-
-bool RuntimeDyldMachO::
-loadSegment64(const MachOObject *Obj,
- const MachOObject::LoadCommandInfo *SegmentLCI,
- const InMemoryStruct<macho::SymtabLoadCommand> &SymtabLC) {
- InMemoryStruct<macho::Segment64LoadCommand> Segment64LC;
- Obj->ReadSegment64LoadCommand(*SegmentLCI, Segment64LC);
- if (!Segment64LC)
- return Error("unable to load segment load command");
-
- for (unsigned SectNum = 0; SectNum != Segment64LC->NumSections; ++SectNum) {
- InMemoryStruct<macho::Section64> Sect;
- Obj->ReadSection64(*SegmentLCI, SectNum, Sect);
- if (!Sect)
- return Error("unable to load section: '" + Twine(SectNum) + "'");
-
- // FIXME: For the time being, we're only loading text segments.
- if (Sect->Flags != 0x80000400)
- continue;
-
- // Address and names of symbols in the section.
- typedef std::pair<uint64_t, StringRef> SymbolEntry;
- SmallVector<SymbolEntry, 64> Symbols;
- // Index of all the names, in this section or not. Used when we're
- // dealing with relocation entries.
- SmallVector<StringRef, 64> SymbolNames;
- for (unsigned i = 0; i != SymtabLC->NumSymbolTableEntries; ++i) {
- InMemoryStruct<macho::Symbol64TableEntry> STE;
- Obj->ReadSymbol64TableEntry(SymtabLC->SymbolTableOffset, i, STE);
- if (!STE)
- return Error("unable to read symbol: '" + Twine(i) + "'");
- if (STE->SectionIndex > Segment64LC->NumSections)
- return Error("invalid section index for symbol: '" + Twine(i) + "'");
- // Get the symbol name.
- StringRef Name = Obj->getStringAtIndex(STE->StringIndex);
- SymbolNames.push_back(Name);
-
- // Just skip symbols not defined in this section.
- if ((unsigned)STE->SectionIndex - 1 != SectNum)
- continue;
-
- // FIXME: Check the symbol type and flags.
- if (STE->Type != 0xF) // external, defined in this section.
- continue;
- // Flags in the upper nibble we don't care about.
- if ((STE->Flags & 0xf) != 0x0)
- continue;
-
- // Remember the symbol.
- Symbols.push_back(SymbolEntry(STE->Value, Name));
-
- DEBUG(dbgs() << "Function sym: '" << Name << "' @ " <<
- (Sect->Address + STE->Value) << "\n");
- }
- // Sort the symbols by address, just in case they didn't come in that way.
- array_pod_sort(Symbols.begin(), Symbols.end());
-
- // If there weren't any functions (odd, but just in case...)
- if (!Symbols.size())
- continue;
-
- // Extract the function data.
- uint8_t *Base = (uint8_t*)Obj->getData(Segment64LC->FileOffset,
- Segment64LC->FileSize).data();
- for (unsigned i = 0, e = Symbols.size() - 1; i != e; ++i) {
- uint64_t StartOffset = Sect->Address + Symbols[i].first;
- uint64_t EndOffset = Symbols[i + 1].first - 1;
- DEBUG(dbgs() << "Extracting function: " << Symbols[i].second
- << " from [" << StartOffset << ", " << EndOffset << "]\n");
- extractFunction(Symbols[i].second, Base + StartOffset, Base + EndOffset);
- }
- // The last symbol we do after since the end address is calculated
- // differently because there is no next symbol to reference.
- uint64_t StartOffset = Symbols[Symbols.size() - 1].first;
- uint64_t EndOffset = Sect->Size - 1;
- DEBUG(dbgs() << "Extracting function: " << Symbols[Symbols.size()-1].second
- << " from [" << StartOffset << ", " << EndOffset << "]\n");
- extractFunction(Symbols[Symbols.size()-1].second,
- Base + StartOffset, Base + EndOffset);
-
- // Now extract the relocation information for each function and process it.
- for (unsigned j = 0; j != Sect->NumRelocationTableEntries; ++j) {
- InMemoryStruct<macho::RelocationEntry> RE;
- Obj->ReadRelocationEntry(Sect->RelocationTableOffset, j, RE);
- if (RE->Word0 & macho::RF_Scattered)
- return Error("NOT YET IMPLEMENTED: scattered relocations.");
- // Word0 of the relocation is the offset into the section where the
- // relocation should be applied. We need to translate that into an
- // offset into a function since that's our atom.
- uint32_t Offset = RE->Word0;
- // Look for the function containing the address. This is used for JIT
- // code, so the number of functions in section is almost always going
- // to be very small (usually just one), so until we have use cases
- // where that's not true, just use a trivial linear search.
- unsigned SymbolNum;
- unsigned NumSymbols = Symbols.size();
- assert(NumSymbols > 0 && Symbols[0].first <= Offset &&
- "No symbol containing relocation!");
- for (SymbolNum = 0; SymbolNum < NumSymbols - 1; ++SymbolNum)
- if (Symbols[SymbolNum + 1].first > Offset)
- break;
- // Adjust the offset to be relative to the symbol.
- Offset -= Symbols[SymbolNum].first;
- // Get the name of the symbol containing the relocation.
- StringRef TargetName = SymbolNames[SymbolNum];
-
- bool isExtern = (RE->Word1 >> 27) & 1;
- // Figure out the source symbol of the relocation. If isExtern is true,
- // this relocation references the symbol table, otherwise it references
- // a section in the same object, numbered from 1 through NumSections
- // (SectionBases is [0, NumSections-1]).
- if (!isExtern)
- return Error("Internal relocations not supported.");
- uint32_t SourceNum = RE->Word1 & 0xffffff; // 24-bit value
- StringRef SourceName = SymbolNames[SourceNum];
-
- // FIXME: Get the relocation addend from the target address.
-
- // Now store the relocation information. Associate it with the source
- // symbol.
- Relocations[SourceName].push_back(RelocationEntry(TargetName,
- Offset,
- RE->Word1,
- 0 /*Addend*/));
- DEBUG(dbgs() << "Relocation at '" << TargetName << "' + " << Offset
- << " from '" << SourceName << "(Word1: "
- << format("0x%x", RE->Word1) << ")\n");
- }
- }