Include version string into ".comment" section.

[ruiu]

Summary

This patch adds a ".comment" section to an output. The comment
section contains the linker's version string. You can now
find out whether a binary is created by LLD or not using objdump
command like this.

$ objdump -s -j .comment foo

foo:     file format elf64-x86-64

Contents of section .comment:
 0000 00474343 3a202855 62756e74 7520342e  .GCC: (Ubuntu 4.
 0010 382e342d 32756275 6e747531 7e31342e  8.4-2ubuntu1~14.
 ...
 00c0 766d2f74 72756e6b 20323835 38343629  vm/trunk 285846)
 00d0 004c696e 6b65723a 204c4c44 20342e30  .Linker: LLD 4.0
 00e0 2e302028 7472756e 6b203238 36343036  .0 (trunk 286406
 00f0 2900                                 ).

Compilers emits .comment section as well, so the output contains
both compiler and linker information.

Alternative considered:

I first tried to add a SHT_NOTE section because GNU gold does that.
A NOTE section starts with a header which contains content type.
It turned out that ld.gold sets type NT_GNU_GOLD_VERSION to their
NOTE section. So the NOTE type is only for GNU gold (surprise!)

Next, I tried to create ".linker-version" section. However, it seems
that reusing the existing ".comment" section is better because 1)
other tools already know about .comment section and is able to strip
it and 2) the result contans not only linker info but also compiler
info.

[• rafael]

LGTM.Thanks!

[davide]

lg

ELF/SyntheticSections.h

 class BuildIdHexstring final : public BuildIdSection<ELFT> {
 public:
   BuildIdHexstring();
   void writeBuildId(llvm::MutableArrayRef<uint8_t>) override;
 };
 
 template <class ELFT> InputSection<ELFT> *createCommonSection();
 template <class ELFT> InputSection<ELFT> *createInterpSection();
+template <class ELFT> MergeInputSection<ELFT> *createCommentSection();
 
 // Linker generated sections which can be used as inputs.
 template <class ELFT> struct In {
   static BuildIdSection<ELFT> *BuildId;
   static InputSection<ELFT> *Common;
   static InputSection<ELFT> *Interp;
   static MipsAbiFlagsSection<ELFT> *MipsAbiFlags;
   static MipsOptionsSection<ELFT> *MipsOptions;

ELF/SyntheticSections.cpp

 #include "InputFiles.h"
 #include "Memory.h"
 #include "OutputSections.h"
 #include "Strings.h"
 #include "SymbolTable.h"
 #include "Target.h"
 #include "Writer.h"
 
+#include "lld/Config/Version.h"
 #include "lld/Core/Parallel.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/MD5.h"
 #include "llvm/Support/RandomNumberGenerator.h"
 #include "llvm/Support/SHA1.h"
 #include "llvm/Support/xxhash.h"
+#include <cstdlib>
 
 using namespace llvm;
 using namespace llvm::ELF;
 using namespace llvm::object;
 using namespace llvm::support;
 using namespace llvm::support::endian;
 
 using namespace lld;
for (DefinedCommon *Sym : Syms) {
     Sym->Offset = Size;
     Size += Sym->Size;
   }
   Ret->Alignment = Alignment;
   Ret->Data = makeArrayRef<uint8_t>(nullptr, Size);
   return Ret;
 }
 
+// Returns a LLD version string.
+static ArrayRef<uint8_t> getVersion() {
+  // Check LLD_VERSION first for ease of testing.
+  // You can get consitent output by using the environment variable.
+  // It is usually not set.
+  StringRef S = getenv("LLD_VERSION");
+  if (S.empty())
+    S = Saver.save(Twine("Linker: ") + getLLDVersion());
+
+  // +1 to include the terminating '\0'.
+  return {(const uint8_t *)S.data(), S.size() + 1};
+};
+
+// Creates a .comment section containing LLD version info.
+// With this feature, you can identify LLD-generated binaries easily
+// by "objdump -s -j .comment <file>".
+// The returned object is a mergeable string section.
+template <class ELFT> MergeInputSection<ELFT> *elf::createCommentSection() {
+  typename ELFT::Shdr Hdr = {};
+  Hdr.sh_flags = SHF_MERGE | SHF_STRINGS;
+  Hdr.sh_type = SHT_PROGBITS;
+  Hdr.sh_entsize = 1;
+  Hdr.sh_link = 0;
+  Hdr.sh_info = 0;
+  Hdr.sh_addralign = 1;
+
+  auto *Ret = make<MergeInputSection<ELFT>>(/*file=*/nullptr, &Hdr, ".comment");
+  Ret->Data = getVersion();
+  Ret->splitIntoPieces();
+  return Ret;
+}
+
 // Iterate over sections of the specified type. For each section call
 // provided function. After that "kill" the section by turning off
 // "Live" flag, so that they won't be included in the final output.
 template <class ELFT>
 static void iterateSectionContents(
     uint32_t Type,
     std::function<void(elf::ObjectFile<ELFT> *, ArrayRef<uint8_t>)> F) {
   for (InputSectionBase<ELFT> *Sec : Symtab<ELFT>::X->Sections) {

 template InputSection<ELF64LE> *elf::createCommonSection();
 template InputSection<ELF64BE> *elf::createCommonSection();
 
 template InputSection<ELF32LE> *elf::createInterpSection();
 template InputSection<ELF32BE> *elf::createInterpSection();
 template InputSection<ELF64LE> *elf::createInterpSection();
 template InputSection<ELF64BE> *elf::createInterpSection();
 
+template MergeInputSection<ELF32LE> *elf::createCommentSection();
+template MergeInputSection<ELF32BE> *elf::createCommentSection();
+template MergeInputSection<ELF64LE> *elf::createCommentSection();
+template MergeInputSection<ELF64BE> *elf::createCommentSection();
+
 template class elf::MipsAbiFlagsSection<ELF32LE>;
 template class elf::MipsAbiFlagsSection<ELF32BE>;
 template class elf::MipsAbiFlagsSection<ELF64LE>;
 template class elf::MipsAbiFlagsSection<ELF64BE>;
 
 template class elf::MipsOptionsSection<ELF32LE>;
 template class elf::MipsOptionsSection<ELF32BE>;
 template class elf::MipsOptionsSection<ELF64LE>;

ELF/Writer.cpp

Out<ELFT>::MipsRldMap = make<OutputSection<ELFT>>(".rld_map", SHT_PROGBITS,
                                                       SHF_ALLOC | SHF_WRITE);
     Out<ELFT>::MipsRldMap->Size = sizeof(uintX_t);
     Out<ELFT>::MipsRldMap->updateAlignment(sizeof(uintX_t));
   }
   if (!Config->VersionDefinitions.empty())
     Out<ELFT>::VerDef = make<VersionDefinitionSection<ELFT>>();
 
   // Initialize linker generated sections
+  Symtab<ELFT>::X->Sections.push_back(createCommentSection<ELFT>());
+
   if (Config->BuildId == BuildIdKind::Fast)
     In<ELFT>::BuildId = make<BuildIdFastHash<ELFT>>();
   else if (Config->BuildId == BuildIdKind::Md5)
     In<ELFT>::BuildId = make<BuildIdMd5<ELFT>>();
   else if (Config->BuildId == BuildIdKind::Sha1)
     In<ELFT>::BuildId = make<BuildIdSha1<ELFT>>();
   else if (Config->BuildId == BuildIdKind::Uuid)
     In<ELFT>::BuildId = make<BuildIdUuid<ELFT>>();

test/ELF/aarch64-gnu-ifunc.s

 // CHECK-NEXT:  Name: .rela.plt
 // CHECK-NEXT:  Type: SHT_RELA
 // CHECK-NEXT:  Flags [
 // CHECK-NEXT:    SHF_ALLOC
 // CHECK-NEXT:  ]
 // CHECK-NEXT:  Address: [[RELA:.*]]
 // CHECK-NEXT:  Offset: 0x158
 // CHECK-NEXT:  Size: 48
-// CHECK-NEXT:  Link: 5
+// CHECK-NEXT:  Link: 6
 // CHECK-NEXT:  Info: 0
 // CHECK-NEXT:  AddressAlignment: 8
 // CHECK-NEXT:  EntrySize: 24
 // CHECK-NEXT: }
 // CHECK:      Relocations [
 // CHECK-NEXT:   Section ({{.*}}) .rela.plt {
 // CHECK-NEXT:     0x30018 R_AARCH64_IRELATIVE
 // CHECK-NEXT:     0x30020 R_AARCH64_IRELATIVE

