[llvm-readobj] Add support for decoding FreeBSD ELF notes

[arichardson]

Summary

The current support only printed coredump notes, but most binaries also
contain notes. This change adds names for four FreeBSD-specific notes and
pretty-prints three of them:

NT_FREEBSD_ABI_TAG:
This note holds a 32-bit (decimal) integer containing the value of the
__FreeBSD_version macro, which is defined in crt1.o and will hold a value
such as 1300076 for a binary build on a FreeBSD 13 system.

NT_FREEBSD_ARCH_TAG:
A string containing the value of the build-time MACHINE_ARCH

NT_FREEBSD_FEATURE_CTL: A 32-bit flag that indicates to the kernel that
the binary wants certain bevahiour. Examples include setting
NT_FREEBSD_FCTL_ASLR_DISABLE which tells the kernel to disable ASLR.

After this change llvm-readobj also no longer decodes coredump-only
FreeBSD notes in non-coredump files. I've also converted the
note-freebsd.s test to use yaml2obj instead of llvm-mc.

[jhenderson]

llvm/test/tools/llvm-readobj/ELF/note-freebsd-core.test

1

binaries -> coredump(?)

2

Minor point, but we've started to tend to use -o %t.o instead of shell redirection in newer tests.

3–4

Two spurious lines?

10–13

Could you remove the excessive whitespace, please? I find it makes things more readable. I'd prefer it if all values line up, with the minimal amount of space possible, i.e. something like:

Class:   ELFCLASS64
Data:    ELFDATA2LSB
Type:    ET_CORE
Machine: EM_RISCV

19

Desc is optional - it emits an empty description if unspecified, so you can delete this line (and similar ones below).

20

Could you make a small change to yaml2obj to allow it to take the NT_* string as well as hex numbers, if it's practical? We already do that for most other enum-style fields (e.g. dynamic entries, section types etc), so it should be straightforward enough to copy what has been done before.

34

Is this just arbitrary data? If so, can you make it look more arbitrary by reducing the size and maybe make it some sort of pattern like "aabbccdd00"? If not, please add a comment showing what this should represent.

35

Is Type 3 one of the non-core ones, or just undefined? Please add a comment explaining why "3".

llvm/test/tools/llvm-readobj/ELF/note-freebsd.test

1

binaries -> binary

2

Same comment re. -o, whitespace in the YAML, using enum strings etc also apply in this test.

3

Spurious line?

16–17

You should be able to delete the flag and address values here. They aren't relevant to the test.

20

I think there should be a test case for a core note in this file, showing the behaviour for this case.

33

Delete extra blank line.

llvm/tools/llvm-readobj/ELFDumper.cpp

4874

Seems like we only test a small number of these, but we should test all of them. Could you extend the test accordingly (possibly as a separate change), please?

4887

Ditto - this seems to be untested.

5165

Nit: missing trailing full stop.

5171

I don't see any testing for this and the other corrupt tag code path?

5186–5188

A non-zero Feature flags test would be nice.

6542

Nit: missing trailing full stops for all these comments.

[arichardson]

Thanks for the detailed review! I'll update this patch early next week.
Many of the problems exist because I simply converted the existing assembly test to a YAML one instead of writing a new one.

[emaste]

@arichardson do you think you'll get back to this?

[arichardson]

In D74393#2535382, @emaste wrote:

@arichardson do you think you'll get back to this?

I'll try and update it this afternoon.

[arichardson]

Address review comments and rebase on latest HEAD

[arichardson]

llvm/test/tools/llvm-readobj/ELF/note-freebsd-core.test

34

Yes that makes sense, I just copied the value from the .s file.

35

Again this is a copy from the .s file, and it is a valid type.

[emaste]

llvm/test/tools/llvm-readobj/ELF/note-freebsd.test

95

0xfffffff0 looks like an ELF Tool Chain bug :(

llvm/tools/llvm-readobj/ELFDumper.cpp

6627–6628

yes, should fall back to raw data if no pretty printer available; GNU and ELF Tool Chain readelf do this

[emaste]

llvm/test/tools/llvm-readobj/ELF/note-freebsd.test

95

Oh, nvm you set the field to 0xFFFFFFFF. ELF Tool Chain masks off the known bits as it prints them, and displays what's left.

[rupprecht]

llvm/tools/llvm-readobj/ELFDumper.cpp

5162–5167

Can you define this as an enum, like in llvm/include/llvm/BinaryFormat/ELF.h?

