contrib/llvm/lib/CodeGen/AsmPrinter/AddressPool.cpp

   1 //===- llvm/CodeGen/AddressPool.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 "AddressPool.h"
  11 #include "llvm/ADT/SmallVector.h"
  12 #include "llvm/CodeGen/AsmPrinter.h"
  13 #include "llvm/IR/DataLayout.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   HasBeenUsed = true;
  22   auto IterBool =
  23       Pool.insert(std::make_pair(Sym, AddressPoolEntry(Pool.size(), TLS)));
  24   return IterBool.first->second.Number;
  25 }
  26
  27
  28 void AddressPool::emitHeader(AsmPrinter &Asm, MCSection *Section) {
  29   static const uint8_t AddrSize = Asm.getDataLayout().getPointerSize();
  30   Asm.OutStreamer->SwitchSection(Section);
  31
  32   uint64_t Length = sizeof(uint16_t) // version
  33                   + sizeof(uint8_t)  // address_size
  34                   + sizeof(uint8_t)  // segment_selector_size
  35                   + AddrSize * Pool.size(); // entries
  36   Asm.emitInt32(Length); // TODO: Support DWARF64 format.
  37   Asm.emitInt16(Asm.getDwarfVersion());
  38   Asm.emitInt8(AddrSize);
  39   Asm.emitInt8(0); // TODO: Support non-zero segment_selector_size.
  40 }
  41
  42 // Emit addresses into the section given.
  43 void AddressPool::emit(AsmPrinter &Asm, MCSection *AddrSection) {
  44   if (Asm.getDwarfVersion() >= 5)
  45     emitHeader(Asm, AddrSection);
  46
  47   if (Pool.empty())
  48     return;
  49
  50   // Start the dwarf addr section.
  51   Asm.OutStreamer->SwitchSection(AddrSection);
  52
  53   // Order the address pool entries by ID
  54   SmallVector<const MCExpr *, 64> Entries(Pool.size());
  55
  56   for (const auto &I : Pool)
  57     Entries[I.second.Number] =
  58         I.second.TLS
  59             ? Asm.getObjFileLowering().getDebugThreadLocalSymbol(I.first)
  60             : MCSymbolRefExpr::create(I.first, Asm.OutContext);
  61
  62   for (const MCExpr *Entry : Entries)
  63     Asm.OutStreamer->EmitValue(Entry, Asm.getDataLayout().getPointerSize());
  64 }