gas: Use the directory name in .file 0

DWARF5 allows .file 0 to take an optional directory name.  Set the entry
0 of the directory table to the directory name in .file 0.

	PR gas/28266
	* dwarf2dbg.c (get_directory_table_entry): Add an argument for
	the directory name in .file 0 and use it, instead of PWD.
	(allocate_filenum): Pass NULL to get_directory_table_entry.
	(allocate_filename_to_slot): Pass the incoming dirname to
	get_directory_table_entry.
	* testsuite/gas/elf/dwarf-5-file0-2.d: New file.
	* testsuite/gas/elf/dwarf-5-file0-2.s: Likewise.
	* testsuite/gas/elf/elf.exp: Run dwarf-5-file0-2.

4 files changed, 135 insertions, 4 deletions

diff --git a/gas/dwarf2dbg.c b/gas/dwarf2dbg.c
index 8f52485..9e3437b 100644
--- a/gas/dwarf2dbg.c
+++ b/gas/dwarf2dbg.c
@@ -592,6 +592,7 @@ get_basename (const char * pathname)
 
 static unsigned int
 get_directory_table_entry (const char *dirname,
+			   const char *file0_dirname,
 			   size_t dirlen,
 			   bool can_use_zero)
 {
@@ -621,7 +622,7 @@ get_directory_table_entry (const char *dirname,
     {
       if (dirs == NULL || dirs[0] == NULL)
 	{
-	  const char * pwd = getpwd ();
+	  const char * pwd = file0_dirname ? file0_dirname : getpwd ();
 
 	  if (dwarf_level >= 5 && strcmp (dirname, pwd) != 0)
 	    {
@@ -630,7 +631,8 @@ get_directory_table_entry (const char *dirname,
 		 directory).  Since we are about to create a directory entry that
 		 is not the same, allocate the current directory first.
 		 FIXME: Alternatively we could generate an error message here.  */
-	      (void) get_directory_table_entry (pwd, strlen (pwd), true);
+	      (void) get_directory_table_entry (pwd, NULL, strlen (pwd),
+						true);
 	      d = 1;
 	    }
 	  else
@@ -726,7 +728,7 @@ allocate_filenum (const char * pathname)
   file = get_basename (pathname);
   dir_len = file - pathname;
 
-  dir = get_directory_table_entry (pathname, dir_len, false);
+  dir = get_directory_table_entry (pathname, NULL, dir_len, false);
 
   /* Do not use slot-0.  That is specifically reserved for use by
      the '.file 0 "name"' directive.  */
@@ -766,6 +768,7 @@ allocate_filename_to_slot (const char *dirname,
   const char *file;
   size_t dirlen;
   unsigned int i, d;
+  const char *file0_dirname = dirname;
 
   /* Short circuit the common case of adding the same pathname
      as last time.  */
@@ -856,7 +859,8 @@ allocate_filename_to_slot (const char *dirname,
       file = filename;
     }
 
-  d = get_directory_table_entry (dirname, dirlen, num == 0);
+  d = get_directory_table_entry (dirname, file0_dirname, dirlen,
+				 num == 0);
   i = num;
 
