1//===- lib/MC/MCSectionELF.cpp - ELF 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/MCSectionELF.h"
10#include "llvm/BinaryFormat/ELF.h"
11#include "llvm/MC/MCAsmInfo.h"
12#include "llvm/MC/MCExpr.h"
13#include "llvm/Support/ErrorHandling.h"
14#include "llvm/Support/raw_ostream.h"
15#include "llvm/TargetParser/Triple.h"
16#include <cassert>
17
18using namespace llvm;
19
20// Decides whether a '.section' directive
21// should be printed before the section name.
22bool MCSectionELF::shouldOmitSectionDirective(StringRef Name,
23 const MCAsmInfo &MAI) const {
24 if (isUnique())
25 return false;
26
27 return MAI.shouldOmitSectionDirective(SectionName: Name);
28}
29
30static void printName(raw_ostream &OS, StringRef Name) {
31 if (Name.find_first_not_of(Chars: "0123456789_."
32 "abcdefghijklmnopqrstuvwxyz"
33 "ABCDEFGHIJKLMNOPQRSTUVWXYZ") == Name.npos) {
34 OS << Name;
35 return;
36 }
37 OS << '"';
38 for (const char *B = Name.begin(), *E = Name.end(); B < E; ++B) {
39 if (*B == '"') // Unquoted "
40 OS << "\\\"";
41 else if (*B != '\\') // Neither " or backslash
42 OS << *B;
43 else if (B + 1 == E) // Trailing backslash
44 OS << "\\\\";
45 else {
46 OS << B[0] << B[1]; // Quoted character
47 ++B;
48 }
49 }
50 OS << '"';
51}
52
53void MCSectionELF::printSwitchToSection(const MCAsmInfo &MAI, const Triple &T,
54 raw_ostream &OS,
55 uint32_t Subsection) const {
56 if (shouldOmitSectionDirective(Name: getName(), MAI)) {
57 OS << '\t' << getName();
58 if (Subsection)
59 OS << '\t' << Subsection;
60 OS << '\n';
61 return;
62 }
63
64 OS << "\t.section\t";
65 printName(OS, Name: getName());
66
67 // Handle the weird solaris syntax if desired.
68 if (MAI.usesSunStyleELFSectionSwitchSyntax() &&
69 !(Flags & ELF::SHF_MERGE)) {
70 if (Flags & ELF::SHF_ALLOC)
71 OS << ",#alloc";
72 if (Flags & ELF::SHF_EXECINSTR)
73 OS << ",#execinstr";
74 if (Flags & ELF::SHF_WRITE)
75 OS << ",#write";
76 if (Flags & ELF::SHF_EXCLUDE)
77 OS << ",#exclude";
78 if (Flags & ELF::SHF_TLS)
79 OS << ",#tls";
80 OS << '\n';
81 return;
82 }
83
84 OS << ",\"";
85 if (Flags & ELF::SHF_ALLOC)
86 OS << 'a';
87 if (Flags & ELF::SHF_EXCLUDE)
88 OS << 'e';
89 if (Flags & ELF::SHF_EXECINSTR)
90 OS << 'x';
91 if (Flags & ELF::SHF_WRITE)
92 OS << 'w';
93 if (Flags & ELF::SHF_MERGE)
94 OS << 'M';
95 if (Flags & ELF::SHF_STRINGS)
96 OS << 'S';
97 if (Flags & ELF::SHF_TLS)
98 OS << 'T';
99 if (Flags & ELF::SHF_LINK_ORDER)
100 OS << 'o';
101 if (Flags & ELF::SHF_GROUP)
102 OS << 'G';
103 if (Flags & ELF::SHF_GNU_RETAIN)
104 OS << 'R';
105
106 // If there are os-specific flags, print them.
107 if (T.isOSSolaris())
108 if (Flags & ELF::SHF_SUNW_NODISCARD)
109 OS << 'R';
110
111 // If there are target-specific flags, print them.
