Improve readelf's selection of a file start symbol when displaying a gnu build attribute.

	* readelf.c (get_symbol_for_build_attribute): Skip ARM mapping
	symbols.
	(print_gnu_build_attribute_description): If no file start symbol
	could be found, look for one two bytes into the file.
	* testsuite/binutils-all/note-4-64.s: Set the address of the file
	start symbol to two bytes into the file.
	* testsuite/binutils-all/note-4-32.s: Likewise.

5 files changed, 36 insertions, 13 deletions

diff --git a/binutils/ChangeLog b/binutils/ChangeLog
index cb4e3be..eb17a42 100644
--- a/binutils/ChangeLog
+++ b/binutils/ChangeLog
@@ -1,3 +1,13 @@
+2018-03-23  Nick Clifton  <nickc@redhat.com>
+
+	* readelf.c (get_symbol_for_build_attribute): Skip ARM mapping
+	symbols.
+	(print_gnu_build_attribute_description): If no file start symbol
+	could be found, look for one two bytes into the file.
+	* testsuite/binutils-all/note-4-64.s: Set the address of the file
+	start symbol to two bytes into the file.
+	* testsuite/binutils-all/note-4-32.s: Likewise.
+
 2018-03-21  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* readelf.c (process_dynamic_section): Also dump DF_1_KMOD,
diff --git a/binutils/readelf.c b/binutils/readelf.c
index d0bd679..80075c2 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -17502,6 +17502,13 @@ get_symbol_for_build_attribute (Filedata *       filedata,
 	if (strtab[sym->st_name] == 0)
 	  continue;
 
+	/* The AArch64 and ARM architectures define mapping symbols
+	   (eg $d, $x, $t) which we want to ignore.  */
+	if (strtab[sym->st_name] == '$'
+	    && strtab[sym->st_name + 1] != 0
+	    && strtab[sym->st_name + 2] == 0)
+	  continue;
+
 	if (is_open_attr)
 	  {
 	    /* For OPEN attributes we prefer GLOBAL over LOCAL symbols
@@ -17630,6 +17637,12 @@ print_gnu_build_attribute_description (Elf_Internal_Note *  pnote,
 
   name = NULL;
   sym = get_symbol_for_build_attribute (filedata, start, is_open_attr, & name);
+  /* As of version 5 of the annobin plugin, filename symbols are biased by 2
+     in order to avoid them being confused with the start address of the
+     first function in the file...  */
+  if (sym == NULL && is_open_attr)
+    sym = get_symbol_for_build_attribute (filedata, start + 2, is_open_attr,
+					  & name);
 
