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      1 //===- lib/MC/MCSection.cpp - Machine 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/MCSection.h"
     11 #include "llvm/MC/MCAssembler.h"
     12 #include "llvm/MC/MCAsmInfo.h"
     13 #include "llvm/MC/MCContext.h"
     14 #include "llvm/MC/MCSymbol.h"
     15 #include "llvm/Support/raw_ostream.h"
     16 using namespace llvm;
     17 
     18 //===----------------------------------------------------------------------===//
     19 // MCSection
     20 //===----------------------------------------------------------------------===//
     21 
     22 MCSection::MCSection(SectionVariant V, SectionKind K, MCSymbol *Begin)
     23     : Begin(Begin), BundleGroupBeforeFirstInst(false), HasInstructions(false),
     24       IsRegistered(false), DummyFragment(this), Variant(V), Kind(K) {}
     25 
     26 MCSymbol *MCSection::getEndSymbol(MCContext &Ctx) {
     27   if (!End)
     28     End = Ctx.createTempSymbol("sec_end", true);
     29   return End;
     30 }
     31 
     32 bool MCSection::hasEnded() const { return End && End->isInSection(); }
     33 
     34 MCSection::~MCSection() {
     35 }
     36 
     37 void MCSection::setBundleLockState(BundleLockStateType NewState) {
     38   if (NewState == NotBundleLocked) {
     39     if (BundleLockNestingDepth == 0) {
     40       report_fatal_error("Mismatched bundle_lock/unlock directives");
     41     }
     42     if (--BundleLockNestingDepth == 0) {
     43       BundleLockState = NotBundleLocked;
     44     }
     45     return;
     46   }
     47 
     48   // If any of the directives is an align_to_end directive, the whole nested
     49   // group is align_to_end. So don't downgrade from align_to_end to just locked.
     50   if (BundleLockState != BundleLockedAlignToEnd) {
     51     BundleLockState = NewState;
     52   }
     53   ++BundleLockNestingDepth;
     54 }
     55 
     56 MCSection::iterator
     57 MCSection::getSubsectionInsertionPoint(unsigned Subsection) {
     58   if (Subsection == 0 && SubsectionFragmentMap.empty())
     59     return end();
     60 
     61   SmallVectorImpl<std::pair<unsigned, MCFragment *>>::iterator MI =
     62       std::lower_bound(SubsectionFragmentMap.begin(),
     63                        SubsectionFragmentMap.end(),
     64                        std::make_pair(Subsection, (MCFragment *)nullptr));
     65   bool ExactMatch = false;
     66   if (MI != SubsectionFragmentMap.end()) {
     67     ExactMatch = MI->first == Subsection;
     68     if (ExactMatch)
     69       ++MI;
     70   }
     71   iterator IP;
     72   if (MI == SubsectionFragmentMap.end())
     73     IP = end();
     74   else
     75     IP = MI->second->getIterator();
     76   if (!ExactMatch && Subsection != 0) {
     77     // The GNU as documentation claims that subsections have an alignment of 4,
     78     // although this appears not to be the case.
     79     MCFragment *F = new MCDataFragment();
     80     SubsectionFragmentMap.insert(MI, std::make_pair(Subsection, F));
     81     getFragmentList().insert(IP, F);
     82     F->setParent(this);
     83   }
     84 
     85   return IP;
     86 }
     87 
     88 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
     89 LLVM_DUMP_METHOD void MCSection::dump() {
     90   raw_ostream &OS = llvm::errs();
     91 
     92   OS << "<MCSection";
     93   OS << " Fragments:[\n      ";
     94   for (auto it = begin(), ie = end(); it != ie; ++it) {
     95     if (it != begin())
     96       OS << ",\n      ";
     97     it->dump();
     98   }
     99   OS << "]>";
    100 }
    101 #endif
    102 
    103 MCSection::iterator MCSection::begin() { return Fragments.begin(); }
    104 
    105 MCSection::iterator MCSection::end() { return Fragments.end(); }
    106 
    107 MCSection::reverse_iterator MCSection::rbegin() { return Fragments.rbegin(); }
    108 
    109 MCSection::reverse_iterator MCSection::rend() { return Fragments.rend(); }
    110