[yaml2obj][obj2yaml] - Do not create a symbol table by default.

[grimar]

Summary

This patch tries to resolve problems faced in D68943
and uses some of the code written by Konrad Wilhelm Kleine
in that patch.

Previously, yaml2obj tool always created a .symtab section.
This patch changes that. With it we only create it when
have a "Symbols:" tag in the YAML document or when
we need to create it because it is used by another section(s).

obj2yaml follows the new behavior and does not print "Symbols:"
anymore when there is no symbol table.

It touches and changes many test cases and also reveals 2 issues
(one of them is a crash) in llvm-objcopy tool. I added a TODO mark
with the descriptions to their test cases.

[MaskRay]

lib/ObjectYAML/ELFEmitter.cpp

208

if (Doc.Symbols) continue; can be factored out.

test/tools/yaml2obj/symtab-implicit-sections-flags.yaml

80

In other places, you seem to use Symbols: []

[kwk]

@grimar I don't understand why you created this patch, when I'm working on it already.

lib/ObjectYAML/ELFEmitter.cpp

208

I agree with this optimization.

But I also wonder why you say that some section link to .symtab by default. So far I've only seen explicit references to .symtab in the Link: .symtab entry of a section in a test file. So why not change the test files to point to an existing section (you changed most of them anyways)? Or will a an empty Link: entry automatically point to .symtab?

232

Change to ImplicitSections.insert(ImplicitSections.end(), {".strtab", ".shstrtab"});

test/Object/invalid.test

295

Isn't Symbols: enough?

test/tools/llvm-objcopy/ELF/segment-test-remove-section.test

45

I suggest to use TODO(username): .

test/tools/yaml2obj/implicit-sections-types.test

28

See, apparently it is enough ;)

test/tools/yaml2obj/implicit-sections.test

88

Great, that you've put this all into one file.

[rupprecht]

lib/ObjectYAML/ELFEmitter.cpp

209–210

I think SHT_HASH, SHT_GROUP, and SHT_SYMTAB_SHNDX might also belong here, per: http://www.sco.com/developers/gabi/latest/ch4.sheader.html#sh_link

At that point, it might look cleaner to refactor out the list as a separate variable that is checked for list/set containment

214–218

This case is interesting, partly because IIRC we raise an error if someone specifies a link to a section that does not exist, so special casing this seems unexpected. However, I imagine many tests would need to be fixed and it's maybe not worth it -- have you checked how many tests would fail if you didn't special case this?

231

Is .strtab also something we can drop if .symtab doesn't exist?

[grimar]

In D69041#1711707, @kwk wrote:

@grimar I don't understand why you created this patch, when I'm working on it already.

I only wanted to help, because supposed that the correct direction is not clear for you (since your version did not fix any of existent test cases that were failing,
obj2yaml tool did not compile and there was at least one obliously wrong place in 'initSymtabSectionHeader' that broke the normal logic).
And it was also not fully clear to me what is exactly needed until I run check-llvm with the first more or less stable version of the patch at least.

Now when the whole picture is revealed, feel free to commandeer this revision or use it as a reference for your patch if you would like to continue it.
Or let me continue. Please let me know about your decision, I'll put this on hold until that.

[kwk]

In D69041#1712432, @grimar wrote:

In D69041#1711707, @kwk wrote:

@grimar I don't understand why you created this patch, when I'm working on it already.

I only wanted to help, because supposed that the correct direction is not clear for you (since your version did not fix any of existent test cases that were failing,
obj2yaml tool did not compile and there was at least one obliously wrong place in 'initSymtabSectionHeader' that broke the normal logic).
And it was also not fully clear to me what is exactly needed until I run check-llvm with the first more or less stable version of the patch at least.

Now when the whole picture is revealed, feel free to commandeer this revision or use it as a reference for your patch if you would like to continue it.
Or let me continue. Please let me know about your decision, I'll put this on hold until that.

@grimar I'm really sorry that I wrote this yesterday. I'm working crazy hours lately and wasn't in a bad mood. I understand why you wrote the patch now. But since it wasn't something urgent to do and only motivated because I brought it up, I didn't fully understood how little time I was given to react to your comments in my own patch. I will discontinue it as you obviously have more experience in the yaml2obj and obj2yaml code. What's bugging me is just that I wanted to contribute and didn't have enough time to properly do so, that's all.

[grimar]

In D69041#1712474, @kwk wrote:

In D69041#1712432, @grimar wrote:

In D69041#1711707, @kwk wrote:

@grimar I don't understand why you created this patch, when I'm working on it already.

I only wanted to help, because supposed that the correct direction is not clear for you (since your version did not fix any of existent test cases that were failing,
obj2yaml tool did not compile and there was at least one obliously wrong place in 'initSymtabSectionHeader' that broke the normal logic).
And it was also not fully clear to me what is exactly needed until I run check-llvm with the first more or less stable version of the patch at least.

Now when the whole picture is revealed, feel free to commandeer this revision or use it as a reference for your patch if you would like to continue it.
Or let me continue. Please let me know about your decision, I'll put this on hold until that.

@grimar I'm really sorry that I wrote this yesterday. I'm working crazy hours lately and wasn't in a bad mood. I understand why you wrote the patch now. But since it wasn't something urgent to do and only motivated because I brought it up, I didn't fully understood how little time I was given to react to your comments in my own patch. I will discontinue it as you obviously have more experience in the yaml2obj and obj2yaml code. What's bugging me is just that I wanted to contribute and didn't have enough time to properly do so, that's all.

No problems. Hope we will land it soon :)

[MaskRay]

In D69041#1711707, @kwk wrote:

@grimar I don't understand why you created this patch, when I'm working on it already.

@kwk Sorry if you feel your work is commandeered. On D68943, it was me who said

Nice! Can you post a differential for the yaml2obj change? I believe the differential can focus on lldb and remove yaml2obj changes (kwk will still get credited for the test cleanups).

I skimmed through your yaml2obj changes in D68943 and I believed a complete fix needs more work than your change. check-llvm-tools check-llvm-object should expose more tests that you missed. George has done tons of work in yaml2obj/obj2yaml in the recent months and he probably knows the code better than anyone else. If you read this patch more carefully, you should notice that your version differs a lot from his version.

Apologies if you feel sad, but as I said you should still get credits for your lldb changes. Why do you abandon D68943? You can still keep the lldb part.

[kwk]

In D69041#1712493, @MaskRay wrote:

In D69041#1711707, @kwk wrote:

@grimar I don't understand why you created this patch, when I'm working on it already.

@kwk Sorry if you feel your work is commandeered. On D68943, it was me who said

Nice! Can you post a differential for the yaml2obj change? I believe the differential can focus on lldb and remove yaml2obj changes (kwk will still get credited for the test cleanups).

I skimmed through your yaml2obj changes in D68943 and I believed a complete fix needs more work than your change. check-llvm-tools check-llvm-object should expose more tests that you missed.

I know (D68943#1708113) that I did miss tests and simply haven't updated my diff. I was still fixing some tests locally (D68943#1709330). I didn't ask nor expected somebody to run tests.

George has done tons of work in yaml2obj/obj2yaml in the recent months and he probably knows the code better than anyone else. If you read this patch more carefully, you should notice that your version differs a lot from his version.

The basic idea is the same only that he cover's Link: entries as well and has fixed more tests (which I also had locally).

Apologies if you feel sad, but as I said you should still get credits for your lldb changes. Why do you abandon D68943? You can still keep the lldb part.

I will add the LLDB part (which was only about removing .symtab manually) once Geroge's test has landed. Let's keep my feelings out of this for a bit ;)

[MaskRay]

lib/ObjectYAML/ELFEmitter.cpp

209–210

sh_link(.hash) = .dynsym (not .symtab)

For SHT_GROUP and SHT_SYMTAB_SHNDX, we don't have implicit sh_link = .symtab rule.

It does raise the question: shall we keep the number of implicit .symtab rules low? Are we happy to keep the implicit rule for SHT_REL and SHT_RELA?

