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 103