1 //===-- llvm/CodeGen/DwarfStringPool.cpp - Dwarf Debug Framework ----------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 #include "DwarfStringPool.h" 11 #include "llvm/CodeGen/AsmPrinter.h" 12 #include "llvm/MC/MCStreamer.h" 13 14 using namespace llvm; 15 16 DwarfStringPool::EntryRef DwarfStringPool::getEntry(AsmPrinter &Asm, 17 StringRef Str) { 18 auto I = Pool.insert(std::make_pair(Str, EntryTy())); 19 if (I.second) { 20 auto &Entry = I.first->second; 21 Entry.Index = Pool.size() - 1; 22 Entry.Offset = NumBytes; 23 Entry.Symbol = Asm.createTempSymbol(Prefix); 24 25 NumBytes += Str.size() + 1; 26 assert(NumBytes > Entry.Offset && "Unexpected overflow"); 27 } 28 return EntryRef(*I.first); 29 } 30 31 void DwarfStringPool::emit(AsmPrinter &Asm, MCSection *StrSection, 32 MCSection *OffsetSection) { 33 if (Pool.empty()) 34 return; 35 36 // Start the dwarf str section. 37 Asm.OutStreamer->SwitchSection(StrSection); 38 39 // Get all of the string pool entries and put them in an array by their ID so 40 // we can sort them. 41 SmallVector<const StringMapEntry<EntryTy> *, 64> Entries(Pool.size()); 42 43 for (const auto &E : Pool) 44 Entries[E.getValue().Index] = &E; 45 46 for (const auto &Entry : Entries) { 47 // Emit a label for reference from debug information entries. 48 Asm.OutStreamer->EmitLabel(Entry->getValue().Symbol); 49 50 // Emit the string itself with a terminating null byte. 51 Asm.OutStreamer->AddComment("string offset=" + 52 Twine(Entry->getValue().Offset)); 53 Asm.OutStreamer->EmitBytes( 54 StringRef(Entry->getKeyData(), Entry->getKeyLength() + 1)); 55 } 56 57 // If we've got an offset section go ahead and emit that now as well. 58 if (OffsetSection) { 59 Asm.OutStreamer->SwitchSection(OffsetSection); 60 unsigned size = 4; // FIXME: DWARF64 is 8. 61 for (const auto &Entry : Entries) 62 Asm.OutStreamer->EmitIntValue(Entry->getValue().Offset, size); 63 } 64 } 65