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/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 <algorithm>
20 #include <utility>
21
22 using namespace llvm;
23
MCSection(SectionVariant V,SectionKind K,MCSymbol * Begin)24 MCSection::MCSection(SectionVariant V, SectionKind K, MCSymbol *Begin)
25 : Begin(Begin), BundleGroupBeforeFirstInst(false), HasInstructions(false),
26 IsRegistered(false), DummyFragment(this), Variant(V), Kind(K) {}
27
getEndSymbol(MCContext & Ctx)28 MCSymbol *MCSection::getEndSymbol(MCContext &Ctx) {
29 if (!End)
30 End = Ctx.createTempSymbol("sec_end", true);
31 return End;
32 }
33
hasEnded() const34 bool MCSection::hasEnded() const { return End && End->isInSection(); }
35
36 MCSection::~MCSection() = default;
37
setBundleLockState(BundleLockStateType NewState)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
getSubsectionInsertionPoint(unsigned Subsection)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)
dump() const90 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