llvm/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                                          uint32_t Subsection) const {
  40   // standard sections don't require the '.section'
  41   if (shouldOmitSectionDirective(getName(), MAI)) {
  42     OS << '\t' << getName() << '\n';
  43     return;
  44   }
  45
  46   OS << "\t.section\t" << getName() << ",\"";
  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(getName()))
  65     OS << 'D';
  66   if (getCharacteristics() & COFF::IMAGE_SCN_LNK_INFO)
  67     OS << 'i';
  68   OS << '"';
  69
  70   if (getCharacteristics() & COFF::IMAGE_SCN_LNK_COMDAT) {
  71     if (COMDATSymbol)
  72       OS << ",";
  73     else
  74       OS << "\n\t.linkonce\t";
  75     switch (Selection) {
  76       case COFF::IMAGE_COMDAT_SELECT_NODUPLICATES:
  77         OS << "one_only";
  78         break;
  79       case COFF::IMAGE_COMDAT_SELECT_ANY:
  80         OS << "discard";
  81         break;
  82       case COFF::IMAGE_COMDAT_SELECT_SAME_SIZE:
  83         OS << "same_size";
  84         break;
  85       case COFF::IMAGE_COMDAT_SELECT_EXACT_MATCH:
  86         OS << "same_contents";
  87         break;
  88       case COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE:
  89         OS << "associative";
  90         break;
  91       case COFF::IMAGE_COMDAT_SELECT_LARGEST:
  92         OS << "largest";
  93         break;
  94       case COFF::IMAGE_COMDAT_SELECT_NEWEST:
  95         OS << "newest";
  96         break;
  97       default:
  98         assert(false && "unsupported COFF selection type");
  99         break;
 100     }
 101     if (COMDATSymbol) {
 102       OS << ",";
 103       COMDATSymbol->print(OS, &MAI);
 104     }
 105   }
 106   OS << '\n';
 107 }
 108
 109 bool MCSectionCOFF::useCodeAlign() const { return isText(); }
 110
 111 StringRef MCSectionCOFF::getVirtualSectionKind() const {
 112   return "IMAGE_SCN_CNT_UNINITIALIZED_DATA";
 113 }