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--- dyld/dyld-1231.3/mach_o/CompactUnwind.cpp
+++ dyld/dyld-1330/mach_o/CompactUnwind.cpp
@@ -348,6 +348,9 @@
case 1:
permunreg[0] = permutation;
break;
+ default:
+ strlcat(strBuf, "unsupported registers saved", 128);
+ return;
}
// renumber registers back to standard numbers
int registers[6];
@@ -434,7 +437,10 @@
}
const uint32_t firstLevelIndex = low;
const uint32_t firstLevelFunctionOffset = firstLevelTable[firstLevelIndex].functionOffset;
- const uint32_t firstLevelEndFunctionOffset = firstLevelTable[firstLevelIndex+1].functionOffset;
+ const uint32_t firstLevelEndFunctionOffset =
+ (firstLevelIndex+1) >= _unwindTable->indexCount
+ ? firstLevelFunctionOffset + 1
+ : firstLevelTable[firstLevelIndex+1].functionOffset;
const void* secondLevelAddr = (uint8_t*)_unwindTable + firstLevelTable[firstLevelIndex].secondLevelPagesSectionOffset;
if ( targetFunctionOffset > firstLevelEndFunctionOffset )
@@ -454,7 +460,6 @@
if ( entries[mid].functionOffset <= targetFunctionOffset ) {
if ( (mid == last) || (entries[mid+1].functionOffset > targetFunctionOffset) ) {
// next is past target address, so we found it
- low = mid;
result.funcOffset = entries[mid].functionOffset;
result.encoding = entries[mid].encoding;
result.lsdaOffset = 0;
@@ -483,7 +488,6 @@
uint32_t mid = (low + high)/2;
if ( UNWIND_INFO_COMPRESSED_ENTRY_FUNC_OFFSET(entries[mid]) <= targetOffset ) {
if ( (mid == last) || (UNWIND_INFO_COMPRESSED_ENTRY_FUNC_OFFSET(entries[mid+1]) > targetOffset) ) {
- low = mid;
result.funcOffset = UNWIND_INFO_COMPRESSED_ENTRY_FUNC_OFFSET(entries[mid]) + firstLevelFunctionOffset;
uint8_t encodingIndex = UNWIND_INFO_COMPRESSED_ENTRY_ENCODING_INDEX(entries[mid]);
if ( encodingIndex < _unwindTable->commonEncodingsArrayCount )
@@ -546,372 +550,6 @@
}
-#if BUILDING_MACHO_WRITER
-
-bool CompactUnwind::encodingMeansUseDwarf(Architecture arch, uint32_t encoding)
-{
- if ( arch.usesArm64Instructions() )
- return ((encoding & UNWIND_ARM64_MODE_MASK) == UNWIND_ARM64_MODE_DWARF);
- else if ( arch.usesx86_64Instructions() )
- return ((encoding & UNWIND_X86_64_MODE_MASK) == UNWIND_X86_64_MODE_DWARF);
- assert(0 && "arch not supported for compact unwind");
-}
-
-bool CompactUnwind::encodingCannotBeMerged(Architecture arch, uint32_t encoding)
-{
- if ( arch.usesx86_64Instructions() )
- return ((encoding & UNWIND_X86_64_MODE_MASK) == UNWIND_X86_64_MODE_STACK_IND);
- return false;
-}
-
-// there are two bits in compact unwind that encode which personality function is used
-// this function keeps track of which personality functions are used and when their 2-bit index is
-void CompactUnwind::updatePersonalityForEntry(WriterUnwindInfo& entry, std::vector<UniquePersonality>& personalities)
-{
- if ( (entry.personalityHandle != nullptr) || (entry.personalityOffset != 0) ) {
- std::optional<uint32_t> index;
- for ( const UniquePersonality& personality : personalities ) {
- if ( personality.handle == entry.personalityHandle ) {
- index = &personality - personalities.data();
- break;
- }
- else if ( (personality.handle == 0) && (entry.personalityHandle == 0)
- && (personality.offset != 0) && (personality.offset == entry.personalityOffset) ) {
- index = &personality - personalities.data();
- break;
- }
- }
- if ( !index.has_value() ) {
- index = personalities.size();
- personalities.push_back({ entry.personalityOffset, entry.personalityHandle });
- }
- // update entry with personality index
