From 9afbac479f3d59929a50dcf7af9e99d70b45c6e7 Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Sun, 11 Oct 2015 20:19:20 +0000
Subject: [PATCH] Handle a crash in conflict detection with archive members.

llvm-svn: 249996
---
 lld/ELF/Config.h                      |  2 ++
 lld/ELF/InputFiles.h                  |  3 +++
 lld/ELF/SymbolTable.cpp               |  2 +-
 lld/test/elf2/incompatible-ar-first.s | 11 +++++++++++
 4 files changed, 17 insertions(+), 1 deletion(-)
 create mode 100644 lld/test/elf2/incompatible-ar-first.s

diff --git a/lld/ELF/Config.h b/lld/ELF/Config.h
index 021944a4c7b6..c19d136ffcea 100644
--- a/lld/ELF/Config.h
+++ b/lld/ELF/Config.h
@@ -18,6 +18,7 @@
 namespace lld {
 namespace elf2 {
 
+class ELFFileBase;
 class SymbolBody;
 
 enum ELFKind {
@@ -30,6 +31,7 @@ enum ELFKind {
 
 struct Configuration {
   SymbolBody *EntrySym = nullptr;
+  ELFFileBase *FirstElf = nullptr;
   llvm::StringRef DynamicLinker;
   llvm::StringRef Entry;
   llvm::StringRef Emulation;
diff --git a/lld/ELF/InputFiles.h b/lld/ELF/InputFiles.h
index 126ad3282339..488a76089415 100644
--- a/lld/ELF/InputFiles.h
+++ b/lld/ELF/InputFiles.h
@@ -249,6 +249,9 @@ std::unique_ptr<ELFFileBase> createELFFile(MemoryBufferRef MB) {
     error("Invalid file class: " + MB.getBufferIdentifier());
   }
 
+  if (!Config->FirstElf)
+    Config->FirstElf = Ret.get();
+
   if (Config->ElfKind == ELFNoneKind) {
     Config->ElfKind = Ret->getELFKind();
     Config->EMachine = Ret->getEMachine();
diff --git a/lld/ELF/SymbolTable.cpp b/lld/ELF/SymbolTable.cpp
index 3aff84d5bdd8..bfad8c333b31 100644
--- a/lld/ELF/SymbolTable.cpp
+++ b/lld/ELF/SymbolTable.cpp
@@ -35,7 +35,7 @@ void SymbolTable<ELFT>::addFile(std::unique_ptr<InputFile> File) {
       StringRef A = E->getName();
       StringRef B = Config->Emulation;
       if (B.empty())
-        B = getFirstELF()->getName();
+        B = Config->FirstElf->getName();
       error(A + " is incompatible with " + B);
     }
   }
diff --git a/lld/test/elf2/incompatible-ar-first.s b/lld/test/elf2/incompatible-ar-first.s
new file mode 100644
index 000000000000..f50f2c19fcd1
--- /dev/null
+++ b/lld/test/elf2/incompatible-ar-first.s
@@ -0,0 +1,11 @@
+// RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %p/Inputs/archive.s -o %ta.o
+// RUN: llvm-ar rc %t.a %ta.o
+// RUN: llvm-mc -filetype=obj -triple=i686-linux %s -o %tb.o
+// RUN: not ld.lld2 %t.a %tb.o 2>&1 | FileCheck %s
+
+// We used to crash when
+// * The first object seen by the symbol table is from an archive.
+// * -m was not used.
+// CHECK: a.o is incompatible with {{.*}}b.o
+
+// REQUIRES: x86