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      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/COFF.h"
     15 #include "llvm/Support/raw_ostream.h"
     16 using namespace llvm;
     17 
     18 MCSectionCOFF::~MCSectionCOFF() {} // anchor.
     19 
     20 // ShouldOmitSectionDirective - Decides whether a '.section' directive
     21 // should be printed before the section name
     22 bool MCSectionCOFF::ShouldOmitSectionDirective(StringRef Name,
     23                                                const MCAsmInfo &MAI) const {
     24   if (COMDATSymbol)
     25     return false;
     26 
     27   // FIXME: Does .section .bss/.data/.text work everywhere??
     28   if (Name == ".text" || Name == ".data" || Name == ".bss")
     29     return true;
     30 
     31   return false;
     32 }
     33 
     34 void MCSectionCOFF::setSelection(int Selection) const {
     35   assert(Selection != 0 && "invalid COMDAT selection type");
     36   this->Selection = Selection;
     37   Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
     38 }
     39 
     40 void MCSectionCOFF::PrintSwitchToSection(const MCAsmInfo &MAI,
     41                                          raw_ostream &OS,
     42                                          const MCExpr *Subsection) const {
     43 
     44   // standard sections don't require the '.section'
     45   if (ShouldOmitSectionDirective(SectionName, MAI)) {
     46     OS << '\t' << getSectionName() << '\n';
     47     return;
     48   }
     49 
     50   OS << "\t.section\t" << getSectionName() << ",\"";
     51   if (getCharacteristics() & COFF::IMAGE_SCN_CNT_INITIALIZED_DATA)
     52     OS << 'd';
     53   if (getCharacteristics() & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA)
     54     OS << 'b';
     55   if (getCharacteristics() & COFF::IMAGE_SCN_MEM_EXECUTE)
     56     OS << 'x';
     57   if (getCharacteristics() & COFF::IMAGE_SCN_MEM_WRITE)
     58     OS << 'w';
     59   else if (getCharacteristics() & COFF::IMAGE_SCN_MEM_READ)
     60     OS << 'r';
     61   else
     62     OS << 'y';
     63   if (getCharacteristics() & COFF::IMAGE_SCN_LNK_REMOVE)
     64     OS << 'n';
     65   if (getCharacteristics() & COFF::IMAGE_SCN_MEM_SHARED)
     66     OS << 's';
     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,";
     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     COMDATSymbol->print(OS, &MAI);
     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 }
    110