[PATCH] binutils/dwarf: Print embedded source, when available

[Will Hawkins]

When an object file with debugging information has the source embedded
(via DW_LNCT_LLVM_source), the `--dwarf=rawline` output from objdump
prints the source but the format leaves something to be desired.

This small patch makes it so that the source is printed started on a 
new line in the File Name Table when the user invokes `objdump` with
`--dwarf=rawline`.

The DW_LNCT_LLVM_source line number header entry format is slated to
be added to DWARFv6: https://dwarfstd.org/issues/180201.1.html and
lldb supports it (and gdb will soon support it).

If this is a feature that seems worthwhile, I would be more than happy
to add tests. I just didn't want to waste anyone's time with a long(ish)
patch at first.

I tried to follow all the proper coding style requirements, but I am
sure that there is something that I missed! Sorry in advance!

---
 binutils/dwarf.c | 32 ++++++++++++++++++++++++++------
 include/dwarf2.h |  1 +
 2 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/binutils/dwarf.c b/binutils/dwarf.c
index fa8dce25..fbf42c29 100644
--- a/binutils/dwarf.c
+++ b/binutils/dwarf.c
@@ -5776,7 +5776,7 @@ display_formatted_table (unsigned char *data,
 {
   unsigned char *format_start, format_count, *format, formati;
   uint64_t data_count, datai;
-  unsigned int namepass, last_entry = 0;
+  unsigned int namepass, namesourcepass, last_entry = 0;
   const char * table_name = is_dir ? N_("Directory Table") : N_("File Name Table");
 
   SAFE_BYTE_GET_AND_INC (format_count, data, 1, end);
@@ -5847,6 +5847,9 @@ display_formatted_table (unsigned char *data,
 	      case DW_LNCT_MD5:
 		printf (_("\tMD5\t\t\t"));
 		break;
+	      case DW_LNCT_LLVM_source:
+		// Skip source ... display on next line.
+		break;
 	      default:
 		printf (_("\t(Unknown format content type %" PRIu64 ")"),
 			content_type);
@@ -5861,8 +5864,9 @@ display_formatted_table (unsigned char *data,
       unsigned char *datapass = data;
 
       printf ("  %d", last_entry++);
-      /* Delay displaying name as the last entry for better screen layout.  */
-      for (namepass = 0; namepass < 2; namepass++)
+      /* Delay displaying name/source as the last entry for better screen
+	 layout.  */
+      for (namesourcepass = 0; namesourcepass < 3; namesourcepass++)
 	{
 	  format = format_start;
 	  data = datapass;
@@ -5872,13 +5876,29 @@ display_formatted_table (unsigned char *data,
 
 	      READ_ULEB (content_type, format, end);
 	      READ_ULEB (form, format, end);
-	      bool do_loc = (content_type == DW_LNCT_path) != (namepass == 1);
+
+	      bool do_loc = (content_type == DW_LNCT_path)
+		!= (namesourcepass == 1);
+	      do_loc |= (content_type == DW_LNCT_LLVM_source)
+		!= (namesourcepass == 2);
+
+	      char delimiter = '\t';
+
+	      /* Print Source last (if available) and print it
+		 starting on the next line.  */
+	      if (namesourcepass == 2 && content_type == DW_LNCT_LLVM_source)
+		{
+		  delimiter = ' ';
+		  putchar ('\n');
+		  printf ("  Source:");
+		}
 	      data = read_and_display_attr_value (0, form, 0, start, data, end,
 						  0, linfo->li_address_size,
 						  linfo->li_offset_size,
 						  linfo->li_version, NULL,
-						  do_loc, section, NULL, '\t',
-						  -1, false, 0, 0, false);
+						  do_loc, section, NULL,
+						  delimiter, -1, false, 0, 0,
+						  false);
 	    }
 	}
 
diff --git a/include/dwarf2.h b/include/dwarf2.h
index bf9287f1..ee546a40 100644
--- a/include/dwarf2.h
+++ b/include/dwarf2.h
@@ -294,6 +294,7 @@ enum dwarf_line_number_content_type
     DW_LNCT_size = 0x4,
     DW_LNCT_MD5 = 0x5,
     DW_LNCT_lo_user = 0x2000,
+    DW_LNCT_LLVM_source = 0x2001,
     DW_LNCT_hi_user = 0x3fff
   };
 
-- 
2.49.0