[arichardson]

llvm/tools/llvm-readobj/ELFDumper.cpp

5162–5167

Sounds good, I'll also move it to llvm/include/llvm/BinaryFormat/ELF.h

[jhenderson]

llvm/include/llvm/BinaryFormat/ELF.h

1521

Nit: add trailing full stop (same below for core note types comment).

1528

Nit: I think adding a blank line before this would better match existing style.

llvm/test/tools/llvm-readobj/ELF/note-freebsd-core.test

44

Nit: delete extra ProgramHeaders:

74

Why the <?> for the name? Sounds like something odd is going on if I follow it correctly (there are perfectly good section headers as far as I can see from yaml). If it's expected, add a comment explaining why.

llvm/tools/llvm-readobj/ELFDumper.cpp

5319–5323

I might have missed it, but is there testing for both halves of this code path (i.e. regular core notes + FreeBSD)?

[arichardson]

address comments and rebase on top of D74367

[arichardson]

llvm/test/tools/llvm-readobj/ELF/note-freebsd-core.test

74

I don't understand why this is happening, but it also appears to affect other tests. Possibly a bug in yaml2obj? Unfortunately I don't have time to investigate this.

llvm/test/tools/llvm-readobj/ELF/note-freebsd.test

95

Yeah I'm not sure what the best output format is. I think just printing the raw value in parens seems less confusing than printing the non-matching bits.

llvm/tools/llvm-readobj/ELFDumper.cpp

5319–5323

note-freebsd-core.test checks for NT_PRPSINFO (which is one of the generic core notes) with a FreeBSD owner.

[jhenderson]

LGTM, once the other related patches land. The <?> oddity can be sorted separately (unless a warning makes it obvious we're doing something silly in the YAML). I'm happy to investigate it myself, if you could provide the stderr (if any)?

llvm/test/tools/llvm-readobj/ELF/note-freebsd-core.test

74

Is there anything on stderr? I'd expect a warning in this case.

[arichardson]

llvm/test/tools/llvm-readobj/ELF/note-freebsd-core.test

74

No stderr, but it appears that the name is printed if I change it from ET_CORE to ET_DYN.

[jhenderson]

llvm/test/tools/llvm-readobj/ELF/note-freebsd-core.test

74

Ah, that makes sense. See the StartNotes lambda in the LLVM style printing of the notes data. It seems like we always print Section: for LLVM, even when there's no section name to be had. I haven't looked, but I suspect section names are ignored in ET_CORE files, since they aren't really expected to have sections. I've filed https://bugs.llvm.org/show_bug.cgi?id=49088 to suggest not to print the Section: line in such situations.

llvm/include/llvm/BinaryFormat/ELF.h

enum {
   VERSYM_HIDDEN = 0x8000   // Hidden bit (non-default version)
 };
 
 // ElfXX_VerNeed structure version (GNU versioning)
 enum { VER_NEED_NONE = 0, VER_NEED_CURRENT = 1 };
 
 // SHT_NOTE section types
 enum {
+  NT_FREEBSD_ABI_TAG = 1,
+  NT_FREEBSD_NOINIT_TAG = 2,
+  NT_FREEBSD_ARCH_TAG = 3,
+  NT_FREEBSD_FEATURE_CTL = 4,
   NT_FREEBSD_THRMISC = 7,
   NT_FREEBSD_PROCSTAT_PROC = 8,
   NT_FREEBSD_PROCSTAT_FILES = 9,
   NT_FREEBSD_PROCSTAT_VMMAP = 10,
   NT_FREEBSD_PROCSTAT_GROUPS = 11,
   NT_FREEBSD_PROCSTAT_UMASK = 12,
   NT_FREEBSD_PROCSTAT_RLIMIT = 13,
   NT_FREEBSD_PROCSTAT_OSREL = 14,
enum : unsigned {
   GNU_PROPERTY_X86_FEATURE_2_YMM = 1 << 4,
   GNU_PROPERTY_X86_FEATURE_2_ZMM = 1 << 5,
   GNU_PROPERTY_X86_FEATURE_2_FXSR = 1 << 6,
   GNU_PROPERTY_X86_FEATURE_2_XSAVE = 1 << 7,
   GNU_PROPERTY_X86_FEATURE_2_XSAVEOPT = 1 << 8,
   GNU_PROPERTY_X86_FEATURE_2_XSAVEC = 1 << 9,
 };
 