- entry.encoding |= ((index.value()+ 1) << (__builtin_ctz(UNWIND_PERSONALITY_MASK)) );
- }
-}
-
-void CompactUnwind::compressDuplicates(Architecture arch, std::vector<WriterUnwindInfo>& entries, uint32_t& lsdaCount,
- CommonEncodingsMap& commonEncodings, std::vector<UniquePersonality>& personalities)
-{
- lsdaCount = 0;
- // build a vector removing entries where next function has same encoding
- WriterUnwindInfo last = { ~0U, ~0U, ~0U, ~0U, nullptr, nullptr, nullptr };
- // encoding frequency to build common encodings
- size_t inEntriesSize = entries.size();
- std::unordered_map<compact_unwind_encoding_t, unsigned int> encodingsUsed;
- std::erase_if(entries, [&](WriterUnwindInfo& entry) {
- this->updatePersonalityForEntry(entry, personalities);
- bool newNeedsDwarf = encodingMeansUseDwarf(arch, entry.encoding);
- bool cannotBeMerged = encodingCannotBeMerged(arch, entry.encoding);
- bool duplicate = true;
- // remove entries which have same encoding and personalityPointer as last one
- if ( newNeedsDwarf || (entry.encoding != last.encoding) || (entry.personalityHandle != last.personalityHandle)
- || cannotBeMerged || (entry.lsdaHandle != nullptr) ) {
- duplicate = false;
-
- // never put dwarf into common table
- if ( !newNeedsDwarf )
- encodingsUsed[entry.encoding] += 1;
- }
- if ( entry.encoding & UNWIND_HAS_LSDA ) {
- ++lsdaCount;
- assert(entry.lsdaHandle != nullptr);
- }
- last = entry;
- return duplicate;
- });
-
- using EncodingsAndUsage = std::pair<compact_unwind_encoding_t, unsigned int>;
- // put encodings into a vector and sort them descending by frequency and
- // ascending by the encoding value
- // there's a limited number of unique encodings but many entries so it's
- // faster to use an unordered map for encodings and sort it here
- std::vector<EncodingsAndUsage> encodingsByUsage;
- encodingsByUsage.resize(encodingsUsed.size());
- std::copy(encodingsUsed.begin(), encodingsUsed.end(), encodingsByUsage.begin());
- std::sort(encodingsByUsage.begin(), encodingsByUsage.end(),
- [](const EncodingsAndUsage& l, const EncodingsAndUsage& r) {
- if ( l.second != r.second )
- return l.second > r.second;
- /* sort by encoding time for same number of usages for deterministic output */
- return l.first < r.first;
- });
- // put the most common encodings into the common table, but at most 127 of them
- uint32_t maxNumCommonEncodings = std::min((uint32_t)encodingsByUsage.size(), 127u);
- for ( uint32_t i = 0; i < maxNumCommonEncodings; ++i ) {
- if ( encodingsByUsage[i].second <= 1 )
- break;
- commonEncodings[encodingsByUsage[i].first] = i;
- }
- if (_verbose) fprintf(stderr, "compressDuplicates() entries.size()=%lu, uniqueEntries.size()=%lu, lsdaCount=%u\n",
- inEntriesSize, entries.size(), lsdaCount);
- if (_verbose) fprintf(stderr, "compressDuplicates() %lu common encodings found\n", commonEncodings.size());
-}
-
-uint8_t CompactUnwind::encodingIndex(uint32_t encoding, const CommonEncodingsMap& commonEncodings, const CommonEncodingsMap& pageSpecificEncodings)
-{
- const auto& pos = commonEncodings.find(encoding);
- if ( pos != commonEncodings.end() )
- return pos->second;
- else
- return pageSpecificEncodings.at(encoding);
-}
-
-void CompactUnwind::makeRegularSecondLevelPage(const std::vector<WriterUnwindInfo>& uniqueInfos, uint32_t pageSize,
- size_t& curInfosIndex, uint8_t*& pageStart, unwind_info_section_header_lsda_index_entry*& lsdaContent)
-{
