Add ability to follow dwo links to readelf/objdump.

	* dwarf.c (dwo_name, dwo_dir, dwo_id, dwo_id_len): New variables.
	(read_and_display_attr_value): Record dwo variables if requested.
	(display_augmentation_data): Rename to display_data and make
	generic.
	(load_dwo_file): New function.  Loads a separate dwarf object
	file.
	(load_separate_debug_file): Add reporting and loading of separate
	dwarf objet files.
	* readelf.c (process_section_headers): Add do_debug_links to list
	of flags requiring a debug dump.
	(display_debug_section): Tidy up code.
	* doc/debug.options.texi: Add note that dwo links will also be
	followed.
	* testsuite/binutils-all/debuglink.s: Tidy code.
	* testsuite/binutils-all/dwo.s: New test file.
	* testsuite/binutils-all/readelf.wk2: New file - expected output
	from readelf.
	* testsuite/binutils-all/readelf.exp: Run the new test.

4 files changed, 114 insertions, 20 deletions

diff --git a/binutils/testsuite/binutils-all/debuglink.s b/binutils/testsuite/binutils-all/debuglink.s
index a3691a0..daabf7a 100644
--- a/binutils/testsuite/binutils-all/debuglink.s
+++ b/binutils/testsuite/binutils-all/debuglink.s
@@ -17,14 +17,14 @@
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 	
-/* Create a fake .gnu_debuglink section.  */
+	/* Create a fake .gnu_debuglink section.  */
 
 	.section .gnu_debuglink,"",%progbits
 	.asciz "this_is_a_debuglink.debug"
 	.balign 4
 	.4byte 0x12345678
 
-/* Create a fake .gnu_debugaltlink section.  */
+	/* Create a fake .gnu_debugaltlink section.  */
 
 	.section .gnu_debugaltlink,"",%progbits
 	.asciz "linkdebug.debug"
@@ -32,9 +32,9 @@
 	.dc.b 0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff
 	.dc.b 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef
    
-/* Create a .debug_str section for local use.  This is also to check
-   the ability to dump the same section twice, if it exists in
-   both the main file and the separate debug info file.  */
+	/* Create a .debug_str section for local use.  This is also to check
+	   the ability to dump the same section twice, if it exists in
+	   both the main file and the separate debug info file.  */
 
 	.section	.debug_str,"MS",%progbits,1
 string1:
@@ -43,9 +43,9 @@ string1:
 	.balign	2
 string_end:
 	
-/* Create a .debug_info section that contains strings references into the
-   separate debug info file.  Plus the abbreviations are stored in the
-   separate file too...  */
+	/* Create a .debug_info section that contains string references into
+	   the separate debug info file.  Plus the abbreviations are stored
+	   in the separate file too...  */
 
 	.section	.debug_info,"",%progbits
 	.4byte	debugE - debugS	;# Length of Compilation Unit Info
diff --git a/binutils/testsuite/binutils-all/dwo.s b/binutils/testsuite/binutils-all/dwo.s
new file mode 100644
index 0000000..0d13471
--- /dev/null
+++ b/binutils/testsuite/binutils-all/dwo.s
@@ -0,0 +1,84 @@
+/* Assembler source used to create an object file for testing readelf's
+   and objdump's ability to process separate dwarf object files.
+
+   Copyright (C) 2017 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+	
+	/* Create a .debug_str section for local use.  This is also to check
+	   the ability to dump the same section twice, if it exists in
+	   both the main file and the separate debug info file.  */
+
+	.section	.debug_str,"MS",%progbits,1
+string1:
+	.asciz	"debugfile.dwo"
+string2:
+	.asciz  "/path/to/dwo/files"
+string3:
+	.asciz  "/another/path/"
+	.balign	2
+string_end:
+	
+	/* Create a .debug_info section that contains the dwo links.  */
+
+	.section	.debug_info,"",%progbits
+	.4byte	debugE - debugS	;# Length of Compilation Unit Info
+debugS:
+	.short	0x4	;# DWARF version number.
+	.4byte	0x0	;# Offset into .debug_abbrev section.
+	.byte	0x4	;# Pointer Size (in bytes).
+
+	.uleb128 0x1	;# Use abbrev #1.  This needs strings from the .debug_str section.
+	.4byte	string1
+	.4byte  string2
+
+	.uleb128 0x2	;# Use abbrev #2.
+	.asciz   "file.dwo"
+	.4byte   string3
+	.8byte   0x12345678aabbccdd
+
+	;# Minimal section alignment on alpha-* is 2, so ensure no new invalid CU
+	;# will be started.
+	.balign	2, 0
+debugE:
+
+	.section	.debug_abbrev,"",%progbits
+
+	/* Create an abbrev containing a DWARF5 style dwo link.  */
+	.uleb128 0x01	;# Abbrev code.
+	.uleb128 0x11	;# DW_TAG_compile_unit
+	.byte	 0x00	;# DW_children_no
+	.uleb128 0x76	;# DW_AT_dwo_name
+	.uleb128 0x0e	;# DW_FORM_strp
+	.uleb128 0x1b	;# DW_AT_comp_dir
+	.uleb128 0x0e	;# DW_FORM_strp
+	.byte	 0x00	;# End of abbrev
+	.byte	 0x00
+
+	/* Create an abbrev containing a GNU style dwo link.  */
+	.uleb128 0x02	;# Abbrev code.
+	.uleb128 0x11	;# DW_TAG_compile_unit
+	.byte	 0x00	;# DW_children_no
+	.uleb128 0x2130	;# DW_AT_GNU_dwo_name
+	.uleb128 0x08	;# DW_FORM_string
+	.uleb128 0x1b	;# DW_AT_comp_dir
+	.uleb128 0x0e	;# DW_FORM_strp
+	.uleb128 0x2131	;# DW_AT_GNU_dwo_id
+	.uleb128 0x07	;# DW_FORM_data8	
+	.byte	 0x00	;# End of abbrev
+	.byte	 0x00
+
+	.byte	 0x0	;# Abbrevs terminator
+
diff --git a/binutils/testsuite/binutils-all/readelf.exp b/binutils/testsuite/binutils-all/readelf.exp
index fdb310c..f126255 100644
--- a/binutils/testsuite/binutils-all/readelf.exp
+++ b/binutils/testsuite/binutils-all/readelf.exp
@@ -469,7 +469,7 @@ if {![binutils_assemble_flags $srcdir/$subdir/dwarf-attributes.S tmpdir/dwarf-at
 
