commit 0e7ed91264c6502389f6ec0d36d9857c2d64b6d1
author George Rimar <grimar@accesssoftek.com> Sat Feb 09 11:34:28 2019 +0000
committer George Rimar <grimar@accesssoftek.com> Sat Feb 09 11:34:28 2019 +0000
tree 276a0fea5ea0a186473ef8f8ba34240426a29676
parent 283d103bde5bfdd59d9836e0c72ca7258df6cdd7

[yaml2obj][obj2yaml] - Add support for dumping/parsing .dynamic sections.

This teaches the tools to parse and dump
the .dynamic section and its dynamic tags.

Differential revision: https://reviews.llvm.org/D57691

llvm-svn: 353606

llvm/tools/obj2yaml/elf2yaml.cpp

diff --git a/llvm/tools/obj2yaml/elf2yaml.cpp b/llvm/tools/obj2yaml/elf2yaml.cpp
index e2fb463..a089890 100644
--- a/llvm/tools/obj2yaml/elf2yaml.cpp
+++ b/llvm/tools/obj2yaml/elf2yaml.cpp
@@ -21,6 +21,7 @@
 template <class ELFT>
 class ELFDumper {
   typedef object::Elf_Sym_Impl<ELFT> Elf_Sym;
+  typedef typename ELFT::Dyn Elf_Dyn;
   typedef typename ELFT::Shdr Elf_Shdr;
   typedef typename ELFT::Word Elf_Word;
   typedef typename ELFT::Rel Elf_Rel;
@@ -50,7 +51,8 @@
   template <class RelT>
   std::error_code dumpRelocation(const RelT *Rel, const Elf_Shdr *SymTab,
                                  ELFYAML::Relocation &R);
-
+  
+  ErrorOr<ELFYAML::DynamicSection *> dumpDynamicSection(const Elf_Shdr *Shdr);
   ErrorOr<ELFYAML::RelocationSection *> dumpRelocSection(const Elf_Shdr *Shdr);
   ErrorOr<ELFYAML::RawContentSection *>
   dumpContentSection(const Elf_Shdr *Shdr);
@@ -129,6 +131,13 @@
   SectionNames.resize(Sections.size());
   for (const Elf_Shdr &Sec : Sections) {
     switch (Sec.sh_type) {
+    case ELF::SHT_DYNAMIC: {
+      ErrorOr<ELFYAML::DynamicSection *> S = dumpDynamicSection(&Sec);
+      if (std::error_code EC = S.getError())
+        return EC;
+      Y->Sections.push_back(std::unique_ptr<ELFYAML::Section>(S.get()));
+      break;
+    }
     case ELF::SHT_NULL:
     case ELF::SHT_STRTAB:
       // Do not dump these sections.
@@ -351,6 +360,23 @@
 }
 
 template <class ELFT>
+ErrorOr<ELFYAML::DynamicSection *>
+ELFDumper<ELFT>::dumpDynamicSection(const Elf_Shdr *Shdr) {
+  auto S = make_unique<ELFYAML::DynamicSection>();
+  if (std::error_code EC = dumpCommonSection(Shdr, *S))
+    return EC;
+
+  auto DynTagsOrErr = Obj.template getSectionContentsAsArray<Elf_Dyn>(Shdr);
+  if (!DynTagsOrErr)
+    return errorToErrorCode(DynTagsOrErr.takeError());
+
+  for (const Elf_Dyn &Dyn : *DynTagsOrErr)
+    S->Entries.push_back({(ELFYAML::ELF_DYNTAG)Dyn.getTag(), Dyn.getVal()});
+
+  return S.release();
+}
+
+template <class ELFT>
 ErrorOr<ELFYAML::RelocationSection *>
 ELFDumper<ELFT>::dumpRelocSection(const Elf_Shdr *Shdr) {
   auto S = make_unique<ELFYAML::RelocationSection>();

llvm/tools/yaml2obj/yaml2elf.cpp

diff --git a/llvm/tools/yaml2obj/yaml2elf.cpp b/llvm/tools/yaml2obj/yaml2elf.cpp
index 0b2c99cc..4e3a1d7 100644
--- a/llvm/tools/yaml2obj/yaml2elf.cpp
+++ b/llvm/tools/yaml2obj/yaml2elf.cpp
@@ -159,6 +159,9 @@
   bool writeSectionContent(Elf_Shdr &SHeader,
                            const ELFYAML::MipsABIFlags &Section,
                            ContiguousBlobAccumulator &CBA);
+  void writeSectionContent(Elf_Shdr &SHeader,
+                           const ELFYAML::DynamicSection &Section,
+                           ContiguousBlobAccumulator &CBA);
   bool hasDynamicSymbols() const;
   SmallVector<const char *, 5> implicitSectionNames() const;
 
@@ -291,6 +294,8 @@
       // SHT_NOBITS section does not have content
       // so just to setup the section offset.
       CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
+    } else if (auto S = dyn_cast<ELFYAML::DynamicSection>(Sec.get())) {
+      writeSectionContent(SHeader, *S, CBA);
     } else
       llvm_unreachable("Unknown section type");
 
@@ -465,8 +470,6 @@
     SHeader.sh_entsize = *Section.EntSize;
   else if (Section.Type == llvm::ELF::SHT_RELR)
     SHeader.sh_entsize = sizeof(Elf_Relr);
-  else if (Section.Type == llvm::ELF::SHT_DYNAMIC)
-    SHeader.sh_entsize = sizeof(Elf_Dyn);
   else
     SHeader.sh_entsize = 0;
   SHeader.sh_size = Section.Size;
@@ -575,6 +578,29 @@
   return true;
 }
 
+template <class ELFT>
+void ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
+                                         const ELFYAML::DynamicSection &Section,
+                                         ContiguousBlobAccumulator &CBA) {
+  typedef typename ELFT::uint uintX_t;
+  assert(Section.Type == llvm::ELF::SHT_DYNAMIC &&
+         "Section type is not SHT_DYNAMIC");
+
+  SHeader.sh_size = 2 * sizeof(uintX_t) * Section.Entries.size();
+  if (Section.EntSize)
+    SHeader.sh_entsize = *Section.EntSize;
+  else
+    SHeader.sh_entsize = sizeof(Elf_Dyn);
+
+  auto &OS = CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
+  for (const ELFYAML::DynamicEntry &DE : Section.Entries) {
+    uintX_t Tag = DE.Tag;
+    OS.write((const char *)&Tag, sizeof(uintX_t));
+    uintX_t Val = DE.Val;
+    OS.write((const char *)&Val, sizeof(uintX_t));
+  }
+}
+
 template <class ELFT> bool ELFState<ELFT>::buildSectionIndex() {
   for (unsigned i = 0, e = Doc.Sections.size(); i != e; ++i) {
     StringRef Name = Doc.Sections[i]->Name;