test/ELF/basic-aarch64.s

 # CHECK-NEXT:     ABIVersion: 0
 # CHECK-NEXT:     Unused: (00 00 00 00 00 00 00)
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Type: Executable (0x2)
 # CHECK-NEXT:   Machine: EM_AARCH64 (0xB7)
 # CHECK-NEXT:   Version: 1
 # CHECK-NEXT:   Entry: [[ENTRY:0x[0-9A-F]+]]
 # CHECK-NEXT:   ProgramHeaderOffset: 0x40
-# CHECK-NEXT:   SectionHeaderOffset: 0x10088
+# CHECK-NEXT:   SectionHeaderOffset: 0x10098
 # CHECK-NEXT:   Flags [ (0x0)
 # CHECK-NEXT:   ]
 # CHECK-NEXT:   HeaderSize: 64
 # CHECK-NEXT:   ProgramHeaderEntrySize: 56
 # CHECK-NEXT:   ProgramHeaderCount: 4
 # CHECK-NEXT:   SectionHeaderEntrySize: 64
-# CHECK-NEXT:   SectionHeaderCount: 5
-# CHECK-NEXT:   StringTableSectionIndex: 3
+# CHECK-NEXT:   SectionHeaderCount: 6
+# CHECK-NEXT:   StringTableSectionIndex: 4
 # CHECK-NEXT: }
 # CHECK-NEXT: Sections [
 # CHECK-NEXT:   Section {
 # CHECK-NEXT:     Index: 0
 # CHECK-NEXT:     Name:  (0)
 # CHECK-NEXT:     Type: SHT_NULL (0x0)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]

 # CHECK-NEXT:     Size: 12
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
 # CHECK-NEXT:     AddressAlignment: 4
 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
 # CHECK-NEXT:     Index: 2
+# CHECK-NEXT:     Name: .comment
+# CHECK-NEXT:     Type: SHT_PROGBITS (0x1)
+# CHECK-NEXT:     Flags [ (0x30)
+# CHECK-NEXT:       SHF_MERGE (0x10)
+# CHECK-NEXT:       SHF_STRINGS (0x20)
+# CHECK-NEXT:     ]
+# CHECK-NEXT:     Address: 0x0
+# CHECK-NEXT:     Offset: 0x1000C
+# CHECK-NEXT:     Size: 8
+# CHECK-NEXT:     Link: 0
+# CHECK-NEXT:     Info: 0
+# CHECK-NEXT:     AddressAlignment: 1
+# CHECK-NEXT:     EntrySize: 1
+# CHECK-NEXT:   }
+# CHECK-NEXT:   Section {
+# CHECK-NEXT:     Index: 3
 # CHECK-NEXT:     Name: .symtab
 # CHECK-NEXT:     Type: SHT_SYMTAB (0x2)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x10010
+# CHECK-NEXT:     Offset: 0x10018
 # CHECK-NEXT:     Size: 72
-# CHECK-NEXT:     Link: 4
+# CHECK-NEXT:     Link: 5
 # CHECK-NEXT:     Info: 2
 # CHECK-NEXT:     AddressAlignment: 8
 # CHECK-NEXT:     EntrySize: 24
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
-# CHECK-NEXT:     Index: 3
+# CHECK-NEXT:     Index: 4
 # CHECK-NEXT:     Name: .shstrtab
 # CHECK-NEXT:     Type: SHT_STRTAB (0x3)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x10058
-# CHECK-NEXT:     Size: 33
+# CHECK-NEXT:     Offset: 0x10060
+# CHECK-NEXT:     Size: 42
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
 # CHECK-NEXT:     AddressAlignment: 1
 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
-# CHECK-NEXT:     Index: 4
+# CHECK-NEXT:     Index: 5
 # CHECK-NEXT:     Name: .strtab
 # CHECK-NEXT:     Type: SHT_STRTAB (0x3)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x10079
+# CHECK-NEXT:     Offset: 0x1008A
 # CHECK-NEXT:     Size: 13
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
 # CHECK-NEXT:     AddressAlignment: 1
 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:   }
 # CHECK-NEXT: ]
 # CHECK-NEXT: Symbols [

test/ELF/basic-mips.s

 # CHECK-NEXT:     ABIVersion: 0
 # CHECK-NEXT:     Unused: (00 00 00 00 00 00 00)
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Type: Executable (0x2)
 # CHECK-NEXT:   Machine: EM_MIPS (0x8)
 # CHECK-NEXT:   Version: 1
 # CHECK-NEXT:   Entry: 0x20000
 # CHECK-NEXT:   ProgramHeaderOffset: 0x34
-# CHECK-NEXT:   SectionHeaderOffset: 0x30088
+# CHECK-NEXT:   SectionHeaderOffset: 0x30098
 # CHECK-NEXT:   Flags [
 # CHECK-NEXT:     EF_MIPS_ABI_O32
 # CHECK-NEXT:     EF_MIPS_ARCH_32
 # CHECK-NEXT:     EF_MIPS_CPIC
 # CHECK-NEXT:   ]
 # CHECK-NEXT:   HeaderSize: 52
 # CHECK-NEXT:   ProgramHeaderEntrySize: 32
 # CHECK-NEXT:   ProgramHeaderCount: 6
 # CHECK-NEXT:   SectionHeaderEntrySize: 40
-# CHECK-NEXT:   SectionHeaderCount: 10
-# CHECK-NEXT:   StringTableSectionIndex: 8
+# CHECK-NEXT:   SectionHeaderCount: 11
+# CHECK-NEXT:   StringTableSectionIndex: 9
 # CHECK-NEXT: }
 # CHECK-NEXT: Sections [
 # CHECK-NEXT:   Section {
 # CHECK-NEXT:     Index: 0
 # CHECK-NEXT:     Name:  (0)
 # CHECK-NEXT:     Type: SHT_NULL (0x0)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]

 # CHECK-NEXT:     Size: 0
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
 # CHECK-NEXT:     AddressAlignment: 16
 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
 # CHECK-NEXT:     Index: 7
+# CHECK-NEXT:     Name: .comment
+# CHECK-NEXT:     Type: SHT_PROGBITS (0x1)
+# CHECK-NEXT:     Flags [ (0x30)
+# CHECK-NEXT:       SHF_MERGE (0x10)
+# CHECK-NEXT:       SHF_STRINGS (0x20)
+# CHECK-NEXT:     ]
+# CHECK-NEXT:     Address: 0x0
+# CHECK-NEXT:     Offset: 0x30000
+# CHECK-NEXT:     Size: 8
+# CHECK-NEXT:     Link: 0
+# CHECK-NEXT:     Info: 0
+# CHECK-NEXT:     AddressAlignment: 1
+# CHECK-NEXT:     EntrySize: 1
+# CHECK-NEXT:   }
+# CHECK-NEXT:   Section {
+# CHECK-NEXT:     Index: 8
 # CHECK-NEXT:     Name: .symtab
 # CHECK-NEXT:     Type: SHT_SYMTAB (0x2)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x30000
+# CHECK-NEXT:     Offset: 0x30008
 # CHECK-NEXT:     Size: 48
-# CHECK-NEXT:     Link: 9
+# CHECK-NEXT:     Link: 10
 # CHECK-NEXT:     Info: 1
 # CHECK-NEXT:     AddressAlignment: 4
 # CHECK-NEXT:     EntrySize: 16
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
-# CHECK-NEXT:     Index: 8
+# CHECK-NEXT:     Index: 9
 # CHECK-NEXT:     Name: .shstrtab
 # CHECK-NEXT:     Type: SHT_STRTAB (0x3)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x30030
-# CHECK-NEXT:     Size: 73
+# CHECK-NEXT:     Offset: 0x30038
+# CHECK-NEXT:     Size: 82
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
 # CHECK-NEXT:     AddressAlignment: 1
 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
-# CHECK-NEXT:     Index: 9
+# CHECK-NEXT:     Index: 10
 # CHECK-NEXT:     Name: .strtab
 # CHECK-NEXT:     Type: SHT_STRTAB (0x3)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x30079
+# CHECK-NEXT:     Offset: 0x3008A
 # CHECK-NEXT:     Size: 13
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
 # CHECK-NEXT:     AddressAlignment: 1
 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:   }
 # CHECK-NEXT: ]
 # CHECK-NEXT: Symbols [

