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,
  34                                  const MCSectionCOFF *Assoc) const {
  35   assert(Selection != 0 && "invalid COMDAT selection type");
  36   assert((Selection == COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE) ==
  37          (Assoc != nullptr) &&
  38     "associative COMDAT section must have an associated section");
  39   this->Selection = Selection;
  40   this->Assoc = Assoc;
  41   Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
  42 }
  43
  44 void MCSectionCOFF::PrintSwitchToSection(const MCAsmInfo &MAI,
  45                                          raw_ostream &OS,
  46                                          const MCExpr *Subsection) const {
  47
  48   // standard sections don't require the '.section'
  49   if (ShouldOmitSectionDirective(SectionName, MAI)) {
  50     OS << '\t' << getSectionName() << '\n';
  51     return;
  52   }
  53
  54   OS << "\t.section\t" << getSectionName() << ",\"";
  55   if (getKind().isText())
  56     OS << 'x';
  57   else if (getKind().isBSS())
  58     OS << 'b';
  59   if (getKind().isWriteable())
  60     OS << 'w';
  61   else
  62     OS << 'r';
  63   if (getCharacteristics() & COFF::IMAGE_SCN_MEM_DISCARDABLE)
  64     OS << 'n';
  65   if (getCharacteristics() & COFF::IMAGE_SCN_CNT_INITIALIZED_DATA)
  66     OS << 'd';
  67   OS << '"';
  68
  69   if (getCharacteristics() & COFF::IMAGE_SCN_LNK_COMDAT) {
  70     OS << ",";
  71     switch (Selection) {
  72       case COFF::IMAGE_COMDAT_SELECT_NODUPLICATES:
  73         OS << "one_only,";
  74         break;
  75       case COFF::IMAGE_COMDAT_SELECT_ANY:
  76         OS << "discard,";
  77         break;
  78       case COFF::IMAGE_COMDAT_SELECT_SAME_SIZE:
  79         OS << "same_size,";
  80         break;
  81       case COFF::IMAGE_COMDAT_SELECT_EXACT_MATCH:
  82         OS << "same_contents,";
  83         break;
  84       case COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE:
  85         OS << "associative " << Assoc->getSectionName() << ",";
  86         break;
  87       case COFF::IMAGE_COMDAT_SELECT_LARGEST:
  88         OS << "largest,";
  89         break;
  90       case COFF::IMAGE_COMDAT_SELECT_NEWEST:
  91         OS << "newest,";
  92         break;
  93       default:
  94         assert (0 && "unsupported COFF selection type");
  95         break;
  96     }
  97     assert(COMDATSymbol);
  98     OS << *COMDATSymbol;
  99   }
 100   OS << '\n';
 101 }
 102
 103 bool MCSectionCOFF::UseCodeAlign() const {
 104   return getKind().isText();
 105 }
 106
 107 bool MCSectionCOFF::isVirtualSection() const {
 108   return getCharacteristics() & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA;
 109 }