 // AMDGPU-specific section indices.
 enum {
   SHN_AMDGPU_LDS = 0xff00, // Variable in LDS; symbol encoded like SHN_COMMON
 };
 
 // AMD specific notes. (Code Object V2)
 enum {
   // Note types with values between 0 and 9 (inclusive) are reserved.
   NT_AMD_AMDGPU_HSA_METADATA = 10,
   NT_AMD_AMDGPU_ISA = 11,
   NT_AMD_AMDGPU_PAL_METADATA = 12
 };
 
 // AMDGPU specific notes. (Code Object V3)
 enum {
   // Note types with values between 0 and 31 (inclusive) are reserved.

llvm/test/tools/llvm-readobj/ELF/note-freebsd-core.test

+## Test that note values are interpreted correctly for FreeBSD binaries files.
+# RUN: yaml2obj %s > %t.o
+# RUN: llvm-readelf --notes %t.o
+# RUN: llvm-readobj --notes %t.o
+# RUN: llvm-readelf --notes %t.o | FileCheck %s --check-prefix=GNU --strict-whitespace
+# RUN: llvm-readobj --notes %t.o | FileCheck %s --check-prefix=LLVM --strict-whitespace
+
+--- !ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_CORE
+  Machine:         EM_RISCV
+Sections:
+  - Name:            .note.foo
+    Type:            SHT_NOTE
+    Notes:
+      - Name:            FreeBSD
+        Desc:            ''
+        Type:            0x00000007 # NT_FREEBSD_THRMISC
+      - Name:            FreeBSD
+        Desc:            ''
+        Type:            0x00000008 # NT_FREEBSD_PROC
+  - Name:            .note.bar
+    Type:            SHT_NOTE
+    Notes:
+      - Name:            FreeBSD
+        Desc:            ''
+        Type:            0x00000009 # NT_FREEBSD_FILES
+  - Name:            .note.baz
+    Type:            SHT_NOTE
+    Notes:
+      - Name:            FreeBSD
+        Desc:            '4c6f72656d20697073756d20646f6c6f722073697420616d65740a00'
+        Type:            0x00000003
+ProgramHeaders:
+  - Type:        PT_NOTE
+    Sections:
+      - Section: .note.foo
+  - Type:        PT_NOTE
+    Sections:
+      - Section: .note.bar
+  - Type:        PT_NOTE
+    Sections:
+      - Section: .note.baz
+
+# GNU:      Displaying notes found at file offset
+# GNU-NEXT:   Owner                Data size  Description
+# GNU-NEXT:   FreeBSD              0x00000000 NT_THRMISC (thrmisc structure)
+# GNU-NEXT:   FreeBSD              0x00000000 NT_PROCSTAT_PROC (proc data)
+# GNU-NEXT: Displaying notes found at file offset
+# GNU-NEXT:   Owner                Data size  Description
+# GNU-NEXT:   FreeBSD              0x00000000 NT_PROCSTAT_FILES (files data)
+# GNU-NEXT: Displaying notes found at file offset
+# GNU-NEXT:   Owner                Data size  Description
+# GNU-NEXT:   FreeBSD              0x0000001c Unknown note type: (0x00000003)
+# GNU-NEXT:     Description data: 4c 6f 72 65 6d 20 69 70 73 75 6d 20 64 6f 6c 6f 72 20 73 69 74 20 61 6d 65 74 0a 00
+# GNU-EMPTY:
+
+# LLVM:      Notes [
+# LLVM-NEXT:   NoteSection {
+# LLVM-NEXT:     Offset:
+# LLVM-NEXT:     Size:
+# LLVM-NEXT:     Note {
+# LLVM-NEXT:       Owner: FreeBSD
+# LLVM-NEXT:       Data size: 0x0
+# LLVM-NEXT:       Type: NT_THRMISC (thrmisc structure)
+# LLVM-NEXT:     }
+# LLVM-NEXT:     Note {
+# LLVM-NEXT:       Owner: FreeBSD
+# LLVM-NEXT:       Data size: 0x0
+# LLVM-NEXT:       Type: NT_PROCSTAT_PROC (proc data)
+# LLVM-NEXT:     }
+# LLVM-NEXT:   }
+# LLVM-NEXT:   NoteSection {
+# LLVM-NEXT:     Offset: 0x110
+# LLVM-NEXT:     Size: 0x14
+# LLVM-NEXT:     Note {
+# LLVM-NEXT:       Owner: FreeBSD
+# LLVM-NEXT:       Data size: 0x0
+# LLVM-NEXT:       Type: NT_PROCSTAT_FILES (files data)
+# LLVM-NEXT:     }
+# LLVM-NEXT:   }
+# LLVM-NEXT:   NoteSection {
+# LLVM-NEXT:     Offset: 0x124
+# LLVM-NEXT:     Size: 0x30
+# LLVM-NEXT:     Note {
+# LLVM-NEXT:       Owner: FreeBSD
+# LLVM-NEXT:       Data size: 0x1C
+# LLVM-NEXT:       Type: Unknown note type: (0x00000003)
+# LLVM-NEXT:       Description data (
+# LLVM-NEXT:         0000: 4C6F7265 6D206970 73756D20 646F6C6F  |Lorem ipsum dolo|
+# LLVM-NEXT:         0010: 72207369 7420616D 65740A00           |r sit amet..|
+# LLVM-NEXT:       )
+# LLVM-NEXT:     }
+# LLVM-NEXT:   }
+# LLVM-NEXT: ]