test/ELF/basic-ppc.s

 // CHECK-NEXT:     ABIVersion: 0
 // CHECK-NEXT:     Unused: (00 00 00 00 00 00 00)
 // CHECK-NEXT:   }
 // CHECK-NEXT:   Type: SharedObject (0x3)
 // CHECK-NEXT:   Machine: EM_PPC (0x14)
 // CHECK-NEXT:   Version: 1
 // CHECK-NEXT:   Entry: 0x0
 // CHECK-NEXT:   ProgramHeaderOffset: 0x34
-// CHECK-NEXT:   SectionHeaderOffset: 0x209C
+// CHECK-NEXT:   SectionHeaderOffset: 0x20AC
 // CHECK-NEXT:   Flags [ (0x0)
 // CHECK-NEXT:   ]
 // CHECK-NEXT:   HeaderSize: 52
 // CHECK-NEXT:   ProgramHeaderEntrySize: 32
 // CHECK-NEXT:   ProgramHeaderCount: 7
 // CHECK-NEXT:   SectionHeaderEntrySize: 40
-// CHECK-NEXT:   SectionHeaderCount: 9
-// CHECK-NEXT:   StringTableSectionIndex: 7
+// CHECK-NEXT:   SectionHeaderCount: 10
+// CHECK-NEXT:   StringTableSectionIndex: 8
 // CHECK-NEXT: }
 // CHECK-NEXT: Sections [
 // CHECK-NEXT:   Section {
 // CHECK-NEXT:     Index: 0
 // CHECK-NEXT:     Name:  (0)
 // CHECK-NEXT:     Type: SHT_NULL (0x0)
 // CHECK-NEXT:     Flags [ (0x0)
 // CHECK-NEXT:     ]

 // CHECK-NEXT:     SectionData (
 // CHECK-NEXT:       0000: 00000006 00000114 0000000B 00000010  |................|
 // CHECK-NEXT:       0010: 00000005 00000134 0000000A 00000001  |.......4........|
 // CHECK-NEXT:       0020: 00000004 00000124 00000000 00000000  |.......$........|
 // CHECK-NEXT:     )
 // CHECK-NEXT:   }
 // CHECK-NEXT:   Section {
 // CHECK-NEXT:     Index: 6
+// CHECK-NEXT:     Name: .comment
+// CHECK-NEXT:     Type: SHT_PROGBITS (0x1)
+// CHECK-NEXT:     Flags [ (0x30)
+// CHECK-NEXT:       SHF_MERGE (0x10)
+// CHECK-NEXT:       SHF_STRINGS (0x20)
+// CHECK-NEXT:     ]
+// CHECK-NEXT:     Address: 0x0
+// CHECK-NEXT:     Offset: 0x2030
+// CHECK-NEXT:     Size: 8
+// CHECK-NEXT:     Link: 0
+// CHECK-NEXT:     Info: 0
+// CHECK-NEXT:     AddressAlignment: 1
+// CHECK-NEXT:     EntrySize: 1
+// CHECK-NEXT:     SectionData (
+// CHECK-NEXT:       0000: 4C4C4420 312E3000 |LLD 1.0.|
+// CHECK-NEXT:     )
+// CHECK-NEXT:   }
+// CHECK-NEXT:   Section {
+// CHECK-NEXT:     Index: 7
 // CHECK-NEXT:     Name: .symtab
 // CHECK-NEXT:     Type: SHT_SYMTAB (0x2)
 // CHECK-NEXT:     Flags [ (0x0)
 // CHECK-NEXT:     ]
 // CHECK-NEXT:     Address: 0x0
-// CHECK-NEXT:     Offset: 0x2030
+// CHECK-NEXT:     Offset: 0x2038
 // CHECK-NEXT:     Size: 32
-// CHECK-NEXT:     Link: 8
+// CHECK-NEXT:     Link: 9
 // CHECK-NEXT:     Info: 1
 // CHECK-NEXT:     AddressAlignment: 4
 // CHECK-NEXT:     EntrySize: 16
 // CHECK-NEXT:     SectionData (
 // CHECK-NEXT:       0000: 00000000 00000000 00000000 00000000  |................|
 // CHECK-NEXT:       0010: 00000001 00002000 00000000 00020005  |...... .........|
 // CHECK-NEXT:     )
 // CHECK-NEXT:   }
 // CHECK-NEXT:   Section {
-// CHECK-NEXT:     Index: 7
+// CHECK-NEXT:     Index: 8
 // CHECK-NEXT:     Name: .shstrtab
 // CHECK-NEXT:     Type: SHT_STRTAB (0x3)
 // CHECK-NEXT:     Flags [ (0x0)
 // CHECK-NEXT:     ]
 // CHECK-NEXT:     Address: 0x0
-// CHECK-NEXT:     Offset: 0x2050
-// CHECK-NEXT:     Size: 64
+// CHECK-NEXT:     Offset: 0x2058
+// CHECK-NEXT:     Size: 73
 // CHECK-NEXT:     Link: 0
 // CHECK-NEXT:     Info: 0
 // CHECK-NEXT:     AddressAlignment: 1
 // CHECK-NEXT:     EntrySize: 0
 // CHECK-NEXT:     SectionData (
 // CHECK-NEXT:       0000: 002E6479 6E73796D 002E6861 7368002E  |..dynsym..hash..|
 // CHECK-NEXT:       0010: 64796E73 7472002E 74657874 002E6479  |dynstr..text..dy|
-// CHECK-NEXT:       0020: 6E616D69 63002E73 796D7461 62002E73  |namic..symtab..s|
-// CHECK-NEXT:       0030: 68737472 74616200 2E737472 74616200  |hstrtab..strtab.|
+// CHECK-NEXT:       0020: 6E616D69 63002E63 6F6D6D65 6E74002E  |namic..comment..|
+// CHECK-NEXT:       0030: 73796D74 6162002E 73687374 72746162  |symtab..shstrtab|
+// CHECK-NEXT:       0040: 002E7374 72746162 00                 |..strtab.|
 // CHECK-NEXT:     )
 // CHECK-NEXT:   }
 // CHECK-NEXT:   Section {
-// CHECK-NEXT:     Index: 8
+// CHECK-NEXT:     Index: 9
 // CHECK-NEXT:     Name: .strtab
 // CHECK-NEXT:     Type: SHT_STRTAB (0x3)
 // CHECK-NEXT:     Flags [ (0x0)
 // CHECK-NEXT:     ]
 // CHECK-NEXT:     Address: 0x0
-// CHECK-NEXT:     Offset: 0x2090
+// CHECK-NEXT:     Offset: 0x20A1
 // CHECK-NEXT:     Size: 1
 // CHECK-NEXT:     Link: 0
 // CHECK-NEXT:     Info: 0
 // CHECK-NEXT:     AddressAlignment: 1
 // CHECK-NEXT:     EntrySize: 0
 // CHECK-NEXT:     SectionData (
 // CHECK-NEXT:       0000: 005F4459 4E414D49 4300               |._DYNAMIC.|
 // CHECK-NEXT:     )

test/ELF/basic.s

 # CHECK-NEXT:     ABIVersion: 0
 # CHECK-NEXT:     Unused: (00 00 00 00 00 00 00)
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Type: Executable (0x2)
 # CHECK-NEXT:   Machine: EM_X86_64 (0x3E)
 # CHECK-NEXT:   Version: 1
 # CHECK-NEXT:   Entry: [[ENTRY:0x[0-9A-F]+]]
 # CHECK-NEXT:   ProgramHeaderOffset: 0x40
-# CHECK-NEXT:   SectionHeaderOffset: 0x1070
+# CHECK-NEXT:   SectionHeaderOffset: 0x1080
 # CHECK-NEXT:   Flags [ (0x0)
 # CHECK-NEXT:   ]
 # CHECK-NEXT:   HeaderSize: 64
 # CHECK-NEXT:   ProgramHeaderEntrySize: 56
 # CHECK-NEXT:   ProgramHeaderCount: 4
 # CHECK-NEXT:   SectionHeaderEntrySize: 64
-# CHECK-NEXT:   SectionHeaderCount: 5
-# CHECK-NEXT:   StringTableSectionIndex: 3
+# CHECK-NEXT:   SectionHeaderCount: 6
+# CHECK-NEXT:   StringTableSectionIndex: 4
 # CHECK-NEXT: }
 # CHECK-NEXT: Sections [
 # CHECK-NEXT:   Section {
 # CHECK-NEXT:     Index: 0
 # CHECK-NEXT:     Name:  (0)
 # CHECK-NEXT:     Type: SHT_NULL (0x0)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]

