1//===- lib/MC/MCSectionELF.cpp - ELF 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/MCSectionELF.h"
11#include "llvm/MC/MCAsmInfo.h"
12#include "llvm/MC/MCContext.h"
13#include "llvm/MC/MCExpr.h"
14#include "llvm/MC/MCSymbol.h"
15#include "llvm/Support/ELF.h"
16#include "llvm/Support/raw_ostream.h"
17
18using namespace llvm;
19
20MCSectionELF::~MCSectionELF() {} // anchor.
21
22// Decides whether a '.section' directive
23// should be printed before the section name.
24bool MCSectionELF::ShouldOmitSectionDirective(StringRef Name,
25                                              const MCAsmInfo &MAI) const {
26
27  if (isUnique())
28    return false;
29
30  return MAI.shouldOmitSectionDirective(Name);
31}
32
33static void printName(raw_ostream &OS, StringRef Name) {
34  if (Name.find_first_not_of("0123456789_."
35                             "abcdefghijklmnopqrstuvwxyz"
36                             "ABCDEFGHIJKLMNOPQRSTUVWXYZ") == Name.npos) {
37    OS << Name;
38    return;
39  }
40  OS << '"';
41  for (const char *B = Name.begin(), *E = Name.end(); B < E; ++B) {
42    if (*B == '"') // Unquoted "
43      OS << "\\\"";
44    else if (*B != '\\') // Neither " or backslash
45      OS << *B;
46    else if (B + 1 == E) // Trailing backslash
47      OS << "\\\\";
48    else {
49      OS << B[0] << B[1]; // Quoted character
50      ++B;
51    }
52  }
53  OS << '"';
54}
55
56void MCSectionELF::PrintSwitchToSection(const MCAsmInfo &MAI,
57                                        raw_ostream &OS,
58                                        const MCExpr *Subsection) const {
59
60  if (ShouldOmitSectionDirective(SectionName, MAI)) {
61    OS << '\t' << getSectionName();
62    if (Subsection) {
63      OS << '\t';
64      Subsection->print(OS, &MAI);
65    }
66    OS << '\n';
67    return;
68  }
69
70  OS << "\t.section\t";
71  printName(OS, getSectionName());
72
73  // Handle the weird solaris syntax if desired.
74  if (MAI.usesSunStyleELFSectionSwitchSyntax() &&
75      !(Flags & ELF::SHF_MERGE)) {
76    if (Flags & ELF::SHF_ALLOC)
77      OS << ",#alloc";
78    if (Flags & ELF::SHF_EXECINSTR)
79      OS << ",#execinstr";
80    if (Flags & ELF::SHF_WRITE)
81      OS << ",#write";
82    if (Flags & ELF::SHF_EXCLUDE)
83      OS << ",#exclude";
84    if (Flags & ELF::SHF_TLS)
85      OS << ",#tls";
86    OS << '\n';
87    return;
88  }
89
90  OS << ",\"";
91  if (Flags & ELF::SHF_ALLOC)
92    OS << 'a';
93  if (Flags & ELF::SHF_EXCLUDE)
94    OS << 'e';
95  if (Flags & ELF::SHF_EXECINSTR)
96    OS << 'x';
97  if (Flags & ELF::SHF_GROUP)
98    OS << 'G';
99  if (Flags & ELF::SHF_WRITE)
100    OS << 'w';
101  if (Flags & ELF::SHF_MERGE)
102    OS << 'M';
103  if (Flags & ELF::SHF_STRINGS)
104    OS << 'S';
105  if (Flags & ELF::SHF_TLS)
106    OS << 'T';
107
108  // If there are target-specific flags, print them.
109  if (Flags & ELF::XCORE_SHF_CP_SECTION)
110    OS << 'c';
111  if (Flags & ELF::XCORE_SHF_DP_SECTION)
112    OS << 'd';
113
114  OS << '"';
115
116  OS << ',';
117
118  // If comment string is '@', e.g. as on ARM - use '%' instead
119  if (MAI.getCommentString()[0] == '@')
120    OS << '%';
121  else
122    OS << '@';
123
124  if (Type == ELF::SHT_INIT_ARRAY)
125    OS << "init_array";
126  else if (Type == ELF::SHT_FINI_ARRAY)
127    OS << "fini_array";
128  else if (Type == ELF::SHT_PREINIT_ARRAY)
129    OS << "preinit_array";
130  else if (Type == ELF::SHT_NOBITS)
131    OS << "nobits";
132  else if (Type == ELF::SHT_NOTE)
133    OS << "note";
134  else if (Type == ELF::SHT_PROGBITS)
135    OS << "progbits";
136  else if (Type == ELF::SHT_X86_64_UNWIND)
137    OS << "unwind";
138
139  if (EntrySize) {
140    assert(Flags & ELF::SHF_MERGE);
141    OS << "," << EntrySize;
142  }
143
144  if (Flags & ELF::SHF_GROUP) {
145    OS << ",";
146    printName(OS, Group->getName());
147    OS << ",comdat";
148  }
149
150  if (isUnique())
151    OS << ",unique," << UniqueID;
152
153  OS << '\n';
154
155  if (Subsection) {
156    OS << "\t.subsection\t";
157    Subsection->print(OS, &MAI);
158    OS << '\n';
159  }
160}
161
162bool MCSectionELF::UseCodeAlign() const {
163  return getFlags() & ELF::SHF_EXECINSTR;
164}
165
166bool MCSectionELF::isVirtualSection() const {
167  return getType() == ELF::SHT_NOBITS;
168}
169