llvm/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/STLExtras.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 <utility>
  20
  21 using namespace llvm;
  22
  23 MCSection::MCSection(SectionVariant V, StringRef Name, bool IsText,
  24                      bool IsVirtual, MCSymbol *Begin)
  25     : Begin(Begin), BundleGroupBeforeFirstInst(false), HasInstructions(false),
  26       HasLayout(false), IsRegistered(false), IsText(IsText),
  27       IsVirtual(IsVirtual), Name(Name), Variant(V) {
  28   DummyFragment.setParent(this);
  29   // The initial subsection number is 0. Create a fragment list.
  30   CurFragList = &Subsections.emplace_back(0u, FragList{}).second;
  31 }
  32
  33 MCSymbol *MCSection::getEndSymbol(MCContext &Ctx) {
  34   if (!End)
  35     End = Ctx.createTempSymbol("sec_end");
  36   return End;
  37 }
  38
  39 bool MCSection::hasEnded() const { return End && End->isInSection(); }
  40
  41 MCSection::~MCSection() {
  42   for (auto &[_, Chain] : Subsections) {
  43     for (MCFragment *X = Chain.Head, *Y; X; X = Y) {
  44       Y = X->Next;
  45       X->destroy();
  46     }
  47   }
  48 }
  49
  50 void MCSection::setBundleLockState(BundleLockStateType NewState) {
  51   if (NewState == NotBundleLocked) {
  52     if (BundleLockNestingDepth == 0) {
  53       report_fatal_error("Mismatched bundle_lock/unlock directives");
  54     }
  55     if (--BundleLockNestingDepth == 0) {
  56       BundleLockState = NotBundleLocked;
  57     }
  58     return;
  59   }
  60
  61   // If any of the directives is an align_to_end directive, the whole nested
  62   // group is align_to_end. So don't downgrade from align_to_end to just locked.
  63   if (BundleLockState != BundleLockedAlignToEnd) {
  64     BundleLockState = NewState;
  65   }
  66   ++BundleLockNestingDepth;
  67 }
  68
  69 StringRef MCSection::getVirtualSectionKind() const { return "virtual"; }
  70
  71 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
  72 LLVM_DUMP_METHOD void MCSection::dump() const {
  73   raw_ostream &OS = errs();
  74
  75   OS << "<MCSection Name:" << getName();
  76   OS << " Fragments:[\n      ";
  77   bool First = true;
  78   for (auto &F : *this) {
  79     if (First)
  80       First = false;
  81     else
  82       OS << ",\n      ";
  83     F.dump();
  84   }
  85   OS << "]>";
  86 }
  87 #endif