LLVM  15.0.0git
MCSectionELF.cpp
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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/ADT/Triple.h"
11 #include "llvm/BinaryFormat/ELF.h"
12 #include "llvm/MC/MCAsmInfo.h"
13 #include "llvm/MC/MCExpr.h"
16 #include <cassert>
17 
18 using namespace llvm;
19 
20 // Decides whether a '.section' directive
21 // should be printed before the section name.
23  const MCAsmInfo &MAI) const {
24  if (isUnique())
25  return false;
26 
27  return MAI.shouldOmitSectionDirective(Name);
28 }
29 
30 static void printName(raw_ostream &OS, StringRef Name) {
31  if (Name.find_first_not_of("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 
54  raw_ostream &OS,
55  const MCExpr *Subsection) const {
56  if (shouldOmitSectionDirective(getName(), MAI)) {
57  OS << '\t' << getName();
58  if (Subsection) {
59  OS << '\t';
60  Subsection->print(OS, &MAI);
61  }
62  OS << '\n';
63  return;
64  }
65 
66  OS << "\t.section\t";
67  printName(OS, getName());
68 
69  // Handle the weird solaris syntax if desired.
71  !(Flags & ELF::SHF_MERGE)) {
72  if (Flags & ELF::SHF_ALLOC)
73  OS << ",#alloc";
74  if (Flags & ELF::SHF_EXECINSTR)
75  OS << ",#execinstr";
76  if (Flags & ELF::SHF_WRITE)
77  OS << ",#write";
78  if (Flags & ELF::SHF_EXCLUDE)
79  OS << ",#exclude";
80  if (Flags & ELF::SHF_TLS)
81  OS << ",#tls";
82  OS << '\n';
83  return;
84  }
85 
86  OS << ",\"";
87  if (Flags & ELF::SHF_ALLOC)
88  OS << 'a';
89  if (Flags & ELF::SHF_EXCLUDE)
90  OS << 'e';
91  if (Flags & ELF::SHF_EXECINSTR)
92  OS << 'x';
93  if (Flags & ELF::SHF_GROUP)
94  OS << 'G';
95  if (Flags & ELF::SHF_WRITE)
96  OS << 'w';
97  if (Flags & ELF::SHF_MERGE)
98  OS << 'M';
99  if (Flags & ELF::SHF_STRINGS)
100  OS << 'S';
101  if (Flags & ELF::SHF_TLS)
102  OS << 'T';
103  if (Flags & ELF::SHF_LINK_ORDER)
104  OS << 'o';
105  if (Flags & ELF::SHF_GNU_RETAIN)
106  OS << 'R';
107 
108  // If there are os-specific flags, print them.
109  if (T.isOSSolaris())
110  if (Flags & ELF::SHF_SUNW_NODISCARD)
111  OS << 'R';
112 
113  // If there are target-specific flags, print them.
114  Triple::ArchType Arch = T.getArch();
115  if (Arch == Triple::xcore) {
116  if (Flags & ELF::XCORE_SHF_CP_SECTION)
117  OS << 'c';
118  if (Flags & ELF::XCORE_SHF_DP_SECTION)
119  OS << 'd';
120  } else if (T.isARM() || T.isThumb()) {
121  if (Flags & ELF::SHF_ARM_PURECODE)
122  OS << 'y';
123  } else if (Arch == Triple::hexagon) {
124  if (Flags & ELF::SHF_HEX_GPREL)
125  OS << 's';
126  }
127 
128  OS << '"';
129 
130  OS << ',';
131 
132  // If comment string is '@', e.g. as on ARM - use '%' instead
133  if (MAI.getCommentString()[0] == '@')
134  OS << '%';
135  else
136  OS << '@';
137 
138  if (Type == ELF::SHT_INIT_ARRAY)
139  OS << "init_array";
140  else if (Type == ELF::SHT_FINI_ARRAY)
141  OS << "fini_array";
142  else if (Type == ELF::SHT_PREINIT_ARRAY)
143  OS << "preinit_array";
144  else if (Type == ELF::SHT_NOBITS)
145  OS << "nobits";
146  else if (Type == ELF::SHT_NOTE)
147  OS << "note";
148  else if (Type == ELF::SHT_PROGBITS)
149  OS << "progbits";
150  else if (Type == ELF::SHT_X86_64_UNWIND)
151  OS << "unwind";
152  else if (Type == ELF::SHT_MIPS_DWARF)
153  // Print hex value of the flag while we do not have
154  // any standard symbolic representation of the flag.