212

Doc.Symbols.emplace()

Same below.

test/tools/yaml2obj/implicit-sections.test

88

Typo: spicified

I think the YAML term is mapping key, or key, not tag. Tag refers to a different thing (https://yaml.org/spec/1.2/spec.html#id2764295).

91

This can be FileCheck /dev/null --implicit-check-not=.symtab if you feel it is clearer.

102

Typo: spicified -> specified

[grimar]

• Addressed review comments.

[grimar]

lib/ObjectYAML/ELFEmitter.cpp

208

But I also wonder why you say that some section link to .symtab by default. So far I've only seen explicit references to .symtab in the Link: .symtab entry of a section in a test file.
Or will a an empty Link: entry automatically point to .symtab?

For SHT_REL[A] we set it to .symtab when there is no Link at all (and .strtab is mandatory to have in this case atm):
https://github.com/llvm-mirror/llvm/blob/master/lib/ObjectYAML/ELFEmitter.cpp#L722

The same we do for SHT_LLVM_ADDRSIG (though in this case there will be no error when .strtab is missing).
https://github.com/llvm-mirror/llvm/blob/master/lib/ObjectYAML/ELFEmitter.cpp#L1007

209–210

At that point, it might look cleaner to refactor out the list as a separate variable that is checked for list/set containment

It does raise the question: shall we keep the number of implicit .symtab rules low? Are we happy to keep the implicit rule for SHT_REL and SHT_RELA?

Interesting question. So what about we do a change to yaml2obj to remove the additional logic added here?
I.e.:

1. <I've done this> Remove the logic for SHT_LLVM_ADDRSIG from here. SHT_LLVM_ADDRSIG just sets the Link to 0 when there is no .symtab already. So it was a quick change on a test suite side.
2. Keep the logic for SHT_REL and SHT_RELA here in this patch for now.
3. Remove it and change our logic in a follow up, i.e. change it to stop producing errors for relocation sections when there is no .symtab section. Rel[A] Sections will start to get 0 as a Link value. Just like we do for SHT_LLVM_ADDRSIG currently.

214–218

Good point. There were about 20 of tests, but I've fixed them instead. It reduces the number of rules, what makes sence too I think.

231

Yes, seems we can do this. I tried and observed a few test case failtures (because of section indices changes mostly it seems),
and a crash (seems we need to handle a case when there is no "Symbols:" key, but there is a SHT_SYMTAB described.
It wants to have a .strtab currently).
Shouldn't be too hard to fix, but if you do not mind, I'd also leave it for a one more independent follow-up.

test/Object/invalid.test

295

Yes, but [ ] shows the intention a bit better I think.

test/tools/yaml2obj/implicit-sections.test

88

I think the YAML term is mapping key, or key, not tag. Tag refers to a different thing (https://yaml.org/spec/1.2/spec.html#id2764295).

Seems might want to fix another comments we already have :)

[MaskRay]

lib/ObjectYAML/ELFEmitter.cpp

209–210

All points look good. We can do 1 and 2 in this patch. We can defer 3 to a future change.

tools/obj2yaml/elf2yaml.cpp

205

Y->Symbols.emplace();

[rupprecht]

Generally LGTM, although I think Ray is a much better person to approve this.

lib/ObjectYAML/ELFEmitter.cpp

209–210

For SHT_GROUP and SHT_SYMTAB_SHNDX, we don't have implicit sh_link = .symtab rule.

I'm not sure I understand this bit. Why not? According to my link, sh_link for those is "The section header index of the associated symbol table" -- is there a reference saying otherwise? (Not saying you're wrong, just looking for clarification).

231

SGTM, no rush

test/tools/llvm-objcopy/ELF/add-symbol-new-symbol-visibility.test

18–20

Hopefully you can revert these files after rL375105

[grimar]

lib/ObjectYAML/ELFEmitter.cpp

209–210

I'm not sure I understand this bit. Why not? According to my link, ...

Yeah, the link is correct. But we just do not implicity set sh_link to anything in yaml2obj for SHT_GROUP and SHT_SYMTAB_SHNDX yet.
(In compare with SHT_LLVM_ADDRSIG , for example, where we do). We might want to implement it, it is just a missing I think.

test/tools/llvm-objcopy/ELF/add-symbol-new-symbol-visibility.test

18–20

Yes. The latest diff does not have these lines anymore.

[grimar]

• Addressed review comment (push_back -> emplace).

include/llvm/ObjectYAML/ELFYAML.h

 struct Object {
   FileHeader Header;
   std::vector<ProgramHeader> ProgramHeaders;
   std::vector<std::unique_ptr<Section>> Sections;
   // Although in reality the symbols reside in a section, it is a lot
   // cleaner and nicer if we read them from the YAML as a separate
   // top-level key, which automatically ensures that invariants like there
   // being a single SHT_SYMTAB section are upheld.
-  std::vector<Symbol> Symbols;
+  Optional<std::vector<Symbol>> Symbols;
   std::vector<Symbol> DynamicSymbols;
 };
 
 } // end namespace ELFYAML
 } // end namespace llvm
 
 LLVM_YAML_IS_SEQUENCE_VECTOR(llvm::ELFYAML::AddrsigSymbol)
 LLVM_YAML_IS_SEQUENCE_VECTOR(llvm::ELFYAML::StackSizeEntry)

lib/ObjectYAML/ELFEmitter.cpp

 }
 
 template <class T> static void zero(T &Obj) { memset(&Obj, 0, sizeof(Obj)); }
 
 template <class ELFT>
 ELFState<ELFT>::ELFState(ELFYAML::Object &D, yaml::ErrorHandler EH)
     : Doc(D), ErrHandler(EH) {
   StringSet<> DocSections;
-  for (std::unique_ptr<ELFYAML::Section> &D : Doc.Sections)
+  for (std::unique_ptr<ELFYAML::Section> &D : Doc.Sections) {
     if (!D->Name.empty())
       DocSections.insert(D->Name);
 
+    // Some sections wants to link to .symtab by default.
+    // That means we want to create the symbol table for them.
+    if (D->Type == llvm::ELF::SHT_REL || D->Type == llvm::ELF::SHT_RELA ||
+        D->Type == llvm::ELF::SHT_LLVM_ADDRSIG)
+      if (!Doc.Symbols && D->Link.empty())
+        Doc.Symbols = std::vector<ELFYAML::Symbol>();
+
+    // Also sections might refer to the symbol table explicitly via Link.
+    // In this case we also must provide it, even when the YAML document does
+    // not have the "Symbols" tag.
+    if (!Doc.Symbols && D->Link == ".symtab")
+      Doc.Symbols = std::vector<ELFYAML::Symbol>();
+  }
+
   // Insert SHT_NULL section implicitly when it is not defined in YAML.
   if (Doc.Sections.empty() || Doc.Sections.front()->Type != ELF::SHT_NULL)
     Doc.Sections.insert(
         Doc.Sections.begin(),
         std::make_unique<ELFYAML::Section>(
             ELFYAML::Section::SectionKind::RawContent, /*IsImplicit=*/true));
 
-  std::vector<StringRef> ImplicitSections = {".symtab", ".strtab", ".shstrtab"};
+  std::vector<StringRef> ImplicitSections;
+  if (Doc.Symbols) 
+    ImplicitSections.push_back(".symtab");
+  ImplicitSections.push_back(".strtab");
+  ImplicitSections.push_back(".shstrtab");
+
   if (!Doc.DynamicSymbols.empty())
     ImplicitSections.insert(ImplicitSections.end(), {".dynsym", ".dynstr"});
 
   // Insert placeholders for implicit sections that are not
   // defined explicitly in YAML.
   for (StringRef SecName : ImplicitSections) {
     if (DocSections.count(SecName))
       continue;

 
 template <class ELFT>
 void ELFState<ELFT>::initSymtabSectionHeader(Elf_Shdr &SHeader,
                                              SymtabType STType,
                                              ContiguousBlobAccumulator &CBA,
                                              ELFYAML::Section *YAMLSec) {
 
   bool IsStatic = STType == SymtabType::Static;
-  const auto &Symbols = IsStatic ? Doc.Symbols : Doc.DynamicSymbols;
+  ArrayRef<ELFYAML::Symbol> Symbols;
+  if (IsStatic && Doc.Symbols)
+    Symbols = *Doc.Symbols;
+  else if (!IsStatic)
+    Symbols = Doc.DynamicSymbols;
 
