Fix readelf's and objdump's dislplay of DWO links when multiple links are present.

PR 26829
 * dwarf.c (struct dwo_info): Add cu_offset field.
 (add_dwo_info): Add cu_offset parameter.  Record in new dwo_info
 struct.
 (add_dwo_name): Add cu_offset field.
 (add_dwo_dir): Add cu_offset field.
 (add_dwo_id): Add cu_offset field.
 (read_and_display_attr_value): Pass cu_offset to dwo recording
 functions.
 (load_separate_debug_files): Accumulate name, dir and id values
 and display once for each CU.
 * testsuite/binutils-all/dwo.sL Use a separate CU for the second
 dwo link.
 * testsuite/binutils-all/readelf.k2: Update expected output.

binutils/testsuite/binutils-all/dwo.s

@@ -34,8 +34,8 @@ 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:
+	.4byte	debugE1 - debugS1	;# Length of Compilation Unit Info
+debugS1:
 	.short	0x4	;# DWARF version number.
 	.4byte	0x0	;# Offset into .debug_abbrev section.
 	.byte	0x4	;# Pointer Size (in bytes).
@@ -43,6 +43,13 @@ debugS:
 	.uleb128 0x1	;# Use abbrev #1.  This needs strings from the .debug_str section.
 	.4byte	string1
 	.4byte  string2
+debugE1:
+
+	.4byte	debugE2 - debugS2	;# Length of Compilation Unit Info
+debugS2:
+	.short	0x4	;# DWARF version number.
+	.4byte	0x0	;# Offset into .debug_abbrev section.
+	.byte	0x4	;# Pointer Size (in bytes).
 
 	.uleb128 0x2	;# Use abbrev #2.
 	.asciz   "file.dwo"
@@ -52,7 +59,7 @@ debugS:
 	;# Minimal section alignment on alpha-* is 2, so ensure no new invalid CU
 	;# will be started.
 	.balign	2, 0
-debugE:
+debugE2:
 
 	.section	.debug_abbrev,"",%progbits
 

binutils/testsuite/binutils-all/readelf.k2

@@ -6,4 +6,4 @@ The \.debug_info section contains link\(s\) to dwo file\(s\):
 
   Name:      debugfile\.dwo
   Directory: /path/to/dwo/files
-  ID:        (12|dd) (34|cc) (56|bb) (78|aa) (78|aa) (56|bb) (34|cc) (12|dd)
+  ID:        <not specified>