[PATCH] elf: Report property change when merging properties

["H.J. Lu" <hjl dot tools at gmail dot com>]

With merging properties, report property change in linker map file, like

Merging property 0xc0000002 in foo.o (0x1) and bar.o (None): removed

bfd/

	elf-properties.c (elf_merge_gnu_property_list): Updated.  Report
	property change in linker map file.
	(_bfd_elf_link_setup_gnu_properties): Pass abfd to
	elf_merge_gnu_property_list.

ld/

	* NEWS: Updated for property change report.
	* ld.tex: Document property change report.
	* testsuite/ld-x86-64/property-x86-ibt1a-x32.d: Check linker map
	file.
	* testsuite/ld-x86-64/property-x86-ibt1a.d: Likewise.
	* testsuite/ld-x86-64/property-x86-ibt1a.map: New file.
---
 bfd/elf-properties.c                          | 95 +++++++++++++++----
 ld/NEWS                                       |  2 +
 ld/ld.texi                                    | 22 +++++
 .../ld-x86-64/property-x86-ibt1a-x32.d        |  3 +-
 ld/testsuite/ld-x86-64/property-x86-ibt1a.d   |  3 +-
 ld/testsuite/ld-x86-64/property-x86-ibt1a.map |  5 +
 6 files changed, 108 insertions(+), 22 deletions(-)
 create mode 100644 ld/testsuite/ld-x86-64/property-x86-ibt1a.map

diff --git a/bfd/elf-properties.c b/bfd/elf-properties.c
index 861db73170..2119170017 100644
--- a/bfd/elf-properties.c
+++ b/bfd/elf-properties.c
@@ -261,47 +261,102 @@ elf_find_and_remove_property (elf_property_list **listp,
   return NULL;
 }
 
-/* Merge GNU property list *LISTP with ABFD.  */
+/* Merge GNU property list *LISTP in ABFD with FIRST_PBFD.  */
 
 static void
-elf_merge_gnu_property_list (struct bfd_link_info *info, bfd *abfd,
-			     elf_property_list **listp)
+elf_merge_gnu_property_list (struct bfd_link_info *info, bfd *first_pbfd,
+			     bfd *abfd, elf_property_list **listp)
 {
   elf_property_list *p, **lastp;
   elf_property *pr;
+  bfd_boolean number_p;
+  bfd_vma number = 0;
 
-  /* Merge each GNU property in ABFD with the one on *LISTP.  */
-  lastp = &elf_properties (abfd);
+  /* Merge each GNU property in FIRST_PBFD with the one on *LISTP.  */
+  lastp = &elf_properties (first_pbfd);
   for (p = *lastp; p; p = p->next)
     {
+      if (p->property.pr_kind == property_number)
+	{
+	  number_p = TRUE;
+	  number = p->property.u.number;
+	}
+      else
+	number_p = FALSE;
       pr = elf_find_and_remove_property (listp, p->property.pr_type);
       /* Pass NULL to elf_merge_gnu_properties for the property which
 	 isn't on *LISTP.  */
-      elf_merge_gnu_properties (info, abfd, &p->property, pr);
+      elf_merge_gnu_properties (info, first_pbfd, &p->property, pr);
       if (p->property.pr_kind == property_remove)
 	{
 	  /* Remove this property.  */
 	  *lastp = p->next;
+	  if (number_p)
+	    {
+	      if (pr != NULL)
+		info->callbacks->minfo
+		  (_("Merging property %W in %pB (0x%v) and %pB "
+		     "(0x%v): removed\n"),
+		   (bfd_vma) p->property.pr_type, first_pbfd, number,
+		   abfd, pr->u.number);
+	      else
+		info->callbacks->minfo
+		  (_("Merging property %W in %pB (0x%v) and %pB "
+		     "(None): removed\n"),
+		   (bfd_vma) p->property.pr_type, first_pbfd, number,
+		   abfd);
+	    }
+	  else
+	    info->callbacks->minfo
+	      (_("Merging property %W in %pB and %pB: removed\n"),
+	       (bfd_vma) p->property.pr_type, first_pbfd, abfd);
 	  continue;
 	}
+      if (number_p)
+	{
+	  if (pr != NULL)
+	    info->callbacks->minfo
+	      (_("Merging property %W in %pB (0x%v) and %pB (0x%v): 0x%v\n"),
+	       (bfd_vma) p->property.pr_type, first_pbfd, number, abfd,
+	       pr->u.number, p->property.u.number);
+	  else
+	    info->callbacks->minfo
+	      (_("Merging property %W in %pB (0x%v) and %pB (None): 0x%v\n"),
+	       (bfd_vma) p->property.pr_type, first_pbfd, number, abfd,
+	       p->property.u.number);
+	}
       lastp = &p->next;
     }
 
-  /* Merge the remaining properties on *LISTP with ABFD.  */
+  /* Merge the remaining properties on *LISTP with FIRST_PBFD.  */
   for (p = *listp; p != NULL; p = p->next)
-    if (elf_merge_gnu_properties (info, abfd, NULL, &p->property))
-      {
-	if (p->property.pr_type == GNU_PROPERTY_NO_COPY_ON_PROTECTED)
-	  elf_has_no_copy_on_protected (abfd) = TRUE;
+    {
+      if (p->property.pr_kind == property_number)
+	{
+	  number_p = TRUE;
+	  number = p->property.u.number;
+	}
+      else
+	number_p = FALSE;
 