   ELFYAML::RawContentSection *RawSec =
       dyn_cast_or_null<ELFYAML::RawContentSection>(YAMLSec);
   if (RawSec && !Symbols.empty() && (RawSec->Content || RawSec->Size)) {
     if (RawSec->Content)
       reportError("cannot specify both `Content` and " +
                   (IsStatic ? Twine("`Symbols`") : Twine("`DynamicSymbols`")) +
                   " for symbol table section '" + RawSec->Name + "'");
template <class ELFT> void ELFState<ELFT>::buildSymbolIndexes() {
   auto Build = [this](ArrayRef<ELFYAML::Symbol> V, NameToIdxMap &Map) {
     for (size_t I = 0, S = V.size(); I < S; ++I) {
       const ELFYAML::Symbol &Sym = V[I];
       if (!Sym.Name.empty() && !Map.addName(Sym.Name, I + 1))
         reportError("repeated symbol name: '" + Sym.Name + "'");
     }
   };
 
-  Build(Doc.Symbols, SymN2I);
+  if (Doc.Symbols)
+    Build(*Doc.Symbols, SymN2I);
   Build(Doc.DynamicSymbols, DynSymN2I);
 }
 
 template <class ELFT> void ELFState<ELFT>::finalizeStrings() {
   // Add the regular symbol names to .strtab section.
-  for (const ELFYAML::Symbol &Sym : Doc.Symbols)
+  if (Doc.Symbols)
+    for (const ELFYAML::Symbol &Sym : *Doc.Symbols)
       DotStrtab.add(ELFYAML::dropUniqueSuffix(Sym.Name));
   DotStrtab.finalize();
 
   // Add the dynamic symbol names to .dynstr section.
   for (const ELFYAML::Symbol &Sym : Doc.DynamicSymbols)
     DotDynstr.add(ELFYAML::dropUniqueSuffix(Sym.Name));
 
   // SHT_GNU_verdef and SHT_GNU_verneed sections might also
   // add strings to .dynstr section.

test/Object/invalid.test

FileHeader:
   Data:    ELFDATA2LSB
   Type:    ET_REL
   Machine: EM_X86_64
 Sections:
   - Name:     .rela
     Type:     SHT_RELA
     ShOffset: 0x10000
 
-## Check that llvm-objdump reports an error when .shstrtab has a broken sh_offset
-## so large that sh_offset + sh_size overflows the platform address size type.
+## Check that llvm-objdump reports an error when we try to print symbols and
+## .shstrtab has a broken sh_offset so large that sh_offset + sh_size overflows the platform address size type.
 
 # RUN: yaml2obj %s --docnum=14 -o %t14
 # RUN: not llvm-readobj --symbols %t14 2>&1 | FileCheck -DFILE=%t14 --check-prefix=INVALID-SECTION-SIZE2 %s
 
 # INVALID-SECTION-SIZE2: error: '[[FILE]]': section [index 1] has a sh_offset (0xffffffff) + sh_size (0x27) that cannot be represented
 
 --- !ELF
 FileHeader:
   Class:   ELFCLASS64
   Data:    ELFDATA2LSB
   Type:    ET_REL
   Machine: EM_386
 Sections:
   - Name:     .shstrtab
     Type:     SHT_STRTAB
     ShOffset: 0xFFFFFFFF
+Symbols: []
 
 ## Check that llvm-readobj reports an error when trying to dump sections
 ## when the e_shnum field is broken (is greater than the actual number of sections).
 
 # RUN: yaml2obj %s --docnum=15 -o %t15
 # RUN: not llvm-readobj -S %t15 2>&1 | FileCheck --check-prefix=INVALID-SECTION-NUM %s
 
 # INVALID-SECTION-NUM: error: {{.*}}: section table goes past the end of file

 
 ## We report an error if the number of sections stored in sh_size
 ## is greater than UINT64_MAX / sizeof(Elf_Shdr) == 288230376151711743.
 ## Here we check that do not crash on a border value.
 
 # RUN: yaml2obj --docnum=26 %s -o %t26
 # RUN: not llvm-readobj -h %t26 2>&1 | FileCheck -DFILE=%t26 --check-prefix=INVALID-SEC-NUM1 %s
 
-# INVALID-SEC-NUM1: error: '[[FILE]]': invalid section header table offset (e_shoff = 0x78) or invalid number of sections specified in the first section header's sh_size field (0x3ffffffffffffff)
+# INVALID-SEC-NUM1: error: '[[FILE]]': invalid section header table offset (e_shoff = 0x58) or invalid number of sections specified in the first section header's sh_size field (0x3ffffffffffffff)
 
 --- !ELF
 FileHeader:
   Class:   ELFCLASS64
   Data:    ELFDATA2LSB
   Type:    ET_REL
   Machine: EM_X86_64
   SHNum:   0x0

test/tools/llvm-objcopy/ELF/add-section-remove.test

- Name:            .test2
     Type:            SHT_PROGBITS
     Flags:           [ SHF_ALLOC ]
     Content:        "DEADBEEF"
   - Name:            .test3
     Type:            SHT_PROGBITS
     Flags:           [ SHF_ALLOC ]
     Content:        "32323232"
 
-# CHECK: SectionHeaderCount: 7
+# CHECK: SectionHeaderCount: 6
 
 # CHECK: Name: .test1
 # CHECK: Name: .test3
-# CHECK: Name: .symtab
 # CHECK: Name: .strtab
 # CHECK: Name: .shstrtab
 # CHECK: Name: .test2
 # CHECK: SectionData (
 # CHECK-NEXT:   0000: 30303030
 # CHECK-NEXT: )

test/tools/llvm-objcopy/ELF/add-section.test

- Name:            .test2
     Type:            SHT_PROGBITS
     Flags:           [ SHF_ALLOC ]
     Content:        "DEADBEEF"
   - Name:            .test3
     Type:            SHT_PROGBITS
     Flags:           [ SHF_ALLOC ]
     Content:        "32323232"
 
-# CHECK: SectionHeaderCount: 7
+# CHECK: SectionHeaderCount: 6
 
 # CHECK: Name: .test1
 # CHECK: Name: .test3
-# CHECK: Name: .symtab
 # CHECK: Name: .strtab
 # CHECK: Name: .shstrtab
 # CHECK: Name: .test2
 # CHECK: SectionData (
 # CHECK-NEXT:   0000: DEADBEEF
 # CHECK-NEXT: )
 
 ## Test that llvm-objcopy produces an error if the file with section contents

test/tools/llvm-objcopy/ELF/add-symbol-new-symbol-visibility.test

 FileHeader:
   Class:   ELFCLASS64
   Data:    ELFDATA2LSB
   Type:    ET_REL
   Machine: EM_X86_64
 Sections:
   - Name: .text
     Type: SHT_PROGBITS
+## TODO: llvm-objcopy crashes without the following line.
+## i.e. it crashes when there is no symbol table in the input.
+Symbols: []
 
 # CHECK: PROTECTED {{.*}} symbol_protected
 # CHECK: HIDDEN {{.*}} symbol_hidden

test/tools/llvm-objcopy/ELF/add-symbol.test

Sections:
       - Section: .text
   - Type: PT_LOAD
     Flags: [ PF_R, PF_W ]
     VAddr: 0x2000
     PAddr: 0x2000
     Align: 0x1000
     Sections:
       - Section: .data
+## TODO: llvm-objcopy crashes without the following line.
+## i.e. it crashes when there is no symbol table in the input.
+Symbols: []
 
