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8 | 8 |
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9 | 9 | #include "BPSectionOrderer.h" |
10 | 10 | #include "InputSection.h" |
| 11 | +#include "Relocations.h" |
| 12 | +#include "Symbols.h" |
| 13 | +#include "lld/Common/BPSectionOrdererBase.inc" |
11 | 14 | #include "llvm/ADT/DenseMap.h" |
| 15 | +#include "llvm/ADT/StableHashing.h" |
| 16 | +#include "llvm/Support/Endian.h" |
| 17 | +#include "llvm/Support/xxhash.h" |
12 | 18 |
|
13 | 19 | #define DEBUG_TYPE "bp-section-orderer" |
14 | 20 |
|
15 | 21 | using namespace llvm; |
16 | 22 | using namespace lld::macho; |
17 | 23 |
|
| 24 | +namespace { |
| 25 | +struct BPOrdererMachO; |
| 26 | +} |
| 27 | +template <> struct lld::BPOrdererTraits<struct BPOrdererMachO> { |
| 28 | + using Section = macho::InputSection; |
| 29 | + using Symbol = macho::Symbol; |
| 30 | +}; |
| 31 | +namespace { |
| 32 | +struct BPOrdererMachO : lld::BPOrderer<BPOrdererMachO> { |
| 33 | + static uint64_t getSize(const Section &sec) { return sec.getSize(); } |
| 34 | + static bool isCodeSection(const Section &sec) { |
| 35 | + return macho::isCodeSection(&sec); |
| 36 | + } |
| 37 | + static SmallVector<Symbol *, 0> getSymbols(const Section &sec) { |
| 38 | + SmallVector<Symbol *, 0> symbols; |
| 39 | + for (auto *sym : sec.symbols) |
| 40 | + if (auto *d = llvm::dyn_cast_or_null<Defined>(sym)) |
| 41 | + symbols.emplace_back(d); |
| 42 | + return symbols; |
| 43 | + } |
| 44 | + |
| 45 | + // Linkage names can be prefixed with "_" or "l_" on Mach-O. See |
| 46 | + // Mangler::getNameWithPrefix() for details. |
| 47 | + std::optional<StringRef> static getResolvedLinkageName(llvm::StringRef name) { |
| 48 | + if (name.consume_front("_") || name.consume_front("l_")) |
| 49 | + return name; |
| 50 | + return {}; |
| 51 | + } |
| 52 | + |
| 53 | + static void |
| 54 | + getSectionHashes(const Section &sec, llvm::SmallVectorImpl<uint64_t> &hashes, |
| 55 | + const llvm::DenseMap<const void *, uint64_t> §ionToIdx) { |
| 56 | + constexpr unsigned windowSize = 4; |
| 57 | + |
| 58 | + // Calculate content hashes: k-mers and the last k-1 bytes. |
| 59 | + ArrayRef<uint8_t> data = sec.data; |
| 60 | + if (data.size() >= windowSize) |
| 61 | + for (size_t i = 0; i <= data.size() - windowSize; ++i) |
| 62 | + hashes.push_back(llvm::support::endian::read32le(data.data() + i)); |
| 63 | + for (uint8_t byte : data.take_back(windowSize - 1)) |
| 64 | + hashes.push_back(byte); |
| 65 | + |
| 66 | + // Calculate relocation hashes |
| 67 | + for (const auto &r : sec.relocs) { |
| 68 | + if (r.length == 0 || r.referent.isNull() || r.offset >= data.size()) |
| 69 | + continue; |
| 70 | + |
| 71 | + uint64_t relocHash = getRelocHash(r, sectionToIdx); |
| 72 | + uint32_t start = (r.offset < windowSize) ? 0 : r.offset - windowSize + 1; |
| 73 | + for (uint32_t i = start; i < r.offset + r.length; i++) { |
| 74 | + auto window = data.drop_front(i).take_front(windowSize); |
| 75 | + hashes.push_back(xxh3_64bits(window) ^ relocHash); |
| 76 | + } |
| 77 | + } |
| 78 | + |
| 79 | + llvm::sort(hashes); |
| 80 | + hashes.erase(std::unique(hashes.begin(), hashes.end()), hashes.end()); |
| 81 | + } |
| 82 | + |
| 83 | + static llvm::StringRef getSymName(const Symbol &sym) { return sym.getName(); } |
| 84 | + static uint64_t getSymValue(const Symbol &sym) { |
| 85 | + if (auto *d = dyn_cast<Defined>(&sym)) |
| 86 | + return d->value; |
