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[!14784] Improve mach-o relocation information #69

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[!14784] Improve mach-o relocation information #69

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53 changes: 36 additions & 17 deletions rts/linker/MachO.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand Down Expand Up @@ -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;
Expand All @@ -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;
Expand All @@ -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;
}
Expand All @@ -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;
Expand All @@ -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)) {
Expand Down Expand Up @@ -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:
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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:
Expand All @@ -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;
Expand All @@ -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;
Expand Down