 # CHECK:      0: 00000000 0 NOTYPE LOCAL DEFAULT UND
 # CHECK-NEXT: 1: 00000001 0 NOTYPE GLOBAL DEFAULT ABS abs1
 # CHECK-NEXT: 2: 00000002 0 FUNC LOCAL HIDDEN ABS abs2
 # CHECK-NEXT: 3: 00000003 0 OBJECT GLOBAL DEFAULT ABS abs3
 # CHECK-NEXT: 4: 00000004 0 OBJECT GLOBAL PROTECTED ABS abs4
 # CHECK-NEXT: 5: 00000000 0 FILE GLOBAL DEFAULT ABS foo.cpp
 # CHECK-NEXT: 6: 00001000 0 SECTION GLOBAL DEFAULT 1

test/tools/llvm-objcopy/ELF/basic-only-section.test

FileHeader:
   Data:            ELFDATA2LSB
   Type:            ET_REL
   Machine:         EM_X86_64
 Sections:
   - Name:            .test
     Type:            SHT_PROGBITS
     Flags:           [ ]
 
-# CHECK: SectionHeaderCount: 5
+# CHECK: SectionHeaderCount: 3
 
 # CHECK:     Name: .test
-# CHECK:     Name: .symtab
-# CHECK:     Name: .strtab
 # CHECK:     Name: .shstrtab

test/tools/llvm-objcopy/ELF/explicit-keep-remove.test

 # RUN: yaml2obj %s > %t
 # RUN: llvm-objcopy -R=.test --keep-section=.test %t %t2
 # RUN: llvm-readobj --file-headers --sections %t2 | FileCheck %s
 
 !ELF
 FileHeader:
   Class:           ELFCLASS64
   Data:            ELFDATA2LSB
   Type:            ET_REL
   Machine:         EM_X86_64
 Sections:
   - Name:            .test
     Type:            SHT_PROGBITS
     Flags:           [ ]
 
-# CHECK: SectionHeaderCount: 5
+# CHECK: SectionHeaderCount: 4
 
 # CHECK:     Name: .test
-# CHECK:     Name: .symtab
 # CHECK:     Name: .strtab
 # CHECK:     Name: .shstrtab

test/tools/llvm-objcopy/ELF/explicit-only-section-remove.test

 # RUN: yaml2obj %s > %t
 # RUN: llvm-objcopy -R=.test --only-section=.test %t %t2
 # RUN: llvm-readobj --file-headers --sections %t2 | FileCheck %s
 
 !ELF
 FileHeader:
   Class:           ELFCLASS64
   Data:            ELFDATA2LSB
   Type:            ET_REL
   Machine:         EM_X86_64
 Sections:
   - Name:            .test
     Type:            SHT_PROGBITS
     Flags:           [ ]
 
-# CHECK: SectionHeaderCount: 5
+# CHECK: SectionHeaderCount: 3
 
 # CHECK:     Name: .test
-# CHECK:     Name: .symtab
-# CHECK:     Name: .strtab
 # CHECK:     Name: .shstrtab

test/tools/llvm-objcopy/ELF/invalid-e_shoff.test

 FileHeader:
   Class:   ELFCLASS64
   Data:    ELFDATA2LSB
   Type:    ET_EXEC
   Machine: EM_X86_64
 Sections:
   - Name: .foo
     Type: SHT_PROGBITS
+Symbols: []
 
 # CASE2: error: '[[INPUT]]': section header table goes past the end of the file: e_shoff = 0x40000000

test/tools/llvm-objcopy/ELF/keep-only-section.test

 Sections:
   - Name:            .test
     Type:            SHT_PROGBITS
   - Name:            .test2
     Type:            SHT_PROGBITS
   - Name:            .test3
     Type:            SHT_PROGBITS
 
-# CHECK: SectionHeaderCount: 6
+# CHECK: SectionHeaderCount: 4
 
 # CHECK:     Name: .test
 # CHECK:     Name: .test2
-# CHECK:     Name: .symtab
-# CHECK:     Name: .strtab
 # CHECK:     Name: .shstrtab
 
-# REGEX: SectionHeaderCount: 7
+# REGEX: SectionHeaderCount: 5
 
 # REGEX:     Name: .test
 # REGEX:     Name: .test2
 # REGEX:     Name: .test3
-# REGEX:     Name: .symtab
-# REGEX:     Name: .strtab
 # REGEX:     Name: .shstrtab

test/tools/llvm-objcopy/ELF/no-strip-all.test

FileHeader:
   Class:   ELFCLASS64
   Data:    ELFDATA2LSB
   Type:    ET_REL
   Machine: EM_X86_64
 Sections:
   - Name:  .alloc
     Type:  SHT_PROGBITS
     Flags: [ SHF_ALLOC ]
+Symbols: []
 
 # ALL: SectionHeaderCount: 3
 # ALL: Name: .alloc
 # ALL: Name: .shstrtab
 
 # NO-STRIP: SectionHeaderCount: 5
 # NO-STRIP: Name: .alloc
 # NO-STRIP: Name: .symtab
 # NO-STRIP: Name: .strtab
 # NO-STRIP: Name: .shstrtab

test/tools/llvm-objcopy/ELF/null-symbol.test

FileHeader:
   Machine:         EM_X86_64
 Sections:
   - Name:            .text
     Type:            SHT_PROGBITS
     Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
     Address:         0x1000
     AddressAlign:    0x0000000000000010
     Size:            8
+Symbols: []
 
 #CHECK: Symbols [
 #CHECK-NEXT:  Symbol {
 #CHECK-NEXT:    Name: (0)
 #CHECK-NEXT:    Value: 0x0
 #CHECK-NEXT:    Size: 0
 #CHECK-NEXT:    Binding: Local
 #CHECK-NEXT:    Type: None
 #CHECK-NEXT:    Other: 0
 #CHECK-NEXT:    Section: Undefined
 #CHECK-NEXT:  }

test/tools/llvm-objcopy/ELF/only-section-many.test

- Name:            .test1
     Flags:           [ ]
   - Name:            .test2
     Type:            SHT_PROGBITS
     Flags:           [ ]
   - Name:            .test3
     Type:            SHT_PROGBITS
     Flags:           [ ]
 
-# CHECK: SectionHeaderCount: 6
+# CHECK: SectionHeaderCount: 4
 
 # CHECK:     Name: .test1
 # CHECK:     Name: .test2
-# CHECK:     Name: .symtab
-# CHECK:     Name: .strtab
 # CHECK:     Name: .shstrtab

test/tools/llvm-objcopy/ELF/preserve-segment-contents-ehdr-phdrs.test

- Name: .keep_me
     Size: 0x10
 ProgramHeaders:
   - Type:     PT_LOAD
     Offset:   0
     FileSize: 176 # sizeof(Elf64_Ehdr) + 2 * sizeof(Elf64_Phdr)
   - Type:     PT_LOAD
     Sections:
       - Section: .keep_me
+Symbols: []

test/tools/llvm-objcopy/ELF/remove-section.test

- Name:            .test1
     Type:            SHT_PROGBITS
     Flags:           [ ]
   - Name:            .test2
     Type:            SHT_PROGBITS
     Flags:           [ ]
   - Name:            .test3
     Type:            SHT_PROGBITS
     Flags:           [ ]
+Symbols: []
 
 # CHECK: SectionHeaderCount: 6
 
 # CHECK: Sections [
 # CHECK:   Section {
 # CHECK:     Index: 0
 # CHECK:     Name:  (0)
 # CHECK:     Type: SHT_NULL (0x0)

test/tools/llvm-objcopy/ELF/rename-section-multiple.test

- Name:            .test3
     Type:            SHT_PROGBITS
     Flags:           [ SHF_ALLOC ]
     Content:        "abababab"
   - Name:            .test7
     Type:            SHT_PROGBITS
     Flags:           [ SHF_ALLOC ]
     Content:        "37373737"
 