| 87 | + return 0; |
| 88 | + } |
| 89 | + static uint64_t getSymSize(const Symbol &sym) { |
| 90 | + if (auto *d = dyn_cast<Defined>(&sym)) |
| 91 | + return d->size; |
| 92 | + return 0; |
| 93 | + } |
| 94 | + |
| 95 | +private: |
| 96 | + static uint64_t |
| 97 | + getRelocHash(const Reloc &reloc, |
| 98 | + const llvm::DenseMap<const void *, uint64_t> §ionToIdx) { |
| 99 | + auto *isec = reloc.getReferentInputSection(); |
| 100 | + std::optional<uint64_t> sectionIdx; |
| 101 | + if (auto it = sectionToIdx.find(isec); it != sectionToIdx.end()) |
| 102 | + sectionIdx = it->second; |
| 103 | + uint64_t kind = -1, value = 0; |
| 104 | + if (isec) |
| 105 | + kind = uint64_t(isec->kind()); |
| 106 | + |
| 107 | + if (auto *sym = reloc.referent.dyn_cast<Symbol *>()) { |
| 108 | + kind = (kind << 8) | uint8_t(sym->kind()); |
| 109 | + if (auto *d = llvm::dyn_cast<Defined>(sym)) |
| 110 | + value = d->value; |
| 111 | + } |
| 112 | + return llvm::stable_hash_combine(kind, sectionIdx.value_or(0), value, |
| 113 | + reloc.addend); |
| 114 | + } |
| 115 | +}; |
| 116 | +} // namespace |
| 117 | + |
18 | 118 | DenseMap<const InputSection *, int> lld::macho::runBalancedPartitioning( |
19 | 119 | StringRef profilePath, bool forFunctionCompression, bool forDataCompression, |
20 | 120 | bool compressionSortStartupFunctions, bool verbose) { |
21 | | - |
22 | | - SmallVector<std::unique_ptr<BPSectionBase>> sections; |
| 121 | + // Collect candidate sections and associated symbols. |
| 122 | + SmallVector<InputSection *> sections; |
| 123 | + DenseMap<CachedHashStringRef, DenseSet<unsigned>> rootSymbolToSectionIdxs; |
23 | 124 | for (const auto *file : inputFiles) { |
24 | 125 | for (auto *sec : file->sections) { |
25 | 126 | for (auto &subsec : sec->subsections) { |
26 | 127 | auto *isec = subsec.isec; |
27 | | - if (!isec || isec->data.empty() || !isec->data.data()) |
| 128 | + if (!isec || isec->data.empty()) |
28 | 129 | continue; |
29 | | - sections.emplace_back(std::make_unique<BPSectionMacho>(isec)); |
| 130 | + size_t idx = sections.size(); |
| 131 | + sections.emplace_back(isec); |
| 132 | + for (auto *sym : BPOrdererMachO::getSymbols(*isec)) { |
| 133 | + auto rootName = getRootSymbol(sym->getName()); |
| 134 | + rootSymbolToSectionIdxs[CachedHashStringRef(rootName)].insert(idx); |
| 135 | + if (auto linkageName = |
| 136 | + BPOrdererMachO::getResolvedLinkageName(rootName)) |
| 137 | + rootSymbolToSectionIdxs[CachedHashStringRef(*linkageName)].insert( |
| 138 | + idx); |
| 139 | + } |
30 | 140 | } |
31 | 141 | } |
32 | 142 | } |
33 | 143 |
|
34 | | - auto reorderedSections = BPSectionBase::reorderSectionsByBalancedPartitioning( |
35 | | - profilePath, forFunctionCompression, forDataCompression, |
36 | | - compressionSortStartupFunctions, verbose, sections); |
37 | | - |
38 | | - DenseMap<const InputSection *, int> result; |
39 | | - for (const auto &[sec, priority] : reorderedSections) { |
40 | | - result.try_emplace( |
41 | | - static_cast<const InputSection *>( |
42 | | - static_cast<const BPSectionMacho *>(sec)->getSection()), |
43 | | - priority); |
44 | | - } |
45 | | - return result; |
| 144 | + return BPOrdererMachO::computeOrder(profilePath, forFunctionCompression, |
| 145 | + forDataCompression, |
| 146 | + compressionSortStartupFunctions, verbose, |
| 147 | + sections, rootSymbolToSectionIdxs); |
46 | 148 | } |
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