- const size_t maxEntriesPerPage = (pageSize - sizeof(unwind_info_regular_second_level_page_header))/sizeof(unwind_info_regular_second_level_entry);
- const size_t entriesToAdd = std::min(maxEntriesPerPage, uniqueInfos.size() - curInfosIndex);
-
- unwind_info_regular_second_level_page_header* pageHeader = (unwind_info_regular_second_level_page_header*)pageStart;
- pageHeader->kind = UNWIND_SECOND_LEVEL_REGULAR;
- pageHeader->entryPageOffset = sizeof(unwind_info_regular_second_level_page_header);
- pageHeader->entryCount = entriesToAdd;
-
- unwind_info_regular_second_level_entry* entryArray = (unwind_info_regular_second_level_entry*)((uint8_t*)pageHeader + pageHeader->entryPageOffset);
- for (uint32_t i=0; i < entriesToAdd; ++i) {
- const WriterUnwindInfo& info = uniqueInfos[curInfosIndex + i];
- entryArray[i].functionOffset = info.funcOffset;
- entryArray[i].encoding = info.encoding;
- uint64_t entrySectionOffset = (uint8_t*)&entryArray[i].functionOffset - (uint8_t*)&_bytes[0];
- this->_imageOffsetFixups.push_back({ info.funcHandle, (uint32_t)entrySectionOffset, false });
- if ( info.encoding & UNWIND_HAS_LSDA ) {
- lsdaContent->functionOffset = info.funcOffset;
- lsdaContent->lsdaOffset = info.lsdaOffset;
- assert(info.lsdaHandle != nullptr);
-
- uint64_t sectionOffset = (uint8_t*)&lsdaContent->functionOffset - (uint8_t*)&_bytes[0];
- this->_imageOffsetFixups.push_back({ info.funcHandle, (uint32_t)sectionOffset, false });
-
- sectionOffset = (uint8_t*)&lsdaContent->lsdaOffset - (uint8_t*)&_bytes[0];
- this->_imageOffsetFixups.push_back({ info.lsdaHandle, (uint32_t)sectionOffset, false });
-
- ++lsdaContent;
- }
- }
-
- // update what has been processed
- curInfosIndex += entriesToAdd;
- pageStart += (pageHeader->entryPageOffset + pageHeader->entryCount *sizeof(unwind_info_regular_second_level_entry));
-}
-
-void CompactUnwind::makeCompressedSecondLevelPage(const std::vector<WriterUnwindInfo>& uniqueInfos, const CommonEncodingsMap& commonEncodings,
- uint32_t pageSize, size_t& curInfosIndex, uint8_t*& pageStart, unwind_info_section_header_lsda_index_entry*& lsdaContent)
-{
- // first pass calculates how many compressed entries we could fit in this sized page
- // keep adding entries to page until:
- // 1) encoding table plus entry table plus header exceed page size
- // 2) the file offset delta from the first to last function > 24 bits
- // 3) custom encoding index reaches 255
- // 4) run out of uniqueInfos to encode
- CommonEncodingsMap pageSpecificEncodings;
- uint32_t space = pageSize - sizeof(unwind_info_compressed_second_level_page_header);
- uint32_t entryCount = 0;
- while ( curInfosIndex + entryCount < uniqueInfos.size() // 4) run out of uniqueInfos to encode
- && space >= sizeof(uint32_t) ) { // 1) enough room to encode a compressed entry
- const WriterUnwindInfo& info = uniqueInfos[curInfosIndex + entryCount];
- if ( commonEncodings.find(info.encoding) == commonEncodings.end() ) {
- if ( pageSpecificEncodings.find(info.encoding) == pageSpecificEncodings.end() ) {
- // 1) enough room for the new encoding and the entry, no point adding the encoding
- // only if there won't be place for the entry
- if ( space < (sizeof(uint32_t) * 2) )
- break;
-
- // need to add page specific encoding
- uint32_t nextEncodingIndex = (uint32_t)(commonEncodings.size() + pageSpecificEncodings.size());
- if ( nextEncodingIndex <= 255 ) {
- pageSpecificEncodings[info.encoding] = nextEncodingIndex;
- space -= sizeof(uint32_t);
- } else {