155  OS << "0x7000001e";
156  else if (Type == ELF::SHT_LLVM_ODRTAB)
157  OS << "llvm_odrtab";
159  OS << "llvm_linker_options";
161  OS << "llvm_call_graph_profile";
163  OS << "llvm_dependent_libraries";
164  else if (Type == ELF::SHT_LLVM_SYMPART)
165  OS << "llvm_sympart";
166  else if (Type == ELF::SHT_LLVM_BB_ADDR_MAP)
167  OS << "llvm_bb_addr_map";
168  else
169  report_fatal_error("unsupported type 0x" + Twine::utohexstr(Type) +
170  " for section " + getName());
171 
172  if (EntrySize) {
173  assert(Flags & ELF::SHF_MERGE);
174  OS << "," << EntrySize;
175  }
176 
177  if (Flags & ELF::SHF_GROUP) {
178  OS << ",";
179  printName(OS, Group.getPointer()->getName());
180  if (isComdat())
181  OS << ",comdat";
182  }
183 
184  if (Flags & ELF::SHF_LINK_ORDER) {
185  OS << ",";
186  if (LinkedToSym)
187  printName(OS, LinkedToSym->getName());
188  else
189  OS << '0';
190  }
191 
192  if (isUnique())
193  OS << ",unique," << UniqueID;
194 
195  OS << '\n';
196 
197  if (Subsection) {
198  OS << "\t.subsection\t";
199  Subsection->print(OS, &MAI);
200  OS << '\n';
201  }
202 }
203 
205  return getFlags() & ELF::SHF_EXECINSTR;
206 }
207 
209  return getType() == ELF::SHT_NOBITS;
210 }
211 
212 StringRef MCSectionELF::getVirtualSectionKind() const { return "SHT_NOBITS"; }
llvm::ELF::SHF_EXECINSTR
@ SHF_EXECINSTR
Definition: ELF.h:1029
llvm::MCSection::Name
StringRef Name
Definition: MCSection.h:112
llvm::MCAsmInfo::usesSunStyleELFSectionSwitchSyntax
bool usesSunStyleELFSectionSwitchSyntax() const
Definition: MCAsmInfo.h:615
llvm::ELF::SHF_EXCLUDE
@ SHF_EXCLUDE
Definition: ELF.h:1060
llvm
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:17
llvm::MCAsmInfo::getCommentString
StringRef getCommentString() const
Definition: MCAsmInfo.h:653
llvm::ELF::SHT_LLVM_DEPENDENT_LIBRARIES
@ SHT_LLVM_DEPENDENT_LIBRARIES
Definition: ELF.h:974
llvm::MCSectionELF::printSwitchToSection
void printSwitchToSection(const MCAsmInfo &MAI, const Triple &T, raw_ostream &OS, const MCExpr *Subsection) const override
Definition: MCSectionELF.cpp:53
llvm::MCAsmInfo
This class is intended to be used as a base class for asm properties and features specific to the tar...
Definition: MCAsmInfo.h:56
MCSectionELF.h
llvm::ELF::SHF_STRINGS
@ SHF_STRINGS
Definition: ELF.h:1035
ErrorHandling.h
llvm::Triple
Triple - Helper class for working with autoconf configuration names.
Definition: Triple.h:44
llvm::ELF::SHF_SUNW_NODISCARD
@ SHF_SUNW_NODISCARD
Definition: ELF.h:1067
llvm::ELF::SHT_LLVM_ODRTAB
@ SHT_LLVM_ODRTAB
Definition: ELF.h:970
llvm::Type
The instances of the Type class are immutable: once they are created, they are never changed.
Definition: Type.h:45
T
#define T
Definition: Mips16ISelLowering.cpp:341
llvm::Triple::hexagon
@ hexagon
Definition: Triple.h:60
llvm::ELF::SHF_ALLOC
@ SHF_ALLOC
Definition: ELF.h:1026
llvm::ELF::SHT_INIT_ARRAY
@ SHT_INIT_ARRAY
Definition: ELF.h:957
llvm::ELF::SHF_LINK_ORDER
@ SHF_LINK_ORDER
Definition: ELF.h:1041
llvm::ELF::SHT_LLVM_BB_ADDR_MAP
@ SHT_LLVM_BB_ADDR_MAP
Definition: ELF.h:979
llvm::ELF::XCORE_SHF_DP_SECTION
@ XCORE_SHF_DP_SECTION
All sections with the "d" flag are grouped together by the linker to form the data section and the dp...
Definition: ELF.h:1075
llvm::MCAsmInfo::shouldOmitSectionDirective
virtual bool shouldOmitSectionDirective(StringRef SectionName) const
Return true if the .section directive should be omitted when emitting SectionName.