 # Check that debug link sections can be dumped.
 if {![binutils_assemble $srcdir/$subdir/debuglink.s tmpdir/debuglink.o]} then {
-    unresolved "readelf --debug-dump=links (failed to assemble)"
+    unresolved "readelf --debug-dump=links (failed to assemble debuglink.s)"
 } else {
     if ![is_remote host] {
 	set tempfile tmpdir/debuglink.o
@@ -478,23 +478,29 @@ if {![binutils_assemble $srcdir/$subdir/debuglink.s tmpdir/debuglink.o]} then {
     }
 
     readelf_test {--debug-dump=links} $tempfile readelf.k  {}
-}
 
-# Check that debug link sections can be followed.
-if {![binutils_assemble $srcdir/$subdir/debuglink.s tmpdir/debuglink.o]} then {
-    unresolved "readelf --debug-dump=follow-links (failed to assemble1)"
-} else {
+    # Check that debug link sections can be followed.
     if {![binutils_assemble $srcdir/$subdir/linkdebug.s tmpdir/linkdebug.debug]} then {
-	unresolved "readelf --debug-dump=follow-links (failed to assemble2)"
+	unresolved "readelf --debug-dump=follow-links (failed to assemble linkdebug.s)"
     } else {
-	if ![is_remote host] {
-	    set tempfile tmpdir/debuglink.o
-	} else {
-	    set tempfile [remote_download host tmpdir/linkdebug.debug]
-	    set tempfile [remote_download host tmpdir/debuglink.o]
+	if [is_remote host] {
+	    set tempfile2 [remote_download host tmpdir/linkdebug.debug]
 	}
 
 	readelf_test {-wKis} $tempfile objdump.WK2  {}
     }
 }
 
+if {![binutils_assemble $srcdir/$subdir/dwo.s tmpdir/dwo.o]} then {
+    unresolved "readelf --debug-dump=links (failed to assemble dwo.s)"
+} else {
+    if ![is_remote host] {
+	set tempfile tmpdir/dwo.o
+    } else {
+	set tempfile [remote_download host tmpdir/dwo.o]
+    }
+
+    readelf_test {--debug-dump=links} $tempfile readelf.k2  {}
+}
+
+
diff --git a/binutils/testsuite/binutils-all/readelf.k2 b/binutils/testsuite/binutils-all/readelf.k2
new file mode 100644
index 0000000..89ee4b4
--- /dev/null
+++ b/binutils/testsuite/binutils-all/readelf.k2
@@ -0,0 +1,4 @@
+The \.debug_info section contains a link to a dwo file:
+  Name:      file\.dwo
+  Directory: /another/path/
+  ID:        (12|dd) (34|cc) (56|bb) (78|aa) (78|aa) (56|bb) (34|cc) (12|dd)