Don't iterate over all sections in the ELFFile constructor.

With this we finally have an ELFFile that is O(1) to construct. This is helpful
for programs like lld which have to do their own section walk.

llvm-svn: 244510

1 files changed, 16 insertions, 7 deletions

diff --git a/llvm/tools/obj2yaml/elf2yaml.cpp b/llvm/tools/obj2yaml/elf2yaml.cpp
index 214148d41b8..6aea437aba7 100644
--- a/llvm/tools/obj2yaml/elf2yaml.cpp
+++ b/llvm/tools/obj2yaml/elf2yaml.cpp
@@ -26,9 +26,10 @@ class ELFDumper {
   typedef typename object::ELFFile<ELFT>::Elf_Word Elf_Word;
 
   const object::ELFFile<ELFT> &Obj;
+  ArrayRef<Elf_Word> ShndxTable;
 
-  std::error_code dumpSymbol(const Elf_Sym *Sym, StringRef StrTable,
-                             ELFYAML::Symbol &S);
+  std::error_code dumpSymbol(const Elf_Sym *Sym, const Elf_Shdr *SymTab,
+                             StringRef StrTable, ELFYAML::Symbol &S);
   std::error_code dumpCommonSection(const Elf_Shdr *Shdr, ELFYAML::Section &S);
   std::error_code dumpCommonRelocationSection(const Elf_Shdr *Shdr,
                                               ELFYAML::RelocationSection &S);
@@ -81,6 +82,13 @@ ErrorOr<ELFYAML::Object *> ELFDumper<ELFT>::dump() {
     case ELF::SHT_SYMTAB:
       Symtab = &Sec;
       break;
+    case ELF::SHT_SYMTAB_SHNDX: {
+      ErrorOr<ArrayRef<Elf_Word>> TableOrErr = Obj.getSHNDXTable(Sec);
+      if (std::error_code EC = TableOrErr.getError())
+        return EC;
+      ShndxTable = *TableOrErr;
+      break;
+    }
     case ELF::SHT_RELA: {
       ErrorOr<ELFYAML::RelocationSection *> S = dumpRelaSection(&Sec);
       if (std::error_code EC = S.getError())
@@ -139,7 +147,8 @@ ErrorOr<ELFYAML::Object *> ELFDumper<ELFT>::dump() {
     }
 
     ELFYAML::Symbol S;
-    if (std::error_code EC = ELFDumper<ELFT>::dumpSymbol(&Sym, StrTable, S))
+    if (std::error_code EC =
+            ELFDumper<ELFT>::dumpSymbol(&Sym, Symtab, StrTable, S))
       return EC;
 
     switch (Sym.getBinding())
@@ -162,9 +171,9 @@ ErrorOr<ELFYAML::Object *> ELFDumper<ELFT>::dump() {
 }
 
 template <class ELFT>
-std::error_code ELFDumper<ELFT>::dumpSymbol(const Elf_Sym *Sym,
-                                            StringRef StrTable,
-                                            ELFYAML::Symbol &S) {
+std::error_code
+ELFDumper<ELFT>::dumpSymbol(const Elf_Sym *Sym, const Elf_Shdr *SymTab,
+                            StringRef StrTable, ELFYAML::Symbol &S) {
   S.Type = Sym->getType();
   S.Value = Sym->st_value;
   S.Size = Sym->st_size;
@@ -175,7 +184,7 @@ std::error_code ELFDumper<ELFT>::dumpSymbol(const Elf_Sym *Sym,
     return EC;
   S.Name = NameOrErr.get();
 
-  ErrorOr<const Elf_Shdr *> ShdrOrErr = Obj.getSection(Sym);
+  ErrorOr<const Elf_Shdr *> ShdrOrErr = Obj.getSection(Sym, SymTab, ShndxTable);
   if (std::error_code EC = ShdrOrErr.getError())
     return EC;
   const Elf_Shdr *Shdr = *ShdrOrErr;