lib/MC/MCSectionCOFF.cpp

   1 //===- lib/MC/MCSectionCOFF.cpp - COFF Code Section Representation --------===//
   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 "llvm/MC/MCSectionCOFF.h"
  10 #include "llvm/BinaryFormat/COFF.h"
  11 #include "llvm/MC/MCSymbol.h"
  12 #include "llvm/Support/raw_ostream.h"
  13 #include <cassert>
  14
  15 using namespace llvm;
  16
  17 // ShouldOmitSectionDirective - Decides whether a '.section' directive
  18 // should be printed before the section name
  19 bool MCSectionCOFF::ShouldOmitSectionDirective(StringRef Name,
  20                                                const MCAsmInfo &MAI) const {
  21   if (COMDATSymbol)
  22     return false;
  23
  24   // FIXME: Does .section .bss/.data/.text work everywhere??
  25   if (Name == ".text" || Name == ".data" || Name == ".bss")
  26     return true;
  27
  28   return false;
  29 }
  30
  31 void MCSectionCOFF::setSelection(int Selection) const {
  32   assert(Selection != 0 && "invalid COMDAT selection type");
  33   this->Selection = Selection;
  34   Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
  35 }
  36
  37 void MCSectionCOFF::PrintSwitchToSection(const MCAsmInfo &MAI, const Triple &T,
  38                                          raw_ostream &OS,
  39                                          const MCExpr *Subsection) const {
  40   // standard sections don't require the '.section'
  41   if (ShouldOmitSectionDirective(SectionName, MAI)) {
  42     OS << '\t' << getSectionName() << '\n';
  43     return;
  44   }
  45
  46   OS << "\t.section\t" << getSectionName() << ",\"";
  47   if (getCharacteristics() & COFF::IMAGE_SCN_CNT_INITIALIZED_DATA)
  48     OS << 'd';
  49   if (getCharacteristics() & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA)
  50     OS << 'b';
  51   if (getCharacteristics() & COFF::IMAGE_SCN_MEM_EXECUTE)
  52     OS << 'x';
  53   if (getCharacteristics() & COFF::IMAGE_SCN_MEM_WRITE)
  54     OS << 'w';
  55   else if (getCharacteristics() & COFF::IMAGE_SCN_MEM_READ)
  56     OS << 'r';
  57   else
  58     OS << 'y';
  59   if (getCharacteristics() & COFF::IMAGE_SCN_LNK_REMOVE)
  60     OS << 'n';
  61   if (getCharacteristics() & COFF::IMAGE_SCN_MEM_SHARED)
  62     OS << 's';
  63   if ((getCharacteristics() & COFF::IMAGE_SCN_MEM_DISCARDABLE) &&
  64       !isImplicitlyDiscardable(SectionName))
  65     OS << 'D';
  66   OS << '"';
  67
  68   if (getCharacteristics() & COFF::IMAGE_SCN_LNK_COMDAT) {
  69     if (COMDATSymbol)
  70       OS << ",";
  71     else
  72       OS << "\n\t.linkonce\t";
  73     switch (Selection) {
  74       case COFF::IMAGE_COMDAT_SELECT_NODUPLICATES:
  75         OS << "one_only";
  76         break;
  77       case COFF::IMAGE_COMDAT_SELECT_ANY:
  78         OS << "discard";
  79         break;
  80       case COFF::IMAGE_COMDAT_SELECT_SAME_SIZE:
  81         OS << "same_size";
  82         break;
  83       case COFF::IMAGE_COMDAT_SELECT_EXACT_MATCH:
  84         OS << "same_contents";
  85         break;
  86       case COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE:
  87         OS << "associative";
  88         break;
  89       case COFF::IMAGE_COMDAT_SELECT_LARGEST:
  90         OS << "largest";
  91         break;
  92       case COFF::IMAGE_COMDAT_SELECT_NEWEST:
  93         OS << "newest";
  94         break;
  95       default:
  96         assert(false && "unsupported COFF selection type");
  97         break;
  98     }
  99     if (COMDATSymbol) {
 100       OS << ",";
 101       COMDATSymbol->print(OS, &MAI);
 102     }
 103   }
 104   OS << '\n';
 105 }
 106
 107 bool MCSectionCOFF::UseCodeAlign() const {
 108   return getKind().isText();
 109 }
 110
 111 bool MCSectionCOFF::isVirtualSection() const {
 112   return getCharacteristics() & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA;
 113 }