On ARM targets, the jump to ld.so resolution routine is done in PLT0 by loading the offset to the GOT found in PLT+16 and from there loading the address in GOT+8 and jumping to it. Currently tcc starts the first regular PLT entry at PLT+16 which thus does not contain the offset to the GOT. This commit fixes that. Note that calls via PLT still worked nonetheless because of some missing dynamic tag which makes ld.so behaves as if RTLD_BIND_NOW was specified in the environment for all executable created by tcc.
Unified · Split
| @@ -1421,11 +1421,12 @@ static unsigned long put_got_entry(TCCState *s1, · 1420 unmodified lines | ||
| 1421 | 1421 | /* empty PLT: create PLT0 entry that push address of call site and |
| 1422 | 1422 | jump to ld.so resolution routine (GOT + 8) */ |
| 1423 | 1423 | if (plt->data_offset == 0) { |
| 1424 | − p = section_ptr_add(plt, 16); | |
| 1424 | + p = section_ptr_add(plt, 20); | |
| 1425 | 1425 | write32le(p, 0xe52de004); /* push {lr} */ |
| 1426 | − write32le(p+4, 0xe59fe010); /* ldr lr, [pc, #16] */ | |
| 1426 | + write32le(p+4, 0xe59fe004); /* ldr lr, [pc, #4] */ | |
| 1427 | 1427 | write32le(p+8, 0xe08fe00e); /* add lr, pc, lr */ |
| 1428 | 1428 | write32le(p+12, 0xe5bef008); /* ldr pc, [lr, #8]! */ |
| 1429 | + /* p+16 is set in relocate_plt */ | |
| 1429 | 1430 | } |
| 1430 | 1431 | |
| 1431 | 1432 | symattr->plt_offset = plt->data_offset; |
| @@ -2151,7 +2152,8 @@ ST_FUNC void relocate_plt(TCCState *s1) · 719 unmodified lines | ||
| 2151 | 2152 | } |
| 2152 | 2153 | #elif defined(TCC_TARGET_ARM) |
| 2153 | 2154 | int x = s1->got->sh_addr - s1->plt->sh_addr - 12; |
| 2154 | − p += 16; | |
| 2155 | + write32le(s1->plt->data + 16, x - 16); | |
| 2156 | + p += 20; | |
| 2155 | 2157 | while (p < p_end) { |
| 2156 | 2158 | if (read32le(p) == 0x46c04778) /* PLT Thumb stub present */ |
| 2157 | 2159 | p += 4; |