112 Triple::ArchType Arch = T.getArch();
113 if (Arch == Triple::xcore) {
114 if (Flags & ELF::XCORE_SHF_CP_SECTION)
115 OS << 'c';
116 if (Flags & ELF::XCORE_SHF_DP_SECTION)
117 OS << 'd';
118 } else if (T.isARM() || T.isThumb()) {
119 if (Flags & ELF::SHF_ARM_PURECODE)
120 OS << 'y';
121 } else if (Arch == Triple::hexagon) {
122 if (Flags & ELF::SHF_HEX_GPREL)
123 OS << 's';
124 } else if (Arch == Triple::x86_64) {
125 if (Flags & ELF::SHF_X86_64_LARGE)
126 OS << 'l';
127 }
128
129 OS << '"';
130
131 OS << ',';
132
133 // If comment string is '@', e.g. as on ARM - use '%' instead
134 if (MAI.getCommentString()[0] == '@')
135 OS << '%';
136 else
137 OS << '@';
138
139 if (Type == ELF::SHT_INIT_ARRAY)
140 OS << "init_array";
141 else if (Type == ELF::SHT_FINI_ARRAY)
142 OS << "fini_array";
143 else if (Type == ELF::SHT_PREINIT_ARRAY)
144 OS << "preinit_array";
145 else if (Type == ELF::SHT_NOBITS)
146 OS << "nobits";
147 else if (Type == ELF::SHT_NOTE)
148 OS << "note";
149 else if (Type == ELF::SHT_PROGBITS)
150 OS << "progbits";
151 else if (Type == ELF::SHT_X86_64_UNWIND)
152 OS << "unwind";
153 else if (Type == ELF::SHT_MIPS_DWARF)
154 // Print hex value of the flag while we do not have
155 // any standard symbolic representation of the flag.
156 OS << "0x7000001e";
157 else if (Type == ELF::SHT_LLVM_ODRTAB)
158 OS << "llvm_odrtab";
159 else if (Type == ELF::SHT_LLVM_LINKER_OPTIONS)
160 OS << "llvm_linker_options";
161 else if (Type == ELF::SHT_LLVM_CALL_GRAPH_PROFILE)
162 OS << "llvm_call_graph_profile";
163 else if (Type == ELF::SHT_LLVM_DEPENDENT_LIBRARIES)
164 OS << "llvm_dependent_libraries";
165 else if (Type == ELF::SHT_LLVM_SYMPART)
166 OS << "llvm_sympart";
167 else if (Type == ELF::SHT_LLVM_BB_ADDR_MAP)
168 OS << "llvm_bb_addr_map";
169 else if (Type == ELF::SHT_LLVM_BB_ADDR_MAP_V0)
170 OS << "llvm_bb_addr_map_v0";
171 else if (Type == ELF::SHT_LLVM_OFFLOADING)
172 OS << "llvm_offloading";
173 else if (Type == ELF::SHT_LLVM_LTO)
174 OS << "llvm_lto";
175 else
176 OS << "0x" << Twine::utohexstr(Val: Type);
177
178 if (EntrySize) {
179 assert(Flags & ELF::SHF_MERGE);
180 OS << "," << EntrySize;
181 }
182
183 if (Flags & ELF::SHF_LINK_ORDER) {
184 OS << ",";
185 if (LinkedToSym)
186 printName(OS, Name: LinkedToSym->getName());
187 else
188 OS << '0';
189 }
190
191 if (Flags & ELF::SHF_GROUP) {
192 OS << ",";
193 printName(OS, Name: Group.getPointer()->getName());
194 if (isComdat())
195 OS << ",comdat";
196 }
197
198 if (isUnique())
199 OS << ",unique," << UniqueID;
200
201 OS << '\n';
202
203 if (Subsection) {
204 OS << "\t.subsection\t" << Subsection;
205 OS << '\n';
206 }
207}
208
209bool MCSectionELF::useCodeAlign() const {
210 return getFlags() & ELF::SHF_EXECINSTR;
211}
212
213StringRef MCSectionELF::getVirtualSectionKind() const { return "SHT_NOBITS"; }
214