[llvm-readobj] Add some generic notes (e.g. NT_VERSION)

[rupprecht]

Summary

Support reading notes that don't have a standard note name.

[MaskRay]

llvm/tools/llvm-readobj/ELFDumper.cpp

3522

Is the lowercase used here intentional?

[rupprecht]

llvm/tools/llvm-readobj/ELFDumper.cpp

3522

yup

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=blobdiff;f=binutils/readelf.c;h=ae1cda9a7bd54b85f085d1bb48f8b2c4bf5f0d46;hp=f221cce32a948b489977cc3199f5da1a66413fb3;hb=6f156d7a4ad1c245b357dc50f63f3564d397839e;hpb=9f757bf7fcb8834ead780e0c4a76d6029b1402c2

I don't know why.

llvm/include/llvm/BinaryFormat/ELF.h

enum {
   NT_FREEBSD_PROCSTAT_GROUPS = 11,
   NT_FREEBSD_PROCSTAT_UMASK = 12,
   NT_FREEBSD_PROCSTAT_RLIMIT = 13,
   NT_FREEBSD_PROCSTAT_OSREL = 14,
   NT_FREEBSD_PROCSTAT_PSSTRINGS = 15,
   NT_FREEBSD_PROCSTAT_AUXV = 16,
 };
 
+// Generic note types
+enum : unsigned {
+  NT_VERSION = 1,
+  NT_ARCH = 2,
+  NT_GNU_BUILD_ATTRIBUTE_OPEN = 0x100,
+  NT_GNU_BUILD_ATTRIBUTE_FUNC = 0x101,
+};
+
 enum {
   NT_GNU_ABI_TAG = 1,
   NT_GNU_HWCAP = 2,
   NT_GNU_BUILD_ID = 3,
   NT_GNU_GOLD_VERSION = 4,
   NT_GNU_PROPERTY_TYPE_0 = 5,
 };
 

llvm/test/tools/llvm-readobj/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
+
+// GNU:      Displaying notes found at file offset 0x00000040 with length 0x00000010:
+// GNU-NEXT:   Owner                 Data size       Description
+// GNU-NEXT:   XYZ                  0x00000000       NT_VERSION (version)
+
+// GNU:      Displaying notes found at file offset 0x00000050 with length 0x00000010:
+// GNU-NEXT:   Owner                 Data size       Description
+// GNU-NEXT:   XYZ                  0x00000000       NT_ARCH (architecture)
+
+// GNU:      Displaying notes found at file offset 0x00000060 with length 0x00000010:
+// GNU-NEXT:   Owner                 Data size       Description
+// GNU-NEXT:   XYZ                  0x00000000       OPEN
+
+// GNU:      Displaying notes found at file offset 0x00000070 with length 0x00000010:
+// GNU-NEXT:   Owner                 Data size       Description
+// GNU-NEXT:   XYZ                  0x00000000       func
+
+// LLVM:      Notes [
+// LLVM-NEXT:   NoteSection {
+// LLVM-NEXT:     Offset: 0x40
+// LLVM-NEXT:     Size: 0x10
+// LLVM-NEXT:     Note {
+// LLVM-NEXT:       Owner: XYZ
+// LLVM-NEXT:       Data size: 0x0
+// LLVM-NEXT:       Type: NT_VERSION (version)
+// LLVM-NEXT:     }
+// LLVM-NEXT:   }
+// LLVM-NEXT:   NoteSection {
+// LLVM-NEXT:     Offset: 0x50
+// LLVM-NEXT:     Size: 0x10
+// LLVM-NEXT:     Note {
+// LLVM-NEXT:       Owner: XYZ
+// LLVM-NEXT:       Data size: 0x0
+// LLVM-NEXT:       Type: NT_ARCH (architecture)
+// LLVM-NEXT:     }
+// LLVM-NEXT:   }
+// LLVM-NEXT:   NoteSection {
+// LLVM-NEXT:     Offset: 0x60
+// LLVM-NEXT:     Size: 0x10
+// LLVM-NEXT:     Note {
+// LLVM-NEXT:       Owner: XYZ
+// LLVM-NEXT:       Data size: 0x0
+// LLVM-NEXT:       Type: OPEN
+// LLVM-NEXT:     }
+// LLVM-NEXT:   }
+// LLVM-NEXT:   NoteSection {
+// LLVM-NEXT:     Offset: 0x70
+// LLVM-NEXT:     Size: 0x10
+// LLVM-NEXT:     Note {
+// LLVM-NEXT:       Owner: XYZ
+// LLVM-NEXT:       Data size: 0x0
+// LLVM-NEXT:       Type: func
+// LLVM-NEXT:     }
+// LLVM-NEXT:   }
+// LLVM-NEXT: ]
+
+.section ".note.version", "a"
+  .align 4
+  .long 4 /* namesz */
+  .long 0 /* descsz */
+  .long 1 /* type = NT_VERSION */
+  .asciz "XYZ"
+.section ".note.arch", "a"
+  .align 4
+  .long 4 /* namesz */
+  .long 0 /* descsz */
+  .long 2 /* type = NT_ARCH*/
+  .asciz "XYZ"
+.section ".note.open", "a"
+  .align 4
+  .long 4 /* namesz */
+  .long 0 /* descsz */
+  .long 0x100 /* type = NT_GNU_BUILD_ATTRIBUTE_OPEN*/
+  .asciz "XYZ"
+.section ".note.func", "a"
+  .align 4
+  .long 4 /* namesz */
+  .long 0 /* descsz */
+  .long 0x101 /* type = NT_GNU_BUILD_ATTRIBUTE_FUNC*/
+  .asciz "XYZ"

