[llvm-readobj] Print empty line between note sections in GNU mode

[arichardson]

Summary

This matches GNU binutils.

[jhenderson]

Does GNU readelf print an empty line after the last entry too? If so, LGTM.

[arichardson]

This comment was removed by arichardson.

[arichardson]

Match GNU exactly: no newline after the last notes section.

[jhenderson]

LGTM.

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

22

This is slightly surprising now, though probably harmless.

[arichardson]

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

22

I think FileCheck also matches EOF for -EMPTY? Or possibly it matches the \n after func.

[jhenderson]

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

22

Yes, it'll be something like the matching EOF line (after all, there is no output at that point). It's not really worth worrying about though. I'm not sure if there's a clear fix. Maybe a CHECK-NOT: {{.}} would make more sense?

[arichardson]

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

22

That seems to do the same (since the last match ends before the newline. I can't find a way to make it fail if there is an extra newline (other than e.g. piping to hexdump).

This also works fine if the output ends in \n\n:

// GNU-NEXT:   XYZ                  0x00000000	func{{$}}
// GNU-NOT: {{.}}

[jhenderson]

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

22

Fair enough. Something to look at another time, I guess. I'd just delete this line and call it good then, but happy for you to do something else too.

llvm/test/tools/llvm-readobj/ELF/note-amd.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 in: .note.no.desc
 // GNU-NEXT:   Owner                Data size        Description
 // GNU-NEXT:   AMD                  0x00000000       NT_AMD_AMDGPU_HSA_METADATA (HSA Metadata)
 // GNU-NEXT:     HSA Metadata:
-// GNU-NEXT: {{^ +$}}
+// GNU-NEXT: {{^        $}}
 // GNU-NEXT:   AMD                  0x00000000       NT_AMD_AMDGPU_ISA (ISA Version)
 // GNU-NEXT:     ISA Version:
-// GNU-NEXT: {{^ +$}}
+// GNU-NEXT: {{^        $}}
+// GNU-EMPTY:
 // GNU-NEXT: Displaying notes found in: .note.desc
 // GNU-NEXT:   Owner                Data size        Description
 // GNU-NEXT:   AMD                  0x0000000a       NT_AMD_AMDGPU_HSA_METADATA (HSA Metadata)
 // GNU-NEXT:     HSA Metadata:
 // GNU-NEXT:     meta_blah
 // GNU-NEXT:   AMD                  0x00000009       NT_AMD_AMDGPU_ISA (ISA Version)
 // GNU-NEXT:     ISA Version:
 // GNU-NEXT:     isa_blah
+// GNU-EMPTY:
 // GNU-NEXT: Displaying notes found in: .note.other
 // GNU-NEXT:   Owner                Data size        Description
 // GNU-NEXT:   AMD                  0x00000000       NT_AMD_AMDGPU_PAL_METADATA (PAL Metadata)
+// GNU-EMPTY:
 
 // LLVM:      Notes [
 // LLVM-NEXT:   NoteSection {
 // LLVM-NEXT:     Name: .note.no.desc
 // LLVM-NEXT:     Offset:
 // LLVM-NEXT:     Size:
 // LLVM-NEXT:     Note {
 // LLVM-NEXT:       Owner: AMD

llvm/test/tools/llvm-readobj/ELF/note-amdgpu-invalid.s

 # GNU-NEXT:     .max_flat_workgroup_size: 8
 # GNU-NEXT:     .name:           foo
 # GNU-NEXT:     .private_segment_fixed_size: 3
 # GNU-NEXT:     .sgpr_count:     6
 # GNU-NEXT:     .symbol:         foo
 # GNU-NEXT:     .vgpr_count:     7
 # GNU-NEXT:     .wavefront_size: 5
 # GNU-NEXT: ...
+# GNU-EMPTY:
 
 # LLVM:      Notes [
 # LLVM-NEXT:   NoteSection {
 # LLVM-NEXT:     Name: .note.foo
 # LLVM-NEXT:     Offset: 0x40
 # LLVM-NEXT:     Size: 0xE8
 # LLVM-NEXT:     Note {
 # LLVM-NEXT:       Owner: AMDGPU

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

 # GNU-NEXT:     Page size: 4096
 # GNU-NEXT:                  Start                 End         Page Offset
 # GNU-NEXT:     0x0000000000001000  0x0000000000002000  0x0000000000003000
 # GNU-NEXT:         /path/to/a.out
 # GNU-NEXT:     0x0000000000004000  0x0000000000005000  0x0000000000006000
 # GNU-NEXT:         /path/to/libc.so
 # GNU-NEXT:     0x0000000000007000  0x0000000000008000  0x0000000000009000
 # GNU-NEXT:         [stack]
-# GNU-NOT:  {{.}}
+# GNU-EMPTY:
 
 # LLVM:      Notes [
 # LLVM-NEXT:   NoteSection {
 # LLVM-NEXT:     Name: <?>
 # LLVM-NEXT:     Offset:
 # LLVM-NEXT:     Size:
 # LLVM-NEXT:     Note {
 # LLVM-NEXT:       Owner: CORE

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

 
 ## Check an arbitrary unknown type.
 # RUN: yaml2obj %s -DTYPE=0x12345678 -o %t50.o
 # RUN: llvm-readelf --notes %t50.o | FileCheck %s --check-prefix=CHECK-GNU  -DDESC="Unknown note type: (0x12345678)"
 # RUN: llvm-readobj --notes %t50.o | FileCheck %s --check-prefix=CHECK-LLVM -DDESC="Unknown (0x12345678)"
 
