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[RFC] Collision between NT_GNU_BUILD_ATTRIBUTE_OPEN and NT_PPC_VMX

Alan Modra amodra@gmail.com
Sat Aug 12 08:14:00 GMT 2017 
On Sat, Aug 12, 2017 at 10:52:51AM +0930, Alan Modra wrote:
> On Fri, Aug 11, 2017 at 04:03:26PM -0700, H.J. Lu wrote:
> > This is wrong.  pnote->type is unique only for a given pnote->namedata.
> 
> That is true.  According to the gABI, the name is supposed to be the
> originator of the note, and the type is decoded depending on the name.
> 
> >  NT_GNU_* should be be checked for "GNU" notes.
> 
> Well, yes, but NT_GNU_BUILD_ATTRIBUTE_* doesn't use "GNU".  The
> proposal at https://fedoraproject.org/wiki/Toolchain/Watermark says
> they ought to start with "GA", and even that stretches the gABI
> description of notes, but the support and testcases Nick committed
> omit "GA".  So we don't have anything remotely like an originator
> string.  The name dives straight into data.  :-(

OK, so I thought I'd have another look at this (escaping outside
work in the garden).  It seems from the objcopy code that the "GA"
style is version 2 of these notes.  Good!

Here is what I'm going to commit.

	* readelf.c (process_note): Qualify NT_GNU_BUILD_ATTRIBUTE notes
	by name data.

diff --git a/binutils/readelf.c b/binutils/readelf.c
index 2b15f0f..0fc6562 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -17477,8 +17477,11 @@ process_note (Elf_Internal_Note *  pnote,
 
   printf ("  ");
 
-  if (pnote->type == NT_GNU_BUILD_ATTRIBUTE_OPEN
-      || pnote->type == NT_GNU_BUILD_ATTRIBUTE_FUNC)
+  if (((const_strneq (pnote->namedata, "GA")
+	&& strchr ("*$!+", pnote->namedata[2]) != NULL)
+       || strchr ("*$!+", pnote->namedata[0]) != NULL)
+      && (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 +17499,11 @@ 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 (((const_strneq (pnote->namedata, "GA")
+	     && strchr ("*$!+", pnote->namedata[2]) != NULL)
+	    || strchr ("*$!+", pnote->namedata[0]) != NULL)
+	   && (pnote->type == NT_GNU_BUILD_ATTRIBUTE_OPEN
+	       || pnote->type == NT_GNU_BUILD_ATTRIBUTE_FUNC))
     return print_gnu_build_attribute_description (pnote, file);
 
   if (pnote->descsz)

-- 
Alan Modra
Australia Development Lab, IBM
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