[llvm] r184627 - [yaml2obj][ELF] Make symbol table top-level key.
Sean Silva
silvas at purdue.edu
Fri Jun 21 18:38:01 PDT 2013
Author: silvas
Date: Fri Jun 21 20:38:00 2013
New Revision: 184627
URL: http://llvm.org/viewvc/llvm-project?rev=184627&view=rev
Log:
[yaml2obj][ELF] Make symbol table top-level key.
Although in reality the symbol table in ELF resides in a section, the
standard requires that there be no more than one SHT_SYMTAB. To enforce
this constraint, it is cleaner to group all the symbols under a
top-level `Symbols` key on the object file.
Modified:
llvm/trunk/include/llvm/Object/ELFYAML.h
llvm/trunk/lib/Object/ELFYAML.cpp
llvm/trunk/test/Object/yaml2obj-elf-symbol-LocalGlobalWeak.yaml
llvm/trunk/test/Object/yaml2obj-elf-symbol-basic.yaml
llvm/trunk/tools/yaml2obj/yaml2elf.cpp
Modified: llvm/trunk/include/llvm/Object/ELFYAML.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Object/ELFYAML.h?rev=184627&r1=184626&r2=184627&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Object/ELFYAML.h (original)
+++ llvm/trunk/include/llvm/Object/ELFYAML.h Fri Jun 21 20:38:00 2013
@@ -72,12 +72,15 @@ struct Section {
object::yaml::BinaryRef Content;
StringRef Link;
llvm::yaml::Hex64 AddressAlign;
- // For SHT_SYMTAB; should be empty otherwise.
- LocalGlobalWeakSymbols Symbols;
};
struct Object {
FileHeader Header;
std::vector<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.
+ LocalGlobalWeakSymbols Symbols;
};
} // end namespace ELFYAML
Modified: llvm/trunk/lib/Object/ELFYAML.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Object/ELFYAML.cpp?rev=184627&r1=184626&r2=184627&view=diff
==============================================================================
--- llvm/trunk/lib/Object/ELFYAML.cpp (original)
+++ llvm/trunk/lib/Object/ELFYAML.cpp Fri Jun 21 20:38:00 2013
@@ -244,7 +244,8 @@ void ScalarEnumerationTraits<ELFYAML::EL
#define ECase(X) IO.enumCase(Value, #X, ELF::X);
ECase(SHT_NULL)
ECase(SHT_PROGBITS)
- ECase(SHT_SYMTAB)
+ // No SHT_SYMTAB. Use the top-level `Symbols` key instead.
+ // FIXME: Issue a diagnostic with this information.
ECase(SHT_STRTAB)
ECase(SHT_RELA)
ECase(SHT_HASH)
@@ -326,17 +327,12 @@ void MappingTraits<ELFYAML::Section>::ma
IO.mapOptional("Content", Section.Content);
IO.mapOptional("Link", Section.Link);
IO.mapOptional("AddressAlign", Section.AddressAlign, Hex64(0));
- // TODO: Error if `Type` is SHT_SYMTAB and this is not present, or if
- // `Type` is *not* SHT_SYMTAB and this *is* present. (By SHT_SYMTAB I
- // also mean SHT_DYNSYM, but for simplicity right now we just do
- // SHT_SYMTAB). Want to be able to share the predicate with consumers of
- // this structure.
- IO.mapOptional("Symbols", Section.Symbols);
}
void MappingTraits<ELFYAML::Object>::mapping(IO &IO, ELFYAML::Object &Object) {
IO.mapRequired("FileHeader", Object.Header);
IO.mapOptional("Sections", Object.Sections);
+ IO.mapOptional("Symbols", Object.Symbols);
}
} // end namespace yaml
Modified: llvm/trunk/test/Object/yaml2obj-elf-symbol-LocalGlobalWeak.yaml
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Object/yaml2obj-elf-symbol-LocalGlobalWeak.yaml?rev=184627&r1=184626&r2=184627&view=diff
==============================================================================
--- llvm/trunk/test/Object/yaml2obj-elf-symbol-LocalGlobalWeak.yaml (original)
+++ llvm/trunk/test/Object/yaml2obj-elf-symbol-LocalGlobalWeak.yaml Fri Jun 21 20:38:00 2013
@@ -10,21 +10,19 @@ Sections:
Type: SHT_PROGBITS
Flags: [ SHF_ALLOC, SHF_WRITE ]
Content: "DEADBEEF"
- - Name: .symtab
- Type: SHT_SYMTAB
- Symbols:
- Local:
- - Name: local_symbol
- Type: STT_OBJECT
- Section: .data
- Global:
- - Name: global_symbol
- Type: STT_OBJECT
- Section: .data
- Weak:
- - Name: weak_symbol
- Type: STT_OBJECT
- Section: .data
+Symbols:
+ Local:
+ - Name: local_symbol
+ Type: STT_OBJECT
+ Section: .data
+ Global:
+ - Name: global_symbol
+ Type: STT_OBJECT
+ Section: .data
+ Weak:
+ - Name: weak_symbol
+ Type: STT_OBJECT
+ Section: .data
# CHECK: Symbol {
# CHECK: Name: (0)
Modified: llvm/trunk/test/Object/yaml2obj-elf-symbol-basic.yaml
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Object/yaml2obj-elf-symbol-basic.yaml?rev=184627&r1=184626&r2=184627&view=diff
==============================================================================
--- llvm/trunk/test/Object/yaml2obj-elf-symbol-basic.yaml (original)
+++ llvm/trunk/test/Object/yaml2obj-elf-symbol-basic.yaml Fri Jun 21 20:38:00 2013
@@ -16,16 +16,14 @@ Sections:
