[llvm-readobj] [COFF] Print the symbol index for relocations

There can be multiple local symbols with the same name (for e.g.
comdat sections), and thus the symbol name itself isn't enough
to disambiguate symbols.

Differential Revision: https://reviews.llvm.org/D56140

llvm-svn: 350288

1 files changed, 10 insertions, 0 deletions

diff --git a/llvm/lib/Object/COFFObjectFile.cpp b/llvm/lib/Object/COFFObjectFile.cpp
index e17f0e2783e..fc1deeba339 100644
--- a/llvm/lib/Object/COFFObjectFile.cpp
+++ b/llvm/lib/Object/COFFObjectFile.cpp
@@ -1065,6 +1065,16 @@ COFFObjectFile::getSymbolAuxData(COFFSymbolRef Symbol) const {
   return makeArrayRef(Aux, Symbol.getNumberOfAuxSymbols() * SymbolSize);
 }
 
+uint32_t COFFObjectFile::getSymbolIndex(COFFSymbolRef Symbol) const {
+  uintptr_t Offset =
+      reinterpret_cast<uintptr_t>(Symbol.getRawPtr()) - getSymbolTable();
+  assert(Offset % getSymbolTableEntrySize() == 0 &&
+         "Symbol did not point to the beginning of a symbol");
+  size_t Index = Offset / getSymbolTableEntrySize();
+  assert(Index < getNumberOfSymbols());
+  return Index;
+}
+
 std::error_code COFFObjectFile::getSectionName(const coff_section *Sec,
                                                StringRef &Res) const {
   StringRef Name;