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Exports load command #3149

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Merged
merged 2 commits into from
Aug 10, 2021
Merged

Exports load command #3149

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54c91c3
[MachO] Introduce chained fixups related load commands.
Aug 6, 2021
ceab8f1
Use LC_DYLD_EXPORTS_TRIE to locate the dyld trie structure if present
jimingham Aug 6, 2021
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19 changes: 18 additions & 1 deletion lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2231,6 +2231,7 @@ size_t ObjectFileMachO::ParseSymtab() {

llvm::MachO::symtab_command symtab_load_command = {0, 0, 0, 0, 0, 0};
llvm::MachO::linkedit_data_command function_starts_load_command = {0, 0, 0, 0};
llvm::MachO::linkedit_data_command exports_trie_load_command = {0, 0, 0, 0};
llvm::MachO::dyld_info_command dyld_info = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
// The data element of type bool indicates that this entry is thumb
// code.
Expand Down Expand Up @@ -2308,11 +2309,19 @@ size_t ObjectFileMachO::ParseSymtab() {
}
} break;

case LC_DYLD_EXPORTS_TRIE:
exports_trie_load_command.cmd = lc.cmd;
exports_trie_load_command.cmdsize = lc.cmdsize;
if (m_data.GetU32(&offset, &exports_trie_load_command.dataoff, 2) ==
nullptr) // fill in offset and size fields
memset(&exports_trie_load_command, 0,
sizeof(exports_trie_load_command));
break;
case LC_FUNCTION_STARTS:
function_starts_load_command.cmd = lc.cmd;
function_starts_load_command.cmdsize = lc.cmdsize;
if (m_data.GetU32(&offset, &function_starts_load_command.dataoff, 2) ==
nullptr) // fill in symoff, nsyms, stroff, strsize fields
nullptr) // fill in data offset and size fields
memset(&function_starts_load_command, 0,
sizeof(function_starts_load_command));
break;
Expand Down Expand Up @@ -2456,16 +2465,24 @@ size_t ObjectFileMachO::ParseSymtab() {
dyld_info.export_off += linkedit_slide;
m_dysymtab.indirectsymoff += linkedit_slide;
function_starts_load_command.dataoff += linkedit_slide;
exports_trie_load_command.dataoff += linkedit_slide;
}

nlist_data.SetData(m_data, symtab_load_command.symoff,
nlist_data_byte_size);
strtab_data.SetData(m_data, symtab_load_command.stroff,
strtab_data_byte_size);

// We shouldn't have exports data from both the LC_DYLD_INFO command
// AND the LC_DYLD_EXPORTS_TRIE command in the same binary:
lldbassert(!((dyld_info.export_size > 0)
&& (exports_trie_load_command.datasize > 0)));
if (dyld_info.export_size > 0) {
dyld_trie_data.SetData(m_data, dyld_info.export_off,
dyld_info.export_size);
} else if (exports_trie_load_command.datasize > 0) {
dyld_trie_data.SetData(m_data, exports_trie_load_command.dataoff,
exports_trie_load_command.datasize);
}

if (m_dysymtab.nindirectsyms != 0) {
Expand Down
2 changes: 2 additions & 0 deletions llvm/include/llvm/BinaryFormat/MachO.def
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Expand Up @@ -74,6 +74,8 @@ HANDLE_LOAD_COMMAND(LC_VERSION_MIN_TVOS, 0x0000002Fu, version_min_command)
HANDLE_LOAD_COMMAND(LC_VERSION_MIN_WATCHOS, 0x00000030u, version_min_command)
HANDLE_LOAD_COMMAND(LC_NOTE, 0x00000031u, note_command)
HANDLE_LOAD_COMMAND(LC_BUILD_VERSION, 0x00000032u, build_version_command)
HANDLE_LOAD_COMMAND(LC_DYLD_EXPORTS_TRIE, 0x80000033u, linkedit_data_command)
HANDLE_LOAD_COMMAND(LC_DYLD_CHAINED_FIXUPS, 0x80000034u, linkedit_data_command)

#endif

Expand Down