# This YAML file is a valid relocatable object that,
# when linked and run on x86_64, will go into an
# infloop.
- - Name: .symtab
- Type: SHT_SYMTAB
- Symbols:
- Global:
- - Name: main
- Type: STT_FUNC
- Section: .text
- Value: 0x1
- Size: 2
- - Name: undefined_symbol
+Symbols:
+ Global:
+ - Name: main
+ Type: STT_FUNC
+ Section: .text
+ Value: 0x1
+ Size: 2
+ - Name: undefined_symbol
# CHECK: Symbols [
# CHECK-NEXT: Symbol {
Modified: llvm/trunk/tools/yaml2obj/yaml2elf.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/yaml2obj/yaml2elf.cpp?rev=184627&r1=184626&r2=184627&view=diff
==============================================================================
--- llvm/trunk/tools/yaml2obj/yaml2elf.cpp (original)
+++ llvm/trunk/tools/yaml2obj/yaml2elf.cpp Fri Jun 21 20:38:00 2013
@@ -216,8 +216,7 @@ static void handleSymtabSectionHeader(
typename object::ELFObjectFile<ELFT>::Elf_Shdr &SHeader) {
typedef typename object::ELFObjectFile<ELFT>::Elf_Sym Elf_Sym;
- // TODO: Ensure that a manually specified `Link` field is diagnosed as an
- // error for SHT_SYMTAB.
+ SHeader.sh_type = ELF::SHT_SYMTAB;
SHeader.sh_link = State.getDotStrTabSecNo();
// One greater than symbol table index of the last local symbol.
SHeader.sh_info = Symbols.Local.size() + 1;
@@ -272,11 +271,12 @@ static int writeELF(raw_ostream &OS, con
// Immediately following the ELF header.
Header.e_shoff = sizeof(Header);
const std::vector<ELFYAML::Section> &Sections = Doc.Sections;
- // "+ 3" for
+ // "+ 4" for
// - SHT_NULL entry (placed first, i.e. 0'th entry)
+ // - symbol table (.symtab) (placed third to last)
// - string table (.strtab) (placed second to last)
// - section header string table. (placed last)
- Header.e_shnum = Sections.size() + 3;
+ Header.e_shnum = Sections.size() + 4;
// Place section header string table last.
Header.e_shstrndx = Header.e_shnum - 1;
const unsigned DotStrtabSecNo = Header.e_shnum - 2;
@@ -334,14 +334,16 @@ static int writeELF(raw_ostream &OS, con
SHeader.sh_info = 0;
SHeader.sh_addralign = Sec.AddressAlign;
SHeader.sh_entsize = 0;
- // XXX: Really ugly right now. Should not be writing to `CBA` above
- // (and setting sh_offset and sh_size) when going through this branch
- // here.
- if (Sec.Type == ELFYAML::ELF_SHT(SHT_SYMTAB))
- handleSymtabSectionHeader<ELFT>(Sec.Symbols, State, SHeader);
SHeaders.push_back(SHeader);
}
+ // .symtab section.
+ Elf_Shdr SymtabSHeader;
+ zero(SymtabSHeader);
+ SymtabSHeader.sh_name = SHStrTab.addString(StringRef(".symtab"));
+ handleSymtabSectionHeader<ELFT>(Doc.Symbols, State, SymtabSHeader);
+ SHeaders.push_back(SymtabSHeader);
+
// .strtab string table header.
Elf_Shdr DotStrTabSHeader;
zero(DotStrTabSHeader);
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