From 4d7f70d47e027f5ba6d532cd4bd4f53014b9bd7a Mon Sep 17 00:00:00 2001
From: Juergen Ributzka <juergen@apple.com>
Date: Fri, 19 Dec 2014 02:31:01 +0000
Subject: [PATCH] [Object] Don't crash on empty export lists.

Summary: This fixes the exports iterator if the export list is empty.

Reviewers: Bigcheese, kledzik

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D6732

llvm-svn: 224563
---
 llvm/lib/Object/MachOObjectFile.cpp            |   5 ++++-
 llvm/test/Object/Inputs/macho-no-exports.dylib | Bin 0 -> 4208 bytes
 llvm/test/Object/objdump-export-list.test      |   4 ++++
 3 files changed, 8 insertions(+), 1 deletion(-)
 create mode 100755 llvm/test/Object/Inputs/macho-no-exports.dylib
 create mode 100644 llvm/test/Object/objdump-export-list.test

diff --git a/llvm/lib/Object/MachOObjectFile.cpp b/llvm/lib/Object/MachOObjectFile.cpp
index fd086af..92981fe 100644
--- a/llvm/lib/Object/MachOObjectFile.cpp
+++ b/llvm/lib/Object/MachOObjectFile.cpp
@@ -1640,7 +1640,10 @@ void ExportEntry::moveNext() {
 iterator_range<export_iterator> 
 MachOObjectFile::exports(ArrayRef<uint8_t> Trie) {
   ExportEntry Start(Trie);
-  Start.moveToFirst();
+  if (Trie.size() == 0)
+    Start.moveToEnd();
+  else
+    Start.moveToFirst();
 
   ExportEntry Finish(Trie);
   Finish.moveToEnd();
diff --git a/llvm/test/Object/Inputs/macho-no-exports.dylib b/llvm/test/Object/Inputs/macho-no-exports.dylib
new file mode 100755
index 0000000000000000000000000000000000000000..6e1be6ca97e67b5281475a295532847b3be69324
GIT binary patch
literal 4208
zcmeHLyGjF55IxbTA&FpNq1dR1_+S&eSXhV{*kBOB6lvsQ+(iTCL3RU4mqx$A+TO-e
z@Ds#8@DJ>)f{14}dy^0&SX$hHvpaL{%<Syx=Dv2{zh;2QB!FpRmar#)8_dxI7KuAT
zsY13`5N5=BX#+Bh*%MPlBs@{dcU%4-?MJ^~`t&QJ==6O$GM7y#mCqd?We;<DHr;3B
zT@Q<8E<KY_^1nO80@35;8A0Xz;;Lp<YnI!p*BZW;a@yDB60iz%B>%5QDTCfN=aJ4u
zzU5m9;)EDy!}E<hAIB|`l)m@*r<L2YjP-b#b3PtkKG(?clR!KkU`xls(UQb2A+<6q
z@Eny%(@n3D<{t}A+n(=MQU_WC$yz6ZzI?>!Z-#L!Ac5_nc%Qy8qkvJsC}0#Y3K#{9
z0!9I&fKk9GU=;Wt3UuF+vaatDdi|UyC&O)ooLmpcikKK$2^m7J4uS&~>RK#=3$vp<
PzgbeHa@BDgk_CJN(&a!H

literal 0
HcmV?d00001

diff --git a/llvm/test/Object/objdump-export-list.test b/llvm/test/Object/objdump-export-list.test
new file mode 100644
index 0000000..74344c1
--- /dev/null
+++ b/llvm/test/Object/objdump-export-list.test
@@ -0,0 +1,4 @@
+RUN: llvm-objdump -exports-trie %p/Inputs/macho-no-exports.dylib | FileCheck %s
+
+; Test that we don't crash with an empty export list.
+CHECK: macho-no-exports.dylib: file format Mach-O 64-bit x86-64
-- 
2.7.4