 # CHECK-NEXT:     Size: 16
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
 # CHECK-NEXT:     AddressAlignment: 4
 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
 # CHECK-NEXT:     Index: 2
+# CHECK-NEXT:     Name: .comment
+# CHECK-NEXT:     Type: SHT_PROGBITS (0x1)
+# CHECK-NEXT:     Flags [ (0x30)
+# CHECK-NEXT:       SHF_MERGE (0x10)
+# CHECK-NEXT:       SHF_STRINGS (0x20)
+# CHECK-NEXT:     ]
+# CHECK-NEXT:     Address: 0x0
+# CHECK-NEXT:     Offset: 0x1010
+# CHECK-NEXT:     Size: 8
+# CHECK-NEXT:     Link: 0
+# CHECK-NEXT:     Info: 0
+# CHECK-NEXT:     AddressAlignment: 1
+# CHECK-NEXT:     EntrySize: 1
+# CHECK-NEXT:   }
+# CHECK-NEXT:   Section {
+# CHECK-NEXT:     Index: 3
 # CHECK-NEXT:     Name: .symtab
 # CHECK-NEXT:     Type: SHT_SYMTAB (0x2)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x1010
+# CHECK-NEXT:     Offset: 0x1018
 # CHECK-NEXT:     Size: 48
-# CHECK-NEXT:     Link: 4
+# CHECK-NEXT:     Link: 5
 # CHECK-NEXT:     Info: 1
 # CHECK-NEXT:     AddressAlignment: 8
 # CHECK-NEXT:     EntrySize: 24
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
-# CHECK-NEXT:     Index: 3
+# CHECK-NEXT:     Index: 4
 # CHECK-NEXT:     Name: .shstrtab
 # CHECK-NEXT:     Type: SHT_STRTAB (0x3)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x1040
-# CHECK-NEXT:     Size: 33
+# CHECK-NEXT:     Offset: 0x1048
+# CHECK-NEXT:     Size: 42
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
 # CHECK-NEXT:     AddressAlignment: 1
 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
-# CHECK-NEXT:     Index: 4
+# CHECK-NEXT:     Index: 5
 # CHECK-NEXT:     Name: .strtab
 # CHECK-NEXT:     Type: SHT_STRTAB (0x3)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x1061
+# CHECK-NEXT:     Offset: 0x1072
 # CHECK-NEXT:     Size: 8
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
 # CHECK-NEXT:     AddressAlignment: 1
 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:   }
 # CHECK-NEXT: ]
 # CHECK-NEXT: Symbols [

test/ELF/basic32.s

 # CHECK-NEXT:     ABIVersion: 0
 # CHECK-NEXT:     Unused: (00 00 00 00 00 00 00)
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Type: Executable (0x2)
 # CHECK-NEXT:   Machine: EM_386 (0x3)
 # CHECK-NEXT:   Version: 1
 # CHECK-NEXT:   Entry: 0x11000
 # CHECK-NEXT:   ProgramHeaderOffset: 0x34
-# CHECK-NEXT:   SectionHeaderOffset: 0x1058
+# CHECK-NEXT:   SectionHeaderOffset: 0x1068
 # CHECK-NEXT:   Flags [ (0x0)
 # CHECK-NEXT:   ]
 # CHECK-NEXT:   HeaderSize: 52
 # CHECK-NEXT:   ProgramHeaderEntrySize: 32
 # CHECK-NEXT:   ProgramHeaderCount: 4
 # CHECK-NEXT:   SectionHeaderEntrySize: 40
-# CHECK-NEXT:   SectionHeaderCount: 5
-# CHECK-NEXT:   StringTableSectionIndex: 3
+# CHECK-NEXT:   SectionHeaderCount: 6
+# CHECK-NEXT:   StringTableSectionIndex: 4
 # CHECK-NEXT: }
 # CHECK-NEXT: Sections [
 # CHECK-NEXT:   Section {
 # CHECK-NEXT:     Index: 0
 # CHECK-NEXT:     Name:  (0)
 # CHECK-NEXT:     Type: SHT_NULL (0x0)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]

 # CHECK-NEXT:     Size: 12
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
 # CHECK-NEXT:     AddressAlignment: 4
 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
 # CHECK-NEXT:     Index: 2
+# CHECK-NEXT:     Name: .comment
+# CHECK-NEXT:     Type: SHT_PROGBITS (0x1)
+# CHECK-NEXT:     Flags [ (0x30)
+# CHECK-NEXT:       SHF_MERGE (0x10)
+# CHECK-NEXT:       SHF_STRINGS (0x20)
+# CHECK-NEXT:     ]
+# CHECK-NEXT:     Address: 0x0
+# CHECK-NEXT:     Offset: 0x100C
+# CHECK-NEXT:     Size: 8
+# CHECK-NEXT:     Link: 0
+# CHECK-NEXT:     Info: 0
+# CHECK-NEXT:     AddressAlignment: 1
+# CHECK-NEXT:     EntrySize: 1
+# CHECK-NEXT:   }
+# CHECK-NEXT:   Section {
+# CHECK-NEXT:     Index: 3
 # CHECK-NEXT:     Name: .symtab
 # CHECK-NEXT:     Type: SHT_SYMTAB
 # CHECK-NEXT:     Flags [
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x100C
+# CHECK-NEXT:     Offset: 0x1014
 # CHECK-NEXT:     Size: 32
-# CHECK-NEXT:     Link: 4
+# CHECK-NEXT:     Link: 5
 # CHECK-NEXT:     Info: 1
 # CHECK-NEXT:     AddressAlignment: 4
 # CHECK-NEXT:     EntrySize: 16
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
-# CHECK-NEXT:     Index: 3
+# CHECK-NEXT:     Index: 4
 # CHECK-NEXT:     Name: .shstrtab
 # CHECK-NEXT:     Type: SHT_STRTAB (0x3)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x102C
-# CHECK-NEXT:     Size: 33
+# CHECK-NEXT:     Offset: 0x1034
+# CHECK-NEXT:     Size: 42
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
 # CHECK-NEXT:     AddressAlignment: 1
 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
-# CHECK-NEXT:     Index: 4
+# CHECK-NEXT:     Index: 5
 # CHECK-NEXT:     Name: .strtab
 # CHECK-NEXT:     Type: SHT_STRTAB (0x3)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x104D
+# CHECK-NEXT:     Offset: 0x105E
 # CHECK-NEXT:     Size: 8
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
 # CHECK-NEXT:     AddressAlignment: 1
 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:   }
 # CHECK-NEXT: ]
 # CHECK-NEXT: ProgramHeaders [

test/ELF/basic64be.s

 # CHECK-NEXT:     ABIVersion: 0
 # CHECK-NEXT:     Unused: (00 00 00 00 00 00 00)
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Type: Executable (0x2)
 # CHECK-NEXT:   Machine: EM_PPC64 (0x15)
 # CHECK-NEXT:   Version: 1
 # CHECK-NEXT:   Entry: 0x10020040
 # CHECK-NEXT:   ProgramHeaderOffset: 0x40
-# CHECK-NEXT:   SectionHeaderOffset: 0x200C8
+# CHECK-NEXT:   SectionHeaderOffset: 0x200D8
 # CHECK-NEXT:   Flags [ (0x0)
 # CHECK-NEXT:   ]
 # CHECK-NEXT:   HeaderSize: 64
 # CHECK-NEXT:   ProgramHeaderEntrySize: 56
 # CHECK-NEXT:   ProgramHeaderCount: 6
 # CHECK-NEXT:   SectionHeaderEntrySize: 64
-# CHECK-NEXT:   SectionHeaderCount: 9
-# CHECK-NEXT:   StringTableSectionIndex: 7
+# CHECK-NEXT:   SectionHeaderCount: 10
+# CHECK-NEXT:   StringTableSectionIndex: 8
 # CHECK-NEXT: }
 # CHECK-NEXT: Sections [
 # CHECK-NEXT:   Section {
 # CHECK-NEXT:     Index: 0
 # CHECK-NEXT:     Name:  (0)
 # CHECK-NEXT:     Type: SHT_NULL (0x0)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]