-# CHECK: SectionHeaderCount: 7
+# CHECK: SectionHeaderCount: 6
 
 # CHECK: Name: .test2
 # CHECK: SectionData (
 # CHECK-NEXT:   0000: C3C3C3C3
 # CHECK-NEXT: )
 # CHECK: Name: .test4
 # CHECK: SectionData (
 # CHECK-NEXT:   0000: ABABABAB
 # CHECK-NEXT: )
 # CHECK: Name: .test7
 # CHECK: SectionData (
 # CHECK-NEXT:   0000: 37373737
 # CHECK-NEXT: )
-# CHECK: Name: .symtab
 # CHECK: Name: .strtab
 # CHECK: Name: .shstrtab

test/tools/llvm-objcopy/ELF/rename-section.test

FileHeader:
   Type:            ET_REL
   Machine:         EM_X86_64
 Sections:
   - Name:            .foo
     Type:            SHT_PROGBITS
     Flags:           [ SHF_ALLOC ]
     Content:        "c3c3c3c3"
 
-# CHECK: SectionHeaderCount: 5
+# CHECK: SectionHeaderCount: 4
 
 # CHECK: Name: .bar
 # CHECK: SectionData (
 # CHECK-NEXT:   0000: C3C3C3C3
 # CHECK-NEXT: )
-# CHECK: Name: .symtab
 # CHECK: Name: .strtab
 # CHECK: Name: .shstrtab
 
 #BAD-FORMAT: bad format for --rename-section: missing '='
 #MULTIPLE-RENAMES: multiple renames of section '.foo'

test/tools/llvm-objcopy/ELF/segment-shift-section-remove.test

- Type: PT_LOAD
     Sections:
       - Section: .text
   - Type: PT_LOAD
     Flags: [ PF_X, PF_R ]
     VAddr: 0x3000
     PAddr: 0x3000
     Sections:
       - Section: .text3
+## TODO: without the following line (i.e. without an empty symbol table),
+## llvm-objcopy adds an empty .strtab section. It doesn't look correct.
+Symbols: []
 
 #CHECK: SectionHeaderCount: 4
 
 # CHECK:           Sections [
 # CHECK-NEXT:        Section {
 # CHECK-NEXT:          Index: 0
 # CHECK-NEXT:          Name:  (0)
 # CHECK-NEXT:          Type: SHT_NULL (0x0)

test/tools/llvm-objcopy/ELF/segment-test-remove-section.test

- Name:            .text3
     Size:            4096
 ProgramHeaders:
   - Type: PT_LOAD
     Flags: [ PF_X, PF_R ]
     Sections:
       - Section: .text
       - Section: .text2
       - Section: .text3
+## TODO: without the following line (i.e. without an empty symbol table),
+## llvm-objcopy adds an empty .strtab section. It doesn't look correct.
+Symbols: []
 
 # Make sure that when we remove a section we overwrite it with zeros
 # DATA: {{^[^[:blank:]]+}} 00 00 00 00
 
 #CHECK: SectionHeaderCount: 4
 
 # CHECK: Sections [
 # CHECK:   Section {

test/tools/llvm-objcopy/ELF/shstrtab-optimize.test

 # RUN: yaml2obj %s > %t
 # RUN: llvm-objcopy %t %t2
 # RUN: llvm-readobj --sections %t2 | FileCheck %s
 
 ## Check we have the correct size of the .shstrtab section
 ## after the strings tail merge optimization.
 
 # CHECK:      Name: .shstrtab
 # CHECK-NEXT: Type: SHT_STRTAB
 # CHECK-NEXT: Flags [
 # CHECK-NEXT: ]
 # CHECK-NEXT: Address:
 # CHECK-NEXT: Offset:
-# CHECK-NEXT: Size: 36
+# CHECK-NEXT: Size: 28
 
 !ELF
 FileHeader:
   Class:           ELFCLASS64
   Data:            ELFDATA2LSB
   Type:            ET_REL
   Machine:         EM_X86_64
 Sections:
   - Name:            .bar
     Type:            SHT_PROGBITS
     Flags:           [ ]
   - Name:            .foo.bar
     Type:            SHT_PROGBITS
     Flags:           [ ]

test/tools/llvm-objcopy/ELF/strip-unneeded-remove-debug-keep-link.test

FileHeader:
   Machine:         EM_X86_64
 Sections:
   - Name:            .text
     Type:            SHT_PROGBITS
     Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
   - Name:            .debugfoo
     Type:            SHT_PROGBITS
 
-# CHECK: There are 6 section headers
+# CHECK: There are 5 section headers
 
 # CHECK:        [ 0]
 # CHECK-NEXT:   [ 1] .text
-# CHECK-NEXT:   [ 2] .symtab
-# CHECK-NEXT:   [ 3] .strtab
-# CHECK-NEXT:   [ 4] .shstrtab
-# CHECK-NEXT:   [ 5] .gnu_debuglink
+# CHECK-NEXT:   [ 2] .strtab
+# CHECK-NEXT:   [ 3] .shstrtab
+# CHECK-NEXT:   [ 4] .gnu_debuglink

test/tools/llvm-objcopy/ELF/strtab-optimize.test

 # CHECK-NEXT: Size: 8
 
 !ELF
 FileHeader:
   Class:           ELFCLASS64
   Data:            ELFDATA2LSB
   Type:            ET_REL
   Machine:         EM_X86_64
+## TODO: llvm-objcopy crashes without the following line.
+## i.e. it crashes when there is no symbol table in the input.
+Symbols: []

test/tools/llvm-objcopy/ELF/symtab-error-on-remove-strtab.test

 # RUN: yaml2obj %s > %t
 # RUN: not llvm-objcopy -R .strtab %t %t2 2>&1 >/dev/null | FileCheck %s --check-prefix=ERR1 -DINPUT=%t
 # RUN: cp %t %t3
 # RUN: not llvm-strip --no-strip-all -R .strtab %t3 2>&1 >/dev/null | FileCheck %s --check-prefix=ERR2 -DINPUT=%t3
 
 !ELF
 FileHeader:
   Class:           ELFCLASS64
   Data:            ELFDATA2LSB
   Type:            ET_REL
   Machine:         EM_X86_64
+Symbols: []
 
 # ERR1: error: '[[INPUT]]': string table '.strtab' cannot be removed because it is referenced by the symbol table '.symtab'
 # ERR2: error: '[[INPUT]]': string table '.strtab' cannot be removed because it is referenced by the symbol table '.symtab'
 
 # RUN: llvm-objcopy --allow-broken-links -R .strtab %t %t4
 # RUN: llvm-objdump --section-headers %t4 | FileCheck %s --check-prefix=SECTIONS --implicit-check-not=.strtab
 # RUN: cp %t %t5
 # RUN: llvm-strip --no-strip-all --allow-broken-links -R .strtab %t %t5
 # RUN: llvm-objdump --section-headers %t5 | FileCheck %s --check-prefix=SECTIONS --implicit-check-not=.strtab
 
 # SECTIONS: .symtab

test/tools/llvm-objdump/full-contents.test

Sections:
   - Name:            .empty-nobits
     Type:            SHT_NOBITS
     Address:         0x1050
     Flags:           [ SHF_ALLOC ]
   - Name:            .non-alloc
     Type:            SHT_PROGBITS
     Flags:           [ ]
     Content:         '11112222'
+Symbols: []

test/tools/llvm-readobj/check-output-order.test

FileHeader:
   Type:    ET_DYN
   Machine: EM_X86_64
 Sections:
   - Name:    .dynamic
     Type:    SHT_DYNAMIC
     Entries:
       - Tag: DT_NULL
         Value: 0
+Symbols: []
 ProgramHeaders:
   - Type: PT_DYNAMIC
     Sections:
       - Section: .dynamic

