[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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224563 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Object/MachOObjectFile.cpp b/lib/Object/MachOObjectFile.cpp
index fd086af6d527de44d7a17d3e1e8da336a434e420..92981fe6b7e91798b3cc76b31640a98cad620778 100644 (file)
--- a/lib/Object/MachOObjectFile.cpp
+++ b/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/test/Object/Inputs/macho-no-exports.dylib b/test/Object/Inputs/macho-no-exports.dylib
new file mode 100755 (executable)
index 0000000..6e1be6c
Binary files /dev/null and b/test/Object/Inputs/macho-no-exports.dylib differ

diff --git a/test/Object/objdump-export-list.test b/test/Object/objdump-export-list.test
new file mode 100644 (file)
index 0000000..74344c1
--- /dev/null
+++ b/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