llvm/test/tools/llvm-readobj/ELF/note-freebsd.s

-// REQUIRES: x86-registered-target
-// RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o %t.o
-
-// RUN: llvm-readobj --notes %t.o | FileCheck %s --check-prefix=LLVM
-// RUN: llvm-readelf --notes %t.o | FileCheck %s --check-prefix=GNU
-
-// GNU:      Displaying notes found
-// GNU-NEXT:   Owner                Data size        Description
-// GNU-NEXT:   FreeBSD              0x00000000       NT_THRMISC (thrmisc structure)
-// GNU-NEXT:   FreeBSD              0x00000000       NT_PROCSTAT_PROC (proc data)
-// GNU-NEXT: Displaying notes found
-// GNU-NEXT:   Owner                Data size        Description
-// GNU-NEXT:   FreeBSD              0x00000000       NT_PROCSTAT_FILES (files data)
-// GNU-NEXT: Displaying notes found
-// GNU-NEXT:   Owner                Data size        Description
-// GNU-NEXT:   FreeBSD              0x0000001c       Unknown note type: (0x00000003)
-// GNU-NEXT:     Description data: 4c 6f 72 65 6d 20 69 70 73 75 6d 20 64 6f 6c 6f 72 20 73 69 74 20 61 6d 65 74 00 00
-
-// LLVM:      Notes [
-// LLVM-NEXT:   NoteSection {
-// LLVM-NEXT:     Offset:
-// LLVM-NEXT:     Size:
-// LLVM-NEXT:     Note {
-// LLVM-NEXT:       Owner: FreeBSD
-// LLVM-NEXT:       Data size: 0x0
-// LLVM-NEXT:       Type: NT_THRMISC (thrmisc structure)
-// LLVM-NEXT:     }
-// LLVM-NEXT:     Note {
-// LLVM-NEXT:       Owner: FreeBSD
-// LLVM-NEXT:       Data size: 0x0
-// LLVM-NEXT:       Type: NT_PROCSTAT_PROC (proc data)
-// LLVM-NEXT:     }
-// LLVM-NEXT:   }
-// LLVM-NEXT:   NoteSection {
-// LLVM-NEXT:     Offset: 0x68
-// LLVM-NEXT:     Size: 0x14
-// LLVM-NEXT:     Note {
-// LLVM-NEXT:       Owner: FreeBSD
-// LLVM-NEXT:       Data size: 0x0
-// LLVM-NEXT:       Type: NT_PROCSTAT_FILES (files data)
-// LLVM-NEXT:     }
-// LLVM-NEXT:   }
-// LLVM-NEXT:   NoteSection {
-// LLVM-NEXT:     Offset: 0x7C
-// LLVM-NEXT:     Size: 0x30
-// LLVM-NEXT:     Note {
-// LLVM-NEXT:       Owner: FreeBSD
-// LLVM-NEXT:       Data size: 0x1C
-// LLVM-NEXT:       Type: Unknown note type: (0x00000003)
-// LLVM-NEXT:       Description data (
-// LLVM-NEXT:         0000: 4C6F7265 6D206970 73756D20 646F6C6F  |Lorem ipsum dolo|
-// LLVM-NEXT:         0010: 72207369 7420616D 65740000           |r sit amet..|
-// LLVM-NEXT:       )
-// LLVM-NEXT:     }
-// LLVM-NEXT:   }
-// LLVM-NEXT: ]
-
-.section ".note.foo", "a"
-  .align 4
-  .long 8 /* namesz */
-  .long 0 /* descsz */
-  .long 7 /* type = NT_FREEBSD_THRMISC */
-  .asciz "FreeBSD"
-  .long 8 /* namesz */
-  .long 0 /* descsz */
-  .long 8 /* type = NT_FREEBSD_PROC */
-  .asciz "FreeBSD"
-.section ".note.bar", "a"
-  .align 4
-  .long 8 /* namesz */
-  .long 0 /* descsz */
-  .long 9 /* type = NT_FREEBSD_FILES */
-  .asciz "FreeBSD"
-.section ".note.baz", "a"
-       .align 4
-       .long 8 /* namesz */
-       .long end - begin /* descsz */
-       .long 3 /* type */
-       .asciz "FreeBSD"
-begin:
-       .asciz "Lorem ipsum dolor sit amet"
-       .align 4
-end:

llvm/test/tools/llvm-readobj/ELF/note-freebsd.test

+## Test that note values are interpreted correctly for FreeBSD binaries files.
+# RUN: yaml2obj %s > %t.o
+# RUN: llvm-readobj --notes %t.o
+# RUN: llvm-readelf --notes %t.o | FileCheck %s --check-prefix=GNU --strict-whitespace
+# RUN: llvm-readobj --notes %t.o | FileCheck %s --check-prefix=LLVM --strict-whitespace
+
+--- !ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_EXEC
+  Machine:         EM_RISCV
+Sections:
+  - Name:            .note.tag
+    Type:            SHT_NOTE
+    Flags:           [ SHF_ALLOC ]
+    Address:         0x0000000000010270
+    AddressAlign:    0x0000000000000004
+    Notes:
+      - Name:            FreeBSD
+        Desc:            6CD61300
+        Type:            0x00000001
+      - Name:            FreeBSD
+        Desc:            '00000000'
+        Type:            0x00000004
+      - Name:            FreeBSD
+        Desc:            '00000000'
+        Type:            0x00000002
+      - Name:            FreeBSD
+        Desc:            '616263646566'
+        Type:            0xabcdef
+
+
+# GNU:     Displaying notes found at file offset 0x00000040 with length 0x00000064:
+# GNU-NEXT:  Owner                Data size   Description
+# GNU-NEXT:  FreeBSD              0x00000004  NT_FREEBSD_ABI_TAG (ABI version tag)
+# GNU-NEXT:    ABI: 1300076
+# GNU-NEXT:  FreeBSD              0x00000004  NT_FREEBSD_FEATURE_CTL (FreeBSD feature control)
+# GNU-NEXT:    Feature flags: 0x0
+# GNU-NEXT:  FreeBSD              0x00000004  NT_FREEBSD_NOINIT_TAG (no .init tag)
+# GNU-NEXT:    Description data: 00 00 00 00
+# GNU-NEXT:  FreeBSD              0x00000006  Unknown note type: (0x00abcdef)
+# GNU-NEXT:    Description data: 61 62 63 64 65 66
+# GNU-EMPTY:
+
+# LLVM:     Notes [
+# LLVM-NEXT:  NoteSection {
+# LLVM-NEXT:    Offset: 0x40
+# LLVM-NEXT:    Size: 0x64
+# LLVM-NEXT:    Note {
+# LLVM-NEXT:      Owner: FreeBSD
+# LLVM-NEXT:      Data size: 0x4
+# LLVM-NEXT:      Type: NT_FREEBSD_ABI_TAG (ABI version tag)
+# LLVM-NEXT:      ABI: 1300076
+# LLVM-NEXT:    }
+# LLVM-NEXT:    Note {
+# LLVM-NEXT:      Owner: FreeBSD
+# LLVM-NEXT:      Data size: 0x4
+# LLVM-NEXT:      Type: NT_FREEBSD_FEATURE_CTL (FreeBSD feature control)
+# LLVM-NEXT:      Flags: 0x0
+# LLVM-NEXT:      Description data (
+# LLVM-NEXT:        0000: 00000000                             |....|
+# LLVM-NEXT:      )
+# LLVM-NEXT:    }
+# LLVM-NEXT:    Note {
+# LLVM-NEXT:      Owner: FreeBSD
+# LLVM-NEXT:      Data size: 0x4
+# LLVM-NEXT:      Type: NT_FREEBSD_NOINIT_TAG (no .init tag)
+# LLVM-NEXT:      Description data (
+# LLVM-NEXT:        0000: 00000000                             |....|
+# LLVM-NEXT:      )
+# LLVM-NEXT:    }
+# LLVM-NEXT:    Note {
+# LLVM-NEXT:      Owner: FreeBSD
+# LLVM-NEXT:      Data size: 0x6
+# LLVM-NEXT:      Type: Unknown note type: (0x00abcdef)
+# LLVM-NEXT:      Description data (
+# LLVM-NEXT:        0000: 61626364 6566                        |abcdef|
+# LLVM-NEXT:      )
+# LLVM-NEXT:    }
+# LLVM-NEXT:  }
+# LLVM-NEXT:]

