[RFC] Collision between NT_GNU_BUILD_ATTRIBUTE_OPEN and NT_PPC_VMX

[Gustavo Romero]

Hi,

After commit 9ef920e, "Add support for displaying and merging GNU_BUILD_NOTEs.",
coredump file generated on PPC64 and displayed with 'binutils/readelf -n' shows
errors in VMX/Altivec registers note section like:

  readelf: Error: unrecognised attribute type in name field: 76
<unknown name type>  0x00000220	NT_PPC_VMX (ppc Altivec registers)
readelf: Error:     <invalid description size: 220>
    <invalid descsz>

Before it was:

LINUX                0x00000220	NT_PPC_VMX (ppc Altivec registers)

because NT_GNU_BUILD_ATTRIBUTE_OPEN (introduced by the aforementioned commit)
has the same value as NT_PPC_VMX:

$ grep 0x100 include/elf/common.h
#define NT_PPC_VMX	0x100		/* PowerPC Altivec/VMX registers */
#define NT_GNU_BUILD_ATTRIBUTE_OPEN	0x100

If my understanding is correct about GNU_BUILD_NOTEs, it's just useful on
run-time or dynamic / static linking and will never be present in a coredump
file. If that holds I suggest the following simple fix:

@@ -17477,8 +17503,8 @@ process_note (Elf_Internal_Note *  pnote,

   printf ("  ");

-  if (pnote->type == NT_GNU_BUILD_ATTRIBUTE_OPEN
-      || pnote->type == NT_GNU_BUILD_ATTRIBUTE_FUNC)
+  if (elf_header.e_type != ET_CORE && (pnote->type == NT_GNU_BUILD_ATTRIBUTE_OPEN
+      || pnote->type == NT_GNU_BUILD_ATTRIBUTE_FUNC))
     print_gnu_build_attribute_name (pnote);
   else
     print_symbol (-20, name);
@@ -17496,8 +17522,8 @@ process_note (Elf_Internal_Note *  pnote,
     return print_stapsdt_note (pnote);
   else if (const_strneq (pnote->namedata, "CORE"))
     return print_core_note (pnote);
-  else if (pnote->type == NT_GNU_BUILD_ATTRIBUTE_OPEN
-          || pnote->type == NT_GNU_BUILD_ATTRIBUTE_FUNC)
+  else if (elf_header.e_type != ET_CORE && (pnote->type == NT_GNU_BUILD_ATTRIBUTE_OPEN
+          || pnote->type == NT_GNU_BUILD_ATTRIBUTE_FUNC))
     return print_gnu_build_attribute_description (pnote, file);

If that change is upvoted I'll send a formal patch for review.

Thank you.


Best regards,
Gustavo