- break; // 3) custom encoding index reaches 255
- }
- }
- }
- // compute function offset
- assert(info.funcOffset >= uniqueInfos[curInfosIndex].funcOffset);
- uint32_t funcOffsetWithInPage = info.funcOffset - uniqueInfos[curInfosIndex].funcOffset;
- if ( funcOffsetWithInPage > 0x00FF0000 ) {
- // don't use 0x00FFFFFF because addresses may vary after atoms are laid out again
- break; // 2) the file offset delta from the first to last function > 24 bits
- }
- ++entryCount;
- space -= sizeof(uint32_t);
- }
-
- // fallback to regular encoding when eligible compressed entries don't use all the available page space,
- // this isn't the last page and the number of the eligible entries is smaller
- // than the number of regular entries that can be encoded in this page
- if ( space >= minPageSize && (curInfosIndex + entryCount) < uniqueInfos.size() ) {
- const size_t maxEntriesPerPage = (pageSize - sizeof(unwind_info_regular_second_level_page_header))/sizeof(unwind_info_regular_second_level_entry);
- if ( entryCount < maxEntriesPerPage ) {
- makeRegularSecondLevelPage(uniqueInfos, pageSize, curInfosIndex, pageStart, lsdaContent);
- return;
- }
- }
-
- // second pass fills in page
- unwind_info_compressed_second_level_page_header* pageHeader = (unwind_info_compressed_second_level_page_header*)pageStart;
- pageHeader->kind = UNWIND_SECOND_LEVEL_COMPRESSED;
- pageHeader->entryPageOffset = sizeof(unwind_info_compressed_second_level_page_header);
- pageHeader->entryCount = entryCount;
- pageHeader->encodingsPageOffset = pageHeader->entryPageOffset + entryCount*sizeof(uint32_t);
- pageHeader->encodingsCount = pageSpecificEncodings.size();
- uint32_t* const entriesArray = (uint32_t*)((uint8_t*)pageHeader + pageHeader->entryPageOffset);
- uint32_t firstFuncOffset = uniqueInfos[curInfosIndex].funcOffset;
- const void* firstFuncHandle = uniqueInfos[curInfosIndex].funcHandle;
- for (uint32_t i=0; i < entryCount; ++i) {
- const WriterUnwindInfo& info = uniqueInfos[curInfosIndex + i];
- uint32_t offset = info.funcOffset - firstFuncOffset;
- uint8_t eIndex = encodingIndex(info.encoding, commonEncodings, pageSpecificEncodings);
- entriesArray[i] = (offset & 0x00FFFFFF) | (eIndex << 24);
- uint64_t sectionOffset = (uint8_t*)&entriesArray[i] - (uint8_t*)&_bytes[0];
- this->_diff24Fixups.push_back({ info.funcHandle, firstFuncHandle, (uint32_t)sectionOffset });
-
- if ( info.encoding & UNWIND_HAS_LSDA ) {
- lsdaContent->functionOffset = info.funcOffset;
- lsdaContent->lsdaOffset = info.lsdaOffset;
- assert(info.lsdaHandle != nullptr);
-
- sectionOffset = (uint8_t*)&lsdaContent->functionOffset - (uint8_t*)&_bytes[0];
- this->_imageOffsetFixups.push_back({ info.funcHandle, (uint32_t)sectionOffset, false });
-
- sectionOffset = (uint8_t*)&lsdaContent->lsdaOffset - (uint8_t*)&_bytes[0];
- this->_imageOffsetFixups.push_back({ info.lsdaHandle, (uint32_t)sectionOffset, false });
-
- ++lsdaContent;
- }
- }
- uint32_t* const encodingsArray = (uint32_t*)((uint8_t*)pageHeader + pageHeader->encodingsPageOffset);
- uint32_t const commonEncodingsSize = (uint32_t)commonEncodings.size();
- for (const auto& enc : pageSpecificEncodings) {
- encodingsArray[enc.second - commonEncodingsSize] = enc.first;
- }
-
- // update what has been processed
- curInfosIndex += entryCount;
- pageStart += (pageHeader->encodingsPageOffset + pageHeader->encodingsCount *sizeof(uint32_t));
-}
-
-
-//
-// FIXME CompactUnwind needs two modes: fast and optimized.