 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:     SectionData (
 # CHECK-NEXT:       0000: 00000000 10010000 00000000 10028000 |................|
 # CHECK-NEXT:       0010: 00000000 00000000                   |........|
 # CHECK-NEXT:     )
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
 # CHECK-NEXT:     Index: 6
+# CHECK-NEXT:     Name: .comment
+# CHECK-NEXT:     Type: SHT_PROGBITS (0x1)
+# CHECK-NEXT:     Flags [ (0x30)
+# CHECK-NEXT:       SHF_MERGE (0x10)
+# CHECK-NEXT:       SHF_STRINGS (0x20)
+# CHECK-NEXT:     ]
+# CHECK-NEXT:     Address: 0x0
+# CHECK-NEXT:     Offset: 0x20058
+# CHECK-NEXT:     Size: 8
+# CHECK-NEXT:     Link: 0
+# CHECK-NEXT:     Info: 0
+# CHECK-NEXT:     AddressAlignment: 1
+# CHECK-NEXT:     EntrySize: 1
+# CHECK-NEXT:     SectionData (
+# CHECK-NEXT:         0000: 4C4C4420 312E3000 |LLD 1.0.|
+# CHECK-NEXT:     )
+# CHECK-NEXT:   }
+# CHECK-NEXT:   Section {
+# CHECK-NEXT:     Index: 7
 # CHECK-NEXT:     Name: .symtab
 # CHECK-NEXT:     Type: SHT_SYMTAB (0x2)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x20058
+# CHECK-NEXT:     Offset: 0x20060
 # CHECK-NEXT:     Size: 48
-# CHECK-NEXT:     Link: 8
+# CHECK-NEXT:     Link: 9
 # CHECK-NEXT:     Info: 1
 # CHECK-NEXT:     AddressAlignment: 8
 # CHECK-NEXT:     EntrySize: 24
 # CHECK-NEXT:     SectionData (
 # CHECK:          )
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
-# CHECK-NEXT:     Index: 7
+# CHECK-NEXT:     Index: 8
 # CHECK-NEXT:     Name: .shstrtab
 # CHECK-NEXT:     Type: SHT_STRTAB
 # CHECK-NEXT:     Flags [
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x20088
-# CHECK-NEXT:     Size: 54
+# CHECK-NEXT:     Offset: 0x20090
+# CHECK-NEXT:     Size: 63
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
 # CHECK-NEXT:     AddressAlignment: 1
 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:     SectionData (
 # CHECK:          )
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
-# CHECK-NEXT:     Index: 8
+# CHECK-NEXT:     Index: 9
 # CHECK-NEXT:     Name: .strtab
 # CHECK-NEXT:     Type: SHT_STRTAB
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x200BE
+# CHECK-NEXT:     Offset: 0x200CF
 # CHECK-NEXT:     Size: 8
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
 # CHECK-NEXT:     AddressAlignment: 1
 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:     SectionData (
 # CHECK-NEXT:       0000: 005F7374 61727400                    |._start.|
 # CHECK-NEXT:     )

test/ELF/build-id.s

_start:
   nop
 
 .section .note.test, "a", @note
    .quad 42
 
 # DEFAULT:      Contents of section .note.test:
 # DEFAULT:      Contents of section .note.gnu.build-id:
 # DEFAULT-NEXT: 04000000 08000000 03000000 474e5500  ............GNU.
-# DEFAULT-NEXT: ab
+# DEFAULT-NEXT: 6a
 
 # MD5:      Contents of section .note.gnu.build-id:
 # MD5-NEXT: 04000000 10000000 03000000 474e5500  ............GNU.
-# MD5-NEXT: 29
+# MD5-NEXT: 37
 
 # SHA1:      Contents of section .note.gnu.build-id:
 # SHA1-NEXT: 04000000 14000000 03000000 474e5500  ............GNU.
-# SHA1-NEXT: b1
-
-# TREE:      Contents of section .note.gnu.build-id:
-# TREE-NEXT: 04000000 14000000 03000000 474e5500  ............GNU.
-# TREE-NEXT: 18
+# SHA1-NEXT: 79
 
 # UUID:      Contents of section .note.gnu.build-id:
 # UUID-NEXT: 04000000 10000000 03000000 474e5500  ............GNU.
 
 # HEX:      Contents of section .note.gnu.build-id:
 # HEX-NEXT: 04000000 04000000 03000000 474e5500  ............GNU.
 # HEX-NEXT: 12345678
 
 # NONE-NOT: Contents of section .note.gnu.build-id:

test/ELF/comment-gc.s

 # REQUIRES: x86
 # RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t.o
 # RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %p/Inputs/comment-gc.s -o %t2.o
 # RUN: ld.lld %t.o %t2.o -o %t1 --gc-sections -shared
 # RUN: llvm-objdump -s %t1 | FileCheck %s
 
 # CHECK:      Contents of section .comment:
-# CHECK-NEXT:  0000 00666f6f 00626172 00 .foo.bar.
+# CHECK-NEXT:  0000 00666f6f 00626172 004c4c44 20312e30 .foo.bar.LLD 1.0
+# CHECK-NEXT:  0010 00 .
 
 .ident "foo"
 
 .globl _start
 _start:
   nop

test/ELF/gnu-ifunc-i386.s

 // CHECK-NEXT:  Name: .rel.plt
 // CHECK-NEXT:  Type: SHT_REL
 // CHECK-NEXT:  Flags [
 // CHECK-NEXT:    SHF_ALLOC
 // CHECK-NEXT:  ]
 // CHECK-NEXT:  Address: [[RELA:.*]]
 // CHECK-NEXT:  Offset: 0xD4
 // CHECK-NEXT:  Size: 16
-// CHECK-NEXT:  Link: 5
+// CHECK-NEXT:  Link: 6
 // CHECK-NEXT:  Info: 0
 // CHECK-NEXT:  AddressAlignment: 4
 // CHECK-NEXT:  EntrySize: 8
 // CHECK-NEXT: }
 // CHECK:     Relocations [
 // CHECK-NEXT:   Section ({{.*}}) .rel.plt {
 // CHECK-NEXT:     0x1200C R_386_IRELATIVE
 // CHECK-NEXT:     0x12010 R_386_IRELATIVE

test/ELF/gnu-ifunc.s

 // CHECK-NEXT:  Name: .rela.plt
 // CHECK-NEXT:  Type: SHT_RELA
 // CHECK-NEXT:  Flags [
 // CHECK-NEXT:    SHF_ALLOC
 // CHECK-NEXT:  ]
 // CHECK-NEXT:  Address: [[RELA:.*]]
 // CHECK-NEXT:  Offset: 0x158
 // CHECK-NEXT:  Size: 48
-// CHECK-NEXT:  Link: 5
+// CHECK-NEXT:  Link: 6
 // CHECK-NEXT:  Info: 0
 // CHECK-NEXT:  AddressAlignment: 8
 // CHECK-NEXT:  EntrySize: 24
 // CHECK-NEXT: }
 // CHECK:      Relocations [
 // CHECK-NEXT:   Section ({{.*}}) .rela.plt {
 // CHECK-NEXT:     0x12018 R_X86_64_IRELATIVE
 // CHECK-NEXT:     0x12020 R_X86_64_IRELATIVE

test/ELF/linkerscript/sections-keep.s

 # RUN: ld.lld --gc-sections -o %t1 --script %t.script %t
 # RUN: llvm-objdump -section-headers %t1 | FileCheck -check-prefix=MIXED1 %s
 # MIXED1:      Sections:
 # MIXED1-NEXT: Idx Name          Size
 # MIXED1-NEXT:   0               00000000
 # MIXED1-NEXT:   1 .keep         00000004
 # MIXED1-NEXT:   2 .text         00000007 00000000000000ec TEXT DATA
 # MIXED1-NEXT:   3 .temp         00000004 00000000000000f3 DATA
-# MIXED1-NEXT:   4 .symtab       00000060 0000000000000000
-# MIXED1-NEXT:   5 .shstrtab     0000002d 0000000000000000
-# MIXED1-NEXT:   6 .strtab       00000012 0000000000000000
+# MIXED1-NEXT:   4 .comment      00000008 0000000000000000
+# MIXED1-NEXT:   5 .symtab       00000060 0000000000000000
+# MIXED1-NEXT:   6 .shstrtab     00000036 0000000000000000
+# MIXED1-NEXT:   7 .strtab       00000012 0000000000000000
 