test/tools/llvm-readobj/elf-dynamic-malformed.test

FileHeader:
   Data:    ELFDATA2LSB
   Type:    ET_EXEC
   Machine: EM_X86_64
 Sections:
   - Name:    .dynamic
     Type:    SHT_DYNAMIC
     Address: 0x1000
     Content: "01234567"
+Symbols: []
 ProgramHeaders:
   - Type: PT_LOAD
     VAddr: 0x1000
     Sections:
       - Section: .dynamic
   - Type: PT_DYNAMIC
     VAddr: 0x1000
     Sections:
- Name:    .dynamic
     Type:    SHT_DYNAMIC
     Address: 0x1000
     EntSize: 0x2
     Entries:
       - Tag:   DT_DEBUG
         Value: 0
       - Tag:   DT_NULL
         Value: 0
+Symbols: []
 ProgramHeaders:
   - Type: PT_LOAD
     VAddr: 0x1000
     Sections:
       - Section: .dynamic
   - Type: PT_DYNAMIC
     VAddr: 0x1000
     Sections:
Entries:
       - Tag:   DT_SONAME
         Value: 1
       - Tag:   DT_RPATH
         Value: 1
       - Tag:   DT_RUNPATH
         Value: 1
       - Tag:   DT_NULL
         Value: 0
+Symbols: []
 ProgramHeaders:
   - Type: PT_LOAD
     VAddr: 0x1000
     Sections:
       - Section: .dynstr
       - Section: .dynamic
   - Type: PT_DYNAMIC
     VAddr: 0x1010
Entries:
       - Tag:   DT_STRTAB
         Value: 0x2000000
       - Tag:   DT_STRSZ
         Value: 10
       - Tag:   DT_NEEDED
         Value: 1
       - Tag:   DT_NULL
         Value: 0x0
+Symbols: []
 ProgramHeaders:
   - Type: PT_LOAD
     VAddr: 0x1000
     Sections:
       - Section: .dynamic
   - Type: PT_DYNAMIC
     VAddr: 0x1000
     Sections:
Sections:
   - Name:    .dynamic
     Type:    SHT_DYNAMIC
     Address: 0x1000
     Entries:
       - Tag:   DT_RELA
         Value: 0x1000000
       - Tag:   DT_NULL
         Value: 0x0
+Symbols: []
 ProgramHeaders:
   - Type: PT_LOAD
     VAddr: 0x1000
     Sections:
       - Section: .dynamic
   - Type: PT_DYNAMIC
     VAddr: 0x1000
     Sections:
       - Section: .dynamic

test/tools/llvm-readobj/elf-file-headers.test

 # I386-NEXT:    ABIVersion: 0
 # I386-NEXT:    Unused: (00 00 00 00 00 00 00)
 # I386-NEXT:  }
 # I386-NEXT:  Type: Relocatable (0x1)
 # I386-NEXT:  Machine: EM_386 (0x3)
 # I386-NEXT:  Version: 1
 # I386-NEXT:  Entry: 0x0
 # I386-NEXT:  ProgramHeaderOffset: 0x0
-# I386-NEXT:  SectionHeaderOffset: 0x64
+# I386-NEXT:  SectionHeaderOffset: 0x48
 # I386-NEXT:  Flags [ (0x0)
 # I386-NEXT:  ]
 # I386-NEXT:  HeaderSize: 52
 # I386-NEXT:  ProgramHeaderEntrySize: 0
 # I386-NEXT:  ProgramHeaderCount: 0
 # I386-NEXT:  SectionHeaderEntrySize: 40
-# I386-NEXT:  SectionHeaderCount: 4
-# I386-NEXT:  StringTableSectionIndex: 3
+# I386-NEXT:  SectionHeaderCount: 3
+# I386-NEXT:  StringTableSectionIndex: 2
 # I386-NEXT:}
 # I386-NOT:{{.}}
 
 --- !ELF
 FileHeader:
   Class:   ELFCLASS32
   Data:    ELFDATA2LSB
   OSABI:   ELFOSABI_GNU

 # X86-64-NEXT:    ABIVersion: 0
 # X86-64-NEXT:    Unused: (00 00 00 00 00 00 00)
 # X86-64-NEXT:  }
 # X86-64-NEXT:  Type: Relocatable (0x1)
 # X86-64-NEXT:  Machine: EM_X86_64 (0x3E)
 # X86-64-NEXT:  Version: 1
 # X86-64-NEXT:  Entry: 0x0
 # X86-64-NEXT:  ProgramHeaderOffset: 0x0
-# X86-64-NEXT:  SectionHeaderOffset: 0x78
+# X86-64-NEXT:  SectionHeaderOffset: 0x58
 # X86-64-NEXT:  Flags [ (0x0)
 # X86-64-NEXT:  ]
 # X86-64-NEXT:  HeaderSize: 64
 # X86-64-NEXT:  ProgramHeaderEntrySize: 0
 # X86-64-NEXT:  ProgramHeaderCount: 0
 # X86-64-NEXT:  SectionHeaderEntrySize: 64
-# X86-64-NEXT:  SectionHeaderCount: 4
-# X86-64-NEXT:  StringTableSectionIndex: 3
+# X86-64-NEXT:  SectionHeaderCount: 3
+# X86-64-NEXT:  StringTableSectionIndex: 2
 # X86-64-NEXT:}
 # X86-64-NOT:{{.}}
 
 --- !ELF
 FileHeader:
   Class:   ELFCLASS64
   Data:    ELFDATA2LSB
   OSABI:   ELFOSABI_GNU

 # LANAI-NEXT:    ABIVersion: 0
 # LANAI-NEXT:    Unused: (00 00 00 00 00 00 00)
 # LANAI-NEXT:  }
 # LANAI-NEXT:  Type: Relocatable (0x1)
 # LANAI-NEXT:  Machine: EM_LANAI (0xF4)
 # LANAI-NEXT:  Version: 1
 # LANAI-NEXT:  Entry: 0x0
 # LANAI-NEXT:  ProgramHeaderOffset: 0x0
-# LANAI-NEXT:  SectionHeaderOffset: 0x64
+# LANAI-NEXT:  SectionHeaderOffset: 0x48
 # LANAI-NEXT:  Flags [ (0x0)
 # LANAI-NEXT:  ]
 # LANAI-NEXT:  HeaderSize: 52
 # LANAI-NEXT:  ProgramHeaderEntrySize: 0
 # LANAI-NEXT:  ProgramHeaderCount: 0
 # LANAI-NEXT:  SectionHeaderEntrySize: 40
-# LANAI-NEXT:  SectionHeaderCount: 4
-# LANAI-NEXT:  StringTableSectionIndex: 3
+# LANAI-NEXT:  SectionHeaderCount: 3
+# LANAI-NEXT:  StringTableSectionIndex: 2
 # LANAI-NEXT:}
 # LANAI-NOT:{{.}}

test/tools/llvm-readobj/elf-hidden-versym.test

 # RUN: yaml2obj %s -o %t
 # RUN: llvm-readelf -V %t | FileCheck %s --check-prefix=HIDDEN
 
 # HIDDEN:      Version symbols section '.gnu.version' contains 2 entries:
-# HIDDEN-NEXT:  Addr: 0000000000200210  Offset: 0x000040  Link: 6 (.dynsym)
+# HIDDEN-NEXT:  Addr: 0000000000200210  Offset: 0x000040  Link: 5 (.dynsym)
 # HIDDEN-NEXT:   000:   0 (*local*)       3h(hiddensym)
 
 --- !ELF
 FileHeader:
   Class:             ELFCLASS64
   Data:              ELFDATA2LSB
   Type:              ET_EXEC
   Machine:           EM_X86_64

test/tools/llvm-readobj/elf-invalid-shstrndx.test

 # RUN: yaml2obj %s -o %t
 # RUN: not llvm-readelf --headers -S 2>&1 %t | FileCheck %s -DFILE=%t --check-prefix=GNU
 # RUN: not llvm-readobj --headers -S 2>&1 %t | FileCheck %s -DFILE=%t --check-prefix=LLVM
 
 # GNU:      ELF Header:
 # GNU:        Section header string table index: 255
-# GNU-NEXT:   There are 4 section headers, starting at offset 0x78:
+# GNU-NEXT:   There are 3 section headers, starting at offset 0x58:
 # GNU:      Section Headers:
 # GNU-NEXT:  [Nr] Name
 # GNU-EMPTY:
 # GNU-NEXT:  error: '[[FILE]]': section header string table index 255 does not exist
 
 # LLVM:      ElfHeader {
 # LLVM:        StringTableSectionIndex: 255
 # LLVM-NEXT: }

test/tools/llvm-readobj/elf-invalid-versioning.test

 # RUN: yaml2obj %s -o %t
 # RUN: llvm-readelf -V %t | FileCheck %s --check-prefix=INVALID
 
 # INVALID:      Version symbols section '.gnu.version' contains 2 entries:
-# INVALID-NEXT:  Addr: 0000000000200210  Offset: 0x000040  Link: 6 (.dynsym)
+# INVALID-NEXT:  Addr: 0000000000200210  Offset: 0x000040  Link: 5 (.dynsym)
 # INVALID-NEXT:   000:   0 (*local*)       3 (*invalid*)
 
 --- !ELF
 FileHeader:
   Class:             ELFCLASS64
   Data:              ELFDATA2LSB
   Type:              ET_EXEC
   Machine:           EM_X86_64

test/tools/llvm-readobj/elf-no-phdrs.test

 # Show that llvm-readobj can handle no program headers when --program-headers
 # is requested, both for LLVM and GNU output.
 
