[llvm] r225271 - Don't loop endlessly for MachO files with 0 ncmds

[Filipe Cabecinhas]

Author: filcab
Date: Tue Jan  6 11:08:26 2015
New Revision: 225271

URL: http://llvm.org/viewvc/llvm-project?rev=225271&view=rev
Log:
Don't loop endlessly for MachO files with 0 ncmds

Added:
    llvm/trunk/test/Object/Inputs/macho-zero-ncmds
    llvm/trunk/test/Object/objdump-macho-quirks.test
Modified:
    llvm/trunk/lib/Object/MachOObjectFile.cpp
    llvm/trunk/tools/llvm-objdump/MachODump.cpp

Modified: llvm/trunk/lib/Object/MachOObjectFile.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Object/MachOObjectFile.cpp?rev=225271&r1=225270&r2=225271&view=diff
==============================================================================
--- llvm/trunk/lib/Object/MachOObjectFile.cpp (original)
+++ llvm/trunk/lib/Object/MachOObjectFile.cpp Tue Jan  6 11:08:26 2015
@@ -236,6 +236,9 @@ MachOObjectFile::MachOObjectFile(MemoryB
       DataInCodeLoadCmd(nullptr), DyldInfoLoadCmd(nullptr),
       UuidLoadCmd(nullptr), HasPageZeroSegment(false) {
   uint32_t LoadCommandCount = this->getHeader().ncmds;
+  if (LoadCommandCount == 0)
+    return;
+
   MachO::LoadCommandType SegmentLoadType = is64Bit() ?
     MachO::LC_SEGMENT_64 : MachO::LC_SEGMENT;
 

Added: llvm/trunk/test/Object/Inputs/macho-zero-ncmds
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Object/Inputs/macho-zero-ncmds?rev=225271&view=auto
==============================================================================
Binary files llvm/trunk/test/Object/Inputs/macho-zero-ncmds (added) and llvm/trunk/test/Object/Inputs/macho-zero-ncmds Tue Jan  6 11:08:26 2015 differ

Added: llvm/trunk/test/Object/objdump-macho-quirks.test
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Object/objdump-macho-quirks.test?rev=225271&view=auto
==============================================================================
--- llvm/trunk/test/Object/objdump-macho-quirks.test (added)
+++ llvm/trunk/test/Object/objdump-macho-quirks.test Tue Jan  6 11:08:26 2015
@@ -0,0 +1,9 @@
+RUN: llvm-objdump -private-headers %p/Inputs/macho-zero-ncmds \
+RUN:         | FileCheck %s -check-prefix A
+
+// Check that we don't get an infinite loop if ncmds = 0
+A: file format Mach-O 64-bit unknown
+A: Mach header
+A:      magic cputype cpusubtype  caps    filetype ncmds sizeofcmds      flags
+A: MH_MAGIC_64  0x00      OBJECT     0          0 0x00000000
+

Modified: llvm/trunk/tools/llvm-objdump/MachODump.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-objdump/MachODump.cpp?rev=225271&r1=225270&r2=225271&view=diff
==============================================================================
--- llvm/trunk/tools/llvm-objdump/MachODump.cpp (original)
+++ llvm/trunk/tools/llvm-objdump/MachODump.cpp Tue Jan  6 11:08:26 2015
@@ -4204,6 +4204,8 @@ static void PrintLinkEditDataCommand(Mac
 static void PrintLoadCommands(const MachOObjectFile *Obj, uint32_t ncmds,
                               uint32_t filetype, uint32_t cputype,
                               bool verbose) {
+  if (ncmds == 0)
+    return;
   StringRef Buf = Obj->getData();
   MachOObjectFile::LoadCommandInfo Command = Obj->getFirstLoadCommandInfo();
   for (unsigned i = 0;; ++i) {