From 8aeb13fec137dc0e7d3d3599cc4224cf79d762b4 Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Thu, 3 Sep 2015 19:13:13 +0000
Subject: [PATCH] Add a helper function for getting the first object file.

Also preparation for shared objects. It will become the first ELF file.

llvm-svn: 246796
---
 lld/ELF/Driver.cpp      | 2 +-
 lld/ELF/SymbolTable.cpp | 7 +++----
 lld/ELF/SymbolTable.h   | 6 ++++++
 lld/ELF/Writer.cpp      | 2 +-
 4 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/lld/ELF/Driver.cpp b/lld/ELF/Driver.cpp
index 3f5b00b383b0..e7abc411f2b6 100644
--- a/lld/ELF/Driver.cpp
+++ b/lld/ELF/Driver.cpp
@@ -98,7 +98,7 @@ void LinkerDriver::link(ArrayRef<const char *> ArgsArr) {
   Symtab.reportRemainingUndefines();
 
   // Write the result.
-  ObjectFileBase &FirstObj = *Symtab.getObjectFiles()[0];
+  ObjectFileBase &FirstObj = *Symtab.getFirstObject();
   switch (FirstObj.getELFKind()) {
   case ELF32LEKind:
     writeResult<object::ELF32LE>(&Symtab);
diff --git a/lld/ELF/SymbolTable.cpp b/lld/ELF/SymbolTable.cpp
index 2d1b5c8f782a..5e9a1c9ffa83 100644
--- a/lld/ELF/SymbolTable.cpp
+++ b/lld/ELF/SymbolTable.cpp
@@ -33,10 +33,9 @@ template <class ELFT> void SymbolTable::init() {
 }
 
 void SymbolTable::addObject(ObjectFileBase *File) {
-  if (!ObjectFiles.empty()) {
-    ObjectFileBase &Old = *ObjectFiles[0];
-    if (!Old.isCompatibleWith(*File))
-      error(Twine(Old.getName() + " is incompatible with " + File->getName()));
+  if (const ObjectFileBase *Old = getFirstObject()) {
+    if (!Old->isCompatibleWith(*File))
+      error(Twine(Old->getName() + " is incompatible with " + File->getName()));
   } else {
     switch (File->getELFKind()) {
     case ELF32LEKind:
diff --git a/lld/ELF/SymbolTable.h b/lld/ELF/SymbolTable.h
index b4e50aa6438d..84fbe00be2b7 100644
--- a/lld/ELF/SymbolTable.h
+++ b/lld/ELF/SymbolTable.h
@@ -34,6 +34,12 @@ public:
 
   void addFile(std::unique_ptr<InputFile> File);
 
+  ObjectFileBase *getFirstObject() const {
+    if (!ObjectFiles.empty())
+      return ObjectFiles[0].get();
+    return nullptr;
+  }
+
   // Print an error message on undefined symbols.
   void reportRemainingUndefines();
 
diff --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp
index 970d6cdb9bcb..f49874295bb3 100644
--- a/lld/ELF/Writer.cpp
+++ b/lld/ELF/Writer.cpp
@@ -543,7 +543,7 @@ template <class ELFT> void Writer<ELFT>::writeHeader() {
 
   EHdr->e_type = ET_EXEC;
   const SymbolTable &Symtab = SymTable.getSymTable();
-  auto &FirstObj = cast<ObjectFile<ELFT>>(*Symtab.getObjectFiles()[0]);
+  auto &FirstObj = cast<ObjectFile<ELFT>>(*Symtab.getFirstObject());
   EHdr->e_machine = FirstObj.getObj()->getHeader()->e_machine;
   EHdr->e_version = EV_CURRENT;
   EHdr->e_entry = 0x401000;