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 void MCSection::switchSubsection(unsigned Subsection) { 70 size_t I = 0, E = Subsections.size(); 71 while (I != E && Subsections[I].first < Subsection) 72 ++I; 73 // If the subsection number is not in the sorted Subsections list, create a 74 // new fragment list. 75 if (I == E || Subsections[I].first != Subsection) 76 Subsections.insert(Subsections.begin() + I, {Subsection, FragList{}}); 77 CurFragList = &Subsections[I].second; 78 } 79 80 StringRef MCSection::getVirtualSectionKind() const { return "virtual"; } 81 82 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) 83 LLVM_DUMP_METHOD void MCSection::dump() const { 84 raw_ostream &OS = errs(); 85 86 OS << "<MCSection Name:" << getName(); 87 OS << " Fragments:[\n "; 88 bool First = true; 89 for (auto &F : *this) { 90 if (First) 91 First = false; 92 else 93 OS << ",\n "; 94 F.dump(); 95 } 96 OS << "]>"; 97 } 98 #endif 99