 # RUN: yaml2obj %s -o %t
 # RUN: llvm-readobj %t --program-headers | FileCheck %s --check-prefix=LLVM
 # RUN: llvm-readelf %t --program-headers | FileCheck %s --check-prefix=GNU
 
 # LLVM:      ProgramHeaders [
 # LLVM-NEXT: ]
 
 # GNU:       There are 0 program headers
 # GNU:       Program Headers:
 # GNU-NEXT:    Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
 # GNU-EMPTY:
 # GNU-NEXT:  Section to Segment mapping:
 # GNU-NEXT:    Segment Sections...
-# GNU-NEXT:     None   .symtab .strtab .shstrtab
+# GNU-NEXT:     None   .strtab .shstrtab
 
 --- !ELF
 FileHeader:
   Class:   ELFCLASS64
   Data:    ELFDATA2LSB
   Type:    ET_REL
   Machine: EM_X86_64

test/tools/llvm-readobj/elf-versioninfo.test

 # LLVM-NEXT:         Index: 6
 # LLVM-NEXT:         Name: v3
 # LLVM-NEXT:       }
 # LLVM-NEXT:     ]
 # LLVM-NEXT:   }
 # LLVM-NEXT: }
 
 # GNU:      Version symbols section '.gnu.version' contains 6 entries:
-# GNU-NEXT:  Addr: 0000000000000000  Offset: 0x000040  Link: 7 (.dynsym)
+# GNU-NEXT:  Addr: 0000000000000000  Offset: 0x000040  Link: 6 (.dynsym)
 # GNU-NEXT:   000:   0 (*local*) 2 (VERSION1) 3 (VERSION2) 4 (v1)
 # GNU-NEXT:   004:   5 (v2)      6 (v3)
 # GNU-EMPTY:
 # GNU-NEXT: Version definition section '.gnu.version_d' contains 3 entries:
-# GNU-NEXT:  Addr: 0000000000000000  Offset: 0x00004c  Link: 8 (.dynstr)
+# GNU-NEXT:  Addr: 0000000000000000  Offset: 0x00004c  Link: 7 (.dynstr)
 # GNU-NEXT:   0x0000: Rev: 1  Flags: none  Index: 2  Cnt: 1  Name: VERSION1
 # GNU-NEXT:   0x001c: Rev: 1  Flags: none  Index: 3  Cnt: 2  Name: VERSION2
 # GNU-NEXT:   0x0038: Parent 1: VERSION1
 # GNU-NEXT:   0x001c: Rev: 1  Flags: none  Index: 3  Cnt: 2  Name: VERSION2
 # GNU-NEXT:   0x0038: Parent 1: VERSION1
 # GNU-EMPTY:
 # GNU-NEXT: Version needs section '.gnu.version_r' contains 2 entries:
-# GNU-NEXT:  Addr: 0000000000000000  Offset: 0x00008c  Link: 8 (.dynstr)
+# GNU-NEXT:  Addr: 0000000000000000  Offset: 0x00008c  Link: 7 (.dynstr)
 # GNU-NEXT:   0x0000: Version: 1  File: verneed1.so.0  Cnt: 2
 # GNU-NEXT:   0x0010:   Name: v1  Flags: none  Version: 4
 # GNU-NEXT:   0x0020:   Name: v2  Flags: none  Version: 5
 # GNU-NEXT:   0x0030: Version: 1  File: verneed2.so.0  Cnt: 1
 # GNU-NEXT:   0x0040:   Name: v3  Flags: none  Version: 6

test/tools/llvm-readobj/elf-wrong-shstrtab-type.test

 # LLVM: warning: '[[FILE]]': invalid sh_type for string table section [index 1]: expected SHT_STRTAB, but got SHT_PROGBITS
 # LLVM:  Section {
 # LLVM:    Name: .shstrtab
 # LLVM:    Type: SHT_PROGBITS
 
 # GNU: Section Headers:
 # GNU:   [Nr] Name              Type            Address          Off    Size   ES Flg Lk Inf Al
 # GNU: warning: '[[FILE]]': invalid sh_type for string table section [index 1]: expected SHT_STRTAB, but got SHT_PROGBITS
-# GNU:   [ 1] .shstrtab         PROGBITS        0000000000000000 000040 00001b 00 0   0  0
+# GNU:   [ 1] .shstrtab         PROGBITS        0000000000000000 000040 000013 00 0   0  0
 
 ## Test we report multiple identical warnings (one for each object) when dumping an archive.
 
 # RUN: rm -f %t.a
 # RUN: cp %t1 %t2
 # RUN: llvm-ar rc %t.a %t1 %t2 %t1
 # RUN: llvm-readobj -S %t.a 2>&1 | FileCheck %s --implicit-check-not warning --check-prefix WARNINGS
 # RUN: llvm-readelf -S %t.a 2>&1 | FileCheck %s --implicit-check-not warning --check-prefix WARNINGS

test/tools/obj2yaml/elf-no-symtab.yaml

+## Check that obj2yaml doesn't create a "Symbols" tag for the objects
+## without a symbol table.
+
+# RUN: yaml2obj --docnum=1 %s -o %t1
+# RUN: obj2yaml %t1 | FileCheck %s --check-prefix=NOSYMTAB
+
+# NOSYMTAB:      --- !ELF
+# NOSYMTAB-NEXT:  FileHeader:
+# NOSYMTAB-NEXT:    Class:           ELFCLASS64
+# NOSYMTAB-NEXT:    Data:            ELFDATA2LSB
+# NOSYMTAB-NEXT:    Type:            ET_DYN
+# NOSYMTAB-NEXT:    Machine:         EM_X86_64
+# NOSYMTAB-NEXT: ...
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_DYN
+  Machine: EM_X86_64
+
+## Check that obj2yaml creates a "Symbols" tag for the objects
+## that have a symbol table.
+
+# RUN: yaml2obj --docnum=2 %s -o %t2
+# RUN: obj2yaml %t2 | FileCheck %s --check-prefix=SYMTAB
+
+# SYMTAB:      --- !ELF
+# SYMTAB-NEXT:  FileHeader:
+# SYMTAB-NEXT:   Class:   ELFCLASS64
+# SYMTAB-NEXT:   Data:    ELFDATA2LSB
+# SYMTAB-NEXT:   Type:    ET_DYN
+# SYMTAB-NEXT:   Machine: EM_X86_64
+# SYMTAB-NEXT:  Symbols: []
+# SYMTAB-NEXT: ...
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_DYN
+  Machine: EM_X86_64
+Symbols: []

test/tools/obj2yaml/no-symbol-reloc.test

 # CHECK-NEXT:     Info:    .text
 # CHECK-NEXT:     Relocations:
 # CHECK-NEXT:       - Offset: 0x0000000000000000
 # CHECK-NEXT:         Symbol: ''
 # CHECK-NEXT:         Type:   R_X86_64_NONE
 # CHECK-NEXT:       - Offset: 0x0000000000000004
 # CHECK-NEXT:         Symbol: ''
 # CHECK-NEXT:         Type:   R_X86_64_NONE
+# CHECK-NEXT: Symbols: []
 # CHECK-NEXT: ...
 