llvm/tools/llvm-readobj/ELFDumper.cpp

if (Note.ID == NT)
       return std::string(Note.Name);
 
   std::string string;
   raw_string_ostream OS(string);
   OS << format("Unknown note type: (0x%08x)", NT);
   return OS.str();
 }
 
-static std::string getFreeBSDNoteTypeName(const uint32_t NT) {
+static std::string getFreeBSDNoteTypeName(const uint32_t NT, bool IsCore) {
   static const struct {
     uint32_t ID;
     const char *Name;
-  } Notes[] = {
+  } CoreDumpNotes[] =
+      {
           {ELF::NT_FREEBSD_THRMISC, "NT_THRMISC (thrmisc structure)"},
           {ELF::NT_FREEBSD_PROCSTAT_PROC, "NT_PROCSTAT_PROC (proc data)"},
           {ELF::NT_FREEBSD_PROCSTAT_FILES, "NT_PROCSTAT_FILES (files data)"},
           {ELF::NT_FREEBSD_PROCSTAT_VMMAP, "NT_PROCSTAT_VMMAP (vmmap data)"},
           {ELF::NT_FREEBSD_PROCSTAT_GROUPS, "NT_PROCSTAT_GROUPS (groups data)"},
           {ELF::NT_FREEBSD_PROCSTAT_UMASK, "NT_PROCSTAT_UMASK (umask data)"},
           {ELF::NT_FREEBSD_PROCSTAT_RLIMIT, "NT_PROCSTAT_RLIMIT (rlimit data)"},
-      {ELF::NT_FREEBSD_PROCSTAT_OSREL, "NT_PROCSTAT_OSREL (osreldate data)"},
+          {ELF::NT_FREEBSD_PROCSTAT_OSREL,
+           "NT_PROCSTAT_OSREL (osreldate data)"},
           {ELF::NT_FREEBSD_PROCSTAT_PSSTRINGS,
            "NT_PROCSTAT_PSSTRINGS (ps_strings data)"},
           {ELF::NT_FREEBSD_PROCSTAT_AUXV, "NT_PROCSTAT_AUXV (auxv data)"},
+      },
+    OtherNotes[] = {
+        {ELF::NT_FREEBSD_ABI_TAG, "NT_FREEBSD_ABI_TAG (ABI version tag)"},
+        {ELF::NT_FREEBSD_NOINIT_TAG, "NT_FREEBSD_NOINIT_TAG (no .init tag)"},
+        {ELF::NT_FREEBSD_ARCH_TAG, "NT_FREEBSD_ARCH_TAG (architecture tag)"},
+        {ELF::NT_FREEBSD_FEATURE_CTL,
+         "NT_FREEBSD_FEATURE_CTL (FreeBSD feature control)"},
     };
-
+  const auto Notes =
+      IsCore ? makeArrayRef(CoreDumpNotes) : makeArrayRef(OtherNotes);
   for (const auto &Note : Notes)
     if (Note.ID == NT)
       return std::string(Note.Name);
 
   std::string string;
   raw_string_ostream OS(string);
   OS << format("Unknown note type: (0x%08x)", NT);
   return OS.str();
case ELF::NT_GNU_PROPERTY_TYPE_0:
     for (const auto &Property : getGNUPropertyList<ELFT>(Desc))
       OS << "    " << Property << "\n";
     break;
   }
   OS << '\n';
   return true;
 }
 
