Make dwarf_expr_context's destructor virtual

Ref: https://sourceware.org/ml/gdb-patches/2016-10/msg00662.html

 $ make WERROR_CFLAGS="-Wnon-virtual-dtor" dwarf2expr.o
 ...
 In file included from .../src/gdb/dwarf2expr.c:28:0:
 .../src/gdb/dwarf2expr.h:68:8: warning: ‘struct dwarf_expr_context’ has virtual functions and accessible non-virtual destructor [-Wnon-virtual-dtor]
  struct dwarf_expr_context
	 ^~~~~~~~~~~~~~~~~~

Happens to not be a problem in practice currently because concrete
subclasses are allocated on the stack.  I.e., we don't ever delete
objects of types that derive from dwarf_expr_context through pointers
to dwarf_expr_context.

gdb/ChangeLog:
2016-10-25  Pedro Alves  <palves@redhat.com>

	* dwarf2expr.h (struct dwarf_expr_context) <~dwarf_expr_context>:
	Make virtual.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 10d6866..91f36f9 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2016-10-25  Pedro Alves  <palves@redhat.com>
+
+       * dwarf2expr.h (struct dwarf_expr_context) <~dwarf_expr_context>:
+       Make virtual.
+
 2016-10-25  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
 
        PR build/20712

diff --git a/gdb/dwarf2expr.h b/gdb/dwarf2expr.h
index 7bf194a..3d08120 100644 (file)
--- a/gdb/dwarf2expr.h
+++ b/gdb/dwarf2expr.h
@@ -68,7 +68,7 @@ struct dwarf_stack_value
 struct dwarf_expr_context
 {
   dwarf_expr_context ();
-  ~dwarf_expr_context ();
+  virtual ~dwarf_expr_context ();
 
   void push_address (CORE_ADDR value, int in_stack_memory);
   void eval (const gdb_byte *addr, size_t len);