Fix a memory leak in MachOObjectFile.

MachOObjectFile owns a MachOObj, but never frees it. Both MachOObjectFile
and MachOObj want to own the MemoryBuffer, though, so we have to be careful
and give them each one of their own.

Thanks to Greg Clayton, Eric Christopher and Michael Spencer for helping
figure out what's going wrong here.

rdar://12561773

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168923 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Object/MachO.h

@@ -44,7 +44,7 @@ public:
   virtual unsigned getArch() const;
   virtual StringRef getLoadName() const;
 
-  MachOObject *getObject() { return MachOObj; }
+  MachOObject *getObject() { return MachOObj.get(); }
 
   static inline bool classof(const Binary *v) {
     return v->isMachO();
@@ -104,7 +104,7 @@ protected:
   virtual error_code getLibraryPath(DataRefImpl LibData, StringRef &Res) const;
 
 private:
-  MachOObject *MachOObj;
+  OwningPtr<MachOObject> MachOObj;
   mutable uint32_t RegisteredStringTable;
   typedef SmallVector<DataRefImpl, 1> SectionList;
   SectionList Sections;

lib/Object/MachOObjectFile.cpp

@@ -50,7 +50,14 @@ ObjectFile *ObjectFile::createMachOObjectFile(MemoryBuffer *Buffer) {
   MachOObject *MachOObj = MachOObject::LoadFromBuffer(Buffer, &Err);
   if (!MachOObj)
     return NULL;
-  return new MachOObjectFile(Buffer, MachOObj, ec);
+  // MachOObject takes ownership of the Buffer we passed to it, and
+  // MachOObjectFile does, too, so we need to make sure they don't get the
+  // same object. A MemoryBuffer is cheap (it's just a reference to memory,
+  // not a copy of the memory itself), so just make a new copy here for
+  // the MachOObjectFile.
+  MemoryBuffer *NewBuffer =
+    MemoryBuffer::getMemBuffer(Buffer->getBuffer(), "", false);
+  return new MachOObjectFile(NewBuffer, MachOObj, ec);
 }
 
 /*===-- Symbols -----------------------------------------------------------===*/
@@ -474,7 +481,7 @@ error_code MachOObjectFile::getSectionName(DataRefImpl DRI,
                                            StringRef &Result) const {
   // FIXME: thread safety.
   static char result[34];
-  if (is64BitLoadCommand(MachOObj, DRI)) {
+  if (is64BitLoadCommand(MachOObj.get(), DRI)) {
     InMemoryStruct<macho::Segment64LoadCommand> SLC;
     LoadCommandInfo LCI = MachOObj->getLoadCommandInfo(DRI.d.a);
     MachOObj->ReadSegment64LoadCommand(LCI, SLC);
@@ -501,7 +508,7 @@ error_code MachOObjectFile::getSectionName(DataRefImpl DRI,
 
 error_code MachOObjectFile::getSectionAddress(DataRefImpl DRI,
                                               uint64_t &Result) const {
-  if (is64BitLoadCommand(MachOObj, DRI)) {
+  if (is64BitLoadCommand(MachOObj.get(), DRI)) {
     InMemoryStruct<macho::Section64> Sect;
     getSection64(DRI, Sect);
     Result = Sect->Address;
@@ -515,7 +522,7 @@ error_code MachOObjectFile::getSectionAddress(DataRefImpl DRI,
 
 error_code MachOObjectFile::getSectionSize(DataRefImpl DRI,
                                            uint64_t &Result) const {
-  if (is64BitLoadCommand(MachOObj, DRI)) {
+  if (is64BitLoadCommand(MachOObj.get(), DRI)) {
     InMemoryStruct<macho::Section64> Sect;
     getSection64(DRI, Sect);
     Result = Sect->Size;
@@ -529,7 +536,7 @@ error_code MachOObjectFile::getSectionSize(DataRefImpl DRI,
 
 error_code MachOObjectFile::getSectionContents(DataRefImpl DRI,
                                                StringRef &Result) const {
-  if (is64BitLoadCommand(MachOObj, DRI)) {
+  if (is64BitLoadCommand(MachOObj.get(), DRI)) {
     InMemoryStruct<macho::Section64> Sect;
     getSection64(DRI, Sect);
     Result = MachOObj->getData(Sect->Offset, Sect->Size);
@@ -543,7 +550,7 @@ error_code MachOObjectFile::getSectionContents(DataRefImpl DRI,
 
 error_code MachOObjectFile::getSectionAlignment(DataRefImpl DRI,
                                                 uint64_t &Result) const {
-  if (is64BitLoadCommand(MachOObj, DRI)) {
+  if (is64BitLoadCommand(MachOObj.get(), DRI)) {
     InMemoryStruct<macho::Section64> Sect;
     getSection64(DRI, Sect);
     Result = uint64_t(1) << Sect->Align;
@@ -557,7 +564,7 @@ error_code MachOObjectFile::getSectionAlignment(DataRefImpl DRI,
 
 error_code MachOObjectFile::isSectionText(DataRefImpl DRI,
                                           bool &Result) const {
-  if (is64BitLoadCommand(MachOObj, DRI)) {
+  if (is64BitLoadCommand(MachOObj.get(), DRI)) {
     InMemoryStruct<macho::Section64> Sect;
     getSection64(DRI, Sect);
     Result = !strcmp(Sect->Name, "__text");
@@ -664,7 +671,7 @@ relocation_iterator MachOObjectFile::getSectionRelBegin(DataRefImpl Sec) const {
 }
 relocation_iterator MachOObjectFile::getSectionRelEnd(DataRefImpl Sec) const {
   uint32_t last_reloc;
-  if (is64BitLoadCommand(MachOObj, Sec)) {
+  if (is64BitLoadCommand(MachOObj.get(), Sec)) {
     InMemoryStruct<macho::Section64> Sect;
     getSection64(Sec, Sect);
     last_reloc = Sect->NumRelocationTableEntries;