   if (! assign_file_to_slot (i, file, d))
diff --git a/gas/testsuite/gas/elf/dwarf-5-file0-2.d b/gas/testsuite/gas/elf/dwarf-5-file0-2.d
new file mode 100644
index 0000000..4b3ed29
--- /dev/null
+++ b/gas/testsuite/gas/elf/dwarf-5-file0-2.d
@@ -0,0 +1,15 @@
+#as: --gdwarf-5
+#name: DWARF5 .file 0 dir file
+#readelf: -wl
+
+#...
+ The Directory Table \(offset 0x.*, lines 1, columns 1\):
+  Entry	Name
+#...
+  0	\(indirect line string, offset: 0x.*\): /example
+
+ The File Name Table \(offset 0x.*, lines 2, columns 2\):
+  Entry	Dir	Name
+  0	0	\(indirect line string, offset: 0x.*\): test.c
+  1	0	\(indirect line string, offset: 0x.*\): test.c
+#pass
diff --git a/gas/testsuite/gas/elf/dwarf-5-file0-2.s b/gas/testsuite/gas/elf/dwarf-5-file0-2.s
new file mode 100644
index 0000000..135a03b
--- /dev/null
+++ b/gas/testsuite/gas/elf/dwarf-5-file0-2.s
@@ -0,0 +1,111 @@
+	.file	"test.c"
+	.text
+.Ltext0:
+	.file 0 "/example" "test.c"
+	.globl	x
+	.section	.bss
+	.balign 4
+	.type	x, @object
+	.size	x, 4
+x:
+	.zero	4
+	.text
+.Letext0:
+	.file 1 "test.c"
+	.section	.debug_info,"",%progbits
+.Ldebug_info0:
+	.long	0x32
+	.2byte	0x5
+	.byte	0x1
+	.byte	0x4
+	.long	.Ldebug_abbrev0
+	.uleb128 0x1
+	.long	.LASF2
+	.byte	0x1d
+	.long	.LASF0
+	.long	.LASF1
+	.long	.Ldebug_line0
+	.uleb128 0x2
+	.string	"x"
+	.byte	0x1
+	.byte	0x1
+	.byte	0x5
+	.long	0x2e
+	.uleb128 0x5
+	.byte	0x3
+	.long	x
+	.uleb128 0x3
+	.byte	0x4
+	.byte	0x5
+	.string	"int"
+	.byte	0
+	.section	.debug_abbrev,"",%progbits
+.Ldebug_abbrev0:
+	.uleb128 0x1
+	.uleb128 0x11
+	.byte	0x1
+	.uleb128 0x25
+	.uleb128 0xe
+	.uleb128 0x13
+	.uleb128 0xb
+	.uleb128 0x3
+	.uleb128 0x1f
+	.uleb128 0x1b
+	.uleb128 0x1f
+	.uleb128 0x10
+	.uleb128 0x17
+	.byte	0
+	.byte	0
+	.uleb128 0x2
+	.uleb128 0x34
+	.byte	0
+	.uleb128 0x3
+	.uleb128 0x8
+	.uleb128 0x3a
+	.uleb128 0xb
+	.uleb128 0x3b
+	.uleb128 0xb
+	.uleb128 0x39
+	.uleb128 0xb
+	.uleb128 0x49
+	.uleb128 0x13
+	.uleb128 0x3f
+	.uleb128 0x19
+	.uleb128 0x2
+	.uleb128 0x18
+	.byte	0
+	.byte	0
+	.uleb128 0x3
+	.uleb128 0x24
+	.byte	0
+	.uleb128 0xb
+	.uleb128 0xb
+	.uleb128 0x3e
+	.uleb128 0xb
+	.uleb128 0x3
+	.uleb128 0x8
+	.byte	0
+	.byte	0
+	.byte	0
+	.section	.debug_aranges,"",%progbits
+	.long	0x14
+	.2byte	0x2
+	.long	.Ldebug_info0
+	.byte	0x4
+	.byte	0
+	.2byte	0
+	.2byte	0
+	.long	0
+	.long	0
+	.section	.debug_line,"",%progbits
+.Ldebug_line0:
+	.section	.debug_str,"MS",%progbits,1
+.LASF2:
+	.string	"GNU C17 11.2.1 -g"
+	.section	.debug_line_str,"MS",%progbits,1
+.LASF1:
+	.string	"/example"
+.LASF0:
+	.string	"test.c"
+	.ident	"GCC: (GNU) 11.2.1"
+	.section	.note.GNU-stack,"",%progbits
diff --git a/gas/testsuite/gas/elf/elf.exp b/gas/testsuite/gas/elf/elf.exp
index 18bc1db..2485008 100644
--- a/gas/testsuite/gas/elf/elf.exp
+++ b/gas/testsuite/gas/elf/elf.exp
@@ -297,6 +297,7 @@ if { [is_elf_format] } then {
     run_dump_test "dwarf2-19" $dump_opts
     run_dump_test "dwarf2-20" $dump_opts
     run_dump_test "dwarf-5-file0" $dump_opts
+    run_dump_test "dwarf-5-file0-2" $dump_opts
     run_dump_test "dwarf-5-dir0" $dump_opts
     run_dump_test "dwarf-4-cu" $dump_opts
     run_dump_test "dwarf-5-cu" $dump_opts