diff --git a/lib/Object/MachOObjectFile.cpp b/lib/Object/MachOObjectFile.cpp
index fd3cb5efcfb..fcd7099954a 100644
--- a/lib/Object/MachOObjectFile.cpp
+++ b/lib/Object/MachOObjectFile.cpp
@@ -751,6 +751,7 @@ MachOObjectFile::MachOObjectFile(MemoryBufferRef Object, bool IsLittleEndian,
   const char *CodeSignDrsLoadCmd = nullptr;
   const char *VersLoadCmd = nullptr;
   const char *SourceLoadCmd = nullptr;
+  const char *EntryPointLoadCmd = nullptr;
   for (unsigned I = 0; I < LoadCommandCount; ++I) {
     if (is64Bit()) {
       if (Load.C.cmdsize % 8 != 0) {
@@ -891,6 +892,17 @@ MachOObjectFile::MachOObjectFile(MemoryBufferRef Object, bool IsLittleEndian,
         return;
       }
       SourceLoadCmd = Load.Ptr;
+    } else if (Load.C.cmd == MachO::LC_MAIN) {
+      if (Load.C.cmdsize != sizeof(MachO::entry_point_command)) {
+        Err = malformedError("LC_MAIN command " + Twine(I) +
+                             " has incorrect cmdsize");
+        return;
+      }
+      if (EntryPointLoadCmd) {
+        Err = malformedError("more than one LC_MAIN command");
+        return;
+      }
+      EntryPointLoadCmd = Load.Ptr;
     }
     if (I < LoadCommandCount - 1) {
       if (auto LoadOrErr = getNextLoadCommandInfo(this, I, Load))
diff --git a/test/Object/Inputs/macho-invalid-entry-bad-size b/test/Object/Inputs/macho-invalid-entry-bad-size
new file mode 100644
index 00000000000..b7944be6be8
Binary files /dev/null and b/test/Object/Inputs/macho-invalid-entry-bad-size differ
diff --git a/test/Object/Inputs/macho-invalid-entry-more-than-one b/test/Object/Inputs/macho-invalid-entry-more-than-one
new file mode 100644
index 00000000000..de08dd5a830
Binary files /dev/null and b/test/Object/Inputs/macho-invalid-entry-more-than-one differ
diff --git a/test/Object/macho-invalid.test b/test/Object/macho-invalid.test
index c7d7b05d5da..9c902aff814 100644
--- a/test/Object/macho-invalid.test
+++ b/test/Object/macho-invalid.test
@@ -328,3 +328,9 @@ INVALID-SOURCE-BAD-SIZE: macho-invalid-source-bad-size': truncated or malformed
 
 RUN: not llvm-objdump -macho -private-headers %p/Inputs/macho-invalid-source-more-than-one 2>&1 | FileCheck -check-prefix INVALID-SOURCE-MORE-THAN-ONE %s
 INVALID-SOURCE-MORE-THAN-ONE: macho-invalid-source-more-than-one': truncated or malformed object (more than one LC_SOURCE_VERSION command)
+
+RUN: not llvm-objdump -macho -private-headers %p/Inputs/macho-invalid-entry-bad-size 2>&1 | FileCheck -check-prefix INVALID-ENTRY-BAD-SIZE %s
+INVALID-ENTRY-BAD-SIZE: macho-invalid-entry-bad-size': truncated or malformed object (LC_MAIN command 0 has incorrect cmdsize)
+
+RUN: not llvm-objdump -macho -private-headers %p/Inputs/macho-invalid-entry-more-than-one 2>&1 | FileCheck -check-prefix INVALID-ENTRY-MORE-THAN-ONE %s
+INVALID-ENTRY-MORE-THAN-ONE: macho-invalid-entry-more-than-one': truncated or malformed object (more than one LC_MAIN command)