 ## The same, but now section without KEEP is at first place.
 ## gold and bfd linkers disagree here. gold collects .keep while
 ## bfd keeps it. Our current behavior is compatible with bfd although
 ## we can choose either way.
 # RUN: echo "SECTIONS { \
 # RUN:  . = SIZEOF_HEADERS; \
 # RUN:  .nokeep : { *(.keep) } \
 # RUN:  .keep : { KEEP(*(.keep)) }}" > %t.script
 # RUN: ld.lld --gc-sections -o %t1 --script %t.script %t
 # RUN: llvm-objdump -section-headers %t1 | FileCheck -check-prefix=MIXED2 %s
 # MIXED2:      Sections:
 # MIXED2-NEXT: Idx Name          Size
 # MIXED2-NEXT:   0               00000000
 # MIXED2-NEXT:   1 .nokeep       00000004 00000000000000e8 DATA
 # MIXED2-NEXT:   2 .text         00000007 00000000000000ec TEXT DATA
 # MIXED2-NEXT:   3 .temp         00000004 00000000000000f3 DATA
-# MIXED2-NEXT:   4 .symtab       00000060 0000000000000000
-# MIXED2-NEXT:   5 .shstrtab     0000002f 0000000000000000
-# MIXED2-NEXT:   6 .strtab       00000012 0000000000000000
+# MIXED2-NEXT:   4 .comment      00000008 0000000000000000
+# MIXED2-NEXT:   5 .symtab       00000060 0000000000000000
+# MIXED2-NEXT:   6 .shstrtab     00000038 0000000000000000
+# MIXED2-NEXT:   7 .strtab       00000012 0000000000000000
 
 # Check file pattern for kept sections.
 # RUN: echo "SECTIONS { \
 # RUN:  . = SIZEOF_HEADERS; \
 # RUN:  .keep : { KEEP(*2.o(.keep)) } \
 # RUN:  }" > %t.script
 # RUN: ld.lld --gc-sections -o %t1 --script %t.script %t2.o %t
 # RUN: llvm-objdump -s %t1 | FileCheck -check-prefix=FILEMATCH %s

test/ELF/linkerscript/sections-sort.s

 # CHECK: Id
 # CHECK-NEXT: 0
 # CHECK-NEXT: 1 .text
 # CHECK-NEXT: 2 foo
 # CHECK-NEXT: 3 .dynsym
 # CHECK-NEXT: 4 .hash
 # CHECK-NEXT: 5 .dynstr
 # CHECK-NEXT: 6 .dynamic
-# CHECK-NEXT: 7 .symtab
-# CHECK-NEXT: 8 .shstrtab
-# CHECK-NEXT: 9 .strtab
+# CHECK-NEXT: 7 .comment
+# CHECK-NEXT: 8 .symtab
+# CHECK-NEXT: 9 .shstrtab
+# CHECK-NEXT: 10 .strtab

test/ELF/linkerscript/sections.s

 # RUN:   FileCheck -check-prefix=SEC-DEFAULT %s
 
 #             Idx Name          Size
 # SEC-DEFAULT: 1 .text         0000000e {{[0-9a-f]*}} TEXT DATA
 # SEC-DEFAULT: 2 .data         00000020 {{[0-9a-f]*}} DATA
 # SEC-DEFAULT: 3 other         00000003 {{[0-9a-f]*}} DATA
 # SEC-DEFAULT: 4 .bss          00000002 {{[0-9a-f]*}} BSS
 # SEC-DEFAULT: 5 .shstrtab     00000002 {{[0-9a-f]*}}
-# SEC-DEFAULT: 6 .symtab       00000030 {{[0-9a-f]*}}
-# SEC-DEFAULT: 7 .shstrtab     00000032 {{[0-9a-f]*}}
-# SEC-DEFAULT: 8 .strtab       00000008 {{[0-9a-f]*}}
+# SEC-DEFAULT: 6 .comment      00000008 {{[0-9a-f]*}}
+# SEC-DEFAULT: 7 .symtab       00000030 {{[0-9a-f]*}}
+# SEC-DEFAULT: 8 .shstrtab     0000003b {{[0-9a-f]*}}
+# SEC-DEFAULT: 9 .strtab       00000008 {{[0-9a-f]*}}
 
 # Sections are put in order specified in linker script, other than alloc
 # sections going first.
 # RUN: echo "SECTIONS { \
 # RUN:          .bss : { *(.bss) } \
 # RUN:          other : { *(other) } \
 # RUN:          .shstrtab : { *(.shstrtab) } \
 # RUN:          .symtab : { *(.symtab) } \
 # RUN:          .strtab : { *(.strtab) } \
 # RUN:          .data : { *(.data) } \
 # RUN:          .text : { *(.text) } }" > %t.script
 # RUN: ld.lld -o %t3 --script %t.script %t
 # RUN: llvm-objdump -section-headers %t3 | \
 # RUN:   FileCheck -check-prefix=SEC-ORDER %s
 
 #           Idx Name          Size
 # SEC-ORDER: 1 .bss          00000002 {{[0-9a-f]*}} BSS
 # SEC-ORDER: 2 other         00000003 {{[0-9a-f]*}} DATA
 # SEC-ORDER: 3 .shstrtab     00000002 {{[0-9a-f]*}}
-# SEC-ORDER: 4 .shstrtab     00000032 {{[0-9a-f]*}}
+# SEC-ORDER: 4 .shstrtab     0000003b {{[0-9a-f]*}}
 # SEC-ORDER: 5 .symtab       00000030 {{[0-9a-f]*}}
 # SEC-ORDER: 6 .strtab       00000008 {{[0-9a-f]*}}
 # SEC-ORDER: 7 .data         00000020 {{[0-9a-f]*}} DATA
 # SEC-ORDER: 8 .text         0000000e {{[0-9a-f]*}} TEXT DATA
 
 # .text and .data have swapped names but proper sizes and types.
 # RUN: echo "SECTIONS { \
 # RUN:          .data : { *(.text) } \
 # RUN:          .text : { *(.data) } }" > %t.script
 # RUN: ld.lld -o %t4 --script %t.script %t
 # RUN: llvm-objdump -section-headers %t4 | \
 # RUN:   FileCheck -check-prefix=SEC-SWAP-NAMES %s
 
 #                Idx Name          Size
 # SEC-SWAP-NAMES: 1 .data         0000000e {{[0-9a-f]*}} TEXT DATA
 # SEC-SWAP-NAMES: 2 .text         00000020 {{[0-9a-f]*}} DATA
 # SEC-SWAP-NAMES: 3 other         00000003 {{[0-9a-f]*}} DATA
 # SEC-SWAP-NAMES: 4 .bss          00000002 {{[0-9a-f]*}} BSS
 # SEC-SWAP-NAMES: 5 .shstrtab     00000002 {{[0-9a-f]*}}
-# SEC-SWAP-NAMES: 6 .symtab       00000030 {{[0-9a-f]*}}
-# SEC-SWAP-NAMES: 7 .shstrtab     00000032 {{[0-9a-f]*}}
-# SEC-SWAP-NAMES: 8 .strtab       00000008 {{[0-9a-f]*}}
+# SEC-SWAP-NAMES: 6 .comment      00000008 {{[0-9a-f]*}}
+# SEC-SWAP-NAMES: 7 .symtab       00000030 {{[0-9a-f]*}}
+# SEC-SWAP-NAMES: 8 .shstrtab     0000003b {{[0-9a-f]*}}
+# SEC-SWAP-NAMES: 9 .strtab       00000008 {{[0-9a-f]*}}
 
 # .shstrtab from the input object file is discarded.
 # RUN: echo "SECTIONS { \
 # RUN:          /DISCARD/ : { *(.shstrtab) } }" > %t.script
 # RUN: ld.lld -o %t5 --script %t.script %t
 # RUN: llvm-objdump -section-headers %t5 | \
 # RUN:   FileCheck -check-prefix=SEC-DISCARD %s
 
 #             Idx Name          Size
 # SEC-DISCARD: 1 .text         0000000e {{[0-9a-f]*}} TEXT DATA
 # SEC-DISCARD: 2 .data         00000020 {{[0-9a-f]*}} DATA
 # SEC-DISCARD: 3 other         00000003 {{[0-9a-f]*}} DATA
 # SEC-DISCARD: 4 .bss          00000002 {{[0-9a-f]*}} BSS
-# SEC-DISCARD: 5 .symtab       00000030 {{[0-9a-f]*}}
-# SEC-DISCARD: 6 .shstrtab     00000032 {{[0-9a-f]*}}
-# SEC-DISCARD: 7 .strtab       00000008 {{[0-9a-f]*}}
+# SEC-DISCARD: 5 .comment      00000008 {{[0-9a-f]*}}
+# SEC-DISCARD: 6 .symtab       00000030 {{[0-9a-f]*}}
+# SEC-DISCARD: 7 .shstrtab     0000003b {{[0-9a-f]*}}
+# SEC-DISCARD: 8 .strtab       00000008 {{[0-9a-f]*}}
 
