lib/MC/MCSection.cpp

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