 # CHECK-GNU:      Owner Data size  Description
 # CHECK-GNU-NEXT: CORE  0x00000000 [[DESC]]
+# CHECK-GNU-EMPTY:
 
 # CHECK-LLVM:      Note {
 # CHECK-LLVM-NEXT:   Owner: CORE
 # CHECK-LLVM-NEXT:   Data size: 0x0
 # CHECK-LLVM-NEXT:   Type: [[DESC]]
 # CHECK-LLVM-NEXT: }
 
 --- !ELF

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 in: .note.foo
 // GNU-NEXT:   Owner                Data size        Description
 // GNU-NEXT:   FreeBSD              0x00000000       NT_THRMISC (thrmisc structure)
 // GNU-NEXT:   FreeBSD              0x00000000       NT_PROCSTAT_PROC (proc data)
+// GNU-EMPTY:
 // GNU-NEXT: Displaying notes found in: .note.bar
 // GNU-NEXT:   Owner                Data size        Description
 // GNU-NEXT:   FreeBSD              0x00000000       NT_PROCSTAT_FILES (files data)
+// GNU-EMPTY:
 // GNU-NEXT: Displaying notes found in: .note.baz
 // 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
+// GNU-EMPTY:
 
 // LLVM:      Notes [
 // LLVM-NEXT:   NoteSection {
 // LLVM-NEXT:     Name: .note.foo
 // LLVM-NEXT:     Offset:
 // LLVM-NEXT:     Size:
 // LLVM-NEXT:     Note {
 // LLVM-NEXT:       Owner: FreeBSD

llvm/test/tools/llvm-readobj/ELF/note-generic.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
+// RUN: llvm-readobj --notes %t.o | FileCheck %s --check-prefix=LLVM --strict-whitespace
+// RUN: llvm-readelf --notes %t.o | FileCheck %s --check-prefix=GNU --strict-whitespace
 
-// GNU:      Displaying notes found in: .note.version
-// GNU-NEXT:   Owner                 Data size       Description
-// GNU-NEXT:   XYZ                  0x00000000       NT_VERSION (version)
-
-// GNU:      Displaying notes found in: .note.arch
-// GNU-NEXT:   Owner                 Data size       Description
-// GNU-NEXT:   XYZ                  0x00000000       NT_ARCH (architecture)
-
-// GNU:      Displaying notes found in: .note.open
-// GNU-NEXT:   Owner                 Data size       Description
-// GNU-NEXT:   XYZ                  0x00000000       OPEN
-
-// GNU:      Displaying notes found in: .note.func
-// GNU-NEXT:   Owner                 Data size       Description
-// GNU-NEXT:   XYZ                  0x00000000       func
+// GNU:      Displaying notes found in: .note.version{{$}}
+// GNU-NEXT:   Owner                Data size   Description
+// GNU-NEXT:   XYZ                  0x00000000  NT_VERSION (version)
+// GNU-EMPTY:
+// GNU-NEXT: Displaying notes found in: .note.arch{{$}}
+// GNU-NEXT:   Owner                Data size   Description
+// GNU-NEXT:   XYZ                  0x00000000  NT_ARCH (architecture)
+// GNU-EMPTY:
+// GNU-NEXT: Displaying notes found in: .note.open{{$}}
+// GNU-NEXT:   Owner                Data size   Description
+// GNU-NEXT:   XYZ                  0x00000000  OPEN
+// GNU-EMPTY:
+// GNU-NEXT: Displaying notes found in: .note.func{{$}}
+// GNU-NEXT:   Owner                Data size   Description
+// GNU-NEXT:   XYZ                  0x00000000  func
 
 // LLVM:      Notes [
 // LLVM-NEXT:   NoteSection {
 // LLVM-NEXT:     Name: .note.version
 // LLVM-NEXT:     Offset: 0x40
 // LLVM-NEXT:     Size: 0x10
 // LLVM-NEXT:     Note {
 // LLVM-NEXT:       Owner: XYZ
 // LLVM-NEXT:       Data size: 0x0

llvm/test/tools/llvm-readobj/ELF/note-unknown.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 in: .note.foo
 // GNU-NEXT:   Owner                 Data size       Description
 // GNU-NEXT:   XYZ                  0x00000000       Unknown note type: (0x00000003)
+// GNU-EMPTY:
 // GNU-NEXT: Displaying notes found in: .note.bar
 // GNU-NEXT:   Owner                 Data size       Description
 // GNU-NEXT:   XYZ                  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
+// GNU-EMPTY:
 
 // LLVM:      Notes [
 // LLVM-NEXT:   NoteSection {
 // LLVM-NEXT:     Name: .note.foo
 // LLVM-NEXT:     Offset: 0x40
 // LLVM-NEXT:     Size: 0x10
 // LLVM-NEXT:     Note {
 // LLVM-NEXT:       Owner: XYZ

llvm/tools/llvm-readobj/ELFDumper.cpp

if (Err)
       Dumper.reportUniqueWarning(
           "unable to read notes from the PT_NOTE segment with index " +
           Twine(I) + ": " + toString(std::move(Err)));
     FinishNotesFn();
   }
 }
 
 template <class ELFT> void GNUELFDumper<ELFT>::printNotes() {
+  bool IsFirstHeader = true;
   auto PrintHeader = [&](Optional<StringRef> SecName,
                          const typename ELFT::Off Offset,
                          const typename ELFT::Addr Size) {
+    // Print a newline between notes sections to match GNU readelf.
+    if (!IsFirstHeader) {
+      OS << '\n';
+    } else {
+      IsFirstHeader = false;
+    }
+
     OS << "Displaying notes found ";
 
     if (SecName)
       OS << "in: " << *SecName << "\n";
     else
       OS << "at file offset " << format_hex(Offset, 10) << " with length "
          << format_hex(Size, 10) << ":\n";