   if (end == 0 && sym != NULL && sym->st_size > 0)
     end = start + sym->st_size;
diff --git a/binutils/testsuite/binutils-all/note-4-32.d b/binutils/testsuite/binutils-all/note-4-32.d
index 567af90..6c9e98e 100644
--- a/binutils/testsuite/binutils-all/note-4-32.d
+++ b/binutils/testsuite/binutils-all/note-4-32.d
@@ -7,13 +7,13 @@
 #...
 Displaying notes found in: .gnu.build.attributes
 [ 	]+Owner[ 	]+Data size[ 	]+Description
-[ 	]+GA\$<version>3p3[ 	]+0x00000008[ 	]+OPEN[ 	]+Applies to region from 0x100 to 0x110 \(note_4.s\)
-[ 	]+GA\$<tool>gcc 7.2.1 20170915[ 	]+0x00000000[ 	]+OPEN[ 	]+Applies to region from 0x100 to 0x110
-[ 	]+GA\*GOW:0x700[ 	]+0x00000000[ 	]+OPEN[ 	]+Applies to region from 0x100 to 0x110
-[ 	]+GA\*<stack prot>off[ 	]+0x00000000[ 	]+OPEN[ 	]+Applies to region from 0x100 to 0x110
-[ 	]+GA\*FORTIFY:0xff[ 	]+0x00000000[ 	]+OPEN[ 	]+Applies to region from 0x100 to 0x110
-[ 	]+GA\*<PIC>PIC[ 	]+0x00000000[ 	]+OPEN[ 	]+Applies to region from 0x100 to 0x110
-[ 	]+GA\!<short enum>false[ 	]+0x00000000[ 	]+OPEN[ 	]+Applies to region from 0x100 to 0x110
-[ 	]+GA\*<ABI>0x[0-9a-f]+[ 	]+0x00000000[ 	]+OPEN[ 	]+Applies to region from 0x100 to 0x110
-[ 	]+GA\*<stack prot>strong[ 	]+0x00000008[ 	]+func[ 	]+Applies to region from 0x108 to 0x10c.*
+[ 	]+GA\$<version>3p3[ 	]+0x00000008[ 	]+OPEN[ 	]+Applies to region from 0x10. to 0x110 \(note_4.s\)
+[ 	]+GA\$<tool>gcc 7.2.1 20170915[ 	]+0x00000000[ 	]+OPEN[ 	]+Applies to region from 0x10. to 0x110
+[ 	]+GA\*GOW:0x700[ 	]+0x00000000[ 	]+OPEN[ 	]+Applies to region from 0x10. to 0x110
+[ 	]+GA\*<stack prot>off[ 	]+0x00000000[ 	]+OPEN[ 	]+Applies to region from 0x10. to 0x110
+[ 	]+GA\*FORTIFY:0xff[ 	]+0x00000000[ 	]+OPEN[ 	]+Applies to region from 0x10. to 0x110
+[ 	]+GA\*<PIC>PIC[ 	]+0x00000000[ 	]+OPEN[ 	]+Applies to region from 0x10. to 0x110
+[ 	]+GA\!<short enum>false[ 	]+0x00000000[ 	]+OPEN[ 	]+Applies to region from 0x10. to 0x110
+[ 	]+GA\*<ABI>0x[0-9a-f]+[ 	]+0x00000000[ 	]+OPEN[ 	]+Applies to region from 0x10. to 0x110
+[ 	]+GA\*<stack prot>strong[ 	]+0x00000008[ 	]+func[ 	]+Applies to region from 0x10. to 0x10c.*
 #...
diff --git a/binutils/testsuite/binutils-all/note-4-32.s b/binutils/testsuite/binutils-all/note-4-32.s
index 09c5652..20d9e7b 100644
--- a/binutils/testsuite/binutils-all/note-4-32.s
+++ b/binutils/testsuite/binutils-all/note-4-32.s
@@ -1,6 +1,6 @@
 	.text
 	.org 0x100
-note_4.s:
+	.equiv note_4.s, . + 2
 	.dc.l 0
 	.dc.l 0
 
@@ -18,7 +18,7 @@ note_4.s_end:
 	.dc.l 8
 	.dc.l 0x100
 	.asciz "GA$
3p3"
-	.dc.l note_4.s
+	.dc.l note_4.s - 2
 	.dc.l note_4.s_end
 
 	.dc.l 23
diff --git a/binutils/testsuite/binutils-all/note-4-64.s b/binutils/testsuite/binutils-all/note-4-64.s
index 4f53298..1901682 100644
--- a/binutils/testsuite/binutils-all/note-4-64.s
+++ b/binutils/testsuite/binutils-all/note-4-64.s
@@ -1,6 +1,6 @@
 	.text
 	.org 0x100
-note_4.s:
+	.equiv note_4.s, . + 2
 	.dc.l 0
 	.dc.l 0
 	.dc.l 0
@@ -22,7 +22,7 @@ note_4.s_end:
 	.dc.l 16
 	.dc.l 0x100
 	.asciz "GA$
3p3"
-	.8byte note_4.s
+	.8byte note_4.s - 2
 	.8byte note_4.s_end
 
 	.dc.l 23