libdw: Handle DWARF5 line tables in dwarf_getsrclines.

In DWARF5 the actual line number table format doesn't change, except for
not allowing DW_LNE_define_file (but we still just accept it). The
changes are the header having new fields for address and segment
selector sizes, and new formats for the directory and file names tables.

The directory and file name tables are much more flexible in DWARF5, but
we only interpret the actual names and file/dir index relationships,
skipping/ignoring any other information. There also is no new interface
yet to get at the new directory and file properties.

There is some small confusion about the file name table indexing. Older
DWARF versions explicitly called the first file name table 1. DWARF5
implies the first index is 0 (but for file attributes, zero means not
associated with a file). We get away with that by having an actual zero
index for older DWARF versions (the null_fill). It looks like gcc gets
around it by explicitly duplicating the first (0) and second (1) file
name entry in the table. This can also be seen in the new testcase.

The patch looks big because of moving a few initializations around
and because the code that is different for older/newer DWARF got moved
under if statements. But the original old DWARF code path didn't really
change.

Signed-off-by: Mark Wielaard <mark@klomp.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/libdw/dwarf.h b/libdw/dwarf.h
index 99cc1128..fc9801bd 100644
--- a/libdw/dwarf.h
+++ b/libdw/dwarf.h
@@ -783,6 +783,17 @@ enum
     DW_DEFAULTED_out_of_class = 2
   };
 
+/* DWARF line content descriptions.  */
+enum
+  {
+    DW_LNCT_path = 0x1,
+    DW_LNCT_directory_index = 0x2,
+    DW_LNCT_timestamp = 0x3,
+    DW_LNCT_size = 0x4,
+    DW_LNCT_MD5 = 0x5,
+    DW_LNCT_lo_user = 0x2000,
+    DW_LNCT_hi_user = 0x3fff
+  };
 
 /* DWARF standard opcode encodings.  */
 enum