[yaml2obj/obj2yaml] - Add support for SHT_LLVM_ADDRSIG sections.

SHT_LLVM_ADDRSIG is described here:
https://llvm.org/docs/Extensions.html#sht-llvm-addrsig-section-address-significance-table

This patch teaches tools to dump them and to parse the YAML declarations of such sections.

Differential revision: https://reviews.llvm.org/D68333

llvm-svn: 373598

1 files changed, 30 insertions, 0 deletions

diff --git a/llvm/lib/ObjectYAML/ELFEmitter.cpp b/llvm/lib/ObjectYAML/ELFEmitter.cpp
index c85cf4c924f..3f3b27c5bfa 100644
--- a/llvm/lib/ObjectYAML/ELFEmitter.cpp
+++ b/llvm/lib/ObjectYAML/ELFEmitter.cpp
@@ -174,6 +174,10 @@ template <class ELFT> class ELFState {
   void writeSectionContent(Elf_Shdr &SHeader,
                            const ELFYAML::HashSection &Section,
                            ContiguousBlobAccumulator &CBA);
+  void writeSectionContent(Elf_Shdr &SHeader,
+                           const ELFYAML::AddrsigSection &Section,
+                           ContiguousBlobAccumulator &CBA);
+
   ELFState(ELFYAML::Object &D, yaml::ErrorHandler EH);
 
 public:
@@ -423,6 +427,8 @@ void ELFState<ELFT>::initSectionHeaders(std::vector<Elf_Shdr> &SHeaders,
       writeSectionContent(SHeader, *S, CBA);
     } else if (auto S = dyn_cast<ELFYAML::HashSection>(Sec)) {
       writeSectionContent(SHeader, *S, CBA);
+    } else if (auto S = dyn_cast<ELFYAML::AddrsigSection>(Sec)) {
+      writeSectionContent(SHeader, *S, CBA);
     } else {
       llvm_unreachable("Unknown section type");
     }
@@ -990,6 +996,30 @@ void ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
     Section.Content->writeAsBinary(OS);
 }
 
+template <class ELFT>
+void ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
+                                         const ELFYAML::AddrsigSection &Section,
+                                         ContiguousBlobAccumulator &CBA) {
+  raw_ostream &OS =
+      CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
+
+  unsigned Link = 0;
+  if (Section.Link.empty() && SN2I.lookup(".symtab", Link))
+    SHeader.sh_link = Link;
+
+  if (Section.Content) {
+    SHeader.sh_size = writeContent(OS, Section.Content, None);
+    return;
+  }
+
+  for (const ELFYAML::AddrsigSymbol &Sym : *Section.Symbols) {
+    uint64_t Val =
+        Sym.Name ? toSymbolIndex(*Sym.Name, Section.Name, /*IsDynamic=*/false)
+                 : (uint32_t)*Sym.Index;
+    SHeader.sh_size += encodeULEB128(Val, OS);
+  }
+}
+
 template <class ELFT> void ELFState<ELFT>::buildSectionIndex() {
   for (unsigned I = 0, E = Doc.Sections.size(); I != E; ++I) {
     StringRef Name = Doc.Sections[I]->Name;