[llvm-objdump] Fix memory leaks in macho dump

[fjricci]

Summary

Detected by LeakSanitizer for Darwin

[compnerd]

tools/llvm-objdump/MachODump.cpp

6050

Ugh, that is a confusing call. xar_extract_tobuffersz will allocate the buffer, so, yeah, the allocation there was unnecessary.

[fjricci]

Only delete buffer if xar_extract_tobuffersz succeeds

[dblaikie]

llvm/trunk/tools/llvm-objdump/MachODump.cpp

5884 ↗

(On Diff #115036)

Any chance of an RAII API for this resource, to avoid the accident-prone manual cleanup/free?

tools/llvm-objdump/MachODump.cpp

if(mtime != nullptr){
       outs() << " ";
       for( ; *m != 'Z' && *m != '\0'; m++)
         outs() << *m;
       outs() << " ";
     }
     if(name != nullptr)
       outs() << name;
     outs() << "\n";
+    xar_iter_free(xp);
   }
+  xar_iter_free(xi);
 }
 
 static void DumpBitcodeSection(MachOObjectFile *O, const char *sect,
                                 uint32_t size, bool verbose,
                                 bool PrintXarHeader, bool PrintXarFileHeaders,
                                 std::string XarMemberName) {
   if(size < sizeof(struct xar_header)) {
     outs() << "size of (__LLVM,__bundle) section too small (smaller than size "
#endif
      */
     if (member_name != NULL && member_type != NULL &&
         strcmp(member_type, "file") == 0 &&
         member_size_string != NULL){
       // Extract the file into a buffer.
       char *endptr;
       member_size = strtoul(member_size_string, &endptr, 10);
       if (*endptr == '\0' && member_size != 0) {
-        char *buffer = (char *)::operator new(member_size);
+        char *buffer;
         if (xar_extract_tobuffersz(xar, xf, &buffer, &member_size) == 0) {
 #if 0 // Useful for debugging.
     outs() << "xar member: " << member_name << " extracted\n";
 #endif
           // Set the XarMemberName we want to see printed in the header.
           std::string OldXarMemberName;
           // If XarMemberName is already set this is nested. So
           // save the old name and create the nested name.
           if (!XarMemberName.empty()) {
#endif
             if (sys::IsLittleEndianHost)
               swapStruct(XarHeader);
             if (XarHeader.magic == XAR_HEADER_MAGIC)
               DumpBitcodeSection(O, buffer, member_size, verbose,
                                  PrintXarHeader, PrintXarFileHeaders,
                                  XarMemberName);
           }
           XarMemberName = OldXarMemberName;
-        }
           delete buffer;
         }
       }
+    }
     xar_iter_free(xp);
   }
+  xar_iter_free(xi);
   xar_close(xar);
 }
 #endif // defined(HAVE_LIBXAR)
 
 static void printObjcMetaData(MachOObjectFile *O, bool verbose) {
   if (O->is64Bit())
     printObjc2_64bit_MetaData(O, verbose);
   else {