[PATCH] readelf: Handle DW_LLE_GNU_view_pair

[Mark Wielaard]

DW_LLE_GNU_view_pair is used by gcc -gvariable-location-views=incompat5.
As described in http://www.fsfla.org/~lxoliva/papers/sfn/dwarf6-sfn-lvu.txt
and proposed for DWARF6 https://dwarfstd.org/ShowIssue.php?issue=170427.1

Signed-off-by: Mark Wielaard <m...@klomp.org>
---
 libdw/ChangeLog |  4 ++++
 libdw/dwarf.h   |  6 +++++-
 src/ChangeLog   |  6 ++++++
 src/readelf.c   | 12 ++++++++++++
 4 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/libdw/ChangeLog b/libdw/ChangeLog
index b14b5383..2efcaeb9 100644
--- a/libdw/ChangeLog
+++ b/libdw/ChangeLog
@@ -1,3 +1,7 @@
+2022-10-19  Mark Wielaard  <m...@klomp.org>
+
+       * dwarf.h (DW_LLE_GNU_view_pair): New constant.
+
 2022-09-20  Yonggang Luo  <luoyongg...@gmail.com>
 
        * memory-access.h: Use BYTE_ORDER, LITTLE_ENDIAN and BIG_ENDIAN.
diff --git a/libdw/dwarf.h b/libdw/dwarf.h
index c961bc36..b2e49db2 100644
--- a/libdw/dwarf.h
+++ b/libdw/dwarf.h
@@ -931,7 +931,11 @@ enum
     DW_LLE_GNU_end_of_list_entry = 0x0,
     DW_LLE_GNU_base_address_selection_entry = 0x1,
     DW_LLE_GNU_start_end_entry = 0x2,
-    DW_LLE_GNU_start_length_entry = 0x3
+    DW_LLE_GNU_start_length_entry = 0x3,
+
+    // http://www.fsfla.org/~lxoliva/papers/sfn/dwarf6-sfn-lvu.txt
+    // https://dwarfstd.org/ShowIssue.php?issue=170427.1
+    DW_LLE_GNU_view_pair = 0x9
   };
 
 /* DWARF5 package file section identifiers.  */
diff --git a/src/ChangeLog b/src/ChangeLog
index 23c971d1..1f369ef6 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,9 @@
+2022-10-19  Mark Wielaard  <m...@klomp.org>
+
+       * readelf.c (dwarf_loc_list_encoding_string): Handle
+       DW_LLE_GNU_view_pair.
+       (print_debug_loclists_section): Likewise.
+
 2022-09-20  Yonggang Luo  <luoyongg...@gmail.com>
 
        * arlib.h: Use BYTE_ORDER, LITTLE_ENDIAN and BIG_ENDIAN.
diff --git a/src/readelf.c b/src/readelf.c
index a206e60e..7671a31d 100644
--- a/src/readelf.c
+++ b/src/readelf.c
@@ -4185,6 +4185,8 @@ dwarf_loc_list_encoding_string (unsigned int kind)
 #define DWARF_ONE_KNOWN_DW_LLE(NAME, CODE) case CODE: return #NAME;
       DWARF_ALL_KNOWN_DW_LLE
 #undef DWARF_ONE_KNOWN_DW_LLE
+    /* DW_LLE_GNU_view_pair is special/incompatible with default codes.  */
+    case DW_LLE_GNU_view_pair: return "GNU_view_pair";
     default:
       return NULL;
     }
@@ -9744,6 +9746,16 @@ print_debug_loclists_section (Dwfl_Module *dwflmod,
              readp += len;
              break;
 
+           case DW_LLE_GNU_view_pair:
+             if ((uint64_t) (nexthdr - readp) < 1)
+               goto invalid_entry;
+             get_uleb128 (op1, readp, nexthdr);
+             if ((uint64_t) (nexthdr - readp) < 1)
+               goto invalid_entry;
+             get_uleb128 (op2, readp, nexthdr);
+             printf (" %" PRIx64 ", %" PRIx64 "\n", op1, op2);
+             break;
+
            default:
              goto invalid_entry;
            }
-- 
2.30.2