lib/MC/MCSection.cpp

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