Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC Commits: 1537784b by Moritz Angermann at 2025-09-10T10:47:13-04:00 Improve mach-o relocation information This change adds more information about the symbol and addresses we try to relocate in the linker. This significantly helps when deubbging relocation issues reported by users. - - - - - 1 changed file: - rts/linker/MachO.c Changes: ===================================== rts/linker/MachO.c ===================================== @@ -64,7 +64,7 @@ static bool fitsBits(size_t bits, int64_t value); static int64_t decodeAddend(ObjectCode * oc, Section * section, MachORelocationInfo * ri); static void encodeAddend(ObjectCode * oc, Section * section, - MachORelocationInfo * ri, int64_t addend); + MachORelocationInfo * ri, int64_t addend, MachOSymbol * symbol); /* Global Offset Table logic */ static bool isGotLoad(MachORelocationInfo * ri); @@ -361,15 +361,21 @@ fitsBits(size_t bits, int64_t value) { static void encodeAddend(ObjectCode * oc, Section * section, - MachORelocationInfo * ri, int64_t addend) { + MachORelocationInfo * ri, int64_t addend, MachOSymbol * symbol) { uint32_t * p = (uint32_t*)((uint8_t*)section->start + ri->r_address); checkProddableBlock(&oc->proddables, (void*)p, 1 << ri->r_length); + const char *symbol_name = symbol && symbol->name ? (char*)symbol->name : "<unknown>"; + const char *file_name = oc->fileName ? (char*)oc->fileName : "<unknown>"; + switch (ri->r_type) { case ARM64_RELOC_UNSIGNED: { - if(!fitsBits(8 << ri->r_length, addend)) - barf("Relocation out of range for UNSIGNED"); + if(!fitsBits(8 << ri->r_length, addend)) { + const char *library_info = OC_INFORMATIVE_FILENAME(oc); + barf("Relocation out of range for UNSIGNED in %s: symbol '%s', addend 0x%llx, address 0x%llx, library: %s", + file_name, symbol_name, (long long)addend, (long long)ri->r_address, library_info ? (char*)library_info : "<unknown>"); + } switch (ri->r_length) { case 0: *(uint8_t*)p = (uint8_t)addend; break; case 1: *(uint16_t*)p = (uint16_t)addend; break; @@ -382,8 +388,11 @@ encodeAddend(ObjectCode * oc, Section * section, return; } case ARM64_RELOC_SUBTRACTOR: { - if(!fitsBits(8 << ri->r_length, addend)) - barf("Relocation out of range for SUBTRACTOR"); + if(!fitsBits(8 << ri->r_length, addend)) { + const char *library_info = OC_INFORMATIVE_FILENAME(oc); + barf("Relocation out of range for SUBTRACTOR in %s: symbol '%s', addend 0x%llx, address 0x%llx, library: %s", + file_name, symbol_name, (long long)addend, (long long)ri->r_address, library_info ? (char*)library_info : "<unknown>"); + } switch (ri->r_length) { case 0: *(uint8_t*)p = (uint8_t)addend; break; case 1: *(uint16_t*)p = (uint16_t)addend; break; @@ -400,8 +409,11 @@ encodeAddend(ObjectCode * oc, Section * section, * do not need the last two bits of the value. If the value >> 2 * still exceeds 26bits, we won't be able to reach it. */ - if(!fitsBits(26, addend >> 2)) - barf("Relocation target for BRACH26 out of range."); + if(!fitsBits(26, addend >> 2)) { + const char *library_info = OC_INFORMATIVE_FILENAME(oc); + barf("Relocation target for BRANCH26 out of range in %s: symbol '%s', addend 0x%llx (0x%llx >> 2), address 0x%llx, library: %s", + file_name, symbol_name, (long long)addend, (long long)(addend >> 2), (long long)ri->r_address, library_info ? (char*)library_info : "<unknown>"); + } *p = (*p & 0xFC000000) | ((uint32_t)(addend >> 2) & 0x03FFFFFF); return; } @@ -412,8 +424,12 @@ encodeAddend(ObjectCode * oc, Section * section, * with the PAGEOFF12 relocation allows to address a