[llvm-objdump] - Do not include reserved undefined symbol in -t output.

This is https://bugs.llvm.org/show_bug.cgi?id=26892,

GNU objdump hides the special symbol entry:

SYMBOL TABLE:
000000000000a7e0 l     F .text	00000000000003f9 bi_copymodules
while llvm-objdump does not:

SYMBOL TABLE:
0000000000000000         *UND*		 00000000 
000000000000a7e0 l     F .text		 000003f9 bi_copymodules

Patch makes the behavior of the llvm-objdump to be consistent with the GNU objdump.

Differential revision: https://reviews.llvm.org/D56076

llvm-svn: 350840

1 files changed, 8 insertions, 1 deletions

diff --git a/llvm/tools/llvm-objdump/llvm-objdump.cpp b/llvm/tools/llvm-objdump/llvm-objdump.cpp
index 21359a7..b68714e 100644
--- a/llvm/tools/llvm-objdump/llvm-objdump.cpp
+++ b/llvm/tools/llvm-objdump/llvm-objdump.cpp
@@ -2015,7 +2015,14 @@ void llvm::PrintSymbolTable(const ObjectFile *o, StringRef ArchiveName,
     printCOFFSymbolTable(coff);
     return;
   }
-  for (const SymbolRef &Symbol : o->symbols()) {
+
+  for (auto I = o->symbol_begin(), E = o->symbol_end(); I != E; ++I) {
+    // Skip printing the special zero symbol when dumping an ELF file.
+    // This makes the output consistent with the GNU objdump.
+    if (I == o->symbol_begin() && isa<ELFObjectFileBase>(o))
+      continue;
+
+    const SymbolRef &Symbol = *I;
     Expected<uint64_t> AddressOrError = Symbol.getAddress();
     if (!AddressOrError)
       report_error(ArchiveName, o->getFileName(), AddressOrError.takeError(),