Return ErrorOr from getSymbolAddress.

It can fail trying to get the section on ELF and COFF. This makes sure the
error is handled.

llvm-svn: 241366
diff --git a/llvm/lib/Object/Object.cpp b/llvm/lib/Object/Object.cpp
index 945252b..c7d91bc 100644
--- a/llvm/lib/Object/Object.cpp
+++ b/llvm/lib/Object/Object.cpp
@@ -180,10 +180,10 @@
 }
 
 uint64_t LLVMGetSymbolAddress(LLVMSymbolIteratorRef SI) {
-  uint64_t ret;
-  if (std::error_code ec = (*unwrap(SI))->getAddress(ret))
-    report_fatal_error(ec.message());
-  return ret;
+  ErrorOr<uint64_t> Ret = (*unwrap(SI))->getAddress();
+  if (std::error_code EC = Ret.getError())
+    report_fatal_error(EC.message());
+  return *Ret;
 }
 
 uint64_t LLVMGetSymbolSize(LLVMSymbolIteratorRef SI) {