 --- !ELF
 FileHeader:
   Class:   ELFCLASS64
   Data:    ELFDATA2LSB
   Type:    ET_REL
   Machine: EM_X86_64

test/tools/yaml2obj/dynamic-symbols.yaml

 # RUN: not llvm-readobj --dyn-symbols %t2 2>&1 | FileCheck -DFILE=%t2 %s --check-prefix=NUM
 
 # NUM:      Name: foo
 # NUM:      Section:
 # NUM-SAME: .data (0x1)
 
 # NUM:      Name: bar
 # NUM:      Section: 
-# NUM-SAME: .symtab (0x2)
+# NUM-SAME: .strtab (0x2)
 
 # NUM: error: '[[FILE]]': invalid section index: 255
 
 --- !ELF
 FileHeader:
   Class:   ELFCLASS64
   Data:    ELFDATA2LSB
   Type:    ET_DYN

test/tools/yaml2obj/elf-custom-null-section.yaml

 ## In this test we check that can redefine the null section in the YAML.
 
 ## Test the default output first.
 
 # RUN: yaml2obj --docnum=1 %s -o %t1
 # RUN: llvm-readelf --sections %t1 | FileCheck %s --check-prefix=DEFAULT
 
 # DEFAULT:      Section Headers:
 # DEFAULT-NEXT:  [Nr] Name      Type   Address          Off    Size   ES Flg Lk Inf Al
 # DEFAULT-NEXT:  [ 0]           NULL   0000000000000000 000000 000000 00 0   0  0
-# DEFAULT-NEXT:  [ 1] .symtab   SYMTAB 0000000000000000 000040 000018 18 2   1  8
-# DEFAULT-NEXT:  [ 2] .strtab   STRTAB 0000000000000000 000058 000001 00 0   0  1
-# DEFAULT-NEXT:  [ 3] .shstrtab STRTAB 0000000000000000 000059 00001b 00 0   0  1
+# DEFAULT-NEXT:  [ 1] .strtab   STRTAB 0000000000000000 000040 000001 00 0   0  1
+# DEFAULT-NEXT:  [ 2] .shstrtab STRTAB 0000000000000000 000041 000013 00 0   0  1
 
 --- !ELF
 FileHeader:
   Class:   ELFCLASS64
   Data:    ELFDATA2LSB
   Type:    ET_REL
   Machine: EM_X86_64
 

 
 # RUN: yaml2obj --docnum=5 %s -o %t5
 # RUN: llvm-readelf --sections %t5 | FileCheck %s --check-prefix=OTHER-SECTION
 
 # OTHER-SECTION:      Section Headers:
 # OTHER-SECTION-NEXT:   [Nr] Name      Type     Address          Off    Size   ES Flg Lk Inf Al
 # OTHER-SECTION-NEXT:   [ 0]           NULL     0000000000000000 000000 000000 00 0   0  0
 # OTHER-SECTION-NEXT:   [ 1] foo       PROGBITS 0000000000000000 000040 000000 00 0   0  0
-# OTHER-SECTION-NEXT:   [ 2] .symtab   SYMTAB   0000000000000000 000040 000018 18 3   1  8
-# OTHER-SECTION-NEXT:   [ 3] .strtab   STRTAB   0000000000000000 000058 000001 00 0   0  1
-# OTHER-SECTION-NEXT:   [ 4] .shstrtab STRTAB   0000000000000000 000059 00001f 00 0   0  1
+# OTHER-SECTION-NEXT:   [ 2] .strtab   STRTAB   0000000000000000 000040 000001 00 0   0  1
+# OTHER-SECTION-NEXT:   [ 3] .shstrtab STRTAB   0000000000000000 000041 000017 00 0   0  1
 
 --- !ELF
 FileHeader:
   Class:   ELFCLASS64
   Data:    ELFDATA2LSB
   Type:    ET_REL
   Machine: EM_X86_64
 Sections:

test/tools/yaml2obj/elf-header-sh-fields.yaml

 ## In this test case we check that we can override the default values for
 ## e_shentsize, e_shoff, e_shnum and e_shstrndx fields in the YAML.
 
 ## First we check the default values.
 
 # RUN: yaml2obj --docnum=1 %s -o %t1
 # RUN: llvm-readelf --file-headers %t1 | FileCheck %s --check-prefix=DEFAULT
 
-# DEFAULT:   Start of section headers:          120 (bytes into file)
+# DEFAULT:   Start of section headers:          88 (bytes into file)
 # DEFAULT:   Size of section headers:           64 (bytes)
-# DEFAULT:   Number of section headers:         4
-# DEFAULT:   Section header string table index: 3
+# DEFAULT:   Number of section headers:         3
+# DEFAULT:   Section header string table index: 2
 
 --- !ELF
 FileHeader:
   Class:   ELFCLASS64
   Data:    ELFDATA2LSB
   Type:    ET_REL
   Machine: EM_X86_64
 

test/tools/yaml2obj/implicit-sections-types.test

 # CASE1-NEXT: Type: SHT_STRTAB
 
 --- !ELF
 FileHeader:
   Class:   ELFCLASS64
   Data:    ELFDATA2LSB
   Type:    ET_DYN
   Machine: EM_X86_64
+## Needed to force the creation of the .symtab.
+Symbols:
 ## Needed to force the creation of the .dynsym and .dynstr.
 DynamicSymbols:
   - Name:    foo
   - Binding: STB_GLOBAL
 
 ## Check we can set any arbitrary types when describing sections
 ## that are usually implicit.
 

test/tools/yaml2obj/implicit-sections.test

- Name:    .symtab
     Type:    SHT_SYMTAB
   - Name:    .strtab
     Type:    SHT_STRTAB
   - Name:    .shstrtab
     Type:    SHT_STRTAB
   - Name:    .text.foo
     Type:    SHT_PROGBITS
     Address: 0x200
+
+## Check we don't add a symbol table when no "Symbols" tag is spicified.
+
+# RUN: yaml2obj --docnum=3 %s -o %t3
+# RUN: llvm-readelf -S %t3 | FileCheck %s --check-prefix=NOSYMTAB
+
+# NOSYMTAB-NOT: .symtab
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_DYN
+  Machine: EM_X86_64
+
+## Check we add a symbol table when "Symbols" tag is spicified.
+
+# RUN: yaml2obj --docnum=4 %s -o %t4
+# RUN: llvm-readelf -S %t4 | FileCheck %s --check-prefix=SYMTAB
+
+# SYMTAB: .symtab
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_DYN
+  Machine: EM_X86_64
+Symbols: []

test/tools/yaml2obj/symtab-implicit-sections-flags.yaml

 # CASE3-NEXT: ]
 
 --- !ELF
 FileHeader:
   Class:   ELFCLASS64
   Data:    ELFDATA2LSB
   Type:    ET_DYN
   Machine: EM_X86_64
+Symbols:

tools/obj2yaml/elf2yaml.cpp

if (!SymTab || SymTabShndx->sh_link != SymTab - Sections.begin())
           obj2yaml_error::not_implemented,
           "only SHT_SYMTAB_SHNDX associated with SHT_SYMTAB are supported");
 
     auto TableOrErr = Obj.getSHNDXTable(*SymTabShndx);
     if (!TableOrErr)
       return TableOrErr.takeError();
     ShndxTable = *TableOrErr;
   }
-  if (SymTab)
-    if (Error E = dumpSymbols(SymTab, Y->Symbols))
+
+  if (SymTab) {
+    Y->Symbols = std::vector<ELFYAML::Symbol>();
+    if (Error E = dumpSymbols(SymTab, *Y->Symbols))
       return std::move(E);
+  }
+
   if (DynSymTab)
     if (Error E = dumpSymbols(DynSymTab, Y->DynamicSymbols))
       return std::move(E);
 
   for (const Elf_Shdr &Sec : Sections) {
     switch (Sec.sh_type) {
     case ELF::SHT_DYNAMIC: {
       Expected<ELFYAML::DynamicSection *> SecOrErr = dumpDynamicSection(&Sec);