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