-	pr = _bfd_elf_get_property (abfd, p->property.pr_type,
-				    p->property.pr_datasz);
-	/* It must be a new property.  */
-	if (pr->pr_kind != property_unknown)
-	  abort ();
-	/* Add a new property.  */
-	*pr = p->property;
-      }
+      if (elf_merge_gnu_properties (info, first_pbfd, NULL, &p->property))
+	{
+	  if (p->property.pr_type == GNU_PROPERTY_NO_COPY_ON_PROTECTED)
+	    elf_has_no_copy_on_protected (first_pbfd) = TRUE;
+
+	  pr = _bfd_elf_get_property (first_pbfd, p->property.pr_type,
+				      p->property.pr_datasz);
+	  /* It must be a new property.  */
+	  if (pr->pr_kind != property_unknown)
+	    abort ();
+	  /* Add a new property.  */
+	  *pr = p->property;
+	}
+      else if (number_p)
+	info->callbacks->minfo
+	  (_("Merging property %W in %pB (None) and %pB (%0xv): removed\n"),
+	   (bfd_vma) p->property.pr_type, first_pbfd, abfd, number);
+    }
 }
 
 /* Get GNU property section size.  */
@@ -470,7 +525,7 @@ _bfd_elf_link_setup_gnu_properties (struct bfd_link_info *info)
 	   when all properties are from ELF objects with different
 	   machine code or class.  */
 	if (first_pbfd != NULL)
-	  elf_merge_gnu_property_list (info, first_pbfd, listp);
+	  elf_merge_gnu_property_list (info, first_pbfd, abfd, listp);
 
 	if (list != NULL)
 	  {
diff --git a/ld/NEWS b/ld/NEWS
index e2e87defee..502966635e 100644
--- a/ld/NEWS
+++ b/ld/NEWS
@@ -1,5 +1,7 @@
 -*- text -*-
 
+* Report property change in linker map file when merging GNU properties.
+
 * Add support for the C-SKY processor series.
 
 Changes in 2.31:
diff --git a/ld/ld.texi b/ld/ld.texi
index 985c591d6a..f5d0245dd7 100644
--- a/ld/ld.texi
+++ b/ld/ld.texi
@@ -759,6 +759,28 @@ option is used:
 
 See @ref{Expressions} for more information about expressions in linker
 scripts.
+
+@item How GNU properties are merged.
+
+When linker merges input .note.gnu.property sections into one output
+.note.gnu.property section, some properties are removed or updated,
+which are reported in the link map as
+
+@smallexample
+Merging property 0xc0000002 in foo.o (0x1) and bar.o (None): removed
+@end smallexample
+
+It indicates that property 0xc0000002 is removed from output when
+merging properties in  @file{foo.o}, whose property 0xc0000002 value
+is 0x1, and @file{bar.o}, which doesn't have property 0xc0000002.
+
+@smallexample
+Merging property 0xc0010001 in foo.o (0x1) and bar.o (0x1): 0x1
+@end smallexample
+
+It indicates that property 0xc0010001 value is 0x1 in output when
+merging properties in  @file{foo.o}, whose 0xc0010001 property value
+is 0x1, and @file{bar.o}, whose 0xc0010001 property value is 0x1.
 @end itemize
 
 @kindex -n
diff --git a/ld/testsuite/ld-x86-64/property-x86-ibt1a-x32.d b/ld/testsuite/ld-x86-64/property-x86-ibt1a-x32.d
index 7a95401ac3..d05ab1dce5 100644
--- a/ld/testsuite/ld-x86-64/property-x86-ibt1a-x32.d
+++ b/ld/testsuite/ld-x86-64/property-x86-ibt1a-x32.d
@@ -1,8 +1,9 @@
 #source: property-x86-empty.s
 #source: property-x86-ibt.s
 #as: --x32 -mx86-used-note=yes
-#ld: -r -m elf32_x86_64
+#ld: -r -m elf32_x86_64 -Map tmpdir/property-x86-ibt1a-x32.map
 #readelf: -n
+#map: property-x86-ibt1a.map
 
 Displaying notes found in: .note.gnu.property
   Owner                 Data size	Description
diff --git a/ld/testsuite/ld-x86-64/property-x86-ibt1a.d b/ld/testsuite/ld-x86-64/property-x86-ibt1a.d
index e989a8a817..f8d6a063b4 100644
--- a/ld/testsuite/ld-x86-64/property-x86-ibt1a.d
+++ b/ld/testsuite/ld-x86-64/property-x86-ibt1a.d
@@ -1,8 +1,9 @@
 #source: property-x86-empty.s
 #source: property-x86-ibt.s
 #as: --64 -defsym __64_bit__=1 -mx86-used-note=yes
-#ld: -r -melf_x86_64
+#ld: -r -melf_x86_64 -Map tmpdir/property-x86-ibt1a.map
 #readelf: -n
+#map: property-x86-ibt1a.map
 
 Displaying notes found in: .note.gnu.property
   Owner                 Data size	Description
diff --git a/ld/testsuite/ld-x86-64/property-x86-ibt1a.map b/ld/testsuite/ld-x86-64/property-x86-ibt1a.map
new file mode 100644
index 0000000000..43b91abcf5
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/property-x86-ibt1a.map
@@ -0,0 +1,5 @@
+#...
+Merging property 0xc0000002 in tmpdir/property-x86-empty.o \(0x0\) and tmpdir/property-x86-ibt.o \(0x1\): removed
+Merging property 0xc0010000 in tmpdir/property-x86-empty.o \(0x80000000\) and tmpdir/property-x86-ibt.o \(0x80000000\): 0x80000000
+Merging property 0xc0010001 in tmpdir/property-x86-empty.o \(0x1\) and tmpdir/property-x86-ibt.o \(0x1\): 0x1
+#pass
-- 
2.19.1