1 //===- llvm/CodeGen/AddressPool.cpp - Dwarf Debug Framework ---------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "AddressPool.h" 10 #include "llvm/ADT/SmallVector.h" 11 #include "llvm/CodeGen/AsmPrinter.h" 12 #include "llvm/IR/DataLayout.h" 13 #include "llvm/MC/MCAsmInfo.h" 14 #include "llvm/MC/MCStreamer.h" 15 #include "llvm/Target/TargetLoweringObjectFile.h" 16 #include <utility> 17 18 using namespace llvm; 19 20 unsigned AddressPool::getIndex(const MCSymbol *Sym, bool TLS) { 21 resetUsedFlag(true); 22 auto IterBool = 23 Pool.insert(std::make_pair(Sym, AddressPoolEntry(Pool.size(), TLS))); 24 return IterBool.first->second.Number; 25 } 26 27 MCSymbol *AddressPool::emitHeader(AsmPrinter &Asm, MCSection *Section) { 28 static const uint8_t AddrSize = Asm.MAI->getCodePointerSize(); 29 30 MCSymbol *EndLabel = 31 Asm.emitDwarfUnitLength("debug_addr", "Length of contribution"); 32 Asm.OutStreamer->AddComment("DWARF version number"); 33 Asm.emitInt16(Asm.getDwarfVersion()); 34 Asm.OutStreamer->AddComment("Address size"); 35 Asm.emitInt8(AddrSize); 36 Asm.OutStreamer->AddComment("Segment selector size"); 37 Asm.emitInt8(0); // TODO: Support non-zero segment_selector_size. 38 39 return EndLabel; 40 } 41 42 // Emit addresses into the section given. 43 void AddressPool::emit(AsmPrinter &Asm, MCSection *AddrSection) { 44 if (isEmpty()) 45 return; 46 47 // Start the dwarf addr section. 48 Asm.OutStreamer->switchSection(AddrSection); 49 50 MCSymbol *EndLabel = nullptr; 51 52 if (Asm.getDwarfVersion() >= 5) 53 EndLabel = emitHeader(Asm, AddrSection); 54 55 // Define the symbol that marks the start of the contribution. 56 // It is referenced via DW_AT_addr_base. 57 Asm.OutStreamer->emitLabel(AddressTableBaseSym); 58 59 // Order the address pool entries by ID 60 SmallVector<const MCExpr *, 64> Entries(Pool.size()); 61 62 for (const auto &I : Pool) 63 Entries[I.second.Number] = 64 I.second.TLS 65 ? Asm.getObjFileLowering().getDebugThreadLocalSymbol(I.first) 66 : MCSymbolRefExpr::create(I.first, Asm.OutContext); 67 68 for (const MCExpr *Entry : Entries) 69 Asm.OutStreamer->emitValue(Entry, Asm.MAI->getCodePointerSize()); 70 71 if (EndLabel) 72 Asm.OutStreamer->emitLabel(EndLabel); 73 } 74