 # Multiple SECTIONS command specifying additional input section descriptions
 # for the same output section description - input sections are merged into
 # one output section.
 # RUN: echo "SECTIONS { \
 # RUN:          .text : { *(.text) } \
 # RUN:          .data : { *(.data) } } \
 # RUN:       SECTIONS { \
 # RUN:          .data : { *(other) } }" > %t.script
 # RUN: ld.lld -o %t6 --script %t.script %t
 # RUN: llvm-objdump -section-headers %t6 | \
 # RUN:   FileCheck -check-prefix=SEC-MULTI %s
 
 #           Idx Name          Size
 # SEC-MULTI: 1 .text         0000000e {{[0-9a-f]*}} TEXT DATA
 # SEC-MULTI: 2 .data         00000023 {{[0-9a-f]*}} DATA
 # SEC-MULTI: 3 .bss          00000002 {{[0-9a-f]*}} BSS
 # SEC-MULTI: 4 .shstrtab     00000002 {{[0-9a-f]*}}
-# SEC-MULTI: 5 .symtab       00000030 {{[0-9a-f]*}}
-# SEC-MULTI: 6 .shstrtab     0000002c {{[0-9a-f]*}}
-# SEC-MULTI: 7 .strtab       00000008 {{[0-9a-f]*}}
+# SEC-MULTI: 5 .comment      00000008 {{[0-9a-f]*}}
+# SEC-MULTI: 6 .symtab       00000030 {{[0-9a-f]*}}
+# SEC-MULTI: 7 .shstrtab     00000035 {{[0-9a-f]*}}
+# SEC-MULTI: 8 .strtab       00000008 {{[0-9a-f]*}}
 
 .globl _start
 _start:
     mov $60, %rax
     mov $42, %rdi
 
 .section .data,"aw"
 .quad 10, 10, 20, 20
 .section other,"aw"
 .short 10
 .byte 20
 .section .shstrtab,""
 .short 20
 .section .bss,"",@nobits
 .short 0

test/ELF/linkerscript/wildcards.s

 # REQUIRES: x86
 # RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
 
 ## Default case: abc and abx included in text.
 # RUN: echo "SECTIONS { \
 # RUN:      .text : { *(.abc .abx) } }" > %t.script
 # RUN: ld.lld -o %t.out --script %t.script %t
 # RUN: llvm-objdump -section-headers %t.out | \
 # RUN:   FileCheck -check-prefix=SEC-DEFAULT %s
 # SEC-DEFAULT:      Sections:
 # SEC-DEFAULT-NEXT: Idx Name          Size
 # SEC-DEFAULT-NEXT:   0               00000000
 # SEC-DEFAULT-NEXT:   1 .text         00000008
 # SEC-DEFAULT-NEXT:   2 .abcd         00000004
 # SEC-DEFAULT-NEXT:   3 .ad           00000004
 # SEC-DEFAULT-NEXT:   4 .ag           00000004
-# SEC-DEFAULT-NEXT:   5 .symtab       00000030
-# SEC-DEFAULT-NEXT:   6 .shstrtab     0000002f
-# SEC-DEFAULT-NEXT:   7 .strtab       00000008
+# SEC-DEFAULT-NEXT:   5 .comment      00000008 {{[0-9a-f]*}}
+# SEC-DEFAULT-NEXT:   6 .symtab       00000030
+# SEC-DEFAULT-NEXT:   7 .shstrtab     00000038
+# SEC-DEFAULT-NEXT:   8 .strtab       00000008
 
 ## Now replace the symbol with '?' and check that results are the same.
 # RUN: echo "SECTIONS { \
 # RUN:      .text : { *(.abc .ab?) } }" > %t.script
 # RUN: ld.lld -o %t.out --script %t.script %t
 # RUN: llvm-objdump -section-headers %t.out | \
 # RUN:   FileCheck -check-prefix=SEC-DEFAULT %s
 
 ## Now see how replacing '?' with '*' will consume whole abcd.
 # RUN: echo "SECTIONS { \
 # RUN:      .text : { *(.abc .ab*) } }" > %t.script
 # RUN: ld.lld -o %t.out --script %t.script %t
 # RUN: llvm-objdump -section-headers %t.out | \
 # RUN:   FileCheck -check-prefix=SEC-ALL %s
 # SEC-ALL:      Sections:
 # SEC-ALL-NEXT: Idx Name          Size
 # SEC-ALL-NEXT:   0               00000000
 # SEC-ALL-NEXT:   1 .text         0000000c
 # SEC-ALL-NEXT:   2 .ad           00000004
 # SEC-ALL-NEXT:   3 .ag           00000004
-# SEC-ALL-NEXT:   4 .symtab       00000030
-# SEC-ALL-NEXT:   5 .shstrtab     00000029
-# SEC-ALL-NEXT:   6 .strtab       00000008
+# SEC-ALL-NEXT:   4 .comment      00000008
+# SEC-ALL-NEXT:   5 .symtab       00000030
+# SEC-ALL-NEXT:   6 .shstrtab     00000032
+# SEC-ALL-NEXT:   7 .strtab       00000008
 
 ## All sections started with .a are merged.
 # RUN: echo "SECTIONS { \
 # RUN:      .text : { *(.a*) } }" > %t.script
 # RUN: ld.lld -o %t.out --script %t.script %t
 # RUN: llvm-objdump -section-headers %t.out | \
 # RUN:   FileCheck -check-prefix=SEC-NO %s
 # SEC-NO: Sections:
 # SEC-NO-NEXT: Idx Name          Size
 # SEC-NO-NEXT:   0               00000000
 # SEC-NO-NEXT:   1 .text         00000014
-# SEC-NO-NEXT:   2 .symtab       00000030
-# SEC-NO-NEXT:   3 .shstrtab     00000021
-# SEC-NO-NEXT:   4 .strtab       00000008
+# SEC-NO-NEXT:   2 .comment      00000008
+# SEC-NO-NEXT:   3 .symtab       00000030
+# SEC-NO-NEXT:   4 .shstrtab     0000002a
+# SEC-NO-NEXT:   5 .strtab       00000008
 
 .text
 .section .abc,"ax",@progbits
 .long 0
 
 .text
 .section .abx,"ax",@progbits
 .long 0

test/ELF/pie.s

 # CHECK-NEXT:    ABIVersion: 0
 # CHECK-NEXT:    Unused: (00 00 00 00 00 00 00)
 # CHECK-NEXT:  }
 # CHECK-NEXT:  Type: SharedObject
 # CHECK-NEXT:  Machine: EM_X86_64
 # CHECK-NEXT:  Version: 1
 # CHECK-NEXT:  Entry: 0x1000
 # CHECK-NEXT:  ProgramHeaderOffset: 0x40
-# CHECK-NEXT:  SectionHeaderOffset: 0x1110
+# CHECK-NEXT:  SectionHeaderOffset: 0x1120
 # CHECK-NEXT:  Flags [
 # CHECK-NEXT:  ]
 # CHECK-NEXT:  HeaderSize: 64
 # CHECK-NEXT:  ProgramHeaderEntrySize: 56
 # CHECK-NEXT:  ProgramHeaderCount: 7
 # CHECK-NEXT:  SectionHeaderEntrySize: 64
-# CHECK-NEXT:  SectionHeaderCount: 9
-# CHECK-NEXT:  StringTableSectionIndex: 7
+# CHECK-NEXT:  SectionHeaderCount: 10
+# CHECK-NEXT:  StringTableSectionIndex: 8
 # CHECK-NEXT: }
 
