llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-lldb Author: Greg Clayton (clayborg) <details> <summary>Changes</summary> llvm-dsymutil can produce mach-o files where some sections in __DWARF exceed the 4GB barrier and subsequent sections in the dSYM will be inaccessible because the mach-o section_64 structure only has a 32 bit file offset. This patch enables LLDB to load a large dSYM file by figuring out when this happens and properly adjusting the file offset of the LLDB sections. I was unable to add a test as obj2yaml and yaml2obj are broken for mach-o files and they can't convert a yaml file back into a valid mach-o object file. Any suggestions for adding a test would be appreciated. --- Full diff: https://github.com/llvm/llvm-project/pull/164471.diff 1 Files Affected: - (modified) lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp (+19-7) ``````````diff diff --git a/lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp b/lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp index 9cdb8467bfc60..6878f7331e0f5 100644 --- a/lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp +++ b/lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp @@ -1674,6 +1674,10 @@ void ObjectFileMachO::ProcessSegmentCommand( uint32_t segment_sect_idx; const lldb::user_id_t first_segment_sectID = context.NextSectionIdx + 1; + // dSYM files can create sections whose data exceeds the 4GB barrier, but + // mach-o sections only have 32 bit offsets. So keep track of when we + // overflow and fix the sections offsets as we iterate. + uint64_t section_offset_adjust = 0; const uint32_t num_u32s = load_cmd.cmd == LC_SEGMENT ? 7 : 8; for (segment_sect_idx = 0; segment_sect_idx < load_cmd.nsects; ++segment_sect_idx) { @@ -1697,6 +1701,14 @@ void ObjectFileMachO::ProcessSegmentCommand( // isn't stored in the abstracted Sections. m_mach_sections.push_back(sect64); + // Make sure we can load dSYM files whose __DWARF sections exceed the 4GB + // barrier. llvm::MachO::section_64 have only 32 bit file offsets for the + // section contents. + const uint64_t section_file_offset = sect64.offset + section_offset_adjust; + // If this section overflows a 4GB barrier, then we need to adjust any + // subsequent the section offsets. + if (is_dsym && ((uint64_t)sect64.offset + sect64.size) >= UINT32_MAX) + section_offset_adjust += 0x100000000ull; if (add_section) { ConstString section_name( sect64.sectname, strnlen(sect64.sectname, sizeof(sect64.sectname))); @@ -1736,13 +1748,13 @@ void ObjectFileMachO::ProcessSegmentCommand( } // Grow the section size as needed. - if (sect64.offset) { + if (section_file_offset) { const lldb::addr_t segment_min_file_offset = segment->GetFileOffset(); const lldb::addr_t segment_max_file_offset = segment_min_file_offset + segment->GetFileSize(); - const lldb::addr_t section_min_file_offset = sect64.offset; + const lldb::addr_t section_min_file_offset = section_file_offset; const lldb::addr_t section_max_file_offset = section_min_file_offset + sect64.size; const lldb::addr_t new_file_offset = @@ -1770,9 +1782,9 @@ void ObjectFileMachO::ProcessSegmentCommand( sect64.addr, // File VM address == addresses as they are // found in the object file sect64.size, // VM size in bytes of this section - sect64.offset, // Offset to the data for this section in + section_file_offset, // Offset to the data for this section in // the file - sect64.offset ? sect64.size : 0, // Size in bytes of + section_file_offset ? sect64.size : 0, // Size in bytes of // this section as // found in the file sect64.align, @@ -1792,14 +1804,14 @@ void ObjectFileMachO::ProcessSegmentCommand( SectionSP section_sp(new Section( segment_sp, module_sp, this, ++context.NextSectionIdx, section_name, sect_type, sect64.addr - segment_sp->GetFileAddress(), sect64.size, - sect64.offset, sect64.offset == 0 ? 0 : sect64.size, sect64.align, - sect64.flags)); + section_file_offset, section_file_offset == 0 ? 0 : sect64.size, + sect64.align, sect64.flags)); // Set the section to be encrypted to match the segment bool section_is_encrypted = false; if (!segment_is_encrypted && load_cmd.filesize != 0) section_is_encrypted = context.EncryptedRanges.FindEntryThatContains( - sect64.offset) != nullptr; + section_file_offset) != nullptr; section_sp->SetIsEncrypted(segment_is_encrypted || section_is_encrypted); section_sp->SetPermissions(segment_permissions); `````````` </details> https://github.com/llvm/llvm-project/pull/164471 _______________________________________________ lldb-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
