Index: lld/test/ELF/linkerscript/non-alloc-segment.s
===================================================================
--- lld/test/ELF/linkerscript/non-alloc-segment.s
+++ lld/test/ELF/linkerscript/non-alloc-segment.s
@@ -29,7 +29,7 @@
 # CHECK-NEXT:   00     .text
 # CHECK-NEXT:   01     .foo
 
-# PHDR: Type:  (0x12345678)
+# PHDR:      Type: Unknown (0x12345678)
 # PHDR-NEXT: Offset: 0x1004
 # PHDR-NEXT: VirtualAddress
 # PHDR-NEXT: PhysicalAddress
Index: lld/test/ELF/linkerscript/phdrs.s
===================================================================
--- lld/test/ELF/linkerscript/phdrs.s
+++ lld/test/ELF/linkerscript/phdrs.s
@@ -99,7 +99,7 @@
 
 # INT-PHDRS:      ProgramHeaders [
 # INT-PHDRS:        ProgramHeader {
-# INT-PHDRS:           Type:  (0x11223344)
+# INT-PHDRS:           Type: Unknown (0x11223344)
 # INT-PHDRS-NEXT:      Offset: 0xB0
 # INT-PHDRS-NEXT:      VirtualAddress: 0xB0
 # INT-PHDRS-NEXT:      PhysicalAddress: 0xB0
Index: llvm/test/tools/llvm-readobj/ELF/program-headers.test
===================================================================
--- llvm/test/tools/llvm-readobj/ELF/program-headers.test
+++ llvm/test/tools/llvm-readobj/ELF/program-headers.test
@@ -222,7 +222,7 @@
 # ELF-LLVM-NEXT:     Alignment: 1
 # ELF-LLVM-NEXT:   }
 # ELF-LLVM-NEXT:   ProgramHeader {
-# ELF-LLVM-NEXT:     Type:  (0x60000000)
+# ELF-LLVM-NEXT:     Type: Unknown (0x60000000)
 # ELF32-LLVM-NEXT:   Offset: 0x314
 # ELF64-LLVM-NEXT:   Offset: 0x548
 # ELF-LLVM-NEXT:     VirtualAddress: 0x1000
@@ -330,7 +330,7 @@
 # ELF-LLVM-NEXT:     Alignment: 1
 # ELF-LLVM-NEXT:   }
 # ELF-LLVM-NEXT:   ProgramHeader {
-# ELF-LLVM-NEXT:     Type:  (0x6FFFFFFF)
+# ELF-LLVM-NEXT:     Type: Unknown (0x6FFFFFFF)
 # ELF32-LLVM-NEXT:   Offset: 0x314
 # ELF64-LLVM-NEXT:   Offset: 0x548
 # ELF-LLVM-NEXT:     VirtualAddress: 0x1000
@@ -342,7 +342,7 @@
 # ELF-LLVM-NEXT:     Alignment: 1
 # ELF-LLVM-NEXT:   }
 # ELF-LLVM-NEXT:   ProgramHeader {
-# ELF-LLVM-NEXT:     Type:  (0x70000000)
+# ELF-LLVM-NEXT:     Type: Unknown (0x70000000)
 # ELF32-LLVM-NEXT:   Offset: 0x314
 # ELF64-LLVM-NEXT:   Offset: 0x548
 # ELF-LLVM-NEXT:     VirtualAddress: 0x1000
@@ -354,7 +354,7 @@
 # ELF-LLVM-NEXT:     Alignment: 1
 # ELF-LLVM-NEXT:   }
 # ELF-LLVM-NEXT:   ProgramHeader {
-# ELF-LLVM-NEXT:     Type:  (0x70000001)
+# ELF-LLVM-NEXT:     Type: Unknown (0x70000001)
 # ELF32-LLVM-NEXT:   Offset: 0x314
 # ELF64-LLVM-NEXT:   Offset: 0x548
 # ELF-LLVM-NEXT:     VirtualAddress: 0x1000
@@ -366,7 +366,7 @@
 # ELF-LLVM-NEXT:     Alignment: 1
 # ELF-LLVM-NEXT:   }
 # ELF-LLVM-NEXT:   ProgramHeader {
-# ELF-LLVM-NEXT:     Type:  (0x70000002)
+# ELF-LLVM-NEXT:     Type: Unknown (0x70000002)
 # ELF32-LLVM-NEXT:   Offset: 0x314
 # ELF64-LLVM-NEXT:   Offset: 0x548
 # ELF-LLVM-NEXT:     VirtualAddress: 0x1000
@@ -378,7 +378,7 @@
 # ELF-LLVM-NEXT:     Alignment: 1
 # ELF-LLVM-NEXT:   }
 # ELF-LLVM-NEXT:   ProgramHeader {
-# ELF-LLVM-NEXT:     Type:  (0x70000003)
+# ELF-LLVM-NEXT:     Type: Unknown (0x70000003)
 # ELF32-LLVM-NEXT:   Offset: 0x314
 # ELF64-LLVM-NEXT:   Offset: 0x548
 # ELF-LLVM-NEXT:     VirtualAddress: 0x1000
@@ -390,7 +390,7 @@
 # ELF-LLVM-NEXT:     Alignment: 1
 # ELF-LLVM-NEXT:   }
 # ELF-LLVM-NEXT:   ProgramHeader {
-# ELF-LLVM-NEXT:     Type:  (0x7FFFFFFF)
+# ELF-LLVM-NEXT:     Type: Unknown (0x7FFFFFFF)
 # ELF32-LLVM-NEXT:   Offset: 0x314
 # ELF64-LLVM-NEXT:   Offset: 0x548
 # ELF-LLVM-NEXT:     VirtualAddress: 0x1000
@@ -596,11 +596,11 @@
 # ARM-GNU-NEXT: <unknown>: 0x70000002 0x000548 0x0000000000001000 0x0000000000001000 0x000003 0x000003 0x1
 
 # ARM-LLVM:      ProgramHeader {
-# ARM-LLVM:        Type:  (0x70000000)
+# ARM-LLVM:        Type: Unknown (0x70000000)
 # ARM-LLVM:      ProgramHeader {
 # ARM-LLVM-NEXT:   Type: PT_ARM_EXIDX (0x70000001)
 # ARM-LLVM:      ProgramHeader {
-# ARM-LLVM-NEXT:   Type:  (0x70000002)
+# ARM-LLVM-NEXT:   Type: Unknown (0x70000002)
 
 ## Check how we dump MIPS specific program headers.
 # RUN: yaml2obj --docnum=1 -DBITS=64 -DMACHINE=EM_MIPS %s -o %tmips.elf
Index: llvm/tools/llvm-readobj/ELFDumper.cpp
===================================================================
--- llvm/tools/llvm-readobj/ELFDumper.cpp
+++ llvm/tools/llvm-readobj/ELFDumper.cpp
@@ -6516,9 +6516,10 @@
 
   for (const Elf_Phdr &Phdr : *PhdrsOrErr) {
     DictScope P(W, "ProgramHeader");
-    W.printHex("Type",
-               segmentTypeToString(Obj->getHeader()->e_machine, Phdr.p_type),
-               Phdr.p_type);
+    StringRef Type =
+        segmentTypeToString(Obj->getHeader()->e_machine, Phdr.p_type);
+
+    W.printHex("Type", Type.empty() ? "Unknown" : Type, Phdr.p_type);
     W.printHex("Offset", Phdr.p_offset);
     W.printHex("VirtualAddress", Phdr.p_vaddr);
     W.printHex("PhysicalAddress", Phdr.p_paddr);