+template <typename ELFT>
+static bool printFreeBSDNote(raw_ostream &OS, uint32_t NoteType,
+                             ArrayRef<uint8_t> Desc, bool IsCore) {
+  if (IsCore)
+    return false; // No pretty-printing yet
+  switch (NoteType) {
+  default:
+    return false;
+  case ELF::NT_FREEBSD_ABI_TAG:
+    if (Desc.size() != 4) {
+      OS << "    <corrupt FREEBSD_ABI_TAG>\n";
+      return false;
+    }
+    OS << "    ABI: "
+       << support::endian::read32<ELFT::TargetEndianness>(Desc.data());
+    break;
+  case ELF::NT_FREEBSD_FEATURE_CTL:
+    if (Desc.size() != 4) {
+      OS << "    <corrupt FREEBSD_FEATURE_CTL>\n";
+      return false;
+    }
+    // TODO: decode flags
+    // #define  NT_FREEBSD_FCTL_ASLR_DISABLE  0x00000001
+    // #define  NT_FREEBSD_FCTL_PROTMAX_DISABLE 0x00000002
+    // #define  NT_FREEBSD_FCTL_STKGAP_DISABLE  0x00000004
+    OS << "    Feature flags: 0x"
+       << utohexstr(
+              support::endian::read32<ELFT::TargetEndianness>(Desc.data()));
+    break;
+  }
+  OS << '\n';
+  return true;
+}
+
 struct AMDNote {
   std::string Type;
   std::string Value;
 };
 
 template <typename ELFT>
 static AMDNote getAMDNote(uint32_t NoteType, ArrayRef<uint8_t> Desc) {
   switch (NoteType) {
for (const CoreFileMapping &Mapping : Note.Mappings) {
     OS << "    " << format_hex(Mapping.Start, FieldWidth) << "  "
        << format_hex(Mapping.End, FieldWidth) << "  "
        << format_hex(Mapping.Offset, FieldWidth) << "\n        "
        << Mapping.Filename << '\n';
   }
 }
 
 template <class ELFT>
 void GNUStyle<ELFT>::printNotes(const ELFFile<ELFT> *Obj) {
   auto PrintHeader = [&](const typename ELFT::Off Offset,
                          const typename ELFT::Addr Size) {
     OS << "Displaying notes found at file offset " << format_hex(Offset, 10)
        << " with length " << format_hex(Size, 10) << ":\n"
        << "  Owner                Data size \tDescription\n";
   };
 
   auto ProcessNote = [&](const Elf_Note &Note) {
     StringRef Name = Note.getName();
     ArrayRef<uint8_t> Descriptor = Note.getDesc();
     Elf_Word Type = Note.getType();
-
+    bool IsCore = Obj->getHeader()->e_type == ELF::ET_CORE;
     // Print the note owner/type.
     OS << "  " << left_justify(Name, 20) << ' '
        << format_hex(Descriptor.size(), 10) << '\t';
     if (Name == "GNU") {
       OS << getGNUNoteTypeName(Type) << '\n';
     } else if (Name == "FreeBSD") {
-      OS << getFreeBSDNoteTypeName(Type) << '\n';
+      OS << getFreeBSDNoteTypeName(Type, IsCore) << '\n';
     } else if (Name == "AMD") {
       OS << getAMDNoteTypeName(Type) << '\n';
     } else if (Name == "AMDGPU") {
       OS << getAMDGPUNoteTypeName(Type) << '\n';
     } else {
-      StringRef NoteType = Obj->getHeader()->e_type == ELF::ET_CORE
-                               ? getCoreNoteTypeName(Type)
-                               : getGenericNoteTypeName(Type);
+      StringRef NoteType =
+          IsCore ? getCoreNoteTypeName(Type) : getGenericNoteTypeName(Type);
       if (!NoteType.empty())
         OS << NoteType << '\n';
       else
         OS << "Unknown note type: (" << format_hex(Type, 10) << ")\n";
     }
 
     // Print the description, or fallback to printing raw bytes for unknown
     // owners.
     if (Name == "GNU") {
       if (printGNUNote<ELFT>(OS, Type, Descriptor))
         return;
+    } else if (Name == "FreeBSD") {
+      if (printFreeBSDNote<ELFT>(OS, Type, Descriptor, IsCore))
+        return;
     } else if (Name == "AMD") {
       const AMDNote N = getAMDNote<ELFT>(Type, Descriptor);
       if (!N.Type.empty()) {
         OS << "    " << N.Type << ":\n        " << N.Value << '\n';
         return;
       }
     } else if (Name == "AMDGPU") {
       const AMDGPUNote N = getAMDGPUNote<ELFT>(Type, Descriptor);
case ELF::NT_GNU_PROPERTY_TYPE_0:
     ListScope D(W, "Property");
     for (const auto &Property : getGNUPropertyList<ELFT>(Desc))
       W.printString(Property);
     break;
   }
   return true;
 }
 