relative range * of +-4GB. */ - if(!fitsBits(21, addend >> 12)) - barf("Relocation target for PAGE21 out of range."); + if(!fitsBits(21, addend >> 12)) { + const char *reloc_type = (ri->r_type == ARM64_RELOC_PAGE21) ? "PAGE21" : "GOT_LOAD_PAGE21"; + const char *library_info = OC_INFORMATIVE_FILENAME(oc); + barf("Relocation target for %s out of range in %s: symbol '%s', addend 0x%llx (0x%llx >> 12), address 0x%llx, library: %s", + reloc_type, file_name, symbol_name, (long long)addend, (long long)(addend >> 12), (long long)ri->r_address, library_info ? (char*)library_info : "<unknown>"); + } *p = (*p & 0x9F00001F) | (uint32_t)((addend << 17) & 0x60000000) | (uint32_t)((addend >> 9) & 0x00FFFFE0); return; @@ -423,8 +439,11 @@ encodeAddend(ObjectCode * oc, Section * section, /* Store an offset into a page (4k). Depending on the instruction * the bits are stored at slightly different positions. */ - if(!fitsBits(12, addend)) - barf("Relocation target for PAGEOFF12 out or range."); + if(!fitsBits(12, addend)) { + const char *library_info = OC_INFORMATIVE_FILENAME(oc); + barf("Relocation target for PAGEOFF12 out of range in %s: symbol '%s', addend 0x%llx, address 0x%llx, library: %s", + file_name, symbol_name, (long long)addend, (long long)ri->r_address, library_info ? (char*)library_info : "<unknown>"); + } int shift = 0; if(isLoadStore(p)) { @@ -589,7 +608,7 @@ relocateSectionAarch64(ObjectCode * oc, Section * section) MachOSymbol* symbol = &oc->info->macho_symbols[ri->r_symbolnum]; int64_t addend = decodeAddend(oc, section, ri); uint64_t value = symbol_value(oc, symbol); - encodeAddend(oc, section, ri, value + addend); + encodeAddend(oc, section, ri, value + addend, symbol); break; } case ARM64_RELOC_SUBTRACTOR: @@ -623,7 +642,7 @@ relocateSectionAarch64(ObjectCode * oc, Section * section) // combine with addend and store int64_t addend = decodeAddend(oc, section, ri); - encodeAddend(oc, section, ri, addend - sub_value + add_value); + encodeAddend(oc, section, ri, addend - sub_value + add_value, symbol1); // skip next relocation: we've already handled it i += 1; @@ -664,7 +683,7 @@ relocateSectionAarch64(ObjectCode * oc, Section * section) } } } - encodeAddend(oc, section, ri, value - pc + addend); + encodeAddend(oc, section, ri, value - pc + addend, symbol); break; } case ARM64_RELOC_PAGE21: @@ -676,7 +695,7 @@ relocateSectionAarch64(ObjectCode * oc, Section * section) uint64_t pc = (uint64_t)section->start + ri->r_address; uint64_t value = (uint64_t)(isGotLoad(ri) ? symbol->got_addr : symbol->addr); ASSERT(!isGotLoad(ri) || (symbol->got_addr != 0)); - encodeAddend(oc, section, ri, ((value + addend + explicit_addend) & (-4096)) - (pc & (-4096))); + encodeAddend(oc, section, ri, ((value + addend + explicit_addend) & (-4096)) - (pc & (-4096)), symbol); // reset, just in case. explicit_addend = 0; @@ -690,7 +709,7 @@ relocateSectionAarch64(ObjectCode * oc, Section * section) barf("explicit_addend and addend can't be set at the same time."); uint64_t value = (uint64_t)(isGotLoad(ri) ? symbol->got_addr : symbol->addr); ASSERT(!isGotLoad(ri) || (symbol->got_addr != 0)); - encodeAddend(oc, section, ri, 0xFFF & (value + addend + explicit_addend)); + encodeAddend(oc, section, ri, 0xFFF & (value + addend + explicit_addend), symbol); // reset, just in case. explicit_addend = 0; View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/1537784bd4928f5ae60504e8ef467279... -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/1537784bd4928f5ae60504e8ef467279... 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