lib/MC/MCSectionCOFF.cpp

   1 //===- lib/MC/MCSectionCOFF.cpp - COFF Code Section Representation --------===//
   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 "llvm/MC/MCSectionCOFF.h"
  11 #include "llvm/MC/MCAsmInfo.h"
  12 #include "llvm/MC/MCContext.h"
  13 #include "llvm/MC/MCSymbol.h"
  14 #include "llvm/Support/raw_ostream.h"
  15 using namespace llvm;
  16
  17 MCSectionCOFF::~MCSectionCOFF() {} // anchor.
  18
  19 // ShouldOmitSectionDirective - Decides whether a '.section' directive
  20 // should be printed before the section name
  21 bool MCSectionCOFF::ShouldOmitSectionDirective(StringRef Name,
  22                                                const MCAsmInfo &MAI) const {
  23   if (COMDATSymbol)
  24     return false;
  25
  26   // FIXME: Does .section .bss/.data/.text work everywhere??
  27   if (Name == ".text" || Name == ".data" || Name == ".bss")
  28     return true;
  29
  30   return false;
  31 }
  32
  33 void MCSectionCOFF::setSelection(int Selection) const {
  34   assert(Selection != 0 && "invalid COMDAT selection type");
  35   this->Selection = Selection;
  36   Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
  37 }
  38
  39 void MCSectionCOFF::PrintSwitchToSection(const MCAsmInfo &MAI,
  40                                          raw_ostream &OS,
  41                                          const MCExpr *Subsection) const {
  42
  43   // standard sections don't require the '.section'
  44   if (ShouldOmitSectionDirective(SectionName, MAI)) {
  45     OS << '\t' << getSectionName() << '\n';
  46     return;
  47   }
  48
  49   OS << "\t.section\t" << getSectionName() << ",\"";
  50   if (getCharacteristics() & COFF::IMAGE_SCN_CNT_INITIALIZED_DATA)
  51     OS << 'd';
  52   if (getCharacteristics() & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA)
  53     OS << 'b';
  54   if (getCharacteristics() & COFF::IMAGE_SCN_MEM_EXECUTE)
  55     OS << 'x';
  56   if (getCharacteristics() & COFF::IMAGE_SCN_MEM_WRITE)
  57     OS << 'w';
  58   else if (getCharacteristics() & COFF::IMAGE_SCN_MEM_READ)
  59     OS << 'r';
  60   else
  61     OS << 'y';
  62   if (getCharacteristics() & COFF::IMAGE_SCN_LNK_REMOVE)
  63     OS << 'n';
  64   if (getCharacteristics() & COFF::IMAGE_SCN_MEM_SHARED)
  65     OS << 's';
  66   OS << '"';
  67
  68   if (getCharacteristics() & COFF::IMAGE_SCN_LNK_COMDAT) {
  69     OS << ",";
  70     switch (Selection) {
  71       case COFF::IMAGE_COMDAT_SELECT_NODUPLICATES:
  72         OS << "one_only,";
  73         break;
  74       case COFF::IMAGE_COMDAT_SELECT_ANY:
  75         OS << "discard,";
  76         break;
  77       case COFF::IMAGE_COMDAT_SELECT_SAME_SIZE:
  78         OS << "same_size,";
  79         break;
  80       case COFF::IMAGE_COMDAT_SELECT_EXACT_MATCH:
  81         OS << "same_contents,";
  82         break;
  83       case COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE:
  84         OS << "associative,";
  85         break;
  86       case COFF::IMAGE_COMDAT_SELECT_LARGEST:
  87         OS << "largest,";
  88         break;
  89       case COFF::IMAGE_COMDAT_SELECT_NEWEST:
  90         OS << "newest,";
  91         break;
  92       default:
  93         assert (0 && "unsupported COFF selection type");
  94         break;
  95     }
  96     assert(COMDATSymbol);
  97     OS << *COMDATSymbol;
  98   }
  99   OS << '\n';
 100 }
 101
 102 bool MCSectionCOFF::UseCodeAlign() const {
 103   return getKind().isText();
 104 }
 105
 106 bool MCSectionCOFF::isVirtualSection() const {
 107   return getCharacteristics() & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA;
 108 }