-// Fast uses regular pages every and is easy to size and layout
-// Optimize tries to make the table as small as possible, but that means the size estimation will be expensive
-//
-size_t CompactUnwind::estimateCompactUnwindTableSize(std::span<const WriterUnwindInfo> unwindInfos)
-{
- std::unordered_set<uint32_t> uniqueEncodings;
- unsigned lsdaCount = 0;
- for (const WriterUnwindInfo& entry : unwindInfos) {
- uniqueEncodings.insert(entry.encoding);
- if ( entry.encoding & UNWIND_HAS_LSDA )
- ++lsdaCount;
- }
- //fprintf(stderr, "ext: unwindInfos.size=%lu uniqueEncodings.size=%lu\n", unwindInfos.size(), uniqueEncodings.size());
- // calculate worst case size where all pages are regular
- return 64 + 20 + unwindInfos.size()*8 + lsdaCount*8 + unwindInfos.size()/32 + uniqueEncodings.size()*4;
-}
-
-// Note: unwindInfos must come in sorted by functionOffset
-CompactUnwind::CompactUnwind(Architecture arch, std::vector<WriterUnwindInfo> unwindInfos)
-{
- // build new compressed list by removing entries where next function has same encoding
- // put the most common encodings into the common table, but at most 127 of them
- // build up vector of personality functions used, with an index for each
- uint32_t lsdaCount;
- CommonEncodingsMap commonEncodings;
- std::vector<UniquePersonality> personalities;
- compressDuplicates(arch, unwindInfos, lsdaCount, commonEncodings, personalities);
- // FIXME: need a way to error out if there are more than 3 personality functions used
-
- // calculate worst case size for all unwind info pages when allocating buffer
- const size_t entriesPerRegularPage = (maxPageSize-sizeof(unwind_info_regular_second_level_page_header))/sizeof(unwind_info_regular_second_level_entry);
- const size_t pageCountUpperBound = ((unwindInfos.size() - 1)/entriesPerRegularPage) + 3;
- _bytes.resize(estimateCompactUnwindTableSize(unwindInfos));
-
- // fill in section header
- unwind_info_section_header* header = (unwind_info_section_header*)&_bytes[0];
- header->version = UNWIND_SECTION_VERSION;
- header->commonEncodingsArraySectionOffset = sizeof(unwind_info_section_header);
- header->commonEncodingsArrayCount = (uint32_t)commonEncodings.size();
- header->personalityArraySectionOffset = header->commonEncodingsArraySectionOffset + (uint32_t)(commonEncodings.size()*sizeof(compact_unwind_encoding_t));
- header->personalityArrayCount = (uint32_t)personalities.size();
- header->indexSectionOffset = header->personalityArraySectionOffset + (uint32_t)(personalities.size()*sizeof(uint32_t));
- header->indexCount = 0; // fill in after second level pages built
-
- // fill in commmon encodings
- uint32_t* commonEncodingsArray = (uint32_t*)&_bytes[header->commonEncodingsArraySectionOffset];
- for (const auto& enc : commonEncodings ) {
- assert(enc.second < header->commonEncodingsArrayCount);
- commonEncodingsArray[enc.second] = enc.first;
- }
-
- // fill in personalities
- uint32_t* personalityArray = (uint32_t*)&_bytes[header->personalityArraySectionOffset];
- for (const auto& p : personalities) {
