[binutils-gdb] Fix DWARF disassembly of DW_OP_const_type

[gdb-buildbot@sergiodj.net]

*** TEST RESULTS FOR COMMIT d9e49b61691f384447242f54c996fe80ef9bf184 ***

commit d9e49b61691f384447242f54c996fe80ef9bf184
Author:     Tom Tromey <tromey@adacore.com>
AuthorDate: Fri Apr 3 09:11:55 2020 -0600
Commit:     Tom Tromey <tromey@adacore.com>
CommitDate: Fri Apr 3 09:15:41 2020 -0600

    Fix DWARF disassembly of DW_OP_const_type
    
    While debugging another issue, I noticed that disassembling a DWARF
    expression using DW_OP_const_type did not work.
    disassemble_dwarf_expression was not properly decoding this operation.
    
    This patch fixes the problem.  Tested by re-debugging gdb.
    
    I didn't write a test case because that seemed like overkill for
    what's essentially a maintainer's helper.
    
    The expression evaluator does decode this properly, so no other change
    was needed.
    
    gdb/ChangeLog
    2020-04-03  Tom Tromey  <tromey@adacore.com>
    
            * dwarf2/loc.c (disassemble_dwarf_expression) <DW_OP_const_type>:
            Read constant block.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index e93725129d..86d949b212 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2020-04-03  Tom Tromey  <tromey@adacore.com>
+
+	* dwarf2/loc.c (disassemble_dwarf_expression) <DW_OP_const_type>:
+	Read constant block.
+
 2020-04-02  Simon Marchi  <simon.marchi@polymtl.ca>
 
 	* gdb_bfd.h: Include gdbsupport/byte-vector.h.
diff --git a/gdb/dwarf2/loc.c b/gdb/dwarf2/loc.c
index 6440335ccb..fc54e16ffd 100644
--- a/gdb/dwarf2/loc.c
+++ b/gdb/dwarf2/loc.c
@@ -4082,6 +4082,12 @@ disassemble_dwarf_expression (struct ui_file *stream,
 	    type_print (type, "", stream, -1);
 	    fprintf_filtered (stream, " [0x%s]>",
 			      phex_nz (to_underlying (type_die), 0));
+
+	    int n = *data++;
+	    fprintf_filtered (stream, " %d byte block:", n);
+	    for (int i = 0; i < n; ++i)
+	      fprintf_filtered (stream, " %02x", data[i]);
+	    data += n;
 	  }
 	  break;