Definition: MCAsmInfo.cpp:137
llvm::ELF::SHF_MERGE
@ SHF_MERGE
Definition: ELF.h:1032
ELF.h
llvm::Triple::ArchType
ArchType
Definition: Triple.h:46
E
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
printName
static void printName(raw_ostream &OS, StringRef Name)
Definition: MCSectionELF.cpp:30
llvm::MCSectionELF::isUnique
bool isUnique() const
Definition: MCSectionELF.h:86
llvm::ELF::SHT_LLVM_CALL_GRAPH_PROFILE
@ SHT_LLVM_CALL_GRAPH_PROFILE
Definition: ELF.h:980
B
static GCRegistry::Add< OcamlGC > B("ocaml", "ocaml 3.10-compatible GC")
llvm::MCSectionELF::isVirtualSection
bool isVirtualSection() const override
Check whether this section is "virtual", that is has no actual object file contents.
Definition: MCSectionELF.cpp:208
llvm::Triple::xcore
@ xcore
Definition: Triple.h:87
llvm::report_fatal_error
void report_fatal_error(Error Err, bool gen_crash_diag=true)
Report a serious error, calling any installed error handler.
Definition: Error.cpp:143
llvm::ELF::SHT_LLVM_LINKER_OPTIONS
@ SHT_LLVM_LINKER_OPTIONS
Definition: ELF.h:971
llvm::raw_ostream
This class implements an extremely fast bulk output stream that can only output to a stream.
Definition: raw_ostream.h:54
llvm::MCSectionELF::shouldOmitSectionDirective
bool shouldOmitSectionDirective(StringRef Name, const MCAsmInfo &MAI) const
Decides whether a '.section' directive should be printed before the section name.
Definition: MCSectionELF.cpp:22
llvm::MCSymbol::getName
StringRef getName() const
getName - Get the symbol name.
Definition: MCSymbol.h:198
llvm::MCSectionELF::isComdat
bool isComdat() const
Definition: MCSectionELF.h:77
llvm::ELF::SHF_HEX_GPREL
@ SHF_HEX_GPREL
Definition: ELF.h:1093
llvm::ELF::SHF_GNU_RETAIN
@ SHF_GNU_RETAIN
Definition: ELF.h:1057
llvm::Twine::utohexstr
static Twine utohexstr(const uint64_t &Val)
Definition: Twine.h:408
llvm::ELF::SHF_ARM_PURECODE
@ SHF_ARM_PURECODE
Definition: ELF.h:1121
llvm::ELF::SHT_NOBITS
@ SHT_NOBITS
Definition: ELF.h:953
assert
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
llvm::ELF::SHF_WRITE
@ SHF_WRITE
Definition: ELF.h:1023
llvm::ELF::SHF_GROUP
@ SHF_GROUP
Definition: ELF.h:1048
llvm::ELF::SHF_TLS
@ SHF_TLS
Definition: ELF.h:1051
Triple.h
llvm::MCSectionELF::getFlags
unsigned getFlags() const
Definition: MCSectionELF.h:73
llvm::MCSectionELF::useCodeAlign
bool useCodeAlign() const override
Return true if a .align directive should use "optimized nops" to fill instead of 0s.
Definition: MCSectionELF.cpp:204
MCAsmInfo.h
llvm::StringRef
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:58
llvm::ELF::SHT_MIPS_DWARF
@ SHT_MIPS_DWARF
Definition: ELF.h:1006
llvm::MCSectionELF::getVirtualSectionKind
StringRef getVirtualSectionKind() const override
Definition: MCSectionELF.cpp:212
llvm::MCSection::getName
StringRef getName() const
Definition: MCSection.h:123
llvm::GraphProgram::Name
Name
Definition: GraphWriter.h:50
llvm::ELF::SHT_PROGBITS
@ SHT_PROGBITS
Definition: ELF.h:946
llvm::ELF::SHT_FINI_ARRAY
@ SHT_FINI_ARRAY
Definition: ELF.h:958
llvm::MCExpr::print
void print(raw_ostream &OS, const MCAsmInfo *MAI, bool InParens=false) const
Definition: MCExpr.cpp:41
llvm::ELF::SHT_LLVM_SYMPART
@ SHT_LLVM_SYMPART
Definition: ELF.h:976
llvm::ELF::SHT_X86_64_UNWIND
@ SHT_X86_64_UNWIND
Definition: ELF.h:1002
raw_ostream.h
MCExpr.h
llvm::MCExpr
Base class for the full range of assembler expressions which are needed for parsing.
Definition: MCExpr.h:35
llvm::MCSectionELF::getType
unsigned getType() const
Definition: MCSectionELF.h:72
llvm::ELF::XCORE_SHF_CP_SECTION
@ XCORE_SHF_CP_SECTION
All sections with the "c" flag are grouped together by the linker to form the constant pool and the c...
Definition: ELF.h:1080
llvm::ELF::SHT_PREINIT_ARRAY
@ SHT_PREINIT_ARRAY
Definition: ELF.h:959
llvm::ELF::SHT_NOTE
@ SHT_NOTE
Definition: ELF.h:952