- size_t index = &p - personalities.data();
- personalityArray[index] = p.offset;
-
- uint64_t sectionOffset = (uint8_t*)&personalityArray[index] - (uint8_t*)header;
- this->_imageOffsetFixups.push_back({ p.handle, (uint32_t)sectionOffset, false });
- }
-
- // build second level pages and fill in first level as each is built
- unwind_info_section_header_index_entry* firstLevelTable = (unwind_info_section_header_index_entry*)&_bytes[header->indexSectionOffset];
- unwind_info_section_header_lsda_index_entry* lsdaContent = (unwind_info_section_header_lsda_index_entry*)&_bytes[header->indexSectionOffset+pageCountUpperBound*sizeof(unwind_info_section_header_index_entry)];
- uint8_t* secondLevelContent = (uint8_t*)&lsdaContent[lsdaCount];
- uint8_t* const firstSecondContent = secondLevelContent;
- size_t curInfosIndex = 0;
- // reserve approximate buffers for fixup vectors
- this->_imageOffsetFixups.reserve(unwindInfos.size() / 2);
- this->_diff24Fixups.reserve(unwindInfos.size() / 2);
-
- while (curInfosIndex < unwindInfos.size()) {
- uint64_t sectionOffset = (uint8_t*)&firstLevelTable[header->indexCount].functionOffset - (uint8_t*)header;
- this->_imageOffsetFixups.push_back({ unwindInfos[curInfosIndex].funcHandle,
- (uint32_t)sectionOffset,
- false });
-
- firstLevelTable[header->indexCount].functionOffset = unwindInfos[curInfosIndex].funcOffset;
- firstLevelTable[header->indexCount].secondLevelPagesSectionOffset = (uint32_t)(secondLevelContent - &_bytes[0]);
- firstLevelTable[header->indexCount].lsdaIndexArraySectionOffset = (uint32_t)((uint8_t*)lsdaContent - &_bytes[0]);
- makeCompressedSecondLevelPage(unwindInfos, commonEncodings, maxPageSize, curInfosIndex, secondLevelContent, lsdaContent);
-
- header->indexCount++;
- // 8-byte align next page
- secondLevelContent = (uint8_t*)(((uintptr_t)secondLevelContent+7) & (-8));
- }
- // add extra top level index to denote the end
- {
- firstLevelTable[header->indexCount].functionOffset = unwindInfos.back().funcOffset;
- firstLevelTable[header->indexCount].secondLevelPagesSectionOffset = 0;
- firstLevelTable[header->indexCount].lsdaIndexArraySectionOffset = (uint32_t)(firstSecondContent - &_bytes[0]);
-
- uint64_t sectionOffset = (uint8_t*)&firstLevelTable[header->indexCount].functionOffset - (uint8_t*)header;
- this->_imageOffsetFixups.push_back({
- unwindInfos.back().funcHandle,
- (uint32_t)sectionOffset,
- true
- });
-
- header->indexCount++;
- }
-
- assert(header->indexCount <= pageCountUpperBound && "not enough space reserved for compact unwind first level table");
-
- // update pointers to the constructed table can be used
- //fprintf(stderr, "est-size=%lu, act-size=%lu, ext2=%lu\n", _bytes.size(), secondLevelContent-&_bytes[0], estimateCompactUnwindTableSize(unwindInfos));
- assert(secondLevelContent <= &_bytes[_bytes.size()]);
- _bytes.resize(secondLevelContent-&_bytes[0]);
- _unwindTable = header;
- _unwindTableSize = _bytes.size();
-}
-
-
-
-#endif // BUILDING_MACHO_WRITER
-
-
} // namespace mach_o