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
18 using namespace llvm;
19
~MCSectionELF()20 MCSectionELF::~MCSectionELF() {} // anchor.
21
22 // Decides whether a '.section' directive
23 // should be printed before the section name.
ShouldOmitSectionDirective(StringRef Name,const MCAsmInfo & MAI) const24 bool MCSectionELF::ShouldOmitSectionDirective(StringRef Name,
25 const MCAsmInfo &MAI) const {
26
27 if (isUnique())
28 return false;
29
30 return MAI.shouldOmitSectionDirective(Name);
31 }
32
printName(raw_ostream & OS,StringRef Name)33 static 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
PrintSwitchToSection(const MCAsmInfo & MAI,raw_ostream & OS,const MCExpr * Subsection) const56 void 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
UseCodeAlign() const162 bool MCSectionELF::UseCodeAlign() const {
163 return getFlags() & ELF::SHF_EXECINSTR;
164 }
165
isVirtualSection() const166 bool MCSectionELF::isVirtualSection() const {
167 return getType() == ELF::SHT_NOBITS;
168 }
169