+template <typename ELFT>
+static bool printFreeBSDNoteLLVMStyle(uint32_t NoteType, ArrayRef<uint8_t> Desc,
+                                      ScopedPrinter &W, bool IsCore) {
+  if (IsCore)
+    return false; // No pretty-printing yet
+  switch (NoteType) {
+  default:
+    return false;
+  case ELF::NT_FREEBSD_ABI_TAG:
+    if (Desc.size() != 4) {
+      W.printString("ABI", "<corrupt FREEBSD_ABI_TAG>");
+      return false; // Print the raw data
+    }
+    W.printNumber("ABI",
+                  support::endian::read32<ELFT::TargetEndianness>(Desc.data()));
+    break;
+  case ELF::NT_FREEBSD_FEATURE_CTL:
+    if (Desc.size() != 4) {
+      W.printString("ABI", "<corrupt FREEBSD_FEATURE_CTL>");
+      return false; // Print the raw data
+    }
+    W.printHex("Flags",
+               support::endian::read32<ELFT::TargetEndianness>(Desc.data()));
+    // TODO: pretty-print these values:
+    // #define  NT_FREEBSD_FCTL_ASLR_DISABLE  0x00000001
+    // #define  NT_FREEBSD_FCTL_PROTMAX_DISABLE 0x00000002
+    // #define  NT_FREEBSD_FCTL_STKGAP_DISABLE  0x00000004
+    break;
+  }
+  return true;
+}
+
 static void printCoreNoteLLVMStyle(const CoreNote &Note, ScopedPrinter &W) {
   W.printNumber("Page Size", Note.PageSize);
   for (const CoreFileMapping &Mapping : Note.Mappings) {
     ListScope D(W, "Mapping");
     W.printHex("Start", Mapping.Start);
     W.printHex("End", Mapping.End);
     W.printHex("Offset", Mapping.Offset);
     W.printString("Filename", Mapping.Filename);
auto PrintHeader = [&](const typename ELFT::Off Offset,
     W.printHex("Size", Size);
   };
 
   auto ProcessNote = [&](const Elf_Note &Note) {
     DictScope D2(W, "Note");
     StringRef Name = Note.getName();
     ArrayRef<uint8_t> Descriptor = Note.getDesc();
     Elf_Word Type = Note.getType();
+    bool IsCore = Obj->getHeader()->e_type == ELF::ET_CORE;
 
     // Print the note owner/type.
     W.printString("Owner", Name);
     W.printHex("Data size", Descriptor.size());
     if (Name == "GNU") {
       W.printString("Type", getGNUNoteTypeName(Type));
     } else if (Name == "FreeBSD") {
-      W.printString("Type", getFreeBSDNoteTypeName(Type));
+      W.printString("Type", getFreeBSDNoteTypeName(Type, IsCore));
     } else if (Name == "AMD") {
       W.printString("Type", getAMDNoteTypeName(Type));
     } else if (Name == "AMDGPU") {
       W.printString("Type", getAMDGPUNoteTypeName(Type));
     } else {
-      StringRef NoteType = Obj->getHeader()->e_type == ELF::ET_CORE
-                               ? getCoreNoteTypeName(Type)
-                               : getGenericNoteTypeName(Type);
+      StringRef NoteType =
+          IsCore ? getCoreNoteTypeName(Type) : getGenericNoteTypeName(Type);
       if (!NoteType.empty())
         W.printString("Type", NoteType);
       else
         W.printString("Type",
                       "Unknown (" + to_string(format_hex(Type, 10)) + ")");
     }
 
     // Print the description, or fallback to printing raw bytes for unknown
     // owners.
     if (Name == "GNU") {
       if (printGNUNoteLLVMStyle<ELFT>(Type, Descriptor, W))
         return;
+    } else if (Name == "FreeBSD") {
+      if (printFreeBSDNoteLLVMStyle<ELFT>(Type, Descriptor, W, IsCore))
+        return;
     } else if (Name == "AMD") {
       const AMDNote N = getAMDNote<ELFT>(Type, Descriptor);
       if (!N.Type.empty()) {
         W.printString(N.Type, N.Value);
         return;
       }
     } else if (Name == "AMDGPU") {
       const AMDGPUNote N = getAMDGPUNote<ELFT>(Type, Descriptor);
       if (!N.Type.empty()) {
         W.printString(N.Type, N.Value);