llvm/tools/llvm-readobj/ELFDumper.cpp

void GNUStyle<ELFT>::printCGProfile(const ELFFile<ELFT> *Obj) {
   OS << "GNUStyle::printCGProfile not implemented\n";
 }
 
 template <class ELFT>
 void GNUStyle<ELFT>::printAddrsig(const ELFFile<ELFT> *Obj) {
     OS << "GNUStyle::printAddrsig not implemented\n";
 }
 
+static StringRef getGenericNoteTypeName(const uint32_t NT) {
+  static const struct {
+    uint32_t ID;
+    const char *Name;
+  } Notes[] = {
+      {ELF::NT_VERSION, "NT_VERSION (version)"},
+      {ELF::NT_ARCH, "NT_ARCH (architecture)"},
+      {ELF::NT_GNU_BUILD_ATTRIBUTE_OPEN, "OPEN"},
+      {ELF::NT_GNU_BUILD_ATTRIBUTE_FUNC, "func"},
+  };
+
+  for (const auto &Note : Notes)
+    if (Note.ID == NT)
+      return Note.Name;
+
+  return "";
+}
+
 static std::string getGNUNoteTypeName(const uint32_t NT) {
   static const struct {
     uint32_t ID;
     const char *Name;
   } Notes[] = {
       {ELF::NT_GNU_ABI_TAG, "NT_GNU_ABI_TAG (ABI version tag)"},
       {ELF::NT_GNU_HWCAP, "NT_GNU_HWCAP (DSO-supplied software HWCAP info)"},
       {ELF::NT_GNU_BUILD_ID, "NT_GNU_BUILD_ID (unique build ID bitstring)"},
if (Name == "GNU") {
       if (!N.Type.empty())
         OS << "    " << N.Type << ":\n        " << N.Value << '\n';
     } else if (Name == "AMDGPU") {
       OS << getAMDGPUNoteTypeName(Type) << '\n';
       const AMDGPUNote N = getAMDGPUNote<ELFT>(Type, Descriptor);
       if (!N.Type.empty())
         OS << "    " << N.Type << ":\n        " << N.Value << '\n';
     } else {
+      StringRef NoteType = getGenericNoteTypeName(Type);
+      if (!NoteType.empty())
+        OS << NoteType;
+      else
         OS << "Unknown note type: (" << format_hex(Type, 10) << ')';
     }
     OS << '\n';
   };
 
   if (Obj->getHeader()->e_type == ELF::ET_CORE) {
     for (const auto &P : unwrapOrError(Obj->program_headers())) {
       if (P.p_type != PT_NOTE)
         continue;
if (Name == "GNU") {
       if (!N.Type.empty())
         W.printString(N.Type, N.Value);
     } else if (Name == "AMDGPU") {
       W.printString("Type", getAMDGPUNoteTypeName(Type));
       const AMDGPUNote N = getAMDGPUNote<ELFT>(Type, Descriptor);
       if (!N.Type.empty())
         W.printString(N.Type, N.Value);
     } else {
+      StringRef NoteType = getGenericNoteTypeName(Type);
+      if (!NoteType.empty())
+        W.printString("Type", NoteType);
+      else
         W.printString("Type",
                       "Unknown (" + to_string(format_hex(Type, 10)) + ")");
     }
   };
 
   if (Obj->getHeader()->e_type == ELF::ET_CORE) {
     for (const auto &P : unwrapOrError(Obj->program_headers())) {
       if (P.p_type != PT_NOTE)
         continue;
       DictScope D(W, "NoteSection");