 # CHECK:      ProgramHeaders [
 # CHECK-NEXT:  ProgramHeader {
 # CHECK-NEXT:    Type: PT_PHDR
 # CHECK-NEXT:    Offset: 0x40
 # CHECK-NEXT:    VirtualAddress: 0x40
 # CHECK-NEXT:    PhysicalAddress: 0x40

test/ELF/relocatable-bss.s

 # CHECK-NEXT:    ABIVersion: 0
 # CHECK-NEXT:    Unused: (00 00 00 00 00 00 00)
 # CHECK-NEXT:  }
 # CHECK-NEXT:  Type: Relocatable
 # CHECK-NEXT:  Machine: EM_X86_64
 # CHECK-NEXT:  Version:
 # CHECK-NEXT:  Entry:
 # CHECK-NEXT:   ProgramHeaderOffset:
-# CHECK-NEXT:   SectionHeaderOffset: 0xA8
+# CHECK-NEXT:   SectionHeaderOffset: 0xB8
 # CHECK-NEXT:  Flags [
 # CHECK-NEXT:  ]
 # CHECK-NEXT:  HeaderSize:
 # CHECK-NEXT:  ProgramHeaderEntrySize:
 # CHECK-NEXT:  ProgramHeaderCount:
 # CHECK-NEXT:  SectionHeaderEntrySize:
 # CHECK-NEXT:  SectionHeaderCount:
 # CHECK-NEXT:  StringTableSectionIndex:

test/ELF/relocatable.s

 # CHECK-NEXT:    ABIVersion: 0
 # CHECK-NEXT:    Unused: (00 00 00 00 00 00 00)
 # CHECK-NEXT:  }
 # CHECK-NEXT:  Type: Relocatable
 # CHECK-NEXT:  Machine: EM_X86_64
 # CHECK-NEXT:  Version: 1
 # CHECK-NEXT:  Entry: 0x0
 # CHECK-NEXT:  ProgramHeaderOffset: 0x0
-# CHECK-NEXT:  SectionHeaderOffset: 0x2C0
+# CHECK-NEXT:  SectionHeaderOffset: 0x2D0
 # CHECK-NEXT:  Flags [
 # CHECK-NEXT:  ]
 # CHECK-NEXT:  HeaderSize: 64
 # CHECK-NEXT:  ProgramHeaderEntrySize: 0
 # CHECK-NEXT:  ProgramHeaderCount: 0
 # CHECK-NEXT:  SectionHeaderEntrySize: 64
-# CHECK-NEXT:  SectionHeaderCount: 7
-# CHECK-NEXT:  StringTableSectionIndex: 5
+# CHECK-NEXT:  SectionHeaderCount: 8
+# CHECK-NEXT:  StringTableSectionIndex: 6
 # CHECK-NEXT:  }
 
 # CHECK:       Relocations [
 # CHECK-NEXT:  Section (3) .rela.text {
 # CHECK-NEXT:    0x3 R_X86_64_32S x 0x0
 # CHECK-NEXT:    0xE R_X86_64_32S y 0x0
 # CHECK-NEXT:    0x23 R_X86_64_32S xx 0x0
 # CHECK-NEXT:    0x2E R_X86_64_32S yy 0x0

 # CHECKEXE-NEXT:      ABIVersion: 0
 # CHECKEXE-NEXT:      Unused: (00 00 00 00 00 00 00)
 # CHECKEXE-NEXT:    }
 # CHECKEXE-NEXT:    Type: Executable
 # CHECKEXE-NEXT:    Machine: EM_X86_64
 # CHECKEXE-NEXT:    Version: 1
 # CHECKEXE-NEXT:    Entry: 0x11000
 # CHECKEXE-NEXT:    ProgramHeaderOffset: 0x40
-# CHECKEXE-NEXT:    SectionHeaderOffset: 0x11E8
+# CHECKEXE-NEXT:    SectionHeaderOffset: 0x11F8
 # CHECKEXE-NEXT:    Flags [
 # CHECKEXE-NEXT:    ]
 # CHECKEXE-NEXT:    HeaderSize: 64
 # CHECKEXE-NEXT:    ProgramHeaderEntrySize: 56
 # CHECKEXE-NEXT:    ProgramHeaderCount: 5
 # CHECKEXE-NEXT:    SectionHeaderEntrySize: 64
-# CHECKEXE-NEXT:    SectionHeaderCount: 6
-# CHECKEXE-NEXT:    StringTableSectionIndex: 4
+# CHECKEXE-NEXT:    SectionHeaderCount: 7
+# CHECKEXE-NEXT:    StringTableSectionIndex: 5
 # CHECKEXE-NEXT:  }
 
 .text
 .type x,@object
 .bss
 .globl x
 .align 4
 x:

test/ELF/section-name.s

 // CHECK:  4 .tdata        00000001
 // CHECK:  5 .tbss         00000001
 // CHECK:  6 .data.rel.ro  00000004
 // CHECK:  7 .data         00000002
 // CHECK:  8 .foo.a        00000001
 // CHECK:  9 .foo          00000001
 // CHECK: 10 .bss          00000001
 // CHECK: 11 .bss          00000001
-// CHECK: 12 .symtab       00000060
-// CHECK: 13 .shstrtab     0000006c
-// CHECK: 14 .strtab       0000001d
+// CHECK: 12 .comment      00000008
+// CHECK: 13 .symtab       00000060
+// CHECK: 14 .shstrtab     00000075
+// CHECK: 15 .strtab       0000001d

test/ELF/shared.s

 // RUN: llvm-mc -filetype=obj -triple=i686-unknown-linux %s -o %t.o
 // RUN: llvm-mc -filetype=obj -triple=i686-unknown-linux %p/Inputs/shared.s -o %t2.o
 // RUN: ld.lld -shared %t2.o -o %t2.so
 // RUN: llvm-readobj -s %t2.so | FileCheck --check-prefix=SO %s
 // RUN: ld.lld -dynamic-linker /lib64/ld-linux-x86-64.so.2 -rpath foo -rpath bar --export-dynamic %t.o %t2.so -o %t
 // RUN: llvm-readobj --program-headers --dynamic-table -t -s -dyn-symbols -section-data -hash-table %t | FileCheck %s
 // RUN: ld.lld %t.o %t2.so %t2.so -o %t2
 // RUN: llvm-readobj -dyn-symbols %t2 | FileCheck --check-prefix=DONT_EXPORT %s
 // REQUIRES: x86
 
 // Make sure .symtab is properly aligned.
 // SO:      Name: .symtab
 // SO-NEXT: Type: SHT_SYMTAB
 // SO-NEXT: Flags [
 // SO-NEXT: ]
 // SO-NEXT: Address:
-// SO-NEXT: Offset: 0x1030
+// SO-NEXT: Offset: 0x1038
 // SO-NEXT: Size:
 // SO-NEXT: Link:
 // SO-NEXT: Info:
 // SO-NEXT: AddressAlignment: 4
 
 // CHECK:        Name: .interp
 // CHECK-NEXT:   Type: SHT_PROGBITS
 // CHECK-NEXT:   Flags [

test/ELF/string-table.s

 // CHECK-NEXT:  Offset:
 // CHECK-NEXT:  Size:
 // CHECK-NEXT:  Link: 0
 // CHECK-NEXT:  Info: 0
 // CHECK-NEXT:  AddressAlignment: 1
 // CHECK-NEXT:  EntrySize: 0
 // CHECK-NEXT:  SectionData (
 // CHECK-NEXT:    0000: 00626172 002E7465 78740066 6F6F6261  |.bar..text.fooba|
-// CHECK-NEXT:    0010: 72002E73 796D7461 62002E73 68737472  |r..symtab..shstr|
-// CHECK-NEXT:    0020: 74616200 2E737472 74616200           |tab..strtab.|
+// CHECK-NEXT:    0010: 72002E63 6F6D6D65 6E74002E 73796D74  |r..comment..symt|
+// CHECK-NEXT:    0020: 6162002E 73687374 72746162 002E7374  |ab..shstrtab..st|
+// CHECK-NEXT:    0030: 72746162 00                          |rtab.|
 // CHECK-NEXT:  )
 // CHECK-NEXT:}
 // CHECK:        Name: .strtab
 // CHECK-NEXT:   Type: SHT_STRTAB (0x3)
 // CHECK-NEXT:   Flags [ (0x0)
 // CHECK-NEXT:   ]
 // CHECK-NEXT:   Address: 0x0
 // CHECK-NEXT:   Offset:

test/lit.cfg

 if re.search(r'X86', archs):
     config.available_features.add('x86')
 if re.search(r'PowerPC', archs):
     config.available_features.add('ppc')
 if re.search(r'AMDGPU', archs):
     config.available_features.add('amdgpu')
 llvm_config_cmd.wait()
 
+# Set a fake constant version so that we get consitent output.
+config.environment['LLD_VERSION'] = 'LLD 1.0'
+
 # Check if Windows resource file compiler exists.
 cvtres = lit.util.which('cvtres', config.environment['PATH'])
 rc = lit.util.which('rc', config.environment['PATH'])
 if cvtres and rc:
     config.available_features.add('winres')
 
 # Check if "lib.exe" command exists.
 if lit.util.which('lib', config.environment['PATH']):
     config.available_features.add('winlib')
 
 # Check if "cpio" command exists.
 if lit.util.which('cpio', config.environment['PATH']):
     config.available_features.add('cpio')