634 | 632 | #endif |
| 635 | − } else { | |
| 636 | − /* put an empty PC32 relocation */ | |
| 637 | − put_elf_reloca(symtab_section, cur_text_section, | |
| 638 | − ind + 1, R_X86_64_PC32, 0, (int)(vtop->c.i-4)); | |
| 639 | − } | |
| 640 | 633 | oad(0xe8 + is_jmp, 0); /* call/jmp im */ |
| 641 | 634 | } else { |
| 642 | 635 | /* otherwise, indirect call */ |